Major structural controls on the distribution of pre-Tertiary rocks, Nevada Test Site vicinity, southern Nevada

USGS Publications Warehouse

Cole, James C.

1997-01-01

The lateral and vertical distributions of Proterozoic and Paleozoic sedimentary rocks in southern Nevada are the combined products of original stratigraphic relationships and post-depositional faults and folds. This map compilation shows the distribution of these pre-Tertiary rocks in the region including and surrounding the Nevada Test Site. It is based on considerable new evidence from detailed geologic mapping, biostratigraphic control, sedimentological analysis, and a review of regional map relationships.Proterozoic and Paleozoic rocks of the region record paleogeographic transitions between continental shelf depositional environments on the east and deeper-water slopefacies depositional environments on the west. Middle Devonian and Mississippian sequences, in particular, show strong lateral facies variations caused by contemporaneous changes in the western margin of North America during the Antler orogeny. Sections of rock that were originally deposited in widely separated facies localities presently lie in close proximity. These spatial relationships chiefly result from major east- and southeastdirected thrusts that deformed the region in Permian or later time.Somewhat younger contractional structures are identified within two irregular zones that traverse the region. These folds and thrusts typically verge toward the west and northwest and overprint the relatively simple pattern of the older contractional terranes. Local structural complications are significant near these younger structures due to the opposing vergence and due to irregularities in the previously folded and faulted crustal section.Structural and stratigraphic discontinuities are identified on opposing sides of two north-trending fault zones in the central part of the compilation region north of Yucca Flat. The origin and significance of these zones are enigmatic because they are largely covered by Tertiary and younger deposits. These faults most likely result from significant lateral offset, most likely in the sinistral sense.Low-angle normal faults that are at least older than Oligocene, and may pre-date Late Cretaceous time, are also present in the region. These faults are shown to locally displace blocks of pre-Tertiary rock by several kilometers. However, none of these structures can be traced for significant distances beyond its outcrop extent, and the inference is made that they do not exert regional influence on the distribution of pre-Tertiary rocks. The extensional strain accommodated by these low-angle normal faults appears to be local and highly irregular.

The Dauki Fault and its Shillong-Sylhet Thrust Anticline-Foredeep Pair: A Footwall Reactivation along the Progressive Burma-India Collision

NASA Astrophysics Data System (ADS)

Seeber, L.; Ferguson, E. K.; Grall, C.; Steckler, M. S.; Betka, P. M.; Akhter, S. H.

2016-12-01

The Shillong Massif and the Sylhet basin form a south-verging anticline-foredeep pair associated with the E-W striking Dauki fault. Fold geometry and receiver-functions identify it as a blind thrust fault dipping north into the craton. This contractional structure may represent an incipient forward jump of the Himalayan front to the trailing margin of India. The Shillong Massif is one of the largest known basement-cored anticlines and is delineated by a relict erosional surface and folded strata. Where best exposed in the central segment, it has a steep southern limb and a gentle northern limb. This asymmetry is mirrored in the Sylhet foredeep, with a steep north flank and low dip south flank. The combined structure has 5 km of relief, most of which developed during the Quaternary. This foredeep overprints a thicker sequence that records the progradation of the Brahmaputra delta. These older strata thicken southward as expected at a passive margin. The Sylhet Traps, which are coeval with India-Antarctica rifting, outcrop along the southern limb of the anticline. Associated basalt dikes are also parallel to the E-W Dauki structure. The basal Cretaceous-Paleogene shallow marine strata onlap northward the regional unconformity above the cratonic and trap rocks. This suggests that the Dauki thrust front traces an E-W segment of the passive margin and former rift. The IndoBurma forearc overrides the Dauki structure 200 km farther west on the foredeep (south) side than on the massif (north) side of the Dauki fault. Much of this differential advance of the Burma deformation front predates the Dauki foredeep and was a response to the shape of the passive margin of India. This deformation front, known locally as the Haflong Fault, crosses obliquely the Dauki thrust front. Evidence includes contractional structures verging up-dip onto the forelimb of the Shillong anticline. The Shillong Massif-Sylhet Foredeep pair has a strong gravity signature that can be traced eastward across most of the IndoBurma Ranges. Correlated topography and drainage features, including the Imphal intramountain basin, and a drainage switch from northward to southward across this basin suggest that this entire gravity anomaly reflects differential uplift along the eastward continuation of the buried Dauki fault and not just a buried passive margin.

Tectono-stratigraphy and low-grade metamorphism of Late Permian and Early Jurassic accretionary complexes within the Kurosegawa belt, Southwest Japan: Implications for mechanisms of crustal displacement within active continental margin

NASA Astrophysics Data System (ADS)

Hara, Hidetoshi; Kurihara, Toshiyuki; Mori, Hiroshi

2013-04-01

We characterize the tectono-stratigraphic architecture and low-grade metamorphism of the accretionary complex preserved in the Kurosegawa belt of the Kitagawa district in eastern Shikoku, Southwest Japan, in order to understand its internal structure, tectono-metamorphic evolution, and assessments of displacement of continental fragments within the complex. We report the first ever documented occurrence of an Early Jurassic radiolarian assemblage within the accretionary complex of the Kurosegawa belt that has been previously classified as the Late Permian accretionary complex, thus providing a revised age interpretation for these rocks. The accretionary complex is subdivided into four distinct tectono-stratigraphic units: Late Permian mélange and phyllite units, and Early Jurassic mélange and sandstone units. The stratigraphy of these four units is structurally repeated due to an E-W striking, steeply dipping regional fault. We characterized low-grade metamorphism of the accretionary complex via illite crystallinity and Raman spectroscopy of carbonaceous material. The estimated pattern of low-grade metamorphism showed pronounced variability within the complex and revealed no discernible spatial trends. The primary thermal structure in these rocks was overprinted by later tectonic events. Based on geological and thermal structure, we conclude that continental fragments within the Kurosegawa belt were structurally translated into both the Late Permian and Early Jurassic accretionary complexes, which comprise a highly deformed zone affected by strike-slip tectonics during the Early Cretaceous. Different models have been proposed to explain the initial structural evolution of the Kurosegawa belt (i.e., micro-continent collision and klippe tectonic models). Even if we presuppose either model, the available geological evidence requires a new interpretation, whereby primary geological structures are overprinted and reconfigured by later tectonic events.

Constraints on the depositional age and tectonometamorphic evolution of marbles from the Biharia Nappe System (Apuseni Mountains, Romania)

NASA Astrophysics Data System (ADS)

Reiser, Martin Kaspar; Schuster, Ralf; Tropper, Peter; Fügenschuh, Bernhard

2017-04-01

Basement rocks from the Biharia Nappe System in the Apuseni Mountains comprise several dolomite and calcite marble sequences or lenses which experienced deformation and metamorphic overprint during the Alpine orogeny. New Sr, O and C-isotope data in combination with considerations from the lithological sequences indicate Middle to Late Triassic deposition of calcite marbles from the Vulturese-Belioara Series (Biharia Nappe s.str.). Ductile deformation and large-scale folding of the siliciclastic and carbonatic lithologies is attributed to NW-directed nappe stacking during late Early Cretaceous times (D2). The studied marble sequences experienced a metamorphic overprint under lower greenschist- facies conditions (316-370 °C based on calcite - dolomite geothermometry) during this tectonic event. Other marble sequences from the Biharia Nappe System (i.e. Vidolm and Baia de Arieș nappes) show similarities in the stratigraphic sequence and their isotope signature, together with a comparable structural position close to nappe contact. However, the dataset is not concise enough to allow for a definitive attribution of a Mesozoic origin to other marble sequences than the Vulturese-Belioara Series.

Late-stage sinking of plutons

USGS Publications Warehouse

Glazner, A.F.; Miller, D.M.

1997-01-01

Many granodiorite to diorite plutons in the Great Basin of western North America are surrounded by rim monoclines or anticlines that suggest relative downward movement of the plutons while wall rocks were hot and ductile. We propose that such plutons rise to a level of approximately neutral buoyancy and then founder as their densities increase ??? 40% during crystallization. Late-stage sinking of intermediate to mafic plutons should be common when wall rocks are rich in weak, low-density minerals such as quartz and calcite. Structures related to sinking will overprint those related to initial pluton emplacement and may be mistaken for regional tectonic structures.

Post-Metamorphic Thermal Anomaly across the Nacimiento Block, Central California: a Hydrothermal Overprint?

NASA Astrophysics Data System (ADS)

Lacroix, B.; Hughes, J.; Lahfid, A.; Delchini, S.

2017-12-01

The thermal history of the Nacimiento block located within the Franciscan Complex (California, USA) has been previously proposed based on both vitrinite reflectance (Rm) and illite cristallinity methods (Underwood et al., 1995). These authors suggest that the Nacimiento block is locally perturbed by a thermal anomaly (up to 300ºC), probably caused by post-metamorphic hydrothermal activity linked to the emplacement of an Au-deposit: the Los Burros Gold deposit. Although both thermal anomaly and deposit seem spatially correlated, their relationship is still poorly constrained. Detailed geological and structural mapping within the Los Burros Mining District (LBMD) coupled with a thermal study was conducted to better understand processes responsible for the anomalous temperatures recorded near the deposit. The regional maximum temperature reached by metasediments from the Nacimiento block have been first investigated using the Raman Spectroscopy of Carbonaceous Materials (RSCM) method. In addition, through careful fluid-inclusion and stable isotopes (O and C) studies on the deposit, the temperature and the potential source of the fluid responsible for the Los Burros Au-deposit emplacement were investigated. RSCM technique confirms the presence of a thermal anomaly in the range 260-320ºC near LBMD. However, our structural and petrographic results suggest that the thermal anomaly is not correlated to a post-metamorphic hydrothermal overprint but rather to a late, transpressive deformation uplifting buried metamorphic rocks.

Superposed buckle folding in the eastern Iberian Chain, Spain

NASA Astrophysics Data System (ADS)

Simón, José L.

2004-08-01

The Aliaga area (eastern Iberian Chain) shows large-scale examples of buckle superposition developed during Tertiary folding. In most cases, ENE-trending folds overprint earlier NNW-SSE-trending ones. The resulting structures are mapped, analysed, and genetically classified by comparison with analogue models described by several authors. The following types are found: standard Type 1 (1a: dome-and-basin structure, 1b: unequal-wavelength overprinted folds); modified Type 1 (1c: T-shaped 'joined' folds; 1d: T-shaped 'abutting' folds; 1e: L-shaped folds; 1f: 'snake-like' folds); standard Type 2 (2a: non-cylindrical buckling of earlier axial surfaces involving hinge replacement). Different superposed sets of flexural-slip striations record successive folding episodes in snake-like folds, and hinge replacement in the case of Type 2a superpositions. Types 1 and 2 apparently develop where the earlier folds have interlimb angles over and below 90°, respectively, which fits the results of analogue modelling and theoretical analysis by previous authors. Types 1b and 1d are associated with higher W1/W2 wavelength ratios than Types 1a and 1c. Other controlling factors are viscosity contrast and erosion processes. Specifically, erosion of competent limestone beds in the hinge zone of a NNW-SSE-trending anticline allowed the near-vertical eastern limb to be refolded into snake-like folds.

Dating the Duration and Termination of Sinistral Shear in the Western Tauern Window: Implications for Indentation and Exhumation in the Eastern Alps

NASA Astrophysics Data System (ADS)

Schneider, Susanne; Hammerschmidt, Konrad; Rosenberg, Claudio Luca

2010-05-01

The internal structure of the Tauern Window (TW) consists of parallel sets of upright antiforms, striking ENE in the west and ESE in the east. The long axes of the upright folds are parallel to shear zones (SZ), which are generally sinistral in the west and dextral in the east. The formation of these structures has been interpreted as the result of a coeval, conjugate system, forming in response to south-Alpine indentation (Rosenberg et al., 2004), or as a change in the regional shortening direction through time (Polinski and Eisbacher, 1992; Neubauer et al., 2000; Mancktelow et al., 2001). The latter models suggested an Oligocene age for sinistral displacements, followed by Miocene dextral ones. Therefore, determining the timing of these different shear zones is a key to understand the tectonic significance of the structures described above. We analysed the kinematics and determined the formation age of the mylonitic foliation of two sinistral shear zones in the western TW (Ahorn SZ, Olperer SZ). In addition to left lateral displacements, kinematic indicators in the YZ plane for both shear zones point to differential vertical displacements, namely S-side up. We performed absolute age determinations of deformation by dating syn- and on post-kinematically grown minerals, the latter overprinting the former ones microstructurally on the microscopic scale. For this purpose we selected syn-kinematic phengites of mylonites and ultra-mylonites from shear bands, strain caps and also from overprinting statically grown phengites overprinting the mylonitic foliation. The Ar/Ar In-situ UV-laser ablation method was applied using a noble gas mass spectrometer. For comparison micas of an undeformed host rock were also dated using the same method. The obtained age values of syn-kinematic phengites vary between 12-24 Ma. This age variation is commonly found within single grains. Postkinematic, phengites overgrowing the syn-kinematic grains yield the youngest age values, namely 5-12 Ma. We observe a systematic relationship between the ages of the postkinematic grains and the age spread of the syn-kinematic ones. The age of the post-kinematic grains always coincides with the youngest age determined within the syn-kinematic grains. We interpret this relationship as indicating that the growth of post-kinematic minerals followed almost instantaneously the termination of deformation. As a consequence, the age of phengites overprinting the mylonitic foliation yields a precise age for the termination of deformation. The spread in age variation of phengites goes together with a spread in Si content, consequently the postkinematic phengites have a higher Si content compared to the overprinted syn-kinematic ones. Therefore the metamorphic pressure conditions of the post-kinematic phengites were lower, indicating continuous deformation during exhumation within a time interval of approximately 12 Ma. We interpret these ages as formation ages during or after shearing, respectively. Muscovite blasts of the undeformed sample yield age values varying between 22 and 34 Ma. We interpret these ages as cooling ages, following the metamorphic peak temperatures. To conclude, sinistral shear in the western TW started at least 24 Ma ago and terminated at 12 Ma. Therefore, these shear zones do not predate dextral displacements or lateral extrusion within the eastern Tauern sub-dome, which are also Miocene (Inger & Cliff, 1994, Frisch et al., 1998, Glodny et al., 2008). This conclusion suggests that they formed as part of an orogen-scale conjugate system, accommodating Miocene shortening due to South-Alpine indentation. Since these shear zones are transpressive, showing a component of vertical displacement, their age may also constrain exhumation of the Tauern dome.

From Permo-Triassic lithospheric thinning to Jurassic rifting at the Adriatic margin: Petrological and geochronological record in Valtournenche (Western Italian Alps)

NASA Astrophysics Data System (ADS)

Manzotti, Paola; Rubatto, Daniela; Darling, James; Zucali, Michele; Cenki-Tok, Bénédicte; Engi, Martin

2012-08-01

Slices of polycyclic metasediments (marbles and meta-cherts) are tectonically amalgamated with the polydeformed basement of the Dent Blanche tectonic system along a major Alpine shear zone in the Western Alps (Becca di Salé area, Valtournenche Valley). A combination of techniques (structural analysis at various scales, metamorphic petrology, geochronology and trace element geochemistry) was applied to determine the age and composition of accessory phases (titanite, allanite and zircon) and their relation to major minerals. The results are used to reconstruct the polyphase structural and metamorphic histories, comprising both pre-Alpine and Alpine cycles. The pre-Alpine evolution is associated with low-pressure high-temperature metamorphism related to Permo-Triassic lithospheric thinning. In meta-cherts, microtextural relations indicate coeval growth of allanite and garnet during this stage, at ~ 300 Ma. Textures of zircon also indicate crystallisation at HT conditions; ages scatter from 263 to 294 Ma, with a major cluster of data at ~ 276 Ma. In impure marble, U-Pb analyses of titanite domains (with variable Al and F contents) yield apparent 206Pb/238U dates range from Permian to Jurassic. Chemical and isotopic data suggest that titanite formed at Permian times and was then affected by (extension-related?) fluid circulation during the Triassic and Jurassic, which redistributed major elements (Al and F) and partially opened the U-Pb system. The Alpine cycle lead to early blueschist facies assemblages, which were partly overprinted under greenschist facies conditions. The strong Alpine compressional overprint disrupted the pre-Alpine structural imprint and/or reactivated earlier structures. The pre-Alpine metamorphic record, preserved in these slices of metasediments, reflects the onset of the Permo-Triassic lithospheric extension to Jurassic rifting.

Blueschists and eclogites from southern Sifnos (Cyclades, Greece)

NASA Astrophysics Data System (ADS)

Weil, Jonas; Petrakakis, Konstantin; Grasemann, Bernhard; Iglseder, Christoph

2010-05-01

Eclogite/blueschist facies rocks from northern Sifnos (Cyclades) are well known and have been described by many authors. A small occurrence of similar rocks in the south-west of Sifnos has been investigated and is compared to other occurrences in terms of their mineral assemblages, chemistry, petrography and structural position. The tectono-metamorphic evolution on Sifnos is characterized by a regional blueschist / eclogite facies metamorphism (M1) during the Eocene, followed by a regional Oligo-Miocene medium pressure overprint (M2). The investigated rocks from the Fikiada Bay area formed during M1 but were overprinted by a brittle / ductile M2 event. The high-pressure rock assemblage of Fikiada bay represents a sequence of metabasites, metaacidites, and metasediments with a foliation-parallel compositional layering. Rootless isoclinal folding of the regional foliation is common with fold axes trending roughly NW-SE; hinges are overprinted by later axial foliation planes. The foliation is well developed and mostly dips to N to E, the main pervasive stretching lineation is shallow and plunging to NE. Grt- rich dark blueschists, bearing eclogite-boudins of some dm size, alternate with lighter Qtz-rich Grt-bearing, cm to m thick layers. Massive, very coarse grained Ep+Chl+Ab -rich gneisses form layers with up to 3 m thickness. Metasediments comprise light Cal-rich gneisses as well as metapelites and quartzites. These lithologies are overlain by highly strained calcite marbles bearing boudins of Dol-marble. Foliation, stretching lineation and isoclinal folds show the same orientation as in the silicates. The blueschists show the characteristic assemblage Gln + Grt + Ep + Ab + Phg + Pg +Qtz (+Cal) + Mag. Inclusions in large poikiloblastic Grt reveal an earlier compositional layering: Domains with conserved foam microstructures of Qtz and domains of massive Grt including relics of Jd (XNa = 0.9), Ctd, Ep, Rt and Mag. Gln shows a zonal pattern with Mg-rich cores to ferro-glaucophane and crossite- richer rims. Ep is zoned too with decreasing Fe from core to rim, while Grt-poikiloblasts are nearly homogeneous in composition. Eclogitic assemblages consist of Grt + Omp + Ep + Phg + Gln ± Qtz. A greenschist-facies overprint accompanied by Fe- and CO2- rich fluids is mostly evident along shear bands of variable thickness from thin section to outcrop scale. It is best documented by the growth of syntectonic Ab+Chl neoblasts. Metabasite layers intercalated with the marble show a pervasive greenschist-facies overprint with extensive, neoblastic growth of Chl an Ab. Early Ep remains unaffected, but Gln and Grt are preserved only as relics. Petrography and mineral chemistry of southern Sifnos HP-rocks comply with the occurrence in northern Sifnos (e.g. comprehensive description by Schliestedt 1986) References: Schliestedt, M., 1986. Eclogite-blueschist relationships as evidenced by mineral equilibria in the high-pressure rocks of Sifnos (Cycladic islands), Greece. Journal of Petrology, 27,1437-1459 Mineral abbreviations after Kretz, 1983: Symbols for rock-forming minerals. American Mineralogist, 68, 277-279

Anatomy of a Plate Boundary at Shallow Crustal Levels: a Composite Section from the Alpine Fault, New Zealand

NASA Astrophysics Data System (ADS)

Barth, N. C.; Toy, V. G.; Boulton, C. J.; Carpenter, B. M.

2010-12-01

New Zealand's Alpine Fault is mostly a moderately SE-dipping dextral reverse plate boundary structure, but at its southern end, strike-slip-normal motion is indicated by offset of recent surfaces, juxtaposition of sediments, and both brittle and ductile shear sense indicators. At the location of uplift polarity reversal fault rocks exhumed from both the hangingwall Pacific and footwall Australian Plates are juxtaposed, offering a remarkably complete cross section of the plate boundary at shallow crustal levels. We describe Alpine Fault damage zone and fault core structures overprinted on Pacific and Australian plate mylonites of a variety of compositions, in a fault-strike perpendicular composite section spanning the reversal in dip-slip polarity. The damage zone is asymmetric; on the Australian Plate 160m of quartzose paragneiss-derived mylonites are overprinted by brittle faults and fractures that increase in density towards the principal slip surface (PSS). This damage zone fabric consists of 1-10m-spaced, moderately to steeply-dipping, 1-20cm-thick gouge-filled faults, overprinted on and sub-parallel to a mylonitic foliation sub-parallel to the PSS. On the Pacific Plate, only 40m of the 330m section of volcaniclastic-derived mylonites have brittle damage in the form of unhealed fractures and faults, as well as a pervasive greenschist facies hydrothermal alteration absent in the footwall. These damage-related structures comprise a network of small-offset faults and fractures with increasing density and intensity towards the PSS. The active Pacific Plate fault core is composed of ~1m of cataclasite grading into folded protocataclasite that is less folded and fractured with increasing distance from the PSS. The active Australian Plate fault core is <1.5m wide and consists of 3 distinct foliated clay gouges, as well as a 4cm thick brittle ultracataclasite immediately adjacent to the active PSS. The Australian Plate foliated clay gouge contains stringers of quartz that become less continuous and more sigmoidal toward the PSS, indicating a strain gradient across the gouge zone. Gouge textures are consistent with deformation by pressure solution. Intact wafers from one of the gouges, experimentally -sheared in a biaxial configuration under true-triaxial loading at σn’= 31MPa and Pf = 10MPa, yielded a friction coefficient, μss = 0.32 and displayed velocity strengthening behavior. No significant re-strengthening was observed during hold periods of slide-hold tests. Well-cemented glacial till (~8000 years old), which caps many outcrops, is a marker that shows that the damage zone is not active in the near-surface, but most of the fault core is. The active near-surface damage zone here is <40m wide and the active fault core is <2.5m wide. Both overprint a much wider, inactive damage zone. The combination of rheologically-weak Australian Plate fault rocks with surface rupture traces indicates distinctly different coseismic and interseismic behaviors along the southern strike-slip-normal segment of the Alpine Fault.

The lateral boundary of a metamorphic core complex: The Moutsounas shear zone on Naxos, Cyclades, Greece☆

PubMed Central

Cao, Shuyun; Neubauer, Franz; Bernroider, Manfred; Liu, Junlai

2013-01-01

We describe the structure, microstructures, texture and paleopiezometry of quartz-rich phyllites and marbles along N-trending Moutsounas shear zone at the eastern margin of the Naxos metamorphic core complex (MCC). Fabrics consistently indicate a top-to-the-NNE non-coaxial shear and formed during the main stage of updoming and exhumation between ca. 14 and 11 Ma of the Naxos MCC. The main stage of exhumation postdates the deposition of overlying Miocene sedimentary successions and predates the overlying Upper Miocene/Pliocene conglomerates. Detailed microstructural and textural analysis reveals that the movement along the Moutsounas shear zone is associated with a retrograde greenschist to subgreenschist facies overprint of the early higher-temperature rocks. Paleopiezometry on recrystallized quartz and calcite yields differential stresses of 20–77 MPa and a strain rate of 10−15–10−13 s−1 at 350 °C for quartz and ca. 300 °C for calcite. Chlorite geothermometry of the shear zone yields two temperature regimes, 300–360 °C, and 200–250 °C. The lower temperature group is interpreted to result from late-stage hydrothermal overprint. PMID:26523079

Paleomagnetic Progress in Peri-Gondwanan Terranes of Cape Breton Island, Nova Scotia

NASA Astrophysics Data System (ADS)

Grunow, A. M.; Thompson, M. D.; Barr, S. M.; White, C. E.

2009-05-01

Paleopoles from primary Ediacaran magnetization directions established the Gondwanan origin of northern Appalachian Avalonian terranes, but magnetic overprints in the same rocks also provide useful tectonic information. Thus, in the Southeastern New England Avalon Zone, virtual geomagnetic poles (VGPs) calculated from magnetic B and C components in both 595 Ma Lynn-Mattapan volcanic rocks and 490-488 Ma Nahant Gabbro track mid- and late Paleozoic segments of the North American apparent polar wander path (APWP), suggesting the influence of Acadian and Neo-Acadian accretionary events. We report here on multi- vectorial magnetizations in pilot samples from Cape Breton Island, Nova Scotia where the Bras d'Or and Mira terranes represent both Ganderian and Avalonian elements transferred from Gondwana. Overprint relationships in these terranes may constrain their amalgamation with each other as well their docking with Laurentia. As in southeastern New England, secondary remanences can be identified in Cape Breton Island as consistent magnetization directions in rocks of differing ages. The S- to SSE-trending and gently downward pointing direction reported in 1985 by Johnson and Van der Voo in Middle Cambrian sedimentary rocks of the Bourinot Group (Bras d'Or terrane), for example, is also present in the 563 Ma Main à Dieu Formation and in 620 Ma Chisholm Brook Granite and East Bay Hill rhyolite (Mira terrane). This magnetization represents the C component already found around Boston, MA. The resulting VGPs in both areas occupy positions on the North American APWP consistent with a Neo-Acadian overprint, possibly related to the docking of the Meguma terrane against previously accreted Avalonia. Other overprint directions encountered in this investigation give rise to VGPs that do not coincide with the North American APWP, hence appear to reflect tectonic events independent of Laurentia. One such cluster comprising both Mira and Bras d'Or VGPs includes the paleopole also reported by Johnson and Van der Voo for volcanic rocks in the Bourinot Group. This relationship suggests that the two terranes were neighbors at moderate southerly paleolatitudes by ca. 505 Ma and allows the possibility that Bourinot volcanism played a role in overprinting older rocks including 620 Ma East Bay Hills rhyolite (Mira) and 553 Ma Creignish Hills granite (Bras d'Or). Another intriguing observation from our preliminary data is a low-latitude cluster of VGPs that lies near the Late Ordovician overprint VGPs from Swedish limestones (after rotation into a North American reference frame). Other workers have previously interpreted these Baltic VGPs to reflect the collision between East Avalonia and Baltica during closure of the Tornquist Sea. Peeling away the overprints reveals a possible primary direction in 620 Ma rocks of the Mira terrane. Three pilot samples from two sites show normal and reverse polarity and a positive tilt test. VGPs from these samples resemble the VGP obtained from the 609 Ma Dedham Granite in Boston, Massachusetts.

Characterisation of the n-colour printing process using the spot colour overprint model.

PubMed

Deshpande, Kiran; Green, Phil; Pointer, Michael R

2014-12-29

This paper is aimed at reproducing the solid spot colours using the n-colour separation. A simplified numerical method, called as the spot colour overprint (SCOP) model, was used for characterising the n-colour printing process. This model was originally developed for estimating the spot colour overprints. It was extended to be used as a generic forward characterisation model for the n-colour printing process. The inverse printer model based on the look-up table was implemented to obtain the colour separation for n-colour printing process. Finally the real-world spot colours were reproduced using 7-colour separation on lithographic offset printing process. The colours printed with 7 inks were compared against the original spot colours to evaluate the accuracy. The results show good accuracy with the mean CIEDE2000 value between the target colours and the printed colours of 2.06. The proposed method can be used successfully to reproduce the spot colours, which can potentially save significant time and cost in the printing and packaging industry.

Seismicity of the St. Lawrence paleorift faults overprinted by a meteorite impact crater: Implications for crustal strength based on new earthquake relocations in the Charlevoix Seismic Zone, Eastern Canada

NASA Astrophysics Data System (ADS)

Yu, H.; Harrington, R. M.; Liu, Y.; Lamontagne, M.; Pang, M.

2015-12-01

The Charlevoix Seismic Zone (CSZ), located along the St. Lawrence River (SLR) ~100 km downstream from Quebec City, is the most active seismic zone in eastern Canada with five historic earthquakes of M 6-7 and ~ 200 events/year reported by the Canadian National Seismograph Network. Cataloged earthquake epicenters outline two broad linear zones along the SLR with little shallow seismicity in between. Earthquakes form diffuse clusters between major dipping faults rather than concentrating on fault planes. Detailed fault geometry in the CSZ is uncertain and the effect on local seismicity of a meteorite impact structure that overprints the paleorift faults remains ambiguous. Here we relocate 1639 earthquakes occurring in the CSZ between 01/1988 - 10/2010 using the double-difference relocation method HypoDD and waveforms primarily from 7 local permanent stations. We use the layered SLR north shore velocity model from Lamontagne (1999), and travel time differences based on both catalog and cross-correlated P and S-phase picks. Of the 1639 relocated earthquakes, 1236 (75.4%) satisfied selection criteria of horizontal and vertical errors less than 2 km and 1 km respectively. Cross-sections of relocated seismicity show hypocenters along distinct active fault segments. Earthquakes located beneath the north shore of the SLR are likely correlated with the NW Gouffre fault, forming a ~10 km wide seismic zone parallel to the river, with dip angle changing to near vertical at the northern edge of the impact zone. In contrast, seismicity beneath the SLR forms a diffuse cloud within the impact structure, likely representing a highly fractured volume. It further implies that faults could be locally weak and subject to high pore-fluid pressures. Seismicity outside the impact structure defines linear structures aligning with the Charlevoix fault. Relocated events of M > 4 all locate outside the impact structure, indicating they nucleated on the NE-SW-oriented paleorift faults.

Evidence for fourth generation structures in the Piedra Lumbre region, Western Picuris Mountains, New Mexico

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

Chernoff, C.B.; Helper, M.A.; Mosher, S.

1993-02-01

Mid-Proterozoic Hondo Group metasediments in the western Picuris Mountains, New Mexico clearly display 3 generations of previously recognized penetrative, synmetamorphic structures and a previously undocumented forth generation of overprinting folds with an associated axial planar foliation. The earliest structures include: (1) a bedding-parallel S[sub 1] foliation and rare, rootless, intrafolial F[sub 1] folds; (2) north-verging, west-trending F[sub 2] folds and an axial planar metamorphic foliation (S[sub 2]); (3) a steeply dipping, N-S striking crenulation cleavage (S[sub 3]). In the Piedra Lumbre region, southwest-plunging, open, upright chevron and box folds (F[sub 4]) locally reorient F[sub 2], S[sub 2] and S[sub 3]more » crenulations. The largest F[sub 4] folds in the Piedra Lumbre region have half-wavelengths of 500 meters. An associated nearly vertical foliation (S[sub 4]) overprints the first three foliations. The S[sub 4] foliation is a crenulation cleavage in micaceous layers and a discontinuous alignment of biotite laths in quartzose layers. Crystallization of biotite during S[sub 4] and chloritoid after S[sub 4], along with static recrystallization and mineral replacement by chlorite, suggests this deformation occurred during the waning stages of mid-Proterozoic metamorphism. The orientation of F[sub 2] and F[sub 4] folds are similar and both appear to occur on a regional scale. Interference of open upright F[sub 4] folds and tight, north-verging, overturned F[sub 2] folds produces a geometry that resembles that of the kilometer-scale Copper Hill Anticline of the western Picuris Mountains, previously interpreted to be solely the result of F[sub 2] folding.« less

Relations between extensional tectonics and magmatism within the Southern Oklahoma aulacogen

NASA Technical Reports Server (NTRS)

Mcconnell, D. A.; Gilbert, M. C.

1985-01-01

Variations in the geometry, distribution and thickness of Cambrian igneous and sedimentary units within southwest Oklahoma are related to a late Proterozoic - early Paleozoic rifting event which formed the Southern Oklahoma aulacogen. These rock units are exposed in the Wichita Mountains, southwest Olkahoma, located on the northern margin of a Proterozoic basin, identified in the subsurface by COCORP reflection data. Overprinting of the Cambrian extensional event by Pennyslvanian tectonism obsured the influence of pre-existing basement structures and contrasting basement lithologies upon the initial development of the aulacogen.

Necessary Conditions for Intraplate Seismic Zones in North America

NASA Astrophysics Data System (ADS)

Thomas, William A.; Powell, Christine A.

2017-12-01

The cause of intraplate seismic zones persists as an important scientific and societal question. Most intraplate earthquakes are concentrated in specific seismic zones along or adjacent to large-scale basement structures (e.g., rifts or sutures at ancient plate boundaries) within continental crust. The major intraplate seismic zones are limited to specific segments and are not distributed along the lengths of the ancient structures. We present a new hypothesis that major intraplate seismic zones are restricted to places where concentrated crustal deformation (CCD) is overprinted on large-scale basement structures. Examples where CCD affects the stability of specific parts of large-scale structures in response to present-day stress conditions include the most active seismic zones in central and eastern North America: Charlevoix, Eastern Tennessee, and New Madrid. Our hypothesis has important implications for the assessment of seismic hazards.

Heterogeneous brittle-ductile deformation at shallow crustal levels under high thermal conditions: The case of a synkinematic contact aureole in the inner northern Apennines, southeastern Elba Island, Italy

NASA Astrophysics Data System (ADS)

Papeschi, Samuele; Musumeci, Giovanni; Mazzarini, Francesco

2017-10-01

We present an example of interaction between magmatism and tectonics at shallow crustal levels. In the Late Miocene the metamorphic units of the eastern Elba Island (northern Apennines) were intruded at very shallow crustal levels by a large pluton (> 60 km2) with the development of an hectometre-sized contact aureole defined by growth of low-pressure/high-temperature mineral assemblages (Pmax < 0.2 GPa, Tmax 650 °C). Structural data show that the contact aureole is associated with a km-sized antiform of the foliation and by several metre- to decametre-thick high-strain domains consisting of strongly foliated rocks containing synkinematic HT/LP mineral assemblages and ductile shear zones of variable thickness. These shear zones are characterized by a mylonitic foliation variably overprinted by cataclasis. Quartz microfabrics indicate that the dynamic crystallization processes progressively changed from grain boundary migration, associated with the thermal peak of contact metamorphism, to subgrain rotation and bulging recrystallization, the latter mostly associated with the cataclastic overprint. These transitions of recrystallization mechanisms in quartz are related to a progressive decrease of temperature during deformation. Deformation accompanied the development and cooling of the contact aureole, which recorded the switch from high temperature ductile to low temperature brittle conditions. The geometry of the studied deformation structures is consistent with the constraints of the regional tectonic evolution and its local interaction with the localized and transient thermal anomaly related to the coeval emplacement of igneous rocks.

Second generation anthropomorphic physical phantom for mammography and DBT: Incorporating voxelized 3D printing and inkjet printing of iodinated lesion inserts

NASA Astrophysics Data System (ADS)

Sikaria, Dhiraj; Musinsky, Stephanie; Sturgeon, Gregory M.; Solomon, Justin; Diao, Andrew; Gehm, Michael E.; Samei, Ehsan; Glick, Stephen J.; Lo, Joseph Y.

2016-03-01

Physical phantoms are needed for the evaluation and optimization of new digital breast tomosynthesis (DBT) systems. Previously, we developed an anthropomorphic phantom based on human subject breast CT data and fabricated using commercial 3D printing. We now present three key advancements: voxelized 3D printing, photopolymer material doping, and 2D inkjet printing of lesion inserts. First, we bypassed the printer's control software in order to print in voxelized form instead of conventional STL surfaces, thus improving resolution and allowing dithering to mix the two photopolymer materials into arbitrary proportions. We demonstrated ability to print details as small as 150μm, and dithering to combine VeroWhitePlus and TangoPlus in 10% increments. Second, to address the limited attenuation difference among commercial photopolymers, we evaluated a beta sample from Stratasys with increased TiO2 doping concentration up to 2.5%, which corresponded to 98% breast density. By spanning 36% to 98% breast density, this doubles our previous contrast. Third, using inkjet printers modified to print with iopamidol, we created 2D lesion patterns on paper that can be sandwiched into the phantom. Inkjet printing has advantages of being inexpensive and easy, and more contrast can be delivered through overprinting. Printing resolution was maintained at 210 μm horizontally and 330 μm vertically even after 10 overprints. Contrast increased linearly with overprinting at 0.7% per overprint. Together, these three new features provide the basis for creating a new anthropomorphic physical breast phantom with improved resolution and contrast, as well as the ability to insert 2D lesions for task-based assessment of performance.

Evidence for the recent origin of a bacterial protein-coding, overlapping orphan gene by evolutionary overprinting.

PubMed

Fellner, Lea; Simon, Svenja; Scherling, Christian; Witting, Michael; Schober, Steffen; Polte, Christine; Schmitt-Kopplin, Philippe; Keim, Daniel A; Scherer, Siegfried; Neuhaus, Klaus

2015-12-18

Gene duplication is believed to be the classical way to form novel genes, but overprinting may be an important alternative. Overprinting allows entirely novel proteins to evolve de novo, i.e., formerly non-coding open reading frames within functional genes become expressed. Only three cases have been described for Escherichia coli. Here, a fourth example is presented. RNA sequencing revealed an open reading frame weakly transcribed in cow dung, coding for 101 residues and embedded completely in the -2 reading frame of citC in enterohemorrhagic E. coli. This gene is designated novel overlapping gene, nog1. The promoter region fused to gfp exhibits specific activities and 5' rapid amplification of cDNA ends indicated the transcriptional start 40-bp upstream of the start codon. nog1 was strand-specifically arrested in translation by a nonsense mutation silent in citC. This Nog1-mutant showed a phenotype in competitive growth against wild type in the presence of MgCl2. Small differences in metabolite concentrations were also found. Bioinformatic analyses propose Nog1 to be inner membrane-bound and to possess at least one membrane-spanning domain. A phylogenetic analysis suggests that the orphan gene nog1 arose by overprinting after Escherichia/Shigella separated from the other γ-proteobacteria. Since nog1 is of recent origin, non-essential, short, weakly expressed and only marginally involved in E. coli's central metabolism, we propose that this gene is in an initial stage of evolution. While we present specific experimental evidence for the existence of a fourth overlapping gene in enterohemorrhagic E. coli, we believe that this may be an initial finding only and overlapping genes in bacteria may be more common than is currently assumed by microbiologists.

Transdomes: Emplacement of Migmatite Domes in Oblique Tectonic Settings

NASA Astrophysics Data System (ADS)

Teyssier, C. P.; Rey, P. F.; Whitney, D. L.; Mondy, L. S.; Roger, F.

2014-12-01

Many migmatite domes are emplaced within wrench corridors in which a combination of strike-slip and extensional detachment zones (pull-apart, extensional relay, or transfer zones) focus deep-crust exhumation. The Montagne Noire dome (France, Variscan Massif Central) exemplifies wrench-related dome formation and displays the following structural, metamorphic, and geochronologic characteristics of a 'transdome': the dome is elongate in the direction of extension; foliation outlines a double dome separated by a high-strain zone; lineation is shallowly plunging with a fairly uniform trend that parallels the strike of the high-strain zone; subdomes contain recumbent structures overprinted by upright folds that affected upward by flat shear zones associated with detachment tectonics; domes display a large syn-deformation metamorphic gradient from core (upper amphibolite facies migmatite) to margin (down to greenschist facies mylonite); some rocks in the dome core experienced isothermal decompression revealed by disequilibrium reaction textures, particularly in mafic rocks (including eclogite); and results of U-Pb geochrononology indicate a narrow range of metamorphic crystallization from core to mantling schist spanning ~10 Myr. 3D numerical modeling of transdomes show that the dome solicits a larger source region of partially molten lower crust compared to 2D models; this flowing crust creates a double-dome architecture as in 2D models but there are differences in the predicted thermal history and flow paths. In a transtension setting, flow lines converge at depth (radial-centripetal flow) toward the zone of extension and diverge at shallow levels in a more uniform direction that is imposed by upper crust motion and deformation. This evolution produces a characteristic pattern of strain history, progressive fabric overprint, and P-T paths that are comparable to observed dome rocks.

Post-depositional tectonic modification of VMS deposits in Iberia and its economic significance

NASA Astrophysics Data System (ADS)

Castroviejo, Ricardo; Quesada, Cecilio; Soler, Miguel

2011-07-01

The original stratigraphic relationships and structure of VMS deposits are commonly obscured by deformation. This can also affect their economic significance, as shown by several Iberian Pyrite Belt (IPB, SW Iberia) examples. The contrasting rheologic properties of the different lithologies present in an orebody (massive sulphide, feeder stockwork, alteration envelope, volcanic and sedimentary rocks) play a major role in determining its overall behaviour. Variscan thin-skinned tectonics led to stacking of the massive pyrite and stockwork bodies in duplex structures, resulting in local thickening and increased tonnage of minable mineralization. Furthermore, differential mechanical behaviour of the different sulphide minerals localised the detachments along relatively ductile sulphide-rich bands. The result was a geochemical and mineralogical reorganisation of most deposits, which now consist of barren, massive pyrite horses, bounded by base metal-rich ductile shear zones. Metal redistribution was enhanced by mobilisation of the base metal sulphides from the initially impoverished massive pyrite, through pressure-solution processes, to tensional fissures within the already ductile shear zones. In NW Iberia, VMS deposits were also strongly overprinted by the Variscan deformation during emplacement of the Cabo Ortegal and Órdenes allochthonous nappe complexes, but no stacking of the orebodies was produced. Original contacts were transposed, and the orebodies, their feeder zones and the country rock acquired pronounced laminar geometry. In lower-grade rocks (greenschist facies, Cabo Ortegal Complex), solution transfer mechanisms are common in pyrite, which remains in the brittle domain, while chalcopyrite shows ductile behaviour. In higher-grade rocks (amphibolite facies, Órdenes Complex), metamorphic recrystallisation overprints earlier deformation textures. The contrasting behaviour of the IPB and NW Iberian deposits is explained by key factors that affect their final geometry, composition and economics, such as pre-deformation structure, size and mineralogical composition of the orebody and associated lithologies, temperature, crustal level, deviatoric stress and availability of a fluid phase during deformation and the style and rate of deformation.

Impact effects and regional tectonic insights: Backstripping the Chesapeake Bay impact structure

USGS Publications Warehouse

Hayden, T.; Kominz, M.; Powars, D.S.; Edwards, L.E.; Miller, K.G.; Browning, J.V.; Kulpecz, A.A.

2008-01-01

The Chesapeake Bay impact structure is a ca. 35.4 Ma crater located on the eastern seaboard of North America. Deposition returned to normal shortly after impact, resulting in a unique record of both impact-related and subsequent passive margin sedimentation. We use backstripping to show that the impact strongly affected sedimentation for 7 m.y. through impact-derived crustal-scale tectonics, dominated by the effects of sediment compaction and the introduction and subsequent removal of a negative thermal anomaly instead of the expected positive thermal anomaly. After this, the area was dominated by passive margin thermal subsidence overprinted by periods of regional-scale vertical tectonic events, on the order of tens of meters. Loading due to prograding sediment bodies may have generated these events. ?? 2008 The Geological Society of America.

Unravelling the structural control of mississippi valley-type deposits and prospects in carbonate sequences of the Western Canada Sedimentary Basin

USGS Publications Warehouse

Pana, D.

2006-01-01

Re-examination of selected MVT outcrops and cores in the Interior Plains and Rocky Moun-tains of Alberta, corroborated with previous paragenetic, isotopic and structural data, suggests Laramide structural channelling of dolomitizing and mineralizing fluids into strained carbonate rocks. At Pine Point, extensional faults underlying the trends of MVT ore bodies and brittle faults overprinting the Great Slave Lake Shear Zone define apinnate fault geometry and appear to be kinematically linked. Chemical and isotopic characteristics of MVT parental fluids are consistent with seawater and brine convection within fault-confined verticalaquifers, strong water-basement rock interaction, metalleaching from the basement, and focused release of hydrothermal fluids within linear zones of strained carbonate caprocks. Zones of recurrent strain in the basement and a cap of carbonate strata constitute the critical criteria for MVTexploration target selection in the WCSB.

Intensive low-temperature tectono-hydrothermal overprint of peraluminous rare-metal granite: a case study from the Dlhá dolina valley (Gemericum, Slovakia)

NASA Astrophysics Data System (ADS)

Breiter, Karel; Broska, Igor; Uher, Pavel

2015-02-01

A unique case of low-temperature metamorphic (hydrothermal) overprint of peraluminous, highly evolved rare-metal S-type granite is described. The hidden Dlhá dolina granite pluton of Permian age (Western Carpathians, eastern Slovakia) is composed of barren biotite granite, mineralized Li-mica granite and albitite. Based on whole-rock chemical data and evaluation of compositional variations of rock-forming and accessory minerals (Rb-P-enriched K-feldspar and albite; biotite, zinnwaldite and di-octahedral micas; Hf-(Sc)-rich zircon, fluorapatite, topaz, schorlitic tourmaline), the following evolutionary scenario is proposed: (1) Intrusion of evolved peraluminous melt enriched in Li, B, P, F, Sn, Nb, Ta, and W took place followed by intrusion of a large body of biotite granites into Paleozoic metapelites and metarhyolite tuffs; (2) The highly evolved melt differentiated in situ forming tourmaline-bearing Li-biotite granite at the bottom, topaz-zinnwaldite granite in the middle, and quartz albitite to albitite at the top of the cupola. The main part of the Sn, Nb, and Ta crystallized from the melt as disseminated cassiterite and Nb-Ta oxide minerals within the albitite, while disseminated wolframite appears mainly within the topaz-zinnwaldite granite. The fluid separated from the last portion of crystallized magma caused small scale greisenization of the albitite; (3) Alpine (Cretaceous) thrusting strongly tectonized and mylonitized the upper part of the pluton. Hydrothermal low-temperature fluids enriched in Ca, Mg, and CO2 unfiltered mechanically damaged granite. This fluid-driven overprint caused formation of carbonate veinlets, alteration and release of phosphorus from crystal lattice of feldspars and Li from micas, precipitating secondary Sr-enriched apatite and Mg-rich micas. Consequently, all bulk-rock and mineral markers were reset and now represent the P-T conditions of the Alpine overprint.

Disclosing the Paleoarchean to Ediacaran history of the São Francisco craton basement: The Porteirinha domain (northern Araçuaí orogen, Brazil)

NASA Astrophysics Data System (ADS)

Silva, Luiz Carlos da; Pedrosa-Soares, Antonio Carlos; Armstrong, Richard; Pinto, Claiton Piva; Magalhães, Joana Tiago Reis; Pinheiro, Marco Aurélio Piacentini; Santos, Gabriella Galliac

2016-07-01

This geochronological and isotopic study focuses on one of the Archean-Paleoproterozoic basement domains of the São Francisco craton reworked in the Araçuaí orogen, the Porteirinha domain, Brazil. It also includes a thorough compilation of the U-Pb geochronological data related to the adjacent Archean and Rhyacian terranes from the São Francisco craton and Araçuaí orogen. The main target of this study is the TTG gneisses of the Porteirinha complex (Sample 1). The gneiss dated at 3371 ± 6 Ma unraveled a polycyclic evolution characterized by two metamorphic overprinting episodes, dated at 3146 ± 24 Ma (M1) and ca. 600 Ma (M2). The former (M1) is so far the most reliable evidence of the oldest metamorphic episode ever dated in Brazil. The latter (M2), in turn, is endemic in most of the exposed eastern cratonic margin within the Araçuaí orogen. Whole-rock Sm-Nd analysis from the gneiss provided a slightly negative εNd(t3370) = - 0.78 value, and a depleted mantle model (TDM) age of 3.5 Ga, indicating derivation mainly from the melting of a ca. 3.5 Ga tholeiitic source. Sample 2, a K-rich leuco-orthogneiss from the Rio Itacambiriçu Complex, was dated at 2657 ± 25 Ma and also presents a ca. 600 Ma M2 overprinting M2 age. The other two analyses were obtained from Rhyacian granitoids. Sample 3 is syn-collisional, peraluminous leucogranite from the Tingui granitic complex, showing a crystallization age of 2140 ± 14 Ma and strong post-crystallization Pb*-loss, also ascribed to the Ediacaran overprinting. Accordingly, it is interpreted as a correlative of the late Rhyacian (ca. 2150-2050 Ma) collisional stage of the Mantiqueira orogenic system/belt (ca. 2220-2000 Ma), overprinted by the Ediacaran collage. Sample 4 is a Rhyacian post-orogenic (post-collisional), mixed-source, peralkaline, A1-type suite, with a crystallization age of 2050 ± 10 Ma, presenting an important post-crystallization Pb*-loss related to Ediacaran collision. The focused region records some of the oldest magmatic and metamorphic events ever found in the São Francisco craton basement, a ca. 3.4 Ga TTG generation and ca. 3.1 Ga metamorphism, as well as two younger orogenic events: the Rhyacian (2.15-2.05 Ga), accretionary event, correlated to the Mineiro belt, and the Ediacaran Brasiliano overprinting, event imposed by the Araçuaí orogen.

Transpressional regime in southern Arabian Shield: Insights from Wadi Yiba Area, Saudi Arabia

NASA Astrophysics Data System (ADS)

Hamimi, Zakaria; El-Shafei, Mohamed; Kattu, Ghazi; Matsah, Mohammed

2013-10-01

Detailed field-structural mapping of Neoproterozoic basement rocks exposed in the Wadi Yiba area, southern Arabian Shield, Saudi Arabia illustrates an important episode of late Neoproterozoic transpression in the southern part of the Arabian-Nubian Shield (ANS). This area is dominated by five main basement lithologies: gneisses, metavolcanics, Ablah Group (meta-clastic and marble units) and syn- and post-tectonic granitoids. These rocks were affected by three phases of deformation (D1-D3). D1 formed tight to isoclinal and intrafolial folds (F1), penetrative foliation (S1), and mineral lineation (L1), which resulted from early E-W (to ENE-WSW) shortening. D2 deformation overprinted D1 structures and was dominated by transpression and top-to-the-W (-WSW) thrusting as shortening progressed. Stretching lineation trajectories, S-C foliations, asymmetric shear fabrics and related mylonitic foliation, and flat-ramp and duplex geometries further indicate the inferred transport direction. The N- to NNW-orientation of both “in-sequence piggy-back thrusts” and axial planes of minor and major F2 thrust-related overturned folds also indicates the same D2 compressional stress trajectories. The Wadi Yiba Shear Zone (WYSZ) formed during D2 deformation. It is one of several N-S trending brittle-ductile Late Neoproterozoic shear zones in the southern part of the ANS. Shear sense indicators reveal that shearing during D2 regional-scale transpression was dextral and is consistent with the mega-scale sigmoidal patterns recognized on Landsat images. The shearing led to the formation of the WYSZ and consequent F2 shear zone-related folds, as well as other unmappable shear zones in the deformed rocks. Emplacement of the syn-tectonic granitoids is likely to have occurred during D2 transpression and occupied space created during thrust propagation. D1 and D2 structures are locally overprinted by mesoscopic- to macroscopic-scale D3 structures (F3 folds, and L3 crenulation lineations and kink bands). F3 folds are frequently open and have steep to subvertical axial planes and axes that plunge ENE to ESE. This deformation may reflect progressive convergence between East and West Gondwana.

Mid-Cretaceous oblique rifting of West Antarctica: Emplacement and rapid cooling of the Fosdick Mountains migmatite-cored gneiss dome

USGS Publications Warehouse

McFadden, Rory; Teyssier, Christian; Siddoway, Christine; Cosca, Michael A.; Fanning, C. Mark

2015-01-01

In Marie Byrd Land, West Antarctica, the Fosdick Mountains migmatite-cored gneiss dome was exhumed from mid- to lower middle crustal depths during the incipient stage of the West Antarctic Rift system in the mid-Cretaceous. Prior to and during exhumation, major crustal melting and deformation included transfer and emplacement of voluminous granitic material and numerous intrusions of mantle-derived diorite in dikes. A succession of melt- and magma-related structures formed at temperatures in excess of 665 ± 50 °C based on Ti-in-zircon thermometry. These record a transition from wrench to oblique extensional deformation that culminated in the development of the oblique South Fosdick Detachment zone. Solid-state fabrics within the detachment zone and overprinting brittle structures record translation of the detachment zone and dome to shallow levels.To determine the duration of exhumation and cooling, we sampled granite and gneisses at high spatial resolution for U–Pb zircon geochronology and 40Ar/39Ar hornblende and biotite thermochronology. U–Pb zircon crystallization ages for the youngest granites are 102 Ma. Three hornblende ages are 103 to 100 Ma and 12 biotite ages are 101 to 99 Ma. All overlap within uncertainty. The coincidence of zircon crystallization ages with 40Ar/39Ar cooling ages indicates cooling rates > 100 °C/m.y. that, when considered together with overprinting structures, indicates rapid exhumation of granite and migmatite from deep to shallow crustal levels within a transcurrent setting. Orientations of structures and age-constrained crosscutting relationships indicate counterclockwise rotation of stretching axes from oblique extension into nearly orthogonal extension with respect to the Marie Byrd Land margin. The rotation may be a result of localized extension arising from unroofing and arching of the Fosdick dome, extensional opening within a pull-apart zone, or changes in plate boundary configuration.The rapid tectonic and temperature evolution of the Fosdick Mountains dome lends support to recently developed numerical models of crustal flow and cooling in orogenic crust undergoing extension/transtension, and accords with numerous studies of migmatite-cored gneiss domes in transcurrent settings.

Reversed structures and bounce structures: are they recognizable? Are they real?

NASA Astrophysics Data System (ADS)

Means, W. D.

1999-08-01

This note poses two related questions about structural evolution in rocks. How easy is it to recognize structural features that have reversed their sense of development over time? Are there circumstances in rock deformation where early intensification of structure sows the seeds for a later, more or less inevitable, diminution of intensity? It is suggested, as a partial answer to the first question, that there is an irreversibility principle inherent to most structural development, such that even if bulk strain is reversed, the structural changes that accompanied `forward' structural development will not be completely reversed when the strain is reversed. Where this principle applies, it should always be possible to recognize structural reversals, by sufficiently close observation of the final state. It is suggested, as a partial answer to the second question, that where energy is stored by forward structural changes, this energy can often be expected to drive further structural changes, and these further changes may sometimes cause the original structure to `bounce' back to a less intense state. These questions may have some bearing on developing a firmer basis for kinematic analysis, and for understanding overprinting structures in orogens.

Structures, microfabrics, fractal analysis and temperature-pressure estimation of the Mesozoic Xingcheng-Taili ductile shear zone in the North China craton

NASA Astrophysics Data System (ADS)

Liang, Chenyue; Neubauer, Franz; Liu, Yongjiang; Jin, Wei; Zeng, Zuoxun; Bernroider, Manfred; Li, Weimin; Wen, Quanbo; Han, Guoqing; Zhao, Yingli

2014-05-01

The ductile shear zone in Xingcheng-Taili area (western Liaoning Province in China) is tectonically located in the eastern section of the northern margin of the North China craton, and dominantly comprises deformed granitic rocks of Neoarchean and Triassic to Late Jurassic age, which were affected by shearing within middle- to low-grade metamorphic conditions. Because a high-temperature metamorphic overprint is lacking, microstructures attesting to low-temperature ductile deformation are well preserved. However, the rocks and its structures have not been previously analyzed in detail except by U-Pb zircon dating and some geochemistry. Here, we describe the deformation characteristics and tectonic evolution of the Xingcheng-Taili ductile shear zone, in order to understand the mode of lithosphericscale reactivation, extension and thinning of the North China craton. The ductile deformation history comprises four successive deformation phases: (1) In the Neoarchean granitic rocks, a steep gneissosity and banded structures trend nearly E-W (D1). (2) A NE-striking sinistral structure of Upper Triassic rocks may indicate a deformation event (D2) in Late Triassic times, which ductile deformation structures superimposed on Neoarchean granitic rocks. (3) A gneissose structure with S-C fabrics as well as an ENE-trending sinistral strike-slip characteristic (D3) developed in Upper Jurassic biotite adamellite and show the deformation characteristics of a shallow crustal level and generated mylonitic fabrics superimposed on previous structures. (4) Late granitic dykes show different deformational behavior, and shortening with D4 folds. The attitude of the foliation S and mineral stretching lineation of three main types of rocks shows remarkable differences in orientation. The shapes of recrystallized quartz grains from three main types of granitic rocks with their jagged and indented boundaries were natural records of deformation conditions (D1to D3). Crystal preferred orientation of quartz determined by electron back scatter diffraction (EBSD) suggest sinistral strike-slip displacement within a temperature at about 400 to 500° C. Quartz mainly shows low-temperature fabrics with dominant {0001}-slip system. As the deformed rocks show obvious deformation overprint, we have estimated flow stresses from dynamically recrystallized grain sizes of quartz separately. But coincident fractal analysis showed that the boundaries of recrystallized grains had statistically self similarities with the numbers of fractal dimension from 1.153 to 1.196 with the range of deformation temperatures from 500 to 600° C, which is corresponding to upper greenschist to lower amphibolite facies conditions. Together with published flow laws to estimated deformation rates between the region of 10-11 - 10-13 S-1depending on the temperature 500 ° C, and the paleo-stress was calculated with grain size of recrystallized quartz to be at 5.0 to 32.3 MPa. Even though the deformation history and kinematics are different, progressive microstructures and texture analysis indicate an overprint by the low-temperature deformation (D3). Typical regional-dynamic metamorphic conditions ere deduced by mineral pair hornblende-plagioclase and phengite barometry identified within the ductile shear zone. The hornblende-plagioclase pair of porphyritic granitic gneiss gives metamorphic conditions of T =450-500 ° C and p=0.39 GPa, which indicate a metamorphic grade of lower-amphibolite facies conditions and a depth of around 13 km estimated following a normal lithostatic pressure. All of the structural characteristics indicate that the Xingcheng-Taili ductile shear zone represents a mainly ENE-striking sinistral ductile strike-slip zone, which formed after intrusion of the Upper Jurassic biotite adamellite and transformed and superimposed previous deformation structures. This deformation event might have occurred in Early Cretaceous times and was related to the lithospheric thinning and extension, due to roll-back of the Pacific plate beneath the eastern North China craton.

Late Miocene remagnetization within the internal sector of the Northern Apennines, Italy

USGS Publications Warehouse

Aiello, I.W.; Hagstrum, J.T.; Principi, G.

2004-01-01

Paleomagnetic and geologic evidence indicates that Upper Jurassic radiolarian cherts of both the Tuscan Cherts Formation (continental margin, Tuscan Units) and the Monte Alpe Cherts Formation (oceanic crust, Ligurian Units) were remagnetized during Miocene orogenesis of the Northern Apennines of Italy. Characteristic overprint magnetizations with reversed polarities have been found over a large area within the internal sector of the Northern Apennines, including eastern Liguria, Elba Island and the Thyrrenian margin, and west of the Middle Tuscan Ridge. The reversed-polarity overprint (average direction: D=177??, I=-52??, ??95=15??) was most likely acquired during Late Miocene uplift and denudation of the orogenic chain, and thermochemical remagnetization was a probable consequence of increased circulation of orogenic fluids. Similarly, mostly reversed-polarity directions of magnetization have been found by other workers in overlying post-orogenic Messinian sediments (D=177??, I=-57??, ??95=3??), which show little counterclockwise (CCW) vertical-axis rotation with respect to stable Europe (-8??5??). The Monte Alpe Cherts sampled at sites in the external sector of the Northern Apennines, close to major tectonic features, have normal- polarity overprint directions with in situ W-SW declinations. Since the overlying post-orogenic Messinian sediments have not been substantially rotated about vertical axes, the evidence points to an earlier,pre-Late Miocene remagnetization in the external parts of the orogenic chain. ?? 2004 Elsevier B.V. All rights reserved.

Origins of Genes: "Big Bang" or Continuous Creation?

NASA Astrophysics Data System (ADS)

Kesse, Paul K.; Gibbs, Adrian

1992-10-01

Many protein families are common to all cellular organisms, indicating that many genes have ancient origins. Genetic variation is mostly attributed to processes such as mutation, duplication, and rearrangement of ancient modules. Thus it is widely assumed that much of present-day genetic diversity can be traced by common ancestry to a molecular "big bang." A rarely considered alternative is that proteins may arise continuously de novo. One mechanism of generating different coding sequences is by "overprinting," in which an existing nucleotide sequence is translated de novo in a different reading frame or from noncoding open reading frames. The clearest evidence for overprinting is provided when the original gene function is retained, as in overlapping genes. Analysis of their phylogenies indicates which are the original genes and which are their informationally novel partners. We report here the phylogenetic relationships of overlapping coding sequences from steroid-related receptor genes and from tymovirus, luteovirus, and lentivirus genomes. For each pair of overlapping coding sequences, one is confined to a single lineage, whereas the other is more widespread. This suggests that the phylogenetically restricted coding sequence arose only in the progenitor of that lineage by translating an out-of-frame sequence to yield the new polypeptide. The production of novel exons by alternative splicing in thyroid receptor and lentivirus genes suggests that introns can be a valuable evolutionary source for overprinting. New genes and their products may drive major evolutionary changes.

48 CFR 1815.404-471 - NASA structured approach for profit or fee objective.

Code of Federal Regulations, 2010 CFR

2010-10-01

... NATIONAL AERONAUTICS AND SPACE ADMINISTRATION CONTRACTING METHODS AND CONTRACT TYPES CONTRACTING BY NEGOTIATION Contract Pricing 1815.404-471 NASA structured approach for profit or fee objective. ...

The family Rhabdoviridae: Mono- and bipartite negative-sense RNA viruses with diverse genome organization and common evolutionary origins

USGS Publications Warehouse

Dietzgen, Ralf G.; Kondo, Hideki; Goodin, Michael M.; Kurath, Gael; Vasilakis, Nikos

2017-01-01

The family Rhabdoviridae consists of mostly enveloped, bullet-shaped or bacilliform viruses with a negative-sense, single-stranded RNA genome that infect vertebrates, invertebrates or plants. This ecological diversity is reflected by the diversity and complexity of their genomes. Five canonical structural protein genes are conserved in all rhabdoviruses, but may be overprinted, overlapped or interspersed with several novel and diverse accessory genes. This review gives an overview of the characteristics and diversity of rhabdoviruses, their taxonomic classification, replication mechanism, properties of classical rhabdoviruses such as rabies virus and rhabdoviruses with complex genomes, rhabdoviruses infecting aquatic species, and plant rhabdoviruses with both mono- and bipartite genomes.

Geological Mapping of the North Polar Region of Venus (V-1 Snegurochka Planitia): Significant Problems and Comparisons to the Earth's Archean

NASA Technical Reports Server (NTRS)

Head, James W.; Hurwitz, D. M.; Ivanov, M. A.; Basilevsky, A. T.; Kumar, P. Senthil

2008-01-01

The geological features, structures, thermal conditions, interpreted processes, and outstanding questions related to both the Earth's Archean and Venus share many similarities and we are using a problem-oriented approach to Venus mapping, guided by perspectives from the Archean record of the Earth, to gain new insight into both. The Earth's preserved and well-documented Archean record provides important insight into high heat-flux tectonic and magmatic environments and structures and Venus reveals the current configuration and recent geological record of analogous high-temperature environments unmodified by subsequent several billion years of segmentation and overprinting, as on Earth. We have problems on which progress might be made through comparison. Here we present the major goals of the geological mapping of the V-1 Snegurochka Planitia Quadrangle, and themes that could provide important insights into both planets:

Differentiating pedogenesis from diagenesis in early terrestrial paleoweathering surfaces formed on granitic composition parent materials

USGS Publications Warehouse

Driese, S.G.; Medaris, L.G.; Ren, M.; Runkel, Anthony C.; Langford, R.P.

2007-01-01

Unconformable surfaces separating Precambrian crystalline basement and overlying Proterozoic to Cambrian sedimentary rocks provide an exceptional opportunity to examine the role of primitive soil ecosystems in weathering and resultant formation of saprolite (weathered rock retaining rock structure) and regolith (weathered rock without rock structure), but many appear to have been affected by burial diagenesis and hydrothermal fluid flow, leading some researchers to discount their suitability for such studies. We examine one modern weathering profile (Cecil series), four Cambrian paleoweathering profiles from the North American craton (Squaw Creek, Franklin Mountains, Core SQ-8, and Core 4), one Neoproterozoic profile (Sheigra), and one late Paleoproterozoic profile (Baraboo), to test the hypothesis that these paleoweathering profiles do provide evidence of primitive terrestrial weathering despite their diagenetic and hydrothermal overprinting, especially additions of potassium. We employ an integrated approach using (1) detailed thin-section investigations to identify characteristic pedogenic features associated with saprolitization and formation of well-drained regoliths, (2) electron microprobe analysis to identify specific weathered and new mineral phases, and (3) geochemical mass balance techniques to characterize volume changes during weathering and elemental gains and losses of major and minor elements relative to the inferred parent materials. There is strong pedogenic evidence of paleoweathering, such as clay illuviation, sepic-plasmic fabrics, redoximorphic features, and dissolution and alteration of feldspars and mafic minerals to kaolinite, gibbsite, and Fe oxides, as well as geochemical evidence, such as whole-rock losses of Na, Ca, Mg, Si, Sr, Fe, and Mn greater than in modern profiles. Evidence of diagenesis includes net additions of K, Ba, and Rb determined through geochemical mass balance, K-feldspar overgrowths in overlying sandstone sections, and K-feldspars with reaction rims in weathered basement. The sub-Cambrian paleoweathering profiles formed on granite are remarkably similar to modern weathering profiles formed on granite, in spite of overprinting by potassium diagenesis. ?? 2007 by The University of Chicago. All rights reserved.

Preserved magnetic fabrics vs. annealed microstructures in the syntectonic recrystallised George granite, South Africa

NASA Astrophysics Data System (ADS)

Ferré, E. C.; Améglio, L.

2000-08-01

The Saldanian basement of the Cape Fold Belt of South Africa outcrops in the Kaaimans inlier with granite plutons intruded in low-grade pelitic and quartzitic metasediments around 535 Ma. New field data support a ubiquitous Saldanian top-to-the-north thrust kinematics coeval with granite emplacement with no substantial Cape tectonic overprint. The granites and their contact aureoles display both synkinematic and post-kinematic fabrics. This and the high strain zone commonly observed all along the contact between the Kaaimans inlier and the Cape Fold Belt, suggest a structural decoupling between the basement and its cover. Microstructures in the Kaaimans inlier and in the George pluton establish a post-kinematic, pervasive and thermal overprint of Saldanian age. Granites and country rocks record a medium-temperature/high-strain deformation phase followed by a strong low-temperature/static recrystallisation. Two sets of andalusite porphyroblasts occur systematically in the contact aureoles of the studied plutons and cannot be explained by successive magmatic pulses. The granites, studied by the Anisotropy of Magnetic Susceptibility (AMS) technique, are paramagnetic (20< Km<300 μSI). Biotite is mostly at the origin of the bulk rock susceptibility although minor contributions of tourmaline or ferromagnetic phases may occur. The contribution of biotite alone to the bulk magnetic susceptibility is supported by two quantitative models based, respectively, on whole rock compositions (Curie-Weiss law) and on intrinsic mineral susceptibilities. The magnetic foliations and lineations are homogeneous throughout the George pluton and are consistent with field structures. The AMS results mainly from the magneto-crystalline anisotropy of biotite and from its lattice preferred orientation (LPO) in the rock. The magnetic fabric reveals the biotite subfabrics that had been acquired before static recrystallisation and which was not modified by the subsequent thermal metamorphic event. The magnetic fabric therefore preserves the emplacement-related deformation fabric.

Submarine hydrothermal metamorphism of the Del Puerto ophiolite, California.

USGS Publications Warehouse

Evarts, R.C.; Schiffman, P.

1983-01-01

Metamorphic zonation overprinted on the volcanic member and overlying volcanogenic sediments of the ophiolite complex increases downward in grade and is characterized by the sequential appearance with depth of zeolites, ferric pumpellyite and pistacitic epidote. Metamorphic assemblages of the plutonic member of the complex are characterized by the presence of calcic amphibole. The overprinting represents the effects of hydrothermal metamorphism resulting from the massive interaction between hot igneous rocks and convecting sea-water in a submarine environment. A thermal gradient of 100oC/km is postulated to account for the zonal recrystallization effects in the volcanic member. The diversity and sporadic distribution of mineral assemblages in the amphibole zone are considered due to the limited availability of H2O in the deeper part of the complex. Details of the zonation and representative microprobe analyses are tabulated.-M.S.

Forensic analysis of laser printed ink by X-ray fluorescence and laser-excited plume fluorescence.

PubMed

Chu, Po-Chun; Cai, Bruno Yue; Tsoi, Yeuk Ki; Yuen, Ronald; Leung, Kelvin S Y; Cheung, Nai-Ho

2013-05-07

We demonstrated a minimally destructive two-tier approach for multielement forensic analysis of laser-printed ink. The printed document was first screened using a portable-X-ray fluorescence (XRF) probe. If the results were not conclusive, a laser microprobe was then deployed. The laser probe was based on a two-pulse scheme: the first laser pulse ablated a thin layer of the printed ink; the second laser pulse at 193 nm induced multianalytes in the desorbed ink to fluoresce. We analyzed four brands of black toners. The toners were printed on paper in the form of patches or letters or overprinted on another ink. The XRF probe could sort the four brands if the printed letters were larger than font 20. It could not tell the printing sequence in the case of overprints. The laser probe was more discriminatory; it could sort the toner brands and reveal the overprint sequence regardless of font size while the sampled area was not visibly different from neighboring areas even under the microscope. In terms of general analytical performance, the laser probe featured tens of micrometer lateral resolution and tens to hundreds of nm depth resolution and atto-mole mass detection limits. It could handle samples of arbitrary size and shape and was air compatible, and no sample pretreatment was necessary. It will prove useful whenever high-resolution and high sensitivity 3D elemental mapping is required.

Origins of genes: "big bang" or continuous creation?

PubMed Central

Keese, P K; Gibbs, A

1992-01-01

Many protein families are common to all cellular organisms, indicating that many genes have ancient origins. Genetic variation is mostly attributed to processes such as mutation, duplication, and rearrangement of ancient modules. Thus it is widely assumed that much of present-day genetic diversity can be traced by common ancestry to a molecular "big bang." A rarely considered alternative is that proteins may arise continuously de novo. One mechanism of generating different coding sequences is by "overprinting," in which an existing nucleotide sequence is translated de novo in a different reading frame or from noncoding open reading frames. The clearest evidence for overprinting is provided when the original gene function is retained, as in overlapping genes. Analysis of their phylogenies indicates which are the original genes and which are their informationally novel partners. We report here the phylogenetic relationships of overlapping coding sequences from steroid-related receptor genes and from tymovirus, luteovirus, and lentivirus genomes. For each pair of overlapping coding sequences, one is confined to a single lineage, whereas the other is more widespread. This suggests that the phylogenetically restricted coding sequence arose only in the progenitor of that lineage by translating an out-of-frame sequence to yield the new polypeptide. The production of novel exons by alternative splicing in thyroid receptor and lentivirus genes suggests that introns can be a valuable evolutionary source for overprinting. New genes and their products may drive major evolutionary changes. PMID:1329098

Structural Evolution of a Crustal Scale Tectonic Boundary in the 1 Ga Sveconorwegian Orogen, SW Sweden.

NASA Astrophysics Data System (ADS)

Pinan-Llamas, A.; Möller, C.; Andersson, J.

2016-12-01

We present new structural data to document Sveconorwegian deformational structures preserved in rocks of the Idefjorden Terrane (IT), the Eastern Segment (ES) and a formerly deep-seated tectonic boundary between them, the Mylonite Zone (MZ), in SW Sweden. We aim to integrate structural, petrologic and geochronological data to reconstruct a model for the Sveconorwegian deformation. The SE-vergent MZ is a crustal scale thrust that juxtaposed the allochtonous IT in the hanging wall against the eclogite-bearing ES in the footwall during the Sveconorwegian orogeny. In the research area, rocks of the IT are characterized by a roughly N-S striking tectonic banding that dips shallowly to the W and contains west or WNW-plunging stretching lineations. This gneissic banding is folded by asymmetric and overturned S- or SW-verging similar folds, which in highly strained areas become isoclinal and recumbent. In sections parallel to the lineation, most kinematic indicators are consistent with a top-down-to-the-west sense of shear, i.e. accommodating E-W extension. At the terrane boundary (MZ), ultramylonites and sheath folds are locally present. Immediately east of the MZ, rocks of the ES show a NW-SE to NE-SW striking tectonic banding (Sc) containing shallowly W- and SW-plunging stretching lineations. Sc locally preserves kinematic indicators and intrafolial folds (F1) that we relate to a first Sveconorwegian deformation phase D1. D1 fabrics were folded by asymmetric NE-SW to E-W trending F2 similar folds that are SE- to S-verging. In highly strained areas, these folds are isoclinal and recumbent. The main stretching lineation is sub-parallel to F2 fold axes. In sections subparallel to the lineation, kinematic indicators show a top-down-to-the-west or southwest sense of shear, including extensional shear bands that are overprinting F2 folds. Upright open F3 folds affect earlier fabrics. While D1 fabrics likely resulted from foreland-directed (east-vergent) thrusting that juxtaposed an eclogite-bearing terrane with eclogite-free units in the ES, D2 fabrics (shear-related folds and subsequent shear bands) may be related to E-W or NW-SE extensional or transtensional deformation after the main contractional phases of the orogeny. F3 folds might have resulted from accommodation during protracted E-W extension.

The Goldilocks contract: The synergistic benefits of combining structure and autonomy for persistence, creativity, and cooperation.

PubMed

Chou, Eileen Y; Halevy, Nir; Galinsky, Adam D; Murnighan, J Keith

2017-09-01

Contracts are commonly used to regulate a wide range of interactions and relationships. Yet relying on contracts as a mechanism of control often comes at a cost to motivation. Integrating theoretical perspectives from psychology, economics, and organizational theory, we explore this control-motivation dilemma inherent in contracts and present the Contract-Autonomy-Motivation-Performance-Structure (CAMPS) model, which highlights the synergistic benefits of combining structure and autonomy. The model proposes that subtle reductions in the specificity of a contract's language can boost autonomy, which increases intrinsic motivation and improves a range of desirable behaviors. Nine field and laboratory experiments found that less specific contracts increased task persistence, creativity, and cooperation, both immediately and longitudinally, because they boosted autonomy and intrinsic motivation. These positive effects, however, only occurred when contracts provided sufficient structure. Furthermore, the effects were limited to control-oriented clauses (i.e., legal clauses), and did not extend to coordination-oriented clauses (i.e., technical clauses). That is, there were synergistic benefits when a contract served as a scaffold that combined structure with general clauses. Overall, the current model and experiments identify a low-cost solution to the common problem of regulating social relationships: finding the right amount of contract specificity promotes desirable outcomes, including behaviors that are notoriously difficult to contract. The CAMPS model and the current set of empirical findings explain why, when, and how contracts can be used as an effective motivational tool. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Cretaceous–Cenozoic burial and exhumation history of the Chukchi shelf, offshore Arctic Alaska

USGS Publications Warehouse

Craddock, William H.; Houseknecht, David W.

2016-01-01

Apatite fission track (AFT) and vitrinite reflectance data from five exploration wells and three seafloor cores illuminate the thermal history of the underexplored United States Chukchi shelf. On the northeastern shelf, Triassic strata in the Chevron 1 Diamond well record apatite annealing followed by cooling, possibly during the Triassic to Middle Jurassic, which is a thermal history likely related to Canada Basin rifting. Jurassic strata exhumed in the hanging wall of the frontal Herald Arch thrust fault record a history of probable Late Jurassic to Early Cretaceous structural burial in the Chukotka fold and thrust belt, followed by rapid exhumation to near-surface temperatures at 104 ± 30 Ma. This history of contractional tectonism is in good agreement with inherited fission track ages in low-thermal-maturity, Cretaceous–Cenozoic strata in the Chukchi foreland, providing complementary evidence for the timing of exhumation and suggesting a source-to-sink relationship. In the central Chukchi foreland, inverse modeling of reset AFT samples from the Shell 1 Klondike and Shell 1 Crackerjack wells reveals several tens of degrees of cooling from maximum paleo-temperatures, with maximum heating permissible at any time from about 100 to 50 Ma, and cooling persisting to as recent as 30 Ma. Similar histories are compatible with partially reset AFT samples from other Chukchi wells (Shell 1 Popcorn, Shell 1 Burger, and Chevron 1 Diamond) and are probable in light of regional geologic evidence. Given geologic context provided by regional seismic reflection data, we interpret these inverse models to reveal a Late Cretaceous episode of cyclical burial and erosion across the central Chukchi shelf, possibly partially overprinted by Cenozoic cooling related to decreasing surface temperatures. Regionally, we interpret this kinematic history to be reflective of moderate, transpressional deformation of the Chukchi shelf during the final phases of contractional tectonism in the Chukotkan orogen (lasting until ∼70 Ma), followed by renewed subsidence of the Chukchi shelf in the latest Cretaceous and Cenozoic. This history maintained modest thermal maturities at the base of the Brookian sequence across the Chukchi shelf, because large sediment volumes bypassed to adjacent depocenters. Therefore, the Chukchi shelf appears to be an area with the potential for widespread preservation of petroleum systems in the oil window.

An AMS study of the Takidani pluton (Japan)

NASA Astrophysics Data System (ADS)

Hartung, Eva; Caricchi, Luca; Floess, David; Wallis, Simon; Harayama, Satoru

2016-04-01

Large plutonic bodies are typically constructed incrementally often by under-accretion of distinct successive magma pulses. Petrography and geochemistry of the Takidani Pluton (1.54 Ma ± 0.23 Ma) in the Northern Japanese Alps show that the chemical and textural variability observed at the roof of this intrusion is best explained by the segregation of residual melt from a crystallising magma body. We carried out a magnetic susceptibility survey (bulk susceptibility and anisotropy of magnetic susceptibility) to identify the structures associated with the emplacement and extraction of residual melts from a magmatic mush. Additionally, we determined shape preferred orientations (SPO) of amphibole at several locations within the Takidani pluton. From bottom to top of the intrusion, the bulk susceptibility is about constant in the main granodioritic part, decreases roofwards within the porphyritic unit, before increasing again within the marginal granodiorite close to the contact with the overlaying Hotaka Andesite. Such variability mimics the major and trace elements compositional variability measured in the whole rock samples. Magnetic foliations are observed at the western tectonic contact of the pluton potentially indicating overprint, while most other magnetic fabrics across the pluton are characterised by triaxial ellipsoids of magnetic susceptibility or magnetic lineations. Our preliminary data and the lack of internal contacts indicate that Takidani Pluton was likely emplaced as a series of successive magma pulses finally merging to produce a large connected magma body. While amphibole foliations may likely be the results of super-solidus tectonic overprint, anisotropy of magnetic susceptibility data may be related to post-emplacement melt segregation.

Using magma flow indicators to infer flow dynamics in sills

NASA Astrophysics Data System (ADS)

Hoyer, Lauren; Watkeys, Michael K.

2017-03-01

Fabrics from Anisotropy of Magnetic Susceptibility (AMS) analyses and Shape Preferred Orientation (SPO) of plagioclase are compared with field structures (such as bridge structures, intrusive steps and magma lobes) formed during magma intrusion in Jurassic sills. This is to constrain magma flow directions in the sills of the Karoo Igneous Province along the KwaZulu-Natal North Coast and to show how accurately certain structures predict a magma flow sense, thus improving the understanding of the Karoo sub-volcanic dynamics. The AMS fabrics are derived from magnetite grains and are well constrained, however the SPO results are commonly steeply inclined, poorly constrained and differ to the AMS fabrics. Both techniques resulted in asymmetrical fabrics. Successful relationships were established between the AMS fabric and the long axes of the magma flow indicators, implying adequate magma flow prediction. However, where numerous sill segments merge, either in the form of magma lobes or bridge structures, the coalescence process creates a new fabric between the segments preserving late-stage magma migration between the merged segments, overprinting the initial magma flow direction.

The family Rhabdoviridae: mono- and bipartite negative-sense RNA viruses with diverse genome organization and common evolutionary origins.

PubMed

Dietzgen, Ralf G; Kondo, Hideki; Goodin, Michael M; Kurath, Gael; Vasilakis, Nikos

2017-01-02

The family Rhabdoviridae consists of mostly enveloped, bullet-shaped or bacilliform viruses with a negative-sense, single-stranded RNA genome that infect vertebrates, invertebrates or plants. This ecological diversity is reflected by the diversity and complexity of their genomes. Five canonical structural protein genes are conserved in all rhabdoviruses, but may be overprinted, overlapped or interspersed with several novel and diverse accessory genes. This review gives an overview of the characteristics and diversity of rhabdoviruses, their taxonomic classification, replication mechanism, properties of classical rhabdoviruses such as rabies virus and rhabdoviruses with complex genomes, rhabdoviruses infecting aquatic species, and plant rhabdoviruses with both mono- and bipartite genomes. Copyright © 2016 Elsevier B.V. All rights reserved.

Multiphase Aqueous Alteration of the Nakhlite Northwest Africa 817

NASA Astrophysics Data System (ADS)

Lee, M. R.; Cohen, B. E.; Mark, D. F.; Boyce, A.

2017-07-01

The nakhlite meteorite Northwest Africa 817 has been aqueously altered on both Mars and Earth, producing clays, carbonates, sulphates and oxides. The challenge is to see through the terrestrial overprint to understand the martian signature.

Geochemistry, petrology, and palynology of the Pond Creek coal bed, northern Pike and southern Martin counties, Kentucky

USGS Publications Warehouse

Hower, J.C.; Ruppert, L.F.; Eble, C.F.; Clark, W.L.

2005-01-01

The geochemistry, petrology, and palynology of the Duckmantian-age Pond Creek coal bed were investigated in northern Pike and southern Martin counties, eastern Kentucky. The coal bed exhibits significant vertical variation in the investigated geochemical parameters, with many diagenetic overprints of the original geochemistry. Included in the range of geochemical signatures are the presence of elements, particularly TiO2 and Zr, suggesting the detrital influences at the time of deposition of a low-vitrinite durain; a high CaO zone with elevated B/Be, both suggesting marine influence, in a lithotype in the middle of the coal bed; and the postdepositional emplacement of pyrite in the uppermost lithotype. Individual lithotypes, each representing distinct depositional environments, all complicated to some degree by diagentic overprints, comprise the complex history of the coal bed. ?? 2004 Elsevier B.V. All rights reserved.

48 CFR 915.404-4-70 - DOE structured profit and fee system.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false DOE structured profit and fee system. 915.404-4-70 Section 915.404-4-70 Federal Acquisition Regulations System DEPARTMENT OF ENERGY CONTRACTING METHODS AND CONTRACT TYPES CONTRACTING BY NEGOTIATION Contract Pricing 915.404-4-70...

Exploring the market for third-party-owned residential photovoltaic systems: insights from lease and power-purchase agreement contract structures and costs in California

DOE PAGES

Davidson, Carolyn; Steinberg, Daniel; Margolis, Robert

2015-02-04

We report that over the past several years, third-party-ownership (TPO) structures for residential photovoltaic (PV) systems have become the predominant ownership model in the US residential market. Under a TPO contract, the PV system host typically makes payments to the third-party owner of the system. Anecdotal evidence suggests that the total TPO contract payments made by the customer can differ significantly from payments in which the system host directly purchases the system. Furthermore, payments can vary depending on TPO contract structure. To date, a paucity of data on TPO contracts has precluded studies evaluating trends in TPO contract cost. Thismore » study relies on a sample of 1113 contracts for residential PV systems installed in 2010–2012 under the California Solar Initiative to evaluate how the timing of payments under a TPO contract impacts the ultimate cost of the system to the customer. Furthermore, we evaluate how the total cost of TPO systems to customers has changed through time, and the degree to which contract costs have tracked trends in the installed costs of a PV system. We find that the structure of the contract and the timing of the payments have financial implications for the customer: (1) power-purchase contracts, on average, cost more than leases, (2) no-money-down contracts are more costly than prepaid contracts, assuming a customer's discount rate is lower than 17% and (3) contracts that include escalator clauses cost more, for both power-purchase agreements and leases, at most plausible discount rates. Additionally, all contract costs exhibit a wide range, and do not parallel trends in installed costs over time.« less

Exploring the market for third-party-owned residential photovoltaic systems: insights from lease and power-purchase agreement contract structures and costs in California

NASA Astrophysics Data System (ADS)

Davidson, Carolyn; Steinberg, Daniel; Margolis, Robert

2015-02-01

Over the past several years, third-party-ownership (TPO) structures for residential photovoltaic (PV) systems have become the predominant ownership model in the US residential market. Under a TPO contract, the PV system host typically makes payments to the third-party owner of the system. Anecdotal evidence suggests that the total TPO contract payments made by the customer can differ significantly from payments in which the system host directly purchases the system. Furthermore, payments can vary depending on TPO contract structure. To date, a paucity of data on TPO contracts has precluded studies evaluating trends in TPO contract cost. This study relies on a sample of 1113 contracts for residential PV systems installed in 2010-2012 under the California Solar Initiative to evaluate how the timing of payments under a TPO contract impacts the ultimate cost of the system to the customer. Furthermore, we evaluate how the total cost of TPO systems to customers has changed through time, and the degree to which contract costs have tracked trends in the installed costs of a PV system. We find that the structure of the contract and the timing of the payments have financial implications for the customer: (1) power-purchase contracts, on average, cost more than leases, (2) no-money-down contracts are more costly than prepaid contracts, assuming a customer’s discount rate is lower than 17% and (3) contracts that include escalator clauses cost more, for both power-purchase agreements and leases, at most plausible discount rates. In addition, all contract costs exhibit a wide range, and do not parallel trends in installed costs over time.

Exploring the market for third-party-owned residential photovoltaic systems: insights from lease and power-purchase agreement contract structures and costs in California

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

Davidson, Carolyn; Steinberg, Daniel; Margolis, Robert

We report that over the past several years, third-party-ownership (TPO) structures for residential photovoltaic (PV) systems have become the predominant ownership model in the US residential market. Under a TPO contract, the PV system host typically makes payments to the third-party owner of the system. Anecdotal evidence suggests that the total TPO contract payments made by the customer can differ significantly from payments in which the system host directly purchases the system. Furthermore, payments can vary depending on TPO contract structure. To date, a paucity of data on TPO contracts has precluded studies evaluating trends in TPO contract cost. Thismore » study relies on a sample of 1113 contracts for residential PV systems installed in 2010–2012 under the California Solar Initiative to evaluate how the timing of payments under a TPO contract impacts the ultimate cost of the system to the customer. Furthermore, we evaluate how the total cost of TPO systems to customers has changed through time, and the degree to which contract costs have tracked trends in the installed costs of a PV system. We find that the structure of the contract and the timing of the payments have financial implications for the customer: (1) power-purchase contracts, on average, cost more than leases, (2) no-money-down contracts are more costly than prepaid contracts, assuming a customer's discount rate is lower than 17% and (3) contracts that include escalator clauses cost more, for both power-purchase agreements and leases, at most plausible discount rates. Additionally, all contract costs exhibit a wide range, and do not parallel trends in installed costs over time.« less

Opportunity at Concepci?n Crater, Seen from Orbit

NASA Image and Video Library

2010-03-24

This image, acquired by NASA Mars Reconnaissance Orbiter, shows the rover Opportunity perched on the edge of Concepci?n crater, a fresh crater with dark rays that clearly overprint the north-trending, wind-shaped ripples, in Meridiani Planum.

3D visualization of deformation structures and potential fluid pathways at the Grimsel Test Site

NASA Astrophysics Data System (ADS)

Schneeberger, Raphael; Kober, Florian; Berger, Alfons; Spillmann, Thomas; Herwegh, Marco

2015-04-01

Knowledge on the ability of fluids to infiltrate subsurface rocks is of major importance for underground constructions, geothermal or radioactive waste disposal projects. In this study, we focus on the characterization of water infiltration pathways, their 3D geometries and origins. Based on surface and subsurface mapping in combination with drill core data, we developed by the use of MoveTM (Midland Valley Exploration Ltd.) a 3D structural model of the Grimsel Test Site (GTS). GTS is an underground laboratory operated by NAGRA, the Swiss organisation responsible for the management of nuclear waste. It is located within a suite of post-Variscan magmatic bodies comprising former granitic and granodioritic melts, which are dissected by mafic and aplitic dikes. During Alpine orogeny, the suite was tectonically overprinted within two stages of ductile deformation (Wehrens et al., in prep.) followed by brittle overprint of some of the shear zones during the retrograde exhumation history. It is this brittle deformation, which controls today's water infiltration network. However, the associated fractures, cataclasites and fault gouges are controlled themselves by aforementioned pre-existing mechanical discontinuities, whose origin ranges back as far as to the magmatic stage. For example, two sets of vertically oriented mafic dikes (E-W and NW-SE striking) and compositional heterogeneities induced by magmatic segregation processes in the plutonic host rocks served as nucleation sites for Alpine strain localization. Subsequently, NE-SW, E-W and NW-SE striking ductile shear zones were formed, in combination with high temperature fracturing while dissecting the host rocks in a complex 3D pattern (Wehrens et al, in prep.). Whether the ductile shear zones have been subjected to brittle reactivation and can serve as infiltration pathways or not, depends strongly on their orientations with respect to the principal stress field. Especially where deformation structures intersect each other, water flow is high. Our 3D structural model allows the recognition of such intersections in 3D space and the prediction of their spatial extent. The structural model developed with the introduction of the locally known hydraulic permeabilities and in combination with the results of on-going hydrochemical investigations will allow to estimate the location of the recently active water pathways. References Wehrens, P., Baumberger, R., Berger, A., & Herwegh, M. (in prep.). How is strain localized in a mid-crustal basement section? Spatial distribution of deformation in the Aar massif (Switzerland).

Eocene and Miocene extension, meteoric fluid infiltration, and core complex formation in the Great Basin (Raft River Mountains, Utah)

USGS Publications Warehouse

Methner, Katharina; Mulch, Andreas; Teyssier, Christian; Wells, Michael L.; Cosca, Michael A.; Gottardi, Raphael; Gebelin, Aude; Chamberlain, C. Page

2015-01-01

Metamorphic core complexes (MCCs) in the North American Cordillera reflect the effects of lithospheric extension and contribute to crustal adjustments both during and after a protracted subduction history along the Pacific plate margin. While the Miocene-to-recent history of most MCCs in the Great Basin, including the Raft River-Albion-Grouse Creek MCC, is well documented, early Cenozoic tectonic fabrics are commonly severely overprinted. We present stable isotope, geochronological (40Ar/39Ar), and microstructural data from the Raft River detachment shear zone. Hydrogen isotope ratios of syntectonic white mica (δ2Hms) from mylonitic quartzite within the shear zone are very low (−90‰ to −154‰, Vienna SMOW) and result from multiphase synkinematic interaction with surface-derived fluids. 40Ar/39Ar geochronology reveals Eocene (re)crystallization of white mica with δ2Hms ≥ −154‰ in quartzite mylonite of the western segment of the detachment system. These δ2Hms values are distinctively lower than in localities farther east (δ2Hms ≥ −125‰), where 40Ar/39Ar geochronological data indicate Miocene (18–15 Ma) extensional shearing and mylonitic fabric formation. These data indicate that very low δ2H surface-derived fluids penetrated the brittle-ductile transition as early as the mid-Eocene during a first phase of exhumation along a detachment rooted to the east. In the eastern part of the core complex, prominent top-to-the-east ductile shearing, mid-Miocene 40Ar/39Ar ages, and higher δ2H values of recrystallized white mica, indicate Miocene structural and isotopic overprinting of Eocene fabrics.

Microstructural, textural and thermal evolution of an exhumed strike-slip fault and insights into localization and rheological transition

NASA Astrophysics Data System (ADS)

Cao, Shuyun; Neubauer, Franz; Liu, Junlai; Bernroider, Manfred; Genser, Johann

2016-04-01

The presence of deep exhumed crustal rocks with a dominant but contrasting mineralogy results in shear concentration in the rheological weakest layer, which exhibits contrasting patterns of fabrics and thermal conditions during their formation. We tested a combination of methodologies including microstructural and textural investigations, geochronology and geothermometry on deformed rocks from exhumed strike-slip fault, Ailao Shan-Red River, SE, Asian. Results indicate that the exhumed deep crustal rocks since late Oligocene (ca. 28 Ma) to Pliocene (ca. 4 Ma) typically involve dynamic microstructural, textural and thermal evolution processes, which typically record a progressive deformation and syn-kinematic reactions from ductile to semi-ductile and brittle behavior during exhumation. This transformation also resulted in dramatic strength reduction that promoted strain localization along the strike-slip and transtensional faults. Detailed analysis has revealed the co-existence of microfabrics ranging from high-temperatures (granulite facies conditions) to overprinting low-temperatures (lower greenschist facies conditions). The high-temperature microstructures and textures are in part or entirely altered by subsequent, overprinting low-temperature shearing. In quartz-rich rocks, quartz was deformed in the dislocation creep regime and records transition of microfabrics and slip systems during decreasing temperature, which lasted until retrogression related to final exhumation. As a result, grain-size reduction associated by fluids circulating within the strike-slip fault zone at brittle-ductile transition leads to rock softening, which resulted in strain localization, weak rock rheology and the overall hot thermal structure of the crust. Decompression occurred during shearing and as a result of tectonic exhumation. All these results demonstrate that the ductile to ductile-brittle transition involves a combination of different deformation mechanisms, rheological transition features and feedbacks between deformation, decreasing temperature and fluids.

48 CFR 3016.170 - Contracts with Lead System Integrators.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 48 Federal Acquisition Regulations System 7 2012-10-01 2012-10-01 false Contracts with Lead System... Selecting Contract Types 3016.170 Contracts with Lead System Integrators. The contracting officer should... consulted to determine the appropriate contract type and fee structure for use in varied contracts with lead...

48 CFR 3016.170 - Contracts with Lead System Integrators.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 48 Federal Acquisition Regulations System 7 2013-10-01 2012-10-01 true Contracts with Lead System... Selecting Contract Types 3016.170 Contracts with Lead System Integrators. The contracting officer should... consulted to determine the appropriate contract type and fee structure for use in varied contracts with lead...

48 CFR 3016.170 - Contracts with Lead System Integrators.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 48 Federal Acquisition Regulations System 7 2014-10-01 2014-10-01 false Contracts with Lead System... Selecting Contract Types 3016.170 Contracts with Lead System Integrators. The contracting officer should... consulted to determine the appropriate contract type and fee structure for use in varied contracts with lead...

48 CFR 3016.170 - Contracts with Lead System Integrators.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 48 Federal Acquisition Regulations System 7 2011-10-01 2011-10-01 false Contracts with Lead System... Selecting Contract Types 3016.170 Contracts with Lead System Integrators. The contracting officer should... consulted to determine the appropriate contract type and fee structure for use in varied contracts with lead...

48 CFR 3016.170 - Contracts with Lead System Integrators.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 7 2010-10-01 2010-10-01 false Contracts with Lead System... Selecting Contract Types 3016.170 Contracts with Lead System Integrators. The contracting officer should... consulted to determine the appropriate contract type and fee structure for use in varied contracts with lead...

Defense Health Care: Evaluation of TRICARE Pharmacy Services Contract Structure is Warranted

DTIC Science & Technology

2013-09-01

involves providing coordinated health care interventions and communications to patients who have chronic conditions, such as diabetes or asthma ...DEFENSE HEALTH CARE Evaluation of TRICARE Pharmacy Services Contract Structure Is Warranted Report to the...COVERED 00-00-2013 to 00-00-2013 4. TITLE AND SUBTITLE Defense Health Care : Evaluation of TRICARE Pharmacy Services Contract Structure Is

Analysis of the 918th Contracting Battalion and 410th Contracting Support Brigade Utilizing the Contract Management Maturity Model

DTIC Science & Technology

2015-12-01

organizational structure of Army contracting and the changes to that organization under the MICC 2025 plan. We then describe the organizations where we... organizational change . Portal: Libraries and the Academy, 4(3), 345–361. McFall, T. (2015). 918th CBN/MICC-FC organizational overview [PowerPoint slides...Installation Contracting Command (MICC) are undergoing a significant change in structure known as MICC 2025. In order to gauge the effectiveness of this

Directional Cluster Analysis on a Sphere: Retrieval of Archean Magnetic Directions from Data with High Dispersion

NASA Astrophysics Data System (ADS)

Bono, R. K.; Dare, M. S.; Tarduno, J. A.; Cottrell, R. D.

2016-12-01

Magnetic directions from coarse clastic rocks are typically highly scattered, to the point that the null hypothesis that they are drawn from a random distribution, using the iconic test of Watson (1956), cannot be rejected at a high confidence level (e.g. 95%). Here, we use an alternative approach of searching for directional clusters on a sphere. When applied to a new data set of directions from quartzites from the Jack Hills of Western Australia, we find evidence for distinct and meaningful magnetic directions at low (200 to 300 degrees C) and intermediate ( 350 to 450 degrees C) unblocking temperatures, whereas the test of Watson (1956) fails to draw a distinction from random distributions for the ensemble of directions at these unblocking temperature ranges. The robustness of the directional groups identified by the cluster analysis is confirmed by non-parametric resampling tests. The lowest unblocking temperature directional mode appears related to the present day field, perhaps contaminated by viscous magnetizations. The intermediate temperature magnetization matches an overprint recorded by the secondary mineral fuchsite (Cottrell et al., 2016) acquired at ca. 2.65 Ga. These data thus indicate that the Jack Hills carry an overprint at intermediate unblocking temperatures of Archean age. We find no evidence for a 1 Ga remagnetization. In general, the application of cluster analysis on a sphere, with directions confirmed by nonparametric tests, represents a new approach that should be applied when evaluating data with high dispersion, such as those that typically come from weak coarse-grained clastic sedimentary rocks, and/or rocks that have seen several tectonic events that could have imparted multiple magnetic overprints.

40Ar/39Ar thermochronology of mesoproterozoic metamorphism in the Colorado Front Range

USGS Publications Warehouse

Shaw, C.A.; Snee, L.W.; Selverstone, J.; Reed, J.C.

1999-01-01

A low-pressure metamorphic episode in the Colorado Front Range has been identified by the presence of staurolite, andalusite, cordierite, and garnet porphyroblasts overprinting earlier assemblages. The overprinting assemblages and reaction textures are most consistent with porphyroblast growth on a prograde metamorphic path with peak temperatures exceeding ~525??C. Twenty-eight 40Ar/39Ar dates on hornblende, muscovite, biotite, and microcline were used to infer the age and thermal conditions of metamorphism. Muscovite and biotite 40Ar/39Ar ages fall mainly in the interval 1400-1340 Ma, consistent with cooling through the closure temperature interval of micas (~400??-300??C) after about 1400 Ma. In contrast, hornblende apparent ages (T(c)~500??-550??C) between 1600 and 1390 Ma reflect variable retention of radiogenic argon. Forward modeling of argon diffusion shows that the distribution of hornblende and mica ages is consistent with the partial resetting of argon systematics ca. 1400 Ma by a thermal pulse reaching maximum temperatures around 550??C and decaying within <20 m.yr. These temperatures match the conditions inferred from the overprinting assemblage; thus, muscovite and biotite ages are interpreted to date the cooling phase of this metamorphic event. This late metamorphism is broadly coeval with the intrusion of ca. 1400-Ma granitic plutons in the study area and throughout the southwestern United States. However, thermal effects are observed far from pluton margins, suggesting pervasive, regional crustal heating rather than restricted contact metamorphism. Our results suggest that ca. 1400-Ma metamorphism and plutonism are manifestations of a regional thermal episode that both partially melted the lower crust and pervasively metamorphosed middle crustal rocks.

Mesoarchean melting and Neoarchean to Paleoproterozoic metasomatism during the formation of the cratonic mantle keel beneath West Greenland

NASA Astrophysics Data System (ADS)

van Acken, D.; Luguet, A.; Pearson, D. G.; Nowell, G. M.; Fonseca, R. O. C.; Nagel, T. J.; Schulz, T.

2017-04-01

Highly siderophile element (HSE) concentration and 187Os/188Os isotopic heterogeneity has been observed on various scales in the Earth's mantle. Interaction of residual mantle peridotite with infiltrating melts has been suggested to overprint primary bulk rock HSE signatures originating from partial melting, contributing to the heterogeneity seen in the global peridotite database. Here we present a detailed study of harzburgitic xenolith 474527 from the Kangerlussuaq suite, West Greenland, coupling the Re-Os isotope geochemistry with petrography of both base metal sulfides (BMS) and silicates to assess the impact of overprint induced by melt-rock reaction on the Re-Os isotope system. Garnet harzburgite sample 474527 shows considerable heterogeneity in the composition of its major phases, most notably olivine and Cr-rich garnet, suggesting formation through multiple stages of partial melting and subsequent metasomatic events. The major BMS phases show a fairly homogeneous pentlandite-rich composition typical for BMS formed via metasomatic reaction, whereas the 187Os/188Os compositions determined for 17 of these BMS are extremely heterogeneous ranging between 0.1037 and 0.1981. Analyses by LA-ICP-MS reveal at least two populations of BMS grains characterized by contrasting HSE patterns. One type of pattern is strongly enriched in the more compatible HSE Os, Ir, and Ru over the typically incompatible Pt, Pd, and Re, while the other type shows moderate enrichment of the more incompatible HSE and has overall lower compatible HSE/incompatible HSE composition. The small-scale heterogeneity observed in these BMS highlights the need for caution when utilizing the Re-Os system to date mantle events, as even depleted harzburgite samples such as 474527 are likely to have experienced a complex history of metasomatic overprinting, with uncertain effects on the HSE.

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.

Evidence for a composite organic-inorganic fabric of belemnite rostra: implication for palaeoceanography

NASA Astrophysics Data System (ADS)

Hoffmann, Rene; Richter, Detlev K.; Neuser, Rolf D.; Jöns, Niels; Linzmeier, Benjamin J.; Lemanis, Robert E.; Fusseis, Florian; Xiao, Xianghui; Immenhauser, Adrian

2017-04-01

Carbonate skeletons of fossil marine organisms are widely used to reconstruct palaeoenvironments. Specifically, the geochemistry of Jurassic and Cretaceous belemnite rostra is commonly applied to reconstruct palaeoseawater properties. This is due to the assumption that belemnites, as member of the mollusc group, precipitated their rostra in equilibrium with the palaeoenvironment and secondly it was assumed that rostra represent primary dense low Mg calcite structures and relatively stable against diagenetic overprinting. More recently an increasing number of published data, show significant scatter in geochemical data (e.g., d18O, d13C, element/Ca ratio) when comparing belemnite rostra from the same stratigraphic level or within a single belemnite rostrum. This scatter is not explained by differential diagenetic overprint alone but also by vertical and horizontal migration patterns, seasonality, or changes in salinity. In order to test for an ultrastructural-related explanation for the observed scatter we employed a wide range of state-of-the-art analytical tools, e.g., cathodoluminescence, fluorescence- and confocal laser fluorescence microscopy, scanning electron microscopy equipped with a backscatter detector, electron microprobe analysis, electron backscatter diffraction imaging to thin sections and ultra-thin sections of well-preserved specimens. We found petrographic evidence that the primary, i.e. biogenic, ultrastructure of rostra of Megateuthis (Middle Jurassic) and Belemnitella and Gonioteuthis (Late Cretaceous) was not a dense calcite structure, but contained primary porosity. The biogenic ultrastructure consists of a filigree framework of tetrahedrons of variable size with branches forming a honeycomb-like network. Data presented here suggest that these rostra yielded as much as 50 to 90% primary pore space. We propose that the pore space was originally filled with body fluid and/or organic compounds during the life time of these organisms in analogy with modern cephalopods. Intra-rostral porosity was occluded post mortem by earliest diagenetic isopachous calcite cements of a non-biogenic origin. These may have been precipitated due to increased alkalinity related to the decay of organic matter. If this holds true, then the resulting fabric represents a composite biogenic/abiogenic structure precipitated at different times and depths in the water column. We suggest that these findings have significance for those using belemnite rostra as archives of their palaeoenvironment, for the reconstruction of belemnite palaeoecology, and for the functional interpretation of belemnite rostra.

Gold and palladium minerals (including empirical PdCuBiSe3) from the former Roter Bär mine, St. Andreasberg, Harz Mountains, Germany: a result of low-temperature, oxidising fluid overprint

NASA Astrophysics Data System (ADS)

Cabral, Alexandre Raphael; Ließmann, Wilfried; Lehmann, Bernd

2015-10-01

At Roter Bär, a former underground mine in the polymetallic deposits of St. Andreasberg in the middle-Harz vein district, Germany, native gold and palladium minerals occur very locally in clausthalite-hematite pockets of few millimetres across in carbonate veinlets. The native gold is a Au-Ag intermetallic compound and the palladium minerals are characterised as mertieite-II [Pd8(Sb,As)3] and empirical PdCuBiSe3 with some S. The latter coexists with bohdanowiczite (AgBiSe2), a mineral that is stable below 120 °C. The geological setting of Roter Bär, underneath a post-Variscan unconformity, and its hematite-selenide-gold association suggest that oxidising hydrothermal brines of low temperature were instrumental to the Au-Pd mineralisation. The Roter Bär Au-Pd mineralisation can be explained by Permo-Triassic, red-bed-derived brines in the context of post-Variscan, unconformity-related fluid overprint.

Back-thrusting in Lesser Himalaya: Evidences from magnetic fabric studies in parts of Almora crystalline zone, Kumaun Lesser Himalaya

NASA Astrophysics Data System (ADS)

Agarwal, Amar; Agarwal, K. K.; Bali, R.; Prakash, Chandra; Joshi, Gaurav

2016-06-01

The present study aims to understand evolution of the Lesser Himalaya, which consists of (meta) sedimentary and crystalline rocks. Field studies, microscopic and rock magnetic investigations have been carried out on the rocks near the South Almora Thrust (SAT) and the North Almora Thrust (NAT), which separates the Almora Crystalline Zone (ACZ) from the Lesser Himalayan sequences (LHS). The results show that along the South Almora Thrust, the deformation is persistent; however, near the NAT deformation pattern is complex and implies overprinting of original shear sense by a younger deformational event. We attribute this overprinting to late stage back-thrusting along NAT, active after the emplacement of ACZ. During this late stage back-thrusting, rocks of the ACZ and LHS were coupled. Back-thrusts originated below the Lesser Himalayan rocks, probably from the Main Boundary Thrust, and propagated across the sedimentary and crystalline rocks. This study provides new results from multiple investigations, and enhances our understanding of the evolution of the ACZ.

Finding the 'sweet spot' in value-based contracts.

PubMed

Eggbeer, Bill; Sears, Kevin; Homer, Ken

2015-08-01

Health systems pursing value-based contracts should address six important considerations: The definition of value. Contracting goals. Cost of implementation. Risk exposure. Contract structure and design. Essential contractual protections.

48 CFR 36.102 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-10-01

... CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS General 36.102 Definitions. As used in this part— Contract is intended to refer to a contract for construction or a contract for architect-engineer services..., structural, electrical, mechanical, and fire protection), producing the technical specifications and drawings...

48 CFR 36.102 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-10-01

... CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS General 36.102 Definitions. As used in this part— Contract is intended to refer to a contract for construction or a contract for architect-engineer services..., structural, electrical, mechanical, and fire protection), producing the technical specifications and drawings...

48 CFR 36.102 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-10-01

... CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS General 36.102 Definitions. As used in this part— Contract is intended to refer to a contract for construction or a contract for architect-engineer services..., structural, electrical, mechanical, and fire protection), producing the technical specifications and drawings...

48 CFR 36.102 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-10-01

... CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS General 36.102 Definitions. As used in this part— Contract is intended to refer to a contract for construction or a contract for architect-engineer services..., structural, electrical, mechanical, and fire protection), producing the technical specifications and drawings...

48 CFR 36.102 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-10-01

... CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS General 36.102 Definitions. As used in this part— Contract is intended to refer to a contract for construction or a contract for architect-engineer services..., structural, electrical, mechanical, and fire protection), producing the technical specifications and drawings...

Marble-hosted ruby deposits of the Morogoro Region, Tanzania

NASA Astrophysics Data System (ADS)

Balmer, Walter A.; Hauzenberger, Christoph A.; Fritz, Harald; Sutthirat, Chakkaphan

2017-10-01

The ruby deposits of the Uluguru and Mahenge Mts, Morogoro Region, are related to marbles which represent the cover sequence of the Eastern Granulites in Tanzania. In both localities the cover sequences define a tectonic unit which is present as a nappe structure thrusted onto the gneissic basement in a north-western direction. Based on structural geological observations the ruby deposits are bound to mica-rich boudins in fold hinges where fluids interacted with the marble-host rock in zones of higher permeability. Petrographic observations revealed that the Uluguru Mts deposits occur within calcite-dominated marbles whereas deposits in the Mahenge Mts are found in dolomite-dominated marbles. The mineral assemblage describing the marble-hosted ruby deposit in the Uluguru Mts is characterised by corundum-dolomite-phlogopite ± spinel, calcite, pargasite, scapolite, plagioclase, margarite, chlorite, tourmaline whereas the assemblage corundum-calcite-plagioclase-phlogopite ± dolomite, pargasite, sapphirine, titanite, tourmaline is present in samples from the Mahenge Mts. Although slightly different in mineral assemblage it was possible to draw a similar ruby formation history for both localities. Two ruby forming events were distinguished by textural differences, which could also be modeled by thermodynamic T-XCO2 calculations using non-ideal mixing models of essential minerals. A first formation of ruby appears to have taken place during the prograde path (M1) either by the breakdown of diaspore which was present in the original sedimentary precursor rock or by the breakdown of margarite to corundum and plagioclase. The conditions for M1 metamorphism was estimated at ∼750 °C at 10 kbar, which represents granulite facies conditions. A change in fluid composition towards a CO2 dominated fluid triggered a second ruby generation to form. Subsequently, the examined units underwent a late greenschist facies overprint. In the framework of the East African Orogen we assume that the prograde ruby formation occurred at the commonly observed metamorphic event around 620 Ma. At the peak or during beginning of retrogression the fluid composition changed triggering a second ruby generation. The late stage greenschist facies overprint could have occurred at the waning stage of this metamorphic episode which is in the range of ∼580 Ma.

Tectonic evolution of kid metamorphic complex and the recognition of Najd fault system in South East Sinai, Egypt

NASA Astrophysics Data System (ADS)

Sultan, Yasser M.; El-Shafei, Mohamed K.; Arnous, Mohamed O.

2017-03-01

A low-to medium-grade metamorphic belt of a volcano-sedimentary succession occurs in the eastern side of South Sinai as a part of the northernmost extension of the Arabian-Nubian Shield in Egypt. The belt is known as the Kid metamorphic complex. It is considered as one of the major belt among the other exposed metamorphic belts in South Sinai. Here, we detect and investigate the signature of the Najd Fault system in South Sinai based on detailed structural analysis in field and digital image processing. The enhanced satellite image and the geo-spatial distributions confirm that the Kid belt is essentially composed of nine Precambrian units. Field relations and geometrical analysis of the measured structural data revealed that the study area underwent four successive deformational phases (D1-D4). D1 is an upright tight to isoclinal large-scale folds that caused few F1 small-scale folds and a steeply dipping S1 axial plane foliation. The second deformational event D2 produced dominant of sub-horizontal S2 foliation planes accompanied with recumbent isoclinal folds and NW-SE trending L2 lineations. The main sense during D2 was top-to-the-NW with local reversals to the SE. The third folding generations F3 is recorded as axial plane S3-surfaces and is characterized by open concentric folding that overprinting both F1 and F2 folds and has a flexural-slip mechanism. F3 fold hinges plunge to the west-northwest or east-southeast indicate north-northeast-south-southwest shortening during D3. The fourth deformational event D4 is characterized by NE plunging open concentric folding overprint the pre-existing fold generations and formed under flexural slip mechanism reflecting coaxial deformation and indicating change in the stress regime as a result of the change in shortening from NE-SW to NW-SE. This phase is probably accompanied with the final assembly of east and west Gondwana. The dextral NW-SE shear zone that bounded the southwestern portion of the metamorphic belt is probably related to reactivation of the Najd fault system during Oligo-Miocene in South Sinai.

47 CFR 27.56 - Antenna structures; air navigation safety.

Code of Federal Regulations, 2010 CFR

2010-10-01

..., WTB, 1270 Fairfield Road, Gettysburg, PA 17325. (b) Maintenance contracts. Antenna structure owners... contracts with other entities to monitor and carry out necessary maintenance of antenna structures. Antenna... make such contractual arrangements continue to be responsible for the maintenance of antenna structures...

48 CFR 1515.404-475 - Cost realism.

Code of Federal Regulations, 2010 CFR

2010-10-01

... METHODS AND CONTRACT TYPES CONTRACTING BY NEGOTIATION Contract Pricing 1515.404-475 Cost realism. The EPA structured approach is not required when the contracting officer is evaluating cost realism in a competitive...

Evaluating links between deformation, topography and surface temperature at volcanic domes: Results from a multi-sensor study at Volcán de Colima, Mexico

NASA Astrophysics Data System (ADS)

Salzer, Jacqueline T.; Milillo, Pietro; Varley, Nick; Perissin, Daniele; Pantaleo, Michele; Walter, Thomas R.

2017-12-01

Dome building activity is common at many volcanoes and due to the gravitational instability, a dome represents one of the most hazardous volcanic phenomena. Shallow volcanic processes as well as rheological and structural changes of the dome affecting the fluid transport have been linked to transitions in eruptive activity. Also, hydrothermal alteration may affect the structural integrity of the dome, increasing the potential for collapse. However, mapping the deformation and details of fluid escape at the summit of steep sloped volcanoes and integrating these with other types of data is challenging due to difficult access and poor coverage. Here we present for the first time the near-vertical and near-horizontal surface deformation field of a quiescent summit dome and the relationships with degassing and topographic patterns. Our results are derived from high resolution satellite radar interferometry (InSAR) time series based on a year of TerraSAR-X SpotLight acquisitions and Structure from Motion (SfM) processing of overflight infrared data at Volcán de Colima, Mexico. The identified deformation is dominated by localized heterogeneous subsidence of the summit dome exceeding rates of 15 cm/yr, and strongly decreasing over the year 2012, up to the renewal of explosive and extrusive activity in early 2013. We tentatively attribute the deformation to the degassing, cooling and contraction of the dome and shallow conduit material. We also find that the results strongly differ depending on the chosen InSAR time series method, which potentially overprints the true physical complexities of small scale, shallow deformation processes. The combined interpretation of the deformation and infrared data reveals a complex spatial relationship between the degassing pathways and the deformation. While we observe no deformation across the crater rim fumaroles, discontinuities in the deformation field are more commonly observed around the dome rim fumaroles and occasionally on the dome upper surface. We propose that the deformation pattern is also linked to processes controlling the fumarole formation and distribution (topography, permeability and volcanic activity), and the lack of direct relationships may be explained by how the influence of these processes varies across the volcanic summit. The presented work provides a new approach for safely monitoring the activity and stability of internal dome structures, as well as for constraining and validating models of dome degassing pathways and densification processes.

Combined Lu-Hf and Sm-Nd geochronology of the Mariánské Lázně Complex: New constraints on the timing of eclogite- and granulite-facies metamorphism

NASA Astrophysics Data System (ADS)

Collett, Stephen; Štípská, Pavla; Schulmann, Karel; Peřestý, Vít; Soldner, Jeremie; Anczkiewicz, Robert; Lexa, Ondrej; Kylander-Clark, Andrew

2018-04-01

Lu-Hf and Sm-Nd garnet-whole rock geochronology combined with petrographic observations, minero-chemical variations, thermodynamic modelling and structural data was used to constrain the P-T-t-d evolution of eclogites from the Mariánské Lázně Complex (Bohemian Massif). Boudins of mostly isotropic eclogite with relict steep eclogite-facies fabric are affected by steep migmatitic foliation, which is followed on a regional scale by the development of almost pervasive, predominantly SE-dipping, extensional foliation. The structural succession shows continuous transition from eclogite to garnetiferous migmatitic amphibolite and to amphibolite migmatite. A least retrogressed sample of eclogite shows clusters of fine-grained inclusion-poor garnet, omphacite relicts surrounded by a fine-grained clinopyroxene-plagioclase symplectite with minor amphibole, biotite-plagioclase intergrowths after white mica, kyanite with plagioclase-spinel coronas and accessory rutile. Rare potassic white mica occurs as inclusions in omphacite. A more retrogressed eclogite, with no omphacite or kyanite relicts, contains inclusion-poor garnet surrounded by amphibole-plagioclase corona in a matrix dominated by plagioclase-amphibole symplectite with minor clinopyroxene. In places, the symplectite is overgrown by coarse-grained amphibole. Peak P-T conditions, inferred from combined conventional thermobarometry and phase-equilibria modelling and based on inclusions of white mica (up to 3.33 Si p.f.u.), matrix omphacite (Jd33-36) and garnet core (Alm33-38Prp38-42Grs22-25Sps1) compositions are 25 kbar at 650-750 °C. A HT overprint occurred at 14-18 kbar and >800 °C based on coexisting clinopyroxene (Jd18-24), plagioclase (An18-35), and amphibole (Na(B) <0.20; Al(C) = 0.60-1.15) in symplectite after original omphacite and phase-equilibria modelling of garnet mantle compositions. Lu-Hf and Sm-Nd garnet geochronology has been applied to both samples, an older age (c. 390 Ma) obtained by the Lu-Hf method is interpreted as the timing of HP metamorphism, while c. 15 Ma younger ages were obtained by the Sm-Nd method. As temperatures for the HT overprint exceed the empirically and experimentally determined closure temperature of the Sm-Nd system the Sm-Nd ages are interpreted to date cooling following the HT overprint. Combined together, contrasting eclogite and amphibolite-facies migmatite fabrics, the mineral textures, calculated P-T conditions, and distinct Lu-Hf and Sm-Nd ages, provide a complete P-T-t-D path characterised by rapid ( 15 Ma) transition from HP subduction, crustal thickening to extensional HT shearing. This unconventional exhumation path does not fit to models of monocyclic exhumation in a subduction channel proposed for the Münchberg and ZEV Devonian HP units to the west. In contrast, the post-peak extensional low angle shearing shortly after subduction and collision resembles more the geodynamic model typical for the Iberian subduction system both in time scales and sequence of tectonic events.

48 CFR 215.404-4 - Profit.

Code of Federal Regulations, 2010 CFR

2010-10-01

... DEFENSE CONTRACTING METHODS AND CONTRACT TYPES CONTRACTING BY NEGOTIATION Contract Pricing 215.404-4... prenegotiation profit or fee objective on any negotiated contract action when cost or pricing data is obtained... analysis when assessing cost realism in competitive acquisitions. (2) When using a structured approach, the...

Extraction of sandy bedforms features through geodesic morphometry

NASA Astrophysics Data System (ADS)

Debese, Nathalie; Jacq, Jean-José; Garlan, Thierry

2016-09-01

State-of-art echosounders reveal fine-scale details of mobile sandy bedforms, which are commonly found on continental shelfs. At present, their dynamics are still far from being completely understood. These bedforms are a serious threat to navigation security, anthropic structures and activities, placing emphasis on research breakthroughs. Bedform geometries and their dynamics are closely linked; therefore, one approach is to develop semi-automatic tools aiming at extracting their structural features from bathymetric datasets. Current approaches mimic manual processes or rely on morphological simplification of bedforms. The 1D and 2D approaches cannot address the wide ranges of both types and complexities of bedforms. In contrast, this work attempts to follow a 3D global semi-automatic approach based on a bathymetric TIN. The currently extracted primitives are the salient ridge and valley lines of the sand structures, i.e., waves and mega-ripples. The main difficulty is eliminating the ripples that are found to heavily overprint any observations. To this end, an anisotropic filter that is able to discard these structures while still enhancing the wave ridges is proposed. The second part of the work addresses the semi-automatic interactive extraction and 3D augmented display of the main lines structures. The proposed protocol also allows geoscientists to interactively insert topological constraints.

Contrasting magmatic structures between small plutons and batholiths emplaced at shallow crustal level (Sierras de Córdoba, Argentina)

NASA Astrophysics Data System (ADS)

Pinotti, Lucio P.; D'Eramo, Fernando J.; Weinberg, Roberto F.; Demartis, Manuel; Tubía, José María; Coniglio, Jorge E.; Radice, Stefania; Maffini, M. Natalia; Aragón, Eugenio

2016-11-01

Processes like injection, magma flow and differentiation and influence of the regional strain field are here described and contrasted to shed light on their role in the formation of small plutons and large batholiths their magmatic structures. The final geometric and compositional arrangement of magma bodies are a complex record of their construction and internal flow history. Magma injection, flow and differentiation, as well as regional stresses, all control the internal nature of magma bodies. Large magma bodies emplaced at shallow crustal levels result from the intrusion of multiple magma batches that interact in a variety of ways, depending on internal and external dynamics, and where the early magmatic, growth-related structures are commonly overprinted by subsequent history. In contrast, small plutons emplaced in the brittle-ductile transition more likely preserve growth-related structures, having a relatively simple cooling history and limited internal magma flow. Outcrop-scale magmatic structures in both cases record a rich set of complementary information that can help elucidate their evolution. Large and small granitic bodies of the Sierra Pampeanas preserve excellent exposures of magmatic structures that formed as magmas stepped through different rheological states during pluton growth and solidification. These structures reveal not only the flow pattern inside magma chambers, but also the rheological evolution of magmas in response to temperature evolution.

Some Analogies of the Banach Contraction Principle in Fuzzy Modular Spaces

PubMed Central

Wongkum, Kittipong; Chaipunya, Parin; Kumam, Poom

2013-01-01

We established some theorems under the aim of deriving variants of the Banach contraction principle, using the classes of inner contractions and outer contractions, on the structure of fuzzy modular spaces. PMID:23766681

A palaeomagnetic study of the lower part of the Palaeoproterozoic Waterberg Group, South Africa

NASA Astrophysics Data System (ADS)

Maré, L. P.; Eriksson, P. G.; Améglio, L.

2006-01-01

Pole positions from previous palaeomagnetic work in the late Palaeoproterozoic Waterberg Group, South Africa [Jones, D.L., McElhinny, M.W., 1967. Stratigraphic interpretation of paleomagnetic measurements on the Waterberg Red Beds of South Africa. Journal of Geophysical Research 72, 4171-4179] seemed to indicate that Waterberg Group sedimentation commenced during emplacement of the ca. 2.06 Ga Bushveld Complex, and continued intermittently through numerous tectonic events affecting the preserved Transvaal Basin to just before the ca. 1.1 Ga Umkondo thermal event of southern Africa. However, from these studies no consistent directions could be determined. Instead, a pattern was identified and interpreted in terms of apparent polar wander during the deposition and consolidation of the Waterberg sediments within South Africa and Botswana. The Swaershoek Formation, the basal unit of the Waterberg Group in the Nylstroom Protobasin, has been tentatively correlated with the Wilge River Formation, which is the only unit in the Middelburg basin. A new palaeomagnetic study on the Swaershoek and Wilge River Formations is reported here in an attempt to re-determine the palaeomagnetic pole positions for these two formations and to confirm their correlation. A total of 49 sites across both basins were sampled, both within the sedimentary succession and in the associated diabase intrusions. The calculated anti-poles for the Swaershoek Formation (18.9°N, 7.7°E, A95 = 21.9°) and the Wilge River Formation (16.9°N, 0.2°E, A95 = 22.4°) cannot be distinguished at the 95% level of confidence, although scattering is high. This either confirms the geological correlation or indicates simultaneous magnetic overprinting. The results from the two basins are provisionally combined to present a mean pole position for the lower-Waterberg Group. The mean anti-pole for the lower-Waterberg Group is 17.9°N, 3.9°E, A95 = 16.2°. The diabase in both basins was sampled to test for thermal overprinting of the magnetic direction of the sedimentary rocks. Although the calculated anti-pole for the diabase in the Nylstroom Protobasin (63.3°N, 53.2°E and A95 = 35.7°) is poorly determined, its circle of 95% confidence includes the confidence region of the diabase in the Middelburg basin (anti-pole 69.3°N, 28.5°E and A95 = 14.2°). These two poles cannot be distinguished from the results of previous studies on post-Waterberg diabase [Jones, D.L., McElhinny, M.W., 1966. Paleomagnetic correlation of basic intrusions in the Precambrian of Southern Africa. Journal of Geophysical Research 71, 543-552] nor from results of the Umkondo diabase [McElhinny, M.W., Opdyke, N.D., 1964. The palaeomagnetism of the Precambrian dolerites of eastern South Rhodesia. An example of geologic correlation by rock magnetism. Journal of Geophysical Research 69, 2465-2475]. The pole positions from the Waterberg sediment and associated diabase are sufficiently displaced from each other to rule out any overprinting by these intrusions. It does not, however, rule out magnetic overprinting at some earlier or later age. The calculated mean pole position for the lower-Waterberg Group is tentatively interpreted to represent a direction of magnetic overprinting due to the ˜1.88 Ga Palaeoproterozoic intraplate magmatism associated with the Eburnean Event, which means that the cumulative of palaeomagnetic data can no longer connect the onset of Waterberg sedimentation with the emplacement of the Bushveld Complex.

Grid Stiffened Structure Analysis Tool

NASA Technical Reports Server (NTRS)

1999-01-01

The Grid Stiffened Analysis Tool contract is contract performed by Boeing under NASA purchase order H30249D. The contract calls for a "best effort" study comprised of two tasks: (1) Create documentation for a composite grid-stiffened structure analysis tool, in the form of a Microsoft EXCEL spread sheet, that was developed by originally at Stanford University and later further developed by the Air Force, and (2) Write a program that functions as a NASTRAN pre-processor to generate an FEM code for grid-stiffened structure. In performing this contract, Task 1 was given higher priority because it enables NASA to make efficient use of a unique tool they already have; Task 2 was proposed by Boeing because it also would be beneficial to the analysis of composite grid-stiffened structures, specifically in generating models for preliminary design studies. The contract is now complete, this package includes copies of the user's documentation for Task 1 and a CD ROM & diskette with an electronic copy of the user's documentation and an updated version of the "GRID 99" spreadsheet.

Contraction rate, flow modification and bed layering impact on scour at the elliptical guide banks

NASA Astrophysics Data System (ADS)

Gjunsburgs, B.; Jaudzems, G.; Bizane, M.; Bulankina, V.

2017-10-01

Flow contraction by the bridge crossing structures, intakes, embankments, piers, abutments and guide banks leads to general scour and the local scour in the vicinity of the structures. Local scour is depending on flow, river bed and structures parameters and correct understanding of the impact of each parameter can reduce failure possibility of the structures. The paper explores hydraulic contraction, the discharge redistribution between channel and floodplain during the flood, local flow modification and river bed layering on depth, width and volume of scour hole near the elliptical guide banks on low-land rivers. Experiments in a flume, our method for scour calculation and computer modelling results confirm a considerable impact of the contraction rate of the flow, the discharge redistribution between channel and floodplain, the local velocity, backwater and river bed layering on the depth, width, and volume of scour hole in steady and unsteady flow, under clear water condition. With increase of the contraction rate of the flow, the discharge redistribution between channel and floodplain, the local velocity, backwater values, the scour depth increases. At the same contraction rate, but at a different Fr number, the scour depth is different: with increase in the Fr number, the local velocity, backwater, scour depth, width, and volume is increasing. Acceptance of the geometrical contraction of the flow, approach velocity and top sand layer of the river bed for scour depth calculation as accepted now, may be the reason of the structures failure and human life losses.

A model to explain joint patterns found in ignimbrite deposits

NASA Astrophysics Data System (ADS)

Tibaldi, A.; Bonali, F. L.

2018-03-01

The study of fracture systems is of paramount importance for economic applications, such as CO2 storage in rock successions, geothermal and hydrocarbon exploration and exploitation, and also for a better knowledge of seismogenic fault formation. Understanding the origin of joints can be useful for tectonic studies and for a geotechnical characterisation of rock masses. Here, we illustrate a joint pattern discovered in ignimbrite deposits of South America, which can be confused with conjugate tectonic joint sets but which have another origin. The pattern is probably common, but recognisable only in plan view and before tectonic deformation obscures and overprints it. Key sites have been mostly studied by field surveys in Bolivia and Chile. The pattern is represented by hundreds-of-meters up to kilometre-long swarms of master joints, which show circular to semi-circular geometries and intersections that have "X" and "Y" patterns. Inside each swarm, joints are systematic, rectilinear or curvilinear in plan view, and as much as 900 m long. In section view, they are from sub-vertical to vertical and do not affect the underlying deposits. Joints with different orientation mostly interrupt each other, suggesting they have the same age. This joint architecture is here interpreted as resulting from differential contraction after emplacement of the ignimbrite deposit above a complex topography. The set of the joint pattern that has suitable orientation with respect to tectonic stresses may act to nucleate faults.

The Penokean orogeny in the Lake Superior region

USGS Publications Warehouse

Schulz, K.J.; Cannon, W.F.

2007-01-01

The Penokean orogeny began at about 1880 Ma when an oceanic arc, now the Pembine-Wausau terrane, collided with the southern margin of the Archean Superior craton marking the end of a period of south-directed subduction. The docking of the buoyant craton to the arc resulted in a subduction jump to the south and development of back-arc extension both in the initial arc and adjacent craton margin to the north. A belt of volcanogenic massive sulfide deposits formed in the extending back-arc rift within the arc. Synchronous extension and subsidence of the Superior craton resulted in a broad shallow sea characterized by volcanic grabens (Menominee Group in northern Michigan). The classic Lake Superior banded iron-formations, including those in the Marquette, Gogebic, Mesabi and Gunflint Iron Ranges, formed in that sea. The newly established subduction zone caused continued arc volcanism until about 1850 Ma when a fragment of Archean crust, now the basement of the Marshfield terrane, arrived at the subduction zone. The convergence of Archean blocks of the Superior and Marshfield cratons resulted in the major contractional phase of the Penokean orogeny. Rocks of the Pembine-Wausau arc were thrust northward onto the Superior craton causing subsidence of a foreland basin in which sedimentation began at about 1850 Ma in the south (Baraga Group rocks) and 1835 Ma in the north (Rove and Virginia Formations). A thick succession of arc-derived turbidites constitutes most of the foreland basin-fill along with lesser volcanic rocks. In the southern fold and thrust belt tectonic thickening resulted in high-grade metamorphism of the sediments by 1830 Ma. At this same time, a suite of post-tectonic plutons intruded the deformed sedimentary sequence and accreted arc terranes marking the end of the Penokean orogeny. The Penokean orogen was strongly overprinted by younger tectonic and thermal events, some of which were previously ascribed to the Penokean. Principal among these was a period of vertical faulting in the Archean basement and overlying Paleoproterozoic strata. This deformation is now known to have post-dated the terminal Penokean plutons by at least several tens of millions of years. Evidence of the Penokean orogen is now largely confined to the Lake Superior region. Comparisons with more recent orogens formed by similar plate tectonic processes implies that significant parts of a once more extensive Penokean orogen have been removed or overprinted by younger tectonic events. ?? 2007 Elsevier B.V. All rights reserved.

North-South contraction of the mojave block and strike-slip tectonics in southern california.

PubMed

Bartley, J M; Glazner, A F; Schermer, E R

1990-06-15

The Mojave block of southern California has undergone significant late Cenozoic north-south contraction. This previously unappreciated deformation may account for part of the discrepancy between neotectonic and plate-tectonic estimates of Pacific-North American plate motion, and for part of the Big Bend in the San Andreas fault. In the eastern Mojave block, contraction is superimposed on early Miocene crustal extension. In the western Mojave block, contractional folds and reverse faults have been mistaken for extensional structures. The three-dimensional complexity of the contractional structures may mean that rigid-block tectonic models of the region based primarily on paleomagnetic data are unreliable.

A Layered Past: the Transformation and Development of Legacy Sediments as Alluvial Soils

NASA Astrophysics Data System (ADS)

Wade, A.; Richter, D. D., Jr.

2017-12-01

Legacy sediments are a widespread consequence of post-colonial upland erosion in the United States. Although these deposits are ubiquitous in valley bottoms of the southeastern Piedmont, mature hardwood forests and collapsed stream banks mask their occurrence. While these deposits have been studied for their fluvial dynamics and water quality impacts, they have received less attention in regards to soil structure and formation. In this study, we characterized legacy sediment mineraology, composition and structure to understand how pedogenic processes are overprinting sediment layering in a 40-hectare Piedmont floodplain. To constrain the timing of deposition, we used Pb-210 and C-14 dating on buried charcoal and tree stumps. Our results show that in 100 years of forest regeneration, vegetation and oscillating floodplain conditions have driven these eroded sediment deposits to evolve as soil profiles both in structure and composition. These textural and nutrient gradients have ramifications for the subsurface flow of nutrients through the floodplain. Given the estimated millennia it will take to erode legacy sediment from Piedmont floodplains, it is important to think of these deposits as new stable environments on their own trajectory of soil evolution.

Unit: Digging Up Evidence, Inspection Set, National Trial Print.

ERIC Educational Resources Information Center

Australian Science Education Project, Toorak, Victoria.

The teachers' guide to this trial version of a unit prepared by the Australian Science Education Project is an overprinted copy of the students' manual, including comments on the teaching techniques suggested for each activity, lists of recommended references and visual aids, and indications of links with other units produced by the Project. There…

Unit: Tuning in With Our Senses, Inspection Set, National Trial Print.

ERIC Educational Resources Information Center

Australian Science Education Project, Toorak, Victoria.

A preliminary version of this trial draft of a unit prepared for Australian secondary science students was previously announced as ED 049 931 under the short title of "Messengers." The teachers' guide is an overprinted version of the students' booklet, and lists objectives for each section of the materials, indicates possible teaching…

High-pressure crystallization vs. recrystallization origin of garnet pyroxenite-eclogite within subduction related lithologies

NASA Astrophysics Data System (ADS)

Faryad, S. W.; Jedlicka, R.; Hauzenberger, C.; Racek, M.

2018-03-01

Mafic layers displaying transition between clinopyroxenite and eclogite within peridotite from felsic granulite in the Bohemian Massif (Lower Austria) have been investigated. The mafic-ultramafic bodies shared a common granulite facies metamorphism with its hosting felsic rocks, but they still preserve evidence of eclogite facies metamorphism. The selected mafic layer for this study is represented by garnet with omphacite in the core of coarse-grained clinopyroxene, while fine-grained clinopyroxene in the matrix is diopside. In addition, garnet contains inclusions of omphacite, alkali feldspars, hydrous and other phases with halogens and/or CO2. Textural relations along with compositional zoning in garnet from the clinopyroxenite-eclogite layers favour solid-state recrystallization of the precursor minerals in the inclusions and formation of garnet and omphacite during subduction. Textures and major and trace element distribution in garnet indicate two stages of garnet growth that record eclogite facies and subsequent granulite facies overprint. The possible model explaining the textural and compositional changes of minerals is that the granulite facies overprint occurred after formation and exhumation of the eclogite facies rocks.

Mineral shock signatures in rocks from Dhala (Mohar) impact structure, Shivpuri district, Madhya Pradesh, India

NASA Astrophysics Data System (ADS)

Roy, Madhuparna; Pandey, Pradeep; Kumar, Shailendra; Parihar, P. S.

2017-12-01

A concrete study combining optical microscopy, Raman spectroscopy and X-ray diffractometry, was carried out on subsurface samples of basement granite and melt breccia from Mohar (Dhala) impact structure, Shivpuri district, Madhya Pradesh, India. Optical microscopy reveals aberrations in the optical properties of quartz and feldspar in the form of planar deformation feature-like structures, lowered birefringence and mosaics in quartz, toasting, planar fractures and ladder texture in alkali feldspar and near-isotropism in bytownite. It also brings to light incidence of parisite, a radioactive rare mineral in shocked granite. Raman spectral pattern, peak positions, peak widths and multiplicity of peak groups of all minerals, suggest subtle structural/crystallographic deviations. XRD data further reveals minute deviations of unit cell parameters of quartz, alkali feldspar and plagioclase, with respect to standard α-quartz, high- and low albite and microcline. Reduced cell volumes in these minerals indicate compression due to pressure. The c0/a0 values indicate an inter-tetrahedral angle roughly between 120o and 144o, further pointing to a possible pressure maxima of around 12 GPa. The observed unit cell aberration of minerals may indicate an intermediate stage between crystalline and amorphous stages, thereby, signifying possible overprinting of decompression signatures over shock compression effects, from a shock recovery process.

76 FR 36583 - New Postal Product

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-22

... Docket No. CP2010-36 serve as the baseline contract for future functional equivalence analyses of the... commitments, do not alter the contract's functional equivalency. Id. at 4. The Postal Service asserts that... offered or the fundamental structure of the contract. Therefore, it requests that the instant contract be...

U-Pb zircon and 40Ar/39Ar geochronology of sericite from hydrothermal alteration zones: new constraints for the timing of Ediacaran gold mineralization in the Sukhaybarat area, western Afif terrane, Saudi Arabia

NASA Astrophysics Data System (ADS)

Harbi, Hesham M.; Ali, Kamal A.; McNaughton, Neal J.; Andresen, Arild

2018-04-01

The Sukhaybarat East and Red Hill deposits, in the northeastern part of the Arabian Shield, are mesothermal vein-type gold deposits hosted by late Cryogenian-Ediacaran intrusive rocks of the Idah suites (diorite, tonalite, granodiorite) and, at Sukhaybarat East, also by Ediacaran metasedimentary rocks. Gold mineralization comprises quartz-arsenopyrite veins (Sukhaybarat East), quartz-carbonate-pyrite veins (Red Hill), and subordinate gold-base metal sulfide veins. In the Red Hill deposit, alteration is complicated due to multiple overprinting hydrothermal events and is characteristically affected by pervasive, pink quartz-K-feldspar-hematite alteration which is overprinted by potassic alteration characterized by a quartz-biotite-carbonate-muscovite/sericite-rutile-apatite assemblage. This assemblage is associated with molybdenite veins which appear to form late in the paragenetic sequence and may represent either evolution of the ore fluid composition, or a later, unrelated mineralized fluids. Hydrothermal alteration at the Sukhaybarat East deposit is dominated by quartz-carbonate-sericite-arsenopyrite assemblages. Zircon from ore-hosting tonalite at Sukhaybarat East yields a U-Pb age of 629 ± 6 Ma, and biotite from the same rock gives an 40Ar/39Ar age of 622 ± 23 Ma. The 40Ar/39Ar age is within the uncertainty range for the U-Pb age of the host intrusion and is interpreted as a minimally disturbed cooling age for the tonalite. In the Red Hill area, granodiorite was emplaced at 615 ± 5 Ma, whereas muscovite/sericite separated from a mineralized sample of a quartz-carbonate-pyrite vein, that was overprinted by molybdenite-bearing veinlets, yields an 40Ar/39Ar age of 597 ± 8 Ma. We interpreted this age to represent the maximum age of the molybdenite mineralization and the probable minimum age of gold mineralization in the Red Hill deposit.

Multiphase boudinage: a case study of amphibolites in marble in the Naxos migmatite core

NASA Astrophysics Data System (ADS)

Virgo, Simon; von Hagke, Christoph; Urai, Janos L.

2018-02-01

In multiply deformed terrains multiphase boudinage is common, but identification and analysis of these is difficult. Here we present an analysis of multiphase boudinage and fold structures in deformed amphibolite layers in marble from the migmatitic centre of the Naxos metamorphic core complex. Overprinting between multiple boudinage generations is shown in exceptional 3-D outcrop. We identify five generations of boudinage, reflecting the transition from high-strain high-temperature ductile deformation to medium- to low-strain brittle boudins formed during cooling and exhumation. All boudin generations indicate E-W horizontal shortening and variable direction of bedding parallel extension, evolving from subvertical extension in the earliest boudins to subhorizontal N-S extension during exhumation. Two phases of E-W shortening can be inferred, the first associated with lower crustal synmigmatic convergent flow and the second associated with exhumation and N-S extension, possibly related to movement of the North Anatolian Fault.

Possible Mesozoic age of Ellenville Zn-Pb-Cu(Ag) deposit, Shawangunk Mountains, New York

USGS Publications Warehouse

Friedman, J.D.; Conrad, J.E.; McKee, E.H.; Mutschler, F.E.; Zartman, R.E.

1994-01-01

Ore textures, epithermal open-space filling of Permian structures of the Alleghanian orogeny, and largely postorogenic mineralization of the Ellenville, New York, composite Zn-Pb-Cu(Ag) vein system, provide permissive evidence for post-Permian mineralization. Isochron ages determined by 40Ar/39Ar laser-fusion techniques for K-bearing liquid inclusions in main-stage quartz from the Ellenville deposit additionally suggest a Mesozoic time of mineralization, associated with extensional formation of the Newark basin. The best 40Ar/39Ar total-fusion age range is 165 ?? 30 to 193 ?? 35 Ma. The Mesozoic 40Ar/39Ar age agrees with that of many other dated northern Appalachian Zn-Pb-Cu(Ag) deposits with near-matching lead isotope ratios, and adds new evidence of Jurassic tectonism and mineralization as an overprint to Late Paleozoic tectonism at least as far north as Ellenville (lat. 41??43???N). ?? 1994 Springer-Verlag.

Oscillating brittle and viscous behavior through the earthquake cycle in the Red River Shear Zone: Monitoring flips between reaction and textural softening and hardening

NASA Astrophysics Data System (ADS)

Wintsch, Robert P.; Yeh, Meng-Wan

2013-03-01

Microstructures associated with cataclasites and mylonites in the Red River shear zone in the Diancang Shan block, Yunnan Province, China show evidence for both reaction hardening and softening at lower greenschist facies metamorphic conditions. The earliest fault-rocks derived from Triassic porphyritic orthogneiss protoliths are cataclasites. Brittle fractures and crushed grains are cemented by newly precipitated quartz. These cataclasites are subsequently overprinted by mylonitic fabrics. Truncations and embayments of relic feldspars and biotites show that these protolith minerals have been dissolved and incompletely replaced by muscovite, chlorite, and quartz. Both K-feldspar and plagioclase porphyroclasts are truncated by muscovite alone, suggesting locally metasomatic reactions of the form: 3K-feldspar + 2H+ = muscovite + 6SiO2(aq) + 2K+. Such reactions produce muscovite folia and fish, and quartz bands and ribbons. Muscovite and quartz are much weaker than the reactant feldspars and these reactions result in reaction softening. Moreover, the muscovite tends to align in contiguous bands that constitute textural softening. These mineral and textural modifications occurred at constant temperature and drove the transition from brittle to viscous deformation and the shift in deformation mechanism from cataclasis to dissolution-precipitation and reaction creep. These mylonitic rocks so produced are cut by K-feldspar veins that interrupt the mylonitic fabric. The veins add K-feldspar to the assemblage and these structures constitute both reaction and textural hardening. Finally these veins are boudinaged by continued viscous deformation in the mylonitic matrix, thus defining a late ductile strain event. Together these overprinting textures and microstructures demonstrate several oscillations between brittle and viscous deformation, all at lower greenschist facies conditions where only frictional behavior is predicted by experiments. The overlap of the depths of greenschist facies conditions with the base of the crustal seismic zone suggests that the implied oscillations in strain rate may have been related to the earthquake cycle.

Variscan tectonics in Dodecanese, Kalymnos island, Greece

NASA Astrophysics Data System (ADS)

Chatziioannou, Eleftheria; Grasemann, Bernhard; Schneider, David; Hubmann, Bernhard; Soukis, Konstantinos

2015-04-01

Kalymnos island is located in the Dodecanese, southeastern Aegean Sea, and geologically appears to be part of the external Hellenides. Pre-Alpidic basement rocks on the Dodecanese islands have been suggested to record compelling similarities with the basement rocks in Eastern Crete with respect to their lithologies and pre-Alpidic metamorphic evolution. The lithotectonic units experienced greenschist to amphibolite facies conditions during the Variscan orogeny. Whereas the rocks in Eastern Crete reveal Alpine high-pressure overprint, the Variscan basement units in the Dodecanese record no or low-grade Alpine metamorphism. A field study of basement rocks below Mesozoic limestones and dolomites in the NW part of Kalymnos near Emporios uncovered a complex history of metamorphism, folding and faulting. Three different tectonic units can be discriminated from top to bottom: a) a quartz-mica schist, b) a white-grey, fossiliferous coarse grained marble and c) a fine-grained fossiliferous blue-grey marble. In the marbles macrofossils such as brachiopods, ammonoid cephalopods (Goniatids?) and crinoids suggest a Middle-Upper Devonian deposition age (Givetian- Frasnian). Structural mapping the area resolved a dominant W-E shortening event, resulting in an overall inverted metamorphic gradient. The lowermost blue-grey marble unit is folded into large-scale upright folds, which are truncated by top-to-east overthrusting of the white-grey marble unit. Whereas deformation mechanisms in the blue-grey marble unit are dominated by dissolution-precipitation creep, the white-grey marble suffered intense crystal plastic deformation with localized high-strain mylonitic shear zones. The uppermost quartz-mica schist unit is separated from the lower units by a cataclastic phyllonitic shear zone. 40Ar/39Ar geochronological dating on white micas from the quartz-mica schists yielded cooling ages between 240 and 334 Ma indicative of Variscan cooling. Our data suggest that this part of the Dodecanese experienced intense Variscan deformation with no high-temperature Alpine overprint.

Multiple tectonic mode switches indicate short-duration heat pulses in a Mio-Pliocene metamorphic core complex, West Papua, Indonesia

NASA Astrophysics Data System (ADS)

White, L. T.; Hall, R.; Gunawan, I.

2017-12-01

The Wandaman Peninsula is a narrow (<20 km), but mountainous (>2 km) promontory in remote western New Guinea. The peninsula is almost entirely composed of medium- to high-grade metamorphic rocks considered to be associated with a Mio-Pliocene metamorphic core complex. Previous work has shown that the uplift and exhumation of the core complex has potentially brought some extremely young eclogite to the surface. These might be comparable to the world's youngest (4.3 Ma) eclogites found in the D'Entrecasteaux Islands at the opposite end of New Guinea. We show that tectonic history of this region is complex. This is because the metamorphic sequences in the Wandaman Peninsula record multiple phases of deformation, all within the last few million years. This is demonstrated through methodical collation of cross-cutting relations from field and microstructural studies across the peninsula. The first phase of deformation and metamorphism is associated with crustal extension and partial melting that took place at 5-7 Ma according to new U-Pb data from metamorphic zircons. This extensional phase ceased after a tectonic mode switch and the region was shortened. This is demonstrated by two phases of folding (1. recumbent and 2. open) that overprint the earlier extensional fabrics. All previous structures were later overprinted by brittle extensional faults and uplift. This extensional phase is still taking place today, as is indicated by submerged forests exposed along the coastline associated with recent earthquakes and hot springs. The sequence of metamorphic rocks that are exposed in the Wandaman Peninsula show that stress and thermal conditions can change rapidly. If we consider that the present is a key to the past, then such results can identify the duration of deformation and metamorphic events more accurately than in much older orogenic systems.

Alpine extensional detachment tectonics in the Grande Kabylie metamorphic core complex of the Maghrebides (northern Algeria)

NASA Astrophysics Data System (ADS)

Saadallah, A.; Caby, R.

1996-12-01

The Maghrebides are part of the peri-Mediterranean Alpine orogen. They expose in their inner zone inliers of high-grade crystalline rocks surrounded by Oligo-Miocene and younger Miocene cover. Detailed mapping coupled with structural and petrological investigations in the Grande Kabylie massif, and the reinterpretation of the available geochronological data, allow us to refute the traditional concept of rigid behaviour of this massif during Alpine events. We show that the dome geometry, the kinematic and metamorphic evolutions and the age pattern are typical of metamorphic core complexes exhumed by extension. A major low-angle detachment fault defined by mylonites and by younger cataclasites has been traced in the massif. The upper unit encompasses pre-Permian phyllites with Variscan {40Ar }/{39Ar } cooling ages, capped by unconformable Mesozoic to Tertiary cover of the Calcareous Range, both mainly affected by extensive Tertiary brittle deformation and normal faulting. The lower unit exposes in two half-domes a continuous tectonic pile, 6-8 km thick, of amphibolite facies rocks and orthogneisses affected by syndashmetamorphic ductile deformation, devoid of retrogression. The regular increase of paleotemperature downward and the {40Ar }/{39Ar } plateau ages around 80 Ma suggest that the high-temperature foliation and associated WNW-directed shear under a high geothermal gradient relate to extensional tectonics developed during Mesozoic lithospheric thinning of the Variscan south European margin. To the north, the Sidi Alli Bou Nab massif exposes another crustal section affected throughout by WNW-directed extensional shear during {HP }/{HT } syndashmetamorphic thinning and with overall {40Ar }/{39Ar } plateau ages of 25 Ma. The Eocene oblique collisional event responsible for crustal thickening was totally overprinted by this new extensional regime, synchronous with the beginning of the opening of the Western Mediterranean oceanic basin. This was also coeval with south-directed thrusting of foreland nappes to the south. Post-Miocene tectonic events cause significant overprinting.

Diverging Histories of the Liberty Creek and Iceberg Lake Blueschist Bodies, south central Alaska

NASA Astrophysics Data System (ADS)

Day, E. M.; Pavlis, T. L.; Amato, J. M.

2011-12-01

New studies of the Liberty Creek and Iceberg Lake blueschist bodies of south central Alaska indicate that despite structural similarities, these blueschist bodies are derived from a different protolith and were metamorphosed to blueschist facies at distinctly different times. Both blueschists are located just south of the Border Ranges Fault (BRF) within outcrop belts of the McHugh Complex, a low-grade mélange assemblage that is now known from detrital zircon studies to consist of two distinct assemblages: a Jurassic to Earliest Cretaceous assemblage and a Late Cretaceous assemblage. The BRF is a megathrust system that represents the Late Triassic-Early Jurassic initiation of southern Alaskan subduction. Large scale (1:24,000) mapping revealed similar fabric overprint histories, epitomized by a previously undescribed youngest vertical N-S trending crenulation cleavage in both blueschist bodies which implies a structural correlation despite their separation of ~100 kilometers along strike. Despite structural similarities detrital zircon studies show that the Liberty Creek and Iceberg Lake blueschists do not have a similar maximum age of deposition. Thirteen samples from the Iceberg Lake blueschist were processed, none of which produced detrital zircons. Samples from the McHugh Complex greenschists that surround the Iceberg Lake blueschist produced numerous zircons indicating a Late Jurassic (~160 Ma) maximum age of deposition. Three out of sixteen samples from the Liberty creek blueschist produced detrital zircons indicating maximum depositional ages ranging from Late Jurassic (~160.1 Ma, n=64 grains; ~152.25 Ma, n=68 grains) to Early Cretaceous (~137.1 Ma, n=95 grains). The Late Jurassic dates are consistent with maximum depositional ages determined by Amato and Pavlis (2010) for McHugh Complex rocks along Turnagain Arm near Anchorage, AK. Sisson and Onstott (1986) reported a metamorphic cooling age of 185 Ma for the Iceberg Lake blueschist, thus, although no depostitional age constraints were obtained for the Iceberg Lake body, its metamorphic cooling age is far older than the younger depositional ages of the Liberty Creek blueschists indicating these areas record two different blueschist facies metamorphic assemblages. Work in progress on cooling ages from the Liberty Creek rocks should clarify the age of this younger metamorphism. Although these assemblages record different metamorphic events, the similar overprint history may indicate that the Liberty Creek and Iceberg Lake blueschists were subjected to the same, younger deformation series, possibly Cenozoic strike-slip related deformation.

A Transect Across the Greater Himalayan Sequence of Bhutan: Evidence for a Minimum of 10 Ma of Ductile Flow Between the Outer South Tibetan Detachment and the Main Central Thrust

NASA Astrophysics Data System (ADS)

Daniel, C. G.; Kim, Y.; Grujic, D.; Hollister, L. S.

2011-12-01

Unique features of the Bhutan Himalaya are klippen of Tethyan sediments that overlie sillimanite and kyanite gneisses of the Greater Himalayan Sequence (GHS). The contact is strongly sheared, and referred to as the Outer South Tibetan Detachment (O-STD). Five such klippen are preserved in Bhutan and give insight into the Miocene displacement (ca. 24-11 Ma) of the STD system and on the evolution of the uppermost GHS. The base of the klippen are characterized by strongly sheared Grt-Bt±St±Sil schists of the Chekha Formation that appear to grade continuously upward into the black slates and weakly- to unmetamorphosed rocks of the Tethyan Sedimentary Sequence (TSS). Leucogranites intrude the Chekha Fm and the GHS in the vicinity of the contact, but not the TSS. New metamorphic, structural and geochronologic data from the western side of the Tang Chu klippe show that deformation and metamorphism within the Chekha Fm. were underway prior to 17.6 Ma, and that ductile shearing clearly overprints peak metamorphic mineral assemblages and continued until after 14 Ma. These data, when combined with previously reported data from adjacent klippen and the Main Central Thrust Zone to the south, provide a record of fairly continuous ductile flow of the GHS between 25-23 Ma and 13-11 Ma, at which point displacement transfers north of the klippen, to the Kakhtang thrust and the Inner-STD. Samples for this study were collected along a 10 km traverse and include four samples of Chekha Fm. and two samples of GHS collected across an ~ 80 m structural section that straddles the O-STD. The top of the interval starts in the Chekha Fm. and is characterized by the assemblage Grt-Bt-St, with a peak temperature near 600 °C. The base of the Chekha Fm. preserves Grt-Bt-Ms, with minor Sil, and peak temperatures near 650 °C; no evidence of partial melting is observed. The GHS samples are characterized by Grt-Bt-Ms-Sil and were partially melted. Peak metamorphic temperatures are estimated to be 650-750 °C. No pressure break is observed across the O-STD, and all peak temperatures correspond to a pressure of 6-7 kbar. In-situ, monazite SHRIMP U-Pb ages for the Chekha Fm. range from about 16.58 Ma ± 0.22 Ma (2σ) at the top of the interval to about 17.58 Ma ± 0.47 Ma (2σ) near its base. Apparent ages from monazite in the GHS range from 21.0 Ma ± 0.7 Ma (1σ) to 13.9 Ma ± 0.4 Ma (1σ). Deformation outlasts metamorphism, as indicated by pre- to syn-kinematic porphyroblasts overprinted by shear bands. Samples from the Chekha Fm. show top-to-north extensional displacement at the top of the interval and conjugate top-to-north and top-to-south shearing indicative of flattening at the base. The GHS samples show dominantly top-to-south shearing overprinted by minor top-to-north shearing. The simultaneous displacement across the GHS and O-STD, the compression of isotherms, and the absence of a discrete pressure break across the O-STD are consistent with a model of ductile flow and extrusion.

Innovative uses for municipal investment contracts.

PubMed

Smith, S D

1994-01-01

This article describes the benefits of using municipal investment contracts for the reinvestment of municipal bond proceeds. It shows how municipal investment contracts may be structured to meet a borrower's objectives of liquidity, security, and maximization of investment yield. Several examples show how a custom-tailored municipal investment contract may achieve results unobtainable through traditional investment vehicles.

Toda theories as contractions of affine Toda theories

NASA Astrophysics Data System (ADS)

Aghamohammadi, A.; Khorrami, M.; Shariati, A.

1996-02-01

Using a contraction procedure, we obtain Toda theories and their structures, from affine Toda theories and their corresponding structures. By structures, we mean the equation of motion, the classical Lax pair, the boundary term for half line theories, and the quantum transfer matrix. The Lax pair and the transfer matrix so obtained, depend nontrivially on the spectral parameter.

[Remunerations, benefits and labor incentives perceived by health care workers in Peru: an analysis comparing the Ministry of Health and the Social Insurance, 2009].

PubMed

Pardo, Karim; Andia, Marcelino; Rodriguez, Amado; Pérez, Walter; Moscoso, Betsy

2011-06-01

To describe the main characteristics of the general salaries situation and the incentive policies of health care workers of Peru, comparing them by their origin institution and type of contract. A mixed design study was done including both quantitative and qualitative components during 2008 and 2009 with both professional and technical personnel of the Ministry of Health (MINSA) and the Social Insurance (EsSalud) in Peru. The salary structure was primarily evaluated considering incentives, bonuses and other remunerations according to position, type of contract and work place. Remuneration and bonus policies at the national level are determined by the responsibilities and amount of time served. The type of contract is determined by the programs of the public system (DL 276) and the private system (DL 728), also by the Special Program of Contract Services Administration (CAS) and exclusively in MINSA contracting is determined by local health administration Committees (CLAS). The salary structure differs between both types of institutions, especially with respect to incentives and benefits. An special economic incentive for assistance (AETA) is unique to MINSA, but the proportion of assistance varies by region. The professionals of MINSA have lower salaries than those of EsSalud, in all types of contracts. A professional contracted through CAS generally has a lower salary than staff peers in MINSA, though this situation is reversed in EsSalud. The lowest salaries are found in contracts made through CLAS. The structure and salary amounts differ between MINSA and EsSalud, just as they differ by existing contracting types.

Understanding the Mechanical Properties and Structure Transition of Antheraea pernyi Silk Fiber Induced by Its Contraction.

PubMed

Wang, Yu; Wen, Jianchuan; Peng, Bo; Hu, Bingwen; Chen, Xin; Shao, Zhengzhong

2018-02-23

Like most major ampullate silks of spider, the length of Antheraea pernyi silkworm silk can shrink to a certain degree when the fiber is in contact with water. However, what happens in terms of molecule chain level and how it correlates to the mechanical properties of the silk during its contraction is not yet fully understood. Here, we investigate the water-induced mechanical property changes as well as the structure transition of two kinds of A. pernyi silk fiber, which are forcibly reeled from two different individuals (silkworm a and silkworm b; the silk fiber from either one represents the lower and upper limit of the distribution of mechanical properties, respectively). The tensile test results present that most of the mechanical parameters except the post-yield modulus and breaking strain for both silk fibers have the same variation trend before and after their water contraction. Synchrotron FTIR and Raman spectra show that the native filament from silkworm a contains more α-helix structures than that in silkworm b filament, and these α-helices are partially converted to β-sheet structures after the contraction of the fibers, while the order of both β-sheet and α-helix slightly increase. On the other side, the content and orientation of both secondary structural components in silkworm b fiber keep unchanged, no matter if it is native or contracted. 13 C CP/MAS NMR results further indicate that the α-helix/random coil to β-sheet conformational transition that occurred in the silk of silkworm a corresponds the Ala residues. Based upon these results, the detailed structure transition models of both as-reeled A. pernyi silk fibers during water contraction are proposed finally to interpret their properties transformation.

The tail sheath structure of bacteriophage T4: a molecular machine for infecting bacteria

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

Aksyuk, Anastasia A.; Leiman, Petr G.; Kurochkina, Lidia P.

2009-07-22

The contractile tail of bacteriophage T4 is a molecular machine that facilitates very high viral infection efficiency. Its major component is a tail sheath, which contracts during infection to less than half of its initial length. The sheath consists of 138 copies of the tail sheath protein, gene product (gp) 18, which surrounds the central non-contractile tail tube. The contraction of the sheath drives the tail tube through the outer membrane, creating a channel for the viral genome delivery. A crystal structure of about three quarters of gp18 has been determined and was fitted into cryo-electron microscopy reconstructions of themore » tail sheath before and after contraction. It was shown that during contraction, gp18 subunits slide over each other with no apparent change in their structure.« less

An Organizational Climate Assessment of the Army Contracting Workforce

DTIC Science & Technology

2016-12-01

WITHIN THE ARMY ............................32  L.  THE ARMY CONTRACTING STRUCTURE AND ITS ORGANIZATIONAL CLIMATE...describes the dimensions used to assess organizational climate. Responses to a web- based survey administered to the Army’s contracting workforce...workforce. Based on the survey results, this project provides an assessment of the Army’s contracting workforce organizational climate. Additionally

Joint Implications for Contracted Logistics

DTIC Science & Technology

2007-03-30

authority with the host nation country and policy on using UCMJ for contracted personnel. As tailored theater policies are developed and contracting...responsibility, this paper recommends better joint training, leader development and joint enablers for contracting operations. JOINT...U.S. Joint Forces Command (JFCOM) are analyzing Congressional and DOD policy to develop procedures and force structure to support contractor

Geometric description and analysis of metamorphic tectonites (Pelagonian Zone, Internal Hellenides, Northern Greece)

NASA Astrophysics Data System (ADS)

Diamantopoulos, A.

2009-04-01

An assortment of alpine and pre-Permian metamorphic tectonites, belonging to the Pelagonian Zone of the Internal Hellenides, are analyzed from Askion, Vernon and Vorras mountains. They in fact compose the Upper plate of the Western Macedonia core complex, overlying Late Tertiary high-P rocks through large-scale detachment fautls (Diamantopoulos et al. 2007). This work wants to determine the architecture and the kinematic path of rocks in a 3D assumption. Field analysis concludes: a) Meta-sedimentary lithologies and amphibolites, meta-igneous lithologies, granitoid mylonites composed of augen fieldspar gneisses, Permo-Triassic fossiliferous rocks, meta-carbonates of Triassic-Jurassic age, a Jurassic mélange including meta-sedimentary lithologies, serpentinites and carbonate tectonic blocks, Mesozoic Ophiolites, Cretaceous limestones and conglomerates as well as flysch sediments compose the architecture of the study area, b) Multiple high and low-angle cataclastic zones of intense non-coaxial strain separate distinct pre-Permian lithologies, alpine from pre-alpine rocks, Triassic-Jurassic rocks from Permo-Triassic rocks, Jurassic mélange from flysch sediments, Jurassic mélange from Triassic-Jurassic rocks, Cretaceous rocks from the Jurassic mélange, Cretaceous limestones from flysch lithologies and Cretaceous rocks from serpentinites, c) Geometric analysis and description of asymmetric structures found in fault cores, damage zones and in the footwall-related rocks showed a prominent kinematic direction towards WSW in low-T conditions affected all the rock lithologies, d) Multiple S- and L- shape fabric elements in the pre-Permian and Permo-Triassic rocks appear an intricate orientation, produced by intense non-coaxial syn-metamorphic deformation, e) Sheath and isoclinal folds oriented parallel to the L-shape fabric elements as well as a major S-shape fabric element, producing macroscopic fold-like structures compose the main syn-metamorphic fabric elements in the pre-alpine tectonites, f) Discrete and distributed strain along the former boundaries and within footwall- and hangingwall rocks is connoted to control the bulk kinematic path of the involved sequences, g) Field evaluation of the structural geology and the tectonics connote the conjugate character of the cataclastically-deformed boundaries, causing overprinting of the pre-existed ductile-related geometries, h) For the age of the inferred WSW kinematic direction of the involved rocks we believe that it is closely associated with the tectonic superimposition of the Pelagonian Zone onto the Olympos tectonic window during post-Late Eocene times. Miocene to Quaternary faulting activity in all the scales overprint the above Late Tertiary perturbation, resulting a real complicated structural feature (Diamantopoulos 2006). Diamantopoulos A., 2006. Plio-Quaternary geometry and Kinematics of Ptolemais basin (Northern Greece). Implications for the intra-plate tectonics in Western Macedonia. Geologica Croatica 59/1, pages 85-96. Diamantopoulos A., Krohe A., Mposkos E., 2007. Structural asymmetry and distributed strain of low-T shear planes inducing evidence for orogen-scale kinematic partitioning during denudation of high-P rocks (Pelagonian Zone, Greece). Geophysical Research Abstracts, Vol. 9, 03622.

Multi-crease Self-folding by Global Heating.

PubMed

Miyashita, Shuhei; Onal, Cagdas D; Rus, Daniela

2015-01-01

This study demonstrates a new approach to autonomous folding for the body of a 3D robot from a 2D sheet, using heat. We approach this challenge by folding a 0.27-mm sheetlike material into a structure. We utilize the thermal deformation of a contractive sheet sandwiched by rigid structural layers. During this baking process, the heat applied on the entire sheet induces contraction of the contracting layer and thus forms an instructed bend in the sheet. To attain the targeted folding angles, the V-fold spans method is used. The targeted angle θout can be kinematically encoded into crease geometry. The realization of this angle in the folded structure can be approximately controlled by a contraction angle θin. The process is non-reversible, is reliable, and is relatively fast. Our method can be applied simultaneously to all the folds in multi-crease origami structures. We demonstrate the use of this method to create a lightweight mobile robot.

Reconnaissance survey of the Duolun ring structure in Inner Mongolia: Not an impact structure

NASA Astrophysics Data System (ADS)

Xu, Xiaoming; Kenkmann, Thomas; Xiao, Zhiyong; Sturm, Sebastian; Metzger, Nicolai; Yang, Yu; Weimer, Daniela; Krietsch, Hannes; Zhu, Meng-Hua

2017-09-01

The Duolun basin, which is located in Inner Mongolia, China, has been proposed to be an impact structure with an apparent rim diameter of about 70, or even 170 km. The designation as an impact structure was based on its nearly circular topography, consisting of an annular moat that surrounds an inner hummocky region, and the widespread occurrences of various igneous rocks, polymict breccias, and deformed crustal rocks. Critical shock metamorphic evidence is not available to support the impact hypothesis. We conducted two independent reconnaissance field surveys to this area and studied the lithology both within and outside of the ring structure. We collected samples from all lithologies that might contain evidence of shock metamorphism as suggested by their locations, especially those sharing similar appearances with impact breccias, suevites, impact melt rocks, and shatter cones. Field investigation, together with thin-section examination, discovered that the suspected impact melt rocks are actually Early Cretaceous and Late Jurassic lava flows and pyroclastic deposits of rhyolitic to trachytic compositions, and the interpreted impact glass is typical volcanic glass. Petrographic analyses of all the samples reveal no indications for shock metamorphic overprint. All these lines of evidence suggest that the Duolun basin was not formed through impact cratering. The structural deformation and spatial distribution pattern of the igneous rocks suggest that the Duolun basin is most likely a Jurassic-Cretaceous complex rhyolite caldera system that has been partly filled with sediments forming an annular basin, followed by resurgent doming of the central area.

Scale and structure of capitated physician organizations in California.

PubMed

Rosenthal, M B; Frank, R G; Buchanan, J L; Epstein, A M

2001-01-01

Physician organizations in California broke new ground in the 1980s by accepting capitated contracts and taking on utilization management functions. In this paper we present new data that document the scale, structure, and vertical affiliations of physician organizations that accept capitation in California. We provide information on capitated enrollment, the share of revenue derived by physician organizations from capitation contracts, and the scope of risk sharing with health maintenance organizations (HMOs). Capitation contracts and risk sharing dominate payment arrangements with HMOs. Physician organizations appear to have responded to capitation by affiliating with hospitals and management companies, adopting hybrid organizational structures, and consolidating into larger entities.

Origin of magnetization in lunar breccias - An example of thermal overprinting

NASA Technical Reports Server (NTRS)

Gose, W. A.; Strangway, D. W.; Pearce, G. W.

1978-01-01

Twenty six samples from seven hand specimens, collected from the station 6 boulder at the Apollo 17 landing site, were studied magnetically. The boulder is a breccia consisting of three lithologic units distinguished by their clast population. The direction of magnetization of samples from unit B which is almost devoid of large clasts cluster fairly well after alternating field demagnetization. Samples from unit C which is characterized by abundant large clasts up to 1 m in size do not contain a uniform direction of magnetization but the distribution is not random. Based on these data we propose that the natural remanent magnetization (NRM) in these breccias is the vector sum of two magnetizations, a pre-impact magnetization and a partial thermoremanence acquired during breccia formation. The relative contribution of the two components is controlled by the thermal history of the ejecta, which in turn is determined by its clast population. Depending on the clast population, the NRM can be a total thermoremanence, a partial thermoremanence plus a pre-impact magnetization, or a pre-impact magnetization. This model of thermal overprinting might be applicable to all lunar breccias of medium and higher metamorphic grade.

48 CFR 16.402-4 - Structuring multiple-incentive contracts.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Structuring multiple-incentive contracts. 16.402-4 Section 16.402-4 Federal Acquisition Regulations System FEDERAL ACQUISITION... include a cost incentive (or constraint) that operates to preclude rewarding a contractor for superior...

Evolution of the Mount Woods Inlier, northern Gawler Craton, Southern Australia: an integrated structural and aeromagnetic analysis

NASA Astrophysics Data System (ADS)

Betts, Peter G.; Valenta, Rick K.; Finlay, Jim

2003-05-01

Structural mapping integrated with interpretation and forward modelling of aeromagnetic data form complimentary and powerful tools for regional structural analysis because both techniques focus on architecture and overprinting relationships. This approach is used to constrain the geometry and evolution of the sparsely exposed Mount Woods Inlier in the northern Gawler Craton. The Mount Woods Inlier records a history of poly-phase deformation, high-temperature metamorphism, and syn- and post-orogenic magmatism between ca. 1736 and 1584 Ma. The earliest deformation involved isoclinal folding, and the development of bedding parallel and axial planar gneissic foliation (S 1). This was accompanied by high-temperature, upper amphibolite to granulite facies metamorphism at ca. 1736 Ma. During subsequent north-south shortening (D 2), open to isoclinal south-southeast-oriented F 2 folds developed as the Palaeoproterozoic successions of the inlier were thrust over the Archaean nuclei of the Gawler Craton. The syn-D 2 Engenina Adamellite was emplaced at ca. 1692 Ma. The post-D 2 history involved shear zone development and localised folding, exhumation of metamorphic rocks, and deposition of clastic sediments prior to the emplacement of the ca. 1584 Ma Granite Balta Suite. The Mount Woods Inlier is interpreted as the northern continuation of the Kimban Orogen.

Structural features of northern Tarim basin: Implications for regional tectonics and petroleum traps

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

Dong Jia; Juafu Lu; Dongsheng Cai

1998-01-01

The rhombus-shaped Tarim basin in northwestern China is controlled mainly by two left-lateral strike-slip systems: the northeast-trending Altun fault zone along its southeastern side and the northeast-trending Aheqi fault zone along its northwestern side. In this paper, we discuss the northern Tarim basin`s structural features, which include three main tectonic units: the Kalpin uplift, the Kuqa depression, and the North Tarim uplift along the northern margin of the Tarim basin. Structural mapping in the Kalpin uplift shows that a series of imbricated thrust sheets have been overprinted by strike-slip faulting. The amount of strike-slip displacement is estimated to be 148more » km by restoration of strike-slip structures in the uplift. The Kuqa depression is a Mesozoic-Cenozoic foredeep depression with well-developed flat-ramp structures and fault-related folds. The Baicheng basin, a Quaternary pull-apart basin, developed at the center of the Kuqa depression. Subsurface structures in the North Tarim uplift can be divided into the Mesozoic-Cenozoic and the Paleozoic lithotectonic sequences in seismic profiles. The Paleozoic litho-tectonic sequence exhibits the interference of earlier left-lateral and later right-lateral strike-slip structures. Many normal faults in the Mesozoic-Cenozoic litho-tectonic sequence form the negative flower structures in the North Tarim uplift; these structures commonly directly overlie the positive flower structures in the Paleozoic litho-tectonic sequence. The interference regions of the northwest-trending and northeast-trending folds in the Paleozoic tectonic sequence have been identified to have the best trap structures. Our structural analysis indicates that the Tarim basin is a transpressional foreland basin rejuvenated during the Cenozoic.« less

Clot contraction: compression of erythrocytes into tightly packed polyhedra and redistribution of platelets and fibrin

PubMed Central

Cines, Douglas B.; Lebedeva, Tatiana; Nagaswami, Chandrasekaran; Hayes, Vincent; Massefski, Walter; Litvinov, Rustem I.; Rauova, Lubica; Lowery, Thomas J.

2014-01-01

Contraction of blood clots is necessary for hemostasis and wound healing and to restore flow past obstructive thrombi, but little is known about the structure of contracted clots or the role of erythrocytes in contraction. We found that contracted blood clots develop a remarkable structure, with a meshwork of fibrin and platelet aggregates on the exterior of the clot and a close-packed, tessellated array of compressed polyhedral erythrocytes within. The same results were obtained after initiation of clotting with various activators and also with clots from reconstituted human blood and mouse blood. Such close-packed arrays of polyhedral erythrocytes, or polyhedrocytes, were also observed in human arterial thrombi taken from patients. The mechanical nature of this shape change was confirmed by polyhedrocyte formation from the forces of centrifugation of blood without clotting. Platelets (with their cytoskeletal motility proteins) and fibrin(ogen) (as the substrate bridging platelets for contraction) are required to generate the forces necessary to segregate platelets/fibrin from erythrocytes and to compress erythrocytes into a tightly packed array. These results demonstrate how contracted clots form an impermeable barrier important for hemostasis and wound healing and help explain how fibrinolysis is greatly retarded as clots contract. PMID:24335500

[Thin filament elasticity and its role in the muscle contraction].

PubMed

Skubiszak, L

2006-01-01

The available experimental methods do not allow one to establish unambiguously the molecular structural events during muscle contraction. To resolve the existing controversies, I have devised an unconventional original computer program. The new approach allows the reconstruction of the hexagonal lattice of the sarcomere for different muscle states and verification of the structure by comparison of the calculated Fourier spectra with the real diffraction patterns. Previously, by the use of this approach, the real structure of a myosin filament from vertebrate striated muscle has been reconstructed (http://zope.ibib.waw.pl/pspk). In this work, a reconstruction for the thin filament is presented for three states: relaxed, after activation, and during contraction. Good consistency of the calculated Fourier spectra with the real diffraction patterns available in the literature suggests that the thin filament, due to flexibility, plays an active part in muscle contraction, as myosin cross-bridges do.

Organizing to Manage Base-Level Service Contracts in the 1990s.

DTIC Science & Technology

1986-04-01

management of service contracts is the present day organizational structure. The structure is flawed and violates basic principles of management . Until the...are classic principles of management . To state the principle I will quote Ernest Dale: "Authority should be commensurate with responsibility. That is

Structural Changes in Isometrically Contracting Insect Flight Muscle Trapped following a Mechanical Perturbation

PubMed Central

Wu, Shenping; Liu, Jun; Perz-Edwards, Robert J.; Tregear, Richard T.; Winkler, Hanspeter; Franzini-Armstrong, Clara; Sasaki, Hiroyuki; Goldman, Yale E.; Reedy, Michael K.; Taylor, Kenneth A.

2012-01-01

The application of rapidly applied length steps to actively contracting muscle is a classic method for synchronizing the response of myosin cross-bridges so that the average response of the ensemble can be measured. Alternatively, electron tomography (ET) is a technique that can report the structure of the individual members of the ensemble. We probed the structure of active myosin motors (cross-bridges) by applying 0.5% changes in length (either a stretch or a release) within 2 ms to isometrically contracting insect flight muscle (IFM) fibers followed after 5–6 ms by rapid freezing against a liquid helium cooled copper mirror. ET of freeze-substituted fibers, embedded and thin-sectioned, provides 3-D cross-bridge images, sorted by multivariate data analysis into ∼40 classes, distinct in average structure, population size and lattice distribution. Individual actin subunits are resolved facilitating quasi-atomic modeling of each class average to determine its binding strength (weak or strong) to actin. ∼98% of strong-binding acto-myosin attachments present after a length perturbation are confined to “target zones” of only two actin subunits located exactly midway between successive troponin complexes along each long-pitch helical repeat of actin. Significant changes in the types, distribution and structure of actin-myosin attachments occurred in a manner consistent with the mechanical transients. Most dramatic is near disappearance, after either length perturbation, of a class of weak-binding cross-bridges, attached within the target zone, that are highly likely to be precursors of strong-binding cross-bridges. These weak-binding cross-bridges were originally observed in isometrically contracting IFM. Their disappearance following a quick stretch or release can be explained by a recent kinetic model for muscle contraction, as behaviour consistent with their identification as precursors of strong-binding cross-bridges. The results provide a detailed model for contraction in IFM that may be applicable to contraction in other types of muscle. PMID:22761792

48 CFR 1615.404-4 - Profit.

Code of Federal Regulations, 2011 CFR

2011-10-01

... contracts by use of a weighted guidelines structured approach. The service charge so determined will be the... 1615.404-4 Federal Acquisition Regulations System OFFICE OF PERSONNEL MANAGEMENT FEDERAL EMPLOYEES... Contract Pricing 1615.404-4 Profit. (a) When the pricing of FEHB Program contracts is determined by cost...

48 CFR 1615.404-4 - Profit.

Code of Federal Regulations, 2010 CFR

2010-10-01

... contracts by use of a weighted guidelines structured approach. The service charge so determined will be the... 1615.404-4 Federal Acquisition Regulations System OFFICE OF PERSONNEL MANAGEMENT FEDERAL EMPLOYEES... Contract Pricing 1615.404-4 Profit. (a) When the pricing of FEHB Program contracts is determined by cost...

Orogenesis of the Oman Mountains - a new geodynamic model based on structural geology, plate reconstructions and thermochronology

NASA Astrophysics Data System (ADS)

Grobe, Arne; Virgo, Simon; von Hagke, Christoph; Ralf, Littke; Urai, Janos L.

2017-04-01

Ophiolite obduction is an integral part of mountain building in many orogens. However, because the obduction stage is usually overprinted by later tectonic events, obduction geodynamics and its influence on orogenesis are often elusive. The best-preserved ophiolite on Earth is the Semail Ophiolite, Oman Mountains. 350 km of ophiolite and the entire overthrusted margin sequence are exposed perpendicular to the direction of obduction along the northeastern coast of the Sultanate of Oman. Despite excellent exposure, it has been debated whether early stages of obduction included formation of a micro-plate, or if the Oman Mountains result from collision of two macro-plates (e.g. Breton et al., 2004). Furthermore, different tectonic models for the Oman Mountains exist, and it is unclear how structural and tectonic phases relate to geodynamic context. Here we present a multidisciplinary approach to constrain orogenesis of the Oman Mountains. To this end, we first restore the structural evolution of the carbonate platform in the footwall of the Semail ophiolite. Relative ages of nine structural generations can be distinguished, based on more than 1,500 vein and fault overprintings. Top-to-S overthrusting of the Semail ophiolite is witnessed by three different generations of bedding confined veins in an anticlockwise rotating stress field. Rapid burial induced the formation of overpressure cells, and generation and migration of hydrocarbons (Fink et al., 2015; Grobe et al., 2016). Subsequent tectonic thinning of the ophiolite took place above a top-to-NNE crustal scale, ductile shear zone, deforming existing veins and forming a cleavage in clay-rich layers. Ongoing extension formed normal- to oblique-slip faults and horst-graben structures. This was followed by NE-SW oriented ductile shortening, the formation of the Jebel Akhdar anticline, potentially controlled by the positions of the horst-graben structures. Exhumation in the Cenozoic was associated with low angle normal faults on the northern flank of the anticline. We link these results with the geodynamic framework of the area, constrained by plate tectonic reconstructions. Furthermore, we constrain the exhumation history of the mountain belt using zircon (U-Th-Sm)/He dating. Geodynamic and exhumation events can be linked to structural generations. This results in a new tectonic model of the Oman Mountains. We find a remarkable along-strike consistency of mountain building phases and argue involvement of a micro-plate is not required. Breton, J.P., Béchennec, F., Le Métour, J., Moen-Maurel, L., Razin, P., 2004. Eoalpine (Cretaceous) evolution of the Oman Tethyan continental margin: Insights from a structural field study in Jabal Akhdar (Oman Mountains). GeoArabia 9, 41-58. Fink, R., Virgo, S., Arndt, M., Visser, W., Littke, R., Urai, J.L.L., 2015. Solid bitumen in calcite veins from the Natih Formation in the Oman Mountains: Multiple phases of petroleum migration in a changing stress field. Int. J. Coal Geol. 157, 39-51. doi:10.1016/j.coal.2015.07.012 Grobe, A., Urai, J.L.L., Littke, R., Lünsdorf, N.K.K., 2016. Hydrocarbon generation and migration under a large overthrust: The carbonate platform under the Semail Ophiolite, Jebel Akhdar, Oman. Int. J. Coal Geol. 1-17. doi:10.1016/j.coal.2016.02.007

The Structure and Dynamics of the Solar Corona

NASA Technical Reports Server (NTRS)

Mikic, Zoran

2000-01-01

This report covers technical progress during the third year of the NASA Space Physics Theory contract "The Structure and Dynamics of the Solar Corona," between NASA and Science Applications International Corporation, and covers the period June 16, 1998 to August 15, 1999. This is also the final report for this contract. Under this contract SAIC, the University of California, Irvine (UCI), and the Jet Propulsion Laboratory (JPL), have conducted research into theoretical modeling of active regions, the solar corona, and the inner heliosphere, using the MHD model. During the three-year duration of this contract we have published 49 articles in the scientific literature. These publications are listed in Section 3 of this report. In the Appendix we have attached reprints of selected articles. We summarize our progress during the third year of the contract. Full descriptions of our work can be found in the cited publications, a few of which are attached to this report.

The 2.1 Ga old Francevillian biota: biogenicity, taphonomy and biodiversity.

PubMed

El Albani, Abderrazak; Bengtson, Stefan; Canfield, Donald E; Riboulleau, Armelle; Rollion Bard, Claire; Macchiarelli, Roberto; Ngombi Pemba, Lauriss; Hammarlund, Emma; Meunier, Alain; Moubiya Mouele, Idalina; Benzerara, Karim; Bernard, Sylvain; Boulvais, Philippe; Chaussidon, Marc; Cesari, Christian; Fontaine, Claude; Chi-Fru, Ernest; Garcia Ruiz, Juan Manuel; Gauthier-Lafaye, François; Mazurier, Arnaud; Pierson-Wickmann, Anne Catherine; Rouxel, Olivier; Trentesaux, Alain; Vecoli, Marco; Versteegh, Gerard J M; White, Lee; Whitehouse, Martin; Bekker, Andrey

2014-01-01

The Paleoproterozoic Era witnessed crucial steps in the evolution of Earth's surface environments following the first appreciable rise of free atmospheric oxygen concentrations ∼2.3 to 2.1 Ga ago, and concomitant shallow ocean oxygenation. While most sedimentary successions deposited during this time interval have experienced thermal overprinting from burial diagenesis and metamorphism, the ca. 2.1 Ga black shales of the Francevillian B Formation (FB2) cropping out in southeastern Gabon have not. The Francevillian Formation contains centimeter-sized structures interpreted as organized and spatially discrete populations of colonial organisms living in an oxygenated marine ecosystem. Here, new material from the FB2 black shales is presented and analyzed to further explore its biogenicity and taphonomy. Our extended record comprises variably sized, shaped, and structured pyritized macrofossils of lobate, elongated, and rod-shaped morphologies as well as abundant non-pyritized disk-shaped macrofossils and organic-walled acritarchs. Combined microtomography, geochemistry, and sedimentary analysis suggest a biota fossilized during early diagenesis. The emergence of this biota follows a rise in atmospheric oxygen, which is consistent with the idea that surface oxygenation allowed the evolution and ecological expansion of complex megascopic life.

48 CFR 52.236-9 - Protection of Existing Vegetation, Structures, Equipment, Utilities, and Improvements.

Code of Federal Regulations, 2010 CFR

2010-10-01

... preserve and protect all structures, equipment, and vegetation (such as trees, shrubs, and grass) on or... work required under this contract. The Contractor shall only remove trees when specifically authorized... trees are broken during contract performance, or by the careless operation of equipment, or by workmen...

The Influence of Informal Power Structures on School Board-Teacher Union Contract Negotiations.

ERIC Educational Resources Information Center

Miller-Whitehead, Marie

A study examined behaviors of participants trained in a nonadversarial model of contract negotiation, focusing on possible influences of formal and informal power structures, written and unwritten rules, and firmly entrenched adversarial behavior on the bargaining process. Participants were representatives of a district's teacher union and board…

48 CFR 52.236-9 - Protection of Existing Vegetation, Structures, Equipment, Utilities, and Improvements.

Code of Federal Regulations, 2012 CFR

2012-10-01

... preserve and protect all structures, equipment, and vegetation (such as trees, shrubs, and grass) on or... work required under this contract. The Contractor shall only remove trees when specifically authorized... trees are broken during contract performance, or by the careless operation of equipment, or by workmen...

48 CFR 52.236-9 - Protection of Existing Vegetation, Structures, Equipment, Utilities, and Improvements.

Code of Federal Regulations, 2014 CFR

2014-10-01

... preserve and protect all structures, equipment, and vegetation (such as trees, shrubs, and grass) on or... work required under this contract. The Contractor shall only remove trees when specifically authorized... trees are broken during contract performance, or by the careless operation of equipment, or by workmen...

48 CFR 52.236-9 - Protection of Existing Vegetation, Structures, Equipment, Utilities, and Improvements.

Code of Federal Regulations, 2013 CFR

2013-10-01

... preserve and protect all structures, equipment, and vegetation (such as trees, shrubs, and grass) on or... work required under this contract. The Contractor shall only remove trees when specifically authorized... trees are broken during contract performance, or by the careless operation of equipment, or by workmen...

48 CFR 52.236-9 - Protection of Existing Vegetation, Structures, Equipment, Utilities, and Improvements.

Code of Federal Regulations, 2011 CFR

2011-10-01

... preserve and protect all structures, equipment, and vegetation (such as trees, shrubs, and grass) on or... work required under this contract. The Contractor shall only remove trees when specifically authorized... trees are broken during contract performance, or by the careless operation of equipment, or by workmen...

Paleomagnetism of the Late Triassic Hound Island Volcanics: Revisited

USGS Publications Warehouse

Haeussler, Peter J.; Coe, Robert S.; Onstott, T.C.

1992-01-01

The collision and accretion of the Alexander terrane profoundly influenced the geologic history of Alaska and western Canada; however, the terrane's displacement history is only poorly constrained by sparse paleomagnetic studies. We studied the paleomagnetism of the Hound Island Volcanics in order to evaluate the location of the Alexander terrane in Late Triassic time. We collected 618 samples at 102 sites in and near the Keku Strait, Alaska, from the Late Triassic Hound Island Volcanics, the Permian Pybus Formation, and 23-Ma gabbroic intrusions. We found three components of magnetization in the Hound Island Volcanics. The high-temperature component (component A) resides in hematite and magnetite and was found only in highly oxidized lava flows in a geographically restricted area. We think it is primary, or acquired soon after eruption of the lavas, principally because the directions pass a fold test. The paleolatitude indicated by this component (19.2° ± 10.3°) is similar to those determined for various portions of Wrangellia, consistent with the geologic interpretation that the Alexander terrane was with the Wrangellia terrane in Late Triassic time. We found two overprint directions in the Hound Island Volcanics. Component B was acquired 23 m.y. ago due to intrusion of gabbroic dikes and sills. This interpretation is indicated by the similarity of upper-hemisphere directions in the Hound Island Volcanics to those in the gabbro. Component C, found in both the Hound Island Volcanics and the Permian Pybus Formation, is oriented northeast and down, fails a regional fold test, and was acquired after regional deformation around 90 to 100 Ma. This overprint direction yields a paleolatitude similar to, but slightly higher than, slightly older rocks from the Coast Plutonic Complex, suggesting that the Alexander terrane was displaced 17° in early Late Cretaceous time. The occurrence of these two separate overprinting events provides a satisfying explanation of the earlier puzzling results from the Hound Island Volcanics (Hillhouse and Grommé, 1980). Finally, great-circle analysis of the paleomagnetic data from the Pybus Formation suggests the Alexander terrane may have been in the northern hemisphere in Permian time.

Ar-Ar and Rb-Sr dating of very low-/low-grade metamorphism along the main Iapetus suture, Newfoundland

NASA Astrophysics Data System (ADS)

Willner, Arne P.; Glodny, Johannes; Massonne, Hans-Joachim; Romer, Rolf L.; Sudo, Masafumi; Van Staal, Cees R.; Zagorevski, Alexandre

2013-04-01

The Late Ordovician closure of the main tract of Iapetus resulted in juxtaposition of the leading edge of the peri-Gondwanan microplate Ganderia and the composite Laurentian margin. The suture is the Red Indian Line, which separates the Iapetan realm into peri-Gondwanan and peri-Laurentian arc-backarc complexes. The discrete Red Indian Line forms part of a wider collision zone that has a protracted and complicated tectonic history starting with underplating of oceanic terranes beneath the composite margin of Laurentia at ca. 471 Ma during the early stages of the Taconic orogeny. Final collision along the Red Indian Line and closure of the Iapetus ocean occurred at 455 Ma with the underthrusting of the peri-Gondwanan Victoria arc and its Ganderian basement beneath the composite Laurentian margin. The accreted Iapetan realm terranes were progressively deformed during the closure of a remaining Iapetan marginal basin, resulting locally in significant overprint and reactivation during the Silurian (Salinic orogeny). Metamorphic overprint in the deformed Laurentia margin (Notre Dame Zone) above the Red Indian Line is mainly of very low grade to low grade and very heterogeneous. PT-conditions cluster at 3-5 kbar, 300-400°C and 6-7 kbar, 270-330°C. Medium grade conditions are related to local contact metamorphism. Ages of the local peak metamorphism in the peri-Laurentian Iapetan realm were determined by dating white mica with the Ar-Ar system and white mica-bearing assemblages with the Rb-Sr mineral isochron method. Both methods yielded ages that postdate the closure of the main tract of Iapetus. These generally belong to two age ranges: 418-430 Ma (Salinic events) and 350-390 Ma Neoacadian events). Partly two overprints can be detected in one and the same sample. Metamorphism is related to (1) reactivation of deformation in shear zones which partly cause further crustal thickening or strike slip-related deformation, (2) to external fluid influx, (3) to advective heating by synkinematic intrusions or (4) to a combination of these effects. Salinic to Neoacadian postcollisional processes in the collision zone apparently are much more widespread than formerly recognized.

Dronning Maud Lands (East Antarctica) significance for Late Mesoproterozoic/Early Neoproterozoic supercontinent reconstructions

NASA Astrophysics Data System (ADS)

Jacobs, Joachim; Elburg, Marlina; Laeufer, Andreas; Kleinhanns, Ilka C.; Henjes-Kunst, Friedhelm; Estrada, Solveig; Ruppel, Antonia; Damaske, Detlef; Montero, Pilar; Bea, Fernando

2015-04-01

The recent study of a so far white spot on the geological map of Dronning Maud Land (DML) during the international GEA expeditions sheds new light on the significance of major tectono-metamorphic provinces of Dronning Maud Land, East Antarctica. The western part of eastern DML allows the characterization and ground-truthing of a large and mostly ice-covered area, that is geophysically distinct and which was previously interpreted as a potentially older cratonic block south of a Late Neoproterozoic/EarlyPaleozoic mobile belt, which is exposed in the Sør Rondane Mts. (SRM). SHRIMP/SIMS zircon analyses of 20 samples together with new geochemistry indicate that the exposed basement consists of a ca. 1000-900 Ma juvenile terrane that is very similar to the juvenile rocks of the SW-Terrane of the SRM, a characteristic gabbro-trondhjemite-tonalite-granite suite. However, in contrast to the southern part of the SW-Terrane, our study area shows intense crustal reworking at medium to high-grade conditions between ca. 630-520 Ma, associated with significant felsic melt production, including A-type granitoid magmatism. Therefore, the study area, and thereby the aeromagnetically distinct SE DML province does neither represent the foreland of a Late Neoproterozoic/EarlyPaleozoic mobile belt, nor a craton, as has previously been speculated. It more likely represents the westward continuation of Rayner-age crust (1000-900 Ma) that has undergone additional protracted LN/EP overprinting. We interpret the southern part of the only weakly overprinted SW-Terrane as a mega-boudin within a broad, rheologically weaker, NW-SE trending LN/EP mobile belt. Rayner-type crust likely continues further west, where it abuts along the SW-trending Forster Magnetic Anomaly. The latter is interpreted as a suture, which separates typical Grenville-age crust of the Maud Belt to the W from Rayner-age crust to the E. The study area has therefore clearly Indian affinities. Its juvenile character with a lack of metamorphic overprint at the end of crust formation could point to an accretionary history along this part of the Indian segment of Rodinia, immediately following final Rodinia assembly.

Geochronology of high-grade metamorphic rocks from the Anjul area, Lut block, eastern Iran

NASA Astrophysics Data System (ADS)

Bröcker, Michael; Fotoohi Rad, Gholamreza; Abbaslu, Fateme; Rodionov, Nikolay

2014-03-01

U-Pb and Rb-Sr geochronology has been used to constrain robust ages for leucosomes and high-grade gneisses from the Anjul area in the eastern part of the Lut block, Iran. The new results do not support the previously suggested Proterozoic age for this occurrence, but instead reveal the importance of Jurassic and Cretaceous magmatic and/or metamorphic processes. Ionprobe U-Pb zircon dating yielded four age groups (>200, ˜168, ˜120 and ˜110 Ma). Textural observations suggest that ages >200 Ma represent inherited zircons. The majority of zircons yielded Jurassic (168 ± 2 and 169 ± 2 Ma) and Cretaceous (120 ± 3, 108 ± 2, 111 ± 3 Ma) intercept ages. Explanations for the two dominant age groups (˜168 and ˜110 Ma) include the following alternatives: (a) the Jurassic ages constrain the protolith age of magmatic precursors that experienced metamorphic overprinting at ˜110 Ma; and (b) both the ˜168 Ma and ˜110 Ma ages indicate the time of metamorphic episodes, e.g. zircon-formation during different anatectic events or migmatization followed by a lower temperature overprint associated with new zircon growth. Multi-point Rb-Sr mineral isochrons of three additional gneisses indicated ages of 102 ± 3 Ma, 102 ± 1 Ma and 97 ± 2 Ma. These ages further document the importance of Cretaceous metamorphism in the Anjul area. The difference compared to the U-Pb ages of zircon overgrowths is interpreted to indicate cooling after a thermal event with or without partial melting. The two major occurrences of metamorphic rocks in the eastern Lut block are exposed in the Deh-Salm and the Anjul region. These occurrences may represent two different segments of a single metamorphic belt that can broadly be related to accretionary and/or collisional processes induced by convergence between the Afro-Arabian and Eurasian plates. Our geochronological study provides a conclusive evidence for Cretaceous metamorphism. We speculate that zircon overgrowths with Cretaceous ages reflect metamorphic processes unrelated to melt formation that overprinted a pre-existing population recording Jurassic anatexis.

Felsic granulite with layers of eclogite facies rocks in the Bohemian Massif; did they share a common metamorphic history?

NASA Astrophysics Data System (ADS)

Jedlicka, Radim; Faryad, Shah Wali

2017-08-01

High pressure granulite and granulite gneiss from the Rychleby Mountains in the East Sudetes form an approximately 7 km long and 0.8 km wide body, which is enclosed by amphibolite facies orthogneiss with a steep foliation. Well preserved felsic granulite is located in the central part of the body, where several small bodies of mafic granulite are also present. In comparison to other high pressure granulites in the Bohemian Massif, which show strong mineral and textural re-equilibration under granulite facies conditions, the mafic granulite samples preserve eclogite facies minerals (garnet, omphacite, kyanite, rutile and phengite) and their field and textural relations indicate that both mafic and felsic granulites shared common metamorphic history during prograde eclogite facies and subsequent granulite facies events. Garnet from both granulite varieties shows prograde compositional zoning and contains inclusions of phengite. Yttrium and REEs in garnet show typical bell-shaped distributions with no annular peaks near the grain rims. Investigation of major and trace elements zoning, including REEs distribution in garnet, was combined with thermodynamic modelling to constrain the early eclogite facies metamorphism and to estimate pressure-temperature conditions of the subsequent granulite facies overprint. The first (U)HP metamorphism occurred along a low geothermal gradient in a subduction-related environment from its initial stage at 0.8 GPa/460 °C and reached pressures up to 2.5 GPa at 550 °C. The subsequent granulite facies overprint (1.6-1.8 GPa/800-880 °C) affected the rocks only partially; by replacement of omphacite into diopside + plagioclase symplectite and by compositional modification of garnet rims. The mineral textures and the preservation of the eclogite facies prograde compositional zoning in garnet cores confirm that the granulite facies overprint was either too short or too faint to cause recrystallisation and homogenisation of the eclogite facies mineral assemblage. The results of this study are compared with other granulite massifs in the Moldanubian Zone. In addition, a possible scenario for the Variscan eclogite and subsequent granulite facies metamorphism in the Bohemian Massif is discussed.

Tectonics of the Qinling (Central China): Tectonostratigraphy, geochronology, and deformation history

USGS Publications Warehouse

Ratschbacher, L.; Hacker, B.R.; Calvert, A.; Webb, L.E.; Grimmer, J.C.; McWilliams, M.O.; Ireland, T.; Dong, S.; Hu, Jiawen

2003-01-01

The Qinling orogen preserves a record of late mid-Proterozoic to Cenozoic tectonism in central China. High-pressure metamorphism and ophiolite emplacement (Songshugou ophiolite) assembled the Yangtze craton, including the lower Qinling unit, into Rodinia during the ~1.0 Ga Grenvillian orogeny. The lower Qinling unit then rifted from the Yangtze craton at ~0.7 Ga. Subsequent intra-oceanic arc formation at ~470-490 Ma was followed by accretion of the lower Qinling unit first to the intra-oceanic arc and then to the Sino-Korea craton. Subduction then imprinted a ~400 Ma Andean-type magmatic arc onto all units north of the northern Liuling unit. Oblique subduction created Silurian-Devonian WNW-trending, sinistral transpressive wrench zones (e.g., Lo-Nan, Shang-Dan), and Late Permian-Early Triassic subduction reactivated them in dextral transpression (Lo-Nan, Shang-Xiang, Shang-Dan) and subducted the northern edge of the Yangtze craton. Exhumation of the cratonal edge formed the Wudang metamorphic core complex during dominantly pure shear crustal extension at ~230-235 Ma. Post-collisional south-directed shortening continued through the Early Jurassic. Cretaceous reactivation of the Qinling orogen started with NW-SE sinistral transtension, coeval with large-scale Early Cretaceous crustal extension and sinistral transtension in the northern Dabie Shan; it presumably resulted from the combined effects of the Siberia-Mongolia-Sino-Korean and Lhasa-West Burma-Qiangtang-Indochina collisions and Pacific subduction. Regional dextral wrenching was active within a NE-SW extensional regime between ~60 and 100 Ma. An Early Cretaceous Andean-type continental magmatic arc, with widespread Early Cretaceous magmatism and back-arc extension, was overprinted by shortening related to the collision of Yangtze-Indochina Block with the West Philippines Block. Strike-slip and normal faults associated with Eocene half-graben basins record Paleogene NNE-SSW contraction and WNW-ESE extension. The Neogene(?) is characterized by normal faults and NNE-trending sub-horizontal extension. Pleistocene(?)-Quaternary NW-SE extension and NE-SW contraction comprises sinistral strike-slip faults and is part of the NW-SE extension imposed across eastern Asia by the India-Asia collision. 

Some Contracting Controls at Mission and Installation Contracting Command, Fort Polk, Louisiana, Need Improvement

DTIC Science & Technology

2015-02-12

erosion control. Work that did not meet PWS requirements included laying pavement stones for a monument walkway and installing a glossy marble -like... property structures, roads, training areas, training facilities, and utility infrastructure. The contract period of performance consisted of a base year

Raising the Curtain: Exploring Dancers’ Perceptions of Obligation through the Psychological Contract Lens

ERIC Educational Resources Information Center

Stanway, Alicia R.; Bordia, Sarbari; Fein, Erich C.

2013-01-01

The current study takes an exploratory approach to investigate which situational factors influence perceptions of psychological contracts, as well as the content that comprises psychological contracts in the dance training industry. Semi-structured interviews ("n"?=?10) were conducted with students enrolled in a higher education…

Lack of symmetry in employees' perceptions of the psychological contract.

PubMed

Jepsen, Denise M; Rodwell, John J

2012-06-01

Despite debate on the nature of employees' perceptions of their psychological contract, little research has compared employees' and employers' sides of the psychological contract. All 80 items from both scales in the Psychological Contract Inventory were used in a survey of 436 currently working, non-student respondents. Structural equation modeling yielded nonsymmetrical perspectives on promises and obligations, highlighting the validity of approaching the issues via individual perceptions.

75 FR 41097 - Homeland Security Acquisition Regulation; Lead System Integrators [HSAR Case 2009-003

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-15

... contract type and fee structure based on risks inherent in the work to be performed, in accordance with... competitive procedures, DHS takes appropriate steps to prevent any organizational conflicts of interest in the... specification of various types of contracts and fee structures that are appropriate for use with lead system...

Method and apparatus for preloading a joint by remotely operable means

NASA Technical Reports Server (NTRS)

Kahn, Jon B. (Inventor)

1993-01-01

The invention is a method and apparatus for joining structures, an active structure and a passive structure, and imposing a tensile pre-load on the joint by a remotely operable mechanism comprising a heat contractible joining element. The method and apparatus include mounting on the structure, a probe shaft of material which is transformable from an expanded length to a contracted length when heated to a specific temperature range. The shaft is provided with a probe head which is receivable in a receptacle opening formed in the passive structure, when the active structure is moved into engagement therewith by an appropriate manipulator mechanism. A latching system mounted on the structure adjacent to the receptacle opening captures the probe head, when the probe head is inserted a predetermined amount. A heating coil on the shaft is energizable by remote control for heating the shaft to a temperature range which transforms the shaft to its contracted length, whereby a latching shoulder thereof engages latching elements of the latching system and imposes a tensile preload on the structural joint. Provision is also made for manually adjusting the probe head on the shaft to allow for manual detachment of the structures or manual preloading of the structural joint.

Method and apparatus for preloading a joint by remotely operable means

NASA Technical Reports Server (NTRS)

Shelton, Robert O. (Inventor)

1992-01-01

The invention is a method and apparatus for joining structures, an active structure and a passive structure, and imposing a tensile pre-load on the joint by a remotely operable mechanism comprising a heat contractible joining element. The method and apparatus include mounting on the structure, a probe shaft of material which is transformable from an expanded length to a contracted length when heated to a specific temperature range. The shaft is provided with a probe head which is receivable in a receptacle opening formed in the passive structure, when the active structure is moved into engagement therewith by an appropriate manipulator mechanism. A latching system mounted on the structure adjacent to the receptacle opening captures the probe head, when the probe head is inserted a predetermined amount. A heating coil on the shaft is energizable by remote control for heating the shaft to a temperature range which transforms the shaft to its contracted length, whereby a latching shoulder thereof engages latching elements of the latching system and imposes a tensile preload on the structural joint. Provision is also made for manually adjusting the probe head on the shaft to allow for manual detachment of the structures or manual preloading of the structural joint.

Tectonic elements of the continental margin of East Antarctica, 38-164ºE

USGS Publications Warehouse

O'Brien, P.E.; Stagg, H.M.J.

2007-01-01

The East Antarctic continental margin from 38–164ºE is divided into western and eastern provinces that developed during the separation of India from Australia–Antarctica (Early Cretaceous) and Australia from Antarctica (Late Cretaceous). In the overlap between these provinces the geology is complex and bears the imprint of both extension/spreading episodes, with an overprinting of volcanism. The main rift-bounding faults appear to approximately coincide with the outer edge of the continental shelf. Inboard of these faults, the sedimentary cover thins above shallowing basement towards the coast where crystalline basement generally crops out. The continental slope and the landward flanks of the ocean basins, are blanketed by up to 9–10 km of mainly post-rift sediments in margin-parallel basins, except in the Bruce Rise area. Beneath this blanket, extensive rift basins are identified off Enderby and Wilkes Land/Terre Adélie; however, their extent and detailed structures are difficult to determine.

Metamorphozed Hercynian granitoids in the Alpine structures of the Central Rhodope, Bulgaria: geotectonic position and geochemistry

NASA Astrophysics Data System (ADS)

Cherneva, Zlatka; Georgieva, Milena

2005-05-01

Orthogneisses of late-Hercynian protolith age crop out in the Central Rhodope high-grade metamorphic complex, which is part of the Alpine orogen in south-eastern Europe. They compose a tectonic unit bordered by late-Alpine extensional shear zones. These rocks reflect Eocene amphibolite facies migmatization (<750 °C/0.9-0.5 GPa). The low-temperature melting favored zircon inheritance and disturbed mainly the LILE protolith compositions. Despite the intense Alpine metamorphic overprint, the major elements, HFSE and REE reflect the initial composition of the Hercynian protolith. A geochemical data set summarizing 200 whole rock analyses testifies to a calc-alkaline magma differentiation producing a compositional range of tonalite and/or granodiorite to granite and leucocratic granite. Geochemical compositions combined with published isotope and age data suggest dominant I-type protoliths and mixed magma sources including crustal and mantle material, and distinguish between older granitoids of volcanic-arc affinity and probably younger ones of late or post-collision origin.

REE compositions in fossil vertebrate dental tissues indicate biomineral preservation

NASA Astrophysics Data System (ADS)

Žigaite, Ž.; Kear, B.; Pérez-Huerta, A.; Jeffries, T.; Blom, H.

2012-04-01

Rare earth element (REE) abundances have been measured in a number of Palaeozoic and Mesozoic dental tissues using Laser Ablation Inductively Coupled Plasma Mass-spectrometry (LA-ICP-MS). Fossil vertebrates analysed comprise scales and tesserae of Silurian and Devonian acanthodians, chondrichthyans, galeaspids, mongolepids, thelodonts, as well as teeth of Cretaceous lungfish and marine reptiles. The evaluation of fossil preservation level has been made by semi-quantitative spot geochemistry analyses on fine polished teeth and scale thin sections, using Energy Dispersive X-ray Spectroscopy (EDS). Fossil teeth and scales with significant structure and colour alteration have shown elevated heavy element concentrations, and the silicification of bioapatite has been common in their tissues. Stable oxygen isotope measurements (δ18O) of bulk biomineral have been conducted in parallel, and showed comparatively lower heavy oxygen values in the same fossil tissues with stronger visible alteration. Significant difference in REE concentrations has been observed between the dentine and enamel of Cretaceous plesiosaurs, suggesting the enamel to be more geochemically resistant to diagenetic overprint.

Structural analysis of the Gachsar sub-zone in central Alborz range; constrain for inversion tectonics followed by the range transverse faulting

NASA Astrophysics Data System (ADS)

Yassaghi, A.; Naeimi, A.

2011-08-01

Analysis of the Gachsar structural sub-zone has been carried out to constrain structural evolution of the central Alborz range situated in the central Alpine Himalayan orogenic system. The sub-zone bounded by the northward-dipping Kandovan Fault to the north and the southward-dipping Taleghan Fault to the south is transversely cut by several sinistral faults. The Kandovan Fault that controls development of the Eocene rocks in its footwall from the Paleozoic-Mesozoic units in the fault hanging wall is interpreted as an inverted basin-bounding fault. Structural evidences include the presence of a thin-skinned imbricate thrust system propagated from a detachment zone that acts as a footwall shortcut thrust, development of large synclines in the fault footwall as well as back thrusts and pop-up structures on the fault hanging wall. Kinematics of the inverted Kandovan Fault and its accompanying structures constrain the N-S shortening direction proposed for the Alborz range until Late Miocene. The transverse sinistral faults that are in acute angle of 15° to a major magnetic lineament, which represents a basement fault, are interpreted to develop as synthetic Riedel shears on the cover sequences during reactivation of the basement fault. This overprinting of the transverse faults on the earlier inverted extensional fault occurs since the Late Miocene when the south Caspian basin block attained a SSW movement relative to the central Iran. Therefore, recent deformation in the range is a result of the basement transverse-fault reactivation.

Relation between alternating open/closed-conduit conditions and deformation patterns: An example from the Somma-Vesuvius volcano (southern Italy)

NASA Astrophysics Data System (ADS)

Tramparulo, F. D. A.; Vitale, S.; Isaia, R.; Tadini, A.; Bisson, M.; Prinzi, E. P.

2018-07-01

We present the results of a meso-scale systematic structural analysis of fractures, faults and dykes exposed at the Somma-Vesuvius volcano (southern Italy). Observed fractures include: (i) radial and tangential (with respect the caldera axis), sub-metric to metric joints associated with the edifice load and volcano-tectonic activity (i.e. inflation, deflation and caldera collapse stages) and (ii) decameter-scale fractures related to volcano flank instabilities. For the Somma-Vesuvius volcano, preexisting radial joints were commonly reactivated as transfer faults during the caldera formation, allowing different blocks to move toward the center of the collapsing area. Dykes occur with different geometries, including en-echelon structures bounding structural depressions. The orientation analysis of all structures indicates that they are preferentially oriented. Furthermore, we provide a morphological lineament analysis using high-resolution Digital Terrain Models of Somma-Vesuvius. Azimuth and spatial distribution of dykes and morphological lineaments were analyzed for comparison with the old Somma Crater and Gran Cono axes, respectively. Results highlight the overprinting of radial and clustered strain patterns recorded in different volcano-tectonic evolution stages. We suggest a possible deformation evolution model in which structures develop along either radial or preferential trends, highlighting different volcanic conditions: (i) where radial patterns occur, the structures developed during volcanic inflation cycles with a closed magmatic conduit condition whereas (ii) clustered patterns are probably associated with a regional strain field that overcomes the local deformation field, a situation typical in the case of open-conduit activity.

Taphonomy and paleoecology of nonmarine mollusca: indicators of alluvial plain lacustrine sedimentation, upper part of the Tongue River Member, Fort Union Formation ( Paleocene), Northern Powder River Basin, Wyoming and Montana ( USA).

USGS Publications Warehouse

Hanley, J.H.; Flores, R.M.

1987-01-01

The composition, species abundances, and spatial and temporal distributions of mollusc assemblages were controlled by the environments in which they lived and the depositional processes that affected the molluscs after death and before final burial. Post-mortem transport, reworking and concentration of shells, and mixing of faunal elements from discrete habitats produced a taphonomic 'overprint' on assemblage characteristics that directly reflects the processes of alluvial plain and floodbasin lacustrine sedimentation. The 'overprint' can be interpreted from outcrop analysis of molluscan biofabric, which consists of: 1) orientation, fragmentation, size-sorting, abrasion, density, and dispersion of shells, 2) the nature and extent of shell-infilling, and 3) ratio of articulated to disarticulated bivalves. Taphonomic characteristics were used with sedimentological properties to differentiate in-place, reworked, transported, and ecologically mixed mollusc assemblages. This study also defines the paleoecology of habitat preferences of mollusc species as a basis for recognition of the environments in which these assemblages were deposited: 1) large floodbasin lakes, 2) small floodbasin lakes, and 3) crevasse deltas and splays. Integration of sedimentology and paleoecology provides an interdisciplinary approach to the interpretation of alluvial environments through time in the Tongue River Member. -Authors

Tectonics and geology of spreading ridge subduction at the Chile Triple Junction: a synthesis of results from Leg 141 of the Ocean Drilling Program

USGS Publications Warehouse

Behrmann, J.H.; Lewis, S.D.; Cande, S.C.

1994-01-01

An active oceanic spreading ridge is being subducted beneath the South American continent at the Chile Triple Junction. This process has played a major part in the evolution of most of the continental margins that border the Pacific Ocean basin. A combination of high resolution swath bathymetric maps, seismic reflection profiles and drillhole and core data from five sites drilled during Ocean Drilling Program (ODP) Leg 141 provide important data that define the tectonic, structural and stratigraphic effects of this modern example of spreading ridge subduction. A change from subduction accretion to subduction erosion occurs along-strike of the South American forearc. This change is prominently expressed by normal faulting, forearc subsidence, oversteepening of topographic slopes and intensive sedimentary mass wasting, overprinted on older signatures of sediment accretion, overthrusting and uplift processes in the forearc. Data from drill sites north of the triple junction (Sites 859-861) show that after an important phase of forearc building in the early to late Pliocene, subduction accretion had ceased in the late Pliocene. Since that time sediment on the downgoing oceanic Nazca plate has been subducted. Site 863 was drilled into the forearc in the immediate vicinity of the triple junction above the subducted spreading ridge axis. Here, thick and intensely folded and faulted trench slope sediments of Pleistocene age are currently involved in the frontal deformation of the forearc. Early faults with thrust and reverse kinematics are overprinted by later normal faults. The Chile Triple Junction is also the site of apparent ophiolite emplacement into the South American forearc. Drilling at Site 862 on the Taitao Ridge revealed an offshore volcanic sequence of Plio-Pleistocene age associated with the Taitao Fracture Zone, adjacent to exposures of the Pliocene-aged Taitao ophiolite onshore. Despite the large-scale loss of material from the forearc at the triple junction, ophiolite emplacement produces a large topographic promontory in the forearc immediately after ridge subduction, and represents the first stage of forearc rebuilding. ?? 1994 Springer-Verlag.

Telescoping metamorphic isograds: Evidence from 40Ar/39A dating in the Orange-Milford belt, southern Connecticut

USGS Publications Warehouse

Kunk, Michael J.; Walsh, Gregory J.; Growdon, Martha L.; Wintsch, Robert P.

2013-01-01

New 40Ar/39Ar ages for hornblende and muscovite from the Orange-Milford belt in southern Connecticut reflect cooling from Acadian amphibolite facies metamorphism between ∼380 to 360 Ma followed by retrograde recrystallization of fabric-forming muscovite and chlorite during lower greenschist facies Alleghanian transpression at ∼280 Ma. Reported field temperature and pressure gradients are improbably high for these rocks and a NW metamorphic field gradient climbing from chlorite-grade to staurolite-grade occurs over less than 5 km. Simple tilting cannot account for this compressed isograd spacing given the geothermal gradient of ∼20 °C/km present at the time of regional metamorphism. However, post-metamorphic transpression could effectively telescope the isograds by stretching the belt at an oblique angle to the isograd traces. Textures in the field and in thin section reveal several older prograde schistosities overprinted by lower greenschist facies fabrics. The late cleavages commonly occur at the scale of ∼100 μm and these samples contain multiple age populations of white mica. 40Ar/39Ar analysis of these poly-metamorphic samples with mixed muscovite populations yield climbing or U-shaped age spectra. The ages of the low temperature steps are late Paleozoic, while the ages of the older steps are late Devonian. These results support our petrologic interpretation that the younger cleavage developed under metamorphic conditions below the closure temperature for Ar diffusion in muscovite, that is, in the lower greenschist facies. The correlation of a younger regionally reproducible age population with a pervasive retrograde muscovite ± chlorite cleavage reveals an Alleghanian (∼280 Ma) overprint on the Acadian metamorphic gradient (∼380 Ma). Outcrop-scale structures including drag folds and imbricate boudins suggest that Alleghanian deformation and cleavage development occurred in response to dextral transpression along a northeast striking boundary. Alleghanian oblique collision of accreting terranes from the northeast would have resulted in northeast-southwest dextral transpression against the New York promontory. This deformation was responsible for crystallization of pervasive retrograde muscovite + chlorite cleavages and associated telescoping of the Acadian metamorphic isograds in southern Connecticut at ∼280 Ma.

Historical extreme wave and landslide deposits on the Shirasuka coastal lowlands, Shizuoka Prefecture, Japan

NASA Astrophysics Data System (ADS)

Garrett, Ed; Riedesel, Svenja; Fujiwara, Osamu; Walstra, Jan; Deforce, Koen; Yokoyama, Yusuke; Schmidt, Sabine; Brill, Dominik; Roberts, Helen; Duller, Geoff; Brückner, Hulmut; De Batist, Marc; Heyvaert, Vanessa

2017-04-01

Future megathrust earthquakes and consequential tsunamis pose exceptional hazards to densely populated and highly industrialised coastlines facing the Nankai-Suruga Trough, south central Japan. Geological investigations of coastal sedimentary sequences play a key role in understanding megathrust behaviour and developing seismic and tsunami hazard assessments. In this study, we revisit a previously published palaeoseismic site at Shirasuka, located on the Enshu-nada coastline of Shizuoka Prefecture, seeking both to provide further information on past earthquakes and tsunamis and to explore the prospects and limitations of geological data with respect to assessing seismic and tsunami hazards. At Shirasuka, six closely-spaced vibrocores reveal four sand layers interbedded with organic muds. Photographs, X-ray CT scans and grain size analysis reveal a variety of sedimentary structures within these layers, including abrupt contacts, massive sands, rip-up clasts, internal mud drapes and cross bedding. Microfossil assemblages (diatoms, pollen, non-pollen palynomorphs) and optically stimulated luminescence overdispersion values of single grain feldspars highlight varying sediment sources and transport mechanisms. We suggest that the uppermost sand layer records a landslide from the landward margin of the site, while the remaining three sand layers reflect at least four extreme wave events, some of which are overprinted. We refine the published chronology using AMS radiocarbon, radionuclide and infrared stimulated luminescence approaches. Our Bayesian age models suggest that the oldest two sand layers relate to historically documented tsunamis in AD 1361 and 1498. The second youngest sand layer provides ages consistent with tsunamis in AD 1605 and 1707 and potentially also storm surges in 1680 and/or 1699. The modelled age of the landslide sand layer is consistent with the AD 1944 earthquake. The presence of a fresh scarp in US military aerial photographs from 1947 and revegetation by 1959 is also consistent with possible coseismic triggering of this landslide. Difficulties in correlating sand layers between cores, the identification of overprinting of evidence and the lack of prehistoric deposits exemplify ongoing issues in the search for palaeotsunami deposits along the Nankai-Suruga Trough. The identification of a subaerial mass movement deposit as possible evidence for coseismic shaking provides a potentially complementary palaeoseismic approach and an area for further investigation.

Evolution of the blueschist and greenschist facies rocks of Sifnos, Cyclades, Greece

NASA Astrophysics Data System (ADS)

Matthews, Alan; Schliestedt, Manfred

1984-11-01

The metamorphism on the island of Sifnos is characterized by the Eocene development of a coherent highpressure blueschist terrane and an early Miocene greenschist facies overprint. This study documents the metamorphic evolution of the blueschist assemblages, still preserved in the northern parts of the island, and their subsequent transformation into greenschists in the central and southern parts. The oxygen isotope geothermometry is based on calibrations for quartz, pyroxenes and magnetite (Matthews et al. 1983a) augmented by revised calibrations for the minerals muscovite ( Δ Qz-Mu=1.55×106 T -2), epidote ( δ Qz-Ep= 1.56+1.92 Δ ps)106 T -2), and rutile ( Δ Qz-Ru=4.54×106 T -2). Oxygen isotope analyses of minerals from the Blueschist unit of northern Sifnos give consistent fractionations which are independent of rock type. An average temperature of 455° C was obtained, although the scatter in temperatures deduced from the various geothermometers suggests that equilibration occurs under slightly changing physicochemical conditions. Analyses of minerals and whole rocks shows that pervasive equilibration in the presence of a common metamorphic fluid has not occurred. The minerals and whole rocks of the greenschists of central Sifnos are systematically enriched in 18O relative to the blueschist assemblages. Chemical data indicate that the greenschist overprint was accompanied by a metasomatic enrichment of Ca2+ and CO2. The petrologic, isotopic and chemical evidence favour a metamorphism governed by the infiltration of 18O-CO2 enriched aqueous solutions. It is reasonable to assume that this is connected with the Miocene magmatic activity observed throughout the Cyclades. The marbles separating the Blueschist from the Greenschist unit probably acted as barriers to fluid infiltration into the blueschists and were responsible for their preservation. The pressure of the blueschist metamorphism is estimated at 14±2 kbar, corresponding to a depth of ca. 50 km. The structural style and stratigraphy of Sifnos are suggestive of the subduction of a continental margin sequence. It is clear that the considerable tectonic depression may be associated with continental collision and underthrusting.

U-Th-PbT Monazite Gechronology in the South Carpathian Basement: Variscan Syn-Metamorphic Tectonic Stacking and Long-Lasting Post-Peak Decompressional Overprints

NASA Astrophysics Data System (ADS)

Săbău, G.; Negulescu, E.

2012-12-01

Dating metamorphic events appears to be unsatisfactorily addressed by most of the widely-employed and otherwise accurate and productive isotopic techniques, because the phases and systems investigated do not directly relate to the metamorphic events themselves. An adequate answer to this challenge is instead provided by microprobe-assisted chemical U-Th-PbT monazite geochronology, by its spatial resolution, truly in situ character and the possibility to reference analyses against well-defined textural environments and features, as well as a qualitative timeframe derived therefrom. Though chemical U-Th-PbT monazite geochronology is increasingly applied to seek answers ranging form a general characterization to fine details of the thermotectonic evolution of magmatic and metamorphic rocks, there are so far, unlike in the case of isotopic geochronological methods, no clearly defined standard analytical and data processing protocols. Two main reasons for this have to be mentioned, namely that chemical U-Th-PbT chronology is actually a proxy for isotopic geochronology, and the quantification of the errors and their propagation cannot be directly assessed because apparent ages are related to the measured element concentrations by an implicit function, the law of radioactive decay. Current approaches rely on treating calculated individual age values as primary data, a priori grouping of analyses supposed (and subsequently tested) to be coeval, and their statistical processing in order to obtain age values. An alternative approach we applied in basement units of the South Carpathians consists in an explicit approximation of the age formula and associated errors propagated from element concentrations to age values, and individual treatment of each age datum. The separation of the age clusters from the overall age spectrum of each sample was operated by tracing the variations of the normalized age gradient on the age spectrum sorted by increasing age values, and fine-tuned by comparison with the general probability function calculated from all individual age and error values. Monazite chemical compositions and variations, in connection with the textural and zonal setting of the analyzed spots, were used to estimate the geological relevance of the derived age clusters, along with inter-sample comparisons anchored on granitoid samples displaying well-expressed age plateaus, conspicuously related to consolidation and emplacement ages. The resultant ages are consistent with sandwiching of juvenile Variscan metamorphic units and slivers of reworked older basement fragments in structurally coherent sequences, formed by syn/late-metamorphic tectonic stacking. Differential exhumation and ensuing areal or local lower pressure overprinting initiated in early Permian lasted up until the Late Jurassic. The age distribution of the pervasive metamorphic overprints, in consistency with the variation of the metamorphic conditions recorded, requires a partial revision and an iterative adjustment between determined ages and metamorphic features, and the lithostratigraphic separations operated in several basement units of the South Carpathians. Acknowledgements Grant PN-II-ID-PCE-2011-3-0030 by the Romanian Executive Unit for Financing Higher Education, Research, Development and Innovation (UEFISCDI)

How steep are the Alps?

NASA Astrophysics Data System (ADS)

Robl, Jörg; Prasicek, Günther; Stüwe, Kurt; Hergarten, Stefan

2014-05-01

The topography of the European Alps reflects continental collision, crustal thickening and buoyancy driven surface uplift, overprinted by erosional processes. Topographic gradients generally steepen from the valley floors up to about 1500 m - 2000 m followed by an unexpected decrease in slope up to about 2900 m and a further increase to the highest summits of the range. Several studies have interpreted this pattern and the accompanied maximum in the hypsometric curve in terms of either the critical slope stability angle, the prematurity of the Alps caused by recent tectonic uplift, or the effect of the glacial "buzz saw" related to the Pleistocene glaciation cycles. There is consensus that the lithological inventory represents a first order parameter for the steepness of fluvial channels and the angle of hillslopes in steady state and that the response time of a transient landscape is controlled by lithology. In this study we systematically explore the slope-elevation distributions for several hundred continuous domains of the major structural units of the Alps. For this, we apply a novel numerical code to determine the predominant cause for the observed peculiar topography. We compare adjacent alpine domains with contrasting lithology to explore lithological effects on the limiting slope stability angle. We analyze domains with different lithology in the non-glaciated parts of the orogen to highlight the state of maturity related to a recent uplift event. We evaluate the glacial effects on the landscape by the comparison of areas belonging to the same structural units but affected by a variable amount of glacial imprint. The results show that lithology has a major impact on the morphometric characteristics of the European Alps. Adjacent but different structural units show a significant variability in their slope-elevation distributions although they have experienced the same uplift history and the same amount of glacial imprint. This suggests that the response time and process rates in transient landscapes are predominantly governed by the lithological inventory. Areas belonging to the same structural unit show similar characteristics in the slope-elevation distribution independent from their spatial position within the orogen (e.g. external massifs). These similarities are probably caused by the vertical position of the Pleistocene equilibrium line altitude - an observation well in line with the glacial "buzz saw" hypothesis. However, several non-glaciated regions at the eastern and south-western border of the Alps show a slope-elevation relation similar to formerly glaciated domains. However, in contrast to the glaciated realm, the inflection point in the slope-elevation distribution is located at various elevation levels and is consistent with a reported recent pulse of uplift with spatial and/or temporal variations in uplift rate and initiation. Therefore, we interpret the slope-elevation distribution of the European Alps to be mainly caused by glacial erosion. The morphological record of a recent uplift event in the Alps has probably been overprinted by Pleistocene glaciations and may therefore only be detectable in non-glaciated regions of the peripheral parts of the Alps and in subsurface structures.

Function and structure in early modern muscular mechanics. Four episodes and a dialogue between Stensen and Borelli on two chief muscular systems.

PubMed

Kardel, T

1997-01-01

The dispute on the movement of skeletal muscles in 1667 between Giovanni Alfonso Borelli, who maintained the ancient movement caused by inflation theory, and Niels Stensen (Nicolaus Steno), who proposed the first recorded theory of fibre contraction, had far reaching implications for understanding the relation between muscle morphology and function. A dialogue is reconstructed from citations from the two authors' main works. They had a similar dispute on the movement of the heart along the lines of the debate in the 1630s between William Harvey favouring contraction and René Descartes favouring swelling. Evidence is provided for the delayed general acceptance of fibre contraction in both heart and skeletal muscles. It is shown that the inflation interpretation of muscular mechanics elaborated by Borelli, Johann Bernoulli, his son Daniel, and by others, was maintained from ancient authors and Descartes in part due to a conceptual block resulting from the mechanical philosophy that denied any force of attraction in nature. The alternative theory, that of fibre contraction, was thought of as self-motion, which violated an accepted mechanical principle and therefore was rejected. In the mid-18th century, Albrecht von Haller recorded no microscopic structures in support of inflation. He adopted the view that contraction in fibres of muscles is generated through an 'irritability'. Research on this entity has taken place ever since with a clear preponderance of studies on single fibre properties and subcellular structures. Haller did not, however, refer to the original contribution of Stensen on fibre contraction. Haller even rejected Stensen's functional architecture of skeletal muscle. This structure, now called the unipennate, or semipennate, actuator, was overlooked and had to await confirmation by anatomical rediscovery and pragmatic demonstration through successful applications in computer models of muscular contraction in the 1980s.

Hospital contract management: a descriptive profile.

PubMed Central

Alexander, J A; Lewis, B L

1984-01-01

Despite the dramatic growth in hospital contract management in the last decade, research only recently has begun to provide insights into the structure, operation, and effectiveness of these arrangements. Two descriptive questions regarding hospital contract management are addressed in an effort to increase correspondence between theoretical and evaluative research in this area: (1) how do contract-managed hospitals differ from traditionally managed hospitals? and (2) how do contract-managed hospitals differ from each other? Principal discriminating variables in the analyses are hospital size, control, urban-rural location, region, management organization control, and management organization size. Results of the analysis on a sample of 406 contract-managed hospitals and 401 unaffiliated hospitals reveal important differences between contract-managed and traditionally managed hospitals as well as among contract management organizations. These findings are discussed in terms of their implications for future research and performance evaluations on contract management arrangements. PMID:6490376

Transforming Wartime Contracting: Controlling Costs, Reducing Risks

DTIC Science & Technology

2011-08-01

reduce the risk of awarding contracts to companies with questionable capability to perform. Expansion of investigative authority and jurisdiction ...A forcing function is needed to ensure widespread and effective adoption of contingency-contracting reform. Otherwise, agency inertia , resistance to...inflamed because jurisdiction over contractors is ambiguous, legal accountability is uncertain, and a clear command-and-control structure is absent. A

Long term accretion history (165-70 Ma) recorded by high-pressure rocks of Diego de Almagro Island (Patagonia, Chile): implications for understanding subduction zone interface tectonic processes

NASA Astrophysics Data System (ADS)

Angiboust, Samuel; Hyppolito, Thais; Glodny, Johannes; Cambeses, Aitor; Monié, Patrick; Garcia-Casco, Antonio; Calderon, Mauricio; Juliani, Caetano

2017-04-01

The Diego de Almagro Island preserves one of the rare remnants of the Mesozoic Chilean paleo-accretionary wedge. This complex, formed by MOR-basalts interleaved with metasedimentary rocks, comprises three major tectonic units with distinct P-T-t paths: the HP granulite (Lazaro unit), the garnet amphibolite (GA) and the blueschist (BS) units. HP granulite-facies metamorphic conditions in the Lazaro Unit are attested by Grt-Cpx-Zo-Prg assemblages associated with trondhjemitic leucosomes (c. 1.3 GPa, 750°C). U-Pb SHRIMP dating of zircon metamorphic rims yields a homogeneous age population of 162 ± 2 Ma for this HT event, in agreement with Sm-Nd dating of peritectic garnet (163 ± 2 Ma and 163 ± 18 Ma). In situ white mica Ar-Ar dating and multi-mineral Rb-Sr dating of LT mylonites (c. 450°C) along the base of the Lazaro Unit reveals partial resetting of HT assemblages during deformation between 115 and 72 Ma. GA unit rocks, structurally below the Lazaro unit, locally preserve eclogite facies parageneses (c. 570°C, 1.7 GPa) that underwent a pervasive stage of amphibolitization during decompression down to 1.3 GPa. U-Pb dating of zircon metamorphic rims and Rb-Sr dating indicate that amphibolitization in GA unit took place at 125-120 Ma. GA unit rocks have been also lately overprinted by another HP-LT assemblage as shown by Si-richer phengite rims and small blue amphibole overgrowths. Conversely, the underlying BS unit does not show strong amphibolite facies overprint as seen in GA and Lazaro units and exhibits slightly cooler peak metamorphic conditions (c. 520°C, 1.7 GPa). Rb-Sr and Ar-Ar dating of these blueschists yield deformation ages between 80 and 70 Ma, i.e. 50 Ma younger than the overlying rocks from the GA unit, and 90 Ma younger than Lazaro unit HP-granulites. This new report sheds light on the formation of the youngest and deepest HP rocks exposed along the Chilean subduction margin. The Diego de Almagro Island represents a unique window onto long-term tectonic processes rooted below the base of the accretionary wedge (c. 40-50 km). The exceptionally long residence time of the earlier accreted material -almost 100 Ma-, enables the record of multiple thermal gradient fluctuations and highlights the variability of the subduction interface thermal structure over tens of millions yrs.

Orogenic-type copper-gold-arsenic-(bismuth) mineralization at Flatschach (Eastern Alps), Austria

NASA Astrophysics Data System (ADS)

Raith, Johann G.; Leitner, Thomas; Paar, Werner H.

2015-10-01

Structurally controlled Cu-Au mineralization in the historic Flatschach mining district (Styria, Austria) occurs in a NE-SW to NNE-WSW oriented vein system as multiple steep-dipping calcite-(dolomite)-quartz veins in amphibolite facies metamorphic rocks (banded gneisses/amphibolites, orthogneisses, metagranitoids) of the poly-metamorphosed Austroalpine Silvretta-Seckau nappe. Vein formation postdated ductile deformation events and Eoalpine (Late Cretaceous) peak metamorphism but predated Early to Middle Miocene sediment deposition in the Fohnsdorf pull-apart basin; coal-bearing sediments cover the metamorphic basement plus the mineralized veins at the northern edge of the basin. Three gold-bearing ore stages consist of a stage 1 primary hydrothermal (mesothermal?) ore assemblage dominated by chalcopyrite, pyrite and arsenopyrite. Associated minor minerals include alloclasite, enargite, bornite, sphalerite, galena, bismuth and matildite. Gold in this stage is spatially associated with chalcopyrite occurring as inclusions, along re-healed micro-fractures or along grain boundaries of chalcopyrite with pyrite or arsenopyrite. Sericite-carbonate alteration is developed around the veins. Stage 2 ore minerals formed by the replacement of stage 1 sulfides and include digenite, anilite, "blue-remaining covellite" (spionkopite, yarrowite), bismuth, and the rare copper arsenides domeykite and koutekite. Gold in stage 2 is angular to rounded in shape and occurs primarily in the carbonate (calcite, Fe-dolomite) gangue and less commonly together with digenite, domeykite/koutekite and bismuth. Stage 3 is a strongly oxidized assemblage that includes hematite, cuprite, and various secondary Cu- and Fe-hydroxides and -carbonates. It formed during supergene weathering. Stage 1 and 2 gold consists mostly of electrum (gold fineness 640-860; mean = 725; n = 46), and rare near pure gold (fineness 930-940; n = 6). Gold in stage 3 is Ag-rich electrum (fineness 350-490, n = 12), and has a high Hg content (up to 11 mass %). The Cu-Au deposits in the Flatschach area show similarities with meso- to epizonal orogenic lode gold deposits regarding the geological setting, the structural control of mineralization, the type of alteration, the early (stage 1) sulfide assemblage and composition of gold. Unique about the Flatschach district is the lower-temperature overprint of copper arsenides (domeykite and koutekite) and copper sulfides (djurleite, yarrowite/spionkopite) on earlier formed sulfide mineralization. Based on mineralogical considerations temperature of stage 2 mineralization was between about 70 °C and 160 °C. Gold was locally mobilized during this low-temperature hydrothermal overprint as well as during stage 3 supergene oxidation and cementation processes.

STRUCTURAL GEOMETRY OF AN EXHUMED UHP TERRANE IN THE EASTERN SULU OROGEN, CHINA: IMPLICATIONS FOR CONTINENTAL COLLISIONAL PROCESSES

NASA Astrophysics Data System (ADS)

Wang, L.; Kusky, T.

2009-12-01

High-precision 1:1,000 mapping of Yangkou Bay, eastern Sulu orogen, defines the structural geometry and history of the world’s most significant UHP (Ultrahigh Pressure) rock exposures. Four stages of folds are recognized in the UHP rocks and associated quartzo-feldspathic gneiss. Eclogite facies rootless F1 and isoclinal F2 folds are preserved locally in coesite-eclogite. Mylonitic to ultramylonitic cosesit-eclogite shear zones separate 5-10-meter-thick nappes of ultramafic-mafic UHP rocks from banded quartzo-feldspathic gneiss. These shear zones are folded, and progressively overprinted by amphibolite and greenschist facies shear zones that become wider with lower grade. The deformation sequences is explained by deep subduction of offscraped thrust slices of oceanic or lower continental crust, caught between the colliding North and South China cratons in the Mesozoic. After these slices were structurally isolated along the plate interface, they were rolled like ball-bearings, in the subduction channel during their exhumation, forming several generations of folds, sequentially lower-grade foliations and lineations, and intruded by several generations of in situ and exotically derived melts. The shear zones formed during different generations of deformation are wider with lower grades, suggesting that deep-crustal/upper mantle deformation operates efficiently (perhaps with more active crystallographic slip systems) than deformation at mid to upper crustal levels.

Post-Paleogene Deformation in central Anatolia, South of Ankara (Turkey)

NASA Astrophysics Data System (ADS)

Rojay, Bora

2014-05-01

The closure of the northern Neo-Tethys took place between Eurasia in the north and northern edge of Afro- Arabian plate in the south since the Early Cretaceous is documented in central Anatolia. It is mated by Cretaceous ophiolitic mélanges thrusted over southwards on to the upper Cretaceous-Paleogene fore-arc and foreland sequences along the northern margins of Haymana and Tuzgölü basins, respectively. Two main deformation episodes are recognized in the region. These include post-Cretaceous-pre Miocene compressional regime and Miocene to mid-Pliocene transcurrent regime dominated extensional deformation. The first regime is characterize by NW-SE directed compressional and contractional deformation dominated by south vergent, large wave length, asymmetric to overturned folds and associated thrust/reverse faults. Some of these reverse faults were reactivated as strike-slip faults with reverse components as evidenced by cross-cutting relationships and overprinting slickensides observed extensively in the field. Along these reactivated faults, echelon calcite veins, fault parallel meter thick silica walls with repeated phases of deformation are very common. Following the Miocene, the region is affected by a NNE-SSW to NE-SW directed extension, possibly resulted from the interaction of Tuzgölü Fault with the northwards convex splays of dextral North Anatolian Fault extending into the region. As a conclusion, the Paleogene sequences with ophiolitic mélanges are deformed under NNE-SSW directed compression related to the development of dextral strike slip tectonics during post-Paleogene-pre-Miocene period. Keywords:fault plane slip data, transcurrent regime, post-Paleogene, central Anatolia.

Dolomitization and over-dolomitization in the Vajont limestone (Dolomiti Bellunesi, Italy) controlled by Mesozoic normal faults: a microstructural and diagenesis study

NASA Astrophysics Data System (ADS)

Cortinovis, Silvia; Swennen, Rudy; Bistacchi, Andrea

2015-04-01

The Vajont Gorge (Dolomiti Bellunesi, Italy) provides spectacular outcrops of Jurassic limestones (Vajont Limestone Formation) in which Mesozoic faults and fracture corridors are continuously exposed. Some of these faults acted as conduits for Mg-enriched hydrothermal fluids resulting in structurally-controlled dolomitization of the limestone. The dolomitization resulted in several dolomite bodies (100-200 m thick and several hundreds of meters along fault strike) that are particularly interesting as reservoir analogues for hydrocarbon, CO2, or water-bearing systems. The dolomitization process occurred after deposition and compaction of the oolitic limestone (dolomitization post-dates a dissolution event that affected the internal parts of the oolites), but before the Alpine contractional deformation. In fact, the meso-structural data collected in the Vajont Gorge allowed the reconstruction of a 3D model showing that the circulation of the dolomitizing fluids into the limestone host rock, but also the late stage of porosity reduction (strong pore filling due to over-dolomitization) were controlled by normal faults and fracture corridors interpreted as Pre-Alpine (Jurassic or Cretaceous). Later on, the influence of Alpine (Tertiary) deformation have been very limited in the studied volume. For instance dolomite veins are sometimes overprinted by bed-inclined stylolites consistent with Alpine shortening axes, but no large Alpine fault is present in the studied outcrops. Cathodoluminescence microscopy allowed recognizing different growth stages saddle dolomite crystals, which point to varying precipitation conditions during three main stages of dolomitization. Dolomite and calcite crystal twinning suggests deformation under increasing temperature conditions, consistent with intracrystalline plasticity deformation mechanisms. The presence of cataclasites composed of hydrothermal dolostone clasts, in turn cemented by dolomite, or of dolomite veins and compaction/deformation bands in high porosity dolomite bodies, is an additional argument pointing to the close interaction between tectonic deformation and fluid circulation. Particularly, it shows how tectonics controlled fluid circulation both in the first stages of dolomitization, when porosity was created, and in later stages, when porosity was strongly reduced due to over-dolomitization. The microstructure of fault breccia suggests a high-pressure of injected fluids and is useful to reconstruct the chronology of events involved in the formation and evolution of dolostone bodies. A study of quasi-steady-state (e.g. crack and seal) vs. episodic/seismic (mass precipitation, cavitation) deformation processes is under way to investigate the possible correlation between fluid injection events and the progressive slip on faults.

76 FR 5431 - Publication of FY 2010 Service Contract Inventory

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-31

... available to the public at http://www.treasury.gov/about/organizational-structure/offices/Pages/Office-of... employees and contractors in the Department is effectively balanced, if contract performance is satisfactory...

Architectural & engineering handbook

DOT National Transportation Integrated Search

2003-05-21

The Architectural and Engineering (A&E) Handbook provides an overview of the contracting process for A&E consultant services. Produced by the Division of Procurement and Contracts, this handbook provides guidance and a structured process for the plan...

48 CFR 1252.217-76 - Liability and insurance.

Code of Federal Regulations, 2011 CFR

2011-10-01

... required by the Contracting Officer, the Contractor shall execute a formal assignment or transfer of the... of and shall not affect the pricing structure of the contract, and are additional to the compensation...

Structural Basis for the Regulation of Muscle Contraction by Troponin and Tropomyosin

PubMed Central

Galińska-Rakoczy, Agnieszka; Engel, Patti; Xu, Chen; Jung, HyunSuk; Craig, Roger; Tobacman, Larry S.; Lehman, William

2008-01-01

The molecular switching mechanism governing skeletal and cardiac muscle contraction couples the binding of Ca2+ on troponin to the movement of tropomyosin on actin filaments. Despite years of investigation, this mechanism remains unclear because it has not yet been possible to directly assess the structural influence of troponin on tropomyosin that causes actin filaments, and hence myosin-crossbridge cycling and contraction, to switch on and off. A C-terminal domain of troponin I is thought to be intimately involved in inducing tropomyosin movement to an inhibitory position that blocks myosin-crossbridge interaction. Release of this regulatory, latching domain from actin after Ca2+-binding to TnC presumably allows tropomyosin movement away from the inhibitory position on actin, thus initiating contraction. However, the structural interactions of the regulatory domain of TnI with tropomyosin and actin that cause tropomyosin movement are unknown and thus the regulatory process is not well defined. Here, thin filaments were labeled with an engineered construct representing C-terminal TnI and then 3D-EM was used to resolve where troponin is anchored on actin-tropomyosin. EM-reconstruction showed how TnI-binding to both actin and tropomyosin at low-Ca2+ competes with tropomyosin for a common site on actin and drives tropomyosin movement to a constrained, relaxing position to inhibit myosin-crossbridge association. Thus the observations reported reveal the structural mechanism responsible for troponin-tropomyosin-mediated steric-interference of actin-myosin interaction that regulates muscle contraction. PMID:18514658

Agarose Gel Electrophoresis Reveals Structural Fluidity of a Phage T3 DNA Packaging Intermediate

PubMed Central

Serwer, Philip; Wright, Elena T.

2012-01-01

We find a new aspect of DNA packaging-associated structural fluidity for phage T3 capsids. The procedure is (1) glutaraldehyde cross-linking of in vivo DNA packaging intermediates for stabilization of structure and then (2) determining of effective radius by two-dimensional agarose gel electrophoresis (2d-AGE). The intermediates are capsids with incompletely packaged DNA (ipDNA) and without an external DNA segment; these intermediates are called ipDNA-capsids. We initially increase production of ipDNA-capsids by raising NaCl concentration during in vivo DNA packaging. By 2d-AGE, we find a new state of contracted shell for some particles of one previously identified ipDNA-capsid. The contracted shell-state is found when ipDNA length/mature DNA length (F) is above 0.17, but not at lower F. Some contracted-shell ipDNA-capsids have the phage tail; others do not. The contracted-shell ipDNA-capsids are explained by premature DNA maturation cleavage that makes accessible a contracted-shell intermediate of a cycle of the T3 DNA packaging motor. The analysis of ipDNA-capsids, rather than intermediates with uncleaved DNA, provides a simplifying strategy for a complete biochemical analysis of in vivo DNA packaging. PMID:22222979

Multiphase Structural Evolution of a Continental Margin During Obduction Orogeny: Insights From the Jebel Akhdar Dome, Oman Mountains

NASA Astrophysics Data System (ADS)

Grobe, A.; Virgo, S.; von Hagke, C.; Urai, J. L.; Littke, R.

2018-03-01

The structural evolution of the carbonate platform in the footwall of the Semail ophiolite emplaced onto the passive continental margin of Arabia helps to better understand the early stages of obduction-related orogens. These early stages are rarely observable in other orogens as they are mostly overprinted by later mountain building phases. We present an extensive structural analysis of the Jebel Akhdar anticline, the largest tectonic window of the Oman Mountains, and integrate it on different scales. Outcrop observations can be linked to plate motion data, providing an absolute timeframe for structural generations consistent with radiometric dating of veins. Top-to-S overthrusting of the Semail ophiolite and Hawasina nappes onto the carbonate platform during high plate convergence rates between Arabia and Eurasia caused rapid burial and overpressure, generation and migration of hydrocarbons, and bedding-confined veins, but no major deformation in the carbonate platform. At reduced convergence rates, subsequent tectonic thinning of the ophiolite took place above a top-to-NNE, crustal-scale ductile shear zone, deforming existing veins and forming a cleavage in clay-rich layers in early Campanian times. Ongoing extension occurred along normal- to oblique-slip faults, forming horst-graben structures and a precursor of the Jebel Akhdar dome (Campanian to Maastrichtian). This was followed by NE-SW oriented ductile shortening and the formation of the Jebel Akhdar dome, deforming the earlier structures. Thereafter, exhumation was associated with low-angle normal faults on the northern flank of the anticline. We correlate the top-to-NNE crustal-scale shear zone with a similar structure in the Saih Hatat window to develop a unified model of the tectonic evolution of the Oman Mountains.

Probable Mid-Miocene Caldera in the Modoc Plateau, Northeast California

NASA Astrophysics Data System (ADS)

Bowens, T. E.; Grose, T. L.

2001-12-01

Regional geologic mapping within the Modoc Plateau has resulted in the discovery of a large volcanotectonic anomaly some 21-km in diameter approximately 50-km WSW of the city of Alturas in Modoc County, California. Centrally located within this anomaly lies a structural depression some 11-km in diameter which, based on structural, lithologic, and geophysical characteristics, is believed to represent a deeply eroded mid-Miocene caldera. The region extending outward some 5-km from the proposed caldera displays a sharp, localized structural deflection from a NNW to a WNW structural grain. Lying inboard of this deflection, a series of regionally discordant E-W to NE trending, generally down to the north, normal faults were discovered which are believed to represent rim faults to an ancient caldera. Bedding within the hanging wall of these discordant structures displays highly contorted and regionally anomalous dips. By stereographic removal of the regional northeast dip overprinting the area, the anomalous dips were found to display a radial, steeply inward dipping pattern in close proximity to the proposed rim structures while dips located further inboard are generally flat-lying. Lithologies within the proposed caldera are regionally anomalous and include abundant tuffaceous and flow dominated breccias, closed basin organic sedimentary facies, and an anomalous concentration of volcanic centers of both mafic and felsic compositions. One of these intrusives was age dated at 12.9 Ma indicating the anomaly formed during mid-Miocene time. The location of the proposed caldera is associated with a +20 mgal gravity high, which stands in contrast to a lesser high of +10 mgal associated with the Medicine Lake Caldera some 50-km to the northwest. This combination of structural, lithologic, and geophysical evidence leads to the interpretation of a caldera at this location, herein termed the Stone Coal Valley Caldera.

Structural alterations of thin actin filaments in muscle contraction by synchrotron X-ray fiber diffraction.

PubMed

Wakabayashi, Katsuzo; Sugimoto, Yasunobu; Takezawa, Yasunori; Ueno, Yutaka; Minakata, Shiho; Oshima, Kanji; Matsuo, Tatsuhito; Kobayashi, Takakazu

2007-01-01

Strong evidence has been accumulated that the conformational changes of the thin actin filaments are occurring and playing an important role in the entire process of muscle contraction. The conformational changes and the mechanical properties of the thin actin filaments we have found by X-ray fiber diffraction on skeletal muscle contraction are explored. Recent studies on the conformational changes of regulatory proteins bound to actin filaments upon activation and in the force generation process are also described. Finally, the roles of structural alterations and dynamics of the actin filaments are discussed in conjunction with the regulation mechanism and the force generation mechanism.

Structural Basis of Merlin Tumor Suppressor Functions in Neurofibromatosis-2

DTIC Science & Technology

2013-10-01

Neurofibromatosis -2 PRINCIPAL INVESTIGATOR: Tina Izard CONTRACTING ORGANIZATION: The Scripps Research Institute La Jolla, CA 92037-1000...30September2012-29September2013 4. TITLE AND SUBTITLE Structural Basis of Merlin Tumor Suppressor Functions in Neurofibromatosis -2 5a. CONTRACT...14. ABSTRACT Loss-of-function mutations in the neurofibromatosis -2 (NF2) gene lead to familial and sporadic neurological malignancies in man

Passive and Active Contributions to Glenohumeral Stability

DTIC Science & Technology

2001-10-25

physiological muscle contraction during free arm suspension and proportional to muscle physiological cross- sectional area [15] (Phys Load); ditto...of muscle contraction around GH-joint. Stiffness of the GH capsuloligamentous structure, which is the ratio of the force required to stretch the...important active stabilizer in inferior stability. Our results also suggested that low-level muscle activity (2% of maximum muscle contraction ), representing

Surface Modification of Orthodontic Bracket Models via Ion Implantation: Effect on Coefficients of Friction

DTIC Science & Technology

1989-01-01

FEB 2 2 1990 Stephen Walter Andrews, D.M.D. The University of North Carolina at Chapel Hill Department of Orthodontics School of Dentistry 1989 Robert...PROJECT TASK WORK UNIT ELEMENT NO. NO. NO. ACCESSION NO. 11. TITLE (Include Security Classification) (UNCLASSIFIED) SURFACE MODIFICATION OF ORTHODONTIC ...Previous editions are obsolete. SECURITY CLASSIFICATION OF THIS PAGE AFIT/CI "OVERPRINT" SURFACE MODIFICATION OF ORTHODONTIC BRACKET MODELS VIA ION

Psychological contracts and commitment amongst nurses and nurse managers: a discourse analysis.

PubMed

McCabe, T J; Sambrook, Sally

2013-07-01

Few studies explore the link between the psychological contracts and the commitment of nursing professionals in the healthcare sector, and how perceived breaches of the psychological contract can impact on nurses' commitment levels. This study explores the connections between the psychological contracts and organisational and professional commitment of nurses and nurse managers. Semi-structured interviews were conducted with nurses and nurse managers, to explore the connections between their psychological contracts and organisational and professional commitment. Large acute and small community organisation within the British National Health Service. 28 nurses and 11 nurse managers working within an acute and a community sector organisation - 20 and 19 in each organisation. Participants were selected through a process of purposive sampling, reflecting variations in terms of age, grade, ward and tenure. A discourse analysis was conducted on the qualitative data from the thirty nine semi-structured interviews. Two overall themes emerged, professional and managerial values. Professional values included the sub-themes: professional recognition; immediate work environment - leadership and peer support; professional development and progression. Sub-themes under managerial values included: involvement; general management; resource management. The findings suggest that nurses and nurse managers are governed by relational psychological contracts, underpinned by an affective and to a lesser extent normative commitment towards the nursing profession. They emphasise 'professional values', and professional commitment, as the basis for positive psychological contracts amongst nursing professionals. There was anecdotal evidence of relational psychological contract breach, with decreasing job satisfaction as the outcome of perceived psychological contract breach. Positive psychological contracts and commitment levels amongst nursing professionals can be supported by managers been aware and sensitive to nursing discourses, and managing their expectations through greater involvement and leadership development. Copyright © 2012 Elsevier Ltd. All rights reserved.

The Mt. Ochi melange (South Evvia Island, Greece): a case study for HP metamorphism and syn-convergent exhumation.

NASA Astrophysics Data System (ADS)

Moustaka, Eleni; Soukis, Konstantinos; Huet, Benjamin; Lozios, Stylianos; Magganas, Andreas

2014-05-01

The Attic-Cycladic complex (central Aegean Sea, Greece) experienced profound extension since at least the Oligo-Miocene boundary during which the previously thickened crust was reworked by a series of detachments forming the NE directed North Cycladic Detachment System (NCDS) and the SSW directed West Cycladic Detachment System (WCDS). South Evvia Island is located at the northwestern part of the Attic Cycladic complex linking the highly thinned and polymetamorphosed central part of the complex with mainland Greece. Furthermore, greenschists-facies retrograde metamorphism has only partially overprinted the HP mineral assemblages. Consequently, it is an ideal area to study tectonic processes associated with subduction, HP metamorphism and subsequent exhumation from eclogitic depths to the surface. Geological mapping in 1:2:000 scale revealed that the tectonostratigraphy of Mt. Ochi includes three distinct units all metamorphosed in HP conditions followed by greenschist facies overprint. These units are from top to bottom a) the Ochi Unit, a thick metavolcanosedimentary sequence with some intensely folded cipoline marble intercalations and isolated occurrences of metabasic rocks b) the ophiolitic mélange (metagabbros, metawherlites, peridotites, metabasites within a metasedimentary+serpentinite matrix) and c) the lowermost Styra Unit, a cipoline marble-dominated unit with thin mica schists and rare quartzitic layers often boudinaged. The thrust fault that was responsible for the juxtaposition of these three units acted in an early stage during HP metamorphism and it was isoclinally folded and sheared by the following syn-metamorphic deformation events. Detailed structural study in meso- and microscopic scale combined with petrological and geochemical analyses of the Mt Ochi rocks led to the distinction of at least three syn-metamorphic and two post-metamorphic deformation episodes that affected all units. The oldest structure identified is a relic foliation formed by the mineral assemblage Na-amphibole + lawsonite seen as inclusion in epidote porphyroblasts within the melange. It could represent a structure of the prograde path but it could also have formed during the peak HP event. This is followed by successive folding episodes that are related to axial plane foliations and a ~E-W intersection/stretching lineation formed by typical blueschist- to epidote-blueschist facies mineral assemblages. The main foliation that can be observed in all three units is a greenschist-facies axial plane foliation accompanied by a ~ENE-WSW stretching lineation. The shear sense during the prograde path is constantly towards the WSW. In the greenschists-facies an unambiguous top-to ENE can be observed mostly in mylonitic rocks. The following deformation episodes include semi-brittle to brittle structures (shear bands brittle open folds, crenulation cleavage, and faults with increasingly higher-angle) that are not as penetrative and record the passage of the units through the brittle-ductile transitions and to higher structural levels. The kinematics of these late episodes is also towards the NE. Based on the above, the Mt Ochi HP units exhibit a common tectonometamorphic evolution since at least the early stages of the prograde path. The Ochi Unit/Styra Unit contact is a structure that formed prior to or during peak HP metamorphism and therefore it couldn't have served as the normal fault to an extrusion wedge.

48 CFR 1252.217-76 - Liability and insurance.

Code of Federal Regulations, 2010 CFR

2010-10-01

...) The Contractor shall not make any allowance in the contract price for the inclusion of any premium... of and shall not affect the pricing structure of the contract, and are additional to the compensation...

48 CFR 12.207 - Contract type.

Code of Federal Regulations, 2010 CFR

2010-10-01

...) Competitive procedures (e.g., the procedures in 6.102, the set-aside procedures in Subpart 19.5, or... pricing structure is not practicable. The D&F for this contract shall be approved one level above the...

The Contract Management Body of Knowledge: A Comparison of Contracting Competencies

DTIC Science & Technology

2013-12-01

SME subject matter expert SOW statement of work TINA Truth in Negotiations Act UCC uniform commercial code WBS work breakdown structure xv...documents whose terms and condition are legally enforceable. Sources of law and guidance covered include the uniform commercial code ( UCC ), Federal...contracting including the uniform commercial code ( UCC ), Federal Acquisition Regulation (FAR), as well as various other laws pertaining to both

Effects of different duration isometric contractions on tendon elasticity in human quadriceps muscles

PubMed Central

Kubo, Keitaro; Kanehisa, Hiroaki; Fukunaga, Tetsuo

2001-01-01

The present study aimed to investigate the influence of isometric training protocols with long- and short-duration contractions on the elasticity of human tendon structures in vivo. The elasticity was assessed through in vivo determination of the elongation (L) of the tendons and aponeuroses using ultrasonography, while the subjects performed ramp isometric exercise up to maximum voluntary contraction (MVC).Eight young males completed 12 weeks (4 days per week) of a unilateral isometric training programme on knee extensors, which consisted of two different combinations of contraction and relaxation times at 70 % MVC: one leg was trained using a short-duration protocol (3 sets of 50 repetitions of contraction for 1 s and relaxation for 2 s), and the other leg was trained using a long-duration protocol (4 sets of a combination of contraction for 20 s and relaxation for 1 min). The training volume per session, expressed as the integrated torque, was the same for the two protocols.Both protocols resulted in a significant increase in MVC: 31.8 ± 17.2 % for the short-duration protocol and 33.9 ± 14.4 % for the long-duration protocol. Moreover, the training produced significant increases in the muscle volume of the constituents of the quadriceps femoris, with similar relative gains for the two protocols: 7.4 ± 3.9 % for the short-duration protocol and 7.6 ± 4.3 % for the long-duration protocol.The short-duration protocol produced no significant change in L values at any of the force production levels. For the long-duration protocol, however, the L values above 550 N were significantly shorter after training. Analysis revealed that the group × test time interaction effect on tendon stiffness was significant. Stiffness increased significantly for the long-duration protocol, but not for the short-duration protocol.The present study demonstrates a greater increase in stiffness of human tendon structures following isometric training using longer duration contractions compared to shorter contractions. This suggests that the changes in the elasticity of the tendon structures after resistance training may be affected by the duration of muscle contraction. PMID:11600697

Digenetic Changes in Macro- to Nano-Scale Porosity in the St. Peter Sandstone:L An (Ultra) Small Angle Neutron Scattering and Backscattered Electron Imagining Analysis

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

Anovitz, Lawrence; Cole, David; Rother, Gernot

2013-01-01

Small- and Ultra-Small Angle Neutron Scattering (SANS and USANS) provide powerful tools for quantitative analysis of porous rocks, yielding bulk statistical information over a wide range of length scales. This study utilized (U)SANS to characterize shallowly buried quartz arenites from the St. Peter Sandstone. Backscattered electron imaging was also used to extend the data to larger scales. These samples contain significant volumes of large-scale porosity, modified by quartz overgrowths, and neutron scattering results show significant sub-micron porosity. While previous scattering data from sandstones suggest scattering is dominated by surface fractal behavior over many orders of magnitude, careful analysis of ourmore » data shows both fractal and pseudo-fractal behavior. The scattering curves are composed of subtle steps, modeled as polydispersed assemblages of pores with log-normal distributions. However, in some samples an additional surface-fractal overprint is present, while in others there is no such structure, and scattering can be explained by summation of non-fractal structures. Combined with our work on other rock-types, these data suggest that microporosity is more prevalent, and may play a much more important role than previously thought in fluid/rock interactions.« less

Consistent Top-to-the-foreland Directed Deformation from Floor to Roof in the Seve Nappe Complex (SNC), Jämtland, Sweden

NASA Astrophysics Data System (ADS)

Bender, H.; Ring, U.; Almqvist, B. S. G.; Glodny, J.; Grasemann, B.; Stephens, M. B.

2016-12-01

The recent COSC-1 drilling programme (Lorenz et al., 2015), discovery of microdiamonds (Majka et al., 2014) and discussion of extrusion-wedge tectonics (Grimmer et al., 2015) outline the importance of the Seve Nappe Complex (SNC) and its key role during the Caledonian orogeny. The kinematic evolution of the SNC is crucial for better understanding the entire mountain belt. Thorough structural mapping of the SNC and adjacent units was conducted in western and northern Jämtland, central Sweden. Complementary microstructural investigations strengthen the field observations and show consistent top-to-the-SE directed movement through all studied tectonic units. Amphibolite-facies deformation can be inferred from fabrics in the SNC, which are overprinted by greenschist-facies structures showing the same kinematics throughout the studied section of the nappe stack. These data indicate persistence of the same foreland-directed kinematics over a wide range of pressure-temperature conditions in space and time. Currently proposed models for exhuming high-grade metamorphic rocks in collisional orogens fail to explain these observations and highlight the need for discussing new tectonic concepts for the Scandinavian Caledonides. References: Grimmer et al., 2015, Geology 43 (4); Lorenz et al., 2015, Scientific Drilling 19; Majka et al. 2014, Geology 42 (12).

Geological Mapping of Fortuna Tessera (V-2): Venus and Earth's Archean Process Comparisons

NASA Technical Reports Server (NTRS)

Head, James W.; Hurwitz,D. M.; Ivanov, M. A.; Basilevsky, A. T.; Kumar, P. Senthil

2008-01-01

The geological features, structures, thermal conditions, interpreted processes, and outstanding questions related to both the Earth's Archean and Venus share many similarities and we are using a problem-oriented approach to Venus mapping, guided by insight from the Archean record of the Earth, to gain new insight into the evolution of Venus and Earth's Archean. The Earth's preserved and well-documented Archean record provides important insight into high heat-flux tectonic and magmatic environments and structures and the surface of Venus reveals the current configuration and recent geological record of analogous high-temperature environments unmodified by subsequent several billion years of segmentation and overprinting, as on Earth. Elsewhere we have addressed the nature of the Earth's Archean, the similarities to and differences from Venus, and the specific Venus and Earth-Archean problems on which progress might be made through comparison. Here we present the major goals of the Venus-Archean comparison and show how preliminary mapping of the geology of the V-2 Fortuna Tessera quadrangle is providing insight on these problems. We have identified five key themes and questions common to both the Archean and Venus, the assessment of which could provide important new insights into the history and processes of both planets.

Linking microcracks and mineral zoning of detachment-exhumed granites to their tectonomagmatic history: Evidence from the Salihli and Turgutlu plutons in western Turkey (Menderes Massif)

NASA Astrophysics Data System (ADS)

Catlos, Elizabeth J.; Baker, Courteney B.; Sorensen, Sorena S.; Jacob, Lauren; Çemen, Ibrahim

2011-05-01

The Menderes Massif (western Turkey) is a metamorphic core complex that displays linked syntectonic plutonism and detachment faulting. Fabrics in S-type peraluminous granites (Salihli and Turgutlu) in the detachment (Alaşehir) footwall change from isotropic to protomylonitic to mylonitic towards the structure. Samples from the isotropic and protomylonitic zones were imaged in transmitted light, cathodoluminescence (CL), backscattered (BSE), and secondary electrons (SE), and show that these rocks contain abundant microcracks, and that plagioclase grains have zoning consistent with magma mixing. The granites contain fluid inclusion planes (FIPs), myrmekite replacing plagioclase, and the removal of blue luminescence in K-feldspar along microcracks and grain boundaries. Calcite and hydrous minerals commonly fill microcracks. The samples record features that formed due to (1) magma crystallization and ductile deformation (FIPs, mineral zoning), (2) changes in P and/or T (impingement and stress-induced microcracks in protomylonitic rocks), and (3) differences in intrinsic mineral properties (radial, cleavage, blunted, and deflected microcracks). Overprinted microcracks indicate exhumation during pulses. The Middle Miocene ages of these granites reported elsewhere are similar to those from large-scale extensional structures in Greece's Cycladic Massif. The Menderes and Cycladic core complexes may have developed simultaneously due to the widespread intrusion of subduction-related granitoids.

In situ rutile petrochronology: texture-related T, Paleoproterozoic inheritance and a Pan-African overprint in the oldest subduction-related eclogites, Usagaran Orogen, Tanzania

NASA Astrophysics Data System (ADS)

Moeller, A.; Kraus, K.; Herms, P.; Appel, P.; Raase, P.

2014-12-01

Rutile U-Pb thermochronology is applied successfully by both TIMS and beam methods to date cooling events in mafic and metapelitic rocks, as well as in detrital studies. The Zr-in-rutile thermometer is very robust to thermal diffusion, and generally requires complete recrystallization to change recorded crystallization temperatures. Evidence for diffusion of HFSE elements in rutile is sparse; whereas U-Pb chronology generally records diffusion controlled cooling from the last event. This study follows conventional thermobarometry and U-Pb TIMS results on monazite, sphene and rutile of Möller et al. (1995) establishing a 2 Ga eclogite facies event from MORB-like metabasic, and metapelitic rocks in the Usagaran Orogen of Tanzania, interpreted to be the oldest outcrops of subduction-related eclogites. Rutile from both rock types were discordant near a ca. 500 Ma lower intercept, confirming a thermal overprint postulated on the basis of K-Ar and Rb-Sr mica ages by e.g. Wendt et al. (1972). The age of the eclogite-facies event was confirmed by U-Pb zircon dating of a 1991±2 Ma crosscutting pegmatite (Collins et al., 1999). We present in situ LA-ICP-MS rutile petrochronology on five metabasic and metapelitic eclogite facies samples with variable retrograde amphibolite-facies recrystallization. Thermometry confirms conventional Fe-Mg results, including higher peak temperatures in metabasites. Traverses on rutile inclusions in large garnet prophyroblasts in metapelites show increasing temperatures from cores outwards and a slight decrease towards outermost rims, with peak T coinciding with highest Mg# and highest grossular content, hence consistent with preservation of prograde zoning in the garnets and a brief eclogite facies event. Large rutiles (800μm) in recrystallized samples record temperature zoning profiles. U-Pb results show inheritance of near concordant 2 Ga domains, but dominantly confirm the ca. 490 Ma amphibolite facies overprint. The study is an excellent example of the potential of in-situ rutile petrochronology in complex, polymetamorphic rocks when meticulous attention is given to textural context. Möller et al., 1995, Geology, v. 23, p. 1067-1070. Collins et al., 2004, Earth Planet. Sci. Lett., v. 224, p. 175-192. Wendt et al., 1972, 24th Internat. Geol. Congr., Proc., p. 295-314.

Hydrothermal oxidation in the Biwabik Iron Formation, MN, USA

NASA Astrophysics Data System (ADS)

Losh, Steven; Rague, Ryan

2018-02-01

Precambrian iron formations throughout the world, notably in Australia, Brazil, and South Africa, show evidence of hypogene (≥ 110 °C, mostly > 250 °C) oxidation, alteration, and silica dissolution as a result of tectonic or magmatic activity. Although hydrothermal oxidation has been proposed for the prototype Lake Superior-type iron formation, the Biwabik Iron Formation in Minnesota (USA), it has not been documented there. By examining oxidized and unoxidized Biwabik Iron Formation in three mines, including material from high-angle faults that are associated with oxidation, we document an early hypogene oxidation event ( 175 °C) involving medium-salinity aqueous fluids (8.4 ± 4.9 wt% NaCl equiv) that infiltrated iron formation along high-angle faults. At the Hibbing Taconite Mine, hydrothermal fluids oxidized iron carbonates and silicates near faults, producing goethite ± quartz. In contrast with much of the oxidized iron ores on the Mesabi Range, silica was not removed but rather recrystallized during this event, perhaps lying in a rock-dominated system at low cumulative fluid flux. During the hydrothermal oxidation event in the Hibbing Taconite deposit, quartz-filled microfractures and irregular inclusions commonly formed in coarse variably oxidized magnetite, currently the ore mineral: these inclusions degrade the ore by introducing excess silica in magnetic concentrate. Hydrothermal oxidation at Hibbing Taconite Mine is overprinted by later, relatively minor supergene oxidation both along faults and near the surface, which locally dissolved quartz. At the Fayal Reserve Mine, widespread silicate and carbonate gangue dissolution and iron oxidation was followed by precipitation of pyrite, Mn-siderite, apatite, and other minerals in void spaces, which prevented post-oxidation compaction and significant volume loss in the sampled rocks. Although definitive temperature data for this assemblage are needed, the weight of evidence indicates that this mineralization is hypogene. The association of oxidation with epithermal conditions constrains the oxidation and subsequent mineralization to have taken place during the Precambrian, the only time when these rocks would have experienced the necessary temperatures. The mineralization at Fayal Reserve shows little supergene overprint: pyrite is largely unoxidized. Hydrothermal oxidation in both mines was likely produced by basinal fluids that were expelled during the 1.83-1.87 Ga Penokean Orogeny, and mixing with meteoric fluids along faults, although a 1.1 Ga rift-related fluid flow event is also possible. Later supergene overprinting of the iron formation was minor.

Lightweight Material Patches Allow for Quick Repairs

NASA Technical Reports Server (NTRS)

2010-01-01

Cornerstone Research Group Inc., of Dayton, Ohio, has been the recipient of 16 Small Business Innovation Research (SBIR) contracts with NASA with a variety of different focuses, including projects like creating inflatable structures for radio frequency antennas and, most recently, healable polymer matrix composites for future space vehicles. One of its earlier SBIR contracts, with Kennedy Space Center, led to the development of a new type of structural patch for a variety of consumer uses: Rubbn Repair, for automotive uses; and Rec Repair for the outdoors and adventure market. Both are flexible, heat-activated structural patches.

Is there lattice contraction in multicomponent metal oxides? Case study for GdVO4:Eu3+ nanoparticles.

PubMed

Yang, Liusai; Li, Liping; Zhao, Minglei; Fu, Chaochao; Li, Guangshe

2013-08-02

Metal oxide nanomaterials have been found to have great potential for diverse applications due to their unique relationships between structure and properties. Lattice expansion as particle size reduces was previously considered to be general for metal oxide nanomaterials. It is now a great challenge to see if lattice contraction could be induced by the size effect for metal oxide nanomaterials. ABO4 metal oxides (e.g., CaWO4, GdVO4, and CdWO4) are some of the most important functional materials with many applications, while such oxides at the nanoscale are never reported to show a lattice contraction. This work presents a first report on the variation from lattice expansion to lattice contraction by tuning the microstructures of GdVO4:Eu(3+) nanocrystals. A hydrothermal method was adopted to synthesize GdVO4:Eu(3+) nanocrystals, and then these nanoparticles were calcined at 600 ° C in air. It is found that particle size reduction led to a lattice contraction for the calcined samples, which is in contrast to the lattice expansion observed for the hydrothermally synthesized counterparts or many other metal oxide nanomaterials. In addition, the lattice symmetry of the calcined samples remained almost a constant. The results indicate that the negative surface stress was eliminated by calcination treatment, leading to a homogeneous compression process in the lattice structure of the calcined GdVO4:Eu(3+) nanocrystals. Furthermore, Eu(3+) was taken as a structural probe and a luminescence center to study the local environments pertinent to these structural changes and to optimize the photoluminescence performance.

Structural basis for the regulation of muscle contraction by troponin and tropomyosin.

PubMed

Galińska-Rakoczy, Agnieszka; Engel, Patti; Xu, Chen; Jung, Hyunsuk; Craig, Roger; Tobacman, Larry S; Lehman, William

2008-06-20

The molecular switching mechanism governing skeletal and cardiac muscle contraction couples the binding of Ca2+ on troponin to the movement of tropomyosin on actin filaments. Despite years of investigation, this mechanism remains unclear because it has not yet been possible to directly assess the structural influence of troponin on tropomyosin that causes actin filaments, and hence myosin-crossbridge cycling and contraction, to switch on and off. A C-terminal domain of troponin I is thought to be intimately involved in inducing tropomyosin movement to an inhibitory position that blocks myosin-crossbridge interaction. Release of this regulatory, latching domain from actin after Ca2+ binding to TnC (the Ca2+ sensor of troponin that relieves inhibition) presumably allows tropomyosin movement away from the inhibitory position on actin, thus initiating contraction. However, the structural interactions of the regulatory domain of TnI (the "inhibitory" subunit of troponin) with tropomyosin and actin that cause tropomyosin movement are unknown, and thus, the regulatory process is not well defined. Here, thin filaments were labeled with an engineered construct representing C-terminal TnI, and then, 3D electron microscopy was used to resolve where troponin is anchored on actin-tropomyosin. Electron microscopy reconstruction showed how TnI binding to both actin and tropomyosin at low Ca2+ competes with tropomyosin for a common site on actin and drives tropomyosin movement to a constrained, relaxing position to inhibit myosin-crossbridge association. Thus, the observations reported reveal the structural mechanism responsible for troponin-tropomyosin-mediated steric interference of actin-myosin interaction that regulates muscle contraction.

Does bargaining affect Medicare prescription drug plan reimbursements to independent pharmacies?

PubMed

Tang, Yuexin; Xie, Yang; Urmie, Julie M; Doucette, William R

2011-01-01

To examine how pharmacy bargaining activities affect reimbursement rates in Medicare Part D prescription drug plan (PDP) contracts, controlling for pharmacy quality attributes, market structures, and area socioeconomic status. Cross-sectional study. Six Medicare regions throughout the United States between October and December 2009. Random sample of 1,650 independent pharmacies; 321 returned surveys containing sufficient responses for analysis. Pharmacies were surveyed regarding PDP reimbursement rates, costs, and cash prices of two popular prescription drugs (atorvastatin calcium [Lipitor-Pfizer] and lisinopril, 1-month supply of a common strength), as well as pharmacy bargaining activities and quality attributes. Data also were used from the National Council for Prescription Drug Programs pharmacy database, the 2000 U. S. Census, and the 2006 Economic Census on local market structures and area socio-economic status. PDP reimbursement rates. For the brand-name drug atorvastatin calcium, the PDP reimbursement was positively related to a pharmacy's request for a contract change (β = 0.887, P < 0.05), whereas other bargaining activities were not significantly related to PDP reimbursement. However, for the generic drug lisinopril, no bargaining activities were found to be significantly related to the PDP reimbursement. Pharmacy request for a contract change was associated with higher reimbursement rates for the brand-name drug atorvastatin calcium in PDP contracts, after controlling for pharmacy quality attributes, local market structures, and area socioeconomic status; this finding likely applies to other brand-name drugs because of the structure of the contracts. Our results suggest that independent pharmacies are more likely to acquire higher reimbursement rates by engaging in active bargaining with third-party payers.

Population-based contracting (population health): part II.

PubMed

Jacofsky, D J

2017-11-01

Modern healthcare contracting is shifting the responsibility for improving quality, enhancing community health and controlling the total cost of care for patient populations from payers to providers. Population-based contracting involves capitated risk taken across an entire population, such that any included services within the contract are paid for by the risk-bearing entity throughout the term of the agreement. Under such contracts, a risk-bearing entity, which may be a provider group, a hospital or another payer, administers the contract and assumes risk for contractually defined services. These contracts can be structured in various ways, from professional fee capitation to full global per member per month diagnosis-based risk. The entity contracting with the payer must have downstream network contracts to provide the care and facilities that it has agreed to provide. Population health is a very powerful model to reduce waste and costs. It requires a deep understanding of the nuances of such contracting and the appropriate infrastructure to manage both networks and risk. Cite this article: Bone Joint J 2017;99-B:1431-4. ©2017 The British Editorial Society of Bone & Joint Surgery.

High-Nickel Iron-Sulfides in Anhydrous, Gems-Rich CP IDPs

NASA Technical Reports Server (NTRS)

FLynn, G. J.; Keller, L. P.; Wirick, S.; Hu, W.; Li, L.; Yan, H.; Huang, X.; Nazaretski, E.; Lauer, K.; Chu, Y. S.

2016-01-01

Chondritic porous interplanetary dust particles (CP IDPs) that were not severly heated during atmospheric deceleration are the best preserved samples of the solids that condensed from the Solar protoplanetary disk, as well as pre-Solar grains thatr survived incorporation into the disk, currently available for laboratory analysis [1]. These CP IDPs never experienced the aqueous and/or thermal processing, gravitational compaction, and shock effects that overprinted the record of Solar nebula processes in meteorites.

Pyviko: an automated Python tool to design gene knockouts in complex viruses with overlapping genes.

PubMed

Taylor, Louis J; Strebel, Klaus

2017-01-07

Gene knockouts are a common tool used to study gene function in various organisms. However, designing gene knockouts is complicated in viruses, which frequently contain sequences that code for multiple overlapping genes. Designing mutants that can be traced by the creation of new or elimination of existing restriction sites further compounds the difficulty in experimental design of knockouts of overlapping genes. While software is available to rapidly identify restriction sites in a given nucleotide sequence, no existing software addresses experimental design of mutations involving multiple overlapping amino acid sequences in generating gene knockouts. Pyviko performed well on a test set of over 240,000 gene pairs collected from viral genomes deposited in the National Center for Biotechnology Information Nucleotide database, identifying a point mutation which added a premature stop codon within the first 20 codons of the target gene in 93.2% of all tested gene-overprinted gene pairs. This shows that Pyviko can be used successfully in a wide variety of contexts to facilitate the molecular cloning and study of viral overprinted genes. Pyviko is an extensible and intuitive Python tool for designing knockouts of overlapping genes. Freely available as both a Python package and a web-based interface ( http://louiejtaylor.github.io/pyViKO/ ), Pyviko simplifies the experimental design of gene knockouts in complex viruses with overlapping genes.

The role of intrusions in the formation of Irish-type mineralisation

NASA Astrophysics Data System (ADS)

McCusker, Jim; Reed, Christopher

2013-08-01

The Stonepark Prospect is located in County Limerick, south-central Ireland. Multiple zones of Zn-Pb mineralisation have been identified at Stonepark and these are approximately 5 km west of the Pallas Green Prospect. At Stonepark, the sulphide bodies are hosted within the Waulsortian Limestone and closely resemble other Irish-type deposits. The mineralisation is composed of pyrite-marcasite, sphalerite and galena with gangue Fe-dolomite and calcite cements. A key difference at Stonepark is the presence of Chadian-aged volcanic rocks (Knockroe Volcanics) that intrude into and overlie the Waulsortian Limestone. Subsequent hydrothermal brecciation of the Waulsortian Limestone and Knockroe intrusions resulted in the formation of tabular polymict breccia bodies containing mixed carbonate and clasts of intrusive rocks. These have then been overprinted by massive sulphide mineralisation. Further syn-mineralisation brecciation has overprinted the earlier breccias. Drilling has demonstrated a spatial relationship between the volume of intrusive rocks (dykes and polymict breccias) and Zn-Pb mineralisation. This association suggests that the intrusive rocks provided a mechanism for the introduction of the mineralising fluids into the breccia bodies. This is significant as to date no large controlling fault has been identified, as is seen at other Irish-type deposits. Further work is required to understand the alteration process of the intrusive rocks and how this may relate to the mineralising process.

Cryogenic expansion joint for large superconducting magnet structures

DOEpatents

Brown, Robert L.

1978-01-01

An expansion joint is provided that accommodates dimensional changes occurring during the cooldown and warm-up of large cryogenic devices such as superconducting magnet coils. Flattened tubes containing a refrigerant such as gaseous nitrogen (N.sub.2) are inserted into expansion spaces in the structure. The gaseous N.sub.2 is circulated under pressure and aids in the cooldown process while providing its primary function of accommodating differential thermal contraction and expansion in the structure. After lower temperatures are reached and the greater part of the contraction has occured, the N.sub.2 liquefies then solidifies to provide a completely rigid structure at the cryogenic operating temperatures of the device.

History-dependence of muscle slack length following contraction and stretch in the human vastus lateralis.

PubMed

Stubbs, Peter W; Walsh, Lee D; D'Souza, Arkiev; Héroux, Martin E; Bolsterlee, Bart; Gandevia, Simon C; Herbert, Robert D

2018-06-01

In reduced muscle preparations, the slack length and passive stiffness of muscle fibres have been shown to be influenced by previous muscle contraction or stretch. In human muscles, such behaviours have been inferred from measures of muscle force, joint stiffness and reflex magnitudes and latencies. Using ultrasound imaging, we directly observed that isometric contraction of the vastus lateralis muscle at short lengths reduces the slack lengths of the muscle-tendon unit and muscle fascicles. The effect is apparent 60 s after the contraction. These observations imply that muscle contraction at short lengths causes the formation of bonds which reduce the effective length of structures that generate passive tension in muscles. In reduced muscle preparations, stretch and muscle contraction change the properties of relaxed muscle fibres. In humans, effects of stretch and contraction on properties of relaxed muscles have been inferred from measurements of time taken to develop force, joint stiffness and reflex latencies. The current study used ultrasound imaging to directly observe the effects of stretch and contraction on muscle-tendon slack length and fascicle slack length of the human vastus lateralis muscle in vivo. The muscle was conditioned by (a) strong isometric contractions at long muscle-tendon lengths, (b) strong isometric contractions at short muscle-tendon lengths, (c) weak isometric contractions at long muscle-tendon lengths and (d) slow stretches. One minute after conditioning, ultrasound images were acquired from the relaxed muscle as it was slowly lengthened through its physiological range. The ultrasound image sequences were used to identify muscle-tendon slack angles and fascicle slack lengths. Contraction at short muscle-tendon lengths caused a mean 13.5 degree (95% CI 11.8-15.0 degree) shift in the muscle-tendon slack angle towards shorter muscle-tendon lengths, and a mean 5 mm (95% CI 2-8 mm) reduction in fascicle slack length, compared to the other conditions. A supplementary experiment showed the effect could be demonstrated if the muscle was conditioned by contraction at short lengths but not if the relaxed muscle was held at short lengths, confirming the role of muscle contraction. These observations imply that muscle contraction at short lengths causes the formation of bonds which reduce the effective length of structures that generate passive tension in muscles. © 2018 The Authors. The Journal of Physiology © 2018 The Physiological Society.

Tuning the structure of thermosensitive gold nanoparticle monolayers.

PubMed

Rezende, Camila A; Shan, Jun; Lee, Lay-Theng; Zalczer, Gilbert; Tenhu, Heikki

2009-07-23

Gold nanoparticles grafted with poly(N-isopropylacrylamide) (PNIPAM) are rendered amphiphilic and thermosensitive. When spread on the surface of water, they form stable Langmuir monolayers that exhibit surface plasmon resonance. Using Langmuir balance and contrast-matched neutron reflectivity, the detailed structural properties of these nanocomposite monolayers are revealed. At low surface coverage, the gold nanoparticles are anchored to the interface by an adsorbed PNIPAM layer that forms a thin and compact pancake structure. Upon isothermal compression (T=20 degrees C), the adsorbed layer thickens with partial desorption of polymer chains to form brush structures. Two distinct polymer conformations thus coexist: an adsorbed conformation that assures stability of the monolayer, and brush structures that dangle in the subphase. An increase in temperature to 30 degrees C results in contractions of both adsorbed and brush layers with a concomitant decrease in interparticle distance, indicating vertical as well as lateral contractions of the graft polymer layer. The reversibility of this thermal response is also shown by the contraction-expansion of the polymer layers in heating-cooling cycles. The structure of the monolayer can thus be tuned by compression and reversibly by temperature. These compression and thermally induced conformational changes are discussed in relation to optical properties.

Effects of fetal hypothyroidism on uterine smooth muscle contraction and structure of offspring rats.

PubMed

Bagheripuor, Fatemeh; Ghanbari, Mahboubeh; Piryaei, Abbas; Ghasemi, Asghar

2018-05-01

What is the central question of this study? Does fetal hypothyroidism in rats alter uterine contractions and structure in the adult offspring? What is the main finding and its importance? Our study indicated that maternal hypothyroidism during pregnancy increased gestational length and decreased litter size. In addition, maternal hypothyroidism caused delayed puberty onset, irregular uterine contractions and histological changes in the uterus in the female offspring. This model might contribute to a better understanding of the cellular and molecular mechanisms involved in uterine contractions in fetal hypothyroidism, studies which are not possible in humans, and might help to establish therapeutic methods for these disorders observed in uterine contractions. Thyroid hormones play an essential role in fetal growth. Hypothyroidism impairs reproductive function in both humans and animals. The aim of this study was to assess the effects of fetal hypothyroidism on uterine smooth muscle contraction and structure in the adult offspring. The control group of female Wistar rats consumed tap water, whereas the hypothyroid group received water containing 0.025% of 6-propyl-2-thiouracial throughout gestation from mating until delivery. Isometric contractility and histological changes in uterine tissue were evaluated in the adult female offspring. We tested the effects of carbachol (10 -10 -10 -3  m) and oxytocin (10 -13 -10 -8  m) on uterine smooth muscle contraction in the fetal hypothyroid (FH) and control groups. Compared with control uteri, carbachol induced contractions with lower amplitude in the FH group (area under the curve: 1820.0 ± 250.0 versus 1370.0 ± 125.0 a.u., control versus FH group, respectively, P < 0.001) and frequency (86.4 ± 7.3 versus 37.0 ± 6.1 a.u., P < 0.001). Likewise, after exposure to oxytocin the amplitude (6614.0 ± 492.2 versus 4793.0 ± 735.2 a.u., P < 0.001) and frequency (367.4 ± 32.0 versus 167.0 ± 39.0 a.u., P < 0.001) of uterine contractions in the FH group were significantly lower than in the control group. In addition, the thickness of the endometrium and smooth muscle layer and the cross-sectional area of the uterus were also significantly lower in the FH group. Gestational length was longer and litter size smaller in FH rats compared with control animals; FH offspring also had delayed puberty. In conclusion, thyroid hormone deficiency during pregnancy increased gestational length and decreased litter size; in the offspring, it delayed puberty onset, reduced uterine rhythmic contractions and resulted in uterine structural changes. © 2018 The Authors. Experimental Physiology © 2018 The Physiological Society.

Late Cenozoic sedimentation and volcanism during transtensional deformation in Wingate Wash and the Owlshead Mountains, Death Valley

USGS Publications Warehouse

Luckow, H.G.; Pavlis, T.L.; Serpa, L.F.; Guest, B.; Wagner, D.L.; Snee, L.; Hensley, T.M.; Korjenkov, A.

2005-01-01

New 1:24,000 scale mapping, geochemical analyses of volcanic rocks, and Ar/Ar and tephrochronology analyses of the Wingate Wash, northern Owlshead Mountain and Southern Panamint Mountain region document a complex structural history constrained by syntectonic volcanism and sedimentation. In this study, the region is divided into five structural domains with distinct, but related, histories: (1) The southern Panamint domain is a structurally intact, gently south-tilted block dominated by a middle Miocene volcanic center recognized as localized hypabyssal intrusives surrounded by proximal facies pyroclastic rocks. This Miocene volcanic sequence is an unusual alkaline volcanic assemblage ranging from trachybasalt to rhyolite, but dominated by trachyandesite. The volcanic rocks are overlain in the southwestern Panamint Mountains by a younger (Late Miocene?) fanglomerate sequence. (2) An upper Wingate Wash domain is characterized by large areas of Quaternary cover and complex overprinting of older structure by Quaternary deformation. Quaternary structures record ???N-S shortening concurrent with ???E-W extension accommodated by systems of strike-slip and thrust faults. (3) A central Wingate Wash domain contains a complex structural history that is closely tied to the stratigraphic evolution. In this domain, a middle Miocene volcanic package contains two distinct assemblages; a lower sequence dominated by alkaline pyroclastic rocks similar to the southern Panamint sequence and an upper basaltic sequence of alkaline basalt and basanites. This volcanic sequence is in turn overlain by a coarse clastic sedimentary sequence that records the unroofing of adjacent ranges and development of ???N-S trending, west-tilted fault blocks. We refer to this sedimentary sequence as the Lost Lake assemblage. (4) The lower Wingate Wash/northern Owlshead domain is characterized by a gently north-dipping stratigraphic sequence with an irregular unconformity at the base developed on granitic basement. The unconformity is locally overlain by channelized deposits of older Tertiary(?) red conglomerate, some of which predate the onset of extensive volcanism, but in most of the area is overlain by a moderately thick package of Middle Miocene trachybasalt, trachyandesitic, ash flows, lithic tuff, basaltic cinder, basanites, and dacitic pyroclastic, debris, and lahar flows with localized exposures of sedimentary rocks. The upper part of the Miocene stratigraphic sequence in this domain is comprised of coarse grained-clastic sediments that are apparently middle Miocene based on Ar/Ar dating of interbedded volcanic rocks. This sedimentary sequence, however, is lithologically indistinguishable from the structurally adjacent Late Miocene Lost Lake assemblage and a stratigraphically overlying Plio-Pleistocene alluvial fan; a relationship that handicaps tracing structures through this domain. This domain is also structurally complex and deformed by a series of northwest-southeast-striking, east-dipping, high-angle oblique, sinistral, normal faults that are cut by left-lateral strike-slip faults. The contact between the southern Panamint domain and the adjacent domains is a complex fault system that we interpret as a zone of Late Miocene distributed sinistral slip that is variably overprinted in different portions of the mapped area. The net sinistral slip across the Wingate Wash fault system is estimated at 7-9 km, based on offset of Proterozoic Crystal Springs Formation beneath the middle Miocene unconformity to as much as 15 km based on offset volcanic facies in Middle Miocene rocks. To the south of Wingate Wash, the northern Owlshead Mountains are also cut by a sinistral, northwest-dipping, oblique normal fault, (referred to as the Filtonny Fault) with significant slip that separates the Lower Wingate Wash and central Owlshead domains. The Filtonny Fault may represent a young conjugate fault to the dextral Southern Death Valley fault system and may be the northwest

The application of contraction theory to an iterative formulation of electromagnetic scattering

NASA Technical Reports Server (NTRS)

Brand, J. C.; Kauffman, J. F.

1985-01-01

Contraction theory is applied to an iterative formulation of electromagnetic scattering from periodic structures and a computational method for insuring convergence is developed. A short history of spectral (or k-space) formulation is presented with an emphasis on application to periodic surfaces. To insure a convergent solution of the iterative equation, a process called the contraction corrector method is developed. Convergence properties of previously presented iterative solutions to one-dimensional problems are examined utilizing contraction theory and the general conditions for achieving a convergent solution are explored. The contraction corrector method is then applied to several scattering problems including an infinite grating of thin wires with the solution data compared to previous works.

Gravity sliding in basinal setting, a surficial record of tectonic and geodynamic evolution; examples from the southern W. Alps and their foreland

NASA Astrophysics Data System (ADS)

Dumont, T.; Franzi, V.; Matthews, S. J.

2012-04-01

The occurrence of large-scale submarine landslides, although commonly observed in the present basins, is only exceptionally mentioned in the Alpine orogen and foreland. The southern part of the Western Alpine arc and the SE basin of France provide examples of such features which could be related with particular geodynamic events, in relation with the motion of the Iberian and Adriatic microplates : - A >50km2 slump scar formed in Aptian times at the northwestern edge of the SE France (so-called Vocontian) basin, giving a low-angle detachment surface which was onlapped by Albian hemipelagic marls (Ferry & Flandrin, 1979). The latter mark the maximum deepening stage of the basin, and the head of the scar is located over a deep-seated fault bounding the platform, which strongly suggest that sliding was caused by differential subsidence due to Middle Cretaceous extension, as a consequence of Iberia-Europe divergence. - Later on, a deep-marine erosion surface developed further down the basin over a >100km2 area (Dévoluy massif; Michard et al., 2010), which had been previously affected by Mid-Cretaceous extension. Typical inversion structures are found beneath the surface, which indicate that NS shortening overprinted the extensional pattern. The removal of up to 400m of Mesozoic sediments was controlled by gravity processes, probably triggered by the deformation of the basin floor following tectonic inversion. The overlying pelagic carbonates indicate that shortening occurred before the Campanian, which is closely comparable with the earliest stages of tectonic inversion in the Pyrenees. - The transition slope between the Paleogene Alpine flexural basin and the NW-ward propagating accretionary prism provides examples of basin floor degradation and of gravity-driven emplacement of large-scale blocks, generally regarded as thrust-sheets in the Alps. These features allow to reconstruct the early stages of the Adria-Europe collision, which strongly differ from the Oligo-Miocene dynamics and which are overprinted or crosscut by the modern orogen (Dumont et al., 2011). Theses examples show that, in different structural and geodynamic settings, detailed analysis of basin floor morphology, (re)sediments transport directions, syndepositional deformations and provenance of exotic blocks can provide useful information about the regional kinematics, which can be integrated with other datasets, i.e. tectonic, metamorphic, thermochronologic, etc. Dumont T., Schwartz S., Guillot S., Simon-Labric T., Tricart P. & Jourdan S. (2011), Structural and sedimentary records of the Oligocene revolution in the Western Alpine arc. Jour. Geodyn., in press. Ferry S. & Flandrin J. (1979), Mégabrèches de resédimentation, lacunes mécaniques et pseudo-« hard-grounds » sur la marge vocontienne au Barrémien et à l'Aptien inférieur (SE France). Géologie Alpine, 55, p. 75-92. Michard A., Dumont T., Andreani L. & Loget N. (2010), Structural and sedimentary records of the Oligocene revolution in the Western Alpine arc. Bull. Soc. Géol. Fr., 181, p. 565-581.

Differences in self-rated health by employment contract and household structure among Japanese employees: a nationwide cross-sectional study.

PubMed

Kachi, Yuko; Inoue, Mariko; Nishikitani, Mariko; Yano, Eiji

2014-01-01

The aim of this study was to examine whether the association between employment contract and self-rated health differs by household structure in a representative sample of employees in Japan. The participants were 81,441 male and 64,471 female employees aged 18-59 years who had participated in the 2010 Comprehensive Survey of Living Conditions. We assessed the interactive effect of employment contract (permanent or precarious) and household structure (couple only, couple with children, single parent, single person, or other multi-person) on fair/poor health, adjusting for covariates by using logistic regression. We then calculated the relative poverty rate by employment contract and household structure. The interaction effect was significant for women (p<0.001) but not for men (p=0.413). A higher percentage of female precarious workers who lived in single-parent households (20.2%) reported fair/poor health compared with those in other types of households (10.4-13.2%), although the prevalence of fair/poor health did not differ substantially by household structure among female permanent workers. The relative poverty rates of female precarious workers who lived in single-parent households were higher compared with those of other female workers. Our results suggest that female precarious workers are not a homogeneous group and that those living in single-parent households suffer from poor health due to low income and insufficient coverage by insurance firms and family-based safety nets.

Greenschist-Facies Pseudotachylytes and Gouge: a Microstructural Study of the Deformation Propagation at the Boundary Between Hp-Metabasite and Calcite Bearing Metasediments

NASA Astrophysics Data System (ADS)

Crispini, L.; Scambelluri, M.; Capponi, G.

2013-12-01

Recent friction experiments on calcite-bearing systems reproduce pseudotachylyte structures, that are diagnostic of dinamic calcite recrystallization related to seismic slip in the shallow crust. Here we provide the study of a pseudotachylyte (PT) bearing low angle oblique-slip fault. The fault is linked to the exhumation of Alpine HP-ophiolites and it is syn- to post-metamorphic with respect to retrograde greenschist facies metamorphism. The observed microstructures developed at the brittle-ductile transition and suggest that seismic and interseismic slip was enhanced by interaction with fluids. The fault zone is in-between high-pressure eclogite-facies metabasites (hangingwall) and calcite bearing metasediments (footwall). The mafic rocks largely consist of upper greenschist facies hornblende, albite, chlorite, epidote with relict eclogitic garnet, Na-pyroxene and rutile; metasediments correspond to calcschist and micaschist with quartz, phengite, zoisite, chlorite, calcite and relics of garnet. Key features of the oucrop are: the thickness and geometry of the PT and gouge; the multiple production of PT characterized by overprinting plastic and brittle deformation; the occurrence in footwall metasediments of mm-thick bands of finely recrystallized calcite coeval with PT development in the hangingwall. The damage zone is ca. 2 m-thick and is characterized by two black, ultra-finegrained straight and sharp Principal Slip Zones (PSZ) marked by PT. The damage zone shows a variety of fault rocks (cataclasite and ultracataclasite, gouge and PT) with multiple crosscutting relationships. Within the two main PSZ, PT occurs in 10-20 cm thick layer, in small scale injection veins and in microfractures. In the mafic hanging wall, the PT is recrystallized and does not preserve glass: it shows flow structures with subrounded, embayed and rebsorbed quartz in a fine grained matrix composed of isotropic albite + chlorite + quartz + epidote + titanite, suggesting recrystallization at ca. 270-300°C, 8-10 km of the original glass. PT show plastic deformations overprinted by shear bands and fracturing. The matrix of cataclastic layers has the same mineral assemblage as PT and clasts of recrystallised PT, to indicate polyphase PSZ formation. In the metasedimentary footwall, the original foliation is deflected parallel to the PSZ and is cut by cm-spaced shear bands parallel to PSZ. Deformation propagates in the footwall through mm-thick injections veins, shear bans, P-shears and veins. Pockets of recrystallized PT occur along the pre-existing mylonitic foliation of metasediments. Worthnote is the presence of mm-thick deformation bands (CDB) that are post-mylonitic foliation and mainly composed of fine grained calcite bounded by dissolution seams or ribbon grains of deformed calcite. CDB are characterised by subrounded embayed and rebsorbed quartz grains rimmed by new Ca-Mg amphibole, K-feldspar (90-93%K), in a dinamic recrystallized calcite 2-10 micron in size and slightly elongated. The features of the CDB suggest that these structures can be considered as diagnostic of localised deformation during coesismic slip in metasedimentary rocks.

Biomechanical characteristics of skeletal muscles and associations between running speed and contraction time in 8- to 13-year-old children.

PubMed

Završnik, Jernej; Pišot, Rado; Šimunič, Boštjan; Kokol, Peter; Blažun Vošner, Helena

2017-02-01

Objective To investigate associations between running speeds and contraction times in 8- to 13-year-old children. Method This longitudinal study analyzed tensiomyographic measurements of vastus lateralis and biceps femoris muscles' contraction times and maximum running speeds in 107 children (53 boys, 54 girls). Data were evaluated using multiple correspondence analysis. Results A gender difference existed between the vastus lateralis contraction times and running speeds. The running speed was less dependent on vastus lateralis contraction times in boys than in girls. Analysis of biceps femoris contraction times and running speeds revealed that running speeds of boys were much more structurally associated with contraction times than those of girls, for whom the association seemed chaotic. Conclusion Joint category plots showed that contraction times of biceps femoris were associated much more closely with running speed than those of the vastus lateralis muscle. These results provide insight into a new dimension of children's development.

The Interpretation Of Multiple Foliations In Metapelites: An Example From NW-Namibia

NASA Astrophysics Data System (ADS)

Passchier, C. W.

2014-12-01

Foliations in metapelites belong to the most important tools in structural geology to reconstruct deformation history and kinematics. Since foliations are easily developed and are hard to destroy, multiple foliations, associated with other structures such as folds and boudins, serve as a basis in reconstructing the tectonic history of all metamorphic terrains. Traditionally, such reconstructions assume regionally homogeneous tectonic effects producing distinct generations of structures, which are then labelled D1, D2, D3 etc. The Goantagab Domain in NW Namibia consists of Neoproterozoic pelitic and psammitic metaturbidites with only minor changes in facies, exposed over an area of 80x40km. The rocks were deformed in a transpressive Neoproterozoic to Cambrian tectonic event during the amalgamation of Gondwanaland. Five overprinting foliations can be recognised in the area, but only three are recognisable at any location and no foliation extends over the entire area. Apparently, small variations in kinematic vorticity and other kinematic parameters and in orientation of incremental strain axes lead to local foliation development and to gradients in foliation style. The similarity in field and microstructure of the different foliations, and gradations in their development make a classical approach using D1-D2-D3 labelling problematic. Since the fieldwork area is very well exposed, it is possible to determine which factors lead to local development and destruction of foliations during ongoing ductile deformation. Detailed analysis of the local foliation architecture and history is used to explore new methods in structural geology to handle complex multiple foliations in metamorphic terrains

Protracted or multiple subduction of metapelites (Rhodope UHP domain, Greece)?

NASA Astrophysics Data System (ADS)

Krohe, A.; Wawrzenitz, N. H.; Mposkos, E.; Romer, R. L.

2012-12-01

The Rhodope domain formed along the suture between the European and the Apulian/Adriatic plate, which collided in the early Tertiary (closure of the Vardar/Axios ocean). Its metamorphic history includes UHP metamorphism documented by diamond inclusions in garnet (Mposkos & Kostopoulos 2001, Perraki et al. 2006, Schmidt et al. 2010), presumably of Jurassic age, and Eocene stages of MP and HP metamorphism. The age of UHPM is still a matter of debate: U-Pb SHRIMP ages extend from 184-172 Ma (monazite in metapelites) to ca. 42 Ma with clusters at 170-160, 150-140, 80-60, 50, 42 Ma, (U-Pb SHRIMP dating of zircon from amphibolitized eclogites and metapelites). These ages are interpreted to date subsequent stages of (U)HP metamorphism and decompression (Liati et al., 2005, Hoinkes et al. 2008, Bauer et al. 2006, Krenn et al 2010). However, these ages are obviously difficult to link with the metamorphic reactions. The metamorphic history has been interpreted in different ways, reflecting: (i) successive accretion of small terranes with rapid subduction and uplift histories (e.g. Liati et al. 2005); (ii) a composite of different tectonic units varying in earlier P-T histories, assembled by shear zones that reflect tectonic erosion and differential exhumation along the plate interface and that are now erased and overprinted (Krohe and Mposkos, 2002, Mposkos et al., 2010). These interpretations imply a different kinematics of the tectonic movements at depths, mechanical processes and process rates. Additionally, a protracted polymetamorphic history of larger volumes of the Rhodope UHP domain may be considered; e.g. the Kimi complex stayed in the lower crust for ca. 50-60 Ma after exhumation of the UHP rocks to this lower crustal level (Mposkos and Krohe, 2006). To constrain a precise age of the HP granulite facies and a minimum age of UHP metamorphism, we conduct an integrated structural, petrologic and geochronological study in a metapelite from the Sidronero Complex. The mineral assemblages Grt-Ky-Bt-Pl-Kfs-Qtz-Rt and Grt-Ky-Bt-Ms-Pl-Qtz-Rt, record a HP granulite facies metamorphism followed by upper amphibolite facies. The rock is particularly well suited for studying the granulite facies metamorphism, as it contains domains that are only weakly overprinted by later metamorphic episodes. ID-TIMS U-Pb ages of single monazite grains and fractions of few grains, that are only locally patchy-zoned and associated with garnet and kyanite, plot along the concordia between 64 to 60 Ma. One date of 55 Ma might represent Pb-loss during later fluid-induced dissolution-reprecipitation, probably related to biotite growth during the amphibolite facies overprint. On the base of these data, a model is discussed, in which rocks from the upper plate and HP-rocks that have been already exhumed, were dragged again into the subduction channel by subduction erosion Bauer et al. 2006, Lithos, 29, 207-228; Hoinkes et al. 2008, 3rd IGC Oslo, UHP-4; Krenn et al 2010, Tectonics, 29, TC4001; Krohe & Mposkos, 2002, Geol. Soc. Sp. Pub. 204, 151-178; Liati, A., 2005, Contrib. Mineral. Petrol., 150, 608-630; Mposkos, & Kostopoulos, 2001, EPSL, 192, 497-506; Mposkos & Krohe, 2006. Can. J. Earth Sci., 43, 1755-1776; Mposkos et al., 2010 Proc. XIX CBGA Congress, 100, 173-178; Perraki et al., 2006, EPSL, 241, 672-685; Schmidt et al., 2010, EJM, 22, 189-198.

Using Revolving Loan Funds to Finance Energy Savings Performance Contracts in State and Local Agency Applications (Revised)

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

Booth, S.; Doris, E.; Knutson, D.

2011-07-01

This document is meant to assist state and local decision makers in understanding how the financing of energy savings performance contract projects can effectively fit into the structure of a revolving loan fund.

Contract Training Services Strategic Business Plan.

ERIC Educational Resources Information Center

Sir Sandford Fleming Coll., Peterborough (Ontario).

Recommending organizational structures and strategies to achieve growth in contract training services (CTS) at Ontario's (Canada) Fleming College, this report reviews external conditions and proposes effective college responses. Following an overview of results and a recommended organizational chart, the planning process is reviewed and a…

A Summary of the FHWA Contract Administration Techniques for Quality Enhancement Study Tour (CATQEST)

DOT National Transportation Integrated Search

1994-06-01

There is a widespread impression in the United States that roads and highway structures in Europe are generally superior to comparable facilities in the United States. The joint industry and government project, the Contract Administration Techniques ...

Chief Joseph Dam, Columbia River, Washington, Additional Units and Structural Modification Foundation Report

DTIC Science & Technology

1988-01-01

diameter companion drain holes in the area below the intake structure. The second contract, DACW67-75-C-0042, was awarded to Goodfellow Brothers, Inc. in...tolerances for bolt anchors. Subhori- zontal companion drain holes were drilled adjacent to the rock bolt holes. Negligible ground water was encountered...excavation contract was then modified so that rock excavation would not go below elevation 799 feet. The contractor installed rock bolts and companion drain

Modeling the Magnetic and Thermal Structure of Active Regions: 1st Year 1st Semi-Annual Progress Report

NASA Technical Reports Server (NTRS)

Mikic, Zoran

2003-01-01

This report covers technical progress during the first six months of the first year of NASA SR&T contract "Modeling the Magnetic and Thermal Structure of Active Regions", NASW-03008, between NASA and Science Applications International Corporation, and covers the period January 14, 2003 to July 13, 2003. Under this contract SAIC has conducted research into theoretical modeling of the properties of active regions using the MHD model.

Single particle train ordering in microchannel based on inertial and vortex effects

NASA Astrophysics Data System (ADS)

Fan, Liang-Liang; Yan, Qing; Zhe, Jiang; Zhao, Liang

2018-06-01

A new microfluidic device for microparticle focusing and ordering in a single particle train is reported. The particle focusing and ordering are based on inertial and vortex effects in a microchannel with a series of suddenly contracted and widely expanded structures on one side. In the suddenly contracted regions, particles located near the contracted structures are subjected to a strong wall-effect lift force and momentum-change-induced inertial force due to the highly curved trajectory, migrating to the straight wall. A horizontal vortex is generated downstream of the contracted structure, which prevents the particle from getting close to the wall. In the widely expanded regions, the streamline is curved and no vortex is generated. The shear-gradient lift force and the momentum-change-induced inertial force are dominant for particle lateral migration, driving particles towards the wall of the expanded structures. Eventually, particles are focused and ordered in a single particle train by the combination effects of the inertial forces and the vortex. In comparison with other single-stream particle focusing methods, this device requires no sheath flow, is easy for fabrication and operation, and can work over a wide range of Reynolds numbers from 19.1–142.9. The highly ordered particle chain could be potentially utilized in a variety of lab-chip applications, including micro-flow cytometer, imaging and droplet-based cell entrapment.

Is there lattice contraction in multicomponent metal oxides? Case study for GdVO4:Eu3+ nanoparticles

NASA Astrophysics Data System (ADS)

Yang, Liusai; Li, Liping; Zhao, Minglei; Fu, Chaochao; Li, Guangshe

2013-08-01

Metal oxide nanomaterials have been found to have great potential for diverse applications due to their unique relationships between structure and properties. Lattice expansion as particle size reduces was previously considered to be general for metal oxide nanomaterials. It is now a great challenge to see if lattice contraction could be induced by the size effect for metal oxide nanomaterials. ABO4 metal oxides (e.g., CaWO4, GdVO4, and CdWO4) are some of the most important functional materials with many applications, while such oxides at the nanoscale are never reported to show a lattice contraction. This work presents a first report on the variation from lattice expansion to lattice contraction by tuning the microstructures of GdVO4:Eu3+ nanocrystals. A hydrothermal method was adopted to synthesize GdVO4:Eu3+ nanocrystals, and then these nanoparticles were calcined at 600 ° C in air. It is found that particle size reduction led to a lattice contraction for the calcined samples, which is in contrast to the lattice expansion observed for the hydrothermally synthesized counterparts or many other metal oxide nanomaterials. In addition, the lattice symmetry of the calcined samples remained almost a constant. The results indicate that the negative surface stress was eliminated by calcination treatment, leading to a homogeneous compression process in the lattice structure of the calcined GdVO4:Eu3+ nanocrystals. Furthermore, Eu3+ was taken as a structural probe and a luminescence center to study the local environments pertinent to these structural changes and to optimize the photoluminescence performance.

The contractile basis of ameboid movement. II. Structure and contractility of motile extracts and plasmalemma-ectoplasm ghosts

PubMed Central

1976-01-01

The role of calcium and magnesium-ATP on the structure and contractility in motile extracts of Amoeba proteus and plasmalemma- ectoplasm "ghosts" of Chaos carolinensis has been investigated by correlating light and electron microscope observations with turbidity and birefringence measurements. The extract is nonmotile and contains very few F-actin filaments and myosin aggregates when prepared in the presence of both low calcium ion and ATP concentrations at an ionic strength of I = 0.05, pH 6.8. The addition of 1.0 mM magnesium chloride, 1.0 mM ATP, in the presence of a low calcium ion concentration (relaxation solution) induced the formation of some fibrous bundles of actin without contracting, whereas the addition of a micromolar concentration of calcium in addition to 1.0 mM magnesium-ATP (contraction solution) (Taylor, D. L., J. S. Condeelis, P. L. Moore, and R. D. Allen. 1973. J. Cell Biol. 59:378-394) initiated the formation of large arrays of F-actin filaments followed by contractions. Furthermore, plasmalemma-ectoplasm ghosts prepared in the relaxation solution exhibited very few straight F-actin filaments and myosin aggregates. In contrast, plasmalemmaectoplasm ghosts treated with the contraction solution contained many straight F-actin filaments and myosin aggregates. The increase in the structure of ameba cytoplasm at the endoplasm-ectoplasm interface can be explained by a combination of the transformation of actin from a less filamentous to a more structured filamentous state possibly involving the cross-linking of actin to form fibrillar arrays (see above-mentioned reference) followed by contractions of the actin and myosin along an undetermined distance of the endoplasm and/or ectoplasm. PMID:6480

Characterization of muscle contraction with second harmonic generation microscopy

NASA Astrophysics Data System (ADS)

Prent, Nicole

Muscle cells have the ability to change length and generate force due to orchestrated action of myosin nanomotors that cause sliding of actin filaments along myosin filaments in the sarcomeres, the fundamental contractile units, of myocytes. The correlated action of hundreds of sarcomeres is needed to produce the myocyte contractions. This study probes the molecular structure of the myofilaments and investigates the movement correlations between sarcomeres during contraction. In this study, second harmonic generation (SHG) microscopy is employed for imaging striated myocytes. Myosin filaments in striated myocytes inherently have a nonzero second-order susceptibility, [special characters omitted] and therefore generate efficient SHG. Employing polarization-in polarization-out (PIPO) SHG microscopy allows for the accurate determination of the characteristic ratio, [special characters omitted] in birefringent myocytes, which describes the structure of the myosin filament. Analysis shows that the b value at the centre of the myosin filament, where the nonlinear dipoles are better aligned, is slightly lower than the value at the edges of the filament, where there is more disorder in orientation of the nonlinear dipoles from the myosin heads. Forced stretching of myocytes resulted in an SHG intensity increase with the elongation of the sarcomere. SHG microscopy captured individual sarcomeres during contraction, allowing for the measurement of sarcomere length (SL) and SHG intensity (SI) fluctuations. The fluctuations also revealed higher SHG intensity in elongated sarcomeres. The sarcomere synchronization model (SSM) for contracting and quiescent myocytes was developed, and experimentally verified for three cases (isolated cardiomyocyte, embryonic chicken cardiomyocyte, and larva myocyte). During contraction, the action of SLs and SIs between neighbouring sarcomeres partially correlated, whereas in quiescent myocytes the SLs show an anti-correlation and the SIs have no correlations. The characteristic correlation coefficients and amplitudes were obtained for each case, allowing for the characterization of the synchronization of sarcomere movement during muscle contraction. These investigations constitute the basis for studying the structure and physiology of muscle cell contractions with polarization SHG microscopy. Live dynamic imaging of myocytes is applicable for contractility research, drug discovery, and as a diagnostic tool for monitoring muscular diseases.

Paleomagnetism and petrophysics of the Jänisjärvi impact structure, Russian Karelia

NASA Astrophysics Data System (ADS)

Salminen, J.; Donadini, F.; Pesonen, L. J.; Masaitis, V. L.; Naumov, M. V.

Paleomagnetic, rock magnetic, and petrophysical results are presented for impactites and target rocks from the Lake Jänisjärvi impact structure, Russian Karelia. The impactites (tagamites, suevites, and lithic breccias) are characterized by increased porosity and magnetization, which is in agreement with observations performed at other impact structures. Thermomagnetic, hysteresis, and scanning electron microscope (SEM) analysis document the presence of primary multidomain titanomagnetite with additional secondary titanomaghemite and ilmenohematite. The characteristic impact-related remanent magnetization (ChRM) direction (D = 101.5°, I = 73.1°, α95 = 6.2°) yields a pole (Lat. = 45.0°N, Long. = 76.9°E, dp = 9.9°, dm = 11.0°). Additionally, the same component is observed as an overprint on some rocks located in the vicinity of the structure, which provides proofs of its primary origin.An attempt was made to determine the ancient geomagnetic field intensity. Seven reliable results were obtained, yielding an ancient intensity of 68.7 ± 7.6 μT (corresponding to VDM of 10.3 ± 1.1 × 1022 Am2). The intensity, however, appears to be biased toward high values mainly because of the concave shape of the Arai diagrams.The new paleomagnetic data and published isotopic ages for the structure are in disagreement. According to well-defined paleomagnetic data, two possible ages for magnetization of Jänisjärvi rocks exist: 1) Late Sveconorwegian age (900-850 Myr) or 2) Late Cambrian age (˜500 Myr). However, published isotopic ages are 718 ± 5 Myr (K-Ar) and 698 ± 22 Myr (39Ar-40Ar), but such isotopic dating methods are often ambiguous for the impactites.

Organizational structure of the Croatian family practice: a longitudinal study based on routinely collected data.

PubMed

Keglević, Mladenka Vrcić; Balint, Ines; Cvetković, Ivica; Gaćina, Ana

2014-12-01

This study was undertaken with the main aim of determining the trends in the number of family doctors' (FD), gender and educational structure, working status and the number of patients per FD between 1995 and 2013. As the main source of data collection served the Croatian Health Service Yearbooks and Croatian Health Insurance Fund (CHIF) databases on practices and FDs contracting in 2013. Obtained results indicated that the number of contracted FDs increased until 2007, then decreased, and again increased until 2350 in 2013. Average number of patients on FDs list was 1987 in 2012. Less than 50% FDs were specialist in family medicine, 70.3% of them were self-employed with the CHIF contract, and 81% were women. 123 practices planned by the Network did not have contracting FD in 2013. The lack of FDs, the huge number of patients over the standard number, and the location of the missing practices within the rural communities, together make Croatian FM practices less accessible.

Vibroacoustic processes and structural variations in muscular tissue

NASA Astrophysics Data System (ADS)

Antonets, V. A.; Klochkov, B. N.; Kovaleva, E. P.

1995-03-01

This paper reviews the problems and results obtained in the course of experimental and theoretical investigations of the vibroacoustic activity of contracting muscles. Two types of such processes are examined: (1) acoustic vibrations due to the macromolecular recombinations of muscle proteins, which are responsible for the muscle contraction, and (2) acoustic vibrations associated with the finite accuracy and speed of the receptor-effector system that controls the muscle contraction. By investigating the acoustic vibrations, we examine structural recombinations (conformation variations) in macromolecules during mechanochemical reactions. Since chemical reactions of macromolecules are always accompanied by conformational recombinations, the generation mechanism, which is responsible for the contraction processes in a muscular tissue, can also be extended to other macromolecular media. Investigation of infrasound vibrations makes it possible to explore the quality and error of control for the processes in the muscle under different types of loading. Since a living body is controlled via perceptions, the latter can be quantitatively estimated by the parametess of infrasound vibrations.

Associations between muscle structure and contractile performance in seniors.

PubMed

Randhawa, Avleen; Wakeling, James M

2013-07-01

Changes in muscle structure due to aging occur in a process known as sarcopenia. These changes can alter muscle mechanics during contraction that may limit mobility in seniors. The purpose of this study was to investigate the effect of sarcopenia on muscle fascicle length, pennation and belly thickness in a contracting muscle during isokinetic movements. Fascicles within a pennate muscle shorten at a slower velocity than that of the muscle belly, in a process called belly gearing. Belly gearing may be affected by atrophy and so was also tested in these seniors. The gastrocnemii were tested using ultrasound from 10 young adults (20-40 years) and 9 seniors (70-85 years). The muscle structure was imaged during standing and maximal plantarflexion at four constant velocities on a dynamometer and torque, position and time were recorded during contractions. The muscle belly thickness and pennation in seniors were significantly lower than young adults during standing. Belly thickness, changes in pennation, the belly gearing, ankle torque and power output were all significantly lower in seniors during plantarflexion contractions of the medial gastrocnemius (MG) and lateral gastrocnemius (LG). The higher pennation observed in young adults is commonly associated with increased fascicle rotations during contraction causing an increased belly gearing. The decreased fascicle rotations in seniors resulted in reduced belly gearing but the size of this effect did not match the loss in strength or power from the muscles. Copyright © 2013 Elsevier Ltd. All rights reserved.

A transaction costs analysis of changing contractual relations in the English NHS.

PubMed

Marini, Giorgia; Street, Andrew

2007-09-01

The English National Health Service has replaced locally negotiated block contracting arrangements with a system of national prices to pay for hospital activity. This paper applies a transaction costs approach to quantify and analyse the nature of how contracting costs have changed as a consequence. Data collection was based on semi-structured interviews with key stakeholders from hospitals and Primary Care Trusts, which purchase hospital services. Replacing block contracting with activity based funding has led to lower costs of price negotiation, but these are outweighed by higher costs associated with volume control, of data collection, contract monitoring, and contract enforcement. There was consensus that the new contractual arrangements were preferable, but the benefits will have to be demonstrated formally in future.

Post-Paleogene (post-Middle Eocene-pre-Miocene) Geodynamic evolution of the Upper Cretaceous-Paleogene Basins in Central Anatolia, Turkey

NASA Astrophysics Data System (ADS)

Rojay, Bora

2017-04-01

Central Anatolia is one of the key areas on the evolution of Cretaceous-Paleogene Tethys where stratigraphy of the region is well studied. However not well linked with tectonics. The so-called "Ankara Mélange" belt (AOM) and the basins on top are important elements in the understanding of the İzmir-Ankara-Erzincan suture belt (İAES) evolution in Anatolia (Turkey) and in the evolution of Tethys in minor Asia (Turkey). Some of the basins are directly situated on top of the tectonic slices of the accretionary prism (IAES). However, some are not tectonically well explained as in the case of Haymana basin. The southern continental fragments (eg. Kütahya-Bolkardaǧ and Kırşehir blocks from Gondwana) are approaching to northern continents (Pontides of Lauriasia) where basins like Haymana, Alçı, Kırıkkale and Orhaniye extensional basins are evolved in between the closing margins of two continents. Haymana basin is an extensional basin developed under contractional regime on top of both northward subducting oceanic fragments and an approaching fragments of southern continents. Paleogene (end of Eocene) is the time where the Seas were retreated to S-SE Anatolia leaving a continental setting in Anatolia during Oligocene-Miocene. The slip data gathered from the faults cross-cutting the Paleogene Units and the fabric from Cretaceous mélanges depicts a NNW-SSE to NNE-SSW compressional stress regime operated during post-Eocene-pre-Miocene period. Lately the slip surfaces were overprinted by post-Pliocene normal faulting. Key words: fault slip data, Paleogene, NNW-SSE compression, Anatolia.

Marketing and commercialization of computational research services.

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

Toevs, J. W.

Physical and computational scientists and mathematicians in Russia's nuclear cities are turning their work toward generating profits from Western markets. Successful ventures require an understanding of the marketing of contract research as well as Western expectations regarding contract execution, quality, and performance. This paper will address fundamentals in business structure, marketing, and contract performance for organizations engaging in the marketing and commercialization of research services. Considerable emphasis will be placed on developing adequate communication within the organization.

Proceedings of a Seminar on Initial Project Management Plans for Hydrologic Engineering and Economic Analysis Held at Otter Rock, Oregon on 22-24 September 1992

DTIC Science & Technology

1992-09-24

for the fifteen remaining study sites. The total number of structures to be surveyed was estimated at 800 to 1,000. When the contract was complete...Corps of Engineers real estate appraisers or contract appraisers, should be listed as a separate task. The approximate number of structures to be...DOWNGRADING SCHEDULE Distribution of this document is unlimited. 4. PERFORMING ORGANIZATION REPORT NUMBER (S) S. MONITORING ORGANIZATION REPORT NUMBER (S

Recognising Paleoseismic Events and Slip Styles in Vein Microstructures - is Incrementality Enough?

NASA Astrophysics Data System (ADS)

Fagereng, A.; Sibson, R. H.

2008-12-01

'Subduction channels', containing highly sheared, fluid-saturated, trench-fill sediments, are commonly present along subduction thrust interfaces. These shear zones accommodate fast plate boundary slip rates (1~-~10~cm/yr) and exhibit high levels of seismicity, accomplishing slip in a broad range of styles including standard earthquakes, slow slip, non-volcanic tremor and aseismic creep. Exhumed subduction channel fault rocks provide a time-integrated record of these varied slip modes though the degree of overprinting may be considerable. The Chrystalls Beach accretionary mélange, within the Otago Schist accretion-collision assemblage, New Zealand, is analogous to an active subduction channel assemblage. It contains asymmetric lenses of sandstone, chert and minor basalt enclosed within a relatively incompetent, cleaved pelitic matrix. This assemblage has been intensely sheared in a mixed continuous/discontinuous style within a flat-lying, <~4~km thick, shear zone. Ductile structures such as folds, S/C-like structures, and asymmetric boudins and clasts formed by soft sediment deformation and pressure solution creep. An extensive anastomosing vein system can be divided into mutually cross-cutting extension fractures (V1) and slickenfibre shear veins (V2). V1 commonly cut competent lenses within the mélange, while V2 mostly follow lithological contacts. Both vein sets are predominantly elongate-blocky with 'crack-seal' extension and shear increments of 10~- ~100~μm. Little sign of wall rock alteration or heating is present adjacent to V1 veins, which likely formed by incremental hydrofracture with episodic fluid influx. Post-fracture drop in Pf promoted solute precipitation from advecting fluids. This process may reflect fracture and fluid flow in a distributed fault-fracture mesh, an often inferred mechanism of non-volcanic tremor. In contrast, wall rock alteration and pressure solution seams are common adjacent to V2 veins. Slickenfibres on these shear surfaces likely formed by relatively slow dissolution and precipitation of wall rock material, which may translate to a slip mode of rise-time intermediate between earthquakes (seconds - minutes) and aseismic creep (years - infinite). Fibres are typically ≤ 10 cm long, similar to slip observed in slow slip events (rise-time weeks - months). We propose that these veins are possible records of slow slip along weak, fluid-saturated and highly overpressured planes. No definite record of large, fast earthquakes is observed in the complex, either because the rocks never experienced such events, or because significant shear heating was inhibited by thermal pressurisation. The only record of fast events would be discrete planes of cataclasite, easily overprinted by slow interseismic material diffusion. The mélange is a record of episodic, distributed deformation over a range of time- and length-scales, which may reflect distributed seismic activity accommodated by a range of slip modes including episodic tremor and slow slip.

International best practices for negotiating 'reimbursement contracts' with price rebates from pharmaceutical companies.

PubMed

Morgan, Steven; Daw, Jamie; Thomson, Paige

2013-04-01

Reimbursement contracts, in which health insurers receive rebates from drug manufacturers instead of paying the transparent list price, are becoming increasingly common worldwide. Through interviews with policy makers in nine high-income countries, we describe the use of these contracts around the globe and identify related policy challenges and best practices. Of the nine countries surveyed, the majority routinely use confidential reimbursement contracts. This alternative to drug coverage at list prices offers benefits but is not without challenges. Payers face increased administrative costs, difficulties enforcing contracts, and reduced information about prices paid by others. Among the best practices identified, policy makers recommend establishing clear and consistent processes for negotiating contracts with relatively simple rebate structures and transparency to the public about the existence, purpose, and type of reimbursement contracts in place. Policy makers should also work to address undesirable price disparities within their countries and internationally, which may occur as a result of this new pricing paradigm.

Dynamics of prolonged salt movement in the Glückstadt Graben (NW Germany) driven by tectonic and sedimentary processes

NASA Astrophysics Data System (ADS)

Warsitzka, Michael; Kley, Jonas; Jähne-Klingberg, Fabian; Kukowski, Nina

2017-01-01

The formation of salt structures exerted a major influence on the evolution of subsidence and sedimentation patterns in the Glückstadt Graben, which is part of the Central European Basin System and comprises a post-Permian sediment thickness of up to 11 km. Driven by regional tectonics and differential loading, large salt diapirs, salt walls and salt pillows developed. The resulting salt flow significantly influenced sediment distribution in the peripheral sinks adjacent to the salt structures and overprinted the regional subsidence patterns. In this study, we investigate the geometric and temporal evolution of salt structures and subsidence patterns in the central Glückstadt Graben. Along a key geological cross section, the post-Permian strata were sequentially decompacted and restored in order to reconstruct the subsidence history of minibasins between the salt structures. The structural restoration reveals that subsidence of peripheral sinks and salt structure growth were initiated in Early to Middle Triassic time. From the Late Triassic to the Middle Jurassic, salt movement and salt structure growth never ceased, but were faster during periods of crustal extension. Following a phase from Late Jurassic to the end of the early Late Cretaceous, in which minor salt flow occurred, salt movement was renewed, particularly in the marginal parts of the Glückstadt Graben. Subsidence rates and tectonic subsidence derived from backstripping of 1D profiles reveal that especially the Early Triassic and Middle Keuper times were periods of regional extension. Three specific types of salt structures and adjacent peripheral sinks could be identified: (1) Graben centre salt walls possessing deep secondary peripheral sinks on the sides facing away from the basin centre, (2) platform salt walls, whose main peripheral sinks switched multiple times from one side of the salt wall to the other, and (3) Graben edge pillows, which show only one peripheral sink facing the basin centre.

Contracts in radiology practices: contract types and key provisions.

PubMed

Muroff, Julie A; Muroff, Lawrence R

2004-07-01

A contract between a radiology group and its physician member(s) provides the foundation for the professional relationships in a group practice. The parties are not in positions of parity; contract provisions are structured to maintain the primacy of the group over the individual members. An integration clause should be included to preclude reliance on communications that are not memorialized by the language of the contract. Precise, unambiguous terms must be used to convey the intentions of the parties. The contract should have a clear date of initiation and, if applicable, an effective date of termination. Mechanisms for termination and modification should be expressed clearly to minimize the risk of judicial interference. The method of determining and adjusting the salary and other benefits of the radiologist should be stated, as consideration is necessary to support the existence of a legal contract. The obligations of the radiologist to the practice are often stated in general terms to maximize the group's flexibility. Finally, other key clauses that are discussed in the paper should be incorporated into the contract.

Definition of ground test for verification of large space structure control

NASA Technical Reports Server (NTRS)

Glaese, John R.

1994-01-01

Under this contract, the Large Space Structure Ground Test Verification (LSSGTV) Facility at the George C. Marshall Space Flight Center (MSFC) was developed. Planning in coordination with NASA was finalized and implemented. The contract was modified and extended with several increments of funding to procure additional hardware and to continue support for the LSSGTV facility. Additional tasks were defined for the performance of studies in the dynamics, control and simulation of tethered satellites. When the LSSGTV facility development task was completed, support and enhancement activities were funded through a new competitive contract won by LCD. All work related to LSSGTV performed under NAS8-35835 has been completed and documented. No further discussion of these activities will appear in this report. This report summarizes the tether dynamics and control studies performed.

The Structure and Dynamics of the Solar Corona and Inner Heliosphere

NASA Technical Reports Server (NTRS)

Mikic, Zoran; Grebowsky, J. (Technical Monitor)

2001-01-01

This report covers technical progress during the third quarter of the second year of NASA Sun-Earth Connections Theory Program (SECTP) contract 'The Structure and Dynamics of the Solar Corona and Inner Heliosphere,' NAS5-99188, between NASA and Science Applications International Corporation, and covers the period February 16, 2001 to May 15, 2001. Under this contract SAIC and the University of California, Irvine (UCI) have conducted research into theoretical modeling of active regions, the solar corona, and the inner heliosphere, using the MHD model.In this report we summarize the accomplishments made by our group during the first seven quarters of our Sun-Earth Connection Theory Program contract. The descriptions are intended to illustrate our principal results. A full account can be found in the referenced publications.

[Myocardial contractility and hemodynamics in hypothyroidism].

PubMed

Selivonenko, V G

1977-01-01

The author determined the phasic structure of the systole of the left ventricle by the method of polycardiography and hemodynamics in 20 patients suffering from hypothyrodism. Blood plasma and erythrocyte electrolytes were examined at the same time. Patients with hypothyroidism displayed a phasic syndrome of hypodynamia and a marked correlation between the phase of the synchronous contraction, the period of ejection, the strength of contraction of the left ventricle and the electrolyte content. Sodium and magnesium produced the greatest influence on the phasic structure of the systole; potassium and calcium had a lesser effect. The heart stroke volume diminished; as to the cardiac index, expenditure of the energy of cardiac contractions directed to the maintenance of movement of 1 litre of the minute blood volume; the external work, and the peripheral vascular resistance displayed no significant change.

Control of optical systems

NASA Technical Reports Server (NTRS)

Founds, D.

1988-01-01

Some of the current and planned activities at the Air Force Systems Command in structures and controls for optical-type systems are summarized. Many of the activities are contracted to industry; one task is an in-house program which includes a hardware test program. The objective of the in-house program, referred to as the Aluminum Beam Expander Structure (ABES), is to address issues involved in on-orbit system identification. The structure, which appears similar to the LDR backup structure, is about 35 feet tall. The activity to date has been limited to acquisition of about 250 hours of test data. About 30 hours of data per excitation force is gathered in order to obtain sufficient data for a good statistical estimate of the structural parameters. The development of an Integrated Structural Modeling (ISM) computer program is being done by Boeing Aerospace Company. The objective of the contracted effort is to develop a combined optics, structures, thermal, controls, and multibody dynamics simulation code.

Using Digital Computer Field Mapping of Outcrops to Examine the Preservation of High-P Rocks During Pervasive, Retrograde Greenschist Fluid Infiltration, Tinos, Cyclades Archipelago, Greece

NASA Astrophysics Data System (ADS)

Breeding, C. M.; Ague, J. J.; Broecker, M.

2001-12-01

Digital field mapping of outcrops on the island of Tinos, Greece, was undertaken to investigate the nature of retrograde fluid infiltration during exhumation of high-P metamorphic rocks of the Attic-Cycladic blueschist belt. High-resolution digital photographs of outcrops were taken and loaded into graphics editing software on a portable, belt-mounted computer in the field. Geologic features from outcrops were drawn and labeled on the digital images using the software in real-time. The ability to simultaneously identify geologic features in outcrops and digitize those features onto digital photographs in the field allows the creation of detailed, field-verified, outcrop-scale maps that aid in geologic interpretation. During Cretaceous-Eocene subduction in the Cyclades, downgoing crustal material was metamorphosed to eclogite and blueschist facies. Subsequent Oligocene-Miocene exhumation of the high-P rocks was accompanied by pervasive, retrograde fluid infiltration resulting in nearly complete greenschist facies overprinting. On Tinos, most high-P rocks have undergone intense retrogression; however, adjacent to thick marble horizons with completely retrograded contact zones, small (sub km-scale) enclaves of high-P rocks (blueschist and minor eclogite facies) were preserved. Field observations suggest that the remnant high-P zones consist mostly of massive metabasic rocks and minor adjacent metasediments. Within the enclaves, detailed digital outcrop maps reveal that greenschist retrogression increases in intensity outward from the center, implying interaction with a fluid flowing along enclave perimeters. Permeability contrasts could not have been solely responsible for preservation of the high-P rocks, as similar rock suites distal to marble contacts were completely overprinted. We conclude that the retrograded contacts of the marble units served as high-permeability conduits for regional retrograde fluid flow. Pervasive, layer-parallel flow through metasediments would have been drawn into these more permeable flow channels. Deflections in fluid flow paths toward the high flux contacts likely caused retrograde fluids to flow around the enclaves, preserving the zones of "dry," unretrograded high-P rocks near marble horizons. Digital mapping of outcrops is a unique method for direct examination of the relationships between geologic structure, lithology, and mineral assemblage variation in the field. Outcrop mapping in the Attic-Cycladic blueschist belt has revealed that regional fluid flow along contacts can have important implications for the large-scale distribution of mineral assemblages in metamorphic terranes.

Providing structural modules with self-integrity monitoring software user's manual

NASA Technical Reports Server (NTRS)

1990-01-01

National Aeronautics and Space Administration (NASA) Contract NAS7-961 (A Small Business Innovation and Research (SBIR) contract from NASA) involved research dealing with remote structural damage detection using the concept of substructures. Several approaches were developed. The main two were: (1) the module (substructure) transfer function matrix (MTFM) approach; and (2) modal strain energy distribution method (MSEDM). Either method can be used with a global structure; however, the focus was on substructures. As part of the research contract, computer software was to be developed which would implement the developed methods. This was done and it was used to process all the finite element generated numerical data for the research. The software was written for the IBM AT personal computer. Copies of it were placed on floppy disks. This report serves as a user's manual for the two sets of damage detection software. Sections 2.0 and 3.0 discuss the use of the MTFM and MSEDM software, respectively.

Four-dimensional Printing of Liquid Crystal Elastomers.

PubMed

Ambulo, Cedric P; Burroughs, Julia J; Boothby, Jennifer M; Kim, Hyun; Shankar, M Ravi; Ware, Taylor H

2017-10-25

Three-dimensional structures capable of reversible changes in shape, i.e., four-dimensional-printed structures, may enable new generations of soft robotics, implantable medical devices, and consumer products. Here, thermally responsive liquid crystal elastomers (LCEs) are direct-write printed into 3D structures with a controlled molecular order. Molecular order is locally programmed by controlling the print path used to build the 3D object, and this order controls the stimulus response. Each aligned LCE filament undergoes 40% reversible contraction along the print direction on heating. By printing objects with controlled geometry and stimulus response, magnified shape transformations, for example, volumetric contractions or rapid, repetitive snap-through transitions, are realized.

Energy Services Company | Climate Neutral Research Campuses | NREL

Science.gov Websites

different corporate and ownership structures. While many are large engineering or equipment manufacturers Services Company Options Performance-based contracts can take different forms including guaranteed energy different financing options for energy performance contracting, please refer to page 13 of the April 2009

Contract Teamwork: A Way Out of the Ivory Tower.

ERIC Educational Resources Information Center

McMillan, Sally J.

How can teamwork be implemented effectively in university-level advertising classrooms? This paper reviews literature on the nature, structure, and function of teams and processes for managing teamwork. Based on this literature, an innovative approach to contract teamwork is introduced for use in an entry-level graduate course on integrated…

Electron-phonon interaction, transport and ultrafast processes in semiconductor microstructures

NASA Astrophysics Data System (ADS)

Sarma, Sankar D.

1992-08-01

We have fulfilled our contract obligations completely by doing theoretical research on electron-phonon interaction and transport properties in submicron semiconductor structures with the emphasis on ultrafast processes and many-body effects. Fifty-five papers have been published based on our research during the contract period.

48 CFR 1852.243-71 - Shared savings.

Code of Federal Regulations, 2010 CFR

2010-10-01

... organizational support of a contract or group of contracts. These alternatives must result in a net reduction of... organizational support which are proposed to be changed. (2) A description of the difference between the current... make any structural or organizational changes in order to implement an approved CRP. (5) Government...

From osp(1|32)⊕osp(1|32) to the M-theory superalgebra: a contraction procedure

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

Fernández, J. J., E-mail: julio.j.fernandez@hotmail.es; Izquierdo, J. M., E-mail: izquierd@fta.uva.es; Olmo, M. A. del, E-mail: olmo@fta.uva.es

We show the impossibility to obtain the D’auria–Fré-type superalgebras that allow for an underlying gauge theoretical structure of D = 11 supergravity from the superalgebra osp(1|32)⊕osp(1|32)−, by means of aWeimar-Woods contraction.

Model for PCP contracts offers right incentives for Medicare, Medicaid providers.

PubMed

1999-10-01

Consider this model for PCP contracting. Provider organizations in Medicare and Medicaid often structure arrangements with their primary care providers that set up the organizations--and the doctors--to fail. An actuary from Milliman & Robertson in Seattle illustrates how to establish the right kinds of incentives for PCPs.

Dual sources of water overprinting on the low zircon δ18O metamorphic country rocks: Disequilibrium constrained through inverse modelling of partial reequilibration

PubMed Central

Wei, Chun-Sheng; Zhao, Zi-Fu

2017-01-01

Since water is only composed of oxygen and hydrogen, δ18O and δ2H values are thus utilized to trace the origin of water(s) and quantify the water-rock interactions. While Triassic high pressure (HP) and ultrahigh pressure (UHP) metamorphic rocks across the Dabie-Sulu orogen in central-eastern China have been well documented, postcollisional magmatism driven hydrothermal systems are little known. Here we show that two sources of externally derived water interactions were revealed by oxygen isotopes for the gneissic country rocks intruded by the early Cretaceous postcollisional granitoids. Inverse modellings indicate that the degree of disequilibrium (doD) of meteoric water interactions was more evident than that of magmatic one (−65 ± 1o vs. −20 ± 2°); the partial reequilibration between quartz and alkali feldspar oxygen isotopes with magmatic water was achieved at 340 °C with a water/rock (W/R) ratio of about 1.2 for an open-hydrothermal system; two-stage meteoric water interactions were unraveled with reequilibration temperatures less than 300 °C and W/R ratios around 0.4. The lifetime of fossil magmatic hydrothermal system overprinted on the low zircon δ18O orthogneissic country rocks was estimated to maintain up to 50 thousand years (Kyr) through oxygen exchange modellings. Four-stage isotopic evolutions were proposed for the magmatic water interacted gneiss. PMID:28091552

Dating Paleogene Subduction in the Alborán Domain (Alpujárride Complex, S. Spain)

NASA Astrophysics Data System (ADS)

Williams, J. R.; Ashley, K.; Loewy, S. L.; Platt, J. P.

2016-12-01

The multimineral 87Rb/86Sr method has been used in recent studies to date subduction in high-pressure (HP) metamorphic belts of the Mediterranean region. In the Alpujárride Complex, the largest tectonic unit of the Alborán Domain, southern Spain, the timing of burial and HP metamorphism is controversial, with published 40Ar/39Ar white mica ages that range from 48Ma to 25Ma. Dating the HP event is complicated by a pervasive high-temperature (HT) metamorphic overprint (23-19Ma) associated with late-orogenic extension. We have identified 5 rock samples for 87Rb/86Sr dating which preserve a HP equilibrium assemblage: a garnet-staurolite-chloritoid schist, two calcareous Mg-chloritoid schists and two calcareous phyllites with previous 40Ar/39Ar ages of 48Ma and 41Ma. Improved constraints on the time gap between HP and HT metamorphism are important to test geodynamic models of the Alborán Domain, which range from prolonged thickening of continental lithosphere followed by extensional collapse, to punctuated subduction followed by back-arc extension. Furthermore, determining the onset and duration of HP metamorphism has broad implications for whether the Alborán Domain formed in the context of a single Alpine belt, or a separate and local accretionary setting. Lastly, this study will test the advantages and limitations of the 87Rb/86Sr method in a HP domain with a late HT overprint, a very common issue in orogenic systems.

Zircon U-Pb Ages from an Ultra-High Temperature Metapelite, Rauer Group, East Antarctica: Implications for Overprints by Grenvillian and Pan-African Events

USGS Publications Warehouse

Wang, Yanbin; Tong, Laixi; Liu, Dunyi

2007-01-01

SHRIMP U-Pb dating of zircon from an ultra-high temperature (UHT, ~1000 °C) granulite-facies metapelite from the Rauer Group, Mather Peninsula, east Antarctica, has yielded evidence for two episodes of metamorphic zircon growth, at ~1.00 Ga and ~530 Ma, and two episodes of magmatism in the source region for the protolith sediment, at ~2.53 and ~2.65 Ga, were identified from the zircon cores. Successive zircon growth at ~1.00 Ga and ~530 Ma records a sequence of distinct, widely spaced high-temperature metamorphic and/or anatectic events related to Grenvillian and Pan-African orogenesis. This study presents the first robust geochronological evidence for the timing of UHT metamorphism of the Rauer Group, supporting arguments that the peak UHT metamorphic event occurred at ~1.00 Ga and was overprinted by a separate high-grade event at ~530 Ma. The new age data indicate that the UHT granulites of the Rauer Group experienced a complex, multi-stage tectonothermal history, which cannot simply be explained via a single Pan-African (~500 Ma) high-grade tectonic event. This is critical in understanding the role of the eastern Prydz Bay region during the assembly of the east Gondwana supercontinent, and the newly recognized inherited Archaean ages (~2.53 and ~2.65 Ga) suggest a close tectonic relationship between the Rauer Group and the adjacent Archaean of the Vestfold Hills

Multi-Task Project to Provide Research Support for Human Research and Engineering Goals Identified by the Army

DTIC Science & Technology

2009-06-01

Jefferson City, MO Phone:573-681-5126 E-mail: rooneyi(a>lincolnu.edu Principle Investigators for contract’s 5 Task Areas: Task I : James Rooney...identified Tasks all structured within a single contract. This contract contained Five Task areas: Task I was an administrative task; Task II-V were...Manager’s Overview of the Report (Task I ) 3. Summary Final Budget Invoice and Budget unspent balance 4. Technical Reports of the Research Tasks (II - V

An efficient matrix-matrix multiplication based antisymmetric tensor contraction engine for general order coupled cluster.

PubMed

Hanrath, Michael; Engels-Putzka, Anna

2010-08-14

In this paper, we present an efficient implementation of general tensor contractions, which is part of a new coupled-cluster program. The tensor contractions, used to evaluate the residuals in each coupled-cluster iteration are particularly important for the performance of the program. We developed a generic procedure, which carries out contractions of two tensors irrespective of their explicit structure. It can handle coupled-cluster-type expressions of arbitrary excitation level. To make the contraction efficient without loosing flexibility, we use a three-step procedure. First, the data contained in the tensors are rearranged into matrices, then a matrix-matrix multiplication is performed, and finally the result is backtransformed to a tensor. The current implementation is significantly more efficient than previous ones capable of treating arbitrary high excitations.

Context matters in NGO-government contracting for health service delivery: a case study from Pakistan.

PubMed

Zaidi, Shehla; Mayhew, Susannah H; Cleland, John; Green, Andrew T

2012-10-01

Contracting non-governmental organizations (NGOs) for health service provision is gaining increasing importance in low- and middle-income countries. However, the role of the wider context in influencing the effectiveness of contracting is not well studied and is of relevance given that contracting has produced mixed results so far. This paper applies a policy analysis approach to examine the influence of policy and political factors on contracting origin, design and implementation. Evidence is drawn from a country case study of Pakistan involving extensive NGO contracting for human immunodeficiency virus (HIV) prevention services supported by international donor agencies. A multilevel study was conducted using 84 in-depth interviews, 22 semi-structured interviews, document review and direct observation to examine the national policy design, provincial management of contracting and local contract implementation. There were three main findings. First, contracting origin and implementation was an inherently political process affected by the wider policy context. Although in Pakistan a combination of situational events successfully managed to introduce extensive and sophisticated contracting, it ran into difficulties during implementation due to ownership and capacity issues within government. Second, wide-scale contracting was mis-matched with the capacity of local NGOs, which resulted in sub-optimal contract implementation challenging the reliance on market simulation through contracting. Third, we found that contracting can have unintended knock-on effects on both providers and purchasers. As a result of public sector contracts, NGOs became more distanced from their grounded attributes. Effects on government purchasers were more unpredictable, with greater identification with contracting in supportive governance contexts and further distancing in unsupportive contexts. A careful approach is needed in government contracting of NGOs, taking into account acceptance of contracting NGOs, local NGO capacities and potential distancing of NGOs from their traditional attributes under contracts. Political factors and knock-on effects are likely to be heightened in the sudden and aggressive use of contracting in unprepared settings.

Aspects of research and development contract terms in the bio/pharmaceutical sector.

PubMed

Banerjee, Tannista

2012-01-01

The cost of new drug development is increasing every year. Pharmaceutical companies use R&D joint ventures, mergers, and outsource different stages of pharmaceutical R&D activities for a faster and cost minimizing method of innovation. Pharmaceutical companies outsource R&D activities to independent small biotech or pharmaceutical companies that specialize in different stages of pharmaceutical R&D. This chapter examines the determinants of the payment structure of research contracts between large bio/pharmaceutical companies and specialized research firms. Determinants of R&D contracts are analyzed using detailed R&D contract data between bio/pharmaceutical companies and independent research firms for 10 years. A multinomial logit model is used in order to understand the determinants of three different types of contracts; royalty contracts, fixed payment contracts, and the mixed contracts. Under uncertainty, the likelihood of a royalty contract rises for the early stages of the research and with the patent stock of the research firm. It is more likely to observe both royalty and fixed payment if the pharmaceutical client has past contracts with the same research firm. The results also suggest that if Food and Drug Administration (FDA) is more stringent in any disease area in reviewing the new drug application, then the likelihood of signing pure royalty contract decreases. Understanding the nature of R&D contracts and the effects of FDA's behavior on the pharmaceutical R&D contract is important because these contracts not only affect the cost of new drug invention but also the quality and the rate of invention. VALUE: Results are useful for both the pharmaceutical companies and the economic/business researchers.

Calcite-graphite thermometry of the Franklin Marble, New Jersey Highlands

USGS Publications Warehouse

Peck, W.H.; Volkert, R.A.; Meredith, M.T.; Rader, E.L.

2006-01-01

We present new stable-isotope data for the Mesoproterozoic Franklin Marble from outcrops along an 80-km traverse parallel to and across strike of the structural grain of the western New Jersey Highlands. Calcite and dolomite from marble have an average ??13C of 0.35??? ?? 0.73??? PDB (n = 46) and a more limited range than other Mesoproterozoic marbles from the Adirondacks and the Canadian Grenville Province. The small range of ??13C values from the New Jersey samples is consistent with the preservation of a primary marine isotopic signature and limited postdepositional isotopic modification, except proximal to Zn or Fe ore deposits and fault zones. Fractionations between calcite and well-formed graphite (??13C[Cal-Gr]) for analyzed Franklin Marble samples average 3.31???. ?? 0.25??? (n = 34), and dolomite-graphite fractionations average 3.07??? ?? 0.30??? (n = 6). Taken together, these indicate an average temperature of 769?? ?? 43??C during metamorphism associated with the Ottawan Orogeny in the New Jersey Highlands. Thus, carbon isotope fractionations demonstrate that the Franklin Marble was metamorphosed at granulite facies conditions. Metamorphic temperatures are relatively constant for the area sampled and overprint the metamorphosed carbonatehosted Zn-Fe-Mn ore deposits. The results of this study support recent work proposing that pressure and temperature conditions during Ottawan orogenesis did not vary greatly across faults that partition the Highlands into structural blocks. ?? 2006 by The University of Chicago. All rights reserved.

A brittle-ductile high- and low-angle fault related to the Kea extensional detachment (W Cyclades., Greece)

NASA Astrophysics Data System (ADS)

Rockenschaub, M.; Grasemann, B.; Iglseder, C.; Rice, A. H. N.; Schneider, D.; Zamolyi, A.

2010-05-01

Roll-back of the African Plate within the Eurasian-African collision zone since the Oligocene/Miocene led to extension in the Cyclades along low-angle normal fault zones and exhumation of rocks from near the brittle-ductile transition zone. On the island of Kea (W Cyclades), which represents such a crustal scale low-angle fault zone with top-to-SSW kinematics, remote sensing analysis of brittle fault lineaments in the Pissis area (W Kea) demonstrates two dominant strike directions: ca. NE-SW and NW-SE. From the north of Pisses southwards, the angle between the two main fault directions changes gradually from a rhombohedral geometry (ca. 50°/130° angle between faults, with the acute angle facing westwards) to an orthogonal geometry. The aim of this study is the development of this fault system. We investigate, if this fault system is related to the Miocene extension or if it is related to a later overprinting event (e.g. the opening of the Corinth) Field observations revealed that the investigated lineaments are high-angle (50-90° dip) brittle/ductile conjugate, faults. Due to the lack of marker layers offsets could only rarely be estimated. Locally centimetre thick marble layers in the greenschists suggest a displacement gradient along the faults with a maximum offset of less than 60 cm. Large displacement gradients are associated with a pronounced ductile fault drag in the host rocks. In some instances, high-angle normal faults were observed to link kinematically with low-angle, top-to-SSW brittle/ductile shear bands. Both the high- and the low-angle faults have a component of ductile shear, which is overprinted by brittle deformation mechanisms. In thin-section, polyphase mode-2 cracks are filled mainly with calcite and quartz (ultra)cataclasites, sometimes followed by further opening with fluid-related iron-rich carbonate (ankeritic) precipitation. CL analysis reveals several generations of cements, indicating multiple phases of cataclastic deformation and fluid infiltration. Ar/Ar white mica data from Pisses constrain ductile deformation to ca. 20 Ma. Since the high-angle faults show a continuum from ductile to brittle deformation, the Ar/Ar cooling ages suggest that faulting must have occurred in the Miocene. Consequently the high-angle faulting was genetically related to the SSW-directed low-angle extensional event and does not represent a later overprint related to a different kinematic event.

Migmatization and low-pressure overprinting metamorphism as record of two pre-Cretaceous tectonic episodes in the Santander Massif of the Andean basement in northern Colombia (NW South America)

NASA Astrophysics Data System (ADS)

Zuluaga, C. A.; Amaya, S.; Urueña, C.; Bernet, M.

2017-03-01

The core of the Santander Massif in the northern Andes of Colombia is dominated by migmatitic gneisses with a < 1.71 Ga protolith and was affected by continuous interactions of oceanic plates to the west and the northwestern corner of the South American continental plate. The exposed metamorphic core of the massif offers a unique opportunity to understand the tectonic evolution of northwestern South America. We present new metamorphic petrology and geochemistry data from the Bucaramanga Gneiss in the Santander Massif to document part of this tectonic evolution from late Proterozoic to Jurassic times. Metapelitic migmatite gneiss, quartz-feldspathic gneiss, and amphibolite from the Bucaramanga Gneiss recorded metamorphic peak conditions in the range of 660-850 °C at pressures of > 7.5 kbar. Lithologies are overprinted by low-pressure metamorphism, related to extensive Jurassic intrusions and linked with growth of cordierite and equilibration of low-pressure mineral assemblages, recorded metamorphic conditions are < 750 °C and < 6.5 kbar. Observed leucosomes display significant compositional variations and can be grouped in three groups: i) Group One leucosomes with high total REE content, high LREE/HREE, and negative Eu anomaly, ii) Group Two leucosomes with low total REE, low LREE/HREE, and positive Eu anomalies, and iii) Group Three leucosomes with relatively low LREE/HREE and strong positive Eu anomaly. Geochemical data support the interpretation that Group Two leucosomes crystallized from melts originated in a partial melting event affecting mostly pelitic and quartz-feldspathic lithologies with fluid-present melting reactions. The evaluation of mesosomes (amphibolite, pelitic and quartz-feldspathic rocks) as potential protoliths or restites indicates that at least two pelitic samples of the analyzed lithologies have characteristics consistent with the occurrence of fluid-present melting reactions involving quartz and feldspar. The leucosomes produced by crystallization of modified partial melts contrast with several other leucosomes that were injected; however, in some cases the melts crystallized as injected leucosomes show consistent geochemistry with partial melting of lithologies geochemically similar to the ones observed in the unit. The migmatization and the low pressure metamorphic overprint are related here to two main tectonic events: an early Paleozoic tectonic pulse produced by subduction of the oceanic crust of the Iapetus Ocean beneath northwestern Gondwana, and an Upper Triassic to Lower Jurassic tectonic pulse produced by subduction of oceanic crust of the proto-Pacific ocean beneath western Pangaea.

Reactive oxygen species generation is not different during isometric and lengthening contractions of mouse muscle

PubMed Central

Sloboda, Darcée D.

2013-01-01

Skeletal muscles can be injured by lengthening contractions, when the muscles are stretched while activated. Lengthening contractions produce structural damage that leads to the degeneration and regeneration of damaged muscle fibers by mechanisms that have not been fully elucidated. Reactive oxygen species (ROS) generated at the time of injury may initiate degenerative or regenerative processes. In the present study we hypothesized that lengthening contractions that damage the muscle would generate more ROS than isometric contractions that do not cause damage. To test our hypothesis, we subjected muscles of mice to lengthening contractions or isometric contractions and simultaneously monitored intracellular ROS generation with the fluorescent indicator 5-(and-6)-chloromethyl-2′,7′-dichlorodihydrofluorescein (CM-DCFH), which is oxidized by ROS to form the fluorescent product CM-DCF. We found that CM-DCF fluorescence was not different during or shortly after lengthening contractions compared with isometric controls, regardless of the amount of stretch and damage that occurred during the lengthening contractions. The only exception was that after severe stretches, the increase in CM-DCF fluorescence was impaired. We conclude that lengthening contractions that damage the muscle do not generate more ROS than isometric contractions that do not cause damage. The implication is that ROS generated at the time of injury are not the initiating signals for subsequent degenerative or regenerative processes. PMID:23948772

Reactive oxygen species generation is not different during isometric and lengthening contractions of mouse muscle.

PubMed

Sloboda, Darcée D; Brooks, Susan V

2013-10-01

Skeletal muscles can be injured by lengthening contractions, when the muscles are stretched while activated. Lengthening contractions produce structural damage that leads to the degeneration and regeneration of damaged muscle fibers by mechanisms that have not been fully elucidated. Reactive oxygen species (ROS) generated at the time of injury may initiate degenerative or regenerative processes. In the present study we hypothesized that lengthening contractions that damage the muscle would generate more ROS than isometric contractions that do not cause damage. To test our hypothesis, we subjected muscles of mice to lengthening contractions or isometric contractions and simultaneously monitored intracellular ROS generation with the fluorescent indicator 5-(and-6)-chloromethyl-2',7'-dichlorodihydrofluorescein (CM-DCFH), which is oxidized by ROS to form the fluorescent product CM-DCF. We found that CM-DCF fluorescence was not different during or shortly after lengthening contractions compared with isometric controls, regardless of the amount of stretch and damage that occurred during the lengthening contractions. The only exception was that after severe stretches, the increase in CM-DCF fluorescence was impaired. We conclude that lengthening contractions that damage the muscle do not generate more ROS than isometric contractions that do not cause damage. The implication is that ROS generated at the time of injury are not the initiating signals for subsequent degenerative or regenerative processes.

Effects of plyometric and isometric training on muscle and tendon stiffness in vivo.

PubMed

Kubo, Keitaro; Ishigaki, Tomonobu; Ikebukuro, Toshihiro

2017-08-01

The purpose of this study was to compare the effects of plyometric and isometric training on tendon properties during ramp and ballistic contractions and muscle stiffness under passive and active conditions. Eleven subjects completed 12 weeks (3 days/week) of a unilateral training program for the plantar flexors. They performed plyometric training on one side (PLY) and isometric training on the other side (ISO). Active muscle stiffness in the medial gastrocnemius muscle was calculated according to changes in estimated muscle force and fascicle length during fast stretching after submaximal isometric contractions. Passive muscle stiffness was also calculated from estimated passive muscle force and fascicle length during slow passive stretching. Stiffness and hysteresis of tendon structures were measured using ultrasonography during ramp and ballistic contractions. Passive muscle stiffness and tendon hysteresis did not change for PLY or ISO Active muscle stiffness significantly increased for PLY, but not for ISO Tendon stiffness during ramp and ballistic contractions increased significantly for ISO, but not for PLY In addition, tendon elongation values at force production levels beyond 100 N during ballistic contractions increased for PLY These results suggest that plyometric training (but not isometric training) enhances the extensibility of tendon structures during ballistic contractions and active muscle stiffness during fast stretching, and these changes may be related to improved performances during stretch-shortening cycle exercises. © 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

Airway mechanics and methods used to visualize smooth muscle dynamics in vitro.

PubMed

Cooper, P R; McParland, B E; Mitchell, H W; Noble, P B; Politi, A Z; Ressmeyer, A R; West, A R

2009-10-01

Contraction of airway smooth muscle (ASM) is regulated by the physiological, structural and mechanical environment in the lung. We review two in vitro techniques, lung slices and airway segment preparations, that enable in situ ASM contraction and airway narrowing to be visualized. Lung slices and airway segment approaches bridge a gap between cell culture and isolated ASM, and whole animal studies. Imaging techniques enable key upstream events involved in airway narrowing, such as ASM cell signalling and structural and mechanical events impinging on ASM, to be investigated.

NASA Sun-Earth Connections Theory Program: The Structure and Dynamics of the Solar Corona and Inner Heliosphere

NASA Technical Reports Server (NTRS)

Mikic, Zoran; Grebowsky, Joseph M. (Technical Monitor)

2001-01-01

This report covers technical progress during the fourth quarter of the second year of NASA Sun-Earth Connections Theory Program (SECTP) contract 'The Structure and Dynamics of the Solar Corona and Inner Heliosphere,' NAS5-99188, between NASA and Science Applications International Corporation, and covers the period May 16,2001 to August 15, 2001. Under this contract SAIC and the University of California, Irvine (UCI) have conducted research into theoretical modeling of active regions, the solar corona, and the inner heliosphere, using the MHD model.

The Structure and Dynamics of the Solar Corona and Inner Heliosphere

NASA Technical Reports Server (NTRS)

Mikic, Zoran; Grebowsky, J. (Technical Monitor)

2002-01-01

This report covers technical progress during the fourth quarter of the second year of NASA Sun-Earth Connections Theory Program (SECTP) contract "The Structure and Dynamics of the Solar Corona and Inner Heliosphere," NAS5-99188, between NASA and Science Applications International Corporation (SAIC), and covers the period May 16, 2001 to August 15, 2001. Under this contract SAIC and the University of California, Irvine (UCI) have conducted research into theoretical modeling of active regions, the solar corona, and the inner heliosphere, using the MHD (magnetohydrodynamic) model.

Fluid-Structure Interaction Study on a Pre-Buckled Deformable Flat Ribbon

NASA Astrophysics Data System (ADS)

Fovargue, Lauren; Shams, Ehsan; Watterson, Amy; Corson, Dave; Filardo, Benjamin; Zimmerman, Daniel; Shan, Bob; Oberai, Assad

2015-11-01

A Fluid-Structure Interaction study is conducted for the flow over a deformable flat ribbon. This mechanism, which is called ribbon frond, maybe used as a device for pumping water and/or harvesting energy in rivers. We use a lower dimensional mathematical model, which represents the ribbon as a pre-buckled structure. The surface forces from the fluid flow, dictate the deformation of the ribbon, and the ribbon in turn imposes boundary conditions for the incompressible Navier-Stokes equations. The mesh motion is handled using an Arbitrary Lagrangian-Eulerian (ALE) scheme and the fluid-structure coupling is handled by iterating over the staggered governing equations for the structure, the fluid and the mesh. Simulations are conducted at three different free stream velocities. The results, including the frequency of oscillations, show agreement with experimental data. The vortical structures near the surface of the ribbon and its deformation are highly correlated. It is observed that the ribbon motion exhibits deviation from a harmonic motion, especially at lower free stream velocities. The behavior of the ribbon is compared to swimming animals, such as eels, in order to better understand its performance. The authors acknowledge support from ONR SBIR Phase II, contract No. N0001412C0604 and USDA, NIFA SBIR Phase I, contract No. 2013-33610-20836 and NYSERDA PON 2569, contract No. 30364.

46 CFR 190.07-90 - Vessels contracted for prior to March 1, 1968.

Code of Federal Regulations, 2010 CFR

2010-10-01

... considered satisfactory so long as they are maintained in good condition to the satisfaction of the Officer in Charge, Marine Inspection. Minor repairs and alterations may be made to the same standards as the... VESSELS CONSTRUCTION AND ARRANGEMENT Structural Fire Protection § 190.07-90 Vessels contracted for prior...

77 FR 74351 - Fees for Reviews of the Rule Enforcement Programs of Designated Contract Markets and Registered...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-14

... Budget Program Activity Codes (BPAC) system, formerly the Management Accounting Structure Codes (MASC... charges fees to designated contract markets and registered futures associations to recover the costs... notice is based upon an average of actual program costs incurred during FY 2009, 2010, and 2011. DATES...

77 FR 26672 - Fees for Reviews of the Rule Enforcement Programs of Designated Contract Markets and Registered...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-07

... Activity Codes (BPAC) system, formerly the Management Accounting Structure Codes (MASC) system, which... designated contract markets and registered futures associations to recover the costs incurred by the... average of actual program costs incurred during FY 2008, 2009, and 2010. DATES: Effective Date: Each SRO...

46 CFR 190.01-90 - Vessels contracted for prior to March 1, 1968.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Section 190.01-90 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS CONSTRUCTION AND ARRANGEMENT Hull Structure § 190.01-90 Vessels contracted for prior to March 1... and alterations may be made to the same standards as the original construction. (b) Conversions, major...

48 CFR 52.229-2 - North Carolina State and Local Sales and Use Tax.

Code of Federal Regulations, 2014 CFR

2014-10-01

..., insert the following clause in solicitations and contracts for construction to be performed in North..., means building materials, supplies, fixtures, and equipment that become a part of or are annexed to any building or structure erected, altered, or repaired under this contract. (b) If this is a fixed-price...

48 CFR 52.229-2 - North Carolina State and Local Sales and Use Tax.

Code of Federal Regulations, 2010 CFR

2010-10-01

..., insert the following clause in solicitations and contracts for construction to be performed in North..., means building materials, supplies, fixtures, and equipment that become a part of or are annexed to any building or structure erected, altered, or repaired under this contract. (b) If this is a fixed-price...

48 CFR 52.229-2 - North Carolina State and Local Sales and Use Tax.

Code of Federal Regulations, 2012 CFR

2012-10-01

..., insert the following clause in solicitations and contracts for construction to be performed in North..., means building materials, supplies, fixtures, and equipment that become a part of or are annexed to any building or structure erected, altered, or repaired under this contract. (b) If this is a fixed-price...

48 CFR 52.229-2 - North Carolina State and Local Sales and Use Tax.

Code of Federal Regulations, 2011 CFR

2011-10-01

..., insert the following clause in solicitations and contracts for construction to be performed in North..., means building materials, supplies, fixtures, and equipment that become a part of or are annexed to any building or structure erected, altered, or repaired under this contract. (b) If this is a fixed-price...

48 CFR 52.229-2 - North Carolina State and Local Sales and Use Tax.

Code of Federal Regulations, 2013 CFR

2013-10-01

..., insert the following clause in solicitations and contracts for construction to be performed in North..., means building materials, supplies, fixtures, and equipment that become a part of or are annexed to any building or structure erected, altered, or repaired under this contract. (b) If this is a fixed-price...

The Relationship between Authoritarian Leadership and Employees' Deviant Workplace Behaviors: The Mediating Effects of Psychological Contract Violation and Organizational Cynicism.

PubMed

Jiang, Hongyan; Chen, Yang; Sun, Peizhen; Yang, Jun

2017-01-01

This study investigated the relationship between authoritarian leadership and employees' deviant workplace behaviors (DWB), as well as the mediating effects of psychological contract violation and organizational cynicism. A cross-sectional survey was conducted among 391 manufacturing workers in a northern city of China. Structural equation modeling was performed to test the theory-driven models. The results showed that the relationship between authoritarian leadership and employees' DWB was mediated by organizational cynicism. Moreover, this relationship was also sequentially mediated by psychological contract violation and organizational cynicism. This research unveiled psychological contract violation and organizational cynicism as underlying mechanism that explained the link between authoritarian leadership and employees' DWB.

Recent and active tectonics of the external zone of the Northern Apennines (Italy)

NASA Astrophysics Data System (ADS)

Boccaletti, Mario; Corti, Giacomo; Martelli, Luca

2011-08-01

We present a comprehensive study of the recent and active tectonics of the external part of the Northern Apennines (Italy) by using morphotectonic, geological-structural, and stratigraphic analysis, compared with the current seismicity of the region. This analysis suggests that the external part of the Northern Apennines is characterised by presence of three major systems of Quaternary compressive structures corresponding to (1) the Apenninic watershed, (2) the Apennines-Po Plain margin (pede-Apenninic thrust front), and (3) the Emilia, Ferrara, and Adriatic Fold systems buried below the Po Plain. Geological data and interpreted seismic sections indicate a roughly N-S Quaternary deformation direction, with rates <2.5 mm/year. The shortening decreased since the Pliocene, when our data indicate compression in a NNW-SSE direction and rates up to 7 mm/year. The trend and kinematics of the structures affecting the Apennines-Po Plain margin and the Po Plain subsoil fit well the pattern of the current seismicity of the area, as well as recent GPS and geodetic levelling data, pointing to a current activity of these thrust systems controlled by an overall compressive stress field. Close to the Apenninic watershed, earthquake focal mechanisms indicate that shallow extension is associated to deep compression. The extensional events may be related to a secondary extensional stress field developing on the hangingwall of the thrust system affecting the Apenninic watershed; alternatively, this thrust system may have been recently deactivated and overprinted by active normal faulting. Deeper compressive events are related to the activity of both a major basement thrust that connects at surface with the pede-Apenninic thrust front and a major Moho structure.

Kinematics of syn- and post-exhumational shear zones at Lago di Cignana (Western Alps, Italy): constraints on the exhumation of Zermatt-Saas (ultra)high-pressure rocks and deformation along the Combin Fault and Dent Blanche Basal Thrust

NASA Astrophysics Data System (ADS)

Kirst, Frederik; Leiss, Bernd

2017-01-01

Kinematic analyses of shear zones at Lago di Cignana in the Italian Western Alps were used to constrain the structural evolution of units from the Piemont-Ligurian oceanic realm (Zermatt-Saas and Combin zones) and the Adriatic continental margin (Dent Blanche nappe) during Palaeogene syn- and post-exhumational deformation. Exhumation of Zermatt-Saas (U)HP rocks to approximately lower crustal levels at ca. 39 Ma occurred during normal-sense top-(S)E shearing under epidote-amphibolite-facies conditions. Juxtaposition with the overlying Combin zone along the Combin Fault at mid-crustal levels occurred during greenschist-facies normal-sense top-SE shearing at ca. 38 Ma. The scarcity of top-SE kinematic indicators in the hanging wall of the Combin Fault probably resulted from strain localization along the uppermost Zermatt-Saas zone and obliteration by subsequent deformation. A phase of dominant pure shear deformation around 35 Ma affected units in the direct footwall and hanging wall of the Combin Fault. It is interpreted to reflect NW-SE crustal elongation during updoming of the nappe stack as a result of underthrusting of European continental margin units and the onset of continental collision. This phase was partly accompanied and followed by ductile bulk top-NW shearing, especially at higher structural levels, which transitioned into semi-ductile to brittle normal-sense top-NW deformation due to Vanzone phase folding from ca. 32 Ma onwards. Our structural observations suggest that syn-exhumational deformation is partly preserved within units and shear zones exposed at Lago di Cignana but also that the Combin Fault and Dent Blanche Basal Thrust experienced significant post-exhumational deformation reworking and overprinting earlier structures.

Investigation of Fuselage Structure Subject to Widespread Fatigue Damage

DOT National Transportation Integrated Search

1996-01-01

This report documents the results of the "Investigation of Fuselage Structure Subject to Widespread Fatigue Damage" contract. The primary program objective was to obtain data on airplane fuselage structures subject to multiple site damage (MSD) in an...

Proposal Improvements That Work

NASA Technical Reports Server (NTRS)

Dunn, F.

1998-01-01

Rocketdyne Propulsion and Power, an operating location of Boeing in Canoga Park, California is under contract with NASA's Marshall Space Flight Center (MSFC) in Huntsville, Alabama for design, development, production, and mission support of Space Shuttle Main Engines (SSMEs). The contract was restructured in 1996 to emphasize a mission contracting environment under which Rocketdyne supports the Space Transportation System launch manifest of seven flights a year without the need for a detailed list of contract deliverables such as nozzles, turbopumps, and combustion devices. This contract structure is in line with the overall Space Shuttle program goals established by the NASA to fly safely, meet the flight manifest, and reduce cost. Rocketdyne's Contracts, Pricing, and Estimating team has worked for the past several years with representatives from MSFC, the local Defense Contract Management Command, and the DCAA to improve the quality of cost proposals to MSFC for contract changes on the SSME. The contract changes on the program result primarily from engineering change proposals for product enhancements to improve safety, maintainability, or operability in the space environment. This continuous improvement team effort has been successful in improving proposal quality, reducing cycle time, and reducing cost. Some of the principal lessons learned are highlighted here to show how proposal improvements can be implemented to enhance customer satisfaction and ensure cost proposals can be evaluated easily by external customers.

The Aegean/Cycladic and the Basin and Range Extensional Provinces - A Tectonic and Geochronologic Perspective

NASA Astrophysics Data System (ADS)

Stockli, D. F.

2017-12-01

The Aegean/Cycladic region (AC) and the Basin and Range Province (B&R) are two of the most famous Cenozoic extensional provinces and have greatly influenced our thinking about syn-convergent back-arc extension, core complex formation, syn-extensional magmatism, and kinematic transitions. They share numerous tectonic and structural similarities, such as a syn-convergent setting, previous contractional deformation, and core complex formation, but fundamental geological ambiguities remain, mainly centering around timing. The B&R affected a previously contractional belt (Sevier) and voluminous continental magmatic arc that created a pre-extensional orogenic highland. Extension was long-lived and complex, driven by both gravitational collapse and temporally distinct kinematic boundary condition changes. The B&R was also affected by massive, largely pre-extensional regional magmatic flare-ups that modified both the thermal and crustal composition. As the B&R occupies an elevated interior plateau, syn-extensional basin deposits are exclusively continental in character. In contrast, the AC is a classic marine back-arc extensional province that affected an active subduction margin with numerous accreted oceanic and continental ribbons, exhuming an early Cenozoic HP-LT subduction complex. Exhumation of the HP-LT complex, however, was accommodated both by vertical extrusion and crustal extension. Late Cenozoic extensional faulting was contemporaneous with S-ward sweeping arc magmatism and affected by little to no kinematic changes. As both the AC and B&R experienced contractional deformation during K-Cz subduction and J-K shortening, respectively, it is critical to differentiate between contractional and extensional structures and fabrics. The lack of temporal constraints hampers the reconstructions of pre-extensional structural anatomies and extensional strain magnitudes or even the attribution of structures to specific geodynamic settings. Novel methodologies in petrochronology, detrital geochronology, and high- and low-T thermochronometry allow us to elucidate pre-extensional crustal geometries, differentiate contractional from extensional fabrics, and understand the thermal and rheological evolution of these extensional provinces in a more holistic fashion.

Yuji Tonomura: a pioneer in the field of energy transduction in muscle contraction.

PubMed

Onishi, Hirofumi

2009-07-01

Late Professor Yuji Tonomura has made a great contribution in the study of energy transduction in muscle contraction. He was the investigator who first proposed that a myosin-phosphate intermediate is produced subsequently to the Michaelis-Menten complex in the pre-steady state of the myosin ATPase reaction and that it is a key intermediate for muscle contraction. Here, his proposed intermediate will be viewed from the prospective of today's understanding of actomyosin ATPase kinetics and in the context of myosin motor domain crystal structures.

Geophysical reassessment of the role of ancient crustal structures on the development of western Laurentia and Selwyn Basin, Yukon and Northwest Territories, Canada.

NASA Astrophysics Data System (ADS)

Hayward, N.

2017-12-01

The structure of the western margin of the North American craton (Laurentia) in the northern Canadian Cordillera and its role in the development of the Neoproterozoic-Early Paleozoic Selwyn Basin are reassessed through 3D inversion of a new compilation of aeromagnetic data and archival Bouguer gravity data. The region's tectonic history is obscured by partial burial beneath Selwyn Basin, and a tectonic overprint that includes terrane accretion, regional plutonism, and strike-slip faults with displacements of 100s and perhaps 1000s of kilometers. Despite the implied complexity, preliminary geological and geophysical based interpretations of the structure of the western margin of Laurentia, have been adopted with few refinements in over two decades. Regionally continuous, NE-trending, crustal lineaments, including the Fort Norman line and Leith Ridge fault, were interpreted as having had long-standing influence on the craton development, its western margin, and overlapping sedimentary basin. New results reveal limited evidence for the regional continuity of the NE-trending lineaments. Instead, models suggest that the structure of the Laurentian margin is characterised by segmentation on numerous shorter structures of varied strike. The western margin of the craton and its structures are bound by a NW-trending structure that connects with the Richardson Trough to the north and may have been active during rifting of the Misty Creek embayment. This boundary also marks the easternmost limit of both granitic intrusions in Selwyn Basin, which gravity models suggest are of greater extent than reflected on geological maps, and SEDEX occurrences. An ENE-trending structure beneath northern Selwyn Basin is interpreted as marking the southern edge of a previously unidentified cratonic promontory, akin to the Liard line that marks a transfer fault that bounds the promontory of the Macdonald Platform, south of Selwyn Basin. The ENE-trending structure is traced from the Tintina fault in the west to near to the Great Bear magmatic zone. The structure's regional continuity also limits the interpretation of a post-Cretaceous structure, inboard of the Tintina fault that could be responsible for 1000's km of dextral strike-slip ascribed to the Baja-BC terrane translation model.

Pricing structures in US coal supply contracts

NASA Astrophysics Data System (ADS)

Kacker, Kanishka

The subject of my dissertation is the study of coal procurement by electric utilities in the US over 2 decades, from 1979 to 2000. Energy markets are typically characterized by severe contracting problems. Buyers and sellers therefore employ various instruments, such as contract length or complex pricing arrangements, to restrict these problems. Relationship specific investment, wherein buyers make investments specific to their suppliers, has been advanced as a prominent explanation for contractual length. Investment decisions are however endogenous in length or pricing, making causal identification of the role of investment specificity difficult. In my first chapter, I attempt a resolution. I use the 1990 Clean Air Act Amendment as an exogenous shifter of the extent of relationship specific investment. A key feature of the Amendment's design helps me define a difference-in-difference model arguably free of the endogeneity issues discussed above. I find that the plants forced into switching - Phase I plants located in the US Midwest - are more likely to choose fixed price contracts than those that were not. Further they also write contracts of shorter terms, with the reduction being approximately 30%. Considerably little is known about the performance implications of contractual choices. These form the basis for Chapter 2. Here I find prices to be lower, by between 5% to 20% of the total transaction price, but the probability of renegotiation higher, under fixed price contracts than under escalator or cost-plus contracts. Contract choices appear consistent with a trade-off between establishing incentives ex-ante and lowering negotiation costs ex-post, with relationship specific investments in particular making such a trade-off compelling. Chapter 3 considers the regulatory environment these utilities were subject to. Both incentive based regulation as well as the restructuring of electricity generation are smaller in comparison to relationship specific investment in terms of their effects on contractual decisions. Consequently, when evaluating the effect of these reforms, ignoring the contractual structure of fuel procurement - and therefore investment specificity - leads to large and significant biases in their impacts.

48 CFR 215.404-70 - DD Form 1547, Record of Weighted Guidelines Method Application.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false DD Form 1547, Record of... TYPES CONTRACTING BY NEGOTIATION Contract Pricing 215.404-70 DD Form 1547, Record of Weighted Guidelines Method Application. Follow the procedures at PGI 215.404-70 for use of DD Form 1547 whenever a structured...

Challenges of Implementing Contract Policies for University Academics in Malawi: A Case of Mzuzu University

ERIC Educational Resources Information Center

Shawa, Lester B.; Mgomezulu, Victor Y.

2016-01-01

Utilising critical theory, we explored the causes of the conflict that arose between academic staff on fixed-term renewable contracts and university administrators at Mzuzu University in Malawi in order to draw lessons. We collected data using semi-structured, in-depth interviews and document analysis. Ten university employees were purposively…

Administering Grants, Contracts, and Funds. Evaluating and Improving Your Grants System.

ERIC Educational Resources Information Center

Bauer, David G.; Otto, Mary L.

Aspects of the grants system are examined, and information on ways to improve the structure of a grants office and sharpen staff skills are provided. Thirteen chapters deal with the following topics: the purpose of the office of grants and contract administration (e.g., the essentials of brainstorming); measuring the success of a grants system…

Training Opportunities and Employee Exhaustion in Call Centres: Mediation by Psychological Contract Fulfilment

ERIC Educational Resources Information Center

Chambel, Maria Jose; Castanheira, Filipa

2012-01-01

The aim of this study is to analyse psychological contract fulfilment as a mechanism through which training affects stress in call centres. The hypotheses were tested on a sample of 412 call centre operators, using structural equation modelling to analyse their survey responses. Our results demonstrated that training is negatively related to…

Saqqar: A 34 km diameter impact structure in Saudi Arabia

NASA Astrophysics Data System (ADS)

Kenkmann, Thomas; Afifi, Abdulkader M.; Stewart, Simon A.; Poelchau, Michael H.; Cook, Douglas J.; Neville, Allen S.

2015-11-01

Here we present the first proof of an impact origin for the Saqqar circular structure in northwestern Saudi Arabia (Neville et al. ), with an apparent diameter of 34 km, centered at 29°35'N, 38°42'E. The structure is formed in Cambrian-Devonian siliciclastics and is unconformably overlain by undeformed Cretaceous and Paleogene sediments. The age of impact is not well constrained and lies somewhere between 410 and 70 Ma. The subsurface structure is constrained by 2-D reflection seismic profiles and six drilled wells. First-order structural features are a central uplift that rises approximately 2 km above regional datums, surrounded by a ring syncline. The crater rim is defined by circumferential normal faults. The central uplift and ring syncline correspond to a Bouguer gravity high and an annular ring-like low, respectively. The wells were drilled within the central uplift, the deepest among them exceed 2 km depth. Sandstone core samples from these wells show abundant indicators of a shock metamorphic overprint. Planar deformation features (PDFs) were measured with orientations along (0001), {101¯3}, and less frequently along {101¯1} and {101¯4}. Planar fractures (PFs) predominantly occur along (0001) and {101¯1}, and are locally associated with feather features (FFs). In addition, some shocked feldspar grains and strongly deformed mica flakes were found. The recorded shock pressure ranges between 5 and 15 GPa. The preserved level of shock and the absence of an allochthonous crater fill suggest that Saqqar was eroded by 1-2 km between the Devonian and Maastrichtian. The documentation of unequivocal shock features proves the formation of the Saqqar structure by a hypervelocity impact event.

The sarcomeric cytoskeleton: from molecules to motion.

PubMed

Gautel, Mathias; Djinović-Carugo, Kristina

2016-01-01

Highly ordered organisation of striated muscle is the prerequisite for the fast and unidirectional development of force and motion during heart and skeletal muscle contraction. A group of proteins, summarised as the sarcomeric cytoskeleton, is essential for the ordered assembly of actin and myosin filaments into sarcomeres, by combining architectural, mechanical and signalling functions. This review discusses recent cell biological, biophysical and structural insight into the regulated assembly of sarcomeric cytoskeleton proteins and their roles in dissipating mechanical forces in order to maintain sarcomere integrity during passive extension and active contraction. α-Actinin crosslinks in the Z-disk show a pivot-and-rod structure that anchors both titin and actin filaments. In contrast, the myosin crosslinks formed by myomesin in the M-band are of a ball-and-spring type and may be crucial in providing stable yet elastic connections during active contractions, especially eccentric exercise. © 2016. Published by The Company of Biologists Ltd.

Autologous transplantation of bone marrow-derived mesenchymal stem cells: a promising therapeutic strategy for prevention of skin-graft contraction.

PubMed

Xu, Y; Huang, S; Fu, X

2012-07-01

Hypertrophic scars result from abnormal healing of severe burns, and are characterized by loss of the original structure and function of the skin. Transplantation of autologous split skin is the preferred treatment after scar excision; however, there will be some unavoidable degree of contraction within the grafts. To our knowledge, it is very rare that bone marrow-derived mesenchymal stem cells (BM-MSCs) have been used for the treatment of skin-graft contraction. However, in our clinics, we found that during a 2-year follow-up analysis, areas treated with autologous BM-MSCs combined with transplantation of split skin were less likely to have contraction of the skin grafts than areas treated with skin grafts alone. This result indicates that BM-MSCs may be a potential and promising treatment to prevent contraction of skin grafts. © The Author(s). CED © 2012 British Association of Dermatologists.

The petroleum explorationist's guide to contracts used in oil and gas operations

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

Mosburg, L.G. Jr.

This volume provides articles and current sample forms of contract negotiation and drafting. The contents include: An introduction to oil and gas contracts; Effective deal negotiation; General principles of contract law and negotiation; Problems and pitfalls in support agreements; Sample support agreements; Basic concept of farmout agreements; Farmout negotiation checklist; ''Area of mutual interest'' provisions, Problems and pitfalls in 'contract (minimum) depth' and 'farmout (earned) depth' provisions; Options in interests assigned and reserved; Sample 'AMI' provision; ''conventional'' and ''revenue ruling 77-176'' farmout agreement forms; the AAPL model from operating agreement; 1982 revisions to the model form; Side-by-side comparisons of themore » 1956, 1977 and 1982 model forms, 1984 (1985) COPAS accounting procedure; Tax consequences of oil and gas exploration and development, revenue ruling 77-176; Use of tax partnerships and present assignments; Also materials on gas balancing agreements: Seismic options; and Structuring considerations.« less

The Relationship between Authoritarian Leadership and Employees’ Deviant Workplace Behaviors: The Mediating Effects of Psychological Contract Violation and Organizational Cynicism

PubMed Central

Jiang, Hongyan; Chen, Yang; Sun, Peizhen; Yang, Jun

2017-01-01

This study investigated the relationship between authoritarian leadership and employees’ deviant workplace behaviors (DWB), as well as the mediating effects of psychological contract violation and organizational cynicism. A cross-sectional survey was conducted among 391 manufacturing workers in a northern city of China. Structural equation modeling was performed to test the theory-driven models. The results showed that the relationship between authoritarian leadership and employees’ DWB was mediated by organizational cynicism. Moreover, this relationship was also sequentially mediated by psychological contract violation and organizational cynicism. This research unveiled psychological contract violation and organizational cynicism as underlying mechanism that explained the link between authoritarian leadership and employees’ DWB. PMID:28536550

Comments on the Parameters and Processes that Affect the Preservation Potential and Style of Oblique-Divergent Plate Boundaries

NASA Astrophysics Data System (ADS)

Umhoefer, P. J.

2014-12-01

Oblique-divergent or transtensional zones present particular challenges in ancient belts because of the poor preservation potential of the thinned continental crust and young oceanic crust. Many oblique belts will preferentially preserve their boundary zones that lie within continents rather than the main plate boundary zone, which will be at a much lower elevation and composed of denser crust. Zones of tectonic escape or strike-slip overprinting of arcs or plateaus deform continental crust and may be better preserved. Here I highlight parameters and processes that have major effects on oblique divergent belts. Strain partitioning is common, but not ubiquitous, along and across oblique boundaries; the causes of partitioning are not always clear and make this especially vexing for work in ancient belts. Partitioning causes complexity in the patterns of structures at all scales. Inherited structures commonly determine the orientation and style of structures along oblique boundaries and can control the pattern of faults across transtensional belts. Regionally, inherited trends of arcs or other 1000-km-scale features can control boundary structures. Experiments and natural examples suggest that oblique boundary zones contain less of a record of strike-slip faulting and more extensional structures. The obliquity of divergence produces predictable families of structures that typify (i) strike-slip dominated zones (obliquity <~20°), (ii) mixed zones (~20° - ~35°), and (iii) extension dominated zones (>~35°). The combination of partitioning and mixed structures in oblique zones means that the boundaries of belts with large-magnitude strike-slip faulting will commonly preserve little of no record of that faulting history. Plate boundaries localize strain onto the main plate boundary structures from the broader plate boundary and therefore the boundary zones commonly preserve the earlier structures more than later structures, a major problem in interpreting ancient belts. Sediment input is critical in some oblique plate boundaries because these belts become more pronounced sediment sinks over time. The evolving topography of oblique boundaries means that they have great variability of sediment flux into differing parts of the system; large rivers enter these belts only in special circumstances.

Modeling the dispersion effects of contractile fibers in smooth muscles

NASA Astrophysics Data System (ADS)

Murtada, Sae-Il; Kroon, Martin; Holzapfel, Gerhard A.

2010-12-01

Micro-structurally based models for smooth muscle contraction are crucial for a better understanding of pathological conditions such as atherosclerosis, incontinence and asthma. It is meaningful that models consider the underlying mechanical structure and the biochemical activation. Hence, a simple mechanochemical model is proposed that includes the dispersion of the orientation of smooth muscle myofilaments and that is capable to capture available experimental data on smooth muscle contraction. This allows a refined study of the effects of myofilament dispersion on the smooth muscle contraction. A classical biochemical model is used to describe the cross-bridge interactions with the thin filament in smooth muscles in which calcium-dependent myosin phosphorylation is the only regulatory mechanism. A novel mechanical model considers the dispersion of the contractile fiber orientations in smooth muscle cells by means of a strain-energy function in terms of one dispersion parameter. All model parameters have a biophysical meaning and may be estimated through comparisons with experimental data. The contraction of the middle layer of a carotid artery is studied numerically. Using a tube the relationships between the internal pressure and the stretches are investigated as functions of the dispersion parameter, which implies a strong influence of the orientation of smooth muscle myofilaments on the contraction response. It is straightforward to implement this model in a finite element code to better analyze more complex boundary-value problems.

Dynamics of the central entrapped bubble during drop impact

NASA Astrophysics Data System (ADS)

Jian, Zhen; Channa, Murad Ali; Thoraval, Marie-Jean

2017-11-01

When a drop impacts onto a liquid surface, it entraps a thin central air disk. The air is then brought towards the axis of symmetry by surface tension. This contraction dynamics is very challenging to capture, due to the small length scales (a few micrometers thin air disk) and time scales (contracting in a few hundred microseconds). We use the open source two-phase flow codes Gerris and Basilisk to study this air entrapment phenomenon. The effects of liquid properties such as viscosity and surface tension, and of the impact velocity were investigated. We focus on the morphology of the contracting air disk. The bubble is expected to contract into a single spherical bubble. However, in some cases, the air can be stretched vertically by the liquid inertia and split into two smaller bubbles. The convergence of capillary waves on the air disk towards the axis of symmetry can also make it rupture at the center, thus forming a toroidal bubble. In other cases, vorticity shedding can deform the contracting bubble, leading to more complex structures. A parameter space analysis based on the Reynolds and Weber numbers was then done to classify the different regimes and explain the transitions. Full affiliation:State Key Laboratory for Strength and Vibration of Mechanical Structures,Shaanxi Key Laboratory of Environment and Control for Flight Vehicle,International Center for Applied Mechanics,School of Aerospace,Xi'an Jiaotong University.

The Western Tauern Window (Eastern Alps): Timing and Interplay of Folds and Sinistral Shear Zones as Result of South-Alpine Indentation

NASA Astrophysics Data System (ADS)

Schneider, Susanne; Rosenberg, Claudio; Hammerschmidt, Konrad

2010-05-01

The Tauern Window (TW) is the only domain within the Eastern Alps where deep crustal, Tertiary metamorphic rocks were exhumed to surface. The window is bounded by large-scale faults, partly considered to be responsible for its exhumation (e.g., Selverstone 1988, Fügenschuh 1997), and it is also cross cut internally by large-scale shear zones, whose significance in terms of type and timing of deformation, exhumation, and large-scale kinematic links is the subject of our investigation. These shear zones (Ahorn, Olperer, Greiner, Ahrntal) are widespread throughout the western TW, from the mm- to the km-scale. They are sinistral and located in the steep limbs of upright antiforms, forming a mylonitic foliation, that strikes parallel to the axial planes of these upright folds. We present new structural and geochronological data, obtained by in-situ dating of microstructurally defined syn- and postkinematic grains, to constrain the duration and termination of folding and sinistral shearing. Previous dating suggested initiation of shearing contemporaneous to nappe stacking between 32-and 30Ma, ongoing until 15Ma (Glodny et al., 2008). However, the fabric of the dated grains was not related to deformation phases defined from structural overprinting relationships, and the classical separation technique did not allow to separate synkinematic from pre- and post- kinematic grains. The northern margin of the western TW is pervasively overprinted by the Ahorn Shear Zone (Rosenberg & Schneider 2008), which shows S-side up kinematic indicators in addition to the sinistral ones, and a pronounced southward increase in metamorphic grade from lower greenschist facies to amphibolite facies conditions, within 2km. Phengites of the mylonitic foliation dated with the Rb/Sr in-situ technique, yield formation ages of 14-24Ma . The southern margin of the western TW is overprinted by the sinistral Ahrntal Fault (Schneider et al. 2009), which cuts discordantly several nappes from the Zentralgneiss to the Upper Austroalpine units. Within the Upper Penninic nappes N-side up kinematic indicators occur, in addition to the sinistral ones. Newly formed biotites of Zentralgneiss rocks have been dated with the Rb/Sr technique (Kitzig et al. 2009), yielding 18-20Ma for their formation during sinistral deformation. Fine-grained phengites from the axial plane foliation of the upright folds were dated with the K/Ar method, yielding 14-17Ma. Ar/Ar in-situ LA analyses of sinistral mylonites (Ahorn, Olperer and Greiner) yield formation ages of syn-kinematic phengites between 24-12Ma. These grains are overgrown by post-kinematic phengites of 12-9Ma. Northeast of the western TW, sinistral shear is accommodated by the brittle sinistral SEMP Fault system, whose activity has been dated to 17Ma (Peresson & Decker 1997). Several sinistral shear zones (Ahorn, Greiner, Ahrntal) of the western TW may coalesce into the SEMP Fault (e.g., Linzer et al., 2002). In the west, the Ahorn Shear Zone terminates nearly 10km east of the Brenner Fault, into a NW-striking fold belt. The Ahrntal Fault continues into the Jaufen Fault, which merges with the brittle sinistral Giudicarie Fault. Motion along the Giudicarie Fault initiated in the Miocene (Stipp et al., 2004), or already in the Oligocene (Müller et al 2001). Based on these results, a temporal, kinematic and geometric continuity between sinistral shearing along the Giudicarie Fault, along the SEMP Fault, and throughout the western TW, can be assessed. The sinistral shear zones of the western TW are kinematically linked to upright folds, hence to crustal thickening. Upright folding and sinistral shearing were active since 24Ma and terminated at 12Ma. In summary, the sinistral displacements of the Giudicarie System appear to be partitioned into upright folds and sinistral, transpressive shear zones in the western Tauern Window, both of which contribute to its exhumation. The coalescence of the sinistral shear zones into the SEMP Fault System coincides with the eastern termination of the ENE-striking upright folds, possibly indicating transfer of shortening into a strike-slip displacement. Therefore, the western TW as a whole, represents a Miocene, sinistral transpressive belt, accommodating sinistral displacements associated with South-Alpine indentation by folding and sinistral shearing, and transferring these into sinistral movements associated with lateral escape along the SEMP System, until 12 Ma.

Extinct mid-ocean ridges and insights on the influence of hotspots at divergent plate boundaries

NASA Astrophysics Data System (ADS)

MacLeod, Sarah; Dietmar Müller, R.; Williams, Simon; Matthews, Kara

2016-04-01

We review all global examples of confirmed or suspected extinct mid-ocean ridges that are preserved in present-day ocean basins. Data on their spreading rate prior to extinction, time of cessation, length of activity, bathymetric and gravity signature are analysed. This analysis identifies some differences between subgroups of extinct ridges, including microplate spreading ridges, back-arc basin ridges and large-scale mid-ocean ridges. Crustal structure of extinct ridges is evaluated using gravity inversion to seek to resolve a long-standing debate on whether the final stages of spreading leads to development of thinned or thickened crust. Most of the ridges we assess have thinner crust at their axes than their flanks, yet a small number are found to have a single segment that is overprinted by an anomalous feature such as a seamount or volcanic ridge. A more complex cessation mechanism is necessary in these cases. The location of spreading centres at their time of cessation relative to hotspots was also evaluated using a global plate reconstruction. This review provides strong evidence for the long-term interaction of spreading centres with hotspots and plate boundaries have been frequently modified within the radius of a hotspot zone of influence.

Hyperparameter Classification of Arctic Sea Ice and Snow Based on Aerial Laser Data, Passive Microwave Data and Field Data

NASA Astrophysics Data System (ADS)

Herzfeld, U. C.; Maslanik, J.; Williams, S.; Sturm, M.; Cavalieri, D.

2006-12-01

In the past year, the Arctic sea-ice cover has been shrinking at an alarming rate. Remote-sensing technologies provide opportunities for observations of the sea ice at unprecedented repetition rates and spatial resolutions. The advance of new observational technologies is not only fascinating, it also brings with it the challenge and necessity to derive adequate new geoinformatical and geomathematical methods as a basis for analysis and geophysical interpretation of new data types. Our research includes validation and analysis of NASA EOS data, development of observational instrumentation and advanced geoinformatics. In this talk we emphasize the close linkage between technological development and geoinformatics along case studies of sea-ice near Point Barrow, Alaska, based on the following data types: AMSR-E and PSR passive microwave data, RADARSAT and ERS SAR data, manually-collected snow-depth data and laser-elevation data from unmanned aerial vehicles. The hyperparameter concept is introduced to facilitate characterization and classification of the same sea-ice properties and spatial structures from these data sets, which differ with respect to spatial resolution, measured parameters and observed geophysical variables. Mathematically, this requires parameter identification in undersampled, oversampled or overprinted situations.

Basal accretion, a major mechanism for mountain building in Taiwan revealed in rock thermal history

NASA Astrophysics Data System (ADS)

Chen, Chih-Tung; Chan, Yu-Chang; Lo, Ching-Hua; Malavieille, Jacques; Lu, Chia-Yu; Tang, Jui-Ting; Lee, Yuan-Hsi

2018-02-01

Deep tectonic processes are key integral components in the evolution of mountain belts, while observations of their temporal development are generally obscured by thermal resetting, retrograde alteration and structural overprinting. Here we recorded an integrated rock time-temperature history for the first time in the pro-wedge part of the active Taiwan arc-continent collision starting from sedimentation through cleavage-forming state to its final exhumation. The integrated thermal and age results from the Raman Spectroscopy of Carbonaceous Material (RSCM) method, zircon U-Pb laser ablation dating, and in-situ40Ar/39Ar laser microprobe dating suggest that the basal accretion process was crucial to the development of the Taiwanese orogenic wedge. The basal accretion process commenced early in the mountain building history (∼6 Ma) and gradually migrated to greater depths, as constrained by persistent plate convergence and cleavage formation under nearly isothermal state at similar depths until ∼ 2.5 Ma recorded in the early-accreted units. Such development essentially contributed to mountain root growth by the increased depth of the wedge detachment and the downward wedge thickening during the incipient to full collision stages in the Taiwan mountain belt.

Magnetic properties of the remagnetized Middle-Ordovician limestones of the Ponón Trehué Formation (San Rafael Block, central-western Argentina): Insights into the Permian widespread Sanrafaelic overprint

NASA Astrophysics Data System (ADS)

Fazzito, Sabrina Y.; Rapalini, Augusto E.

2016-10-01

The widespread Sanrafaelic remagnetization reset most of the early Cambrian to mid-Ordovician carbonate platform of the Argentine Precordillera and the calcareous units of the San Rafael Block. We conducted a detailed rock-magnetic study on the Middle-Ordovician limestones of the Ponón Trehué Formation at both limbs of a tight anticline exposed in the San Rafael Block (Mendoza province, central-western Argentina) that are carriers of a syntectonic magnetization of Permian age. We found that the magnetic overprint in the Ponón Trehué Formation is carried by both pyrrhotite and magnetite, with goethite and subordinate haematite likely related to weathering. Hysteresis parameters, frequency dependence of magnetic susceptibility, Cisowski and modified Lowrie-Fuller tests suggest the presence of ultrafine particles of chemical origin. Demagnetization of natural remanent magnetization and of three-axis isothermal remanence confirm pyrrhotite and magnetite as important contributors to the remanence. Both minerals carry the same magnetic syntectonic component suggesting a coeval or nearly coeval remanence acquisition and therefore mineral formation. This and the results of the magnetic fabric analyses indicate an authigenic origin of the magnetic minerals during folding associated with the Sanrafaelic tectonic phase (ca. 280 Ma). Although the chemically active (oxidizing?) fluids expelled from the orogen as it developed in the early Permian is a viable explanation for the Sanrafaelic remagnetization, the role of the nearly coeval magmatism in Precordillera and the San Rafael Block remains to be properly evaluated.

Evidence and biogeochemical implications for glacially-derived sediments in an active margin cold seep

USGS Publications Warehouse

Pohlman, John W.; Riedel, Michael; Novosel, Ivana; Bauer, James E.; Canuel, Elizabeth A.; Paull, Charles K.; Coffin, Richard B.; Grabowski, Kenneth S.; Knies, David L.; Hyndman, Roy D.; Spence, George D.

2011-01-01

Delineating sediment organic matter origins and sediment accumulation rates at gas hydratebearing and hydrocarbon seeps is complicated by the microbial transfer of 13C-depleted and 14Cdepleted methane carbon into sedimentary pools. Sediment 13C and 14C measurements from four cores recovered at Bullseye vent on the northern Cascadia margin are used to identify methane carbon assimilation into different carbon pools. While the total organic carbon (TOC) is mostly unaltered and primarily terrigenous in origin, planktonic foraminifera and the bulk carbonate display evidence of methane overprinting. Mass balance models are applied to determine the extent to which methane overprinting increased the radiocarbon ages of the biogenic foraminifera. The corrected and calibrated foraminifera ages between sediment depths of 70 and 573 cm are from 14.9 to 15.9 ka BP, which coincides with the retreat of the late Quaternary Cordilleran Ice Sheet from Vancouver Island. Uniform TOC _13C values of -24.5 ± 0.5‰ from the upper 8 meters of sediment at Bullseye vent suggest all cored material is Pleistocene-derived glacimarine material deposited as the ice edge retreated landward. Bullseye vent is located within an uplifted sediment block isolated from turbidite deposition and has been a site of non-deposition since the ice sheet retreated from the shelf. Biogeochemical implications of seep sediments being dominated by aged, organic-poor (<0.4 wt% TOC) material are that methane is the primary energy source, and microbes directly and indirectly associated with the anaerobic oxidation of methane (AOM) will dominate the seep microbial community.

Equatorial origin for Lower Jurassic radiolarian chert in the Franciscan Complex, San Rafael Mountains, southern California

USGS Publications Warehouse

Hagstrum, J.T.; Murchey, B.L.; Bogar, R.S.

1996-01-01

Lower Jurassic radiolarian chert sampled at two localities in the San Rafael Mountains of southern California (???20 km north of Santa Barbara) contains four components of remanent magnetization. Components A, B???, and B are inferred to represent uplift, Miocene volcanism, and subduction/accretion overprint magnetizations, respectively. The fourth component (C), isolated between 580?? and 680??C, shows a magnetic polarity stratigraphy and is interpreted as a primary magnetization acquired by the chert during, or soon after, deposition. Both sequences are late Pliensbachian to middle Toarcian in age, and an average paleolatitude calculated from all tilt-corrected C components is 1?? ?? 3?? north or south. This result is consistent with deposition of the cherts beneath the equatorial zone of high biologic productivity and is similar to initial paleolatitudes determined for chert blocks in northern California and Mexico. This result supports our model in which deep-water Franciscan-type cherts were deposited on the Farallon plate as it moved eastward beneath the equatorial productivity high, were accreted to the continental margin at low paleolatitudes, and were subsequently distributed northward by strike-slip faulting associated with movements of the Kula, Farallon, and Pacific plates. Upper Cretaceous turbidites of the Cachuma Formation were sampled at Agua Caliente Canyon to determine a constraining paleolatitude for accretion of the Jurassic chert sequences. These apparently unaltered rocks, however, were found to be completely overprinted by the A component of magnetization. Similar in situ directions and demagnetization behaviors observed in samples of other Upper Cretaceous turbidite sequences in southern and Baja California imply that these rocks might also give unreliable results.

Modeling the evolution of a ramp-flat-ramp thrust system: A geological application of DynEarthSol2D

NASA Astrophysics Data System (ADS)

Feng, L.; Choi, E.; Bartholomew, M. J.

2013-12-01

DynEarthSol2D (available at http://bitbucket.org/tan2/dynearthsol2) is a robust, adaptive, two-dimensional finite element code that solves the momentum balance and the heat equation in Lagrangian form using unstructured meshes. Verified in a number of benchmark problems, this solver uses contingent mesh adaptivity in places where shear strain is focused (localization) and a conservative mapping assisted by marker particles to preserve phase and facies boundaries during remeshing. We apply this cutting-edge geodynamic modeling tool to the evolution of a thrust fault with a ramp-flat-ramp geometry. The overall geometry of the fault is constrained by observations in the northern part of the southern Appalachian fold and thrust belt. Brittle crust is treated as a Mohr-Coulomb plastic material. The thrust fault is a zone of a finite thickness but has a lower cohesion and friction angle than its surrounding rocks. When an intervening flat separates two distinct sequential ramps crossing different stratigraphic intervals, the thrust system will experience more complex deformations than those from a single thrust fault ramp. The resultant deformations associated with sequential ramps would exhibit a spectrum of styles, of which two end members correspond to ';overprinting' and ';interference'. Reproducing these end-member styles as well as intermediate ones, our models show that the relative importance of overprinting versus interference is a sensitive function of initial fault geometry and hanging wall displacement. We further present stress and strain histories extracted from the models. If clearly distinguishable, they will guide the interpretation of field observations on thrust faults.

Early Archean spherule layers from the Barberton Greenstone Belt, South Africa: Mineralogy and geochemistry of the spherule beds in the CT3 drill core

NASA Astrophysics Data System (ADS)

Ozdemir, Seda; Schulz, Toni; Koeberl, Christian; Reimold, Wolf Uwe; Mohr-Westheide, Tanja; Hoehnel, Desiree; Schmitt, Ralf Thomas

2017-12-01

Little is known about the Hadean and the Archean impact record on Earth. In the CT3 drill core from the Fig Tree Group of the northern Barberton Greenstone Belt, 17 spherule layer intersections occur, which, provide an outstanding new opportunity to gain insights into meteorite bombardment of the early Earth. CT3 spherules, as primary features, mostly exhibit textural patterns similar to those of the other Barberton spherule layers, but locally mineralogical and chemical compositional differences are observed, likely as a result of various degrees of alteration. The observed mineralogy of the spherule layers is of secondary origin and comprises K-feldspar, phyllosilicates, carbonates, sulfides, and oxides, with the exception of secondary Ni-Cr spinel that is of primary origin. Our petrographic investigations suggest alteration by K-metasomatism, sericitization, silicification, and carbonatization. Siderophile element contents of bulk samples show significant enrichments in Ni (up to 2 wt%) and Ir (up to 3 ppm), similar to previously studied Archean spherule layers. These values are indicative of the presence of a meteoritic component. On the other hand, lithophile and chalcophile element abundances indicate hydrothermal overprint on the CT3 samples; this may also have influenced the redistribution of the meteoritic component(s). Last, we group the CT3 spherule layers, which occur in three intervals (A, B, and C), according to their petrographic and geochemical features, which indicate evidence for at least three distinct impact events before tectonic overprint that affected the original deposits.

Palaeomagnetism of lower cretaceous tuffs from Yukon-Kuskokwim delta region, western Alaska

USGS Publications Warehouse

Globerman, B.R.; Coe, R.S.; Hoare, J.M.; Decker, J.

1983-01-01

During the past decade, the prescient arguments1-3 for the allochthoneity of large portions of southern Alaska have been corroborated by detailed geological and palaeomagnetic studies in south-central Alaska 4-9 the Alaska Peninsula10, Kodiak Island11,12 and the Prince William Sound area13 (Fig. 1). These investigations have demonstrated sizeable northward displacements for rocks of late Palaeozoic, Mesozoic, and early Tertiary age in those regions, with northward motion at times culminating in collision of the allochthonous terranes against the backstop of 'nuclear' Alaska14,15. A fundamental question is which parts of Alaska underwent significantly less latitudinal translation relative to the 'stable' North American continent, thereby serving as the 'accretionary nucleus' into which the displaced 'microplates'16 were eventually incorporated17,18? Here we present new palaeomagnetic results from tuffs and associated volcaniclastic rocks of early Cretaceous age from the Yukon-Kuskokwin delta region in western Alaska. These rocks were probably overprinted during the Cretaceous long normal polarity interval, although a remagnetization event as recent as Palaeocene cannot be ruled out. This overprint direction is not appreciably discordant from the expected late Cretaceous direction for cratonal North America. The implied absence of appreciable northward displacement for this region is consistent with the general late Mesozoic-early Tertiary tectonic pattern for Alaska, based on more definitive studies: little to no poleward displacement for central Alaska, though substantially more northward drift for the 'southern Alaska terranes' (comprising Alaska Peninsula, Kodiak Island, Prince William Sound area, and Matunuska Valley) since late Cretaceous to Palaeocene time. ?? 1983 Nature Publishing Group.

Diverse mineral compositions, textures, and metamorphic P-T conditions of the glaucophane-bearing rocks in the Tamayen mélange, Yuli belt, eastern Taiwan

NASA Astrophysics Data System (ADS)

Tsai, Chin-Ho; Iizuka, Yoshiyuki; Ernst, W. G.

2013-02-01

This paper presents new petrologic data for high-pressure, low-temperature (HP-LT) metamorphic rocks at Juisui. We reinterpret the so-called "Tamayen block" (Yang and Wang, 1985) or "Juisui block" (Liou, 1981; Beyssac et al., 2008) as a tectonic mélange. It is not a coherent sheet but rather a mixture dominated by greenschist and pelitic schist with pods of serpentinite, epidote amphibolite, and rare blueschist. Four types of glaucophane-bearing rocks are newly recognized in this mélange. Type I is in contact with greenschist lacking glaucophane and garnet. Glaucophane is present only as rare inclusions within pargasite. This type records metamorphic evolution from epidote blueschists-, epidote amphibolite-, to greenschist-facies. Type II contains characteristic zoned amphiboles from barroisite core to Mg-katophorite mantle and glaucophane rim, implying an epidote amphibolite-facies stage overprinted by an epidote blueschists-facies one. Type III includes winchite and indicates P-T conditions of about 6-8 kbar, approaching 400 °C. Type IV contains paragonite but lacks garnet; amphibole shows a Na-Ca core surrounded by a glaucophane rim. This type shows a high-pressure (?) epidote amphibolite-facies stage overprinted by an epidote blueschists-facies one. Amphibole zoning trends and mineral assemblages imply contradictory P-T paths for the four types of glaucophane-bearing rocks—consistent with the nature of a tectonic mélange. The new P-T constraints and petrologic findings differ from previous studies (Liou et al., 1975; Beyssac et al., 2008).

Hydraulic shock waves in an inclined chute contraction

NASA Astrophysics Data System (ADS)

Jan, C.-D.; Chang, C.-J.

2009-04-01

A chute contraction is a common structure used in hydraulic engineering for typical reasons such as increase of bottom slope, transition from side channel intakes to tunnel spillways, reduction of chute width due to bridges, transition structures in flood diversion works, among others. One of the significant chute contractions in Taiwan is that used in the Yuanshantzu Flood Diversion Project of Keelung River. The diversion project is designed to divert flood water from upper Keelung River into East Sea with a capasity of 1,310 cubic meters per second for mitigating the flood damage of lower part of Keelung River basin in Northern Taiwan. An inclined chute contraction is used to connect Keelung River and a diversion turnel. The inlet and outlet works of the diversion project is located at Ruifang in the Taipei County of north Taiwan. The diameter of diversion tunnel is 12 meters and the total length of tunnel is 2,484 meters. The diversion project has been completed and successfully executed many times since 2004 to lower the water level of Keelung River in typhoon seasons for avioding flooding problems in the lower part of Keelung River basin. Flow in a chute contraction has complicated flow pattern due to the existence of shock waves in it. A simple and useful calculation procedure for the maximum height and its position of shock waves is essentially needed for the preliminary design stage of a chute contraction. Hydraulic shock waves in an inclined chute contraction were experimentally and numerically investigated in this study with the consideration of the effects of sidewall deflection angle, bottom inclination angle and Froude number of approaching flow. The flow pattern of hydraulic shock waves in a chute contraction was observed. The main issue of designing chute contraction is to estimate the height and position of maximum shock wave for the consideration of freeboards. Achieving this aim, the experimental data are adopted and analyzed for the shock angle, the height of maximum shock wave and the corresponding position of maximum shock wave. The dimensionless relations for the shock angle, the height of maximum shock wave and the corresponding position of maximum shock wave are obtained by regression analysis. These empirical regression relations, basically relating to the sidewall deflection angle, bottom angle and approach Froude number, are very useful for further practical engineering applications in chute contraction design for avoiding flow overtopping.

Ultrasonic transducer for extreme temperature environments

DOEpatents

Light, Glenn M.; Cervantes, Richard A.; Alcazar, David G.

1993-03-23

An ultrasonic piezoelectric transducer that is operable in very high and very low temperatures. The transducer has a dual housing structure that isolates the expansion and contraction of the piezoelectric element from the expansion and contraction of the housing. Also, the internal components are made from materials having similar coefficients of expansion so that they do not interfere with the motion of the piezoelectric element.

Managing Contraction: An Institution Experiences Contraction. Seattle Community College District, Seattle, Washington, U.S.A.

ERIC Educational Resources Information Center

Casey, John W.

This paper presents a historical perspective on the growth of the Seattle Community College District (SCCD) from 1967 to 1980 and the period of retrenchment from 1981 to the present. First. the paper reviews the formation of the SCCD, its organizational structure, goals and objectives, and mission. Next, demographic data are presented to…

77 FR 2579 - Self-Regulatory Organizations; NASDAQ OMX PHLX LLC; Notice of Filing and Immediate Effectiveness...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-01-18

... not be, for example, two 500- contract orders or two 500-contract legs. See Rule 1064(e). See also...), and Floor QCC Orders, as defined in 1064(e). The Exchange proposes to offer a tiered rebate structure... 1064 when such members are trading in their own proprietary account. QCC Transaction Fees are included...

Major Current Issues Impacting Government Contracting and Acquisition

DTIC Science & Technology

1984-12-01

22 E . THE OUTLOOK FOR ACQUISITION-----------24 III. COMPETITION IN ACQUISITION--------------30 A. INTRODUCTION--------------------30 B... E . THE EFFECT OF COMPETITION ADVOCACY - - - 50 F. THE COMPETITION IN CONTRACTING ACT OF 1984 ----------------- 53 a. THE FUTURE OF COMPETITION ...plus a reasonable return. Between these two types of market structure, pure competition and monopoly, there exist two other fo, rrs of marketing

Cardiac function in children with premature ventricular contractions: the effect of omega-3 polyunsaturated fatty acid supplementation.

PubMed

Oner, Taliha; Ozdemir, Rahmi; Doksöz, Onder; Genc, Dildar B; Guven, Baris; Demirpence, Savas; Yilmazer, Murat M; Yozgat, Yilmaz; Mese, Timur; Tavli, Vedide

2018-07-01

Premature ventricular contractions are accepted as benign in structurally normal hearts. However, reversible cardiomyopathy can sometimes develop. Omega-3 polyunsaturated fatty acids have anti-arrhythmic properties in animals and humans.AimWe evaluated left ventricular function in children with premature ventricular contractions with normal cardiac anatomy and assessed the impact of omega-3 fatty acid supplementation on left ventricular function in a prospective trial. A total of 25 patients with premature ventricular contraction, with more than 2% premature ventricular contractions on 24-hour Holter electrocardiography, and 30 healthy patients were included into study. All patients underwent electrocardiography, left ventricular M-mode echocardiography, and myocardial performance index testing. Patients with premature ventricular contraction were given omega-3 fatty acids at a dose of 1 g/day for 3 months, and control echocardiography and 24-hour Holter electrocardiography were performed. Neither placebo nor omega-3 fatty acids were given to the control group. Compared with the values of the control group, the patients with premature ventricular contraction had significantly lower fractional shortening. The myocardial performance index decreased markedly in the patient groups. The mean heart rate and mean premature ventricular contraction percentage of Group 2 significantly decreased in comparison with their baseline values after the omega-3 supplementation. In conclusion, premature ventricular contractions can lead to systolic cardiac dysfunction in children. Omega-3 supplementation may improve cardiac function in children with premature ventricular contractions. This is the first study conducted in children to investigate the possible role of omega-3 fatty acid supplementation on treatment of premature ventricular contractions.

Long-Term Opioid Contract Use for Chronic Pain Management in Primary Care Practice. A Five Year Experience

PubMed Central

Lamb, Geoffrey C.; Neuner, Joan M.

2007-01-01

Background The use of opioid medications to manage chronic pain is complex and challenging, especially in primary care settings. Medication contracts are increasingly being used to monitor patient adherence, but little is known about the long-term outcomes of such contracts. Objective To describe the long-term outcomes of a medication contract agreement for patients receiving opioid medications in a primary care setting. Design Retrospective cohort study. Subjects All patients placed on a contract for opioid medication between 1998 and 2003 in an academic General Internal Medicine teaching clinic. Measurements Demographics, diagnoses, opiates prescribed, urine drug screens, and reasons for contract cancellation were recorded. The association of physician contract cancellation with patient factors and medication types were examined using the Chi-square test and multivariate logistic regression. Results A total of 330 patients constituting 4% of the clinic population were placed on contracts during the study period. Seventy percent were on indigent care programs. The majority had low back pain (38%) or fibromyalgia (23%). Contracts were discontinued in 37%. Only 17% were cancelled for substance abuse and noncompliance. Twenty percent discontinued contract voluntarily. Urine toxicology screens were obtained in 42% of patients of whom 38% were positive for illicit substances. Conclusions Over 60% of patients adhered to the contract agreement for opioids with a median follow-up of 22.5 months. Our experience provides insight into establishing a systematic approach to opioid administration and monitoring in primary care practices. A more structured drug testing strategy is needed to identify nonadherent patients. PMID:17372797

Monitoring elbow isometric contraction by novel wearable fabric sensing device

NASA Astrophysics Data System (ADS)

Wang, Xi; Tao, Xiaoming; So, Raymond C. H.; Shu, Lin; Yang, Bao; Li, Ying

2016-12-01

Fabric-based wearable technology is highly desirable in sports, as it is light, flexible, soft, and comfortable with little interference to normal sport activities. It can provide accurate information on the in situ deformation of muscles in a continuous and wireless manner. During elbow flexion in isometric contraction, upper arm circumference increases with the contraction of elbow flexors, and it is possible to monitor the muscles’ contraction by limb circumferential strains. This paper presents a new wireless wearable anthropometric monitoring device made from fabric strain sensors for the human upper arm. The materials, structural design and calibration of the device are presented. Using an isokinetic testing system (Biodex3®) and the fabric monitoring device simultaneously, in situ measurements were carried out on elbow flexors in isometric contraction mode with ten subjects for a set of positions. Correlations between the measured values of limb circumferential strain and normalized torque were examined, and a linear relationship was found during isometric contraction. The average correlation coefficient between them is 0.938 ± 0.050. This wearable anthropometric device thus provides a useful index, the limb circumferential strain, for upper arm muscle contraction in isometric mode.

Airway smooth muscle contraction - perspectives on past, present and future.

PubMed

Mitchell, H W

2009-10-01

Past and contemporary views of airway smooth muscle (ASM) have led to a high level of understanding of the control and intracellular regulation of force or shortening of ASM and of its possible role in airway disease. As well as the multitude of cellular mechanisms that regulate ASM contraction, a number of structural and mechanical factors, which are only present at the airway and lung level, provide overriding control over ASM. With new knowledge about the cellular physiology and biology of ASM, there is increasing need to understand how ASM contraction is regulated and expressed at these airway and system levels.

The lanthanide contraction beyond coordination chemistry

DOE PAGES

Ferru, Geoffroy; Reinhart, Benjamin; Bera, Mrinal K.; ...

2016-04-06

Lanthanide chemistry is dominated by the ‘lanthanide contraction’, which is conceptualized traditionally through coordination chemistry. Here we break this mold, presenting evidence that the lanthanide contraction manifests outside of the coordination sphere, influencing weak interactions between groups of molecules that drive mesoscale-assembly and emergent behavior in an amphiphile solution. Furthermore, changes in these weak interactions correlate with differences in lanthanide ion transport properties, suggesting new forces to leverage rare earth separation and refining. Our results show that the lanthanide contraction paradigm extends beyond the coordination sphere, influencing structure and properties usually associated with soft matter science.

A Business Case for Home Performance Contracting

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

Baechler, Michael C.; Antonopoulos, Chrissi A.; Sevigny, Maureen

This report was prepared by PNNL for the DOE Building America program. The report provides information for businesses considering entering the home performance contracting industry. Metrics discussed include industry trends and drivers, specific points of entry, business models, startup costs, and marketing strategies. The report includes detailed analysis of eight businesses around the country that have successfully entered the home performance contracting industry. Data is provided on their financial structures, program participation, marketing efforts, and staff training. This report will be distributed via the DOE Building America website, www.buildingamerica.gov. Individual case studies will also be cleared separately.

The lanthanide contraction beyond coordination chemistry

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

Ferru, Geoffroy; Reinhart, Benjamin; Bera, Mrinal K.

Lanthanide chemistry is dominated by the ‘lanthanide contraction’, which is conceptualized traditionally through coordination chemistry. Here we break this mold, presenting evidence that the lanthanide contraction manifests outside of the coordination sphere, influencing weak interactions between groups of molecules that drive mesoscale-assembly and emergent behavior in an amphiphile solution. Furthermore, changes in these weak interactions correlate with differences in lanthanide ion transport properties, suggesting new forces to leverage rare earth separation and refining. Our results show that the lanthanide contraction paradigm extends beyond the coordination sphere, influencing structure and properties usually associated with soft matter science.

The use of standard contracts in the English National Health Service: a case study analysis.

PubMed

Petsoulas, Christina; Allen, Pauline; Hughes, David; Vincent-Jones, Peter; Roberts, Jennifer

2011-07-01

The use of contracts is vital to market transactions. The introduction of market reforms in health care in the U.K. and other developed countries twenty years ago meant greater use of contracts. In the U.K., health care contracting was widely researched in the 1990s. Yet, despite the changing policy context, the subject has attracted less interest in recent years. This paper seeks to fill a gap by reporting findings from a study of contracting in the English National Health Service (NHS) after the introduction of the national standard contract in 2007. By using economic and socio-legal theories and two case studies we examine the way in which the new contract was implemented in practice and the extent to which implementation conformed to policy intentions and to our theoretical predictions. Data were collected using non-participant observation of 36 contracting meetings, 24 semi-structured interviews, and analysis of documents. We found that despite efforts to introduce a more detailed ('complete') contract, in practice, purchasers and providers often reverted to a more relational style of contracting. Frequently reliance on the NHS hierarchy proved to be indispensable; in particular, formal dispute resolution was avoided and financial risk was re-allocated in compromises that sometimes ignored contractual provisions. Serious data deficiencies and shortages of skilled personnel still caused major difficulties. We conclude that contracting for health care continues to raise serious problems, which may be exacerbated by the impending transfer of responsibility to groups of general practitioners (GPs) who generally lack experience and expertise in large-scale, secondary care contracting. Copyright © 2011 Elsevier Ltd. All rights reserved.

Structural and molecular conformation of myosin in intact muscle fibers by second harmonic generation

NASA Astrophysics Data System (ADS)

Nucciotti, V.; Stringari, C.; Sacconi, L.; Vanzi, F.; Linari, M.; Piazzesi, G.; Lombardi, V.; Pavone, F. S.

2009-02-01

Recently, the use of Second Harmonic Generation (SHG) for imaging biological samples has been explored with regard to intrinsic SHG in highly ordered biological samples. As shown by fractional extraction of proteins, myosin is the source of SHG signal in skeletal muscle. SHG is highly dependent on symmetries and provides selective information on the structural order and orientation of the emitting proteins and the dynamics of myosin molecules responsible for the mechano-chemical transduction during contraction. We characterise the polarization-dependence of SHG intensity in three different physiological states: resting, rigor and isometric tetanic contraction in a sarcomere length range between 2.0 μm and 4.0 μm. The orientation of motor domains of the myosin molecules is dependent on their physiological states and modulate the SHG signal. We can discriminate the orientation of the emitting dipoles in four different molecular conformations of myosin heads in intact fibers during isometric contraction, in resting and rigor. We estimate the contribution of the myosin motor domain to the total second order bulk susceptibility from its molecular structure and its functional conformation. We demonstrate that SHG is sensitive to the fraction of ordered myosin heads by disrupting the order of myosin heads in rigor with an ATP analog. We estimate the fraction of myosin motors generating the isometric force in the active muscle fiber from the dependence of the SHG modulation on the degree of overlap between actin and myosin filaments during an isometric contraction.

Studying dyadic structure-function relationships: a review of current modeling approaches and new insights into Ca2+ (mis)handling.

PubMed

Maleckar, Mary M; Edwards, Andrew G; Louch, William E; Lines, Glenn T

2017-01-01

Excitation-contraction coupling in cardiac myocytes requires calcium influx through L-type calcium channels in the sarcolemma, which gates calcium release through sarcoplasmic reticulum ryanodine receptors in a process known as calcium-induced calcium release, producing a myoplasmic calcium transient and enabling cardiomyocyte contraction. The spatio-temporal dynamics of calcium release, buffering, and reuptake into the sarcoplasmic reticulum play a central role in excitation-contraction coupling in both normal and diseased cardiac myocytes. However, further quantitative understanding of these cells' calcium machinery and the study of mechanisms that underlie both normal cardiac function and calcium-dependent etiologies in heart disease requires accurate knowledge of cardiac ultrastructure, protein distribution and subcellular function. As current imaging techniques are limited in spatial resolution, limiting insight into changes in calcium handling, computational models of excitation-contraction coupling have been increasingly employed to probe these structure-function relationships. This review will focus on the development of structural models of cardiac calcium dynamics at the subcellular level, orienting the reader broadly towards the development of models of subcellular calcium handling in cardiomyocytes. Specific focus will be given to progress in recent years in terms of multi-scale modeling employing resolved spatial models of subcellular calcium machinery. A review of the state-of-the-art will be followed by a review of emergent insights into calcium-dependent etiologies in heart disease and, finally, we will offer a perspective on future directions for related computational modeling and simulation efforts.

Brain surface contraction mapped in first-episode schizophrenia: a longitudinal magnetic resonance imaging study

PubMed Central

Sun, D; Stuart, GW; Jenkinson, M; Wood, SJ; McGorry, PD; Velakoulis, D; van Erp, TGM; Thompson, PM; Toga, AW; Smith, DJ; Cannon, TD; Pantelis, C

2009-01-01

Schizophrenia is associated with structural brain abnormalities, but the timing of onset and course of these changes remains unclear. Longitudinal magnetic resonance imaging (MRI) studies have demonstrated progressive brain volume decreases in patients around and after the onset of illness, although considerable discrepancies exist regarding which brain regions are affected. The anatomical pattern of these progressive changes in schizophrenia is largely unknown. In this study, MRI scans were acquired repeatedly from 16 schizophrenia patients approximately 2 years apart following their first episode of illness, and also from 14 age-matched healthy subjects. Cortical Pattern Matching, in combination with Structural Image Evaluation, using Normalisation, of Atrophy, was applied to compare the rates of cortical surface contraction between patients and controls. Surface contraction in the dorsal surfaces of the frontal lobe was significantly greater in patients with first-episode schizophrenia (FESZ) compared with healthy controls. Overall, brain surface contraction in patients and healthy controls showed similar anatomical patterns, with that of the former group exaggerated in magnitude across the entire brain surface. That the pattern of structural change in the early course of schizophrenia corresponds so closely to that associated with normal development is consistent with the hypothesis that a schizophrenia-related factor interacts with normal adolescent brain developmental processes in the pathophysiology of schizophrenia. The exaggerated progressive changes seen in patients with schizophrenia may reflect an increased rate of synaptic pruning, resulting in excessive loss of neuronal connectivity, as predicted by the late neurodevelopmental hypothesis of the illness. PMID:18607377

Why Muscle is an Efficient Shock Absorber

PubMed Central

Kopylova, Galina V.; Fernandez, Manuel; Narayanan, Theyencheri

2014-01-01

Skeletal muscles power body movement by converting free energy of ATP hydrolysis into mechanical work. During the landing phase of running or jumping some activated skeletal muscles are subjected to stretch. Upon stretch they absorb body energy quickly and effectively thus protecting joints and bones from impact damage. This is achieved because during lengthening, skeletal muscle bears higher force and has higher instantaneous stiffness than during isometric contraction, and yet consumes very little ATP. We wish to understand how the actomyosin molecules change their structure and interaction to implement these physiologically useful mechanical and thermodynamical properties. We monitored changes in the low angle x-ray diffraction pattern of rabbit skeletal muscle fibers during ramp stretch compared to those during isometric contraction at physiological temperature using synchrotron radiation. The intensities of the off-meridional layer lines and fine interference structure of the meridional M3 myosin x-ray reflection were resolved. Mechanical and structural data show that upon stretch the fraction of actin-bound myosin heads is higher than during isometric contraction. On the other hand, the intensities of the actin layer lines are lower than during isometric contraction. Taken together, these results suggest that during stretch, a significant fraction of actin-bound heads is bound non-stereo-specifically, i.e. they are disordered azimuthally although stiff axially. As the strong or stereo-specific myosin binding to actin is necessary for actin activation of the myosin ATPase, this finding explains the low metabolic cost of energy absorption by muscle during the landing phase of locomotion. PMID:24465673

Novel pentapeptide, PALAL, derived from a bony fish elicits contraction of the muscle in starfish Patiria pectinifera.

PubMed

Go, Hye-Jin; Kim, Chan-Hee; Oh, Hye Young; Park, Nam Gyu

2016-10-01

A bioactive peptide mimicking peptide-signaling molecules has been isolated from the skin extract of fish Channa argus which caused contraction of the apical muscle of a starfish Patiria pectinifera, a deuterostomian invertebrate. The primary structure of the isolated pentapeptide comprises amino acid sequence of H-Pro-Ala-Leu-Ala-Leu-OH (PALAL) with a molecular mass of 483.7 Da. Pharmacological activity of PALAL, dosage ranging from 10 -9 to 10 -5 M, revealed concentration-dependent contraction of the apical muscles of P. pectinifera and Asterias amurensis. However, PALAL was not active on the intestinal smooth muscle of the goldfish Carassius auratus and has presumably other physiological roles in fish skin. Investigation of structure-activity relationship using truncated and substituted analogs of PALAL demonstrated that H-Ala-Leu-Ala-Leu-OH was necessary and should be sufficient to constrict apical muscle of P. pectinifera. Furthermore, the second alanine residue was required to display the activity, and the fifth leucine residue was responsible for its potency. Comparison with PALAL's primary structure with those of other known bioactive peptides from fish and starfish revealed that PALAL does not have any significant homology. Consequently, PALAL is a bioactive peptide that elicits a muscle contraction in starfish, and the isolation of PALAL may lead to develop other bioactive peptides sharing its similar sequence and/or activity. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd.

Contracting in specialists for emergency obstetric care- does it work in rural India?

PubMed

Randive, Bharat; Chaturvedi, Sarika; Mistry, Nerges

2012-12-31

Contracting in private sector is promoted in developing countries facing human resources shortages as a challenge to reduce maternal mortality. This study explored provision, practice, performance, barriers to execution and views about contracting in specialists for emergency obstetric care (EmOC) in rural India. Facility survey was conducted in all secondary and tertiary public health facilities (44) in three heterogeneous districts in Maharashtra state of India. Interviews (42) were conducted with programme managers and district and block level officials and with public and private EmOC specialists. Locations of private obstetricians in the study districts were identified and mapped. Two schemes, namely Janani Suraksha Yojana and Indian Public Health standards (IPHS) provided for contracting in EmOC specialists. The IPHS provision was chosen for use mainly due to greater sum for contracting in (US $ 30/service episode vs.300 US$/month). The positions of EmOC specialists were vacant in 83% of all facilities that hence had a potential for contracting in EmOC specialists. Private specialists were contracted in at 20% such facilities. The contracting in of specialists did not greatly increase EmOC service outputs at facilities, except in facilities with determined leadership. Contracting in specialists was useful for non emergency conditions, but not for obstetric emergencies. The contracts were more of a relational nature with poor monitoring structures. Inadequate infrastructure, longer distance to private specialists, insufficient financial provision for contracting in, and poor management capacities were barriers to effective implementation of contracting in. Dependency on the private sector was a concern among public partners while the private partners viewed contracting in as an opportunity to gain experience and credibility. Density and geographic distribution of private specialists are important influencing factors in determining feasibility and use of contracting in for EmOC. Local circumstances dictate balance between introduction or expansion of contracts with private sector and strengthening public provisions and that neither of these disregard the need to strengthen public systems. Sustainability of contracting in arrangements, their effect on increasing coverage of EmOC services in rural areas and overlapping provisions for contracting in EmOC specialists are issues for future consideration.

Contracting in specialists for emergency obstetric care- does it work in rural India?

PubMed Central

2012-01-01

Background Contracting in private sector is promoted in developing countries facing human resources shortages as a challenge to reduce maternal mortality. This study explored provision, practice, performance, barriers to execution and views about contracting in specialists for emergency obstetric care (EmOC) in rural India. Methods Facility survey was conducted in all secondary and tertiary public health facilities (44) in three heterogeneous districts in Maharashtra state of India. Interviews (42) were conducted with programme managers and district and block level officials and with public and private EmOC specialists. Locations of private obstetricians in the study districts were identified and mapped. Results Two schemes, namely Janani Suraksha Yojana and Indian Public Health standards (IPHS) provided for contracting in EmOC specialists. The IPHS provision was chosen for use mainly due to greater sum for contracting in (US $ 30/service episode vs.300 US$/month). The positions of EmOC specialists were vacant in 83% of all facilities that hence had a potential for contracting in EmOC specialists. Private specialists were contracted in at 20% such facilities. The contracting in of specialists did not greatly increase EmOC service outputs at facilities, except in facilities with determined leadership. Contracting in specialists was useful for non emergency conditions, but not for obstetric emergencies. The contracts were more of a relational nature with poor monitoring structures. Inadequate infrastructure, longer distance to private specialists, insufficient financial provision for contracting in, and poor management capacities were barriers to effective implementation of contracting in. Dependency on the private sector was a concern among public partners while the private partners viewed contracting in as an opportunity to gain experience and credibility. Conclusions Density and geographic distribution of private specialists are important influencing factors in determining feasibility and use of contracting in for EmOC. Local circumstances dictate balance between introduction or expansion of contracts with private sector and strengthening public provisions and that neither of these disregard the need to strengthen public systems. Sustainability of contracting in arrangements, their effect on increasing coverage of EmOC services in rural areas and overlapping provisions for contracting in EmOC specialists are issues for future consideration. PMID:23276148

Transient lattice contraction in the solid to plasma transition of x-ray heated xenon clusters

NASA Astrophysics Data System (ADS)

Bostedt, C.; Ferguson, K.; Gorkhover, T.; Bucksbaum, P. H.; Boutet, S.; Koglin, J. E.; Lutman, A.; Marinelli, A.; Turner, J.; Bucher, M.; Ho, P.; Knight, C.; Young, L.; Fukuzawa, H.; Kumagai, Y.; Ueda, K.; Nagaya, K.; Messerschmidt, M.; Williams, G.

2016-05-01

Any sample in the focus of intense x-ray pulses will be transformed into a nanoplasma within femtoseconds. We have employed the novel two-color two-pulse mode available at the Linac Coherent Light Source free-electron laser to investigate the structural dynamics in nanoparticles upon x-ray exposure. We find that the nanoparticle transiently contracts within the first 80 fs following x-ray irradiation before ultimately disintegrating in a rapid hydrodynamic expansion. The contraction can be attributed to the massive x-ray induced electronic excitation that induces a collective change in the bond character of the nanoparticles. Alternative explanations for the contraction include a compression wave stemming from a rapid surface explosion of the nanoparticle. Computer simulations under way can elucidate the dominant contraction mechanism and yield further insight into the complex x-ray induced dynamics in nanoscale samples. This work is funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences, under Contract No. DE-AC02-06CH11357.

Interagency Report: Astrogeology 58, television cartography

USGS Publications Warehouse

Batson, Raymond M.

1973-01-01

The purpose of this paper is to illustrate the processing of digital television pictures into base maps. In this context, a base map is defined as a pictorial representation of planetary surface morphology accurately reproduced on standard map projections. Topographic contour lines, albedo or geologic overprints may be super imposed on these base maps. The compilation of geodetic map controls, the techniques of mosaic compilation, computer processing and airbrush enhancement, and the compilation of con tour lines are discussed elsewhere by the originators of these techniques. A bibliography of applicable literature is included for readers interested in more detailed discussions.

The Aqueous Alteration of CR Chondrites: Experiments and Geochemical Modeling

NASA Technical Reports Server (NTRS)

Perronnet, M.; Berger, G.; Zolensky, M. E.; Toplis, M. J.; Kolb, V. M.; Bajagic, M.

2007-01-01

CR carbonaceous chondrites are of major interest since they contain some of the most primitive organic matter known. However, aqueous alteration has more or less overprinted their original features in a way that needs to be assessed. This study was initiated by comparing the mineralogy and modal abundances of the most altered CR1 chondrite, GRO 95577, to a less altered CR2. Calculated element distributions imply that GRO 95577 may result from aqueous alteration of Renazzo by an isochemical process on their parent asteroid, whose mineralogical composition was estimated ( Unaltered CR shown included table).

Modeling Chemical and Isotopic Variations in Lab Formed Hydrothermal Carbonates

NASA Technical Reports Server (NTRS)

Niles, P. B.; Leshin, L. A.; Golden, D. C.; Socki, R. A.; Guan, Y.; Ming, D. W.

2005-01-01

Chemical and mineralogical data (e.g. [1]) from Mars suggest that the history of liquid water on the planet was more sporadic in nature than long-lived. The non-equilibrium chemical and isotopic compositions of the carbonates preserved in the martian meteorite ALH84001 are direct evidence of ancient secondary minerals that have not undergone significant diagenesis or stabilization processes typical of long-lived aqueous systems on Earth. Thus secondary minerals and sediments on Mars may primarily record the characteristics of the aqueous environment in which they formed without being significantly overprinted by subsequent diagenetic processes during burial.

Structural analysis and implicit 3D modelling of high-grade host rocks to the Venetia kimberlite diatremes, Central Zone, Limpopo Belt, South Africa

NASA Astrophysics Data System (ADS)

Basson, I. J.; Creus, P. K.; Anthonissen, C. J.; Stoch, B.; Ekkerd, J.

2016-05-01

The Beit Bridge Complex of the Central Zone (CZ) of the Limpopo Belt hosts the 519 ± 6 Ma Venetia kimberlite diatremes. Deformed shelf- or platform-type supracrustal sequences include the Mount Dowe, Malala Drift and Gumbu Groups, comprising quartzofeldspathic units, biotite-bearing gneiss, quartzite, metapelite, metacalcsilicate and ortho- and para-amphibolite. Previous studies define tectonometamorphic events at 3.3-3.1 Ga, 2.7-2.5 Ga and 2.04 Ga. Detailed structural mapping over 10 years highlights four deformation events at Venetia. Rules-based implicit 3D modelling in Leapfrog Geo™ provides an unprecedented insight into CZ ductile deformation and sheath folding. D1 juxtaposed gneisses against metasediments. D2 produced a pervasive axial planar foliation (S2) to isoclinal F2 folds. Sheared lithological contacts and S2 were refolded into regional, open, predominantly southward-verging, E-W trending F3 folds. Intrusion of a hornblendite protolith occurred at high angles to incipient S2. Constrictional-prolate D4 shows moderately NE-plunging azimuths defined by elongated hornblendite lenses, andalusite crystals in metapelite, crenulations in fuchsitic quartzite and sheath folding. D4 overlaps with a: 1) 2.03-2.01 Ga regional M3 metamorphic overprint; b) transpressional deformation at 2.2-1.9 Ga and c) 2.03 Ga transpressional, dextral shearing and thrusting around the CZ and d) formation of the Avoca, Bellavue and Baklykraal sheath folds and parallel lineations.

Soil heterogeneity in Mojave Desert shrublands: Biotic and abiotic processes

NASA Astrophysics Data System (ADS)

Caldwell, Todd G.; Young, Michael H.; McDonald, Eric V.; Zhu, Jianting

2012-09-01

Geological and ecological processes play critical roles in the evolution of desert piedmonts. Feedback between fast cyclic biotic and slow cumulative pedogenic processes on arid alluvial fan systems results in a heterogeneous landscape of interspace and canopy microsites. Defining the spatial extent between these processes will allow a better connection to ecosystem service and climate change. We use a soil chronosequence in the Mojave Desert and high spatial resolution infiltrometer measurements along transects radiating from canopies of perennial shrubs to assess the extent of biotic and abiotic processes and the heterogeneity of soil properties in arid shrublands. Results showed higher saturated conductivity under vegetation regardless of surface age, but it was more conspicuous on older, developed soils. At proximal locations to the shrub, bulk density, soil structure grade, silt, and clay content significantly increased radially from the canopy, while sand and organic material decreased. Soil properties at distal locations 2-5 times the canopy radius had no significant spatial correlation. The extent of the biotic influence of the shrub was 1.34 ± 0.32 times the canopy radius. Hydraulic properties were weakly correlated in space, but 75% of the variance could be attributed to sand content, soil structure grade, mean-particle diameter, and soil organic material, none of which are exclusively biotic or abiotic. The fast cyclic biotic processes occurring under vegetation are clearly overprinted on slow cumulative abiotic processes, resulting in the deterministic variability observed at the plant scale.

Extraordinary phase separation and segregation in vent fluids from the southern East Pacific Rise

USGS Publications Warehouse

Von Damm, Karen L.; Lilley, M.D.; Shanks, Wayne C.; Brockington, M.; Bray, A.M.; O'Grady, K. M.; Olson, E.; Graham, A.; Proskurowski, G.

2003-01-01

The discovery of Brandon vent on the southern East Pacific Rise is providing new insights into the controls on midocean ridge hydrothermal vent fluid chemistry. The physical conditions at the time ofsampling (287 bar and 405??C) place the Brandon fluids very close to the critical point of seawater (298 bar and 407??C). This permits in situ study of the effects of near criticalphenomena, which are interpreted to be the primary cause of enhanced transition metal transport in these fluids. Of the five orifices on Brandon sampled, three were venting fluids with less than seawater chlorinity, and two were venting fluids with greater than seawater chlorinity. The liquid phase orifices contain 1.6-1.9 times the chloride content of the vapors. Most other elements, excluding the gases, have this same ratio demonstrating the conservative nature of phase separation and the lack of subsequent water-rock interaction. The vapor and liquid phases vent at the same time from orifices within meters of each other on the Brandon structure. Variations in fluid compositions occur on a time scale of minutes. Our interpretation is that phase separation and segregation must be occurring 'real time' within the sulfide structure itself. Fluids from Brandon therefore provide an unique opportunity to understand in situ phase separation without the overprinting of continued water-rock interaction with the oceanic crust, as well as critical phenomena. ?? 2002 Elsevier Science B.V. All rights reserved.

40 CFR 35.6015 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

..., repair, remodeling, improvement, or extension of buildings, structures or other property. Contract. A... 300. Operable unit. A discrete action, as described in the Cooperative Agreement or Superfund State...). Real property. Land, including land improvements, structures, and appurtenances thereto, excluding...

40 CFR 35.6015 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-07-01

..., repair, remodeling, improvement, or extension of buildings, structures or other property. Contract. A... 300. Operable unit. A discrete action, as described in the Cooperative Agreement or Superfund State...). Real property. Land, including land improvements, structures, and appurtenances thereto, excluding...

Consolidation of medical groups into physician practice management organizations.

PubMed

Robinson, J C

1998-01-14

Medical groups are growing and merging to improve efficiency and bargaining leverage in the competitive managed care environment. An increasing number are affiliating with physician practice management (PPM) firms that offer capital financing, expertise in utilization management, and global capitation contracts with health insurance entities. These physician organizations provide an alternative to affiliation with a hospital system and to individual physician contracting with health plans. To describe the growth, structure, and strategy of PPM organizations that coordinate medical groups in multiple markets and contract with health maintenance organizations (HMOs). Case studies, including interviews with administrative and clinical leaders, review of company documents, and analysis of documents from investment bankers, the Securities and Exchange Commission, and industry observers. Medical groups and independent practice associations (IPAs) in California and New Jersey affiliated with MedPartners, FPA Medical Management, and UniMed. Growth in number of primary care and specialty care physicians employed by and contracting with affiliated medical groups; growth in patient enrollment from commercial, Medicare, and Medicaid HMOs; growth in capitation and noncapitation revenues; structure and governance of affiliated management service organizations and professional corporations; and contracting strategies with HMOs. Between 1994 and 1996, medical groups and IPAs affiliated with 3 PPMs grew from 3787 to 25763 physicians; 65% of employed physicians provide primary care, while the majority of contracting physicians provide specialty care. Patient enrollment in HMOs grew from 285503 to 3028881. Annual capitation revenues grew from $190 million to $2.1 billion. Medical groups affiliated with PPMs are capitated for most professional, hospital, and ancillary clinical services and are increasingly delegated responsibility by HMOs for utilization management and quality assurance. Physician practice management organizations and their affiliated medical groups face the challenge of continuing rapid growth, sustaining stock values, and improving practice efficiencies while maintaining the loyalty of physicians and patients.

Deal-Making 2.0: A New Experiential Simulation in Contract Negotiation and Drafting for Business Students in the Global and Digital Age

ERIC Educational Resources Information Center

Klaw, Bruce W.

2016-01-01

This article presents a new contract negotiation and drafting exercise designed for undergraduate and graduate business students in a business law or legal environment of business survey course. Structured as an asset purchase and sale agreement involving a small business with intangible social media and intellectual property assets in a…

Contracts and Management Services FY 1996 Site Support Program Plan: WBS 6.10.14. Revision 1

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

Knoll, J.M. Jr.

1995-09-01

This is the Contracts and Management Services site support program plan for the US DOE Hanford site. The topics addressed in the program plan include a mission statement, program objectives, planning assumptions, program constraints, work breakdown structure, milestone list, milestone description sheets, and activity detail including cost accounting narrative summary, approved funding budget, and activity detailed description.

Strain localization in a fossilized subduction channel: Insights from the Cycladic Blueschist Unit (Syros, Greece)

NASA Astrophysics Data System (ADS)

Laurent, Valentin; Jolivet, Laurent; Roche, Vincent; Augier, Romain; Scaillet, Stéphane; Cardello, Giovanni Luca

2016-03-01

Syros Island is worldwide known for its preservation of HP-LT parageneses in the Cycladic Blueschist Unit (CBU) providing one of the best case-studies to understand the tectonometamorphic evolution of a subduction channel. Conflicting structural interpretations have been proposed to explain the geological architecture of Syros, in part reflecting a lack of consensus about the tectonic structure of the CBU. In this study, the geological and tectonometamorphic maps of Syros have been entirely redrawn in order to decipher the structure of a fossilized subduction channel. Based on structural and petrological observations, the CBU has been subdivided into three subunits separated by major ductile shear zones. New observations of the Vari Unit confirm that it rests on top of the CBU through a detachment or exhumation fault. While retrograde top-to-the E/NE shearing overprinting prograde deformation is widespread across the island, the prograde deformation has been only locally preserved within the less retrograded units. We show that after the prograde top-to-the S/SW shearing deformation, the CBU was exhumed by an overall top-to-the E/NE shearing from the depth of the eclogite-facies all the way to the depth of the greenschist-facies and finally, to the brittle crust. The exhumation process encompassed the syn-orogenic stage (contemporaneous of subduction, within the subduction channel - Eocene) to the post-orogenic stage (contemporaneous with the formation of the Aegean Sea - Oligocene to Miocene). From syn-orogenic to post-orogenic exhumation, deformation progressively localized toward the base of the CBU, along large-scale ductile shear zones, allowing the preservation of earlier HP-LT structures and HP-LT metamorphic parageneses. Finally, this study brings new insights on the tectonometamorphic evolution of a subduction channel showing how strain localizes during the history of an accretionary complex, both during the prograde and retrograde history.

Structural interpretation of aeromagnetic data for the Wadi El Natrun area, northwestern desert, Egypt

NASA Astrophysics Data System (ADS)

Ibraheem, Ismael M.; Elawadi, Eslam A.; El-Qady, Gad M.

2018-03-01

The Wadi El Natrun area in Egypt is located west of the Nile Delta on both sides of the Cairo-Alexandria desert road, between 30°00‧ and 30°40‧N latitude, and 29°40‧ and 30°40‧E longitude. The name refers to the NW-SE trending depression located in the area and containing lakes that produce natron salt. In spite of the area is promising for oil and gas exploration as well as agricultural projects, Geophysical studies carried out in the area is limited to the regional seismic surveys accomplished by oil companies. This study presents the interpretation of the airborne magnetic data to map the structure architecture and depth to the basement of the study area. This interpretation was facilitated by applying different data enhancement and processing techniques. These techniques included filters (regional-residual separation), derivatives and depth estimation using spectral analysis and Euler deconvolution. The results were refined using 2-D forward modeling along three profiles. Based on the depth estimation techniques, the estimated depth to the basement surface, ranges from 2.25 km to 5.43 km while results of the two-dimensional forward modeling show that the depth of the basement surface ranges from 2.2 km to 4.8 km. The dominant tectonic trends in the study area at deep levels are NW (Suez Trend), NNW, NE, and ENE (Syrian Arc System trend). The older ENE trend, which dominates the northwestern desert is overprinted in the study area by relatively recent NW and NE trends, whereas the tectonic trends at shallow levels are NW, ENE, NNE (Aqaba Trend), and NE. The predominant structure trend for both deep and shallow structures is the NW trend. The results of this study can be used to better understand deep-seated basement structures and to support decisions with regard to the development of agriculture, industrial areas, as well as oil and gas exploration in northern Egypt.

48 CFR 1815.404-471 - NASA structured approach for profit or fee objective.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 48 Federal Acquisition Regulations System 6 2011-10-01 2011-10-01 false NASA structured approach for profit or fee objective. 1815.404-471 Section 1815.404-471 Federal Acquisition Regulations System... NEGOTIATION Contract Pricing 1815.404-471 NASA structured approach for profit or fee objective. ...

48 CFR 1815.404-471 - NASA structured approach for profit or fee objective.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 48 Federal Acquisition Regulations System 6 2013-10-01 2013-10-01 false NASA structured approach for profit or fee objective. 1815.404-471 Section 1815.404-471 Federal Acquisition Regulations System... NEGOTIATION Contract Pricing 1815.404-471 NASA structured approach for profit or fee objective. ...

32 CFR 643.115 - Contractors-Permission to erect structures.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 32 National Defense 4 2010-07-01 2010-07-01 true Contractors-Permission to erect structures. 643... (CONTINUED) REAL PROPERTY REAL ESTATE Additional Authority of Commanders § 643.115 Contractors—Permission to... the structure is to be used for any purpose other than the fulfillment of the contract, application...

Research of TREETOPS Structural Dynamics Controls Simulation Upgrade

NASA Technical Reports Server (NTRS)

Yates, Rose M.

1996-01-01

Under the provisions of contract number NAS8-40194, which was entitled 'TREETOPS Structural Dynamics and Controls Simulation System Upgrade', Oakwood College contracted to produce an upgrade to the existing TREETOPS suite of analysis tools. This suite includes the main simulation program, TREETOPS, two interactive preprocessors, TREESET and TREEFLX, an interactive post processor, TREEPLOT, and an adjunct program, TREESEL. A 'Software Design Document', which provides descriptions of the argument lists and internal variables for each subroutine in the TREETOPS suite, was established. Additionally, installation guides for both DOS and UNIX platforms were developed. Finally, updated User's Manuals, as well as a Theory Manual, were generated.

Patterns of residual stresses due to welding

NASA Technical Reports Server (NTRS)

Botros, B. M.

1983-01-01

Residual stresses caused by welding result from the nonuniform rate of cooling and the restrained thermal contraction or non-uniform plastic deformation. From the zone of extremely high temperature at the weld, heat flows into both the adjoining cool body and the surrounding atmosphere. The weld metal solidifies under very rapid cooling. The plasticity of the hot metal allows adjustment initially, but as the structure cools the rigidity of the surrounding cold metal inhibits further contraction. The zone is compressed and the weld is put under tensile stresses of high magnitude. The danger of cracking in these structural elements is great. Change in specific volume is caused by the change in temperature.

[Dynamic of marriage structure in three cities of Ukraine from 1960 to 1992].

PubMed

Timchenko, O I; Omel'chenko, E M; Nikula, E T

2000-04-01

Marriage structure was studied in the city of Kiev and in two cities of the Sumy oblast, Shostka and Trostyanets. Ethnic affiliations and birthplaces of persons contracting marriage were analyzed as the main characteristics of population genetic diversity. The ethnic composition of persons contracting marriage and the proportions of mono- and interethnic marriages remained almost unchanged during one generation. The majority of the persons contracting marriage were Ukrainians (66-91%); among other ethnic groups, only Russians considerably contributed to ethnic diversity (up to 26%). During the period studied, coefficients of marital migration substantially decreased in Kiev (from 0.66-0.82 to 0.34) and Shostka (from 0.72 to 0.52) and changed only insignificantly in Trostyanets. Outbreeding was estimated based on the migration parameters, exogamy level, and marital migration distances. The outbreeding level in the Shostka population (100,000 people) was comparable with that for the considerably larger Kiev population (two million people); however, it was significantly higher than that for the Trostyanets population, the size of which was close to the size of the Shostka population. It is supposed that "migration stress" may unfavorably affect the adaptive genetic structure of the Shostka population.

A numerical simulation of peristaltic motion in the ureter using fluid structure interactions.

PubMed

Vahidi, Bahman; Fatouraee, Nasser

2007-01-01

An axisymmetric model with fluid-structure interactions (FSI) is introduced and solved to perform ureter flow and stress analysis. The Navier-Stokes equations are solved for the fluid and a linear elastic model for ureter is used. The finite element equations for both the structure and the fluid were solved by the Newton-Raphson iterative method. Our results indicated that shear stresses were high around the throat of moving contracted wall. The pressure gradient magnitude along the ureter wall and the symmetry line had the maximum value around the throat of moving contracted wall which decreased as the peristalsis propagates toward the bladder. The flow rate at the ureter outlet at the end of the peristaltic motion was about 650 mm3/s. During propagation of the peristalsis toward the bladder, the inlet backward flow region was limited to the areas near symmetry line but the inner ureter backward flow regions extended to the whole ureter contraction part. The backward flow was vanished after 1.5 seconds of peristalsis propagation start up and after that time the urine flow was forward in the whole ureter length, so reflux is more probable to be present at the beginning of the wall peristaltic motion.

The policy implications of the cost structure of home health agencies.

PubMed

Mukamel, Dana B; Fortinsky, Richard H; White, Alan; Harrington, Charlene; White, Laura M; Ngo-Metzger, Quyen

2014-01-01

To examine the cost structure of home health agencies by estimating an empirical cost function for those that are Medicare-certified, ten years following the implementation of prospective payment. 2010 national Medicare cost report data for certified home health agencies were merged with case-mix information from the Outcome and Assessment Information Set (OASIS). We estimated a fully interacted (by tax status) hybrid cost function for 7,064 agencies and calculated marginal costs as percent of total costs for all variables. The home health industry is dominated by for-profit agencies, which tend to be newer than the non-profit agencies and to have higher average costs per patient but lower costs per visit. For-profit agencies tend to have smaller scale operations and different cost structures, and are less likely to be affiliated with chains. Our estimates suggest diseconomies of scale, zero marginal cost for contracting with therapy workers, and a positive marginal cost for contracting with nurses, when controlling for quality. Our findings suggest that efficiencies may be achieved by promoting non-profit, smaller agencies, with fewer contract nursing staff. This conclusion should be tested further in future studies that address some of the limitations of our study.

Strengthening district health service management and delivery through internal contracting: lessons from pilot projects in Cambodia.

PubMed

Khim, Keovathanak; Annear, Peter Leslie

2013-11-01

Following a decade of piloting different models of contracting, in mid-2009 the Cambodian Ministry of Health began to test a form of 'internal contracting' for health care delivery in selected health districts (including hospitals and health centers) contracted by the provincial health department as Special Operating Agencies (SOAs) and provided with greater management autonomy. This study assesses the internal contracting approach as a means for improving the management of district health services and strengthening service delivery. While the study may contribute to the emerging field now known as performance-based financing, the lessons deal more broadly with the impact of management reform and increased autonomy in contrast to traditional public sector line-management and budgeting. Carried out during 2011, the study was based on: (i) a review of the literature and of operational documents; (ii) primary data from semi-structured key informant interviews with 20 health officials in two provinces involved in four SOA pilot districts; and (iii) routine data from the 2011 SOA performance monitoring report. Five prerequisites were identified for effective contract management and improved service delivery: a clear understanding of roles and responsibilities by the contracting parties; implementation of clear rules and procedures; effective management of performance; effective monitoring of the contract; and adequate and timely provision of resources. Both the level and allocation of incentives and management bottlenecks at various levels continue to impede implementation. We conclude that, in contracted arrangements like these, the clear separation of contracting functions (purchasing, commissioning, monitoring and regulating), management autonomy where responsibilities are genuinely devolved and accepted, and the provision of resources adequate to meet contract demands are necessary conditions for success. Copyright © 2013 Elsevier Ltd. All rights reserved.

Perceived barriers to utilizing maternal and neonatal health services in contracted-out versus government-managed health facilities in the rural districts of Pakistan.

PubMed

Riaz, Atif; Zaidi, Shehla; Khowaja, Asif Raza

2015-03-06

A number of developing countries have contracted out public health facilities to the Non-Government Organizations (NGOs) in order to improve service utilization. However, there is a paucity of in-depth qualitative information on barriers to access services as a result of contracting from service users' perspective. The objective of this study was to explore perceived barriers to utilizing Maternal and Neonatal Health (MNH) services, in health facilities contracted out by government to NGO for service provision versus in those which are managed by government (non-contracted). A community-based qualitative exploratory study was conducted between April to September 2012 at two contracted-out and four matched non-contracted primary healthcare facilities in Thatta and Chitral, rural districts of Pakistan. Using semi-structured guide, the data were collected through thirty-six Focus Group Discussions (FGDs) conducted with mothers and their spouses in the catchment areas of selected facilities. Thematic analysis was performed using NVivo version 10.0 in which themes and sub-themes emerged. Key barriers reported in contracted sites included physical distance, user charges and familial influences. Whereas, poor functionality of health centres was the main barrier for non-contracted sites with other issues being comparatively less salient. Decision-making patterns for participants of both catchments were largely similar. Spouses and mother-in-laws particularly influenced the decision to utilize health facilities. Contracting out of health facility reduces supply side barriers to MNH services for the community served but distance, user charges and low awareness remain significant barriers. Contracting needs to be accompanied by measures for transportation in remote settings, oversight on user fee charges by contractor, and strong community-based behavior change strategies. © 2015 by Kerman University of Medical Sciences.

Perceived barriers to utilizing maternal and neonatal health services in contracted-out versus government-managed health facilities in the rural districts of Pakistan

PubMed Central

Riaz, Atif; Zaidi, Shehla; Khowaja, Asif Raza

2015-01-01

Background: A number of developing countries have contracted out public health facilities to the Non-Government Organizations (NGOs) in order to improve service utilization. However, there is a paucity of in-depth qualitative information on barriers to access services as a result of contracting from service users’ perspective. The objective of this study was to explore perceived barriers to utilizing Maternal and Neonatal Health (MNH) services, in health facilities contracted out by government to NGO for service provision versus in those which are managed by government (non-contracted). Methods: A community-based qualitative exploratory study was conducted between April to September 2012 at two contracted-out and four matched non-contracted primary healthcare facilities in Thatta and Chitral, rural districts of Pakistan. Using semi-structured guide, the data were collected through thirty-six Focus Group Discussions (FGDs) conducted with mothers and their spouses in the catchment areas of selected facilities. Thematic analysis was performed using NVivo version 10.0 in which themes and sub-themes emerged. Results: Key barriers reported in contracted sites included physical distance, user charges and familial influences. Whereas, poor functionality of health centres was the main barrier for non-contracted sites with other issues being comparatively less salient. Decision-making patterns for participants of both catchments were largely similar. Spouses and mother-in-laws particularly influenced the decision to utilize health facilities. Conclusion: Contracting out of health facility reduces supply side barriers to MNH services for the community served but distance, user charges and low awareness remain significant barriers. Contracting needs to be accompanied by measures for transportation in remote settings, oversight on user fee charges by contractor, and strong community-based behavior change strategies. PMID:25905478

Decentralized adaptive control designs and microstrip antennas for smart structures

NASA Astrophysics Data System (ADS)

Khorrami, Farshad; Jain, Sandeep; Das, Nirod K.

1996-05-01

Smart structures lend themselves naturally to a decentralized control design framework, especially with adaptation mechanisms. The main reason being that it is highly undesirable to connect all the sensors and actuators in a large structure to a central processor. It is rather desirable to have local decision-making at each smart patch. Furthermore, this local controllers should be easily `expandable' to `contractible.' This corresponds to the fact that addition/deletion of several smart patches should not require a total redesign of the control system. The decentralized control strategies advocated in this paper are of expandable/contractible type. On another front, we are considering utilization of micro-strip antennas for power transfer to and from smart structures. We have made preliminary contributions in this direction and further developments are underway. These approaches are being pursued for active vibration damping and noise cancellation via piezoelectric ceramics although the methodology is general enough to be applicable to other type of active structures.

Active noise control using noise source having adaptive resonant frequency tuning through variable ring loading

NASA Technical Reports Server (NTRS)

Rajiyah, Harindra (Inventor); Pla, Frederic G. (Inventor); Hedeen, Robert A. (Inventor); Renshaw, Anthony A. (Inventor)

1995-01-01

A noise source for an aircraft engine active noise cancellation system in which the resonant frequency of noise radiating structure is tuned to permit noise cancellation over a wide range of frequencies. The resonant frequency of the noise radiating structure is tuned by a plurality of drivers arranged to contact the noise radiating structure. Excitation of the drivers causes expansion or contraction of the drivers, thereby varying the edge loading applied to the noise radiating structure. The drivers are actuated by a controller which receives input of a feedback signal proportional to displacement of the noise radiating element and a signal corresponding to the blade passage frequency of the engine's fan. In response, the controller determines a control signal which is sent to the drivers, causing them to expand or contract. The noise radiating structure may be either the outer shroud of the engine or a ring mounted flush with an inner wall of the shroud or disposed in the interior of the shroud.

Complex high-strain deformation in the Usagaran Orogen, Tanzania: structural setting of Palaeoproterozoic eclogites

NASA Astrophysics Data System (ADS)

Reddy, S. M.; Collins, A. S.; Mruma, A.

2003-11-01

The Palaeoproterozoic Usagaran Orogen of Tanzania contains the Earth's oldest reported examples of subduction-related eclogite facies rocks. Detailed field mapping of gneisses exposed in the high-grade, eclogite-bearing part of the orogen (the Isimani Suite) indicates a complex deformation and thermal history. Deformation in the Isimani Suite can be broadly subdivided into five events. The first of these (D 1), associated with formation of eclogite facies metamorphism, is strongly overprinted by a pervasive deformation (D 2) at amphibolite facies conditions, which resulted in the accumulation of high strains throughout all of the exposed Isimani rocks. The geometry of foliations and lineations developed during D 2 deformation are variable and have different shear directions that enable five D 2 domains to be identified. Analysis of these domains indicates a geometrical and kinematic pattern that is interpreted to have formed by strain and kinematic partitioning during sinistral transpression. U-Pb SHRIMP zircon ages from a post-D 2 granite and previously published geochronological data from the Usagaran eclogites indicate this deformation took place between 2000 ± 1 Ma and 1877 ± 7 Ma (at 1σ error). Subsequent greenschist facies deformation, localised as shear zones on boundaries separating D 2 domains, have both contractional and extensional geometries that indicate post-1877 Ma reactivation of the Isimani Suite. This reactivation may have taken place during Palaeoproterozoic exhumation of the Usagaran Orogen or may be the result of deformation associated with the Neoproterozoic East African Orogen. U-Th-Pb SHRIMP zircon ages from an Isimani gneiss sample and xenocrysts in a "post-tectonic" granite yield ˜2.7 Ga ages and are similar to published Nd model ages from both the Tanzanian Craton and gneiss exposed east of the Usagaran belt in the East African Orogen. These age data indicate that the Isimani Suite of the Usagaran Orogen reflects reworking of Archaean continental crust. The extensive distribution of ˜2.7 Ga crust in both the footwall and hangingwall of the Usagaran Orogen can only be explained by the collision of two continents if the continents fortuitously had the same protolith ages. We propose that a more likely scenario is that the protoliths of the mafic eclogites were erupted in a marginal basin setting as either oceanic crust, or as limited extrusions along the rifted margin of the Tanzanian Craton. The Usagaran Orogen may therefore reflect the mid-Palaeoproterozoic reassembly of a continental ribbon partially or completely rifted off the craton and separated from it by a marginal basin.

Structural hysteresis in dragline spider silks induced by supercontraction: an X-ray fiber micro-diffraction study

DOE PAGES

Sampath, Sujatha; Yarger, Jeffery L.

2014-11-27

Interaction with water causes shrinkage and significant changes in the structure of spider dragline silks, which has been referred to as supercontraction in the literature. Preferred orientation or alignment of protein chains with respect to the fiber axis is extensively changed during this supercontraction process. Synchrotron X-ray micro-fiber diffraction experiments have been performed on Nephila clavipes and Argiope aurantia major and minor ampullate dragline spider fibers in the native dry, contracted (by immersion in water) and restretched (from contracted) states. Changes in the orientation of β-sheet nanocrystallites and the oriented component of the amorphous network have been determined from wide-anglemore » X-ray diffraction patterns. While both the crystalline and amorphous components lose preferred orientation on wetting with water, the nano-crystallites regain their orientation on wet-restretching, whereas the oriented amorphous components only partially regain their orientation. Dragline major ampullate silks in both the species contract more than their minor ampullate silks.« less

The private management of public hospitals.

PubMed Central

Rundall, T G; Lambert, W K

1984-01-01

Since the public sector traditionally has provided the public goods viewed as unprofitable by the private sector, the growing trend to manage public hospitals under outside private contract raises some fundamental issues of concern. It is hypothesized here that the system maintenance and output goals of privately managed public hospitals become increasingly similar to those of investor-owned hospitals. The thesis is empirically tested using documented effects of private contract management on the operative goals of short-term, general hospitals owned by local governmental bodies. Traditionally managed public hospitals matched with the study hospitals on important characteristics serve as the control group. Costs do appear to be reduced under private contract management, but the service structure becomes somewhat altered. It is the task of public health policymakers to reconcile the cost-control and efficiency mechanisms brought about by private management with the community's right of access to comprehensive medical care. Carefully structured regionalization plans--a possible means of providing both--will require the stimulation of more government involvement during an era of cutbacks. PMID:6490379

Thermal Expansion Coefficient of Cold-Pressed Silicon Carbide

NASA Astrophysics Data System (ADS)

Olivieri, E.; Pasca, E.; Ventura, G.; Barucci, M.; Risegari, L.

2004-07-01

The measurement of the thermal linear expansion coefficient of a cold sintered SiC has been carried out in the 4.2 - 293 K temperature range. The properties of silicon carbide are specially suitable to realise high quality mirrors and complete optomechanical structures for space astronomy. The thermal contraction of the material used for the realization of the mirror is, of course, of primary interest. We present here both a plot and smoothed data of SiC thermal contraction coefficient. Details of the dilatometric interferometer used to carry out the measurements are also reported together with a control test of the measuring bench on a material (brass) of known thermal contraction.

Molecular mechanisms underlying airway smooth muscle contraction and proliferation: implications for asthma.

PubMed

Pelaia, Girolamo; Renda, Teresa; Gallelli, Luca; Vatrella, Alessandro; Busceti, Maria Teresa; Agati, Sergio; Caputi, Mario; Cazzola, Mario; Maselli, Rosario; Marsico, Serafino A

2008-08-01

Airway smooth muscle (ASM) plays a key role in bronchomotor tone, as well as in structural remodeling of the bronchial wall. Therefore, ASM contraction and proliferation significantly participate in the development and progression of asthma. Many contractile agonists also behave as mitogenic stimuli, thus contributing to frame a hyperresponsive and hyperplastic ASM phenotype. In this review, the molecular mechanisms and signaling pathways involved in excitation-contraction coupling and ASM cell growth will be outlined. Indeed, the recent advances in understanding the basic aspects of ASM biology are disclosing important cellular targets, currently explored for the implementation of new, more effective anti-asthma therapies.

Paint and Shoot

NASA Technical Reports Server (NTRS)

1999-01-01

Through an initial SBIR contract with Langley Research Center, Stress Photonics, Inc. was able to successfully market their thermal strain measurement device, known as the Delta Therm 1000. The company was able to further its research on structural integrity analysis by signing another contract with Langley, this time a STTR contract, to develop its polariscope stress technology. Their commercial polariscope, the GFP 1000, involves a single rotating optical element and a digital camera for full-field image acquisition. The digital camera allows automated data to be acquired quickly and efficiently. Software analysis presents the data in an easy to interpret image format, depicting the magnitude of the shear strains and the directions of the principal strains.

Constraints Imposed by Rift Inheritance on the Compressional Reactivation of a Hyperextended Margin: Mapping Rift Domains in the North Iberian Margin and in the Cantabrian Mountains

NASA Astrophysics Data System (ADS)

Cadenas, P.; Fernández-Viejo, G.; Pulgar, J. A.; Tugend, J.; Manatschal, G.; Minshull, T. A.

2018-03-01

The Alpine Pyrenean-Cantabrian orogen developed along the plate boundary between Iberia and Europe, involving the inversion of Mesozoic hyperextended basins along the southern Biscay margin. Thus, this margin represents a natural laboratory to analyze the control of structural rift inheritance on the compressional reactivation of a continental margin. With the aim to identify former rift domains and investigate their role during the subsequent compression, we performed a structural analysis of the central and western North Iberian margin, based on the interpretation of seismic reflection profiles and local constraints from drill-hole data. Seismic interpretations and published seismic velocity models enabled the development of crustal thickness maps that helped to constrain further the offshore and onshore segmentation. Based on all these constraints, we present a rift domain map across the central and western North Iberian margin, as far as the adjacent western Cantabrian Mountains. Furthermore, we provide a first-order description of the margin segmentation resulting from its polyphase tectonic evolution. The most striking result is the presence of a hyperthinned domain (e.g., Asturian Basin) along the central continental platform that is bounded to the north by the Le Danois High, interpreted as a rift-related continental block separating two distinctive hyperextended domains. From the analysis of the rift domain map and the distribution of reactivation structures, we conclude that the landward limit of the necking domain and the hyperextended domains, respectively, guide and localize the compressional overprint. The Le Danois block acted as a local buttress, conditioning the inversion of the Asturian Basin.

The Cenozoic fold-and-thrust belt of Eastern Sardinia: Evidences from the integration of field data with numerically balanced geological cross section

NASA Astrophysics Data System (ADS)

Arragoni, S.; Maggi, M.; Cianfarra, P.; Salvini, F.

2016-06-01

Newly collected structural data in Eastern Sardinia (Italy) integrated with numerical techniques led to the reconstruction of a 2-D admissible and balanced model revealing the presence of a widespread Cenozoic fold-and-thrust belt. The model was achieved with the FORC software, obtaining a 3-D (2-D + time) numerical reconstruction of the continuous evolution of the structure through time. The Mesozoic carbonate units of Eastern Sardinia and their basement present a fold-and-thrust tectonic setting, with a westward direction of tectonic transport (referred to the present-day coordinates). The tectonic style of the upper levels is thin skinned, with flat sectors prevailing over ramps and younger-on-older thrusts. Three regional tectonic units are present, bounded by two regional thrusts. Strike-slip faults overprint the fold-and-thrust belt and developed during the Sardinia-Corsica Block rotation along the strike of the preexisting fault ramps, not affecting the numerical section balancing. This fold-and-thrust belt represents the southward prosecution of the Alpine Corsica collisional chain and the missing link between the Alpine Chain and the Calabria-Peloritani Block. Relative ages relate its evolution to the meso-Alpine event (Eocene-Oligocene times), prior to the opening of the Tyrrhenian Sea (Tortonian). Results fill a gap of information about the geodynamic evolution of the European margin in Central Mediterranean, between Corsica and the Calabria-Peloritani Block, and imply the presence of remnants of this double-verging belt, missing in the Southern Tyrrhenian basin, within the Southern Apennine chain. The used methodology proved effective for constraining balanced cross sections also for areas lacking exposures of the large-scale structures, as the case of Eastern Sardinia.

Characterization of Navajo Sandstone concretions: Mars comparison and criteria for distinguishing diagenetic origins

NASA Astrophysics Data System (ADS)

Potter, Sally L.; Chan, Marjorie A.; Petersen, Erich U.; Dyar, M. Darby; Sklute, Elizabeth

2011-01-01

The eolian Jurassic Navajo Sandstone spheroidal hydrous ferric oxide (HFO) concretions are divided into two size classes: macro-concretions of > 5 mm diameter and micro-concretions of < 5 mm diameter. Three internal structural end-members of macro-concretions are described as rind, layered, and solid. Two end-members of micro-concretions are rind and solid. Chemical and mineralogical gradients (μm- to mm-scale) are identified with QEMSCAN (Quantitative Elemental Mineralogy using a SCANning electron microscope) and visible to near infrared (VNIR) reflectance spectroscopy. Three HFO phases are identified using VNIR reflectance spectroscopy. An amorphous HFO phase is typically located in the rinds. Goethite is present along interior edges of rinds and throughout the interiors of layered and solid concretions. Hematite is present in the centers of rind concretions. A synthesis of petrographic, mineralogical and chemical analyses suggests that concretions grow pervasively (as opposed to radially expanding). Our model proposes that concretions precipitate initially as an amorphous HFO that sets the radius and retains some original porosity. Subsequent precipitation fills remaining pore space with younger mineral phases. Inward digitate cement crystal growth corroborates concretion growth from a set radius toward the centers. Internal structure is modified during late stage precipitation that diffuses reactants through semi-permeable rinds and overprints the interiors with younger cements. Physical characterization of textures and minerals provides diagnostic criteria for understanding how similar concretions ("blueberries") form in Meridiani Planum, Mars. The analogous Navajo Sandstone concretions show similar characteristics of in situ self-organized spacing, spheroidal geometries, internal structures, conjoined forms, and precursor HFO phases that dehydrate to goethite or hematite. These characteristics indicate a common origin via groundwater diagenesis.

Evolution and Structural Organization of the C Proteins of Paramyxovirinae

PubMed Central

Karlin, David G.

2014-01-01

The phosphoprotein (P) gene of most Paramyxovirinae encodes several proteins in overlapping frames: P and V, which share a common N-terminus (PNT), and C, which overlaps PNT. Overlapping genes are of particular interest because they encode proteins originated de novo, some of which have unknown structural folds, challenging the notion that nature utilizes only a limited, well-mapped area of fold space. The C proteins cluster in three groups, comprising measles, Nipah, and Sendai virus. We predicted that all C proteins have a similar organization: a variable, disordered N-terminus and a conserved, α-helical C-terminus. We confirmed this predicted organization by biophysically characterizing recombinant C proteins from Tupaia paramyxovirus (measles group) and human parainfluenza virus 1 (Sendai group). We also found that the C of the measles and Nipah groups have statistically significant sequence similarity, indicating a common origin. Although the C of the Sendai group lack sequence similarity with them, we speculate that they also have a common origin, given their similar genomic location and structural organization. Since C is dispensable for viral replication, unlike PNT, we hypothesize that C may have originated de novo by overprinting PNT in the ancestor of Paramyxovirinae. Intriguingly, in measles virus and Nipah virus, PNT encodes STAT1-binding sites that overlap different regions of the C-terminus of C, indicating they have probably originated independently. This arrangement, in which the same genetic region encodes simultaneously a crucial functional motif (a STAT1-binding site) and a highly constrained region (the C-terminus of C), seems paradoxical, since it should severely reduce the ability of the virus to adapt. The fact that it originated twice suggests that it must be balanced by an evolutionary advantage, perhaps from reducing the size of the genetic region vulnerable to mutations. PMID:24587180

Geologic columns for the ICDP-USGS Eyreville B core, Chesapeake Bay impact structure: Impactites and crystalline rocks, 1766 to 1096 m depth

USGS Publications Warehouse

Horton, J. Wright; Gibson, R.L.; Reimold, W.U.; Wittmann, A.; Gohn, G.S.; Edwards, L.E.

2009-01-01

The International Continental Scientific Drilling Program (ICDP)-U.S. Geological Survey (USGS) Eyreville drill cores from the Chesapeake Bay impact structure provide one of the most complete geologic sections ever obtained from an impact structure. This paper presents a series of geologic columns and descriptive lithologic information for the lower impactite and crystalline-rock sections in the cores. The lowermost cored section (1766-1551 m depth) is a complex assemblage of mica schists that commonly contain graphite and fibrolitic sillimanite, intrusive granite pegmatites that grade into coarse granite, and local zones of mylonitic deformation. This basement-derived section is variably overprinted by brittle cataclastic fabrics and locally cut by dikes of polymict impact breccia, including several suevite dikes. An overlying succession of suevites and lithic impact breccias (1551-1397 m) includes a lower section dominated by polymict lithic impact breccia with blocks (up to 17 m) and boulders of cataclastic gneiss and an upper section (above 1474 m) of suevites and clast-rich impact melt rocks. The uppermost suevite is overlain by 26 m (1397-1371 m) of gravelly quartz sand that contains an amphibolite block and boulders of cataclasite and suevite. Above the sand, a 275-m-thick allochthonous granite slab (1371-1096 m) includes gneissic biotite granite, fine- and medium-to-coarse-grained biotite granites, and red altered granite near the base. The granite slab is overlain by more gravelly sand, and both are attributed to debris-avalanche and/or rockslide deposition that slightly preceded or accompanied seawater-resurge into the collapsing transient crater. ?? 2009 The Geological Society of America.

Formation of dome and basin structures: Results from scaled experiments using non-linear rock analogues

NASA Astrophysics Data System (ADS)

Zulauf, J.; Zulauf, G.; Zanella, F.

2016-09-01

Dome and basin folds are structures with circular or slightly elongate outcrop patterns, which can form during single- and polyphase deformation in various tectonic settings. We used power-law viscous rock analogues to simulate single-phase dome-and-basin folding of rocks undergoing dislocation creep. The viscosity ratio between a single competent layer and incompetent matrix was 5, and the stress exponent of both materials was 7. The samples underwent layer-parallel shortening under bulk pure constriction. Increasing initial layer thickness resulted in a decrease in the number of domes and basins and an increase in amplitude, A, arc-length, L, wavelength, λ, and layer thickness, Hf. Samples deformed incrementally show progressive development of domes and basins until a strain of eY=Z = -30% is attained. During the dome-and-basin formation the layer thickened permanently, while A, L, and λ increased. A dominant wavelength was not attained. The normalized amplitude (A/λ) increased almost linearly reaching a maximum of 0.12 at eY=Z = -30%. During the last increment of shortening (eY=Z = -30 to -40%) the domes and basins did not further grow, but were overprinted by a second generation of non-cylindrical folds. Most of the geometrical parameters of the previously formed domes and basins behaved stable or decreased during this phase. The normalized arc-length (L/Hf) of domes and basins is significantly higher than that of 2D cylindrical folds. For this reason, the normalized arc length can probably be used to identify domes and basins in the field, even if these structures are not fully exposed in 3D.

Visualization of synchronization of the uterine contraction signals: running cross-correlation and wavelet running cross-correlation methods.

PubMed

Oczeretko, Edward; Swiatecka, Jolanta; Kitlas, Agnieszka; Laudanski, Tadeusz; Pierzynski, Piotr

2006-01-01

In physiological research, we often study multivariate data sets, containing two or more simultaneously recorded time series. The aim of this paper is to present the cross-correlation and the wavelet cross-correlation methods to assess synchronization between contractions in different topographic regions of the uterus. From a medical point of view, it is important to identify time delays between contractions, which may be of potential diagnostic significance in various pathologies. The cross-correlation was computed in a moving window with a width corresponding to approximately two or three contractions. As a result, the running cross-correlation function was obtained. The propagation% parameter assessed from this function allows quantitative description of synchronization in bivariate time series. In general, the uterine contraction signals are very complicated. Wavelet transforms provide insight into the structure of the time series at various frequencies (scales). To show the changes of the propagation% parameter along scales, a wavelet running cross-correlation was used. At first, the continuous wavelet transforms as the uterine contraction signals were received and afterwards, a running cross-correlation analysis was conducted for each pair of transformed time series. The findings show that running functions are very useful in the analysis of uterine contractions.

PROBABILISTIC PROGRAMMING FOR ADVANCED MACHINE LEARNING (PPAML) DISCRIMINATIVE LEARNING FOR GENERATIVE TASKS (DILIGENT)

DTIC Science & Technology

2017-11-29

Structural connections of the frames (fragments) in the knowledge. We call the fundamental elements of the knowledge a limited number of elements...the result of contracted fundamental research deemed exempt from public affairs security and policy review in accordance with SAF/AQR memorandum dated...AVAILABILITY STATEMENT Approved for Public Release; Distribution Unlimited. This report is the result of contracted fundamental research deemed exempt from

Addressing the Barriers to Agile Development in the Department of Defense: Program Structure, Requirements, and Contracting

DTIC Science & Technology

2015-04-30

approach directly contrast with the traditional DoD acquisition model designed for a single big-bang waterfall approach (Broadus, 2013). Currently...progress, reduce technical and programmatic risk, and respond to feedback and changes more quickly than traditional waterfall methods (Modigliani...requirements, and contracting. The DoD can address these barriers by utilizing a proactively tailored Agile acquisition model , implementing an IT Box

Risk management. National Aeronautics and Space Administration (NASA). Interim rule adopted as final with changes.

PubMed

2000-11-22

This is a final rule amending the NASA FAR Supplement (NFS) to emphasize considerations of risk management, including safety, security (including information technology security), health, export control, and damage to the environment, within the acquisition process. This final rule addresses risk management within the context of acquisition planning, selecting sources, choosing contract type, structuring award fee incentives, administering contracts, and conducting contractor surveillance.

Structural and Chemical Properties of the Nitrogen-Rich Energetic Material Triaminoguanidinium 1-methyl-5-nitriminotetrazolate under Pressure

DTIC Science & Technology

2012-08-01

Source (NSLS) of Brookhaven National Laboratory ( BNL ). The syn- chrotron light is extracted from the VUV storage ring in a 40 × 40 mrad solid angle and...Contract No. DE-AC02-06CH11357. Infrared mea- surements were performed at the U2A beamline at the NSLS of BNL (DOE Contract No. DE-AC02-98CH10886). The

Fixed points of contractive mappings in b-metric-like spaces.

PubMed

Hussain, Nawab; Roshan, Jamal Rezaei; Parvaneh, Vahid; Kadelburg, Zoran

2014-01-01

We discuss topological structure of b-metric-like spaces and demonstrate a fundamental lemma for the convergence of sequences. As an application we prove certain fixed point results in the setup of such spaces for different types of contractive mappings. Finally, some periodic point results in b-metric-like spaces are obtained. Two examples are presented in order to verify the effectiveness and applicability of our main results.

Quaternary Expression of Northern Great Valley Faults and Folds: Accommodating North-South Contraction between the Sierran Microplate and Oregon Block

NASA Astrophysics Data System (ADS)

Angster, S.; Sawyer, T. L.; Wesnousky, S. G.

2015-12-01

The Northern California Shear Zone accommodates North American intraplate right-lateral transpressional shear driven by the relative motion of the northwest translating Sierran microplate. Within this zone, between the latitudes of 400 and 420, 1 - 4 mm/yr of north-south geodetic contraction is observed and for the most part remains geologically unaccounted for. We are investigating the Quaternary expression of transpressional shear localized at the northern end of the Sierra Nevada and Great Valley to evaluate both the recency and rates of deformation across structures that may be accommodating the contractional deformation suggested in geodetic studies. The northeast trending Inks Creek fold belt north of Red Bluff, CA consists of anticline-syncline pairs and dome structures that appear optimally oriented to accommodate northwest crustal shortening. The folds plunge to the southwest where they are incised and deflect the course of the Sacramento River. We will present preliminary geomorphic maps of fluvial terraces and drainage patterns associated with the folds constructed with standard field mapping techniques and aided by airborne LiDAR. It is anticipated that dating of deformed terrace strandlines with radiocarbon and OSL techniques holds the potential to quantify the lateral and vertical propagation rates of fold growth, as well as, constrain rates of regional contractional deformation.

Deciphering the impact of diagenesis overprint on negative δ13C excursions using rock magnetism: Case study of Ediacaran carbonates, Yangjiaping section, South China

NASA Astrophysics Data System (ADS)

Macouin, Mélina; Ader, Magali; Moreau, Marie-Gabrielle; Poitou, Charles; Yang, Zhenyu; Sun, Zhimming

2012-10-01

Rock magnetism is used here to investigate the genesis of one of the puzzling negative carbon isotopic excursions of the Neoproterozoic in the Yangtze platform (South China). A detailed characterization of the magnetic mineralogy, which includes low-temperature and high-field magnetometry and classical magnetic measurement (ARM, IRM, susceptibility), was therefore performed along upper Doushantuo and lower Dengying Formations outcropping in the Yangjiaping section. The derived magnetic parameters show variations that can be interpreted as variations in magnetic grains size and in oxide contents. They show that the magnetic content is significantly reduced in samples presenting negative δ13Ccalcite values. We interpret this as a result of magnetite dissolution and secondary carbonate precipitation during early diagenesis bacterial sulfate reduction. Combined with C and O isotopic data, paleomagnetic techniques thus show that the upper Doushantuo-lower Dengying negative excursion of the Yangjiaping section is largely due to diagenesis, although the preservation of a genuine δ13C excursion of lower magnitude from +7‰ down to 0‰, instead of down to -9‰ as usually considered, cannot be ruled out. A corrected δ13Ccarbonate chemostratigraphic curve is therefore proposed. The unambiguous identification of a strong diagenetic component for this excursion casts doubts on the primary nature of other potentially time equivalent negative excursions of the Yangtze platform and thus to its correlation to negative excursions in other cratons (i.e. Shuram excursion). More generally, this study illustrates the potential of magnetic mineralogy characterization, a low cost, time efficient and non-destructive technique, as screening tool for diagenetic overprints of δ13C and δ18O.

High-Pressure Granulite Facies Overprinting During the Exhumation of Eclogites in the Bangong-Nujiang Suture Zone, Central Tibet: Link to Flat-Slab Subduction

NASA Astrophysics Data System (ADS)

Zhang, Xiu-Zheng; Wang, Qiang; Dong, Yong-Sheng; Zhang, Chunfu; Li, Qing-Yun; Xia, Xiao-Ping; Xu, Wang

2017-12-01

The geometric transformation of a descending plate, such as from steep to flat subduction in response to a change from normal to overthickened oceanic crust during subduction, is a common and important geological process at modern or fossil convergent margins. However, the links between this process and the metamorphic evolution of the exhumation of oceanic (ultra)high-pressure eclogites are poorly understood. Here we report detailed petrological, mineralogical, phase equilibria, and secondary ion mass spectrometry zircon and rutile U-Pb age data for the Dong Co eclogites at the western segment of the Bangong-Nujiang suture zone, central Tibet. Our data reveal that the Dong Co eclogites experienced peak eclogite-facies metamorphism (T = 610-630°C, P = 2.4-2.6 GPa) and underwent multiple stages of retrograde metamorphism. P-T pseudosections and compositional isopleths of garnet define a complex clockwise P-T-t path (including two stages of decompression-dominated P-T path and one of isobaric heating), suggesting varying exhumation velocities. Combining previous studies with our new results, we suggest that the transformation from rapid to slow exhumation is dominated by the transition from steep to flat subduction. The flat-slab segment, caused by subduction of buoyant oceanic plateau, led to an extremely slow exhumation and a strong overprinting of HP granulite facies at a depth of 50 km at 177 Ma. The slab rollback that followed in response to a substantial density increase of the eclogitized oceanic plateau resulted in another rapid exhumation process at 168 Ma and triggered the formation of abundant near-simultaneous or later magmatic rocks.

Pseudoimpactites in anthropocenically overprinted quaternary sediments

NASA Astrophysics Data System (ADS)

Huber, Robert; Darga, Robert; Lauterbach, Hans

2017-04-01

Whereas typical anthropogenic materials such as plastics can easily be identified in the anthropocene record, other materials such as building materials or industrial waste often closely resemble natural rocks or minerals. Especially transported and weathered anthropocenic matter is hard to distinguish from natural rocks. Whereas most rock samples may easily be distinguished by visual inspection, definite identification of exotic and small sized matter is not always an easy exercise which has been shown during the controversial discussion on the cosmic origin of carbon spherules found in Younger Dryas sediments. Similarly, a variety of exotic materials and lithological phenomena reported from quaternary sediments in Upper Bavaria have been associated to a cosmic impact in the area. Findings of carbonatic regmaglypts, glass coated and fragmented rocks, glassy carbon or pumice like carbon have been proposed to represent impact related rocks, an hypothesis which has further been supported by findings of iron silicides and the postulated detection of nanodiamonds and Carbine. Many of these findings have been strongly doubted within the geoscientific community, however a systematic, independent investigation of these phenomena has not yet been conducted. We present the results of our examinations which have been carried out to critically test the impact related origin of the mentioned strange materials and rocks. We could identify some key sites and independently collected samples of several of the materials and analysed these thoroughly. We found that the majority of these impact related materials is of anthropogenic or biogenic origin, thus they are pseudoimpactites partly originating from old fireplaces and waste pits. The claimed cosmic origin of this matter is an illusion caused by the anthropocene overprint of the original sedimentary record.

Field and experimental evidence for coseismic ruptures along shallow creeping faults in forearc sediments of the Crotone Basin, South Italy

NASA Astrophysics Data System (ADS)

Balsamo, Fabrizio; Aldega, Luca; De Paola, Nicola; Faoro, Igor; Storti, Fabrizio

2014-05-01

Large seismic slip occurring along shallow creeping faults in tectonically active areas represents an unsolved paradox, which is largely due to our poor understanding of the mechanics governing creeping faults, and to the lack of documented geological evidence showing how coseismic rupturing overprints creep in near-surface conditions. In this contribution we integrate field, petrophysical, mineralogical and friction data to characterize the signature of coseismic ruptures propagating along shallow creeping faults affecting unconsolidated forearc sediments of the seismically active Crotone Basin, in South Italy. Field observations of fault zones show widespread foliated cataclasites in fault cores, locally overprinted by sharp slip surfaces decorated by thin (0.5-1.5 cm) black gouge layers. Compared to foliated cataclasites, black gouges have much lower grain size, porosity and permeability, which may have facilitated slip weakening by thermal fluid pressurization. Moreover, black gouges are characterized by distinct mineralogical assemblages compatible with high temperatures (180-200°C) due to frictional heating during seismic slip. Foliated cataclasites and black gouges were also produced by laboratory friction experiments performed on host sediments at sub-seismic (≤ 0.1 m/s) and seismic (1 m/s) slip rates, respectively. Black gouges display low friction coefficients (0.3) and velocity-weakening behaviours, as opposed to high friction coefficients (0.65) and velocity-strengthening behaviours shown by the foliated cataclasites. Our results show that narrow black gouges developed within foliated cataclasites represent a potential diagnostic marker for episodic seismic activity in shallow creeping faults. These findings can help understanding the time-space partitioning between aseismic and seismic slip of faults at shallow crustal levels, impacting on seismic hazard evaluation of subduction zones and forearc regions affected by destructive earthquakes and tsunamis.

Origin of Zn-Pb-Sb-Au mineralization adjacent to the Paleoproterozoic Boliden Au-rich VMS deposit, Sweden: evidence from petrographic and oxygen isotope characteristics

NASA Astrophysics Data System (ADS)

Adomako-Ansah, Kofi; Ishiyama, Daizo; Allen, Rodney

2018-06-01

Adjacent to the world-class Boliden deposit, fine- to coarse-grained Zn-Pb-Sb-Au-rich sulfide-sulfosalt-bearing horizons occur within the base of a metasedimentary succession that has previously been regarded to stratigraphically overlie the Skellefte Volcanics and Boliden deposit. The metasedimentary succession comprises interbedded mudstone and normal-graded crystal-rich volcanic sandstone-siltstone units, interpreted to be low-density turbidity currents in a subaqueous environment below wave base. The sharp contact between the mineralized intervals and volcanic sandstone is concordant to the bedding planes and compaction foliation. Above and below the mineralization, the wall rocks contain well-preserved plagioclase crystals, partly enclosed by a weak alteration composed of bedding-parallel metamorphic biotite±sericite minerals. These observations are consistent with burial (or tectonic) compaction and diagenetic alteration that was overprinted by metamorphic biotite. The occurrence of biotite in the wall rocks and homogenization recrystallization of the sulfide-sulfosalt assemblage in the mineralized intervals are consistent with peak metamorphic conditions ( 350-450 °C, < 4 kbars) in the Boliden area. However, preservation of plagioclase and water-rock interaction under rock-dominant conditions suggest that high δ18O values (+ 10.7 to + 13.5‰) acquired during diagenesis were unchanged by the metamorphic overprint. The δ18O values yield low temperatures (< 150 °C), which indicate pre-metamorphic conditions. These data suggest that the Zn-Pb-Sb-Au-rich intervals formed as pre-metamorphic distal syn-volcanic exhalative mineralization during sedimentation of the Vargfors group metasedimentary rocks. This implies that massive sulfide formation continued even during Vargfors group time and, therefore, there is still potential for discovery of gold-rich base-metal ores in this part of the Skellefte field stratigraphy.

Eclogites and garnet pyroxenites from Kimberley, Kaapvaal craton, South Africa: their diverse origins and complex metasomatic signatures

NASA Astrophysics Data System (ADS)

Shu, Qiao; Brey, Gerhard P.; Pearson, D. Graham

2018-06-01

We describe the petrography and mineral chemistry of sixteen eclogite and garnet pyroxenite xenoliths from the reworked Boshof road dump (Kimberley) and define three groups that stem from different depths. Group A, the shallowest derived, has low HREE (heavy rare earth element) abundances, flat middle to heavy REE patterns and high Mg# [= 100·Mg/(Mg + Fe)]. Their protoliths probably were higher pressure cumulates ( 0.7 GPa) of mainly clinopyroxene (cpx) and subordinate orthopyroxene (opx) and olivine (ol). Group B1 xenoliths, derived from the graphite/diamond boundary and below show similarities to present-day N-MORB that were modified by partial melting (higher Mg# and positively inclined MREE (middle REE) and HREE (heavy REE) patterns of calculated bulk rocks). Group B2 samples from greatest depth are unique amongst eclogites reported so far worldwide. The calculated bulk rocks have humped REE patterns with very low La and Lu and prominent maxima at Sm or Eu and anomalously high Na2O (up to 5 wt%) which makes protolith identification difficult. The complex trace element signatures of the full spectrum of Kimberley eclogites belie a multi-stage history of melt depletion and metasomatism with the introduction of new phases especially of phlogopite (phlog). Phlogopite appears to be characteristic for Kimberley eclogites and garnet peridotites. Modelling the metasomatic overprint indicates that groups A and B1 were overprinted by volatile- and potassium-rich melts probably by a process of chromatographic fractionation. Using constraints from other metasomatized Kimberley mantle rocks suggest that much of the metasomatic phlogopite in the eclogites formed during an intense episode of metasomatism that affected the mantle beneath this region 1.1 Gyr ago.

Mapped minerals at Questa, New Mexico, using airborne visible-infrared imaging spectrometer (AVIRIS) data -- Preliminary report

USGS Publications Warehouse

Livo, K. Eric; Clark, Roger N.

2002-01-01

This preliminary study for the First Quarterly Report has spectrally mapped hydrothermally altered minerals useful in assisting in assessment of water quality of the Red River. Airborne Visible-Infrared Imaging Spectrometer (AVIRIS) data was analyzed to characterize mined and unmined ground at Questa, New Mexico. AVIRIS data covers the Red River drainage north of the river, from between the town of Questa on the west, to east of the town of Red River. The data was calibrated and analyzed using U.S. Geological Survey custom software and spectral mineral library. AVIRIS data was tested for spectral features that matched similar features in the spectral mineral library. Goodness-of-fit and band-depth were calculated for each comparison of spectral features and used to identify surface mineralogy. Mineral distribution, mineral associations, and AVIRIS pixel spectra were examined. Mineral maps show the distribution of iron hydroxides, iron sulfates, clays, micas, carbonates, and other minerals. Initial results show a system of alteration suites that overprint each other. Quartz-sericite-pyrite (QSP) alteration grading out to propylitic alteration (epidote and calcite) was identified at the Questa Mine (molybdenum porphyry) and a similar alteration pattern was mapped at the landslide (?scar?) areas. Supergene weathering overprints the altered rock, as shown by jarosite, kaolinite, and gypsum. In the spectral analysis, hydrothermally altered ground appears to be more extensive at the unmined Goat Hill Gulch and the mined ground, than the ?scars? to the east. Though the ?scars? have similar overall altered mineral suites, there are differences between the ?scars? in sericite, kaolinite, jarosite, gypsum, and calcite abundance. Fieldwork has verified the results at the central unmined ?scar? areas.

The Influence of Terrestrial Environment on Meteorite Magnetic Records

NASA Astrophysics Data System (ADS)

Kohout, T.; Kletetschka, G.; Kobr, M.; Pruner, P.; Wasilewski, P. J.

2003-04-01

In early solar system history there are several electromagnetic processes expected that may be capable of magnetizing the primitive solid particles condensating from the Solar Nebula. The record of these magnetic events can be observed during laboratory studies of meteorites found on the Earth. Different terrestrial processes can affect the magneto mineralogy, can cause changes in magnetic parameters, and can overprint the primary magnetic record. The effect of surface heating (when falling through the atmosphere) was the subject of the study with the Murchison meteorite. Using the Allende meteorite we studied the effect of the shock pressure generated by the friction of the atmosphere during the meteorite fall. Some of the meteorites are found several days after the fall, some of them are deposited in the desert or on the Antarctic ice for thousands of years. Most of them contain visible traces of terrestrial oxidation and weathering. We used the sample of the LL chondrite found in the Libya desert (perhaps thousands years ago), sample of the iron meteorite Campo del Cielo (found in Argentina 5000 years after the fall), and sample of the H 5 Zebrak meteorite (found only several days after the fall) for weathering simulations. To document the results of our experiments we used low and high temperature measurements of magnetic susceptibility, measurements of magnetic remanence and its stability and hysteresis parameters. The results tell us, that the terrestrial processes are efficient factor in changing magnetic properties and can overprint the primary magnetic record. Therefore extreme care has to be taken when selecting samples for primary magnetic component study. Acknowledgements: This work is supported by Charles University Grant Agency, Czech Republic and would not be possible without the help of following people: Jakub Haloda, Petr Jakes, Marcela Bukovanska, Jaroslav Kadlec, Libuse Kohoutova, Vladimir Kohout.

Inconsistent magnetic polarities in magnetite- and greigite-bearing sediments: Understanding complex magnetizations in the late Messinian in the Adana Basin (southern Turkey)

NASA Astrophysics Data System (ADS)

Lucifora, Stella; Cifelli, Francesca; Mattei, Massimo; Sagnotti, Leonardo; Cosentino, Domenico; Roberts, Andrew P.

2012-10-01

We present paleomagnetic, rock magnetic and scanning electron microscope data from three upper Messinian stratigraphic sections from the Adana Basin (southern Turkey). The collected samples are from fine-grained units, which were deposited during the Messinian Salinity Crisis (within subchron C3r). Paleomagnetic results reveal an inconsistent polarity record, related to a mixture of magnetite and greigite that hinders determination of a reliable magnetostratigraphy. Three classes of samples are recognized on the basis of paleomagnetic results. The first is characterized by a single magnetization component, with normal polarity, that is stable up to 530-580°C and is carried by magnetite. The second is characterized by a single magnetization component, with reversed polarity, that is stable up to 330-420°C. This magnetization is due to greigite, which developed after formation of slumps and before tectonic tilting of the studied successions. The third is characterized by reversed polarity, which is stable up to 530-580°C. We interpret this component as a primary magnetization carried by fine-grained and magnetically stable detrital magnetite. Results indicate that in the Adana Basin the assumption that a primary magnetization is carried by magnetite, and a magnetic overprint carried by greigite, does not hold because a late magnetic overprint has also been found for magnetite-bearing samples. Our data illustrate the complexity of magnetostratigraphic reconstructions in successions characterized by variable mixtures of magnetic minerals with different magnetic stability that formed at different stages. We demonstrate the need to perform detailed magnetic mineralogy analyses when conducting magnetostratigraphic studies of clay-rich sediments from marine or lacustrine environments.

Genetics Home Reference: early-onset myopathy with fatal cardiomyopathy

MedlinePlus

... they are made of proteins that generate the mechanical force needed for muscles to contract. Titin has several functions within sarcomeres. One of this protein's most important jobs is to provide structure, flexibility, and stability to these cell structures. Titin ...

Fundamental Structure of High-Speed Reacting Flows: Supersonic Combustion and Detonation

DTIC Science & Technology

2016-04-30

AFRL-AFOSR-VA-TR-2016-0195 Fundamental Structure of High-Speed Reacting Flows: Supersonic Combustion and Detonation Kenneth Yu MARYLAND UNIV COLLEGE...MARCH 2016 4. TITLE AND SUBTITLE FUNDAMENTAL STRUCTURE OF HIGH-SPEED REACTING FLOWS: SUPERSONIC COMBUSTION AND DETONATION 5a. CONTRACT NUMBER...public release. Final Report on Fundamental Structure of High-Speed Reacting Flows: Supersonic Combustion and Detonation Grant

Vibration Attenuation of the NASA Langley Evolutionary Structure Experiment Using H(infinity) and Structured Singular Value (mu) Robust Multivariable Control Techniques

NASA Technical Reports Server (NTRS)

Balas, Gary J.

1996-01-01

This final report summarizes the research results under NASA Contract NAG-1-1254 from May, 1991 - April, 1995. The main contribution of this research are in the areas of control of flexible structures, model validation, optimal control analysis and synthesis techniques, and use of shape memory alloys for structural damping.

Large-scale recumbent isoclinal folds in the footwall of the West Cycladic Detachment System (Greece)

NASA Astrophysics Data System (ADS)

Rice, A. Hugh N.; Grasemann, Bernhard

2017-04-01

The Pindos Zone in the Cyclades underwent Eocene high-pressure metamorphism and syn-orogenic exhumation, overprinted by Miocene low-angled extension. Although this represents a combination of likely high-strain-events, structural evidence of large-scale folding is rare. Here potential examples of such folding on Kea and Kythnos, in the Western Cyclades, are evaluated. These islands lie within the Cycladic Blueschist Nappe (lower nappe) of the Pindos Zone and in the footwall of the top-to-SSW West Cycladic Detachment System (WCDS). On Kea, no lithostratigraphy can be established in the 450 m thick greenschist facies mixed sedimentary-volcanoclastic-marble mylonite/phyllonite succession. On the east side of the island, lensoid marble layers frequently bifurcate, which might be reflecting early, sheared-out isoclinal folding, although no evidence of folded compositional layering has been found in potential fold-hinge zones and the bifurcation points are not arranged in a way suggestive of a fold axes parallel to the NNE-SSW oriented stretching lineation. However, at two localities, medium-scale recumbent isoclinal folding has been mapped, with NNE-SSW fold-axes exposed for up to 250 m and amplitudes of up to 170 m. On Kythnos, stretching lineations in greenschist facies rocks show a rotation from ENE-WSW in the north to NNE-SSW in the south, taken to represent a reorientation of the Eocene exhumation strain during block rotation coincident with top-to-SSW movement of the WCDS. The distribution of the three marble units that crop out in central/southern Kythnos suggest large-scale, likely isoclinal folding occurred. (1) Petroussa Lithodeme - a blue-grey calcite (BGC) marble with quartz-calcite-white-mica (QCWM) schists, forming a continuous outcrop around the island, thinning from >16m in the SE to <8m thick mylonites in the SW, overlain by grey sericite-albite-graphite-schists (Flabouria Lithodeme); (2) Rizou Lithodeme - massive grey to BGC marble, with abundant quartz layers, only cropping out above the Flabouria Lithodeme south of Aghios Dimitrios, directly below the WCDS; (3) Mavrianou Lithodeme - mylonitic QCWM schists with lenses of BGC mylonites cropping out above the Flabouria Lithodeme along the west coast, 2.5-9 km N of Aghios Dimitrios. Thus, offshore in the 2.5 km north of Aghios Dimitrios, the Mavrianou Lithodeme is 'replaced' by the Rizou Lithodeme; these units are lithologically quite distinct. However, mylonitic outcrops of the Petroussa Lithodeme are very similar to the Mavrianou Lithodeme mylonites. A tentative structural solution is to argue that the Mavrianou Lithodeme is a large-scale isoclinal fold repetition of the Petroussa Lithodeme; southwards the fold amplitude decreases and dies out offshore north of Aghios Dimitrios; repetition of other lithodemes supports this solution. The origin of the fold is not known but the lithological repetition persists towards the central part of the island, where the transition from ENE-WSW trending Eocene exhumation deformation has not been fully overprinted by NNE-SSW trending Miocene deformation. Hence the fold may have formed as a large-scale structure during syn-orogenic Eocene exhumation of the Cycladic Blueschist Nappe and then been flattened and rotated during Miocene deformation in the footwall of the West Cycladic Detachment System.

An Assessment of Private General Practitioners Contracting for Public Health Services Delivery in O.R. Tambo District, South Africa

PubMed Central

Hongoro, Charles; Funani, I Itumeleng N.; Chitha, Wezile; Godlimpi, Lizo

2015-01-01

Low- and middle-income countries are striving towards universal health coverage in a variety of ways. Achieving this goal requires the participation of both public and the private sector providers. The study sought to assess existing capacity for independent general practitioner contracting in primary care, the reasons for the low uptake of government national contract and the expectations of general practitioners of such contractual arrangements. This was a case study conducted in a rural district of South Africa. The study employed both quantitative and qualitative data collection methods. Data were collected using a general practitioner and practice profiling tool, and a structured questionnaire. A total of 42 general practitioners were interviewed and their practices profiled. Contrary to observed low uptake of the national general practitioner contract, 90% of private doctors who had not yet subscribed to it were actually interested in it. Substantial evidence indicated that private doctors had the capacity to deliver quality care to public patients. However, low uptake of national contarct related mostly to lack of effective communication and consultation between them and national government which created mistrust and apprehension amongst local private doctors. Paradoxically, these general practitioners expressed satisfaction with other existing state contracts. An analysis of the national contract showed that there were likely to benefit more from it given the relatively higher payment rates and the guaranteed nature of this income. Proposed key requisites to enhanced uptake of the national contract related to the type of the contract, payment arrangements and flexibility of the work regime, and prospects for continuous training and clinical improvements. Low uptake of the national General Practitioner contract was due to variety of factors related to lack of understanding of contract details. Such misunderstandings between potential contracting parties created mistrust and apprehension, which are fundamental antitheses of any effective contractual arrangement. The idea of a one-size-fits-all contract was probably inappropriate. PMID:28299145

FAST CONTRACTION OF CORONAL LOOPS AT THE FLARE PEAK

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

Liu Rui; Wang Haimin

On 2005 September 8, a coronal loop overlying the active region NOAA 10808 was observed in TRACE 171 A to contract at {approx}100 km s{sup -1} at the peak of an X5.4-2B flare at 21:05 UT. Prior to the fast contraction, the loop underwent a much slower contraction at {approx}6 km s{sup -1} for about 8 minutes, initiating during the flare preheating phase. The sudden switch to fast contraction is presumably corresponding to the onset of the impulsive phase. The contraction resulted in the oscillation of a group of loops located below, with the period of about 10 minutes. Meanwhile,more » the contracting loop exhibited a similar oscillatory pattern superimposed on the dominant downward motion. We suggest that the fast contraction reflects a suddenly reduced magnetic pressure underneath due either to (1) the eruption of magnetic structures located at lower altitudes or to (2) the rapid conversion of magnetic free energy in the flare core region. Electrons accelerated in the shrinking trap formed by the contracting loop can theoretically contribute to a late-phase hard X-ray burst, which is associated with Type IV radio emission. To complement the X5.4 flare which was probably confined, a similar event observed in SOHO/EIT 195 A on 2004 July 20 in an eruptive, M8.6 flare is briefly described, in which the contraction was followed by the expansion of the same loop leading up to a halo coronal mass ejection. These observations further substantiate the conjecture of coronal implosion and suggest coronal implosion as a new exciter mechanism for coronal loop oscillations.« less

Spatiotemporal mapping of the muscular activity of the gizzard of the chicken (Gallus domesticus).

PubMed

Lentle, R G; Reynolds, G; de Loubens, C; Hulls, C; Janssen, P W M; Ravindran, V

2013-02-01

We report the results of spatiotemporal mapping of the spontaneous actions of component muscles of the gizzard and associated structures in ex vivo preparations with combined superfusion and vascular perfusion. Ongoing spontaneous contraction of cranial and caudal thin muscles occurred at a frequency of 2.2 ± 0.1 cycles per minute. Contractions of M. tenuis craniodorsalis with mean duration of 2.8 ± 0.2 s commenced ventrally adjacent to the distal limit of the proventriculus and progressed dorsally at 2.02 ± 0.03 mm•s(-1) in a concerted front. Near simultaneous contraction of M. tenuis caudoventralis of mean duration of contraction of 4.7 ± 0.7 s commenced dorsally and progressed ventrally at a similar rate (2.1 ± 0.1 mm•s(-1)) and in a similar manner. Contraction of the caudoventralis preceded that of craniodorsalis (mean 1.1 ± 0.15 s). Contraction of the 2 tenuis muscles was synchronous with the first component peak of the cyclic increase in lumen pressure and with distension of the crassus musculature. Contraction of the M. crassus caudodorsalis muscle coincided with the second component peak and was followed by distension of the tenuis musculature. The latter commenced before the relaxation of the tenuis muscles. Contractions of the crassus muscle propagated rapidly at right angles to the orientation of the muscle fibers at a faster velocity than that of the tenuis musculature. The durations of the component peaks in lumen pressure indicated that the duration of crassus contraction was similar to that of the tenuis musculature.

Iron isotopic systematics of pyroxenite xenoliths from North China Craton: implications for Melt-rock interaction in the sub-continental lithospheric mantle beneath eastern China

NASA Astrophysics Data System (ADS)

Zhao, X.; Cao, H.; Yu, H.; Huang, F.

2016-12-01

Iron isotope systems have become widely used tools in high temperature geochemistry and provide important constraints on mantle dynamics. Here, we report Fe isotopic data on a series of pyroxenite xenoliths from Hannuoba, North China Craton to further constrain the Fe isotopic composition of the mantle and investigate the behavior of Fe isotopes during mantle processes. These xenoliths range from Cr- pyroxenites, Al-pyroxenites to garnet pyroxenites, and are taken as physical evidence for different episodes of melt injection events. Our results show that both Cr- pyroxenites and Al-pyroxenites have a narrow range of Fe isotopes (δ57Fe=-0.01 to 0.09), similar to that reported typical mantle peridotites and they show equilibrium inter-mineral Fe isotope fractionation between coexisting mantle minerals. In contract, the garnet pyroxenites, which are products of reaction between a silicate melt and peridotite, exhibit larger Fe isotopic variations, with δ57Fe ranging from 0.08 to 0.30. The δ57Fe values of minerals in these garnet pyroxenites also vary widely from -0.25 to -0.03 in olivines, from -0.04 to 0.14 in orthopyroxenes, from -0.07 to 0.31 in clinopyroxenes, from 0.07 to 0.26 in spinels and from 0.30 to 0.39 in garnets. These observed data stand in marked contrast to the calculated equilibrium Fe isotope fractionation between coexisting mantle minerals at mantle temperature from theory, indicating disequilibrium isotope fractionation. The disequilibrium isotope fractionations between coexisting mantle minerals in garnet pyroxenites most likely reflect kinetic isotope fractionation during melt-peridotite interaction. In addition, the phlogopite clinopyroxenite with an apparent metasomatic overprint has the heaviest δ57Fe (as high as 1.00) but lightest δ26Mg (as low as -1.50) values of the investigated samples. Our study shows that mantle metasomatism plays an important role in producing Fe isotopic heterogeneity of the subcontinental mantle.

Time-evolving bubbles in two-dimensional stokes flow

NASA Technical Reports Server (NTRS)

Tanveer, Saleh; Vasconcelos, Giovani L.

1994-01-01

A general class of exact solutions is presented for a time evolving bubble in a two-dimensional slow viscous flow in the presence of surface tension. These solutions can describe a bubble in a linear shear flow as well as an expanding or contracting bubble in an otherwise quiescent flow. In the case of expanding bubbles, the solutions have a simple behavior in the sense that for essentially arbitrary initial shapes the bubble will asymptote an expanding circle. Contracting bubbles, on the other hand, can develop narrow structures ('near-cusps') on the interface and may undergo 'break up' before all the bubble-fluid is completely removed. The mathematical structure underlying the existence of these exact solutions is also investigated.

Review and Recommendations for the Interagency Ship Structure Committee’s Fiscal 1984 Research Program,

DTIC Science & Technology

1983-01-01

Daily. Proposal Evaluation Procedure Organizations interested in doing the work adverstised submit proposals and cost estimates. The USCG contracting...types of offshore structures. These structures have largely been fixed platforms for petroleum drilling and production, and mobile offshore drilling...structures and of those mobile drilling units that are bottom supported, such as jack-ups and submersibles. Structures which are held in place by anchors

7 CFR 51.56 - Buildings and structures.

Code of Federal Regulations, 2010 CFR

2010-01-01

... its distribution throughout the plant and washing machinery; (c) There shall also be an efficient... STANDARDS) Regulations 1 Requirements for Plants Operating Under Continuous Inspection on A Contract Basis § 51.56 Buildings and structures. The packing plant buildings shall be properly constructed and...

[Health status comparative analysis of the emercom of Russia Federal fire service employees and contract servicemen in the Russian Army].

PubMed

Koteev, P K; Kireev, S G; Golovinova, V Iu

2013-08-01

Results of health status comparative analysis of the emercom of Russia Federal fire service employees and contract servicemen in the Russian Army are submitted as following. The emercom of russia firemen's average annual rate of primary morbidity is 459,1, that of labor losses' days 8430,8, of disability 0,9, and mortality cases 0,7. The russian army contract servicemen's average annual rate of primary morbidity during the covered period comes to 410,3, that of discharges 7,4, and mortality cases 1,3. The results of comparative analysis show that the rate of contract servicemen's primary morbidity is lower than that of emercom of Russia firemen below 10.6% (p < 0.001), whereas their discharge level is higher above 87% (p < 0.001). In the course of comparison of the emercom of Russia Federal fire service employees' and the Russian Army contract servicemen's primary morbidity structure it was revealed that the indexes of the diseases of respiratory system, traumas and poisoning are higher among the first ones. On the contrary, their indexes were lower in the sphere of circulatory system, skin and hypodermic cellulose diseases. The indexes of circulatory system diseases in the disability (discharge level) structure of the emercom of Russia Federal fire service employees were higher than those of other diseases. It is expedient to use the results of this research in forming of priority assignments and conducting of a complex of curative and prophylactic measures organized by the medical service of the emercom of Russia.

Assessment of brain activity during voluntary anal sphincter contraction: Comparative study in women with and without fecal incontinence.

PubMed

Parés, D; Martínez-Vilalta, M; Ortiz, H; Soriano-Mas, C; Maestre-Gonzalez, Y; Pujol, J; Grande, L

2018-04-14

Voluntary anal sphincter function is driven by an extended network of brain structures, most of which are still unknown. Disturbances in this function may cause fecal incontinence. The aim of this study was to characterize the cerebral areas involved in voluntary contraction of the anorectal sphincter in healthy women and in a group of patients with fecal incontinence by using a standardized functional magnetic resonance imaging (fMRI) protocol. This comparative study included 12 healthy women (mean age 53.17 ± 4.93 years) and 12 women with fecal incontinence (56.25 ± 6.94 years). An MRI-compatible anal manometer was used to register voluntary external anal sphincter contraction. During brain fMRI imaging, participants were cued to perform 10-s series of self-paced anal sphincter contractions at an approximate rate of 1 Hz. Brain structures linked to anal sphincter contractions were mapped and the findings were compared between the 2 study groups. There were no differences in the evoked brain activity between the 2 groups. In healthy women, group fMRI analysis revealed significant activations in medial primary motor cortices, supplementary motor area, bilateral putamen, and cerebellum, as well as in the supramarginal gyrus and visual areas. In patients with fecal incontinence, the activation pattern involved similar regions without significant differences with healthy women. This brain fMRI-anorectal protocol was able to map the brain regions linked to voluntary anal sphincter function in healthy and women with fecal incontinence. © 2018 John Wiley & Sons Ltd.

Standard Port-Visit Cost Forecasting Model for U.S. Navy Husbanding Contracts

DTIC Science & Technology

2009-12-01

Protocol (HTTP) server.35 2. MySQL . An open-source database.36 3. PHP . A common scripting language used for Web development.37 E. IMPLEMENTATION OF...Inc. (2009). MySQL Community Server (Version 5.1) [Software]. Available from http://dev.mysql.com/downloads/ 37 The PHP Group (2009). PHP (Version...Logistics Services MySQL My Structured Query Language NAVSUP Navy Supply Systems Command NC Non-Contract Items NPS Naval Postgraduate

Fixed Points of Contractive Mappings in b-Metric-Like Spaces

PubMed Central

Hussain, Nawab; Roshan, Jamal Rezaei

2014-01-01

We discuss topological structure of b-metric-like spaces and demonstrate a fundamental lemma for the convergence of sequences. As an application we prove certain fixed point results in the setup of such spaces for different types of contractive mappings. Finally, some periodic point results in b-metric-like spaces are obtained. Two examples are presented in order to verify the effectiveness and applicability of our main results. PMID:25143980

A New ’Availability-Payment’ Model for Pricing Performance-Based Logistics Contracts

DTIC Science & Technology

2014-04-30

maintenance network connected to the inventory and Original Equipment Manufacturer (OEM) used in this paper. The input to the Petri net in Figure 2 is the...contract structures. The model developed in this paper uses an affine controller to drive a discrete event simulator ( Petri net ) that produces...discrete event simulator ( Petri net ) that produces availability and cost measures. The model is used to explore the optimum availability assessment

Bistable Vertical-Cavity Surface-Emitting Laser. Structures on GaAs and Si Substrates

DTIC Science & Technology

1994-06-01

vertical - cavity surface - emitting lasers ( VCSELs ) [1,5,6 of publications below], fabrication processes to realize low...May 91 through 1 June 94 R&T Number: Contract / Grant Number: N00014-91-J-1952 Contract / Grant Title: Bistable Vertical - Cavity Surface - Emitting Laser ...T.J. Rogers, B.G. Streetman, S.C. Smith, and R.D. Burnham, "Cascadabity of an Optically Iathing Vertical - Cavity Surface - Emitting Laser

On the convergence of an iterative formulation of the electromagnetic scattering from an infinite grating of thin wires

NASA Technical Reports Server (NTRS)

Brand, J. C.

1985-01-01

Contraction theory is applied to an iterative formulation of electromagnetic scattering from periodic structures and a computational method for insuring convergence is developed. A short history of spectral (or k-space) formulation is presented with an emphasis on application to periodic surfaces. The mathematical background for formulating an iterative equation is covered using straightforward single variable examples including an extension to vector spaces. To insure a convergent solution of the iterative equation, a process called the contraction corrector method is developed. Convergence properties of previously presented iterative solutions to one-dimensional problems are examined utilizing contraction theory and the general conditions for achieving a convergent solution are explored. The contraction corrector method is then applied to several scattering problems including an infinite grating of thin wires with the solution data compared to previous works.

Associations Between Fixed-Term Employment and Health and Behaviors: What are the Mechanisms?

PubMed

Żołnierczyk-Zreda, Dorota; Bedyńska, Sylwia

2018-03-01

To analyze the associations between fixed-term employment and health (work ability and mental health) and behaviors (engagement and performance). Psychological contract fulfilment (PCF) and breach (PCB) are investigated as potential mediators of these associations. Seven hundred workers employed on fixed-term contracts from a broad range of organizations participated in the study. The Structural Equation Model was performed to analyze the data. Mediation analyses revealed that good physical and mental health and productivity are more likely to be achieved by those workers who perform non-manual work and (to some extent) accept their contracts because they experience high levels of PCF and low levels of PCB. Apart from the lack of physical workload, psychological contract fulfilment has been revealed as yet another significant mediator between a higher socioeconomic position and good health and productivity of fixed-term workers.

Design of inventory pools in spare part support operation systems

NASA Astrophysics Data System (ADS)

Mo, Daniel Y.; Tseng, Mitchell M.; Cheung, Raymond K.

2014-06-01

The objective of a spare part support operation is to fulfill the part request order with different service contracts in the agreed response time. With this objective to achieve different service targets for multiple service contracts and the considerations of inventory investment, it is not only important to determine the inventory policy but also to design the structure of inventory pools and the order fulfilment strategies. In this research, we focused on two types of inventory pools: multiple inventory pool (MIP) and consolidated inventory pool (CIP). The idea of MIP is to maintain separated inventory pools based on the types of service contract, while CIP solely maintains a single inventory pool regardless of service contract. Our research aims to design the inventory pool analytically and propose reserve strategies to manage the order fulfilment risks in CIP. Mathematical models and simulation experiments would be applied for analysis and evaluation.

Advanced Technology Composite Fuselage-Structural Performance

NASA Technical Reports Server (NTRS)

Walker, T. H.; Minguet, P. J.; Flynn, B. W.; Carbery, D. J.; Swanson, G. D.; Ilcewicz, L. B.

1997-01-01

Boeing is studying the technologies associated with the application of composite materials to commercial transport fuselage structure under the NASA-sponsored contracts for Advanced Technology Composite Aircraft Structures (ATCAS) and Materials Development Omnibus Contract (MDOC). This report addresses the program activities related to structural performance of the selected concepts, including both the design development and subsequent detailed evaluation. Design criteria were developed to ensure compliance with regulatory requirements and typical company objectives. Accurate analysis methods were selected and/or developed where practical, and conservative approaches were used where significant approximations were necessary. Design sizing activities supported subsequent development by providing representative design configurations for structural evaluation and by identifying the critical performance issues. Significant program efforts were directed towards assessing structural performance predictive capability. The structural database collected to perform this assessment was intimately linked to the manufacturing scale-up activities to ensure inclusion of manufacturing-induced performance traits. Mechanical tests were conducted to support the development and critical evaluation of analysis methods addressing internal loads, stability, ultimate strength, attachment and splice strength, and damage tolerance. Unresolved aspects of these performance issues were identified as part of the assessments, providing direction for future development.

Characterization of the chemical structure and innate immune-stimulating activity of an extracellular polysaccharide from Rhizobium sp. strain M2 screened using a silkworm muscle contraction assay.

PubMed

Urai, Makoto; Aizawa, Tomoko; Imamura, Katsutoshi; Hamamoto, Hiroshi; Sekimizu, Kazuhisa

2017-11-22

We screened innate immunostimulant-producing bacteria using a silkworm muscle contraction assay, and isolated Rhizobium sp. strain M2 from soil. We purified the innate immunostimulant from strain M2, and characterized the chemical structure by nuclear magnetic resonance spectroscopy and chemical analyses. The innate immunostimulant (M2 EPS) comprised glucose, galactose, pyruvic acid, and succinic acid with a molar ratio of 6.8:1.0:0.9:0.4, and had a succinoglycan-like high molecular-weight heteropolysaccharide structure. To determine the structural motif involved in the innate immunostimulating activity, we modified the M2 EPS structure chemically, and found that the activity was increased by removal of the succinic and pyruvic acid substitutions. Strong acid hydrolysis completely inactivated the M2 EPS. Unmasking of the β-1,3/6-glucan structure of the side-chain by deacylation and depyruvylation may enhance the innate immune-stimulating activity of M2 EPS. These findings suggest that the succinoglycan-like polysaccharide purified from strain M2 has innate immune-stimulating activity, and its glycan structure is necessary for the activity.

Effects of aluminum hinged shoes on the structure of contracted feet in Thoroughbred yearlings.

PubMed

Tanaka, Kousuke; Hiraga, Atsushi; Takahashi, Toshiyuki; Kuwano, Atsutoshi; Morrison, Scott Edward

2015-01-01

We applied aluminum hinged shoes (AHSs) to the club foot-associated contracted feet of 11 Thoroughbred yearlings to examine the effects of the shoes on the shape of the hoof and third phalanx (P III). After 3 months of AHS use, the size of the affected hooves increased significantly, reaching the approximate size of the healthy contralateral hooves with respect to the maximum lateral width of the foot, the mean ratio of the bearing border width to the coronary band width, and the mean ratio of the solar surface width to the articular surface width. These results suggest that the AHSs corrected the contracted feet in these yearling horses.

Airborne electromagnetic and magnetic survey data of the Paradox and San Luis Valleys, Colorado

USGS Publications Warehouse

Ball, Lyndsay B.; Bloss, Benjamin R.; Bedrosian, Paul A.; Grauch, V.J.S.; Smith, Bruce D.

2015-01-01

In October 2011, the U.S. Geological Survey (USGS) contracted airborne magnetic and electromagnetic surveys of the Paradox and San Luis Valleys in southern Colorado, United States. These airborne geophysical surveys provide high-resolution and spatially comprehensive datasets characterizing the resistivity structure of the shallow subsurface of each survey region, accompanied by magnetic-field information over matching areas. These data were collected to provide insight into the distribution of groundwater brine in the Paradox Valley, the extent of clay aquitards in the San Luis Valley, and to improve our understanding of the geologic framework for both regions. This report describes these contracted surveys and releases digital data supplied under contract to the USGS.

Sentient Structures: Optimising Sensor Layouts for Direct Measurement of Discrete Variables

DTIC Science & Technology

2008-11-01

1 Sentient Structures Optimising Sensor Layouts for Direct Measurement of Discrete Variables Report to US Air Force...TITLE AND SUBTITLE Sentient Structures 5a. CONTRACT NUMBER FA48690714045 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Donald Price...optimal sensor placements is an important requirement for the development of sentient structures. An optimal sensor layout is attained when a limited

Study of skeletal muscle cross-bridge population dynamics by second harmonic generation

NASA Astrophysics Data System (ADS)

Nucciotti, V.; Stringari, C.; Sacconi, L.; Vanzi, F.; Tesi, C.; Pirrodi, N.; Poggesi, C.; Castiglioni, C.; Milani, A.; Linari, M.; Piazzesi, G.; Lombardi, V.; Pavone, F. S.

2007-02-01

The high degree of structural order in skeletal muscle allows imaging of this tissue by Second Harmonic Generation (SHG). Biochemical and colocalization studies have gathered an increasing wealth of clues for the attribution of the molecular origin of the muscle SHG signal to the motor protein myosin. Thus, SHG represents a potentially very powerful tool in the investigation of structural dynamics occurring in muscle during active production of force and/or shortening. A full characterization of the polarization-dependence of the SHG signal represents a very selective information on the orientation of the emitting proteins and their dynamics during contraction, provided that different physiological states of muscle (relaxed, rigor and active) exhibit distinct patterns of SHG polarization dependence. Here polarization data are obtained from single frog muscle fibers at rest and during isometric contraction and interpreted, by means of a model, in terms of an average orientation of the SHG emitters which are structured with a cylindrical symmetry about the fiber axis. The setup is optimized for accurate polarization measurements with SHG, combined with a line scan imaging method allowing acquisition of SHG polarization curves in different physiological states. We demonstrate that muscle fiber displays a measurable variation of the orientation of SHG emitters with the transition from rest to isometric contraction.

Tectonic evolution of the Neoproterozoic Tandilia sedimentary cover, Argentina: New evidence of contraction and extensional events in the southwest Gondwana margin

NASA Astrophysics Data System (ADS)

Hernández, Mariano; Arrouy, María Julia; Scivetti, Nicolás; Franzese, Juan R.; Canalicchio, José M.; Poiré, Daniel G.

2017-11-01

At the northwestern portion of the Tandilia System, a detailed structural analysis on the Precambrian sedimentary units exposed in the quarries of the Olavarría-Sierras Bayas area was carried out. These units exhibit deformational structures of several scales, from centimeters to hundreds of meters. The hundreds of meters scale involves E-W- and NW-SE-trending normal faults and NW-SE- and NE-SW-trending contractional folds. The centimeters to meters scale involves veins, joints, normal faults, shear fractures and stylolites, with a prevailing ∼ E-W to NW-SE trend. All these structures were formed by two major tectonic events. The first was the folding event at ∼580 Ma, with NNE-SSW to NE-SW and NW-SE direction of contraction. The second was the extensional faulting event, given by the widespread NNE-SSW-directed extension event during the Atlantic Ocean opening (Jurassic-Cretaceous). Both major events would have been controlled by the reactivation of basement anisotropies. These major tectonic events controlled the deformation of the Precambrian sedimentary cover of the Tandilia system, leading to an economically important aspect in the mining development of the Olavarría-Sierras Bayas area.

Late Oligocene to present contractional structure in and around the Susitna basin, Alaska—Geophysical evidence and geological implications

USGS Publications Warehouse

Saltus, Richard W.; Stanley, Richard G.; Haeussler, Peter J.; Jones, James V.; Potter, Christopher J.; Lewis, Kristen A.

2016-01-01

The Cenozoic Susitna basin lies within an enigmatic lowland surrounded by the Central Alaska Range, Western Alaska Range (including the Tordrillo Mountains), and Talkeetna Mountains in south-central Alaska. Some previous interpretations show normal faults as the defining structures of the basin (e.g., Kirschner, 1994). However, analysis of new and existing geophysical data shows predominantly (Late Oligocene to present) thrust and reverse fault geometries in the region, as previously proposed by Hackett (1978). A key example is the Beluga Mountain fault where a 50-mGal gravity gradient, caused by the density transition from the igneous bedrock of Beluga Mountain to the >4-km-thick Cenozoic sedimentary section of Susitna basin, spans a horizontal distance of ∼40 km and straddles the topographic front. The location and shape of the gravity gradient preclude a normal fault geometry; instead, it is best explained by a southwest-dipping thrust fault, with its leading edge located several kilometers to the northeast of the mountain front, concealed beneath the shallow glacial and fluvial cover deposits. Similar contractional fault relationships are observed for other basin-bounding and regional faults as well. Contractional structures are consistent with a regional shortening strain field inferred from differential offsets on the Denali and Castle Mountain right-lateral strike-slip fault systems.

The Policy Implications of the Cost Structure of Home Health Agencies

PubMed Central

Mukamel, Dana B; Fortinsky, Richard H; White, Alan; Harrington, Charlene; White, Laura M; Ngo-Metzger, Quyen

2014-01-01

Purpose To examine the cost structure of home health agencies by estimating an empirical cost function for those that are Medicare-certified, ten years following the implementation of prospective payment. Design and Methods 2010 national Medicare cost report data for certified home health agencies were merged with case-mix information from the Outcome and Assessment Information Set (OASIS). We estimated a fully interacted (by tax status) hybrid cost function for 7,064 agencies and calculated marginal costs as percent of total costs for all variables. Results The home health industry is dominated by for-profit agencies, which tend to be newer than the non-profit agencies and to have higher average costs per patient but lower costs per visit. For-profit agencies tend to have smaller scale operations and different cost structures, and are less likely to be affiliated with chains. Our estimates suggest diseconomies of scale, zero marginal cost for contracting with therapy workers, and a positive marginal cost for contracting with nurses, when controlling for quality. Implications Our findings suggest that efficiencies may be achieved by promoting non-profit, smaller agencies, with fewer contract nursing staff. This conclusion should be tested further in future studies that address some of the limitations of our study. PMID:24949224

New Perspectives on Ancient Mars

NASA Technical Reports Server (NTRS)

Solomon, Sean C.; Aharonson, O.; Aurnou, J. M.; Banerdt, W. B.; Carr, M. H.; Dombard, A. J.; Frey, H. V.; Golombek, M. P.; Hauck, S. A., II; Head, J. W., III

2004-01-01

Global data sets returned by the Mars Global Surveyor (MGS), Mars Odyssey, and Mars Express spacecraft and recent analyses of Martian meteorites suggest that most of the major geological events of Martian history occurred within the first billion years of solar system formation. This period was a time of heavy impact bombardment of the inner solar system, a process that strongly overprinted much of the Martian geological record from that time. Geophysical signatures nonetheless remain from that period in the Martian crust, and several geochemical tracers of early events are found in Martian meteorites. Collectively, these observations provide insight into the earliest era in Martian history when the conditions favoring life were best satisfied.

The Impact of Structured Teaching Methods on the Quality of Education in Brazil

ERIC Educational Resources Information Center

Leme, Maria Carolina; Louzano, Paula; Ponczek, Vladimir; Souza, Andre Portela

2012-01-01

This paper estimates the impact of the use of structured methods on the quality of education for students in primary public school in Brazil. Structured methods encompass a range of pedagogical and managerial instruments applied in the educational system. In recent years, several municipalities in the state of Sao Paulo have contracted out private…

Keratinocyte cytoskeletal roles in cell sheet engineering

PubMed Central

2013-01-01

Background There is an increasing need to understand cell-cell interactions for cell and tissue engineering purposes, such as optimizing cell sheet constructs, as well as for examining adhesion defect diseases. For cell-sheet engineering, one major obstacle to sheet function is that cell sheets in suspension are fragile and, over time, will contract. While the role of the cytoskeleton in maintaining the structure and adhesion of cells cultured on a rigid substrate is well-characterized, a systematic examination of the role played by different components of the cytoskeleton in regulating cell sheet contraction and cohesion in the absence of a substrate has been lacking. Results In this study, keratinocytes were cultured until confluent and cell sheets were generated using dispase to remove the influence of the substrate. The effects of disrupting actin, microtubules or intermediate filaments on cell-cell interactions were assessed by measuring cell sheet cohesion and contraction. Keratin intermediate filament disruption caused comparable effects on cell sheet cohesion and contraction, when compared to actin or microtubule disruption. Interfering with actomyosin contraction demonstrated that interfering with cell contraction can also diminish cell cohesion. Conclusions All components of the cytoskeleton are involved in maintaining cell sheet cohesion and contraction, although not to the same extent. These findings demonstrate that substrate-free cell sheet biomechanical properties are dependent on the integrity of the cytoskeleton network. PMID:23442760

Neogene to recent contraction and basin inversion along the Nubia-Iberia boundary in SW Iberia

NASA Astrophysics Data System (ADS)

Ramos, Adrià; Fernández, Oscar; Terrinha, Pedro; Muñoz, Josep Anton

2017-02-01

The SW of Iberia is currently undergoing compression related to the convergence between Nubia and Iberia. Multiple compressive structures, and their related seismic activity, have been documented along the diffuse Nubia-Iberia plate boundary, including the Gorringe bank west of the Gulf of Cadiz, and the Betic-Rif orogen to the east. Despite seismic activity indicating a dominant compressive stress along the Algarve margin in the Gulf of Cadiz, the structures at the origin of this seismicity remain elusive. This paper documents the contractional structures that provide linkage across the Gulf of Cadiz and play a major role in defining the present-day seismicity and bathymetry of this area. The structures described in this paper caused the Neogene inversion of the Jurassic oblique passive margin that formed between the central Atlantic and the Ligurian Tethys. This example of a partially inverted margin provides insights into the factors that condition the inversion of passive margins.

In vitro organogenesis of gut-like structures from mouse embryonic stem cells.

PubMed

Kuwahara, M; Ogaeri, T; Matsuura, R; Kogo, H; Fujimoto, T; Torihashi, S

2004-04-01

Embryonic stem (ES) cells have pluripotency and give rise to many cell types and tissues, including representatives of all three germ layers in the embryo. We have reported previously that mouse ES cells formed contracting gut-like organs from embryoid bodies (EBs). These gut-like structures contracted spontaneously, and had large lumens surrounded by three layers, i.e. epithelium, lamina propria and muscularis. Ganglia were scattered along the periphery, and interstitial cells of Cajal (ICC) were distributed among the smooth muscle cells. In the present study, to determine whether they can be a model of gut organogenesis, we investigated the formation process of the gut-like structures in comparison with embryonic gut development. As a result, we found that the fundamental process of formation in vitro was similar to embryonic gut development in vivo. The result indicates that the gut-like structure is a useful tool not only for developmental study to determine the factors that induce gut organogenesis, but also for studies of enteric neurone and ICC development.

Early Holocene (8.6 ka) rock avalanche deposits, Obernberg valley (Eastern Alps): Landform interpretation and kinematics of rapid mass movement.

PubMed

Ostermann, Marc; Sanders, Diethard; Ivy-Ochs, Susan; Alfimov, Vasily; Rockenschaub, Manfred; Römer, Alexander

2012-10-15

In the Obernberg valley, the Eastern Alps, landforms recently interpreted as moraines are re-interpreted as rock avalanche deposits. The catastrophic slope failure involved an initial rock volume of about 45 million m³, with a runout of 7.2 km over a total vertical distance of 1330 m (fahrböschung 10°). 36 Cl surface-exposure dating of boulders of the avalanche mass indicates an event age of 8.6 ± 0.6 ka. A 14 C age of 7785 ± 190 cal yr BP of a palaeosoil within an alluvial fan downlapping the rock avalanche is consistent with the event age. The distal 2 km of the rock-avalanche deposit is characterized by a highly regular array of transverse ridges that were previously interpreted as terminal moraines of Late-Glacial. 'Jigsaw-puzzle structure' of gravel to boulder-size clasts in the ridges and a matrix of cataclastic gouge indicate a rock avalanche origin. For a wide altitude range the avalanche deposit is preserved, and the event age of mass-wasting precludes both runout over glacial ice and subsequent glacial overprint. The regularly arrayed transverse ridges thus were formed during freezing of the rock avalanche deposits.

The tectonic fabric of the ocean basins

NASA Astrophysics Data System (ADS)

Matthews, Kara J.; Müller, R. Dietmar; Wessel, Paul; Whittaker, Joanne M.

2011-12-01

We present a global community data set of fracture zones (FZs), discordant zones, propagating ridges, V-shaped structures and extinct ridges, digitized from vertical gravity gradient (VGG) maps. We use a new semi-automatic FZ tracking program to test the precision of our hand-digitized traces and find a Mean Absolute Deviation of less than 3.4 km from the raw VGG minima that most clearly delineate each feature, and less than 5.4 km from the FZ location predicted by fitting model profiles to the VGG data that represent the morphology of the individual FZs. These offsets are small considering gravity data only provide an approximation for the underlying basement morphology. We further investigate the origin of non-FZ seafloor fabric by combining published abyssal hill heights computed from gravity anomalies with global half-spreading rates. A residual abyssal hill height grid, with spreading rate effects removed, combined with our interpreted tectonic fabric reveals several types of seafloor fabric distinct from typical abyssal hills. Where discordant zones do not overprint abyssal hill signals, residual abyssal hill height anomalies correspond to seafloor that accreted near mantle thermal anomalies or zones of melt-depletion. Our analysis reveals several areas where residual abyssal hill height anomalies reflect pseudo-faults and extinct ridges associated with ridge propagation and/or microplate formation in the southern Pacific Ocean.

Rhabdovirus accessory genes.

PubMed

Walker, Peter J; Dietzgen, Ralf G; Joubert, D Albert; Blasdell, Kim R

2011-12-01

The Rhabdoviridae is one of the most ecologically diverse families of RNA viruses with members infecting a wide range of organisms including placental mammals, marsupials, birds, reptiles, fish, insects and plants. The availability of complete nucleotide sequences for an increasing number of rhabdoviruses has revealed that their ecological diversity is reflected in the diversity and complexity of their genomes. The five canonical rhabdovirus structural protein genes (N, P, M, G and L) that are shared by all rhabdoviruses are overprinted, overlapped and interspersed with a multitude of novel and diverse accessory genes. Although not essential for replication in cell culture, several of these genes have been shown to have roles associated with pathogenesis and apoptosis in animals, and cell-to-cell movement in plants. Others appear to be secreted or have the characteristics of membrane-anchored glycoproteins or viroporins. However, most encode proteins of unknown function that are unrelated to any other known proteins. Understanding the roles of these accessory genes and the strategies by which rhabdoviruses use them to engage, divert and re-direct cellular processes will not only present opportunities to develop new anti-viral therapies but may also reveal aspects of cellar function that have broader significance in biology, agriculture and medicine. Crown Copyright © 2011. Published by Elsevier B.V. All rights reserved.

Numerical model of the transition from continental rifting to oceanization: the case study of the Ligure-Piemontese ocean.

NASA Astrophysics Data System (ADS)

Roda, M.; Marotta, A. M.; Conte, K.; Spalla, M. I.

2015-12-01

The transition from continental rifting to oceanization has been investigated by mean of a 2D thermo-mechanical numerical model in which the formation of oceanic crust by mantle serpentinization, due to the hydration of the uprising peridotite, as been implemented. Model predictions have been compared with natural data related to the Permian-Triassic thinning affecting the continental lithosphere of the Alpine domain, in order to identify which portions of the present Alpine-Apennine system, preserving the imprints of Permian-Triassic high temperature (HT) metamorphism, is compatible, in terms of lithostratigraphy and tectono-metamorphic evolution, with a lithospheric extension preceding the opening of the Ligure-Piemontese oceanic basin. At this purpose age, petrological and structural data from the Alpine and Apennine ophiolite complexes are compared with model predictions from the oceanization stage. Our comparative analysis supports the thesis that the lithospheric extension preceding the opening of the Alpine Tethys did not start on a stable continental lithosphere, but developed by recycling part of the old Variscan collisional suture. The HT Permian-Triassic metamorphic re-equilibration overprints an inherited tectonic and metamorphic setting consequent to the Variscan subduction and collision, making the Alps a key case history to explore mechanisms responsible for the re-activation of orogenic scars.

Tectonic evolution of the Fru\\vska Gora (NW Serbia) and implications for the late stage inversion of the Pannonian Basin

NASA Astrophysics Data System (ADS)

Novčić, Novak; Toljić, Marinko; Stojadinović, Uroš; Matenco, Liviu

2017-04-01

Indentation of Adria microplate during latest Miocene to Quaternary times created contraction and transcurrent movements distributed in the Dinarides Mountains and along its margin with the adjacent Pannonian Basin. Fru\\vska Gora of northern Serbia is one of the few areas along the southern margin of the Pannonian Basin where the kinematic effects of this late-stage inversion can be studied. These mountains are located along the Sava-Vardar Suture Zone as an isolated inselberg surrounded by Neogene deposits of the Pannonian Basin, exposing metamorphic rocks, Mesozoic ophiolites and sediments belonging to the Dinarides units. Our field kinematic study demonstrate that deformation structures are related to several Oligocene - Miocene extensional and latest Miocene - Quaternary contractional deformation events. These events took place during the differential rotational stages experienced by Fru\\vska Gora. This has created a gradual change in strike from N-S to E-W of three successive normal faulting episodes (Oligocene-Early Miocene, Early Miocene and Middle-Late Miocene), subsequently inverted by contractional deformation. This latter deformation took place during the continuous latest Miocene - Quaternary Adria indentation and was accompanied by yet another 40 degrees counter clockwise rotation of the entire Fru\\vska Gora. Almost all resulting contractional structures reactivate the pre-existing Oligocene - Miocene normal faults. This is reflected in the present-day morphology of Fruska Gora that has a large-scale flower-type of structural geometry formed during dextral transpression, as demonstrated by field kinematics and seismic interpretations. This overall geometry is significantly different when compared with other areas situated more westwards in a similar structural position in the Dinariders at their contact with the Pannonian Basin, such as Medvednica Mountains or Sava-Drava transpressional systems. The variation in offsets along the strike of the orogen demonstrate that the indentation into the Pannonian basin significantly decrease eastwards towards Fruska Gora, likely accommodating a large-scale variation in indentation mechanics across and along the Dinarides.

Advanced transportation system studies technical area 2 (TA-2): Heavy lift launch vehicle development. volume 3; Program Cost estimates

NASA Technical Reports Server (NTRS)

McCurry, J. B.

1995-01-01

The purpose of the TA-2 contract was to provide advanced launch vehicle concept definition and analysis to assist NASA in the identification of future launch vehicle requirements. Contracted analysis activities included vehicle sizing and performance analysis, subsystem concept definition, propulsion subsystem definition (foreign and domestic), ground operations and facilities analysis, and life cycle cost estimation. The basic period of performance of the TA-2 contract was from May 1992 through May 1993. No-cost extensions were exercised on the contract from June 1993 through July 1995. This document is part of the final report for the TA-2 contract. The final report consists of three volumes: Volume 1 is the Executive Summary, Volume 2 is Technical Results, and Volume 3 is Program Cost Estimates. The document-at-hand, Volume 3, provides a work breakdown structure dictionary, user's guide for the parametric life cycle cost estimation tool, and final report developed by ECON, Inc., under subcontract to Lockheed Martin on TA-2 for the analysis of heavy lift launch vehicle concepts.

Expected performance of m-solution backtracking

NASA Technical Reports Server (NTRS)

Nicol, D. M.

1986-01-01

This paper derives upper bounds on the expected number of search tree nodes visited during an m-solution backtracking search, a search which terminates after some preselected number m problem solutions are found. The search behavior is assumed to have a general probabilistic structure. The results are stated in terms of node expansion and contraction. A visited search tree node is said to be expanding if the mean number of its children visited by the search exceeds 1 and is contracting otherwise. It is shown that if every node expands, or if every node contracts, then the number of search tree nodes visited by a search has an upper bound which is linear in the depth of the tree, in the mean number of children a node has, and in the number of solutions sought. Also derived are bounds linear in the depth of the tree in some situations where an upper portion of the tree contracts (expands), while the lower portion expands (contracts). While previous analyses of 1-solution backtracking have concluded that the expected performance is always linear in the tree depth, the model allows superlinear expected performance.

Clear-Water Contraction Scour at Selected Bridge Sites in the Black Prairie Belt of the Coastal Plain in Alabama, 2006

USGS Publications Warehouse

Lee, K.G.; Hedgecock, T.S.

2008-01-01

The U.S. Geological Survey, in cooperation with the Alabama Department of Transportation, made observations of clear-water contraction scour at 25 bridge sites in the Black Prairie Belt of the Coastal Plain of Alabama. These bridge sites consisted of 54 hydraulic structures, of which 37 have measurable scour holes. Observed scour depths ranged from 1.4 to 10.4 feet. Theoretical clear-water contraction-scour depths were computed for each bridge and compared with observed scour. This comparison showed that theoretical scour depths, in general, exceeded the observed scour depths by about 475 percent. Variables determined to be important in developing scour in laboratory studies along with several other hydraulic variables were investigated to understand their influence within the Alabama field data. The strongest explanatory variables for clear-water contraction scour were channel-contraction ratio and velocity index. Envelope curves were developed relating both of these explanatory variables to observed scour. These envelope curves provide useful tools for assessing reasonable ranges of scour depth in the Black Prairie Belt of Alabama.

Nurse employment contracts in Chinese hospitals: impact of inequitable benefit structures on nurse and patient satisfaction

PubMed Central

2014-01-01

Purpose Ongoing economic and health system reforms in China have transformed nurse employment in Chinese hospitals. Employment of ‘bianzhi’ nurses, a type of position with state-guaranteed lifetime employment that has been customary since 1949, is decreasing while there is an increase in the contract-based nurse employment with limited job security and reduced benefits. The consequences of inequities between the two types of nurses in terms of wages and job-related benefits are unknown. This study examined current rates of contract-based nurse employment and the effects of the new nurse contract employment strategy on nurse and patient outcomes in Chinese hospitals. Methods This cross-sectional study used geographically representative survey data collected from 2008 to 2010 from 181 hospitals in six provinces, two municipalities, and one autonomous region in China. Logistic regression models were used to estimate the association between contract-based nurse utilization, dissatisfaction among contract-based nurses, nurse intentions to leave their positions, and patient satisfaction, controlling for nurse, patient, and hospital characteristics. Principal Results Hospital-level utilization of contract-based nurses varies greatly from 0 to 91%, with an average of 51%. Contract-based nurses were significantly more dissatisfied with their remuneration and benefits than ‘bianzhi’ nurses who have more job security (P <0.01). Contract-based nurses who were dissatisfied with their salary and benefits were more likely to intend to leave their current positions (P <0.01). Hospitals with high levels of dissatisfaction with salary and benefits among contract-based nurses were rated lower and less likely to be recommended by patients (P < 0.05). Conclusions Our results suggest a high utilization of contract-based nurses in Chinese hospitals, and that the inequities in benefits between contract-based nurses and ‘bianzhi’ nurses may adversely affect both nurse and patient satisfaction in hospitals. Our study provides empirical support for the ‘equal pay for equal work’ policy emphasized by the China Ministry of Health’s recent regulations, and calls for efforts in Chinese hospitals to eliminate the disparities between ‘bianzhi’ and contract-based nurses. PMID:24418223

Characteristics of power spectrum density function of EMG during muscle contraction below 30%MVC.

PubMed

Roman-Liu, Danuta; Konarska, Maria

2009-10-01

The aim of the study was to quantify changes in PSDF frequency bands of the EMG signal and EMG parameters such as MF, MPF and zero crossing, with an increase in the level of muscle contractions in the range from 0.5% to 30% RMS(max) and to determine the frequency bands with the lowest dependency on RMS level so that this could be used in investigating muscle fatigue. Sixteen men, aged from 23 to 33 years old (mean 26.1), who participated in the study performed two force exertion tests. Fragments of EMG which corresponded to the levels of muscle contraction of 0.5%, 1%, 2.5%, 5%, 10%, 15%, 20%, 25%, 30% RMS(max) registered from left and right trapezius pars descendents (TP) and left and right extensor digitorum superficialis (ED) muscles were selected for analysis. The analysis included changes in standard parameters of the EMG signal and changes in PSDF frequency bands, which occurred across muscle contraction levels. To analyze changes in PSDF across the level of muscle contraction, the spectrum was divided into six frequency bandwidths. The analysis of parameters focused on the differences in those parameters between the analyzed muscles, at different levels of muscle contraction. The study revealed that, at muscle contraction levels below 5% RMSmax, contraction level influences standard parameters of the EMG signal and that at such levels of muscle contraction every change in muscle contraction level (recruitment of additional MUs) is reflected in PSDF. The frequency band with the lowest dependency on contraction level was 76-140 Hz for which in both muscles no contraction level effect was detected for contraction levels above 5% RMS(max). The reproducibility of the results was very high, since the observations in of the left and right muscles were almost equal. The other factor, which strongly influences PSDF of the EMG signal, is probably the examined muscle structure (muscle morphology, size, function, subcutaneous layer, cross talk). It seems that low frequency bands up to 25 Hz are especially feasible for type of muscle.

Nurse employment contracts in Chinese hospitals: impact of inequitable benefit structures on nurse and patient satisfaction.

PubMed

Shang, Jingjing; You, Liming; Ma, Chenjuan; Altares, Danielle; Sloane, Douglas M; Aiken, Linda H

2014-01-13

Ongoing economic and health system reforms in China have transformed nurse employment in Chinese hospitals. Employment of 'bianzhi' nurses, a type of position with state-guaranteed lifetime employment that has been customary since 1949, is decreasing while there is an increase in the contract-based nurse employment with limited job security and reduced benefits. The consequences of inequities between the two types of nurses in terms of wages and job-related benefits are unknown. This study examined current rates of contract-based nurse employment and the effects of the new nurse contract employment strategy on nurse and patient outcomes in Chinese hospitals. This cross-sectional study used geographically representative survey data collected from 2008 to 2010 from 181 hospitals in six provinces, two municipalities, and one autonomous region in China. Logistic regression models were used to estimate the association between contract-based nurse utilization, dissatisfaction among contract-based nurses, nurse intentions to leave their positions, and patient satisfaction, controlling for nurse, patient, and hospital characteristics. Hospital-level utilization of contract-based nurses varies greatly from 0 to 91%, with an average of 51%. Contract-based nurses were significantly more dissatisfied with their remuneration and benefits than 'bianzhi' nurses who have more job security (P <0.01). Contract-based nurses who were dissatisfied with their salary and benefits were more likely to intend to leave their current positions (P <0.01). Hospitals with high levels of dissatisfaction with salary and benefits among contract-based nurses were rated lower and less likely to be recommended by patients (P < 0.05). Our results suggest a high utilization of contract-based nurses in Chinese hospitals, and that the inequities in benefits between contract-based nurses and 'bianzhi' nurses may adversely affect both nurse and patient satisfaction in hospitals. Our study provides empirical support for the 'equal pay for equal work' policy emphasized by the China Ministry of Health's recent regulations, and calls for efforts in Chinese hospitals to eliminate the disparities between 'bianzhi' and contract-based nurses.

Neutrophils contribute to muscle injury and impair its resolution after lengthening contractions in mice

PubMed Central

Pizza, Francis X; Peterson, Jennifer M; Baas, Joel H; Koh, Timothy J

2005-01-01

We tested the hypotheses that: (1) neutrophil accumulation after contraction-induced muscle injury is dependent on the β2 integrin CD18, (2) neutrophils contribute to muscle injury and oxidative damage after contraction-induced muscle injury, and (3) neutrophils aid the resolution of contraction-induced muscle injury. These hypotheses were tested by exposing extensor digitorum longus (EDL) muscles of mice deficient in CD18 (CD18−/−; Itgb2tm1Bay) and of wild type mice (C57BL/6) to in situ lengthening contractions and by quantifying markers of muscle inflammation, injury, oxidative damage and regeneration/repair. Neutrophil concentrations were significantly elevated in wild type mice at 6 h and 3 days post-lengthening contractions; however, neutrophils remained at control levels at these time points in CD18−/− mice. These data indicate that CD18 is required for neutrophil accumulation after contraction-induced muscle injury. Histological and functional (isometric force deficit) signs of muscle injury and total carbonyl content, a marker of oxidative damage, were significantly higher in wild type relative to CD18−/− mice 3 days after lengthening contractions. These data show that neutrophils exacerbate contraction-induced muscle injury. After statistically controlling for differences in the force deficit at 3 days, wild type mice also demonstrated a higher force deficit at 7 days, a lower percentage of myofibres expressing embryonic myosin heavy chain at 3 and 7 days, and a smaller cross sectional area of central nucleated myofibres at 14 days relative to CD18−/− mice. These observations suggest that neutrophils impair the restoration of muscle structure and function after injury. In conclusion, neutrophil accumulation after contraction-induced muscle injury is dependent on CD18. Furthermore, neutrophils appear to contribute to muscle injury and impair some of the events associated with the resolution of contraction-induced muscle injury. PMID:15550464

The introduction of the new dental contract in England - a baseline qualitative assessment.

PubMed

Milsom, K M; Threlfall, A; Pine, K; Tickle, M; Blinkhorn, A S; Kearney-Mitchell, P

2008-01-26

To record immediately prior to its inception the views of key stakeholders about the new dental contract introduced in April 2006. Nineteen participants (11 dental practice principals and eight primary care trust dental leads) were interviewed using a semi structured approach to find out their views and opinions about dental practice, the reasons for introducing the new dental contract, its implementation and content of the new dental contract. An analysis based upon the constant comparative method was used to identify the common themes about these topics. Practice principals expressed satisfaction with working under pilot Personal Dental Services schemes but there was a concern among dental leads about a fall in dental activity among some dentists. All participants believed the new contract was introduced for political, financial and management reasons. All participants believed that it was introduced to limit and control the dental budget. Participants felt that implementation of the contract was rushed and there was insufficient negotiation. There were also concerns that the contract had not been tested. Dental practitioners were concerned about the calculation and future administration of the unit of dental activity system, the fixing of the budget and the fairness of the new dental charge scheme. Dental leads were concerned about patient access and retention and recruitment of dentists under the new contract. The study found a number of reasons for unease about the new dental contract; it was not perceived as being necessary, it was implemented at speed with insufficient negotiation and it was seen as being untested. Numerous and varied problems were foreseen, the most important being the retention of dentists within the NHS. Participants felt the contract was introduced for financial, political and managerial reasons rather than improving patient care. The initial high uptake of the new dental contract should not be viewed as indicating a high level of approval of its content.

Prior history of FDI muscle contraction: different effect on MEP amplitude and muscle activity.

PubMed

Talis, V L; Kazennikov, O V; Castellote, J M; Grishin, A A; Ioffe, M E

2014-03-01

Motor evoked potentials (MEPs) in the right first dorsal interosseous (FDI) muscle elicited by transcranial magnetic stimulation of left motor cortex were assessed in ten healthy subjects during maintenance of a fixed FDI contraction level. Subjects maintained an integrated EMG (IEMG) level with visual feedback and reproduced this level by memory afterwards in the following tasks: stationary FDI muscle contraction at the level of 40 ± 5 % of its maximum voluntary contraction (MVC; 40 % task), at the level of 20 ± 5 % MVC (20 % task), and also when 20 % MVC was preceded by either no contraction (0-20 task), by stronger muscle contraction (40-20 task) or by no contraction with a previous strong contraction (40-0-20 task). The results show that the IEMG level was within the prescribed limits when 20 and 40 % stationary tasks were executed with and without visual feedback. In 0-20, 40-20, and 40-0-20 tasks, 20 % IEMG level was precisely controlled in the presence of visual feedback, but without visual feedback the IEMG and force during 20 % IEMG maintenance were significantly higher in the 40-0-20 task than those in 0-20 and 40-20 tasks. That is, without visual feedback, there were significant variations in muscle activity due to different prehistory of contraction. In stationary tasks, MEP amplitudes in 40 % task were higher than in 20 % task. MEPs did not differ significantly during maintenance of the 20 % level in tasks with different prehistory of muscle contraction with and without visual feedback. Thus, in spite of variations in muscle background activity due to different prehistory of contraction MEPs did not vary significantly. This dissociation suggests that the voluntary maintenance of IEMG level is determined not only by cortical mechanisms, as reflected by corticospinal excitability, but also by lower levels of CNS, where afferent signals and influences from other brain structures and spinal cord are convergent.

Neoproterozoic Structural Evolution of the NE-trending 620-540 Ma Ad-Damm Shear Zone, Arabian Shield, Saudi Arabia

NASA Astrophysics Data System (ADS)

Hamimi, Z.; El-Sawy, E. K.; El-Fakharan, A. S.; Shujoon, A.; Matsah, M.; El-Shafei, M.

2012-04-01

Ad-Damm Shear Zone (ASZ) is a NE-trending fault zone separating Jeddah and Asir tectonostratigraphic terranes in the Neoproterozoic juvenile Arabian Shield. ASZ extends ~380 km, with an average width ~2-3 km, from the eye-catching Ruwah Fault Zone in the eastern shield to the Red Sea Coastal plain. It was believed to be one of the conjugate shears of the NW- to NNW- trending sinistral Najd Shear System based on noteworthy dextral shear criteria recorded within the 620 Ma sheared granites of Numan Complex, as well as right-lateral offsets within quartz veins and dikes transected by the shear zone. The present study is an integrated field-based structural analysis and remote sensing. We utilized the ASTER data for lithologic discrimination and automatic structural lineament extraction and analysis of the Neoproterozoic basement lithologies encountered along and within the vicinity of ASZ. Various false color composite images were generated and evaluated for lithological mapping and structural lineaments. The obtained map was analyzed using GIS techniques to interpret the behavior of the existing lineaments and their spatial distribution. Based on the results of the ASTER data, two significant areas; around Bir Ad-Damm and to the south of Wadi Numan, are selected for detailed field investigation. Shear-sense indicators and overprinting relations clearly show a complicated Neoproterozoic history of ASZ, involving at least three deformations: (1) an early attenuated NE-SW sinistral shearing; followed by (2) a SE-directed thrusting phase resulted in the formation SE-verging thrusts and associated thrust-related folds; and (3) late NE-SW intensive dextral transcurrent shearing played a significant role in the creation of mesoscopic shear-zone related folds, particularly in the area near Bir Ad-Damm. Such deformation history demonstrates the same episode of Neoproterozoic deformation exhibited in the NE-trending shear zones in the Arabian-Nubian Shield (ANS).

Paleoclimatic modeling and phylogeography of least killifish, Heterandria formosa: insights into Pleistocene expansion-contraction dynamics and evolutionary history of North American Coastal Plain freshwater biota.

PubMed

Bagley, Justin C; Sandel, Michael; Travis, Joseph; Lozano-Vilano, María de Lourdes; Johnson, Jerald B

2013-10-09

Climatic and sea-level fluctuations throughout the last Pleistocene glacial cycle (~130-0 ka) profoundly influenced present-day distributions and genetic diversity of Northern Hemisphere biotas by forcing range contractions in many species during the glacial advance and allowing expansion following glacial retreat ('expansion-contraction' model). Evidence for such range dynamics and refugia in the unglaciated Gulf-Atlantic Coastal Plain stems largely from terrestrial species, and aquatic species Pleistocene responses remain relatively uninvestigated. Heterandria formosa, a wide-ranging regional endemic, presents an ideal system to test the expansion-contraction model within this biota. By integrating ecological niche modeling and phylogeography, we infer the Pleistocene history of this livebearing fish (Poeciliidae) and test for several predicted distributional and genetic effects of the last glaciation. Paleoclimatic models predicted range contraction to a single southwest Florida peninsula refugium during the Last Glacial Maximum, followed by northward expansion. We inferred spatial-population subdivision into four groups that reflect genetic barriers outside this refuge. Several other features of the genetic data were consistent with predictions derived from an expansion-contraction model: limited intraspecific divergence (e.g. mean mtDNA p-distance = 0.66%); a pattern of mtDNA diversity (mean Hd = 0.934; mean π = 0.007) consistent with rapid, recent population expansion; a lack of mtDNA isolation-by-distance; and clinal variation in allozyme diversity with higher diversity at lower latitudes near the predicted refugium. Statistical tests of mismatch distributions and coalescent simulations of the gene tree lent greater support to a scenario of post-glacial expansion and diversification from a single refugium than to any other model examined (e.g. multiple-refugia scenarios). Congruent results from diverse data indicate H. formosa fits the classic Pleistocene expansion-contraction model, even as the genetic data suggest additional ecological influences on population structure. While evidence for Plio-Pleistocene Gulf Coast vicariance is well described for many freshwater species presently codistributed with H. formosa, this species demography and diversification departs notably from this pattern. Species-specific expansion-contraction dynamics may therefore have figured more prominently in shaping Coastal Plain evolutionary history than previously thought. Our findings bolster growing appreciation for the complexity of phylogeographical structuring within North America's southern refugia, including responses of Coastal Plain freshwater biota to Pleistocene climatic fluctuations.

Contract Design: Risk Management and Evaluation.

PubMed

Mühlbacher, Axel C; Amelung, Volker E; Juhnke, Christin

2018-01-12

Effective risk adjustment is an aspect that is more and more given weight on the background of competitive health insurance systems and vital healthcare systems. The risk structure of the providers plays a vital role in Pay for Performance. A prerequisite for optimal incentive-based service models is a (partial) dependence of the agent's returns on the provider's gain level. Integrated care systems as well as accountable care organisations (ACOs) in the US and similar concepts in other countries are advocated as an effective method of improving the performance of healthcare systems. These systems outline a payment and care delivery model that intends to tie provider reimbursements to predefined quality metrics. By this the total costs of care shall be reduced. Little is known about the contractual design and the main challenges of delegating "accountability" to these new kinds of organisations and/or contracts. The costs of market utilisation are highly relevant for the conception of healthcare contracts; furthermore information asymmetries and contract-specific investments are an obstacle to the efficient operation of ACOs. A comprehensive literature review on methods of designing contracts in Integrated Care was conducted. The research question in this article focuses on how reimbursement strategies, evaluation of measures and methods of risk adjustment can best be integrated in healthcare contracting. Each integrated care contract includes challenges for both payers and providers without having sufficient empirical data on both sides. These challenges are clinical, administrative or financial nature. Risk adjusted contracts ensure that the reimbursement roughly matches the true costs resulting from the morbidity of a population. If reimbursement of care provider corresponds to the actual expenses for an individual/population the problem of risk selection is greatly reduced. The currently used methods of risk adjustment have widely differing model and forecast accuracy. For this reason, it is necessary to clearly regulate the method of risk adjustment in the integrated care contract. The series of three articles on contract design has shown that coordination and motivation problems in designing healthcare contracts cannot be solved at no-costs. Moreover, it became clear, that complete contracts in healthcare are unrealistic and that contracts do always include certain uncertainties. These are based on the risk of random, and no contracting party can control these risks completely. It is also not possible to fully integrate these risks in the contract or to eliminate these risks by the parties.

Effects of Fluid-Structure Interaction on Dynamic Response of Composite Structures: Experimental and Numerical Studies

DTIC Science & Technology

2013-08-01

STRUCTURES: EXPERIMENTAL AND NUMERICAL STUDIES by Young W. Kwon August 1, 2013 Approved for public release; distribution is unlimited Prepared...failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE...AND SUBTITLE Effects of Fluid-Structure Interaction on Dynamic Responses of Composite Structures: Experimental and Numerical Studies 5a. CONTRACT

Periodic organization of the contractile apparatus in smooth muscle revealed by the motion of dense bodies in single cells.

PubMed

Kargacin, G J; Cooke, P H; Abramson, S B; Fay, F S

1989-04-01

To study the organization of the contractile apparatus in smooth muscle and its behavior during shortening, the movement of dense bodies in contracting saponin skinned, isolated cells was analyzed from digital images collected at fixed time intervals. These cells were optically lucent so that punctate structures, identified immunocytochemically as dense bodies, were visible in them with the phase contrast microscope. Methods were adapted and developed to track the bodies and to study their relative motion. Analysis of their tracks or trajectories indicated that the bodies did not move passively as cells shortened and that nearby bodies often had similar patterns of motion. Analysis of the relative motion of the bodies indicated that some bodies were structurally linked to one another or constrained so that the distance between them remained relatively constant during contraction. Such bodies tended to fall into laterally oriented, semirigid groups found at approximately 6-microns intervals along the cell axis. Other dense bodies moved rapidly toward one another axially during contraction. Such bodies were often members of separate semirigid groups. This suggests that the semirigid groups of dense bodies in smooth muscle cells may provide a framework for the attachment of the contractile structures to the cytoskeleton and the cell surface and indicates that smooth muscle may be more well-ordered than previously thought. The methods described here for the analysis of the motion of intracellular structures should be directly applicable to the study of motion in other cell types.

Structural changes of the regulatory proteins bound to the thin filaments in skeletal muscle contraction by X-ray fiber diffraction

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

Sugimoto, Yasunobu; Takezawa, Yasunori; Matsuo, Tatsuhito

2008-04-25

In order to clarify the structural changes related to the regulation mechanism in skeletal muscle contraction, the intensity changes of thin filament-based reflections were investigated by X-ray fiber diffraction. The time course and extent of intensity changes of the first to third order troponin (TN)-associated meridional reflections with a basic repeat of 38.4 nm were different for each of these reflections. The intensity of the first and second thin filament layer lines changed in a reciprocal manner both during initial activation and during the force generation process. The axial spacings of the TN-meridional reflections decreased by {approx}0.1% upon activation relativemore » to the relaxing state and increased by {approx}0.24% in the force generation state, in line with that of the 2.7-nm reflection. Ca{sup 2+}-binding to TN triggered the shortening and a change in the helical symmetry of the thin filaments. Modeling of the structural changes using the intensities of the thin filament-based reflections suggested that the conformation of the globular core domain of TN altered upon activation, undergoing additional conformational changes at the tension plateau. The tail domain of TN moved together with tropomyosin during contraction. The results indicate that the structural changes of regulatory proteins bound to the actin filaments occur in two steps, the first in response to the Ca{sup 2+}-binding and the second induced by actomyosin interaction.« less

Understanding the Global Structure and Evolution of Coronal Mass Ejections in the Solar Wind

NASA Technical Reports Server (NTRS)

Riley, Pete

2004-01-01

This report summarizes the technical progress made during the first six months of the second year of the NASA Living with a Star program contract Understanding the global structure and evolution of coronal mass ejections in the solar wind, between NASA and Science Applications International Corporation, and covers the period November 18, 2003 - May 17,2004. Under this contract SAIC has conducted numerical and data analysis related to fundamental issues concerning the origin, intrinsic properties, global structure, and evolution of coronal mass ejections in the solar wind. During this working period we have focused on a quantitative assessment of 5 flux rope fitting techniques. In the following sections we summarize the main aspects of this work and our proposed investigation plan for the next reporting period. Thus far, our investigation has resulted in 6 refereed scientific publications and we have presented the results at a number of scientific meetings and workshops.

Modern Theories of Pelvic Floor Support : A Topical Review of Modern Studies on Structural and Functional Pelvic Floor Support from Medical Imaging, Computational Modeling, and Electromyographic Perspectives.

PubMed

Peng, Yun; Miller, Brandi D; Boone, Timothy B; Zhang, Yingchun

2018-02-12

Weakened pelvic floor support is believed to be the main cause of various pelvic floor disorders. Modern theories of pelvic floor support stress on the structural and functional integrity of multiple structures and their interplay to maintain normal pelvic floor functions. Connective tissues provide passive pelvic floor support while pelvic floor muscles provide active support through voluntary contraction. Advanced modern medical technologies allow us to comprehensively and thoroughly evaluate the interaction of supporting structures and assess both active and passive support functions. The pathophysiology of various pelvic floor disorders associated with pelvic floor weakness is now under scrutiny from the combination of (1) morphological, (2) dynamic (through computational modeling), and (3) neurophysiological perspectives. This topical review aims to update newly emerged studies assessing pelvic floor support function among these three categories. A literature search was performed with emphasis on (1) medical imaging studies that assess pelvic floor muscle architecture, (2) subject-specific computational modeling studies that address new topics such as modeling muscle contractions, and (3) pelvic floor neurophysiology studies that report novel devices or findings such as high-density surface electromyography techniques. We found that recent computational modeling studies are featured with more realistic soft tissue constitutive models (e.g., active muscle contraction) as well as an increasing interest in simulating surgical interventions (e.g., artificial sphincter). Diffusion tensor imaging provides a useful non-invasive tool to characterize pelvic floor muscles at the microstructural level, which can be potentially used to improve the accuracy of the simulation of muscle contraction. Studies using high-density surface electromyography anal and vaginal probes on large patient cohorts have been recently reported. Influences of vaginal delivery on the distribution of innervation zones of pelvic floor muscles are clarified, providing useful guidance for a better protection of women during delivery. We are now in a period of transition to advanced diagnostic and predictive pelvic floor medicine. Our findings highlight the application of diffusion tensor imaging, computational models with consideration of active pelvic floor muscle contraction, high-density surface electromyography, and their potential integration, as tools to push the boundary of our knowledge in pelvic floor support and better shape current clinical practice.

Role of Fluids in Mechanics of Overthrust Faulting on Titan

NASA Astrophysics Data System (ADS)

Liu, Z.; Radebaugh, J.; Harris, R. A.; Christiansen, E. H.

2013-12-01

Since Cassini has unveiled Titan's surface, its mountains have been commonly associated with contractional tectonism. However, in order to form contractional structures on icy satellites, relatively large stresses are required. The stress required to form contractional structures on Ganymede and Europa is 3-8 times that required for extensional features. Sources of such stresses probably do not exist for most icy satellites. Therefore, a paradox has emerged, wherein no stress source is known that is large enough to produce the contractional structures observed on Titan. A possible solution for the strength paradox is inspired by Hubbert and Rubey (1959) who demonstrated how high fluid pressures reduce the normal stress along a fault plane, therefore significantly reducing frictional resistance to thrusting. Since liquid hydrocarbons have been identified on Titan's surface and may flow in the subsurface, we speculate that fluid pressures associated with liquid hydrocarbons in the subsurface significantly reduce the shear strength of the icy crust and enable contractional structures to form without the requiring large stresses. We use critical wedge theory, which is a mechanism for driving fold-and-thrust belt formation, to test if the slope angles of mountains and crustal conditions with estimated fluid pressures favor the formation of fold-thrust belts on Titan. We evaluated 6 mountain belts with available Cassini SARTopo data using critical wedge calculations. The slopes of 10 traces from valley floors to summits are between 0.4 and 2.5 degrees. We use the measured slopes with varying friction coefficients and fluid pressures to calculate the range of dip angles. The results yielded 840 dip angle values, 689 (82%) of which were in a reasonable range, and consistent with fold belt formation in critical wedge settings. We conclude that crustal liquids have played a key role in Titan's tectonic history. Our results highlight the significance of fluids in planetary lithospheres and have implications for tectonics on all solid bodies that may have fluid in their lithospheres, now or in the past. Reference: Hubbert, M. K. & Rubey, W. W. Role of fluid pressure in mechanics of overthrust faulting I. Mechanics of fluid-filled porous solids and its application to overthrust faulting. Geol. Soc. Am. Bull. 70, 2, 115-166 (1959).

Adverse effects of 4-tert-octylphenol on the production of oxytocin and hCG in pregnant rats

PubMed Central

Kim, Jun; Kang, Eun-Jin; Park, Mee-Na; Lee, Jae-Eon; Hong, So-Hye; An, Sung-Min; Kim, Seung-Chul; Hwang, Dae-Youn

2014-01-01

Endocrine-disrupting chemicals (EDCs) are exogenous substances that alter the structure or function of the endocrine system. 4-Tert-octylphenol (OP) is one of the most representative EDCs and has estrogenic effects. In this study, we examined the effects of ethinyl estradiol (EE) and OP on the pituitary gland, placenta, and uterus of pregnant rats. Expression levels of human chorionic gonadotropin (hCG), oxytocin (OT), and contraction-associated proteins (CAPs) were determined, and uterine contractile activity was measured by uterine contraction assay. EE and OP both increased mRNA expression of OT and hCG in the pituitary gland but not the placenta. Since OT and hCG control uterine contraction, we next examined CAP expression in the uterus. Expression of 15-hydroxyprostaglandin-dehydrogenase (PGDH) was upregulated by OP, whereas expression of other CAPs was unaffected. To clarify the effect of OP on uterine contraction in pregnant rats, uterine contraction assay was performed. The 17β-Estradiol (E2) did not affect contraction of primary uterine cells harvested from pregnant rats in a 3D collagen gel model. However, OP showed different effects from E2 by significantly reducing contraction activity. In summary, we demonstrated that OP interferes with regulation of OT and hCG in the pituitary gland as well as PGDH in the uterus, thereby reducing uterine contraction activity. This result differs from the action of endogenous E2. Collectively, these findings suggest that exposure to EDCs such as OP during pregnancycan reduce uterine contractile ability, which may result in contraction-associated adverse effects such as metratonia, bradytocia, and uterine leiomyomata. PMID:25324873

In vitro models of tail contraction and cytoplasmic streaming in amoeboid cells.

PubMed

Janson, L W; Taylor, D L

1993-10-01

We have developed a reconstituted gel-sol and contractile model system that mimics the structure and dynamics found at the ectoplasm/endoplasm interface in the tails of many amoeboid cells. We tested the role of gel-sol transformations of the actin-based cytoskeleton in the regulation of contraction and in the generation of endoplasm from ectoplasm. In a model system with fully phosphorylated myosin II, we demonstrated that either decreasing the actin filament length distribution or decreasing the extent of actin filament cross-linking initiated both a weakening of the gel strength and contraction. However, streaming of the solated gel components occurred only under conditions where the length distribution of actin was decreased, causing a self-destruct process of continued solation and contraction of the gel. These results offer significant support that gel strength plays an important role in the regulation of actin/myosin II-based contractions of the tail cortex in many amoeboid cells as defined by the solation-contraction coupling hypothesis (Taylor, D. L., and M. Fechheimer. 1982. Phil. Trans. Soc. Lond. B. 299:185-197). The competing processes of solation and contraction of the gel would appear to be mutually exclusive. However, it is the temporal-spatial balance of the rate and extent of two stages of solation, coupled to contraction, that can explain the conversion of gelled ectoplasm in the tail to a solated endoplasm within the same small volume, generation of a force for the retraction of tails, maintenance of cell polarity, and creation of a positive hydrostatic pressure to push against the newly formed endoplasm. The mechanism of solation-contraction of cortical cytoplasm may be a general component of the normal movement of a variety of amoeboid cells and may also be a component of other contractile events such as cytokinesis.

Age-related differences in twitch properties and muscle activation of the first dorsal interosseous.

PubMed

Miller, Jonathan D; Herda, Trent J; Trevino, Michael A; Sterczala, Adam J; Ciccone, Anthony B; Nicoll, Justin X

2017-06-01

To examine twitch force potentiation and twitch contraction duration, as well as electromyographic amplitude (EMG RMS ) and motor unit mean firing rates (MFR) at targeted forces between young and old individuals in the first dorsal interosseous (FDI). Ultrasonography was used to assess muscle quality. Twenty-two young (YG) (age=22.6±2.7years) and 14 older (OD) (age=62.1±4.7years) individuals completed conditioning contractions at 10% and 50% maximal voluntary contraction, (MVC) during which EMG RMS and MFRs were assessed. Evoked twitches preceded and followed the conditioning contractions. Ultrasound images were taken to quantify muscle quality (cross-sectional area [CSA] and echo intensity [EI]). No differences were found between young and old for CSA, pre-conditioning contraction twitch force, or MFRs (P>0.05). However, OD individuals exhibited greater EI and contraction duration (P<0.05), and EMG RMS (YG=35.4±8.7%, OD=43.4±13.2%; P=0.034). Twitch force potentiation was lower for OD (0.311±0.15N) than YG (0.619±0.26N) from pre- to post-50% conditioning contraction (P<0.001). Lower levels of potentiation with elongated contraction durations likely contributed to greater muscle activation during the conditioning contractions in the OD rather than altered MFRs. Ultrasonography suggested age-related changes in muscle structure contributed to altered contractile properties in the OD. Greater muscle activation requirements can have negative implications on fatigue resistance at low to moderate intensities in older individuals. Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

Polymerization contraction stress in light-cured compomer restorative materials.

PubMed

Chen, H Y; Manhart, J; Kunzelmann, K-H; Hickel, R

2003-11-01

The magnitude and kinetics of polymerization contraction stress build-up may be potential predictors of bond failure of adhesive restorations. The present study determined these properties of seven commercial compomers (Dyract, Dyract AP, F2000 Rasant, Hytac, Compoglass F, Luxat, Glasiosite). Polymerization shrinkage was generated by 40 s light curing the test materials (800 mW/cm2). The contraction force induced was recorded for 300 s at room temperature (23-24 degrees C) by means of a Stress-Strain-Analyzer (C factor=0.33). Maximum contraction stress (MPa), coefficient of near linear fit of contraction force/time (gradient) and relative force rate (%/s) of each material were compared with that of two hybrid composites (Tetric Ceram, Prodigy). The statistical analysis was conducted by ANOVA (alpha=0.05) and post hoc Tukey's test. No statistically significant differences in the maximum stress between Glasiosite (2.27+/-0.06 MPa), Hytac (2.31+/-0.07 MPa) and Tetric Ceram (2.21+/-0.11 MPa), and between Compoglass F (2.60+/-0.18 MPa) and Prodigy (2.70+/-0.06 MPa) were found. The contraction stress of F2000 Rasant (3.41+/-0.09 MPa) and Luxat (3.33+/-0.08 MPa) were significantly highest, whilst Dyract exhibited the significantly lowest shrinkage stress (1.27+/-0.08 MPa) among the tested materials. High contraction stress, early start of stress build-up and rapid contraction force development may lead to failure of bond to tooth structure. This study suggested that the contraction stress and kinetic behavior of compomers are generally similar to those of hybrid composites in a dry condition. Dyract might be superior in maintaining the bond with cavity walls compared to conventional hybrid composites in view of its low shrinkage stress.

Simulator Training Requirements and Effectiveness Study (STRES). Part 1. Abstract Bibliography

DTIC Science & Technology

1981-01-01

august 1977 tnrougn January 19dU. The work was performed by a team made up of Canyon Research Group, Inc; Seville Research Corporation; and United...Dr. Thomas Eggemeier. A tri-service STRES Advisory Team participated in guiding and monitoring the work performed during this contract to assure its...8217 STRUCTURE OF THE STRES PROGRAM The primary objectives of STRES, as described in the contract Statement of Work for the present efforts, are to define

Impact of Continuous Competition on Operations and Support Costs

DTIC Science & Technology

2011-05-01

transaction costs High transaction costs Figure 6: Perfectly Competitive Market and Defense Market Structures   Source: (Katz & Rosen , 1998) Monopoly...Source: (Katz & Rosen , 1998) Although the purpose of a contract is to set firm obligations between buyer and seller, many of the DoD’s contracts...Italy, Denmark, The Netherlands, Norway, and Turkey (Gertler, 2010; “Israel’s Barak Approves,” 2010). Many of these allies are interested in

Compensation, Culture and Contracts: The Realities of the DoD’s Blended Workforce

DTIC Science & Technology

2010-05-01

structure, based on customer satisfaction , business development, collateral duties, and participation in morale- building activities. On the government...and customer satisfaction . “One time, an employee bargained for a 30% pay increase. He was working on a cost-plus contract. There’s no way I...and manageable workloads.” Certainly, job satisfaction can be found outside of the DoD as well. One industry manager reminisced, “I’ve held jobs

Past and future demographic dynamics of alpine species: limited genetic consequences despite dramatic range contraction in a plant from the Spanish Sierra Nevada.

PubMed

Blanco-Pastor, J L; Fernández-Mazuecos, M; Vargas, P

2013-08-01

Anthropogenic global climate change is expected to cause severe range contractions among alpine plants. Alpine areas in the Mediterranean region are of special concern because of the high abundance of endemic species with narrow ranges. This study combined species distribution models, population structure analyses and Bayesian skyline plots to trace the past and future distribution and diversity of Linaria glacialis, an endangered narrow endemic species that inhabits summits of Sierra Nevada (Spain). The results showed that: (i) the habitat of this alpine-Mediterranean species in Sierra Nevada suffered little changes during glacial and interglacial stages of late Quaternary; (ii) climatic oscillations in the last millennium (Medieval Warm Period and Little Ice Age) moderately affected the demographic trends of L. glacialis; (iii) future warming conditions will cause severe range contractions; and (iv) genetic diversity will not diminish at the same pace as the distribution range. As a consequence of the low population structure of this species, genetic impoverishment in the alpine zones of Sierra Nevada should be limited during range contraction. We conclude that maintenance of large effective population sizes via high mutation rates and high levels of gene flow may promote the resilience of alpine plant species when confronted with global warming. © 2013 John Wiley & Sons Ltd.

Can conservation contracts co-exist with change? Payment for ecosystem services in the context of adaptive decision-making and sustainability.

PubMed

Hayes, Tanya; Murtinho, Felipe; Cárdenas Camacho, Luis Mario; Crespo, Patricio; McHugh, Sarah; Salmerón, David

2015-01-01

This paper considers the ability of payment for ecosystem services (PES) programs to operate in the context of dynamic and complex social-ecological systems. Drawing on the experiences of two different PES programs in Latin America, we examine how PES institutions fit with the tenets of adaptive decision-making for sustainable resource management. We identify how the program goals and the connection to the market influence the incentive structure, information gathering, learning and feedback processes, and the structure of decision-making rights, specifically the ability to make and modify resource-use rules. Although limited in their generalizability, findings from the two case studies suggest a tension between the contractual model of PES and adaptive decision-making in natural resource systems. PES programs are not inherently decentralized, flexible management tools, as PES contracts tend to restrict decision-making rights and offer minimal flexibility mechanisms to change resource-use practices over the duration of the contract period. Furthermore, PES design and flexibility is heavily dependent on the goals and mission of the buyer and the respective market. If PES is to facilitate sustainable resource management, greater attention is needed to assess how the institutional design of the PES contracts influence the motivation and capacity of participants and program officers alike to adaptively manage the respective resource systems.

Can Conservation Contracts Co-exist with Change? Payment for Ecosystem Services in the Context of Adaptive Decision-Making and Sustainability

NASA Astrophysics Data System (ADS)

Hayes, Tanya; Murtinho, Felipe; Cárdenas Camacho, Luis Mario; Crespo, Patricio; McHugh, Sarah; Salmerón, David

2015-01-01

This paper considers the ability of payment for ecosystem services (PES) programs to operate in the context of dynamic and complex social-ecological systems. Drawing on the experiences of two different PES programs in Latin America, we examine how PES institutions fit with the tenets of adaptive decision-making for sustainable resource management. We identify how the program goals and the connection to the market influence the incentive structure, information gathering, learning and feedback processes, and the structure of decision-making rights, specifically the ability to make and modify resource-use rules. Although limited in their generalizability, findings from the two case studies suggest a tension between the contractual model of PES and adaptive decision-making in natural resource systems. PES programs are not inherently decentralized, flexible management tools, as PES contracts tend to restrict decision-making rights and offer minimal flexibility mechanisms to change resource-use practices over the duration of the contract period. Furthermore, PES design and flexibility is heavily dependent on the goals and mission of the buyer and the respective market. If PES is to facilitate sustainable resource management, greater attention is needed to assess how the institutional design of the PES contracts influence the motivation and capacity of participants and program officers alike to adaptively manage the respective resource systems.

Cost Avoidance vs. Utility Bill Accounting - Explaining theDiscrepancy Between Guaranteed Savings in ESPC Projects and UtilityBills

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

Kumar, S.; Sartor, D.

2005-08-15

Federal agencies often ask if Energy Savings PerformanceContracts (ESPCs) result in the energy and cost savings projected duringthe project development phase. After investing in ESPCs, federal agenciesexpect a reduction in the total energy use and energy cost at the agencylevel. Such questions about the program are common when implementing anESPC project. But is this a fair or accurate perception? Moreimportantly, should the federal agencies evaluate the success or failureof ESPCs by comparing the utility costs before and after projectimplementation?In fact, ESPC contracts employ measurement andverification (M&V) protocols to measure and ensure kilowatt-hour orBTU savings at the project level. In mostmore » cases, the translation toenergy cost savings is not based on actual utility rate structure, but acontracted utility rate that takes the existing utility rate at the timethe contract is signed with a clause to escalate the utility rate by afixed percentage for the duration of the contract. Reporting mechanisms,which advertise these savings in dollars, may imply an impact to budgetsat a much higher level depending on actual utility rate structure. FEMPhas prepared the following analysis to explain why the utility billreduction may not materialize, demonstrate its larger implication onagency s energy reduction goals, and advocate setting the rightexpectations at the outset to preempt the often asked question why I amnot seeing the savings in my utility bill?« less

New Insight into the Role of Tectonics versus Gravitational Deformation in Development of Surface Ruptures along the Ragged Mountain Fault, Katalla, Alaska USA: Applications of High-Resolution Three-Dimensional Terrain Models

NASA Astrophysics Data System (ADS)

Heinlein, S. N.; Pavlis, T. L.; Bruhn, R. L.; McCalpin, J. P.

2017-12-01

This study evaluates a surface structure using 3D visualization of LiDAR and aerial photography then analyzes these datasets using structure mapping techniques. Results provide new insight into the role of tectonics versus gravitational deformation. The study area is located in southern Alaska in the western edge of the St. Elias Orogen where the Yakutat microplate is colliding into Alaska. Computer applications were used to produce 3D terrain models to create a kinematic assessment of the Ragged Mountain fault which trends along the length of the east flank of Ragged Mountain. The area contains geomorphic and structural features which are utilize to determine the type of displacement on the fault. Previous studies described the Ragged Mountain fault as a very shallow (8°), west-dipping thrust fault that reactivated in the Late Holocene by westward-directed gravity sliding and inferred at least 180 m of normal slip, in a direction opposite to the (relative) eastward thrust transport of the structure inferred from stratigraphic juxtaposition. More recently this gravity sliding hypothesis has been questioned and this study evaluates one of these alternative hypotheses; that uphill facing normal fault-scarps along the Ragged Mountain fault trace represent extension above a buried ramp in a thrust and is evaluated with a fault-parallel flow model of hanging-wall folding and extension. Profiles across the scarp trace were used to illustrate the curvature of the topographic surfaces adjacent to the scarps system and evaluate their origin. This simple kinematic model tests the hypothesis that extensional fault scarps at the surface are produced by flexure above a deeper ramp in a largely blind thrust system. The data in the context of this model implies that the extensional scarp structures previously examined represent a combination of erosionally modified features overprinted by flexural extension above a thrust system. Analyses of scarp heights along the structure are combined with the model to suggest a decrease in Holocene slip from south to north along the Ragged Mountain fault from 11.3 m to 0.2 m, respectively.

Poorly Understood Aspects of Striated Muscle Contraction

PubMed Central

Månsson, Alf

2015-01-01

Muscle contraction results from cyclic interactions between the contractile proteins myosin and actin, driven by the turnover of adenosine triphosphate (ATP). Despite intense studies, several molecular events in the contraction process are poorly understood, including the relationship between force-generation and phosphate-release in the ATP-turnover. Different aspects of the force-generating transition are reflected in the changes in tension development by muscle cells, myofibrils and single molecules upon changes in temperature, altered phosphate concentration, or length perturbations. It has been notoriously difficult to explain all these events within a given theoretical framework and to unequivocally correlate observed events with the atomic structures of the myosin motor. Other incompletely understood issues include the role of the two heads of myosin II and structural changes in the actin filaments as well as the importance of the three-dimensional order. We here review these issues in relation to controversies regarding basic physiological properties of striated muscle. We also briefly consider actomyosin mutation effects in cardiac and skeletal muscle function and the possibility to treat these defects by drugs. PMID:25961006

Poorly understood aspects of striated muscle contraction.

PubMed

Månsson, Alf; Rassier, Dilson; Tsiavaliaris, Georgios

2015-01-01

Muscle contraction results from cyclic interactions between the contractile proteins myosin and actin, driven by the turnover of adenosine triphosphate (ATP). Despite intense studies, several molecular events in the contraction process are poorly understood, including the relationship between force-generation and phosphate-release in the ATP-turnover. Different aspects of the force-generating transition are reflected in the changes in tension development by muscle cells, myofibrils and single molecules upon changes in temperature, altered phosphate concentration, or length perturbations. It has been notoriously difficult to explain all these events within a given theoretical framework and to unequivocally correlate observed events with the atomic structures of the myosin motor. Other incompletely understood issues include the role of the two heads of myosin II and structural changes in the actin filaments as well as the importance of the three-dimensional order. We here review these issues in relation to controversies regarding basic physiological properties of striated muscle. We also briefly consider actomyosin mutation effects in cardiac and skeletal muscle function and the possibility to treat these defects by drugs.

Role of the Z band in the mechanical properties of the heart.

PubMed

Goldstein, M A; Schroeter, J P; Michael, L H

1991-05-01

In striated muscle the mechanism of contraction involves the cooperative movement of contractile and elastic components. This review emphasizes a structural approach that describes the cellular and extracellular components with known anatomical, biochemical, and physical properties that make them candidates for these contractile and elastic components. Classical models of contractile and elastic elements and their underlying assumptions are presented. Mechanical properties of cardiac and skeletal muscle are compared and contrasted and then related to ultrastructure. Information from these approaches leads to the conclusion that the Z band is essential for muscle contraction. Our review of Z band structure shows the Z band at the interface where extracellular components meet the cell surface. The Z band is also the interface from cell surface to myofibril, from extra-myofibrillar to myofibril, and finally from sarcomere to sarcomere. Our studies of Z band in defined physiologic states show that this lattice is an integral part of the contractile elements and can function as an elastic component. The Z band is a complex dynamic lattice uniquely suited to play several roles in muscle contraction.

Reconstructing late Quaternary palaeosol development and landscape connectivity from combined soil magnetic, geochemical and micromorphological analyses: insights from the Wilgerbosch River, Great Karoo, South Africa.

NASA Astrophysics Data System (ADS)

Oldknow, Chris; Hooke, Janet; Oldfield, Frank

2017-04-01

The characteristics, spatial and temporal patterns and drivers of Quaternary climate change across South Africa remain contentious principally due to the paucity of dated proxy records. River and fan terrace palaeosols may offer an important addition to analysis of spatially pervasive geomorphological landforms (palaeolake shorelines, terraces, dunes) conventionally used to reconstruct patterns of palaeoenvironmental change. In the Great Karoo, alluvial and colluvial exposures in the Wilgerbosch River and several of its tributaries have revealed up to five late Quaternary terraces of varying thickness, extent and pedogenic overprinting which may be of palaeoenvironmental significance. A combination of geochronology (OSL and radiocarbon), soil micromorphology, geochemistry (XRF, XRD) and soil magnetic proxies on both bulk (0-63 μm) and particle size extracts (0-4 and 32-63 μm) from major terrace palaeosols was used in order to establish: 1) changing sediment fluxes and pathways; 2) the characteristics and drivers of palaeosol formation; and 3) evaluate the suitability of these terrace palaeosols as indicators of palaeoenvironmental change. The results are used to test a conceptual model of landscape connectivity. Colluvial (slopewash, head deposits) sedimentation on the valley floors occurred around the time of the LGM due to enhanced regolith production through physical weathering. Soils overprinting these deposits (T1) are goethite-rich attesting to reducing conditions. Incision into T1 resulted in an extensive channel network forming. High concentrations of mafic minerals (Fe, Cr, Ca, Ti) and enhanced ferrimagnetism (XLF > 80) in the 32-63 μm fraction indicated connectivity with slope colluvium proximal to weathering dolerite tors. Fluvial aggradation (T2) occurred as a complex response to this phase of connectivity and terminated in the Late Glacial period (around 17±2.5 ka). The development of a rhizogenic calcrete overprinting T2 indicated an elevated water table and wetlands on the valley floors. Inset clay coatings and calcite hypocoatings attest to fluctuating groundwater levels. The calcrete acted to blanket T1 and T2 reducing extent of connectivity in subsequent phases of terrace development. Sediment in inset fills (T3-4) exhibited diminished primary mineral concentrations and ferrimagnetism (XLF = 20-60) due to recycling of earlier deposits (T1/T2), disconnectivity with 1st order tributaries and episodic gleying and dissolution of organic matter due to fluctuating groundwater level. The terrace palaeosols in the Wilgerbosch catchment are therefore polygenetic reflecting both changing sources of sediment (slope or channel) and multiple phases of soil development under varied palaeohydrological conditions. Caution is therefore urged attempting to relate conventional magnetic (XLF, XARM, XFD) and geochemical (CIA, CIW) metrics of pedogenesis in morphologically similar catchments to palaeoclimatic records. The approach taken in this study is presently useful for reconstructing extent of connectivity between landscape components.

Combining High Resolution InSAR and infrared photogrammetry for studying dome degassing and densification mechanisms at Volcán de Colima, Mexico

NASA Astrophysics Data System (ADS)

Salzer, Jacqueline T.; Milillo, Pietro; Varley, Nick; Perissin, Daniele; Pantaleo, Michele; Walter, Thomas R.

2017-04-01

Active volcanoes often display cyclic behaviour with alternating quiescent and eruptive periods. Continuously monitoring volcanic processes such as deformation, seismicity and degassing, irrespective of their current status, is crucial for understanding the parameters governing the fluid transport within the edifice and the transitions between different regimes. However, mapping the deformation and details of fluid escape at the summit of steep sloped volcanoes and integrating these with other types of data is challenging. Here we present for the first time the near-3D surface deformation field derived from high resolution radar interferometry (InSAR) acquired by the satellite TerraSAR-X at a degassing volcano dome and interpret the results in combination with overflight infrared and topographic data. We find that the results strongly differ depending on the chosen InSAR time series method, which potentially overprints the true physical complexities of small scale, shallow deformation processes. We present a new method for accurate mapping of heterogeneities in the dome deformation, and comparison to the topography and precisely located surface temperature anomalies. The identified deformation is dominated by strong but highly localized subsidence of the summit dome. Our results highlight the competing effects of the topography, permeability and shallow volcanic structures controlling the degassing pathways. On small spatial scales compaction sufficiently reduced the dome permeability to redirect the fluid flow. High resolution InSAR monitoring of volcanic domes thus provides valuable data for constraining models of their internal structure, degassing pathways and densification processes.

Einstein and Einstein A: A Study in Crater Morphology

NASA Image and Video Library

2017-12-08

NASA image release May 14, 2010 Einstein and Einstein A: A Study in Crater Morphology Located on the western limb of the Moon, Einstein and Einstein A craters (16.3oN, 271.3oE ) are only visible to Earth-based observers during certain lunar lighting and orientation conditions. Einstein A is younger than Einstein, as indicated by the fact that it lies squarely in the middle of the floor of Einstein. When viewed in topographic data, these two craters reveal much about the relative age and shape of an impact crater. To understand further, let's first take a look at Einstein. Einstein is a fairly large crater that spans 198 km across. A crater's size alone however cannot reveal much about age. ÊEinstein's relative age can be determined by examining the frequency and distribution of impact craters overprinted on its rim and floor. Younger craters have had fewer impacts, which enables them to retain their original morphology. Einstein A reveals most of its original structure, including a raised rim and ejecta blanket, and is therefore a relatively young crater as compared to Einstein, whose original structure has been somewhat degraded over time by smaller impacts. The Einstein craters were named after famed physicist, philosopher, and scientist Albert Einstein (1879-1955). To learn more go to: www.nasa.gov/mission_pages/LRO/multimedia/lroimages/lola-... NASA Goddard Space Flight Center is home to the nation's largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

Hydrodynamic Hull Damping (Phase 1)

DTIC Science & Technology

1987-06-01

Administration Mr. Alexander Malakhoff Mr. Thomas W. Allen Director, Structural Integrity Engineering Officer (N7) Subgroup ( SEA 55Y) MR" Sealift Command...Shipping U. S. Coast Guard CONTRACTING OFFICER TECHNICAL REPRESENTATIVES Mr. William J. Siekierka Mr. Greg D. Woods SEA 55Y3 SEA 55Y3 Naval Sea Systems...Command Naval Sea Systems Command SHIP STRUCTURE SUBCOMMITTEE The SHIP STRUCTURE SUBCOMMITTEE acts for the Ship Structure Committee on technical matters

Analysis of structural dynamic data from Skylab. Volume 1: Technical discussion

NASA Technical Reports Server (NTRS)

Demchak, L.; Harcrow, H.

1976-01-01

A compendium of Skylab structural dynamics analytical and test programs is presented. These programs are assessed to identify lessons learned from the structural dynamic prediction effort and to provide guidelines for future analysts and program managers of complex spacecraft systems. It is a synopsis of the structural dynamic effort performed under the Skylab Integration contract and specifically covers the development, utilization, and correlation of Skylab Dynamic Orbital Models.

Advanced Technology Composite Fuselage - Repair and Damage Assessment Supporting Maintenance

NASA Technical Reports Server (NTRS)

Flynn, B. W.; Bodine, J. B.; Dopker, B.; Finn, S. R.; Griess, K. H.; Hanson, C. T.; Harris, C. G.; Nelson, K. M.; Walker, T. H.; Kennedy, T. C.;

Application of Contraction Mappings to the Control of Nonlinear Systems. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Killingsworth, W. R., Jr.

1972-01-01

The theoretical and applied aspects of successive approximation techniques are considered for the determination of controls for nonlinear dynamical systems. Particular emphasis is placed upon the methods of contraction mappings and modified contraction mappings. It is shown that application of the Pontryagin principle to the optimal nonlinear regulator problem results in necessary conditions for optimality in the form of a two point boundary value problem (TPBVP). The TPBVP is represented by an operator equation and functional analytic results on the iterative solution of operator equations are applied. The general convergence theorems are translated and applied to those operators arising from the optimal regulation of nonlinear systems. It is shown that simply structured matrices and similarity transformations may be used to facilitate the calculation of the matrix Green functions and the evaluation of the convergence criteria. A controllability theory based on the integral representation of TPBVP's, the implicit function theorem, and contraction mappings is developed for nonlinear dynamical systems. Contraction mappings are theoretically and practically applied to a nonlinear control problem with bounded input control and the Lipschitz norm is used to prove convergence for the nondifferentiable operator. A dynamic model representing community drug usage is developed and the contraction mappings method is used to study the optimal regulation of the nonlinear system.

Multi-Physics MRI-Based Two-Layer Fluid-Structure Interaction Anisotropic Models of Human Right and Left Ventricles with Different Patch Materials: Cardiac Function Assessment and Mechanical Stress Analysis

PubMed Central

Tang, Dalin; Yang, Chun; Geva, Tal; Gaudette, Glenn; del Nido, Pedro J.

2011-01-01

Multi-physics right and left ventricle (RV/LV) fluid-structure interaction (FSI) models were introduced to perform mechanical stress analysis and evaluate the effect of patch materials on RV function. The FSI models included three different patch materials (Dacron scaffold, treated pericardium, and contracting myocardium), two-layer construction, fiber orientation, and active anisotropic material properties. The models were constructed based on cardiac magnetic resonance (CMR) images acquired from a patient with severe RV dilatation and solved by ADINA. Our results indicate that the patch model with contracting myocardium leads to decreased stress level in the patch area, improved RV function and patch area contractility. PMID:21765559

The Structure and Dynamics of the Solar Corona and Inner Heliosphere

NASA Technical Reports Server (NTRS)

Mikic, Zoran

2002-01-01

This report covers technical progress during the second quarter of the first year of NASA Sun-Earth Connections Theory Program (SECTP) contract 'The Structure and Dynamics of the Solar Corona and Inner Heliosphere,' NAS5-99188, between NASA and Science Applications International Corporation. and covers the period November 16, 1999 to February 15, 2000. Under this contract SAIC and the University of California, Irvine (UCI) have conducted research into theoretical modeling of active regions, the solar corona, and the inner heliosphere, using the MHD (magnetohydrodynamic) model. The topics studied include: the effect of emerging flux on the stability of helmet streamers, coronal loops and streamers, the solar magnetic field, the solar wind, and open magnetic field lines.

Pashtun Social Structure: Cultural Perceptions and Segmentary Lineage Organization

DTIC Science & Technology

2011-08-03

SOCIAL STRUCTURE: CULTURAL PERCEPTIONS...funded  by  the  Office  of  Naval   Research,  Human   Social  Cultural  Behavioral  Program,  under  Contract   Number...N00014-­‐09-­‐C-­‐0570  to  MacGregor  Bates,  Inc.   PASHTUN SOCIAL STRUCTURE: CULTURAL PERCEPTIONS AND

Service contract with periodic preventive maintenance for a dump truck sold with a two-dimensional warranty

NASA Astrophysics Data System (ADS)

Nasrum, A.; Pasaribu, U. S.; Husniah, H.

2016-02-01

This paper deals with maintenance service contract for a dump truck sold with a two-dimensional warranties. We consider a situation where an agent offers two maintenance contract options and the owner of the equipment has to select the optimal option either the OEM carried out all repairs and preventive maintenance activities (option one) or the OEM only carries out failure while the costumer undertakes preventive maintenance action in-house (option two). As the number of preventive maintenance and corrective maintenance that occurs in the area of servicing contracts is very influential in determining the value of the contract, we have to determine the optimal time between preventive maintenance that can minimize the cost of repair in the contract area. Moreover, we also study the maintenance service contract considering reduction of the intensity function after preventive maintenance from both the owner and OEM point of views. In this paper, we use a Weibull intensity function to consider a product with increasing failure intensity. We use a non-cooperative game formulation to determine the optimal price structure (i.e., the contract price and repair cost) for the OEM and the owner. A numerical example derived from the model has shown that if the owner choose option one then the owner obtain a higher profit compared with the profit resulted from option two. The result agree with earlier work which uses the accelerated failure time (AFT) for the failure modeling, while here we model the failure of the dump truck without the use of the AFT.

Integrin receptor involvement in actin cable formation in an in vitro model of events associated with wound contraction.

PubMed

Stephens, P; Genever, P G; Wood, E J; Raxworthy, M J

1997-01-01

Actin cables have been reported to act in vivo as contractile 'purse strings' capable of closing embryonic wounds through generation of circumferential tension. Furthermore, their involvement in wounds within in vitro model systems suggests that actin cable contraction may be an important mechanism involved in the process of wound closure. The aim of this study therefore, was to investigate the appearance of actin cables in a contracting fibroblast populated collagen lattice, an in vitro model of events associated with wound contraction. Utilising this in vitro model, the time-course of actin cable production was investigated and the involvement of integrin receptors analysed using immunofluorescent labelling techniques. Over a period of hours distinct cellular cable-like structures developed at the edges of collagen lattices coinciding with the onset of contraction. Cellular organisation within the cable was evident as was polymerisation of actin microfilaments into elongated stress fibres forming a continuous cell-cell 'actin cable' around the circumference of the lattice. Immunolocalisation demonstrated that integrin receptor subunits beta 1 and alpha 2 but not alpha 5 were involved in apparent intimate cell-cell contact between juxtaposed fibroblasts within this actin cable. This study demonstrates the involvement of integrin receptors in actin cable formation within collagen lattice systems undergoing reorganisation. Such integrin involvement may enable participating cells to respond to the tensional status of their surrounding environment and via cell-cell communication, to permit a co-ordinated contraction of the cable. It is concluded that integrin receptor involvement in active actin cable contraction may be involved in the process of wound contraction.

A bio-inspired, active morphing skin for camber morphing structures

NASA Astrophysics Data System (ADS)

Feng, Ning; Liu, Liwu; Liu, Yanju; Leng, Jinson

2015-03-01

In this study, one kind of developed morphing skin embedded with pneumatic muscle fibers (PMFs) was manufactured and was employed for camber morphing structures. The output force and contraction of PMF as well as the morphing skin were experimentally characterized at a series of discrete actuator pressures varying from 0.15 to 0.35 MPa. The active morphing skin test results show that the output force is 73.59 N and the contraction is 0.097 (9.7%) at 0.35 MPa. Due to these properties, this active morphing skin could be easily used for the morphing structures. Then the proper airfoil profile was chosen to manufacture the adaptive airfoil in this study. The chord-wise bending airfoil structure was achieved by employing this kind of active morphing skin. Finally the deformed shapes of this chord-wise bending airfoil structure were obtained by 3-dimensions scanning measurement. Meanwhile the camber morphing structures were analyzed through the finite element method (FEM) and the deformed shapes of the upper surface skins were obtained. The experimental result and FEM analysis result of deformed shapes of the upper surface skins were compared in this paper.

Rock Magnetism: Successes and Mysteries

NASA Astrophysics Data System (ADS)

Dunlop, D. J.

2011-12-01

Louis Néel once proposed making ships "invisible" (i.e., magnetically undetectable) by giving them a permanent or remanent magnetism that would cancel the signal induced by the Earth's magnetic field. Like much of rock magnetism, this borders on the magical. Rocks possess a magnetic memory that verges on the phenomenal. An adequate magnetic lifetime for your credit card is until its expiry date and one must avoid exposure to magnetic fields and heat. But a rock's magnetic memory is forever, and the recipe for that durability includes, for igneous and metamorphic rocks, exposure to ancient fields while hot - near the Curie temperature in fact. The thermal remanent magnetism (TRM) thus produced is largely immune to later field changes at lower temperatures although luckily a fraction - a partial TRM overprint - does record later heating events, e.g., burial during major orogenies. When we lift the veil and look closely, on a microscale or nanoscale, it is perplexing to understand why paleomagnetism works so well when rocks seemingly contain so few of Néel's ideal recorders: single-domain grains with tightly coupled atomic spins. In larger grains with multiple domains, the walls between neighbouring domains move readily, like dislocations in crystals, enlarging some domains at the expense of others. This mutability makes any magnetic memory of multi-domain grains suspect. But around the threshold between single-domain and multi-domain structures - a specific grain size that varies widely from one magnetic mineral to another - there are recent predictions and observations of novel structures, including linked magnetic moments of nearby grains and interfacial moments of exsolved phases, that could go some way towards explaining why single-domain-like behaviour is so widespread. Many magnetic properties show an almost continuous variation with grain size, quite unlike the expected discontinuity at the single-domain threshold. Among these is initial susceptibility which governs a rock's induced response to weak fields like the Earth's. In particular, the Hopkinson peak in susceptibility near the Curie temperature - a potential source of "missing magnetism" in the deep lithosphere - increases steadily over at least a decade of decreasing grain size in magnetite. Single-domain recorders, in addition to their strong and long-lasting memory, have the property of TRM additivity and independence. This makes possible the Thellier method of determining paleofield intensity, a much more demanding undertaking than tracking paleomagnetic field directions, in which the ancient magnetic moment is gradually replaced by a set of partial TRMs produced in a known laboratory field. Partial TRMs produced in nature by heating during deep burial are also additive and independent. The temperature at which these overprints are removed in the laboratory yields - after correction for the very different natural and laboratory heating times - the burial temperature. This is the basis of magnetic paleothermometry. The interplay of time and temperature in TRM when combined with thermal history models provides estimates of when the global magnetic field of a planet, e.g., Mars, was born and died. But the grand conclusions so important to geophysics rest ultimately on the fidelity of the microscopic recorders in rocks and here, despite many advances, our understanding is still a work in progress.

The first direct dating of Main Central Thrust phyllonite demonstrates exhumation of the Greater Himalayan Crystalline had already taken place

NASA Astrophysics Data System (ADS)

Rajabi, Sareh; Forster, Marnie; Ahmad, Talat; Lister, Gordon

2017-04-01

Here we report the results of step-heating experiments that allow the first direct dating of the timing of movement on the Himalayan Main Central Thrust (MCT). Timing of MCT operation has, until now, been inferred based on specific tectonic models, or with data not directly attributable to MCT movement, e.g., the debatable assertion that leucogranite formation is invariably related to crustal shortening, and therefore that the MCT must already have been in operation. However the tectonic evolution may have been more complex, e.g., at times involving horizontal extension. In any case, many different thrust systems operated during India-Asia convergence, and the MCT is only one of them. It is time to move away from models and to bring geology back into the equation. Here we apply 40Ar/39Ar geochronology to directly date highly strained, phyllonitized, muscovite in the MCT above the Kullu-Rampur tectonic window (NW Indian Himalaya), showing that the timing of the shear movement lasted from 15-9 Ma. We show that these ages have been preserved because the white mica was sufficiently retentive of argon to be able to inhibit its diffusional loss at the temperatures and pressures in question. Arrhenius data from ultra-high-vacuum diffusion experiments show that deformation occurred below the closure temperature of this muscovite, for moderate cooling rates. Furthermore, we demonstrate that microscopic shear bands associated with MCT operation overprinted an earlier decussate mica growth. This decussate growth had taken place prior to ˜ 18 Ma. The decussate microstructure, together with foam textures in the host deformed quartzite, demonstrate that low deviatoric stress conditions applied during a prior period of static annealing under middle- to upper-greenschist facies conditions. In this region, therefore, the Greater Himalayan Crystalline had therefore already been significantly exhumed prior to the onset of MCT operation. The foam textures in quartzite and the decussate intergrowths of mica match in age and character the effects of the Oligo-Miocene metamorphic event that had widespread effects across this region, coeval with the operation of extensional ductile shear zones and faults of the South Tibetan Detachment (STD) system. This means that regional exhumation of the crystalline series most-likely occurred as the result of extreme extension during STD time. The MCT at this location is a relatively late structure that overprinted STD fabrics and microstructures at least five million years after the main exhumation of the crystalline series. It is widely agreed that the MCT had a pivotal role in the evolution and exhumation of the Greater Himalaya crystalline sequences. This aspect is central to models involving fold-nappes, channel flow, and wedge extrusion. All of these models imply that the crystalline core of the Himalaya was exhumed as the result of it being thrust southward by the MCT. However, there is no evidence that this is the case, and these data allow rebuttal of such models, at least in terms of the structures currently defined as representing the MCT in NW India.

Skeletal Muscle Remodeling in Response to Eccentric vs. Concentric Loading: Morphological, Molecular, and Metabolic Adaptations

PubMed Central

Franchi, Martino V.; Reeves, Neil D.; Narici, Marco V.

2017-01-01

Skeletal muscle contracts either by shortening or lengthening (concentrically or eccentrically, respectively); however, the two contractions substantially differ from one another in terms of mechanisms of force generation, maximum force production and energy cost. It is generally known that eccentric actions generate greater force than isometric and concentric contractions and at a lower metabolic cost. Hence, by virtue of the greater mechanical loading involved in active lengthening, eccentric resistance training (ECC RT) is assumed to produce greater hypertrophy than concentric resistance training (CON RT). Nonetheless, prevalence of either ECC RT or CON RT in inducing gains in muscle mass is still an open issue, with some studies reporting greater hypertrophy with eccentric, some with concentric and some with similar hypertrophy within both training modes. Recent observations suggest that such hypertrophic responses to lengthening vs. shortening contractions are achieved by different adaptations in muscle architecture. Whilst the changes in muscle protein synthesis in response to acute and chronic concentric and eccentric exercise bouts seem very similar, the molecular mechanisms regulating the myogenic adaptations to the two distinct loading stimuli are still incompletely understood. Thus, the present review aims to, (a) critically discuss the literature on the contribution of eccentric vs. concentric loading to muscular hypertrophy and structural remodeling, and, (b) clarify the molecular mechanisms that may regulate such adaptations. We conclude that, when matched for either maximum load or work, similar increase in muscle size is found between ECC and CON RT. However, such hypertrophic changes appear to be achieved through distinct structural adaptations, which may be regulated by different myogenic and molecular responses observed between lengthening and shortening contractions. PMID:28725197

Cenozoic intraplate tectonics in Central Patagonia: Record of main Andean phases in a weak upper plate

NASA Astrophysics Data System (ADS)

Gianni, G. M.; Echaurren, A.; Folguera, A.; Likerman, J.; Encinas, A.; García, H. P. A.; Dal Molin, C.; Valencia, V. A.

2017-11-01

Contraction in intraplate areas is still poorly understood relative to similar deformation at plate margins. In order to contribute to its comprehension, we study the Patagonian broken foreland (PBF) in South America whose evolution remains controversial. Time constraints of tectonic events and structural characterization of this belt are limited. Also, major causes of strain location in this orogen far from the plate margin are enigmatic. To unravel tectonic events, we studied the Cenozoic sedimentary record of the central sector of the Patagonian broken foreland (San Bernardo fold and thrust belt, 44°30‧S-46°S) and the Andes (Meseta de Chalia, 46°S) following an approach involving growth-strata detection, U-Pb geochronology and structural modeling. Additionally, we elaborate a high resolution analysis of the effective elastic thickness (Te) to examine the relation between intraplate contraction location and variations in lithospheric strength. The occurrence of Eocene growth-strata ( 44-40 Ma) suggests that contraction in the Andes and the Patagonian broken foreland was linked to the Incaic phase. Detection of synextensional deposits suggests that the broken foreland collapsed partially during Oligocene to early Miocene. During middle Miocene times, the Quechua contractional phase produced folding of Neogene volcanic rocks and olistostrome deposition at 17 Ma. Finally, the presented Te map shows that intraplate contraction related to Andean phases localized preferentially along weak lithospheric zones (Te < 15 km). Hence, the observed strain distribution in the PBF appears to be controlled by lateral variations in the lithospheric strength. Variations in this parameter could be related to thermo-mechanical weakening produced by intraplate rifting in Paleozoic-Mesozoic times.

Moral Reasoning and Religious Belief: Does Content Influence Structure?

ERIC Educational Resources Information Center

Norman, Antony D.; Richards, Herbert C.; Bear, George G.

1998-01-01

Studies the inference from Kohlbergian theory that content and structure in moral development are independent. Administered Kohlberg's moral dilemmas of life versus law, punishment versus conscience, and authority versus contract. Finds differences in choices and reasoning between students in private Christian schools and public schools, as well…

MODU marine safety: Structural inspection and readiness surveys

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

Cole, M.W.; Marucci, T.F.; Taft, D.G.

1987-11-01

Several years ago, Exxon instituted a survey of mobile offshore drilling units (MODU's) under contract to the corporation to evaluate structural integrity and readiness to respond properly to marine emergencies. This paper briefly describes results of the inspections and our on-going marine safety program. Industry activity is also highlighted.

Lightweight solar concentrator structures, phase 2

NASA Technical Reports Server (NTRS)

Williams, Brian E.; Kaplan, Richard B.

1993-01-01

This report summarizes the results of the program conducted by Ultramet under SBIR Phase 2 Contract NAS3-25418. The objective of this program was to develop lightweight materials and processes for advanced high accuracy Space Solar Concentrators using rigidized foam for the substrate structure with an integral optical surface.

75 FR 60674 - Exchange Visitor Program-Fees and Charges

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-01

.... In 2006, the Department examined its current Exchange Visitor Program fee structure for compliance.... Deloitte and Touche was awarded a contract. The new proposed fee structure was conducted under the... Standards No. 4 (SFFAS 4). In accordance with SFFAS 4, the Department used an ``activity-based costing...

Structural Damage Prediction and Analysis for Hypervelocity Impact: Consulting

NASA Technical Reports Server (NTRS)

1995-01-01

A portion of the contract NAS8-38856, 'Structural Damage Prediction and Analysis for Hypervelocity Impacts,' from NASA Marshall Space Flight Center (MSFC), included consulting which was to be documented in the final report. This attachment to the final report contains memos produced as part of that consulting.

Hospital management contracts: institutional and community perspectives.

PubMed Central

Wheeler, J R; Zuckerman, H S

1984-01-01

Previous studies have shown that external management by contract can improve the performance of managed hospitals. This article presents a conceptual framework which develops specific hypotheses concerning improved hospital operating efficiency, increased ability to meet hospital objectives, and increased ability to meet community objectives. Next, changes in the process and structure of management under contractual arrangements, based on observations from two not-for-profit hospital systems, are described. Finally, the effects of these management changes over time on hospital and community objectives are presented. These effects suggest progressive stages in the development of management contracts. The first stage focuses on stabilizing hospital financial performance. Stage two involves recruitment and retention efforts to secure necessary personnel. In the third stage, attention shifts to strategic planning and marketing. PMID:6490378

Chemical laser exhaust pipe design research

NASA Astrophysics Data System (ADS)

Sun, Yunqiang; Huang, Zhilong; Chen, Zhiqiang; Ren, Zebin; Guo, Longde

2016-10-01

In order to weaken the chemical laser exhaust gas influence of the optical transmission, a vent pipe is advised to emissions gas to the outside of the optical transmission area. Based on a variety of exhaust pipe design, a flow field characteristic of the pipe is carried out by numerical simulation and analysis in detail. The research results show that for uniform deflating exhaust pipe, although the pipeline structure is cyclical and convenient for engineering implementation, but there is a phenomenon of air reflows at the pipeline entrance slit which can be deduced from the numerical simulation results. So, this type of pipeline structure does not guarantee seal. For the design scheme of putting the pipeline contract part at the end of the exhaust pipe, or using the method of local area or tail contraction, numerical simulation results show that backflow phenomenon still exists at the pipeline entrance slit. Preliminary analysis indicates that the contraction of pipe would result in higher static pressure near the wall for the low speed flow field, so as to produce counter pressure gradient at the entrance slit. In order to eliminate backflow phenomenon at the pipe entrance slit, concerned with the pipeline type of radial size increase gradually along the flow, flow field property in the pipe is analyzed in detail by numerical simulation methods. Numerical simulation results indicate that there is not reflow phenomenon at entrance slit of the dilated duct. However the cold air inhaled in the slit which makes the temperature of the channel wall is lower than the center temperature. Therefore, this kind of pipeline structure can not only prevent the leak of the gas, but also reduce the wall temperature. In addition, compared with the straight pipe connection way, dilated pipe structure also has periodic structure, which can facilitate system integration installation.

A dihydropyridine receptor alpha1s loop region critical for skeletal muscle contraction is intrinsically unstructured and binds to a SPRY domain of the type 1 ryanodine receptor.

PubMed

Cui, Yanfang; Tae, Han-Shen; Norris, Nicole C; Karunasekara, Yamuna; Pouliquin, Pierre; Board, Philip G; Dulhunty, Angela F; Casarotto, Marco G

2009-03-01

The II-III loop of the dihydropyridine receptor (DHPR) alpha(1s) subunit is a modulator of the ryanodine receptor (RyR1) Ca(2+) release channel in vitro and is essential for skeletal muscle contraction in vivo. Despite its importance, the structure of this loop has not been reported. We have investigated its structure using a suite of NMR techniques which revealed that the DHPR II-III loop is an intrinsically unstructured protein (IUP) and as such belongs to a burgeoning structural class of functionally important proteins. The loop does not possess a stable tertiary fold: it is highly flexible, with a strong N-terminal helix followed by nascent helical/turn elements and unstructured segments. Its residual structure is loosely globular with the N and C termini in close proximity. The unstructured nature of the II-III loop may allow it to easily modify its interaction with RyR1 following a surface action potential and thus initiate rapid Ca(2+) release and contraction. The in vitro binding partner for the II-III was investigated. The II-III loop interacts with the second of three structurally distinct SPRY domains in RyR1, whose function is unknown. This interaction occurs through two preformed N-terminal alpha-helical regions and a C-terminal hydrophobic element. The A peptide corresponding to the helical N-terminal region is a common probe of RyR function and binds to the same SPRY domain as the full II-III loop. Thus the second SPRY domain is an in vitro binding site for the II-III loop. The possible in vivo role of this region is discussed.

A deformable spherical planet exploration robot

NASA Astrophysics Data System (ADS)

Liang, Yi-shan; Zhang, Xiu-li; Huang, Hao; Yang, Yan-feng; Jin, Wen-tao; Sang, Zhong-xun

2013-03-01

In this paper, a deformable spherical planet exploration robot has been introduced to achieve the task of environmental detection in outer space or extreme conditions. The robot imitates the morphology structure and motion mechanism of tumbleweeds. The robot is wind-driven. It consists of an axle, a spherical steel skeleton and twelve airbags. The axle is designed as two parts. The robot contracts by contracting the two-part axle. The spherical robot installs solar panels to provide energy for its control system.

A Real Options Approach to Valuing the Risk Transfer in a Multi-Year Procurement Contract

DTIC Science & Technology

2009-10-01

asset follows a Brownian motion process where the returns have a lognormal distribution. H. BLACK-SCHOLES MODEL The value of the put option p on...risk in a firm-fixed-price contract. The government also provides interest-free financing that can greatly reduce the amount of capital a contractor...structured finance and credit default swap applications. 8 E. OPTIONS THEORY We will use closed form BS-type option pricing methods to estimate the

A-3 Test Stand construction update

NASA Technical Reports Server (NTRS)

2007-01-01

The concrete foundation placed Dec. 18 (foreground) for Stennis Space Center's future A-3 Test Stand has almost completely cured by early January, according to Bo Clarke, NASA's contracting officer technical representative for the foundation contract. By late December, construction on foundations for many of the test stand's support structures - diffuser, liquid oxygen, isopropyl alcohol and water tanks and gaseous nitrogen bottle battery - had begun with the installation of (background) `mud slabs.' The slabs provide a working surface for the reinforcing steel and foundation forms.