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1

Global Multi-Resolution Topography (GMRT) Synthesis - Version 2.0  

NASA Astrophysics Data System (ADS)

The detailed morphology of the global ocean floor is poorly known, with most areas mapped only at low resolution using satellite-based measurements. Ship-based sonars provide data at resolution sufficient to quantify seafloor features related to the active processes of erosion, sediment flow, volcanism, and faulting. To date, these data have been collected in a small fraction of the global ocean (<10%). The Global Multi-Resolution Topography (GMRT) synthesis makes use of sonar data collected by scientists and institutions worldwide, merging them into a single continuously updated compilation of high-resolution seafloor topography. Several applications, including GeoMapApp (http://www.geomapapp.org) and Virtual Ocean (http://www.virtualocean.org), make use of the GMRT Synthesis and provide direct access to images and underlying gridded data. Source multibeam files included in the compilation can also accessed through custom functionality in GeoMapApp. The GMRT Synthesis began in 1992 as the Ridge Multibeam Synthesis. It was subsequently expanded to include bathymetry data from the Southern Ocean, and now includes data from throughout the global oceans. Our design strategy has been to make data available at the full native resolution of shipboard sonar systems, which historically has been ~100 m in the deep sea (Ryan et al., 2009). A new release of the GMRT Synthesis in Fall of 2010 includes several significant improvements over our initial strategy. In addition to increasing the number of cruises included in the compilation by over 25%, we have developed a new protocol for handling multibeam source data, which has improved the overall quality of the compilation. The new tileset also includes a discrete layer of sonar data in the public domain that are gridded to the full resolution of the sonar system, with data gridded 25 m in some areas. This discrete layer of sonar data has been provided to Google for integration into Google’s default ocean base map. NOAA coastal grids and numerous grids contributed by the international science community are also integrated into the GMRT Synthesis. Finally, terrestrial elevation data from NASA’s ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) global DEM, and the USGS National Elevation Dataset have been included in the synthesis, providing resolution of up to 10 m in some areas of the US.

Ferrini, V.; Coplan, J.; Carbotte, S. M.; Ryan, W. B.; O'Hara, S.; Morton, J. J.

2010-12-01

2

Tools for Automated Quality Assurance of Multibeam Bathymetry Data for the Global Multi-Resolution Topography (GMRT) Synthesis  

NASA Astrophysics Data System (ADS)

The preservation and sharing of oceanographic data collected aboard diverse research cruises throughout the world’s ocean enables the creation of global compilations and syntheses. With an increase in the availability of data comes a need for developing tools and protocols that can be used to rapidly reduce data to produce high quality data products. Quality evaluation and cleaning of bathymetric data are the key components of multibeam data assembly necessary to produce maps and grids of seafloor topography. The intended use for a particular data product largely determines the level of processing, such that no single approach can fully exploit the richness of a particular data set. The Global Multi-Resolution Topography (GMRT) Synthesis is a global compilation of seafloor topography to >100 m resolution that makes use of sonar data in the public domain. A new procedure for routinely handling large volumes of swath bathymetry data for inclusion in version 2.0 of the GMRT Synthesis was developed to ensure overall data quality and rapidly identify and address correctable problems in the data. Data quality assessment (QA) includes the use of automated scripts, manual inspection of data and processing of the files to address problems. The process was designed around the MBSystem (http://www.ldeo.columbia.edu/res/pi/MB-System/) software suite, leverages existing tools to open each multibeam file and extract relevant information, and uses QA criteria based specifically on the needs of the GMRT Synthesis. Parameters that are assessed relate to system settings, navigation, depth values, and sound velocity. The QA process generates a file set summary, and a detailed file-based listing of problems, both of which are intended to inform subsequent manual inspection of data. A custom version of GeoMapApp (www.geomapapp.org) is the primary interface used for inspecting and interacting with the data, providing a rapid means for identifying problems within the context of the GMRT Synthesis. Standard MBSystem tools and protocols are used to address problematic data.

O'Hara, S. H.; Ferrini, V.; Coplan, J.; Morton, J. J.

2010-12-01

3

Global Multi-Resolution Topography synthesis  

NASA Astrophysics Data System (ADS)

Seafloor bathymetric data acquired with modern swath echo sounders provide coverage for only a small fraction of the global seabed yet are of high value for studies of the dynamic processes of seafloor volcanism, tectonics, mass wasting, and sediment transport that create and shape the undersea landscape. A new method for compilation of global seafloor bathymetry that preserves the native resolution of swath sonars is presented. The Global Multi-Resolution Topography synthesis consists of a hierarchy of tiles with digital elevations and shaded relief imagery spanning nine magnification doublings from pole to pole (http://www.marine-geo.org/portals/gmrt). The compilation is updated and accessible as surveys are contributed, edited, and added to the tiles. Access to the bathymetry tiles is via Web services and with WMS-enabled client applications such as GeoMapApp®, Virtual Ocean, NASA World Wind®, and Google Earth®.

Ryan, William B. F.; Carbotte, Suzanne M.; Coplan, Justin O.; O'Hara, Suzanne; Melkonian, Andrew; Arko, Robert; Weissel, Rose Anne; Ferrini, Vicki; Goodwillie, Andrew; Nitsche, Frank; Bonczkowski, Juliet; Zemsky, Richard

2009-03-01

4

Studies of novae at GMRT frequencies  

NASA Astrophysics Data System (ADS)

The Giant Metrewave Radio Telescope (GMRT) which operates at wavelengths longer than 20 cm (frequencies ? 1.4 GHz) has been used to search for radio emission from Galactic novae systems since 2002. Of the 11 Galactic novae observed with GMRT, radio continuum emission has been detected in two of the systems whereas atomic gas associated with two systems has been imaged and studied in the 21 cm signal of H I. The two novae studied in the radio continuum with the GMRT are the remnant of GK Persei, a classical nova which had an outburst in 1901 and RS Ophiuchi, a recurrent nova following its last outburst in 2006. Combining the GMRT data on the classical nova GK Persei with VLA data at earlier epochs resulted in concluding that the nova remnant was undergoing a secular decrease in its flux density and in its adiabatic phase of evolution tep{2005A&A...435..167A}. RS Ophiuchi was observed at 1280, 610, 325 and 240 MHz with the GMRT days after its outburst and detected at all the observed frequencies. The near-simultaneous monitoring of its flux density at the low GMRT frequencies, resulted in the study of its spectral index which was indicative of synchrotron emission at all epochs tep{2007ApJ...667L.171K}. A supernova model resulted in a reasonable fit to the observed light curves; in particular the late appearance of emission at the lower GMRT frequencies due to the foreground clumpy, ionized, thermal circumbinary material. Comparison of these results with the previous outburst indicated that the densities of this clumpy medium had reduced making it optically thin to GMRT frequencies in 2006 tep{2007ApJ...667L.171K}. It is important to complement the higher radio frequency studies with observations at GMRT frequencies since these study different regions and physics of the nova system. Studies at GMRT frequencies can result in insights on the shock physics, distribution and density of the circumbinary material or planetary nebula, magnetic field generation and the spectral index evolution. Since the evolution of a nova system is faster than a supernova and novae are more numerous; these can be studied over shorter timescales. A sensitivity limit of 1 mJy can detect radio emission at GMRT frequencies upto a distance of 10 kpc, if the non-thermal luminosity of the novae system is 10^{13} W Hz^{-1}. Out of the total of about 33 novae detected in the radio bands, 9 have shown the presence of non-thermal emission in their spectra and 4 of these are recurrent in nature. GMRT frequencies are ideal to observe the non-thermal emission from the recurrent nova population as the ejecta expands driving shocks into the dense circumbinary material from the giant companion. An important motivation for studying the non-thermal radio emission from recurrent novae is to interrogate any evolutionary connection to the lack of detectable radio emission from type 1a supernova systems which recurrent novae are believed to evolve into and subsequently lend support to this model.

Kantharia, N. G.

2012-09-01

5

SN2007bg : GMRT Radio observations  

NASA Astrophysics Data System (ADS)

The GMRT observed SN2007bg (Quimby et al. 2007, CBET #927; Prieto et al. GCN #9444; Soderberg A. M., ATel #2066) on 26th June and 1st July 2009 at 610 and 1280 MHz, respectively. The SN was not detected at 610 MHz to a three sigma upper limit of 225 microJy.

Kamble, Atish; Pal, Sabyasachi; Bhattacharya, Dipankar; Wijers, Ralph; Chandra, Ishwara

2009-07-01

6

A software baseband receiver for pulsar astronomy at GMRT  

Microsoft Academic Search

A variety of pulsar studies, ranging from high precision astrometry to tests for theories of gravity, require high time resolution data. Few such observations at more than two frequencies below 1 GHz are available. Giant Meterwave Radio Telescope (GMRT) has the unique capability to provide such multi-frequency pulsar data at low observation frequencies, but the quality and time resolution of

B. C. Joshi; Sunil Ramakrishna

2006-01-01

7

Complete 150MHz GMRT source catalogue (Ghosh+, 2012)  

NASA Astrophysics Data System (ADS)

We have observed in GMRT Time Allocation Committee (GTAC) the fields: * I on 2008-01-08 for 11hrs at 153MHz, center(J2000)=05:30:00+60:00:00 * II on 2010-02-07 for 6hrs at 148MHz, center(J2000)=06:00:00+62:12:58 * III on 2010-02-08 for 6hrs at 148MHz, center(J2000)=12:36:49+62:12:58 * IV on 2005-06-15 for 13hrs at 153MHz, center(J2000)=01:36:48+41:24:23 (1 data file).

Ghosh, A.; Prasad, J.; Bharadwaj, S.; Ali, Sk. S.; Chengalur, J. N.

2013-04-01

8

A software baseband receiver for pulsar astronomy at GMRT  

NASA Astrophysics Data System (ADS)

A variety of pulsar studies, ranging from high precision astrometry to tests for theories of gravity, require high time resolution data. Few such observations at more than two frequencies below 1 GHz are available. Giant Meterwave Radio Telescope (GMRT) has the unique capability to provide such multi-frequency pulsar data at low observation frequencies, but the quality and time resolution of pulsar radio signals is degraded due to dispersion in the interstellar medium at these frequencies. Such degradation is usually taken care of by employing specialized digital hardware, which implement coherent dedispersion algorithm. In recent years, a new alternative is provided by the availability of cheap computer hardware. In this approach, the re- quired signal processing is implemented in software using commercially off-the-shelf available computing hardware. This makes such a receiver flexible and upgradeable unlike a hardware implementation. The salient features and the modes of operation of a high time resolution pulsar instrument for GMRT based on this approach is described in this paper. The capability of the instrument is demonstrated by illustrations of test observations. We have obtained the average profile of PSR B1937+21 at 235 MHz for the first time and this profile indicates a scattering timescale of about 300 µs. Lastly, the possible future extensions of this concept are discussed.

Joshi, B. C.; Ramakrishna, Sunil

2006-12-01

9

GMRT 153MHz (2m) Radio Mini Survey I. (Williams+, 2013)  

NASA Astrophysics Data System (ADS)

The source catalog presented here is derived from seven 4 hour pointings with the GMRT at 153MHz, centered at the NOAO Bootes field. The resulting 30 square degree image has a central noise level of 2mJy/beam and a resolution of 25". (2 data files).

Williams, W. L.; Intema, H. T.; Rottgering, H. J. A.

2012-11-01

10

Search for Radio Emission from Extrasolar Planets: Preliminary Analysis of GMRT Data  

NASA Astrophysics Data System (ADS)

In 2004 we carried out a series of short calibration runs using the central square array of the GMRT. At the operating RF of 150 MHz, we have determined that the GMRT has a fantastic sensitivity of 2 mJy over a bandwidth of 5 MHz and a timescale of one hour and is relatively free of RFI between midnight and early morning hours local time. As part of the calibration runs, we have carried out brief observation of UpsAnd with various observing strategies. In early 2005, we were granted observing time on the GMRT during its Cycle 7 observation period. Our focus to date has been in characterizing the large scale structure of the dynamic spectra, identifying RFI and developing filters to remove them. We will present our results from both the short calibrations runs of 2004 as well as those obtained from the 2005 observations. We will also describe techniques for detection of chirps as present in Jupiter observations, including match filter strategies. In addition we will describe some preliminary results for detecting bursts via statistical techniques. We plan to use Jupiter and Saturn data to calibrate our detection efficiency for various strategies. We will also discuss our software package for data analysis and computing strategies that we have adopted on our Beowulf Linux cluster at JPL.

Majid, W. A.; Chandra, I.; Kuiper, T.; Lazio, J.; Winterhalter, D.; Naudet, C.; Treumann, R.; Zarka, P.

2005-05-01

11

A 325-MHz GMRT survey of the Herschel-ATLAS/GAMA fields  

NASA Astrophysics Data System (ADS)

We describe a 325-MHz survey, undertaken with the Giant Metrewave Radio Telescope (GMRT), which covers a large part of the three equatorial fields at 9, 12 and 14.5 h of right ascension from the Herschel-Astrophysical Terahertz Large Area Survey (H-ATLAS) in the area also covered by the Galaxy And Mass Assembly (GAMA) survey. The full data set, after some observed pointings were removed during the data reduction process, comprises 212 GMRT pointings covering ˜90 deg2 of sky. We have imaged and catalogued the data using a pipeline that automates the process of flagging, calibration, self-calibration and source detection for each of the survey pointings. The resulting images have resolutions of between 14 and 24 arcsec and minimum rms noise (away from bright sources) of ˜1 mJy beam-1, and the catalogue contains 5263 sources brighter than 5?. We investigate the spectral indices of GMRT sources which are also detected at 1.4 GHz and find them to agree broadly with previously published results; there is no evidence for any flattening of the radio spectral index below S1.4 = 10 mJy. This work adds to the large amount of available optical and infrared data in the H-ATLAS equatorial fields and will facilitate further study of the low-frequency radio properties of star formation and AGN activity in galaxies out to z ˜ 1.

Mauch, Tom; Klöckner, Hans-Rainer; Rawlings, Steve; Jarvis, Matt; Hardcastle, Martin J.; Obreschkow, Danail; Saikia, D. J.; Thompson, Mark A.

2013-10-01

12

Visualizing Topography  

NSDL National Science Digital Library

Topographic maps that display three-dimensional landscapes on two-dimensional surfaces can offer a great deal of spatial information in minimal space. However, it is often difficult for people to interpret the features on a topographic map. This interactive feature adapted from Stephen Reynolds's 'Visualizing Topography' website offers color-enhanced and three-dimensional visualizations to help interpret two-dimensional topographic maps. Users can introduce shading, tilt, and rotate the maps to better see the three dimensional feature being represented by the map.

Reynolds, Stephen J.

2010-09-27

13

Visualizing Topography  

NSDL National Science Digital Library

Topographic maps that display three-dimensional landscapes on two-dimensional surfaces can offer a great deal of spatial information in minimal space. However, it is often difficult for people to interpret the features on a topographic map. This interactive feature adapted from Stephen Reynolds's 'Visualizing Topography' website offers color-enhanced and three-dimensional visualizations to help interpret two-dimensional topographic maps. Users can introduce shading, tilt, and rotate the maps to better see the three dimensional feature being represented by the map.

Reynolds, Stephen

2006-01-01

14

Tracking dispersion measure variations of timing array pulsars with the GMRT  

NASA Astrophysics Data System (ADS)

We present the results from nearly three years of monitoring of the variations in dispersion measure (DM) along the line-of-sight to 11 millisecond pulsars using the Giant Metrewave Radio Telescope (GMRT). These results demonstrate accuracies of single epoch DM estimates of the order of 5 × 10-4 cm-3 pc. A preliminary comparison with the Parkes Pulsar Timing Array (PPTA) data shows that the measured DM fluctuations are comparable. We show effects of DM variations due to the solar wind and solar corona and compare with the existing models.

Kumar, Ujjwal; Gupta, Yashwant; van Straten, Willem; Os?owski, Stefan; Roy, Jayanta; Bhat, N. D. R.; Bailes, Matthew; Keith, Michael J.

2013-03-01

15

Five Years of Multi-frequency Monitoring of GRB030329 Afterglow Using the GMRT and WSRT  

NASA Astrophysics Data System (ADS)

GRB 030329 displayed one of the brightest optical afterglows ever. We have followed the radio afterglow of GRB 030329 for over 5 years using the GMRT and WSRT at low radio frequencies. This is the longest as well as the lowest frequency follow up of any GRB afterglow ever. Radio observations of a GRB afterglow provide a unique probe of the physics of the blast wave at late times, when the expansion of the fireball slows down to non-relativistic speeds. Our GMRT-WSRT observations suggest that the afterglow of GRB030329 entered the non-relativistic phase around 60 days after the burst. The estimate of the fireball energy content, ~1051 erg, in this near-isotropic phase is much less susceptible to the collimation-related uncertainties arising in the relativistic phase. We have also been closely monitoring the evolution of the afterglow to look for possible signatures of emission from a counter jet, but no conclusive evidence has so far been found.

Kamble, Atish; van der Horst, A. J.; Bhattacharya, D.; Wijers, Ralph; Chandra, C. H. Ishwara; Resmi, L.; Rol, Evert; Kouveliotou, Chryssa; Strom, R.

2009-05-01

16

Five Years of Multi-frequency Monitoring of GRB030329 Afterglow Using the GMRT and WSRT  

NASA Astrophysics Data System (ADS)

GRB 030329 displayed one of the brightest optical afterglows ever. We have followed the radio afterglow of GRB 030329 for over 5 years using the GMRT and WSRT at low radio frequencies. This is the longest as well as the lowest frequency follow up of any GRB afterglow ever. Radio observations of a GRB afterglow provide a unique probe of the physics of the blast wave at late times, when the expansion of the fireball slows down to non-relativistic speeds. Our GMRT-WSRT observations suggest that the afterglow of GRB030329 entered the non-relativistic phase around 60 days after the burst. The estimate of the fireball energy content, ˜ 1051~erg, in this near-isotropic phase is much less susceptible to the collimation-related uncertainties arising in the relativistic phase. We have also been closely monitoring the evolution of the afterglow to look for possible signatures of emission from a counter jet, but no conclusive evidence has so far been found.

Kamble, A.; Horst, A. J. V.; Bhattacharya, D.; Wijers, R.; Chandra, C. H. I.; Resmi, L.; Rol, E.; Kouveliotou, C.; Strom, R.

2009-09-01

17

A search for steep spectrum radio relics and halos with the GMRT  

NASA Astrophysics Data System (ADS)

Context: Diffuse radio emission, in the form of radio halos and relics, traces regions in clusters with shocks or turbulence, probably produced by cluster mergers. The shocks and turbulence are important for the total energetics and detailed temperature distribution within the intracluster medium (ICM). Only a small fraction of clusters exhibit diffuse radio emission, whereas a large majority of well-studied clusters shows clear substructure in the ICM. Some models of diffuse radio emission in clusters indicate that virtually all clusters should contain diffuse radio sources with a steep spectrum. External accretion shocks associated with filamentary structures of galaxies could also accelerate electrons to relativistic energies and hence produce diffuse synchrotron emitting regions. The detection of radio emission from such filaments is important for our understanding of the origin of the Warm-Hot Intergalactic Medium (WHIM), and relativistic electrons and magnetic fields in the cosmic web. Here we report on Giant Metrewave Radio Telescope (GMRT) observations of a sample of steep spectrum sources from the 74 MHz VLSS survey. These sources are diffuse on scales ?15 arcsec, and not clearly associated with nearby (z ? 0.1) galaxies. Aims: The main aim of the observations is to search for diffuse radio emission associated with galaxy clusters or the cosmic web. Methods: We have carried out GMRT 610 MHz continuum observations of unidentified diffuse steep spectrum sources. Results: We have constructed a sample of diffuse steep spectrum sources, selected from the 74 MHz VLSS survey. We identified eight diffuse radio sources probably all located in clusters. We found five radio relics, one cluster with a giant radio halo and a radio relic, and one radio mini-halo. The giant radio halo has the highest radio power (P1.4) known to date. By complementing our observations with measurements from the literature we find correlations between the physical size of relics and the spectral index, in the sense that smaller relics have steeper spectra. Furthermore, larger relics are mostly located in the outskirts of clusters while smaller relics are located closer to the cluster center.

van Weeren, R. J.; Röttgering, H. J. A.; Brüggen, M.; Cohen, A.

2009-12-01

18

Topographies lacking tidal conversion  

Microsoft Academic Search

The consensus is that in a stratified sea a classical model of tidal flow over irregular\\u000abut smooth topography necessarily leads to the generation of internal tides, regardless\\u000aof the shape of the topography. This is referred to as tidal conversion. Here it is shown,\\u000ahowever, that there exists a large class of topographies for which there is neither tidal

Leo R. M. Maas

2011-01-01

19

Observations of solar coronal holes using radio (GMRT & GRH), extreme ultra-violet (SOHO-EIT) and X-ray (GOES-SXI) imaging instruments  

NASA Astrophysics Data System (ADS)

Solar observations with the Giant Metrewave Radio Telescope GMRT on 06 04 2005 at 150 MHz show evidence for a radio counterpart to a Coronal Hole CH observed as a depression in the radio brightness distribution on the solar disk In this work we compare the structural details of the radio CH using the GMRT observations and the Extreme Ultra Violet EUV and Soft X-Ray SXR images obtained with the SoHO EIT and GOES SXI respectively We also study the density temperature inside the same CH using 115 MHz data from the Gauribidanur Radioheliograph GRH We present and discuss our results for the radio counterpart to this CH focusing on the comparison of its position and size as determined from EUV and SXR with the parameters determined from the GMRT map and on the determination of plasma parameters from the GRH map

Madsen, F. R. H.; Ramesh, R.; Ananthakrishnan, S.; Subramanian, P.; Cecatto, J. R.; Sawant, H. S.

20

X Ray Topography  

ERIC Educational Resources Information Center

|Discusses some aspects in X-ray topography, including formation of dislocations, characteristics of stacking faults, x-ray contrast in defect inspection, Berg-Barrett technique, and Lang traversing crystal and Borrmann's methods. (CC)|

Balchin, A. A.

1974-01-01

21

Flow Interaction with Topography  

NSDL National Science Digital Library

This module explores the fundamental concepts used to determine how air flow interacts with topography. Using the simple analogy of a marble rolling over a hill, this module examines the relationship between wind speed and static stability of the atmosphere. These results are further extended to include three-dimensional terrain barriers as well as the evolution through time of the interaction.

Spangler, Tim

1999-05-01

22

GMRT mini-survey to search for 21-cm absorption in quasar-galaxy pairs at z ~ 0.1  

NASA Astrophysics Data System (ADS)

We present the results from our 21-cm absorption survey of a sample of five quasar-galaxy pairs (QGPs), with the redshift of the galaxies in the range 0.03 <= zg <= 0.18, selected from the Sloan Digital Sky Survey (SDSS). The HI 21-cm absorption was searched towards the nine sightlines with impact parameters ranging from ~10 to ~55 kpc using the Giant Metrewave Radio Telescope (GMRT). 21-cm absorption was detected only in one case, i.e. towards the quasar (zq = 2.625 SDSS J124157.54+633241.6)-galaxy (zg = 0.143 SDSS J124157.26+633237.6) pair with the impact parameter ~11 kpc. The quasar sightline in this case pierces through the stellar disc of a galaxy having near solar metallicity [i.e. (O/H)+12 = 8.7] and star formation rate uncorrected for dust attenuation of 0.1 Msolar yr-1. The quasar spectrum reddened by the foreground galaxy is well fitted with the Milky Way extinction curve (with an AV of 0.44) and the estimated HI column density is similar to the value obtained from 21-cm absorption assuming a spin temperature (TS) of 100 K. In the remaining cases, our GMRT spectra provide upper limit on N(HI) in the range (1017-1018) × TS cm-2. Combining our sample with the z <= 0.1 data available in the literature, we find the detectability of 21-cm absorption with integrated optical depth greater than 0.1 km s-1 to be 50 per cent for the impact parameter less than 20 kpc. Using the surface brightness profiles and a well-established relationship between the optical size and extent of the HI disc known for nearby galaxies, we conclude that in most of the cases of 21-cm absorption non-detection, the sightlines may not be passing through the HI gas (1? column density of a few times 1019 cm-2). We also find that in comparison to the absorption systems associated with these QGPs, z < 1 damped Lyman-? absorbers (DLAs) with 21-cm absorption detections have lower CaII equivalent widths despite having higher 21-cm optical depths and smaller impact parameters. This suggests that the current sample of DLAs may be a biased population that avoids sightlines through dusty star-forming galaxies. A systematic survey of QGPs over a wider redshift range using a large sample is needed to confirm these findings and understand the nature of 21-cm absorbers.

Gupta, N.; Srianand, R.; Bowen, D. V.; York, D. G.; Wadadekar, Y.

2010-10-01

23

The Extended GMRT Radio Halo Survey. I. New upper limits on radio halos and mini-halos  

NASA Astrophysics Data System (ADS)

Context. A fraction of galaxy clusters host diffuse radio sources called radio halos, radio relics and mini-halos. These are associated with the relativistic electrons and magnetic fields present on ~Mpc scales in the intra-cluster medium. Aims: We aim to carry out a systematic radio survey of all luminous galaxy clusters selected from the REFLEX and eBCS X-ray catalogues with the Giant Metrewave Radio Telescope, to understand the statistical properties of the diffuse radio emission in galaxy clusters. Methods: We present the sample and first results from the Extended GMRT Radio Halo Survey (EGRHS), which is an extension of the GMRT Radio Halo Survey (GRHS, Venturi et al. 2007, 2008). Analysis of radio data at 610/ 235/ 325 MHz on 12 galaxy clusters are presented. Results: We report the detection of a newly discovered mini-halo in the cluster RX J1532.9+3021 at 610 MHz. The presence of a small-scale relic (~200 kpc) is suspected in the cluster Z348. We do not detect cluster-scale diffuse emission in 11 clusters. Robust upper limits on the detection of radio halo of size of 1 Mpc are determined. We also present upper limits on the detections of mini-halos in a sub-sample of cool-core clusters. The upper limits for radio halos and mini-halos are plotted in the radio power- X-ray luminosity plane and the correlations are discussed. Diffuse extended emission that is not related to the target clusters, but detected as by-products in the sensitive images of two of the cluster fields (A689 and RX J0439.0+0715) is also reported. Conclusions: Based on the information about the presence of radio halos (or upper limits), available on 48 clusters out of the total sample of 67 clusters (EGRHS+GRHS), we find that 23 ± 7% of the clusters host radio halos. The radio halo fraction rises to 31 ± 11%, when only the clusters with X-ray luminosities >8 × 1044 erg s-1 are considered. Mini-halos are found in ~50% of cool-core clusters. A qualitative examination of the X-ray images of the clusters with no diffuse radio emission indicates that a majority of these clusters do not show extreme dynamical disturbances and supports the idea that mergers play an important role in generating radio halos and relics. The analysis of the full sample will be presented in a future work. Appendix A is available in electronic form at http://www.aanda.org

Kale, R.; Venturi, T.; Giacintucci, S.; Dallacasa, D.; Cassano, R.; Brunetti, G.; Macario, G.; Athreya, R.

2013-09-01

24

The Dawn Topography Investigation  

NASA Astrophysics Data System (ADS)

The objective of the Dawn topography investigation is to derive the detailed shapes of 4 Vesta and 1 Ceres in order to create orthorectified image mosaics for geologic interpretation, as well as to study the asteroids’ landforms, interior structure, and the processes that have modified their surfaces over geologic time. In this paper we describe our approaches for producing shape models, plans for acquiring the needed image data for Vesta, and the results of a numerical simulation of the Vesta mapping campaign that quantify the expected accuracy of our results. Multi-angle images obtained by Dawn’s framing camera will be used to create topographic models with 100 m/pixel horizontal resolution and 10 m height accuracy at Vesta, and 200 m/pixel horizontal resolution and 20 m height accuracy at Ceres. Two different techniques, stereophotogrammetry and stereophotoclinometry, are employed to model the shape; these models will be merged with the asteroidal gravity fields obtained by Dawn to produce geodetically controlled topographic models for each body. The resulting digital topography models, together with the gravity data, will reveal the tectonic, volcanic and impact history of Vesta, and enable co-registration of data sets to determine Vesta’s geologic history. At Ceres, the topography will likely reveal much about processes of surface modification as well as the internal structure and evolution of this dwarf planet.

Raymond, C. A.; Jaumann, R.; Nathues, A.; Sierks, H.; Roatsch, T.; Preusker, F.; Scholten, F.; Gaskell, R. W.; Jorda, L.; Keller, H.-U.; Zuber, M. T.; Smith, D. E.; Mastrodemos, N.; Mottola, S.

2011-12-01

25

Gallery of Virtual Topography  

NSDL National Science Digital Library

The Gallery of Virtual Topography features virtual depictions of topography, including 3D perspectives and QuickTime Virtual Reality (QTVR) movies, created from Digital Elevation Models (DEM's). The site showcases QTVR object movies where the user can spin a 3D terrain to view it from different perspectives. It also includes static 3D-perspective images (JPEG files) of the 3D terrains for those users with slower Internet connections. Some movies and images depict only the form of the landscape, but in others topographic contours are draped over the landscape to better illustrate how contours portray different types of topography (cliffs versus badlands, for example). Some animations illustrate the significance of contours, by allowing the user to progressively fill the landscape up with water to see the water interact with different topographic features. The site also contains a topographic contour map for each 3D terrain, so that instructors can develop student exercises, such as locating points on a map and constructing topographic profiles. Some QTVR movies contain numbered topographic features just for this purpose.

Reynolds, Stephen

26

Search for steady and transient radio pulses to-wards two new Fermi-LAT sources with GMRT  

NASA Astrophysics Data System (ADS)

The Large Area Telescope aboard Fermi spacecraft has discovered many new pulsars at high energies (Abdo et al. 2009). Sixteen of the 46 sources in this first catalog were discovered at positions of bright gamma-ray sources with no known radio counterparts, suggesting a large radio-quiet pulsar population. The non-detections of radio pulsars in these sources suggest an outer gap origin of the high energy emission and strict upper limits with radio observations of these sources are required. On the other hand, the detection of radio pulsation is useful for an improved timing solution and an estimate of distance. Two of these, PSRs J2238+59 and J1958+2846, without radio counterparts, lie in a region of sky, which was surveyed using GMRT at 610 MHz in a recently concluded radio pulsar survey (Joshi et al. 2009). We present upper limits on pulsed radio emission from our survey for these two sources and the results of a transient search to detect isolated bursts from these sources using the same data.

Joshi, Bhal Chandra; McLaughlin, Maura; Lorimer, Duncan; Kramer, Michael; Lyne, Andrew

27

AGN Feedback in the Compact Group of Galaxies HCG 62-as Revealed by Chandra, XMM and GMRT Data  

NASA Astrophysics Data System (ADS)

As a part of an ongoing study of a sample of galaxy groups showing evidence for AGN/hot gas interaction, we report on the preliminary results of an analysis of new XMM and GMRT data of the X-ray bright compact group HCG 62. This is one of the few groups known to possess very clear, small X-ray cavities in the inner region as shown by the existing Chandra image. At higher frequencies (>=1.4 GHz), the cavities show minimal if any radio emission, but the radio appears clearly at lower frequencies (<=610 MHz). We compare and discuss the morphology and spectral properties of the gas and of the radio source. We find that the cavities are close to being pressure balanced, and that the jets have a ``light'' hadronic content. By extracting X-ray surface brightness and temperature profiles, we also identify a shock front located around 35 kpc to the south-west of the group center.

Gitti, M.; O'Sullivan, E.; Giacintucci, S.; David, L.; Vrtilek, J.; Raychaudhury, S.; Nulsen, P.

2009-12-01

28

Ocean Surface Topography from Space  

NSDL National Science Digital Library

Interactive Flash Module about Ocean Surface Topography. Module includes sea surface observations and measurements as well as visuals explanations of the alimetry instruments used to detect surface changes.

Jet Propulsion Laboratory, California Institute of Technology, NASA

29

Gravity and topography  

NASA Astrophysics Data System (ADS)

The paper summarizes the fundamental gravity field constants for Mars and a brief historical review of early determinations and current-day accurate estimates. These include the planetary gravitational constant, global figure, dynamical oblateness, mean density, and rotational period. Topographic results from data acquired from the 1967 opposition to the most recent, 1988, opposition are presented. Both global and selected local topographic variations and features are discussed. The inertia tensor and the nonhydrostatic component of Mars are examined in detail. The dimensionless moment of inertia about the rotational axis is 0.4 for a body of uniform density and 0.37621 if Mars were in hydrostatic equilibrium. By comparing models of both gravity and topography, inferences are made about the degree and depth of compensation in the interior and stresses in the lithosphere.

Esposito, P. B.; Banerdt, W. B.; Lindal, G. F.; Sjogren, W. L.; Slade, M. A.; Bills, B. G.; Smith, D. E.; Balmino, G.

30

Dynamic topography in South America  

NASA Astrophysics Data System (ADS)

Supracrustal tectonics and mantle flow interact to create Earth's topography. While tectonics is associated with the isostatic components of topography, the deflections caused by mantle dynamics, or dynamic topography, represent the non-isostatic components. South America is an ideal natural laboratory to analyze these two contrasting components from the high Andes to the distal plains. Both regions are active and affected by complex geodynamic processes like the subduction of oceanic ridges, geometry and age of slabs, etc. These subducting anomalies affect not only the convergence dynamics and stresses along the entire margin, but also the distribution of mass anomalies in the mantle, which are the main cause of sublithospheric flow and dynamic topography. Here we revisited five examples from north to south, which demonstrate that, the Andes and the distal forelands have been uncompensated since the beginning of the Cenozoic and that additional forces, such as mantle downwellings and upwellings, are required to account for the observed topographies in basins and elevations.

Dávila, Federico M.; Lithgow-Bertelloni, Carolina

2013-04-01

31

Density, Isostasy, and Topography  

NSDL National Science Digital Library

Show caption HideA critical component of this activity involves sharing team data with the entire class, done the old-fashioned way on the chalkboard. Details This activity begins with an exploration of a topographic map of the earth, ending with the question: Why is the distribution of topography on the earth bimodal? The students then collect two forms of data. They measure the density of the most common rocks that make up oceanic crust (basalt), continental crust (granite), and the mantle (peridotite). They also measure the density of several different kinds of wood, and how high each kind floats in a tub of water. In each case, they work in teams of two or three and then the entire class shares their data. Based on the data from the wood, they derive an equation that relates the density of the wood to the height at which the block floats in the water - the isostasy equation. They then substitute density values for real rocks into their equation to derive thicknesses for average continental and oceanic crust, and apply their knowledge in order to draw a cross-section of the crust across South America. This activity gives students a real, hands-on and mathematical understanding of the principle of isostasy.

Egger, Anne

32

Rhythmic Patterns of Beach Topography.  

National Technical Information Service (NTIS)

Rhythmic patterns of topography may be apparent simultaneously in a longshore alternation of cuspate projections and arcuate embayments along the beach face, in a rhythmic longshore bar composed of an alternate series of arcs and cusps, and in longshore u...

J. L. van Beek

1974-01-01

33

Hillslope Topography from Unconstrained Photographs  

Microsoft Academic Search

Quantifications of Earth surface topography are essential for modeling the connections between physical and chemical processes of erosion and the shape of the landscape. Enormous investments are made in developing and testing process-based landscape evolution models. These models may never be applied to real topography because of the difficulties in obtaining high-resolution (1–2 m) topographic data in the form of

Arjun M. Heimsath; Hany Farid

2002-01-01

34

Global Multi-Resolution Topography synthesis  

Microsoft Academic Search

Seafloor bathymetric data acquired with modern swath echo sounders provide coverage for only a small fraction of the global seabed yet are of high value for studies of the dynamic processes of seafloor volcanism, tectonics, mass wasting, and sediment transport that create and shape the undersea landscape. A new method for compilation of global seafloor bathymetry that preserves the native

William B. F. Ryan; Suzanne M. Carbotte; Justin O. Coplan; Suzanne O'Hara; Andrew Melkonian; Robert Arko; Rose Anne Weissel; Vicki Ferrini; Andrew Goodwillie; Frank Nitsche; Juliet Bonczkowski; Richard Zemsky

2009-01-01

35

Measured and Estimated Seafloor Topography: Land Topography from GTOPO30  

NSDL National Science Digital Library

This web site displays two "clickable" maps - one topographic, and the other a Ship Track Each of 16 regions on the maps displays measured and estimated seafloor topography. A poster of the images can be ordered for a fee. Links to related sites are also provided.

36

The Shuttle Radar Topography Mission  

Microsoft Academic Search

The Shuttle Radar Topography Mission produced the most complete, highest-resolution digital elevation model of the Earth. The project was a joint endeavor of NASA, the National Geospatial-Intelligence Agency, and the German and Italian Space Agencies and flew in February 2000. It used dual radar antennas to acquire interferometric radar data, processed to digital topographic data at 1 arc sec resolution.

Tom G. Farr; Paul A. Rosen; Edward Caro; Robert Crippen; Riley Duren; Scott Hensley; Michael Kobrick; Mimi Paller; Ernesto Rodriguez; Ladislav Roth; David Seal; Scott Shaffer; Joanne Shimada; Jeffrey Umland; Marian Werner; Michael Oskin; Douglas Burbank; Douglas Alsdorf

2007-01-01

37

X-ray Topography in Protein Crystals  

NASA Astrophysics Data System (ADS)

X-ray topography, especially synchrotron X-ray topography, provides a useful tool for the characterization of protein crystals in order to characterize the defects. We observed clear images of dislocations in hen-egg white lysozyme crystals. In this article we overviewed the research on crystal defects, especially dislocations of protein crystals by synchrotron X-ray topography.

Kojima, Kenichi; Tachibana, Masaru

38

The topography of Iapetus' leading side  

Microsoft Academic Search

We have used Cassini stereo images to study the topography of Iapetus' leading side. A terrain model derived at resolutions of 4–8 km reveals that Iapetus has substantial topography with heights in the range of ?10 km to +13 km, much more than observed on the other middle-sized satellites of Saturn so far. Most of the topography is older than

Bernd Giese; Tilmann Denk; Gerhard Neukum; Thomas Roatsch; Paul Helfenstein; Peter C. Thomas; Elizabeth P. Turtle; Alfred McEwen; Carolyn C. Porco

2008-01-01

39

Topography, Cell Response, and Nerve Regeneration  

PubMed Central

In the body, cells encounter a complex milieu of signals, including topographical cues. Imposed topography can affect cells on surfaces by promoting adhesion, spreading, alignment, morphological changes, and changes in gene expression. Neural response to topography is complex, and depends on the dimensions and shapes of physical features. Looking toward repair of nerve injuries, strategies are being explored to engineer guidance conduits with precise surface topographies. How neurons and other cell types sense and interpret topography remains to be fully elucidated. Studies reviewed here include those of topography on cellular organization and function as well as potential cellular mechanisms of response.

Hoffman-Kim, Diane; Mitchel, Jennifer A.; Bellamkonda, Ravi V.

2010-01-01

40

Stem Cell Interaction with Topography  

Microsoft Academic Search

\\u000a The growth and differentiation of stem cells are regulated by biochemical and biophysical cues in the extracellular microenvironment.\\u000a Increasing evidences have shown that substrate topography, one of the biophysical properties of the microenvironment, can\\u000a affect stem cell fate, such as the maintenance of embryonic stem cells and the differentiation of adult and embryonic stem\\u000a cells. The underlying mechanism of how

Benjamin K. K. Teo; Soneela Ankam; Evelyn K. F. Yim

41

Venus topography - A harmonic analysis  

Microsoft Academic Search

A model of Venusian global topography has been obtained by fitting an eighteenth-degree harmonic series to Pioneer Venus orbiter radar altimeter data. The mean radius is (6051.45 + or - 0.04) km. The corresponding mean density is (5244.8 + or 0.5) kg\\/cu m. The center of figure is displaced from the center of mass by (0.339 + or - 0.088)

B. G. Bills; Michael Kobrick

1985-01-01

42

Whitebeam X-ray topography  

Microsoft Academic Search

After radiography, white-beam X-ray topography (XRT) is the simplest X-ray imaging technique for crystals. An X-ray topograph is formed by a Bragg reflexion and is in effect a high-spatial-resolution Laue ‘spot’. Synchrotron radiation has given XRT additional powers, with its broad continuous spectrum, small beam divergence, high intensity, strong polarization and regular pulsed time structure. Each Laue image, however, may

Moreton Moore

2012-01-01

43

Topography of inner core boundary  

NASA Astrophysics Data System (ADS)

Precise determination of the topography of a major internal boundary of the Earth is difficult because of the trade-off with the unknown velocity structure above it. However, the discoveries of the inner core (IC) rotation and high-quality teleseismic waveform doublets make the precise mapping of the topography of the inner core boundary (ICB) possible, as demonstrated in recent studies. Here we examine IC refracted (PKP-DF) and reflected (PKP-CD) waves recorded at the Yellowknife Array and global stations from 13 high-quality doublets, among a large collection of doublets in S. Sandwich Islands that we have assembled. Our results show clear evidence for spatial and temporal variations of IC reflections in travel times and in waveforms. If the time separation (dT) between the two members of the doublet is less than 3 years, the IC arrivals show little temporal change in travel times or waveforms. If dT is greater than about 6 years, some doublets show large variations but some others do not. The ICB regions beneath Atlantic Ocean and Indian Ocean show little temporal change. The regions show large variations are beneath Africa and the Central America, which coincide with large seismic anomalies at the core-mantle boundary (CMB). Inside these two ICB regions, there are fine-scale (km scale) variations. The largest temporal changes of IC reflections are about 0.10 to 0.15 s, corresponding to a topographic variation of up to 3.7 to 5.6 km. The results suggest ICB topography of a few kms on fine to regional scales. Dynamical models include a bumpy ICB rotating with the IC itself or a transient slurry boundary sloshing about in the turbulence at the base of the convecting outer core. The geographical coincidence of the ICB and CMB anomalies may suggest strong thermal coupling of the mantle and the core.

Song, X.; Dai, W.

2007-12-01

44

Plasma processing for nanostructured topographies  

NASA Astrophysics Data System (ADS)

Plasma and directed ion interactions with materials have been widely observed to create complex surface patterns on a micro- and nano- scale. Generally, these texturizations are byproducts of another intended application (such as a feature formation on a sputtering target) and patterning is considered inconsequential or even detrimental. This work examined the possibility of using these phenomena as primary methods for producing beneficial topographies. Specifically, investigations focused on the use of helium plasma exposure and directed ion etching to create nanostructured surfaces capable of affecting biological interactions with implanted materials. Orthogonal argon ion etching and low energy helium plasma texturization of titanium were considered for use on orthopedic and dental implants as a means of increasing osteoblast activity and bone attachment; and oblique angle etching was evaluated for its use in creating topographies with cell deterrent or anti-thrombogenic properties. In addition, the helium driven evolution of surface features on 6061 aluminum alloy was characterized with respect to ion energy and substrate temperature. These surfaces were then considered for ice phobic applications.

Riedel, Nicholas Alfred

45

Tectonics, Climate, and Mountain Topography  

NASA Astrophysics Data System (ADS)

By regressing simple, independent variables that describe climate and tectonic processes against measures of topography and relief of 69 mountain ranges worldwide, we quantify the relative importance of these processes in shaping observed landscapes. Climate variables include latitude (as a surrogate for mean annual temperature and insolation, but most importantly for the likelihood of glaciation) and mean annual precipitation. To quantify tectonics we use shortening rates across each range. As a measure of topography, we use mean and maximum elevations and relief calculated over different length scales. We show that the combination of climate (negative correlation) and tectonics (positive correlation) explain substantial fractions (> 25%, but < 50%) of mean and maximum elevations of mountain ranges, but that shortening rates account for smaller portions, <25%, of the variance in most measures of topography and relief (i.e. with low correlations and large scatter). Relief is insensitive to mean annual precipitation, but does depend on latitude, especially for relief calculated over small (~1 km) length scales, which we infer to reflect the importance of glacial erosion. Larger-scale (averaged over length scales of ~10 km) relief, however, correlates positively with tectonic shortening rate. Moreover, the ratio between small-scale and large-scale relief, as well as the relative relief (the relief normalized by the mean elevation of the region) varies most strongly with latitude (strong positive correlation). Therefore, the location of a mountain range on Earth and corresponding climatic conditions, not just tectonic forcing, appears to be a key factor in determining its shape and size. In any case, the combination of tectonics and climate, as quantified here, can account for approximately half of the variance in these measures of topography. The failure of present-day shortening rates to account for more than 25% of most measures of relief raises the question: Is active tectonics overrated in attempts to account for present-day relief and exhumation rates of high terrain? The following points are of particular importance: 1) Elevations of ranges directly reflect the interaction between tectonics, which thickens the crust, and therefore increases elevations, and climate (through erosion), which thins the crust, and hence decreases the elevation. The importance of tectonics appears to be modest in most cases, and suggests that although tectonics is obviously essential for mountain building, but the shapes of mature ranges appear to be controlled mostly by climate factors, that cause a large scatter. 2) Relief is not sensitive to mean annual precipitation amounts, but increases with shortening rates and latitude (hence glacial erosion). Relief averaged over large areas is not affected much by climatic factors, and more by tectonics, but relief measured on short distance scales correlates best with a combination of tectonics and latitude. Relief in high-latitude mountain ranges result largely from glacial excavation at valley scale of the topography created by tectonics. 3) The location of a mountain range on Earth appears to be an important factor in determining its elevation. Latitude also correlates with relief measured on short distance scales and the relative relief (the amount of relief scaled to the mean elevation of the range). Presumably, the climatic differences that vary with latitude, glaciers in particular, play a crucial role in shaping that relief.

Champagnac, J.-D.; Molnar, P.; Sue, C.; Herman, F.

2012-04-01

46

Exploring scaling laws in surface topography  

Microsoft Academic Search

Surface topography affects many soil properties and processes, particularly surface water storage and runoff. Application of fractal analysis helps understand the scaling laws inherent in surface topography at a wide range of spatial scales and climatic regimes. In this research, a high resolution digital elevation model with a 3mm resolution on one side of the spectrum and large scale DEMs,

M. J. Abedini; M. R. Shaghaghian

2009-01-01

47

Venus - Global gravity and topography  

NASA Astrophysics Data System (ADS)

A new gravity field determination that has been produced combines both the Pioneer Venus Orbiter (PVO) and the Magellan Doppler radio data. Comparisons between this estimate, a spherical harmonic model of degree and order 21, and previous models show that significant improvements have been made. Results are displayed as gravity contours overlaying a topographic map. We also calculate a new spherical harmonic model of topography based on Magellan altimetry, with PVO altimetry included where gaps exist in the Magellan data. This model is also of degree and order 21, so in conjunction with the gravity model, Bouguer and isostatic anomaly maps can be produced. These results are very consistent with previous results, but reveal more spatial resolution in the higher latitudes.

McNamee, J. B.; Borderies, N. J.; Sjogren, W. L.

1993-05-01

48

Topography and Landforms of Ecuador  

USGS Publications Warehouse

EXPLANATION The digital elevation model of Ecuador represented in this data set was produced from over 40 individual tiles of elevation data from the Shuttle Radar Topography Mission (SRTM). Each tile was downloaded, converted from its native Height file format (.hgt), and imported into a geographic information system (GIS) for additional processing. Processing of the data included data gap filling, mosaicking, and re-projection of the tiles to form one single seamless digital elevation model. For 11 days in February of 2000, NASA, the National Geospatial-Intelligence Agency (NGA), the German Aerospace Center (DLR), and the Italian Space Agency (ASI) flew X-band and C-band radar interferometry onboard the Space Shuttle Endeavor. The mission covered the Earth between 60?N and 57?S and will provide interferometric digital elevation models (DEMs) of approximately 80% of the Earth's land mass when processing is complete. The radar-pointing angle was approximately 55? at scene center. Ascending and descending orbital passes generated multiple interferometric data scenes for nearly all areas. Up to eight passes of data were merged to form the final processed SRTM DEMs. The effect of merging scenes averages elevation values recorded in coincident scenes and reduces, but does not completely eliminate, the amount of area with layover and terrain shadow effects. The most significant form of data processing for the Ecuador DEM was gap-filling areas where the SRTM data contained a data void. These void areas are a result of radar shadow, layover, standing water, and other effects of terrain, as well as technical radar interferometry phase unwrapping issues. To fill these gaps, topographic contours were digitized from 1:50,000 - scale topographic maps which date from the mid-late 1980's (Souris, 2001). Digital contours were gridded to form elevation models for void areas and subsequently were merged with the SRTM data through GIS and remote sensing image-processing techniques. The data contained in this publication includes a gap filled, countrywide SRTM DEM of Ecuador projected in Universal Transverse Mercator (UTM) Zone 17 North projection, Provisional South American, 1956, Ecuador datum and a non gap filled SRTM DEM of the Galapagos Islands projected in UTM Zone 15 North projection. Both the Ecuador and Galapagos Islands DEMs are available as an ESRI Grid, stored as ArcInfo Export files (.e00), and in Erdas Imagine (IMG) file formats with a 90 meter pixel resolution. Also included in this publication are high and low resolution Adobe Acrobat (PDF) files of topography and landforms maps in Ecuador. The high resolution map should be used for printing and display, while the lower resolution map can be used for quick viewing and reference purposes.

Chirico, Peter G.; Warner, Michael B.

2005-01-01

49

Scanning Radar Altimeter for Mapping Continental Topography.  

National Technical Information Service (NTIS)

Topographic information constitutes a fundamental data set for the Earth sciences. In the geological and geophysical sciences, topography combined with gravitational information provides an important constraint on the structure and rheologic properties of...

T. H. Dixon

1986-01-01

50

Global Seafloor Topography from Satellite Altimetry  

NSDL National Science Digital Library

This site offers links to maps, posters, globes, and CD-ROMS showing seafloor topography, gravity anomalies, and bathymetry. The images were derived from GEOSAT and ERS satellite data and bathymetric surveys performed by the U.S. Navy.

51

Genetic topography of brain morphology.  

PubMed

Animal data show that cortical development is initially patterned by genetic gradients largely along three orthogonal axes. We previously reported differences in genetic influences on cortical surface area along an anterior-posterior axis using neuroimaging data of adult human twins. Here, we demonstrate differences in genetic influences on cortical thickness along a dorsal-ventral axis in the same cohort. The phenomenon of orthogonal gradations in cortical organization evident in different structural and functional properties may originate from genetic gradients. Another emerging theme of cortical patterning is that patterns of genetic influences recapitulate the spatial topography of the cortex within hemispheres. The genetic patterning of both cortical thickness and surface area corresponds to cortical functional specializations. Intriguingly, in contrast to broad similarities in genetic patterning, two sets of analyses distinguish cortical thickness and surface area genetically. First, genetic contributions to cortical thickness and surface area are largely distinct; there is very little genetic correlation (i.e., shared genetic influences) between them. Second, organizing principles among genetically defined regions differ between thickness and surface area. Examining the structure of the genetic similarity matrix among clusters revealed that, whereas surface area clusters showed great genetic proximity with clusters from the same lobe, thickness clusters appear to have close genetic relatedness with clusters that have similar maturational timing. The discrepancies are in line with evidence that the two traits follow different mechanisms in neurodevelopment. Our findings highlight the complexity of genetic influences on cortical morphology and provide a glimpse into emerging principles of genetic organization of the cortex. PMID:24082094

Chen, Chi-Hua; Fiecas, Mark; Gutiérrez, E D; Panizzon, Matthew S; Eyler, Lisa T; Vuoksimaa, Eero; Thompson, Wesley K; Fennema-Notestine, Christine; Hagler, Donald J; Jernigan, Terry L; Neale, Michael C; Franz, Carol E; Lyons, Michael J; Fischl, Bruce; Tsuang, Ming T; Dale, Anders M; Kremen, William S

2013-09-30

52

Improved Lunar Control and Topography  

NASA Astrophysics Data System (ADS)

We are completing the Unified Lunar Control Network (ULCN) 2005, an update and combination of the ULCN (Davies and Colvin 1994) and the Clementine LCN (CLCN) (unpublished) on which USGS Clementine mosaics are based. The new network should correct for large ( 7 km average to > 15 km) errors in the CLCN by constraining ULCN positions and camera angles, and by solving for radii at all points rather than assuming a sphere. The result will be a 3-D network, including a globally complete and consistent topographic model for the Moon tied directly to horizontal control. The estimated horizontal accuracy of our current solution ranges from 1 km in the areas of ULCN points to 3 km outside these areas. The current ULCN has a vertical accuracy of a few hundred meters when compared to Clementine lidar. The true accuracy may be higher, due to interpolation and lidar positional errors involved in the comparison. The final version should be available at the time of the DPS. Our current solution includes 546,142 image measures of 272,949 points and 43,866 Clementine (mostly 750-nm) images. We will report the results in a peer-reviewed article and distribute the network data from our website (http://astrogeology.usgs.gov/Projects/ControlNetworks/). This solution will be useful for scientific study of lunar morphology and basins; and for operational uses in selecting and targeting landing sites and evaluating landing hazards due to topography. A future solution will include Lunar Orbiter, Mariner 10, and Galileo data. Additionally, it will serve as the basis for solutions with data from upcoming missions, thus placing all data in one consistent coordinate system. We acknowledge the initiation of this work by T. Colvin and (the late) M. Davies at RAND, and funding from the NASA PG&G program.

Archinal, B. A.; Rosiek, M. R.; Kirk, R. L.; Redding, B. L.

2005-08-01

53

Corneal topography measurements for biometric applications  

NASA Astrophysics Data System (ADS)

The term biometrics is used to describe the process of analyzing biological and behavioral traits that are unique to an individual in order to confirm or determine his or her identity. Many biometric modalities are currently being researched and implemented including, fingerprints, hand and facial geometry, iris recognition, vein structure recognition, gait, voice recognition, etc... This project explores the possibility of using corneal topography measurements as a trait for biometric identification. Two new corneal topographers were developed for this study. The first was designed to function as an operator-free device that will allow a user to approach the device and have his or her corneal topography measured. Human subject topography data were collected with this device and compared to measurements made with the commercially available Keratron Piccolo topographer (Optikon, Rome, Italy). A third topographer that departs from the standard Placido disk technology allows for arbitrary pattern illumination through the use of LCD monitors. This topographer was built and tested to be used in future research studies. Topography data was collected from 59 subjects and modeled using Zernike polynomials, which provide for a simple method of compressing topography data and comparing one topographical measurement with a database for biometric identification. The data were analyzed to determine the biometric error rates associated with corneal topography measurements. Reasonably accurate results, between three to eight percent simultaneous false match and false non-match rates, were achieved.

Lewis, Nathan D.

54

Shortwave radiation parameterization scheme for subgrid topography  

NASA Astrophysics Data System (ADS)

Topography is well known to alter the shortwave radiation balance at the surface. A detailed radiation balance is therefore required in mountainous terrain. In order to maintain the computational performance of large-scale models while at the same time increasing grid resolutions, subgrid parameterizations are gaining more importance. A complete radiation parameterization scheme for subgrid topography accounting for shading, limited sky view, and terrain reflections is presented. Each radiative flux is parameterized individually as a function of sky view factor, slope and sun elevation angle, and albedo. We validated the parameterization with domain-averaged values computed from a distributed radiation model which includes a detailed shortwave radiation balance. Furthermore, we quantify the individual topographic impacts on the shortwave radiation balance. Rather than using a limited set of real topographies we used a large ensemble of simulated topographies with a wide range of typical terrain characteristics to study all topographic influences on the radiation balance. To this end slopes and partial derivatives of seven real topographies from Switzerland and the United States were analyzed and Gaussian statistics were found to best approximate real topographies. Parameterized direct beam radiation presented previously compared well with modeled values over the entire range of slope angles. The approximation of multiple, anisotropic terrain reflections with single, isotropic terrain reflections was confirmed as long as domain-averaged values are considered. The validation of all parameterized radiative fluxes showed that it is indeed not necessary to compute subgrid fluxes in order to account for all topographic influences in large grid sizes.

Helbig, N.; LöWe, H.

2012-02-01

55

Shuttle radar topography mapper (SRTM)  

NASA Astrophysics Data System (ADS)

The use of interferometric SAR (IFSAR) to measure elevation is one of the most powerful and promising capabilities of radar. A properly equipped spaceborne IFSAR system can produce a highly accurate global digital elevation map, including cloud-covered areas, in significantly less time and at significantly lower cost than with other systems. For accurate topography, the interferometric measurements must be performed simultaneously in physically sperate receive system, since measurements made at different times with the same system suffer significant decorrelation. The US/German/Italian spaceborne imaging radar C/X-band SAR (SIR-C/X-SAR), successfully flown twice in 1994 aboard the Space Shuttle Endeavor, offers a unique opportunity for global multifrequency elevation mapping by the year 2000. With appropriate augmentation, SIR-C/X-SAR is capable of producing an accurate elevation map covering 80 percent of the Earth's land surface in a single 10-day Shuttle flight. The existing US SIR-C SCANSAR mode provides a 225-km swath at C-band, which makes this coverage possible. Addition of a C-band receive antenna, extended from the Shuttle bay on a mast and operating in concert with the existing SIR-C antenna, produces an interferometric pair. Accuracy is enhanced by utilizing the SIR-C dual polarizations simultaneously to form separate SCANSAR beams. Due to the practical limitation of approximately 60 meters for the mast length, the longer SIR-C L-band wavelength does not produce useful elevation measurement accuracy. IFSAR measurements can also be obtained by the German/Italian X-SAR, simultaneously with SIR-C, by utilizing an added outboard antenna at X-band to produce a swath coverage of about 50 km. Accuracy can be enhanced at both frequencies by processing both ascending and descending data takes. It is estimated that the 90 percent linear absolute elevation error achievable is less that 16 meters for elevation postings of 30 meters. This will be the first use of spaceborne IFSAR to acquire accurate topographic data on a global scale.

Jordan, Rolando L.; Caro, Edward R.; Kim, Yunjin; Kobrick, Michael; Shen, Yuhsyen; Stuhr, Frederick V.; Werner, Marian U.

1996-12-01

56

Evaluation of corneal thickness and topography in normal eyes using the Orbscan corneal topography system  

Microsoft Academic Search

AIMSTo map the thickness, elevation (anterior and posterior corneal surface), and axial curvature of the cornea in normal eyes with the Orbscan corneal topography system.METHODS94 eyes of 51 normal subjects were investigated using the Orbscan corneal topography system. The anterior and posterior corneal elevation maps were classified into regular ridge, irregular ridge, incomplete ridge, island, and unclassified patterns, and the

Zuguo Liu; Andrew J Huang; Stephen C Pflugfelder

1999-01-01

57

The evolution of topography on a comet  

NASA Astrophysics Data System (ADS)

The authors have developed a simple model of an infinite cylindrical trench on a comet. The energy balance equation has been modified to include physical processes which are relevant with topography present, and includes shadowing, radiative heating from the opposing walls, and the condensation energy of sublimed gas molecules striking the walls instead of escaping to space. The model is designed to indicate the general course of the evolution of topography on a comet, and is not intended as a complete model of a cometary nucleus. By running the model for trenches of different depths and at different solar distances, the authors draw conclusions about the evolution of topography through an orbit and the consequences this evolution has on the evolution of the nucleus as a whole over the course of several perihelion passages.

Colwell, J. E.; Jakosky, B. M.

1987-10-01

58

Topography of Earth's Inner Core Boundary  

NASA Astrophysics Data System (ADS)

Lateral variations in the structure and crystallization of the inner core will likely be associated with lateral variations in the topography of its boundary. Depending on liquid fraction and the ratio of solid over liquid viscosity, the process of compaction of solids and expulsion of fluids at the solidifying boundary can be dynamically unstable, resulting in small-scale corrugations of the boundary of 0.1 to 5 km height with a horizontal scale on the order of 1 to 10 km. Evidence of such ICB topography has been inferred from waveforms of PKiKP doublets (1). An additional observation consistent ICB topography includes the seismic wave diffracted around the top of the inner core (PKP-Cdiff), whose travel time agrees with that predicted by the AK135 Earth model, but whose amplitude decays more rapidly into the inner core shadow than is predicted by AK135 (2). These observations are modeled by synthesizing seismic body waves with a pseudospectral method (3) having a densified grid in the vicinity of a rough ICB. Validation of the forward modeling includes a comparison of results obtained with a boundary element method. Modeled spectra of ICB topography are used to constrain the parameters and processes that produce the topography. These include compaction length (assuming freezing upward from below), the structure of precipitated piles (assuming metallic snow falling from above), the sedimentary processes due to flow in the overlying F-layer of the outer core, and the relaxation of topography from viscous deformation of the inner core. 1. Cao, A., Y. Masson, and B. Romanowicz, PNAS, 104, 31-35, 2007. 2. Zou, Z., K. Koper, and V.F. Cormier, J. Geophys. Res., 113, 2008. doi: 10.1029/2007JB005316. 3. Furumura T., B.L.N. Kennett, and M. Furumura, Geophys. J. Int., 135, 845--860, 1998.

Cormier, V. F.; Zheng, Y.; Hernlund, J. W.

2011-12-01

59

Noninterferometric topography measurements of fast moving surfaces.  

PubMed

The topography of moving surfaces is recovered by noninterferometric measurements. The phase reconstruction is derived by measuring the intensities of a backscattered pulsed laser light and solving the transport intensity equation (TIE). The TIE is solved by expanding the phase into a series of Zernike polynomials, leading to a set of appropriate algebraic equations. This technique, which enables us to make a direct connection between experiments and the TIE, has been successfully tested in gas gun experiments. In particular, the topographies of a moving projectile and the free surface of a shocked target were recovered. PMID:21811317

Pinhasi, Shirly Vinikman; Eliezer, Shalom; Glam, Benny; Appelbaum, Gabi; Bakshi, Lior

2011-08-01

60

Effects of patterned topography on biofilm formation  

NASA Astrophysics Data System (ADS)

Bacterial biofilms are a population of bacteria attached to each other and irreversibly to a surface, enclosed in a matrix of self-secreted polymers, among others polysaccharides, proteins, DNA. Biofilms cause persisting infections associated with implanted medical devices and hospital acquired (nosocomial) infections. Catheter-associated urinary tract infections (CAUTIs) are the most common type of nosocomial infections accounting for up to 40% of all hospital acquired infections. Several different strategies, including use of antibacterial agents and genetic cues, quorum sensing, have been adopted for inhibiting biofilm formation relevant to CAUTI surfaces. Each of these methods pertains to certain types of bacteria, processes and has shortcomings. Based on eukaryotic cell topography interaction studies and Ulva linza spore studies, topographical surfaces were suggested as a benign control method for biofilm formation. However, topographies tested so far have not included a systematic variation of size across basic topography shapes. In this study patterned topography was systematically varied in size and shape according to two approaches 1) confinement and 2) wetting. For the confinement approach, using scanning electron microscopy and confocal microscopy, orienting effects of tested topography based on staphylococcus aureus (s. aureus) (SH1000) and enterobacter cloacae (e. cloacae) (ATCC 700258) bacterial models were identified on features of up to 10 times the size of the bacterium. Psuedomonas aeruginosa (p. aeruginosa) (PAO1) did not show any orientational effects, under the test conditions. Another important factor in medical biofilms is the identification and quantification of phenotypic state which has not been discussed in the literature concerning bacteria topography characterizations. This was done based on antibiotic susceptibility evaluation and also based on gene expression analysis. Although orientational effects occur, phenotypically no difference was observed between the patterned topography tested. Another potential strategy for biofilm control through patterned topography is based on the design of robust non-wetting surfaces with undercut feature geometries, characterized by 1) breakthrough pressure and 2) triple phase contact line model. It was found that height and presence of undercut had statistically significant effects, directly proportional to breakthrough pressures, whereas extent of undercut did not. A predictive triple phase contact line model was also developed. (Full text of this dissertation may be available via the University of Florida Libraries web site. Please check http://www.uflib.ufl.edu/etd.html)

Vasudevan, Ravikumar

61

The topography of multivariate normal mixtures  

Microsoft Academic Search

Multivariate normal mixtures provide a flexible method of fitting high-dimensional data. It is shown that their topography, in the sense of their key features as a density, can be analyzed rigorously in lower dimensions by use of a ridgeline manifold that contains all critical points, as well as the ridges of the density. A plot of the elevations on the

Surajit Ray; Bruce G. Lindsay

2005-01-01

62

THE TOPOGRAPHY OF MULTIVARIATE NORMAL MIXTURES1  

Microsoft Academic Search

Multivariate normal mixtures provide a flexible method of fitting high- dimensional data. It is shown that their topography, in the sense of their key features as a density, can be analyzed rigorously in lower dimensions by use of a ridgeline manifold that contains all critical points, as well as the ridges of the density. A plot of the elevations on

SURAJIT RAY; BRUCE G. LINDSAY

63

The topography of multivariate normal mixtures  

Microsoft Academic Search

Multivariate normal mixtures provide a flexible method of fitting high-dimensional data. It is shown that their topography, in the sense of their key features as a density, can be analyzed rigorously in lower dimensions by use of a ridgeline manifold that contains all critical points, as well as the ridges of the density. A plot of the elevations on the

Surajit Ray; Bruce G. Lindsay

2006-01-01

64

Bottom Topography Effects on Ocean Currents.  

National Technical Information Service (NTIS)

The effects of bottom topography on ocean currents are considered. it is shown that a laminar laboratory model with height to width ratio differing from that of large scale geophysical motions can be used to model topographic effects on ocean currents. Th...

J. R. Guala

1972-01-01

65

Ocean Surface Topography from Space - Science  

NSDL National Science Digital Library

This site, from the Jet Propulsion Laboratory at the California Institute of Technology, describes the scientific applications of ocean surface topography from missions such as TOPEX/Poseidon and Jason-1. Other topics include uses of the collected data, such as evaluations of ocean circulation, tides, weather and climate patterns, and other trends.

Laboratory, Jet P.; Nasa

66

The relationship between Martian gravity and topography  

Microsoft Academic Search

The relationship between gravity and topography of various regions of Mars is used to estimate their effective elastic thicknesses Te using direct measurements of line of sight velocity, rather than spherical harmonic coefficients. Estimates of Te vary from 70 km for Tharsis, 29 km for Elysium, to 14.5 km for the southern hemisphere, and show that the thickness of the

Dan McKenzie; David N. Barnett; Dah-Ning Yuan

2002-01-01

67

Shallow waters viscous flows for arbitrary topography  

Microsoft Academic Search

In this paper, we obtain new models for gravity driven shallow water laminar flows in several space dimensions over a general topography. These models are derived from the incompressible Navier Stokes equations with no-slip condition at the bottom and include capillary effects. No partic- ular assumption is made on the size of the viscosity and on the variations of the

Marc Boutounet; Laurent Chupin; Pascal Noble; Jean Paul Vila

68

Reconstructing ancient topography through erosion modelling  

Microsoft Academic Search

One of the main aims of geomorphology is to understand how geomorphic processes change topography over long time scales. Over the last decades several landscape evolution models have been developed in order to study this question. However, evaluation of such models has often been very limited due to the lack of necessary field data. In this study we present a

Iris Peeters; Tom Rommens; Gert Verstraeten; Gerard Govers; Anton Van Rompaey; Jean Poesen; Kristof Van Oost

2006-01-01

69

Three-Dimensional Edge Waves on Curved Topographies.  

National Technical Information Service (NTIS)

Exact solutions are found to the linearized three dimensional equations for free surface gravity waves trapped against a straight coastline with a variable (perpendicular to the coastline) topography. Three families of topographies are found, one concave ...

R. P. Shaw

1979-01-01

70

3-D topography simulator (3-D MULSS) based on a physical description of material topography  

Microsoft Academic Search

This paper presents a three-dimensional (3-D) topography simulator (3-D MULSS), and its applications. We focus on the description of the material surface and the algorithm of the surface advancement. Then we propose a 3-D topography simulation algorithm, with consideration of the probe size of observation, and based on the integration formula of the balance equation. Next, we show the simulation

Masato Fujinaga; Norihiko Kotani

1997-01-01

71

Ice sheet motion and topography from radar interferometry  

Microsoft Academic Search

Both topography and motion information are present in repeat pass ERS-1 interferograms over ice sheets. The authors demonstrate that the topography is separable from the surface displacement field when a sequence of radar images are available. If the velocity field is constant over the time span of observation, the topography can be derived from differential interferograms formed from sequential observations.

Ronald Kwok; Mark A. Fahnestock

1996-01-01

72

Wettability influences cell behavior on superhydrophobic surfaces with different topographies  

Microsoft Academic Search

Surface wettability and topography are recognized as critical factors influencing cell behavior on biomaterials. So far only few works have reported cell responses on surfaces exhibiting extreme wettability in combination with surface topography. The goal of this work is to study whether cell behavior on superhydrophobic surfaces is influenced by surface topography and polymer type. Biomimetic superhydrophobic rough surfaces of

B. N. Lourenco; G. Marchioli; W Song; R. L. Reis; Blitterswijk van C. A; H. B. J. Karperien; Apeldoorn van A. A; J. F. Mano

2012-01-01

73

Systematic error in topography-controlled groundwater models  

Microsoft Academic Search

The topography is often used as a boundary condition in groundwater flow models. This boundary condition is only valid if the groundwater table is a subdued exact replica of the topography. Since the water table never follows the topography exactly, applying this boundary condition induces a systematic error that overestimates the velocities of the top part of the saturated subsurface.

L. Marklund; A. Worman

2008-01-01

74

Feasibility of Intraoperative Corneal Topography Monitoring During Photorefractive Keratectomy  

Microsoft Academic Search

PURPOSE: We propose a feasibility study of new corneal topography technology with the aim of monitoring intraoperative corneal topography dur- ing excimer laser photorefractive keratectomy. The PAR system measures corneal topography with sin- gle grid projection and triangulation but requires fluorescent fluid to be deposited on the corneal sur- face for shape extraction. We propose and demon- strate a novel

Christophe Moser; Juergen Kampmeier; Peter McDonnell; D. Psaltis

75

Volumetric subduction and kinematically driven models of dynamic topography in Southeast Asia  

NASA Astrophysics Data System (ADS)

Southeast Asia has been dominated by accretion of continental terranes and subduction around its main margins for much of the Cenozoic and Mesozoic. It is thus expected that the geological record displays some evidence of subduction-driven dynamic topography signal through anomalous long-wavelength subsidence or uplift in the region. The spatio-temporal patterns and total amplitudes of such dynamic topography component remain controversial. Due to the tectonic complexity of the area, untangling the mantle driven component of vertical motions from isostatic and flexural causes requires synthesis of modelled and observed data. Current forward modelling approaches based on subduction history tend to overpredict vertical motions by an order of magnitude. Forward models are sensitive to plate kinematic errors, such as incorrectly calculated plate velocities and directions, leading to potentially large errors in model output. These models are also dependant on access to high performance computing, making repetitive model runs time and resource prohibitive. The time-dependent volume of downwelling material in the mantle is determined by plate convergence rates and lithospheric thickness along subduction zones. We present a novel workflow to calculate the volume, distribution and shape of subducted slabs from global kinematic and oceanic age reconstructions. Since convective flow within the mantle is mainly driven by density heterogeneities approximated by these slabs, a simple model of the lithosphere-mantle interaction controlled by their buoyancy, viscous resistance to deformation, and mantle drag is able to produce estimations of dynamic topography. Implicit in this workflow is a way to detect anomalous velocities and plate motion directions from predictions based on slab pull and suction. We analyse the history of subducted volumes from 200 Ma to present day. Furthermore we generate present day dynamic topography based on kinematic history. We focus our analysis on the major subduction zones of Southeast Asia and examine the time dependence and amplitudes of volumetric subduction. By computing residual topography we attempt to quantify present day dynamic topography. We also use this approach to investigate vertical motions from 50-45 Ma in the Sunda shelf, where mantle driven subsidence/uplift has been proposed due to the presence of a large unconformity potentially related to a dynamic topography low. Our workflow allows quick quality control on plate kinematic models and allows dynamic topography amplitudes and their spatio-temporal distribution to be further investigated without the need of high performance computing.

Talsma, A. S.; Quevedo, L. E.; Heine, C.; Müller, R. D.

2011-12-01

76

Curvature sensor for the measurement of the static corneal topography and the dynamic tear film topography in the human eye  

NASA Astrophysics Data System (ADS)

A system to measure the topography of the first optical surface of the human eye noninvasively by using a curvature sensor is described. The static corneal topography and the dynamic topography of the tear film can both be measured, and the topographies obtained are presented. The system makes possible the study of the dynamic aberrations introduced by the tear film to determine their contribution to the overall ocular aberrations in healthy eyes, eyes with corneal pathologies, and eyes wearing contact lenses.

Gruppetta, Steve; Koechlin, Laurent; Lacombe, François; Puget, Pascal

2005-10-01

77

Generation of Solitary Rossby Waves by Unstable Topography  

NASA Astrophysics Data System (ADS)

The effect of topography on generation of the solitary Rossby waves is researched. Here, the topography, as a forcing for waves generation, is taken as a function of longitude variable x and time variable t, which is called unstable topography. With the help of a perturbation expansion method, a forced mKdv equation governing the evolution of amplitude of the solitary Rossby waves is derived from quasi-geostrophic vorticity equation and is solved by the pseudo-spectral method. Basing on the waterfall plots, the generational features of the solitary Rossby waves under the influence of unstable topography and stable topography are compared and some conclusions are obtained.

Yang, Hong-Wei; Yin, Bao-Shu; Dong, Huan-He; Ma, Zhen-Dong

2012-03-01

78

The effect of topography on SAR calibration  

SciTech Connect

During normal synthetic aperture radar (SAR) processing, a flat earth is assumed when performing radiometric corrections such as antenna pattern and scattering area removal. Here the authors examine the effects of topographic variations on these corrections. Local slopes will cause the actual scattering area to be different from that calculated using the flat earth assumption. It is shown that this effect, which is present for both airborne and spaceborne SAR data, may easily cause calibration errors larger than a decibel. Ignoring the topography during antenna pattern removal is expected to be negligible for spaceborne SAR's. In this paper they show how these effects can be taken into account if a digital elevation model is available for the imaged area. It is also shown that not taking the topography into account during antenna pattern removal introduces polarimetric calibration errors.

Zyl, J.J. van; Chapman, B.D.; Dubois, P. (California Inst. of Tech., Pasadena, CA (United States). Jet Propulsion Lab.); Shi, Jiancheng (Univ. of California, Santa Barbara, CA (United States))

1993-09-01

79

Karst Topography: Teacher's Guide and Paper Model  

NSDL National Science Digital Library

This lesson uses paper models to help students understand karst processes, why caves develop in limestone, and how karst topography develops. Introductory materials explain how ground- or surface waters can dissolve limestone, some features of karst landscapes (sinkholes, disappearing streams), and some features of caves (stalagmites, stalactites, flowstone). A teacher's guide provides patterns and instructions for building the models, and a glossary and references are included.

80

Impacts of Topography on Sea Level Change  

NSDL National Science Digital Library

This lesson is comprised of three activities (three class periods). Students use web-based animations to explore the impacts of ice melt and changes to sea level. Students are introduced to topographic maps by doing a hands-on activity to model the contours of an island. Students examine the relationship between topography and sea level change by mapping changing shorelines using a topographic map.

Whitfield, Lise; Mcmillon, Bill; Scotchmoor, Judy; Stoffer, Phil; DLESE (Digital Library for Earth System Education)

81

Diffraction imaging (topography) with monochromatic synchrotron radiation  

SciTech Connect

Structural information of special interest to crystal growers and device physicists is now available from high resolution monochromatic synchrotron diffraction imaging (topography). In the review, the importance of superior resolution in momentum transfer and in space is described, and illustrations are taken from a variety of crystals: gallium arsenide, cadmium telluride, mercuric iodide, bismuth silicon oxide, and lithium niobate. The identification and understanding of local variations in crystal growth processes are shown. Finally, new experimental opportunities now available for exploitation are indicated.

Steiner, B.; Kuriyama, M.; Dobbyn, R.C.; Laor, U.

1988-01-01

82

Mercury and Vesta - Preliminary shape and topography  

NASA Astrophysics Data System (ADS)

This year two spacecraft, MESSENGER and Dawn, were placed into orbit around Mercury and the asteroid Vesta, respectively. We have been using stereophotoclinometry (SPC) to analyze MESSENGER and Dawn images both for navigation and to determine the precise shapes and topography of these bodies. Because SPC requires images at different local Sun elevations and azimuths to distinguish between albedo and topographic variations, Mercury presents the challenges of a slow spin rate and a long solar day. Vesta, on the other hand, rotates more than four times per Earth day, allowing a given area of surface to be viewed under rapidly changing illumination and topographic information to be built up rapidly. The essence of SPC is that small pieces of surface called maplets and modeled with digital elevation and albedo are illuminated and correlated with images. Hundreds of these maplets are found in each image, providing a valuable data type for spacecraft navigation. Hundreds of images go into the construction of each maplet, and the resulting multi-image stereo over a wide range of viewing conditions provides a precise determination of the maplet's body-fixed position. The construction of topography with SPC uses each pixel, allowing resolutions comparable to the images themselves. Mercury's topography varies by about 5 km above and below that of a sphere of radius 2440 km. We compare the SPC-derived shape and topography with data from MESSENGER's Mercury Laser Altimeter (MLA). Vesta, although a tenth of Mercury's size, exhibits variations in elevation between 17 km below and 12 km above the equipotential that best matches its surface. The lowest areas lie on the floor of the south polar impact crater, and the highest points lie on the crater's rim.

Gaskell, R. W.; Palmer, E. E.; Mastrodemos, N.; Barnouin, O. S.; Jorda, L.; Taylor, A. H.

2011-12-01

83

Long wave interaction over varying topography  

Microsoft Academic Search

The propagation of long waves on the surface of a three-dimensional fluid domain bounded below by slowly varying topography is considered. There are two important limits: If the initial data can be written in terms of a discrete set of one-dimensional wavefronts, the resulting wave field is described by a set of variable coefficient Korteweg-de Vries (KdV) equations for each

P. Milewski

1998-01-01

84

EAARL Topography-Padre Island National Seashore  

USGS Publications Warehouse

This Web site contains 116 Lidar-derived bare earth topography maps and GIS files for Padre Island National Seashore-Texas. These Lidar-derived topography maps were produced as a collaborative effort between the U.S. Geological Survey (USGS) Florida Integrated Science Center (FISC) St. Petersburg, Florida, the National Park Service (NPS) Gulf Coast Network, Inventory and Monitoring Program, and the National Aeronautics and Space Administration (NASA) Wallops Flight Facility. One objective of this research is to create techniques to survey coral reefs and barrier islands for the purposes of geomorphic change studies, habitat mapping, ecological monitoring, change detection, and event assessment. As part of this project, data from an innovative instrument under development at the NASA Wallops Flight Facility, the NASA Experimental Airborne Advanced Research Lidar (EAARL) are being used. This sensor has the potential to make significant contributions in this realm for measuring subaerial and submarine topography wthin cross-environment surveys. High spectral resolution, water-column correction, and low costs were found to be key factors in providing accurate and affordable imagery to costal resource managers.

Brock, John C.; Wright, C. Wayne; Nayegandhi, Amar; Patterson, Matt; Wilson, Iris; Travers, Laurinda J.

2007-01-01

85

Reconstructing ancient topography through erosion modelling  

NASA Astrophysics Data System (ADS)

One of the main aims of geomorphology is to understand how geomorphic processes change topography over long time scales. Over the last decades several landscape evolution models have been developed in order to study this question. However, evaluation of such models has often been very limited due to the lack of necessary field data. In this study we present a topography based hillslope erosion and deposition model that is based on the WATEM/SEDEM model structure and works on a millennial time scale. Soil erosion, transport and deposition are calculated using slope and unit contributing area. The topography is iteratively rejuvenated by taking into account modelled erosion and deposition rates, thereby simulating topographic development backwards in time. A first attempt has been made to spatially evaluate the model, using detailed estimates for historical soil erosion and sediment deposition volumes, obtained from an augering campaign in a small catchment in the Belgian Loess Belt. The results show that the model can simulate realistic soil redistribution patterns. However, further research is necessary in order to deal with artificial flaws that cause routing problems and significantly influence results. Common problems and issues related to this type of backward modelling are also discussed.

Peeters, Iris; Rommens, Tom; Verstraeten, Gert; Govers, Gerard; van Rompaey, Anton; Poesen, Jean; van Oost, Kristof

2006-08-01

86

TOPOAFRICA project: reconstruction and quantification of the past topography of Africa over the last 250 My.  

NASA Astrophysics Data System (ADS)

The goal of this project is to quantify the growth of long wavelength (x1000 km) topography over the last 250 My at the scale of a continent - Africa - and to understand (1) their relationship with the underlying mantle dynamics over such a time period and (2) their consequence over some Earth surface processes. Most studies of past topography reconstruction have focused on orogenic areas. Few efforts have been devoted to characterizing the more subtle long wavelength topography, such as the doming or plateau uplift of continental areas at the 1000 km wavelength, with a paleoelevation of few hundreds of meters to a maximum of 1000-2000m. A direct inversion of the geological data into estimates of paleotopography is difficult. Quantification of past topographies of a continent requires coupling of geological data with a sediment production (erosion) and transport numerical model. The quantification of the Meso-Cenozoic topographies of the African continent is based on uplift (mean time interval 10 my) and paleoprecipitation maps (input of the model) and siliciclastic sedimentary fluxes and thermochronological data. One of the advance of this project is to draw new-style paleogeographic reconstructions focussed on the continental environments yielding the geometry of paleocatchments, the lacustrine baselevel, the type and the flow direction of the fluvial systems… All those data are registered in database and GIS (ArcGis). Uncertainties are quantified. The uplift maps, in a first step semi-quantitative, are based on the paleogeographical changes and on synthesis of the tectonically induced-unconformities both onland and offhore (seismic) and their consequences (incised valleys, forced-regression wedges, changes of weathering types….). The paleoprecipitation maps are product by coupling climatic numerical models with a geological database (GIS) including all the climate recorders (lithology, type of clays, paleosoils; woods, pollens…). The measure of the siliciclastic sediment flux is based on a geometrical, chronostratigraphical and lithological synthesis of the peri-African (margins) and intra-African (SAG) basins. The thermochronological database is a compilation of all the data available in Africa, plus some new field collections. The new numerical model of sediment production and transport at the continental scale, TOPOSED, will form the basis of the quantitative inversion of the geological data to yield estimates of past topography. Its original aspect consists in investigating separately erosion and transport processes, and in assuming that both are controlled by slope and discharge. Studied time interval: Triassic (Induan, Ladinian, Norian), Jurassic (Sinemurian, Bajocian, Late Kimmeridgian), Cretaceous (Valanginian, Barremian, Middle Aptian, Lower to Middle Albian, Late Cenomanian, Late Coniacian-Early Santonian, Maastrichtian), Paleogene (Thanetian, Lutetian, Chattian), Neogene (Early Miocene, Early Pliocene).

Guillocheau, François

2010-05-01

87

Vacillating jets: baroclinic turbulence and topography  

NASA Astrophysics Data System (ADS)

Observations from satellite altimetry and output from high-resolution ocean models indicate that the Southern Ocean is characterised by an intricate web of narrow, meandering, filamentary jets. These jets undergo spontaneous formation, merger and splitting events, and rapid latitude shifts over periods of weeks to months. The role of topography in controlling jet variability is explored using a doubly-periodic, forced-dissipative, two-layer quasi-geostrophic model. The system is forced by a baroclinically-unstable, vertically-sheared mean flow in a domain that is large enough to accommodate multiple jets. The dependence of (i) meridional jet spacing, (ii) time scales of jet variability and (iii) large-scale, domain-averaged transport properties on changes in the length scale and steepness of simple sinusoidal topographical features is analysed. The Rhines scale ?? measures the meridional extent of eddy mixing by a single jet, and the ratio ??/?T, where ?T is the topographic length scale, determines jet behaviour. Multiple, steady jets with fixed meridional spacing are observed when ?? ? ?T or when ?? ? ?T. However when ?? < ?T, a pattern of perpetual jet formation and jet merger dominates the time evolution of the system. This unsteady structure significantly alters the large-scale energetics and transport properties, leading to a reduction in transport by a factor of two if the topography consists of zonally-invariant ridges, and an increase in transport by an order of magnitude or more if the topography consists of two-dimensional sinusoidal bumps. For certain parameters, bumpy topography gives rise to periodic oscillations in jet structure between purely-zonal and topographically-steered states. In these cases, transport is dominated by bursts of mixing associated with the shifts between the two regimes. Unsteady jet behaviour depends crucially on the feedback between changes in mean flow orientation, caused by topographic steering, and the conversion of potential energy to kinetic energy through baroclinic instability, as well as on asymmetric Reynolds stresses created by topographical modifications to the large-scale potential vorticity gradient. It is likely that these processes play a role in the dynamic nature of Southern Ocean jets.

Thompson, A. F.

2009-04-01

88

Measurement of the topography of human cadaver lenses using the PAR corneal topography system  

NASA Astrophysics Data System (ADS)

To measure the radius of curvature and asphericity of the anterior and posterior surfaces of crystalline lenses of human Eye-Bank eyes using the PAR Corneal Topography System. The measured values will be used in an optical model of the eye for lens refilling procedures.

Fernandez, Viviana; Manns, Fabrice; Zipper, Stanley; Sandadi, Samith; Hamaoui, Marie; Tahi, Hassan; Ho, Arthur; Parel, Jean-Marie A.

2001-06-01

89

Evaluation of facial palsy by moire topography  

NASA Astrophysics Data System (ADS)

To evaluate facial nerve function, the visual assessment method proposed by the Japan Society of Facial Research is used frequently. It is of great value clinically, but the method has several weak points concerning objective and quantitative assessment. This study uses moire topography to solve these problems. mA moire camera, FM3013, of the lattice irradiation type was used for measurement of the face. Five moire photographs were taken: at rest, wrinkling the forehead, closing the eyes lightly, blowing out the cheeks and grinning. The degree of facial palsy was determined by the Asymmetry Index (AI) as a measure of the degree of facial deviation. Total AI was expressed as the average AI based on calculations of the measurement in 5 photos. Severe paralysis is represented by an AI of more than 20%. Partial paralysis has a range of 20-8%. Nearly normal is judged to be less than 8%. Ten normal individuals are measured as control and show an AI of 3% or less. Moire topography is useful in assessing the recovery process because it has the benefit of making the site and grade of palsy easily achieved by the AI and the deviation in its patterns. The authors propose that the moire method is better for an objective and quantitative evaluation than the society's method.

Inokuchi, Ikuo; Kawakami, Shinichiro; Maeta, Manabu; Masuda, Yu

1991-08-01

90

X-Ray Topography of Semiconductor Silicon.  

NASA Astrophysics Data System (ADS)

Available from UMI in association with The British Library. Requires signed TDF. This thesis describes the examination and characterisation of semiconductor silicon by the various methods of X-Ray Diffraction Topography. A brief introduction is given to the dynamical theory of X-ray diffraction and its relevance to the formation of contrast in X-ray topographs. The experimental methods used and contrast formation mechanisms are introduced. The design and construction of an inexpensive Automated Bragg Angle Controller (ABAC) is described, based around a microcomputer and using many of the existing features of the Lang camera. This enables Lang topographs of the whole of distorted crystals to be taken. Using the ABAC, the contrast of defects in Lang topographs of cylindrically bent silicon wafers is explored. A comparison is made between this data and images in Hirst topographs and contrast differences between the techniques are attributed to the presence of an inhomogeneous bending moment. The change in contrast in section and Lang topographs upon homogeneous bending for asymmetric reflections is also investigated and mechanisms for the contrast changes are suggested. A bipolar device wafer is examined with double crystal topography using synchrotron radiation and a highly asymmetric reflection with a glancing angle of incidence. By exploiting the wavelength tuneability of the synchrotron radiation, the depth penetration of the X-rays is varied and the optimum experimental conditions for observing both defects and devices determined. Using this technique it is possible to image both devices and process related defects to a high resolution and contrast. The Lang, section and glancing angle double crystal topography techniques are compared for the examination of a CMOS device wafer. The relative strengths and weaknesses of each technique are highlighted and many defects are imaged and characterised. Finally, results showing the appearance of fringes in the double crystal topographs for low angles of incidence are presented. These are attributed to the presence of a long range strain, and the dependence of the fringes upon curvature is explored for moderate bending conditions (R ~ 35m).

Loxley, Neil

91

Phase transition Clapeyron slopes and transition zone seismic discontinuity topography  

Microsoft Academic Search

The depths, widths, and magnitudes of the 410-km and 660-km seismic discontinuities are largely consistent with an isochemical phase change origin, as is the observation that the topography on these discontinuities is negatively correlated and significantly smaller than predicted for chemical changes. While most thermodynamic studies of the relevant phase changes predict greater topography on the 410 than the 660,

Craig R. Bina; George Helffrich

1994-01-01

92

Percolation, statistical topography, and transport in random media  

Microsoft Academic Search

A review of classical percolation theory is presented, with an emphasis on novel applications to statistical topography, turbulent diffusion, and heterogeneous media. Statistical topography involves the geometrical properties of the isosets (contour lines or surfaces) of a random potential Ï({bold x}). For rapidly decaying correlations of Ï, the isopotentials fall into the same universality class as the perimeters of percolation

M. Isichenko

1992-01-01

93

Data combination in topography measurement of revolving objects  

Microsoft Academic Search

Several photos of projected gratings patterns should be taken from different angles, when 3D topography of revolving objects is measured by grating projected method. How to combine the measured data of grating projected patterns is a key factor of measuring 3D topography of revolving objects. A new data combination method, which is based on cylinder coordinate transform, is proposed in

Yun Han; Li Ma; Shiping He; Lang Liu

2003-01-01

94

Surface Topography of Symmetric and Asymmetric Polyolefin Block Copolymer Films  

Microsoft Academic Search

Finite film thickness constraints result in the formation of islands and holes on the surface of block copolymer films when the film thickness deviates from a conformal number of layers. This paper describes a comprehensive study of surface topography in model polyolefin diblock copolymers. We present results on the evolution of surface topography from the spun cast state, changes in

Navjot Singh; Andrew Kudrle; Mohan Sikka; Frank S. Bates

1995-01-01

95

Smoking topography and trajectory of asthmatic adolescents requesting cessation treatment  

Microsoft Academic Search

Background. Teenage smokers cite health concerns as their primary motivators for tobacco smoking cessation. Smoke exposure aggravates the clinical course of asthma, yet few reports have examined the association between asthma and smoking topography and trajectory.Methods. Before their enrollment in a smoking cessation trial, we assessed the smoking topography (i.e., puff volume, maximum puff velocity, puff duration, and interpuff interval)

Darin M. Zimmerman; Shelley S. Sehnert; David H. Epstein; Wallace B. Pickworth; Miqun L. Robinson; Eric T. Moolchan

2004-01-01

96

Cokriging surface elevation and seismic refraction data for bedrock topography  

SciTech Connect

Analysis of seismic refraction data collected at a proposed site of the Advanced Neutron Source (ANS) Facility showed a strong correlation between surface and bedrock topography. By combining seismically determined bedrock elevation data with surface elevation data using cokriging, we were able to significantly improve our map of bedrock topography without collecting additional seismic data.

Nyquist, J.E.; Doll, W.E. (Oak Ridge National Lab., TN (United States)); Davis, R.K. (Automated Sciences Group, Inc., Oak Ridge, TN (United States)); Hopkins, R.A. (Marrich, Inc., Knoxville, TN (United States))

1992-01-01

97

Cokriging surface elevation and seismic refraction data for bedrock topography  

SciTech Connect

Analysis of seismic refraction data collected at a proposed site of the Advanced Neutron Source (ANS) Facility showed a strong correlation between surface and bedrock topography. By combining seismically determined bedrock elevation data with surface elevation data using cokriging, we were able to significantly improve our map of bedrock topography without collecting additional seismic data.

Nyquist, J.E.; Doll, W.E. [Oak Ridge National Lab., TN (United States); Davis, R.K. [Automated Sciences Group, Inc., Oak Ridge, TN (United States); Hopkins, R.A. [Marrich, Inc., Knoxville, TN (United States)

1992-11-01

98

Large Eddy Simulation over three-dimensional mountain topography  

Microsoft Academic Search

A new generation Large-Eddy Simulation (LES) is applied to study wind fields and the influence of local topography. In this study we focus on the implementation of three-dimensional topography in our LES algorithm using an immersed boundary method. To validate the model, the LES results are compared with measurements from wind tunnel studies taken from the literature. The code is

M. Diebold; C. Higgins; M. Lehning; E. Bou-Zeid; M. B. Parlange

2010-01-01

99

Spectral analysis of the gravity and topography of Mars  

Microsoft Academic Search

New spherical harmonic models of the gravity and topography of Mars place important constraints on the structure and dynamics of the interior. The gravity and topography models are significantly phase coherent for harmonic degrees n less than 30 (wavelengths greater than 700 km). Loss of coherence below that wavelength is presumably due to inadequacies of the models, rather than a

Bruce G. Bills; Herbert V. Frey; Walter S. Kiefer; R. Steven Nerem; Maria T. Zuber

1993-01-01

100

Forecasting Hurricane Impact on Coastal Topography  

NASA Astrophysics Data System (ADS)

Extreme storms can have a profound impact on coastal topography and thus on ecosystems and human-built structures within coastal regions. For instance, landfalls of several recent major hurricanes have caused significant changes to the U.S. coastline, particularly along the Gulf of Mexico. Some of these hurricanes (e.g., Ivan in 2004, Katrina and Rita in 2005, and Gustav and Ike in 2008) led to shoreline position changes of about 100 meters. Sand dunes, which protect the coast from waves and surge, eroded, losing several meters of elevation in the course of a single storm. Observations during these events raise the question of how storm-related changes affect the future vulnerability of a coast.

Plant, Nathaniel G.; Stockdon, Hilary F.; Sallenger, Asbury H.; Turco, Michael J.; East, Jeffery W.; Taylor, Arthur A.; Shaffer, Wilson A.

2010-02-01

101

The Role of Topography in Glacial Inception  

NASA Astrophysics Data System (ADS)

We test the influence of model topography on glacial inception using a coupled atmosphere-slab ocean version of NCAR’s Community Climate System Model (CCSM3). Simulations employ a modern orbital configuration and greenhouse gas concentrations representing both recent (year 1990) and hypothetically lower present-day values in accordance with Ruddiman’s Early Anthropogenic Hypothesis (240 ppm CO2 and 450 ppb CH4). The model is run at two different resolutions: a relatively coarse horizontal configuration (T42, approximately 2.8 degrees) and comparatively fine resolution (T85, approximately 1.4 degrees). Although under contemporary greenhouse forcing the extent of permanent boreal snow cover in the two model configurations is similar, imposing lower concentrations of CO2 and CH4 generates much more extensive glacial inception in the T85 experiment (150% increase) than in the T42 version (80% increase). Furthermore, the spatial patterns of glacial inception differ considerably. Only the T85 resolution produces widespread permanent snow cover over the Rocky Mountains and on Baffin Island, consistent with geologic evidence for ice sheet nucleation in northeastern Canada. Although much of the enhanced sensitivity in the higher-resolution simulations is directly attributable to the colder and wetter conditions around elevated topography, some of the response also appears to be driven dynamically and remotely as a function of the simulated elevation of Greenland. The colder conditions over and downstream of the Greenland Ice Sheet in the modern T85 simulation promote a smaller cooling locally under lowered greenhouse forcing that seems to activate a wave-1 dynamical response in the atmospheric pressure field. The resulting circulation anomalies favor stronger upslope wind flow from the Pacific Ocean over the northern Rocky Mountains, enhancing the regional development of a permanent snow pack. Although these experiments are driven by greenhouse forcing rather than historical orbital variations, we believe that our findings apply to the general mechanisms of glacial inception.

Vavrus, S. J.; Philippon-Berthier, G.; Kutzbach, J. E.; Ruddiman, W. F.

2009-12-01

102

Surface Water and Ocean Topography (SWOT) mission  

NASA Astrophysics Data System (ADS)

The Surface Water Ocean Topography (SWOT) mission was recommended in 2007 by the National Research Council's Decadal Survey, "Earth Science and Applications from Space: National Imperatives for the Next Decade and Beyond", for implementation by NASA. The SWOT mission is a partnership between two communities, the physical oceanography and the hydrology, to share high vertical accuracy and high spatial resolution topography data produced by the science payload, principally a Ka-band radar Interferometer (KaRIn). The SWOT payload also includes a precision orbit determination system consisting of GPS and DORIS receivers, a Laser Retro-reflector Assembly (LRA), a Jason-class nadir radar altimeter, and a JASON-class radiometer for tropospheric path delay corrections. The SWOT mission will provide large-scale data sets of ocean sea-surface height resolving scales of 15km and larger, allowing the characterization of ocean mesoscale and submesoscale circulation. The SWOT mission will also provide measurements of water storage changes in terrestrial surface water bodies and estimates of discharge in large (wider than 100m) rivers globally. The SWOT measurements will provide a key complement to other NASA spaceborne global measurements of the water cycle measurements by directly measuring the surface water (lakes, reservoirs, rivers, and wetlands) component of the water cycle. The SWOT mission is an international partnership between NASA and the Centre National d'Etudes Spatiales (CNES). The Canadian Space Agency (CSA) is also expected to contribute to the mission. SWOT is currently nearing entry to Formulation (Phase A). Its launch is targeted for October 2020.

Neeck, Steven P.; Lindstrom, Eric J.; Vaze, Parag V.; Fu, Lee-Lueng

2012-09-01

103

Evaluation of the PAR corneal topography system  

NASA Astrophysics Data System (ADS)

The purpose of this study was to evaluate the raster photogrammetry based Corneal Topography System by determining: inter-operator variability, reproducibility of images, effects of defocused and decentered images, and the precision of data at different optical zones. 4 human cadaver eyes were used to study the inter-operator variability. To study the reproducibility of images, 3 human cadaver eyes and a test surface doped with flourescine (provided by PAR Vision Systems Corporation) were focused and their images taken four successive times. Defocused and decentered images were taken of 4 human cadaver eyes and four times of the test surface mentioned above. The precision of defocused/decentered cadaver eyes was evaluated at the following optical zones: 3 mm, 4 mm, 5 mm, and 6 mm. All human cadaver eyes used in the above experiments had their epithelial layer removed before imaging. Average inter-operator variability was 0.06 D. In reproducibility attempts, there was an average deviation of 0.28 D for the human cadaver eyes and 0.04 D for the test surface. The defocused and decentered test surface gave an average deviation of 0.09 D. Defocused and decentered cadaver eyes resulted in an average deviation of 0.52 D, 0.37 D, 0.24 D, and 0.22 D at optical zones of 3 mm, 4 mm, 5 mm, and 6 mm, respectively. The imaging method employed by PAR Vision Systems Corporation virtually eliminates inter-operator variability. The PAR Corneal Topography System's clinical usefulness, however, could be improved by improving the reproducibility of images, decreasing the sensitivity to spatial alignment, and increasing accuracy over smaller optical zones.

Jindal, Prateek; Cheung, Susan; Pirouzian, Amir; Keates, Richard H.; Ren, Qiushi

1995-05-01

104

Episodic growth of topography in eastern Tibet  

NASA Astrophysics Data System (ADS)

High topography associated with the eastern portions of the Tibetan Plateau is thought to have developed as eastward flow of deep crust from beneath central Tibet drove crustal thickening and attendant surface uplift along the periphery of the plateau. The onset of rapid Late Miocene exhumation (ca. 10-15 Ma) in deep canyons of eastern Tibet is inferred to herald surface uplift which enabled rapid fluvial incision and the development of high topographic relief. Although consistent with geophysical data, this model struggles to explain the timing and amount of Cenozoic shortening adjacent to the Sichuan Basin. Here we report cooling histories of rocks currently exposed along a ~3 km vertical section adjacent to the Sichuan Basin derived from multiple low-temperature thermochronologic systems including apatite and zircon fission-track and (U-Th)/He. Our results reveal that this margin of the plateau was subject to slow, steady exhumation during early Cenozoic time, requiring that limited topographic relief (<1000m) was present prior to initial collision of India and Asia. Moreover, thermal models of exhumation-driven cooling demonstrate that subsequent exhumation of >10 km occurred in two temporally-distinct episodes, during Oligocene (~30-25 Ma) and Late Miocene (~10-15 Ma) time, separated by a hiatus of at least 10 Ma. These results challenge the notion that the plateau in eastern Tibet developed as a singular consequence of lower crustal flow. Rather, our findings require a punctuated history of mountain building that potentially reconciles conflicting models for relative roles of upper crustal shortening and lower crustal flow in the development of topography adjacent to the Sichuan Basin.

Kirby, E.; Furlong, K.; Wang, E.; Shi, X.; van Soest, M.; Xu, G.; Kamp, P.; Hodges, K.

2012-04-01

105

Bedrock topography beneath the Red Lake peatlands  

SciTech Connect

Detailed hydrologic investigations of peat landforms in the Red Lake Peatlands have revealed that groundwater flow is significantly related to the type of landform and vegetation community present at a given site. Hydrogeologic modeling of shallow groundwater systems suggests that bedrock topography is an important, perhaps the vital, boundary condition controlling groundwater flow. Determination of depth to bedrock beneath different peat landforms is necessary to test the hydrogeologic models and obtain a better understanding of the processes which produce them. Direct determination of bedrock depth in peatlands is hampered by the difficult conditions and high costs of boring. In addition, environmental impacts from boring activities would probably be substantial in these sensitive ecosystems. Shallow seismic methods appear to be the most promising approach to obtain the necessary data. Unfortunately the 2+ meters of peat covering Lake Agassiz sediments overlying the bedrock is not only a poor substrate for geophone emplacement, but is a strong attenuator of seismic waves. These difficulties have been overcome by constructing a tool which allows the geophones to be emplaced beneath the peat and into the top of the sediments. The shotgun cartridge source is also located beneath the peat. This combination results in very good seismic records, far better than those possible with surface sources and geophones. The results from a preliminary survey along a 600m line show that there are significant variations in bedrock topography below the peat. In a distance of less than 500m, depth to bedrock changes by about 30%, from about 55m to about 40m. This is similar to variations indicated by the models.

Miller, P.; Shaw, G.H. (Union Coll., Schenectady, NY (United States). Geology Dept.); Glaser, P. (Univ. of Minnesota, Minneapolis, MN (United States). Limnological Research Center); Siegel, D. (Syracuse Univ., NY (United States). Dept. of Geology)

1992-01-01

106

An Assessment of Topography Measurements on Europa  

NASA Astrophysics Data System (ADS)

Many small patches of chaotic terrain on Europa appear to be bulged upward, giving qualitative impressions that chaos might represent "cryovolcanic" and/or convective upwelling. The same bulged appearance is explained by the oceanic melt-through model, as simply the topography expected after refreezing and buoyant equilibrium. Greenberg et al. suggested an observational test to discriminate between these models, based on whether the up-bulged chaos is higher than the typical tectonic terrain in the region (for up-welling) or only higher than its immediate moat-like surroundings (melt-through and refreezing). Several authors have taken up this challenge, presenting topographic maps to refute the melt-through model by showing high elevations for chaos. However, details on the methods (based on combinations of stereo images and photoclinometry) have been sketchy, and without quantitative analyses of precision. For example, near Tyre, topographic maps and profiles reportedly show elevated chaos areas. Yet the elevations differ between published results by much more than the purported 10m precision. Moreover, high-elevation portions of profiles that were labeled as chaos are actually tectonic terrain. Stereo actually shows that major chaos areas are lower than the tectonic terrain in the area. Also, variations in elevation within the tectonic terrain are so great that differences from chaotic terrain are in the noise. Moreover, our error-analyses for both stereo and photoclinometry indicate that uncertainties are greater than reported differences between elevations of chaotic and tectonic terrain. For example, stereo-based models may exaggerate the height of chaos by favoring rafts as tie features, and photoclinometry is sensitive to an uncertain photometric function and to sub-pixel slope variations. To paraphrase Mark Twain, reports of the death of the melt-through model have been greatly exaggerated. Any results based on topography should not be accepted until the methods involved have been subjected to rigorous and transparent quantitative evaluation.

Greenberg, Richard; Hurford, T.; Foley, M.

2006-09-01

107

Topography of initiation of N-glycosylation reactions  

SciTech Connect

Previous studies on the topography of the reactions leading to the formation of dolichol-P-P-Glc-NAc2Man9Glc3 have shown that these occur on both sides of the endoplasmic reticulum membrane. Dolichol-P-P-GlcNAc2Man5 has been detected on the cytoplasmic side of the endoplasmic reticulum membrane while the subsequent dolichol-oligosaccharide intermediates face the lumen. Less clear is the side of the membrane where dolichol-P-P-GlcNAc2 is assembled. We now present evidence strongly suggesting that the active sites of the enzymes catalyzing the synthesis of this latter intermediate are on the cytoplasmic side of the endoplasmic reticulum membrane. In addition, dolichol-P-P-GlcNAc2 has also been detected on this side. Incubations of sealed, right side out rat liver endoplasmic reticulum-derived vesicles with (beta-32P) UDP-GlcNAc in the presence of 5-Br-UMP resulted in the formation of radiolabeled dolichol-P-P-GlcNAc and dolichol-P-P-GlcNAc2 under conditions where there was complete inhibition of transport of the nucleotide sugar. In other experiments with the above radiolabeled nucleotide sugar and sealed vesicles, it was demonstrated that EDTA (a membrane-impermeable reagent) inhibited the N-acetylglucosamine-1-phosphate transferase under conditions where transport of the nucleotide sugar into the lumen was unaffected. Finally, sealed vesicles were first incubated with (32P)UDP-GlcNAc and subsequently with UDP-Gal and soluble galactosyltransferase. This resulted in galactosylation of dolichol-P-P-GlcNAc2. The above results, together with the previous observations, strongly suggest that all reactions leading to this latter dolichol intermediate occur on the cytosolic side of the endoplasmic reticulum membrane.

Abeijon, C.; Hirschberg, C.B. (Univ. of Massachusetts Medical Center, Worcester (USA))

1990-08-25

108

Venus topography and kilometer-scale slopes  

NASA Astrophysics Data System (ADS)

During the first 8 months of the Magellan mission, the radar altimeter has made some three million measurements of the surface of Venus covering the latitude range from 85 deg N to 80 deg S. Methods involving range correlation, Doppler filtering, multiburst summation, and range migration are used to focus the observations and to achieve high surface resolution. Results are presented as maps of the global distribution of topography, meter-scale roughness, and power reflection coefficient. The results are similar to those reported in previous experiments (surface heights exhibit a unimodal distribution with more than 80 percent of the surface lying within 1 km of the 6051.84-km mean radius) but the higher resolution of the Magellan altimeter has disclosed several surprisingly steep features, e.g., the southwest face of the Maxwell Montes, the southern face of the Danu Montes, and the chasmata to the east of Thetis Regio, where average kilometer-scale slopes of greater than 30 deg are not uncommon. This conclusion is corroborated by close inspection of synthetic aperture radar imagery.

Ford, Peter G.; Pettengill, Gordon H.

1992-08-01

109

Topography of cerebellar deficits in humans.  

PubMed

The cerebellum is a key-piece for information processing and is involved in numerous motor and nonmotor activities, thanks to the anatomical characteristics of the circuitry, the enormous computational capabilities and the high connectivity to other brain areas. Despite its uniform cytoarchitecture, cerebellar circuitry is segregated into functional zones. This functional parcellation is driven by the connectivity and the anatomo-functional heterogeneity of the numerous extra-cerebellar structures linked to the cerebellum, principally brain cortices, precerebellar nuclei and spinal cord. Major insights into cerebellar functions have been gained with a detailed analysis of the cerebellar outputs, with the evidence that fundamental aspects of cerebrocerebellar operations are the closed-loop circuit and the predictions of future states. Cerebellar diseases result in disturbances of accuracy of movements and lack of coordination. The cerebellar syndrome includes combinations of oculomotor disturbances, dysarthria and other speech deficits, ataxia of limbs, ataxia of stance and gait, as well as often more subtle cognitive/behavioral impairments. Our understanding of the corresponding anatomo-functional maps for the human cerebellum is continuously improving. We summarize the topography of the clinical deficits observed in cerebellar patients and the growing evidence of a regional subdivision into motor, sensory, sensorimotor, cognitive and affective domains. The recently described topographic dichotomy motor versus nonmotor cerebellum based upon anatomical, functional and neuropsychological studies is also discussed. PMID:21240580

Grimaldi, Giuliana; Manto, Mario

2012-06-01

110

Surface topography and rotational symmetry breaking.  

PubMed

The surface electroclinic effect, which is a rotation of the molecular director in the substrate plane proportional to an electric field E applied normal to the substrate, requires both a chiral environment and C(2) (or lower) rotational symmetry about E. The two symmetries typically are created in tandem by manipulating the surface topography, a process that conflates their effects. Here we use a pair of rubbed polymer-coated substrates in a twist geometry to obtain our main result, viz., that the strengths of two symmetries, in this case the rub-induced breaking of C(?) rotational symmetry and chiral symmetry, can be separated and quantified. Experimentally we observe that the strength of the reduced rotational symmetry arising from the rub-induced scratches, which is proportional to the electroclinic response, scales linearly with the induced topographical rms roughness and increases with increasing rubbing strength of the polymer. Our results also suggest that the azimuthal anchoring strength coefficient is relatively insensitive to the strength of the rubbing. PMID:23005441

Basu, Rajratan; Nemitz, Ian R; Song, Qingxiang; Lemieux, Robert P; Rosenblatt, Charles

2012-07-27

111

Surface topography and rotational symmetry breaking  

NASA Astrophysics Data System (ADS)

The surface electroclinic effect, which is a rotation of the molecular director in the substrate plane proportional to an electric field E? applied normal to the substrate, requires both a chiral environment and C2 (or lower) rotational symmetry about E?. The two symmetries typically are created in tandem by manipulating the surface topography, a process that conflates their effects. Here we use a pair of rubbed polymer-coated substrates in a twist geometry to obtain our main result, viz., that the strengths of two symmetries, in this case the rub-induced breaking of C? rotational symmetry and chiral symmetry, can be separated and quantified. Experimentally we observe that the strength of the reduced rotational symmetry arising from the rub-induced scratches, which is proportional to the electroclinic response, scales linearly with the induced topographical rms roughness and increases with increasing rubbing strength of the polymer. Our results also suggest that the azimuthal anchoring strength coefficient is relatively insensitive to the strength of the rubbing.

Basu, Rajratan; Nemitz, Ian R.; Song, Qingxiang; Lemieux, Robert P.; Rosenblatt, Charles

2012-07-01

112

Surface topography and rotational symmetry breaking  

NASA Astrophysics Data System (ADS)

The surface electroclinic effect, which is a rotation of the molecular director in the substrate plane proportional to an electric field applied normal to the substrate, requires both a chiral environment and C2 (or lower) rotational symmetry about the field. The two symmetries typically are created in tandem by manipulating the surface topography, a process that conflates their effects. Here we use a pair of rubbed polymer-coated substrates in a twist geometry to obtain our main result, viz., that the strengths of two symmetries, in this case the rub-induced breaking of C? rotational symmetry and chiral symmetry, can be separated and quantified. Experimentally we observe that the strength of the reduced rotational symmetry arising from the rub-induced scratches, which is proportional to the electroclinic response, scales linearly with the induced topographical rms roughness and increases with increasing rubbing strength of the polymer. Our results also suggest that the azimuthal anchoring strength coefficient is relatively insensitive to the strength of the rubbing.

Basu, Rajratan; Nemitz, Ian; Song, Qingxiang; Lemieux, Robert; Rosenblatt, Charles

2013-03-01

113

The Cortical Topography of Local Sleep  

PubMed Central

In a recent series of experiments, we demonstrated that a visuomotor adaptation task, 12 hours of left arm immobilization, and rapid transcranial magnetic stimulation (rTMS) during waking can each induce local changes in the topography of electroencephalographic (EEG) slow wave activity (SWA) during subsequent non-rapid eye movement (NREM) sleep. However, the poor spatial resolution of EEG and the difficulty of relating scalp potentials to the activity of the underlying cortex limited the interpretation of these results. In order to better understand local cortical regulation of sleep, we used source modeling to show that plastic changes in specific cortical areas during waking produce correlated changes in SWA during sleep in those same areas. We found that implicit learning of a visuomotor adaptation task induced an increase in SWA in right premotor and sensorimotor cortices when compared to a motor control. These same areas have previously been shown to be selectively involved in the performance of this task. We also found that arm immobilization resulted in a decrease in SWA in sensorimotor cortex. Inducing cortical potentiation with repetitive transcranial magnetic stimulation (rTMS) caused an increase in SWA in the targeted area and a decrease in SWA in the contralateral cortex. Finally, we report the first evidence that these modulations in SWA may be related to the dynamics of individual slow waves. We conclude that there is a local, plasticity dependent component to sleep regulation and confirm previous inferences made from the scalp data.

Murphy, Michael; Huber, Reto; Esser, Steve; Riedner, Brady A.; Massimini, Marcello; Ferrarelli, Fabio; Ghilardi, M. Felice; Tononi, Giulio

2011-01-01

114

Moiré topography: characteristics and clinical application.  

PubMed

Since 1970, the Moiré phenomenon has been employed as a method of clinical diagnosis in topographical analyses of the human body. The objective of this study was to review the literature on the main characteristics of the Moiré phenomenon and its use as a topographical method for clinical applications, particularly those related to postural deviations. A systematic search for papers written in English between 1966 and 2010 was performed according to pre-established selection criteria and the selected studies underwent a content analysis. The results showed an evolution in the method of Moiré topography (MT), which reflect an increasing effort to improve the accuracy and precision of the method, as well as to facilitate the interpretation of topograms using specific software. The Shadow and Projection Moiré techniques have more frequently been used in comparison with other techniques. On the other hand, the methodological procedures of MT are apparently not well defined in the literature. Although MT was shown to be useful in the detection of spinal deformities, there is still a lack of research in clinical settings, especially in the elderly. For the most part, the studies involve the tracking of scoliosis in school age children. Japan appears to be the most advanced country in terms of the application of MT. PMID:20643549

Porto, Flávia; Gurgel, Jonas Lírio; Russomano, Thais; Farinatti, Paulo De Tarso Veras

2010-07-01

115

Wettability control by DLC coated nanowire topography.  

PubMed

Here we have developed a convenient method to fabricate wettability controllable surfaces that can be applied to various nanostructured surfaces with complex shapes for different industrial needs. Diamond-like carbon (DLC) films were synthesized on titanium substrate with a nanowire structured surface using plasma immersion ion implantation and deposition (PIII&D). The nanostructure of the DLC films was characterized by field emission scanning electron microscopy and found to grow in a rippling layer-by-layer manner. Raman spectroscopy was used to investigate the different bonding presented in the DLC films. To determine the wettability of the samples, water contact angles were measured and found to vary in the range of 50°-141°. The results indicated that it was critical to construct a proper surface topography for high hydrophobicity, while suitable I(D)/I(G) and sp²/sp³ ratios of the DLC films had a minor contribution. Superhydrophobicity could be achieved by further CF? implantation on suitably structured DLC films and was attributed to the existence of fluorine. In order to maintain the nanostructure during CF? implantation, it was favorable to pre-deposit an appropriate carbon content on the nanostructure, as a nanostructure with low carbon content would be deformed during CF? implantation due to local accumulation of surface charge and the following discharge resulting from the low conductivity. PMID:21343636

Li, Zihui; Meng, Fanhao; Liu, Xuanyong

2011-02-22

116

Wettability control by DLC coated nanowire topography  

NASA Astrophysics Data System (ADS)

Here we have developed a convenient method to fabricate wettability controllable surfaces that can be applied to various nanostructured surfaces with complex shapes for different industrial needs. Diamond-like carbon (DLC) films were synthesized on titanium substrate with a nanowire structured surface using plasma immersion ion implantation and deposition (PIII&D). The nanostructure of the DLC films was characterized by field emission scanning electron microscopy and found to grow in a rippling layer-by-layer manner. Raman spectroscopy was used to investigate the different bonding presented in the DLC films. To determine the wettability of the samples, water contact angles were measured and found to vary in the range of 50°-141°. The results indicated that it was critical to construct a proper surface topography for high hydrophobicity, while suitable ID/IG and sp2/sp3 ratios of the DLC films had a minor contribution. Superhydrophobicity could be achieved by further CF4 implantation on suitably structured DLC films and was attributed to the existence of fluorine. In order to maintain the nanostructure during CF4 implantation, it was favorable to pre-deposit an appropriate carbon content on the nanostructure, as a nanostructure with low carbon content would be deformed during CF4 implantation due to local accumulation of surface charge and the following discharge resulting from the low conductivity.

Li, Zihui; Meng, Fanhao; Liu, Xuanyong

2011-04-01

117

Basins of attraction on random topography  

SciTech Connect

We investigate the consequences of fluid flowing on a continuous surface upon the geometric and statistical distribution of the flow. We find that the ability of a surface to collect water by its mere geometrical shape is proportional to the curvature of the contour line divided by the local slope. Consequently, rivers tend to lie in locations of high curvature and flat slopes. Gaussian surfaces are introduced as a model of random topography. For Gaussian surfaces the relation between convergence and slope is obtained analytically. The convergence of flow lines correlates positively with drainage area, so that lower slopes are associated with larger basins. As a consequence, we explain the observed relation between the local slope of a landscape and the area of the drainage basin geometrically. To some extent, the slope-area relation comes about not because of fluvial erosion of the landscape, but because of the way rivers choose their path. Our results are supported by numerically generated surfaces as well as by real landscapes.

Schorghofer, Norbert; Rothman, Daniel H.

2001-02-01

118

Nano-topography sensing by osteoclasts  

PubMed Central

Bone resorption by osteoclasts depends on the assembly of a specialized, actin-rich adhesive ‘sealing zone’ that delimits the area designed for degradation. In this study, we show that the level of roughness of the underlying adhesive surface has a profound effect on the formation and stability of the sealing zone and the associated F-actin. As our primary model substrate, we use ‘smooth’ and ‘rough’ calcite crystals with average topography values of 12 nm and 530 nm, respectively. We show that the smooth surfaces induce the formation of small and unstable actin rings with a typical lifespan of ~8 minutes, whereas the sealing zones formed on the rough calcite surfaces are considerably larger, and remain stable for more than 6 hours. It was further observed that steps or sub-micrometer cracks on the smooth surface stimulate local ring formation, raising the possibility that similar imperfections on bone surfaces may stimulate local osteoclast resorptive activity. The mechanisms whereby the physical properties of the substrate influence osteoclast behavior and their involvement in osteoclast function are discussed.

Geblinger, Dafna; Addadi, Lia; Geiger, Benjamin

2010-01-01

119

Predicting Maximum Lake Depth from Surrounding Topography  

PubMed Central

Information about lake morphometry (e.g., depth, volume, size, etc.) aids understanding of the physical and ecological dynamics of lakes, yet is often not readily available. The data needed to calculate measures of lake morphometry, particularly lake depth, are usually collected on a lake-by-lake basis and are difficult to obtain across broad regions. To span the gap between studies of individual lakes where detailed data exist and regional studies where access to useful data on lake depth is unavailable, we developed a method to predict maximum lake depth from the slope of the topography surrounding a lake. We use the National Elevation Dataset and the National Hydrography Dataset – Plus to estimate the percent slope of surrounding lakes and use this information to predict maximum lake depth. We also use field measured maximum lake depths from the US EPA's National Lakes Assessment to empirically adjust and cross-validate our predictions. We were able to predict maximum depth for ?28,000 lakes in the Northeastern United States with an average cross-validated RMSE of 5.95 m and 5.09 m and average correlation of 0.82 and 0.69 for Hydrological Unit Code Regions 01 and 02, respectively. The depth predictions and the scripts are openly available as supplements to this manuscript.

Hollister, Jeffrey W.; Milstead, W. Bryan; Urrutia, M. Andrea

2011-01-01

120

Shape, Topography and Roughness of 25143 Itokawa  

NASA Astrophysics Data System (ADS)

The recent visit of the Hayabusa spacecraft to the small near-Earth asteroid (NEA) 25143 Itokawa yielded the surprising discovery that Itokawa was not an intact object but a low density, gravitationally accumulated, rubble pile. This contrasts with the finding, from the only other NEA visited by an asteroid lander, that 433 Eros was an intact object and not a rubble pile. Eros was visited by the NEAR Shoemaker spacecraft which landed in 2001. Accurately co-registered, high resolution imager and lidar data from NEAR Shoemaker have demonstrated the fractal properties of small scale surface topography on Eros, where boulders tend to be found on the tops of long ridges, consistent with the presence of an underlying globally coherent structure. However, Itokawa is a rubble pile with a fundamentally different collisional history. Here we analyze co-registered, high resolution lidar and imager data from Itokawa, obtained by Hayabusa, to explore fractal properties and surface roughness distributions on Itokawa for comparison with the results from Eros.

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

2007-12-01

121

Inversion of topography in Martian highland terrains  

SciTech Connect

Ring furrows are flat-floored trenches, circulate in plan view, forming rings 7 to 50 km in diameter. Typically, ring furrows, which are 0.5 km deep and 2 to 10 km wide, surround a central, flat-topped, circular mesa or plateau. The central plateau is about the same elevation or lower than the plain outside the ring. Ring furrows are unique features of the dissected martian uplands. Related landforms range from ring furrows with fractured central plateaus to circular mesas without encircling moats. Ring furrows are superposed on many types of materials, but they are most common cratered plateau-type materials that are interpreted as volcanic flow material overlying ancient cratered terrain. The ring shape and size suggest that they are related to craters partially buried by lava flows. Ring furrows were formed by preferential removal of exposed rims of partially buried craters. Evidence of overland flow of water is lacking except within the channels. Ground ice decay and sapping followed by fluvial erosion are responsible for removal of the less resistant rim materials. Thus, differential erosion has caused a reversal of topography in which the originally elevated rim is reduced to negative relief.

De Hon, R.A.

1985-01-01

122

Predicting maximum lake depth from surrounding topography.  

PubMed

Information about lake morphometry (e.g., depth, volume, size, etc.) aids understanding of the physical and ecological dynamics of lakes, yet is often not readily available. The data needed to calculate measures of lake morphometry, particularly lake depth, are usually collected on a lake-by-lake basis and are difficult to obtain across broad regions. To span the gap between studies of individual lakes where detailed data exist and regional studies where access to useful data on lake depth is unavailable, we developed a method to predict maximum lake depth from the slope of the topography surrounding a lake. We use the National Elevation Dataset and the National Hydrography Dataset - Plus to estimate the percent slope of surrounding lakes and use this information to predict maximum lake depth. We also use field measured maximum lake depths from the US EPA's National Lakes Assessment to empirically adjust and cross-validate our predictions. We were able to predict maximum depth for ?28,000 lakes in the Northeastern United States with an average cross-validated RMSE of 5.95 m and 5.09 m and average correlation of 0.82 and 0.69 for Hydrological Unit Code Regions 01 and 02, respectively. The depth predictions and the scripts are openly available as supplements to this manuscript. PMID:21984945

Hollister, Jeffrey W; Milstead, W Bryan; Urrutia, M Andrea

2011-09-30

123

23. SPILLWAY NO. 1 LOWER END TOPOGRAPHY AND SECTIONS. ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

23. SPILLWAY NO. 1 - LOWER END TOPOGRAPHY AND SECTIONS. February 1934. Reference BS-150. - Cushman No. 1 Hydroelectric Power Plant, Spillway, North Fork of Skokomish River, 5 miles West of Hood Canal, Hoodsport, Mason County, WA

124

2. GENERAL VIEW SHOWING RELATION OF BRIDGE TO THE TOPOGRAPHY ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. GENERAL VIEW SHOWING RELATION OF BRIDGE TO THE TOPOGRAPHY OF THE APPROACH ROAD. - Speicher Bridge, Church Road over Tulpehocken Creek between Penn & North Heidelberg Townships, Bernville, Berks County, PA

125

Role of Topography in Geodetic Gravity Field Modelling.  

National Technical Information Service (NTIS)

Masses associated with the topography, bathymetry, and its isostatic compensation are a dominant source of gravity field variations, especially at shorter wavelengths. On global scales the topographic/isostatic effects are also significant, except for the...

R. Forsberg M. G. Sideris

1989-01-01

126

Linear and Nonlinear Stratified Spindown over Sloping Topography.  

National Technical Information Service (NTIS)

Ocean bottom boundary layers are regions adjacent to topography where turbulence mixes heat, momentum and biogeochemical tracers. These regions serve as a dynamical control on the circulation by dissipating energy and shape the local characteristics of th...

J. A. Benthuysen

2010-01-01

127

Geoid height versus topography for oceanic plateaus and swells  

NASA Astrophysics Data System (ADS)

Gridded geoid height data (Marsh et al.l, 1986) and gridded bathymetry data (Van Wykhouse, 1973) are used to estimate the average compensation depths of 53 oceanic swells and plateaus. The relationship between geoid height and topography is examined using Airy and thermal compensation models. It is shown that geoid height is linearly related to topography between wavelengths of 400 and 4000 m as predicted by isostatic compensation models. The geoid/topography ratio is dependent on the average depth of compensation. The intermediate geoid/topography ratios of most thermal swells are interpreted as a linear combination of the decaying thermal swell signature and that of the persisting Airy-compensated volcanic edifice.

Sandwell, David T.; MacKenzie, Kevin R.

1989-06-01

128

Stimulus control topography coherence theory: Foundations and extensions  

PubMed Central

Stimulus control topography refers to qualitative differences among members of a functional stimulus class. Stimulus control topography coherence refers to the degree of concordance between the stimulus properties specified as relevant by the individual arranging a reinforcement contingency (behavior analyst, experimenter, teacher, etc.) and the stimulus properties that come to control the behavior of the organism (experimental subject, student, etc.) that experiences those contingencies. This paper summarizes the rationale for analyses of discrimination learning outcomes in terms of stimulus control topography coherence and briefly reviews some of the foundational studies that led to this perspective. We also suggest directions for future research, including pursuit of conceptual and methodological challenges to a complete stimulus control topography coherence analysis of processes involved in discriminated and generalized operants. ImagesFigure 3Figure 5

McIlvane, William J.; Dube, William V.

2003-01-01

129

Cokriging surface elevation and seismic refraction data for bedrock topography.  

National Technical Information Service (NTIS)

Analysis of seismic refraction data collected at a proposed site of the Advanced Neutron Source (ANS) Facility showed a strong correlation between surface and bedrock topography. By combining seismically determined bedrock elevation data with surface elev...

J. E. Nyquist W. E. Doll R. K. Davis R. A. Hopkins

1992-01-01

130

Gravity driven shallow water models for arbitrary topography  

Microsoft Academic Search

We derive new models for gravity driven shallow water flows\\u000ain several space dimensions over a general topography.\\u000aA first model is valid for small slope variation, i.e. small curvature,\\u000aand a second model is valid for arbitrary topography.\\u000aIn both cases no particular assumption is made on the velocity profile in the material layer.\\u000aThe models are written for

Francois Bouchut; Michael Westdickenberg

2004-01-01

131

Phase contrast in Simultaneous Topography and Recognition imaging.  

PubMed

The operation of a force microscope in Simultaneous Topography and Recognition (TREC) imaging mode is analyzed by means of numerical simulations. Both topography and recognition signals are analyzed by using a worm-like chain force as the specific interaction between the functionalized tip probe and the sample. The special feedback mechanism in this mode is shown to couple the phase signal to the presence of molecular recognition interactions even in absence of dissipation. PMID:19523768

Fuss, M C; Sahagún, E; Köber, M; Briones, F; Luna, M; Sáenz, J J

2009-05-21

132

Defect analysis in crystals using X-ray topography  

Microsoft Academic Search

A brief review of X-ray topography—a nondestructive method for direct observation and characterization of defects in single crystals—is presented here. The origin and development of this characterization method and the different techniques derived from it are described. Emphasis is placed on synchrotron X-ray topography and its application in studying various crystal imperfec- tions. Mechanisms of contrast formation on X-ray topographs

Balaji Raghothamachar; Govindhan Dhanaraj; Jie Bai; Michael Dudley

2006-01-01

133

Surface topography evolvement of galvanized steels in sheet metal forming  

Microsoft Academic Search

U-channel forming tests were performed to investigate the surface topography evolvement of hot-dip galvanized(GI) and galvannealed(GA) steels and the effects of die hardness on sheet metal forming(SMF). Experimental results indicate that the surface roughness values of the two galvanized steels increase with the number of forming, i.e., the surface topographies of galvanized steels are roughened in SMF. Moreover, GI steel

Ying-ke HOU; Zhong-qi YU; Wei-gang ZHANG; Hao-min JIANG; Zhong-qin LIN

2009-01-01

134

Look-ahead Control of Heavy Trucks utilizing Road Topography  

Microsoft Academic Search

Abstract The power,to mass,ratio of a heavy,truck causes even moderate,slopes to have a significant influence on the motion. The velocity will inevitable vary within an interval that is primarily determined,by the ratio and the road topography. If further variations are actuated by a controller, there is a potential to lower the fuel consumption,by taking the upcoming,topography,into account. This possibility is

Erik Hellström

2007-01-01

135

The strength of contributions from topography mismatch and measurement filtering to simulated net ecosystem exchange in complex terrain  

NASA Astrophysics Data System (ADS)

Global scale carbon cycle inverse models provide invaluable information for the construction of empirically based carbon budgets based on in situ measurements. In landscapes of predominantly smooth topography inverse carbon cycle models are useful for diagnosing the magnitude and climate sensitivity of different regional carbon sinks. However, in landscapes of predominately complex topography inversion model results come with strong caveats for two reasons: 1) Coarse gridding of model topography can lead the model to sample observations at elevations far above the model surface, and 2) Transport wind fields over smoothed model representations of mountain regions are not always sufficiently resolved to inform the model about the source region for assimilated measurements. The uncertainty contributed by incorrect winds and topography mismatches (e.g., differences between the actual measurement elevation and model surface on the order of 1,000 m) is thought to be smaller for higher resolution regional inversion models (e.g., Gockede et al., 2010; Schuh et al. 2010), but these uncertainties are not well constrained for larger scale inversion systems (e.g., Peters et al., 2010), which are one of few ways for determining the relative priority of regional sinks. In this work we examine the effects on net ecosystem exchange (NEE) for a global scale inversion system when 1) topography mismatches are ameliorated, and 2) subset observations consistent with model resolution are used rather than observation-based subsets. Our focus is to use an example inversion model system, CarbonTracker (Peters et al., 2007; 2010), driven by CO2 mixing ratio measurements, including the RACCOON Network in the United States Mountain West (raccoon.ucar.edu), to quantify and compare the contribution to NEE from tower elevation mismatches and filtering strategies across biomes and and in terms of forecast skill (model data mismatch). We further compare our results to the differences in NEE over the same region from both inverse and forward models that participated in the North American Carbon Program Regional-Continental Model Synthesis.

Brooks, B.; Desai, A. R.; Stephens, B. B.; Jacobson, A. R.

2011-12-01

136

New method of topography simulation in photolithography  

NASA Astrophysics Data System (ADS)

Recently, photolithography simulation above topographical substrates has become a more and more interesting topic in submicrotechnology. Besides originating standing waves in the resist during exposure, substrate slopes cause specular reflections. Moreover, one can state diffraction effects if geometrical dimensions are in the same order of magnitude like exposure wavelength. The worst case that might occur is the so-called concave mirror effect. Different methods for field calculation are known from optical theory. Closed analytical treatments can be done merely for simple geometries. Direct solutions of Maxwells equations or Helmholtz equation as a boundary value problem by means of numerical methods (FDM or FEM/BEM) are difficult and computation is time consuming. Highly sophisticated computers (especially massively parallel machines) are required to realize acceptable operation times. We propose an alternative method, which is mainly based upon using the basic principles of Keller's Geometrical Theory of Diffraction (GTD) and their uniform extension (UTD), namely the locality principle, the boundary diffraction wave representation, and Keller's ray conception which includes diffracted rays. The first step now consists in the separation of a given diffracting surface in such a way that analytical solutions for the separated regions are known (canonical problem). Particularly in the two-dimensional (2-D) case, a topography can be approached by putting inclined (plane) faces together. This leads to the canonical problem of wedge diffraction, the exact solution of which was given at first by Sommerfeld. An asymptotic evaluation of his diffraction integral yields a partition of the total field in the geometrical-optical field and a diffracted field. In the 2-D case the latter is represented by a direction and polarization-dependent cylindrical wave, the inclination factor of which is denoted as diffraction coefficient in GTD. This GTD-coefficient fails both in the vicinity of and directly on the geometrical-optical boundaries and the edge of the wedge. (We have to distinguish between the two shadow- and the two reflexion-boundaries.) In such transition regions UTD-coefficients guarantee sufficient accuracy of field calculation, as can be shown by a comparison with exact solution (convergent expansion of the diffraction integral). These extended UTD-coefficients consist of four terms, each of them is related to one shadow- or reflexion-boundary. Remaining problems (especially in the 3-D case) like curved wedges and corner- or vertex-diffraction are discussed briefly. Wedges with impedance faces (e.g., reflectivity < 1) are involved by the application of a heuristical method from microwave theory. Furthermore, geometrical-optical field calculation within the bounds of GTD is described in brief. Based on our model explained above, a complete two-dimensional topography simulator was created. Running on a simple IBM-AT-386 the algorithm employs as much as or less time than the procedures basing on direct numerical solutions and requiring highly sophisticated machines. Resist bleaching is taken into consideration by several bleaching steps, according to Dill's differential equation in their difference approach. Numerical results for typical simulation situations (notching, grain, trapezium, concave mirror) are presented and compared with the literature. Additionally, special polarization effects could be predetermined by means of simulation and proved experimentally. Under certain conditions an essential improvement would be achieved by the application of polarized light.

Bischoff, Joerg; Glaubitz, Ulrich; Haase, Norbert

1992-06-01

137

Optimal spectral topography and its effect on model climate  

SciTech Connect

Gibbs oscillations in the truncated spectral representation of the earth`s topography are strongly reduced by determining its spectral coefficients as a minimum of a nonuniformly weighted, nonquadratic cost function. The cost function penalizes the difference between spectral and true topography with weights that are explicit functions of the topographic height and its gradient. The sensitivity of the Canadian Climate Centre general circulation model`s climate to the presence of Gibbs oscillations is determined for T32 and T48 resolutions by comparing the climates with optimal spectral topography to those with standard spectral topography. The main effect of Gibbs oscillations in the standard spectral topography is to induce spurious grid-scale ripples in the surface fluxes, which, for the surface energy balance, can be on the order of several tens of watts per square meter. Ripples in the surface energy balance, can be on the order of several tens of watts per square meter. Ripples in the surface fluxes are nearly absent in the model climate with the optimal spectral topography. 13 refs., 11 figs., 2 tabs.

Holzer, M. [Univ. of Victoria, British Columbia (Canada)

1996-10-01

138

Isidis Basin, Mars: Geology and Topography  

NASA Astrophysics Data System (ADS)

Building on Bridges et al. [2003, JGR 108], we are currently studying the general geologic history and evolution of the Isidis basin based on topographic and imaging data obtained by orbiting spacecraft such as Mars Global Surveyor (MGS) and Mars Odyssey. This study complements our recently completed analyses on Syrtis Major to the west [Hiesinger and Head, 2002, LPSC 1063] and the transition between Syrtis Major and Isidis [Ivanov and Head, 2002, LPSC 1341]. We are interested in a number of scientific questions, for example, what are the characteristics of the Isidis rim and what caused its present morphology? What is the role and fate of volatiles in the Isidis basin and what are the characteristics of the uppermost surface layer? Does the floor of the Isidis basin primarily consist of volcanic plains as indicated by wrinkle ridges and cone-like features, material deposited by a catastrophic collapse of the rim as proposed by Tanaka et al. [2000, GRL 29], or of sediments deposited in an ocean as suggested by Parker et al. [1989, Icarus 82]? What is the stratigraphy of the deposits within the Isidis basin and what processes were responsible for its present appearance? For our study we used MOLA topography data with a spatial resolution of 128 pixel/deg. The data allowed us to obtain a detailed view of the Isidis basin, its structure, stratigraphy, geologic history and its evolution. Our preliminary investigation let us conclude that (1) the basin floor is tilted towards the southwest with about 0.015 degree, (2) there are 2 types of ridges within the Isidis basin, (3) ridges of the thumbprint terrain are ~10-50 m high, less than ~5-7 km wide, and occur at narrowly constrained elevations of ~-3600 to -3700 m, (4) these ridges occur only within the innermost ring structure and most of them are not exposed at the lowest elevations, (5) wrinkle ridges are ~75-100 m high, less than ~70 km wide, hundreds of kilometers long and occur over a wide range of elevations, (6) the rim of Isidis exhibits a wide range of elevations of ~7500-8000 m. The floor of the Isidis basin has been chosen by the European Space Agency (ESA) as the landing site for the first European lander on Mars, named Beagle, and is under consideration as a potential landing site for one of the NASA MER rovers. While Beagle will investigate the characteristics of the uppermost surface layers, the Mars Express spacecraft will orbit the planet to acquire global high-resolution remote sensing data and to ensure data downlink from the lander to Earth.

Hiesinger, H.; Head, J. W., III

2003-04-01

139

Predicting surface dynamic topographies of stagnant lid planetary bodies  

NASA Astrophysics Data System (ADS)

Although planetary mantles are viscoelastic media, numerical models of thermal convection in a viscoelastic spherical shell are still very challenging. Here, we examine the validity of simplified mechanical and rheological frameworks classically used to approximate viscoelastic dynamic topography. We compare three simplified approaches to a linear Maxwell viscoelastic shell with a pseudo upper free-surface, considered as the reference model. A viscous model with a free-slip boundary condition at the surface correctly reproduces the final relaxed shape of the viscoelastic body but it cannot reproduce the time evolution of the viscoelastic topography. Nevertheless, characterizing the topography development is important since it can represent a significant fraction of the history for planets having a thick and rigid lithosphere (e.g. Mars). A viscous model with a pseudo free-surface, despite its time-dependency, also systematically fails to describe correctly these transient stages. An elastic filtering of the instantaneous viscous topography is required to capture the essence of the time evolution of the topography. We show that a single effective elastic thickness is needed to correctly reproduce the constant transient viscoelastic topography obtained when the lithosphere corresponds to a step-like viscosity variation, while a time-dependence of the effective elastic thickness must be considered to take account of realistic temperature-dependent viscosity variations in the lithosphere. In this case, the appropriate thickness of the elastic shell can be evaluated, at a given instant, with a simple procedure based on the local Maxwell time. Furthermore, if the elastic filtering is performed using the thin elastic shell formulation, an unrealistic degree-dependence of the thickness of the elastic shell is needed to correctly approximate the viscoelastic topography. We show that a model that fully couples a viscous body to an elastic shell of finite thickness estimated using the local Maxwell time gives the best approximation of the viscoelastic deformation, whatever the degree of the load and the time of loading.

Dumoulin, C.; ?adek, O.; Choblet, G.

2013-10-01

140

Effects of latent heat release at phase boundaries on flow in the Earth’s mantle, phase boundary topography and dynamic topography at the Earth’s surface  

Microsoft Academic Search

Mantle flow models that do not consider the effects of latent heat on phase boundaries typically predict dynamic surface topography too large to be compatible with observations. Here these effects were implemented in a mantle flow model and resulting changes in dynamic topography and topography of phase boundaries were computed. Inclusion of these effects was found to reduce the rms

Bernhard Steinberger

2007-01-01

141

Corneal topography from spectral optical coherence tomography (sOCT)  

PubMed Central

We present a method to obtain accurate corneal topography from a spectral optical coherence tomography (sOCT) system. The method includes calibration of the device, compensation of the fan (or field) distortion introduced by the scanning architecture, and image processing analysis for volumetric data extraction, segmentation and fitting. We present examples of three-dimensional (3-D) surface topography measurements on spherical and aspheric lenses, as well as on 10 human corneas in vivo. Results of sOCT surface topography (with and without fan-distortion correction) were compared with non-contact profilometry (taken as reference) on a spherical lens, and with non-contact profilometry and state-of-the art commercial corneal topography instruments on aspheric lenses and on subjects. Corneal elevation maps from all instruments were fitted by quadric surfaces (as well as by tenth-order Zernike polynomials) using custom routines. We found that the discrepancy in the estimated radius of curvature from nominal values in artificial corneas decreased from 4.6% (without fan distortion correction) to 1.6% (after fan distortion correction), and the difference in the asphericity decreased from 130% to 5%. In human corneas, the estimated corneal radius of curvature was not statistically significantly different across instruments. However, a Bland-Altman analysis showed consistent differences in the estimated asphericity and corneal shape between sOCT topographies without fan distortion correction and the rest of the measurements.

Ortiz, Sergio; Siedlecki, Damian; Perez-Merino, Pablo; Chia, Noelia; de Castro, Alberto; Szkulmowski, Maciej; Wojtkowski, Maciej; Marcos, Susana

2011-01-01

142

Micro-topography of dental enamel and root cementum.  

PubMed

The focus for the present study was to characterise dental enamel and cementum at the cervical region of healthy teeth by use of interferometry. The effect of a protein-dissolving enzyme, used for cleaning (Neutrase) on the surface topography, was also evaluated. Knowledge about the normal variation of surface topography of natural teeth is limited. In the design of artificial surfaces, intended to replace the function of lost biological surfaces, detailed knowledge of the latter is therefore of great importance. Nine health caries free premolars were used. The root cementum of three teeth was used for evaluation of Neutrase on the surface. On the six remaining teeth, the differences between the surface textures of enamel and root cementum were evaluated using 3D Interferometry. No statistical significant effect of Neutrase was identified. A significant difference between enamel and root cementum concerning surface topography using the different 3D parameters was recorded. When comparing values from the literature, the topography of artificial materials used in dentistry show similarities with the topography of the enamel and root cementum surfaces evaluated. PMID:19522316

Edblad, Thorsten; Hoffman, Maria; Hakeberg, Magnus; Ortengren, Ulf; Milledning, Percy; Wennerberg, Ann

2009-01-01

143

Smoking topography and abstinence in adult female smokers.  

PubMed

Preliminary evidence, within both adults and adolescents, suggests that the intensity with which cigarettes are smoked (i.e., smoking topography) is predictive of success during a cessation attempt. These reports have also shown topography to be superior compared to other variables, such as cigarettes per day, in the prediction of abstinence. The possibility that gender may influence this predictive relationship has not been evaluated but may be clinically useful in tailoring gender-specific interventions. Within the context of a clinical trial for smoking cessation among women, adult daily smokers completed a laboratory session that included a 1-hour ad libitum smoking period in which measures of topography were collected (N=135). Participants were then randomized to active medication (nicotine patch vs. varenicline) and abstinence was monitored for 4weeks. Among all smoking topography measures and all abstinence outcomes, a moderate association was found between longer puff duration and greater puff volume and continued smoking during the active 4-week treatment phase, but only within the nicotine patch group. Based on the weak topography-abstinence relationship among female smokers found in the current study, future studies should focus on explicit gender comparisons to examine if these associations are specific to or more robust in male smokers. PMID:24018226

McClure, Erin A; Saladin, Michael E; Baker, Nathaniel L; Carpenter, Matthew J; Gray, Kevin M

2013-08-17

144

Topography and functional information of plasma membrane.  

PubMed

By using atomic force microscope (AFM), the topography and function of the plasmalemma surface of the isolated protoplasts from winter wheat mesophyll cells were observed, and compared with dead protoplasts induced by dehydrating stress. The observational results revealed that the plasma membrane of living protoplasts was in a state of polarization. Lipid layers of different cells and membrane areas exhibited distinct active states. The surfaces of plasma membranes were unequal, and were characterized of regionalisation. In addition, lattice structures were visualized in some regions of the membrane surface. These typical structures were assumed to be lipid molecular complexes, which were measured to be 15.8+/-0.09 nm in diameter and 1.9+/-0.3 nm in height. Both two-dimensional and three-dimensional imaging showed that the plasmalemma surfaces of winter wheat protoplasts were covered with numerous protruding particles. In order to determine the chemical nature of the protruding particles, living protoplasts were treated by proteolytic enzyme. Under the effect of enzyme, large particles became relatively looser, resulting that their width was increased and their height decreased. The results demonstrated that these particles were likely to be of protein nature. These protein particles at plasmalemma surface were different in size and unequal in distribution. The diameter of large protein particles ranged from 200 to 440 nm, with a central micropore, and the apparent height of them was found to vary from 12 to 40 nm. The diameter of mid-sized protein particles was between 40-60 nm, and a range of 1.8-5 nm was given for the apparent height of them. As for small protein particles, obtained values were 12-40 nm for their diameter and 0.7-2.2 nm for height. Some invaginated pits were also observed at the plasma membrane. They were formed by the endocytosis of protoplast. Distribution density of them at plasmalemma was about 16 pits per 15 microm(2). According to their size, we classified the invaginated pits into two types--larger pits measuring 139 nm in diameter and 7.2 nm in depth, and smaller pits measuring 96 nm in diameter and 2.3 nm in depth. On dehydration-induced dead protoplasts, the degree of polarization of plasma membranes decreased. Lipid molecular layers appeared relatively smooth, and the quantity of integral proteins reduced a lot. Invaginated pits were still detectable at the membrane surface, but due to dehydration-induced protoplast contraction, the orifice diameter of pits reduced, and their depth increased. Larger pits averagely measuring 47.4 nm in diameter and 31.9 nm in depth, and smaller pits measuring 26.5 nm in diameter and 43 nm in depth at average. The measured thickness of plasma membranes of mesophyll cells from winter wheat examined by AFM was 6.6-9.8 nm, thicker in regions covered with proteins. PMID:18239886

Sun, DeLan; Chen, JianMin; Song, YanMei; Zhu, ChuanFeng; Pan, GeBo; Wan, LiJun

2008-02-01

145

Surface topography prediction on laser processed tool steel  

NASA Astrophysics Data System (ADS)

In laser surface treatment the laser beam is used as energy source for surface modification improving aspects such as mechanical properties, tribology or surface texture. Modeling tools have special interest in processes with many variables, like laser surface processing, in order to minimize the tryout testing to find the optimal process parameters. The work presented here focuses on the prediction of the final topography in laser polishing process. By FFT analysis of the surface profile it is possible to get the different frequency components of the initial topography. On the other hand, thermal field simulation was carried out to evaluate the melt duration. Matching this with the spatial frequency damping during process, the reconstruction of the processed topography was obtained.

Ukar, E.; Lamikiz, A.; Martínez, S.; López de Lacalle, L. N.

2012-04-01

146

Topographies of plasma-hardened surfaces of poly(dimethylsiloxane)  

SciTech Connect

We studied the formation of surface layers hardened by plasma-enhanced oxidation of the silicone elastomer poly(dimethylsiloxane). We explored the largest parameter space surveyed to date. The surface layers may wrinkle, crack, or both, under conditions that at times are controlled by design, but more often have been discovered by trial-and-error. We find four distinct topographies: flat/wrinkled/cracked/cracked and wrinkled. Each topography is clearly separated in the space of plasma dose versus plasma pressure. We analyzed wrinkle amplitude and wavelength by atomic force microscopy in the tapping mode. From these dimensions we calculated the elastic modulus and thickness of the hard surface layer, and inferred a graded hardness, by employing a modified theoretical model. Our main result is the identification of the parameters under which the technologically important pure wrinkled, crack-free topography is obtained.

Goerrn, Patrick; Wagner, Sigurd [Department of Electrical Engineering and Princeton Institute for the Science and Technology of Materials, Princeton University, Princeton, New Jersey 08544 (United States)

2010-11-15

147

Imaging defects in macromolecular crystals with x-ray topography  

NASA Astrophysics Data System (ADS)

X-ray topography is a well established technique to characterize growth or process induced defects. As a characterization tool for crystal growers X-ray topography is probably the simplest non destructive imaging technique available. However, only recently it has been applied to image growth induced defects in protein crystals.We will discuss the use of white and monochromatic x-ray topography methods in understanding macromolecular growth techniques and diffraction properties. White and monochromatic synchrotron radiation from beamline X26C at the National Synchrotron Light Source (NSLS) at the Brookhaven National Laboratory (BNL) were employed in x-ray topographic studies of different macromolecular systems grown by different techniques. Results show that growth conditions and handling affected the quality of the crystals. A high correlation between crystal quality and diffraction characteristics was observed. Above all x-ray topographic methods proved to be non destructive, at least for the proteins studied, lysozyme, concanavalin and myoglobin.

Stojanoff, V.; Siddons, D. P.

1996-03-01

148

Surface topographies for non-toxic bioadhesion control  

US Patent & Trademark Office Database

An article has a surface topography for resisting bioadhesion of organisms and includes a base article having a surface. A composition of the surface includes a polymer. The surface has a topography comprising a pattern defined by a plurality of spaced apart features attached to or projected into the base article. The plurality of features each have at least one microscale dimension and at least one neighboring feature having a substantially different geometry. An average feature spacing between adjacent ones of the features is between 10 .mu.m and 100 .mu.m in at least a portion of the surface. The surface topography can be numerically represented using at least one sinusoidal function. In one embodiment, the surface can comprise a coating layer disposed on the base article.

2010-01-26

149

Influence of nanophase titania topography on bacterial attachment and metabolism  

PubMed Central

Surfaces with nanophase compared to conventional (or nanometer smooth) topographies are known to have different properties of area, charge, and reactivity. Previously published research indicates that the attachment of certain bacteria (such as Pseudomonas fluorescens 5RL) is higher on surfaces with nanophase compared to conventional topographies, however, their effect on bacterial metabolism is unclear. Results presented here show that the adhesion of Pseudomonas fluorescens 5RL and Pseudomonas putida TVA8 was higher on nanophase than conventional titania. Importantly, in terms of metabolism, bacteria attached to the nanophase surfaces had higher bioluminescence rates than on the conventional surfaces under all nutrient conditions. Thus, the results from this study show greater select bacterial metabolism on nanometer than conventional topographies, critical results with strong consequences for the design of improved biosensors for bacteria detection.

Park, Margaret R; Banks, Michelle K; Applegate, Bruce; Webster, Thomas J

2008-01-01

150

Topographies of plasma-hardened surfaces of poly(dimethylsiloxane)  

NASA Astrophysics Data System (ADS)

We studied the formation of surface layers hardened by plasma-enhanced oxidation of the silicone elastomer poly(dimethylsiloxane). We explored the largest parameter space surveyed to date. The surface layers may wrinkle, crack, or both, under conditions that at times are controlled by design, but more often have been discovered by trial-and-error. We find four distinct topographies: flat/wrinkled/cracked/cracked and wrinkled. Each topography is clearly separated in the space of plasma dose versus plasma pressure. We analyzed wrinkle amplitude and wavelength by atomic force microscopy in the tapping mode. From these dimensions we calculated the elastic modulus and thickness of the hard surface layer, and inferred a graded hardness, by employing a modified theoretical model. Our main result is the identification of the parameters under which the technologically important pure wrinkled, crack-free topography is obtained.

Görrn, Patrick; Wagner, Sigurd

2010-11-01

151

Laser-based nanoengineering of surface topographies for biomedical applications  

NASA Astrophysics Data System (ADS)

In this study femtosecond laser systems were used for nanoengineering of special surface topographies in silicon and titanium. Besides the control of feature sizes, we demonstrated that laser structuring caused changes in material wettability due to a reduced surface contact area. These laser-engineered topographies were tested for their capability to control cellular behavior of human fibroblasts, SH-SY5Y neuroblastoma cells, and MG-63 osteoblasts. We found that fibroblasts reduced cell growth on the structures, while the other cell types proliferated at the same rate. These findings make laser-surface structuring very attractive for biomedical applications. Finally, to explain the results the correlation between topography and the biophysics of cellular adhesion, which is the key step of selective cell control, is discussed.

Schlie, Sabrina; Fadeeva, Elena; Koroleva, Anastasia; Ovsianikov, Aleksandr; Koch, Jürgen; Ngezahayo, Anaclet; Chichkov, Boris. N.

2011-04-01

152

Introduction to Special Section on Tectonics and Topography  

NASA Astrophysics Data System (ADS)

This special section on tectonics and topography developed from an American Geophysical Union Chapman Conference convened in the late summer of 1992 in Snowbird, Utah. The intent of the gathering was to assemble a diverse group of Earth scientists working on ultimately the same problem: the interaction between crustal and surficial processes or, euphemistically, tectonics and topography. Through numerous and enthusiastic conversations, it became clear to us prior to the Chapman Conference that many people were working on the interaction between tectonics and topography but about half of these were either unaware of the others or were aghast at the way in which the others simplified their subject (and vice versa for the other half!). To our delight, the conference brought forth a wonderful array of scientists from virtually all subdisciplines of geology, and the desire for mutual help and a sympathetic ear was palpable.

Merritts, Dorothy; Ellis, Michael

1994-06-01

153

Ulva linza zoospore sensitivity to systematic variation of surface topography  

NASA Astrophysics Data System (ADS)

The use of surface topographical microstructure is abundant in nature. The lotus plant uses a fractal-like topography to create a highly non-wetting surface that self-cleans as water drops take dirt particles with them as they roll off. Analysis of how topography affects surface interactions offers a unique opportunity to attack a problem that affects our economy and societal health significantly. The attachment of biological material to manmade surfaces can be looked at as fouling or directed adhesion. Marine fouling on ship hulls costs the United States $600 million each year due to increased fuel usage caused by drag. Hospital-acquired methicillin-resistant Staphylococcus aureus infections cause thousands of deaths annually as a result of colonization of hospital surfaces. The lack of biocompatible synthetic surfaces for implants such as vascular grafts lead to restenosis as cells are unable to develop a natural interaction with the graft surface. In each circumstance there is much to learn about the complicated attachment process. This work expands the investigation of the role of topography in the attachment of the green fouling algae Ulva linza to poly(dimethylsiloxane) surfaces. Spore attachment density was correlated to the Wenzel roughness ratio on low surface energy, high-modulus poly(dimethylsiloxane)-grafted-silicon topographies. The role of topography on a scale less than the size of a spore was investigated on nano-roughened poly(dimethylsiloxane) elastomer surfaces. For a specific group of patterns, the spatial distribution of spores attached to topographies was quantitatively analyzed and shown to correlate with feature dimensions.

Sheats, Julian Taylor

154

Numerical investigation of MASW applications in presence of surface topography  

NASA Astrophysics Data System (ADS)

In the applications of multichannel analysis of surface waves (MASW), dispersion curves are usually picked in an energy tracing manner on dispersion images. They are compared with the theoretical dispersion curves based on a horizontally layered earth model during the subsequent inversion for shear-wave velocities. Surface topography can strongly influence energy distribution on a dispersion image. In theory, static correction should be applied to seismic records before generating dispersion images if there are any elevation variations along a two-dimensional (2D) survey line. The out-of-plane noise from side areas of a survey line in three dimensions (3D) can also contaminate the recorded wavefield. We synthesize the seismograms through finite-difference modeling for 12 types of 2D earth models that represent the basic elements of topography along a survey line. The dispersion images are compared with the corresponding theoretical dispersion curves that are calculated by ignoring the topography of the models. The comparison shows that errors of the picked Rayleigh-wave phase velocities can be constrained within 4% if a slope angle of the topography is less than about 10°. For steeper topography, errors of the picked phase velocities are greater than 4% and static correction are recommended before the dispersion analysis. In the 3D case, we investigate a set of 3D levee-shaped earth models to evaluate the errors caused by the out-of-plane noise from the edge of an embankment. The analysis suggests that the distance between the edge of an embankment and a MASW survey line should be at least 1/10 of the dominant Rayleigh-wave wavelength so that energy distortion on dispersion images due to topography are less significant than that caused by other noises.

Zeng, Chong; Xia, Jianghai; Miller, Richard D.; Tsoflias, Georgios P.; Wang, Zhejiang

2012-09-01

155

Data combination in topography measurement of revolving objects  

NASA Astrophysics Data System (ADS)

Several photos of projected gratings patterns should be taken from different angles, when 3D topography of revolving objects is measured by grating projected method. How to combine the measured data of grating projected patterns is a key factor of measuring 3D topography of revolving objects. A new data combination method, which is based on cylinder coordinate transform, is proposed in this paper. The equations and operating steps are introduced and the experiments are given in this paper. All the projected gratings patterns are processed by FFT phase technique.

Han, Yun; Ma, Li; He, Shiping; Liu, Lang

2003-04-01

156

Adaptation of an Asperity Ploughing Model to Measured Roll Topographies  

NASA Astrophysics Data System (ADS)

A previously published asperity ploughing model has been adapted in order to approximate the measured as-ground roll surface topography. The model is then integrated with classical cold rolling plastic deformation equations including coupling to the lubricant film evolution through the roll bite. The friction distribution through the roll bite is thus a function of the specific details of the roll surface topography as well as the process parameters. predictions of roll force, torque and forward slip as well as sliding distance and volume of metal swept out by the asperities are then made and compared to experimental measurements for an aluminum alloy rolled on a laboratory rolling mill.

Lalli, L. A.; Malkani, H. G.; Sheu, S.

2004-06-01

157

Wide angle X-ray diffraction topography of polycrystalline materials  

SciTech Connect

X-ray topography is characterized by the spatially resolved detection of scattering of a material. The advantages of radiographic imaging can be combined with the analytical information revealed by Wide Angle X-Ray Diffraction. Beyond the limitations of the well-known Single Crystal Topography new approaches by single beam scanning techniques under pre-selected scattering conditions permit the topographic characterization of polycrystalline or amorphous solids or liquids. The principles of different topographic methods and their application to polymer and ceramic composites are presented.

Hentschel, Manfred P.; Lange, Axel; Schors, Joerg; Wald, Oliver; Harbich, Karl-Wolfram [Federal Institute for Materials Research and Testing, BAM-VIII.32, D-12200 Berlin (Germany)

1999-12-02

158

Geoid, topography, and convection-driven crustal deformation on Venus  

NASA Astrophysics Data System (ADS)

High-resolution Magellan images and altimetry of Venus reveal a wide range of styles and scales of surface deformation that cannot readily be explained within the classical terrestrial plate tectonic paradigm. The high correlation of long-wavelength topography and gravity and the large apparent depths of compensation suggest that Venus lacks an upper-mantle low-viscosity zone. A key difference between Earth and Venus may be the degree of coupling between the convecting mantle and the overlying lithosphere. Mantle flow should then have recognizable signatures in the relationships between surface topography, crustal deformation, and the observed gravity field.

Simons, Mark; Hager, Bradford H.; Solomon, Sean C.

1992-12-01

159

The Impact of Weather & Topography on Landslide Development  

NSDL National Science Digital Library

The Real World Learning Objects Resource Library has provided this activity to demonstrate the role of weather and topography in environmental disasters. Students will use real GIS data to analyze the relationship between weather, topography and landslides. Background materials and worksheets are provided in the âÂÂContent Materialsâ section, and the procedure for students to follow is clearly outlined. Additional materials that students may find helpful are located in the âÂÂSupplementary Resourcesâ section. This is an excellent resource for environmental science and earth science teachers that can be used in the classroom or as a homework assignment.

Kimbler, Frank

2008-02-01

160

Mercury's Thermal Evolution, Dynamical Topography and Geoid  

NASA Astrophysics Data System (ADS)

Among the terrestrial planets Mercury is not only the smallest, but also the densest (after correction for self-compression). To explain Mercury's high density it is considered likely that the planet's mantle was removed during a giant impact event, when proto-Mercury was already differentiated into an iron core and a silicate mantle. Beside the damage to the planet's mantle the vaporization would cause a significant loss of volatile elements, leaving the remaining planet molten and dominated by extremely refractory material.Since the arrival of a spacecraft at the enigmatic planet is not to be expected before 2011 (Messenger) or 2019 (BepiColombo) we might already prepare ourselves for the upcoming results and perform tests that allow some anticipation of the measured data. The hermean mantle is modelled as an internally and bottom heated, isochemical fluid in a spherical shell. The principle of this convection model is widely accepted and is used for various models of thermal evolution of terrestrial planets, e.g., the Earth, Mars or the Moon. We are solving the hydrodynamical equations, derived from the conservation of mass, momentum and energy. A program originally written by S. Zhang is used to solve the temperature field which employs a combination of a spectral and a finite difference method. Beside the large core as a heat source 'from below' the decay of radioactive isotopes provides internal heating of the hermean mantle. The viscosity of the mantel material depends exponentially on the inverse temperature. The model results show the typical behaviour of a one-plate-planet, meaning the surface is not broken into several tectonic plates but the outside is a single rigid shell. The thermal evolution is generally charaterized by the growth of a massive lithosphere on top of the convecting mantle. The lower mantle and core cool comparatively little and stay at temperatures between 1900K and 2000K until about 2.0Ga after the simulation was started. The stagnant lid comprises roughly half the mantle after only 0.5Ga. Since the rigid lithosphere does not take part in the convection anymore, the heat coming from the interior (due to the cooling of the large core) can only be transported through the lithosphere by thermal conduction. This is a significantly less effective mechanism of heat transport than convection and hence the lithosphere forms an insulating layer. As a result, the interior is kept relatively warm.Because the mantle is relatively shallow compared to the planet's radius, and additionally the thick stagnant lid is formed relatively rapid, the convection is confined to a layer of only about 200km to 300km. Convection structures are therefore relatively small structured. The flow patterns in the early evolution show that mantle convection is characterized by numerous upwelling plumes, which are fed by the heat flow from the cooling core. These upwellings are relatively stable regarding their spatial position. As the core cools down the temperature anomalies become colder and less pronounced but not less numerous. In our calculations, a region of partial melt in the mantle forms immediately after the start of the model at a depths of roughly 220km. While in the entire lower mantle the temperature exceeds the solidus, the highest melt degrees can be found in the upwelling plumes. The partial molten region persists a significant time (up to 2.5Ga). How long the partial molten zone actually survives depends strongly on the initial conditions of the model. For instance, an outer layer with a reduced thermal conductivity would keep the lower mantle significantly warmer and a molten layer survives longer. The hot upwellings cause a surface deformation (dynamical topography) which itself causes a gravity anomaly. Due to the weak constraints of important parameters (e.g. sulfur content of the core, mantle rheology, amount and distribution of radiogenic heat sources, planetary contraction, thermal conductivity, etc) numerous models are required to understand the importance and influence of the mentioned variables.

Ziethe, Ruth; Benkhoff, Johannes

161

A Spherical Harmonic Analysis of the Earth's Topography  

Microsoft Academic Search

This letter is a correction to the letter of the same title by Lee and Kaula [1967]. In 1971 two independent harmonic analyses of the topography at Meudon and Los Angeles found the results of Lee and Kaula [1967] to be incorrect. The error of the 1967 analysis has since been found to be an insufficient dimension (W. H. K.

Georges Balmino; Kurt Lambeck; William M. Kaula

1973-01-01

162

Characterization of the Spectral Density of Residual Ocean Floor Topography.  

National Technical Information Service (NTIS)

Ocean floor topography can be characterized as a signal related to lithospheric cooling and a residual; the residual can be further modeled by comparing the shape of its power spectrum with that of a fractal process. Power spectra of Seabeam profiles alon...

L. E. Gilbert A. Malinverno

1988-01-01

163

The role of topography in geodetic gravity field modelling  

Microsoft Academic Search

Masses associated with the topography, bathymetry, and its isostatic compensation are a dominant source of gravity field variations, especially at shorter wavelengths. On global scales the topographic\\/isostatic effects are also significant, except for the lowest harmonics. In practice, though, global effects need not be taken into account as such effects are included in the coefficients of the geopotential reference fields.

R. Forsberg; M. G. Sideris

1989-01-01

164

The changing topography of corroding mild steel surfaces in seawater  

Microsoft Academic Search

The corrosion of mild steel exposed to marine immersion conditions typically is not uniform although it is often idealized as such. Anodic regions and micro-pits develop very quickly after first exposure and eventually there is the development of shallow broad pits. This transition of the surface topography and the processes involved are still not completely understood. The present paper presents

Robert Jeffrey; Robert E. Melchers

2007-01-01

165

Some Bristol Prague explorations in x-ray topography  

Microsoft Academic Search

This paper briefly chronicles a long-standing and productive collaboration between the Institute of Physics, Czech Academy of Science and the H H Wills Physics Laboratory. It began in early 1962 with a brief visit to Bristol by Milena Polcarová. The initial aim, successfully achieved, was the mapping by transmission topography of dislocations in melt-grown single crystals of a Fe Si

A. R. Lang

2005-01-01

166

On the long-wavelength correlation between gravity and topography  

NASA Astrophysics Data System (ADS)

Spherical harmonic expansions of the topography, the topographic isostatic reduction potential and the gravity potential of the Earth now exist complete to degree (N) and order 180. A correlation analysis of the various fields by degree was made. While the general correlation between gravity and topography for the sets is around 50% for N 15, the correlation with GEM10C is considerably lower for N 36. This indicates that this set is unreliable above this degree. The topographic isostatic reduction potential may be computed either rigorously by integrating the topography and is compensation or by condensing the topography and its compensating masses. In the last case the spherical harmonic coefficients of the isostatic reduction potential are related in a simple linear manner to the spherical harmonic coefficients of the expansion of the topographic heights. An optimal depth of compensation for each degree was determined by requiring the reduced field to be as smooth as possible. Despite between 35 and 15 km were found for N 20, which are much lower than the values found earlier using another optimal depth principle.

Tscherning, C. C.

167

Geopotential Topography of Deep Levels in the Pacific Ocean.  

National Technical Information Service (NTIS)

After examination of the baroclinic structure below 3000 db, recent data were used to map the geopotential topography at 1000, 1500, and 2000 db (referred to 3000 db) in the Pacific Ocean. In the high-latitude regions and in the western boundary currents,...

R. K. Reed

1970-01-01

168

Topography and refractometry of nanostructures using spatial light interference microscopy  

Microsoft Academic Search

Spatial light interference microscopy (SLIM) is a novel method developed in our laboratory that provides quantitative phase images of transparent structures with a 0.3 nm spatial and 0.03 nm temporal accuracy owing to the white light illumination and its common path interferometric geometry. We exploit these fea- tures and demonstrate SLIM's ability to perform topography at a single atomic layer

Zhuo Wang; Ik Su Chun; Xiuling Li; Zhun-Yong Ong; Eric Pop; Larry Millet; Martha Gillette; Gabriel Popescu

2010-01-01

169

Heterogeneous energetic topographies generated by a diffusional mechanism  

Microsoft Academic Search

In the present paper, we study the main characteristic features of surface energetic topographies generated via the evolution of a single adsorbed particle whose mobility strongly affects the adsorption energy of each visited site. This tracer changes its coordinates by means of activated jumps to nearest-neighbor sites modifying the adsorption energy of each visited site according to a very simple

A. J. Ramirez-Pastor; F. Bulnes; F. Nieto

2001-01-01

170

Short wavelength topography on the inner-core boundary  

PubMed Central

Constraining the topography of the inner-core boundary is important for studies of core–mantle coupling and the generation of the geodynamo. We present evidence for significant temporal variability in the amplitude of the inner core reflected phase PKiKP for an exceptionally high-quality earthquake doublet, observed postcritically at the short-period Yellowknife seismic array (YK), which occurred in the South Sandwich Islands within a 10-year interval (1993/2003). This observation, complemented by data from several other doublets, indicates the presence of topography at the inner-core boundary, with a horizontal wavelength on the order of 10 km. Such topography could be sustained by small-scale convection at the top of the inner core and is compatible with a rate of super rotation of the inner core of ?0.1–0.15° per year. In the absence of inner-core rotation, decadal scale temporal changes in the inner-core boundary topography would provide an upper bound on the viscosity at the top of the inner core.

Cao, Aimin; Masson, Yder; Romanowicz, Barbara

2007-01-01

171

Plate detachment, asthenosphere upwelling, and topography across subduction zones  

Microsoft Academic Search

This study analyzes the topography across subduction zones, considering the separate contributions of the crust and the mantle lithosphere to the observed surface elevation. We have found a transition from a region where the overriding plate is coupled to the descending slab and pulled down along with it to a region where the overriding plate floats freely on the asthenosphere.

Zohar Gvirtzman; Amos Nur

1999-01-01

172

Deep topographies in the fiction of Uzma Aslam Khan  

Microsoft Academic Search

This article examines the novels Trespassing (2003) and The Geometry of God (2008) by Pakistani author Uzma Aslam Khan, and specifically her deployment of a complex symbolic apparatus constructed from prehistory, geography and history. Drawing on the fossil?rich soil of northern Pakistan and the Arabian Sea coastline in the south, Khan delineates a deep topography for Pakistan as a source

Ananya Jahanara Kabir

2011-01-01

173

Gravitational field and topography of Venus: static vs. dynamic models  

NASA Astrophysics Data System (ADS)

The gravitational field and topography of Venus are strongly correlated. In distinction to the Earth the correlation is significant not only at intermediate and short wavelengths but also at the long-wavelength part of the spectrum. Several studies have attempted to explain this fact by isostatic compensation of the surface topography (with a depth of compensation usually smaller than 50 km) while some others have argued for a dynamical origin of surface features. In the present study we examine the both concepts mentioned above using the most recent spherical harmonic models of topography (GTDR.3) and gravity (MGNP180U) of the planet. We show that these models are consistent with the concept of Airy isostasy at degrees greater than 40, with the apparent depth of compensation (ADC) around 35 km. At degrees 2-40 the ADC decreases more or less monotonously from 200 km to 40 km. This behavior cannot be explained by a simple model of Airy isostasy. The topography and gravity signals in this spectral interval can be, however, well predicted dynamically by a quasi steady-state model of thermal convection in the mantle of Venus. Assuming that the lateral distribution of the buoyancy force does not vary with depth (which roughly corresponds to a plume-like style of mantle convection) we obtain a very good agreement between the observed and predicted data. The best fit to the data is found for the profile in which the viscosity increases only weakly with depth.

Pauer, M.

2003-04-01

174

Short wavelength topography on the inner-core boundary.  

PubMed

Constraining the topography of the inner-core boundary is important for studies of core-mantle coupling and the generation of the geodynamo. We present evidence for significant temporal variability in the amplitude of the inner core reflected phase PKiKP for an exceptionally high-quality earthquake doublet, observed postcritically at the short-period Yellowknife seismic array (YK), which occurred in the South Sandwich Islands within a 10-year interval (1993/2003). This observation, complemented by data from several other doublets, indicates the presence of topography at the inner-core boundary, with a horizontal wavelength on the order of 10 km. Such topography could be sustained by small-scale convection at the top of the inner core and is compatible with a rate of super rotation of the inner core of approximately 0.1-0.15 degrees per year. In the absence of inner-core rotation, decadal scale temporal changes in the inner-core boundary topography would provide an upper bound on the viscosity at the top of the inner core. PMID:17190798

Cao, Aimin; Masson, Yder; Romanowicz, Barbara

2006-12-26

175

Short Wavelength Topography on the Inner Core Boundary  

NASA Astrophysics Data System (ADS)

Constraining the topography of the inner core boundary (ICB) is important for studies of core-mantle coupling and the generation of the geodynamo. We present evidence for significant temporal variability in the amplitude of the inner core reflected phase PKiKP for an exceptionally high quality earthquake doublet, which occurred in the South Sandwich Islands within a ten year interval (1993/2003). This doublet was observed post-critically at the short period Yellowknife seismic array (YK). The analysis of PKIKP/PKiKP amplitude ratios indicates that the PKiKP phases for the 1993 event - but not the 2003 event - are significantly defocused by structure near the inner core boundary (ICB). This observation cannot be explained by small differences in the eearthquake source, interference with another local, regional or teleseismic event, or different scattering from local heterogeneities near the stations or the sources. Combined with data from several other doublets, we infer the presence of topography at the inner- core boundary, with a horizontal wavelength of about 10 km. Such topography could be sustained by small scale convection at the top of the inner core, and is compatible with a rate of super-rotation of the inner core of ~0.1-0.15 deg/year. In the absence of inner core rotation, decadal scale temporal changes in the ICB topography would provide an upper bound on the viscosity at the top of the inner core.

Romanowicz, B.; Cao, A.; Masson, Y.

2006-12-01

176

Crustal structure of Mars from gravity and topography  

Microsoft Academic Search

Mars Orbiter Laser Altimeter (MOLA) topography and gravity models from 5 years of Mars Global Surveyor (MGS) spacecraft tracking provide a window into the structure of the Martian crust and upper mantle. We apply a finite-amplitude terrain correction assuming uniform crustal density and additional corrections for the anomalous densities of the polar caps, the major volcanos, and the hydrostatic flattening

G. A. Neumann; M. T. Zuber; M. A. Wieczorek; P. J. McGovern; F. G. Lemoine; D. E. Smith

2004-01-01

177

Tectonic shortening and topography in the central High Atlas (Morocco)  

NASA Astrophysics Data System (ADS)

Three cross sections of the Moroccan High Atlas illustrate the structural geometry and relationship between tectonic shortening and topography in this Cenozoic intracontinental mountain range. The structure is dominated by thick-skinned thrusting and folding, essentially by inversion of Mesozoic extensional faults and by buckling of both pre-Mesozoic basement and its sedimentary cover. Detached, thin-skinned thrusting is limited and apparently related to basement underthrusting, which did not always create structural relief. Despite the high topography, tectonic shortening is moderate, with faults and folds being spaced and separated by broad tabular areas. Section restoration indicates that shortening decreases along strike from east to west in the High Atlas, while topographic elevation generally increases. This inverse correlation suggests that crustal thickening does not fully explain the observed topography and suggests a mantle contribution to uplift. This is supported by geophysical indications of a thin lithosphere and by alkaline volcanism in the vicinity. Mantle-related uplift, which occurs in a broad region, may also explain the scarce foreland basin record adjacent to the High Atlas. The relief of the Atlas Mountains is interpreted as a combination of isostatic and dynamic topography.

Teixell, Antonio; Arboleya, Maria-Luisa; Julivert, Manuel; Charroud, Mohammed

2003-10-01

178

Wettability influences cell behavior on superhydrophobic surfaces with different topographies.  

PubMed

Surface wettability and topography are recognized as critical factors influencing cell behavior on biomaterials. So far only few works have reported cell responses on surfaces exhibiting extreme wettability in combination with surface topography. The goal of this work is to study whether cell behavior on superhydrophobic surfaces is influenced by surface topography and polymer type. Biomimetic superhydrophobic rough surfaces of polystyrene and poly(L-lactic acid) with different micro/nanotopographies were obtained from smooth surfaces using a simple phase-separation based method. Total protein was quantified and showed a less adsorption of bovine serum albumin onto rough surfaces as compared to smooth surfaces of the same material. The mouse osteoblastic MC3T3-E1 cell line and primary bovine articular chondrocytes were used to study cell attachment and proliferation. Cells attached and proliferate better in the smooth surfaces. The superhydrophobic surfaces allowed cells to adhere but inhibited their proliferation. This study indicates that surface wettability, rather than polymer type or the topography of the superhydrophobic surfaces, is a critical factor in determining cell behavior. PMID:22833364

Lourenço, Bianca N; Marchioli, Giulia; Song, Welong; Reis, Rui L; van Blitterswijk, Clemens A; Karperien, Marcel; van Apeldoorn, Aart; Mano, João F

2012-07-26

179

Measurement of seabed topography by multibeam sonar using CFFT  

Microsoft Academic Search

A precise ocean bottom map for ocean surveying and dredging is desired. Especially in dredging, it is essential to know the seabed topography in real time without being affected by scatterers (for example floating sand and mud) in the seawater during work. To meet these requirements, the multi-narrow-beam sonar system (MBSS) has been developed. The MBSS forms beams with the

MUTSUO OKINO; YOJI HIGASHI

1986-01-01

180

A BISTATIC ALTIMETRY MISSION FOR OCEAN TOPOGRAPHY MAPPING  

Microsoft Academic Search

Through a feasibility study funded by the European Space Agency (ESA), the authors analysed the possibility of using the innovative concepts of bistatic altimetry to enhance the spatial sampling of topography measurements over the oceans. Purpose of this paper is thus to review the major results of the mission design, focusing on the spacecraft configuration, mission analysis and the descripition

C. Zelli; M. Martin-Neira; G. Alberti; F. Impagnatiello; M. Matteoni

2010-01-01

181

High spatial resolution radar altimetry for global Earth topography mapping  

Microsoft Academic Search

This paper summarises the work performed by Alenia Aerospazio in the design of new radar altimeter systems suitable for high spatial resolution Earth topography observation. The instrument concept proposed is based on the application of synthetic aperture processing and interferometric techniques to a conventional Ku band pulse limited system. The major design features and expected performance are briefly presented

G. Angino; F. Impagnatiello; C. Zelli

1997-01-01

182

Topography of scalar fields: molecular clusters and ?-conjugated systems.  

PubMed

The pioneering works due to Bader and co-workers have generated widespread interest in the study of the topography of molecular scalar fields, the first step of which is the identification and characterization of the corresponding critical points (CPs). The topography of a molecular system becomes successively richer in going from the bare nuclear potential (BNP) to the molecular electrostatic potential (MESP) through the molecular electron density (MED). The present work clearly demonstrates, through the study of some ?-conjugated test molecules as well as molecular clusters, that the CPs could be economically located by following this path within ab initio level theory. Further, the topography mapping of large molecules, especially at a higher level of theory, is known to be a demanding task. However, it is rendered possible by following the above sequential mapping assisted by a divide-and-conquer-type method termed as the molecular tailoring approach (MTA). This is demonstrated with the topography mapping of ?-carotene and benzene nonamer at MP2 and a (H(2)O)(32) cluster at the HF level of theory, which are rather challenging problems with contemporary off-the-shelf computer hardware. PMID:21932861

Yeole, Sachin D; Gadre, Shridhar R

2011-09-21

183

Rapid topography mapping of scalar fields: large molecular clusters.  

PubMed

An efficient and rapid algorithm for topography mapping of scalar fields, molecular electron density (MED) and molecular electrostatic potential (MESP) is presented. The highlight of the work is the use of fast function evaluation by Deformed-atoms-in-molecules (DAM) method. The DAM method provides very rapid as well as sufficiently accurate function and gradient evaluation. For mapping the topography of large systems, the molecular tailoring approach (MTA) is invoked. This new code is tested out for mapping the MED and MESP critical points (CP's) of small systems. It is further applied to large molecular clusters viz. (H(2)O)(25), (C(6)H(6))(8) and also to a unit cell of valine crystal at MP2/6-31+G(d) level of theory. The completeness of the topography is checked by extensive search as well as applying the Poincaré-Hopf relation. The results obtained show that the DAM method in combination with MTA provides a rapid and efficient route for mapping the topography of large molecular systems. PMID:22920112

Yeole, Sachin D; López, Rafael; Gadre, Shridhar R

2012-08-21

184

A study of surface topography, friction and lubricants in metalforming  

Microsoft Academic Search

In this paper are presented the results of investigations concerning the relation between friction behaviour and surface topography using various lubricants and initial workpiece surface conditions in ring upsetting and rod extrusion processes. The tests were carried out using either a liquid lubricant or under clean dry conditions. Two types of workpiece surfaces, random and directional, were prepared by either

Z. M Hu; T. A Dean

2000-01-01

185

Role of Cigarette Sensory Cues in Modifying Puffing Topography  

PubMed Central

Background Human puffing topography promotes tobacco dependence by ensuring nicotine delivery, but the factors that determine puffing behavior are not well explained by existing models. Chemosensory cues generated by variations in cigarette product design features may serve as conditioned cues to allow the smoker to optimize nicotine delivery by adjusting puffing topography. Internal tobacco industry research documents were reviewed to understand the influence of sensory cues on puffing topography, and to examine how the tobacco industry has designed cigarettes, including modified risk tobacco products (MRTPs), to enhance puffing behavior to optimize nicotine delivery and product acceptability. Methods Relevant internal tobacco industry documents were identified using systematic searching with key search terms and phrases, and then snowball sampling method was applied to establish further search terms. Results Modern cigarettes are designed by cigarette manufacturers to provide sensory characteristics that not only maintain appeal, but provide cues which inform puffing intensity. Alterations in the chemosensory cues provided in tobacco smoke play an important role in modifying smoking behavior independently of the central effects of nicotine. Conclusions An associative learning model is proposed to explain the influence of chemosensory cues on variation in puffing topography. These cues are delivered via tobacco smoke and are moderated by design features and additives used in cigarettes. The implications for regulation of design features of modified risk tobacco products, which may act to promote intensive puffing while lowering risk perceptions, are discussed.

Rees, Vaughan W.; Kreslake, Jennifer M.; Wayne, Geoffrey Ferris; O Connor, Richard J.; Cummings, K. Michael; Connolly, Gregory N.

2012-01-01

186

Analysis of Multiple Manding Topographies during Functional Communication Training  

ERIC Educational Resources Information Center

|We evaluated the effects of reinforcing multiple manding topographies during functional communication training (FCT) to decrease problem behavior for three preschool-age children. During Phase 1, a functional analysis identified conditions that maintained problem behavior for each child. During Phase 2, the children's parents taught them to…

Harding, Jay W.; Wacker, David P.; Berg, Wendy K.; Winborn-Kemmerer, Lisa; Lee, John F.; Ibrahimovic, Muska

2009-01-01

187

Fabrication of cell container arrays with overlaid surface topographies  

Microsoft Academic Search

This paper presents cell culture substrates in the form of microcontainer arrays with overlaid surface topographies, and a technology for their fabrication. The new fabrication technology is based on microscale thermoforming of thin polymer films whose surfaces are topographically prepatterned on a micro- or nanoscale. For microthermoforming, we apply a new process on the basis of temporary back moulding of

R. K. Truckenmüller; S. Giselbrecht; M. Escalante; M. N. W. Groenendijk; B. J. Papenburg; N. C. Rivron; H. V. Unadkat; V. Saile; V. Subramaniam; Blitterswijk van C. A; M. Wessling; Boer de J; D. Stamatialis

2012-01-01

188

Left and right topography of F-actin filaments  

Microsoft Academic Search

F-actin filaments have been found to adopt conformations with both right handed and left handed topographies, as revealed by AFM imaging in air. The left handed conformation has not been observed previously by either AFM or electron microscopy. Either handedness can be produced by controlling the conditions under which the molecules are deposited for imaging by Scanning Force Microscopy or

Leda Chang; Fransiska S. Franke; Paula Flicker; David Keller

1995-01-01

189

Rapid topography mapping of scalar fields: Large molecular clusters  

NASA Astrophysics Data System (ADS)

An efficient and rapid algorithm for topography mapping of scalar fields, molecular electron density (MED) and molecular electrostatic potential (MESP) is presented. The highlight of the work is the use of fast function evaluation by Deformed-atoms-in-molecules (DAM) method. The DAM method provides very rapid as well as sufficiently accurate function and gradient evaluation. For mapping the topography of large systems, the molecular tailoring approach (MTA) is invoked. This new code is tested out for mapping the MED and MESP critical points (CP's) of small systems. It is further applied to large molecular clusters viz. (H2O)25, (C6H6)8 and also to a unit cell of valine crystal at MP2/6-31+G(d) level of theory. The completeness of the topography is checked by extensive search as well as applying the Poincaré-Hopf relation. The results obtained show that the DAM method in combination with MTA provides a rapid and efficient route for mapping the topography of large molecular systems.

Yeole, Sachin D.; López, Rafael; Gadre, Shridhar R.

2012-08-01

190

Automated comparisons of bullet striations based on 3D topography  

Microsoft Academic Search

A system capable of comparing the signatures on bullets in the field of firearms identification is presented. It is based on the recording of the topography of a bullet using laser profilometry. A procedure to derive a one-dimensional array of characteristics out of the recorded data is presented. These so-called feature vectors are compared with similar quantities from other bullets

Jan De Kinder; Monica Bonfanti

1999-01-01

191

Comparison of two common methods of surface-topography evaluation  

SciTech Connect

Some of the advantages and limitations of two methods used for surface topography evaluation, the dual beam interference microscope and the stylus type profiling instrument, are compared. Consideration is primarily limited to diamond machined or other high quality surfaces, such as are commonly encountered on optical elements. Parameters discussed include horizontal and vertical resolution, horizontal and vertical range, and surface damage.

Gauler, A.L.

1981-01-01

192

Global Topography of Titan from Cassini RADAR Data (Invited)  

NASA Astrophysics Data System (ADS)

Cassini RADAR data are used to construct a global, albeit sparsely-sampled, topography map, and to generate a hypsometric profile to compare with other planetary bodies. Titan’s hypsogram is unimodal and strikingly narrow compared with the terrestrial planets. To investigate topographic extremes, a novel variant on the classic hypsogram is introduced, with a logarithmic abscissa to highlight mountainous terrain. In such a plot, the top of the terrestrial hypsogram is quite distinct from those of Mars and Venus due to the ‘glacial buzz-saw’ that clips terrestrial topography above the snowline. In contrast to the positive skew seen in other hypsograms, with a long tail of positive relief due to mountains, there is an indication (weak, given the limited data for Titan so far) that the Titan hypsogram appears slightly negatively skewed, suggesting a significant population of unfilled depressions. Limited data permit only a simplistic comparison of Titan topography with other icy satellites but we find that the standard deviation of terrain height (albeit at different scales) is similar to those of Ganymede and Europa. The topography of terrestrial planets is sampled with the same coverage that we have for Titan to gauge what as-yet-undiscovered topographic surprises may yet be hidden by Titan’s haze.

Lorenz, R. D.; Cassini RADAR Team

2010-12-01

193

Admittance Computations from Lunar Gravity and Topography Data  

Microsoft Academic Search

The admittance transfer function, calculated from the gravity and topography data in the spectral domain, can be used to compute the elastic thickness of a terrestrial planet, the effective thickness of the part of the lithosphere that can support elastic stresses over long time scales. This has been applied extensively in recent years to Venus and Mars due to new

S. Asmar; G. Schubert

2002-01-01

194

Crustal structure of Mars from gravity and topography  

Microsoft Academic Search

(1) Mars Orbiter Laser Altimeter (MOLA) topography and gravity models from 5 years of Mars Global Surveyor (MGS) spacecraft tracking provide a window into the structure of the Martian crust and upper mantle. We apply a finite-amplitude terrain correction assuming uniform crustal density and additional corrections for the anomalous densities of the polar caps, the major volcanos, and the hydrostatic

G. A. Neumann; M. T. Zuber; M. A. Wieczorek; P. J. McGovern; F. G. Lemoine; D. E. Smith

2004-01-01

195

A novel digital x-ray topography system  

Microsoft Academic Search

X-ray topography (XRT) is recognized as being a powerful tool for directly imaging defects in single crystals, semiconductor wafers and epitaxially grown layers. The timely identification of defects can lead to increased yields and significant cost savings in wafer processing. The primary limitation to its general usage within the semiconductor community has been the difficulty in system use and difficulty

D. K. Bowen; M. Wormington; P. Feichtinger

2003-01-01

196

Instrumentation at National Facilities for Synchrotron Radiation Topography.  

National Technical Information Service (NTIS)

Synchrotron Radiation (SR) Topography is, like most SR experiments, small science carried out on a big science machine. This is a relatively new phenomenon in applied science and causes some disorientation in both the users and the funding agencies. The u...

D. K. Bowen J. C. Bilello

1983-01-01

197

Effects of volcano topography on seismic broad-band waveforms  

Microsoft Academic Search

Volcano seismology often deals with rather shallow seismic sources and seismic stations deployed in their near field. The complex stratigraphy on volcanoes and near-field source effects have a strong impact on the seismic wavefield, complicating the interpretation techniques that are usually employed in earthquake seismology. In addition, as most volcanoes have a pronounced topography, the interference of the seismic wavefield

Jürgen Neuberg; Tim Pointer

2000-01-01

198

Seismic wave simulation in the presence of real volcano topography  

Microsoft Academic Search

We use a finite-difference method on a 3-D staggered grid to simulate seismic wave propagation in the presence of strong topographic variations. An application to Merapi volcano, Indonesia, is presented. In order to focus on the effect of topography on the seismic wave field, calculations are performed for a rather simple model with an isotropic point source and a homogeneous

J. Ripperger; H. Igel; J. Wasserman

2003-01-01

199

Spatial patterns of precipitation and topography in the Himalaya  

Microsoft Academic Search

Spatial variability in precipitation has received little attention in the study of connections between climate, erosion, and tectonics. However, long-term precipita- tion patterns show large variations over spatial scales of ~10 km and are strongly controlled by topography. We use precipitation rate estimates from Tropical Rainfall Measuring Mission (TRMM) satellite radar data to approximate annual precipita- tion over the Himalaya

Alison M. Anders; Gerard H. Roe; Bernard Hallet; David R. Montgomery; Noah J. Finnegan; Jaakko Putkonen

200

Coupled Evolution of Topography and Orographic Precipitation in Varied Climates  

NASA Astrophysics Data System (ADS)

Landscapes respond to climate change. However, even in the absence of external drivers of climate change, topography and regional climate evolve together over timescales of thousands to millions of years. Topography itself is a strong control on precipitation patterns and produces persistent precipitation gradients of 150-500 percent over spatial scales of 5-30 km. As precipitation fundamentally affects the ability of rivers and glaciers to erode, these same precipitation gradients directly influence topographic development. A coupled model of landscape evolution and orographic precipitation is used to explore the co-evolution of climate and topography under a range of climatic conditions. The CASCADE landscape evolution model simulates fluvial erosion with a threshold slope condition over a uniformly uplifting surface. An orographic precipitation model simulates flow over topography and the production and advection of precipitation particles. The delay time (timescale for advection of precipitation from its formation until it reaches the land surface) is a strong control on the steady-state landscape form produced by the coupled model. Delay time controls the peak elevation, hypsometric integral, channel concavity and ridge-valley relief in modeled landscapes. These results indicate that in addition to the clear impact of precipitation amounts on topography, spatial patterns of precipitation - which are controlled by delay time - also strongly influence topography. The delay time can be interpreted to represent the temperature of the region. Short delay times are consistent with fast-falling rain and a warm climate. Long delay times are consistent with climates in which precipitation falls more slowly, as snow, for a large portion of its descent. Thus, large differences in peak elevation, hypsometry, channel concavity and ridge-valley relief are predicted in different climatic settings. Moreover, a transition from a snow-dominated to a rain-dominated climate is predicted to increase peak elevation and channel concavity. This behavior is simply due to a shift in the spatial pattern of precipitation and lacks consideration of a transition from fluvial to glacial erosion. Further research is needed to refine understanding of the impact of spatial patterns of precipitation on landscape evolution, but initial results demonstrate that spatial variability in precipitation and its relationship to topography has a strong impact on both mountain geomorphology and moutain climates.

Anders, A. M.

2006-12-01

201

A novel parameter proposed for 2D and 3D topography measurements and comparisons  

Microsoft Academic Search

Based on the cross-correlation function (CCF), a new parameter called profile difference, Ds (or topography difference for 3D), is developed for measurement and comparison of 2D profiles and 3D topographies. When Ds = 0, the two compared profiles or topographies must be exactly the same (point by point). A 2D and 3D topography measurement system was established at the National

John Song; Ted Vorburger

2007-01-01

202

Fractal mapping of digitized images - Application to the topography of Arizona and comparisons with synthetic images  

Microsoft Academic Search

The concept of fractal mapping is introduced and applied to digitized topography of Arizona. It is shown that the fractal statistics satisfy the topography of the state to a good approximation. The fractal dimensions and roughness amplitudes from subregions are used to construct maps of these quantities. It is found that the fractal dimension of actual two-dimensional topography is not

J. Huang; D. L. Turcotte

1989-01-01

203

Topography and the water cycle in a temperate middle mountain environment: the need for interdisciplinary experiments  

Microsoft Academic Search

Two main characteristics of mountainous regions are the large topography-driven lateral redistributions of water and energy, and the considerable topography-related heterogeneities on all scales. These features are difficult to estimate, to incorporate into hydrologic models and to aggregate on the general circulation model grid scale. On the local scale, the topography controls the spatial patterns of water and energy inputs,

Bruno Ambroise

1995-01-01

204

Iceland, the Farallon slab, and dynamic topography of the North Atlantic  

Microsoft Academic Search

Upwelling or downwelling flow in Earth's mantle is thought to elevate or depress Earth's surface on a continental scale. Direct observation of this ''dynamic topography'' on the seafloor, however, has remained elusive because it is obscured by isostatically sup- ported topography caused by near-surface density variations. We calculate the nonisostatic topography of the North Atlantic by correcting seafloor depths for

Clinton P. Conrad; Carolina Lithgow-Bertelloni; Keith E. Louden

2004-01-01

205

SRTM and Laser Altimeter Views of Western Washington State Topography  

NASA Astrophysics Data System (ADS)

Interferometric Synthetic Aperture Radar (InSAR) and laser altimeter measurements of topography provide complimentary approaches to characterize landforms. Results from the Shuttle Radar Topography Mission (SRTM) will provide an unprecedented, near-global, public-domain topography data set at 90 m resolution using a single pass C-band (5.6 cm wavelength) radar interferometer. In vegetated terrains, the C-band radar energy will penetrate part way into vegetation cover. The elevation of the resulting radar phase center, somewhere between the canopy top and underlying ground, will depend on the vegetation density, structure, and presence or absence of foliage. The high vertical accuracy and spatial resolution achieved by laser altimeters, and their capability to directly measure vegetation height and ground topography beneath vegetation cover, provides a method to evaluate InSAR representations of topography. Here a preliminary C-band SRTM digital elevation model (DEM) for a portion of western Washington State is evaluated using laser altimeter data to assess its elevation accuracy and the extent of vegetation penetration. The SRTM DEM extends from the Cascades Range westward to the Olympic Peninsula. The laser altimeter data includes two profiles acquired by the second flight of the Shuttle Laser Altimeter (SLA-02) in August, 1997, numerous transects acquired by the airborne Scanning Lidar Imager of Canopies by Echo Recovery (SLICER) in September, 1995, and comprehensive mapping in the Puget Lowland region acquired by Terrapoint, LLC for the Puget Sound Lidar Consortium in the winters of 2000 and 2001. SLA-02 and SLICER acquired waveforms that record the height distribution of illuminated surfaces within 120 m and 10 m diameter footprints, respectively. The Terrapoint elevations consist of up to four discrete returns from 1 m footprints spaced 1.5 apart, with all areas mapped twice. Methods for comparing laser altimeter and SRTM topography developed here will be applied on a global basis as Ice, Cloud and land Elevation Satellite and Vegetation Canopy Lidar laser altimeter waveform data and final SRTM products become available.

Harding, D. J.; Carabajal, C. C.

2001-12-01

206

Spatial and Temporal variability in Dynamic Topography in East Antarctica  

NASA Astrophysics Data System (ADS)

Recent aerogeophysical exploration has provided novel views of the Gamburtsev Subglacial Mountains and the Wilkes and Aurora subglacial basins in East Antarctica. Reconstructing the evolution of East Antarctic topography through time is a critical next step for developing new coupled climate and ice sheet models (e.g. http://www.antscape.org/). Insights into tectonic and isostatic components driving the uplift of the Gamburtsevs have emerged from geophysical investigations and modeling (Ferraccioli et al., 2011, Nature). However, our knowledge of the larger-scale consequences of dynamic topography in East Antarctica remains poor compared to other continents. Seismic tomographic models provide a tool to derive large-scale models of convection in the Earth's mantle, which can then be used to reconstruct dynamic topography through time. By analyzing grids of global dynamic topography from present-day to 100 Ma based on the tomographic models S40RTS & S20RTS (Ritsema et al. 1999, 2011) we assess for the first time the potential space-time variability in dynamic topography in East Antarctica. We acknowledge that there are significant limitations when compared to similar studies over other continents, such as the relatively poor seismic resolution of the lithosphere and asthenosphere beneath East Antarctica and the lack of geological and geophysical data to constrain surface movements through time. However, currently available global datasets do reveal several new insights. Our models reveal that at ca 65 Ma the Gamburtsev Province and Dronning Maud Land regions were elevated. This was followed by at least 500 m of subsidence throughout the Cenozoic. The increased regional elevation likely facilitated ephemeral ice cap development in the early Cenozoic, which was followed by ice cap coalescence to form the East Antarctic Ice Sheet at ca 34 Ma. In contrast, a major and more rapid increase in elevation (up to 1,000 m) is observed over the Transantarctic Mountains (TAM) and the adjacent Wilkes Subglacial Basin, in particular over the last 15 Ma. Neogene dynamic topography in the TAM region may be related to the flow of warm mantle from the West Antarctic Rift System and/or the Balleny plume.

Anderson, L.; Ferraccioli, F.; Eagles, G.; Steinberger, B.; Ritsema, J.

2012-04-01

207

Effects of dynamic topography on Australian Paleogeography in the Cenozoic  

NASA Astrophysics Data System (ADS)

We have investigated the effects of dynamic topography combined with eustatic sea level variations on Australian paleogeography for the Late Cretaceous to present. Using an analytical flow model (Steinberger et al., 2001, doi: 10.1016/S0012-821X(01)00229-1 with the surface plate velocity field as boundary condition, we advect density anomalies converted from tomographic velocity anomalies (SMEAN tomographic model; Becker &Boschi, 2002, doi: 10.1029/2001GC000168) back through time. For each time step, we compute dynamic topography with a free upper boundary. This approach allows us to evaluate the spatio-temporal effects of large scale mantle convection patterns on surface processes like continental flooding and sediment deposition. The Australian continent, especially the southern Australian margin, provides a unique example for an extensive region that has been stable and fairly isolated from plate boundary processes like flexure or rift shoulder uplift for the time between 70 Ma to the present. This makes it ideal to investigate the effects of dynamic topography. Late Cretaceous and Cenozoic sedimentary deposits along the southern Australian margin indicate transgressive/regressive phases of limited extent, which can not be explained by eustatic sea level fluctuations alone. By using common estimates for the eustatic sea level in conjunction with our dynamic topography model, we have been able to reconstruct the position of the Australian paleo-shorelines, flooding patterns and water depths. We find a good agreement of our computed paleogeography with published stratigraphic data for Tertiary brown coal deposits along the southern Australian seabord (Gippsland, Murray, Otway and Bremer Basins) and stratigraphic sequences in the Murray Basin region, along the NW Australian margin and in the Eromanga Basin. Despite minor spatial discrepancies between the current model output and geological data which yet remain unresolved, our approach and modular workflow set up provides an important stepping stone to understand the influence of deep Earth processes and their impact on sediment deposition and other geomorphological processes. Due to the usage of non-proprietary data formats and open-source software it is possible to easily change the dynamic topography model input and extend the computations to incorporate the effects of sedimentation history and isostasy. We expect a further convergence of predicted paleogeography from dynamic topography models with increasing accuracy and resolution of tomographic models.

Heine, C.; M{Ü}Ller, R.; Steinberger, B.

2006-12-01

208

Irregular topography at the Earth's inner core boundary.  

PubMed

Compressional seismic wave reflected off the Earth's inner core boundary (ICB) from earthquakes occurring in the Banda Sea and recorded at the Hi-net stations in Japan exhibits significant variations in travel time (from -2 to 2.5 s) and amplitude (with a factor of more than 4) across the seismic array. Such variations indicate that Earth's ICB is irregular, with a combination of at least two scales of topography: a height variation of 14 km changing within a lateral distance of no more than 6 km, and a height variation of 4-8 km with a lateral length scale of 2-4 km. The characteristics of the ICB topography indicate that small-scale variations of temperature and/or core composition exist near the ICB, and/or the ICB topographic surface is being deformed by small-scale forces out of its thermocompositional equilibrium position and is metastable. PMID:22547788

Dai, Zhiyang; Wang, Wei; Wen, Lianxing

2012-04-30

209

Crustal thinning and topography at passive continental margins  

NASA Astrophysics Data System (ADS)

There is a relationship between crustal thinning patterns and onshore topography at passive continental margins. This relationship appears to be governed principally by the crustal thinning gradient (taper) of the crystalline crust from unrifted crustal thickness down to a thickness less than 10 km. Surprisingly, the relationship appears to hold for very long time intervals (> 150 ma) after rifting and breakup. Offshore Norway, two end-member styles of crustal thinning are observed. Along the Møre margin, a basin-flank detachment complex thinned the crust dramatically from c. 40 to less than 10 km over a horizontal distance of < 100 km. Along the Trøndelag Platform, however, thinning down to less than 10 km was distributed between 2-3 large-magnitude normal faults over a much broader region, which evolved into platform and terrace areas. The location, displacement magnitude and lateral arrangement of faults that developed in the margi?s `thinnin? phase governed the position of the proximal-distal margin boundary and thus the gross-scale thinning gradient, or taper, of the crystalline crust. In the onshore areas, the effects on topography, landscape and fault reactivation patterns are profound. The highest escarpment and the most asymmetric margin topography developed inboard of sharply tapering crystalline crust. Inboard of sharp tapers, strong landscape contrasts developed across lineaments that were reactivated after the main phase of Mesozoic rifting, but prior to the glaciations. Glacial erosion enhanced tectonically induced drainage patterns, resulting in an asymmetric landscape distribution with high-relief alpine topography preferentially developed on the footwall sides of reactivated faults. This, in turn, pre-destined these landscapes to increased rockslide susceptibility because in the deeply incised escarpment topography, glacial incision undercut structures that had been reactivated in the brittle mode. The above relationships indicate that extensional faulting exerts a long-term control on escarpment topography, landscape contrasts, geohazard susceptibility and sediment routing patterns along passive margins, through the establishment of the taper. On more than 40 published profiles through passive margins, we have measured the distance from the taper break (where the crust is thinned to 10 km or less) to the point of maximum topographic elevation on the adjacent escarpment (apparent taper length) and plotted it against the maximum escarpment elevation measured on each profile. Our analysis indicates that breakup age, glaciations and calculated mantle effects are all subordinate to the taper in controlling escarpment topography. Also, substituting the taper break with the COB does not yield a particularly tight relationship. These observations indicate that it is the thinning of continental crystalline crust down to <10 km and not the replacement of continental with oceanic crust that matters for the topography of the escarpment. Moreover, sharp reductions in the thickness of crystalline crust from <30 km down to less than 10 km do not appear to produce long-standing escarpments.

Terje Osmundsen, Per; Redfield, Thomas F.; Ebbing, Jörg

2010-05-01

210

Geoid, topography, and convection-driven crustal deformation on Venus  

NASA Astrophysics Data System (ADS)

High-resolution Magellan images and altimetry of Venus reveal a wide range of styles and scales of surface deformation that cannot readily be explained within the classical terrestrial plate tectonic paradigm. The high correlation of long-wavelength topography and gravity and the large apparent depths of compensation suggest that Venus lacks an upper-mantle low-viscosity zone. A key difference between Earth and Venus may be the degree of coupling between the convecting mantle and the overlying lithosphere. Mantle flow should then have recognizable signatures in the relationships between the observed surface topography, crustal deformation, and the gravity field. Therefore, comparison of model results with observational data can help to constrain such parameters as crustal and thermal boundary layer thicknesses as well as the character of mantle flow below different Venusian features. We explore in this paper the effects of this coupling by means of a finite element modelling technique.

Simons, Mark; Hager, Bradford H.; Solomon, Sean C.

1993-03-01

211

Topography and refractometry of nanostructures using spatial light interference microscopy.  

PubMed

Spatial light interference microscopy (SLIM) is a novel method developed in our laboratory that provides quantitative phase images of transparent structures with a 0.3 nm spatial and 0.03 nm temporal accuracy owing to the white light illumination and its common path interferometric geometry. We exploit these features and demonstrate SLIM's ability to perform topography at a single atomic layer in graphene. Further, using a decoupling procedure that we developed for cylindrical structures, we extract the axially averaged refractive index of semiconductor nanotubes and a neurite of a live hippocampal neuron in culture. We believe that this study will set the basis for novel high-throughput topography and refractometry of man-made and biological nanostructures. PMID:20081970

Wang, Zhuo; Chun, Ik Su; Li, Xiuling; Ong, Zhun-Yong; Pop, Eric; Millet, Larry; Gillette, Martha; Popescu, Gabriel

2010-01-15

212

A study on Ganymede's surface topography: Perspectives for radar sounding  

NASA Astrophysics Data System (ADS)

Radar sounding of Jovian icy satellites has great potential to address specific science questions such as the presence of subsurface liquid water. Radargrams acquired over Mars polar caps allow observing clear echoes up to kilometers depth. However, Jovian icy satellites display dramatically different surface topographies. In order to assess possible issues arising from such surface topographies on radar sounding, we performed a study on different DEMs (Digital Elevation Models) obtained on Ganymede. Topographic data are derived using stereo and photoclinometric analysis of Galileo and Voyager images at resolutions of 16-629 m. Main results are presented in this paper. Overall we found that Ganymede's surface is quite rough, with mean slopes at 630 m scale varying from 3.5° to 8°, smoothest terrains being found within sulcii. This will be a major challenge for the design of radar sounders and parameters should be chosen accordingly in order to correctly sound this planetary body. Previous studies have shown similar concern for Europa.

Berquin, Y.; Kofman, W.; Herique, A.; Alberti, G.; Beck, P.

2013-03-01

213

Analysis of Multiple Manding Topographies during Functional Communication Training.  

PubMed

We evaluated the effects of reinforcing multiple manding topographies during functional communication training (FCT) to decrease problem behavior for three preschool-age children. During Phase 1, a functional analysis identified conditions that maintained problem behavior for each child. During Phase 2, the children's parents taught them to request positive reinforcers (attention or toys) via vocal manding, manual signing, or touching a picture/word card with or without a microswitch recording device. A non-concurrent multiple-baseline design across children was used to evaluate FCT outcomes. Results showed that problem behavior decreased for all three children. Results also indicated that the children initially used multiple manding topographies but displayed a preference for vocal manding over time. PMID:20354591

Harding, Jay W; Wacker, David P; Berg, Wendy K; Winborn-Kemmerer, Lisa; Lee, John F; Ibrahimovic, Muska

2009-02-01

214

Defect Analysis in Crystals using X-ray Topography  

SciTech Connect

A brief review of X-ray topography - a nondestructive method for direct observation and characterization of defects in single crystals - is presented here. The origin and development of this characterization method and the different techniques derived from it are described. Emphasis is placed on synchrotron X-ray topography and its application in studying various crystal imperfections. Mechanisms of contrast formation on X-ray topographs are discussed, with emphasis on contrast associated with dislocations. Determination of Burgers vectors and line directions of dislocations from analysis of X-ray topographs is explained. Contrast from inclusions is illustrated, and their differentiation from dislocations is demonstrated with the aid of simulated topographs. Contrast arising from the deformation fields associated with cracks is also briefly covered.

Raghothamachar,B.; Dhanaraj, G.; Bai, J.; Dudley, M.

2006-01-01

215

Resonant flow of a stratified fluid over topography  

Microsoft Academic Search

The flow of a stratified liquid over topography is considered in the long-wavelength weakly nonlinear limit for the case when the flow is near resonance; that is, the basic flow speed is close to a linear long-wave phase speed for one of the long-wave modes. It is shown that the amplitude of this mode is governed by a forced Korteweg-de

R. H. J. Grimshaw; N. F. Smyth

1986-01-01

216

TEM simulation with topography using boundary-fitted grid  

Microsoft Academic Search

Finite-Difference Time-Domain (FDTD) method has been successfully used in transient electromagnetic (TEM) simulation. Until recently, however, topography seems to be commonly neglected. To assess the topographic effect in TEM, some authors used a staircase approximation to the earth-air interface. But this approach might have two problems: first, its error might be very large; second, since air layer is explicitly included

D. Li; Q. Huang

2009-01-01

217

Some Bristol–Prague explorations in x-ray topography  

Microsoft Academic Search

This paper briefly chronicles a long-standing and productive collaboration between the Institute of Physics, Czech Academy of Science and the H H Wills Physics Laboratory. It began in early 1962 with a brief visit to Bristol by Milena Polcarov. The initial aim, successfully achieved, was the mapping by transmission topography of dislocations in melt-grown single crystals of a Fe–Si alloy.

A R Lang

2005-01-01

218

Channel network extraction from high resolution topography using wavelets  

Microsoft Academic Search

The availability of high resolution topography from LIDAR offers new opportunities for objectively extracting the channels directly from a DEM using local topographic information, instead of inferring them indirectly based on global criteria, such as area or area-slope threshold relationships. Here we introduce the use of wavelet filtering to delineate threshold curvatures for defining valleys and threshold slope-direction-change for defining

Bruno Lashermes; Efi Foufoula-Georgiou; William E. Dietrich

2007-01-01

219

Lunar Topography and Crustal Thickness by KAGUYA (SELENE) Selenodesy Observation  

Microsoft Academic Search

The Japanese lunar explorer KAGUYA (SELENE) was launched on September 14th, 2007 and continued its operation by June 11th, 2009. Laser altimeter(LALT) on board KAGUYA obtained the first precise global topography data with range accuracy of 5m [1]. In the polar regions where CLEMENTINE LIDAR could not obtain data, KAGUYA clarified topographic features including permanently shadowed areas. Distribution of solar

Sho Sasaki; Y. Ishihara; H. Araki; H. Noda; S. Goossens; N. Namiki; T. Iwata; H. Hanada; K. Matsumoto; N. Kawano; F. Kikuchi; Q. Liu; Y. Harada

2009-01-01

220

Research progress on the ultra hydrophobic surface topography effect  

Microsoft Academic Search

Ultra hydrophobic surfaces take on better hydrophobicity and exhibit a water contact angle larger than 150. In this paper\\u000a the ultra hydrophobicity is analyzed and common fabrication methods are summarized in detail. The applications of micro topography\\u000a in both the fabrication of hydrophobic surface and the experiments of drag reduction are addressed. Finally, the development\\u000a trend and foreground of ultra

Jiadao Wang; Ying Yu; Darong Chen

2006-01-01

221

The chemistry, morphology, topography of titanium carbide modified carbon fibers  

Microsoft Academic Search

Titanium carbide coatings were successfully applied on carbon fibers using reactive chemical vapor deposition approach. Chemistry, morphology, and topography of the TiC modified carbon fibers have been studied by scanning electron microscopy\\/energy dispersive spectroscopy, atomic force microscopy, and X-ray diffraction analysis. Uniform, adherent, crack-free and non-bridging coatings were obtained. After application of the TiC coating on carbon fibers, relief becomes

N. I. Baklanova; B. N. Zaitsev; A. T. Titov; T. M. Zima

2008-01-01

222

Geostatistical downscaling of fracture surface topography accounting for local roughness  

Microsoft Academic Search

This study proposes a new geostatistical methodology that accounts for roughness characteristics when downscaling fracture\\u000a surface topography. In the proposed approach, the small-scale fracture surface roughness is described using a “local roughness\\u000a pattern” that indicates the relative height of a location compared to its surrounding locations, while the large-scale roughness\\u000a is considered using the surface semivariogram. By accounting for both

Hirotaka Saito; Giovanni Grasselli

2010-01-01

223

Towards Mapping the Ocean Surface Topography at 1 KM Resolution  

NASA Astrophysics Data System (ADS)

We propose to apply the technique of synthetic aperture radar interferometry to the measurement of ocean surface topography at spatial resolu tion approaching 1 km . The measurement w ill have wide ranging applications in oceanography , hydrology , and marine geophysics. The oceanographic and related societal applications are briefly discussed in the paper. To meet the requirements for oceanographic application s, the in strument must be flown in an orbit w ith proper samp ling of ocean tides.

Fu, L. L.; Rodriguez, E.

2006-07-01

224

Strength of Faults on Mars from MOLA Topography  

Microsoft Academic Search

The stresses which must be maintained on faults bounding the rift topography at Tempe Fossae—the “North Tempe Rift” (NTR)—and Valles Marineris (VM) on Mars are estimated, using a simple elastic model and topographic data from the Mars Orbiter Laser Altimeter (MOLA). The absence of rift-flank uplift at the NTR is consistent with an elastic thickness, Te, of 20 km or

David N. Barnett; Francis Nimmo

2002-01-01

225

Effect of topography on ground movement due to longwall mining  

SciTech Connect

This paper presents an analysis of the effects of topography on static and dynamic ground movements and severity of damage inflicted on surface structures. A typical site containing varying topographical features (i.e., mountains, hillsides, valleys, and flat bottom land) representing the northern Appalachian region was chosen for the study. Typical subsidence monitoring techniques were employed. Frequent measurements were made as the face advanced.

Khair, A.W.; Quinn, M.K.; Chaffins, R.D.

1988-08-01

226

Anomalous topography on the continental shelf around Hudson Canyon  

USGS Publications Warehouse

Recent seismic-reflection data show that the topography on the Continental Shelf around Hudson Canyon is composed of a series of depressions having variable spacings (< 100 m to 2 km), depths (1-10 m), outlines, and bottom configurations that give the sea floor an anomalous "jagged" appearance in profile. The acoustic and sedimentary characteristics, the proximity to relict shores, and the areal distribution indicate that this rough topography is an erosional surface formed on Upper Pleistocene silty sands about 13,000 to 15,000 years ago by processes related to Hudson Canyon. The pronounced southward extension of the surface, in particular, may reflect a former increase in the longshore-current erosion capacity caused by the loss of sediments over the canyon. Modern erosion or nondeposition of sediments has prevented the ubiquitous sand sheet on the Middle Atlantic shelf from covering the surface. The "anomalous" topography may, in fact, be characteristic of areas near other submarine canyons that interrupt or have interrupted the longshore drift of sediments. ?? 1979.

Knebel, H. J.

1979-01-01

227

Quantification of the skin's topography by skin profilometry.  

PubMed

Synopsis A method of skin profilometry is presented. The data generated using this method are used to (a) uncover sources of variation in skin profilometry, (b) provide information regarding the choice of roughness parameters best suited for characterizing the skin's topography, and (c) determine if skin profilometry is a valuable tool for quantitatively assessing changes in the skin's surface pattern. The data show the roughness parameter values to be dependent on the orientation of the tracings with regard to the major grooves and ridges present in the surface patterns. Large variabilities of roughness parameter values obtained for multiple scans within small areas of replicas are indicative of the nonhomogeneity of the skin's surface. The number of peaks, mean peak size, mean depth of roughness, depth of smoothness, and residual profile length appear to be the most utile roughness parameters for quantifying changes in the skin's topography. The ability of skin profilometry to detect subtle changes in the skin's surface pattern due to hydration indicates the method is a sensitive means of quantifying the skin's topography. PMID:19469963

Cook, T H; Craft, T J; Brunelle, R L; Norris, F; Griffin, W A

1982-10-01

228

Cellular Scale Anisotropic Topography Guides Schwann Cell Motility  

PubMed Central

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.

Mitchel, Jennifer A.; Hoffman-Kim, Diane

2011-01-01

229

Biocompatibility of TiO2 nanotubes with different topographies.  

PubMed

The biological response of osteoblast cells to implant materials depends on the topography and physico-chemistry of the implant surface and this determines the cell behavior such as shaping, adhesion and proliferation, and finally the cell fate. In this study, titanium (Ti) was anodized to create different topographies of titania nanotubes (TNTs) to investigate the cell behavior to them. TNTs with and without a highly ordered nanoporous layer on their top surface were fabricated using two-step and one-step anodizing processes, respectively. The TNTs without a highly ordered nanoporous layer on the top surface exhibited a rougher surface, higher surface energy and better hydrophilicity than the TNTs with such a layer. Osteoblast-like cells (SaOS2) were used to assess the biocompatibility of the TNTs with different topographies in comparison to bare cp-Ti. Results indicated that TNTs can enhance the proliferation and adhesion of osteoblast-like cells. TNTs without a highly ordered nanoporous layer exhibited better biocompatibility than the TNTs covered by such a nanoporous layer. Cell morphology observation using confocal microscopy and SEM indicated that SaOS2 cells that were adhered to the TNTs without the highly ordered nanoporous layer showed the longest filopodia compared to TNTs with a highly ordered nanoporous layer and bare cp-Ti. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013. PMID:23554372

Wang, Yu; Wen, Cuie; Hodgson, Peter; Li, Yuncang

2013-04-01

230

Laboratory studies of pyroclastic flows that interact with topography  

NASA Astrophysics Data System (ADS)

We performed a set of scaled laboratory experiments to simulate pyroclastic density currents (PDCs) using dilute mixtures of warm talc powder in air. The experiments were designed to evaluate the effects of topography on current runout, buoyancy reversal and liftoff, and mass partitioning into buoyant plumes. The densimetric and thermal Richardson, Froude, Stokes, and settling numbers for our experiments match those of PDCs and the laboratory currents are fully turbulent, although the experiments have lower Reynolds numbers than PDCs, thus our experiments are dynamically similar to natural currents. Comparisons of currents traversing flat topography or encountering barriers shows that runout distance is not significantly reduced for currents that traverse barriers with height less than 1.5 times the current thickness, but currents do not pass taller barriers. Buoyancy reversals occur in most currents, resulting in liftoff and generation of a buoyant plume. Liftoff occurs near the maximum runout distance for currents traveling over flat topography, but is focused near or above barriers for currents that encounter barriers. Notably, plume formation above barriers can result in reversal of flow direction downstream of the obstruction as portions of the current flow back and feed the rising plume. Greater than half of the initial particle mass composing the density currents usually partitions into the buoyant plumes; that fraction is greater for currents that liftoff closer to the source, thus topographic barriers increase mass partitioning from currents into buoyant plumes.

Andrews, B.; Manga, M.

2012-04-01

231

Permian karst topography in the Wichita uplift, southwestern Oklahoma  

SciTech Connect

The Wichita uplift in southwestern Oklahoma is one part of a record of Pennsylvania and early Permian deformation that affected the Southern Oklahoma aulacogen. As a result of a partial inversion, the Lower Paleozoic section of this aulacogen was sequentially stripped off an uplift between the Wichita uplift and the Anadarko basin, resulting in the exposure of ultrabasic rocks deep in the Cambrian igneous fill of the aulacogen. Following the late Paleozoic tectonism, the topography of the uplift was entombed beneath Permian sediments and remained essentially undisturbed until exhumation during the present erosional cycle. Modern erosion is gradually exposing this topography, permitting morphometric analysis of the Permian hill forms. Because of the variation of lithology in the uplift, it is possible to isolate the effects of weathering processes such as intense hydrolysis of the igneous rocks (producing, among other features, or topography) and limestone dissolution, in the form of a surface and subsurface karst imprint. The latter process resulted in a network of small caves that are essentially fissures eroded along tectonic fractures. These small caves can be found in all the exposed areas of limestone. They are particularly noteworthy for three reasons: in at least five examples they contain a complex fauna of Permian vertebrates (mostly fragmentary), speleothems in some examples contain hydrocarbon inclusions, derived from the underlying Anadarko basin, some of the caves yield evidence of post burial evolution in the form of clay infiltration from the surface and brine flushing from the underlying Anadarko basin.

Donovan, R.N. Busbey, A.B. (Texas Christian Univ., Ft. Worth, TX (United States). Geology Dept.)

1993-02-01

232

Age and Prematurity of the Alps Derived from Topography  

NASA Astrophysics Data System (ADS)

The European Alps are one of the best studied mountain ranges on Earth, but yet the age of their topography is almost unknown. Even their relative stage of evolution is unclear: Are the Alps still growing, in a steady state or already decaying, and is there a significant difference between Western and Eastern Alps? Using a new geomorphic parameter we analyze the topography of the Alps and provide one of the first quantitative constraints demonstrating that the range is still in its infancy: In contrast to several other mountain ranges, the Alps have still more than half of their evolution to a geomorphic steady state to go. Combining our results with sediment budget data from the surrounding basins we infer that the formation of the present topography began only 5-6 million years ago. Our results question the apparent consensus that the topographic evolution is distributed over much of the Miocene and might give new impulses to the reconstruction of paleoclimate in Central Europe.

Hergarten, S.; Wagner, T.; Stüwe, K.

2010-09-01

233

Linking topography to tonotopy in the mouse auditory thalamocortical circuit  

PubMed Central

The mouse sensory neocortex is reported to lack several hallmark features of topographic organization such as ocular dominance and orientation columns in primary visual cortex or fine-scale tonotopy in primary auditory cortex (AI). Here, we re-examined the question of auditory functional topography by aligning ultra-dense receptive field maps from the auditory cortex and thalamus of the mouse in vivo with the neural circuitry contained in the auditory thalamocortical slice in vitro. We observed precisely organized tonotopic maps of best frequency (BF) in the middle layers of AI and the anterior auditory field (AAF) as well as in ventral and medial divisions of the medial geniculate body (MGBv, MGBm). Tracer injections into distinct zones of the BF map in AI retrogradely labeled topographically organized MGBv projections and weaker, mixed projections from MGBm. Stimulating MGBv along the tonotopic axis in the slice produced an orderly shift of voltage-sensitive dye (VSD) signals along the AI tonotopic axis, demonstrating topography in the mouse thalamocortical circuit that is preserved in the slice. However, compared to BF maps of neuronal spiking activity, the topographic order of sub-threshold VSD maps was reduced in layer IV and even further degraded in layer II/III. Therefore, the precision of AI topography varies according to the source and layer of the mapping signal. Our findings further bridge the gap between in vivo and in vitro approaches for the detailed cellular study of auditory thalamocortical circuit organization and plasticity in the genetically tractable mouse model.

Hackett, Troy A.; Barkat, Tania Rinaldi; O'Brien, Barbara MJ.; Hensch, Takao K.; Polley, Daniel B.

2011-01-01

234

Global snowline and mountain topography: a contrasted view  

NASA Astrophysics Data System (ADS)

The examination of the relationship between Earth's topography and present and past climate (i.e., long-term elevation of glaciers Equilibrium Line Altitude) reveals that the elevation of mountain ranges may be limited or controlled by glaciations (e.g. Porter, 1989). This is of prime importance, because glacial condition would lead to a limit the mountain development, hence the accumulation of gravitational energy and prevent the development of further glacial conditions as well as setting the erosion in (peri)glacial environments. In this study, we examine the relationships between topography and the global Equilibrium Line Altitude of alpine glaciers around the world (~ long term snowline, i.e. the altitude where the ice mass balance is null). This analysis reinforce a global study previously published (Champagnac et al., 2012), and provide a much finer view of the climate-topography-tectonics relationships. Specifically, two main observations can be drawn: 1) The distance between the (averaged and maximum) topography, and the ELA decreases pole ward the poles, and even become reversed (mean elevation above to ELA) at high latitude. Correlatively, the elevation of very large portion of land at mid-latitude cannot be related to glaciations, simply because it was never glaciated (large distance between topography and long-term mean ELA). The maximum distance between the ELA and the topography is greater close to the equator and decreases poleward. In absence of glacial and periglacial erosion, this trend cannot have its origin in glacial and periglacial processes. Moreover, the ELA elevation shows a significant (1000~1500m) depression in the intertropical zone. This depression of the ELA is not reflected at all in the topography 2) The distribution of relief on Earth, if normalized by the mean elevation of mountain ranges (as a proxy for available space to create relief, see Champagnac et al., 2012 for details) shows a latitudinal band of greater relief between ~40 and ~60° (or between ELA of ~500m to ~2500m a.s.l.). This mid-latitude relatively greater relief challenges the straightforward relationship between glaciations, erosion and topography. Oppositely, it suggests that glacier may be more efficient agent in temperate area, with an important amplitude between glacial and interglacial climate. This is consistent with the view of a very variable glacier erodibility that can erode and protect the landscape, as well as with studies documenting a bimodal location of the preferred glacial erosion, at relatively high elevation (around the long-term ELA), and at much lower elevation (close to the glacial maximum lower reaches), thanks to efficient water lubrication of the glacier bases that greatly enhance the sliding velocity (Herman et al., 2011). These findings show that the relation between the mountain topography and the long term snowline is not as straightforward as previously proposed (e.g. Egholm et al., 2009) . Beside the role of tectonic forcing highlighted by several authors (e.g. Pedersen et al., 2010;Spotila and Berger, 2010),, the importance of the glacial erosion appears to be crucial at mid latitude, but more complex at both high and low latitude. Moreover, the relief at mid latitude appears to be higher, hence suggesting a positive correlation between relief and topographic control of glacier on the landscape Champagnac, J.-D., Molnar, P., Sue, C., and Herman, F.: Tectonics, Climate, and Mountain Topography, Journal of Geophysical Research B: Solid Earth, 117, doi:10.1029/2011JB008348, 2012. Egholm, D. L., Nielsen, S. B., Pedersen, V. K., and Lesemann, J. E.: Glacial effects limiting mountain height, Nature, 460, 884-888, 2009. Herman, F., Beaud, F., Champagnac, J.-D., Lemieux, J.-M., and Sternai, P.: Glacial hydrology and erosion patterns: A mechanism for carving glacial valleys, Earth and Planetary Science Letters, 310, 498-508, 2011. Pedersen, V. K., Egholm, D. L., and Nielsen, S. B.: Alpine glacial topography and the rate of rock column uplift: a global perspective, Geomorphology, 122, 129-139, 10.1

Champagnac, Jean-Daniel; Herman, Frédéric; Valla, Pierre

2013-04-01

235

Dependence of the Fracture of PowerTrench MOSFET Device on Its Topography in Cu Bonding Process  

Microsoft Academic Search

Dependence of the fracture-resistance of a PowerTrench MOSFET device on its topography in Cu bonding process was investigated. Two different topographies, namely dimple and round, have been tested. A significantly higher cratering rate has been clearly observed on dimple topography. The dimple topography exhibited a cratering rate of 371 k ppm levels compared to 0 ppm in round topographies. Three-dimensional

Manmohan Daggubati; Q. Wang; Y. V. Sokolov; Yong Liu; Lu-Chang Qin

2009-01-01

236

Analysis on 3d Topography Effects on Magnetotelluric Responses  

NASA Astrophysics Data System (ADS)

Magnetotelluric (MT) surveys based on a natural electromagnetic induction in the Earth have been conducted to investigate geothermal resources in Pohang, Jeju Island, and Seokmo Island, Korea. Although some of the MT surveys indicated fracture systems through which relatively high-temperature fluid flows, the temperature is still not enough for a traditional geothermal power plant. However, even when natural convective hydrothermal resources are unavailable, an enhanced geothermal system (EGS), a new type of geothermal power technologies, can produce heat and electricity by harnessing the energy from hot rock at depths ranging from about 3 km to 10 km. This fact makes EGS a hot issue in Korea for geothermal power plant, even though EGS not only has lower capacity of power generation than the traditional one but also more expensive. As a starting stage of site characterization for EGS, which will be followed by temperature and stress estimation, precise interpretation of MT data distorted by irregular surface terrain is critical in Korea, since almost 70% of the land of Korea is mountainous terrain. This study investigates topography effects on MT responses, i.e., apparent resistivities, phases, tippers and induction vectors for a three-dimensional (3D) hill model. To calculate MT responses for a model with surface topography, we use a 3D MT modeling algorithm based on an edge finite-element method. Numerical experiments indicate that current distortion by surface topography affects MT responses such as apparent resistivites, phases, and tippers. Apparent resistivities in the xy mode are slightly higher than the background resistivity near hill slopes in the x-direction while the resistivities are smaller over the hill. Distortions on amplitudes of tippers over a hill are quite similar to those over a valley. The directions of tippers over a hill are toward the summit of the hill, while those over a valley are toward the base.

Nam, M.; Han, N.; Kim, H.; Song, Y.

2010-12-01

237

Spatial and temporal patterns of Cenozoic dynamic topography around Australia  

NASA Astrophysics Data System (ADS)

Despite its importance, the spatial and temporal pattern of dynamic topography generated by mantle convective circulation is poorly known. We present accurate estimates of dynamic topography from oceanic basins and continental margins surrounding Australia. Our starting point is measurement of residual depth anomalies on the oldest oceanic floor adjacent to the continental shelf. These anomalies were determined from a combined dataset of ~200 seismic reflection and wide-angle images of well-sedimented oceanic crust. They have amplitudes of between -1 km and +0.5 km, and their spatial variation is broadly consistent with long-wavelength free-air gravity and shallow seismic tomographic anomalies. Along the Northwest Shelf, a regional depth anomaly of -300 to -700 m intersects the adjacent continental shelf. The temporal evolution of this anomaly was determined by analyzing the stratigraphic architecture of an extensive carbonate platform, which fringes the shelf and records a dramatic switch from progradation to aggradation during Neogene times. Three-dimensional seismic mapping calibrated by boreholes was used to calculate water-loaded subsidence histories at rollover points of clinoforms along the shelf. At 9 ± 3 Ma, the rate of subsidence increases from 5 to up 75 m Myr-1, generating a subsidence anomaly of -300 to -700 m. The amplitude of this anomaly varies along the shelf and cannot be generated by glacio-eustatic sea-level variation. Instead, we propose that a regional subsidence episode, which affects both the proximal shelf and the distal oceanic basin, was generated by convective drawdown. By combining our results with other published estimates of uplift and subsidence, a map of Australia, which shows the spatial and temporal pattern of dynamic topography is presented. Most, but not all, of Australia's epeirogeny can be attributed to rapid northward motion of the Australian plate over a pre-existing pattern of convective circulation.

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

2013-03-01

238

Management Intensity and Topography Determined Plant Diversity in Vineyards  

PubMed Central

Vineyards are amongst the most intensive forms of agriculture often resulting in simplified landscapes where semi-natural vegetation is restricted to small scattered patches. However, a tendency toward a more sustainable management is stimulating research on biodiversity in these poorly investigated agro-ecosystems. The main aim of this study was to test the effect on plant diversity of management intensity and topography in vineyards located in a homogenous intensive hilly landscape. Specifically, this study evaluated the role of slope, mowing and herbicide treatments frequency, and nitrogen supply in shaping plant diversity and composition of life-history traits. The study was carried out in 25 vineyards located in the area of the Conegliano-Valdobbiadene DOCG (Veneto, NE Italy). In each vineyard, 10 plots were placed and the abundance of all vascular plants was recorded in each plot. Linear multiple regression was used to test the effect of management and topography on plant diversity. Management intensity and topography were both relevant drivers of plant species diversity patterns in our vineyards. The two most important factors were slope and mowing frequency that respectively yielded positive and negative effects on plant diversity. A significant interaction between these two factors was also demonstrated, warning against the detrimental effects of increasing mowing intensity on steep slope where plant communities are more diverse. The response of plant communities to mowing frequency is mediated by a process of selection of resistant growth forms, such in the case of rosulate and reptant species. The other two management-related factors tested in this study, number of herbicide treatments and N fertilization, were less influential. In general, our study corroborates the idea that some simple changes in farming activities, which are compatible with grape production, should be encouraged for improving the natural and cultural value of the landscape by maintaining and improving wild plant diversity.

Nascimbene, Juri; Marini, Lorenzo; Ivan, Diego; Zottini, Michela

2013-01-01

239

Management intensity and topography determined plant diversity in vineyards.  

PubMed

Vineyards are amongst the most intensive forms of agriculture often resulting in simplified landscapes where semi-natural vegetation is restricted to small scattered patches. However, a tendency toward a more sustainable management is stimulating research on biodiversity in these poorly investigated agro-ecosystems. The main aim of this study was to test the effect on plant diversity of management intensity and topography in vineyards located in a homogenous intensive hilly landscape. Specifically, this study evaluated the role of slope, mowing and herbicide treatments frequency, and nitrogen supply in shaping plant diversity and composition of life-history traits. The study was carried out in 25 vineyards located in the area of the Conegliano-Valdobbiadene DOCG (Veneto, NE Italy). In each vineyard, 10 plots were placed and the abundance of all vascular plants was recorded in each plot. Linear multiple regression was used to test the effect of management and topography on plant diversity. Management intensity and topography were both relevant drivers of plant species diversity patterns in our vineyards. The two most important factors were slope and mowing frequency that respectively yielded positive and negative effects on plant diversity. A significant interaction between these two factors was also demonstrated, warning against the detrimental effects of increasing mowing intensity on steep slope where plant communities are more diverse. The response of plant communities to mowing frequency is mediated by a process of selection of resistant growth forms, such in the case of rosulate and reptant species. The other two management-related factors tested in this study, number of herbicide treatments and N fertilization, were less influential. In general, our study corroborates the idea that some simple changes in farming activities, which are compatible with grape production, should be encouraged for improving the natural and cultural value of the landscape by maintaining and improving wild plant diversity. PMID:24098435

Nascimbene, Juri; Marini, Lorenzo; Ivan, Diego; Zottini, Michela

2013-10-01

240

The regulation of integrin-mediated osteoblast focal adhesion and focal adhesion kinase expression by nanoscale topography.  

PubMed

An important consideration in developing physical biomimetic cell-stimulating cues is that the in vivo extracellular milieu includes nanoscale topographic interfaces. We investigated nanoscale topography regulation of cell functions using human fetal osteoblastic (hFOB) cell culture on poly(l-lactic acid) and polystyrene (50/50 w/w) demixed nanoscale pit textures (14, 29, and 45nm deep pits). Secondary ion mass spectroscopy revealed that these nanotopographic surfaces had similar surface chemistries to that of pure PLLA because of PLLA component surface segregation during spin casting. We observed that 14 and 29nm deep pit surfaces increased hFOB cell attachment, spreading, selective integrin subunit expression (e.g., alphav relative to alpha5, beta1, or beta3), focal adhesive paxillin protein synthesis and paxillin colocalization with cytoskeletal actin stress fibers, and focal adhesion kinase (FAK) and phosphorylated FAK (pY397) expression to a greater degree than did 45nm deep pits or flat PLLA surfaces. Considering the important role of integrin-mediated focal adhesion and intracellular signaling in anchorage-dependent cell function, our results suggest a mechanism by which nanostructured physical signals regulate cell function. Modulation of integrin-mediated focal adhesion and related cell signaling by altering nanoscale substrate topography will have powerful applications in biomaterials science and tissue engineering. PMID:17218005

Lim, Jung Yul; Dreiss, Andrea D; Zhou, Zhiyi; Hansen, Joshua C; Siedlecki, Christopher A; Hengstebeck, Robert W; Cheng, Juan; Winograd, Nicholas; Donahue, Henry J

2006-12-21

241

Dynamic evaluation of facial palsy by moire topography video  

NASA Astrophysics Data System (ADS)

Several visual assessment methods have been proposed for evaluating facial nerve function. They are of value clinically, but they have drawbacks when objective, quantitative, and reproducible assessment is required. To solve these problems, we used moire topography, which helps visualize information in three dimensions. We previously reported that one could evaluate the severity of facial palsy by observing characteristic patterns of the moire strips produced by facial movement. Accordingly, we developed a new form of the dynamic evaluation by recording the dynamic changes in moire strip patterns on the face on a videotape.

Yuen, Koji; Inokuchi, Ikuo; Maeta, Manabu; Kawakami, Shinichiro; Masuda, Yu

1994-02-01

242

Barotropic flow over bottom topography— experiments and nonlinear theory  

NASA Astrophysics Data System (ADS)

Barotropic flow over finite amplitude two-wave bottom topography is investigated both experimentally and theoretically over a broad parameter range. In the experiments, the fluid is contained in a vertically oriented, rotating circular cylindrical annulus. It is forced into motion relative to the annulus by a differentially rotating, rigid, radially sloping lid in contact with the top surface of the fluid. The radial depth variation associated with the slope of the lid, and an equal and opposite slope of the bottom boundary, simulates the effect of the variation of the Coriolis parameter with latitude (?) in planetary atmospheres and in the ocean. The dimensionless parameters which control the fluid behavior are the Rossby number (?), the Ekman number (E), the ? parameter, the aspect ratio (?), the ratio of the mean radius to the gap width (?) and the ratio of the topographic height to the mean fluid depth (?). The Rossby and Ekman numbers are varied over an order of magnitude by conducting experiments at different rotation rates of the annulus. Velocity measurements using photographs of tracer particles suspended in the fluid reveal the existence of a stationary, topographically forced wave superimposed on an azimuthal mean current. With successively larger rotation rates (i.e. lower ? and E) the wave amplitude increases and then levels off, the phase displacement of the wave upstream of the topography increases and the azimuthal mean velocity decreases and then levels off. Linear quasigeostophic theory accounts qualitatively, but not quantitatively, for the phase displacement, predicts the wave amplitude poorly and provides no basis for predicting the zonal mean velocity. Accordingly, we have solved the nonlinear, steady-state, quasigeostrophic barotrophic vorticity equation with both Ekman layer and internal dissipation using a spectral colocation method with Fourier representation in the azimuthal direction and Chebyshev polynomial representation in the radial direction. For boundary conditions at the side walls, we specified zero velocity. Side wall boundary layers then appear explicitly in the numerical solution. At the bottom and top of the fluid, we specified that the vertical velocity at the mean height of each boundary is the sum of two components—one forced by Ekman suction in the absence of topography and the other by the condition that there can be no flow normal to the rigid boundary. We justify this choice by the smallness of the Ekman number and of the radial and azimuthal slopes of the topography. We have found that the use of three Fourier components and seven Chebyshev polynomials is sufficient to account qualitatively for the experimental results, although small quantitative discrepancies suggest that further investigation of the neglect of effects originally considered to be small is needed.

Pfeffer, Richard L.; Kung, Robin; Ding, Wen; Li, Guo-Qing

1993-10-01

243

X-ray topography of a crystal of tetragonal lysozyme  

NASA Astrophysics Data System (ADS)

A crystal of the tetragonal modification of lysozyme grown under controlled conditions with in situ monitoring of the growth kinetics and morphology of the (110) face is studied by X-ray topography using synchrotron radiation. The choice of a diffraction reflection with optimal dispersion allows us to obtain an informative X-ray topographic image of the sample. It is found that the striations that are formed under changing supersaturation correspond to the type of zonality characteristic of crystals growing by the normal mechanism and differ from those observed in inorganic crystals growing by the layer-by-layer mechanism.

Voloshin, A. E.; Kovalev, S. I.; Lyasnikova, M. S.; Mukhamedzhanov, E. Kh.; Borisov, M. M.; Koval'chuk, M. V.

2012-09-01

244

Topography of the Moon from the Clementine LIDAR  

NASA Astrophysics Data System (ADS)

Range measurements from the lidar instrument carried aboard the Clementine spacecraft have been used to produce an accurate global topographic model of the Moon. This paper discusses the function of the lidar; the acquisition, processing, and filtering of observations to produce a global topographic model; and the determination of parameters that define the fundamental shape of the Moon. Our topographic model: a 72nd degree and order spherical harmonic expansion of lunar radii, is designated Goddard Lunar Topography Model 2 (GLTM 2). This topographic field has an absolute vertical accuracy of approximately 100 m and a spatial resolution of 2.5 deg. The field shows that the Moon can be described as a sphere with maximum positive and negative deviations of approx. 8 km, both occurring on the farside, in the areas of the Korolev and South Pole-Aitken (S.P.-Aitken) basins. The amplitude spectrum of the topography shows more power at longer wavelengths as compared to previous models, owing to more complete sampling of the surface, particularly the farside. A comparison of elevations derived from the Clementine lidar to control point elevations from the Apollo laser altimeters indicates that measured relative topographic heights generally agree to within approx. 200 in over the maria. While the major axis of the lunar gravity field is aligned in the Earth-Moon direction, the major axis of topography is displaced from this line by approximately 10 deg to the cast and intersects the farside 24 deg north of the equator. The magnitude of impact basin topography is greater than the lunar flattening (approx. 2 km) and equatorial ellipticity (approx. 800 m), which imposes a significant challenge to interpreting the lunar figure. The floors of mare basins are shown to lie close to an equipotential surface, while the floors of unflooded large basins, except for S.P.-Aitken, lie above this equipotential. The radii of basin floors are thus consistent with a hydrostatic mechanism for the absence of significant farside maria except for S.P.-Aitken, whose depth and lack of mare require significant internal compositional and/or thermal heterogeneity. A macroscale surface roughness map shows that roughness at length scales of 101 - 102 km correlates with elevation and surface age.

Smith, David E.; Zuber, Maria T.; Neumann, Gregory A.; Lemoine, Frank G.

1997-01-01

245

Dynamic wetting and spreading and the role of topography.  

PubMed

The spreading of a droplet of a liquid on a smooth solid surface is often described by the Hoffman-de Gennes law, which relates the edge speed, v(e), to the dynamic and equilibrium contact angles ? and ?(e) through [Formula: see text]. When the liquid wets the surface completely and the equilibrium contact angle vanishes, the edge speed is proportional to the cube of the dynamic contact angle. When the droplets are non-volatile this law gives rise to simple power laws with time for the contact angle and other parameters in both the capillary and gravity dominated regimes. On a textured surface, the equilibrium state of a droplet is strongly modified due to the amplification of the surface chemistry induced tendencies by the topography. The most common example is the conversion of hydrophobicity into superhydrophobicity. However, when the surface chemistry favors partial wetting, topography can result in a droplet spreading completely. A further, frequently overlooked consequence of topography is that the rate at which an out-of-equilibrium droplet spreads should also be modified. In this report, we review ideas related to the idea of topography induced wetting and consider how this may relate to dynamic wetting and the rate of droplet spreading. We consider the effect of the Wenzel and Cassie-Baxter equations on the driving forces and discuss how these may modify power laws for spreading. We relate the ideas to both the hydrodynamic viscous dissipation model and the molecular-kinetic theory of spreading. This suggests roughness and solid surface fraction modified Hoffman-de Gennes laws relating the edge speed to the dynamic and equilibrium contact angle. We also consider the spreading of small droplets and stripes of non-volatile liquids in the capillary regime and large droplets in the gravity regime. In the case of small non-volatile droplets spreading completely, a roughness modified Tanner's law giving the dependence of dynamic contact angle on time is presented. We review existing data for the spreading of small droplets of polydimethylsiloxane oil on surfaces decorated with micro-posts. On these surfaces, the initial droplet spreads with an approximately constant volume and the edge speed-dynamic contact angle relationship follows a power law [Formula: see text]. As the surface texture becomes stronger the exponent goes from p = 3 towards p = 1 in agreement with a Wenzel roughness driven spreading and a roughness modified Hoffman-de Gennes power law. Finally, we suggest that when a droplet spreads to a final partial wetting state on a rough surface, it approaches its Wenzel equilibrium contact angle in an exponential manner with a time constant dependent on roughness. PMID:21715886

McHale, Glen; Newton, Michael I; Shirtcliffe, Neil J

2009-10-29

246

Cortical Mapping of 3D Optical Topography in Infants.  

PubMed

Precise localisation of cortical activation in the early development of the infant brain remains unclear. It is challenging to co-register haemodynamic responses during functional activation in infants with the underlying anatomy of the brain. We used a multispectral imaging algorithm to reconstruct 3D optical topographic images of haemodynamic responses in an infant during voice processing. In this chapter, we present a method for co-registering 3D optical topography images reconstructed from functional activation data in infants onto anatomical brain images obtained from MRI structurals of the individual infants. PMID:23852529

Papademetriou, Maria D; Richards, John; Correia, Teresa; Blasi, Anna; Murphy, Declan G; Lloyd-Fox, Sarah; Johnson, Mark H; Elwell, Clare E

2013-01-01

247

The CMB Topography Beneath Cook Inlet And Alaskan Kenai Peninsula  

NASA Astrophysics Data System (ADS)

It has long been known that the PcP-to-P amplitude ratios demonstrate strong scatter in some regions. Rost and Revenaugh studied PcP amplitudes which sample the core-mantle boundary (CMB) beneath the Alaskan Kenai peninsula and the Cook inlet and found a ˜1° region on the CMB with very large PcP/P amplitude ratios. For some events, the ratios are several tens times larger than the theoretical ratios. After analyzing different possible mechanisms, they concluded the CMB topography is the major cause of the high amplitude ratios, but they did not give an quantitative topography model because of the lack of short period synthetic waveforms tools. We generate short period PcP synthetics using representation theorems and study the PcP phases theoretically for a core-mantle boundary (CMB) with single sinusoidal topography. After testing different combinations of the sinusoid wavelength L and amplitude H, we conclude that a dent in CMB with diameter of L=300km and height H=1˜2km best fits the observed data and can partly explain the high amplitude ratios. The PcP reflected from the CMB dip with L=300km and H=2km will be amplified by 2˜3 times which is smaller than the value the observed data needed. We primarily have three causes to determine L=300km and H=1˜2km. First, a dip with L=300km and H=1˜2km will focus the PcP significantly in a ˜1° region on the CMB which is consistent with the observed data. Certainly, the northern limit of the region is not clear, therefore more data are needed to constraint the northern limit and give a more reliable model. Second, there are not obvious travel time anomalies coupled with the high ratios in the observed PcP and our synthetic travel time anomalies are just about 0.4s too. Lastly, the strong similarities of P and PcP for some simple events excludes such large value of H. A dip with larger L and corresponding H surly produces stronger focusing effect, for example, a dip with L= 300km and H=3km will amplifies the PcP by 4˜5 times, but the waveform will be distorted seriously, contradictory to the similarity of P and PcP. So we speculate that the topography and other causes are combined to produce the high amplitude ratios together.

Wu, W.; Ni, S.

2009-05-01

248

Gravity Field, Topography, and Interior Structure of Amalthea  

NASA Astrophysics Data System (ADS)

A close Galileo flyby of Jupiter's inner moon Amalthea (JV) occurred on 5 November 2002. The final aimpoint was selected by the Galileo Radio Science Team on 5 July 2002. The closest approach distance for the selected aimpoint was 221 km from the center of mass, the latitude was - 45.23 Deg and the west longitude was 266.41 Deg (IAU/IAG/COSPAR cartographic coordinate system). In order to achieve an acceptable impact probability (0.15%), and yet fly close to Amalthea, the trajectory was selected from a class of trajectories running parallel to Amalthea's long axis. The Deep Space Network (DSN) had the capability to generate continuous coherent radio Doppler data during the flyby. Such data can be inverted to obtain information on Amalthea's gravity field. Amalthea is irregular and neither a triaxial ellipsoid nor an equilibrium body. It has a volume of about 2.4 x 106 km3, and its best-fit ellipsoid has dimensions 131x73x67 km. Its mass can be determined from the 2002 flyby, and in combination with the volume, a density can be obtained accurate to about 5%, where the error is dominated by the volume uncertainty. Similarly, gravity coefficients (Cnm Snm) can be detected up to fourth degree and order, and the second degree field (quadrupole) can be measured. Topography data are available from Voyager imaging and from images taken with Galileo's solid state imaging system at various times between February and June 1997. By combining the gravity and topography data, new information can be obtained on Amalthea's interior. For example if the gravity coefficients agree with those calculated from the topography, assuming constant density, we can conclude that Amalthea is homogeneous. On the other hand, if the gravity coefficients are smaller than predicted from topography, we can conclude that there is a concentration of mass toward Amalthea's center. We are presenting preliminary pre-publication results at the Fall meeting. This work was sponsored by the Galileo Project and was performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. G.S., P.C.T., and W.B.M. acknowledge support by grants from NASA under the Planetary Geology and Geophysics program. G.W. is a visiting PhD student at JPL, May 2002 - May 2003, and acknowledges support from the Austrian Ministry for Technology and a Zonta - Amelia Earhart fellowship.

Anderson, J. D.; Anabtawi, A.; Jacobson, R. A.; Johnson, T. V.; Lau, E. L.; Moore, W. B.; Schubert, G.; Taylor, A. H.; Thomas, P. C.; Weinwurm, G.

2002-12-01

249

The effect of Gonioscopy on keratometry and corneal surface topography  

PubMed Central

Background Biometric procedures such as keratometry performed shortly after contact procedures like gonioscopy and applanation tonometry could affect the validity of the measurement. This study was conducted to understand the short-term effect of gonioscopy on corneal curvature measurements and surface topography based Simulated Keratometry and whether this would alter the power of an intraocular lens implant calculated using post-gonioscopy measurements. We further compared the effect of the 2-mirror (Goldmann) and the 4-mirror (Sussman) Gonioscopes. Methods A prospective clinic-based self-controlled comparative study. 198 eyes of 99 patients, above 50 years of age, were studied. Exclusion criteria included documented dry eye, history of ocular surgery or trauma, diabetes mellitus and connective tissue disorders. Auto-Keratometry and corneal topography measurements were obtained at baseline and at three follow-up times – within the first 5 minutes, between the 10th-15th minute and between the 20th-25th minute after intervention. One eye was randomized for intervention with the 2-mirror gonioscope and the other underwent the 4-mirror after baseline measurements. t-tests were used to examine differences between interventions and between the measurement methods. The sample size was calculated using an estimate of clinically significant lens implant power changes based on the SRK-II formula. Results Clinically and statistically significant steepening was observed in the first 5 minutes and in the 10–15 minute interval using topography-based Sim K. These changes were not present with the Auto-Keratometer measurements. Although changes from baseline were noted between 20 and 25 minutes topographically, these were not clinically or statistically significant. There was no significant difference between the two types of gonioscopes. There was greater variability in the changes from baseline using the topography-based Sim K readings. Conclusion Reversible steepening of the central corneal surface is produced by the act of gonioscopy as measured by Sim K, whereas no significant differences were present with Auto-K measurements. The type of Gonioscope used does not appear to influence these results. If topographically derived Sim K is used to calculate the power of the intraocular lens implant, we recommend waiting a minimum of 20 minutes before measuring the corneal curvature after gonioscopy with either Goldmann or Sussman contact lenses.

George, Mathew K; Kuriakose, Thomas; DeBroff, Brian M; Emerson, John W

2006-01-01

250

Evolution of topography on comets. II. Icy craters and trenches  

SciTech Connect

The determination of the effects of topography on the sublimation rates of comets and other icy bodies is presently approached via a model of ice heating and sublimation from topographical features. The energy balance equation is solved for cylindrical trenches and spherical craters; the model encompasses shadowing, solar heating, the trapping of thermal radiation and sublimed gas molecules, and reflection of sunlight within the cavity. Generally, an enhancement is found in the net sublimation rate for trenches and craters farther from the sun than some critical distance which depends on the albedo. 15 refs.

Colwell, J.E.; Jakosky, B.M.; Sandor, B.J.; Stern, S.A. (Colorado Univ., Boulder (USA))

1990-05-01

251

Dynamic Topography during Flat Subduction: Subsidence or Uplift?  

NASA Astrophysics Data System (ADS)

Since the first studies on dynamic topography and basin evolution, low-dipping subduction has been related to intracontinental, long-wavelength and high-amplitude subsidence, whereas retreating to normal subduction systems to uplift. This was proposed to explain the Cretaceous-early Cenozoic topographic evolution of the western US. However, modern flat-slab and slab-retreating segments of South America do not record such a subsidence and uplift patterns. For example, the flat slab of Peru at ˜10°SL, related to the subduction of the Nazca Ridge, underlies an elevated promontory known as the Fitzcarrald Arch. The Argentine flat-slab at ˜31°SL associated to the subduction of the Juan Fernandez Ridge underlies a high-elevated intermontane system known as the Pampean broken foreland. Both upwarping features are younger than 7 Ma and contemporaneous with the arrival of flat subduction to these segments. In order to shed light into this controversy, we calculate dynamic topography along the Andean flat-slab segments using the Hager and O'Connell (1981) instantaneous flow formulation, an accurate reconstruction of the slab geometry along the central Andes and a density contrast between the flat slabs and the country mantle close to zero (???0) in order to simulate a buoyant oceanic lithosphere. We demonstrate that dynamic subsidence develops only at the leading edge of flat subduction, where the slabs plunge >30°, whereas the flatter slabs reproduce minor or no dynamic topography signals. These results agree with geological and geophysical proxies. Along the Argentine Plains, the <7 Ma maximum sedimentary accumulation coeval with the age of the flat subduction, plus the maximum modern relief account for a accumulated relief of ˜200 m, which might be considered as an "observed dynamic subsidence" signal (given that no tectonic activity has been recorded in this region since the Cretaceous to explain this surface topography). This gives a ˜0.03 mm/yr dynamic subsidence rate that are curiously similar to the exhumations estimated by low-temperature thermochronology along the Andean foreland (Dávila, 2011).

Davila, F. M.; Lithgow-Bertelloni, C. R.

2011-12-01

252

Surface topography induced by swift heavy ion impacts  

NASA Astrophysics Data System (ADS)

Classical molecular dynamics simulations have been carried out to investigate the development of surface topographies following irradiation by swift heavy ions. Two models were used: a thermal spike model in which atoms within a cylinder surrounding the path of the ion are given kinetic energy due to the electronic energy loss of the particle; and an electron stripping with recombination model. Both models give qualitatively similar results and show the formation of hillocks on the surface above the ion track and a less dense track core near to the surface.

Scott, Chris; Smith, Roger; Sickafus, K. E.

2011-07-01

253

Effect of surface topography and morphology on space charge packets in polyethylene  

NASA Astrophysics Data System (ADS)

Polyethylene (PE) is a major kind of internal insulating material. With great progresses of space charge measurement technologies in the last three decades, lots of researches are focused on space charge in PE. The heat pressing and annealing condition of polyethylene affect its morphology obviously. During the heat pressing, the surface of PE forms different surface topographies because of different substrate materials. Surface topography has great relation to the epitaxial crystallization layer and influences the space charge characteristic of PE dramatically. This paper studied the formation process of different surface topographies and their micrographic characters in low density polyethylene (LDPE). pulsed electro-acoustic (PEA) method was used to measure the space charge distribution of samples with different surface topographies and morphologies in LDPE. The effect of surface topography and morphology to space charge packet were studied. The surface topography has great influence on space charge packet polarity and morphology has influence on both movement speed rate and polarity of space charge packet.

Yuanxiang, Zhou; Yunshan, Wang; Ninghua, Wang; Qinghua, Sun

2009-08-01

254

Anomalous topography in the western Atlantic caused by edge-driven convection  

Microsoft Academic Search

The western Atlantic region contains a long-wavelength intraplate topography anomaly that is defined by the NE-SW trending Bermuda Rise and two adjacent topography lows. Using numerical experiments, we test the hypothesis that the anomalous topography may be the surface response to edge-driven convection. A primary edge-driven convection cell and secondary flow circulation develops at a modeled continent-ocean plate margin and

M. Hosein Shahnas; Russell N. Pysklywec

2004-01-01

255

Satellite based study of stratospheric gravity waves generated by topography  

NASA Astrophysics Data System (ADS)

Atmospheric Gravity Waves (AGWs) are oscillations manifested in atmospheric thermodynamic parameters like wind velocities, temperature, air density, pressure etc. at all altitudes in the atmosphere. The important sources of AGWs include wind flows over topography, latent heating of the atmosphere associated with convection, strong wind shears, adjustment of unbalanced flows in the vicinity of jet streams and frontal systems etc. Of these, mountain waves generated by airflow over topography are believed to be one of the dominant sources, particularly in the extra-tropics during winter. The study of mountain waves has been considered valuable by the scientific community for reasons such as, their impact on aviation, formation of rectilinear clouds etc. Moreover, mountain waves can easily transport momentum and energy vertically up through the middle atmosphere and the effect of which is essential to understand the general middle atmospheric circulation and chemistry. In the present study, we describe a mountain wave event observed in three dimensions using Atmospheric Infrared Sounder (AIRS) satellite measured atmospheric radiance and temperatures over the western Himalayan mountain region. As a supplement to the AIRS measurements, we have also used the temperature information obtained from Microwave Limb Sounder (MLS). The mountain wave event is also well represented in the high resolution Modern Era Retrospective-analysis for Research and Applications (MERRA) reanalysis data. It is found also close agreement between the observed and theoretical vertical wavelengths for a stationary gravity wave calculated reanalysis winds. Using three dimensional (3d) wave properties of the wave, we also estimated the wave momentum flux.

Kumar, K. N.; Thokuluwa, R.; Musali, K.

2011-12-01

256

Sample topography measurements by a novel image processing algorithm  

NASA Astrophysics Data System (ADS)

An exposure tool for lithography on non-flat samples is being developed. The pattern is directly written in a photoresist plated sample by moving the sample under a focused laser beam. During the writing process the topography of the surface is measured and a parametric model of the 3D surface is generated to allow for corrections of the exposure dose, the focus, and the direction of the light incident upon the sample. The system uses image processing techniques for estimating the distance of points on the surface to the objective. An illumination pattern consisting of four squares is projected on the surface of the sample. Images are taken with a high speed SCMOS camera. The topography of the sample is estimated from the measurements of the contrast around the projected patterns. To determine the contrast the k-means algorithm with k=2 is applied. The algorithm groups pixels into two clusters and the contrast is determined from average pixel values in high (u) and low intensity (v) clusters using (u-v)/Max; where max is the maximum pixel value detected in the image. Slope and focus quality are determined from the measured contrast values. The authors would like to thank NSF for financial support (grant: 0923506).

Aaron, Bryant; Tamir, Dan; Gatabi, Javad R.; Geerts, Wilhelmus; Pandey, R. K.

2012-03-01

257

Three Dimensional Surface Topography Using LCD Pattern Transfer Method  

NASA Astrophysics Data System (ADS)

Laser lithography on curved surfaces has recently been researched due to its applicability in production processes for devices that combine integrated optical, mechanical, magnetic, and/or electronic technologies. Several laser lithography methods have been reported for pattern transfer to convex and cylindrical surfaces, but there is not a general methodology for arbitrary 3D surface lithography. This project implements an optical method for laser lithography on arbitrary 3D surfaces. An illumination pattern generated by a transparent LCD is projected through an optical microscope on top of a 3D surface and recorded by a camera. The focus quality and the distortion of the observed image depend on the local topography of the sample. The effect of the local sample topography on the projected pattern is theoretically investigated using Zemax ray-tracing software. Analysis are made for amplitude and phase modulation LCDs with different resolutions and compared with preliminary experimental results. The authors acknowledge financial support from NSF through an MRI-grant (grant: 0923506).

Gatabi, Javad R.; Geerts, Wilhelmus; Aaron, Bryant; Tamir, Dan; Pandey, R. K.

2012-03-01

258

Modeling of fluidized ejecta emplacement over digital topography on Venus  

NASA Astrophysics Data System (ADS)

The FLOW computer model of McEwen and Malin (1989) modified for application to the study of Venus fluidized ejecta blankets (FEBs) demonstrates that relatively low viscosities, yield strengths, and initial velocities are required to duplicate the observed flow paths of the outflow materials. The model calculates the velocities and simulated flow paths of gravity flows over Magellan topography. The model is formulated to determine flow movements from initial conditions, gravitational acceleration, and resistance to motion as described by Coulomb, viscous, and turbulent resistance forces. Successful duplication of observed FEB flow paths has been achieved for the FEB craters Addams, Isabella, and Cochran. When used as a simple energy-line model, the model requires low coefficients of friction to extend FEBs to near their observed termini in the synthetic aperture radar (SAR) imagery, although the resulting straight flow lines do not follow the observed flow paths well. For Bingham flow, the model requires low values of viscosity and yield strength which are more similar to pyroclastic or debris flows than basaltic lavas. Flows of 100-m depth require 1 to 2 orders of magnitude higher values of both viscosity and yield strength than 10-m-deep flows. The complicated nature of the flow lines for the low velocity model suggests that FEBs were probably emplaced under variably laminar and turbulent flow conditions, where underlying topography influenced both the direction and energy of flow materials.

Johnson, Jeffrey R.; Gaddis, Lisa

259

Photoswitchable hydrogel surface topographies by polymerisation-induced diffusion.  

PubMed

Herein, we describe the preparation of patterned photoresponsive hydrogels by using a facile method. This polymer-network hydrogel coating consists of N-isopropylacrylamide (NIPAAM), cross-linking agent tripropylene glycol diacrylate (TPGDA), and a new photochromic spiropyran monoacrylate. In a pre-study, a linear NIPAAM copolymer (without TPGDA) that contained the spiropyran dye was synthesised, which showed relatively fast photoswitching behaviour. Subsequently, the photopolymerisation of a similar monomer mixture that included TPGDA afforded freestanding hydrogel polymer networks. The light-induced isomerisation of protonated merocyanine into neutral spiropyran under slightly acidic conditions resulted in macroscopic changes in the hydrophilicity of the entire polymer film, that is, shrinkage of the hydrogel. The degree of shrinkage could be controlled by changing the chemical composition of the acrylate mixture. After these pre-studies, a hydrogel film with spatially modulated cross-link density was fabricated through polymerisation-induced diffusion, by using a patterned photomask. The resulting smooth patterned hydrogel coating swelled in slightly acidic media and the swelling was higher in the regions with lower cross-linking densities, thus yielding a corrugated surface. Upon exposure to visible light, the surface topography flattened again, thus showing that a hydrogel coating could be created, the topography of which could be controlled by light irradiation. PMID:23821576

Stumpel, Jelle E; Liu, Danqing; Broer, Dirk J; Schenning, Albertus P H J

2013-07-02

260

The contribution of eddies to striations in absolute dynamic topography  

NASA Astrophysics Data System (ADS)

AbstractDistinct 4 year averages of absolute dynamic <span class="hlt">topography</span> reveal striations in all ocean basins during 1993-2008. Striations are alternating mesoscale jet-like structures observed in time-averaged zonal geostrophic velocity, u>¯. They are characterized by speeds O(1 cm s-1) and are nominally separated by 200 km in the meridional direction. Similar patterns have been observed in sea level anomaly, mean dynamic <span class="hlt">topography</span>, and Argo float measurements. Use of a tracked-eddy database in concert with a contour identification and eddy removal algorithm demonstrates that eddies are a dominant source of striations in u>¯ in the South Pacific (20°S-50°S, 200°E-280°E). Eddies with lifetimes ? 4 weeks account for 46-57% of the variance in u>¯ and correlation coefficients between total and eddy-only u>¯ are 0.90-0.93. Attention is given to the ability of the algorithm to correctly identify eddies and suggests that a more appropriate bound on the variance due to eddies is ˜ 30-70%. This permits the existence of latent zonal jets and/or ?-plumes. Additional findings of the study include (1) a large number of eddies having a broad range of amplitudes and scales contribute most to the eddy-induced patterns and (2) the standard deviation of u>¯ does not decay inversely with averaging period as proposed by a model of random eddies.</p> <div class="credits"> <p class="dwt_author">Buckingham, C. E.; Cornillon, P. C.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_12");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' 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showDiv("page_12");' href="#">12</a> <a onClick='return showDiv("page_13");' href="#">13</a> <a style="font-weight: bold;">14</a> <a onClick='return showDiv("page_15");' href="#">15</a> <a onClick='return showDiv("page_16");' href="#">16</a> <a onClick='return showDiv("page_17");' href="#">17</a> <a onClick='return showDiv("page_18");' href="#">18</a> <a onClick='return showDiv("page_19");' href="#">19</a> <a onClick='return showDiv("page_20");' href="#">20</a> <a onClick='return showDiv("page_21");' href="#">21</a> <a onClick='return showDiv("page_22");' href="#">22</a> <a onClick='return showDiv("page_23");' href="#">23</a> <a onClick='return showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_15");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">261</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/22307028"> <span id="translatedtitle">Osteoclast resorption of thermal spray hydoxyapatite coatings is influenced by surface <span class="hlt">topography</span>.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Coating characteristics such as composition, crystallite features and <span class="hlt">topography</span> collectively impact the cell response. The influence from splats has not yet been assessed for hydroxyapatite (HAp) thermal spray coatings. The objective of this work is to (a) survey the <span class="hlt">topography</span> on commercial implants, (b) ascertain <span class="hlt">topography</span> formation from single splats, and (c) determine the osteoclast resorption pattern on a topographically refined coating compared to dentine. Coatings on dental implants, an orthopedic screw, a femoral stem and a knee implant were studied for reference. The effects of substrate pre-heat, roughness, spray distance and particle size on the coating roughness and <span class="hlt">topography</span> were studied. Human-derived osteoclasts were placed on a coating with refined <span class="hlt">topography</span> and compared to dentine, a polished coating and polished sintered HAp. A pre-heat of at least 200°C on titanium was required to form rounded splats. The greatest influence on coating roughness and <span class="hlt">topography</span> arose from particle size. A 2-fold increase in the mean particle size from 30 to 72 ?m produced a significant difference (P<0.001) in roughness from 4.8 and 9.7 ?m. A model is shown to illustrate <span class="hlt">topography</span> formation, nanostructure evolution on single splats, and the <span class="hlt">topography</span> as seen in commercial implants. Osteoclasts showed a clear preference for activity on coatings with refined <span class="hlt">topography</span>. A one-way ANOVA test revealed a significantly greater pit depth (P=0.022) for dentine (14 ?m) compared to the as-sprayed and polished coating (5 ?m). Coatings with <span class="hlt">topography</span> display a similar number of resorption pits with dentine, but a 10-fold greater number than polished coatings, emphasizing the importance of flattened droplet <span class="hlt">topography</span> on implant surfaces. PMID:22307028</p> <div class="credits"> <p class="dwt_author">Gross, Karlis A; Muller, Dirk; Lucas, Helen; Haynes, David R</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-01-25</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">262</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2011AGUFMDI23A2075F"> <span id="translatedtitle">Longevity and rheology of cratons: key constraints from surface <span class="hlt">topography</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Archean cratons are stable remnants of Earth's early continental lithosphere. Their structure, composition and survival over geological time spans make them ones of the most unique and enigmatic features of the Earth's surface. It has become evident from both geophysical and petrological studies that cratons exhibit deep lithospheric roots, which remained stable ever since their formation in the early Archean. The question of how some of the cratons survived destruction over timescales of billions of years remains a subject of vigorous debate. In order to understand what controls the long-term stability of the cratons, we investigated the impact of the thermo-rheological structure of the lithosphere on the evolution of both surface <span class="hlt">topography</span> and cratonic roots using fully coupled thermo-mechanical numerical models (600*3000 km, free upper surface <span class="hlt">topography</span>, layered lithospheric structure). Our model has a particular focus on the Canadian Shield, where considerable structural and thermal data are available from both geological and geophysical studies. In particular, we compare the implications of the "Cratonic" "Jelly-Sandwich" rheology (JS; strong dry olivine mantle, strong crust, cold geotherm with Moho temperature of 400°C, thermal lithosphere thickness of 250 km) with those of the "Crème Brûlée" rheology (CB; strong crust, weak wet olivine mantle, Moho temperature of 600°C, thermal lithosphere thickness of 150 km) (Figure 1). Our experiments show that, in the case of a laterally homogeneous lithosphere and in the absence of tectonic shortening or extension (blocked borders), both JS and CB rheologies may account for the stability of the shield and its surface <span class="hlt">topography</span>. In this case continental lithosphere remains stable over large time spans, even for the weakest wet olivine mantle (but for "cold" thermal gradients). Nevertheless, for a laterally heterogeneous crust, as is the case for the Canadian Shield and most cratons, dry olivine mantle JS rheology provides a far more stable lithosphere, with surface undulations < 1000m over 0.3 Gy time spans, compared to the unlikely ~8000m surface undulations produced by CB rheology. In addition, the CB lithosphere gets quickly unstable when minor tectonic compression is applied, generating unrealistic short-wavelength surface undulations. These results demonstrate the need to consider buried loads and tectonic forces whenever constraining long-term rheological properties of the lithosphere, and suggest that the "Jelly-Sandwich" rheology so far better accounts for natural observations.</p> <div class="credits"> <p class="dwt_author">Francois, T.; Burov, E. B.; Meyer, B.; Agard, P.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">263</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/22722085"> <span id="translatedtitle">Eye shape and retinal <span class="hlt">topography</span> in owls (Aves: Strigiformes).</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">The eyes of vertebrates show adaptations to the visual environments in which they evolve. For example, eye shape is associated with activity pattern, while retinal <span class="hlt">topography</span> is related to the symmetry or 'openness' of the habitat of a species. Although these relationships are well documented in many vertebrates including birds, the extent to which they hold true for species within the same avian order is not well understood. Owls (Strigiformes) represent an ideal group for the study of interspecific variation in the avian visual system because they are one of very few avian orders to contain species that vary in both activity pattern and habitat preference. Here, we examined interspecific variation in eye shape and retinal <span class="hlt">topography</span> in nine species of owl. Eye shape (the ratio of corneal diameter to eye axial length) differed among species, with nocturnal species having relatively larger corneal diameters than diurnal species. All the owl species have an area of high retinal ganglion cell (RGC) density in the temporal retina and a visual streak of increased cell density extending across the central retina from temporal to nasal. However, the organization and degree of elongation of the visual streak varied considerably among species and this variation was quantified using H:V ratios. Species that live in open habitats and/or that are more diurnally active have well-defined, elongated visual streaks and high H:V ratios (3.88-2.33). In contrast, most nocturnal and/or forest-dwelling owls have a poorly defined visual streak, a more radially symmetrical arrangement of RGCs and lower H:V ratios (1.77-1.27). The results of a hierarchical cluster analysis indicate that the apparent interspecific variation is associated with activity pattern and habitat as opposed to the phylogenetic relationships among species. In seven species, the presence of a fovea was confirmed and it is suggested that all strigid owls may possess a fovea, whereas the tytonid barn owl (Tyto alba) does not. A size-frequency analysis of cell soma area indicates that a number of different RGC classes are represented in owls, including a population of large RGCs (cell soma area >150 µm(2)) that resemble the giant RGCs reported in other vertebrates. In conclusion, eye shape and retinal <span class="hlt">topography</span> in owls vary among species and this variation is associated with different activity patterns and habitat preferences, thereby supporting similar observations in other vertebrates. PMID:22722085</p> <div class="credits"> <p class="dwt_author">Lisney, Thomas J; Iwaniuk, Andrew N; Bandet, Mischa V; Wylie, Douglas R</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-06-18</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">264</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2005AGUFM.H52A..05M"> <span id="translatedtitle">Continuum Statistics of the Bed <span class="hlt">Topography</span> in a Sandy River</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Temporal and spatial variabilities in the bed geometry of sandy rivers contain information about processes of sediment transport that has not been fully appreciated. This is primarily due to a disparity between the dynamic nature of the sediment-fluid interface and the relatively static methods of surveying bed elevation, e.g. single profiles or point measurements. High resolution topographic data is paramount to understanding the dynamic behavior of sandy beds. We present and analyze a data set collected on a 2cm x 2cm grid at 1 minute intervals and with a vertical precision of ~1mm. This was accomplished by using Lambert-Beer's Law for attenuation of light to transform low-altitude aerial photographs into digital elevation models. Forty successive models were generated for a 20 m by 30 m section of channel bottom of the N. Loup River, Nebraska. To calculate the average, whole bed translation rate, or celerity, cross-correlations between a reference bed <span class="hlt">topography</span> and its proceeding configurations were determined. Time differences between models were related to the shift lengths that produced correlation maxima for each model pair. The result is a celerity of ~3.8cm/s with a correlation coefficient of 0.992. Bed <span class="hlt">topography</span> also deforms while it translates, and this can be seen as a secular decrease of correlation maxima. The form of this decrease in correlation is exponential, and from it an interface half-life is defined. In this case, the bed had become extensively reorganized within ~40 minutes, the time necessary to translate the bed one wavelength of the dominant roughness element. Although the bed is continuously deforming, its roughness is statistically stationary. Essentially, a mean roughness is maintained as the bed creates new realizations of itself. The dynamic nature of the whole bed and similarly transient behavior of individual elements suggests the utility of a holistic approach to studying the feedback between bed <span class="hlt">topography</span>, fluid flow, and sediment transport. Furthermore, it raises questions about the usefulness of detailed analysis of flow and transport over individual forms.</p> <div class="credits"> <p class="dwt_author">McElroy, B.; Jerolmack, D.; Mohrig, D.</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">265</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=DE86009050"> <span id="translatedtitle">Research Consortium for X-Ray <span class="hlt">Topography</span> on Line X-19 at NSLS.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">Twelve short reports of NSLS work are included; energy selective white beam synchrotron <span class="hlt">topography</span> of GaAs crystals, in-situ x-ray synchrotron <span class="hlt">topography</span> of slip initiation in Mo monocrystals, lattice rotations associated with crack-tip structures in Mo a...</p> <div class="credits"> <p class="dwt_author">J. C. Bilello</p> <p class="dwt_publisher"></p> <p class="publishDate">1985-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">266</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.toyota-ti.ac.jp/Lab/Kikai/5k60/furutani/paper/data/mtm1113.pdf"> <span id="translatedtitle">In-process measurement of <span class="hlt">topography</span> change of grinding wheel by using hydrodynamic pressure</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">This paper deals with an in-process measurement method for <span class="hlt">topography</span> change of a grinding wheel, which can apply to wet grinding. A pressure sensor is set beside a grinding wheel with a small gap. When grinding fluid is dragged into the gap, hydrodynamic pressure, which corresponds to the gap length and the <span class="hlt">topography</span>, can be measured. This method is applied</p> <div class="credits"> <p class="dwt_author">Katsushi Furutani; Noriyuki Ohguro; Nguyen Trong Hieu; Takashi Nakamura</p> <p class="dwt_publisher"></p> <p class="publishDate">2002-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">267</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=N19970021180"> <span id="translatedtitle">Inversion of Gravity and <span class="hlt">Topography</span> for Mantle and Crustal Structure on Mars.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">Analysis of the gravity and <span class="hlt">topography</span> of Mars presently provides our primary quantitative constraints on the internal structure of Mars. We present an inversion of the long-wavelength (harmonic degree less than or equal to 10) gravity and <span class="hlt">topography</span> of M...</p> <div class="credits"> <p class="dwt_author">W. S. Kiefer B. G. Bills R. S. Nerem</p> <p class="dwt_publisher"></p> <p class="publishDate">1996-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">268</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/28989734"> <span id="translatedtitle">A role for surface <span class="hlt">topography</span> in creating and maintaining bone at titanium endosseous implants</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Statement of problem. A variety of claims are made regarding the effects of surface <span class="hlt">topography</span> on implant osseointegration. Many in vivo and in vitro experimental observations have key limitations in their interpretations. Purpose. This review considers the major claims made concerning the effects of commercially pure (cp) titanium implant surface <span class="hlt">topography</span> on osseointegration. Important findings of consensus are highlighted, and</p> <div class="credits"> <p class="dwt_author">Lyndon F. Cooper</p> <p class="dwt_publisher"></p> <p class="publishDate">2000-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">269</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/55620819"> <span id="translatedtitle">The Relationship of the MOLA <span class="hlt">Topography</span> of Mars to the Mean Atmospheric Pressure</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The MOLA <span class="hlt">topography</span> of Mars is based on a new mean radius of the planet and new equipotential surface for the areoid. The mean atmospheric pressure surface of 6.1mbars that has been used in the past as a reference level for <span class="hlt">topography</span> does not apply to the zero level of MOLA elevations. The MOLA mean radius of the planet is</p> <div class="credits"> <p class="dwt_author">D. E. Smith; M. T. Zuber</p> <p class="dwt_publisher"></p> <p class="publishDate">1999-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">270</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.gfdl.noaa.gov/~aja/papers/adcroft_et_al_MWR_1997.pdf"> <span id="translatedtitle">Representation of <span class="hlt">Topography</span> by Shaved Cells in a Height Coordinate Ocean Model</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Height coordinate ocean models commonly represent <span class="hlt">topography</span> as a ''staircase'' of discontinuous steps that are fitted to the model grid. Here the ramifications of an alternative approach are studied in which ''shaved cells'' are used to represent irregular <span class="hlt">topography</span>. The problem is formulated using the finite-volume method and care is taken to ensure that the discrete forms have appropriate conservation</p> <div class="credits"> <p class="dwt_author">Alistair Adcroft; Chris Hill; John Marshall</p> <p class="dwt_publisher"></p> <p class="publishDate">1997-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">271</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/42011320"> <span id="translatedtitle">Three-dimensional distribution and evolution of permafrost temperatures in idealized high-mountain <span class="hlt">topography</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Permafrost degradation is regarded as a crucial factor influencing the stability of steep rockwalls in alpine areas. Discernment of zones of fast temperature changes requires knowledge about the temperature distribution and evolution at and below the surface of steep rock. In complex high-mountain <span class="hlt">topography</span>, strong lateral heat fluxes result from <span class="hlt">topography</span> and variable surface temperatures and profoundly influence the subsurface</p> <div class="credits"> <p class="dwt_author">Jeannette Noetzli; Stephan Gruber; Thomas Kohl; Nadine Salzmann; Wilfried Haeberli</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">272</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/30161279"> <span id="translatedtitle">Transcranial magnetic-stimulation mapping of the cortical <span class="hlt">topography</span> of the human masseter muscle</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The cortical <span class="hlt">topography</span> of several limb and trunk muscles has been disclosed using transcranial magnetic stimulation, but the corticomotor representation of the human jaw muscles has not yet been described. An experimental paradigm incorporating transcranial magnetic stimulation of verified sites on the scalp was used (a) to determine the cortical <span class="hlt">topography</span> of the human masseter muscle and (b) to assess</p> <div class="credits"> <p class="dwt_author">Anne S. McMillan; Catherine Watson; David Walshaw</p> <p class="dwt_publisher"></p> <p class="publishDate">1998-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">273</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.geo.umass.edu/structure/mario/pdfs/Del-Castello_et_al_2004.pdf"> <span id="translatedtitle">Effect of unbalanced <span class="hlt">topography</span> and overloading on Coulomb wedge kinematics: Insights from sandbox modeling</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">(1) This study addresses the effect of variable unbalanced <span class="hlt">topography</span> and overload on the kinematics of a fold and thrust belt developed within a collisional belt that underwent a subduction polarity reversal event. This was done by physical modeling of doubly vergent Coulomb wedges, using sand as an analogue material. During the experimental procedure a preexisting <span class="hlt">topography</span> was generated by</p> <div class="credits"> <p class="dwt_author">Gian Andrea Pini; Kenneth R. McClay</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">274</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/48899353"> <span id="translatedtitle">Effect of unbalanced <span class="hlt">topography</span> and overloading on Coulomb wedge kinematics: Insights from sandbox modeling</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">This study addresses the effect of variable unbalanced <span class="hlt">topography</span> and overload on the kinematics of a fold and thrust belt developed within a collisional belt that underwent a subduction polarity reversal event. This was done by physical modeling of doubly vergent Coulomb wedges, using sand as an analogue material. During the experimental procedure a preexisting <span class="hlt">topography</span> was generated by a</p> <div class="credits"> <p class="dwt_author">Mario Del Castello; Gian Andrea Pini; Kenneth R. McClay</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">275</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.agu.org/journals/je/v101/iE04/95JE03699/95JE03699.pdf"> <span id="translatedtitle">An inversion of gravity and <span class="hlt">topography</span> for mantle and crustal structure on Mars</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Analysis of the gravity and <span class="hlt">topography</span> of Mars presently provides our primary quantitative constraints on the internal structure of Mars. We present an inversion of the long- wavelength (harmonic degree _< 10) gravity and <span class="hlt">topography</span> of Mars for lateral variations of mantle temperature and crustal thickness. Our formulation incorporates both viscous mantle flow (which most prior studies have neglected) and</p> <div class="credits"> <p class="dwt_author">Walter S. Kiefer; Bruce G. Bills; R. Steven Nerem</p> <p class="dwt_publisher"></p> <p class="publishDate">1996-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">276</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3775085"> <span id="translatedtitle"><span class="hlt">Topography</span>-guided custom ablation treatment for treatment of keratoconus</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Keratoconus is a progressive ectatic disorder of the cornea which often presents with fluctuating refraction and high irregular astigmatism. Correcting the vision of these patients is often a challenge because glasses are unable to correct the irregular astigmatism and regular contact lenses may not fit them very well. <span class="hlt">Topography</span>-guided custom ablation treatment (T-CAT) is a procedure of limited ablation of the cornea using excimer laser with the aim of regularizing the cornea, improving the quality of vision and possibly contact lens fit. The aim of the procedure is not to give a complete refractive correction. It has been tried with a lot of success by various groups of refractive surgeons around the world but a meticulous and methodical planning of the procedure is essential to ensure optimum results. In this paper, we attempt to elucidate the planning for a T-CAT procedure for various types of cones and asphericities.</p> <div class="credits"> <p class="dwt_author">Shetty, Rohit; D'Souza, Sharon; Srivastava, Samaresh; Ashwini, R</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">277</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/21057071"> <span id="translatedtitle">Different Approach to the Aluminium Oxide <span class="hlt">Topography</span> Characterisation</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Different surface topographic techniques are being widely used for quantitative measurements of typical industrial aluminium oxide surfaces. In this research, specific surface of aluminium oxide layer on the offset printing plate has been investigated by using measuring methods which have previously not been used for characterisation of such surfaces. By using two contact instruments and non-contact laser profilometer (LPM) 2D and 3D roughness parameters have been defined. SEM micrographs of the samples were made. Results have shown that aluminium oxide surfaces with the same average roughness value (Ra) and mean roughness depth (Rz) typically used in the printing plate surface characterisation, have dramatically different surface <span class="hlt">topographies</span>. According to the type of instrument specific roughness parameters should be used for defining the printing plate surfaces. New surface roughness parameters were defined in order to insure detailed characterisation of the printing plates in graphic reproduction process.</p> <div class="credits"> <p class="dwt_author">Poljacek, Sanja Mahovic; Gojo, Miroslav [Faculty of Graphic Arts, University of Zagreb, Getaldiceva 2, 10000 Zagreb (Croatia); Raos, Pero; Stoic, Antun [Mechanical Engineering Faculty, J.J. Strossmayer University of Osijek, Trg Ivane Brlic Mazuranic 2, 35000 Slavonski Brod (Croatia)</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-04-07</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">278</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/20053078"> <span id="translatedtitle">Experience-dependent changes in the <span class="hlt">topography</span> of visual crowding.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">The present work examined discrimination accuracy for targets that were presented either alone in the visual field (clean displays) or embedded within a dense array of letter distractors (crowded displays). The strength of visual crowding varied strongly across the four quadrants of the visual field. Furthermore, this spatial bias in crowding was strongly influenced by the observers' prior experience with specific distractor stimuli. Observers who were monolingual readers of English experienced amplified crowding in the upper-left quadrant, while subjects with primary reading skills in Korean, Chinese, or Japanese tended towards worse target discrimination in the lower visual field. This interaction with language experience was eliminated when non-alphanumeric stimuli were employed as distractors, suggesting that prior reading experience induced a stimulus-specific change in the <span class="hlt">topography</span> of visual crowding from English letters. PMID:20053078</p> <div class="credits"> <p class="dwt_author">Williamson, Kristin; Scolari, Miranda; Jeong, Sukeun; Kim, Min-Shik; Awh, Edward</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-10-14</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">279</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/1051628"> <span id="translatedtitle">Characterization of Mo/Si multilayer growth on stepped <span class="hlt">topographies</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Mo/Si multilayer mirrors with nanoscale bilayer thicknesses have been deposited on stepped substrate <span class="hlt">topographies</span>, using various deposition angles. The multilayer morphology at the stepedge region was studied by cross section transmission electron microscopy. A transition from a continuous- to columnar layer morphology is observed near the step-edge, as a function of the local angle of incidence of the deposition flux. Taking into account the corresponding kinetics and anisotropy in layer growth, a continuum model has been developed to give a detailed description of the height profiles of the individual continuous layers. Complementary optical characterization of the multilayer system using a microscope operating in the extreme ultraviolet wavelength range, revealed that the influence of the step-edge on the planar multilayer structure is restricted to a region within 300 nm from the step-edge.</p> <div class="credits"> <p class="dwt_author">Boogaard, A. J. R. vcan den; Louis, E.; Zoethout, E.; Goldberg, K. A.; Bijkerk, F.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-08-31</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">280</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1999Geo....27..563G"> <span id="translatedtitle">Plate detachment, asthenosphere upwelling, and <span class="hlt">topography</span> across subduction zones</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">This study analyzes the <span class="hlt">topography</span> across subduction zones, considering the separate contributions of the crust and the mantle lithosphere to the observed surface elevation. We have found a transition from a region where the overriding plate is coupled to the descending slab and pulled down along with it to a region where the overriding plate floats freely on the asthenosphere. When the subducting slab retreats oceanward rapidly this transition is abrupt, and the edge of the overriding plate is uplifted. We propose that at some point during rapid slab rollback the overriding plate detaches and rebounds like a boat released from its keel. This event is associated with suction of asthenospheric material into the gap that is opened between the plates up to the base of the crust. As a result, the forearc uplifts, and magmatism in the arc increases.</p> <div class="credits"> <p class="dwt_author">Gvirtzman, Zohar; Nur, Amos</p> <p class="dwt_publisher"></p> <p class="publishDate">1999-06-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_13");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a 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title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">281</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/1048123"> <span id="translatedtitle">SRF Cavity Surface <span class="hlt">Topography</span> Characterization Using Replica Techniques</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">To better understand the roll of <span class="hlt">topography</span> on SRF cavity performance, we seek to obtain detailed topographic information from the curved practical cavity surfaces. Replicas taken from a cavity interior surface provide internal surface molds for fine Atomic Force Microscopy (AFM) and stylus profilometry. In this study, we confirm the replica resolution both on surface local defects such as grain boundary and etching pits and compare the surface uniform roughness with the aid of Power Spectral Density (PSD) where we can statistically obtain roughness parameters at different scales. A series of sampling locations are at the same magnetic field chosen at the same latitude on a single cell cavity to confirm the uniformity. Another series of sampling locations at different magnetic field amplitudes are chosen for this replica on the same cavity for later power loss calculation. We also show that application of the replica followed by rinsing does not adversely affect the cavity performance.</p> <div class="credits"> <p class="dwt_author">C. Xu, M.J. Kelley, C.E. Reece</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-07-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">282</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2004SPIE.5249..353V"> <span id="translatedtitle"><span class="hlt">Topography</span> of the merit function landscape in optical system design</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We have shown recently that, when certain quite general conditions are satisfied, the set of local minima in the optical merit function space forms a network where they are all connected through optimization paths generated from saddle points having a Morse index of 1. A new global optimization method, that makes use of this linking network to systematically detect all minima, is presented. The central component of this new method, the algorithm for saddle point detection, is described in detail and we show that the initialization of this algorithm has a significant impact on the performance. For a simple global optimization search (Cooke triplet) several representation forms of the network of the corresponding set of local minima are presented. These representations, which can be visualized in two dimensions, are independent of the dimensionality of the design space so that they can provide insight into the <span class="hlt">topography</span> of merit function landscapes of arbitrary dimensionality.</p> <div class="credits"> <p class="dwt_author">van Driel, Eco; Bociort, Florian; Serebriakov, Alexander</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-02-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">283</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2011SPIE.8286E...2Y"> <span id="translatedtitle">Development of the airborne lidar surface <span class="hlt">topography</span> simulator</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In 2008 we began a three-year NASA Earth Science Technology Office (ESTO) funded Instrument Incubator Program (IIP) focused on technology development for the Lidar Surface <span class="hlt">Topography</span> (LIST) mission. The LIST mission is one of the Earth Science Decadal Survey missions recommended to NASA by the National Research Council (NRC). Our IIP objective is to demonstrate the measurement approach and key technologies needed for a highly efficient swath mapping lidar to meet the goals of the LIST mission. To demonstrate the concept we are developing the Airborne LIST Simulator (A-LISTS) instrument. In this paper we summarize the A-LISTS instrument characteristics and the approaches we are using to advance lidar capabilities and reduce risks for LIST.</p> <div class="credits"> <p class="dwt_author">Yu, Anthony W.; Harding, David J.; Krainak, Michael A.; Abshire, James B.; Sun, Xiaoli; Cavanaugh, John; Valett, Susan; Ramos-Izquiedro, Luis; Winkert, Tom; Plants, Michael; Kirchner, Cynthia; Kamamia, Brian; Hasselbrack, William; Filemyr, Timothy</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-06-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">284</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2010AGUFM.C41A0513M"> <span id="translatedtitle">High-precision Ice Surface <span class="hlt">Topography</span> Mapping Using Radar Interferometry</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In May 2009 a new radar technique for mapping ice surface <span class="hlt">topography</span> was demonstrated in a Greenland campaign as part of the NASA International Polar Year activities. This was achieved with the airborne Glacier and Ice Surface <span class="hlt">Topography</span> Interferometer (GLISTIN-A): a 35.6 GHz single-pass interferometer. Although the technique of using radar interferometry for mapping terrain has been demonstrated before, this is the first such application at millimeter-wave frequencies. Instrument performance indicates swath widths over the ice between 5-7km, with height precisions ranging from 30cm-3m at a posting of 3m x 3m. However, for this application the electromagnetic wave will penetrate an unknown amount into the snow cover thus producing an effective bias that must be calibrated. To evaluate this, GLISTIN-A flew a coordinated collection with the NASA Wallops Airborne Topographic Mapper (ATM) on a transect from Greenland’s Summit to its West coast. Two field calibration sites were established at Colorado Institute for Research in Environmental Science’s Swiss Camp and the National Science Foundation’s Summit station. Additional collections entailed flying a mosaic over Jakobshavn glacier which was repeated after 6 days to reveal surface dynamics. Through detailed calibration and inter-sensor comparisons we were able to observe penetration biases and compare them with theoretical expectations. We also demonstrated GLISTIN-A’s capability to measure the <span class="hlt">topography</span> of large glacier systems in a seamless fashion and accurately measuring volume changes with a high level of spatial detail. In particular, repeating the airborne campaigns to observe elevation changes over time will allow very accurate volume change measurements. Not only is this very important for mass balance studies to have a precise mass-loss estimate, but the spatial pattern can reveal ice dynamics effects and surface mass balance effects. In this manner a high resolution, high-precision topographic mapping capability is an ideal complement to the ICESat, ICESat II and Cryosat altimeters. Interpolating between the high-accuracy elevation profiles from altimeters such as the ATM or ICESat II with the high-resolution GLISTIN-A swath will enable detailed ice-surface <span class="hlt">topography</span> maps and extended spatial coverage. The result is the potential for higher fidelity mass-balance estimates and improved observational coverage. Upgrades are currently underway to improve the performance and portability of GLISTIN-A such that, onboard a long-range aircraft this radar can map Greenland’s significant glaciers in a few days. The upgraded GLISTIN-A will be compatible with GlobalHawk installation making, Antarctica basin and coastal mapping feasible. GLISTIN will make more topographic products available to glaciologists, initially through dedicated airborne campaigns or ultimately, perhaps, as a satellite mission.</p> <div class="credits"> <p class="dwt_author">Moller, D.; Hensley, S.; Michel, T.; Rignot, E. J.; Simard, M.; Krabill, W. B.; Sonntag, J. G.</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">285</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/23925335"> <span id="translatedtitle"><span class="hlt">Topography</span>-guided custom ablation treatment for treatment of keratoconus.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Keratoconus is a progressive ectatic disorder of the cornea which often presents with fluctuating refraction and high irregular astigmatism. Correcting the vision of these patients is often a challenge because glasses are unable to correct the irregular astigmatism and regular contact lenses may not fit them very well. <span class="hlt">Topography</span>-guided custom ablation treatment (T-CAT) is a procedure of limited ablation of the cornea using excimer laser with the aim of regularizing the cornea, improving the quality of vision and possibly contact lens fit. The aim of the procedure is not to give a complete refractive correction. It has been tried with a lot of success by various groups of refractive surgeons around the world but a meticulous and methodical planning of the procedure is essential to ensure optimum results. In this paper, we attempt to elucidate the planning for a T-CAT procedure for various types of cones and asphericities. PMID:23925335</p> <div class="credits"> <p class="dwt_author">Shetty, Rohit; D'Souza, Sharon; Srivastava, Samaresh; Ashwini, R</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-08-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">286</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013EGUGA..1510271N"> <span id="translatedtitle">Assimilation of dynamic <span class="hlt">topography</span> in a global ocean model</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Absolute dynamic <span class="hlt">topography</span>, i.e. the difference between time dependent multi-mission altimetric sea surface height and one of the most recent GOCE and GRACE based geoids, is assimilated in a global ocean general circulation model. To this end we apply an ensemble based Kalman technique, the "Error Subspace Transform Kalman Filter" (ESTKF). Here we present an update of our work. First of all the geoid is improved over previous versions. The ocean model now includes better dynamics and full sea-ice ocean interactions and more realistic surface forcing. Finally the assimilation method is augmented by a fixed lag smoother technique. This smoother allows to significantly improve the model performance, most strikingly in the first adjustment phase.</p> <div class="credits"> <p class="dwt_author">Nerger, Lars; Albertella, Alberta; Bosch, Wolfgang; Janjic, Tijana; Schnur, Reiner; Savcenko, Roman; Scheinert, Mirko; Schröter, Jens; Schwabe, Joachim</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-04-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">287</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2741225"> <span id="translatedtitle">Enhanced surface hydrophobicity by coupling of surface polarity and <span class="hlt">topography</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">We use atomistic computer simulation to explore the relationship between mesoscopic (liquid drop contact angle) and microscopic (surface atomic polarity) characteristics for water in contact with a model solid surface based on the structure of silica. We vary both the magnitude and direction of the solid surface polarity at the atomic scale and characterize the response of an aqueous interface in terms of the solvent molecular organization and contact angle. We show that when the <span class="hlt">topography</span> and polarity of the surface act in concert with the asymmetric charge distribution of water, the hydrophobicity varies substantially and, further, can be maximal for a surface with significant polarity. The results suggest that patterning of a surface on several length scales, from atomic to ?m lengths, can make important independent contributions to macroscopic hydrophobicity.</p> <div class="credits"> <p class="dwt_author">Giovambattista, Nicolas; Debenedetti, Pablo G.; Rossky, Peter J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">288</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/21812052"> <span id="translatedtitle">Simultaneous <span class="hlt">topography</span> and recognition imaging on endothelial cells.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Determining the landscape of specific binding sites on biological samples with high spatial accuracy (in the order of several nanometres) is an important task in many fields of biological science. During the past five years, dynamic recognition imaging (e.g. simultaneous <span class="hlt">topography</span> and recognition (TREC) imaging) has proven to be a powerful technique in biophysical research. This technique becomes an indispensable tool for high-resolution receptor mapping as it has been successfully demonstrated on different biomolecular model systems. In these studies, the topographical imaging of receptor molecules is combined with molecular recognition by their cognate ligands bound to the atomic force microscope (AFM) tip via a flexible and distensible tether. In this review, we describe the principles of TREC imaging and provide a flavour of its recent application on endothelial cells. PMID:21812052</p> <div class="credits"> <p class="dwt_author">Chtcheglova, L A; Hinterdorfer, P</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">289</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2006Sci...312.1344A"> <span id="translatedtitle">Mass and Local <span class="hlt">Topography</span> Measurements of Itokawa by Hayabusa</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The ranging instrument aboard the Hayabusa spacecraft measured the surface <span class="hlt">topography</span> of asteroid 25143 Itokawa and its mass. A typical rough area is similar in roughness to debris located on the interior wall of a large crater on asteroid 433 Eros, which suggests a surface structure on Itokawa similar to crater ejecta on Eros. The mass of Itokawa was estimated as (3.58 +/- 0.18) × 1010 kilograms, implying a bulk density of (1.95 +/- 0.14) grams per cubic centimeter for a volume of (1.84 +/- 0.09) × 107 cubic meters and a bulk porosity of ~40%, which is similar to that of angular sands, when assuming an LL (low iron chondritic) meteorite composition. Combined with surface observations, these data indicate that Itokawa is the first subkilometer-sized small asteroid showing a rubble-pile body rather than a solid monolithic asteroid.</p> <div class="credits"> <p class="dwt_author">Abe, Shinsuke; Mukai, Tadashi; Hirata, Naru; Barnouin-Jha, Olivier S.; Cheng, Andrew F.; Demura, Hirohide; Gaskell, Robert W.; Hashimoto, Tatsuaki; Hiraoka, Kensuke; Honda, Takayuki; Kubota, Takashi; Matsuoka, Masatoshi; Mizuno, Takahide; Nakamura, Ryosuke; Scheeres, Daniel J.; Yoshikawa, Makoto</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-06-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">290</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/16741111"> <span id="translatedtitle">Mass and local <span class="hlt">topography</span> measurements of Itokawa by Hayabusa.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">The ranging instrument aboard the Hayabusa spacecraft measured the surface <span class="hlt">topography</span> of asteroid 25143 Itokawa and its mass. A typical rough area is similar in roughness to debris located on the interior wall of a large crater on asteroid 433 Eros, which suggests a surface structure on Itokawa similar to crater ejecta on Eros. The mass of Itokawa was estimated as (3.58 +/- 0.18) x 10(10) kilograms, implying a bulk density of (1.95 +/- 0.14) grams per cubic centimeter for a volume of (1.84 +/- 0.09) x 10(7) cubic meters and a bulk porosity of approximately 40%, which is similar to that of angular sands, when assuming an LL (low iron chondritic) meteorite composition. Combined with surface observations, these data indicate that Itokawa is the first subkilometer-sized small asteroid showing a rubble-pile body rather than a solid monolithic asteroid. PMID:16741111</p> <div class="credits"> <p class="dwt_author">Abe, Shinsuke; Mukai, Tadashi; Hirata, Naru; Barnouin-Jha, Olivier S; Cheng, Andrew F; Demura, Hirohide; Gaskell, Robert W; Hashimoto, Tatsuaki; Hiraoka, Kensuke; Honda, Takayuki; Kubota, Takashi; Matsuoka, Masatoshi; Mizuno, Takahide; Nakamura, Ryosuke; Scheeres, Daniel J; Yoshikawa, Makoto</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-06-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">291</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012OptLE..50..231M"> <span id="translatedtitle">Leaf cuticle <span class="hlt">topography</span> retrieved by using fringe projection</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">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 <span class="hlt">topography</span> 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.</p> <div class="credits"> <p class="dwt_author">Martínez, Amalia; Rayas, J. A.; Cordero, Raúl R.; Balieiro, Daniela; Labbe, Fernando</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-02-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">292</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/3408352"> <span id="translatedtitle">[<span class="hlt">Topography</span> and structure of the stylohyoid muscle in mammals].</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary"><span class="hlt">Topography</span> and structure of the musculus stylohyoideus (MSH) have been studied in 78 species of Mammalia from 12 orders. The muscle in question has specific peculiarities not only in its position and fixation, but also in a great variability of its structure. The MSH is not revealed in Philander opossum, Lagostrophus fasciatus, guinea pig, Meriones eversmanni, Rhombomys opimus, Nyctereutes procyonoides, Thos aureus, Mastelidae. Various pathways of development and different functional loading define existence of several modifications of the MSH: a) the medial part of the muscle develops (Didelphys, Rodentia, Insectivora, Proboscidea, Dama dama, Capreolus capreolus; b) the lateral part of the musculus develops (Lagomorpha, Canis lupus, Ursidae, Felidae, Pinnipedia, Cavicornia); c) both parts of the musculus develop, determining position of the m. digastricus between these two parts (Alces alces, Pseudaxis sica, Cervus elaphus, Macaca rhesus, Erythrocebus patas, Perissodastyla). PMID:3408352</p> <div class="credits"> <p class="dwt_author">Rudik, S K</p> <p class="dwt_publisher"></p> <p class="publishDate">1988-04-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">293</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013EGUGA..15.7688P"> <span id="translatedtitle">Relations between heat flow, <span class="hlt">topography</span> and Moho depth for Europe</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The relation between heat flow, <span class="hlt">topography</span> and Moho depth for recent maps of Europe is presented. New heat flow map of Europe (Majorowicz and Wybraniec, 2010) is based on updated database of uncorrected heat flow values to which paleoclimatic correction is applied across the continental Europe. Correction is depth dependent due to a diffusive thermal transfer of the surface temperature forcing of which glacial-interglacial history has the largest impact. This explains some very low uncorrected heat flow values 20-30 mW/m2 in the shields, shallow basin areas of the cratons, and in other areas including orogenic belts were heat flow was likely underestimated. New integrated map of the European Moho depth (Grad et al., 2009) is the first high resolution digital map for European plate understand as an area from Ural Mountains in the east to mid-Atlantic ridge in the west, and Mediterranean Sea in the south to Spitsbergen and Barents Sea in Arctic in the north. For correlation we used: onshore heat flow density data with palaeoclimatic correction (5318 locations), <span class="hlt">topography</span> map (30 x 30 arc seconds; Danielson and Gesch, 2011) and Moho map (longitude, latitude and Moho depth, each 0.1 degree). Analysis was done in areas where data from all three datasets were available. Continental Europe area could be divided into two large domains related with Precambrian East European craton and Palaeozoic Platform. Next two smaller areas correspond to Scandinavian Caledonides and Anatolia. Presented results show different correlations between Moho depth, elevation and heat flow for all discussed regions. For each region more detailed analysis of these relation in different elevation ranges is presented. In general it is observed that Moho depth is more significant to HF then elevation. Depending on region and elevation range HF value in mW/m2 is up to two times larger than Moho depth in km, while HF relation to elevation varies much more.</p> <div class="credits"> <p class="dwt_author">Polkowski, Marcin; Majorowicz, Jacek; Grad, Marek</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-04-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">294</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://dx.doi.org/10.1016/j.pss.2007.04.015"> <span id="translatedtitle"><span class="hlt">Topography</span> and geomorphology of the Huygens landing site on Titan</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">The Descent Imager/Spectral Radiometer (DISR) aboard the Huygens Probe took several hundred visible-light images with its three cameras on approach to the surface of Titan. Several sets of stereo image pairs were collected during the descent. The digital terrain models constructed from those images show rugged <span class="hlt">topography</span>, in places approaching the angle of repose, adjacent to flatter darker plains. Brighter regions north of the landing site display two styles of drainage patterns: (1) bright highlands with rough <span class="hlt">topography</span> and deeply incised branching dendritic drainage networks (up to fourth order) with dark-floored valleys that are suggestive of erosion by methane rainfall and (2) short, stubby low-order drainages that follow linear fault patterns forming canyon-like features suggestive of methane spring-sapping. The topographic data show that the bright highland terrains are extremely rugged; slopes of order of 30?? appear common. These systems drain into adjacent relatively flat, dark lowland terrains. A stereo model for part of the dark plains region to the east of the landing site suggests surface scour across this plain flowing from west to east leaving ???100-m-high bright ridges. Tectonic patterns are evident in (1) controlling the rectilinear, low-order, stubby drainages and (2) the "coastline" at the highland-lowland boundary with numerous straight and angular margins. In addition to flow from the highlands drainages, the lowland area shows evidence for more prolific flow parallel to the highland-lowland boundary leaving bright outliers resembling terrestrial sandbars. This implies major west to east floods across the plains where the probe landed with flow parallel to the highland-lowland boundary; the primary source of these flows is evidently not the dendritic channels in the bright highlands to the north. ?? 2007 Elsevier Ltd. All rights reserved.</p> <div class="credits"> <p class="dwt_author">Soderblom, L. A.; Tomasko, M. G.; Archinal, B. A.; Becker, T. L.; Bushroe, M. W.; Cook, D. A.; Doose, L. R.; Galuszka, D. M.; Hare, T. M.; Howington-Kraus, E.; Karkoschka, E.; Kirk, R. L.; Lunine, J. I.; McFarlane, E. A.; Redding, B. L.; Rizk, B.; Rosiek, M. R.; See, C.; Smith, P. H.</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">295</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013CliPa...9.2365K"> <span id="translatedtitle">Pre-LGM Northern Hemisphere ice sheet <span class="hlt">topography</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We here reconstruct the paleotopography of Northern Hemisphere ice sheets during the glacial maxima of marine isotope stages (MIS) 5b and 4.We employ a combined approach, blending geologically based reconstruction and numerical modeling, to arrive at probable ice sheet extents and <span class="hlt">topographies</span> for each of these two time slices. For a physically based 3-D calculation based on geologically derived 2-D constraints, we use the University of Maine Ice Sheet Model (UMISM) to calculate ice sheet thickness and <span class="hlt">topography</span>. The approach and ice sheet modeling strategy is designed to provide robust data sets of sufficient resolution for atmospheric circulation experiments for these previously elusive time periods. Two tunable parameters, a temperature scaling function applied to a spliced Vostok-GRIP record, and spatial adjustment of the climatic pole position, were employed iteratively to achieve a good fit to geological constraints where such were available. The model credibly reproduces the first-order pattern of size and location of geologically indicated ice sheets during marine isotope stages (MIS) 5b (86.2 kyr model age) and 4 (64 kyr model age). From the interglacial state of two north-south obstacles to atmospheric circulation (Rocky Mountains and Greenland), by MIS 5b the emergence of combined Quebec-central Arctic and Scandinavian-Barents-Kara ice sheets had increased the number of such highland obstacles to four. The number of major ice sheets remained constant through MIS 4, but the merging of the Cordilleran and the proto-Laurentide Ice Sheet produced a single continent-wide North American ice sheet at the LGM.</p> <div class="credits"> <p class="dwt_author">Kleman, J.; Fastook, J.; Ebert, K.; Nilsson, J.; Caballero, R.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-10-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">296</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/21549232"> <span id="translatedtitle">Titanium surface <span class="hlt">topography</span> affects collagen biosynthesis of adherent cells.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Collagen-dependent microstructure and physicochemical properties of newly formed bone around implant surfaces represent key determinants of implant biomechanics. This study investigated the effects of implant surface <span class="hlt">topography</span> on collagen biosynthesis of adherent human mesenchymal stem cells (hMSCs). hMSCs were grown for 0 to 42 days on titanium disks (20.0 × 1.0 mm) with smooth or rough surfaces. Cell attachment and spreading were evaluated by incubating cells with Texas-Red-conjugated phalloidin antibody. Quantitative real-time PCR was used to measure the mRNA levels of Col1?1 and collagen modifying genes including prolyl hydroxylases (PHs), lysyl oxidases (LOXs) and lysyl hydroxylases (LHs). Osteogenesis was assessed at the level of osteoblast specific gene expression and alizarin red staining for mineralization. Cell layer-associated matrix and collagen content were determined by amino acid analysis. At 4h, 100% cells were flattened on both surfaces, however the cells on smooth surface had a fibroblast-like shape, while cells on rough surface lacked any defined long axis. PH, LH, and most LOX mRNA levels were greater in hMSCs grown on rough surfaces for 3 days. The mineralized area was greater for rough surface at 28 and 42 days. The collagen content (percent total protein) was also greater at rough surface compared to smooth surface at 28 (36% versus 26%) and 42 days (46% versus 29%), respectively (p<.05). In a cell culture model, rough surface <span class="hlt">topography</span> positively modulates collagen biosynthesis and accumulation and the expression of genes associated with collagen cross-linking in adherent hMSC. The altered biosynthesis of the collagen-rich ECM adjacent to endosseous implants may influence the biomechanical properties of osseointegrated endosseous implants. PMID:21549232</p> <div class="credits"> <p class="dwt_author">Mendonça, Daniela B S; Miguez, Patrícia A; Mendonça, Gustavo; Yamauchi, Mitsuo; Aragão, Francisco J L; Cooper, Lyndon F</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-04-27</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">297</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013CliPD...9.2557K"> <span id="translatedtitle">Pre-LGM Northern Hemisphere paleo-ice sheet <span class="hlt">topography</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We here reconstruct the paleotopgraphy of Northern Hemisphere ice sheets during the glacial maxima of marine isotope stages (MIS) 5b and 4. We employ two approaches, geologically based reconstruction and numerical modeling, in mutually supportive roles to arrive at probable ice sheet extents and <span class="hlt">topographies</span> for each of these two time slices. For a physically based 3-D calculation based on geologically derived 2-D constraints, we use the University of Maine Ice Sheet Model (UMISM) to calculate ice-sheet thickness and <span class="hlt">topography</span>. The approach and ice-sheet modeling strategy is designed to provide robust data sets of sufficient resolution for atmospheric circulation experiments for these previously elusive time periods. Two tunable parameters, a temperature scaling function applied to a spliced Vostok-GRIP record, and spatial adjustment of climatic pole position, were employed iteratively to achieve a good fit to geological constraints where such were available. The model credibly reproduces the first-order pattern of size and location of geologically indicated ice sheets during marine isotope stages (MIS) 5b (86.2 kyr model age) and 4 (64 kyr model age). From the interglacial state of two north-south obstacles to atmospheric circulation (Rocky Mountains and Greenland), by MIS 5b combined Quebec-Central Arctic and Scandinavian-Barents/Kara ice sheets had effectively increased the number of such highland obstacles to four. This number remained constant through MIS 4, but at the last glacial maximum (LGM) dropped to three, through the merging of the Cordilleran and the proto-Laurentide Ice Sheet to a single continent-wide North American ice sheet.</p> <div class="credits"> <p class="dwt_author">Kleman, J.; Fastook, J.; Ebert, K.; Nilsson, J.; Caballero, R.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">298</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2011AGUFM.P44B..07H"> <span id="translatedtitle">Density constraints of lunar upper crust from gravity and <span class="hlt">topography</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Remote sensing and in situ measurements have shown that there are large lateral and vertical variations in the composition of the lunar crust. These crustal density diversities can be investigated using newly obtained global gravity and <span class="hlt">topography</span> data. We applied a localized spectral admittance technique to various crustal regions by windowing the free-air gravity and surface <span class="hlt">topography</span> with the band-limited localization windows of Wieczorek and Simons (2005, 2007). These admittances were interpreted using a geophysical model that includes both surface and subsurface loads that are supported by an elastic lithosphere. By varying the crustal density, elastic thickness and loading ratio in certain ranges, the best fitting bulk densities for a number of homogeneous regions were constrained to vary laterally from 2590 kg m-3 to 3010 kg m-3, with a mean value of 2700 kg m-3. Assuming the composition of the upper crust is uniform, the porosity of the upper crust could be determined if the pore-free surface density is known. Based on the known compositions of lunar rocks and estimated mineralogical norms, we found that the pore-free densities of lunar rocks were highly correlated with FeO and TiO2 abundance. The rock density can vary from 2884 to 3038 kg m-3 in estimated regions by using the iron and titanium abundances from Lunar Prospector gamma-ray spectrometer. We calculated the porosity of each region and found a mean value of ~7.4±3.4%, with permissible values from 0 to 14%. Furthermore, we took into account the vertical variation of crust density, and developed a novel technique that the density profile of the crust could be inverted using higher resolution gravity models. Since all these analyses are challenging using the recent Kaguya gravity models, higher resolution gravity data expected from NASA's Gravity Recovery and Interior Laboratory (GRAIL) mission would place tight constrains on both the lateral and vertical density variations of the lunar crust.</p> <div class="credits"> <p class="dwt_author">Huang, Q.; Wieczorek, M. A.; Ping, J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">299</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3641517"> <span id="translatedtitle">Nicotine intake and smoking <span class="hlt">topography</span> in smokers with bipolar disorder</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Objectives Cigarette smoking behavior in bipolar disorder (BPD), including the effects of mood-stabilizing medications, has not been well characterized. Methods We compared serum nicotine, nicotine metabolite levels, and smoking <span class="hlt">topography</span> in 75 smokers with BPD to 86 control smokers (CON). For some comparisons, an additional control group of 75 smokers with schizophrenia (SCZ) were included. Results There were no differences between the BPD and CON groups in baseline smoking characteristics or serum nicotine or cotinine levels. Fifty-one smokers with BPD (68.9%) were taking one of the following mood stabilizers: valproic acid, lamotrigine, carbamazepine, oxcarbazepine, lithium, or topiramate. The 3-hydroxycotinine-to-cotinine ratio, a marker of cytochrome P450 2A6 (CYP2A6) metabolic activity, was significantly higher in BPD versus CON and versus SCZ (0.68 versus 0.49 versus 0.54; p = 0.002). The difference between groups, however, was no longer significant when the analysis was repeated with those taking hepatic enzyme-inducing drugs (carbamazepine, oxcarbazepine, and topiramate) included as a covariate. The time between puffs, or interpuff interval (IPI), was shorter in BPD versus CON by an average of 3.0 sec (p < 0.05), although this was no longer significant when we removed smokers from the analysis of those taking hepatic enzyme inducers. Conclusions Smokers with BPD are not different from CON on most measures of nicotine intake and smoking <span class="hlt">topography</span>. We found an increased rate of nicotine metabolism in smokers taking mood stabilizers that are hepatic enzyme inducers, including carbamazepine, oxcarbazepine, and topiramate. Smokers with rapid nicotine metabolism might be expected to smoke more intensely to compensate for the more rapid disappearance of nicotine from the blood and brain, and may have more difficulty in quitting smoking, although this requires further study.</p> <div class="credits"> <p class="dwt_author">Williams, Jill M; Gandhi, Kunal K; Lu, Shou-En; Steinberg, Marc L; Benowitz, Neal L</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">300</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1999nvm..conf...52R"> <span id="translatedtitle">Lunar South Pole <span class="hlt">Topography</span> Derived from Clementine Imagery</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">During the Clementine Mission both oblique and vertical multispectral images were collected. The oblique and vertical images from a single spectral band collected during the same orbit form a stereo pair that can be used to derive the <span class="hlt">topography</span>. These stereo pairs are being used to derive the <span class="hlt">topography</span> of an area (90 deg S to 650S latitude) surrounding the lunar south pole. Work on the lunar north pole <span class="hlt">topography</span> will start after completion of the south pole <span class="hlt">topography</span>. This report provides an update on the initial results for the lunar south pole <span class="hlt">topography</span>. In 1994, the Clementine spacecraft acquired digital images of the Moon at visible and near-infrared wavelengths. Onboard there were four camera systems and a laser altimeter. During the first pass, periapsis was at 30S and the highest resolution images were obtained in the southern hemisphere. Over the northern polar area, a series of oblique and vertical images were obtained with the ultraviolet-visible (UV-VIS) camera on each orbit. During the second pass, periapsis was at 30N and the image acquisition strategy was reversed. The UV-VIS camera image size was 384 x 288 pixels with five spectral bands and one broad band. The 750-nm-band stereo pairs are the primary image source for this study. The ground sample distances (GSD) for oblique images range from 300 to 400m. The GSD for the vertical images, acquired at the end of an orbit, are slightly larger and range from 325 to 450 m. Using the formula for stereo-height accuracy, an estimate of height accuracy is 180m. This formula is IFOVMAX)/(K*B/H with IFOVMAX defined as Maximum Instantaneous Field of View; B/H is the base-to-height ratio and K is an estimate of pixel measurement accuracy on the imagery. The Clementine laser altimeter (LIDAR) data were used previously to produce a global topographic model of the Moon . The model has a vertical accuracy of about 100 m and a spatial resolution of 2.5 deg. Altimetry data were collected between 79S and 810N. These data were filtered and then interpolated to fill in the polar regions where the altimeter did not collect data. A global <span class="hlt">topography</span> model was then derived based on spherical harmonic expansion. Image mosaic. A global image mosaic of the Moon was produced from the 750-nm. Clementine data . The mosaic includes high-resolution, oblique, and vertical images. Match points were picked to tie the imagery together, and the camera pointing angles were adjusted to align the imagery. This adjustment used a spherical surface, and the elevation of all points was held to a constant value, 1737.4 km. This produced a seamless image mosaic with latitude and longitude information but no information on the elevation. The imagery and support information were downloaded to our digital photogrammetric workstation from the Integrated Software for Imagers and Spectrometers (ISIS) system. The support data included the camera location and pointing angles. Match points used to, produce the image mosaic were also downloaded. The camera angles were adjusted to account for the elevation of the match points. This was accomplished with the Multi Sensor Triangulation (MST) software from LH Systems SOCET Set software package. The revised camera angles allowed for the derivation of a digital elevation model (DEM) from the stereo pairs. The match-point latitude and longitude from the global image mosaic are accurate and used for an initial estimate of the horizontal position. The elevations of the match points were estimated from the altimetry data. The camera angles used in the altimetry processing and in the creation of the image mosaic were adjusted independently. Hence, the horizontal position of the altimetry data and the image mosaic are not aligned correctly. Clementine was designed so the altimeter shared the optical system of the HIRES camera system. The HIRES and UV-VIS camera systems were aligned so the HIRES image was centered in the UV-VIS image. We therefore made an adjustment so that the altimetry points would fall near the centerline of the UV-VIS imagery. A DEM was created from</p> <div class="credits"> <p class="dwt_author">Rosiek, M. R.; Kirk, R.; Howington-Kraus, A.</p> <p class="dwt_publisher"></p> <p class="publishDate">1999-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_14");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return 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href="#">11</a> <a onClick='return showDiv("page_12");' href="#">12</a> <a onClick='return showDiv("page_13");' href="#">13</a> <a onClick='return showDiv("page_14");' href="#">14</a> <a onClick='return showDiv("page_15");' href="#">15</a> <a style="font-weight: bold;">16</a> <a onClick='return showDiv("page_17");' href="#">17</a> <a onClick='return showDiv("page_18");' href="#">18</a> <a onClick='return showDiv("page_19");' href="#">19</a> <a onClick='return showDiv("page_20");' href="#">20</a> <a onClick='return showDiv("page_21");' href="#">21</a> <a onClick='return showDiv("page_22");' href="#">22</a> <a onClick='return showDiv("page_23");' href="#">23</a> <a onClick='return showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_17");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">301</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2011JPhCS.311a2022M"> <span id="translatedtitle">Surface <span class="hlt">topography</span> of cylindrical gear wheels after smoothing in abrasive mass, honing and shot peening</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The present paper presents the analysis of surface <span class="hlt">topography</span> of gear teeth as the result of final machining processes. Teeth of multiple cylindrical gears shaped by grinding were smoothed in abrasive mass, honed or shot peened. The measurement of gears were made using coordinate measuring machine and 3D surface <span class="hlt">topography</span> stylus instrument. The following deviations were studied; pitch deviation, total pitches deviations, variation of teeth thickness and deviation of gear radial run-out. Changes in teeth surface <span class="hlt">topography</span> during machining process were determined. 3D surface <span class="hlt">topography</span> parameters, surface directionality as well as areal autocorrelation and power spectral density functions were taken into consideration. As the results of the analysis, the best surface <span class="hlt">topography</span> with regard to gear operational properties was recommended.</p> <div class="credits"> <p class="dwt_author">Michalski, J.; Pawlus, P.; ?elasko, W.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-08-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">302</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1993LPI....24..797K"> <span id="translatedtitle">An inversion of geoid and <span class="hlt">topography</span> for mantle and crustal structure on Mars</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Mars has the largest amplitude geoid anomalies and surface <span class="hlt">topography</span> known on the terrestrial planets. A number of prior studies have analyzed Martian gravity anomalies and <span class="hlt">topography</span> in terms of isostasy and flexure of the crust and lithosphere. Other studies have emphasized the role of mantle convection in producing gravity anomalies and <span class="hlt">topography</span> in some regions of Mars. Geoid and <span class="hlt">topography</span> observations for simultaneous estimates of density anomalies in the crust and mantle of Mars are inverted. In performing this study, a recent degree 50 spherical harmonic expansion of the Martian gravity field (GMM-l) and a corresponding resolution expansion of the USGS Mars <span class="hlt">topography</span> model are used. However, our analysis is restricted to harmonic degrees up to L equals 25, which are better determined than the higher harmonics. This provides a half-wavelength horizontal resolution of 425 km.</p> <div class="credits"> <p class="dwt_author">Kiefer, Walter; Bills, Bruce; Frey, Herb; Nerem, Steve; Roark, Jim; Zuber, Maria</p> <p class="dwt_publisher"></p> <p class="publishDate">1993-03-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">303</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/42033642"> <span id="translatedtitle"><span class="hlt">Topography</span> of the ocean floor: Thermal evolution of the lithosphere and interaction of deep mantle heterogeneities with the lithosphere</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary"><span class="hlt">Topography</span> associated with large wavelength geoid is derived by two methods. First, the bathymetry corrected for sediment loading is decomposed using a least-squares method as a function of age plus terms proportional to the geoid. The <span class="hlt">topography</span> at old ages is flatter than predicted by the &surd;Age law. At degrees 2 and 3, very little <span class="hlt">topography</span> is associated with the</p> <div class="credits"> <p class="dwt_author">Paul Colin; Luce Fleitout</p> <p class="dwt_publisher"></p> <p class="publishDate">1990-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">304</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/39854412"> <span id="translatedtitle">The use of scanning electron microscopy to study the ion beam sputter modification of the surface <span class="hlt">topography</span> of biological implants</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">One factor which affects the biological tissue response to an implant material is the surface <span class="hlt">topography</span> of the material. Ion beam sputtering, as a potentially useful roughening technique, has recently been used in attempts to modify the surface <span class="hlt">topography</span> of biocompatible materials, such as metals, alloys, polymers, and ceramics. The ion-beam sputter modification of the surface <span class="hlt">topography</span> of three different</p> <div class="credits"> <p class="dwt_author">Zbigniew W. Kowalski</p> <p class="dwt_publisher"></p> <p class="publishDate">1982-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">305</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1998HyPr...12.1151T"> <span id="translatedtitle">Modelling wetting and drying effects over complex <span class="hlt">topography</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The numerical simulation of free surface flows that alternately flood and dry out over complex <span class="hlt">topography</span> is a formidable task. The model equation set generally used for this purpose is the two-dimensional (2D) shallow water wave model (SWWM). Simplified forms of this system such as the zero inertia model (ZIM) can accommodate specific situations like slowly evolving floods over gentle slopes. Classical numerical techniques, such as finite differences (FD) and finite elements (FE), have been used for their integration over the last 20-30 years. Most of these schemes experience some kind of instability and usually fail when some particular domain under specific flow conditions is treated. The numerical instability generally manifests itself in the form of an unphysical negative depth that subsequently causes a run-time error at the computation of the celerity and/or the friction slope. The origins of this behaviour are diverse and may be generally attributed to:1. The use of a scheme that is inappropriate for such complex flow conditions (mixed regimes).2. Improper treatment of a friction source term or a large local curvature in <span class="hlt">topography</span>.3. Mishandling of a cell that is partially wet/dry.In this paper, a tentative attempt has been made to gain a better understanding of the genesis of the instabilities, their implications and the limits to the proposed solutions. Frequently, the enforcement of robustness is made at the expense of accuracy. The need for a positive scheme, that is, a scheme that always predicts positive depths when run within the constraints of some practical stability limits, is fundamental. It is shown here how a carefully chosen scheme (in this case, an adaptation of the solver to the SWWM) can preserve positive values of water depth under both explicit and implicit time integration, high velocities and complex <span class="hlt">topography</span> that may include dry areas. However, the treatment of the source terms: friction, Coriolis and particularly the bathymetry, are also of prime importance and must not be overlooked. Linearization with a combination of switching between explicit-implicit integration can overcome the stiffness of the friction and Coriolis terms and provide stable numerical integration. The treatment of the bathymetry source term is much more delicate. For cells undergoing a transient wet-dry process, the imposition of zero velocity stabilizes most of the approximations. However, this artificial zero velocity condition can be the cause of considerable error, especially when fast moving fronts are involved. Besides these difficulties linked with the internal position of the front within a cell versus the limited resolution of a numerical grid, it appears that the second derivative that defines whether the bed is locally convex or concave is a key indicator for stability. A convex bottom may lead to unbounded solutions. It appears that this behaviour is not linked to the numerics (numerical scheme) but rather to the mathematical theory of the SWWM. These concerns about stability have taken precedence, until now, over the crucial and related question of accuracy, especially near a moving front, and how these possible inaccuracies at the leading edge may affect the solution at interior points within the domain.This paper presents an in depth, fully two-dimensional space analysis of the aforementioned problem that has not been addressed before. The purpose of the present communication is not to propose what could be viewed as a final solution, but rather to provide some key considerations that may reveal the ingredients and insight necessary for the development of accurate and robust solutions in the future.</p> <div class="credits"> <p class="dwt_author">Tchamen, G. W.; Kahawita, R. A.</p> <p class="dwt_publisher"></p> <p class="publishDate">1998-06-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">306</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012EGUGA..1410599H"> <span id="translatedtitle">Hysteresis in transient landscape <span class="hlt">topography</span> recorded by hillslopes.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">On hillslopes considered to be at steady-state, hillslope morphology reflects the rate of denudation and the processes transporting sediment. Roering et al. [2007] expanded the commonly implemented non-linear sediment transport law to predict steady-state hillslope morphology as a function of erosion rate in a non-dimensional framework. This framework allows dimensionless erosion rate and relief to be predicted on the basis of topographic parameters readily predicted from high resolution digital elevation models (LiDAR). Here we extract hilltop curvature (Laplacian), hillslope gradients and hillslope lengths throughout a landscape with a well constrained uplift field in order to search for deviation in hillslope morphology when the steady-state assumption is violated. The Dragon's Back Pressure Ridge, immediately adjacent to the San Andreas Fault (SAF), is a series of south-west trending valleys, approximately perpendicular to SAF, generated as dextral fault motion carries the Pacific plate of a 'knuckle' of uplift which is pinned to the North American plate [Hilley and Arrowsmith, 2008]. As such the <span class="hlt">topography</span> has been generated by passing through the zone of uplift and subsequently relaxing as it comes out the other side. This facilitates a space-for-time substitution and allows extraction of a time series of hillslope evolution in response to active uplift and erosion and subsequent landscape relaxation during tectonic quiescence over a period of 130 ka. We find that the morphological response of hillslopes to increased surface uplift is markedly different from the response to cessation of uplift. During increased uplift, hillslopes steepen, and hilltops get sharper. This morphological response is near instantaneous, implying that the response time scale for hillslopes to increased valley incision is extremely rapid. Subsequent drainage reorganisation occurs as uplift continues so that hillslopes tend to get longer with time spent in the uplift zone; possibly due to increased landslide frequency escalating the efficiency of hillslope sediment transport relative to valley erosion. During relaxation hilltop curvature and hillslope gradient decline gradually over 50 ka, implying that response time is much longer when a hillslope is responding to a reduction in surface uplift. Non-dimensional analysis reveals that hillslope morphology is markedly different for similar erosion rates depending on whether the landscape is being rejuvenated or relaxing. Hence our ability to interpret rates of tectonic processes based on <span class="hlt">topography</span> alone may require a priori interpretation of the history tectonic conditions.</p> <div class="credits"> <p class="dwt_author">Hurst, M. D.; Mudd, S. M.; Attal, M.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-04-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">307</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2000PhDT.......105S"> <span id="translatedtitle">Correlation of process with <span class="hlt">topography</span> evolution during reactive ion etching</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We present a low-cost, high-speed, high-accuracy in situ thin film measurement system for real-time process monitoring and industrial process control. This sensor, the two-channel spectroscopic reflectometer (2CSR), is a hybrid of spectroscopic ellipsometry (SE) and spectroscopic reflectometry (SR). In 2CSR a polarized beam of white light is directed at the sample. The reflected light is resolved into its two orthogonal components, s and p, using a Wollaston prism. These data are recorded simultaneously as a function of wavelength using a two-channel spectrometer with linear array detectors. The fact that 2CSR has no moving parts, coupled with the use of the two-channel linear array detectors, enables high accuracy-data acquisition across the sensor's spectral range in 6ms. This makes the 2CSR ideal for real-time high-speed process monitoring and control in an industrial setting. We show accurate in situ, high-speed film thickness measurements during the plasma etches of both silicon dioxide and polycrystalline silicon samples. Additionally, we illustrate some of the advantages of in situ metrology for statistical process characterization and process control applications. We demonstrate an improved polysilicon optical model which accounts for both the scattering losses due to non- specular reflections from the surface and for the change in the polarizability of the surface roughness layer due to the inclusions of voids. We find that at near normal incidence the scattering effects dominate while at larger angles of incidence the combined model is less sensitive to scattering effects and the effective media effects begin to dominate. Finally, we show the first ever analysis of real-time in situ measurements of the reflectance from a grating structure while it is being etched, from which the <span class="hlt">topography</span> of the grating is extracted. We use the 2CSR to measure the s and p reflectances in real-time and analyze the data off-line using the Rigorous Coupled Wave Analysis. We performed scanning electron microscopy (SEM) on representative samples which were etched to different depths and successfully compared the micrographs to the RCWA extracted <span class="hlt">topography</span> down to the limit of our SEM.</p> <div class="credits"> <p class="dwt_author">Stutzman, Brooke Suzanne</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">308</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013JCoPh.242..544I"> <span id="translatedtitle">Augmented Lagrangian for shallow viscoplastic flow with <span class="hlt">topography</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In this paper we have developed a robust numerical algorithm for the visco-plastic Saint-Venant model with <span class="hlt">topography</span>. For the time discretization an implicit (backward) Euler scheme was used. To solve the resulting nonlinear equations, a four steps iterative algorithm was proposed. To handle the non-differentiability of the plastic terms an iterative decomposition-coordination formulation coupled with the augmented Lagrangian method was adopted. The proposed algorithm is consistent, i.e. if the convergence is achieved then the iterative solution satisfies the nonlinear system at each time iteration. The equations for the velocity field are discretized using the finite element method, while a discontinuous Galerkin method, with an upwind choice of the flux, is adopted for solving the hyperbolic equations that describe the evolution of the thickness. The algorithm permits to solve alternatively, at each iteration, the equations for the velocity field and for the thickness.The iterative decomposition coordination formulation coupled with the augmented Lagrangian method works very well and no instabilities are present. The proposed algorithm has a very good convergence rate, with the exception of large Reynolds numbers (Re?1000), not involved in the applications concerned by the shallow viscoplastic model. The discontinuous Galerkin technique assure the mass conservation of the shallow system. The model has the exact C-property for a plane bottom and an asymptotic C-property for a general <span class="hlt">topography</span>.Some boundary value problems were selected to analyze the robustness of the numerical algorithm and the predictive capabilities of the mechanical model. The comparison with an exact rigid flow solution illustrates the accuracy of the numerical scheme in handling the non-differentiability of the plastic terms. The influence of the mesh and of the time step are investigated for the flow of a Bingham fluid in a talweg. The role of the material cohesion in stopping a viscoplastic avalanche on a talweg with barrier was analyzed. Finally, the capacities of the model to describe the flow of a Bingham fluid on a valley from the broken wall of a reservoir situated upstream were investigated.</p> <div class="credits"> <p class="dwt_author">Ionescu, Ioan R.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-06-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">309</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2001JGR...10623811G"> <span id="translatedtitle">Martian wrinkle ridge <span class="hlt">topography</span>: Evidence for subsurface faults from MOLA</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Mars Orbiter Laser Altimeter (MOLA) <span class="hlt">topography</span> shows distinct elevation offsets across wrinkle ridges that can be explained simply by subsurface thrust faults. MOLA has provided the first reliable topographic data of wrinkle ridges to test models for their origin; although previous work has shown that wrinkle ridges result from compressional folding and faulting of near-surface units, the role of thrust faulting and its depth penetration have been argued. Topographic profiles across wrinkle ridges in Solis Planum, Lunae Planum, Tempe Terra, Xanthe Terra, Arcadia, Terra Sirenum, Thaumasia Planum, Arabia Terra, Syrtis Major, and Hesperia Planum show characteristic features such as superposed hills, crenulations, and elevation offsets between the plains on either side of the ridge. The characteristic elevation offsets between plains surfaces on either side of the ridges shown by MOLA are easily explained by subsurface thrust faults that underlie the ridges and produce the offset. In Solis Dorsa, wrinkle ridges are 10-20 km wide (well resolved by the 300 m spaced MOLA elevations), have a total relief of 80-250 m, and have elevation offsets of 50-180 m (well above the uncertainty in the MOLA elevations). MOLA <span class="hlt">topography</span> shows that the plains decrease in elevation toward the southeast and are deformed into folds or arches not visible in images that are parallel to and in between the ridges. The elevations of the plains on either side of the ridges in Solis and Lunae Plana are characteristically down to the southeast and east, respectively, suggesting that faults beneath the wrinkle ridges offset the plains. This offset indicates underlying thrust faults that dip to the northwest and west, respectively, and systematically lower the southeast side of the plains. The observation that the elevation offsets across the ridges are maintained to the next ridge implies that the thrust fault penetrates to depths of tens of kilometers and thus well into the mechanical lithosphere. Small foreland basement uplifts on Earth, in which slip on shallowly dipping thrust faults in the crystalline basement is accommodated by folding in the overlying sedimentary rocks, appear to be broadly analogous to these groups of wrinkle ridges and suggest that they are examples of thick-skinned compressional deformation on Mars. These observations are not consistent with models for the formation of wrinkle ridges that involve folding of near-surface layers only or subsurface thrust faults that flatten into decollements at shallow depths.</p> <div class="credits"> <p class="dwt_author">Golombek, M. P.; Anderson, F. S.; Zuber, M. T.</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-10-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">310</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2006GeoJI.165..336M"> <span id="translatedtitle">The Zagros folded belt (Fars, Iran): constraints from <span class="hlt">topography</span> and critical wedge modelling</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The Late Miocene tectonics of the Zagros folded belt (Fars province) has for long been related solely to folding of the cover controlled by a ductile décollement between basement and the sedimentary cover. However, geological constraints, <span class="hlt">topography</span> analysis and seismotectonic studies reveal that basement thrusting may produce locally significant deformation in the cover. To determine how the deep-seated deformation in the basement may contribute to the overall <span class="hlt">topography</span> we first examine the filtered large and short wavelengths of the <span class="hlt">topography</span>. We find that the short-wavelength component of the <span class="hlt">topography</span> (20-25 km), including the Zagros folds, is superimposed on the differential uplift at the regional scale. In other words, the regional base level of folded marker horizons remains parallel to the regional <span class="hlt">topography</span> of interest. Modelling reveals that the salt-based wedge model, alone, is not able to reproduce the large-wavelength component of the <span class="hlt">topography</span> of the Zagros Folded Belt. This reveals that when a thick (relatively to its overburden) layer of salt forms the basal décollement it is generally too weak and cannot support the growth of significant <span class="hlt">topography</span>. We then test an alternative thick-skinned crustal wedge model involving the crust of the Arabian margin, which is decoupled above a viscous lower crust. This model satisfactorily reproduces the observed <span class="hlt">topography</span> and is consistent with present-day basement thrusting, <span class="hlt">topography</span> analyses and geological constraints. We conclude that basement-involved thickening and shortening is mechanically required to produce the shape of the Zagros Folded Belt since at least 10 Ma. Finally, the involvement of the basement provides mechanical and kinematic constraints that should be accounted for cross-sections balancing and further assessing the evolution of Zagros at crustal or lithospheric scales.</p> <div class="credits"> <p class="dwt_author">Mouthereau, F.; Lacombe, O.; Meyer, B.</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-04-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">311</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2010EGUGA..12.8452S"> <span id="translatedtitle">Modeling the impact of <span class="hlt">topography</span> on seismic amplification at regional scale</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The intensity of earthquake triggered ground shaking is influenced by the characteristics of earthquake source, medium and site effects. These site effects are often not included in the regional ground shaking models, especially the local <span class="hlt">topography</span>. It is being experimentally proved and noticed during many previous earthquakes, that <span class="hlt">topography</span> has significant impact on variation of ground shaking and subsequent building damages. Majority of the previous studies investigating the topographic impact on seismic response are limited to synthetic environments or isolated hills. This study deals with exploring the impact of <span class="hlt">topography</span> on variation of ground shaking caused by the 2005 Kashmir earthquake, at a regional scale. With the proliferation of remote sensing technologies, digital elevation models (DEMs) are freely and readily available at medium resolution, and with global cover. DEMs derived from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), with 30m resolution, and Shuttle Radar <span class="hlt">Topography</span> Mission (SRTM), with 90m resolution, can therefore be utilized to model and predict the impact of <span class="hlt">topography</span> on seismic response, also quickly after a seismic event. The <span class="hlt">topography</span> of the 2005 Kashmir earthquake affected area is derived from ASTER and SRTM DEMs and analyzed using a 3D spectral finite element code (SPECFEM3D). SPECFEM3D takes into account the seismic source parameters, medium and <span class="hlt">topography</span> to generate shake maps and earthquake simulations. The ground shaking simulations and peak ground acceleration maps were generated initially assuming the homogenous ground surface and later by including the <span class="hlt">topography</span> to assess the role of <span class="hlt">topography</span> in seismic amplification. <span class="hlt">Topography</span> derived from ASTER and SRTM DEMs were simulated separately to predict the impact of DEM resolution on computed ground shaking simulations and maps. The preliminary result from the model simulations shows that seismic waves were dispersed at topographic discontinuities, leading to intensification of seismic response at hill ridges. Comparing the simulations with and without <span class="hlt">topography</span> confirmed that the ground shaking was intensified at the hill ridges and steep slopes upto 5 times. Therefore, this study shows the considerable impact of <span class="hlt">topography</span> on variation of ground shaking and how seismic response modeling can benefit from the readily available global DEMs and SPECFEM3D in modeling earthquake impact more realistic and as early warning technique.</p> <div class="credits"> <p class="dwt_author">Shafique, Muhammad; Anggraeni, Dita; Bakker, Wim; van der Meijde, Mark</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">312</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2009AGUFMGP33A0728L"> <span id="translatedtitle">TEM simulation with <span class="hlt">topography</span> using boundary-fitted grid</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Finite-Difference Time-Domain (FDTD) method has been successfully used in transient electromagnetic (TEM) simulation. Until recently, however, <span class="hlt">topography</span> seems to be commonly neglected. To assess the topographic effect in TEM, some authors used a staircase approximation to the earth-air interface. But this approach might have two problems: first, its error might be very large; second, since air layer is explicitly included in FDTD computation, a very small time step is necessary to maintain the stability condition, which makes it inefficient. Another method to account for the tomography is using a non-Cartesian grid which is conformed to the boundary. In fact such boundary-fitted grids have been widely used in computational fluid dynamics to approximate the irregular boundary. In this study, we use a FDTD method combining boundary-fitted grids with the classical staggered grid, unconditional stable DuFort-Frankel scheme to discrete the quasi-static Maxwell equation. Since TEM simulation needs to step to a very late time, air layer had better not be included in FDTD computation. Instead, the boundary condition at the earth-air interface is handled via upward continuation. As the interface is generally not flat, the traditional FFT approach in upward continuation needs some modification. We use a method similar to the equivalent source method in gravity upward continuation, which required several FFT iterations to refine the results. We will report the preliminary results of our method and test its accuracy and efficiency with other methods.</p> <div class="credits"> <p class="dwt_author">Li, D.; Huang, Q.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">313</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2224113"> <span id="translatedtitle"><span class="hlt">TOPOGRAPHY</span> OF THE ORGANIC COMPONENTS IN MOTHER-OF-PEARL</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">1. The <span class="hlt">topography</span> of the organic components (conchiolin) has been investigated on positive, postshadow-cast, formvar, and carbon replicas of mother-of-pearl from shells of a Cephalopod, of two Gastropods, and of six Pelecypods. All these shells are characterized by a true nacreous inner shell layer. 2. The material included normal shell surfaces, fragments of cleavage obtained by fracture, and surfaces polished tangentially and transversally to the inner surface of the shells. Replicas of these surfaces were prepared before and after etching of graded heaviness, induced by a chelating agent (sequestrene NA 2, titriplex III). Micrographs of the successive steps of the process of corrosion have been recorded. 3. Corrosion unmasked, on the nacreous surfaces, organic membranes or sheets, running as continuous formations in between adjacent mineral lamellae, and separating the individual crystals of aragonite which are aligned in rows and constitute each lamella. 4. The interlamellar sheets of material exhibit a reticulated structure, which is especially visible in preparations orientated tangentially to the lamellae and to the tabular surface of the aragonite crystals. The pattern of this lace-like structure, different in the various species studied, appeared in the same species as closely similar to that reported previously in leaflets of thoroughly decalcified mother-of-pearl, dissociated by ultrasonic waves. The present results support former conclusions with regard to the existence of taxonomic differences between Cephalopods, Gastropods, and Pelecypods in the morphological organization of the organic phase within mother-of-pearl.</p> <div class="credits"> <p class="dwt_author">Gregoire, Charles</p> <p class="dwt_publisher"></p> <p class="publishDate">1957-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">314</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2001SPIE.4346..982K"> <span id="translatedtitle">Photoresist thickness variation due to local and global <span class="hlt">topography</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The control of photoresist thickness and uniformity is becoming more crucial factor as the wafer size increases and the minimum feature size decreases since the variation of resist thickness could affect the critical dimension variation. In general, spin coating technique is used to coat photoresist on a wafer. To obtain the wet resist thickness profile around a topographical feature, the analytical solution derived from mass continuity and lubrication approximation was used. Under the same spin coating condition, the formations of distributed photoresist were different among the shape and size of topology. The final dried resist thickness profile was obtained by applying the resist thickness reduction due to evaporation during soft bake. The photoresist thickness and distribution on an isolated topology were compared with those of a periodic topology. In case of periodic topology, the photoresist thickness and distribution are dependent on topology density. The resultant thickness variations were applied to our simulation tool to determine the line width variations around the topological feature. We found that the difference in resist thickness due to <span class="hlt">topography</span> could induce a severe line width variation. Mask bias or other correctional method is necessary to get the desired line width for the whole area around the topology.</p> <div class="credits"> <p class="dwt_author">Kim, Jin-Young; Bak, Heung-Jin; Sohn, Young-Soo; An, Ilsin; Bang, Kyoung-Yoon; Oh, Hye-Keun; Han, Woo-Sung</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-09-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">315</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012SPIE.8427E..77E"> <span id="translatedtitle">Corneal <span class="hlt">topography</span> reinterpretation through separate analysis of the projected rings</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We present a new algorithm to process captured images of reflected Placido rings. Up to our knowledge, conventional topographers transform from Cartesian to polar coordinates and vice-versa, thus extrapolating corneal data and introducing noise and image artefacts. Moreover, captured data are processed by the device according to proprietary algorithms and offering a final map of corneal curvature. Corneal <span class="hlt">topography</span> images consists of concentric rings of approximately elliptical shape. Our proposal consists of considering the information that provides each separate ring. A snake-annealing-like method permits identifying the ring even with discontinuities due to eye-lashes and reflections. By analysing the geometrical parameters of rings (centre, semi-axis and orientation), one can obtain information about small morphological micro-fluctuations and local astigmatisms. These parameters can be obtained with sub-pixel accuracy so the method results of high precision. The method can be easily adapted to work on any topographer, so that it can provide additional information about the cornea at no additional cost.</p> <div class="credits"> <p class="dwt_author">Espinosa, Julian; Roig, Ana B.; Mas, David; Hernández, Consuelo; Illueca, Carlos</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">316</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2004JGRE..10911005S"> <span id="translatedtitle">Extraction of Martian valley networks from digital <span class="hlt">topography</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We have developed a novel method for delineating valley networks on Mars. The valleys are inferred from digital <span class="hlt">topography</span> by an autonomous computer algorithm as drainage networks, instead of being manually mapped from images. Individual drainage basins are precisely defined and reconstructed to restore flow continuity disrupted by craters. Drainage networks are extracted from their underlying basins using the contributing area threshold method. We demonstrate that such drainage networks coincide with mapped valley networks verifying that valley networks are indeed drainage systems. Our procedure is capable of delineating and analyzing valley networks with unparalleled speed and consistency. We have applied this method to 28 Noachian locations on Mars exhibiting prominent valley networks. All extracted networks have a planar morphology similar to that of terrestrial river networks. They are characterized by a drainage density of ~0.1 km-1, low in comparison to the drainage density of terrestrial river networks. Slopes of ``streams'' in Martian valley networks decrease downstream at a slower rate than slopes of streams in terrestrial river networks. This analysis, based on a sizable data set of valley networks, reveals that although valley networks have some features pointing to their origin by precipitation-fed runoff erosion, their quantitative characteristics suggest that precipitation intensity and/or longevity of past pluvial climate were inadequate to develop mature drainage basins on Mars.</p> <div class="credits"> <p class="dwt_author">Stepinski, T. F.; Collier, M. L.</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-11-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">317</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013Icar..223...82N"> <span id="translatedtitle">Crater <span class="hlt">topography</span> on Titan: Implications for landscape evolution</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We present a comprehensive review of available crater <span class="hlt">topography</span> measurements for Saturn's moon Titan. In general, the depths of Titan's craters are within the range of depths observed for similarly sized fresh craters on Ganymede, but several hundreds of meters shallower than Ganymede's average depth vs. diameter trend. Depth-to-diameter ratios are between 0.0012 ± 0.0003 (for the largest crater studied, Menrva, D ˜ 425 km) and 0.017 ± 0.004 (for the smallest crater studied, Ksa, D ˜ 39 km). When we evaluate the Anderson-Darling goodness-of-fit parameter, we find that there is less than a 10% probability that Titan's craters have a current depth distribution that is consistent with the depth distribution of fresh craters on Ganymede. There is, however, a much higher probability that the relative depths are uniformly distributed between 0 (fresh) and 1 (completely infilled). This distribution is consistent with an infilling process that is relatively constant with time, such as aeolian deposition. Assuming that Ganymede represents a close 'airless' analogue to Titan, the difference in depths represents the first quantitative measure of the amount of modification that has shaped Titan's surface, the only body in the outer Solar System with extensive surface-atmosphere exchange.</p> <div class="credits"> <p class="dwt_author">Neish, C. D.; Kirk, R. L.; Lorenz, R. D.; Bray, V. J.; Schenk, P.; Stiles, B. W.; Turtle, E.; Mitchell, K.; Hayes, A.; Cassini Radar Team</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-03-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">318</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3681759"> <span id="translatedtitle">Substrate <span class="hlt">Topography</span> Determines Neuronal Polarization and Growth In Vitro</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">The establishment of neuronal connectivity depends on the correct initial polarization of the young neurons. In vivo, developing neurons sense a multitude of inputs and a great number of molecules are described that affect their outgrowth. In vitro, many studies have shown the possibility to influence neuronal morphology and growth by biophysical, i.e. topographic, signaling. In this work we have taken this approach one step further and investigated the impact of substrate <span class="hlt">topography</span> in the very early differentiation stages of developing neurons, i.e. when the cell is still at the round stage and when the first neurite is forming. For this purpose we fabricated micron sized pillar structures with highly reproducible feature sizes, and analyzed neurons on the interface of flat and topographic surfaces. We found that topographic signaling was able to attract the polarization markers of mouse embryonic neurons -N-cadherin, Golgi-centrosome complex and the first bud were oriented towards topographic stimuli. Consecutively, the axon was also preferentially extending along the pillars. These events seemed to occur regardless of pillar dimensions in the range we examined. However, we found differences in neurite length that depended on pillar dimensions. This study is one of the first to describe in detail the very early response of hippocampal neurons to topographic stimuli.</p> <div class="credits"> <p class="dwt_author">Micholt, Liesbeth; Gartner, Annette; Prodanov, Dimiter; Braeken, Dries; Dotti, Carlos G.; Bartic, Carmen</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">319</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013DPS....4530902L"> <span id="translatedtitle">Effects of <span class="hlt">topography</span> on the dune forming winds on Titan</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Cassini observed hundreds of dune fields on Titan, nearly all of which lie in the tropics and suggest westerly (from west to east) winds dominate at the surface. Most GCMs however have obtained easterly surface winds in the tropics, seemingly contradicting the wind direction suggested by the dunes. This has led to an active debate in the community about the origin of the dune forming winds on Titan and their direction and modality. This discussion is mostly driven by a study of Earth dunes seen as analogous to Titan. One can find examples of dunes on Earth that fit several wind regimes. To date only one GCM, that of Tokano (2008, 2010), has presented detailed analysis of its near surface winds and their dune forming capabilities. Despite the bulk of the wind being easterly, this GCM produces faster westerlies at equinox, thus transporting sand to the east. Our model, the Titan CAM (Friedson et al. 2009), is unable to reproduce the fast westerlies. Our GCM has been updated to include realistic <span class="hlt">topography</span> released by the Cassini radar team. Preliminary results suggest our tropical wind regime now has net westerly winds in the tropics, albeit weak. References: Tokano, T. 2008. Icarus 194, 243-262. Tokano, T. 2010. Aeolian Research 2, 113-127. Friedson, J. et al. 2009. Planet. Sp. Sci., 57, 1931-1949.</p> <div class="credits"> <p class="dwt_author">Larson, Erik J.; Toon, O. B.; Friedson, A. J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-10-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">320</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2838388"> <span id="translatedtitle">Contact Line Pinning by Microfabricated Patterns: Effects of Microscale <span class="hlt">Topography</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">We study how the microscale <span class="hlt">topography</span> of a solid surface affects the apparent advancing and receding angles at the contact line of a liquid drop pinned to this surface. Photolithographic methods are used to produce continuous circular polymer rings of varying cross-sectional size and shape on hydrophilic silicon wafer surfaces. Drops of water and glycerol are dispensed into the areas bounded by these rings, and critical apparent advancing and receding angles are measured and correlated with the parameters that characterize the ring cross-section. For much of the examined parameter space, the apparent critical angles are independent of ring height and width and are determined primarily by the slope of the ring's sidewalls, consistent with a model due to Gibbs. For ring heights below a few micrometers, the critical angles decrease below the values predicted by the sidewall slopes alone. These results provide data for calculation of hysteresis on naturally rough surfaces, and demonstrate a simple method for controlling and enhancing contact line pinning on solid surfaces.</p> <div class="credits"> <p class="dwt_author">Kalinin, Yevgeniy V.; Berejnov, Viatcheslav; Thorne, Robert E.</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_15");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" 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showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_18");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">321</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/6861916"> <span id="translatedtitle">Surface-replica <span class="hlt">topography</span> of retinal pigment epithelium during phagocytosis.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">The initial step in retinal phagocytosis may be mediated by complementary recognition molecules on the pigment epithelial microvilli and outer segment membrane surfaces. These molecules may display a surface morphology which is related topographically to phagocytic events. In order to explore this, we have developed a method for replicating the membrane surfaces of rat pigment epithelial explants during phagocytosis of latex beads. The explants are fixed in a mixed aldehyde and osmium fixative and the basal surface glued to a coverslip. After dehydration and critical point drying, the tissue is replicated with platinum and carbon in a freeze-fracture apparatus using either rotary or unidirectional coating and the replicas are examined by transmission electron microscopy. The membrane surfaces of the pigment epithelial cells and their microvilli are studded with numerous surface particles varying in size from 20 to 50 nm that are closely packed and give a cobblestone appearance to the membrane <span class="hlt">topography</span>. During the early stages of phagocytosis, microvillous processes appear to spread over the beads and form branched processes as they contact bead surfaces. During bead engulfment the microvilli have shortened into flattened sheets with interdigitating processes overlapping the beads. These uptake sites resemble Venus' fly-traps, which as they close over the beads create craters in the membrane surfaces of the pigment epithelium. The crater-like uptake sites appear to flatten out in the later stages and form flattened membrane domains which are surrounded by crenulated membrane that displays an irregular particulate morphology. PMID:6861916</p> <div class="credits"> <p class="dwt_author">McLaughlin, B J; Boykins, L G; Seyfried, R S</p> <p class="dwt_publisher"></p> <p class="publishDate">1983-06-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">322</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2008AGUFM.U11C..04Z"> <span id="translatedtitle"><span class="hlt">Topography</span> of Equatorial Mercury from MESSENGER Flybys 1 and 2</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">During the first flyby of Mercury by the MESSENGER spacecraft on January 14, 2008, the Mercury Laser Altimeter (MLA) obtained a 3200-kilometer-long profile that spanned approximately 20% of the near- equatorial region of the planet. <span class="hlt">Topography</span> along that profile is characterized by a 5.2-kilometer dynamic range and approximately 1-kilometer root-mean-square roughness. Sampled craters are shallower than their counterparts on the Moon, at least in part because of Mercury's higher gravity. Crater floors vary in roughness and slope, which suggests complex modification over a range of length scales. However, the various contributions to crater geometry and the general nature of crater modification have been poorly constrained because no spacecraft images are yet available in the profiled hemisphere. On October 6, 2008, MESSENGER will make its second flyby of Mercury, with closest approach also near the equator but about 170° east of the earlier flyby. Closest approach distances are about 200 km in both cases, and a profile of comparable length to profile 1 is expected from flyby 2. The collective altimetry data, combined with high-resolution and color imaging of both profile regions, will contribute toward understanding Mercury's long- wavelength shape and the geological and geophysical processes that have operated at the planet's surface.</p> <div class="credits"> <p class="dwt_author">Zuber, M. T.; Smith, D. E.; Solomon, S. C.; Phillips, R. J.; Peale, S. J.; Head, J. W.; Hauck, S. A.; McNutt, R. L.; Oberst, J.; Neumann, G. A.; Lemoine, F. G.; Sun, X.; Barmouin-Jha, O.; Johnson, C. L.</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">323</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1997PhDT........15X"> <span id="translatedtitle">Wave diffraction over a multi-step <span class="hlt">topography</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Within the framework of linear potential theory, an eigenfunction expansion solution is developed to study the diffraction of free-surface waves that propagate over arbitrary two-dimensional bottom <span class="hlt">topography</span> in both normal and oblique incidence. A multi-step model is devised to approximate this kind of bottom configuration by using piecewise-step modules. The solutions for each module are matched at the neighboring depth discontinuities by imposing the continuity of the velocity potential and its gradient. In addition to the two-step cases of submarine trenches and submerged breakwaters, the model is also applied to the multi-step cases of a bottom-seated semi-cylinder, single and doubly ripple beds, and sloping beach. The wave diffraction characteristics, mostly the reflection and transmission coefficients, hydrodynamic forces, and phase shifts, are investigated for a range of wave frequencies, wave incidence angles, as well as different bottom configurations. Numerical results are presented and compared with the available predictions and experimental data of other researchers. The roles of evanescent modes (N) and discretization (M) are discussed and a guideline for choosing the appropriate values of N and M is suggested. The present method provides accurate results and is computationally efficient.</p> <div class="credits"> <p class="dwt_author">Xu, Yingfan</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">324</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2010HESSD...7.4635S"> <span id="translatedtitle">HESS Opinions "<span class="hlt">Topography</span> driven conceptual modelling (FLEX-Topo)"</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Heterogeneity and complexity of hydrological processes offer substantial challenges to the hydrological modeller. Some hydrologists try to tackle this problem by introducing more and more detail in their models, or by setting-up more and more complicated models starting from basic principles at the smallest possible level. As we know, this reductionist approach leads to ever higher levels of equifinality and predictive uncertainty. On the other hand, simple, lumped and parsimonious models may be too simple to be realistic or representative of the dominant hydrological processes. In this commentary, a new model approach is proposed that tries to find the middle way between complex distributed and simple lumped modelling approaches. Here we try to find the right level of simplification while avoiding over-simplification. Paraphrasing Einstein, the maxim is: make a model as simple as possible, but not simpler than that. The approach presented is process based, but not physically based in the traditional sense. Instead, it is based on a conceptual representation of the dominant physical processes in certain key elements of the landscape. The essence of the approach is that the model structure is made dependent on a limited number of landscape classes in which the <span class="hlt">topography</span> is the main driver, but which can include geological, geomorphological or land-use classification. These classes are then represented by lumped conceptual models that act in parallel. The advantage of this approach over a fully distributed conceptualisation is that it retains maximum simplicity while taking into account observable landscape characteristics.</p> <div class="credits"> <p class="dwt_author">Savenije, H. H. G.</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-07-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">325</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2010HESS...14.2681S"> <span id="translatedtitle">HESS Opinions "<span class="hlt">Topography</span> driven conceptual modelling (FLEX-Topo)"</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Heterogeneity and complexity of hydrological processes offer substantial challenges to the hydrological modeller. Some hydrologists try to tackle this problem by introducing more and more detail in their models, or by setting-up more and more complicated models starting from basic principles at the smallest possible level. As we know, this reductionist approach leads to ever higher levels of equifinality and predictive uncertainty. On the other hand, simple, lumped and parsimonious models may be too simple to be realistic or representative of the dominant hydrological processes. In this commentary, a new approach is proposed that tries to find the middle way between complex distributed and simple lumped modelling approaches. Here we try to find the right level of simplification while avoiding over-simplification. Paraphrasing Einstein, the maxim is: make a model as simple as possible, but not simpler than that. The approach presented is process based, but not physically based in the traditional sense. Instead, it is based on a conceptual representation of the dominant physical processes in certain key elements of the landscape. The essence of the approach is that the model structure is made dependent on a limited number of landscape classes in which the <span class="hlt">topography</span> is the main driver, but which can include geological, geomorphological or land-use classification. These classes are then represented by lumped conceptual models that act in parallel. The advantage of this approach over a fully distributed conceptualisation is that it retains maximum simplicity while taking into account observable landscape characteristics.</p> <div class="credits"> <p class="dwt_author">Savenije, H. H. G.</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">326</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/10585521"> <span id="translatedtitle">Temporal cortex activation during speech recognition: an optical <span class="hlt">topography</span> study.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Cortical activity during speech recognition was examined using optical <span class="hlt">topography</span> (OT), a recently developed non-invasive technique. To assess relative changes in hemoglobin oxygenation, local changes in near-infrared light absorption were measured simultaneously from 44 points in both hemispheres. A dichotic listening paradigm was used in this experiment, in which target stimuli and non-target stimuli were presented to different ears. Subjects were asked to track targets and to press a button when targets shifted from one ear to the other. We compared three tasks: (i) a control task, in which a tone was used as the target; (ii) a repeat task, in which the target was one repeated sentence; (iii) a story task, in which the targets were continuous sentences of a story. The activity for the story task, compared with the repeat task, was localized in the left superior temporal cortex. Relative to the control task, we observed in this region a larger increase in oxyhemoglobin concentration and a decrease in deoxyhemoglobin concentration in the story task than those in the repeat task. These results suggest that the activity in the left temporal association area reflects the load of auditory, memory, and language information processing. PMID:10585521</p> <div class="credits"> <p class="dwt_author">Sato, H; Takeuchi, T; Sakai, K L</p> <p class="dwt_publisher"></p> <p class="publishDate">1999-12-17</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">327</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012espc.conf..428P"> <span id="translatedtitle"><span class="hlt">Topography</span> of Vesta from Dawn FC stereo images</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The Dawn mission has completed its Survey and High Altitude Mapping Orbit (HAMO) phases at Vesta and is currently in its Low Altitude Mapping Orbit (LAMO) [1]. From the Survey orbit (altitude ~2,700 km) the Dawn Framing Camera (FC) [2] acquired 1,179 clear filter images with a mean image resolution of 256 m/pixel whereas from the HAMO orbit (~700 km altitude) there are 2,674 clear filter images with a mean resolution of 63 m/pixel. In both mapping phases the surface was imaged several times under similar illumination conditions (Sun elevation and azimuth), but different viewing conditions (by tilting the spacecraft). This allows to analyze the images stereoscopically and to construct stereo topographic maps. The <span class="hlt">topography</span> is particularly important, because it is essential for derivation of physical properties of Vesta, precise ortho-image registration, mosaicking, and map generation of monochrome/color FC images and VIR images, quantitative geomorphologic analysis, and precise photometric analysis (from detailed local surface inclination).</p> <div class="credits"> <p class="dwt_author">Preusker, F.; Scholten, F.; Matz, K.-D.; Roatsch, T.; Jaumann, R.; Raymond, C. A.; Russell, C. T.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-09-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">328</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://pubs.usgs.gov/fs/2005/3068/report.pdf"> <span id="translatedtitle">Shuttle Radar <span class="hlt">Topography</span> Mission - New Products in 2005</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">In February 2000, the Shuttle Radar <span class="hlt">Topography</span> Mission (SRTM) successfully collected Interferometric C-Band Synthetic Aperture Radar data over 80 percent of the Earth's land surface, for most of the area between 60?N and 56?S latitude. NASA and the National Geospatial-Intelligence Agency (NGA), formerly known as the National Imagery and Mapping Agency (NIMA), co-sponsored the mission. NASA's Jet Propulsion Laboratory (JPL) performed preliminary processing of SRTM data and forwarded partially finished data directly to NGA for finishing by NGA contractors and subsequent monthly deliveries to the NGA Digital Products Data Warehouse (DPDW). All data products delivered by the contractors conform to NGA SRTM Data Products and NGA Digital Terrain Elevation Data? (DTED?) specifications. The DPDW ingests the SRTM data products, checks them for formatting errors, loads the public SRTM DTED? into the NGA data distribution system, and ships them to the U.S. Geological Survey (USGS) Center for Earth Resources Observation and Science (EROS). In addition to NGA's SRTM DTED? format, USGS EROS has reformatted the data into a non-proprietary, generic raster binary SRTM format that is readable by most remote sensing software packages. The SRTM format is also publicly available from USGS EROS.</p> <div class="credits"> <p class="dwt_author">Geological Survey (U.S.)</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">329</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2008AGUFM.G53A0629Y"> <span id="translatedtitle">SAR Image Coregistration Based on <span class="hlt">Topography</span> and Deformation</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">L-band repeat-pass InSAR has been getting scientists' attention for its penetration depth through dense vegetation, revealing the ground deformation under the canopy of forest. This makes it possible to achieve a good coverage of volcanic activities in tropical areas such as Hawaii, Galapagos, and Indonesia. Another advantage of L-band InSAR is its tolerance to a large baseline. The critical baseline scales with the wavelength, and practically a baseline of over 1 km often produces interferograms. However, the large baseline causes parallax in the presence of <span class="hlt">topography</span>, which appears as pixel shift between master and slave images that sometimes leads to a severe decorrelation. Using ALOS PALSAR data of Java Island, Indonesia, and intermediate files produced by ROI_PAC, we correct this parallax before forming an interferogram to improve the interferometric coherence. We also test an automatic implementation of the 'rubber sheeting" coregistration (e.g. Yun et al., GRL, 2007) for localized large deformation that cannot be explained by polynomial fitting.</p> <div class="credits"> <p class="dwt_author">Yun, S.; Kim, S.; Rosen, P.</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">330</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/22057798"> <span id="translatedtitle">Anatomical classification of the shape and <span class="hlt">topography</span> of the stomach.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">The aim of the study was to present the classification of anatomical variations of the stomach, based on the radiological and historical data. In years 2006-2010, 2,034 examinations of the upper digestive tract were performed. Normal stomach anatomy or different variations of the organ shape and/or <span class="hlt">topography</span> without any organic radiologically detectable gastric lesions were revealed in 568 and 821 cases, respectively. Five primary groups were established: abnormal position along longitudinal (I) and horizontal axis (II), as well as abnormal shape (III) and stomach connections (IV) or mixed forms (V). The first group contains abnormalities most commonly observed among examined patients such as stomach rotation and translocation to the chest cavity, including sliding, paraesophageal, mixed-form and upside-down hiatal diaphragmatic hernias, as well as short esophagus, and the other diaphragmatic hernias, that were not found in the evaluated population. The second group includes the stomach cascade. The third and fourth groups comprise developmental variations and organ malformations that were not observed in evaluated patients. The last group (V) encloses mixed forms that connect two or more previous variations. PMID:22057798</p> <div class="credits"> <p class="dwt_author">Burdan, Franciszek; Rozylo-Kalinowska, Ingrid; Szumilo, Justyna; Zinkiewicz, Krzysztof; Dworzanski, Wojciech; Krupski, Witold; Dabrowski, Andrzej</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-11-06</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">331</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://serc.carleton.edu/sp/mnstep/activities/35004.html"> <span id="translatedtitle">Investigating Karst <span class="hlt">topography</span> and its connection to SE Minnesota sinkholes and cave formations.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">This activity is a field investigation where students will be able to observe sinkholes located in the southeastern Minnesota area and a cave system in Forestville State Park which will assist them in defining Karst <span class="hlt">topography</span>.</p> <div class="credits"> <p class="dwt_author">Anne Feist Nrheg Public School New Richland, Mn</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">332</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013JGRE..118..908B"> <span id="translatedtitle">Convection-driven compaction as a possible origin of Enceladus's long wavelength <span class="hlt">topography</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The long wavelength surface <span class="hlt">topography</span> of Enceladus shows depressions about 1 km in depth and ˜102 km wide. One possible cause of this <span class="hlt">topography</span> is spatially variable amounts of compaction of an initially porous ice shell, driven by spatial variations in heat flux. Here, we show that the heat flux variations associated with convection in the shell can quantitatively match the observed features. We develop a simple model of viscous compaction that includes the effect of porosity on thermal conductivity, and find that an initial shell porosity of at least 20-25% is required to develop the observed <span class="hlt">topography</span> over ˜1 Ga. This mechanism produces topographic depressions, not rises, above convective upwellings, and does not generate detectable gravity anomalies. Unlike transient dynamic <span class="hlt">topography</span>, it can potentially leave a permanent record of ancient convective processes in the shallow lithospheres of icy satellites.</p> <div class="credits"> <p class="dwt_author">Besserer, J.; Nimmo, F.; Roberts, J. H.; Pappalardo, R. T.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-05-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">333</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2004OExpr..12.6278D"> <span id="translatedtitle">Study of the tear <span class="hlt">topography</span> dynamics using a lateral shearing interferometer</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The dynamics of the pre-corneal tear film <span class="hlt">topography</span> are studied on 21 subjects with a purpose-built lateral shearing interferometer. Interesting tear <span class="hlt">topography</span> features such as post-blink undulation, break-up, eyelid-produced bumps/ridges, bubbles and rough pre-contact lens tear surfaces were recorded. Using the calculated tear <span class="hlt">topography</span> maps, the effects of the tear dynamics in visual performance, refractive surgery and ophthalmic adaptive optics are discussed in terms of wavefront RMS. The potential of lateral shearing interferometry for clinical applications such as dry eye diagnosis and contact lens performance studies is illustrated by the recorded <span class="hlt">topography</span> features such as post-blink undulation, break-up, eyelid-produced bumps/ridges, bubbles and rough tear surfaces in front of contact lenses.</p> <div class="credits"> <p class="dwt_author">Dubra, Alfredo; Paterson, Carl; Dainty, Christopher</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">334</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1982BGeod..56...84R"> <span id="translatedtitle">Degree variances of the earth's potential, <span class="hlt">topography</span> and its isostatic compensation</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">A spherical harmonic expansion of the earth's gravitational potential and equivalent rock <span class="hlt">topography</span> to degree and order 180 is described. The potential implied by the <span class="hlt">topography</span> considered as uncompensated and with isostatic compensation has been computed. Good agreement with the observed potential field is found when the depth of compensation in the Airy theory is assumed to be 50 km. At the higher degrees the correlation coefficient between the potential expansion and the equivalent rock <span class="hlt">topography</span> is about 0.5. The Lachapelle equations for the topographic isostatic potential were tested using 1 x 1 deg equivalent rock <span class="hlt">topography</span>. The degree variances agree at the lower degrees but at degree 36 the Lachapelle results using 5 deg data underestimate the potential degree variances by about one-third.</p> <div class="credits"> <p class="dwt_author">Rapp, R. H.</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">335</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=207463"> <span id="translatedtitle">Modeling surface winds in mountainous catchments as a function of <span class="hlt">topography</span> and vegetation</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ars.usda.gov/services/TekTran.htm">Technology Transfer Automated Retrieval System (TEKTRAN)</a></p> <p class="result-summary">In order to develop accurate distributed hydrological models, spatially accurate meteorological forcing fields are required. In mountainous basins, elevation and <span class="hlt">topography</span> strongly influence temperature, precipitation, vapor pressure, and wind. At the watershed scale, temperature, precipitation, ...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">336</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=N7918722"> <span id="translatedtitle">Development of an X-Ray <span class="hlt">Topography</span> Equipment with Direct Display.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">The physical principles of the Lang technique for X-ray diffraction micrography were studied to determine the conditions necessary for <span class="hlt">topography</span> with direct display. A fluorescent screen was developed. Resolution of several micron m was obtained. A magni...</p> <div class="credits"> <p class="dwt_author">W. Hartmann</p> <p class="dwt_publisher"></p> <p class="publishDate">1977-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">337</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.springerlink.com/index/qjqrl7044p1147m3.pdf"> <span id="translatedtitle">A new, earth-based radar technique for the measurement of lunar <span class="hlt">topography</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Radio interferometry is a new technique for the measurement of the surface <span class="hlt">topography</span> of the Moon. Elevation data may be obtained directly without regard for unambiguously-identified features, for any lunar surface element that yields a recognizable radar echo.</p> <div class="credits"> <p class="dwt_author">S. H. Zisk</p> <p class="dwt_publisher"></p> <p class="publishDate">1972-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">338</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012LPI....43.1906W"> <span id="translatedtitle">Correction of Chandrayaan-1 M^3 Lunar Hyperspectral Image Data with Respect to Local <span class="hlt">Topography</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In this study we propose an empirical method to correct Chandrayaan-1 M³ hyperspectral image data with respect to the local <span class="hlt">topography</span> based on a digital elevation model (DEM) of high lateral resolution.</p> <div class="credits"> <p class="dwt_author">Wöhler, C.; Grumpe, A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-03-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">339</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=N20050165129"> <span id="translatedtitle">Extracting Compositional Variation from Themis Data for Features with Large <span class="hlt">Topography</span> on Mars Via Atmospheric Equalization.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">We have developed a means of equalizing the atmospheric signature in Mars Odyssey Thermal Emission Imaging System (THEMIS) infrared data over regions with large <span class="hlt">topography</span> such as the Valles Marineris (VM). This equalization allows for the analysis of com...</p> <div class="credits"> <p class="dwt_author">F. S. Anderson J. S. Drake V. E. Hamilton</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">340</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012PhDT........41O"> <span id="translatedtitle">Geodynamic Interpretations of Global <span class="hlt">Topography</span> and Gravity on Venus and Mars</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The <span class="hlt">topography</span> and gravity measurements from missions to Venus and Mars are among a few data available to constrain models of the interior structure and dynamics of these planets. These measurements reveal various intriguing features whose origins have generated debates in the planetary science community. On Venus, these include a high correlation between the long-wavelength <span class="hlt">topography</span> and the geoid. A common explanation is that the Venusian <span class="hlt">topography</span> is a result of dynamic uplift caused by mantle convection (dynamic <span class="hlt">topography</span>). Our analysis of convection models shows that in strongly temperature-dependent viscosity fluids, such as planetary mantles, the dynamic <span class="hlt">topography</span> is actually small. The lithosphere is close to a state of hydrostatic equilibrium (thermal isostasy) and the largest contributions to <span class="hlt">topography</span> and geoid anomalies come from the lithospheric thickness variations caused by sublithospheric convection. The Venusian <span class="hlt">topography</span> and geoid can be fully explained by the thermal isostasy associated with lithospheric thickness variations and the compositional isostasy associated with crustal thickness variations. A prominent feature on Mars is the hemispherical dichotomy where the southern highlands stand several kilometers elevated above the northern lowlands. One of the most common explanations for its formation is that the dichotomy formed as a result of a giant impact in the northern lowlands. We show that the impact could have been on the opposite side of the planet. A sufficiently large impact can melt the mantle to such extent that upon isostatic adjustment and crystallization of the melted part of the mantle it forms a region of high standing <span class="hlt">topography</span> (a megadome) instead of a crater. A topographic low forms antipodal to the impact (a megabasin).</p> <div class="credits"> <p class="dwt_author">Orth, Christopher P.</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_16");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' 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src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">341</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2003EAEJA.....4453K"> <span id="translatedtitle">Mapping of statistical characteristics of <span class="hlt">topography</span> on Mars with MOLA data</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Mars Orbiter Laser Altimeter (MOLA) produced a huge set of precise measurements of Mars surface elevation with uniform 0.3 km spacing along tracks. We use this data set to study statistical characteristics of the martian <span class="hlt">topography</span> at the scale from hundreds meters to tens of kilometers. Here we give a summary of our published and new results on mapping of statistical characteristics of <span class="hlt">topography</span> for the purposes of geomorphology and understanding of surface formation and alteration processes. The interquartile widths of the differential-slope- or curvature-frequency distributions are used as measures of the surface roughness at a series of scales. The Hurst exponent quantifies the scale dependence of roughness. The normalized median curvature characterizes the prevalence of concave or convex <span class="hlt">topography</span>. The normalized median differential slope being a measure of the asymmetry of the slope-frequency distribution, characterizes the north - south slope asymmetry. All maps clearly show the latitudinal trend. High-latitude areas (from the polar deposits edges to 60 deg latitude) are characterized by lower subkilometer-scale roughness, higher Hurst exponent and stronger prevalence of concave <span class="hlt">topography</span> than the equatorial zone (within 30 deg). The transitional zones (from 30 to 60 deg) are characterized by transitional values of roughness and Hurst exponent, by prevalence of convex <span class="hlt">topography</span>, and by noticeable slope asymmetry: the equator-facing slopes are steeper. The roughness and Hurst exponent also shows obvious correlation with geological units. The maps shows also some anomalous regions related to distribution of specific surficial deposits. For example, convex <span class="hlt">topography</span> prevails for giant polygons; eastern part of Daedalia Planum has anomalous prevalence of concave <span class="hlt">topography</span> and strong slope asymmetry; south-eastern part of Arabia Terra has slope asymmetry and prevalence of convex <span class="hlt">topography</span>; the hematite deposit has an anomalous signature in all maps.</p> <div class="credits"> <p class="dwt_author">Kreslavsky, M. A.; Head, J. W.</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-04-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">342</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/50797910"> <span id="translatedtitle">Statistical characteristic and parameter characterization of 3D surface micro-<span class="hlt">topography</span> on micro-EDM</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The characteristic of three-dimensional (3D) surface micro-<span class="hlt">topography</span> of micro-EDM plays an important role on the component function properties. In this paper, two types of 3D surface micro-<span class="hlt">topography</span>, which machined by micro-electrical discharge machining forming (micro-EDMF) and micro-wire electrical discharge machining (micro-WEDM), have been measured by the atomic force microscope (AFM) instrument after the surface data have been reshaped and denoised</p> <div class="credits"> <p class="dwt_author">Haijuan Ding; Libin Guo; Hai Cui</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">343</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1993GeoRL..20.1063B"> <span id="translatedtitle">The spectra of the <span class="hlt">topography</span> of the earth, Venus, and Mars</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">A spherical harmonic analysis is conducted for the <span class="hlt">topographies</span> of the terrestrial planets using extant data sets to the highest possible degree and order, with a view to establishing the decay of such spectra over a larger range of frequencies and ascertain the limit of validity of the data sets employed. The shape of power spectra is confirmed for the cases of the earth and for Venus; Mars <span class="hlt">topography</span> is still uncertain in many regions.</p> <div class="credits"> <p class="dwt_author">Balmino, G.</p> <p class="dwt_publisher"></p> <p class="publishDate">1993-06-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">344</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/40018000"> <span id="translatedtitle">Annual variation of sea surface height, dynamic <span class="hlt">topography</span> and circulation in the South China Sea</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">TOPEX\\/Poseidon satellite altimetry data from 1993 to 1999 were used to study mean annual variation of sea surface height anomaly\\u000a (SSHA) in the South China Sea (SCS) and to reproduce its climatological monthly surface dynamic <span class="hlt">topography</span> in conjunction\\u000a with historical hydrographic data. The characters and rules of seasonal evolution of the SCS dynamic <span class="hlt">topography</span> and its upper\\u000a circulation were then</p> <div class="credits"> <p class="dwt_author">Li Li; Jindian Xu; Chunsheng Jing; Risheng Wu; Xiaogang Guo</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">345</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/56246922"> <span id="translatedtitle">Effect of <span class="hlt">topography</span> on deposition from dilute pyroclastic density currents simulated by Ansys Fluent software</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Pyroclastic density currents are volcanic gas-particle flows that move along volcano flanks and over the neighboring <span class="hlt">topography</span>. Flow particle concentration can vary between two end members, concentrated and dilute. When a pyroclastic density current interacts with an uneven <span class="hlt">topography</span>, the flow-field variables (velocity, pressure, particle concentration) are drastically changed at the flow-substrate boundary. These changes may significantly affect the sedimentation</p> <div class="credits"> <p class="dwt_author">Domenico Maria Doronzo; Greg A. Valentine; Pierfrancesco Dellino; Marco D. de Tullio</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">346</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.usgs.gov/education/animations/karst97-536/guide.pdf"> <span id="translatedtitle">Karst <span class="hlt">Topography</span>: Teacher's Guide to Accompany Black and White and Color Paper Models</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">Using paper patterns, students are able to construct a model that depicts Karst <span class="hlt">topography</span>, including typical features such as caves, limestone bedrock, sink holes, and springs. The accompanying Teachers Guide provides extensive background information about the dissolutional processes that form caves. Information is also provided about unique animals found in caves and the importance of understanding Karst <span class="hlt">topography</span> in city planning and water resource issues.</p> <div class="credits"> <p class="dwt_author">Alpha, Tau; Galloway, John; Tinsley, John</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">347</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/53150400"> <span id="translatedtitle">Extreme sensitivity of the YORP effect to small-scale <span class="hlt">topography</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Radiation recoil (YORP) torques are shown to be extremely sensitive to small-scale surface <span class="hlt">topography</span>, using numerical simulations. Starting from a set of ``base objects'' representative of the near-Earth object population, random realizations of three types of small-scale <span class="hlt">topography</span> are added: Gaussian surface fluctuations, craters, and boulders. For each, the expected relative errors in the spin and obliquity components of the</p> <div class="credits"> <p class="dwt_author">Thomas S. Statler</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">348</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/27736571"> <span id="translatedtitle">Extreme sensitivity of the YORP effect to small-scale <span class="hlt">topography</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Radiation recoil (YORP) torques are shown to be extremely sensitive to small-scale surface <span class="hlt">topography</span>, using numerical simulations. Starting from a set of “base objects” representative of the near-Earth object population, random realizations of three types of small-scale <span class="hlt">topography</span> are added: Gaussian surface fluctuations, craters, and boulders. For each, the expected relative errors in the spin and obliquity components of the</p> <div class="credits"> <p class="dwt_author">Thomas S. Statler</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">349</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/53934893"> <span id="translatedtitle">Precise integrated <span class="hlt">topography</span> of Dokdo, East Sea, Korea, using LIDAR DEM and Multibeam echo sounding data</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">In this study, We created and analyzed Precise integrated <span class="hlt">topography</span> of Dokdo, East Sea, Korea, using land data that were collected by airborne LIDAR(Light Detection and Ranging) DEM(Digital Elevation Model) and seafloor bathymetry data by Multi-beam echo sounder. Airborne LIDAR DEM represent more detailed <span class="hlt">topography</span> of land than other DEM data. Composition of airborne LIDAR DEM and aerial photograph produced</p> <div class="credits"> <p class="dwt_author">C. Kim; H. Joo; E. Jeong; S. Lee; H. Kim</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">350</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2004AGUSM.H13B..06M"> <span id="translatedtitle">Watershed Residence Time and the Role of <span class="hlt">Topography</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In the past few decades, tracers have provided some of the most important insights into hydrological processes; from definition of groundwater and surface water age, to hydrograph source components, to descriptions of water flow pathways at the watershed scale. The age, or residence time of water is an integrated descriptor of watershed hydrology, revealing information about the storage, flow pathways and source of water in a single measure. Residence time offers a linkage to water quality, since the contact time in the subsurface largely controls stream chemical composition. While there has been tremendous recent interest in residence time estimation to characterize watersheds, there are relatively few studies that have quantified residence time at the watershed scale, and fewer still that have extended those results beyond single watersheds to larger landscape scales. We examined topographic controls on residence time for seven watersheds that range in basin area from 10 ha to 6200 ha and represent diverse geologic and geomorphic conditions in the western Cascade Mountains of Oregon. We found that baseflow mean residence time, estimated using stable isotope tracers, ranged from 0.8 to 3.6 years. Like in our previous work in other watersheds, there was no relationship with basin area. We then developed relationships between mean residence time and simple watershed terrain indices and found that mean residence time is highly correlated (r = 0.96) to the flow path distance and gradient. This illustrates that landscape organization (i.e., <span class="hlt">topography</span>), as opposed to watershed size controls transport. Results from this study may provide a framework for describing scale invariant transport across climatic and geologic conditions, whereby the internal form and structure of the basin defines the first order control on baseflow residence time. These findings may present new opportunities for watershed classification and regionalization based on seemingly simple internal topographic descriptors.</p> <div class="credits"> <p class="dwt_author">McGuire, K. J.; McDonnell, J. J.; Weiler, M.; Kendall, C.; McGlynn, B. L.; Welker, J. M.; Seibert, J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-05-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">351</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012DPS....4420710P"> <span id="translatedtitle">High Resolution <span class="hlt">Topography</span> for Thermal Modeling on Vesta</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">For more than a year, NASA's Dawn mission has been providing fascinating data on Vesta. Surface temperatures and thermal parameters are being derived using measurements by the Visual and Infrared Spectrometer (VIR) (Capria et al., 2012). However, the spatial distribution of temperatures is complex due to significant albedo variations over short distance scales and extensive cratering that generates shadows and complex surface features over small spatial scales. This results in VIR pixels that have sub-pixel variations in the temperature that are difficult to deconvolve. Here we report the benefits of using high-resolution topographic modeling when interpreting the thermal component of the VIR observations. Stereo-photoclinometry has been used for years to derive accurate shape models of planetary surfaces. It uses high-resolution images to determine both the surface reflectance and the incidence and emission angles for every pixel of every image. Using this data, we construct both the local surface <span class="hlt">topography</span> (known as maplets) as well as reflectance values for the Cornelia crater on Vesta (-9.7 Lat, 225 Lon), a fresh crater that has sharp relief and significant variations in albedo. Using this terrain model, we construct high-resolution, time-resolved insolation maps accounting for Bond albedo, incidence angle and shadowing effects of near-by features. From these maps, we calculate the temperature of the surface and subsurface using a 1-D thermal conduction model. This time-resolved model allows us to calculate the temperature at 3 times the spatial resolution for all regions of Cornelia crater at the time when VIR collected its observations. By combining the thermal flux for all the high-resolution points within a single VIR pixel element, we generate a thermal spectrum that accurately models the VIR data because they reflect slope inflections that are generated by sub-pixel temperature variations.</p> <div class="credits"> <p class="dwt_author">Palmer, Eric; Sykes, M. V.; Gaskell, R. W.; Li, J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-10-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">352</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3414911"> <span id="translatedtitle">PROSTATE CANCER <span class="hlt">TOPOGRAPHY</span> AND PATTERNS OF LYMPH NODE METASTASIS</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Pelvic lymph node (LN) metastasis is a well-recognized route of prostate cancer spread. However, the relationship between <span class="hlt">topography</span> and pathologic features of primary prostatic cancers and patterns of pelvic LN metastasis has not been well studied. We reviewed original slides of radical prostatectomies and pelvic LN dissections from 125 patients with LN metastasis and recorded total # of LN excised / laterality of positive LN, as well as localization, staging parameters, lymphovascular invasion and tumor volume of primary tumors. LN Quantity and Distribution 14.6 (mean) and 13 (median) LN were resected. 76 (61%), 33 (26%) and 16 (13%) cases had 1, 2 and > 2 positive LN, while 58, 44 and 20 cases had LN metastasis on the right (R), left (L), and bilaterally. Pathologic Features 86% (108/125) and 37% (46/125) demonstrated extraprostatic extension and seminal vesicle invasion, while 64% showed lymphovascular invasion. Mean and median total tumor volume was 6.39 and 3.92 cc, with ? 50% and ? 90% Gleason patterns 4/5 in 105 (84%) and 73 (58%) cases, respectively. Correlation with Dominant Tumor Location Dominant lesions on RP: 50 R lobe, 44 L lobe, 31 bilateral. 15/50 (30%) R lobe and 18/44 (41%) L lobe dominant tumors had LN metastasis on the contralateral side. Only 4% (5/125) of cases were associated with anterior dominant tumors. 30–40% of LN metastases occur contralateral to the dominant tumor. LN metastasis is overwhelmingly associated with high grade, high stage and large volume disease. LN positivity is rarely associated with anterior dominant tumors.</p> <div class="credits"> <p class="dwt_author">Tokuda, Yuji; Carlino, Lauren J.; Gopalan, Anuradha; Tickoo, Satish K.; Kaag, Matthew G.; Guillonneau, Bertrand; Eastham, James A.; Scher, Howard I.; Scardino, Peter T.; Reuter, Victor E.; Fine, Samson W.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">353</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/23613185"> <span id="translatedtitle">Mechanical forces regulate stem cell response to surface <span class="hlt">topography</span>.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">The interactions between bone tissue and orthopedic implants are strongly affected by mechanical forces at the bone-implant interface, but the interplay between surface <span class="hlt">topographies</span>, mechanical stimuli, and cell behavior is complex and not well understood yet. This study reports on the influence of mechanical stretch on human mesenchymal stem cells (hMSCs) attached to metallic substrates with different roughness. Controlled forces were applied to plasma membrane of hMSCs cultured on smooth and rough stainless steel surfaces using magnetic collagen-coated particles and an electromagnet system. Degree of phosphorylation of focal adhesion kinase (p-FAK) on the active form (Tyr-397), prostaglandin E2 (PGE2 ) and vascular endothelial growth factor (VEGF) levels increased on rough samples under static conditions. Cell viability and fibronectin production decreased on rough substrates, while hMSCs maturated to the osteoblastic lineage to a similar extent on both surfaces. PGE2 production and osteoprotegerin/receptor activator of nuclear factor kappa-B ligand ratio increased after force application on both surfaces, although to a greater extent on smooth substrates. p-FAK on Tyr-397 was induced fairly rapidly by mechanical stimulation on rough surfaces while cells cultured on smooth samples failed to activate this kinase in response to tensile forces. Mechanical forces enhanced VEGF secretion and reduced cell viability, fibronetin levels and osteoblastic maturation on smooth surfaces but not on rough samples. The magnetite beads model used in this study is well suited to characterize the response of hMSCs cultured on metallic surfaces to tensile forces and collected data suggest a mechanism whereby mechanotransduction driven by FAK is essential for stem cell growth and functioning on metallic substrates. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013. PMID:23613185</p> <div class="credits"> <p class="dwt_author">Saldaña, Laura; Crespo, Lara; Bensiamar, Fátima; Arruebo, Manuel; Vilaboa, Nuria</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-04-24</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">354</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2002EGSGA..27..635V"> <span id="translatedtitle">Bottom Ocean <span class="hlt">Topography</span> Estimation Improvement Using Altimetry and Depth Soundings</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The possibility of improving the estimation of bottom ocean <span class="hlt">topography</span> using altimetry-derived gravity data and shipborne depth soundings is investigated in two extended test regions. The integrated inversion method proposed by Knudsen and based on Parker's formula, for the relationship between gravity and bathymetry, is used to estimate new local bathymetry models. Initially, only gravity data are used and then gravity and shipborne depth soundings are combined in an iterative least- squares collocation procedure to produce the new depth models. The estimated models are validated in terms of the smoothing they provide to gravity field related quantities, used for geoid and gravity field approximation. Global models and shipborne soundings are also implemented in the validation procedure to investigate the improvement that the new models offer not only to gravity field modeling but also to the estimation of the bathymetry itself. For the depth estimation, the global multi-satellite altimetry-derived KMS99 gravity field and available depth soundings from the GEODAS database are used. The validation is carried out with the global JGP95E and Sandwell and Smith bathymetry models as well as with shipborne gravity data from BGI and altimetry sea surface heights from the ERS1 and GEOSAT Geodetic Mission altimetry. It is shown that, for both test areas, the new local bathymetry models manage to smooth the gravity field data by 15-25%, which is about 50% better compared to the global ones. Additionally, the implementation of both gravity and depth data provides a more realistic representation of the real bathymetry, and reduces the differences with the depth soundings and the global digital depth models (DDMs) to only 100-200 m, compared to 600-800 m for the gravity-only solutions.</p> <div class="credits"> <p class="dwt_author">Vergos, G. S.; Sideris, M. G.</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">355</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013JGRC..118..108S"> <span id="translatedtitle">Assessment of optimally filtered recent geodetic mean dynamic <span class="hlt">topographies</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary"><title type="main">AbstractRecent geoids from the Gravity Recovery and Climate Experiment (GRACE) and the Gravity field and steady state Ocean Circulation Explorer satellite mission (GOCE) contain useful short-scale information for the construction of a geodetic ocean mean dynamic <span class="hlt">topography</span> (MDT). The geodetic MDT is obtained from subtracting the geoid from a mean sea surface (MSS) as measured by satellite altimetry. A gainful use of the MDT and an adequate assessment needs an optimal filtering. This is accomplished here by defining a cutoff length scale dmax for the geoid and applying a Gaussian filter with half-width radius r on the MDT. A series of MDTs (GRACE, GOCE, and combined satellite-only (GOCO) solutions) is tested, using different sets of filter parameters dmax and r. Optimal global and regional dependent filter parameters are estimated. To find optimal parameters and to assess the resulting MDTs, the geostrophic surface currents induced by the filtered geodetic MDT are compared to corrected near-surface currents obtained from the Global Drifter Program (GDP). The global optimal cutoff degree and order (d/o) dmax (half-width radius r of the spatial Gaussian filter) is 160 (1.1°) for GRACE; 180 (1.1-1.2°) for 1st releases of GOCE (time- and space-wise methods) and GOCO models; and 210 (1.0 degree) for 2nd and 3rd releases of GOCE and GOCO models. The cutoff d/o is generally larger (smaller) and the filter length smaller (larger) for regions with strong, small-scale (slow, broad scale) currents. The smallest deviations from the drifter data are obtained with the GOCO03s geoid model, although deviations of other models are only slightly higher.</p> <div class="credits"> <p class="dwt_author">Siegismund, F.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">356</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1999PhDT.........2M"> <span id="translatedtitle">Lunar <span class="hlt">topography</span> from earth-based radar interferometric mapping</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">An incomplete knowledge of the <span class="hlt">topography</span> of the Moon has hindered the solution to several problems in lunar science and comparative planetology. The lack of elevation data over the polar regions and the generally sparse coverage in non-equatorial areas have restricted investigations related to the global shape of the Moon, impact cratering processes, and the possible presence of water ice at the lunar poles. Three-dimensional maps of the nearside and polar regions of the Moon can be obtained with an Earth-based radar interferometer. This technique allows surface heights to be accurately measured from the relative phase between radar echoes recorded at two separate receiving stations. The 70 m antenna and several 34 m stations of the Deep Space Network in California were configured as a radar interferometer for a sequence of observations in 1997. This experiment provided the first detailed topographic maps of the lunar polar regions, with a coverage of 300 x 1200 km at each pole. Elevation maps and radar imagery were also obtained for a 200 x 200 km region centered on Tycho Crater, the freshest large crater on the Moon. With a surface resolution of 150 m and a height resolution of 50 m or better, the radar maps represent significant improvements compared to existing lunar topographic data sets. The digital elevation model of Tycho Crater was used to determine the fundamental parameters of the crater's shape. The data revealed an asymmetry in floor elevations, rim heights, and wall slump zones, which may be related to an oblique nature for the impact. The topographic maps of the polar areas were used to verify previous estimates of global shape parameters for the Moon, and to locate regions which are in permanent shadow from solar illumination. The actual locations of the cold traps, potential reservoirs of ice deposits, are delineated on radar images of the lunar polar areas.</p> <div class="credits"> <p class="dwt_author">Margot, Jean-Luc C.</p> <p class="dwt_publisher"></p> <p class="publishDate">1999-09-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">357</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2003SPIE.4955..487Y"> <span id="translatedtitle">Optical fiber arrangement of optical <span class="hlt">topography</span> for spatial resolution improvement</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In medical instrumentation, optical <span class="hlt">topography</span> (OT) refers to the use of near-infrared spectroscopy for measuring brain function in systems. Arrays of optical fibers are attached to the scalps of subjects; infrared light is passed through the fibers, and changes in the reflections depict blood-volume changes in the cortex. In this study, the spatial resolution and locational accuracy of topographical images obtained by three arrangements of optical fibers was analyzed through simulation. Three arrangements, a "lattice arrangement" (LA), "double-density arrangement" (DA), and "quadruple density arrangement" (QA) were investigated. The density of spatial-sapling points is higher in the DA and QA than in the LA, i.e. the distance between sampling points for these arrangements were 21, 15 and 11 mm, respectively. The efficacy of these arrangements was evaluated. An adult head-structure phantom was prepared. The absorption coefficient in the phantom was varied to simulate brain activation in the cortex, and the resulting absorbance change (?OD) was thus obtained. The ‘activated" area in the overall measurement area was fixed and the ?OD at each of the sampling point in each arrangement was obtained. The resulting distributions of ?OD were spatially interpolated to obtain topographical images. The spatial resolution and locational accuracy was obtained for each of the images; the results indicated that the DA is the most efficacious of the three arrangements. An experimental DA-OT system was then built. Topographical images of motor-function activation obtained by this system and a commercial LA-based system were compared; the DA-OT system provided the higher spatial resolution.</p> <div class="credits"> <p class="dwt_author">Yamamoto, Tsuyoshi; Okada, Eiji; Kawaguchi, Fumio; Maki, Atsushi; Yamada, Yukio; Koizumi, Hideaki</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-07-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">358</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/3809962"> <span id="translatedtitle">Method-dependent number and <span class="hlt">topography</span> of coronary narrowings.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">A comparative gross and light microscopic study of the coronary arterial bed carried out on 95 selected male subjects aged 51-55 years, revealed that the number and <span class="hlt">topography</span> of narrowings (more than 50% luminal insufficiency) showed wide method-dependent variations. If only routine gross inspection of the major coronary arteries was performed (method 1) 52% of the subjects exhibited narrowings; if gross inspection was extended to the proximal segment of the first diagonal, first septal, left marginal, right marginal and posterior descending vessels, the proportion of subjects with coronary narrowings augmented to 61% (method 2); finally the use of the light microscopy to investigate vessels supplying the conduction system and terminal vessels (method 3) augmented this proportion to 73%. Conversely, we recorded the absence of narrowings encroaching more than 50% in 48% of the subjects with method 1, in 39% with method 2 and in only 27% with method 3. Using the second method we revealed in coronary branches 29 narrowings and with the third method 52 narrowings. From the 95 cases investigated 46 (48%) did not show narrowings in the major coronary arteries. Of these 46 cases, 17 (37%) exhibited narrowings in coronary branches. This would indicate that more than 1/3 of the subjects without greater than 50% narrowings in the major coronary arteries showed such lesions in the branches of these major coronary arteries. The results of this study demonstrated the necessity of gross and light microscopic examination of the whole coronary arterial bed in all attempts to offer a realistic anatomo-clinical correlation in ischemic heart disease: they also demonstrated that the atherosclerotic involvement of the coronary arterial bed is not limited to the segments grossly examined by each pathologist. PMID:3809962</p> <div class="credits"> <p class="dwt_author">Velican, C; Velican, D; Tâncu, I</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">359</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013EGUGA..1512898A"> <span id="translatedtitle">Spatial patterns in the evolution of Cenozoic dynamic <span class="hlt">topography</span> and its influence on the Antarctic continent</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Our knowledge of dynamic <span class="hlt">topography</span> in Antarctica remains in an infancy stage compared to other continents. We assess the space-time variability in dynamic <span class="hlt">topography</span> in Antarctica by analysing grids of global dynamic <span class="hlt">topography</span> in the Cenozoic (and late Cretaceous) based on the tomographic model S40RTS. Our model reveals that the Gamburtsev Province and Dronning Maud Land, two of the major nucleation sites for the East Antarctic Ice Sheet (EAIS) were ~500 m higher 60 Ma ago. The increased elevation may have facilitated ephemeral ice cap development in the early Cenozoic. Between ca 25 and 50 Ma the northern Wilkes Subglacial Basin was ca 200 m higher than today and a major increase in regional elevation (>600 m) occurred over the last 20-15 Ma over the northern and southern Victoria Land in the Transantarctic Mountains (TAM). The most prominent signal is observed over the Ross Sea Rift (RSR) where predicted Neogene dynamic <span class="hlt">topography</span> exceeds 1,000 m. The flow of warm mantle from the West Antarctic Rift System (WARS)may have driven these dynamic <span class="hlt">topography</span> effects over the TAM and RSR. However, we found that these effects are comparatively less significant over the Marie Byrd Land Dome and the interior of the WARS. If these contrasting dynamic <span class="hlt">topography</span> effects are included, then the predicted elevations of the Ross Sea Embayment ca 20 Ma ago are more similar to the interior of the WARS, with significant implications for the early development of the West Antarctic Ice Sheet.</p> <div class="credits"> <p class="dwt_author">Anderson, Lester; Ferraccioli, Fausto; Eagles, Graeme; Steinberger, Bernhard; Ritsema, Jeroen</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-04-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">360</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/17644361"> <span id="translatedtitle"><span class="hlt">Topography</span> of cortical and subcortical connections of the human pedunculopontine and subthalamic nuclei.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is the most common surgical therapy for Parkinson' s disease (PD). DBS of the pedunculopontine nucleus (PPN) is emerging as a promising surgical therapy for PD as well. In order to better characterize these nuclei in humans, we determined the anatomical connections of the PPN and STN and the <span class="hlt">topography</span> of these connections using probabilistic diffusion tractography. Diffusion tractography was carried out in eight healthy adult subjects using diffusion data acquired at 1.5 T MRI (60 directions, b=1000 s/mm(2), 2 x 2 x 2 mm(3) voxels). The major connections that we identified from single seed voxels within STN or PPN were present in at least half the subjects and the <span class="hlt">topography</span> of these connections within a 36-voxel region surrounding the initial seed voxel was then examined. Both the PPN and STN showed connections with the cortex, basal ganglia, cerebellum, and down the spinal cord, largely matching connections demonstrated in primates. The <span class="hlt">topography</span> of motor and associative brain areas in the human STN was strikingly similar to that shown in animals. PPN <span class="hlt">Topography</span> has not been extensively demonstrated in animals, but we showed significant <span class="hlt">topography</span> of cortical and subcortical connections in the human PPN. In addition to demonstrating the usefulness of PDT in determining the connections and <span class="hlt">topography</span> of small grey matter structures in vivo, these results allow for inference of optimal DBS target locations and add to our understanding of the role of these nuclei in PD. PMID:17644361</p> <div class="credits"> <p class="dwt_author">Aravamuthan, B R; Muthusamy, K A; Stein, J F; Aziz, T Z; Johansen-Berg, H</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-06-07</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_17");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return 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class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_18");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' href="#">4</a> <a onClick='return showDiv("page_5");' href="#">5</a> <a onClick='return showDiv("page_6");' href="#">6</a> <a onClick='return showDiv("page_7");' href="#">7</a> <a onClick='return showDiv("page_8");' href="#">8</a> <a onClick='return 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title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">361</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3538343"> <span id="translatedtitle">Insect Wing Membrane <span class="hlt">Topography</span> Is Determined by the Dorsal Wing Epithelium</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">The Drosophila wing consists of a transparent wing membrane supported by a network of wing veins. Previously, we have shown that the wing membrane cuticle is not flat but is organized into ridges that are the equivalent of one wing epithelial cell in width and multiple cells in length. These cuticle ridges have an anteroposterior orientation in the anterior wing and a proximodistal orientation in the posterior wing. The precise <span class="hlt">topography</span> of the wing membrane is remarkable because it is a fusion of two independent cuticle contributions from the dorsal and ventral wing epithelia. Here, through morphological and genetic studies, we show that it is the dorsal wing epithelium that determines wing membrane <span class="hlt">topography</span>. Specifically, we find that wing hair location and membrane <span class="hlt">topography</span> are coordinated on the dorsal, but not ventral, surface of the wing. In addition, we find that altering Frizzled Planar Cell Polarity (i.e., Fz PCP) signaling in the dorsal wing epithelium alone changes the membrane <span class="hlt">topography</span> of both dorsal and ventral wing surfaces. We also examined the wing morphology of two model Hymenopterans, the honeybee Apis mellifera and the parasitic wasp Nasonia vitripennis. In both cases, wing hair location and wing membrane <span class="hlt">topography</span> are coordinated on the dorsal, but not ventral, wing surface, suggesting that the dorsal wing epithelium also controls wing <span class="hlt">topography</span> in these species. Because phylogenomic studies have identified the Hymenotera as basal within the Endopterygota family tree, these findings suggest that this is a primitive insect character.</p> <div class="credits"> <p class="dwt_author">Belalcazar, Andrea D.; Doyle, Kristy; Hogan, Justin; Neff, David; Collier, Simon</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">362</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2011AGUFMEP31A0794Y"> <span id="translatedtitle">Monitoring of desert dune <span class="hlt">topography</span> by multi angle sensors</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Nowadays, the sandy desert is rapidly expanding world widely and results in a lot of risks in the socio-econimical aspects as well as the anthropogenic activities. For example, the increasing occurrences of mineral dust storm which presumably originated from the sandy deserts in northwest China become a serious threat in human activities as well as public health over Far East Asian area as the interpretation by the MODIS analysis (Zhang et al., 2007) and the particle trajectory simulation with HYSPLYT (HYbrid Single-Particle Lagrangian Integrated Trajectory) (Kim et al., 2011) identified. Since the sand dune activity has been recognized as an essential indicator of the progressive desertification, it is important to establish the monitoring method for the variations of topographic properties by the dune activities such as local roughness. Thus it will provide the crucial data about the extent and the transition of sandy desert. For example, it is well known the aerodynamic roughness lengths Zo which can be driven from the specialized sensor such as POLDER (POLarization and Directionality of the Earth's Reflectances) is essential to understand desert dune characteristics. However, for the multi temporal observation of dune fields, the availability of data set to extract Zo is limited. Therefore, we employed MISR (Multi angle imaging Spectro Radiometer) image sequence to extract multi angle topographic parameters such as NDAI (Normalized Difference Angular Index) or the variation of radiance with the viewing geometry which are representing the characteristics of target desert <span class="hlt">topography</span> instead of Zo. In our approach, NDAI were expanded to the all viewing angles and then compared over the target sandy desert and the surrounding land covers. It showed very strong consistencies according to the land cover type and especially over the dynamic dune fields. On the other hands, the variation of NDAIs of sandy desert combining with the metrological observations were examined and showed a correlation between the intensities sand dune activities and the surface wind conditions. In conclusion, we proved that the trace of the sandy desert boundaries for long observation period is feasible with the multi angle orbital sensor observation by investigating the expanded NDAIs from various sample sand dune fields. However, it is quite uncertain whether the consistency of MISR NDAIs over sandy deserts originated from the aeolian micro structures, the reflectance of sand or the aspect angle of dune morphology. Therefore, in the next stage, the local roughness properties extracted from MISR data analysis will be compared with the topographic information from high resolution stereo satellite imagery such as ALOS PRISM (Panchromatic Remote-sensing Instrument for Stereo Mapping). Consequently it will correctly evaluate the suitability of multi angle observation parameters as a dune activity indicator.</p> <div class="credits"> <p class="dwt_author">Yun, J.; Kim, J.; Choi, Y.; Yun, H.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">363</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013EGUGA..1510302M"> <span id="translatedtitle">Tracing tectonics in <span class="hlt">topography</span> in the Bükk Mountains, NE Hungary</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Relief, as we see it today, is shaped and formed by numerous processes the dominance of which is determined by the geographical location of the area the relief belongs to. In areas, however, where solid rocks of distinct tectonic history with clearly definable deformation elements are close to the surface the structural geological character of the subsurface formations fundamentally determine the <span class="hlt">topography</span>. Location of the most spectacular peaks, shape of the ridges between them, location and orientation of valleys and even the direction of smaller valley sections are determined by the structural features and conditions of the underlying geology. The authors carried out structural geological analyses in an area (Bükk Mountains, NE Hungary) showing a relatively diverse geology composed of Triassic carbonates, Triassic and Jurassic siliciclastic sediments (foliated sandstone, shales) and Triassic igneous rocks (metamorphosed basalt, andesite and rhyolite). Structural elements of both brittle and ductile deformations have been identified and measured in the form of frontal thrusts, transverse (tension) joints, conjugated lithoclases, cleavage planes, fold limbs and fold axes. Based on the results, the orientation of two major stress fields acting in several phases (mostly in the Cretaceous) have been identified as responsible for the production of the major structural elements. Observing the interesting orientation of valleys, the strange form of ridges and the appearance of peculiar landforms both in field and on topographic maps / satellite images made the authors curious to find their explanation. As a result, the orientation of valleys was correlated to the orientation of the prevailing brittle structural elements in a model area within the Bükk Mountains. Even the smaller valley sections were correlated to the joint directions in the model area. Direction of the lines of the ridges was also correlated to the structural features of the model area. Strong correlation between the morphological and structural features was detected even in underground morphological forms as the direction of the passages of caves in the model area also matched the direction of brittle structural elements. Furthermore, the appearance of unusual relief forms could be explained by the occurrence of special structural features produced by the specific interaction of the two dominant stress fields and the resultant superposed structural elements. The results enable us to extend the structural analysis and re-construction established for a model area over the surrounding areas without further detailed structural analyses in case a generally similar geological setting and tectonic history can be assumed.</p> <div class="credits"> <p class="dwt_author">McIntosh, Richard William; Bódi, Erika; Kozák, Miklós; Buday, Tamás</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-04-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">364</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013EGUGA..1511143B"> <span id="translatedtitle">Jet Formation Mechanisms in the presence of <span class="hlt">Topography</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Despite over 35 years of discussion, there still remain a range of theories describing the formation of jets on a beta plane. One such theory, first proposed by Rhines (1975), is that jets form as a result of an inverse cascade of energy that is halted by the excitation of Rossby waves. We present the results of an investigation in which we attempt to apply this theory to the case of tilted jets forming over a uniform slope in bottom <span class="hlt">topography</span> in a quasi-geostrophic, two-layer, doubly periodic model. The forms of the Rossby wave frequencies of this system depend on the Rossby deformation radius, and have two limits: a shortwave limit in which the two frequencies are the equivalent layer-wise frequencies, and orientated with the layer-wise PV gradients; and a longwave limit in which the two frequencies are barotropic- and baroclinic-like, and orientated with the barotropic PV gradient. Freely decaying simulations of the system show that the anisotropy of the frequencies successfully predicts the orientation of the jets that form, which are found to be decoupled and follow layer-wise PV gradients in the shortwave limit, and to be coupled and follow the barotropic PV gradient in the longwave limit. Introducing shear and bottom friction does not change the qualitative form of the Rossby wave frequencies, but due to the forcing by baroclinic instability occurring close to the deformation radius, all such quasi-equilibrated simulations are in the longwave limit and jets follow the barotropic PV gradient. However, only some simulations demonstrate the predicted inverse cascade and associated cascade barrier. Other simulations do not have a well developed inverse cascade, and yet still show jet formation. Previous studies have also shown that significant non-local transfers of energy occur in quasi-geostrophic systems with jets, which suggests a richer picture of jet formation. We thus propose that Rossby waves provide a barrier to further energy transfer, and their anisotropy predicts the jet orientation, but that the energy transfer does not necessarily take the form of an inverse cascade. This work is a significant step towards understanding the formation of jets in quasi-geostrophic turbulence, and is also of relevance to the regions of the ocean where strong non-zonal jets are present.</p> <div class="credits"> <p class="dwt_author">Boland, Emma; Haynes, Peter; Shuckburgh, Emily</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-04-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">365</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2007AGUFM.T21B0599A"> <span id="translatedtitle">French Polynesia Hotspot Swells Explained By Dynamic <span class="hlt">Topography</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Situated on the South Pacific Superswell, French Polynesia is a region characterized by numerous geophysical anomalies among which a high volcanism concentration. Seven hotspots are required to explain the observed chains, volcanism ages and geochemical trends. Many open questions still remain on the origin of these hotspot chains: are they created by passive uplift of magma due to discontinuities in the structure of the lithosphere or by the ascent of mantle plumes? In this case, at which depth do these plumes initiate in the mantle? Many geophysical observations (bathymetry, gravity, magnetism, volcanism ages..) are used to understand the unique phenomenon occurring on this region. The most useful information may come from tomography models since they provide a 3D view of the mantle. Until recently, the tomography models over the region were quite inaccurate because of the sparse location of the seismic stations. The deployment of two new seismic stations networks (BBOBS and temporary island stations) has lately remedied this failing. The resulting tomography model obtained through the inversion of Rayleigh waves provides the most accurate view of the shallowest part of the mantle (depths ? 240 km) beneath French Polynesia. Indeed, for the first time the accuracy of a tomography model is good enough to provide information about plume phenomenology in this complex region. In order to quantify the plumes effect on the seafloor, we compute the dynamic <span class="hlt">topography</span> through an instantaneous flow model. The general trend of the observed depths anomalies (highs and lows) is well recovered. For example the amplitude, location and extension of the swells associated with the Society, Macdonald and Rarotonga are accurately described by the dynamic model. We also find that dynamic uplift is associated with the Tuamotu archipelago which means that a part of the observed swell is due to the present day action of plumes. Since no volcanism ages are available over this chain, this new information may be quite important in understanding the archipelago origin. Another interesting result is that Arago, which is supposed to be an active hotspot along the Cook-Austral chain is situated on a bathymetric low which is well recovered by the dynamic model. Since this region is associated with downwelling flows, this makes us question its hotspot origin.</p> <div class="credits"> <p class="dwt_author">Adam, C.; Yoshida, M.; Isse, T.; Suetsugu, D.; Shiobara, H.; Sugioka, H.; Kanazawa, T.; Fukao, Y.; Barruol, G.</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">366</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2011AGUFM.T24C..03Y"> <span id="translatedtitle">The Impact of Drainage Reorganization on Cenozoic <span class="hlt">Topography</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Landscape evolution and the resulting sedimentary deposits are controlled by the development and organization of drainage basins. As a landscape evolves within a climatic and tectonic environment, drainage reorganization events can occur, where one river basin grows at the expense of another. The added discharge downstream of a river capture location will generate a transient topographic response. The records of these events are preserved the sedimentary record and modern <span class="hlt">topography</span>. Drainage reorganization has been proposed to occur in a number of major drainage systems around the world including the Colorado, Rhine, Snake, Yellow, Yangtze, Indus, and Zambezi rivers as well as a number of smaller rivers. Yet little work has focused on quantifying the topographic and erosional consequence of such events. Here we propose a simple model that quantifies the impacts of drainage capture on the evolution of a drainage basin. The model is based on the inverse slope-contributing drainage area relationship observed in rivers throughout the world and describes the expected river elevation change as drainage area is added (and therefore slopes lowered) by a capture event. Furthermore, we develop a numerical model of drainage capture that quantifies the transience of erosion and sediment production based on a shear stress dependent fluvial incision and sediment transport model. Our focus here is on quantifying the impact of capture of the Rhine/Aare river system (~45,000 km2) during the late Pliocene/early Pleistocene. Our models suggest 500-800 m of river elevation change (lowering profiles) occurred over short time periods (less than a million years), contributing as much as 0.4 mm/yr of erosion to the Alpine foreland and Swiss Alps when averaged over the last few million years. The predicted incision magnitudes are consistent with incision measured from the elevation of Pliocene and early Pleistocene river gravels, suggesting that the majority of incision across northern Switzerland can be explained by drainage reorganization. We also present estimates of incision magnitudes for other capture events around the world, and show that the erosion impacts of drainage reorganization events are capable of producing significant pulses of sediments out of the basin. This has implications for the interpretation of sedimentary deposits and their relation to tectonic and climatic changes.</p> <div class="credits"> <p class="dwt_author">Yanites, B. J.; Ehlers, T. A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">367</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2010ESSD....2..261T"> <span id="translatedtitle">A consistent data set of Antarctic ice sheet <span class="hlt">topography</span>, cavity geometry, and global bathymetry</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Sub-ice shelf circulation and freezing/melting rates in ocean general circulation models depend critically on an accurate and consistent representation of cavity geometry. Existing global or pan-Antarctic <span class="hlt">topography</span> data sets have turned out to contain various inconsistencies and inaccuracies. The goal of this work is to compile independent regional surveys and maps into a global data set. We use the S-2004 global 1-min bathymetry as the backbone and add an improved version of the BEDMAP <span class="hlt">topography</span> (ALBMAP bedrock <span class="hlt">topography</span>) for an area that roughly coincides with the Antarctic continental shelf. The position of the merging line is individually chosen in different sectors in order to capture the best of both data sets. High-resolution gridded data for ice shelf <span class="hlt">topography</span> and cavity geometry of the Amery, Fimbul, Filchner-Ronne, Larsen C and George VI Ice Shelves, and for Pine Island Glacier are carefully merged into the ambient ice and ocean <span class="hlt">topographies</span>. Multibeam survey data for bathymetry in the former Larsen B cavity and the southeastern Bellingshausen Sea have been obtained from the data centers of Alfred Wegener Institute (AWI), British Antarctic Survey (BAS) and Lamont-Doherty Earth Observatory (LDEO), gridded, and blended into the existing bathymetry map. The resulting global 1-min Refined <span class="hlt">Topography</span> data set (RTopo-1) contains self-consistent maps for upper and lower ice surface heights, bedrock <span class="hlt">topography</span>, and surface type (open ocean, grounded ice, floating ice, bare land surface). The data set is available in NetCDF format from the PANGAEA database at <a href="http://dx.doi.org/10.1594/pangaea.741917" target="_blank">doi:10.1594/pangaea.741917</a>.</p> <div class="credits"> <p class="dwt_author">Timmermann, R.; Le Brocq, A.; Deen, T.; Domack, E.; Dutrieux, P.; Galton-Fenzi, B.; Hellmer, H.; Humbert, A.; Jansen, D.; Jenkins, A.; Lambrecht, A.; Makinson, K.; Niederjasper, F.; Nitsche, F.; Nøst, O. A.; Smedsrud, L. H.; Smith, W. H. F.</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">368</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013EnMan..52..821W"> <span id="translatedtitle">Determining Relative Contributions of Vegetation and <span class="hlt">Topography</span> to Burn Severity from LANDSAT Imagery</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Fire is a dominant process in boreal forest landscapes and creates a spatial patch mosaic with different burn severities and age classes. Quantifying effects of vegetation and <span class="hlt">topography</span> on burn severity provides a scientific basis on which forest fire management plans are developed to reduce catastrophic fires. However, the relative contribution of vegetation and <span class="hlt">topography</span> to burn severity is highly debated especially under extreme weather conditions. In this study, we hypothesized that relationships of vegetation and <span class="hlt">topography</span> to burn severity vary with fire size. We examined this hypothesis in a boreal forest landscape of northeastern China by computing the burn severity of 24 fire patches as the difference between the pre- and post-fire Normalized Difference Vegetation Index obtained from two Landsat TM images. The vegetation and <span class="hlt">topography</span> to burn severity relationships were evaluated at three fire-size levels of small (<100 ha, n = 12), moderate (100-1,000 ha, n = 9), and large (>1,000 ha, n = 3). Our results showed that vegetation and <span class="hlt">topography</span> to burn severity relationships were fire-size-dependent. The burn severity of small fires was primary controlled by vegetation conditions (e.g., understory cover), and the burn severity of large fires was strongly influenced by topographic conditions (e.g., elevation). For moderate fires, the relationships were complex and indistinguishable. Our results also indicated that the pattern trends of relative importance for both vegetation and <span class="hlt">topography</span> factors were not dependent on fire size. Our study can help managers to design fire management plans according to vegetation characteristics that are found important in controlling burn severity and prioritize management locations based on the relative importance of vegetation and <span class="hlt">topography</span>.</p> <div class="credits"> <p class="dwt_author">Wu, Zhiwei; He, Hong S.; Liang, Yu; Cai, Longyan; Lewis, Bernard J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-10-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">369</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/23887487"> <span id="translatedtitle">Determining Relative Contributions of Vegetation and <span class="hlt">Topography</span> to Burn Severity from LANDSAT Imagery.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Fire is a dominant process in boreal forest landscapes and creates a spatial patch mosaic with different burn severities and age classes. Quantifying effects of vegetation and <span class="hlt">topography</span> on burn severity provides a scientific basis on which forest fire management plans are developed to reduce catastrophic fires. However, the relative contribution of vegetation and <span class="hlt">topography</span> to burn severity is highly debated especially under extreme weather conditions. In this study, we hypothesized that relationships of vegetation and <span class="hlt">topography</span> to burn severity vary with fire size. We examined this hypothesis in a boreal forest landscape of northeastern China by computing the burn severity of 24 fire patches as the difference between the pre- and post-fire Normalized Difference Vegetation Index obtained from two Landsat TM images. The vegetation and <span class="hlt">topography</span> to burn severity relationships were evaluated at three fire-size levels of small (<100 ha, n = 12), moderate (100-1,000 ha, n = 9), and large (>1,000 ha, n = 3). Our results showed that vegetation and <span class="hlt">topography</span> to burn severity relationships were fire-size-dependent. The burn severity of small fires was primary controlled by vegetation conditions (e.g., understory cover), and the burn severity of large fires was strongly influenced by topographic conditions (e.g., elevation). For moderate fires, the relationships were complex and indistinguishable. Our results also indicated that the pattern trends of relative importance for both vegetation and <span class="hlt">topography</span> factors were not dependent on fire size. Our study can help managers to design fire management plans according to vegetation characteristics that are found important in controlling burn severity and prioritize management locations based on the relative importance of vegetation and <span class="hlt">topography</span>. PMID:23887487</p> <div class="credits"> <p class="dwt_author">Wu, Zhiwei; He, Hong S; Liang, Yu; Cai, Longyan; Lewis, Bernard J</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-07-26</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">370</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/51887084"> <span id="translatedtitle">The relationship between MOLA northern hemisphere <span class="hlt">topography</span> and the 6.1-mbar atmospheric pressure surface of Mars</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">To assist in targeting of landers and to enable comparison of new elevation data to previous <span class="hlt">topography</span> models, we have re-determined the position of the 6.1-mbar atmospheric pressure surface on Mars with respect to surface <span class="hlt">topography</span> from the Mars Orbiter Laser Altimeter (MOLA). The 6.1-mbar surface lies, on average, 1600 m below the geoid-defined zero level of MOLA <span class="hlt">topography</span>, which</p> <div class="credits"> <p class="dwt_author">David E. Smith; Maria T. Zuber</p> <p class="dwt_publisher"></p> <p class="publishDate">1998-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">371</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2009AGUFM.S41E..05H"> <span id="translatedtitle">A Study of Frequency-Dependent Seismic Wave Amplifications due to <span class="hlt">Topography</span> Effects</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We present a study of the effects of free surface <span class="hlt">topography</span> on the amplification of seismic waves. To this end we investigate a parameter space in which we systematically consider various frequencies of the incident wave, increasing roughness of the <span class="hlt">topography</span>, and different spatial resolutions of the discrete <span class="hlt">topography</span> model. We compare the ground motion at different topographic features, such as mountain peaks, elongated ridges, or valley floors in order to derive crest-to-base amplification factors of peak ground velocities and rotations. The study is mainly based on numerical simulations using the Discontinuous Galerkin method of high-order space and time accuracy that allows for an precise incorporation of real <span class="hlt">topography</span> models given by high-resolution digital elevation models. Furthermore, we chose an area of investigation in southern Germany, where observational data is available to compare our numerical results with real measurements. Our results show at under which circumstances the incorporation of <span class="hlt">topography</span> has important implications on the seismic wave field. We show possible consequences to consider in seismic hazard assessment and earthquake engineering.</p> <div class="credits"> <p class="dwt_author">Hermann, V. K.; Kaeser, M.; Wassermann, J. M.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">372</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012EGUGA..14.4322S"> <span id="translatedtitle">Geophysical investigations of the East Greenland Caledonides using receiver functions, gravity and <span class="hlt">topography</span> data</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The present-day <span class="hlt">topography</span> and crustal structure of the East Greenland Caledonides are a product of various events, including the Caledonian orogeny, lithospheric extensional collapse, continental breakup and erosional processes. The topographic elevation appears high in this region, still after considering erosional uplift, connected to fjord formation. This apparent longevity of <span class="hlt">topography</span> remains a matter of discussion. In this context the relationship of <span class="hlt">topography</span> to crustal thickness and isostasy is a central aspect. Erosion and possible subcrustal processes are of further importance. Shallow crustal structures related to extensional basin formation, a lower crustal high velocity layer and a crustal root have to be considered. A profile of 11 temporary broadband stations was deployed and maintained by Aarhus University for a period of 2 years (2009 - 2011). The approximately 270 km long Ella Ø array crosses the East Greenland Caledonides from the ice sheet to the coastline at about 73° north. The data are of high quality. Initial Receiver Function results are interpreted together with corresponding gravity and <span class="hlt">topography</span> data and additionally compared with synthetic data, using velocity models from published wide-angle seismic studies in the area. The evolution of the East Greenland and Norwegian Caledonides at the conjugated margins may be closely connected. A comparison with a similar study in Norway will give insight to what extend <span class="hlt">topography</span>, crustal and upper mantle structures on both sides correlate and display similarities as well as a common evolution and tectonic origin.</p> <div class="credits"> <p class="dwt_author">Schiffer, C.; Jacobsen, B. H.; Balling, N.; Nielsen, S. B.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-04-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">373</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012ApSS..258.7082Q"> <span id="translatedtitle">Hybrid dimension based modeling of part surface <span class="hlt">topography</span> and identification of its characteristic parameters</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Since the complete description of complex part surface is difficult to achieve using the existing integral dimensional or fractal dimensional approaches, the novel concept of hybrid dimension and its modeling method of part surface <span class="hlt">topography</span> are proposed in this paper. The hybrid dimensional model of part surface <span class="hlt">topography</span> is established based on the deflection method of surface correlation coefficient, which associates the integral dimensional and fractal dimensional surface <span class="hlt">topographies</span>. Superimposing the normalized fractal dimensional surface altitude field on the B-spline surface, the hybrid dimensional model can express the integral dimensional information of part surface in macro level, and the fractal dimensional detail in micro level. And the correlation of part surface <span class="hlt">topographies</span> among different scales and different dimensions is established by the Hybrid Dimensional Surface Correlation Coefficient. Moreover, the characteristic parameter identification method for the hybrid dimensional model of part surface <span class="hlt">topography</span> is proposed. The component information of integral dimension and fractal dimension is separated and extracted by wavelet analysis, and hybrid dimensional characteristic parameters are identified by the generalized surface structure function method and the roughness mapping method. Finally, the proposed method is applied to design and manufacture of turbo expander.</p> <div class="credits"> <p class="dwt_author">Qiu, Chan; Liu, Zhenyu; Bu, Wanghui; Tan, Jianrong</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-07-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">374</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2010AGUFM.T23C2308M"> <span id="translatedtitle">Neogene <span class="hlt">Topography</span> And Precipitation Patterns Of The Central Anatolian Plateau</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Long-term stable isotope records of terrestrial environments represent increasingly important tools for tectonic, paleoaltimetric, and paleoclimatic reconstructions within continental interiors. A rapidly growing number of studies within the Earth’s major mountain ranges demonstrates that the growth of <span class="hlt">topography</span> and orogenic plateaus profoundly influences local, regional, and hemispheric climate and hence precipitation patterns while regional surface uplift patterns are intimately linked to plate-scale geodynamic processes. In contrast, such records are almost absent for the Near East and the Turkish-Iranian plateau, an important topographic element in the Alpine-Himalayan chain and an area most likely to be strongly affected by future climate change and water scarcity. Our objective is to assess the role of orographic factors that have governed the distribution (and isotopic composition) of precipitation across the central Anatolian plateau (CAP, Turkey) from the Neogene to recent. Such data are fundamental for our understanding of the geodynamic and sedimentary history of orogenic plateaus in general and for the role of surface uplift along the plateau margins in the Pontide and Tauride mountains. We present oxygen, carbon, and hydrogen isotope data from Neogene-to-recent fluvio-lacustrine and pedogenic environments, stream and lake waters of the CAP with the ultimate aim of reconstructing past precipitation changes, plateau aridification and ideally Neogene surface uplift histories. Our approach is to cross-calibrate modern patterns of isotopes (oxygen and hydrogen) in precipitation with pedogenic carbonate oxygen and carbon isotope data across topographic barriers that today strongly control the distribution of rainfall along the plateau margins and within the plateau interior. We then compare these patterns with Miocene-to-Pleistocene lacustrine and pedogenic records to assess a) the role of late Neogene (ca. 8-0 Ma) surface uplift in the Taurus mountains and the importance of rain shadow development in the lee of the plateau margins. Based on ca. 350 hydrogen and oxygen isotope data from modern streams and rivers we document the orographic effect of the southern plateau margin onto the hydrogen and oxygen isotopes in precipitation with apparent oxygen isotope lapse rates that fall within the global average (0.2-0.4 ‰/100 m) and a leeward decrease in the oxygen isotope ratios of ca. 3-4 ‰ compared to sea level. Miocene-to-recent lacustrine and pedogenic carbon and oxygen isotope profiles from the southern plateau margin into the plateau interior (Ermenek, Ankara, Cankiri, Kastamonu basins) document that to first-order similar-to-modern lake isotope records characterize the late Neogene with strongly evaporative lake systems dominant in the Pliocene. Based on our current long-term stable isotope data we preliminarily conclude that surface uplift of the Central Anatolian Plateau occurred at different rates and magnitudes along the Taurus Mountains which places indirect constraints on plate boundary and mantle dynamics in the Eastern Mediterranean region.</p> <div class="credits"> <p class="dwt_author">Mulch, A.; Mikes, T.; Schemmel, F.; Rojay, B.</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">375</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2011AGUFMEP23B0741L"> <span id="translatedtitle">Small-Scale Gopher and Plant Activity Organizes a Simulated Landscape Into Mound-Pool <span class="hlt">Topography</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The Mima-mound-and-vernal-pool <span class="hlt">topography</span> of California is rich in endemic species, but we do not know how this unusual environment is created or maintained. Fossorial rodents have been observed to move soil upwards at annual rates sufficient to maintain the mounds despite erosion, but there is no tested explanation of this behavior. We propose that the mounds are an emergent effect of small-scale (10 cm, 1 day) interactions between <span class="hlt">topography</span>, hydrology, plant growth, and rodent burrowing. A cellular automata simulation of these both generates and maintains mound-pool <span class="hlt">topography</span> with minimal dependence on initial conditions, and can also describe mound morphogenesis on slopes, where observed mound geometry is distinct from that on level ground.</p> <div class="credits"> <p class="dwt_author">Lewis, C. P.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">376</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2009SPIE.7273E.121R"> <span id="translatedtitle">Simulation of optical lithography in the presence of <span class="hlt">topography</span> and spin-coated films</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Experimental results on etched silicon wafers show that after two consecutive spin-coat processes the upper material surface achieves near planar flatness. This was observed for three separate dual layer BARC systems and the case of photoresist over a single layer BARC. The wafer <span class="hlt">topography</span> step height (60 nm) and the thicknesses of the organic films (20 nm - 100 nm) were typical for state-of-the-art IC manufacturing lithography processes. A lithographic proximity effect driven by wafer <span class="hlt">topography</span> pitch was experimentally observed for a single layer BARC system. The response was reproduced with good quantitative accuracy using rigorous wafer plane EMF simulations incorporating ideal etched wafer <span class="hlt">topography</span>, a planarizing resist film and a simple spin-coat approximation of the BARC coverage, as observed by x-section SEM. In contrast, simulations assuming the limiting cases of a perfectly conformal BARC and a perfectly planarizing BARC failed to predict any meaningful proximity effect.</p> <div class="credits"> <p class="dwt_author">Robertson, Stewart A.; Reilly, Michael T.; Graves, Trey; Biafore, John J.; Smith, Mark D.; Perret, Damien; Ivin, Vladimir; Potashov, Sergey; Silakov, Mikhail; Elistratov, Nikolay</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-03-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">377</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3623177"> <span id="translatedtitle">Effect of Micro- and Nanoscale <span class="hlt">Topography</span> on the Adhesion of Bacterial Cells to Solid Surfaces</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Attachment and biofilm formation by bacterial pathogens on surfaces in natural, industrial, and hospital settings lead to infections and illnesses and even death. Minimizing bacterial attachment to surfaces using controlled <span class="hlt">topography</span> could reduce the spreading of pathogens and, thus, the incidence of illnesses and subsequent human and financial losses. In this context, the attachment of key microorganisms, including Escherichia coli, Listeria innocua, and Pseudomonas fluorescens, to silica and alumina surfaces with micron and nanoscale <span class="hlt">topography</span> was investigated. The results suggest that orientation of the attached cells occurs preferentially such as to maximize their contact area with the surface. Moreover, the bacterial cells exhibited different morphologies, including different number and size of cellular appendages, depending on the topographical details of the surface to which they attached. This suggests that bacteria may utilize different mechanisms of attachment in response to surface <span class="hlt">topography</span>. These results are important for the design of novel microbe-repellant materials.</p> <div class="credits"> <p class="dwt_author">Hsu, Lillian C.; Fang, Jean; Borca-Tasciuc, Diana A.; Worobo, Randy W.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">378</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013MeScT..24j5010G"> <span id="translatedtitle">Calibration of the scales of areal surface <span class="hlt">topography</span> measuring instruments: part 3. Resolution</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Calibration of the scales of areal surface <span class="hlt">topography</span> measuring instruments requires testing of the resolution. Several designs of artefact that allow testing of the resolution of such instruments are currently available; however, analysis methods need to be developed to provide comparable results. A novel method for determining the lateral resolution of areal surface <span class="hlt">topography</span> measuring instruments is presented. The method uses a type ASP (star-shaped) material measure. To demonstrate the validity of the method, the resolution of a phase shifting interferometer was determined based on the ISO definition of the lateral period limit. Using the proposed method, the type ASP material measure, which is often used to judge qualitatively an instrument's resolution, can be used to quantitatively estimate the resolution of instruments using the <span class="hlt">topography</span> data.</p> <div class="credits"> <p class="dwt_author">Giusca, Claudiu L.; Leach, Richard K.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-10-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">379</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012IzAOP..48..973K"> <span id="translatedtitle">Reconstruction of mean dynamic <span class="hlt">topography</span> of the Black Sea for altimetry measurements</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In this study a new approach for reconstructing the Mean Dynamic <span class="hlt">Topography</span> of the Black Sea is applied. Constant observations (SVP measurements), drifters, and data of vertical sounding of the temperature and salt content together with measurements of sea level anomalies received from Topex/Poseidon mission satellite data were used. The absolute sea level received by altimetry data using the mean dynamic <span class="hlt">topography</span> received during work was compared to the dynamic level received according to independent marine surveys. The comparison showed that the method represented in the study permits one to define more exactly the dynamic <span class="hlt">topography</span> of the Black Sea when compared with the studies of previous authors. The results of this study will be useful to reconstruct the areas of the geostrophic currents according to satellite altimetry.</p> <div class="credits"> <p class="dwt_author">Kubryakov, A. A.; Stanichny, S. V.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">380</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/978296"> <span id="translatedtitle">Structural Characterization of Doped GaSb Single Crystals by X-ray <span class="hlt">Topography</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">We characterized GaSb single crystals containing different dopants (Al, Cd and Te), grown by the Czochralski method, by x-ray <span class="hlt">topography</span> and high angular resolution x-ray diffraction. Lang <span class="hlt">topography</span> revealed dislocations parallel and perpendicular to the crystal's surface. Double-crystal GaSb 333 x-ray <span class="hlt">topography</span> shows dislocations and vertical stripes than can be associated with circular growth bands. We compared our high-angular resolution x-ray diffraction measurements (rocking curves) with the findings predicted by the dynamical theory of x-ray diffraction. These measurements show that our GaSb single crystals have a relative variation in the lattice parameter ({Delta}d/d) on the order of 10{sup -5}. This means that they can be used as electronic devices (detectors, for example) and as x-ray monochromators.</p> <div class="credits"> <p class="dwt_author">Honnicke, M.G.; Mazzaro, I.; Manica, J.; Benine, E.; M da Costa, E.; Dedavid, B. A.; Cusatis, C.; Huang, X. R.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-09-13</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_18");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' 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onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">381</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2004RScI...75.2524W"> <span id="translatedtitle">Top-down <span class="hlt">topography</span> of deeply etched silicon in the scanning electron microscope</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">It is proposed to measure the cross sections of steep-sided etched lines and similar deep surface <span class="hlt">topography</span> on partially completed silicon integrated circuit wafers using either the backscattered electron (BSE) or the low-loss electron (LLE) image in the scanning electron microscope (SEM). These images contain regions where the collected signal is zero because there is no direct line of sight between the landing point of the electron beam on the specimen and the BSE or LLE detector. It is proposed to use the boundary of such a region in the SEM image as a geometrical line to measure the surface <span class="hlt">topography</span>. Or alternatively, a shadow can be seen in the distribution of either BSE or LLE with an image-forming detector system. The use of this shadow position on the detector to measure deep surface <span class="hlt">topography</span> will be demonstrated.</p> <div class="credits"> <p class="dwt_author">Wells, Oliver C.; Murray, Conal E.; Rullan, Jonathan L.; Gignac, Lynne M.</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-08-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">382</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/946355"> <span id="translatedtitle">A Generalized Subsurface Flow Parameterization Considering Subgrid Spatial Variability of Recharge and <span class="hlt">Topography</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Subsurface flow is an important hydrologic process and a key component of the water budget, especially in humid regions. In this study, a new subsurface flow formulation is developed that incorporates spatial variability of both <span class="hlt">topography</span> and recharge. It is shown through theoretical derivation and case studies that the power law and exponential subsurface flow parameterizations and the parameterization proposed by Woods et al.[1997] are all special cases of the new formulation. The subsurface flows calculated using the new formulation compare well with values derived from observations at the Tulpehocken Creek and Walnut Creek watersheds. Sensitivity studies show that when the spatial variability of <span class="hlt">topography</span> or recharge, or both is increased, the subsurface flows increase at the two aforementioned sites and the Maimai hillslope. This is likely due to enhancement of interactions between the groundwater table and the land surface that reduce the flow path. An important conclusion of this study is that the spatial variability of recharge alone, and/or in combination with the spatial variability of <span class="hlt">topography</span> can substantially alter the behaviors of subsurface flows. This suggests that in macroscale hydrologic models or land surface models, subgrid variations of recharge and <span class="hlt">topography</span> can make significant contributions to the grid mean subsurface flow and must be accounted for in regions with large surface heterogeneity. This is particularly true for regions with humid climate and relatively shallow groundwater table where the combined impacts of spatial variability of recharge and <span class="hlt">topography</span> are shown to be more important. For regions with arid climate and relatively deep groundwater table, simpler formulations, especially the power law, for subsurface flow can work well, and the impacts of subgrid variations of recharge and <span class="hlt">topography</span> may be ignored.</p> <div class="credits"> <p class="dwt_author">Huang, Maoyi; Liang, Xu; Leung, Lai R.</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-12-05</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">383</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2010ESSDD...3..231T"> <span id="translatedtitle">A consistent dataset of Antarctic ice sheet <span class="hlt">topography</span>, cavity geometry, and global bathymetry</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Sub-ice shelf circulation and freezing/melting rates in ocean general circulation models depend critically on an accurate and consistent representation of cavity geometry. Existing global or pan-Antarctic data sets have turned out to contain various inconsistencies and inaccuracies. The goal of this work is to compile independent regional fields into a global data set. We use the S-2004 global 1-min bathymetry as the backbone and add an improved version of the BEDMAP <span class="hlt">topography</span> (ALBMAP bedrock <span class="hlt">topography</span>) for an area that roughly coincides with the Antarctic continental shelf. The position of the merging line is individually chosen in different sectors in order to get the best out of each data set. High-resolution gridded data for ice shelf <span class="hlt">topography</span> and cavity geometry of the Amery, Fimbul, Filchner-Ronne, Larsen C and George VI Ice Shelves, and for Pine Island Glacier are carefully merged into the ambient ice and ocean <span class="hlt">topographies</span>. Multibeam survey data for bathymetry in the former Larsen B cavity and the southeastern Bellingshausen Sea have been obtained from the data centers of Alfred Wegener Institute (AWI), British Antarctic Survey (BAS) and Lamont-Doherty Earth Observatory (LDEO), gridded, and blended into the existing bathymetry map. The resulting global 1-min <span class="hlt">topography</span> data set (RTopo-1) contains maps for upper and lower ice surface heights, bedrock <span class="hlt">topography</span>, and consistent masks for open ocean, grounded ice, floating ice, and bare land surface. The data set is available in NetCDF format from the PANGAEA database at doi:10.1594/pangaea.741917.</p> <div class="credits"> <p class="dwt_author">Timmermann, R.; Le Brocq, A.; Deen, T.; Domack, E.; Dutrieux, P.; Galton-Fenzi, B.; Hellmer, H.; Humbert, A.; Jansen, D.; Jenkins, A.; Lambrecht, A.; Makinson, K.; Niederjasper, F.; Nitsche, F.; Nøst, O. A.; Smedsrud, L. H.; Smith, W. H. F.</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-07-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">384</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012JGRB..117.4402L"> <span id="translatedtitle">Constraints on 3-D stress in the crust from support of mid-ocean ridge <span class="hlt">topography</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The direction of crustal stresses acting at mid-ocean ridges is well characterized, but the magnitude of these stresses is poorly constrained. We present a method by which the absolute magnitude of these stresses may be constrained using seafloor <span class="hlt">topography</span> and gravity. The <span class="hlt">topography</span> is divided into a short-wavelength portion, created by rifting, magmatism, and transform faulting, and a long-wavelength portion associated with the cooling and subsidence of the oceanic lithosphere. The short-wavelength surface and Moho <span class="hlt">topography</span> are used to calculate the spatially varying 3-D stress tensor in the crust by assuming that in creating this <span class="hlt">topography</span>, the deviatoric stress reached the elastic-plastic limiting stress; the Moho <span class="hlt">topography</span> is constrained by short-wavelength gravity variations. Under these assumptions, an incompressible elastic material gives the smallest plastic failure stress associated with this <span class="hlt">topography</span>. This short-wavelength topographic stress generally predicts the wrong style of earthquake focal mechanisms at ridges and transform faults. However, the addition of an in-plane regional stress field is able to reconcile the combined crustal stress with both the ridge and transform focal mechanisms. By adjusting the magnitude of the regional stress, we determine a lower bound for in situ ridge-perpendicular extension of 25-40 MPa along the slow spreading mid-Atlantic ridge, 40-50 MPa along the ultra-slow spreading ridges in the western Indian Ocean, and 10-30 MPa along the fast spreading ridges of the southeastern Indian and Pacific Oceans. Furthermore, we constrain the magnitude of ridge-parallel extension to be between 4 and 8 MPa in the Atlantic Ocean, between -1 and 7 MPa in the western Indian Ocean, and between -1 and 3 MPa in the southeastern Indian and Pacific Oceans. These observations suggest that a deep transform valley is an essential feature of the ridge-transform spreading center.</p> <div class="credits"> <p class="dwt_author">Luttrell, Karen; Sandwell, David</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-04-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">385</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/23635202"> <span id="translatedtitle">Electrokinetic microscopy: a technique for imaging three-dimensional surface <span class="hlt">topography</span> and heterogeneity of surface material.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">In the present study, we introduce the concept of an electrokinetic microscope (EKM), a non-contact type probe microscope that can simultaneously provide a test specimen's three-dimensional surface <span class="hlt">topography</span> and heterogeneity of surface material. In the EKM, the flow impedance and the streaming potential are measured during the scanning process to reproduce the <span class="hlt">topography</span> and the heterogeneity, respectively. The working principle of the EKM is experimentally demonstrated by measuring specimens whose surfaces consist of thin layers of various materials and topographical differences. Experimental results also show that the EKM can be used regardless of the electrical conductivity of test specimens. PMID:23635202</p> <div class="credits"> <p class="dwt_author">Kwon, G H; Kim, T Y; Kim, S J</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-04-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">386</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013SPIE.8574E..0PD"> <span id="translatedtitle">Time-domain schemes of optical <span class="hlt">topography</span>: methodology, simulative and experimental validation</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">To cope with the low quantification in the established optical <span class="hlt">topography</span> that originates from the excessively simplified computation model based on the modified Lambert-Beer's Law (MLBL), we propose a least-squares fitting scheme for time-domain optical <span class="hlt">topography</span> that seeks for data matching between the time-resolved measurement and the model prediction calculated by analytically solving the time-domain diffusion equation in semi-infinite geometry. Our simulative and phantom experiments demonstrate that the proposed curve-fitting method is overall superior to the conventional MLBL-based one in quantitative performance.</p> <div class="credits"> <p class="dwt_author">Duan, Linjing; Wang, Xin; Li, Jiao; Yi, Xi; Wu, Linhui; Zhang, Limin; Gao, Feng</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-03-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">387</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2008AGUFM.U21A0011G"> <span id="translatedtitle"><span class="hlt">Topography</span> of Mercury from Stereophotoclinometric Analysis of MESSENGER Flyby 2 and Mariner 10 Images</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Imaging data acquired during the MESSENGER flybys of Mercury are being used to construct preliminary models of the surface <span class="hlt">topography</span> of the planet. These models will be improved when additional data become available from the orbital phase of the mission. For all three flybys the inbound and outbound views present a crescent and gibbous Mercury, respectively, each bounded by the terminator on one side and the limb on the other. Longitudes in the lit hemisphere between the two limbs will not be visible, and even less will be useful for topographic analysis due to the obliquity of the view. The first MESSENGER flyby on 14 January 2008 provided useful data for about 25 degrees in longitude from inbound imaging and about 80 degrees outbound; the latter became increasingly degraded as the sub-solar longitude was approached. Ideally, high-resolution <span class="hlt">topography</span> is determined from stereophotoclinometry (SPC), by which images at different illuminations are used to solve for <span class="hlt">topography</span> and albedo in small "maplets," the centers of which are control points for stereographic analysis and low-resolution <span class="hlt">topography</span>. During a single flyby, the illumination does not change, and close to the sub-solar point it is difficult to distinguish brightness variations due to <span class="hlt">topography</span> from those due to albedo variations. The second MESSENGER flyby of Mercury on 6 October 2008 will image longitudes from about 90 degrees W to 90 degrees E. From our experience with data from the first flyby, we will be able to solve for <span class="hlt">topography</span> from the images in a latitude range from 90 to 10 degrees W (outbound images) and, at lower resolution, from 75 to 90 degrees E (inbound images). Overlap between the MESSENGER and Mariner 10 data sets will allow for a true SPC analysis in much of the former region. Of particular interest will be the <span class="hlt">topography</span> of the many craters and scarps in this region as well as the hummocky region antipodal to the Caloris basin. During the first MESSENGER flyby, Mercury Laser Altimeter (MLA) observations were made along a path near the equator from 10 to 90 degrees E. <span class="hlt">Topography</span> from the inbound images will be compared with the MLA data where the two overlap.</p> <div class="credits"> <p class="dwt_author">Gaskell, R. W.; Gillis-Davis, J. J.; Sprague, A. L.</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">388</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2748554"> <span id="translatedtitle">Teaching <span class="hlt">topography</span>-based and selection-based verbal behavior to developmentally disabled individuals: Some considerations</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Augmentative and alternative communication systems are widely recommended for nonvocal developmentally disabled individuals, with selection-based systems becoming increasingly popular. However, theoretical and experimental evidence suggests that <span class="hlt">topography</span>-based communication systems are easier to learn. This paper discusses research relevant to the ease of acquisition of <span class="hlt">topography</span>-based and selection-based systems. Additionally, current practices for choosing and designing communication systems are reviewed in order to investigate the extent to which links have been made with available theoretical and experimental knowledge. A stimulus equivalence model is proposed as a clearer direction for practitioners to follow when planning a communication training program. Suggestions for future research are also offered.</p> <div class="credits"> <p class="dwt_author">Shafer, Esther</p> <p class="dwt_publisher"></p> <p class="publishDate">1993-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">389</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/23078758"> <span id="translatedtitle">Molecular response of Escherichia coli adhering onto nanoscale <span class="hlt">topography</span>.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Bacterial adhesion onto abiotic surfaces is an important issue in biology and medicine since understanding the bases of such interaction represents a crucial aspect in the design of safe implant devices with intrinsic antibacterial characteristics. In this framework, we investigated the effects of nanostructured metal substrates on Escherichia coli adhesion and adaptation in order to understand the bio-molecular dynamics ruling the interactions at the interface. In particular, we show how highly controlled nanostructured gold substrates impact the bacterial behavior in terms of morphological changes and lead to modifications in the expression profile of several genes, which are crucially involved in the stress response and fimbrial <span class="hlt">synthesis</span>. These results mainly demonstrate that E. coli cells are able to sense even slight changes in surface nanotopography and to actively respond by activating stress-related pathways. At the same time, our findings highlight the possibility of designing nanoengineered substrates able to trigger specific bio-molecular effects, thus opening the perspective of smartly tuning bacterial behavior by biomaterial design. PMID:23078758</p> <div class="credits"> <p class="dwt_author">Rizzello, Loris; Galeone, Antonio; Vecchio, Giuseppe; Brunetti, Virgilio; Sabella, Stefania; Pompa, Pier Paolo</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-10-18</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">390</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3552789"> <span id="translatedtitle">Molecular response of Escherichia coli adhering onto nanoscale <span class="hlt">topography</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Bacterial adhesion onto abiotic surfaces is an important issue in biology and medicine since understanding the bases of such interaction represents a crucial aspect in the design of safe implant devices with intrinsic antibacterial characteristics. In this framework, we investigated the effects of nanostructured metal substrates on Escherichia coli adhesion and adaptation in order to understand the bio-molecular dynamics ruling the interactions at the interface. In particular, we show how highly controlled nanostructured gold substrates impact the bacterial behavior in terms of morphological changes and lead to modifications in the expression profile of several genes, which are crucially involved in the stress response and fimbrial <span class="hlt">synthesis</span>. These results mainly demonstrate that E. coli cells are able to sense even slight changes in surface nanotopography and to actively respond by activating stress-related pathways. At the same time, our findings highlight the possibility of designing nanoengineered substrates able to trigger specific bio-molecular effects, thus opening the perspective of smartly tuning bacterial behavior by biomaterial design.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2012-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">391</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1996JGR...101.4691A"> <span id="translatedtitle">Analysis and interpretation of high-resolution <span class="hlt">topography</span> and gravity of Ishtar Terra, Venus</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The apparent depth of compensation (ADC) of the <span class="hlt">topography</span> of Venus, determined on a global scale using the Airy isostasy model, shows that the <span class="hlt">topography</span> specified by the spherical harmonics of degree lower than 10 is compensated at depths greater than 150 km, that of degree higher than about 35 is compensated at a constant depth of about 35 km, and the compensation depths of the harmonics of degree 10-35 shoal as the harmonic degree increases. Based on these characteristics of the globally determined ADC, three different maps of the <span class="hlt">topography</span> and gravitational potential of the Greater Ishtar Terra are derived using the harmonics of degree 1-75 (LW), 10-75 (IW), and 30-75 (SW), respectively. The LW maps of the <span class="hlt">topography</span> and potential do not correlate well, but the IW and SW maps show good correlation, emphasizing that the long-wavelength components of the gravitational potential over the Ishtar Terra have contributions from sources broader than the Terra. The energy of the gravitational potential of the <span class="hlt">topography</span> is about an order of magnitude greater than that of the observed potential, indicating that the <span class="hlt">topography</span> is strongly compensated. The ADC of the <span class="hlt">topography</span> is estimated by both spectral and space domain analysis. In the spectral domain, three independent procedures, the energy spectrum, the statistical method, and the wavelength-dependent method, are employed. The first two yield a mean ADC value for the entire spectrum, whereas the last one calculates the ADC for different wavelengths. The ADC decreases as the longer-wavelength components are excluded. The mean ADC values determined for the LW, IW, and SW maps by the energy spectrum method are 115, 65, and 40 km, respectively. Those calculated through the statistical method are 85, 55, and 34 km, respectively. These values reflect the upper and lower limits, because the energy spectrum method overestimates and the statistical method underestimates the ADC. The wavelength-dependent method shows that the ADCs of the wavelengths 500-1350 km are similar for all the maps but those of the longer wavelengths significantly differ among the maps. The mean ADC values also differ from the ADC of local topographic features. For example, the ADC of Maxwell Montes is about 55 km in both the LW and IW maps. In the space domain, the ADC is determined for Pratt and Airy isostasy models through fitting a linear and a quadratic function to the geoid height versus <span class="hlt">topography</span> data, respectively. The ADC values determined show good agreement with the above-mentioned values. In addition, the relationship between the high-resolution <span class="hlt">topography</span> and the line-of-sight acceleration residuals of the western Ishtar Terra specified by wavelengths of 300-500 km suggests that the high-resolution <span class="hlt">topography</span> is compensated at a depth of about 25 km. We also determine the lateral density perturbations inside a surface layer so that together with the <span class="hlt">topography</span> of the Greater Ishtar Terra they give rise to the observed gravitational potential over the Terra. Three layer thicknesses of 50, 100, and 200 km are examined. The resulting density perturbations are too large to be interpreted in terms of lateral temperature variations alone. This suggests lateral variations in the rock type; the crust beneath the mountain belts may contain considerable amounts of low-density material.</p> <div class="credits"> <p class="dwt_author">Arkani-Hamed, Jafar</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">392</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/27040317"> <span id="translatedtitle">Impact of Hillslope-Scale Organization of <span class="hlt">Topography</span>, Soil Moisture, Soil Temperature, and Vegetation on Modeling Surface Microwave Radiation Emission</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Microwave radiometry will emerge as an important tool for global remote sensing of near-surface soil moisture in the coming decade. In this modeling study, we find that hillslope-scale <span class="hlt">topography</span> (tens of meters) influences microwave brightness temperatures in a way that produces bias at coarser scales (kilometers). The physics underlying soil moisture remote sensing suggests that the effects of <span class="hlt">topography</span> on</p> <div class="credits"> <p class="dwt_author">Alejandro N. Flores; Valeriy Y. Ivanov; Dara Entekhabi; Rafael L. Bras</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">393</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/31516492"> <span id="translatedtitle">Variation in surface <span class="hlt">topography</span> of different NiTi orthodontic archwires in various commercial fluoride-containing environments</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">ObjectivesThe surface <span class="hlt">topography</span> can affect the friction behavior between an orthodontic wire and brackets during clinical applications. The purpose of this study was to investigate the influence of a fluoride-containing environment on the surface <span class="hlt">topography</span> variations of different nickel–titanium (NiTi) orthodontic archwires.</p> <div class="credits"> <p class="dwt_author">Her-Hsiung Huang</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">394</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/50189744"> <span id="translatedtitle"><span class="hlt">Topography</span>-driven variations in backscatter strength and depth observed over the Greenland Ice Sheet with InSAR</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">ERS radar observations of the Greenland Ice Sheet have yielded images characterized by small-scale (~10 km) variations in backscatter. While these variations are associated with <span class="hlt">topography</span>, they are not due to local incidence angle differences, since the undulations in <span class="hlt">topography</span> are small enough (~tens of meters in height) that changes in slope amount to less than a degree; moreover the</p> <div class="credits"> <p class="dwt_author">E. Weber Hoen; Howard A. Zebker</p> <p class="dwt_publisher"></p> <p class="publishDate">2000-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">395</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/56372169"> <span id="translatedtitle">The Surface Water and Ocean <span class="hlt">Topography</span> Mission: a mission concept to study the world's oceans and fresh water</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The Surface Water and Ocean <span class="hlt">Topography</span> (SWOT) is a planned satellite mission to study the world's oceans and terrestrial surface water bodies. The SWOT mission concept has been proposed jointly by the global Hydrology and Oceanography science communities to make the first global survey of the Earth's surface water, observe the fine details of the ocean's surface <span class="hlt">topography</span>, and measure</p> <div class="credits"> <p class="dwt_author">Parag Vaze; Vincent Albuys; Daniel Esteban-Fernandez; Thierry Lafon; Juliette Lambin; Alain Mallet; Ernesto Rodriguez</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">396</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/4983347"> <span id="translatedtitle">EFFECTS OF ARBITRARY SHAPED SURFACE <span class="hlt">TOPOGRAPHIES</span> ON EARTHQUAKE GROUND MOTION USING BOUNDARY ELEMENT METHOD IN TIME DOMAIN</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">In this paper, the direct boundary element method in time domain is used for the calculation of local amplifications of seismic waves by real 3-dimensional surface <span class="hlt">topographies</span>. The presented method is effective for modelling surface irregularities with arbitrary shapes under complex incident wave forms. A real <span class="hlt">topography</span> with particular importance in Iran, Urmia Hill, which represents a complex surface irregularity</p> <div class="credits"> <p class="dwt_author">M. RAHIMIAN; B. OMIDVAR; H. DERAKHSHAN; A. NOORZAD</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">397</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/40125268"> <span id="translatedtitle">Variability in soil chemistry and arbuscular mycorrhizal fungi in harvester ant nests: the influence of <span class="hlt">topography</span>, grazing and region</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Harvester ants are important disturbance agents across western North America, but the effects of ant disturbances on soils may vary considerably with <span class="hlt">topography</span> and land use. We examined how soil properties and arbuscular mycorrhizal (AM) fungi in harvester ant nests varied across spatial scales according to <span class="hlt">topography</span>, grazing regime and region. Soils from undisturbed areas were compared with nest disturbances</p> <div class="credits"> <p class="dwt_author">Season R. Snyder; Thomas O. Crist; Carl F. Friese</p> <p class="dwt_publisher"></p> <p class="publishDate">2002-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">398</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/54216738"> <span id="translatedtitle">Topographic Relaxation in a Spherical, Viscoelastic Planet: Implications for Long-Wavelength <span class="hlt">Topography</span> and Compensation of Lunar Basins</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary"><span class="hlt">Topography</span> and gravity anomalies on planets including the Earth and Moon have significant power at long wavelengths. The long wavelength anomalies can be supported statically by the elastic strength of the lithosphere or maintained dynamically through planetary mantle convection. The capacity of the elastic lithosphere to support <span class="hlt">topography</span> increases sharply with decreasing planetary radius due to membrane stresses, according to</p> <div class="credits"> <p class="dwt_author">M. T. Zuber; S. Zhong</p> <p class="dwt_publisher"></p> <p class="publishDate">1998-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">399</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/54285943"> <span id="translatedtitle">Determination of Sub-Ice <span class="hlt">Topography</span> in a Valley Glacier Environment Using Airborne Radar Sounding with Echo Discrimination Techniques</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The identification of subsurface radar echoes on Mars in areas where significant surface <span class="hlt">topography</span> exists will require careful echo source discrimination to avoid misinterpretation. We have developed these techniques for airborne radar sounding data in the Dry Valleys of Antarctica. This effort includes a radar data simulator that utilizes a lidar-generated digital elevation model (DEM) of nearby surface <span class="hlt">topography</span> to</p> <div class="credits"> <p class="dwt_author">J. W. Holt; D. D. Blankenship; D. L. Morse; M. E. Peters; S. D. Kempf; B. Johnson</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">400</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/60102346"> <span id="translatedtitle">Application of digital image analysis techniques to the Geyser's data and <span class="hlt">topography</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">This paper describes the results of digital image analysis and techniques applied to acoustic sounder data and topographic relief in the Geyser's region. The two dimensional fast Fourier transform (2DFFT) represents the spacial variability of a photographic image. The spacial variability of <span class="hlt">topography</span> in complex terrain can be represented in this way and insight into degree of complexity and dominating</p> <div class="credits"> <p class="dwt_author">Porch</p> <p class="dwt_publisher"></p> <p class="publishDate">1980-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_19");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> 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showDiv("page_22");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">401</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/14842899"> <span id="translatedtitle"><span class="hlt">Topography</span> of the core-mantle boundary and lateral homogeneity of the liquid core</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Separate inversions of travel-time residuals of waves reflected from and transmitted through the core-mantle boundary yield similar results in terms of spherical harmonic expansion of its <span class="hlt">topography</span> up to degree and order four. This indicates the absence of detectable lateral heterogeneity in the liquid core. The relief of the boundary is + or - 6 km but its flattening, determined</p> <div class="credits"> <p class="dwt_author">Andrea Morelli; Adam M. Dziewonski</p> <p class="dwt_publisher"></p> <p class="publishDate">1987-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">402</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://eric.ed.gov/?q=topography&id=EJ821874"> <span id="translatedtitle">Evaluation of a Pre-Treatment Assessment to Select Mand <span class="hlt">Topographies</span> for Functional Communication Training</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p class="result-summary">Recent research has suggested that variables related to specific mand <span class="hlt">topographies</span> targeted during functional communication training (FCT) can affect treatment outcomes. These include effort, novelty of mands, previous relationships with problem behavior, and preference. However, there is little extant research on procedures for identifying which…</p> <div class="credits"> <p class="dwt_author">Ringdahl, Joel E.; Falcomata, Terry S.; Christensen, Tory J.; Bass-Ringdahl, Sandie M.; Lentz, Alison; Dutt, Anuradha; Schuh-Claus, Jessica</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">403</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://cornea.berkeley.edu/pubs/84.pdf"> <span id="translatedtitle">The <span class="hlt">topography</span> of visual evoked response properties across the visual field</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Summary Visual evoked potentials (VEPs) to luminance and pattern reversal stimulation were derived for a large number of small areas throughout the central visual field. In one study, the field was tested with a stimulus array consisting of 64 equal-area patches. Local response components were extracted by independent m-sequence modulation of the patches. Field <span class="hlt">topographies</span> were compared between and within</p> <div class="credits"> <p class="dwt_author">H. A. Baseler; E. E. Sutter; S. A. Klein; T. Carney</p> <p class="dwt_publisher"></p> <p class="publishDate">1994-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">404</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/18645989"> <span id="translatedtitle">An explicit method for the nonlinear interaction between water waves and variable and moving bottom <span class="hlt">topography</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">A fully nonlinear and fully dispersive method for the interaction between free surface waves and a variable bottom <span class="hlt">topography</span> in space and time in three dimensions is derived. A Green function potential formulation expresses the normal velocity of the free surface in terms of the bathymetry and its motion. An explicit, fast version of the method is derived in Fourier</p> <div class="credits"> <p class="dwt_author">Dorian Fructus; John Grue</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">405</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/22678711"> <span id="translatedtitle">Effect of titanium surface <span class="hlt">topographies</span> on human bone marrow stem cells differentiation in vitro.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Coating characteristics of dental implants such as composition and <span class="hlt">topography</span> regulate cell response during implant healing. The aim of this study was to assess how surface <span class="hlt">topography</span> can affect osteogenic differentiation of mesenchymal stem cells (MSCs) by analyzing the expression levels of bone-related genes and MSCs marker. Thirty disk-shaped, commercially pure Grade 2 titanium samples (10 × 2 mm) with 3 different surface <span class="hlt">topographies</span> (DENTSPLY-Friadent GmbH, Mannheim, Germany) were used in the present study: 10 Ti machined disks (control), 10 Ti sandblasted and acid-etched disks (DPS(®)) and 10 sandblasted and acid-etched disks at high temperature (Plus(®)). Samples were processed for real-time reverse transcription-polymerase chain reaction (RT-PCR) analysis. By comparing machined and Plus(®) disks, quantitative real-time RT-PCR showed a significant reduction of the bone-related genes osteocalcin (BGLAP) and osteoblast transcriptional factor (RUNX2). The comparison between DPS(®) and Plus(®) disks showed a slight induction of all the genes examined (RUNX2, ALPL, COL1A1, COL3A1, ENG, FOSL1, SPP1, and SP7); only the expression of BGLAP remained stable. The present study, demonstrated that implant surface <span class="hlt">topography</span> affects osteoblast gene expression. Indeed, Plus(®) surface produces an effect on MSCs in the late differentiation stages. PMID:22678711</p> <div class="credits"> <p class="dwt_author">Perrotti, Vittoria; Palmieri, Annalisa; Pellati, Agnese; Degidi, Marco; Ricci, Laura; Piattelli, Adriano; Carinci, Francesco</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-06-08</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">406</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://svs.gsfc.nasa.gov/vis/a000000/a000700/a000773/index.html"> <span id="translatedtitle">Push in South of the Hellas Basin Showing <span class="hlt">Topography</span> from MOLA</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">Zoom into the region of Mars just south of the Hellas Basin showing <span class="hlt">topography</span> data from MOLA. Blue tones represent elevations of less than 2 kilometers, while reddish tones are greater than about 2.8 kilometers, relative to the mean equatorial height of Mars.</p> <div class="credits"> <p class="dwt_author">Biddlecome, Tom; Smith, David</p> <p class="dwt_publisher"></p> <p class="publishDate">1999-11-22</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">407</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/22877707"> <span id="translatedtitle">Atomic force microscopy investigation of the surface <span class="hlt">topography</span> and adhesion of nickel nanoparticles to submicrospherical silica</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Surface <span class="hlt">topography</span> and the adhesion of amorphous and polycrystalline nickel nanoparticles on the surface of silica submicrospheres (200–250 nm) were probed by atomic force microscopy (AFM). Probe areas down to 50×50 nm in dimension were scanned on a single submicrosphere immobilized in a thermoplastic resin bed. The rough surface of the silica submicrospheres at higher resolution may arise from secondary</p> <div class="credits"> <p class="dwt_author">S. Ramesh; Y Cohen; D Aurbach; A Gedanken</p> <p class="dwt_publisher"></p> <p class="publishDate">1998-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">408</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/23862182"> <span id="translatedtitle">Understanding the <span class="hlt">topography</span> effects on competitive adsorption on a nanosized anatase crystal: a molecular dynamics study.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Using Molecular Mechanics and Molecular Dynamics methods, we investigated at the atomistic level the <span class="hlt">topography</span> effects both on physisorption on different crystalline planes of TiO2 anatase and on the competitive adsorption when three different crystallographic faces were simultaneously present in an idealized nanosized crystal interacting with a simple heteroaromatic molecule experimentally used in sunlight-induced photosynthetic reaction. PMID:23862182</p> <div class="credits"> <p class="dwt_author">Raffaini, Giuseppina; Melone, Lucio; Punta, Carlo</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-07-16</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">409</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/762016"> <span id="translatedtitle">Basement Surface Faulting and <span class="hlt">Topography</span> for Savannah River Site and Vicinity</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">This report integrates the data from more than 60 basement borings and over 100 miles of seismic reflection profiling acquired on the Savannah River Site to map the <span class="hlt">topography</span> of the basement (unweathered rock) surface and faulting recorded on this surface.</p> <div class="credits"> <p class="dwt_author">Cumbest, R.J.</p> <p class="dwt_publisher"></p> <p class="publishDate">1998-12-17</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">410</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.tau.ac.il/~pinhas/papers/1997/Krichak_et_al_MAP_generator_1997a.pdf"> <span id="translatedtitle">Interaction of <span class="hlt">topography</span> and tropospheric flow — A possible generator for the Red Sea Trough?</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Summary Numerical investigation of the nature of one of the most typical Eastern Mediterranean atmospheric circulation phenomena — the Red Sea Trough is undertaken. The role of interaction of typical atmospheric flow systems with the local <span class="hlt">topography</span> of the North African region is analyzed with the help of idealized numerical simulations employing the Penn State and the National Center for</p> <div class="credits"> <p class="dwt_author">S. O. Krichak; P. Alpert; T. N. Krishnamurti</p> <p class="dwt_publisher"></p> <p class="publishDate">1997-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">411</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://eric.ed.gov/?q=groundwater&id=EJ960319"> <span id="translatedtitle">Going Underground: A Field Investigation and Lab Activity on Karst <span class="hlt">Topography</span> and Water Systems</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p class="result-summary">Students learn science best with activities that mirror the way scientists work. This article describes how geologists investigate groundwater flow systems in areas of karst <span class="hlt">topography</span>--geologic formations shaped by dissolving bedrock--and provides a way for students to replicate this research. Students also use electric current to model water…</p> <div class="credits"> <p class="dwt_author">O'Dell, Gary; Gonzalez-Espada, Wilson</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">412</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/52396064"> <span id="translatedtitle"><span class="hlt">Topography</span> of Venus and earth - A test for the presence of plate tectonics</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Comparisons of earth and Venus <span class="hlt">topography</span> by use of Pioneer\\/Venus radar altimetry are examined. Approximately 93% of the Venus surface has been mapped with a horizontal resolution of 200 km and a vertical resolution of 200 m. Tectonic troughs have been indicated in plains regions which cover 65% of Venus, and hypsometric comparisons between the two planets' elevation distributions revealed</p> <div class="credits"> <p class="dwt_author">J. W. Head; S. E. Yuter; S. C. Solomon</p> <p class="dwt_publisher"></p> <p class="publishDate">1981-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">413</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/21724105"> <span id="translatedtitle">Influence of <span class="hlt">topography</span> of an endovascular stent material on smooth muscle cell response.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">The phenotypic shift of smooth muscle cells (SMCs) from contractile to synthetic phenotype after endovascular stenting has been deemed to be the predominant cause of restenosis. Although substrate <span class="hlt">topography</span> has been shown to affect SMC response for a variety of polymers, effect of <span class="hlt">topography</span> on phenotype of SMCs has not been well studied for endovascular stent materials. Thus, the objective of the present study was to evaluate SMC phenotype, manifested in morphology, proliferation, and contractile marker smooth muscle ?-actin expression, as a function of 316L stainless steel <span class="hlt">topography</span>. Results of this study showed that the cells grown on micro-grooved surface (groove depth: 13 ?m) were significantly more elongated than those on the electropolished surface. Ascertained by repeated proliferation studies, cells grown on micro-grooved surface demonstrated a significantly lower proliferation rate relative to the electropolished surface. An enhanced expression of smooth muscle ?-actin grown on micro-grooved surface was also found near confluence. Furthermore, cells on electropolished surface demonstrated a substantial loss of smooth muscle ?-actin between days 1 and 4. Therefore, given the favorable SMC response reported in this study, our findings suggest that a micro-grooved <span class="hlt">topography</span> might prove beneficial for endovascular stent applications. PMID:21724105</p> <div class="credits"> <p class="dwt_author">Taneja, Vipul; Vertegel, Alexey; Langan, Eugene M; Laberge, Martine</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-07-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">414</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://geo.mff.cuni.cz/~pauer/papers/2006%20pauer%20et%20al.pdf"> <span id="translatedtitle">Modeling the dynamic component of the geoid and <span class="hlt">topography</span> of Venus</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">We analyze the Venusian geoid and <span class="hlt">topography</span> to determine the relative importance of isostatic, elastic and dynamic compensation mechanisms over different degree ranges. The geoid power spectrum plotted on a log-log scale shows a significant change in its slope at about degree 40, suggesting a transition from a predominantly dynamic compensation mechanism at lower degrees to an isostatic and\\/or elastic</p> <div class="credits"> <p class="dwt_author">M. Pauer; K. Fleming; O. Cadek</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-01-01</p> </div> </div> </div> </div> <div clas