Release of volatiles from a possible cryovolcano from near-infrared imaging of Titan

USGS Publications Warehouse

Sotin, Christophe; Jaumann, R.; Buratti, B.J.; Brown, R.H.; Clark, R.N.; Soderblom, L.A.; Baines, K.H.; Bellucci, G.; Bibring, J.-P.; Capaccioni, F.; Cerroni, P.; Combes, M.; Coradini, A.; Cruikshank, D.P.; Drossart, P.; Formisano, V.; Langevin, Y.; Matson, D.L.; McCord, T.B.; Nelson, R.M.; Nicholson, P.D.; Sicardy, B.; Lemouelic, S.; Rodriguez, S.; Stephan, K.; Scholz, C.K.

2005-01-01

Titan is the only satellite in our Solar System with a dense atmosphere. The surface pressure is 1.5 bar (ref. 1) and, similar to the Earth, N 2 is the main component of the atmosphere. Methane is the second most important component, but it is photodissociated on a timescale of 10 years (ref. 3). This short timescale has led to the suggestion that Titan may possess a surface or subsurface reservoir of hydrocarbons to replenish the atmosphere. Here we report near-infrared images of Titan obtained on 26 October 2004 by the Cassini spacecraft. The images show that a widespread methane ocean does not exist; subtle albedo variations instead suggest topographical variations, as would be expected for a more solid (perhaps icy) surface. We also find a circular structure ???30 km in diameter that does not resemble any features seen on other icy satellites. We propose that the structure is a dome formed by upwelling icy plumes that release methane into Titan's atmosphere.

Release of volatiles from a possible cryovolcano from near-infrared imaging of Titan.

PubMed

Sotin, C; Jaumann, R; Buratti, B J; Brown, R H; Clark, R N; Soderblom, L A; Baines, K H; Bellucci, G; Bibring, J-P; Capaccioni, F; Cerroni, P; Combes, M; Coradini, A; Cruikshank, D P; Drossart, P; Formisano, V; Langevin, Y; Matson, D L; McCord, T B; Nelson, R M; Nicholson, P D; Sicardy, B; LeMouelic, S; Rodriguez, S; Stephan, K; Scholz, C K

2005-06-09

Titan is the only satellite in our Solar System with a dense atmosphere. The surface pressure is 1.5 bar (ref. 1) and, similar to the Earth, N2 is the main component of the atmosphere. Methane is the second most important component, but it is photodissociated on a timescale of 10(7) years (ref. 3). This short timescale has led to the suggestion that Titan may possess a surface or subsurface reservoir of hydrocarbons to replenish the atmosphere. Here we report near-infrared images of Titan obtained on 26 October 2004 by the Cassini spacecraft. The images show that a widespread methane ocean does not exist; subtle albedo variations instead suggest topographical variations, as would be expected for a more solid (perhaps icy) surface. We also find a circular structure approximately 30 km in diameter that does not resemble any features seen on other icy satellites. We propose that the structure is a dome formed by upwelling icy plumes that release methane into Titan's atmosphere.

Complex Topographic Feature Ontology Patterns

USGS Publications Warehouse

Varanka, Dalia E.; Jerris, Thomas J.

2015-01-01

Semantic ontologies are examined as effective data models for the representation of complex topographic feature types. Complex feature types are viewed as integrated relations between basic features for a basic purpose. In the context of topographic science, such component assemblages are supported by resource systems and found on the local landscape. Ontologies are organized within six thematic modules of a domain ontology called Topography that includes within its sphere basic feature types, resource systems, and landscape types. Context is constructed not only as a spatial and temporal setting, but a setting also based on environmental processes. Types of spatial relations that exist between components include location, generative processes, and description. An example is offered in a complex feature type ‘mine.’ The identification and extraction of complex feature types are an area for future research.

Acousto-Optic Technology for Topographic Feature Extraction and Image Analysis.

DTIC Science & Technology

1981-03-01

This report contains all findings of the acousto - optic technology study for feature extraction conducted by Deft Laboratories Inc. for the U.S. Army...topographic feature extraction and image analysis using acousto - optic (A-O) technology. A conclusion of this study was that A-O devices are potentially

Airborne imaging spectrometer data of the Ruby Mountains, Montana: Mineral discrimination using relative absorption band-depth images

USGS Publications Warehouse

Crowley, J.K.; Brickey, D.W.; Rowan, L.C.

1989-01-01

Airborne imaging spectrometer data collected in the near-infrared (1.2-2.4 ??m) wavelength range were used to study the spectral expression of metamorphic minerals and rocks in the Ruby Mountains of southwestern Montana. The data were analyzed by using a new data enhancement procedure-the construction of relative absorption band-depth (RBD) images. RBD images, like bandratio images, are designed to detect diagnostic mineral absorption features, while minimizing reflectance variations related to topographic slope and albedo differences. To produce an RBD image, several data channels near an absorption band shoulder are summed and then divided by the sum of several channels located near the band minimum. RBD images are both highly specific and sensitive to the presence of particular mineral absorption features. Further, the technique does not distort or subdue spectral features as sometimes occurs when using other data normalization methods. By using RBD images, a number of rock and soil units were distinguished in the Ruby Mountains including weathered quartz - feldspar pegmatites, marbles of several compositions, and soils developed over poorly exposed mica schists. The RBD technique is especially well suited for detecting weak near-infrared spectral features produced by soils, which may permit improved mapping of subtle lithologic and structural details in semiarid terrains. The observation of soils rich in talc, an important industrial commodity in the study area, also indicates that RBD images may be useful for mineral exploration. ?? 1989.

Elements of the Chicxulub Impact Structure as revealed in SRTM and surface GPS topographic data

NASA Astrophysics Data System (ADS)

Kobrick, M.; Kinsland, G. L.; Sanchez, G.; Cardador, M. H.

2003-04-01

Pope et al have utilized elevations from the Petroleos Mexicanos (PEMEX) gravity data files to show that the main component of the surface expression of the Chicxu-lub Impact Structure is a roughly semi-circular, low-relief depression about 90 km in diameter. They also identified other topographic features and the elements of the buried impact which possibly led to the development of these features. Kinsland et al presented a connection between these topographic anomalies, small gravity anomalies and buried structure of the impact. Shaded relief images from recently acquired SRTM elevation data clearly show the circular depression of the crater and the moat/cenote ring. In addition we can readily identify Inner trough 1, Inner trough 2 and Outer trough as defined by Pope et al. The agreement between the topographic maps of Pope et al, Kinsland et al and SRTM data are remarkable considering that the distribution and types of data in the sets are so different. We also have ground topographic data collected with a special "autonomous differ-ential GPS" system during summer 2002. Profiles from these data generally agree with both the gravity data based topographic maps and profiles extracted from the SRTM data. Preliminary analyses of our new data, SRTM and GPS, have uncovered features not previously recognized: 1) as shown by the GPS data the moat/cenote ring consists of two distinct depressions separated by about 10 km...perhaps separate ring faults, 2) in the SRTM data over the southern part of the crater and on southward for perhaps 20 km beyond the moat/ cenote ring there exists a pattern, as yet unexplained, of roughly concentric topographic features whose center lies at about 21deg 40min N and 89deg 25min W, about 50km NNE of the moat/cenote ring center. The corroboration and better definition of the previously recognized topographic features yielded by the two new forms of data strengthens the cases for these fea-tures and for their relevance to the underlying collapsed crater structure.

Techniques for noise removal and registration of TIMS data

USGS Publications Warehouse

Hummer-Miller, S.

1990-01-01

Extracting subtle differences from highly correlated thermal infrared aircraft data is possible with appropriate noise filters, constructed and applied in the spatial frequency domain. This paper discusses a heuristic approach to designing noise filters for removing high- and low-spatial frequency striping and banding. Techniques for registering thermal infrared aircraft data to a topographic base using Thematic Mapper data are presented. The noise removal and registration techniques are applied to TIMS thermal infrared aircraft data. -Author

Graphene transport mediated by micropatterned substrates

NASA Astrophysics Data System (ADS)

Hinnefeld, J. Henry; Gill, Stephen T.; Mason, Nadya

2018-04-01

Engineered substrates offer a promising avenue towards graphene devices having tunable properties. In particular, topographically patterned substrates can expose unique behavior due to their ability to induce local variations in strain and electrostatic doping. However, to explore the range of possible science and applications, it is important to create topographic substrates that both have tunable features and are suitable for transport measurements. In this letter, we describe the fabrication of tunable, topographically patterned substrates suitable for transport measurements. We report both optical and transport measurements of graphene devices fabricated on these substrates and demonstrate the characteristic strain and local doping behavior induced by the topographic features.

Extraction and representation of nested catchment areas from digital elevation models in lake-dominated topography

NASA Astrophysics Data System (ADS)

Mackay, D. Scott; Band, Lawrence E.

1998-04-01

This paper presents a new method for extracting flow directions, contributing (upslope) areas, and nested catchments from digital elevation models in lake-dominated areas. Existing tools for acquiring descriptive variables of the topography, such as surface flow directions and contributing areas, were developed for moderate to steep topography. These tools are typically difficult to apply in gentle topography owing to limitations in explicitly handling lakes and other flat areas. This paper addresses the problem of accurately representing general topographic features by first identifying distinguishing features, such as lakes, in gentle topography areas and then using these features to guide the search for topographic flow directions and catchment marking. Lakes are explicitly represented in the topology of a watershed for use in water routing. Nonlake flat features help guide the search for topographic flow directions in areas of low signal to noise. This combined feature-based and grid-based search for topographic features yields improved contributing areas and watershed boundaries where there are lakes and other flat areas. Lakes are easily classified from remotely sensed imagery, which makes automated representation of lakes as subsystems within a watershed system tractable with widely available data sets.

Structural interpretations based on ERTS-1 imagery, Bighorn Region, Wyoming-Montana

NASA Technical Reports Server (NTRS)

Hoppin, R. A.

1973-01-01

Structural analysis is being carried out on bands MSS 5 and 7 of scene 1085-17294. Geologic strucutre is primarily revealed in the topographic relief and drainage. Topographic linears are particularly well developed in the bighorn uplift. Many of these occur along known faults and shear zones in the Precambrian core; several have not been previously mapped. These linears, however, do not continue into the younger rocks of the flanks or do so in a much less marked manner than in the core. Linears are far less abundant in the basin or are manifested only in very subtle tonal contrasts and somewhat straight drainage segments. Some of the linears are aligned along trends previously postulated on the basis of surface mapping to be lineaments. The imagery reveals little or no evidence of strike-slip displacements along these lineaments.

U.S. Army Environmental Restoration Programs Guidance Manual

DTIC Science & Technology

1998-04-01

without delay. In addition to sampling, the SI usually includes a reconnaissance of the site’s layout, surrounding topographical features , and the...chemical monitoring of some, but not necessarily all, of the following: 2.1.1 Surface Features (topographic mapping, etc.) (natural and manmade features ...include some, but not necessarily all, of the following: 3.1.1 Surface Features 3.1.2 Meteorology 3.1.3 Surface-Water Hydrology 3.1.4 Geology 3.1.5

Improving the signal subtle feature extraction performance based on dual improved fractal box dimension eigenvectors

NASA Astrophysics Data System (ADS)

Chen, Xiang; Li, Jingchao; Han, Hui; Ying, Yulong

2018-05-01

Because of the limitations of the traditional fractal box-counting dimension algorithm in subtle feature extraction of radiation source signals, a dual improved generalized fractal box-counting dimension eigenvector algorithm is proposed. First, the radiation source signal was preprocessed, and a Hilbert transform was performed to obtain the instantaneous amplitude of the signal. Then, the improved fractal box-counting dimension of the signal instantaneous amplitude was extracted as the first eigenvector. At the same time, the improved fractal box-counting dimension of the signal without the Hilbert transform was extracted as the second eigenvector. Finally, the dual improved fractal box-counting dimension eigenvectors formed the multi-dimensional eigenvectors as signal subtle features, which were used for radiation source signal recognition by the grey relation algorithm. The experimental results show that, compared with the traditional fractal box-counting dimension algorithm and the single improved fractal box-counting dimension algorithm, the proposed dual improved fractal box-counting dimension algorithm can better extract the signal subtle distribution characteristics under different reconstruction phase space, and has a better recognition effect with good real-time performance.

Geologic applications of thermal-inertia mapping from satellite. [Powder River, Wyoming; Cubeza Prieta, Arizona, and Yellowstone National Park

NASA Technical Reports Server (NTRS)

Offield, T. W. (Principal Investigator); Watson, K.; Hummer-Miller, S.

1981-01-01

In the Powder River Basin, Wyo., narrow geologic units having thermal inertias which contrast with their surroundings can be discriminated in optimal images. A few subtle thermal inertia anomalies coincide with areas of helium leakage believed to be associated with deep oil and gas concentrations. The most important results involved delineation of tectonic framework elements some of which were not previously recognized. Thermal and thermal inertia images also permit mapping of geomorphic textural domains. A thermal lineament appears to reveal a basement discontinuity which involves the Homestake Mine in the Black Hill, a zone of Tertiary igneous activity and facies control in oil producing horizons. Applications of these data to the Cabeza Prieta, Ariz., area illustrate their potential for igneous rock type discrimination. Extension to Yellowstone National Park resulted in the detection of additional structural information but surface hydrothermal features could not be distinguished with any confidence. A thermal inertia mapping algorithm, a fast and accurate image registration technique, and an efficient topographic slope and elevation correction method were developed.

Does Translational Symmetry Matter on the Micro Scale? Fibroblastic and Osteoblastic Interactions with the Topographically Distinct Poly(ε-caprolactone)/Hydroxyapatite Thin Films

PubMed Central

2015-01-01

Material composition and topography of the cell-contacting material interface are important considerations in the design of biomaterials at the nano and micro scales. This study is one of the first to have assessed the osteoblastic response to micropatterned polymer–ceramic composite surfaces. In particular, the effect of topographic variations of composite poly(ε-caprolactone)/hydroxyapatite (PCL/HAp) films on viability, proliferation, migration and osteogenesis of fibroblastic and osteoblastic MC3T3-E1 cells was evaluated. To that end, three different micropatterned PCL/HAp films were compared: flat and textured, the latter of which included films comprising periodically arranged and randomly distributed oval topographic features 10 μm in diameter, 20 μm in separation and 10 μm in height, comparable to the dimensions of MC3T3-E1 cells. PCL/HAp films were fabricated by the combination of a bottom-up, soft chemical synthesis of the ceramic, nanoparticulate phase and a top-down, photolithographic technique for imprinting fine, microscale features on them. X-ray diffraction analysis indicated an isotropic orientation of both the polymeric chains and HAp crystallites in the composite samples. Biocompatibility tests indicated no significant decrease in their viability when grown on PCL/HAp films. Fibroblast proliferation and migration onto PCL/HAp films proceeded slower than on the control borosilicate glass, with the flat composite film fostering more cell migration activity than the films containing topographic features. The gene expression of seven analyzed osteogenic markers, including procollagen type I, osteocalcin, osteopontin, alkaline phosphatase, and the transcription factors Runx2 and TGFβ-1, was, however, consistently upregulated in cells grown on PCL/HAp films comprising periodically ordered topographic features, suggesting that the higher levels of symmetry of the topographic ordering impose a moderate mechanochemical stress on the adherent cells and thus promote a more favorable osteogenic response. The obtained results suggest that topography can be a more important determinant of the cell/surface interaction than the surface chemistry and/or stiffness as well as that the regularity of the distribution of topographic features can be a more important variable than the topographic features per se. PMID:25014232

Interactions between hyporheic flow produced by stream meanders, bars, and dunes

USGS Publications Warehouse

Stonedahl, Susa H.; Harvey, Judson W.; Packman, Aaron I.

2013-01-01

Stream channel morphology from grain-scale roughness to large meanders drives hyporheic exchange flow. In practice, it is difficult to model hyporheic flow over the wide spectrum of topographic features typically found in rivers. As a result, many studies only characterize isolated exchange processes at a single spatial scale. In this work, we simulated hyporheic flows induced by a range of geomorphic features including meanders, bars and dunes in sand bed streams. Twenty cases were examined with 5 degrees of river meandering. Each meandering river model was run initially without any small topographic features. Models were run again after superimposing only bars and then only dunes, and then run a final time after including all scales of topographic features. This allowed us to investigate the relative importance and interactions between flows induced by different scales of topography. We found that dunes typically contributed more to hyporheic exchange than bars and meanders. Furthermore, our simulations show that the volume of water exchanged and the distributions of hyporheic residence times resulting from various scales of topographic features are close to, but not linearly additive. These findings can potentially be used to develop scaling laws for hyporheic flow that can be widely applied in streams and rivers.

Topographic attributes as a guide for automated detection or highlighting of geological features

NASA Astrophysics Data System (ADS)

Viseur, Sophie; Le Men, Thibaud; Guglielmi, Yves

2015-04-01

Photogrammetry or LIDAR technology combined with photography allow geoscientists to obtain 3D high-resolution numerical representations of outcrops, generally termed as Digital Outcrop Models (DOM). For over a decade, these 3D numerical outcrops serve as support for precise and accurate interpretations of geological features such as fracture traces or plans, strata, facies mapping, etc. These interpretations have the benefit to be directly georeferenced and embedded into the 3D space. They are then easily integrated into GIS or geomodeler softwares for modelling in 3D the subsurface geological structures. However, numerical outcrops generally represent huge data sets that are heavy to manipulate and hence to interpret. This may be particularly tedious as soon as several scales of geological features must be investigated or as geological features are very dense and imbricated. Automated tools for interpreting geological features from DOMs would be then a significant help to process these kinds of data. Such technologies are commonly used for interpreting seismic or medical data. However, it may be noticed that even if many efforts have been devoted to easily and accurately acquire 3D topographic point clouds and photos and to visualize accurate 3D textured DOMs, few attentions have been paid to the development of algorithms for automated detection of the geological structures from DOMs. The automatic detection of objects on numerical data generally assumes that signals or attributes computed from this data allows the recognition of the targeted object boundaries. The first step consists then in defining attributes that highlight the objects or their boundaries. For DOM interpretations, some authors proposed to use differential operators computed on the surface such as normal or curvatures. These methods generally extract polylines corresponding to fracture traces or bed limits. Other approaches rely on the PCA technology to segregate different topographic plans. This approach assume that structural or sedimentary features coincide with topographic surface parts. In this work, several topographic attributes are proposed to highlight geological features on outcrops. Among them, differential operators are used but also combined and processed to display particular topographic shapes. Moreover, two kinds of attributes are used: unsupervised and supervised attributes. The supervised attributes integrate an a priori knowledge about the objects to extract (e.g.: a preferential orientation of fracture surfaces, etc.). This strategy may be compared to the one used for seismic interpretation. Indeed, many seismic attributes have been proposed to highlight geological structures hardly observable due to data noise. The same issue exist with topographic data: plants, erosions, etc. generate noise that make interpretation sometimes hard. The proposed approach has been applied on real case studies to show how it could help the interpretation of geological features. The obtained 'topographic attributes' are shown and discussed.

Perspective View, Kamchatka Peninsula, Russia

NASA Technical Reports Server (NTRS)

2000-01-01

This perspective view shows the western side of the volcanically active Kamchatka Peninsula, Russia. The data are from the first C-band mapping swath of the Shuttle Radar Topography Mission (SRTM). In the foreground is the broad, flat floodplain of the Amanina River, shown in blue. In background of the image is the Sredinnyy Khrebet, the volcanic mountain range that makes up the 3spine2 of the peninsula. The cluster of hills in the upper right is a field of small dormant volcanoes. High resolution SRTM topographic data will be used by geologists to study how volcanoes form and understand the hazards posed by future eruptions.

This shaded relief perspective view was generated using topographic data from the Shuttle Radar Topography Mission. A computer-generated artificial light source illuminates the elevation data to produce a pattern of light and shadows. Slopes facing the light appear bright, while those facing away are shaded. On flatter surfaces, the pattern of light and shadows can reveal subtle features in the terrain. Colors show the elevation as measured by SRTM. Colors range from blue at the lowest elevations to white at the highest elevations. This image contains about 2300 meters (7500 feet) of total relief. To emphasize subtle differences in topography, the relief is exaggerated by a factor of 5.

The Shuttle Radar Topography Mission (SRTM), launched on February 11,2000, uses the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. The mission is designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, an additional C-band imaging antenna and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration (NASA), the National Imagery and Mapping Agency (NIMA) and the German (DLR) and Italian (ASI) space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Earth Science Enterprise, Washington, DC.

Size: 80 km (50 miles) x 100 km (62 miles) Location: 57.5 deg. North lat., 158.8 deg. East lon. Orientation: View toward the East Original Data Resolution: 30 meters (99 feet) Date Acquired: February 12, 2000

Tectonic geomorphology of the New Madrid seismic zone based on imaging of digital topographic data

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

Mayer, L.

1993-03-01

Topographic analysis using digital elevation data of the New Madrid region focuses on topographic features that occur at several spatial scales and can be used to delineate distinct anomalies. In this region, topographic anomalies occur as domal or elongate uplifts and bowl-shaped depressions approximately 1--10 km in size, topographic lineaments, and differences in topographic blocking across 50 km long boundaries. In order to fully explain these topographic anomalies, tectonic processes may be required. Imaging is based on digital topographic data from USGS 30 arc-second, 3 arc-second, and 30 m resolutions. Imaging of these data uses standard imaging processing techniques tomore » examine topography within the contexts of geomorphological hypothesis testing. A good example is the use of thresholding to highlight areas of unusually high elevation given the hypothesis of fluvial landscape architecture. Thresholding delineates topographic features such as the Tiptonville dome which is strongly believed to be tectonic in origin. To determine the pattern of topographic blocking, defined as a pattern that topography assumes when constrained by active forces other than erosion alone, low frequency passing spatial convolutions are used as filters and the resulting data are sliced into blocks according to pseudoelevations that produce a stable block pattern. The resultant blocks are analyzed according to its structural pattern of block size and block orientation. This analysis suggests that a topographic boundary cuts across the Mississippi embayment from near the Newport pluton on the west, to the area south of Memphis on east.« less

Spatial Relation Predicates in Topographic Feature Semantics

USGS Publications Warehouse

Varanka, Dalia E.; Caro, Holly K.

2013-01-01

Topographic data are designed and widely used for base maps of diverse applications, yet the power of these information sources largely relies on the interpretive skills of map readers and relational database expert users once the data are in map or geographic information system (GIS) form. Advances in geospatial semantic technology offer data model alternatives for explicating concepts and articulating complex data queries and statements. To understand and enrich the vocabulary of topographic feature properties for semantic technology, English language spatial relation predicates were analyzed in three standard topographic feature glossaries. The analytical approach drew from disciplinary concepts in geography, linguistics, and information science. Five major classes of spatial relation predicates were identified from the analysis; representations for most of these are not widely available. The classes are: part-whole (which are commonly modeled throughout semantic and linked-data networks), geometric, processes, human intention, and spatial prepositions. These are commonly found in the ‘real world’ and support the environmental science basis for digital topographical mapping. The spatial relation concepts are based on sets of relation terms presented in this chapter, though these lists are not prescriptive or exhaustive. The results of this study make explicit the concepts forming a broad set of spatial relation expressions, which in turn form the basis for expanding the range of possible queries for topographical data analysis and mapping.

Airborne spectroradiometry: The application of AIS data to detecting subtle mineral absorption features

NASA Technical Reports Server (NTRS)

Cocks, T. D.; Green, A. A.

1986-01-01

Analysis of Airborne Imaging Spectrometer (AIS) data acquired in Australia has revealed a number of operational problems. Horizontal striping in AIS imagery and spectral distortions due to order overlap were investigated. Horizontal striping, caused by grating position errors can be removed with little or no effect on spectral details. Order overlap remains a problem that seriously compromises identification of subtle mineral absorption features within AIS spectra. A spectrometric model of the AIS was developed to assist in identifying spurious spectral features, and will be used in efforts to restore the spectral integrity of the data.

Effects of topographic features on postfire exposed mineral soil in small watersheds

Treesearch

Mariana Dobre; Joan Q. Wu; William J. Elliot; Ina S. Miller; Theresa B. Jain

2014-01-01

Exposed mineral soil is an immediate result of forest fires with direct relevance on surface runoff and soil erosion. The goal of this study was to determine which topographic features influence the distribution of exposed mineral soil following wildfire in forested watersheds. In a field investigation 2 months after a simulated wildfire, ground cover was measured and...

Modelling of Singapore's topographic transformation based on DEMs

NASA Astrophysics Data System (ADS)

Wang, Tao; Belle, Iris; Hassler, Uta

2015-02-01

Singapore's topography has been heavily transformed by industrialization and urbanization processes. To investigate topographic changes and evaluate soil mass flows, historical topographic maps of 1924 and 2012 were employed, and basic topographic features were vectorized. Digital elevation models (DEMs) for the two years were reconstructed based on vector features. Corresponding slope maps, a surface difference map and a scatter plot of elevation changes were generated and used to quantify and categorize the nature of the topographic transformation. The surface difference map is aggregated into five main categories of changes: (1) areas without significant height changes, (2) lowered-down areas where hill ranges were cut down, (3) raised-up areas where valleys and swamps were filled in, (4) reclaimed areas from the sea, and (5) new water-covered areas. Considering spatial proximity and configurations of different types of changes, topographic transformation can be differentiated as either creating inland flat areas or reclaiming new land from the sea. Typical topographic changes are discussed in the context of Singapore's urbanization processes. The two slope maps and elevation histograms show that generally, the topographic surface of Singapore has become flatter and lower since 1924. More than 89% of height changes have happened within a range of 20 m and 95% have been below 40 m. Because of differences in land surveying and map drawing methods, uncertainties and inaccuracies inherent in the 1924 topographic maps are discussed in detail. In this work, a modified version of a traditional scatter plot is used to present height transformation patterns intuitively. This method of deriving categorical maps of topographical changes from a surface difference map can be used in similar studies to qualitatively interpret transformation. Slope maps and histograms were also used jointly to reveal additional patterns of topographic change.

Location of Viking 1 Lander on the surface of Mars

USGS Publications Warehouse

Morris, E.C.; Jones, K.L.; Berger, J.P.

1978-01-01

A location of the Viking 1 Lander on the surface of Mars has been determined by correlating topographic features in the lander pictures with similar features in the Viking orbiter pictures. Radio tracking data narrowed the area of search for correlating orbiter and lander features and an area was found on the orbiter pictures in which there is good agreement with topographic features on the lander pictures. This location, when plotted on the 1:250,000 scale photomosaic of the Yorktown Region of Mars (U.S. Geological Survey, 1977) is at 22.487??N latitude and 48.041??W longitude. ?? 1978.

Form drag in rivers due to small-scale natural topographic features: 1. Regular sequences

USGS Publications Warehouse

Kean, J.W.; Smith, J.D.

2006-01-01

Small-scale topographic features are commonly found on the boundaries of natural rivers, streams, and floodplains. A simple method for determining the form drag on these features is presented, and the results of this model are compared to laboratory measurements. The roughness elements are modeled as Gaussian-shaped features defined in terms of three parameters: a protrusion height, H; a streamwise length scale, ??; and a spacing between crests, ??. This shape is shown to be a good approximation to a wide variety of natural topographic bank features. The form drag on an individual roughness element embedded in a series of identical elements is determined using the drag coefficient of the individual element and a reference velocity that includes the effects of roughness elements further upstream. In addition to calculating the drag on each element, the model determines the spatially averaged total stress, skin friction stress, and roughness height of the boundary. The effects of bank roughness on patterns of velocity and boundary shear stress are determined by combining the form drag model with a channel flow model. The combined model shows that drag on small-scale topographic features substantially alters the near-bank flow field. These methods can be used to improve predictions of flow resistance in rivers and to form the basis for fully predictive (no empirically adjusted parameters) channel flow models. They also provide a foundation for calculating the near-bank boundary shear stress fields necessary for determining rates of sediment transport and lateral erosion.

Characterizing nanoscale topography of the aortic heart valve basement membrane for tissue engineering heart valve scaffold design.

PubMed

Brody, Sarah; Anilkumar, Thapasimuthu; Liliensiek, Sara; Last, Julie A; Murphy, Christopher J; Pandit, Abhay

2006-02-01

A fully effective prosthetic heart valve has not yet been developed. A successful tissue-engineered valve prosthetic must contain a scaffold that fully supports valve endothelial cell function. Recently, topographic features of scaffolds have been shown to influence the behavior of a variety of cell types and should be considered in rational scaffold design and fabrication. The basement membrane of the aortic valve endothelium provides important parameters for tissue engineering scaffold design. This study presents a quantitative characterization of the topographic features of the native aortic valve endothelial basement membrane; topographical features were measured, and quantitative data were generated using scanning electron microscopy (SEM), atomic force microscopy (AFM), transmission electron microscopy (TEM), and light microscopy. Optimal conditions for basement membrane isolation were established. Histological, immunohistochemical, and TEM analyses following decellularization confirmed basement membrane integrity. SEM and AFM photomicrographs of isolated basement membrane were captured and quantitatively analyzed. The basement membrane of the aortic valve has a rich, felt-like, 3-D nanoscale topography, consisting of pores, fibers, and elevations. All features measured were in the sub-100 nm range. No statistical difference was found between the fibrosal and ventricular surfaces of the cusp. These data provide a rational starting point for the design of extracellular scaffolds with nanoscale topographic features that mimic those found in the native aortic heart valve basement membrane.

Characterizing Nanoscale Topography of the Aortic Heart Valve Basement Membrane for Tissue Engineering Heart Valve Scaffold Design

PubMed Central

BRODY, SARAH; ANILKUMAR, THAPASIMUTHU; LILIENSIEK, SARA; LAST, JULIE A.; MURPHY, CHRISTOPHER J.; PANDIT, ABHAY

2016-01-01

A fully effective prosthetic heart valve has not yet been developed. A successful tissue-engineered valve prosthetic must contain a scaffold that fully supports valve endothelial cell function. Recently, topographic features of scaffolds have been shown to influence the behavior of a variety of cell types and should be considered in rational scaffold design and fabrication. The basement membrane of the aortic valve endothelium provides important parameters for tissue engineering scaffold design. This study presents a quantitative characterization of the topographic features of the native aortic valve endothelial basement membrane; topographical features were measured, and quantitative data were generated using scanning electron microscopy (SEM), atomic force microscopy (AFM), transmission electron microscopy (TEM), and light microscopy. Optimal conditions for basement membrane isolation were established. Histological, immunohistochemical, and TEM analyses following decellularization confirmed basement membrane integrity. SEM and AFM photomicrographs of isolated basement membrane were captured and quantitatively analyzed. The basement membrane of the aortic valve has a rich, felt-like, 3-D nanoscale topography, consisting of pores, fibers, and elevations. All features measured were in the sub-100 nm range. No statistical difference was found between the fibrosal and ventricular surfaces of the cusp. These data provide a rational starting point for the design of extracellular scaffolds with nanoscale topographic features that mimic those found in the native aortic heart valve basement membrane. PMID:16548699

The role of topographic structure and soil macrofauna presence at spoil heaps during spontaneous succession.

NASA Astrophysics Data System (ADS)

Walmsley, Alena; Vachová, Pavla; Vach, Marek

2016-04-01

This research was investigating whether topographic features, which determine soil nutrient and moisture distribution, in combination with soil fauna (wireworm and earthworm) presence, affect plant community composition at a spontaneously revegetated post mining area with an undulating surface. Two sites of different age with 3 types of topographic features were selected, soil moisture and nutrient content were measured, plant community composition and soil macrofauna community was sampled at each position. Wireworms were present at all positions and were most abundant at bottoms of waves at the younger site; their presence was correlated with several plant species, but the direction of the interaction isn't clear. Earthworms were only present at the older site and had highest abundance at flat sections. Earthworm presence affected the amount of nitrogen in soil - the most nitrogen content was at the site with highest earthworm density and was followed by higher diversity of plant community. The plant community composition was generally correlated with plant available nutrient content - especially P and N. We infer that topographic features affect nutrient and soil fauna distribution, which consequently influences plant community composition.

Paleo-earthquake Analysis from the Morphologic Features of Unconsolidated-sediment Fault Scarp: An Example from Dushanzi Thrust Fault in the Northern Tianshan, China

NASA Astrophysics Data System (ADS)

Wei, Z.; He, H.

2016-12-01

Fault scarp is important specific tectonic landform caused by surface-rupture earthquake. The morphology of the fault scarp in unconsolidated sediment could evolve in a predictable, time-dependent diffusion model. As a result, the investigation of fault-generated fault scarps is a prevalent technique used to study fault activity, geomorphic evolution, and the recurrence of faulting events. Addition to obtainment of cumulative displacement, gradient changes, i.e. slope breaks, in the morphology of fault scarps could indicate multiple rupture events along an active fault. In this study, we exacted a large set of densely spaced topographic profiles across fault scarp from LiDAR-derive DEM to detect subtle changes in the fault scarp geometry at the Dushanzi trust fault in the Northern Tianshan, China. Several slope breaks in topographic profiles can be identified, which may represent repeated rupture at the investigated fault. The number of paleo-earthquakes derived from our analysis is 4-3, well in agreement with the investigation results from the paleoseismological trenches. Statistical analysis results show that the scarp height of fault scarp with one slope break is 0.75±0.12 (mean value ±1 standard deviation) m representing the last incremental displacement during earthquakes; the height of fault scarp with two slope breaks is 1.86±0.32 m, and the height of fault scarp with three-four slope break is 6.45±1.44 m. Our approach enables us to obtain paleo-earthquake information from geomorphological analysis of fault scarps, and to assess the multiple rupture history of a complex fault system.

Parahippocampal epilepsy with subtle dysplasia: A cause of "imaging negative" partial epilepsy.

PubMed

Pillay, Neelan; Fabinyi, Gavin C A; Myles, Terry S; Fitt, Gregory J; Berkovic, Samuel F; Jackson, Graeme D

2009-12-01

Lesion-negative refractory partial epilepsy is a major challenge in the assessment of patients for potential surgery. Finding a potential epileptogenic lesion simplifies assessment and is associated with good outcome. Here we describe imaging features of subtle parahippocampal dysplasia in five cases that were initially assessed as having imaging-negative frontal or temporal lobe epilepsy. We analyzed the clinical and imaging features of five patients with seizures from the parahippocampal region. Five patients had subtle but distinctive magnetic resonance imaging (MRI) abnormalities in the parahippocampal gyrus. This was a unilateral signal abnormality in the parahippocampal white matter extending into gray matter on heavily T(1)- and T(2)-weighted images with relative preservation of the gray-white matter boundary on T(1)-weighted volume sequences. Only one of these patients had typical electroclinical unilateral temporal lobe epilepsy (TLE); one mimicked frontal lobe epilepsy, two showed bitemporal seizures, and one had unlocalized partial seizures. All have had surgery; four are seizure-free (one has occasional auras only, follow-up 6 months to 10 years), and one has a >50% seizure reduction. Histopathologic evaluation suggested dysplastic features in the surgical specimens in all. In patients with lesion-negative partial epilepsy with frontal or temporal semiology, or in cases with apparent bitemporal seizures, subtle parahippocampal abnormalities should be carefully excluded. Recognizing the MRI findings of an abnormal parahippocampal gyrus can lead to successful surgery without invasive monitoring, despite apparently incongruent electroclinical features.

Characterizing Arctic Sea Ice Topography Using High-Resolution IceBridge Data

NASA Technical Reports Server (NTRS)

Petty, Alek; Tsamados, Michel; Kurtz, Nathan; Farrell, Sinead; Newman, Thomas; Harbeck, Jeremy; Feltham, Daniel; Richter-Menge, Jackie

2016-01-01

We present an analysis of Arctic sea ice topography using high resolution, three-dimensional, surface elevation data from the Airborne Topographic Mapper, flown as part of NASA's Operation IceBridge mission. Surface features in the sea ice cover are detected using a newly developed surface feature picking algorithm. We derive information regarding the height, volume and geometry of surface features from 2009-2014 within the Beaufort/Chukchi and Central Arctic regions. The results are delineated by ice type to estimate the topographic variability across first-year and multi-year ice regimes.

Dental senescence in a long-lived primate links infant survival to rainfall

PubMed Central

King, Stephen J.; Arrigo-Nelson, Summer J.; Pochron, Sharon T.; Semprebon, Gina M.; Godfrey, Laurie R.; Wright, Patricia C.; Jernvall, Jukka

2005-01-01

Primates tend to be long-lived, and, except for humans, most primate females are able to reproduce into old age. Although aging in most mammals is accompanied by dental senescence due to advanced wear, primates have low-crowned teeth that wear down before old age. Because tooth wear alters crown features gradually, testing whether early dental senescence causes reproductive senescence has been difficult. To identify whether and when low-crowned teeth compromise reproductive success, we used a 20-year field study of Propithecus edwardsi, a rainforest lemur from Madagascar with a maximum lifespan of >27 years. We analyzed tooth wear in three dimensions with dental topographic analysis by using Geographical Information Systems (GIS) technology. We report that tooth wear exposes compensatory shearing blades that maintain dental function for 18 years. Beyond this age, female fertility remains high; however infants survive only if lactation seasons have elevated rainfall. Therefore, low-crowned teeth accommodate wear to a point, after which reproductive success closely tracks environmental fluctuations. These results suggest a tooth wear-determined, but rainfall-mediated, onset of reproductive senescence. Additionally, our study indicates that even subtle changes in climate may affect reproductive success of rainforest species. PMID:16260727

Shape-from-shading using Landsat 8 and airborne laser altimetry over ice sheets: toward new regional DEMs of Greenland and Antarctica

NASA Astrophysics Data System (ADS)

Moussavi, M. S.; Scambos, T.; Haran, T. M.; Klinger, M. J.; Abdalati, W.

2015-12-01

We investigate the capability of Landsat 8's Operational Land Imager (OLI) instrument to quantify subtle ice sheet topography of Greenland and Antarctica. We use photoclinometry, or 'shape-from-shading', a method of deriving surface topography from local variations in image brightness due to varying surface slope. Photoclinomeetry is applicable over ice sheet areas with highly uniform albedo such as regions covered by recent snowfall. OLI imagery is available from both ascending and descending passes near the summer solstice period for both ice sheets. This provides two views of the surface features from two distinct solar azimuth illumination directions. Airborne laser altimetry data from the Airborne Topographic Mapper (ATM) instrument (flying on the Operation Ice Bridge program) are used to quantitatively convert the image brightness variations of surface undulations to surface slope. To validate the new DEM products, we use additional laser altimetry profiles collected over independent sites from Ice Bridge and ICESat, and high-resolution WorldView-2 DEMs. The photoclinometry-derived DEM products will be useful for studying surface elevation changes, enhancing bedrock elevation maps through inversion of surface topography, and inferring local variations in snow accumulation rates.

New implementation of a shear-force microscope suitable to study topographical features over wide areas

NASA Astrophysics Data System (ADS)

Ustione, A.; Cricenti, A.; Piacentini, M.; Felici, A. C.

2006-09-01

A new implementation of a shear-force microscope is described that uses a shear-force detection system to perform topographical imaging of large areas (˜1×1mm2). This implementation finds very interesting application in the study of archeological or artistic samples. Three dc motors are used to move a sample during a scan, allowing the probe tip to follow the surface and to face height differences of several tens of micrometers. This large-area topographical imaging mode exploits new subroutines that were added to the existing homemade software; these subroutines were created in Microsoft VISUAL BASIC 6.0 programming language. With this new feature our shear-force microscope can be used to study topographical details over large areas of archaeological samples in a nondestructive way. We show results detecting worn reliefs over a coin.

Biodiversity and Topographic Complexity: Modern and Geohistorical Perspectives

PubMed Central

Badgley, Catherine; Smiley, Tara M.; Terry, Rebecca; Davis, Edward B.; DeSantis, Larisa R.G.; Fox, David L.; Hopkins, Samantha S.B.; Jezkova, Tereza; Matocq, Marjorie D.; Matzke, Nick; McGuire, Jenny L.; Mulch, Andreas; Riddle, Brett R.; Roth, V. Louise; Samuels, Joshua X.; Strömberg, Caroline A.E.; Yanites, Brian J.

2018-01-01

Topographically complex regions on land and in the oceans feature hotspots of biodiversity that reflect geological influences on ecological and evolutionary processes. Over geologic time, topographic diversity gradients wax and wane over millions of years, tracking tectonic or climatic history. Topographic diversity gradients from the present day and the past can result from the generation of species by vicariance or from the accumulation of species from dispersal into a region with strong environmental gradients. Biological and geological approaches must be integrated to test alternative models of diversification along topographic gradients. Reciprocal illumination among phylogenetic, phylogeographic, ecological, paleontological, tectonic, and climatic perspectives is an emerging frontier of biogeographic research. PMID:28196688

Ambient seismic wave field

PubMed Central

NISHIDA, Kiwamu

2017-01-01

The ambient seismic wave field, also known as ambient noise, is excited by oceanic gravity waves primarily. This can be categorized as seismic hum (1–20 mHz), primary microseisms (0.02–0.1 Hz), and secondary microseisms (0.1–1 Hz). Below 20 mHz, pressure fluctuations of ocean infragravity waves reach the abyssal floor. Topographic coupling between seismic waves and ocean infragravity waves at the abyssal floor can explain the observed shear traction sources. Below 5 mHz, atmospheric disturbances may also contribute to this excitation. Excitation of primary microseisms can be attributed to topographic coupling between ocean swell and seismic waves on subtle undulation of continental shelves. Excitation of secondary microseisms can be attributed to non-linear forcing by standing ocean swell at the sea surface in both pelagic and coastal regions. Recent developments in source location based on body-wave microseisms enable us to estimate forcing quantitatively. For a comprehensive understanding, we must consider the solid Earth, the ocean, and the atmosphere as a coupled system. PMID:28769015

Revealing topographic lineaments through IHS enhancement of DEM data. [Digital Elevation Model

NASA Technical Reports Server (NTRS)

Murdock, Gary

1990-01-01

Intensity-hue-saturation (IHS) processing of slope (dip), aspect (dip direction), and elevation to reveal subtle topographic lineaments which may not be obvious in the unprocessed data are used to enhance digital elevation model (DEM) data from northwestern Nevada. This IHS method of lineament identification was applied to a mosiac of 12 square degrees using a Cray Y-MP8/864. Square arrays from 3 x 3 to 31 x 31 points were tested as well as several different slope enhancements. When relatively few points are used to fit the plane, lineaments of various lengths are observed and a mechanism for lineament classification is described. An area encompassing the gold deposits of the Carlin trend and including the Rain in the southeast to Midas in the northwest is investigated in greater detail. The orientation and density of lineaments may be determined on the gently sloping pediment surface as well as in the more steeply sloping ranges.

The Effects of Topographical Patterns and Sizes on Neural Stem Cell Behavior

PubMed Central

Qi, Lin; Li, Ning; Huang, Rong; Song, Qin; Wang, Long; Zhang, Qi; Su, Ruigong; Kong, Tao; Tang, Mingliang; Cheng, Guosheng

2013-01-01

Engineered topographical manipulation, a paralleling approach with conventional biochemical cues, has recently attracted the growing interests in utilizations to control stem cell fate. In this study, effects of topological parameters, pattern and size are emphasized on the proliferation and differentiation of adult neural stem cells (ANSCs). We fabricate micro-scale topographical Si wafers with two different feature sizes. These topographical patterns present linear micro-pattern (LMP), circular micro-pattern (CMP) and dot micro-pattern (DMP). The results show that the three topography substrates are suitable for ANSC growth, while they all depress ANSC proliferation when compared to non-patterned substrates (control). Meanwhile, LMP and CMP with two feature sizes can both significantly enhance ANSC differentiation to neurons compared to control. The smaller the feature size is, the better upregulation applies to ANSC for the differentiated neurons. The underlying mechanisms of topography-enhanced neuronal differentiation are further revealed by directing suppression of mitogen-activated protein kinase/extracellular signaling-regulated kinase (MAPK/Erk) signaling pathway in ANSC using U0126, known to inhibit the activation of Erk. The statistical results suggest MAPK/Erk pathway is partially involved in topography-induced differentiation. These observations provide a better understanding on the different roles of topographical cues on stem cell behavior, especially on the selective differentiation, and facilitate to advance the field of stem cell therapy. PMID:23527077

Cell adhesion on nanotextured slippery superhydrophobic substrates.

PubMed

Di Mundo, Rosa; Nardulli, Marina; Milella, Antonella; Favia, Pietro; d'Agostino, Riccardo; Gristina, Roberto

2011-04-19

In this work, the response of Saos2 cells to polymeric surfaces with different roughness/density of nanometric dots produced by a tailored plasma-etching process has been studied. Topographical features have been evaluated by atomic force microscopy, while wetting behavior, in terms of water-surface adhesion energy, has been evaluated by measurements of drop sliding angle. Saos2 cytocompatibility has been investigated by scanning electron microscopy, fluorescent microscopy, and optical microscopy. The similarity in outer chemical composition has allowed isolation of the impact of the topographical features on cellular behavior. The results indicate that Saos2 cells respond differently to surfaces with different nanoscale topographical features, clearly showing a certain inhibition in cell adhesion when the nanoscale is particularly small. This effect appears to be attenuated in surfaces with relatively bigger nanofeatures, though these express a more pronounced slippery/dry wetting character. © 2011 American Chemical Society

Biodiversity and Topographic Complexity: Modern and Geohistorical Perspectives.

PubMed

Badgley, Catherine; Smiley, Tara M; Terry, Rebecca; Davis, Edward B; DeSantis, Larisa R G; Fox, David L; Hopkins, Samantha S B; Jezkova, Tereza; Matocq, Marjorie D; Matzke, Nick; McGuire, Jenny L; Mulch, Andreas; Riddle, Brett R; Roth, V Louise; Samuels, Joshua X; Strömberg, Caroline A E; Yanites, Brian J

2017-03-01

Topographically complex regions on land and in the oceans feature hotspots of biodiversity that reflect geological influences on ecological and evolutionary processes. Over geologic time, topographic diversity gradients wax and wane over millions of years, tracking tectonic or climatic history. Topographic diversity gradients from the present day and the past can result from the generation of species by vicariance or from the accumulation of species from dispersal into a region with strong environmental gradients. Biological and geological approaches must be integrated to test alternative models of diversification along topographic gradients. Reciprocal illumination among phylogenetic, phylogeographic, ecological, paleontological, tectonic, and climatic perspectives is an emerging frontier of biogeographic research. Copyright © 2017 Elsevier Ltd. All rights reserved.

Multi-scale Visualization of Remote Sensing and Topographic Data of the Amazon Rain Forest for Environmental Monitoring of the Petroleum Industry.

NASA Astrophysics Data System (ADS)

Fonseca, L.; Miranda, F. P.; Beisl, C. H.; Souza-Fonseca, J.

2002-12-01

PETROBRAS (the Brazilian national oil company) built a pipeline to transport crude oil from the Urucu River region to a terminal in the vicinities of Coari, a city located in the right margin of the Solimoes River. The oil is then shipped by tankers to another terminal in Manaus, capital city of the Amazonas state. At the city of Coari, changes in water level between dry and wet seasons reach up to 14 meters. This strong seasonal character of the Amazonian climate gives rise to four distinct scenarios in the annual hydrological cycle: low water, high water, receding water, and rising water. These scenarios constitute the main reference for the definition of oil spill response planning in the region, since flooded forests and flooded vegetation are the most sensitive fluvial environments to oil spills. This study focuses on improving information about oil spill environmental sensitivity in Western Amazon by using 3D visualization techniques to help the analysis and interpretation of remote sensing and digital topographic data, as follows: (a) 1995 low flood and 1996 high flood JERS-1 SAR mosaics, band LHH, 100m pixel; (b) 2000 low flood and 2001 high flood RADARSAT-1 W1 images, band CHH, 30m pixel; (c) 2002 high flood airborne SAR images from the SIVAM project (System for Surveillance of the Amazon), band LHH, 3m pixel and band XHH, 6m pixel; (d) GTOPO30 digital elevation model, 30' resolution; (e) Digital elevation model derived from topographic information acquired during seismic surveys, 25m resolution; (f) panoramic views obtained from low altitude helicopter flights. The methodology applied includes image processing, cartographic conversion and generation of value-added product using 3D visualization. A semivariogram textural classification was applied to the SAR images in order to identify areas of flooded forest and flooded vegetation. The digital elevation models were color shaded to highlight subtle topographic features. Both datasets were then converted to the same cartographic projection and inserted into the Fledermaus 3D visualization environment. 3D visualization proved to be an important aid in understanding the spatial distribution pattern of the environmentally sensitive vegetation cover. The dynamics of the hydrological cycle was depicted in a basin-wide scale, revealing new geomorphic information relevant to assess the environmental risk of oil spills. Results demonstrate that pipelines constitute an environmentally saver option for oil transportation in the region when compared to fluvial tanker routes.

SRTM Colored Height and Shaded Relief: Near Zapala, Argentina

NASA Technical Reports Server (NTRS)

2001-01-01

Topographic data provided by the Shuttle Radar Topography Mission can provide many clues to geologic history and processes. This view of an area southwest of Zapala, Argentina, shows a wide diversity of geologic features. The highest peaks (left) appear to be massive (un-layered)crystalline rocks, perhaps granites. To their right (eastward) are tilted and eroded layered rocks, perhaps old lava flows, forming prominent ridges. Farther east and south, more subtle and curvilinear ridges show that the rock layers have not only been tilted but also folded. At the upper right, plateaus that cap the underlying geologic complexities are more recent lava flows - younger than the folding, but older than the current erosional pattern. Landforms in the southeast (lower right) and south-central areas appear partially wind sculpted.

Two visualization methods were combined to produce this image: shading and color coding of topographic height. The shade image was derived by computing topographic slope in the north-south direction. Northern slopes appear bright and southern slopes appear dark, as would be the case at noon at this latitude in the southern hemisphere. Color-coding is directly related to topographic height, with green at the lower elevations, rising through yellow, red, and magenta, to white at the highest elevations.

Elevation data used in this image were acquired by the Shuttle Radar Topography Mission aboard Space Shuttle Endeavour, launched on February 11,2000. The mission used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar that flew twice on Space Shuttle Endeavour in 1994. Shuttle Radar Topography Mission was designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration, the National Imagery and Mapping Agency of the U.S. Department of Defense, and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Earth Science Enterprise, Washington, DC.

Size: 45.9 by 36.0 kilometers ( 28.5 by 22.3 miles) Location: 39.4 deg. South lat., 70.3 deg. West lon. Orientation: North toward the top Image Data: Shaded and colored Shuttle Radar Topography Mission elevation model Date Acquired: February 2000

Digital Shaded-Relief Image of Alaska

USGS Publications Warehouse

Riehle, J.R.; Fleming, Michael D.; Molnia, B.F.; Dover, J.H.; Kelley, J.S.; Miller, M.L.; Nokleberg, W.J.; Plafker, George; Till, A.B.

1997-01-01

Introduction One of the most spectacular physiographic images of the conterminous United States, and the first to have been produced digitally, is that by Thelin and Pike (USGS I-2206, 1991). The image is remarkable for its crispness of detail and for the natural appearance of the artificial land surface. Our goal has been to produce a shaded-relief image of Alaska that has the same look and feel as the Thelin and Pike image. The Alaskan image could have been produced at the same scale as its lower 48 counterpart (1:3,500,000). But by insetting the Aleutian Islands into the Gulf of Alaska, we were able to print the Alaska map at a larger scale (1:2,500,000) and about the same physical size as the Thelin and Pike image. Benefits of the 1:2,500,000 scale are (1) greater resolution of topographic features and (2) ease of reference to the U.S. Geological Survey (USGS) (1987) Alaska Map E and the statewide geologic map (Beikman, 1980), which are both 1:2,500,000 scale. Manually drawn, shaded-relief images of Alaska's land surface have long been available (for example, Department of the Interior, 1909; Raisz, 1948). The topography depicted on these early maps is mainly schematic. Maps showing topographic contours were first available for the entire State in 1953 (USGS, 1:250,000) (J.H. Wittmann, USGS, written commun., 1996). The Alaska Map E was initially released in 1954 in both planimetric (revised in 1973 and 1987) and shaded-relief versions (revised in 1973, 1987, and 1996); topography depicted on the shaded-relief version is based on the 1:250,000-scale USGS topographic maps. Alaska Map E was later modified to include hypsometric tinting by Raven Maps and Images (1989, revised 1993) as copyrighted versions. Other shaded-relief images were produced for The National Geographic Magazine (LaGorce, 1956; 1:3,000,000) or drawn by Harrison (1970; 1:7,500,000) for The National Atlas of the United States. Recently, the State of Alaska digitally produced a shaded-relief image of Alaska at 1:2,500,000 scale (Alaska Department of Natural Resources, 1994), using the 1,000-m digital elevation data set referred to below. An important difference between our image and these previous ones is the method of reproduction: like the Thelin and Pike (1991) image, our image is a composite of halftone images that yields sharp resolution and preserves contrast. Indeed, the first impression of many viewers is that the Alaskan image and the Thelin and Pike image are composites of satellite-generated photographs rather than an artificial rendering of a digital elevation model. A shaded-relief image represents landforms in a natural fashion; that is, a viewer perceives the image as a rendering of reality. Thus a shaded-relief image is intrinsically appealing, especially in areas of spectacular relief. In addition, even subtle physiographic features that reflect geologic structures or the type of bedrock are visible. To our knowledge, some of these Alaskan features have not been depicted before and so the image should provide earth scientists with a new 'look' at fundamental geologic features of Alaska.

Vector Topographic Map Data over the BOREAS NSA and SSA in SIF Format

NASA Technical Reports Server (NTRS)

Knapp, David; Nickeson, Jaime; Hall, Forrest G. (Editor)

2000-01-01

This data set contains vector contours and other features of individual topographic map sheets from the National Topographic Series (NTS). The map sheet files were received in Standard Interchange Format (SIF) and cover the BOReal Ecosystem-Atmosphere Study (BOREAS) Northern Study Area (NSA) and Southern Study Area (SSA) at scales of 1:50,000 and 1:250,000. The individual files are stored in compressed Unix tar archives.

Topographic Maps and Coal Mining.

ERIC Educational Resources Information Center

Raitz, Karl B.

1984-01-01

Geography teachers can illustrate the patterns associated with mineral fuel production, especially coal, by using United States Geological Survey topographic maps, which are illustrated by symbols that indicate mine-related features, such as shafts and tailings. Map reading exercises are presented; an interpretative map key that can facilitate…

Delineating wetland catchments and modeling hydrologic connectivity using lidar data and aerial imagery

EPA Science Inventory

In traditional watershed delineation and topographic modeling, surface depressions are generally treated as spurious features and simply removed from a digital elevation model (DEM) to enforce flow continuity of water across the topographic surface to the watershed outlets. In re...

High-resolution multibeam mapping and submersible surveys of topographic features in the northwestern Gulf of Mexico

USGS Publications Warehouse

Hickerson, E.L.; Schmahl, G.P.; Weaver, D.C.; Gardner, J.V.

2003-01-01

The Flower Garden Banks National Marine Sanctuary (FGBNMS) and the USGS Pacific Seafloor Mapping Project mapped about 2000 km2 of the northwestern Gulf of Mexico continental shelf during June 2002, using a Kongsberg Simrad EM1000 multibeam echosounder. Mapping focused on select topographic highs thave hae been idetnnfied as biological features warranting protection from oil and gas activities by the Minerals Management Service (MMS). The base maps will be used for all future ROV and submersible missions.

Converting Topographic Maps into Digital Form to Aid in Archeological Research in the Peten, Guatemala

NASA Technical Reports Server (NTRS)

Aldrich, Serena R.

1999-01-01

The purpose of my project was to convert a topographical map into digital form so that the data can be manipulated and easily accessed in the field. With the data in this particular format, Dr. Sever and his colleagues can highlight the specific features of the landscape that they require for their research of the ancient Mayan civilization. Digital elevation models (DEMs) can also be created from the digitized contour features adding another dimension to their research.

Object-Oriented Image Clustering Method Using UAS Photogrammetric Imagery

NASA Astrophysics Data System (ADS)

Lin, Y.; Larson, A.; Schultz-Fellenz, E. S.; Sussman, A. J.; Swanson, E.; Coppersmith, R.

2016-12-01

Unmanned Aerial Systems (UAS) have been used widely as an imaging modality to obtain remotely sensed multi-band surface imagery, and are growing in popularity due to their efficiency, ease of use, and affordability. Los Alamos National Laboratory (LANL) has employed the use of UAS for geologic site characterization and change detection studies at a variety of field sites. The deployed UAS equipped with a standard visible band camera to collect imagery datasets. Based on the imagery collected, we use deep sparse algorithmic processing to detect and discriminate subtle topographic features created or impacted by subsurface activities. In this work, we develop an object-oriented remote sensing imagery clustering method for land cover classification. To improve the clustering and segmentation accuracy, instead of using conventional pixel-based clustering methods, we integrate the spatial information from neighboring regions to create super-pixels to avoid salt-and-pepper noise and subsequent over-segmentation. To further improve robustness of our clustering method, we also incorporate a custom digital elevation model (DEM) dataset generated using a structure-from-motion (SfM) algorithm together with the red, green, and blue (RGB) band data for clustering. In particular, we first employ an agglomerative clustering to create an initial segmentation map, from where every object is treated as a single (new) pixel. Based on the new pixels obtained, we generate new features to implement another level of clustering. We employ our clustering method to the RGB+DEM datasets collected at the field site. Through binary clustering and multi-object clustering tests, we verify that our method can accurately separate vegetation from non-vegetation regions, and are also able to differentiate object features on the surface.

Mapping ephemeral stream networks in desert environments using very-high-spatial-resolution multispectral remote sensing

DOE PAGES

Hamada, Yuki; O'Connor, Ben L.; Orr, Andrew B.; ...

2016-03-26

In this paper, understanding the spatial patterns of ephemeral streams is crucial for understanding how hydrologic processes influence the abundance and distribution of wildlife habitats in desert regions. Available methods for mapping ephemeral streams at the watershed scale typically underestimate the size of channel networks. Although remote sensing is an effective means of collecting data and obtaining information on large, inaccessible areas, conventional techniques for extracting channel features are not sufficient in regions that have small topographic gradients and subtle target-background spectral contrast. By using very high resolution multispectral imagery, we developed a new algorithm that applies landscape information tomore » map ephemeral channels in desert regions of the Southwestern United States where utility-scale solar energy development is occurring. Knowledge about landscape features and structures was integrated into the algorithm using a series of spectral transformation and spatial statistical operations to integrate information about landscape features and structures. The algorithm extracted ephemeral stream channels at a local scale, with the result that approximately 900% more ephemeral streams was identified than what were identified by using the U.S. Geological Survey’s National Hydrography Dataset. The accuracy of the algorithm in detecting channel areas was as high as 92%, and its accuracy in delineating channel center lines was 91% when compared to a subset of channel networks that were digitized by using the very high resolution imagery. Although the algorithm captured stream channels in desert landscapes across various channel sizes and forms, it often underestimated stream headwaters and channels obscured by bright soils and sparse vegetation. While further improvement is warranted, the algorithm provides an effective means of obtaining detailed information about ephemeral streams, and it could make a significant contribution toward improving the hydrological modelling of desert environments.« less

Mapping ephemeral stream networks in desert environments using very-high-spatial-resolution multispectral remote sensing

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

Hamada, Yuki; O'Connor, Ben L.; Orr, Andrew B.

In this paper, understanding the spatial patterns of ephemeral streams is crucial for understanding how hydrologic processes influence the abundance and distribution of wildlife habitats in desert regions. Available methods for mapping ephemeral streams at the watershed scale typically underestimate the size of channel networks. Although remote sensing is an effective means of collecting data and obtaining information on large, inaccessible areas, conventional techniques for extracting channel features are not sufficient in regions that have small topographic gradients and subtle target-background spectral contrast. By using very high resolution multispectral imagery, we developed a new algorithm that applies landscape information tomore » map ephemeral channels in desert regions of the Southwestern United States where utility-scale solar energy development is occurring. Knowledge about landscape features and structures was integrated into the algorithm using a series of spectral transformation and spatial statistical operations to integrate information about landscape features and structures. The algorithm extracted ephemeral stream channels at a local scale, with the result that approximately 900% more ephemeral streams was identified than what were identified by using the U.S. Geological Survey’s National Hydrography Dataset. The accuracy of the algorithm in detecting channel areas was as high as 92%, and its accuracy in delineating channel center lines was 91% when compared to a subset of channel networks that were digitized by using the very high resolution imagery. Although the algorithm captured stream channels in desert landscapes across various channel sizes and forms, it often underestimated stream headwaters and channels obscured by bright soils and sparse vegetation. While further improvement is warranted, the algorithm provides an effective means of obtaining detailed information about ephemeral streams, and it could make a significant contribution toward improving the hydrological modelling of desert environments.« less

Feature: Post Traumatic Stres Disorder PTSD: Symptoms, Diagnosis, Treatment

MedlinePlus

... Navigation Bar Home Current Issue Past Issues Feature PTSD Symptoms, Diagnosis , Treatment Past Issues / Winter 2009 Table ... Symptoms As with mild traumatic brain injury (TBI), PTSD symptoms can be very subtle. "For example, some ...

The design of superhydrophobic stainless steel surfaces by controlling nanostructures: A key parameter to reduce the implantation of pathogenic bacteria.

PubMed

Bruzaud, Jérôme; Tarrade, Jeanne; Celia, Elena; Darmanin, Thierry; Taffin de Givenchy, Elisabeth; Guittard, Frédéric; Herry, Jean-Marie; Guilbaud, Morgan; Bellon-Fontaine, Marie-Noëlle

2017-04-01

Reducing bacterial adhesion on substrates is fundamental for various industries. In this work, new superhydrophobic surfaces are created by electrodeposition of hydrophobic polymers (PEDOT-F 4 or PEDOT-H 8 ) on stainless steel with controlled topographical features, especially at a nano-scale. Results show that anti-bioadhesive and anti-biofilm properties require the control of the surface topographical features, and should be associated with a low adhesion of water onto the surface (Cassie-Baxter state) with limited crevice features at the scale of bacterial cells (nano-scale structures). Copyright © 2016. Published by Elsevier B.V.

Large-scale Topographical Screen for Investigation of Physical Neural-Guidance Cues

NASA Astrophysics Data System (ADS)

Li, Wei; Tang, Qing Yuan; Jadhav, Amol D.; Narang, Ankit; Qian, Wei Xian; Shi, Peng; Pang, Stella W.

2015-03-01

A combinatorial approach was used to present primary neurons with a large library of topographical features in the form of micropatterned substrate for high-throughput screening of physical neural-guidance cues that can effectively promote different aspects of neuronal development, including axon and dendritic outgrowth. Notably, the neuronal-guidance capability of specific features was automatically identified using a customized image processing software, thus significantly increasing the screening throughput with minimal subjective bias. Our results indicate that the anisotropic topographies promote axonal and in some cases dendritic extension relative to the isotropic topographies, while dendritic branching showed preference to plain substrates over the microscale features. The results from this work can be readily applied towards engineering novel biomaterials with precise surface topography that can serve as guidance conduits for neuro-regenerative applications. This novel topographical screening strategy combined with the automated processing capability can also be used for high-throughput screening of chemical or genetic regulatory factors in primary neurons.

Low-Amplitude Topographic Features and Textures on the Moon: Initial Results from Detrended Lunar Orbiter Laser Altimeter (LOLA) Topography

NASA Technical Reports Server (NTRS)

Kreslavsky, Mikhail A.; Head, James W.; Neumann, Gregory A.; Zuber, Maria T.; Smith, David E.

2016-01-01

Global lunar topographic data derived from ranging measurements by the Lunar Orbiter Laser Altimeter (LOLA) onboard LRO mission to the Moon have extremely high vertical precision. We use detrended topography as a means for utilization of this precision in geomorphological analysis. The detrended topography was calculated as a difference between actual topography and a trend surface defined as a median topography in a circular sliding window. We found that despite complicated distortions caused by the non-linear nature of the detrending procedure, visual inspection of these data facilitates identification of low-amplitude gently-sloping geomorphic features. We present specific examples of patterns of lava flows forming the lunar maria and revealing compound flow fields, a new class of lava flow complex on the Moon. We also highlight the identification of linear tectonic features that otherwise are obscured in the images and topographic data processed in a more traditional manner.

CFD Prediction on the Pressure Distribution and Streamlines around an Isolated Single-Storey House Considering the Effect of Topographic Characteristics

NASA Astrophysics Data System (ADS)

Abdullah, J.; Zaini, S. S.; Aziz, M. S. A.; Majid, T. A.; Deraman, S. N. C.; Yahya, W. N. W.

2018-04-01

Single-storey houses are classified as low rise building and vulnerable to damages under windstorm event. This study was carried out with the aim to investigate the pressure distribution and streamlines around an isolated house by considering the effect of terrain characteristics. The topographic features such as flat, depression, ridge, and valley, are considered in this study. This simulation were analysed with Ansys FLUENT 14.0 software package. The result showed the topography characteristics influence the value of pressure coefficient and streamlines especially when the house was located at ridge terrain. The findings strongly suggested that wind analysis should include all topographic features in the analysis in order to establish the true wind force exerted on any structure.

Spatial features register: toward standardization of spatial features

USGS Publications Warehouse

Cascio, Janette

1994-01-01

As the need to share spatial data increases, more than agreement on a common format is needed to ensure that the data is meaningful to both the importer and the exporter. Effective data transfer also requires common definitions of spatial features. To achieve this, part 2 of the Spatial Data Transfer Standard (SDTS) provides a model for a spatial features data content specification and a glossary of features and attributes that fit this model. The model provides a foundation for standardizing spatial features. The glossary now contains only a limited subset of hydrographic and topographic features. For it to be useful, terms and definitions must be included for other categories, such as base cartographic, bathymetric, cadastral, cultural and demographic, geodetic, geologic, ground transportation, international boundaries, soils, vegetation, water, and wetlands, and the set of hydrographic and topographic features must be expanded. This paper will review the philosophy of the SDTS part 2 and the current plans for creating a national spatial features register as one mechanism for maintaining part 2.

Quantitative topographic differentiation of the neonatal EEG.

PubMed

Paul, Karel; Krajca, Vladimír; Roth, Zdenek; Melichar, Jan; Petránek, Svojmil

2006-09-01

To test the discriminatory topographic potential of a new method of the automatic EEG analysis in neonates. A quantitative description of the neonatal EEG can contribute to the objective assessment of the functional state of the brain, and may improve the precision of diagnosing cerebral dysfunctions manifested by 'disorganization', 'dysrhythmia' or 'dysmaturity'. 21 healthy, full-term newborns were examined polygraphically during sleep (EEG-8 referential derivations, respiration, ECG, EOG, EMG). From each EEG record, two 5-min samples (one from the middle of quiet sleep, the other from the middle of active sleep) were subject to subsequent automatic analysis and were described by 13 variables: spectral features and features describing shape and variability of the signal. The data from individual infants were averaged and the number of variables was reduced by factor analysis. All factors identified by factor analysis were statistically significantly influenced by the location of derivation. A large number of statistically significant differences were also established when comparing the effects of individual derivations on each of the 13 measured variables. Both spectral features and features describing shape and variability of the signal are largely accountable for the topographic differentiation of the neonatal EEG. The presented method of the automatic EEG analysis is capable to assess the topographic characteristics of the neonatal EEG, and it is adequately sensitive and describes the neonatal electroencephalogram with sufficient precision. The discriminatory capability of the used method represents a promise for their application in the clinical practice.

Angiogenesis - a crucial step in breast cancer growth, progression and dissemination by Raman imaging

NASA Astrophysics Data System (ADS)

Kopeć, Monika; Abramczyk, Halina

2018-06-01

Combined micro-Raman imaging and AFM imaging are efficient methods for analyzing human tissue due to their high spatial and spectral resolution as well as sensitivity to subtle chemical, structural and topographical changes. The aim of this study was to determine biochemical composition and mechanical topography around blood vessels in the tumor mass of human breast tissue. Significant alterations of the chemical composition and structural architecture around the blood vessel were found compared to the normal breast tissue. A pronounced increase of collagen-fibroblast-glycocalyx network, as well as enhanced lactic acid, and glycogen activity in patients affected by breast cancer were reported.

A novel algorithm for delineating wetland depressions and mapping surface hydrologic flow pathways using LiDAR data

EPA Science Inventory

In traditional watershed delineation and topographic modeling, surface depressions are generally treated as spurious features and simply removed from a digital elevation model (DEM) to enforce flow continuity of water across the topographic surface to the watershed outlets. In re...

Delineation of Nested Wetland Catchments and Modeling of Hydrologic Connectivity Using LiDAR Data and Aerial Imagery

EPA Science Inventory

In traditional watershed delineation and topographic modelling, surface depressions are generally treated as spurious features and simply removed from a digital elevation model (DEM) to enforce flow continuity of water across the topographic surface to the watershed outlets. In r...

Seafloor Topographic Analysis in Staged Ocean Resource Exploration

NASA Astrophysics Data System (ADS)

Ikeda, M.; Okawa, M.; Osawa, K.; Kadoshima, K.; Asakawa, E.; Sumi, T.

2017-12-01

J-MARES (Research and Development Partnership for Next Generation Technology of Marine Resources Survey, JAPAN) has been designing a low-expense and high-efficiency exploration system for seafloor hydrothermal massive sulfide deposits in "Cross-ministerial Strategic Innovation Promotion Program (SIP)" granted by the Cabinet Office, Government of Japan since 2014. We designed a method to focus mineral deposit prospective area in multi-stages (the regional survey, semi-detail survey and detail survey) by extracted topographic features of some well-known seafloor massive sulfide deposits from seafloor topographic analysis using seafloor topographic data acquired by the bathymetric survey. We applied this procedure to an area of interest more than 100km x 100km over Okinawa Trough, including some known seafloor massive sulfide deposits. In Addition, we tried to create a three-dimensional model of seafloor topography by SfM (Structure from Motion) technique using multiple image data of Chimney distributed around well-known seafloor massive sulfide deposit taken with Hi-Vision camera mounted on ROV in detail survey such as geophysical exploration. Topographic features of Chimney was extracted by measuring created three-dimensional model. As the result, it was possible to estimate shape of seafloor sulfide such as Chimney to be mined by three-dimensional model created from image data taken with camera mounted on ROV. In this presentation, we will discuss about focusing mineral deposit prospective area in multi-stages by seafloor topographic analysis using seafloor topographic data in exploration system for seafloor massive sulfide deposit and also discuss about three-dimensional model of seafloor topography created from seafloor image data taken with ROV.

Laser-ranging scanning system to observe topographical deformations of volcanoes.

PubMed

Aoki, T; Takabe, M; Mizutani, K; Itabe, T

1997-02-20

We have developed a laser-ranging system to observe the topographical structure of volcanoes. This system can be used to measure the distance to a target by a laser and shows the three-dimensional topographical structure of a volcano with an accuracy of 30 cm. This accuracy is greater than that of a typical laser-ranging system that uses a corner-cube reflector as a target because the reflected light jitters as a result of inclination and unevenness of the target ground surface. However, this laser-ranging system is useful for detecting deformations of topographical features in which placement of a reflector is difficult, such as in volcanic regions.

Influence of different topographic correction strategies on mountain vegetation classification accuracy in the Lancang Watershed, China

NASA Astrophysics Data System (ADS)

Zhang, Zhiming; de Wulf, Robert R.; van Coillie, Frieke M. B.; Verbeke, Lieven P. C.; de Clercq, Eva M.; Ou, Xiaokun

2011-01-01

Mapping of vegetation using remote sensing in mountainous areas is considerably hampered by topographic effects on the spectral response pattern. A variety of topographic normalization techniques have been proposed to correct these illumination effects due to topography. The purpose of this study was to compare six different topographic normalization methods (Cosine correction, Minnaert correction, C-correction, Sun-canopy-sensor correction, two-stage topographic normalization, and slope matching technique) for their effectiveness in enhancing vegetation classification in mountainous environments. Since most of the vegetation classes in the rugged terrain of the Lancang Watershed (China) did not feature a normal distribution, artificial neural networks (ANNs) were employed as a classifier. Comparing the ANN classifications, none of the topographic correction methods could significantly improve ETM+ image classification overall accuracy. Nevertheless, at the class level, the accuracy of pine forest could be increased by using topographically corrected images. On the contrary, oak forest and mixed forest accuracies were significantly decreased by using corrected images. The results also showed that none of the topographic normalization strategies was satisfactorily able to correct for the topographic effects in severely shadowed areas.

Shaded relief, color as height Patagonia, Argentina

NASA Technical Reports Server (NTRS)

2000-01-01

This topographic image of Patagonia, Argentina shows a spectacular landscape formed by volcanoes, rivers, and wind. The area is located just east of the narrow range of the Andes Mountains, about 100 kilometers (62 miles) east of the border with Chile. Interesting features include basalt-capped mesas with sinkholes (lower center), arcuate ridges of windblown beach sands downwind from a salty desert lake (upper center), young volcanic cones(right), and at least one case of what geologists call 'inverted relief'. This happens when lava flows down a valley in soft material and then the soft material is eroded away leaving the former valley as a ridge of lava. These ridges can be seen on the slopes of the volcano in the upper right. Geologists will use SRTM topographic data to study the interaction of volcanic, climatic and erosional processes.

This shaded relief image was generated using topographic data from the Shuttle Radar Topography Mission. A computer-generated artificial light source illuminates the elevation data to produce a pattern of light and shadows. Slopes facing the light appear bright, while those facing away are shaded. On flatter surfaces, the pattern of light and shadows can reveal subtle features in the terrain. Colors show the elevation as measured by SRTM. Colors range from blue at the lowest elevations to white at the highest elevations. This image contains about 1100 meters(3600 feet) of total relief. White speckles on the face of some of the mountains are holes in the data caused by steep terrain. These will be filled using coverage from an intersecting pass.

The Shuttle Radar Topography Mission (SRTM), launched on February 11,2000, uses the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. The mission is designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, an additional C-band imaging antenna and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration (NASA), the National Imagery and Mapping Agency (NIMA) and the German (DLR) and Italian (ASI)space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Earth Science Enterprise, Washington, DC.

Size: 225 km (140 miles) x 170 km (105 miles) Location: 41 deg. South lat., 69 deg. West lon. Orientation: North toward upper right Original Data Resolution: 30 meters (99 feet) Date Acquired: February 19, 2000 Image: NASA/JPL/NIMA

Ground motion in the presence of complex Topography II: Earthquake sources and 3D simulations

USGS Publications Warehouse

Hartzell, Stephen; Ramirez-Guzman, Leonardo; Meremonte, Mark; Leeds, Alena L.

2017-01-01

Eight seismic stations were placed in a linear array with a topographic relief of 222 m over Mission Peak in the east San Francisco Bay region for a period of one year to study topographic effects. Seventy‐two well‐recorded local earthquakes are used to calculate spectral amplitude ratios relative to a reference site. A well‐defined fundamental resonance peak is observed with individual station amplitudes following the theoretically predicted progression of larger amplitudes in the upslope direction. Favored directions of vibration are also seen that are related to the trapping of shear waves within the primary ridge dimensions. Spectral peaks above the fundamental one are also related to topographic effects but follow a more complex pattern. Theoretical predictions using a 3D velocity model and accurate topography reproduce many of the general frequency and time‐domain features of the data. Shifts in spectral frequencies and amplitude differences, however, are related to deficiencies of the model and point out the importance of contributing factors, including the shear‐wave velocity under the topographic feature, near‐surface velocity gradients, and source parameters.

Venus' Chasmata and Earth's Spreading Centers: A Topographic Comparison

NASA Astrophysics Data System (ADS)

Stoddard, P. R.; Jurdy, D. M.

2008-12-01

Like the Earth, Venus has a global rift system, which has been cited as evidence of tectonic activity, despite the apparent lack of Earth-style plate tectonics. Both systems are marked by large ridges, usually with central grabens. On Earth, the topography of the rifts can be modeled well by a cooling half-space and the spreading of two divergent plates. The origin of the topographic signature on Venus, however, remains enigmatic. Venus' rift zones (termed "chasmata") can be fit by four great circle arcs extending 1000s of kilometers. The Venus chasmata system measures 54,464 km, which when corrected for the smaller size of the planet, nearly matches the 59,200-km total length of the spreading ridges determined for Earth. As on Earth, the chasmata with the greatest relief (7 km in just a 30-km run for Venus) represent the most recent tectonic activity. We use topographic profiles to look for well-understood terrestrial analogs to Venusian features. Focusing on mid-ocean ridge systems on Earth, we examine the variation along individual ridges, or rises, due to the gradual change in spreading rate (and thus cooling times). We then analyze the difference between fast and slow ridges, and propose that this technique may also be used to pick plate boundaries along spreading centers (SAM/AFR vs. NAM/AFR, e.g.). These profiles are then compared to those for Venus' rifts. Topographic profiles are based on the Magellan (Venus) and ETOPO5 (Earth) data sets. Long wavelength features appear similar to spreading systems on Earth, suggesting a deep, thermal cause. Short wavelength features, such as rift troughs and constructional edifices, are quite different, however, as expected from the vastly different surface conditions. Comparison of topographic profiles from Venus and Earth may lend insight into tectonic features and activity on our sister planet.

US Topo: topographic maps for the nation

USGS Publications Warehouse

Carswell, William J.

2013-01-01

US Topo is the next generation of topographic maps from the U.S. Geological Survey (USGS). Arranged in the familiar 7.5-minute quadrangle format, digital US Topo maps are designed to look and feel (and perform) like the traditional paper topographic maps for which the USGS is so well known. In contrast to paper-based maps, US Topo maps provide modern technical advantages that support faster, wider public distribution and enable basic, on-screen geographic analysis for all users. The US Topo quadrangle map has been redesigned so that map elements are visually distinguishable with the imagery turned on and off, while keeping the file size as small as possible. The US Topo map redesign includes improvements to various display factors, including symbol definitions (color, line thickness, line symbology, area fills), layer order, and annotation fonts. New features for 2013 include the following: a raster shaded relief layer, military boundaries, cemeteries and post offices, and a US Topo cartographic symbols legend as an attachment. US Topo quadrangle maps are available free on the Web. Each map quadrangle is constructed in GeoPDF® format using key layers of geographic data (orthoimagery, roads, geographic names, topographic contours, and hydrographic features) from The National Map databases. US Topo quadrangle maps can be printed from personal computers or plotters as complete, full-sized, maps or in customized sections, in a user-desired specific format. Paper copies of the maps can also be purchased from the USGS Store. Download links and a users guide are featured on the US Topo Web site. US Topo users can turn geographic data layers on and off as needed; they can zoom in and out to highlight specific features or see a broader area. File size for each digital 7.5-minute quadrangle, about 30 megabytes. Associated electronic tools for geographic analysis are available free for download. The US Topo provides the Nation with a topographic product that users can quickly incorporate into decisionmaking, operational or recreational activities.

Subtle evidence for paleoseismicity in the cratonic interior, U.S. A

NASA Astrophysics Data System (ADS)

Jacobson, W. Z.; Cowan, C. A.; Runkel, A. C.

2009-12-01

Intrastratal deformation features in Cambrian-Ordovician boundary strata in southeastern Minnesota, U.S.A., may be evidence for mid-continent paleoseismicity. Deformation features are present tens of kilometers east of the Midcontinent Rift zone, and include sand blows, water escape, and convolute lamination, as well as more subtle structures indicative of sand-on-sand density contrasts. The stratigraphic interval of interest is the uppermost Jordan Formation (Furongian), a very fine- to coarse-grained quartzose sandstone, and the basal Oneota Formation (Tremadocian), a heterolithic sandstone and dolostone that grades upward into bedded dolostone. Along the Jordan-Oneota boundary, deformation features are extensive, and the result of sand liquefaction and fluidization. Upward migration of excess pore water was obstructed in places by shale drapes that locally ruptured, causing sand to be injected into overlying beds. Movement of sand in this manner created voids that were filled by a chaotic mixture of sand, shale, and pebbles that collapsed from above. Where upwardly percolating water was not confined by shale, intrastratal flow produced water escape pillars. Other deformation features are present up to ~3 m below the Jordan-Oneota boundary, in well-sorted, pure quartzose sandstone. These features are inconspicuous because of the uniform texture and minerology of the sediment, and some were previously interpreted as synsedimentary phenomena. These features are common along foreset boundaries in large-scale (>3 m) cross-strata, and include cm-scale digitate interfaces (interfingering) and in situ rounded forms interpreted as sand-on-sand boudinage. They formed from density contrasts between individual foresets within the cross-bedded sand. The top of the lower foreset was less dense but more viscous than the base of the succeeding foreset. Such contrasts were the result of subtle packing and grain size differences formed during the avalanche process during dune migration. We interpret the trigger for deformation, however, to be a post-depositional (post-Oneota) event because of the association of these subtle features with the more obvious liquefaction features in the immediately overlying boundary strata (and the increased intensity of deformation along foresets upward toward the boundary). Although these features cannot be unambiguously attributed to a paleoseismic event, some other common possibilities can be eliminated, including slumping and loading by sediment, tides, and storm waves. These intrastratal deformation features are documented in one outcrop in southeastern Minnesota. The subtlety of some of these features suggests that similar features may have been overlooked in nearby outcrops. Indeed, we are now revisiting unusual features in some localities that we previously interpreted as synsedimentary phenomena. Seismites may be difficult to generate, and to recognize, in quartoze sandstones of the mid-continent due to the lack of significantly thick clay beds to serve as permeability barriers, and the homogenous textural and mineralogical attributes of these units.

Active Faulting, Earthquakes and Geomorphological Changes from Archaeoseismic Data and High-Resolution Topography: Effects on the Urban Evolution of the Roman Town of Sybaris, Ionian Sea (Southern Italy).

NASA Astrophysics Data System (ADS)

Alfonsi, L.; Brunori, C. A.; Cinti, F. R.

2014-12-01

The Sybaris town was founded by the Greeks in 720 B.C and its life went on up to the late Roman time (VI-VII century A.D.). The town was located within the Sibari Plain near the Crati River mouth (Ionian northern Calabria, southern Italy). Sybaris occurs in area repeatedly affected by natural damaging phenomena, as frequent flooding, high local subsidence, marine storms, and earthquakes. The 2700 year long record of history of Sybaris stores the traces of these natural events and their influence on the human ancient environment through time. Among the natural disasters, we recognize two Roman age earthquakes striking the town. We isolate the damaging of these seismic events, set their time of occurrence, and map a shear zone crossing the site. These results were obtained through i) survey of coseismic features on the ruins, ii) geoarchaeological stratigraphy analysis, and TL and C14 dating, iii) analysis of high-resolution topographic data (1m pixel LiDAR DEM). The Sybaris town showed a persistent resilience to the earthquakes, and following their occurrences the site was not abandoned but underwent remodeling of the urban topography. The interaction of the different approaches reveals the presence of a previously unknown fault crossing the archeological site, the Sybaris fault. The high-resolution topography allows the characterization of subtle geomorphological features and hydrological anomalies, tracing the fault extension, whose Holocene activity is controlling the local morphology and the present Crati river course.

Shaded Relief of South Africa, Northern Cape Province

NASA Technical Reports Server (NTRS)

2000-01-01

Located north of the Swartberg Mountains in South Africa's Northern Cape Province, this topographic image shows a portion of the Great Karoo region. Karoo is an indigenous word for 'dry thirst land.' The semi-arid area is known for its unique variety of flora and fauna. The topography of the area, with a total relief of 200 meters (650 feet), reveals much about the geologic history of the area. The linear features seen in the image are near-vertical walls of once-molten rock, or dikes, that have intruded the bedrock. The dikes are more resistant to weathering and, therefore, form the linear wall-like features seen in the image. In relatively flat arid areas such as this, small changes in the topography can have large impacts on the water resources and the local ecosystem. These data can be used by biologists to study the distribution and range of the different plants and animals. Geologists can also use the data to study the geologic history of this area in more detail.

This shaded relief image was generated using topographic data from the Shuttle Radar Topography Mission. A computer-generated artificial light source illuminates the elevation data to produce a pattern of light and shadows. Slopes facing the light appear bright, while those facing away are shaded. On flatter surfaces, the pattern of light and shadows can reveal subtle features in the terrain. Colors show the elevation as measured by SRTM. Colors range from green at the lowest elevations to reddish at the highest elevations. Shaded relief maps are commonly used in applications such as geologic mapping and land use planning.

The Shuttle Radar Topography Mission (SRTM), launched on February 11, 2000, uses the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. The mission is designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, an additional C-band imaging antenna and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration (NASA), the National Imagery and Mapping Agency (NIMA) and the German (DLR) and Italian (ASI) space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Earth Science Enterprise, Washington, DC.

US Topo: Topographic Maps for the Nation

USGS Publications Warehouse

Hytes, Patricia L.

2009-01-01

US Topo is the next generation of topographic maps from the U.S. Geological Survey (USGS). Arranged in the familiar 7.5-minute quadrangle format, digital US Topo maps are designed to look and feel (and perform) like the traditional paper topographic maps for which the USGS is so well known. In contrast to paper-based maps, US Topo maps provide modern technical advantages that support faster, wider public distribution and enable basic, on-screen geographic analysis for all users. US Topo maps are available free on the Web. Each map quadrangle is constructed in GeoPDF? format from key layers of geographic data (orthoimagery, roads, geographic names, topographic contours, and hydrographic features) found in The National Map. US Topo quadrangles can be printed from personal computers or plotters as complete, full-sized, maps or in customized sections, in a user-desired specific format. Paper copies of the maps can also be purchased from the USGS Store. Download links and a users guide are featured on the US Topo Web site. US Topo users can turn geographic data layers on and off as needed; they can zoom in and out to highlight specific features or see a broader area. File size for each digital 7.5-minute quadrangle, about 15-20 megabytes, is suitable for most users. Associated electronic tools for geographic analysis are available free for download.

Buried Craters In Isidis Planitia, Mars

NASA Astrophysics Data System (ADS)

Seabrook, A. M.; Rothery, D. A.; Wallis, D.; Bridges, J. C.; Wright, I. P.

We have produced a topographic map of Isidis Planitia, which includes the Beagle 2 landing site, using interpolated Mars Orbiter Laser Altimeter (MOLA) data from the Mars Global Surveyor (MGS) spacecraft currently orbiting Mars. MOLA data have a vertical precision of 37.5 cm, a footprint size of 130 m, an along-track shot spacing of 330 m, and an across-track spacing that is variable and may be several kilometres. This has revealed subtle topographic detail within the relatively smooth basin of Isidis Planitia. Analysis of this map shows apparent wrinkle ridges that could be the volcanic basement to the basin and also several circular depressions with diameters of several to tens of kilometres which we interpreted as buried impact craters, comparable to the so-called stealth craters recognised elsewhere in the northern lowlands of Mars[1]. Stealth craters are considered to be impact craters subjected to erosion and/or burial. Some of these features in Isidis have depressions that are on the order of tens metres lower than their rims and are very smooth, and so are often not visible in MGS Mars Orbiter Camera (MOC) or Viking images of the basin. The Isidis stealth craters are not restricted to the Hesperian Vastitas Borealis formations like those detected elsewhere in the northern lowlands by Kreslavsky and Head [1], but are also found in a younger Amazonian smooth plains unit. It is generally believed that Isidis Planitia has undergone one or more episodes of sedi- ment deposition, and so these buried craters most likely lie on an earlier surface, which could be the postulated volcanic basement to the basin. Analysis of the buried craters may give some understanding of the thickness, frequencies and ages of sedimentation episodes within the basin. This information will be important in developing a context in which information from the Beagle 2 lander can be analysed when it arrives on Mars in December 2003. [1] Kreslavsky M. A. and Head J. W. (2001) LPS XXXII

Quantification of shear stress in a meandering native topographic channel using a physical hydraulic model

Treesearch

Michael E. Ursic

2011-01-01

Current guidelines for predicting increases in shear stress in open-channel bends were developed from investigations that were primarily prismatic in cross section. This study provides possible increases in shear stress relative to approach flow conditions resulting from planimetric and topographic geometric features. Boundary shear stress estimates were determined by...

Elements of the Chicxulub Impact Structure as Revealed in SRTM and Surface GPS Topographic Data

NASA Technical Reports Server (NTRS)

Kinsland, Gary L.; Sanchez, Gary; Kobrick, Michael; Cardador, Manuel Hurtado

2003-01-01

Pope et al. [1] utilized the elevations from the Petroleos Mexicanos (PEMEX) gravity data files to show that the main component of the surface expression of the Chicxulub Impact Structure is a roughly semi-circular, lowrelief depression about 90 km in diameter. They also identified other topographic features and the elements of the buried impact, which possibly led to the development of these features. These are summarized in Table 1. Kinsland et al. [2] presented a connection between these topographic anomalies, small gravity anomalies and buried structure of the impact. Very recently we have acquired digital topography data from NASA s Shuttle Radar Topography Mission (SRTM). Our subset covers 6 square degrees from 20deg N 91degW to 22deg N 88degW (corner to corner) with a pixel size of about 90m. This area includes all of the identified portion of the crater on land.

Topographic Map of Chryse Planitia with Location of Possible Buried Basin

NASA Technical Reports Server (NTRS)

2005-01-01

This topographic map, based on data from the Mars Orbiter Laser Altimeter, shows the ground track of the 1,892nd and the 1,903rd orbits of Mars Express and the arc structures detected by that orbiter's Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS). The arc structures are interpreted to be part of a buried impact basin about 250 kilometers (155 miles) in diameter.

The topographic relief represented in the image is 1 kilometer (0.6 mile), from low (purple) to high (red). The projected arcs are shown in red for orbit 1892 and white for orbit 1903. There is no obvious feature in the surface topography that corresponds to the buried feature identified with MARSIS data.

NASA and the Italian Space Agency jointly funded the MARSIS instrument on the European Space Agency's Mars Express orbiter. The Mars Orbiter Laser Altimeter is an instrument on NASA's Mars Global Surveyor orbiter.

Angiogenesis - a crucial step in breast cancer growth, progression and dissemination by Raman imaging.

PubMed

Kopeć, Monika; Abramczyk, Halina

2018-06-05

Combined micro-Raman imaging and AFM imaging are efficient methods for analyzing human tissue due to their high spatial and spectral resolution as well as sensitivity to subtle chemical, structural and topographical changes. The aim of this study was to determine biochemical composition and mechanical topography around blood vessels in the tumor mass of human breast tissue. Significant alterations of the chemical composition and structural architecture around the blood vessel were found compared to the normal breast tissue. A pronounced increase of collagen-fibroblast-glycocalyx network, as well as enhanced lactic acid, and glycogen activity in patients affected by breast cancer were reported. Copyright © 2018 Elsevier B.V. All rights reserved.

Evaluation of solar angle variation over digital processing of LANDSAT imagery. [Brazil

NASA Technical Reports Server (NTRS)

Parada, N. D. J. (Principal Investigator); Novo, E. M. L. M.

1984-01-01

The effects of the seasonal variation of illumination over digital processing of LANDSAT images are evaluated. Original images are transformed by means of digital filtering to enhance their spatial features. The resulting images are used to obtain an unsupervised classification of relief units. After defining relief classes, which are supposed to be spectrally different, topographic variables (declivity, altitude, relief range and slope length) are used to identify the true relief units existing on the ground. The samples are also clustered by means of an unsupervised classification option. The results obtained for each LANDSAT overpass are compared. Digital processing is highly affected by illumination geometry. There is no correspondence between relief units as defined by spectral features and those resulting from topographic features.

Navigating neurites utilize cellular topography of Schwann cell somas and processes for optimal guidance

PubMed Central

Lopez-Fagundo, Cristina; Mitchel, Jennifer A.; Ramchal, Talisha D.; Dingle, Yu-Ting L.; Hoffman-Kim, Diane

2013-01-01

The path created by aligned Schwann cells (SCs) after nerve injury underlies peripheral nerve regeneration. We developed geometric bioinspired substrates to extract key information needed for axon guidance by deconstructing the topographical cues presented by SCs. We have previously reported materials that directly replicate SC topography with micro- and nanoscale resolution, but a detailed explanation of the means of directed axon extension on SC topography has not yet been described. Here, using neurite tracing and time-lapse microscopy, we analyzed the SC features that influence axon guidance. Novel poly(dimethylsiloxane) materials, fabricated via photolithography, incorporated bioinspired topographical components with the shapes and sizes of aligned SCs, namely somas and processes, where the length of the processes were varied but the soma geometry and dimensions were kept constant. Rat dorsal root ganglia neurites aligned to all materials presenting bioinspired topography after a 5 days in culture and to bioinspired materials presenting soma and process features after only 17 hours in culture. Key findings of this study were: Neurite response to underlying bioinspired topographical features was time dependent, where at 5 days, neurites aligned most strongly to materials presenting combinations of soma and process features, with higher than average density of either process or soma features; but at 17 hours they aligned more strongly to materials presenting average densities of soma and process features and to materials presenting process features only. These studies elucidate the influence of SC topography on axon guidance in a time-dependent setting and have implications for the optimization of nerve regeneration strategies. PMID:23557939

ToF-SIMS measurements with topographic information in combined images.

PubMed

Koch, Sabrina; Ziegler, Georg; Hutter, Herbert

2013-09-01

In 2D and 3D time-of-flight secondary ion mass spectrometric (ToF-SIMS) analysis, accentuated structures on the sample surface induce distorted element distributions in the measurement. The origin of this effect is the 45° incidence angle of the analysis beam, recording planar images with distortion of the sample surface. For the generation of correct element distributions, these artifacts associated with the sample surface need to be eliminated by measuring the sample surface topography and applying suitable algorithms. For this purpose, the next generation of ToF-SIMS instruments will feature a scanning probe microscope directly implemented in the sample chamber which allows the performance of topography measurements in situ. This work presents the combination of 2D and 3D ToF-SIMS analysis with topographic measurements by ex situ techniques such as atomic force microscopy (AFM), confocal microscopy (CM), and digital holographic microscopy (DHM). The concept of the combination of topographic and ToF-SIMS measurements in a single representation was applied to organic and inorganic samples featuring surface structures in the nanometer and micrometer ranges. The correct representation of planar and distorted ToF-SIMS images was achieved by the combination of topographic data with images of 2D as well as 3D ToF-SIMS measurements, using either AFM, CM, or DHM for the recording of topographic data.

Large Topographic Rises on Venus: Implications for Mantle Upwelling

NASA Technical Reports Server (NTRS)

Stofan, Ellen R.; Smrekar, Suzanne E.; Bindschandler, Duane L.; Senske, David A.

1995-01-01

Topographic rises on Venus have been identified that are interpreted to be the surface manifestation of mantle upwellings. These features are classified into groups based on their dominant morphology. Atla and Beta Regiones are classified as rift-dominated, Dione, western Eistla, Bell, and Imdr Regiones as volcano-dominated, and Themis, eastern Eistla, and central Eistla Regiones as corona-dominated. At several topographic rises, geologic indicators were identified that may provide evidence of uplifted topography (e.g., volcanic flow features trending upslope). We assessed the minimum contribution of volcanic construction to the topography of each rise, which in general represents less than 5% of the volume of the rise, similar to the volumes of edifices at terrestrial hotspot swells. The total melt volume at each rise is approximated to be 10(exp 4) - 10(exp 6) cu km. The variations in morphology, topography, and gravity signatures at topographic rises are not interpreted to indicate variations in stage of evolution of a mantle upwelling. Instead, the morphologic variations between the three classes of topographic rises are interpreted to indicate the varying influences of lithospheric structure, plume characteristics, and regional tectonic environment. Within each class, variations in topography, gravity, and amount of volcanism may be indicative of differing stages of evolution. The similarity between swell and volcanic volumes for terrestrial and Venusian hotspots implies comparable time-integrated plume strengths for individual upwellings on the two planets.

The dynamical control of subduction parameters on surface topography

NASA Astrophysics Data System (ADS)

Crameri, F.; Lithgow-Bertelloni, C. R.; Tackley, P. J.

2017-04-01

The long-wavelength surface deflection of Earth's outermost rocky shell is mainly controlled by large-scale dynamic processes like isostasy or mantle flow. The largest topographic amplitudes are therefore observed at plate boundaries due to the presence of large thermal heterogeneities and strong tectonic forces. Distinct vertical surface deflections are particularly apparent at convergent plate boundaries mostly due to the convergence and asymmetric sinking of the plates. Having a mantle convection model with a free surface that is able to reproduce both realistic single-sided subduction and long-wavelength surface topography self-consistently, we are now able to better investigate this interaction. We separate the topographic signal into distinct features and quantify the individual topographic contribution of several controlling subduction parameters. Results are diagnosed by splitting the topographic signal into isostatic and residual components, and by considering various physical aspects like viscous dissipation during plate bending. Performing several systematic suites of experiments, we are then able to quantify the topographic impact of the buoyancy, rheology, and geometry of the subduction-zone system to each and every topographic feature at a subduction zone and to provide corresponding scaling laws. We identify slab dip and, slightly less importantly, slab buoyancy as the major agents controlling surface topography at subduction zones on Earth. Only the island-arc high and the back-arc depression extent are mainly controlled by plate strength. Overall, his modeling study sets the basis to better constrain deep-seated mantle structures and their physical properties via the observed surface topography on present-day Earth and back through time.

Landslides Identification Using Airborne Laser Scanning Data Derived Topographic Terrain Attributes and Support Vector Machine Classification

NASA Astrophysics Data System (ADS)

Pawłuszek, Kamila; Borkowski, Andrzej

2016-06-01

Since the availability of high-resolution Airborne Laser Scanning (ALS) data, substantial progress in geomorphological research, especially in landslide analysis, has been carried out. First and second order derivatives of Digital Terrain Model (DTM) have become a popular and powerful tool in landslide inventory mapping. Nevertheless, an automatic landslide mapping based on sophisticated classifiers including Support Vector Machine (SVM), Artificial Neural Network or Random Forests is often computationally time consuming. The objective of this research is to deeply explore topographic information provided by ALS data and overcome computational time limitation. For this reason, an extended set of topographic features and the Principal Component Analysis (PCA) were used to reduce redundant information. The proposed novel approach was tested on a susceptible area affected by more than 50 landslides located on Rożnów Lake in Carpathian Mountains, Poland. The initial seven PCA components with 90% of the total variability in the original topographic attributes were used for SVM classification. Comparing results with landslide inventory map, the average user's accuracy (UA), producer's accuracy (PA), and overall accuracy (OA) were calculated for two models according to the classification results. Thereby, for the PCA-feature-reduced model UA, PA, and OA were found to be 72%, 76%, and 72%, respectively. Similarly, UA, PA, and OA in the non-reduced original topographic model, was 74%, 77% and 74%, respectively. Using the initial seven PCA components instead of the twenty original topographic attributes does not significantly change identification accuracy but reduce computational time.

Fine resolution topographic mapping of the Jovian moons: a Ka-band high resolution topographic mapping interferometric synthetic aperture radar

NASA Technical Reports Server (NTRS)

Madsen, Soren N.; Carsey, Frank D.; Turtle, Elizabeth P.

2003-01-01

The topographic data set obtained by MOLA has provided an unprecedented level of information about Mars' geologic features. The proposed flight of JIMO provides an opportunity to accomplish a similar mapping of and comparable scientific discovery for the Jovian moons through us of an interferometric imaging radar analogous to the Shuttle radar that recently generated a new topographic map of Earth. A Ka-band single pass across-track synthetic aperture radar (SAR) interferometer can provide very high resolution surface elevation maps. The concept would use two antennas mounted at the ends of a deployable boom (similar to the Shuttle Radar Topographic Mapper) extended orthogonal to the direction of flight. Assuming an orbit altitude of approximately 100 km and a ground velocity of approximately 1.5 km/sec, horizontal resolutions at the 10 meter level and vertical resolutions at the sub-meter level are possible.

Fine Resolution Topographic Mapping of the Jovian Moons: A Ka-Band High Resolution Topographic Mapping Interferometric Synthetic Aperture Radar

NASA Technical Reports Server (NTRS)

Madsen, S. N.; Carsey, F. D.; Turtle, E. P.

2003-01-01

The topographic data set obtained by MOLA has provided an unprecedented level of information about Mars' geologic features. The proposed flight of JIMO provides an opportunity to accomplish a similar mapping of and comparable scientific discovery for the Jovian moons through use of an interferometric imaging radar analogous to the Shuttle radar that recently generated a new topographic map of Earth. A Ka-band single pass across-track synthetic aperture radar (SAR) interferometer can provide very high resolution surface elevation maps. The concept would use two antennas mounted at the ends of a deployable boom (similar to the Shuttle Radar Topographic Mapper) extended orthogonal to the direction of flight. Assuming an orbit altitude of approximately 100km and a ground velocity of approximately 1.5 km/sec, horizontal resolutions at the 10 meter level and vertical resolutions at the sub-meter level are possible.

Quantitative topographic analysis as a guide to rover-based research on Mars

NASA Astrophysics Data System (ADS)

Palucis, M. C.; Dietrich, W. E.; Parker, T. J.; Sumner, D. Y.; Williams, R. M. E.; Hayes, A.; Mangold, N.; Lewis, K. W.

2014-12-01

Satellite imagery of Mars now provides remarkable topographic data, often better than that on Earth in many countries. For decades, researchers have identified landforms on Mars that indicated the presence of gullies, rivers, deltas, fans, and lakes, pointing to the presence of surface waters, and the apparent necessity of an active hydrologic cycle involving rain or snow. Quantitative topographic analysis has provided a means to estimate volumes of runoff, sediment transport rates, and peak flow discharges, first using orbital imagery alone and then using laser altimetery coverage and higher resolution HiRISE (1 m/px), CTX (20 m/px) and HRSC (50 m/px) topography. Our detailed topographic analysis of the Peace Vallis fan near the Curiosity rover landing site in Gale Crater (Mars) suggested that the fan entered into a pre-existing enclosed basin that would likely contain lake sediments; sedimentary, mineralogical, and chemical analysis of this region, now named Yellowknife Bay, later found this to be the case, though debate remains on the exact origin and history of the deposit. The rover is currently heading to a 5 km high sedimentary mound (Aeolis Mons) with mineral signatures hypothesized to be the result of planet-wide changes in climate. Topographic features on the mound, which correspond in elevation with other large depositional features around the crater, suggest that a succession of lakes developed post-Noachian. Within Gale, we are in a unique position to determine the extent at which topography can tell us the evolutionary history of a place on another planet, since our hypotheses can actually be tested as the Curiosity rover makes its ascent up Aeolis Mons. Along the rover's traverse, we propose based on the geomorphic record that the sediments being examined were water soaked, perhaps several times under deep lakes, and that the rover will cross shorelines that may not be well-preserved, but are worth searching for. A quantitative topographic analysis of the fan and delta features and their source areas on the crater wall and Aeolis Mons suggest that mass is conserved, hence these features have experienced little modification since emplacement, but this also presents challenges for explaining the origin of the coarse sedimentary deposits Curiosity has recently encountered.

Fractal based modelling and analysis of electromyography (EMG) to identify subtle actions.

PubMed

Arjunan, Sridhar P; Kumar, Dinesh K

2007-01-01

The paper reports the use of fractal theory and fractal dimension to study the non-linear properties of surface electromyogram (sEMG) and to use these properties to classify subtle hand actions. The paper reports identifying a new feature of the fractal dimension, the bias that has been found to be useful in modelling the muscle activity and of sEMG. Experimental results demonstrate that the feature set consisting of bias values and fractal dimension of the recordings is suitable for classification of sEMG against the different hand gestures. The scatter plots demonstrate the presence of simple relationships of these features against the four hand gestures. The results indicate that there is small inter-experimental variation but large inter-subject variation. This may be due to differences in the size and shape of muscles for different subjects. The possible applications of this research include use in developing prosthetic hands, controlling machines and computers.

Volunteer map data collection at the USGS

USGS Publications Warehouse

Eric, B. Wolf; Poore, Barbara S.; Caro, Holly K.; Matthews, Greg D.

2011-01-01

Since 1994, citizen volunteers have helped the U.S. Geological Survey (USGS) improve its topographic maps. Through the Earth Science Corps program, citizens were able to "adopt a quad" and collect new information and update existing map features. Until its conclusion in 2001, as many as 300 volunteers annotated paper maps which were incorporated into the USGS topographic-map revision process.

The Nucleus of Comet 9P-Tempel 1: Shape and Geology from Two Flybys

NASA Technical Reports Server (NTRS)

Thomas, P.; A'Hearn, M.; Belton, M. J. S.; Brownlee, D.; Carcich, B.; Hermalyn, B.; Klaasen, K.; Sackett, S.; Schultz, P. H.; Veverka, J.;

The 20th-Century Topographic Survey as Source Data for Long-Term Landscape Studies at Local and Regional Scales

USGS Publications Warehouse

Varanka, Dalia

2006-01-01

Historical topographic maps are the only systematically collected data resource covering the entire nation for long-term landscape change studies over the 20th century for geographical and environmental research. The paper discusses aspects of the historical U.S. Geological Survey topographic maps that present constraints on the design of a database for such studies. Problems involved in this approach include locating the required maps, understanding land feature classification differences between topographic vs. land use/land cover maps, the approximation of error between different map editions of the same area, and the identification of true changes on the landscape between time periods. Suggested approaches to these issues are illustrated using an example of such a study by the author.

Possible climate-related signals in high-resolution topography of lobate debris aprons in Tempe Terra, Mars

NASA Astrophysics Data System (ADS)

Grindrod, Peter M.; Fawcett, Stephen A.

2011-10-01

Lobate debris aprons are common features in the mid-latitudes of Mars that are assumed to be the result of the flow of ice-rich material. We produce high-resolution digital elevation models of two of these features in the Tempe Terra region of Mars using HiRISE stereo images. We identify two main topographic features of different wavelength using a power spectrum analysis approach. Short wavelength features, between approximately 10 and 20 m in length, correspond to a polygonal surface texture present throughout our study area. Long wavelength features, between approximately 700 and 1800 m in length, correspond to broad ridges that are up to 20 m in amplitude. We interpret both topographic signals to be the likely result of climate change affecting the debris contribution and/or the flow regime of the lobate debris aprons. The apparent surface age of about 300 Ma could be evidence of an astronomical forcing mechanism recorded in these lobate debris aprons at this time in Mars' history.

Visualizing cell extracellular matrix (ECM) deposited by cells cultured on aligned bacteriophage M13 thin films.

PubMed

Wu, Laying; Lee, L Andrew; Niu, Zhongwei; Ghoshroy, Soumitra; Wang, Qian

2011-08-02

Topographical features ranging from micro- to nanometers can affect cell orientation and migratory pathways, which are important factors in tissue engineering and tumor migration. In our previous study, a convective assembly of bacteriophage M13 resulted in thin films which could be used to control the alignment of cells. However, several questions regarding its underlying reasons to dictate cell alignment remained unanswered. Here, we further study the nanometer topographical features generated by the bacteriophage M13 crystalline film, which results in the alignment of the cells and extracellular matrix (ECM) proteins. Sequential imaging analyses at micro- and nanoscale levels of aligned cells and fibrillar matrix proteins were documented using scanning electron microscopy and immunofluorescence microscopy. As a result, we observed baby hamster kidney cells with higher degree of alignment on the ordered M13 substrates than NIH-3T3 fibroblasts, a difference which could be attributed to the intrinsic nature of the cells' production of ECM proteins. The results from this study provide a crucial insight into the topographical features of a biological thin film, which can be utilized to control the orientation of cells and surrounding ECM proteins.

South San Francisco Bay 2004 topographic lidar survey: Data overview and preliminary quality assessment

USGS Publications Warehouse

Foxgrover, Amy C.; Jaffe, Bruce E.

2005-01-01

This report details the collection of lidar in South Bay, the ground-truthing efforts, preliminary accuracy assessments, and known limitations of the data set. We describe the data generated from the survey and how to obtain it. In addition, we present maps and sample imagery that provides a revealing look into the intricate topographic features of South Bay.

Invisible Colors of the Moon

NASA Image and Video Library

2009-09-24

Data from NASA Moon Mineralogy Mapper instrument on the Indian Space Research Organization Chandrayaan-1 spacecraft reveal subtle and previously unknown lunar diversity and features. Animation available at the Photojournal.

Application of PALSAR-2 Remote Sensing Data for Landslide Hazard Mapping in Kelantan River Basin, Peninsular Malaysia

NASA Astrophysics Data System (ADS)

Beiranvand Pour, Amin; Hashim, Mazlan

2016-06-01

Yearly, several landslides ensued during heavy monsoons rainfall in Kelantan river basin, peninsular Malaysia, which are obviously connected to geological structures and topographical features of the region. In this study, the recently launched Phased Array type L-band Synthetic Aperture Radar-2 (PALSAR-2) onboard the Advanced Land Observing Satellite-2 (ALOS-2), remote sensing data were used to map geological structural and topographical features in the Kelantan river basin for identification of high potential risk and susceptible zones for landslides. Adaptive Local Sigma filter was selected and applied to accomplish speckle reduction and preserving both edges and features in PALSAR-2 fine mode observation images. Different polarization images were integrated to enhance geological structures. Additionally, directional filters were applied to the PALSAR-2 Local Sigma resultant image for edge enhancement and detailed identification of linear features. Several faults, drainage patterns and lithological contact layers were identified at regional scale. In order to assess the results, fieldwork and GPS survey were conducted in the landslide affected zones in the Kelantan river basin. Results demonstrate the most of the landslides were associated with N-S, NNW-SSE and NE-SW trending faults, angulated drainage pattern and metamorphic and Quaternary units. Consequently, structural and topographical geology maps were produced for Kelantan river basin using PALSAR-2 data, which could be broadly applicable for landslide hazard mapping.

Microtopographic characterization of ice-wedge polygon landscape in Barrow, Alaska: a digital map of troughs, rims, centers derived from high resolution (0.25 m) LiDAR data

DOE Data Explorer

Gangodagamage, Chandana; Wullschleger, Stan

2014-07-03

The dataset represents microtopographic characterization of the ice-wedge polygon landscape in Barrow, Alaska. Three microtopographic features are delineated using 0.25 m high resolution digital elevation dataset derived from LiDAR. The troughs, rims, and centers are the three categories in this classification scheme. The polygon troughs are the surface expression of the ice-wedges that are in lower elevations than the interior polygon. The elevated shoulders of the polygon interior immediately adjacent to the polygon troughs are the polygon rims for the low center polygons. In case of high center polygons, these features are the topographic highs. In this classification scheme, both topographic highs and rims are considered as polygon rims. The next version of the dataset will include more refined classification scheme including separate classes for rims ad topographic highs. The interior part of the polygon just adjacent to the polygon rims are the polygon centers.

The Design and Product of National 1:1000000 Cartographic Data of Topographic Map

NASA Astrophysics Data System (ADS)

Wang, Guizhi

2016-06-01

National administration of surveying, mapping and geoinformation started to launch the project of national fundamental geographic information database dynamic update in 2012. Among them, the 1:50000 database was updated once a year, furthermore the 1:250000 database was downsized and linkage-updated on the basis. In 2014, using the latest achievements of 1:250000 database, comprehensively update the 1:1000000 digital line graph database. At the same time, generate cartographic data of topographic map and digital elevation model data. This article mainly introduce national 1:1000000 cartographic data of topographic map, include feature content, database structure, Database-driven Mapping technology, workflow and so on.

Exhumation and topographic evolution of the Namche Barwa Syntaxis, eastern Himalaya

NASA Astrophysics Data System (ADS)

Yang, Rong; Herman, Frédéric; Fellin, Maria Giuditta; Maden, Colin

2018-01-01

The Namche Barwa Syntaxis, as one of the most tectonically active regions, remains an appropriate place to explore the relationship between tectonics, surface processes, and landscape evolution. Two leading models have been proposed for the formation and evolution of this syntaxis, including the tectonic aneurysm model and the syntaxis expansion model. Here we use a multi-disciplinary approach based on low-temperature thermochronometry, numerical modeling, river profile and topographic analyses to investigate the interactions between tectonics, erosion, and landscape evolution and to test these models. Our results emphasize the presence of young cooling ages (i.e., < 1 Ma) along the Parlung River, to the north of the syntaxis. Using numerical modeling we argue that a recent increase in exhumation rate is required to expose these young ages. Our river analysis reveals spatial variations in channel steepness, which we interpret to reflect the rock uplift pattern. By establishing the relationship between erosion rates and topographic features, we find that erosion rates are poorly to weakly correlated with topographic features, suggesting that the landscape is still evolving. Altogether, these results seem better explained by a mechanism that involves a northward expansion of the syntaxis, which causes high rock uplift rates to the north of the syntaxis and a transient state of topography adjusting to an evolving tectonic setting.

Topographic precursors and geological structures of deep-seated catastrophic landslides caused by typhoon Talas, determined from the analysis of high-resolution DEMs

NASA Astrophysics Data System (ADS)

Chigira, Masahiro; Tsou, Ching-Ying; Matsushi, Yuki

2013-04-01

Typhoon Talas crossed the Japanese Islands between 2 and 5 September 2011, causing more than 70 deep-seated catastrophic landslides in a Jurassic to Paleogene-Early Miocene accretion complex. Detailed examination of the topographic features of 10 large landslides before the event, recorded on DEMs with a resolution of 1 m (based on airborne laser scanner surveys), showed that all of the landslides had small scarplets near their future crowns prior to the slide, and one landslide had linear depressions along its future crown as precursor topographic features. These scarplets and linear depressions were caused by gravitational slope deformation that preceded the catastrophic failure. Strains, defined by the ratio of the length of a scarplet to the length of the whole slope (as measured along the slope line), ranged from 5% to 21%, and are the first reliable numerical data relating to the topographic precursor features of large and catastrophic landslides. Careful examination of aerial photographs from another four large landslides, for which no high-resolution DEMs were available, suggested that they also developed scarplets at their heads beforehand, which are not precisely quantified. Twelve of the 14 landslides we surveyed in the field had sliding surfaces with wedge-shaped discontinuities that consisted of faults, shear surfaces that formed during accretion, and bedding, suggesting that the buildup of pore pressure occurs readily in a gravitationally deformed rock body containing wedge-shaped discontinuities. Other types of gravitational deformation were also active; e.g., flexural toppling and buckling were each observed to have preceded one landslide.

Subtle Sex-Role Cues in Children's Commercials.

ERIC Educational Resources Information Center

And Others; Welch, Renate L.

1979-01-01

Examines forms of communication used in commercials to convey social stereotypes. (Forms refer to production techniques such as level of action or movement, pacing, camera techniques, and auditory features.) (PD)

Detection of subtle nocturnal motor activity from 3-D accelerometry recordings in epilepsy patients.

PubMed

Nijsen, Tamara M E; Cluitmans, Pierre J M; Arends, Johan B A M; Griep, Paul A M

2007-11-01

This paper presents a first step towards reliable detection of nocturnal epileptic seizures based on 3-D accelerometry (ACM) recordings. The main goal is to distinguish between data with and without subtle nocturnal motor activity, thus reducing the amount of data that needs further (more complex) analysis for seizure detection. From 15 ACM signals (measured on five positions on the body), two features are computed, the variance and the jerk. In the resulting 2-D feature space, a linear threshold function is used for classification. For training and testing, the algorithm ACM data along with video data is used from nocturnal registrations in seven mentally retarded patients with severe epilepsy. Per patient, the algorithm detected 100% of the periods of motor activity that are marked in video recordings and the ACM signals by experts. From all the detections, 43%-89% was correct (mean =65%). We were able to reduce the amount of data that need to be analyzed considerably. The results show that our approach can be used for detection of subtle nocturnal motor activity. Furthermore, our results indicate that our algorithm is robust for fluctuations across patients. Consequently, there is no need for training the algorithm for each new patient.

Precision Topography of Pluvial Features in Nevada as Analogs for Possible Pluvial Landforms on Mars

NASA Astrophysics Data System (ADS)

Zimbelman, J. R.; Garry, W. B.; Irwin, R. P.

2009-12-01

Topographic measurements with better than 2 cm horizontal and 4 cm vertical precision were obtained for pluvial features in Nevada using a Trimble R8 Differential Global Positioning System (DGPS), making use of both real-time kinematic and post-processed kinematic techniques. We collected ten transects across shorelines in the southern end of Surprise Valley, near the California border in NW Nevada, on April 15-17, 2008, plus five transects of shorelines and eight transects of a wavecut scarp in Long Valley, near the Utah border in NE Nevada, on May 5-7, 2009. Each transect consists of topographic points keyed to field notes and photographs. In Surprise Valley, the highstand shoreline was noted at 1533.4 m elevation in 8 of the 10 transects, and several prominent intermediate shorelines could be correlated between two or more transects. In Long Valley, the well preserved highstand shoreline elevation of 1908.7 m correlated (within 0.6 m) to the base of the wavecut scarp along a horizontal distance of 1.2 km. These results demonstrate that adherence to a geopotential elevation level is one of the strongest indicators that a possible shoreline feature is the result of pluvial processes, and that elevation levels of features can be clearly detected and documented with precise topographic measurements. The High Resolution Imaging Science Experiment (HiRISE) is returning images of Mars that show potential shoreline features in remarkable detail (e.g., image PSP_009998_2165, 32 cm/pixel, showing a possible shoreline in NW Arabia). Our results from studying shorelines in Nevada will provide a basis for evaluating the plausibility of possible shoreline features on Mars, the implications of which are significant for the overall history of Mars.

Report on the ALPO LTP observing program. [for establishing albedo scale for lunar features

NASA Technical Reports Server (NTRS)

Cameron, W. S.

1974-01-01

Observations of lunar transient phenomena for the Association of Lunar and Planetary Observers (ALPO) are reported. The procedures for making visual observations for estimating albedo are described, and the reported albedo analyzed for lunar topographic features. It is shown that a catalog or scale of albedos can be established for each feature.

Fast synthesis of topographic mask effects based on rigorous solutions

NASA Astrophysics Data System (ADS)

Yan, Qiliang; Deng, Zhijie; Shiely, James

2007-10-01

Topographic mask effects can no longer be ignored at technology nodes of 45 nm, 32 nm and beyond. As feature sizes become comparable to the mask topographic dimensions and the exposure wavelength, the popular thin mask model breaks down, because the mask transmission no longer follows the layout. A reliable mask transmission function has to be derived from Maxwell equations. Unfortunately, rigorous solutions of Maxwell equations are only manageable for limited field sizes, but impractical for full-chip optical proximity corrections (OPC) due to the prohibitive runtime. Approximation algorithms are in demand to achieve a balance between acceptable computation time and tolerable errors. In this paper, a fast algorithm is proposed and demonstrated to model topographic mask effects for OPC applications. The ProGen Topographic Mask (POTOMAC) model synthesizes the mask transmission functions out of small-sized Maxwell solutions from a finite-difference-in-time-domain (FDTD) engine, an industry leading rigorous simulator of topographic mask effect from SOLID-E. The integral framework presents a seamless solution to the end user. Preliminary results indicate the overhead introduced by POTOMAC is contained within the same order of magnitude in comparison to the thin mask approach.

Identifying suitable land for alternative crops in a drying climate: soil salinity, texture and topographic conditions for the growth of old man saltbush (Atriplex nummularia)

NASA Astrophysics Data System (ADS)

Holmes, K. W.; Barrett-Lennard, E. G.; Altman, M.

2011-12-01

Experiments conducted under controlled conditions clearly show that the growth and survival of plants on saltland is affected by both the levels of salinity and waterlogging (or depth to water-table) in the soil. Different plant species thrive under varying combinations of these growth constraints. However in natural settings, short distance spatial variability in soil properties and subtle topographic features often complicate the definition of saline and soil hydrological conditions; additional factors may also overprint the trends identified under controlled conditions, making it difficult to define the physical settings where planting is economically viable. We investigated the establishment and growth of old man saltbush (Atriplex nummularia) in relation to variable soil-landscape conditions across an experimental site in southwestern Australia where the combination of high salinity and occasional seasonal waterlogging ruled out the growth of traditional crops and pastures. Saltbush can be critical supplemental feed in the dry season, providing essential nutrients for sheep in combination with sufficient water and dry feed (hay). We applied a range of modeling approaches including classification and regression trees and generalized linear models to statistically characterize these plant-environment relationships, and extend them spatially using full cover raster covariate datasets. Plant deaths could be consistently predicted (97% correct classification of independent dataset) using a combination of topographic variables, salinity, soil mineralogical information, and depth to the water table. Plant growth patterns were more difficult to predict, particularly after several years of grazing, however variation in plant volume was well-explained with a linear model (r2 = 0.6, P < 0.0001). All types of environmental data were required, supporting the starting hypothesis that saltland pasture success is driven by water movement in the landscape. The final selected covariates for modeling were a digital elevation model and derivatives, soil mineralogy, competitors for water (adjacent trees) and soil salinity (measured with an EM38). Our exploration of strengths and weaknesses of extrapolating simple relationships determined under controlled conditions to the field vindicates the importance of both approaches. Landholders often view the idea of the productive use of saltland with skepticism. The challenge is to use the combined datasets from glasshouse and field experiments to develop information guidelines for landholders that maximize the chances of revegetation success. Water availability, waterlogging, quality of the shallow groundwater, and secondary salinity are dominant processes that impact on agriculture in southwestern Australia. Improving our understanding of their interactions and effect on productivity will help adapt agricultural management to changing environmental conditions in the future.

Shaded Relief, Kamchatka Peninsula, Russia

NASA Technical Reports Server (NTRS)

2000-01-01

This topographic image shows the western side of the volcanically active Kamchatka Peninsula, Russia. The data are from the first C-band mapping swath of the Shuttle Radar Topography Mission (SRTM). On the left side are four rivers, which flow northwest to the Sea of Okhotsk. These rivers are, from the south to north, Tigil, Amanina, Voyampolka, and Zhilovaya. The broad, flat floodplains of the rivers are shown in blue. These rivers are important spawning grounds for salmon. In the right side of the image is the Sredinnyy Khrebet, the volcanic mountain range that makes up the 3spine2 of the peninsula. The cluster of hills to the lower right is a field of small dormant volcanoes. High resolution SRTM topographic data will be used by geologists to study how volcanoes form and understand the hazards posed by future eruptions.

This shaded relief image was generated using topographic data from the Shuttle Radar Topography Mission. A computer-generated artificial light source illuminates the elevation data to produce a pattern of light and shadows. Slopes facing the light appear bright, while those facing away are shaded. On flatter surfaces, the pattern of light and shadows can reveal subtle features in the terrain. Colors show the elevation as measured by SRTM. Colors range from blue at the lowest elevations to white at the highest elevations. This image contains about 2300 meters (7500 feet) of total relief. Shaded relief maps are commonly used in applications such as geologic mapping and land use planning.

The Shuttle Radar Topography Mission (SRTM), launched on February 11,2000, uses the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. The mission is designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, an additional C-band imaging antenna and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration (NASA), the National Imagery and Mapping Agency (NIMA) and the German (DLR) and Italian (ASI) space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Earth Science Enterprise, Washington, DC.

Size: 158 km (98 miles) x 122 km (77 miles) Location: 57.5 deg. North lat., 158.8 deg. East lon. Orientation: North approximately at top Original Data Resolution: 30 meters (99 feet) Date Acquired: February 12, 2000

Topography of the overriding plate during progressive subduction: A dynamic model to explain forearc subsidence

NASA Astrophysics Data System (ADS)

Chen, Z.; Schellart, W. P.; Duarte, J. C.; Strak, V.

2017-12-01

Topography that forms at the free top surface of the lithosphere contains important information about the dynamics of the tectonic plates and the sub-lithospheric mantle. Investigating topography around subduction zones can provide quantitative and conceptual insights into the interaction between the plates, the slabs, mantle flow, and the associated stresses. To achieve this, geodynamic modelling can be an effective tool. In this study, we used techniques of stereoscopic photogrammetry and Particle Image Velocimetry to monitor simultaneously the topography of the overriding plate and the velocity field of the subduction-induced mantle flow occurring in the mantle wedge. Model results show that the overriding plate topography is characterized by an area of forearc topographic subsidence, with a magnitude scaling to 1.44-3.97 km in nature, and a transient local topographic high located between the forearc depression and the trench. These topographic features rapidly develop during the slab sinking phase and gradually decrease during the slab rollback phase. We propose that these topographic transient features predominantly result from the variation of the vertical component of the trench suction along the subduction zone interface, which is minimum near the trench and maximum near the tip of the mantle wedge and is caused by the gradual slab steepening during the initial transient slab sinking phase. The downward mantle flow in the nose of the mantle wedge plays a minor role in the formation of the forearc subsidence. Our findings provide a new mechanism for the formation of forearc topographic subsidence, which has been commonly observed at natural subduction zones.

Relative Importance of Coral Cover, Habitat Complexity and Diversity in Determining the Structure of Reef Fish Communities

PubMed Central

Komyakova, Valeriya; Munday, Philip L.; Jones, Geoffrey P.

2013-01-01

The structure of coral reef habitat has a pronounced influence on the diversity, composition and abundance of reef-associated fishes. However, the particular features of the habitat that are most critical are not always known. Coral habitats can vary in many characteristics, notably live coral cover, topographic complexity and coral diversity, but the relative effects of these habitat characteristics are often not distinguished. Here, we investigate the strength of the relationships between these habitat features and local fish diversity, abundance and community structure in the lagoon of Lizard Island, Great Barrier Reef. In a spatial comparison using sixty-six 2m2 quadrats, fish species richness, total abundance and community structure were examined in relation to a wide range of habitat variables, including topographic complexity, habitat diversity, coral diversity, coral species richness, hard coral cover, branching coral cover and the cover of corymbose corals. Fish species richness and total abundance were strongly associated with coral species richness and cover, but only weakly associated with topographic complexity. Regression tree analysis showed that coral species richness accounted for most of the variation in fish species richness (63.6%), while hard coral cover explained more variation in total fish abundance (17.4%), than any other variable. In contrast, topographic complexity accounted for little spatial variation in reef fish assemblages. In degrading coral reef environments, the potential effects of loss of coral cover and topographic complexity are often emphasized, but these findings suggest that reduced coral biodiversity may ultimately have an equal, or greater, impact on reef-associated fish communities. PMID:24349455

Relative importance of coral cover, habitat complexity and diversity in determining the structure of reef fish communities.

PubMed

Komyakova, Valeriya; Munday, Philip L; Jones, Geoffrey P

2013-01-01

The structure of coral reef habitat has a pronounced influence on the diversity, composition and abundance of reef-associated fishes. However, the particular features of the habitat that are most critical are not always known. Coral habitats can vary in many characteristics, notably live coral cover, topographic complexity and coral diversity, but the relative effects of these habitat characteristics are often not distinguished. Here, we investigate the strength of the relationships between these habitat features and local fish diversity, abundance and community structure in the lagoon of Lizard Island, Great Barrier Reef. In a spatial comparison using sixty-six 2m(2) quadrats, fish species richness, total abundance and community structure were examined in relation to a wide range of habitat variables, including topographic complexity, habitat diversity, coral diversity, coral species richness, hard coral cover, branching coral cover and the cover of corymbose corals. Fish species richness and total abundance were strongly associated with coral species richness and cover, but only weakly associated with topographic complexity. Regression tree analysis showed that coral species richness accounted for most of the variation in fish species richness (63.6%), while hard coral cover explained more variation in total fish abundance (17.4%), than any other variable. In contrast, topographic complexity accounted for little spatial variation in reef fish assemblages. In degrading coral reef environments, the potential effects of loss of coral cover and topographic complexity are often emphasized, but these findings suggest that reduced coral biodiversity may ultimately have an equal, or greater, impact on reef-associated fish communities.

Scalable topographies to support proliferation and Oct4 expression by human induced pluripotent stem cells

PubMed Central

Reimer, Andreas; Vasilevich, Aliaksei; Hulshof, Frits; Viswanathan, Priyalakshmi; van Blitterswijk, Clemens A.; de Boer, Jan; Watt, Fiona M.

2016-01-01

It is well established that topographical features modulate cell behaviour, including cell morphology, proliferation and differentiation. To define the effects of topography on human induced pluripotent stem cells (iPSC), we plated cells on a topographical library containing over 1000 different features in medium lacking animal products (xeno-free). Using high content imaging, we determined the effect of each topography on cell proliferation and expression of the pluripotency marker Oct4 24 h after seeding. Features that maintained Oct4 expression also supported proliferation and cell-cell adhesion at 24 h, and by 4 days colonies of Oct4-positive, Sox2-positive cells had formed. Computational analysis revealed that small feature size was the most important determinant of pluripotency, followed by high wave number and high feature density. Using this information we correctly predicted whether any given topography within our library would support the pluripotent state at 24 h. This approach not only facilitates the design of substrates for optimal human iPSC expansion, but also, potentially, identification of topographies with other desirable characteristics, such as promoting differentiation. PMID:26757610

Scalable topographies to support proliferation and Oct4 expression by human induced pluripotent stem cells.

PubMed

Reimer, Andreas; Vasilevich, Aliaksei; Hulshof, Frits; Viswanathan, Priyalakshmi; van Blitterswijk, Clemens A; de Boer, Jan; Watt, Fiona M

2016-01-13

It is well established that topographical features modulate cell behaviour, including cell morphology, proliferation and differentiation. To define the effects of topography on human induced pluripotent stem cells (iPSC), we plated cells on a topographical library containing over 1000 different features in medium lacking animal products (xeno-free). Using high content imaging, we determined the effect of each topography on cell proliferation and expression of the pluripotency marker Oct4 24 h after seeding. Features that maintained Oct4 expression also supported proliferation and cell-cell adhesion at 24 h, and by 4 days colonies of Oct4-positive, Sox2-positive cells had formed. Computational analysis revealed that small feature size was the most important determinant of pluripotency, followed by high wave number and high feature density. Using this information we correctly predicted whether any given topography within our library would support the pluripotent state at 24 h. This approach not only facilitates the design of substrates for optimal human iPSC expansion, but also, potentially, identification of topographies with other desirable characteristics, such as promoting differentiation.

The Importance of Capturing Topographic Features for Modeling Groundwater Flow and Transport in Mountainous Watersheds

NASA Astrophysics Data System (ADS)

Wang, C.; Gomez-Velez, J. D.; Wilson, J. L.

2017-12-01

Groundwater plays a key role in runoff generation and stream water chemistry from reach to watershed scales. The spatial distribution of ridges and streams can influence the spatial patterns of groundwater recharge and drainage, specially in mountainous terrains where these features are more prominent. However, typical modeling efforts simplify or ignore some of these features due to computational limitations without a systematic investigation of the implications for flow and transport within the watershed. In this study, we investigate the effect of capturing key topographic features on modeled groundwater flow and transport characteristics in a mountainous watershed. We build model scenarios of different topographic complexity levels (TCLs) to capture different levels of representation of streams and ridges in the model. Modeled baseflow and groundwater mean residence time (MRT) are used to quantify the differences among TCLs. Our results show that capturing the streams and ridges has a significant influence on simulated groundwater flow and transport patterns. Topographic complexity controls the proportion of baseflow generated from local, intermediate, and regional flow paths, thus influencing the amount and MRT of basefow flowing into streams of different Horton-Strahler orders. We further simulate the concentration of solute exported into streams from subsurface chemical weathering. The concentration of chemical weathering products in streams is less sensitive to model TCL due to the thermodynamic constraint on the equilibrium concentration of the chemical weathering. We also tested the influence of geology on the effect of TCL. The effect of TCL is consistent under different geological conditions; however, it is enhanced in models with low hydraulic conductivity because more of the flow is forced into shallow and local flow paths. All of these changes can affect our ability to interpret environmental tracer data and predict bio- and geo-chemical evolution of stream water in mountainous watersheds.

Kilometer-Scale Topographic Roughness of Mercury: Correlation with Geologic Features and Units

NASA Technical Reports Server (NTRS)

Kreslavsky, Mikhail A.; Head, James W.; Neumann, Gregory A.; Zuber, Maria T.; Smith, David E.

2014-01-01

We present maps of the topographic roughness of the northern circumpolar area of Mercury at kilometer scales. The maps are derived from range profiles obtained by the Mercury Laser Altimeter (MLA) instrument onboard the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) mission. As measures of roughness, we used the interquartile range of profile curvature at three baselines: 0.7 kilometers, 2.8 kilometers, and 11 kilometers. The maps provide a synoptic overview of variations of typical topographic textures. They show a dichotomy between the smooth northern plains and rougher, more heavily cratered terrains. Analysis of the scale dependence of roughness indicates that the regolith on Mercury is thicker than on the Moon by approximately a factor of three. Roughness contrasts within northern volcanic plains of Mercury indicate a younger unit inside Goethe basin and inside another unnamed stealth basin. These new data permit interplanetary comparisons of topographic roughness.

Video shot boundary detection using region-growing-based watershed method

NASA Astrophysics Data System (ADS)

Wang, Jinsong; Patel, Nilesh; Grosky, William

2004-10-01

In this paper, a novel shot boundary detection approach is presented, based on the popular region growing segmentation method - Watershed segmentation. In image processing, gray-scale pictures could be considered as topographic reliefs, in which the numerical value of each pixel of a given image represents the elevation at that point. Watershed method segments images by filling up basins with water starting at local minima, and at points where water coming from different basins meet, dams are built. In our method, each frame in the video sequences is first transformed from the feature space into the topographic space based on a density function. Low-level features are extracted from frame to frame. Each frame is then treated as a point in the feature space. The density of each point is defined as the sum of the influence functions of all neighboring data points. The height function that is originally used in Watershed segmentation is then replaced by inverting the density at the point. Thus, all the highest density values are transformed into local minima. Subsequently, Watershed segmentation is performed in the topographic space. The intuitive idea under our method is that frames within a shot are highly agglomerative in the feature space and have higher possibilities to be merged together, while those frames between shots representing the shot changes are not, hence they have less density values and are less likely to be clustered by carefully extracting the markers and choosing the stopping criterion.

Multi-source remotely sensed data fusion for improving land cover classification

NASA Astrophysics Data System (ADS)

Chen, Bin; Huang, Bo; Xu, Bing

2017-02-01

Although many advances have been made in past decades, land cover classification of fine-resolution remotely sensed (RS) data integrating multiple temporal, angular, and spectral features remains limited, and the contribution of different RS features to land cover classification accuracy remains uncertain. We proposed to improve land cover classification accuracy by integrating multi-source RS features through data fusion. We further investigated the effect of different RS features on classification performance. The results of fusing Landsat-8 Operational Land Imager (OLI) data with Moderate Resolution Imaging Spectroradiometer (MODIS), China Environment 1A series (HJ-1A), and Advanced Spaceborne Thermal Emission and Reflection (ASTER) digital elevation model (DEM) data, showed that the fused data integrating temporal, spectral, angular, and topographic features achieved better land cover classification accuracy than the original RS data. Compared with the topographic feature, the temporal and angular features extracted from the fused data played more important roles in classification performance, especially those temporal features containing abundant vegetation growth information, which markedly increased the overall classification accuracy. In addition, the multispectral and hyperspectral fusion successfully discriminated detailed forest types. Our study provides a straightforward strategy for hierarchical land cover classification by making full use of available RS data. All of these methods and findings could be useful for land cover classification at both regional and global scales.

Topographic Feature Names on Venus: Progress in 2000, Review of 1997-2000 Development, Current State, and Prospective

NASA Technical Reports Server (NTRS)

Burba, G. A.; Blue, J.; Campbell, D. B.; Dollfus, A.; Gaddis, L.; Jurgens, R. F.; Marov, M. Ya.; Pettengill, G. H.; Stofan, E. R.

2001-01-01

12 names assigned on Venus in 2000. The current list includes 1821 names of 21 feature types. 95% of names present 11 types of features. The main named types are craters - 872, and coronae - 267. These two types possess 62% of the names. Additional information is contained in the original extended abstract.

Lunar textural analysis based on WAC-derived kilometer-scale roughness and entropy maps

NASA Astrophysics Data System (ADS)

Li, Bo; Wang, XueQiang; Zhang, Jiang; Chen, Jian; Ling, Zongcheng

2016-06-01

In general, textures are thought to be some complicated repeated patterns formed by elements, or primitives which are sorted in certain rules. Lunar surfaces record the interactions between its outside environment and itself, thus, based on high-resolution DEM model or image data, there are some topographic features which have different roughness and entropy values or signatures on lunar surfaces. Textures of lunar surfaces can help us to concentrate on typical topographic and photometric variations and reveal the relationships between obvious features (craters, impact basins, sinuous rilles (SRs) and ridges) with resurfacing processes on the Moon. In this paper, the term surface roughness is an expression of the variability of a topographic or photometric surface at kilometer scale, and the term entropy can characterize the variability inherent in a geological and topographic unit and evaluate the uncertainty of predictions made by a given geological process. We use the statistical moments of gray-level histograms in different-sized neighborhoods (e.g., 3, 5, 10, 20, 40 and 80 pixels) to compute the kilometer-scale roughness and entropy values, using the mosaic image from 70°N to 70°S obtained by Lunar Reconnaissance Orbiter (LRO) Wide Angle Camera (WAC). Large roughness and entropy signatures were only found in the larger scale maps, while the smallest 3-pixel scale map had more disorderly and unsystematic textures. According to the entropy values in 10-pixel scale entropy map, we made a frequency curve and categorized lunar surfaces into three types, shadow effects, maria and highlands. A 2D scatter plot of entropy versus roughness values was produced and we found that there were two point clusters corresponding to the highlands and maria, respectively. In the last, we compared the topographic and photometric signatures derived from Lunar Orbiter Laser Altimeter (LOLA) data and WAC mosaic image. On the lunar surfaces, the ridges have obvious multilevel topographic textures which are sensitive to the topographic changes, while the ejecta deposits of fresh craters appear obvious photometric textures which are sensitive to the brightness variations.

Evaluation of ERTS-1 imagery for spectral geological mapping in diverse terranes of New York State

NASA Technical Reports Server (NTRS)

Isachsen, Y. W. (Principal Investigator); Fakundiny, R. H.; Forster, S. W.

1973-01-01

The author has identified the following significant results. Linear anomalies dominate the new geological information derived from ERTS-1 imagery, total lengths now exceeding 6000 km. Experimentation with a variety of viewing techniques suggest that conventional photogeologic analyses of band 7 results in the location of more than 97 percent of all linears found. Bedrock lithologic types are distinguishable only where they are topographically expressed or govern land use signatures. The maxima on rose diagrams for ERTS-1 anomalies correspond well with those for mapped faults and topographic lineaments. A multiscale analysis of linears showed that single topographic linears at 1:2,500,000 became dashed linears at 1:1,000,000 aligned zones of shorter parallel, en echelon, or conjugate linears at 1:500,00. Most circular features found were explained away by U-2 airphoto analysis but several remain as anomalies. Visible glacial features include individual drumlins, best seen in winter imagery, drumlinoids, eskers, ice-marginal drainage channels, glacial lake shorelines and sand plains, and end moraines.

A new stereo topographic map of Io: Implications for geology from global to local scales

NASA Astrophysics Data System (ADS)

White, Oliver L.; Schenk, Paul M.; Nimmo, Francis; Hoogenboom, Trudi

2014-06-01

We use Voyager and Galileo stereo pairs to construct the most complete stereo digital elevation model (DEM) of Io assembled to date, controlled using Galileo limb profiles. Given the difficulty of applying these two techniques to Io due to its anomalous surface albedo properties, we have experimented extensively with the relevant procedures in order to generate what we consider to be the most reliable DEMs. Our final stereo DEM covers ~75% of the globe, and we have identified a partial system of longitudinally arranged alternating basins and swells that correlates well to the distribution of mountain and volcano concentrations. We consider the correlation of swells to volcano concentrations and basins to mountain concentrations, to imply a heat flow distribution across Io that is consistent with the asthenospheric tidal heating model of Tackley et al. (2001). The stereo DEM reveals topographic signatures of regional-scale features including Loki Patera, Ra Patera, and the Tvashtar Paterae complex, in addition to previously unrecognized features including an ~1000 km diameter depression and a >2000 km long topographic arc comprising mountainous and layered plains material.

Highest Resolution Topography of 433 Eros and Implications for MUSES-C

NASA Technical Reports Server (NTRS)

Cheng, A. F.; Barnouin-Jha, O.

2003-01-01

The highest resolution observations of surface morphology and topography at asteroid 433 Eros were obtained by the Near Earth Asteroid Rendezvous (NEAR) Shoemaker spacecraft on 12 February 2001, as it landed within a ponded deposit on Eros. Coordinated observations were obtained by the imager and the laser rangefinder, at best image resolution of 1 cm/pixel and best topographic resolution of 0.4 m. The NEAR landing datasets provide unique information on rock size and height distributions and regolith processes. Rocks and soil can be distinguished photometrically, suggesting that bare rock is indeed exposed. The NEAR landing data are the only data at sufficient resolution to be relevant to hazard assessment on future landed missions to asteroids, such as the MUSES-C mission which will land on asteroid 25143 (1998 SF36) in order to obtain samples. In a typical region just outside the pond where NEAR landed, the areal coverage by resolved positive topographic features is 18%. At least one topographic feature in the vicinity of the NEAR landing site would have been hazardous for a spacecraft.

X-ray topographic studies and measurement of lattice parameter differences within synthetic diamonds grown by the reconstitution technique

NASA Astrophysics Data System (ADS)

Wierzchowski, W.; Moore, M.; Makepeace, A. P. W.; Yacoot, A.

1991-10-01

A 4 x 4 x 1.5 cu mm cuboctahedral diamond and two 0.7 mm thick slabs cut from a truncated octahedral diamond grown by the reconstitution technique were studied in different double-crystal arrangements with both conventional and synchrotron X-ray sources. The back-reflection double crystal topographs of large polished 001-plane-oriented faces intersecting different growth sectors, together with cathodoluminescence patterns, allowed identification of these sectors. A double-crystal arrangement, employing the -3 2 5 quartz reflection matching the symmetrical 004 diamond reflection in CuK(alpha 1) radiation, was used for measurement of lattice parameter differences with an accuracy of one and a half parts per million. The simultaneous investigation by means of Lang projection and section topography provided complementary information about the crystallographic defects and internal structures of growth sectors. Observation of the cuboctahedral diamond with a filter of peak transmittance at 430 nm revealed a 'Maltese cross' growth feature in the central (001) growth sector, which also affected the birefringence pattern. However, this feature only very slightly affected the double-crystal topographs.

Three responses of wetland conditions to climatic extremes in the Prairie Pothole Region

USGS Publications Warehouse

Cressey, Ryann L.; Austin, Jane; Stafford, Joshua D.

2016-01-01

Wetlands in central North Dakota were revisited after 50 years to assess changes following extreme drought and a prolonged wet period. We compared data collected during 1961–1966 to current (2013–2014) wetland conditions. We revisited 80 wetlands in 2013 and 2014 across three study areas and measured wetland area, ponded-water depth, and specific conductance. Wetlands at the three study areas responded to prolonged wet conditions in one of three ways. Wetlands at Crystal Springs became larger, and had deeper ponds of lower specific conductance in 2013–14 compared to the 1960s. Wetlands at Cottonwood were larger with deeper ponds of slightly higher specific conductance in 2013–2014. Wetlands at Mt. Moriah had only subtle changes in size, pond depth, and specific conductance between periods. Prolonged wet conditions led to merging of most wetlands (defined as the outer edge of wet-meadow vegetation) at Crystal Springs and a few wetlands at Cottonwood. Low topographic relief at Crystal Springs and Cottonwood contributed to storage of excess water in wetlands with associated responses to prolonged wet conditions. In contrast, higher topographic relief and natural outlets into two intermittent streams at Mt. Moriah resulted in wetlands being less impacted by prolonged wet conditions.

Investigating the Tectonics of Mare Crisium with Topographic Data

NASA Astrophysics Data System (ADS)

Byrne, P. K.; Klimczak, C.; Solomon, S. C.

2013-12-01

Mare Crisium is a 560-km-diameter lunar mare, 170,500 km2 in area. Like other lunar maria, Crisium has been tectonically deformed by wrinkle ridges. Early studies of the tectonics of Crisium were hampered by poor resolution or illumination conditions, however. The recent availability of high-resolution digital topographic models (DTMs) from Lunar Orbiter Laser Altimeter (LOLA) data enables a fresh assessment of lunar tectonics, including those in Mare Crisium. LOLA DTMs show that the basin is replete with wrinkle ridges, consistent with previous observations; we observe over 170. The largest such structures follow the basin outline and verge towards the interior, most notably from 30°-180° and 270°-330° azimuth (measured clockwise from north). Artificially illuminated hillshade maps derived from the DTMs, for solar azimuth angles of 0° and 180°, reveal ~east-west-orientated structures that are not readily visible in photogeological data. We identify 10 partially buried craters within Crisium, but we note a further five demarcated only by wrinkle ridges, the largest of which is ~95 km in diameter, that have no other surface manifestation. Moreover, LOLA topographic data reveal subtle ridge-like changes in relief across the mare that are virtually impossible to detect otherwise. We interpret these 13 ridges, ~30-100 km in length, as additional shortening structures that have no surficial faulted component. Surface displacement models can be fit to topographic profiles across structures to estimate displacements and geometries of the underlying faults. Models fit to one such profile (see accompanying figure) across an inward-verging ridge with 500 m of relief in the southeast of Crisium indicate that its fault dips 22°, penetrates to a depth of ~20 km (far beneath the base of the mare deposits), and accumulated ~1 km of along-slip displacement. This result, given the other large structures and inferred buried ridges in Crisium, implies that this mare experienced substantial shortening. Lunar wrinkle ridges are ascribed to some combination of mare subsidence and global contraction; if representative of lunar maria in general, our findings for Crisium suggest that these processes have shaped lunar tectonics to an extent greater than previously recognized. Structural map of Mare Crisium showing wrinkle ridges (flags give down-dip direction), buried ridges (arrows give down-slope direction), buried craters, superposed craters >5 km in diameter, and the location of the topographic profile (green line); inset shows topographic (green) and model (blue) profiles. Graticule has 10° increments in latitude and longitude.

Resolving topographic detail on Venus by modeling complex Magellan altimetry echoes

NASA Technical Reports Server (NTRS)

Lovell, Amy J.; Schloerb, F. Peter; Mcgill, George E.

1993-01-01

Magellan's altimeter is providing some of the finest resolution topography of Venus achieved to date. Nevertheless, efforts continue to improve the topographic resolution whenever possible. One effort to this end is stereoscopic imaging, which provides topography at scales similar to that of the synthetic aperture radar (SAR). However, this technique requires two SAR images of the same site to be obtained and limits the utility of this method. In this paper, we present another method to resolve topographic features at scales smaller than that of an altimeter footprint, which is more globally applicable than the stereoscopic approach. Each pulse which is transmitted by Magellan's altimeter scatters from the planet and echoes to the receiver, delayed based on the distance between the spacecraft and each surface element. As resolved in time, each element of an altimetry echo represents the sum of all points on the surface which are equidistant from the spacecraft. Thus, individual returns, as a function of time, create an echo profile which may be used to derive properties of the surface, such as the scattering law or, in this case, the topography within the footprint. The Magellan project has derived some of this information by fitting model templates to radar echo profiles. The templates are calculated based on Hagfor's Law, which assumes a smooth, gently undulating surface. In most regions these templates provide a reasonable fit to the observed echo profile; however, in some cases the surface departs from these simple assumptions and more complex profiles are observed. Specifically, we note that sub-footprint topographic relief apparently has a strong effect on the shape of the echo profile. To demonstrate the effects of sub-resolution relief on echo profiles, we have calculated the echo shapes from a wide range of simple topographic models. At this point, our topographic models have emphasized surfaces where only two dominant elevations are contained within a footprint, such as graben, ridges, crater rims, and central features in impact craters.

Multiresolution analysis of characteristic length scales with high-resolution topographic data

NASA Astrophysics Data System (ADS)

Sangireddy, Harish; Stark, Colin P.; Passalacqua, Paola

2017-07-01

Characteristic length scales (CLS) define landscape structure and delimit geomorphic processes. Here we use multiresolution analysis (MRA) to estimate such scales from high-resolution topographic data. MRA employs progressive terrain defocusing, via convolution of the terrain data with Gaussian kernels of increasing standard deviation, and calculation at each smoothing resolution of (i) the probability distributions of curvature and topographic index (defined as the ratio of slope to area in log scale) and (ii) characteristic spatial patterns of divergent and convergent topography identified by analyzing the curvature of the terrain. The MRA is first explored using synthetic 1-D and 2-D signals whose CLS are known. It is then validated against a set of MARSSIM (a landscape evolution model) steady state landscapes whose CLS were tuned by varying hillslope diffusivity and simulated noise amplitude. The known CLS match the scales at which the distributions of topographic index and curvature show scaling breaks, indicating that the MRA can identify CLS in landscapes based on the scaling behavior of topographic attributes. Finally, the MRA is deployed to measure the CLS of five natural landscapes using meter resolution digital terrain model data. CLS are inferred from the scaling breaks of the topographic index and curvature distributions and equated with (i) small-scale roughness features and (ii) the hillslope length scale.

Localized damage caused by topographic amplification during the 2010 M7.0 Haiti earthquake

USGS Publications Warehouse

Hough, S.E.; Altidor, J.R.; Anglade, D.; Given, D.; Janvier, M.G.; Maharrey, J.Z.; Meremonte, M.; Mildor, B.S.-L.; Prepetit, C.; Yong, A.

2010-01-01

Local geological conditions, including both near-surface sedimentary layers and topographic features, are known to significantly influence ground motions caused by earthquakes. Microzonation maps use local geological conditions to characterize seismic hazard, but commonly incorporate the effect of only sedimentary layers. Microzonation does not take into account local topography, because significant topographic amplification is assumed to be rare. Here we show that, although the extent of structural damage in the 2010 Haiti earthquake was primarily due to poor construction, topographic amplification contributed significantly to damage in the district of Petionville, south of central Port-au-Prince. A large number of substantial, relatively well-built structures situated along a foothill ridge in this district sustained serious damage or collapse. Using recordings of aftershocks, we calculate the ground motion response at two seismic stations along the topographic ridge and at two stations in the adjacent valley. Ground motions on the ridge are amplified relative to both sites in the valley and a hard-rock reference site, and thus cannot be explained by sediment-induced amplification. Instead, the amplitude and predominant frequencies of ground motion indicate the amplification of seismic waves by a narrow, steep ridge. We suggest that microzonation maps can potentially be significantly improved by incorporation of topographic effects. ?? 2010 Macmillan Publishers Limited. All rights reserved.

40 CFR 61.32 - Emission standard.

Code of Federal Regulations, 2010 CFR

2010-07-01

... frequency of calibration. (b) Method of sample analysis. (c) Averaging technique for determining 30-day...) Plant and sampling area plots showing emission points and sampling sites. Topographic features...

IMAGING SPECTROSCOPY FOR DETERMINING RANGELAND STRESSORS TO WESTERN WATERSHEDS

EPA Science Inventory

The Environmental Protection Agency is developing rangeland ecological indicators in twelve western states using advanced remote sensing techniques. Fine spectral resolution (hyperspectral) sensors, or imaging spectrometers, can detect the subtle spectral features that make veget...

IMAGING SPECTROSCOPY FOR DETERMINING RANGELAND STRESSORS TO WESTERN WATERSHEDS

EPA Science Inventory

The Environmental Protection Agency is developing rangeland ecological indicators in eleven western states using advanced remote sensing systems. Fine spectral resolution (hyperspemal) sensors, or imaging spectrometers, can detect the subtle spectral features that makes vegetatio...

Automated Detection of Diabetic Retinopathy using Deep Learning.

PubMed

Lam, Carson; Yi, Darvin; Guo, Margaret; Lindsey, Tony

2018-01-01

Diabetic retinopathy is a leading cause of blindness among working-age adults. Early detection of this condition is critical for good prognosis. In this paper, we demonstrate the use of convolutional neural networks (CNNs) on color fundus images for the recognition task of diabetic retinopathy staging. Our network models achieved test metric performance comparable to baseline literature results, with validation sensitivity of 95%. We additionally explored multinomial classification models, and demonstrate that errors primarily occur in the misclassification of mild disease as normal due to the CNNs inability to detect subtle disease features. We discovered that preprocessing with contrast limited adaptive histogram equalization and ensuring dataset fidelity by expert verification of class labels improves recognition of subtle features. Transfer learning on pretrained GoogLeNet and AlexNet models from ImageNet improved peak test set accuracies to 74.5%, 68.8%, and 57.2% on 2-ary, 3-ary, and 4-ary classification models, respectively.

Functional Topography of Human Auditory Cortex

PubMed Central

Rauschecker, Josef P.

2016-01-01

Functional and anatomical studies have clearly demonstrated that auditory cortex is populated by multiple subfields. However, functional characterization of those fields has been largely the domain of animal electrophysiology, limiting the extent to which human and animal research can inform each other. In this study, we used high-resolution functional magnetic resonance imaging to characterize human auditory cortical subfields using a variety of low-level acoustic features in the spectral and temporal domains. Specifically, we show that topographic gradients of frequency preference, or tonotopy, extend along two axes in human auditory cortex, thus reconciling historical accounts of a tonotopic axis oriented medial to lateral along Heschl's gyrus and more recent findings emphasizing tonotopic organization along the anterior–posterior axis. Contradictory findings regarding topographic organization according to temporal modulation rate in acoustic stimuli, or “periodotopy,” are also addressed. Although isolated subregions show a preference for high rates of amplitude-modulated white noise (AMWN) in our data, large-scale “periodotopic” organization was not found. Organization by AM rate was correlated with dominant pitch percepts in AMWN in many regions. In short, our data expose early auditory cortex chiefly as a frequency analyzer, and spectral frequency, as imposed by the sensory receptor surface in the cochlea, seems to be the dominant feature governing large-scale topographic organization across human auditory cortex. SIGNIFICANCE STATEMENT In this study, we examine the nature of topographic organization in human auditory cortex with fMRI. Topographic organization by spectral frequency (tonotopy) extended in two directions: medial to lateral, consistent with early neuroimaging studies, and anterior to posterior, consistent with more recent reports. Large-scale organization by rates of temporal modulation (periodotopy) was correlated with confounding spectral content of amplitude-modulated white-noise stimuli. Together, our results suggest that the organization of human auditory cortex is driven primarily by its response to spectral acoustic features, and large-scale periodotopy spanning across multiple regions is not supported. This fundamental information regarding the functional organization of early auditory cortex will inform our growing understanding of speech perception and the processing of other complex sounds. PMID:26818527

Modification of Surface Energy via Direct Laser Ablative Surface Patterning

NASA Technical Reports Server (NTRS)

Wohl, Christopher J., Jr. (Inventor); Belcher, Marcus A. (Inventor); Connell, John W. (Inventor); Hopkins, John W. (Inventor)

2015-01-01

Surface energy of a substrate is changed without the need for any template, mask, or additional coating medium applied to the substrate. At least one beam of energy directly ablates a substrate surface to form a predefined topographical pattern at the surface. Each beam of energy has a width of approximately 25 micrometers and an energy of approximately 1-500 microJoules. Features in the topographical pattern have a width of approximately 1-500 micrometers and a height of approximately 1.4-100 micrometers.

Topographic maps: Tools for planning

USGS Publications Warehouse

Kaufman, George A.

1980-01-01

Topographic maps are a detailed record of a land area, giving geographic positions and elevations for both natural and man-made features. They show the shape of the land the mountains, valleys, and plains by means of brown contour lines (lines of equal elevation above sea level). In steep mountainous areas, contours are closely spaced; in flatter areas, they are far apart. The elevation of any point on the map can be estimated by referring to the elevations of the contour lines above and below it.

Development of antifouling surfaces to reduce bacterial attachment

NASA Astrophysics Data System (ADS)

Graham, Mary Viola

Bacteria are exceptionally good at adhering to surfaces and forming complex structures known as biofilms. This process, known as biofouling, can cause problems for infrastructure (eg, clogging and damaging pipes), for the food industry (eg, contamination of processing surfaces and equipment, and for the medical industry (eg, contamination of indwelling medical devices). Accordingly, multiple strategies have been explored to combat biofouling, including chemical modification of surfaces, development of antibiotic coatings, and more recently, the use of engineered surface topography. When designed properly, engineered surface topographies can significantly reduce bacterial surface attachment, ultimately limiting surface colonization. In this work, we hypothesized that the morphology, size, spacing, and surface pre-treatment of topographical features should directly correlate with the size and shape of target organisms, in order to reduce biofouling. Topographical features with size and spacing from 0.25 to 2 mum were fabricated in silicone elastomer and tested against rod shaped bacteria with an average size of 0.5 x 2 mum and spherical bacteria (cocci) ranging from 0.5 - 1 μm in diameter. Antifouling properties of the different topographical features were tested in both static and flow-based assays, and under oxygen plasma-treated (hydrophilic) and untreated (hydrophobic) surface conditions. We found that surface pre-treatment universally affects the ability bacteria to attach to surfaces, while surface topography limits attachment in a manner dependent on the bacterial size/shape and the size/spacing of the topography.

Fault zone structure and inferences on past activities of the active Shanchiao Fault in the Taipei metropolis, northern Taiwan

NASA Astrophysics Data System (ADS)

Chen, C.; Lee, J.; Chan, Y.; Lu, C.

2010-12-01

The Taipei Metropolis, home to around 10 million people, is subject to seismic hazard originated from not only distant faults or sources scattered throughout the Taiwan region, but also active fault lain directly underneath. Northern Taiwan including the Taipei region is currently affected by post-orogenic (Penglai arc-continent collision) processes related to backarc extension of the Ryukyu subduction system. The Shanchiao Fault, an active normal fault outcropping along the western boundary of the Taipei Basin and dipping to the east, is investigated here for its subsurface structure and activities. Boreholes records in the central portion of the fault were analyzed to document the stacking of post- Last Glacial Maximum growth sediments, and a tulip flower structure is illuminated with averaged vertical slip rate of about 3 mm/yr. Similar fault zone architecture and post-LGM tectonic subsidence rate is also found in the northern portion of the fault. A correlation between geomorphology and structural geology in the Shanchiao Fault zone demonstrates an array of subtle geomorphic scarps corresponds to the branch fault while the surface trace of the main fault seems to be completely erased by erosion and sedimentation. Such constraints and knowledge are crucial in earthquake hazard evaluation and mitigation in the Taipei Metropolis, and in understanding the kinematics of transtensional tectonics in northern Taiwan. Schematic 3D diagram of the fault zone in the central portion of the Shanchiao Fault, displaying regional subsurface geology and its relation to topographic features.

Cryptoblemes: A New Discovery with Major Economic Implications and Profound Changes to the Geologic Paradigm

NASA Technical Reports Server (NTRS)

Windolph, J., Jr.; Sutton, J.

1997-01-01

Cryptoblemes are subtle impact shock signatures imprinted by cosmic debris on the crustal surfaces of lunar planetary bodes. These signatures constitute a complex cumulative overprinting of topographic, structural geophysical, and tectonic patterns that have a conspicuous radial centric multiringed symmetry. The geometry and distribution of cryptoblemes on Earth is comparable to the size and density of impact features on lunar planetary surfaces. Analysis of satellite imagery, sea-floor sonar, side-looking radar and aerial photographs of specific sites reveals new criteria for the identification and confirmation of impact-shock signatures. These criteria include joint and foliation patterns with asbestiform minerals, ribbon-quartz, spheroidal weathering, domal exfoliation, pencil shale, and shock spheres, which may originate from hydrocavitation of water-saturated sedimentary rocks. Cryptoblemes may also be associated with breccia pipes, sinkholes, buttes, mesas, and bogs, high-Rn anomalies, nodular concentrations, and earthquake epicenters. Major implications of cryptobleme identification include exploratory targeting of hydrocarbon and mineral deposits and the explanation of their origins. Analysis of known mineral deposits, structural traps and sedimentary basins show a direct correlation with cryptobleme patterns. Significant geologic paradigm shifts related to cryptoblemes include mountain building processes, structural orogenies, induced volcanism, earthquake origins, hydrocarbon diagenesis, formation mineral deposits, continental rifting, and plate movements, magnetic overprinting and local regional, and global geologic extinction and speciation patterns. Two figures provide a comparison between a multiring impact overprint in water and multiring cryptobleme in the U.S. basin range. (Additional information is contained in the original document).

Fractal Complexity-Based Feature Extraction Algorithm of Communication Signals

NASA Astrophysics Data System (ADS)

Wang, Hui; Li, Jingchao; Guo, Lili; Dou, Zheng; Lin, Yun; Zhou, Ruolin

How to analyze and identify the characteristics of radiation sources and estimate the threat level by means of detecting, intercepting and locating has been the central issue of electronic support in the electronic warfare, and communication signal recognition is one of the key points to solve this issue. Aiming at accurately extracting the individual characteristics of the radiation source for the increasingly complex communication electromagnetic environment, a novel feature extraction algorithm for individual characteristics of the communication radiation source based on the fractal complexity of the signal is proposed. According to the complexity of the received signal and the situation of environmental noise, use the fractal dimension characteristics of different complexity to depict the subtle characteristics of the signal to establish the characteristic database, and then identify different broadcasting station by gray relation theory system. The simulation results demonstrate that the algorithm can achieve recognition rate of 94% even in the environment with SNR of -10dB, and this provides an important theoretical basis for the accurate identification of the subtle features of the signal at low SNR in the field of information confrontation.

Application of PALSAR-2 remote sensing data for structural geology and topographic mapping in Kelantan river basin, Malaysia

NASA Astrophysics Data System (ADS)

Beiranvand Pour, Amin; Hashim, Mazlan

2016-06-01

Natural hazards of geological origin are one of major problem during heavy monsoons rainfall in Kelantan state, peninsular Malaysia. Several landslides occur in this region are obviously connected to geological and topographical features, every year. Satellite synthetic aperture radar (SAR) data are particularly applicable for detection of geological structural and topographical features in tropical conditions. In this study, Phased Array type L-band Synthetic Aperture Radar (PALSAR-2), remote sensing data were used to identify high potential risk and susceptible zones for landslide in the Kelantan river basin. Adaptive Local Sigma filter was selected and applied to accomplish speckle reduction and preserving both edges and features in PALSAR-2 fine mode observation images. Different polarization images were integrated to enhance geological structures. Additionally, directional filters were applied to the PALSAR-2 Local Sigma resultant image for edge enhancement and detailed identification of linear features. Several faults, drainage patterns and lithological contact layers were identified at regional scale. In order to assess the results, fieldwork and GPS survey were conducted in the landslide affected zones in the Kelantan river basin. Results demonstrate the most of the landslides were associated with N-S, NNW-SSE and NE-SW trending faults, angulate drainage pattern and metamorphic and Quaternary units. Consequently, geologic structural map were produced for Kelantan river basin using recent PALSAR-2 data, which could be broadly applicable for landslide hazard assessment and delineation of high potential risk and susceptible areas. Landslide mitigation programmes could be conducted in the landslide recurrence regions for reducing catastrophes leading to economic losses and death.

Estimating Douglas-fir site quality from aerial photographs.

Treesearch

Grover A. Choate

1961-01-01

This study investigated the feasibility of developing a technique for estimating site index of Douglas-fir in the Pacific Northwest, using aerial photos and topographic maps. Physiographic features were used as indicators of site index. Analysis showed that although most of the features were highly significant as criteria for predicting site index, they explained less...

Mines, prospects, and occurrences of nonmetallic mineral commodities in the Greenville 1 degree by 2 degrees Quadrangle, South Carolina, Georgia, and North Carolina

USGS Publications Warehouse

D'Agostino, John P.; O'Connor, Bruce J.; Zupan, Alan J.W.; Maybin, Arthur H.

1994-01-01

Mines, prospects, and occurrences of nonmetal mineral commodities in the Greenville 1° x 2° quadrangle are tabulated in this report. There are 488 symbols representing 579 mines, prospects, and occurrences located in the quadrangle. There are 379 symbols used for 466 features in Georgia, 106 symbols for 110 features in South Carolina, and 3 symbols for 3 features in North Carolina. The table lists, in consecutive orders for each county (fig. 1), the map number of each feature, which correlates and locates the item on the accompanying Greenville 1° x 2° quadrangle map. Also listed are the known name of the feature; the 7.5 topographic map on which the commodity site is located; the Transverse Mercator (UTM) northing and easting grid coordinates from the appropriate 7.5’ topographic map; the commodity; remarks; and references. Some locations are known, but many sites are not verified and their locations are only approximate. Reference are listed in References Cited and referred to by number to save space. The generalized tectonic framework for the quadrangle is shown in figure 2.

Three-dimensional perspective software for representation of digital imagery data. [Olympic National Park, Washington

NASA Technical Reports Server (NTRS)

Junkin, B. G.

1980-01-01

A generalized three dimensional perspective software capability was developed within the framework of a low cost computer oriented geographically based information system using the Earth Resources Laboratory Applications Software (ELAS) operating subsystem. This perspective software capability, developed primarily to support data display requirements at the NASA/NSTL Earth Resources Laboratory, provides a means of displaying three dimensional feature space object data in two dimensional picture plane coordinates and makes it possible to overlay different types of information on perspective drawings to better understand the relationship of physical features. An example topographic data base is constructed and is used as the basic input to the plotting module. Examples are shown which illustrate oblique viewing angles that convey spatial concepts and relationships represented by the topographic data planes.

Why Are Some GCSE Examination Questions Harder to Mark Accurately than Others? Using Kelly's Repertory Grid Technique to Identify Relevant Question Features

ERIC Educational Resources Information Center

Suto, W. M. Irenka; Nadas, Rita

2009-01-01

It has long been established that marking accuracy in public examinations varies considerably among subjects and markers. This is unsurprising, given the diverse cognitive strategies that the marking process can entail, but what makes some questions harder to mark accurately than others? Are there distinct but subtle features of questions and…

Kilometer-scale topographic roughness of Mercury: Correlation with geologic features and units

NASA Astrophysics Data System (ADS)

Kreslavsky, Mikhail A.; Head, James W.; Neumann, Gregory A.; Zuber, Maria T.; Smith, David E.

2014-12-01

We present maps of the topographic roughness of the northern circumpolar area of 30 Mercury at kilometer scales. The maps are derived from range profiles obtained by the 31 Mercury Laser Altimeter (MLA) instrument onboard the MErcury Surface, Space 32 ENvironment, Geochemistry, and Ranging (MESSENGER) mission. As measures of 33 roughness, we used the interquartile range of profile curvature at three baselines: 0.7 km, 34 2.8 km, and 11 km. The maps provide a synoptic overview of variations of typical 35 topographic textures. They show a dichotomy between the smooth northern plains and 36 rougher, more heavily cratered terrains. Analysis of the scale dependence of roughness 37 indicates that the regolith on Mercury is thicker than on the Moon by approximately a 38 factor of three. Roughness contrasts within northern volcanic plains of Mercury indicate a 39 younger unit inside Goethe basin and inside another unnamed stealth basin. These new 40 data permit interplanetary comparisons of topographic roughness.

Photogrammetric portrayal of Mars topography.

USGS Publications Warehouse

Wu, S.S.C.

1979-01-01

Special photogrammetric techniques have been developed to portray Mars topography, using Mariner and Viking imaging and nonimaging topographic information and earth-based radar data. Topography is represented by the compilation of maps at three scales: global, intermediate, and very large scale. The global map is a synthesis of topographic information obtained from Mariner 9 and earth-based radar, compiled at a scale of 1:25,000,000 with a contour interval of 1 km; it gives a broad quantitative view of the planet. At intermediate scales, Viking Orbiter photographs of various resolutions are used to compile detailed contour maps of a broad spectrum of prominent geologic features; a contour interval as small as 20 m has been obtained from very high resolution orbital photography. Imagery from the Viking lander facsimile cameras permits construction of detailed, very large scale (1:10) topographic maps of the terrain surrounding the two landers; these maps have a contour interval of 1 cm. This paper presents several new detailed topographic maps of Mars.-Author

Photogrammetric portrayal of Mars topography

NASA Technical Reports Server (NTRS)

Wu, S. S. C.

1979-01-01

Special photogrammetric techniques have been developed to portray Mars topography, using Mariner and Viking imaging and nonimaging topographic information and earth-based radar data. Topography is represented by the compilation of maps at three scales: global, intermediate, and very large scale. The global map is a synthesis of topographic information obtained from Mariner 9 and earth-based radar, compiled at a scale of 1:25,000,000 with a contour interval of 1 km; it gives a broad quantitative view of the planet. At intermediate scales, Viking Orbiter photographs of various resolutions are used to compile detailed contour maps of a broad spectrum of prominent geologic features; a contour interval as small as 20 m has been obtained from very high resolution orbital photography. Imagery from the Viking lander facsimile cameras permits construction of detailed, very large scale (1:10) topographic maps of the terrain surrounding the two landers; these maps have a contour interval of 1 cm. This paper presents several new detailed topographic maps of Mars.

Derivation of surface properties from Magellan altimetry data

NASA Astrophysics Data System (ADS)

Lovell, Amy J.; Schloerb, F. Peter; McGill, George E.

1992-12-01

The fit of the Hagfors model to the Magellan altimetry data provides a means to characterize the surface properties of Venus. However, the derived surface properties are only meaningful if the model provides a good representation of the data. The Hagfors model provides a good representation of the data. The Hagfors model is generally a realistic fit to surface scattering properties of a nadir-directed antenna such as the Magellan altimeter; however, some regions of the surface of Venus are poorly described by the existing model, according to the goodness of fit parameter provided on the ARCDR CD-ROMs. Poorly characterized regions need to be identified and fit to new models in order to derive more accurate surface properties for use in inferring the geological processes that affect the surface in those regions. We have compared the goodness of fit of the Hagfors model to the distribution of features across the planet, and preliminary results show a correlation between steep topographic slopes and poor fits to the standard model, as has been noticed by others. In this paper, we investigate possible relations between many classes of features and the ability of the Hagfors model to fit the observed echo profiles. In the regions that are not well characterized by existing models, we calculate new models that compensate for topographic relief in order to derive improved estimates of surface properties. Areas investigated to date span from longitude 315 through 45, at all latitudes covered by Magellan. A survey of those areas yields preliminary results that suggest that topographically high regions are well suited to the current implementation of the Hagfors model. Striking examples of such large-scale good fits are Alpha Regio, the northern edges of Lada Terra, and the southern edge of Ishtar Terra. Other features that are typically well fit are the rims of coronae such as Heng-O and the peaks of volcanos such as Gula Mons. Surprisingly, topographically low regions, such as the ubiquitous plains areas, are modeled poorly in comparison. However, this generalization has has exceptions: Lakshmi Planum is an elevated region that is not well fit compared to the rest of neighboring Ishtar, while the southern parts of topographically low Guinevere Planitia are characterized quite well by the Hagfors model. Features that are candidates for improved models are impact craters, coronae, ridges of significant scale, complex ridged terrains, moderate-sized mountains, and sharp terrain boundaries. These features are chosen because the goodness of fit is likely to be most affected either by departures from normal incidence angles or by sharp changes in terrain type within a single footprint. Most large features that are elevated with respect to their surroundings will suffer from steep slope effects, and smaller coronae and impact craters will probably suffer due to rapid changes in their appearance within a single footprint (10-20 km).

Derivation of surface properties from Magellan altimetry data

NASA Technical Reports Server (NTRS)

Lovell, Amy J.; Schloerb, F. Peter; Mcgill, George E.

1992-01-01

The fit of the Hagfors model to the Magellan altimetry data provides a means to characterize the surface properties of Venus. However, the derived surface properties are only meaningful if the model provides a good representation of the data. The Hagfors model provides a good representation of the data. The Hagfors model is generally a realistic fit to surface scattering properties of a nadir-directed antenna such as the Magellan altimeter; however, some regions of the surface of Venus are poorly described by the existing model, according to the goodness of fit parameter provided on the ARCDR CD-ROMs. Poorly characterized regions need to be identified and fit to new models in order to derive more accurate surface properties for use in inferring the geological processes that affect the surface in those regions. We have compared the goodness of fit of the Hagfors model to the distribution of features across the planet, and preliminary results show a correlation between steep topographic slopes and poor fits to the standard model, as has been noticed by others. In this paper, we investigate possible relations between many classes of features and the ability of the Hagfors model to fit the observed echo profiles. In the regions that are not well characterized by existing models, we calculate new models that compensate for topographic relief in order to derive improved estimates of surface properties. Areas investigated to date span from longitude 315 through 45, at all latitudes covered by Magellan. A survey of those areas yields preliminary results that suggest that topographically high regions are well suited to the current implementation of the Hagfors model. Striking examples of such large-scale good fits are Alpha Regio, the northern edges of Lada Terra, and the southern edge of Ishtar Terra. Other features that are typically well fit are the rims of coronae such as Heng-O and the peaks of volcanos such as Gula Mons. Surprisingly, topographically low regions, such as the ubiquitous plains areas, are modeled poorly in comparison. However, this generalization has has exceptions: Lakshmi Planum is an elevated region that is not well fit compared to the rest of neighboring Ishtar, while the southern parts of topographically low Guinevere Planitia are characterized quite well by the Hagfors model. Features that are candidates for improved models are impact craters, coronae, ridges of significant scale, complex ridged terrains, moderate-sized mountains, and sharp terrain boundaries. These features are chosen because the goodness of fit is likely to be most affected either by departures from normal incidence angles or by sharp changes in terrain type within a single footprint. Most large features that are elevated with respect to their surroundings will suffer from steep slope effects, and smaller coronae and impact craters will probably suffer due to rapid changes in their appearance within a single footprint (10-20 km).

Detecting and Quantifying Topography in Neural Maps

PubMed Central

Yarrow, Stuart; Razak, Khaleel A.; Seitz, Aaron R.; Seriès, Peggy

2014-01-01

Topographic maps are an often-encountered feature in the brains of many species, yet there are no standard, objective procedures for quantifying topography. Topographic maps are typically identified and described subjectively, but in cases where the scale of the map is close to the resolution limit of the measurement technique, identifying the presence of a topographic map can be a challenging subjective task. In such cases, an objective topography detection test would be advantageous. To address these issues, we assessed seven measures (Pearson distance correlation, Spearman distance correlation, Zrehen's measure, topographic product, topological correlation, path length and wiring length) by quantifying topography in three classes of cortical map model: linear, orientation-like, and clusters. We found that all but one of these measures were effective at detecting statistically significant topography even in weakly-ordered maps, based on simulated noisy measurements of neuronal selectivity and sparse sampling of the maps. We demonstrate the practical applicability of these measures by using them to examine the arrangement of spatial cue selectivity in pallid bat A1. This analysis shows that significantly topographic arrangements of interaural intensity difference and azimuth selectivity exist at the scale of individual binaural clusters. PMID:24505279

Topographic Comparisons of Uplift Features on Venus and Earth

NASA Astrophysics Data System (ADS)

Stoddard, P. R.; Jurdy, D. M.

2009-12-01

Earth and Venus, nearly twins, have very different resurfacing histories. Like the Earth, Venus has a global rift system, often cited as evidence of tectonic activity, despite the apparent lack of Earth-style plate tectonics. Both systems are marked by large ridges, usually with central grabens. On Earth, the topography of the rifts can be modeled well by a cooling half-space and the spreading of two divergent plates. The origin of the topographic signature on Venus, however, remains enigmatic. Venus and Earth also both have regions of apparent upwelling: hotspots on Earth, and regiones on Venus. Both are marked by broad topographic and geoid highs as well as evidence of volcanic activity. We use topographic profiles to compare well-understood terrestrial analogs to venusian features. Specifically, we cross-correlate average profiles for terrestrial rifts (slow, fast, incipient and extinct) and hotspots (oceanic and continental) with those for venusian chasmata and regiones. We perform a principal component analysis to objectively assess degrees of similarity and differences to draw inferences as to the processes responsible for shaping Venus' surface. We analyze profiles of the Labrador Ridge, East African Rift, slow-spreading Mid-Atlantic Ridge and the fast-spreading East Pacific Rise for comparison with profiles for several venusian chasmata in different settings. For upwelling regions, we look at the Hawaii, Iceland, Reunion, and Yellowstone hotspots and Atla, Beta, and W. Eistla regiones on Venus. For ridge features, we take profiles perpendicular to the ridge trend every half-degree or so. For uplift features, we take 36 radial profiles through the center of the feature at 10 degree intervals. We use profiles from 800 to 1200 km long. For each feature, we average all profiles, then cross-correlate the individual profiles with the resulting average. Next, we cross-correlate the average profiles of each feature with those of the other features. Thus we obtain a correlation matrix. Not surprisingly, the most closely-related features (the MAR and EPR spreading rifts on Earth; Atla, Beta, and W. Eistla regiones on Venus) have the highest cross-correlations. Next highest are the correlations between the venusian and terrestrial rifts, and the correlation between the Yellowstone hotspot and Atla and Beta regiones. Yellowstone correlated only moderately well with the oceanic hotspots and Veuns' W. Eistla. Correlations with Iceland are probably somewhat poorer than might be expected, due to Iceland's proximity to Greenland. Interestingly, using shorter profile lengths, we have found that Atla and Beta most closely correlate with Earth's spreading rifts, in agreement with these regiones being recognized as the most rift-dominated on Venus. The topography of the more local constructs of the regiones is dominated by rifting, but the longer wavelength profiles reflect the larger-area upwelling processes. These correlations of topography can provide useful tools for a quantitative comparison of planetary features, and to infer tectonic and volcanic processes on Venus.

HCMM: Soil moisture in relation to geologic structure and lithology, northern California

NASA Technical Reports Server (NTRS)

Rich, E. I. (Principal Investigator)

1979-01-01

The author has identified the following significant results. First-look qualitative geologic evaluation of day- and night-IR images discloses several en echelon linear features extending throughout the central part of the northern coast range in California, across the Mendocino triple junction and into southern Oregon. Preliminary examination of these features with respect to topographic expression, vegetation, sun angle and azimuth, and atmospheric conditions suggests that they may be related to the intracontinental plate boundary (Lake Mountain Fault zone of Herd) of the Humbolt Plate. The linear features, which cut across several climatic zones and differently vegetated regions are not confined to topographic valleys, but cross the ridges and valleys at varying angles. Lithology within the Great Valley Sequence can be detected on a few of the images; however, preliminary evaluation suggests that the thermal banding observed may be a function of sun azimuth or late-day sun angle. Soil moisture, related to lithologic composition cannot be ruled out at this time.

Evaluation of the effects of the seasonal variation of solar elevation angle and azimuth on the processes of digital filtering and thematic classification of relief units

NASA Technical Reports Server (NTRS)

Parada, N. D. J. (Principal Investigator); Novo, E. M. L. M.

1983-01-01

The effects of the seasonal variation of illumination over digital processing of LANDSAT images are evaluated. Two sets of LANDSAT data referring to the orbit 150 and row 28 were selected with illumination parameters varying from 43 deg to 64 deg for azimuth and from 30 deg to 36 deg for solar elevation respectively. IMAGE-100 system permitted the digital processing of LANDSAT data. Original images were transformed by means of digital filtering so as to enhance their spatial features. The resulting images were used to obtain an unsupervised classification of relief units. Topographic variables (declivity, altitude, relief range and slope length) were used to identify the true relief units existing on the ground. The LANDSAT over pass data show that digital processing is highly affected by illumination geometry, and there is no correspondence between relief units as defined by spectral features and those resulting from topographic features.

Geology of the Venus equatorial region from Pioneer Venus radar imaging

NASA Technical Reports Server (NTRS)

Senske, D. A.; Head, James W.

1989-01-01

The surface characteristics and morphology of the equatorial region of Venus were first described by Masursky et al. who showed this part of the planet to be characterized by two topographic provinces, rolling plains and highlands, and more recently by Schaber who described and interpreted tectonic zones in the highlands. Using Pioneer Venus (PV) radar image data (15 deg S to 45 deg N), Senske and Head examined the distribution, characteristics, and deposits of individual volcanic features in the equatorial region, and in addition classified major equatorial physiographic and tectonic units on the basis of morphology, topographic signature, and radar properties derived from the PV data. Included in this classification are: plains (undivided), inter-highland tectonic zones, tectonically segmented linear highlands, upland rises, tectonic junctions, dark halo plains, and upland plateaus. In addition to the physiographic units, features interpreted as coronae and volcanic mountains have also been mapped. The latter four of the physiographic units along with features interpreted to be coronae.

43 CFR 3482.1 - Exploration and resource recovery and protection plans.

Code of Federal Regulations, 2012 CFR

2012-10-01

...; earth- or debris-disposal areas; existing bodies of surface water; and topographic and drainage features... to, mining sequence, production rate, estimated recovery factors, stripping ratios, highwall limits...

To evaluate ERTS-1 data for usefulness as a geological sensor in the diverse geological terraines of New York State

NASA Technical Reports Server (NTRS)

Isachsen, Y. W. (Principal Investigator)

1973-01-01

The author has identified the following significant results. Linear anomalies dominate the new geological information derived from ERTS-1 imagery, total lengths now exceeding 6000 kms. Experimentation with a variety of viewing techniques suggests that conventional photogeologic analyses of band 7 results in the location of more than 97 percent of all linears found. Bedrock lithologic types are distinguishable only where they are topographically expressed or govern land use signatures. The maxima on rose diagrams for ERTS-1 anomalies correspond well with those for mapped faults and topographic lineaments, despite a difference in relative magnitudes of maxima thought due to solar illumination direction. A multiscale analysis of linears showed that single topographic linears at 1:2,500,000 became dashed jugate linears at 1:500,000, and shorter linears lacking any conspicuous zonal alignment at 1:250,000. Most circular features found were explained away by U-2 airphoto analysis but several remain as anomalies. Visible glacial features include individual drumlins, best seen in winter imagery, drumlinoids, eskers, ice-marginal drainage channels, glacial lake shorelines and sand plains, and end moraines.

Tip-Enhanced Raman Imaging and Nano Spectroscopy of Etched Silicon Nanowires

PubMed Central

Kazemi-Zanjani, Nastaran; Kergrene, Erwan; Liu, Lijia; Sham, Tsun-Kong; Lagugné-Labarthet, François

2013-01-01

Tip-enhanced Raman spectroscopy (TERS) is used to investigate the influence of strains in isolated and overlapping silicon nanowires prepared by chemical etching of a (100) silicon wafer. An atomic force microscopy tip made of nanocrystalline diamond coated with a thin layer of silver is used in conjunction with an excitation wavelength of 532 nm in order to probe the first order optical phonon mode of the [100] silicon nanowires. The frequency shift and the broadening of the silicon first order phonon are analyzed and compared to the topographical measurements for distinct configuration of nanowires that are disposed in straight, bent or overlapping configuration over a microscope coverslip. The TERS spatial resolution is close to the topography provided by the nanocrystalline diamond tip and subtle spectral changes are observed for different nanowire configurations. PMID:24072021

The NEAR laser ranging investigation

NASA Astrophysics Data System (ADS)

Zuber, M. T.; Smith, D. E.; Cheng, A. F.; Cole, T. D.

1997-10-01

The objective of the NEAR-Earth Asteriod Rendezvous (NEAR) laser ranging investigation is to obtain high integrity profiles and grids of topography for use in geophysical, geodetic and geological studies of asteroid 433 Eros. The NEAR laser rangefinder (NLR) will determine the slant range of the NEAR spacecraft to the asteroid surface by measuring precisely the round trip time of flight of individual laser pulses. Ranges will be converted to planetary radii measured with respect to the asteroid center of mass by subtracting the spacecraft orbit determined from X band Doppler tracking. The principal components of the NLR include a 1064 nm Cr:Nd:YAG laser, a gold-coated aluminum Dall-Kirkham Cassegrain telescope, an enhanced silicon avalanche photodiode hybrid detector, a 480-MHz crystal oscillator, and a digital processing unit. The instrument has a continuous in-flight calibration capability using a fiber-optic delay assembly. The single shot vertical resolution of the NLR is <6m, and the absolute accuracy of the global grid will be ~10m with respect to the asteroid center of mass. For the current mission orbital scenario, the laser spot size on the surface of Eros will vary from ~4-11m, and the along-track resolution for the nominal pulse repetition rate of 1 Hz will be approximately comparable to the spot size, resulting in contiguous along-track profiles. The across-track resolution will depend on the orbital mapping scenario, but will likely be <500m, which will define the spatial resolution of the global topographic model. Planned science investigations include global-scale analyses related to collisional and impact history and internal density distribution that utilize topographic grids as well as spherical harmonic topographic models that will be analyzed jointly with gravity at commensurate resolution. Attempts will be made to detect possible subtle time variations in internal structure that may be present if Eros is not a single coherent body, by analysis of low degree and order spherical harmonic coefficients. Local- to regional-scale analyses will utilize high-resolution three-dimensional topographic maps of specific surface structures to address surface geologic processes. Results from the NLR investigation will contribute significantly to understanding the origin, structure, and evolution of Eros and other asteroidal bodies.

Geological Map of the Fredegonade (V-57) Quadrangle, Venus: Status Report

NASA Technical Reports Server (NTRS)

Ivanov, M. A.; Head, J. W.

2010-01-01

The Fredegonde quadrangle (V-57; 50-75degS, 60-120degE, Fig. 1) corresponds to the northeastern edge of Lada Terra and covers a broad area of the topographic province of midlands (0-2 km above MPR [1,2]). This province is most abundant on Venus and displays a wide variety of units and structures [3-11]. The sequence of events that formed the characteristic features of the midlands is crucially important in understanding of the timing and modes of evolution of this topographic province. Topographically, the Fredegonde quadrangle is within a transition zone between the elevated portion of Lada Terra to the west (Quetzalpetlatl-Boala Coronae rise, approx.3.5 km) and the lowland of Aino Planitia to the north and northeast (approx.-0.5 km). This transition is one of the key features of the V-57 quadrangle. In this respect the quadrangle resembles the region of V-4 quadrangle [12] that shows transition between the midlands and the lowlands of Atalanta Planitia. One of the main goals of our mapping within the V-57 quadrangle is comparison of this region with the other transitional topographic zones such as quadrangles V-4 and V-3 [13]. The most prominent features in the V-57 quadrangle are linear deformational zones of grooves and large coronae. The zones characterize the central and NW portions of the map area and represent broad (up to 100s of km wide) ridges that are 100s of m high. Morphologically and topographically, these zones are almost identical to the groove belt/corona complexes at the western edge of Atalanta Planitia [12]. Within the Fredegonde area, however, the zones are oriented at high angles to the general trend of elongated Aino Planitia, whereas within the V-4 quadrangle they are parallel to the edge of Atalanta Planitia. Relatively small (100s of km across, 100s of m deep) equidimensional basins occur between the corona-groove-chains in the area of V-57 quadrangle. These basins are similar to those that populate the area of the V-3 quadrangle [13]. Broad regional plains cover the surface of the basins in both regions. In contrast to Fredegonde, the area of the V-3 quadrangle displays a greater diversity of units and features [13]. Here we describe units that make up the surface within the V-57 quadrangle and present a summary of our geological map that shows the areal distribution of the major groups of units.

Subsurface structures of buried features in the lunar Procellarum region

NASA Astrophysics Data System (ADS)

Wang, Wenrui; Heki, Kosuke

2017-07-01

The Gravity Recovery and Interior Laboratory (GRAIL) mission unraveled numbers of features showing strong gravity anomalies without prominent topographic signatures in the lunar Procellarum region. These features, located in different geologic units, are considered to have complex subsurface structures reflecting different evolution processes. By using the GRAIL level-1 data, we estimated the free-air and Bouguer gravity anomalies in several selected regions including such intriguing features. With the three-dimensional inversion technique, we recovered subsurface density structures in these regions.

Evaluating Topographic Effects on Ground Deformation: Insights from Finite Element Modeling

NASA Astrophysics Data System (ADS)

Ronchin, Erika; Geyer, Adelina; Martí, Joan

2015-07-01

Ground deformation has been demonstrated to be one of the most common signals of volcanic unrest. Although volcanoes are commonly associated with significant topographic relief, most analytical models assume the Earth's surface as flat. However, it has been confirmed that this approximation can lead to important misinterpretations of the recorded surface deformation data. Here we perform a systematic and quantitative analysis of how topography may influence ground deformation signals generated by a spherical pressure source embedded in an elastic homogeneous media and how these variations correlate with the different topographic parameters characterizing the terrain form (e.g., slope, aspect, curvature). For this, we bring together the results presented in previous published papers and complement them with new axisymmetric and 3D finite element (FE) model results. First, we study, in a parametric way, the influence of a volcanic edifice centered above the pressure source axis. Second, we carry out new 3D FE models simulating the real topography of three different volcanic areas representative of topographic scenarios common in volcanic regions: Rabaul caldera (Papua New Guinea) and the volcanic islands of Tenerife and El Hierro (Canary Islands). The calculated differences are then correlated with a series of topographic parameters. The final aim is to investigate the artifacts that might arise from the use of half-space models at volcanic areas due to diverse topographic features (e.g., collapse caldera structures, prominent central edifices, large landslide scars).

Tactile Earth and Space Science Materials for Students with Visual Impairments: Contours, Craters, Asteroids, and Features of Mars

ERIC Educational Resources Information Center

Rule, Audrey C.

2011-01-01

New tactile curriculum materials for teaching Earth and planetary science lessons on rotation=revolution, silhouettes of objects from different views, contour maps, impact craters, asteroids, and topographic features of Mars to 11 elementary and middle school students with sight impairments at a week-long residential summer camp are presented…

Three-Dimensional Structure of the Circulation Induced by a Shoaling Topographic Wave

NASA Astrophysics Data System (ADS)

Mizuta, G.; Hogg, N. G.

2003-12-01

Rectification of Rossby wave energy has been proposed as a mechanism for the maintenance of the recirculation cell of the Gulf Stream (Hogg 1988; Rizzoli et al. 1995). We investigated the three-dimensional structure of potential-vorticity flux and a mean flow induced by a topographic wave incident over a bottom slope analytically and numerically, focusing on the limit that bottom friction is the dominant dissipation process. In this limit it is shown that the topographic wave cannot be a steady source of the potential vorticity outside the bottom Ekman layer. Instead, the distribution of potential vorticity is determined from the initial transient of the topographic wave. This potential vorticity and the heat flux by the topographic wave at the bottom determine the mean flow, and give a relation between the horizontal and vertical scales of the mean flow. When the horizontal scale of the mean flow is larger than the internal deformation radius, the mean flow is almost constant with depth independent of whether or not the topographic wave is trapped near the bottom. Then the mean flow at the bottom is proportional to the divergence of vertically integrated Reynolds stress ∫ -D0 /line{u'v'} dz. This divergence, which is caused by bottom friction, is large when the group velocity, cg and the vertical scale, μ -1 of the wave motion are small. Thus the mean flow tends to be large where cg and μ -1 become small, and decreases as the topographic wave is dissipated by bottom friction. Since bottom friction also dissipates the mean flow, the mean flow asymptotes to a constant value as the friction becomes zero. These features of the potential-vorticity flux and the mean flow are reproduced in numerical experiments. It is also shown from the numerical experiment that the distribution of the mean flow depends on the amplitude of the wave because of the Doppler shift of the wave by the mean flow. These feature of the mean flow are preserved when we used stratification and bottom topography resembling to those over the continental slope near the Gulf Stream. The transport of the mean flow is about 20 Sv when the wave amplitude is about 2 cm/s. These numbers are similiar to those observed in the Gulf Stream region.

[The application of wavelet analysis of remote detection of pollution clouds].

PubMed

Zhang, J; Jiang, F

2001-08-01

The discrete wavelet transform (DWT) is used to analyse the spectra of pollution clouds in complicated environment and extract the small-features. The DWT is a time-frequency analysis technology, which detects the subtle small changes in the target spectrum. The results show that the DWT is a quite effective method to extract features of target-cloud and improve the reliability of monitoring alarm system.

43 CFR 23.7 - Approval of exploration plan.

Code of Federal Regulations, 2010 CFR

2010-10-01

... showing topographic, cultural and drainage features; (3) A statement of proposed exploration methods, i.e... measures to be taken to prevent or control fire, soil erosion, pollution of surface and ground water...

SPOT-VEG Based Analysis of Siberian Silkmoth Outbreak

NASA Technical Reports Server (NTRS)

Kharuk, Viatcheslav I.; Ranson, K. Jon; Im. Sergey T.

2007-01-01

The spatial and temporal dynamics of an outbreak of the Siberian silkmoth were correlated with topographic features of the affected area using SPOT-VEG data and a high resolution digital elevation model (DEM). In 2002-2003 an outbreak affected approximately 20,000 ha in the South Siberian mountains of Russia. The outbreak began between the elevations of approximately 430- 480 m and on southwest slopes with steepness < 5 degrees. As the pest searched for food it moved up and down slope, resulting in an elevation distribution split within a range of approximately 390-540 m and slope steepness up to 15 degrees. In the final phase the azimuth distribution of damaged stands became even. The correlation between the initial phase and topographic features can be used to prioritize monitoring forest areas most vulnerable to destruction by pests.

Using terrestrial radar to explore lava channel erosion on Momotombo volcano, Nicaragua

NASA Astrophysics Data System (ADS)

Gallant, E.; Deng, F.; Xie, S.; Connor, L.; Connor, C.; Saballos, J. A.; Dixon, T. H.; Myhre, D.

2017-12-01

We explore the application of terrestrial radar as a tool for imaging topography on Momotombo volcano, Nicaragua. A major feature of the edifice is an incised lava flow channel (possibly created by the 1904 eruption) that measures 150m in width and up to 60m in depth. This feature is unusual because most lava channels are constructional in nature and constrained by levees on their margins. The radar elevation model was used alongside a TerraSAR-X/TanDEM-X DEM to help create a topographic time series. We consider the possibility that the channel was formed during the 1904 eruption by thermal and / or mechanical erosion. We aim to quantify the energy required to create the observed topography by merging this topographic time series with existing field observations and mathematical models of erosion via lava flow.

Cellular Scale Anisotropic Topography Guides Schwann Cell Motility

PubMed Central

Mitchel, Jennifer A.; Hoffman-Kim, Diane

2011-01-01

Directed migration of Schwann cells (SC) is critical for development and repair of the peripheral nervous system. Understanding aspects of motility specific to SC, along with SC response to engineered biomaterials, may inform strategies to enhance nerve regeneration. Rat SC were cultured on laminin-coated microgrooved poly(dimethyl siloxane) platforms that were flat or presented repeating cellular scale anisotropic topographical cues, 30 or 60 µm in width, and observed with timelapse microscopy. SC motion was directed parallel to the long axis of the topography on both the groove floor and the plateau, with accompanying differences in velocity and directional persistence in comparison to SC motion on flat substrates. In addition, feature dimension affected SC morphology, alignment, and directional persistence. Plateaus and groove floors presented distinct cues which promoted differential motility and variable interaction with the topographical features. SC on the plateau surfaces tended to have persistent interactions with the edge topography, while SC on the groove floors tended to have infrequent contact with the corners and walls. Our observations suggest the capacity of SC to be guided without continuous contact with a topographical cue. SC exhibited a range of distinct motile morphologies, characterized by their symmetry and number of extensions. Across all conditions, SC with a single extension traveled significantly faster than cells with more or no extensions. We conclude that SC motility is complex, where persistent motion requires cellular asymmetry, and that anisotropic topography with cellular scale features can direct SC motility. PMID:21949703

An assessment of two methods for identifying undocumented levees using remotely sensed data

USGS Publications Warehouse

Czuba, Christiana R.; Williams, Byron K.; Westman, Jack; LeClaire, Keith

2015-01-01

Many undocumented and commonly unmaintained levees exist in the landscape complicating flood forecasting, risk management, and emergency response. This report describes a pilot study completed by the U.S. Geological Survey in cooperation with the U.S. Army Corps of Engineers to assess two methods to identify undocumented levees by using remotely sensed, high-resolution topographic data. For the first method, the U.S. Army Corps of Engineers examined hillshades computed from a digital elevation model that was derived from light detection and ranging (lidar) to visually identify potential levees and then used detailed site visits to assess the validity of the identifications. For the second method, the U.S. Geological Survey applied a wavelet transform to a lidar-derived digital elevation model to identify potential levees. The hillshade method was applied to Delano, Minnesota, and the wavelet-transform method was applied to Delano and Springfield, Minnesota. Both methods were successful in identifying levees but also identified other features that required interpretation to differentiate from levees such as constructed barriers, high banks, and bluffs. Both methods are complementary to each other, and a potential conjunctive method for testing in the future includes (1) use of the wavelet-transform method to rapidly identify slope-break features in high-resolution topographic data, (2) further examination of topographic data using hillshades and aerial photographs to classify features and map potential levees, and (3) a verification check of each identified potential levee with local officials and field visits.

Understanding volcanic geomorphology from derivatives and wavelet analysis: A case study at Miyakejima Volcano, Izu Islands, Japan

NASA Astrophysics Data System (ADS)

Gomez, C.

2018-04-01

From feature recognition to multiscale analysis, the human brain does this computation almost instantaneously, but reproducing this process for effective computation is still a challenge. Although it is a growing field in computational geomorphology, there has been only limited investigation of those issues on volcanoes. For the present study, we investigated Miyakejima, a volcanic island in the Izu archipelago, located 200 km south of Tokyo City (Japan). The island has experienced numerous Quaternary and historical eruptions, which have been recorded in details and therefore provide a solid foundation to experiment remote-sensing methods and compare the results to existing data. In the present study, the author examines the use of DEM derivatives and wavelet decomposition 5 m DEM available from the Geographic Authority of Japan was used. It was pre-processed to generate grid data with QGIS. The data was then analyzed with remote sensing techniques and wavelet analysis in ENVI and Matlab. Results have shown that the combination of 'Elevation' with 'Local Data Range Variation' and 'Relief Mapping' as a RGB image composite provides a powerful visual interpretation tool, but the feature separation remains a subjective analysis provided a more appropriate dataset for computer-based analysis and information extraction and understanding of topographic features at different scales. In order to confirm the usefulness of these topographic derivatives, the results were compared to known geological features and it was found to be in accordance with the data provided by geological, topographic maps and field research at Miyakejima. The protocol presented in the discussion can therefore be re-used at other volcanoes worldwide where less information is available on past-eruption and geology, in order to explain the volcanic geomorphology.

Creation of next generation U.S. Geological Survey topographic maps

USGS Publications Warehouse

Craun, Kari J.

2010-01-01

The U.S. Geological Survey (USGS) is 2 years into a 3-year cycle to create new digital topographic map products for the conterminous United States from data acquired and maintained as part of The National Map databases. These products are in the traditional, USGS topographic quadrangle, 7.5-minute (latitude and longitude) cell format. The 3-year cycle was conceived to follow the acquisition of National Aerial Imagery Program (NAIP) orthorectified imagery, a key layer in the new product. In fiscal year (FY) 2009 (ending September 30, 2009), the first year of the 3-year cycle, the USGS produced 13,200 products. These initial products of the “Digital MapBeta” series had limited feature content, including only the NAIP image, some roads, geographic names, and grid and collar information. The products were created in layered georegistered Portable Document Format (PDF) files, allowing users with freely available Adobe® Reader® software to view, print, and perform simple Geographic Information System-like functions. In FY 2010 (ending September 30, 2010), the USGS produced 20,380 products. These products of the “US Topo” series added hydrography (surface water features), contours, and some boundaries. In FY 2011 (ending September 30, 2011), the USGS will complete the initial coverage with US Topo products and will add additional feature content to the maps. The design, development, and production associated with the US Topo products provide management and technical challenges for the USGS and its public and private sector partners. One challenge is the acquisition and maintenance of nationally consistent base map data from multiple sources. Another is the use of these data to create a consistent, current series of cartographic products that can be used by the broad spectrum of traditional topographic map users. Although the USGS and its partners have overcome many of these challenges, many, such as establishing and funding a sustainable base data-maintenance program, remain to be resolved for the long term.

Derivation of Ground Surface and Vegetation in a Coastal Florida Wetland with Airborne Laser Technology

USGS Publications Warehouse

Raabe, Ellen A.; Harris, Melanie S.; Shrestha, Ramesh L.; Carter, William E.

2008-01-01

The geomorphology and vegetation of marsh-dominated coastal lowlands were mapped from airborne laser data points collected on the Gulf Coast of Florida near Cedar Key. Surface models were developed using low- and high-point filters to separate ground-surface and vegetation-canopy intercepts. In a non-automated process, the landscape was partitioned into functional landscape units to manage the modeling of key landscape features in discrete processing steps. The final digital ground surface-elevation model offers a faithful representation of topographic relief beneath canopies of tidal marsh and coastal forest. Bare-earth models approximate field-surveyed heights by + 0.17 m in the open marsh and + 0.22 m under thick marsh or forest canopy. The laser-derived digital surface models effectively delineate surface features of relatively inaccessible coastal habitats with a geographic coverage and vertical detail previously unavailable. Coastal topographic details include tidal-creek tributaries, levees, modest topographic undulations in the intertidal zone, karst features, silviculture, and relict sand dunes under coastal-forest canopy. A combination of laser-derived ground-surface and canopy-height models and intensity values provided additional mapping capabilities to differentiate between tidal-marsh zones and forest types such as mesic flatwood, hydric hammock, and oak scrub. Additional derived products include fine-scale shoreline and topographic profiles. The derived products demonstrate the capability to identify areas of concern to resource managers and unique components of the coastal system from laser altimetry. Because the very nature of a wetland system presents difficulties for access and data collection, airborne coverage from remote sensors has become an accepted alternative for monitoring wetland regions. Data acquisition with airborne laser represents a viable option for mapping coastal topography and for evaluating habitats and coastal change on marsh-dominated coasts. Such datasets can be instrumental in effective coastal-resource management.

[Extended endoscopic endonasal posterior (transclival) approach to tumors of the clival region and ventral posterior cranial fossa. Part 1. Topographic and anatomical features of the clivus and adjacent structures].

PubMed

Shkarubo, A N; Koval', K V; Dobrovol'skiy, G F; Shkarubo, M A; Karnaukhov, V V; Kadashev, B A; Andreev, D N; Chernov, I V; Gadzhieva, O A; Aleshkina, O Yu; Anisimova, E A; Kalinin, P L; Kutin, M A; Fomichev, D V; Sharipov, O I; Ismailov, D B; Selivanov, E S

to describe the main topographic and anatomical features of the clival region and its adjacent structures for improvement and optimization of the extended endoscopic endonasal posterior (transclival) approach for resection of tumors of the clival region and ventral posterior cranial fossa. We performed a craniometric study of 125 human skulls and a topographic anatomical study of heads of 25 cadavers, the arterial and venous bed of which was stained with colored silicone (the staining technique was developed by the authors) to visualize bed features and individual variability. Currently, we have clinical material from more than 120 surgical patients with various skull base tumors of the clival region and ventral posterior cranial fossa (chordomas, pituitary adenomas, meningiomas, cholesteatomas, etc.) who were operated on using the endoscopic transclival approach. We present the main anatomical landmarks and parameters of some anatomical structures that are required for performing the endoscopic endonasal posterior approach. The anatomical landmarks, such as the intradural openings of the abducens and glossopharyngeal nerves, may be used to arbitrarily divide the clival region into the superior, middle, and inferior thirds. The anatomical landmarks important for the surgeon, which are detected during a topographic anatomical study of the skull base, facilitate identification of the boundaries between the different clival portions and the C1 segments of the internal carotid arteries. The superior, middle, and inferior transclival approaches provide an access to the ventral surface of the upper, middle, and lower neurovascular complexes in the posterior cranial fossa. The endoscopic transclival approach may be used to access midline tumors of the posterior cranial fossa. The approach is an alternative to transcranial approaches in surgical treatment of clival region lesions. This approach provides results comparable (and sometimes better) to those of the transcranial and transfacial approaches.

Kinematic Evolution of the North-Tehran Fault (NTF), Alborz Mountains, Iran

NASA Astrophysics Data System (ADS)

Landgraf, A.; Ballato, P.; Strecker, M. R.; Shahpasandzadeh, M.; Friedrich, A.; Tabatabaei, S. H.

2007-12-01

The ENE-to NW-striking NTF is an active frontal thrust that delimits the Alborz Mountain range to the south with an up to 2000 m topographic break with respect to the adjacent Tehran plain. Eocene rocks of the Alborz range are thrusted over Neogene and Quaternary sediments of the alluvial Tehran embayment. The fault consists of right- stepping segments and merges to the east with the active Mosha-Fasham strike-slip fault (MFF). The complex tectonic history, involving changes in the direction of SHmax, has resulted in a composite tectonic landscape with inherited topographic and fault-kinematic fingerprints along the NTF. We therefore used a combination of fault-kinematic measurements and geomorphic observations to unravel the temporal tectonic evolution of this fault. Presently, the NTF is virtually inactive, although the tectonically overprinted landforms reflect tectonic activity on longer time scales during the Quaternary. Being located adjacent north of the Tehran megacity, there is thus considerable interest to decipher its youngest tectonic evolution and to better understand the relation with other fault systems. Our fault kinematic study has revealed an early dextral kinematic history for the NTF. Dextral strike-slip and oblique reverse faulting took place during NW-oriented shortening. The overall fault-geometry of the NTF suggests that it has evolved in relation to dextral transpression along the MFF. This early kinematic regime was superseded by NE-oriented shortening, associated with sinistral-oblique thrusting along the fault segments. Fault linkage between the semi-independent ENE-striking NTF-segments and NW-striking thrusts (Emamzadeh Davud Fault [EDF], Purkan Vardij Thrust [PVT], NTF-prolongation) point towards an evolution into a nascent transpressional duplex. In this scenario the NTF segments constitute lateral ramps and the NW-striking faults act as frontal ramps. Topographic residuals, as an expression of high-uplift zones, indicate that the central segment of the NTF, incorporating the EDF was most effective in accommodating oblique convergence during this time. However, subtle knickpoints in the longitudinal river profiles crossing the PVT may indicate a relatively recent transfer of deformation onto this block. The youngest manifestations of deformation along the NTF, however, are left-lateral and normal faulting. This youngest phase of activity is documented by numerous striated and rotated conglomeratic clasts, meter-scale fault gouge zones with shear-sense indicators of oblique normal faulting, and multiple colluvial wedges with drag phenomena. Rupture traces and filled extensional cracks reaching the surface also document the seismogenic nature of these features. Since recent left-lateral transtension is also known from neighboring faults, e.g., the eastern MFF, our observations suggest that this youngest phase of tectonic activity of the NTF is a regional phenomenon, rather than the result of locally-determined geometries.

Complex, multi-scale small intestinal topography replicated in cellular growth substrates fabricated via chemical vapor deposition of Parylene C.

PubMed

Koppes, Abigail N; Kamath, Megha; Pfluger, Courtney A; Burkey, Daniel D; Dokmeci, Mehmet; Wang, Lin; Carrier, Rebecca L

2016-08-22

Native small intestine possesses distinct multi-scale structures (e.g., crypts, villi) not included in traditional 2D intestinal culture models for drug delivery and regenerative medicine. The known impact of structure on cell function motivates exploration of the influence of intestinal topography on the phenotype of cultured epithelial cells, but the irregular, macro- to submicron-scale features of native intestine are challenging to precisely replicate in cellular growth substrates. Herein, we utilized chemical vapor deposition of Parylene C on decellularized porcine small intestine to create polymeric intestinal replicas containing biomimetic irregular, multi-scale structures. These replicas were used as molds for polydimethylsiloxane (PDMS) growth substrates with macro to submicron intestinal topographical features. Resultant PDMS replicas exhibit multiscale resolution including macro- to micro-scale folds, crypt and villus structures, and submicron-scale features of the underlying basement membrane. After 10 d of human epithelial colorectal cell culture on PDMS substrates, the inclusion of biomimetic topographical features enhanced alkaline phosphatase expression 2.3-fold compared to flat controls, suggesting biomimetic topography is important in induced epithelial differentiation. This work presents a facile, inexpensive method for precisely replicating complex hierarchal features of native tissue, towards a new model for regenerative medicine and drug delivery for intestinal disorders and diseases.

UAV-based remote sensing surveys of lava flow fields: a case study from Etna's 1974 channel-fed lava flows

NASA Astrophysics Data System (ADS)

Favalli, Massimiliano; Fornaciai, Alessandro; Nannipieri, Luca; Harris, Andrew; Calvari, Sonia; Lormand, Charline

2018-03-01

During an eruption, time scales of topographic change are fast and involve vertical and planimetric evolution of millimeters to meters as the event progresses. Repeat production of high spatial resolution terrain models of lava flow fields over time scales of a few hours is thus a high-value capability in tracking the buildup of the deposit. Among the wide range of terrestrial and aerial methods available to collect such topographic data, the use of an unmanned aerial vehicle (UAV) as an acquisition platform, together with structure from motion (SfM) photogrammetry, has become especially useful. This approach allows high-frequency production of centimeter-scale terrain models over kilometer-scale areas, including dangerous and inaccessible zones, with low cost and minimal hazard to personnel. This study presents the application of such an integrated UAV-SfM method to generate a high spatial resolution digital terrain model and orthomosaic of Mount Etna's January-February 1974 lava flow field. The SfM method, applied to images acquired using a UAV platform, enabled the extraction of a very high spatial resolution (20 cm) digital elevation model and the generation of a 3-cm orthomosaic covering an area of 1.35 km2. This spatial resolution enabled us to analyze the morphology of sub-meter-scale features, such as folds, blocks, and cracks, over kilometer-scale areas. The 3-cm orthomosaic allowed us to further push the analysis to centimeter-scale grain size distribution of the lava surface. Using these data, we define three types of crust structure and relate them to positions within a channel-fed ´áā flow system. These crust structures are (i) flow parallel shear lines, (ii) raft zones, and (iii) folded zones. Flow parallel shear lines are found at the channel edges, and are 2-m-wide and 0.25-m-deep zones running along the levee base and in which cracking is intense. They result from intense shearing between the moving channel lava and the static levee lava. In zones where initial levees are just beginning to form, these subtle features are the only marker that delimits the moving lava from the stagnant marginal lava. Rafts generally form as the system changes from a stable to a transitional channel regime. Over this 170-m-long zone, the channel broadens from 8 to 70 m and rafts are characterized by topographically higher and poorly cracked areas, surrounded by lower, heavily cracked areas. We interpret the rafts as forming due to breakup of crust zones, previously moving in a coherent manner in the narrow proximal channel reach. Folded zones involve arcuate, cross-flow ridges with their apexes pointing down-flow, where ridges have relatively small clasts and depressions are of coarser-grained breccia. Our folds have wavelengths of 10 m and amplitudes of 1 m; are found towards the flow front, down-flow of the raft zones; and are associated with piling up of lava behind a static or slowly moving flow front. The very high spatial resolution topographic data available from UAV-SfM allow us to resolve surfaces where roughness has a vertical and horizontal scale of variation that is less than 1 m. This is the case over pāhoehoe and ´áā flow surfaces, and thus allows us to explore those new structures that are only apparent in the sub-metric data. Moreover, during future eruptions, the possibility to acquire such information in near-real time will allow a prompt analysis of developing lava flow fields and structures therein, such as developing lava channel systems, so as to contribute to timely hazard assessment, modeling, and projections.

TOPEX watershed coming in oceanography

NASA Technical Reports Server (NTRS)

Cleven, G. C.; Neilson, R. A.; Yamarone, C. A., Jr.

1983-01-01

The NASA Ocean Topography Experiment (TOPEX) will use precision radar altimetry to determine topographic features of the global oceans from which currents may be deduced. TOPEX will coincide with the World Ocean Circulation Experiment (WOCE), which will be conducted at the end of this decade and shall involve ships, fixed and drifting buoys, aircraft observations, and satellite remote sensing, to resolve fundamental questions about the flow of water in the global ocean. TOPEX will contribute to WOCE the measurement of satellite height above the sea surface, and the precise radial position above a reference ellipsoid for the earth. The combination of these two measurements with the marine geoid yields the topographic data sought. Three years of topographic data, together with conventional oceanographic data and theoretical ocean models, will be needed to derive the mean and variable components of ocean circulation.

Venus - False Color Image of Alpha Regio

NASA Image and Video Library

1996-02-07

NASA's Magellan radar image shows Alpha Regio, a topographic upland. In 1963 Alpha Regio was the first feature on Venus to be identified from Earth based radar. http://photojournal.jpl.nasa.gov/catalog/PIA00147

Neural representations of emotion are organized around abstract event features.

PubMed

Skerry, Amy E; Saxe, Rebecca

2015-08-03

Research on emotion attribution has tended to focus on the perception of overt expressions of at most five or six basic emotions. However, our ability to identify others' emotional states is not limited to perception of these canonical expressions. Instead, we make fine-grained inferences about what others feel based on the situations they encounter, relying on knowledge of the eliciting conditions for different emotions. In the present research, we provide convergent behavioral and neural evidence concerning the representations underlying these concepts. First, we find that patterns of activity in mentalizing regions contain information about subtle emotional distinctions conveyed through verbal descriptions of eliciting situations. Second, we identify a space of abstract situation features that well captures the emotion discriminations subjects make behaviorally and show that this feature space outperforms competing models in capturing the similarity space of neural patterns in these regions. Together, the data suggest that our knowledge of others' emotions is abstract and high dimensional, that brain regions selective for mental state reasoning support relatively subtle distinctions between emotion concepts, and that the neural representations in these regions are not reducible to more primitive affective dimensions such as valence and arousal. Copyright © 2015 Elsevier Ltd. All rights reserved.

An Energy-Based Approach for Detection and Characterization of Subtle Entities Within Laser Scanning Point-Clouds

NASA Astrophysics Data System (ADS)

Arav, Reuma; Filin, Sagi

2016-06-01

Airborne laser scans present an optimal tool to describe geomorphological features in natural environments. However, a challenge arises in the detection of such phenomena, as they are embedded in the topography, tend to blend into their surroundings and leave only a subtle signature within the data. Most object-recognition studies address mainly urban environments and follow a general pipeline where the data are partitioned into segments with uniform properties. These approaches are restricted to man-made domain and are capable to handle limited features that answer a well-defined geometric form. As natural environments present a more complex set of features, the common interpretation of the data is still manual at large. In this paper, we propose a data-aware detection scheme, unbound to specific domains or shapes. We define the recognition question as an energy optimization problem, solved by variational means. Our approach, based on the level-set method, characterizes geometrically local surfaces within the data, and uses these characteristics as potential field for minimization. The main advantage here is that it allows topological changes of the evolving curves, such as merging and breaking. We demonstrate the proposed methodology on the detection of collapse sinkholes.

Neural Representations of Emotion Are Organized around Abstract Event Features

PubMed Central

Skerry, Amy E.; Saxe, Rebecca

2016-01-01

Summary Research on emotion attribution has tended to focus on the perception of overt expressions of at most five or six basic emotions. However, our ability to identify others' emotional states is not limited to perception of these canonical expressions. Instead, we make fine-grained inferences about what others feel based on the situations they encounter, relying on knowledge of the eliciting conditions for different emotions. In the present research, we provide convergent behavioral and neural evidence concerning the representations underlying these concepts. First, we find that patterns of activity in mentalizing regions contain information about subtle emotional distinctions conveyed through verbal descriptions of eliciting situations. Second, we identify a space of abstract situation features that well captures the emotion discriminations subjects make behaviorally and show that this feature space outperforms competing models in capturing the similarity space of neural patterns in these regions. Together, the data suggest that our knowledge of others' emotions is abstract and high dimensional, that brain regions selective for mental state reasoning support relatively subtle distinctions between emotion concepts, and that the neural representations in these regions are not reducible to more primitive affective dimensions such as valence and arousal. PMID:26212878

Mineralogical Composition and Potential Dust Source of Playas in the Western U.S. and Australia as Remotely Identified Through Imaging Spectroscopy.

NASA Astrophysics Data System (ADS)

Raming, L. W.; Farrand, W. H.; Bowen, B.

2015-12-01

Playas are significant dust sources and as a result are potentially hazardous to human health. The composition of the dust is a function of the mineralogical content of the playa and associated brines. Playas are found in arid climates globally, however they are challenging to map geologically as they are often hard to access, have subtle variations in mineralogy, and are topographically featureless. This study uses remote sensing in the form of imaging spectroscopy to map the mineralogical composition of five playas from different geologic settings: Railroad Valley Playa, Nevada, USA; Bonneville Salt Flats, Utah, USA; White Sands National Monument, New Mexico, USA; Lake Brown, Western Australia, Australia; and Lake Tyrrell, Victoria, Australia.Multiple spectrometers were used for this study; these include the multispectral sensor ASTER, and the hyperspectral sensors AVIRIS, HICO, and HyMap. All scenes were processed in ENVI and corrected to at surface reflectance using FLAASH, QUAC or Empirical Line methods. Minerals were identified through a standard end-member extraction approach and mapped using multi-range spectral feature fitting and other methods. Additionally, remote data are combined with in-situ field-based spectra and sample-based laboratory spectra.Initial results suggest various and differing mineralogy between playas. The most abundant mineralogy includes clay minerals such as illite and montmorillonite and evaporites such as gypsum. Additionally there has been identification of Fe absorption bands in the visible / near infrared at White Sands National Monument, and Lake Brown and Lake Tyrell, suggesting the presence of iron bearing minerals. Further research will provide a more comprehensive list of minerals identified by absorption features as related to specific sensors. Collectively, these analyses will be used characterize overall patterns in playa surface mineralogy and to evaluate the parameters that influence playa dust source composition.

Testing the role of bedforms as controls on the morphodynamics of sandy braided rivers with CFD

NASA Astrophysics Data System (ADS)

Unsworth, C. A.; Nicholas, A. P.; Ashworth, P. J.; Best, J.; Lane, S. N.; Parsons, D. R.; Sambrook Smith, G.; Simpson, C.; Strick, R. J. P.

2017-12-01

Sand-bed rivers are characterised by multiple scales of topography (e.g., channels, bars and bedforms). Small scale topographic features (e.g., dunes) exert a significant influence on coherent flow structures and sediment transport processes, over distances that scale with channel depth. However, the extent to which such dune-scale effects control larger, channel and bar-scale morphology and morphodynamics remains unknown. Moreover, such bedform effects are typically neglected in two-dimensional (depth-averaged) morphodynamic models that are used to simulate river evolution. To evaluate the significance of these issues, we report results from a combined numerical modelling and field monitoring study, undertaken in the South Saskatchewan River, Canada. Numerical simulations were carried out, using the OpenFOAM CFD code, to quantify the mean three-dimensional flow structure within a 90 x 350 m section of channel. To isolate the role of bedforms as a control on flow and sediment transport, two simulations were undertaken. The first used a high-resolution ( 3 cm) bedform-resolving DEM. The second used a filtered DEM in which dunes were removed and only large scale topographic features (e.g., bars, scour pools etc) were resolved. The results of these simulations are compared here, in order to quantify the degree to which topographic steering by bedforms influences flow and sediment transport directions at bar and channel scales. Analysis of the CFD simulation results within a 2D morphodynamic modelling framework demonstrates that dunes exert a significant influence on sediment transport, and hence morphodynamics, and highlights important shortcomings in existing 2D model parameterisations of topographic steering.

Topographic Evidence for Eruptive Style Changes and Magma Evolution of Small Plains-style Volcanoes on Earth and Mars

NASA Technical Reports Server (NTRS)

Hughes, S. S.; Sakimoto, S. E.H.; Gregg, T. K. P.; Chadwick, D. J.; Brady, S. B.; Farley, M. A.; Holmes, A. A. .; Semple, A. M.; Weren, S.L.

2004-01-01

Topographic profiles and surface characteristics of small (5 - 25 km diameter) plains-style shield volcanoes on the eastern Snake River Plain (ESRP) provide a method to evaluate eruptive processes and magmatic evolution on Martian volcanic plains. The ESRP is an ideal place to observe Mars-like volcanic features where hundreds of small monogenetic basaltic shields dominate the volcanic-sedimentary depositional sequence, and numerous planetary analogues are evident: coalescent mafic shields, hydromagmatic explosive eruptions, the interaction of lava flows with surficial water and glacial ice, and abundant eolian sand and loess. Single flows cannot be correlated over great distances, and are spatially restricted. These relations are useful for planetary exploration when inferring volcanic evolutionary patterns in lava plains represented by numerous eruptive vents. High spatial resolution imagery and digital topographic data for Mars from MOC, MOLA, and THEMIS is allowing for improvements in the level of detail of stratigraphic mapping of fields of small (< 25 km in diameter) volcanoes as well as studies of the morphological characteristics of individual volcanoes. In order to compare Mars and Earth volcanic features, elevation data from U.S.G.S. 10-meter digital elevation models (DEMs) and high-precision GPS field measurements are used in this study to generate approx. 20m spacing topographic profiles from which slope and surface morphology can be extracted. Average ESRP flank and crater slopes are calculated using 100 - 200 m spacing for optimum comparison to MOLA data, and to reduce the effects of surface irregularities.

Population Distribution Analyses Reveal a Hierarchy of Molecular Players Underlying Parallel Endocytic Pathways

PubMed Central

Gupta, Gagan D.; Howes, Mark T.; Chandran, Ruma; Das, Anupam; Menon, Sindhu; Parton, Robert G.; Sowdhamini, R.; Thattai, Mukund; Mayor, Satyajit

2014-01-01

Single-cell-resolved measurements reveal heterogeneous distributions of clathrin-dependent (CD) and -independent (CLIC/GEEC: CG) endocytic activity in Drosophila cell populations. dsRNA-mediated knockdown of core versus peripheral endocytic machinery induces strong changes in the mean, or subtle changes in the shapes of these distributions, respectively. By quantifying these subtle shape changes for 27 single-cell features which report on endocytic activity and cell morphology, we organize 1072 Drosophila genes into a tree-like hierarchy. We find that tree nodes contain gene sets enriched in functional classes and protein complexes, providing a portrait of core and peripheral control of CD and CG endocytosis. For 470 genes we obtain additional features from separate assays and classify them into early- or late-acting genes of the endocytic pathways. Detailed analyses of specific genes at intermediate levels of the tree suggest that Vacuolar ATPase and lysosomal genes involved in vacuolar biogenesis play an evolutionarily conserved role in CG endocytosis. PMID:24971745

An Example of Unsupervised Networks Kohonen's Self-Organizing Feature Map

NASA Technical Reports Server (NTRS)

Niebur, Dagmar

1995-01-01

Kohonen's self-organizing feature map belongs to a class of unsupervised artificial neural network commonly referred to as topographic maps. It serves two purposes, the quantization and dimensionality reduction of date. A short description of its history and its biological context is given. We show that the inherent classification properties of the feature map make it a suitable candidate for solving the classification task in power system areas like load forecasting, fault diagnosis and security assessment.

Idiopathic ophthalmodynia and idiopathic rhinalgia: two topographic facial pain syndromes.

PubMed

Pareja, Juan A; Cuadrado, María L; Porta-Etessam, Jesús; Fernández-de-las-Peñas, César; Gili, Pablo; Caminero, Ana B; Cebrián, José L

2010-09-01

To describe 2 topographic facial pain conditions with the pain clearly localized in the eye (idiopathic ophthalmodynia) or in the nose (idiopathic rhinalgia), and to propose their distinction from persistent idiopathic facial pain. Persistent idiopathic facial pain, burning mouth syndrome, atypical odontalgia, and facial arthromyalgia are idiopathic facial pain syndromes that have been separated according to topographical criteria. Still, some other facial pain syndromes might have been veiled under the broad term of persistent idiopathic facial pain. Through a 10-year period we have studied all patients referred to our neurological clinic because of facial pain of unknown etiology that might deviate from all well-characterized facial pain syndromes. In a group of patients we have identified 2 consistent clinical pictures with pain precisely located either in the eye (n=11) or in the nose (n=7). Clinical features resembled those of other localized idiopathic facial syndromes, the key differences relying on the topographic distribution of the pain. Both idiopathic ophthalmodynia and idiopathic rhinalgia seem specific pain syndromes with a distinctive location, and may deserve a nosologic status just as other focal pain syndromes of the face. Whether all such focal syndromes are topographic variants of persistent idiopathic facial pain or independent disorders remains a controversial issue.

Subtle imitation behaviour in convenience samples of normal, demented, and currently depressed elderly subjects.

PubMed

von Gunten, Armin; Duc, René

2007-06-01

The clinical significance of imitation behaviour (IB) is unclear. The aim of this study was to investigate the prevalence of subtle naïve and obstinate IB in convenience samples of normal elderly, demented, and depressed subjects. Subtle IB was assessed using a protocol constructed ad hoc in 146 patients, consecutively referred to a memory clinic having received an ICD-10 diagnosis of either dementia or depression, and in 241 healthy subjects. The prevalence of IB in the three groups was determined and the association with possible demographic, cognitive, and non-cognitive variables analysed. Subtle naïve IB was frequent in the elderly with dementia, intermediate in the depressed, and rare in the normal elderly except that the latter frequently stretched out their arms. Obstinate IB never occurred in the normal elderly. IB was predicted by none of the variables used. The groups included were convenience samples with the depressed being a small group precluding further distinction of depressive subtypes. Although naïve IB is a frequent clinical feature in the demented, it also accompanies depressive disorders in the elderly. It can be observed as context-specific IB in the normal elderly. Obstinate IB does not occur in the normal elderly. Copyright 2006 John Wiley & Sons, Ltd.

Microwave brightness temperature features of lunar craters: observation from Chang'E-1 mission

NASA Astrophysics Data System (ADS)

Hu, Guo-Ping; Chen, Ke; Guo, Wei; Li, Qing-Xia; Su, Hong-Yan

2013-01-01

Topographic features of lunar craters have been found from the brightness temperature (TB) observed by the multichannel (3.0, 7.8, 19.35, and 37 GHz) microwave radiometer (MRM) aboard Chang'E-1 (CE-1) in a single track view. As the topographic effect is more obvious at 37 GHz, 37 GHz TB has been focused on in this work. The variation of 37 GHz daytime (nighttime) TB along the profile of a crater is found to show an oscillatory behavior. The amplitude of daytime TB is significantly affected by the observation time and the shape of the crater, whose diameter is bigger than the spatial resolution of MRM onboard CE-1. The large and typical diurnal TB difference (nighttime TB minus daytime TB) at 37 GHz over selected young craters due to the large rock abundance in craters, have been discussed and compared with the altitude profile.

Topography of the Northern Hemisphere of Mercury from MESSENGER Laser Altimetry

NASA Technical Reports Server (NTRS)

Zuber,Maria T.; Smith, David E.; Phillips, Roger J.; Solomon, Sean C.; Neumann, Gregory A.; Hauck, Steven A., Jr.; Peale, Stanton J.; Barnouin, Oliver S.; Head, James W.; Johnson, Catherine L.;

Gold occurrences in the Greenville 1 degree by 2 degrees Quadrangle, South Carolina, Georgia, and North Carolina

USGS Publications Warehouse

D'Agostino, John P.; Mason, George T.; Zupan, Alan J.W.; Maybin, Arthur H.; German, Jerry M.; Abrams, Charlotte E.

1994-01-01

All of the gold mines, prospects, placers, and occurrences known in the Greenville 1° x 2° quadrangle are tabulated in this report. The table lists, in consecutive order by county (fig. 1), the map number of each feature, which is located either on the accompanying Greenville 1° x 2° quadrangle map or figure 2. The known name of the feature; the 7.5' topographic map on the which the gold site is located (if known, within 25 ft or 7.6 m), the Universal Transverse Mercator (UTM) northing and easting grid coordinates from the appropriate 7.5' topographic map; the commodity; remarks; and references are also listed. Some locations are known, but many sites are not verified and their locations are only approximate. References are listed in References Cited and referred to by number to save space.

Occupancy of the Invasive Feral Cat Varies with Habitat Complexity

PubMed Central

Hohnen, Rosemary; Tuft, Katherine; McGregor, Hugh W.; Legge, Sarah; Radford, Ian J.; Johnson, Christopher N.

2016-01-01

The domestic cat (Felis catus) is an invasive exotic in many locations around the world and is thought to be a key factor driving recent mammal declines across northern Australia. Many mammal species native to this region now persist only in areas with high topographic complexity, provided by features such as gorges or escarpments. Do mammals persist in these habitats because cats occupy them less, or despite high cat occupancy? We show that occupancy of feral cats was lower in mammal-rich habitats of high topographic complexity. These results support the idea that predation pressure by feral cats is a factor contributing to the collapse of mammal communities across northern Australia. Managing impacts of feral cats is a global conservation challenge. Conservation actions such as choosing sites for small mammal reintroductions may be more successful if variation in cat occupancy with landscape features is taken into account. PMID:27655024

[Anatomical rationale for lingual nerve injury prevention during mandibular block].

PubMed

Semkin, V A; Dydikin, S S; Kuzin, A V; Sogacheva, V V

2015-01-01

The topographic and anatomical study of lingual nerve structural features was done. It was revealed that during mandibular anesthesia possible lingual nerve injury can occur if puncture needle is lower than 1 cm. of molars occlusal surface level. The position of the lingual nerve varies withmandible movements. At the maximum open mouth lingual nerve is not mobile and is pressed against the inner surface of the mandibular ramus by the medial pterygoid muscle and the temporal muscle tendon. When closing the mouth to 1.25±0.2 cmfrom the physiological maximum, lingual nerve is displaced posteriorly from the internal oblique line of the mandible and gets mobile. On the basis of topographic and anatomic features of the lingual nervestructure the authors recommend the re-do of inferior alveolar nerve block, a semi-closed mouth position or the use the "high block techniques" (Torus anesthesia, Gow-Gates, Vazirani-Akinozi).

The Landsat Image Mosaic of Antarctica

USGS Publications Warehouse

Bindschadler, Robert; Vornberger, P.; Fleming, A.; Fox, A.; Mullins, J.; Binnie, D.; Paulsen, S.J.; Granneman, Brian J.; Gorodetzky, D.

2008-01-01

The Landsat Image Mosaic of Antarctica (LIMA) is the first true-color, high-spatial-resolution image of the seventh continent. It is constructed from nearly 1100 individually selected Landsat-7 ETM+ scenes. Each image was orthorectified and adjusted for geometric, sensor and illumination variations to a standardized, almost seamless surface reflectance product. Mosaicing to avoid clouds produced a high quality, nearly cloud-free benchmark data set of Antarctica for the International Polar Year from images collected primarily during 1999-2003. Multiple color composites and enhancements were generated to illustrate additional characteristics of the multispectral data including: the true appearance of the surface; discrimination between snow and bare ice; reflectance variations within bright snow; recovered reflectance values in regions of sensor saturation; and subtle topographic variations associated with ice flow. LIMA is viewable and individual scenes or user defined portions of the mosaic are downloadable at http://lima.usgs.gov. Educational materials associated with LIMA are available at http://lima.nasa.gov.

Neuropsychological Features of Dyslexia.

ERIC Educational Resources Information Center

Feifer, Steven G.

This literature review provides support for the idea that subtle anatomical and functional deviations in the brain correlate with specific types of reading disorders. It finds evidence that symmetry or reversed asymmetry in the plana temporale may be associated with difficulty in acquiring sound/symbol relationships. Studies are reported to show…

Developmental Regression in Autism Spectrum Disorders

ERIC Educational Resources Information Center

Rogers, Sally J.

2004-01-01

The occurrence of developmental regression in autism is one of the more puzzling features of this disorder. Although several studies have documented the validity of parental reports of regression using home videos, accumulating data suggest that most children who demonstrate regression also demonstrated previous, subtle, developmental differences.…

Stratified Mucin-Producing Intraepithelial Lesion of the Cervix: Subtle Features Not to Be Missed.

PubMed

Schwock, Joerg; Ko, Hyang Mi; Dubé, Valérie; Rouzbahman, Marjan; Cesari, Matthew; Ghorab, Zeina; Geddie, William R

2016-01-01

Stratified mucin-producing intraepithelial lesion (SMILE) is an uncommon premalignant lesion of the uterine cervix. A detailed examination of preinvasive SMILE cases including a comparison of the cytologic features with usual-type adenocarcinoma in situ (AIS) and human papillomavirus (HPV) genotyping was performed. Excisions and preceding Papanicolaou (Pap) tests were retrieved from the files of 2 tertiary care centers. Histologic review estimated the lesional SMILE proportion. Pap tests were reviewed and assessed for architectural, cellular and background features. Cobas® HPV test was performed. 13 cases were identified. Mean/median patient age was 35/33 years (range 23-51 years). Concurrent high-grade squamous intraepithelial lesion was found in 10/13 (77%) and AIS in 8/13 (62%) cases. In 6 cases, SMILE was dominant (≥50%) and represented in 5/6 corresponding Pap tests. Cytology interpretations differed more often in the SMILE-dominant group (p < 0.05). SMILE and AIS had overlapping features. Feathering and prominent nucleoli were absent in SMILE. HPV DNA was detected in all 12 cases tested. HPV 18 was most common (7/12). Excisions with positive/suspicious margins were reported in 5/6 SMILE-dominant versus 3/7 nondominant cases. SMILE is best considered as an AIS variant for cytologic, etiologic and management purposes. Cytologic features overlap with AIS, but are more subtle and easily missed. HPV testing may play a role in facilitating SMILE detection. © 2016 S. Karger AG, Basel.

Imaging of earthquake faults using small UAVs as a pathfinder for air and space observations

USGS Publications Warehouse

Donnellan, Andrea; Green, Joseph; Ansar, Adnan; Aletky, Joseph; Glasscoe, Margaret; Ben-Zion, Yehuda; Arrowsmith, J. Ramón; DeLong, Stephen B.

2017-01-01

Large earthquakes cause billions of dollars in damage and extensive loss of life and property. Geodetic and topographic imaging provide measurements of transient and long-term crustal deformation needed to monitor fault zones and understand earthquakes. Earthquake-induced strain and rupture characteristics are expressed in topographic features imprinted on the landscapes of fault zones. Small UAVs provide an efficient and flexible means to collect multi-angle imagery to reconstruct fine scale fault zone topography and provide surrogate data to determine requirements for and to simulate future platforms for air- and space-based multi-angle imaging.

MindDigger: Feature Identification and Opinion Association for Chinese Movie Reviews

NASA Astrophysics Data System (ADS)

Zhao, Lili; Li, Chunping

In this paper, we present a prototype system called MindDigger, which can be used to analyze the opinions in Chinese movie reviews. Different from previous research that employed techniques on product reviews, we focus on Chinese movie reviews, in which opinions are expressed in subtle and varied ways. The system designed in this work aims to extract the opinion expressions and assign them to the corresponding features. The core tasks include feature and opinion extraction, and feature-opinion association. To deal with Chinese effectively, several novel approaches based on syntactic analysis are proposed in this paper. Running results show the performance is satisfactory.

Viking 1 Lander on the surface of Mars - Revised location

NASA Technical Reports Server (NTRS)

Morris, E. C.; Jones, K. L.

1980-01-01

The method used to pinpoint the location of the Viking 1 Lander is described. The higher resolution of pictures taken by the Viking Orbiter at a lower periapsis altitude facilitated the correlation of topographical features with the same features in the Lander pictures. The new areographic coordinates of the Lander are 22.483 deg N latitude and 47.968 deg W longitude.

Fake/Bogus Conferences: Their Features and Some Subtle Ways to Differentiate Them from Real Ones.

PubMed

Asadi, Amin; Rahbar, Nader; Rezvani, Mohammad Javad; Asadi, Fahime

2018-04-01

The main objective of the present paper is to introduce some features of fake/bogus conferences and some viable approaches to differentiate them from the real ones. These fake/bogus conferences introduce themselves as international conferences, which are multidisciplinary and indexed in major scientific digital libraries. Furthermore, most of the fake/bogus conference holders offer publishing the accepted papers in ISI journals and use other techniques in their advertisement e-mails.

Shaded relief, color as height, Fiji

NASA Technical Reports Server (NTRS)

2000-01-01

The Sovereign Democratic Republic of the Fiji Islands, commonly known as Fiji, is an independent nation consisting of some 332 islands surrounding the Koro Sea in the South Pacific Ocean. This topographic image shows Viti Levu, the largest island in the group. With an area of 10,429 square kilometers (about 4000 square miles), it comprises more than half the area of the Fiji Islands. Suva, the capital city, lies on the southeast shore. The Nakauvadra, the rugged mountain range running from north to south, has several peaks rising above 900 meters (about 3000 feet). Mount Tomanivi, in the upper center, is the highest peak at 1324 meters (4341 feet). The distinct circular feature on the north shore is the Tavua Caldera, the remnant of a large shield volcano that was active about 4 million years ago. Gold has been mined on the margin of the caldera since the 1930's. The Nadrau plateau is the low relief highland in the center of the mountain range. The coastal plains in the west, northwest and southeast account for only 15 percent of Viti Levu's area but are the main centers of agriculture and settlement.

This shaded relief image was generated using topographic data from the Shuttle Radar Topography Mission. A computer-generated artificial light source illuminates the elevation data to produce a pattern of light and shadows. Slopes facing the light appear bright, while those facing away are shaded. On flatter surfaces, the pattern of light and shadows can reveal subtle features in the terrain. Colors show the elevation as measured by SRTM. Colors range from green at the lowest elevations top ink at the highest elevations. This image contains about 1300 meters(4300 feet) of total relief.

The Shuttle Radar Topography Mission (SRTM), launched on February 11,2000, uses the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. The mission is designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, an additional C-band imaging antenna and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration (NASA), the National Imagery and Mapping Agency (NIMA) and the German (DLR) and Italian (ASI)space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Earth Science Enterprise, Washington, DC.

Size: 192 km (119 miles) x 142 km (88 miles) Location: 17.8 deg. South lat., 178.0 deg. East lon. Orientation: North at top Original Data Resolution: 30 meters (99 feet) Date Acquired: February 19, 2000 Image: NASA/JPL/NIMA

Mesoscale numerical modeling of meteorological events in a strong topographic gradient in the northeastern part of Mexico

NASA Astrophysics Data System (ADS)

Pineda-Martinez, Luis F.; Carbajal, Noel

2009-08-01

A series of numerical experiments were carried out to study the effect of meteorological events such as warm and cold air masses on climatic features and variability of a understudied region with strong topographic gradients in the northeastern part of Mexico. We applied the mesoscale model MM5. We investigated the influence of soil moisture availability in the performance of the model under two representative events for winter and summer. The results showed that a better resolution in land use cover improved the agreement among observed and calculated data. The topography induces atmospheric circulation patterns that determine the spatial distribution of climate and seasonal behavior. The numerical experiments reveal regions favorable to forced convection on the eastern side of the mountain chains Eastern Sierra Madre and Sierra de Alvarez. These processes affect the vertical and horizontal structure of the meteorological variables along the topographic gradient.

Theory connecting nonlocal sediment transport, earth surface roughness, and the Sadler effect

NASA Astrophysics Data System (ADS)

Schumer, Rina; Taloni, Alessandro; Furbish, David Jon

2017-03-01

Earth surface evolution, like many natural phenomena typified by fluctuations on a wide range of scales and deterministic smoothing, results in a statistically rough surface. We present theory demonstrating that scaling exponents of topographic and stratigraphic statistics arise from long-time averaging of noisy surface evolution rather than specific landscape evolution processes. This is demonstrated through use of "elastic" Langevin equations that generically describe disturbance from a flat earth surface using a noise term that is smoothed deterministically via sediment transport. When smoothing due to transport is a local process, the geologic record self organizes such that a specific Sadler effect and topographic power spectral density (PSD) emerge. Variations in PSD slope reflect the presence or absence and character of nonlocality of sediment transport. The range of observed stratigraphic Sadler slopes captures the same smoothing feature combined with the presence of long-range spatial correlation in topographic disturbance.

Feature-based characterisation of signature topography in laser powder bed fusion of metals

NASA Astrophysics Data System (ADS)

Senin, Nicola; Thompson, Adam; Leach, Richard

2018-04-01

The use of state-of-the-art areal topography measurement instrumentation allows for a high level of detail in the acquisition of topographic information at micrometric scales. The 3D geometric models of surface topography obtained from measured data create new opportunities for the investigation of manufacturing processes through characterisation of the surfaces of manufactured parts. Conventional methods for quantitative assessment of topography usually only involve the computation of texture parameters, summary indicators of topography-related characteristics that are computed over the investigated area. However, further useful information may be obtained through characterisation of signature topographic formations, as more direct indicators of manufacturing process behaviour and performance. In this work, laser powder bed fusion of metals is considered. An original algorithmic method is proposed to isolate relevant topographic formations and to quantify their dimensional and geometric properties, using areal topography data acquired by state-of-the-art areal topography measurement instrumentation.

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

Malashkevich, Vladimir N.; Higgins, Chelsea D.; Almo, Steven C.

The coiled-coil is one of the most ubiquitous and well studied protein structural motifs. Significant effort has been devoted to dissecting subtle variations of the typical heptad repeat sequence pattern that can designate larger topological features such as relative α-helical orientation and oligomer size. Here in this paper we report the X-ray structure of a model coiled-coil peptide, HA2-Del-L2seM, which forms an unanticipated core antiparallel dimer with potential sites for discrete higher-order multimerization (trimer or tetramer). In the X-ray structure, a third, partially-ordered α-helix is weakly associated with the antiparallel dimer and analytical ultracentrifugation experiments indicate the peptide forms amore » well-defined tetramer in solution. The HA2-Del-L2seM sequence is closely related to a parent model peptide, HA2-Del, which we previously reported adopts a parallel trimer; HA2-Del-L2seM differs by only hydrophobic leucine to selenomethione mutations and thus this subtle difference is sufficient to switch both relative α-helical topology and number of α-helices participating in the coiled-coil. Comparison of the X-ray structures of HA2-Del-L2seM (reported here) with the HA2-Del parent (reported previously) reveals novel interactions involving the selenomethionine residues that promote antiparallel coiled-coil configuration and preclude parallel trimer formation. Finally, these novel atomic insights are instructive for understanding subtle features that can affect coiled-coil topology and provide additional information for design of antiparallel coiled-coils.« less

Design of converging stepped spillways

USDA-ARS?s Scientific Manuscript database

Roller compacted concrete (RCC) stepped spillways are growing in popularity for providing overtopping protection for aging watershed dams with inadequate auxiliary spillway capacity and for the construction of new dams. Unobtainable land rights, topographic features, and land use changes caused by ...

Whittle Communications and Channel One: Rhetorical Strategies of Innovation.

ERIC Educational Resources Information Center

Adams, Scott

A study examined the message features that influence an innovation's acceptance by a mass audience. The study looked at three strategies of innovational rhetoric (denial of controversy, subtle criticism of existing institutions, and projection of a rhetorical vision) used by a commercial broadcasting company, called Whittle Communications in 1989,…

Managing Students' Learning in Classrooms: Reframing Classroom Research.

ERIC Educational Resources Information Center

Fawns, Rod; Salder, Jo

1996-01-01

Analyzes Australian students' public and private statements to themselves and their peers collected in the course of a multiyear study of teacher management of communication in cooperative learning groups. Data reflect how students perceived and responded to subtle features in the public enactment of the curriculum, the task, and the setting…

Surficial geology of the Safsaf region, south-central Egypt, derived from remote-sensing and field data

USGS Publications Warehouse

Davis, P.A.; Breed, C.S.; McCauley, J.F.; Schaber, G.G.

1993-01-01

We used a decorrelation-stretched image of Landsat Thematic Mapper (TM) Bands 1, 4, and 7 and field data to map and describe the main surficial units in the hyperarid Safsaf region in south-central Egypt. We show that the near-infrared bands on Landsat TM, which are sensitive to very subtle changes in mineralogy common to arid regions, significantly improve the geologist's capability to discriminate geologic units in desert regions. These data also provide the spatial and spectral information necessary to determine the migration patterns and provenance of eolian materials. The Safsaf area was the focus of our post flight field studies using Shuttle Imaging Radar (SIR) data following the discovery of buried paleochannels in North Africa. Most of the channels discernible on SIR images are not expressed in TM data, but traces of a few channels are present in both the SIR and the TM data within the Wadi Safsaf area. Here we present a detailed digital examination of the SIR and the TM-band reflectance and reflectance-ratio data at three locations of the more obvious surface expressions of the buried channels. Our results indicate that the TM expressions of the channels are not purely topographic but are more compositional in nature. Two possibilities may account for the TM expressions of the buried channels: 1) concentrations of windblown, iron-rich materials that accumulated along subtle curvilinear topograpohic traps, or 2) curvilinear exposures of an iron-rich underlying unit of the flat sand sheet. ?? 1993.

Effects of groundwater flow on the distribution of biogenic gas in parts of the northern Great Plains of Canada and United States

USGS Publications Warehouse

Anna, Lawrence O.

2011-01-01

Parts of the northern Great Plains in eastern Montana and western North Dakota and southeastern Alberta and southwestern Saskatchewan, Canada, were studied as part of an assessment of shallow biogenic gas in Upper Cretaceous rocks.Parts of the northern Great Plains in eastern Montana and western North Dakota and southeastern Alberta and southwestern Saskatchewan, Canada, were studied as part of an assessment of shallow biogenic gas in Upper Cretaceous rocks. Large quantities of shallow biogenic gas are produced from low-permeability, Upper Cretaceous reservoirs in southeastern Alberta and southwestern Saskatchewan, Canada. Rocks of similar types and age produce sparingly in the United States except on large structures, such as Bowdoin dome and Cedar Creek anticline. Significant production also occurs in the Tiger Ridge area, where uplift of the Bearpaw Mountains created stratigraphic traps. The resource in Canada is thought to be a continuous, biogenic-gas-type accumulation with economic production in a variety of subtle structures and stratigraphic settings. The United States northern Great Plains area has similar conditions but only broad structural closures or stratigraphic traps associated with local structure have produced economically to date. Numerical flow modeling was used to help determine that biogenic gas in low-permeability reservoirs is held in place by high hydraulic head that overrides buoyancy forces of the gas. Modeling also showed where hydraulic head is greater under Tertiary capped topographic remnants rather than near adjacent topographic lows. The high head can override the capillary pressure of the rock and force gas to migrate to low head in topographically low areas. Most current biogenic gas production is confined to areas between mapped lineaments in the northern Great Plains. The lineaments may reflect structural zones in the Upper Cretaceous that help compartmentalize reservoirs and confine gas accumulations.

Shaded relief of Bahia State, Brazil

NASA Technical Reports Server (NTRS)

2000-01-01

This topographic image is the first to show the full 240-kilometer-wide (150 mile)swath collected by the Shuttle Radar Topography Mission (SRTM). The area shown is in the state of Bahia in Brazil. The semi-circular mountains along the left side of the image are the Serra Da Jacobin, which rise to 1100 meters (3600 feet) above sea level. The total relief shown is approximately 800 meters (2600 feet). The top part of the image is the Sertao, a semi-arid region, that is subject to severe droughts during El Nino events. A small portion of the San Francisco River, the longest river (1609 kilometers or 1000 miles) entirely within Brazil, cuts across the upper right corner of the image. This river is a major source of water for irrigation and hydroelectric power. Mapping such regions will allow scientists to better understand the relationships between flooding cycles, drought and human influences on ecosystems.

This shaded relief image was generated using topographic data from the Shuttle Radar Topography Mission. A computer-generated artificial light source illuminates the elevation data to produce a pattern of light and shadows. Slopes facing the light appear bright, while those facing away are shaded. On flatter surfaces, the pattern of light and shadows can reveal subtle features in the terrain. Colors show the elevation as measured by SRTM. Colors range from green at the lowest elevations to reddish at the highest elevations. Shaded relief maps are commonly used in applications such as geologic mapping and land use planning.

The Shuttle Radar Topography Mission (SRTM), launched on February 11, 2000, uses the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. The mission is designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, an additional C-band imaging antenna and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration (NASA), the National Imagery and Mapping Agency (NIMA) and the German (DLR) and Italian (ASI) space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Earth Science Enterprise, Washington, DC.

Factors in life science textbooks that may deter girls' interest in science

NASA Astrophysics Data System (ADS)

Potter, Ellen F.; Rosser, Sue V.

In order to examine factors that may deter girls' interest in science, five seventh-grade life science textbooks were analyzed for sexism in language, images, and curricular content, and for features of activities that have been found to be useful for motivating girls. Although overt sexism was not apparent, subtle forms of sexism in the selection of language, images, and curricular content were found. Activities had some features useful to girls, but other features were seldom included. Teachers may wish to use differences that were found among texts as one basis for text selection.

Application of GNSS-RTK derived topographical maps for rapid environmental monitoring: a case study of Jack Finnery Lake (Perth, Australia).

PubMed

Schloderer, Glen; Bingham, Matthew; Awange, Joseph L; Fleming, Kevin M

2011-09-01

In environmental monitoring, environmental impact assessments and environmental audits, topographical maps play an essential role in providing a means by which the locations of sampling sites may be selected, in assisting with the interpretation of physical features, and in indicating the impact or potential impact on an area due to changes in the system being monitored (e.g., spatially changing features such as wetlands). Global Navigation Satellite Systems (GNSS) are hereby presented as a rapid method for monitoring spatial changes to support environmental monitoring decisions and policies. To validate the GNSS-based method, a comparison is made of results from a small-scale topographic survey using radio-based real-time kinematic GNSS (GNSS-RTK) and total station survey methods at Jack Finnery Lake, Perth, Australia. The accuracies achieved by the total station in this study were 2 cm horizontally and 6 cm vertically, while the GNSS-RTK also achieved an accuracy of 2 cm horizontally, but only 28 cm vertically. While the GNSS-RTK measurements were less accurate in the height component compared to those from the total station method, it is still capable of achieving accuracies sufficient for a topographic map at a scale of 1:1,750 that could support environmental monitoring tasks such as identifying spatial changes in small water bodies or wetlands. The time taken to perform the survey using GNSS-RTK, however, was much shorter compared to the total station method, thereby making it quite suitable for monitoring spatial changes within an environmental context, e.g., dynamic mining activities that require rapid surveys and the updating of the monitored data at regular intervals.

Multi-scale characterization of topographic anisotropy

NASA Astrophysics Data System (ADS)

Roy, S. G.; Koons, P. O.; Osti, B.; Upton, P.; Tucker, G. E.

2016-05-01

We present the every-direction variogram analysis (EVA) method for quantifying orientation and scale dependence of topographic anisotropy to aid in differentiation of the fluvial and tectonic contributions to surface evolution. Using multi-directional variogram statistics to track the spatial persistence of elevation values across a landscape, we calculate anisotropy as a multiscale, direction-sensitive variance in elevation between two points on a surface. Tectonically derived topographic anisotropy is associated with the three-dimensional kinematic field, which contributes (1) differential surface displacement and (2) crustal weakening along fault structures, both of which amplify processes of surface erosion. Based on our analysis, tectonic displacements dominate the topographic field at the orogenic scale, while a combination of the local displacement and strength fields are well represented at the ridge and valley scale. Drainage network patterns tend to reflect the geometry of underlying active or inactive tectonic structures due to the rapid erosion of faults and differential uplift associated with fault motion. Regions that have uniform environmental conditions and have been largely devoid of tectonic strain, such as passive coastal margins, have predominantly isotropic topography with typically dendritic drainage network patterns. Isolated features, such as stratovolcanoes, are nearly isotropic at their peaks but exhibit a concentric pattern of anisotropy along their flanks. The methods we provide can be used to successfully infer the settings of past or present tectonic regimes, and can be particularly useful in predicting the location and orientation of structural features that would otherwise be impossible to elude interpretation in the field. Though we limit the scope of this paper to elevation, EVA can be used to quantify the anisotropy of any spatially variable property.

FEX: A Knowledge-Based System For Planimetric Feature Extraction

NASA Astrophysics Data System (ADS)

Zelek, John S.

1988-10-01

Topographical planimetric features include natural surfaces (rivers, lakes) and man-made surfaces (roads, railways, bridges). In conventional planimetric feature extraction, a photointerpreter manually interprets and extracts features from imagery on a stereoplotter. Visual planimetric feature extraction is a very labour intensive operation. The advantages of automating feature extraction include: time and labour savings; accuracy improvements; and planimetric data consistency. FEX (Feature EXtraction) combines techniques from image processing, remote sensing and artificial intelligence for automatic feature extraction. The feature extraction process co-ordinates the information and knowledge in a hierarchical data structure. The system simulates the reasoning of a photointerpreter in determining the planimetric features. Present efforts have concentrated on the extraction of road-like features in SPOT imagery. Keywords: Remote Sensing, Artificial Intelligence (AI), SPOT, image understanding, knowledge base, apars.

A multiscale analysis of coral reef topographic complexity using lidar-derived bathymetry

USGS Publications Warehouse

Zawada, D.G.; Brock, J.C.

2009-01-01

Coral reefs represent one of the most irregular substrates in the marine environment. This roughness or topographic complexity is an important structural characteristic of reef habitats that affects a number of ecological and environmental attributes, including species diversity and water circulation. Little is known about the range of topographic complexity exhibited within a reef or between different reef systems. The objective of this study was to quantify topographic complexity for a 5-km x 5-km reefscape along the northern Florida Keys reef tract, over spatial scales ranging from meters to hundreds of meters. The underlying dataset was a 1-m spatial resolution, digital elevation model constructed from lidar measurements. Topographic complexity was quantified using a fractal algorithm, which provided a multi-scale characterization of reef roughness. The computed fractal dimensions (D) are a measure of substrate irregularity and are bounded between values of 2 and 3. Spatial patterns in D were positively correlated with known reef zonation in the area. Landward regions of the study site contain relatively smooth (D ??? 2.35) flat-topped patch reefs, which give way to rougher (D ??? 2.5), deep, knoll-shaped patch reefs. The seaward boundary contains a mixture of substrate features, including discontinuous shelf-edge reefs, and exhibits a corresponding range of roughness values (2.28 ??? D ??? 2.61). ?? 2009 Coastal Education and Research Foundation.

Automatic Imitation

ERIC Educational Resources Information Center

Heyes, Cecilia

2011-01-01

"Automatic imitation" is a type of stimulus-response compatibility effect in which the topographical features of task-irrelevant action stimuli facilitate similar, and interfere with dissimilar, responses. This article reviews behavioral, neurophysiological, and neuroimaging research on automatic imitation, asking in what sense it is "automatic"…

Microorganisms in small patterned ground features and adjacent vegetated soils along topographic and climatic gradients in the High Arctic, Canada

Treesearch

G. Gonzalez; F.J. Rivera-Figueroa; W. Gould; S.A. Cantrell; J.R. Pérez-Jiménez

2014-01-01

In this study, we determine differences in total biomass of soil microorganisms and community structure (using the most probable number of bacteria (MPN) and the number of fungal genera) in patterned ground features (PGF) and adjacent vegetated soils (AVS) in mesic sites from three High Arctic islands in order to characterize microbial dynamics as affected by...

Understanding of the Geomorphological Elements in Discrimination of Typical Mediterranean Land Cover Types

NASA Astrophysics Data System (ADS)

Elhag, Mohamed; Boteva, Silvena

2017-12-01

Quantification of geomorphometric features is the keystone concern of the current study. The quantification was based on the statistical approach in term of multivariate analysis of local topographic features. The implemented algorithm utilizes the Digital Elevation Model (DEM) to categorize and extract the geomorphometric features embedded in the topographic dataset. The morphological settings were exercised on the central pixel of 3x3 per-defined convolution kernel to evaluate the surrounding pixels under the right directional pour point model (D8) of the azimuth viewpoints. Realization of unsupervised classification algorithm in term of Iterative Self-Organizing Data Analysis Technique (ISODATA) was carried out on ASTER GDEM within the boundary of the designated study area to distinguish 10 morphometric classes. The morphometric classes expressed spatial distribution variation in the study area. The adopted methodology is successful to appreciate the spatial distribution of the geomorphometric features under investigation. The conducted results verified the superimposition of the delineated geomorphometric elements over a given remote sensing imagery to be further analyzed. Robust relationship between different Land Cover types and the geomorphological elements was established in the context of the study area. The domination and the relative association of different Land Cover types in corresponding to its geomorphological elements were demonstrated.

Tall Mountain: Enhanced View

NASA Image and Video Library

2015-08-06

Among the highest features seen on Ceres so far is a mountain about 4 miles (6 kilometers) high, which is roughly the elevation of Mount McKinley in Alaska's Denali National Park. This image comes from an animation, shown in PIA19619, generated using data from NASA's Dawn spacecraft. Vertical relief has been exaggerated by a factor of five. Exaggerating the relief helps scientists understand and visualize the topography much more easily, and highlights features that are sometimes subtle. http://photojournal.jpl.nasa.gov/catalog/PIA19618

Looking into the future: An inward bias in aesthetic experience driven only by gaze cues.

PubMed

Chen, Yi-Chia; Colombatto, Clara; Scholl, Brian J

2018-07-01

The inward bias is an especially powerful principle of aesthetic experience: In framed images (e.g. photographs), we prefer peripheral figures that face inward (vs. outward). Why does this bias exist? Since agents tend to act in the direction in which they are facing, one intriguing possibility is that the inward bias reflects a preference to view scenes from a perspective that will allow us to witness those predicted future actions. This account has been difficult to test with previous displays, in which facing direction is often confounded with either global shape profiles or the relative locations of salient features (since e.g. someone's face is generally more visually interesting than the back of their head). But here we demonstrate a robust inward bias in aesthetic judgment driven by a cue that is socially powerful but visually subtle: averted gaze. Subjects adjusted the positions of people in images to maximize the images' aesthetic appeal. People with direct gaze were not placed preferentially in particular regions, but people with averted gaze were reliably placed so that they appeared to be looking inward. This demonstrates that the inward bias can arise from visually subtle features, when those features signal how future events may unfold. Copyright © 2018. Published by Elsevier B.V.

Age, Health and Attractiveness Perception of Virtual (Rendered) Human Hair

PubMed Central

Fink, Bernhard; Hufschmidt, Carla; Hirn, Thomas; Will, Susanne; McKelvey, Graham; Lankhof, John

2016-01-01

The social significance of physical appearance and beauty has been documented in many studies. It is known that even subtle manipulations of facial morphology and skin condition can alter people’s perception of a person’s age, health and attractiveness. While the variation in facial morphology and skin condition cues has been studied quite extensively, comparably little is known on the effect of hair on social perception. This has been partly caused by the technical difficulty of creating appropriate stimuli for investigations of people’s response to systematic variation of certain hair characteristics, such as color and style, while keeping other features constant. Here, we present a modeling approach to the investigation of human hair perception using computer-generated, virtual (rendered) human hair. In three experiments, we manipulated hair diameter (Experiment 1), hair density (Experiment 2), and hair style (Experiment 3) of human (female) head hair and studied perceptions of age, health and attractiveness. Our results show that even subtle changes in these features have an impact on hair perception. We discuss our findings with reference to previous studies on condition-dependent quality cues in women that influence human social perception, thereby suggesting that hair is a salient feature of human physical appearance, which contributes to the perception of beauty. PMID:28066276

Study on Site Conditions Based on Topographic Slope

NASA Astrophysics Data System (ADS)

Wu, X.; Wang, X.; Yuan, X.; Chen, M.; Dou, A.

2018-04-01

The travel-time averaged shear-wave velocity to a depth of 30m (Vs30) below the Earth's surface is widely used to classify sites in many building codes. Vs30 is also used to estimate site classification in recent ground-motion prediction equations (GMPEs), and the distribution of Vs30 has been mapped in a region or country. An alternative method has recently been proposed for evaluating global seismic site conditions or Vs30, from the SRTM (Shuttle Radar Topography Mission) DEMs (digital elevation models). The basic premise of the method is that the topographic slope can be used as a reliable proxy for Vs30 in the absence of geologically and geotechnically based site-condition maps through correlations between Vs30 measurements and topographic gradient. Here, we use different resolutions (3 arcsec, 30 arcsec) DEM data to get Vs30 data separately, analyze and compare the difference of Vs30 data and site conditions obtained from different resolution DEM data. Shandong Province in eastern China and Sichuan Province in Western China are studied respectively. It is found that the higher resolution data is better at defining spatial topographic features than the 30c data, but less improvement in its correlation with Vs30.

A suite of global, cross-scale topographic variables for environmental and biodiversity modeling

NASA Astrophysics Data System (ADS)

Amatulli, Giuseppe; Domisch, Sami; Tuanmu, Mao-Ning; Parmentier, Benoit; Ranipeta, Ajay; Malczyk, Jeremy; Jetz, Walter

2018-03-01

Topographic variation underpins a myriad of patterns and processes in hydrology, climatology, geography and ecology and is key to understanding the variation of life on the planet. A fully standardized and global multivariate product of different terrain features has the potential to support many large-scale research applications, however to date, such datasets are unavailable. Here we used the digital elevation model products of global 250 m GMTED2010 and near-global 90 m SRTM4.1dev to derive a suite of topographic variables: elevation, slope, aspect, eastness, northness, roughness, terrain roughness index, topographic position index, vector ruggedness measure, profile/tangential curvature, first/second order partial derivative, and 10 geomorphological landform classes. We aggregated each variable to 1, 5, 10, 50 and 100 km spatial grains using several aggregation approaches. While a cross-correlation underlines the high similarity of many variables, a more detailed view in four mountain regions reveals local differences, as well as scale variations in the aggregated variables at different spatial grains. All newly-developed variables are available for download at Data Citation 1 and for download and visualization at http://www.earthenv.org/topography.

Neurologic and developmental features of the Smith-Magenis syndrome (del 17p11.2).

PubMed

Gropman, Andrea L; Duncan, Wallace C; Smith, Ann C M

2006-05-01

The Smith-Magenis syndrome is a rare, complex multisystemic disorder featuring, mental retardation and multiple congenital anomalies caused by a heterozygous interstitial deletion of chromosome 17p11.2. The phenotype of Smith-Magenis syndrome is characterized by a distinct pattern of features including infantile hypotonia, generalized complacency and lethargy in infancy, minor skeletal (brachycephaly, brachydactyly) and craniofacial features, ocular abnormalities, middle ear and laryngeal abnormalities including hoarse voice, as well as marked early expressive speech and language delays, psychomotor and growth retardation, and a 24-hour sleep disturbance. A striking neurobehavioral pattern of stereotypies, hyperactivity, polyembolokoilamania, onychotillomania, maladaptive and self-injurious and aggressive behavior is observed with increasing age. The diagnosis of Smith-Magenis syndrome is based upon the clinical recognition of a constellation of physical, developmental, and behavioral features in combination with a sleep disorder characterized by inverted circadian rhythm of melatonin secretion. Many of the features of Smith-Magenis syndrome are subtle in infancy and early childhood, and become more recognizable with advancing age. Infants are described as looking "cherubic" with a Down syndrome-like appearance, whereas with age the facial appearance is that of relative prognathism. Early diagnosis requires awareness of the often subtle clinical and neurobehavioral phenotype of the infant period. Speech delay with or without hearing loss is common. Most children are diagnosed in mid-childhood when the features of the disorder are most recognizable and striking. While improvements in cytogenetic analysis help to bring cases to clinical recognition at an earlier age, this review seeks to increase clinical awareness about Smith-Magenis syndrome by presenting the salient features observed at different ages including descriptions of the neurologic and behavioral features. Detailed review of the circadian rhythm disturbance unique to Smith-Magenis syndrome is presented. Suggestions for management of the behavioral and sleep difficulties are discussed in the context of the authors' personal experience in the setting of an ongoing Smith-Magenis syndrome natural history study.

Terraced margins of inflated lava flows on Earth and Mars

NASA Astrophysics Data System (ADS)

Zimbelman, J. R.; Garry, W. B.; Bleacher, J. E.; Crumpler, L. S.

2011-12-01

When fluid basaltic lava flows are emplaced over a shallow regional slope (typically much less than one degree), the lava flows often display impressive characteristics of inflation. Here we describe a distinctive marginal characteristic that is often developed along the margins of endogenously inflated basaltic lava flows; discreet topographic levels of the emplaced lava that are here termed 'terraced margins'. Terraced margins were first noted at the distal end of the Carrizozo lava flow in central New Mexico, where they are particularly well expressed, but terraces have also been observed along some margins of the McCartys lava flow (NM), the distal end of the 1859 Mauna Loa lava flow (HI), and lava flows at Craters of the Moon (ID). Differential Global Positioning System surveys across several terraced margins reveal consistent topographic characteristics: the upper surface of each terrace level is at roughly one half the height of the sheet lobe from which it emerges; when a terrace becomes the source of an additional outbreak, the upper surface of the second terrace is at roughly one half the height of the source terrace; often a subtle topographic depression is present along the contact between a terrace and its source sheet lobe, suggesting that the terrace outflow starts at a level roughly one-third the height of the source lobe; the upper surfaces of both the source sheet lobe and associated terraces are level to within tens of centimeters across length scales of many tens to hundreds of meters, indicative of inflation of all components. The field observations will be used as the constraints for modeling of the inflation and terracing mechanisms, an effort that has only recently started. The multiple imaging data sets now available for Mars have revealed the presence of terraced margins on some lava flows on Mars. Although detailed topographic data are not currently available for the Martian examples identified so far, the presence of terraced margins for lava flows on both Earth and Mars indicates that the terracing mechanism is intimately associated with the lava flow inflation process. This work was supported by grants from the Planetary Geology and Geophysics program of NASA (NNX09AD88G) and the Scholarly Studies program of the Smithsonian Institution.

The distribution of organic material and its contribution to the micro-topography of particles from wettable and water repellent soils

NASA Astrophysics Data System (ADS)

Bryant, Rob; Cheng, Shuying; Doerr, Stefan H.; Wright, Chris J.; Bayer, Julia V.; Williams, Rhodri P.

2010-05-01

Organic coatings on mineral particles will mask the physic-chemical properties of the underlying mineral surface. Surface images and force measurements obtained using atomic force microscopy (AFM) provide information about the nature of and variability in surfaces properties at the micro- to nano-scale. As AFM technology and data processing advance it is anticipated that a significant amount of information will be obtained simultaneously from individual contacts made at high frequency in non-contact or tapping mode operation. For present purposes the surfaces of model materials (smooth glass surfaces and acid-washed sand (AWS)) provide an indication of the dependency of the so-called AFM phase image on the topographic image (which is obtained synoptically). Pixel wise correlation of these images reveals how the modulation of an AFM probe is affected when topographic features are encountered. Adsorption of soil-derived humic acid (HA) or lecithin (LE), used here as an example for natural organic material, on these surfaces provides a soft and compliant, albeit partial, covering on the mineral which modifies the topography and the response of an AFM tip as it partially indents the soft regions (which contributes depth to the phase image). This produces a broadening on the data domain in the topographic/phase scatter diagram. Two dimensional classifications of these data, together with those obtained from sand particles drawn from water repellent and wettable soils, suggest that these large adsorbate molecules appear to have little preference to attach to particular topographic features or elevations. It appears that they may effectively remain on the surface at the point of initial contact. If organic adsorbates present a hydrophobic outer surface, then it seems possible that elevated features will not be immune from this and provide scope for a local, albeit, small contribution to the expression of super-hydrophobicity. It is therefore speculated here that the water repellency of a soil is the result of not only of particle surface chemistry and soil pore space geometry, but also of the micro-topography generated by organic material adsorbed on particle surfaces.

Artist's concept of topographical layout of Taurus-Littrow landing site

NASA Image and Video Library

1972-10-01

S72-49761 (October 1972) --- An artist's concept illustrating the topographical layout of the Taurus-Littrow landing site of the Apollo 17 lunar landing mission. The Lunar Module touchdown point is in the center of the smooth area in the middle of the picture. The imposing mountain in the center is South Massif. A portion of North Massif is in the lower right corner of the photograph. Note the ridge-like feature extending from South Massif to North Massif. The southern portion of the ridge is called Lee Scarp and the northerly portion Lincoln Scarp. (This concept is by JSC artist Jerry Elmore).

Identifying the educative and suppressive effects of positive practice and restitutional overcorrection.

PubMed Central

Carey, R G; Bucher, B

1981-01-01

Two major features of the overcorrection procedure, restitution and positive practice, were analyzed for their educative and suppressive properties in the treatment of profoundly retarded adults. Positive practice techniques that were topographically similar and dissimilar to the target behavior were studied. Eating behavior and puzzle performance were observed. Restitutional overcorrection and both forms of positive practice were effective for suppressing inappropriate behaviors. Even when appropriate behaviors had been acquired by positive practice, restitution and dissimilar positive practice were generally ineffective for increasing their rate of occurrence. However, topographically similar positive practice was successful as a means of teaching new appropriate behaviors. PMID:7216933

Identifying the educative and suppressive effects of positive practice and restitutional overcorrection.

PubMed

Carey, R G; Bucher, B

1981-01-01

Two major features of the overcorrection procedure, restitution and positive practice, were analyzed for their educative and suppressive properties in the treatment of profoundly retarded adults. Positive practice techniques that were topographically similar and dissimilar to the target behavior were studied. Eating behavior and puzzle performance were observed. Restitutional overcorrection and both forms of positive practice were effective for suppressing inappropriate behaviors. Even when appropriate behaviors had been acquired by positive practice, restitution and dissimilar positive practice were generally ineffective for increasing their rate of occurrence. However, topographically similar positive practice was successful as a means of teaching new appropriate behaviors.

Guidance of dorsal root ganglion neurites and Schwann cells by isolated Schwann cell topography on poly(dimethyl siloxane) conduits and films

NASA Astrophysics Data System (ADS)

Richardson, J. A.; Rementer, C. W.; Bruder, Jan M.; Hoffman-Kim, D.

2011-08-01

Biomimetic replicas of cellular topography have been utilized to direct neurite outgrowth. Here, we cultured postnatal rat dorsal root ganglion (DRG) explants in the presence of Schwann cell (SC) topography to determine the influence of SC topography on neurite outgrowth. Four distinct poly(dimethyl siloxane) conduits were fabricated within which DRG explants were cultured. To determine the contribution of SC topographical features to neurite guidance, the extent of neurite outgrowth into unpatterned conduits, conduits with randomly oriented SC replicas, and conduits with SC replicas parallel or perpendicular to the conduit long axis was measured. Neurite directionality and outgrowth from DRG were also quantified on two-dimensional SC replicas with orientations corresponding to the four conduit conditions. Additionally, live SC migration and neurite extension from DRG on SC replicas were examined as a first step toward quantification of the interactions between live SC and navigating neurites on SC replicas. DRG neurite outgrowth and morphology within conduits and on two-dimensional SC replicas were directed by the underlying SC topographical features. Maximal neurite outgrowth and alignment to the underlying features were observed into parallel conduits and on parallel two-dimensional substrates, whereas the least extent of outgrowth was observed into perpendicular conduits and on perpendicular two-dimensional replica conditions. Additionally, neurites on perpendicular conditions turned to extend along the direction of underlying SC topography. Neurite outgrowth exceeded SC migration in the direction of the underlying anisotropic SC replica after two days in culture. This finding confirms the critical role that SC have in guiding neurite outgrowth and suggests that the mechanism of neurite alignment to SC replicas depends on direct contact with cellular topography. These results suggest that SC topographical replicas may be used to direct and optimize neurite alignment, and emphasize the importance of SC features in neurite guidance.

Optical Coherence Tomography in Glaucoma

NASA Astrophysics Data System (ADS)

Berisha, Fatmire; Hoffmann, Esther M.; Pfeiffer, Norbert

Retinal nerve fiber layer (RNFL) thinning and optic nerve head cupping are key diagnostic features of glaucomatous optic neuropathy. The higher resolution of the recently introduced SD-OCT offers enhanced visualization and improved segmentation of the retinal layers, providing a higher accuracy in identification of subtle changes of the optic disc and RNFL thinning associated with glaucoma.

Prosody Predicts Contest Outcome in Non-Verbal Dialogs

PubMed Central

Dreiss, Amélie N.; Chatelain, Philippe G.

2016-01-01

Non-verbal communication has important implications for inter-individual relationships and negotiation success. However, to what extent humans can spontaneously use rhythm and prosody as a sole communication tool is largely unknown. We analysed human ability to resolve a conflict without verbal dialogs, independently of semantics. We invited pairs of subjects to communicate non-verbally using whistle sounds. Along with the production of more whistles, participants unwittingly used a subtle prosodic feature to compete over a resource (ice-cream scoops). Winners can be identified by their propensity to accentuate the first whistles blown when replying to their partner, compared to the following whistles. Naive listeners correctly identified this prosodic feature as a key determinant of which whistler won the interaction. These results suggest that in the absence of other communication channels, individuals spontaneously use a subtle variation of sound accentuation (prosody), instead of merely producing exuberant sounds, to impose themselves in a conflict of interest. We discuss the biological and cultural bases of this ability and their link with verbal communication. Our results highlight the human ability to use non-verbal communication in a negotiation process. PMID:27907039

Prosody Predicts Contest Outcome in Non-Verbal Dialogs.

PubMed

Dreiss, Amélie N; Chatelain, Philippe G; Roulin, Alexandre; Richner, Heinz

2016-01-01

Non-verbal communication has important implications for inter-individual relationships and negotiation success. However, to what extent humans can spontaneously use rhythm and prosody as a sole communication tool is largely unknown. We analysed human ability to resolve a conflict without verbal dialogs, independently of semantics. We invited pairs of subjects to communicate non-verbally using whistle sounds. Along with the production of more whistles, participants unwittingly used a subtle prosodic feature to compete over a resource (ice-cream scoops). Winners can be identified by their propensity to accentuate the first whistles blown when replying to their partner, compared to the following whistles. Naive listeners correctly identified this prosodic feature as a key determinant of which whistler won the interaction. These results suggest that in the absence of other communication channels, individuals spontaneously use a subtle variation of sound accentuation (prosody), instead of merely producing exuberant sounds, to impose themselves in a conflict of interest. We discuss the biological and cultural bases of this ability and their link with verbal communication. Our results highlight the human ability to use non-verbal communication in a negotiation process.

HISTORICAL COASTAL WETLANDS OF PRUDENCE ISLAND

EPA Science Inventory

Historical maps are useful tools to assess long-term change. The topographic surveys (T-charts) produced by the U.S. Coast and Geodedetic Survey, predecessor of the U.S.Geologic Survey (USGS), provide a rich source of information on historical environmental features dating back t...

Maps showing aeromagnetic data and interpretation for the Kalmiopsis Wilderness, southwestern Oregon

USGS Publications Warehouse

Blakely, Richard J.; Page, Norman J; Gray, Floyd; Senior, Lisa; Ryan, Holly F.

1983-01-01

Most individual anomalies in this area are caused by known geologic boundaries or topographic features; those that are not are of particular interest because they may reflect areas of increased or decreased magnetization associated with zones of minerlization. 

Global Ocean Vertical Velocity From a Dynamically Consistent Ocean State Estimate

NASA Astrophysics Data System (ADS)

Liang, Xinfeng; Spall, Michael; Wunsch, Carl

2017-10-01

Estimates of the global ocean vertical velocities (Eulerian, eddy-induced, and residual) from a dynamically consistent and data-constrained ocean state estimate are presented and analyzed. Conventional patterns of vertical velocity, Ekman pumping, appear in the upper ocean, with topographic dominance at depth. Intense and vertically coherent upwelling and downwelling occur in the Southern Ocean, which are likely due to the interaction of the Antarctic Circumpolar Current and large-scale topographic features and are generally canceled out in the conventional zonally averaged results. These "elevators" at high latitudes connect the upper to the deep and abyssal oceans and working together with isopycnal mixing are likely a mechanism, in addition to the formation of deep and abyssal waters, for fast responses of the deep and abyssal oceans to the changing climate. Also, Eulerian and parameterized eddy-induced components are of opposite signs in numerous regions around the global ocean, particularly in the ocean interior away from surface and bottom. Nevertheless, residual vertical velocity is primarily determined by the Eulerian component, and related to winds and large-scale topographic features. The current estimates of vertical velocities can serve as a useful reference for investigating the vertical exchange of ocean properties and tracers, and its complex spatial structure ultimately permits regional tests of basic oceanographic concepts such as Sverdrup balance and coastal upwelling/downwelling.

Substrate Topography Induces a Crossover from 2D to 3D Behavior in Fibroblast Migration

PubMed Central

Ghibaudo, Marion; Trichet, Léa; Le Digabel, Jimmy; Richert, Alain; Hersen, Pascal; Ladoux, Benoît

2009-01-01

Abstract In a three-dimensional environment, cells migrate through complex topographical features. Using microstructured substrates, we investigate the role of substrate topography in cell adhesion and migration. To do so, fibroblasts are plated on chemically identical substrates composed of microfabricated pillars. When the dimensions of the pillars (i.e., the diameter, length, and spacing) are varied, migrating cells encounter alternating flat and rough surfaces that depend on the spacing between the pillars. Consequently, we show that substrate topography affects cell shape and migration by modifying cell-to-substrate interactions. Cells on micropillar substrates exhibit more elongated and branched shapes with fewer actin stress fibers compared with cells on flat surfaces. By analyzing the migration paths in various environments, we observe different mechanisms of cell migration, including a persistent type of migration, that depend on the organization of the topographical features. These responses can be attributed to a spatial reorganization of the actin cytoskeleton due to physical constraints and a preferential formation of focal adhesions on the micropillars, with an increased lifetime compared to that observed on flat surfaces. By changing myosin II activity, we show that actomyosin contractility is essential in the cellular response to micron-scale topographic signals. Finally, the analysis of cell movements at the frontier between flat and micropillar substrates shows that cell transmigration through the micropillar substrates depends on the spacing between the pillars. PMID:19580774

In situ nanoscale observations of gypsum dissolution by digital holographic microscopy.

PubMed

Feng, Pan; Brand, Alexander S; Chen, Lei; Bullard, Jeffrey W

2017-06-01

Recent topography measurements of gypsum dissolution have not reported the absolute dissolution rates, but instead focus on the rates of formation and growth of etch pits. In this study, the in situ absolute retreat rates of gypsum (010) cleavage surfaces at etch pits, at cleavage steps, and at apparently defect-free portions of the surface are measured in flowing water by reflection digital holographic microscopy. Observations made on randomly sampled fields of view on seven different cleavage surfaces reveal a range of local dissolution rates, the local rate being determined by the topographical features at which material is removed. Four characteristic types of topographical activity are observed: 1) smooth regions, free of etch pits or other noticeable defects, where dissolution rates are relatively low; 2) shallow, wide etch pits bounded by faceted walls which grow gradually at rates somewhat greater than in smooth regions; 3) narrow, deep etch pits which form and grow throughout the observation period at rates that exceed those at the shallow etch pits; and 4) relatively few, submicrometer cleavage steps which move in a wave-like manner and yield local dissolution fluxes that are about five times greater than at etch pits. Molar dissolution rates at all topographical features except submicrometer steps can be aggregated into a continuous, mildly bimodal distribution with a mean of 3.0 µmolm -2 s -1 and a standard deviation of 0.7 µmolm -2 s -1 .

Martian Buried Basins and Implications for Characteristics of the Burial Layer and Underlying Surface

NASA Technical Reports Server (NTRS)

Sarid, A. R.; Frey, H. V.; Roark, J. H.

2003-01-01

Deciphering the cratering record on Mars has been challenging because it may reflect the changes in both the population of impactors and in the resurfacing processes on Mars. However, it is possible to determine the breadth of impactors captured in the cratering record. Extensive areas of resurfacing are of particular interest because they likely contain material from various ages in Martian history. By deducing the impact populations in both surface and underlying layers of terrain, it is possible to determine the age of the layers and constrain theories on the development of the Martian surface. However, to do so requires a method of seeing impact features which are no longer visible. Topographic data of Mars, taken by the Mars Orbiter Laser Altimeter (MOLA), has revealed impact features buried by resurfacing processes. These features are often indistinguishable on Viking images of the Martian surface. In this study, gridded MOLA data was analyzed in order to locate buried impact features, also called buried basins, in Syria, Solis, and Sinai Planum just south of Valles Marineris. The population statistics of buried features can be compared to those of visible features in order to determine the age of the underlying material and characteristics of the surface cover. Specifically, if the buried population in the Hesperian terrain is similar to the population of visible features in the Noachian, it would suggest that the underlying terrain is Noachian in age. The buried craters can then be compared to visible Noachian craters to reveal the amount of deterioration of the buried features. These comparisons allow us to explore the morphology of the terrain in the Hesperian region to determine if topographic variations are due to differences in the thickness of the overlying material or are a characteristic of the underlying terrain.

Regional Topographic Properties of Pluto and Charon from New Horizons

NASA Astrophysics Data System (ADS)

Schenk, P.; Beyer, R. A.; Moore, J. M.; Spencer, J. R.; McKinnon, W. B.; Weaver, H. A., Jr.; Young, L. A.; Olkin, C.; Ennico Smith, K.; Stern, A.

2016-12-01

Topographic mapping was among the high priority observations for both Pluto and Charon, and as a result these are the best characterized icy bodies outside of Ceres and the Saturn system in terms of topography. Roughly 30-40% of each body was mapped in stereo, resulting in high-quality DEM mapping coverage of both at vertical resolutions of 100-500 m and spatial scales of 300-800 m. On Charon, stereo mapping reveals the rolling topography of Vulcan Planum and its marginal "moat" depressed several hundred meters. The older cratered plains are also broken into large blocks 100-300 km across, separated by extensional troughs 1-3 km deep. Total relief across Charon exceeds 15 km, making it one of the most rugged midsize icy bodies outside Iapetus. Pluto is divided into several distinct geologic provinces, each with its own topographic character. The globally highest features are the elevated bladed terrain plateaus standing 2-3 km high. Cratered plains to the northwest have low relief of a few hundred meters, except for 2-3 km deep unmodified extensional fractures. Etched or eroded plains to the east have local relief of 2-3 km. The most dominant feature is the 3-km deep elliptical basin associated with the nitrogen-rich ice plains of Sputnik Planitia (informally named). This depression most obviously resembles large impact basins on other bodies, most notably Hellas basin on Mars and Caloris basin on Mercury. The basin has a raised rim in some quadrants but is very ancient and eroded and primary impact textures are now lost. Nonetheless, a low-velocity oblique impact remains the most likely explanation for this feature, leaving a depression that became the focus for subsequent volatile ice accumulation.

The Plains of Venus

NASA Astrophysics Data System (ADS)

Sharpton, V. L.

2013-12-01

Volcanic plains units of various types comprise at least 80% of the surface of Venus. Though devoid of topographic splendor and, therefore often overlooked, these plains units house a spectacular array of volcanic, tectonic, and impact features. Here I propose that the plains hold the keys to understanding the resurfacing history of Venus and resolving the global stratigraphy debate. The quasi-random distribution of impact craters and the small number that have been conspicuously modified from the outside by plains-forming volcanism have led some to propose that Venus was catastrophically resurfaced around 725×375 Ma with little volcanism since. Challenges, however, hinge on interpretations of certain morphological characteristics of impact craters: For instance, Venusian impact craters exhibit either radar dark (smooth) floor deposits or bright, blocky floors. Bright floor craters (BFC) are typically 100-400 m deeper than dark floor craters (DFC). Furthermore, all 58 impact craters with ephemeral bright ejecta rays and/or distal parabolic ejecta patterns have bright floor deposits. This suggests that BFCs are younger, on average, than DFCs. These observations suggest that DFCs could be partially filled with lava during plains emplacement and, therefore, are not strictly younger than the plains units as widely held. Because the DFC group comprises ~80% of the total crater population on Venus the recalculated emplacement age of the plains would be ~145 Ma if DFCs are indeed volcanically modified during plains formation. Improved image and topographic data are required to measure stratigraphic and morphometric relationships and resolve this issue. Plains units are also home to an abundant and diverse set of volcanic features including steep-sided domes, shield fields, isolated volcanoes, collapse features and lava channels, some of which extend for 1000s of kilometers. The inferred viscosity range of plains-forming lavas, therefore, is immense, ranging from the extremely fluid flows (i.e., channel formers), to viscous, possibly felsic lavas of steep-sided domes. Wrinkle ridges deform many plains units and this has been taken to indicate that these ridges essentially form an early stratigraphic marker that limits subsequent volcanism to a minimum. However, subtle backscatter variations within many ridged plains units suggest (but do not prove) that some plains volcanism continued well after local ridge deformation ended. Furthermore, many of volcanic sources show little, if any, indications of tectonic modification and detailed analyses have concluded that resurfacing rates could be similar to those on Earth. Improving constraints on the rates and styles of volcanism within the plains could lend valuable insights into the evolution of Venus's internal heat budget and the transition from thin-lid to thick-lid tectonic regimes. Improved spatial and radiometric resolution of radar images would greatly improve abilities to construct the complex local stratigraphy of ridged plains. Constraining the resurfacing history of Venus is central to understanding how Earth-sized planets evolve and whether or not their evolutionary pathways lead to habitability. This goal can only be adequately addressed if broad coverage is added to the implementation strategies of any future mapping missions to Venus.

A Regional Guidebook for Applying the Hydrogeomorphic Approach to Assessing Functions of Forested Wetlands in the Mississippi Alluvial Valley

DTIC Science & Technology

2013-07-01

Definition Depression Depressional wetlands occur in topographic depressions (i.e., closed elevation contours) that allow the accumulation of surface water... depression . The predominant hydrodynamics are vertical fluctuations that may occur over a range of time, from a few days to many months. Depressional ... depression in dunefields ............................... 3b. Depressional feature in abandoned meander features (oxbows or swales) not subject to 5-year

On the Perception of Religious Group Membership from Faces

PubMed Central

Rule, Nicholas O.; Garrett, James V.; Ambady, Nalini

2010-01-01

Background The study of social categorization has largely been confined to examining groups distinguished by perceptually obvious cues. Yet many ecologically important group distinctions are less clear, permitting insights into the general processes involved in person perception. Although religious group membership is thought to be perceptually ambiguous, folk beliefs suggest that Mormons and non-Mormons can be categorized from their appearance. We tested whether Mormons could be distinguished from non-Mormons and investigated the basis for this effect to gain insight to how subtle perceptual cues can support complex social categorizations. Methodology/Principal Findings Participants categorized Mormons' and non-Mormons' faces or facial features according to their group membership. Individuals could distinguish between the two groups significantly better than chance guessing from their full faces and faces without hair, with eyes and mouth covered, without outer face shape, and inverted 180°; but not from isolated features (i.e., eyes, nose, or mouth). Perceivers' estimations of their accuracy did not match their actual accuracy. Exploration of the remaining features showed that Mormons and non-Mormons significantly differed in perceived health and that these perceptions were related to perceptions of skin quality, as demonstrated in a structural equation model representing the contributions of skin color and skin texture. Other judgments related to health (facial attractiveness, facial symmetry, and structural aspects related to body weight) did not differ between the two groups. Perceptions of health were also responsible for differences in perceived spirituality, explaining folk hypotheses that Mormons are distinct because they appear more spiritual than non-Mormons. Conclusions/Significance Subtle markers of group membership can influence how others are perceived and categorized. Perceptions of health from non-obvious and minimal cues distinguished individuals according to their religious group membership. These data illustrate how the non-conscious detection of very subtle differences in others' appearances supports cognitively complex judgments such as social categorization. PMID:21151864

Digitally enhanced GLORIA images for petroleum exploration

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

Prindle, R.O.; Lanz, K

1990-05-01

This poster presentation graphically depicts the geological and structural information that can be derived from digitally enhanced Geological Long Range Inclined Asdic (GLORIA) sonar images. This presentation illustrates the advantages of scale enlargement as an interpreter's tool in an offshore area within the Eel River Basin, Northern California. Sonographs were produced from digital tapes originally collected for the exclusive economic zone (EEZ)-SCAN 1984 survey, which was published in the Atlas of the Western Conterminous US at a scale of 1:500,000. This scale is suitable for displaying regional offshore tectonic features but does not have the resolution required for detailed geologicalmore » mapping necessary for petroleum exploration. Applications of digital enhancing techniques which utilize contrast stretching and assign false colors to wide-swath sonar imagery (approximately 40 km) with 50-m resolution enables the acquisition and interpretation of significantly more geological and structural data. This, combined with a scale enlargement to 1:100,000 and high contrast contact prints vs. the offset prints of the atlas, increases the resolution and sharpness of bathymetric features so that many more subtle features may be mapped in detail. A tectonic interpretation of these digitally enhanced GLORIA sonographs from the Eel River basin is presented, displaying anticlines, lineaments, ridge axis, pathways of sediment flow, and subtle doming. Many of these features are not present on published bathymetric maps and have not been derived from seismic data because the plan view spatial resolution is much less than that available from the GLORIA imagery.« less

Study of the Plutino Object (208996) 2003 AZ84 from Stellar Occultations: Size, Shape, and Topographic Features

NASA Astrophysics Data System (ADS)

Dias-Oliveira, A.; Sicardy, B.; Ortiz, J. L.; Braga-Ribas, F.; Leiva, R.; Vieira-Martins, R.; Benedetti-Rossi, G.; Camargo, J. I. B.; Assafin, M.; Gomes-Júnior, A. R.; Baug, T.; Chandrasekhar, T.; Desmars, J.; Duffard, R.; Santos-Sanz, P.; Ergang, Z.; Ganesh, S.; Ikari, Y.; Irawati, P.; Jain, J.; Liying, Z.; Richichi, A.; Shengbang, Q.; Behrend, R.; Benkhaldoun, Z.; Brosch, N.; Daassou, A.; Frappa, E.; Gal-Yam, A.; Garcia-Lozano, R.; Gillon, M.; Jehin, E.; Kaspi, S.; Klotz, A.; Lecacheux, J.; Mahasena, P.; Manfroid, J.; Manulis, I.; Maury, A.; Mohan, V.; Morales, N.; Ofek, E.; Rinner, C.; Sharma, A.; Sposetti, S.; Tanga, P.; Thirouin, A.; Vachier, F.; Widemann, T.; Asai, A.; Hayato, Watanabe; Hiroyuki, Watanabe; Owada, M.; Yamamura, H.; Hayamizu, T.; Bradshaw, J.; Kerr, S.; Tomioka, H.; Andersson, S.; Dangl, G.; Haymes, T.; Naves, R.; Wortmann, G.

2017-07-01

We present results derived from four stellar occultations by the plutino object (208996) 2003 AZ84, detected on 2011 January 8 (single-chord event), 2012 February 3 (multi-chord), 2013 December 2 (single-chord), and 2014 November 15 (multi-chord). Our observations rule out an oblate spheroid solution for 2003 AZ84's shape. Instead, assuming hydrostatic equilibrium, we find that a Jacobi triaxial solution with semiaxes (470+/- 20)× (383+/- 10)× (245+/- 8) km can better account for all our occultation observations. Combining these dimensions with the rotation period of the body (6.75 hr) and the amplitude of its rotation light curve, we derive a density ρ =0.87+/- 0.01 g cm-3, a geometric albedo {p}V=0.097+/- 0.009. A grazing chord observed during the 2014 occultation reveals a topographic feature along 2003 AZ84's limb, which can be interpreted as an abrupt chasm of width ˜23 km and depth > 8 km, or a smooth depression of width ˜80 km and depth ˜13 km (or an intermediate feature between those two extremes).

Delineating wetland catchments and modeling hydrologic ...

EPA Pesticide Factsheets

In traditional watershed delineation and topographic modeling, surface depressions are generally treated as spurious features and simply removed from a digital elevation model (DEM) to enforce flow continuity of water across the topographic surface to the watershed outlets. In reality, however, many depressions in the DEM are actual wetland landscape features with seasonal to permanent inundation patterning characterized by nested hierarchical structures and dynamic filling–spilling–merging surface-water hydrological processes. Differentiating and appropriately processing such ecohydrologically meaningful features remains a major technical terrain-processing challenge, particularly as high-resolution spatial data are increasingly used to support modeling and geographic analysis needs. The objectives of this study were to delineate hierarchical wetland catchments and model their hydrologic connectivity using high-resolution lidar data and aerial imagery. The graph-theory-based contour tree method was used to delineate the hierarchical wetland catchments and characterize their geometric and topological properties. Potential hydrologic connectivity between wetlands and streams were simulated using the least-cost-path algorithm. The resulting flow network delineated potential flow paths connecting wetland depressions to each other or to the river network on scales finer than those available through the National Hydrography Dataset. The results demonstrated that

Automatic Classification of High Resolution Satellite Imagery - a Case Study for Urban Areas in the Kingdom of Saudi Arabia

NASA Astrophysics Data System (ADS)

Maas, A.; Alrajhi, M.; Alobeid, A.; Heipke, C.

2017-05-01

Updating topographic geospatial databases is often performed based on current remotely sensed images. To automatically extract the object information (labels) from the images, supervised classifiers are being employed. Decisions to be taken in this process concern the definition of the classes which should be recognised, the features to describe each class and the training data necessary in the learning part of classification. With a view to large scale topographic databases for fast developing urban areas in the Kingdom of Saudi Arabia we conducted a case study, which investigated the following two questions: (a) which set of features is best suitable for the classification?; (b) what is the added value of height information, e.g. derived from stereo imagery? Using stereoscopic GeoEye and Ikonos satellite data we investigate these two questions based on our research on label tolerant classification using logistic regression and partly incorrect training data. We show that in between five and ten features can be recommended to obtain a stable solution, that height information consistently yields an improved overall classification accuracy of about 5%, and that label noise can be successfully modelled and thus only marginally influences the classification results.

Valley Network Morphology and Topographic Gradients on Mars

NASA Technical Reports Server (NTRS)

Aharonson, Oded; Zuber, Maria T.; Rothman, Daniel H.; Schorghofer, Norbert; Phillips, Roger J.; Williams, Rebecca M. E.

2001-01-01

Data returned from the Mars Orbiter Laser Altimeter allows construction of a high precision digital elevation model. Quantitative investigations into the geomorphic properties of drainage features, similar to ones carried out on Earth, are now possible Additional information is contained in the original extended abstract.

Inference of physical/biological dynamics from synthetic ocean colour images

NASA Technical Reports Server (NTRS)

Eert, J.; Holloway, G.; Gower, J. F. R.; Denman, K.; Abbott, M.

1987-01-01

High resolution numerical experiments with well resolved eddies are performed including advection of a biologically active plankton field. Shelf wave propagation and bottom topographic features are included. The resulting synthetic ocean color fields are examined for sensitivity to the (known) underlying physical dynamics.

Global correlation of topographic heights and gravity anomalies

NASA Technical Reports Server (NTRS)

Roufosse, M. C.

1977-01-01

The short wavelength features were obtained by subtracting a calculated 24th-degree-and-order field from observed data written in 1 deg x 1 deg squares. The correlation between the two residual fields was examined by a program of linear regression. When run on a worldwide scale over oceans and continents separately, the program did not exhibit any correlation; this can be explained by the fact that the worldwide autocorrelation function for residual gravity anomalies falls off much faster as a function of distance than does that for residual topographic heights. The situation was different when the program was used in restricted areas, of the order of 5 deg x 5 deg square. For 30% of the world,fair-to-good correlations were observed, mostly over continents. The slopes of the regression lines are proportional to apparent densities, which offer a large spectrum of values that are being interpreted in terms of features in the upper mantle consistent with available heat-flow, gravity, and seismic data.

Map Separates

USGS Publications Warehouse

,

2001-01-01

U.S. Geological Survey (USGS) topographic maps are printed using up to six colors (black, blue, green, red, brown, and purple). To prepare your own maps or artwork based on maps, you can order separate black-and-white film positives or negatives for any color printed on a USGS topographic map, or for one or more of the groups of related features printed in the same color on the map (such as drainage and drainage names from the blue plate.) In this document, examples are shown with appropriate ink color to illustrate the various separates. When purchased, separates are black-and-white film negatives or positives. After you receive a film separate or composite from the USGS, you can crop, enlarge or reduce, and edit to add or remove details to suit your special needs. For example, you can adapt the separates for making regional and local planning maps or for doing many kinds of studies or promotions by using the features you select and then printing them in colors of your choice.

Mapping hydrological environments in central Amazonia: ground validation and surface model based on SRTM DEM data corrected for deforestation

NASA Astrophysics Data System (ADS)

Moulatlet, G. M.; Rennó, C. D.; Costa, F. R. C.; Emilio, T.; Schietti, J.

2015-03-01

One of the most important freely available digital elevation models (DEMs) for Amazonia is the one obtained by the Shuttle Radar Topography Mission (SRTM). However, since SRTM tends to represent the vegetation surface instead of the ground surface, the broad use of SRTM DEM as a framework for terrain description in Amazonia is hampered by the presence of deforested areas. We present here two data sets: (1) a deforestation-corrected SRTM DEM for the interfluve between the Purus and Madeira rivers, in central Amazonia, which passed through a careful identification of different environments and has deforestation features corrected by a new method of increasing pixel values of the DEM (Rennó, 2009); and (2) a set of 18 hydrological-topographic descriptors based on the corrected SRTM DEM. Deforestation features are related with the opening of an 800 km road in the central part of the interfluve and occupancy of its vicinity. We used topographic profiles from the pristine forest to the deforested feature to evaluate the recovery of the original canopy coverage by minimizing canopy height variation (corrections ranged from 1 to 38 m). The hydrological-topographic description was obtained by the Height Above the Nearest Drainage (HAND) algorithm, which normalizes the terrain elevation (above sea level) by the elevation of the nearest hydrologically connected drainage. The validation of the HAND data set was done by in situ hydrological description of 110 km of walking trails also available in this data set. The new SRTM DEM expands the applicability of SRTM data for landscape modelling; the data sets of hydrological features based on topographic modelling are undoubtedly appropriate for ecological modelling and an important contribution to environmental mapping of Amazonia. The deforestation-corrected SRTM DEM is available at http://ppbio.inpa.gov.br/knb/metacat/naman.318.3/ppbio; the polygons selected for deforestation correction are available at http://ppbio.inpa.gov.br/knb/metacat/naman.317.3/ppbio; the set of hydrological-topographic descriptors is available at http://ppbio.inpa.gov.br/knb/metacat/naman.544.2/ppbio; the environmental description of access trails is available at http://ppbio.inpa.gov.br/knb/metacat/naman.541.2/ppbio; and the limits of deforestation corrections and drainage validation are available at http://ppbio.inpa.gov.br/knb/metacat/liliandias.38.1/ppbio.

Evaluating topographic effects on ground deformation: Insights from finite element modeling

NASA Astrophysics Data System (ADS)

Ronchin, Erika; Geyer, Adelina; Marti, Joan

2015-04-01

Ground deformation has been demonstrated to be one of the most common signals of volcanic unrest. Although volcanoes are commonly associated with significant topographic relief, most analytical models assumed the Earth's surface as flat. In the last years, it has been confirmed that this approximation can lead to important misinterpretations of the recorded surface deformation data. Here we perform a systematic and quantitative analysis of how topography may influence ground deformation signals and how these variations correlate with the different topographic parameters characterizing the terrain form (e.g. slope, aspect, curvature, etc.). For this, we bring together the results exposed in previous published papers and complement them with new axisymmetric and 3D Finite Elements (FE) models results. First, we study, in a parametric way, the influence of a volcanic edifice centered above the pressure source axis. Second, we carry out new 3D FE models simulating the real topography of three different volcanic areas representative of topographic scenarios common in volcanic regions: Rabaul caldera (Papua New Guinea) and the volcanic islands of Tenerife and El Hierro (Canary Islands). The calculated differences are then correlated with a series of topographic parameters. The final aim is to investigate the artifacts that might arise from the use of half-space models at volcanic areas considering their diverse topographic features (e.g. collapse caldera structures, prominent central edifices, large landslide scars, etc.). Final conclusions may be also useful for the design of an optimal geodetic monitoring network. This research was partially funded by the European Commission (FP7 Theme: ENV.2011.1.3.3-1; Grant 282759: "VUELCO")and RYC-2012-11024.

A theoretical study of topographic effects on coastal upwelling and cross-shore exchange

NASA Astrophysics Data System (ADS)

Song, Y. Tony; Chao, Yi

The effects of topographic variations on coastal upwelling and cross-shore exchange are examined with a theoretical, continuously stratified, three-dimensional coastal ocean model. The model takes into account topographic variations in both alongshore and cross-shore directions and allows analytical solutions with an Ekman surface layer that faithfully represents the physical nature of the coastal upwelling system. Theoretical solutions with any analytical form of alongshore-varying topography can be solved based on the perturbation method of Killworth [J. Phys. Oceanogr. 8 (1978) 188]. Analyses of the model solutions lead to the following conclusions: The variation of upwelling fronts and currents is shown to be caused by the combined effect of topography and stratification. Topographic variation causes uneven upwelling distribution and leads to density variation, which results in a varying horizontal pressure gradient field that causes the meandering currents. The variation index is dependent upon a bilinear function of their physical parameters--the ratio of the topographic variation depth to the total depth and Burger's number of stratification. Cross-shore slope is found to play a role in maintaining the meandering structure of the alongshore currents. The anticyclonic circulations can further induce downwelling on the offshore side of the current, while the cyclonic circulations enhance upwelling and form upwelling centers on the inshore side of the current. Alongshore topography does not change the total upwelled water, i.e., the total Ekman pumping is conserved. However, it increases cross-exchange of water masses by transporting inshore (offshore) water near topographic features far offshore (inshore) from the mean position of the front. The applicability and limitations of the theory are also discussed.

Topographic and Bioclimatic Determinants of the Occurrence of Forest and Grassland in Tropical Montane Forest-Grassland Mosaics of the Western Ghats, India

PubMed Central

Das, Arundhati; Nagendra, Harini; Anand, Madhur; Bunyan, Milind

2015-01-01

The objective of this analysis was to identify topographic and bioclimatic factors that predict occurrence of forest and grassland patches within tropical montane forest-grassland mosaics. We further investigated whether interactions between topography and bioclimate are important in determining vegetation pattern, and assessed the role of spatial scale in determining the relative importance of specific topographic features. Finally, we assessed the role of elevation in determining the relative importance of diverse explanatory factors. The study area consists of the central and southern regions of the Western Ghats of Southern India, a global biodiversity hotspot. Random forests were used to assess prediction accuracy and predictor importance. Conditional inference classification trees were used to interpret predictor effects and examine potential interactions between predictors. GLMs were used to confirm predictor importance and assess the strength of interaction terms. Overall, topographic and bioclimatic predictors classified vegetation pattern with approximately 70% accuracy. Prediction accuracy was higher for grassland than forest, and for mosaics at higher elevations. Elevation was the most important predictor, with mosaics above 2000m dominated largely by grassland. Relative topographic position measured at a local scale (within a 300m neighbourhood) was another important predictor of vegetation pattern. In high elevation mosaics, northness and concave land surface curvature were important predictors of forest occurrence. Important bioclimatic predictors were: dry quarter precipitation, annual temperature range and the interaction between the two. The results indicate complex interactions between topography and bioclimate and among topographic variables. Elevation and topography have a strong influence on vegetation pattern in these mosaics. There were marked regional differences in the roles of various topographic and bioclimatic predictors across the range of study mosaics, indicating that the same pattern of grass and forest seems to be generated by different sets of mechanisms across the region, depending on spatial scale and elevation. PMID:26121353

Topographic and Bioclimatic Determinants of the Occurrence of Forest and Grassland in Tropical Montane Forest-Grassland Mosaics of the Western Ghats, India.

PubMed

Das, Arundhati; Nagendra, Harini; Anand, Madhur; Bunyan, Milind

2015-01-01

The objective of this analysis was to identify topographic and bioclimatic factors that predict occurrence of forest and grassland patches within tropical montane forest-grassland mosaics. We further investigated whether interactions between topography and bioclimate are important in determining vegetation pattern, and assessed the role of spatial scale in determining the relative importance of specific topographic features. Finally, we assessed the role of elevation in determining the relative importance of diverse explanatory factors. The study area consists of the central and southern regions of the Western Ghats of Southern India, a global biodiversity hotspot. Random forests were used to assess prediction accuracy and predictor importance. Conditional inference classification trees were used to interpret predictor effects and examine potential interactions between predictors. GLMs were used to confirm predictor importance and assess the strength of interaction terms. Overall, topographic and bioclimatic predictors classified vegetation pattern with approximately 70% accuracy. Prediction accuracy was higher for grassland than forest, and for mosaics at higher elevations. Elevation was the most important predictor, with mosaics above 2000 m dominated largely by grassland. Relative topographic position measured at a local scale (within a 300 m neighbourhood) was another important predictor of vegetation pattern. In high elevation mosaics, northness and concave land surface curvature were important predictors of forest occurrence. Important bioclimatic predictors were: dry quarter precipitation, annual temperature range and the interaction between the two. The results indicate complex interactions between topography and bioclimate and among topographic variables. Elevation and topography have a strong influence on vegetation pattern in these mosaics. There were marked regional differences in the roles of various topographic and bioclimatic predictors across the range of study mosaics, indicating that the same pattern of grass and forest seems to be generated by different sets of mechanisms across the region, depending on spatial scale and elevation.

Topographic models for predicting malaria vector breeding habitats: potential tools for vector control managers.

PubMed

Nmor, Jephtha C; Sunahara, Toshihiko; Goto, Kensuke; Futami, Kyoko; Sonye, George; Akweywa, Peter; Dida, Gabriel; Minakawa, Noboru

2013-01-16

Identification of malaria vector breeding sites can enhance control activities. Although associations between malaria vector breeding sites and topography are well recognized, practical models that predict breeding sites from topographic information are lacking. We used topographic variables derived from remotely sensed Digital Elevation Models (DEMs) to model the breeding sites of malaria vectors. We further compared the predictive strength of two different DEMs and evaluated the predictability of various habitat types inhabited by Anopheles larvae. Using GIS techniques, topographic variables were extracted from two DEMs: 1) Shuttle Radar Topography Mission 3 (SRTM3, 90-m resolution) and 2) the Advanced Spaceborne Thermal Emission Reflection Radiometer Global DEM (ASTER, 30-m resolution). We used data on breeding sites from an extensive field survey conducted on an island in western Kenya in 2006. Topographic variables were extracted for 826 breeding sites and for 4520 negative points that were randomly assigned. Logistic regression modelling was applied to characterize topographic features of the malaria vector breeding sites and predict their locations. Model accuracy was evaluated using the area under the receiver operating characteristics curve (AUC). All topographic variables derived from both DEMs were significantly correlated with breeding habitats except for the aspect of SRTM. The magnitude and direction of correlation for each variable were similar in the two DEMs. Multivariate models for SRTM and ASTER showed similar levels of fit indicated by Akaike information criterion (3959.3 and 3972.7, respectively), though the former was slightly better than the latter. The accuracy of prediction indicated by AUC was also similar in SRTM (0.758) and ASTER (0.755) in the training site. In the testing site, both SRTM and ASTER models showed higher AUC in the testing sites than in the training site (0.829 and 0.799, respectively). The predictability of habitat types varied. Drains, foot-prints, puddles and swamp habitat types were most predictable. Both SRTM and ASTER models had similar predictive potentials, which were sufficiently accurate to predict vector habitats. The free availability of these DEMs suggests that topographic predictive models could be widely used by vector control managers in Africa to complement malaria control strategies.

Long-term morphological evolution of a morphologically active man-made stream in the Netherlands

NASA Astrophysics Data System (ADS)

Eekhout, J.; Hoitink, T.

2010-12-01

Around 1770, a straight artificial canal (Gelderns-Nierskanaal) has been constructed between the River Niers and the River Meuse, crossing the border between Germany and the Netherlands, with the purpose of reducing flood risk in the downstream reaches of the River Niers. Whereas the German part of the canal is kept straight throughout time, the Dutch part was left unprotected and developed into a morphodynamically active stream featuring a meandering planform. The current planform and in-channel morphology are analyzed using airborne LiDAR data and historical topographic maps. Around the turn of the 18th century, the first attempts were made to make detailed topographic maps. From this time on, at least 16 topographic maps of the area around the stream were made. With the use of these historical topographic maps, a reconstruction is made of the planimetric shape of the stream over a period of 240 years. The LiDAR data show old meander belts at several places around the stream. Those belts compare well with the topographic maps. The sinuosity increases from upstream to downstream. This could be a consequence of the valley slope, where the upper part is flat and the slope increases in downstream direction. Besides, the LiDAR data show that erosion resulted in an incised valley, with dimensions to 50 m in width and 6 m in depth. Both the datasets are combined to make an estimate of the historical sediment budget of the stream.

Mars topographic clouds: MAVEN/IUVS observations and LMD MGCM predictions

NASA Astrophysics Data System (ADS)

Schneider, Nicholas M.; Connour, Kyle; Forget, Francois; Deighan, Justin; Jain, Sonal; Vals, Margaux; Wolff, Michael J.; Chaffin, Michael S.; Crismani, Matteo; Stewart, A. Ian F.; McClintock, William E.; Holsclaw, Greg; Lefevre, Franck; Montmessin, Franck; Stiepen, Arnaud; Stevens, Michael H.; Evans, J. Scott; Yelle, Roger; Lo, Daniel; Clarke, John T.; Jakosky, Bruce

2017-10-01

The Imaging Ultraviolet Spectrograph (IUVS) instrument on the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft takes mid-UV spectral images of the Martian atmosphere. From these apoapse disk images, information about clouds and aerosols can be retrieved and comprise the only MAVEN observations of topographic clouds and cloud morphologies. Measuring local time variability of large-scale recurring cloud features is made possible with MAVEN’s ~4.5-hour elliptical orbit, something not possible with sun-synchronous orbits. We have run the LMD MGCM (Mars global circulation model) at 1° x 1° resolution to simulate water ice cloud formation with inputs consistent with observing parameters and Mars seasons. Topographic clouds are observed to form daily during the late mornings of northern hemisphere spring and this phenomenon recurs until late summer (Ls = 160°), after which topographic clouds wane in thickness. By northern fall, most topographic clouds cease to form except over Arsia Mons and Pavonis Mons, where clouds can still be observed. Our data show moderate cloud formation over these regions as late as Ls = 220°, something difficult for the model to replicate. Previous studies have shown that models have trouble simulating equatorial cloud thickness in combination with a realistic amount of water vapor and not-too-thick polar water ice clouds, implying aspects of the water cycle are not fully understood. We present data/model comparisons as well as further refinements on parameter inputs based on IUVS observations.

Mars topographic clouds: MAVEN/IUVS observations and LMD MGCM predictions

NASA Astrophysics Data System (ADS)

Connour, K.; Schneider, N.; Forget, F.; Deighan, J.; Jain, S.; Pottier, A.; Wolff, M. J.; Chaffin, M.; Crismani, M. M. J.; Stewart, I. F.; McClintock, B.; Holsclaw, G.; Lefèvre, F.; Montmessin, F.; Stiepen, A.; Stevens, M. H.; Evans, J. S.; Yelle, R. V.; Lo, D.; Clarke, J. T.; Jakosky, B. M.

2017-12-01

The Imaging Ultraviolet Spectrograph (IUVS) instrument on the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft takes mid-UV spectral images of the Martian atmosphere. From these apoapse disk images, information about clouds and aerosols can be retrieved and comprise the only MAVEN observations of topographic clouds and cloud morphologies. Measuring local time variability of large-scale recurring cloud features is made possible with MAVEN's 4.5-hour elliptical orbit, something not possible with sun-synchronous orbits. We have run the LMD MGCM (Mars global circulation model) at 1° x 1° resolution to simulate water ice cloud formation with inputs consistent with observing parameters and Mars seasons. Topographic clouds are observed to form daily during the late mornings of northern hemisphere spring and this phenomenon recurs until late summer (Ls = 160°), after which topographic clouds wane in thickness. By northern fall, most topographic clouds cease to form except over Arsia Mons and Pavonis Mons, where clouds can still be observed. Our data show moderate cloud formation over these regions as late as Ls = 220°, something difficult for the model to replicate. Previous studies have shown that models have trouble simulating equatorial cloud thickness in combination with a realistic amount of water vapor and not-too-thick polar water ice clouds, implying aspects of the water cycle are not fully understood. We present data/model comparisons as well as further refinements on parameter inputs based on IUVS observations.

Coma morphology of comet 67P controlled by insolation over irregular nucleus

NASA Astrophysics Data System (ADS)

Shi, X.; Hu, X.; Mottola, S.; Sierks, H.; Keller, H. U.; Rose, M.; Güttler, C.; Fulle, M.; Fornasier, S.; Agarwal, J.; Pajola, M.; Tubiana, C.; Bodewits, D.; Barbieri, C.; Lamy, P. L.; Rodrigo, R.; Koschny, D.; Barucci, M. A.; Bertaux, J.-L.; Bertini, I.; Boudreault, S.; Cremonese, G.; Da Deppo, V.; Davidsson, B.; Debei, S.; De Cecco, M.; Deller, J.; Groussin, O.; Gutiérrez, P. J.; Hviid, S. F.; Ip, W.-H.; Jorda, L.; Knollenberg, J.; Kovacs, G.; Kramm, J.-R.; Kührt, E.; Küppers, M.; Lara, L. M.; Lazzarin, M.; Lopez-Moreno, J. J.; Marzari, F.; Naletto, G.; Oklay, N.; Toth, I.; Vincent, J.-B.

2018-05-01

While the structural complexity of cometary comae is already recognizable from telescopic observations1, the innermost region, within a few radii of the nucleus, was not resolved until spacecraft exploration became a reality2,3. The dust coma displays jet-like features of enhanced brightness superposed on a diffuse background1,4,5. Some features can be traced to specific areas on the nucleus, and result conceivably from locally enhanced outgassing and/or dust emission6-8. However, diffuse or even uniform activity over topographic concavity can converge to produce jet-like features9,10. Therefore, linking observed coma morphology to the distribution of activity on the nucleus is difficult11,12. Here, we study the emergence of dust activity at sunrise on comet 67P/Churyumov-Gerasimenko using high-resolution, stereo images from the OSIRIS camera onboard the Rosetta spacecraft, where the sources and formation of the jet-like features are resolved. We perform numerical simulations to show that the ambient dust coma is driven by pervasive but non-uniform water outgassing from the homogeneous surface layer. Physical collimations of gas and dust flows occur at local maxima of insolation and also via topographic focusing. Coma structures are projected to exhibit jet-like features that vary with the perspective of the observer. For an irregular comet such as 67P/Churyumov-Gerasimenko, near-nucleus coma structures can be concealed in the shadow of the nucleus, which further complicates the picture.

Advancing representation of hydrologic processes in the Soil and Water Assessment Tool (SWAT) through integration of the TOPographic MODEL (TOPMODEL) features

USGS Publications Warehouse

Chen, J.; Wu, Y.

2012-01-01

This paper presents a study of the integration of the Soil and Water Assessment Tool (SWAT) model and the TOPographic MODEL (TOPMODEL) features for enhancing the physical representation of hydrologic processes. In SWAT, four hydrologic processes, which are surface runoff, baseflow, groundwater re-evaporation and deep aquifer percolation, are modeled by using a group of empirical equations. The empirical equations usually constrain the simulation capability of relevant processes. To replace these equations and to model the influences of topography and water table variation on streamflow generation, the TOPMODEL features are integrated into SWAT, and a new model, the so-called SWAT-TOP, is developed. In the new model, the process of deep aquifer percolation is removed, the concept of groundwater re-evaporation is refined, and the processes of surface runoff and baseflow are remodeled. Consequently, three parameters in SWAT are discarded, and two new parameters to reflect the TOPMODEL features are introduced. SWAT-TOP and SWAT are applied to the East River basin in South China, and the results reveal that, compared with SWAT, the new model can provide a more reasonable simulation of the hydrologic processes of surface runoff, groundwater re-evaporation, and baseflow. This study evidences that an established hydrologic model can be further improved by integrating the features of another model, which is a possible way to enhance our understanding of the workings of catchments.

Topographic mapping data semantics through data conversion and enhancement: Chapter 7

USGS Publications Warehouse

Varanka, Dalia; Carter, Jonathan; Usery, E. Lynn; Shoberg, Thomas; Edited by Ashish, Naveen; Sheth, Amit P.

2011-01-01

This paper presents research on the semantics of topographic data for triples and ontologies to blend the capabilities of the Semantic Web and The National Map of the U.S. Geological Survey. Automated conversion of relational topographic data of several geographic sample areas to the triple data model standard resulted in relatively poor semantic associations. Further research employed vocabularies of feature type and spatial relation terms. A user interface was designed to model the capture of non-standard terms relevant to public users and to map those terms to existing data models of The National Map through the use of ontology. Server access for the study area triple stores was made publicly available, illustrating how the development of linked data may transform institutional policies to open government data resources to the public. This paper presents these data conversion and research techniques that were tested as open linked data concepts leveraged through a user-centered interface and open USGS server access to the public.

Observations and laboratory simulations of tornadoes in complex topographical regions

NASA Astrophysics Data System (ADS)

Karstens, Christopher Daniel

Aerial photos taken along the damage paths of the Joplin, MO, and Tuscaloosa-Birmingham, AL, tornadoes of 2011 captured and preserved several unique patterns of damage. In particular, a few distinct tree-fall patterns were noted along the Tuscaloosa-Birmingham tornado track that appeared highly influenced by the underlying topography. One such region was the focus of a damage survey and motivated laboratory vortex simulations with a 3-D foam representation of the underlying topography, in addition to simulations performed with idealized 2D topographic features, using Iowa State University's tornado simulator. The purpose of this dissertation is to explore various aspects related to the interaction of a tornado or a tornado-like vortex with its underlying topography. Three topics are examined: 1) Analysis of tornado-induced tree-fall using aerial photography from the Joplin, MO, and Tuscaloosa-Birmingham, AL, tornadoes of 2011, 2) Laboratory investigation of topographical influences on a simulated tornado-like vortex, and 3) On the use of non-standard EF-scale damage indicators to categorize tornadoes.

Elevations and distances in the United States

USGS Publications Warehouse

,

1991-01-01

The information in this booklet was compiled to answer inquiries received by the U.S. Geological Survey from students; teachers; writers; editors; publishers of encyclopedias, almanacs, and other reference books; and people in many other fields of work. The elevations of features and distances between points in the United States were determined from surveys and topographic maps of the U.S. Geological Survey or obtained from other sources. In most cases, the elevations were determined from surveys and from 1:24,000- and 1:25,000-scale, 7.5-minute topographic quadrangle maps. In Alaska, information was taken from 1:63,360-scale, 15-minute topographic quadrangle maps. In a few cases, data were obtained from older, 1:62,500-scale, 15-minute maps; these maps are being replaced with larger-scale 7.5-minute coverage. Further information about U.S. Geological Survey products can be obtained from: U.S. Geological Survey, Earth Science Information Center, 507 National Center, Reston, VA 22092 or phone 703-860-6045.

Mars - Crustal structure inferred from Bouguer gravity anomalies.

NASA Technical Reports Server (NTRS)

Phillips, R. J.; Saunders, R. S.; Conel, J. E.

1973-01-01

Bouguer gravity has been computed for the equatorial region of Mars by differencing free air gravity and the gravity predicted from topographic variations. The free air gravity was generated from an eighth-order set of spherical harmonic coefficients. The gravity from topographic variations was generated by integrating a two-dimensional Green's function over each contour level. The Bouguer gravity indicates crustal inhomogeneities on Mars that are postulated to be variations in crustal thickness. The Tharsis ridge is a region of thick continental type crust. The gravity data, structural patterns, topography, and surface geology of this region lead to the interpretation of the Tharsis topographic high as a broad crustal upwarp possibly associated with local formation of lower-density crustal material and subsequent rise of a thicker crust. The Amazonis region is one of several basins of relatively thin crust, analogous to terrestrial ocean basins. The Libya and Hellas basins, which are probable impact features, are also underlain by thin crust and are possible regions of mantle upwelling.

The influence of topography on Titan’s atmospheric circulation and hydrologic cycle

NASA Astrophysics Data System (ADS)

Lora, Juan M.; Faulk, Sean; Mitchell, Jonathan

2017-10-01

Titan’s atmospheric circulation is a dominant driver of the global methane hydrologic cycle—producing weather and a seasonal climate cycle—while interactions between the surface and the troposphere strongly constrain regional climates, and contribute to the differentiation between Titan’s low latitude deserts and high latitude lake districts. Yet the influence of surface topography on the atmospheric circulation has only been studied in a few instances, and no published work has investigated the coupling between topographical forcing and Titan’s hydrologic cycle. In this work, we examine the impacts of global topography in the Titan Atmospheric Model (TAM), which includes a robust representation of the methane cycle. We focus in particular on the influence of large-scale topographical features on the atmospheric flow, atmospheric moisture transport, and cloud formation. High latitude transient weather systems have previously been identified as important contributors to global atmospheric methane transport, and here we examine whether topographically-forced stationary or quasi-permanent systems are also important, as they are in Earth’s hydrologic cycle.

SPOT satellite mapping of Ice Stream B

NASA Technical Reports Server (NTRS)

Merry, Carolyn J.

1993-01-01

Numerous features of glaciological significance appear on two adjoining SPOT High Resolution Visible (HRV) images that cover the onset region of ice stream B. Many small-scale features, such as crevasses and drift plumes, have been previously observed in aerial photography. Subtle features, such as long flow traces that have not been mapped previously, are also clear in the satellite imagery. Newly discovered features include ladder-like runners and rungs within certain shear margins, flow traces that are parallel to ice flow, unusual crevasse patterns, and flow traces originating within shear margins. An objective of our work is to contribute to an understanding of the genesis of the features observed in satellite imagery. The genetic possibilities for flow traces, other lineations, bands of transverse crevasses, shear margins, mottles, and lumps and warps are described.

Congenital dysplasias and dwarfism.

PubMed

Clark, R N

1990-11-01

This paper has presented the characteristic features of those types of dwarfism that are manifest at birth. This information has been presented in a fashion that should assist the pediatrician in arriving at an appropriate diagnosis without excessive delay or extensive diagnostic studies. However, variable expressivity may result in subtle presentation and, in those cases, diagnosis may be more challenging.

Black Hole Interior in Quantum Gravity.

PubMed

Nomura, Yasunori; Sanches, Fabio; Weinberg, Sean J

2015-05-22

We discuss the interior of a black hole in quantum gravity, in which black holes form and evaporate unitarily. The interior spacetime appears in the sense of complementarity because of special features revealed by the microscopic degrees of freedom when viewed from a semiclassical standpoint. The relation between quantum mechanics and the equivalence principle is subtle, but they are still consistent.

Advancing Glaciological Applications of Remote Sensing with EO-1: (1) Mapping Snow Grain Size and Albedo on the Greenland Ice Sheet Using an Imaging Spectrometer, and (2) ALI Evaluation for Subtle Surface Topographic Mapping via Shape-from Shading

NASA Technical Reports Server (NTRS)

2003-01-01

The Hyperion sensor, onboard NASA's Earth Observing-1 (EO-1) satellite,is an imaging spectroradiometer with 220 spectral bands over the spectral range from 0.4 - 2.5 microns. Over the course of summer 2001, the instrument acquired numerous images over the Greenland ice sheet. Our main motivation is to develop an accurate and robust approach for measuring the broadband albedo of snow from satellites. Satellite-derived estimates of broadband have typically been plagued with three problems: errors resulting from inaccurate atmospheric correction, particularly in the visible wavelengths from the conversion of reflectance to albedo (accounting for snow BRDE); and errors resulting from regression-based approaches used to convert narrowband albedo to broadband albedo. A typerspectral method has been developed that substantially reduces these three main sources of error and produces highly accurate estimates of snow albedo. This technique uses hyperspectral data from 0.98 - 1.06 microns, spanning a spectral absorption feature centered at 1.03 microns. A key aspect of this work is that this spectral range is within an atmospheric transmission window and reflectances are largely unaffected by atmospheric aerosols, water vapor, or ozone. In this investigation, we make broadband albedo measurements at four sites on the Greenland ice sheet: Summit, a high altitude station in central Greenland; the ETH/CU camp, a camp on the equilibrium line in western Greenland; Crawford Point, a site located between Summit and the ETH/CU camp; and Tunu, a site located in northeastern Greenland at 2000 m. altitude. Each of these sites has an automated weather station (AWS) that continually measures broadband albedo thereby providing validation data.

Spirit's 'Paige' Panorama of the Interior of 'Home Plate' (False Color)

NASA Technical Reports Server (NTRS)

2006-01-01

On Feb. 19, 2006, the 758th Martian day of exploration of the red planet by NASA's Mars Exploration Rover Spirit, the rover acquired this panoramic view of the interior of 'Home Plate,' a circular topographic feature amid the 'Columbia Hills.' This view, called the 'Paige' panorama, is from the top of Home Plate. It shows layered rocks exposed at the edge as well as dark rocks exhibiting both smooth and sponge-like 'scoriaceous' textures. To the east from this vantage point, 'McCool Hill' looms on the horizon. At the base of McCool Hill is a reddish outcrop called 'Oberth,' which Spirit may explore during the rapidly approaching Martian winter. 'Von Braun' and 'Goddard' hills are partially visible beyond the opposite rim of Home Plate.

The limited spatial coverage of this panorama is the result of steadily decreasing power available to the rover for science activities as the Martian winter arrives and the sun traces a lower path across the sky. The rover team anticipates that the north-facing slopes of McCool Hill should sufficiently tilt the rover's solar panels toward the sun to allow Spirit to survive the winter.

The view covers about 230 degrees of terrain around the rover. Spirit's panoramic camera (Pancam) took 72 separate images of this scene with four different Pancam filters. This is a false-color rendering using the Pancam's 75-nanometer, 535-nanometer, and 432-nanometer filters, enhanced to show many subtle color differences in rocks, soils, and hills in the scene. Image-to-image seams have been eliminated from the sky portion of the mosaic to better simulate the vista a person standing on Mars would see.

Thematic mapper-derived mineral distribution maps of Idaho, Nevada, and western Montana

USGS Publications Warehouse

Raines, Gary L.

2006-01-01

This report provides mineral distribution maps based on TM spectral information of minerals commonly associated with hydrothermal alteration in Nevada, Idaho, and western Montana. The product of the processing is provided as four ESRI GRID files with 30 m resolution by state. UTM Zone 11 projection is used for Nevada (grid clsnv) and western Idaho (grid clsid), UTM Zone 12 is used for eastern Idaho and western Montana (grid clsid_mt). A fourth grid with a special Albers projection is used for the Headwaters project covering Idaho and western Montana (grid crccls_hs). Symbolization for all four grids is stored in the ESRI layer or LYR files and color or CLR files. Objectives of the analyses were to cover a large area very quickly and to provide data that could be used at a scale of 1:100,000 or smaller. Thus, the image processing was standardized for speed while still achieving the desired 1:100,000-scale level of detail. Consequently, some subtle features of mineralogy may be missed. The hydrothermal alteration data were not field checked to separate mineral occurrences due to hydrothermal alteration from those due to other natural occurrences. The data were evaluated by overlaying the results with 1:100,000 scale topographic maps to confirm correlation with known mineralized areas. The data were also tested in the Battle Mountain area of north-central Nevada by a weights-of-evidence correlation analysis with metallic mineral sites from the USGS Mineral Resources Data System and were found to have significant spatial correlation. On the basis of on these analyses, the data are considered useful for regional studies at scales of 1:100,000.

Application of multispectral photography to mineral and land resources of South Carolina

NASA Technical Reports Server (NTRS)

Olson, N. K. (Principal Investigator)

1975-01-01

The author has identified the following significant results. Good results were obtained from using Skylab photography in conjunction with LANDSAT imagery for visual interpretation of various geologic features, particularly lineaments. It was concluded that visual interpretation alone of Skylab photographs was quite limited, and much of this was because of the low contrast, heavily vegetated terrain in southeastern United States. Lineaments of major structural features are detectable but subtle. An intimate knowledge of the geologic field relationships is needed before a meaningful analysis is feasible using current satellite photography alone.

Modeling Wetland Vegetation using Polarimetric SAR

NASA Technical Reports Server (NTRS)

Slatton, K. Clint; Crawford, Melba M.; Gibeaut, James C.; Gutierrez, Roberto O.

1996-01-01

A three-year project to study small-scale topographic changes and relict geomorphic features on barrier islands using synthetic aperture radar (SAR) is described. A study area on the Texas coast consisting of Galveston Island and Bolivar Peninsula was overflown by the NASA/JPL DC 8 AIRSAR in April 1995. Data was acquired in the fully polarimetric mode using C-, L-, and P-bands and in the TOPSAR configuration with C- and L-bands in interferometric mode. The study area will be overflown again in late spring 1996. The data will be registered to global positioning system (GPS) surveyed points to form high resolution digital elevation models (DEM) and then analyzed to investigate possible topographic changes.

The Global Positioning System

USGS Publications Warehouse

,

1999-01-01

The Global Positioning System (GPS) is a constellation of navigation satellites called Navigation Satellite Timing And Ranging (NAVSTAR), maintained by the U.S. Department of Defense. Many outdoor enthusiasts recognize that a handheld GPS receiver can be an accurate tool for determining their location on the terrain. The GPS receiver helps determine locations on the Earth's surface by collecting signals from three or more satellites through a process called triangulation. Identifying a location on the Earth is more useful if you also know about the surrounding topographic conditions. Using a topographic map with the GPS receiver provides important information about features of the surrounding terrain and can help you plot an effective route from one location to another.

Engineering design of sub-micron topographies for simultaneously adherent and reflective metal-polymer interfaces

NASA Technical Reports Server (NTRS)

Brown, Christopher A.

1993-01-01

The approach of the project is to base the design of multi-function, reflective topographies on the theory that topographically dependent phenomena react with surfaces and interfaces at certain scales. The first phase of the project emphasizes the development of methods for understanding the sizes of topographic features which influence reflectivity. Subsequent phases, if necessary, will address the scales of interaction for adhesion and manufacturing processes. A simulation of the interaction of electromagnetic radiation, or light, with a reflective surface is performed using specialized software. Reflectivity of the surface as a function of scale is evaluated and the results from the simulation are compared with reflectivity measurements made on multi-function, reflective surfaces.

Geologic information from satellite images

NASA Technical Reports Server (NTRS)

Lee, K.; Knepper, D. H.; Sawatzky, D. L.

1974-01-01

Extracting geologic information from ERTS and Skylab/EREP images is best done by a geologist trained in photo-interpretation. The information is at a regional scale, and three basic types are available: rock and soil, geologic structures, and landforms. Discrimination between alluvium and sedimentary or crystalline bedrock, and between units in thick sedimentary sequences is best, primarily because of topographic expression and vegetation differences. Discrimination between crystalline rock types is poor. Folds and fractures are the best displayed geologic features. They are recognizable by topographic expression, drainage patterns, and rock or vegetation tonal patterns. Landforms are easily discriminated by their familiar shapes and patterns. Several examples demonstrate the applicability of satellite images to tectonic analysis and petroleum and mineral exploration.

Surface features on Mars: Ground-based albedo and radar compared with Mariner 9 topography

NASA Technical Reports Server (NTRS)

Frey, H.

1973-01-01

Earth-based albedo maps of Mars were compared with Mariner 9 television data and ground-based radar profiles to investigate the nature of the bright and dark albedo features. Little correlation was found except at the boundaries of classical albedo features, where some topographic control is indicated. Wind-blown dust models for seasonal and secular albedo variations are supported, but it is not clear whether the fines are derived from bright or dark parent rock. Mars, like the Earth and Moon, has probably generated two distinct types of crustal material.

Forest resources of north Arkansas delta

Treesearch

I.F. Eldredge

1938-01-01

The North Arkansas Delta survey unit includes the flood plains of the Mississippi River and its principal tributaries between Helena, Arkansas, and Cape Girardeau, Missouri, with boundaries as shown in figure 1. Although chiefly in Arkansas, it includes portions of Missouri, Tennessee, and Kentucky. A conspicuous topographic feature is Crowley's Ridge, a narrow...

Spatio-temporal patterns of soil water storage under dryland agriculture at the watershed scale

USDA-ARS?s Scientific Manuscript database

Soil water patterns vary significantly due to precipitation, soil properties, topographic features, and land use. We used empirical orthogonal function (EOF) analysis to characterize the spatial variability of soil water across a 37-ha field of the Washington State University Cook Agronomy Farm near...

Magellan Perspective View of Ovda Regio, 15° N, 77° E

NASA Image and Video Library

1998-06-04

This perspective view of Venus, generated by computer from NASA Magellan data and color-coded with emissivity, shows part of the lowlands to the north of Ovda Regio. The prominent topographic feature is a shield volcano. http://photojournal.jpl.nasa.gov/catalog/PIA00308

Large Impact Features on Saturn's Middle-sized Icy Satellites: Global Image Mosaics and Topography

NASA Astrophysics Data System (ADS)

Schenk, P. M.; Moore, J. M.; McKinnon, W. B.

2003-03-01

New topographic maps of Saturn's middle-sized icy satellites derived from stereo imaging and 2D photoclinometry provide a sneak peak at the surprises in store when Cassini arrives at Saturn. We reexamine the morphology of large impact craters and describe their relaxation state.

Mapping Secondary Forest Succession on Abandoned Agricultural Land in the Polish Carpathians

NASA Astrophysics Data System (ADS)

Kolecka, N.; Kozak, J.; Kaim, D.; Dobosz, M.; Ginzler, Ch.; Psomas, A.

2016-06-01

Land abandonment and secondary forest succession have played a significant role in land cover changes and forest cover increase in mountain areas in Europe over the past several decades. Land abandonment can be easily observed in the field over small areas, but it is difficult to map over the large areas, e.g., with remote sensing, due to its subtle and spatially dispersed character. Our previous paper presented how the LiDAR (Light Detection and Ranging) and topographic data were used to detect secondary forest succession on abandoned land in one commune located in the Polish Carpathians by means of object-based image analysis (OBIA) and GIS (Kolecka et al., 2015). This paper proposes how the method can be applied to efficiently map secondary forest succession over the entire Polish Carpathians, incorporating spatial sampling strategy supported by various ancillary data. Here we discuss the methods of spatial sampling, its limitations and results in the context of future secondary forest succession modelling.

Surface topography regulates wnt signaling through control of primary cilia structure in mesenchymal stem cells

PubMed Central

McMurray, R. J.; Wann, A. K. T.; Thompson, C. L.; Connelly, J. T.; Knight, M. M.

2013-01-01

The primary cilium regulates cellular signalling including influencing wnt sensitivity by sequestering β-catenin within the ciliary compartment. Topographic regulation of intracellular actin-myosin tension can control stem cell fate of which wnt is an important mediator. We hypothesized that topography influences mesenchymal stem cell (MSC) wnt signaling through the regulation of primary cilia structure and function. MSCs cultured on grooves expressed elongated primary cilia, through reduced actin organization. siRNA inhibition of anterograde intraflagellar transport (IFT88) reduced cilia length and increased active nuclear β-catenin. Conversely, increased primary cilia assembly in MSCs cultured on the grooves was associated with decreased levels of nuclear active β-catenin, axin-2 induction and proliferation, in response to wnt3a. This negative regulation, on grooved topography, was reversed by siRNA to IFT88. This indicates that subtle regulation of IFT and associated cilia structure, tunes the wnt response controlling stem cell differentiation. PMID:24346024

Typical Applications of Airborne LIDAR Technolagy in Geological Investigation

NASA Astrophysics Data System (ADS)

Zheng, X.; Xiao, C.

2018-05-01

The technology of airborne light detection and ranging (LiDAR), also referred to as Airborne Laser Scanning, is widely used for high-resolution topographic data acquisition (even under forest cover) with sub-meter planimetric and vertical accuracy. This contribution constructs the real digital terrain model to provide the direct observation data for the landscape analysis in geological domains. Based on the advantage of LiDAR, the authors mainly deal with the applications of LiDAR data to such fields as surface land collapse, landslide and fault structure extraction. The review conclusion shows that airborne LiDAR technology is becoming an indispensable tool for above mentioned issues, especially in the local and large scale investigations of micro-topography. The technology not only can identify the surface collapse, landslide boundary and subtle faulted landform, but also be able to extract the filling parameters of collapsed surface, the geomorphic parameters of landslide stability evaluation and cracks. This technology has extensive prospect of applications in geological investigation.

The effects of titanium nitride-coating on the topographic and biological features of TPS implant surfaces.

PubMed

Annunziata, Marco; Oliva, Adriana; Basile, Maria Assunta; Giordano, Michele; Mazzola, Nello; Rizzo, Antonietta; Lanza, Alessandro; Guida, Luigi

2011-11-01

Titanium nitride (TiN) coating has been proposed as an adjunctive surface treatment aimed to increase the physico-mechanical and aesthetic properties of dental implants. In this study we investigated the surface characteristics of TiN-coated titanium plasma sprayed (TiN-TPS) and uncoated titanium plasma sprayed (TPS) surfaces and their biological features towards both primary human bone marrow mesenchymal stem cells (BM-MSC) and bacterial cultures. 15 mm×1 mm TPS and TiN-TPS disks (P.H.I. s.r.l., San Vittore Olona, Milano, Italy) were topographically analysed by confocal optical profilometry. Primary human BM-MSC were obtained from healthy donors, isolated and expanded. Cells were seeded on the titanium disks and cell adhesion, proliferation, protein synthesis and osteoblastic differentiation in terms of alkaline phosphatase activity, osteocalcin synthesis and extracellular mineralization, were evaluated. Furthermore, adhesion and proliferation of Streptococcus pyogenes and Streptococcus sanguinis on both surfaces were also analysed. TiN-TPS disks showed a decreased roughness (about 50%, p < 0.05) and a decreased bacterial adhesion and proliferation compared to TPS ones. No difference (p > 0.05) in terms of BM-MSC adhesion, proliferation and osteoblastic differentiation between TPS and TiN-TPS surfaces was found. TiN coating showed to modify the topographical characteristics of TPS titanium surfaces and to significantly reduce bacterial adhesion and proliferation, although maintaining their biological affinity towards bone cell precursors. Copyright © 2011 Elsevier Ltd. All rights reserved.

Controls on the spatial variability of supraglacial channel morphology and network characteristics

NASA Astrophysics Data System (ADS)

King, L.

2015-12-01

Supraglacial streams are widespread and ubiquitous features of glacial ice surfaces around the world. They play an important role in the spatial and temporal distribution of meltwater on a glacier, moderating the flux of meltwater to the bed. They are themselves unique fluvial features in which erosion and deposition is achieved through thermal erosion of ice rather than alluvial substrate. As such, they are of both glaciological and fluvial geomorphological interest for both practical and theoretical reasons. However, little is known about their characteristics through space and time, or how these characteristics reflect external driving forces. This research aims to address these gaps by characterizing the spatial variability of supraglacial stream morphology across a range of glacier types and environmental conditions and identifying forcings that control channel form. Topographic data was analyzed from a range of glacier surface types including icesheets, pocket alpine glaciers, and outlet valley glaciers spanning a range of latitudes and elevations, comprising glaciers from Greenland, British Columbia, Alaska, Iceland and Sweden. Channels were extracted from the topographic data using an automated approach based on identifying topographic depressions at different size scales, in which the method was tested relative to manually digitized stream networks. Channel geomorphology was subsequently characterized according to planimetric and drainage network geometries. Resulting morphometric characteristics were analyzed with regards to endo and exogenic environmental forcings such as ice topography and characteristics and climatic forcings to identify the primary controls on supraglacial channel morphology and the response of these channels with respect to these controls.

Magnetic, gravity, radiometric, LiDAR, and seismic data to characterize the region of the M5.8 August 23, 2011 earthquake near Mineral, Virginia

NASA Astrophysics Data System (ADS)

Shah, A. K.; McNamara, D. E.; Odum, J. K.; Stephenson, W. J.; Kayen, R. E.; Emmett, P. F.; Herrmann, R. B.; Snyder, S. L.; Horton, J. W.; Williams, R. A.

2012-12-01

In response to the M5.8 August 23, 2011 Mineral, VA earthquake, the U.S. Geological Survey and partner organizations acquired or sponsored collection of several geophysical datasets to assist characterization of the earthquake region. Goals include the mapping of the main shock causative and aftershock faults as well as associated geologic features which may be buried or difficult to access, estimates of regional ground motion attenuation, and measurements describing local amplification of seismic energy. The deployment of 46 portable seismic stations by several organizations within days following the earthquake, along with public availability of the resulting data, has greatly aided site characterization efforts. The aftershock data recorded by these stations have allowed delineation of the probable causative fault and other faults that were active afterwards. Using the portable seismograph network and regional permanent stations, S and Lg waves were analyzed to estimate crustal attenuation characteristics. Active- and passive-source seismic experiments were also conducted at many of the portable and permanent stations to characterize site conditions and constrain local response models via estimates of Vs30 and bedrock depth. In March 2012, a LiDAR survey with 8pt/m2 resolution was flown over a ~20x35 km area covering the epicenters of the earthquake and most aftershocks. In July 2012, a high-resolution airborne magnetic, gravity, and radiometric survey was flown over a similar but slightly smaller area. Supplementary ground gravity data have been collected inside and outside of the airborne survey areas. The gravity and magnetic data reflect subsurface features in a region where outcropping rocks are sparse, while LiDAR and radiometric data, respectively, delineate subtle features at the land surface and upper few centimeters. Each of these datasets reflects the regional NE-SW striking fabric. Seismic wave analyses show preferential attenuation in a NW-SE direction, perpendicular to major structures and consistent with estimates of motion intensity such as USGS "Did you feel it?" website responses and local damage reports (Virginia DMME). Preliminary analyses of strong ground motions show measurable differences in shaking over scales of kilometers. Magnetic data show numerous NE-SW lineations, some which extend several tens of km to the northeast from near the aftershock plane, suggesting continuity of some features in that direction. Near the earthquake epicenter and primary aftershock plane, small changes in the orientation of major structures (< 20°) are apparent in magnetic, gravity and topographic data. Detailed analyses to understand possible relations are underway.

Features and dimensions of the Hayward Fault Zone in the Strawberry and Blackberry Creek Area, Berkeley, California

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

Williams, P.L.

1995-03-01

This report presents an examination of the geometry of the Hayward fault adjacent to the Lawrence Berkeley Laboratory and University of California campuses in central Berkeley. The fault crosses inside the eastern border of the UC campus. Most subtle geomorphic (landform) expressions of the fault have been removed by development and by the natural processes of landsliding and erosion. Some clear expressions of the fault remain however, and these are key to mapping the main trace through the campus area. In addition, original geomorphic evidence of the fault`s location was recovered from large scale mapping of the site dating frommore » 1873 to 1897. Before construction obscured and removed natural landforms, the fault was expressed by a linear, northwest-tending zone of fault-related geomorphic features. There existed well-defined and subtle stream offsets and beheaded channels, fault scarps, and a prominent ``shutter ridge``. To improve our confidence in fault locations interpreted from landforms, we referred to clear fault exposures revealed in trenching, revealed during the construction of the Foothill Housing Complex, and revealed along the length of the Lawson Adit mining tunnel. Also utilized were the locations of offset cultural features. At several locations across the study area, distress features in buildings and streets have been used to precisely locate the fault. Recent published mapping of the fault (Lienkaemper, 1992) was principally used for reference to evidence of the fault`s location to the northwest and southeast of Lawrence Berkeley Laboratory.« less

The Influence of Social Cues and Cognitive Processes in Computer Mediated Second Language Learning

ERIC Educational Resources Information Center

Murakami, Janel Rachel Goodman

2017-01-01

This dissertation investigated the effects of technological mediation on second language (L2) learning, focusing, as a case study, on gains in listening perception of the subtle but important feature of pitch placement in Japanese. Pitch accent can be difficult to perceive for non-native speakers whose first language (L1) does not rely on pitch or…

The Breast Health Intervention Evaluation Study

DTIC Science & Technology

2001-08-01

content due to its subtle almost subliminal impact even though this issue did not surface in the various pre-tests during video development. A third...A. (1990). Involuntary attention and physiological arousal evoked by structural features and emotional content in TV commercials. Communication...Human communication research, 13, 399-420. Pezdek, K., and Stevens, E. (1984). Children=s memory for auditory and visual information on television

Detection of CN emission from (2060) Chiron

NASA Technical Reports Server (NTRS)

Bowell, Edward

1991-01-01

Spectrophotometric observations of (2060) Chiron were obtained. Their primary goal was to look for the subtle differences in color between Chiron and its surrounding coma, and to search for possible absorption or emission features in Chiron's spectrum. The presence of the CN(0-0) emission band was identified. It proves Chiron's cometary nature and breaks the record heliocentric distance for cometary gaseous emission.

Evolution of certain typical and atypical features in a case of subacute sclerosing panencephalitis

PubMed Central

Raut, Tushar Premraj; Singh, Maneesh Kumar; Garg, Ravindra Kumar; Rai, Dheeraj

2012-01-01

Subacute sclerosing panencephalitis (SSPE) is a slowly progressive inflammatory disease of the central nervous system caused by a persistent measles virus usually affecting the childhood and adolescent age group. Clinical features at onset are very subtle and non-specific. Certain atypical features can occur at onset or during the course of illness which can be misleading. Neuroimaging features often are non-specific. Features like myoclonic jerks, cognitive decline and typical EEG findings lead to a strong suspicion of SSPE. Here, we describe the stagewise progression of a case of SSPE in a 14-year-old girl who had myoclonic jerks and cognitive decline at onset. During the course of disease, the patient developed cortical vision loss, atypical extrapyramidal features like segmental and hemifacial dystonia ultimately leading to a bedbound vegetative state. EEG showed typical periodic discharges along with positive cerebrospinal fluid serology for measles. PMID:23266775

Evolution of certain typical and atypical features in a case of subacute sclerosing panencephalitis.

PubMed

Raut, Tushar Premraj; Singh, Maneesh Kumar; Garg, Ravindra Kumar; Rai, Dheeraj

2012-12-23

Subacute sclerosing panencephalitis (SSPE) is a slowly progressive inflammatory disease of the central nervous system caused by a persistent measles virus usually affecting the childhood and adolescent age group. Clinical features at onset are very subtle and non-specific. Certain atypical features can occur at onset or during the course of illness which can be misleading. Neuroimaging features often are non-specific. Features like myoclonic jerks, cognitive decline and typical EEG findings lead to a strong suspicion of SSPE. Here, we describe the stagewise progression of a case of SSPE in a 14-year-old girl who had myoclonic jerks and cognitive decline at onset. During the course of disease, the patient developed cortical vision loss, atypical extrapyramidal features like segmental and hemifacial dystonia ultimately leading to a bedbound vegetative state. EEG showed typical periodic discharges along with positive cerebrospinal fluid serology for measles.

A switch from parallel to antiparallel strand orientation in a coiled-coil X-ray structure via two core hydrophobic mutations

DOE PAGES

Malashkevich, Vladimir N.; Higgins, Chelsea D.; Almo, Steven C.; ...

2015-05-06

The coiled-coil is one of the most ubiquitous and well studied protein structural motifs. Significant effort has been devoted to dissecting subtle variations of the typical heptad repeat sequence pattern that can designate larger topological features such as relative α-helical orientation and oligomer size. Here in this paper we report the X-ray structure of a model coiled-coil peptide, HA2-Del-L2seM, which forms an unanticipated core antiparallel dimer with potential sites for discrete higher-order multimerization (trimer or tetramer). In the X-ray structure, a third, partially-ordered α-helix is weakly associated with the antiparallel dimer and analytical ultracentrifugation experiments indicate the peptide forms amore » well-defined tetramer in solution. The HA2-Del-L2seM sequence is closely related to a parent model peptide, HA2-Del, which we previously reported adopts a parallel trimer; HA2-Del-L2seM differs by only hydrophobic leucine to selenomethione mutations and thus this subtle difference is sufficient to switch both relative α-helical topology and number of α-helices participating in the coiled-coil. Comparison of the X-ray structures of HA2-Del-L2seM (reported here) with the HA2-Del parent (reported previously) reveals novel interactions involving the selenomethionine residues that promote antiparallel coiled-coil configuration and preclude parallel trimer formation. Finally, these novel atomic insights are instructive for understanding subtle features that can affect coiled-coil topology and provide additional information for design of antiparallel coiled-coils.« less

Diagnosing subtle palatal anomalies: Validation of video-analysis and assessment protocol for diagnosing occult submucous cleft palate.

PubMed

Rourke, Ryan; Weinberg, Seth M; Marazita, Mary L; Jabbour, Noel

2017-09-01

Submucous cleft palate (SMCP) classically involves bifid uvula, zona pellucida, and notched hard palate. However, patients may present with more subtle anatomic abnormalities. The ability to detect these abnormalities is important for surgeons managing velopharyngeal dysfunction (VPD) or considering adenoidectomy. Validate an assessment protocol for diagnosis of occult submucous cleft palate (OSMCP) and identify physical examination features present in patients with OSMCP in the relaxed and activated palate positions. Study participants included patients referred to a pediatric VPD clinic with concern for hypernasality or SMCP. Using an appropriately encrypted iPod touch, transoral video was obtained for each patient with the palate in the relaxed and activated positions. The videos were reviewed by two otolaryngologists in normal speed and slow-motion, as needed, and a questionnaire was completed by each reviewer pertaining to the anatomy and function of the palate. 47 patients, with an average age of 4.6 years, were included in the study over a one-year period. Four videos were unusable due to incomplete view of the palate. The most common palatal abnormality noted was OSMCP, diagnosed by each reviewer in 26/43 and 30/43 patients respectively. Using the assessment protocol, agreement on palatal diagnosis was 83.7% (kappa = 0.68), indicating substantial agreement, with the most prevalent anatomic features being vaulted palate elevation (96%) and visible notching of hard palate (75%). The diagnosis of subtle palatal anomalies is difficult and can be subjective. Using the proposed video-analysis method and assessment protocol may improve reliability of diagnosis of OSMCP. Copyright © 2017 Elsevier B.V. All rights reserved.

GEOGRAPHIC NAMES INFORMATION SYSTEM (GNIS) ...

EPA Pesticide Factsheets

The Geographic Names Information System (GNIS), developed by the U.S. Geological Survey in cooperation with the U.S. Board on Geographic Names (BGN), contains information about physical and cultural geographic features in the United States and associated areas, both current and historical, but not including roads and highways. The database also contains geographic names in Antarctica. The database holds the Federally recognized name of each feature and defines the location of the feature by state, county, USGS topographic map, and geographic coordinates. Other feature attributes include names or spellings other than the official name, feature designations, feature class, historical and descriptive information, and for some categories of features the geometric boundaries. The database assigns a unique feature identifier, a random number, that is a key for accessing, integrating, or reconciling GNIS data with other data sets. The GNIS is our Nation's official repository of domestic geographic feature names information.

Improving the Inventory of Large Lunar Basins: Using LOLA Data to Test Previous Candidates and Search for New Ones

NASA Technical Reports Server (NTRS)

Frey, H. V.; Meyer, H. M.; Romine, G. C.

2012-01-01

Topography and crustal thickness data from LOLA altimetry were used to test the validity of 98 candidate large lunar basins derived from photogeologic and earlier topographic and crustal thickness data, and to search for possible new candidates. We eliminate 23 previous candidates but find good evidence for 20 new candidates. The number of basins greater than 300 km diameter on the Moon is almost certainly a factor 2 (maybe 3?) larger than the number of named features having basin-like topography. Unified Lunar Control Net 2005 data [1] and model crustal thickness data [2] were previously used to search for possible previously unrecognized large lunar impact basins [3,4]. An inventory of 98 candidate topographic basins greater than 300 km in diameter was found [5]. This includes 33 named features (only those having basin-like topography) out of the 45 listed by Wilhelms [6], 38 additional Quasi-Circular Depressions (QCDs) found in the ULCN2005 topography, and 27 Circular Thin Areas (CTAs) found in model crustal thickness data [2]. Most named features and additional QCDs have strong CTA signatures, but there may be a class of CTAs that are not easily recognized in the old and low resolution ULCN2005 topography. Lunar Orbiter Laser Altimeter (LOLA) data have recently become publically available. We used these data to (a) refine the center and ring diameters of known basins, (b) test the viability of the candidate basins previously found (as described above), and (c) search for additional candidate basins not revealed by the earlier lower resolution data. We used the LOLA topography directly but also a recent new model crustal thickness data that includes Kaguya gravity data [7]. We repeated a Topographic Expression (TE) and a Crustal Thickness Expression (CTE) scoring exercise originally done with the basins found in ULCN and earlier model crustal thickness data [5]. Each candidate was scored on a scale from 0 (no topographic basin or circular thin area signature) to 5 (strong circular low or strong circular thin area signature). These were combined into a total score used to rank the probability for each candidate basin. We used the same GRIDVIEW software to stretch, contour and profile the LOLA and new crustal thickness data as was done with the ULCN2005 and older model crustal thickness data.

Photonic integrated circuits: new challenges for lithography

NASA Astrophysics Data System (ADS)

Bolten, Jens; Wahlbrink, Thorsten; Prinzen, Andreas; Porschatis, Caroline; Lerch, Holger; Giesecke, Anna Lena

2016-10-01

In this work routes towards the fabrication of photonic integrated circuits (PICs) and the challenges their fabrication poses on lithography, such as large differences in feature dimension of adjacent device features, non-Manhattan-type features, high aspect ratios and significant topographic steps as well as tight lithographic requirements with respect to critical dimension control, line edge roughness and other key figures of merit not only for very small but also for relatively large features, are highlighted. Several ways those challenges are faced in today's low-volume fabrication of PICs, including the concept multi project wafer runs and mix and match approaches, are presented and possible paths towards a real market uptake of PICs are discussed.

Delineating wetland catchments and modeling hydrologic connectivity using lidar data and aerial imagery

NASA Astrophysics Data System (ADS)

Wu, Qiusheng; Lane, Charles R.

2017-07-01

In traditional watershed delineation and topographic modeling, surface depressions are generally treated as spurious features and simply removed from a digital elevation model (DEM) to enforce flow continuity of water across the topographic surface to the watershed outlets. In reality, however, many depressions in the DEM are actual wetland landscape features with seasonal to permanent inundation patterning characterized by nested hierarchical structures and dynamic filling-spilling-merging surface-water hydrological processes. Differentiating and appropriately processing such ecohydrologically meaningful features remains a major technical terrain-processing challenge, particularly as high-resolution spatial data are increasingly used to support modeling and geographic analysis needs. The objectives of this study were to delineate hierarchical wetland catchments and model their hydrologic connectivity using high-resolution lidar data and aerial imagery. The graph-theory-based contour tree method was used to delineate the hierarchical wetland catchments and characterize their geometric and topological properties. Potential hydrologic connectivity between wetlands and streams were simulated using the least-cost-path algorithm. The resulting flow network delineated potential flow paths connecting wetland depressions to each other or to the river network on scales finer than those available through the National Hydrography Dataset. The results demonstrated that our proposed framework is promising for improving overland flow simulation and hydrologic connectivity analysis.

Landscape determinants of fine-scale genetic structure of a small rodent in a heterogeneous landscape (Hluhluwe-iMfolozi Park, South Africa)

PubMed Central

Russo, Isa-Rita M.; Sole, Catherine L.; Barbato, Mario; von Bramann, Ullrich; Bruford, Michael W.

2016-01-01

Small mammals provide ecosystem services, acting, for example, as pollinators and seed dispersers. In addition, they are also disease reservoirs that can be detrimental to human health and they can also act as crop pests. Knowledge of their dispersal preferences is therefore useful for population management and landscape planning. Genetic data were used alongside landscape data to examine the influence of the landscape on the demographic connectedness of the Natal multimammate mouse (Mastomys natalensis) and to identify landscape characteristics that influence the genetic structure of this species across a spatially and temporally varying environment. The most significant landscape features shaping gene flow were aspect, vegetation cover, topographic complexity (TC) and rivers, with western facing slopes, topographic complexity and rivers restricting gene flow. In general, thicket vegetation was correlated with increased gene flow. Identifying features of the landscape that facilitate movement/dispersal in M. natalensis potentially has application for other small mammals in similar ecosystems. As the primary reservoir host of the zoonotic Lassa virus, a landscape genetics approach may have applications in determining areas of high disease risk to humans. Identifying these landscape features may also be important in crop management due to damage by rodent pests. PMID:27406468

Landscape determinants of fine-scale genetic structure of a small rodent in a heterogeneous landscape (Hluhluwe-iMfolozi Park, South Africa).

PubMed

Russo, Isa-Rita M; Sole, Catherine L; Barbato, Mario; von Bramann, Ullrich; Bruford, Michael W

2016-07-13

Small mammals provide ecosystem services, acting, for example, as pollinators and seed dispersers. In addition, they are also disease reservoirs that can be detrimental to human health and they can also act as crop pests. Knowledge of their dispersal preferences is therefore useful for population management and landscape planning. Genetic data were used alongside landscape data to examine the influence of the landscape on the demographic connectedness of the Natal multimammate mouse (Mastomys natalensis) and to identify landscape characteristics that influence the genetic structure of this species across a spatially and temporally varying environment. The most significant landscape features shaping gene flow were aspect, vegetation cover, topographic complexity (TC) and rivers, with western facing slopes, topographic complexity and rivers restricting gene flow. In general, thicket vegetation was correlated with increased gene flow. Identifying features of the landscape that facilitate movement/dispersal in M. natalensis potentially has application for other small mammals in similar ecosystems. As the primary reservoir host of the zoonotic Lassa virus, a landscape genetics approach may have applications in determining areas of high disease risk to humans. Identifying these landscape features may also be important in crop management due to damage by rodent pests.

AlphaSpace: Fragment-Centric Topographical Mapping To Target Protein–Protein Interaction Interfaces

PubMed Central

2016-01-01

Inhibition of protein–protein interactions (PPIs) is emerging as a promising therapeutic strategy despite the difficulty in targeting such interfaces with drug-like small molecules. PPIs generally feature large and flat binding surfaces as compared to typical drug targets. These features pose a challenge for structural characterization of the surface using geometry-based pocket-detection methods. An attractive mapping strategy—that builds on the principles of fragment-based drug discovery (FBDD)—is to detect the fragment-centric modularity at the protein surface and then characterize the large PPI interface as a set of localized, fragment-targetable interaction regions. Here, we introduce AlphaSpace, a computational analysis tool designed for fragment-centric topographical mapping (FCTM) of PPI interfaces. Our approach uses the alpha sphere construct, a geometric feature of a protein’s Voronoi diagram, to map out concave interaction space at the protein surface. We introduce two new features—alpha-atom and alpha-space—and the concept of the alpha-atom/alpha-space pair to rank pockets for fragment-targetability and to facilitate the evaluation of pocket/fragment complementarity. The resulting high-resolution interfacial map of targetable pocket space can be used to guide the rational design and optimization of small molecule or biomimetic PPI inhibitors. PMID:26225450

The initial instability and finite-amplitude stability of alternate bars in straight channels

USGS Publications Warehouse

Nelson, J.M.

1990-01-01

The initial instability and fully developed stability of alternate bars in straight channels are investigated using linearized and nonlinear analyses. The fundamental instability leading to these features is identified through a linear stability analysis of the equations governing the flow and sediment transport fields. This instability is explained in terms of topographically induced steering of the flow and the associated pattern of erosion and deposition on the bed. While the linear theory is useful for examining the instability mechanism, this approach is shown to yield relatively little information about well-developed alternate bars and, specifically, the linear analysis is shown to yield poor predictions of the fully developed bar wavelength. A fully nonlinear approach is presented that permits computation of the evolution of these bed features from an initial perturbation to their fully developed morphology. This analysis indicates that there is typically substantial elongation of the bar wavelength during the evolution process, a result that is consistent with observations of bar development in flumes and natural channels. The nonlinear approach demonstrates that the eventual stability of these features is a result of the interplay between topographic steering effects, secondary flow production as a result of streamline curvature, and gravitationally induced modifications of sediment fluxes over a sloping bed. ?? 1990.

A reassessment of the role of tidal dispersion in estuaries and bays

USGS Publications Warehouse

Geyer, W. Rockwell; Signell, Richard P.

1992-01-01

The role of tidal dispersion is reassessed, based on a consideration of the relevant physical mechanisms, particularly those elucidated by numerical simulations of tide-induced dispersion. It appears that the principal influence of tidal currents on dispersion occurs at length scales of the tidal excursion and smaller; thus the effectiveness of tidal dispersion depends on the relative scale of the tidal excursion to the spacing between major bathymetric and shoreline features. In estuaries where the typical spacing of topographic features is less than the tidal excursion, tidal dispersion may contribute significantly to the overall flushing. In estuaries and embayments in which the typical spacing between major features is larger than the tidal excursion, the influence of tidal dispersion will be localized, and it will not markedly contribute to overall flushing. Tidal dispersion is most pronounced in regions of abrupt topographic changes such as headlands and inlets, where flow separation occurs. The strong strain rate in the region of flow separation tends to stretch patches of fluid into long filaments, which are subsequently rolled up and distorted by the transient eddy field. The dispersion process accomplished by the tides varies strongly as a function of position and tidal phase and thus does not lend itself to parameterization by an eddy diffusion coefficient.

Isolated cortical visual loss with subtle brain MRI abnormalities in a case of hypoxic-ischemic encephalopathy.

PubMed

Margolin, Edward; Gujar, Sachin K; Trobe, Jonathan D

2007-12-01

A 16-year-old boy who was briefly asystolic and hypotensive after a motor vehicle accident complained of abnormal vision after recovering consciousness. Visual acuity was normal, but visual fields were severely constricted without clear hemianopic features. The ophthalmic examination was otherwise normal. Brain MRI performed 11 days after the accident showed no pertinent abnormalities. At 6 months after the event, brain MRI demonstrated brain volume loss in the primary visual cortex and no other abnormalities. One year later, visual fields remained severely constricted; neurologic examination, including formal neuropsychometric testing, was normal. This case emphasizes the fact that hypoxic-ischemic encephalopathy (HIE) may cause enduring damage limited to primary visual cortex and that the MRI abnormalities may be subtle. These phenomena should be recognized in the management of patients with HIE.

Mathematical Modelling of Arctic Polygonal Tundra with Ecosys: 2. Microtopography Determines How CO2 and CH4 Exchange Responds to Changes in Temperature and Precipitation

NASA Astrophysics Data System (ADS)

Grant, R. F.; Mekonnen, Z. A.; Riley, W. J.; Arora, B.; Torn, M. S.

2017-12-01

Differences of surface elevation in arctic polygonal landforms cause spatial variation in soil water contents (θ), active layer depths (ALD), and thereby in CO2 and CH4 exchange. Here we test hypotheses in ecosys for topographic controls on CO2 and CH4 exchange in trough, rim, and center features of low- and flat-centered polygons (LCP and FCP) against chamber and eddy covariance (EC) measurements during 2013 at Barrow, Alaska. Larger CO2 influxes and CH4 effluxes were measured with chambers and modeled with ecosys in LCPs than in FCPs and in lower features (troughs) than in higher (rims) within LCPs and FCPs. Spatially aggregated CO2 and CH4 fluxes from ecosys were significantly correlated with EC flux measurements. Lower features were modeled as C sinks (52-56 g C m-2 yr-1) and CH4 sources (4-6 g C m-2 yr-1), and higher features as near C neutral (-2-15 g C m-2 yr-1) and CH4 neutral (0.0-0.1 g C m-2 yr-1). Much of the spatial and temporal variations in CO2 and CH4 fluxes were modeled from topographic effects on water and snow movement and thereby on θ, ALD, and soil O2 concentrations. Model results forced with meteorological data from 1981 to 2015 indicated increasing net primary productivity in higher features and CH4 emissions in some lower and higher features since 2008, attributed mostly to recent rises in precipitation. Small-scale variation in surface elevation causes large spatial variation of greenhouse gas (GHG) exchanges and therefore should be considered in estimates of GHG exchange in polygonal landscapes.

Topologic analysis and comparison of brain activation in children with epilepsy versus controls: an fMRI study

NASA Astrophysics Data System (ADS)

Oweis, Khalid J.; Berl, Madison M.; Gaillard, William D.; Duke, Elizabeth S.; Blackstone, Kaitlin; Loew, Murray H.; Zara, Jason M.

2010-03-01

This paper describes the development of novel computer-aided analysis algorithms to identify the language activation patterns at a certain Region of Interest (ROI) in Functional Magnetic Resonance Imaging (fMRI). Previous analysis techniques have been used to compare typical and pathologic activation patterns in fMRI images resulting from identical tasks but none of them analyzed activation topographically in a quantitative manner. This paper presents new analysis techniques and algorithms capable of identifying a pattern of language activation associated with localization related epilepsy. fMRI images of 64 healthy individuals and 31 patients with localization related epilepsy have been studied and analyzed on an ROI basis. All subjects are right handed with normal MRI scans and have been classified into three age groups (4-6, 7-9, 10-12 years). Our initial efforts have focused on investigating activation in the Left Inferior Frontal Gyrus (LIFG). A number of volumetric features have been extracted from the data. The LIFG has been cut into slices and the activation has been investigated topographically on a slice by slice basis. Overall, a total of 809 features have been extracted, and correlation analysis was applied to eliminate highly correlated features. Principal Component analysis was then applied to account only for major components in the data and One-Way Analysis of Variance (ANOVA) has been applied to test for significantly different features between normal and patient groups. Twenty Nine features have were found to be significantly different (p<0.05) between patient and control groups

The Effect of Topographic Shadowing by Ice on Irradiance in the Greenland Ice Sheet Ablation Zone

NASA Astrophysics Data System (ADS)

Leidman, S. Z.; Rennermalm, A. K.; Ryan, J.; Cooper, M. G.; Smith, L. C.

2017-12-01

Accurately predicting runoff contributions to global sea level rise requires more refined surface mass balance (SMB) models of the Greenland Ice Sheet (GrIS). Topographic shadowing has shown to be important in the SMB of snow-covered regions, yet SMB models for the GrIS generally ignore how surface topography affects spatial variability of incoming solar radiation on a surface. In the ablation zone of Southwest Greenland, deeply incised supraglacial drainage features, fracturing, and large-scale bed deformation result in extensive areas of rough surface topography. This topography blocks direct radiation such that shadowed areas receive less energy for melting while other topographic features such as peaks recieve more energy. In this study, we quantify how shadowing from local topography features changes incoming solar radiation. We apply the ArcGIS Pro Solar Radiation Toolset to calculate the direct and diffuse irradiance in sunlit and shadowed areas by determining the sun's movement for every half hour increment of 2016. Multiple digital elevation models (DEMs) with spatial resolutions ranging from 0.06 to 5m were derived from fixed wing and quadcopter UAV imagery collected in summer 2016 and the ArcticDEM dataset. Our findings show that shadowing significantly decreases irradiance compared to smoothed surfaces where local topography is removed. This decrease is exponentially proportional to the DEM pixel sized with 5m DEMs only able to capture a small percentage of the effect. Applying these calculations to the ArcticDEM to cover a larger study area indicates that decreases in irradiance are nonlinearly proportional to elevation with highly crevassed areas showing a larger effect from shadowing. Even so, shading at higher elevations reduces irradiance enough to result in several centimeters snow water equivalence (SWE) per year of over-prediction of runoff in SMB models. Furthermore, analysis of solar radiation products shows that shadowing predicts albedo variability far better than a range of variables derived from UAV imagery mosaics including slope, aspect, elevation, or the distance to dark surface features. In summary, implementation of the effect of shadowing on irradiance should therefore be considered for accurate surface mass balance calculations for the Greenland ice sheet.

Global Geometric Properties of Martian Impact Craters: A Preliminary Assessment Using Mars Orbiter Laser Altimeter (MOLA)

NASA Technical Reports Server (NTRS)

Garvin, J. B.; Sakimoto, S. E. H.; Schnetzler, C.; Frawley, J. J.

1999-01-01

Impact craters on Mars have been used to provide fundamental insights into the properties of the martian crust, the role of volatiles, the relative age of the surface, and on the physics of impact cratering in the Solar System. Before the three-dimensional information provided by the Mars Orbiter Laser Altimeter (MOLA) instrument which is currently operating in Mars orbit aboard the Mars Global Surveyor (MGS), impact features were characterized morphologically using orbital images from Mariner 9 and Viking. Fresh-appearing craters were identified and measurements of their geometric properties were derived from various image-based methods. MOLA measurements can now provide a global sample of topographic cross-sections of martian impact features as small as approx. 2 km in diameter, to basin-scale features. We have previously examined MOLA cross-sections of Northern Hemisphere and North Polar Region impact features, but were unable to consider the global characteristics of these ubiquitous landforms. Here we present our preliminary assessment of the geometric properties of a globally-distributed sample of martian impact craters, most of which were sampled during the initial stages of the MGS mapping mission (i.e., the first 600 orbits). Our aim is to develop a framework for reconsidering theories concerning impact cratering in the martian environment. This first global analysis is focused upon topographically-fresh impact craters, defined here on the basis of MOLA topographic profiles that cross the central cavities of craters that can be observed in Viking-based MDIM global image mosaics. We have considered crater depths, rim heights, ejecta topologies, cross-sectional "shapes", and simple physical models for ejecta emplacement. To date (May, 1999), we have measured the geometric properties of over 1300 impact craters in the 2 to 350 km diameter size interval. A large fraction of these measured craters were sampled with cavity-center cross-sections during the first two months of MGS mapping. Many of these craters are included in Nadine Barlow's Catalogue of Martian Impact Craters, although we have treated simple craters smaller than about 7 km in greater detail than all previous investigations. Additional information is contained in the original extended abstract.

Modeling Seasonal Thermal Radiance Cycles for Change Detection at Volcanic / Geothermal Areas

NASA Astrophysics Data System (ADS)

Vaughan, R.; Beuttel, B. S.

2013-12-01

Remote sensing observations of thermal features associated with (and often preceding) volcanic activity have been used for decades to detect and monitor volcanism. However, anomalous thermal precursors to volcanic eruptions are usually only recognized retrospectively. One of the reasons for this is that precursor thermal activity is often too subtle in magnitude (spatially, temporally, or in absolute temperature) to be unambiguously detected in time to issue warnings or forecasts. Part of the reason for this is the trade-off between high spatial and high temporal resolution associated with satellite imaging systems. Thus, the goal of this work has been to develop some techniques for using high-temporal-resolution, coarse-spatial-resolution imagery to try to detect subtle thermal anomalies. To identify anomalies, background thermal activity must first be characterized. Every active, or potentially active, volcano has a unique thermal history that provides information about normal background thermal activity due to seasonal or diurnal variations. Understanding these normal variations allows recognition of anomalous activity that may be due to volcanic / hydrothermal processes - ultimately with a lead time that may be sufficient to issue eruption warnings or forecasts. Archived MODIS data, acquired ~daily from 2000 to 2012, were used to investigate seasonal thermal cycles at three volcanic areas with different types of thermal features: Mount St. Helens, which had a dacite dome-building eruption from 2004-2008; Mount Ruapehu, which has a 500-m diameter active summit crater lake; and Yellowstone, which is a large active geothermal system that has hundreds of hot springs and fumarole fields spread out over a very large area. The focus has been on using MODIS 1-km sensor radiance data in the MIR and TIR wavelength regions that are sensitive to thermal emission from features that range in temperature from hundreds of °C, down to tens of °C (below the boiling temperature of water). To detect such features it is best to use data acquired at night, as this maximizes the delta T between the thermal target and non-thermal background and minimizes the effects of the Sun. Decadal time-series plots of nighttime MODIS sensor radiance data over the target areas show that seasonal thermal cycles due to varying solar incidence angle can be modeled with a sine function and removed to reveal subtle changes in TIR radiance. The seasonal sine function is unique to each volcanic / geothermal area and can be modeled iteratively using a least squares fit to the cloud of radiance data. The sine function model can also be used to generate a first-order cloud cover approximation for the nighttime TIR data. This work helps establish a framework for improved thermal alarm algorithms, automated thermal detection methods, and operational monitoring techniques for active, or potentially active, volcanoes throughout the world. This type of background study is a step toward establishing a global volcanic eruption forecasting system using satellite-based remote sensing data that are sensitive to subtle precursor thermal anomalies.

Development and Utilization of Regional Oceanic Modeling System (ROMS). Delicacy, Imprecision, and Uncertainty of Oceanic Simulations: An Investigation with the Regional Oceanic Modeling System (ROMS). Submesoscale Flows and Mixing in the Ocean Surface Layer Using the Regional Oceanic Modeling System (ROMS). Eddy Effects in General Circulation, Spanning Mean Currents, Mesoscale Eddies, and Topographic Generation, including Submesoscale Nests

DTIC Science & Technology

2012-09-30

unbalanced motions is likely to occur. Due to an rapidly expanding set of investigation on oceanic flows at submesoscales, it is increasingly clear...Uchiyama, E. M. Lane, J. M. Restrepo, & J. C. McWilliams, 2011: A vortex force analysis of the interaction of rip currents and gravity waves. J. Geophys...particular topographic features, the torque is pervasively positive (cyclonic) along the Stream, in opposition to the anticyclonic wind curl in the

Multidimensional nanomaterials for the control of stem cell fate

NASA Astrophysics Data System (ADS)

Chueng, Sy-Tsong Dean; Yang, Letao; Zhang, Yixiao; Lee, Ki-Bum

2016-09-01

Current stem cell therapy suffers low efficiency in giving rise to differentiated cell lineages, which can replace the original damaged cells. Nanomaterials, on the other hand, provide unique physical size, surface chemistry, conductivity, and topographical microenvironment to regulate stem cell differentiation through multidimensional approaches to facilitate gene delivery, cell-cell, and cell-ECM interactions. In this review, nanomaterials are demonstrated to work both alone and synergistically to guide selective stem cell differentiation. From three different nanotechnology families, three approaches are shown: (1) soluble microenvironmental factors; (2) insoluble physical microenvironment; and (3) nano-topographical features. As regenerative medicine is heavily invested in effective stem cell therapy, this review is inspired to generate discussions in the potential clinical applications of multi-dimensional nanomaterials.

Functions of the human frontoparietal attention network: Evidence from neuroimaging

PubMed Central

Scolari, Miranda; Seidl-Rathkopf, Katharina N; Kastner, Sabine

2016-01-01

Human frontoparietal cortex has long been implicated as a source of attentional control. However, the mechanistic underpinnings of these control functions have remained elusive due to limitations of neuroimaging techniques that rely on anatomical landmarks to localize patterns of activation. The recent advent of topographic mapping via functional magnetic resonance imaging (fMRI) has allowed the reliable parcellation of the network into 18 independent subregions in individual subjects, thereby offering unprecedented opportunities to address a wide range of empirical questions as to how mechanisms of control operate. Here, we review the human neuroimaging literature that has begun to explore space-based, feature-based, object-based and category-based attentional control within the context of topographically defined frontoparietal cortex. PMID:27398396

Soil moisture gradients and controls on a southern Appalachian hillslope from drought through recharge

Treesearch

J.A. Yeakley; W.T. Swank; L.W. Swift; G.M. Hornberger; H.H. Shugart

1998-01-01

Soil moisture gradients along hillslopes in humid watersheds, although indicated by vegetation gradients and by studies using models, have been difficult to confirm empirically. While soil properties and topographic features are the two general physiographic factors controlling soil moisture on hillslopes, studies have shown conflicting results regarding which factor...

Southern Appalachian hillslope erosion rates measured by soil and detrital radiocarbon in hollows

Treesearch

T.C. Hales; K.M. Scharer; R.M. Wooten

2012-01-01

Understanding the dynamics of sediment generation and transport on hillslopes provides important constraints on the rate of sediment output from orogenic systems. Hillslope sediment fluxes are recorded by organic material found in the deposits infilling unchanneled convergent topographic features called hollows. This study describes the first hollow infilling rates...

14 CFR 77.15 - Construction or alteration not requiring notice.

Code of Federal Regulations, 2010 CFR

2010-01-01

... existing structures of a permanent and substantial character or by natural terrain or topographic features... where it is evident beyond all reasonable doubt that the structure so shielded will not adversely affect safety in air navigation. (b) Any antenna structure of 20 feet or less in height except one that would...

The control of palaeo-topography in the preservation of shallow gas accumulation: Examples from Brazil, Argentina and South Africa

NASA Astrophysics Data System (ADS)

Weschenfelder, Jair; Klein, Antonio H. F.; Green, Andrew N.; Aliotta, Salvador; de Mahiques, Michel M.; Ayres Neto, Arthur; Terra, Laurício C.; Corrêa, Iran C. S.; Calliari, Lauro J.; Montoya, Isabel; Ginsberg, Silvia S.; Griep, Gilberto H.

2016-04-01

Acoustic anomalies in seismic records have revealed that gas-charged sediments are very common features in the coastal environments around the world. The ubiquitous gassy sediments challenge the effective acoustic mapping of shallow stratigraphy by seismic means, as well as having an important influence on environmental issues related to the coastal zone occupation and management. This paper documents examples of gassy sediments from coastal lagoons, estuaries, rivers, bays and the inner shelf and nearshore environments of Brazil, Argentina and South Africa. Seismic echograms from selected areas show several gas-related anomalies, which present distinctive morphologies for sediment-trapped gas, leaking or free gas discharge into the water column. In several places the gas-charged sediments occur in areas of palaeo-topographic lows related to fluvial channels and valleys that developed in the coastal zone due to sea level oscillations during the Quaternary period. This forcing by palaeo-topographic features results in the occurrence of shallow gas being controlled in most coastal sites by the previous environmental scenario, the stratigraphic arrangement of the transgressive infilling elements, and the local hydrodynamic conditions.

Assessment of ERTS-1 imagery as a tool for regional geological analysis in New York State. [Lake Ontario

NASA Technical Reports Server (NTRS)

Isachsen, Y. W. (Principal Investigator); Fakundiny, R. H.; Forster, S. W.

1974-01-01

The author has identified the following significant results. Linear anomalies dominate the new geological information derived from ERTS-1 imagery, total lengths now exceeding 26,500 km. Maxima on rose diagrams for ERTS-1 anomalies correspond well with those for mapped faults and topographic lineaments. Multi-scale analysis of linears shows that single topographic linears at 1:2,500,000 may become dashed linears at 1:1,000,000 aligned zones of shorter parallel, en echelon, or conjugate linears at 1:5000,000, and shorter linears lacking any conspicuous zonal alignment at 1:250,000. Field work in the Catskills suggests that the prominent new NNE lineaments may be surface manifestations of dip slip faulting in the basement, and that it may become possible to map major joint sets over extensive plateau regions directly on the imagery. Most circular features found were explained away by U-2 airfoto analysis but several remain as anomalies. Visible glacial features include individual drumlins, drumlinoids, eskers, ice-marginal drainage channels, glacial lake shorelines, sand plains, and end moraines.

Previously Unrecognized Large Lunar Impact Basins Revealed by Topographic Data

NASA Technical Reports Server (NTRS)

Frey, Herbert V.

2008-01-01

The discovery of a large population of apparently buried impact craters on Mars, revealed as Quasi- Circular Depressions (QCDs) in Mars Orbiting Laser Altimeter (MOLA) data [1,2,3] and as Circular Thin Areas (CTAs) [4] in crustal thickness model data [5] leads to the obvious question: are there unrecognized impact features on the Moon and other bodies in the solar system? Early analysis of Clementine topography revealed several large impact basins not previously known [6,7], so the answer certainly is "Yes." How large a population of previously undetected impact basins, their size frequency distribution, and how much these added craters and basins will change ideas about the early cratering history and Late Heavy Bombardment on the Moon remains to be determined. Lunar Orbiter Laser Altimeter (LOLA) data [8] will be able to address these issues. As a prelude, we searched the state-of-the-art global topographic grid for the Moon, the Unified Lunar Control Net (ULCN) [9] for evidence of large impact features not previously recognized by photogeologic mapping, as summarized by Wilhelms [lo].

Helium isotopes at Rungwe Volcanic Province, Tanzania, and the origin of East African Plateaux

NASA Astrophysics Data System (ADS)

Hilton, D. R.; Halldórsson, S. A.; Barry, P. H.; Fischer, T. P.; de Moor, J. M.; Ramirez, C. J.; Mangasini, F.; Scarsi, P.

2011-11-01

We report helium isotope ratios (3He/4He) of lavas and tephra of the Rungwe Volcanic Province (RVP) in southern Tanzania. Values as high as 15RA (RA = air 3He/4He) far exceed typical upper mantle values, and are the first observation of plume-like ratios south of the Turkana Depression which separates the topographic highs of the Ethiopia and Kenya domes. The African Superplume - a tilted low-velocity seismic anomaly extending to the core-mantle boundary beneath southern Africa - is the likely source of these high 3He/4He ratios. High 3He/4He ratios at RVP together with similarly-high values along the Main Ethiopian Rift and in Afar provide compelling evidence that the African Superplume is a feature that extends through the 670-km seismic discontinuity and provides dynamic support - either as a single plume or via multiple upwellings - for the two main topographic features of the East Africa Rift System as well as heat and mass to drive continuing rift-related magmatism.

Divergent evolution in fluviokarst landscapes of central Kentucky

USGS Publications Warehouse

Phillips, J.D.; Martin, L.L.; Nordberg, V.G.; Andrews, W.A.

2004-01-01

Central Kentucky is characterized by a mixture of karst and fluvial features, typically manifested as mosaic of karst-rich/ channel-poor (KRCP) and channel-rich/karst-poor (CRKP) environments. At the regional scale the location and distribution of KRCP and CRKP areas are not always systematically related to structural, lithological, topographic, or other controls. This study examines the relationship of KRCP and CRKP zones along the Kentucky River gorge area, where rapid incision in the last 1??5 million years has lowered local base levels and modified slopes on the edge of the inner bluegrass plateau. At the scale of detailed field mapping on foot within a 4 km2 area, the development of karst and fluvial features is controlled by highly localized structural and topographic constraints, and can be related to slope changes associated with retreat of the Kentucky River gorge escarpment. A conceptual model of karst/fluvial transitions is presented, which suggests that minor, localized variations are sufficient to trigger a karst-fluvial or fluvial-karst switch when critical slope thresholds are crossed. ?? 2004 John Wiley and Sons, Ltd.

Nature of the South Pole on Mars Determined by Topographic Forcing of Atmosphere Dynamics

NASA Technical Reports Server (NTRS)

Colaprete, A.; Barnes, Jeffrey R.; Haberle, Robert M.; Hollingsworth, Jeffery L.; Kieffer, Hugh H.; Titus, Timothy N.

2005-01-01

Introduction: The observed Springtime (Ls approx. 200) surface albedo in the Martian southern polar region is shown in Figure 1. In general, the hemisphere west of Hellas is marked by relatively high values of surface albedo. In contrast, the hemisphere east of Hellas contains extensive regions of very low surface albedo. One of the brightest features within the western hemisphere is the South Pole Residual Cap (SPRC). The dark region, which dominates the eastern hemisphere, is the "Cryptic" region[1]. The nature of the SPRC has been the source of considerable debate since its identification as CO2 ice by the Viking spacecraft. Two fundamental questions still exist regarding the SPRC s formation, location and stability. First, why is the SPRC offset from the geographic pole? There are no local topographic features or surface properties that can account for the offset in the SPRC. Second, does the SPRC represent a large or a small reservoir of CO2? If the former, then it could possibly buffer the surface pressure. If the latter, then the SPRC may not survive every year.

Titan's topography as a clue to geologic processes and landscape evolution

NASA Astrophysics Data System (ADS)

Kirk, R. L.

2012-12-01

Cassini has revealed a diversity of surface features on Titan rivaled by few bodies in the Solar System. Some of these features are readily identified: dunes, channels, lakes, seas, fresh impact craters, and mountains. Others are enigmatic and in some cases have sparked debate about their mode of origin. Given the limited resolution of the Cassini images, at best 300 m for synthetic aperture RADAR (SAR) images, it can be difficult to identify details that might confirm a particular mode of origin. Supplementing the images with topographic information provides an important and sometimes crucial clue to the origin and evolution of landforms. Topographic profiles from altimetry and SARTopo analysis of the images can shed light on simpler features (e.g., dunes) and led to the surprising conclusion that Titan's largest feature, Xanadu, is not elevated as had been supposed. For more complex structures, digital topographic models (DTMs) provide a full three-dimensional view. About 10% of Titan's surface has been imaged in stereo by RADAR, and we have produced DTMs of about 2% by analyzing these stereopairs. Analysis of the results within the Cassini RADAR team has shed light on a number of geologic problems: * Some putative volcanic features (e.g., the supposed dome Ganesa Macula and various diffuse surface flows) have been shown to lack the expected relief, greatly weakening the case for their volcanic origin. * Conversely, flows in Hotei Regio have been shown to tower over nearby fluvial channels, and those near Sotra Facula are associated with multiple edifices and caldera-like pits, strengthening the case for a volcanic origin. * Depths of the handful of definite impact craters measured so far range from Ganymede-like to nearly zero, and are statistically consistent with a process such as eolian deposition that would steadily reduce the crater depth rather than a process such as surface erosion that would tend to leave craters only partially filled. * Clustering of the small north-polar lakes at a few discrete levels, all of which are hundreds of meters above the major seas, suggests that these bodies of liquid are connected locally but not (over relevant timescales) regionally by subsurface flow. * Evidence for topographic "benches" at multiple levels around the seas suggests that the liquid level has fluctuated over time, perhaps as a result of inter-hemispheric transport of volatiles over multi-seasonal timescales. These examples come primarily from Titan's northern hemisphere and equatorial zone. Cassini's extended mission to date has yielded extensive coverage of the southern hemisphere that we have recently integrated into a global control network, allowing us to begin producing DTMs of multiple southern hemisphere sites with consistent absolute elevations. Of particular interest are apparent basins, for the most part empty of surface liquid, near the South Pole. Are the basin floors or possible shoreline features at consistent elevations? How do the depths and absolute elevations compare to Ontario Lacus and the other small lakes (including transient ones) in the south, and to the lakes and seas of the northern hemisphere? Topomapping now under way will help address these and other questions about the evolution of Titan's southern hemisphere and its volatile distribution over time.

Development and evaluation of a specialized task taxonomy for spatial planning - A map literacy experiment with topographic maps

NASA Astrophysics Data System (ADS)

Rautenbach, Victoria; Coetzee, Serena; Çöltekin, Arzu

2017-05-01

Topographic maps are among the most commonly used map types, however, their complex and information-rich designs depicting natural, human-made and cultural features make them difficult to read. Regardless of their complexity, spatial planners make extensive use of topographic maps in their work. On the other hand, various studies suggest that map literacy among the development planning professionals in South Africa is not very high. The widespread use of topographic maps combined with the low levels of map literacy presents challenges for effective development planning. In this paper we address some of these challenges by developing a specialized task taxonomy based on systematically assessed map literacy levels; and conducting an empirical experiment with topographic maps to evaluate our task taxonomy. In such empirical studies if non-realistic tasks are used, the results of map literacy tests may be skewed. Furthermore, experience and familiarity with the studied map type play a role in map literacy. There is thus a need to develop map literacy tests aimed at planners specifically. We developed a taxonomy of realistic map reading tasks typically executed during the planning process. The taxonomy defines six levels tasks of increasing difficulty and complexity, ranging from recognising symbols to extracting knowledge. We hypothesized that competence in the first four levels indicates functional map literacy. In this paper, we present results from an empirical experiment with 49 map literate participants solving a subset of tasks from the first four levels of the taxonomy with a topographic map. Our findings suggest that the proposed taxonomy is a good reference for evaluating topographic map literacy. Participants solved the tasks on all four levels as expected and we therefore conclude that the experiment based on the first four levels of the taxonomy successfully determined the functional map literacy of the participants. We plan to continue the study for the remaining levels, repeat the experiments with a group of map illiterate participants to confirm that the taxonomy can also be used to determine map illiteracy.

Evaluating some computer exhancement algorithms that improve the visibility of cometary morphology

NASA Technical Reports Server (NTRS)

Larson, Stephen M.; Slaughter, Charles D.

1992-01-01

Digital enhancement of cometary images is a necessary tool in studying cometary morphology. Many image processing algorithms, some developed specifically for comets, have been used to enhance the subtle, low contrast coma and tail features. We compare some of the most commonly used algorithms on two different images to evaluate their strong and weak points, and conclude that there currently exists no single 'ideal' algorithm, although the radial gradient spatial filter gives the best overall result. This comparison should aid users in selecting the best algorithm to enhance particular features of interest.

Pathologic features of early inflammatory bowel disease.

PubMed

Finkelstein, Sydney D; Sasatomi, Eizaburo; Regueiro, Miguel

2002-03-01

Often the pathologic changes of IBD are subtle and may not be present in a proportion of biopsy specimens. In cases of early disease, the changes may be missed, and additional specimens should be taken after a period of time. Modifying factors, such as prebiopsy treatment and coexisting disease, should be considered. A forum to review cases and allow for communication between gastroenterologists and pathologists is especially useful for clinicopathologic correlation and assignment of a working diagnosis to each case. Careful attention to the pathologic features of early UC and CD would be most useful when evaluating new therapies for IBD.

Comparison of Surface Flow Features from Lidar-Derived Digital Elevation Models with Historical Elevation and Hydrography Data for Minnehaha County, South Dakota

USGS Publications Warehouse

Poppenga, Sandra K.; Worstell, Bruce B.; Stoker, Jason M.; Greenlee, Susan K.

2009-01-01

The U.S. Geological Survey (USGS) has taken the lead in the creation of a valuable remote sensing product by incorporating digital elevation models (DEMs) derived from Light Detection and Ranging (lidar) into the National Elevation Dataset (NED), the elevation layer of 'The National Map'. High-resolution lidar-derived DEMs provide the accuracy needed to systematically quantify and fully integrate surface flow including flow direction, flow accumulation, sinks, slope, and a dense drainage network. In 2008, 1-meter resolution lidar data were acquired in Minnehaha County, South Dakota. The acquisition was a collaborative effort between Minnehaha County, the city of Sioux Falls, and the USGS Earth Resources Observation and Science (EROS) Center. With the newly acquired lidar data, USGS scientists generated high-resolution DEMs and surface flow features. This report compares lidar-derived surface flow features in Minnehaha County to 30- and 10-meter elevation data previously incorporated in the NED and ancillary hydrography datasets. Surface flow features generated from lidar-derived DEMs are consistently integrated with elevation and are important in understanding surface-water movement to better detect surface-water runoff, flood inundation, and erosion. Many topographic and hydrologic applications will benefit from the increased availability of accurate, high-quality, and high-resolution surface-water data. The remotely sensed data provide topographic information and data integration capabilities needed for meeting current and future human and environmental needs.

Nitrate and Moisture Content of Broad Permafrost Landscape Features in the Barrow Peninsula: Predicting Evolving NO3 Concentrations in a Changing Arctic

NASA Astrophysics Data System (ADS)

Arendt, C. A.; Heikoop, J. M.; Newman, B. D.; Wales, N. A.; McCaully, R. E.; Wilson, C. J.; Wullschleger, S.

2017-12-01

The geochemical evolution of Arctic regions as permafrost degrades, significantly impacts nutrient availability. The release of nitrogen compounds from permafrost degradation fertilizes both microbial decomposition and plant productivity. Arctic warming promotes permafrost degradation, causing geomorphic and hydrologic transitions that have the potential to convert saturated zones to unsaturated zones and subsequently alter the nitrate production capacity of permafrost regions. Changes in Nitrate (NO3-) content associated with shifting moisture regimes are a primary factor determining Arctic fertilization and subsequent primary productivity, and have direct feedbacks to carbon cycling. We have documented a broad survey of co-located soil moisture and nitrate concentration measurements in shallow active layer regions across a variety of topographic features in the expansive continuous permafrost region encompassing the Barrow Peninsula of Alaska. Topographic features of interest are slightly higher relative to surrounding landscapes with drier soils and elevated nitrate, including the rims of low centered polygons, the centers of flat and high centered polygons, the rims of young, old and ancient drain thaw lake basins and drainage slopes that exist across the landscape. With this information, we model the nitrate inventory of the Barrow Peninsula using multiple geospatial approaches to estimate total area cover by unsaturated features of interest and further predict how various drying scenarios increase the magnitude of nitrate produced in degrading permafrost regions across the Arctic. This work is supported by the US Department of Energy Next Generation Ecosystem Experiment, NGEE-Arctic.

Capabilities of current wildfire models when simulating topographical flow

NASA Astrophysics Data System (ADS)

Kochanski, A.; Jenkins, M.; Krueger, S. K.; McDermott, R.; Mell, W.

2009-12-01

Accurate predictions of the growth, spread and suppression of wild fires rely heavily on the correct prediction of the local wind conditions and the interactions between the fire and the local ambient airflow. Resolving local flows, often strongly affected by topographical features like hills, canyons and ridges, is a prerequisite for accurate simulation and prediction of fire behaviors. In this study, we present the results of high-resolution numerical simulations of the flow over a smooth hill, performed using (1) the NIST WFDS (WUI or Wildland-Urban-Interface version of the FDS or Fire Dynamic Simulator), and (2) the LES version of the NCAR Weather Research and Forecasting (WRF-LES) model. The WFDS model is in the initial stages of development for application to wind flow and fire spread over complex terrain. The focus of the talk is to assess how well simple topographical flow is represented by WRF-LES and the current version of WFDS. If sufficient progress has been made prior to the meeting then the importance of the discrepancies between the predicted and measured winds, in terms of simulated fire behavior, will be examined.

Topographic shear and the relation of ocular dominance columns to orientation columns in primate and cat visual cortex.

PubMed

Wood, Richard J.; Schwartz, Eric L.

1999-03-01

Shear has been known to exist for many years in the topographic structure of the primary visual cortex, but has received little attention in the modeling literature. Although the topographic map of V1 is largely conformal (i.e. zero shear), several groups have observed topographic shear in the region of the V1/V2 border. Furthermore, shear has also been revealed by anisotropy of cortical magnification factor within a single ocular dominance column. In the present paper, we make a functional hypothesis: the major axis of the topographic shear tensor provides cortical neurons with a preferred direction of orientation tuning. We demonstrate that isotropic neuronal summation of a sheared topographic map, in the presence of additional random shear, can provide the major features of cortical functional architecture with the ocular dominance column system acting as the principal source of the shear tensor. The major principal axis of the shear tensor determines the direction and its eigenvalues the relative strength of cortical orientation preference. This hypothesis is then shown to be qualitatively consistent with a variety of experimental results on cat and monkey orientation column properties obtained from optical recording and from other anatomical and physiological techniques. In addition, we show that a recent result of Das and Gilbert (Das, A., & Gilbert, C. D., 1997. Distortions of visuotopic map match orientation singularities in primary visual cortex. Nature, 387, 594-598) is consistent with an infinite set of parameterized solutions for the cortical map. We exploit this freedom to choose a particular instance of the Das-Gilbert solution set which is consistent with the full range of local spatial structure in V1. These results suggest that further relationships between ocular dominance columns, orientation columns, and local topography may be revealed by experimental testing.

Accuracy of topographic index models at identifying ephemeral gully trajectories on agricultural fields

NASA Astrophysics Data System (ADS)

Sheshukov, Aleksey Y.; Sekaluvu, Lawrence; Hutchinson, Stacy L.

2018-04-01

Topographic index (TI) models have been widely used to predict trajectories and initiation points of ephemeral gullies (EGs) in agricultural landscapes. Prediction of EGs strongly relies on the selected value of critical TI threshold, and the accuracy depends on topographic features, agricultural management, and datasets of observed EGs. This study statistically evaluated the predictions by TI models in two paired watersheds in Central Kansas that had different levels of structural disturbances due to implemented conservation practices. Four TI models with sole dependency on topographic factors of slope, contributing area, and planform curvature were used in this study. The observed EGs were obtained by field reconnaissance and through the process of hydrological reconditioning of digital elevation models (DEMs). The Kernel Density Estimation analysis was used to evaluate TI distribution within a 10-m buffer of the observed EG trajectories. The EG occurrence within catchments was analyzed using kappa statistics of the error matrix approach, while the lengths of predicted EGs were compared with the observed dataset using the Nash-Sutcliffe Efficiency (NSE) statistics. The TI frequency analysis produced bi-modal distribution of topographic indexes with the pixels within the EG trajectory having a higher peak. The graphs of kappa and NSE versus critical TI threshold showed similar profile for all four TI models and both watersheds with the maximum value representing the best comparison with the observed data. The Compound Topographic Index (CTI) model presented the overall best accuracy with NSE of 0.55 and kappa of 0.32. The statistics for the disturbed watershed showed higher best critical TI threshold values than for the undisturbed watershed. Structural conservation practices implemented in the disturbed watershed reduced ephemeral channels in headwater catchments, thus producing less variability in catchments with EGs. The variation in critical thresholds for all TI models suggested that TI models tend to predict EG occurrence and length over a range of thresholds rather than find a single best value.

Spatial recognition test: A novel cognition task for assessing topographical memory in mice.

PubMed

Havolli, Enes; Hill, Mark Dw; Godley, Annie; Goetghebeur, Pascal Jd

2017-06-01

Dysfunction in topographical memory is a core feature of several neurological disorders. There is a large unmet medical need to address learning and memory deficits as a whole in central nervous system disease. There are considerable efforts to identify pro-cognitive compounds but current methods are either lengthy or labour intensive. Our test used a two chamber apparatus and is based on the preference of rodents to explore novel environments. It was used firstly to assess topographical memory in mice at different retention intervals (RI) and secondly to investigate the effect of three drugs reported to be beneficial for cognitive decline associated with Alzheimer's disease, namely: donepezil, memantine and levetiracetam. Animals show good memory performance at all RIs tested under four hours. At the four-hour RI, animals show a significantly poorer memory performance which can be rescued using donepezil, memantine and levetiracetam. Using this test we established and validated a spatial recognition paradigm to address topographical memory in mice by showing a decremental time-induced forgetting response and reversing this decrease in performance using pharmacological tools. The spatial recognition test differs from more commonly used visuospatial laboratory tests in both throughput capability and potentially neuroanatomical substrate. This test has the potential to be used to assess cognitive performance in transgenic animals, disease models and to screen putative cognitive enhancers or depressors.

The importance of topographic corrections on magnetotelluric response data from rugged regions of Anatolia

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

Guerer, A.; Ilkisik, O.M.

1997-01-01

Topographic irregularities cause some distortions of magnetotelluric (MT) fields. In the vicinity of a topographic feature, the TM-mode distortion increases with the height and inclination of the slope. It is well-known that TM-mode topographic effects are much greater than TE-mode distortions. The authors have made a study of MT anomalies in TM-mode due to two-dimensional topography. In order to reduce these effects, the distortion tensor stripping technique was used. After corrections, the resulting data can be interpreted as if they were obtained over a flat surface and depend only on the subsurface structure. However, this technique sometimes causes some geometricalmore » distortions of the real subsurface structure. One of the aims is to overcome this failure. The authors have modified the correction coefficients by considering the actual one-dimensional geology. Model studies showed that this approach is especially useful in removing the terrain effects on complex 2D subsurface structures. The other purpose of this study is to emphasize the importance of a proper terrain correction for data from sites having mountainous topography over complex geology, e.g., strike-slip faults, suture zones and rift valleys. Some examples of MT data sets collected from the North Anatolian Fault Zone and from the thrust regions of the Western Taurides will be presented.« less

An Integrated Approach for the Large-Scale Simulation of Sedimentary Basins to Study Seismic Wave Amplification

NASA Astrophysics Data System (ADS)

Poursartip, B.

2015-12-01

Seismic hazard assessment to predict the behavior of infrastructures subjected to earthquake relies on ground motion numerical simulation because the analytical solution of seismic waves is limited to only a few simple geometries. Recent advances in numerical methods and computer architectures make it ever more practical to reliably and quickly obtain the near-surface response to seismic events. The key motivation stems from the need to access the performance of sensitive components of the civil infrastructure (nuclear power plants, bridges, lifelines, etc), when subjected to realistic scenarios of seismic events. We discuss an integrated approach that deploys best-practice tools for simulating seismic events in arbitrarily heterogeneous formations, while also accounting for topography. Specifically, we describe an explicit forward wave solver based on a hybrid formulation that couples a single-field formulation for the computational domain with an unsplit mixed-field formulation for Perfectly-Matched-Layers (PMLs and/or M-PMLs) used to limit the computational domain. Due to the material heterogeneity and the contrasting discretization needs it imposes, an adaptive time solver is adopted. We use a Runge-Kutta-Fehlberg time-marching scheme that adjusts optimally the time step such that the local truncation error rests below a predefined tolerance. We use spectral elements for spatial discretization, and the Domain Reduction Method in accordance with double couple method to allow for the efficient prescription of the input seismic motion. Of particular interest to this development is the study of the effects idealized topographic features have on the surface motion when compared against motion results that are based on a flat-surface assumption. We discuss the components of the integrated approach we followed, and report the results of parametric studies in two and three dimensions, for various idealized topographic features, which show motion amplification that depends, as expected, on the relation between the topographic feature's characteristics and the dominant wavelength. Lastly, we report results involving three-dimensional simulations.

Painting with Frost

NASA Image and Video Library

2016-12-07

Subtle variations in color look like brush strokes as the lightly frosted terrain reflects light. These variations provide a backdrop to some exotic features referred to colloquially as "spiders." The radial channels branching out from a central depression are formed when the seasonal layer of dry ice turns to gas in the spring and erodes the surface, which is a uniquely Martian landform. http://photojournal.jpl.nasa.gov/catalog/PIA21214

Use of the Primitive Unit Cell in Understanding Subtle Features of the Cubic Closest-Packed Structure

ERIC Educational Resources Information Center

Hawkins, John A.; Rittenhouse, Jeffrey L.; Soper, Linda M.; Rittenhouse, Robert C.

2008-01-01

One of the most important crystal structures adopted by metals is characterized by the "abcabc"...stacking of close-packed layers. This structure is commonly referred to in textbooks as the cubic close-packed (ccp) or face-centered cubic (fcc) structure, since the entire lattice can be generated by replication of a face-centered cubic unit cell…

Topographic precursors and geological structures of deep-seated catastrophic landslides caused by Typhoon Talas

NASA Astrophysics Data System (ADS)

Chigira, Masahiro; Tsou, Ching-Ying; Matsushi, Yuki; Hiraishi, Narumi; Matsuzawa, Makoto

2013-11-01

Typhoon Talas crossed the Japanese Islands between 2 and 5 September 2011, causing more than 70 deep-seated catastrophic landslides in a Jurassic to Paleogene-lower Miocene accretion complex. Detailed examination of the topographic features of 10 large landslides before the event, recorded on 1-m DEMs based on airborne laser scanner surveys, showed that all landslides had small scarps near their future crowns prior to the slide, and one landslide had linear depressions along its future crown as precursor topographic features. These scarps and linear depressions were caused by gravitational slope deformation that preceded the catastrophic failure. Although the scarps may have been enlarged by degradation, their sizes relative to the whole slopes suggest that minimal slope deformation had occurred in the period immediately before the catastrophic failure. The scarp ratio, defined as the ratio of length of a scarp to that of the whole slope both measured along the slope line, ranged from 5% to 21%. Careful examination of aerial photographs from another four large landslides, for which no high-resolution DEMs were available, suggested that they also developed scarps at their heads beforehand. Twelve of the 14 landslides we surveyed in the field had sliding surfaces with wedge-shaped discontinuities that consisted of faults and bedding, suggesting that the buildup of pore pressure occurs readily on wedge-shaped discontinuities in a gravitationally deformed rock body. Most of the faults were undulatory and were probably thrust faults that formed during accretion. Other types of gravitational deformation were also active; e.g., flexural toppling and buckling were observed to have preceded one landslide.

Large quasi-circular features beneath frost on Triton

NASA Technical Reports Server (NTRS)

Helfenstein, Paul; Veverka, Joseph; Mccarthy, Derek; Lee, Pascal; Hillier, John

1992-01-01

Specially processed Voyager 2 images of Neptune's largest moon, Triton, reveal three large quasi-circular features ranging in diameter from 280 to 935 km within Triton's equatorial region. The largest of these features contains a central irregularly shaped area of comparatively low albedo about 380 km in diameter, surrounded by crudely concentric annuli of higher albedo materials. None of the features exhibit significant topographic expression, and all appear to be primarily albedo markings. The features are located within a broad equatorial band of anomalously transparent frost that renders them nearly invisible at the large phase angles (alpha greater than 90 deg) at which Voyager obtained its highest resolution coverage of Triton. The features can be discerned at smaller phase angles (alpha = 66 deg) at which the frost only partially masks underlying albedo contrasts. The origin of the features is uncertain but may have involved regional cryovolcanic activity.

TBC1D24 mutation associated with focal epilepsy, cognitive impairment and a distinctive cerebro-cerebellar malformation.

PubMed

Afawi, Zaid; Mandelstam, Simone; Korczyn, Amos D; Kivity, Sara; Walid, Simri; Shalata, Adel; Oliver, Karen L; Corbett, Mark; Gecz, Jozef; Berkovic, Samuel F; Jackson, Graeme D

2013-07-01

We describe the clinical and radiological features of a family with a homozygous mutation in TBC1D24. The phenotype comprised onset of focal seizures at 2 months with prominent eye-blinking, facial and limb jerking with an oral sensory aura. These were controllable with medication but persisted into adult life. Associated features were mild to moderate intellectual disability and cerebellar features. MRI showed subtle cortical thickening with cerebellar atrophy and high signal confined to the ansiform lobule. The disorder is allelic with familial infantile myoclonic epilepsy, where intellect and neurologic examination are normal, highlighting the phenotypic variation with mutations of TBC1D24. Copyright © 2013 Elsevier B.V. All rights reserved.

Using UAV photogrammetry to study topographic change: application to Saskatchewan Glacier, Alberta, Canada

NASA Astrophysics Data System (ADS)

Meunier Cardinal, G.; Demuth, M. N.; Kinnard, C.

2016-12-01

Glaciers are an important source of fresh water in the headwaters of the Canadian Rocky Mountains, and ongoing climate warming could reduce their future hydrological contribution. Unmanned Aerial Vehicles UAVs) are an emergent technology that allow studying glacial processes with an unprecedented level of detail, but their usefulness for deriving accurate topographic data on glaciers has not yet been fully assessed. In this perspective we tested the use of a UAV platform to acquire images at a very high spatial resolution (<10cm) in order to estimate topographical and dynamic changes over a one year period on the ablation zone of Saskatchewan glacier, the main outlet of the Columbia Icefield in Alberta, Canada (52°06N, 117°15W). Two data acquisition campaigns were carried out, in August 2014 and 2015. Orthomosaics and digital elevation models (DEMs) with a high spatial resolution (<10cm) were produced for each year, using the Structure from Motion (SfM) algorithm. A detailed assessment of DEM errors was performed by cross-validation of an network of ground control points (GCPs) deployed on the glacier surface. The influence of checkpoint position in the network, border effects, number of photos calibrated and GPS accuracy were examined. Topographical changes were measured from the DEM difference and surface displacements estimated by applying feature tracking techniques to the orthomosaics. Further, the dominant scales of topographic spatial variability were examined using a semivariogram analysis of the DEMs. Results show that UAV-based photogrammetry is promising to further our understanding of high-resolution glacier surface processes and to perform repeat, on-demand monitoring of glacier changes, but their application on remote glaciers remains challenging.

Quantifying and Validating Rapid Floodplain Geomorphic Evolution, a Monitoring and Modelling Case Study

NASA Astrophysics Data System (ADS)

Scott, R.; Entwistle, N. S.

2017-12-01

Gravel bed rivers and their associated wider systems present an ideal subject for development and improvement of rapid monitoring tools, with features dynamic enough to evolve within relatively short-term timescales. For detecting and quantifying topographical evolution, UAV based remote sensing has manifested as a reliable, low cost, and accurate means of topographic data collection. Here we present some validated methodologies for detection of geomorphic change at resolutions down to 0.05 m, building on the work of Wheaton et al. (2009) and Milan et al. (2007), to generate mesh based and pointcloud comparison data to produce a reliable picture of topographic evolution. Results are presented for the River Glen, Northumberland, UK. Recent channel avulsion and floodplain interaction, resulting in damage to flood defence structures make this site a particularly suitable case for application of geomorphic change detection methods, with the UAV platform at its centre. We compare multi-temporal, high-resolution point clouds derived from SfM processing, cross referenced with aerial LiDAR data, over a 1.5 km reach of the watercourse. Changes detected included bank erosion, bar and splay deposition, vegetation stripping and incipient channel avulsion. Utilisation of the topographic data for numerical modelling, carried out using CAESAR-Lisflood predicted the avulsion of the main channel, resulting in erosion of and potentially complete circumvention of original channel and flood levees. A subsequent UAV survey highlighted topographic change and reconfiguration of the local sedimentary conveyor as we predicted with preliminary modelling. The combined monitoring and modelling approach has allowed probable future geomorphic configurations to be predicted permitting more informed implementation of channel and floodplain management strategies.

Patient-Specific Computational Modeling of Keratoconus Progression and Differential Responses to Collagen Cross-linking

PubMed Central

Sinha Roy, Abhijit

2011-01-01

Purpose. To model keratoconus (KC) progression and investigate the differential responses of central and eccentric cones to standard and alternative collagen cross-linking (CXL) patterns. Methods. Three-dimensional finite element models (FEMs) were generated with clinical tomography and IOP measurements. Graded reductions in regional corneal hyperelastic properties and thickness were imposed separately in the less affected eye of a KC patient. Topographic results, including maximum curvature and first-surface, higher-order aberrations (HOAs), were compared to those of the more affected contralateral eye. In two eyes with central and eccentric cones, a standard broad-beam CXL protocol was simulated with 200- and 300-μm treatment depths and compared to spatially graded broad-beam and cone-centered CXL simulations. Results. In a model of KC progression, maximum curvature and HOA increased as regional corneal hyperelastic properties were decreased. A topographic cone could be generated without a reduction in corneal thickness. Simulation of standard 9-mm-diameter CXL produced decreases in corneal curvature comparable to clinical reports and affected cone location. A 100-μm increase in CXL depth enhanced flattening by 24% to 34% and decreased HOA by 22% to 31%. Topographic effects were greatest with cone-centered CXL simulations. Conclusions. Progressive hyperelastic weakening of a cornea with subclinical KC produced topographic features of manifest KC. The clinical phenomenon of topographic flattening after CXL was replicated. The magnitude and higher-order optics of this response depended on IOP and the spatial distribution of stiffening relative to the cone location. Smaller diameter simulated treatments centered on the cone provided greater reductions in curvature and HOA than a standard broad-beam CXL pattern. PMID:22039252

Ultrastructural diversity between centrioles of eukaryotes.

PubMed

Gupta, Akshari; Kitagawa, Daiju

2018-02-16

Several decades of centriole research have revealed the beautiful symmetry present in these microtubule-based organelles, which are required to form centrosomes, cilia, and flagella in many eukaryotes. Centriole architecture is largely conserved across most organisms, however, individual centriolar features such as the central cartwheel or microtubule walls exhibit considerable variability when examined with finer resolution. Here, we review the ultrastructural characteristics of centrioles in commonly studied organisms, highlighting the subtle and not-so-subtle differences between specific structural components of these centrioles. Additionally, we survey some non-canonical centriole structures that have been discovered in various species, from the coaxial bicentrioles of protists and lower land plants to the giant irregular centrioles of the fungus gnat Sciara. Finally, we speculate on the functional significance of these differences between centrioles, and the contribution of individual structural elements such as the cartwheel or microtubules towards the stability of centrioles.Centriole structure, cartwheel, triplet microtubules, SAS-6, centrosome.

Coldspots and hotspots - Global tectonics and mantle dynamics of Venus

NASA Technical Reports Server (NTRS)

Bindschadler, Duane L.; Schubert, Gerald; Kaula, William M.

1992-01-01

Based on geologic observations provided by Magellan's first cycle of data collection and recent models of mantle convection in spherical shells and crustal deformation, the major topographic and geologic features of Venus are incorporated into a model of global mantle dynamics. Consideration is given to volcanic rises, such as Beta Regio and Atla Regio, plateau-shaped highlands dominated by complex ridged terrain (e.g., Ovda Regio and Alpha Regio), and circular lowland regions, such as Atalanta Planitia. Each of these features is related to either mantle plumes (hotspots) or mantle downwellings (coldspots).

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

Honorio, J.; Goldstein, R.; Honorio, J.

We propose a simple, well grounded classification technique which is suited for group classification on brain fMRI data sets that have high dimensionality, small number of subjects, high noise level, high subject variability, imperfect registration and capture subtle cognitive effects. We propose threshold-split region as a new feature selection method and majority voteas the classification technique. Our method does not require a predefined set of regions of interest. We use average acros ssessions, only one feature perexperimental condition, feature independence assumption, and simple classifiers. The seeming counter-intuitive approach of using a simple design is supported by signal processing and statisticalmore » theory. Experimental results in two block design data sets that capture brain function under distinct monetary rewards for cocaine addicted and control subjects, show that our method exhibits increased generalization accuracy compared to commonly used feature selection and classification techniques.« less

A detrimental soil disturbance prediction model for ground-based timber harvesting

Treesearch

Derrick A. Reeves; Matthew C. Reeves; Ann M. Abbott; Deborah S. Page-Dumroese; Mark D. Coleman

2012-01-01

Soil properties and forest productivity can be affected during ground-based harvest operations and site preparation. The degree of impact varies widely depending on topographic features and soil properties. Forest managers who understand site-specific limits to ground-based harvesting can alter harvest method or season to limit soil disturbance. To determine the...

The Hudson River Plume: Exploring Human Impact on the Coastal Environment

ERIC Educational Resources Information Center

McDonnell, Janice; Duncan, Ravit; Lichtenwalner, C. Sage; Dunbar, Laura

2010-01-01

The Hudson River Watershed contains a variety of geologic, topographic, climatic, and hydrologic features and a diversity of land-use patterns--making it an ideal model for studying human impact on the coastal environment. In this article, the authors present the Hudson River Plume (HRP), a problem-based online module that explores nonpoint-source…

Ecological and Topographic Features of Volcanic Ash-Influenced Forest Soils

Treesearch

Mark Kimsey; Brian Gardner; Alan Busacca

2007-01-01

Volcanic ash distribution and thickness were determined for a forested region of north-central Idaho. Mean ash thickness and multiple linear regression analyses were used to model the effect of environmental variables on ash thickness. Slope and slope curvature relationships with volcanic ash thickness varied on a local spatial scale across the study area. Ash...

Properties of pressure sensitive adhesives found in paper recycling operations

Treesearch

Ryan F. Verhulst; Steven J. Severtson; Jihui Guo; Carl J. Houtman

2006-01-01

Hot melt and water-based adhesives are very different materials with similar physical properties. Their ability to act as adhesives is due to physical bonds and mechanical interlocks which form as adhesive flows into topographical features on the substrate surface. Hot-melt adhesives are based on soft, rubbery polymers while water-based adhesives are usually acrylic...

A System for Drawing Synthetic Images of Forested Landscapes

Treesearch

Timothy P. McDonald

1997-01-01

A software package for drawing images of forested landscapes was developed. Programs included in the system convert topographic and stand polygon information output from a GIS into a form that can be read by a general-purpose ray-tracing renderer. Other programs generate definitions for surface features, mainly trees but ground surface textural properties as well. The...

Functional Analysis and Treatment of Arranging and Ordering by Individuals with an Autism Spectrum Disorder

ERIC Educational Resources Information Center

Rodriguez, Nicole M.; Thompson, Rachel H.; Schlichenmeyer, Kevin; Stocco, Corey S.

2012-01-01

Of the diagnostic features of autism, relatively little research has been devoted to restricted and repetitive behavior, particularly topographically complex forms of restricted and repetitive behavior such as rigidity in routines or compulsive-like behavior (e.g., arranging objects in patterns or rows). Like vocal or motor stereotypy,…

Martian North Polar Impacts and Volcanoes: Feature Discrimination and Comparisons to Global Trends

NASA Technical Reports Server (NTRS)

Sakimoto, E. H.; Weren, S. L.

2003-01-01

The recent Mars Global Surveyor and Mars Odyssey Missions have greatly improved our available data for the north polar region of Mars. Pre- MGS and MO studies proposed possible volcanic features, and have revealed numerous volcanoes and impact craters in a range of weathering states that were poorly visible or not visible in prior data sets. This new data has helped in the reassessment of the polar deposits. From images or shaded Mars Orbiter Laser Altimeter (MOLA) topography grids alone, it has proved to be difficult to differentiate cratered cones of probable volcanic origins from impact craters that appear to have been filled. It is important that the distinction is made if possible, as the relative ages of the polar deposits hinge on small numbers of craters, and the local volcanic regime originally only proposed small numbers of volcanoes. Therefore, we have expanded prior work on detailed topographic parameter measurements and modeling for the polar volcanic landforms and mapped and measured all of the probable volcanic and impact features for the north polar region as well as other midlatitude fields, and suggest that: 1) The polar volcanic edifices are significantly different topographically from midlatitude edifices, and have steeper slopes and larger craters as a group; 2) The impact craters are actually distinct from the volcanoes in terms of the feature volume that is cavity compared to feature volume that is positive relief; 3) There are actually several distinct types of volcanic edifices present; 4) These types tend to be spatially grouped by edifice. This is a contrast to many of the other small volcanic fields around Mars, where small edifices tend to be mixed types within a field.

Oxygen Plasma Modification of Poss-Coated Kapton(Registered TradeMark) HN Films

NASA Technical Reports Server (NTRS)

Wohl, C. J.; Belcher, M. A.; Ghose, S.; Connell, J. W.

2008-01-01

The surface energy of a material depends on both surface composition and topographic features. In an effort to modify the surface topography of Kapton(Registered TradeMark) HN film, organic solutions of a polyhedral oligomeric silsesquioxane, octakis(dimethylsilyloxy)silsesquioxane (POSS), were spray-coated onto the Kapton(Registered TradeMark) HN surface. Prior to POSS application, the Kapton(Registered TradeMark) HN film was activated by exposure to radio frequency (RF)-generated oxygen plasma. After POSS deposition and solvent evaporation, the films were exposed to various durations of RF-generated oxygen plasma to create a topographically rich surface. The modified films were characterized using optical microscopy, attenuated total reflection infrared (ATR-IR) spectroscopy, and high-resolution scanning electron microscopy (HRSEM). The physical properties of the modified films will be presented.

The response of stationary planetary waves to tropospheric forcing

NASA Technical Reports Server (NTRS)

Alpert, J. C.; Geller, M. A.; Avery, S. K.

1983-01-01

The lower boundary forcing of airflow over topography, and the internal forcing that results from the geographical distribution of diabatic heating, are studied in light of a steady state, linear, quasi-geostrophic model of stationary waves on a sphere. The lower boundary vertical motions forced by airflow over topography depend on whether the horizontal deflection of airflow around topographic features is taken into account, the level of the wind profile at which flow over topography is assumed to take place, and the topographic data set that was used in the forcing formulation. The lower boundary forcing is taken to be given by the observed stationary planetary wave in lower boundary geopotential height, and the internal forcing is computed using the planetary wave propagation equation on the observed wave structure.

Facial anatomy.

PubMed

Marur, Tania; Tuna, Yakup; Demirci, Selman

2014-01-01

Dermatologic problems of the face affect both function and aesthetics, which are based on complex anatomical features. Treating dermatologic problems while preserving the aesthetics and functions of the face requires knowledge of normal anatomy. When performing successfully invasive procedures of the face, it is essential to understand its underlying topographic anatomy. This chapter presents the anatomy of the facial musculature and neurovascular structures in a systematic way with some clinically important aspects. We describe the attachments of the mimetic and masticatory muscles and emphasize their functions and nerve supply. We highlight clinically relevant facial topographic anatomy by explaining the course and location of the sensory and motor nerves of the face and facial vasculature with their relations. Additionally, this chapter reviews the recent nomenclature of the branching pattern of the facial artery. © 2013 Elsevier Inc. All rights reserved.

Unique topographic distribution of greyhound nonsuppurative meningoencephalitis.

PubMed

Terzo, Eloisa; McConnell, J Fraser; Shiel, Robert E; McAllister, Hester; Behr, Sebastien; Priestnall, Simon L; Smith, Ken C; Nolan, Catherine M; Callanan, John J

2012-01-01

Greyhound nonsuppurative meningoencephalitis is an idiopathic breed-associated fatal meningoencephalitis with lesions usually occurring within the rostral cerebrum. This disorder can only be confirmed by postmortem examination, with a diagnosis based upon the unique topography of inflammatory lesions. Our purpose was to describe the magnetic resonance (MR) imaging features of this disease. Four Greyhounds with confirmed Greyhound nonsuppurative meningoencephalitis were evaluated by MR imaging. Lesions predominantly affected the olfactory lobes and bulbs, frontal, and frontotemporal cortical gray matter, and caudate nuclei bilaterally. Fluid attenuation inversion recovery (FLAIR) and T2 weighted spin-echo (T2W) sequences were most useful to assess the nature, severity, extension, and topographic pattern of lesions. Lesions were predominantly T2-hyperintense and T1-isointense with minimal or absent contrast enhancement. © 2012 Veterinary Radiology & Ultrasound.

Topographic mapping--the olfactory system.

PubMed

Imai, Takeshi; Sakano, Hitoshi; Vosshall, Leslie B

2010-08-01

Sensory systems must map accurate representations of the external world in the brain. Although the physical senses of touch and vision build topographic representations of the spatial coordinates of the body and the field of view, the chemical sense of olfaction maps discontinuous features of chemical space, comprising an extremely large number of possible odor stimuli. In both mammals and insects, olfactory circuits are wired according to the convergence of axons from sensory neurons expressing the same odorant receptor. Synapses are organized into distinctive spherical neuropils--the olfactory glomeruli--that connect sensory input with output neurons and local modulatory interneurons. Although there is a strong conservation of form in the olfactory maps of mammals and insects, they arise using divergent mechanisms. Olfactory glomeruli provide a unique solution to the problem of mapping discontinuous chemical space onto the brain.

Ceres Topographic Globe Animation

NASA Image and Video Library

2015-07-28

This frame from an animation shows a color-coded map from NASA Dawn mission revealing the highs and lows of topography on the surface of dwarf planet Ceres. The color scale extends 3.7 miles (6 kilometers) below the surface in purple to 3.7 miles (6 kilometers) above the surface in brown. The brightest features (those appearing nearly white) -- including the well-known bright spots within a crater in the northern hemisphere -- are simply reflective areas, and do not represent elevation. The topographic map was constructed from analyzing images from Dawn's framing camera taken from varying sun and viewing angles. The map was combined with an image mosaic of Ceres and projected onto a 3-D shape model of the dwarf planet to create the animation. http://photojournal.jpl.nasa.gov/catalog/PIA19605

Application of Generative Topographic Mapping to Gear Failures Monitoring

NASA Astrophysics Data System (ADS)

Liao, Guanglan; Li, Weihua; Shi, Tielin; Rao, Raj B. K. N.

2002-07-01

The Generative Topographic Mapping (GTM) model is introduced as a probabilistic re-formation of the self-organizing map and has already been used in a variety of applications. This paper presents a study of the GTM in industrial gear failures monitoring. Vibration signals are analyzed using the GTM model, and the results show that gear feature data sets can be projected into a two-dimensional space and clustered in different areas according to their conditions, which can classify and identify clearly a gear work condition with cracked or broken tooth compared with the normal condition. With the trace of the image points in the two-dimensional space, the variation of gear work conditions can be observed visually, therefore, the occurrence and varying trend of gear failures can be monitored in time.

Gravity study of the Pitcairn-Easter hotline

NASA Astrophysics Data System (ADS)

Maia, M.; Dehghani, G. A.; Diament, M.; Francheteau, J.; Stoffers, P.

1994-11-01

Shipboard free air gravity and bathymetric anomalies with an extension of 400 km were identified across the Pitcairn-Easter hotline in the South Pacific. The anomalies are associated with one of the positive geoid undulations observed in the area from satellite data. Several smaller topographic features, volcano-tectonic ridges oriented N 65 deg E, are superimposed on the topographic hig. Admittance computations and direct modeling show that the swell topography is compensated by a low density zone within the lithosphere, 4 to 8 km below the crust. The volcano tectonic ridges are locally compensated in a classical Airy sense. The swell and the associated ridges were probably created by the action of a thermal anomaly resulting from the interaction of the Easter Island hotspot and of the Easter Microplate accretion centers.

Airflows and turbulent flux measurements in mountainous terrain: Part 1. Canopy and local effects

USGS Publications Warehouse

Turnipseed, Andrew A.; Anderson, Dean E.; Blanken, Peter D.; Baugh, William M.; Monson, Russell K.

2003-01-01

We have studied the effects of local topography and canopy structure on turbulent flux measurements at a site located in mountainous terrain within a subalpine, coniferous forest. Our primary aim was to determine whether the complex terrain of the site affects the accuracy of eddy flux measurements from a practical perspective. We observed displacement heights, roughness lengths, spectral peaks, turbulent length scales, and profiles of turbulent intensities that were comparable in magnitude and pattern to those reported for forest canopies in simpler terrain. We conclude that in many of these statistical measures, the local canopy exerts considerably more influence than does topographical complexity. Lack of vertical flux divergence and modeling suggests that the flux footprints for the site are within the standards acceptable for the application of flux statistics. We investigated three different methods of coordinate rotation: double rotation (DR), triple rotation (TR), and planar-fit rotation (PF). Significant variability in rotation angles at low wind speeds was encountered with the commonly used DR and TR methods, as opposed to the PF method, causing some overestimation of the fluxes. However, these differences in fluxes were small when applied to large datasets involving sensible heat and CO2 fluxes. We observed evidence of frequent drainage flows near the ground during stable, stratified conditions at night. Concurrent with the appearance of these flows, we observed a positive bias in the mean vertical wind speed, presumably due to subtle topographic variations inducing a flow convergence below the measurement sensors. In the presence of such drainage flows, advection of scalars and non-zero bias in the mean vertical wind speed can complicate closure of the mass conservation budget at the site.

Surface topography characterization of brass alloys: lead brass (CuZn39Pb3) and lead free brass (CuZn21Si3P)

NASA Astrophysics Data System (ADS)

Reddy, Vijeth V.; Vedantha Krishna, Amogh; Schultheiss, Fredrik; Rosén, B.-G.

2017-06-01

Manufactured surfaces usually consist of topographical features which include both those put forth by the manufacturing process, and micro-features caused by disturbances during this process. Surface characterization basically involves study of these features which influence the functionality of the surface. This article focuses on characterization of the surface topography of machined lead brass and lead free brass. The adverse effect of lead on human health and the environment has led the manufacturing sector to focus on sustainable manufacturing of lead free brass, as well as how to maintain control of the surface integrity when substituting the lead content in the brass with silicon. The investigation includes defined areal surface parameters measured on the turned samples of lead- and lead free brass using an optical coherence scanning interferometer, CSI. This paper deals with the study of surface topography of turned samples of lead- and lead free brass. It is important to study the topographical characteristics of the brass samples which are the intermediate link between the manufacturing process variables and the functional behaviour of the surface. To numerically evaluate the sample’s surface topography and to validate the measurements for a significant study, a general statistical methodology is implemented. The results indicate higher surface roughness in turned samples of lead brass compared to lead free brass.

UAS-SfM for coastal research: Geomorphic feature extraction and land cover classification from high-resolution elevation and optical imagery

USGS Publications Warehouse

Sturdivant, Emily; Lentz, Erika; Thieler, E. Robert; Farris, Amy; Weber, Kathryn; Remsen, David P.; Miner, Simon; Henderson, Rachel

2017-01-01

The vulnerability of coastal systems to hazards such as storms and sea-level rise is typically characterized using a combination of ground and manned airborne systems that have limited spatial or temporal scales. Structure-from-motion (SfM) photogrammetry applied to imagery acquired by unmanned aerial systems (UAS) offers a rapid and inexpensive means to produce high-resolution topographic and visual reflectance datasets that rival existing lidar and imagery standards. Here, we use SfM to produce an elevation point cloud, an orthomosaic, and a digital elevation model (DEM) from data collected by UAS at a beach and wetland site in Massachusetts, USA. We apply existing methods to (a) determine the position of shorelines and foredunes using a feature extraction routine developed for lidar point clouds and (b) map land cover from the rasterized surfaces using a supervised classification routine. In both analyses, we experimentally vary the input datasets to understand the benefits and limitations of UAS-SfM for coastal vulnerability assessment. We find that (a) geomorphic features are extracted from the SfM point cloud with near-continuous coverage and sub-meter precision, better than was possible from a recent lidar dataset covering the same area; and (b) land cover classification is greatly improved by including topographic data with visual reflectance, but changes to resolution (when <50 cm) have little influence on the classification accuracy.

The Rest of the C2 Iceberg

DTIC Science & Technology

2014-08-01

Iceberg Feature ones—another documented cognitive bias that is largely subconscious . A final opportunity lost by not having a forward geographic presence...leading to a subtle bias towards the tip-of-the-iceberg systems that most individuals have more famil- iarity with from their tactical backgrounds...as soon as possible to maintain career viability in a system biased more towards tactical achievement. Acknowledge That the Heart of Operational C2 Is

Mining and Querying Multimedia Data

DTIC Science & Technology

2011-09-29

able to capture more subtle spatial variations such as repetitiveness. Local feature descriptors such as SIFT [74] and SURF [12] have also been widely...empirically set to s = 90%, r = 50%, K = 20, where small variations lead to little perturbation of the output. The pseudo-code of the algorithm is...by constructing a three-layer graph based on clustering outputs, and executing a slight variation of random walk with restart algorithm. It provided

Characterization of 24-h cortisol release in obese and non-obese hyperandrogenic women.

PubMed

Miller, J E; Bray, M A; Faiman, C; Reyes, F I

1994-12-01

Excessive androgen output is a well-recognized feature of adrenocortical oversecretion in women with ovarian hyperandrogenism, or polycystic ovary disease (PCOD). However, evidence of a concomitant alteration of cortisol secretion is lacking even though obesity per se, a common clinical feature of PCOD, has been shown to be associated with cortisol oversecretion. To clarify whether a subtle alteration in cortisol secretion exists, a study of 24-h episodic cortisol release and post-prandial cortisol responses was undertaken in eight women with PCOD and eight normal women comprising equal numbers of obese and non-obese subjects. All four groups showed normal biphasic 24-h cortisol secretion profiles but cortisol pulse frequency was increased in the PCOD groups. Independently, both hyperandrogenism and obesity were associated with an accelerated cortisol clearance rate. These changes, together with normal or only slightly elevated 24-h cortisol integrated area under the curve, suggest an increased compensatory cortisol production in women with PCOD. Furthermore, subjects with PCOD and subjects with obesity showed different post-prandial cortisol responses to normal non-obese women. In conclusion, these subtle cortisol abnormalities may be a manifestation of altered central regulation of the hypothalamic-pituitary-adrenal axis and peripheral metabolic abnormalities, and may be linked to the pathophysiology of PCOD.

An analysis-by-synthesis approach to the estimation of vocal cord polyp features.

PubMed

Koizumi, T; Taniguchi, S; Itakura, F

1993-09-01

This paper deals with a new noninvasive method of estimating vocal cord polyp features through hoarse-voice analysis. A noteworthy feature of this method is that it enables us not only to discriminate hoarse voices caused by pathological vocal cords with a single golf-ball-like polyp from normal voices, but also to estimate polyp features such as the mass and dimension of polyp through the use of a novel model of pathological vocal cords which has been devised to simulate the subtle movement of the vocal cords. A synthetic hoarse voice produced with a hoarse-voice synthesizer is compared with a natural hoarse voice caused by the vocal cord polyp in terms of a distance measure and the polyp features are estimated by minimizing the distance measure. Some estimates of polyp dimension that have been obtained by applying this procedure to hoarse voices are found to compare favorably with actual polyp dimensions, demonstrating that the procedure is effective for estimating the features of golf-ball-like vocal cord polyps.

Shaded Relief with Height as Color and Landsat, Yucatan Peninsula, Mexico

NASA Technical Reports Server (NTRS)

2003-01-01

The top picture is a shaded relief image of the northwest corner of Mexico's Yucatan Peninsula generated from Shuttle Radar Topography Mission (SRTM) data, and shows a subtle, but unmistakable, indication of the Chicxulub impact crater. Most scientists now agree that this impact was the cause of the Cretatious-Tertiary Extinction, the event 65 million years ago that marked the sudden extinction of the dinosaurs as well as the majority of life on Earth. The pattern of the crater's rim is marked by a trough, the darker green semicircular line near the center of the picture. This trough is only about 3 to 5 meters (10 - 15 feet) deep and is about 5 km (3 miles) wide; so subtle that if you walked across it you probably would not notice it. It is the surface expression of the buried crater's outer boundary. Scientists believe the impact, which was centered just off the coast in the Caribbean, altered the subsurface rocks such that the overlying limestone sediments, which formed later and erode very easily, would preferentially erode along the crater rim. This formed the trough as well as numerous sinkholes (called cenotes) which are visible as small circular depressions.

The bottom picture is the same area viewed by the Landsat satellite, and was made by displaying the Thematic Mapper's Band 7 (mid-infrared), Band 4 (near-infrared) and Band 2 (green) as red, green and blue. These colors were chosen to maximize the contrast between different vegetation and land cover types, with native vegetation and cultivated land showing as green, yellow and magenta, and urban areas as white. The circular white area near the center of the image is Merida, a city of about 720,000 population. Notice that in the SRTM image, which shows only topography, the city is not visible, while in the Landsat image, which does not show elevations, the trough is not visible.

Two visualization methods were combined to produce the SRTM image: shading and color coding of topographic height. The shade image was derived by computing topographic slope in the northwest-southeast direction, so that northwest slopes appear bright and southeast slopes appear dark. Color coding is directly related to topographic height, with green at the lower elevations, rising through yellow and tan, to white at the highest elevations.

Elevation data used in this image were acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect 3-D measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter (approximately 200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between NASA, the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Earth Science Enterprise, Washington, D.C.

Size: 261 by 162 kilometers (162 by 100 miles) Location: 20.8 degrees North latitude, 89.3 degrees West longitude Orientation: North toward the top, Mercator projection Image Data: shaded and colored SRTM elevation model Original Data Resolution: SRTM 1 arcsecond (about 30 meters or 98 feet) Date Acquired: February 2000

Shaded Relief with Height as Color, Yucatan Peninsula, Mexico

NASA Technical Reports Server (NTRS)

2003-01-01

This shaded relief image of Mexico's Yucatan Peninsula show a subtle, but unmistakable, indication of the Chicxulub impact crater. Most scientists now agree that this impact was the cause of the Cretatious-Tertiary Extinction, the event 65 million years ago that marked the sudden extinction of the dinosaurs as well as the majority of life then on Earth.

Most of the peninsula is visible here, along with the island of Cozumel off the east coast. The Yucatan is a plateau composed mostly of limestone and is an area of very low relief with elevations varying by less than a few hundred meters (about 500 feet.) In this computer-enhanced image the topography has been greatly exaggerated to highlight a semicircular trough, the darker green arcing line at the upper left corner of the peninsula. This trough is only about 3 to 5 meters (10 to 15 feet) deep and is about 5 km. wide (3 miles), so subtle that if you walked across it you probably would not notice it, and is a surface expression of the crater's outer boundary. Scientists believe the impact, which was centered just off the coast in the Caribbean, altered the subsurface rocks such that the overlying limestone sediments, which formed later and erode very easily, would preferentially erode on the vicinity of the crater rim. This formed the trough as well as numerous sinkholes (called cenotes) which are visible as small circular depressions.

Two visualization methods were combined to produce the image: shading and color coding of topographic height. The shade image was derived by computing topographic slope in the northwest-southeast direction, so that northwestern slopes appear bright and southeastern slopes appear dark. Color coding is directly related to topographic height, with green at the lower elevations, rising through yellow and tan, to white at the highest elevations.

For a smaller, annotated version of this image, please select Figure 1, below: [figure removed for brevity, see original site] (Large image: 1.5 mB jpeg)

Elevation data used in this image were acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect 3-D measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter (approximately 200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between NASA, the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Earth Science Enterprise, Washington, D.C.

Size: 261 by 162 kilometers (162 by 100 miles) Location: 20.8 degrees North latitude, 89.3 degrees West longitude Orientation: North toward the top, Mercator projection Image Data: shaded and colored SRTM elevation model Original Data Resolution: SRTM 1 arcsecond (about 30 meters or 98 feet) Date Acquired: February 2000

Hidden flexion injury of the cervical spine.

PubMed

Webb, J K; Broughton, R B; McSweeney, T; Park, W M

1976-08-01

This paper describes seven patients who developed late vertebral deformity after flexion injuries of the cervical spine. In four the clinical and radiological features were subtle and because the patients walked into an emergency department the severity of the injury was not initially appreciated. Certain specific clinical and radiological features of flexion injury are described and emphasis is placed on the importance of correct management. A radiological tetrad is described which should alert the surgeon to the possibility of damage to the posterior interspinous complex of the cervical spine and so lead to further radiological investigations. Despite the frequency of flexion injuries the alarming complications described in this paper are rare.

Drainage and Landscape Evolution in the Bighorn Basin Accompanying Advection of the Yellowstone Hotspot Swell Through North America

NASA Astrophysics Data System (ADS)

Guerrero, E. F.; Meigs, A.

2012-12-01

Mantle plumes have been recognized to express themselves on the surface as long wavelength and low amplitude topographic swells. These swells are measured as positive geoid anomalies and include shorter wavelength topographic features such as volcanic edifices and pre-exisitng topography. Advection of the topographic swell is expected as the lithosphere passes over the plume uplift source. The hot spot swell occurs in the landscape as transient signal that is expressed with waxing and waning topography. Waxing topography occurs at the leading edge of the swell and is expressed as an increase in rock uplift that is preserved by rivers and landscapes. Advection of topography predicts a shift in a basin from deposition to incision, an increase in convexity of a transverse river's long profile and a lateral river migration in the direction of advection. The Yellowstone region has a strong positive geoid anomaly and the volcanic signal, which have been interpreted as the longer and shorter wavelength topographic expressions of the hot spot. These expressions of the hot spot developed in a part of North America with a compounded deformation and topographic history. Previous studies of the Yellowstone topographic swell have concentrated on the waning or trailing signal preserved in the Snake River Plain. Our project revisits the classic geomorphology study area in the Bighorn Basin of Wyoming and Montana, which is in leading edge of the swell. Present models identify the swell as having a 400 km in diameter and that it is centered on the Yellowstone caldera. If we assume advection to occur in concert with the caldera eruptive track, the Yellowstone swell has migrated to the northeast at a rate of 3 cm yr-1 and began acting on the Bighorn Basin's landscape between 3 and 2 Ma. The Bighorn Basin has an established history of a basin-wide switch from deposition to incision during the late Pliocene, yet the age control on the erosional evolution of the region is relative. This basin is an ideal location to quantify long wavelength dynamic topography due to its low relief. Long river profiles streams that are transverse to the topographic swell in the basin suggest a transient advective signal preserved as profile knickpoints. Abandoned strath terraces, stream piracy, drainage reorganization, and lateral channel migration within the Bighorn Basin are all consistent indicators of the advection of a topographic swell. However, the lack of a high-resolution absolute age chronology precludes us from attributing the primary landscape and drainage forcing to climate change or dynamic topography. Our future work will focus on the timing of geomorphic and river profile evolution to disentangle competing effects of topographic advection, climate, and other factors.

Multivariate pattern analysis reveals subtle brain anomalies relevant to the cognitive phenotype in neurofibromatosis type 1.

PubMed

Duarte, João V; Ribeiro, Maria J; Violante, Inês R; Cunha, Gil; Silva, Eduardo; Castelo-Branco, Miguel

2014-01-01

Neurofibromatosis Type 1 (NF1) is a common genetic condition associated with cognitive dysfunction. However, the pathophysiology of the NF1 cognitive deficits is not well understood. Abnormal brain structure, including increased total brain volume, white matter (WM) and grey matter (GM) abnormalities have been reported in the NF1 brain. These previous studies employed univariate model-driven methods preventing detection of subtle and spatially distributed differences in brain anatomy. Multivariate pattern analysis allows the combination of information from multiple spatial locations yielding a discriminative power beyond that of single voxels. Here we investigated for the first time subtle anomalies in the NF1 brain, using a multivariate data-driven classification approach. We used support vector machines (SVM) to classify whole-brain GM and WM segments of structural T1 -weighted MRI scans from 39 participants with NF1 and 60 non-affected individuals, divided in children/adolescents and adults groups. We also employed voxel-based morphometry (VBM) as a univariate gold standard to study brain structural differences. SVM classifiers correctly classified 94% of cases (sensitivity 92%; specificity 96%) revealing the existence of brain structural anomalies that discriminate NF1 individuals from controls. Accordingly, VBM analysis revealed structural differences in agreement with the SVM weight maps representing the most relevant brain regions for group discrimination. These included the hippocampus, basal ganglia, thalamus, and visual cortex. This multivariate data-driven analysis thus identified subtle anomalies in brain structure in the absence of visible pathology. Our results provide further insight into the neuroanatomical correlates of known features of the cognitive phenotype of NF1. Copyright © 2012 Wiley Periodicals, Inc.

Erosion and Channel Incision Analysis with High-Resolution Lidar

NASA Astrophysics Data System (ADS)

Potapenko, J.; Bookhagen, B.

2013-12-01

High-resolution LiDAR (LIght Detection And Ranging) provides a new generation of sub-meter topographic data that is still to be fully exploited by the Earth science communities. We make use of multi-temporal airborne and terrestrial lidar scans in the south-central California and Santa Barbara area. Specifically, we have investigated the Mission Canyon and Channel Islands regions from 2009-2011 to study changes in erosion and channel incision on the landscape. In addition to gridding the lidar data into digital elevation models (DEMs), we also make use of raw lidar point clouds and triangulated irregular networks (TINs) for detailed analysis of heterogeneously spaced topographic data. Using recent advancements in lidar point cloud processing from information technology disciplines, we have employed novel lidar point cloud processing and feature detection algorithms to automate the detection of deeply incised channels and gullies, vegetation, and other derived metrics (e.g. estimates of eroded volume). Our analysis compares topographically-derived erosion volumes to field-derived cosmogenic radionuclide age and in-situ sediment-flux measurements. First results indicate that gully erosion accounts for up to 60% of the sediment volume removed from the Mission Canyon region. Furthermore, we observe that gully erosion and upstream arroyo propagation accelerated after fires, especially in regions where vegetation was heavily burned. The use of high-resolution lidar point cloud data for topographic analysis is still a novel method that needs more precedent and we hope to provide a cogent example of this approach with our research.

Surface topography during neural stem cell differentiation regulates cell migration and cell morphology.

PubMed

Czeisler, Catherine; Short, Aaron; Nelson, Tyler; Gygli, Patrick; Ortiz, Cristina; Catacutan, Fay Patsy; Stocker, Ben; Cronin, James; Lannutti, John; Winter, Jessica; Otero, José Javier

2016-12-01

We sought to determine the contribution of scaffold topography to the migration and morphology of neural stem cells by mimicking anatomical features of scaffolds found in vivo. We mimicked two types of central nervous system scaffolds encountered by neural stem cells during development in vitro by constructing different diameter electrospun polycaprolactone (PCL) fiber mats, a substrate that we have shown to be topographically similar to brain scaffolds. We compared the effects of large fibers (made to mimic blood vessel topography) with those of small-diameter fibers (made to mimic radial glial process topography) on the migration and differentiation of neural stem cells. Neural stem cells showed differential migratory and morphological reactions with laminin in different topographical contexts. We demonstrate, for the first time, that neural stem cell biological responses to laminin are dependent on topographical context. Large-fiber topography without laminin prevented cell migration, which was partially reversed by treatment with rock inhibitor. Cell morphology complexity assayed by fractal dimension was inhibited in nocodazole- and cytochalasin-D-treated neural precursor cells in large-fiber topography, but was not changed in small-fiber topography with these inhibitors. These data indicate that cell morphology has different requirements on cytoskeletal proteins dependent on the topographical environment encountered by the cell. We propose that the physical structure of distinct scaffolds induces unique signaling cascades that regulate migration and morphology in embryonic neural precursor cells. J. Comp. Neurol. 524:3485-3502, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

FILMPAR: A parallel algorithm designed for the efficient and accurate computation of thin film flow on functional surfaces containing micro-structure

NASA Astrophysics Data System (ADS)

Lee, Y. C.; Thompson, H. M.; Gaskell, P. H.

2009-12-01

FILMPAR is a highly efficient and portable parallel multigrid algorithm for solving a discretised form of the lubrication approximation to three-dimensional, gravity-driven, continuous thin film free-surface flow over substrates containing micro-scale topography. While generally applicable to problems involving heterogeneous and distributed features, for illustrative purposes the algorithm is benchmarked on a distributed memory IBM BlueGene/P computing platform for the case of flow over a single trench topography, enabling direct comparison with complementary experimental data and existing serial multigrid solutions. Parallel performance is assessed as a function of the number of processors employed and shown to lead to super-linear behaviour for the production of mesh-independent solutions. In addition, the approach is used to solve for the case of flow over a complex inter-connected topographical feature and a description provided of how FILMPAR could be adapted relatively simply to solve for a wider class of related thin film flow problems. Program summaryProgram title: FILMPAR Catalogue identifier: AEEL_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEEL_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 530 421 No. of bytes in distributed program, including test data, etc.: 1 960 313 Distribution format: tar.gz Programming language: C++ and MPI Computer: Desktop, server Operating system: Unix/Linux Mac OS X Has the code been vectorised or parallelised?: Yes. Tested with up to 128 processors RAM: 512 MBytes Classification: 12 External routines: GNU C/C++, MPI Nature of problem: Thin film flows over functional substrates containing well-defined single and complex topographical features are of enormous significance, having a wide variety of engineering, industrial and physical applications. However, despite recent modelling advances, the accurate numerical solution of the equations governing such problems is still at a relatively early stage. Indeed, recent studies employing a simplifying long-wave approximation have shown that highly efficient numerical methods are necessary to solve the resulting lubrication equations in order to achieve the level of grid resolution required to accurately capture the effects of micro- and nano-scale topographical features. Solution method: A portable parallel multigrid algorithm has been developed for the above purpose, for the particular case of flow over submerged topographical features. Within the multigrid framework adopted, a W-cycle is used to accelerate convergence in respect of the time dependent nature of the problem, with relaxation sweeps performed using a fixed number of pre- and post-Red-Black Gauss-Seidel Newton iterations. In addition, the algorithm incorporates automatic adaptive time-stepping to avoid the computational expense associated with repeated time-step failure. Running time: 1.31 minutes using 128 processors on BlueGene/P with a problem size of over 16.7 million mesh points.

3-D Surface Visualization of pH Titration "Topos": Equivalence Point Cliffs, Dilution Ramps, and Buffer Plateaus

ERIC Educational Resources Information Center

Smith, Garon C.; Hossain, Md Mainul; MacCarthy, Patrick

2014-01-01

3-D topographic surfaces ("topos") can be generated to visualize how pH behaves during titration and dilution procedures. The surfaces are constructed by plotting computed pH values above a composition grid with volume of base added in one direction and overall system dilution on the other. What emerge are surface features that…

Flow Around Steep Topography

DTIC Science & Technology

2015-09-30

interest in these activities. These tours are being coordinated with the Coral Reef Research Foundation (CRRF), a research organization in Palau...form drag, lee waves , eddy generation) over small-scale topographic features and (ii) fundamentally nonlinear processes (turbulent island wakes...detail in another annual report. From 9 October to 12 November 2015, another SeaSoar cruise on Revelle will focus on wakes and arrested lee waves near

Topology and the Lay of the Land: A Mathematician on the Topographer's Turf.

ERIC Educational Resources Information Center

Shubin, Mikhail

1992-01-01

Presents a proof of Euler's Theorem on polyhedra by relating the theorem to the field of modern topology, specifically to the topology of relief maps. An analogous theorem involving the features of mountain summits, basins, and passes on a terrain is proved and related to the faces, vertices, and edges on a convex polyhedron. (MDH)

Digital Paper Technologies for Topographical Applications

DTIC Science & Technology

2011-09-19

measures examine were training time for each method, time for entry offeatures, procedural errors, handwriting recognition errors, and user preference...time for entry of features, procedural errors, handwriting recognition errors, and user preference. For these metrics, temporal association was...checkbox, text restricted to a specific list of values, etc.) that provides constraints to the handwriting recognizer. When the user fills out the form

Vascular plants and a brief history of the Kiowa and Rita Blanca National Grasslands

Treesearch

Donald L. Hazlett; Michael H. Schiebout; Paulette L. Ford

2009-01-01

Administered by the USDA Forest Service, the Kiowa and Rita Blanca National Grasslands occupy 230,000 acres of public land extending from northeastern New Mexico into the panhandles of Oklahoma and Texas. A mosaic of topographic features including canyons, plateaus, rolling grasslands and outcrops supports a diverse flora. Eight hundred twenty six (826) species of...

Persistent wind-induced enhancement of diffusive CO2 transport in a mountain forest snowpack

Treesearch

D. R. Bowling; W. J. Massman

2011-01-01

Diffusion dominates the transport of trace gases between soil and the atmosphere. Pressure gradients induced by atmospheric flow and wind interacting with topographical features cause a small but persistent bulk flow of air within soil or snow. This forcing, called pressure pumping or wind pumping, leads to a poorly quantified enhancement of gas transport beyond the...

Do the Twist: How a Multimedia Table Could Transform Education

ERIC Educational Resources Information Center

Simkins, Michael

2005-01-01

A group of students is gathered around a square table, on each side of which sit four small maps. In the center is a much larger map. The students are engaged in an animated discussion of key topographical features they are observing and the geological processes that may have produced them. Much pointing and tapping on the table punctuates the…

Land cover associations of nesting territories of three sympatric buteos in shortgrass prairie

USGS Publications Warehouse

McConnell, S.; O'Connell, T. J.; Leslie, David M.

2008-01-01

Three species of Buteo hawks nest sympatrically in the southern Great Plains of the United States. Dietary overlap among them is broad and we tested the hypothesis these species partition their breeding habitat spatially. We compared land cover and topography around 224 nests of the three species breeding in shortgrass prairie in 2004 and 2005. Red-tailed Hawks (Buteo jamaicensis) nested almost exclusively in riparian timber surrounded by prairie (95% prairie land cover around nests) and disproportionately used areas with greater topographic relief within prairie landscapes. Swainson's Hawks (B. swainsoni) commonly nested in low-relief areas dominated by small-grain production agriculture but generally used habitats in proportion to availability. Most nest sites of Ferruginous Hawks (B. regalis) were in prairie (78% prairie land cover around nests), but some were in areas that were at least partially agricultural. Ferruginous Hawks had at least two times more sand sagebrush (Artemisia filifolia) around their nests than their two congeners. We conclude that sympatric breeding Buteos on the southern Great Plains spatially partitioned nest sites according to subtle differences in land cover and topography.

Deglaciation chronology in the Mérida Andes from cosmogenic 10Be dating, (Gavidia valley, Venezuela)

NASA Astrophysics Data System (ADS)

Angel, Isandra; Audemard M., Franck A.; Carcaillet, Julien; Carrillo, Eduardo; Beck, Christian; Audin, Laurence

2016-11-01

In the Mérida Andes, a detailed deglaciation history reconstruction is difficult to achieve due to scattered deglaciation chronologies available. This paper contributes with 24 exposure ages of glacial landforms sampled in the Gavidia valley. Exposure ages were obtained based on terrestrial cosmogenic nuclide 10Be dating. Results indicate deglaciation mainly occurred between ∼21 ka and 16.5 ka and the complete deglaciation occurred at ∼16.0 ka. The glacier retreated in two different phases. The oldest one occurred since the LGM until middle OtD or the local climate event El Caballo Stadial. The youngest phase occurred at ages younger than ∼16.5 ka until complete deglaciation. A combination of topographic features and changes in the paleoclimate conditions at the end of the El Caballo Stadial seems leaded the fastest former glacier extinction. The topographic feature which seems contributed to the fastest glacier extinction was the low valley bottom slopes. In addition, exposure ages of the Gavidia valley were integrated with deglaciation chronologies from the central Mérida Andes to compare deglaciation histories. Asynchronous deglaciation histories were observed. Local paleotemperatures and paleoprecipitations contrasts, different valleys aspects, insolation and catchments steepness could explain different deglaciation histories.

The Development of 3d Sub-Surface Mapping Scheme and its Application to Martian Lobate Debris Aprons

NASA Astrophysics Data System (ADS)

Baik, H.; Kim, J.

2017-07-01

The Shallow Subsurface Radar (SHARAD), a sounding radar equipped on the Mars Reconnaissance Orbiter (MRO), has produced highly valuable information about the Martian subsurface. In particular, the complicated substructures of Mars such as polar deposit, pedestal crater and the other geomorphic features involving possible subsurface ice body has been successfully investigated by SHARAD. In this study, we established a 3D subsurface mapping strategy employing the multiple SHARAD profiles. A number of interpretation components of SHARAD signals were integrated into a subsurface mapping scheme using radargram information and topographic data, then applied over a few mid latitude Lobate Debris Aprons (LDAs). From the identified subsurface layers of LDA, and the GIS data base incorporating the other interpretation outcomes, we are expecting to trace the origin of LDAs. Also, the subsurface mapping scheme developed in this study will be further applied to other interesting Martian geological features such as inter crater structures, aeolian deposits and fluvial sediments. To achieve higher precision sub-surface mapping, the clutter simulation employing the high resolution topographic data and the upgraded clustering algorithms assuming multiple sub-surface layers will be also developed.

Diffraction of SH-waves by topographic features in a layered transversely isotropic half-space

NASA Astrophysics Data System (ADS)

Ba, Zhenning; Liang, Jianwen; Zhang, Yanju

2017-01-01

The scattering of plane SH-waves by topographic features in a layered transversely isotropic (TI) half-space is investigated by using an indirect boundary element method (IBEM). Firstly, the anti-plane dynamic stiffness matrix of the layered TI half-space is established and the free fields are solved by using the direct stiffness method. Then, Green's functions are derived for uniformly distributed loads acting on an inclined line in a layered TI half-space and the scattered fields are constructed with the deduced Green's functions. Finally, the free fields are added to the scattered ones to obtain the global dynamic responses. The method is verified by comparing results with the published isotropic ones. Both the steady-state and transient dynamic responses are evaluated and discussed. Numerical results in the frequency domain show that surface motions for the TI media can be significantly different from those for the isotropic case, which are strongly dependent on the anisotropy property, incident angle and incident frequency. Results in the time domain show that the material anisotropy has important effects on the maximum duration and maximum amplitudes of the time histories.

The chromograph, a new analytical tool for laboratory and field use

USGS Publications Warehouse

Stevens, Rollin Elbert; Lakin, Hubert William

1949-01-01

Water supplies in the Greater Atlanta Region, Georgia, are obtained mainly from surface-water sources, but there is concern that these sources may be unable to meet rising demands. This study indicates that large quantities of good-quality ground water are obtainable from selected sites in the crystalline rocks of the area. Hydrogeologic investigations of 1,051 wells that produce 20 to nearly 500 gallons per minute revealed that large supplies can be developed where favorable structural, stratigraphic, and topographic features result in localized increases in bedrock permeability. These features are described in detail and methods are presented for using them in selecting sites for locating high-producing wells. Most of the site-selection methods are applicable to the north half of the report area, which has rectangular and trellis drainage systems, but their use is restricted in the south half where a dendritic drainage system predominates. Borehole geophysical logs and core drilling revealed that some of the highest production wells derive water from 1- to 8-inch wide horizontal fractures. These fractures occur in a variety of topographic settings and are believed to be stress-relief fractures. (USGS)

A novel algorithm for delineating wetland depressions and ...

EPA Pesticide Factsheets

In traditional watershed delineation and topographic modeling, surface depressions are generally treated as spurious features and simply removed from a digital elevation model (DEM) to enforce flow continuity of water across the topographic surface to the watershed outlets. In reality, however, many depressions in the DEM are actual wetland landscape features that are seldom fully filled with water. For instance, wetland depressions in the Prairie Pothole Region (PPR) are seasonally to permanently flooded wetlands characterized by nested hierarchical structures with dynamic filling- spilling-merging surface-water hydrological processes. The objectives of this study were to delineate hierarchical wetland catchments and model their hydrologic connectivity using high-resolution LiDAR data and aerial imagery. We proposed a novel algorithm delineate the hierarchical wetland catchments and characterize their geometric and topological properties. Potential hydrologic connectivity between wetlands and streams were simulated using the least-cost path algorithm. The resulting flow network delineated putative temporary or seasonal flow paths connecting wetland depressions to each other or to the river network at scales finer than available through the National Hydrography Dataset. The results demonstrated that our proposed framework is promising for improving overland flow modeling and hydrologic connectivity analysis. Presentation at AWRA Spring Specialty Conference in Sn

Spectral reflectance and emissivity features of broad leaf plants: Prospects for remote sensing in the thermal infrared (8.0-14.0 μm)

USGS Publications Warehouse

Ribeiro da Luz, Beatriz; Crowley, James K.

2007-01-01

In contrast to visible and short-wave infrared data, thermal infrared spectra of broad leaf plants show considerable spectral diversity, suggesting that such data eventually could be utilized to map vegetation composition. However, remotely measuring the subtle emissivity features of leaves still presents major challenges. To be successful, sensors operating in the 8–14 μm atmospheric window must have high signal-to-noise and a small enough instantaneous field of view to allow measurements of only a few leaf surfaces. Methods for atmospheric compensation, temperature–emissivity separation, and spectral feature analysis also will need to be refined to allow the recognition, and perhaps, exploitation of leaf thermal infrared spectral properties.

The IMADA-AVER Boundary Layer Experiment in the Mexico City Area.

NASA Astrophysics Data System (ADS)

Doran, J. C.; Bian, X.; de Wekker, S. F. J.; Edgerton, S.; Fast, J. D.; Hubbe, J. M.; Shaw, W. J.; Whiteman, C. D.; Abbott, S.; King, C.; Leach, J.; Mulhearn, M.; Russell, C.; Templeman, B.; Wolfe, D.; Archuleta, J.; Elliott, S.; Fernandez, A.; Langley, D.; Lee, J. T.; Porch, W.; Tellier, L.; Chow, J.; Watson, J. G.; Coulter, R. L.; Martin, T. J.; Shannon, J. D.; White, R.; Martinez, D.; Martinez, J. L.; Mora, V.; Sosa, G.; Mercado, G.; Pena, J. L.; Salas, R.; Petty, R.

1998-11-01

A boundary layer field experiment in the Mexico City basin during the period 24 February-22 March 1997 is described. A total of six sites were instrumented. At four of the sites, 915-MHz radar wind profilers were deployed and radiosondes were released five times per day. Two of these sites also had sodars collocated with the profilers. Radiosondes were released twice per day at a fifth site to the south of the basin, and rawinsondes were flown from another location to the northeast of the city three times per day. Mixed layers grew to depths of 2500-3500 m, with a rapid period of growth beginning shortly before noon and lasting for several hours. Significant differences between the mixed-layer temperatures in the basin and outside the basin were observed. Three thermally and topographically driven flow patterns were observed that are consistent with previously hypothesized topographical and thermal forcing mechanisms. Despite these features, the circulation patterns in the basin important for the transport and diffusion of air pollutants show less day-to-day regularity than had been anticipated on the basis of Mexico City's tropical location, high altitude and strong insolation, and topographical setting.

Unveiling topographical changes using LiDAR mapping capability: case study of Belaga in Sarawak, East-Malaysia

NASA Astrophysics Data System (ADS)

Ganendra, T. R.; Khan, N. M.; Razak, W. J.; Kouame, Y.; Mobarakeh, E. T.

2016-06-01

The use of Light Detection and Ranging (LiDAR) remote sensing technology to scan and map landscapes has proven to be one of the most popular techniques to accurately map topography. Thus, LiDAR technology is the ultimate method of unveiling the surface feature under dense vegetation, and, this paper intends to emphasize the diverse techniques that can be utilized to elucidate topographical changes over the study area, using multi-temporal airborne full waveform LiDAR datasets collected in 2012 and 2014. Full waveform LiDAR data offers access to an almost unlimited number of returns per shot, which enables the user to explore in detail topographical changes, such as vegetation growth measurement. The study also found out topography changes at the study area due to earthwork activities contributing to soil consolidation, soil erosion and runoff, requiring cautious monitoring. The implications of this study not only concurs with numerous investigations undertaken by prominent researchers to improve decision making, but also corroborates once again that investigations employing multi-temporal LiDAR data to unveil topography changes in vegetated terrains, produce more detailed and accurate results than most other remote sensing data.

Interpreting geologic maps for engineering purposes: Hollidaysburg quadrangle, Pennsylvania

USGS Publications Warehouse

,

1953-01-01

This set of maps has been prepared to show the kinds of information, useful to engineers, that can be derived from ordinary geologic maps. A few additional bits of information, drawn from other sources, are mentioned below. Some of the uses of such maps are well known; they are indispensable tools in the modern search for oil or ore deposits; they are the first essential step in unraveling the story of the earth we live on. Less well known, perhaps, is the fact that topographic and geologic maps contain many of the basic data needed for planning any engineering construction job, big or little. Any structure built by man must fit into the topographic and geologic environment shown on such maps. Moreover, most if not all construction jobs must be based on knowledge of the soils and waters, which also are intimately related to this same environment. The topographic map shows the shape of the land the hills and valleys, the streams and swamps, the man-made features such as roads, railroads, and towns. The geologic map shows the kinds and shapes of the rock bodies that form the land surface and that lie beneath it. These are the facts around which the engineer must build.

Scale-location specific relations between soil nutrients and topographic factors in the Fen River Basin, Chinese Loess Plateau

NASA Astrophysics Data System (ADS)

Zhu, Hongfen; Bi, Rutian; Duan, Yonghong; Xu, Zhanjun

2017-06-01

Understanding scale- and location-specific variations of soil nutrients in cultivated land is a crucial consideration for managing agriculture and natural resources effectively. In the present study, wavelet coherency was used to reveal the scale-location specific correlations between soil nutrients, including soil organic matter (SOM), total nitrogen (TN), available phosphorus (AP), and available potassium (AK), as well as topographic factors (elevation, slope, aspect, and wetness index) in the cultivated land of the Fen River Basin in Shanxi Province, China. The results showed that SOM, TN, AP, and AK were significantly inter-correlated, and that the scales at which soil nutrients were correlated differed in different landscapes, and were generally smaller in topographically rougher terrain. All soil nutrients but TN were significantly influenced by the wetness index at relatively large scales (32-72 km) and AK was significantly affected by the aspect at large scales at partial locations, showing localized features. The results of this study imply that the wetness index should be taken into account during farming practices to improve the soil nutrients of cultivated land in the Fen River Basin at large scales.

Print Advertisements for Alzheimer’s Disease Drugs: Informational and Transformational Features

PubMed Central

Gooblar, Jonathan; Carpenter, Brian D.

2014-01-01

Purpose We examined print advertisements for Alzheimer’s disease drugs published in journals and magazines between January 2008 and February 2012, using an informational versus transformational theoretical framework to identify objective and persuasive features. Methods In 29 unique advertisements, we used qualitative methods to code and interpret identifying information, charts, benefit and side effect language, and persuasive appeals embedded in graphics and narratives. Results Most elements contained a mixture of informational and transformational features. Charts were used infrequently, but when they did appear the accompanying text often exaggerated the data. Benefit statements covered an array of symptoms, drug properties, and caregiver issues. Side effect statements often used positive persuasive appeals. Graphics and narrative features emphasized positive emotions and outcomes. Implications We found subtle and sophisticated attempts both to educate and to persuade readers. It is important for consumers and prescribing physicians to read print advertisements critically so that they can make informed treatment choices. PMID:23687184

Print advertisements for Alzheimer's disease drugs: informational and transformational features.

PubMed

Gooblar, Jonathan; Carpenter, Brian D

2013-06-01

We examined print advertisements for Alzheimer's disease drugs published in journals and magazines between January 2008 and February 2012, using an informational versus transformational theoretical framework to identify objective and persuasive features. In 29 unique advertisements, we used qualitative methods to code and interpret identifying information, charts, benefit and side effect language, and persuasive appeals embedded in graphics and narratives. Most elements contained a mixture of informational and transformational features. Charts were used infrequently, but when they did appear the accompanying text often exaggerated the data. Benefit statements covered an array of symptoms, drug properties, and caregiver issues. Side effect statements often used positive persuasive appeals. Graphics and narrative features emphasized positive emotions and outcomes. We found subtle and sophisticated attempts both to educate and to persuade readers. It is important for consumers and prescribing physicians to read print advertisements critically so that they can make informed treatment choices.

Effect of Alkali-Acid-Heat Chemical Surface Treatment on Electron Beam Melted Porous Titanium and Its Apatite Forming Ability

PubMed Central

Bsat, Suzan; Amin Yavari, Saber; Munsch, Maximilian; Valstar, Edward R.; Zadpoor, Amir A.

2015-01-01

Advanced additive manufacturing techniques such as electron beam melting (EBM), can produce highly porous structures that resemble the mechanical properties and structure of native bone. However, for orthopaedic applications, such as joint prostheses or bone substitution, the surface must also be bio-functionalized to promote bone growth. In the current work, EBM porous Ti6Al4V alloy was exposed to an alkali acid heat (AlAcH) treatment to bio-functionalize the surface of the porous structure. Various molar concentrations (3, 5, 10M) and immersion times (6, 24 h) of the alkali treatment were used to determine optimal parameters. The apatite forming ability of the samples was evaluated using simulated body fluid (SBF) immersion testing. The micro-topography and surface chemistry of AlAcH treated samples were evaluated before and after SBF testing using scanning electron microscopy and energy dispersive X-ray spectroscopy. The AlAcH treatment successfully modified the topographical and chemical characteristics of EBM porous titanium surface creating nano-topographical features ranging from 200–300 nm in size with a titania layer ideal for apatite formation. After 1 and 3 week immersion in SBF, there was no Ca or P present on the surface of as manufactured porous titanium while both elements were present on all AlAcH treated samples except those exposed to 3M, 6 h alkali treatment. An increase in molar concentration and/or immersion time of alkali treatment resulted in an increase in the number of nano-topographical features per unit area as well as the amount of titania on the surface. PMID:28788021

Environmental characteristics drive variation in Amazonian understorey bird assemblages

PubMed Central

Magnusson, William E.; Anderson, Marti J.; Schlegel, Martin; Pe’er, Guy; Henle, Klaus

2017-01-01

Tropical bird assemblages display patterns of high alpha and beta diversity and, as tropical birds exhibit strong habitat specificity, their spatial distributions are generally assumed to be driven primarily by environmental heterogeneity and interspecific interactions. However, spatial distributions of some Amazonian forest birds are also often restricted by large rivers and other large-scale topographic features, suggesting that dispersal limitation may also play a role in driving species’ turnover. In this study, we evaluated the effects of environmental characteristics, topographic and spatial variables on variation in local assemblage structure and diversity of birds in an old-growth forest in central Amazonia. Birds were mist-netted in 72 plots distributed systematically across a 10,000 ha reserve in each of three years. Alpha diversity remained stable through time, but species composition changed. Spatial variation in bird-assemblage structure was significantly related to environmental and topographic variables but not strongly related to spatial variables. At a broad scale, we found bird assemblages to be significantly distinct between two watersheds that are divided by a central ridgeline. We did not detect an effect of the ridgeline per se in driving these patterns, indicating that most birds are able to fly across it, and that differences in assemblage structure between watersheds may be due to unmeasured environmental variables or unique combinations of measured variables. Our study indicates that complex geography and landscape features can act together with environmental variables to drive changes in the diversity and composition of tropical bird assemblages at local scales, but highlights that we still know very little about what makes different parts of tropical forest suitable for different species. PMID:28225774

Analysis of open-pit mines using high-resolution topography from UAV

NASA Astrophysics Data System (ADS)

Chen, Jianping; Li, Ke; Sofia, Giulia; Tarolli, Paolo

2015-04-01

Among the anthropogenic topographic signatures on the Earth, open-pit mines deserve a great importance, since they significantly affect the Earth's surface and its related processes (e.g. erosion, pollution). Their geomorphological analysis, therefore, represents a real challenge for the Earth science community. The purpose of this research is to characterize the open-pit mining features using a recently published landscape metric, the Slope Local Length of Auto-Correlation (SLLAC) (Sofia et al., 2014), and high-resolution DEMs (Digital Elevation Models) derived from drone surveyed topography. The research focuses on two main case studies of iron mines located in the Beijing district (P.R. China). The main topographic information (Digital Surface Models, DSMs) was derived using Unmanned Aerial Vehicle (UAV) and the Structure from Motion (SfM) photogrammetric technique. The results underline the effectiveness of the adopted methodologies and survey techniques in the characterization of the main geomorphic features of the mines. Thanks to the SLLAC, the terraced area given by multi-benched sideways-moving method for the iron extraction is automatically depicted, and using some SLLAC derived parameters, the related terraces extent is automatically estimated. The analysis of the correlation length orientation, furthermore, allows to identify the terraces orientation respect to the North, and to understand as well the shape of the open-pit area. This provides a basis for a large scale and low cost topographic survey for a sustainable environmental planning and, for example, for the mitigation of environmental anthropogenic impact due to mining. References Sofia G., Marinello F, Tarolli P. 2014. A new landscape metric for the identification of terraced sites: the Slope Local Length of Auto-Correlation (SLLAC). ISPRS Journal of Photogrammetry and Remote Sensing, doi:10.1016/j.isprsjprs.2014.06.018

Morphological analysis of hummocks in debris avalanche deposits using UAS-derived high-definition topographic data

NASA Astrophysics Data System (ADS)

Hayakawa, Yuichi S.; Obanawa, Hiroyuki; Yoshida, Hidetsugu; Naruhashi, Ryutaro; Okumura, Koji; Zaiki, Masumi

2016-04-01

Debris avalanche caused by sector collapse of a volcanic mountain often forms depositional landforms with characteristic surface morphology comprising hummocks. Geomorphological and sedimentological analyses of debris avalanche deposits (DAD) at the northeastern face of Mt. Erciyes in central Turkey have been performed to investigate the mechanisms and processes of the debris avalanche. The morphometry of hummocks provides an opportunity to examine the volumetric and kinematic characteristics of the DAD. Although the exact age has been unknown, the sector collapse of this DAD was supposed to have occurred in the late Pleistocene (sometime during 90-20 ka), and subsequent sediment supply from the DAD could have affected ancient human activities in the downstream basin areas. In order to measure detailed surface morphology and depositional structures of the DAD, we apply structure-from-motion multi-view stereo (SfM-MVS) photogrammetry using unmanned aerial system (UAS) and a handheld camera. The UAS, including small unmanned aerial vehicle (sUAV) and a digital camera, provides low-altitude aerial photographs to capture surface morphology for an area of several square kilometers. A high-resolution topographic data, as well as an orthorectified image, of the hummocks were then obtained from the digital elevation model (DEM), and the geometric features of the hummocks were examined. A handheld camera is also used to obtain photographs of outcrop face of the DAD along a road to support the seimentological investigation. The three-dimensional topographic models of the outcrop, with a panoramic orthorectified image projected on a vertical plane, were obtained. This data enables to effectively describe sedimentological structure of the hummock in DAD. The detailed map of the DAD is also further examined with a regional geomorphological map to be compared with other geomorphological features including fluvial valleys, terraces, lakes and active faults.

Detecting Small-Scale Topographic Changes and Relict Geomorphic Features on Barrier Islands Using SAR

NASA Technical Reports Server (NTRS)

Gibeaut, James C.; Crawford, Melba M.; Gutierrez, Roberto; Slatton, K. Clint; Neuenschwander, Amy L.; Ricard, Michael R.

1997-01-01

The shapes and elevations of barrier islands may change dramatically over a short period of time during a storm. Coastal scientists and engineers, however, are currently unable to measure these changes occurring over an entire barrier island at once. This three-year project, which is funded by NASA and jointly conducted by the Bureau of Economic Geology and the Center for Space Research at The University of Texas at Austin, is designed to overcome this problem by developing the use of interferometry from airborne synthetic aperture radar (AIRSAR) to measure coastal topography and to detect storm-induced changes in topography. Surrogate measures of topography observed in multiband, fully polarimetric AIRSAR (This type of data are now referred to as POLSAR data.) are also being investigated. Digital elevation models (DEM) of Galveston Island and Bolivar Peninsula, Texas obtained with Topographic SAR (TOPSAR) are compared with measurements by Global Positioning System (GPS) ground surveys and electronic total station surveys. In addition to topographic mapping, this project is evaluating the use of POLSAR to detect old features such as storm scarps, storm channels, former tidal inlets, and beach ridges that have been obscured by vegetation, erosion, deposition, and artificial filling. We have also expanded the work from the original proposal to include the mapping of coastal wetland vegetation and depositional environments. Methods developed during this project will provide coastal geologists with an unprecedented tool for monitoring and understanding barrier island systems. This understanding will improve overall coastal management policies and will help reduce the effects of natural and man-induced coastal hazards. This report summarizes our accomplishments during the second year of the study. Also included is a discussion of our planned activities for year 3 and a revised budget.

Effect of Alkali-Acid-Heat Chemical Surface Treatment on Electron Beam Melted Porous Titanium and Its Apatite Forming Ability.

PubMed

Bsat, Suzan; Yavari, Saber Amin; Munsch, Maximilian; Valstar, Edward R; Zadpoor, Amir A

2015-04-08

Advanced additive manufacturing techniques such as electron beam melting (EBM), can produce highly porous structures that resemble the mechanical properties and structure of native bone. However, for orthopaedic applications, such as joint prostheses or bone substitution, the surface must also be bio-functionalized to promote bone growth. In the current work, EBM porous Ti6Al4V alloy was exposed to an alkali acid heat (AlAcH) treatment to bio-functionalize the surface of the porous structure. Various molar concentrations (3, 5, 10M) and immersion times (6, 24 h) of the alkali treatment were used to determine optimal parameters. The apatite forming ability of the samples was evaluated using simulated body fluid (SBF) immersion testing. The micro-topography and surface chemistry of AlAcH treated samples were evaluated before and after SBF testing using scanning electron microscopy and energy dispersive X-ray spectroscopy. The AlAcH treatment successfully modified the topographical and chemical characteristics of EBM porous titanium surface creating nano-topographical features ranging from 200-300 nm in size with a titania layer ideal for apatite formation. After 1 and 3 week immersion in SBF, there was no Ca or P present on the surface of as manufactured porous titanium while both elements were present on all AlAcH treated samples except those exposed to 3M, 6 h alkali treatment. An increase in molar concentration and/or immersion time of alkali treatment resulted in an increase in the number of nano-topographical features per unit area as well as the amount of titania on the surface.

Topographic controls on overland flow generation in a forest - An ensemble tree approach

NASA Astrophysics Data System (ADS)

Loos, Martin; Elsenbeer, Helmut

2011-10-01

SummaryOverland flow is an important hydrological pathway in many forests of the humid tropics. Its generation is subject to topographic controls at differing spatial scales. Our objective was to identify such controls on the occurrence of overland flow in a lowland tropical rainforest. To this end, we installed 95 overland flow detectors (OFDs) in four nested subcatchments of the Lutzito catchment on Barro Colorado Island, Panama, and monitored the frequency of overland flow occurrence during 18 rainfall events at each OFD location temporal frequency. For each such location, we derived three non-digital terrain attributes and 17 digital ones, of which 15 were based on Digital Elevation Models (DEMs) of three different resolutions. These attributes then served as input into a Random Forest ensemble tree model to elucidate the importance and partial and joint dependencies of topographic controls for overland flow occurrence. Lutzito features a high median temporal frequency in overland flow occurrence of 0.421 among OFD locations. However, spatial temporal frequencies of overland flow occurrence vary strongly among these locations and the subcatchments of Lutzito catchment. This variability is best explained by (1) microtopography, (2) coarse terrain sloping and (3) various measures of distance-to-channel, with the contribution of all other terrain attributes being small. Microtopographic features such as concentrated flowlines and wash areas produce highest temporal frequencies, whereas the occurrence of overland flow drops sharply for flow distances and terrain sloping beyond certain threshold values. Our study contributes to understanding both the spatial controls on overland flow generation and the limitations of terrain attributes for the spatially explicit prediction of overland flow frequencies.

Anticipated Electrical Environment Within Permanently Shadowed Lunar Craters

NASA Technical Reports Server (NTRS)

Farrell, W. M.; Stubbs, T. J.; Halekas, J. S.; Killen, R. M.; Delory, G. T.; Collier, M. R.; Vondrak, R. R.

2010-01-01

Shadowed locations ncar the lunar poles arc almost certainly electrically complex regions. At these locations near the terminator, the local solar wind flows nearly tangential to the surface and interacts with large-scale topographic features such as mountains and deep large craters, In this work, we study the solar wind orographic effects from topographic obstructions along a rough lunar surface, On the leeward side of large obstructions, plasma voids are formed in the solar wind because of the absorption of plasma on the upstream surface of these obstacles, Solar wind plasma expands into such voids) producing an ambipolar potential that diverts ion flow into the void region. A surface potential is established on these leeward surfaces in order to balance the currents from the expansion-limited electron and ion populations, Wc find that there arc regions ncar the leeward wall of the craters and leeward mountain faces where solar wind ions cannot access the surface, leaving an electron-rich plasma previously identified as an "electron cloud." In this case, some new current is required to complete the closure for current balance at the surface, and we propose herein that lofted negatively charged dust is one possible (nonunique) compensating current source. Given models for both ambipolar and surface plasma processes, we consider the electrical environment around the large topographic features of the south pole (including Shoemaker crater and the highly varied terrain near Nobile crater), as derived from Goldstone radar data, We also apply our model to moving and stationary objects of differing compositions located on the surface and consider the impact of the deflected ion flow on possible hydrogen resources within the craters

Physical controls and predictability of stream hyporheic flow evaluated with a multiscale model

USGS Publications Warehouse

Stonedahl, Susa H.; Harvey, Judson W.; Detty, Joel; Aubeneau, Antoine; Packman, Aaron I.

2012-01-01

Improved predictions of hyporheic exchange based on easily measured physical variables are needed to improve assessment of solute transport and reaction processes in watersheds. Here we compare physically based model predictions for an Indiana stream with stream tracer results interpreted using the Transient Storage Model (TSM). We parameterized the physically based, Multiscale Model (MSM) of stream-groundwater interactions with measured stream planform and discharge, stream velocity, streambed hydraulic conductivity and porosity, and topography of the streambed at distinct spatial scales (i.e., ripple, bar, and reach scales). We predicted hyporheic exchange fluxes and hyporheic residence times using the MSM. A Continuous Time Random Walk (CTRW) model was used to convert the MSM output into predictions of in stream solute transport, which we compared with field observations and TSM parameters obtained by fitting solute transport data. MSM simulations indicated that surface-subsurface exchange through smaller topographic features such as ripples was much faster than exchange through larger topographic features such as bars. However, hyporheic exchange varies nonlinearly with groundwater discharge owing to interactions between flows induced at different topographic scales. MSM simulations showed that groundwater discharge significantly decreased both the volume of water entering the subsurface and the time it spent in the subsurface. The MSM also characterized longer timescales of exchange than were observed by the tracer-injection approach. The tracer data, and corresponding TSM fits, were limited by tracer measurement sensitivity and uncertainty in estimates of background tracer concentrations. Our results indicate that rates and patterns of hyporheic exchange are strongly influenced by a continuum of surface-subsurface hydrologic interactions over a wide range of spatial and temporal scales rather than discrete processes.

Icy Islands reveal similar volatile behavior on Pluto and Mars

NASA Astrophysics Data System (ADS)

Sori, M.; Bapst, J.; Byrne, S.

2017-12-01

Ice deposits on planetary surfaces may hold paleoclimate records and elucidate important geologic processes involving volatiles, atmospheres, topography, and climate. Sputnik Planitia on Pluto and the well-studied north and south polar layered deposits (NPLD and SPLD) of Mars are examples. Ice peripheral to these main deposits may be even more sensitive to climatic changes. At northern martian latitudes, 18 outlying H2O ice mounds have previously been mapped within impact craters (Fig. 1a) near the NPLD. Here, we use remote sensing observations from New Horizons and Mars orbital spacecraft to study similar features in craters near Sputnik Planitia and the SPLD. We identify tens of outlying topographic mounds in craters near the SPLD (Fig. 1b) and five bright albedo features in craters near Sputnik Planitia (Fig. 1c). We assess the possibility that these deposits are analogous to the H2O ice mounds at northern martian polar latitudes. The southern martian deposits are physically diverse, but always include convex topography and host craters >15 km in diameter. We interpret at least some of them to be composed of H2O ice like their northern counterparts. The five features on Pluto are located in similarly sized craters and have corresponding spectral detections of N2 ice. One (Fig. 1c) has topography very similar to martian ice mounds, including a convex shape up to 160 m thick. We conclude it is an N2 ice mound, equivalent to Mars' H2O ice mounds in that crater topography provides a favorable microclimate for volatiles. The mound may preserve a paleoclimate record that would be erased in Sputnik Planitia by convection. Using a finite element model, we estimate flow velocities of this N2 ice mound to be 1 cm/yr, implying it may be younger than the other four which could have topography subdued by viscous relaxation. We compare the properties and possible formation mechanisms of these features to test the hypothesis that Pluto's ice cycle is similar to Mars' in certain periods of its orbital history. Figure 1. THEMIS images of ice mounds in the martian craters (a) Louth and (b) Deseado near the NPLD and SPLD, with extracted MOLA topographic profiles. (c) New Horizons base map of the five outlying volatile deposits in craters on Pluto, with extracted topographic profile from crater 3 and corresponding ice flow simulation.

Cocaine Exposure Is Associated with Subtle Compromises of Infants' and Mothers' Social-Emotional Behavior and Dyadic Features of Their Interaction in the Face-to-Face Still-Face Paradigm

ERIC Educational Resources Information Center

Tronick, E. Z.; Messinger, D. S.; Weinberg, M. K.; Lester, B. M.; LaGasse, L.; Seifer, R.; Bauer, C. R.; Shankaran, S.; Bada, H.; Wright, L. L.; Poole, K.; Liu, J.

2005-01-01

Prenatal cocaine and opiate exposure are thought to subtly compromise social and emotional development. The authors observed a large sample of 236 cocaine-exposed and 459 nonexposed infants (49 were opiate exposed and 646 nonexposed) with their mothers in the face-to-face still-face paradigm. Infant and maternal behaviors were microanalytically…

Mathematical Modelling of Arctic Polygonal Tundra with Ecosys: 2. Microtopography Determines How CO 2 and CH 4 Exchange Responds to Changes in Temperature and Precipitation

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

Grant, R. F.; Mekonnen, Z. A.; Riley, W. J.

Differences of surface elevation in arctic polygonal landforms cause spatial variation in soil water contents (θ), active layer depths (ALD), and thereby in CO 2 and CH 4 exchange. In this paper, we test hypotheses in ecosys for topographic controls on CO 2 and CH 4 exchange in trough, rim, and center features of low- and flat-centered polygons (LCP and FCP) against chamber and eddy covariance (EC) measurements during 2013 at Barrow, Alaska. Larger CO 2 influxes and CH 4 effluxes were measured with chambers and modeled with ecosys in LCPs than in FCPs and in lower features (troughs) thanmore » in higher (rims) within LCPs and FCPs. Spatially aggregated CO 2 and CH 4 fluxes from ecosys were significantly correlated with EC flux measurements. Lower features were modeled as C sinks (52–56 g C m -2 yr -1) and CH 4 sources (4–6 g C m -2 yr -1), and higher features as near C neutral (-2–15 g C m -2 yr -1) and CH 4 neutral (0.0–0.1 g C m -2 yr -1). Much of the spatial and temporal variations in CO 2 and CH 4 fluxes were modeled from topographic effects on water and snow movement and thereby on θ, ALD, and soil O 2 concentrations. Model results forced with meteorological data from 1981 to 2015 indicated increasing net primary productivity in higher features and CH 4 emissions in some lower and higher features since 2008, attributed mostly to recent rises in precipitation. Finally, small-scale variation in surface elevation causes large spatial variation of greenhouse gas (GHG) exchanges and therefore should be considered in estimates of GHG exchange in polygonal landscapes.« less

Mathematical Modelling of Arctic Polygonal Tundra with Ecosys: 2. Microtopography Determines How CO 2 and CH 4 Exchange Responds to Changes in Temperature and Precipitation

DOE PAGES

Grant, R. F.; Mekonnen, Z. A.; Riley, W. J.; ...

2017-11-17

Differences of surface elevation in arctic polygonal landforms cause spatial variation in soil water contents (θ), active layer depths (ALD), and thereby in CO 2 and CH 4 exchange. In this paper, we test hypotheses in ecosys for topographic controls on CO 2 and CH 4 exchange in trough, rim, and center features of low- and flat-centered polygons (LCP and FCP) against chamber and eddy covariance (EC) measurements during 2013 at Barrow, Alaska. Larger CO 2 influxes and CH 4 effluxes were measured with chambers and modeled with ecosys in LCPs than in FCPs and in lower features (troughs) thanmore » in higher (rims) within LCPs and FCPs. Spatially aggregated CO 2 and CH 4 fluxes from ecosys were significantly correlated with EC flux measurements. Lower features were modeled as C sinks (52–56 g C m -2 yr -1) and CH 4 sources (4–6 g C m -2 yr -1), and higher features as near C neutral (-2–15 g C m -2 yr -1) and CH 4 neutral (0.0–0.1 g C m -2 yr -1). Much of the spatial and temporal variations in CO 2 and CH 4 fluxes were modeled from topographic effects on water and snow movement and thereby on θ, ALD, and soil O 2 concentrations. Model results forced with meteorological data from 1981 to 2015 indicated increasing net primary productivity in higher features and CH 4 emissions in some lower and higher features since 2008, attributed mostly to recent rises in precipitation. Finally, small-scale variation in surface elevation causes large spatial variation of greenhouse gas (GHG) exchanges and therefore should be considered in estimates of GHG exchange in polygonal landscapes.« less

Predicting the Occurrence of Cave-Inhabiting Fauna Based on Features of the Earth Surface Environment.

PubMed

Christman, Mary C; Doctor, Daniel H; Niemiller, Matthew L; Weary, David J; Young, John A; Zigler, Kirk S; Culver, David C

2016-01-01

One of the most challenging fauna to study in situ is the obligate cave fauna because of the difficulty of sampling. Cave-limited species display patchy and restricted distributions, but it is often unclear whether the observed distribution is a sampling artifact or a true restriction in range. Further, the drivers of the distribution could be local environmental conditions, such as cave humidity, or they could be associated with surface features that are surrogates for cave conditions. If surface features can be used to predict the distribution of important cave taxa, then conservation management is more easily obtained. We examined the hypothesis that the presence of major faunal groups of cave obligate species could be predicted based on features of the earth surface. Georeferenced records of cave obligate amphipods, crayfish, fish, isopods, beetles, millipedes, pseudoscorpions, spiders, and springtails within the area of Appalachian Landscape Conservation Cooperative in the eastern United States (Illinois to Virginia and New York to Alabama) were assigned to 20 x 20 km grid cells. Habitat suitability for these faunal groups was modeled using logistic regression with twenty predictor variables within each grid cell, such as percent karst, soil features, temperature, precipitation, and elevation. Models successfully predicted the presence of a group greater than 65% of the time (mean = 88%) for the presence of single grid cell endemics, and for all faunal groups except pseudoscorpions. The most common predictor variables were latitude, percent karst, and the standard deviation of the Topographic Position Index (TPI), a measure of landscape rugosity within each grid cell. The overall success of these models points to a number of important connections between the surface and cave environments, and some of these, especially soil features and topographic variability, suggest new research directions. These models should prove to be useful tools in predicting the presence of species in understudied areas.

Predicting the Occurrence of Cave-Inhabiting Fauna Based on Features of the Earth Surface Environment

PubMed Central

Doctor, Daniel H.; Niemiller, Matthew L.; Weary, David J.; Young, John A.; Zigler, Kirk S.

2016-01-01

One of the most challenging fauna to study in situ is the obligate cave fauna because of the difficulty of sampling. Cave-limited species display patchy and restricted distributions, but it is often unclear whether the observed distribution is a sampling artifact or a true restriction in range. Further, the drivers of the distribution could be local environmental conditions, such as cave humidity, or they could be associated with surface features that are surrogates for cave conditions. If surface features can be used to predict the distribution of important cave taxa, then conservation management is more easily obtained. We examined the hypothesis that the presence of major faunal groups of cave obligate species could be predicted based on features of the earth surface. Georeferenced records of cave obligate amphipods, crayfish, fish, isopods, beetles, millipedes, pseudoscorpions, spiders, and springtails within the area of Appalachian Landscape Conservation Cooperative in the eastern United States (Illinois to Virginia and New York to Alabama) were assigned to 20 x 20 km grid cells. Habitat suitability for these faunal groups was modeled using logistic regression with twenty predictor variables within each grid cell, such as percent karst, soil features, temperature, precipitation, and elevation. Models successfully predicted the presence of a group greater than 65% of the time (mean = 88%) for the presence of single grid cell endemics, and for all faunal groups except pseudoscorpions. The most common predictor variables were latitude, percent karst, and the standard deviation of the Topographic Position Index (TPI), a measure of landscape rugosity within each grid cell. The overall success of these models points to a number of important connections between the surface and cave environments, and some of these, especially soil features and topographic variability, suggest new research directions. These models should prove to be useful tools in predicting the presence of species in understudied areas. PMID:27532611

Predicting the occurrence of cave-inhabiting fauna based on features of the earth surface environment

USGS Publications Warehouse

Christman, Mary C.; Doctor, Daniel H.; Niemiller, Matthew L.; Weary, David J.; Young, John A.; Zigler, Kirk S.; Culver, David C.

2016-01-01

One of the most challenging fauna to study in situ is the obligate cave fauna because of the difficulty of sampling. Cave-limited species display patchy and restricted distributions, but it is often unclear whether the observed distribution is a sampling artifact or a true restriction in range. Further, the drivers of the distribution could be local environmental conditions, such as cave humidity, or they could be associated with surface features that are surrogates for cave conditions. If surface features can be used to predict the distribution of important cave taxa, then conservation management is more easily obtained. We examined the hypothesis that the presence of major faunal groups of cave obligate species could be predicted based on features of the earth surface. Georeferenced records of cave obligate amphipods, crayfish, fish, isopods, beetles, millipedes, pseudoscorpions, spiders, and springtails within the area of Appalachian Landscape Conservation Cooperative in the eastern United States (Illinois to Virginia and New York to Alabama) were assigned to 20 x 20 km grid cells. Habitat suitability for these faunal groups was modeled using logistic regression with twenty predictor variables within each grid cell, such as percent karst, soil features, temperature, precipitation, and elevation. Models successfully predicted the presence of a group greater than 65% of the time (mean = 88%) for the presence of single grid cell endemics, and for all faunal groups except pseudoscorpions. The most common predictor variables were latitude, percent karst, and the standard deviation of the Topographic Position Index (TPI), a measure of landscape rugosity within each grid cell. The overall success of these models points to a number of important connections between the surface and cave environments, and some of these, especially soil features and topographic variability, suggest new research directions. These models should prove to be useful tools in predicting the presence of species in understudied areas.

Automated Interpretation and Extraction of Topographic Information from Time of Flight Secondary Ion Mass Spectrometry Data

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

Ievlev, Anton V.; Belianinov, Alexei; Jesse, Stephen

Time of flight secondary ion mass spectrometry (ToF SIMS) is one of the most powerful characterization tools allowing imaging of the chemical properties of various systems and materials. It allows precise studies of the chemical composition with sub-100-nm lateral and nanometer depth spatial resolution. However, comprehensive interpretation of ToF SIMS results is challengeable, because of the data volume and its multidimensionality. Furthermore, investigation of the samples with pronounced topographical features are complicated by the spectral shift. In this work we developed approach for the comprehensive ToF SIMS data interpretation based on the data analytics and automated extraction of the samplemore » topography based on time of flight shift. We further applied this approach to investigate correlation between biological function and chemical composition in Arabidopsis roots.« less

Automated Interpretation and Extraction of Topographic Information from Time of Flight Secondary Ion Mass Spectrometry Data

DOE PAGES

Ievlev, Anton V.; Belianinov, Alexei; Jesse, Stephen; ...

2017-12-06

Time of flight secondary ion mass spectrometry (ToF SIMS) is one of the most powerful characterization tools allowing imaging of the chemical properties of various systems and materials. It allows precise studies of the chemical composition with sub-100-nm lateral and nanometer depth spatial resolution. However, comprehensive interpretation of ToF SIMS results is challengeable, because of the data volume and its multidimensionality. Furthermore, investigation of the samples with pronounced topographical features are complicated by the spectral shift. In this work we developed approach for the comprehensive ToF SIMS data interpretation based on the data analytics and automated extraction of the samplemore » topography based on time of flight shift. We further applied this approach to investigate correlation between biological function and chemical composition in Arabidopsis roots.« less

New Geologic Map of the Scandia Region of Mars

NASA Technical Reports Server (NTRS)

Tanaka, K. L.; Rodriquez, J. A. P.; Skinner, J. A., Jr.; Hayward, R. K.; Fortezzo, C.; Edmundson, K.; Rosiek, M.

2009-01-01

We have begun work on a sophisti-cated digital geologic map of the Scandia region (Fig. 1) at 1:3,000,000 scale based on post-Viking image and to-pographic datasets. Through application of GIS tools, we will produce a map product that will consist of (1) a printed photogeologic map displaying geologic units and relevant modificational landforms produced by tectonism, erosion, and collapse/mass wasting; (2) a landform geoda-tabase including sublayers of key landform types, attributed with direct measurements of their planform and to-pography using Mars Orbiter Laser Altimeter (MOLA) altimetry data and High-Resolution Stereo Camera (HRSC) digital elevation models (DEMs) and various image datasets; and (3) a series of digital, reconstructed paleostratigraphic and paleotopographic maps showing the inferred distribution and topographic form of materi-als and features during past ages

Participation in the Mars data analysis program: Global and regional studies of wind-indicators on the surface of Mars

NASA Technical Reports Server (NTRS)

Veverka, J.; Thomas, P.

1984-01-01

Global and regional patterns on Mars were inferred from surface aeolian features, such as wind streaks and dune deposits, which were visible in Viking Orbiter images. Precise measurements of the dimensions of topographic obstacles, i.e., craters, hills, ridges, on Mars as well as their associated wind streaks were used to determine the aerodynamic shape of an obstacle affects near surface airflow. A classification of Martian wind streaks was developed on the basis of albedo contrast and the presence or absence of either topographic obstacles or sediment deposits at the point of origin of the wind streaks. It was concluded that local meteorological conditions, such as the stability of the atmospheric boundary layer, play a major role in determining why some Martian craters produce depositional wind streaks while others produce erosional ones.

Geometric comparison of deep-seated gravitational spereading features on Mars (Coprates Chasma, Valles Marineris) and Earth (Ornak, Tatra Mountains)

NASA Astrophysics Data System (ADS)

Kromuszczyńska, O.; Mège, D.

2014-04-01

Uphill-facing normal faults scarps and crestal grabens, which are characteristic of deep-seated gravitational spreading (DSGS) of topographic ridges, are described in Coprates Chasma in Valles Marineris, Mars, and Ornak ridge and compared. The vertical offset of normal faults in the Martian instances varies from 40 to 1000 meters, with an average of 300 meters. The terrestrial faults offset is between few teens of centimeters up to 34 meters with an average of 10 meters. The values of horizontal displacement in Coprates Chasma vary from 10 to 680 meters, and at Ornak are in a range between 1 and 20 meters. Such difference corresponds with the difference of ridges scale and is due to the topographic gradient which is one order of magnitude higher on Mars than on Earth.

Venus Chasmata: A Lithospheric Stretching Model

NASA Technical Reports Server (NTRS)

Solomon, S. C.; Head, J. W.

1985-01-01

An outstanding problem for Venus is the characterization of its style of global tectonics, an issue intimately related to the dominant mechanism of lithospheric heat loss. Among the most spectacular and extensive of the major tectonic features on Venus are the chasmata, deep linear valleys generally interpreted to be the products of lithospheric extension and rifting. Systems of chasmata and related features can be traced along several tectonic zones up to 20,000 km in linear extent. A lithospheric stretching model was developed to explain the topographic characteristics of Venus chasmata and to constrain the physical properties of the Venus crust and lithosphere.

A generalized geologic map of Mars

NASA Technical Reports Server (NTRS)

Carr, M. H.; Masursky, H.; Saunders, R. S.

1973-01-01

A generalized geologic map of Mars has been constructed largely on the basis of differences in the topography of the surface. A number of topographic features on Mars whose form is highly diagnostic of their origin are shown. Of particular note are the shield volcanoes and lava plains. In some areas, the original features have been considerably modified by subsequent erosional and tectonic processes. These have not, however, resulted in homogenization of the planet's surface, but rather have emphasized its variegated character by leaving a characteristic imprint in specific areas. The topography of the planet, therefore, lends itself well to remote geologic interpretation.

On the use of high-resolution topographic data as a proxy for seismic site conditions (VS30)

USGS Publications Warehouse

Allen, T.I.; Wald, D.J.

2009-01-01

An alternative method has recently been proposed for evaluating global seismic site conditions, or the average shear velocity to 30 m depth (VS30), from the Shuttle Radar Topography Mission (SRTM) 30 arcsec digital elevation models (DEMs). The basic premise of the method is that the topographic slope can be used as a reliable proxy for VS30 in the absence of geologically and geotechnically based site-condition maps through correlations between VS30 measurements and topographic gradient. Here we evaluate the use of higher-resolution (3 and 9 arcsec) DEMs to examine whether we are able to resolve VS30 in more detail than can be achieved using the lower-resolution SRTM data. High-quality DEMs at resolutions greater than 30 arcsec are not uniformly available at the global scale. However, in many regions where such data exist, they may be employed to resolve finer-scale variations in topographic gradient, and consequently, VS30. We use the U.S. Geological Survey Earth Resources Observation and Science (EROS) Data Center's National Elevation Dataset (NED) to investigate the use of high-resolution DEMs for estimating VS30 in several regions across the United States, including the San Francisco Bay area in California, Los Angeles, California, and St. Louis, Missouri. We compare these results with an example from Taipei, Taiwan, that uses 9 arcsec SRTM data, which are globally available. The use of higher-resolution NED data recovers finer-scale variations in topographic gradient, which better correlate to geological and geomorphic features, in particular, at the transition between hills and basins, warranting their use over 30 arcsec SRTM data where available. However, statistical analyses indicate little to no improvement over lower-resolution topography when compared to VS30 measurements, suggesting that some topographic smoothing may provide more stable VS30 estimates. Furthermore, we find that elevation variability in canopy-based SRTM measurements at resolutions greater than 30 arcsec are too large to resolve reliable slopes, particularly in low-gradient sedimentary basins.

[Role of different scale structures of titanium implant in the biological behaviors of human umbilical vein endothelial cells].

PubMed

Liang, N W; Shi, L; Huang, Y; Deng, X L

2017-02-18

To study the role of different scale structure of Ti implants on the biological behaviors of human umbilical vein endothelial cell (HUVECs) and to reveal the role of material surface topographical features on peri-implant angiogenesis. Titanium (Ti) discs with different surface structures (Ti discs with smooth surface, Ti discs with nano scale structure, Ti discs with micro scale structure and Ti discs with micro/nano scale structure, named as SM-Ti, Nano-Ti, Micro-Ti and Micro/Nano-Ti, respectively) were prepared and their surface topographical features were confirmed via scanning electron microscopy (SEM) observation. HUVECs were cultured on these Ti discs. Biological outcomes of HUVECs on different surfaces were carried out, including cell adhesive capacity, proliferation, vascular endothelial growth factor (VEGF) production and intracellular expression of Ca(2+). The results of SEM images and immunofluorescence double staining of rhodamine-phalloidin and DAPI showed that compared with the SM-Ti and Nano-Ti group, the adhesive capacity and proliferation behavior of HUVECs on the surfaces of Micro-Ti and Micro/Nano-Ti was decreased. The results of culturing HUVECs on different groups of Ti discs after 24 hours showed that the cells number grew from (18±4) to (42±6)/ vision on SM-Ti, (28±6) to (52±10)/vision on Nano-Ti, (20±4) to (21±6)/vision on Micro-Ti and (16±4) to (18±6)/vision on Micro/Nano-Ti. Moreover, compared with the adhesion and proliferation of HUVECs on SM-Ti group and Nano-Ti, the adhesion and proliferation of HUVECs on Micro-Ti group and Micro/Nano-Ti group was significantly reduced (P<0.05).The results of enzyme-linked immunosorbent assay (ELISA) showed that the VEGF productions of SM-Ti, Nano-Ti, Micro-Ti and Micro/Nano-Ti were (690±35) ng/L, (560±20) ng/L, (474±43) ng/L and (517±29) ng/L, respectively. Moreover, compared with the VEGF production of HUVECs on SM-Ti group, the VEGF production of HUVECs on Micro-Ti group and Micro/Nano-Ti group was significantly reduced (P<0.05). The results of Ca(2+) ion detection showed that the Ca(2+) expression of HUVECs on Micro-Ti and Micro/Nano-Ti was significantly higher than that on the surface of SM-Ti and Nano-Ti. These results implied that the over expressed Ca(2+) might contributed to the impaired biological function of HUVECs on Micro-Ti and Micro/Nano-Ti. Different topographical features on titanium influenced the biological behaviors of the HUVECs, which may illustrate how topographical features of Ti implant affect peri-implant angiogenesis. These results also suggest that the biological behaviors of HUVECs might be relative to the changed expression of intracellular Ca(2+).

Calculating erosion rates of river bank sediment by combining field measurements of erodibility parameters and small-scale topographic features – A case study at the Danube River

USDA-ARS?s Scientific Manuscript database

This paper examines the application of a method for calculating fluvial erosion on river banks. In the investigated area the determination of potential erosion rates are essential to estimating the initiated river widening processes and their effect on navigation. A mini-jet device was employed, for...

Graphic representation of STS-99 Endeavour during SRTM

NASA Image and Video Library

2000-02-04

JSC2000E-01557 (January 2000) --- This partially computer-generated scene depicts anticipated coverage by the Shuttle Radar Topography Mission (SRTM) of topographic features on Earth. Heavy cloud cover, hurricanes and cyclonic storms can prevent optical cameras on satellites or aircraft from imaging some areas. SRTM radar, with its long wavelength, will penetrate clouds as well as providing its own illumination, making it independent of daylight.

Scoping of Flood Hazard Mapping Needs for Coos County, New Hampshire

DTIC Science & Technology

2006-01-01

Technical Partner DEM Digital Elevation Model DFIRM Digital Flood Insurance Rate Map DOQ Digital Orthophoto Quadrangle DOQQ Digital Ortho Quarter Quadrangle...color Digital Orthophoto Quadrangles (DOQs)). Remote sensing, base map information, GIS data (for example, contour data, E911 data, Digital Elevation...the feature types found on USGS topographic maps. More recently developed data were derived from digital orthophotos providing improved base map

Map Interpretation and Terrain Analysis Course (MITAC) for Infantrymen: Illustrated Lectures

DTIC Science & Technology

1982-01-01

Factors Influencing Map Design . . . . . ..... ............ 4 Interpretation of Terrain Relief and Other Topographic Features...Institute (ARI) sponsored a project to design and develop a map interpretation and terrain analysis course (MITAC) to improve the ability of Army...helicopter pilots to navigate accurately when flying at nap-of-the-earth (NOE) altitudes (McGrath, 1975; McGrath & Foster, 1975). MITAC was designed to

First results from stellar occultations in the "GAIA era"

NASA Astrophysics Data System (ADS)

Benedetti-Rossi, G.; Vieira-Martins, R.; Sicardy, B.

2017-09-01

Stellar occultation is a powerful technique to study distant solar system bodies. It allows high angular resolution of the occulting body from the analysis of a light curve acquired with high temporal resolution with uncertainties comparable as probes. In the "GAIA era", stellar occultations is now able to obtain even more impressive results such as the presence of atmosphere, rings and topographic features.

The geography and geology of Alaska; a summary of existing knowledge, with a section on climate, and a topographic map and description thereof

USGS Publications Warehouse

Brooks, A.H.; Abbe, Cleveland; Goode, R.U.

1906-01-01

It is the writer's purpose to describe in nontechnical language the larger geographic features and discuss their relation as far as the data available will permit. In the treatment of the geology, however, less effort will be made to make the matter acceptable to the lay reader. It is hoped, however, that a brief summary of the salient features of the geologic history' may be not without interest to the general public. If this paper serves in some measure to dispel the popular fallacies regarding Alaska and to disseminate more accurate knowledge of its geographic and geologic features, the purpose of its publication will be accomplished.

Geological Features Mapping Using PALSAR-2 Data in Kelantan River Basin, Peninsular Malaysia

NASA Astrophysics Data System (ADS)

Pour, A. B.; Hashim, M.

2016-09-01

In this study, the recently launched Phased Array type L-band Synthetic Aperture Radar-2 (PALSAR-2) onboard the Advanced Land Observing Satellite-2 (ALOS-2), remote sensing data were used to map geologic structural and topographical features in the Kelantan river basin for identification of high potential risk and susceptible zones for landslides and flooding areas. A ScanSAR and two fine mode dual polarization level 3.1 images cover Kelantan state were processed for comprehensive analysis of major geological structures and detailed characterizations of lineaments, drainage patterns and lithology at both regional and district scales. Red-Green-Blue (RGB) colour-composite was applied to different polarization channels of PALSAR-2 data to extract variety of geological information. Directional convolution filters were applied to the data for identifying linear features in particular directions and edge enhancement in the spatial domain. Results derived from ScanSAR image indicate that lineament occurrence at regional scale was mainly linked to the N-S trending of the Bentong-Raub Suture Zone (BRSZ) in the west and Lebir Fault Zone in the east of the Kelantan state. Combination of different polarization channels produced image maps contain important information related to water bodies, wetlands and lithological units for the Kelantan state using fine mode observation data. The N-S, NE-SW and NNE-SSW lineament trends were identified in the study area using directional filtering. Dendritic, sub-dendritic and rectangular drainage patterns were detected in the Kelantan river basin. The analysis of field investigations data indicate that many of flooded areas were associated with high potential risk zones for hydro-geological hazards such as wetlands, urban areas, floodplain scroll, meander bend, dendritic and sub-dendritic drainage patterns, which are located in flat topograghy regions. Numerous landslide points were located in rectangular drainage system that associated with topographic slope of metamorphic and Quaternary rock units. Some large landslides were associated with N-S, NNE-SSW and NE-SW trending fault zones. Consequently, structural and topographical geology maps were produced for Kelantan river basin using PALSAR-2 data, which could be broadly applicable for landslide hazard mapping and identification of high potential risk zone for hydro-geological hazards.

The topography of Ceres and implications for the formation of linear surface structures

NASA Astrophysics Data System (ADS)

Buczkowski, D.; Otto, K.; Ruesch, O.; Scully, J. E. C.; Williams, D. A.; Mest, S. C.; Schenk, P.; Jaumann, R.; Nathues, A.; Preusker, F.; Park, R. S.; Raymond, C. A.; Russell, C. T.

2015-12-01

NASA's Dawn spacecraft began orbiting the dwarf planet Ceres in April 2015. Framing Camera data from the Approach (1.3 km/px) and Survey (415 m/px) orbits include digital terrain models derived from processing stereo images. These models have supported various scientific studies of the surface. The eastern hemisphere of Ceres is topographically higher than the western hemisphere. Some of linear structures on Ceres (which include grooves, pit crater chains, fractures and troughs) appear to be radial to the large basins Urvara and Yalode, and most likely formed due to impact processes. However, set of regional linear structures (RLS) that do not have any obvious relationship to impact craters are found on the eastern hemisphere topographic high region. Many of the longer RLS are comprised of smaller structures that have linked together, suggestive of en echelon fractures. Polygonal craters, theorized to form when pervasive subsurface fracturing affects crater formation [1], are widespread on Ceres [2], and those proximal to the RLS have straight crater rims aligned with the grooves and troughs, suggesting that the RLS are fracture systems. A cross-section of one RLS is displayed in FC images of the Occator crater wall. Comparing these images to the digital terrain models show 1) that the structure dips ~60º and 2) there is downward motion on the hanging wall, implying normal faulting. The digital terrain models also reveal the presence of numerous positive relief features with sub-circular shapes. These dome-like features have been tentatively interpreted as volcanic/magmatic features [3]; other possibilities include salt domes. Analog models of domal uplift in areas of regional extension [4] predict patterns of linear structures similar to those observed in the RLS near Occator. Utilizing topography data provided by the Ceres digital terrain models, we assess the relationship between the RLS and nearby domes and topographic high regions to determine the mechanism by which the RLS may have formed. [1] Thomas, P.C. et al. (1999) Icarus, doi: 10.1006/icar.1999.6121 [2] Otto et al. (2015) EPSC2015-284 [3] Ruesch et al. [this meeting] [4] Sims et al. (2013) AAPG Bulletin, doi: 10.1306/02101209136

Constraining the Mean Crustal Thickness on Mercury

NASA Technical Reports Server (NTRS)

Nimmo, F.

2001-01-01

The topography of Mercury is poorly known, with only limited radar and stereo coverage available. However, radar profiles reveal topographic contrasts of several kilometers over wavelengths of approximately 1000 km. The bulk of Mercury's geologic activity took place within the first 1 Ga of the planet's history), and it is therefore likely that these topographic features derive from this period. On Earth, long wavelength topographic features are supported either convectively, or through some combination of isostasy and flexure. Photographic images show no evidence for plume-like features, nor for plate tectonics; I therefore assume that neither convective support nor Pratt isostasy are operating. The composition and structure of the crust of Mercury are almost unknown. The reflectance spectrum of the surface of Mercury is similar to that of the lunar highlands, which are predominantly plagioclase. Anderson et al. used the observed center-of-mass center-of-figure offset together with an assumption of Airy isostasy to infer a crustal thickness of 100-300 km. Based on tidal despinning arguments, the early elastic thickness (T(sub e)) of the (unfractured) lithosphere was approximately equal to or less than 100 km. Thrust faults with lengths of up to 500 km and ages of about 4 Ga B.P. are known to exist on Mercury. Assuming a semicircular slip distribution and a typical thrust fault angle of 10 degrees, the likely vertical depth to the base of these faults is about 45 km. More sophisticated modelling gives similar or slightly smaller answers. The depth to the base of faulting and the elastic layer are usually similar on Earth, and both are thought to be thermally controlled. Assuming that the characteristic temperature is about 750 K, the observed fault depth implies that the heat flux at 4 Ga B.P. is unlikely to be less than 20 mW m(exp -2) for a linear temperature gradient. For an elastic thickness of 45 km, topography at 1000 km wavelength is likely to be about 60% compensated. There are thus likely to be considerable lateral variations in crustal thickness. Additional information is contained in the original extended abstract.

Monitoring gully change: A comparison of airborne and terrestrial laser scanning using a case study from Aratula, Queensland

NASA Astrophysics Data System (ADS)

Goodwin, Nicholas R.; Armston, John D.; Muir, Jasmine; Stiller, Issac

2017-04-01

Airborne laser scanning (ALS) and terrestrial laser scanning (TLS) technologies capture spatially detailed estimates of surface topography and when collected multi-temporally can be used to assess geomorphic change. The sensitivity and repeatability of ALS measurements to characterise geomorphic change in topographically complex environments such as gullies; however, remains an area lacking quantitative research. In this study, we captured coincident ALS and TLS datasets to assess their ability and synergies to detect geomorphic change for a gully located in Aratula, southeast Queensland, Australia. We initially used the higher spatial density and ranging accuracy of TLS to provide an assessment of the Digital Elevation Models (DEM) derived from ALS within a gully environment. Results indicated mean residual errors of 0.13 and 0.09 m along with standard deviation (SD) of residual errors of 0.20 and 0.16 m using pixel sizes of 0.5 and 1.0 m, respectively. The positive mean residual errors confirm that TLS data consistently detected deeper sections of the gully than ALS. We also compared the repeatability of ALS and TLS for characterising gully morphology. This indicated that the sensitivity to detect change using ALS is substantially lower than TLS, as expected, and that the ALS survey characteristics influence the ability to detect change. Notably, we found that using one ALS transect (mean density of 5 points / m2) as opposed to three transects increased the SD of residual error by approximately 30%. The supplied classification of ALS ground points was also demonstrated to misclassify gully features as non-ground, with minimum elevation filtering found to provide a more accurate DEM of the gully. The number and placement of terrestrial laser scans were also found to influence the derived DEMs. Furthermore, we applied change detection using two ALS data captures over a four year period and four TLS field surveys over an eight month period. This demonstrated that ALS can detect large scale erosional changes with head cutting of gully branches migrating approximately 10 m upslope. In comparison, TLS captured smaller scale intra-annual erosional patterns largely undetectable by the ALS dataset with a large rainfall event coinciding with the highest volumetric change (net change > 46 m3). Overall, these findings reaffirm the importance of quantifying DEM errors and demonstrate that ALS is unlikely to detect subtle geomorphic changes (< 0.45 m) potentially missing significant sediment change. TLS was able to detect more subtle intra-annual changes but was limited in its spatial coverage. This suggests TLS and ALS surveys are complementary technologies and when used together can provide a more detailed understanding of gully processes at different temporal and spatial scales, provided the inherent errors are taken into account.

Neuropathology of the recessive A673V APP mutation: Alzheimer disease with distinctive features.

PubMed

Giaccone, Giorgio; Morbin, Michela; Moda, Fabio; Botta, Mario; Mazzoleni, Giulia; Uggetti, Andrea; Catania, Marcella; Moro, Maria Luisa; Redaelli, Veronica; Spagnoli, Alberto; Rossi, Roberta Simona; Salmona, Mario; Di Fede, Giuseppe; Tagliavini, Fabrizio

2010-12-01

Mutations of three different genes, encoding β-amyloid precursor protein (APP), presenilin 1 and presenilin 2 are associated with familial Alzheimer's disease (AD). Recently, the APP mutation A673V has been identified that stands out from all the genetic defects previously reported in these three genes, since it causes the disease only in the homozygous state (Di Fede et al. in Science 323:1473-1477, 2009). We here provide the detailed neuropathological picture of the proband of this family, who was homozygous for the APP A673V mutation and recently came to death. The brain has been studied by histological and immunohistochemical techniques, at the optical and ultrastructural levels. Cerebral Aβ accumulation and tau pathology were severe and extensive. Peculiar features were the configuration of the Aβ deposits that were of large size, mostly perivascular and exhibited a close correspondence between the pattern elicited by amyloid stainings and the labeling obtained with immunoreagents specific for Aβ40 or Aβ42. Moreover, Aβ deposition spared the neostriatum while deeply affecting the cerebellum, and therefore was not in compliance with the hierarchical topographical sequence of involvement documented in sporadic AD. Therefore, the neuropathological picture of familial AD caused by the APP recessive mutation A673V presents distinctive characteristics compared to sporadic AD or familial AD inherited as a dominant trait. Main peculiar features are the morphology, structural properties and composition of the Aβ deposits as well as their topographic distribution in the brain.

Observing the formation of ice and organic crystals in active sites

PubMed Central

Campbell, James M.; Meldrum, Fiona C.; Christenson, Hugo K.

2017-01-01

Heterogeneous nucleation is vital to a wide range of areas as diverse as ice nucleation on atmospheric aerosols and the fabrication of high-performance thin films. There is excellent evidence that surface topography is a key factor in directing crystallization in real systems; however, the mechanisms by which nanoscale pits and pores promote nucleation remain unclear. Here, we use natural cleavage defects on Muscovite mica to investigate the activity of topographical features in the nucleation from vapor of ice and various organic crystals. Direct observation of crystallization within surface pockets using optical microscopy and also interferometry demonstrates that these sharply acute features provide extremely effective nucleation sites and allows us to determine the mechanism by which this occurs. A confined phase is first seen to form along the apex of the wedge and then grows out of the pocket opening to generate a bulk crystal after a threshold saturation has been achieved. Ice nucleation proceeds in a comparable manner, although our resolution is insufficient to directly observe a condensate before the growth of a bulk crystal. These results provide insight into the mechanism of crystal deposition from vapor on real surfaces, where this will ultimately enable us to use topography to control crystal deposition on surfaces. They are also particularly relevant to our understanding of processes such as cirrus cloud formation, where such topographical features are likely candidates for the “active sites” that make clay particles effective nucleants for ice in the atmosphere. PMID:27994140

Microstructure-property relationships in directionally solidified single crystal nickel-base superalloys

NASA Technical Reports Server (NTRS)

Mackay, R. A.; Nathal, M. V.

1986-01-01

Some of the microstructural features which influence the creep properties of directionally solidified and single crystal nickel-base superalloys are discussed. Gamma precipitate size and morphology, gamma-gamma lattice mismatch, phase instability, alloy composition, and processing variations are among the factors considered. Recent experimental results are reviewed and related to the operative deformation mechanisms and to the corresponding mechanical properties. Special emphasis is placed on the creep behavior of single crystal superalloys at high temperatures, where directional gamma coarsening is prominent, and at lower temperatures, where gamma coarsening rates are significantly reduced. It can be seen that very subtle changes in microstructural features can have profound effects on the subsequent properties of these materials.

Investigating the Geomorphic Behavior of the Cape Canaveral Coast Through High-Resolution Beach Monitoring, Sediment Analysis, Oceanographic Observations, and Numerical Modeling

NASA Astrophysics Data System (ADS)

Adams, P. N.; Jaeger, J. M.; MacKenzie, R. A.; Kline, S. W.; Maibauer, B. J.; Plant, N. G.; Gravens, M. B.; Pierro, T. P.; Shaffer, J.

2011-12-01

The salient of Cape Canaveral interrupts a relatively straight, sandy, passive margin coastline that extends nearly 400 km from the St. Johns River mouth to the St. Lucie Inlet along the Florida Atlantic coast. OSL dating indicates that the modern cape has been prograding rapidly since the LGM and subtle topographic features, inland from the modern cape, suggest that this salient has persisted over several sea level cycles since the early Pleistocene. Dynamic shoreline change over the past decade at the Kennedy Space Center (KSC) is threatening critical NASA infrastructure and has prompted officials to develop a mitigation strategy through a partnership among researchers from the U.S. Geological Survey, the U.S. Army Corps of Engineers, private coastal engineering firms, and the University of Florida. Since May 2009, the research team has assembled data on decadal to event-scale shoreline change (dGPS), beach and nearshore morphodynamics (dGPS and Argus), beach sedimentary character (grain size analysis), wave climate and transformation (ADCP), and inner shelf bathymetry (Echo Sounding) in an effort to assess dune vulnerability and flooding risk. In addition, SWAN numerical modeling simulations offer insight into the influence of irregular bathymetry (cape-associated shoals) on the alteration of spatial patterns of wave energy flux during a decadal shift in deep-water wave climate. Beach-fx, modeling of cross-shore profile evolution is being applied to evaluate the performance of alternative protective measures, estimate project costs, and examine ecological influences of the proposed alternative protective measures. By combining contemporaneous data of coastal geomorphic and sedimentary response to wave forcing with numerical model results that explore a range of climate scenarios, we aim to develop a useful understanding of the coastal geomorphic behavior at KSC that can be used to make a mitigation recommendation.

Hazard analysis on the Mid-Atlantic Continental Slope, DCS lease sale 59 Area

USGS Publications Warehouse

Cardinell, Alex P.; Keer, Frederick R.

1982-01-01

A multi-parameter high-resolution seismic survey covering 253 offshore lease blocks was undertaken for analysis of critical structural and depositional features and a suite of piston cores was examined for geotechnical properties on the Mid-Atlantic continental slope in the OCS Lease Sale 59 area. The analysis of this data revealed complex interrelationships between a number of buried structural and depositional features indicating the existence of a variety of slope environments in the proposed lease sale area. The relationship these depositional features have to fault scarps and other topographic irregularities is critical to hazards assessment in this area. Southwest of the Hudson Canyon area, a major slump complex was partially delineated and numerous drape structures, which in some cases appear to have developed into contemporaneous down-to-the-basin faults, are associated with topographic irregularities. Southwest of the Baltimore Canyon area, slumps may be a result of the formation of mud diapers. These diapers? are the first reported in the Mid-Atlantic continental slope. Piston cores were collected at selected locations to provide information on geotechnical strength parameters of slumps, slides, and undisturbed sediments. These data indicate that localized areas of under consolidated sediments are found on valley walls and ridges of the upper slope. These zones may represent discrete areas where either mass movement has occurred or the potential for mass movement may exist. Many of the mass-movement features identified in the OCS Lease Sale 59 area may be Pleistocene in age and are related to' conditions prevailing during low sea stands. Since these conditions are presently absent, the potential for sediment mass movement does not appear to present a major problem to oil and gas operations within the proposed OCS Lease Sale 59 area.

Terra Cimmeria - False Color

NASA Image and Video Library

2016-10-11

The THEMIS VIS camera contains 5 filters. The data from different filters can be combined in multiple ways to create a false color image. These false color images may reveal subtle variations of the surface not easily identified in a single band image. Today's false color image shows dust devil tracks (dark blue linear feature) in Terra Cimmeria. Orbit Number: 43463 Latitude: -53.1551 Longitude: 125.069 Instrument: VIS Captured: 2011-10-01 23:55 http://photojournal.jpl.nasa.gov/catalog/PIA21009

Out-of-time-ordered measurements as a probe of quantum dynamics

NASA Astrophysics Data System (ADS)

Bordia, Pranjal; Alet, Fabien; Hosur, Pavan

2018-03-01

Probing the out-of-equilibrium dynamics of quantum matter has gained renewed interest owing to immense experimental progress in artificial quantum systems. Dynamical quantum measures such as the growth of entanglement entropy and out-of-time-ordered correlators (OTOCs) have been shown to provide great insight by exposing subtle quantum features invisible to traditional measures such as mass transport. However, measuring them in experiments requires either identical copies of the system, an ancilla qubit coupled to the whole system, or many measurements on a single copy, thereby making scalability extremely complex and hence, severely limiting their potential. Here, we introduce an alternative quantity, the out-of-time-ordered measurement (OTOM), which involves measuring a single observable on a single copy of the system, while retaining the distinctive features of the OTOCs. We show, theoretically, that OTOMs are closely related to OTOCs in a doubled system with the same quantum statistical properties as the original system. Using exact diagonalization, we numerically simulate classical mass transport, as well as quantum dynamics through computations of the OTOC, the OTOM, and the entanglement entropy in quantum spin chain models in various interesting regimes (including chaotic and many-body localized systems). Our results demonstrate that an OTOM can successfully reveal subtle aspects of quantum dynamics hidden to classical measures and, crucially, provide experimental access to them.

The Topography Tub Learning Activity

NASA Astrophysics Data System (ADS)

Glesener, G. B.

2014-12-01

Understanding the basic elements of a topographic map (i.e. contour lines and intervals) is just a small part of learning how to use this abstract representational system as a resource in geologic mapping. Interpretation of a topographic map and matching its features with real-world structures requires that the system is utilized for visualizing the shapes of these structures and their spatial orientation. To enrich students' skills in visualizing topography from topographic maps a spatial training activity has been developed that uses 3D objects of various shapes and sizes, a sighting tool, a plastic basin, water, and transparencies. In the first part of the activity, the student is asked to draw a topographic map of one of the 3D objects. Next, the student places the object into a plastic tub in which water is added to specified intervals of height. The shoreline at each interval is used to reference the location of the contour line the student draws on a plastic inkjet transparency directly above the object. A key part of this activity is the use of a sighting tool by the student to assist in keeping the pencil mark directly above the shoreline. It (1) ensures the accurate positioning of the contour line and (2) gives the learner experience with using a sight before going out into the field. Finally, after the student finishes drawing the contour lines onto the transparency, the student can compare and contrast the two maps in order to discover where improvements in their visualization of the contours can be made. The teacher and/or peers can also make suggestions on ways to improve. A number of objects with various shapes and sizes are used in this exercise to produce contour lines representing the different types of topography the student may encounter while field mapping. The intended outcome from using this visualization training activity is improvement in performance of visualizing topography as the student moves between the topographic representation and corresponding topography in the field.

Landsat with SRTM Shaded Relief, Los Angeles and Vicinity from Space

NASA Technical Reports Server (NTRS)

2002-01-01

Los Angeles and vicinity seen from space, as viewed by the Landsat 7 satellite from an altitude of 437 miles on May 4, 2001. North is at the top. Topographic shading has been enhanced using an elevation data set acquired by the Space Shuttle Endeavour in February 2000. Downtown Los Angeles is just south of the image center, with L.A. and Long Beach harbors to the south, Santa Monica Bay to the west, San Fernando Valley to the northwest, San Gabriel Valley to the east, and Orange County to the southeast. The San Andreas fault forms the straight diagonal mountain front bordering the Mojave Desert at the top of the image. At full resolution, features on the ground as small as 15 meters (49 feet) across can be distinguished, including street patterns and large buildings, as well as boats and their wakes on the ocean. More than ten million people live within this scene.

This image was generated by first geographically matching the Landsat scene to a Shuttle Radar Topography Mission (SRTM) elevation model. A measure of topographic slope along a southeast-northwest trend was then calculated, such that southeast facing slopes appear bright and northwest facing slopes appear dark. This slope image was then added to the enhanced Landsat scene in order to intensify the appearance of topography. Topographic shading was subtle in the original Landsat scene due to the fairly high sun angle (63 degrees above the horizon) during the satellite overflight in late morning of a mid-Spring day.

Landsat has been providing visible and infrared views of the Earth since 1972. SRTM elevation data matches the 30-meter (98-foot) resolution of most Landsat images and helps in analyzing the large and growing Landsat image archive, managed by the U.S. Geological Survey (USGS).

Elevation data used in this image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect 3-D measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter (approximately 200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between NASA, the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Earth Science Enterprise, Washington, D.C.

Size: 138.8 kilometers (86.1 miles) by 94.0 kilometers (58.3 miles) Location: 34.1 degrees North latitude, 118.3 degrees West longitude Orientation: North at top Image Data: Landsat bands 3, 2+4, 1 as red, green, blue, respectively, with SRTM shaded relief, plus Landsat panchromatic band 8 added for detail. Original Data Resolution: SRTM 1 arc-second (30 meters or 98 feet), Landsat color 30 meters (98 feet) sharpened with Landsat panchromatic band (15 meters or 49 feet). Date Acquired: May 4, 2001 (Landsat), February 2000 (SRTM)

Wind, Circulation, and Topographic Effects on Alongshore Phytoplankton Variability in the California Current

NASA Astrophysics Data System (ADS)

Fiechter, Jerome; Edwards, Christopher A.; Moore, Andrew M.

2018-04-01

A physical-biogeochemical model is used to produce a retrospective analysis at 3-km resolution of alongshore phytoplankton variability in the California Current during 1988-2010. The simulation benefits from downscaling a regional circulation reanalysis, which provides improved physical ocean state estimates in the high-resolution domain. The emerging pattern is one of local upwelling intensification in response to increased alongshore wind stress in the lee of capes, modulated by alongshore meanders in the geostrophic circulation. While stronger upwelling occurs near most major topographic features, substantial increases in phytoplankton biomass only ensue where local circulation patterns are conducive to on-shelf retention of upwelled nutrients. Locations of peak nutrient delivery and chlorophyll accumulation also exhibit interannual variability and trends noticeably larger than the surrounding shelf regions, thereby suggesting that long-term planktonic ecosystem response in the California Current exhibits a significant local scale (O(100 km)) alongshore component.

Evaluation of ERTS imagery for spectral geological mapping in diverse terranes of New York State

NASA Technical Reports Server (NTRS)

Isachsen, Y. W.; Fakundiny, R. H.; Forster, S. W.

1974-01-01

Linear anomalies dominate the new geological information derived from ERTS-1 imagery, total lengths now exceeding 6000 km. Experimentation with a variety of viewing techniques suggests that conventional photogeologic analyses of band 7 results in the location of more than 97 percent of all linears found. The maxima on rose diagrams for ERTS-1 anomalies correspond well with those for mapped faults and topographic lineaments, despite a difference in relative magnitudes of maxima thought due to solar illumination direction. A multiscale analysis of linears showed that single topographic linears at 1:2,500,000 became segmented at 1:1,000,000, aligned zones of shorter parallel, en echelon, or conjugate linears at 1:500,000, and still shorter linears lacking obvious alignment at 1:250,000. Visible glacial features include individual drumlins, best seen in winter imagery, drumlinoids, eskers, ice-marginal drainage channels, glacial lake shorelines and sand plains, and end moraines.

Geologic Map of the Meskhent Tessera Quadrangle (V-3), Venus: Evidence for Early Formation and Preservation of Regional Topography

NASA Technical Reports Server (NTRS)

Ivanov, M. A.; Head, James W.

2008-01-01

The area of the Meskhent Tessera quadrangle (V-3, 50-75degN, 60-120degE, Fig. 1) corresponds to a transition zone from the uplands of Ishtar Terra to the west to the lowlands of Atalanta Planitia to the east. The topographic configuration, gravity signature, and presence of large tesserae in Ishtar Terra are consistent with extensive areas of thickened crust and tectonically stabilized lithosphere representing ancient and now extinct regimes of mantle convection. The gravity and topographic characteristics of Atalanta Planitia have been cited as evidence for large-scale mantle downwelling. Thus, the region of Meskhent Tessera quadrangle represents an important sample for the study of the regional history of long-wavelength topography (highlands, midlands, and lowlands), interaction between the downwelling and areas of thickened crust/lithosphere, formation of associated tectonic features, and emplacement of volcanic plains.

Topographic Ceres Map With Crater Names

NASA Image and Video Library

2015-07-28

This color-coded map from NASA Dawn mission shows the highs and lows of topography on the surface of dwarf planet Ceres. It is labeled with names of features approved by the International Astronomical Union. Occator, the mysterious crater containing Ceres' mysterious bright spots, is named after the Roman agriculture deity of harrowing, a method of leveling soil. They retain their bright appearance in this map, although they are color-coded in the same green elevation of the crater floor in which they sit. The color scale extends about 5 miles (7.5 kilometers) below the surface in indigo to 5 miles (7.5 kilometers) above the surface in white. The topographic map was constructed from analyzing images from Dawn's framing camera taken from varying sun and viewing angles. The map was combined with an image mosaic of Ceres and projected as an simple cylindrical projection. http://photojournal.jpl.nasa.gov/catalog/PIA19606

Synthesis, Characterization, Topographical Modification, and Surface Properties of Copoly(Imide Siloxane)s

NASA Technical Reports Server (NTRS)

Wohl, Christopher J.; Atkins, Brad M.; Belcher, Marcus A.; Connell, John W.

2012-01-01

Novel copoly(imide siloxane)s were synthesized from commercially available aminopropyl terminated siloxane oligomers, aromatic dianhydrides, and diamines. This synthetic approach produced copolymers with well-defined siloxane blocks linked with imide units in a random fashion. The copoly(amide acid)s were characterized by solution viscosity and subsequently used to cast thin films followed by thermal imidization in an inert atmosphere. Thin films were characterized using contact angle goniometry, attenuated total reflection Fourier transform infrared spectroscopy, confocal and optical microscopy, and tensile testing. Adhesion of micronsized particles was determined quantitatively using a sonication device. The polydimethylsiloxane (PDMS) moieties lowered the copolymer surface energy due to migration of siloxane moieties to the film s surface, resulting in a notable reduction in particle adhesion. A further reduction in particle adhesion was achieved by introducing topographical features on a scale of several to tens of microns by a laser ablation technique.

Topographic Features of Malyy Naryn River Watershed Based on Different Data

NASA Astrophysics Data System (ADS)

Li, M.; Chen, L.; Cui, Y.; Zhang, M.

2018-04-01

This paper researched the influence on the topographical characteristics of watersheds by setting different catchment area thresholds based on different data sets, namely ZY3 DSM, SRTM DEM and ASTER GDEM. Slope, hypsometric integral, river network density and river network discrepancy are analyzed and compared. The results are as follows: a) Three data sets all can express the same rough terrain characteristics and the same degree of watershed topography development; b) ZY3 DSM can reflect terrain information over the Malyy Naryn River watershed in most detail and it has the best expression effect on the terrain among the three data sets of ZY3 DSM, SRTM DEM and ASTER GDEM, followed by SRTM DEM, and the effect of ASTER GDEM is the worst; c) The similarity of river networks extracted by ZY3 DSM and SRTM DEM is the highest, and the similarity between ZY3 DSM and ASTER GDEM is the lowest one.

Topography of the Overriding Plate During Progressive Subduction: A Dynamic Model to Explain Forearc Subsidence

NASA Astrophysics Data System (ADS)

Chen, Zhihao; Schellart, Wouter P.; Duarte, João. C.; Strak, Vincent

2017-10-01

Overriding plate topography provides constraints on subduction zone geodynamics. We investigate its evolution using fully dynamic laboratory models of subduction with techniques of stereoscopic photogrammetry and particle image velocimetry. Model results show that the topography is characterized by an area of forearc dynamic subsidence, with a magnitude scaling to 1.44-3.97 km in nature, and a local topographic high between the forearc subsided region and the trench. These topographic features rapidly develop during the slab free-sinking phase and gradually decrease during the steady state slab rollback phase. We propose that they result from the variation of the vertical component of the trench suction force along the subduction zone interface, which gradually increases with depth and results from the gradual slab steepening during the initial transient slab sinking phase. The downward mantle flow in the nose of the mantle wedge plays a minor role in driving forearc subsidence.

Leaf cuticle topography retrieved by using fringe projection

NASA Astrophysics Data System (ADS)

Martínez, Amalia; Rayas, J. A.; Cordero, Raúl R.; Balieiro, Daniela; Labbe, Fernando

2012-02-01

The combination (often referred to as phase-stepping profilometry, PSP) of the fringe projection technique and the phase-stepping method allowed us to retrieve topographic maps of cuticles isolated from the abaxial surface of leaves; these were in turn sampled from an apple tree ( Malus domestica) of the variety Golden Delicious. The topographic maps enabled us to assess the natural features on the illuminated surface and also to detect the whole-field spatial variations in the thickness of the cuticle. Most of our attention was paid to retrieve the highly-resolved elevation information from the cuticle surface, which included the trace (in the order of tens of micrometers) left by ribs and veins. We expect that the PSP application for retrieving the cuticle topography will facilitate further studies on the dispersion and coverage of state-of-the-art agrochemical compounds meant to improve the defending properties of the cuticle. Methodological details are provided below.

Reassessing the Ancient Martian Ocean Hypothesis using Global Distribution of Valley Networks

NASA Astrophysics Data System (ADS)

Chan, Ngai-Ham; Perron, J. Taylor; Mitrovica, Jerry X.

2016-04-01

We re-examine the connection between true polar wander and the Martian ocean hypothesis. Previous studies have investigated the plausibility of an ancient ocean on Mars by examining the ancient putative sea-level markers on the planet's surface. One such study has argued that topographic benches, or contacts, are ancient shorelines, and that these contacts display long-wavelength topographic variations consistent with post-depositional true polar wander (Perron et al., Nature, 2007). In contrast, a second study has argued that the topography of ancient deltaic deposits associated with an ocean on early Mars are not consistent with the true polar wander scenario (Achille & Hynek, Nature Geosci., 2010). We revisit this issue by examining another marker of ancient shorelines --- the fluvial valley networks observed on the surface of Mars. Our results provide further evidence that a true polar wander event drove significant post-depositional deflection of surface features related to an ancient Martian ocean.

Reassessing the Ancient Martian Ocean Hypothesis using Global Distribution of Valley Networks

NASA Astrophysics Data System (ADS)

Chan, N. H.; Perron, J. T.; Mitrovica, J. X.

2015-12-01

We re-examine the connection between true polar wander and the Martian ocean hypothesis. Previous studies have investigated the plausibility of an ancient ocean on Mars by examining the topography of ancient putative sea-level markers on the planet's surface. A previous study has argued that topographic benches, or contacts, are ancient shorelines, and that these contacts display long-wavelength topographic variations consistent with post-depositional true polar wander (Perron et al., Nature, 2007). In contrast, a second study has argued that the topography of ancient deltaic deposits associated with an ocean on early Mars are not consistent with the true polar wander scenario (Achille & Hynek, Nature Geosci., 2010). We revisit this issue by examining another marker of ancient shorelines --- the fluvial valley networks observed on the surface of Mars. Our results provide further evidence that a true polar wander event drove significant post-depositional deflection of surface features related to an ancient Martian ocean.

Water soluble cations and the fluvial history of Mars

NASA Technical Reports Server (NTRS)

Silverman, M. P.; Munoz, E. F.

1975-01-01

The electrical conductivity and water soluble Na, K, Ca, and Mg of aqueous solutions of terrestrial soils and finely divided igneous and metamorphic rocks were determined. Soils from dry terrestrial basins with a history of water accumulation as well as soils from the topographic lows of valleys accumulated water soluble cations, particularly Na and Ca. These soils as a group can be distinguished from the rocks or a second group of soils (leached upland soils and soils from sites other than the topographic lows of valleys) by significant differences in their mean electrical conductivity and water-soluble Na + Ca content. Similar measurements on multiple samples from the surface of Mars, collected by an automated long-range roving vehicle along a highlands-to-basin transect at sites with morphological features resembling dry riverlike channels, are suggested to determine the fluvial history of the planet.

Photometric stereo endoscopy.

PubMed

Parot, Vicente; Lim, Daryl; González, Germán; Traverso, Giovanni; Nishioka, Norman S; Vakoc, Benjamin J; Durr, Nicholas J

2013-07-01

While color video endoscopy has enabled wide-field examination of the gastrointestinal tract, it often misses or incorrectly classifies lesions. Many of these missed lesions exhibit characteristic three-dimensional surface topographies. An endoscopic system that adds topographical measurements to conventional color imagery could therefore increase lesion detection and improve classification accuracy. We introduce photometric stereo endoscopy (PSE), a technique which allows high spatial frequency components of surface topography to be acquired simultaneously with conventional two-dimensional color imagery. We implement this technique in an endoscopic form factor and demonstrate that it can acquire the topography of small features with complex geometries and heterogeneous optical properties. PSE imaging of ex vivo human gastrointestinal tissue shows that surface topography measurements enable differentiation of abnormal shapes from surrounding normal tissue. Together, these results confirm that the topographical measurements can be obtained with relatively simple hardware in an endoscopic form factor, and suggest the potential of PSE to improve lesion detection and classification in gastrointestinal imaging.

Simulation Based Exploration of Critical Zone Dynamics in Intensively Managed Landscapes

NASA Astrophysics Data System (ADS)

Kumar, P.

2017-12-01

The advent of high-resolution measurements of topographic and (vertical) vegetation features using areal LiDAR are enabling us to resolve micro-scale ( 1m) landscape structural characteristics over large areas. Availability of hyperspectral measurements is further augmenting these LiDAR data by enabling the biogeochemical characterization of vegetation and soils at unprecedented spatial resolutions ( 1-10m). Such data have opened up novel opportunities for modeling Critical Zone processes and exploring questions that were not possible before. We show how an integrated 3-D model at 1m grid resolution can enable us to resolve micro-topographic and ecological dynamics and their control on hydrologic and biogeochemical processes over large areas. We address the computational challenge of such detailed modeling by exploiting hybrid CPU and GPU computing technologies. We show results of moisture, biogeochemical, and vegetation dynamics from studies in the Critical Zone Observatory for Intensively managed Landscapes (IMLCZO) in the Midwestern United States.

Morphological similarity and ecological overlap in two rotifer species.

PubMed

Gabaldón, Carmen; Montero-Pau, Javier; Serra, Manuel; Carmona, María José

2013-01-01

Co-occurrence of cryptic species raises theoretically relevant questions regarding their coexistence and ecological similarity. Given their great morphological similitude and close phylogenetic relationship (i.e., niche retention), these species will have similar ecological requirements and are expected to have strong competitive interactions. This raises the problem of finding the mechanisms that may explain the coexistence of cryptic species and challenges the conventional view of coexistence based on niche differentiation. The cryptic species complex of the rotifer Brachionus plicatilis is an excellent model to study these questions and to test hypotheses regarding ecological differentiation. Rotifer species within this complex are filtering zooplankters commonly found inhabiting the same ponds across the Iberian Peninsula and exhibit an extremely similar morphology-some of them being even virtually identical. Here, we explore whether subtle differences in body size and morphology translate into ecological differentiation by comparing two extremely morphologically similar species belonging to this complex: B. plicatilis and B. manjavacas. We focus on three key ecological features related to body size: (1) functional response, expressed by clearance rates; (2) tolerance to starvation, measured by growth and reproduction; and (3) vulnerability to copepod predation, measured by the number of preyed upon neonates. No major differences between B. plicatilis and B. manjavacas were found in the response to these features. Our results demonstrate the existence of a substantial niche overlap, suggesting that the subtle size differences between these two cryptic species are not sufficient to explain their coexistence. This lack of evidence for ecological differentiation in the studied biotic niche features is in agreement with the phylogenetic limiting similarity hypothesis but requires a mechanistic explanation of the coexistence of these species not based on differentiation related to biotic niche axes.

Systemic lupus erythematosus-associated neutrophilic dermatosis--an underrecognized neutrophilic dermatosis in patients with systemic lupus erythematosus.

PubMed

Larson, Allison R; Granter, Scott R

2014-03-01

Neutrophilic dermatoses are an uncommon manifestation of lupus. We describe the clinical and histopathologic features of 14 patients with systemic lupus erythematosus (SLE) and neutrophilic dermatoses, 2 of whom had no prior history of SLE. Thirteen patients were female, ranging in age from 27 to 62 years (mean age, 42.8 years). One patient was a 20-year-old man. Most lesions were described as erythematous papules and plaques and showed annular morphology in 6 patients and a photodistribution in 2 patients. Histopathologic examination in all cases showed an interstitial neutrophilic infiltrate with leukocytoclasis that ranged from sparse in 5 cases and moderate to dense in 9 cases. With one exception, those cases with moderate to dense infiltrates resembled Sweet's syndrome at scanning magnification. Two cases resembled bullous SLE, and 1 case showed overlapping features of bullous SLE and Sweet's syndrome. Interface changes were seen in 8 patients, which were subtle and vacuolar in 7. One case was associated with a florid interface tissue reaction. Dermal mucin was seen in 4 cases and was a prominent feature in only one of these. One case showed a minute discrete focus resembling palisaded neutrophilic and granulomatous dermatitis. It is important to consider SLE-associated neutrophilic dermatosis in the differential diagnosis of neutrophilic tissue reactions particularly because some patients will have no prior history of lupus. It is also important to be aware of the broad histologic spectrum that may be encountered in SLE-associated neutrophilic dermatosis, ranging from subtle paucicellular lesions to florid Sweet's-like lesions associated with a dense neutrophilic infiltrate. Copyright © 2014 Elsevier Inc. All rights reserved.

Neural Measures Reveal Implicit Learning during Language Processing.

PubMed

Batterink, Laura J; Cheng, Larry Y; Paller, Ken A

2016-10-01

Language input is highly variable; phonological, lexical, and syntactic features vary systematically across different speakers, geographic regions, and social contexts. Previous evidence shows that language users are sensitive to these contextual changes and that they can rapidly adapt to local regularities. For example, listeners quickly adjust to accented speech, facilitating comprehension. It has been proposed that this type of adaptation is a form of implicit learning. This study examined a similar type of adaptation, syntactic adaptation, to address two issues: (1) whether language comprehenders are sensitive to a subtle probabilistic contingency between an extraneous feature (font color) and syntactic structure and (2) whether this sensitivity should be attributed to implicit learning. Participants read a large set of sentences, 40% of which were garden-path sentences containing temporary syntactic ambiguities. Critically, but unbeknownst to participants, font color probabilistically predicted the presence of a garden-path structure, with 75% of garden-path sentences (and 25% of normative sentences) appearing in a given font color. ERPs were recorded during sentence processing. Almost all participants indicated no conscious awareness of the relationship between font color and sentence structure. Nonetheless, after sufficient time to learn this relationship, ERPs time-locked to the point of syntactic ambiguity resolution in garden-path sentences differed significantly as a function of font color. End-of-sentence grammaticality judgments were also influenced by font color, suggesting that a match between font color and sentence structure increased processing fluency. Overall, these findings indicate that participants can implicitly detect subtle co-occurrences between physical features of sentences and abstract, syntactic properties, supporting the notion that implicit learning mechanisms are generally operative during online language processing.

Morphological Similarity and Ecological Overlap in Two Rotifer Species

PubMed Central

Gabaldón, Carmen; Montero-Pau, Javier; Serra, Manuel; Carmona, María José

2013-01-01

Co-occurrence of cryptic species raises theoretically relevant questions regarding their coexistence and ecological similarity. Given their great morphological similitude and close phylogenetic relationship (i.e., niche retention), these species will have similar ecological requirements and are expected to have strong competitive interactions. This raises the problem of finding the mechanisms that may explain the coexistence of cryptic species and challenges the conventional view of coexistence based on niche differentiation. The cryptic species complex of the rotifer Brachionus plicatilis is an excellent model to study these questions and to test hypotheses regarding ecological differentiation. Rotifer species within this complex are filtering zooplankters commonly found inhabiting the same ponds across the Iberian Peninsula and exhibit an extremely similar morphology—some of them being even virtually identical. Here, we explore whether subtle differences in body size and morphology translate into ecological differentiation by comparing two extremely morphologically similar species belonging to this complex: B. plicatilis and B. manjavacas. We focus on three key ecological features related to body size: (1) functional response, expressed by clearance rates; (2) tolerance to starvation, measured by growth and reproduction; and (3) vulnerability to copepod predation, measured by the number of preyed upon neonates. No major differences between B. plicatilis and B. manjavacas were found in the response to these features. Our results demonstrate the existence of a substantial niche overlap, suggesting that the subtle size differences between these two cryptic species are not sufficient to explain their coexistence. This lack of evidence for ecological differentiation in the studied biotic niche features is in agreement with the phylogenetic limiting similarity hypothesis but requires a mechanistic explanation of the coexistence of these species not based on differentiation related to biotic niche axes. PMID:23451154

Extension and gold mineralisation in the hanging walls of active convergent continental shear zones

NASA Astrophysics Data System (ADS)

Upton, Phaedra; Craw, Dave

2014-07-01

Orogenic gold-bearing quartz veins form in mountain belts adjacent to convergent tectonic boundaries. The vein systems, hosted in extensional structures within compressively deformed rocks, are a widespread feature of these orogens. In many cases the extensional structures that host gold-bearing veins have been superimposed on, and locally controlled by, compressional structures formed within the convergent orogen. Exploring these observations within the context of a three-dimensional mechanical model allows prediction of mechanisms and locations of extensional zones within convergent orogens. Our models explore the effect of convergence angle and mid-crustal strength on stress states and compare them to the Southern Alps and Taiwan. The dilatation zones coincide with the highest mountains, in the hanging walls of major plate boundary faults, and can extend as deep as the brittle-ductile transition. Extensional deformation is favoured in the topographic divide region of oblique orogens with mid-lower crustal rheology that promotes localisation rather than diffuse deformation. In the near surface, topography influences the stress state to a depth approximately equal to the topographic relief, bringing the rock closer to failure and rotating σ1 to near vertical. The distribution of gold-bearing extensional veins may indicate the general position of the topographic divide within exhumed ancient orogens.

Development of new mapping standards for geological surveys in Greenland

NASA Astrophysics Data System (ADS)

Mätzler, Eva; langley, Kirsty; Hollis, Julie; Heide-Jørgensen, Helene

2017-04-01

The current official topographic and geological maps of Greenland are in scale of 1:250:000 and 1:500.000 respectively, allowing only very limited amount of detail. The maps are outdated, and periglacial landscapes have changed significantly since the acquisition date. Hence, new affordable mapping products of high quality are in demand that can be available within a restricted time frame. In order to fulfill those demands a new mapping standard based on satellite imagery was developed, where classifications are mainly carried out with algorithms suitable for automatization. A Digital Elevation Model (ArcticDEM) was applied allowing examination of topographic and geological structures and 3D visualizing. Information on topographic features and lithology was extracted based on analysis of spectral characteristics from different multispectral data sources (Landsat 8, ASTER, WorldView-3) partly combined with the DEM. A first product is completed, and validation was carried out by field surveys. Field and remotely sensed data were integrated into a GIS database, and derived data will be freely available providing a valuable tool for planning and carrying out mineral exploration and other field activities. This study offers a method for generating up-to-date, low-cost and high quality mapping products suitable for Arctic regions, where accessibility is restricted due to remoteness and lack of infrastructure.

Ground motion in the presence of complex topography: Earthquake and ambient noise sources

USGS Publications Warehouse

Hartzell, Stephen; Meremonte, Mark; Ramírez-Guzmán, Leonardo; McNamara, Daniel

2014-01-01

To study the influence of topography on ground motion, eight seismic recorders were deployed for a period of one year over Poverty Ridge on the east side of the San Francisco Bay Area, California. This location is desirable because of its proximity to local earthquake sources and the significant topographic relief of the array (439 m). Topographic amplification is evaluated as a function of frequency using a variety of methods, including reference‐site‐based spectral ratios and single‐station horizontal‐to‐vertical spectral ratios using both shear waves from earthquakes and ambient noise. Field observations are compared with the predicted ground motion from an accurate digital model of the topography and a 3D local velocity model. Amplification factors from the theoretical calculations are consistent with observations. The fundamental resonance of the ridge is prominently observed in the spectra of data and synthetics; however, higher‐frequency peaks are also seen primarily for sources in line with the major axis of the ridge, perhaps indicating higher resonant modes. Excitations of lateral ribs off of the main ridge are also seen at frequencies consistent with their dimensions. The favored directions of resonance are shown to be transverse to the major axes of the topographic features.

Demonstration of LiDAR and Orthophotography for Wide Area Assessment at Pueblo Precision Bombing Range #2 Colorado and Borrego Military Wash Area, California

DTIC Science & Technology

2008-12-01

Circular Aiming Point Target Features for BT64 at Borrego Shown on Color Orthophoto ...23 Figure 7. Extracted Railroad Strafing Target at Borrego Shown on the Color Orthophoto ....... 23 iv...topographic maps has developed only within the last 7 to 10 years. Orthophoto imagery was first produced more than over 30 years ago and was first

Earth Resources. A Continuing Bibliography with Indexes

DTIC Science & Technology

1987-11-01

Airborne microwave Doppler measurements of ocean of Guinea according to ground-based and satellite Coral reef remote sensing applications wave directional...understanding of internal Coral reef remote sensing applications an earth-to-satellite Hadamard transform laser long-path waves in the ocean p 20 A87-32951...classifications of coral reefs , and an are provided and new topographic features that are revealed are autocorrelation technique is being developed to

STS-30 Magellan spacecraft processing at Kennedy Space Center (KSC) SAEF-2

NASA Image and Video Library

1988-10-08

S89-25281 (8 Oct 1988) --- The Magellan spacecraft is hoisted from the transport trailer of the Payload Environmental Transportation System (PETS) to the floor of the cleanroom in the SAEF-2 planetary checkout facility at the Kennedy Space Center (KSC). The spacecraft, destined for unprecedented studies of Venusian topographic features, is to be deployed by the crew of NASA's STS-30 mission in April 1989.

Methods of Determining Playa Surface Conditions Using Remote Sensing

DTIC Science & Technology

1987-10-08

NO. 11. TITLE (include Security Classification) METHODS OF DETERMINING PLAYA SURFACE CONDITIONS USING REMOTE SENSING 12. PERSONAL AUTHOR(S) J. PONDER...PLAYA SURFACE CONDITIONS USING REMOTE SENSING J. Ponder Henley U. S. Army Engineer Topographic Laboratories Fort Belvoir, Virginia 22060-5546 "ABSTRACT...geochemistry, hydrology and remote sensing but all of these are important to the understanding of these unique geomorphic features. There is a large body

Realization of State-Space Models for Wave Propagation Simulations

DTIC Science & Technology

2012-01-01

reduction techniques can be applied to reduce the dimension of the model further if warranted. INFRASONIC PROPAGATION MODEL Infrasound is sound below 20...capable of scatter- ing and blocking the propagation. This is because the infrasound wavelengths are near the scales of topographic features. These...and Development Center (ERDC) Big Black Test Site (BBTS) and an infrasound -sensing array at the ERDC Waterways Experiment Station (WES). Both are

Enhancing hydrologic mapping using LIDAR and high resolution aerial photos on the Frances Marion National Forest in coastal South Carolina

Treesearch

Andy Maceyka; William F. Hansen

2016-01-01

Evaluating hydrology within coastal marine terrace features has always been problematic as watershed boundaries and stream detail are difficult to determine in low gradient terrain with dense bottomland forests. Various studies have improved hydrologic detail using USGS Topographic Contour Maps (Hansen 2001, Eidson and others 2005) or Light Detection and Ranging (LIDAR...

General fusion approaches for the age determination of latent fingerprint traces: results for 2D and 3D binary pixel feature fusion

NASA Astrophysics Data System (ADS)

Merkel, Ronny; Gruhn, Stefan; Dittmann, Jana; Vielhauer, Claus; Bräutigam, Anja

2012-03-01

Determining the age of latent fingerprint traces found at crime scenes is an unresolved research issue since decades. Solving this issue could provide criminal investigators with the specific time a fingerprint trace was left on a surface, and therefore would enable them to link potential suspects to the time a crime took place as well as to reconstruct the sequence of events or eliminate irrelevant fingerprints to ensure privacy constraints. Transferring imaging techniques from different application areas, such as 3D image acquisition, surface measurement and chemical analysis to the domain of lifting latent biometric fingerprint traces is an upcoming trend in forensics. Such non-destructive sensor devices might help to solve the challenge of determining the age of a latent fingerprint trace, since it provides the opportunity to create time series and process them using pattern recognition techniques and statistical methods on digitized 2D, 3D and chemical data, rather than classical, contact-based capturing techniques, which alter the fingerprint trace and therefore make continuous scans impossible. In prior work, we have suggested to use a feature called binary pixel, which is a novel approach in the working field of fingerprint age determination. The feature uses a Chromatic White Light (CWL) image sensor to continuously scan a fingerprint trace over time and retrieves a characteristic logarithmic aging tendency for 2D-intensity as well as 3D-topographic images from the sensor. In this paper, we propose to combine such two characteristic aging features with other 2D and 3D features from the domains of surface measurement, microscopy, photography and spectroscopy, to achieve an increase in accuracy and reliability of a potential future age determination scheme. Discussing the feasibility of such variety of sensor devices and possible aging features, we propose a general fusion approach, which might combine promising features to a joint age determination scheme in future. We furthermore demonstrate the feasibility of the introduced approach by exemplary fusing the binary pixel features based on 2D-intensity and 3D-topographic images of the mentioned CWL sensor. We conclude that a formula based age determination approach requires very precise image data, which cannot be achieved at the moment, whereas a machine learning based classification approach seems to be feasible, if an adequate amount of features can be provided.

Erosion-tectonics feedbacks in shaping the landscape: An example from the Mekele Outlier (Tigray, Ethiopia)

NASA Astrophysics Data System (ADS)

Sembroni, Andrea; Molin, Paola; Dramis, Francesco; Faccenna, Claudio; Abebe, Bekele

2017-05-01

An outlier consists of an area of younger rocks surrounded by older ones. Its formation is mainly related to the erosion of surrounding rocks which causes the interruption of the original continuity of the rocks. Because of its origin, an outlier is an important witness of the paleogeography of a region and, therefore, essential to understand its topographic and geological evolution. The Mekele Outlier (N Ethiopia) is characterized by poorly incised Mesozoic marine sediments and dolerites (∼2000 m in elevation), surrounded by strongly eroded Precambrian and Paleozoic rocks and Tertiary volcanic deposits in a context of a mantle supported topography. In the past, studies about the Mekele outlier focused mainly in the mere description of the stratigraphic and tectonic settings without taking into account the feedback between surface and deep processes in shaping such peculiar feature. In this study we present the geological and geomorphometric analyses of the Mekele Outlier taking into account the general topographic features (slope map, swath profiles, local relief), the river network and the principal tectonic lineaments of the outlier. The results trace the evolution of the study area as related not only to the mere erosion of the surrounding rocks but to a complex interaction between surface and deep processes where the lithology played a crucial role.

A comparative evaluation of supervised and unsupervised representation learning approaches for anaplastic medulloblastoma differentiation

NASA Astrophysics Data System (ADS)

Cruz-Roa, Angel; Arevalo, John; Basavanhally, Ajay; Madabhushi, Anant; González, Fabio

2015-01-01

Learning data representations directly from the data itself is an approach that has shown great success in different pattern recognition problems, outperforming state-of-the-art feature extraction schemes for different tasks in computer vision, speech recognition and natural language processing. Representation learning applies unsupervised and supervised machine learning methods to large amounts of data to find building-blocks that better represent the information in it. Digitized histopathology images represents a very good testbed for representation learning since it involves large amounts of high complex, visual data. This paper presents a comparative evaluation of different supervised and unsupervised representation learning architectures to specifically address open questions on what type of learning architectures (deep or shallow), type of learning (unsupervised or supervised) is optimal. In this paper we limit ourselves to addressing these questions in the context of distinguishing between anaplastic and non-anaplastic medulloblastomas from routine haematoxylin and eosin stained images. The unsupervised approaches evaluated were sparse autoencoders and topographic reconstruct independent component analysis, and the supervised approach was convolutional neural networks. Experimental results show that shallow architectures with more neurons are better than deeper architectures without taking into account local space invariances and that topographic constraints provide useful invariant features in scale and rotations for efficient tumor differentiation.

Influence of the State of the Tungsten Tip on STM Topographic Images of SnSe Surfaces

NASA Astrophysics Data System (ADS)

Ly, Trinh Thi; Kim, Jungdae

2018-03-01

Tin selenide (SnSe) has recently attracted significant attention because of its excellent thermoelectric properties with a figure of merit (ZT) of 2.6. Previous scanning tunneling microscopy (STM) studies of SnSe surfaces showed that only Sn atoms are resolved in topographic images due to the dominant contribution of the Sn 5 p z states in tunneling. However, when the state of the tungsten (W) tip changes from a typical four-lobe d state such as d xy or {d_{{x^2} - {y^2}}} to a two-lobe {d_{{z^2}}} state, the atomic features observed on the SnSe surface in STM topography can be dramatically altered. In this report, we present the results of a systematic study on the influence of the W tip's states on the STM images of SnSe surfaces. Sn atoms are observed with much stronger corrugation amplitude and smaller apparent radius when the tip is in a {d_{{z^2}}} state. In addition, the atomic features of the Se atoms become visible because of the sharply focused shape of the W {d_{{z^2}}} state. We expect our results to provide important information for establishing a better understanding of the microscopic nature of SnSe surfaces.

Bank gully extraction from DEMs utilizing the geomorphologic features of a loess hilly area in China

NASA Astrophysics Data System (ADS)

Yang, Xin; Na, Jiaming; Tang, Guoan; Wang, Tingting; Zhu, Axing

2018-04-01

As one of most active gully types in the Chinese Loess Plateau, bank gullies generally indicate soil loss and land degradation. This study addressed the lack of detailed, large scale monitoring of bank gullies and proposed a semi-automatic method for extracting bank gullies, given typical topographic features based on 5 m resolution DEMs. First, channel networks, including bank gullies, are extracted through an iterative channel burn-in algorithm. Second, gully heads are correctly positioned based on the spatial relationship between gully heads and their corresponding gully shoulder lines. Third, bank gullies are distinguished from other gullies using the newly proposed topographic measurement of "relative gully depth (RGD)." The experimental results from the loess hilly area of the Linjiajian watershed in the Chinese Loess Plateau show that the producer accuracy reaches 87.5%. The accuracy is affected by the DEM resolution and RGD parameters, as well as the accuracy of the gully shoulder line. The application in the Madigou watershed with a high DEM resolution validated the duplicability of this method in other areas. The overall performance shows that bank gullies can be extracted with acceptable accuracy over a large area, which provides essential information for research on soil erosion, geomorphology, and environmental ecology.

Climatology and variability of SST frontal activity in Eastern Pacific Ocean over the past decade

NASA Astrophysics Data System (ADS)

Wang, Y.; Yuan, Y.

2016-12-01

Distribution of sea surface temperature (SST) fronts are derived from high-resolution MODIS dataset in Eastern Pacific Ocean from 2003 to 2015. Daily distribution of frontal activities shows detailed feature and movement of front and the discontinuity of the track of front cause by cloud coverage. Monthly frontal probability is calculated to investigate corresponding climatology and variability. Frontal probability is generally higher along the coast and decreasing offshore. The frontal activity could extend few hundreds of kilometers near the major capes and central Pacific Ocean. SST gradient associated with front is changing over different latitude with stronger gradient near the mid-latitude and under major topographic effects near tropics. Corresponding results from empirical orthogonal functions (EOF) shows major variability of SST front is found in mid-latitude and central Pacific Ocean. The temporal variability captures a strong interannual and annual variability in those regions, while Intraannual variability are found more important at small scale near major capes and topographic features. The frontal variability is highly impacted by wind stress, upwelling, air-sea interaction, current, topography, eddy activity, El Nino along with other factors. And front plays an importance role in influencing the distribution of nutrients, the activity of fisheries and the development of ecosystems.

Texture sensing of cytoskeletal dynamics in cell migration

NASA Astrophysics Data System (ADS)

Das, Satarupa; Lee, Rachel; Hourwitz, Matthew J.; Sun, Xiaoyu; Parent, Carole; Fourkas, John T.; Losert, Wolfgang

Migrating cells can be directed towards a target by gradients in properties such as chemical concentration or mechanical properties of the surrounding microenvironment. In previous studies we have shown that micro/nanotopographical features on scales comparable to those of natural collagen fibers can guide fast migrating amoeboid cells by aligning actin polymerization waves to such nanostructures. We find that actin microfilaments and microtubules are aligned along the nanoridge topographies, modulating overall cell polarity and directional migration in epithelial cells. This work shows that topographic features on a biologically relevant length scale can modulate migration outcomes by affecting the texture sensing property of the cytoskeleton.

DESDynI Lidar for Solid Earth Applications

NASA Technical Reports Server (NTRS)

Sauber, Jeanne; Hofton, Michelle; Bruhn, Ronald; Lutchke, Scott; Blair, Bryan

2011-01-01

As part of the NASA's DESDynI mission, global elevation profiles from contiguous 25 m footprint Lidar measurements will be made. Here we present results of a performance simulation of a single pass of the multi-beam Lidar instrument over uplifted marine terraces in southern Alaska. The significance of the Lidar simulations is that surface topography would be captured at sufficient resolution for mapping uplifted terraces features but it will be hard to discern I-2m topographic change over features less than tens of meters in width. Since Lidar would penetrate most vegetation, the accurate bald Earth elevation profiles will give new elevation information beyond the standard 30-m OEM.

Superpixel-Augmented Endmember Detection for Hyperspectral Images

NASA Technical Reports Server (NTRS)

Thompson, David R.; Castano, Rebecca; Gilmore, Martha

2011-01-01

Superpixels are homogeneous image regions comprised of several contiguous pixels. They are produced by shattering the image into contiguous, homogeneous regions that each cover between 20 and 100 image pixels. The segmentation aims for a many-to-one mapping from superpixels to image features; each image feature could contain several superpixels, but each superpixel occupies no more than one image feature. This conservative segmentation is relatively easy to automate in a robust fashion. Superpixel processing is related to the more general idea of improving hyperspectral analysis through spatial constraints, which can recognize subtle features at or below the level of noise by exploiting the fact that their spectral signatures are found in neighboring pixels. Recent work has explored spatial constraints for endmember extraction, showing significant advantages over techniques that ignore pixels relative positions. Methods such as AMEE (automated morphological endmember extraction) express spatial influence using fixed isometric relationships a local square window or Euclidean distance in pixel coordinates. In other words, two pixels covariances are based on their spatial proximity, but are independent of their absolute location in the scene. These isometric spatial constraints are most appropriate when spectral variation is smooth and constant over the image. Superpixels are simple to implement, efficient to compute, and are empirically effective. They can be used as a preprocessing step with any desired endmember extraction technique. Superpixels also have a solid theoretical basis in the hyperspectral linear mixing model, making them a principled approach for improving endmember extraction. Unlike existing approaches, superpixels can accommodate non-isometric covariance between image pixels (characteristic of discrete image features separated by step discontinuities). These kinds of image features are common in natural scenes. Analysts can substitute superpixels for image pixels during endmember analysis that leverages the spatial contiguity of scene features to enhance subtle spectral features. Superpixels define populations of image pixels that are independent samples from each image feature, permitting robust estimation of spectral properties, and reducing measurement noise in proportion to the area of the superpixel. This permits improved endmember extraction, and enables automated search for novel and constituent minerals in very noisy, hyperspatial images. This innovation begins with a graph-based segmentation based on the work of Felzenszwalb et al., but then expands their approach to the hyperspectral image domain with a Euclidean distance metric. Then, the mean spectrum of each segment is computed, and the resulting data cloud is used as input into sequential maximum angle convex cone (SMACC) endmember extraction.

Leigh syndrome: MRI findings in two children.

PubMed

Kartikasalwah, Al; Lh, Ngu

2010-01-01

Leigh syndrome is a progressive neurodegenerative disorder of childhood. The symmetrical necrotic lesions in the basal ganglia and/or brainstem which appear as hyperintense lesions on T2-weighted MRI is characteristic and one of the essential diagnostic criteria. Recognising this MR imaging pattern in a child with neurological problems should prompt the clinician to investigate for Leigh syndrome. We present here two cases of Leigh syndrome due to different biochemical/genetic defects, and discuss the subtle differences in their MR neuroimaging features.

Mapping hydrological environments in central Amazonia: ground validation and surface model based on SRTM DEM data corrected for deforestation

NASA Astrophysics Data System (ADS)

Moulatlet, G. M.; Rennó, C. D.; Costa, F. R. C.; Emilio, T.; Schietti, J.

2014-07-01

One of the most important freely available digital elevation models (DEMs) for Amazonia is the one obtained by the Shuttle Radar Topography Mission (SRTM). However, since SRTM tends to represent the vegetation surface instead of the ground surface, the broad use of SRTM DEM as a framework for terrain description in Amazonia is hampered by the presence of deforested areas. We present here two datasets: (1) a deforestation-corrected SRTM DEM for the interfluve between the Purus and Madeira rivers, in central Amazonia, which passed through a careful identification of different environments and has deforestation features corrected by a new method of increasing pixel values of the DEM; and (2) a set of eighteen hydrological-topographic descriptors based on the corrected SRTM DEM. The hydrological-topographic description was generated by the Height Above the Nearest Drainage (HAND) algorithm, which normalizes the terrain elevation (a.s.l.) by the elevation of the nearest hydrologically connected drainage. The validation of the HAND dataset was done by in situ hydrological description of 110 km of walking trails also available in this dataset. The new SRTM DEM expands the applicability of SRTM data for landscape modelling; and the datasets of hydrological features based on topographic modelling is undoubtedly appropriate for ecological modelling and an important contribution for environmental mapping of Amazonia. The deforestation-corrected SRTM DEM is available at http://ppbio.inpa.gov.br/knb/metacat/naman.318.3/ppbio; the polygons selected for deforestation correction are available at http://ppbio.inpa.gov.br/knb/metacat/naman.317.3/ppbio; the set of hydrological-topographic descriptors is available at http://ppbio.inpa.gov.br/knb/metacat/naman.544.2/ppbio; and the environmental description of access trails is available at http://ppbio.inpa.gov.br/knb/metacat/naman.541.2/ppbio.

Topographic and Air-Photo Lineaments in Various Locations Related to Geothermal Exploration in Colorado

DOE Data Explorer

Richard Zehner

2012-02-01

These line shapefiles trace apparent topographic and air-photo lineaments in various counties in Colorado. It was made in order to identify possible fault and fracture systems that might be conduits for geothermal fluids, as part of a DOE reconnaissance geothermal exploration program. Geothermal fluids commonly utilize fault and fractures in competent rocks as conduits for fluid flow. Geothermal exploration involves finding areas of high near-surface temperature gradients, along with a suitable "plumbing system" that can provide the necessary permeability. Geothermal power plants can sometimes be built where temperature and flow rates are high. This line shapefile is an attempt to use desktop GIS to delineate possible faults and fracture orientations and locations in highly prospective areas prior to an initial site visit. Geochemical sampling and geologic mapping could then be centered around these possible faults and fractures. To do this, georeferenced topographic maps and aerial photographs were utilized in an existing GIS, using ESRI ArcMap 10.0 software. The USA_Topo_Maps and World_Imagery map layers were chosen from the GIS Server at server.arcgisonline.com, using a UTM Zone 13 NAD27 projection. This line shapefile was then constructed over that which appeared to be through-going structural lineaments in both the aerial photographs and topographic layers, taking care to avoid manmade features such as roads, fence lines, and utility right-of-ways. Still, it is unknown what actual features these lineaments, if they exist, represent. Although the shapefiles are arranged by county, not all areas within any county have been examined for lineaments. Work was focused on either satellite thermal infrared anomalies, known hot springs or wells, or other evidence of geothermal systems. Finally, lineaments may be displaced somewhat from their actual location, due to such factors as shadow effects with low sun angles in the aerial photographs. Credits: These lineament shapefile was created by Geothermal Development Associates, as part of a geothermal geologic reconnaissance performed by Flint Geothermal, LLC, of Denver Colorado. Use Limitation: These shapefiles were constructed as an aid to geothermal exploration in preparation for a site visit for field checking. We make no claims as to the existence of the lineaments, their location, orientation, and/or nature.

Closed form unsupervised registration of multi-temporal structure from motion-multiview stereo data using non-linearly weighted image features

NASA Astrophysics Data System (ADS)

Seers, T. D.; Hodgetts, D.

2013-12-01

Seers, T. D. & Hodgetts, D. School of Earth, Atmospheric and Environmental Sciences, University of Manchester, UK. M13 9PL. The detection of topological change at the Earth's surface is of considerable scholarly interest, allowing the quantification of the rates of geomorphic processes whilst providing lucid insights into the underlying mechanisms driving landscape evolution. In this regard, the past decade has witnessed the ever increasing proliferation of studies employing multi-temporal topographic data in within the geosciences, bolstered by continuing technical advancements in the acquisition and processing of prerequisite datasets. Provided by workers within the field of Computer Vision, multiview stereo (MVS) dense surface reconstructions, primed by structure-from-motion (SfM) based camera pose estimation represents one such development. Providing a cost effective, operationally efficient data capture medium, the modest requirement of a consumer grade camera for data collection coupled with the minimal user intervention required during post-processing makes SfM-MVS an attractive alternative to terrestrial laser scanners for collecting multi-temporal topographic datasets. However, in similitude to terrestrial scanner derived data, the co-registration of spatially coincident or partially overlapping scans produced by SfM-MVS presents a major technical challenge, particularly in the case of semi non-rigid scenes produced during topographic change detection studies. Moreover, the arbitrary scaling resulting from SfM ambiguity requires that a scale matrix must be estimated during the transformation, introducing further complexity into its formulation. Here, we present a novel, fully unsupervised algorithm which utilises non-linearly weighted image features for the solving the similarity transform (scale, translation rotation) between partially overlapping scans produced by SfM-MVS image processing. With the only initialization condition being partial intersection between input image sets, our method has major advantages over conventional iterative least squares minimization based methods (e.g. Iterative Closest Point variants), acting only on rigid areas of target scenes, being capable of reliably estimating the scaling factor and requiring no incipient estimation of the transformation to initialize (i.e. manual rough alignment). Moreover, because the solution is closed form, convergence is considerably more expedient that most iterative methods. It is hoped that the availability of improved co-registration routines, such as the one presented here, will facilitate the routine collection of multi-temporal topographic datasets by a wider range of geoscience practitioners.

Dispersion of deep-sea hydrothermal vent effluents and larvae by submesoscale and tidal currents

NASA Astrophysics Data System (ADS)

Vic, Clément; Gula, Jonathan; Roullet, Guillaume; Pradillon, Florence

2018-03-01

Deep-sea hydrothermal vents provide sources of geochemical materials that impact the global ocean heat and chemical budgets, and support complex biological communities. Vent effluents and larvae are dispersed and transported long distances by deep ocean currents, but these currents are largely undersampled and little is known about their variability. Submesoscale (0.1-10 km) currents are known to play an important role for the dispersion of biogeochemical materials in the ocean surface layer, but their impact for the dispersion in the deep ocean is unknown. Here, we use a series of nested regional oceanic numerical simulations with increasing resolution (from δx = 6 km to δx = 0.75 km) to investigate the structure and variability of highly-resolved deep currents over the Mid-Atlantic Ridge (MAR) and their role on the dispersion of the Lucky Strike hydrothermal vent effluents and larvae. We shed light on a submesoscale regime of oceanic turbulence over the MAR at 1500 m depth, contrasting with open-ocean - i.e., far from topographic features - regimes of turbulence, dominated by mesoscales. Impacts of submesoscale and tidal currents on larval dispersion and connectivity among vent populations are investigated by releasing neutrally buoyant Lagrangian particles at the Lucky Strike hydrothermal vent. Although the absolute dispersion is overall not sensitive to the model resolution, submesoscale currents are found to significantly increase both the horizontal and vertical relative dispersion of particles at O(1-10) km and O(1-10) days, resulting in an increased mixing of the cloud of particles. A fraction of particles are trapped in submesoscale coherent vortices, which enable transport over long time and distances. Tidal currents and internal tides do not significantly impact the horizontal relative dispersion. However, they roughly double the vertical dispersion. Specifically, particles undergo strong tidally-induced mixing close to rough topographic features, which allows them to rise up in the water column and to cross topographic obstacles. The mesoscale variability controls at first order the connectivity between hydrothermal sites and we do not have long enough simulations to conclude on the connectivity between the different MAR hydrothermal sites. However, our simulations suggest that the connectivity might be increased by submesoscale and tidal currents, which act to spread the cloud of particles and help them cross topographic barriers.