Morphology and stratal geometry of the Antarctic continental shelf: Insights from models

USGS Publications Warehouse

Cooper, Alan K.; Barker, Peter F.; Brancolini, Giuliano

1997-01-01

Reconstruction of past ice-sheet fluctuations from the stratigraphy of glaciated continental shelves requires understanding of the relationships among the stratal geometry, glacial and marine sedimentary processes, and ice dynamics. We investigate the formation of the morphology and the broad stratal geometry of topsets on the Antarctic continental shelf with numerical models. Our models assume that the stratal geometry and morphology are principally the results of time-integrated effects of glacial erosion and sedimentation related to the location of the seaward edge of the grounded ice. The location of the grounding line varies with time almost randomly across the shelf. With these simple assumptions, the models can successfully mimic salient features of the morphology and the stratal geometry. The models suggest that the current shelf has gradually evolved to its present geometry by many glacial advances and retreats of the grounding line to different locations across the shelf. The locations of the grounding line do not appear to be linearly correlated with either fluctuations in the 5 l s O record (which presumably represents changes in the global ice volume) or with the global sea-level curve, suggesting that either a more complex relationship exists or local effects dominate. The models suggest that erosion of preglacial sediments is confined to the inner shelf, and erosion decreases and deposition increases toward the shelf edge. Some of the deposited glacial sediments must be derived from continental erosion. The sediments probably undergo extensive transport and reworking obliterating much of the evidence for their original depositional environment. The flexural rigidity and the tectonic subsidence of the underlying lithosphere modify the bathymetry of the shelf, but probably have little effect on the stratal geometry. Our models provide several guidelines for the interpretation of unconformities, the nature of preserved topset deposits, and the significance of progradation versus aggradation of shelf sediments.

Tectonic signatures on active margins

NASA Astrophysics Data System (ADS)

Hogarth, Leah Jolynn

High-resolution Compressed High-Intensity Radar Pulse (CHIRP) surveys offshore of La Jolla in southern California and the Eel River in northern California provide the opportunity to investigate the role of tectonics in the formation of stratigraphic architecture and margin morphology. Both study sites are characterized by shore-parallel tectonic deformation, which is largely observed in the structure of the prominent angular unconformity interpreted as the transgressive surface. Based on stratal geometry and acoustic character, we identify three sedimentary sequences offshore of La Jolla: an acoustically laminated estuarine unit deposited during early transgression, an infilling or "healing-phase" unit formed during the transgression, and an upper transparent unit. The estuarine unit is confined to the canyon edges in what may have been embayments during the last sea-level rise. The healing-phase unit appears to infill rough areas on the transgressive surface that may be related to relict fault structures. The upper transparent unit is largely controlled by long-wavelength tectonic deformation due to the Rose Canyon Fault. This unit is also characterized by a mid-shelf (˜40 m water depth) thickness high, which is likely a result of hydrodynamic forces and sediment grain size. On the Eel margin, we observe three distinct facies: a seaward-thinning unit truncated by the transgressive surface, a healing-phase unit confined to the edges of a broad structural high, and a highly laminated upper unit. The seaward-thinning wedge of sediment below the transgressive surface is marked by a number of channels that we interpret as distributary channels based on their morphology. Regional divergence of the sequence boundary and transgressive surface with up to ˜8 m of sediment preserved across the interfluves suggests the formation of subaerial accommodation during the lowstand. The healing-phase, much like that in southern California, appears to infill rough areas in the transgressive surface. Reflectors within the laminated upper unit exhibit divergence towards the Eel River Syncline, which suggests that deposition in the syncline is syntectonic. The transgressive surface is offset across the Eureka Anticline indicating deformation has occurred since ˜10 ka. The relief observed along the transgressive surface is consistent with deformation rates measured onshore.

DOE Office of Scientific and Technical Information (OSTI.GOV)

McGinnis, J.P.; Karner, G.D.; Driscoll, N.W.

The tectonic and stratigraphic development of the Congo continental margin reflects the timing, magnitude, and distribution of lithospheric extension responsible for its formation. Details of the lithospheric extension process are recorded in the stratigraphic successions preserved along and across the margin. By using the stratal relationships (e.g., onlap, downlap, and truncation) and lithofacies determined from seismic reflection and exploratory well data as input into our basin-modeling strategy, we have developed an integrated approach to determine the relationship between the timing, magnitude, and distribution of lithospheric extension across the margin. Two hinge zones, an eastern and Atlantic hinge formed along themore » Congo margin in response to discrete extensional events occurring from the Berriasian to the Aptian. The eastern hinge zone demarcates the eastern limit of the broadly distributed Berriasian extension. This extension resulted in the formation of deep anoxic, lacustrine systems. In contrast, the Atlantic hinge, located [approximately]90 km west of the eastern hinge, marks the eastern limit of a second phase of extension, which began in the Hauterivian. Consequent footwall uplift and rotation exposed the earlier synrift and prerift stratigraphy to at least wave base causing varying amounts of erosional truncation across the Atlantic hinge zone along much of the Gabon, Congo, and Angola margins. The absence of the Melania Formation across the Congo margin implies that uplift of the Atlantic hinge was relatively minor compared to that across the Angola and Gabon margins. In addition, material eroded from the adjacent and topographically higher hinge zones may in part account for the thick wedge of sediment deposited seaward of the Congo Atlantic hinge. A third phase of extension reactivated both the eastern and Atlantic hinge zones and was responsible for creating the accommodation space for Marnes Noires source rock deposition.« less

Deposystem architectures and lithofacies of a submarine fan-dominated deep sea succession in an orogen: A case study from the Upper Triassic Langjiexue Group of southern Tibet

NASA Astrophysics Data System (ADS)

Zhang, Chaokai; Li, Xianghui; Mattern, Frank; Mao, Guozheng; Zeng, Qinggao; Xu, Wenli

2015-11-01

Over thirty stratigraphic sections of the Himalaya orogen Upper Triassic Langjiexue Group in southern Tibet, China, were studied to interpret the environments and lithofacies. The facies associations channel (A), lobe (B), levee-interchannel (C), and basin plain (D) with nine facies (A1-3, B1-3, and C1-3) were distinguished. They form six architectural elements: channel-interchannel, overbank-levee, crevasse-splay, outer fan-lobe, fan-fringe, and basin plain. Taking into account the facies analysis, (sub-) deposystem correlation, paleocurrent dispersal pattern, and restoration of primary stratal width, the Langjiexue Group displays the architecture of a coalescing submarine fan-dominated deep sea deposystem, measuring about 400-500 km × 600-700 km in size or even more, one of the largest pre-Cenozoic submarine fans ever reported. Subdivisionally, four fans, lacking inner fans, could have coalesced laterally within the submarine fan deposystem, and at least six submarine fan developments were vertically succeeded by mid- to outer-fan deposits with progradational to retrogradational successions. According to the range of 30-70% of sandstone content, the fan deposystem is mud- and sand-rich, suggesting a medium-far (over 400-600 km) transport of sediment from the source area.

Seismic analysis of clinoform depositional sequences and shelf-margin trajectories in Lower Cretaceous (Albian) strata, Alaska North Slope

USGS Publications Warehouse

Houseknecht, D.W.; Bird, K.J.; Schenk, C.J.

2009-01-01

Lower Cretaceous strata beneath the Alaska North Slope include clinoform depositional sequences that filled the western Colville foreland basin and overstepped the Beaufort rift shoulder. Analysis of Albian clinoform sequences with two-dimensional (2D) seismic data resulted in the recognition of seismic facies inferred to represent lowstand, transgressive and highstand systems tracts. These are stacked to produce shelf-margin trajectories that appear in low-resolution seismic data to alternate between aggradational and progradational. Higher-resolution seismic data reveal shelf-margin trajectories that are more complex, particularly in net-aggradational areas, where three patterns commonly are observed: (1) a negative (downward) step across the sequence boundary followed by mostly aggradation in the lowstand systems tract (LST), (2) a positive (upward) step across the sequence boundary followed by mostly progradation in the LST and (3) an upward backstep across a mass-failure d??collement. These different shelf-margin trajectories are interpreted as (1) fall of relative sea level below the shelf edge, (2) fall of relative sea level to above the shelf edge and (3) mass-failure removal of shelf-margin sediment. Lowstand shelf margins mapped using these criteria are oriented north-south in the foreland basin, indicating longitudinal filling from west to east. The shelf margins turn westward in the north, where the clinoform depositional system overstepped the rift shoulder, and turn eastward in the south, suggesting progradation of depositional systems from the ancestral Brooks Range into the foredeep. Lowstand shelf-margin orientations are consistently perpendicular to clinoform-foreset-dip directions. Although the Albian clinoform sequences of the Alaska North Slope are generally similar in stratal geometry to clinoform sequences elsewhere, they are significantly thicker. Clinoform-sequence thickness ranges from 600-1000 m in the north to 1700-2000 m in the south, reflecting increased accommodation from the rift shoulder into the foredeep. The unusually thick clinoform sequences suggest significant subsidence followed by rapid sediment influx. No claim to original US government works. Journal Compilation ?? Blackwell Publishing Ltd, European Association of Geoscientists & Engineers and International Association of Sedimentologists.

Mechanisms and processes of stratal disruption and mixing in the development of mélanges and broken formations: Redefining and classifying mélanges

NASA Astrophysics Data System (ADS)

Festa, A.; Dilek, Y.; Pini, G. A.; Codegone, G.; Ogata, K.

2012-09-01

The terms mélange and broken formation have been used in different ways in the literature. The lack of agreement on their definition often leads to confusion and misinterpretations. An evaluation of the various uses of these terms allows us to consider several types of chaotic rock bodies originated by tectonic, sedimentary and diapiric processes in different tectonic settings. Our review of stratal disruption and mixing processes shows that there exists a continuum of deformation structures and processes in the generation of mélanges and broken formations. This continuum is directly controlled by the increase of the degree of consolidation with burial. In tectonically active environments, at the shallow structural levels, the occurrence of poorly consolidated sediments favors gravitational deformation. At deeper structural levels, the deformation related to tectonic forces becomes gradually more significant with depth. Sedimentary (and diapiric) mélanges and broken formations represent the products of punctuated stratal disruption mechanisms recording the instantaneous physical conditions in the geological environment at the time of their formation. The different kinematics, the composition and lithification degree of sediments, the geometry and morphology of the basins, and the mode of failure propagation control the transition between different types of mass-transported chaotic bodies, the style of stratal disruption, and the amount of rock mixing. Tectonically broken formations and mélanges record a continuum of deformation that occurs through time and different degrees of lithification during a progressive increase of the degree of consolidation and of the diagenetic and metamorphic mineral transformation. Systematic documentation of the mechanisms and processes of the formation of different broken formations and mélanges and their interplay in time and space are highly important to increase the understanding of the evolutionary history of accretionary wedges and orogenic belts.

The importance of structural softening for the evolution and architecture of passive margins

PubMed Central

Duretz, T.; Petri, B.; Mohn, G.; Schmalholz, S. M.; Schenker, F. L.; Müntener, O.

2016-01-01

Lithospheric extension can generate passive margins that bound oceans worldwide. Detailed geological and geophysical studies in present and fossil passive margins have highlighted the complexity of their architecture and their multi-stage deformation history. Previous modeling studies have shown the significant impact of coarse mechanical layering of the lithosphere (2 to 4 layer crust and mantle) on passive margin formation. We built upon these studies and design high-resolution (~100–300 m) thermo-mechanical numerical models that incorporate finer mechanical layering (kilometer scale) mimicking tectonically inherited heterogeneities. During lithospheric extension a variety of extensional structures arises naturally due to (1) structural softening caused by necking of mechanically strong layers and (2) the establishment of a network of weak layers across the deforming multi-layered lithosphere. We argue that structural softening in a multi-layered lithosphere is the main cause for the observed multi-stage evolution and architecture of magma-poor passive margins. PMID:27929057

Detailed facies analysis of the Upper Cretaceous Tununk Shale Member, Henry Mountains Region, Utah: Implications for mudstone depositional models in epicontinental seas

NASA Astrophysics Data System (ADS)

Li, Zhiyang; Schieber, Juergen

2018-02-01

Lower-Middle Turonian strata of the Tununk Shale Member of the greater Mancos Shale were deposited along the western margin of the Cretaceous Western Interior Seaway during the Greenhorn second-order sea level cycle. In order to examine depositional controls on facies development in this mudstone-rich succession, this study delineates temporal and spatial relationships in a process-sedimentologic-based approach. The 3-dimensional expression of mudstone facies associations and their stratal architecture is assessed through a fully integrative physical and biologic characterization as exposed in outcrops in south-central Utah. Sedimentologic characteristics from the millimeter- to kilometer-scale are documented in order to fully address the complex nature of sediment transport mechanisms observed in this shelf muddy environment. The resulting facies model developed from this characterization consists of a stack of four lithofacies packages including: 1) carbonate-bearing, silty and sandy mudstone (CSSM), 2) silt-bearing, calcareous mudstone (SCM), 3) carbonate-bearing, silty mudstone to muddy siltstone (CMS), and 4) non-calcareous, silty and sandy mudstone (SSM). Spatial and temporal variations in lithofacies type and sedimentary facies characteristics indicate that the depositional environments of the Tununk Shale shifted in response to the 2nd-order Greenhorn transgressive-regressive sea-level cycle. During this eustatic event, the Tununk shows a characteristic vertical shift from distal middle shelf to outer shelf (CSSM to SCM facies), then from outer shelf to inner shelf environment (SCM to CMS, and to SSM facies). Shifting depositional environments, as well as changes in dominant paleocurrent direction throughout this succession, indicate multiple source areas and transport mechanisms (i.e. longshore currents, offshore-directed underflows, storm reworking). This study provides a rare documentation of the Greenhorn cycle as exposed across the entire shelf setting. High-resolution mapping of genetically-related packages facilitate the development of process-based depositional models that can be utilized for lateral correlations into the equivalent foredeep strata of the Cretaceous Interior.

Sedimentological evidence for a deltaic origin of the western fan deposit in Jezero crater, Mars and implications for future exploration

NASA Astrophysics Data System (ADS)

Goudge, Timothy A.; Milliken, Ralph E.; Head, James W.; Mustard, John F.; Fassett, Caleb I.

2017-01-01

We examine the stratigraphic architecture and mineralogy of the western fan deposit in the Jezero crater paleolake on Mars to reassess whether this fan formed as a delta in a standing body of water, as opposed to by alluvial or debris flow processes. Analysis of topography and images reveals that the stratigraphically lowest layers within the fan have shallow dips (<2°), consistent with deltaic bottomsets, whereas overlying strata exhibit steeper dips (∼2-9°) and downlap, consistent with delta foresets. Strong clay mineral signatures (Fe/Mg-smectite) are identified in the inferred bottomsets, as would be expected in the distal fine-grained facies of a delta. We conclude that the Jezero crater western fan deposit is deltaic in origin based on the exposed stratal geometries and mineralogy, and we emphasize the importance of examining the stratigraphic architecture of sedimentary fan deposits on Mars to confidently distinguish between alluvial fans and deltas. Our results indicate that Jezero crater contains exceptionally well-preserved fluvio-deltaic stratigraphy, including strata interpreted as fine-grained deltaic bottomsets that would have had a high potential to concentrate and preserve organic matter. Future exploration of this site is both geologically and astrobiologically compelling, and in situ analyses would be complementary to the ongoing in situ characterization of fluvio-lacustrine sediment in the Gale crater paleolake basin by the Curiosity rover.

Statistics of Stacked Strata on Experimental Shelf Margins

NASA Astrophysics Data System (ADS)

Fernandes, A. M.; Straub, K. M.

2015-12-01

Continental margin deposits provide the most complete record on Earth of paleo-landscapes, but these records are complex and difficult to interpret. To a seismic geomorphologist or stratigrapher, mapped surfaces often present a static diachronous record of these landscapes through time. We present data that capture the dynamics of experimental shelf-margin landscapes at high-temporal resolution and define internal hierarchies within stacked channelized and weakly channelized deposits from the shelf to the slope. Motivated by observations from acoustically-imaged continental margins offshore Brunei and in the Gulf of Mexico, we use physical experiments to quantify stratal patterns of sub-aqueous slope channels and lobes that are linked to delta-top channels. The data presented here are from an experiment that was run for 26 hours of experimental run time. Overhead photographs and topographic scans captured flow dynamics and surface aggradation/degradation every ten minutes. Currents rich in sediment built a delta that prograded to the shelf-edge. These currents were designed to plunge at the shoreline and travel as turbidity currents beyond the delta and onto the continental slope. Pseudo-subsidence was imposed by a slight base-level rise that generated accommodation space and promoted the construction of stratigraphy on the delta-top. Compensational stacking is a term that is frequently applied to deposits that tend to fill in topographic lows in channelized and weakly channelized systems. The compensation index, a metric used to quantify the strength of compensation, is used here to characterize deposits at different temporal scales on the experimental landscape. The compensation timescale is the characteristic time at which the accumulated deposits begins to match the shape of basin-wide subsidence rates (uniform for these experiments). We will use the compensation indices along strike transects across the delta, proximal slope and distal slope to evaluate the degree of compensation and the trends in the compensation time-scale, tied to a reduced degree of channelization in the down-slope direction.

Impact of structural and autocyclic basin-floor topography on the depositional evolution of the deep-water Valparaiso forearc basin, central Chile

USGS Publications Warehouse

Laursen, J.; Normark, W.R.

2003-01-01

The Valparaiso Basin constitutes a unique and prominent deep-water forearc basin underlying a 40-km by 60-km mid-slope terrace at 2.5-km water depth on the central Chile margin. Seismic-reflection data, collected as part of the CONDOR investigation, image a 3-3.5-km thick sediment succession that fills a smoothly sagged, margin-parallel, elongated trough at the base of the upper slope. In response to underthrusting of the Juan Ferna??ndez Ridge on the Nazca plate, the basin fill is increasingly deformed in the seaward direction above seaward-vergent outer forearc compressional highs. Syn-depositional growth of a large, margin-parallel monoclinal high in conjunction with sagging of the inner trough of the basin created stratal geometries similar to those observed in forearc basins bordered by large accretionary prisms. Margin-parallel compressional ridges diverted turbidity currents along the basin axis and exerted a direct control on sediment depositional processes. As structural depressions became buried, transverse input from point sources on the adjacent upper slope formed complex fan systems with sediment waves characterising the overbank environment, common on many Pleistocene turbidite systems. Mass failure as a result of local topographic inversion formed a prominent mass-flow deposit, and ultimately resulted in canyon formation and hence a new focused point source feeding the basin. The Valparaiso Basin is presently filled to the spill point of the outer forearc highs, causing headward erosion of incipient canyons into the basin fill and allowing bypass of sediment to the Chile Trench. Age estimates that are constrained by subduction-related syn-depositional deformation of the upper 700-800m of the basin fill suggest that glacio-eustatic sea-level lowstands, in conjunction with accelerated denudation rates, within the past 350 ka may have contributed to the increase in simultaneously active point sources along the upper slope as well as an increased complexity of proximal depositional facies.

Regrounding in Place: Paths to Native American Truths at the Margins

ERIC Educational Resources Information Center

Lucas, Michael

2013-01-01

Margin acts as ground to receive the figure of the text. Margin is initially unreadable, but as suggested by gestalt studies, may be reversed, or regrounded. A humanities course, "Native American Architecture and Place," was created for a polytechnic student population, looking to place as an inroad for access to the margins of a better…

The Red Sea structural architecture assessment based on yield strength spatial variations and Arabian margin preexisting structures

NASA Astrophysics Data System (ADS)

Alotaibi, T.; Furlong, K. P.

2016-12-01

Rift initiation and localization might reflect spatial changes in the lithospheric yield strength. However, this does not appear to be the case in the Red Sea extensional system where fission track analysis shows no significant changes in the geothermal gradient prior to the Red Sea rift onset. In contrast, though the whole Red Sea rift initiated 25 Ma ago, its extensional architecture changes dramatically along strike from narrow localized spreading in the south to asymmetrical diffuse extension north of 21° latitude. This onset of diffuse extension has been recorded in the north-western Arabian margin as old as 33 Ma. Such diversity in the extensional style might reflect along strike yield strength variations as a consequence of the geological setting in the Arabian margin. The north-western Arabian basin, which is part of the Arabian margin, bounded by Qiba high from the east, the Arabian shield from the south and the west and Syrian plateau from the north. The basin accommodates part of the Red Sea diffuse extension and has a preexisting structural architecture represented in the Cenozoic failed rift that called Sarhan graben. Our goal is to analyze the current lithospheric yield strength spatial variations along the Red Sea rift and emphasize their relationship with the Arabian margin structural architecture. We hypothesize that the north-western Arabian margin's lithospheric weakness and structural diversity are playing an important role in producing region of diffuse extension by their interaction with the forces applied by far field stresses represented by the New Tethys slab pull. On the other hand, the south-western Arabian margin interacts with the far field stresses as a single strong block in which led to localize the extension in the southern Red Sea. Our work may improve the scientific community understanding for how rifts initiate and evolve over time.

The Messinian of the Nijar Basin (SE Spain): sedimentation, depositional environments and paleogeographic evolution

NASA Astrophysics Data System (ADS)

Fortuin, A. R.; Krijgsman, W.

2003-08-01

The reconstruction of the depositional events related to the Messinian Salinity Crisis (MSC) of the Mediterranean is generally hampered by an incomplete stratal record in the circum-Mediterranean basins. The sediments of the northern part of the Nijar Basin, however, provide an excellent and continuous record of Late Messinian sediments because features of severe erosion are lacking. Especially, the successions of the deeper part of the basin had sufficient accommodation space to warrant ongoing deposition and may thus serve as a testing ground for existing hypotheses regarding the MSC. Conformable contacts with the overlying Pliocene and good correlation possibilities with the adjacent, astronomically dated, Messinian of the Sorbas Basin provide the necessary age constraints. The main body of evaporites in the Nijar Basin (Yesares Formation) has been affected by local dissolution and erosion prior to deposition of the latest Messinian (Lago-Mare) facies. Pelitic float breccias show textures indicating flowage and/or mass transport and include slumped and slided stratal packets due to foundering of the mixed evaporitic-clastic margin. Increased runoff of meteoric waters probably played an important role as these packet slides are perfectly sealed by the hyposaline Lago-Mare strata. Field observations show that marginal sediments, commonly classified as the Terminal Carbonate Complex (TCC), are a lateral equivalent of the basinal Yesares evaporites. The latest Messinian deposits (Feos Formation) are characterized by a sedimentary cyclicity, related to fluctuating base levels, consisting of chalky-marly laminitic strata alternating with continental coarser clastic intervals. Despite considerable W-E facies changes and indications for discrete tectonic events, a persistent sequential pattern of eight Lago-Mare cycles is present, which are interpreted as precession-controlled variations in regional climate. Instead of one major desiccation event in the latest Messinian, the repeatedly fluctuating water levels of the Lago-Mare episode may have been the cause of the widespread vigorous erosion and canyon cutting in the "Lower Evaporites". Abrupt, non-erosional contacts with the normal marine Pliocene take place above the continental interval of the last Lago-Mare cycle, indicating that flooding took place during a period of lowered water levels. The paleogeographic configuration of the Nijar, Sorbas and Vera basins has changed considerably during the Messinian. Separation of the formerly interconnected basins is thought to have started in the late Yesares times by tectonic uplift of the basement complexes. In the latest Messinian of the Nijar Basin, two different coarse clastic supply areas can be distinguished which point to the partial emergence of the Sierra Cabrera and the Cabo de Gata block and activity of the Sierra Alhamilla and Carboneras faults. Concerning the overall regional tectonic activity, tectonics were probably also instrumental for the restoration of the Atlantic gateway in the basal Pliocene.

Design and "restoration": the Roots of Architecture Porject for the Built

NASA Astrophysics Data System (ADS)

Campanella, C.

2017-05-01

It is absolutely essential now to prepare a project of pre-critical understanding of the building which will be the object of action, free from preconceived notions of value, fully committed to the implementation of a variety of useful and indispensable to determine that operating margin and freedom that each architecture has not being linked uniquely to the precise original function. This is the margin that you can leverage to implement the architectural project for the built that mutuerà inside knowledge, conservation and innovation at the same time. The binomials in the lead paragraph as all sides of the same coin that merge into one integrated design process that takes charge of design including those different styles of drafting of survey (in all aspects) of an existing architecture.

Restoration of original 3D sedimentary geometries in deformed basin fill supporting reservoir characterization

NASA Astrophysics Data System (ADS)

Back, S.

2009-04-01

A large progradational clastic system centred on Brunei Darussalam has been present on the NW Borneo margin since the early middle Miocene. This system has many sedimentary and structural similarities with major deltaic provinces such as the Niger and Nile. It differs from these systems by being affected in the hinterland by contemporaneous compressional tectonics. Uplift partially forced strong progradation of the clastic system, but also folded older deltaic units. Erosion and the exhumation of folded strata in the area of the Jerudong Anticline resulted in the exposure of large-scale prograding clinoforms and syn-sedimentary deltaic faults of middle Miocene age along a natural cross-section of several tens of kilometres in extent. Westward of the key outcrop sites on the Jerudong Anticline, the middle Miocene deltaic units are overlain by late Miocene, Pliocene and Quaternary clastics up to 3 kilometres thick. Both, the middle Miocene target units of this study as well as the late Miocene to recent overburden are recorded in the subsurface of the Belait Syncline on regional 2D seismic lines (total line length around 1400 km) and at 7 well locations. In this study, we integrate the available geophysical subsurface information with existing structural, sedimentological and geomorphological field data of the "classic" Jerudong Anticline exposures (e.g., Back et al. 2001, Morley et al. 2003, Back et al. 2005) into a static 3D surface-subsurface model that provides quantitative constraints on the structural and stratigraphic architecture of the Miocene Belait delta and the overlying units in three dimensions, supporting basin-scale as well as reservoir-scale analysis of the subsurface rock volume. Additionally, we use the static surface-subsurface model as input for a tectonic retro-deformation of the study area, in which the 3D paleo-relief of the middle Miocene Belait delta is restored by unfolding and fault balancing (Back et al. 2008). This kinematic reconstruction ultimately provides a detailed view into the stratal architecture of middle Miocene delta clinoforms, indicating a close relationship between delta-lobe activity, clinoform morphology, and the generation of slumps and turbidites. Literature BACK, S., MORLEY, C.K., SIMMONS, M.D. & LAMBIASE, J.J. (2001): Depositional environment and sequence stratigraphy of Miocene deltaic cycles exposed along the Jerudong anticline, Brunei Darussalam. - Journal of Sedimentary Research, 71: 915-923. BACK, S., TIOE HAK JING, TRAN XUAN THANG & MORLEY, C.K. (2005): Stratigraphic development of synkinematic deposits in a large growth-fault system, onshore Brunei Darussalam. - Journal of the Geological Society, London, 162: 243-258. BACK, S., STROZYK, F., KUKLA, P.A. & LAMBIASE, J.J. (2008): 3D restoration of original sedimentary geometries in deformed basin fill, onshore Brunei Darussalam, NW Borneo. Basin Research, 20: 99-117. MORLEY, C.K., BACK, S., VANRENSBERGEN, P., CREVELLO, P. & LAMBIASE, J.J. (2003): Characteristics of repeated, detached, Miocene -Pliocene tectonic inversion events, in a large delta province on an active margin, Brunei Darussalam, Borneo. - Journal of Structural Geology, 25: 1147-1169.

Extensional collapse along the Sevier Desert reflection, northern Sevier Desert basin, western United States

NASA Astrophysics Data System (ADS)

Coogan, James C.; Decelles, Peter G.

1996-10-01

Newly released and previously published seismic reflection data from the northern Sevier Desert basin provide a complete seismic transect between the tilted western margin of the basin and the eastern breakaway zone. When tied to well and surface age data, the transect delineates a continuum of extensional fault and basin fill geometries that developed between late Oligocene and Pleistocene time across the basin. A minimum of 18 km of top-to-the-west normal displacement is estimated across the Sevier Desert from only the most conspicuous growth geometries and offsets across listric normal faults that sole downward into the Sevier Desert reflection (SDR). The SDR clearly marks a normal fault zone beneath the entire basin, where stratal truncations are imaged for 50% of the 39 km length of the reflection east of the Cricket Mountains block. Restoration of extensional displacement along this entire 39 km fault length is necessary to reconstruct the pre-Oligocene configuration and erosion level of Sevier thrust sheets across the Sevier Desert area. The SDR normal fault zone underlies the former topographic crest of the Sevier orogenic belt, where it accommodated extensional collapse after cessation of regional contractile tectonism.

Methane fluxes, microbes and carbonate mounds: insights from asin modelling of the porcupine basin, ireland

NASA Astrophysics Data System (ADS)

Naeth, J.; di Primio, R.; Schäfer, R. G.; Horsfield, B.

2003-04-01

Our broad task has been to investigate the origin and growth of large carbonate mounds within the Porcupine Basin offshore Ireland. Specifically, the project aims at determining the timing and magnitude of chemical degradation and physical redistribution processes which are likely to have played a key role in the formation of carbonate mounds. We addressed these issues using 2D basin modelling the results of which were used for map-based migration modelling. The overall sedimentary basin architecture of the basin facilitates up-dip fluid migration towards the western, eastern and especially the northern margins of the basin. Potential fluid migration pathways are available through a variety of stratal surfaces, unconformities, faults and detachments. The spatial association of deep water carbonate mounds with underlying fluid pathways is compatible with the provision of a basin-derived nutrient source (e.g. hydrocarbons). Numerical simulations lie at the centre of the investigation using three seismic lines covering the Hovland-Magellan mound area in the northern part of the basin and the Belgica mound area in the western part. The calibration of the thermal history was performed by iteratively using putative heat-flow scenarios in compliance with the known geologic evolution of the basin, present-day temperatures, organic maturity parameters, overpressure occurrence and assigned lithologies. After optimisation of the model, the generation and migration history of potential source units were modelled using, inter alia, the source richness and quality assignments referred to above and kinetic parameters of hydrocarbon generation determined experimentally. The results achieved indicate that: bullet hydrocarbon generation and expulsion is currently taking place in the vicinity of the mound locations bullet stratigraphic pinch outs and shallow structural closures underly most mounds bullet a high temporal and spatial resolution of the latest Tertiary and Quaternary events in combination with accurate paleo-water depth reconstructions are of critical importance for recognition of leakage pathways leading to the sea floor bullet the onset of carbonate mound growth coincides with the predicted timing of maximum thermogenic methane fluxes to the sea floor

Mass-transport deposits and reservoir quality of Upper Cretaceous Chalk within the German Central Graben, North Sea

NASA Astrophysics Data System (ADS)

Arfai, Jashar; Lutz, Rüdiger; Franke, Dieter; Gaedicke, Christoph; Kley, Jonas

2016-04-01

The architecture of intra-chalk deposits in the `Entenschnabel' area of the German North Sea is studied based on 3D seismic data. Adapted from seismic reflection characteristics, four types of mass-transport deposits (MTDs) are distinguished, i.e. slumps, slides, channels and frontal splay deposits. The development of these systems can be linked to inversion tectonics and halotectonic movements of Zechstein salt. Tectonic uplift is interpreted to have caused repeated tilting of the sea floor. This triggered large-scale slump deposition during Turonian-Santonian times. Slump deposits are characterised by chaotic reflection patterns interpreted to result from significant stratal distortion. The south-eastern study area is characterised by a large-scale frontal splay complex. This comprises a network of shallow channel systems arranged in a distributive pattern. Several slide complexes are observed near the Top Chalk in Maastrichtian and Danian sediments. These slides are commonly associated with large incisions into the sediments below. Best reservoir properties with high producible porosities are found in the reworked chalk strata, e.g. Danish North Sea, therefore MTDs detected in the study area are regarded as potential hydrocarbon reservoirs and considered as exploration targets.

Architecture of the Distal Piedmont-Ligurian Rifted Margin in NW Italy: Hints for a Flip of the Rift System Polarity

NASA Astrophysics Data System (ADS)

Decarlis, Alessandro; Beltrando, Marco; Manatschal, Gianreto; Ferrando, Simona; Carosi, Rodolfo

2017-11-01

The Alpine Tethys rifted margins were generated by a Mesozoic polyphase magma-poor rifting leading to the opening of the Piedmont-Ligurian "Ocean." This latter developed through different phases of rifting that terminated with the exhumation of subcontinental mantle along an extensional detachment system. At the onset of simple shear detachment faulting, two margin types were generated: an upper and a lower plate corresponding to the hanging wall and footwall of the final detachment system, respectively. The two margin architectures were markedly different and characterized by a specific asymmetry. In this study the detailed analysis of the Adriatic margin, exposed in the Serie dei Laghi, Ivrea-Verbano, and Canavese Zone, enabled to recognize the diagnostic elements of an upper plate rifted margin. This thesis contrasts with the classic interpretation of the Southalpine units, previously compared with the adjacent fossil margin preserved in the Austroalpine nappes and considered as part of a lower plate. The proposed scenario suggests the segmentation and flip of the Alpine rifting system along strike and the passage from a lower to an upper plate. Following this interpretation, the European and Southern Adria margins are coevally developed upper plate margins, respectively resting NE and SW of a major transform zone that accommodates a flip in the polarity of the rift system. This new explanation has important implications for the study of the pre-Alpine rift-related structures, for the comprehension of their role during the reactivation of the margin and for the paleogeographic evolution of the Alpine orogen.

Impact of longer-term modest climate shifts on architecture of high-frequency sequences (Cyclothems), Pennsylvanian of midcontinent U.S.A

USGS Publications Warehouse

Feldman, H.R.; Franseen, E.K.; Joeckel, R.M.; Heckel, P.H.

2005-01-01

Pennsylvanian glacioeustatic cyclothems exposed in Kansas and adjacent areas provide a unique opportunity to test models of the impact of relative sea level and climate on stratal architecture. A succession of eight of these high-frequency sequences, traced along dip for 500 km, reveal that modest climate shifts from relatively dry-seasonal to relatively wet-seasonal with a duration of several sequences (???600,000 to 1 million years) had a dominant impact on facies, sediment dispersal patterns, and sequence architecture. The climate shifts documented herein are intermediate, both in magnitude and duration, between previously documented longer-term climate shifts throughout much of the Pennsylvanian and shorter-term shifts described within individual sequences. Climate indicators are best preserved at sequence boundaries and in incised-valley fills of the lowstand systems tracts (LST). Relatively drier climate indicators include high-chroma paleosols, typically with pedogenic carbonates, and plant assemblages that are dominated by gymnosperms, mostly xerophytic walchian conifers. The associated valleys are small (4 km wide and >20 m deep), and dominated by quartz sandstones derived from distant source areas, reflecting large drainage networks. Transgressive systems tracts (TST) in all eight sequences gen erally are characterized by thin, extensive limestones and thin marine shales, suggesting that the dominant control on TST facies distribution was the sequestration of siliciclastic sediment in updip positions. Highstand systems tracts (HST) were significantly impacted by the intermediate-scale climate cycle in that HSTs from relatively drier climates consist of thin marine shales overlain by extensive, thick regressive limestones, whereas HSTs from relatively wetter climates are dominated by thick marine shales. Previously documented relative sea-level changes do not track the climate cycles, indicating that climate played a role distinct from that of relative sea-level change. These intermediate-scale modest climate shifts had a dominant impact on sequence architecture. This independent measure of climate and relative sea level may allow the testing of models of climate and sediment supply based on modern systems. Copyright ?? 2005, SEPM.

Seismic facies and stratigraphy of the Cenozoic succession in McMurdo Sound, Antarctica: Implications for tectonic, climatic and glacial history

USGS Publications Warehouse

Fielding, C.R.; Whittaker, J.; Henrys, S.A.; Wilson, T.J.; Nash, T.R.

2007-01-01

A new stratigraphic model is presented for the evolution of the Cenozoic Victoria Land Basin of the West Antarctic Rift, based on integration of seismic reflection and drilling data. The Early Rift phase (?latest Eocene to Early Oligocene) comprises wedges of strata confined by early extensional faults, and which contain seismic facies consistent with drainage via coarse-grained fans and deltas into discrete, actively subsiding grabens and half-grabens. The Main Rift phase (Early Oligocene to Early Miocene) comprises a lens of strata that thickens symmetrically from the basin margins into a central depocenter, and in which stratal events pass continuously over the top of the Early Rift extensional topography. Internal seismic facies and lithofacies indicate a more organized, cyclical shallow marine succession, influenced increasingly upward by cycles of glacial advance and retreat into the basin. The Passive Thermal Subsidence phase (Early Miocene to ?) comprises an evenly distributed sheet of strata that does not thicken appreciably into the depocentre, with more evidence for clinoform sets and large channels. These patterns are interpreted to record accumulation under similar environmental conditions but in a regime of slower subsidence. The Renewed Rifting phase (? to Recent, largely unsampled by coring thus far) has been further divided into 1, a lower interval, in which the section thickens passively towards a central depocentre, and 2. an upper interval, in which more dramatic thickening patterns are complicated by magmatic activity. The youngest part of the stratigraphy was accumulated under the influence of flexural loading imposed by the construction of large volcanic edifices, and involved minimal sediment supply from the western basin margin, suggesting a change in environmental (glacial) conditions at possibly c. 2 Ma.

New insights into North America-Pacific Plate boundary deformation from Lake Tahoe, Salton Sea and southern Baja California

NASA Astrophysics Data System (ADS)

Brothers, Daniel Stephen

Five studies along the Pacific-North America (PA-NA) plate boundary offer new insights into continental margin processes, the development of the PA-NA tectonic margin and regional earthquake hazards. This research is based on the collection and analysis of several new marine geophysical and geological datasets. Two studies used seismic CHIRP surveys and sediment coring in Fallen Leaf Lake (FLL) and Lake Tahoe to constrain tectonic and geomorphic processes in the lakes, but also the slip-rate and earthquake history along the West Tahoe-Dollar Point Fault. CHIRP profiles image vertically offset and folded strata that record deformation associated with the most recent event (MRE). Radiocarbon dating of organic material extracted from piston cores constrain the age of the MRE to be between 4.1--4.5 k.y. B.P. Offset of Tioga aged glacial deposits yield a slip rate of 0.4--0.8 mm/yr. An ancillary study in FLL determined that submerged, in situ pine trees that date to between 900-1250 AD are related to a medieval megadrought in the Lake Tahoe Basin. The timing and severity of this event match medieval megadroughts observed in the western United States and in Europe. CHIRP profiles acquired in the Salton Sea, California provide new insights into the processes that control pull-apart basin development and earthquake hazards along the southernmost San Andreas Fault. Differential subsidence (>10 mm/yr) in the southern sea suggests the existence of northwest-dipping basin-bounding faults near the southern shoreline. In contrast to previous models, the rapid subsidence and fault architecture observed in the southern part of the sea are consistent with experimental models for pull-apart basins. Geophysical surveys imaged more than 15 ˜N15°E oriented faults, some of which have produced up to 10 events in the last 2-3 kyr. Potentially 2 of the last 5 events on the southern San Andreas Fault (SAF) were synchronous with rupture on offshore faults, but it appears that ruptures on three offshore faults are synchronous with Colorado River diversions into the basin. The final study was used coincident wide-angle seismic refraction and multichannel seismic reflection surveys that spanned the width of the of the southern Baja California (BC) Peninsula. The data provide insight into the spatial and temporal evolution of the BC microplate capture by the Pacific Plate. Seismic reflection profiles constrain the upper crustal structure and deformation history along fault zone on the western Baja margin and in the Gulf of California. Stratal divergence in two transtensional basins along the Magdalena Shelf records the onset of extension across the Tosco-Abreojos and Santa Margarita faults. We define an upper bound of 12 Ma on the age of the pre-rift sediments and an age of ˜8 Ma for the onset of extension. Tomographic imaging reveals a very heterogeneous upper crust and a narrow, high velocity zone that extends ˜40 km east of the paleotrench and is interpreted to be remnant oceanic crust.

Lower crustal strength controls on melting and type of oceanization at magma-poor margins

NASA Astrophysics Data System (ADS)

Ros, E.; Perez-Gussinye, M.; Araujo, M. N.; Thoaldo Romeiro, M.; Andres-Martinez, M.; Morgan, J. P.

2017-12-01

Geodynamical models have been widely used to explain the variability in the architectonical style of conjugate rifted margins as a combination of lithospheric deformation modes, which are strongly influenced by lower crustal strength. We use 2D numerical models to show that the lower crustal strength also plays a key role on the onset and amount of melting and serpentinization during continental rifting. The relative timing between melting and serpentinization onsets controls whether the continent-ocean transition (COT) of margins will be predominantly magmatic or will mainly consist of exhumed and serpentinized mantle. Based on our results for magma-poor continental rifting, we propose a genetic link between margin architecture and COT styles that can be used as an additional tool to help interpret and understand the processes leading to margin formation. Our results show that strong lower crusts and very slow extension velocities (<5 mm/yr) lead to either symmetric or asymmetric margins with large oceanward dipping faults, strong syn-rift subsidence and abrupt crustal tapering beneath the continental shelf. These margins are characterized by a COT consisting of exhumed and serpentinized mantle and some magmatic products. Weak lower crusts at ultra-slow velocities lead also to either symmetric or asymmetric margins with small faults dipping both ocean- and landward, small syn-rift subsidence and gentle crustal tapering, and present a predominantly magmatic COT, perhaps underlain by some serpentinized mantle. When conjugate margins are asymmetric, if the rheology is relatively strong, serpentinite predominantly underlays the wide margin, whereas if the lower crustal strength is weak, melt preferentially migrates towards the wide margin. Based on the onshore lithospheric structure, extension velocity and margin architecture of the magma-poor section of the South Atlantic, we suggest that the COT of the northern sector, Camamu-Gabon basins, is more likely to consist of exhumed mantle with intruded magmatism, while to the South, the Camamu-Kwanza and North Santos-South Kwanza conjugates, may be better characterized by a predominantly magmatic COT.

Identifying and Interpreting Stratification in Sedimentary Rocks on Mars: Insight from Rover and Orbital Observations and Terrestrial Field Analogs

NASA Astrophysics Data System (ADS)

Edgar, Lauren A.

Sedimentary rocks on Mars provide insight into past aqueous and atmospheric processes, climate regimes, and potential habitability. The stratigraphic architecture of sedimentary rocks on Mars is similar to that of Earth, indicating that the processes that govern deposition and erosion on Mars can be reasonably inferred through reference to analogous terrestrial systems. This dissertation aims to understand Martian surface processes through the use of (1) ground-based observations from the Mars Exploration Rovers, (2) orbital data from the High Resolution Imaging Science Experiment onboard the Mars Reconnaissance Orbiter, and (3) the use of terrestrial field analogs to understand bedforms and sediment transport on Mars. Chapters 1 and 2 trace the history of aqueous activity at Meridiani Planum, through the reconstruction of eolian bedforms at Victoria crater, and the identification of a potential mudstone facies at Santa Maria crater. Chapter 3 uses Terrestrial Laser Scanning to study cross-bedding in pyroclastic surge deposits on Earth in order to understand sediment transport in these events and to establish criteria for their identification on Mars. The final chapter analyzes stratal geometries in the Martian North Polar Layered Deposits using tools for sequence stratigraphic analysis, to better constrain past surface processes and past climate conditions on Mars.

Venus orogenic belt environments - Architecture and origin

NASA Astrophysics Data System (ADS)

Head, James W.; Vorder Bruegge, Richard W.; Crumpler, L. S.

1990-08-01

Orogenic belt environments (Danu, Akna, Freyja, and Maxwell Montes) in Western Ishtar Terra, Venus, display a range of architectural elements, including (from the center of Western Ishtar outward) an inboard plateau (Lakshmi Planum), the linear orogenic belts themselves, outboard plateaus, steep scarps bounding Ishtar, adjacent linear foredeeps and outboard rises, and outboard low-lying volcanic plains. The main elements of the architecture are interpreted to be due to the convergence, underthrusting, and possible subduction of lowland plains at the margins of a preexisting tessera plateau of thicker crust.

Environmental and ice volume changes based on seismic stratigraphy in Sabrina Coast, East Antarctica: Preliminary results from NBP1402

NASA Astrophysics Data System (ADS)

Gulick, S. P. S.; Fernandez-Vasquez, R. A.; Frederick, B.; Saustrup, S., Sr.; Domack, E. W.; Lavoie, C.; Shevenell, A.; Blankenship, D. D.; Leventer, A.

2014-12-01

In 2014, the R/V Nathaniel B. Palmer (NBP1402) sailed to a virtually unexplored continental shelf along the Sabrina Coast, East Antarctica. The shelf contains the sedimentary record of environmental and ice volume changes within the Aurora Subglacial Basin (ASB), which is presently occupied by ~7 m sea level-rise equivalent of ice. We acquired 750 km of high-resolution seismic data proximal to the Reynolds Trough and Moscow University Ice Shelf glacial systems west of the Dalton Ice Tongue using dual 45/45 cu. in. G.I. guns and a 24 ch. streamer with 3.125 m groups providing a vertical resolution of ~3 m simultaneously with CHIRP data. These are the first images of this margin acquired and show a remarkable set of sequence stratigraphic transitions. Crystalline basement is at the seafloor landward and buried seaward with a transition to smoother reflection interface. Reflective sedimentary strata overlie the basement, dip seaward, and are capped by a landward-dipping regional angular unconformity. Above this are a series of transparent seismic facies that, along with the middle to outer shelf seafloor, dip landward towards a shelf-oblique glacial trough. The older, seaward-dipping strata include a deeper series of units that display at least three stratal architectures interpreted to be shelf deltas implying a pre-glacial, fluvial environment within the drainage basin. Above these sequences, the seismic facies transition to surfaces exhibiting significant erosion, small u-shaped valleys, and channel fill sequences, all of which are reminiscent of temperate glacial features. We interpret these sequences as including sub-ice tunnel valleys and grounding zone wedges with interspersed non-glacial to pro-glacial deposits. Increasing glaciogenic facies upsection suggests a gradual fluvial to glacial transition and increasing glacial extent with time. The subsequent transition to ice sheets is marked by erosion to basement landward and the angular unconformity seaward. The unconformity is overlain by glacial diamict, representing an incomplete record of cold-based glaciations after the ASB became ice-filled. Correlations with cores collected above and below the unconformity and deltaic unit should allow us to determine the ages of these transitions from fluvial to polythermal to ice sheets in East Antarctica.

In vivo architectural analysis of 3.2 mm clear corneal incisions for phacoemulsification using optical coherence tomography.

PubMed

Torres, Luis F; Saez-Espinola, Fidelia; Colina, Juner M; Retchkiman, Myriam; Patel, Milan R; Agurto, Ricardo; Garcia, Gerardo; Diaz, Jose L; Huang, David; Schanzlin, David J; Chayet, Arturo S

2006-11-01

To analyze in vivo the architecture of clear corneal incisions (CCIs) for phacoemulsification using optical coherence tomography (OCT). Anterior Segment Department, Asociacion Para Evitar la Ceguera en Mexico, Hospital Dr Luis Sanchez Bulnes, Mexico. A prospective masked study analyzed 20 unsutured CCIs placed superiorly and created in a uniplanar fashion with a 3.2 mm slit-angled metal keratome. All wounds were evaluated with a retinal OCT model 1, 3, and 30 days postoperatively. Intraocular pressure (IOP) and incision leakage were checked. The architecture was described according to the angle of incidence, apposition of the epithelial and endothelial margins, and wound sealing. No leakage was detected. The angle varied from 33 to 85 degrees; angles greater than 75 degrees were done by a surgeon in training. Wound apposition at the epithelial margin was achieved in all cases. In contrast, imperfect apposition of the endothelial margin was seen in 45% of incisions on day 1 and in 15% on day 30. Incomplete sealing of the wound was seen by OCT in 25% of cases at 24 hours and persisted in 10% of all cases at 1 month. This gaping occurred on the endothelial side and never translated to the epithelial margin. No statistical correlation was found between gaping and the angle of the incision, IOP variations, or surgeon experience. Although in vivo CCIs caused minor anatomic imperfections, they were clinically stable independent of incision angle, IOP variation, and surgeon experience. Incision stability may be related to careful wound construction, epithelial viability, stromal edema, and efficient endothelial pumping.

Monitoring of HIV viral load, CD4 cell count, and clinical assessment versus clinical monitoring alone for antiretroviral therapy in low-resource settings (Stratall ANRS 12110/ESTHER): a cost-effectiveness analysis.

PubMed

Boyer, Sylvie; March, Laura; Kouanfack, Charles; Laborde-Balen, Gabrièle; Marino, Patricia; Aghokeng, Avelin Fobang; Mpoudi-Ngole, Eitel; Koulla-Shiro, Sinata; Delaporte, Eric; Carrieri, Maria Patrizia; Spire, Bruno; Laurent, Christian; Moatti, Jean-Paul

2013-07-01

In low-income countries, the use of laboratory monitoring of patients taking antiretroviral therapy (ART) remains controversial in view of persistent resource constraints. The Stratall trial did not show that clinical monitoring alone was non-inferior to laboratory and clinical monitoring in terms of immunological recovery. We aimed to evaluate the costs and cost-effectiveness of the ART monitoring approaches assessed in the Stratall trial. The randomised, controlled, non-inferiority Stratall trial was done in a decentralised setting in Cameroon. Between May 23, 2006, and Jan 31, 2008, ART-naive adults were randomly assigned (1:1) to clinical monitoring (CLIN) or viral load and CD4 cell count plus clinical monitoring (LAB) and followed up for 24 months. We calculated costs, number of life-years saved (LYS), and incremental cost-effectiveness ratios (ICERs) with data from patients who had been followed up for at least 6 months. We considered two cost scenarios in which viral load plus CD4 cell count tests cost either US$95 (scenario 1; Abbott RealTime HIV-1 assay) or $63 (scenario 2; generic assay). We compared ICERs with a WHO-recommended threshold of three times the per-person gross domestic product (GDP) for Cameroon ($3670-3800) and an alternative lower threshold of $2385 to determine cost-effectiveness. We assessed uncertainty with one-way sensitivity analyses and cost-effectiveness acceptability curves. 188 participants who underwent LAB and 197 who underwent CLIN were followed up for at least 6 months. In scenario 1, LAB increased costs by a mean of $489 (SD 430) per patient and saved 0·103 life-years compared with CLIN (ICER of $4768 [95% CI 3926-5613] per LYS). In scenario 2, the incremental mean cost of LAB was $343 (SD 425) -ie, an ICER of $3339 (2507-4173) per LYS. A combined strategy in which LAB would only be used in patients starting ART with a CD4 count of 200 cells per μL or fewer suggests that 0·120 life-years would be saved at an additional cost of $259 per patient in scenario 1 (ICER of $2167 [95% CI 1314-3020] per LYS) and $181 in scenario 2 (ICER of $1510 [692-2329] per LYS) when compared with CLIN. Laboratory monitoring was not cost effective in 2006-10 compared with clinical monitoring when the Abbott RealTime HIV-1 assay was used according to the $3670 cost-effectiveness threshold (three times per-person GDP in Cameroon), but it might be cost effective if a generic in-house assay is used. French National Agency for Research on AIDS and Viral Hepatitis (ANRS) and Ensemble pour une Solidarité Thérapeutique Hospitalière En Réseau (ESTHER). Copyright © 2013 Elsevier Ltd. All rights reserved.

Glacial climate driven sedimentation overwhelms tectonics in the battle for control of margin architecture: Southeast Alaska, St. Elias Orogeny

NASA Astrophysics Data System (ADS)

Gulick, S. P.; Jaeger, J. M.; Willems, B.; Powell, R. D.; Lowe, L. A.

2006-12-01

The interplay of tectonic and climatic processes is fundamental to the development of mountain belts and the ensuing patterns of deformation and erosion. Of equal significance is the interaction of tectonic and climatic processes in the development of orogenic sedimentary basins, or in the case of a coastal mountain belt, in the growth of a continental margin. The Chugach-St. Elias Orogeny, which is driven by the collision of the Yakutat microplate with North America in southeast Alaska, has generated the highest coastal relief in the world. The combined forces of tectonic uplift and glacial erosion have resulted in the accumulation of over 5 km of sediment to form the continental shelf and the creation of the Surveyor Fan that is over 2 km thick proximally. High-resolution GI-gun seismic data allow for detailed examination of the margin architecture off the Bering Glacier within the leading edge of the Yakutat block. The deformation and growth of the margin appears to have first undergone a tectonically dominated phase followed more recently by a glacially dominated phase. During the tectonically dominated period a broad anticline-syncline system helped create accommodation space and the margin both shallowed and widened to its current 50 km width. Based on ties with industry well cuttings, the dominance switched sometime between 0.75 and 1.25 Ma to being completely controlled by glacial advance-retreat patterns. The mappable glacial sequences are undeformed by the underlying anticlines and display several notable features: 1) erosional bases that can often be mapped across the entire shelf, terminating at the shelf edge, 2) little evidence for terminal or retreat moraines on the shelf suggesting very rapid and single phase retreat of the glacier, 3) incomplete glacial sequences due to erosion by later advances, and 4) minimal creation of accommodation space. We investigate the cause of the switch to glacial dominance, the mechanisms and causes of the potentially extremely rapid glacial retreats, and the geodynamics of these glacial advances with respect to the development of margin architecture.

Geomorphology and till architecture of terrestrial palaeo-ice streams of the southwest Laurentide Ice Sheet: A borehole stratigraphic approach

NASA Astrophysics Data System (ADS)

Norris, Sophie L.; Evans, David J. A.; Cofaigh, Colm Ó.

2018-04-01

A multidimensional study, utilising geomorphological mapping and the analysis of regional borehole stratigraphy, is employed to elucidate the regional till architecture of terrestrial palaeo-ice streams relating to the Late Wisconsinan southwest Laurentide Ice Sheet. Detailed mapping over a 57,400 km2 area of southwestern Saskatchewan confirms previous reconstructions of a former southerly flowing ice stream, demarcated by a 800 km long corridor of megaflutes and mega-scale glacial lineations (Ice Stream 1) and cross cut by three, formerly southeast flowing ice streams (Ice Streams 2A, B and C). Analysis of the lithologic and geophysical characteristics of 197 borehole samples within these corridors reveals 17 stratigraphic units comprising multiple tills and associated stratified sediments overlying preglacial deposits, the till thicknesses varying with both topography and distance down corridor. Reconciling this regional till architecture with the surficial geomorphology reveals that surficial units are spatially consistent with a dynamic switch in flow direction, recorded by the cross cutting corridors of Ice Streams 1, 2A, B and C. The general thickening of tills towards lobate ice stream margins is consistent with subglacial deformation theory and variations in this pattern on a more localised scale are attributed to influences of subglacial topography including thickening at buried valley margins, thinning over uplands and thickening in overridden ice-marginal landforms.

An Integrated Hybrid Transportation Architecture for Human Mars Expeditions

NASA Technical Reports Server (NTRS)

Merrill, Raymond G.; Chai, Patrick R.; Qu, Min

2015-01-01

NASA's Human Spaceflight Architecture Team is developing a reusable hybrid transportation architecture that uses both chemical and electric propulsion systems on the same vehicle to send crew and cargo to Mars destinations such as Phobos, Deimos, the surface of Mars, and other orbits around Mars. By applying chemical and electrical propulsion where each is most effective, the hybrid architecture enables a series of Mars trajectories that are more fuel-efficient than an all chemical architecture without significant increases in flight times. This paper presents an integrated Hybrid in-space transportation architecture for piloted missions and delivery of cargo. A concept for a Mars campaign including orbital and Mars surface missions is described in detail including a system concept of operations and conceptual design. Specific constraints, margin, and pinch points are identified for the architecture and opportunities for critical path commercial and international collaboration are discussed.

Network-centric decision architecture for financial or 1/f data models

NASA Astrophysics Data System (ADS)

Jaenisch, Holger M.; Handley, James W.; Massey, Stoney; Case, Carl T.; Songy, Claude G.

2002-12-01

This paper presents a decision architecture algorithm for training neural equation based networks to make autonomous multi-goal oriented, multi-class decisions. These architectures make decisions based on their individual goals and draw from the same network centric feature set. Traditionally, these architectures are comprised of neural networks that offer marginal performance due to lack of convergence of the training set. We present an approach for autonomously extracting sample points as I/O exemplars for generation of multi-branch, multi-node decision architectures populated by adaptively derived neural equations. To test the robustness of this architecture, open source data sets in the form of financial time series were used, requiring a three-class decision space analogous to the lethal, non-lethal, and clutter discrimination problem. This algorithm and the results of its application are presented here.

Sedimentary architecture of a Plio-Pleistocene proto-back-arc basin: Wanganui Basin, New Zealand

NASA Astrophysics Data System (ADS)

Proust, Jean-Noël; Lamarche, Geoffroy; Nodder, Scott; Kamp, Peter J. J.

2005-11-01

The sedimentary architecture of active margin basins, including back-arc basins, is known only from a few end-members that barely illustrate the natural diversity of such basins. Documenting more of these basins types is the key to refining our understanding of the tectonic evolution of continental margins. This paper documents the sedimentary architecture of an incipient back-arc basin 200 km behind the active Hikurangi subduction margin, North Island, New Zealand. The Wanganui Basin (WB) is a rapidly subsiding, Plio-Pleistocene sedimentary basin located at the southern termination of the extensional back-arc basin of the active Central Volcanic Region (TVZ). The WB is asymmetric with a steep, thrust-faulted, outer (arc-ward) margin and a gentle inner (craton-ward) margin. It contains a 4-km-thick succession of Plio-Pleistocene sediments, mostly lying offshore, composed of shelf platform sediments. It lacks the late molasse-like deposits derived from erosion of a subaerial volcanic arc and basement observed in classical back-arc basins. Detailed seismic stratigraphic interpretations from an extensive offshore seismic reflection data grid show that the sediment fill comprises two basin-scale mega-sequences: (1) a Pliocene (3.8 to 1.35 Ma), sub-parallel, regressive "pre-growth" sequence that overtops the uplifted craton-ward margin above the reverse Taranaki Fault, and (2) a Pleistocene (1.35 Ma to present), divergent, transgressive, "syn-growth" sequence that onlaps: (i) the craton-ward high to the west, and (ii) uplifted basement blocks associated with the high-angle reverse faults of the arc-ward margin to the east. Along strike, the sediments offlap first progressively southward (mega-sequence 1) and then southeastward (mega-sequence 2), with sediment transport funnelled between the craton- and arc-ward highs, towards the Hikurangi Trough through the Cook Strait. The change in offlap direction corresponds to the onset of arc-ward thrust faulting and the rise of the Axial Ranges at ca 1.75 Ma, resulting in 5100-5700 m of differential subsidence across the fault system. Sedimentation has propagated south- to southeast-ward over the last 4 Myrs at the tip of successive back-arc graben, volcanic arcs and the associated thermally uplifted parts of the North Island, following the southward migration of the Hikurangi subduction margin. Subsidence occurred by mantle flow-driven flexure, the result of active down-drag of the lithosphere by locking of the Hikurangi subduction interface and sediment loading. The WB is considered to be a proto-back-arc basin that represents the intermediate stage of evolution of an epicratonic shelf platform, impacted by active margin processes.

Advanced Control Considerations for Turbofan Engine Design

NASA Technical Reports Server (NTRS)

Connolly, Joseph W.; Csank, Jeffrey T.; Chicatelli, Amy

2016-01-01

This paper covers the application of a model-based engine control (MBEC) methodology featuring a self tuning on-board model for an aircraft turbofan engine simulation. The nonlinear engine model is capable of modeling realistic engine performance, allowing for a verification of the advanced control methodology over a wide range of operating points and life cycle conditions. The on-board model is a piece-wise linear model derived from the nonlinear engine model and updated using an optimal tuner Kalman Filter estimation routine, which enables the on-board model to self-tune to account for engine performance variations. MBEC is used here to show how advanced control architectures can improve efficiency during the design phase of a turbofan engine by reducing conservative operability margins. The operability margins that can be reduced, such as stall margin, can expand the engine design space and offer potential for efficiency improvements. Application of MBEC architecture to a nonlinear engine simulation is shown to reduce the thrust specific fuel consumption by approximately 1% over the baseline design, while maintaining safe operation of the engine across the flight envelope.

Crustal-Scale Fault Interaction at Rifted Margins and the Formation of Domain-Bounding Breakaway Complexes: Insights From Offshore Norway

NASA Astrophysics Data System (ADS)

Osmundsen, P. T.; Péron-Pinvidic, G.

2018-03-01

The large-magnitude faults that control crustal thinning and excision at rifted margins combine into laterally persistent structural boundaries that separate margin domains of contrasting morphology and structure. We term them breakaway complexes. At the Mid-Norwegian margin, we identify five principal breakaway complexes that separate the proximal, necking, distal, and outer margin domains. Downdip and lateral interactions between the faults that constitute breakaway complexes became fundamental to the evolution of the 3-D margin architecture. Different types of fault interaction are observed along and between these faults, but simple models for fault growth will not fully describe their evolution. These structures operate on the crustal scale, cut large thicknesses of heterogeneously layered lithosphere, and facilitate fundamental margin processes such as deformation coupling and exhumation. Variations in large-magnitude fault geometry, erosional footwall incision, and subsequent differential subsidence along the main breakaway complexes likely record the variable efficiency of these processes.

System Architecture of Small Unmanned Aerial System for Flight Beyond Visual Line-of-Sight

DTIC Science & Technology

2015-09-17

Signal Strength PT = Transmitter Power GT = Transmitter antenna gain LT = Transmitter loss Lp = Propagation loss GR = Receiver antenna...gain (dBi) LR(db) = Receiver losses (dB) 15 Lm = Link margin (dB) PT = Transmitter Power (dBm) GT = Transmitter antenna gain (dBi) LT... Transmitter loss (dB) The maximum range is determined by four components, 1) Transmission, 2) Propagation, 3) Reception and 4) Link Margin

Prediction of HIV drug resistance based on virologic, immunologic, clinical, and/or adherence criteria in the Stratall ANRS 12110/ESTHER trial in Cameroon.

PubMed

Boullé, Charlotte; Kouanfack, Charles; Laborde-Balen, Gabrièle; Aghokeng, Avelin Fobang; Boyer, Sylvie; Carrieri, Maria Patrizia; Kazé, Serge; Mben, Jean-Marc; Dontsop, Marlise; Spire, Bruno; Peeters, Martine; Mpoudi-Ngolé, Eitel; Delaporte, Eric; Laurent, Christian

2013-08-01

Our study in Cameroonian rural district hospitals showed that the immunologic and clinical failure criteria had poor performance to identify human immunodeficiency virus drug resistance in a timely manner. Switching to second-line antiretroviral therapy after 2 consecutive viral loads ≥5000 copies/mL, as recommended by the World Health Organization, appeared to be the most appropriate strategy.

Using crustal thickness and subsidence history on the Iberia-Newfoundland margins to constrain lithosphere deformation modes during continental breakup

NASA Astrophysics Data System (ADS)

Jeanniot, Ludovic; Kusznir, Nick; Manatschal, Gianreto; Mohn, Geoffroy

2014-05-01

Observations at magma-poor rifted margins such as Iberia-Newfoundland show a complex lithosphere deformation history during continental breakup and seafloor spreading initiation leading to complex OCT architecture with hyper-extended continental crust and lithosphere, exhumed mantle and scattered embryonic oceanic crust and continental slivers. Initiation of seafloor spreading requires both the rupture of the continental crust and lithospheric mantle, and the onset of decompressional melting. Their relative timing controls when mantle exhumation may occur; the presence or absence of exhumed mantle provides useful information on the timing of these events and constraints on lithosphere deformation modes. A single lithosphere deformation mode leading to continental breakup and sea-floor spreading cannot explain observations. We have determined the sequence of lithosphere deformation events for two profiles across the present-day conjugate Iberia-Newfoundland margins, using forward modelling of continental breakup and seafloor spreading initiation calibrated against observations of crustal basement thickness and subsidence. Flow fields, representing a sequence of lithosphere deformation modes, are generated by a 2D finite element viscous flow model (FeMargin), and used to advect lithosphere and asthenosphere temperature and material. FeMargin is kinematically driven by divergent deformation in the upper 15-20 km of the lithosphere inducing passive upwelling beneath that layer; extensional faulting and magmatic intrusions deform the topmost upper lithosphere, consistent with observations of deformation processes occurring at slow spreading ocean ridges (Cannat, 1996). Buoyancy enhanced upwelling, as predicted by Braun et al. (2000) is also kinematically included in the lithosphere deformation model. Melt generation by decompressional melting is predicted using the parameterization and methodology of Katz et al. (2003). The distribution of lithosphere deformation, the contribution of buoyancy driven upwelling and their spatial and temporal evolution including lateral migration are determined by using a series of numerical experiments, tested and calibrated against observations of crustal thicknesses and water-loaded subsidence. Pure-shear widths exert a strong control on the timing of crustal rupture and melt initiation; to satisfy OCT architecture, subsidence and mantle exhumation, we need to focus the deformation from a broad to a narrow region. The lateral migration of the deformation flow axis has an important control on the rupture of continental crust and lithosphere, melt initiation, their relative timing, the resulting OCT architecture and conjugate margin asymmetry. The numerical models are used to predict margin isostatic response and subsidence history.

Mesozoic carbonate-siliciclastic platform to basin systems of a South Tethyan margin (Egypt, East Mediterranean)

NASA Astrophysics Data System (ADS)

Tassy, Aurélie; Crouzy, Emmanuel; Gorini, Christian; Rubino, Jean-Loup

2015-04-01

The Mesozoïc Egyptian margin is the south margin of a remnant of the Neo-Tethys Ocean, at the African northern plate boundary. East Mediterranean basin developed during the late Triassic-Early Jurassic rifting with a NW-SE opening direction (Frizon de Lamotte et al., 2011). During Mesozoïc, Egypt margin was a transform margin with a NW-SE orientation of transform faults. In the Eastern Mediterranean basin, Mesozoïc margins are characterized by mixed carbonate-siliciclastics platforms where subsidence and eustacy are the main parameters controlling the facies distribution and geometries of the platform-to-basin transition. Geometries and facies on the platform-slope-basin system, today well constrained on the Levant area, where still poorly known on the Egyptian margin. Geometries and stratigraphic architecture of the Egyptian margin are revealed, thanks to a regional seismic and well data-base provided by an industrial-academic group (GRI, Total). The objective is to understand the sismostratigraphic architecture of the platform-slope-basin system in a key area from Western Desert to Nile delta and Levant margin. Mapping of the top Jurassic and top Cretaceous show seismic geomorphology of the margin, with the cartography of the hinge line from Western Desert to Sinaï. During the Jurassic, carbonate platform show a prograding profile and a distally thickening of the external platform, non-abrupt slope profiles, and palaeovalleys incisions. Since the Cretaceous, the aggrading and retrograding mixed carbonate-siliciclastic platform show an alternation of steep NW-SE oblique segments and distally steepened segments. These structures of the platform edge are strongly controlled by the inherited tethyan transform directions. Along the hinge line, embayments are interpreted as megaslides. The basin infilling is characterised by an alternation of chaotic seismic facies and high amplitude reflectors onlaping the paleoslopes. MTC deposits can mobilize thick sedimentary series (up to 3500 m) as a mixed combination of debris flows, internal preserved blocks, and/or compressively-deformed distal allochthonous masses. Transported material have proceeded from the dismantling of the Mesozoic mixed carbonate-siliciclastic platform. They can spread down slope over areas as large as 70000 of km2. According to stratigraphic correlations with global sea-level positions, platform instability would have been triggered by the gravitational collapse of the carbonate-siliciclastic platform under its own weight after successive subaerial exposures which were able to generate karstification processes. Seismic interpretation is constrained by a detailed assessment of the Egyptian margin paleogeography supported by wells. This margin segment is briefly compared to the outcropping Apulian margin in Italy.

How does the connectivity of open-framework conglomerates within multi-scale hierarchical fluvial architecture affect oil-sweep efficiency in waterflooding?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gershenzon, Naum I.; Soltanian, Mohamad Reza; Ritzi, Robert W.

Understanding multi-phase fluid flow and transport processes within aquifers, candidate reservoirs for CO 2 sequestration, and petroleum reservoirs requires understanding a diverse set of geologic properties of the aquifer or reservoir, over a wide range of spatial and temporal scales. We focus on multiphase flow dynamics with wetting (e.g., water) and non-wetting (e.g., gas or oil) fluids, with one invading another. This problem is of general interest in a number of fields and is illustrated here by considering the sweep efficiency of oil during a waterflood. Using a relatively fine-resolution grid throughout a relatively large domain in these simulations andmore » probing the results with advanced scientific visualization tools (Reservoir Visualization Analysis [RVA]/ ParaView software) promote a better understanding of how smaller-scale features affect the aggregate behavior at larger scales. We studied the effects on oil-sweep efficiency of the proportion, hierarchical organization, and connectivity of high-permeability open-framework conglomerate (OFC) cross-sets within the multi-scale stratal architecture found in fluvial deposits. We further analyzed oil production rate, water breakthrough time, and spatial and temporal distribution of residual oil saturation. As expected, the effective permeability of the reservoir exhibits large-scale anisotropy created by the organization of OFC cross-sets within unit bars, and the organization of unit bars within compound- bars. As a result, oil-sweep efficiency critically depends on the direction of the pressure gradient. However, contrary to expectations, the total amount of trapped oil due to the effect of capillary trapping does not depend on the magnitude of the pressure gradient within the examined range. Hence the pressure difference between production and injection wells does not affect sweep efficiency; although the spatial distribution of oil remaining in the reservoir depends on this value. Whether or not clusters of connected OFC span the domain affects only the absolute rate of oil production—not sweep efficiency.« less

How does the connectivity of open-framework conglomerates within multi-scale hierarchical fluvial architecture affect oil-sweep efficiency in waterflooding?

DOE PAGES

Gershenzon, Naum I.; Soltanian, Mohamad Reza; Ritzi, Robert W.; ...

2015-10-23

Understanding multi-phase fluid flow and transport processes within aquifers, candidate reservoirs for CO 2 sequestration, and petroleum reservoirs requires understanding a diverse set of geologic properties of the aquifer or reservoir, over a wide range of spatial and temporal scales. We focus on multiphase flow dynamics with wetting (e.g., water) and non-wetting (e.g., gas or oil) fluids, with one invading another. This problem is of general interest in a number of fields and is illustrated here by considering the sweep efficiency of oil during a waterflood. Using a relatively fine-resolution grid throughout a relatively large domain in these simulations andmore » probing the results with advanced scientific visualization tools (Reservoir Visualization Analysis [RVA]/ ParaView software) promote a better understanding of how smaller-scale features affect the aggregate behavior at larger scales. We studied the effects on oil-sweep efficiency of the proportion, hierarchical organization, and connectivity of high-permeability open-framework conglomerate (OFC) cross-sets within the multi-scale stratal architecture found in fluvial deposits. We further analyzed oil production rate, water breakthrough time, and spatial and temporal distribution of residual oil saturation. As expected, the effective permeability of the reservoir exhibits large-scale anisotropy created by the organization of OFC cross-sets within unit bars, and the organization of unit bars within compound- bars. As a result, oil-sweep efficiency critically depends on the direction of the pressure gradient. However, contrary to expectations, the total amount of trapped oil due to the effect of capillary trapping does not depend on the magnitude of the pressure gradient within the examined range. Hence the pressure difference between production and injection wells does not affect sweep efficiency; although the spatial distribution of oil remaining in the reservoir depends on this value. Whether or not clusters of connected OFC span the domain affects only the absolute rate of oil production—not sweep efficiency.« less

Architecture and Channel-Belt Clustering in the Fluvial lower Wasatch Formation, Uinta Basin, Utah

NASA Astrophysics Data System (ADS)

Pisel, J. R.; Pyles, D. R.; Bracken, B.; Rosenbaum, C. D.

2013-12-01

The Eocene lower Wasatch Formation of the Uinta Basin contains exceptional outcrops of low net-sand content (27% sand) fluvial strata. This study quantitatively documents the stratigraphy of a 7 km wide by 300 meter thick strike-oriented outcrop in order to develop a quantitative data base that can be used to improve our knowledge of how some fluvial systems evolve over geologic time scales. Data used to document the outcrop are: (1) 550 meters of decimeter to half meter scale resolution stratigraphic columns that document grain size and physical sedimentary structures; (2) detailed photopanels used to document architectural style and lithofacies types in the outcrop; (3) thickness, width, and spatial position for all channel belts in the outcrop, and (4) directional measurements of paleocurrent indicators. Two channel-belt styles are recognized: lateral and downstream accreting channel belts; both of which occur as either single or multi-story. Floodplain strata are well exposed and consist of overbank fines and sand-rich crevasse splay deposits. Key upward and lateral characteristics of the outcrop documented herein are the following. First, the shapes of 243 channels are documented. The average width, thickness and aspect ratios of the channel belts are 110 m, 7 m, and 16:1, respectively. Importantly, the size and shape of channel belts does not change upward through the 300 meter transect. Second, channels are documented to spatially cluster. 9 clusters are documented using a spatial statistic. Key upward patterns in channel belt clustering are a marked change from non-amalgamated isolated channel-belt clusters to amalgamated channel-belt clusters. Critically, stratal surfaces can be correlated from mudstone units within the clusters to time-equivalent floodplain strata adjacent to the cluster demonstrating that clusters are not confined within fluvial valleys. Finally, proportions of floodplain and channel belt elements underlying clusters and channel belts vary with the style of clusters and channel belts laterally and vertically within the outcrop.

Sedimentology and architecture of De Geer moraines in the western Scottish Highlands, and implications for grounding-line glacier dynamics

NASA Astrophysics Data System (ADS)

Golledge, Nicholas R.; Phillips, Emrys

2008-07-01

Sedimentary exposures in moraines in a Scottish Highland valley (Glen Chaorach), reveal stacked sequences of bedded and laminated silt, sand and gravel, interspersed or capped with diamicton units. In four examples, faults and folds indicate deformation by glaciotectonism and syndepositional loading. We propose that these sediments were laid down in an ice-dammed lake, close to the last ice margin to occupy this glen. Individual units within cross-valley De Geer moraine ridges are interpreted by comparison with examples from similar environments elsewhere: stratified diamictons containing laminated or bedded lenses are interpreted as subaqueous ice-marginal debris-flow deposits; massive fine-grained deposits as hyperconcentrated flow deposits, and massive gravel units as high-density debris-flow deposits. Using an allostratigraphic approach we argue that glaciotectonically deformed coarsening-upward sand and gravel sequences that culminate in deposition of subglacial diamicton represent glacier advances into the ice-marginal lake, whereas undisturbed cross-bedded sand and gravel reflects channel or fan deposits laid down during glacier retreat. A flat terrace of bedded sand and gravel at the northern end of Glen Chaorach is interpreted as subaerial glaciofluvial outwash. On the basis of these inferences we propose the following three stage deglacial event chronology for Glen Chaorach. During glacier recession, ice separation and intra-lobe ponding first led to subaquaeous deposition of sorted and unsorted facies. Subsequent glacier stabilisation and ice-marginal oscillation produced glaciotectonic structures in the ice-marginal sediment pile and formed De Geer moraines. Finally, drainage of the ice-dammed lake allowed a subaerial ice-marginal drainage system to become established. Throughout deglaciation, deposition within the lake was characterized by abrupt changes in grain size and in the architecture of individual sediment bodies, reflecting changing delivery paths and sediment supply, and by dynamic margin oscillations typical of water-terminating glaciers.

Biofacies expression of Upper Cretaceous sequences in the Rock Springs uplift

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Y.Y.; Pflum, C.E.; Wright, R.C.

1991-03-01

The sequence-stratigraphic framework and vertical succession of depositional environments in the Upper Cretaceous section of the Rock Springs uplift is expressed in the biofacies patterns as well as in the stratal stacking patterns. Vertical trends in six biofacies parameters track affinities to marine and nonmarine environments as well as proximity to the paleoshoreline. These six parameters and their environmental significance include the relative proportion of herbaceous kerogen (land-derived), amorphous kerogen (marine), dinoflagellates (marine), bisaccate pollen (land-derived but buoyant and easily transported offshore), and the abundance and diversity of benthic foraminifera (both increase offshore). Shoaling marine environments are characterized by anmore » increasing proportion of herbaceous kerogen and decreasing proportions of amorphous kerogen, dinoflagellated, bisaccates, and the abundance and diversity of benthic foraminifera. Conversely, a deepening-upward marine sedimentary succession is characterized by an opposite trend in these parameters. A synthesis of the six biofacies parameters emphasizes the third-order cyclicity of the stratal succession as reflected in the well-developed third-order downlap surfaces and condensed sections. The biofacies trends indicate the transgressive nature of the lower Rock Springs and lower Lewis formations, and the progradational nature of the upper arts of the Baxter, Blair, and Rock Springs formations. An overall progradational (i.e., shoaling) character is exhibited in the three lower sequences (Baxter through Rock Springs) by the progressively decreasing abundance of amorphous kerogen, dinoflagellates, and foraminifera.« less

Thinning of heterogeneous lithosphere: insights from field observations and numerical modelling

NASA Astrophysics Data System (ADS)

Petri, B.; Duretz, T.; Mohn, G.; Schmalholz, S. M.

2017-12-01

The nature and mechanisms of formation of extremely thinned continental crust (< 10 km) and lithosphere during rifting remain debated. Observations from present-day and fossil continental passive margins document the heterogeneous nature of the lithosphere characterized, among others, by lithological variations and structural inheritance. This contribution aims at investigating the mechanisms of extreme lithospheric thinning by exploring in particular the role of initial heterogeneities by coupling field observations from fossil passive margins and numerical models of lithospheric extension. Two field examples from the Alpine Tethys margins outcropping in the Eastern Alps (E Switzerland and N Italy) and in the Southern Alps (N Italy) were selected for their exceptional level of preservation of rift-related structures. This situation enables us to characterize (1) the pre-rift architecture of the continental lithosphere, (2) the localization of rift-related deformation in distinct portion of the lithosphere and (3) the interaction between initial heterogeneities of the lithosphere and rift-related structures. In a second stage, these observations are integrated in high-resolution, two-dimensional thermo-mechanical models taking into account various patterns of initial mechanical heterogeneities. Our results show the importance of initial pre-rift architecture of the continental lithosphere during rifting. Key roles are given to high-angle and low-angle normal faults, anastomosing shear-zones and decoupling horizons. We propose that during the first stages of thinning, deformation is strongly controlled by the complex pre-rift architecture of the lithosphere, localized along major structures responsible for the lateral extrusion of mid to lower crustal levels. This extrusion juxtaposes mechanically stronger levels in the hyper-thinned continental crust, being exhumed by subsequent low-angle normal faults. Altogether, these results highlight the critical role of the extraction of mechanically strong layers of the lithosphere during the extreme thinning of the continental lithosphere and allows to propose a new model for the formation of continental passive margins.

Source facies and oil families of the Malay Basin, Malaysia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Creaney, S.; Hussein, A.H.; Curry, D.J.

1994-07-01

The Malay Basin consists of a number of separate petroleum systems, driven exclusively by nonmarine source rocks. These systems range from lower Oligocene to middle Miocene and show a progression from lacustrine-dominated source facies in the lower Oligocene to lower Miocene section to coastal plain/delta plain coal-related sources in the lower to middle Miocene section. Two lacustrine sources are recognized in the older section, and multiple source/reservoir pairs are recognized in the younger coaly section. The lacustrine sources can be recognized using well-log analysis combined with detailed core and sidewall core sampling. Chemically, they are characterized by low pristane/phytane ratios,more » low oleanane contents, and a general absence of resin-derived terpanes. These sources have TOCs in the 1.0-4.0% range and hydrogen indices of up to 750. In contrast, the coal-related sources are chemically distinct with pristane/phytane ratios of up to 8, very high oleanane contents, and often abundant resinous compounds. All these sources are generally overmature in the basin center and immature toward the basin margin. The oils sourced from all sources in the Malay Basin are generally low in sulfur and of very high economic value. Detailed biomarker analysis of the oils in the Malay Basin has allowed the recognition of families associated with the above sources and demonstrated that oil migration has been largely strata parallel with little cross-stratal mixing of families.« less

GBU-X bounding requirements for highly flexible munitions

NASA Astrophysics Data System (ADS)

Bagby, Patrick T.; Shaver, Jonathan; White, Reed; Cafarelli, Sergio; Hébert, Anthony J.

2017-04-01

This paper will present the results of an investigation into requirements for existing software and hardware solutions for open digital communication architectures that support weapon subsystem integration. The underlying requirements of such a communication architecture would be to achieve the lowest latency possible at a reasonable cost point with respect to the mission objective of the weapon. The determination of the latency requirements of the open architecture software and hardware were derived through the use of control system and stability margins analyses. Studies were performed on the throughput and latency of different existing communication transport methods. The two architectures that were tested in this study include Data Distribution Service (DDS) and Modular Open Network Architecture (MONARCH). This paper defines what levels of latency can be achieved with current technology and how this capability may translate to future weapons. The requirements moving forward within communications solutions are discussed.

Glacial morphology and depositional sequences of the Antarctic Continental Shelf

USGS Publications Warehouse

ten Brink, Uri S.; Schneider, Christopher

1995-01-01

Proposes a simple model for the unusual depositional sequences and morphology of the Antarctic continental shelf. It considers the regional stratal geometry and the reversed morphology to be principally the results of time-integrated effects of glacial erosion and sedimentation related to the location of the ice grounding line. The model offers several guidelines for stratigraphic interpretation of the Antarctic shelf and a Northern Hemisphere shelf, both of which were subject to many glacial advances and retreats. -Authors

Mesozoic architecture of a tract of the European-Iberian continental margin: Insights from preserved submarine palaeotopography in the Longobucco Basin (Calabria, Southern Italy)

NASA Astrophysics Data System (ADS)

Santantonio, Massimo; Fabbi, Simone; Aldega, Luca

2016-01-01

The sedimentary successions exposed in northeast Calabria document the Jurassic-Early Cretaceous tectonic-sedimentary evolution of a former segment of the European-Iberian continental margin. They are juxtaposed today to units representing the deformation of the African and Adriatic plates margins as a product of Apenninic crustal shortening. A complex pattern of unconformities reveals a multi-stage tectonic evolution during the Early Jurassic, which affected the facies and geometries of siliciclastic and carbonate successions deposited in syn- and post-rift environments ranging from fluvial to deep marine. Late Sinemurian/Early Pliensbachian normal faulting resulted in exposure of the Hercynian basement at the sea-floor, which was onlapped by marine basin-fill units. Shallow-water carbonate aprons and reefs developed in response to the production of new accommodation space, fringing the newborn islands which represent structural highs made of Paleozoic crystalline and metamorphic rock. Their drowning and fragmentation in the Toarcian led to the development of thin caps of Rosso Ammonitico facies. Coeval to these deposits, a thick (> 1 km) hemipelagic/siliciclastic succession was sedimented in neighboring hanging wall basins, which would ultimately merge with the structural high successions. Footwall blocks of the Early Jurassic rift, made of Paleozoic basement and basin-margin border faults with their onlapping basin-fill formations, are found today at the hanging wall of Miocene thrusts, overlying younger (Middle/Late Jurassic to Late Paleogene) folded basinal sediments. This paper makes use of selected case examples to describe the richly diverse set of features, ranging from paleontology to sedimentology, to structural geology, which are associated with the field identification of basin-margin unconformities. Our data provide key constraints for restoring the pre-orogenic architecture of a continental margin facing a branch of the Liguria-Piedmont ocean in the Western Tethys, and for estimating displacements and slip rates along synsedimentary faults.

Neoproterozoic fragmentation of the Scottish Sector of Laurentia - an ancient analogue for the Iberian and UK/Irish ocean-continent transition zones

NASA Astrophysics Data System (ADS)

Leslie, G.; Krabbendam, M.

2009-04-01

The Neoproterozoic Dalradian Supergroup of Scotland and Ireland is intensively deformed and metamorphosed by mid-Ordovician arc-accretion (c. 460 Ma) during the Caledonian Orogeny. Emplacement of an extensive suite of Siluro-Devonian Caledonian granitoids further complicates reading the sedimentary record. Nevertheless we can determine a history of stretching and break-up affecting the Neoproterozoic supercontinent of Rodinia and leading to creation of the Iapetus Ocean. Three key intervals of late-Neoproterozoic sediment accumulation are recognised - new geological mapping, isotopic datasets (Sr, O and C, U/Pb zircon, Sm/Nd WR), and sequence stratigraphical approaches are refining constraints on the lithostratigraphical architecture and basin evolution of the Dalradian Supergroup. Thick siliciclastic deposits accumulated (pre-800 Ma?) during an early stretching phase (distributed high angle faulting) that led to crustal thinning (low angle shearing). Three major limestone - pelite - quartzite depositional cycles succeeded these earlier siliciclastic deposits, recording episodic subsidence in an intracratonic but largely marine environment; the second cycle overlaps the late Precambrian (Cryogenian) glaciation and concludes with the distinctive Marinoan tillite succession (c. 635Ma). The last of the three cycles is terminated, in some parts of the Dalradian, by deposition of serpentinitic muds and conglomerates and volcaniclastic sediments; pods and lenses of both massive and serpentinised ultramafic rock also interrupt the sedimentary record at this level (thus possibly indicating mantle exhumation). In other areas, a major part of the ‘type' Dalradian succession is absent and we now recognise a major overstep unconformity at this level. From this level onwards across the Dalradian, rapid foundering of the margin, and the transition from rift- to drift-dominated processes, resulted in an overstepping accumulation of laterally and vertically variable, increasingly immature clastic sediments and volcanic rocks. Within 30-40 Ma of the end of Marinoan glaciation, an Iapetan oceanic rift was generating MORB rocks in a localised 600 my old (proto-) rift in the SW part of the Grampian Terrane. Rapid foundering thus pre-dated the first appearance of MORB basalts. Turbidite deposition then persisted after this first emergence of oceanic rocks until the early-Ordovician when convergence began to record arc-accretion and collision. During rift-drift transition, continental fragments apparently separated from the passive margin; the architecture of the Scotland-Greenland sector of Laurentia possibly resembled the present-day configuration of troughs and highs on the UK/Irish sector of the Atlantic continental shelf. Marginal plateaux analogous to the Rockall platform would have been separated from the intact continental margin by sub-basins analogous to the Rockall Trough. Such features would have channelled sediment outboard of, and along, the new passive margin in submarine fan systems. The extensional geometries of the various components of this architecture exerted control on the collisional geometry and acted as nuclei for deformation structures during Grampian orogenesis. Compound collisions in the mid-Ordovician stacked much of the original continental fragments into the complex pattern observed today. The challenge is thus to see through that later deformation and read the record of continental separation. There is much in the depositional architecture of the Dalradian Supergroup that suggests that a magma-poor passive margin is a viable model for this sector of the Laurentian margin.

How does continental lithosphere break-apart? A 3D seismic view on the transition from magma-poor rifted margin to magmatic oceanic lithosphere

NASA Astrophysics Data System (ADS)

Emmanuel, M.; Lescanne, M.; Picazo, S.; Tomasi, S.

2017-12-01

In the last decade, high-quality seismic data and drilling results drastically challenged our ideas about how continents break apart. New models address their observed variability and are presently redefining basics of rifting as well as exploration potential along deepwater rifted margins. Seafloor spreading is even more constrained by decades of scientific exploration along Mid Oceanic Ridges. By contrast, the transition between rifting and drifting remains a debated subject. This lithospheric breakup "event" is geologically recorded along Ocean-Continent Transitions (OCT) at the most distal part of margins before indubitable oceanic crust. Often lying along ultra-deepwater margin domains and buried beneath a thick sedimentary pile, high-quality images of these domains are rare but mandatory to get strong insights on the processes responsible for lithospheric break up and what are the consequences for the overlying basins. We intend to answer these questions by studying a world-class 3D seismic survey in a segment of a rifted margin exposed in the Atlantic. Through these data, we can show in details the OCT architecture between a magma-poor hyper-extended margin (with exhumed mantle) and a classical layered oceanic crust. It is characterized by 1- the development of out-of-sequence detachment systems with a landward-dipping geometry and 2- the increasing magmatic additions oceanwards (intrusives and extrusives). Geometry of these faults suggests that they may be decoupled at a mantle brittle-ductile interface what may be an indicator on thermicity. Furthermore, magmatism increases as deformation migrates to the future first indubitable oceanic crust what controls a progressive magmatic crustal thickening below, above and across a tapering rest of margin. As the magmatic budget increases oceanwards, full-rate divergence is less and less accommodated by faulting. Magmatic-sedimentary architectures of OCT is therefore changing from supra-detachment to magmatic oceanic half-grabens (low-crustal extension, high magma additions) and to ultimate layered oceanic crust (quasi-none crustal extension, full magmatic accretion). All of these elements suggest that lithospheric breakup can be addressed as a tectonic-magma competition as the brittle-ductile mantle interface is shallowing along OCT.

Initial Evaluations of LoC Prediction Algorithms Using the NASA Vertical Motion Simulator

NASA Technical Reports Server (NTRS)

Krishnakumar, Kalmanje; Stepanyan, Vahram; Barlow, Jonathan; Hardy, Gordon; Dorais, Greg; Poolla, Chaitanya; Reardon, Scott; Soloway, Donald

2014-01-01

Flying near the edge of the safe operating envelope is an inherently unsafe proposition. Edge of the envelope here implies that small changes or disturbances in system state or system dynamics can take the system out of the safe envelope in a short time and could result in loss-of-control events. This study evaluated approaches to predicting loss-of-control safety margins as the aircraft gets closer to the edge of the safe operating envelope. The goal of the approach is to provide the pilot aural, visual, and tactile cues focused on maintaining the pilot's control action within predicted loss-of-control boundaries. Our predictive architecture combines quantitative loss-of-control boundaries, an adaptive prediction method to estimate in real-time Markov model parameters and associated stability margins, and a real-time data-based predictive control margins estimation algorithm. The combined architecture is applied to a nonlinear transport class aircraft. Evaluations of various feedback cues using both test and commercial pilots in the NASA Ames Vertical Motion-base Simulator (VMS) were conducted in the summer of 2013. The paper presents results of this evaluation focused on effectiveness of these approaches and the cues in preventing the pilots from entering a loss-of-control event.

On the use of statistical methods to interpret electrical resistivity data from the Eumsung basin (Cretaceous), Korea

NASA Astrophysics Data System (ADS)

Kim, Ji-Soo; Han, Soo-Hyung; Ryang, Woo-Hun

2001-12-01

Electrical resistivity mapping was conducted to delineate boundaries and architecture of the Eumsung Basin Cretaceous. Basin boundaries are effectively clarified in electrical dipole-dipole resistivity sections as high-resistivity contrast bands. High resistivities most likely originate from the basement of Jurassic granite and Precambrian gneiss, contrasting with the lower resistivities from infilled sedimentary rocks. The electrical properties of basin-margin boundaries are compatible with the results of vertical electrical soundings and very-low-frequency electromagnetic surveys. A statistical analysis of the resistivity sections is tested in terms of standard deviation and is found to be an effective scheme for the subsurface reconstruction of basin architecture as well as the surface demarcation of basin-margin faults and brittle fracture zones, characterized by much higher standard deviation. Pseudo three-dimensional architecture of the basin is delineated by integrating the composite resistivity structure information from two cross-basin E-W magnetotelluric lines and dipole-dipole resistivity lines. Based on statistical analysis, the maximum depth of the basin varies from about 1 km in the northern part to 3 km or more in the middle part. This strong variation supports the view that the basin experienced pull-apart opening with rapid subsidence of the central blocks and asymmetric cross-basinal extension.

Shelf architectures of an isolated Late Cretaceous carbonate platform margin, Galala Mountains (Eastern Desert, Egypt)

NASA Astrophysics Data System (ADS)

Scheibner, C.; Marzouk, A. M.; Kuss, J.

2001-12-01

An asymmetrical carbonate platform margin to basin transect has been investigated in the Upper Campanian-Maastrichtian succession of the Galala Mountains, northern Egypt. Identification of systems tracts and their lateral correlation was possible in slope sections only, whereas the monotonous chalk-marl alternations of the basinal sections could not be subdivided with respect to sequence stratigraphic terminology. The platform asymmetry is expressed by varying large-scale depositional architectures exhibiting a rimmed platform with a sigmoidal slope curvature in south-easterly dip-sections and a ramp with a linear slope curvature in south-westerly dip-sections. The rimmed platform is subdivided into a gentle upper slope and a steep lower slope. The platform formed as a result of the initial topography that was controlled by the tectonic uplift of the Northern Galala/Wadi Araba Syrian Arc structure. The calculated angles of the steep lower slope of the rimmed part range from 5 to 8°, whereas the ramp part has an angle of less than 0.1°.

Asymmetry and polarity of the South Atlantic conjugated margins related to the presence of cratons: a numerical study

NASA Astrophysics Data System (ADS)

Andrés-Martínez, Miguel; Pérez-Gussinyé, Marta; de Monserrat Navarro, Albert; Morgan, Jason P.

2015-04-01

Tectonic asymmetry of conjugated passive margins, where one margin is much narrower than the conjugate one, is commonly observed at many passive margins world-wide. Conjugate margin asymmetry has been suggested to be a consequence of lateral changes in rheology, composition, temperature gradient or geometries of the crust and lithosphere. Here we use the South Atlantic margins (from Camamu/Gabon to North Santos/South Kwanza) as a natural laboratory to understand conjugate margin asymmetry. Along this margin sector the polarity of the asymmetry changes. To the North, the Brazilian margin developed in the strong Sao Francisco craton, and this constitutes the narrow side of the conjugate pair. To the South, the Brazilian margin developed in the Ribeira fold belt, and the margin is wide. The opposite is true for the African side. We have thus numerically analysed how the relative distance between the initial location of extension and the craton influences the symmetry/asymmetry and polarity of the conjugate margin system. Our numerical model is 2D visco-elasto-plastic and has a free surface, strain weakening and shear heating. The initial set-up includes a cratonic domain, a mobile belt and a transition area between both. We have run tests with different rheologies, thickness of the lithosphere, and weak seeds at different distances from the craton. Results show asymmetric conjugated margins, where the narrower margin is generally the closest to the craton. Our models also allow us to study how the polarity is controlled by the distance between the initial weakness and the craton, and help to understand how the presence of cratonic domains affects the final architecture of the conjugated margins.

Avionic Architecture for Model Predictive Control Application in Mars Sample & Return Rendezvous Scenario

NASA Astrophysics Data System (ADS)

Saponara, M.; Tramutola, A.; Creten, P.; Hardy, J.; Philippe, C.

2013-08-01

Optimization-based control techniques such as Model Predictive Control (MPC) are considered extremely attractive for space rendezvous, proximity operations and capture applications that require high level of autonomy, optimal path planning and dynamic safety margins. Such control techniques require high-performance computational needs for solving large optimization problems. The development and implementation in a flight representative avionic architecture of a MPC based Guidance, Navigation and Control system has been investigated in the ESA R&T study “On-line Reconfiguration Control System and Avionics Architecture” (ORCSAT) of the Aurora programme. The paper presents the baseline HW and SW avionic architectures, and verification test results obtained with a customised RASTA spacecraft avionics development platform from Aeroflex Gaisler.

Early evolution of the southern margin of the Neuquén Basin, Argentina: Tectono-stratigraphic implications for rift evolution and exploration of hydrocarbon plays

NASA Astrophysics Data System (ADS)

D'Elia, Leandro; Bilmes, Andrés; Franzese, Juan R.; Veiga, Gonzalo D.; Hernández, Mariano; Muravchik, Martín

2015-12-01

Long-lived rift basins are characterized by a complex structural and tectonic evolution. They present significant lateral and vertical stratigraphic variations that determine diverse basin-patterns at different timing, scale and location. These issues cause difficulties to establish facies models, correlations and stratal stacking patterns of the fault-related stratigraphy, specially when exploration of hydrocarbon plays proceeds on the subsurface of a basin. The present case study corresponds to the rift-successions of the Neuquén Basin. This basin formed in response to continental extension that took place at the western margin of Gondwana during the Late Triassic-Early Jurassic. A tectono-stratigraphic analysis of the initial successions of the southern part of the Neuquén Basin was carried out. Three syn-rift sequences were determined. These syn-rift sequences were located in different extensional depocentres during the rifting phases. The specific periods of rifting show distinctly different structural and stratigraphic styles: from non-volcanic to volcanic successions and/or from continental to marine sedimentation. The results were compared with surface and subsurface interpretations performed for other depocentres of the basin, devising an integrated rifting scheme for the whole basin. The more accepted tectono-stratigraphic scheme that assumes the deposits of the first marine transgression (Cuyo Cycle) as indicative of the onset of a post-rift phase is reconsidered. In the southern part of the basin, the marine deposits (lower Cuyo Cycle) were integrated into the syn-rift phase, implying the existence of different tectonic signatures for Cuyo Cycle along the basin. The rift climax becomes younger from north to south along the basin. The post-rift initiation followed the diachronic ending of the main syn-rift phase throughout the Neuquén Basin. Thus, initiation of the post-rift stage started in the north and proceeded towards the south, constituting a diachronous post-rift event. This arrangement implies that the lower part of Cuyo Cycle, traditionally related to regional thermal subsidence, may be deposited during either mechanical subsidence or thermal subsidence according to its position within the basin.

Folding and fracturing of rock adjacent to salt diapirs

NASA Astrophysics Data System (ADS)

Rowan, Mark G.

2017-04-01

When John Ramsay wrote his groundbreaking book in 1967, deformation around salt diapirs was not something he covered. At the time, most geologists considered diapirs to form due to density inversion, rising through thick overlying strata due to buoyancy. In doing so, salt was thought to shove aside the younger rocks, shearing and fracturing them in drag folds and supposedly producing "salt gouge". Even after it was realized that the majority of diapirs spend most of their history growing at or just beneath the surface, the relative rise of salt and sinking of minibasins were (and are) still thought by many to be accommodated in part by shear and fracturing of rocks in a collar zone around the salt. There are two arguments against this model. The first is mechanical: whereas halite behaves as a viscous fluid, even young sediment deforms as a brittle material with layer anisotropy. Thus, the salt-sediment interface is the outer margin of an intrasalt shear zone caused by viscous drag against the diapir margin. The velocity of salt flow decreases dramatically toward the edge of the diapir, so that the outermost salt effectively doesn't move. Hence, no shear or fracturing is expected in surrounding strata. The second and more important argument is that empirical field data do not support the idea of drag folds and associated deformation. Certainly, strata are typically folded and thinned adjacent to diapirs. However, stratal upturn is generated by monoclinal drape folding of the diapir roof over the edge of the rising salt, and thinning is caused by deposition onto the bathymetric highs formed by the diapirs, often supplemented by roof erosion and slumping. Halokinetic sequences observed in numerous salt basins (e.g., Paradox Basin, La Popa Basin, Spanish Pyrenees, Sivas Basin, Zagros Mountains, Kuqa Basin) contain no diapir-parallel shear zones and minimal thinning and fracturing caused by diapir rise. Even megaflaps, in which strata extend for kilometers up the sides of diapirs, have very little internal deformation. Instead, what faults are present around diapirs are related to drape folding (radial and diapir-parallel faults) or regional tectonics (extensional, contractional, strike-slip, and salt-evacuation faults).

The crustal structure and tectonic development of the continental margin of the Amundsen Sea Embayment, West Antarctica: implications from geophysical data

NASA Astrophysics Data System (ADS)

Kalberg, Thomas; Gohl, Karsten

2014-07-01

The Amundsen Sea Embayment of West Antarctica represents a key component in the tectonic history of Antarctic-New Zealand continental breakup. The region played a major role in the plate-kinematic development of the southern Pacific from the inferred collision of the Hikurangi Plateau with the Gondwana subduction margin at approximately 110-100 Ma to the evolution of the West Antarctic Rift System. However, little is known about the crustal architecture and the tectonic processes creating the embayment. During two `RV Polarstern' expeditions in 2006 and 2010 a large geophysical data set was collected consisting of seismic-refraction and reflection data, ship-borne gravity and helicopter-borne magnetic measurements. Two P-wave velocity-depth models based on forward traveltime modelling of nine ocean bottom hydrophone recordings provide an insight into the lithospheric structure beneath the Amundsen Sea Embayment. Seismic-reflection data image the sedimentary architecture and the top-of-basement. The seismic data provide constraints for 2-D gravity modelling, which supports and complements P-wave modelling. Our final model shows 10-14-km-thick stretched continental crust at the continental rise that thickens to as much as 28 km beneath the inner shelf. The homogenous crustal architecture of the continental rise, including horst and graben structures are interpreted as indicating that wide-mode rifting affected the entire region. We observe a high-velocity layer of variable thickness beneath the margin and related it, contrary to other `normal volcanic type margins', to a proposed magma flow along the base of the crust from beneath eastern Marie Byrd Land-West Antarctica to the Marie Byrd Seamount province. Furthermore, we discuss the possibility of upper mantle serpentinization by seawater penetration at the Marie Byrd Seamount province. Hints of seaward-dipping reflectors indicate some degree of volcanism in the area after break-up. A set of gravity anomaly data indicate several phases of fully developed and failed rift systems, including a possible branch of the West Antarctic Rift System in the Amundsen Sea Embayment.

"Suicide Heights": Council Estates as Sites of Entrapment and Resistance in "Hello Mum"

ERIC Educational Resources Information Center

Toplu, Sebnem

2014-01-01

Council estates have been contestable social spaces of contemporary urban life in metropolitan cities like London and the marginalizing spatial experience they provide for the "working class" has been a problematic topic for many disciplines like architecture, sociology, psychology and literature. Considering the significance of space…

Combatting Marginalized Spaces in Education through Language Architecture

ERIC Educational Resources Information Center

Flores, Nelson

2016-01-01

In this commentary, Flores states that language policing traps language-minoritized students in the position of having to reject their home language practices as inferior to the language practices of schooling. Language-minoritized students who are unable or unwilling to conform to these expectations, says Flores, are placed in the solitary…

Exploration of operator method digital optical computers for application to NASA

NASA Technical Reports Server (NTRS)

1990-01-01

Digital optical computer design has been focused primarily towards parallel (single point-to-point interconnection) implementation. This architecture is compared to currently developing VHSIC systems. Using demonstrated multichannel acousto-optic devices, a figure of merit can be formulated. The focus is on a figure of merit termed Gate Interconnect Bandwidth Product (GIBP). Conventional parallel optical digital computer architecture demonstrates only marginal competitiveness at best when compared to projected semiconductor implements. Global, analog global, quasi-digital, and full digital interconnects are briefly examined as alternative to parallel digital computer architecture. Digital optical computing is becoming a very tough competitor to semiconductor technology since it can support a very high degree of three dimensional interconnect density and high degrees of Fan-In without capacitive loading effects at very low power consumption levels.

Feedbacks Between Surface Processes and Tectonics at Rifted Margins: a Numerical Approach

NASA Astrophysics Data System (ADS)

Andres-Martinez, M.; Perez-Gussinye, M.; Morgan, J. P.; Armitage, J. J.

2014-12-01

Mantle dynamics drives the rifting of the continents and consequent crustal processes shape the topography of the rifted margins. Surface processes modify the topography by eroding positive reliefs and sedimenting on the basins. This lateral displacement of masses implies a change in the loads during rifting, affecting the architecture of the resulting margins. Furthermore, thermal insulation due to sediments could potentially have an impact on the rheologies, which are proved to be one of the most influential parameters that control the deformation style at the continental margins. In order to understand the feedback between these processes we have developed a numerical geodynamic model based on MILAMIN. Our model consists of a 2D Lagrangian triangular mesh for which velocities, displacements, pressures and temperatures are calculated each time step. The model is visco-elastic and includes a free-surface stabilization algorithm, strain weakening and an erosion/sedimentation algorithm. Sediment loads and temperatures on the sediments are taken into account when solving velocities and temperatures for the whole model. Although surface processes are strongly three-dimensional, we have chosen to study a 2D section parallel to the extension as a first approach. Results show that where sedimentation occurs strain further localizes. This is due to the extra load of the sediments exerting a gravitational force over the topography. We also observed angular unconformities on the sediments due to the rotation of crustal blocks associated with normal faults. In order to illustrate the feedbacks between surface and inner processes we will show a series of models calculated with different rheologies and extension velocities, with and without erosion/sedimentation. We will then discuss to which extent thermal insulation due to sedimentation and increased stresses due to sediment loading affect the geometry and distribution of faulting, the rheology of the lower crust and consequently margin architecture.

Control of hyper-extended passive margin architecture on subduction initiation with application to the Alps and present-day North Atlantic ocean

NASA Astrophysics Data System (ADS)

Candioti, Lorenzo; Bauville, Arthur; Picazo, Suzanne; Mohn, Geoffroy; Kaus, Boris

2016-04-01

Hyper-extended magma-poor margins are characterized by extremely thinned crust and partially serpentinized mantle exhumation. As this can act as a zone of weakness during a subsequent compression event, a hyper-extended margin can thus potentially facilitate subduction initiation. Hyper-extended margins are also found today as passive margins fringing the Atlantic and North Atlantic ocean, e.g. Iberia and New Foundland margins [1] and Porcupine, Rockwall and Hatton basins. It has been proposed in the literature that hyper-extension in the Alpine Tethys does not exceed ~600 km in width [2]. The geodynamical evolution of the Alpine and Atlantic passive margins are distinct: no subduction is yet initiated in the North Atlantic, whereas the Alpine Tethys basin has undergone subduction. Here, we investigate the control of the presence of a hyper-extended margin on subduction initiation. We perform high resolution 2D simulations considering realistic rheologies and temperature profiles for these locations. We systematically vary the length and thickness of the hyper-extended crust and serpentinized mantle, to better understand the conditions for subduction initiation. References: [1] G. Manatschal. New models for evolution of magma-poor rifted margins based on a review of data and concepts from West Iberia and the Alps. Int J Earth Sci (Geol Rundsch) (2004); 432-466. [2] G. Mohn, G. Manatschal, M. Beltrando, I. Haupert. The role of rift-inherited hyper-extension in alpine-type orogens. Terra Nova (2014); 347-353.

Integration of borehole and seismic data to unravel complex stratigraphy: Case studies from the Mannville Group, Western Canada

NASA Astrophysics Data System (ADS)

Sarzalejo Silva, Sabrina Ester

Understanding the stratigraphic architecture of geologically complex reservoirs, such as the heavy oil deposits of Western Canada, is essential to achieve an efficient hydrocarbon recovery. Borehole and 3-D seismic data were integrated to define the stratigraphic architecture and generate 3-dimensional geological models of the Mannville Group in Saskatchewan. The Mannville is a stratigraphically complex unit formed of fluvial to marine deposits. Two areas in west-central and southern Saskatchewan were examined in this study. In west-central Saskatchewan, the area corresponds to a stratigraphically controlled heavy oil reservoir with production from the undifferentiated Dina-Cummings Members of the Lower Cretaceous Mannville Group. The southern area, although non-prospective for hydrocarbons, shares many similarities with time-equivalent strata in areas of heavy oil production. Seismic sequence stratigraphic principles together with log signatures permitted the subdivision of the Mannville into different packages. An initial geological model was generated integrating seismic and well-log data Multiattribute analysis and neural networks were used to generate a pseudo-lithology or gamma-ray volume. The incorporation of borehole core data to the model and the subsequent integration with the lithological prediction were crucial to capture the distribution of reservoir and non-reservoir deposits in the study area. The ability to visualize the 3-D seismic data in a variety of ways, including arbitrary lines and stratal or horizon slicing techniques helped the definition of stratigraphic features such as channels and scroll bars that affect fluid flow in hydrocarbon producing areas. Small-scale heterogeneities in the reservoir were not resolved due to the resolution of the seismic data. Although not undertaken in this study, the resulting stratigraphic framework could be used to help construct a static reservoir model. Because of the small size of the 3-D seismic surveys, horizontal slices through the data volume generally imaged only small portions of the paleogeomorphologic features thought to be present in this area. As such, it was only through the integration of datasets that the geological models were established.

Comparison of CO2 trapping in highly heterogeneous reservoirs with Brooks-Corey and van Genuchten capillary pressure curves

NASA Astrophysics Data System (ADS)

Gershenzon, Naum; Soltanian, Mohamadreza; Ritzi, Robert, Jr.; Dominic, David

2015-04-01

Geological heterogeneities essentially affect the dynamics of a CO2 plume in subsurface environments. Recent studies have led to new conceptual and quantitative models for sedimentary architecture in fluvial deposits over a range of scales that are relevant to the performance of some deep saline reservoirs [1, 2]. Previously we showed how the dynamics of a CO2 plume, during and after injection, is influenced by the hierarchical and multi-scale stratal architecture in such reservoirs [3]. The results strongly suggest that representing these small scales (few cm in vertical direction and few meters in horizontal direction) features and representing how they are organized within a hierarchy of larger-scale features, is critical to understanding capillary trapping processes. The results also demonstrated the importance of using separate capillary pressure and relative permeability relationships for different textural facies types. Here we present the result of simulation of CO2 trapping in deep saline aquifers using two different conventional approaches, i.e. Brooks-Corey and van Genuchten, to capillary pressure. We showed that capillary trapping as well as dissolution rates are very different for the Brooks-Corey and van Genuchten approaches if reservoir consists from various species with different capillary pressure and relative permeability curves. We also found a dramatic difference in simulation time; using the van Genuchten approach improves convergence and thus reduces calculation time by one-two orders of magnitude. [1] Bridge, J.S. (2006), Fluvial facies models: Recent developments, in Facies Models Revisited, SEPM Spec. Publ., 84, edited by H. W. Posamentier and R. G. Walker, pp. 85-170, Soc. for Sediment. Geol. (SEPM), Tulsa, Okla [2] Ramanathan, R., A. Guin, R.W. Ritzi, D.F. Dominic, V.L. Freedman, T.D. Scheibe, and I.A. Lunt (2010), Simulating the heterogeneity in channel belt deposits: Part 1. A geometric-based methodology and code, Water Resources Research, v. 46, W04515. [3] Gershenzon N.I., M. Soltanian, R.W. Ritzi Jr., and D.F. Dominic (2014) Influence of small scale heterogeneity on CO2 trapping processes in deep saline aquifers, Energy Procedia, 59, 166 - 173.

Discriminating Sediment Supply versus Accommodation Controls on Late Cretaceous Foreland Basin Stratigraphic Architecture in the Book Cliffs, Utah using Detrital Zircon Double Dating

NASA Astrophysics Data System (ADS)

Bartschi, N.; Saylor, J. E.

2016-12-01

Middle to late Campanian strata of the Book Cliffs, Utah record the Late Cretaceous deposition of three clastic wedges in the North American Cordilleran foreland basin east of the Sevier thrust-belt. Variations in wedge geometries provide an opportunity to evaluate the effects of sediment supply versus accommodation on foreland basin stratal architecture. There is a significant increase in eastward progradation rate from the Lower to the Upper Castlegate Sandstone. However, the progradation rate decreases in the overlying Bluecastle and Price River formations, as well as the laterally equivalent Farrer and Tuscher formations. Rapid progradation during Upper Castlegate deposition may be caused by increased sediment supply from either rapid exhumation of the Sevier thrust-belt or introduction of a new sediment source. Alternatively, reduced accommodation within the proximal foreland basin from uplifts associated with Laramide deformation, or a transition from flexural to dynamic subsidence, could produce the observed rapid wedge progradation. Changes in sediment provenance and source-area exhumation rate can be identified using a combination of detrital zircon U-Pb geochronology and (U-Th)/He thermochronology. Quantitative comparisons between collected samples and published provenance data indicates an upsection increase in a new sediment source, revealing a significant overall shift in provenance between wedge boundaries. This change in provenance is coupled by an upsection decrease in lag time between the Lower and Upper Castlegate, consistent with an increase in exhumation rate. Conversely, there is no change in lag time between the Upper Castlegate and overlying Price River Formation, suggesting a relatively constant exhumation rate. Near-zero lag times during the Upper Castlegate is consistent with rapid exhumation associated with increased thrusting of the Sevier thrust-belt. Therefore, progradation of the Upper Castlegate can be attributed to an increase in sediment supply due to both rapid exhumation of the Sevier thrust-belt and introduction of a new sediment source. However, the data do not rule out the potential influence of reduced accommodation associated with early Laramide deformation during Upper Castlegate deposition.

Overcoming the drawback of lower sense margin in tunnel FET based dynamic memory along with enhanced charge retention and scalability

NASA Astrophysics Data System (ADS)

Navlakha, Nupur; Kranti, Abhinav

2017-11-01

The work reports on the use of a planar tri-gate tunnel field effect transistor (TFET) to operate as dynamic memory at 85 °C with an enhanced sense margin (SM). Two symmetric gates (G1) aligned to the source at a partial region of intrinsic film result into better electrostatic control that regulates the read mechanism based on band-to-band tunneling, while the other gate (G2), positioned adjacent to the first front gate is responsible for charge storage and sustenance. The proposed architecture results in an enhanced SM of ˜1.2 μA μm-1 along with a longer retention time (RT) of ˜1.8 s at 85 °C, for a total length of 600 nm. The double gate architecture towards the source increases the tunneling current and also reduces short channel effects, enhancing SM and scalability, thereby overcoming the critical bottleneck faced by TFET based dynamic memories. The work also discusses the impact of overlap/underlap and interface charges on the performance of TFET based dynamic memory. Insights into device operation demonstrate that the choice of appropriate architecture and biases not only limit the trade-off between SM and RT, but also result in improved scalability with drain voltage and total length being scaled down to 0.8 V and 115 nm, respectively.

Architecture and fiber type of the pyramidalis muscle.

PubMed

Lovering, Richard M; Anderson, Larry D

2008-12-01

The paired pyramidalis muscles are small triangular-shaped muscles that lie between the anterior surface of the rectus abdominus and the posterior surface of the rectus sheath. The precise function of pyramidalis muscles is unclear, but together the muscles are thought to tense the linea alba. The muscles are not always present, or are often unilateral, and vary greatly in size. Their wider inferior margins attach to the pubic symphyses and pubic crests, whereas their narrow superior margins attach to the linea alba. The gross anatomy and innervation of the pyramidalis muscles has been described by others, but their architecture and fiber type have not been determined in previous publications. The purpose of the present paper was therefore to investigate these parameters and place the findings into context for the literature available on this muscle. An example of bilateral pyramidalis muscles was recently encountered in a male cadaver that provided ample tissue for an analysis of its architecture and fiber type. The muscle mass, muscle length, fiber length, and pennation angle of muscle fibers were measured to ascertain physiological cross-sectional area and thereby estimate force production. Fiber type composition was also examined using immunofluorescent labeling. The results show that this is a muscle of mixed fiber type composition, similar to the rectus abdominus, and that the estimated forces generated by this muscle are relatively small.

Crustal architecture of the oblique-slip conjugate margins of George V Land and southeast Australia

USGS Publications Warehouse

Stagg, H.M.J.; Reading, A.M.

2007-01-01

A conceptual, lithospheric-scale cross-section of the conjugate, oblique-slip margins of George V Land, East Antarctica, and southeast Australia (Otway Basin) has been constructed based on the integration of seismic and sample data. This cross-section is characterised by asymmetry in width and thickness, and depth-dependent crustal extension at breakup in the latest Maastrichtian. The broad Antarctic margin (~360 km apparent rift width) developed on thick crust (~42 km) of the Antarctic craton, whereas the narrow Otway margin (~220 km) developed on the thinner crust (~31 km) of the Ross–Delamerian Orogen. The shallow basement (velocities ~5.5 km.s-1) and the deep continental crust (velocities >6.4 km.s-1) appear to be largely absent across the central rift, while the mid-crustal, probably granitic layer (velocities ~6 km.s-1) is preserved. Comparison with published numerical models suggests that the shallow basement and deep crust may have been removed by simple shear, whereas the mid-crust has been ductilely deformed.

The effects of the Er:YAG laser on trabecular bone micro-architecture: Comparison with conventional dental drilling by micro-computed tomographic and histological techniques

PubMed Central

Zeitouni, Jihad; Clough, Bret; Zeitouni, Suzanne; Saleem, Mohammed; Al Aisami, Kenan; Gregory, Carl

2017-01-01

Background: The use of lasers has become increasingly common in the field of medicine and dentistry, and there is a growing need for a deeper understanding of the procedure and its effects on tissue. The aim of this study was to compare the erbium-doped yttrium aluminium garnet (Er:YAG) laser and conventional drilling techniques, by observing the effects on trabecular bone microarchitecture and the extent of thermal and mechanical damage. Methods: Ovine femoral heads were employed to mimic maxillofacial trabecular bone, and cylindrical osteotomies were generated to mimic implant bed preparation. Various laser parameters were tested, as well as a conventional dental drilling technique. The specimens were then subjected to micro-computed tomographic (μCT) histomorphometic analysis and histology. Results: Herein, we demonstrate that mCT measurements of trabecular porosity provide quantitative evidence that laser-mediated cutting preserves the trabecular architecture and reduces thermal and mechanical damage at the margins of the cut. We confirmed these observations with histological studies. In contrast with laser-mediated cutting, conventional drilling resulted in trabecular collapse, reduction of porosity at the margin of the cut and histological signs of thermal damage. Conclusions: This study has demonstrated, for the first time, that mCT and quantification of porosity at the margin of the cut provides a quantitative insight into damage caused by bone cutting techniques. We further show that with laser-mediated cutting, the marrow remains exposed to the margins of the cut, facilitating cellular infiltration and likely accelerating healing. However, with drilling, trabecular collapse and thermal damage is likely to delay healing by restricting the passage of cells to the site of injury and causing localized cell death. PMID:29416849

Re-appraisal of the Magma-rich versus Magma-poor Paradigm at Rifted Margins: consequences for breakup processes

NASA Astrophysics Data System (ADS)

Tugend, J.; Gillard, M.; Manatschal, G.; Nirrengarten, M.; Harkin, C. J.; Epin, M. E.; Sauter, D.; Autin, J.; Kusznir, N. J.; McDermott, K.

2017-12-01

Rifted margins are often classified based on their magmatic budget only. Magma-rich margins are commonly considered to have excess decompression melting at lithospheric breakup compared with steady state seafloor spreading while magma-poor margins have suppressed melting. New observations derived from high quality geophysical data sets and drill-hole data have revealed the diversity of rifted margin architecture and variable distribution of magmatism. Recent studies suggest, however, that rifted margins have more complex and polyphase tectono-magmatic evolutions than previously assumed and cannot be characterized based on the observed volume of magma alone. We compare the magmatic budget related to lithospheric breakup along two high-resolution long-offset deep reflection seismic profiles across the SE-Indian (magma-poor) and Uruguayan (magma-rich) rifted margins. Resolving the volume of magmatic additions is difficult. Interpretations are non-unique and several of them appear plausible for each case involving variable magmatic volumes and mechanisms to achieve lithospheric breakup. A supposedly 'magma-poor' rifted margin (SE-India) may show a 'magma-rich' lithospheric breakup whereas a 'magma-rich' rifted margin (Uruguay) does not necessarily show excess magmatism at lithospheric breakup compared with steady-state seafloor spreading. This questions the paradigm that rifted margins can be subdivided in either magma-poor or magma-rich margins. The Uruguayan and other magma-rich rifted margins appear characterized by an early onset of decompression melting relative to crustal breakup. For the converse, where the onset of decompression melting is late compared with the timing of crustal breakup, mantle exhumation can occur (e.g. SE-India). Our work highlights the difficulty in determining a magmatic budget at rifted margins based on seismic reflection data alone, showing the limitations of margin classification based solely on magmatic volumes. The timing of decompression melting onset and melting rates (magmatic processes) relative to crustal thinning (tectonic processes) appear equally, if not more important, than the magmatic budget for unravelling the evolution of rifted margins.

The soleal line: a cause of tibial pseudoperiostitis.

PubMed

Levine, A H; Pais, M J; Berinson, H; Amenta, P S

1976-04-01

An unusually prominent soleal line (a normal anatomic variant) may mimic periosteal reaction along the posterior margin of the proximal tibial shaft. This area of pseudoperiostitis is differentiated from hyperostoses arising from the anterior tibial tubercle and the interosseous membrane. It is always associated with normal, undisturbed architecture of the underlying bone.

Post-early cretaceous landform evolution along the western margin of the banca~nnia trough, western nsw

USGS Publications Warehouse

Gibson, D.L.

2000-01-01

Previously undated post-Devonian sediments outcropping north of Fowlers Gap station near the western margin of the Bancannia Trough are shown by plant macro- and microfossil determinations to be of Early Cretaceous (most likely Neocomian and/or Aptian) age, and thus part of the Eromanga Basin. They are assigned to the previously defined Telephone Creek Formation. Study of the structural configuration of this unit and the unconformably underlying Devonian rocks suggests that the gross landscape architecture of the area results from post-Early Cretaceous monoclinal folding along blind faults at the western margin of the trough, combined with the effects of differential erosion. This study shows that, while landscape evolution in the area has been dynamic, the major changes that have occurred are on a geological rather than human timescale.

Sequence and facies architecture of the upper Blackhawk Formation and the Lower Castlegate Sandstone (Upper Cretaceous), Book Cliffs, Utah, USA

NASA Astrophysics Data System (ADS)

Yoshida, S.

2000-11-01

High-frequency stratigraphic sequences that comprise the Desert Member of the Blackhawk Formation, the Lower Castlegate Sandstone, and the Buck Tongue in the Green River area of Utah display changes in sequence architecture from marine deposits to marginal marine deposits to an entirely nonmarine section. Facies and sequence architecture differ above and below the regionally extensive Castlegate sequence boundary, which separates two low-frequency (106-year cyclicity) sequences. Below this surface, high-frequency sequences are identified and interpreted as comprising the highstand systems tract of the low-frequency Blackhawk sequence. Each high-frequency sequence has a local incised valley system on top of the wave-dominated delta, and coastal plain to shallow marine deposits are preserved. Above the Castlegate sequence boundary, in contrast, a regionally extensive sheet sandstone of fluvial to estuarine origin with laterally continuous internal erosional surfaces occurs. These deposits above the Castlegate sequence boundary are interpreted as the late lowstand to early transgressive systems tracts of the low-frequency Castlegate sequence. The base-level changes that generated both the low- and high-frequency sequences are attributed to crustal response to fluctuations in compressive intraplate stress on two different time scales. The low-frequency stratigraphic sequences are attributed to changes in the long-term regional subsidence rate and regional tilting of foreland basin fill. High-frequency sequences probably reflect the response of anisotropic basement to tectonism. Sequence architecture changes rapidly across the faulted margin of the underlying Paleozoic Paradox Basin. The high-frequency sequences are deeply eroded and stack above the Paradox Basin, but display less relief and become conformable updip. These features indicate that the area above the Paradox Basin was more prone to vertical structural movements during formation of the Blackhawk-Lower Castlegate succession.

Using crustal thickness, subsidence and P-T-t history on the Iberia-Newfoundland & Alpine Tethys margins to constrain lithosphere deformation modes during continental breakup

NASA Astrophysics Data System (ADS)

Jeanniot, L.; Kusznir, N. J.; Manatschal, G.; Mohn, G.; Beltrando, M.

2013-12-01

Observations at magma-poor rifted margins such as Iberia-Newfoundland show a complex lithosphere deformation history and OCT architecture, resulting in hyper-extended continental crust and lithosphere, exhumed mantle and scattered embryonic oceanic crust before continental breakup and seafloor spreading. Initiation of seafloor spreading requires both the rupture of the continental crust and lithospheric mantle, and the onset of decompressional melting. Their relative timing controls when mantle exhumation may occur; the presence or absence of exhumed mantle provides useful information on the timing of these events and constraints on lithosphere deformation modes. A single kinematic lithosphere deformation mode leading to continental breakup and sea-floor spreading cannot explain observations. We have determined the sequence of lithosphere deformation events, using forward modelling of crustal thickness, subsidence and P-T-t history calibrated against observations on the present-day Iberia-Newfoundland and the fossil analogue Alpine Tethys margins. Lithosphere deformation modes, represented by flow fields, are generated by a 2D finite element viscous flow model (FeMargin), and used to advect lithosphere and asthenosphere temperature and material. FeMargin is kinematically driven by divergent deformation in the topmost upper lithosphere inducing passive upwelling beneath that layer; the upper lithosphere is assumed to deform by extensional faulting and magmatic intrusions, consistent with observations of deformation processes occurring at slow spreading ocean ridges (Cannat, 1996). Buoyancy enhanced upwelling is also included in the kinematic model as predicted by Braun et al (2000). We predict melt generation by decompressional melting using the parameterization and methodology of Katz et al., 2003. We use a series of numerical experiments, tested and calibrated against crustal thicknesses and subsidence observations, to determine the distribution of lithosphere deformation, the contribution of buoyancy driven upwelling and their spatial and temporal evolution including lateral migration. Particle tracking is used to predict P-T-t histories for both Iberia-Newfoundland and the Alpine Tethys conjugate margin transects. The lateral migration of the deformation flow axis has an important control on the rupture of continental crust and lithosphere, melt initiation, their relative timing, the resulting OCT architecture and conjugate margin asymmetry. Initial continental crust thickness and lithosphere temperature structure are important in controlling initial elevation and subsequent subsidence and depositional histories. Numerical models are used to examine the possible isostatic responses of the present-day and fossil analogue rifted margins.

Depositional framework and sequence stratigraphic aspects of the Coniacian Santonian mixed siliciclastic/carbonate Matulla sediments in Nezzazat and Ekma blocks, Gulf of Suez, Egypt

NASA Astrophysics Data System (ADS)

El-Azabi, M. H.; El-Araby, A.

2007-04-01

Superb outcrops of mixed siliciclastic/carbonate rocks mark the Coniacian-Santonian Matulla Formation exposed in Nezzazat and Ekma blocks, west central Sinai. They are built up of various lithofacies that reflect minor fluctuations in relative sea-level from lower intertidal to slightly deep subtidal settings. Relying on the facies characteristics and stratal geometries, the siliciclastic rocks are divided into seven depositional facies, including beach foreshore laminated sands, upper shoreface cross-bedded sandstone, lower shoreface massive bioturbated and wave-rippled sandstones, shallow subtidal siltstone and deep subtidal shale/claystone. The carbonate rocks comprise lower intertidal lime-mudstone, floatstone and dolostone, shallow subtidal skeletal shoal of oyster rudstone/bioclastic grainstone, and shoal margin packstone. Oolitic grain-ironstone and ferribands are partially intervened the facies types. Deposition has taken place under varied conditions of restricted, partly open marine circulation, low to high wave energy and normal to raised salinity during alternating periods of abundant and ceased clastic supply. The facies types are arranged into asymmetric upward-shallowing cycles that record multiple small-scale transgressive-regressive events. Lime-mudstone and sandstone normally terminate the regressive events. Four sequence boundaries marking regional relative sea-level falls divide the Matulla Formation into three stratigraphic units. These boundaries are Turonian/Coniacian, intra-Coniacian, Coniacian/Santonian and Santonian/Campanian. They do not fit with those sequence boundaries proposed in Haq et al.'s global eustatic curves (1988) except for the sea-level fall associated with the intra-Coniacian boundary. Other sequence boundaries have resulted from regional tectonic impact of the Syrian Arc Fold System that has been initiated in north Egypt during the Latest Turonian-Coniacian. These boundaries enclose three well-defined 3rd order depositional sequences; their enclosing shallowing-upward cycles (i.e. parasequences) record the 4th order relative sea-level fluctuations. 34 and 20 parasequence sets, in the order of a few meters to tens of meters thick, mark the Matulla sequences in Nezzazat and Ekma blocks respectively. Each sequence shows an initial phase of rapid sea-level rise with retrogradational sets, followed by lowering sea-level and progradation/aggradation of the parasequence sets. The transgressive deposits display predominance of deep subtidal lagoonal facies, while highstand deposits show an increase in siliciclastic and carbonate facies with the progressive decrease of lagoonal facies. The sedimentary patterns and environments suggest that the regional, partly eustatic sea-level (i.e. intra-Coniacian) changes controlled the overall architecture of the sequence distribution, whereas changes in the clastic input controlled the variations in facies associations within each depositional sequence.

Optimal Control Allocation with Load Sensor Feedback for Active Load Suppression, Experiment Development

NASA Technical Reports Server (NTRS)

Miller, Christopher J.; Goodrick, Dan

2017-01-01

The problem of control command and maneuver induced structural loads is an important aspect of any control system design. The aircraft structure and the control architecture must be designed to achieve desired piloted control responses while limiting the imparted structural loads. The classical approach is to utilize high structural margins, restrict control surface commands to a limited set of analyzed combinations, and train pilots to follow procedural maneuvering limitations. With recent advances in structural sensing and the continued desire to improve safety and vehicle fuel efficiency, it is both possible and desirable to develop control architectures that enable lighter vehicle weights while maintaining and improving protection against structural damage. An optimal control technique has been explored and shown to achieve desirable vehicle control performance while limiting sensed structural loads. The subject of this paper is the design of the optimal control architecture, and provides the reader with some techniques for tailoring the architecture, along with detailed simulation results.

Preface

NASA Astrophysics Data System (ADS)

Mohriak, Webster; Talwani, Manik

In compiling this volume, we have aimed to develop and enhance our current understanding of the structural evolution and sedimentation processes along divergent continental margins. To counteract the unfortunate situation of a lack of modem seismic and potential fields data on circum-Atlantic passive margins in the literature, we have linked new data from oil companies with that of research institutions. To update the data offered in most volumes used as reference works for the study of continental margins, now upwards of 20 years old, and to remedy the dispersal of important, more recent contributions in specialized journals, we present a current synthesis of materials in one volume focused on the deeper geology of the sedimentary basins along continental margins. In the early 1990s, as oil companies and other institutions developed tools to probe deeper into the architecture of passive margin sedimentary basins, a great amount of data based on regional deep seismic profiles evolved rapidly from its specialized niche as geophysical interpretation of the Earth's interior to widespread use by those same companies and institutions. At the same time, these findings demonstrated that some breakthroughs in data acquisition, processing and interpretation initially achieved by research institutions could almost instantaneously be globalized throughout different research groups, thereby influencing the thinking of geoscientists worldwide.

Structural Pain Compensating Flight Control

NASA Technical Reports Server (NTRS)

Miller, Chris J.

2014-01-01

The problem of control command and maneuver induced structural loads is an important aspect of any control system design. Designers must design the aircraft structure and the control architecture to achieve desired piloted control responses while limiting the imparted structural loads. The classical approach is to build the structure with high margins, restrict control surface commands to known good combinations, and train pilots to follow procedural maneuvering limitations. With recent advances in structural sensing and the continued desire to improve safety and vehicle fuel efficiency, it is both possible and desirable to develop control architectures that enable lighter vehicle weights while maintaining and improving protection against structural damage.

Marginal Shape Deep Learning: Applications to Pediatric Lung Field Segmentation.

PubMed

Mansoor, Awais; Cerrolaza, Juan J; Perez, Geovanny; Biggs, Elijah; Nino, Gustavo; Linguraru, Marius George

2017-02-11

Representation learning through deep learning (DL) architecture has shown tremendous potential for identification, localization, and texture classification in various medical imaging modalities. However, DL applications to segmentation of objects especially to deformable objects are rather limited and mostly restricted to pixel classification. In this work, we propose marginal shape deep learning (MaShDL), a framework that extends the application of DL to deformable shape segmentation by using deep classifiers to estimate the shape parameters. MaShDL combines the strength of statistical shape models with the automated feature learning architecture of DL. Unlike the iterative shape parameters estimation approach of classical shape models that often leads to a local minima, the proposed framework is robust to local minima optimization and illumination changes. Furthermore, since the direct application of DL framework to a multi-parameter estimation problem results in a very high complexity, our framework provides an excellent run-time performance solution by independently learning shape parameter classifiers in marginal eigenspaces in the decreasing order of variation. We evaluated MaShDL for segmenting the lung field from 314 normal and abnormal pediatric chest radiographs and obtained a mean Dice similarity coefficient of 0.927 using only the four highest modes of variation (compared to 0.888 with classical ASM 1 (p-value=0.01) using same configuration). To the best of our knowledge this is the first demonstration of using DL framework for parametrized shape learning for the delineation of deformable objects.

Constraints for timing of extensional tectonics in the western margin of the Red Sea in Eritrea

NASA Astrophysics Data System (ADS)

Ghebreab, Woldai; Carter, Andrew; Hurford, Anthony J.; Talbot, Christopher J.

2002-06-01

Recent work on asthenosphere-lithosphere coupling reinforces past observations that active and passive rifting models do not adequately describe real rifts. There remains insufficient knowledge of fundamental controls on rift architecture. In the actively extending Red Sea margin of eastern Eritrea, which lies at the Red Sea/Danakil-Gulf of Aden and the East African rift triple junction zone, the geometry and kinematics of extension are complex and poorly defined due to large data gaps. Extension and sea-floor spreading in both the Red Sea and Gulf of Aden have influenced the Neogene tectonic development of Eritrea but many of the structures have Pan-African origins and do not follow normal plate opening geometries. To constrain the rifting history in eastern Eritrea, apatite fission-track thermochronologic data were measured for 22 Pan-African rock samples. Results identify late Oligocene-early Miocene cooling coincident with extension and erosion along the conjugate margin in Yemen. A younger age group, confined to Mt Ghedem, relates to an episode of fault reactivation and dyke injection that began ˜10 Ma coincident with rotation of the nearby Danakil block. Initially this was driven by onset of sea-floor spreading in the Gulf of Aden and later, in the Pliocene, aided by northward rifting in the Afar depression concomitant with spreading in the Red Sea. These different processes highlight the complex linkage between different extensional events and rift architecture.

Marginal shape deep learning: applications to pediatric lung field segmentation

NASA Astrophysics Data System (ADS)

Mansoor, Awais; Cerrolaza, Juan J.; Perez, Geovany; Biggs, Elijah; Nino, Gustavo; Linguraru, Marius George

2017-02-01

Representation learning through deep learning (DL) architecture has shown tremendous potential for identification, local- ization, and texture classification in various medical imaging modalities. However, DL applications to segmentation of objects especially to deformable objects are rather limited and mostly restricted to pixel classification. In this work, we propose marginal shape deep learning (MaShDL), a framework that extends the application of DL to deformable shape segmentation by using deep classifiers to estimate the shape parameters. MaShDL combines the strength of statistical shape models with the automated feature learning architecture of DL. Unlike the iterative shape parameters estimation approach of classical shape models that often leads to a local minima, the proposed framework is robust to local minima optimization and illumination changes. Furthermore, since the direct application of DL framework to a multi-parameter estimation problem results in a very high complexity, our framework provides an excellent run-time performance solution by independently learning shape parameter classifiers in marginal eigenspaces in the decreasing order of variation. We evaluated MaShDL for segmenting the lung field from 314 normal and abnormal pediatric chest radiographs and obtained a mean Dice similarity coefficient of 0:927 using only the four highest modes of variation (compared to 0:888 with classical ASM1 (p-value=0:01) using same configuration). To the best of our knowledge this is the first demonstration of using DL framework for parametrized shape learning for the delineation of deformable objects.

Architectural patterns of p16 immunohistochemical expression associated with cancer immunity and prognosis of head and neck squamous cell carcinoma.

PubMed

Ryu, Hyang Joo; Kim, Eun Kyung; Heo, Su Jin; Cho, Byoung Chul; Kim, Hye Ryun; Yoon, Sun Och

2017-11-01

We evaluated the expression patterns of p16, which is used as a surrogate marker of HPV infection in head and neck squamous cell carcinoma (HNSCC), in regard to their biological and prognostic implications. p16 expression patterns and infiltrated immune cells were analyzed through immunohistochemistry of p16, CD3, CD8, PD-1, FOXP3, and CD163 on surgically resected HNSCCs (n = 393). Patterns of p16 immunoexpression were defined as STRONG (strong, diffuse expression in cytoplasm, and nucleus in >70% of tumor cells), MARGINAL (expression restricted to tumor margins), MOSAIC (ragged, discontinued expression), NUCLEAR (expression in nuclei only), and ABSENT (no expression). The STRONG pattern was more frequent in the oropharynx, and the MARGINAL pattern was noted only in the oral cavity. MOSAIC and NUCLEAR patterns were noted at variable sites. No two patterns of p16 expression showed the same immune cell composition of CD3+ T cells, CD8+ cytotoxic T cells, PD-1+ T cells, FOXP3+ regulatory T cells, and CD163+ macrophages. In overall and disease-free survival analyses, the STRONG pattern showed the most favorable prognosis, while the NUCLEAR pattern had the worst prognosis. HNSCC anatomical sites, tumor-related immune cell components, and patient outcomes were associated with p16 expression patterns. Each architectural pattern of p16 expression may be related to different biological and prognostic phenotypes. © 2017 APMIS. Published by John Wiley & Sons Ltd.

Marginal Shape Deep Learning: Applications to Pediatric Lung Field Segmentation

PubMed Central

Mansoor, Awais; Cerrolaza, Juan J.; Perez, Geovanny; Biggs, Elijah; Nino, Gustavo; Linguraru, Marius George

2017-01-01

Representation learning through deep learning (DL) architecture has shown tremendous potential for identification, localization, and texture classification in various medical imaging modalities. However, DL applications to segmentation of objects especially to deformable objects are rather limited and mostly restricted to pixel classification. In this work, we propose marginal shape deep learning (MaShDL), a framework that extends the application of DL to deformable shape segmentation by using deep classifiers to estimate the shape parameters. MaShDL combines the strength of statistical shape models with the automated feature learning architecture of DL. Unlike the iterative shape parameters estimation approach of classical shape models that often leads to a local minima, the proposed framework is robust to local minima optimization and illumination changes. Furthermore, since the direct application of DL framework to a multi-parameter estimation problem results in a very high complexity, our framework provides an excellent run-time performance solution by independently learning shape parameter classifiers in marginal eigenspaces in the decreasing order of variation. We evaluated MaShDL for segmenting the lung field from 314 normal and abnormal pediatric chest radiographs and obtained a mean Dice similarity coefficient of 0.927 using only the four highest modes of variation (compared to 0.888 with classical ASM1 (p-value=0.01) using same configuration). To the best of our knowledge this is the first demonstration of using DL framework for parametrized shape learning for the delineation of deformable objects. PMID:28592911

Late differentiation of proximal and distal margins in the Gulf of Aden

NASA Astrophysics Data System (ADS)

Bache, F.; Leroy, S.; D'Acremont, E.; Autin, J.; Watremez, L.; Rouzo, S.

2009-04-01

Non-volcanic passive margins are usually described in three different domains (Boillot et al., 1988), namely (1) the continental domain, where the basement is structured in a series of basins and basement rises, (2) the true oceanic domain, where the bathymetry is relatively smooth, and (3) in between them, a transitional domain referred to as the oceanic-continental transition (OCT), where the basement is partly composed of exhumed mantle. The Gulf of Aden is a young and narrow oceanic basin formed in Oligo-Miocene time between the rifted margins of the Arabian and Somalian plates. The distal margin and particularly the OCT domain were previously studied considering a large set of data (Leroy et al., 2004; d'Acremont et al., 2005; d'Acremont et al., 2006; Autin, 2008). This study focalises on the sedimentary cover identified on seismic reflexion profiles acquired during Encens-Sheba (2000) and Encens (2006) cruises. Sedimentary stratal pattern and seismic facies succession suggest that the differentiation between the proximal and the distal margins occurred very late in the formation of the margin, after the deposition of ~2 km of "syn-OCT" sediments which filled the distal margin grabens. A high position of the proximal and distal margins during rifting and "syn-OCT" sediments deposition could be proposed. The major implication of this evolution should be a shallow nature of "syn-OCT" deposits. The lack of boreholes doesn't permit to affirm this last point. Comparable observations have been described on other passive margins (Moulin, 2003; Moulin et al., 2005; Labails, 2007; Aslanian et al., 2008; Bache, 2008). For some authors, it shows the persistence of a deep thermal anomaly during the early history of the margin (Steckler et al., 1988; Dupré et al., 2007). These observations could be a common characteristic of passive margins evolution and are of major interest for petroleum exploration. Aslanian, D., M. Moulin, O. J.L., P. Unternehr, F. Bache, I. Contrucci, F. Klingelhoefer, C. Labails, L. Matias, H. Nouzé, and M. Rabineau, 2008, Brazilian and African Passive Margins of the Central Segment of the South Atlantic Ocean: Kinematic constraints: Tectonophysics, v. doi: 10.1016/j.tecto.2008.12.016. Autin, J., 2008, Déchirure continentale et segmentation du Golfe d'Aden oriental en contexte de rifting oblique: Ph. D. thesis, Université Pierre et Marie Curie, Paris VI, 310 p. Bache, F., 2008, Evolution Oligo-Miocène des marges du micro océan Liguro Provençal.: Ph. D. thesis, Université de Bretagne Occidentale/CNRS/IFREMER. http://www.ifremer.fr/docelec/notice/2008/notice4768-EN.htm, Brest, 328 p. Boillot, G., J. Girardeau, and J. Kornprobst, 1988, The rifting of the Galicia margin: crustal thinning and emplacement of mantle rocks on the seafloor (ODP Leg 103). In Boillot, G., Winterer, E.L., et al., Proc. ODP, Sci. Results, v. 103, College Station, TX (Ocean Drilling Program), p. 741-756. d'Acremont, E., S. Leroy, M. O. Beslier, N. bellahsen, M. Fournier, C. Robin, M. Maia, and P. Gente, 2005, Structure and evolution of the eastern Gulf of Aden conjugate margins from seismic reflection data: Geophys. J. Int., v. 160, p. 869-890. d'Acremont, E., S. Leroy, M. Maia, P. Patriat, M. O. Beslier, N. Bellahsen, M. Fournier, and P. Gente, 2006, Structure and evolution of the eastern Gulf of Aden: insights from magnetic and gravity data (Encens-Sheba MD117 cruise): Geophys. J. Int., v. 165, p. 786-803. Dupré, S., G. Bertotti, and S. Cloetingh, 2007, Tectonic history along the South Gabon Basin: Anomalous early post-rift subsidence: Mar. Pet. Geol., v. 24, p. 151-172. Labails, C., 2007, La marge sud-marocaine et les premières phases d'ouverture de l'océan Atlantique Central: Ph. D. thesis, Université de Bretagne Occidentale, Brest. Leroy, S., P. Gente, M. Fournier, E. d'Acremont, P. Patriat, M. O. Beslier, N. Bellahsen, M. Maia, A. Blais, J. Perrot, A. Al-Kathiri, S. Merkouriev, J. M. Fleury, P. Y. Ruellan, C. Lepvrier, and P. Huchon, 2004, From rifting to spreading in the Gulf of Aden: a geophysical survey of a young oceanic basin from margin to margin: Terra Nova, v. 16, p. 185-192. Moulin, M., 2003, Etude géologique et géophysique des marges continentales passive: exemple de l'Angola et du Zaire: Ph. D. thesis, Université de Bretagne Occidentale/IFREMER. http://www.ifremer.fr/docelec/doc/2003/these-82.pdf., Brest, 320 p. Moulin, M., D. Aslanian, J. L. Olivet, I. Contrucci, L. Matias, L. Géli, F. Klingelhoefer, H. Nouzé, J. P. Réhault, and P. Unternehr, 2005, Geological constraints on the evolution of the Angolan margin based on reflection and refraction seismic data (Zaïango project): Geophys. J. Int., v. 162, p. 793-810. Steckler, M., A. B. Watts, and J. A. Thorne, 1988, Subsidence and basin modeling at the U.S. Atlantic passive margin, in R. E. Sheridan, and J. A. Grow, eds., The Atlantic Continental Margin: U.S., v. The Geology of Noth America, V1-2, Geological Society of America, p. 399-416.

Model for turbidite-to-contourite continuum and multiple process transport in deep marine settings: examples in the rock record

NASA Astrophysics Data System (ADS)

Stanley, Daniel Jean

1993-01-01

Petrological analysis of geological sections in St. Croix in the Caribbean, the Niesenflysch in Switzerland and the Annot Sandstone in the French Maritime Alps sheds light on multiple process transport in deep marine settings. A model depicting a turbidite-to-contourite continuum of stratal types is applied to these three rock units. Recognition of a diverse suite of bedforms, coupled with analysis of paleocurrents, helps to better interpret depositional origin and basin paleogeography. The St. Croix strata record emplacement by gravity flows and, subsequently, by bottom currents flowing parallel to the base of slope; these sediments accumulated on a lower slope apron. A Niesenflysch section in the Swiss Alps west of Adelboden includes turbidites which were deposited at fairly regular intervals beyond the base of slope, in a setting more distal than that of the St. Croix sequences. Most of these turbidites appear to have been partially reworked by bottom currents related to basin circulation or to density flows from the basin margins. In the Annot Sandstone, reworked turbidites (termed transitional variants) and packets of entirely rippled strata are observed in submarine fan and slope sequences in the Peira-Cava area. In contrast to those in St. Croix and the Niesenflysch, the current-emplaced deposits of the Annot Sandstone are directly associated with fan-valley deposits. Such rippled strata in channels are deposits of gravity flow origin which were subsequently reworked downslope by currents generated by successive gravity flows; they also occur on levees by overbank flow. Consideration of multiple process transport is of special help to interpret sections which are poorly exposed, or which can be examined in cores, or which are located in sequences that have been highly deformed structurally.

Tectonic controls on nearshore sediment accumulation and submarine canyon morphology offshore La Jolla, Southern California

USGS Publications Warehouse

Le Dantec, Nicolas; Hogarth, Leah J.; Driscoll, Neal W.; Babcock, Jeffrey M.; Barnhardt, Walter A.; Schwab, William C.

2010-01-01

CHIRP seismic and swath bathymetry data acquired offshore La Jolla, California provide an unprecedented three-dimensional view of the La Jolla and Scripps submarine canyons. Shore-parallel patterns of tectonic deformation appear to control nearshore sediment thickness and distribution around the canyons. These shore-parallel patterns allow the impact of local tectonic deformation to be separated from the influence of eustatic sea-level fluctuations. Based on stratal geometry and acoustic character, we identify a prominent angular unconformity inferred to be the transgressive surface and three sedimentary sequences: an acoustically laminated estuarine unit deposited during early transgression, an infilling or “healing-phase” unit formed during the transgression, and an upper transparent unit. Beneath the transgressive surface, steeply dipping reflectors with several dip reversals record faulting and folding along the La Jolla margin. Scripps Canyon is located at the crest of an antiform, where the rocks are fractured and more susceptible to erosion. La Jolla Canyon is located along the northern strand of the Rose Canyon Fault Zone, which separates Cretaceous lithified rocks to the south from poorly cemented Eocene sands and gravels to the north. Isopach and structure contour maps of the three sedimentary units reveal how their thicknesses and spatial distributions relate to regional tectonic deformation. For example, the estuarine unit is predominantly deposited along the edges of the canyons in paleotopographic lows that may have been inlets along barrier beaches during the Holocene sea-level rise. The distribution of the infilling unit is controlled by pre-existing relief that records tectonic deformation and erosional processes. The thickness and distribution of the upper transparent unit are controlled by long-wavelength, tectonically induced relief on the transgressive surface and hydrodynamics.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Handford, C.R.

Exploration is increasingly dependent upon obtaining credible stratigraphic interpretations of seismic data. With respect to carbonate platforms, two of the most important seismic-imaging and interpretation problems are (1) distinguishing between lowstand unconformities and drowning unconformities, and (2) recognizing paleokarst reservoirs. Lowstand unconformities vs. drowning unconformities. Many contend that onlapping wedges of strata above sequence boundaries but below the previous shelf break comprise the lowstand systems tract. An alternative view is that onlapping wedges do not record sea level falls, but instead chronicle sea level rises and platform demise. A Mississippian carbonate ramp exposed along the southern margin of North Americamore » is flanked by a siliciclastic lowstand wedge and overlain by a drowning succession of black shales. This dual history of lowstand exposure and drowning formed two baselap surfaces, which lie so close to each other on the shelf that seismic dissemination is almost impossible. The paradox is that although the ramp was terminated by drowning, the visible seismic baselap was due to low-stand exposure. Numerous large fields around the world produce from carbonate reservoirs with a moderate to strong paleokarst overprint. Their discoveries, however, were structurally driven and rarely based upon predrill knowledge of paleokarst systems. In fact, there has been little effort to determine how to recognize paleocave systems in seismic reflection data. To narrow this gap, the sedimentary fill and stratal geometries of modern cave systems were examined and modeled seismically. The models show a passage from continuous reflections in the undisturbed country rock to discontinuous reflections inclined toward the cavern core. Velocity pull-ups and pull-downs are significant where velocity and density contrasts between the country rock and collapsed chamber are important.« less

Valley-fill sequences and onlap geometries, Lower Cretaceous Muddy Sandstone, Kitty Field, Powder River basin, Wyoming

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gardner, M.H.; Gustason, E.R.

1987-05-01

The Muddy Sandstone at Kitty field is a valley-fill sequence that records a late Albian sea level rise and accompanying transgression. The valley was cut during a preceding sea level lowstand. Stratal geometries and facies successions within the valley fill demonstrate the history of transgression was not gradual and progressive. Rather, the valley fill comprises a series of discrete, time-bounded, depositional units which onlap the erosional surface. Five time-bounded depositional units were defined by facies successions and were used to define onlap geometries. Facies successions within individual units record progressive shoaling. Capping each succession, there may be a planar disconformity,more » a thin bioturbated interval, or the deepest water facies of the next depositional event. Thus, the termination of each depositional event is marked by an episode of rapid deepening. At a single geographic location, stratal successions within older depositional units represent more landward facies than those within younger units. Therefore, the onlap geometry of the valley-fill sequence consists of a landward-stepping arrangement of depositional units. The primary reservoirs within the valley-fill sequence, at Kitty field, are laterally coalesced, channel-belt sandstones at the base and barrier island sandstones at the top. Reservoir sandstones of lesser quality occur within the intermediate estuarine facies. The stacking pattern, developed by onlap of the units, results in multiple pay zones within mid-valley reaches. The boundaries of each depositional unit define a high-resolution, chronostratigraphic correlation of valley-fill strata, a correlation corroborated by bentonites. This correlation method gives an accurate description of the internal geometry of valley-fill strata and, therefore, provides a basis for understanding the process of transgressive onlap.« less

San Antonio relay ramp: Area of stratal continuity between large-displacement barrier faults of the Edwards aquifer and Balcones fault zone, central Texas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Collins, E.W.

1996-09-01

The San Antonio relay ramp, a gentle southwest-dipping monocline, formed between the tips of two en echelon master faults having maximum throws of >240 in. Structural analysis of this relay ramp is important to studies of Edwards aquifer recharge and ground-water flow because the ramp is an area of relatively good stratal continuity linking the outcrop belt recharge zone and unconfined aquifer with the downdip confined aquifer. Part of the relay ramp lies within the aquifer recharge zone and is crossed by several southeast-draining creeks, including Salado, Cibolo, and Comal Creeks, that supply water to the ramp recharge area. Thismore » feature is an analog for similar structures within the aquifer and for potential targets for hydrocarbons in other Gulf Coast areas. Defining the ramp is an {approximately}13-km-wide right step of the Edwards Group outcrop belt and the en echelon master faults that bound the ramp. The master faults strike N55-75{degrees}E, and maximum displacement exceeds the {approximately}165-m thickness of the Edwards Group strata. The faults therefore probably serve as barriers to Edwards ground-water flow. Within the ramp, tilted strata gently dip southwestward at {approximately}5 m/km, and the total structural relief along the ramp`s southwest-trending axis is <240 in. The ramp`s internal framework is defined by three fault blocks that are {approximately}4 to {approximately}6 km wide and are bound by northeast-striking faults having maximum throws between 30 and 150 m. Within the fault blocks, local areas of high fracture permeability may exist where smaller faults and joints are well connected.« less

Encoding of marginal utility across time in the human brain.

PubMed

Pine, Alex; Seymour, Ben; Roiser, Jonathan P; Bossaerts, Peter; Friston, Karl J; Curran, H Valerie; Dolan, Raymond J

2009-07-29

Marginal utility theory prescribes the relationship between the objective property of the magnitude of rewards and their subjective value. Despite its pervasive influence, however, there is remarkably little direct empirical evidence for such a theory of value, let alone of its neurobiological basis. We show that human preferences in an intertemporal choice task are best described by a model that integrates marginally diminishing utility with temporal discounting. Using functional magnetic resonance imaging, we show that activity in the dorsal striatum encodes both the marginal utility of rewards, over and above that which can be described by their magnitude alone, and the discounting associated with increasing time. In addition, our data show that dorsal striatum may be involved in integrating subjective valuation systems inherent to time and magnitude, thereby providing an overall metric of value used to guide choice behavior. Furthermore, during choice, we show that anterior cingulate activity correlates with the degree of difficulty associated with dissonance between value and time. Our data support an integrative architecture for decision making, revealing the neural representation of distinct subcomponents of value that may contribute to impulsivity and decisiveness.

Two-dimensional high efficiency thin-film silicon solar cells with a lateral light trapping architecture.

PubMed

Fang, Jia; Liu, Bofei; Zhao, Ying; Zhang, Xiaodan

2014-08-22

Introducing light trapping structures into thin-film solar cells has the potential to enhance their solar energy harvesting as well as the performance of the cells; however, current strategies have been focused mainly on harvesting photons without considering the light re-escaping from cells in two-dimensional scales. The lateral out-coupled solar energy loss from the marginal areas of cells has reduced the electrical yield indeed. We therefore herein propose a lateral light trapping structure (LLTS) as a means of improving the light-harvesting capacity and performance of cells, achieving a 13.07% initial efficiency and greatly improved current output of a-Si:H single-junction solar cell based on this architecture. Given the unique transparency characteristics of thin-film solar cells, this proposed architecture has great potential for integration into the windows of buildings, microelectronics and other applications requiring transparent components.

Influence of the Eastern California Shear Zone on deposition of the Mio-Pliocene Bouse Formation: Insights from the Cibola area, Arizona

USGS Publications Warehouse

Dorsey, Rebecca J.; O'Connell, Brennan; Homan, Mindy B.; Bennett, Scott E. K.

2017-01-01

The Eastern California Shear Zone (ECSZ) is a wide zone of late Cenozoic strike-slip faults and related diffuse deformation that currently accommodates ~20–25% of relative Pacific–North America plate motion in the lower Colorado River region (Fig. 1A; Dokka and Travis, 1990; Miller et al., 2001; Guest et al., 2007; Mahan et al., 2009). The ECSZ is kinematically linked southward to dextral faults in the northern Gulf of California (Bennett et al., 2016a), and it may have initiated ca. 8 Ma when major strike-slip faults developed in the northern Gulf and Salton Trough region (Bennett et al., 2016b; Darin et al., 2016; Woodburne, 2017). Thus deformation related to the ECSZ occurred in the lower Colorado River region during deposition of the Bouse Formation, which is commonly bracketed between 6.0 and 4.8 Ma (House et al., 2008; Sarna-Wojcicki et al., 2011; Spencer et al., 2013) and may be as old as 6–7 Ma in the south (McDougall and Miranda Martínez, 2014, 2016). Post-4.5 Ma broad sagging is recognized along the lower Colorado River (Howard et al., 2015), but the possibility that faults of the ECSZ influenced local to regional subsidence patterns during deposition of the Bouse Formation has received little attention to date (e.g., Homan, 2014; O’Connell et al., 2016). The Bouse Formation is a widespread sequence of late Miocene to early Pliocene deposits exposed discontinuously along the lower Colorado River corridor (Fig. 1A). In the southern Blythe basin it consists of three regionally correlative members: (1) Basal Carbonate, consisting of supratidal and intertidal mud-flat marls, intertidal and shallow subtidal bioclastic grainstone and conglomerate, and subtidal marl; (2) Siliciclastic member, consisting of Colorado River-derived green claystone, red mudstone and siltstone, and cross-bedded river channel sandstone; and (3) Upper Bioclastic member fossiliferous sandy calcarenite, coarse pebbly grainstone, and calcareous-matrix conglomerate (Homan, 2014; Dorsey et al., 2016; O’Connell et al., 2016, 2017). The southern Bouse Formation has been interpreted as recording deposition in either a lake (Spencer and Patchett, 1997; Spencer et al., 2008, 2013; Bright et al., 2016) or shallow marine setting (Buising, 1990; McDougall, 2008; McDougall and Miranda Martínez, 2014; O’Connell et al., 2017).In this paper we summarize key results from five field seasons of detailed stratigraphic analysis south of Cibola, Ariz. ( . 1). The data reveal systematic stratal thinning and thickening, pinch-outs, and wedging patterns in the Bouse Formation that we conclude were produced by syn-depositional tilting in response to growth of normal faults near the eastern margin of the basin. Similar stratal patterns in other nearby areas suggest widespread structural controls on deposition of the Bouse Formation. A palinspastic reconstruction of the lower Colorado River region at 5 Ma, modified from Bennett et al. (2016), provides insight to regional fault geometries in the ECSZ that may have controlled syn-depositional tilting and subsidence in Bouse depocenters shortly prior to and during initiation of the Colorado River.

Deep sea sedimentation processes and geomorphology: Northwest Atlantic continental margin

NASA Astrophysics Data System (ADS)

Mosher, David; Campbell, Calvin; Gardner, Jim; Chaytor, Jason; Piper, David; Rebesco, Michele

2017-04-01

Deep-sea sedimentation processes impart a fundamental control on the morphology of the western North Atlantic continental margin from Blake Spur to Hudson Strait. This fact is illustrated by the variable patterns of cross-margin gradients that are based on extensive new multibeam echo-sounder data informed by subbottom profiler and seismic reflection data. Erosion by off-shelf sediment transport in turbidity currents creates gullies, canyons and channels and a steep upper slope. Amalgamation of these conduits produces singular channels and turbidite fan complexes on the lower slope, flattening slope-profile gradients. The effect is an exponentially decaying "graded" slope profile. Comparatively, sediment mass failure produces steeper upper slopes due to head scarp development and a wedging architecture to the lower slope as deposits thin in the downslope direction. This process results in either a "stepped" slope, and/or a significant downslope gradient change where MTDs pinch out. Large drift deposits created by geostrophic currents are developed all along the margin. Blake Ridge, Sackville Spur, and Hamilton Spur are large detached drifts on disparate parts of the margin. They form a linear "above grade" profile along their crests from the shelf to abyssal plain. Deeper portions of the US continental margin are dominated by the Chesapeake Drift and Hatteras Outer Ridge; both plastered elongate mounded drifts. Farther north, particularly on the Grand Banks margin, are plastered and separated drifts. These drifts form "stepped" slope profiles, where they onlap the margin. Trough-mouth fan complexes become more common along the margin with increasing latitude. Sediment deposition and retention, particularly those dominated by glacigenic debris flows, characterize these segments producing an "above grade" slope profile. Understanding these geomorphological consequences of deep sea sedimentation processes is important to extended continental shelf mapping in which gradients and gradient change is a critical metric.

Coral reef complexes at an atypical windward platform margin: Late Quaternary, southeast Florida

USGS Publications Warehouse

Lidz, B.H.

2004-01-01

Major coral reef complexes rim many modern and ancient carbonate platforms. Their role in margin evolution is not fully understood, particularly when they border a margin atypical of the classic model. Classic windward margins are steeply inclined. The windward margin of southeast Florida is distinct with a very low-gradient slope and a shelf edge ringed with 30-m-high Quaternary outlier reefs on a shallow upper-slope terrace. A newly developed synthesis of temporally well-constrained geologic events is used with surface and subsurface seismic-reflection contours to construct morphogenetic models of four discontinuous reef-complex sequences. The models show uneven subsurface topography, upward and landward buildups, and a previously unreported, rapid, Holocene progradation. The terms backstepped reef-complex margin, backfilled prograded margin, and coalesced reef-complex margin are proposed for sections exhibiting suitable signatures in the stratigraphic record. The models have significant implications for interpretation of ancient analogues. The Florida record chronicles four kinds of geologic events. (1) Thirteen transgressions high enough for marine deposition occurred between ca. 325 ka and the present. Six gave rise to stratigraphically successive coral reef complexes between ca. 185 and ca. 77.8 ka. The seventh reef ecosystem is Holocene. (2) Two primary coral reef architectures built the outer shelf and margin, producing respective ridge-and-swale and reef-and-trough geometries of very different scales. (3) Massive outlier reefs developed on an upper-slope terrace between ca. 106.5 and ca. 80 ka and are inferred to contain corals that would date to highstands at ca. 140 and 125 ka. (4) Sea level remained below elevation of the shelf between ca. 77.8 and ca. 9.6 ka. ?? 2004 Geological Society of America.

The ciliary marginal zone of the zebrafish retina: clonal and time-lapse analysis of a continuously growing tissue.

PubMed

Wan, Yinan; Almeida, Alexandra D; Rulands, Steffen; Chalour, Naima; Muresan, Leila; Wu, Yunmin; Simons, Benjamin D; He, Jie; Harris, William A

2016-04-01

Clonal analysis is helping us understand the dynamics of cell replacement in homeostatic adult tissues (Simons and Clevers, 2011). Such an analysis, however, has not yet been achieved for continuously growing adult tissues, but is essential if we wish to understand the architecture of adult organs. The retinas of lower vertebrates grow throughout life from retinal stem cells (RSCs) and retinal progenitor cells (RPCs) at the rim of the retina, called the ciliary marginal zone (CMZ). Here, we show that RSCs reside in a niche at the extreme periphery of the CMZ and divide asymmetrically along a radial (peripheral to central) axis, leaving one daughter in the peripheral RSC niche and the other more central where it becomes an RPC. We also show that RPCs of the CMZ have clonal sizes and compositions that are statistically similar to progenitor cells of the embryonic retina and fit the same stochastic model of proliferation. These results link embryonic and postembryonic cell behaviour, and help to explain the constancy of tissue architecture that has been generated over a lifetime. © 2016. Published by The Company of Biologists Ltd.

Enhancing our View of the Reservoir: New Insights into Deepwater Gulf of Mexico fields using Frequency Decomposition

NASA Astrophysics Data System (ADS)

Murat, M.

2017-12-01

Color-blended frequency decomposition is a seismic attribute that can be used to educe or draw out and visualize geomorphological features enabling a better understanding of reservoir architecture and connectivity for both exploration and field development planning. Color-blended frequency decomposition was applied to seismic data in several areas of interest in the Deepwater Gulf of Mexico. The objective was stratigraphic characterization to better define reservoir extent, highlight depositional features, identify thicker reservoir zones and examine potential connectivity issues due to stratigraphic variability. Frequency decomposition is a technique to analyze changes in seismic frequency caused by changes in the reservoir thickness, lithology and fluid content. This technique decomposes or separates the seismic frequency spectra into discrete bands of frequency limited seismic data using digital filters. The workflow consists of frequency (spectral) decomposition, RGB color blending of three frequency slices, and horizon or stratal slicing of the color blended frequency data for interpretation. Patterns were visualized and identified in the data that were not obvious on standard stacked seismic sections. These seismic patterns were interpreted and compared to known geomorphological patterns and their environment of deposition. From this we inferred the distribution of potential reservoir sand versus non-reservoir shale and even finer scale details such as the overall direction of the sediment transport and relative thickness. In exploratory areas, stratigraphic characterization from spectral decomposition is used for prospect risking and well planning. Where well control exists, we can validate the seismic observations and our interpretation and use the stratigraphic/geomorphological information to better inform decisions on the need for and placement of development wells.

Proglacial deltaic landforms and stratigraphic architecture as a proxy for reconstructing past ice-sheet margin positions

NASA Astrophysics Data System (ADS)

Dietrich, Pierre; Ghienne, Jean-François; Normandeau, Alexandre; Lajeunesse, Patrick

2016-04-01

Deltaic landforms and related stratigraphic architectures are frequently used as proxy for reconstruction of past continental or marine environmental evolutions. Indeed, in addition to autocyclic processes, emplacement of deltaic systems is primarily controlled by changes in sediment supply and relative sea-level (RSL). In our study, we investigated several proglacial deltaic complexes emplaced since the last deglaciation over more than 700 km along the St. Lawrence North Shore (Québec, Canada). Their geomorphic and stratigraphic records allowed us to infer the retreat pattern of the Laurentide Ice Sheet fronts. Field investigation of representative deltaic complexes revealed an archetypal morphostratigraphic evolution forced by the retreat of the ice margin in a context of falling RSL (glacio-isostatic rebound). The base of the stratigraphic successions consists of outwash fan deposits emplaced in the early deglaciation when ice margin stillstanded immediately beyond the depositional area. The middle part of the succession consists of proglacial delta deposits corresponding to the retreat of the ice margin in the hinterland. At that time, glaciogenic supplies allowed an active progradation preventing fluvial entrenchment in spite of the forced regressive context. The upper part of the succession consists of staged shoreline deposits reworking the rim of the proglacial deltas. These deposits mark the retreat of the ice margin from the drainage basin and the subsequent drop in glaciogenics. Important fluvial entrenchment occurred in the same time, though rates of RSL fall were reduced. We generalize this stratigraphic framework by using solely the landforms (from DEM, aerial photographs or satellite images) tied to deltaic complex developments along the St. Lawrence North Shore. This approach permits an integrated study at the scale of the whole basin even where no field data is available. Recognizing the three steps evidenced from the stratigraphic record ads constrains on the successive ice margin positions through deglaciation. Top surface of the outwash fans, marking the deglaciation of the area, lies at or near the marine limit (highest altitude reached by the post-glacial sea) and is commonly flat; the top surface of the proglacial deltas, recording the upland recession of the ice margin, is gently-sloped basinward, without evidence of fluvial entrenchment; finally, the top surface of coastal deposits, marking the retreat of the ice margin from the drainage basin, is characterized by raised beaches incised by meandering rivers. Determining ages of these successive landforms (14C dating, sea-level curves) allowed us to reconstruct the pattern of ice-sheet retreat since the Younger Dryas up to almost the final disappearance of the Quebec Ice Dome at ~6 kyr BP.

The Baltic Klint beneath the central Baltic Sea and its comparison with the North Estonian Klint

NASA Astrophysics Data System (ADS)

Tuuling, Igor; Flodén, Tom

2016-06-01

Along its contact with the Baltic Shield, the margin of the East European Platform reveals a well-developed, flooded terraced relief. The most striking and consistent set of escarpments at the contact of the Lower Palaeozoic calcareous and terrigenous rocks, known as the Baltic Klint (BK), extends from northwest of Russia to the Swedish island of Öland. Marine seismic reflection profiling in 1990-2004 revealed the central Baltic Sea Klint (BSK) section in detail and enabled comparison of its geology/geomorphology with a classical klint-section onshore, namely the North Estonian Klint (NEK). The conception of the BK onshore, which is based on the land-sea separating terraced relief in northern Estonia, is not fully applicable beneath the sea. Therefore, we consider that the BSK includes the entire terraced Cambrian outcrop. We suggest the term "Baltic Klint Complex" to include the well-terraced margin of the Ordovician limestone outcrop, which is weakly developed in Estonia. Because of a steady lithological framework of the bedrock layers across the southern slope of the Fennoscandian Shield, the central BSK in the western and the NEK in the eastern part of the Baltic Homocline have largely identical morphologies. The North Estonian Ordovician limestone plateau with the calcareous crest of the BK extends across the central Baltic Sea, whereas morphological changes/variations along the Klint base occur due to the east-westerly lithostratigraphic/thickness changes in the siliciclastic Cambrian sequence. The verge of the NEK, located some 30-50 m above sea level, starts to drop in altitude as its east-westerly course turns to northeast-southwest in western Estonia. Further westwards, the BK shifts gradually into southerly deepening (0.1-0.2°) layers as its crest drops to c. 150 m below sea level (b.s.l.) near Gotska Sandön. This course change is accompanied by a considerable decrease in thickness of the platform sedimentary cover, as below the central Baltic Sea the stratal sequence is 150-250 m thinner than in northern Estonia. This has facilitated a deviation of the terraced relief-forming Cenozoic rivers traversing east-westerly across the southern slope of the Fennoscandian Shield and forming different morphostructures in its eastern and western parts. Thus, a low-lying central Baltic Sea depression with well-developed asymmetrical cuesta valleys and terraces occur in the western half of the Baltic Homocline. In its eastern part, however, the only explicitly shaped cuesta valley along the shield-platform boundary forms a narrow east-westerly branch/gulf of the Baltic Sea (Gulf of Finland). The well-terraced southern margin of this gulf runs along the contact of the outcropping terrigenous and calcareous rocks, rises above the sea and forms a complex landform known as the NEK.

Geodynamic models of the Wilson Cycle: From rifts to mountains to rifts

NASA Astrophysics Data System (ADS)

Buiter, Susanne; Tetreault, Joya; Torsvik, Trond

2015-04-01

The Wilson Cycle theory that oceans close and reopen along the former suture is a fundamental concept in plate tectonics. The theory suggests that subduction initiates at a passive margin, closing the ocean, and that future continental extension localises at the ensuing collision zone. Each stage of the Wilson Cycle will therefore be characterised by inherited structural and thermal heterogeneities. Here we investigate the role of Wilson Cycle inheritance by considering the influence of (1) passive margin structure on continental collision and (2) collision zones on passive margin formation. Passive margins may be preferred locations for subduction initiation because inherited faults and areas of exhumed serpentinized mantle may weaken a margin enough to localise shortening. If subduction initiates at a passive margin, the shape and structure of the passive margins will affect future continental collision. Our review of present-day passive margins along the Atlantic and Indian Oceans reveals that most passive margins are located on former collision zones. Continental break-up occurs on relatively young sutures, such as Morocco-Nova Scotia, and on very old sutures, such as the Greenland-Labrador and East Antarctica-Australia systems. This implies that it is not always post-collisional collapse that initiates the extensional phase of a Wilson Cycle. We highlight the impact of collision zone inheritance on continental extension and rifted margin architecture. We show numerical experiments of one Wilson Cycle of subduction, collision, and extension. Subduction initiates at a tapered passive margin. Closure of a 60 Ma ocean leads to continental collision and slab break-off, followed by some tens of kilometres of slab eduction. Mantle flow above the sinking detached slab enhances deformation in the rift area. The resulting rift exposes not only continental crust, but also subduction-related sediments and oceanic crust remnants. Renewed subduction in the post-collision phase is enabled by lithosphere delamination and slab rollback, leading to back-arc extension in a style similar to the Tyrrhenian Sea.

Glimpses of East Antarctica: Aeromagnetic and satellite magnetic view from the central Transantarctic Mountains of East Antarctica

USGS Publications Warehouse

Finn, Carol A.; Goodge, John W.

2010-01-01

Aeromagnetic and satellite magnetic data provide glimpses of the crustal architecture within the Ross Sea sector of the enigmatic, ice-covered East Antarctic shield critical for understanding both global tectonic and climate history. In the central Transantarctic Mountains (CTAM), exposures of Precambrian basement, coupled with new high-resolution magnetic data, other recent aeromagnetic transects, and satellite magnetic and seismic tomography data, show that the shield in this region comprises an Archean craton modified both by Proterozoic magmatism and early Paleozoic orogenic basement reactivation. CTAM basement structures linked to the Ross Orogeny are imaged 50–100 km farther west than previously mapped, bounded by inboard upper crustal Proterozoic granites of the Nimrod igneous province. Magnetic contrasts between craton and rift margin sediments define the Neoproterozoic rift margin, likely reactivated during Ross orogenesis and Jurassic extension. Interpretation of satellite magnetic and aeromagnetic patterns suggests that the Neoproterozoic rift margin of East Antarctica is offset by transfer zones to form a stepwise series of salients tracing from the CTAM northward through the western margin of the Wilkes Subglacial Basin to the coast at Terre Adélie. Thinned Precambrian crust inferred to lie east of the rift margin cannot be imaged magnetically because of modification by Neoproterozoic and younger tectonic events.

3-D Structure and Morphology of the S-reflector Detachment Fault, Offshore Galicia, Spain

NASA Astrophysics Data System (ADS)

Schuba, C. N.; Sawyer, D. S.; Gray, G. G.; Morgan, J.; Bull, J.; Shillington, D. J.; Jordan, B.; Reston, T. J.

2017-12-01

The crustal architecture of passive continental margins provides valuable clues for understanding rift initiation and evolution. The Galicia margin is an archetypal magma-poor margin displaying exhumed serpentinized mantle, and is an optimal setting in which to examine rift-related processes. A new 3-D seismic reflection volume images this margin in great detail. The S-reflector detachment fault, one of the most prominent structural features associated with the Galicia margin, is imaged as a continuous interface over an area of 600 km2. The top and base of the fault zone can be mapped independently, which enables seismic attribute analysis of this significant structure. RMS amplitude maps extracted from this interface show localized patches of high amplitude stripes that coincide with thickness variations of the fault zone and undulations in the bounding surfaces of the fault. These variations bear similarities to grooves on the fault surface such as slickensides, and appear to have developed as the fault zone evolved. These features thus represent good indicators of the kinematics of the fault system. In general, there is good correlation between S-reflector morphology and the overriding fault intersections; however this relationship does not appear to be present with the fault gouge thickness.

Marginal Space Deep Learning: Efficient Architecture for Volumetric Image Parsing.

PubMed

Ghesu, Florin C; Krubasik, Edward; Georgescu, Bogdan; Singh, Vivek; Yefeng Zheng; Hornegger, Joachim; Comaniciu, Dorin

2016-05-01

Robust and fast solutions for anatomical object detection and segmentation support the entire clinical workflow from diagnosis, patient stratification, therapy planning, intervention and follow-up. Current state-of-the-art techniques for parsing volumetric medical image data are typically based on machine learning methods that exploit large annotated image databases. Two main challenges need to be addressed, these are the efficiency in scanning high-dimensional parametric spaces and the need for representative image features which require significant efforts of manual engineering. We propose a pipeline for object detection and segmentation in the context of volumetric image parsing, solving a two-step learning problem: anatomical pose estimation and boundary delineation. For this task we introduce Marginal Space Deep Learning (MSDL), a novel framework exploiting both the strengths of efficient object parametrization in hierarchical marginal spaces and the automated feature design of Deep Learning (DL) network architectures. In the 3D context, the application of deep learning systems is limited by the very high complexity of the parametrization. More specifically 9 parameters are necessary to describe a restricted affine transformation in 3D, resulting in a prohibitive amount of billions of scanning hypotheses. The mechanism of marginal space learning provides excellent run-time performance by learning classifiers in clustered, high-probability regions in spaces of gradually increasing dimensionality. To further increase computational efficiency and robustness, in our system we learn sparse adaptive data sampling patterns that automatically capture the structure of the input. Given the object localization, we propose a DL-based active shape model to estimate the non-rigid object boundary. Experimental results are presented on the aortic valve in ultrasound using an extensive dataset of 2891 volumes from 869 patients, showing significant improvements of up to 45.2% over the state-of-the-art. To our knowledge, this is the first successful demonstration of the DL potential to detection and segmentation in full 3D data with parametrized representations.

Lower Badenian coarse-grained Gilbert deltas in the southern margin of the Western Carpathian Foredeep basin

NASA Astrophysics Data System (ADS)

Nehyba, Slavomír

2018-02-01

Two coarse-grained Gilbert-type deltas in the Lower Badenian deposits along the southern margin of the Western Carpathian Foredeep (peripheral foreland basin) were newly interpreted. Facies characterizing a range of depositional processes are assigned to four facies associations — topset, foreset, bottomset and offshore marine pelagic deposits. The evidence of Gilbert deltas within open marine deposits reflects the formation of a basin with relatively steep margins connected with a relative sea level fall, erosion and incision. Formation, progradation and aggradation of the thick coarse-grained Gilbert delta piles generally indicate a dramatic increase of sediment supply from the hinterland, followed by both relatively continuous sediment delivery and an increase in accommodation space. Deltaic deposition is terminated by relatively rapid and extended drowning and is explained as a transgressive event. The lower Gilbert delta was significantly larger, more areally extended and reveals a more complicated stratigraphic architecture than the upper one. Its basal surface represents a sequence boundary and occurs around the Karpatian/Badenian stratigraphic limit. Two coeval deltaic branches were recognized in the lower delta with partly different stratigraphic arrangements. This different stratigraphic architecture is mostly explained by variations in the sediment delivery and /or predisposed paleotopography and paleobathymetry of the basin floor. The upper delta was recognized only in a restricted area. Its basal surface represents a sequence boundary probably reflecting a higher order cycle of a relative sea level rise and fall within the Lower Badenian. Evidence of two laterally and stratigraphically separated coarse-grained Gilbert deltas indicates two regional/basin wide transgressive/regressive cycles, but not necessarily of the same order. Provenance analysis reveals similar sources of both deltas. Several partial source areas were identified (Mesozoic carbonates of the Northern Calcareous Alps and the Western Carpathians, crystalline rocks of the eastern margin of the Bohemian Massif, older sedimentary infill of the Carpathian Foredeep and/or the North Alpine Foreland Basin, sedimentary rocks of the Western Carpathian/Alpine Flysch Zone).

A Role for Semantic Web Technologies in Patient Record Data Collection

NASA Astrophysics Data System (ADS)

Ogbuji, Chimezie

Business Process Management Systems (BPMS) are a component of the stack of Web standards that comprise Service Oriented Architecture (SOA). Such systems are representative of the architectural framework of modern information systems built in an enterprise intranet and are in contrast to systems built for deployment on the larger World Wide Web. The REST architectural style is an emerging style for building loosely coupled systems based purely on the native HTTP protocol. It is a coordinated set of architectural constraints with a goal to minimize latency, maximize the independence and scalability of distributed components, and facilitate the use of intermediary processors.Within the development community for distributed, Web-based systems, there has been a debate regarding themerits of both approaches. In some cases, there are legitimate concerns about the differences in both architectural styles. In other cases, the contention seems to be based on concerns that are marginal at best. In this chapter, we will attempt to contribute to this debate by focusing on a specific, deployed use case that emphasizes the role of the Semantic Web, a simple Web application architecture that leverages the use of declarative XML processing, and the needs of a workflow system. The use case involves orchestrating a work process associated with the data entry of structured patient record content into a research registry at the Cleveland Clinic's Clinical Investigation department in the Heart and Vascular Institute.

Architecture and sedimentary processes on the mid-Norwegian continental slope: A 2.7 Myr record from extensive seismic evidence

NASA Astrophysics Data System (ADS)

Montelli, A.; Dowdeswell, J. A.; Ottesen, D.; Johansen, S. E.

2018-07-01

Quaternary architectural evolution and sedimentary processes on the mid-Norwegian continental slope are investigated using margin-wide three- and two-dimensional seismic datasets. Of ∼100,000 km3 sediments delivered to the mid-Norwegian shelf and slope over the Quaternary, ∼75,000 km3 comprise the slope succession. The structural high of the Vøring Plateau, characterised by initially low (∼1-2°) slope gradients and reduced accommodation space, exerted a strong control over the long-term architectural evolution of the margin. Slope sediment fluxes were higher on the Vøring Plateau area, increasing up to ∼32 km3 ka-1 during the middle Pleistocene, when fast-flowing ice streams advanced to the palaeo-shelf edge. Resulted in a more rapid slope progradation on the Vøring Plateau, these rates of sediment delivery are high compared to the maximum of ∼7 km3 ka-1 in the adjacent sectors of the slope, characterised by steeper slope (∼3-5°), more available accommodation space and smaller or no palaeo-ice streams on the adjacent shelves. In addition to the broad-scale architectural evolution, identification of more than 300 buried slope landforms provides an unprecedented level of detailed, process-based palaeoenvironmental reconstruction. Channels dominate the Early Pleistocene record (∼2.7-0.8 Ma), during which glacimarine sedimentation on the slope was influenced by dense bottom-water flow and turbidity currents. Morphologic signature of glacigenic debris-flows appear within the Middle-Late Pleistocene (∼0.8-0 Ma) succession. Their abundance increases towards Late Pleistocene, marking a decreasing role for channelized turbidity currents and dense water flows. This broad-scale palaeo-environmental shift coincides with the intensification of Northern Hemispheric glaciations, highlighting first-order climate control on the sedimentary processes in high-latitude continental slopes.

Guidelines and Metrics for Assessing Space System Cost Estimates

DTIC Science & Technology

2008-01-01

analysis time, reuse tooling, models , mechanical ground-support equipment [MGSE]) High mass margin ( simplifying assumptions used to bound solution...engineering environment changes High reuse of architecture, design , tools, code, test scripts, and commercial real- time operating systems Simplified life...Coronal Explorer TWTA traveling wave tube amplifier USAF U.S. Air Force USCM Unmanned Space Vehicle Cost Model USN U.S. Navy UV ultraviolet UVOT UV

Low Average Sidelobe Slot Array Antennas for Radiometer Applications

NASA Technical Reports Server (NTRS)

Rengarajan, Sembiam; Zawardzki, Mark S.; Hodges, Richard E.

2012-01-01

In radiometer applications, it is required to design antennas that meet low average sidelobe levels and low average return loss over a specified frequency bandwidth. It is a challenge to meet such specifications over a frequency range when one uses resonant elements such as waveguide feed slots. In addition to their inherent narrow frequency band performance, the problem is exacerbated due to modeling errors and manufacturing tolerances. There was a need to develop a design methodology to solve the problem. An iterative design procedure was developed by starting with an array architecture, lattice spacing, aperture distribution, waveguide dimensions, etc. The array was designed using Elliott s technique with appropriate values of the total slot conductance in each radiating waveguide, and the total resistance in each feed waveguide. Subsequently, the array performance was analyzed by the full wave method of moments solution to the pertinent integral equations. Monte Carlo simulations were also carried out to account for amplitude and phase errors introduced for the aperture distribution due to modeling errors as well as manufacturing tolerances. If the design margins for the average sidelobe level and the average return loss were not adequate, array architecture, lattice spacing, aperture distribution, and waveguide dimensions were varied in subsequent iterations. Once the design margins were found to be adequate, the iteration was stopped and a good design was achieved. A symmetric array architecture was found to meet the design specification with adequate margin. The specifications were near 40 dB for angular regions beyond 30 degrees from broadside. Separable Taylor distribution with nbar=4 and 35 dB sidelobe specification was chosen for each principal plane. A non-separable distribution obtained by the genetic algorithm was found to have similar characteristics. The element spacing was obtained to provide the required beamwidth and close to a null in the E-plane end-fire direction. Because of the alternating slot offsets, grating lobes called butterfly lobes are produced in non-principal planes close to the H-plane. An attempt to reduce the influence of such grating lobes resulted in a symmetric design.

The Magmatic Budget of Rifted Margins: is it Related to Inheritance?

NASA Astrophysics Data System (ADS)

Manatschal, G.; Tugend, J.; Gillard, M.; Sauter, D.

2017-12-01

High quality reflection and refraction seismic surveys show a divergent style of margin architecture often referred to as magma-poor or magma-rich. More detailed studies show, however, that the evolution of these margins can be similar, despite the variable quantity and distribution of magmatism. These observations suggest that simple relations between magmatic and extensional systems are inappropriate to describe the magmatic history of rifted margins. Moreover, the study of magmatic additions indicates that they may occur, prior to, during or after lithospheric breakup. Furthermore, the observation that the magmatic budget may change very abruptly along strike and across the margin is difficult to reconcile with the occurrence of plumes or other deep-seated large-scale mantle phenomena only. These overall observations result in questions on how magmatic and tectonic processes are interacting during rifting and lithospheric breakup and on how far the inherited composition and temperature of the decompressing mantle may control the magmatic budget during rifting. In our presentation we will review examples from present-day and fossil rifted margins to discuss their structural and magmatic evolution and whether they are considered as magma-rich or magma-poor. The key questions that we aim to address are: 1) whether decompression melting is the driving force, or rather the consequence of extension, 2) how far the magmatic budget is controlled by inherited mantle composition and temperature, and 3) how important magma storage is during initial stages of rifting. Eventually, we will discuss to what extent the evolution of margins may reflect the interplay between inheritance (innate/"genetic code") and the actual physical processes (acquired/external factors).

An amorphous titanium dioxide metal insulator metal selector device for resistive random access memory crossbar arrays with tunable voltage margin

NASA Astrophysics Data System (ADS)

Cortese, Simone; Khiat, Ali; Carta, Daniela; Light, Mark E.; Prodromakis, Themistoklis

2016-01-01

Resistive random access memory (ReRAM) crossbar arrays have become one of the most promising candidates for next-generation non volatile memories. To become a mature technology, the sneak path current issue must be solved without compromising all the advantages that crossbars offer in terms of electrical performances and fabrication complexity. Here, we present a highly integrable access device based on nickel and sub-stoichiometric amorphous titanium dioxide (TiO2-x), in a metal insulator metal crossbar structure. The high voltage margin of 3 V, amongst the highest reported for monolayer selector devices, and the good current density of 104 A/cm2 make it suitable to sustain ReRAM read and write operations, effectively tackling sneak currents in crossbars without compromising fabrication complexity in a 1 Selector 1 Resistor (1S1R) architecture. Furthermore, the voltage margin is found to be tunable by an annealing step without affecting the device's characteristics.

Effect on Bone Architecture of Marginal Grooves in Dental Implants Under Occlusal Loaded Conditions in Beagle Dogs.

PubMed

Kato, Hatsumi; Kuroshima, Shinichiro; Inaba, Nao; Uto, Yusuke; Sawase, Takashi

2018-02-01

The aim of this study was to clarify whether marginal grooves on dental implants affect osseointegration, bone structure, and the alignment of collagen fibers to determine bone quality under loaded conditions. Anodized Ti-6Al-4V alloy dental implants, with and without marginal grooves (test and control implants, respectively), were used (3.7 × 8.0 mm). Fourth premolars and first molars of 6 beagle mandibles were extracted. Two control and test implants were placed in randomly selected healed sites at 12 weeks after tooth extraction. Screw-retained single crowns for first molars were fabricated. Euthanasia was performed at 8 weeks after the application of occlusal forces. Implant marginal bone level, bone to implant contact (BIC), bone structure around dental implants, and the alignment of collagen fibers determining bone quality were analyzed. The marginal bone level in test implants was significantly higher than that in control implants. Occlusal forces significantly increased BIC in test implants ( P = .007), whereas BIC did not change in control implants, irrespective of occlusal forces ( P = .303). Moreover, occlusal forces significantly increased BIC in test implants compared with control implants ( P = .032). Additionally, occlusal forces preferentially aligned collagen fibers in test implants, but not control implants. Hence, marginal grooves on dental implants have positive effects on increased osseointegration and adapted bone quality based on the preferential alignment of collagen fibers around dental implants under loaded conditions.

Encoding of marginal utility across time in the human brain

PubMed Central

Pine, Alex; Seymour, Ben; Roiser, Jonathan P; Bossaerts, Peter; Friston, Karl J.; Curran, H. Valerie; Dolan, Raymond J.

2010-01-01

Marginal utility theory prescribes the relationship between the objective property of the magnitude of rewards and their subjective value. Despite its pervasive influence, however, there is remarkably little direct empirical evidence for such a theory of value, let alone of its neurobiological basis. We show that human preferences in an inter-temporal choice task are best described by a model that integrates marginally diminishing utility with temporal discounting. Using functional magnetic resonance imaging (fMRI), we show that activity in the dorsal striatum encodes both the marginal utility of rewards, over and above that which can be described by their magnitude alone, and the discounting associated with increasing time. In addition, our data show that dorsal striatum may be involved in integrating subjective valuation systems inherent to time and magnitude, thereby providing an overall metric of value used to guide choice behaviour. Furthermore, during choice we show that anterior cingulate activity correlates with the degree of difficulty associated with dissonance between value and time. Our data support an integrative architecture for decision-making, revealing the neural representation of distinct subcomponents of value that may contribute to impulsivity and decisiveness. PMID:19641120

Coherent array of branched filamentary scales along the wing margin of a small moth

NASA Astrophysics Data System (ADS)

Yoshida, Akihiro; Tejima, Shin; Sakuma, Masayuki; Sakamaki, Yositaka; Kodama, Ryuji

2017-04-01

In butterflies and moths, the wing margins are fringed with specialized scales that are typically longer than common scales. In the hindwings of some small moths, the posterior margins are fringed with particularly long filamentary scales. Despite the small size of these moth wings, these scales are much longer than those of large moths and butterflies. In the current study, photography of the tethered flight of a small moth, Phthorimaea operculella, revealed a wide array composed of a large number of long filamentary scales. This array did not become disheveled in flight, maintaining a coherent sheet-like structure during wingbeat. Examination of the morphology of individual scales revealed that each filamentary scale consists of a proximal stalk and distal branches. Moreover, not only long scales but also shorter scales of various lengths were found to coexist in each small section of the wing margin. Scale branches were ubiquitously and densely distributed within the scale array to form a mesh-like architecture similar to a nonwoven fabric. We propose that possible mechanical interactions among branched filamentary scales, mediated by these branches, may contribute to maintaining a coherent sheet-like structure of the scale array during wingbeat.

'Mafia Baroque': post-socialist architecture and urban planning in Bulgaria.

PubMed

Holleran, Max

2014-03-01

This paper traces the reception of the architectural style known as 'Mafia Baroque' within the professions of architecture and urban planning in Bulgaria. The debate within these professions was strongly linked to the general decline of power among former intellectual elites and the specific decline of architects and planners, who were sidelined as arbiters of 'good taste' and disempowered as regulators of urban growth. The reaction to this style also highlights the rise in public concern over corruption and organized crime and dissatisfaction with post-socialist urbanization. This paper chronicles the extent of changes in construction and regulation in Bulgaria during the 1990s and argues that planners and architects were challenged not only by their professional marginalization but also by a deeper embarrassment over cultural change. It then relates this debate to broader post-socialist anxieties over insufficient regulation of urbanization and fear of failing to meet Western European goals for economic and political change. © London School of Economics and Political Science 2014.

Resilient Organizational Architectures for Command and Control

DTIC Science & Technology

2014-07-03

is the capability margin available immediately at the time of disruption or attack. Reactive Capacity accounts for the fact that certain systems are...changes during the survival phase (post disruption). GMU/SAL 22 A parameter locus is generated to account for how key parameters affecting... accounts for this difference. In the case of flexibility, the augmented MOC 37 performs best in terms of Proportion of Use. A smaller proportion of its

Flexural bending of southern Tibet in a retro foreland setting

PubMed Central

Wang, Erchie; Kamp, Peter J. J.; Xu, Ganqing; Hodges, Kip V.; Meng, Kai; Chen, Lin; Wang, Gang; Luo, Hui

2015-01-01

The highest elevation of the Tibetan Plateau, lying 5,700 m above sea level, occurs within the part of the Lhasa block immediately north of the India-Tibet suture zone (Yarlung Zangbo suture zone, YZSZ), being 700 m higher than the maximum elevation of more northern parts of the plateau. Various mechanisms have been proposed to explain this differentially higher topography and the rock uplift that led to it, invoking crustal compression or extension. Here we present the results of structural investigations along the length of the high elevation belt and suture zone, which rather indicate flexural bending of the southern margin of the Lhasa block (Gangdese magmatic belt) and occurrence of an adjacent foreland basin (Kailas Basin), both elements resulting from supra-crustal loading of the Lhasa block by the Zangbo Complex (Indian plate rocks) via the Great Counter Thrust. Hence we interpret the differential elevation of the southern margin of the plateau as due originally to uplift of a forebulge in a retro foreland setting modified by subsequent processes. Identification of this flexural deformation has implications for early evolution of the India-Tibet continental collision zone, implying an initial (Late Oligocene) symmetrical architecture that subsequently transitioned into the present asymmetrical wedge architecture. PMID:26174578

Parvovirus Induced Alterations in Nuclear Architecture and Dynamics

PubMed Central

Ihalainen, Teemu O.; Niskanen, Einari A.; Jylhävä, Juulia; Paloheimo, Outi; Dross, Nicolas; Smolander, Hanna; Langowski, Jörg; Timonen, Jussi; Vihinen-Ranta, Maija

2009-01-01

The nucleus of interphase eukaryotic cell is a highly compartmentalized structure containing the three-dimensional network of chromatin and numerous proteinaceous subcompartments. DNA viruses induce profound changes in the intranuclear structures of their host cells. We are applying a combination of confocal imaging including photobleaching microscopy and computational methods to analyze the modifications of nuclear architecture and dynamics in parvovirus infected cells. Upon canine parvovirus infection, expansion of the viral replication compartment is accompanied by chromatin marginalization to the vicinity of the nuclear membrane. Dextran microinjection and fluorescence recovery after photobleaching (FRAP) studies revealed the homogeneity of this compartment. Markedly, in spite of increase in viral DNA content of the nucleus, a significant increase in the protein mobility was observed in infected compared to non-infected cells. Moreover, analyzis of the dynamics of photoactivable capsid protein demonstrated rapid intranuclear dynamics of viral capsids. Finally, quantitative FRAP and cellular modelling were used to determine the duration of viral genome replication. Altogether, our findings indicate that parvoviruses modify the nuclear structure and dynamics extensively. Intranuclear crowding of viral components leads to enlargement of the interchromosomal domain and to chromatin marginalization via depletion attraction. In conclusion, parvoviruses provide a useful model system for understanding the mechanisms of virus-induced intranuclear modifications. PMID:19536327

Thermal Management Tools for Propulsion System Trade Studies and Analysis

NASA Technical Reports Server (NTRS)

McCarthy, Kevin; Hodge, Ernie

2011-01-01

Energy-related subsystems in modern aircraft are more tightly coupled with less design margin. These subsystems include thermal management subsystems, vehicle electric power generation and distribution, aircraft engines, and flight control. Tighter coupling, lower design margins, and higher system complexity all make preliminary trade studies difficult. A suite of thermal management analysis tools has been developed to facilitate trade studies during preliminary design of air-vehicle propulsion systems. Simulink blocksets (from MathWorks) for developing quasi-steady-state and transient system models of aircraft thermal management systems and related energy systems have been developed. These blocksets extend the Simulink modeling environment in the thermal sciences and aircraft systems disciplines. The blocksets include blocks for modeling aircraft system heat loads, heat exchangers, pumps, reservoirs, fuel tanks, and other components at varying levels of model fidelity. The blocksets have been applied in a first-principles, physics-based modeling and simulation architecture for rapid prototyping of aircraft thermal management and related systems. They have been applied in representative modern aircraft thermal management system studies. The modeling and simulation architecture has also been used to conduct trade studies in a vehicle level model that incorporates coupling effects among the aircraft mission, engine cycle, fuel, and multi-phase heat-transfer materials.

Comparison of hydrothermal activity between the Adriatic and the Red Sea rift margins

NASA Astrophysics Data System (ADS)

Ball, Philip; Incerpi, Nicolò; Birkle, Peter; Lacsamana, Elizabeth; Manatschal, Gianreto; Agar, Susan; Zhang, Shuo; Borsato, Ron

2017-04-01

Detailed field studies, and access to high-quality seismic reflection and refraction data have led to an improved understanding of the architecture and evolution of magma poor and magma rich margins. Associated with the spatial-temporal evolution of the rift, it is evident that there are evolving, extensive, fluid-rock interactions due to the infiltration of fluids within the sediment, basement and lithospheric mantle. Key questions therefore arise: What are the different fluid-rock reactions that can be typed to different geodynamic stages of the rift evolution? What are their compositions and how do they interact with their environment (basement, sediments, evaporites, hydrosphere, and magmatism)? What are the implications for the evolution of the margin rheology, thermal structure, depositional environments/organic matter maturity, and reservoir quality? The Adriatic paleo-rifted margin is preserved in both SE Switzerland and northern Italy. The field exposures provide a unique opportunity to study the fluid flow history of a hyperextended magma poor extensional margin. Analysis of breccias, cement veins and replacement minerals reveal that the margin records a complex, long-lasting history of dolomitization, calcification and silicification during the Jurassic rifting. The Red Sea by contrast is a young rifted margin. It differs from the paleo-Adriatic margin by several characteristics: volcanism is more evident, and syn-tectonic sediments, including evaporites (halite and anhydrite) are thicker. Several core and fluid samples are available from both onshore and offshore wells, which reveal rift-related hydrothermal alteration. In addition, we find evidence for the presence of an extreme dynamic hydraulic system with infiltration of surface water into sub-salt units during Late Pleistocene. In this study we present results from petrographic and geochemical analysis of basement and sedimentary rocks from Adriatic field-derived samples and core/subsurface fluid samples for the Eastern Red Sea margin. The results are presented using rift domain interpretations, thereby enabling the simple comparison of the observed hydrothermal alteration within a first-order (spatial temporal) rift geodynamic framework.

The role of upper-regime flow bedforms in the morphodynamics of submarine channels

NASA Astrophysics Data System (ADS)

Covault, Jacob A.; Kostic, Svetlana; Fildani, Andrea

2014-05-01

Advances in acoustic imaging of submarine canyons and channels have provided accurate renderings of seafloor geomorphology. Still, a fundamental understanding of channel inception, evolution, sediment transport, and the nature of the currents traversing these channels remains elusive. Here, we review a mosaic of geomorphology, shallow stratigraphy, and morphodynamics of channelized deep-water depositional systems of tectonically active slopes offshore of California, USA. These systems are imaged in high-resolution multi-beam sonar bathymetry (dominant frequency ~200 kHz) and seismic-reflection (2-16 kHz) data. From north to south, the Monterey East, Lucia Chica, and San Mateo channelized deep-water depositional systems show a breadth of geomorphology and stratigraphic architecture, including channel reaches of varying sinuosity, levees, terraces within channels, and crescent-shaped bedforms, especially in the thalwegs of incipient channel elements. Morphodynamic numerical modeling is combined with interpretations of seafloor and shallow subsurface stratigraphic imagery to demonstrate that the crescent-shaped bedforms common to channel thalwegs are likely to be cyclic steps. We propose that net-erosional and net-depositional cyclic steps play a fundamental role in the formation, filling, and maintenance phases of submarine channels in continental margins with high gradient, locally rugose bathymetry. These margins include passive-margin slopes subjected to gravity-driven tectonic deformation. In such settings, high gradients support the development of densimetric Froude-supercritical turbidity currents, and abrupt slope breaks can promote hydraulic jumps and the spontaneous evolution of an erodible seabed into cyclic steps. This morphodynamic investigation of turbidity currents and the seafloor has the potential to enhance prediction of the locations, stratigraphic evolution, and architecture of submarine canyon-channel systems.

A Comparison of Recent Organic and Inorganic Carbon Isotope Records: Why Do They Covary in Some Settings and Not In Others?

NASA Astrophysics Data System (ADS)

Oehlert, A. M.; Swart, P. K.

2013-12-01

Covariance between inorganic and organic δ13C records has been used to determine whether a deposit has been altered by diagenesis, how the dynamics of the global carbon cycle changed during the production of the sediments in the deposit, and also for chronostratigraphic correlations. Although covariant records are observed in the ancient geologic record in a variety of depositional environments, such comparisons are not widely applied to modern deposits where definitive data regarding sediment producers, sea level fluctuations, and changes in the global carbon cycle are available. This study uses paired δ13C records from cores collected by the Ocean Drilling Program from three modern periplatform settings (the Great Bahama Bank, the Great Australian Bight, and the Great Barrier Reef), and two pelagic settings (the Walvis Ridge, and the Madingley Rise). These sites were selected in order to assess the influence of several different environmental factors including; sediment and organic matter producers, sediment mineralogy, margin architecture, sea level oscillations, and sediment transport pathways. In the three periplatform settings, multiple cores arranged in a margin to basin transect were analyzed in order to provide insights into the effects of downslope sediment transport. The preliminary results of this study suggest that sea level oscillations and margin architecture may artificially generate a covarying relationship in periplatform sediments that is unrelated to changes in the global carbon cycle. Furthermore, preliminary results from the Walvis Ridge and the Madingley Rise sediments suggest that the relationship between inorganic and organic δ13C records may not always exhibit a positive covariance as is currently assumed for pelagic carbonates.

Polyphase tectono-magmatic and fluid history related to mantle exhumation in an ultra-distal rift domain: example of the fossil Platta domain, SE Switzerland

NASA Astrophysics Data System (ADS)

Epin, Marie-Eva; Manatschal, Gianreto; Amann, Méderic; Lescanne, Marc

2017-04-01

Despite the fact that many studies have investigated mantle exhumation at magma-poor rifted margins, there are still numerous questions concerning the 3D architecture, magmatic, fluid and thermal evolution of these ultra-distal domains that remain unexplained. Indeed, it has been observed in seismic data from ultra-distal magma-poor rifted margins that top basement is heavily structured and complex, however, the processes controlling the morpho-tectonic and magmatic evolution of these domains remain unknown. The aim of this study is to describe the 3D top basement morphology of an exhumed mantle domain, exposed over 200 km2 in the fossil Platta domain in SE Switzerland, and to define the timing and processes controlling its evolution. The examined Platta nappe corresponds to a remnant of the former ultra-distal Adriatic margin of the Alpine Tethys. The rift-structures are relatively well preserved due to the weak Alpine tectonic and metamorphic overprint during the emplacement in the Alpine nappe stack. Detailed mapping of parts of the Platta nappe enabled us to document the top basement architecture of an exhumed mantle domain and to investigate its link to later, rift/oceanic structures, magmatic additions and fluids. Our observations show a polyphase and/or complex: 1) deformation history associated with mantle exhumation along low-angle exhumation faults overprinted by later high-angle normal faults, 2) top basement morphology capped by magmato-sedimentary rocks, 3) tectono-magmatic evolution that includes gabbros, emplaced at deeper levels and subsequently exhumed and overlain by younger extrusive magmatic additions, and 4) fluid history including serpentinization, calcification, hydrothermal vent, rodingitization and spilitization affecting exhumed mantle and associated magmatic rocks. The overall observations provide important information on the temporal and spatial evolution of the tectonic, magmatic and fluid systems controlling the formation of ultra-distal magma-poor rifted margins as well as the processes controlling lithospheric breakup. In this context, our field observations can help to better understand the tectono-magmatic processes associated to these, not yet drilled domains that may form in young, narrow rifted margins (e.g. Red Sea, Gulf of Aden) or may represent the Ocean-Continent Transition in more mature, magma-poor Atlantic type systems.

Mass transport-related stratal disruption and sedimentary products

NASA Astrophysics Data System (ADS)

Ogata, Kei; Mutti, Emiliano; Tinterri, Roberto

2010-05-01

From an outcrop perspective, mass transport deposit are commonly represented by "chaotic" units, characterized by dismembered and internally deformed slide blocks of different sizes and shapes, embedded in a more or less abundant fine-grained matrix. The large amount of data derived from geophysical investigations of modern continental margins have permitted the characterization of the overall geometry of many of these deposits, which, however, remain still relatively poorly described from outcrop studies of collisional basins. Results of this work show that in mass-transport deposits an unsorted, strongly mixed, relatively fine-grained clastic matrix almost invariably occurs in irregularly interconnected patches and pseudo-veins, infilling space between large clasts and blocks. We interpreted the aspect of this matrix as typical of a liquefied mixture of water and sediment, characterized by an extremely high mobility due to overpressured conditions, as evidenced by both lateral and vertical injections. On a much larger scale this kind of matrix is probably represented by the seismically "transparent" facies separating slide blocks of many mass-transport deposits observed in seismic-reflection profiles. The inferred mechanism of matrix production suggests a progressive soft-sediment deformation, linked to different phases of submarine landslide evolution (i.e. triggering, translation, accumulation and post-depositional stages), leading to an almost complete stratal disruption within the chaotic units. From our data we suggest that most submarine landslides move because of the development of ductile shear zones marked by the presence of "overpressured" matrix, both internally and along the basal surface. The matrix acts as a lubricating medium, accommodating friction forces and deformation, thus permitting the differential movement of discrete internal portions and enhancing the submarine slide mobility. Based on our experience, we suggest that this kind of deposit is quite common in the sedimentary record though still poorly reported and understood. Mutti and Carminatti (oral presentation from Mutti et al., 2006) have suggested to call these deposits "blocky-flow deposits", i.e. the deposit of a complex flow that is similar to a debris flow, or hyper-concentrated flow, except that it carries also out-size coherent and internally deformed blocks (meters to hundreds of meters across) usually arranged in isolated slump folds. The origin of blocky flows is difficult to understand on presently available data, particularly because it involves the contemporary origin of coherent slide blocks and a plastic flow that carries them as floating elements over considerable run-out distances. The recognition of the above-mentioned characteristics should be a powerful tool to discriminate sedimentary and tectonic "chaotic" units within accretionary systems, and to distinguish submarine landslide deposits transported as catastrophic blocky flows (and therefore part of the broad family of sediment gravity flows) from those in which transport took place primarily along shear planes (i.e. slumps, coherent slides), also highlighting a possible continuum from slides to turbidity currents. The discussed examples fall into a broad category of submarine slide deposits ranging from laterally extensive carbonate megabreccias (lower-middle Eocene "megaturbidites" of the south-central Pyrenees), to mass transport deposits with a very complex internal geometry developed in a highly tectonically mobile basin (upper Eocene - lower Oligocene Ranzano Sandstone, northern Apennines). References: Mutti, E., Carminatti, M., Moreira, J.L.P. & Grassi, A.A. (2006) - Chaotic Deposits: examples from the Brazilian offshore and from outcrop studies in the Spanish Pyrenees and Northern Apennines, Italy. - A.A.P.G. Annual Meeting, April 9-12, Houston, Texas.

Genome-wide association mapping and agronomic impact of cowpea root architecture.

PubMed

Burridge, James D; Schneider, Hannah M; Huynh, Bao-Lam; Roberts, Philip A; Bucksch, Alexander; Lynch, Jonathan P

2017-02-01

Genetic analysis of data produced by novel root phenotyping tools was used to establish relationships between cowpea root traits and performance indicators as well between root traits and Striga tolerance. Selection and breeding for better root phenotypes can improve acquisition of soil resources and hence crop production in marginal environments. We hypothesized that biologically relevant variation is measurable in cowpea root architecture. This study implemented manual phenotyping (shovelomics) and automated image phenotyping (DIRT) on a 189-entry diversity panel of cowpea to reveal biologically important variation and genome regions affecting root architecture phenes. Significant variation in root phenes was found and relatively high heritabilities were detected for root traits assessed manually (0.4 for nodulation and 0.8 for number of larger laterals) as well as repeatability traits phenotyped via DIRT (0.5 for a measure of root width and 0.3 for a measure of root tips). Genome-wide association study identified 11 significant quantitative trait loci (QTL) from manually scored root architecture traits and 21 QTL from root architecture traits phenotyped by DIRT image analysis. Subsequent comparisons of results from this root study with other field studies revealed QTL co-localizations between root traits and performance indicators including seed weight per plant, pod number, and Striga (Striga gesnerioides) tolerance. The data suggest selection for root phenotypes could be employed by breeding programs to improve production in multiple constraint environments.

Food for thought: how nutrients regulate root system architecture.

PubMed

Shahzad, Zaigham; Amtmann, Anna

2017-10-01

The spatial arrangement of the plant root system (root system architecture, RSA) is very sensitive to edaphic and endogenous signals that report on the nutrient status of soil and plant. Signalling pathways underpinning RSA responses to individual nutrients, particularly nitrate and phosphate, have been unravelled. Researchers have now started to investigate interactive effects between two or more nutrients on RSA. Several proteins enabling crosstalk between signalling pathways have recently been identified. RSA is potentially an important trait for sustainable and/or marginal agriculture. It is generally assumed that RSA responses are adaptive and optimise nutrient uptake in a given environment, but hard evidence for this paradigm is still sparse. Here we summarize recent advances made in these areas of research. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

To what extent can intracrater layered deposits that lack clear sedimentary textures be used to infer depositional environments?

NASA Astrophysics Data System (ADS)

Cadieux, Sarah B.; Kah, Linda C.

2015-03-01

Craters within Arabia Terra, Mars, contain hundreds of meters of layered strata showing systematic alternation between slope- and cliff-forming units, suggesting either rhythmic deposition of distinct lithologies or similar lithologies that experienced differential cementation. On Earth, rhythmically deposited strata can be examined in terms of stratal packaging, wherein the interplay of tectonics, sediment deposition, and base level (i.e., the position above which sediment accumulation is expected to be temporary) result in changes in the amount of space available for sediment accumulation. These predictable patterns of sediment deposition can be used to infer changes in basin accommodation regardless of the mechanism of deposition (e.g. fluvial, lacustrine, or aeolian). Here, we analyze sedimentary deposits from three craters (Becquerel Crater, Danielson Crater, Crater A) in Arabia Terra. Each crater contains layered deposits that are clearly observed in orbital images. Although orbital images are insufficient to specifically determine the origin of sedimentary deposits, depositional couplets can be interpreted in terms of potential accommodation space available for deposition, and changes in the distribution of couplet thickness through stratigraphy can be interpreted in terms of changing base level and the production of new accommodation space. Differences in stratal packaging in these three craters suggest varying relationships between sedimentary influx, sedimentary base level, and concomitant changes in accommodation space. Previous groundwater upwelling models hypothesize that layered sedimentary deposits were deposited under warm climate conditions of early Mars. Here, we use observed stacking patterns to propose a model for deposition under cold climate conditions, wherein episodic melting of ground ice could raise local base level, stabilize sediment deposition, and result in differential cementation of accumulated strata. Such analysis demonstrates that a first-order understanding of sedimentary deposition and accumulation-despite a lack of textural information that inhibits interpretation of depositional mechanism-can provide insight into potentially changeable depositional conditions of early Mars.

Task shifting HIV care in rural district hospitals in Cameroon: evidence of comparable antiretroviral treatment-related outcomes between nurses and physicians in the Stratall ANRS/ESTHER trial.

PubMed

Boullé, Charlotte; Kouanfack, Charles; Laborde-Balen, Gabrièle; Carrieri, Maria Patrizia; Dontsop, Marlise; Boyer, Sylvie; Aghokeng, Avelin Fobang; Spire, Bruno; Koulla-Shiro, Sinata; Delaporte, Eric; Laurent, Christian

2013-04-15

Task shifting to nurses for antiretroviral therapy (ART) is promoted by the World Health Organization to compensate for the severe shortage of physicians in Africa. We assessed the effectiveness of task shifting from physicians to nurses in rural district hospitals in Cameroon. We performed a cohort study using data from the Stratall trial, designed to assess monitoring strategies in 2006-2010. ART-naive patients were followed up for 24 months after treatment initiation. Clinical visits were performed by nurses or physicians. We assessed the associations between the consultant ratio (ie, the ratio of the number of nurse-led visits to the number of physician-led visits) and HIV virological success, CD4 recovery, mortality, and disease progression to death or to the World Health Organization clinical stage 4 in multivariate analyses. Of the 4141 clinical visits performed in 459 patients (70.6% female, median age 37 years), a quarter was task shifted to nurses. The consultant ratio was not significantly associated with virological success [odds ratio 1.00, 95% confidence interval (CI): 0.59 to 1.72, P = 0.990], CD4 recovery (coefficient -3.6, 95% CI: -35.6; 28.5, P = 0.827), mortality (time ratio 1.39, 95% CI: 0.27 to 7.06, P = 0.693), or disease progression (time ratio 1.60, 95% CI: 0.35 to 7.37, P = 0.543). This study brings important evidence about the comparability of ART-related outcomes between HIV models of care based on physicians or nurses in resource-limited settings. Investing in nursing resources for the management of noncomplex patients should help reduce costs and patient waiting lists while freeing up physician time for the management of complex cases, for mentoring and supervision activities, and for other health interventions.

The formation of giant clastic extrusions at the end of the Messinian Salinity Crisis

NASA Astrophysics Data System (ADS)

Kirkham, Christopher; Cartwright, Joe; Hermanrud, Christian; Jebsen, Christopher

2018-01-01

This paper documents the discovery of five multi-km scale lensoid bodies that directly overlie the upper surface of the thick (>1 km) Messinian Evaporite sequence. They were identified through the analysis of 3D seismic data from the western Nile Cone. The convergence of the upper and lower bounding reflections of these lensoid bodies, their external and internal reflection configuration, the positive 'depositional' relief at their upper surface, and the stratal relationship with underlying and overlying deposits supports the interpretation that these are giant clastic extrusions. The interpretations combined with the stratal position of these clastic extrusions demonstrate a prior unsuspected link between periods of major environment change and basin hydrodynamics on a plate scale. All five lensoid bodies were extruded onto a single, seismically resolvable marker horizon correlatable with the end of the Messinian Salinity Crisis (Horizon M). It is argued that the source of these clastic extrusions is pre-Messinian in origin, which implies massive sediment remobilisation at depth in the pre-evaporitic succession and intrusion through the thick evaporite layer. We propose that the scale and timing of this dramatic event was primed and triggered by near-lithostatic overpressure in the pre-evaporitic sediments generated through (1) their rapid burial and loading during the Messinian Salinity Crisis and (2) catastrophic re-flooding during its immediate aftermath. The largest of these clastic extrusions has a volume of over c. 116 km3, making it amongst the largest extruded sedimentary bodies described on Earth. The findings extend the understanding of the upper scale of other analogous clastic extrusions such as mud volcanoes and sediment-hosted hydrothermal systems. Following the 2006 eruption of the Lusi sediment-hosted hydrothermal system in Indonesia, an understanding of the upper scale limit of clastic extrusions has even greater societal relevance, in order to increase awareness of the risk posed by the potential size and longevity of future giant clastic extrusions.

Arabian Plate Deformation: The role of inherited structures in the localization of strain in the Red Sea extensional system

NASA Astrophysics Data System (ADS)

Aldaajani, T.; Furlong, K.; Malservisi, R.

2017-12-01

The Red Sea rift structural architecture changes dramatically along strike from narrow localized spreading (with creation of new oceanic crust) in the south to asymmetrical diffuse extension north of 21 ° latitude. The region of diffuse extension falls within a triangle that is bounded to the east by the Sarhan graben, (a Cenozoic failed rift), to the west by the northern Red Sea Rift, and to the south by the Makkah-Madinah-Nafud (MMN) volcanic line. Geological observations appear to show that tectonic stresses acting on inherited structures within the NW Arabian margin are associated with the region of diffuse extension. In contrast, in the southern Red Sea, a single strong block within the SW Arabian margin led to localize the extension there. Using current velocities from more than 30 GNSS stations distributed within the Arabian plate, we are able to map its rigidity and the distribution of strain along the plate margin. The data show that the transition between the two styles of extension within the Red Sea (crustal accretion vs crustal extension) corresponds with a transition between rigid behavior and diffuse extension within the Arabian Plate. This suggests that the preexisting structures within the Arabian plate play a significant role in the style of extension along the Red Sea margin.

Extent and architecture of major fault systems between northern Victoria Land and the eastern margin of the Wilkes Subglacial Basin (East Antarctica)

NASA Astrophysics Data System (ADS)

Armadillo, E.; Ferraccioli, F.; Balbi, P.; Bozzo, E.

2013-12-01

Terrane bounding and intra-terrane faults of the Ross Orogen in East Antarctica are linked to several phases of Cambrian to Ordovician age subduction and accretion along the active paleo-Pacific margin of Gondwana. Here we compile and analyse new enhanced aeromagnetic anomaly images over the Northern Victoria Land (NVL) segment of the Ross Orogen and the eastern margin of the Wilkes Subglacial Basin (WSB) that help constrain the extent and structural architecture of these fault systems and enable us re-assess their tectonic evolution. Long-wavelength magnetic lows and residual Bouguer gravity highs are modelled as several-km thick inverted sedimentary basins of early Cambrian(?) age. Tectonic inversion occurred along major thrust faults during the late stages of the Ross Orogen, forming a major high-grade pop-up structure within the central Wilson Terrane, flanked by lower grade rocks. The Prince Albert Fault System can now be recongnised as being located to the west of the Exiles Thrust fault system rather than representing its southern continuation. Relatively thin sheets of mylonitic sheared granitoids and possible ultramafic lenses are associated with the late-Ross (ca 480 Ma) Exiles Thrust fault system, while significantly larger and thicker batholiths were emplaced along the Prince Albert Fault System. Recent zircon U-Pb dating over small exposures of gabbro-diorites within the Prince Albert Mountains to the south lead us to propose that this part of the magmatic arc was emplaced during an earlier phase of subduction (~520 Ma or older?), compared to the late-Ross intrusions to the east. Whether the Prince Albert Fault System was indeed a major cryptic suture in early Cambrian times (Ferraccioli et al., 2002, GRL) remains speculative, but possible. Our aeromagnetic interpretation leads us to conclude that these inherited terrane bounding and intra-terrane fault systems of the Ross Orogen exerted a key influence on Cenozoic tectonic blocks and faults of the Transantarctic Mountains, and that the eastern margin of the WSB adjacent to NVL was also strongly controlled by a complex array of major intraplate strike-slip fault systems.

Formation and evolution of magma-poor margins, an example of the West Iberia margin

NASA Astrophysics Data System (ADS)

Perez-Gussinye, Marta; Andres-Martinez, Miguel; Morgan, Jason P.; Ranero, Cesar R.; Reston, Tim

2016-04-01

The West Iberia-Newfoundland (WIM-NF) conjugate margins have been geophysically and geologically surveyed for the last 30 years and have arguably become a paradigm for magma-poor extensional margins. Here we present a coherent picture of the WIM-NF rift to drift evolution that emerges from these observations and numerical modeling, and point out important differences that may exist with other magma-poor margins world-wide. The WIM-NF is characterized by a continental crust that thins asymmetrically and a wide and symmetric continent-ocean transition (COT) interpreted to consist of exhumed and serpentinised mantle with magmatic products increasing oceanward. The architectural evolution of these margins is mainly dominated by cooling under very slow extension velocities (<~6 mm/yr half-rate) and a lower crust that most probably was not extremely weak at the start of rifting. These conditions lead to a system where initially deformation is distributed over a broad area and the upper, lower crust and lithosphere are decoupled. As extension progresses upper, lower, crust and mantle become tightly coupled and deformation localizes due to strengthening and cooling during rifting. Coupling leads to asymmetric asthenospheric uplift and weakening of the hanginwall of the active fault, where a new fault forms. This continued process leads to the formation of an array of sequential faults that dip and become younger oceanward. Here we show that these processes acting in concert: 1) reproduce the margin asymmetry observed at the WIM-NF, 2) explain the fault geometry evolution from planar, to listric to detachment like by having one common Andersonian framework, 3) lead to the symmetric exhumation of mantle with little magmatism, and 4) explain the younging of the syn-rift towards the basin centre and imply that unconformities separating syn- and post-rift may be diachronous and younger towards the ocean. Finally, we show that different lower crustal rheologies lead to different patterns of extension and to an abrupt transition to oceanic crust, even at magma-poor margins.

Marginal reticular cells: a stromal subset directly descended from the lymphoid tissue organizer

PubMed Central

Katakai, Tomoya

2012-01-01

The architecture of secondary lymphoid organs (SLOs) is supported by several non-hematopoietic stromal cells. Currently it is established that two distinct stromal subsets, follicular dendritic cells and fibroblastic reticular cells, play crucial roles in the formation of tissue compartments within SLOs, i.e., the follicle and T zone, respectively. Although stromal cells in the anlagen are essential for SLO development, the relationship between these primordial cells and the subsets in adulthood remains poorly understood. In addition, the roles of stromal cells in the entry of antigens into the compartments through some tissue structures peculiar to SLOs remain unclear. A recently identified stromal subset, marginal reticular cells (MRCs), covers the margin of SLOs that are primarily located in the outer edge of follicles and construct a unique reticulum. MRCs are closely associated with specialized endothelial or epithelial structures for antigen transport. The similarities in marker expression profiles and successive localization during development suggest that MRCs directly descend from organizer stromal cells in the anlagen. Therefore, MRCs are thought to be a crucial stromal component for the organization and function of SLOs. PMID:22807928

High-resolution receiver function imaging reveals Colorado Plateau lithospheric architecture and mantle-supported topography

USGS Publications Warehouse

Domingo, Dorothy L.; R. Aster,; S. Grand,; J Ni,; W.S. Baldridge,; David C. Wilson USGS,

2010-01-01

After maintaining elevations near sea level for over 500 million years, the Colorado Plateau (CP) has a present average elevation of 2 km. We compute new receiver function images from the first dense seismic transect to cross the plateau that reveal a central CP crustal thickness of 42–50 km thinning to 30–35 km at the CP margins. Isostatic calculations show that only approximately 20% of central CP elevations can be explained by thickened crust alone, with the CP edges requiring nearly total mantle compensation. We calculate an uplift budget showing that CP buoyancy arises from a combination of crustal thickening, heating and alteration of the lithospheric root, dynamic support from mantle upwelling, and significant buoyant edge effects produced by small-scale convecting asthenosphere at its margins.

2D and 3D Modeling of the Stratigraphic Sequences at the Adriatic and Rhone Continental Margins

DTIC Science & Technology

2005-09-30

Grenerczy, D. Medak, S. Stein, and J. C. Weber (Eds.). The Adria Microplate : GPS Geodesy, Tectonics , and Hazards. Kluwer Academic Publisher, pp. 93-116... tectonics , and their influences on sequence architecture. John Swenson, with assistance from Chris Paola, Juan Fedele, myself and others have jointly...exploration of the margin’s response to variations in sea level, sediment supply, tectonic subsidence, and wave climate over longer timescales. I am

Quantitative Genetic Architecture at Latitudinal Range Boundaries: Reduced Variation but Higher Trait Independence.

PubMed

Paccard, Antoine; Van Buskirk, Josh; Willi, Yvonne

2016-05-01

Species distribution limits are hypothesized to be caused by small population size and limited genetic variation in ecologically relevant traits, but earlier studies have not evaluated genetic variation in multivariate phenotypes. We asked whether populations at the latitudinal edges of the distribution have altered quantitative genetic architecture of ecologically relevant traits compared with midlatitude populations. We calculated measures of evolutionary potential in nine Arabidopsis lyrata populations spanning the latitudinal range of the species in eastern and midwestern North America. Environments at the latitudinal extremes have reduced water availability, and therefore plants were assessed under wet and dry treatments. We estimated genetic variance-covariance (G-) matrices for 10 traits related to size, development, and water balance. Populations at southern and northern distribution edges had reduced levels of genetic variation across traits, but their G-matrices were more spherical; G-matrix orientation was unrelated to latitude. As a consequence, the predicted short-term response to selection was at least as strong in edge populations as in central populations. These results are consistent with genetic drift eroding variation and reducing the effectiveness of correlational selection at distribution margins. We conclude that genetic variation of isolated traits poorly predicts the capacity to evolve in response to multivariate selection and that the response to selection may frequently be greater than expected at species distribution margins because of genetic drift.

Sedimentation and tectonics in the southern Bida Basin, Nigeria: depositional response to varying tectonic context

DOE Office of Scientific and Technical Information (OSTI.GOV)

Braide, S.P.

1990-05-01

The Upper Cretaceous Bida basin of central Nigeria is sandwiched between the Precambrian schist belts of the Northern Nigerian massif and the West African craton. Of interest is the southern part of the basin, which developed in continental settings, because the facies architecture of the sedimentary fill suggests a close relation between sedimentation dynamics and basin margin tectonics. This relationship is significant to an understanding of the basin's origin, which has been controversial. A simple sag and rift origin has been suggested, and consequently dominated the negative thinking on the hydrocarbon prospects of the basin which were considered poor. Thismore » detailed study of the facies indicates rapid basin-wide changes from various alluvial fan facies through flood-basin and deltaic facies to lacustrine facies. Paleogeographic reconstruction suggests lacustrine environments were widespread and elongate. Lacustrine environments occurred at the basin's axis and close to the margins. This suggests the depocenter must have migrated during the basin's depositional history and subsided rapidly to accommodate the 3.5-km-thick sedimentary fill. Although distinguishing pull-apart basins from rift basins, based solely on sedimentologic grounds, may be difficult, the temporal migration of the depocenter, as well as the basin architecture of upward coarsening cyclicity, show a strong tectonic and structural overprint that suggests a tectonic framework for the Southern Bida basin similar in origin to a pull-apart basin.« less

Sedimentary Framework of an Inner Continental Shelf Sand-Ridge System, West-Central Florida

NASA Astrophysics Data System (ADS)

Locker, S. D.; Hine, A. C.; Wright, A. K.; Duncan, D. S.

2002-12-01

The west-central Florida inner continental shelf is a dynamic environment subject to current flows on a variety of temporal and spatial scales. A site survey program, undertaken in support of the Office of Naval Research's Mine Burial prediction program, is focused on the sedimentary framework and sediment accumulation patterns in 10-18 meters water depth. Our specific goals are to image the shallow subsurface and to monitor changes in bedform distribution patterns that coincide with physical processes studies ongoing in the area. Methods of study include side-scan sonar imaging, boomer and chirp subbottom profiling, and sedimentary facies analysis using surface sediment sampling and vibracoring. A well-defined sand-ridge system was imaged, trending oblique to the west-Florida coastline. The side-scan clearly shows that there is extensive three-dimensional structure within these large-scale NW-SE trending sedimentary bedforms. The sand ridges commonly are approximately 1 km wide and 4-8 km in length. The characteristics of these ridges are distinctly different than the sand ridges in < 8 m water that we have previously studied. Ridges in the offshore area tend to be thicker, have a flatter morphology, and exhibit fewer smaller-scale sand waves. Sand-ridge thickness ranges 2-3 meters, and typically consists of fining upward medium to fine quartz sand facies with occasional centimeter-scale coarser-grained carbonate-rich intervals. Time series investigations tracking the shift in position of the sand ridge margins have found undetectable net annual movement. However significant resuspension and bedform development accompanies high-energy events such as winter cold front passage. Thus the large-scale bedforms (sand ridges) are in a state of dynamic equilibrium with the average annual hydrodynamic regime. Repeated field surveys will focus on monitoring small-scale sedimentological and stratal framework changes that will be integrated with the quantitative process studies.

Sedimentology of new fluvial deposits on the Elwha River, Washington, USA, formed during large-scale dam removal

USGS Publications Warehouse

Draut, Amy; Ritchie, Andrew C.

2015-01-01

Removal of two dams 32 m and 64 m high on the Elwha River, Washington, USA, provided the first opportunity to examine river response to a dam removal and controlled sediment influx on such a large scale. Although many recent river-restoration efforts have included dam removal, large dam removals have been rare enough that their physical and ecological effects remain poorly understood. New sedimentary deposits that formed during this multi-stage dam removal result from a unique, artificially created imbalance between fluvial sediment supply and transport capacity. River flows during dam removal were essentially natural and included no large floods in the first two years, while draining of the two reservoirs greatly increased the sediment supply available for fluvial transport. The resulting sedimentary deposits exhibited substantial spatial heterogeneity in thickness, stratal-formation patterns, grain size and organic content. Initial mud deposition in the first year of dam removal filled pore spaces in the pre-dam-removal cobble bed, potentially causing ecological disturbance but not aggrading the bed substantially at first. During the second winter of dam removal, thicker and in some cases coarser deposits replaced the early mud deposits. By 18 months into dam removal, channel-margin and floodplain deposits were commonly >0.5 m thick and, contrary to pre-dam-removal predictions that silt and clay would bypass the river system, included average mud content around 20%. Large wood and lenses of smaller organic particles were common in the new deposits, presumably contributing additional carbon and nutrients to the ecosystem downstream of the dam sites. Understanding initial sedimentary response to the Elwha River dam removals will inform subsequent analyses of longer-term sedimentary, geomorphic and ecosystem changes in this fluvial and coastal system, and will provide important lessons for other river-restoration efforts where large dam removal is planned or proposed.

Bulding and Ornamental Stone in the History of St Petersburg Architecture

NASA Astrophysics Data System (ADS)

Bulakh, Andrey

2013-04-01

First, the Our Lady of Kazan Orthodox Cathedral and some mansions are used to demonstrate Russian stones in the architectural décor of St Petersburg, XVIII-XX cc. These rocks are granites from Vyborg and Sortavala, lime tufa from Gatchina, marbles from Ruskeala and Juven at the Ladoga Lake, Tivdian marble, Shokshian quartzite, and black aspid slate of the Onega Lake. Later German and Polish sandstones and Finnish soap stone came to the city. Second, there is given a review of rock types used in St Petersburg at XX-XXI cc. margins. They are granites, granosyenites, syenites, gneisses, marbles, limestones both from Russia and from abroad. Which ones are more usual? From what regions did Russian stone come? References: 1) A.G.Bulakh, N.B.Abakumova, J.V.Romanovsky. St Petersburg: a History in Stone. 2010. Print. House of St Petersburg State University. 173 p. 2) A.Ya. Tutakova, A.Z. Romanovskiy, A.G. Bulakh, V.I. Leer. Dimension Stone of the Leningrad Region. Granites of the Karelia Isthmus in Architecture of the Modern St Petersburg. 2011. St Petersburg. 78 p. (In Russian).

Reducing Conservatism in Aircraft Engine Response Using Conditionally Active Min-Max Limit Regulators

NASA Technical Reports Server (NTRS)

May, Ryan D.; Garg, Sanjay

2012-01-01

Current aircraft engine control logic uses a Min-Max control selection structure to prevent the engine from exceeding any safety or operational limits during transients due to throttle commands. This structure is inherently conservative and produces transient responses that are slower than necessary. In order to utilize the existing safety margins more effectively, a modification to this architecture is proposed, referred to as a Conditionally Active (CA) limit regulator. This concept uses the existing Min-Max architecture with the modification that limit regulators are active only when the operating point is close to a particular limit. This paper explores the use of CA limit regulators using a publicly available commercial aircraft engine simulation. The improvement in thrust response while maintaining all necessary safety limits is demonstrated in a number of cases.

Geomorphology of the Eastern North American Continental Margin: the role of deep sea sedimentation processes

NASA Astrophysics Data System (ADS)

Mosher, D. C.; Campbell, C.; Piper, D.; Chaytor, J. D.; Gardner, J. V.; Rebesco, M.

2016-12-01

Deep-sea sedimentation processes impart a fundamental control on the morphology of the western North Atlantic continental margin from Blake Spur to Hudson Strait. This fact is illustrated by the variable patterns of cross-margin gradients that are based on extensive new multibeam echo-sounder data in concert with subbottom profiler and seismic reflection data. Most of the continental margin has a steep (>3o) upper slope down to 1500 to 2500 m and then a gradual middle and lower slope with a general concave upward shape There is a constant interplay of deep sea sedimentation processes, but the general morphology is dictated by the dominant one. Erosion by off-shelf sediment transport in turbidity currents creating channels, gullies and canyons creates the steep upper slope. These gullies and canyons amalgamate to form singular channels that are conduits to the abyssal plain. This process results in a general seaward flattening of gradients, producing an exponentially decaying slope profile. Comparatively, sediment mass failure produces steeper upper slopes due to head scarp development and a wedging architecture to the lower slope as deposits thin in the downslope direction. This process results in either a two-segment slope, and/or a significant downslope gradient change where MTDs pinch out. Large sediment bodies deposited by contour-following currents are developed all along the margin. Blake Ridge, Sackville Spur, and Hamilton Spur are large detached drifts on disparate parts of the margin. Along their crests, they form a linear profile from the shelf to abyssal plain. Deeper portions of the US continental margin are dominated by the Chesapeake Drift and Hatteras Outer Ridge; both plastered elongate mounded drifts. Farther north, particularly on the Grand Banks margin, are plastered and separated drifts. These drifts tend to form bathymetric steps in profile, where they onlap the margin. Stacked drifts create several steps. Turbidites of the abyssal plain onlap the lowermost drift creating a significant gradient change at this juncture. Understanding the geomorphological consequences of deep sea sedimentation processes is important to extended continental shelf mapping, for example, in which gradient change is a critical metric.

Svecofennian orogeny in an evolving convergent margin setting

NASA Astrophysics Data System (ADS)

Korja, Annakaisa

2015-04-01

The dominant tectonic mode changes from extension to convergence at around 1.9 Ga in Fennoscandian. The lithological record suggests short lived subduction-related magmatic events followed by deformation and low-pressure high temperature metamorphism. At around 1.8 Ga the subduction systems seem to have stabilized implying continuous supply of oceanic lithosphere. The evolution of the convergent margin is recorded in the rock record and crustal architecture of the long lived Svecofennian orogeny (1.9-1.7 Ga). A closer look at the internal structure of the Svecofennian orogen reveals distinct regional differences. The northern and central parts of the Svecofennian orogen that have been formed during the initial accretionary phase - or compilation of the nucleus - have a thick three-layer crust and with thick mafic lower crust (10-30 km) and block-like internal architecture. Reflection profiles (FIRE1-3) image listric structures flattening on crustal scale décollement zones at the upper-middle crust and middle-upper crust boundaries. The crustal architecture together with large volumes of exposed granitoid rocks suggests spreading of the orogen and the development of an orogenic plateau west of the continental convergence boundary. The architecture is reminiscent of a large hot orogen. Within the western and southwestern part of the Svecofennian orogen (BABEL B, 1, 2, 3&4), which have been envisioned to have formed during continuous subduction phase, the crust is thinner (45-50 km) and it is hosting crustal blocks having one to two crustal layers. Layering is poorly developed in crustal blocks that are found S-SW of NE-dipping mantle reflections previously interpreted as paleo-subduction zones. Within these blocks, the crustal scale reflective structures dip NE (prowedge) or form pop-up wedges (uplifted plug) above the paleo-subduction zones. Crustal blocks with well-developed two-layer crust are located NE of the paleo-subduction zone. The architecture can be interpreted to image a series of abandoned accretion zones where the orogenic structure has developed from a young and cold orogen (BABEL 2,3&4) to a transitional (BABEL 1,6,B) one as the plate boundary is retreating during SW wards. The fast retreating rate of the subduction zone may not only have formed continental back-arc environment but may have restricted the thickening of the upper plate and the growth rate of the orogen. Altogether the architecture suggests a long-lived southwesterly retreating subduction system, with continental back-arc formation in its rear parts and well developed system of prowedge-retrowedge-uplifted plug close to a subduction conduit. Changes in the relative velocities of the upper and lower plate may have resulted in repetitive extensional and compressional phases of the orogeny as has been previously suggested for the southern part of the Svecofennian orogen.

Cenozoic Circulation History of the North Atlantic Ocean From Seismic Stratigraphy of the Newfoundland Ridge Drift Complex

NASA Astrophysics Data System (ADS)

Boyle, P. R.; Romans, B.; Norris, R. D.; Tucholke, B. E.; Swift, S. A.; Sexton, P. F.

2014-12-01

In the North Atlantic Ocean, contour-following bottom currents have eroded regional unconformities and deposited contourite drifts that exceed two km in thickness and extend for 100s of km. The character of deep-water masses that are conveyed through ocean basins by such currents influence global heat transfer and ocean-atmosphere partitioning of CO2. The Newfoundland Ridge Drift Complex lies directly under the modern Deep Western Boundary Current southeast of Newfoundland, close to the site of overturning in the northwest Atlantic Ocean and at the intersection of the warm Gulf Stream and cool Labrador surface currents. To the south are regions of the western North Atlantic basin that are influenced by southern- as well as northern-sourced bottom waters. Here, we document the evolution of North Atlantic deep-water circulation by seismic-stratigraphic analysis of the long-lived and areally extensive Newfoundland Ridge Drift Complex. IODP Expedition 342 boreholes provide age control on seismic units, allowing sedimentation patterns to be placed in a temporal framework. We find three major phases of sedimentation: pre-contourite drift (~115-50 Ma), active contourite drift (~50-2.6 Ma), and late-contourite drift (~2.6-0 Ma). Bottom-current-controlled deposition of terrigenous-rich sediment began at ~50 Ma, which correlates to the onset of a long-term global cooling trend. A further change in deep circulation near the Eocene-Oligocene transition (~30 Ma) is indicated by more focused drift sedimentation with greatly increased accumulation rates and stratal architecture dominated by mud waves. At ~2.6 Ma to present the axis of drift accumulation shifted markedly towards shallower water depths, corresponding with the onset of Northern Hemisphere ice sheets. We discuss how these reorganizations of deep circulation correlate with results of other North Atlantic seismic stratigraphic studies to the north and south.

Sedimentology and Sedimentary Dynamics of the Desmoinesian Cherokee Group, Deep Anadarko Basin, Texas Panhandle

NASA Astrophysics Data System (ADS)

Hu, N.; Loucks, R.; Frebourg, G.

2015-12-01

Understanding the spatial variability of deep-water facies is critical to deep-water research because of its revealing information about the relationship between desity flow processes and their resultant sedimentary sequences. The Cherokee Group in the Anadarko Basin, northeastern Texas Panhandle, provides an opportunity to investigate an icehouse-greenhouse Pennsylvanian hybrid system that well demonstrates the intricacies of vertical and lateral facies relationships in an unconfined fan-delta fed deep-water slope to basinal setting. The stratigraphic section ranges in thickness from 150 to 460 m. The cyclic sedimentation and foreland basin tectonics resulted in a complex stratal architecture that was sourced by multiple areas of sediment input. This investigation consists of wireline-log and core data. Five-thousand wireline logs were correlated in an area of over 9500 sq km to map out six depositional sequences that are separated by major flooding events. These events are correlative over the whole area of study. Six cores, that sample nearly the complete section, were described for lithofacies. Lithofacies are recognized based on depositional features and mineralogy:(1) Subarkose, (2) Lithicarkoses, (3) Sandy siliciclastic conglomerate, (4) Muddy calcareous conglomerate, (5) Crinoidal packstone, (6) Oodic grainstone, (7)Pelodic grainstone, (8) Ripple laminated mudrock, (9) faint laminated mudrock. The integration of isopachs of depositional sequences with the lithofacies has allowed the delineation of the spatial and temporal evolution of the slope to basin-floor system. Thin-to-thick bedded turbidites, hyperconcentrated density flow deposits (slurry beds), and debris and mud flow deposits were observed and can be used to better predicte lithofacies distributions in areas that have less data control. These mixed siliciclastic and carbonate deposits can be carrier beds for the hydrocarbons generated from the enclosing organic-rich (TOC ranges from 0.55 to 6.77wt%), dysareobic to anaerobic mudstones.

Magma-poor vs. magma-rich continental rifting and breakup in the Labrador Sea

NASA Astrophysics Data System (ADS)

Gouiza, M.; Paton, D.

2017-12-01

Magma-poor and magma-rich rifted margins show distinct structural and stratigraphic geometries during the rift to breakup period. In magma-poor margins, crustal stretching is accommodated mainly by brittle faulting and the formation of wide rift basins shaped by numerous graben and half-graben structures. Continental breakup and oceanic crust accretion are often preceded by a localised phase of (hyper-) extension where the upper mantle is embrittled, serpentinized, and exhumed to the surface. In magma-rich margins, the rift basin is narrow and extension is accompanied by a large magmatic supply. Continental breakup and oceanic crust accretion is preceded by the emplacement of a thick volcanic crust juxtaposing and underplating a moderately thinned continental crust. Both magma-poor and magma-rich rifting occur in response to lithospheric extension but the driving forces and processes are believed to be different. In the former extension is assumed to be driven by plate boundary forces, while in the latter extension is supposed to be controlled by sublithospheric mantle dynamics. However, this view fails in explaining observations from many Atlantic conjugate margins where magma-poor and magma-rich segments alternate in a relatively abrupt fashion. This is the case of the Labrador margin where the northern segment shows major magmatic supply during most of the syn-rift phase which culminate in the emplacement of a thick volcanic crust in the transitional domain along with high density bodies underplating the thinned continental crust; while the southern segment is characterized mainly by brittle extension, mantle seprentinization and exhumation prior to continental breakup. In this work, we use seismic and potential field data to describe the crustal and structural architectures of the Labrador margin, and investigate the tectonic and mechanical processes of rifting that may have controlled the magmatic supply in the different segments of the margin.

Multi-scale constraints of sediment source to sink systems in frontier basins: a forward stratigraphic modeling case study of the Levant region

NASA Astrophysics Data System (ADS)

Hawie, Nicolas; Deschamps, Remy; Granjeon, Didier; Nader, Fadi-Henri; Gorini, Christian; Müller, Carla; Montadert, Lucien; Baudin, François

2015-04-01

Recent scientific work underlined the presence of a thick Cenozoic infill in the Levant Basin reaching up to 12 km. Interestingly; restricted sedimentation was observed along the Levant margin in the Cenozoic. Since the Late Eocene successive regional geodynamic events affecting Afro-Arabia and Eurasia (collision and strike slip deformation)induced fast marginal uplifts. The initiation of local and long-lived regional drainage systems in the Oligo-Miocene period (e.g. Lebanon versus Nile) provoked a change in the depositional pattern along the Levant margin and basin. A shift from carbonate dominated environments into clastic rich systems has been observed. Through this communication we explore the importance of multi-scale constraints (i.e.,seismic, well and field data) in the quantification of the subsidence history, sediment transport and deposition of a Middle-Upper Miocene "multi-source" to sink system along the northernLevant frontier region. We prove through a comprehensive forward stratigraphic modeling workflow that the contribution to the infill of the northern Levant Basin (offshore Lebanon) is split in between proximal and more distal clastic sources as well as in situ carbonate/hemipelagic deposition. In a wider perspective this work falls under the umbrella of multi-disciplinary source to sink studies that investigate the impact of geodynamic events on basin/margin architectural evolutions, consequent sedimentary infill and thus on petroleum systems assessment.

CO2 Capillary-Trapping Processes in Deep Saline Aquifers

NASA Astrophysics Data System (ADS)

Gershenzon, Naum I.; Soltanian, Mohamadreza; Ritzi, Robert W., Jr.; Dominic, David F.

2014-05-01

The idea of reducing the Earth's greenhouse effect by sequestration of CO2 into the Earth's crust has been discussed and evaluated for more than two decades. Deep saline aquifers are the primary candidate formations for realization of this idea. Evaluation of reservoir capacity and the risk of CO2 leakage require a detailed modeling of the migration and distribution of CO2 in the subsurface structure. There is a finite risk that structural (or hydrodynamic) trapping by caprock may be compromised (e.g. by improperly abandoned wells, stratigraphic discontinuities, faults, etc.). Therefore, other trapping mechanisms (capillary trapping, dissolution, and mineralization) must be considered. Capillary trapping may be very important in providing a "secondary-seal", and is the focus of our investigation. The physical mechanism of CO2 trapping in porous media by capillary trapping incorporates three related processes, i.e. residual trapping, trapping due to hysteresis of the relative permeability, and trapping due to hysteresis of the capillary pressure. Additionally CO2 may be trapped in heterogeneous media due to difference in capillary pressure entry points for different materials. The amount of CO2 trapped by these processes is a complicated nonlinear function of the spatial distribution of permeability, permeability anisotropy, capillary pressure, relative permeability of brine and CO2, permeability hysteresis and residual gas saturation (as well as the rate, total amount and placement of injected CO2). Geological heterogeneities essentially affect the dynamics of a CO2 plume in subsurface environments. Recent studies have led to new conceptual and quantitative models for sedimentary architecture in fluvial deposits over a range of scales that are relevant to the performance of some deep saline reservoirs [1, 2]. We investigated how the dynamics of a CO2 plume, during and after injection, is influenced by the hierarchical and multi-scale stratal architecture in such reservoirs. The results strongly suggest that representing these small scales features, and representing how they are organized within a hierarchy of larger-scale features, is critical to understanding capillary trapping processes. References [1] Bridge, J.S. (2006), Fluvial facies models: Recent developments, in Facies Models Revisited, SEPM Spec. Publ., 84, edited by H. W. Posamentier and R. G. Walker, pp. 85-170, Soc. for Sediment. Geol. (SEPM), Tulsa, Okla [2] Ramanathan, R., A. Guin, R.W. Ritzi, D.F. Dominic, V.L. Freedman, T.D. Scheibe, and I.A. Lunt (2010), Simulating the heterogeneity in channel belt deposits: Part 1. A geometric-based methodology and code, Water Resources Research, v. 46, W04515.

Economic tools to promote transparency and comparability in the Paris Agreement

NASA Astrophysics Data System (ADS)

Aldy, Joseph; Pizer, William; Tavoni, Massimo; Reis, Lara Aleluia; Akimoto, Keigo; Blanford, Geoffrey; Carraro, Carlo; Clarke, Leon E.; Edmonds, James; Iyer, Gokul C.; McJeon, Haewon C.; Richels, Richard; Rose, Steven; Sano, Fuminori

2016-11-01

The Paris Agreement culminates a six-year transition towards an international climate policy architecture based on parties submitting national pledges every five years. An important policy task will be to assess and compare these contributions. We use four integrated assessment models to produce metrics of Paris Agreement pledges, and show differentiated effort across countries: wealthier countries pledge to undertake greater emission reductions with higher costs. The pledges fall in the lower end of the distributions of the social cost of carbon and the cost-minimizing path to limiting warming to 2 °C, suggesting insufficient global ambition in light of leaders’ climate goals. Countries’ marginal abatement costs vary by two orders of magnitude, illustrating that large efficiency gains are available through joint mitigation efforts and/or carbon price coordination. Marginal costs rise almost proportionally with income, but full policy costs reveal more complex regional patterns due to terms of trade effects.

Rift-drift transition in the Dangerous Grounds, South China Sea

NASA Astrophysics Data System (ADS)

Peng, Xi; Shen, Chuanbo; Mei, Lianfu; Zhao, Zhigang; Xie, Xiaojun

2018-04-01

The South China Sea (SCS) has a long record of rifting before and after subsequent seafloor spreading, affecting the wide continent of the Dangerous Grounds, and its scissor-shape opening manner results in the rifting structures that vary along this margin. Some 2000 km of regional multichannel seismic data combined with borehole and dredge data are interpreted to analyze the multistage rifting process, structural architecture and dynamic evolution across the entire Dangerous Grounds. Key sequence boundaries above the Cenozoic basement are identified and classified into the breakup unconformity and the rift end unconformity, which consist of the rift-related unconformities. Reflector T70 in the east of the Dangerous Grounds represents the breakup unconformity, which is likely corresponding to the spreading of the East Subbasin. T60 formed on the top of carbonate platform is time equivalent to the spreading of the Southwest Subbasin, marking the breakup unconformity of the central Dangerous Grounds. The termination of the spreading of the SCS is manifested by the rift end unconformity of T50 in the southwest and the final rift occurring in the northwest of the Dangerous Grounds is postponed to the rift end unconformity of T40. On the basis of the stratigraphic and structural analysis, distinct segments in the structural architecture of the syn-rift units and the ages of rift-drift transition show obvious change from the proximal zone to the distal zone. Three domains, which are the Reed Bank-Palawan Rift domain, the Dangerous Grounds Central Detachment domain and Nam Con Son Exhumation domain, reflect the propagation of the margin rifting developed initially by grabens formed by high angle faults, then large half-grabens controlled by listric faults and detachments and finally rotated fault blocks in the hyper-extended upper crust associated with missing lower crust or exhumed mantle revealing a migration and stepwise rifting process in the south margin of the SCS.

3D numerical simulations of multiphase continental rifting

NASA Astrophysics Data System (ADS)

Naliboff, J.; Glerum, A.; Brune, S.

2017-12-01

Observations of rifted margin architecture suggest continental breakup occurs through multiple phases of extension with distinct styles of deformation. The initial rifting stages are often characterized by slow extension rates and distributed normal faulting in the upper crust decoupled from deformation in the lower crust and mantle lithosphere. Further rifting marks a transition to higher extension rates and coupling between the crust and mantle lithosphere, with deformation typically focused along large-scale detachment faults. Significantly, recent detailed reconstructions and high-resolution 2D numerical simulations suggest that rather than remaining focused on a single long-lived detachment fault, deformation in this phase may progress toward lithospheric breakup through a complex process of fault interaction and development. The numerical simulations also suggest that an initial phase of distributed normal faulting can play a key role in the development of these complex fault networks and the resulting finite deformation patterns. Motivated by these findings, we will present 3D numerical simulations of continental rifting that examine the role of temporal increases in extension velocity on rifted margin structure. The numerical simulations are developed with the massively parallel finite-element code ASPECT. While originally designed to model mantle convection using advanced solvers and adaptive mesh refinement techniques, ASPECT has been extended to model visco-plastic deformation that combines a Drucker Prager yield criterion with non-linear dislocation and diffusion creep. To promote deformation localization, the internal friction angle and cohesion weaken as a function of accumulated plastic strain. Rather than prescribing a single zone of weakness to initiate deformation, an initial random perturbation of the plastic strain field combined with rapid strain weakening produces distributed normal faulting at relatively slow rates of extension in both 2D and 3D simulations. Our presentation will focus on both the numerical assumptions required to produce these results and variations in 3D rifted margin architecture arising from a transition from slow to rapid rates of extension.

The Acoustic Signature of Glaciated Margins

NASA Astrophysics Data System (ADS)

Newton, A. M. W.; Huuse, M.

2016-12-01

As climate warms it has become increasingly clear that, in order to fully understand how it might evolve in the future, we need to look for examples of how climate has changed in the past. The Late Cenozoic history of the Arctic Ocean and its surrounding seas has been dominated by glacial-interglacials cycles. This has resulted in major environmental changes in relative sea levels, ice volumes, sea ice conditions, and ocean circulation as marine and terrestrially-based ice sheets waxed and waned. In this work, the acoustic signatures of several glaciated margins in the Northern Hemisphere are investigated and compared. This includes: NW Greenland, West Greenland, East Greenland, mid-Norway, Northern Norway, and the North Sea. These shelf successions preserve a geomorphological record of multiple glaciations and are imaged using seismic reflection data. To date, the majority of work in these areas has tended to focus on the most recent glaciations, which are well known. Here, the focus of the work is to look at the overall stratigraphic setting and how it influences (and is influenced by) the evolution of ice sheets throughout the glacial succession. Landform records are imaged using seismic data to provide a long-term insight into the styles of glaciation on each margin and what relation this may have had on climate, whilst the stratigraphic architectures across each site demonstrate how the inherited geology and tectonic setting can provide a fundamental control on the ice sheet and depositional styles. For example, Scoresby Sund is characterised by significant aggradation that is likely related to subsidence induced by lithospheric cooling rather than rapid glacial deposition, whilst the subsidence of the mid-Norwegian margin can be related to rapid glacial deposition and trapping of sediments behind inversion structures such as the Helland-Hansen Arch. The insights from this multi-margin study allow for regional, basin-wide, glaciological records to be developed and to investigate how marine, marginal-marine, and grounded glacial signatures vary across margins with different geological histories and whether these margins evolved with any synchronicity.

The long-term evolution of the Congo deep-sea fan: A basin-wide view of the interaction between a giant submarine fan and a mature passive margin (ZaiAngo project)

NASA Astrophysics Data System (ADS)

Anka, Zahie; Séranne, Michel; Lopez, Michel; Scheck-Wenderoth, Magdalena; Savoye, Bruno

2009-05-01

We have integrated the relatively unknown distal domains of the Lower Congo basin, where the main depocenters of the Congo submarine fan are located, with the better-constrained successions on the shelf and upper slope, through the analysis of thousands of km of 2D seismic reflection profiles off-shore the Congo-Angola passive margin. The basin architecture is depicted by two ca. 800-km-long regional cross sections through the northern (Congo) and southern (Angola) margin. A large unit deposited basinward of the Aptian salt limit is likely to be the abyssal-plain equivalent of the upper-Cretaceous carbonate shelf that characterized the first post-rift deposits in West-equatorial African margins. A latest-Turonian shelf-deepening event is recorded in the abyssal plain as a long period (Coniacian-Eocene) of condensed sedimentation and basin starvation. The onset of the giant Tertiary Congo deep-sea fan in early Oligocene following this event reactivates the abyssal plain as the main depocenter of the basin. The time-space partitioning of sedimentation within the deep-sea fan results from the interplay among increasing sediment supply, margin uplift, rise of the Angola salt ridge, and canyon incision throughout the Neogene. Oligocene-early Miocene turbidite sedimentation occurs mainly in NW-SE grabens and ponded inter-diapir basins on the southern margin (Angola). Seaward tilting of the margin and downslope salt withdrawal activates the up-building of the Angola escarpment, which leads to a northward (Congo) shift of the transfer zones during late Miocene. Around the Miocene-Pliocene boundary, the incision of the Congo submarine canyon confines the turbidite flows and drives a general basinward progradation of the submarine fan into the abyssal plain The slope deposition is dominated by fine-grained hemipelagic deposits ever since. Results from this work contribute to better understand the signature in the ultra-deep deposits of processes acting on the continental margin as well as the basin-wide sediment redistribution in areas of high river input.

Architecture and reservoir quality of low-permeable Eocene lacustrine turbidite sandstone from the Dongying Depression, East China

NASA Astrophysics Data System (ADS)

Munawar, Muhammad Jawad; Lin, Chengyan; Chunmei, Dong; Zhang, Xianguo; Zhao, Haiyan; Xiao, Shuming; Azeem, Tahir; Zahid, Muhammad Aleem; Ma, Cunfei

2018-05-01

The architecture and quality of lacustrine turbidites that act as petroleum reservoirs are less well documented. Reservoir architecture and multiscale heterogeneity in turbidites represent serious challenges to production performance. Additionally, establishing a hierarchy profile to delineate heterogeneity is a challenging task in lacustrine turbidite deposits. Here, we report on the turbidites in the middle third member of the Eocene Shahejie Formation (Es3), which was deposited during extensive Middle to Late Eocene rifting in the Dongying Depression. Seismic records, wireline log responses, and core observations were integrated to describe the reservoir heterogeneity by delineating the architectural elements, sequence stratigraphic framework and lithofacies assemblage. A petrographic approach was adopted to constrain microscopic heterogeneity using an optical microscope, routine core analyses and X-ray diffraction (XRD) analyses. The Es3m member is interpreted as a sequence set composed of four composite sequences: CS1, CS2, CS3 and CS4. A total of forty-five sequences were identified within these four composite sequences. Sand bodies were mainly deposited as channels, levees, overbank splays, lobes and lobe fringes. The combination of fining-upward and coarsening-upward lithofacies patterns in the architectural elements produces highly complex composite flow units. Microscopic heterogeneity is produced by diagenetic alteration processes (i.e., feldspar dissolution, authigenic clay formation and quartz cementation). The widespread kaolinization of feldspar and mobilization of materials enhanced the quality of the reservoir by producing secondary enlarged pores. In contrast, the formation of pore-filling authigenic illite and illite/smectite clays reduced its permeability. Recovery rates are higher in the axial areas and smaller in the marginal areas of architectural elements. This study represents a significant insight into the reservoir architecture and heterogeneity of lacustrine turbidites, and the understanding of compartmentalization and distribution of high-quality sand reservoirs can be applied to improve primary and secondary production in these fields.

A revised subduction inception model to explain the Late Cretaceous, doubly vergent orogen in the pre-collisional western Tethys: evidences from the Northern Apennine

NASA Astrophysics Data System (ADS)

Meneghini, Francesca; Marroni, Michele; Pandolfi, Luca

2017-04-01

Orogenic processes are widely demonstrated to be strongly controlled by inherited structures. The paleogeography of the converging margins, and the tectonic processes responsible for their configuration, will influence the location of subduction initiation, the distribution of deformation between upper and lower plate, the shape of the accretionary prism and of the subsequent orogeny, through controlling the development of single or doubly-vergent orogens, and, as a corollary, the modality of exhumation of metamorphosed units. The "alpine age" collisional belts of the Mediterranean area are characterized by tangled architectures derived from the overlapping of several deformation events related to a multiphase, long history that comprises not only the collision of continental margins, but that can be regarded as an heritage of both the rifting-related configuration of the continental margins, and the subduction-related structures. The Northern Apennines is a segment of these collisional belts that originated by the Late Cretaceous-Middle Eocene closure of the northern branch of the western Tethys, and the subsequent Late Eocene-Early Oligocene continental collision between the Europe and Adria plates. Due to a different configuration of the paired Adria and Europe continental margins, inherited from a rifting phase dominated by asymmetric, simple-shear kinematics, the Northern Apennines expose a complex groups of units, referred to as Ligurian Units, that record the incorporation into the subduction factory of either fragments of the Ligure-Piemontese oceanic domain (i.e. Internal Ligurian Units), and various portions of the thinned Adria margin (i.e. External Ligurian Units), describable as an Ocean-Continent Transition Zone (OCTZ). The structural relationships between these groups of Units are crucial for the definition of the pre-collisional evolution of the belt and have been the subject of big debates in the literature, together with the location and orientation of subduction initiation. We have reviewed the ages and characteristics of the tectono-metamorphic events recorded in both the External and Internal Ligurian Units. Deformation and metamorphism in the External Ligurian Units pre-dates the subduction-related metamorphism recorded in the ocean-derived Internal Ligurian Units. We thus propose that closure of the Ligure-Piemontese branch of the western Tethys occurred through a subduction that nucleated inside the OCTZ of Adria, instead of localizing at the boundary between the oceanic basin and the Adria margin, and developed a doubly-vergent prism fed firstly by both continental extensional allochthons and ocean-derived rocks from the OCTZ, and only after by rocks and sediments from the oceanic realm. We believe that this revised location of the inception of subduction, and the subsequent pre-collisional architecture, considered as inherited from the rifting and the oceanic opening phases, allow reconciling most of the controversies on the geodynamic evolution of the Apenninic orogeny, prior to collision.

Depositional architecture and evolution of the Late Miocene slope channel-fan-system in the northeastern shelf-margin of South China Sea

NASA Astrophysics Data System (ADS)

Jiang, Jing; Lin, Changsong; Zhang, Zhongtao; Tian, Hongxun; Tao, Ze; Liu, Hanyao

2016-04-01

The Upper Miocene in the Pearl River Mouth Basin of northwestern shelf-margin of South China Sea Basin contains a series of slope channel - fan systems. Their depositional architecture and evolution are documented in this investigation based on an integrated analysis of cores, logs, and seismic data. Four depositional-palaeogeomorphological elements have been identified in the slope channel-fan systems as follows: broad, shallow and unconfined or partly confined outer-shelf to shelf-break channels; deeply incised and confined unidirectionally migrating slope channels; broad or U-shaped, unconfined erosional-depositional channels; frontal splays-lobes and nonchannelized sheets. The slope channels are mostly oriented NW-SE, which migrated unidirectionally northeastwards and intensively eroded almost the whole shelf-slope zone. The channel infillings are mainly mudstones, interbedded with siltstones. They might be formed by gravity flow erosion as bypassing channels. They were filled with limited gravity flow sediments at the base and mostly filled with lateral accretionary packages of bottom current deposits. At the end of the channels, a series of small-scale slope fans developed and coalesced into fan aprons along the base of the slope. The unconfined erosional-depositional channels at the upper parts of the fan-apron-systems display compound infill patterns, and commonly have concave erosional bases and convex tops. The frontal splays-lobes representing middle to distal deposits of fan-apron-systems have flat-mounded or gull-wing geometries, and the internal architectures include bidirectional downlap, progradation, and chaotic infillings. The distal nonchannelized turbidite sheets are characterized by thin-bedded, parallel to sub-parallel sheet-like geometries. Three major unconformities or obvious erosional surfaces in the channel-fan systems of the Upper Miocene are recognized, and indicate the falling of sea-level. The depositional architecture of sequences varies from the upper slope to the slope base transitional to basin plain. The basal erosion and the unidirectionally migrating characters of the slope channels were supposed to be the result of the interaction of bottom currents and gravity flows. The intensive development of the channel-fan systems over the shelf slope might be related to the Dongsha Tectonic uplift which may resulted in stepped slope and concomitantly intensified gravity flow in the study area in Late Miocene.

Geomorphological and sedimentary processes of the glacially influenced northwestern Iberian continental margin and abyssal plains

NASA Astrophysics Data System (ADS)

Llave, Estefanía; Jané, Gloria; Maestro, Adolfo; López-Martínez, Jerónimo; Hernández-Molina, F. Javier; Mink, Sandra

2018-07-01

The offshore region of northwestern Iberia offers an opportunity to study the impacts of along-slope processes on the morphology of a glacially influenced continental margin, which has traditionally been conceptually characterised by predominant down-slope sedimentary processes. High-resolution multibeam bathymetry, acoustic backscatter and ultrahigh-resolution seismic reflection profile data are integrated and analysed to describe the present-day and recent geomorphological features and to interpret their associated sedimentary processes. Seventeen large-scale seafloor morphologies and sixteen individual echo types, interpreted as structural features (escarpments, marginal platforms and related fluid escape structures) and depositional and erosional bedforms developed either by the influence of bottom currents (moats, abraded surfaces, sediment waves, contourite drifts and ridges) or by gravitational features (gullies, canyons, slides, channel-levee complexes and submarine fans), are identified for the first time in the study area (spanning 90,000 km2 and water depths of 300 m to 5 km). Different types of slope failures and turbidity currents are mainly observed on the upper and lower slopes and along submarine canyons and deep-sea channels. The middle slope morphologies are mostly determined by the actions of bottom currents (North Atlantic Central Water, Mediterranean Outflow Water, Labrador Sea Water and North Atlantic Deep Water), which thereby define the margin morphologies and favour the reworking and deposition of sediments. The abyssal plains (Biscay and Iberian) are characterised by pelagic deposits and channel-lobe systems (the Cantabrian and Charcot), although several contourite features are also observed at the foot of the slope due to the influence of the deepest water masses (i.e., the North Atlantic Deep Water and Lower Deep Water). This work shows that the study area is the result of Mesozoic to present-day tectonics (e.g. the marginal platforms and structural highs). Therefore, tectonism constitutes a long-term controlling factor, whereas the climate, sediment supply and bottom currents play key roles in the recent short-term architecture and dynamics. Moreover, the recent predominant along-slope sedimentary processes observed in the studied northwestern Iberian Margin represent snapshots of the progressive stages and mixed deep-water system developments of the marginal platforms on passive margins and may provide information for a predictive model of the evolution of other similar margins.

Fault evolution in the Potiguar rift termination, equatorial margin of Brazil

NASA Astrophysics Data System (ADS)

de Castro, D. L.; Bezerra, F. H. R.

2015-02-01

The transform shearing between South American and African plates in the Cretaceous generated a series of sedimentary basins on both plate margins. In this study, we use gravity, aeromagnetic, and resistivity surveys to identify architecture of fault systems and to analyze the evolution of the eastern equatorial margin of Brazil. Our study area is the southern onshore termination of the Potiguar rift, which is an aborted NE-trending rift arm developed during the breakup of Pangea. The basin is located along the NNE margin of South America that faces the main transform zone that separates the North and the South Atlantic. The Potiguar rift is a Neocomian structure located at the intersection of the equatorial and western South Atlantic and is composed of a series of NE-trending horsts and grabens. This study reveals new grabens in the Potiguar rift and indicates that stretching in the southern rift termination created a WNW-trending, 10 km wide, and ~ 40 km long right-lateral strike-slip fault zone. This zone encompasses at least eight depocenters, which are bounded by a left-stepping, en echelon system of NW-SE- to NS-striking normal faults. These depocenters form grabens up to 1200 m deep with a rhomb-shaped geometry, which are filled with rift sedimentary units and capped by postrift sedimentary sequences. The evolution of the rift termination is consistent with the right-lateral shearing of the equatorial margin in the Cretaceous and occurs not only at the rift termination but also as isolated structures away from the main rift. This study indicates that the strike-slip shearing between two plates propagated to the interior of one of these plates, where faults with similar orientation, kinematics, geometry, and timing of the major transform are observed. These faults also influence rift geometry.

How the structural architecture of the Eurasian continental margin affects the structure, seismicity, and topography of the south central Taiwan fold-and-thrust belt

NASA Astrophysics Data System (ADS)

Brown, Dennis; Alvarez-Marron, Joaquina; Biete, Cristina; Kuo-Chen, Hao; Camanni, Giovanni; Ho, Chun-Wei

2017-07-01

Studies of mountain belts worldwide show that along-strike changes are common in their foreland fold-and-thrust belts. These are typically caused by processes related to fault reactivation and/or fault focusing along changes in sedimentary sequences. The study of active orogens, like Taiwan, can also provide insights into how these processes influence transient features such as seismicity and topography. In this paper, we trace regional-scale features from the Eurasian continental margin in the Taiwan Strait into the south central Taiwan fold-and-thrust belt. We then present newly mapped surface geology, P wave velocity maps and sections, seismicity, and topography data to test the hypothesis of whether or not these regional-scale features of the margin are contributing to along-strike changes in structural style, and the distribution of seismicity and topography in this part of the Taiwan fold-and-thrust belt. These data show that the most important along-strike change takes place at the eastward prolongation of the upper part of the margin necking zone, where there is a causal link between fault reactivation, involvement of basement in the thrusting, concentration of seismicity, and the formation of high topography. On the area correlated with the necking zone, the strike-slip reactivation of east northeast striking extensional faults is causing sigmoidal offset of structures and topography along two main zones. Here basement is not involved in the thrusting; there is weak focusing of seismicity and localized development of topography. We also show that there are important differences in structure, seismicity, and topography between the margin shelf and its necking zone.

Origin and dynamics of depositionary subduction margins

USGS Publications Warehouse

Vannucchi, Paola; Morgan, Jason P.; Silver, Eli; Kluesner, Jared W.

2016-01-01

Here we propose a new framework for forearc evolution that focuses on the potential feedbacks between subduction tectonics, sedimentation, and geomorphology that take place during an extreme event of subduction erosion. These feedbacks can lead to the creation of a “depositionary forearc,” a forearc structure that extends the traditional division of forearcs into accretionary or erosive subduction margins by demonstrating a mode of rapid basin accretion during an erosive event at a subduction margin. A depositionary mode of forearc evolution occurs when terrigenous sediments are deposited directly on the forearc while it is being removed from below by subduction erosion. In the most extreme case, an entire forearc can be removed by a single subduction erosion event followed by depositionary replacement without involving transfer of sediments from the incoming plate. We need to further recognize that subduction forearcs are often shaped by interactions between slow, long-term processes, and sudden extreme events reflecting the sudden influences of large-scale morphological variations in the incoming plate. Both types of processes contribute to the large-scale architecture of the forearc, with extreme events associated with a replacive depositionary mode that rapidly creates sections of a typical forearc margin. The persistent upward diversion of the megathrust is likely to affect its geometry, frictional nature, and hydrogeology. Therefore, the stresses along the fault and individual earthquake rupture characteristics are also expected to be more variable in these erosive systems than in systems with long-lived megathrust surfaces.

From hyperextended rift to convergent margin types: mapping the outer limit of the extended Continental Shelf of Spain in the Galicia area according UNCLOS Art. 76

NASA Astrophysics Data System (ADS)

Somoza, Luis; Medialdea, Teresa; Vázquez, Juan T.; González, Francisco J.; León, Ricardo; Palomino, Desiree; Fernández-Salas, Luis M.; Rengel, Juan

2017-04-01

Spain presented on 11 May 2009 a partial submission for delimiting the extended Continental Shelf in respect to the area of Galicia to the Commission on the Limits of the Continental Shelf (CLCS). The Galicia margin represents an example of the transition between two different types of continental margins (CM): a western hyperpextended margin and a northern convergent margin in the Bay of Biscay. The western Galicia Margin (wGM 41° to 43° N) corresponds to a hyper-extended rifted margin as result of the poly-phase development of the Iberian-Newfoundland conjugate margin during the Mesozoic. Otherwise, the north Galicia Margin (nGM) is the western end of the Cenozoic subduction of the Bay of Biscay along the north Iberian Margin (NIM) linked to the Pyrenean-Mediterranean collisional belt Following the procedure established by the CLCS Scientific and Technical Guidelines (CLCS/11), the points of the Foot of Slope (FoS) has to be determined as the points of maximum change in gradient in the region defined as the Base of the continental Slope (BoS). Moreover, the CLCS guidelines specify that the BoS should be contained within the continental margin (CM). In this way, a full-coverage multibeam bathymetry and an extensive dataset of up 4,736 km of multichannel seismic profiles were expressly obtained during two oceanographic surveys (Breogham-2005 and Espor-2008), aboard the Spanish research vessel Hespérides, to map the outer limit of the CM.In order to follow the criteria of the CLCS guidelines, two types of models reported in the CLCS Guidelines were applied to the Galicia Margin. In passive margins, the Commission's guidelines establish that the natural prolongation is based on that "the natural process by which a continent breaks up prior to the separation by seafloor spreading involves thinning, extension and rifting of the continental crust…" (para. 7.3, CLCS/11). The seaward extension of the wGM should include crustal continental blocks and the so-called Peridotite Ridge (PR), composed by serpentinized exhumed continental mantle. Thus, the PR should be regarded as a natural component of the continental margin since these seafloor highs were formed by hyperextension of the margin. Regarding convergent margins, the architecture of the nGM can be classified according the CLCS/11 as a "poor- or non-accretionary convergent continental margin" characterized by a poorly developed accretionary wedge, which is composed of: a large sedimentary apron mainly formed by large slumps and thrust wedges of igneous (ophiolitic/continental) body overlying subducting oceanic crust (Fig. 6.1B, CLCS/11). According to para. 6.3.6. (CLCS/11), the seaward extent of this type of continental convergent margins is defined by the seaward edge of the accretionary wedge. Applying this definition, the seaward extent of the margin is defined by the outer limit of the ophiolitic deformed body that marks the edge of the accretionary wedge. These geological criteria were strictly applied for mapping the BoS region, where the FoS were determinate by using the maximum change in gradient within this mapped region. Acknowledgments: Project for the Extension of the Spanish Continental according UNCLOS (CTM2010-09496-E) and Project CTM2016-75947-R

Exploring the Use of Model-Based Systems Engineering (MBSE) to Develop Systems Architectures in Naval Ship Design

DTIC Science & Technology

2010-06-01

data such as the NSMB B-series, or be based on hydrodynamic (lifting line) predict ions. The power including still air drag and any margin that is...Provide Fuel Function 3.6 Fuel Oil System Component REQ.1.4 Fuel Efficiency Requirement 1.1 Generate Mechanical En... Function 1.1 Prime Mover Component...3.3 Provide Lubrication Function 3.7 Lube Oil System Component 3.4 Provide Cooling Water Function 3.3 Cooling System Component 3.5 Provide Combust ion

Predictive Modeling for NASA Entry, Descent and Landing Missions

NASA Technical Reports Server (NTRS)

Wright, Michael

2016-01-01

Entry, Descent and Landing (EDL) Modeling and Simulation (MS) is an enabling capability for complex NASA entry missions such as MSL and Orion. MS is used in every mission phase to define mission concepts, select appropriate architectures, design EDL systems, quantify margin and risk, ensure correct system operation, and analyze data returned from the entry. In an environment where it is impossible to fully test EDL concepts on the ground prior to use, accurate MS capability is required to extrapolate ground test results to expected flight performance.

Tectono-sedimentary evolution of the eastern Gulf of Aden conjugate passive margins: Narrowness and asymmetry in oblique rifting context

NASA Astrophysics Data System (ADS)

Nonn, Chloé; Leroy, Sylvie; Khanbari, Khaled; Ahmed, Abdulhakim

2017-11-01

Here, we focus on the yet unexplored eastern Gulf of Aden, on Socotra Island (Yemen), Southeastern Oman and offshore conjugate passive margins between the Socotra-Hadbeen (SHFZ) and the eastern Gulf of Aden fracture zones. Our interpretation leads to onshore-offshore stratigraphic correlation between the passive margins. We present a new map reflecting the boundaries between the crustal domains (proximal, necking, hyper-extended, exhumed mantle, proto-oceanic and oceanic domains) and structures using bathymetry, magnetic surveys and seismic reflection data. The most striking result is that the magma-poor conjugate margins exhibit asymmetrical architecture since the thinning phase (Upper Rupelian-Burdigalian). Their necking domains are sharp ( 40-10 km wide) and their hyper-extended domains are narrow and asymmetric ( 10-40 km wide on the Socotra margin and 50-80 km wide on the Omani margin). We suggest that this asymmetry is related to the migration of the rift center producing significant lower crustal flow and sequential faulting in the hyper-extended domain. Throughout the Oligo-Miocene rifting, far-field forces dominate and the deformation is accommodated along EW to N110°E northward-dipping low angle normal faults. Convection in the mantle near the SHFZ may be responsible of change in fault dip polarity in the Omani hyper-extended domain. We show the existence of a northward-dipping detachment fault formed at the beginning of the exhumation phase (Burdigalien). It separates the northern upper plate (Oman) from southern lower plate (Socotra Island) and may have generated rift-induced decompression melting and volcanism affecting the upper plate. We highlight multiple generations of detachment faults exhuming serpentinized subcontinental mantle in the ocean-continent transition. Associated to significant decompression melting, final detachment fault may have triggered the formation of a proto-oceanic crust at 17.6 Ma and induced late volcanism up to 10 Ma. Finally, the setting up of a steady-state oceanic spreading center occurs at 17 Ma.

Linking Observations of Dynamic Topography from Oceanic and Continental Realms around Australia

NASA Astrophysics Data System (ADS)

Czarnota, K.; Hoggard, M. J.; White, N.; Winterbourne, J.

2012-04-01

In the last decade, there has been growing interest in predicting the spatial and temporal evolution of dynamic topography (i.e. the surface manifestation of mantle convection). By directly measuring Neogene and Quaternary dynamic topography around Australia's passive margins we assess the veracity of these predictions and the interplay between mantle convection and plate motion. We mapped the present dynamic topography by carefully measuring residual topography of oceanic lithosphere adjacent to passive margins. This map provides a reference with respect to which the relative record of vertical motions, preserved within the stratigraphic architecture of the margins, can be interpreted. We carefully constrained the temporal record of vertical motions along Australia's Northwest Shelf by backstripping Neogene carbonate clinoform rollover trajectories in order to minimise paleobathymetric errors. Elsewhere, we compile temporal constraints from published literature. Three principal insights emerge from our analysis. First, the present-day drawn-down residual topography of Australia, cannot be approximated by a regional tilt down towards the northeast, as previously hypothesised. The south-western and south-eastern corners of Australia are at negligible to slightly positive residual topography which slopes down towards Australia's northern margin and the Great Australian Bight. Secondly, the record of passive margin subsidence suggests drawdown across northern Australia commenced synchronously at 8±2 Ma. The amplitude of this synchronous drawdown corresponds to the amplitude of oceanic residual topography, indicating northern Australia was at an unperturbed dynamic elevation until drawdown commenced. The synchronicity of this subsidence suggests that the Australian plate has not been affected by a southward propagating wave of drawdown, despite Australia's rapid northward motion towards the subduction realm in south-east Asia. In contrast, it appears the mantle anomaly responsible for this drawdown is a relatively young, long-wavelength feature. Thirdly, there is an apparent mismatch between the current drawdown of oceanic lithosphere observed along Australia's southern margin and the onshore record of Cenozoic uplift. This disparity we attribute to the region undergoing recent uplift from a position of dynamic drawdown.

Geodynamic evolution and sedimentary infill of the northern Levant Basin: A source to sink-perspective

NASA Astrophysics Data System (ADS)

Hawie, N.

2013-12-01

Nicolas Hawie a,b,c (nicolas.hawie@upmc.fr) Didier Granjeon c (didier.granjeon@ifpen.fr) Christian Gorini a,b (christian.gorini@upmc.fr) Remy Deschamps c (remy.deschamps@ifpen.fr) Fadi H. Nader c (fadi-henri.nader@ifpen.fr) Carla Müller Delphine Desmares f (delphine.desmares@upmc.fr) Lucien Montadert e (lucien.montadert@beicip.com) François Baudin a (francois.baudin@upmc.fr) a UMR 7193 Institut des Sciences de la Terre de Paris, Université Pierre et Marie Curie/ Univ. Paris 06, case 117. 4, place Jussieu 75252 Paris Cedex 05, France b iSTEP, UMR 7193, CNRS, F-75005, Paris, France c IFP Energies nouvelles, 1-4 avenue du Bois Préau 92852 Rueil Malmaison Cedex, France d UMR 7207, Centre de Recherche sur la Paleobiodiversité et les Paleoenvironnements. Université Pierre et Marie Curie, Tour 46-56 5ème. 4, place Jussieu 75252 Paris Cedex 05, France e Beicip Franlab, 232 Av. Napoléon Bonaparte, 95502 Rueil-Malmaison, France Sedimentological and biostratigraphic investigations onshore Lebanon coupled with 2D offshore reflection seismic data allowed proposing a new Mesozoic-Present tectono-stratigraphic framework for the northern Levant Margin and Basin. The seismic interpretation supported by in-depth facies analysis permitted to depict the potential depositional environments offshore Lebanon as no well has yet been drilled. The Levant region has been affected by successive geodynamic events that modified the architecture of its margin and basin from a Late Triassic to Middle Jurassic rift into a Late Cretaceous subduction followed by collision and Miocene-Present strike slip motion. The interplay between major geodynamic events as well as sea level fluctuations impacted on the sedimentary infill of the basin. During Jurassic and Cretaceous, the Levant Margin is dominated by the aggradation of a carbonate platform while deepwater mixed-systems prevailed in the basin. During the Oligo-Miocene, three major sedimentary pathways are expected to drive important quantities of clastic material into the Levant Basin: (1) the marginal canyons along the Levant Margin, (2) the Latakia region and the Palmyrides Basin (Syria) and (3) the Red Sea area and Nile Delta. Regional drainage system analysis was performed to estimate the contribution to the infill of the basin of the different sediment sources, and in particular, to estimate erosion of Nubian siliciclastic material, granitic Red Sea rift shoulders and Arabian Shield. A numerical stratigraphic forward model, Dionisos, was used to test these source-to-sink assumptions; a sensitivity analysis was then performed to understand better the impact of the different geodynamic and stratigraphic scenarios on the architecture and sedimentary infill of the Levant Basin, and thus on the expected petroleum systems of this frontier basin

Three-dimensional facies architecture of the Salem Limestone (middle Mississippian), Eastern Margin of Illinois basin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nadeem, A.; Keith, B.D.; Thompson, T.A.

Mapping of sedimentary surfaces in the Middle Mississippian Salem Limestone exposed on sawed quarry walls in south-central Indiana has revealed a hierarchy of depositional units representative of the extremely dynamic hydrographic regime of the upper shoreface zone. The depositional units on the scale of microform and mesoform are represented by the microfacies and the facies respectively. Based on their hierarchy, genetically related depositional units and associated bounding surfaces were grouped together to construct four architectural packages (APs) of the scale of mesoforms. AP-I is dominantly an echinoderm- and bryozoan-rich grainstone and consists of bedforms ranging from small ripples bounded bymore » first-order surfaces to two- and three- dimensional megaripples bounded by the second-order surfaces. It formed as part of a giant ramp (asymmetric wavefield) within the intrashoal channel setting. AP-II, also a skeletal grainstone, is a complex of giant sandwaves that moved into the area under the infulence of a storm and partly filled the basal channel form of AP-I. Large avalanche foresets with tangential toesets prevail. AP-III is a dark-gray spatially discontinuous skeletal grainstone to packstone that laterally grades into a skeletal packstone to wackestone. It locally developed overhangs, rips-ups, and hardground on its upper surface. AP-IV is a skeletal and oolitic grainstone formed of tabular two-dimensional megaripples (planar cross-beds) and three-dimensional oscillatory megaripples (trough cross-beds). These architectural packages based on the bedform architecture and micro-and mesoscale compositional changes can be used to characterize micro-, meso, and macroscale heterogeneities. Models of facies architecture from this and similar outcrop studies can be applied to the subsurface Salem reservoirs in the Illinois Basin using cores.« less

Greek classicism in living structure? Some deductive pathways in animal morphology.

PubMed

Zweers, G A

1985-01-01

Classical temples in ancient Greece show two deterministic illusionistic principles of architecture, which govern their functional design: geometric proportionalism and a set of illusion-strengthening rules in the proportionalism's "stochastic margin". Animal morphology, in its mechanistic-deductive revival, applies just one architectural principle, which is not always satisfactory. Whether a "Greek Classical" situation occurs in the architecture of living structure is to be investigated by extreme testing with deductive methods. Three deductive methods for explanation of living structure in animal morphology are proposed: the parts, the compromise, and the transformation deduction. The methods are based upon the systems concept for an organism, the flow chart for a functionalistic picture, and the network chart for a structuralistic picture, whereas the "optimal design" serves as the architectural principle for living structure. These methods show clearly the high explanatory power of deductive methods in morphology, but they also make one open end most explicit: neutral issues do exist. Full explanation of living structure asks for three entries: functional design within architectural and transformational constraints. The transformational constraint brings necessarily in a stochastic component: an at random variation being a sort of "free management space". This variation must be a variation from the deterministic principle of the optimal design, since any transformation requires space for plasticity in structure and action, and flexibility in role fulfilling. Nevertheless, finally the question comes up whether for animal structure a similar situation exists as in Greek Classical temples. This means that the at random variation, that is found when the optimal design is used to explain structure, comprises apart from a stochastic part also real deviations being yet another deterministic part. This deterministic part could be a set of rules that governs actualization in the "free management space".

A detailed look at the cytoskeletal architecture of the Giardia lamblia ventral disc.

PubMed

Brown, Joanna R; Schwartz, Cindi L; Heumann, John M; Dawson, Scott C; Hoenger, Andreas

2016-04-01

Giardia lamblia is a protistan parasite that infects and colonizes the small intestine of mammals. It is widespread and particularly endemic in the developing world. Here we present a detailed structural study by 3-D negative staining and cryo-electron tomography of a unique Giardia organelle, the ventral disc. The disc is composed of a regular array of microtubules and associated sheets, called microribbons that form a large spiral, held together by a myriad of mostly unknown associated proteins. In a previous study we analyzed by cryo-electron tomography the central microtubule portion (here called disc body) of the ventral disc and found a large portion of microtubule associated inner (MIPs) and outer proteins (MAPs) that render these microtubules hyper-stable. With this follow-up study we expanded our 3-D analysis to different parts of the disc such as the ventral and dorsal areas of the overlap zone, as well as the outer disc margin. There are intrinsic location-specific characteristics in the composition of microtubule-associated proteins between these regions, as well as large differences between the overall architecture of microtubules and microribbons. The lateral packing of microtubule-microribbon complexes varies substantially, and closer packing often comes with contracted lateral tethers that seem to hold the disc together. It appears that the marginal microtubule-microribbon complexes function as outer, laterally contractible lids that may help the cell to clamp onto the intestinal microvilli. Furthermore, we analyzed length, quantity, curvature and distribution between different zones of the disc, which we found to differ from previous publications. Copyright © 2016 Elsevier Inc. All rights reserved.

Development and flight evaluation of an augmented stability active controls concept with a small horizontal tail

NASA Technical Reports Server (NTRS)

Rising, J. J.; Kairys, A. A.; Maass, C. A.; Siegart, C. D.; Rakness, W. L.; Mijares, R. D.; King, R. W.; Peterson, R. S.; Hurley, S. R.; Wickson, D.

1982-01-01

A limited authority pitch active control system (PACS) was developed for a wide body jet transport (L-1011) with a flying horizontal stabilizer. Two dual channel digital computers and the associated software provide command signals to a dual channel series servo which controls the stabilizer power actuators. Input sensor signals to the computer are pitch rate, column-trim position, and dynamic pressure. Control laws are given for the PACS and the system architecture is defined. The piloted flight simulation and vehicle system simulation tests performed to verify control laws and system operation prior to installation on the aircraft are discussed. Modifications to the basic aircraft are described. Flying qualities of the aircraft with the PACS on and off were evaluated. Handling qualities for cruise and high speed flight conditions with the c.g. at 39% mac ( + 1% stability margin) and PACS operating were judged to be as good as the handling qualities with the c.g. at 25% (+15% stability margin) and PACS off.

Cryogenic system for the Origins Space Telescope: cooling a large space telescope to 4K with today's technology

NASA Astrophysics Data System (ADS)

DiPirro, M.; Fantano, L.; Canavan, E.; Leisawitz, D.; Carter, R.; Florez, A.; Amatucci, E.

2017-09-01

The Origins Space Telescope (OST) concept is one of four NASA Science Mission Directorate, Astrophysics Division, observatory concepts being studied for launch in the mid 2030's. OST's wavelength coverage will be from the midinfrared to the sub-millimeter, 6-600 microns. To enable observations at the zodiacal background limit the telescope must be cooled to about 4 K. Combined with the telescope size (currently the primary is 9 m in diameter) this appears to be a daunting task. However, simple calculations and thermal modeling have shown the cooling power required is met with several currently developed cryocoolers. Further, the telescope thermal architecture is greatly simplified, allowing simpler models, more thermal margin, and higher confidence in the final performance values than previous cold observatories. We will describe design principles to simplify modeling and verification. We will argue that the OST architecture and design principles lower its integration and test time and reduce its ultimate cost.

Conceptual Modeling in the Time of the Revolution: Part II

NASA Astrophysics Data System (ADS)

Mylopoulos, John

Conceptual Modeling was a marginal research topic at the very fringes of Computer Science in the 60s and 70s, when the discipline was dominated by topics focusing on programs, systems and hardware architectures. Over the years, however, the field has moved to centre stage and has come to claim a central role both in Computer Science research and practice in diverse areas, such as Software Engineering, Databases, Information Systems, the Semantic Web, Business Process Management, Service-Oriented Computing, Multi-Agent Systems, Knowledge Management, and more. The transformation was greatly aided by the adoption of standards in modeling languages (e.g., UML), and model-based methodologies (e.g., Model-Driven Architectures) by the Object Management Group (OMG) and other standards organizations. We briefly review the history of the field over the past 40 years, focusing on the evolution of key ideas. We then note some open challenges and report on-going research, covering topics such as the representation of variability in conceptual models, capturing model intentions, and models of laws.

Cryogenic System for the Origins Space Telescope: Cooling a Large Space Telescope to 4K with Today's Technology

NASA Technical Reports Server (NTRS)

DiPirro, M.; Fantano, L.; Canavan, E.; Leisawitz, D.; Carter, R.; Florez, A.; Amatucci, E.

2014-01-01

The Origins Space Telescope (OST) concept is one of four NASA Science Mission Directorate, Astrophysics Division, observatory concepts being studied for launch in the mid 2030's. OST's wavelength coverage will be from the midinfrared to the sub-millimeter, 6-600 microns. To enable observations at the zodiacal background limit the telescope must be cooled to about 4 K. Combined with the telescope size (currently the primary is 9 m in diameter) this appears to be a daunting task. However, simple calculations and thermal modeling have shown the cooling power required is met with several currently developed cryocoolers. Further, the telescope thermal architecture is greatly simplified, allowing simpler models, more thermal margin, and higher confidence in the final performance values than previous cold observatories. We will describe design principles to simplify modeling and verification. We will argue that the OST architecture and design principles lower its integration and test time and reduce its ultimate cost.

Evaluation of a Candidate Trace Contaminant Control Subsystem Architecture: The High Velocity, Low Aspect Ratio (HVLA) Adsorption Process

NASA Technical Reports Server (NTRS)

Kayatin, Matthew J.; Perry, Jay L.

2017-01-01

Traditional gas-phase trace contaminant control adsorption process flow is constrained as required to maintain high contaminant single-pass adsorption efficiency. Specifically, the bed superficial velocity is controlled to limit the adsorption mass-transfer zone length relative to the physical adsorption bed; this is aided by traditional high-aspect ratio bed design. Through operation in this manner, most contaminants, including those with relatively high potential energy are readily adsorbed. A consequence of this operational approach, however, is a limited available operational flow margin. By considering a paradigm shift in adsorption architecture design and operations, in which flows of high superficial velocity are treated by low-aspect ratio sorbent beds, the range of well-adsorbed contaminants becomes limited, but the process flow is increased such that contaminant leaks or emerging contaminants of interest may be effectively controlled. To this end, the high velocity, low aspect ratio (HVLA) adsorption process architecture was demonstrated against a trace contaminant load representative of the International Space Station atmosphere. Two HVLA concept packaging designs (linear flow and radial flow) were tested. The performance of each design was evaluated and compared against computer simulation. Utilizing the HVLA process, long and sustained control of heavy organic contaminants was demonstrated.

Architecture of Allosteric Materials and Edge Modes

NASA Astrophysics Data System (ADS)

Yan, Le; Ravasio, Riccardo; Brito, Carolina; Wyart, Matthieu

Allostery, a long-range elasticity-mediated interaction, remains the biggest mystery decades after its discovery in proteins. We introduce a numerical scheme to evolve functional materials that can accomplish a specified mechanical task. In this scheme, the number of solutions, their spatial architectures and the correlations among them can be computed. As an example, we consider an ``allosteric'' task, which requires the material to respond specifically to a stimulus at a distant active site. We find that functioning materials evolve a less-constrained trumpet-shaped region connecting the stimulus and active sites and that the amplitude of the elastic response varies non-monotonically along the trumpet. As previously shown for some proteins, we find that correlations appearing during evolution alone are sufficient to identify key aspects of this design. Finally, we show that the success of this architecture stems from the emergence of soft edge modes recently found to appear near the surface of marginally connected materials. Overall, our in silico evolution experiment offers a new window to study the relationship between structure, function, and correlations emerging during evolution. L.Y. was supported in part by the National Science Foundation under Grant No. NSF PHY11-25915. M.W. thanks the Swiss National Science Foundation for support under Grant No. 200021-165509 and the Simons Foundation Grant (#454953 Matthieu Wyart).

Jatropha curcas L. Root Structure and Growth in Diverse Soils

PubMed Central

Valdés-Rodríguez, Ofelia Andrea; Sánchez-Sánchez, Odilón; Pérez-Vázquez, Arturo; Caplan, Joshua S.; Danjon, Frédéric

2013-01-01

Unlike most biofuel species, Jatropha curcas has promise for use in marginal lands, but it may serve an additional role by stabilizing soils. We evaluated the growth and structural responsiveness of young J. curcas plants to diverse soil conditions. Soils included a sand, a sandy-loam, and a clay-loam from eastern Mexico. Growth and structural parameters were analyzed for shoots and roots, although the focus was the plasticity of the primary root system architecture (the taproot and four lateral roots). The sandy soil reduced the growth of both shoot and root systems significantly more than sandy-loam or clay-loam soils; there was particularly high plasticity in root and shoot thickness, as well as shoot length. However, the architecture of the primary root system did not vary with soil type; the departure of the primary root system from an index of perfect symmetry was 14 ± 5% (mean ± standard deviation). Although J. curcas developed more extensively in the sandy-loam and clay-loam soils than in sandy soil, it maintained a consistent root to shoot ratio and root system architecture across all types of soil. This strong genetic determination would make the species useful for soil stabilization purposes, even while being cultivated primarily for seed oil. PMID:23844412

Jatropha curcas L. root structure and growth in diverse soils.

PubMed

Valdés-Rodríguez, Ofelia Andrea; Sánchez-Sánchez, Odilón; Pérez-Vázquez, Arturo; Caplan, Joshua S; Danjon, Frédéric

2013-01-01

Unlike most biofuel species, Jatropha curcas has promise for use in marginal lands, but it may serve an additional role by stabilizing soils. We evaluated the growth and structural responsiveness of young J. curcas plants to diverse soil conditions. Soils included a sand, a sandy-loam, and a clay-loam from eastern Mexico. Growth and structural parameters were analyzed for shoots and roots, although the focus was the plasticity of the primary root system architecture (the taproot and four lateral roots). The sandy soil reduced the growth of both shoot and root systems significantly more than sandy-loam or clay-loam soils; there was particularly high plasticity in root and shoot thickness, as well as shoot length. However, the architecture of the primary root system did not vary with soil type; the departure of the primary root system from an index of perfect symmetry was 14 ± 5% (mean ± standard deviation). Although J. curcas developed more extensively in the sandy-loam and clay-loam soils than in sandy soil, it maintained a consistent root to shoot ratio and root system architecture across all types of soil. This strong genetic determination would make the species useful for soil stabilization purposes, even while being cultivated primarily for seed oil.

Identification and functional evaluation of cellular and viral factors involved in the alteration of nuclear architecture during herpes simplex virus 1 infection.

PubMed

Simpson-Holley, Martha; Colgrove, Robert C; Nalepa, Grzegorz; Harper, J Wade; Knipe, David M

2005-10-01

Herpes simplex virus 1 (HSV-1) replicates in the nucleus of host cells and radically alters nuclear architecture as part of its replication process. Replication compartments (RCs) form, and host chromatin is marginalized. Chromatin is later dispersed, and RCs spread past it to reach the nuclear edge. Using a lamin A-green fluorescent protein fusion, we provide direct evidence that the nuclear lamina is disrupted during HSV-1 infection and that the UL31 and UL34 proteins are required for this. We show nuclear expansion from 8 h to 24 h postinfection and place chromatin rearrangement and disruption of the lamina in the context of this global change in nuclear architecture. We show HSV-1-induced disruption of the localization of Cdc14B, a cellular protein and component of a putative nucleoskeleton. We also show that UL31 and UL34 are required for nuclear expansion. Studies with inhibitors of globular actin (G-actin) indicate that G-actin plays an essential role in nuclear expansion and chromatin dispersal but not in lamina alterations induced by HSV-1 infection. From analyses of HSV infections under various conditions, we conclude that nuclear expansion and chromatin dispersal are dispensable for optimal replication, while lamina rearrangement is associated with efficient replication.

Nature of the Lowstand Surface on the Gulf of Cádiz Shelf and the Guadiana Incised-Valley System: Preliminary Results from the LASEA 2013 Cruise

NASA Astrophysics Data System (ADS)

Lobo, F.; Lebreiro, S.; Antón, L.; Delivet, S.; Espinosa, S.; Fernández-Puga, M. C.; García, M.; Ibáñez, J.; Luján, M.; Mendes, I.; Reguera, M. I.; Sevillano, P.; Sinde, C.; Van Rooij, D.; Zarandona, P.

2014-12-01

The LASEA 2013 cruise was executed in August 2013 in the northern margin of the Gulf of Cádiz, with the main goal of collecting data from the Guadiana River-influenced shelf, in order to: (1) study changes affecting the entire drainage basin; (2) correlate shelf unit sequences with the upper slope sedimentary record, composed dominantly of contourite deposits in specific stretches of the margin. As a first approach, attention is paid to the most obvious sedimentary manifestation of the influence of the river on the shelf domain, represented by the Guadiana incised-valley system. The database comprises both geophysical and sedimentological records. Geophysical data include multibeam bathymetry, TOPAS profiles and single-channel Sparker seismic profiles. Sedimentological data include sediment cores collected with gravity- and vibro-corer devices. The lowstand erosional surface was mapped across the shelf. The lowstand surface exhibits two clearly contrasting patterns. In the outer shelf the surface isrepresented by an erosional truncation that can be planar or irregular. The lowstand surface is much more difficult to follow in the inner shelf, due to the amalgamation of erosional surfaces and the frequent stacking of coarse-grained deposits. Incised valleys are recognized at shallow waters (20-30 m) the most significant of them is at least 1.5 km wide in the most proximal (recognized) section, decreasing seawards in width. The internal architecture of the valley exhibits the intercalation of laterally prograding sediment bodies and high-amplitude, subparallel configurations laterally related to valley margin prograding wedges. The internal facies architecture suggests a transition from relatively high-energy fluvial to proximal estuarine environment to a lower-energy estuarine depositional environment. Thus, the study of the valley extension into the shelf is expected to provide clues for the recent reorganization of the entire fluvial system, during the course of the postglacial sea-level rise and ensuing sea-level stabilization. Acknowledgements: this study was completed in the framework of the project CGL2011-30302-C02-02. It is also a contribution to the INQUA International Focus Group on Rapid environmental changes and human activity impacting continental shelf systems.

New Crustal Boundary Revealed Beneath the Ross Ice Shelf, Antarctica, through ROSETTA-Ice Integrated Aerogeophysics, Geology, and Ocean Research

NASA Astrophysics Data System (ADS)

Tinto, K. J.; Siddoway, C. S.; Bell, R. E.; Lockett, A.; Wilner, J.

2017-12-01

Now submerged within marine plateaus and rises bordering Antarctica, Australia and Zealandia, the East Gondwana accretionary margin was a belt of terranes and stitched by magmatic arcs, later stretched into continental ribbons separated by narrow elongate rifts. This crustal architecture is known from marine geophysical exploration and ocean drilling of the mid-latitude coastal plateaus and rises. A concealed sector of the former East Gondwana margin that underlies the Ross Ice Shelf (RIS), Antarctica, is the focus of ROSETTA-ICE, a new airborne data acquisition campaign that explores the crustal makeup, tectonic boundaries and seafloor bathymetry beneath RIS. Gravimeters and a magnetometer are deployed by LC130 aircraft surveying along E-W lines spaced at 10 km, and N-S tie lines at 55 km, connect 1970s points (RIGGS) for controls on ocean depth and gravity. The ROSETTA-ICE survey, 2/3 completed thus far, provides magnetic anomalies, Werner depth-to-basement solutions, a new gravity-based bathymetric model at 20-km resolution, and a new crustal density map tied to the 1970s data. Surprisingly, the data reveal that the major lithospheric boundary separating East and West Antarctica lies 300 km east of the Transantarctic Mountains, beneath the floating RIS. The East and West regions have contrasting geophysical characteristics and bathymetry, with relatively dense lithosphere, low amplitude magnetic anomalies, and deep bathymetry on the East Antarctica side, and high amplitude magnetic anomalies, lower overall density and shallower water depths on the West Antarctic side. The Central High, a basement structure cored at DSDP Site 270 and seismically imaged in the Ross Sea, continues beneath RIS as a faulted but coherent crustal ribbon coincident with the tectonic boundary. The continuity of Gondwana margin crustal architecture discovered beneath the West Antarctic Ice Sheet requires a revision of the existing tectonic framework. The sub-RIS narrow rift basins and transfer zones, and the crustal boundary that is well-separated from the Transantarctic Mountains front, control the bathymetry, impart the large-scale patterning within and upon the base of the ice sheet, influence oceanographic circulation, and therefore are of import for Ross Ice Shelf stability.

Architecture of buried reverse fault zone in the sedimentary basin: A case study from the Hong-Che Fault Zone of the Junggar Basin

NASA Astrophysics Data System (ADS)

Liu, Yin; Wu, Kongyou; Wang, Xi; Liu, Bo; Guo, Jianxun; Du, Yannan

2017-12-01

It is widely accepted that the faults can act as the conduits or the barrier for oil and gas migration. Years of studies suggested that the internal architecture of a fault zone is complicated and composed of distinct components with different physical features, which can highly influence the migration of oil and gas along the fault. The field observation is the most useful methods of observing the fault zone architecture, however, in the petroleum exploration, what should be concerned is the buried faults in the sedimentary basin. Meanwhile, most of the studies put more attention on the strike-slip or normal faults, but the architecture of the reverse faults attracts less attention. In order to solve these questions, the Hong-Che Fault Zone in the northwest margin of the Junggar Basin, Xinjiang Province, is chosen for an example. Combining with the seismic data, well logs and drill core data, we put forward a comprehensive method to recognize the internal architectures of buried faults. High-precision seismic data reflect that the fault zone shows up as a disturbed seismic reflection belt. Four types of well logs, which are sensitive to the fractures, and a comprehensive discriminated parameter, named fault zone index are used in identifying the fault zone architecture. Drill core provides a direct way to identify different components of the fault zone, the fault core is composed of breccia, gouge, and serpentinized or foliated fault rocks and the damage zone develops multiphase of fractures, which are usually cemented. Based on the recognition results, we found that there is an obvious positive relationship between the width of the fault zone and the displacement, and the power-law relationship also exists between the width of the fault core and damage zone. The width of the damage zone in the hanging wall is not apparently larger than that in the footwall in the reverse fault, showing different characteristics with the normal fault. This study provides a comprehensive method in identifying the architecture of buried faults in the sedimentary basin and would be helpful in evaluating the fault sealing behavior.

Mapping rift domains within an inverted hyperextended rift system: The role of rift inheritance in controlling the present-day structure of the North Iberian margin (Bay of Biscay)

NASA Astrophysics Data System (ADS)

Cadenas, Patricia; Fernández-Viejo, Gabriela; Álvarez-Pulgar, Javier; Tugend, Julie; Manatschal, Gianreto; Minshull, Tim

2017-04-01

This study presents a new rift domain map in the central and western North Iberian margin, in the southern Bay of Biscay. This margin was structured during polyphase Triassic to Lower Cretaceous rifting events which led to hyperextension and exhumation and the formation of oceanic crust during a short-lived seafloor spreading period. Extension was halted due to the Alpine convergence between the Iberian and the European plates which led to the formation of the Cantabrian-Pyrenean orogen during the Cenozoic. In the Bay of Biscay, while the northern Biscay margin was slightly inverted, the North Iberian margin, which is at present-day part of the western branch of the Alpine belt together with the Cantabrian Mountains, exhibits several degrees of compressional reactivation. This makes this area a natural laboratory to study the influence of rift inheritance into the inversion of a passive margin. Relying on the interpretation of geological and geophysical data and the integration of wide-angle results, we have mapped five rift domains, corresponding to the proximal, necking, hyperthinned, exhumed mantle, and oceanic domains. One of the main outcomes of this work is the identification of the Asturian Basin as part of a hyperthinned domain bounded to the north by the Le Danois basement high. We interpret Le Danois High as a rift-related crustal block inherited from the margin structure. Our results suggest that the inherited rift architecture controlled the subsequent compressional reactivation. The hyperextended domains within the abyssal plain focused most of the compression resulting in the development of an accretionary wedge and the underthrusting of part of these distal domains beneath the margin. The presence of the Le Danois continental block added complexity, conditioning the inversion undergone by the Asturian Basin. This residual block of less thinned continental crust acted as a local buttress hampering further compressional reactivation within the platform and the inner basin, which were only slightly inverted and uplifted passively due to the underthrusting of the hyperextended domains beneath Le Danois High. The new inverted rift domain map adds some constraints to support kinematic reconstructions and confine palinspatic restorations of the inverted rifted margin. Furthermore, it provides more insights to comprehend the strain partitioning within the Bay of Biscay-Pyrenean inverted hyperextended rift and the broad structural variability observed in such a reduced area, arising from the strong segmentation and the obliquity between the NW-SE and WNW-ESE trending rift structures and the E-W compressional front.

Mammographic and Ultrasonographic Findings of Oxidized Regenerated Cellulose in Breast Cancer Surgery: A 5-Year Experience.

PubMed

Giuliani, Michela; Fubelli, Rita; Patrolecco, Federica; Rella, Rossella; Borelli, Cristina; Buccheri, Chiara; Di Giovanni, Silvia Eleonora; Belli, Paolo; Romani, Maurizio; Rinaldi, Pierluigi; Bufi, Enida; Franceschini, Gianluca; Bonomo, Lorenzo

2015-10-01

The purpose of this study was to describe the ultrasonographic (US) and mammographic (MX) findings in patients who underwent breast-conserving surgery followed by oxidized regenerated cellulose (ORC) implantation in the surgical cavity and their size variations in follow-up. We retrospectively reviewed 417 MX and 743 US images performed between January 2009 and January 2014 for 262 women who underwent breast-conserving surgery. All patients underwent US, only 203 women underwent MX examination. In 170 of 262 patients, US examinations showed abnormal findings. Three main US patterns were identified: (1) complex masses: well-encapsulated ipoisoechoic lesions with circumscribed margins with internal hyperechoic nodules (56%); (2) hypoanechoic lesions without internal hyperechoic nodules (24%); and (3) completely anechoic collections (20%). Moreover, Doppler ultrasound examination was performed on all of the patients. In 95 of 203 patients, MX examinations showed abnormalities. Four main MX patterns were identified: (1) round or oval opacity with circumscribed margins (58%); (2) round or oval opacity with indistinct or ill-defined margins (17%); (3) irregular opacity with indistinct or spiculated margins (9%); and (4) architectural distortion or focal asymmetry (15%). Most of the lesions showed a decrease in size at US and MX follow-up examination and the decrease was statistically significant (P < .01). When applied to the surgical residual cavity, ORC aids to control local hemorrhage and reduce the risk of postoperative infections, but can lead to alterations in surgical scar. Thus, knowledge of the radiological findings might allow avoidance of misdiagnosis of tumor recurrence or unnecessary diagnostic examinations. Copyright © 2015 Elsevier Inc. All rights reserved.

30/20 GHz communications systems baseband processor development

NASA Astrophysics Data System (ADS)

Brown, L.; Sabourin, D.; Stilwell, J.; McCallister, R.; Borota, M.

The architecture and system design concepts for a commercial satellite communications system planned for the 1990's has been developed. The system provides data communications between the individual users via trunking and customer premise service terminals utilizing a central switching satellite operating in a time-division multiple-access mode. Baseband processing is employed to route and control traffic on an individual message basis while providing significant advantages in improved link margins and system flexibility. Key technology developments required to prove the flight readiness of the baseband processor design are being verified in the baseband processor proof-of-concept model described herein.

30/20 GHz communications systems baseband processor development

NASA Technical Reports Server (NTRS)

Brown, L.; Sabourin, D.; Stilwell, J.; Mccallister, R.; Borota, M.

1982-01-01

The architecture and system design concepts for a commercial satellite communications system planned for the 1990's has been developed. The system provides data communications between the individual users via trunking and customer premise service terminals utilizing a central switching satellite operating in a time-division multiple-access mode. Baseband processing is employed to route and control traffic on an individual message basis while providing significant advantages in improved link margins and system flexibility. Key technology developments required to prove the flight readiness of the baseband processor design are being verified in the baseband processor proof-of-concept model described herein.

Role of Silica Redistribution in the Rate-State Behavior of Megathrusts: Field Observations and Experimental Results

NASA Astrophysics Data System (ADS)

Fisher, D. M.; Den Hartog, S. A. M.

2014-12-01

Observations of ancient fault zones and results of high temperature friction experiments indicate that silica redistribution influences the rate (response to velocity increases) and state (time-dependent healing) behavior of megathrusts. The Kodiak Accretionary Complex in Alaska has four shear zones that record plate boundary deformation: the Ghost Rocks mélange, the Uganik thrust, the Uyak mélange, and the central belt of the Kodiak Formation. All these examples of underplated rocks represent top-toward-the-trench shear zones that extend along the plate margin for 100's of kms. The first three examples were accreted within the seismogenic zone and record a progressive history from stratal disruption and particulate flow to localized shearing on pervasive web-like arrays of scaly microfaults in shales. Microfaults show evidence for silica dissolution and local reprecipitation in dilational stepovers and in intensely veined sandstone blocks. The fourth example (the central belt) was accreted further downdip, and these rocks have pervasive, regularly spaced en echelon quartz vein systems. Microstructures within veins indicate periodic cracking and sealing during progressive simple shear. Silica depletion zones adjacent to veins indicate diffusive transport of silica in response to local chemical potential gradients. A simple 1-D transport-kinetics model indicates that cracks in this case could be filled with quartz in less than a year and in as little as a week. Rock friction experiments on lithologies similar to Kodiak examples depict three distinct regimes of frictional behavior as a function of increasing temperature, with velocity weakening in a T range that can be related to the seismogenic zone. These three regimes are predicted by a model for gouge deformation that includes thermally activated pressure solution during shear of quartz grains embedded in a foliated matrix. The slip instabilities that characterize the seismogenic zone may therefore be related in part to grain scale diffusive mass transfer of silica. The observations of Kodiak Fault zones indicate that silica redistribution also plays an important role in the interseismic period through crack healing and dissolution of silica, both along the plate interface and within the adjacent rocks that store elastic strain.

Stratigraphic architecture and gamma ray logs of deeper ramp carbonates (Upper Jurassic, SW Germany)

NASA Astrophysics Data System (ADS)

Pawellek, T.; Aigner, T.

2003-07-01

The objective of this paper is to contribute to the development of sequence stratigraphic models for extensive epicontinental carbonate systems deposited over cratonic areas. Epicontinental carbonates of the SW German Upper Jurassic were analysed in terms of microfacies, sedimentology and sequence stratigraphy based on 2.5 km of core, 70 borehole gamma ray logs and 24 quarries. Facies analysis revealed six major facies belts across the deeper parts of the carbonate ramp, situated generally below fair-weather wave base, and mostly below average storm wave base but in the reach of occasional storm events. Observed stratigraphic patterns differ in some aspects from widely published sequence stratigraphic models: Elementary sedimentary cycles are mostly more or less symmetrical and are, thus, referred to as "genetic sequences" or "genetic units" [AAAPG Bull. 55 (1971) 1137; Frazier, D.E., 1974. Depositional episodes: their relationship to the Quaternary stratigraphic framework in the northwestern portion of the Gulf Basin. University of Texas, Austin, Bureau of Economic Geology Geologicalo Circular 71-1; AAPG Bull. 73 (1989) 125; Galloway, W.E., Hobday, D.K., 1996. Terrigenous Clastic Depositional Systems. 489 pp., Springer; Cross, T.A., Baker, M.R., Chapin, M.S., Clark, M.S., Gardner, M.H., Hanson, M.S., Lessenger, M.A., Little, L.D., McDonough, K.J., Sonnenfeld, M.D., Valasek, D.W., Williams, M.R., Witter, D.N., 1993. Applications of high-resolution sequence stratigraphy to reservoir analysis. Edition Technip 1993, 11-33; Bull. Cent. Rech. Explor. Prod. Elf-Aquitaine 16 (1992) 357; Homewood, P., Mauriaud, P., Lafont, F., 2000. Best practices in sequence stratigraphy. Elf EP Mem. 25, 81 pp.; Homewood, P., Eberli, G.P., 2000. Genetic stratigraphy on the exploration and production scales. Elf EP Mem. 24, 290 pp.], in contrast to the asymmetrical, shallowing-upward "parasequences" of the EXXON approach. Neither sequence boundaries nor maximum flooding surfaces could be clearly delineated. Cycle boundaries are generally not represented by sharp stratal surfaces but are always transitional and, thus, referred to as "turnarounds" [Nor. Pet. Soc. Spec. Publ. 8 (1998) 171]. Several types of genetic sequences were delineated. Both major types of facies and sequences show characteristic gamma ray log signatures. Based on the cycle stacking and the gamma ray patterns, a hierarchy of sequences was recognized, probably driven in part by 100,000- and 400,000-year Milankovitch signals. The cyclicity allowed regional correlations across various depositional environments such as sponge-microbial bioherms and coeval basins. The basin-wide correlation revealed evidence for a subtle clinoform-type stratigraphic architecture along very gentle slopes, rather than a so far assumed simple "layer cake" pattern.

What Do Kinematic Models Imply About the Constitutive Properties of Rocks Deformed in Flat-Ramp-Flat Folds?

NASA Astrophysics Data System (ADS)

Cruz, L.; Nevitt, J. M.; Seixas, G.; Hilley, G. E.

2017-10-01

Kinematic theories of flat-ramp-flat folds relate fault angles to stratal dips in a way that allows prediction of structural geometries in areas of economic or scientific interest. However, these geometric descriptions imply constitutive properties of rocks that might be discordant with field and laboratory measurements. In this study, we compare deformation resulting from kinematic and mechanical models of flat-ramp-flat folds with identical geometries to determine the conditions over which kinematic models may be reasonably applied to folded rocks. Results show that most mechanical models do not conform to the geometries predicted by the kinematic models, and only low basal friction (μ ≤ 0.1) and shallow ramps (ramp angle ≤10°) produce geometries consistent with kinematic predictions. This implies that the kinematic models might be appropriate for a narrow set of geometric and basal fault friction parameters.

New technologies of mining stratal minerals and their computation

NASA Astrophysics Data System (ADS)

Beysembayev, K. M.; Reshetnikova, O. S.; Nokina, Z. N.; Teliman, I. V.; Asmagambet, D. K.

2018-03-01

The paper considers the systems of flat and volumetric modeling of controlling long-wall faces for schemes with rock collapse of the immediate and main roof and smooth lowering of the remaining layers, as well as in forming a vault over the face. Stress distributions are obtained for the reference pressure zone. They are needed for recognizing the active state of the long-wall face in the feedback mode. The project of the system “support - lateral rocks” is represented by a multidimensional network base. Its connections reflect the elements of the system or rocks, workings, supports with nodes and parts. The connections reflect the logic of the operation of machines, assemblies and parts, and the types of their mechanical connections. At the nodes of the base, there are built-in systems of object-oriented programming languages. This allows combining spatial elements of the system into a simple neural network.

Sequence stratigraphic and sedimentologic significance of biogenic structures from a late Paleozoic marginal- to open-marine reservoir, Morrow Sandstone, subsurface of southwest Kansas, USA

USGS Publications Warehouse

Buatois, L.A.; Mangano, M.G.; Alissa, A.; Carr, T.R.

2002-01-01

Integrated ichnologic, sedimentologic, and stratigraphic studies of cores and well logs from Lower Pennsylvanian oil and gas reservoirs (lower Morrow Sandstone, southwest Kansas) allow distinction between fluvio-estuarine and open marine deposits in the Gentzler and Arroyo fields. The fluvio-estuarine facies assemblage is composed of both interfluve and valley-fill deposits, encompassing a variety of depositional environments such as fluvial channel, interfluve paleosol, bay head delta, estuary bay, restricted tidal flat, intertidal channel, and estuary mouth. Deposition in a brackish-water estuarine valley is supported by the presence of a low diversity, opportunistic, impoverished marine ichnofaunal assemblage dominated by infaunal structures, representing an example of a mixed, depauperate Cruziana and Skolithos ichnofacies. Overall distribution of ichnofossils along the estuarine valley was mainly controlled by the salinity gradient, with other parameters, such as oxygenation, substrate and energy, acting at a more local scale. The lower Morrow estuarine system displays the classical tripartite division of wave-dominated estuaries (i.e. seaward-marine sand plug, fine-grained central bay, and sandy landward zone), but tidal action is also recorded. The estuarine valley displays a northwest-southeast trend, draining to the open sea in the southeast. Recognition of valley-fill sandstones in the lower Morrow has implications for reservoir characterization. While the open marine model predicts a "layer-cake" style of facies distribution as a consequence of strandline shoreline progradation, identification of valley-fill sequences points to more compartmentalized reservoirs, due to the heterogeneity created by valley incision and subsequent infill. The open-marine facies assemblage comprises upper, middle, and lower shoreface; offshore transition; offshore; and shelf deposits. In contrast to the estuarine assemblage, open marine ichnofaunas are characterized by a high diversity of biogenic structures representing the activity of a benthic fauna developed under normal salinity conditions. Trace fossil and facies analyses allow environmental subdivision of the shoreface-offshore successions and suggest deposition in a weakly storm-affected nearshore area. An onshore-offshore replacement of the Skolithos ichnofacies by the Cruziana ichnofacies is clearly displayed. The lower Morrow fluvio-estuarine valley was incised during a drop of sea level coincident with the Mississippian-Pennsylvanian transition, but was mostly filled during a subsequent transgression. The transgressive nature of the estuarine infill is further indicated by the upward replacement of depauperate brackish-water trace fossil assemblages by the open-marine Cruziana ichnofacies. Additional stratal surfaces of allostratigraphic significance identified within the estuary include the bayline surface, the tidal ravinement surface, the wave ravinement surface, and a basinwide flooding surface recording inundation of the valley interfluves. A younger sequence boundary within the lower Morrow is also recorded in the Gentzler field at the base of a forced regression shoreface, demarcated by the firmground Glossifungites ichnofacies, indicating a rapid basinward facies migration during a sea-level drop. Trace fossil models derived from the analysis of Mesozoic and Cenozoic reservoirs are generally applicable to the study of these late Paleozoic reservoirs. Pennsylvanian brackish-water facies differ ichnologically from their post-Paleozoic counterparts, however, in that they have: (1) lower trace fossil diversity, (2) lower degree of bioturbation, (3) scarcity of crustacean burrows, (4) absence of firmground suites, and (5) absence of ichnotaxa displaying specific architectures designed to protect the tracemaker from salinity fluctuations. Morrow open-marine ichnofaunas closely resemble their post-Paleozoic equivalents. ?? 2002 Elsevier Science B.V. All rights reserved.

Structural style and tectonic evolution of the easternmost Gulf of Aden conjugate margins (Socotra - Southern Oman)

NASA Astrophysics Data System (ADS)

Nonn, Chloe; Leroy, Sylvie; Castilla, Raymi; de Clarens, Philippe; Lescanne, Marc

2016-04-01

Observations from distal rifted margins in present day magma-poor rifted margins led to the discovery of hyperextended crust and exhumed sub-continental mantle. This finding allowed to better figure out how thinning process are accommodate by tectonic structures, forming various crustal domains, as the deformation localized towards the future area of breakup. However, some of the current challenges are about clarifying how factors as oblique kinematic, pre-existing structures and volcanism can control the 3D geometry and crustal architecture of the passive margins? A key to better understand the rifting evolution in its entirety is to study conjugate margins. The gulf of Aden is a young oceanic basin (with a global trend about N75°E) oblique to the divergence (about 30°N), separating Arabia from Somalia of less than 800 km. Thanks to its immerged margins and its thin post-rift sediment cover, the gulf of Aden basin is a natural laboratory to investigate conjugate margins and strain localisation throughout the rift history. In this contribution, we focus our interest on offshore Socotra Island (Yemen) and its conjugate in Southeastern Oman. This area extends from Socotra-Hadbeen (SHFZ) and the eastern Gulf of Aden fault zones (EGAFZ). In the easternmost part of the gulf of Aden, we provide new insights into crustal deformation and emplacement of the new oceanic crust thanks to bathymetric, magnetic, gravimetric data and single-, multi-channel, high speed seismic reflection data collected during Encens-Sheba (2000), Encens (2006) and the more recent Marges-Aden (2012) cruises respectively. The results obtained after compilation of these data, previous geological (field works) and geophysical (receiver functions, Pn-tomography, magnetic anomalies, heat flow) studies on the focused area, allowed us to provide new structural mapping and stratigraphic correlation between onshore and offshore parts of Socotra and Oman margins. We precisely defined and map crustal domains, syn-tectonic structures and oblique accommodation zones to highlighted asymmetrical margins, characterized by strong lateral variability of crustal domains along and across strike. From external to internal domains of the margins and in between SHFZ and EGAFZ (first-order segment), this study details sharp necking domain and complex transition from hyperextended to oceanic crust characterized by: (i) hyperextended crust affected by volcanic extrusions; (ii) detachment faulting in the distal part of the margins allowing exhumation; (iii) volcanic constructions in the exhumation domain; (iv) a complex proto-oceanic crust. We highlight a significant second-order segmentation characterized by six N20°E trending transfer zones, limiting seven 25 - 60 km length segments and affecting necking domain as well as the ocean-continent transition. Based on interpretative cross-sections and detailed stratigraphic analysis, we discuss the complex temporal and spatial evolution of conjugate margins: (i) the margins segmentation and the relationship with structural inheritance (ii) the set-up of a long-offset detachment fault and the nature of the exhumed basement (iv) the origin and timing of magmatic events and the onset of proto-oceanic crust.

Architecture of the human renal inner medulla and functional implications

PubMed Central

Wei, Guojun; Rosen, Seymour; Dantzler, William H.

2015-01-01

The architecture of the inner stripe of the outer medulla of the human kidney has long been known to exhibit distinctive configurations; however, inner medullary architecture remains poorly defined. Using immunohistochemistry with segment-specific antibodies for membrane fluid and solute transporters and other proteins, we identified a number of distinctive functional features of human inner medulla. In the outer inner medulla, aquaporin-1 (AQP1)-positive long-loop descending thin limbs (DTLs) lie alongside descending and ascending vasa recta (DVR, AVR) within vascular bundles. These vascular bundles are continuations of outer medullary vascular bundles. Bundles containing DTLs and vasa recta lie at the margins of coalescing collecting duct (CD) clusters, thereby forming two regions, the vascular bundle region and the CD cluster region. Although AQP1 and urea transporter UT-B are abundantly expressed in long-loop DTLs and DVR, respectively, their expression declines with depth below the outer medulla. Transcellular water and urea fluxes likely decline in these segments at progressively deeper levels. Smooth muscle myosin heavy chain protein is also expressed in DVR of the inner stripe and the upper inner medulla, but is sparsely expressed at deeper inner medullary levels. In rodent inner medulla, fenestrated capillaries abut CDs along their entire length, paralleling ascending thin limbs (ATLs), forming distinct compartments (interstitial nodal spaces; INSs); however, in humans this architecture rarely occurs. Thus INSs are relatively infrequent in the human inner medulla, unlike in the rodent where they are abundant. UT-B is expressed within the papillary epithelium of the lower inner medulla, indicating a transcellular pathway for urea across this epithelium. PMID:26290371

The giant Carlin gold province: A protracted interplay of orogenic, basinal, and hydrothermal processes above a lithospheric boundary

USGS Publications Warehouse

Emsbo, P.; Groves, D.I.; Hofstra, A.H.; Bierlein, F.P.

2006-01-01

Northern Nevada hosts the only province that contains multiple world-class Carlin-type gold deposits. The first-order control on the uniqueness of this province is its anomalous far back-arc tectonic setting over the rifted North American paleocontinental margin that separates Precambrian from Phanerozoic subcontinental lithospheric mantle. Globally, most other significant gold provinces form in volcanic arcs and accreted terranes proximal to convergent margins. In northern Nevada, periodic reactivation of basement faults along this margin focused and amplified subsequent geological events. Early basement faults localized Devonian synsedimentary extension and normal faulting. These controlled the geometry of the Devonian sedimentary basin architecture and focused the discharge of basinal brines that deposited syngenetic gold along the basin margins. Inversion of these basins and faults during subsequent contraction produced the complex elongate structural culminations that characterize the anomalous mineral deposit "trends." Subsequently, these features localized repeated episodes of shallow magmatic and hydrothermal activity that also deposited some gold. During a pulse of Eocene extension, these faults focused advection of Carlin-type fluids, which had the opportunity to leach gold from gold-enriched sequences and deposit it in reactive miogeoclinal host rocks below the hydrologic seal at the Roberts Mountain thrust contact. Hence, the vast endowment of the Carlin province resulted from the conjunction of spatially superposed events localized by long-lived basement structures in a highly anomalous tectonic setting, rather than by the sole operation of special magmatic or fluid-related processes. An important indicator of the longevity of this basement control is the superposition of different gold deposit types (e.g., Sedex, porphyry, Carlin-type, epithermal, and hot spring deposits) that formed repeatedly between the Devonian and Miocene time along the trends. Interestingly, the large Cretaceous Alaska-Yukon intrusion-related gold deposits (e.g., Fort Knox) are associated with the northern extension of the same lithospheric margin in the Selwyn basin, which experienced an analogous series of geologic events. ?? Springer-Verlag 2006.

Quantification of the effects of eustasy, subsidence, and sediment supply on Miocene sequences, mid-Atlantic margin of the United States

USGS Publications Warehouse

Browning, J.V.; Miller, K.G.; McLaughlin, P.P.; Kominz, M.A.; Sugarman, P.J.; Monteverde, D.; Feigenson, M.D.; Hernandez, J.C.

2006-01-01

We use backstripping to quantify the roles of variations in global sea level (eustasy), subsidence, and sediment supply on the development of the Miocene stratigraphic record of the mid-Atlantic continental margin of the United States (New Jersey, Delaware, and Maryland). Eustasy is a primary influence on sequence patterns, determining the global template of sequences (i.e., times when sequences can be preserved) and explaining similarities in Miocene sequence architecture on margins throughout the world. Sequences can be correlated throughout the mid-Atlantic region with Sr-isotopic chronology (??0.6 m.y. to ??1.2 m.y.). Eight Miocene sequences correlate regionally and can be correlated to global ??18O increases, indicating glacioeustatic control. This margin is dominated by passive subsidence with little evidence for active tectonic overprints, except possibly in Maryland during the early Miocene. However, early Miocene sequences in New Jersey and Delaware display a patchwork distribution that is attributable to minor (tens of meters) intervals of excess subsidence. Backstripping quantifies that excess subsidence began in Delaware at ca. 21 Ma and continued until 12 Ma, with maximum rates from ca. 21-16 Ma. We attribute this enhanced subsidence to local flexural response to the progradation of thick sequences offshore and adjacent to this area. Removing this excess subsidence in Delaware yields a record that is remarkably similar to New Jersey eustatic estimates. We conclude that sea-level rise and fall is a first-order control on accommodation providing similar timing on all margins to the sequence record. Tectonic changes due to movement of the crust can overprint the record, resulting in large gaps in the stratigraphic record. Smaller differences in sequences can be attributed to local flexural loading effects, particularly in regions experiencing large-scale progradation. ?? 2006 Geological Society of America.

Preliminary results from combined wide-angle and reflection seismic data in the Natal Valley, South Mozambique margin across the Almirante Leite volcanic ridge : MZ2 profile (MOZ3/5 cruise).

NASA Astrophysics Data System (ADS)

Verrier, Fanny; Leprêtre, Angélique; Evain, Mikael; Schnurle, Philippe; Watremez, Louise; Aslanian, Daniel; De Clarens, Philippe; Afonso Dias, Nuno; Afilhado, Alexandra; Leroy, Sylvie; d'Acremont, Elia; Castilla, Raymi; Moulin, Maryline

2017-04-01

The study of South Mozambique passive margin is essential to understand its rifting evolution and better constrain kinematic reconstructions model of the Indian Ocean. MOZ3-5 oceanographic cruises (2016) is part of the PAMELA project (PAssive Margin Exploration LAboratory), conducted by TOTAL, IFREMER, in collaboration with Université de Bretagne Occidentale, Université Rennes 1, Université Pierre and Marie Curie, CNRS et IFPEN. These campaigns allowed the acquisition of wide-angle and multichannel seismic data as well as high resolution bathymetric data, dredges, magnetic and gravimetric data. This work focuses on the deep structure of the northern segment of the Natal Valley which was investigated along a 300 km long E-W seismic transect cross-cutting the Almirante Leite volcanic ridge (MZ2 profile). The wide-angle data set is composed of 23 OBS (Ocean Bottom Seismometers) and 19 LSS (Land Seismic Station) spaced by about 12 km and 4-5 km respectively. Forward modelling of the wide-angle data led to a preliminary 2D P-waves velocity model revealing the sedimentary architecture, crustal and lithospherical structures and shallow high velocity material at the volcanic ridge. The aim of this work is to present the first results on the crustal structure from P-waves velocity modeling along the profile MZ2, in order to discuss the sedimentary sequences, the geometry and nature of the crust (oceanic or continental) as well as structures associated with volcanism, and to better understand the margin's evolution. The post-doc of Fanny Verrier is co-funded by TOTAL and IFREMER as part of the PAMELA (Passive Margin Exploration Laboratories) scientific project. Moulin, M., Aslanian, D., 2016. PAMELA-MOZ03 cruise, RV Pourquoi pas ?, http://dx.doi.org/10.17600/16001600 Moulin, M., Evain, M., 2016. PAMELA-MOZ05 cruise, RV Pourquoi pas ?, http://dx.doi.org/10.17600/16009500

Tectonic evolution of the Paranoá basin: New evidence from gravimetric and stratigraphic data

NASA Astrophysics Data System (ADS)

Martins-Ferreira, Marco Antonio Caçador; Campos, José Eloi Guimarães; Von Huelsen, Monica Giannoccaro

2018-06-01

Field gravimetric and stratigraphic surveys were conducted with the aim to constraint the mechanisms responsible for the initiation of the Stenian-Tonian Paranoá basin, central Brazil, a subject not yet studied in detail. The Paranoá Group crops out in the external zone of the Brasília Belt, a Neoproterozoic orogen in the western margin of the São Francisco Craton. Detailed geological mapping confirmed the existence of a regional scale fault that controlled sedimentation of the Paranoá Group during the deposition of its basal formations, revealing important details about basin initiation and early evolution. Gravimetric modeling indicates the existence of paleorift structures beneath the Paranoá sequence in the study area. Results from both stratigraphic and gravimetric surveys show strong evidence of mechanical subsidence by faulting during basin initiation. Unsorted, angular, clasts cut by quartz veins and brecciated boulders present in the basal conglomerate, support this hypothesis. Basin initiation faults coincide with deeper paleorift faults and are thus interpreted as reactivations of the older Statherian Araí Rift. The reactivations favored an initial regime of mechanical subsidence, dominated by the development of epirogenic arches subsiding at different rates. Apart from faulting activity, the post-basal sequence presents no evidence of rift environment in the strict sense. Besides, the great lateral continuity and relatively constant thickness of facies, indicate that an initial mechanic subsidence rapidly gave way to flexural subsidence during subsequent stages of basin evolution. The Paranoá Group do not present reliable characteristics that would allow its strict classification as a passive margin. Its main stratigraphic characteristics, tectonic location and basement architecture, indicate that the Paranoá Group was deposited in a cratonic margin basin, and may have been either connected to a passive margin basin at times of sea level rise, or evolved to a passive margin later in time.

Sequence stratigraphy, tectonics and hydrocarbon trap geometries of Middle Tertiary strata in the southern San Joaquin Basin, California

DOE Office of Scientific and Technical Information (OSTI.GOV)

Phillips, S.; Hewlett, J.S.; Bazeley, W.J.M.

1996-01-01

Tectonic evolution of the southern San Joaquin basin exerted a fundamental control on Cenozoic sequence boundary development, reservoir, source and seal facies distribution, and hydrocarbon trap development. Spatial and temporal variations in Tertiary sequence architecture across the basin reflect differences in eastside versus westside basin-margin geometries and deformation histories. Deposition of Tertiary sequences initiated in a forearc basin setting, bounded on the east by a ramp-margin adjacent to the eroded Sierran arc complex and on the west by the imbricated accretionary wedge of the Coast Ranges thrust. The major stages of Cenozoic basin evolution are: (1) Episodic compressional folding andmore » thrusting associated with oblique convergence of the Farallon and North American plates (Late Cretaceous to Oligocene), (2) localized folding and onset of basin subsidence related to Pacific Plate reorganization, microplate formation and rotation (Oligocene to Early Miocene), (3) transtensional faulting, folding basin subsidence associated with initiation of the San Andreas transform and continued microplate rotation (Micocene to Pliocene), and (4) compressional folding, extensional and strike- slip faulting related to evolution of the Pacific-North American transform boundary (Plio- Pleistocene). Complex stratigraphic relationships within Eocene to Middle Miocene rocks provide examples of tectonic influences on sequence architecture. These include development of: (1) Tectonically enhanced sequence boundaries (Early Eocene base Domengine unconformity) and local mid-sequence angular unconformities, (2) westside-derived syntectonic [open quotes]lowstand[close quotes] systems (Yokut/Turitella Silt wedge and Leda Sand/Cymric/Salt Creek wedge), (3) regional seals associated with subsidence-related transgressions (Round Mountain Silt), and (4) combination traps formed by structural inversion of distal lowstand delta reservoirs (e.g. Coalinga East Extension field).« less

Sequence stratigraphy, tectonics and hydrocarbon trap geometries of Middle Tertiary strata in the southern San Joaquin Basin, California

DOE Office of Scientific and Technical Information (OSTI.GOV)

Phillips, S.; Hewlett, J.S.; Bazeley, W.J.M.

1996-12-31

Tectonic evolution of the southern San Joaquin basin exerted a fundamental control on Cenozoic sequence boundary development, reservoir, source and seal facies distribution, and hydrocarbon trap development. Spatial and temporal variations in Tertiary sequence architecture across the basin reflect differences in eastside versus westside basin-margin geometries and deformation histories. Deposition of Tertiary sequences initiated in a forearc basin setting, bounded on the east by a ramp-margin adjacent to the eroded Sierran arc complex and on the west by the imbricated accretionary wedge of the Coast Ranges thrust. The major stages of Cenozoic basin evolution are: (1) Episodic compressional folding andmore » thrusting associated with oblique convergence of the Farallon and North American plates (Late Cretaceous to Oligocene), (2) localized folding and onset of basin subsidence related to Pacific Plate reorganization, microplate formation and rotation (Oligocene to Early Miocene), (3) transtensional faulting, folding basin subsidence associated with initiation of the San Andreas transform and continued microplate rotation (Micocene to Pliocene), and (4) compressional folding, extensional and strike- slip faulting related to evolution of the Pacific-North American transform boundary (Plio- Pleistocene). Complex stratigraphic relationships within Eocene to Middle Miocene rocks provide examples of tectonic influences on sequence architecture. These include development of: (1) Tectonically enhanced sequence boundaries (Early Eocene base Domengine unconformity) and local mid-sequence angular unconformities, (2) westside-derived syntectonic {open_quotes}lowstand{close_quotes} systems (Yokut/Turitella Silt wedge and Leda Sand/Cymric/Salt Creek wedge), (3) regional seals associated with subsidence-related transgressions (Round Mountain Silt), and (4) combination traps formed by structural inversion of distal lowstand delta reservoirs (e.g. Coalinga East Extension field).« less

Lithospheric architecture of the Levant Basin (Eastern Mediterranean region): A 2D modeling approach

NASA Astrophysics Data System (ADS)

Inati, Lama; Zeyen, Hermann; Nader, Fadi Henri; Adelinet, Mathilde; Sursock, Alexandre; Rahhal, Muhsin Elie; Roure, François

2016-12-01

This paper discusses the deep structure of the lithosphere underlying the easternmost Mediterranean region, in particular the Levant Basin and its margins, where the nature of the crust, continental versus oceanic, remains debated. Crustal thickness and the depth of the lithosphere-asthenosphere boundary (LAB) as well as the crustal density distribution were calculated by integrating surface heat flow data, free-air gravity anomaly, geoid and topography. Accordingly, two-dimensional, lithospheric models of the study area are discussed, demonstrating the presence of a progressively attenuated crystalline crust from E to W (average thickness from 35 to 8 km). The crystalline crust is best interpreted as a strongly thinned continental crust under the Levant Basin, represented by two distinct components, an upper and a lower crust. Further to the west, the Herodotus Basin is believed to be underlain by an oceanic crust, with a thickness between 6 and 10 km. The Moho under the Arabian Plate is 35-40 km deep and becomes shallower towards the Mediterranean coast. It appears to be situated at depths ranging between 20 and 23 km below the Levant Basin and 26 km beneath the Herodotus Basin, based on our proposed models. At the Levantine margin, the thinning of the crust in the transitional domain between the onshore and the offshore is gradual, indicating successive extensional regimes that did not reach the beak up stage. In addition, the depth to LAB is around 120 km under the Arabian and the Eurasian Plates, 150 km under the Levant Basin, and it plunges to 180 km under the Herodotus Basin. This study shows that detailed 2D lithosphere modeling using integrated geophysical data can help understand the mechanisms responsible for the modelled lithospheric architecture when constrained with geological findings.

Facies analysis, palaeoenvironmental reconstruction and stratigraphic development of the Early Cretaceous sediments (Lower Bima Member) in the Yola Sub-basin, Northern Benue Trough, NE Nigeria

NASA Astrophysics Data System (ADS)

Sarki Yandoka, Babangida M.; Abubakar, M. B.; Abdullah, Wan Hasiah; Amir Hassan, M. H.; Adamu, Bappah U.; Jitong, John S.; Aliyu, Abdulkarim H.; Adegoke, Adebanji Kayode

2014-08-01

The Benue Trough of Nigeria is a major rift basin formed from the tension generated by the separation of African and South American plates in the Early Cretaceous. It is geographically sub-divided into Southern, Central and Northern Benue portions. The Northern Benue Trough comprises two sub-basins; the N-S trending Gongola Sub-basin and the E-W trending Yola Sub-basin. The Bima Formation is the oldest lithogenetic unit occupying the base of the Cretaceous successions in the Northern Benue Trough. It is differentiated into three members; the Lower Bima (B1), the Middle Bima (B2) and the Upper Bima (B3). Facies and their stratigraphical distribution analyses were conducted on the Lower Bima Member exposed mainly at the core of the NE-SW axially trending Lamurde Anticline in the Yola Sub-basin, with an objective to interpret the paleodepositional environments, and to reconstruct the depositional model and the stratigraphical architecture. Ten (10) lithofacies were identified on the basis of lithology, grain size, sedimentary structures and paleocurrent analysis. The facies constitute three (3) major facies associations; the gravelly dominated, the sandy dominated and the fine grain dominated. These facies and facies associations were interpreted and three facies successions were recognized; the alluvial-proximal braided river, the braided river and the lacustrine-marginal lacustrine. The stratigraphic architecture indicates a rifted (?pull-apart) origin as the facies distribution shows a progradational succession from a shallow lacustrine/marginal lacustrine (at the axial part of the basin) to alluvial fan (sediment gravity flow)-proximal braided river (gravel bed braided river) and braided river (channel and overbank) depositional systems. The facies stacking patterns depict sedimentation mainly controlled by allogenic factors of climate and tectonism.

Continentward-dipping detachment fault system and asymmetric rift structure of the Baiyun Sag, northern South China Sea

NASA Astrophysics Data System (ADS)

Zhou, Zhichao; Mei, Lianfu; Liu, Jun; Zheng, Jinyun; Chen, Liang; Hao, Shihao

2018-02-01

The rift architecture and deep crustal structure of the distal margin at the mid-northern margin of the South China Sea have been previously investigated by using deep seismic reflection profiles. However, one fundamental recurring problem in the debate is the extensional fault system and rift structure of the hyperextended rift basins (Baiyun Sag and Liwan Sag) within the distal margin because of the limited amount of seismic data. Based on new 3D seismic survey data and 2D seismic reflection profiles, we observe an array of fault blocks in the Baiyun Sag, which were tilted towards the ocean by extensional faulting. The extensional faults consistently dip towards the continent. Beneath the tilted fault blocks and extensional faults, a low-angle, high-amplitude and continuous reflection has been interpreted as the master detachment surface that controls the extension process. During rifting, the continentward-dipping normal faults evolved in a sequence from south to north, generating the asymmetric rift structure of the Baiyun Sag. The Baiyun Sag is separated from the oceanic domain by a series of structural highs that were uplifted by magmatic activity in response to the continental breakup at 33 Ma and a ridge jump to the south at 26-24 Ma. Therefore, we propose that magmatism played a significant role in the continental extension and final breakup in the South China Sea.

DOE Office of Scientific and Technical Information (OSTI.GOV)

McGregor, Hugh C. J., E-mail: hugh.mcgregor@ucsf.edu; Saeed, Maythem, E-mail: maythem.saeed@ucsf.edu; Surman, Andrew, E-mail: andrew.surman@ucsf.edu

PurposeTo investigate the feasibility of percutaneous gallbladder cryoablation (GBC) under CT guidance in a swine model with histopathologic correlation.Materials and MethodsInstitutional Animal Care and Use Committee approval was obtained for this study protocol. Five pigs underwent GBC. Under CT guidance, 3–4 cryoprobes were positioned percutaneously at the gallbladder margins. Thermocouple probes were placed percutaneously at the gallbladder fundus, neck, free wall, and gallbladder fossa. Two freeze–thaw cycles ranging from 10 to 26 min were performed. The subjects were sacrificed 5 h after cryoablation. The gallbladder and bile ducts were resected, stained, and examined microscopically.ResultsGBC was completed in all subjects. A 10-mm ablationmore » margin was achieved beyond all gallbladder walls. Thermocouple probes reached at least −20 °C. Intra-procedural body temperature decreased to a minimum of 35 °C but recovered after the procedure. Intra- and post-procedural vital signs otherwise remained within physiologic parameters. Non-target ablation occurred in the stomach and colon of the first two subjects. Histology demonstrated complete denudation of the gallbladder epithelium, hemorrhage, and edema within the muscularis layer, and preservation of the microscopic architecture of the common bile duct in all cases.ConclusionPercutaneous gallbladder cryoablation is feasible, with adequate ablation margins obtained and histologic changes demonstrating transmural necrosis. Adjacent structures included in the ablation may require conservative ablation zones, hydrodissection, or continuous saline lavage.« less

Benefits of task-shifting HIV care to nurses in terms of health-related quality of life in patients initiating antiretroviral therapy in rural district hospitals in Cameroon [Stratall Agence Nationale de Recherche sur le SIDA (ANRS) 12110/Ensemble pour une Solidarité Thérapeutique Hospitalière en Réseau (ESTHER) substudy].

PubMed

Suzan-Monti, M; Blanche, J; Boyer, S; Kouanfack, C; Delaporte, E; Bonono, R-C; Carrieri, P M; Protopopescu, C; Laurent, C; Spire, B

2015-05-01

The World Health Organization (WHO) recommends task-shifting HIV care to nurses in low-resource settings with limited numbers of physicians. However, the effect of such task-shifting on the health-related quality of life (HRQL) of people living with HIV (PLHIV) has seldom been evaluated. We aimed to investigate the effect of task-shifting HIV care to nurses on HRQL outcomes in PLHIV initiating antiretroviral therapy (ART) in rural district hospitals in Cameroon. Outcomes in PLHIV were longitudinally collected in the 2006-2010 Stratall trial. PLHIV were followed up for 24 months by nurses and/or physicians. Six HRQL dimensions were assessed during face-to-face interviews using the WHO Quality of Life (WHOQOL)-HIV BREF scale: physical health; psychological health; independence level; social relationships; environment; and spirituality/religion/personal beliefs. The degree of task-shifting was estimated using a consultant ratio (i.e. the ratio of nurse-led to physician-led visits). The effect of task-shifting and other potential correlates on HRQL dimensions was explored using a Heckman two-stage approach based on linear mixed models to adjust for the potential bias caused by missing data in the outcomes. Of 1424 visits in 440 PLHIV (70.5% female; median age 36 years; median CD4 count 188 cells/μL at enrolment), 423 (29.7%) were task-shifted to nurses. After multiple adjustment, task-shifting was associated with higher HRQL level for four dimensions: physical health [coefficient 0.7; 95% confidence interval (CI) 0.1-1.2; P = 0.01], psychological health (coefficient 0.5; 95% CI 0.0-1.0; P = 0.05), independence level (coefficient 0.6; 95% CI 0.1-1.1; P = 0.01) and environment (coefficient 0.6; 95% CI 0.1-1.0; P = 0.02). Task-shifting HIV care to nurses benefits the HRQL of PLHIV. Together with the previously demonstrated comparable clinical effectiveness of physician-based and nurse-based models of HIV care, our results support the WHO recommendation for task-shifting. © 2015 British HIV Association.

Tectonics versus eustatic control on supersequences of the Zagros Mountains of Iran

NASA Astrophysics Data System (ADS)

Heydari, Ezat

2008-04-01

At least 12 km of strata ranging in age from the latest Precambrian to the Recent are exposed in the Zagros Mountains of Iran. This sedimentary cover is characterized by distinct stratal packages separated by major unconformities forming twelve supersequences. They are informally named as: (1) Late Precambrian - Cambrian Hakhamanesh Supersequence, (2) Ordovician Kourosh Supersequence, (3) Silurian Camboojiyeh Supersequence, (4) Devonian Darioush Supersequence, (5) Mississippian - Pennsylvanian Khashayar Supersequence, (6) Permian - Triassic Ashk Supersequence, (7) Jurassic Farhad Supersequence, (8) Early Cretaceous Mehrdad Supersequence, (9) Late Cretaceous Ardavan Supersequence, (10) Paleocene - Oligocene Sassan Supersequence, (11) Oligocene - Miocene Ardeshir Supersequence, and (12) Miocene - Pleistocene Shapour Supersequence. These supersequences and their correlatives in neighboring areas have been used to infer tectonic events. The dominant interpretation has been that local or regional epeirogenic movements were responsible for the formation of these supersequences. Unconformities are considered as indications that epeirogenic movements associated with tectonic events affected the area. The present investigation provides an alternative to the established view of the Phanerozoic supersequences of the Zagros Mountains. A good correlation exists between the lithofacies of supersequences in the Zagros Mountains and the second-order eustatic sea-level changes. Deposition of deep-water, marine shales occurred during periods of eustatic sea-level rise. Platform-wide unconformities coincided with eustatic sea-level lows. In fact, supersequences of the Zagros Mountains are nearly identical to those described from the North American Craton and the Russian Platform suggesting that these stratal packages are global. These observations suggest that supersequences of the Zagros Mountains formed by second order eustatic sea-level changes and not by local or regional epeirogenic movements. Although tectonic events did not produce supersequences of the Zagros Mountains, they influenced regional lithofacies patterns through the formation of intrashelf depressions such as the Hormoz Salt Basin during the Precambrian and the Dezful Embayment and the Lorestan Basin during the Mesozoic. Tectonic events also affected sedimentation during the Tertiary collision of Arabia and the Central Iran microplate through uplift, erosion, and the formation of the Zagros Foreland Basin. The results of this investigation necessitate a re-evaluation of the role and the significance of pre-Tertiary tectonic events commonly used to interpret the geological evolution of the Zagros Mountains.

Robotic unclamped "minimal-margin" partial nephrectomy: ongoing refinement of the anatomic zero-ischemia concept.

PubMed

Satkunasivam, Raj; Tsai, Sheaumei; Syan, Sumeet; Bernhard, Jean-Christophe; de Castro Abreu, Andre Luis; Chopra, Sameer; Berger, Andre K; Lee, Dennis; Hung, Andrew J; Cai, Jie; Desai, Mihir M; Gill, Inderbir S

2015-10-01

Anatomic partial nephrectomy (PN) techniques aim to decrease or eliminate global renal ischemia. To report the technical feasibility of completely unclamped "minimal-margin" robotic PN. We also illustrate the stepwise evolution of anatomic PN surgery with related outcomes data. This study was a retrospective analysis of 179 contemporary patients undergoing anatomic PN at a tertiary academic institution between October 2009 and February 2013. Consecutive consented patients were grouped into three cohorts: group 1, with superselective clamping and developmental-curve experience (n = 70); group 2, with superselective clamping and mature experience (n = 60); and group 3, which had completely unclamped, minimal-margin PN (n = 49). Patients in groups 1 and 2 underwent superselective tumor-specific devascularization, whereas patients in group 3 underwent completely unclamped minimal-margin PN adjacent to the tumor edge, a technique that takes advantage of the radially oriented intrarenal architecture and anatomy. Primary outcomes assessed the technical feasibility of robotic, completely unclamped, minimal-margin PN; short-term changes in estimated glomerular filtration rate (eGFR); and development of new-onset chronic kidney disease (CKD) stage >3. Secondary outcome measures included perioperative variables, 30-d complications, and histopathologic outcomes. Demographic data were similar among groups. For similarly sized tumors (p = 0.13), percentage of kidney preserved was greater (p = 0.047) and margin width was narrower (p = 0.0004) in group 3. In addition, group 3 had less blood loss (200, 225, and 150ml; p = 0.04), lower transfusion rates (21%, 23%, and 4%; p = 0.008), and shorter hospital stay (p = 0.006), whereas operative time and 30-d complication rates were similar. At 1-mo postoperatively, median percentage reduction in eGFR was similar (7.6%, 0%, and 3.0%; p = 0.53); however, new-onset CKD stage >3 occurred less frequently in group 3 (23%, 10%, and 2%; p = 0.003). Study limitations included retrospective analysis, small sample size, and short follow-up. We developed an anatomically based technique of robotic, unclamped, minimal-margin PN. This evolution from selective clamped to unclamped PN may further optimize functional outcomes but requires external validation and longer follow-up. The technical evolution of partial nephrectomy surgery is aimed at eliminating global renal damage from the cessation of blood flow. An unclamped minimal-margin technique is described and may offer renal functional advantage but requires long-term follow-up and validation at other institutions. Copyright © 2015 European Association of Urology. Published by Elsevier B.V. All rights reserved.

Alpine inversion of the North African margin and delamination of its continental lithosphere

NASA Astrophysics Data System (ADS)

Roure, FrançOis; Casero, Piero; Addoum, Belkacem

2012-06-01

This paper aims at summarizing the current extent and architecture of the former Mesozoic passive margin of North Africa from North Algeria in the west up to the Ionian-Calabrian arc and adjacent Mediterranean Ridge in the east. Despite that most paleogeographic models consider that the Eastern Mediterranean Basin as a whole is still underlain by remnants of the Permo-Triassic or a younger Cretaceous Tethyan-Mesogean ocean, the strong similarities documented here in structural styles and timing of inversion between the Saharan Atlas, Sicilian Channel and the Ionian abyssal plain evidence that this portion of the Eastern Mediterranean Basin still belongs to the distal portion of the North African continental margin. A rim of Tethyan ophiolitic units can be also traced more or less continuously from Turkey and Cyprus in the east, in onshore Crete, in the Pindos in Greece and Mirdita in Albania, as well as in the Western Alps, Corsica and the Southern Apennines in the west, supporting the hypothesis that both the Apulia/Adriatic domain and the Eastern Mediterranean Basin still belong to the former southern continental margin of the Tethys. Because there is no clear evidence of crustal-scale fault offsetting the Moho, but more likely a continuous yet folded Moho extending between the foreland and the hinterland beneath the Mediterranean arcs, we propose here a new model of delamination of the continental lithosphere for the Apennines and the Aegean arcs. In this model, only the mantle lithosphere of Apulia and the Eastern Mediterranean is still locally subducted and recycled in the asthenosphere, most if not all the northern portion of the African crust and coeval Moho being currently decoupled from its former, currently delaminated and subducted mantle lithosphere.

Sediment Dynamics and Geohazards offshore Uruguay and Northern Argentina: First Results from the multi-disciplinary Meteor-Cruise M78-3

NASA Astrophysics Data System (ADS)

Krastel, Sebastian; Freudenthal, Tim; Hanebuth, Till; Preu, Benedict; Schwenck, Tilmann; Strasser, Michael; Violante, Roberto; Wefer, Gerold; Winkelmann, Daniel

2010-05-01

About 90% of the sediments generated by weathering and erosion on land get finally deposited at the ocean margins. The sediment distribution processes and landscape evolution on land are relatively well understood, but comparably little is known about the role and relative importance of marine sediment dynamics in controlling the architectural evolution of ocean margins. Important players include hemi-pelagic settling, down-slope and current-controlled along-slope sediment transport, depositional and post-depositional sedimentary processes (e.g. consolidation and diagenesis), as well as the destabilization of sediment bodies and their erosion. Submarine landslides in this context thus may represent an important sediment transport process, but also a major geo-hazard due to the increasing number of offshore constructions as well as their potential to instantaneously displace large water masses triggering waves in densely populated coastal areas. Here we present first results from a seagoing expedition that aimed at investigating the interaction processes of sediment redistribution, partitioning, deposition and diagenesis from the coast to the deep-sea along the western South-Atlantic passive continental margin. During RV Meteor Cruise M78/3 in May-July 2009 the shelf, slope and rise offshore Argentina and Uruguay have been investigated by means of hydroacoustic and seismic mapping as well as geological sampling with conventional coring tools as well as the new MARUM seafloor drill rig (MeBo) that revealed recovery of geological strata sampled from up to 50m below seafloor. The working area is characterized by a high amount of fluvial input by the Rio de la Plata river. The continental slope is relatively wide and shows average slope gradients between 1 and 2.5 but locally higher slope gradients may occur (>5). The transition for the continental rise with low slope gradients is found in ~ 3000m water depth. The working area is located in a highly dynamic oceanographic regime. Cold Antarctic water masses of the northward flowing Malvina current meet warm water masses of the southward flowing Brazil current in the working area. Various types of sediment instabilities have been imaged in geophysical and core data, documenting particularly the continental slope offshore Uruguay to be locus of frequent submarine landslides. Apart from individual landslides, however, gravitational downslope sediment transport along the continental slope is restricted to the prominent Mar del Plata Canyon and possibly to smaller canyons indentified in the bathymetric data. The location of the canyons might be controlled by tectonics. In contrast, many morphological features (e.g. progradational terraces and slope parallel scarps with scour-geometries) reveal that sediment transport is predominantly influenced/controlled by strong contour bottom currents. This suggests a significant impact of the western boundary currents on the overall architectural evolution of the margin. Future studies using the acquired geophysical, sedimentological, physical property and geochemical data will (i) quantify the relative contribution of gravitational down-slope vs. along-slope processes through time in shaping this ocean margin and how it relates to the global ocean circulation pattern and sea-level change through time, (ii) investigate depositional and post-depositional processes and how they control submarine slope stability and submarine landslide initiation and (iii) explore the interaction and relative contribution of the various processes in controlling margin evolution, sediment dynamics and geohazard off Uruguay and Northern Argentina.

Pea Compound Leaf Architecture Is Regulated by Interactions among the Genes UNIFOLIATA, COCHLEATA, AFILA, and TENDRIL-LESS

PubMed Central

Gourlay, Campbell W.; Hofer, Julie M. I.; Ellis, T. H. Noel

2000-01-01

The compound leaf primordium of pea represents a marginal blastozone that initiates organ primordia, in an acropetal manner, from its growing distal region. The UNIFOLIATA (UNI) gene is important in marginal blastozone maintenance because loss or reduction of its function results in uni mutant leaves of reduced complexity. In this study, we show that UNI is expressed in the leaf blastozone over the period in which organ primordia are initiated and is downregulated at the time of leaf primordium determination. Prolonged UNI expression was associated with increased blastozone activity in the complex leaves of afila (af), cochleata (coch), and afila tendril-less (af tl) mutant plants. Our analysis suggests that UNI expression is negatively regulated by COCH in stipule primordia, by AF in proximal leaflet primordia, and by AF and TL in distal and terminal tendril primordia. We propose that the control of UNI expression by AF, TL, and COCH is important in the regulation of blastozone activity and pattern formation in the compound leaf primordium of the pea. PMID:10948249

Model-Based Control of a Nonlinear Aircraft Engine Simulation using an Optimal Tuner Kalman Filter Approach

NASA Technical Reports Server (NTRS)

Connolly, Joseph W.; Csank, Jeffrey Thomas; Chicatelli, Amy; Kilver, Jacob

2013-01-01

This paper covers the development of a model-based engine control (MBEC) methodology featuring a self tuning on-board model applied to an aircraft turbofan engine simulation. Here, the Commercial Modular Aero-Propulsion System Simulation 40,000 (CMAPSS40k) serves as the MBEC application engine. CMAPSS40k is capable of modeling realistic engine performance, allowing for a verification of the MBEC over a wide range of operating points. The on-board model is a piece-wise linear model derived from CMAPSS40k and updated using an optimal tuner Kalman Filter (OTKF) estimation routine, which enables the on-board model to self-tune to account for engine performance variations. The focus here is on developing a methodology for MBEC with direct control of estimated parameters of interest such as thrust and stall margins. Investigations using the MBEC to provide a stall margin limit for the controller protection logic are presented that could provide benefits over a simple acceleration schedule that is currently used in traditional engine control architectures.

Mind's historicity: its hidden history.

PubMed

Pizarroso, Noemí

2013-02-01

Whereas psychological research can hardly accept the idea of a changing psychological architecture, mind's historicity seems to be commonplace among historians of psychology, at least in recent decades. Attempts to promote a convergence between psychology and history have always existed, though mainly in the margins of both disciplines. Among these attempts, there is a tradition in French psychology that remains quite marginal even to the history of the discipline and is practically unknown out of the French context. Our goal is to introduce this approach, through the work of its main architect, Ignace Meyerson, to an English speaking reader, in the light of current pleas for historicity. Developed within the core of the discipline of psychology, though in dialogue with many others disciplines, Meyerson's historical psychology appears to be more ambitious than other attempts, as it aims at studying psychological activity itself, beyond the history of its conceptualizations. It is concerned not with the analysis of fragmented, isolated, and mechanistic behaviors or cognitive process, but with the study of mind in its functioning through the multiple and changing fields of experience where human beings are involved.

Variations in fluvial style in the Westwater Canyon Member, Morrison formation (Jurassic), San Juan basin, Colorado plateau

USGS Publications Warehouse

Miall, A.D.; Turner-Peterson, C. E.

1989-01-01

Techniques of architectural element analysis and lateral profiling have been applied to the fluvial Westwater Canyon Member of the Morrison Formation (Jurassic) in southern San Juan Basin. On a large scale, the sandstone-body architecture consists mainly of a series of tabular sandstone sheets 5-15 m thick and hundreds of meters wide, separated by thin fine-grained units. Internally these sheets contain lateral accretion surfaces and are cut by channels 10-20 m deep and at least 250 m wide. On a more detailed scale, interpretations made from large-scale photomosaics show a complex of architectural elements and bounding surfaces. Typical indicators of moderate- to high-sinuosity channels (lateral accretion deposits) coexist in the same outcrop with downstream-accreted macroform deposits that are typical of sand flats of low-sinuosity, multiple-channel rivers. Broad, deep channels with gently to steeply dipping margins were mapped in several of the outcrops by carefully tracing major bounding surfaces. Locally thick accumulations of plane-laminated and low-angle cross-laminated sandstone lithofacies suggest rapid flow, probably transitional to upper flow regime conditions. Such a depositional style is most typical of ephemeral rivers or those periodically undergoing major seasonal (or more erratic) stage fluctuations, an interpretation consistent with independent mineralogical evidence of aridity. Fining-upward sequences are rare in the project area, contrary to the descriptions of Campbell (1976). The humid alluvial fan model of Galloway (1978) cannot be substantiated and, similarly, the architectural model of Campbell (1976) requires major revision. Comparisons with the depositional architecture of the large Indian rivers, such as the Ganges and Brahmaputra, still seem reasonable, as originally proposed by Campbell (1976), although there is now convincing evidence for aridity and for major stage fluctuations, which differs both from those modern rivers and Campbell's interpretation. ?? 1989.

Optimal Control Allocation with Load Sensor Feedback for Active Load Suppression, Flight-Test Performance

NASA Technical Reports Server (NTRS)

Miller, Christopher J.; Goodrick, Dan

2017-01-01

The problem of control command and maneuver induced structural loads is an important aspect of any control system design. The aircraft structure and the control architecture must be designed to achieve desired piloted control responses while limiting the imparted structural loads. The classical approach is to utilize high structural margins, restrict control surface commands to a limited set of analyzed combinations, and train pilots to follow procedural maneuvering limitations. With recent advances in structural sensing and the continued desire to improve safety and vehicle fuel efficiency, it is both possible and desirable to develop control architectures that enable lighter vehicle weights while maintaining and improving protection against structural damage. An optimal control technique has been explored and shown to achieve desirable vehicle control performance while limiting sensed structural loads to specified values. This technique has been implemented and flown on the National Aeronautics and Space Administration Full-scale Advanced Systems Testbed aircraft. The flight tests illustrate that the approach achieves the desired performance and show promising potential benefits. The flights also uncovered some important issues that will need to be addressed for production application.

Uruguay Roselli 1938 and Rosellichnus, N. Ichnogenus: Two ichnogenera for clusters of fossil bee cells

USGS Publications Warehouse

Genise, Jorge F.; Bown, Thomas M.

1996-01-01

The systematics of the fossil bee nest ichnogenus Uruguay from the Uruguayan Cretaceous or lower Tertiary is reviewed and two new ichnospecies of a new ichnogenus, Rosellichnus, are proposed for fossil bee nests from the Miocene of the United Arab Emirates and Patagonian Argentina. Uruguay contains U. auroranormae(the ich‐notype) and U. rivasi, which differs from the type ichnospecies in having clustered cells arranged in three rows, with one central and two marginal rows of subparallel cells. No bee nest architecture known to us unequivocally fits with any ichnospecies described herein. Uruguay was constructed in the subsoil and may be of halictid origin; however, its large cell size, thick cell walls, and the presence of a vestibular cell do not fit the architecture of nests of extant halictids. Rosellichnus arabicus lacks the complete cavity surrounding the cell cluster that is typical in nests of Old World halictids, but it may, nonetheless, still be of halictid origin. R. pa‐tagonicus has an architecture more similar to nests of anthophorine bees than to those of Neotropical Halictidae. Therefore, the ichnogenus Rosellichnus may include both halictid and anthophorine constructions. Although the smooth inner cell walls, spiral cell caps, and clustering of cells indicate that both Uruguay and Rosellichnus are trace fossils of bee origin, it is likely that both represent nest architectures that are no longer employed by extant bees, or those that are as yet unknown. The paleoenvironments of both the Argentine and Emirates species of Rosellichnus indicate that the trace‐makers of this ichnogenus constructed their nests in open ground sandy soils.

Joint Polar Satellite System (JPSS) Common Ground System (CGS) Technical Performance Measures of the Block 2 Architecture

NASA Astrophysics Data System (ADS)

Grant, K. D.; Panas, M.

2016-12-01

NOAA and NASA are jointly acquiring the next-generation civilian weather satellite system: the Joint Polar Satellite System (JPSS). JPSS replaced the afternoon orbit component and ground processing of NOAA's old POES system. JPSS satellites carry sensors that collect meteorological, oceanographic, climatological, and solar-geophysical observations of the earth, atmosphere, and space. The ground processing system for JPSS is known as the JPSS Common Ground System (JPSS CGS). Developed and maintained by Raytheon Intelligence, Information and Services (IIS), the CGS is a globally distributed, multi-mission system serving NOAA, NASA and their national and international partners. The CGS has demonstrated its scalability and flexibility to incorporate multiple missions efficiently and with minimal cost, schedule and risk, while strengthening global partnerships in weather and environmental monitoring. The CGS architecture has been upgraded to Block 2.0 to satisfy several key objectives, including: "operationalizing" the first satellite, Suomi NPP, which originally was a risk reduction mission; leveraging lessons learned in multi-mission support, taking advantage of newer, more reliable and efficient technologies and satisfying constraints due of the continually evolving budgetary environment. To ensure the CGS meets these needs, we have developed 48 Technical Performance Measures (TPMs) across 9 categories: Data Availability, Data Latency, Operational Availability, Margin, Scalability, Situational Awareness, Transition (between environments and sites), WAN Efficiency, and Data Recovery Processing. This paper will provide an overview of the CGS Block 2.0 architecture, with particular focus on the 9 TPM categories listed above. We will describe how we ensure the deployed architecture meets these TPMs to satisfy our multi-mission objectives with the deployment of Block 2.0.

Architecture of the human renal inner medulla and functional implications.

PubMed

Wei, Guojun; Rosen, Seymour; Dantzler, William H; Pannabecker, Thomas L

2015-10-01

The architecture of the inner stripe of the outer medulla of the human kidney has long been known to exhibit distinctive configurations; however, inner medullary architecture remains poorly defined. Using immunohistochemistry with segment-specific antibodies for membrane fluid and solute transporters and other proteins, we identified a number of distinctive functional features of human inner medulla. In the outer inner medulla, aquaporin-1 (AQP1)-positive long-loop descending thin limbs (DTLs) lie alongside descending and ascending vasa recta (DVR, AVR) within vascular bundles. These vascular bundles are continuations of outer medullary vascular bundles. Bundles containing DTLs and vasa recta lie at the margins of coalescing collecting duct (CD) clusters, thereby forming two regions, the vascular bundle region and the CD cluster region. Although AQP1 and urea transporter UT-B are abundantly expressed in long-loop DTLs and DVR, respectively, their expression declines with depth below the outer medulla. Transcellular water and urea fluxes likely decline in these segments at progressively deeper levels. Smooth muscle myosin heavy chain protein is also expressed in DVR of the inner stripe and the upper inner medulla, but is sparsely expressed at deeper inner medullary levels. In rodent inner medulla, fenestrated capillaries abut CDs along their entire length, paralleling ascending thin limbs (ATLs), forming distinct compartments (interstitial nodal spaces; INSs); however, in humans this architecture rarely occurs. Thus INSs are relatively infrequent in the human inner medulla, unlike in the rodent where they are abundant. UT-B is expressed within the papillary epithelium of the lower inner medulla, indicating a transcellular pathway for urea across this epithelium. Copyright © 2015 the American Physiological Society.

High-resolution and Deep Crustal Imaging Across The North Sicily Continental Margin (southern Tyrrhenian Sea)

NASA Astrophysics Data System (ADS)

Agate, M.; Bertotti, G.; Catalano, R.; Pepe, F.; Sulli, A.

Three multichannel seismic reflection profiles across the North Sicily continental mar- gin have been reprocessed and interpreted. Data consist of an unpublished high pene- tration seismic profile (deep crust Italian CROP Project) and a high-resolution seismic line. These lines run in the NNE-SSW direction, from the Sicilian continental shelf to the Tyrrhenian abyssal plain (Marsili area), and are tied by a third, high penetration seismic line MS104 crossing the Sisifo High. The North Sicily continental margin represents the inner sector of the Sicilian-Maghrebian chain that is collapsed as con- sequence of extensional tectonics. The chain is formed by a tectonic wedge (12-15 km thick. It includes basinal Meso-Cenozoic carbonate units overthrusting carbonate platform rock units (Catalano et al., 2000). Presently, main culmination (e.g. Monte Solunto) and a number of tectonic depressions (e.g. Cefalù basin), filled by >1000 m thick Plio-Pleistocene sedimentary wedge, are observed along the investigated tran- sect. Seismic attributes and reflector pattern depicts a complex crustal structure. Be- tween the coast and the M. Solunto high, a transparent to diffractive band (assigned to the upper crust) is recognised above low frequency reflective layers (occurring be- tween 9 and 11 s/TWT) that dips towards the North. Their bottom can be correlated to the seismological (African?) Moho discontinuity which is (26 km deep in the Sicilian shelf (Scarascia et al., 1994). Beneath the Monte Solunto ridge, strongly deformed re- flectors occurring between 8 to 9.5 s/TWT (European lower crust?) overly the African (?) lower crust. The resulting geometry suggests underplating of the African crust respect to the European crust (?). The already deformed crustal edifice is dissected by a number of N-dipping normal faults that open extensional basins and are associ- ated with crustal thinning. The Plio-Pleistocene fill of the Cefalù basin can be subdi- vided into three subunits by well-developed unconformities. The stratal pattern of the lower subunit (Early Pliocene?) points out thrust-top basin. The intermediate subunit (Middle-Late Pliocene?) shows a wide sedimentary lateral accretion with syntectonic growth geometries. Upper Pliocene layers are overlain by well-stratified sediments of supposedly Pleistocene to Recent age, which drape and smooth underlying features (Pepe et al., 2000). Crustal thinning is (2 in the Cefalù basin and reach (3.54 north of Sisifo volcano, where crustal separation occurs and oceanic crust emplaced (Marsili 1 basin). In this area the Moho is located at (8 s/TWT, corresponding to 10-km depth. References Catalano R., Franchino A., Merlini S. e Sulli A., 2000. Mem. Soc. Geol. It., 55, 5-16. Pepe F., Bertotti G., Cella F. Marsella E., 2000. Tectonics, 19, 241-257. Scarascia S., Lozej A. Cassinis R., 1994. Boll. Geof. Teor. Appl., 36 (141-144), 5-19. 2

Depositional architecture and evolution of inner shelf to shelf edge delta systems since the Late Oliocene and their respone to the tectonic and sea level change, Pear River Mouth Basin, northern South China Sea

NASA Astrophysics Data System (ADS)

Lin, Changsong; Zhang, Zhongtao; liu, Jingyan; Jiang, Jing

2016-04-01

The Pear River Mouth Basin is located in the northern continent margin of the South China Sea. Since the Late Oligocene, the long-term active fluvial systems (Paleo-Zhujiang) from the western basin margin bebouched into the northern continental margin of the South China Sea and formed widespread deltaic deposits in various depositional geomorphologies and tectonic settings. Based of integral analysys of abundant seismic, well logging and drilling core data, Depositional architecture and evolution of these delta systems and their respone to the tectonic and sea level change are documented in the study. There are two basic types of the delta systems which have been recognized: inner shelf delta deposited in shallow water enviroments and the outer shelf or shelf-edge delta systems occurred in deep water settings. The paleowater depths of these delta systems are around 30 to 80m (inner shelf delta) and 400-1000m (shelf-edge delta) estimated from the thickness (decompaction) of the delta front sequences. The study shows that the inner shelf delta systems are characterized by relatively thin delta forests (20-40m), numereous stacked distributary channel fills, relative coarse river mouth bar deposits and thin distal delta front or distal bar and prodelta deposits. In contrast, the outer shelf or shelf edge delta systems are characteristic of thick (300-800m) and steep (4-60) of deltaic clinoforms, which commonly display in 3D seismic profiles as "S" shape reflection. Large scale soft-sediment deformation structures, slump or debris flow deposits consisting mainly of soft-sediment deformed beds, blocks of sandstones and siltstones or mudstones widely developed in the delta front deposits. The shelf edge delta systems are typically associated with sandy turbidite fan deposits along the prodelta slopes, which may shift basinwards as the progradation of the delta systems. The delta systems underwent several regional cycles of evolution from inner shelf deltas to shelf edge deltas since the Late Oligocene in the study area, and this is consistent with relative sea level changes constrained by interplay of tectonic subsidence or global sea level change and sediment supply. The shelf-edge delta sandy deposits and the associated prodelta turbidite fan systems are the most important oil/gas bearing reservoirs in the continental slope area.

Morphology and Neurochemistry of Rabbit Iris Innervation

PubMed Central

He, Jiucheng; Bazan, Haydee E.P.

2016-01-01

The aim of this study was to map the entire nerve architecture and sensory neuropeptide content of the rabbit iris. Irises from New Zealand rabbits were stained with antibodies against neuronal-class βIII-tubulin, calcitonin gene-related peptide (CGRP) and substance P (SP), and whole-mount images were acquired to build a two-dimensional view of the iridal nerve architecture. After taking images in time-lapse mode, we observed thick nerves running in the iris stroma close to the anterior epithelia, forming four to five stromal nerve rings from the iris periphery to the pupillary margin and sub-branches that connected with each other, constituting the stromal nerve plexus. In the anterior side, fine divisions derivated from the stromal nerves, forming a nerve network-like structure to innervate the superficial anterior border layer, with the pupillary margin having the densest innervation. In the posterior side, the nerve bundles ran along with the pupil dilator muscle in a radial pattern. The morphology of the iris nerves on both sides changed with pupil size. To obtain the relative content of the neuropeptides in the iris, the specimens were double stained with βIII-tubulin and CGRP or SP antibodies. Relative nerve fiber densities for each fiber population were assessed quantitatively by computer-assisted analysis. On the anterior side, CGRP-positive nerve fibers constituted about 61%, while SP-positive nerves constitute about 30.5%, of the total nerve content, which was expressed as βIII tubulin-positive fibers. In addition, in the anterior stroma of the collarette region, there were non-neuronal cells that were positive for SP. On the posterior side, CGRP-positive nerve fibers were about 69% of total nerve content, while SP constituted only up to 20%. Similarly, in the trigeminal ganglia (TG), the number of CGRP-positive neurons significantly outnumbered those that were positive for SP. Also, all the SP-positive neurons were labeled with CGRP. This is the first study to provide a two-dimensional whole mount and a cross-sectional view of the entire iris nerve architecture. Considering the anatomical location, the high expression of CGRP and SP suggests that these neuropeptides may play a role in the pathogenesis of anterior uveitis, glaucoma, cataracts and chronic ocular pain. PMID:25752697

Morphology and neurochemistry of rabbit iris innervation.

PubMed

He, Jiucheng; Bazan, Haydee E P

2015-06-01

The aim of this study was to map the entire nerve architecture and sensory neuropeptide content of the rabbit iris. Irises from New Zealand rabbits were stained with antibodies against neuronal-class βIII-tubulin, calcitonin gene-related peptide (CGRP) and substance P (SP), and whole-mount images were acquired to build a two-dimensional view of the iridal nerve architecture. After taking images in time-lapse mode, we observed thick nerves running in the iris stroma close to the anterior epithelia, forming four to five stromal nerve rings from the iris periphery to the pupillary margin and sub-branches that connected with each other, constituting the stromal nerve plexus. In the anterior side, fine divisions derivated from the stromal nerves, forming a nerve network-like structure to innervate the superficial anterior border layer, with the pupillary margin having the densest innervation. In the posterior side, the nerve bundles ran along with the pupil dilator muscle in a radial pattern. The morphology of the iris nerves on both sides changed with pupil size. To obtain the relative content of the neuropeptides in the iris, the specimens were double stained with βIII-tubulin and CGRP or SP antibodies. Relative nerve fiber densities for each fiber population were assessed quantitatively by computer-assisted analysis. On the anterior side, CGRP-positive nerve fibers constituted about 61%, while SP-positive nerves constitute about 30.5%, of the total nerve content, which was expressed as βIII tubulin-positive fibers. In addition, in the anterior stroma of the collarette region, there were non-neuronal cells that were positive for SP. On the posterior side, CGRP-positive nerve fibers were about 69% of total nerve content, while SP constituted only up to 20%. Similarly, in the trigeminal ganglia (TG), the number of CGRP-positive neurons significantly outnumbered those that were positive for SP. Also, all the SP-positive neurons were labeled with CGRP. This is the first study to provide a two-dimensional whole mount and a cross-sectional view of the entire iris nerve architecture. Considering the anatomical location, the high expression of CGRP and SP suggests that these neuropeptides may play a role in the pathogenesis of anterior uveitis, glaucoma, cataracts and chronic ocular pain. Copyright © 2015 Elsevier Ltd. All rights reserved.

Performance and role of the breast lesion excision system (BLES) in small clusters of suspicious microcalcifications.

PubMed

Scaperrotta, Gianfranco; Ferranti, Claudio; Capalbo, Emanuela; Paolini, Biagio; Marchesini, Monica; Suman, Laura; Folini, Cristina; Mariani, Luigi; Panizza, Pietro

2016-01-01

To assess the diagnostic performance of the BLES as a biopsy tool in patients with ≤ 1 cm clusters of BIRADS 4 microcalcifications, in order to possibly avoid surgical excision in selected patients. This is a retrospective study of 105 patients undergone to stereotactic breast biopsy with the BLES. It excises a single specimen containing the whole mammographic target, allowing better histological assessment due to preserved architecture. Our case series consists of 41 carcinomas (39%) and 64 benign lesions (61%). Cancer involved the specimen margins in 20/41 cases (48.8%) or was close to them (≤ 1 mm) in 14 cases (34.1%); margins were disease-free in only 7 DCIS (17.1%). At subsequent excision of 39/41 malignant cases, underestimation occurred for 5/32 DCIS (15.6%), residual disease was found in 15/39 cancers (38.5%) and no cancer in 19/39 cases (48.7%). For DCIS cases, no residual disease occurred for 66.7% G1-G2 cases and for 35.3% G3 cases (P=0.1556) as well as in 83.3%, 40.0% and 43.8% cases respectively for negative, close and positive BLES margins (P=0.2576). The BLES is a good option for removal of small clusters of breast microcalcifications, giving better histological interpretation, lower underestimation rates and possibly reducing the need of subsequent surgical excision in selected patients. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

The Connemara Fan: a major glacial grounding line fan west of Ireland

NASA Astrophysics Data System (ADS)

McCarron, Stephen; Praeg, Daniel; Monteys, Xavier; Scott, Gill

2014-05-01

Glacigenic topography on the mid-shelf (~130-350 m water depth) west of Galway, Ireland appears to have the morphological form, internal architecture and sediments associated with a large glacial grounding-line fan. Seismic data collected in 2009 and 2012 (during the GLAMAR and GATEWAYS 1 campaigns) reveal that the broad, arcuate ridges of the 'Olex moraine' form the landward part of a fan system which prograded beyond the mid-shelf break (defining the outer margin of the 'Clare Platform') westwards into the Porcupine Seabight. The topography is comparable to larger shelf-edge trough-mouth fans found further north along the same margin, however no discernible 'trough' has been identified on the Clare Platform. The ridge and fan topographic assemblage is renamed the 'Connemara Fan' in its entirety, based on its genetic relations and geographic location due west of Connemara, western Ireland. A macrofossil recovered from within a debris flow on the outer fan slope comprised of remobilised plumites dates to ~ 20 ka Cal B.P., indicating sediment reworking downslope following deglacial sediment input to at least that time. The Connemara Fan is the most southerly glacigenic fan identified along the north-east Atlantic margin. Its identification also adds to our knowledge of possibly multiple generations of ice sheets feeding onto the Irish shelf from west-central Ireland and the occurrence of ice sheet geometries and dynamics that evacuated ice, melt-water and sediment (ice streams?) westwards across the Clare Platform during past glaciations.

Matching conjugate volcanic rifted margins: 40Ar/ 39Ar chrono-stratigraphy of pre- and syn-rift bimodal flood volcanism in Ethiopia and Yemen

NASA Astrophysics Data System (ADS)

Ukstins, Ingrid A.; Renne, Paul R.; Wolfenden, Ellen; Baker, Joel; Ayalew, Dereje; Menzies, Martin

2002-05-01

40Ar/ 39Ar dating of mineral separates and whole-rock samples of rhyolitic ignimbrites and basaltic lavas from the pre- and syn-rift flood volcanic units of northern Ethiopia provides a temporal link between the Ethiopian and Yemen conjugate rifted volcanic margins. Sixteen new 40Ar/ 39Ar dates confirm that basaltic flood volcanism in Ethiopia was contemporaneous with flood volcanism on the conjugate margin in Yemen. The new data also establish that flood volcanism initiated prior to 30.9 Ma in Ethiopia and may predate initiation of similar magmatic activity in Yemen by ˜0.2-2.0 Myr. Rhyolitic volcanism in Ethiopia commenced at 30.2 Ma, contemporaneous with the first rhyolitic ignimbrite unit in Yemen at ˜30 Ma. Accurate and precise 40Ar/ 39Ar dates on initial rhyolitic ignimbrite eruptions suggest that silicic flood volcanism in Afro-Arabia post-dates the Oligocene Oi2 global cooling event, ruling out a causative link between these explosive silicic eruptions (with individual volumes ≥200 km 3) and climatic cooling which produced the first major expansion of the Antarctic ice sheets. Ethiopian volcanism shows a progressive and systematic younging from north to south along the escarpment and parallel to the rifted margin, from pre-rift flood volcanics in the north to syn-rift northern Main Ethiopian Rift volcanism in the south. A dramatic decrease in volcanic activity in Ethiopia between 25 and 20 Ma correlates with a prominent break-up unconformity in Yemen (26-19 Ma), both of which mark the transition from pre- to syn-rift volcanism (˜25-26 Ma) triggered by the separation of Africa and Arabia. The architecture of the Ethiopian margin is characterized by accumulation and preservation of syn-rift volcanism, while the Yemen margin was shaped by denudational unloading and magmatic starvation as the Arabian plate rifted away from the Afar plume. A second magmatic hiatus and angular unconformity in the northern Main Ethiopian Rift is evident at 10.6-3.2 Ma, and is also observed throughout the Arabian plate in Jordanian, Saudi Arabian and Yemeni intraplate volcanic fields and is possibly linked to tectonic re-organization and initiation of sea floor spreading in the Gulf of Aden and the Red Sea at 10 and 5 Ma, respectively.

Late tectonic uplift of an inverted oceanic basin in South East Asia: the case of Palawan Island (western Philippines)

NASA Astrophysics Data System (ADS)

Meresse, F.; Savva, D.; Pubellier, M.; Steuer, S.; Franke, D.; Cordey, F.; Muller, C.; Sapin, F.; Mouly, B.; Auxiètre, J.-L.

2012-04-01

The elongated island of Palawan, bounded by two marginal basins, the South China Sea to the North and the Sulu Sea to the South is composed of remnants of an inverted basin (Proto-South China Sea) thrusted onto the margin of a continental terrane which rifted away from the Chinese-Vietnamese margin. Based on field observations coupled with seismic and drill-holes data, our study focuses on the structural architecture of the island in order to decipher the geodynamic evolution of the southern margin of the South China Sea. Structurally, the Palawan Island consists of: (i) the Palawan wedge, which extends towards the South China Sea is composed of deformed slope to deep ocean deposits of Cretaceous (north Palawan) to Tertiary (central and south Palawan) ages. This accretionnary wedge is characterized by small wavelength folds of mainly NE-SW trend. Offshore, the unconformable Middle-Late Miocene Tabon limestones unit postdates the last stages of the Palawan wedge growth/setting; (ii) On top of this wedge lie thrust slices of ophiolite bodies comprising ribbon cherts of Albian age as indicated by radiolarians.; these bodies are likely to be relicts of the now-subducted Proto South China Sea; (iii) The central and southern parts of the Palawan island are characterized by a large wavelength antiform of NE-SW trend. This structure is sealed by the slightly tilted Early Pliocene marls unit; (iv) The island also presents necking zones bordered by N-S trending transform faults. This area witnessed the geodynamic evolution of the South East Asia which consists of a succession of opening/closure of oceanic basins and block accretions. The Palawan Island therefore results of the closing of the Proto-South China Sea which once formed both the Palawan accretionary wedge and the overlying ophiolite tectonic slices. During a later compressive event, the rifted continental margin which composes the basement of the Island was inverted, inducing the uplift and the large scale folding of the Palawan Island. In a final stage, the strain relaxing results in the formation of the necking zones, probably reactivating the inherited transform faults of the Proto-South China Sea. Keywords: Palawan Island; South China Sea; oceanic basin; inverted margin; Ophiolite.

Architecture of ductile-type passive margins: Geological constraints from the inverted Cretaceous basin of the North-Pyrenean Zone (`Chaînons Béarnais', Western Pyrenees)

NASA Astrophysics Data System (ADS)

Corre, B.; Lagabrielle, Y.; Labaume, P.; Lahfid, A.; Boulvais, P.; Bergamini, G.; Fourcade, S.; Clerc, C. N.; Asti, R.

2017-12-01

Subcontinental lithospheric mantle rocks are exhumed at the foot of magma-poor distal passive margins as a response to extreme stretching of the continental crust. The North-Pyrenean Zone (NPZ) exposes remnants of such extremely stretched paleo-passive margin that represent field analogues to study the processes of continental crust thinning and mantle exhumation. The NPZ results from the inversion of basins opened between the Iberia and Europa plates during Albo-Cenomanian times. The Chaînons Béarnais belt displays a fold-and-thrust structure involving the Mesozoic sedimentary cover associated with peridotite bodies in tectonic contact with Paleozoic basement lenses of small size. Continental extension developed under hot thermal conditions, as demonstrated by the syn-metamorphic Cretaceous ductile deformation affecting both the crustal basement and the Mesozoic cover. In this study, we present structural and geochemical data providing constraints to reconstruct the evolution of this paleo-margin. Field work confirms that the Mesozoic cover is intimately associated with mantle rocks and thin tectonic lenses of middle crust. Micro-structural studies show that the greenschist facies ductile deformation in the crust produced a mylonitic foliation which is always parallel to the crust/mantle contact. The crust/mantle detachment fault is a major shear zone characterized by anastomosed shear bands. It also shows that the pre-rift cover was detached from its bedrock at the Keuper evaporites level and was welded to mantle rocks during their exhumation at the foot of the margin. We show that: (i) the boudinaged pre-rift sediments have undergone drastic syn-metamorphic thinning with the genesis of a S0/S1 foliation and, (ii) the Paleozoic basement has been ductilely deformed, into thin tectonic lenses that remained welded to the exhumed mantle rocks. The ductile behavior is related to the presence of a thick pre- and syn-rift cover acting as an efficient thermal blanket. This new geological data set highlights important characteristics of ductile-type hyper-extended passive margin. Finally, we stress that studying field analogues represents a major tool to better understand the mechanisms of crustal thinning associated with mantle exhumation and their structural inheritance during tectonic inversion.

Digital outcrop model of stratigraphy and breccias of the southern Franklin Mountains, El Paso, Texas

USGS Publications Warehouse

Bellian, Jerome A.; Kerans, Charles; Repetski, John E.; Derby, James R.; Fritz, R.D.; Longacre, S.A.; Morgan, W.A.; Sternbach, C.A.

2012-01-01

The breccias of the SFM were previously described as the result of collapsed paleocaves that formed during subaerial exposure related to the Sauk-Tippecanoe unconformity. A new approach in this work uses traditional field mapping combined with high-resolution (1-m [3.3-ft] point spacing) airborne light detection and ranging (LIDAR) data over 24 km2 (9 mi2) to map breccia and relevant stratal surfaces. Airborne LIDAR data were used to create a digital outcrop model of the SFM from which a detailed (1:2000 scale) geologic map was created. The geologic map includes formation, fault, and breccia contacts. The digital outcrop model was used to interpret three-dimensional spatial relationships of breccia bodies with respect to the current understanding of the tectonic and stratigraphic evolution of the SFM. The data presented here are used to discuss potential stratigraphic, temporal, and tectonic controls on the formation of caves within the study area that eventually collapsed to form the breccias currently exposed in outcrop.

Giant Subaqueous Pyroclastic-Flow Deposits Revealed: Sedimentological Revision of the Holocene Outcrops of Izu-Oshima Island, Japan

NASA Astrophysics Data System (ADS)

Hemmi, R.; Yoshida, S.; Nemoto, Y.; Kotake, N.

2010-12-01

The early-to-middle Holocene outcrops of Izu-Oshima island, 100 km SSW of Tokyo, comprise sand- to gravel-size pyroclasts, and exhibit undulating layered structures, with each wavelet typically measuring 5-10 m high. These outcrops were traditionally interpreted as exemplary subaerial "ash-fall" deposits in volcanology textbooks (e.g. Schmincke 2006). Our detailed sedimentological analyses, however, have revealed that it is of pyroclastic density-current origin, the majority of which formed in shallow-marine settings. The present study focuses on the outcrops along the western coast of the Island, where the three-dimensional architecture of the outcrops is superbly exposed, and the existing archaeological framework provides a reliable chronostratigraphic control. The outcrops contain abundant compound bedforms, where small bedforms (dunes/antidunes) occur within the larger bedforms. The compound bedforms exhibit four-fold hierarchy (ranks 1 to 4), and bedforms for each scale display dominantly upstream-accreting geometry. The largest scale (Rank 1) of these bedforms show wavy parallel-bedding geometry (each wavelet typically measuring 5-10 m high and 50-100 m wide). We interpreted the large-scale architecture as sediment waves (gigantic antidunes) similar to the one reported from the shallow-marine deposits associated with AD 79 Mt. Vesuvius eruptions (Milia et al. 2008). Moreover, we have identified crustacean burrows and other trace fossils indicative of a nearshore shallow-marine environment. The pervasive occurrence of these fossils throughout the outcrops and abundant water-escape structures also suggests their subaqueous origin. On the other hand, evidence of subaerial deposition (e.g., paleosols and rootlets) or subaerial reworking (e.g., lahar) is absent, except for some spots on several regional unconformities that divide 10’s-m-thick sediment-wave deposits. On some of these unconformities, ribbon- to fan-shaped lava and/or ancient human-dwelling sites (5.0-7.5 ka) are locally present. These observations suggest that the deposition of the pyroclastic and lava flow occurred near the coastline, with rapid fluctuations of relative sea level. Earlier workers suggested that these outcrops were “subaerial ash-fall” deposits, with each dm-thick layer representing a small eruption that occurred at about 150-year interval from 20 ka to 5 ka, with the total number of eruptions reaching or possibly exceeding 100 (Tazawa 1980). However, we suggest that these layers form several 10’s-m-thick unconformity-bounded units (sediment waves). Together with the abundant shallow-marine trace fossils, we believe that these outcrops are of subaqueous pyroclastic-flow origin, recording less frequent but much bigger catastrophic eruptions than previously thought. Without recognizing the stratal packaging patterns on the 2-D/3-D vertical cross-sections, these outcrops can easily be mistaken for ash-fall deposits, and the magnitude of eruptions can be vastly underestimated.

3D multi-view convolutional neural networks for lung nodule classification

PubMed Central

Kang, Guixia; Hou, Beibei; Zhang, Ningbo

2017-01-01

The 3D convolutional neural network (CNN) is able to make full use of the spatial 3D context information of lung nodules, and the multi-view strategy has been shown to be useful for improving the performance of 2D CNN in classifying lung nodules. In this paper, we explore the classification of lung nodules using the 3D multi-view convolutional neural networks (MV-CNN) with both chain architecture and directed acyclic graph architecture, including 3D Inception and 3D Inception-ResNet. All networks employ the multi-view-one-network strategy. We conduct a binary classification (benign and malignant) and a ternary classification (benign, primary malignant and metastatic malignant) on Computed Tomography (CT) images from Lung Image Database Consortium and Image Database Resource Initiative database (LIDC-IDRI). All results are obtained via 10-fold cross validation. As regards the MV-CNN with chain architecture, results show that the performance of 3D MV-CNN surpasses that of 2D MV-CNN by a significant margin. Finally, a 3D Inception network achieved an error rate of 4.59% for the binary classification and 7.70% for the ternary classification, both of which represent superior results for the corresponding task. We compare the multi-view-one-network strategy with the one-view-one-network strategy. The results reveal that the multi-view-one-network strategy can achieve a lower error rate than the one-view-one-network strategy. PMID:29145492

Qualitative and quantitative comparison of colonic microendoscopy image features to histopathology

NASA Astrophysics Data System (ADS)

Prieto, Sandra P.; Powless, Amy J.; Lai, Keith; Laryea, Jonathan A.; Mizell, Jason S.; Muldoon, Timothy J.

2015-03-01

Colorectal cancer is the second leading cause of cancer deaths in the United States, affecting more than 130,000 Americans every year1. Determining tumor margins prior to surgical resection is essential to providing optimal treatment and reducing recurrence rates. Colorectal cancer recurrence can occur in up to 20% of cases, commonly within three years after curative treatment. Typically, when colorectal cancers are resected, a margin of normal tissue on both sides of the tumor is required. The minimum margin required for colon cancer is 5 cm and for the lower rectum 2 cm. However, usually more normal tissue is taken on both sides of the tumor because the blood supply to the entire segment is removed with the surgery and therefore the entire segment must be removed. Anastomotic recurrences may result from inadequate margins. Pathologists look at the margins to ensure that there is no residual tumor and this is usually documented in the pathology report. We have developed a portable, point-of-care fiber bundle microendoscopy imaging system for detection of abnormalities in colonic epithelial microstructure. The system comprises a laptop, a modified fiber bundle image guide with a 1mm active area diameter and custom LabVIEW interface, and is approved for imaging surgically resected colon tissue at the University of Arkansas for Medical Sciences. The microendoscopy probe provides high-resolution images of superficial epithelial histology in real-time to assist surgical guidance and to localize occult regions of dysplasia which may not be visible. Microendoscopy images of freshly resected human colonic epithelium were acquired using the microendoscopy device and subsequently mosaicked using custom post-processing software. Architectural changes in the glands were mapped to histopathology H&E slides taken from the precise location of the microendoscopy images. Qualitatively, glandular distortion and placement of image guide was used to map normal and dysplastic areas of the colonic tumor and surrounding region from microendoscopy images to H&E slides. Quantitative metrics for correlating images were also explored and were obtained by analyzing glandular diameter and spatial distribution as well as image texture.

Seismic stratigraphy of the Mianwali and Bannu depressions, north-western Indus foreland basin

NASA Astrophysics Data System (ADS)

Farid, Asam; Khalid, Perveiz; Ali, Muhammad Y.; Iqbal, Muhammad Asim; Jadoon, Khan Zaib

2017-11-01

Regional seismic reflection profiles, deep exploratory wells, and outcrop data have been used to study the structure and stratigraphic architecture of the Mianwali and Bannu depressions, north-western Indus foreland basin. Synthetic seismograms have been used to identify and tie the seismic horizons to the well data. Nine mappable seismic sequences are identified within the passive and active margin sediments. In general, the Mianwali and Bannu depressions deepens towards north due to the flexure generated by the loading and southward shifting of the thrust sheets of the North-western Himalayan Fold and Thrust Belt. The seismic profiles show a classic wedge shaped foreland basin with a prominent angular unconformity which clearly differentiates the active and passive margin sediments. The onlap patterns in the Late Cretaceous sediments suggest the initial onset of foreland basin formation when the Indian Plate collided with Eurasian Plate. As the collision progressed, the lithospheric flexure caused an uplift along the flexural bulge which resulted in onlaps within the Paleocene and Eocene sequences. The tectonic activity reached to its maximum during Oligocene with the formation of a prominent unconformity, which caused extensive erosion that increases towards the flexural bulge.

Structural geology of the proposed site area for a high-level radioactive waste repository, Yucca Mountain, Nevada

USGS Publications Warehouse

Potter, C.J.; Day, W.C.; Sweetkind, D.S.; Dickerson, R.P.

2004-01-01

Geologic mapping and fracture studies have documented the fundamental patterns of joints and faults in the thick sequence of rhyolite tuffs at Yucca Mountain, Nevada, the proposed site of an underground repository for high-level radioactive waste. The largest structures are north-striking, block-bounding normal faults (with a subordinate left-lateral component) that divide the mountain into numerous 1-4-km-wide panels of gently east-dipping strata. Block-bounding faults, which underwent Quaternary movement as well as earlier Neogene movement, are linked by dominantly northwest-striking relay faults, especially in the more extended southern part of Yucca Mountain. Intrablock faults are commonly short and discontinuous, except those on the more intensely deformed margins of the blocks. Lithologic properties of the local tuff stratigraphy strongly control the mesoscale fracture network, and locally the fracture network has a strong influence on the nature of intrablock faulting. The least faulted part of Yucca Mountain is the north-central part, the site of the proposed repository. Although bounded by complex normal-fault systems, the 4-km-wide central block contains only sparse intrablock faults. Locally intense jointing appears to be strata-bound. The complexity of deformation and the magnitude of extension increase in all directions away from the proposed repository volume, especially in the southern part of the mountain where the intensity of deformation and the amount of vertical-axis rotation increase markedly. Block-bounding faults were active at Yucca Mountain during and after eruption of the 12.8-12.7 Ma Paintbrush Group, and significant motion on these faults postdated the 11.6 Ma Rainier Mesa Tuff. Diminished fault activity continued into Quaternary time. Roughly half of the stratal tilting in the site area occurred after 11.6 Ma, probably synchronous with the main pulse of vertical-axis rotation, which occurred between 11.6 and 11.45 Ma. Studies of sequential formation of tectonic joints, in the context of regional paleostress studies, indicate that north- and northwest-striking joint sets formed coevally with the main faulting episode during regional east-northeast-west-southwest extension and that a prominent northeast-striking joint set formed later, probably after 9 Ma. These structural analyses contribute to the understanding of several important issues at Yucca Mountain, including potential hydrologic pathways, seismic hazards, and fault-displacement hazards. ?? 2004 Geological Society of America.

Structural characteristics and collapse mechanism of the late Cretaceous Geumseongsan Caldera, SE Korea

NASA Astrophysics Data System (ADS)

Lee, S.; Cheon, Y.; Lee, Y.; Son, M.

2017-12-01

The Geumseongsan caldera provides an opportunity to understand the structural evolution of volcanic collapse and the role of paleostress. We focus on structural elements of the exhumed caldera floor to interpret the collapse mechanism. The caldera shows an NNW-trending elliptical shape (8×12 km). Basaltic and rhyolitic rocks are situated in the central high of the caldera, while pre-volcanic sedimentary rocks in the perimetric lowland of the volcanic rocks. Stratal attitudes change sharply from the outside to the inside of caldera bounded with a sub-vertical ring fault. The outside strata show a homocline toward SE about 15°, whereas the inside is divided into four structural domains (NE-, NW-, SE-, and SW-domains) based on the changing attitudes. The strata in NW- and SE-domains dip toward SE and NW, respectively, making an overall synclinal fold. While NE- and SW-domains comprise re-oriented, folded strata, which generally have NE- and SW-trending axes plunging toward the center. In addition, extensional and contractional structures occur distinctively in NW- and SE-domains and in NE- and SW-domains, respectively, indicating an axisymmetric deformation around NE-SW axis. The results indicate that higher horizontal mass movement toward the center occurred in NW- and SE-domains than in NE- and SW-domains while vertical mass movement was more active in the latter. This axisymmetric deformation could be produced by regional stress during the volcanic activity, which affected the collapse pattern of caldera floor. The regional stress field during the late Cretaceous is known as NW-SE horizontal maximum and NE-SW horizontal minimum stresses due to the oblique subduction of proto-Pacific Plate underneath Eurasian Plate. NNW-trending elliptical shape of the caldera is interpreted to have formed under the influence of this stresses, like a tension gash. The NW-SE maximum stress possibly acted to resist vertical displacement along the marginal fault of NW- and SE-domains, whereas the NE-SW minimum stress enabled easier vertical movement along that of NE- and SW-domains. This differential movement is interpreted to have caused a great quantity of mass transportation toward NW and SE, which concentrated the extensional and contractional structures in NW- and SE-domains and in NE- and SW-domains, respectively.

A Miocene wave-dominated estuarine system in the Paraíba Basin, northeastern Brazil

NASA Astrophysics Data System (ADS)

Gandini, Rosana; Rossetti, Dilce de Fátima; Netto, Renata Guimarães; Góes, Ana Maria

2017-11-01

A number of publications have documented the effect of the Miocene transgression on several coasts of the world. However, this event is incompletely documented along the Brazilian margin, despite the existence of an impressive record of Miocene deposits exposed mostly as several coastal cliffs along more than 5000 km of distance. The transgressive nature of Miocene deposits, so far recognized only in a few localities of northeastern Brazil, needs to be amplified in order to better characterize the impact of the Miocene transgression in eastern South America. In this work, we provide facies analysis of early/middle Miocene strata exposed in the Paraíba Basin, northeastern Brazil, aiming reconstruct the depositional paleoenvironments and analyze their evolution within the context of relative sea-level fluctuations data. The results revealed deposits characterized by several features that were related to the action of tidal currents, such as alternating thicker/thinner forest packages, abundant reactivation surfaces, mud drapes and oppositely-dipping (herringbone) cross sets. These sedimentary structures were associated with an ichnological assemblage indicative of marine-influenced and brackish water, best represented by Ophiomorpha, Planolites-Palaeophycus-Thalassinoides and Thallassinoides-Planolites-Palaeophycus ichnofabrics. Sedimentation occurred in environments consisting of estuarine channel, estuarine central basin, tidal inlet/tidal channel, tidal delta/washover, tidal flat/shoal and foreshore, which were related to an estuarine setting, at least in part of a wave-dominated type. Analysis of facies stratal patterns led to suggest that the estuarine deposits of the Paraíba Basin reflect a rise in relative sea level probably during the transgressive and/or highstand stage of a depositional sequence formed directly overlying Cretaceous rocks. This rise can be correlated with the worldwide early/mid Miocene marine transgression. However, while the eustatic sea level remained rising through the middle Miocene, the estuarine sedimentation in the study area was cut off, being replaced by a regional unconformity marked by lateritic paleosols. Thus, a relative sea-level fall is recorded in the Paraíba Basin while the eustatic sea level remained rising through the middle Miocene, before its fall in the Tortonian. It follows that other factors, such as tectonics, is proposed to explain the mid-Miocene fall in sea level along the Paraíba coast, while the eustatic sea level was rising.

Margin Architecture and Sediment Flux as Controls on Submarine Fan Development: Tectonic-Climate Interactions in the Gulf of Alaska

NASA Astrophysics Data System (ADS)

Gulick, S. P. S.; Montelli, A.; Swartz, J. M.; Morey, S.; Jaeger, J. M.; Mix, A. C.; Reece, R.; Somchat, K.; Wagner, P. F.; Worthington, L. L.

2015-12-01

The oblique collision of the Yakutat microplate into southeast Alaska generates the St. Elias Mountains, a coastal orogen with significant moisture from the Gulf of Alaska resulting in large, temperate glacial systems that expand to and eventually cross the continental shelf during glacial maxima. We present an overview of the evolution of sediment routing on this margin from integration of seismic images, updated age models and core-log-seismic correlations from IODP Expedition 341 drilling sites, and mapping efforts from shelf, slope, and fan. We focus on the three dominant glacial systems during the climatically important intensification of Northern Hemisphere glaciation at the Plio-Pleistocene transition and the further intensification of glaciation since the mid-Pleistocene transition. Along strike, sediment delivery to deepwater from the three glacial systems varied according to Pleistocene shelf accommodation space. The Alsek crossed a narrower shelf with a bedrock high near the shelf edge; the Malaspina-Hubbard system crossed an undeformed, ~1 km deep shelf; the Bering-Bagley system crossed a several km deep shelf deforming as an active fold and thrust belt. The Malaspina and Bering catchments exhibit high exhumation rates onshore due to the Yakutat collision and upon reaching the shelf edge these glaciers generate trough mouth fans (TMFs) on the adjacent continental slope but only after first filling the available accommodation with glacigenic sediment and lowering the slope gradient through progradation. The Alsek crosses the shelf earliest but never with sufficient sediment flux to generate a TMF. An east-west transition in adjacent deepwater submarine channels that feed and generate the Surveyor Fan suggests that shelf accommodation and sediment flux are primary controls on sediment routing from orogen to submarine fan. Both of these parameters are in turn a function of initial tectonic architecture and ongoing orogen dynamics.

The electrical power subsystem design for the high energy solar physics spacecraft concepts

NASA Technical Reports Server (NTRS)

Kulkarni, Milind

1993-01-01

This paper discusses the Electrical Power Subsystem (EPS) requirements, architecture, design description, performance analysis, and heritage of the components for two spacecraft concepts for the High Energy Solar Physics (HESP) Mission. It summarizes the mission requirements and the spacecraft subsystems and instrument power requirements, and it describes the EPS architecture for both options. A trade study performed on the selection of the solar cells - body mounted versus deployed panels - and the optimum number of panels is also presented. Solar cell manufacturing losses, array manufacturing losses, and the radiation and temperature effects on the GaAs/Ge and Si solar cells were considered part of the trade study and are included in this paper. Solar cell characteristics, cell circuit description, and the solar array area design are presented, as is battery sizing analysis performed based on the power requirements during launch and initial spacecraft operations. This paper discusses Earth occultation periods and the battery power requirements during this period as well as shunt control, battery conditioning, and bus regulation schemes. Design margins, redundancy philosophy, and predicted on-orbit battery and solar cell performance are summarized. Finally, the heritage of the components and technology risk assessment are provided.

Architectural features of the Kayenta formation (Lower Jurassic), Colorado Plateau, USA: relationship to salt tectonics in the Paradox Basin

NASA Astrophysics Data System (ADS)

Bromley, Michael H.

1991-09-01

Fluvial sandstones of the Kayenta Formation were analyzed using architectural element analysis. Paleocurrent trends, the distribution of lacustrine facies and local silcrete development indicate that synsedimentary movement of evaporites in the underlying Paradox Basin created an unstable basin floor beneath the Kayenta fluvial system. This instability resulted in deflection of fluvial axes, local basin development and local areas of interrupted fluvial deposition with eolian dunes. Paleocurrent trends in the Kayenta system reflect periodic interruptions of southwesterly flow. Salt migrating laterally out of a rim syncline into an adjacent salt anticline resulted in a rim syncline of slight topographic relief. The resulting basin was probably rapidly filled, allowing the resumption of southwesterly flow. Differential movement of salt (incipient solution collapse features (?)) resulted in the formation of small centripetal basins in which playa mudstones formed. A laterally extensive resistant ledge underlies a horizontal surface, suggestive of deflation to the water table of an exposed section of valley fill. A channel scour in the top of one of these surfaces has margins much steeper ( > 60°) than the angle of repose for unconsolidated sand. Early cementation of the exposed floodplain could account for this resistance.

Discussion on final rifting evolution and breakup : insights from the Mid Norwegian - North East Greenland rifted system

NASA Astrophysics Data System (ADS)

Peron-Pinvidic, Gwenn; Terje Osmundsen, Per

2016-04-01

In terms of rifted margin studies, the characteristics of the distal and outer domains are among the today's most debated questions. The architecture and composition of deep margins are rarely well constrained and hence little understood. Except from in a handful number of cases (eg. Iberia-Newfoundland, Southern Australia, Red Sea), basement samples are not available to decipher between the various interpretations allowed by geophysical models. No consensus has been reached on the basement composition, tectonic structures, sedimentary geometries or magmatic content. The result is that non-unique end-member interpretations and models are still proposed in the literature. So, although these domains mark the connection between continents and oceans, and thus correspond to unique stages in the Earth's lithospheric life cycle, their spatial and temporal evolution are still unresolved. The Norwegian-Greenland Sea rift system represents an exceptional laboratory to work on questions related to rifting, rifted margin formation and sedimentary basin evolution. It has been extensively studied for decades by both the academic and the industry communities. The proven and expected oil and gas potentials led to the methodical acquisition of world-class geophysical datasets, which permit the detailed research and thorough testing of concepts at local and regional scales. This contribution is issued from a three years project funded by ExxonMobil aiming at better understanding the crustal-scale nature and evolution of the Norwegian-Greenland Sea. The idea was to take advantage of the data availability on this specific rift system to investigate further the full crustal conjugate scale history of rifting, confronting the various available datasets. In this contribution, we will review the possible structural and sedimentary geometries of the distal margin, and their connection to the oceanic domain. We will discuss the definition of 'breakup' and introduce a first order conceptual model that proposes a combined influence of tectonic and magmatic processes on the outbuilding of the distal, outer and oceanic domains.

Crustal structure of the Gulf of Aden southern margin: Evidence from receiver functions on Socotra Island (Yemen)

NASA Astrophysics Data System (ADS)

Ahmed, Abdulhakim; Leroy, Sylvie; Keir, Derek; Korostelev, Félicie; Khanbari, Khaled; Rolandone, Frédérique; Stuart, Graham; Obrebski, Mathias

2014-12-01

Breakup of continents in magma-poor setting occurs primarily by faulting and plate thinning. Spatial and temporal variations in these processes can be influenced by the pre-rift basement structure as well as by early syn-rift segmentation of the rift. In order to better understand crustal deformation and influence of pre-rift architecture on breakup we use receiver functions from teleseismic recordings from Socotra which is part of the subaerial Oligo-Miocene age southern margin of the Gulf of Aden. We determine variations in crustal thickness and elastic properties, from which we interpret the degree of extension related thinning and crustal composition. Our computed receiver functions show an average crustal thickness of ~ 28 km for central Socotra, which decreases westward along the margin to an average of ~ 21 km. In addition, the crust thins with proximity to the continent-ocean transition to ~ 16 km in the northwest. Assuming an initial pre-rift crustal thickness of 35 km (undeformed Arabian plate), we estimate a stretching factor in the range of ~ 2.1-2.4 beneath Socotra. Our results show considerable differences between the crustal structure of Socotra's eastern and western sides on either side of the Hadibo transfer zone; the east displays a clear intracrustal conversion phase and thick crust when compared with the western part. The majority of measurements across Socotra show Vp/Vs ratios of between 1.70 and 1.77 and are broadly consistent with the Vp/Vs values expected from the granitic and carbonate rock type exposed at the surface. Our results strongly suggest that intrusion of mafic rock is absent or minimal, providing evidence that mechanical thinning accommodated the majority of crustal extension. From our observations we interpret that the western part of Socotra corresponds to the necking zone of a classic magma-poor continental margin, while the eastern part corresponds to the proximal domain.

Along-strike variations of structural styles in the imbricated Molasse of Salzburg and Upper Austria: a 3-D seismic perspective

NASA Astrophysics Data System (ADS)

Hinsch, Ralph; Linzer, Hans-Gert

2010-05-01

At the southern border of the Northern Alpine Foreland Basin syntectonic deposits (Molasse Sediments) are partly incorporated into Alpine contractional deformation. Along the alpine chain style and timing of this deformation varies significantly. In this study we use one of the largest European on-shore 3-D seismic datasets, spanning the Molasse basin of Upper Austria and Salzburg states, to investigate the along-strike structural architecture of the alpine deformation front. In the Austrian Part of the Molasse basin, foredeep sedimentation started in Upper-Eocene times (Wagner, 1996). The sediments cover the European margin, consisting of a crystalline basement covered by variously thick Mesozoic sediments (Nachtmann und Wagner, 1987). In Oligocene to Lower Miocene times, syntectonic foredeep sedimentation took place in a deep marine environment, comprising an axial channel system (Linzer 2001, DeRuig and Hubbard, 2006). Parts of these syntectonic sediments are subsequently affected by the advancing thrust wedge. Within the study area, three distinct fold-and-thrust belt segments of different structural architecture can be defined. 1) The Perwang Imbricates are a promontory mostly situated in Salzburg at the border to Germany. Complexly deformed small thrust sheets evolve above a detachment horizon situated in Late Cretaceous shaly marls in Oligocene times. Syntectonic piggy-back and thrust top basins evolve (Covault et al. 2008), which are partly affected by subsequent Miocene overthrusting. 2) The Regau Segment is the area west of the Perwang lobe. It is dominated by few number of thrust sheets in the Molasse sediments. Instead, over-thrusting by the alpine wedge (pre-deformed Flysch and Helvetic thrust sheets) dominates. 3) The Sierning Imbricates segment is located further to the east, at the border of Upper Austria to Lower Austria. The structural inventory of this thrust belt is comprises varying numbers of thrust sheets along strike (1-5), ramp-flat-ramp geometries, tear faults as well as belt-parallel strike-slip faults. The differences in structural style along strike are interpreted to be caused by pre-deformational conditions (sediment thickness and distribution of potential decollement horizons) and varying tectonic pulses. Covault, J.A., Hubbard, S.M., Graham, S.A., Hinsch, R. and Linzer, H., 2008, Turbidite-reservoir architecture in complex foredeep-margin and wedge-top depocenters, Tertiary Molasse foreland basin system, Austria, Marine and Petroleum Geology, V26/3, 379-396 De Ruig, M. J., and Hubbard, S. M., 2006. Seismic facies and reservoir characteristics of a deep marine channel belt in the Molasse foreland basin. AAPG Bulletin, v. 90, p. 735-752 Linzer, H.-G., 2001, Cyclic channel systems in the Molasse foreland basin of the Eastern Alps- the effects of Late Oligocene foreland thrusting and Early Miocene lateral escape. AAPG Bulletin, 85, 118. Nachtmann, W., Wagner, L., 1987.Mesozoic and Early Tertiary evolution of the Alpine Foreland in Upper Austria and Salzburg, Austria. Tectonophysics, 137, 61-76 Wagner, L. R., 1996. Stratigraphy and hydrocarbons in the Upper Austrian Molasse Foredeep (active margin). In:Wessely, G., Liebl, W. (Eds.), Oil and Gas in Alpidic Thrustbelts and Basins of Central and Eastern Europe. EAGE Special Pub. 5, pp. 217-235.

Giving perspective to cliff exposures with ground penetrating radar: Devonian lacustrine shore zone architecture

NASA Astrophysics Data System (ADS)

Andrews, Steven; Moreau, Julien; Archer, Stuart

2015-04-01

The orbitally-controlled cyclic lacustrine successions of the Middle Devonian in Northern Scotland contains repeated developments of shore zone sandstones. However, due to the cliff-forming nature of the succession and the attitude of the sections through these sandstones, interpretation of this facies has been problematic. To better understand the shore zone systems, we carried out very high resolution sedimentary logging and constructed photo-panels which were combined with high resolution GPR profiling (250 MHz). To ensure close ties between the sedimentary logs and the GPR data, the cliffs were accessed using rope access techniques while GPR grids were shot directly above. The profiles were shot mainly in the strike direction of what was thought to be the shore elongation every 5-10 m and every 20-30 m in the dip direction. Shore zone systems of 3 different sequences have been imaged for a total of 1155 m of GPR profile collected. This configuration has allowed 3D visualisation of the architecture of the shore zone systems and, in combination with detailed sedimentology, provided insights into the generation of the dynamic shore zone environments. The coastal cliffs of northern Scotland expose sedimentary cycles on average 16-m-thick which record deep lake, perennial lake and playa environments. The shore zone deposits reach 2 to 3.5 m in thickness. Loading and discrete channel forms are recognised in both the GPR data and sedimentary logs through the lower portion of the lake shore zone successions. Up-section the sandstone beds appear to become amalgamated forming subtle low angle accretionary bar complexes which although visible in outcrop, after careful investigation, can be fully visualised and examined in the GPR data. The 3D visualisation allowed mapping the architecture and distribution of the bars . The orientation of these features, recognised from the survey, is consistent with extensive palaeocurrent measurements from oscillation ripples. Further loaded sandstone beds and sand-filled shallow channel features overlie the bar forms. The channels are well imaged in the radargrams where their wider context can be gained. Through the combination of high resolution GPR data and detailed sedimentological analysis determination of the processes through which the previously enigmatic lake shore zone sandstones has been possible. The shore zone sandstones overlie playa facies which contain abundant desiccation horizons, reflecting the most arid phase in the climatically-controlled lacustrine cycle. As climatic conditions ameliorated the rejuvenation of fluvial systems resulted in the transport of sand out into the basin. Initial deposition was limited to intermittent events where sediment was laid down on a water saturated substrate. Some of these may have occurred subaqueously as small scale turbidity flows. High resolution fluctuations in lake level resulted in periodic short-lived reworking events along the lake margin which produced amalgamated sands, forming low relief bars. Shore zone reworking is likely to have occurred over a wide area as the lake margin migrated back and forth, and gradually transgressed. Continued transgression forced fluvial systems back towards the basin margin.

Testing Spatial Correlation of Subduction Interplate Coupling and Forearc Morpho-Tectonics

NASA Technical Reports Server (NTRS)

Goldfinger, Chris; Meigs, Andrew; Meigs, Andrew; Kaye, Grant D.; VanLaningham, Sam

2005-01-01

Subduction zones that are capable of generating great (Mw greater than 8) earthquakes appear to have a common assemblage of forearc morphologic elements. Although details vary, each have (from the trench landward), an accretionary prism, outer arc high, outer forearc basin, an inner forean: basin, and volcanic arc. This pattern is common in spite of great variation in forearc architecture. Because interseismic strain is known to be associated with a locked seismogenic plate interface, we infer that this common forearc morphology is related, in an unknown way, to the process of interseismic Strain accumulation and release in great earthquakes. To date, however, no clear relationship between the subduction process and the common elements of upper plate form has emerged. Whereas certain elements of the system, i.e. the outer arc high, are reasonably well- understood in a structural context, there is little understanding of the structural or topographic evolution of the other key elements like the inner arc and inner forearc basin, particularly with respect to the coupled zone of earthquake generation. This project developed a model of the seismologic, topographic, and uplift/denudation linkages between forearc topography and the subduction system by: 1) comparing geophysical, geodetic, and topographic data from subduction margins that generate large earthquakes; 2) using existing GPS, seismicity, and other data to model the relationship between seismic cycles involving a locked interface and upper-plate topographic development; and 3) using new GPS data and a range-scale topographic, uplift, and denudation analysis of the presently aseismic Cascadia margin to constrain topographic/plate coupling relationships at this poorly understood margin.

Experimental changes of the cleavage pattern in the eggs of a gall midge (Wachtliella persicariae L.) after local ultrasonic treatment.

PubMed

Wolf, Rainer

1972-12-01

To affirm the hypothesis that during the early cleavage inWachtliella persicariae L., central and marginal ooplasm do not only differ by their kinematic aspects (Wolf, 1969; Wolf and Krause, 1971) but also physiologically, the radial symmetry of the ooplasm has been destroyed experimentally. For this purpose a device has been developed permitting a local ultrasonic treatment of insect eggs limited to well defined regions of various sizes (Fig. 1). The changes in the egg architecture can be observed directly while the treatment is going on and their effects on embryogenesis are analyzed by time-lapse motion pictures.Cleavage nuclei which have been transferred prematurely to the egg surface during low-intensity ultrasonic radiation of the whole egg length (Fig. 2 a), move back into the central ooplasm after treatment; the marginal plasm becomes populated only later at the same time as in untreated eggs. Local high-intensity ultrasonic treatment, too (Fig. 2 c), obviously does not cause any damage to the nuclei, while the ooplasm within the treated area becomes completely mixed up. After exposure the untreated region may become partially coated by a sheath of mixed up ooplasm. The populating of the egg surface by the nuclei is restricted to those sites where the untreated marginal ooplasm remains at the surface. These are the only areas for the later formation of preblastoderm and blastoderm. For the normal distribution of the cleavage energides a certain ooplasmic component sensitive to ultrasonic treatment seems to be responsible, the ultrastructure of which will be subjected to further investigations.

Environmental margin and island evolution in Middle Eastern populations of the Egyptian fruit bat.

PubMed

Hulva, P; Marešová, T; Dundarova, H; Bilgin, R; Benda, P; Bartonička, T; Horáček, I

2012-12-01

Here, we present a study of the population genetic architecture and microevolution of the Egyptian fruit bat (Rousettus aegyptiacus) at the environmental margins in the Middle East using mitochondrial sequences and nuclear microsatellites. In contrast to the rather homogenous population structure typical of cave-dwelling bats in climax tropical ecosystems, a relatively pronounced isolation by distance and population diversification was observed. The evolution of this pattern could be ascribed to the complicated demographic history at higher latitudes related to the range margin fragmentation and complex geomorphology of the studied area. Lineages from East Africa and Arabia show divergent positions. Within the northwestern unit, the most marked pattern of the microsatellite data set is connected with insularity, as demonstrated by the separate status of populations from Saharan oases and Cyprus. These demes also exhibit a reduction in genetic variability, which is presumably connected with founder effects, drift and other potential factors related to island evolution as site-specific selection. Genetic clustering indicates a semipermeability of the desert barriers in the Sahara and Arabian Peninsula and a corridor role of the Nile Valley. The results emphasize the role of the island environment in restricting the gene flow in megabats, which is also corroborated by biogeographic patterns within the family, and suggests the possibility of nascent island speciation on Cyprus. Demographic analyses suggest that the colonization of the region was connected to the spread of agricultural plants; therefore, the peripatric processes described above might be because of or strengthened by anthropogenic changes in the environment. © 2012 Blackwell Publishing Ltd.

Tidal-bundle sequences in the Jordan Sandstone (Upper Cambrian), southeastern Minnesota, U.S.A.: Evidence for tides along inboard shorelines of the Sauk Epicontinental Sea

USGS Publications Warehouse

Tape, C.H.; Cowan, Clinton A.; Runkel, Anthony C.

2003-01-01

This study documents for the first time tidal bundling in a lower Paleozoic sheet sandstone from the cratonic interior of North America, providing insights into the hydrodynamics of ancient epicontinental seas. The Jordan Sandstone (Upper Cambrian) in the Upper Mississippi Valley contains large-scale planar tabular cross-sets with tidal-bundle sequences, which were analyzed in detail at an exceptional exposure. Tidal-bundle sequences (neap-spring-neap cycles) were delineated by foreset thickening-thinning patterns and composite shale drapes, the latter of which represent accumulations of mud during the neap tides of neap-spring-neap tidal cycles. Fourier analysis of the bundle thickness data from the 26 measurable bundle sequences revealed cycles ranging from 15 to 34 bundles per sequence, which suggests a semidiurnal or mixed tidal system along this part of the Late Cambrian shoreline. We extend the tidal interpretation to widespread occurrences of the same facies in outcrops of lesser quality, where the facies is recognizable but too few bundles are exposed for tidal cycles to be measured. By doing so, this study shows that tidally generated deposits have a significant geographic and temporal extent in Upper Cambrian strata of central mid-continent North America. The deposition and preservation of tidal facies was related to the intermittent development of shoreline embayments during transgressions. The tidally dominated deposits filled ravined topographies that were repeatedly developed on the updip parts of the shoreface. Resulting coastal geomorphologies, accompanied perhaps by larger-scale changes in basinal conditions and/or configuration, led to changes in depositional conditions from wave-dominated to tide-dominated. Outcrops of the Jordan Sandstone tidal facies in the Upper Mississippi Valley represent the farthest inboard recorded transmission of ocean-generated tides in the Laurentian epicontinental seas, demonstrating that tidal currents were significant agents in the transport of sand along the far cratonic interior shorelines of Cambrian North America. The results of this study improve the facies-level understanding of the genesis of sheet sandstones. Furthermore, tidalites documented here occur in a specific position within a sequence stratigraphic architecture for the Jordan Sandstone. This provides a framework to compare these ancient deposits and processes to younger (e.g., Carboniferous) epicontinental systems where stratal and sediment dynamics are better documented. ?? 2003, SEPM (Society for Sedimentary Geology).

Channel simulation to facilitate mobile-satellite communications research

NASA Technical Reports Server (NTRS)

Davarian, Faramaz

1987-01-01

The mobile-satellite-service channel simulator, which is a facility for an end-to-end hardware simulation of mobile satellite communications links is discussed. Propagation effects, Doppler, interference, band limiting, satellite nonlinearity, and thermal noise have been incorporated into the simulator. The propagation environment in which the simulator needs to operate and the architecture of the simulator are described. The simulator is composed of: a mobile/fixed transmitter, interference transmitters, a propagation path simulator, a spacecraft, and a fixed/mobile receiver. Data from application experiments conducted with the channel simulator are presented; the noise converison technique to evaluate interference effects, the error floor phenomenon of digital multipath fading links, and the fade margin associated with a noncoherent receiver are examined. Diagrams of the simulator are provided.

The Portland Basin: A (big) river runs through it

USGS Publications Warehouse

Evarts, Russell C.; O'Connor, Jim E.; Wells, Ray E.; Madin, Ian P.

2009-01-01

Metropolitan Portland, Oregon, USA, lies within a small Neogene to Holocene basin in the forearc of the Cascadia subduction system. Although the basin owes its existence and structural development to its convergent-margin tectonic setting, the stratigraphic architecture of basin-fill deposits chiefly reflects its physiographic position along the lower reaches of the continental-scale Columbia River system. As a result of this globally unique setting, the basin preserves a complex record of aggradation and incision in response to distant as well as local tectonic, volcanic, and climatic events. Voluminous flood basalts, continental and locally derived sediment and volcanic debris, and catastrophic flood deposits all accumulated in an area influenced by contemporaneous tectonic deformation and variations in regional and local base level.

Prognostic Significance of Percentage and Architectural Types of Contemporary Gleason Pattern 4 Prostate Cancer in Radical Prostatectomy.

PubMed

Choy, Bonnie; Pearce, Shane M; Anderson, Blake B; Shalhav, Arieh L; Zagaja, Gregory; Eggener, Scott E; Paner, Gladell P

2016-10-01

The International Society of Urological Pathology (ISUP) 2014 consensus meeting recommended a novel grade grouping for prostate cancer that included dividing Gleason score (GS) 7 into grade groups 2 (GS 3+4) and 3 (GS 4+3). This division of GS 7, essentially determined by the percent of Gleason pattern (GP) 4 (< or >50%), raises the question of whether a more exact quantification of the percent GP 4 within GS 7 will yield additional prognostic information. Modifications were also made by ISUP regarding the definition of GP 4, now including 4 main architectural types: cribriform, glomeruloid, poorly formed, and fused glands. This study was conducted to analyze the prognostic significance of the percent GP 4 and main architectural types of GP 4 according to the 2014 ISUP grading criteria in radical prostatectomies (RPs). The cohort included 585 RP cases of GS 6 (40.2%), 3+4 (49.0%), and 4+3 (10.8%) prostate cancers. Significantly different 5-year biochemical recurrence (BCR)-free survival rates were observed among GS 6 (99%, 95% confidence interval [CI]: 97%-100%), 3+4 (81%, 95% CI: 76%-86%), and 4+3 (60%, 95% CI: 45%-71%) cancers (P<0.01). Dividing the GP 4 percent into quartiles showed a 5-year BCR-free survival of 84% (95% CI: 78%-89%) for 1% to 20%, 74% (95% CI: 62%-83%) for 21% to 50%, 66% (95% CI: 50%-78%) for 51% to 70%, and 32% (95% CI: 9%-59%) for >70% (P<0.001). Among the GP 4 architectures, cribriform was the most prevalent (43.7%), and combination of architectures with cribriform present was more frequently observed in GS 4+3 (60.3%). Glomeruloid was mostly (67.1%) seen combined with other GP 4 architectures. Unlike the other GP 4 architectures, glomeruloid as the sole GP 4 was observed only as a secondary pattern (ie, 3+4). Among patients with GS 7 cancer, the presence of cribriform architecture was associated with decreased 5-year BCR-free survival when compared with GS 7 cancers without this architecture (68% vs. 85%, P<0.01), whereas the presence of glomeruloid architecture was associated with improved 5-year BCR-free survival when compared with GS 7 cancers without this architecture (87% vs. 75%, P=0.01). However, GS 7 disease having only the glomeruloid architecture had significantly lower 5-year BCR-free survival than GS 6 cancers (86% vs. 99%, P<0.01). Multivariable Cox proportional hazards regression model for factors associated with BCR among GS 7 cancers identified age (hazard ratio [HR] 0.95, P<0.01), preoperative prostate-specific antigen (HR 1.07, P<0.01), positive surgical margin (HR 2.70, P<0.01), percent of GP 4 (21% to 50% [HR 2.21], 51% to 70% [HR 2.59], >70% [HR 6.57], all P<0.01), presence of cribriform glands (HR 1.78, P=0.02), and presence of glomeruloid glands (HR 0.43, P=0.03) as independent predictors. In conclusion, our study shows that increments in percent of GP 4 correlate with increased risk for BCR supporting the ISUP recommendation of recording the percent of GP 4 in GS 7 prostate cancers at RP. However, additional larger studies are needed to establish the optimal interval for reporting percent GP 4 in GS 7 cancers. Among the GP 4 architectures, cribriform independently predicts BCR, whereas glomeruloid reduces the risk of BCR. Distinction should be made between cribriform and glomeruloid architectures, despite glomeruloid being considered as an early stage of cribriform, as cribriform confers a higher risk for poorer outcome.

Contrasting basin architecture and rifting style of the Vøring Basin, offshore mid-Norway and the Faroe-Shetland Basin, offshore United Kingdom

NASA Astrophysics Data System (ADS)

Schöpfer, Kateřina; Hinsch, Ralph

2017-04-01

The Vøring and the Faroe-Shetland basins are offshore deep sedimentary basins which are situated on the outer continental margin of the northeast Atlantic Ocean. Both basins are underlain by thinned continental crust whose structure is still debated. In particular the nature of the lower continental crust and the origin of high velocity bodies located at the base of the lower crust are a subject of discussion in recent literature. Regional interpretation of 2D and 3D seismic reflection data, combined with well data, suggest that both basins share several common features: (i) Pre-Cretaceous faults that are distributed across the entire basin width. (ii) Geometries of pre-Jurassic strata reflecting at least two extensional phases. (iii) Three common rift phases, Late Jurassic, Campanian-Maastrichtian and Palaeocene. (iv) Large pre-Cretaceous fault blocks that are buried by several kilometres of Cretaceous and Cenozoic strata. (iii). (v) Latest Cretaceous/Palaeocene inversion. (vi) Occurrence of partial mantle serpentinization during Early Cretaceous times, as proposed by other studies, seems improbable. The detailed analysis of the data, however, revealed significant differences between the two basins: (i) The Faroe-Shetland Basin was a fault-controlled basin during the Late Jurassic but also the Late Cretaceous extensional phase. In contrast, the Vøring Basin is dominated by the late Jurassic rifting and subsequent thermal subsidence. It exhibits only minor Late Cretaceous faults that are localised above intra-basinal and marginal highs. In addition, the Cretaceous strata in the Vøring Basin are folded. (ii) In the Vøring Basin, the locus of Late Cretaceous rifting shifted westwards, affecting mainly the western basin margin, whereas in the Faroe-Shetland Basin Late Cretaceous rifting was localised in the same area as the Late Jurassic phase, hence masking the original Jurassic geometries. (iii) Devono-Carboniferous and Aptian/Albian to Cenomanian rift phases are present in the Faroe-Shetland Basin, but are not recognisable in the Vøring Basin. (iv) Based on seismic data only, a Permian/Triassic rift phase can be suggested for the Vøring Basin, but the evidence for an equivalent rift phase in the Faroe-Shetland Basin is inconclusive. The present study demonstrates that basins developing above a complex mosaic of basement terrains accreted during orogenic phases can exhibit significant differences in their architecture. The origin of these differences may be considered to be a result of inherited pre-existing large-scale structures (e.g. pre-existing fault blocks) and/or a non-uniform crustal thickness prior to rifting.

Some aspects of the role of rift inheritance on Alpine-type orogens

NASA Astrophysics Data System (ADS)

Tugend, Julie; Manatschal, Gianreto; Mohn, Geoffroy; Chevrot, Sébastien

2017-04-01

Processes commonly recognized as fundamental for the formation of collisional orogens include oceanic subduction, arc-continent and continent-continent collision. As collisional belts result from the closure of oceanic basins and subsequent inversion of former rifted margins, their formation and evolution may also in theory be closely interlinked with the initial architecture of the former rifted margins. This assumption is indeed more likely to be applicable in the case of Alpine-type orogens, mainly controlled by mechanical processes and mostly devoid of arc-related magmatism. More and more studies from present-day magma-poor rifted margins illustrate the complex evolution of hyperextended domains (i.e. severely thinned continental crust (<10 km) and/or exhumed serpentinized mantle with relatively minor magmatic additions) between unequivocal continental and oceanic domains. In this contribution, we compare the deep structure of the Pyrenean and Alpine belts to discuss some aspects of the relative role of rift-inherited hyperextension and collisional processes in building Alpine-type orogens. The Pyrenees and Western to Central Alps respectively result from the inversion of a Late Jurassic to Mid Cretaceous and an Early to Middle Jurassic rift system eventually floored by hyperextended crust, exhumed mantle and/or proto-oceanic crust. In spite of uncertainties on the initial width of the hyperextended and proto-oceanic domains, the rift-related pre-collisional architecture of the Alps shows many similarities with that proposed for the Pyrenees. Remnants of these domains occur in the internal parts of both orogens, but they are largely affected by orogeny-related deformation and show a HP-LT to HT-MP metamorphic overprint in the Alps as a result of a polyphase deformation history. Yet, recent high-resolution tomographic images across the Pyrenees (PYROPE) and the Alps (CIFALPS) reveal a surprisingly comparable present-day overall crustal and lithospheric structure. Based on the comparison between the two orogens we discuss: (1) the nature and depth of decoupling levels inherited from hyperextension; (2) the implications for restorations and interpretations of orogenic roots (former hyperextended domains vs. lower crust only); and (3) the nature and major role of buttresses in controlling the final stage of collisional processes. Eventually, we discuss the variability of the role of rift-inheritance in building Alpine-type orogens. The Pyrenees seem to represent one extreme, where rift-inheritance is important at different stages of collisional processes. In contrast, in the Alps the role of rift-inheritance is subtler, likely because of its more complex and polyphase compressional deformation history.

Cryogenic Fluid Management Technology for Moon and Mars Missions

NASA Technical Reports Server (NTRS)

Doherty, Michael P.; Gaby, Joseph D.; Salerno, Louis J.; Sutherlin, Steven G.

2010-01-01

In support of the U.S. Space Exploration Policy, focused cryogenic fluid management technology efforts are underway within the National Aeronautics and Space Administration. Under the auspices of the Exploration Technology Development Program, cryogenic fluid management technology efforts are being conducted by the Cryogenic Fluid Management Project. Cryogenic Fluid Management Project objectives are to develop storage, transfer, and handling technologies for cryogens to support high performance demands of lunar, and ultimately, Mars missions in the application areas of propulsion, surface systems, and Earth-based ground operations. The targeted use of cryogens and cryogenic technologies for these application areas is anticipated to significantly reduce propellant launch mass and required on-orbit margins, to reduce and even eliminate storage tank boil-off losses for long term missions, to economize ground pad storage and transfer operations, and to expand operational and architectural operations at destination. This paper organizes Cryogenic Fluid Management Project technology efforts according to Exploration Architecture target areas, and discusses the scope of trade studies, analytical modeling, and test efforts presently underway, as well as future plans, to address those target areas. The target areas are: liquid methane/liquid oxygen for propelling the Altair Lander Ascent Stage, liquid hydrogen/liquid oxygen for propelling the Altair Lander Descent Stage and Ares V Earth Departure Stage, liquefaction, zero boil-off, and propellant scavenging for Lunar Surface Systems, cold helium and zero boil-off technologies for Earth-Based Ground Operations, and architecture definition studies for long term storage and on-orbit transfer and pressurization of LH2, cryogenic Mars landing and ascent vehicles, and cryogenic production via in situ resource utilization on Mars.

Root water uptake and lateral interactions among root systems in a temperate forest

NASA Astrophysics Data System (ADS)

Agee, E.; He, L.; Bisht, G.; Gough, C. M.; Couvreur, V.; Matheny, A. M.; Bohrer, G.; Ivanov, V. Y.

2016-12-01

A growing body of research has highlighted the importance of root architecture and hydraulic properties to the maintenance of the transpiration stream under water limitation and drought. Detailed studies of single plant systems have shown the ability of root systems to adjust zones of uptake due to the redistribution of local water potential gradients, thereby delaying the onset of stress under drying conditions. An open question is how lateral interactions and competition among neighboring plants impact individual and community resilience to water stress. While computational complexity has previously hindered the implementation of microscopic root system structure and function in larger scale hydrological models, newer hybrid approaches allow for the resolution of these properties at the plot scale. Using a modified version of the PFLOTRAN model, which represents the 3-D physics of variably saturated soil, we model root water uptake in a one-hectare temperate forest plot under natural and synthetic forcings. Two characteristic hydraulic architectures, tap roots and laterally sprawling roots, are implemented in an ensemble of simulations. Variations of root architecture, their hydraulic properties, and degree of system interactions produce variable local response to water limitation and provide insights on individual and community response to changing meteorological conditions. Results demonstrate the ability of interacting systems to shift areas of active uptake based on local gradients, allowing individuals to meet water demands despite competition from their peers. These results further illustrate how inter- and intra-species variations in root properties may influence not only individual response to water stress, but also help quantify the margins of resilience for forest ecosystems under changing climate.

Packing of muscles in the rabbit shank influences three-dimensional architecture of M. soleus.

PubMed

Wick, Carolin; Böl, Markus; Müller, Florian; Blickhan, Reinhard; Siebert, Tobias

2018-07-01

Isolated and packed muscles (e.g. in the calf) exhibit different three-dimensional muscle shapes. In packed muscles, cross-sections are more angular compared to the more elliptical ones in isolated muscles. As far as we know, it has not been examined yet, whether the shape of the muscle in its packed condition influences its internal arrangement of muscle fascicles and accordingly the contraction behavior in comparison to the isolated condition. To evaluate the impact of muscle packing, we examined the three-dimensional muscle architecture of isolated and packed rabbit M. soleus for different ankle angles (65°, 75°, 85°, 90°, and 95°) using manual digitization (MicroScribe ® MLX). In general, significantly increased values of pennation angle and fascicle curvature were found in packed compared to isolated M. soleus (except for fascicle curvature at 90° ankle angle). On average, fascicle length of isolated muscles exceeded fascicle lengths of packed muscles by 2.6%. Reduction of pennation angle in the packed condition had only marginal influence on force generation (about 1% of maximum isometric force) in longitudinal direction (along the line of action) although an increase of transversal force component (perpendicular to the line of action) of about 26% is expected. Results of this study provide initial evidence that muscle packing limits maximum muscle performance observed in isolated M. soleus. Besides an enhanced understanding of the impact of muscle packing on architectural parameters, the outcomes of this study are essential for realistic three-dimensional muscle modeling and model validation. Copyright © 2018 Elsevier Ltd. All rights reserved.

Potential and limits to unravel the genetic architecture and predict the variation of Fusarium head blight resistance in European winter wheat (Triticum aestivum L.).

PubMed

Jiang, Y; Zhao, Y; Rodemann, B; Plieske, J; Kollers, S; Korzun, V; Ebmeyer, E; Argillier, O; Hinze, M; Ling, J; Röder, M S; Ganal, M W; Mette, M F; Reif, J C

2015-03-01

Genome-wide mapping approaches in diverse populations are powerful tools to unravel the genetic architecture of complex traits. The main goals of our study were to investigate the potential and limits to unravel the genetic architecture and to identify the factors determining the accuracy of prediction of the genotypic variation of Fusarium head blight (FHB) resistance in wheat (Triticum aestivum L.) based on data collected with a diverse panel of 372 European varieties. The wheat lines were phenotyped in multi-location field trials for FHB resistance and genotyped with 782 simple sequence repeat (SSR) markers, and 9k and 90k single-nucleotide polymorphism (SNP) arrays. We applied genome-wide association mapping in combination with fivefold cross-validations and observed surprisingly high accuracies of prediction for marker-assisted selection based on the detected quantitative trait loci (QTLs). Using a random sample of markers not selected for marker-trait associations revealed only a slight decrease in prediction accuracy compared with marker-based selection exploiting the QTL information. The same picture was confirmed in a simulation study, suggesting that relatedness is a main driver of the accuracy of prediction in marker-assisted selection of FHB resistance. When the accuracy of prediction of three genomic selection models was contrasted for the three marker data sets, no significant differences in accuracies among marker platforms and genomic selection models were observed. Marker density impacted the accuracy of prediction only marginally. Consequently, genomic selection of FHB resistance can be implemented most cost-efficiently based on low- to medium-density SNP arrays.

The Eastern Sardinian Margin (Tyrrhenian Sea, Western Mediterranean) : a key area to study the rifting and post-breakup evolution of a back-arc passive continental margin

NASA Astrophysics Data System (ADS)

Gaullier, Virginie; Chanier, Frank; Vendeville, Bruno; Maillard, Agnès; Thinon, Isabelle; Graveleau, Fabien; Lofi, Johanna; Sage, Françoise

2016-04-01

The Eastern Sardinian passive continental margin formed during the opening of the Tyrrhenian Sea, which is a back-arc basin created by continental rifting and oceanic spreading related to the eastward migrating Apennine subduction system (middle Miocene to Pliocene). Up to now, rifting in this key area was considered to be pro parte coeval with the Messinian Salinity Crisis (MSC, 5.96-5.32 Ma). We use the MSC seismic markers and the deformation of viscous salt and its brittle overburden as proxies to better delineate the timing of rifting and post-rift reactivation, and especially to quantify vertical and horizontal movements. On this young, highly-segmented margin, the Messinian Erosion Surface and the Upper and Mobile Units are systematically associated, respectively, to basement highs and deeper basins, showing that a rifted deep-sea domain already existed by Messinian times, therefore a major pre-MSC rifting episode occurred across the entire domain. Data show that there are no signs of Messinian syn-rift sediments, hence no evidence for rifting after Late Tortonian times. Moreover, because salt tectonics creates fan-shaped geometries in sediments, syn-rift deposits have to be carefully re-examined to distinguish the effects of crustal tectonics (rifting) and salt tectonics. We also precise that rifting is clearly diachronous from the upper margin (East-Sardinia Basin) to the lower margin (Cornaglia Terrace) with two unconformities, attributed respectively to the necking and to the lithospheric breakup unconformities. The onshore part of the upper margin has been recently investigated in order to characterize the large crustal faults affecting the Mesozoic series (geometry, kinematics and chronology) and to decipher the role of the structural inheritance and of the early rifting. Seaward, we also try to constrain the architecture and timing of the continent-ocean transition, between the hyper-extended continental crust and the first oceanic crust. Widespread post-breakup deformation also occurred during the Pliocene. Some Pliocene vertical movements have been evidenced by discovering localized gravity gliding of the salt and its Late Messinian (UU) and Early Pliocene overburden. To the South, crustal-scale southward tilting triggered along-strike gravity gliding of salt and cover recorded by upslope extension and downslope shortening. To the North, East of the Baronie Ridge, there was some post-salt crustal activity along a narrow N-S basement trough, bounded by crustal faults. The salt geometry would suggest that nothing happened after Messinian times, but some structural features (confirmed by analogue modelling) show that basement fault slip was accommodated by lateral salt flow, which thinned upslope and thickened downslope, while the overlying sediments remained sub-horizontal. Along the inner domain of Eastern Sardinian margin, the post-rift deformation style greatly varies. Compressional structures (reverse faults and folds) are observed both onshore and offshore while post-rift extensional structures are mainly identified offshore. Such late deformation could be attributed to mechanisms acting alone or combined, such as : i. the reactivation of the margin, as already described for the Ligurian, Algerian or South-Balearic margins due to the Eurasian-African convergence ; 2. the Zanclean reflooding and the resulting water overload on the elastic lithosphere ; 3. an episodic mantle upwelling.

Syn- and post-rift anomalous vertical movements in the eastern Central Atlantic passive margin: a transect across the Moroccan passive continental margin.

NASA Astrophysics Data System (ADS)

Charton, Remi; Bertotti, Giovanni; Arantegui, Angel; Luber, Tim; Redfern, Jonathan

2017-04-01

Traditional models of passive margin evolution suggesting generalised regional subsidence with rates decreasing after the break-up have been questioned in the last decade by a number of detailed studies. The occurrence of episodic km-scale exhumation well within the post-rift stage, possibly associated with significant erosion, have been documented along the Atlantic continental margins. Despite the wide-spread and increasing body of evidence supporting post-rift exhumation, there is still limited understanding of the mechanism or scale of these phenomena. Most of these enigmatic vertical movements have been discovered using low-temperature geochronology and time-temperature modelling along strike of passive margins. As proposed in previous work, anomalous upward movements in the exhuming domain are coeval with higher-than-normal downward movements in the subsiding domain. These observations call for an integrated analysis of the entire source-to-sink system as a pre-requisite for a full understanding of the involved tectonics. We reconstruct the geological evolution of a 50km long transect across the Moroccan passive margin from the Western Anti-Atlas (Ifni area) to the offshore passive margin basin. Extending the presently available low-temperature geochronology database and using a new stratigraphic control of the Mesozoic sediments, we present a reconstruction of vertical movements in the area. Further, we integrate this with the analysis of an offshore seismic line and the pattern of vertical movements in the Anti-Atlas as documented in Gouiza et al. (2016). The results based on sampled rocks indicate exhumation by circa 6km after the Variscan orogeny until the Middle Jurassic. During the Late Jurassic to Early Cretaceous the region was subsequently buried by 1-2km, and later exhumed by 1-2km from late Early/Late Cretaceous onwards. From the Permian to present day, the Ifni region is the link between the generally exhuming Anti Atlas and continually subsiding offshore basins. Along strike, the rifted margin exhibits significant variability in the architecture of the Mesozoic deposits onshore and present day offshore shelf. North of the High Atlas, the ca. 2km thick Mesozoic succession is characterized by continuous sedimentation. South of the High Atlas the thickness increases to 6km in the offshore Tarfaya basin, where the Jurassic succession may be separated by a regional unconformity. Further south, close to the border with Mauritania, the Triassic to Jurassic succession is missing and the Cretaceous attains less than a kilometre of strata. In the Meseta and High Atlas, studies documented a similar kinematic Mesozoic evolution, whereas in the Anti-Atlas Gouiza et al. (2016) and this study document a different evolution. In addition, the kinematic evolution of the Reguibate domain to the south is also different from the other segments, showing post-Variscan exhumation with amplitudes lower than the ones observed in the Anti-Atlas. These observations highlight changes in the pattern of enigmatic movements along the same passive continental margin thereby showing that passive continental margins are more complex than expected only a few years ago. Gouiza, M., Charton, R., Bertotti, G., Andriessen, P. and Storms, J.E.A., 2016. Post-Variscan evolution of the Anti-Atlas belt of Morocco constrained from low-temperature geochronology: International Journal of Earth Sciences.

Species-Specific Effects on Throughfall Kinetic Energy in Subtropical Forest Plantations Are Related to Leaf Traits and Tree Architecture

PubMed Central

Bruelheide, Helge; Härdtle, Werner; Kröber, Wenzel; Li, Ying; von Oheimb, Goddert

2015-01-01

Soil erosion is a key threat to many ecosystems, especially in subtropical China where high erosion rates occur. While the mechanisms that induce soil erosion on agricultural land are well understood, soil erosion processes in forests have rarely been studied. Throughfall kinetic energy (TKE) is influenced in manifold ways and often determined by the tree’s leaf and architectural traits. We investigated the role of species identity in mono-specific stands on TKE by asking to what extent TKE is species-specific and which leaf and architectural traits account for variation in TKE. We measured TKE of 11 different tree species planted in monocultures in a biodiversity-ecosystem-functioning experiment in subtropical China, using sand-filled splash cups during five natural rainfall events in summer 2013. In addition, 14 leaf and tree architectural traits were measured and linked to TKE. Our results showed that TKE was highly species-specific. Highest TKE was found below Choerospondias axillaris and Sapindus saponaria, while Schima superba showed lowest TKE. These species-specific effects were mediated by leaf habit, leaf area (LA), leaf pinnation, leaf margin, stem diameter at ground level (GD), crown base height (CBH), tree height, number of branches and leaf area index (LAI) as biotic factors and throughfall as abiotic factor. Among these, leaf habit, tree height and LA showed the highest effect sizes on TKE and can be considered as major drivers of TKE. TKE was positively influenced by LA, GD, CBH, tree height, LAI, and throughfall amount while it was negatively influenced by the number of branches. TKE was lower in evergreen, simple leaved and dentate leaved than in deciduous, pinnated or entire leaved species. Our results clearly showed that soil erosion in forest plantations can be mitigated by the appropriate choice of tree species. PMID:26079260

Joint Polar Satellite System (JPSS) Common Ground System (CGS) Architecture Overview and Technical Performance Measures

NASA Astrophysics Data System (ADS)

Grant, K. D.; Johnson, B. R.; Miller, S. W.; Jamilkowski, M. L.

2014-12-01

The National Oceanic and Atmospheric Administration (NOAA) and National Aeronautics and Space Administration (NASA) are jointly acquiring the next-generation civilian weather and environmental satellite system: the Joint Polar Satellite System (JPSS). The Joint Polar Satellite System will replace the afternoon orbit component and ground processing system of the current Polar-orbiting Operational Environmental Satellites (POES) managed by NOAA. The JPSS satellites will carry a suite of sensors designed to collect meteorological, oceanographic, climatological and geophysical observations of the Earth. The ground processing system for JPSS is known as the JPSS Common Ground System (JPSS CGS). Developed and maintained by Raytheon Intelligence, Information and Services (IIS), the CGS is a multi-mission enterprise system serving NOAA, NASA and their national and international partners. The CGS provides a wide range of support to a number of missions. Originally designed to support S-NPP and JPSS, the CGS has demonstrated its scalability and flexibility to incorporate all of these other important missions efficiently and with minimal cost, schedule and risk, while strengthening global partnerships in weather and environmental monitoring. The CGS architecture will be upgraded to Block 2.0 in 2015 to satisfy several key objectives, including: "operationalizing" S-NPP, which had originally been intended as a risk reduction mission; leveraging lessons learned to date in multi-mission support; taking advantage of newer, more reliable and efficient technologies; and satisfying new requirements and constraints due to the continually evolving budgetary environment. To ensure the CGS meets these needs, we have developed 48 Technical Performance Measures (TPMs) across 9 categories: Data Availability, Data Latency, Operational Availability, Margin, Scalability, Situational Awareness, Transition (between environments and sites), WAN Efficiency, and Data Recovery Processing. This paper will provide an overview of the CGS Block 2.0 architecture, with particular focus on the 9 TPM categories listed above. We will describe how we ensure the deployed architecture meets these TPMs to satisfy our multi-mission objectives with the deployment of Block 2.0 in 2015.

Species-Specific Effects on Throughfall Kinetic Energy in Subtropical Forest Plantations Are Related to Leaf Traits and Tree Architecture.

PubMed

Goebes, Philipp; Bruelheide, Helge; Härdtle, Werner; Kröber, Wenzel; Kühn, Peter; Li, Ying; Seitz, Steffen; von Oheimb, Goddert; Scholten, Thomas

2015-01-01

Soil erosion is a key threat to many ecosystems, especially in subtropical China where high erosion rates occur. While the mechanisms that induce soil erosion on agricultural land are well understood, soil erosion processes in forests have rarely been studied. Throughfall kinetic energy (TKE) is influenced in manifold ways and often determined by the tree's leaf and architectural traits. We investigated the role of species identity in mono-specific stands on TKE by asking to what extent TKE is species-specific and which leaf and architectural traits account for variation in TKE. We measured TKE of 11 different tree species planted in monocultures in a biodiversity-ecosystem-functioning experiment in subtropical China, using sand-filled splash cups during five natural rainfall events in summer 2013. In addition, 14 leaf and tree architectural traits were measured and linked to TKE. Our results showed that TKE was highly species-specific. Highest TKE was found below Choerospondias axillaris and Sapindus saponaria, while Schima superba showed lowest TKE. These species-specific effects were mediated by leaf habit, leaf area (LA), leaf pinnation, leaf margin, stem diameter at ground level (GD), crown base height (CBH), tree height, number of branches and leaf area index (LAI) as biotic factors and throughfall as abiotic factor. Among these, leaf habit, tree height and LA showed the highest effect sizes on TKE and can be considered as major drivers of TKE. TKE was positively influenced by LA, GD, CBH, tree height, LAI, and throughfall amount while it was negatively influenced by the number of branches. TKE was lower in evergreen, simple leaved and dentate leaved than in deciduous, pinnated or entire leaved species. Our results clearly showed that soil erosion in forest plantations can be mitigated by the appropriate choice of tree species.

Soil architecture relationships with dynamic soil physical processes: a conceptual study using natural, artificial, and 3D-printed soil cores

NASA Astrophysics Data System (ADS)

Lamandé, Mathieu; Schjønning, Per; Dal Ferro, Nicola; Morari, Francesco

2017-04-01

Pore system architecture is a key feature for understanding physical, biological and chemical processes in soils. Development of visualisation technics, especially x-ray CT, during recent years has been useful in describing the complex relationships between soil architecture and soil functions. We believe that combining visualization with physical models is a step further towards a better understanding of these relationships. We conducted a concept study using natural, artificial and 3D-printed soil cores. Eight natural soil cores (100 cm3) were sampled in a cultivated stagnic Luvisol at two depths (topsoil and subsoil), representing contrasting soil pore systems. Cylinders (100 cm3) were produced from plastic or from autoclaved aerated concrete. Holes of diameters 1.5 and 3 mm were drilled in the cylinder direction for the plastic cylinder and for one of the AAC cylinders. All natural and artificial cores were scanned in a micro x-ray CT scanner at a resolution of 35 µm. The reconstructed image of each soil core was printed with 3D multijet printing technology at a resolution of 29 µm. In some reconstructed digital volumes of the natural soil cores, pores of different sizes (equivalent diameter of 35, 70, 100, and 200 µm) were removed before additional 3D printing. Effective air-filled porosity, Darcian air permeability, and oxygen diffusion were measured on all natural, artificial and printed cores. The comparison of the natural and the artificial cores emphasized the difference in pore architecture between topsoil (sponge like) and subsoil (dominated by large vertical macropores). This study showed the high potential of using printed soil cores for understanding soil pore functions. The results confirm the suitability of the Ball model partitioning the pore system into arterial, marginal and remote pores to describe effects of soil structure on gas transport.

Reproducibility of Direct Quantitative Measures of Cortical Bone Micro-architecture of the Distal Radius and Tibia by HR-pQCT

PubMed Central

Burghardt, Andrew J.; Buie, Helen R.; Laib, Andres; Majumdar, Sharmila; Boyd, Steven K.

2010-01-01

Quantitative cortical micro-architectural endpoints are important for understanding structure-function relations in the context of fracture risk and therapeutic efficacy. This technique study details new image-processing methods to automatically segment and directly quantify cortical density, geometry, and micro-architecture from HR-pQCT images of the distal radius and tibia. An automated segmentation technique was developed to identify the periosteal and endosteal margins of the distal radius and tibia, and detect intra-cortical pore space morphologically consistent with Haversian canals. The reproducibility of direct quantitative cortical bone indices based on this method was assessed in a pooled dataset of 56 subjects with two repeat acquisitions for each site. The in vivo precision error was characterized using root mean square coefficient of variation (RMSCV%) from which, the least significant change (LSC) was calculated. Bland-Altman plots were used to characterize bias in the precision estimates. The reproducibility of cortical density and cross-sectional area measures was high (RMSCV <1% and <1.5%, respectively) with good agreement between young and elder medians. The LSC for cortical porosity (Ct.Po) was somewhat smaller in the radius (0.58%) compared with the distal tibia (0.84%) and significantly different between young and elder medians in the distal tibia (LSC: 0.75% vs. 0.92%; p<0.001). The LSC for pore diameter and distribution (Po.Dm and Po.Dm.SD) ranged between 15 and 23μm. Bland-Altman analysis revealed moderate bias for integral measures of area and volume, but not density nor microarchitecture. This study indicates HR-pQCT measures of cortical bone density and architecture can be measured in vivo with high reproducibility and limited bias across a biologically relevant range of values. The results of this study provide informative data for the design of future clinical studies of bone quality. PMID:20561906

3D architecture of cyclic-step and antidune deposits in glacigenic subaqueous fan and delta settings: Integrating outcrop and ground-penetrating radar data

NASA Astrophysics Data System (ADS)

Lang, Jörg; Sievers, Julian; Loewer, Markus; Igel, Jan; Winsemann, Jutta

2017-12-01

Bedforms related to supercritical flows are increasingly recognised as important constituents of many depositional environments, but outcrop studies are commonly hampered by long bedform wavelengths and complex three-dimensional geometries. We combined outcrop-based facies analysis with ground-penetrating radar (GPR) surveys to analyse the 3D facies architecture of subaqueous ice-contact fan and glacifluvial delta deposits. The studied sedimentary systems were deposited at the margins of the Middle Pleistocene Scandinavian ice sheets in Northern Germany. Glacifluvial Gilbert-type deltas are characterised by steeply dipping foreset beds, comprising cyclic-step deposits, which alternate with antidune deposits. Deposits of cyclic steps consist of lenticular scours infilled by backset cross-stratified pebbly sand and gravel. The GPR sections show that the scour fills form trains along the delta foresets, which can locally be traced for up to 15 m. Perpendicular and oblique to palaeoflow direction, these deposits appear as troughs with concentric or low-angle cross-stratified infills. Downflow transitions from scour fills into sheet-like low-angle cross-stratified or sinusoidally stratified pebbly sand, deposited by antidunes, are common. Cyclic steps and antidunes were deposited by sustained and surge-type supercritical density flows, which were related to hyperpycnal flows, triggered by major meltwater discharge or slope-failure events. Subaqueous ice-contact fan deposits include deposits of progradational scour fills, isolated hydraulic jumps, antidunes and (humpback) dunes. The gravel-rich fan succession consists of vertical stacks of laterally amalgamated pseudo-sheets, indicating deposition by pulses of waning supercritical flows under high aggradation rates. The GPR sections reveal the large-scale architecture of the sand-rich fan succession, which is characterised by lobe elements with basal erosional surfaces associated with scours filled with backsets related to hydraulic jumps, passing upwards and downflow into deposits of antidunes and (humpback) dunes. The recurrent facies architecture of the lobe elements and their prograding and retrograding stacking pattern are interpreted as related to autogenic flow morphodynamics.

Facies architecture of a Triassic rift-related Silicic Volcano-Sedimentary succession in the Tethyan realm, Peonias subzone, Vardar (Axios) Zone, northern Greece; Regional implications

NASA Astrophysics Data System (ADS)

Asvesta, Argyro; Dimitriadis, Sarantis

2010-06-01

In northern Greece, along the western edge of the Paleozoic Vertiscos terrane (Serbomacedonian massif) and within the Peonias subzone - the eastern part of the Vardar (Axios) Zone - a Silicic Volcano-Sedimentary (SVS) succession of Permo(?)-Skythian to Mid Triassic age records the development of a faulted continental margin and the formation of rhyolitic volcanoes along a continental shelf fringed by neritic carbonate accumulations. It represents the early rifting extensional stages that eventually led to the opening of the main oceanic basin in the western part of the Vardar (Axios) Zone (the Almopias Oceanic Basin). Even though the SVS succession is deformed, altered, extensively silicified and metamorphosed in the low greenschist facies, primary textures, original contacts and facies relationships are recognized in some places allowing clues for the facies architecture and the depositional environment. Volcanic and sedimentary facies analysis has been carried out at Nea Santa and Kolchida rhyolitic volcanic centres. Pyroclastic facies, mostly composed of gas-supported lapilli tuffs and locally intercalated accretionary lapilli tuffs, built the early cones which were then overridden by rhyolitic aphyric and minor K-feldspar-phyric lava flows. The characteristics of facies, especially the presence of accretionary lapilli, imply subaerial to coastal emplacement at this early stage. The mature and final stages of volcanism are mostly represented by quartz-feldspar porphyry intrusions that probably occupied the vents. At Nea Santa area, the presence of resedimented hyaloclastite facies indicates subaqueous emplacement of rhyolitic lavas and/or lobes. Moreover, quartz-feldspar-phyric sills and a partly extrusive dome featuring peperites at their margins are inferred to have intruded unconsolidated, wet carbonate sediments of the overlying Triassic Neritic Carbonate Formation, in a shallow submarine environment. The dome had probably reached above wave-base as is indicated by the presence of reworked rhyolitic clasts in the younger mixed rhyolite-carbonate epiclastic sedimentary facies. This facies is interpreted as mass- and debris-flow of mixed provenance, deposited below wave-base. The facies architecture of the SVS succession records a change in volcanic activity from explosive to effusive and then to intrusive. The depositional environment changed from subaerial-coastal to shallow submarine as the silicic volcanism evolved and carbonate sedimentation was progressively taking over, probably compensating for the gradual subsidence of the corresponding basin. Silicic magmatism and carbonate sedimentation were contemporaneous and spatially related. The timing of the rifting, the continental crustal elements involved and the accompanying tectonic, magmatic and sedimentary processes are features of the spatially and temporally evolving western peri-Tethyan region.

Facies architecture and paleohydrology of a synrift succession in the Early Cretaceous Choyr Basin, southeastern Mongolia

USGS Publications Warehouse

Ito, M.; Matsukawa, M.; Saito, T.; Nichols, D.J.

2006-01-01

The Choyr Basin is one of several Early Cretaceous rift basins in southwestern Mongolia that developed in specific regions between north-south trending fold-and-thrust belts. The eastern margin of the basin is defined by high-angle normal and/or strike-slip faults that trend north-to-south and northeast-to-southwest and by the overall geometry of the basin, which is interpreted to be a half graben. The sedimentary succession of the Choyr Basin documents one of the various types of tectono-sedimentary processes that were active in the rift basins of East Asia during Early Cretaceous time. The sedimentary infill of the Choyr Basin is newly defined as the Khalzan Uul and Khuren Dukh formations based on detailed mapping of lateral and vertical variations in component lithofacies assemblages. These two formations are heterotopic deposits and constitute a third-order fluvio-lacustrine sequence that can be divided into transgressive and highstand systems tracts. The lower part of the transgressive systems tract (TST) is characterized by sandy alluvial-fan and braided-river systems on the hanging wall along the western basin margin, and by a gravelly alluvial-fan system on the footwall along the eastern basin margin. The alluvial-fan and braided-river deposits along the western basin margin are fossiliferous and are interpreted to have developed in association with a perennial fluvial system. In contrast, alluvial-fan deposits along the eastern basin margin do not contain any distinct faunas or floras and are interpreted to have been influenced by a high-discharge ephemeral fluvial system associated with fluctuations in wetting and drying paleohydrologic processes. The lower part of the TST deposit fines upward to siltstone-dominated flood-plain and ephemeral-lake deposits that constitute the upper part of the TST and the lower part of the highstand systems tract (HST). These mudstone deposits eventually reduced the topographic irregularities typical of the early stage of synrift basin development, with an associated decrease in topographic-slope gradients. Finally, a high-sinuosity meandering river system drained to the south during the late highstand stage in response to the northward migration of the depocenter. The upper HST deposits are also fossiliferous and are interpreted to have been influenced by a perennial fluvial system, although the average annual discharge of this system was probably less than 5 percent of that involved in the formation of the lower TST deposits along the western basin margin. ?? 2006 Elsevier Ltd. All rights reserved.

Glaciotectonic deformation and reinterpretation of the Worth Point stratigraphic sequence: Banks Island, NT, Canada

NASA Astrophysics Data System (ADS)

Vaughan, Jessica M.; England, John H.; Evans, David J. A.

2014-05-01

Hill-hole pairs, comprising an ice-pushed hill and associated source depression, cluster in a belt along the west coast of Banks Island, NT. Ongoing coastal erosion at Worth Point, southwest Banks Island, has exposed a section (6 km long and ˜30 m high) through an ice-pushed hill that was transported ˜ 2 km from a corresponding source depression to the southeast. The exposed stratigraphic sequence is polydeformed and comprises folded and faulted rafts of Early Cretaceous and Late Tertiary bedrock, a prominent organic raft, Quaternary glacial sediments, and buried glacial ice. Three distinct structural domains can be identified within the stratigraphic sequence that represent proximal to distal deformation in an ice-marginal setting. Complex thrust sequences, interfering fold-sets, brecciated bedrock and widespread shear structures superimposed on this ice-marginally deformed sequence record subsequent deformation in a subglacial shear zone. Analysis of cross-cutting relationships within the stratigraphic sequence combined with OSL dating indicate that the Worth Point hill-hole pair was deformed during two separate glaciotectonic events. Firstly, ice sheet advance constructed the hill-hole pair and glaciotectonized the strata ice-marginally, producing a proximal to distal deformation sequence. A glacioisostatically forced marine transgression resulted in extensive reworking of the strata and the deposition of a glaciomarine diamict. A readvance during this initial stage redeformed the strata in a subglacial shear zone, overprinting complex deformation structures and depositing a glaciotectonite ˜20 m thick. Outwash channels that incise the subglacially deformed strata record a deglacial marine regression, whereas aggradation of glaciofluvial sand and gravel infilling the channels record a subsequent marine transgression. Secondly, a later, largely non-erosive ice margin overrode Worth Point, deforming only the most surficial units in the section and depositing a capping till. The investigation of the Worth Point stratigraphic sequence provides the first detailed description of the internal architecture of a polydeformed hill-hole pair, and as such provides an insight into the formation and evolution of an enigmatic landform. Notably, the stratigraphic sequence documents ice-marginal and subglacial glaciotectonics in permafrost terrain, as well as regional glacial and relative sea level histories. The reinterpreted stratigraphy fundamentally rejects the long-established paleoenvironmental history of Worth Point that assumed a simple ‘layer-cake’ stratigraphy including the type-site for an organically rich, preglacial interval (Worth Point Fm).

The application of active-source seismic imaging techniques to transtensional problems the Walker Lane and Salton Trough

NASA Astrophysics Data System (ADS)

Kell, Anna Marie

The plate margin in the western United States is an active tectonic region that contains the integrated deformation between the North American and Pacific plates. Nearly focused plate motion between the North American and Pacific plates within the northern Gulf of California gives way north of the Salton Trough to more diffuse deformation. In particular a large fraction of the slip along the southernmost San Andreas fault ultimately bleeds eastward, including about 20% of the total plate motion budget that finds its way through the transtensional Walker Lane Deformation Belt just east of the Sierra Nevada mountain range. Fault-bounded ranges combined with intervening low-lying basins characterize this region; the down-dropped features are often filled with water, which present opportunities for seismic imaging at unprecedented scales. Here I present active-source seismic imaging from the Salton Sea and Walker Lane Deformation Belt, including both marine applications in lakes and shallow seas, and more conventional land-based techniques along the Carson range front. The complex fault network beneath the Salton Trough in eastern California is the on-land continuation of the Gulf of California rift system, where North American-Pacific plate motion is accommodated by a series of long transform faults, separated by small pull-apart, transtensional basins; the right-lateral San Andreas fault bounds this system to the north where it carries, on average, about 50% of total plate motion. The Salton Sea resides within the most youthful and northerly "spreading center" in this several thousand-kilometer-long rift system. The Sea provides an ideal environment for the use of high-data-density marine seismic techniques. Two active-source seismic campaigns in 2010 and 2011 show progression of the development of the Salton pull-apart sub-basin and the northerly propagation of the Imperial-San Andreas system through time at varying resolutions. High fidelity seismic imagery documents the timing of strain transfer from the Imperial fault onto the San Andreas fault through the application of sequence stratigraphy. Evidence shows that the formation of the Salton and Mesquite sub-basins and the associated change of strain partitioning occurred within the last 20-40 k.y., essentially modifying a broader zone of transtension bounding the Imperial and San Andreas faults into two smaller zones of focused extension. The north-central Walker Lane contains a diffuse network of both strike-slip and normal faults, with some degree of strain partitioning characterized by normal faulting to the west along the eastern edge of the Sierra Nevada mountain range, and strike-slip faults to the east that define a diffuse boundary against the Basin and Range proper. A seismic study across the Mount Rose fault zone, bounding the Carson Range near Reno, Nevada, was carried out to investigate slip across a potential low-angle normal fault. A hammer seismic reflection and refraction profile combined with airborne LiDAR (light detection and ranging) imagery highlights fault scarp modification through minor slumping/landslides, providing a better understanding of the nature of slip on this fault. The northeastern margin of the Walker Lane is a region where both "Basin and Range" style normal faults and dextral strike-slip faults contribute to the northward propagation of the Walker Lane (essentially parallel to an equivalent northward propagation of the Mendocino triple junction). Near this intersection lies Pyramid Lake, bounded to the southwest by the dextral Pyramid Lake fault and to the northeast by the normal Lake Range fault. A high-resolution (sub-meter) seismic CHIRP survey collected in 2010 shows intriguing relationships into fault architecture beneath Pyramid Lake. Over 500 line-km of seismic data reveal a polarity flip in basin structure as down-to-the-east motion at the northern end of the Pyramid Lake fault rapidly gives way to down-to-the-west normal motion along the Lake Range fault. Alternating patterns of asymmetric and symmetric stratal patterns west of the Lake Range fault provides some evidence for segmentation of total slip along this large normal fault. Using dated sediment cores, slip rate for the Lake Range fault was found to be approximately 1 mm/yr during the Holocene. A complex zone of transtenstion was also observed in seismic CHIRP data in the northwest quadrant of the lake, where short, discontinuous faults hint at the development of a nascent shear zone trending to the northwest. (Abstract shortened by UMI.)

Ice-sheet dynamics through the Quaternary on the mid-Norwegian continental margin inferred from 3D seismic data.

PubMed

Montelli, A; Dowdeswell, J A; Ottesen, D; Johansen, S E

2017-02-01

Reconstructing the evolution of ice sheets is critical to our understanding of the global environmental system, but most detailed palaeo-glaciological reconstructions have hitherto focused on the very recent history of ice sheets. Here, we present a three-dimensional (3D) reconstruction of the changing nature of ice-sheet derived sedimentary architecture through the Quaternary Ice Age of almost 3 Ma. An extensive geophysical record documents a marine-terminating, calving Fennoscandian Ice Sheet (FIS) margin present periodically on the mid-Norwegian shelf since the beginning of the Quaternary. Spatial and temporal variability of the FIS is illustrated by the gradual development of fast-flowing ice streams and associated intensification of focused glacial erosion and sedimentation since that time. Buried subglacial landforms reveal a complex and dynamic ice sheet, with converging palaeo-ice streams and several flow-switching events that may reflect major changes in topography and basal thermal regime. Lack of major subglacial meltwater channels suggests a largely distributed drainage system beneath the marine-terminating part of the FIS. This palaeo-environmental examination of the FIS provides a useful framework for ice-sheet modelling and shows that fragmentary preservation of buried surfaces and variability of ice-sheet dynamics should be taken into account when reconstructing glacial history from spatially limited datasets.

A High-Fidelity Simulation of a Generic Commercial Aircraft Engine and Controller

NASA Technical Reports Server (NTRS)

May, Ryan D.; Csank, Jeffrey; Lavelle, Thomas M.; Litt, Jonathan S.; Guo, Ten-Huei

2010-01-01

A new high-fidelity simulation of a generic 40,000 lb thrust class commercial turbofan engine with a representative controller, known as CMAPSS40k, has been developed. Based on dynamic flight test data of a highly instrumented engine and previous engine simulations developed at NASA Glenn Research Center, this non-proprietary simulation was created especially for use in the development of new engine control strategies. C-MAPSS40k is a highly detailed, component-level engine model written in MATLAB/Simulink (The MathWorks, Inc.). Because the model is built in Simulink, users have the ability to use any of the MATLAB tools for analysis and control system design. The engine components are modeled in C-code, which is then compiled to allow faster-than-real-time execution. The engine controller is based on common industry architecture and techniques to produce realistic closed-loop transient responses while ensuring that no safety or operability limits are violated. A significant feature not found in other non-proprietary models is the inclusion of transient stall margin debits. These debits provide an accurate accounting of the compressor surge margin, which is critical in the design of an engine controller. This paper discusses the development, characteristics, and capabilities of the C-MAPSS40k simulation

Mars Sample Return mission utilizing in-situ propellant production

NASA Technical Reports Server (NTRS)

Zubrin, Robert; Price, Steve

1995-01-01

This report presents the results of a study examining the potential of in-situ propellant production (ISPP) on Mars to aid in achieving a low cost Mars Sample Return (MSR) mission. Two versions of such a mission were examined: a baseline version employing a dual string spacecraft, and a light weight version employing single string architecture with selective redundancy. Both systems employed light weight avionics currently being developed by Lockheed Martin, Jet Propulsion Lab and elsewhere in the aerospace community, both used a new concept for a simple, light weight parachuteless sample return capsule, both used a slightly modified version of the Mars Surveyor lander currently under development at Lockheed Martin for flight in 1998, and both used a combination of the Sabatier-electrolysis and reverse water gas shift ISPP systems to produce methane/oxygen propellant on Mars by combining a small quantity of imported hydrogen with the Martian CO2 atmosphere. It was found that the baseline mission could be launched on a Delta 7925 and return a 0.5 kg sample with 82 percent mission launch margin;over and beyond subsystem allocated contingency masses . The lightweight version could be launched on a Mid-Lite vehicle and return a 0.25 kg sample with 11 percent launch margin, over and above subsystem contingency mass allocations.

High resolution microendoscopy with structured illumination and Lugol's iodine staining for evaluation of breast cancer architecture

NASA Astrophysics Data System (ADS)

Dobbs, Jessica; Kyrish, Matthew; Krishnamurthy, Savitri; Grant, Benjamin; Kuerer, Henry; Yang, Wei; Tkaczyk, Tomasz; Richards-Kortum, Rebecca

2016-03-01

Intraoperative margin assessment to evaluate resected tissue margins for neoplastic tissue is performed to prevent reoperations following breast-conserving surgery. High resolution microendoscopy (HRME) can rapidly acquire images of fresh tissue specimens, but is limited by low image contrast in tissues with high optical scattering. In this study we evaluated two techniques to reduce out-of-focus light: HRME image acquisition with structured illumination (SI-HRME) and topical application of Lugol's Iodine. Fresh breast tissue specimens from 19 patients were stained with proflavine alone or Lugol's Iodine and proflavine. Images of tissue specimens were acquired using a confocal microscope and an HRME system with and without structured illumination. Images were evaluated based on visual and quantitative assessment of image contrast. The highest mean contrast was measured in confocal images stained with proflavine. Contrast was significantly lower in HRME images stained with proflavine; however, incorporation of structured illumination significantly increased contrast in HRME images to levels comparable to that in confocal images. The addition of Lugol's Iodine did not increase mean contrast significantly for HRME or SI-HRME images. These findings suggest that structured illumination could potentially be used to increase contrast in HRME images of breast tissue for rapid image acquisition.

Study on the application of seismic sedimentology in a stratigraphic-lithologic reservoir in central Junggar Basin

NASA Astrophysics Data System (ADS)

Yu, Yixin; Xia, Zhongmou

2017-06-01

This paper discusses the research idea of description for stratigraphic-lithologic reservoir based on seismic sedimentology methods. The sandstone reservoir of Jurrassic XiShanyao Formation in Junggar Basin is studied according to the theory and approaches of seismic sedimentology. By making full use of borehole data, the technologies of layer correlation based on the stratigraphic sequence framework, the forward seismic modeling, the stratal slicing and lithologic inversion are applied. It describes the range of denudation line, the distribution characteristics of sedimentary facies of the strata, the vertical and horizontal distribution of sand bodies and the favourable oil-gas bearing prospective area. The results shows that study area are dominated braided delta deposition including underwater distributary channel and distributary bay microfacies, the nip-out lines of the formation are northeast to southwest from north to south, the second Middle Jurassic sand body is the most widely distributed one among three sand bodies, the prospective oil-gas bearing area located in the south part and around the YG2 well area. The study result is effective on the practice of exploration in study area.

Preliminary Geologic Map of the Little Piute Mountains, California; a Digital Database

USGS Publications Warehouse

Howard, Keith A.; Dennis, Michael L.; Karlstrom, Karl; Phelps, Geoffrey A.

1997-01-01

Introduction The Little Piute Mountains in the eastern Mojave Desert expose a series of folds and thrust faults involving metamorphosed Paleozoic strata (Miller and others, 1982; Stone and others, 1983). Detailed mapping of these structures was undertaken to help elucidate regional Mesozoic structural evolution. Earlier geologic maps were prepared by Cooksley (1960a,b,c,d, generalized by Bishop, 1964) and Stone and others (1983). Deformed and metamorphosed Paleozoic and Triassic rocks form a stratal succession that was originally deposited in shallow seas on the North American craton. Based on lithologic sequence the units are correlated with unmetamorphosed equivalents 200 km to the northeast in the Grand Canyon, Arizona, and 35-50 km to the west in the Marble, Ship, and Providence Mountains, California (Stone and others, 1983). The Paleozoic sequence rests nonconformably on a heterogeneous basement of polydeformed Early Proterozoic gneiss (Miller and others, 1982; Wooden and Miller, 1990). Triassic and older rocks were deformed, metamorphosed to staurolite or andalusite grade, and intruded concordantly at their base by Late Cretaceous granodiorite (Miller and others, 1982).

Preliminary Geologic Map of the the Little Piute Mountains, San Bernardino County, California

USGS Publications Warehouse

Howard, Keith A.; Dennis, Michael L.; Karlstrom, Karl E.; Phelps, Geoffrey A.

1995-01-01

Introduction The Little Piute Mountains in the eastern Mojave Desert expose a series of folds and thrust faults involving metamorphosed Paleozoic strata (Miller and others, 1982; Stone and others, 1983). Detailed mapping of these structures was undertaken to help elucidate regional Mesozoic structural evolution. Earlier geologic maps were prepared by Cooksley (1960a,b,c,d, generalized by Bishop, 1964) and Stone and others (1983). Deformed and metamorphosed Paleozoic and Triassic rocks form a stratal succession that was originally deposited in shallow seas on the North American craton. Based on lithologic sequence the units are correlated with unmetamorphosed equivalents 200 km to the northeast in the Grand Canyon, Arizona, and 35-50 km to the west in the Marble, Ship, and Providence Mountains, California (Stone and others, 1983). The Paleozoic sequence rests nonconformably on a heterogeneous basement of polydeformed Early Proterozoic gneiss (Miller and others, 1982; Wooden and Miller, 1990). Triassic and older rocks were deformed, metamorphosed to staurolite or andalusite grade, and intruded concordantly at their base by Late Cretaceous granodiorite (Miller and others, 1982).

Rotation, narrowing and preferential reactivation of brittle structures during oblique rifting

NASA Astrophysics Data System (ADS)

Huismans, R. S.; Duclaux, G.; May, D.

2017-12-01

Occurrence of multiple faults populations with contrasting orientations in oblique continental rifts and passive margins has long sparked debate about relative timing of deformation events and tectonic interpretations. Here, we use high-resolution three-dimensional thermo-mechanical numerical modeling to characterize the evolution of the structural style associated with moderately oblique rifting in the continental lithosphere. Automatic analysis of the distribution of active extensional shears at the surface of the model demonstrates a characteristic deformation sequence. We show that upon localization, Phase 1 wide oblique en-échelon grabens develop, limited by extensional shears oriented orthogonal to σ3. Subsequent widening of the grabens is accompanied by a progressive rotation of the Phase 1 extensional shears that become sub-orthogonal the plate motion direction. Phase 2 is marked by narrowing of active deformation resulting from thinning of the continental lithosphere and development of a second-generation of extensional shears. During Phase 2 deformation localizes both on plate motion direction-orthogonal structures that reactivate rotated Phase 1 shears, and on new oblique structures orthogonal to σ3. Finally, Phase 3 consists in the oblique rupture of the continental lithosphere and produces an oceanic domain where oblique ridge segments are linked with highly oblique accommodation zones. We conclude that while new structures form normal to σ3 in an oblique rift, progressive rotation and long-term reactivation of Phase 1 structures promotes orthorhombic fault systems, critical to accommodate upper crustal extension and control oblique passive margin architecture. The distribution, orientation, and evolution of frictional-plastic structures observed in our models is remarkably similar to documented fault populations in the Gulf of Aden conjugate passive margins, which developed in moderately oblique extensional settings.

Quaternary evolution of the Fennoscandian Ice Sheet from 3D seismic data

NASA Astrophysics Data System (ADS)

Montelli, A.; Dowdeswell, J. A.; Ottesen, D.; Johansen, S. E.

2016-12-01

The Quaternary seismic stratigraphy and architecture of the mid-Norwegian continental shelf and slope are investigated using extensive grids of marine 2D and 3D seismic reflection data that cover more than 100,000 km2 of the continental margin. At least 26 distinct regional palaeo-surfaces have been interpreted within the stratigraphy of the Quaternary Naust Formation on the mid-Norwegian margin. Multiple assemblages of buried glacigenic landforms are preserved within the Naust Formation across most of the study area, facilitating detailed palaeo-glaciological reconstructions. We document a marine-terminating, calving Fennoscandian Ice Sheet (FIS) margin present periodically on the Norwegian shelf since at least the beginning of the Quaternary. Elongate, streamlined landforms interpreted as mega-scale glacial lineations (MSGLs) have been found within the upper part of the Naust sequence N ( 1.9-1.6 Ma), sugesting the development of fast-flowing ice streams since that time. Shifts in the location of depocentres and direction of features indicative of fast ice-flow suggest that several reorganisations in the FIS drainage have occurred since 1.5 Ma. Subglacial landforms reveal a complex and dynamic ice sheet, with converging palaeo-ice streams and several flow-switching events that may reflect major changes in topography and internal ice-sheet structure. Lack of subglacial meltwater channels suggests a largely distributed, low-volume meltwater system that drained the FIS through permeable subglacial till without leaving much erosional evidence. This regional palaeo-environmental examination of the FIS provides a useful framework for ice-sheet modelling and shows that fragmentary preservation of buried surfaces and variability of ice-sheet dynamics should be taken into account when reconstructing glacial history from spatially limited datasets.

Contrasting fluvial styles across the mid-Pleistocene climate transition in the northern shelf of the South China Sea: Evidence from 3D seismic data

NASA Astrophysics Data System (ADS)

Zhuo, Haiteng; Wang, Yingmin; Shi, Hesheng; He, Min; Chen, Weitao; Li, Hua; Wang, Ying; Yan, Weiyao

2015-12-01

Multiple successions of buried fluvial channel systems were identified in the Quaternary section of the mid-shelf region of the northern South China Sea, providing a new case study for understanding the interplay between sea level variations and climate change. Using three commercial 3D seismic surveys, accompanied by several 2D lines and a few shallow boreholes, the sequence stratigraphy, seismic geomorphology and stratal architecture of these fluvial channels were carefully investigated. Based on their origin, dimensions, planform geometries and infill architectures, six classes of channel systems, from Class 1 to Class 6, were recognized within five sequences of Quaternary section (SQ1 to SQ5). Three types of fluvial systems among them are incised in their nature, including the trunk incised valleys (Class 1), medium incised valleys (Class 2) and incised tributaries (Class 3). The other three types are unincised, which comprise the trunk channels (Class 4), lateral migrating channels (Class 5) and the stable channels (Class 6). The trunk channels and/or the major valleys that contain braided channels at their base are hypothesized to be a product of deposition from the "big rivers" that have puzzled the sedimentologists for the last decade, providing evidence for the existence of such rivers in the ancient record. Absolute age dates from a few shallow boreholes indicate that the landscapes that were associated with these fluvial systems changed significantly near the completion of the mid-Pleistocene climate transition (MPT), which approximately corresponds to horizon SB2 with an age of ∼0.6 Ma BP. Below SB2, the Early Pleistocene sequence (SQ1) is dominated by a range of different types of unincised fluvial systems. Evidence of incised valleys is absent in SQ1. In contrast, extensive fluvial incision occurred in the successions above horizon SB2 (within SQ2-SQ5). Although recent studies call for increased incision being a product of climate-controlled increase in river discharge, the down-dip location of our study area suggests that relative sea level change was the most important control of the evolution of fluvial systems. However, it is acknowledged that climate change was also important through its role in regulating glacio-eustasy. We speculate that the small amplitude and periodicity of sea level cycles before and during the MPT were not sufficient to fully expose the shelf and cause extensive fluvial incisions. Completion of the MPT as well as the onset of 100 ky climate cycles at ∼0.6 Ma, during which the duration of cycles and magnitude of sea level change both increased, are considered to be triggering event for extensive development of incised fluvial systems. In addition to the eustatically driven causes of enhanced incision, the intensification of the East Asia monsoon at 0.9 Ma and 0.6 Ma driven by the episodic uplift of the Tibetan Plateau may have also significantly enhanced the amplitude of sea level falls and thus the fluvial incisions of the northern shelf of the South China Sea.

Geomorphology, facies architecture, and high-resolution, non-marine sequence stratigraphy in avulsion deposits, Cumberland Marshes, Saskatchewan

USGS Publications Warehouse

Farrell, K.M.

2001-01-01

This paper demonstrates field relationships between landforms, facies, and high-resolution sequences in avulsion deposits. It defines the building blocks of a prograding avulsion sequence from a high-resolution sequence stratigraphy perspective, proposes concepts in non-marine sequence stratigraphy and flood basin evolution, and defines the continental equivalent to a parasequence. The geomorphic features investigated include a distributary channel and its levee, the Stage I crevasse splay of Smith et al. (Sedimentology, vol. 36 (1989) 1), and the local backswamp. Levees and splays have been poorly studied in the past, and three-dimensional (3D) studies are rare. In this study, stratigraphy is defined from the finest scale upward and facies are mapped in 3D. Genetically related successions are identified by defining a hierarchy of bounding surfaces. The genesis, architecture, geometry, and connectivity of facies are explored in 3D. The approach used here reveals that avulsion deposits are comparable in process, landform, facies, bounding surfaces, and scale to interdistributary bayfill, i.e. delta lobe deposits. Even a simple Stage I splay is a complex landform, composed of several geomorphic components, several facies and many depositional events. As in bayfill, an alluvial ridge forms as the feeder crevasse and its levees advance basinward through their own distributary mouth bar deposits to form a Stage I splay. This produces a shoestring-shaped concentration of disconnected sandbodies that is flanked by wings of heterolithic strata, that join beneath the terminal mouth bar. The proposed results challenge current paradigms. Defining a crevasse splay as a discrete sandbody potentially ignores 70% of the landform's volume. An individual sandbody is likely only a small part of a crevasse splay complex. The thickest sandbody is a terminal, channel associated feature, not a sheet that thins in the direction of propagation. The three stage model of splay evolution proposed by Smith et al. (Sedimentology, vol. 36 (1989) 1) is revised to include facies and geometries consistent with a bayfill model. By analogy with delta lobes, the avulsion sequence is a parasequence, provided that its definition is modified to be independent from sea level. In non-marine settings, facies contacts at the tops of regional peats, coals, and paleosols are analogous to marine flooding surfaces. A parasequence is redefined here as a relatively conformable succession of genetically related strata or landforms that is bounded by regional flooding surfaces or their correlative surfaces. This broader definition incorporates the concept of landscape evolution between regional flooding surfaces in a variety of depositional settings. With respect to landscape evolution, accommodation space has three spatial dimensions - vertical (x), lateral (y), and down-the-basin (z). A flood basin fills in as landforms vertically (x) and laterally accrete (y), and prograde down-the-basin (z). Vertical aggradation is limited by the elevation of maximum flood stage (local base level). Differential tectonism and geomorphology control the slope of the flood basin floor and the direction of landscape evolution. These processes produce parasequences that include inclined stratal surfaces and oriented, stacked macroforms (clinoforms) that show the magnitude and direction of landscape evolution. ?? 2001 Elsevier Science B.V. All rights reserved.

Geomorphology, facies architecture, and high-resolution, non-marine sequence stratigraphy in avulsion deposits, Cumberland Marshes, Saskatchewan

NASA Astrophysics Data System (ADS)

Farrell, K. M.

2001-02-01

This paper demonstrates field relationships between landforms, facies, and high-resolution sequences in avulsion deposits. It defines the building blocks of a prograding avulsion sequence from a high-resolution sequence stratigraphy perspective, proposes concepts in non-marine sequence stratigraphy and flood basin evolution, and defines the continental equivalent to a parasequence. The geomorphic features investigated include a distributary channel and its levee, the Stage I crevasse splay of Smith et al. (Sedimentology, vol. 36 (1989) 1), and the local backswamp. Levees and splays have been poorly studied in the past, and three-dimensional (3D) studies are rare. In this study, stratigraphy is defined from the finest scale upward and facies are mapped in 3D. Genetically related successions are identified by defining a hierarchy of bounding surfaces. The genesis, architecture, geometry, and connectivity of facies are explored in 3D. The approach used here reveals that avulsion deposits are comparable in process, landform, facies, bounding surfaces, and scale to interdistributary bayfill, i.e. delta lobe deposits. Even a simple Stage I splay is a complex landform, composed of several geomorphic components, several facies and many depositional events. As in bayfill, an alluvial ridge forms as the feeder crevasse and its levees advance basinward through their own distributary mouth bar deposits to form a Stage I splay. This produces a shoestring-shaped concentration of disconnected sandbodies that is flanked by wings of heterolithic strata, that join beneath the terminal mouth bar. The proposed results challenge current paradigms. Defining a crevasse splay as a discrete sandbody potentially ignores 70% of the landform's volume. An individual sandbody is likely only a small part of a crevasse splay complex. The thickest sandbody is a terminal, channel associated feature, not a sheet that thins in the direction of propagation. The three stage model of splay evolution proposed by Smith et al. (Sedimentology, vol. 36 (1989) 1) is revised to include facies and geometries consistent with a bayfill model. By analogy with delta lobes, the avulsion sequence is a parasequence, provided that its definition is modified to be independent from sea level. In non-marine settings, facies contacts at the tops of regional peats, coals, and paleosols are analogous to marine flooding surfaces. A parasequence is redefined here as a relatively conformable succession of genetically related strata or landforms that is bounded by regional flooding surfaces or their correlative surfaces. This broader definition incorporates the concept of landscape evolution between regional flooding surfaces in a variety of depositional settings. With respect to landscape evolution, accommodation space has three spatial dimensions — vertical ( x), lateral ( y), and down-the-basin ( z). A flood basin fills in as landforms vertically ( x) and laterally accrete ( y), and prograde down-the-basin ( z). Vertical aggradation is limited by the elevation of maximum flood stage (local base level). Differential tectonism and geomorphology control the slope of the flood basin floor and the direction of landscape evolution. These processes produce parasequences that include inclined stratal surfaces and oriented, stacked macroforms (clinoforms) that show the magnitude and direction of landscape evolution.

A comparison of hydraulic architecture in three similarly sized woody species differing in their maximum potential height.

PubMed

McCulloh, Katherine A; Johnson, Daniel M; Petitmermet, Joshua; McNellis, Brandon; Meinzer, Frederick C; Lachenbruch, Barbara

2015-07-01

The physiological mechanisms underlying the short maximum height of shrubs are not understood. One possible explanation is that differences in the hydraulic architecture of shrubs compared with co-occurring taller trees prevent the shrubs from growing taller. To explore this hypothesis, we examined various hydraulic parameters, including vessel lumen diameter, hydraulic conductivity and vulnerability to drought-induced embolism, of three co-occurring species that differed in their maximum potential height. We examined one species of shrub, one short-statured tree and one taller tree. We worked with individuals that were approximately the same age and height, which was near the maximum for the shrub species. A number of variables correlated with the maximum potential height of the species. For example, vessel diameter and vulnerability to embolism both increased while wood density declined with maximum potential height. The difference between the pressure causing 50% reduction in hydraulic conductance in the leaves and the midday leaf water potential (the leaf's hydraulic safety margin) was much larger in the shrub than the other two species. In general, trends were consistent with understory shrubs having a more conservative life history strategy than co-occurring taller species. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Ultra-low-power and robust digital-signal-processing hardware for implantable neural interface microsystems.

PubMed

Narasimhan, S; Chiel, H J; Bhunia, S

2011-04-01

Implantable microsystems for monitoring or manipulating brain activity typically require on-chip real-time processing of multichannel neural data using ultra low-power, miniaturized electronics. In this paper, we propose an integrated-circuit/architecture-level hardware design framework for neural signal processing that exploits the nature of the signal-processing algorithm. First, we consider different power reduction techniques and compare the energy efficiency between the ultra-low frequency subthreshold and conventional superthreshold design. We show that the superthreshold design operating at a much higher frequency can achieve comparable energy dissipation by taking advantage of extensive power gating. It also provides significantly higher robustness of operation and yield under large process variations. Next, we propose an architecture level preferential design approach for further energy reduction by isolating the critical computation blocks (with respect to the quality of the output signal) and assigning them higher delay margins compared to the noncritical ones. Possible delay failures under parameter variations are confined to the noncritical components, allowing graceful degradation in quality under voltage scaling. Simulation results using prerecorded neural data from the sea-slug (Aplysia californica) show that the application of the proposed design approach can lead to significant improvement in total energy, without compromising the output signal quality under process variations, compared to conventional design approaches.

The 3D fault and vein architecture of strike-slip releasing- and restraining bends: Evidence from volcanic-centre-relatedmineral deposits

USGS Publications Warehouse

Berger, B.R.; ,

2007-01-01

High-temperature, volcanic-centre-related hydrothermal systems involve large fluid-flow volumes and are observed to have high discharge rates in the order of 100-400 kg/s. The flows and discharge occur predominantly on networks of critically stressed fractures. The coupling of hydrothermal fluid flow with deformation produces the volumes of veins found in epithermal mineral deposits. Owing to this coupling, veins provide information on the fault-fracture architecture in existence at the time of mineralization. They therefore provide information on the nature of deformation within fault zones, and the relations between different fault sets. The Virginia City and Goldfield mining districts, Nevada, were localized in zones of strike-slip transtension in an Early to Mid-Miocene volcanic belt along the western margin of North America. The Camp Douglas mining area occurs within the same belt, but is localized in a zone of strike-slip transpression. The vein systems in these districts record the spatial evolution of strike-slip extensional and contractional stepovers, as well as geometry of faulting in and adjacent to points along strike-slip faults where displacement has been interrupted and transferred into releasing and restraining stepovers. ?? The Geological Society of London 2007.

The role of complement in the success of vaccination with conjugated vs. unconjugated polysaccharide antigen.

PubMed

Salehen, Nur'ain; Stover, Cordula

2008-01-24

The complement system, a well-characterised arm of the innate immune system, significantly influences the adaptive immune response via direct cell-cell interaction and maintenance of lymphoid organ architecture. Development of vaccines is a major advance in modern health care. In this review, we highlight the importance of the marginal zone in response to both, polysaccharide and conjugated vaccines, and discuss the relevance of complement herein, based on findings obtained from animal models with specific deletions of certain complement components and from vaccination reports of complement-deficient individuals. We conclude that both, intactness of the complement system and maturity of expression of its components, are relatively more important to aid in the immune response to polysaccharide vaccine than to conjugated vaccines.

Flying qualities and control system characteristics for superaugmented aircraft

NASA Technical Reports Server (NTRS)

Myers, T. T.; Mcruer, D. T.; Johnston, D. E.

1984-01-01

Aircraft-alone dynamics and superaugmented control system fundamental regulatory properties including stability and regulatory responses of the basic closed-loop systems; fundamental high and low frequency margins and governing factors; and sensitivity to aircraft and controller parameters are addressed. Alternative FCS mechanizations, and mechanizational side effects are also discussed. An overview of flying qualities considerations encompasses general pilot operations as a controller in unattended, intermittent and trim, and full-attention regulatory or command control; effective vehicle primary and secondary response properties to pilot inputs and disturbances; pilot control architectural possibilities; and comparison of superaugmented and conventional aircraft path responses for different forms of pilot control. Results of a simple experimental investigation into pilot dynamic behavior in attitude control of superaugmented aircraft configurations with high frequency time laps and time delays are presented.

Collision of the Tacheng block with the Mayile-Barleik-Tangbale accretionary complex in Western Junggar, NW China: Implication for Early-Middle Paleozoic architecture of the western Altaids

NASA Astrophysics Data System (ADS)

Zhang, Ji'en; Xiao, Wenjiao; Luo, Jun; Chen, Yichao; Windley, Brian F.; Song, Dongfang; Han, Chunming; Safonova, Inna

2018-06-01

Western Junggar in NW China, located to the southeast of the Boshchekul-Chingiz (BC) Range and to the north of the Chu-Balkhash-Yili microcontinent (CBY), played a key role in the architectural development of the western Altaids. However, the mutual tectonic relationships have been poorly constrained. In this paper, we present detailed mapping, field structural geology, and geochemical data from the Barleik-Mayile-Tangbale Complex (BMTC) in Western Junggar. The Complex is divisible into Zones I, II and III, which are mainly composed of Cambrian-Silurian rocks. Zone I contains pillow lava, siliceous shale, chert, coral-bearing limestone, sandstone and purple mudstone. Zone II consists of basaltic lava, siliceous shale, chert, sandstone and mudstone. Zone III is characterized by basalt, chert, sandstone and mudstone. These rocks represent imbricated ocean plate stratigraphy, which have been either tectonically juxtaposed by thrusting or form a mélange with a block-in-matrix structure. All these relationships suggest that the BMTC is an Early-Middle Paleozoic accretionary complex in the eastern extension of the BC Range. These Early Paleozoic oceanic rocks were thrust onto Silurian sediments forming imbricate thrust stacks that are unconformably overlain by Devonian limestone, conglomerate and sandstone containing fossils of brachiopoda, crinoidea, bryozoa, and plant stems and leaves. The tectonic vergence of overturned folds in cherts, drag-related curved cleavages and σ-type structures on the main thrust surface suggests top-to-the-NW transport. Moreover, the positive εNd(t) values of volcanic rocks from the Tacan-1 drill-core, and the positive εHf(t) values and post-Cambrian ages of detrital zircons from Silurian and Devonian strata to the south of the Tacheng block indicate that its basement is a depleted and juvenile lithosphere. And there was a radial outward transition from coral-bearing shallow marine (shelf) to deep ocean (pelagic) environments, and from OIB/E-MORB to N-MORB lava geochemistry away from the Tacheng block. Comparisons with published data suggest that these positive isotopic values, stratigraphic, structural and geochemical relationships can be best understood as an analogue of the relationships between the Ontong Java oceanic plateau and the Pacific oceanic crust. Therefore we propose that the basement of the Tacheng block was an Early Paleozoic oceanic plateau. The southern part of the Tacheng block was an accretionary complex and the northern part was an oceanic basin in the Early Paleozoic, the configuration of which is similar to that of the present Ontong Java oceanic plateau situated on the Pacific oceanic crust, and its accretion into the Solomon accretionary complex. The presence of Ordovician SSZ-type ophiolites, early Paleozoic blueschist and Silurian SSZ-type intrusions in the BMTC, and Early-Middle Paleozoic continental arc-related intrusive rocks in the northern margin of the CBY provide further corroboration of a former subduction zone between the southern West Junggar and the northern margin of the CBY. Furthermore, consideration of the fact that the Kokchetav-North Tianshan range was collaged to the southern margin of the CBY in the Ordovician-Devonian indicates that both ranges were amalgamated synchronously with the CBY constructing the Early-Middle Paleozoic architecture of western Altaids.

Magma-poor and magma-rich segments along the hyperextended, pre-Caledonian passive margin of Baltica

NASA Astrophysics Data System (ADS)

Andersen, Torgeir B.; Alsaif, Manar; Corfu, Fernando; Jakob, Johannes; Planke, Sverre; Tegner, Christian

2015-04-01

The Scandinavian Caledonides constitute a more than 1850 km long 'Himalayan-type' orogen, formed by collision between Baltica-Avalonia and Laurentia. Subduction-related magmatism in the Iapetus ended at ~430 Ma and continental convergence continued for ~30 Myr until ~400 Ma. The collision produced a thick orogenic wedge comprising the stacked remnants of the rifted to hyperextended passive Baltican margin (Andersen et al. 2012), as well as suspect, composite and outboard terranes, which were successively emplaced as large-scale nappe complexes onto Baltica during the Scandian collision (see Corfu et al. 2014 for a recent review). Large parts (~800 km) of the mountain-belt in central Scandinavia, particularly in the Särv and Seve Nappes and their counterparts in Troms, are characterised by spectacular dyke complexes emplaced into continental sediments (e.g. Svenningsen 2001, Hollocher et al. 2007). These constitute a magma-rich segment formed along the margin of Baltica or within hyperextended continental slivers outboard of Baltica. The intensity of the pre-Caledonian magmatism is comparable to that of the present NE-Atlantic and other volcanic passive margins. The volumes and available U-Pb ages of 610-597 Ma (Baird et al. 2014 and refs therein) suggest that the magmatism was short lived, intense and therefore compatible with a large igneous province (LIP). By analogy with present-day margins this LIP may have been associated with continental break-up and onset of sea-floor spreading. The remnants of the passive margin both north and south of the magma-rich segment have different architectures, and are almost devoid of rift/drift related magmatic rocks. Instead, these magma-poor segments are dominated by heterogeneous sediment-filled basins characterised by the abundant presence of solitary bodies of variably altered mantle peridotites, also commonly present as detrital serpentinites. These basins are interpreted to have formed by hyperextension. We suggest that the pre-Caledonian margin of Baltica underwent hyperextension until break-up, which was associated with emplacement of a LIP at ~600 Ma in the central segment. Andersen, T.B., Labrousse, L., Corfu, F. and Osmundsen, P.T., 2012: Evidence for hyperextension along the pre-Caledonian margin of Baltica. Jl. Geol. Soc. London, 601-612 Baird, G.B., Figg, SA. and Chamberlain, K.R., 2014: Intrusive age and geochemistry of the Kebne Dyke Complex in the Seve Nappe Complex, Kebnekaise Massif, arctic Sweden Caledonides, GFF, doi: 10.1080/11035897.2014.924553 Corfu, F., Andersen, T.B. and Gasser, D., 2014: The Scandinavian Caledonides: main features, conceptual advances and critical questions. Geol. Soc. London Spec. Publ. 390 doi:10.1144/SP390.25 Hollocher. K, Robinson, P., Walsh, E. and Terry M.P., 2007:The Neoproterozoic Ottfjellet dike swarm of the Middle Allochthon, traced geochemically into the hinterland, Western Gneiss Region, Norway. Am. Jl. Sci. 307, 901-953 Svenningsen, O., 2001: Onset of seafloor spreading in the Iapetus Ocean at 608Ma: precise age of the Sarek Dyke Swarm, northern Swedish Caledonides. Precambrian Res., 110, 241-254.

First direct observations linking confined supercritical turbidity currents to their depositional architecture and facies characteristics

NASA Astrophysics Data System (ADS)

Hage, S.; Cartigny, M.; Hughes Clarke, J. E.; Clare, M. A.; Sumner, E.; Hubbard, S. M.; Talling, P.; Lintern, G.; Stacey, C.; Vardy, M. E.; Hunt, J.; Vendettuoli, D.; Yokokawa, M.; Hizzett, J. L.; Vellinga, A. J.; Azpiroz, M.

2017-12-01

Turbidity currents transfer globally significant amounts of sediment via submarine channels from the continental margin to deep submarine fans. Submarine channel inception is thought to result from erosive, supercritical turbidity currents that are common in proximal settings of the marine realm. Recent monitoring of submarine processes have provided the first measurements of supercritical turbidity currents (Hughes Clarke, 2016), demonstrating that they drive the upstream migration of crescentic bedforms in confined submarine channels. Although upstream-migrating bedforms are common in confined channels across the world's oceans, there is considerable debate over the type of deposits that they produce. It is important to understand what types of deposit record these supercritical bedforms to potentially identify them from geological archives. For the first time, we combine direct measurements from supercritical field-scale turbidity currents with the facies and depositional architecture resulting from such flows. We show how the subsurface architecture evolves in a highly active channel at Squamish submarine delta, British Columbia, Canada. Repeated upstream migration of bedforms is found to create two main deposit geometries. First, regular back-stepping beds result from flow deceleration on the slightly-inclined sides of the bedforms. Second, lens-shaped scour fills composed of massive deposits result from erosion of the back-stepping beds by subsequent turbidity currents. We relate our findings to a range of ancient outcrop studies to demonstrate that supercritical flows are common in proximal settings through the geological record. This study provides the first direct observation-based model to identify confined supercritical turbidity currents and their associated upslope-migrating bedforms in the sedimentary record. This is important for correctly identifying the proximal sites of ancient submarine channels that served as past conduits for globally significant quantities of sediment to reach the deep sea.

Cis-Lunar Reusable In-Space Transportation Architecture for the Evolvable Mars Campaign

NASA Technical Reports Server (NTRS)

McVay, Eric S.; Jones, Christopher A.; Merrill, Raymond G.

2016-01-01

Human exploration missions to Mars or other destinations in the solar system require large quantities of propellant to enable the transportation of required elements from Earth's sphere of influence to Mars. Current and proposed launch vehicles are incapable of launching all of the requisite mass on a single vehicle; hence, multiple launches and in-space aggregation are required to perform a Mars mission. This study examines the potential of reusable chemical propulsion stages based in cis-lunar space to meet the transportation objectives of the Evolvable Mars Campaign and identifies cis-lunar propellant supply requirements. These stages could be supplied with fuel and oxidizer delivered to cis-lunar space, either launched from Earth or other inner solar system sources such as the Moon or near Earth asteroids. The effects of uncertainty in the model parameters are evaluated through sensitivity analysis of key parameters including the liquid propellant combination, inert mass fraction of the vehicle, change in velocity margin, and change in payload masses. The outcomes of this research include a description of the transportation elements, the architecture that they enable, and an option for a campaign that meets the objectives of the Evolvable Mars Campaign. This provides a more complete understanding of the propellant requirements, as a function of time, that must be delivered to cis-lunar space. Over the selected sensitivity ranges for the current payload and schedule requirements of the 2016 point of departure of the Evolvable Mars Campaign destination systems, the resulting propellant delivery quantities are between 34 and 61 tonnes per year of hydrogen and oxygen propellant, or between 53 and 76 tonnes per year of methane and oxygen propellant, or between 74 and 92 tonnes per year of hypergolic propellant. These estimates can guide future propellant manufacture and/or delivery architectural analysis.

Infection with Salmonella enterica Serovar Typhimurium Leads to Increased Proportions of F4/80+ Red Pulp Macrophages and Decreased Proportions of B and T Lymphocytes in the Spleen.

PubMed

Rosche, Kristin L; Aljasham, Alanoud T; Kipfer, James N; Piatkowski, Bryan T; Konjufca, Vjollca

2015-01-01

Infection of mice with Salmonella enterica serovar Typhimurium (Salmonella) causes systemic inflammatory disease and enlargement of the spleen (splenomegaly). Splenomegaly has been attributed to a general increase in the numbers of phagocytes, lymphocytes, as well as to the expansion of immature CD71+Ter119+ reticulocytes. The spleen is important for recycling senescent red blood cells (RBCs) and for the capture and eradication of blood-borne pathogens. Conservation of splenic tissue architecture, comprised of the white pulp (WP), marginal zone (MZ), and red pulp (RP) is essential for initiation of adaptive immune responses to captured pathogens. Using flow cytometry and four color immunofluorescence microscopy (IFM), we show that Salmonella-induced splenomegaly is characterized by drastic alterations of the splenic tissue architecture and cell population proportions, as well as in situ cell distributions. A major cause of splenomegaly appears to be the significant increase in immature RBC precursors and F4/80+ macrophages that are important for recycling of heme-associated iron. In contrast, the proportions of B220+, CD4+ and CD8+ lymphocytes, as well as MZ MOMA+ macrophages decrease significantly as infection progresses. Spleen tissue sections show visible tears and significantly altered tissue architecture with F4/80+ macrophages and RBCs expanding beyond the RP and taking over most of the spleen tissue. Additionally, F4/80+ macrophages actively phagocytose not only RBCs, but also lymphocytes, indicating that they may contribute to declining lymphocyte proportions during Salmonella infection. Understanding how these alterations of spleen microarchitecture impact the generation of adaptive immune responses to Salmonella has implications for understanding Salmonella pathogenesis and for the design of more effective Salmonella-based vaccines.

LEGOS: Object-based software components for mission-critical systems. Final report, June 1, 1995--December 31, 1997

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1998-08-01

An estimated 85% of the installed base of software is a custom application with a production quantity of one. In practice, almost 100% of military software systems are custom software. Paradoxically, the marginal costs of producing additional units are near zero. So why hasn`t the software market, a market with high design costs and low productions costs evolved like other similar custom widget industries, such as automobiles and hardware chips? The military software industry seems immune to market pressures that have motivated a multilevel supply chain structure in other widget industries: design cost recovery, improve quality through specialization, and enablemore » rapid assembly from purchased components. The primary goal of the ComponentWare Consortium (CWC) technology plan was to overcome barriers to building and deploying mission-critical information systems by using verified, reusable software components (Component Ware). The adoption of the ComponentWare infrastructure is predicated upon a critical mass of the leading platform vendors` inevitable adoption of adopting emerging, object-based, distributed computing frameworks--initially CORBA and COM/OLE. The long-range goal of this work is to build and deploy military systems from verified reusable architectures. The promise of component-based applications is to enable developers to snap together new applications by mixing and matching prefabricated software components. A key result of this effort is the concept of reusable software architectures. A second important contribution is the notion that a software architecture is something that can be captured in a formal language and reused across multiple applications. The formalization and reuse of software architectures provide major cost and schedule improvements. The Unified Modeling Language (UML) is fast becoming the industry standard for object-oriented analysis and design notation for object-based systems. However, the lack of a standard real-time distributed object operating system, lack of a standard Computer-Aided Software Environment (CASE) tool notation and lack of a standard CASE tool repository has limited the realization of component software. The approach to fulfilling this need is the software component factory innovation. The factory approach takes advantage of emerging standards such as UML, CORBA, Java and the Internet. The key technical innovation of the software component factory is the ability to assemble and test new system configurations as well as assemble new tools on demand from existing tools and architecture design repositories.« less

2 - 4 million years of sedimentary processes in the Labrador Sea: implication for North Atlantic stratigraphy

NASA Astrophysics Data System (ADS)

Mosher, D. C.; Saint-Ange, F.; Campbell, C.; Piper, D. J.

2012-12-01

Marine sedimentary records from the western North Atlantic show that a significant portion of sediment deposited since the Pliocene originated from the Canadian Shield. In the Labrador Sea, previous studies have shown that bottom currents .strongly influenced sedimentation during the Pliocene, while during the Quaternary, intensification of turbidity current flows related to meltwater events were a dominant factor in supplying sediment to the basin and in the development of the North Atlantic Mid-Ocean Channel (NAMOC). Despite understanding this general pattern of sediment flux, details regarding the transfer of sediment from the Labrador Shelf to deep water and from the Labrador Sea to the North Atlantic remain poorly understood. Our study focuses on sedimentary processes occurring along the Labrador margin since the Pliocene and their consequences on the margin architecture, connection to the NAMOC, and role in sediment flux from the Labrador basin to the Sohm Abyssal Plain. Piston core and high resolution seismic data reveal that during the Pliocene to mid Pleistocene, widespread slope failures led to mass transport deposition along the entire Labrador continental slope. After the mid Pleistocene, sedimentation along the margin was dominated by the combined effects of glaciation and active bottom currents. On the shelf, prograded sedimentary wedges filled troughs and agraded till sheets form intervening banks. On the slope, stacked glaciogenic fans developed seaward of transverse troughs between 400 and 2800 mbsl. On the lower slope, seismic data show thick sediment drifts capped by glacio-marine mud. This unit is draped by well stratified sediment and marks a switch from a contourite dominated regime to a turbidite dominated regime. This shift occurred around 0.5 - 0.8 ka and correlates to the intensification of glaciations. Late Pleistocene sediments on the upper slope consist of stratified sediments related to proglacial plume fall-out. Coarse grained sediments, other than ice rafted detritus, by-passed the upper and middle slope and were transported to the lower slope and deep ocean. Seismic profiles and multibeam data along the Labrador Slope show a complex network of channels, with wide flat-bottomed channels off Saglek Bank to narrow channels off Cartwright Bank. The channels merge around 3000 mbsl to form single wide (~20 km) channels that eventually intersect, or flow parallel to the NAMOC. Rapid development of the NAMOC from the mid to late Pleistocene affected depositional patterns for sediment sourced from the Labrador margin. Downslope-transported sediment from the Labrador margin mostly tends to fill the basin or feed into NAMOC through tributary systems, whereas sediments derived from Hudson Strait feed the NAMOC and eventually the Sohm Abyssal plain. Sediment transported southward by the Western Boundary Undercurrent and Labrador Current likely reflect input along the margin, from Hudson Strait to Orphan Basin. Turbidite spill-over deposits are observed onlapping the continental margin of Labrador and Newfoundland as far south as Newfoundland Ridge.

Phased occupation and retreat of the last British-Irish Ice Sheet in the southern North Sea; geomorphic and seismostratigraphic evidence of a dynamic ice lobe

NASA Astrophysics Data System (ADS)

Dove, Dayton; Evans, David J. A.; Lee, Jonathan R.; Roberts, David H.; Tappin, David R.; Mellett, Claire L.; Long, David; Callard, S. Louise

2017-05-01

Along the terrestrial margin of the southern North Sea, previous studies of the MIS 2 glaciation impacting eastern Britain have played a significant role in the development of principles relating to ice sheet dynamics (e.g. deformable beds), and the practice of reconstructing the style, timing, and spatial configuration of palaeo-ice sheets. These detailed terrestrially-based findings have however relied on observations made from only the outer edges of the former ice mass, as the North Sea Lobe (NSL) of the British-Irish Ice Sheet (BIIS) occupied an area that is now almost entirely submarine (c.21-15 ka). Compounded by the fact that marine-acquired data have been primarily of insufficient quality and density, the configuration and behaviour of the last BIIS in the southern North Sea remains surprisingly poorly constrained. This paper presents analysis of a new, integrated set of extensive seabed geomorphological and seismo-stratigraphic observations that both advances the principles developed previously onshore (e.g. multiple advance and retreat cycles), and provides a more detailed and accurate reconstruction of the BIIS at its southern-most extent in the North Sea. A new bathymetry compilation of the region reveals a series of broad sedimentary wedges and associated moraines that represent several terminal positions of the NSL. These former still-stand ice margins (1-4) are also found to relate to newly-identified architectural patterns (shallow stacked sedimentary wedges) in the region's seismic stratigraphy (previously mapped singularly as the Bolders Bank Formation). With ground-truthing constraint provided by sediment cores, these wedges are interpreted as sub-marginal till wedges, formed by complex subglacial accretionary processes that resulted in till thickening towards the former ice-sheet margins. The newly sub-divided shallow seismic stratigraphy (at least five units) also provides an indication of the relative event chronology of the NSL. While there is a general record of south-to-north retreat, seismic data also indicate episodes of ice-sheet re-advance suggestive of an oscillating margin (e.g. MIS 2 maximum not related to first incursion of ice into region). Demonstrating further landform interdependence, geographically-grouped sets of tunnel valleys are shown to be genetically related to these individual ice margins, providing clear insight into how meltwater drainage was organised at the evolving termini of this dynamic ice lobe. The newly reconstructed offshore ice margins are found to be well correlated with previously observed terrestrial limits in Lincolnshire and E. Yorkshire (Holderness) (e.g. MIS 2 maximum and Withernsea Till). This reconstruction will hopefully provide a useful framework for studies targeting the climatic, mass-balance, and external glaciological factors (i.e. Fennoscandian Ice Sheet) that influenced late-stage advance and deglaciation, important for accurately characterising both modern and palaeo-ice sheets.

What controls the reactivation or preservation of distal ocean-continent transitions: the example of the Err-Platta nappes, SE Switzerland

NASA Astrophysics Data System (ADS)

Epin, Marie-Eva; Manatschal, Gianreto; Amann, Méderic

2016-04-01

Studies in the Alps suggest that remnants of former Ocean-Continent Transitions (OCT) can be preserved, even in internal parts of mountain belts. In the past, these units have been erroneously interpreted as either mélanges related to subduction channels or polyphase penetrative Alpine deformation. Good examples have been described from the eclogitic Piemonte units in the Western Alps and in Corsica [Beltrando et al., 2014], leading to the question of what may have controlled the preservation of these structures. In our study we used the example of the Err-Platta nappes that expose remnants of the OCT of the former Alpine Tethys. The aim of our presentation is to: 1) define the characteristic features of an OCT across a fossil magma-poor rifted margin, and 2) show the control of the rift-inherited structures during the subsequent reactivation of the OCT. The characteristics of OCTs at magma-poor rifted margins are the juxtaposition of serpentinized mantle and crustal rocks and pre-rift sediments limited by brittle extensional detachment faults sealed by syn- and post-tectonic sediments locally associated with magmatic rocks. Thus, in contrast to proximal margins, where lithologies are continuous layer cakes, OCTs are characterized by non-continuous layers and isolated blocks. To identify extensional detachment faults in mountain belts, different fingerprints can be found such as fault rocks (gouges and cataclasites) that bear a mantle derived fluid signature, or the occurrence of massive breccias that contain clasts of the underlying exhumed basement. Using field examples, we will show how Alpine structures selectively reactivated some inherited structures of the OCT, while others remained undeformed and were preserved in the nappe stack. How far the complex morphology, fault architecture and rheology of OCTs control the reactivation is still unclear, however, it appears that serpentinization fronts, or former extensional detachment faults may have played a key role during the reactivation of the margin. This study allows us to reconsider "mélange zone" described in many collisional orogens, and to test, using diagnostic criteria and field observations, if they could represent former OCTs. Beltrando et al. Earth Science Reviews (2014)

Crustal structure of the Amundsen Sea Embayment, West Antarctica: Implications for its tectonic evolution from a geophysical dataset.

NASA Astrophysics Data System (ADS)

Kalberg, Thomas; Gohl, Karsten

2013-04-01

The Amundsen Sea Embayment of West Antarctica is a centrepiece in understanding the history of the New Zealand - Antarctica breakup. This region plays a key role in plate kinematic reconstruction of the southern Pacific from the collision of the Hikurangi Plateau with the Gondwana subduction margin to the evolution of the West Antarctic Rift System. During two RV Polarstern cruises in 2006 and 2010, a large geophysical dataset was collected consisting of seismic refraction and reflection profiles, shipborne gravity and helicopter magnetic measurements. The data provide constraints on the crustal architecture, the structural evolution and the tectonic block formation during and after the Cretaceous continental breakup. We present two continental rise-to-shelf P-wave velocity models which were derived from forward travel-time modelling of ocean bottom hydrophone recordings which provide an insight into the crustal and upper mantle architecture beneath the Amundsen Sea Embayment for the first time. The sedimentary sequences and the basement were constrained by seismic reflection data. A 2-D density-depth model supports and complements the P-wave modelling. Observed P-wave velocities show 10 to 14 km thick crust of the continental rise and up to 28 km thick crust beneath the middle and inner shelf. The crust of the continental rise is characterized by a small gradient in thickness. Including horst and graben structures this can be associated with wide-mode rifting. A high velocity zone with velocities ranging between 7.1 and 7.6 km/s indicate magmatic underplating of variable thickness along the entire transect. We classify this margin as one of volcanic type rather than magma poor because of the high-velocity zone and seaward dipping reflectors observed from the seismic reflection data. We discuss the possibility of a serpentinized upper mantle caused by seawater penetration at the Marie Byrd Seamounts. The crustal structure, distinct zones in potential field anomalies indicate several phases of fully developed and failed rift systems and a possible branch of the West Antarctic Rift System in the Amundsen Sea Embayment.

Stratigraphic response across a structurally dynamic shelf: The latest guadalupian composite sequence at Walnut Canyon, New Mexico, U.S.A

USGS Publications Warehouse

Rush, J.; Kerans, C.

2010-01-01

The uppermost Yates and Tansill formations (Late Permian), as exposed along Walnut Canyon in Carlsbad Caverns National Park, New Mexico, USA, provide a unique opportunity to document the depositional architecture of a progradational, oversteepened, and mechanically failure-prone carbonate platform. Detailed facies mapping permitted critical assessment of depositional processes operating along this structurally dynamic platform margin. At the shelf crest, thick (12 m), vertically stacked fenestral-pisolite-tepee complexes indicate a stable shoreline. Early lithification of sediments and extensive cementation fostered rapid vertical accretion and allowed the shelf crest to easily adjust to base-level oscillations by stepping landward, stepping seaward, or aggrading. This production imbalance-in combination with syndepositional brittle failure and down-to-the-basin tilting(< 5??)-generated 22 m of depositional relief as measured from nearly horizontal (< 2??) shelf-crest toplap to an outer-shelf downlap surface (< 1??). Mechanical failure of Capitan-equivalent back-reef strata is constrained by stratigraphic architecture, fracture properties, and a highly refined fusulinid biostratigraphic framework. Where fractures tip out, down-to-the-basin rotation is often observed with concurrent seaward thickening of overlying beds, indicating that such fractures functioned as a syndepositional hinge. A facies disjunction and horizontally juxtaposed fusulinid zonation were documented across an 80?? seaward-dipping dilational fracture filled with polymict breccia. An overlying damage zone consisting of spar-cemented fractures nested within silt-filled fractures illustrates periodic reactivation. Field relationships indicate that the dilational fracture approximates a paleoescarpment that resulted from catastrophic failure of the Capitan platform margin. Younger strata onlapped the paleoescarpment and gradually filled the reentrant. This mechanically compromised paleoescarpment was subsequently reactivated during the latest Guadalupian lowstand and was subaerially filled by siliciclastics and polymict breccia derived from the platform top. Results from Walnut Canyon indicate that shelf crest aggradation dominantly controlled the shelf-crest to outer-shelf profile, although this was temporarily modified by brittle failure and down-to-the-basin tilting, and mass wasting. Copyright ?? 2010, SEPM (Society for Sedimentary Geology).

The Ordovician Sebree Trough: An oceanic passage to the Midcontinent United States

USGS Publications Warehouse

Kolata, Dennis R.; Huff, W.D.; Bergstrom, Stig M.

2001-01-01

The Sebree Trough is a relatively narrow, shale-filled sedimentary feature extending for several hundred kilometers across the Middle and Late Ordovician carbonate platform of the Midcontinent United States. The dark graptolitic shales within the trough stand in contrast to the coeval bryozoan-brachiopod-echinodermrich limestones on the flanking platforms. We infer from regional stratal patterns, thickness and facies trends, and temporal relations established by biostratigraphy and K-bentonite stratigraphy that the Sebree Trough initially began to develop during late Turinian to early Chatfieldian time (Mohawkian Series) as a linear bathymetric depression situated over the failed late Precambrian-Early Cambrian Reelfoot Rift. Rising sea level and positioning of a subtropical convergence zone along the southern margin of Laurentia caused the rift depression to descend into cool, oxygen-poor, phosphate-rich oceanic waters that entered the southern reaches of the rift from the Iapetus Ocean. The trough apparently formed in a system of epicontinental estuarine circulation marked by a density-stratified water column. Trough formation was accompanied by cessation of carbonate sedimentation, deposition of graptolitic shales, development of hardground omission surfaces, substrate erosion, and local phosphogenesis. The carbonate platforms on either side of the trough are dominated by bryozoan-brachiopod-echinoderm grainstones and packstones that were deposited in zones of mixing where cool, nutrient-rich waters encountered warmer shelf waters. Concurrently, lime mudstone and wackestone were deposited shoreward (northern Illinois, Wisconsin, Iowa, Minnesota, Michigan) in warmer, more tropical shallow seas. Coeval upward growth of the flanking carbonate platforms sustained and enhanced development of the trough shale facies. Five widespread diachronous late Mohawkian and Cincinnatian omission surfaces are present in the carbonate facies of the Midcontinent. These surfaces include sub-Deicke K-bentonite, DSI; top of Black River Limestone, DS2; base and top of the Guttenberg Limestone Member of the Decorah Formation, DS3 and DS4; and top of the Trenton Limestone, DS5. Some of the surfaces correspond to previously described depositional sequence boundaries. All five surfaces, which embody deepening phases on top of high-stand-systems tracts, converge in the Sebree Trough, indicating that the trough was a long-lived feature and was the source of eutrophic waters that episodically spread across the adjacent platforms, terminating carbonate production. Late Turinian and early Chatfieldian incipient drowning episodes were followed by a final drowning event that began in the Sebree Trough during the late Chatfieldian (Climacograptus spiniferus Zone) and reached southernmost Minnesota and other regions far within the platform interior by Richmondian time (Amorphognathus ordovicicus Zone).

Crustal Structure, Seismic Anisotropy and Deformations of the Ediacaran/Cambrian of the Małopolska Block in SE Poland Based on Data from Two Seismic Wide-Angle Experiments

NASA Astrophysics Data System (ADS)

Środa, Piotr

2017-04-01

The area of SE Poland represents a complex contact of tectonic units of different consolidation age—from the Precambrian East European Craton, through Palaeozoic West European Platform (including Małopolska Block) to Cenozoic Carpathians and Carpathian Foredeep. In order to investigate the anisotropic properties of the upper crust of the Małopolska Block and their relation to tectonic evolution of the area, two seismic datasets were used: seismic wide-angle off-line recordings from POLCRUST-01 deep seismic reflection profile and recordings from active deep seismic experiment CELEBRATION 2000. During acquisition of deep reflection seismic profile POLCRUST-01 in 2010, a 35-km-long line of 14 recorders (PA-14), oriented perpendicularly to the profile, was deployed to record the refractions from the upper crust (Pg) at wide range of azimuths. These data were used for an analysis of the azimuthal anisotropy of the MB with the modified delay-time inversion method. The results of modelling of the off-line refractions from the MB suggest 6% HTI anisotropy of the Cambrian/Ediacaran basement, with 130º azimuth of the fast velocity axis and mean Vp of 4.9 km/s. To compare this result with previous, independent information about anisotropy at larger depth, a subset of previously modelled data from CELEBRATION 2000 experiment, recorded in the MB area, was also analysed by inversion. The recordings of Pg phase at up to 120 km offsets were analysed using anisotropic delay-time inversion, providing information down to 12 km depth. The CELEBRATION 2000 model shows 9% HTI anisotropy with 126º orientation of the fast axis. Thus, local-scale anisotropy of this part of MB confirms the large-scale anisotropy suggested by previous studies based on data from a broader area and larger depth interval. The azimuthal anisotropy (i.e. HTI symmetry of the medium) is interpreted as a result of strong compressional deformation during the accretion of terranes to the EEC margin, leading to tight (sub-vertical) folding and fracturing of intrinsically anisotropic metasediments forming the MB basement. Obtained anisotropy models are compared with data about stratal dips of the MB sequences and implications of assuming more realistic TTI model are discussed. Wide-angle recordings from off-line measurements along a reflection profile provided new information about seismic velocity and anisotropy, not available from standard near-vertical profiling, and contributed to more complete image of the upper crustal structure of Małopolska Block.

Motivation for DOC III: 64-bit digital optical computer

NASA Astrophysics Data System (ADS)

Guilfoyle, Peter S.

1991-09-01

OptiComp has focused on a digital optical logic family in order to capitalize on the inherent benefits of optical computing, which include (1) high FAN-IN and FAN-OUT, (2) low power consumption, (3) high noise margin, (4) high algorithmic efficiency using 'smart' interconnects, and (5) free-space leverage of gate interconnect bandwidth product. Other well-known secondary advantages of optical logic include zero capacitive loading of signals at a detector, zero cross-talk between signals, zero signal dispersion, and minimal clock skew (a few picoseconds or less in an imaging system). The primary focus of this paper is to demonstrate how each of the five advantages can be used to leverage other logic family performance such as GaAs; the secondary attributes are discussed only in the context of introducing the DOC III architecture.

Book Review: Book review

NASA Astrophysics Data System (ADS)

Xiao, Wenjiao

2016-06-01

This monograph book represents an important volume summarizing the present geological knowledge and understanding of the geodynamic evolution of large parts of the Central Asian Orogenic Belt (CAOB) or Altaids, which is one of the largest orogenic collages on Earth. The CAOB, like other major accretionary orogens, is a complex assembly of ancient microcontinents, arc terranes, accretionary wedges, fragments of oceanic volcanic islands (sea-mounts), oceanic plateaus, ophiolites, and shelf sediments from passive continental margins. The CAOB has caused much international attention due to its complicated architecture and considerably continental growth. However, after many years of investigations, some fundamental problems still remain controversial, such as the rate and volume of crustal growth, the origin of continental fragments, the detailed mechanism of accretion and collision, the role of terrane rotations during the orogeny, and the age and composition of the lower crust in Central Asia.

Overview of the randomized trials of radiotherapy in ductal carcinoma in situ of the breast.

PubMed

Correa, C; McGale, P; Taylor, C; Wang, Y; Clarke, M; Davies, C; Peto, R; Bijker, N; Solin, L; Darby, S

2010-01-01

Individual patient data were available for all four of the randomized trials that began before 1995, and that compared adjuvant radiotherapy vs no radiotherapy following breast-conserving surgery for ductal carcinoma in situ (DCIS). A total of 3729 women were eligible for analysis. Radiotherapy reduced the absolute 10-year risk of any ipsilateral breast event (ie, either recurrent DCIS or invasive cancer) by 15.2% (SE 1.6%, 12.9% vs 28.1% 2 P <.00001), and it was effective regardless of the age at diagnosis, extent of breast-conserving surgery, use of tamoxifen, method of DCIS detection, margin status, focality, grade, comedonecrosis, architecture, or tumor size. The proportional reduction in ipsilateral breast events was greater in older than in younger women (2P < .0004 for difference between proportional reductions; 10-year absolute risks: 18.5% vs 29.1% at ages <50 years, 10.8% vs 27.8% at ages ≥ 50 years) but did not differ significantly according to any other available factor. Even for women with negative margins and small low-grade tumors, the absolute reduction in the 10-year risk of ipsilateral breast events was 18.0% (SE 5.5, 12.1% vs 30.1%, 2P = .002). After 10 years of follow-up, there was, however, no significant effect on breast cancer mortality, mortality from causes other than breast cancer, or all-cause mortality.

An Andean-type retro-arc foreland system beneath northwest South China revealed by SINOPROBE profiling

NASA Astrophysics Data System (ADS)

Li, Jianhua; Dong, Shuwen; Cawood, Peter A.; Zhao, Guochun; Johnston, Stephen T.; Zhang, Yueqiao; Xin, Yujia

2018-05-01

In the Mesozoic, South China was situated along the convergent margin between the Asian and Pacific plates, providing an excellent laboratory to understand the interactions between deformation, sedimentation and magmatism in a retroarc environment. The crustal architecture of northwest South China is displayed along the ∼600-km-long SINOPROBE deep seismic reflection profiles and reveals from east to west: (1) highly folded and truncated reflectors in the upper crust of the Yangtze Fold Zone, which correspond to thin- and thick-skinned thrust systems, and document large-scale intraplate structural imbrication and shortening; (2) a crustal-scale flat-ramp-flat structure, termed the Main Yangtze decollement, which forms a weak, viscous layer to accommodate strain decoupling and material transport in the thin- and thick-skinned systems; and (3) nearly flat-lying reflectors in the Sichuan Basin, which support interpretation of the basin as a weakly deformed depocentre. The Yangtze Fold Zone and the Sichuan Basin represent a retro-arc foreland basin system that is >800 km away from the continental-margin magmatic arc. We suggest that tectonic processes across the arc and retro-arc systems, including arc magma flare-up, basin sedimentation, retroarc thrust propagation, lithosphere underthrusting, root foundering, and extension-related magmatism were interrelated and governed mass transfer. Age data and geological relations link the tectonic processes to evolving geodynamics of the subducting Paleo-Pacific plate.

Surface and subsurface facies architecture of a small hydroexplosive, rhyolitic centre in the Mesoproterozoic Gawler Range Volcanics, South Australia

NASA Astrophysics Data System (ADS)

Roache, M. W.; Allen, S. R.; McPhie, J.

2000-12-01

At Menninnie Dam, South Australia, a drilling program has revealed a complete section through the subsurface feeder system and erupted products of a small, hydroexplosive, rhyolitic centre within the Mesoproterozoic Gawler Range Volcanics. Porphyritic rhyolite intruded near-vertical faults in the Palaeoproterozoic basement and at less than a few hundred metres depth, interacted with fault-hosted (hot?) groundwater. Hydrofracturing of the wall rock occurred in advance of and at the margins of the rhyolitic intrusions. The rhyolitic intrusions have peperitic margins and grade into discordant lithic-rich PB facies. The advancing fragmentation front intersected the palaeosurface, triggering phreatic eruptions that deposited a poorly sorted, lithic-rich explosion breccia. Rhyolite then rose to the surface through the intrusive breccias and shallow-seated magma-water interaction occurred in the conduit within <50 m of the surface. As the magma discharge rate increased, ;dry; explosive activity prevailed. A fall deposit, the top of which is welded, was deposited close to the vent, and in more distal locations (>800 m from the inferred source), the products include muddy sandstone and pumice breccia. At the end of the eruption, rhyolitic lava was extruded in the form of a small dome. The presence of contemporaneous Pb-Zn-Ag mineralisation in the wall rocks suggests that an active hydrothermal system may have been involved in the formation of the Menninnie Dam hydroexplosive volcanic centre.

Structural and kinematic evolution of the Yukon-Tanana upland tectonites, east-central Alaska: A record of late Paleozoic to Mesozoic crustal assembly

USGS Publications Warehouse

Hansen, V.L.; Dusel-Bacon, C.

1998-01-01

The Yukon-Tanana terrane, the largest tectonostratigraphic terrane in the northern North American Cordillera, is polygenetic and not a single terrane. Lineated and foliated (L-S) tectonites, which characterize the Yukon-Tanana terrane, record multiple deformations and formed at different times. We document the polyphase history recorded by L-S tectonites within the Yukon-Tanana upland, east-central Alaska. These upland tectonites compose a heterogeneous assemblage of deformed igneous and metamorphic rocks that form the Alaskan part of what has been called the Yukon-Tanana composite terrane. We build on previous kinematic data and establish the three-dimensional architecture of the upland tectonites through kinematic and structural analysis of more than 250 oriented samples, including quartz c-axis fabric analysis of 39 samples. Through this study we distinguish allochthonous tectonites from parautochthonous tectonites within the Yukon-Tanana upland. The upland tectonites define a regionally coherent stacking order: from bottom to top, they are lower plate North American parautochthonous attenuated continental margin; continentally derived marginal-basin strata; and upper plate ocean-basin and island-arc rocks, including some continental basement rocks. We delineate three major deformation events in time, space, and structural level across the upland from the United States-Canada border to Fairbanks, Alaska: (1) pre-Early Jurassic (>212 Ma) northeast-directed, apparent margin-normal contraction that affected oceanic rocks; (2) late Early to early Middle Jurassic (>188-185 Ma) northwest-directed, apparent margin-parallel contraction and imbrication that resulted in juxtaposition of the allochthonous tectonites with parautochthonous continental rocks; and (3) Early Cretaceous (135-110 Ma) southeast-directed crustal extension that resulted in exposure of the structurally deepest, parautochthonous continental rocks. The oldest event represents deformation within a west-dipping (present coordinates) Permian-Triassic subduction zone. The second event records Early to Middle Jurassic collision of the arc and subduction complex with North American crust, and the third event reflects mid-Cretaceous southeast-directed crustal extension. Events one and two can be recognized and correlated through southern Yukon, even though this region was affected by mid-Cretaceous dextral shear along steep northwest-striking faults. Our data support a model of crustal assembly originally proposed by D. Tempelman-Kluit in which previously deformed allochthonous rocks were thrust over parautochthonous rocks of the attenuated North American margin in Middle Jurassic time. Approximately 50 m.y. after tectonic accretion, east-central Alaska was dissected by crustal extension, exposing overthrust parautochthonous strata.

Non-random occurrence of Robertsonian translocations in the house mouse (Mus musculus domesticus): is it related to quantitative variation in the minor satellite?

PubMed

Cazaux, Benoîte; Catalan, Josette; Claude, Julien; Britton-Davidian, Janice

2014-01-01

The house mouse, Mus musculus domesticus, shows extraordinary chromosomal diversity driven by fixation of Robertsonian (Rb) translocations. The high frequency of this rearrangement, which involves the centromeric regions, has been ascribed to the architecture of the satellite sequence (high quantity and homogeneity). This promotes centromere-related translocations through unequal recombination and gene conversion. A characteristic feature of Rb variation in this subspecies is the non-random contribution of different chromosomes to the translocation frequency, which, in turn, depends on the chromosome size. Here, the association between satellite quantity and Rb frequency was tested by PRINS of the minor satellite which is the sequence involved in the translocation breakpoints. Five chromosomes with different translocation frequencies were selected and analyzed among wild house mice from 8 European localities. Using a relative quantitative measurement per chromosome, the analysis detected a large variability in signal size most of which was observed between individuals and/or localities. The chromosomes differed significantly in the quantity of the minor satellite, but these differences were not correlated with their translocation frequency. However, the data uncovered a marginally significant correlation between the quantity of the minor satellite and chromosome size. The implications of these results on the evolution of the chromosomal architecture in the house mouse are discussed. © 2014 S. Karger AG, Basel.

Recreation and Simulation of Preindustrial Flour Processes in the Margin of Rivers

NASA Astrophysics Data System (ADS)

Fernández, J. J.; José, J. I.; Martínez-Rubio, J.; Finat, J.

2015-02-01

Manufacture and preindustrial activities have configured infrastructures and commercial development along several centuries. Both regional economic and social environment of the present days can be seen as a consequence of the secular interaction between available physical resources and social tissue along our history. Since ancient times, the economy of Castile and Leon has been based on livestock and agriculture, predominantly represented by cattle and large cereal extensions. Thus, flour industry plays an important role which has been reflected along the Medieval and Renaissance ages in a network of preindustrial installations involving mills and "aceñas" (which are also water-powered mills but set up as larger plants containing different kinds of grinders). In this work we have performed an architectural surveying of a bunch of those large-scale abandoned installations which precede the development of the flour factories that brought the industrial era. Our case of use focuses on the aceñas placed in a strech of the Duero river, between Tordesillas and Toro (Spain). Our work includes the virtual reconstruction of mechanisms and a simulation of the processes that milling involves by using the transformation of hydrodynamical forces into mechanical power. Furthermore the architectural container, our development allows the visualization of the milling machinery running, enriched with a simulation of some aspect of the involved hydrodynamic aspects.

The concept of landscape education at school level with respect to the directions of the science of landscape

NASA Astrophysics Data System (ADS)

Szczęsna, Joanna

2010-01-01

School education is both a starting point for the development of various scientific disciplines (school educates future researchers) and the result of science. The landscape research is conducted within many scientific disciplines and has a long tradition. Lanscape education, which is the result of a scientific dimension, is implemented in primary school under the nature subject. Primary school education is the only level at which the geographical contents are carried out on landscape. The landscape is of interest to many disciplines: geography, architecture, social sciences and the arts. In recent years, there were many studies which contained an overview of the main strands of the science of landscape, presented the differences in the meaning of the concept and objectives of individual research disciplines. These studies have become the ground for the characterization of the concept of landscape education implemented in Polish school and its evaluation in terms of scientific achievements. A review of educational purposes, the basic content of education and achievements of students, demonstrate the influence of multiple scientific disciplines in school landscape education. The most significant share of the course content are achievements of geography disciplines, particularly: physical geography, environmental protection and landscape ecology. Other scientific fields: literature, art, psychology, sociology, and architecture do not have any impact on the school landscape education or their impact remains marginal.

Highstand shelf fans: The role of buoyancy reversal in the deposition of a new type of shelf sand body

USGS Publications Warehouse

Steel, Elisabeth; Simms, Alexander R.; Warrick, Jonathan; Yokoyama, Yusuke

2016-01-01

Although sea-level highstands are typically associated with sediment-starved continental shelves, high sea level does not hinder major river floods. Turbidity currents generated by plunging of sediment-laden rivers at the fluvial-marine interface, known as hyperpycnal flows, allow for cross-shelf transport of suspended sand beyond the coastline. Hyperpycnal flows in southern California have deposited six subaqueous fans on the shelf of the northern Santa Barbara Channel in the Holocene. Using eight cores and nine grab samples, we describe the deposits, age, and stratigraphic architecture of two fans in the Santa Barbara Channel. Fan lobes have up to 3 m of relief and are composed of multiple hyperpycnite beds ∼5 cm to 40 cm thick. Deposit architecture and geometry suggest the hyperpycnal flows became positively buoyant and lifted off the seabed, resulting in well-sorted, structureless, elongate sand lobes. Contrary to conventional sequence stratigraphic models, the presence of these features on the continental shelf suggests that active-margin shelves may locally develop high-quality reservoir sand bodies during sea-level highstands, and that such shelves need not be solely the site of sediment bypass. These deposits may provide a Quaternary analogue to many well-sorted sand bodies in the rock record that are interpreted as turbidites but lack typical Bouma-type features.

Architectural elements from Lower Proterozoic braid-delta and high-energy tidal flat deposits in the Magaliesberg Formation, Transvaal Supergroup, South Africa

NASA Astrophysics Data System (ADS)

Eriksson, Patrick G.; Reczko, Boris F. F.; Jaco Boshoff, A.; Schreiber, Ute M.; Van der Neut, Markus; Snyman, Carel P.

1995-06-01

Three architectural elements are identified in the Lower Proterozoic Magaliesberg Formation (Pretoria Group, Transvaal Supergroup) of the Kaapvaal craton, South Africa: (1) medium- to coarse-grained sandstone sheets; (2) fine- to medium-grained sandstone sheets; and (3) mudrock elements. Both sandstone sheet elements are characterised by horizontal lamination and planar cross-bedding, with lesser trough cross-bedding, channel-fills and wave ripples, as well as minor desiccated mudrock partings, double-crested and flat-topped ripples. Due to the local unimodal palaeocurrent patterns in the medium- to coarse-grained sandstone sheets, they are interpreted as ephemeral braid-delta deposits, which were subjected to minor marine reworking. The predominantly bimodal to polymodal palaeocurrent trends in the fine- to medium-grained sandstone sheets are inferred to reflect high-energy macrotidal processes and more complete reworking of braid-delta sands. The suspension deposits of mudrocks point to either braid-delta channel abandonment, or uppermost tidal flat sedimentation. The depositional model comprises ephemeral braid-delta systems which debouched into a high-energy peritidal environment, around the margins of a shallow epeiric sea on the Kaapvaal craton. Braid-delta and tidal channel dynamics are inferred to have been similar. Fine material in the Magaliesberg Formation peritidal complexes indicates that extensive aeolian removal of clay does not seem applicable to this example of the early Proterozoic.

Occurence of sulfate- and iron-reducing bacteria in stratal waters of the Romashkinskoe oil field

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nazina, T.N.; Ivanova, A.E.; Goulbeva, O.V.

1995-03-01

The occurrence of microorganisms and the rates of terminal biogenic processes-sulfate reduction and methane synthesis-were studied in stratial waters in bed 302 of the Bashkir Carboniferous deposit at the Romashkinskoe oil field. It was shown that bed 302 was a dynamic, highly reduced ecosystem containing sulfates and hydrogen sulfide in considerable concentrations, in which active biogenic processes occurred. Sulfate reduction was a dominating anaerobic process by which the transformation of organic matter occurred. The sulfate-reducing microflora was diverse and characterized by a wide range of metabolic potentials. Enrichment cultures capable of oxidizing many organic substances, such as benzoate, acetate, ethanol,more » or lactate, at the expense of reduction of sulfates and ferric ion were isolated from 302. It was suggested that the sulfate-reducing microflora might be responsible not only for sulfate reduction in the stratum but also for mobilization of some insoluble iron oxides in the oil-bearing rock. These findings indicate that bacteria carrying out dissimilatory reduction of sulfate and iron can contribute to the geochemistry of organic and mineral compounds in subsurface ecosystems. 24 refs., 2 figs., 6 tabs.« less

Lacustrine records of Holocene flood pulse dynamics in the Upper Paraguay River watershed (Pantanal wetlands, Brazil)

USGS Publications Warehouse

McGlue, Michael M.; Silva, Aquinaldo; Zani, Hiran; Corradini, Fabricio A.; Parolin, Mauro; Abel, Erin J.; Cohen, Andrew S.; Assine, Mario L.; Ellis, Geoffrey S.; Trees, Mark A.; Kuerten, Sidney; Gradella, Frederico dos Santos; Rasbold, Giliane Gessica

2012-01-01

The Pantanal is the world's largest tropical wetland and a biodiversity hotspot, yet its response to Quaternary environmental change is unclear. To address this problem, sediment cores from shallow lakes connected to the UpperParaguayRiver (PR) were analyzed and radiocarbon dated to track changes in sedimentary environments. Stratal relations, detrital particle size, multiple biogeochemical indicators, and sponge spicules suggest fluctuating lake-level lowstand conditions between ~ 11,000 and 5300 cal yr BP, punctuated by sporadic and in some cases erosive flood flows. A hiatus has been recorded from ~ 5300 to 2600 cal yr BP, spurred by confinement of the PR within its channel during an episode of profound regional drought. Sustained PR flooding caused a transgression after ~ 2600 cal yr BP, with lake-level highstand conditions appearing during the Little Ice Age. Holocene PR floodpulsedynamics are best explained by variability in effective precipitation, likely driven by insolation and tropical sea-surface temperature gradients. Our results provide novel support for hypotheses on: (1) stratigraphic discontinuity of floodplain sedimentary archives; (2) late Holocene methane flux from Southern Hemisphere wetlands; and (3) pre-colonial indigenous ceramics traditions in western Brazil.

Tectono-stratigraphic evolution of normal fault zones: Thal Fault Zone, Suez Rift, Egypt

NASA Astrophysics Data System (ADS)

Leppard, Christopher William

The evolution of linkage of normal fault populations to form continuous, basin bounding normal fault zones is recognised as an important control on the stratigraphic evolution of rift-basins. This project aims to investigate the temporal and spatial evolution of normal fault populations and associated syn-rift deposits from the initiation of early-formed, isolated normal faults (rift-initiation) to the development of a through-going fault zone (rift-climax) by documenting the tectono-stratigraphic evolution of the Sarbut EI Gamal segment of the exceptionally well-exposed Thai fault zone, Suez Rift, Egypt. A number of dated stratal surfaces mapped around the syn-rift depocentre of the Sarbut El Gamal segment allow constraints to be placed on the timing and style of deformation, and the spatial variability of facies along this segment of the fault zone. Data collected indicates that during the first 3.5 My of rifting the structural style was characterised by numerous, closely spaced, short (< 3 km), low displacement (< 200 m) synthetic and antithetic normal faults within 1 - 2 km of the present-day fault segment trace, accommodating surface deformation associated with the development of a fault propagation monocline above the buried, pre-cursor strands of the Sarbut El Gamal fault segment. The progressive localisation of displacement onto the fault segment during rift-climax resulted in the development of a major, surface-breaking fault 3.5 - 5 My after the onset of rifting and is recorded by the death of early-formed synthetic and antithetic faults up-section, and thickening of syn-rift strata towards the fault segment. The influence of intrabasinal highs at the tips of the Sarbut EI Gamal fault segment on the pre-rift sub-crop level, combined with observations from the early-formed structures and coeval deposits suggest that the overall length of the fault segment was fixed from an early stage. The fault segment is interpreted to have grown through rapid lateral propagation and early linkage of the precursor fault strands at depth before the fault segment broke surface, followed by the accumulation of displacement on the linked fault segment with minimal lateral propagation. This style of fault growth contrasts conventional fault growth models by which growth occurs through incremental increases in both displacement and length through time. The evolution of normal fault populations and fault zones exerts a first- order control on basin physiography and sediment supply, and therefore, the architecture and distribution of coeval syn-rift stratigraphy. The early syn-rift continental, Abu Zenima Formation, to shallow marine, Nukhul Formation show a pronounced westward increase in thickness controlled by the series of synthetic and antithetic faults up to 3 km west of present day Thai fault. The orientation of these faults controlled the location of fluvial conglomerates, sandstones and mudstones that shifted to the topographic lows created. The progressive localisation of displacement onto the Sarbut El Gamal fault segment during rift-climax resulted in an overall change in basin geometry. Accelerated subsidence rates led to sedimentation rates being outpaced by subsidence resulting in the development of a marine, sediment-starved, underfilled hangingwall depocentre characterised by slope-to-basinal depositional environments, with a laterally continuous slope apron in the immediate hangingwall, and point-sourced submarine fans. Controls on the spatial distribution, three dimensional architecture, and facies stacking patterns of coeval syn-rift deposits are identified as: I) structural style of the evolution and linkage of normal fault populations, ii) basin physiography, iii) evolution of drainage catchments, iv) bedrock lithology, and v) variations in sea/lake level.

Architecture of ductile-type, hyper-extended passive margins: Geological constraints from the inverted Cretaceous basin of the North-Pyrenean Zone ('Chaînons Béarnais', Western Pyrenees)

NASA Astrophysics Data System (ADS)

Corre, Benjamin; Lagabrielle, Yves; Labaume, Pierre; Lahfid, Abdeltif; Boulvais, Philippe; Bergamini, Geraldine; Fourcade, Serge; Clerc, Camille

2017-04-01

Sub-continental lithospheric mantle rocks are exhumed at the foot of magma-poor distal passive margins as a response to extreme stretching of the continental crust during plate separation. Remnants of the Northern Iberian paleo-passive margin are now exposed in the North-Pyrenean Zone (NPZ) and represent field analogues to study the processes of continental crust thinning and subcontinental mantle exhumation. The NPZ results from the inversion of basins opened between the Iberia and Europa plates during Albo-Cenomanian times. In the western NPZ, the 'Chaînons Béarnais' ranges display a fold-and-thrust structure involving the Mesozoic sedimentary cover, decoupled from its continental basement and associated with peridotite bodies in tectonic contact with Palaeozoic basement lenses of small size. Continental extension developed under hot thermal conditions, as demonstrated by the syn-metamorphic Cretaceous ductile deformation affecting both the crustal basement and the allochthonous Mesozoic cover. In this study, we present structural and geochemical data providing constraints to reconstruct the evolution of the northern Iberia paleo-margin. Field work confirms that the pre-rift Mesozoic cover is intimately associated to mantle rocks and to thin tectonic lenses of crustal basement. It also shows that the pre-rift cover was detached from its bedrock at the Keuper evaporites level and was welded to mantle rocks during their exhumation at the foot of the hyper-extended margin. The crust/mantle detachment fault is a major shear zone characterized by anastomosed shear bands defining a plurimetric phacoidal fabric at the top of the serpentinized mantle. The detachment is marked by a layer of metasomatic rocks, locally 20 meters thick, made of talc-chlorite-pyrite-rich rocks that developped under greenschist facies conditions. Raman Spectroscopy on Carbonaceous Materials (RSCM), performed on the Mesozoic cover reveal that the entire sedimentary pile underwent temperatures ranging between 200°C and 480°C. We show that: (i) at the site of mantle rocks exhumation, the boudinaged pre-rift sediments have undergone drastic syn-metamorphic thinning with the genesis of a S0/S1 foliation and, (ii) the Paleozoic basement has been ductilely deformed, into thin tectonic lenses that remained welded to the exhumed mantle rocks. Therefore the overall crustal rheology appears dominated by shallow levels having a ductile behavior. This rheology is related to the presence of a thick pre- and syn-rift decoupled cover acting as an efficient thermal blanket. This new geological data set highlights important characteristics of ductile-type hyper-extended passive margin that cannot be obtained from the study of seismic lines. Finally, we stress that studying field analogues represents a major tool to better understand the mechanisms of extreme crustal thinning associated with mantle exhumation and their structural inheritance during tectonic inversion.

Seafloor Morphology And Sediment Discharge Of The Storfjorden And Kveithola Palaeo-Ice Streams (NW Barents Sea) During The Last Deglaciation

NASA Astrophysics Data System (ADS)

Camerlenghi, Angelo; Rebesco, Michele; Pedrosa, Mayte; Demol, Ben; Giulia Lucchi, Renata; Urgeles, Roger; Colmenero-Hidalgo, Elena; Andreassen, Karin; Sverre Laberg, Jan; Winsborrow, Monica

2010-05-01

IPY Activity N. 367 focusing on Neogene ice streams and sedimentary processes on high- latitude continental margins (NICE-STREAMS) resulted in two coordinated cruises on the adjacent Storfjorden and Kveithola trough-mouth fans in the NW Barents Sea: SVAIS Cruise of BIO Hespérides, summer 2007, and EGLACOM Cruise of Cruise R/V OGS-Explora, summer 2008. The objectives were to acquire a high-resolution set of bathymetric, seismic and sediment core data in order to decipher the Neogene architectural development of the glacially-dominated NW Barents Sea continental margin in response to natural climate change. The paleo-ice streams drained ice from southern Spitsbergen, Spitsbergen Bank, and Bear Island. The short distance from the ice source to the calving front produced a short residence time of ice, and therefore a rapid response to climatic changes. In the outer trough of southern Storfjorden, lobate moraines superimpose and are cut by very large linear features attributed to mega-iceberg scours. In the adjacent Kveithola trough, a fresh morphology includes mega-scale glacial lineations overprinted by transverse grounding-zone wedges, diagnostic of episodic ice stream retreat. A 15 m thick glacimarine drape suggests an high post-deglaciation sedimentation rate. Preliminary interpretation suggests that the retreat of the Svalbard/Barents Sea Ice Sheet was highly dynamic and that grounded ice persisted on Spitsbergen Bank for some thousands years after the main Barents Sea deglaciation.The Storfjorden continental slope is divided into three wide lobes. Opposite the two northernmost lobes the slope is dominated by straight gullies in the upper part, and deposition of debris lobes on the mid and lower parts. In contrast, the southernmost lobe is characterized by widespread occurrence of submarine landslides. Sediment failure has accompanied the evolution of the southern Storfjorden and Kveithola margin throughout the Late Neogene, with very large mass transport deposits up to 200 m thick in the early phases of the development of the glacially influenced margin. Conversely, the central and northern parts of the Storfjorden margin have prograded without appreciable episodes of mass failure. Sedimentation has occurred through alternate layering of decimeter-thick glacial debris flows deposits, with laminated and acoustically transparent interglacial sediment drape. Gullies and paleo-gullies incise the glacial debris flows and are covered by the interglacial drape. They are formed early during each deglaciation phase, most likely by the erosive action of short-lived hyperpycnal flows generated by sediment-laden subglacial meltwater discharge. In sediment cores thick finely-laminated sedimentary beds on the upper continental slope of the southern part of the margin indicate preferential deposition by settlement of meltwater sediment plumes. High sedimentation rates of plumites may contribute to the slope instability and suggest that meltwater discharge was focused on the southern Storfjorden and Kveithola paleo-ice streams.

LITHOPROBE East onshore-offshore seismic refraction survey -constraints on interpretation of reflection data in the Newfoundland Appalachians

USGS Publications Warehouse

Marillier, F.; Hall, J.; Hughes, S.; Louden, K.; Reid, I.; Roberts, B.; Clowes, R.; Cote, T.; Fowler, J.; Guest, S.; Lu, H.; Luetgert, J.; Quinlan, G.; Spencer, C.; Wright, J.

1994-01-01

Combined onshore-offshore seismic refraction/ wide-angle reflection data have been acquired across Newfoundland, eastern Canada, to investigate the structural architecture of the northern Appalachians, particularly of distinct crustal zones recognized from earlier LITHOPROBE vertical incidence studies. A western crustal unit, correlated with the Grenville province of the Laurentian plate margin thins from 44 to 40 km and a portion of the lower crust becomes highly reflective with velocities of 7.2 km/s. In central Newfoundland, beneath the central mobile belt, the crust thins to 35 km or less and is marked by average continental velocities, not exceeding 7.0 km/s in the lower crust. Further east, in a crustal unit underlying the Avalon zone and associated with the Gondwanan plate margin, the crust is 40 km thick, and has velocities of 6.8 km/s in the lower crust. Explanations for the thin crust beneath the central mobile belt include (1) post-orogenic isostatic readjustment associated with a density in the mantle which is lower beneath this part of the orogen than beneath the margin, (2) mechanical thinning at the base of the crust during orogenic collapse perhaps caused by delamination, and (3) transformation by phase change of a gabbroic lower crust to eclogite which seismologically would be difficult to distinguish from mantle. Except for a single profile in western Newfoundland, velocities in the crust are of typical continental affinity with lower-crustal velocities less than 7.0 km/s. This indicates that there was no significant magmatic underplating under the Newfoundland Appalachians during Mesozoic rifting of the Atlantic Ocean as proposed elsewhere for the New England Appalachians. A mid-crustal velocity discontinuity observed in the Newfoundland region does not coincide with any consistent reflection pattern on vertical incidence profiles. However, we suggest that localized velocity heterogeneities at mid-crustal depths correspond to organized vertical incidence reflections. ?? 1994.

Basement - Cover decoupling and progressive exhumation of metamorphic sediments at hot rifted margin. Insights from the Northeastern Pyrenean analog

NASA Astrophysics Data System (ADS)

Clerc, Camille; Lagabrielle, Yves; Labaume, Pierre; Ringenbach, Jean-Claude; Vauchez, Alain; Nalpas, Thierry; Bousquet, Romain; Ballard, Jean-François; Lahfid, Abdeltif; Fourcade, Serge

2016-08-01

We compile field data collected along the eastern part of the North Pyrenean Zone (NPZ) to point to a tectonic evolution under peculiar thermal conditions applying to the basin sediments in relation with the opening of the Cretaceous Pyrenean rift. Based on this compilation, we show that when thinning of the continental crust increased, isotherms moved closer to the surface with the result that the brittle-ductile transition propagated upward and reached sediments deposited at the early stage of the basin opening. During the continental breakup, the pre-rift Mesozoic cover was efficiently decoupled from the Paleozoic basement along the Triassic evaporite level and underwent drastic ductile thinning and boudinage. We suggest that the upper Albian and upper Cretaceous flysches acted as a blanket allowing temperature increase in the mobile pre-rift cover. Finally, we show that continuous spreading of the basin floor triggered the exhumation of the metamorphic, ductily sheared pre-rift cover, thus contributing to the progressive thinning of the sedimentary pile. In a second step, we investigate the detailed geological records of such a hot regime evolution along a reference-section of the eastern NPZ. We propose a balanced restoration from the Mouthoumet basement massif (north) to the Boucheville Albian basin (south). This section shows a north to south increase in the HT Pyrenean imprint from almost no metamorphic recrystallization to more than 600 °C in the pre- and syn-rift sediments. From this reconstruction, we propose a scenario of tectonic thinning involving the exhumation of the pre-rift cover by the activation of various detachment surfaces at different levels in the sedimentary pile. In a third step, examination of the architecture of current distal passive margin domains provides confident comparison between the Pyrenean case and modern analogs. Finally, we propose a general evolutionary model for the pre-rift sequence of the Northeastern Pyrenean rifted margin.

Basin geodynamics and sequence stratigraphy of Upper Triassic to Lower Jurassic deposits of Southern Tunisia

NASA Astrophysics Data System (ADS)

Carpentier, Cédric; Hadouth, Suhail; Bouaziz, Samir; Lathuilière, Bernard; Rubino, Jean-Loup

2016-05-01

Aims of this paper are to propose a geodynamic and sequential framework for the late Triassic and early Jurassic of and south Tunisia and to evidence the impact of local tectonics on the stratigraphic architecture. Facies of the Upper Triassic to Lower Jurassic of Southern Tunisia have been interpreted in terms of depositional environments. A sequential framework and correlation schemes are proposed for outcrops and subsurface transects. Nineteen middle frequency sequences inserted in three and a half low frequency transgression/regression cycles were evidenced. Despite some datation uncertainties and the unknown durations of Lower Jurassic cycles, middle frequency sequences appear to be controlled by eustasy. In contrast the tectonics acted as an important control on low frequency cycles. The Carnian flooding was certainly favored by the last stages of a rifting episode which started during the Permian. The regression accompanied by the formation of stacked angular unconformities and the deposition of lowstand deposits during the late Carnian and Norian occured during the uplift and tilting of the northern basin margins. The transpressional activity of the Jeffara fault system generated the uplift of the Tebaga of Medenine high from the late Carnian and led to the Rhaetian regional angular Sidi Stout Unconformity. Facies analysis and well-log correlations permitted to evidence that Rhaetian to Lower Jurassic Messaoudi dolomites correspond to brecciated dolomites present on the Sidi Stout unconformity in the North Dahar area. The Early-cimmerian compressional event is a possible origin for the global uplift of the northern African margin and Western Europe during the late Carnian and the Norian. During the Rhaetian and the early Jurassic a new episode of normal faulting occured during the third low frequency flooding. This tectonosedimentary evolution ranges within the general geodynamic framework of the north Gondwana margin controlled by the opening of both Neotethys and Atlantic oceans.

Age, distribution and style of deformation in Alaska north of 60°N: Implications for assembly of Alaska

USGS Publications Warehouse

Moore, Thomas; Box, Stephen E.

2016-01-01

The structural architecture of Alaska is the product of a complex history of deformation along both the Cordilleran and Arctic margins of North America involving oceanic plates, subduction zones and strike-slip faults and with continental elements of Laurentia, Baltica, and Siberia. We use geological constraints to assign regions of deformation to 14 time intervals and to map their distributions in Alaska. Alaska can be divided into three domains with differing deformational histories. Each domain includes a crustal fragment that originated near Early Paleozoic Baltica. The Northern domain experienced the Early Cretaceous Brookian orogeny, an oceanic arc-continent collision, followed by mid-Cretaceous extension. Early Cretaceous opening of the oceanic Canada Basin rifted the orogen from the Canadian Arctic margin, producing the bent trends of the orogen. The second (Southern) domain consists of Neoproterozoic and younger crust of the amalgamated Peninsular-Wrangellia-Alexander arc terrane and its paired Mesozoic accretionary prism facing the Pacific Ocean basin. The third (Interior) domain, situated between the first two domains and roughly bounded by the Cenozoic dextral Denali and Tintina faults, includes the large continental Yukon Composite and Farewell terranes having different Permian deformational episodes. Although a shared deformation that might mark their juxtaposition by collisional processes is unrecognized, sedimentary linkage between the two terranes and depositional overlap of the boundary with the Northern domain occurred by early Late Cretaceous. Late Late Cretaceous deformation is the first deformation shared by all three domains and correlates temporally with emplacement of the Southern domain against the remainder of Alaska. Early Cenozoic shortening is mild across interior Alaska but is significant in the Brooks Range, and correlates in time with dextral faulting, ridge subduction and counter-clockwise rotation of southern Alaska. Late Cenozoic shortening is significant in southern Alaska inboard of the underthrusting Yakutat terrane at the Pacific margin and in northeastern Alaska.

A generalized sizing method for revolutionary concepts under probabilistic design constraints

NASA Astrophysics Data System (ADS)

Nam, Taewoo

Internal combustion (IC) engines that consume hydrocarbon fuels have dominated the propulsion systems of air-vehicles for the first century of aviation. In recent years, however, growing concern over rapid climate changes and national energy security has galvanized the aerospace community into delving into new alternatives that could challenge the dominance of the IC engine. Nevertheless, traditional aircraft sizing methods have significant shortcomings for the design of such unconventionally powered aircraft. First, the methods are specialized for aircraft powered by IC engines, and thus are not flexible enough to assess revolutionary propulsion concepts that produce propulsive thrust through a completely different energy conversion process. Another deficiency associated with the traditional methods is that a user of these methods must rely heavily on experts' experience and advice for determining appropriate design margins. However, the introduction of revolutionary propulsion systems and energy sources is very likely to entail an unconventional aircraft configuration, which inexorably disqualifies the conjecture of such "connoisseurs" as a means of risk management. Motivated by such deficiencies, this dissertation aims at advancing two aspects of aircraft sizing: (1) to develop a generalized aircraft sizing formulation applicable to a wide range of unconventionally powered aircraft concepts and (2) to formulate a probabilistic optimization technique that is able to quantify appropriate design margins that are tailored towards the level of risk deemed acceptable to a decision maker. A more generalized aircraft sizing formulation, named the Architecture Independent Aircraft Sizing Method (AIASM), was developed for sizing revolutionary aircraft powered by alternative energy sources by modifying several assumptions of the traditional aircraft sizing method. Along with advances in deterministic aircraft sizing, a non-deterministic sizing technique, named the Probabilistic Aircraft Sizing Method (PASM), was developed. The method allows one to quantify adequate design margins to account for the various sources of uncertainty via the application of the chance-constrained programming (CCP) strategy to AIASM. In this way, PASM can also provide insights into a good compromise between cost and safety.

Assessment of the 802.11g Wireless Protocol for Lunar Surface Communications

NASA Technical Reports Server (NTRS)

Chelmins, David T.; Bguyen, Hung D.; Foore, Lawrence R.

2009-01-01

Future lunar surface missions supporting the NASA Vision for Space Exploration will rely on wireless networks to transmit voice and data. The ad hoc network architecture is of particular interest since it does not require a complex infrastructure. In this report, we looked at data performance over an ad hoc network with varying distances between Apple AirPort wireless cards. We developed a testing program to transmit data packets at precise times and then monitored the receive time to characterize connection delay, packet loss, and data rate. Best results were received for wireless links of less than 75 ft, and marginally acceptable (25-percent) packet loss was received at 150 ft. It is likely that better results will be obtained on the lunar surface because of reduced radiofrequency interference; however, higher power transmitters or receivers will be needed for significant performance gains.

Praxis-based research networks: An emerging paradigm for research that is rigorous, relevant, and inclusive.

PubMed

Werner, James J; Stange, Kurt C

2014-01-01

Practice-based research networks (PBRNs) have developed a grounded approach to conducting practice-relevant and translational research in community practice settings. Seismic shifts in the health care landscape are shaping PBRNs that work across organizational and institutional margins to address complex problems. Praxis-based research networks combine PBRN knowledge generation with multistakeholder learning, experimentation, and application of practical knowledge. The catalytic processes in praxis-based research networks are cycles of action and reflection based on experience, observation, conceptualization, and experimentation by network members and partners. To facilitate co-learning and solution-building, these networks have a flexible architecture that allows pragmatic inclusion of stakeholders based on the demands of the problem and the needs of the network. Praxis-based research networks represent an evolving trend that combines the core values of PBRNs with new opportunities for relevance, rigor, and broad participation. © Copyright 2014 by the American Board of Family Medicine.

Ka-band MMIC subarray technology program (Ka-Mist)

NASA Technical Reports Server (NTRS)

Pottenger, Warren

1995-01-01

The broad objective of this program was to demonstrate a proof of concept insertion of Monolithic Microwave Integrated Circuit (MMIC) device technology into an innovative (tile architecture) active phased array antenna application supporting advanced EHF communication systems. Ka-band MMIC arrays have long been considered as having high potential for increasing the capability of space, aircraft, and land mobile communication systems in terms of scan performance, data rate, link margin, and flexibility while offering a significant reduction in size, weight, and power consumption. Insertion of MMIC technology into antenna systems, particularly at millimeter wave frequencies using low power and low noise amplifiers in close proximity to the radiating elements, offers a significant improvement in the array transmit efficiency, receive system noise figure, and overall array reliability. Application of active array technology also leads to the use of advanced beamforming techniques that can improve beam agility, diversity, and adaptivity to complex signal environments.

Intelligent Control and Health Monitoring. Chapter 3

NASA Technical Reports Server (NTRS)

Garg, Sanjay; Kumar, Aditya; Mathews, H. Kirk; Rosenfeld, Taylor; Rybarik, Pavol; Viassolo, Daniel E.

2009-01-01

Advanced model-based control architecture overcomes the limitations state-of-the-art engine control and provides the potential of virtual sensors, for example for thrust and stall margin. "Tracking filters" are used to adapt the control parameters to actual conditions and to individual engines. For health monitoring standalone monitoring units will be used for on-board analysis to determine the general engine health and detect and isolate sudden faults. Adaptive models open up the possibility of adapting the control logic to maintain desired performance in the presence of engine degradation or to accommodate any faults. Improved and new sensors are required to allow sensing at stations within the engine gas path that are currently not instrumented due in part to the harsh conditions including high operating temperatures and to allow additional monitoring of vibration, mass flows and energy properties, exhaust gas composition, and gas path debris. The environmental and performance requirements for these sensors are summarized.

Motivation for DOC III: 64-bit digital optical computer

NASA Astrophysics Data System (ADS)

Guilfoyle, Peter S.

1991-09-01

This paper suggests a new class of digital logic. OptiComp has focused on a digital optical logic family in order to capitalize on the inherent benefits of optical computing, which include (1) high FAN-IN and FAN-OUT, (2) low power consumption, (3) high noise margin, (4) high algorithmic efficiency using 'smart' interconnects, (5) free space leverage of GIBP (gate interconnect bandwidth product). Other well-known secondary advantages of optical logic include (but are not limited to) zero capacitive loading of signals at a detector, zero cross-talk between signals, zero signal dispersion, minimal clock skew (a few picoseconds or less in an imaging system). The primary focus of this paper is to demonstrate how each of the five advantages can be used to leverage other logic family performance such as GaAs; the secondary attributes will be discussed only in the context of introducing the DOC III architecture.

Motivation for DOC III: 64-bit digital optical computer

NASA Astrophysics Data System (ADS)

Guilfoyle, Peter S.

1991-09-01

The objective of this paper is to motivate a new class of digital logic. OptiComp has focused on a digital optical logic family in order to capitalize on the inherent benefits of optical computing, which include: (1) high FAN-IN and FAN-OUT, (2) low power consumption, (3) high noise margin, (4) high algorithmic efficiency using 'smart' interconnects, (5) free space leverage of GIBP (gate interconnect bandwidth product). Other well-known secondary advantages of optical logic include (but are not limited to): zero capacitive loading of signals at a detector, zero cross-talk between signals, zero signal dispersion, and minimal clock skew (a few picoseconds or less in an imaging system). The primary focus of this paper is on demonstrating how each of the five advantages can be used to leverage other logic family performance such as GaAs; the secondary attributes will be discussed only in the context of introducing the DOC III architecture.

Engineering the Bacterial Microcompartment Domain for Molecular Scaffolding Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Young, Eric J.; Burton, Rodney; Mahalik, Jyoti P.

As synthetic biology advances the intricacy of engineered biological systems, the importance of spatial organization within the cellular environment must not be marginalized. Increasingly, biological engineers are investigating means to control spatial organization within the cell, mimicking strategies used by natural pathways to increase flux and reduce cross-talk. A modular platform for constructing a diverse set of defined, programmable architectures would greatly assist in improving yields from introduced metabolic pathways and increasing insulation of other heterologous systems. Here, we review recent research on the shell proteins of bacterial microcompartments and discuss their potential application as “building blocks” for a rangemore » of customized intracellular scaffolds. As a result, we summarize the state of knowledge on the self-assembly of BMC shell proteins and discuss future avenues of research that will be important to realize the potential of BMC shell proteins as predictively assembling and programmable biological materials for bioengineering.« less

Engineering the Bacterial Microcompartment Domain for Molecular Scaffolding Applications

DOE PAGES

Young, Eric J.; Burton, Rodney; Mahalik, Jyoti P.; ...

2017-07-31

As synthetic biology advances the intricacy of engineered biological systems, the importance of spatial organization within the cellular environment must not be marginalized. Increasingly, biological engineers are investigating means to control spatial organization within the cell, mimicking strategies used by natural pathways to increase flux and reduce cross-talk. A modular platform for constructing a diverse set of defined, programmable architectures would greatly assist in improving yields from introduced metabolic pathways and increasing insulation of other heterologous systems. Here, we review recent research on the shell proteins of bacterial microcompartments and discuss their potential application as “building blocks” for a rangemore » of customized intracellular scaffolds. As a result, we summarize the state of knowledge on the self-assembly of BMC shell proteins and discuss future avenues of research that will be important to realize the potential of BMC shell proteins as predictively assembling and programmable biological materials for bioengineering.« less

Structure of the central Terror Rift, western Ross Sea, Antarctica

USGS Publications Warehouse

Hall, Jerome; Wilson, Terry; Henrys, Stuart

2007-01-01

The Terror Rift is a zone of post-middle Miocene faulting and volcanism along the western margin of the West Antarctic Rift System. A new seismic data set from NSF geophysical cruise NBP04-01, integrated with the previous dataset to provide higher spatial resolution, has been interpreted in this study in order to improve understanding of the architecture and history of the Terror Rift. The Terror Rift contains two components, a structurally-controlled rollover anticlinal arch intruded by younger volcanic bodies and an associated synclinal basin. Offsets and trend changes in fault patterns have been identified, coincident with shifts in the location of depocenters that define rift sub-basins, indicating that the Terror Rift is segmented by transverse structures. Multiple phases of faulting all post-date 17 Ma, including faults cutting the seafloor surface, indicating Neogene rifting and possible modern activity.

Crustal architecture and tectonic evolution of the Cauvery Suture Zone, southern India

NASA Astrophysics Data System (ADS)

Chetty, T. R. K.; Yellappa, T.; Santosh, M.

2016-11-01

The Cauvery suture zone (CSZ) in southern India has witnessed multiple deformations associated with multiple subduction-collision history, with incorporation of the related accretionary belts sequentially into the southern continental margin of the Archaean Dharwar craton since Neoarchean to Neoproterozoic. The accreted tectonic elements include suprasubduction complexes of arc magmatic sequences, high-grade supracrustals, thrust duplexes, ophiolites, and younger intrusions that are dispersed along the suture. The intra-oceanic Neoarchean-Neoproterozoic arc assemblages are well exposed in the form of tectonic mélanges dominantly towards the eastern sector of the CSZ and are typically subjected to complex and multiple deformation events. Multi-scale analysis of structural elements with detailed geological mapping of the sub-regions and their structural cross sections, geochemical and geochronological data and integrated geophysical observations suggest that the CSZ is an important zone that preserves the imprints of multiple cycles of Precambrian plate tectonic regimes.

Engineering the Bacterial Microcompartment Domain for Molecular Scaffolding Applications

PubMed Central

Young, Eric J.; Burton, Rodney; Mahalik, Jyoti P.; Sumpter, Bobby G.; Fuentes-Cabrera, Miguel; Kerfeld, Cheryl A.; Ducat, Daniel C.

2017-01-01

As synthetic biology advances the intricacy of engineered biological systems, the importance of spatial organization within the cellular environment must not be marginalized. Increasingly, biological engineers are investigating means to control spatial organization within the cell, mimicking strategies used by natural pathways to increase flux and reduce cross-talk. A modular platform for constructing a diverse set of defined, programmable architectures would greatly assist in improving yields from introduced metabolic pathways and increasing insulation of other heterologous systems. Here, we review recent research on the shell proteins of bacterial microcompartments and discuss their potential application as “building blocks” for a range of customized intracellular scaffolds. We summarize the state of knowledge on the self-assembly of BMC shell proteins and discuss future avenues of research that will be important to realize the potential of BMC shell proteins as predictively assembling and programmable biological materials for bioengineering. PMID:28824573

Parallel photonic information processing at gigabyte per second data rates using transient states

NASA Astrophysics Data System (ADS)

Brunner, Daniel; Soriano, Miguel C.; Mirasso, Claudio R.; Fischer, Ingo

2013-01-01

The increasing demands on information processing require novel computational concepts and true parallelism. Nevertheless, hardware realizations of unconventional computing approaches never exceeded a marginal existence. While the application of optics in super-computing receives reawakened interest, new concepts, partly neuro-inspired, are being considered and developed. Here we experimentally demonstrate the potential of a simple photonic architecture to process information at unprecedented data rates, implementing a learning-based approach. A semiconductor laser subject to delayed self-feedback and optical data injection is employed to solve computationally hard tasks. We demonstrate simultaneous spoken digit and speaker recognition and chaotic time-series prediction at data rates beyond 1Gbyte/s. We identify all digits with very low classification errors and perform chaotic time-series prediction with 10% error. Our approach bridges the areas of photonic information processing, cognitive and information science.

Technology Overview and Assessment for Small-Scale EDL Systems

NASA Technical Reports Server (NTRS)

Heidrich, Casey R.; Smith, Brandon P.; Braun, Robert D.

2016-01-01

Motivated by missions to land large rovers and humans at Mars and other bodies, high-mass EDL technologies are a prevalent trend in the research community. In contrast, EDL systems for low-mass payloads have attracted less attention. Significant potential in science and discovery exists in small-scale EDL systems. Payloads acting secondary to a flagship mission are a currently under-utilzed resource. Before taking advantage of these opportunities, further developed of scaled EDL technologies is required. The key limitations identified in this study are compact decelerators and deformable impact systems. Current technologies may enable rough landing of small payloads, with moderate restrictions in packaging volume. Utilization of passive descent and landing stages will greatly increase the applicability of small systems, allowing for vehicles robust to entry environment uncertainties. These architectures will provide an efficient means of achieving science and support objectives while reducing cost and risk margins of a parent mission.

High-speed all-optical logic inverter based on stimulated Raman scattering in silicon nanocrystal.

PubMed

Sen, Mrinal; Das, Mukul K

2015-11-01

In this paper, we propose a new device architecture for an all-optical logic inverter (NOT gate), which is cascadable with a similar device. The inverter is based on stimulated Raman scattering in silicon nanocrystal waveguides, which are embedded in a silicon photonic crystal structure. The Raman response function of silicon nanocrystal is evaluated to explore the transfer characteristic of the inverter. A maximum product criterion for the noise margin is taken to analyze the cascadability of the inverter. The time domain response of the inverter, which explores successful inversion operation at 100 Gb/s, is analyzed. Propagation delay of the inverter is on the order of 5 ps, which is less than the delay in most of the electronic logic families as of today. Overall dimension of the device is around 755  μm ×15  μm, which ensures integration compatibility with the matured silicon industry.

New deglacial and Holocene micropaleontological and geochemical records from the southern margin of the Svalbard Archipelago (Arctic Ocean)

NASA Astrophysics Data System (ADS)

Rigual-Hernández, Andrés.

2010-05-01

This study is presented in the context of the Spanish research project "The development of an Arctic ice stream-dominated sedimentary system: The southern Svalbard continental margin" (SVAIS), developed within the framework of the International Polar Year (IPY) Activity N. 367 (NICE STREAMS). Its main goal is to understand the evolution of glacial continental margins and their relationship with the changes in ice sheet dynamics induced by natural climatic changes, combining the geophysical data with the sediment record both collected during an oceanographic cruise in the Storfjorden area (SW Svalbard margin) in August 2007. This marine depositional system, dominated by an ice stream during the last glacial period, was selected due to its small size inducing a rapid response to climatic changes, and for the oceanographic relevance of the area for global ocean circulation. The results obtained aim to define the sedimentary architecture and morphology, and to provide more insight into the paleoceanographic and paleoclimatic evolution of the region. We specifically report on new micropaleontological and geochemical data obtained from the sediment cores. A preliminary age model indicates that the sediment sequences cover approximately the Last Deglaciation and the Holocene. Microfossils are generally well preserved, although the abundances of the different groups show marked shifts along the record. Low concentrations of coccolithophores, diatoms, planktic foraminifers and cysts of organic-walled dinoflagellates (dinocysts) are found at the lower half of the sequence (IRD-rich, coarser-grained sediments), and increase towards the Late Holocene (fine-grained bioturbated sediments). The Climatic Optimum is characterized by the warmest sea surface temperatures as estimated from the fossil assemblage, diverse transfer functions and biogeochemical proxies, and by high nutrient contents in the bottom waters shown by light carbon isotope values and high Cd/Ca ratios in benthic foraminifers. Dilution by terrigenous material, related to the retreat of the Barents Sea Ice Sheet in response to changes in the strength of the Atlantic-sourced, warm Western Spitsbergen Current, seems to be important in driving the abundances of microfossils and of organic compounds. The different stages of the Deglaciation and the Holocene and the associated modifications in the surface oceanic environment are documented by changes in the fossil assemblage composition of the different microfossil groups, while synchronous changes in the bottom water masses are registered by stable isotope and trace element analyses of benthic foraminifers.

Architectural Blueprint for Plate Boundary Observatories based on interoperable Data Management Platforms

NASA Astrophysics Data System (ADS)

Kerschke, D. I.; Häner, R.; Schurr, B.; Oncken, O.; Wächter, J.

2014-12-01

Interoperable data management platforms play an increasing role in the advancement of knowledge and technology in many scientific disciplines. Through high quality services they support the establishment of efficient and innovative research environments. Well-designed research environments can facilitate the sustainable utilization, exchange, and re-use of scientific data and functionality by using standardized community models. Together with innovative 3D/4D visualization, these concepts provide added value in improving scientific knowledge-gain, even across the boundaries of disciplines. A project benefiting from the added value is the Integrated Plate boundary Observatory in Chile (IPOC). IPOC is a European-South American network to study earthquakes and deformation at the Chilean continental margin and to monitor the plate boundary system for capturing an anticipated great earthquake in a seismic gap. In contrast to conventional observatories that monitor individual signals only, IPOC captures a large range of different processes through various observation methods (e.g., seismographs, GPS, magneto-telluric sensors, creep-meter, accelerometer, InSAR). For IPOC a conceptual design has been devised that comprises an architectural blueprint for a data management platform based on common and standardized data models, protocols, and encodings as well as on an exclusive use of Free and Open Source Software (FOSS) including visualization components. Following the principles of event-driven service-oriented architectures, the design enables novel processes by sharing and re-using functionality and information on the basis of innovative data mining and data fusion technologies. This platform can help to improve the understanding of the physical processes underlying plate deformations as well as the natural hazards induced by them. Through the use of standards, this blueprint can not only be facilitated for other plate observing systems (e.g., the European Plate Observing System EPOS), it also supports integrated approaches to include sensor networks that provide complementary processes for dynamic monitoring. Moreover, the integration of such observatories into superordinate research infrastructures (federation of virtual observatories) will be enabled.

Central Atlantic Break-up: A competition between CAMP Hotspot and thinning rate.

NASA Astrophysics Data System (ADS)

Sapin, F.; Maurin, T.

2017-12-01

The break-up of the Central Atlantic is known to have ended at about 190Myrs while the CAMP (Central Atlantic Magmatic Province) was still active. Several seismic lines, acquired recently in the deep offshore Senegal and Mauritanian domain, provide detailed images of continent-ocean transition and the oceanic crust architecture. Their interpretation is the opportunity to describe the progressive interaction between the hot spot activity, the architecture and timing of break up and the oceanic crust production. In the North, seismic data and gravity/magnetic inversions suggest an extremely thinned continental crust with possible mantle exhumation. In the South, the continental crust is thick and the transition to oceanic crust is sharp. In addition, three oceanic crust facies were described along the margin in an extremely slow spreading ridge setting ( 0.8cm/yr during the first 20Myrs): facies (1) with a poorly imaged Moho and a strongly faulted thin oceanic crust or exhumed mantle; facies (2) with an extensively faulted 6km thick oceanic crust; facies (3) with abnormally thick (9km) oceanic crust marked by SDR-type reflections. They are diachronous from North to South and the two first one disappear southwards and (facies 3) being younger toward the North. Only a single very thick oceanic crust (12-14km) remains in front of the Guinea Plateau. We concluded that, in the South, the break-up had been forced through a thick or thickened continental crust due to the remnant activity of the CAMP Hotspot. In the North, the magmatic pulse arrived far after the break-up during the spreading and the thinning of the continental crust could lead to hyper extension. This evolution emphasizes that the architecture, and thus processes leading to the break-up can vary a lot considering the influence of thermal vertical forces (mantle dynamics/hotspot/magmatism) and mechanical horizontal forces (plate movement/faulting/spreading), both of them being necessary for a rift to succeed.

Thermal history and differential exhumation across the Eastern Musgrave Province, South Australia: Insights from low-temperature thermochronology

NASA Astrophysics Data System (ADS)

Glorie, Stijn; Agostino, Kate; Dutch, Rian; Pawley, Mark; Hall, James; Danišík, Martin; Evans, Noreen J.; Collins, Alan S.

2017-04-01

Multi-method geo- and thermochronological data obtained for Palaeo- and Mesoproterozoic granitoids traversing the main structural architecture of the eastern Musgrave Province within South Australia reveal multiphase cooling histories. Apatite U-Pb dating on six samples yield consistent ages of 1075-1025 Ma, suggesting a thermal reset coinciding with mantle-derived magmatism of the greater Warakurna Large Igneous Province ( 1080-1040 Ma). Apatite fission track (AFT) analysis indicate that four discrete thermal events affected the study area, inducing cooling through the AFT partial annealing zone ( 60-120 °C), supported by apatite and zircon (U-Th-Sm)/He data. Late Neoproterozoic cooling from deep crustal levels to temperatures < 200 °C was discerned, which is thought to be related to exhumation and denudation during the Petermann Orogeny. Subsequent cooling events at 450-400 Ma (Silurian-Devonian) and 310-290 Ma (Late Carboniferous) are interpreted to represent exhumation associated with the Alice Springs Orogeny. The latter event exhumed the sampled plutons to shallow crustal depths. An additional Triassic - early Jurassic thermal event, likely recording elevated geothermal gradients at that time, was observed throughout the study area, however, more data is needed to further support this interpretation. The high sample density across the structural architecture of the study area furthermore reveals patterns of fault reactivation and resulting differential exhumation, indicating shallower exhumation levels in the centre and deeper exhumation towards the margins of the sampled transect. The observed differential exhumation patterns match with existing seismic data and fit a model of an inverted graben system for the Phanerozoic evolution of the eastern Musgraves. The results highlight a complex Phanerozoic thermal history for the eastern Musgraves and help to elucidate the poorly appreciated tectonic evolution of inland Australia. This study further demonstrates how high-density sample transects across structural architecture can assess the relative crustal level and associated preservation of the thermal history record within fault-reactivated terranes.

Evaluation of dual multi-mission space exploration vehicle operations during simulated planetary surface exploration

NASA Astrophysics Data System (ADS)

Abercromby, Andrew F. J.; Gernhardt, Michael L.; Jadwick, Jennifer

2013-10-01

IntroductionA pair of small pressurized rovers (multi-mission space exploration vehicles, or MMSEVs) is at the center of the Global Point-of-Departure architecture for future human lunar exploration. Simultaneous operation of multiple crewed surface assets should maximize productive crew time, minimize overhead, and preserve contingency return paths. MethodsA 14-day mission simulation was conducted in the Arizona desert as part of NASA's 2010 Desert Research and Technology Studies (DRATS) field test. The simulation involved two MMSEV earth-gravity prototypes performing geological exploration under varied operational modes affecting both the extent to which the MMSEVs must maintain real-time communications with the mission control center (Continuous [CC] versus Twice-a-Day [2/D]) and their proximity to each other (Lead-and-Follow [L&F] versus Divide-and-Conquer [D&C]). As part of a minimalist lunar architecture, no communication relay satellites were assumed. Two-person crews (an astronaut and a field geologist) operated each MMSEV, day and night, throughout the entire 14-day mission, only leaving via the suit ports to perform simulated extravehicular activities. Metrics and qualitative observations enabled evaluation of the extent to which the operating modes affected productivity and scientific data quality (SDQ). Results and discussionSDQ was greater during CC mode than during 2/D mode; metrics showed a marginal increase while qualitative assessments suggested a practically significant difference. For the communications architecture evaluated, significantly more crew time (14% per day) was required to maintain communications during D&C than during L&F (5%) or 2/D (2%), increasing the time required to complete all traverse objectives. Situational awareness of the other vehicle's location, activities, and contingency return constraints were qualitatively enhanced during L&F and 2/D modes due to line-of-sight and direct MMSEV-to-MMSEV communication. Future testing will evaluate approaches to operating without real-time space-to-earth communications and will include quantitative evaluation and comparison of the efficacy of mission operations, science operations, and public outreach operations.

Significance and outcome of nuclear anaplasia and mitotic index in prostatic adenocarcinomas.

PubMed

Kır, Gozde; Sarbay, Billur Cosan; Gumus, Eyup

2016-10-01

The Gleason grading system measures architectural differentiation and disregards nuclear atypia and the cell proliferation index. Several studies have reported that nuclear grade and mitotic index (MI) are prognostically useful. This study included 232 radical prostatectomy specimens. Nuclear anaplasia (NA) was determined on the basis of nucleomegali (at least 20µm); vesicular chromatin; eosinophilic macronucleoli, nuclear lobulation, and irregular thickened nuclear membranei. The proportion of area of NA was recorded in each tumor in 10% increments. The MI was defined as the number of mitotic figures in 10 consecutive high-power fields (HPF). In univariate analysis, significant differences included associations between biochemical prostate-specific antigen recurrence (BCR) and Gleason score, extraprostatic extension, positive surgical margin, the presence of high-pathologic stage, NA≥10% of tumor area, MI≥3/10 HPF, and preoperative prostate-specific antigen. In a stepwise Cox regression model, a positive surgical margin, the presence of a NA≥10% of tumor area, and a MI of≥3/10 HPF were independent predictors of BCR after radical prostatectomy. NA≥10% of tumor area appeared to have a stronger association with outcome than MI≥3/10 HPF, as still associated with BCR when Gleason score was in the model. The results of our study showed that, in addition to the conventional Gleason grading system, NA, and MI are useful prognostic parameters while evaluating long-term prognosis in prostatic adenocarcinoma. Copyright © 2016 Elsevier Inc. All rights reserved.

Timing and Magnitude of Upper Crustal Shortening in the Gonghe Basin Region of the Northeastern Tibetan Plateau

NASA Astrophysics Data System (ADS)

Craddock, W. H.; Kirby, E.; Harkins, N.; Zhang, H.

2008-12-01

Characterizing the space-time patterns of the growth of high topography in Asia is an important step toward a deeper understanding of the mechanics of intracontinental deformation and its influence on global climate. In northeastern Tibet, there is emerging evidence that a number of ranges around the margins of the plateau experienced a pulse of deformation in the Late Miocene (ca. 12-8 Ma). It remains uncertain, however, whether this event was confined to the margins of the plateau, or whether interior regions deformed synchronously. Here we present a preliminary assessment of the timing and magnitude of upper crustal shortening along the margins of the Gonghe-Tongde basin complex. The Gonghe basin is located at the boundary between the high plateau of central Tibet and the southern flank of the Qilian Shan, and as such it is well-suited as a site to begin reconstructing patterns of plateau growth. The basin is overthrust by two regionally-extensive fault systems, the Qinghai Nan Shan (QNS) fault system on the north side and the Gonghe Nan Shan (GNS) fault system on the south side. Both fault systems are associated with deformation of Tertiary strata; variations in dip, sedimentary facies, and provenance are used to interpret the onset of growth along the margins of the Gonghe basin. A combination of the architecture of pre- and syntectonic basin strata, field measurements of fault dip, fault plane solutions, and topographic analysis of fold backlimbs for the GNS and QNS leads us to infer that the fault systems are a) trishear fault propagation style thrust faults and b) south vergent, with ~30 degree fault ramps soleing into a gently dipping decollement. Reconstructions of fold evolution suggest that the area has experienced > 5 km of upper crustal shortening in the late Cenozoic. A combination of magnetostratigraphy, biostratigraphy and cosmogenic burial ages provides preliminary age control. South of the GNS, a 250 m thick package of growth related strata are found to be 3.4 - 0.5 Ma. A 500 m thick exposure of growth strata on the north side of the range is also interpreted to be Plio-Quaternary in age. At present, however, we can only place a minimum bound on the onset of deformation of ca. 4-5 Ma. In light of a companion study interpreting the onset of deformation along the QNS at >= 5-7 Ma (Zhang H., in review), deformation of the Gonghe region appears to be slightly more recent than at the plateau margins. Historic seismicity and deformation of late-Quaternary alluvial surfaces on both fault systems indicate that these structures have remained active into the Pleistocene.

How important are rare variants in common disease?

PubMed

Saint Pierre, Aude; Génin, Emmanuelle

2014-09-01

Genome-wide association studies have uncovered hundreds of common genetic variants involved in complex diseases. However, for most complex diseases, these common genetic variants only marginally contribute to disease susceptibility. It is now argued that rare variants located in different genes could in fact play a more important role in disease susceptibility than common variants. These rare genetic variants were not captured by genome-wide association studies using single nucleotide polymorphism-chips but with the advent of next-generation sequencing technologies, they have become detectable. It is now possible to study their contribution to common disease by resequencing samples of cases and controls or by using new genotyping exome arrays that cover rare alleles. In this review, we address the question of the contribution of rare variants in common disease by taking the examples of different diseases for which some resequencing studies have already been performed, and by summarizing the results of simulation studies conducted so far to investigate the genetic architecture of complex traits in human. So far, empirical data have not allowed the exclusion of many models except the most extreme ones involving only a small number of rare variants with large effects contributing to complex disease. To unravel the genetic architecture of complex disease, case-control data will not be sufficient, and alternative study designs need to be proposed together with methodological developments. © The Author 2014. Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Poplar PtabZIP1-like enhances lateral root formation and biomass growth under drought stress

DOE PAGES

Dash, Madhumita; Yordanov, Yordan S.; Georgieva, Tatyana; ...

2017-02-10

Developing drought-resistance varieties is a major goal for bioenergy crops, such as poplar (Populus), which will be grown on marginal lands with little or no water input. Root architecture can affect drought resistance, but few genes that affect root architecture in relation to water availability have been identified. Here in this study, using activation tagging in the prime bioenergy crop poplar, we have identified a mutant that overcomes the block of lateral root (LR) formation under osmotic stress. Positioning of the tag, validation of the activation and recapitulation showed that the phenotype is caused by the poplar PtabZIP1-like (PtabZIP1L) genemore » with highest homology to bZIP1 from Arabidopsis. PtabZIP1L is predominantly expressed in roots, particularly in zones where lateral root primordia (LRP) initiate and LR differentiate and emerge. Transgenics overexpressing PtabZIP1L showed precocious LRP and LR development, while PtabZIP1L suppression significantly delayed both LRP and LR formation. Transgenic overexpression and suppression of PtabZIP1L also resulted in modulation of key metabolites like proline, asparagine, valine and several flavonoids. Consistently, expression of both of the poplar Proline Dehydrogenase orthologs and two of the Flavonol Synthases genes was also increased and decreased in overexpressed and suppressed transgenics, respectively. These findings suggest that PtabZIP1L mediates LR development and drought resistance through modulation of multiple metabolic pathways.« less

Poplar PtabZIP1-like enhances lateral root formation and biomass growth under drought stress

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dash, Madhumita; Yordanov, Yordan S.; Georgieva, Tatyana

Developing drought-resistance varieties is a major goal for bioenergy crops, such as poplar (Populus), which will be grown on marginal lands with little or no water input. Root architecture can affect drought resistance, but few genes that affect root architecture in relation to water availability have been identified. Here in this study, using activation tagging in the prime bioenergy crop poplar, we have identified a mutant that overcomes the block of lateral root (LR) formation under osmotic stress. Positioning of the tag, validation of the activation and recapitulation showed that the phenotype is caused by the poplar PtabZIP1-like (PtabZIP1L) genemore » with highest homology to bZIP1 from Arabidopsis. PtabZIP1L is predominantly expressed in roots, particularly in zones where lateral root primordia (LRP) initiate and LR differentiate and emerge. Transgenics overexpressing PtabZIP1L showed precocious LRP and LR development, while PtabZIP1L suppression significantly delayed both LRP and LR formation. Transgenic overexpression and suppression of PtabZIP1L also resulted in modulation of key metabolites like proline, asparagine, valine and several flavonoids. Consistently, expression of both of the poplar Proline Dehydrogenase orthologs and two of the Flavonol Synthases genes was also increased and decreased in overexpressed and suppressed transgenics, respectively. These findings suggest that PtabZIP1L mediates LR development and drought resistance through modulation of multiple metabolic pathways.« less

Crustal architecture and deep structure of the Namibian passive continental margin around Walvis Ridge from wide-angle seismic data

NASA Astrophysics Data System (ADS)

Behrmann, Jan H.; Planert, Lars; Jokat, Wilfried; Ryberg, Trond; Bialas, Jörg; Jegen, Marion

2013-04-01

The opening of the South Atlantic ocean basin was accompanied by voluminous magmatism on the conjugate continental margins of Africa and South America, including the formation of the Parana and Entendeka large igneous provinces (LIP), the build-up of up to 100 km wide volcanic wedges characterized by seaward dipping reflector sequences (SDR), as well as the formation of paired hotspot tracks on the rifted African and South American plates, the Walvis Ridge and the Rio Grande Rise. The area is considered as type example for hotspot or plume-related continental break-up. However, SDR, and LIP-related features on land are concentrated south of the hotspot tracks. The segmentation of the margins offers a prime opportunity to study the magmatic signal in space and time, and investigate the interrelation with rift-related deformation. A globally significant question we address here is whether magmatism drives continental break-up, or whether even rifting accompanied by abundant magmatism is in response to crustal and lithospheric stretching governed by large-scale plate kinematics. In 2010/11, an amphibious set of wide-angle seismic data was acquired around the landfall of Walvis Ridge at the Namibian passive continental margin. The experiments were designed to provide crustal velocity information and to investigate the structure of the upper mantle. In particular, we aimed at identifying deep fault zones and variations in Moho depth, constrain the velocity signature of SDR sequences, as well as the extent of magmatic addition to the lower crust near the continent-ocean transition. Sediment cover down to the igneous basement was additionally constrained by reflection seismic data. Here, we present tomographic analysis of the seismic data of one long NNW oriented profile parallel to the continental margin across Walvis Ridge, and a second amphibious profile from the Angola Basin across Walvis Ridge and into the continental interior, crossing the area of the Etendeka Plateau basalts. The most striking feature is the sharp transition in crustal structure and thickness across the northern boundary of Walvis Ridge. Thin oceanic crust (6.5 km) of the Angola Basin lies next to the up to 35 km thick igneous crustal root founding the highest elevated northern portions of Walvis Ridge. Both structures are separated by a very large transform fault zone. The velocity structure of Walvis Ridge lower crust is indicative of gabbro, and, in the lowest parts, of cumulate sequences. On the southern side of Walvis Ridge there is a smooth gradation into the adjacent 25-30 km thick crust underlying the ocean-continent boundary, with a velocity structure resembling that of Walvis Ridge The second profile shows a sharp transition from oceanic to rifted continental crust. The transition zone may be underlain by hydrated uppermost mantle. Below the Etendeka Plateau, an extensive high-velocity body, likely representing gabbros and their cumulates at the base of the crust, indicates magmatic underplating. We summarize by stating that rift-related lithospheric stretching and associated transform faulting play an overriding role in locating magmatism, dividing the margin in a magmatic-dominated segment to the south, and an amagmatic segment north of Walvis Ridge.

Crustal architecture of the eastern margin of Japan Sea: back-arc basin opening and contraction

NASA Astrophysics Data System (ADS)

No, T.; Sato, T.; Takahashi, N.; Kodaira, S.; Kaneda, Y.; Ishiyama, T.; Sato, H.

2012-12-01

Although large earthquakes such as the 1964 Niigata earthquake (M 7.5), 1983 Nihonkai-Chubu earthquake (M 7.8), and 1993 Hokkaido Nansei-Oki earthquake (M 7.8) have caused large amounts of damage to the eastern margin of the Japan Sea, a substantial number of seismic studies have been conducted for the seismogenic zone on the Pacific Ocean side of Japan. In addition, the detail of the source fault model for the eastern margin of the Japan Sea is not well defined for all cases. This highlights the need for further studies to investigate seismic imaging. Therefore, we have collaborated with other Japanese research institutions for a project titled "Priority Investigations of Strain Concentration Areas" (which is funded by Special Coordination Funds for Promoting Science and Technology, Japan). This project has conducted seismic surveys from 2009 to 2012 using the deep-sea research vessel, Kairei, from the Japan Agency for Marine-Earth Science and Technology. There is a strain concentration area in the eastern part of the survey area (Okamura et al., 1995). The western part of the survey area includes the Yamato Basin and Japan Basin. It is very important to study the crustal structure in the seismotectonic studies of the eastern margin of the Japan Sea. We conducted a marine seismic survey by using a multichannel seismic (MCS) system and ocean bottom seismographs (OBSs) along the eastern margin of the Japan Sea. Seismic data were acquired along 42 lines with a total length of approximately 9,000 km. The following results were obtained from seismic imaging. On the basis of the results of the MCS imaging, active reverse faults and folds were observed in the margin of the Toyama Trough; however, the sedimentary layers in the trough were flat. In the sedimentary layers and crusts of the Sado Ridge, Mogami Trough, and source area of the 1964 Niigata earthquake located north of the Sado Island, greater deformation was observed. The deformation weakened toward the Yamato Basin and Japan Basin; however, the development of an asymmetric anticline and its associated reverse fault was observed off Akita prefecture, which could indicate a very recent growth structure. This development is associated with an active structure on the southern extension of the fault that caused the 1983 Nihonkai-Chubu Earthquake. On the other hand, the results from the seismic refraction/wide-angle reflection imaging using OBSs indicated that the area from the basin to the continental shelf, including the source area of the 1964 Niigata Earthquake, and the island arc crust had a large lateral variation in the upper and middle crust. In contrast, beneath the source area of the 1983 Nihonkai-Chubu Earthquake, the crustal structure is interpreted as a transitional crust between oceanic and island arc crusts, with larger variation in the P-wave velocity than those of the surrounding areas. Furthermore, the crust of the Yamato Basin area is thicker than a typical oceanic crust, whereas the crust of the Japan Basin area is similar to a typical oceanic crust.

Enhancement of the sweep efficiency of waterflooding operations by the in-situ microbial population of petroleum reservoirs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, L.R.; Vadie, A.A.; Stephens, J.O.

1995-12-31

Live cores were obtained from five reservoirs using special precautions to prevent contamination by exogenous microorganisms and minimize exposure to oxygen. The depths from which the cores were obtained ranged from 2,705 ft to 6,568 ft. Core plugs were cut radially from live cores, encased in heat-shrink plastic tubes, placed in core holders, and fitted with inlets and outlets. Nutrient additions stimulated the in-situ microbial population to increase, dissolve stratal material, produce gases, and release oil. Reduction in flow through the core plugs was observed in some cases, while in other cases flow was increased, probably due to the dissolutionmore » of carbonates in the formation. A field demonstration of the ability of the in-situ microbial population to increase oil recovery by blocking the more permeable zones of the reservoir is currently underway. This demonstration is being conducted in the North Blowhorn Creek Unit situated in Lamar County, Alabama. Live cores were obtained from a newly drilled well in the field and tested as described above. The field project involves four test patterns each including one injector, four to five producers, and a comparable control injector with its four to five producers. Nutrient injection in the field began November 1994.« less

Modelling of hydrothermal fluid flow and structural architecture in an extensional basin, Ngakuru Graben, Taupo Rift, New Zealand

NASA Astrophysics Data System (ADS)

Kissling, W. M.; Villamor, P.; Ellis, S. M.; Rae, A.

2018-05-01

Present-day geothermal activity on the margins of the Ngakuru graben and evidence of fossil hydrothermal activity in the central graben suggest that a graben-wide system of permeable intersecting faults acts as the principal conduit for fluid flow to the surface. We have developed numerical models of fluid and heat flow in a regional-scale 2-D cross-section of the Ngakuru Graben. The models incorporate simplified representations of two 'end-member' fault architectures (one symmetric at depth, the other highly asymmetric) which are consistent with the surface locations and dips of the Ngakuru graben faults. The models are used to explore controls on buoyancy-driven convective fluid flow which could explain the differences between the past and present hydrothermal systems associated with these faults. The models show that the surface flows from the faults are strongly controlled by the fault permeability, the fault system architecture and the location of the heat source with respect to the faults in the graben. In particular, fault intersections at depth allow exchange of fluid between faults, and the location of the heat source on the footwall of normal faults can facilitate upflow along those faults. These controls give rise to two distinct fluid flow regimes in the fault network. The first, a regular flow regime, is characterised by a nearly unchanging pattern of fluid flow vectors within the fault network as the fault permeability evolves. In the second, complex flow regime, the surface flows depend strongly on fault permeability, and can fluctuate in an erratic manner. The direction of flow within faults can reverse in both regimes as fault permeability changes. Both flow regimes provide insights into the differences between the present-day and fossil geothermal systems in the Ngakuru graben. Hydrothermal upflow along the Paeroa fault seems to have occurred, possibly continuously, for tens of thousands of years, while upflow in other faults in the graben has switched on and off during the same period. An asymmetric graben architecture with the Paeroa being the major boundary fault will facilitate the predominant upflow along this fault. Upflow on the axial faults is more difficult to explain with this modelling. It occurs most easily with an asymmetric graben architecture and heat sources close to the graben axis (which could be associated with remnant heat from recent eruptions from Okataina Volcanic Centre). Temporal changes in upflow can also be associated with acceleration and deceleration of fault activity if this is considered a proxy for fault permeability. Other explanations for temporal variations in hydrothermal activity not explored here are different permeability on different faults, and different permeability along fault strike.

Drastic lake level changes of Lake Van (eastern Turkey) during the past ca. 600 ka: climatic, volcanic and tectonic control

NASA Astrophysics Data System (ADS)

Cukur, D.; Krastel, S.; Schmincke, H.; Sumita, M.; Tomonaga, Y.; Damci, E.

2013-12-01

Lake Van is the largest soda lake in the world with a present surface of 3,574 km2 and a maximum water depth of 450 m. Sedimentary deposits in the lake preserve one of the most complete record of continental climate in the Middle East since the Middle Pleistocene. We studied these deposits to characterize the evolution of the lake level and its possible relationships with changes in climate, volcanic, and regional tectonics since the formation of the lake ca. 600 ka ago. Changes in lake level were determined based on high-resolution seismic reflection profiles showing erosional surfaces, changes in stratal geometries such as downward shifts in coastal onlap, and recognition of distinctive stratigraphic features such as prograding delta clinoforms. Our results show that Lake Van has undergone drastic changes in surface elevation by as much as 600 meters over the past ca. 600 ka. Five major lowstands occurred at ca. ~600 ka, ca. 365-340 ka, ca 290-230 ka; ca. 150-130 ka; and ca. 30-14 ka. During a first period (A) (ca. 600-ca 230 ka) lake levels changed drastically by hundreds of m but at longer time intervals between low and high stands. Changes occurred more frequently but mostly by a few tens of m during the past ca. 230 ka years where we can distinguish a first period (B1) of stepwise transgressions between ca. 230 and 150 ka followed by a short regression between ca. 150 and 130 ka. Lake level rose stepwise again during period B2 lasting until ca 30 ka. During the past 30 ka a regression and a final transgression each lasted ca. 15 ka years. The major lowstand periods in Lake Van occurred during glacial periods, arguing for a climatic control of these lake-level fluctuations (i.e., significantly reduced precipitation leading to lake level low stands). Although climate forcing may have been the dominant cause for the drastic lake level changes of Lake Van, volcanic and tectonic forcing factors are also invoked. For example, the number of distinct tephra layers, some several meters thick, has drastically increased in the upper ca 100 m (the past ca. 230 ka). The highest density of excellent reflectors occurs in this interval. Tectonic activity evidenced by extensional and/or compressional faults across the basin margins may have also affected the lake level fluctuations in Lake Van. This series of reconstructions using seismic stratigraphy from this study enlighten the understanding of tectonically-active lacustrine basins and provide a model for similar basins elsewhere.

Surface-geophysical characterization of ground-water systems of the Caloosahatchee River basin, southern Florida

USGS Publications Warehouse

Cunningham, Kevin J.; Locker, Stanley D.; Hine, Albert C.; Bukry, David; Barron, John A.; Guertin, Laura A.

2001-01-01

The Caloosahatchee River Basin, located in southwestern Florida, includes about 1,200 square miles of land. The Caloosahatchee River receives water from Lake Okeechobee, runoff from the watershed, and seepage from the underlying ground-water systems; the river loses water through drainage to the Gulf of Mexico and withdrawals for public-water supply and agricultural and natural needs. Water-use demands in the Caloosahatchee River Basin have increased dramatically, and the Caloosahatchee could be further stressed if river water is used to accommodate restoration of the Everglades. Water managers and planners need to know how much water will be used within the river basin and how much water is contributed by Lake Okeechobee, runoff, and ground water. In this study, marine seismic-reflection and ground-penetrating radar techniques were used as a means to evaluate the potential for flow between the river and ground-water systems. Seven test coreholes were drilled to calibrate lithostratigraphic units, their stratal geometries, and estimated hydraulic conductivities to surface-geophysical profiles. A continuous marine seismic-reflection survey was conducted over the entire length of the Caloosahatchee River and extending into San Carlos Bay. Lithostratigraphic units that intersect the river bottom and their characteristic stratal geometries were identified. Results show that subhorizontal reflections assigned to the Tamiami Formation intersect the river bottom between Moore Haven and about 9 miles westward. Oblique and sigmoidal progradational reflections assigned to the upper Peace River Formation probably crop out at the floor of the river in the Ortona area between the western side of Lake Hicpochee and La Belle. These reflections image a regional-scale progradational deltaic depositional system containing quartz sands with low to moderate estimated hydraulic conductivities. In an approximate 6-mile length of the river between La Belle and Franklin Lock, deeper karstic collapse structures are postulated. These structures influence the geometries of parallel reflections that intersect the river channel. Here, reflections assigned to the Buckingham Limestone Member of the Tamiami Formation (a confining unit) and reflections assigned to the clastic zone of the sandstone aquifer likely crop out at the river bottom. Beneath these shallow reflections, relatively higher amplitude parallel reflections of the carbonate zone of the sandstone aquifer are well displayed in the seismic-reflection profiles. In San Carlos Bay, oblique progradational reflections assigned to the upper Peace River Formation are shown beneath the bay. Almost everywhere beneath the river, a diffuse ground-water flow system is in contact with the channel bottom. Ground-penetrating radar profiles of an area about 2 miles north of the depositional axis of the deltaic depositional system in the Ortona area show that progradational clinoforms imaged on seismic reflection profiles in the Caloosahatchee River are present within about 17 feet of the ground surface. Ground-penetrating radar profiles show southward dipping, oblique progradational reflections assigned to the upper Peace River Formation that are terminated at their tops by a toplapping or erosional discontinuity. These clinoformal reflections image clean quartz sand that is probably characterized by moderate hydraulic conductivity. This sand could be mapped using ground-penetrating radar methods.

Reconstruction of the Exhumed Mantle Across the North Iberian Margin by Crustal-Scale 3-D Gravity Inversion and Geological Cross Section

NASA Astrophysics Data System (ADS)

Pedrera, A.; García-Senz, J.; Ayala, C.; Ruiz-Constán, A.; Rodríguez-Fernández, L. R.; Robador, A.; González Menéndez, L.

2017-12-01

Recent models support the view that the Pyrenees were formed after the inversion of a previously highly extended continental crust that included exhumed upper mantle rocks. Mantle rocks remain near to the surface after compression and mountain building, covered by the latest Cretaceous to Paleogene sequences. 3-D lithospheric-scale gravity inversion demands the presence of a high-density mantle body placed within the crust in order to justify the observed anomalies. Exhumed mantle, having 50 km of maximum width, continuously extends beneath the Basque-Cantabrian Basin and along the northern side of the Pyrenees. The association of this body with rift, postrift, and inversion structural geometries is tested in a balanced cross section across the Basque-Cantabrian Basin that incorporates a major south-dipping ramp-flat-ramp extensional detachment active between Valanginian and early Cenomanian times. Results indicate that horizontal extension progressed 48 km at variable strain rates that increased from 1 to 4 mm/yr in middle Albian times. Low-strength Triassic Keuper evaporites and mudstones above the basement favor the decoupling of the cover with formation of minibasins, expulsion rollovers, and diapirs. The inversion of the extensional system is accommodated by doubly verging basement thrusts due to the reactivation of the former basin bounding faults in Eocene-Oligocene times. Total shortening is estimated in 34 km and produced the partial subduction of the continental lithosphere beneath the two sides of the exhumed mantle. Obtained results help to pinpoint the original architecture of the North Iberian Margin and the evolution of the hyperextended aborted intracontinental basins.

Crustal structure and evolution of the Pyrenean-Cantabrian belt: A review and new interpretations from recent concepts and data

NASA Astrophysics Data System (ADS)

Teixell, A.; Labaume, P.; Ayarza, P.; Espurt, N.; de Saint Blanquat, M.; Lagabrielle, Y.

2018-01-01

This paper provides a synthesis of current data and interpretations on the crustal structure of the Pyrenean-Cantabrian orogenic belt, and presents new tectonic models for representative transects. The Pyrenean orogeny lasted from Santonian ( 84 Ma) to early Miocene times ( 20 Ma), and consisted of a spatial and temporal succession of oceanic crust/exhumed mantle subduction, rift inversion and continental collision processes at the Iberia-Eurasia plate boundary. A good coverage by active-source (vertical-incidence and wide-angle reflection) and passive-source (receiver functions) seismic studies, coupled with surface data have led to a reasonable knowledge of the present-day crustal architecture of the Pyrenean-Cantabrian belt, although questions remain. Seismic imaging reveals a persistent structure, from the central Pyrenees to the central Cantabrian Mountains, consisting of a wedge of Eurasian lithosphere indented into the thicker Iberian plate, whose lower crust is detached and plunges northwards into the mantle. For the Pyrenees, a new scheme of relationships between the southern upper crustal thrust sheets and the Axial Zone is here proposed. For the Cantabrian belt, the depth reached by the N-dipping Iberian crust and the structure of the margin are also revised. The common occurrence of lherzolite bodies in the northern Pyrenees and the seismic velocity and potential field record of the Bay of Biscay indicate that the precursor of the Pyrenees was a hyperextended and strongly segmented rift system, where narrow domains of exhumed mantle separated the thinned Iberian and Eurasian continental margins since the Albian-Cenomanian. The exhumed mantle in the Pyrenean rift was largely covered by a Mesozoic sedimentary lid that had locally glided along detachments in Triassic evaporites. Continental margin collision in the Pyrenees was preceded by subduction of the exhumed mantle, accompanied by the pop-up thrust expulsion of the off-scraped sedimentary lid above. To the west, oceanic subduction of the Bay of Biscay under the North Iberian margin is supported by an upper plate thrust wedge, gravity and magnetic anomalies, and 3D inclined sub-crustal reflections. However, discrepancies remain for the location of continent-ocean transitions in the Bay of Biscay and for the extent of oceanic subduction. The plate-kinematic evolution during the Mesozoic, which involves issues as the timing and total amount of opening, as well as the role of strike-slip drift, is also under debate, discrepancies arising from first-order interpretations of the adjacent oceanic magnetic anomaly record.

Recent Aeromagnetic Anomaly views of the Antarctic continent

NASA Astrophysics Data System (ADS)

Ferraccioli, F.

2012-04-01

Antarctica is a keystone within the Gondwana and Rodinia supercontinents. However, despite intense geological research along the coastal fringes of Antarctica, the interior of the continent remains one of the most poorly understood regions on Earth. Aeromagnetic investigations are a useful tool to help disclose the structure and the evolution of continents from the Precambrian to the Cenozoic and Antarctica is no exception. Here I review a variety of aeromagnetic studies in East and West Antarctica performed since the completion of the first generation ADMAP -Antarctic Digital Magnetic Anomaly Project- in 2001. In western Dronning Maud, in East Antarctica, aeromagnetic data help delineate the extent of the Jurassic Jutulstraumen subglacial rift that is flanked by remnants of a Grenvillian-age (ca 1.1. Ga) igneous province and magmatic arc. Different magnetic signatures appear to characterize the Coats Land block but reconnaissance surveys are insufficient to fully delineate the extent and significance of the Coats Land block, a possible tectonic tracer of Laurentia within Rodinia (Loewy et al., 2011). Further in the interior of East Antarctica, a mosaic of distinct and hitherto largely unknown Precambrian provinces has recently been revealed by combining aeromagnetic and satellite magnetic data with models of crustal thickness constrained by gravity modeling and seismology (Ferraccioli et al., 2011, Nature). A major collisional suture may lie between the Archean Ruker Province and an inferred Proterozoic Gamburtsev Province but the age of final assembly of central East Antarctica remains uncertain and controversial. I favour a Grenville-age collisional event (linked to Rodinia assembly) or possibly older Paleoproteroic collision, followed by intraplate reactivation, as opposed to Neoproterozoic or Early Cambrian collision linked to East-West Gondwana assembly (Boger, 2011). New aerogeophysical surveys over Prince Elizabeth and Queen Mary Land could test this hypothesis further and contribute towards understanding the role that the inherited Precambrian architecture exerted on the location and development of the East Antarctic Rift System, which was active both before and during Gondwana break-up. Over Wilkes Land, aeromagnetic data offer tantalizing new glimpses into the extent of Precambrian basement provinces that have been extensively studied in formerly adjacent Australia. An over 1,900 km long magnetic low is traced from a new magnetic anomaly compilation along the margin of the Archean-Proterozoic Mawson continent, and is interpreted as delineating part of a Neoproterozoic rift system that heralded Rodinia break-up. Aeromagnetic data are also helping in deciphering Phanerozoic crustal growth along the paleo-Pacific active margin of Gondwana. In northern Victoria Land aeromagnetic anomaly interpretation, coupled with geochemical and structural observations is clarifying the architecture and evolution of Cambro-Ordovician terranes that were affected by the Ross Orogen. In the Antarctic Peninsula aeromagnetic and aerogravity data suggest the existence of several distinct arc provinces that may have docked against the Gondwana margin during the Cretaceous age Palmer Land event. Aeromagnetic interpretation over the West Antarctic ice sheet provides new insights into the extent of Cenozoic magmatism and rift basins within the West Antarctic Rift System and into the inland extent of the Jurassic Weddell Sea Rift

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rush, Jason; Holubnyak, Yevhen; Watney, Willard

This DOE-funded project evaluates the utility of seismic volumetric curvature (VC) for predicting stratal and structural architecture diagnostic of paleokarst reservoirs. Of special interest are applications geared toward carbon capture, utilization, and storage (CCUS). VC has been championed for identifying faults (offset <¼ λ) that cannot be imaged by conventional 3-D seismic attributes such as coherence. The objective of this research was to evaluate VC-techniques for reducing uncertainties in reservoir compartmentalization studies and seal risk assessments especially for saline aquifers. A 2000-ft horizontal lateral was purposefully drilled across VC-imaged lineaments—interpreted to record a fractured and a fault-bounded doline—to physically confirmmore » their presence. The 15-mi² study area is located in southeastern Bemis-Shutts Field, which is situated along the crest of the Central Kansas Uplift (CKU) in Ellis County, Kansas. The uppermost Arbuckle (200+ ft) has extensive paleokarst including collapsed paleocaverns and dolines related to exceedingly prolonged pre-Simpson (Sauk–Tippecanoe) and/or pre-Pennsylvanian subaerial exposure. A lateral borehole was successfully drilled across the full extent (~1100 ft) of a VC-inferred paleokarst doline. Triple combo (GR-neutron/density-resistivity), full-wave sonic, and borehole micro-imager logs were successfully run to TD on drill-pipe. Results from the formation evaluation reveal breccias (e.g., crackle, mosaic, chaotic), fractures, faults, vugs (1-6"), and unaffected host strata consistent with the pre-spud interpretation. Well-rounded pebbles were also observed on the image log. VC-inferred lineaments coincide with 20–80-ft wide intervals of high GR values (100+ API), matrix-rich breccias, and faults. To further demonstrate their utility, VC attributes are integrated into a geocellular modeling workflow: 1) to constrain the structural model; 2) to generate facies probability grids, and; 3) to collocate petrophysical models to separate-vug rock fabrics along solution-enlarged fault and fracture systems. Simulation-based studies demonstrate a potential alternative field development model for developing CO 2 storage sites that target carbonate reservoirs overprinted by paleokarst. Simulation results for this complex reservoir indicate that individual fault blocks could function as discrete containers for CO 2 storage thereby reducing the risk of plume migration outside the legally defined extent of the permitted storage site. Vertically extensive, anastomosing, solution-enlarged fault/fracture systems — infilled by clay-rich sediments — would operate as non-to-low permeability vertical "curtains" that restrict CO 2 movement beyond the confines of the CO 2 storage site. Such a location could be developed in a checker-board fashion with CO 2 injection operations occurring in one block and surveillance operations occurring in the adjacent block. Such naturally partitioned reservoirs may be ideal candidates for reducing risks associated with CO 2 plume breakthrough.« less

Near N-S paleo-extension in the western Deccan region, India: Does it link strike-slip tectonics with India-Seychelles rifting?

NASA Astrophysics Data System (ADS)

Misra, Achyuta Ayan; Bhattacharya, Gourab; Mukherjee, Soumyajit; Bose, Narayan

2014-09-01

This is the first detailed report and analyses of deformation from the W part of the Deccan large igneous province (DLIP), Maharashtra, India. This deformation, related to the India-Seychelles rifting during Late Cretaceous-Early Paleocene, was studied, and the paleostress tensors were deduced. Near N-S trending shear zones, lineaments, and faults were already reported without significant detail. An E-W extension was envisaged by the previous workers to explain the India-Seychelles rift at ~64 Ma. The direction of extension, however, does not match with their N-S brittle shear zones and also those faults (sub-vertical, ~NE-SW/~NW-SE, and few ~N-S) we report and emphasize in this work. Slickenside-bearing fault planes, brittle shear zones, and extension fractures in meso-scale enabled us to estimate the paleostress tensors (directions and relative magnitudes). The field study was complemented by remote sensing lineament analyses to map dykes and shear zones. Dykes emplaced along pre-existing ~N-S to ~NE-SW/~NW-SE shears/fractures. This information was used to derive regional paleostress trends. A ~NW-SE/NE-SW minimum compressive stress in the oldest Kalsubai Subgroup and a ~N-S direction for the younger Lonavala, Wai, and Salsette Subgroups were deciphered. Thus, a ~NW/NE to ~N-S extension is put forward that refutes the popular view of E-W India-Seychelles extension. Paleostress analyses indicate that this is an oblique rifted margin. Field criteria suggest only ~NE-SW and ~NW-SE, with some ~N-S strike-slip faults/brittle shear zones. We refer this deformation zone as the "Western Deccan Strike-slip Zone" (WDSZ). The observed deformation was matched with offshore tectonics deciphered mainly from faults interpreted on seismic profiles and from magnetic seafloor spreading anomalies. These geophysical findings too indicate oblique rifting in this part of the W Indian passive margin. We argue that the Seychelles microcontinent separated from India only after much of the DLIP erupted. Further studies of magma-rich passive margins with respect to timing and architecture of deformation and emplacement of volcanics are required.

Marginal zone lymphoma-derived interfollicular diffuse large B-cell lymphoma harboring 20q12 chromosomal deletion and missense mutation of BIRC3 gene: a case report.

PubMed

Hatem, Joseph; Schrank-Hacker, April M; Watt, Christopher D; Morrissette, Jennifer J D; Rubin, Adam I; Kim, Ellen J; Nasta, Sunita D; Wasik, Mariusz A; Bogusz, Agata M

2016-12-19

Diffuse large B-cell lymphoma (DLBCL) typically leads to effacement of the nodal architecture by an infiltrate of malignant cells. Rarely (<1%), DLBCL can present with an interfollicular pattern (DLBCL-IF) preserving the lymphoid follicles. It has been postulated that DLBCL-IF is derived from marginal zone B cells and may represent a large-cell transformation of marginal zone lymphoma (MZL), however no direct evidence has been provided to date. Here we describe a rare case of a diagnostically challenging DLBCL-IF involving a lymph node in a patient with a prior history of lymphadenopathy for several years and MZL involving skin. A 53-year old man presented to our Dermatology Clinic due to a 1-year history of generalized itching, fatigue of 2-3 month's duration, nausea and mid back rash that was biopsied. PET (positron emission tomography)/CT (computed tomography) was performed and revealed inguinal, pelvic, retroperitoneal, axillary, and cervical lymphadenopathy. The patient was referred to surgery for excisional biopsy of a right inguinal lymph node. Diagnostic H&E stained slides and ancillary studies were reviewed for the lymph node and skin specimens. B-cell clonality by PCR and sequencing studies were performed on both specimens. We demonstrate that this patient's MZL and DLBCL-IF are clonally related, strongly suggesting that transformation of MZL to DLBCL had occurred. Furthermore, we identified a novel deletion of the long arm of chromosome 20 (del(20q12)) and a missense mutation in BIRC3 (Baculoviral IAP repeat-containing protein 3) in this patient's DLBCL that are absent from his MZL, suggesting that these genetic alterations contributed to the large cell transformation. To our knowledge, this is the first report providing molecular evidence for a previously suspected link between MZL and DLBCL-IF. In addition, we describe for the first time del(20q12) and a missense mutation in BIRC3 in DLBCL. Our findings also raise awareness of DLBCL-IF and discuss the diagnostic pitfalls of this rare entity.

Late Cenozoic extensional faulting in Central-Western Peloponnesus, Greece

NASA Astrophysics Data System (ADS)

Skourtsos, E.; Fountoulis, I.; Mavroulis, S.; Kranis, H.

2012-04-01

A series of forearc-dipping, orogen-parallel extensional faults are found in the central-western Peloponnesus, (south-western Aegean) which control the western margin of Mt Mainalon. The latter comprises HP/LT rocks of the Phyllites-Quartzites Unit (PQ), overlain by the carbonates and flysch of the Tripolis Unit while the uppermost nappe is the Pindos Unit, a sequence of Mesozoic pelagic sequence, topped by a Paleocene flysch. Most of the extensional structures were previously thought of as the original thrust between the Pindos and Tripolis Units. However, the cross-cutting relationships among these structures indicate that these are forearc (SW-dipping) extensional faults, downthrowing the Pindos thrust by a few tens or hundreds of meters each, rooting onto different levels of the nappe pile. In SW Mainalon the lowermost of the extensional faults is a low-angle normal fault dipping SW juxtaposing the metamorphic rocks of the PQ Unit against the non-metamorphic sequence of the Tripolis Unit. High-angle normal faults, found further to the west, have truncated or even sole onto the low-angle ones and control the eastern margin of the Quaternary Megalopolis basin. All these extensional structures form the eastern boundary of a series of Neogene-Quaternary tectonic depressions, which in turn are separated by E-W horsts. In the NW, these faults are truncated by NE to NNE-striking, NW-dipping faults, which relay the whole fault activity to the eastern margin of the Pyrgos graben. The whole extensional fault architecture has resulted (i) in the Pindos thrust stepping down from altitudes higher than 1000 m in Mainalon in the east, to negative heights in North Messinia and Southern Ilia in the west; and (ii) the gradual disappearance of the Phyllite-Quartzite metamorphics of Mainalon towards the west. The combination of these extensional faults (which may reach down to the Ionian décollement) with the low-angle floor thrusts of the Pindos, Tripolis and Ionian Units leads to additional ENE-WSW shortening, normal to the Hellenic Arc, west of the Peloponnesus.

Episodic Sediment Failure in Northern Flemish Pass, Eastern Canadian Margin: Interplay of Seismicity, Contour Current Winnowing, and Excess Pore Pressures

NASA Astrophysics Data System (ADS)

Piper, D.

2015-12-01

Episodic sediment failures are recognised on continental slopes around Flemish Pass and Orphan Basin from multibeam bathymetry, seismic reflection profiles and piston cores. Seismic stratigraphy is tied to published long cores with O-isotope data back to before MIS 6 and carbonate rich Heinrich layers in places produce marker reflections in high-resolution sparker profiles. Heinrich layers, radiocarbon dates and peaks in diatom abundance provide core chronology. Slope sedimentation was strongly influenced by the Labrador Current and the silty muds show architecture characteristic of contourites. Variation in Labrador Current strength is known from the sortable silt proxy over the past 125 ka. Large slope failures were mapped from seismic reflection profiles and their age estimated from seismic stratigraphy (3-5 ka resolution) and in some cases refined from cores (1-3 ka resolution). Large slope failures occurred apparently synchronously over margin lengths of 50-350 km. Such failures were earthquake triggered: other mechanisms for producing laterally extensive synchronous failure do not apply. Triaxial shear measurements show a Su/σ' ratio of typical slope sediment of 0.48, implying considerable stability. However, some silty muds have Atterberg limits that suggest susceptibility to liquefaction under cyclic loading, particularly in Holocene deposits and by analogy those of past full interglacials. Basal failure planes of some large failures correspond with either the last interglacial or the MIS 6 glacial maximum. Comparison with seismological models suggests that the observed slope failures represent earthquakes ranging from Mw ~5.6 to ~7.6. Mean recurrence interval of M = 7 earthquakes at any point on the margin is estimated at 30 ka from seismological models and 40 ka from the sediment failure record. In northern Flemish Pass, a spatial cluster of several failures over 30 ka preceded by a long interval with no failures suggests that some other mechanism has preconditioned the slope for earthquake triggering. There is circumstantial evidence that such preconditioning is related to excess pore pressures, released by fluid drainage at head scarps.

Structure of the Lithosphere-Asthenosphere Boundary Onshore and Offshore the California Continental Margin from Three-Dimensional Seismic Anisotropy

NASA Astrophysics Data System (ADS)

Gomez, C. D.; Escobar, L., Sr.; Rathnayaka, S.; Weeraratne, D. S.; Kohler, M. D.

2016-12-01

The California continental margin, a major transform plate boundary in continental North America, is the locus of complex tectonic stress fields that are important in interpreting both remnant and ongoing deformational strain. Ancient subduction of the East Pacific Rise spreading center, the rotation and translation of tectonic blocks and inception of the San Andreas fault all contribute to the dynamic stress fields located both onshore and offshore southern California. Data obtained by the ALBACORE (Asthenospheric and Lithospheric Broadband Architecture from the California Offshore Region Experiment) and the CISN (California Integrated Seismic Network) seismic array are analyzed for azimuthal anisotropy of Rayleigh waves from 80 teleseismic events at periods 16 - 78 s. Here we invert Rayleigh wave data for shear wave velocity structure and three-dimensional seismic anisotropy in the thee regions designated within the continental margin including the continent, seafloor and California Borderlands. Preliminary results show that seismic anisotropy is resolved in multiple layers and can be used to determine the lithosphere-asthenosphere boundary (LAB) in offshore and continental regions. The oldest seafloor in our study at age 25-35 Ma indicates that the anisotropic transition across the LAB occurs at 73 km +/- 25 km with the lithospheric fast direction oriented WNW-ESE, consistent with current Pacific plate motion direction. The continent region west of the San Andreas indicates similar WNW-ESE anisotropy and LAB depth. Regions east of the San Andreas fault indicate NW-SE anisotropy transitioning to a N-S alignment at 80 km depth north of the Garlock fault. The youngest seafloor (15 - 25 Ma) and outer Borderlands indicate a more complex three layer fabric where shallow lithospheric NE-SW fast directions are perpendicular with ancient Farallon subduction arc, a mid-layer with E-W fast directions are perpendicular to remnant fossil fabric, and the deepest layer indicates NW-SE fast directions below the LAB likely controlled by current Pacific plate motion. The inner Borderland indicates two layer anisotropic structure with a shallow NW-SE lithospheric fast direction that changes to NE-SW fast directions below the LAB, possibly consistent with the ancient subduction direction.

A Simple and Computationally Efficient Sampling Approach to Covariate Adjustment for Multifactor Dimensionality Reduction Analysis of Epistasis

PubMed Central

Gui, Jiang; Andrew, Angeline S.; Andrews, Peter; Nelson, Heather M.; Kelsey, Karl T.; Karagas, Margaret R.; Moore, Jason H.

2010-01-01

Epistasis or gene-gene interaction is a fundamental component of the genetic architecture of complex traits such as disease susceptibility. Multifactor dimensionality reduction (MDR) was developed as a nonparametric and model-free method to detect epistasis when there are no significant marginal genetic effects. However, in many studies of complex disease, other covariates like age of onset and smoking status could have a strong main effect and may potentially interfere with MDR's ability to achieve its goal. In this paper, we present a simple and computationally efficient sampling method to adjust for covariate effects in MDR. We use simulation to show that after adjustment, MDR has sufficient power to detect true gene-gene interactions. We also compare our method with the state-of-art technique in covariate adjustment. The results suggest that our proposed method performs similarly, but is more computationally efficient. We then apply this new method to an analysis of a population-based bladder cancer study in New Hampshire. PMID:20924193

Chinese Sentence Classification Based on Convolutional Neural Network

NASA Astrophysics Data System (ADS)

Gu, Chengwei; Wu, Ming; Zhang, Chuang

2017-10-01

Sentence classification is one of the significant issues in Natural Language Processing (NLP). Feature extraction is often regarded as the key point for natural language processing. Traditional ways based on machine learning can not take high level features into consideration, such as Naive Bayesian Model. The neural network for sentence classification can make use of contextual information to achieve greater results in sentence classification tasks. In this paper, we focus on classifying Chinese sentences. And the most important is that we post a novel architecture of Convolutional Neural Network (CNN) to apply on Chinese sentence classification. In particular, most of the previous methods often use softmax classifier for prediction, we embed a linear support vector machine to substitute softmax in the deep neural network model, minimizing a margin-based loss to get a better result. And we use tanh as an activation function, instead of ReLU. The CNN model improve the result of Chinese sentence classification tasks. Experimental results on the Chinese news title database validate the effectiveness of our model.

Miocene Lonchocarpus (Papilionoideae) in San Esteban Tizatlán, Tlaxcala, Mexico

NASA Astrophysics Data System (ADS)

Hernández-Damián, Ana Lilia; Calvillo-Canadell, Laura; Cevallos-Ferriz, Sergio R. S.; Sousa, Mario

2016-03-01

New leaflets from San Esteban Tizatlán, Tlaxcala, Mexico, are described and identified based on their leaf architecture. They have elliptic leaflets with pulvinate petiolule, entire margin, convex apex and base, well developed primary and craspedodromous secondary venation, with decurrent secondary veins with fused the mid-vein, a pair of obtuse basal veins, weak intersecundary veins, mixed percurrent tertiary venation dominated by the opposite type with sinuous course, alternate percurrent fourth-order venation, regular reticulate with few non ramified veinlets. All these characteristics are closely compared with members of sections Obtusifolii and Standleyi of Lonchocarpus (Leguminosae, Papillionoideae, Millettieae), but the mosaic of characters found in the fossil material granted recognition of a new species Lonchocarpus miocenicus sp. nov. This new record of Lonchocarpus from central Mexico further supports the presence of an evergreen tropical forest during the Miocene in the area, a plant community that developed from the Boreotropical Flora and contributed latter to the Neotropical Flora.

Flight Control Laws for NASA's Hyper-X Research Vehicle

NASA Technical Reports Server (NTRS)

Davidson, J.; Lallman, F.; McMinn, J. D.; Martin, J.; Pahle, J.; Stephenson, M.; Selmon, J.; Bose, D.

1999-01-01

The goal of the Hyper-X program is to demonstrate and validate technology for design and performance predictions of hypersonic aircraft with an airframe-integrated supersonic-combustion ramjet propulsion system. Accomplishing this goal requires flight demonstration of a hydrogen-fueled scramjet powered hypersonic aircraft. A key enabling technology for this flight demonstration is flight controls. Closed-loop flight control is required to enable a successful stage separation, to achieve and maintain the design condition during the engine test, and to provide a controlled descent. Before the contract award, NASA developed preliminary flight control laws for the Hyper-X to evaluate the feasibility of the proposed scramjet test sequence and descent trajectory. After the contract award, a Boeing/NASA partnership worked to develop the current control laws. This paper presents a description of the Hyper-X Research Vehicle control law architectures with performance and robustness analyses. Assessments of simulated flight trajectories and stability margin analyses demonstrate that these control laws meet the flight test requirements.

The vacuole system is a significant intracellular pathway for longitudinal solute transport in basidiomycete fungi.

PubMed

Darrah, P R; Tlalka, M; Ashford, A; Watkinson, S C; Fricker, M D

2006-07-01

Mycelial fungi have a growth form which is unique among multicellular organisms. The data presented here suggest that they have developed a unique solution to internal solute translocation involving a complex, extended vacuole. In all filamentous fungi examined, this extended vacuole forms an interconnected network, dynamically linked by tubules, which has been hypothesized to act as an internal distribution system. We have tested this hypothesis directly by quantifying solute movement within the organelle by photobleaching a fluorescent vacuolar marker. Predictive simulation models were then used to determine the transport characteristics over extended length scales. This modeling showed that the vacuolar organelle forms a functionally important, bidirectional diffusive transport pathway over distances of millimeters to centimeters. Flux through the pathway is regulated by the dynamic tubular connections involving homotypic fusion and fission. There is also a strongly predicted interaction among vacuolar organization, predicted diffusion transport distances, and the architecture of the branching colony margin.

Guidance, Navigation and Control (GN&C): Best Practices for Human-Rated Spacecraft Systems

NASA Technical Reports Server (NTRS)

Lebsock, Ken; West, John

2008-01-01

In 2007 the NESC completed an in-depth assessment to identify, define and document engineering considerations for the Design Development Test and Evaluation (DDT&E) of human-rated spacecraft systems. This study had been requested by the Astronaut Office at JSC to help them to better understand what is required to ensure safe, robust, and reliable human-rated spacecraft systems. The 22 GN&C engineering Best Practices described in this paper are a condensed version of what appears in the NESC Technical Report. These Best Practices cover a broad range from fundamental system architectural considerations to more specific aspects (e.g., stability margin recommendations) of GN&C system design and development. 15 of the Best Practices address the early phases of a GN&C System development project and the remaining 7 deal with the later phases. Some of these Best Practices will cross-over between both phases. We recognize that this set of GN&C Best Practices will not be universally applicable to all projects and mission applications.

[Gastric MALT-type lymphoma. Pathology, pathogenesis, diagnostics and therapy].

PubMed

Eck, M; Fischbach, W

2010-05-01

Helicobacter pylori infection plays a central role in the development of gastric MALT-type (mucosa-associated lymphoid tissue) lymphoma. Infection results in chronic H. pylori gastritis and stimulates together with antigens or autoantigens proliferation of B-lymphocytes which is the basis for the neoplastic transformation. Histology of MALT-type lymphoma is architecturally similar to the physiological MALT. Invasion and destruction of the gastric epithelium with development of so-called lympho-epithelial lesions is the most important diagnostic criterion. Cytologically MALT-lymphoma resembles centrocytes and monocytes. For definitive lymphoma diagnosis and for the differential diagnosis from other small cell lymphomas in the stomach immunohistochemistry can be helpful. The phenotype of MALT-type lymphoma is identical to non-neoplastic B-lymphocytes of the marginal zone (CD20+, CD5-, CD10- and CD23-). Individual therapy is strongly dependent from histological type and lymphoma stadium. Therapy modalities are H. pylori eradication, radiochemotherapy, surgery or a combination of these. Aim of the therapy is the complete lymphoma regression and cure of the disease.

Cryptic Genetic Variation for Arabidopsis thaliana Seed Germination Speed in a Novel Salt Stress Environment

PubMed Central

Yuan, Wei; Flowers, Jonathan M.; Sahraie, Dustin J.; Purugganan, Michael D.

2016-01-01

The expansion of species ranges frequently necessitates responses to novel environments. In plants, the ability of seeds to disperse to marginal areas relies in part to its ability to germinate under stressful conditions. Here we examine the genetic architecture of Arabidopsis thaliana germination speed under a novel, saline environment, using an Extreme QTL (X-QTL) mapping platform we previously developed. We find that early germination in normal and salt conditions both rely on a QTL on the distal arm of chromosome 4, but we also find unique QTL on chromosomes 1, 2, 4, and 5 that are specific to salt stress environments. Moreover, different QTLs are responsible for early vs. late germination, suggesting a temporal component to the expression of life history under these stress conditions. Our results indicate that cryptic genetic variation exists for responses to a novel abiotic stress, which may suggest a role of such variation in adaptation to new climactic conditions or growth environments. PMID:27543295

X-38 Experimental Controls Laws

NASA Technical Reports Server (NTRS)

Munday, Steve; Estes, Jay; Bordano, Aldo J.

2000-01-01

X-38 Experimental Control Laws X-38 is a NASA JSC/DFRC experimental flight test program developing a series of prototypes for an International Space Station (ISS) Crew Return Vehicle, often called an ISS "lifeboat." X- 38 Vehicle 132 Free Flight 3, currently scheduled for the end of this month, will be the first flight test of a modem FCS architecture called Multi-Application Control-Honeywell (MACH), originally developed by the Honeywell Technology Center. MACH wraps classical P&I outer attitude loops around a modem dynamic inversion attitude rate loop. The dynamic inversion process requires that the flight computer have an onboard aircraft model of expected vehicle dynamics based upon the aerodynamic database. Dynamic inversion is computationally intensive, so some timing modifications were made to implement MACH on the slower flight computers of the subsonic test vehicles. In addition to linear stability margin analyses and high fidelity 6-DOF simulation, hardware-in-the-loop testing is used to verify the implementation of MACH and its robustness to aerodynamic and environmental uncertainties and disturbances.

Final implementation, commissioning, and performance of embedded collimator beam position monitors in the Large Hadron Collider

NASA Astrophysics Data System (ADS)

Valentino, Gianluca; Baud, Guillaume; Bruce, Roderik; Gasior, Marek; Mereghetti, Alessio; Mirarchi, Daniele; Olexa, Jakub; Redaelli, Stefano; Salvachua, Belen; Valloni, Alessandra; Wenninger, Jorg

2017-08-01

During Long Shutdown 1, 18 Large Hadron Collider (LHC) collimators were replaced with a new design, in which beam position monitor (BPM) pick-up buttons are embedded in the collimator jaws. The BPMs provide a direct measurement of the beam orbit at the collimators, and therefore can be used to align the collimators more quickly than using the standard technique which relies on feedback from beam losses. Online orbit measurements also allow for reducing operational margins in the collimation hierarchy placed specifically to cater for unknown orbit drifts, therefore decreasing the β* and increasing the luminosity reach of the LHC. In this paper, the results from the commissioning of the embedded BPMs in the LHC are presented. The data acquisition and control software architectures are reviewed. A comparison with the standard alignment technique is provided, together with a fill-to-fill analysis of the measured orbit in different machine modes, which will also be used to determine suitable beam interlocks for a tighter collimation hierarchy.

Extreme Mesozoic crustal thinning in the Eastern Iberia margin: The example of the Columbrets Basin (Valencia Trough)

NASA Astrophysics Data System (ADS)

Mohn, G.; Etheve, N.; Frizon de Lamotte, D.; Roca, E.; Tugend, J.; Gómez-Romeu, J.

2017-12-01

Eastern Iberia preserves a complex succession of Mesozoic rifts partly or completely inverted during the Late Cretaceous and Cenozoic in relation with Africa-Eurasia convergence. Notably, the Valencia Trough, classically viewed as part of the Cenozoic West Mediterranean basins, preserves in its southwestern part a thick Mesozoic succession (locally »10km thick) over a highly thinned continental basement (locally only »3,5km thick). This sub-basin referred to as the Columbrets Basin, represents a Late Jurassic-Early Cretaceous hyper-extended rift basin weakly overprinted by subsequent events. Its initial configuration is well preserved allowing us to unravel its 3D architecture and tectono-stratigraphic evolution in the frame of the Mesozoic evolution of eastern Iberia. The Columbrets Basin benefits from an extensive dataset combining high resolution reflection seismic profiles, drill holes, refraction seismic data and Expanding Spread Profiles. Its Mesozoic architecture is controlled by interactions between extensional deformation and halokinesis involving the Upper Triassic salt. The thick uppermost Triassic to Cretaceous succession describes a general synclinal shape, progressively stretched and dismembered towards the basin borders. The SE-border of the basin is characterized by a large extensional detachment fault acting at crustal scale and interacting locally with the Upper Triassic décollement. This extensional structure accommodates the exhumation of the continental basement and part of the crustal thinning. Eventually our results highlight the complex interaction between extreme crustal thinning and occurrence of a pre-rift salt level for the deformation style and tectono-stratigraphic evolution of hyper-extended rift basins.

Development of reservoir facies and porosity-permeability compartmentalization in middle Mississippian Salem Limestone, eastern margin of the Illinois Basin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ahmad, N.; Keith, B.D.; Thompson, T.A.

Shoal facies of the Salem Limestone in south-central Indiana are composed of (1) bryozoan- and echinoderm-rich (85-95%) grainstones, and (3) foraminiferal-echinodermal grainstones. Microfacies and bedform analyses indicate that deposition took place under tidal conditions where sporadic storm events mobilized the entire sand body. Strong, primarily unidirectional currents, abundant sediment supply, and rapid burial resulted in thick, massive deposits in the Salem shoal. In this hydraulic regime, shape and specific gravity determined the distribution of echinoderm grains relative to heavier bryozoan grains. The relative amount of echinoderms controlled the development of early syntaxial rim cement, which preserved porosity during early compaction.more » A significant amount of calcium carbonate ({approximately}58%) filled the micropores within the echinoderm grains before the intergranular cement could form. Areas such as toes of avalanche forests, where intermediate amounts of echinoderms are mixed with other grains, have greater porosity and permeability. Numerous stylolites also occur throughout the Salem grainstones. Variations in microfacies composition and bedforms are grouped into architectural packages that compartmentalize the porosity and permeability and form micro-to scale macroscale heterogeneities. The basal channel architectural package studied exhibits porosity-permeability compartments orthogonal to the overlying channel-fill sandwave package. In an analogous petroleum reservoir this can result in poor reservoir performance during primary and enhanced recovery leaving behind significant amounts of unrecovered mobile oil. Higher porosity and permeability at the base of a package due to the presence of toesets of a certain grain composition can result in poor sweep efficiency for enhanced recovery.« less

Newly identified helper bacteria stimulate ectomycorrhizal formation in Populus.

PubMed

Labbé, Jessy L; Weston, David J; Dunkirk, Nora; Pelletier, Dale A; Tuskan, Gerald A

2014-01-01

Mycorrhiza helper bacteria (MHB) are known to increase host root colonization by mycorrhizal fungi but the molecular mechanisms and potential tripartite interactions are poorly understood. Through an effort to study Populus microbiome, we isolated 21 Pseudomonas strains from native Populus deltoides roots. These bacterial isolates were characterized and screened for MHB effectiveness on the Populus-Laccaria system. Two additional Pseudomonas strains (i.e., Pf-5 and BBc6R8) from existing collections were included for comparative purposes. We analyzed the effect of co-cultivation of these 23 individual Pseudomonas strains on Laccaria bicolor "S238N" growth rate, mycelial architecture and transcriptional changes. Nineteen of the 23 Pseudomonas strains tested had positive effects on L. bicolor S238N growth, as well as on mycelial architecture, with strains GM41 and GM18 having the most significant effect. Four of seven L. bicolor reporter genes, Tra1, Tectonin2, Gcn5, and Cipc1, thought to be regulated during the interaction with MHB strain BBc6R8, were induced or repressed, while interacting with Pseudomonas strains GM17, GM33, GM41, GM48, Pf-5, and BBc6R8. Strain GM41 promoted the highest roots colonization across three Populus species but most notably in P. deltoides, which is otherwise poorly colonized by L. bicolor. Here we report novel MHB strains isolated from native Populus that improve L. bicolor root colonization on Populus. This tripartite relationship could be exploited for Populus species/genotypes nursery production as a means of improving establishment and survival in marginal lands.

Newly identified helper bacteria stimulate ectomycorrhizal formation in Populus

PubMed Central

Labbé, Jessy L.; Weston, David J.; Dunkirk, Nora; Pelletier, Dale A.; Tuskan, Gerald A.

2014-01-01

Mycorrhiza helper bacteria (MHB) are known to increase host root colonization by mycorrhizal fungi but the molecular mechanisms and potential tripartite interactions are poorly understood. Through an effort to study Populus microbiome, we isolated 21 Pseudomonas strains from native Populus deltoides roots. These bacterial isolates were characterized and screened for MHB effectiveness on the Populus-Laccaria system. Two additional Pseudomonas strains (i.e., Pf-5 and BBc6R8) from existing collections were included for comparative purposes. We analyzed the effect of co-cultivation of these 23 individual Pseudomonas strains on Laccaria bicolor “S238N” growth rate, mycelial architecture and transcriptional changes. Nineteen of the 23 Pseudomonas strains tested had positive effects on L. bicolor S238N growth, as well as on mycelial architecture, with strains GM41 and GM18 having the most significant effect. Four of seven L. bicolor reporter genes, Tra1, Tectonin2, Gcn5, and Cipc1, thought to be regulated during the interaction with MHB strain BBc6R8, were induced or repressed, while interacting with Pseudomonas strains GM17, GM33, GM41, GM48, Pf-5, and BBc6R8. Strain GM41 promoted the highest roots colonization across three Populus species but most notably in P. deltoides, which is otherwise poorly colonized by L. bicolor. Here we report novel MHB strains isolated from native Populus that improve L. bicolor root colonization on Populus. This tripartite relationship could be exploited for Populus species/genotypes nursery production as a means of improving establishment and survival in marginal lands. PMID:25386184

From Hippocampus to Whole-Brain: The Role of Integrative Processing in Episodic Memory Retrieval

PubMed Central

Geib, Benjamin R.; Stanley, Matthew L.; Dennis, Nancy A.; Woldorff, Marty G.; Cabeza, Roberto

2017-01-01

Multivariate functional connectivity analyses of neuroimaging data have revealed the importance of complex, distributed interactions between disparate yet interdependent brain regions. Recent work has shown that topological properties of functional brain networks are associated with individual and group differences in cognitive performance, including in episodic memory. After constructing functional whole-brain networks derived from an event-related fMRI study of memory retrieval, we examined differences in functional brain network architecture between forgotten and remembered words. This study yielded three main findings. First, graph theory analyses showed that successfully remembering compared to forgetting was associated with significant changes in the connectivity profile of the left hippocampus and a corresponding increase in efficient communication with the rest of the brain. Second, bivariate functional connectivity analyses indicated stronger interactions between the left hippocampus and a retrieval assembly for remembered versus forgotten items. This assembly included the left precuneus, left caudate, bilateral supramarginal gyrus, and the bilateral dorsolateral superior frontal gyrus. Integrative properties of the retrieval assembly were greater for remembered than forgotten items. Third, whole-brain modularity analyses revealed that successful memory retrieval was marginally significantly associated with a less segregated modular architecture in the network. The magnitude of the decreases in modularity between remembered and forgotten conditions was related to memory performance. These findings indicate that increases in integrative properties at the nodal, retrieval assembly, and whole-brain topological levels facilitate memory retrieval, while also underscoring the potential of multivariate brain connectivity approaches for providing valuable new insights into the neural bases of memory processes. PMID:28112460

A three-dimensional stratigraphic model for aggrading submarine channels based on laboratory experiments, numerical modeling, and sediment cores

NASA Astrophysics Data System (ADS)

Limaye, A. B.; Komatsu, Y.; Suzuki, K.; Paola, C.

2017-12-01

Turbidity currents deliver clastic sediment from continental margins to the deep ocean, and are the main driver of landscape and stratigraphic evolution in many low-relief, submarine environments. The sedimentary architecture of turbidites—including the spatial organization of coarse and fine sediments—is closely related to the aggradation, scour, and lateral shifting of channels. Seismic stratigraphy indicates that submarine, meandering channels often aggrade rapidly relative to lateral shifting, and develop channel sand bodies with high vertical connectivity. In comparison, the stratigraphic architecture developed by submarine, braided is relatively uncertain. We present a new stratigraphic model for submarine braided channels that integrates predictions from laboratory experiments and flow modeling with constraints from sediment cores. In the laboratory experiments, a saline density current developed subaqueous channels in plastic sediment. The channels aggraded to form a deposit with a vertical scale of approximately five channel depths. We collected topography data during aggradation to (1) establish relative stratigraphic age, and (2) estimate the sorting patterns of a hypothetical grain size distribution. We applied a numerical flow model to each topographic surface and used modeled flow depth as a proxy for relative grain size. We then conditioned the resulting stratigraphic model to observed grain size distributions using sediment core data from the Nankai Trough, offshore Japan. Using this stratigraphic model, we establish new, quantitative predictions for the two- and three-dimensional connectivity of coarse sediment as a function of fine-sediment fraction. Using this case study as an example, we will highlight outstanding challenges in relating the evolution of low-relief landscapes to the stratigraphic record.

Hydrocarbons in New Guinea, controlled by basement fabric, Mesozoic extension and Tertiary convergent margin tectonics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hill, K.C.; Kendrick, R.D.; Crowhurst, P.V.

1996-01-01

Most models for the tectonic evolution of New Guinea involve Early and Late Miocene arc-continent collisions, creating an orogenic belt. Structural trends and prospectivity are then analyzed in terms of belts across the country; the Fold Belt (with the discovered oil and gas fields), the Mobile Belt and the accreted arcs. This model inhibits realistic assessment of prospectivity. It now appears the Mobile Belt formed by Oligocene compression then by Early Miocene extension, related to slab-rollback, that unroofed metamorphic core complexes adjacent to starved half-grabens. The grabens filled in the Middle Miocene and were largely transported intact during the Pliocenemore » arc-collision. Early Miocene reefs and hypothesized starved basin source rocks create a viable play throughout northern New Guinea as in the Salawati Basin. The Pliocene clastic section is locally prospective due to overthrusting and deep burial. Within the Fold Belt, the site and types of oil and gas fields are largely controlled by the basement architecture. This controlled the transfer zones and depocentres during Mesozoic extension and the location of major basement uplifts during compression. In PNG, the Bosavi lineament separates an oil province from a gas province. In Irian Jaya the transition from a relatively competent sequence to a rifted sequence west of [approx]139[degrees]E may also be a gas-oil province boundary. Understanding, in detail, the compartmentalization of inverted blocks and areas of thin-skinned thrusting, controlled by the basement architecture, will help constrain hydrocarbon prospectivity.« less

Hydrocarbons in New Guinea, controlled by basement fabric, Mesozoic extension and Tertiary convergent margin tectonics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hill, K.C.; Kendrick, R.D.; Crowhurst, P.V.

1996-12-31

Most models for the tectonic evolution of New Guinea involve Early and Late Miocene arc-continent collisions, creating an orogenic belt. Structural trends and prospectivity are then analyzed in terms of belts across the country; the Fold Belt (with the discovered oil and gas fields), the Mobile Belt and the accreted arcs. This model inhibits realistic assessment of prospectivity. It now appears the Mobile Belt formed by Oligocene compression then by Early Miocene extension, related to slab-rollback, that unroofed metamorphic core complexes adjacent to starved half-grabens. The grabens filled in the Middle Miocene and were largely transported intact during the Pliocenemore » arc-collision. Early Miocene reefs and hypothesized starved basin source rocks create a viable play throughout northern New Guinea as in the Salawati Basin. The Pliocene clastic section is locally prospective due to overthrusting and deep burial. Within the Fold Belt, the site and types of oil and gas fields are largely controlled by the basement architecture. This controlled the transfer zones and depocentres during Mesozoic extension and the location of major basement uplifts during compression. In PNG, the Bosavi lineament separates an oil province from a gas province. In Irian Jaya the transition from a relatively competent sequence to a rifted sequence west of {approx}139{degrees}E may also be a gas-oil province boundary. Understanding, in detail, the compartmentalization of inverted blocks and areas of thin-skinned thrusting, controlled by the basement architecture, will help constrain hydrocarbon prospectivity.« less

Sedimentary processes and architecture of Upper Cretaceous deep-sea channel deposits: a case from the Skole Nappe, Polish Outer Carpathians

NASA Astrophysics Data System (ADS)

Łapcik, Piotr

2018-02-01

Deep-sea channels are one of the architectonic elements, forming the main conduits for sand and gravel material in the turbidite depositional systems. Deep-sea channel facies are mostly represented by stacking of thick-bedded massive sandstones with abundant coarse-grained material, ripped-up clasts, amalgamation and large scale erosional structures. The Manasterz Quarry of the Ropianka Formation (Upper Cretaceous, Skole Nappe, Carpathians) contains a succession of at least 31 m of thick-bedded high-density turbidites alternated with clast-rich sandy debrites, which are interpreted as axial deposits of a deep-sea channel. The section studied includes 5 or 6 storeys with debrite basal lag deposits covered by amalgamated turbidite fills. The thickness of particular storeys varies from 2.5 to 13 m. Vertical stacking of similar facies through the whole thickness of the section suggest a hierarchically higher channel-fill or a channel complex set, with an aggradation rate higher than its lateral migration. Such channel axis facies cannot aggrade without simultaneous aggradation of levee confinement, which was distinguished in an associated section located to the NW from the Manasterz Quarry. Lateral offset of channel axis facies into channel margin or channel levee facies is estimated at less than 800 m. The Manasterz Quarry section represents mostly the filling and amalgamation stage of channel formation. The described channel architectural elements of the Ropianka Formation are located within the so-called Łańcut Channel Zone, which was previously thought to be Oligocene but may have been present already in the Late Cretaceous.

Synergistic and additive properties of the beta-globin locus control region (LCR) revealed by 5'HS3 deletion mutations: implication for LCR chromatin architecture.

PubMed

Fang, Xiangdong; Sun, Jin; Xiang, Ping; Yu, Man; Navas, Patrick A; Peterson, Kenneth R; Stamatoyannopoulos, George; Li, Qiliang

2005-08-01

Deletion of the 234-bp core element of the DNase I hypersensitive site 3 (5'HS3) of the locus control region (LCR) in the context of a human beta-globin locus yeast artificial chromosome (beta-YAC) results in profound effects on globin gene expression in transgenic mice. In contrast, deletion of a 2.3-kb 5'HS3 region, which includes the 234-bp core sequence, has a much milder phenotype. Here we report the effects of these deletions on chromatin structure in the beta-globin locus of adult erythroblasts. The 234-bp 5'HS3 deletion abolished histone acetylation throughout the beta-globin locus; recruitment of RNA polymerase II (pol II) to the LCR and beta-globin gene promoter was reduced to a basal level; and formation of all the 5' DNase I hypersensitive sites of the LCR was disrupted. The 2.3-kb 5'HS3 deletion mildly reduced the level of histone acetylation but did not change the profile across the whole locus; the 5' DNase I hypersensitive sites of the LCR were formed, but to a lesser extent; and recruitment of pol II was reduced, but only marginally. These data support the hypothesis that the LCR forms a specific chromatin structure and acts as a single entity. Based on these results we elaborate on a model of LCR chromatin architecture which accommodates the distinct phenotypes of the 5'HS3 and HS3 core deletions.

Comparative effectiveness research as choice architecture: the behavioral law and economics solution to the health care cost crisis.

PubMed

Korobkin, Russell

2014-02-01

With the Patient Protection and Affordable Care Act ("ACA") set to dramatically increase access to medical care, the problem of rising costs will move center stage in health law and policy discussions. "Consumer directed health care" proposals, which provide patients with financial incentives to equate marginal costs and benefits of care at the point of treatment, demand more decisionmaking ability from consumers than is plausible due to bounded rationality. Proposals that seek to change the incentives of health care providers threaten to create conflicts of interest between doctors and patients. New approaches are desperately needed. This Article proposes a government-facilitated but market-based approach to improving efficiency in the private market for medical care that I call "relative value health insurance." This approach focuses on the "choice architecture" necessary to enable even boundedly rational patients to contract for an efficient level of health care services through their health insurance purchase decisions. It uses comparative effectiveness research, which the ACA funds at a significant level for the first time, to rate medical treatments on a scale of one to ten based on their relative value, taking into account expected costs and benefits. These relative value ratings would enable consumers to contract with insurers for different levels of medical care at different prices, reflecting different cost-quality trade-offs. The Article describes both the benefits of relative value health insurance and the impediments to its implementation. It concludes with a brief discussion of how relative value ratings could also help to rationalize expenditures on public health insurance programs.

Distinguishing Long-Term Controls on Fluvial Architecture in the Lance Formation, Bighorn Basin, Wyoming

NASA Astrophysics Data System (ADS)

McHarge, J. L.; Hajek, E. A.; Heller, P. L.

2007-12-01

Allogenic processes are considered a prime control on the stratigraphic distribution of channel bodies, however, recent studies have indicated that autogenic stratigraphic organization may occur within fluvial systems on basin- filling time scales (105-106 years). Groupings or clusters of closely-spaced channel bodies can be produced by several different mechanisms, including both allogenic and autogenic processes. Commonly, sand- dominated intervals in stratigraphic successions are interpreted as incised-valley fills produced by base-level changes. In contrast, long-timescale organization of river avulsion can generate similar stratigraphic patterns. For example, sand-dominated intervals in the fluvial Lance Formation (Maastrichtian; Bighorn Basin, WY) have been interpreted as incised-valley fills formed during sea-level lowstand. However, closely-spaced sand bodies in the Ferris Formation (Lance equivalent; Hanna Basin, WY) are interpreted as aggradational in origin, and have been compared to autogenic avulsion stratigraphy produced in experimental basins. We evaluate the Lance Formation in the southern Bighorn Basin in an effort to determine whether these sand-dominated intervals are truly incised- valley fills resulting from sea-level changes, or if they were generated by autogenic processes. The Lance Formation crops out in the western and southern margins of the basin, exposing relatively proximal and distal portions of the system. By comparing alluvial architecture between exposures, we evaluate similarities and differences from upstream to downstream and look for evidence of intrinsic and extrinsic controls on deposition. In both localities, the Lance Formation comprises multi-story sheet sandstones and smaller, single-story sandstones. Observed changes from upstream to downstream in the system include: 1) increasing paleoflow depths (from ~30-60 cm to ~70-120 cm); 2) decreasing preservation of fine-grained material within channel bodies; 3) increasing proportion of amalgamated, multi-story sand bodies; and 4) increasing lateral continuity of multi-story sand bodies. These results indicate that upstream, channel-body spacing is dominantly controlled by aggradational processes and may be the result of autogenic avulsion clustering, whereas downstream, evidence of incision and amalgamation indicate that base-level may have limited and controlled sand-body architecture.

Reliability of skin biopsies in determining accurate tumor margins: a retrospective study after Mohs micrographic surgery.

PubMed

Koslosky, Cynthia Lynn; El Tal, Abdel Kader; Workman, Benjamin; Tamim, Hani; Durance, Michelle Christine; Mehregan, David Ali

2014-09-01

Skin biopsy reports of basal cell carcinoma and squamous cell carcinoma are often accompanied by comments on the margins. A physician's management can be influenced by such reports, particularly when the margins are reported as clear and no further interventions are pursued. To retrospectively review pathology margins on Mohs micrographic surgery (MMS) cases performed at a University Center and to compare biopsy margins with the Mohs margins found on the first stage. Data collection of 1,000 cases of Mohs surgery was obtained regarding margins on skin biopsy and compared with margins on the first stage of MMS. Overall, of the biopsies that showed only deep margin involvement, a lateral margin was seen on 32% of the first stages of MMS. Conversely, of the biopsies that showed only lateral margin involvement, a deep margin was seen on 14% of the first stages of MMS. Of the biopsies that showed clear margins, a margin was seen in 30% of the cases on the first stage of MMS. Skin biopsies processed through the "bread-loafing" technique are not reliable in detecting accurate margins, and therefore, a biopsy report should not include margin involvement within it.

Constraining the sedimentology and stratigraphy of submarine intraslope lobe deposits using exhumed examples from the Karoo Basin, South Africa

NASA Astrophysics Data System (ADS)

Spychala, Y. T.; Hodgson, D. M.; Flint, S. S.; Mountney, N. P.

2015-06-01

Intraslope lobe deposits provide a process record of the infill of accommodation on submarine slopes and their recognition enables the accurate reconstruction of the stratigraphic evolution of submarine slope systems. Extensive exposures of discrete sand-prone packages in Units D/E and E, Fort Brown Formation, Karoo Basin, South Africa, permit analysis of the sedimentology and stacking patterns of three intraslope lobe complexes and their palaeogeographic reconstruction via bed-scale analysis and physical correlation of key stratal surfaces. The sand-prone packages comprise tabular, aggradationally to slightly compensationally stacked lobe deposits with constituent facies associations that can be attributed to lobe axis, lobe off-axis, lobe-fringe and distal lobe-fringe environments. Locally, intraslope lobe deposits are incised by low aspect ratio channels that mark basinward progradation of the deepwater system. The origin of accommodation on the slope for lobe deposition is interpreted to be due to differential compaction or healing of scars from mass wasting processes. The stacking patterns and sedimentary facies arrangement identified in this study are distinct from those of more commonly recognized basin-floor lobe deposits, thereby enabling the establishment of recognition criteria for intraslope lobe deposits in other less well exposed and studied fine-grained systems. Compared to basin floor lobes, intraslope lobes are smaller in volume, influenced by higher degrees of confinement, and tend to show aggradational stacking patterns.

How you slice it: smarter segmentation for your sales force.

PubMed

Waaser, Ernest; Dahneke, Marshall; Pekkarinen, Michael; Weissel, Michael

2004-03-01

Three years ago, 70-year-old Hill-Rom Incorporated was in a position familiar to many mature businesses: The company was strong but needed to be stronger. It was a top producer of hospital beds and specialty mattresses, its core product lines. It also had competitive complementary lines of stretchers, furniture, and architectural equipment. It had an extensive customer base, a respected sales force, and solid profit margins. But by the time Ernest Waaser took over as chief executive in early 2001, revenue growth had been slowing, and competition was on the rise. To secure Hill-Rom's place in the market, Waaser decided to focus first on the sales organization--partly because the cost of sales had risen gradually over the past five years and partly because acquisitions and other initiatives had made the sales organization more complex. The CEO took several steps to restructure the sales force. First, the company changed its customer segments to better reflect customers' demands and financial status, ultimately targeting two main groups: key and prime customers. It then changed the overall structure of the sales organization so it could tailor its approach to these two segments; key customers received more specialized service than prime customers. Finally, Hill-Rom adjusted the sales force after the company took an in-depth look at historical data on products and services and sales completed. Reasons for staffing changes were carefully communicated to the sales force. Because of Hill-Rom's initiatives, the cost of sales is down, short-term revenue growth is up, the outlook for long-term revenue growth looks bright, sales and profit margins are up, and customer satisfaction has increased. Best practice, indeed.

Phylogeographic heterogeneity of the brown macroalga Sargassum horneri (Fucaceae) in the northwestern Pacific in relation to late Pleistocene glaciation and tectonic configurations.

PubMed

Hu, Zi-Min; Uwai, Shinya; Yu, Shen-Hui; Komatsu, Teruhisa; Ajisaka, Tetsuro; Duan, De-Lin

2011-09-01

Pleistocene glacial oscillations and associated tectonic processes are believed to have influenced the historical abundances and distribution of organisms in the Asia Northwest Pacific (ANP). Accumulating evidence indicates that factors shaping tempospatial population dynamics and distribution patterns of marine taxa vary with biogeographical latitude, pelagic behaviour and oceanographic regimes. To detect what kinds of historical and contemporary factors affected genetic connectivity, phylogeographic profiles of littoral macroalga Sargassum horneri in the ANP were analysed based on mitochondrial (Cox3) and chloroplast (rbcL) data sets. Five distinct clades were recovered. A strong signature of biogeographical structure was revealed (Φ(CT) = 0.487, P < 0.0001) derived from remarkable differentiation in clade distribution, as clade I is restricted to Chinese marginal seas (Yellow-Bohai Sea, East China Sea and South China Sea), whereas clades II-V are discontinuously scattered around the main Islands of Japan. Furthermore, two secondary contact regions were identified along the south Japan-Pacific coastline. This significant differentiation between the two basins may reflect historical glacial isolation in the northwestern Pacific, which is congruent with the estimates of clade divergence and demographic expansion during the late Quaternary low sea levels. Analysis of molecular variance and the population-pair statistic F(ST) also revealed significant genetic structural differences between Chinese marginal seas and the Japanese basin. This exceptional phylogeographic architecture in S. horneri, initially shaped by historical geographic isolation during the late Pleistocene ice age and physical biogeographical barriers, can be complicated by oceanographic regimes (ocean surface currents) and relocating behaviour such as oceanic drifting. © 2011 Blackwell Publishing Ltd.

Volcaniclastic dykes tell on fracturing, explosive eruption and lateral collapse at Stromboli volcano (Italy)

NASA Astrophysics Data System (ADS)

Vezzoli, Luigina; Corazzato, Claudia

2016-05-01

In the upper part of the Stromboli volcano, in the Le Croci and Bastimento areas, two dyke-like bodies of volcanic breccia up to two-metre thick crosscut and intrude the products of Vancori and Neostromboli volcanoes. We describe the lithofacies association of these unusual volcaniclastic dykes, interpret the setting of dyke-forming fractures and the emplacement mechanism of internal deposits, and discuss their probable relationships with the explosive eruption and major lateral collapse events that occurred at the end of the Neostromboli period. The dyke volcaniclastic deposits contain juvenile magmatic fragments (pyroclasts) suggesting a primary volcanic origin. Their petrographic characteristics are coincident with the Neostromboli products. The architecture of the infilling deposits comprises symmetrically-nested volcaniclastic units, separated by sub-vertical boundaries, which are parallel to the dyke margins. The volcanic units are composed of distinctive lithofacies. The more external facies is composed of fine and coarse ash showing sub-vertical laminations, parallel to the contact wall. The central facies comprises stratified, lithic-rich breccia and lapilli-tuff, whose stratification is sub-horizontal and convolute, discordant to the dyke margins. Only at Le Croci dyke, the final unit shows a massive tuff-breccia facies. The volcaniclastic dykes experienced a polyphasic geological evolution comprising three stages. The first phase consisted in fracturing, explosive intrusion related to magma rising and upward injection of magmatic fluids and pyroclasts. The second phase recorded the dilation of fractures and their role as pyroclastic conduits in an explosive eruption possibly coeval with the lateral collapse of the Neostromboli lava cone. Finally, in the third phase, the immediately post-eruption mass-flow remobilization of pyroclastic deposits took place on the volcano slopes.

Beyond the Seafloor: a Plio-Pleistocene Archive of Glacial Geomorphology from Basin-Wide 3D Seismic Reflection Data on the Mid-Norwegian Shelf

NASA Astrophysics Data System (ADS)

Newton, A.; Huuse, M.

2015-12-01

Oil and gas exploration on the mid-Norwegian shelf has created an extensive geophysical and geological database. As such, this margin has become one of the most comprehensively studied formerly-glaciated continental margins in the world. Industrial operations have concentrated on the structure and geohazard potential of glacial sediments whilst academic work has looked at reconstructing environmental conditions during and since the Last Glacial Maximum (LGM). This has generally consisted of mapping seafloor glacial geomorphology and a limited number of shallow sediment cores. Despite the increasingly large volume of 3D seismic reflection data available across the majority of the shelf, only limited work has been carried out investigating the oldest glaciations. A Plio-Pleistocene archive of glacial-interglacial history is preserved offshore and represents a unique study site because of the availability of 100s of 3D seismic reflection datasets. This database allows numerous different glacial erosion events and glacial landforms to be imaged throughout the glacially-derived NAUST Formation. We present an inventory of glacial history for the mid-Norwegian shelf and review the implications for the glacial history of Northwest Europe. This record shows glacial landforms such as iceberg scours, mega-scale glacial lineations and grounding-zone wedges, each of which provides an insight into ice characteristics. Dating is limited to a few tentative dates based on side-wall core data but we infer a further dating chronology based on dated sediments from the Voring Plateau, fluctuations in the benthic δ18O derived global sea level record, interpretation of seismic facies and the overall architecture. Glacial evidence is present regularly throughout the stratigraphy with the earliest evidence for marine terminating ice found at the base of the NAUST Formation at ~2.8 Ma.

Potential application of a handheld confocal endomicroscope imaging system using a variety of fluorophores in experimental gliomas and normal brain.

PubMed

Martirosyan, Nikolay L; Georges, Joseph; Eschbacher, Jennifer M; Cavalcanti, Daniel D; Elhadi, Ali M; Abdelwahab, Mohammed G; Scheck, Adrienne C; Nakaji, Peter; Spetzler, Robert F; Preul, Mark C

2014-02-01

The authors sought to assess the feasibility of a handheld visible-wavelength confocal endomicroscope imaging system (Optiscan 5.1, Optiscan Pty., Ltd.) using a variety of rapid-acting fluorophores to provide histological information on gliomas, tumor margins, and normal brain in animal models. Mice (n = 25) implanted with GL261 cells were used to image fluorescein sodium (FNa), 5-aminolevulinic acid (5-ALA), acridine orange (AO), acriflavine (AF), and cresyl violet (CV). A U251 glioma xenograft model in rats (n = 5) was used to image sulforhodamine 101 (SR101). A swine (n = 3) model with AO was used to identify confocal features of normal brain. Images of normal brain, obvious tumor, and peritumoral zones were collected using the handheld confocal endomicroscope. Histological samples were acquired through biopsies from matched imaging areas. Samples were visualized with a benchtop confocal microscope. Histopathological features in corresponding confocal images and photomicrographs of H & E-stained tissues were reviewed. Fluorescence induced by FNa, 5-ALA, AO, AF, CV, and SR101 and detected with the confocal endomicroscope allowed interpretation of histological features. Confocal endomicroscopy revealed satellite tumor cells within peritumoral tissue, a definitive tumor border, and striking fluorescent cellular and subcellular structures. Fluorescence in various tumor regions correlated with standard histology and known tissue architecture. Characteristic features of different areas of normal brain were identified as well. Confocal endomicroscopy provided rapid histological information precisely related to the site of microscopic imaging with imaging characteristics of cells related to the unique labeling features of the fluorophores. Although experimental with further clinical trial validation required, these data suggest that intraoperative confocal imaging can help to distinguish normal brain from tumor and tumor margin and may have application in improving intraoperative decisions during resection of brain tumors.

Design Considerations for a Launch Vehicle Development Flight Instrumentation System

NASA Technical Reports Server (NTRS)

Johnson, Martin L.; Crawford, Kevin

2011-01-01

When embarking into the design of a new launch vehicle, engineering models of expected vehicle performance are always generated. While many models are well established and understood, some models contain design features that are only marginally known. Unfortunately, these analytical models produce uncertainties in design margins. The best way to answer these analytical issues is with vehicle level testing. The National Aeronautics and Space Administration respond to these uncertainties by using a vehicle level system called the Development Flight Instrumentation, or DFI. This DFI system can be simple to implement, with only a few measurements, or it may be a sophisticated system with hundreds of measurement and video, without a recording capability. From experience with DFI systems, DFI never goes away. The system is renamed and allowed to continue, in most cases. Proper system design can aid the transition to future data requirements. This paper will discuss design features that need to be considered when developing a DFI system for a launch vehicle. It will briefly review the data acquisition units, sensors, multiplexers and recorders, telemetry components and harnessing. It will present a reasonable set of requirements which should be implemented in the beginning of the program in order to start the design. It will discuss a simplistic DFI architecture that could be the basis for the next NASA launch vehicle. This will be followed by a discussion of the "experiences gained" from a past DFI system implementation, such as the very successful Ares I-X test flight. Application of these design considerations may not work for every situation, but they may direct a path toward success or at least make one pause and ask the right questions.

Exploring contrasts between fast and slow rifting

NASA Astrophysics Data System (ADS)

de Montserrat Navarro, A.; Morgan, J. P.; Hall, R.; White, L. T.

2016-12-01

Researchers are now finding that extension sometimes occurs at rates much faster than the mean rates observed in the development of passive margins. Examples of rapid and ultra-rapid extension are found in several locations in Eastern Indonesia, including northern and central Sulawesi as well as eastern- and westernmost New Guinea. Periods of extension are associated with sedimentary basin growth and phases of crustal melting and rapid uplift. This is recorded by seismic imagery of basins offshore Sulawesi and New Guinea as well as through new field studies of the onshore geology in these regions. A growing body of new geochronological and biostratigraphic data provides some control on the rates of processes, indicating that extension rates can be up to an order of magnitude faster than the rates inferred for the more commonly studied rift settings (e.g. Atlantic opening, East African Rift, Australia-Antarctica opening). We explore a suite of numerical experiments comparing the evolution of these `fast' (20-100 mm/year full rate) rifting models to rifting at slow and ultra-slow extension rates (5-20 mm/year). The experiments focus on the 2-D margin architecture and predicted melt volumes. These extension episodes occurring in Eastern Indonesia take place under different thermal conditions. Thus, we also investigate the role of the initial thermal structure in controlling the evolution of rifting. We explore to what depths hot lower crust and mantle can be exhumed by fast rifting, and infer that many of the extensional basins in SE Asia cannot be explained by simple rifting episodes of fragments of continental crust. Instead, fast extension appears to be initiated by subduction related processes that we will briefly discuss.

Cryptic crustal events during the Taconic Orogeny elucidated through LA-ICPMS studies of volcanic zircons, southern Appalachians, Alabama

NASA Astrophysics Data System (ADS)

Herrmann, A. D.; Leslie, S.; Haynes, J.

2017-12-01

Despite a long history of stratigraphic work, many questions remain about the tectonic setting of the Taconic orogeny during the early late Ordovician. Several different global paleogeographic hypotheses exist about the driving force that led to this orogeny. While some studies suggest that the closing of the Iapetus ocean was caused by the collision of the North American and South American plates, most studies suggest that island arc systems collided with the passive continental margin of North America. Nevertheless, disagreement exists on how to explain the stratigraphic architecture of the siliciclastic sequences representing the erosion of the Taconic Highlands in an island arc setting. Some studies suggest the collision was analogous to the modern Banda Arc system with the development of a foreland basin and a sedimentary wedge, while other studies call for the presence of a back arc basin. Here we present U-Pb results of volcanic zircons that are associated with the magmatic activity during this time. Previous studies focused on slender zircons for age dating. However, in this study we analyzed several large zircons from close to the volcanic center in Alabama that have inherited cores in order to test for the presence of geochemical evidence for multiple crustal events. While the rims have ages consistent with the Taconic Orogeny ( 450 my), the cores have much older ages ( 1000 my). Our results support the hypothesis that during the closing of the Iapetus ocean, Precambrian and Cambrian sediments from the passive continental margin were subducted and incorporated into the volcanic system. This led to the inclusion of Precambrian zircons into melts associated with the Taconic Orogeny. Overall, our study supports the presence of subduction of preexisting sedimentary rocks and potentially the presence of a sedimentary wedge.

The Prognostic Value of Varying Definitions of Positive Resection Margin in Patients with Colorectal Cancer Liver Metastases.

PubMed

Wang, Jane; Margonis, Georgios Antonios; Amini, Neda; Andreatos, Nikolaos; Yuan, Chunhui; Damaskos, Christos; Antoniou, Efstathios; Garmpis, Nikolaos; Buettner, Stefan; Barbon, Carlotta; Deshwar, Amar; He, Jin; Burkhart, Richard; Pawlik, Timothy M; Wolfgang, Christopher L; Weiss, Matthew J

2018-04-09

Varying definitions of resection margin clearance are currently employed among patients with colorectal cancer liver metastases (CRLM). Specifically, a microscopically positive margin (R1) has alternatively been equated with an involved margin (margin width = 0 mm) or a margin width < 1 mm. Consequently, patients with a margin width of 0-1 mm (sub-mm) are inconsistently classified in either the R0 or R1 categories, thus obscuring the prognostic implications of sub-mm margins. Six hundred thirty-three patients who underwent resection of CRLM were identified. Both R1 definitions were alternatively employed and multivariable analysis was used to determine the predictive power of each definition, as well as the prognostic implications of a sub-mm margin. Five hundred thirty-nine (85.2%) patients had a margin width ≥ 1 mm, 42 had a sub-mm margin width, and 52 had an involved margin (0 mm). A margin width ≥ 1 mm was associated with improved survival vs. a sub-mm margin (65 vs. 36 months; P = 0.03) or an involved margin (65 vs. 33 months; P < 0.001). No significant difference in survival was detected between patients with involved vs. sub-mm margins (P = 0.31). A sub-mm margin and an involved margin were both independent predictors of worse OS (HR 1.66, 1.04-2.67; P = 0.04, and HR 2.14, 1.46-3.16; P < 0.001, respectively) in multivariable analysis. Importantly, after combining the two definitions, patients with either an involved margin or a sub-mm margin were associated with worse OS in multivariable analysis (HR 1.94, 1.41-2.65; P < 0.001). Patients with involved or sub-mm margins demonstrated a similar inferior OS vs. patients with a margin width > 1 mm. Consequently, a uniform definition of R1 as a margin width < 1 mm should perhaps be employed by future studies.

Newly identified helper bacteria stimulate ectomycorrhizal formation in Populus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Labbe, Jessy L.; Weston, David J.; Dunkirk, Nora

Mycorrhiza helper bacteria (MHB) are known to increase host root colonization by mycorrhizal fungi but the molecular mechanisms and potential tripartite trophic interactions are poorly understood. Through an effort to study Populus microbiome, we isolated 21 Pseudomonas strains from native Populus deltoides roots. These bacterial isolates were characterized and screened for MHB effectiveness on the Populus-Laccaria system. Two other Pseudomonas strains (i.e., Pf-5 and BBc6R8) from existing collections were also included as reference in the screening process. We analyzed Laccaria bicolor S238N growth rate, mycelial architecture and transcriptional changes induced by the contrasting Pseudomonas strains (i.e., inhibitory, neutral and beneficial).more » We characterized 17 out of the 21 Pseudomonas strains from the Populus rhizosphere with positive effects on L. bicolor S238N growth, as well as on Populus root architecture and colonization by L. bicolor S238N across three Populus species. Four of seven reporter genes, Tra1, Tectonin2, Gcn5 and Cipc1, thought to be specific to the interaction with strain BBc6R8, were induced or repressed while interacting with six (i.e., GM17, GM33, GM41, GM48, Pf-5 and BBc6R8) of the tested Pseudomonas strains. GM41 promoted the highest roots colonization across three Populus species but most notably in P. deltoides, which is otherwise, poorly colonized by L. bicolor. Here we report novel MHB strains isolated from native Populus that improve roots colonization. This tripartite relationship could be exploited in nursery production for target Populus species/genotypes as a means of improving establishment and survival in marginal lands.« less

Newly identified helper bacteria stimulate ectomycorrhizal formation in Populus

DOE PAGES

Labbe, Jessy L.; Weston, David J.; Dunkirk, Nora; ...

2014-10-24

Mycorrhiza helper bacteria (MHB) are known to increase host root colonization by mycorrhizal fungi but the molecular mechanisms and potential tripartite trophic interactions are poorly understood. Through an effort to study Populus microbiome, we isolated 21 Pseudomonas strains from native Populus deltoides roots. These bacterial isolates were characterized and screened for MHB effectiveness on the Populus-Laccaria system. Two other Pseudomonas strains (i.e., Pf-5 and BBc6R8) from existing collections were also included as reference in the screening process. We analyzed Laccaria bicolor S238N growth rate, mycelial architecture and transcriptional changes induced by the contrasting Pseudomonas strains (i.e., inhibitory, neutral and beneficial).more » We characterized 17 out of the 21 Pseudomonas strains from the Populus rhizosphere with positive effects on L. bicolor S238N growth, as well as on Populus root architecture and colonization by L. bicolor S238N across three Populus species. Four of seven reporter genes, Tra1, Tectonin2, Gcn5 and Cipc1, thought to be specific to the interaction with strain BBc6R8, were induced or repressed while interacting with six (i.e., GM17, GM33, GM41, GM48, Pf-5 and BBc6R8) of the tested Pseudomonas strains. GM41 promoted the highest roots colonization across three Populus species but most notably in P. deltoides, which is otherwise, poorly colonized by L. bicolor. Here we report novel MHB strains isolated from native Populus that improve roots colonization. This tripartite relationship could be exploited in nursery production for target Populus species/genotypes as a means of improving establishment and survival in marginal lands.« less

Affordability Approaches for Human Space Exploration

NASA Technical Reports Server (NTRS)

Holladay, Jon; Smith, David Alan

2012-01-01

The design and development of historical NASA Programs (Apollo, Shuttle and International Space Station), have been based on pre-agreed missions which included specific pre-defined destinations (e.g., the Moon and low Earth orbit). Due to more constrained budget profiles, and the desire to have a more flexible architecture for Mission capture as it is affordable, NASA is working toward a set of Programs that are capability based, rather than mission and/or destination specific. This means designing for a performance capability that can be applied to a specific human exploration mission/destination later (sometime years later). This approach does support developing systems to flatter budgets over time, however, it also poses the challenge of how to accomplish this effectively while maintaining a trained workforce, extensive manufacturing, test and launch facilities, and ensuring mission success ranging from Low Earth Orbit to asteroid destinations. NASA Marshall Space Flight Center (MSFC) in support of Exploration Systems Directorate (ESD) in Washington, DC has been developing approaches to track affordability across multiple Programs. The first step is to ensure a common definition of affordability: the discipline to bear cost in meeting a budget with margin over the life of the program. The second step is to infuse responsibility and accountability for affordability into all levels of the implementing organization since affordability is no single person s job; it is everyone s job. The third step is to use existing data to identify common affordability elements organized by configuration (vehicle/facility), cost, schedule, and risk. The fourth step is to analyze and trend this affordability data using an affordability dashboard to provide status, measures, and trends for ESD and Program level of affordability tracking. This paper will provide examples of how regular application of this approach supports affordable and therefore sustainable human space exploration architecture.

An integrated workflow to assess the remaining potential of mature hydrocarbon basins: a case study from Northwest Germany (Upper Jurassic/Lower Cretaceous, Lower Saxony Basin)

NASA Astrophysics Data System (ADS)

Seyfang, Björn; Aigner, Thomas; Munsterman, Dirk K.; Irmen, Anton

2017-04-01

Mature hydrocarbon provinces require a high level of geological understanding in order to extend the lives of producing fields, to replace reserves through smaller targets and to reduce the risks of exploring for more and more subtle hydrocarbon traps. Despite a large number of existing wells in the area studied in this paper, the depositional environments and the stratigraphic architecture were still poorly known. In order to improve the geological understanding, we propose a workflow to assess the remaining reservoir potential of mature hydrocarbon areas, integrating cores, cuttings, well-logs, biostratigraphy and seismic data. This workflow was developed for and is exemplified with the northwest of the Lower Saxony Basin (LSB), a mature hydrocarbon province in northwest Germany, but can be applied in a similar fashion to other areas. Systematic integration of lithofacies analysis, chrono- and sequence stratigraphy, combined with electrofacies analysis and modern digital methods like neural network-based lithology determination and 3D facies modelling provides a high-resolution understanding of the spatial facies and reservoir architecture in the study area. Despite widely correlatable litho-units in the Upper Jurassic and Lower Cretaceous in the LSB, complex heterogeneous sedimentary systems can be found in the basin's marginal parts. Two new play types were determined in the study area, showing a remaining potential for stratigraphic hydrocarbon traps. The results of this exploration scale study also provide the basis for re-evaluations on a field development scale. On a basin scale, this study may encourage further data acquisition and re-evaluations to discover previously unknown reservoirs.

From hippocampus to whole-brain: The role of integrative processing in episodic memory retrieval.

PubMed

Geib, Benjamin R; Stanley, Matthew L; Dennis, Nancy A; Woldorff, Marty G; Cabeza, Roberto

2017-04-01

Multivariate functional connectivity analyses of neuroimaging data have revealed the importance of complex, distributed interactions between disparate yet interdependent brain regions. Recent work has shown that topological properties of functional brain networks are associated with individual and group differences in cognitive performance, including in episodic memory. After constructing functional whole-brain networks derived from an event-related fMRI study of memory retrieval, we examined differences in functional brain network architecture between forgotten and remembered words. This study yielded three main findings. First, graph theory analyses showed that successfully remembering compared to forgetting was associated with significant changes in the connectivity profile of the left hippocampus and a corresponding increase in efficient communication with the rest of the brain. Second, bivariate functional connectivity analyses indicated stronger interactions between the left hippocampus and a retrieval assembly for remembered versus forgotten items. This assembly included the left precuneus, left caudate, bilateral supramarginal gyrus, and the bilateral dorsolateral superior frontal gyrus. Integrative properties of the retrieval assembly were greater for remembered than forgotten items. Third, whole-brain modularity analyses revealed that successful memory retrieval was marginally significantly associated with a less segregated modular architecture in the network. The magnitude of the decreases in modularity between remembered and forgotten conditions was related to memory performance. These findings indicate that increases in integrative properties at the nodal, retrieval assembly, and whole-brain topological levels facilitate memory retrieval, while also underscoring the potential of multivariate brain connectivity approaches for providing valuable new insights into the neural bases of memory processes. Hum Brain Mapp 38:2242-2259, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Control of rift asymmetry and segmentation on the thermal architecture of hyperextended rift systems: insights from Pyrenean field observations and numerical modelling

NASA Astrophysics Data System (ADS)

Lescoutre, Rodolphe; Tugend, Julie; Brune, Sascha; Manatschal, Gianreto

2017-04-01

Mid-Cretaceous rift basins are exposed in the Pyrenees providing key information on rifted domain formation that is not available at present-day rift system. Substantial paleotemperature and thermochronological data have been collected and published in numerous recent papers. These data show a strong heterogeneity in the distribution of peak temperatures within the Cretaceous rift basins. Locations that experienced relatively high or low temperatures appear to cluster in specific areas along strike. These areas have been interpreted as either reflecting hot and cold conditions during rifting, or alternatively, a change in the polarity of a strongly asymmetric rift systems. In this study, we test if the observed variability of peak temperatures can be explained by segmentation and a change in polarity of an asymmetrical upper/lower plate rift model. To this aim we restore the observed syn- to early post-rift peak temperatures to their paleo-location within sections across the evolving rift system. In the meantime, we conduct numerical models of rift migration leading to asymmetrical extension that are benchmarked with geological and geophysical observations from the Pyrenees. From the models, we extract thermal information at different stages of rifting that are finally compared to the thermal data from the Pyrenean Cretaceous rift basins. This work employs a novel approach by comparing thermal output from numerical modelling with the distribution of peak temperatures and thermal gradient from field data. As such, these results may have substantial implications to further understand the pre-orogenic thermal evolution of the Pyrenean rift system and the role of segmentation. More generally, the results of this work may unravel the role of rift asymmetry and segmentation on the thermal architecture of hyperextended rift basins and margins.

Mass-transport deposits and the advantages of a real three-dimensional perspective (Invited)

NASA Astrophysics Data System (ADS)

Moscardelli, L. G.; Wood, L. J.

2010-12-01

Mass-transport deposits (MTDs) form a significant component of the stratigraphic record in ancient and modern deepwater basins worldwide. However, the difficulties encountered when performing direct observations of these submarine units, the limited area covered by geophysical surveys acquired by research institutions, and the often surficial nature of seafloor data collected by federal agencies represent major hurdles in understanding submarine mass-movement dynamics. Three-dimensional seismic reflectivity imaging, drawn mainly from energy exploration in deepwater regions of the world, has allowed researchers to describe the architecture of MTDs at unprecedented spatial and temporal scales. In this talk, we present observations made using thousands of square kilometers of three-dimensional seismic data acquired by the oil and gas industry in offshore Trinidad, Morocco, and the Gulf of Mexico, where MTDs are a common occurrence in the stratigraphic record. Detailed mapping of MTD architecture has allowed us to better understand the role that MTDs have in continental-margin evolution. Morphometric data obtained from the mapping of MTDs is used to model tsunamigenic waves and their potential affect of coastal areas. The effect of low permeability MTDs on reservoir and aquifer fluid behavior has important implications, enhancing the economic importance of understanding the occurrence and distribution of these deposits. The recognition of MTD processes and morphology leads to new understanding of the processes possibly active in shaping other planets. Such analogs speak to a possible deepwater origin for features on Mars previously attributed to subaerial events. As industry-quality 3D seismic data become increasingly available to academic institutions, current studies become important bell weathers for future analysis of MTDs and processes in oceans of this planet and beyond.

Facies associations, depositional environments and stratigraphic framework of the Early Miocene-Pleistocene successions of the Mukah-Balingian Area, Sarawak, Malaysia

NASA Astrophysics Data System (ADS)

Murtaza, Muhammad; Rahman, Abdul Hadi Abdul; Sum, Chow Weng; Konjing, Zainey

2018-02-01

Thirty-five stratigraphic section exposed along the Mukah-Selangau road in the Mukah-Balingian area have been studied. Sedimentological and palynological data have been integrated to gain a better insight into the depositional architecture of the area. Broadly, the Mukah-Balingian area is dominated by fluvial, floodplain and estuarine related coal-bearing deposits. The Balingian, Begrih and Liang formations have been described and interpreted in terms of seven facies association. These are: FA1 - Fluvial-dominated channel facies association; FA2 - Tide-influenced channel facies association; FA3 - Tide-dominated channel facies association; FA4 - Floodplain facies association; FA5 - Estuarine central basin-mud flats facies association; FA6 - Tidal flat facies association and FA7 - Coastal swamps and marshes facies association. The Balingian Formation is characterised by the transgressive phase in the base, followed by a regressive phase in the upper part. On the basis of the occurrence of Florscheutzia trilobata with Florscheutzia levipoli, the Early to Middle Miocene age has been assigned to the Balingian Formation. The distinct facies pattern and foraminifera species found from the samples taken from the Begrih outcrop imply deposition in the intertidal flats having pronounced fluvio-tidal interactions along the paleo-margin. Foraminiferal data combined with the pronounced occurrence of Stenochlaena laurifolia suggest at least the Late Miocene age for the Begrih Formation. The internal stratigraphic architecture of the Liang Formation is a function of a combination of sea level, stable tectonic and autogenic control. Based on stratigraphic position, the Middle Pliocene to Pleistocene age for the Liang Formation is probable. The Balingian, Begrih and Liang formations display deposits of multiple regressive-transgressive cycles while the sediments were derived from the uplifted Penian high and Rajang group.

Tectono-stratigraphic evolution and crustal architecture of the Orphan Basin during North Atlantic rifting

NASA Astrophysics Data System (ADS)

Gouiza, Mohamed; Hall, Jeremy; Welford, J. Kim

2017-04-01

The Orphan Basin is located in the deep offshore of the Newfoundland margin, and it is bounded by the continental shelf to the west, the Grand Banks to the south, and the continental blocks of Orphan Knoll and Flemish Cap to the east. The Orphan Basin formed in Mesozoic time during the opening of the North Atlantic Ocean between eastern Canada and western Iberia-Europe. This work, based on well data and regional seismic reflection profiles across the basin, indicates that the continental crust was affected by several extensional episodes between the Jurassic and the Early Cretaceous, separated by events of uplift and erosion. The preserved tectono-stratigraphic sequences in the basin reveal that deformation initiated in the eastern part of the Orphan Basin in the Jurassic and spread towards the west in the Early Cretaceous, resulting in numerous rift structures filled with a Jurassic-Lower Cretaceous syn-rift succession and overlain by thick Upper Cretaceous to Cenozoic post-rift sediments. The seismic data show an extremely thinned crust (4-16 km thick) underneath the eastern and western parts of the Orphan Basin, forming two sub-basins separated by a wide structural high with a relatively thick crust (17 km thick). Quantifying the crustal architecture in the basin highlights the large discrepancy between brittle extension localized in the upper crust and the overall crustal thinning. This suggests that continental deformation in the Orphan Basin involved, in addition to the documented Jurassic and Early Cretaceous rifting, an earlier brittle rift phase which is unidentifiable in seismic data and a depth-dependent thinning of the crust driven by localized lower crust ductile flow.

Morphodynamics and stratigraphic architecture of shelf-edge deltas subject to constant vs. dynamic environmental forcings

NASA Astrophysics Data System (ADS)

Straub, K. M.

2017-12-01

When deltas dock at the edge of continental margins they generally construct thick stratigraphic intervals and activate channelized continental slope systems. Deposits of shelf-edge deltas have the capacity to store detailed paleo-environmental records, given their location in the source to sink system. However, present day highstand sea-level conditions have pushed most deltaic systems well inbound of their shelf-edges, making it difficult to study their space-time dynamics and resulting stratigraphic products. Several competing theories describe how deltas and their downslope environments respond to sea-level cycles of varying magnitude and periodicity. We explore these hypotheses in a physical experiment where the topographic evolution of a coupled delta and downdip slope system was monitored at high temporal and spatial resolution. The experiment had three stages. In the first stage a delta aggraded at the shelf-edge under constant water and sediment supply, in addition to a constant generation of accommodation through a sea-level rise. In the second stage the sediment transport system responded to low magnitude and high frequency sea-level cycles. Finally, in the third stage the transport system responded to a high magnitude and long period sea-level cycle. In each stage, fine sediment from the input grain size distribution and dissolved salt in the input water supply promoted plunging hyperpycnal flows. Specifically, we compare the mean and temporal variability of the sediment delivered to the slope system between stages. In addition, we compare stratigraphic architecture and sediment sizes delivered to the slope system in each stage. These results are used to improve inversion of slope deposits for paleo-environmental forcings.

Geophysical Investigation of Avon Valley, West-Central Montana, using Gravity and Seismic Reflection Profiling

NASA Astrophysics Data System (ADS)

Knatterud, L.; Mosolf, J.; Speece, M. A.; Zhou, X.

2014-12-01

The Avon Valley and adjacent mountains in west-central Montana lie within the Lewis and Clark Line, a major system of WNW-striking faults and folds that transect the more northerly structural grain of the northern Rockies and represent alternating episodes of transtensional and transpressional deformation. The northwest-trending valley has been previously interpreted as an extensional half graben filled with Tertiary sedimentary and volcanic deposits; however, little-to-no geophysical constraints on basin architecture or the thickness of Tertiary fill have been reported. A major northwest-striking fault with significant normal displacement clearly bounds the valley to the northeast, juxtaposing Tertiary sedimentary deposits against Proterozoic-Mesozoic units deformed by shortening structures and crosscut by Cretaceous granitic intrusions. Tertiary volcanic deposits unconformably overlying faulted and folded Phanerozoic-Proterozoic sequences in the eastern Garnet Range bound the valley to the southwest, but in the past no faults had been mapped along this margin. New mapping by the Montana Bureau of Mines and Geology (MBMG) has identified a system of high-angle, northwest- and northeast-striking, oblique-slip faults along the southwest border of the Avon calling into question if the valley is a half, full, or asymmetrical graben. Geophysical data has recently been acquired by Montana Tech to help define the structural architecture of the Avon Valley and the thickness of its Tertiary fill. Gravity data and a short seismic reflection profile have been collected and a preliminary interpretation of these data indicates a half graben with a series of normal faults bounding the western side of the valley. Ongoing gravity data collection throughout 2014 should refine this interpretation by better defining the bedrock-Tertiary interface at depth.

Entry, Descent, and Landing technological barriers and crewed MARS vehicle performance analysis

NASA Astrophysics Data System (ADS)

Subrahmanyam, Prabhakar; Rasky, Daniel

2017-05-01

Mars has been explored historically only by robotic crafts, but a crewed mission encompasses several new engineering challenges - high ballistic coefficient entry, hypersonic decelerators, guided entry for reaching intended destinations within acceptable margins for error in the landing ellipse, and payload mass are all critical factors for evaluation. A comprehensive EDL parametric analysis has been conducted in support of a high mass landing architecture by evaluating three types of vehicles -70° Sphere Cone, Ellipsled and SpaceX hybrid architecture called Red Dragon as potential candidate options for crewed entry vehicles. Aerocapture at the Martian orbit of about 400 km and subsequent Entry-from-orbit scenarios were investigated at velocities of 6.75 km/s and 4 km/s respectively. A study on aerocapture corridor over a range of entry velocities (6-9 km/s) suggests that a hypersonic L/D of 0.3 is sufficient for a Martian aerocapture. Parametric studies conducted by varying aeroshell diameters from 10 m to 15 m for several entry masses up to 150 mt are summarized and results reveal that vehicles with entry masses in the range of about 40-80 mt are capable of delivering cargo with a mass on the order of 5-20 mt. For vehicles with an entry mass of 20 mt to 80 mt, probabilistic Monte Carlo analysis of 5000 cases for each vehicle were run to determine the final landing ellipse and to quantify the statistical uncertainties associated with the trajectory and attitude conditions during atmospheric entry. Strategies and current technological challenges for a human rated Entry, Descent, and Landing to the Martian surface are presented in this study.

Dynamics of Braided Channels, Bars, and Associated Deposits Under Experimental Density Currents

NASA Astrophysics Data System (ADS)

Limaye, A. B. S.; Jean-Louis, G.; Paola, C.

2015-12-01

Turbidity currents are the principal agents that transfer clastic sediment from continental margins to the deep ocean. The extensive sedimentary deposits that result can record influences from fluvial transport, ocean currents, and seafloor bathymetry; decoding these controls is key to understanding long-term continental denudation and the formation of hydrocarbon reservoirs. Experimental turbidity currents often use pre-formed, single-thread channels, but more recent experiments and seafloor observations suggest that braided channels also develop in submarine environments. Yet controls on the formation of submarine braided channels and relationships between these channels and stratigraphic evolution remain largely untested. We have conducted a series of experiments to determine the conditions conducive to forming braided submarine channels, and to relate channel geometry and kinematics to deposit architecture. Dissolved salt supplies the excess density of the experimental turbidity currents, which transport plastic, sand-sized sediment as bedload across a test section two meters long and one meter wide. Our experiments indicate that braided channels can form as constructional features without prior erosion for a range of input water and sediment fluxes. Channel migration, avulsion, and aggradation construct sedimentary deposits with bars at a variety of scales. Bar geometry and channel kinematics are qualitatively similar under subaerial and subaqueous experiments with other parameters fixed. We will present quantitative analyses of the relationships between channel geometry and mobility and deposit architecture, at scales from individual bars to the entire deposit, and compare these results to control experiments with subaerial braiding. These experimental results suggest parallels between subaerial and subaqueous braiding, and help to constrain forward models for stratigraphic evolution and inverse methods for estimating flow conditions from turbidites.

Crustal architecture of the Faroe-Shetland Margin: insights from a newly merged high resolution gravity and magnetic dataset

NASA Astrophysics Data System (ADS)

Rippington, Stephen; Mazur, Stan; Anderson, Chris

2014-05-01

The Faroe-Shetland region is geologically complex; it has undergone several phases of extension and rifting since the middle Palaeozoic (Ritchie et al., 2011; Coward et al., 2003), culminating in the Eocene with continental breakup between Northwest Europe and Greenland (Gernigon et al., 2012). Final breakup may have been facilitated by the presence of the Iceland Plume and was accompanied by the emplacement of voluminous basaltic rocks, attributed to the North Atlantic Igneous Province (White and McKenzie, 1989). It is difficult to image beneath the thick Paleogene basalts in the region using conventional seismic methods, because the high impedance contrast between the sediments and shallow basalts causes strong reflections. These mask deeper and weaker reflections and cause prominent inter-bed multiples (White et al., 1999). Consequently, determining the location and shape of basins and basement highs, and elucidating the timing and manner of their formation, remains a major cause of uncertainty in the appraisal of the hydrocarbon potential of the region. Gravity and magnetic data record variations in the density and susceptibility of the entire crust. Consequently, the thick basalt piles that are shallow in the section do not hinder the ability to detect deeper features. Instead, the principal challenge is distinguishing superposed bodies, with different densities and susceptibilities, from the combined gravity and magnetic anomalies. In this study, seismic data and horizons from the shallow section are used in combination with gravity and magnetic data to produce map view interpretations, and 2D and 3D models of the crust in the Faroe-Shetland region. These models help distinguish important variations in timing of rifting in different basins, and reveal the crustal architecture of the Faroe-Shetland Basin from the seabed to the Moho. We present a new structural and kinematic interpretation of the geology of the region, and propose an asymmetric simple shear model for the Faroe-Shetland segment of the UK Atlantic Margin. The authors would like to acknowledge the management at ARKeX and PGS for giving permission to present this work. Coward, M.., Dewey, J.F., Hempton, M., and Holroyd, J., 2003, Tectonic evolution, in Evans, D., Graham, C.G., Armour, A., and P, B. eds., Millenium Atlas: petroleum geology of the central and northern North Sea, Geological Society of London. Gernigon, L., Gaina, C., Olesen, O., Ball, P.J., Péron-Pinvidic, G., and Yamasaki, T., 2012, The Norway Basin revisited: From continental breakup to spreading ridge extinction: Marine and Petroleum Geology, v. 35, no. 1, p. 1-19. Ritchie, J.D., Ziska, H., Johnson, H., and Evans, D., 2011, Structure, in Ritchie, J.D., Ziska, H., Johnson, H., and Evans, D. eds., Geology of the Faroe-Shetland Basin and adjacent areas, British Geological Survey, Faroeses Earth and Energy Directorate, p. 9-70. White, R.S., Fruehn, J., Richardson, K.R., Cullen, E., Kirk, W., and Latkiewicz, C., 1999, Faeroes Large Aperture Research Experiment ( FLARE ): imaging through basalt, in Fleet, A.J. and Boldy, S.A.R. eds., Petroleum Geology of Northwest Europe and Global Perspectives: Proceedings of the 5th Conference, Geological Society of London, p. 1243-1252. White, R., and McKenzie, D., 1989, Magmatism at Rift Zones: The Generation of Volcanic Continental Margins: Journal of Geophysical Research, v. 94, no. B6, p. 7685-7729.

The structures, stratigraphy and evolution of the Gulf of Corinth rift, Greece

NASA Astrophysics Data System (ADS)

Taylor, Brian; Weiss, Jonathan R.; Goodliffe, Andrew M.; Sachpazi, Maria; Laigle, Mireille; Hirn, Alfred

2011-06-01

A multichannel seismic and bathymetry survey of the central and eastern Gulf of Corinth (GoC), Greece, reveals the offshore fault geometry, seismic stratigraphy and basin evolution of one of Earths most active continental rift systems. Active, right-stepping, en-echelon, north-dipping border faults trend ESE along the southern Gulf margin, significantly overlapping along strike. The basement offsets of three (Akrata-Derveni, Sithas and Xylocastro) are linked. The faults are biplanar to listric: typically intermediate angle (˜35° in the centre and 45-48° in the east) near the surface but decreasing in dip and/or intersecting a low- or shallow-angle (15-20° in the centre and 19-30° in the east) curvi-planar reflector in the basement. Major S-dipping border faults were active along the northern margin of the central Gulf early in the rift history, and remain active in the western Gulf and in the subsidiary Gulf of Lechaio, but unlike the southern border faults, are without major footwall uplift. Much of the eastern rift has a classic half-graben architecture whereas the central rift has a more symmetric w- or u-shape. The narrower and shallower western Gulf that transects the >40-km-thick crust of the Hellenides is associated with a wider distribution of overlapping high-angle normal faults that were formerly active on the Peloponnesus Peninsula. The easternmost sector includes the subsidiary Gulfs of Lechaio and Alkyonides, with major faults and basement structures trending NE, E-W and NW. The basement faults that control the rift architecture formed early in the rift history, with little evidence (other than the Vrachonisida fault along the northern margin) in the marine data for plan view evolution by subsequent fault linkage. Several have maximum offsets near one end. Crestal collapse graben formed where the hanging wall has pulled off the steeper onto the shallower downdip segment of the Derveni Fault. The dominant strikes of the Corinth rift faults gradually rotate from 090-120° in the basement and early rift to 090-100° in the latest rift, reflecting a ˜10° rotation of the opening direction to the 005° presently measured by GPS. The sediments include a (locally >1.5-km-) thick, early-rift section, and a late-rift section (also locally >1.5-km-thick) that we subdivide into three sequences and correlate with seven 100-ka glacio-eustatic cycles. The Gulf depocentre has deepened through time (currently >700 mbsl) as subsidence has outpaced sedimentation. We measure the minimum total horizontal extension across the central and eastern Gulf as varying along strike between 4 and 10 km, and estimate full values of 6-11 km. The rift evolution is strongly influenced by the inherited basement fabric. The regional NNW structural fabric of the Hellenic nappes changes orientation to ESE in the Parnassos terrane, facilitating the focused north-south extension observed offshore there. The basement-penetrating faults lose seismic reflectivity above the 4-14-km-deep seismogenic zone. Multiple generations and dips of normal faults, some cross-cutting, accommodate extension beneath the GoC, including low-angle (15-20°) interfaces in the basement nappes. The thermally cool forearc setting and cross-orogen structures unaccompanied by magmatism make this rift a poor analogue and unlikely precursor for metamorphic core complex formation.

Relations between tectonics and sedimentation along the Eastern Sardinian margin (Western Tyrrhenian Sea) : from rifting to reactivation

NASA Astrophysics Data System (ADS)

Gaullier, Virginie; Chanier, Frank; Vendeville, Bruno; Lymer, Gaël; Maillard, Agnès; Thinon, Isabelle; Lofi, Johanna; Sage, Françoise; Giresse, Pierre; Bassetti, Maria-Angela

2014-05-01

The offshore-onshore project "METYSS-METYSAR" aims at better understand the Miocene-Pliocene relationships between crustal tectonics, salt tectonics, and sedimentation along the Eastern Sardinian margin, Western Tyrrhenian Sea. In this key-area, the Tyrrhenian back-arc basin underwent recent rifting (9-5 Ma), pro parte coeval with the Messinian Salinity Crisis (MSC, 5.96-5.33 Ma), sea-floor spreading starting during Pliocene times. Thereby, the Tyrrhenian basin and the Eastern Sardinian margin are excellent candidates for studying the mechanisms of extreme lithospheric stretching and thinning, the role of pre-existing structural fabric during and after rifting, and the reactivation of a passive margin and the associated deformation and sedimentation patterns during the MSC. We looked at the respective contributions of crustal and salt tectonics in quantifying vertical and horizontal movements, using especially the seismic markers of the MSC. Overall, we delineate the history of rifting and tectonic reactivation in the area. The distribution maps respectively of the Messinian Erosion Surface and of Messinian units (Upper Unit and Mobile Unit) show that a rifted basin already existed by Messinian time. This reveals a major pre-MSC rifting across the entire domain. Because salt tectonics can create fan-shaped geometries in sediments, syn-rift deposits have to be carefully re-examined in order to decipher the effects of crustal tectonics (rifting) and thin-skinned salt tectonics. Our data surprisingly show that there are no clues for Messinian syn-rift sediments along the East-Sardinia Basin and Cornaglia Terrace, hence no evidence for rifting after Late Tortonian times. Nevertheless, widespread deformation occurred during the Pliocene and can only be attributed to post-rift reactivation. This reactivation is characterized not only by normal faulting but also by contractional structures. Some Pliocene vertical movements caused localized gravity gliding of the mobile salt and its Late Messinian and Early Pliocene brittle overburden. "METYSAR" fieldwork onshore was conducted in the Orosei region and showed that the main present-day Cedrino river follows the trend of a paleo-valley that cuts through the underlying granitic basement and alterites. These deposits, along with the basement, were likely eroded during Messinian times, then reworked during a marine transgression. Micro-fauna in these fine-grained marine sediments are of Upper Pliocene age. The strata dip by 20° to 30° and trend NNE-SSW, a direction which is sub-parallel to the main tectonic structures involved in the rifting of the margin. The tilted Pliocene strata were overlain by volcanic flows, some dating from Upper Pliocene time. Field mapping has evidenced that there was a paleo-topographic relief, trending NNE-SSW, that controlled the sediment deposition. These results indicate that the post-Messinian tectonic activity, which is also visible offshore, controlled the sedimentary architecture and the paleogeography of this area. Onshore, there are signs of neither Lower-Pliocene marine deposits nor Gilbert deltas. The absence of such sedimentary edifices, which are characteristic of the Pliocene refilling of the Mediterranean basin are clues about significant post-rift vertical movements in the Tyrrhenian sea.

Post-resection mucosal margin shrinkage in oral cancer: quantification and significance.

PubMed

Mistry, Rajesh C; Qureshi, Sajid S; Kumaran, C

2005-08-01

The importance of tumor free margins in outcome of cancer surgery is well known. Often the pathological margins are reported to be significantly smaller than the in situ margins. This discrepancy is due to margin shrinkage the quantum of which has not been studied in patients with oral cancers. To quantify the shrinkage of mucosal margin following excision for carcinoma of the oral tongue and buccal mucosa. Mucosal margins were measured prior to resection and half an hour after excision in 27 patients with carcinoma of the tongue and buccal mucosa. The mean margin shrinkage was assessed and the variables affecting the quantum of shrinkage analyzed. The mean shrinkage from the in situ to the post resection margin status was 22.7% (P < 0.0001). The mean shrinkage of the tongue margins was 23.5%, compared to 21.2% for buccal mucosa margins. The mean shrinkage in T1/T2 tumors (25.6%) was significantly more than in T3/T4 (9.2%, P < 0.011). There is significant shrinkage of mucosal margins after surgery. Hence this should be considered and appropriate margins should be taken at initial resection to prevent the agony of post-operative positive surgical margins. Copyright 2005 Wiley-Liss, Inc.

Prevalence and predictive factors for the detection of carcinoma in cavity margin performed at the time of breast lumpectomy.

PubMed

Tengher-Barna, Iulia; Hequet, Delphine; Reboul-Marty, Jeanne; Frassati-Biaggi, Annonciade; Seince, Nathalie; Rodrigues-Faure, Anabela; Uzan, Michèle; Ziol, Marianne

2009-02-01

Margin resection status is a major risk factor for the development of local recurrence in breast conservation therapy for carcinoma. Tumor bed excision sent as separate orientated cavity margins represents a tool to verify the completeness of the carcinoma resection. We aimed to (1) determine the prevalence of positive cavity margin and its influence on subsequent surgical treatment and (2) identify potential predictive factors for positive cavity margins. From 2003 to 2006, 107 (57 years; 30-88) consecutive patients who underwent a lumpectomy for carcinoma with four orientated cavity margins for carcinoma were selected. Preoperative clinical, radiological and histological data, perioperative macroscopic characteristics and definitive histological analysis results were recorded. Lumpectomy or cavity margins were considered as positive when the distance from carcinoma to the margin was less than or equal to 3 mm. Histological examination of cavity margins showed carcinoma in 38 patients (35%), therefore modifying subsequent surgical therapy in 33 cases. Examination of the cavity margins led (1) to avoiding surgical re-excision in 20 cases (lumpectomy margins were positive and the cavity margins negative), (2) to performing a mastectomy or a re-excision in 13 cases (carcinoma was detected in the cavity margins although the lumpectomy margins were negative or tumor size was superior to 3 cm). Between preoperative and perioperative parameters, US scan and macroscopic size of the tumor were predictive factors for positive cavity margins whereas characteristics of the carcinoma determined on biopsy samples and macroscopic status of the lumpectomy margins were not. Our study confirms that the systematic practice of cavity margin resection avoids surgical re-excision and reduces the likelihood of underestimating the extent of the tumor.

The marginal band system in nymphalid butterfly wings.

PubMed

Taira, Wataru; Kinjo, Seira; Otaki, Joji M

2015-01-01

Butterfly wing color patterns are highly complex and diverse, but they are believed to be derived from the nymphalid groundplan, which is composed of several color pattern systems. Among these pattern systems, the marginal band system, including marginal and submarginal bands, has rarely been studied. Here, we examined the color pattern diversity of the marginal band system among nymphalid butterflies. Marginal and submarginal bands are usually expressed as a pair of linear bands aligned with the wing margin. However, a submarginal band can be expressed as a broken band, an elongated oval, or a single dot. The marginal focus, usually a white dot at the middle of a wing compartment along the wing edge, corresponds to the pupal edge spot, one of the pupal cuticle spots that signify the locations of color pattern organizing centers. A marginal band can be expressed as a semicircle, an elongated oval, or a pair of eyespot-like structures, which suggest the organizing activity of the marginal focus. Physical damage at the pupal edge spot leads to distal dislocation of the submarginal band in Junonia almana and in Vanessa indica, suggesting that the marginal focus functions as an organizing center for the marginal band system. Taken together, we conclude that the marginal band system is developmentally equivalent to other symmetry systems. Additionally, the marginal band is likely a core element and the submarginal band a paracore element of the marginal band system, and both bands are primarily specified by the marginal focus organizing center.

Draper Station Analysis Tool

NASA Technical Reports Server (NTRS)

Bedrossian, Nazareth; Jang, Jiann-Woei; McCants, Edward; Omohundro, Zachary; Ring, Tom; Templeton, Jeremy; Zoss, Jeremy; Wallace, Jonathan; Ziegler, Philip

2011-01-01

Draper Station Analysis Tool (DSAT) is a computer program, built on commercially available software, for simulating and analyzing complex dynamic systems. Heretofore used in designing and verifying guidance, navigation, and control systems of the International Space Station, DSAT has a modular architecture that lends itself to modification for application to spacecraft or terrestrial systems. DSAT consists of user-interface, data-structures, simulation-generation, analysis, plotting, documentation, and help components. DSAT automates the construction of simulations and the process of analysis. DSAT provides a graphical user interface (GUI), plus a Web-enabled interface, similar to the GUI, that enables a remotely located user to gain access to the full capabilities of DSAT via the Internet and Webbrowser software. Data structures are used to define the GUI, the Web-enabled interface, simulations, and analyses. Three data structures define the type of analysis to be performed: closed-loop simulation, frequency response, and/or stability margins. DSAT can be executed on almost any workstation, desktop, or laptop computer. DSAT provides better than an order of magnitude improvement in cost, schedule, and risk assessment for simulation based design and verification of complex dynamic systems.

Terrestrial Micro Renewable Energy Applications of Space Technology

NASA Astrophysics Data System (ADS)

Komerath, N. M.; Komerath, P. P.

This paper explores the synergy between technologies intended for extraterrestrial in situ resource utilization and those for terrestrial mass-market micro renewable power generation systems. The case for a micro renewable energy architecture is presented. The obstacles hindering market success are summarized, along with opportunities from recent demonstrations suggesting that the public appetite for sophisticated technology worldwide may be underappreciated by technical researchers. Technical innovations from space research are summarized along with estimates of possible conversion efficiencies. It is argued that the cost-effectiveness of micro power generation must be viewed through the value of the first few watts of available power, rather than the marginal cost per kilowatt-hour of electric power from utility power grids. This leads to the finding that the actual target cost per unit power, and efficiency, are well within reach of space technology products. Hybrid systems integrating power extraction from multiple resources, and adaptable for multiple applications, can break through mass market price barriers. Recent work to develop learning resources and test beds as part of a Micro Renewable Energy Laboratory is summarized.

Source-gated transistors for order-of-magnitude performance improvements in thin-film digital circuits

NASA Astrophysics Data System (ADS)

Sporea, R. A.; Trainor, M. J.; Young, N. D.; Shannon, J. M.; Silva, S. R. P.

2014-03-01

Ultra-large-scale integrated (ULSI) circuits have benefited from successive refinements in device architecture for enormous improvements in speed, power efficiency and areal density. In large-area electronics (LAE), however, the basic building-block, the thin-film field-effect transistor (TFT) has largely remained static. Now, a device concept with fundamentally different operation, the source-gated transistor (SGT) opens the possibility of unprecedented functionality in future low-cost LAE. With its simple structure and operational characteristics of low saturation voltage, stability under electrical stress and large intrinsic gain, the SGT is ideally suited for LAE analog applications. Here, we show using measurements on polysilicon devices that these characteristics lead to substantial improvements in gain, noise margin, power-delay product and overall circuit robustness in digital SGT-based designs. These findings have far-reaching consequences, as LAE will form the technological basis for a variety of future developments in the biomedical, civil engineering, remote sensing, artificial skin areas, as well as wearable and ubiquitous computing, or lightweight applications for space exploration.

Molecular and Functional Characterization of Lymphoid Progenitor Subsets Reveals a Bipartite Architecture of Human Lymphopoiesis.

PubMed

Alhaj Hussen, Kutaiba; Vu Manh, Thien-Phong; Guimiot, Fabien; Nelson, Elisabeth; Chabaane, Emna; Delord, Marc; Barbier, Maxime; Berthault, Claire; Dulphy, Nicolas; Alberdi, Antonio José; Burlen-Defranoux, Odile; Socié, Gerard; Bories, Jean Christophe; Larghero, Jerôme; Vanneaux, Valérie; Verhoeyen, Els; Wirth, Thierry; Dalod, Marc; Gluckman, Jean Claude; Cumano, Ana; Canque, Bruno

2017-10-17

The classical model of hematopoiesis established in the mouse postulates that lymphoid cells originate from a founder population of common lymphoid progenitors. Here, using a modeling approach in humanized mice, we showed that human lymphoid development stemmed from distinct populations of CD127 - and CD127 + early lymphoid progenitors (ELPs). Combining molecular analyses with in vitro and in vivo functional assays, we demonstrated that CD127 - and CD127 + ELPs emerged independently from lympho-mono-dendritic progenitors, responded differently to Notch1 signals, underwent divergent modes of lineage restriction, and displayed both common and specific differentiation potentials. Whereas CD127 - ELPs comprised precursors of T cells, marginal zone B cells, and natural killer (NK) and innate lymphoid cells (ILCs), CD127 + ELPs supported production of all NK cell, ILC, and B cell populations but lacked T potential. On the basis of these results, we propose a "two-family" model of human lymphoid development that differs from the prevailing model of hematopoiesis. Copyright © 2017 Elsevier Inc. All rights reserved.

Overview of the MEDLI Project

NASA Technical Reports Server (NTRS)

Gazarik, Michael J.; Hwang, Helen; Little, Alan; Cheatwood, Neil; Wright, Michael; Herath, Jeff

2007-01-01

The Mars Science Laboratory Entry, Descent, and Landing Instrumentation (MEDLI) Project's objectives are to measure aerothermal environments, sub-surface heatshield material response, vehicle orientation, and atmospheric density for the atmospheric entry and descent phases of the Mars Science Laboratory (MSL) entry vehicle. The flight science objectives of MEDLI directly address the largest uncertainties in the ability to design and validate a robust Mars entry system, including aerothermal, aerodynamic and atmosphere models, and thermal protection system (TPS) design. The instrumentation suite will be installed in the heatshield of the MSL entry vehicle. The acquired data will support future Mars entry and aerocapture missions by providing measured atmospheric data to validate Mars atmosphere models and clarify the design margins for future Mars missions. MEDLI thermocouple and recession sensor data will significantly improve the understanding of aeroheating and TPS performance uncertainties for future missions. MEDLI pressure data will permit more accurate trajectory reconstruction, as well as separation of aerodynamic and atmospheric uncertainties in the hypersonic and supersonic regimes. This paper provides an overview of the project including the instrumentation design, system architecture, and expected measurement response.

Overview of the MEDLI Project

NASA Technical Reports Server (NTRS)

Gazarik, Michael J.; Little, Alan; Cheatwood, F. Neil; Wright, Michael J.; Herath, Jeff A.; Martinez, Edward R.; Munk, Michelle; Novak, Frank J.; Wright, Henry S.

2008-01-01

The Mars Science Laboratory Entry, Descent, and Landing Instrumentation (MEDLI) Project s objectives are to measure aerothermal environments, sub-surface heatshield material response, vehicle orientation, and atmospheric density for the atmospheric entry and descent phases of the Mars Science Laboratory (MSL) entry vehicle. The flight science objectives of MEDLI directly address the largest uncertainties in the ability to design and validate a robust Mars entry system, including aerothermal, aerodynamic and atmosphere models, and thermal protection system (TPS) design. The instrumentation suite will be installed in the heatshield of the MSL entry vehicle. The acquired data will support future Mars entry and aerocapture missions by providing measured atmospheric data to validate Mars atmosphere models and clarify the design margins for future Mars missions. MEDLI thermocouple and recession sensor data will significantly improve the understanding of aeroheating and TPS performance uncertainties for future missions. MEDLI pressure data will permit more accurate trajectory reconstruction, as well as separation of aerodynamic and atmospheric uncertainties in the hypersonic and supersonic regimes. This paper provides an overview of the project including the instrumentation design, system architecture, and expected measurement response.

Space Launch System Complex Decision-Making Process

NASA Technical Reports Server (NTRS)

Lyles, Garry; Flores, Tim; Hundley, Jason; Monk, Timothy; Feldman,Stuart

2012-01-01

The Space Shuttle program has ended and elements of the Constellation Program have either been cancelled or transitioned to new NASA exploration endeavors. The National Aeronautics and Space Administration (NASA) has worked diligently to select an optimum configuration for the Space Launch System (SLS), a heavy lift vehicle that will provide the foundation for future beyond low earth orbit (LEO) large-scale missions for the next several decades. From Fall 2010 until Spring 2011, an SLS decision-making framework was formulated, tested, fully documented, and applied to multiple SLS vehicle concepts at NASA from previous exploration architecture studies. This was a multistep process that involved performing figure of merit (FOM)-based assessments, creating Pass/Fail gates based on draft threshold requirements, performing a margin-based assessment with supporting statistical analyses, and performing sensitivity analysis on each. This paper focuses on the various steps and methods of this process (rather than specific data) that allowed for competing concepts to be compared across a variety of launch vehicle metrics in support of the successful completion of the SLS Mission Concept Review (MCR) milestone.

Propulsion Controls Modeling for a Small Turbofan Engine

NASA Technical Reports Server (NTRS)

Connolly, Joseph W.; Csank, Jeffrey T.; Chicatelli, Amy; Franco, Kevin

2017-01-01

A nonlinear dynamic model and propulsion controller are developed for a small-scale turbofan engine. The small-scale turbofan engine is based on the Price Induction company's DGEN 380, one of the few turbofan engines targeted for the personal light jet category. Comparisons of the nonlinear dynamic turbofan engine model to actual DGEN 380 engine test data and a Price Induction simulation are provided. During engine transients, the nonlinear model typically agrees within 10 percent error, even though the nonlinear model was developed from limited available engine data. A gain scheduled proportional integral low speed shaft controller with limiter safety logic is created to replicate the baseline DGEN 380 controller. The new controller provides desired gain and phase margins and is verified to meet Federal Aviation Administration transient propulsion system requirements. In understanding benefits, there is a need to move beyond simulation for the demonstration of advanced control architectures and technologies by using real-time systems and hardware. The small-scale DGEN 380 provides a cost effective means to accomplish advanced controls testing on a relevant turbofan engine platform.

Control-Relevant Modeling, Analysis, and Design for Scramjet-Powered Hypersonic Vehicles

NASA Technical Reports Server (NTRS)

Rodriguez, Armando A.; Dickeson, Jeffrey J.; Sridharan, Srikanth; Benavides, Jose; Soloway, Don; Kelkar, Atul; Vogel, Jerald M.

2009-01-01

Within this paper, control-relevant vehicle design concepts are examined using a widely used 3 DOF (plus flexibility) nonlinear model for the longitudinal dynamics of a generic carrot-shaped scramjet powered hypersonic vehicle. Trade studies associated with vehicle/engine parameters are examined. The impact of parameters on control-relevant static properties (e.g. level-flight trimmable region, trim controls, AOA, thrust margin) and dynamic properties (e.g. instability and right half plane zero associated with flight path angle) are examined. Specific parameters considered include: inlet height, diffuser area ratio, lower forebody compression ramp inclination angle, engine location, center of gravity, and mass. Vehicle optimizations is also examined. Both static and dynamic considerations are addressed. The gap-metric optimized vehicle is obtained to illustrate how this control-centric concept can be used to "reduce" scheduling requirements for the final control system. A classic inner-outer loop control architecture and methodology is used to shed light on how specific vehicle/engine design parameter selections impact control system design. In short, the work represents an important first step toward revealing fundamental tradeoffs and systematically treating control-relevant vehicle design.

BCM: toolkit for Bayesian analysis of Computational Models using samplers.

PubMed

Thijssen, Bram; Dijkstra, Tjeerd M H; Heskes, Tom; Wessels, Lodewyk F A

2016-10-21

Computational models in biology are characterized by a large degree of uncertainty. This uncertainty can be analyzed with Bayesian statistics, however, the sampling algorithms that are frequently used for calculating Bayesian statistical estimates are computationally demanding, and each algorithm has unique advantages and disadvantages. It is typically unclear, before starting an analysis, which algorithm will perform well on a given computational model. We present BCM, a toolkit for the Bayesian analysis of Computational Models using samplers. It provides efficient, multithreaded implementations of eleven algorithms for sampling from posterior probability distributions and for calculating marginal likelihoods. BCM includes tools to simplify the process of model specification and scripts for visualizing the results. The flexible architecture allows it to be used on diverse types of biological computational models. In an example inference task using a model of the cell cycle based on ordinary differential equations, BCM is significantly more efficient than existing software packages, allowing more challenging inference problems to be solved. BCM represents an efficient one-stop-shop for computational modelers wishing to use sampler-based Bayesian statistics.

Structural and Developmental Disparity in the Tentacles of the Moon Jellyfish Aurelia sp.1

PubMed Central

Gold, David A.; Nakanishi, Nagayasu; Hensley, Nicholai M.; Cozzolino, Kira; Tabatabaee, Mariam; Martin, Michelle; Hartenstein, Volker; Jacobs, David K.

2015-01-01

Tentacles armed with stinging cells (cnidocytes) are a defining trait of the cnidarians, a phylum that includes sea anemones, corals, jellyfish, and hydras. While cnidarian tentacles are generally characterized as structures evolved for feeding and defense, significant variation exists between the tentacles of different species, and within the same species across different life stages and/or body regions. Such diversity suggests cryptic distinctions exist in tentacle function. In this paper, we use confocal and transmission electron microscopy to contrast the structure and development of tentacles in the moon jellyfish, Aurelia species 1. We show that polyp oral tentacles and medusa marginal tentacles display markedly different cellular and muscular architecture, as well as distinct patterns of cellular proliferation during growth. Many structural differences between these tentacle types may reflect biomechanical solutions to different feeding strategies, although further work would be required for a precise mechanistic understanding. However, differences in cell proliferation dynamics suggests that the two tentacle forms lack a conserved mechanism of development, challenging the textbook-notion that cnidarian tentacles can be homologized into a conserved bauplan. PMID:26241309

Structural and Developmental Disparity in the Tentacles of the Moon Jellyfish Aurelia sp.1.

PubMed

Gold, David A; Nakanishi, Nagayasu; Hensley, Nicholai M; Cozzolino, Kira; Tabatabaee, Mariam; Martin, Michelle; Hartenstein, Volker; Jacobs, David K

2015-01-01

Tentacles armed with stinging cells (cnidocytes) are a defining trait of the cnidarians, a phylum that includes sea anemones, corals, jellyfish, and hydras. While cnidarian tentacles are generally characterized as structures evolved for feeding and defense, significant variation exists between the tentacles of different species, and within the same species across different life stages and/or body regions. Such diversity suggests cryptic distinctions exist in tentacle function. In this paper, we use confocal and transmission electron microscopy to contrast the structure and development of tentacles in the moon jellyfish, Aurelia species 1. We show that polyp oral tentacles and medusa marginal tentacles display markedly different cellular and muscular architecture, as well as distinct patterns of cellular proliferation during growth. Many structural differences between these tentacle types may reflect biomechanical solutions to different feeding strategies, although further work would be required for a precise mechanistic understanding. However, differences in cell proliferation dynamics suggests that the two tentacle forms lack a conserved mechanism of development, challenging the textbook-notion that cnidarian tentacles can be homologized into a conserved bauplan.

Humboldt slide - A large shear-dominated retrogressive slope failure

USGS Publications Warehouse

Gardner, J.V.; Prior, D.B.; Field, M.E.

1999-01-01

Humboldt Slide is a large, complex slide zone located on the northern California continental margin. Its three-dimensional architecture has been imaged by a combination of multibeam bathymetry, Huntec Deep-Tow seismic profiling, and sidescan sonar. The slide is interpreted to be Late Pleistocene to early Holocene in age and was caused by a combination of factors. The area of the slide is a local depocenter with high accumulation rates of organic-rich sediment; there has been local steepening of slopes by tectonic uplifts; and the entire area is one of high seismicity. Overall, the failure occurred by retrogressive, shear-dominated, minimum movement apparently as a sequence of events. Failure initially occurred by subsidence extension at the middle of the feature, followed by upslope retrogressive failure and downslope compression, and finally by translational sliding at the top of the slide. Degassing, as evidenced by abundant pockmarks, may have inhibited downslope translation. The slide may still be active, as suggested by offsets in Holocene hemipelagic sediment draped over some of the shear surfaces. Crown cracks occur above the present head of the failure and may represent the next generation of failure.

Source-gated transistors for order-of-magnitude performance improvements in thin-film digital circuits

PubMed Central

Sporea, R. A.; Trainor, M. J.; Young, N. D.; Shannon, J. M.; Silva, S. R. P.

2014-01-01

Ultra-large-scale integrated (ULSI) circuits have benefited from successive refinements in device architecture for enormous improvements in speed, power efficiency and areal density. In large-area electronics (LAE), however, the basic building-block, the thin-film field-effect transistor (TFT) has largely remained static. Now, a device concept with fundamentally different operation, the source-gated transistor (SGT) opens the possibility of unprecedented functionality in future low-cost LAE. With its simple structure and operational characteristics of low saturation voltage, stability under electrical stress and large intrinsic gain, the SGT is ideally suited for LAE analog applications. Here, we show using measurements on polysilicon devices that these characteristics lead to substantial improvements in gain, noise margin, power-delay product and overall circuit robustness in digital SGT-based designs. These findings have far-reaching consequences, as LAE will form the technological basis for a variety of future developments in the biomedical, civil engineering, remote sensing, artificial skin areas, as well as wearable and ubiquitous computing, or lightweight applications for space exploration. PMID:24599023

Connecting Architecture and Implementation

NASA Astrophysics Data System (ADS)

Buchgeher, Georg; Weinreich, Rainer

Software architectures are still typically defined and described independently from implementation. To avoid architectural erosion and drift, architectural representation needs to be continuously updated and synchronized with system implementation. Existing approaches for architecture representation like informal architecture documentation, UML diagrams, and Architecture Description Languages (ADLs) provide only limited support for connecting architecture descriptions and implementations. Architecture management tools like Lattix, SonarJ, and Sotoarc and UML-tools tackle this problem by extracting architecture information directly from code. This approach works for low-level architectural abstractions like classes and interfaces in object-oriented systems but fails to support architectural abstractions not found in programming languages. In this paper we present an approach for linking and continuously synchronizing a formalized architecture representation to an implementation. The approach is a synthesis of functionality provided by code-centric architecture management and UML tools and higher-level architecture analysis approaches like ADLs.

Marginal Bone Loss after Ten Years in an Adult Danish Population: A Radiographic Study.

PubMed

Bahrami, Golnosh; Vaeth, Michael; Wenzel, Ann; Isidor, Flemming

To evaluate marginal bone loss over a 10-year period in individuals and in tooth groups in relation to age and level of marginal bone. In 1997, 616 randomly selected individuals (mean age: 42 years, range: 21-63 years) underwent a full-mouth radiographic survey. In 2008, the survey was repeated in 362 of the same individuals (182 women and 180 men). The marginal bone level of each tooth was measured in mm from the cementoenamel junction to the marginal bone. These measurements were used to calculate marginal bone loss during the 10-year period for individuals and tooth groups in relation to age and to baseline marginal bone level, calculated as the average between measurements in 1997 and 2008 to circumvent regression towards the mean. The average annual marginal bone loss was 0.09 mm (SD ± 0.04 mm) during the 10-year study period. The association between marginal bone loss and baseline marginal bone level was more pronounced in the youngest age group, compared to the other age groups. Molars displayed the most severe bone loss during the study period. Marginal bone loss over a 10-year period is associated with age and baseline marginal bone level. Younger individuals with a reduced marginal bone level were at higher risk for further bone loss. Molars lose marginal bone more rapidly than other tooth groups.

Robust Flutter Margin Analysis that Incorporates Flight Data

NASA Technical Reports Server (NTRS)

Lind, Rick; Brenner, Martin J.

1998-01-01

An approach for computing worst-case flutter margins has been formulated in a robust stability framework. Uncertainty operators are included with a linear model to describe modeling errors and flight variations. The structured singular value, mu, computes a stability margin that directly accounts for these uncertainties. This approach introduces a new method of computing flutter margins and an associated new parameter for describing these margins. The mu margins are robust margins that indicate worst-case stability estimates with respect to the defined uncertainty. Worst-case flutter margins are computed for the F/A-18 Systems Research Aircraft using uncertainty sets generated by flight data analysis. The robust margins demonstrate flight conditions for flutter may lie closer to the flight envelope than previously estimated by p-k analysis.

Early Oral Tongue Squamous Cell Carcinoma: Sampling of Margins From Tumor Bed and Worse Local Control.

PubMed

Maxwell, Jessica H; Thompson, Lester D R; Brandwein-Gensler, Margaret S; Weiss, Bernhard G; Canis, Martin; Purgina, Bibianna; Prabhu, Arpan V; Lai, Chi; Shuai, Yongli; Carroll, William R; Morlandt, Anthony; Duvvuri, Umamaheswar; Kim, Seungwon; Johnson, Jonas T; Ferris, Robert L; Seethala, Raja; Chiosea, Simion I

2015-12-01

Positive margins are associated with poor prognosis among patients with oral tongue squamous cell carcinoma (SCC). However, wide variation exists in the margin sampling technique. To determine the effect of the margin sampling technique on local recurrence (LR) in patients with stage I or II oral tongue SCC. A retrospective study was conducted from January 1, 1986, to December 31, 2012, in 5 tertiary care centers following tumor resection and elective neck dissection in 280 patients with pathologic (p)T1-2 pN0 oral tongue SCC. Analysis was conducted from June 1, 2013, to January 20, 2015. In group 1 (n = 119), tumor bed margins were not sampled. In group 2 (n = 61), margins were examined from the glossectomy specimen, found to be positive or suboptimal, and revised with additional tumor bed margins. In group 3 (n = 100), margins were primarily sampled from the tumor bed without preceding examination of the glossectomy specimen. The margin status (both as a binary [positive vs negative] and continuous [distance to the margin in millimeters] variable) and other clinicopathologic parameters were compared across the 3 groups and correlated with LR. Local recurrence. Age, sex, pT stage, lymphovascular or perineural invasion, and adjuvant radiation treatment were similar across the 3 groups. The probability of LR-free survival at 3 years was 0.9 and 0.8 in groups 1 and 3, respectively (P = .03). The frequency of positive glossectomy margins was lowest in group 1 (9 of 117 [7.7%]) compared with groups 2 and 3 (28 of 61 [45.9%] and 23 of 95 [24.2%], respectively) (P < .001). Even after excluding cases with positive margins, the median distance to the closest margin was significantly narrower in group 3 (2 mm) compared with group 1 (3 mm) (P = .008). The status (positive vs negative) of margins obtained from the glossectomy specimen correlated with LR (P = .007), while the status of tumor bed margins did not. The status of the tumor bed margin was 24% sensitive (95% CI, 16%-34%) and 92% specific (95% CI, 85%-97%) for detecting a positive glossectomy margin. The margin sampling technique affects local control in patients with oral tongue SCC. Reliance on margin sampling from the tumor bed is associated with worse local control, most likely owing to narrower margin clearance and greater incidence of positive margins. A resection specimen-based margin assessment is recommended.

Early Oral Tongue Squamous Cell Carcinoma Sampling of Margins From Tumor Bed and Worse Local Control

PubMed Central

Maxwell, Jessica H.; Thompson, Lester D. R.; Brandwein-Gensler, Margaret S.; Weiss, Bernhard G.; Canis, Martin; Purgina, Bibianna; Prabhu, Arpan V.; Lai, Chi; Shuai, Yongli; Carroll, William R.; Morlandt, Anthony; Duvvuri, Umamaheswar; Kim, Seungwon; Johnson, Jonas T.; Ferris, Robert L.; Seethala, Raja; Chiosea, Simion I.

2017-01-01

IMPORTANCE Positive margins are associated with poor prognosis among patients with oral tongue squamous cell carcinoma (SCC). However, wide variation exists in the margin sampling technique. OBJECTIVE To determine the effect of the margin sampling technique on local recurrence (LR) in patients with stage I or II oral tongue SCC. DESIGN, SETTING, AND PARTICIPANTS A retrospective study was conducted from January 1, 1986, to December 31, 2012, in 5 tertiary care centers following tumor resection and elective neck dissection in 280 patients with pathologic (p)T1-2 pN0 oral tongue SCC. Analysis was conducted from June 1, 2013, to January 20, 2015. INTERVENTIONS In group 1 (n = 119), tumor bed margins were not sampled. In group 2 (n = 61), margins were examined from the glossectomy specimen, found to be positive or suboptimal, and revised with additional tumor bed margins. In group 3 (n = 100), margins were primarily sampled from the tumor bed without preceding examination of the glossectomy specimen. The margin status (both as a binary [positive vs negative] and continuous [distance to the margin in millimeters] variable) and other clinicopathologic parameters were compared across the 3 groups and correlated with LR. MAIN OUTCOMES AND MEASURES Local recurrence. RESULTS Age, sex, pT stage, lymphovascular or perineural invasion, and adjuvant radiation treatment were similar across the 3 groups. The probability of LR-free survival at 3 years was 0.9 and 0.8 in groups 1 and 3, respectively (P = .03). The frequency of positive glossectomy margins was lowest in group 1 (9 of 117 [7.7%]) compared with groups 2 and 3 (28 of 61 [45.9%] and 23 of 95 [24.2%], respectively) (P < .001). Even after excluding cases with positive margins, the median distance to the closest margin was significantly narrower in group 3 (2 mm) compared with group 1 (3 mm) (P = .008). The status (positive vs negative) of margins obtained from the glossectomy specimen correlated with LR (P = .007), while the status of tumor bed margins did not. The status of the tumor bed margin was 24% sensitive (95% CI, 16%-34%) and 92% specific (95% CI, 85%-97%) for detecting a positive glossectomy margin. CONCLUSIONS AND RELEVANCE The margin sampling technique affects local control in patients with oral tongue SCC. Reliance on margin sampling from the tumor bed is associated with worse local control, most likely owing to narrower margin clearance and greater incidence of positive margins. A resection specimen–based margin assessment is recommended. PMID:26225798

The Sedimentary History of Southern Central Crete: Implications for Neogene Uplift

NASA Astrophysics Data System (ADS)

Kröger, K.; Brachert, T. C.; Reuter, M.

2003-04-01

The tectonic setting of Crete was largely extensional since Lower Miocene uplift and exhumation of HP/LT rocks. Erosion of uplifted areas resulted in the deposition of terrestrial to marine sediments in the Messara and Iraclion Basins. There are several concurring models that discuss Late Neogene uplift of the basinal margins. Neogene near shore sediments in the south of the Messara Basin record fault movements contemporaneous to sedimentation and sedimentary input from the hinterland. Therefore they provide information on the paleogeographic situation and the resulting amount of subsidence and uplift of mountain areas since the Upper Miocene. The studied sediments consist of terrestrial to shallow marine, floodplain related sediments of the Upper Miocene Ambelouzos Formation that are overlain by platform limestones of the Upper Miocene Varvara Formation. In the Messara Basin these units are overlain by the Pliocene Kourtes Formation. The stratigraphic architecture of these deposits indicates fragmentation of the basinal margin. Proximal boulder conglomerates and reworked blocks of the Ambelouzos formation indicate fault activity during the deposition of the Varvara Formation. Contents of terrigenous clastics, provided by rivers and distributed by longshore currents, are high in the Ambelouzos and the lower Varvara Formations but decrease rapidly upsection within the Varvara Formation. This indicates drowning of the fault bounded blocks and little topography of the hinterland (Asteroussia Mountains) at that time. The Pliocene marls at the southern margin of the Messara Basin contain lithoclasts of the Upper Miocene limestones and thus indicate uplift of the carbonate platform. The modern topographic elevation of formerly drowned fault bounded blocks requires a minimum uplift of 400m. Main uplift occurred at approximately orthogonal NW-SE and SW-NE striking normal to oblique faults. The present elevation of the Asteroussia Mountains indicates net uplift of at least 1000m since the Early Pliocene. At the Central Iraklion Ridge that separates the Messara and Iraclion Basins a similar history is indicated for the Psiloritis Mountains by fault movements within Neogene near shore sediments and their subsequent drowning. A structural model of the Neogene evolution of Crete therefore has to explain successive phases of uplift and subsidence in an over all extensional setting only slightly oblique to the modern direction of convergence between Africa and the Aegean microplate.

The Bashgumbaz "ophiolites" of SE Pamir (Tajikistan): time constraints for the South Pamir accretion to Eurasia

NASA Astrophysics Data System (ADS)

Zanchetta, Stefano; Worthington, James; Angiolini, Lucia; Zanchi, Andrea

2017-04-01

The Pamir belts, located NW of the Himalaya, formed in response to the Cenozoic collision and indentation of India with Eurasia. Several crustal blocks separated by complex and scarcely studied suture zones form the present day tectonic architecture of the Pamirs. The extreme crustal shortening resulted in strong deformation and bending of pre-existing Paleozoic to Mesozoic orogens. Such deformation hinders straightforward correlations between tectonic terranes of the Himalaya-Tibetan area with their potential continuations through the Pamirs into Afghanistan and Iran. Central and SE Pamir, together with Karakoram and Qiangtang blocks separated from the Gondwana margin in the Early Permian, drifted northward, following the closure of the Paleotethys and other minor oceanic branches, and diachronously collided with Northern Pamir and Tian Shan. The Central and South Pamir are now separated by the poorly known Rushan-Pshart Suture Zone. South Pamir is separated into two units: SE Pamir consists of a Permian to Cenozoic sedimentary succession; SW Pamir is instead made of gigantic basement domes that are in contact with the SE block along crustal scale detachments. In SE Pamir, intensively folded and faulted Permian and Triassic units are unconformably covered by lowermost Jurassic terrigeneous deposits, testifying for Middle to Lower Triassic tectonics related to the Cimmerian orogenic events. Along the contact between the SE and SW Pamir, a small (a few tens of km2 wide) magmatic-metasedimetary unit occurs, reported in literature as the Bashgumbaz ophiolites. They consist of a low-grade metamorphic association of serpentinized harzburgites and gabbros, minor bodies of diorite and plagiogranite, basalts and intermediate volcanic rocks, metasediments, and a flyschoid unit containing olistolithic blocks with Triassic faunas attributed to Central Pamir block. Petrographic and geochemical data suggest a supra-subduction zone affinity for the gabbroic complex. U-Th-Pb dating of zircons from a diorite provides a Carnian crystallization age. Deformation and metamorphism (up to greenschist facies) that affected the Bashgumbaz complex should therefore been placed in the Late Triassic. We suggest that the Bashgumbaz unit formed in a supra-subduction setting and was later underthrusted and then obducted onto the southern margin of the closing Rushan-Pshart ocean. The obduction of the Bashgumbaz ophiolites could be considered as a time-marker for the accretion of the South Pamir terrane to the Eurasian margin.

Deglaciation of the Western Margin of the Barents Sea Ice Sheet - a Swath Bathymetric and Sub-Bottom Seismic Study from Eglacom Nice-Streams Data in the Kveithola Trough

NASA Astrophysics Data System (ADS)

Rebesco, M.; Liu, Y.; Camerlenghi, A.; Winsborrow, M. C.; Laberg, J.; Caburlotto, A.; Diviacco, P.; Accettella, D.; Sauli, C.; Wardell, N.

2010-12-01

IPY Activity N. 367 focusing on Neogene ice streams and sedimentary processes on high- latitude continental margins (NICE-STREAMS) resulted in two coordinated cruises on the adjacent Storfjorden and Kveithola trough-mouth fans in the NW Barents Sea: SVAIS Cruise of BIO Hespérides, summer 2007, and EGLACOM Cruise of Cruise R/V OGS-Explora, summer 2008. The objectives were to acquire a high-resolution set of bathymetric, seismic and sediment core data in order to decipher the Neogene architectural development of the glacially-dominated NW Barents Sea continental margin in response to natural climate change. The paleo-ice streams drained ice from southern Spitsbergen, Spitsbergen Bank, and Bear Island. The short distance from the ice source to the calving front produced a short residence time of ice, and therefore a rapid response to climatic changes. We describe here the EGLACOM data collected within the Kveithola Trough, an E-W trending glacial trough in the NW Barents Sea, NW of the Bear Island. Swath bathymetry shows that the seafloor is characterised by E-W trending mega-scale glacial lineations (MSGL) that record a fast flowing ice stream draining the Svalbard/Barents Sea Ice Sheet (SBIS) during the Last Glacial Maximum (LGM). MSGL are overprinted by transverse sediment ridges about 15 km apart which give rise to a staircase axial profile of the trough. Such transverse ridges are interpreted as grounding-zone wedges (GZW) formed by deposition of unconsolidated, saturated subglacial till during episodic ice stream retreat. Sub-bottom (CHIRP) and multi-channel reflection seismic data show that present-day morphology is largely inherited from the palaeo-seafloor topography at the time of deposition of the transverse ridges, overlain by a draping glaciomarine unit up to over 15 m thick. Our data allow the reconstruction of depositional processes that accompanied the deglaciation of the Spitsbergen Bank area. The sedimentary drape deposited on top of the GZWs which accumulated at a very high rate in the order of 1-1.5 m ka-1 has a potential to preserve a high resolution palaeoclimatic record of the deglaciation and post-glacial condition in this sector of the Barents Sea.

Effect of Margin Designs on the Marginal Adaptation of Zirconia Copings.

PubMed

Habib, Syed Rashid; Al Ajmi, Mohammed Ginan; Al Dhafyan, Mohammed; Jomah, Abdulrehman; Abualsaud, Haytham; Almashali, Mazen

2017-09-01

The aim of this in vitro study was to investigate the effect of Shoulder versus Chamfer margin design on the marginal adaptation of zirconia (Zr) copings. 40 extracted molar teeth were mounted in resin and prepared for zirconia crowns with two margin preparation designs (20=Shoulder and 20=Chamfer). The copings were manufactured by Cercon® (DeguDent GmbH, Germany) using the CAD/CAM system for each tooth. They were tried on each tooth, cemented, thermocycled, re-embedded in resin and were subsequently cross sectioned centrally into two equal mesial and distal halves. They were examined under electron microscope at 200 X magnification and the measurements were recorded at 5 predetermined points in micrometers (µm). The o verall mean marginal gap for the two groups was found to be 206.98+42.78µm with Shoulder margin design (Marginal Gap=199.50+40.72µm) having better adaptation compared to Chamfer (Marginal Gap=214.46+44.85µm). The independent-samples t-test showed a statistically non-significant difference (p=.113) between the means of marginal gap for Shoulder and Chamfer margin designs and the measurements were recorded at 5 predetermined points for the two groups. The Chamfer margin design appeared to offer the same adaptation results as the Shoulder margin design.

Monoclonal Antibody Therapy in Treating Patients With Chronic Lymphocytic Leukemia, Lymphocytic Lymphoma, Acute Lymphoblastic Leukemia, or Acute Myeloid Leukemia

ClinicalTrials.gov

2013-06-03

Extranodal Marginal Zone B-cell Lymphoma of Mucosa-associated Lymphoid Tissue; Nodal Marginal Zone B-cell Lymphoma; Noncontiguous Stage II Marginal Zone Lymphoma; Noncontiguous Stage II Small Lymphocytic Lymphoma; Recurrent Adult Acute Lymphoblastic Leukemia; Recurrent Adult Acute Myeloid Leukemia; Recurrent Marginal Zone Lymphoma; Recurrent Small Lymphocytic Lymphoma; Refractory Chronic Lymphocytic Leukemia; Splenic Marginal Zone Lymphoma; Stage III Marginal Zone Lymphoma; Stage III Small Lymphocytic Lymphoma; Stage IV Marginal Zone Lymphoma; Stage IV Small Lymphocytic Lymphoma

Indigenous women's voices: marginalization and health.

PubMed

Dodgson, Joan E; Struthers, Roxanne

2005-10-01

Marginalization may affect health care delivery. Ways in which indigenous women experienced marginalization were examined. Data from 57 indigenous women (18 to 65 years) were analyzed for themes. Three themes emerged: historical trauma as lived marginalization, biculturalism experienced as marginalization, and interacting within a complex health care system. Experienced marginalization reflected participants' unique perspective and were congruent with previous research. It is necessary for health care providers to assess the detrimental impact of marginalization on the health status of individuals and/or communities.

Architecture Governance: The Importance of Architecture Governance for Achieving Operationally Responsive Ground Systems

NASA Technical Reports Server (NTRS)

Kolar, Mike; Estefan, Jeff; Giovannoni, Brian; Barkley, Erik

2011-01-01

Topics covered (1) Why Governance and Why Now? (2) Characteristics of Architecture Governance (3) Strategic Elements (3a) Architectural Principles (3b) Architecture Board (3c) Architecture Compliance (4) Architecture Governance Infusion Process. Governance is concerned with decision making (i.e., setting directions, establishing standards and principles, and prioritizing investments). Architecture governance is the practice and orientation by which enterprise architectures and other architectures are managed and controlled at an enterprise-wide level

Red (anthocyanic) leaf margins do not correspond to increased phenolic content in New Zealand Veronica spp.

PubMed Central

Hughes, Nicole M.; Smith, William K.; Gould, Kevin S.

2010-01-01

Background and Aims Red or purple coloration of leaf margins is common in angiosperms, and is found in approx. 25 % of New Zealand Veronica species. However, the functional significance of margin coloration is unknown. We hypothesized that anthocyanins in leaf margins correspond with increased phenolic content in leaf margins and/or the leaf entire, signalling low palatability or leaf quality to edge-feeding insects. Methods Five species of Veronica with red leaf margins, and six species without, were examined in a common garden. Phenolic content in leaf margins and interior lamina regions of juvenile and fully expanded leaves was quantified using the Folin–Ciocalteu assay. Proportions of leaf margins eaten and average lengths of continuous bites were used as a proxy for palatability. Key Results Phenolic content was consistently higher in leaf margins compared with leaf interiors in all species; however, neither leaf margins nor more interior tissues differed significantly in phenolic content with respects to margin colour. Mean phenolic content was inversely correlated with the mean length of continuous bites, suggesting effective deterrence of grazing. However, there was no difference in herbivore consumption of red and green margins, and the plant species with the longest continuous grazing patterns were both red-margined. Conclusions Red margin coloration was not an accurate indicator of total phenolic content in leaf margins or interior lamina tissue in New Zealand Veronica. Red coloration was also ineffective in deterring herbivory on the leaf margin, though studies controlling for variations in leaf structure and biochemistry (e.g. intra-specific studies) are needed before more precise conclusions can be drawn. It is also recommended that future studies focus on the relationship between anthocyanin and specific defence compounds (rather than general phenolic pools), and evaluate possible alternative functions of red margins in leaves (e.g. antioxidants, osmotic adjustment). PMID:20145003

Clinical outcome of dedifferentiated liposarcoma in the extremities: A retrospective case series of 7 patients.

PubMed

Kito, Munehisa; Yoshimura, Yasuo; Isobe, Ken'ichi; Aoki, Kaoru; Suzuki, Shuichiro; Tanaka, Atsushi; Okamoto, Masanori; Sano, Kenji; Kato, Hiroyuki

2016-09-01

Wide resection is the generally recommended surgical treatment for dedifferentiated liposarcoma (DDLPS) in the extremities. However, it may be appropriate to distinguish the surgical margin of low-grade atypical lipomatous tumor (ALT)/well-differentiated liposarcoma (WDLPS) area from the high-grade dedifferentiated area, because the low- and high-grade areas can be clearly separated, both radiologically and histologically. This study re-evaluated the details of surgical margin of DDLPS in the extremities, and aimed to investigate the optimal surgical margin and the usefulness of adjuvant therapy for DDLPS in the extremities. Seven patients diagnosed with DDLPS in the extremities and treated between 1995 and 2013 were analyzed. The use of adjuvant therapy before and after surgery was assessed, and the surgical margins for the ALT/WDLPS and dedifferentiated areas were re-evaluated by using the specimens resected at surgery. Subsequently, the recurrence rates, metastatic rates, and oncological outcomes were examined. Four and three patients had wide (adequate wide margin, n = 3; inadequate wide margin, n = 1) and marginal margins for the dedifferentiated area, respectively, while three and four patients had wide (adequate wide margin, n = 2; inadequate wide margin, n = 1) and marginal margins for the ALT/WDLPS area, respectively. Postoperative radiotherapy was performed in three patients with an inadequate wide margin or a marginal margin for the dedifferentiated area. No patient had local recurrence. Distant metastases occurred in two patients. These patients died of their disease. The other five patients were disease-free. The ALT/WDLPS and dedifferentiated areas in the tumor margin may be better to be considered separately in determining the appropriate resection extent for DDLPS in the extremities. Postoperative radiotherapy may provide good local control for cases with a narrow surgical margin. Copyright © 2016 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.

A comparison of glycosaminoglycan distributions, keratan sulphate sulphation patterns and collagen fibril architecture from central to peripheral regions of the bovine cornea

PubMed Central

Ho, Leona T.Y.; Harris, Anthony M.; Tanioka, Hidetoshi; Yagi, Naoto; Kinoshita, Shigeru; Caterson, Bruce; Quantock, Andrew J.; Young, Robert D.; Meek, Keith M.

2014-01-01

This study investigated changes in collagen fibril architecture and the sulphation status of keratan sulphate (KS) glycosaminoglycan (GAG) epitopes from central to peripheral corneal regions. Freshly excised adult bovine corneal tissue was examined as a function of radial position from the centre of the cornea outwards. Corneal thickness, tissue hydration, hydroxyproline content, and the total amount of sulphated GAG were all measured. High and low-sulphated epitopes of keratan sulphate were studied by immunohistochemistry and quantified by ELISA. Chondroitin sulphate (CS) and dermatan sulphate (DS) distributions were observed by immunohistochemistry following specific enzyme digestions. Electron microscopy and X-ray fibre diffraction were used to ascertain collagen fibril architecture. The bovine cornea was 1021 ± 5.42 μm thick at its outer periphery, defined as 9–12 mm from the corneal centre, compared to 844 ± 8.10 μm at the centre. The outer periphery of the cornea was marginally, but not significantly, more hydrated than the centre (H = 4.3 vs. H = 3.7), and was more abundant in hydroxyproline (0.12 vs. 0.06 mg/mg dry weight of cornea). DMMB assays indicated no change in the total amount of sulphated GAG across the cornea. Immunohistochemistry revealed the presence of both high- and low-sulphated epitopes of KS, as well as DS, throughout the cornea, and CS only in the peripheral cornea before the limbus. Quantification by ELISA, disclosed that although both high- and low-sulphated KS remained constant throughout stromal depth at different radial positions, high-sulphated epitopes remained constant from the corneal centre to outer-periphery, whereas low-sulphated epitopes increased significantly. Both small angle X-ray diffraction and TEM analysis revealed that collagen fibril diameter remained relatively constant until the outer periphery was reached, after which fibrils became more widely spaced (from small angle x-ray diffraction analysis) and of larger diameter as they approached the sclera. Depth-profiled synchrotron microbeam analyses showed that, at different radial positions from the corneal centre outwards, fibril diameter was greater superficially than in deeper stromal regions. The interfibrillar spacing was also higher at mid-depth in the stroma than it was in anterior and posterior stromal regions. Collagen fibrils in the bovine cornea exhibited a fairly consistent spacing and diameter from the corneal centre to the 12 mm radial position, after which a significant increase was seen. While the constancy of the overall sulphation levels of proteoglycans in the cornea may correlate with the fibrillar architecture, there was no correlation between the latter and the distribution of low-sulphated KS. PMID:25019467

Worst-Case Flutter Margins from F/A-18 Aircraft Aeroelastic Data

NASA Technical Reports Server (NTRS)

Lind, Rick; Brenner, Marty

1997-01-01

An approach for computing worst-case flutter margins has been formulated in a robust stability framework. Uncertainty operators are included with a linear model to describe modeling errors and flight variations. The structured singular value, micron, computes a stability margin which directly accounts for these uncertainties. This approach introduces a new method of computing flutter margins and an associated new parameter for describing these margins. The micron margins are robust margins which indicate worst-case stability estimates with respect to the defined uncertainty. Worst-case flutter margins are computed for the F/A-18 SRA using uncertainty sets generated by flight data analysis. The robust margins demonstrate flight conditions for flutter may lie closer to the flight envelope than previously estimated by p-k analysis.

Marginal and happy? The need for uniqueness predicts the adjustment of marginal immigrants.

PubMed

Debrosse, Régine; de la Sablonnière, Roxane; Rossignac-Milon, Maya

2015-12-01

Marginalization is often presented as the strategy associated with the worst adjustment for immigrants. This study identifies a critical variable that buffers marginal immigrants from the negative effects of marginalization on adjustment: The need for uniqueness. In three studies, we surveyed immigrants recruited on university campuses (n = 119, n = 116) and in the field (n = 61). Among marginal immigrants, a higher need for uniqueness predicted higher self-esteem (Study 1), affect (Study 2), and life satisfaction (Study 3), and marginally higher happiness (Study 2) and self-esteem (Study 3). No relationship between the need for uniqueness and adjustment was found among non-marginal immigrants. The adaptive value of the need for uniqueness for marginal immigrants is discussed. © 2015 The British Psychological Society.

Exploring the Subtleties of Inverse Probability Weighting and Marginal Structural Models.

PubMed

Breskin, Alexander; Cole, Stephen R; Westreich, Daniel

2018-05-01

Since being introduced to epidemiology in 2000, marginal structural models have become a commonly used method for causal inference in a wide range of epidemiologic settings. In this brief report, we aim to explore three subtleties of marginal structural models. First, we distinguish marginal structural models from the inverse probability weighting estimator, and we emphasize that marginal structural models are not only for longitudinal exposures. Second, we explore the meaning of the word "marginal" in "marginal structural model." Finally, we show that the specification of a marginal structural model can have important implications for the interpretation of its parameters. Each of these concepts have important implications for the use and understanding of marginal structural models, and thus providing detailed explanations of them may lead to better practices for the field of epidemiology.

Magnetic tunnel junction based spintronic logic devices

NASA Astrophysics Data System (ADS)

Lyle, Andrew Paul

The International Technology Roadmap for Semiconductors (ITRS) predicts that complimentary metal oxide semiconductor (CMOS) based technologies will hit their last generation on or near the 16 nm node, which we expect to reach by the year 2025. Thus future advances in computational power will not be realized from ever-shrinking device sizes, but rather by 'outside the box' designs and new physics, including molecular or DNA based computation, organics, magnonics, or spintronic. This dissertation investigates magnetic logic devices for post-CMOS computation. Three different architectures were studied, each relying on a different magnetic mechanism to compute logic functions. Each design has it benefits and challenges that must be overcome. This dissertation focuses on pushing each design from the drawing board to a realistic logic technology. The first logic architecture is based on electrically connected magnetic tunnel junctions (MTJs) that allow direct communication between elements without intermediate sensing amplifiers. Two and three input logic gates, which consist of two and three MTJs connected in parallel, respectively were fabricated and are compared. The direct communication is realized by electrically connecting the output in series with the input and applying voltage across the series connections. The logic gates rely on the fact that a change in resistance at the input modulates the voltage that is needed to supply the critical current for spin transfer torque switching the output. The change in resistance at the input resulted in a voltage margin of 50--200 mV and 250--300 mV for the closest input states for the three and two input designs, respectively. The two input logic gate realizes the AND, NAND, NOR, and OR logic functions. The three input logic function realizes the Majority, AND, NAND, NOR, and OR logic operations. The second logic architecture utilizes magnetostatically coupled nanomagnets to compute logic functions, which is the basis of Magnetic Quantum Cellular Automata (MQCA). MQCA has the potential to be thousands of times more energy efficient than CMOS technology. While interesting, these systems are academic unless they can be interfaced into current technologies. This dissertation pushed past a major hurdle by experimentally demonstrating a spintronic input/output (I/O) interface for the magnetostatically coupled nanomagnets by incorporating MTJs. This spintronic interface allows individual nanomagnets to be programmed using spin transfer torque and read using magneto resistance structure. Additionally the spintronic interface allows statistical data on the reliability of the magnetic coupling utilized for data propagation to be easily measured. The integration of spintronics and MQCA for an electrical interface to achieve a magnetic logic device with low power creates a competitive post-CMOS logic device. The final logic architecture that was studied used MTJs to compute logic functions and magnetic domain walls to communicate between gates. Simulations were used to optimize the design of this architecture. Spin transfer torque was used to compute logic function at each MTJ gate and was used to drive the domain walls. The design demonstrated that multiple nanochannels could be connected to each MTJ to realize fan-out from the logic gates. As a result this logic scheme eliminates the need for intermediate reads and conversions to pass information from one logic gate to another.

--No Title--

Science.gov Websites

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Comparison of histologic margin status in low-grade cutaneous and subcutaneous canine mast cell tumours examined by radial and tangential sections.

PubMed

Dores, C B; Milovancev, M; Russell, D S

2018-03-01

Radial sections are widely used to estimate adequacy of excision in canine cutaneous mast cell tumours (MCTs); however, this sectioning technique estimates only a small fraction of total margin circumference. This study aimed to compare histologic margin status in grade II/low grade MCTs sectioned using both radial and tangential sectioning techniques. A total of 43 circumferential margins were evaluated from 21 different tumours. Margins were first sectioned radially, followed by tangential sections. Tissues were examined by routine histopathology. Tangential margin status differed in 10 of 43 (23.3%) margins compared with their initial status on radial section. Of 39 margins, 9 (23.1%) categorized as histologic tumour-free margin (HTFM) >0 mm were positive on tangential sectioning. Tangential sections detected a significantly higher proportion of positive margins relative to radial sections (exact 2-tailed P-value = .0215). The HTFM was significantly longer in negative tangential margins than positive tangential margins (mean 10.1 vs 3.2 mm; P = .0008). A receiver operating characteristic curve comparing HTFM and tangentially negative margins found an area under the curve of 0.83 (95% confidence interval: 0.71-0.96). Although correct classification peaked at the sixth cut-point of HTFM ≥1 mm, radial sections still incorrectly classified 50% of margins as lacking tumour cells. Radial sections had 100% specificity for predicting negative tangential margins at a cut-point of 10.9 mm. These data indicate that for low grade MCTs, HTFMs >0 mm should not be considered completely excised, particularly when HTFM is <10.9 mm. This will inform future studies that use HTFM and overall excisional status as dependent variables in multivariable prognostic models. © 2017 John Wiley & Sons Ltd.

[The economic margins of activities of a bovine practitioner on dairy farms].

PubMed

van Genugten, A J M; van Haaften, J A; Hogeveen, H

2011-11-01

Because of lower margins and market liberalisation veterinarians and farmers are increasingly negotiating rates. Therefore, the margins of veterinarians are under pressure. In addition, the sales if drugs, performance of operations or giving of advice are more and more separated. These developments give veterinarians uncertainty about the profitability of their activities for dairy farmers. Not much is known about margins on veterinary activities on dairy farms. Moreover, it is interesting to see how much margins of the bovine practitioner differ between veterinary practises and dairy farms. In this study, invoices for bovine activities of 14 veterinary practises were combined with milk production registration data of the dairy farms of these practices. This way, the gross margin per bovine practitioner could be studied for the different veterinary practise. Moreover the relation between gross margin and specification of the veterinary practise could be studied. Finally, the gross margin per dairy farm and the factors that influenced this gross margin were studied. The most important result was the observation that the gross margin per bovine practitioner was dependent on the number of dairy farms per practitioner, the margin on drugs and the region of the veterinary practise. The size of the veterinary practise, the share of the dairy farming within the practise and the source of the gross margin (drugs, time or operations) did not influence the gross margin. Variables that explained the gross margin per dairy farm were, amongst others, the number of dairy cows, the milk production level of the farms and participation in PIR-DAP (a system to support the veterinarians herd health and management program). There is no relation of gross margin per dairy farm and the veterinary practise or region.

Rituximab and Dexamethasone in Treating Patients With Low-Grade Non-Hodgkin Lymphoma

ClinicalTrials.gov

2017-04-14

Contiguous Stage II Grade 1 Follicular Lymphoma; Contiguous Stage II Grade 2 Follicular Lymphoma; Contiguous Stage II Marginal Zone Lymphoma; Cutaneous B-cell Non-Hodgkin Lymphoma; Extranodal Marginal Zone B-cell Lymphoma of Mucosa-associated Lymphoid Tissue; Nodal Marginal Zone B-cell Lymphoma; Noncontiguous Stage II Grade 1 Follicular Lymphoma; Noncontiguous Stage II Grade 2 Follicular Lymphoma; Noncontiguous Stage II Marginal Zone Lymphoma; Recurrent Grade 1 Follicular Lymphoma; Recurrent Grade 2 Follicular Lymphoma; Recurrent Marginal Zone Lymphoma; Splenic Marginal Zone Lymphoma; Stage I Grade 1 Follicular Lymphoma; Stage I Grade 2 Follicular Lymphoma; Stage I Marginal Zone Lymphoma; Stage III Grade 1 Follicular Lymphoma; Stage III Grade 2 Follicular Lymphoma; Stage III Marginal Zone Lymphoma; Stage IV Grade 1 Follicular Lymphoma; Stage IV Grade 2 Follicular Lymphoma; Stage IV Marginal Zone Lymphoma; Waldenstrom Macroglobulinemia

The Bowser and Sustut Basins, Northern British Columbia, Canada: Insights From Analysis of Magnetic Anomaly Data.

NASA Astrophysics Data System (ADS)

Baker, J.; Lowe, C.

2005-12-01

The Bowser and Sustut basins occupy an area of more than 60,000 km2 in northern British Columbia, Canada. They comprise three, dominantly sedimentary, stratigraphic successions, in part overlapping in age: the Bowser Lake Group, the Skeena Group, and the Sustut Group. These three successions overlie arc volcanic and volcaniclastic strata of Stikinia, an allochtonous island arc terrane that accreted to the western margin of North America in the Early Jurassic to early Middle Jurassic. All three basin successions and underlying Stikinia were deformed during development of a thin-skinned fold and thrust belt (the Skeena Fold and Thrust Belt) in Cretaceous and possibly into earliest Tertiary time. Recently, the basins have been the focus of intense geological studies which have resulted in major revisions to the stratigraphic and structural framework of the basins and demonstrated that they have significantly higher petroleum potential than had been previously recognized. To advance these new findings further requires better imaging of the three-dimensional geometry and architecture of the basins. In this study we harness existing magnetic anomaly data to provide the first quantitative estimates of sedimentary thickness across the entire extents of both basins. Our results, which are in general in accord with geological interpretations, indicate that basin-fill is relatively thin and fairly uniform in the Sustut Basin (2.5-3 km), but highly variable in the Bowser Basin, ranging from less than 2 km to more than 6 km. Overall, sedimentary fill is thicker in the northern half of Bowser Basin compared to the south and is typically less than 2 km near the basins northern, western and southern margins. In addition, we demonstrate how a large, buried intrusion beneath the northeast part of Bowser Basin can account for an observed magnetic anomaly and explain the high coalification gradients and localized high maturation levels of the overlying sedimentary rocks. Neither of the latter can be adequately explained by the estimated burial depths. We delineate at least one regionally extensive fault that is more than 150 km long and that cuts basement of Bowser Basin. The fault may have facilitated migration of hydrocarbons sourced in the basement into Bowser Basin. We show how magnetic data can be used to refine isotopically-determined ages of the late Tertiary Maitland Volcanics that overlap the sedimentary fill and to demonstrate that the volcanism must have been episodic and not the result of a single eruptive event. Collectively, these findings provide new insights into the crustal architecture of northern British Columbia and important constraints for geodynamic models of the basins evolution and their resource potential.

CO2 laser versus cold steel margin analysis following endoscopic excision of glottic cancer

PubMed Central

2014-01-01

Objective To compare the suitability of CO2 laser with steel instruments for margin excision in transoral laser microsurgery. Methods Prospective randomized blinded study. Patients with glottic cancer undergoing laser resection were randomized to margin excision by either steel instruments or CO2 laser. Margins were analyzed for size, interpretability and degree of artifact by a pathologist who was blinded to technique. Results 45 patients were enrolled in the study with 226 total margins taken. 39 margins taken by laser had marked artifact and 0 were uninterpretable. 20 margins taken by steel instruments had marked artifact, and 2 were uninterpretable. Controlling for margin size, the laser technique was associated with increasing degrees of margin artifact (p = 0.210), but there was no difference in crude rates of uninterpretability (p = 0.24). Conclusion Laser margin excision is associated with a greater degree of artifact than steel instrument excision, but was not associated with higher rate of uninterpretability. PMID:24502856

Independent Predictors of Prognosis Based on Oral Cavity Squamous Cell Carcinoma Surgical Margins.

PubMed

Buchakjian, Marisa R; Ginader, Timothy; Tasche, Kendall K; Pagedar, Nitin A; Smith, Brian J; Sperry, Steven M

2018-05-01

Objective To conduct a multivariate analysis of a large cohort of oral cavity squamous cell carcinoma (OCSCC) cases for independent predictors of local recurrence (LR) and overall survival (OS), with emphasis on the relationship between (1) prognosis and (2) main specimen permanent margins and intraoperative tumor bed frozen margins. Study Design Retrospective cohort study. Setting Tertiary academic head and neck cancer program. Subjects and Methods This study included 426 patients treated with OCSCC resection between 2005 and 2014 at University of Iowa Hospitals and Clinics. Patients underwent excision of OCSCC with intraoperative tumor bed frozen margin sampling and main specimen permanent margin assessment. Multivariate analysis of the data set to predict LR and OS was performed. Results Independent predictors of LR included nodal involvement, histologic grade, and main specimen permanent margin status. Specifically, the presence of a positive margin (odds ratio, 6.21; 95% CI, 3.3-11.9) or <1-mm/carcinoma in situ margin (odds ratio, 2.41; 95% CI, 1.19-4.87) on the main specimen was an independent predictor of LR, whereas intraoperative tumor bed margins were not predictive of LR on multivariate analysis. Similarly, independent predictors of OS on multivariate analysis included nodal involvement, extracapsular extension, and a positive main specimen margin. Tumor bed margins did not independently predict OS. Conclusion The main specimen margin is a strong independent predictor of LR and OS on multivariate analysis. Intraoperative tumor bed frozen margins do not independently predict prognosis. We conclude that emphasis should be placed on evaluating the main specimen margins when estimating prognosis after OCSCC resection.

[Radiological control intraoperatory of a surgical piece in non palpable breast lesions].

PubMed

Ruvalcaba Limón, Eva; Espejo Fonseca, Ruby; Bautista Piña, Verónica; Madero Preciado, Luis; Capurso Garcia, Marino; Serratos Garduño, José Eduardo; Hohenstein, Fernando Guisa; Rodríguez Cuevas, Sergio

2009-09-01

nonconcrete the mammary injuries are frequent in programs of detection of breast cancer, estereotaxic or ecographic marking is required to realize its split. The intrasurgical radiation control of the surgical piece is indispensable to evaluate the margins of the mammary cancer. to determine the effectiveness of the intrasurgical radiation control of the surgical piece in nonconcrete mammary injuries to diminish the surgical reinterventions to extend margins. women with nonconcrete mammary injuries to those who biopsy by split became, previous marking and intraoperating radiation control of the surgical piece to value margins (suitable margin the same or major of 10 mm, smaller inadequate margin of 10 mm). Intrasurgical reesicion in inadequate radiological margins became. The demographic characteristics, masto-ecographics images, histopathology of the injuries and the radiological-histopatol6gica correlation of the margins studied. Cross-sectional, prospective and descriptive study. 103 patients with 113 nonconcrete mammary injuries included themselves, with age average of 51,35 (32-73) years. In all the injuries the intrasurgical radiation control became of the surgical piece. The prevalence of mammary cancer was of 28.3% (32/113), that corresponds to stellar images (42.8%), suspicious microcalcifications with density (39.2%), microcalcifications (31.2%) and nodules (20%). Of the 32 cancers, 16 had inadequate radiological margins that required intraoperating reescision; suitable histopatologic margins in 100% were obtained (16/16). The 16 (62.5%) cancers without intraoperating reescisi6n by suitable radiological margins had suitable histopatologic margins and 37.5% (6/16) inadequate ones that required surgical reinterventionn to control the margins. The discrepancy between margins was related to microcalcifications in 83.3% of the injuries. the intrasurgical radiation control of the surgical piece is effective to evaluate margins; the intrasurgical reescisión changed inadequate margins to suitable in 50% (16/32) of the cancers; only 18.7% (6/32) of the total of cases required another surgery to control the margins.

From a collage of microplates to stable continental crust - an example from Precambrian Europe

NASA Astrophysics Data System (ADS)

Korja, Annakaisa

2013-04-01

Svecofennian orogen (2.0-1.7 Ga) comprises the oldest undispersed orogenic belt on Baltica and Eurasian plate. Svecofennian orogenic belt evolved from a series of short-lived terrane accretions around Baltica's Archean nucleus during the formation of the Precambrian Nuna supercontinent. Geological and geophysical datasets indicate W-SW growth of Baltica with NE-ward dipping subduction zones. The data suggest a long-lived retreating subduction system in the southwestern parts whereas in the northern and central parts the northeasterly transport of continental fragments or microplates towards the continental nucleus is also documented. The geotectonic environment resembles that of the early stages of the Alpine-Himalayan or Indonesian orogenic system, in which dispersed continental fragments, arcs and microplates have been attached to the Eurasian plate margin. Thus the Svecofennian orogeny can be viewed as proxy for the initial stages of an internal orogenic system. Svecofennian orogeny is a Paleoproterozoic analogue of an evolved orogenic system where terrane accretion is followed by lateral spreading or collapse induced by change in the plate architecture. The exposed parts are composed of granitoid intrusions as well as highly deformed supracrustal units. Supracrustal rocks have been metamorphosed in LP-HT conditions in either paleo-lower-upper crust or paleo-upper-middle crust. Large scale seismic reflection profiles (BABEL and FIRE) across Baltica image the crust as a collage of terranes suggesting that the bedrock has been formed and thickened in sequential accretions. The profiles also image three fold layering of the thickened crust (>55 km) to transect old terrane boundaries, suggesting that the over-thickened bedrock structures have been rearranged in post-collisional spreading and/or collapse processes. The middle crust displays typical large scale flow structures: herringbone and anticlinal ramps, rooted onto large scale listric surfaces also suggestive of spreading. Close to the original ocean-continent plate boundary, in the core of the Svecofennian orogen, the thickened accretionary crust carries pervasive stretching lineations at surface and seismic vp-velocity anisotropy in the crust. The direction of spreading and crustal flow seems to be diverted by shapes of the pre-existing boundaries. It is concluded that lateral spreading and midcrustal flow not only rearrange the bedrock architecture but also stabilize the young accreted continental crust in emerging internal orogenic systems. Pre-existing microplate/terrane boundaries will affect the final architecture of the orogenic belt.

Stratigraphic architecture of hydromagmatic volcanoes that have undergone vent migration: a review of Korean case studies

NASA Astrophysics Data System (ADS)

Sohn, Y.

2011-12-01

Recent studies show that the architecture of hydromagmatic volcanoes is far more complex than formerly expected. A number of external factors, such as paleohydrology and tectonics, in addition to magmatic processes are thought to play a role in controlling the overall characteristics and architecture of these volcanoes. One of the main consequences of these controls is the migration of the active vent during eruption. Case studies of hydromagmatic volcanoes in Korea show that those volcanoes that have undergone vent migration are characterized by superposition or juxtaposition of multiple rim deposits of partial tuff rings and/or tuff cones that have contrasting lithofacies characteristics, bed attitudes, and paleoflow directions. Various causes of vent migration are inferred from these volcanoes. Large-scale collapse of fragile substrate is interpreted to have caused vent migration in the Early Pleistocene volcanoes of Jeju Island, which were built upon still unconsolidated continental shelf sediments. Late Pleistocene to Holocene volcanoes, which were built upon a stack of rigid, shield-forming lava flows, lack features due to large-scale substrate collapse and have generally simple and circular morphologies either of a tuff ring or of a tuff cone. However, ~600 m shift of the eruptive center is inferred from one of these volcanoes (Ilchulbong tuff cone). The vent migration in this volcano is interpreted to have occurred because the eruption was sourced by multiple magma batches with significant eruptive pauses in between. The Yangpori diatreme in a Miocene terrestrial half-graben basin in SE Korea is interpreted to be a subsurface equivalent of a hydromagmatic volcano that has undergone vent migration. The vent migration here is inferred to have had both vertical and lateral components and have been caused by an abrupt tectonic activity near the basin margin. In all these cases, rimbeds or diatreme fills derived from different source vents are bounded by either prominent or subtle, commonly laterally extensive truncation surfaces or stratigraphic discontinuities. Careful documentation of these surfaces and discontinuities thus appears vital to proper interpretation of eruption history, morphologic evolution, and even deep-seated magmatic processes of a hydromagmatic volcano. In this respect, the technique known as 'allostratigraphy' appears useful in mapping, correlation, and interpretation of many hydrovolcanic edifices and sequences.

Towards a morphogenetic classification of eskers: Implications for modelling ice sheet hydrology

NASA Astrophysics Data System (ADS)

Perkins, Andrew J.; Brennand, Tracy A.; Burke, Matthew J.

2016-02-01

Validations of paleo-ice sheet hydrological models have used esker spacing as a proxy for ice tunnel density. Changes in crest type (cross-sectional shape) along esker ridges have typically been attributed to the effect of changing subglacial topography on hydro- and ice-dynamics and hence subglacial ice-tunnel shape. These claims assume that all eskers formed in subglacial ice tunnels and that all major subglacial ice tunnels produced a remnant esker. We identify differences in geomorphic context, sinuosity, cross-sectional shape, and sedimentary architecture by analysing eskers formed at or near the margins of the last Cordilleran Ice Sheet on British Columbia's southern Fraser Plateau, and propose a morphogenetic esker classification. Three morphogenetic types and 2 subtypes of eskers are classified based on differences in geomorphic context, ridge length, sinuosity, cross-sectional shape and sedimentary architecture using geophysical techniques and sedimentary exposures; they largely record seasonal meltwater flows and glacial lake outburst floods (GLOFs) through sub-, en- and supraglacial meltwater channels and ice-walled canyons. General principles extracted from these interpretations are: 1) esker ridge crest type and sinuosity strongly reflect meltwater channel type. Eskers formed in subglacial conduits are likely to be round-crested with low sinuosity (except where controlled by ice structure or modified by surging) and contain faults associated with flank collapse. Eskers formed near or at the ice surface are more likely to be sharp-crested, highly sinuous, and contain numerous faults both under ridge crest-lines and in areas of flank collapse. 2) Esker ridges containing numerous flat-crested reaches formed directly on the land-surface in ice-walled canyons (unroofed ice tunnels) or in ice tunnels at atmospheric pressure, and therefore likely record thin or dead ice. 3) Eskers containing macroforms exhibiting headward and downflow growth likely record flood-scale flows (possibly GLOFs where a lake can be inferred). These conclusions suggest that esker crest type, sinuosity and geomorphic context, when understood along with sedimentary architecture, largely reflect formational position with respect to the ice-surface. Reconstructions of ice sheet hydrology need to account for variation in esker morphology because basing hydrodynamic inferences on the presence or absence of an esker alone ignores encoded differences in water source, supply, flow magnitude and frequency, and conduit position.

30 CFR 204.3 - What alternatives are available for marginal properties?

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 2 2010-07-01 2010-07-01 false What alternatives are available for marginal... MINERALS REVENUE MANAGEMENT ALTERNATIVES FOR MARGINAL PROPERTIES General Provisions § 204.3 What alternatives are available for marginal properties? If you have production from a marginal property, MMS and...

Examining the margins: a concept analysis of marginalization.

PubMed

Vasas, Elyssa B

2005-01-01

The aim of this analysis is to explore the concept of social marginalization for the purpose of concept development. Specifically, the article intends to clarify the relationship between health disparities and marginalization and generate knowledge about working with people who are socially marginalized. Concept development evolved from the critical analysis of relevant literature generated through searches of nursing and social science databases. Literature was organized thematically and themes related to marginalization as a social process were included and analyzed. The article explores the challenges of using marginalization as an independent concept and suggests areas for future inquiry and research.

The effect of porcelain firing and type of finish line on the marginal fit of zirconia copings.

PubMed

Vojdani, Mahroo; Safari, Anahita; Mohaghegh, Mina; Pardis, Soheil; Mahdavi, Farideh

2015-06-01

Although all-ceramic restorations are broadly used, there is a lack of information concerning how their fit is affected by fabrication procedure and marginal configuration. The purpose of this study was to evaluate the marginal fit of zirconia CAD/CAM ceramic crowns before and after porcelain firing. The influence of finish line configuration on the marginal fit was also evaluated. Twenty standardized zirconia CAD/CAM copings were fabricated for chamfer and shoulder finish line designs (n=10). The marginal fit of specimens was measured on 18 points, marked on the master metal die by using a digital microscope. After the crowns were finalized by porcelain veneering, the measurements of marginal fit were performed again. The means and standard deviations were calculated and data were analyzed using student's t-test and paired t-test (α=0.05). There were significant differences between marginal fit of chamfer and shoulder finish line groups before and after porcelain firing (p= 0.014 and p= 0.000, respectively). The marginal gap of copings with shoulder finish line was significantly smaller than those with chamfer configuration (p= 0.000), but there were no significant differences between the two marginal designs, after porcelain firing (p= 0.341). Porcelain veneering was found to have a statistically significant influence on the marginal fit of zirconia CAD/CAM crowns. Both margin configurations showed marginal gaps that were within a reported clinically acceptable range of marginal discrepancy.

Continental transform margins : state of art and future milestones

NASA Astrophysics Data System (ADS)

Basile, Christophe

2010-05-01

Transform faults were defined 45 years ago as ‘a new class of fault' (Wilson, 1965), and transform margins were consequently individualized as a new class of continental margins. While transform margins represent 20 to 25 % of the total length of continent-ocean transitions, they were poorly studied, especially when compared with the amount of data, interpretations, models and conceptual progress accumulated on divergent or convergent continental margins. The best studied examples of transform margins are located in the northern part of Norway, south of South Africa, in the gulf of California and on both sides of the Equatorial Atlantic. Here is located the Côte d'Ivoire - Ghana margin, where the more complete data set was acquired, based on numerous geological and geophysical cruises, including ODP Leg 159. The first models that encompassed the structure and evolution of transform margins were mainly driven by plate kinematic reconstructions, and evidenced the diachronic end of tectonic activity and the non-cylindrical character of these margins, with a decreasing strike-slip deformation from the convex to the concave divergent-transform intersections. Further thermo-mechanical models were more specifically designed to explain the vertical displacements along transform margins, and especially the occurrence of high-standing marginal ridges. These thermo-mechanical models involved either heat transfer from oceanic to continental lithospheres across the transform faults or tectonically- or gravity-driven mass transfer in the upper crust. These models were far from fully fit observations, and were frequently dedicated to specific example, and not easily generalizable. Future work on transform continental margins may be expected to fill some scientific gaps, and the definition of working directions can benefit from the studies dedicated to other types of margins. At regional scale the structural and sedimentological variability of transform continental margins has to be emphasized. There is not only one type of transform margins, but as for divergent margins huge changes from one margin to another in both structure and evolution. Multiple types have to be evidenced together with the various parameters that should control the variability. As for divergent margins, special attention should be paid to conjugated transform margins as a tool to assess symmetrical / asymmetrical processes in the oceanic opening. Attention should also be focused on the three-dimensional structure of the intersections between transform and divergent margins, such as the one where the giant oil field Jubilee was recently discovered. There is almost no 3D data available in these area, and their structures still have to be described. An other key point to develop is the mechanical behavior of the lithosphere in and in the vicinity of transform margins. The classical behaviors (isostasy, elastic flexure) have be tested extensively. The localization of the deformation by the transform fault, and the coupling of continental and oceanic lithosphere across the transform fault have to be adressed to understand the evolution of these margins. Again as for divergent margins, new concepts are needed to explain the variations in the post-rift and post-transform subsidence, that can not always be explained by classical subsidence models. But the most remarkable advance in our understanding of transform margins may be related to the study of interactions between the lithosphere and adjacent envelops : deep interactions with the mantle, as underplating, tectonic erosion, or possible lateral crustal flow ; surficial interactions between structural evolution, erosion and sedimentation processes in transform margins may affect the topography and bathymetry, thus the oceanic circulation with possible effects on regional and global climate.

Applied Time Domain Stability Margin Assessment for Nonlinear Time-Varying Systems

NASA Technical Reports Server (NTRS)

Kiefer, J. M.; Johnson, M. D.; Wall, J. H.; Dominguez, A.

2016-01-01

The baseline stability margins for NASA's Space Launch System (SLS) launch vehicle were generated via the classical approach of linearizing the system equations of motion and determining the gain and phase margins from the resulting frequency domain model. To improve the fidelity of the classical methods, the linear frequency domain approach can be extended by replacing static, memoryless nonlinearities with describing functions. This technique, however, does not address the time varying nature of the dynamics of a launch vehicle in flight. An alternative technique for the evaluation of the stability of the nonlinear launch vehicle dynamics along its trajectory is to incrementally adjust the gain and/or time delay in the time domain simulation until the system exhibits unstable behavior. This technique has the added benefit of providing a direct comparison between the time domain and frequency domain tools in support of simulation validation. This technique was implemented by using the Stability Aerospace Vehicle Analysis Tool (SAVANT) computer simulation to evaluate the stability of the SLS system with the Adaptive Augmenting Control (AAC) active and inactive along its ascent trajectory. The gains for which the vehicle maintains apparent time-domain stability defines the gain margins, and the time delay similarly defines the phase margin. This method of extracting the control stability margins from the time-domain simulation is relatively straightforward and the resultant margins can be compared to the linearized system results. The sections herein describe the techniques employed to extract the time-domain margins, compare the results between these nonlinear and the linear methods, and provide explanations for observed discrepancies. The SLS ascent trajectory was simulated with SAVANT and the classical linear stability margins were evaluated at one second intervals. The linear analysis was performed with the AAC algorithm disabled to attain baseline stability margins. At each time point, the system was linearized about the current operating point using Simulink's built-in solver. Each linearized system in time was evaluated for its rigid-body gain margin (high frequency gain margin), rigid-body phase margin, and aero gain margin (low frequency gain margin) for each control axis. Using the stability margins derived from the baseline linearization approach, the time domain derived stability margins were determined by executing time domain simulations in which axis-specific incremental gain and phase adjustments were made to the nominal system about the expected neutral stability point at specific flight times. The baseline stability margin time histories were used to shift the system gain to various values around the zero margin point such that a precise amount of expected gain margin was maintained throughout flight. When assessing the gain margins, the gain was applied starting at the time point under consideration, thereafter following the variation in the margin found in the linear analysis. When assessing the rigid-body phase margin, a constant time delay was applied to the system starting at the time point under consideration. If the baseline stability margins were correctly determined via the linear analysis, the time domain simulation results should contain unstable behavior at certain gain and phase values. Examples will be shown from repeated simulations with variable added gain and phase lag. Faithfulness of margins calculated from the linear analysis to the nonlinear system will be demonstrated.

Carfilzomib With or Without Rituximab in the Treatment of Waldenstrom Macroglobulinemia or Marginal Zone Lymphoma

ClinicalTrials.gov

2018-02-05

Marginal Zone Lymphoma; Recurrent Marginal Zone Lymphoma; Recurrent Waldenstrom Macroglobulinemia; Refractory Marginal Zone Lymphoma; Refractory Waldenstrom Macroglobulinemia; Waldenstrom Macroglobulinemia

Turbidite systems: State of the art and future directions

USGS Publications Warehouse

Normark, W.R.; Posamentier, H.; Mutti, E.

1993-01-01

The study of turbidite systems covering a wide range of physical scales has led to confus ion regarding the use of certain key terms and hence a breakdown in communication between workers involved in turbidite research. There are three fundamentally different scales and types of observations derived from the study of outcrop data (ancient systems), high-resolution seismic reflection and side scan sonar data (modern systems), and multichannel seismic reflection data (modern and older buried systems). Despite the variability of scale the same terms are used to describe features that may have little in common. Consequently, turbidite system terminology has become imprecise and even misleading in some cases, thus providing impediments to developing useful predictive models for processes, depositional environments, and lateral and vertical distribution of sand bodies within turbidite systems. To address this concern, we review the principal elements critical to deepwater systems: slump scars, submarine canyons, channels, channel fill deposits, overbank deposits, and lobes and discuss some of their recognition criteria with each different type of data base. Local and regional tectonic setting, relative sea level variations, and bottom current activity are probably the main factors that control size, external geometry, internal stratal configuration, and facies characteristics of both modern and ancient turbidite systems. These factors ultimately control the timing and bounding characteristics between stages of growth of deepwater systems. If comparison of elements from different turbidite deposits using various data types is carried out at similar physical and temporal scales, predictive models eventually may be improved.

A multidisciplinary approach to reservoir subdivision of the Maastrichtian chalk in the Dan field, Danish North Sea

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kristensen, L.; Dons, T.; Schioler, P.

1995-11-01

Correlation of wireline log data from the North Sea chalk reservoirs is frequently hampered by rather subtle log patterns in the chalk section due to the apparent monotonous nature of the chalk sediments, which may lead to ambiguous correlations. This study deals with a correlation technique based on an integration of biostratigraphic data, seismic interpretation, and wireline log correlation; this technique aims at producing a consistent reservoir subdivision that honors both the well data and the seismic data. This multidisciplinary approach has been used to subdivide and correlate the Maastrichtian chalk in the Dan field. The biostratigraphic subdivision is basedmore » on a new detailed dinoflagellate study of core samples from eight wells. Integrating the biostratigraphic results with three-dimensional seismic data allows recognition of four stratigraphic units within the Maastrichtian, bounded by assumed chronostratigraphic horizons. This subdivision is further refined by adding a seismic horizon and four horizons from wireline log correlations, establishing a total of nine reservoir units. The approximate chronostratigraphic nature of these units provides an improved interpretation of the depositional and structural patterns in this area. The three upper reservoir units pinch out and disappear in a northeasterly direction across the field. We interpret this stratal pattern as reflecting a relative sea level fall or regional basinal subsidence during the latest Maastrichtian, possibly combined with local synsedimentary uplift due to salt tectonics. Isochore maps indicate that the underlying six non-wedging units are unaffected by salt tectonics.« less

Hierarchical Marginal Land Assessment for Land Use Planning

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kang, Shujiang; Post, Wilfred M; Wang, Dali

2013-01-01

Marginal land provides an alternative potential for food and bioenergy production in the face of limited land resources; however, effective assessment of marginal lands is not well addressed. Concerns over environmental risks, ecosystem services and sustainability for marginal land have been widely raised. The objective of this study was to develop a hierarchical marginal land assessment framework for land use planning and management. We first identified major land functions linking production, environment, ecosystem services and economics, and then classified land resources into four categories of marginal land using suitability and limitations associated with major management goals, including physically marginal land,more » biologically marginal land, environmental-ecological marginal land, and economically marginal land. We tested this assessment framework in south-western Michigan, USA. Our results indicated that this marginal land assessment framework can be potentially feasible on land use planning for food and bioenergy production, and balancing multiple goals of land use management. We also compared our results with marginal land assessment from the Conservation Reserve Program (CRP) and land capability classes (LCC) that are used in the US. The hierarchical assessment framework has advantages of quantitatively reflecting land functions and multiple concerns. This provides a foundation upon which focused studies can be identified in order to improve the assessment framework by quantifying high-resolution land functions associated with environment and ecosystem services as well as their criteria are needed to improve the assessment framework.« less

Lithosphere structure and subsidence evolution of the conjugate S-African and Argentine margins

NASA Astrophysics Data System (ADS)

Dressel, Ingo; Scheck-Wenderoth, Magdalena; Cacace, Mauro; Götze, Hans-Jürgen; Franke, Dieter

2016-04-01

The bathymetric evolution of the South Atlantic passive continental margins is a matter of debate. Though it is commonly accepted that passive margins experience thermal subsidence as a result of lithospheric cooling as well as load induced subsidence in response to sediment deposition it is disputed if the South Atlantic passive margins were affected by additional processes affecting the subsidence history after continental breakup. We present a subsidence analysis along the SW African margin and offshore Argentina and restore paleobathymetries to assess the subsidence evolution of the margin. These results are discussed with respect to mechanisms behind margin evolution. Therefore, we use available information about the lithosphere-scale present-day structural configuration of these margins as a starting point for the subsidence analysis. A multi 1D backward modelling method is applied to separate individual subsidence components such as the thermal- as well as the load induced subsidence and to restore paleobathymetries for the conjugate margins. The comparison of the restored paleobathymetries shows that the conjugate margins evolve differently: Continuous subsidence is obtained offshore Argentina whereas the subsidence history of the SW African margin is interrupted by phases of uplift. This differing results for both margins correlate also with different structural configurations of the subcrustal mantle. In the light of these results we discuss possible implications for uplift mechanisms.

17 CFR 242.404 - Type, form and use of margin.

Code of Federal Regulations, 2010 CFR

2010-04-01

... (CONTINUED) REGULATIONS M, SHO, ATS, AC, AND NMS AND CUSTOMER MARGIN REQUIREMENTS FOR SECURITY FUTURES Customer Margin Requirements for Security Futures § 242.404 Type, form and use of margin. (a) When margin... (§§ 242.400 through 242.406), provided that: (i) The customer waives any right to redeem the shares...

--No Title--

Science.gov Websites

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30 CFR 204.4 - What is a marginal property under this part?

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 2 2010-07-01 2010-07-01 false What is a marginal property under this part... REVENUE MANAGEMENT ALTERNATIVES FOR MARGINAL PROPERTIES General Provisions § 204.4 What is a marginal property under this part? (a) To qualify as a marginal property eligible for royalty prepayment or...

Comparing vaccines: a systematic review of the use of the non-inferiority margin in vaccine trials.

PubMed

Donken, R; de Melker, H E; Rots, N Y; Berbers, G; Knol, M J

2015-03-17

Non-inferiority (NI) randomized controlled trials (RCTs) aim to demonstrate that a new treatment is no worse than a comparator that has already shown its efficacy over placebo within a pre-specified margin. However, clear guidelines on how the NI margin should be determined are lacking for vaccine trials. A difference (seroprevalence/risk) of 10% or a geometric mean titre/concentration (GMT) ratio of 1.5 or 2.0 in antibody levels is implicitly recommended for vaccine trials. We aimed to explore which NI margins were used in vaccine RCTs and how they were determined. A systematic search for NI vaccine RCTs yielded 177 eligible articles. Data were extracted from these articles using a standardized form and included general characteristics and characteristics specific for NI trials. Relations between the study characteristics and the NI margin used were explored. Among the 143 studies using an NI margin based on difference (n=136 on immunogenicity, n=2 on efficacy and n=5 on safety), 66% used a margin of 10%, 23% used margins lower than 10% (range 1-7.5%) and 11% used margins larger than 10% (range 11.5-25%). Of the 103 studies using a NI margin based on the GMT ratio, 50% used a margin of 0.67/1.5 and 49% used 0.5/2.0. As observed, 85% of the studies did not discuss the method of margin determination; and 19% of the studies lacked a confidence interval or p-value for non-inferiority. Most NI vaccine RCTs used an NI margin of 10% for difference or a GMT ratio of 1.5 or 2.0 without a clear rationale. Most articles presented enough information for the reader to make a judgement about the NI margin used and the conclusions. The reporting on the design, margins used and results of NI vaccine trials could be improved; more explicit guidelines may help to achieve this end. Copyright © 2015 Elsevier Ltd. All rights reserved.

SU-E-T-573: The Robustness of a Combined Margin Recipe for Uncertainties During Radiotherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stroom, J; Vieira, S; Greco, C

2014-06-01

Purpose: To investigate the variability of a safety margin recipe that combines CTV and PTV margins quadratically, with several tumor, treatment, and user related factors. Methods: Margin recipes were calculated by monte-carlo simulations in 5 steps. 1. A spherical tumor with or without isotropic microscopic was irradiated with a 5 field dose plan2. PTV: Geometric uncertainties were introduced using systematic (Sgeo) and random (sgeo) standard deviations. CTV: Microscopic disease distribution was modelled by semi-gaussian (Smicro) with varying number of islets (Ni)3. For a specific uncertainty set (Sgeo, sgeo, Smicro(Ni)), margins were varied until pre-defined decrease in TCP or dose coveragemore » was fulfilled. 4. First, margin recipes were calculated for each of the three uncertainties separately. CTV and PTV recipes were then combined quadratically to yield a final recipe M(Sgeo, sgeo, Smicro(Ni)).5. The final M was verified by simultaneous simulations of the uncertainties.Now, M has been calculated for various changing parameters like margin criteria, penumbra steepness, islet radio-sensitivity, dose conformity, and number of fractions. We subsequently investigated A: whether the combined recipe still holds in all these situations, and B: what the margin variation was in all these cases. Results: We found that the accuracy of the combined margin recipes remains on average within 1mm for all situations, confirming the correctness of the quadratic addition. Depending on the specific parameter, margin factors could change such that margins change over 50%. Especially margin recipes based on TCP-criteria are more sensitive to more parameters than those based on purely geometric Dmin-criteria. Interestingly, measures taken to minimize treatment field sizes (by e.g. optimizing dose conformity) are counteracted by the requirement of larger margins to get the same tumor coverage. Conclusion: Margin recipes combining geometric and microscopic uncertainties quadratically are accurate under varying circumstances. However margins can change up to 50% for different situations.« less

Pembrolizumab Alone or With Idelalisib or Ibrutinib in Treating Patients With Relapsed or Refractory Chronic Lymphocytic Leukemia or Other Low-Grade B-Cell Non-Hodgkin Lymphomas

ClinicalTrials.gov

2017-06-30

Recurrent Chronic Lymphocytic Leukemia; Recurrent Extranodal Marginal Zone Lymphoma of Mucosa-Associated Lymphoid Tissue; Recurrent Grade 1 Follicular Lymphoma; Recurrent Grade 2 Follicular Lymphoma; Recurrent Grade 3 Follicular Lymphoma; Recurrent Lymphoplasmacytic Lymphoma; Recurrent Marginal Zone Lymphoma; Recurrent Nodal Marginal Zone Lymphoma; Recurrent Small Lymphocytic Lymphoma; Recurrent Splenic Marginal Zone Lymphoma; Refractory Chronic Lymphocytic Leukemia; Refractory Extranodal Marginal Zone Lymphoma of Mucosa-Associated Lymphoid Tissue; Refractory Follicular Lymphoma; Refractory Lymphoplasmacytic Lymphoma; Refractory Nodal Marginal Zone Lymphoma; Refractory Small Lymphocytic Lymphoma; Refractory Splenic Marginal Zone Lymphoma; Richter Syndrome; Waldenstrom Macroglobulinemia

Length of positive surgical margin after radical prostatectomy as a predictor of biochemical recurrence.

PubMed

Shikanov, Sergey; Song, Jie; Royce, Cassandra; Al-Ahmadie, Hikmat; Zorn, Kevin; Steinberg, Gary; Zagaja, Gregory; Shalhav, Arieh; Eggener, Scott

2009-07-01

Length and location of positive surgical margins are independent predictors of biochemical recurrence after open radical prostatectomy. We assessed their impact on biochemical recurrence in a large robotic prostatectomy series. Data were collected prospectively from 1,398 men undergoing robotic radical prostatectomy for clinically localized prostate cancer from 2003 to 2008 at a single institution. The associations of preoperative prostate specific antigen, pathological Gleason score, pathological stage and positive surgical margin parameters (location, length and focality) with biochemical recurrence rate were evaluated. Margin status and length were measured by a single uropathologist. Biochemical recurrence was defined as serum prostate specific antigen greater than 0.1 ng/ml on 2 consecutive tests. Cox regression models were constructed to evaluate predictors of biochemical recurrence. Of 1,398 consecutive patients who underwent robotic prostatectomy positive margins were present in 243 (17%) (11% of pathological T2 and 41% of T3). Preoperative prostate specific antigen, pathological stage, Gleason score, margin status, and margin length as a continuous and categorical variable (less than 1, 1 to 3, more than 3 mm) were independent predictors of biochemical recurrence. Patients with negative margins and those with a positive margin less than 1 mm had similar rates of biochemical recurrence (log rank test p = 0.18). Surgical margin location was not independently associated with biochemical recurrence. Margin status and length are independent predictors of biochemical recurrence following robotic radical prostatectomy. Although longer followup and validation studies are necessary for confirmation, patients with a positive margin less than 1 mm appear to have similar recurrence rates as those with negative margins.

The Ills of Marginality: New Perspectives on Health in South Asia.

PubMed

Ecks, Stefan; Sax, William S

2005-12-01

Social marginality and ill health can form an unholy dyad: firstly, groups who suffer from chronic or infectious diseases often find themselves pushed to the margins. Secondly, people who are already on the edge of society tend to suffer more from illness than those at the centre. In development discourse, marginal people are defined as those who are 'not yet' on the same level as the developed mainstream and are in urgent need of aid from the centre. The papers in this special issue take a different approach by insisting that marginality is a radically relational concept: the centre and its margins constitute each other, and the boundaries between them are constantly shifting. The papers show that there are many types of marginality (based on geography, class, caste, sex/gender, ethnicity, etc.), and that each of them has different effects on the health of a particular group. Yet instead of speaking of a plurality of unrelated 'group identities', marginality preserves a sharp sense of unequal power relations between groups. The specific ethnographic contribution to the study of marginality comes from its attention to the point of view of marginal people. This is of critical importance since marginality puts health most under stress when it is clearly and steadily perceived in everyday life. This, in turn, makes it possible to show that living on the margins is not always and everywhere bad for health. While all of the papers present South Asian case studies, the insights and questions are relevant for the study of the ills of marginality in a global perspective.

The Effect of Porcelain Firing and Type of Finish Line on the Marginal Fit of Zirconia Copings

PubMed Central

Vojdani, Mahroo; Safari, Anahita; Mohaghegh, Mina; Pardis, Soheil; Mahdavi, Farideh

2015-01-01

Statement of the Problem Although all-ceramic restorations are broadly used, there is a lack of information concerning how their fit is affected by fabrication procedure and marginal configuration. Purpose The purpose of this study was to evaluate the marginal fit of zirconia CAD/CAM ceramic crowns before and after porcelain firing. The influence of finish line configuration on the marginal fit was also evaluated. Materials and Method Twenty standardized zirconia CAD/CAM copings were fabricated for chamfer and shoulder finish line designs (n=10). The marginal fit of specimens was measured on 18 points, marked on the master metal die by using a digital microscope. After the crowns were finalized by porcelain veneering, the measurements of marginal fit were performed again. The means and standard deviations were calculated and data were analyzed using student’s t-test and paired t-test (α=0.05). Results There were significant differences between marginal fit of chamfer and shoulder finish line groups before and after porcelain firing (p= 0.014 and p= 0.000, respectively). The marginal gap of copings with shoulder finish line was significantly smaller than those with chamfer configuration (p= 0.000), but there were no significant differences between the two marginal designs, after porcelain firing (p= 0.341). Conclusion Porcelain veneering was found to have a statistically significant influence on the marginal fit of zirconia CAD/CAM crowns. Both margin configurations showed marginal gaps that were within a reported clinically acceptable range of marginal discrepancy. PMID:26046107

Effect of two prophylaxis methods on marginal gap of Cl Vresin-modified glass-ionomer restorations.

PubMed

Kimyai, Soodabeh; Pournaghi-Azar, Fatemeh; Daneshpooy, Mehdi; Abed Kahnamoii, Mehdi; Davoodi, Farnaz

2016-01-01

Background. This study evaluated the effect of two prophylaxis techniques on the marginal gap of CI V resin-modified glass-ionomer restorations. Methods. Standard Cl V cavities were prepared on the buccal surfaces of 48 sound bovine mandibular incisors in this in vitro study. After restoration of the cavities with GC Fuji II LC resin-modified glass-ionomer, the samples were randomly assigned to 3 groups of 16. In group 1, the prophylactic procedures were carried out with rubber cup and pumice powder and in group 2 with air-powder polishing device (APD). In group 3 (control), the samples did not undergo any prophylactic procedures. Then the marginal gaps were measured. Two-way ANOVA was used to compare marginal gaps at the occlusal and gingival margins between the groups. Post hoc Tukey test was used for two-by-two comparisons. Statistical significance was set at P < 0.05. Results. There were significant differences in the means of marginal gaps in terms of prophylactic techniques (P < 0.001), with significantly larger marginal gaps in the APD group compared to the pumice and rubber cup group, which in turn exhibited significantly larger marginal gaps compared to the control group (P < 0.0005). In addition, the means of marginal gaps were significant in terms of the margin type (P < 0.001), with significantly larger gaps at gingival margins compared to the occlusal margins (P < 0.0005). Conclusion. The prophylactic techniques used in this study had a negative effect on the marginal gaps of Cl V resin-modified glass-ionomer restorations.

Marginal Lands: Concept, Assessment and Management

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kang, Shujiang; Post, Wilfred M; West, Tristram O.

2013-01-01

Marginal lands have received wide attention for their potential to improve food security and support bioenergy production. However, environmental, ecosystem service, and sustainability concerns have been widely raised over the use of marginal land. Knowledge of the extent, location, and quality of marginal lands as well as their assessment and management are limited and diverse. This paper provides a review of the historical development of marginal concept, its application and assessment. Limitations and priority research needs of marginal land assessment and management were discussed.

Invasive vulvar carcinoma and the question of the surgical margin.

PubMed

Palaia, Innocenza; Bellati, Filippo; Calcagno, Marco; Musella, Angela; Perniola, Giorgia; Panici, Pierluigi B

2011-08-01

To assess the discrepancy between width of surgical margin measured with the naked eye/ruler by a surgeon before removing an invasive vulvar carcinoma, and width of margin measured under microscope by pathologist after fixation of the resected lesion with formalin. Potential relationships between discrepancy and disease recurrence were also investigated. This prospective study was conducted with resected lesions from 86 women who underwent surgery for primary/recurrent invasive vulvar carcinoma. After the surgeon removed the lesions surrounded by 1-2-cm margins, the pathologist determined margin width at the 4 cardinal points of 86 lesions (for a total of 344 margin assessments), first macroscopically and then under the microscope. A safety margin of 0.8 cm on microscopic view was achieved in 83% of cases (112 of 135) when the macroscopic measurement was 1cm, in 91% of cases (58 of 64) when it was 1.5 cm, and 98% of cases (105 of 107) when it was 2 cm. There was a small discrepancy between the surgeon's intent and the microscopic margin measurement, mostly related to tissue shrinkage. A 1-cm surgical margin corresponded to a 0.8-cm margin in microscopic view (the "safe margin") in most cases. Copyright © 2011 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.

Chapter 34: Geology and petroleum potential of the rifted margins of the Canada Basin

USGS Publications Warehouse

Houseknecht, D.W.; Bird, K.J.

2011-01-01

Three sides of the Canada Basin are bordered by high-standing, conjugate rift shoulders of the Chukchi Borderland, Alaska and Canada. The Alaska and Canada margins are mantled with thick, growth-faulted sediment prisms, and the Chukchi Borderland contains only a thin veneer of sediment. The rift-margin strata of Alaska and Canada reflect the tectonics and sediment dispersal systems of adjacent continental regions whereas the Chukchi Borderland was tectonically isolated from these sediment dispersal systems. Along the eastern Alaska-southern Canada margin, termed herein the 'Canning-Mackenzie deformed margin', the rifted margin is deformed by ongoing Brooks Range tectonism. Additional contractional structures occur in a gravity fold belt that may be present along the entire Alaska and Canada margins of the Canada Basin. Source-rock data inboard of the rift shoulders and regional palaeogeographic reconstructions suggest three potential source-rock intervals: Lower Cretaceous (Hauterivian-Albian), Upper Cretaceous (mostly Turonian) and Lower Palaeogene. Burial history modelling indicates favourable timing for generation from all three intervals beneath the Alaska and Canada passive margins, and an active petroleum system has been documented in the Canning-Mackenzie deformed margin. Assessment of undiscovered petroleum resources indicates the greatest potential in the Canning-Mackenzie deformed margin and significant potential in the Canada and Alaska passive margins. ?? 2011 The Geological Society of London.

Marginal Teachers from the Eyes of School Principals: Concept, Problems and Management Strategies

ERIC Educational Resources Information Center

Erdogan, Cetin; Demirkasimoglu, Nihan

2016-01-01

This research aimed to determine how Turkish principals define marginal teachers and which strategies they use to deal with them. Within this purpose, the following points are examined: (a) the concept of marginal teacher, (b) the underlying reasons for marginal teacher behaviors, (c) the problems marginal teachers cause in school settings, (d)…

NRC Continental Margins Workshop

NASA Astrophysics Data System (ADS)

Katsouros, Mary Hope

The Ocean Studies Board of the National Research Council is organizing a workshop, “Continental Margins: Evolution of Passive Continental Margins and Active Marginal Processes,” to stimulate discussion and longterm planning in the scientific community about the evolution of all types of continental margins. We want to coordinate academic, industry, and government agency efforts in this field, and to enhance communication between sea-based and land-based research programs.The continental margins constitute the only available record of the long-term dynamic interaction of oceanic and continental lithosphere. Of great interest are the unique structures and thick sedimentary sequences associated with this interaction. A major focus of the workshop will be to define strategies for exploring and understanding the continental margins in three dimensions and through geologic time. The workshop will be divided into 7 working groups, each concentrating on a major issue in continental margins research. A background document is being prepared summarizing recent research in specific continental margin fields and identifying key scientific and technical issues.

Open architecture design and approach for the Integrated Sensor Architecture (ISA)

NASA Astrophysics Data System (ADS)

Moulton, Christine L.; Krzywicki, Alan T.; Hepp, Jared J.; Harrell, John; Kogut, Michael

2015-05-01

Integrated Sensor Architecture (ISA) is designed in response to stovepiped integration approaches. The design, based on the principles of Service Oriented Architectures (SOA) and Open Architectures, addresses the problem of integration, and is not designed for specific sensors or systems. The use of SOA and Open Architecture approaches has led to a flexible, extensible architecture. Using these approaches, and supported with common data formats, open protocol specifications, and Department of Defense Architecture Framework (DoDAF) system architecture documents, an integration-focused architecture has been developed. ISA can help move the Department of Defense (DoD) from costly stovepipe solutions to a more cost-effective plug-and-play design to support interoperability.

The Variability in Surgical Margin Reporting in Limb Salvage Surgery for Sarcoma

PubMed Central

Hoang, Kevin; Gao, Yubo; Miller, Benjamin J.

2015-01-01

Background Surgical margins are a standard reported measurement in tumor surgery that has implications for functional outcome, local control, and overall survival. There is no single accepted classification, and it is unclear what form or margin reporting predominates in the sarcoma literature. Methods We performed a PubMed literature search to identify articles that reported surgical margins and oncologic outcomes in limb salvage surgery for sarcoma from 1980 to 2013. We recorded the margin classification, specialty of the journal, specialty of the author, and location of the authors' institution. Results We found that 159/448 (35%) of articles included in the study did not report surgical margins. Of the 289 papers that did include data on margins, 160 (55%) of articles used Enneking's classification. There has been an increase over time in the proportion of articles reporting surgical margins by the residual tumor (R) classification and the proportion of articles reporting margins dichotomously as “positive” or “negative.” Conclusions We did not find a common method for reporting margins in the limb salvage sarcoma literature. Of most concern was over 1/3 of clinical reports of oncologic outcomes did not include margin status, which substantially compromises any conclusions that readers may infer about treatment success, local recurrence, or survival. We believe there should be renewed efforts to encourage use of a common surgical margin reporting system that is simple, reproducible, and prognostic. PMID:26361463

Comparative biogeochemistry-ecosystem-human interactions on dynamic continental margins

USGS Publications Warehouse

Levin, Lisa A.; Liu, Kon-Kee; Emeis, Kay-Christian; Breitburg, Denise L.; Cloern, James; Deutsch, Curtis; Giani, Michele; Goffart, Anne; Hofmann, Eileen E.; Lachkar, Zouhair; Limburg, Karin; Liu, Su-Mei; Montes, Enrique; Naqvi, Wajih; Ragueneau, Olivier; Rabouille, Christophe; Sarkar, Santosh Kumar; Swaney, Dennis P.; Wassman, Paul; Wishner, Karen F.

2014-01-01

The ocean’s continental margins face strong and rapid change, forced by a combination of direct human activity, anthropogenic CO2-induced climate change, and natural variability. Stimulated by discussions in Goa, India at the IMBER IMBIZO III, we (1) provide an overview of the drivers of biogeochemical variation and change on margins, (2) compare temporal trends in hydrographic and biogeochemical data across different margins (3) review ecosystem responses to these changes, (4) highlight the importance of margin time series for detecting and attributing change and (5) examine societal responses to changing margin biogeochemistry and ecosystems. We synthesize information over a wide range of margin settings in order to identify the commonalities and distinctions among continental margin ecosystems. Key drivers of biogeochemical variation include long-term climate cycles, CO2-induced warming, acidification, and deoxygenation, as well as sea level rise, eutrophication, hydrologic and water cycle alteration, changing land use, fishing, and species invasion. Ecosystem responses are complex and impact major margin services including primary production, fisheries production, nutrient cycling, shoreline protection, chemical buffering, and biodiversity. Despite regional differences, the societal consequences of these changes are unarguably large and mandate coherent actions to reduce, mitigate and adapt to multiple stressors on continental margins.

Pegfilgrastim and Rituximab in Treating Patients With Untreated, Relapsed, or Refractory Follicular Lymphoma, Small Lymphocytic Lymphoma, or Marginal Zone Lymphoma

ClinicalTrials.gov

2017-09-08

Contiguous Stage II Grade 1 Follicular Lymphoma; Contiguous Stage II Grade 2 Follicular Lymphoma; Contiguous Stage II Grade 3 Follicular Lymphoma; Contiguous Stage II Marginal Zone Lymphoma; Contiguous Stage II Small Lymphocytic Lymphoma; Extranodal Marginal Zone B-cell Lymphoma of Mucosa-associated Lymphoid Tissue; Nodal Marginal Zone B-cell Lymphoma; Noncontiguous Stage II Grade 1 Follicular Lymphoma; Noncontiguous Stage II Grade 2 Follicular Lymphoma; Noncontiguous Stage II Grade 3 Follicular Lymphoma; Noncontiguous Stage II Marginal Zone Lymphoma; Noncontiguous Stage II Small Lymphocytic Lymphoma; Recurrent Grade 1 Follicular Lymphoma; Recurrent Grade 2 Follicular Lymphoma; Recurrent Grade 3 Follicular Lymphoma; Recurrent Marginal Zone Lymphoma; Recurrent Small Lymphocytic Lymphoma; Splenic Marginal Zone Lymphoma; Stage I Grade 1 Follicular Lymphoma; Stage I Grade 2 Follicular Lymphoma; Stage I Grade 3 Follicular Lymphoma; Stage I Marginal Zone Lymphoma; Stage I Small Lymphocytic Lymphoma; Stage III Grade 1 Follicular Lymphoma; Stage III Grade 2 Follicular Lymphoma; Stage III Grade 3 Follicular Lymphoma; Stage III Marginal Zone Lymphoma; Stage III Small Lymphocytic Lymphoma; Stage IV Grade 1 Follicular Lymphoma; Stage IV Grade 2 Follicular Lymphoma; Stage IV Grade 3 Follicular Lymphoma; Stage IV Marginal Zone Lymphoma; Stage IV Small Lymphocytic Lymphoma