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Sample records for absolute dynamic topography

  1. Evaluation of Absolute Dynamic Ocean Topography Profiles along the Brazilian Coast

    NASA Astrophysics Data System (ADS)

    Luz, R. T.; Bosch, W.; Freitas, S. R. C.; Heck, B.

    2009-04-01

    Based on a new approach, which consistently filters GRACE-based geoid undulations and altimetry-derived sea surface heights along the tracks of altimeter satellites, absolute dynamic ocean topography (DOT) profiles are estimated along the Brazilian coast. Such DOT profiles can be used to perform levelling over the sea. Connecting these profiles with Brazilian Geodetic Tide Gauge Network (RMPG) stations it would be possible to validate the current studies on the modernization of the Brazilian height system, extended over many thousand kilometers on land. The link with coastal reference sites would also allow to connect isolated height systems, e.g. north of the Amazonas River mouth. We perform long-term mean DOT-profiles of cross-calibrated altimeter satellites which operated for many years over repeated ground tracks (TOPEX, Jason-1, ERS-2). Moreover, we analyze the consistency among crossing profiles (single- and dual-satellite) in particular in areas with strong mesoscale currents. The extrapolation of DOT profiles towards selected RMPG stations is investigated. For this connection strategies are considered to overcome the degradation of coastal altimetry due to errors in ocean tide models and the land contamination of the radiometer observations.

  2. Dynamic Topography Revisited

    NASA Astrophysics Data System (ADS)

    Moresi, Louis

    2015-04-01

    Dynamic Topography Revisited Dynamic topography is usually considered to be one of the trinity of contributing causes to the Earth's non-hydrostatic topography along with the long-term elastic strength of the lithosphere and isostatic responses to density anomalies within the lithosphere. Dynamic topography, thought of this way, is what is left over when other sources of support have been eliminated. An alternate and explicit definition of dynamic topography is that deflection of the surface which is attributable to creeping viscous flow. The problem with the first definition of dynamic topography is 1) that the lithosphere is almost certainly a visco-elastic / brittle layer with no absolute boundary between flowing and static regions, and 2) the lithosphere is, a thermal / compositional boundary layer in which some buoyancy is attributable to immutable, intrinsic density variations and some is due to thermal anomalies which are coupled to the flow. In each case, it is difficult to draw a sharp line between each contribution to the overall topography. The second definition of dynamic topography does seem cleaner / more precise but it suffers from the problem that it is not measurable in practice. On the other hand, this approach has resulted in a rich literature concerning the analysis of large scale geoid and topography and the relation to buoyancy and mechanical properties of the Earth [e.g. refs 1,2,3] In convection models with viscous, elastic, brittle rheology and compositional buoyancy, however, it is possible to examine how the surface topography (and geoid) are supported and how different ways of interpreting the "observable" fields introduce different biases. This is what we will do. References (a.k.a. homework) [1] Hager, B. H., R. W. Clayton, M. A. Richards, R. P. Comer, and A. M. Dziewonski (1985), Lower mantle heterogeneity, dynamic topography and the geoid, Nature, 313(6003), 541-545, doi:10.1038/313541a0. [2] Parsons, B., and S. Daly (1983), The

  3. Inferring Cetacean Population Densities from the Absolute Dynamic Topography of the Ocean in a Hierarchical Bayesian Framework

    PubMed Central

    Pardo, Mario A.; Gerrodette, Tim; Beier, Emilio; Gendron, Diane; Forney, Karin A.; Chivers, Susan J.; Barlow, Jay; Palacios, Daniel M.

    2015-01-01

    We inferred the population densities of blue whales (Balaenoptera musculus) and short-beaked common dolphins (Delphinus delphis) in the Northeast Pacific Ocean as functions of the water-column’s physical structure by implementing hierarchical models in a Bayesian framework. This approach allowed us to propagate the uncertainty of the field observations into the inference of species-habitat relationships and to generate spatially explicit population density predictions with reduced effects of sampling heterogeneity. Our hypothesis was that the large-scale spatial distributions of these two cetacean species respond primarily to ecological processes resulting from shoaling and outcropping of the pycnocline in regions of wind-forced upwelling and eddy-like circulation. Physically, these processes affect the thermodynamic balance of the water column, decreasing its volume and thus the height of the absolute dynamic topography (ADT). Biologically, they lead to elevated primary productivity and persistent aggregation of low-trophic-level prey. Unlike other remotely sensed variables, ADT provides information about the structure of the entire water column and it is also routinely measured at high spatial-temporal resolution by satellite altimeters with uniform global coverage. Our models provide spatially explicit population density predictions for both species, even in areas where the pycnocline shoals but does not outcrop (e.g. the Costa Rica Dome and the North Equatorial Countercurrent thermocline ridge). Interannual variations in distribution during El Niño anomalies suggest that the population density of both species decreases dramatically in the Equatorial Cold Tongue and the Costa Rica Dome, and that their distributions retract to particular areas that remain productive, such as the more oceanic waters in the central California Current System, the northern Gulf of California, the North Equatorial Countercurrent thermocline ridge, and the more southern portion of

  4. Inferring cetacean population densities from the absolute dynamic topography of the ocean in a hierarchical Bayesian framework.

    PubMed

    Pardo, Mario A; Gerrodette, Tim; Beier, Emilio; Gendron, Diane; Forney, Karin A; Chivers, Susan J; Barlow, Jay; Palacios, Daniel M

    2015-01-01

    We inferred the population densities of blue whales (Balaenoptera musculus) and short-beaked common dolphins (Delphinus delphis) in the Northeast Pacific Ocean as functions of the water-column's physical structure by implementing hierarchical models in a Bayesian framework. This approach allowed us to propagate the uncertainty of the field observations into the inference of species-habitat relationships and to generate spatially explicit population density predictions with reduced effects of sampling heterogeneity. Our hypothesis was that the large-scale spatial distributions of these two cetacean species respond primarily to ecological processes resulting from shoaling and outcropping of the pycnocline in regions of wind-forced upwelling and eddy-like circulation. Physically, these processes affect the thermodynamic balance of the water column, decreasing its volume and thus the height of the absolute dynamic topography (ADT). Biologically, they lead to elevated primary productivity and persistent aggregation of low-trophic-level prey. Unlike other remotely sensed variables, ADT provides information about the structure of the entire water column and it is also routinely measured at high spatial-temporal resolution by satellite altimeters with uniform global coverage. Our models provide spatially explicit population density predictions for both species, even in areas where the pycnocline shoals but does not outcrop (e.g. the Costa Rica Dome and the North Equatorial Countercurrent thermocline ridge). Interannual variations in distribution during El Niño anomalies suggest that the population density of both species decreases dramatically in the Equatorial Cold Tongue and the Costa Rica Dome, and that their distributions retract to particular areas that remain productive, such as the more oceanic waters in the central California Current System, the northern Gulf of California, the North Equatorial Countercurrent thermocline ridge, and the more southern portion of the

  5. Mesoscale variability of the absolute dynamic topography in the Drake Passage and Scotia Sea in 1993-2014

    NASA Astrophysics Data System (ADS)

    Koshlyakov, Mikhail; Repina, Irina; Tarakanov, Roman

    2016-04-01

    Daily numerical maps of the absolute dynamics topography (ADT), which are published by the French CLS agency (www.aviso.oceanobs.com) were used for the investigation of synoptic (mesoscale) ocean eddies in the Drake Passage and Scotia Sea in 1993-2014. Parts of these maps with the closed ADT isopleths (isohypses) were detected by a precise numerical algorithm and were interpreted as places of the location of cyclonic and anticyclonic mesoscale eddies. In addition, curves of ζ²(t), where t is time and ζ (t) is disturbance of ADT relative to the mean value in 1993-2014 at a given point, were plotted at a number of points within the studied ocean region. These curves show two well pronounced time scales ("periods") of ζ²(t) fluctuations: a lesser scale of 100-500 days and a greater scale varying generally from 2 to 4.5 years manifesting as changes in the time intervals with low and high amplitudes of the lesser time scale ζ²(t) fluctuations. Comparison of the ζ²(t) curves with the ADT maps shows that these lesser scale fluctuations are related to the behavior of individual eddies: their propagation through a given point in the ocean, eddy generation or absorption of an eddy by an ACC jet. The theory of the geostrophic ocean turbulence allows us to suppose that the above mentioned greater time scale of ζ²(t) fluctuations is related to the energy exchange between the ACC jets and mesoscale eddies that appears in a given ocean region, as an alternation of the periods of intense generation of eddies by ACC jets and periods of increased reverse energy transfer from the eddies to jets. The fact revealed in this work that cyclonic (anticyclonic) eddies are adjacent from the north (south) to the ACC jets agrees with this supposition and opens the possibilities to analyze the dynamic influence of the eddy interaction with the individual ACC jets separately.

  6. Isostasy, flexure, and dynamic topography

    NASA Astrophysics Data System (ADS)

    Gvirtzman, Zohar; Faccenna, Claudio; Becker, Thorsten W.

    2016-06-01

    A fundamental scientific question is, what controls the Earth's topography? Although the theoretical principles of isostasy, flexure, and dynamic topography are widely discussed, the parameters needed to apply these principles are frequently not available. Isostatic factors controlling lithospheric buoyancy are frequently uncertain and non-isostatic factors, such as lithospheric bending towards subduction zones and dynamic topography, are hard to distinguish. The question discussed here is whether a set of simple rules that relate topography to lithospheric structure in various tectonic environments can be deduced in a way that missing parameters can be approximated; or does each area behave differently, making generalizations problematic. We contribute to this issue analyzing the Asia-Africa-Arabia-Europe domain following a top-down strategy. We compile a new crustal thickness map and remove the contribution of the crust from the observed elevation. Then, the challenge is to interpret the residual topography in terms of mantle lithosphere buoyancy and dynamics. Based on systematic relationships between tectonic environments and factors controlling topography, we argue that crustal buoyancy and mantle lithospheric density can be approximated from available geological data and that regions near mantle upwelling or downwelling are easily identified by their extreme residual topography. Yet, even for other areas, calculating lithospheric thickness from residual topography is problematic, because distinguishing variations in mantle lithosphere thickness from sub-lithospheric dynamics is difficult. Fortunately, the area studied here provides an opportunity to examine this issue. Based on the conjunction between the Afar Plume and the mid-ocean ridge in the nearby Gulf of Aden and southern Red Sea, we constrain the maximal amplitude of dynamic topography to ~ 1 km. This estimate is based on a narrow definition of dynamic topography that only includes sub

  7. Landscape response to changes in dynamic topography

    NASA Astrophysics Data System (ADS)

    Ruetenik, Gregory A.; Moucha, Robert; Hoke, Gregory D.

    2015-04-01

    Dynamic topography is characterized by broad wavelength, low amplitude undulations of the Earth's surface maintained by stresses arising from mantle convection. Earth's topography is thus an aggregate of both dynamic and isostatic topography that is modulated by surface processes and changes in topography and/or the climate can be recorded in the offshore sedimentary record. However, it is generally difficult to deconvolve this record into contributions from changes in climate, isostatic topography, and dynamic topography. Herein, we use a landscape evolution model that is capable of producing simulations at the necessary scale and resolution for quantifying landscape response to moderate changes in dynamic topography in the presence of flexural unloading and loading due to erosion and deposition. We demonstrate that moderate changes in dynamic topography coupled with flexural response imposed on a landscape with pre-existing relief and drainage divide, disequilibrates the landscape resulting in a measurable increase in erosion rates and corresponding sedimentary flux to the margin. The magnitude and timing of this erosional response to dynamic topography is dependent on several key landscape evolution parameters, most notably the erosion (advection) coefficient and effective elastic thickness. Moreover, to maximize this response, we find that changes in dynamic topography must be slow enough and long-lived for given rates of erosion otherwise the landscape will not have sufficient time to generate a response. Lastly, this anomalous flux can persist for a significant amount of time beyond the influence of dynamic topography change as the landscape strives to re-equilibrate.

  8. Flat Subduction and Dynamic Topography

    NASA Astrophysics Data System (ADS)

    Lithgow-Bertelloni, C. R.; Dávila, F. M.; Eakin, C. M.; Crameri, F.

    2014-12-01

    Mantle dynamics manifests at the surface via the horizontal motions of plates and the vertical deflections that influence topography and the non-hydrostatic geoid. The pioneering work of Mitrovica et al. (1989) and Gurnis (1990) on this dynamic topography revolutionized our understanding of sedimentary basin formation, sea level changes and continental flooding. The temporal evolution of subduction can explain the migration of basins and even the drainage reversal of the Amazon (Shephard et al., 2012; Eakin et al., 2014). Until recently, flat subduction has been seen as enhancing downward deflection of the overriding plate and increasing flooding. However, this interpretation depends crucially on the details of the morphology and density structure of the slab, which controls the loci and amplitude of the deflection. We tend to ignore morphological details in mantle dynamics because flow can smooth out short wavelength variations. We have shown instead that details matter! Using South America as a natural laboratory because of the large changes in morphology of the Nazca slab along strike, we show that downward deflection of the overriding plate and hence basin formation, do not occur over flat segments but at the leading edge, where slabs plunge back into the mantle. This is true in both Argentina and Peru. The temporal evolution from a 'normally' dipplng slab to a flat slab leads to uplift over flat segments rather than enhanced subsidence. Critical for this result is the use of a detailed morphological model of the present-day Nazca slab with a spatial resolution of 50-100 km and based on relocated seismicity and magnetotelluric results. The density structure of the slab, due to age and the presence of overthickened crust from aseismic ridge subduction is essential. Overthickened crust leads to buoyant slabs. We reproduce formation and deposition of the Acres-Solimoes basin and the evolution of the Amazon drainage basin in Peru as well as the Mar Chiquita

  9. Absolute 3D reconstruction of thin films topography in microfluidic channels by interference reflection microscopy.

    PubMed

    Huerre, A; Jullien, M-C; Theodoly, O; Valignat, M-P

    2016-03-01

    The travel of droplets, bubbles, vesicles, capsules, living cells or small organisms in microchannels is a hallmark in microfluidics applications. A full description of the dynamics of such objects requires a quantitative understanding of the complex hydrodynamic and interfacial interactions between objects and channel walls. In this paper, we present an interferometric method that allows absolute topographic reconstruction of the interspace between an object and channel walls for objects confined in microfluidic channels. Wide field microscopic imaging in reflection interference contrast mode (RICM) is directly performed at the bottom wall of microfluidic chips. Importantly, we show that the reflections at both the lower and upper surface of the microchannel have to be considered in the quantitative analysis of the optical signal. More precisely, the contribution of the reflection at the upper surface is weighted depending on the light coherence length and channel height. Using several wavelengths and illumination apertures, our method allows reconstructing the topography of thin films on channel walls in a range of 0-500 nm, with a precision as accurate as 2 nm for the thinnest films. A complete description of the protocol is exemplified for oil in water droplets travelling in channels of height 10-400 μm at a speed up to 5 mm s(-1). PMID:26830018

  10. Mean Dynamic Topography of the Arctic Ocean

    NASA Technical Reports Server (NTRS)

    Farrell, Sinead Louise; Mcadoo, David C.; Laxon, Seymour W.; Zwally, H. Jay; Yi, Donghui; Ridout, Andy; Giles, Katherine

    2012-01-01

    ICESat and Envisat altimetry data provide measurements of the instantaneous sea surface height (SSH) across the Arctic Ocean, using lead and open water elevation within the sea ice pack. First, these data were used to derive two independent mean sea surface (MSS) models by stacking and averaging along-track SSH profiles gathered between 2003 and 2009. The ICESat and Envisat MSS data were combined to construct the high-resolution ICEn MSS. Second, we estimate the 5.5-year mean dynamic topography (MDT) of the Arctic Ocean by differencing the ICEn MSS with the new GOCO02S geoid model, derived from GRACE and GOCE gravity. Using these satellite-only data we map the major features of Arctic Ocean dynamical height that are consistent with in situ observations, including the topographical highs and lows of the Beaufort and Greenland Gyres, respectively. Smaller-scale MDT structures remain largely unresolved due to uncertainties in the geoid at short wavelengths.

  11. Mean dynamic topography of the Arctic Ocean

    NASA Astrophysics Data System (ADS)

    Farrell, Sinéad Louise; McAdoo, David C.; Laxon, Seymour W.; Zwally, H. Jay; Yi, Donghui; Ridout, Andy; Giles, Katharine

    2012-01-01

    ICESat and Envisat altimetry data provide measurements of the instantaneous sea surface height (SSH) across the Arctic Ocean, using lead and open water elevation within the sea ice pack. First, these data were used to derive two independent mean sea surface (MSS) models by stacking and averaging along-track SSH profiles gathered between 2003 and 2009. The ICESat and Envisat MSS data were combined to construct the high-resolution ICEn MSS. Second, we estimate the 5.5-year mean dynamic topography (MDT) of the Arctic Ocean by differencing the ICEn MSS with the new GOCO02S geoid model, derived from GRACE and GOCE gravity. Using these satellite-only data we map the major features of Arctic Ocean dynamical height that are consistent with in situ observations, including the topographical highs and lows of the Beaufort and Greenland Gyres, respectively. Smaller-scale MDT structures remain largely unresolved due to uncertainties in the geoid at short wavelengths.

  12. Global dynamic topography: geoscience communities requirements

    NASA Astrophysics Data System (ADS)

    Dewez, T.; Costeraste, J.

    2012-04-01

    The advent of free-of-charge global topographic data sets SRTM and Aster GDEM have enabled testing a host of geoscience hypotheses. This is because they first revealed the relief of previously unavailable earth landscapes, enabled quantitative geomorphometric analyses across entire landscapes and improved the resolution of measurements. Availability of such data is now considered standard, and though resolved at 30-m to 90-m pixel, which is amazing seeing where we come from, they are now regarded as mostly obsolete given the sub-meter imagery coming through web services like Google Earth. Geoscientists now appear to desire two additional features: field-scale-compatible elevation datasets (i.e. meter-scale digital models and sub-meter elevation precision) and dispose of regularly updated topography to retrieve earth surface changes, while retaining the key for success: data availability at no charge. A new satellite instrument is currently under phase 0 study at CNES, the French space agency, to fulfil these aims. The scientific community backing this demand is that of natural hazards, glaciology and to a lesser extent the biomass community. The system under study combines a native stereo imager and a lidar profiler. This combination provides spatially resolved elevation swaths together with absolute along-track elevation control point profiles. Data generated through this system, designed for revisit time better than a year, is intended to produce not only single acquisition digital surface models, colour orthoimages and small footprint full-wave-form lidar profiles to update existing topographic coverages, but also time series of them. This enables 3D change detection with centimetre-scale planimetric precision and metric vertical precision, in complement of classical spectral change appoaches. The purpose of this contribution, on behalf of the science team, is to present the mission concepts and philosophy and the scientific needs for such instrument including

  13. Evolution of Neogene Dynamic Topography in Madagascar

    NASA Astrophysics Data System (ADS)

    Paul, J. D.; Roberts, G.; White, N. J.

    2012-12-01

    Madagascar is located on the fringes of the African superswell. Its position and the existence of a +30 mGal long wavelength free-air gravity anomaly suggest that its present-day topography is maintained by convective circulation of the sub-lithospheric mantle. Residual depth anomalies of oceanic crust encompassing the island imply that Madagascar straddles a dynamic topographic gradient. In June-July 2012, we examined geologic evidence for Neogene uplift around the Malagasy coastline. Uplifted coral reef deposits, fossil beach rock, and terraces demonstrate that the northern and southern coasts are probably being uplifted at a rate of ~0.2 mm/yr. Rates of uplift clearly vary around the coastline. Inland, extensive peneplains occur at elevations of 1 - 2 km. These peneplains are underlain by 10 - 20 m thick laterite deposits, and there is abundant evidence for rapid erosion (e.g. lavaka). Basaltic volcanism also occurred during Neogene times. These field observations can be combined with an analysis of drainage networks to determine the spatial and temporal pattern of convectively driven uplift. ~100 longitudinal river profiles were extracted from a digital elevation model of Madagascar. An inverse model is then used to minimize the misfit between observed and calculated river profiles as a function of uplift rate history. During inversion, the residual misfit decreases from ~20 to ~4. Our results suggest that youthful and rapid uplift of 1-2 km occurred at rates of 0.2-0.4 mm/yr during the last ˜15 Myr. The algorithm resolves distinct phases of uplift which generate localized swells of high topography and relief (e.g. the Hauts Plateaux). Our field observations and modeling indicate that the evolution of drainage networks may contain useful information about mantle convective processes.

  14. Lower mantle heterogeneity, dynamic topography and the geoid

    NASA Technical Reports Server (NTRS)

    Hager, B. H.; Clayton, R. W.; Richards, M. A.; Comer, R. P.; Dziewonski, A. M.

    1984-01-01

    Density contrasts in the lower mantle, recently imaged using seismic tomography, drive convective flow which results in kilometers of dynamically maintained topography at the core-mantle boundary and at the Earth's surface. The total gravity field due to interior density contrasts and boundary topography predicts the largest wavelength components of the geoid remarkably well. Neglecting dynamic surface deformation leads to geoid anomalies of opposite sign than are observed.

  15. Lower mantle heterogeneity, dynamic topography and the geoid

    NASA Technical Reports Server (NTRS)

    Hager, B. H.; Clayton, R. W.; Richards, M. A.; Comer, R. P.; Dziewonski, A. M.

    1985-01-01

    Density contrasts in the lower mantle, recently imaged using seismic tomography, drive convective flow which results in kilometers of dynamically maintained topography at the core-mantle boundary and at the earth's surface. The total gravity field due to interior density constrasts and boundary topography predicts the largest wavelength components of the geoid remarkably well. Neglecting dynamic surface deformation leads to geoid anomalies of opposite sign than are observed.

  16. Mercury's Thermal Evolution, Dynamical Topography and Geoid

    NASA Astrophysics Data System (ADS)

    Ziethe, Ruth; Benkhoff, Johannes

    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

  17. Evolution of Neogene Dynamic Topography in Africa

    NASA Astrophysics Data System (ADS)

    Paul, Jonathan; Roberts, Gareth; White, Nicky

    2013-04-01

    The characteristic basins and swells of Africa's surface topography probably reflect patterns of convective circulation in the sub-lithospheric mantle. We have interrogated drainage networks to determine the spatial and temporal pattern of convectively driven uplift. ~560 longitudinal river profiles were extracted from a digital elevation model of Africa. An inverse model is then used to minimise the misfit between observed and calculated river profiles as a function of uplift rate history. During inversion, the residual misfit decreases from ~22 to ~5. Our results suggest that Africa's topography began to grow most rapidly after ~30 Ma at peak uplift rates of 0.1-0.15 mm/yr. The algorithm resolves distinct phases of uplift which generate localized swells of high topography and relief (e.g. the Angolan Dome). Uplift rate histories are shown to vary significantly from swell to swell. The calculated magnitudes, timing, and location of uplift agree well with local independent geological constraints, such as intense volcanism at Hoggar (42-39 Ma) and Afar (31-29 Ma), uplifted marine terraces, and warped peneplains. We have also calculated solid sediment flux histories for major African deltas which have persisted through time. This onshore record provides an important indirect constraint on the history of vertical motions at the surface, and agrees well with the offshore flux record, obtained from mapping isopachs of deltaic sediments. Our modelling and reconstructed sedimentary flux histories indicate that the evolution of drainage networks may contain useful information about mantle convective processes.

  18. Mercury's Thermal Evolution, Dynamical Topography and Geoid

    NASA Astrophysics Data System (ADS)

    Ziethe, Ruth; Benkhoff, Johannes

    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

  19. Zooplankton patch dynamics: daily gap formation over abrupt topography

    NASA Astrophysics Data System (ADS)

    Genin, Amatzia; Greene, Charles; Haury, Loren; Wiebe, Peter; Gal, Gideon; Kaartvedt, Stein; Meir, Eli; Fey, Connie; Dawson, Jim

    1994-05-01

    Net tow and acoustic surveys of zooplankton distributions were made over and around Sixtymile Bank (110 km southwest of San Diego, California). Gaps devoid of vertically migrating zooplankton were formed every evening above the summit of the bank. Interactions between the migrating animals, their predators, physical advection and the local topography appear to determine the gap formation and dynamics. Gaps were transported downstream during the night and appeared to disintegrate slowly through vertical swimming behavior, current shear and mixing processes. Patch dynamics following gap formation, mediated by both ocean currents and animal behavior, should augment the spatial heterogeneity of zooplankton and affect marine food webs in areas where abrupt topography features are common.

  20. Present-day dynamic and residual topography in central Anatolia

    NASA Astrophysics Data System (ADS)

    Uluocak, Ebru Şengül; Pysklywec, Russell; Göğüş, Oğuz H.

    2016-06-01

    The Central Anatolian orogenic plateau is represented by young volcanism, rapid plateau uplift, and distinctive (past and active) tectonic deformation. In this study, we consider observational data in terms of regional present-day geodynamics in the region. The residual topography of Central Anatolia was derived to define the regional isostatic conditions according to Airy isostasy and infer the potential role of "dynamic topography". Two-dimensional thermo-mechanical forward models for coupled mantle-lithosphere flow/deformation were conducted along a N-S directional profile through the region (e.g. northern/Pontides, interior, and southern/Taurides). These models were based on seismic tomography data that provide estimates about the present-day mantle thermal structure beneath the Anatolian plate. We compare the modelling results with calculated residual topography and independent data sets of geological deformation, gravity, and high surface heat flow/widespread geothermal activity. Model results suggest that there is ˜1 km of mantle flow induced dynamic topography associated with the sub-lithospheric flow driven by the seismically-inferred mantle structure. The uprising mantle may have also driven the asthenospheric source of volcanism in the north (e.g. Galatia volcanic province) and the Cappadocia volcanic province in the south while elevating the surface in the last 10 Myrs. Our dynamic topography calculations emphasize the role of vertical forcing under other orogenic plateaux underlain by relatively thin crust and low-density asthenospheric mantle.

  1. Upper-Mantle Flow Driven Dynamic Topography in Eastern Anatolia

    NASA Astrophysics Data System (ADS)

    Sengul Uluocak, Ebru; Pysklywec, Russell; Eken, Tuna; Hakan Gogus, Oguz

    2016-04-01

    Eastern Anatolia is characterized by 2 km plateau uplift -in the last 10 Myrs-, high surface heat flow distribution, shallow Curie-point depth, anomalous gravity field. Seismological observations indicate relatively high Pn and Sn attenuation and significant low seismic velocity anomalies in the region. Moreover, the surface geology is associated predominantly with volcanic rocks in which melt production through mantle upwelling (following lithospheric delamination) has been suggested. It has been long known that the topographic loading in the region cannot be supported by crustal thickness (~45 km) based on the principle of Airy isostasy. Recent global geodynamic studies carried out for evaluating the post-collisional processes imply that there is an explicit dynamic uplift in Eastern Anatolia and its adjacent regions. In this study we investigate the instantaneous dynamic topography driven by 3-D upper-mantle flow in Eastern Anatolia. For this purpose we conducted numerous thermo-mechanical models using a 2-D Arbitrary Lagrangian Eulerian (ALE) finite element method. The available P-wave tomography data extracted along 10 profiles were used to obtain depth-dependent density anomalies in the region. We present resulting dynamic topography maps and estimated 3D mantle flow velocity vectors along these 2-D cross sections for each profile. The residual topography based on crustal thickness and observed topography was calculated and compared with other independent datasets concerning geological deformation and dynamic topography predictions. The results indicate an upper mantle driven dynamic uplift correlated with the under-compensated characteristic in Eastern Anatolia. We discuss our results combined with 3D mantle flow by considering seismic anisotropy studies in the region. Initial results indicate that high dynamic uplift and the localized low Pn velocities in concurrence with Pn anisotropy structures show nearly spatial coherence in Eastern Anatolia.

  2. Mantle Flow Pattern and Dynamic Topography beneath the Eastern US

    NASA Astrophysics Data System (ADS)

    Liu, S.; King, S. D.; Adam, C. M.; Long, M. D.; Benoit, M. H.; Kirby, E.

    2015-12-01

    The complex tectonic history of the eastern US over the past billion years includes episodes of subduction and rifting associated with two complete cycles of supercontinent assembly and breakup. Both the previous global tomography models (S40RTS, SAVANI, TX2011, GyPSuM, SMEAN) and the analysis of the shear-wave splitting from the broadband seismic stations find a distinct coast-to-inland differentiation pattern in the lithosphere and upper mantle. The Mid-Atlantic Geophysical Integrative Collaboration (MAGIC) includes a dense linear seismic array from the Atlantic coast of Virginia to the western boarder of Ohio, crossing several different tectonic zones. To derive the regional mantle flow pattern along with its surface expression such as dynamic topography and aid the interpretation of the seismic observations, we are building a new geodynamic model based on ASPECT (Advanced Solver for Problems in Earth CovecTion) that uses buoyancy derived from seismic tomography along with realistic lithosphere and sub-lithosphere structure. At present, we use S40RTS and SAVANI tomography models together with the temperature-dependent viscosity to compute the mantle flow and dynamic topography. Beneath the eastern US, the upper mantle flow in our model is primarily parallel to the trend of the Appalachian belt, which is broadly consistent with the direction of the local shear-wave splitting. The dynamic topography results exhibit a coast-to-inland magnitude differentiation along the MAGIC seismic deployment. The numerical tests also show that both the magnitude and pattern of the dynamic topography are quite sensitive to the density perturbation and rigidity of the lithosphere/sub-lithosphere. Our future work involves using other tomography and viscosity models to obtain the mantle flow pattern as well as the resulting dynamic topography and geoid.

  3. Impact of lithosphere rheology on the dynamic topography

    NASA Astrophysics Data System (ADS)

    Burov, Evgueni; Gerya, Taras; Koptev, Alexander

    2014-05-01

    Dynamic topography is a key observable signature of the Earth's and planetary (e.g. Venus) mantle dynamics. In general view, it reflects complex mantle flow patterns, and hence is supposed to correlate at different extent with seismic tomography, SKS fast orientations, geodetic velocity fields and geoid anomalies. However, identification of dynamic topography had no systematic success, specifically in the Earth's continents. Here we argue that lithosphere rheology, in particular, rheological stratification of continents, results in modulation of dynamic topography, converting commonly expected long-wavelength/small amplitude undulations into short-wavelength surface undulations with wide amplitude spectrum, superimposed onto "tectonic" topography. These ideas are explored in 3D using unprecedentedly high resolution numerical experiments (grid step size 2-3 km for 1500x1500x600 km computational area) incorporating realistic rheologically stratified lithosphere. Such high resolution is actually needed to resolve small-scale crustal faulting and inter-layer coupling/uncoupling that shape surface topography. The results reveal strikingly discordant, counterintuitive features of 3D dynamic topography, going far beyond the inferences from previous models. In particular, even weak anisotropic tectonic stress field results both in large-scale small-amplitude dynamic topography and in strongly anisotropic short-wavelength (at least in one direction) dynamic topography with wide amplitude range (from 100 to 2000-3000 m), including basins and ranges and large-scale linear normal and strike-slip faults. Even very slightly pre-stressed strong lithosphere yields and localizes deformation much easier , than un-prestressed one, in response to plume impact and mantle flow. The results shed new light on the importance of lithosphere rheology and active role of lithosphere in mantle-lithosphere interactions as well as on the role of mantle flow and far-field stresses in tectonic

  4. Predicting surface dynamic topographies of stagnant lid planetary bodies

    NASA Astrophysics Data System (ADS)

    Dumoulin, C.; Čadek, O.; Choblet, G.

    2013-12-01

    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

  5. Dynamic topography in subduction zones: insights from laboratory models

    NASA Astrophysics Data System (ADS)

    Bajolet, Flora; Faccenna, Claudio; Funiciello, Francesca

    2014-05-01

    The topography in subduction zones can exhibit very complex patterns due to the variety of forces operating this setting. If we can deduce the theoretical isostatic value from density structure of the lithosphere, the effect of flexural bending and the dynamic component of topography are difficult to quantify. In this work, we attempt to measure and analyze the topography of the overriding plate during subduction compared to a pure shortening setting. We use analog models where the lithospheres are modeled by thin-sheet layers of silicone putty lying on low-viscosity syrup (asthenosphere). The model is shorten by a piston pushing an oceanic plate while a continental plate including a weak zone to localize the deformation is fixed. In one type of experiments, the oceanic plate bends and subducts underneath the continental one; in a second type the two plates are in contact without any trench, and thus simply shorten. The topography evolution is monitored with a laser-scanner. In the shortening model, the elevation increases progressively, especially in the weak zone, and is consistent with expected isostatic values. In the subduction model, the topography is characterized, from the piston to the back-wall, by a low elevation of the dense oceanic plate, a flexural bulge, the trench forming a deep depression, the highly elevated weak zone, and the continental upper plate of intermediate elevation. The topography of the upper plate is consistent with isostatic values for very early stages, but exhibits lower elevations than expected for later stages. For a same amount of shortening of the continental plate, the thickening is the same and the plate should have the same elevation in both types of models. However, comparing the topography at 20, 29 and 39% of shortening, we found that the weak zone is 0.4 to 0.6 mm lower when there is an active subduction. Theses values correspond to 2.6 to 4 km in nature. Although theses values are high, there are of the same order as

  6. The effects of abrupt topography on plankton dynamics.

    PubMed

    Zavala Sansón, L; Provenzale, A

    2009-12-01

    Plankton population dynamics in the upper layer of the ocean depends on upwelling processes that bring nutrients from deeper waters. In turn, these depend on the structure of the vertical velocity field. In coastal areas and in oceanic regions characterized by the presence of strong submarine topographic features, the variable bottom topography induces significant effects on vertical velocities and upwelling/downwelling patterns. As a consequence, large plankton and fish abundances are frequently observed above seamounts, canyons and steep continental shelves. In this work, the dynamics of an NPZ (nutrient-phytoplankton-zooplankton) system is numerically studied by coupling the ecosystem model with a quasi two-dimensional (2D) fluid model with topography. At variance with classical 2D approaches, this formulation allows for an explicit expression of the vertical motions produced when fluid columns are squeezed and stretched as they experience changes of depth. Thus, input or output of nutrients at the surface are associated with fluid motion over the bottom topography. We examine the dynamics of a cyclonic vortex over two basic topographies: a steep escarpment and a submarine mountain. We show that plankton abundance over the escarpment is modulated by the passing of topographic Rossby waves, generated by the vortex-topography interaction. In such configuration, advection effects driven by the flow over the escarpment are of limited relevance for the dynamics of biological fields. By contrast, we find that the flow resulting from the interaction of a vortex with a seamount is sufficiently strong and persistent to allow for a remarkable increase of nutrients, and a corresponding enhancement of phytoplankton and zooplankton concentrations. Over the seamount, advection effects associated with trapped flow perturbations around the summit play an essential role. PMID:19737575

  7. On the ratio of dynamic topography and gravity anomalies in a dynamic Earth

    NASA Astrophysics Data System (ADS)

    Colli, L.; Ghelichkhan, S.; Bunge, H.-P.

    2016-03-01

    Growing evidence from a variety of geologic indicators points to significant topography maintained convectively by viscous stresses in the mantle. However, while gravity is sensitive to dynamically supported topography, there are only small free-air gravity anomalies (<30 mGal) associated with Earth's long-wavelength topography. This has been used to suggest that surface heights computed assuming a complete isostatic equilibrium provide a good approximation to observed topography. Here we show that the apparent paradox is resolved by the well-established formalism of global, self-gravitating, viscously stratified Earth models. The models predict a complex relation between dynamic topography, mass, and gravity anomalies that is not summarized by a constant admittance—i.e., ratio of gravity anomalies to surface deflections—as one would infer from analytic flow solutions formulated in a half-space. Our results suggest that sizable dynamic topography may exist without a corresponding gravity signal.

  8. Dynamic wetting and spreading and the role of topography.

    PubMed

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

    2009-11-18

    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 θ and θ(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

  9. Solitary wave dynamics in shallow water over periodic topography.

    PubMed

    Nakoulima, Ousseynou; Zahibo, Narcisse; Pelinovsky, Efim; Talipova, Tatiana; Kurkin, Andrey

    2005-09-01

    The problem of long-wave scattering by piecewise-constant periodic topography is studied both for a linear solitary-like wave pulse, and for a weakly nonlinear solitary wave [Korteweg-de Vries (KdV) soliton]. If the characteristic length of the topographic irregularities is larger than the pulse length, the solution of the scattering problem is obtained analytically for a leading wave in the framework of linear shallow-water theory. The wave decrement in the case of the small height of the topographic irregularities is proportional to delta2, where delta is the relative height of the topographic obstacles. An analytical approximate solution is also obtained for the weakly nonlinear problem when the length of the irregularities is larger than the characteristic nonlinear length scale. In this case, the Korteweg-de Vries equation is solved for each piece of constant depth by using the inverse scattering technique; the solutions are matched at each step by using linear shallow-water theory. The weakly nonlinear solitary wave decays more significantly than the linear solitary pulse. Solitary wave dynamics above a random seabed is also discussed, and the results obtained for random topography (including experimental data) are in reasonable agreement with the calculations for piecewise topography. PMID:16253002

  10. Dynamic topography and the Cenozoic carbonate compensation depth

    NASA Astrophysics Data System (ADS)

    Campbell, S. M.; Moucha, R.; Raymo, M. E.; Derry, L. A.

    2015-12-01

    The carbonate compensation depth (CCD), the ocean depth at which the calcium carbonate accumulation rate goes to zero, can provide valuable insight into climatic and weathering conditions over the Cenozoic. The paleoposition of the CCD can be inferred from sediment core data. As the carbonate accumulation rate decreases linearly with depth between the lysocline and CCD, the CCD can be calculated using a linear regression on multiple sediment cores with known carbonate accumulation rates and paleodepths. It is therefore vital to have well-constrained estimates of paleodepths. Paleodepths are typically calculated using models of thermal subsidence and sediment loading and compaction. However, viscous convection-related stresses in the mantle can warp the ocean floor by hundreds of meters over broad regions and can also vary significantly over millions of years. This contribution to paleobathymetry, termed dynamic topography, can be calculated by modeling mantle flow backwards in time. Herein, we demonstrate the effect dynamic topography has on the inference of the late Cenozoic CCD with an example from the equatorial Pacific, considering sites from IODP Expeditions 320/321. The equatorial Pacific, given its large size and high productivity, is closely tied to the global carbon cycle. Accordingly, long-term changes in the equatorial Pacific CCD can be considered to reflect global changes in weathering fluxes and the carbon cycle, in addition to more regional changes in productivity and thermohaline circulation. We find that, when the dynamic topography contribution to bathymetry is accounted for, the equatorial Pacific CCD is calculated to be appreciably shallower at 30 Ma than previous estimates would suggest, implying a greater deepening of the Pacific CCD over the late Cenozoic.

  11. Dynamic wetting and spreading and the role of topography

    NASA Astrophysics Data System (ADS)

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

    2009-11-01

    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, ve, to the dynamic and equilibrium contact angles θ and θe through v_{\\mathrm {e}} \\propto \\theta (\\theta^{2}-\\theta_{\\mathrm {e}}^{2}) . 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

  12. Isostatic and dynamic support of high topography on a North Atlantic passive margin

    NASA Astrophysics Data System (ADS)

    Pedersen, Vivi K.; Huismans, Ritske S.; Moucha, Robert

    2016-07-01

    Substantial controversy surrounds the origin of high topography along passive continental margins. Here we focus on the well-documented elevated passive margin in southwestern Scandinavia, and quantify the relative contributions of crustal isostasy and dynamic topography in controlling the present topography. We find that majority of the topography is compensated by the crustal structure, suggesting a topographic age that is in accord with the 400 Myr old Caledonian orogenesis. In addition, we propose that dynamic uplift of ∼300 m has rejuvenated existing topography locally in the coastal region over the last 10 Myr. Such uplift, combined with a general sea level fall, can help explain a variety of observations that have traditionally been interpreted in favor of a peneplain uplift model. We conclude that high topography along the Scandinavian margin cannot represent remnants of a peneplain uplifted within the last 20 Myr. The topography must have been high since the Caledonian orogeny.

  13. A magmatic probe of dynamic topography beneath western North America

    NASA Astrophysics Data System (ADS)

    Klöcking, M.; White, N. J.; Maclennan, J.

    2014-12-01

    A region centered on the Yellowstone hotspot and encompassing the Colorado Plateau sits at an elevation 2 km higher than the cratonic North America. This difference broadly coincides with tomographically observed variations in lithospheric thickness: ~120 km beneath western North America, ~240 km beneath the craton. Thermochronology of the Grand Canyon area, sedimentary flux to the Gulf of Mexico, and river profile inversion all suggest that regional uplift occurred in at least two separate stages. High resolution seismic tomographic models, using USArray data, have identified a ring of low velocity material beneath the edges of the Colorado Plateau. Magmatism coincides with these low velocity zones and shows distinct phases: an overall increase in volume around 40 Ma and a change from lithospheric to asthenospheric signatures around 5 Ma. Volcanism is also observed to migrate north-east with time. Here, we attempt to integrate these different observations with lithospheric thickness. A dynamic topography model of progressive lithospheric erosion over a hot mantle plume might account for uplift as well as the temporal and spatial distribution of magmatism across western North America. Thinning of the lithosphere around the edges of the Colorado Plateau in combination with the hotter mantle potential temperature of a plume could create isostatic and dynamic uplift as well as allowing for melt production. To test this model, we have analysed around 100 samples from volcanic centers across western North America by ICP-MS for rare earth elements (REE). Most of the samples are younger than 5 Ma, and all of them have previously been analysed by XRF. Using trace element ratios such as La/Yb and Nb/Y we assess depth of melting and melt fraction, respectively. In addition, we use REE inversion modelling to estimate melt fractions as a function of depth and temperature of melting. The results are compared to existing constraints on lithospheric thickness and mantle potential

  14. Global dynamic topography observations reveal limited influence of large-scale mantle flow

    NASA Astrophysics Data System (ADS)

    Hoggard, M. J.; White, N.; Al-Attar, D.

    2016-06-01

    Convective circulation of the Earth's mantle maintains some fraction of surface topography that varies with space and time. Most predictive models show that this dynamic topography has peak amplitudes of about +/-2 km, dominated by wavelengths of 104 km. Here, we test these models against our comprehensive observational database of 2,120 spot measurements of dynamic topography that were determined by analysing oceanic seismic surveys. These accurate measurements have typical peak amplitudes of +/-1 km and wavelengths of approximately 103 km, and are combined with limited continental constraints to generate a global spherical harmonic model, the robustness of which has been carefully tested and benchmarked. Our power spectral analysis reveals significant discrepancies between observed and predicted dynamic topography. At longer wavelengths (such as 104 km), observed dynamic topography has peak amplitudes of about +/-500 m. At shorter wavelengths (such as 103 km), significant dynamic topography is still observed. We show that these discrepancies can be explained if short-wavelength dynamic topography is generated by temperature-driven density anomalies within a sub-plate asthenospheric channel. Stratigraphic observations from adjacent continental margins show that these dynamic topographic signals evolve quickly with time. More rapid temporal and spatial changes in vertical displacement of the Earth's surface have direct consequences for fields as diverse as mantle flow, oceanic circulation and long-term climate change.

  15. A Tailored Computation of the Mean Dynamic Topography for a Consistent Integration into Ocean Circulation Models

    NASA Astrophysics Data System (ADS)

    Becker, S.; Losch, M.; Brockmann, J. M.; Freiwald, G.; Schuh, W.-D.

    2014-11-01

    Geostrophic surface velocities can be derived from the gradients of the mean dynamic topography—the difference between the mean sea surface and the geoid. Therefore, independently observed mean dynamic topography data are valuable input parameters and constraints for ocean circulation models. For a successful fit to observational dynamic topography data, not only the mean dynamic topography on the particular ocean model grid is required, but also information about its inverse covariance matrix. The calculation of the mean dynamic topography from satellite-based gravity field models and altimetric sea surface height measurements, however, is not straightforward. For this purpose, we previously developed an integrated approach to combining these two different observation groups in a consistent way without using the common filter approaches (Becker et al. in J Geodyn 59(60):99-110, 2012; Becker in Konsistente Kombination von Schwerefeld, Altimetrie und hydrographischen Daten zur Modellierung der dynamischen Ozeantopographie 2012). Within this combination method, the full spectral range of the observations is considered. Further, it allows the direct determination of the normal equations (i.e., the inverse of the error covariance matrix) of the mean dynamic topography on arbitrary grids, which is one of the requirements for ocean data assimilation. In this paper, we report progress through selection and improved processing of altimetric data sets. We focus on the preprocessing steps of along-track altimetry data from Jason-1 and Envisat to obtain a mean sea surface profile. During this procedure, a rigorous variance propagation is accomplished, so that, for the first time, the full covariance matrix of the mean sea surface is available. The combination of the mean profile and a combined GRACE/GOCE gravity field model yields a mean dynamic topography model for the North Atlantic Ocean that is characterized by a defined set of assumptions. We show that including the

  16. Isostatic and dynamic support of high topography on a North Atlantic passive margin

    NASA Astrophysics Data System (ADS)

    Kathrine Pedersen, Vivi; Huismans, Ritske S.; Moucha, Robert

    2016-04-01

    Substantial controversy surrounds the origin and recent evolution of high topography along passive continental margins in the North Atlantic, with suggested age of formation ranging from early Paleozoic Caledonian orogenesis to Neogene uplift of a Mesozoic peneplain. Here we focus on the well-documented high passive margin in southwestern Scandinavia, and quantify the relative contributions of crustal isostasy and dynamic topography in controlling the present topography. We find that most topography is compensated by the crustal structure, suggesting a topographic age related to ~400 Myr old Caledonian orogenesis. In addition, we infer that dynamic uplift (~300 m) has rejuvenated existing topography locally in the coastal region within the last ~10 Myr due to mantle convection. Such uplift has, in combination with a general eustatic sea-level fall and concurrent erosion-driven isostatic rock-column uplift, the potential to increase erosion of coastal-near regions and explain observations that have traditionally been interpreted in favor of the peneplain uplift model. We conclude that high topography along the Scandinavian margin cannot represent remnants of a peneplain uplifted within the last ~20 Myr. Topography must have been high since the Caledonian orogeny.

  17. Calculating gravitationally self-consistent sea level changes driven by dynamic topography

    NASA Astrophysics Data System (ADS)

    Austermann, J.; Mitrovica, J. X.

    2015-12-01

    We present a generalized formalism for computing gravitationally self-consistent sea level changes driven by the combined effects of dynamic topography, geoid perturbations due to mantle convection, ice mass fluctuations and sediment redistribution on a deforming Earth. Our mathematical treatment conserves mass of the surface (ice plus ocean) load and the solid Earth. Moreover, it takes precise account of shoreline migration and the associated ocean loading. The new formalism avoids a variety of approximations adopted in previous models of sea level change driven by dynamic topography, including the assumption that a spatially fixed isostatic amplification of `air-loaded' dynamic topography accurately accounts for ocean loading effects. While our approach is valid for Earth models of arbitrary complexity, we present numerical results for a set of simple cases in which a pattern of dynamic topography is imposed, the response to surface mass loading assumes that Earth structure varies only with depth and that isostatic equilibrium is maintained at all times. These calculations, involving fluid Love number theory, indicate that the largest errors in previous predictions of sea level change driven by dynamic topography occur in regions of shoreline migration, and thus in the vicinity of most geological markers of ancient sea level. We conclude that a gravitationally self-consistent treatment of long-term sea level change is necessary in any effort to use such geological markers to estimate ancient ice volumes.

  18. Effect of surface topography upon micro-impact dynamics

    NASA Astrophysics Data System (ADS)

    Mohammadpour, M.; Morris, N. J.; Leighton, M.; Rahnejat, H.

    2016-03-01

    Often the effect of interactions at nano-scale determines the tribological performance of load bearing contacts. This is particularly the case for lightly loaded conjunctions where a plethora of short range kinetic interactions occur. It is also true of larger load bearing conjunctions where boundary interactions become dominant. At the diminutive scale of fairly smooth surface topography the cumulative discrete interactions give rise to the dominance of boundary effects rather than the bulk micro-scale phenomena, based on continuum mechanics. The integration of the manifold localized discrete interactions into a continuum is the pre-requisite to the understanding of characteristic boundary effects, which transcend the physical length scales and affect the key observed system attributes. These are energy efficiency and vibration refinement. This paper strives to present such an approach. It is shown that boundary and near boundary interactions can be adequately described by surface topographical measures, as well the thermodynamic conditions.

  19. Dynamic scalp topography reveals neural signs just before performance errors

    PubMed Central

    Ora, Hiroki; Sekiguchi, Tatsuhiko; Miyake, Yoshihiro

    2015-01-01

    Performance errors may cause serious consequences. It has been reported that ongoing activity of the frontal control regions across trials associates with the occurrence of performance errors. However, neural mechanisms that cause performance errors remain largely unknown. In this study, we hypothesized that some neural functions required for correct outcomes are lacking just before performance errors, and to determine this lack of neural function we applied a spatiotemporal analysis to high-density electroencephalogram signals recorded during a visual discrimination task, a d2 test of attention. To our knowledge, this is the first report of a difference in the temporal development of scalp ERP between trials with error, and correct outcomes as seen by topography during the d2 test of attention. We observed differences in the signal potential in the frontal region and then the occipital region between reaction times matched with correct and error outcomes. Our observations suggest that lapses of top-down signals from frontal control regions cause performance errors just after the lapses. PMID:26289925

  20. Geoid Anomalies and Dynamic Topography from Time Dependent, Spherical Axisymmetric Mantle Convection

    NASA Technical Reports Server (NTRS)

    Kiefer, Walter S.; Kellogg, Louise H.

    1998-01-01

    Geoid anomalies and dynamic topography are two important diagnostics of mantle convection. We present geoid and topography results for several time-dependent convection models in spherical axisymmetric geometry for Rayleigh numbers between 10(exp 6) and 10(exp 7) with depth-dependent viscosity and mixtures of bottom and internal heating. The models are strongly chaotic, with boundary layer instabilities erupting out of both thermal boundary layers. In some instances, instabilities from one boundary layer influence the development of instabilities in the other boundary layer. Such coupling between events at the top and bottom of the mantle has been suggested to play a role in a mid-Cretaceous episode of enhanced volcanism in the Pacific. These boundary layer instabilities produce large temporal variations in the geoid anomalies and dynamic nd to the topography associated with the convection. The amplitudes of these fluctuations depend on the detailed model parameter,.% it of this but fluctuations of 30-50% relative to the time-averaged geoid and topography are common. The convective planform is strongly sensitive to the specific initial conditions. Convection cells with larger aspect ratio tend to have larger fractional fluctuations in their geoid and topography amplitudes, because boundary layer instabilities have more time to develop in long cells. In some instances, we observe low-amplitude topographic highs adjacent to the topographic lows produced by cold downwellings. We discuss applications of these results to several situations, including the temporal variability of m basis. hotspots such as Hawaii, the topography of subduction zone outer rises, and the topography of coronae on Venus.

  1. Landscape Response to Changes in Dynamic Topography on the U.S. Atlantic Passive Margin

    NASA Astrophysics Data System (ADS)

    Ruetenik, G.; Moucha, R.; Hoke, G. D.

    2014-12-01

    Recent global backwards-in time models of mantle convection have resulted in vastly different interpretations of the transient state of dynamic topography on the U.S. Atlantic passive margin over the past 30 Myr (Moucha et al., 2008; Spacejovic et al., 2008; Rowley et al., 2013; Liu, 2014) . A promising way of benchmarking these geodynamic models is by reconciling them with the observed offshore sedimentary record. However, it is difficult to deconvolve the erosional response produced by changes in dynamic topography from other sources of landscape change because the erosional response is a convolution of dynamic topography changes, tectonic uplift/subsidence, flexural response to erosional unloading and depositional loading, rock properties, and climate. Herein, we present results from a new landscape evolution model that is capable of producing simulations that are required at the scale and resolution necessary to quantify the landscape response to various models of dynamic topographic change on the U.S. Atlantic passive margin in the presence of flexural unloading and loading due to erosion and deposition. We perform a sensitivity study on the effects of geodynamic modeling parameters including effective elastic thickness, climate and rock properties. We find that, while models of dynamic topography are difficult to discern from the available sedimentary record at the scale of the continent in part due to induced topologic (stream geometry) change, at the catchment scale deposition rates are vastly different through time with differing dynamic topography models. At this scale, all models show distinct peaks in deposition rates, and varying elastic thickness has a significant effect on altering the timing of peak deposition.

  2. How to approximate viscoelastic dynamic topographies of stagnant lid planetary bodies?

    NASA Astrophysics Data System (ADS)

    Dumoulin, Caroline; Čadek, Ondřej; Choblet, Gaël

    2013-04-01

    Planetary mantles are viscoelastic media. However, since numerical models of thermal convection in a viscoelastic spherical shell are still very challenging, most of the studies concerning dynamic topography of planetary surfaces generated by mantle convection use one of the following simplified rheological set-up: i) IVF (instantaneous viscous flow), ii) viscous body with a free surface, or iii) hybrid methods combining viscous deformation and elastic filtering of the topography. Justifications for the use of such approximations instead of a fully viscoelastic rheology have been made on the basis of simple tests with step-like viscosity structures, with small to moderate viscosity contrasts. However, because the rheology of planetary materials is thermally activated, the radial stratification of viscosity is more likely to be a continuous function of depth, and global viscosity contrasts might be very large. In our study, we systematically compare viscoelastic dynamic topography induced by an internal load to topographies generated by the three different simplified approaches listed above using a realistic viscosity profile for a stagnant lid associated to the lithosphere of a one plate planete. To this purpose, we compute response functions of surface topography and geoid using three different semi-spectral models that all include self-gravitation: a) a linear Maxwell body with a pseudo free upper surface, b) a viscous body with a pseudo free upper surface, and c) a viscous body with a free-slip condition at the surface. Results obtained with this last model (IVF) can then be filtered using the elastic thin shell approximation: the effective elastic thickness then corresponds to the elastic thickness that is needed to fit the viscoelastic topography with an elastic filtering of the IVF topography. We show that the effective elastic thickness varies strongly with the degree of the load, with the depth of the load, and with the duration of the loading. These

  3. Dynamic topography and gravity anomalies for fluid layers whose viscosity varies exponentially with depth

    NASA Technical Reports Server (NTRS)

    Revenaugh, Justin; Parsons, Barry

    1987-01-01

    Adopting the formalism of Parsons and Daly (1983), analytical integral equations (Green's function integrals) are derived which relate gravity anomalies and dynamic boundary topography with temperature as a function of wavenumber for a fluid layer whose viscosity varies exponentially with depth. In the earth, such a viscosity profile may be found in the asthenosphere, where the large thermal gradient leads to exponential decrease of viscosity with depth, the effects of a pressure increase being small in comparison. It is shown that, when viscosity varies rapidly, topography kernels for both the surface and bottom boundaries (and hence the gravity kernel) are strongly affected at all wavelengths.

  4. Absolute and relative choreographies in rigid body dynamics

    NASA Astrophysics Data System (ADS)

    Borisov, A. V.; Kilin, A. A.; Mamaev, I. S.

    2008-06-01

    For the classical problem of motion of a rigid body about a fixed point with zero area integral, we present a family of solutions that are periodic in the absolute space. Such solutions are known as choreographies. The family includes the well-known Delone solutions (for the Kovalevskaya case), some particular solutions for the Goryachev-Chaplygin case, and the Steklov solution. The “genealogy” of solutions of the family naturally appearing from the energy continuation and their connection with the Staude rotations are considered. It is shown that if the integral of areas is zero, the solutions are periodic with respect to a coordinate frame that rotates uniformly about the vertical (relative choreographies).

  5. Noise-driven cooperative dynamics between vegetation and topography in riparian zones

    NASA Astrophysics Data System (ADS)

    Vesipa, R.; Camporeale, C.; Ridolfi, L.

    2015-10-01

    Riparian ecosystems exhibit complex biotic and abiotic dynamics, where the triad vegetation-sediments-stream determines the ecogeomorphological features of the river landscape. Random fluctuations of the water stage are a key trait of this triad, and a number of behaviors of the fluvial environment can be understood only taking into consideration the role of noise. In order to elucidate how randomness shape riparian transects, a stochastic model that takes into account the main links between vegetation, sediments, and the stream is adopted, emphasizing the capability of vegetation to alter the plot topography. A minimalistic approach is pursued, and the probability density function of vegetation biomass is analytically evaluated in any transect plot. This probability density function strongly depends on the vegetation-topography feedback. We demonstrate how the vegetation-induced modifications of the bed topography create more suitable conditions for the survival of vegetation in a stochastically dominated environment.

  6. Dynamic topography change of the eastern United States since 3 million years ago.

    PubMed

    Rowley, David B; Forte, Alessandro M; Moucha, Robert; Mitrovica, Jerry X; Simmons, Nathan A; Grand, Stephen P

    2013-06-28

    Sedimentary rocks from Virginia through Florida record marine flooding during the mid-Pliocene. Several wave-cut scarps that at the time of deposition would have been horizontal are now draped over a warped surface with a maximum variation of 60 meters. We modeled dynamic topography by using mantle convection simulations that predict the amplitude and broad spatial distribution of this distortion. The results imply that dynamic topography and, to a lesser extent, glacial isostatic adjustment account for the current architecture of the coastal plain and proximal shelf. This confounds attempts to use regional stratigraphic relations as references for longer-term sea-level determinations. Inferences of Pliocene global sea-level heights or stability of Antarctic ice sheets therefore cannot be deciphered in the absence of an appropriate mantle dynamic reference frame. PMID:23686342

  7. Topographies and dynamics on multidimensional potential energy surfaces

    NASA Astrophysics Data System (ADS)

    Ball, Keith Douglas

    The stochastic master equation is a valuable tool for elucidating potential energy surface (PES) details that govern structural relaxation in clusters, bulk systems, and protein folding. This work develops a comprehensive framework for studying non-equilibrium relaxation dynamics using the master equation. Since our master equations depend upon accurate partition function models for use in Rice-Ramsperger-Kassel-Marcus (RRK(M) transition state theory, this work introduces several such models employing various harmonic and anharmonic approximations and compares their predicted equilibrium population distributions with those determined from molecular dynamics. This comparison is performed for the fully-delineated surfaces (KCl)5 and Ar9 to evaluate model performance for potential surfaces with long- and short-range interactions, respectively. For each system, several models perform better than a simple harmonic approximation. While no model gives acceptable results for all minima, and optimal modeling strategies differ for (KCl)5 and Ar9, a particular one-parameter model gives the best agreement with simulation for both systems. We then construct master equations from these models and compare their isothermal relaxation predictions for (KCl)5 and Ar9 with molecular dynamics simulations. This is the first comprehensive test of the kinetic performance of partition function models of its kind. Our results show that accurate modeling of transition-state partition functions is more important for (KCl)5 than for Ar9 in reproducing simulation results, due to a marked stiffening anharmonicity in the transition-state normal modes of (KCl)5. For both systems, several models yield qualitative agreement with simulation over a large temperature range. To examine the robustness of the master equation when applied to larger systems, for which full topographical descriptions would be either impossible or infeasible, we compute relaxation predictions for Ar11 using a master equation

  8. Slab flattening, dynamic topography and normal faulting in the Cordillera Blanca region (northern Peru)

    NASA Astrophysics Data System (ADS)

    Margirier, A.; Robert, X.; Laurence, A.; Gautheron, C.; Bernet, M.; Simon-Labric, T.; Hall, S. R.

    2015-12-01

    Processes driving surface uplift in the Andes are still debated and the role of subduction processes as slab flattening on surface uplift and relief building in the Andes is not well understood. Some of the highest Andean summits, the Cordillera Blanca (6768 m) and the Cordillera Negra (5187 m), are located above a present flat subduction zone (3-15°S), in northern Peru. In this area, both the geometry and timing of the flattening of the slab are well constrained (Gutscher et al., 1999; Rosenbaum et al., 2005). This region is thus a perfect target to explore the effect of slab flattening on the Andean topography and uplift. We obtained new apatite (U-Th)/He and fission-track ages from three vertical profiles located in the Cordillera Blanca and the Cordillera Negra. Time-temperature paths obtained from inverse modeling of the thermochronological data indicates a Middle Miocene cooling for both Cordillera Negra profiles. We interpret it as regional exhumation in the Cordillera Occidental starting in Middle Miocene, synchronous with the onset of the subduction of the Nazca ridge (Rosenbaum et al., 2005). We propose that the Nazca ridge subduction at 15 Ma and onset of slab flattening in northern Peru drove regional positive dynamic topography and thus enhanced exhumation in the Cordillera Occidental. This study provides new evidence of the impact subduction processes and associated dynamic topography on paleogeography and surface uplift in the Andes.

  9. Dynamic frequency-domain interferometer for absolute distance measurements with high resolution

    SciTech Connect

    Weng, Jidong; Liu, Shenggang; Ma, Heli; Tao, Tianjiong; Wang, Xiang; Liu, Cangli; Tan, Hua

    2014-11-15

    A unique dynamic frequency-domain interferometer for absolute distance measurement has been developed recently. This paper presents the working principle of the new interferometric system, which uses a photonic crystal fiber to transmit the wide-spectrum light beams and a high-speed streak camera or frame camera to record the interference stripes. Preliminary measurements of harmonic vibrations of a speaker, driven by a radio, and the changes in the tip clearance of a rotating gear wheel show that this new type of interferometer has the ability to perform absolute distance measurements both with high time- and distance-resolution.

  10. Noise-driven cooperative dynamics between vegetation and topography in riparian zones

    NASA Astrophysics Data System (ADS)

    Vesipa, Riccardo; Camporeale, Carlo; Ridolfi, Luca

    2016-04-01

    Riparian ecosystems exhibit complex biotic and abiotic dynamics, where the triad vegetation-sediments-stream determines the eco-geomorphological features of the river landscape. Random fluctuations of the water stage are a key trait of this triad, and a number of behaviors of the fluvial environment can be understood only taking into consideration the role of noise. In fact, in a given plot, vegetation biomass can grow (if the stage is below the plot elevation) or decay (if the stage is above the plot elevation). As a result, biomass exhibits significant temporal variations. In this framework, the capability of vegetation to alter the transect topography (namely, the plot elevation) is crucial. Vegetation can increase the plot elevation by a number of mechanisms (trapping of water- and wind-transported sediment particles, production of organic soil, stabilization of the soil surface). The increment of plot elevation induces the reduction of the plot-specific magnitude, frequency and duration of floods. These more favorable plot-specific hydrological conditions, in turn, induce an increment of biomass. Moreover, the higher the vegetation biomass, the higher the plot elevation increment induced by these mechanisms. In order to elucidate how the stochastically varying water stage and the vegetation-induced topographic alteration shape the bio-morphological characteristics of riparian transects, a stochastic model that takes into account the main links between vegetation, sediments and the stream was adopted. In particular, the capability of vegetation to alter the plot topography was emphasized. In modeling such interactions, the minimalistic approach was pursued. The complex vegetation-sediments-stream interactions were modeled by a set of state-depended stochastic eco-hydraulic equations. The probability density function of vegetation biomass was then analytically evaluated in any transect plot. This pdf strongly depends on the vegetation-topography feedback. We

  11. Frequency-scanning interferometry for dynamic absolute distance measurement using Kalman filter.

    PubMed

    Tao, Long; Liu, Zhigang; Zhang, Weibo; Zhou, Yangli

    2014-12-15

    We propose a frequency-scanning interferometry using the Kalman filtering technique for dynamic absolute distance measurement. Frequency-scanning interferometry only uses a single tunable laser driven by a triangle waveform signal for forward and backward optical frequency scanning. The absolute distance and moving speed of a target can be estimated by the present input measurement of frequency-scanning interferometry and the previously calculated state based on the Kalman filter algorithm. This method not only compensates for movement errors in conventional frequency-scanning interferometry, but also achieves high-precision and low-complexity dynamic measurements. Experimental results of dynamic measurements under static state, vibration and one-dimensional movement are presented. PMID:25503050

  12. Deployment dynamics of a simplified spinning IKAROS solar sail via absolute coordinate based method

    NASA Astrophysics Data System (ADS)

    Zhao, Jiang; Tian, Qiang; Hu, Hai-Yan

    2013-02-01

    The spinning solar sail of large scale has been well developed in recent years. Such a solar sail can be considered as a rigid-flexible multibody system mainly composed of a spinning central rigid hub, a number of flexible thin tethers, sail membranes, and tip masses. A simplified interplanetary kite-craft accelerated by radiation of the Sun (IKAROS) model is established in this study by using the absolute-coordinate-based (ACB) method that combines the natural coordinate formulation (NCF) describing the central rigid hub and the absolute nodal coordinate formulation (ANCF) describing flexible parts. The initial configuration of the system in the second-stage deployment is determined through both dynamic and static analyses. The huge set of stiff equations of system dynamics is solved by using the generalized-alpha method, and thus the deployment dynamics of the system can be well understood.

  13. Dynamic Passage of Topography Beneath the Southern Costa Rica Forearc seen with Seismic Stratigraphy

    NASA Astrophysics Data System (ADS)

    Edwards, J. H.; Kluesner, J. W.; Silver, E. A.

    2014-12-01

    3D seismic reflection data (CRISP) collected across the southern Costa Rica margin reveals that a thick, deforming sedimentary wedge underlies the younger slope sediments (Silver et al., this meeting). The older wedge material and younger slope sediments are separated by a high-amplitude regional unconformity. Seismic stratigraphy of the sedimentary strata overlying this regional unconformity reflects a dynamic deformation history of the margin. The younger slope sediments contain series of more localized unconformities, separating sedimentary units as thick as 1 km that reveal a dynamically changing set of inverted, overlapping basins. The geometry of these overlapping, inverted basins indicate sequential uplift events. The direction of basin thickening varies upsection, and these basins are cut by both thrust and normal faults and are deformed by folding. Structural development appears to be controlled by relief on the subducting plate interface, which induces uplift and subsidence and thereby controls the pattern of erosion and deposition. We interpret the evolution of these inverted stratigraphic packages as forming from subducting topography. Correlating these seismic-stratigraphic packages to recent drilling based on preliminary magnetostratigraphy from IODP site U1413 (Expedition 344 Scientists, 2013), allows us to date the passage of the subducting plate topography beginning ~2 Ma.

  14. Dynamic topography of visual evoked potentials and extrageniculate projection in case of Riddoch phenomenon.

    PubMed

    Tsutsui, J; Ichihashi, K; Kimura, H

    1984-01-01

    A 34-year-old woman showing the Riddoch phenomenon was studied by the technique of dynamic topography of visual evoked potential (VEP). This case had cortical blindness which developed during the process of massive intestinal hemorrhage, shock and surgery. The visual acuity was limited to hand movement, and perception of white and colored light was present, but there was no form recognition. Tracking eye movement for a flashlight was possible and optokinetic nystagmus (OKN) also appeared. CT-scan showed a diffuse low density area in the white matter of the occipital lobe. The VEPs by flash and a checkerboard of 60'-100' were detectable. Dynamic topography of the VEP showed that a strong negative deflection from the brainstem appeared at around 30 msec and this deflection expanded to the parietal region at about 90 msec. Subsequently, a positive deflection extending from the frontal region to the occipital region continued at 100 msec to 150 msec. Such a process of reaction is not observed in the normal subject. These findings suggest that the visual reaction was conducted abnormally through the extrageniculate system; from the brainstem to the parietal area and then to the occipital area. PMID:6748358

  15. Flight dynamics facility operational orbit determination support for the ocean topography experiment

    NASA Technical Reports Server (NTRS)

    Bolvin, D. T.; Schanzle, A. F.; Samii, M. V.; Doll, C. E.

    1991-01-01

    The Ocean Topography Experiment (TOPEX/POSEIDON) mission is designed to determine the topography of the Earth's sea surface across a 3 yr period, beginning with launch in June 1992. The Goddard Space Flight Center Dynamics Facility has the capability to operationally receive and process Tracking and Data Relay Satellite System (TDRSS) tracking data. Because these data will be used to support orbit determination (OD) aspects of the TOPEX mission, the Dynamics Facility was designated to perform TOPEX operational OD. The scientific data require stringent OD accuracy in navigating the TOPEX spacecraft. The OD accuracy requirements fall into two categories: (1) on orbit free flight; and (2) maneuver. The maneuver OD accuracy requirements are of two types; premaneuver planning and postmaneuver evaluation. Analysis using the Orbit Determination Error Analysis System (ODEAS) covariance software has shown that, during the first postlaunch mission phase of the TOPEX mission, some postmaneuver evaluation OD accuracy requirements cannot be met. ODEAS results also show that the most difficult requirements to meet are those that determine the change in the components of velocity for postmaneuver evaluation.

  16. Separation of dynamic and isostatic components of the Venusian gravity and topography and determination of the crustal thickness of Venus

    NASA Astrophysics Data System (ADS)

    Yang, An; Huang, Jinshui; Wei, Daiyun

    2016-09-01

    Assuming that the long-wavelength geoid and topography of Venus are supported by both mantle convection and Airy isostasy, we propose a method to separate the dynamic and isostatic components of the Venusian gravity and topography with the aid of the dynamic admittance from numerical models of mantle convection and the isostatic admittance from an Airy isostatic model. The global crustal thickness is then calculated based on the isostatic component of the gravity and topography. The results show that some highland plateaus such as Ishtar Terra and Ovda Regio have thick crust, which are largely supported by isostatic compensation. Other highland plateaus such as Thetis and Phoebe Regiones appear to have superimposed contributions from crustal thickening and dynamic support. Volcanic rises such as Atla and Beta Regiones have thin crust, which is consistent with the postulation that these volcanic rises are mainly the products of dynamic uplift caused by mantle plumes.

  17. Modelling and Estimation of Dynamic Ocean Topography Within Global Geopotential Solutions

    NASA Technical Reports Server (NTRS)

    Lemoine, Frank G.; Pavlis, Nikolaos; Wang, Y. M.; Cox, C. M.

    1998-01-01

    In this poster, we will present a report on the ongoing investigation "Improved Gravitational and Dynamic Height Models Through the use of Oceanographic Data." we have used a two year mean (1993-1994) of the Dynamic ocean Topography (DOT) field implied by the Semtner and Chervin POCM_4B model, and developed normal equations in surface spherical harmonics to degree and order 30. These normal equations, were combined with normal equations derived from TOPEX and ERS-1 altimeter data over the same time period. Combination solutions (based on satellite tracking data, altimeter data, surface gravity data and OCM data) were were developed Test solutions were obtained estimating the DOT field to 2Ox2O and 3ox3O. These solutions were tested with independent DOT values computed over 38 WOCE hydrographic sections, which contained a total of 3072 stations and represented 216000 km of travelled lines. The weighted standard deviation of the differences between the DOT obtained from the hydrographic data and and the field estimated from the joint combination solutions was computed for each of the test models, the weighted standard deviation for the baseline combination solution excluding the POCM4_B data was 9.7 cm for a DOT solution to 30x30, where introducing the POCM4_B data into the combination model reduced the standard deviation to 9.2 cm, indicating the the introduction of oceanographic information benefits the solution for the dynamic ocean topography. We will discuss the weighting schemes applied and the method of solution. Another aspect of our investigation involves testing alternate parametric representations of the dynamic height field. We looked at the alternative representations in terms of the Proudman functions (PF), and compared these to the use of spherical harmonics (SH) to represent the dynamic ocean topography, using once again the 1993 and 1994 output of the POCM4_B OCM as the reference model. A significant advantage of PF's over SH's is that the former

  18. Lithosphere Structure in Southern Africa: Mantle Density, Dynamic Topography, Moho Sharpness, and Kimberlite Magmatism

    NASA Astrophysics Data System (ADS)

    Artemieva, I. M.; Vinnik, L. P.

    2015-12-01

    In southern Africa, both the Archean and Proterozoic blocks have the topography 500-700 m higher than in any other craton worldwide, except for the Tanzanian craton. An unusually high topography may be caused by a low density of the cratonic lithospheric mantle and/or by the dynamic support of the mantle with origin below the depth of isostatic compensation (assumed to be at the lithosphere base). We use free-board constraints to examine the relative contributions of the both factors to surface topography in the cratons of southern Africa and present regional model of density structure of the lithospheric mantle. The results indicate that 0.5-1.0 km of topography requires the dynamic contribution from the sublithospheric mantle because it cannot be explained by the lithosphere structure within the petrologically permitted range of mantle densities. The calculated lithospheric mantle density values are in an overall agreement with xenolith-based data and show an overall trend in mantle density increase from Archean to younger lithospheric terranes. Notable exceptions are the Limpopo belt and the Bushveld Intrusion Complex, which have an increased mantle density, probably as a result of melt-metasomatism. The Western Cape Fold Belt has a moderately depleted mantle with density within the range expected for Phanerozoic mantle, while mantle densities beneath the Eastern Cape Fold Belt require the presence of a significant amount of eclogite in the mantle. Mantle density structure correlates with distribution of kimberlites and with seismic velocity contrast across the Moho: kimberlite-rich regions have sharp Moho and low-density (3.32-3.33 g/cc) mantle, while kimberlite-poor regions have transient Moho and denser mantle (3.34-3.35 g/cc). We explain this pattern by melt-metasomatism which affects both mantle depletion and the Moho sharpness. We also find that regions with high mantle density host non-diamondiferous kimberlites, while diamondiferous kimberlites are

  19. The eustatic chimera: isn't the Cenomanian maximum flood a dynamic topography puzzle?

    NASA Astrophysics Data System (ADS)

    Ostanciaux, E.; Robin, C.; Guillocheau, F.; Trotin, G.; Husson, L.

    2012-04-01

    More and more, dynamic topography is predicted to seriously control sea level, which challenges the concept of eustasy, but field evidence are sparse. In order to evaluate the space and time evolution of relative sea level variations, we made paleogeographic reconstructions for three consecutive stages around the presumed Cenomanian maximum flood. For that purpose, we compiled stratigraphic charts and existing paleogeographic maps to reconstruct shorelines at a global scale and infer transgressive and regressive phases. The Cenomanian transgressive phase is essentially present around the Tethys, whereas regression prevails at higher latitudes. Furthermore, diachronicity accompanies the presumed sea level high, for the trend reverses between the three stages in the northern hemisphere while it further subsides in the southern one. These reconstructions therefore suggest that an evolving degree two structure of uplift and subsidence may be more endemic of this period than uniform sea level change and thus, they better recall internal dynamics than eustasy. Indeed, flooding accompanies the Tethyan subduction zone, while regressions are located above spreading oceans. We interpret relative sea level change during the late Cretaceous as the traces of the negative dynamic subsidence above the Tehyan slab in the one hand, and in the other hand of the superplumes (African in particular) that lead to the breakup of the Atlantic. We further confront our results to the predictions of Steinberger, who provides estimates of dynamic topography since the latest Albian. We conformably observe, for instance, positive anomalies in North America, in the Baltic area, or in South Africa, but the model mostly fails to predict the observe diachronicity in vertical ground motion.

  20. Dynamic sea surface topography, gravity and improved orbit accuracies from the direct evaluation of SEASAT altimeter data

    NASA Technical Reports Server (NTRS)

    Marsh, J. G.; Lerch, F.; Koblinsky, C. J.; Klosko, S. M.; Robbins, J. W.; Williamson, R. G.; Patel, G. B.

    1989-01-01

    A method for the simultaneous solution of dynamic ocean topography, gravity and orbits using satellite altimeter data is described. A GEM-T1 based gravitational model called PGS-3337 that incorporates Seasat altimetry, surface gravimetry and satellite tracking data has been determined complete to degree and order 50. The altimeter data is utilized as a dynamic observation of the satellite's height above the sea surface with a degree 10 model of dynamic topography being recovered simultaneously with the orbit parameters, gravity and tidal terms in this model. PGS-3337 has a geoid uncertainty of 60 cm root-mean-square (RMS) globally, with the uncertainty over the altimeter tracked ocean being in the 25 cm range. Doppler determined orbits for Seasat, show large improvements, with the sub-30 cm radial accuracies being achieved. When altimeter data is used in orbit determination, radial orbital accuracies of 20 cm are achieved. The RMS of fit to the altimeter data directly gives 30 cm fits for Seasat when using PGS-3337 and its geoid and dynamic topography model. This performance level is two to three times better than that achieved with earlier Goddard earth models (GEM) using the dynamic topography from long-term oceanographic averages. The recovered dynamic topography reveals the global long wavelength circulation of the oceans with a resolution of 1500 km. The power in the dynamic topography recovery is now found to be closer to that of oceanographic studies than for previous satellite solutions. This is attributed primarily to the improved modeling of the geoid which has occurred. Study of the altimeter residuals reveals regions where tidal models are poor and sea state effects are major limitations.

  1. Multiscale Reactive Molecular Dynamics for Absolute pK a Predictions and Amino Acid Deprotonation.

    PubMed

    Nelson, J Gard; Peng, Yuxing; Silverstein, Daniel W; Swanson, Jessica M J

    2014-07-01

    Accurately calculating a weak acid's pK a from simulations remains a challenging task. We report a multiscale theoretical approach to calculate the free energy profile for acid ionization, resulting in accurate absolute pK a values in addition to insights into the underlying mechanism. Importantly, our approach minimizes empiricism by mapping electronic structure data (QM/MM forces) into a reactive molecular dynamics model capable of extensive sampling. Consequently, the bulk property of interest (the absolute pK a) is the natural consequence of the model, not a parameter used to fit it. This approach is applied to create reactive models of aspartic and glutamic acids. We show that these models predict the correct pK a values and provide ample statistics to probe the molecular mechanism of dissociation. This analysis shows changes in the solvation structure and Zundel-dominated transitions between the protonated acid, contact ion pair, and bulk solvated excess proton. PMID:25061442

  2. Anomalous Subsidence at Rifted Continental Margins: Distinguishing Mantle Dynamic Topography from Anomalous Oceanic Crustal Thickness

    NASA Astrophysics Data System (ADS)

    Cowie, L.; Kusznir, N. J.

    2012-12-01

    It has been proposed that some continental rifted margins have anomalous subsidence histories and that at breakup they were elevated at shallower bathymetries than the isostatic response of classical rift models (McKenzie 1978) would predict. The existence of anomalous syn or post breakup subsidence of this form would have important implications for our understanding of the geodynamics of continental breakup and rifted continental margin formation, margin subsidence history and the evolution of syn and post breakup depositional systems. We have investigated three rifted continental margins; the Gulf of Aden, Galicia Bank and the Gulf of Lions, to determine whether the oceanic crust in the ocean-continent transition of these margins has present day anomalous subsidence and if so, whether it is caused by mantle dynamic topography or anomalous oceanic crustal thickness. Residual depth anomalies (RDA) corrected for sediment loading, using flexural backstripping and decompaction, have been calculated by comparing observed and age predicted oceanic bathymetries in order to identify anomalous oceanic bathymetry and subsidence at these margins. Age predicted bathymetric anomalies have been calculated using the thermal plate model predictions from Crosby & McKenzie (2009). Non-zero sediment corrected RDAs may result from anomalous oceanic crustal thickness with respect to the global average, or from mantle dynamic uplift. Positive RDAs may result from thicker than average oceanic crust or mantle dynamic uplift; negative RDAs may result from thinner than average oceanic crust or mantle dynamic subsidence. Gravity inversion incorporating a lithosphere thermal gravity anomaly correction and sediment thickness from 2D seismic data has been used to determine Moho depth and oceanic crustal basement thickness. The reference Moho depths used in the gravity inversion have been calibrated against seismic refraction Moho depths. The gravity inversion crustal basement thicknesses

  3. Age distributions and dynamically changing hydrologic systems: Exploring topography-driven flow

    NASA Astrophysics Data System (ADS)

    Gomez, J. D.; Wilson, J. L.

    2013-03-01

    Natural systems are driven by dynamic forcings that change in time as well as space, behavior that is inherited by the system flow field and results in time-varying age distributions (ADs). This work presents a review of the mathematical tools and solution approaches used to model ADs in dynamic time-varying flow systems. A simple conceptual, numerical model is then used to explore the role of flow dynamics in ADs for topography-driven flow systems. This model is an analog for regional groundwater systems and hyporheic zones. This model demonstrates that relatively small fluctuations in the forcing, even though importantly affecting the flow in the system, can have minimal effects in ADs. However, as the intensity of fluctuation increases, still within the bounds observed in natural systems, ADs in shallow parts of the system become highly sensitive to dynamic flow conditions, leading to considerable changes in the moments and modality of the distributions with time. In particular, transient flow can lead to emergence of new modes in the AD, which would not be present under steady flow conditions. The discrepancy observed between ADs under steady and transient flow conditions is explained by enhancement of mixing due to temporal variations in the flow field. ADs in deeper parts of the system are characterized by multimodality and tend to be more stable over time even for large forcing fluctuations.

  4. The Effect of Surface Topography on the Nonlinear Dynamics of Rossby Waves

    NASA Technical Reports Server (NTRS)

    Abarzhi, S. I.; Desjardins, O.; Pitsch, H.

    2003-01-01

    Boussinesq convection in rotating systems attracts a sustained attention of the fluid dynamics community, because it has intricate non-linear dynamics (Cross & Hohenberg 1993) and plays an important role in geophysical and astrophysical applications, such as the motion of the liquid outer core of Earth, the Red Spot in Jupiter, the giant cells in the Sun etc. (Alridge et al. 1990). A fundamental distinction between the real geo- and astrophysical problems and the idealized laboratory studies is that natural systems are inhomogeneous (Alridge et al. 1990). Heterogeneities modulate the flow and influence significantly the dynamics of convective patterns (Alridge et al. 1990; Hide 1971). The effect of modulations on pattern formation and transition to turbulence in Boussinesq convection is far from being completely understood (Cross & Hohenberg 1993; Aranson & Kramer 2002). It is generally accepted that in the liquid outer core of the Earth the transport of the angular momentum and internal heat occurs via thermal Rossby waves (Zhang et al. 2001; Kuang & Bloxham 1999). These waves been visualized in laboratory experiments in rotating liquid-filled spheres and concentric spherical shells (Zhang et al. 2001; Kuang & Bloxham 1999). The basic dynamical features of Rossby waves have been reproduced in a cylindrical annulus, a system much simpler than the spherical ones (Busse & Or 1986; Or & Busse 1987). For convection in a cylindrical annulus, the fluid motion is two-dimensional, and gravity is replaced by a centrifugal force, (Busse & Or 1986; Or & Busse 1987). Hide (1971) has suggested that the momentum and heat transport in the core might be influenced significantly by so-called bumps, which are heterogeneities on the mantle-core boundary. To model the effect of surface topography on the transport of momentum and energy in the liquid outer core of the Earth, Bell & Soward (1996), Herrmann & Busse (1998) and Westerburg & Busse (2001) have studied the nonlinear dynamics

  5. Advances in large-scale ocean dynamics from a decade of satellite altimetric measurement of ocean surface topography

    NASA Technical Reports Server (NTRS)

    Fu, L. L.; Menard, Y.

    2002-01-01

    The past decade has seen the most intensive observations of the global ocean surface topography from satellite altimeters. The Joint U.S./France TOPEX/Poseidon (T/P) Mission has become the longest radar mission ever flown in space, providing the most accurate measurements for the study of ocean dynamics since October 1992.

  6. Mantle flow and dynamic topography associated with slab window opening: Insights from laboratory models

    NASA Astrophysics Data System (ADS)

    Guillaume, Benjamin; Moroni, Monica; Funiciello, Francesca; Martinod, Joseph; Faccenna, Claudio

    2010-12-01

    We present dynamically self-consistent mantle-scale laboratory models that have been conducted to improve our understanding of the influence of slab window opening on subduction dynamics, mantle flow and associated dynamic topography over geological time scales. The adopted setup consists of a two-layer linearly viscous system simulating the subduction of a fixed plate of silicone (lithosphere) under negative buoyancy in a viscous layer of glucose syrup (mantle). Our experimental setting is also characterized by a constant-width rectangular window located at the center of a laterally confined slab, modeling the case of the interaction of a trench-parallel spreading ridge with a wide subduction zone. We found that the opening of a slab window does not produce consistent changes of the geometry and the kinematics of the slab. On the contrary, slab-induced mantle circulation, quantified both in the vertical and horizontal sections using the Feature Tracking image analysis technique, is strongly modified. In particular, rollback subduction and the opening of the slab window generate a complex mantle circulation pattern characterized by the presence of poloidal and toroidal components, with the importance of each evolving according to kinematic stages. Mantle coming from the oceanic domain floods through the slab window, indenting the supra-slab mantle zone and producing its deformation without any mixing between mantle portions. The opening of the slab window and the upwelling of sub-slab mantle produce a regional-scale non-isostatic topographic uplift of the overriding plate that would correspond to values ranging between ca. 1 and 5 km in nature. Assuming that our modeling results can be representative of the natural behavior of subduction zones, we compared them to the tectonics and volcanism of the Patagonian subduction zone. We found that the anomalous backarc volcanism that has been developing since the middle Miocene could result from the lateral flow of sub

  7. Complex dynamic substrate control: Dual-tone hydrogel photoresists allow double-dissociation of topography and modulus

    PubMed Central

    Xue, Changying; Wong, Darice

    2014-01-01

    Hydrogels are widely utilized as artificial extracellular matrices, but current materials are unable to completely recapitulate the geometric, mechanical and dynamic characteristics of natural tissues. Here, we report an approach to dynamically tune both topography and elasticity in a single photoresponsive hydrogel substrate. Upon exposure to spatially controlled doses of light, a topographically and mechanically micropatterned surface forms. Atomic force microscopy was used to investigate changes in topographical feature size and elastic moduli of the hydrogel surface as a function of irradiation time and wavelength. These photodegradable hydrogels can act as both positive and pseudo-negative photoresists, depending on exposure time and wavelength. By carefully controlling the aspect ratio (surface area to depth) of micropatterned features, unique swelling-induced ordered microstructures can be formed on the surface. These dual-tone hydrogel photoresists therefore allow dynamic tunability in both topography and elasticity, enabling the fabrication of complex and anisotropic biomaterials. PMID:24339260

  8. Contact dynamics of elasto-plastic thin beams simulated via absolute nodal coordinate formulation

    NASA Astrophysics Data System (ADS)

    Wang, Qing-Tao; Tian, Qiang; Hu, Hai-Yan

    2015-12-01

    Under the frame of multibody dynamics, the contact dynamics of elasto-plastic spatial thin beams is numerically studied by using the spatial thin beam elements of absolute nodal coordinate formulation (ANCF). The internal force of the elasto-plastic spatial thin beam element is derived under the assumption that the plastic strain of the beam element depends only on its longitudinal deformation. A new body-fixed local coordinate system is introduced into the spatial thin beam element of ANCF for efficient contact detection in the contact dynamics simulation. The linear isotropic hardening constitutive law is used to describe the elasto-plastic deformation of beam material, and the classical return mapping algorithm is adopted to evaluate the plastic strains. A multi-zone contact approach of thin beams previously proposed by the authors is also introduced to detect the multiple contact zones of beams accurately, and the penalty method is used to compute the normal contact force of thin beams in contact. Four numerical examples are given to demonstrate the applicability and effectiveness of the proposed elasto-plastic spatial thin beam element of ANCF for flexible multibody system dynamics.

  9. Contact dynamics of elasto-plastic thin beams simulated via absolute nodal coordinate formulation

    NASA Astrophysics Data System (ADS)

    Wang, Qing-Tao; Tian, Qiang; Hu, Hai-Yan

    2016-06-01

    Under the frame of multibody dynamics, the contact dynamics of elasto-plastic spatial thin beams is numerically studied by using the spatial thin beam elements of absolute nodal coordinate formulation (ANCF). The internal force of the elasto-plastic spatial thin beam element is derived under the assumption that the plastic strain of the beam element depends only on its longitudinal deformation. A new body-fixed local coordinate system is introduced into the spatial thin beam element of ANCF for efficient contact detection in the contact dynamics simulation. The linear isotropic hardening constitutive law is used to describe the elasto-plastic deformation of beam material, and the classical return mapping algorithm is adopted to evaluate the plastic strains. A multi-zone contact approach of thin beams previously proposed by the authors is also introduced to detect the multiple contact zones of beams accurately, and the penalty method is used to compute the normal contact force of thin beams in contact. Four numerical examples are given to demonstrate the applicability and effectiveness of the proposed elasto-plastic spatial thin beam element of ANCF for flexible multibody system dynamics.

  10. GOCE++ Dynamical Coastal Topography and tide gauge unification using altimetry and GOCE.

    NASA Astrophysics Data System (ADS)

    Baltazar Andersen, Ole; Knudsen, Per; Nielsen, Karina; Hughes, Chris; Woodworth, Phil; Woppelmann, Guy; Gravelle, Mederic; Bingham, Rory; Fenoblio, Luciana; Kern, Michael

    2016-04-01

    ESA has recently released a study on the potential of ocean levelling as a novel approach to the study of height system unification taking the recent development in geoid accuracy trough GOCE data into account. The suggested investigation involves the use of measurements and modelling to estimate Mean Dynamic Topography (MDT) of the ocean along a coastline which contributes/requires reconciling altimetry, tide gauge and vertical land motion. The fundamental use of the MDT computed using altimetry, ocean models or through the use of tide gauges has values of between -2 and +1 meters at different points in the ocean. However, close to the coast the determination of the MDT is problematic due to i.e., the altimeter footprint, land motion or parameterization/modelling of coastal currents. The objective of this activity is to perform a consolidated and improved understanding and modelling of coastal processes and physics responsible for sea level changes on various temporal/spatial scales. The study runs from October 2015 to march 2017 and involves elements like: Develop an approach to estimate a consistent DT at tide gauges, coastal areas, and open ocean; Validate the approach in well-surveyed areas where DT can be determined at tide gauges; Determine a consistent MDT using GOCE with consistent error covariance fields; Connect measurements of a global set of tide gauges and investigate trends

  11. New clinical instrument for the early detection of cataract using dynamic light scattering and corneal topography

    NASA Astrophysics Data System (ADS)

    Ansari, Rafat R.; Datiles, Manuel B., III; King, James F.

    2000-06-01

    A growing cataract can be detected at the molecular level using the technique of dynamic light scattering (DLS). However, the success of this method in clinical use depends upon the precise control of the scattering volume inside a patient's eye and especially during patient's repeat visits. This is important because the scattering volume (cross-over region between the scattered light and incident light) inside the eye in a high-quality DLS set-up is very small (few microns in dimension). This precise control holds the key for success in the longitudinal studies of cataract and during anti-cataract drug screening. We have circumvented these problems by fabricating a new DLS fiber optic probe with a working distance of 40 mm and by mounting it inside a cone of a corneal analyzer. This analyzer is frequently used in mapping the corneal topography during PRK (photorefractive keratectomy) and LASIK (laser in situ keratomileusis) procedures in shaping of the cornea to correct myopia. This new instrument and some preliminary clinical tests on one of us (RRA) showing the data reproducibility are described.

  12. Geopotential Model Improvement Using POCM_4B Dynamic Ocean Topography Information: PGM2000A

    NASA Technical Reports Server (NTRS)

    Pavlis, N. K.; Chinn, D. S.; Cox, C. M.; Lemoine, Frank G.; Smith, David E. (Technical Monitor)

    2000-01-01

    The two-year mean (1993-1994) Dynamic Ocean Topography (DOT) field implied by the POCM_4B circulation model was used to develop normal equations for DOT, in a surface spherical harmonic representation. These normal equations were combined with normal equations from satellite tracking data, surface gravity data, and altimeter data from TOPEX/Poseidon and ERS-1. Several least-squares combination solutions were developed in this fashion, by varying parameters such as the maximum degree of the estimated DOT and the relative weights of the different data. The solutions were evaluated in terms of orbit fit residuals, GPS/Leveling-derived undulations, and independent DOT information from in situ WOCE hydrographic data. An optimal solution was developed in this fashion which was originally presented at the 1998 EGS meeting in Nice, France. This model, designated here PGM2000A, maintains the orbit and land geoid modeling performance of EGM96, while improving its marine geoid modeling capability. In addition, PGM2000A's error spectrum is considerably more realistic than those of other contemporary gravitational models and agrees well with the error spectrum of EGM96. We will present the development and evaluation of PGM2000A, with particular emphasis on the weighting of the DOT information implied by POCM_4B. We will also present an inter-comparison of PGM2000A with the GRIM5-C1 and TEG-4 models. Directions for future work and problematic areas will be identified.

  13. Global mean dynamic topography based on GOCE data and Wiener filters

    NASA Astrophysics Data System (ADS)

    Gilardoni, Maddalena; Reguzzoni, Mirko; Albertella, Alberta

    2015-04-01

    A mean dynamic ocean topography (MDT) has been computed by using a GOCE-only gravity model and a given mean sea surface (MSS) obtained from satellite altimetry. Since the used gravity model, i.e. the fifth release of the time-wise solution covering the full mission lifetime, is truncated at a maximum harmonic degree of 280, the obtained MDT has to be consistently filtered. This has been done globally by using the spherical harmonic representation and following a Wiener minimization principle. This global filtering approach is convenient from the computational point of view but requires to have MDT values all over the Earth surface and therefore to fill the continents with fictitious data. The main improvements with respect to the already presented results are in the MDT filling procedure (to guarantee that the global signal has the same covariance of the one over the oceans), in the error modelling of the input MSS and in the error estimation of the filtered MDT and of the corresponding geostrophic velocities. The impact of GOCE data in the ocean circulation global modelling has been assessed by comparing the pattern of the obtained geostrophic currents with those computed by using EGM2008. Comparisons with independent circulation data based on drifters and other MDT models have been also performed with the aim of evaluating the accuracy of the obtained results.

  14. Video Animation of Ocean Topography From TOPEX/POSEIDON

    NASA Technical Reports Server (NTRS)

    Fu, Lee-Lueng; Leconte, Denis; Pihos, Greg; Davidson, Roger; Kruizinga, Gerhard; Tapley, Byron

    1993-01-01

    Three video loops showing various aspects of the dynamic ocean topography obtained from the TOPEX/POSEIDON radar altimetry data will be presented. The first shows the temporal change of the global ocean topography during the first year of the mission. The time-averaged mean is removed to reveal the temporal variabilities. Temporal interpolation is performed to create daily maps for the animation. A spatial smoothing is also performed to retain only the large-sale features. Gyre-scale seasonal changes are the main features. The second shows the temporal evolution of the Gulf Stream. The high resolution gravimetric geoid of Rapp is used to obtain the absolute ocean topography. Simulated drifters are used to visualize the flow pattern of the current. Meanders and rings of the current are the main features. The third is an animation of the global ocean topography on a spherical earth. The JGM-2 geoid is used to obtain the ocean topography...

  15. Retrodicting the Cenozoic evolution of the mantle: Implications for dynamic surface topography

    NASA Astrophysics Data System (ADS)

    Glišović, Petar; Forte, Alessandro; Rowley, David; Simmons, Nathan; Grand, Stephen

    2014-05-01

    Seismic tomography is the essential starting ingredient for constructing realistic models of the mantle convective flow and for successfully predicting a wide range of convection-related surface observables. However, the lack of knowledge of the initial thermal state of the mantle in the geological past is still an outstanding problem in mantle convection. The resolution of this problem requires models of 3-D mantle evolution that yield maximum consistency with a wide suite of geophysical constraints. Quantifying the robustness of the reconstructed thermal evolution is another major concern. We have carried out mantle dynamic simulations (Glišović & Forte, EPSL 2014) using a pseudo-spectral solution for compressible-flow thermal convection in 3-D spectral geometry that directly incorporate: 1) joint seismic-geodynamic inversions of mantle density structure with constraints provided by mineral physics data (Simmons et al., GJI 2009); and 2) constraints on mantle viscosity inferred by inversion of a suite of convection-related and glacial isostatic adjustment data sets (Mitrovica & Forte, EPSL 2004) characterised by Earth-like Rayleigh numbers. These time-reversed convection simulations reveal how the buoyancy associated with hot, active upwellings is a major driver of the mantle-wide convective circulation and the changes in dynamic topography at the Earth's surface. These simulations reveal, for example, a stable and long-lived superplume under the East Pacific Rise (centred under the Easter and Pitcairn hotspots) that was previously identified by Rowley et al. (AGU 2011, Nature in review) on the basis of plate kinematic data. We also present 65 Myr reconstructions of the Reunion plume that gave rise to the Deccan Traps.

  16. The Interplay Between Conformation and Absolute Configuration in Chiral Electron Dynamics of Small Diols.

    PubMed

    Daly, Steven; Tia, Maurice; Garcia, Gustavo A; Nahon, Laurent; Powis, Ivan

    2016-09-01

    A competition between chiral characteristics alternatively attributable to either conformation or to absolute configuration is identified. Circular dichroism associated with photoexcitation of the outer orbital of configurational enantiomers of 1,3- and 2,3-butanediols has been examined with a focus on the large changes in electron chiral asymmetry produced by different molecular conformations. Experimental gas-phase measurements offer support for the theoretical modeling of this chiroptical effect. A surprising prediction is that a conformationally produced pseudo-enantiomerism in 1,3-butanediol generates a chiral response in the frontier electron dynamics that outweighs the influence of the permanent configurational handedness established at the asymmetrically substituted carbon. Induced conformation, and specifically induced conformational chirality, may thus be a dominating factor in chiral molecular recognition in such systems. PMID:27445202

  17. Recognising the Different Roles and Expressions of Dynamic Mantle Flow and Plate Kinematics in the Evolution of Africa's Topography

    NASA Astrophysics Data System (ADS)

    Brown, R. W.; Wildman, M.; Beucher, R.; Chardon, D.; Rouby, D.; Stuart, F. M.; Persano, C.

    2014-12-01

    Continental elevation can be partitioned into contributions from intrinsic isostatic buoyancy forces arising from thermal, compositional and thickness variations within the crust or lithosphere and external geodynamic forces. External forces include horizontal in-plane stress and vertical forces arising from convection within the deep mantle giving rise to dynamic uplift of Earth's surface. In essence both of these are ultimately expressions of the energy driving and/or contained within the convecting lithosphere-mantle system, and so are not really separate, but their expression in the topography at the surface is often quite different. The term dynamic uplift refers to topography that is supported by the vertical stresses arising from the upward viscous flow of mantle impinging on the base of the lithosphere, and it is typically regional in extent. In recent years the importance of dynamic uplift as a major control on continental topography has been emphasised by the advances in seismology and progress in understanding the structure of the shallow as well as deep mantle. However, the difficulty of quantifying surface uplift within non-orogenic regions has hampered progress in understanding how continental topography reacts to the competing interaction between mantle process creating the topography and surface processes that destroy it. Any geomorphic response, and the resulting erosion or sedimentary signal related to these uplift events, is strongly filtered through the response times of surface processes that are responding to relatively small changes in surface gradient. But with care, the erosional history, measured over large areas, can monitor the evolution of continental scale topography and this can be very effectively measured at appropriate temporal and spatial scales using low temperature thermochronometry. This approach, combined with analysis of the offshore sedimentary record around southern Africa, has proved to be very effective at documenting the

  18. Reconcile Mantle Dynamic Models with Compositionally Distinct and Stable LLSVPs with the Observations of the Geoid and Dynamic Topography

    NASA Astrophysics Data System (ADS)

    Liu, X.; Zhong, S.

    2015-12-01

    The geoid has been well explained in mantle flow models with the buoyancy inferred from seismic models that in turn place constraints on mantle viscosity structure (e.g., Hager & Richards, 1989). These models often assume a whole-mantle convection with uniform composition and 1-D viscosity. However, seismic and geochemical observations suggest possible existence of chemically distinct piles under Africa and Pacific which extends hundreds of kilometers above the CMB (i.e., LLSVPs). As compositional heterogeneity would significantly alter the interpretation of seismic anomalies as buoyancy structure, important questions are whether a thermochemical mantle model based on seismic velocity anomalies can reconcile the geoid and how this may impact inference of mantle viscosity structure. In this study, we formulate mantle flow models that use buoyancy derived from seismic model S40RTS (Ritsema et al., 2011), assuming that the LLSVPs are stable with negative buoyancy. The models use temperature-, depth- and composition-dependent viscosity and are computed for the geoid, dynamic topography and flow velocity using CitcomS. Seismic anomalies are converted to buoyancy using thermal conversion factor cT for the whole mantle materials and composition conversion factor cc for the chemical piles defined as the domains with seismic slow anomaly <-0.5% and a maximum height of 500 km. The temperature-dependence viscosity gives rise to 3 orders of magnitude variations in viscosity, and horizontally averaged viscosity profile is consistent with the inferred 1-D viscosity from the geoid. The viscosity in the chemical piles is further reduced by a factor of Cvisc to represent the compositional effect. We measure the stability of the chemical piles by the RMS vertical velocities on the piles boundary. Our preferred thermochemical models with stable chemical piles reach similar variance reduction of geoid at ~64% to that for the uniform composition models. In the preferred model, cT is ~0

  19. Absolute Binding Free Energy Calculations Using Molecular Dynamics Simulations with Restraining Potentials

    PubMed Central

    Wang, Jiyao; Deng, Yuqing; Roux, Benoît

    2006-01-01

    The absolute (standard) binding free energy of eight FK506-related ligands to FKBP12 is calculated using free energy perturbation molecular dynamics (FEP/MD) simulations with explicit solvent. A number of features are implemented to improve the accuracy and enhance the convergence of the calculations. First, the absolute binding free energy is decomposed into sequential steps during which the ligand-surrounding interactions as well as various biasing potentials restraining the translation, orientation, and conformation of the ligand are turned “on” and “off.” Second, sampling of the ligand conformation is enforced by a restraining potential based on the root mean-square deviation relative to the bound state conformation. The effect of all the restraining potentials is rigorously unbiased, and it is shown explicitly that the final results are independent of all artificial restraints. Third, the repulsive and dispersive free energy contribution arising from the Lennard-Jones interactions of the ligand with its surrounding (protein and solvent) is calculated using the Weeks-Chandler-Andersen separation. This separation also improves convergence of the FEP/MD calculations. Fourth, to decrease the computational cost, only a small number of atoms in the vicinity of the binding site are simulated explicitly, while all the influence of the remaining atoms is incorporated implicitly using the generalized solvent boundary potential (GSBP) method. With GSBP, the size of the simulated FKBP12/ligand systems is significantly reduced, from ∼25,000 to 2500. The computations are very efficient and the statistical error is small (∼1 kcal/mol). The calculated binding free energies are generally in good agreement with available experimental data and previous calculations (within ∼2 kcal/mol). The present results indicate that a strategy based on FEP/MD simulations of a reduced GSBP atomic model sampled with conformational, translational, and orientational restraining

  20. Implications for anomalous mantle pressure and dynamic topography from lithospheric stress patterns in the North Atlantic Realm

    NASA Astrophysics Data System (ADS)

    Schiffer, Christian; Nielsen, Søren Bom

    2016-08-01

    With convergent plate boundaries at some distance, the sources of the lithospheric stress field of the North Atlantic Realm are mainly mantle tractions at the base of the lithosphere, lithospheric density structure and topography. Given this, we estimate horizontal deviatoric stresses using a well-established thin sheet model in a global finite element representation. We adjust the lithospheric thickness and the sub-lithospheric pressure iteratively, comparing modelled in plane stress with the observations of the World Stress Map. We find that an anomalous mantle pressure associated with the Iceland and Azores melt anomalies, as well as topography are able to explain the general pattern of the principle horizontal stress directions. The Iceland melt anomaly overprints the classic ridge push perpendicular to the Mid Atlantic ridge and affects the conjugate passive margins in East Greenland more than in western Scandinavia. The dynamic support of topography shows a distinct maximum of c. 1000 m in Iceland and amounts <150 m along the coast of south-western Norway and 250-350 m along the coast of East Greenland. Considering that large areas of the North Atlantic Realm have been estimated to be sub-aerial during the time of break-up, two components of dynamic topography seem to have affected the area: a short-lived, which affected a wider area along the rift system and quickly dissipated after break-up, and a more durable in the close vicinity of Iceland. This is consistent with the appearance of a buoyancy anomaly at the base of the North Atlantic lithosphere at or slightly before continental breakup, relatively fast dissipation of the fringes of this, and continued melt generation below Iceland.

  1. Prediction of Seasonal to Inter-annual Hydro-climatology including the Effects of Vegetation Dynamics and Topography over Large River Basins

    NASA Astrophysics Data System (ADS)

    Bisht, G.; Narayan, U.; Bras, R. L.

    2008-12-01

    The goal of the proposed research is to enhance the predictability of hydrology and atmospheric conditions at daily, seasonal and inter-annual time scales. Capturing the interplay between seasonally dynamic vegetation and topography occurring through the local mechanisms of radiation and soil moisture re- distribution may contribute significantly towards increasing hydro-climatological predictability at fine spatio- temporal scales. We present a coupled model that improves the representation of vegetation dynamics with complex topography using the TIN (Triangulated Irregular Network)-based Real-time Integrated Basin Simulator (tRIBS) coupled with an advanced regional atmospheric model (WRF, Weather Research Forecasting). The tRIBS-WRF coupled model has been implemented in a parallel computing framework to allow fine scale simulations over large spatial domains for multi year time periods. The simulations have been carried out for a multi year period and we analyze the accuracy of predicted hydro-climatological variables such as monthly precipitation accumulation, soil moisture and vegetation (LAI, phenology) for different cases of (i) flat topography, prescribed vegetation (ii) real topography, prescribed vegetation (iii) flat topography, dynamic vegetation and (iv) real topography, dynamic vegetation. The simulations have been performed in a semi arid region in the South Western United States with the domain centered on a well-instrumented test basin - the Walnut Gulch Experimental Watershed. Energy balance as well as soil moisture measurements from the test basin are used to evaluate the simulations. We also use MODIS NDVI observations to evaluate the simulated vegetation spatio-temporal dynamics.

  2. Easy Absolute Values? Absolutely

    ERIC Educational Resources Information Center

    Taylor, Sharon E.; Mittag, Kathleen Cage

    2015-01-01

    The authors teach a problem-solving course for preservice middle-grades education majors that includes concepts dealing with absolute-value computations, equations, and inequalities. Many of these students like mathematics and plan to teach it, so they are adept at symbolic manipulations. Getting them to think differently about a concept that they…

  3. Dynamic localization and negative absolute conductance in terahertz driven semiconductor superlattices

    SciTech Connect

    Keay, B.J.; Allen, S.J.; Campman, K.L.

    1995-12-31

    We report the first observation of Negative Absolute Conductance (NAC), dynamic localization and multiphoton stimulated emission assisted tunneling in terahertz driven semiconductor superlattices. Theories predicting NAC in semiconductor superlattices subjected to AC electric fields have existed for twenty years, but have never been verified experimentally. Most theories are based upon semiclassical arguments and are only valid for superlattices in the miniband or coherent tunneling regime. We are not aware of models predicting NAC in superlattices in the sequential tunneling regime, although there has been recent theoretical work on double-barrier structures. Perhaps the most remarkable result is found in the power dependence of the current-voltage (I-V) characteristics near zero DC bias. As the laser power is increased the current decreases towards zero and then becomes negative. This result implies that the electrons are absorbing energy from the laser field, producing a net current in the direction opposite to the applied voltage. NAC around zero DC bias is a particularly surprising observation considering photon-assisted tunneling is not expected to be observable between the ground states of neighboring quantum wells in a semiconductor superlattice. Contrary to this believe our results are most readily attributable to photon absorption and multiphoton emission between ground states of neighboring wells. The I-V characteristics measured in the presence of terahertz radiation at low DC bias also contain steps and plateaus analogous to photon-assisted steps observed in superconducting junctions. As many as three steps have been clearly resolved corresponding to stimulated emission into the terahertz field by a three-photon process.

  4. Absolute dosimetry on a dynamically scanned sample for synchrotron radiotherapy using graphite calorimetry and ionization chambers

    NASA Astrophysics Data System (ADS)

    Lye, J. E.; Harty, P. D.; Butler, D. J.; Crosbie, J. C.; Livingstone, J.; Poole, C. M.; Ramanathan, G.; Wright, T.; Stevenson, A. W.

    2016-06-01

    The absolute dose delivered to a dynamically scanned sample in the Imaging and Medical Beamline (IMBL) on the Australian Synchrotron was measured with a graphite calorimeter anticipated to be established as a primary standard for synchrotron dosimetry. The calorimetry was compared to measurements using a free-air chamber (FAC), a PTW 31 014 Pinpoint ionization chamber, and a PTW 34 001 Roos ionization chamber. The IMBL beam height is limited to approximately 2 mm. To produce clinically useful beams of a few centimetres the beam must be scanned in the vertical direction. In practice it is the patient/detector that is scanned and the scanning velocity defines the dose that is delivered. The calorimeter, FAC, and Roos chamber measure the dose area product which is then converted to central axis dose with the scanned beam area derived from Monte Carlo (MC) simulations and film measurements. The Pinpoint chamber measures the central axis dose directly and does not require beam area measurements. The calorimeter and FAC measure dose from first principles. The calorimetry requires conversion of the measured absorbed dose to graphite to absorbed dose to water using MC calculations with the EGSnrc code. Air kerma measurements from the free air chamber were converted to absorbed dose to water using the AAPM TG-61 protocol. The two ionization chambers are secondary standards requiring calibration with kilovoltage x-ray tubes. The Roos and Pinpoint chambers were calibrated against the Australian primary standard for air kerma at the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA). Agreement of order 2% or better was obtained between the calorimetry and ionization chambers. The FAC measured a dose 3–5% higher than the calorimetry, within the stated uncertainties.

  5. Absolute dosimetry on a dynamically scanned sample for synchrotron radiotherapy using graphite calorimetry and ionization chambers.

    PubMed

    Lye, J E; Harty, P D; Butler, D J; Crosbie, J C; Livingstone, J; Poole, C M; Ramanathan, G; Wright, T; Stevenson, A W

    2016-06-01

    The absolute dose delivered to a dynamically scanned sample in the Imaging and Medical Beamline (IMBL) on the Australian Synchrotron was measured with a graphite calorimeter anticipated to be established as a primary standard for synchrotron dosimetry. The calorimetry was compared to measurements using a free-air chamber (FAC), a PTW 31 014 Pinpoint ionization chamber, and a PTW 34 001 Roos ionization chamber. The IMBL beam height is limited to approximately 2 mm. To produce clinically useful beams of a few centimetres the beam must be scanned in the vertical direction. In practice it is the patient/detector that is scanned and the scanning velocity defines the dose that is delivered. The calorimeter, FAC, and Roos chamber measure the dose area product which is then converted to central axis dose with the scanned beam area derived from Monte Carlo (MC) simulations and film measurements. The Pinpoint chamber measures the central axis dose directly and does not require beam area measurements. The calorimeter and FAC measure dose from first principles. The calorimetry requires conversion of the measured absorbed dose to graphite to absorbed dose to water using MC calculations with the EGSnrc code. Air kerma measurements from the free air chamber were converted to absorbed dose to water using the AAPM TG-61 protocol. The two ionization chambers are secondary standards requiring calibration with kilovoltage x-ray tubes. The Roos and Pinpoint chambers were calibrated against the Australian primary standard for air kerma at the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA). Agreement of order 2% or better was obtained between the calorimetry and ionization chambers. The FAC measured a dose 3-5% higher than the calorimetry, within the stated uncertainties. PMID:27192396

  6. A quantitative assessment of the depth sensitivity of an optical topography system using a solid dynamic tissue-phantom.

    PubMed

    Correia, Teresa; Banga, Anil; Everdell, N L; Gibson, Adam P; Hebden, Jeremy C

    2009-10-21

    A solid dynamic phantom with tissue-like optical properties is presented, which contains seven discrete targets impregnated with thermochromic pigment located at different depths from the surface. Changes in absorption are obtained in response to localized heating of the targets, simulating haemodynamic changes occurring in the brain and other tissues. The depth sensitivity of a continuous wave optical topography system was assessed successfully using the phantom. Images of the targets have been reconstructed using a spatially variant regularization, and the determined spatial localization in the depth direction is shown to be accurate within an uncertainty of about 3 mm down to a depth of about 30 mm. PMID:19794240

  7. A quantitative assessment of the depth sensitivity of an optical topography system using a solid dynamic tissue-phantom

    NASA Astrophysics Data System (ADS)

    Correia, Teresa; Banga, Anil; Everdell, N. L.; Gibson, Adam P.; Hebden, Jeremy C.

    2009-10-01

    A solid dynamic phantom with tissue-like optical properties is presented, which contains seven discrete targets impregnated with thermochromic pigment located at different depths from the surface. Changes in absorption are obtained in response to localized heating of the targets, simulating haemodynamic changes occurring in the brain and other tissues. The depth sensitivity of a continuous wave optical topography system was assessed successfully using the phantom. Images of the targets have been reconstructed using a spatially variant regularization, and the determined spatial localization in the depth direction is shown to be accurate within an uncertainty of about 3 mm down to a depth of about 30 mm.

  8. The Development of a Degree 360 Expansion of the Dynamic Ocean Topography of the POCM_4B Global Circulation Model

    NASA Technical Reports Server (NTRS)

    Rapp, Richard H.

    1998-01-01

    This paper documents the development of a degree 360 expansion of the dynamic ocean topography (DOT) of the POCM_4B ocean circulation model. The principles and software used that led to the final model are described. A key principle was the development of interpolated DOT values into land areas to avoid discontinuities at or near the land/ocean interface. The power spectrum of the POCM_4B is also presented with comparisons made between orthonormal (ON) and spherical harmonic magnitudes to degree 24. A merged file of ON and SH computed degree variances is proposed for applications where the DOT power spectrum from low to high (360) degrees is needed.

  9. Physical Parameters Controlling Subduction Dynamics and Surface Topography in Self-consistent Global Models of Mantle Convection

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

    Recent advances in numerical modelling allow global models of mantle convection to realistically reproduce the behaviour at convergent plate boundaries (Crameri et al., 2012a). This allows for a more extensive study of subduction that, in contrast to the numerous regional models, incorporates the complete framework of mantle convection. Here, we focus on different aspects of mantle convection including (i) slab dip variations, (ii) variations in radial mantle viscosity, and (iii) the presence of localised mantle upwellings and discuss their control on the dynamics of Earth-like plate tectonics. Additionally, we present the effect these parameter variations have on measurable quantities like dynamic topography and plate velocity. The models are calculated by the finite-volume code Stag-YY (e.g., Tackley 2008) using a multi-grid method on a fully staggered grid. Second, the sticky-air method (Matsumoto and Tomoda 1983; Schmeling et al, 2008) is applied and thus approximates a free surface when the sticky-air parameters are chosen carefully (Crameri et al., 2012b). Overall, this study demonstrates the ability of various parameters to significantly influence both subduction dynamics and surface topography. REFERENCES Crameri, F., et al. (2012a), Geophys. Res. Lett., 39(3). Crameri, F., et al. (2012b), Geophys. J. Int., 189(1). Matsumoto, T., and Y. Tomoda (1983), J. Phys. Earth, 31(3). Schmeling, H., et al. (2008), Phys. Earth Planet. Int., 171(1-4). Tackley, P. J. (2008), Phys. Earth Planet. Int., 171(1-4).

  10. Structure and Dynamics of the Polar Regions of Mars from MGS Topography and Gravity

    NASA Technical Reports Server (NTRS)

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

    2000-01-01

    The Mars Global Surveyor (MGS) spacecraft has been engaged in systematic mapping of Mars since insertion into Mars orbit in September, 1997. The objectives of the MGS mission are to globally map Mars as well as to quantify seasonal changes on the planet. MGS geophysical/geodetic observations of topography from the Mars Orbiter Laser Altimeter (MOLA) and gravity from the Radio Science investigation are providing significant new insights on both static and time-varying aspects of the polar regions of Mars. These observations have implications for polar processes on diurnal seasonal and climatic timescales. Thus far, MOLA has collected over 300 million precise measurements of Martian topography and cloud heights. The instrument has also provided measurements of the width of the backscattered optical pulse and of the 1064 nm reflectivity of the Martian surface and atmosphere. The along-track resolution of MOLA ground shots is approx. 300 m and the across-track spacing in the polar regions is a maximum of about four kilometers. The vertical accuracy of the topography is determined by the precision recovery of spacecraft orbits from the Radio Science investigation, which includes MOLA altimetry in the form of crossovers. This accuracy is currently approx. one meter. The gravity field is derived from X-band Doppler tracking with typical accuracy of 0.03 to 0.05 mm/s averaged over ten seconds. Current Mars gravity fields are to approximately degree and order 80 but are interpretable to the approximate degree and order 60 (spatial resolution < 180 km), which represents an estimate of the approximate coefficient limit of a field that can be produced without a power law constraint on the gravitational field inversion, which is commonly imposed for solution stability. Additional information is contained in the original extended abstract.

  11. The correction of vibration in frequency scanning interferometry based absolute distance measurement system for dynamic measurements

    NASA Astrophysics Data System (ADS)

    Lu, Cheng; Liu, Guodong; Liu, Bingguo; Chen, Fengdong; Zhuang, Zhitao; Xu, Xinke; Gan, Yu

    2015-10-01

    Absolute distance measurement systems are of significant interest in the field of metrology, which could improve the manufacturing efficiency and accuracy of large assemblies in fields such as aircraft construction, automotive engineering, and the production of modern windmill blades. Frequency scanning interferometry demonstrates noticeable advantages as an absolute distance measurement system which has a high precision and doesn't depend on a cooperative target. In this paper , the influence of inevitable vibration in the frequency scanning interferometry based absolute distance measurement system is analyzed. The distance spectrum is broadened as the existence of Doppler effect caused by vibration, which will bring in a measurement error more than 103 times bigger than the changes of optical path difference. In order to decrease the influence of vibration, the changes of the optical path difference are monitored by a frequency stabilized laser, which runs parallel to the frequency scanning interferometry. The experiment has verified the effectiveness of this method.

  12. (Photo-)thermally induced formation of dynamic surface topographies in polymer hydrogel networks.

    PubMed

    Liu, Danqing; Bastiaansen, Cees W M; den Toonder, Jaap M J; Broer, Dirk J

    2013-05-01

    In this Article, we report on our approaches to creating responsive hydrogel coatings with surfaces that can be switched between a close to flat state and a state with a predesigned topographic pattern. The trigger is either temperature or, indirectly, light. The hydrogel coatings are based on the known thermal responsive poly(N-isopropylacrylamide) utilizing its solubility change at its lower critical solution temperature (LCST) at around 32 °C. Using this material in combination with controlled cross-linking, we developed three fabrication strategies. Thermally switching symmetric surface topographies were created by careful and spatial control of the cross-link density. Sensitivity to light was created by patterns of tin oxide converting absorbed light into local heat. And to broaden the application range, we introduced a method based on volumetric effects created by a corrugated substrate. The latter method allows for the formation of asymmetric or slanted surface structures. PMID:23573907

  13. The ups and downs of North America: Evaluating the role of mantle dynamic topography since the Mesozoic

    NASA Astrophysics Data System (ADS)

    Liu, Lijun

    2015-09-01

    The driving force for transient vertical motions of Earth's surface remains an outstanding question. A main difficulty lies in the uncertain role of the underlying mantle, especially during the geological past. Here I review previous studies on both observational constraints and physical mechanisms of North American topographic evolution since the Mesozoic. I first summarize the North American vertical motion history using proxies from structural geology, geochronology, sedimentary stratigraphy, and geomorphology, based on which I then discuss the published physical models. Overall, there is a progressive consensus on the contribution of mantle dynamic topography due to buoyancy structures associated with the past subduction. At the continental scale, a largely west-to-east migrating deformation pattern suggests an eastward translation of mantle dynamic effects, consistent with models involving an eastward subduction and sinking of former Farallon slabs since the Cretaceous. Among the existing models, the inverse model based on an adjoint algorithm and time-dependent data constraints provides the most extensive explanations for the temporal changes of North American topography since the Mesozoic. At regional scales, debates still exist on the predicted surface subsidence and uplift within both the western and eastern United States, where discrepancies are likely due to differences in model setup (e.g., mantle dynamic properties and boundary conditions) and the amount of time-dependent observational constraints. Toward the development of the next-generation predictive geodynamic models, new research directions may include (1) development of enhanced data assimilation capabilities, (2) exploration of multiscale and multiphysics processes, and (3) cross-disciplinary code coupling.

  14. Sediment Transport, Complex Topography, and Hydrokinetic Turbines: Bedform Dynamics, Local Scour, and the Effect on Turbine Performance.

    NASA Astrophysics Data System (ADS)

    Guala, M.; Hill, C.; Kozarek, J. L.; Sotiropoulos, F.

    2015-12-01

    Multi-scale experiments on the interactions between axial-flow marine hydrokinetic (MHK) turbines, sediment transport and complex channel topography were performed at St. Anthony Falls Laboratory (SAFL), University of Minnesota. Model axial-flow three-bladed turbines (rotor diameters, dT = 0.15m and 0.5m) were installed in open channel flumes with both erodible and non-erodible substrates. In erodible channels, device-induced local scour was monitored over several hydraulic conditions (clear water vs. live bedload transport) and material sizes. Synchronous velocity, bed elevation and turbine performance measurements provide an indication into the effect channel topography has on device performance. A novel data acquisition imaging system provided methods for monitoring the dynamics of bedform transport as they approached and migrated past an operating axial-flow turbine. Experiments were also performed in a realistic meandering outdoor research channel with active sediment transport to investigate MHK turbine interactions with bedform migration and turbulent flow in asymmetric channels, providing new insight into turbine-sediment interactions and turbine wake behavior in curving channels. Results provide the foundation for investigating advanced turbine control strategies for optimal power production in non-stationary environments, while also providing robust data for computational model validation enabling further investigations into the interactions between energy conversion devices and the physical environment.

  15. Particle visualization in high-power impulse magnetron sputtering. II. Absolute density dynamics

    SciTech Connect

    Britun, Nikolay Palmucci, Maria; Konstantinidis, Stephanos; Snyders, Rony

    2015-04-28

    Time-resolved characterization of an Ar-Ti high-power impulse magnetron sputtering discharge has been performed. The present, second, paper of the study is related to the discharge characterization in terms of the absolute density of species using resonant absorption spectroscopy. The results on the time-resolved density evolution of the neutral and singly-ionized Ti ground state atoms as well as the metastable Ti and Ar atoms during the discharge on- and off-time are presented. Among the others, the questions related to the inversion of population of the Ti energy sublevels, as well as to re-normalization of the two-dimensional density maps in terms of the absolute density of species, are stressed.

  16. Absolute Summ

    NASA Astrophysics Data System (ADS)

    Phillips, Alfred, Jr.

    Summ means the entirety of the multiverse. It seems clear, from the inflation theories of A. Guth and others, that the creation of many universes is plausible. We argue that Absolute cosmological ideas, not unlike those of I. Newton, may be consistent with dynamic multiverse creations. As suggested in W. Heisenberg's uncertainty principle, and with the Anthropic Principle defended by S. Hawking, et al., human consciousness, buttressed by findings of neuroscience, may have to be considered in our models. Predictability, as A. Einstein realized with Invariants and General Relativity, may be required for new ideas to be part of physics. We present here a two postulate model geared to an Absolute Summ. The seedbed of this work is part of Akhnaton's philosophy (see S. Freud, Moses and Monotheism). Most important, however, is that the structure of human consciousness, manifest in Kenya's Rift Valley 200,000 years ago as Homo sapiens, who were the culmination of the six million year co-creation process of Hominins and Nature in Africa, allows us to do the physics that we do. .

  17. Erosion, Weathering and Stepped Topography in the Sierra Nevada, California; Quantifying the Dynamics of Hybrid (Soil-Bedrock) Landscapes

    NASA Astrophysics Data System (ADS)

    Jessup, B. S.; Miller, S. N.; Kirchner, J. W.; Riebe, C. S.

    2010-12-01

    The dynamics of granitic landscapes are regulated, in part, by bimodal weathering, which produces granular soils and expanses of bare rock ranging from meter-scale boulders to mountain-scale domes. Conceptual models for the evolution of granitic landscapes date back to Gilbert and Penck. Yet few studies have been able to realistically predict the co-occurrence of bedrock and granular soil and its implications for mountain-scale topography -- despite marked advances in quantitative landscape evolution modeling over the last few decades. Here we use terrain analysis, together with cosmogenic-nuclide measurements of erosion and weathering, to quantitatively explore Wahrhaftig's decades-old hypothesis for the development of “stepped topography” by differential weathering of bare and soil-mantled granite. According to this hypothesis, soil-mantled granite weathers much faster than bare granite; thus random erosional exposure of bare rock leads to an alternating sequence of steep, slowly weathering bedrock “steps” and gently sloped, but rapidly weathering, soil-mantled “treads”. Such treads and steps are purported to collectively account for ~2000 m of relief in the southern Sierra Nevada, California, implying that the mechanisms behind the formation of stepped topography may also account for development of mountain-scale relief in granitic landscapes. Our preliminary analysis of granitic terrain in the Sierra Nevada range suggests that steep steps often grade into gentle treads, consistent with the stepped topography hypothesis. Our data and analysis further corroborate the hypothesis with indications that bare granitic rocks erode much more slowly than their soil-mantled counterparts. This suggests that the coupling between soil production and denudation in granitic landscapes harbors a crucial tipping point; if soils are stripped to bedrock, erosion slows and soil formation is restrained to the point that bare rock can persist and rise in relief relative

  18. Multidirectional and Topography-based Dynamic-scale Varifold Representations with Application to Matching Developing Cortical Surfaces.

    PubMed

    Rekik, Islem; Li, Gang; Lin, Weili; Shen, Dinggang

    2016-07-15

    The human cerebral cortex is marked by great complexity as well as substantial dynamic changes during early postnatal development. To obtain a fairly comprehensive picture of its age-induced and/or disorder-related cortical changes, one needs to match cortical surfaces to one another, while maximizing their anatomical alignment. Methods that geodesically shoot surfaces into one another as currents (a distribution of oriented normals) and varifolds (a distribution of non-oriented normals) provide an elegant Riemannian framework for generic surface matching and reliable statistical analysis. However, both conventional current and varifold matching methods have two key limitations. First, they only use the normals of the surface to measure its geometry and guide the warping process, which overlooks the importance of the orientations of the inherently convoluted cortical sulcal and gyral folds. Second, the 'conversion' of a surface into a current or a varifold operates at a fixed scale under which geometric surface details will be neglected, which ignores the dynamic scales of cortical foldings. To overcome these limitations and improve varifold-based cortical surface registration, we propose two different strategies. The first strategy decomposes each cortical surface into its normal and tangent varifold representations, by integrating principal curvature direction field into the varifold matching framework, thus providing rich information of the orientation of cortical folding and better characterization of the complex cortical geometry. The second strategy explores the informative cortical geometric features to perform a dynamic-scale measurement of the cortical surface that depends on the local surface topography (e.g., principal curvature), thereby we introduce the concept of a topography-based dynamic-scale varifold. We tested the proposed varifold variants for registering 12 pairs of dynamically developing cortical surfaces from 0 to 6 months of age. Both

  19. The effect of rheological approximations on the dynamics and topography in 3D subduction-collision models

    NASA Astrophysics Data System (ADS)

    Pusok, Adina E.; Kaus, Boris J. P.; Popov, Anton A.

    2016-04-01

    Most of the major mountain belts and orogenic plateaus are found within the overlying plate of active or fossil subduction and/or collision zones. Moreover, they evolve differently from one another as the result of specific combinations of surface and mantle processes. These differences arise for several reasons, such as different rheological properties, different amounts of regional isostatic compensation, and different mechanisms by which forces are applied to the convergent plates. Previous 3D geodynamic models of subduction/collision processes have used various rheological approximations, making numerical results difficult to compare, since there is no clear image on the extent of these approximations on the dynamics. Here, we employ the code LaMEM to perform high-resolution long-term 3D simulations of subduction/continental collision in an integrated lithospheric and upper-mantle scale model. We test the effect of rheological approximations on mantle and lithosphere dynamics in a geometrically simplified model setup that resembles a tectonic map of the India-Asia collision zone. We use the "sticky-air" approach to allow for the development of topography and the dynamics of subduction and collision is entirely driven by slab-pull (i.e. "free subduction"). The models exhibit a wide range of behaviours depending on the rheological law employed: from linear to temperature-dependent visco-elasto-plastic rheology that takes into account both diffusion and dislocation creep. For example, we find that slab dynamics varies drastically between end member models: in viscous approximations, slab detachment is slow following a viscous thinning, while for a non-linear visco-elasto-plastic rheology, slab detachment is relatively fast, inducing strong mantle flow in the slab window. We also examine the stress states in the subducting and overriding plates and topography evolution in the upper plate, and we discuss the implications on lithosphere dynamics at convergent margins

  20. Inferences on the Emplacement Dynamics of Martian Impact Crater Ejecta: Constraints from Mola Topography

    NASA Technical Reports Server (NTRS)

    Garvin, J. B.; Baloga, S. M.

    1998-01-01

    Lobate ejecta deposits surround many of the younger impact craters on Mars. Viking Orbiter images indicate the distal parts of the ejecta blankets of these lobate craters are characterized by ramparts. In the absence of detailed topographic data for characterizing the topology of these apparently fluidized ejecta deposits, physical models have relied upon their morphologic characteristics. The most widely accepted model for the formation of such rampart ejecta deposits on Mars invokes fluidization of the ejecta to produce one or more viscous flow lobes. The availability of high-precision topographic data from the Mars Orbiter Laser Altimeter [4,51 facilitates a more quantitative examination of the physical processes involved in the formation of rampart ejecta deposits on Mars. Here we investigate the emplacement constraints that can be developed from the dimensions, topography, and morphology of martian rampart craters. The primary assumptions we have adopted are: (1) the ejecta blanket is emplaced as a continuum flow over the martian surface, rather than an airfall deposit, and (2) that the observable dimensions of the deposits are indicative of flow dimensions during emplacement.

  1. Dynamics of large-amplitude internal waves in stratified flows over topography

    NASA Astrophysics Data System (ADS)

    Prasad, Dilip

    1997-10-01

    In the first problem, the flow of a Boussinesq density- stratified fluid of large depth past the algebraic mountain ('Witch of Agnesi') is studied in the hydrostatic limit using the asymptotic theory of Kantzios & Akylas. The upstream conditions are those of constant velocity and Brunt-Vaisala frequency. On the further assumptions that the flow is steady and there is no permanent alteration of the upstream flow conditions (no upstream influence), Long's model predicts a critical amplitude of the mountain (/epsilon=0.85) above which local density inversions occur, leading to convective overturning. Linear stability analysis demonstrates that Long's steady flow is in fact unstable to infinitesimal modulations at topography amplitudes below this critical value, 0.65/ ~

  2. Future Antarctic Bed Topography and Its Implications for Ice Sheet Dynamics

    NASA Technical Reports Server (NTRS)

    Adhikari, Surendra; Ivins, Erik R.; Larour, Eric Y.; Seroussi, Helene L.; Morlighem, Mathieu; Nowicki, S.

    2014-01-01

    The Antarctic bedrock is evolving as the solid Earth responds to the past and ongoing evolution of the ice sheet. A recently improved ice loading history suggests that the Antarctic Ice Sheet (AIS) has generally been losing its mass since the Last Glacial Maximum. In a sustained warming climate, the AIS is predicted to retreat at a greater pace, primarily via melting beneath the ice shelves.We employ the glacial isostatic adjustment (GIA) capability of the Ice Sheet System Model (ISSM) to combine these past and future ice loadings and provide the new solid Earth computations for the AIS.We find that past loading is relatively less important than future loading for the evolution of the future bed topography. Our computations predict that the West Antarctic Ice Sheet (WAIS) may uplift by a few meters and a few tens of meters at years AD 2100 and 2500, respectively, and that the East Antarctic Ice Sheet is likely to remain unchanged or subside minimally except around the Amery Ice Shelf. The Amundsen Sea Sector in particular is predicted to rise at the greatest rate; one hundred years of ice evolution in this region, for example, predicts that the coastline of Pine Island Bay will approach roughly 45mmyr-1 in viscoelastic vertical motion. Of particular importance, we systematically demonstrate that the effect of a pervasive and large GIA uplift in the WAIS is generally associated with the flattening of reverse bed slope, reduction of local sea depth, and thus the extension of grounding line (GL) towards the continental shelf. Using the 3-D higher-order ice flow capability of ISSM, such a migration of GL is shown to inhibit the ice flow. This negative feedback between the ice sheet and the solid Earth may promote stability in marine portions of the ice sheet in the future.

  3. Geological Influences on Bedrock Topography and East Antarctic Ice Sheet Dynamics in the Wilkes Subglacial Basin

    NASA Astrophysics Data System (ADS)

    Ferraccioli, F.; Armadillo, E.; Young, D. A.; Blankenship, D. D.; Jordan, T. A.; Balbi, P.; Bozzo, E.; Siegert, M. J.

    2014-12-01

    The Wilkes Subglacial Basin (WSB) extends for 1,400 km from George V Land into the interior of East Antarctica and hosts several major glaciers that drain a large sector of the East Antarctic Ice Sheet (EAIS). This region is of key significance for the long-term stability of the ice sheet in East Antarctica, as it lies well below sea level and its bedrock deepens inland, making it potentially prone to marine ice sheet instability, much like areas of the West Antarctic Ice Sheet (WAIS) that are presently experiencing significant mass loss. We present new enhanced potential field images of the WSB combined with existing radar imaging to study geological controls on bedrock topography and ice flow regimes in this key sector of the ice sheet. These images reveal mayor Precambrian and Paleozoic basement faults that exert tectonic controls both on the margins of the basin and its sub-basins. Several major sub-basins can be recognised: the Eastern Basin, the Central Basins and the Western Basins. Using ICECAP aerogeophysical data we show that these tectonically controlled interior basins connect to newly identified basins underlying the Cook Ice Shelf region. This connection implies that any ocean-induced changes at the margin of the EAIS could potentially propagate rapidly further into the interior. With the aid of simple magnetic and gravity models we show that the WSB does not presently include major post Jurassic sedimentary infill. Its bedrock geology is highly variable and includes Proterozoic basement, Neoproterozoic and Cambrian sediments, intruded by Cambrian arc rocks, and cover rocks formed by Beacon sediments intruded by Jurassic Ferrar sills. Enhanced ice flow in this part of the EAIS occurs therefore in a area of mixed and spatially variable bedrock geology. This contrasts with some regions of the WAIS where more extensive sedimentary basins may represent a geological template for the onset and maintenance of fast glacial flow.

  4. Dynamics of plasma formation, relaxation, and topography modification induced by femtosecond laser pulses in crystalline and amorphous dielectrics

    SciTech Connect

    Puerto, D.; Siegel, J.; Gawelda, W.; Galvan-Sosa, M.; Solis, J.; Ehrentraut, L.; Bonse, J.

    2010-05-15

    We have studied plasma formation and relaxation dynamics along with the corresponding topography modifications in fused silica and sapphire induced by single femtosecond laser pulses (800 nm and 120 fs). These materials, representative of high bandgap amorphous and crystalline dielectrics, respectively, require nonlinear mechanisms to absorb the laser light. The study employed a femtosecond time-resolved microscopy technique that allows obtaining reflectivity and transmission images of the material surface at well-defined temporal delays after the arrival of the pump pulse which excites the dielectric material. The transient evolution of the free-electron plasma formed can be followed by combining the time-resolved optical data with a Drude model to estimate transient electron densities and skin depths. The temporal evolution of the optical properties is very similar in both materials within the first few hundred picoseconds, including the formation of a high reflectivity ring at about 7 ps. In contrast, at longer delays (100 ps-20 ns) the behavior of both materials differs significantly, revealing a longer lasting ablation process in sapphire. Moreover, transient images of sapphire show a concentric ring pattern surrounding the ablation crater, which is not observed in fused silica. We attribute this phenomenon to optical diffraction at a transient elevation of the ejected molten material at the crater border. On the other hand, the final topography of the ablation crater is radically different for each material. While in fused silica a relatively smooth crater with two distinct regimes is observed, sapphire shows much steeper crater walls, surrounded by a weak depression along with cracks in the material surface. These differences are explained in terms of the most relevant thermal and mechanical properties of the material. Despite these differences the maximum crater depth is comparable in both material at the highest fluences used (16 J/cm{sup 2}). The

  5. Sea level change since the Pliocene - a new formalism for predicting sea level in the presence of dynamic topography and isostasy

    NASA Astrophysics Data System (ADS)

    Austermann, Jacqueline; Rovere, Alessio; Moucha, Robert; Mitrovica, Jerry X.; Rowley, David B.; Forte, Alessandro M.; Raymo, Maureen E.

    2014-05-01

    Dynamic topography (DT), as reflected in local sea level change, provides a unique lens for studying the imprint of deep Earth dynamics on the Earth's surface. The elevation of paleo-shorelines over long time scales is, however, not only perturbed by DT but also by glacial isostatic adjustment (GIA) and eustatic changes in sea level. Isolating these contributions is essential for efforts to constrain past changes in ice volume or mantle convection models. Previous studies have performed this separation by modeling dynamic topography and superimposing the signal on the elevation of a GIA-corrected paleo-shoreline. However, this approach neglects deformation of the Earth in response to changes in the ocean load and geometry driven by DT. We describe a generalized, gravitationally self-consistent framework for computing sea-level changes that incorporates DT and GIA. The formalism is based on a sea-level theory developed within the GIA community that takes accurate account of viscoelastic deformation of the solid Earth, perturbations in the gravity field, migration of shorelines and the feedback into sea-level of contemporaneous (load-induced) changes in Earth rotation. Specifically, dynamic topography is introduced as a perturbation to the elevation of the solid surface that does not load the Earth because it is dynamically supported. However, water that is displaced by DT is allowed to redistribute, perturb the gravitational field and load (or unload) the ocean floor wherever the water column is increased (or decreased). The problem is complicated by plate tectonics, which (in a tectonic reference frame) leaves changes in topography and DT undefined in areas of the ocean floor where plates have been subducted. We interpolate these regions by imposing mass conservation of both the solid Earth and water on the reconstructed topography. We use the new formalism to calculate sea level change since the mid-Pliocene (3 Ma) using recent global simulations of dynamic

  6. Inherently mass-conservative version of the semi-Lagrangian Absolute Vorticity (SL-AV) atmospheric model dynamical core

    NASA Astrophysics Data System (ADS)

    Shashkin, V. V.; Tolstykh, M. A.

    2013-09-01

    The semi-Lagrangian Absolute Vorticity (SL-AV) atmospheric model is the global semi-Lagrangian hydrostatic model used for operational medium-range and seasonal forecasts at Hydrometeorological centre of Russia. The distinct feature of SL-AV dynamical core is the semi-implicit semi-Lagrangian vorticity-divergence formulation on the unstaggered grid. Semi-implicit semi-Lagrangian approach allows for long time steps while violates the global and local mass-conservation. In particular, the total mass in simulations with semi-Lagrangian models can drift significantly if no aposteriori mass-fixing algorithms are applied. However, the global mass-fixing algorithms degrade the local mass conservation. The inherently mass-conservative version of SL-AV model dynamical core presented in the article ensures global and local mass conservation without mass-fixing algorithms. The mass conservation is achieved with the introduction of the finite-volume semi-Lagrangian discretization for continuity equation based on the 3-D extension of the conservative cascade semi-Lagrangian transport scheme (CCS). The numerical experiments show that the presented new version of SL-AV dynamical core combines the accuracy and stability of the standard SL-AV dynamical core with the mass-conservation properties. The results of the mountain induced Rossby wave test and baroclinic instability test for mass-conservative dynamical core are found to be in agreement with the results available in literature.

  7. Inherently mass-conservative version of the semi-Lagrangian absolute vorticity (SL-AV) atmospheric model dynamical core

    NASA Astrophysics Data System (ADS)

    Shashkin, V. V.; Tolstykh, M. A.

    2014-02-01

    The semi-Lagrangian absolute vorticity (SL-AV) atmospheric model is the global semi-Lagrangian hydrostatic model used for operational medium-range and seasonal forecasts at the Hydrometeorological Centre of Russia. The distinct feature of the SL-AV dynamical core is the semi-implicit, semi-Lagrangian vorticity-divergence formulation on the unstaggered grid. A semi-implicit, semi-Lagrangian approach allows for long time steps but violates the global and local mass conservation. In particular, the total mass in simulations with semi-Lagrangian models can drift significantly if no a posteriori mass-fixing algorithm is applied. However, the global mass-fixing algorithms degrade the local mass conservation. The new inherently mass-conservative version of the SL-AV model dynamical core presented here ensures global and local mass conservation without mass-fixing algorithms. The mass conservation is achieved with the introduction of the finite-volume, semi-Lagrangian discretization for a continuity equation based on the 3-D extension of the conservative cascade semi-Lagrangian transport scheme (CCS). Numerical experiments show that the new version of the SL-AV dynamical core presented combines the accuracy and stability of the standard SL-AV dynamical core with the mass-conservation properties. The results of the mountain-induced Rossby-wave test and baroclinic instability test for the mass-conservative dynamical core are found to be in agreement with the results available in the literature.

  8. Sub-micron lateral topography affects endothelial migration by modulation of focal adhesion dynamics.

    PubMed

    Antonini, S; Meucci, S; Jacchetti, E; Klingauf, M; Beltram, F; Poulikakos, D; Cecchini, M; Ferrari, A

    2015-06-01

    Through the interaction with topographical features, endothelial cells tune their ability to populate target substrates, both in vivo and in vitro. Basal textures interfere with the establishment and maturation of focal adhesions (FAs) thus inducing specific cell-polarization patterns and regulating a plethora of cell activities that govern the overall endothelial function. In this study, we analyze the effect of topographical features on FAs in primary human endothelial cells. Reported data demonstrate a functional link between FA dynamics and cell polarization and spreading on structured substrates presenting variable lateral feature size. Our results reveal that gratings with 2 µm lateral periodicity maximize contact guidance. The effect is linked to the dynamical state of FAs. We argue that these results are readily applicable to the rational design of active surfaces at the interface with the blood stream. PMID:26106866

  9. Wasp-waist populations and marine ecosystem dynamics: Navigating the “ predator pit” topographies

    NASA Astrophysics Data System (ADS)

    Bakun, Andrew

    2006-02-01

    Many marine ecosystems exhibit a characteristic “wasp-waist” structure, where a single species, or at most several species, of small planktivorous fishes entirely dominate their trophic level. These species have complex life histories that result in radical variability that may propagate to both higher and lower trophic levels of the ecosystem. In addition, these populations have two key attributes: (1) they represent the lowest trophic level that is mobile, so they are capable of relocating their area of operation according to their own internal dynamics; (2) they may prey upon the early life stages of their predators, forming an unstable feedback loop in the trophic system that may, for example, precipitate abrupt regime shifts. Experience with the typical “boom-bust” dynamics of this type of population, and with populations that interact trophically with them, suggests a “predator pit” type of dynamics. This features a refuge from predation when abundance is very low, very destructive predation between an abundance level sufficient to attract interest from predators and an abundance level sufficient to satiate available predators, and, as abundance increases beyond this satiation point, decreasing specific predation mortality and population breakout. A simple formalism is developed to describe these dynamics. Examples of its application include (a) a hypothetical mechanism for progressive geographical habitat expansion at high biomass, (b) an explanation for the out-of-phase alternations of abundances of anchovies and sardines in many regional systems that appear to occur without substantial adverse interactions between the two species groups, and (c) an account of an interaction of environmental processes and fishery exploitation that caused a regime shift. The last is the example of the Baltic Sea, where the cod resource collapsed in concert with establishment of dominance of that ecosystem by the cod’s ‘wasp-waist” prey, herring and sprat.

  10. Forecasting spatial plant dynamics under future climate change in a semiarid savanna ecosystem with complex topography

    NASA Astrophysics Data System (ADS)

    Zhou, X.; Fatichi, S.; Istanbulluoglu, E.; Vivoni, E. R.

    2011-12-01

    The space and time dynamics of savanna ecosystems in semiarid regions is tightly related to fluctuations and changes in the climate, and the competition strategies of individual plants for resources. In most parts of the southwest U.S., various General Circulation Models (GCMs) predict general warming trends with reduced annual precipitation amounts, and increased frequency of extreme droughts and wet periods in the 21st century. Despite the potential risks posed by climate change on vegetation patterns and hydrology, our ability to predict such changes at the catchment and regional scales is limited. In this study, we used a recently developed spatially explicit Cellular Automata Tree-Grass-Shrub Simulator (CATGraSS) to investigate the impacts of climate change on plant dynamics in a semiarid catchment (>3km2) located in the Sevilleta National Wildlife Refuge (SNWR) in central New Mexico, USA. In the catchment north-facing slopes are characterized by a juniper-grass savanna, and south-facing slopes by creosote bush and grass species. Initialized by LIDAR-derived tree locations and simulated grass and shrub patterns obtained from model calibration, CATGraSS is forced by a weather generator, AWE-GEN, used to downscale an ensemble of eight different GCM outputs at the study basin, producing multiple stochastic realizations of a transient climate scenario for the next hundred years. The ensemble simulations are used to examine the uncertainty in vegetation response and develop probabilistic plant distribution maps in relation to landscape morphology. This study highlights the importance of understanding local scale plant-to-plant interactions and the role of climate variability in determining climate change impacts on vegetation dynamics at varying spatial scales.

  11. Mariner 9 - An instrument of dynamical science. [for Mars gravitation and topography

    NASA Technical Reports Server (NTRS)

    Jordan, J. F.; Lorell, J.

    1975-01-01

    We review and evaluate the contributions of Mariner 9 in improving our knowledge of the dynamical characteristics of Mars and its two satellites, Phobos and Deimos. Primary results include the discovery of the large gravitational and topographical bulge in the Tharsis region, the development of a detailed gravity model representable as coefficients in a spherical harmonic expansion, the development of a topographic model exhibiting a three kilometer displacement of the center of figure from the center of mass, and the determination of the size, shape and motion of Phobos and Deimos.

  12. Interaction Between the Basin-Scale and Mesoscale Dynamics of the Black Sea: Impacts of Wind Forcing and Bottom Topography

    NASA Astrophysics Data System (ADS)

    Zatsepin, A. G.; Kremenetskiy, V. V.; Ratner, Y. B.; Stanichny, S. V.

    2008-12-01

    The general element of the classical theory of the Black Sea basin-scale circulation is the Rim current (RC) flowing cyclonically along the continental slope. Broad oceanographic application of the satellite data during the past decades has also revealed energetic mesoscale eddy-like structures that provide an effective cross- basin exchange. The aim of this report is to describe and discuss physical mechanisms of interaction between the RC and mesoscale eddies and their dependences on wind forcing and bottom topography. The study was based on the analysis of field observations and results of laboratory modeling. It was revealed by observations that in the northeastern Black Sea, having a very narrow continental slope, the topographic control of RC is weaker. The position and stability of RC is governed by the Ekman pumping. Under the strong (positive) Ekman pumping, which is more typical for the winter period, RC is a coherent and strong jet located over the continental slope. In this case, the lateral, cross-jet, exchange is relatively weak as the coastal and deep waters are separated by the dynamical front. In the alternative case of weak Ekman pumping, which is more typical for the Spring-Summer time, RC becomes unstable, meanders and breaks up into eddies producing strong lateral exchange. The effects of the wind forcing and bottom topography on the along-shore current, dynamically similar to RC, were studied in the laboratory experiment with the two-layer fluid in circular tank placed on the rotating table. It was shown that in case, when the width L of the continental slope is smaller or equal to the baroclinic Rossby deformation radius R, the influence of the bottom topography on the stability and structure of the along-shore current was negligible. After the decline or termination of the wind forcing, the along-shore current shifted in the off-shore direction, became unstable and disintegrated into eddies, providing an intensive water exchange between the

  13. A New Clinical Instrument for The Early Detection of Cataract Using Dynamic Light Scattering and Corneal Topography

    NASA Technical Reports Server (NTRS)

    Ansari, Rafat R.; Datiles, Manuel B., III; King, James F.

    2000-01-01

    A growing cataract can be detected at the molecular level using the technique of dynamic light scattering (DLS). However, the success of this method in clinical use depends upon the precise control of the scattering volume inside a patient's eye and especially during patient's repeat visits. This is important because the scattering volume (cross-over region between the scattered fight and incident light) inside the eye in a high-quality DLS set-up is very small (few microns in dimension). This precise control holds the key for success in the longitudinal studies of cataract and during anti-cataract drug screening. We have circumvented these problems by fabricating a new DLS fiber optic probe with a working distance of 40 mm and by mounting it inside a cone of a corneal analyzer. This analyzer is frequently used in mapping the corneal topography during PRK (photorefractive keratectomy) and LASIK (laser in situ keratomileusis) procedures in shaping of the cornea to correct myopia. This new instrument and some preliminary clinical tests on one of us (RRA) showing the data reproducibility are described.

  14. Improving Surface Geostrophic Current from a GOCE-Derived Mean Dynamic Topography Using Edge-Enhancing Diffusion Filtering

    NASA Astrophysics Data System (ADS)

    Sánchez-Reales, J. M.; Andersen, O. B.; Vigo, M. I.

    2016-03-01

    With increased geoid resolution provided by the gravity and steady-state ocean circulation explorer (GOCE) mission, the ocean's mean dynamic topography (MDT) can be now estimated with an accuracy not available prior to using geodetic methods. However, an altimetric-derived MDT still needs filtering in order to remove short wavelength noise unless integrated methods are used in which the three quantities are determined simultaneously using appropriate covariance functions. We studied nonlinear anisotropic diffusive filtering applied to the oceańs MDT and a new approach based on edge-enhancing diffusion (EED) filtering is presented. EED filters enable controlling the direction and magnitude of the filtering, with subsequent enhancement of computations of the associated surface geostrophic currents (SGCs). Applying this method to a smooth MDT and to a noisy MDT, both for a region in the Northwestern Pacific Ocean, we found that EED filtering provides similar estimation of the current velocities in both cases, whereas a non-linear isotropic filter (the Perona and Malik filter) returns results influenced by local residual noise when a difficult case is tested. We found that EED filtering preserves all the advantages that the Perona and Malik filter have over the standard linear isotropic Gaussian filters. Moreover, EED is shown to be more stable and less influenced by outliers. This suggests that the EED filtering strategy would be preferred given its capabilities in controlling/preserving the SGCs.

  15. Equilibrium and Dynamic Vortex States near Absolute Zero in a Weak Pinning Amorphous Film

    NASA Astrophysics Data System (ADS)

    Ochi, Aguri; Sohara, Naoya; Kaneko, Shin-ichi; Kokubo, Nobuhito; Okuma, Satoshi

    2016-04-01

    By developing and employing a mode-locking measurement with pulsed currents, we successfully determine the dynamic melting field B{c,dyn}∞ (T) for a driven vortex lattice of an amorphous MoxGe1-x film in the limit of zero temperature (T → 0) and complete a dynamic as well as a static vortex phase diagram. At T = 0, the mixed state in the absence of pinning comprises vortex-lattice and quantum-vortex-liquid (QVL) phases, and the melting field separating the two phases is identified as B{c,dyn}∞ (0). Comparison of the dynamic and static phase diagrams reveals that, when the weak pinning is introduced into the pin-free system, a disordered phase emerges just above the vortex-lattice phase and a threshold field separating the two phases is slightly suppressed from B{c,dyn}∞ (0), indicative of defect-induced disordering of the lattice. By contrast, a melting field into QVL is much enhanced from B{c,dyn}∞ (0) up to a point near the upper critical field, resulting in a significant suppression of the QVL phase. This is attributed to the stronger effective pinning at lower T, which survives quantum fluctuations.

  16. Determination of some dominant parameters of the global dynamic sea surface topography from GEOS-3 altimetry

    NASA Technical Reports Server (NTRS)

    Mather, R. S.; Lerch, F. J.; Rizos, C.; Masters, E. G.; Hirsch, B.

    1978-01-01

    The 1977 altimetry data bank is analyzed for the geometrical shape of the sea surface expressed as surface spherical harmonics after referral to the higher reference model defined by GEM 9. The resulting determination is expressed as quasi-stationary dynamic SST. Solutions are obtained from different sets of long arcs in the GEOS-3 altimeter data bank as well as from sub-sets related to the September 1975 and March 1976 equinoxes assembled with a view to minimizing seasonal effects. The results are compared with equivalent parameters obtained from the hydrostatic analysis of sporadic temperature, pressure and salinity measurements of the oceans and the known major steady state current systems with comparable wavelengths. The most clearly defined parameter (the zonal harmonic of degree 2) is obtained with an uncertainty of + or - 6 cm. The preferred numerical value is smaller than the oceanographic value due to the effect of the correction for the permanent earth tide. Similar precision is achieved for the zonal harmonic of degree 3. The precision obtained for the fourth degree zonal harmonic reflects more closely the accuracy expected from the level of noise in the orbital solutions.

  17. Sea surface height and dynamic topography of the ice-covered oceans from CryoSat-2: 2011-2014

    NASA Astrophysics Data System (ADS)

    Kwok, Ron; Morison, James

    2016-01-01

    We examine 4 years (2011-2014) of sea surface heights (SSH) from CryoSat-2 (CS-2) over the ice-covered Arctic and Southern Oceans. Results are from a procedure that identifies and determines the heights of sea surface returns. Along 25 km segments of satellite ground tracks, variability in the retrieved SSHs is between ˜2 and 3 cm (standard deviation) in the Arctic and is slightly higher (˜3 cm) in the summer and the Southern Ocean. Average sea surface tilts (along these 25 km segments) are 0.01 ± 3.8 cm/10 km in the Arctic, and slightly lower (0.01 ± 2.0 cm/10 km) in the Southern Ocean. Intra-seasonal variability of CS-2 dynamic ocean topography (DOT) in the ice-covered Arctic is nearly twice as high as that of the Southern Ocean. In the Arctic, we find a correlation of 0.92 between 3 years of DOT and dynamic heights (DH) from hydrographic stations. Further, correlation of 4 years of area-averaged CS-2 DOT near the North Pole with time-variable ocean-bottom pressure from a pressure gauge and from GRACE, yields coefficients of 0.83 and 0.77, with corresponding differences of <3 cm (RMS). These comparisons contrast the length scale of baroclinic and barotropic features and reveal the smaller amplitude barotropic signals in the Arctic Ocean. Broadly, the mean DOT from CS-2 for both poles compares well with those from the ICESat campaigns and the DOT2008A and DTU13MDT fields. Short length scale topographic variations, due to oceanographic signals and geoid residuals, are especially prominent in the Arctic Basin but less so in the Southern Ocean.

  18. Extracting dynamic topography from river profiles and cosmogenic nuclide geochronology in the Middle Atlas and the High Plateaus of Morocco

    NASA Astrophysics Data System (ADS)

    Pastor, Alvar; Babault, Julien; Owen, Lewis A.; Teixell, Antonio; Arboleya, María-Luisa

    2015-11-01

    The Moulouya river system has intensely eroded the Arhbalou, Missour, and Guercif Neogene foreland basins in northeastern Morocco, having changed from net aggradation during the Miocene-early Pliocene to net incision punctuated by alluvial fan deposition at late Pliocene or early Quaternary time. This region as a whole has experienced mantle-driven, surface uplift (dynamic topography) since the late Cenozoic, being locally affected by uplift due to crustal shortening and thickening of the Middle Atlas too. Knickpoints located along the major streams of the Moulouya fluvial network, appear on both the undeformed margins of the Missour and Guercif foreland basins (High Plateaus), as well as along the thrust mountain front of the southern Middle Atlas, where they reach heights of 800-1000 m. 500-550 m of the knickpoint vertical incision might be explained by long-wavelength mantle-driven dynamic surface uplift, whereas the remaining 450-500 m in the southern Middle Atlas front and 200-300 m in the northeastern Middle Atlas front seem to be thrust-related uplift of the Jebel Bou Naceur. Be-10 terrestrial cosmogenic nuclides have been used to date two Quaternary river terraces in the Chegg Ard valley at 62 ± 14 ka and 411 ± 55 ka. The dated terraces allow the incision rates associated with the frontal structures of the Middle Atlas to be estimated at ~ 0.3 mm yr- 1. Furthermore, these ages have served to evaluate mantle-driven regional surface uplift since the middle Pleistocene in the central Missour basin, yielding values of ~ 0.1-0.2 mm yr- 1.

  19. How topography induces reproductive asynchrony and alters gypsy moth invasion dynamics.

    PubMed

    Walter, Jonathan A; Meixler, Marcia S; Mueller, Thomas; Fagan, William F; Tobin, Patrick C; Haynes, Kyle J

    2015-01-01

    potentially be important to the population dynamics of many organisms. PMID:25039257

  20. Coseismic temporal changes of slip direction: the effect of absolute stress on dynamic rupture

    USGS Publications Warehouse

    Guatteri, Mariagiovanna; Spudich, P.

    1998-01-01

    We investigate the dynamics of rupture at low-stress level. We show that one main difference between the dynamics of high- and low-stress events is the amount of coseismic temporal rake rotation occurring at given points on the fault. Curved stations on exposed fault surfaces and earthquake dislocation models derived from ground-motion inversion indicate that the slip direction may change with time at a pointon the fault during dynamic rupture. We use a 3D boundary integral method to model temporal rake variations during dynamic rupture propagation assuming a slip-weakening friction law and isotropic friction. The points at which the slip rotates most are characterized by an initial shear stress direction substantially different from the average stress direction over the fault plane. We show that for a given value of stress drop, the level of initial shear stress (i.e., the fractional stress drop) determines the amount of rotation in slip direction. We infer that seismic events that show evidence of temporal rake rorations are characterized by a low initial shear-stress level with spatially variable direction on the fault (possibly due to changes in fault surface geometry) and an almost complete stress drop. Our models motivate a new interpretation of curved and cross-cutting striations and put new constraints on their analysis. The initial rake is in general collinear with the initial stress at the hypocenter zone, supporting the assumptions made in stress-tensor inversion from first-motion analysis. At other points on the fualt, especially away from the hypocenter, the initial slip rake may not be collinear with the initial shear stress, contradicting a common assumption of structural geology. On the other hand, the later part of slip in our models is systematically more aligned withi the average stress direction than the early slip. Our modeling suggests that the length of the straight part of curved striations is usually an upper bound of the slip

  1. Dynamic topography of the southern Central Anatolian Plateau, Turkey, and geodynamic driving mechanisms

    NASA Astrophysics Data System (ADS)

    Schildgen, T. F.; Cosentino, D.; Dudas, F. O.; Niedermann, S.; Strecker, M. R.; Echler, H.; Yildirim, C.

    2010-12-01

    Collision between Eurasia and Arabia and subsequent westward extrusion of the Anatolian microplate explains the development of major intracontinental fault systems in Anatolia that have remained active to the present-day. Concurrent, and probable episodic uplift of the Central and Eastern Anatolian plateaus (CAP and EAP), however, suggests that additional geodynamic mechanisms have contributed to the late Cenozoic morphologic development of the region. Sedimentary basins spanning the southern margin of the CAP provide insights on the timing and rates of different phases of surface uplift, giving constraints to test which geodynamic processes have contributed to surface uplift, orogenic plateau growth, and coupled landscape/climate evolution. Stratigraphic and geomorphic records of uplift and subsidence in the Mut Basin at the southern CAP margin and along the Göksu River record dynamic topographic development. Biostratigraphy and Sr isotope stratigraphy on the highest (ca. 2 km) uplifted marine sediments of the Mut basin furnish a maximum age of ca. 8 Ma for the onset of late Cenozoic uplift of the region. A Pliocene to early Pleistocene marine section, inset within the older stratigraphy at ca. 0.2 to 1.2 km elevation, reveals a history of subsidence and renewed uplift, following the initial uplift that occurred between ca. 8 Ma and Pliocene time. The most recent phase of uplift continued with possibly minor interruptions during the Quaternary, and is recorded by a series of fluvial terraces preserved between 30 and 143 m above the modern Göksu River. One terrace (143 m) reveals a 21Ne model exposure age of ca. 160 ka; ongoing exposure age determination will further constrain the uplift history. Different geodynamic mechanisms have likely contributed to surface uplift along the southern CAP margin. Initial uplift may have been associated with the predominantly sinistral Ecemis fault system that spans the southern and southeastern CAP margin. Neogene counter

  2. The dynamics of a rigid body on an absolutely rough plane

    NASA Astrophysics Data System (ADS)

    Markeev, A. P.

    1983-08-01

    An attempt is made to explain certain dynamic effects associated with the rattleback, with particular emphasis placed on the oscillations of the body near the equilibrium position or near stationary rotation. The small oscillations of the body in the neighborhood of its stationary rotation about the vertical are analyzed; an approximate system of equations describing the nonlinear oscillations of the rattleback near its equilibrium position on a plane is derived; and a complete analysis of this system is given. The results agree with experimentally observed variations of the direction of the rotation of the body about the vertical in the absence of external influence and the appearance of rotation in both directions due to oscillations about the horizontal axis.

  3. Free Energy Perturbation Hamiltonian Replica-Exchange Molecular Dynamics (FEP\\H-REMD) for absolute ligand binding free energy calculations.

    SciTech Connect

    Jiang, W.; Roux, B.

    2010-09-01

    Free Energy Perturbation with Replica Exchange Molecular Dynamics (FEP/REMD) offers a powerful strategy to improve the convergence of free energy computations. In particular, it has been shown previously that a FEP/REMD scheme allowing random moves within an extended replica ensemble of thermodynamic coupling parameters '{lambda}' can improve the statistical convergence in calculations of absolute binding free energy of ligands to proteins [J. Chem. Theory Comput. 2009, 5, 2583]. In the present study, FEP/REMD is extended and combined with an accelerated MD simulations method based on Hamiltonian replica-exchange MD (H-REMD) to overcome the additional problems arising from the existence of kinetically trapped conformations within the protein receptor. In the combined strategy, each system with a given thermodynamic coupling factor {lambda} in the extended ensemble is further coupled with a set of replicas evolving on a biased energy surface with boosting potentials used to accelerate the interconversion among different rotameric states of the side chains in the neighborhood of the binding site. Exchanges are allowed to occur alternatively along the axes corresponding to the thermodynamic coupling parameter {lambda} and the boosting potential, in an extended dual array of coupled {lambda}- and H-REMD simulations. The method is implemented on the basis of new extensions to the REPDSTR module of the biomolecular simulation program CHARMM. As an illustrative example, the absolute binding free energy of p-xylene to the nonpolar cavity of the L99A mutant of the T4 lysozyme was calculated. The tests demonstrate that the dual {lambda}-REMD and H-REMD simulation scheme greatly accelerates the configurational sampling of the rotameric states of the side chains around the binding pocket, thereby improving the convergence of the FEP computations.

  4. Who is in control? Competing influences of geology, land use and topography on soil moisture and soil temperature dynamics

    NASA Astrophysics Data System (ADS)

    Blume, Theresa; Hassler, Sibylle; Weiler, Markus

    2014-05-01

    Can we identify distinct signatures of landscape elements in the event response of soil moisture and soil temperature? Moisture and temperature dynamics in soils are largely controlled by the climatic boundary conditions of rainfall, evapotranspiration and radiation. However, certain landscape features also leave characteristic finger prints on soil moisture and soil temperature time series. The extent of these influences and their time variable relative importance are important in a number of contexts, such as landscape scale prediction of soil moisture patterns or runoff generation, process predictions in ungauged basins or the improvement of hydrological model structures for the mesoscale. The competing influences of geology, land use and topography on temperature and moisture characteristics in the vadose zone are explored at the CAOS hydrological observatory in Luxemburg (http://www.caos-project.de/) with a unique experimental setup of 45 sensor clusters. These sensor clusters cover three different geologies (schist, sandstone, marls), two land use classes (forest and grassland), five different landscape positions (plateau, top-, mid- and lower hillslope as well as near stream/floodplain locations), and contrasting expositions. At each of these sensor clusters three soil moisture profiles with sensors at depths from 10 to 70 cm, four soil temperature profiles as well as air temperature, relative humidity, global radiation, rainfall/throughfall, sapflow and shallow groundwater and stream water levels were measured continuously. Time series of up to 2 years for the schist region and up to 6 months for the complete set of sites allow for a first intercomparison of characteristic event response behavior.

  5. Mid Pliocene sea levels: A combined analysis of field data, models of glacial isostasy and dynamic topography, and eustasy. (Invited)

    NASA Astrophysics Data System (ADS)

    Rovere, A.; Raymo, M. E.; Hearty, P. J.; Austermann, J.; Mitrovica, J. X.; Michael, O.; Moucha, R.; Forte, A. M.; Rowley, D. B.

    2013-12-01

    Determining the eustatic elevation of former sea levels (SL), or equivalently ice volumes, is a central goal of paleoclimate research. SL estimates for the Mid-Pliocene warm period (MPWP, ˜3.3 to 2.9 Ma) are of particular interest as CO2 levels at that time (between 350 and 450 ppmv) were similar to today (> 400 ppmv as of May 2013). However, despite general agreement on other climate variables, SL estimates for the MPWP and the stability of polar ice sheets during this interval remain largely unconstrained. In this regard, inferring ice volumes from SL indicators of MPWP age is complicated by several factors. First, relatively few robust records of MPWP SL have been obtained from tectonically stable areas. Second, the potentially significant contaminating signals due to glacial isostatic adjustment (GIA) and dynamic topography associated with mantle convective flow (DT) have rarely, and only recently, been accounted for. Within the framework of PLIOMAX project, we are collecting accurate MPWP indicators at widely distributed sites using a combination of classic field methods, state of the art GPS and GIS techniques. Moreover, the analysis of the data involves the participation of both field geologists and geodynamic modelers. In this talk, we present data collected in three specific areas: Republic of South Africa, Western Australia and the southeastern United States. We will report on the present day elevation of MPWP shoreline indicators in each region. Moreover, we will combine this data set with a broad suite of numerical models of GIA and DT to establish current uncertainties on the estimate of eustatic SL during the MPWP, as well as comment on possible strategies for improving the accuracy of this estimate.

  6. On the effect of the Post-perovskite phase change on global mantle flow, geoid and dynamic topography

    NASA Astrophysics Data System (ADS)

    Shahraki, Meysam; Schmeling, Harro; Kaban, Mikhail; Petrunin, Alexei

    2014-05-01

    In the lowermost parts of mantle, the D" layer is a profoundly important layer as it involves the process of heat and mass transfer between core and mantle. However, the physical nature of this layer is an issue of active debate. The seismic data represent a rapid increase and decrease of the shear velocity, especially beneath Circum-Pacific margins, in the D" layer. Indeed, such abrupt velocity discontinuity is not expected for this hot layer. The discovery of the perovskite (pv) to Post-perovskite (pPv) phase transformation has led to dramatic increase in our understanding of the structure of the D" layer, since it is thought to produce such seismic discontinuity. Here, we have investigate the influence of the phase transformation of pv to pPv on the geoid undulation as one of the most important geophysical observable, using 3D spherical shell mantle circulation models based on a seismic tomography model (S40RTS) and strongly lateral viscosity variations in the D" layer and the mantle above. We demonstrate that the geoid anomalies are strongly affected by the presence of pPv in the lowermost mantle. While the geoid heights over subduction zones are increased by considering a strong pPv compared to then surrounding mantle, a weak pPv reduces the geoid height, and a better fit to the observed geoid is obtained. We show that, applying a weak pPv viscosity of at least three orders of magnitude any higher viscosity contrast does not affect the geoid any further. We also investigate the effects of weak pPv combined with a different tomography model, a different pPv density contrast, the presence or absence of a global thermal-boundary-layer (TBL) and the presence or absence of lateral viscosity variations in the lower mantle. Keywords: Post-perovskite, phase transitions, geoid, dynamic topography

  7. Nuclear depolarization and absolute sensitivity in magic-angle spinning cross effect dynamic nuclear polarization.

    PubMed

    Mentink-Vigier, Frédéric; Paul, Subhradip; Lee, Daniel; Feintuch, Akiva; Hediger, Sabine; Vega, Shimon; De Paëpe, Gaël

    2015-09-14

    Over the last two decades solid state Nuclear Magnetic Resonance has witnessed a breakthrough in increasing the nuclear polarization, and thus experimental sensitivity, with the advent of Magic Angle Spinning Dynamic Nuclear Polarization (MAS-DNP). To enhance the nuclear polarization of protons, exogenous nitroxide biradicals such as TOTAPOL or AMUPOL are routinely used. Their efficiency is usually assessed as the ratio between the NMR signal intensity in the presence and the absence of microwave irradiation εon/off. While TOTAPOL delivers an enhancement εon/off of about 60 on a model sample, the more recent AMUPOL is more efficient: >200 at 100 K. Such a comparison is valid as long as the signal measured in the absence of microwaves is merely the Boltzmann polarization and is not affected by the spinning of the sample. However, recent MAS-DNP studies at 25 K by Thurber and Tycko (2014) have demonstrated that the presence of nitroxide biradicals combined with sample spinning can lead to a depolarized nuclear state, below the Boltzmann polarization. In this work we demonstrate that TOTAPOL and AMUPOL both lead to observable depolarization at ≈110 K, and that the magnitude of this depolarization is radical dependent. Compared to the static sample, TOTAPOL and AMUPOL lead, respectively, to nuclear polarization losses of up to 20% and 60% at a 10 kHz MAS frequency, while Trityl OX63 does not depolarize at all. This experimental work is analyzed using a theoretical model that explains how the depolarization process works under MAS and gives new insights into the DNP mechanism and into the spin parameters, which are relevant for the efficiency of a biradical. In light of these results, the outstanding performance of AMUPOL must be revised and we propose a new method to assess the polarization gain for future radicals. PMID:26235749

  8. Comparing the effects of rheology on the dynamics and topography of 3D subduction-collision models

    NASA Astrophysics Data System (ADS)

    Pusok, Adina E.; Kaus, Boris; Popov, Anton

    2015-04-01

    Most of the major mountain belts and orogenic plateaus are found within the overlying plate of active or fossil subduction and/or collision zones. It is well known that they evolve differently from one another as the result of specific combinations of surface and mantle processes. The differences among the structures and evolutions of mountain belts arise for several reasons, such as different strengths of materials, different amounts of regional isostatic compensation, and different mechanisms by which forces are applied to the convergence plates. All these possible controlling factors can change with space and time. Of all the mountain belts and orogenic plateaus, the most striking example is the India-Asia collision zone, which gave rise to the Himalayas and the Tibetan Plateau, the largest region of elevated topography and anomalously thick crust on Earth. Understanding the formation and evolution of such a highly elevated region has been the focus of many tectonic and numerical models. While some of these models (i.e. thin sheet model) have successfully illustrated some of the basic physics of continental collision, none can simultaneously represent active processes such as subduction, underthrusting, channel flow or extrusion, for which fully 3D models are required. Here, we employed the 3D code LaMEM to investigate the role that subduction, continental collision and indentation play on lithosphere dynamics at convergent margins, and the implications they have for the Asian tectonics. Our model setup resembles a simplified tectonic map of the India-Asia collision zone and we performed long-term 3D simulations to analyse the dynamics and the conditions under which large topographic plateaus, such as the Tibetan Plateau can form in an integrated lithospheric and upper-mantle scale model. Results of models with linear viscous rheologies show different modes between the oceanic subduction side (continuous subduction, trench retreat and slab roll-back) and the

  9. Influence of bottom topography on dynamics of river plumes in semi-enclosed domains: Case study in Taiwan Strait

    NASA Astrophysics Data System (ADS)

    Zavialov, Peter; Korotenko, Konstantin; Osadchiev, Alexander; Kao, Ruei-Chi; Ding, Chung-Feng

    2014-05-01

    This paper summarizes the results of a Russian-Taiwan research project focused on the role of continental discharges into the Taiwan Strait, an important channel in the western Pacific Ocean transporting water between the South China Sea and the East China Sea. Another critically important hydrographic feature in the area is the discharge of freshwater from multiple rivers of the western coast of Taiwan. With its long-term average discharge rate of 210 m3/s, the Zhuoshui River is the biggest of the rivers bringing a large amount of pollutants and nutrients into the Strait. The northern extremity of Zhuoshui River's plume often merges with that of the Wu River (also known as Dudu River) whose average discharge rate is about 120 m3/s. Oceanic waters in the area experience significant anthropogenic pressures, traceable to the distance of a few km offshore and tens of km along the shore. This is manifested, in particular, in strongly elevated concentrations of copper, iron, and other trace metals. The corresponding quantitative estimates are obtained. The newly obtained in situ data from a field campaign were also used to implement 2 numerical models aimed at simulating the pathways of the continental waters in the study region. One of them, based on the Princeton Ocean Model, was coupled with a regional barotropic tidal model for the Taiwan Strait. The other one, a fully Lagrangian model STRiPE is based on applying a complete set of momentum equations to individual "particles" of river water released into the ocean. Both models demonstrated reasonable good agreement with the in situ data and each other. The bathymetry, tides and winds significantly affect the dynamics of the Wu and Zhuoshui river plumes, acting together in a complex interactive manner. The Zhuoshui River plume stretches in a narrow alongshore belt both to the south and north from the river mouth while the larger, round-shaped Wu River's plume elongates mostly north of its mouth. The difference is

  10. Introducing variable-step topography (VST) coordinates within dynamically constrained nonhydrostatic modeling system (NMS). Part 2: VST performance on orthodox obstacle flows

    NASA Astrophysics Data System (ADS)

    Tripoli, Gregory J.; Smith, Eric A.

    2014-06-01

    In this second part of a two-part sequence of papers, the performance metrics and quantitative advantages of a new VST surface coordinate system, implemented within a dynamically constrained, nonhydrostatic, cloud mesoscale atmospheric model, are evaluated in conjunction with seven orthodox obstacle flow problems. [The first part presented a full formulation of the VST model, prefaced by a description of the framework of the newly re-tooled nonhydrostatic modeling system (NMS) operating within integral constraints based on the conservation of the foremost quantities of mass, energy and circulation.] The intent behind VST is to create a vertical surface coordinate system boundary underpinning a nonhydrostatic atmosphere capable of reliable simulations of flows over both smooth and steep terrain without sacrificing dynamical integrity over either type of surface. Model simulation results are analyzed for six classical fluid dynamics problems involving flows relative to obstacles with known analytical or laboratory-simulated solutions, as well as for a seventh noteworthy mountain wave breaking problem that has well-studied numerical solutions. For cases when topography becomes excessively severe or poorly resolved numerically, atmospheric models using transform (terrain-following) coordinates produce noteworthy errors rendering a stable integration only if the topography is smoothed. For cases when topography is slowly varying (smooth or subtle), models using discrete-step coordinates also produce noteworthy errors relative to known solutions. Alternatively, the VST model demonstrates that both limitations of the two conventional approaches, for the entire range of slope severities, can be overcome. This means that VST is ideally suited for a scalable, nonhydrostatic atmospheric model, safeguarded with physically realistic dynamical constraints.

  11. The structure and dynamics of coherent vortex tubes in rotating shear turbulence of zero-mean-absolute vorticity.

    NASA Astrophysics Data System (ADS)

    Tanaka, Mitsuru; Yanase, Shinichiro

    2010-05-01

    The effect of the system rotation on shear flow turbulence is one of the central issues of fluid mechanics in relation to geophysical and astrophysical phenomena as well as engineering applications such as turbo machinery, so is still being vigorously investigated. If a turbulent shear flow is rotated as a whole about the axis parallel to the mean-shear vorticity, the flow structure is significantly influenced by the magnitude and direction of vorticity associated with the mean shear relative to those of the system rotation. The flow field is called either cyclonic or anti-cyclonic accordingly as vorticities associated with the mean shear and the system rotation are parallel or anti-parallel. Turbulence has a tendency to keep its two-dimensional structure along the system rotation both for cyclonic and for an anti-cyclonic regions for rapid system rotation, whereas the two-dimensional structure is unstable and easily broken down to three-dimensional in an anti-cyclonic region if the system rotation is relatively slow to the mean-shear vorticity. If the flow field is anti-cyclonic and the mean-shear vorticity cancels out that of the system rotation, the mean absolute vorticity is zero in the flow field, and then it is called the zero-mean-absolute-vorticity state (ZAVS). ZAVS, which is neutral to the above-mentioned instability, is observed in many rotating shear flow turbulence. One of the most remarkable features of ZAVS turbulence is the generation of very coherent quasi-streamwise vortex tubes which are not observed in other cases of rotating or nonrotating turbulence. Though the importance of the role of vortex tubes in shear flow turbulence is generally recognized, it is not easy to study their dynamics due to the interactions between vortex tubes and vortex-shear layers which are generated from the background mean-shear vorticity. In ZAVS, on the other hand, it is rather easy to investigate vortex tubes in turbulence because they are stable and long

  12. Constraining the Absolute Orientation of eta Carinae's Binary Orbit: A 3-D Dynamical Model for the Broad [Fe III] Emission

    NASA Technical Reports Server (NTRS)

    Madura, T. I.; Gull, T. R.; Owocki, S. P.; Groh, J. H.; Okazaki, A. T.; Russell, C. M. P.

    2011-01-01

    We present a three-dimensional (3-D) dynamical model for the broad [Fe III] emission observed in Eta Carinae using the Hubble Space Telescope/Space Telescope Imaging Spectrograph (HST/STIS). This model is based on full 3-D Smoothed Particle Hydrodynamics (SPH) simulations of Eta Car's binary colliding winds. Radiative transfer codes are used to generate synthetic spectro-images of [Fe III] emission line structures at various observed orbital phases and STIS slit position angles (PAs). Through a parameter study that varies the orbital inclination i, the PA(theta) that the orbital plane projection of the line-of-sight makes with the apastron side of the semi-major axis, and the PA on the sky of the orbital axis, we are able, for the first time, to tightly constrain the absolute 3-D orientation of the binary orbit. To simultaneously reproduce the blue-shifted emission arcs observed at orbital phase 0.976, STIS slit PA = +38deg, and the temporal variations in emission seen at negative slit PAs, the binary needs to have an i approx. = 130deg to 145deg, Theta approx. = -15deg to +30deg, and an orbital axis projected on the sky at a P A approx. = 302deg to 327deg east of north. This represents a system with an orbital axis that is closely aligned with the inferred polar axis of the Homunculus nebula, in 3-D. The companion star, Eta(sub B), thus orbits clockwise on the sky and is on the observer's side of the system at apastron. This orientation has important implications for theories for the formation of the Homunculus and helps lay the groundwork for orbital modeling to determine the stellar masses.

  13. Determination of absolute configuration in chiral solvents with nuclear magnetic resonance. A combined molecular dynamics/quantum chemical study.

    PubMed

    Kessler, Jiří; Dračínský, Martin; Bouř, Petr

    2015-05-28

    Nuclear magnetic resonance (NMR) spectroscopy is omnipresent in chemical analysis. However, chirality of a molecule can only be detected indirectly by NMR, e.g., by monitoring its interaction with another chiral object. In the present study, we investigate the spectroscopic behavior of chiral molecules placed into a chiral solvent. In this case, the solvent-solute interaction is much weaker, but the application range of such NMR analysis is wider than for a specific chemical shift agent. Two alcohols and an amine were used as model systems, and differences in NMR chemical shifts dependent on the solute-solvent chirality combination were experimentally detected. Combined quantum mechanic/molecular mechanic (QM/MM) computations were applied to reveal the underlying solute-solvent interactions. NMR shielding was calculated using the density functional theory (DFT). While the experimental observations could not be reproduced quantitatively, the modeling provided a qualitative agreement and detailed insight into the essence of solvent-solute chiral interactions. The potentials of mean force (PMF) obtained using molecular dynamics (MD) and the weighted histogram analysis method (WHAM) indicate that the chiral interaction brings about differences in conformer ratios, which are to a large extent responsible for the NMR shifts. The MD results also predicted slight changes in the solvent structure, including the radial distribution function (RDF), to depend on the solvent/solute chirality combination. Apart from the conformer distribution, an effective average solvent electrostatic field was tested as another major factor contributing to the chiral NMR effect. The possibility to simulate spectral effects of chiral solvents from the first-principles opens up the way to NMR spectroscopic determination of the absolute configuration for a larger scale of compounds, including those not forming specific complexes. PMID:25411905

  14. Absolute Zero

    NASA Astrophysics Data System (ADS)

    Donnelly, Russell J.; Sheibley, D.; Belloni, M.; Stamper-Kurn, D.; Vinen, W. F.

    2006-12-01

    Absolute Zero is a two hour PBS special attempting to bring to the general public some of the advances made in 400 years of thermodynamics. It is based on the book “Absolute Zero and the Conquest of Cold” by Tom Shachtman. Absolute Zero will call long-overdue attention to the remarkable strides that have been made in low-temperature physics, a field that has produced 27 Nobel Prizes. It will explore the ongoing interplay between science and technology through historical examples including refrigerators, ice machines, frozen foods, liquid oxygen and nitrogen as well as much colder fluids such as liquid hydrogen and liquid helium. A website has been established to promote the series: www.absolutezerocampaign.org. It contains information on the series, aimed primarily at students at the middle school level. There is a wealth of material here and we hope interested teachers will draw their student’s attention to this website and its substantial contents, which have been carefully vetted for accuracy.

  15. Constraining the absolute orientation of η Carinae's binary orbit: a 3D dynamical model for the broad [Fe III] emission

    NASA Astrophysics Data System (ADS)

    Madura, T. I.; Gull, T. R.; Owocki, S. P.; Groh, J. H.; Okazaki, A. T.; Russell, C. M. P.

    2012-03-01

    We present a three-dimensional (3D) dynamical model for the broad [Fe III] emission observed in η Carinae using the Hubble Space Telescope/Space Telescope Imaging Spectrograph (STIS). This model is based on full 3D smoothed particle hydrodynamics simulations of η Car's binary colliding winds. Radiative transfer codes are used to generate synthetic spectroimages of [Fe III] emission-line structures at various observed orbital phases and STIS slit position angles (PAs). Through a parameter study that varies the orbital inclination i, the PA θ that the orbital plane projection of the line of sight makes with the apastron side of the semimajor axis and the PA on the sky of the orbital axis, we are able, for the first time, to tightly constrain the absolute 3D orientation of the binary orbit. To simultaneously reproduce the blueshifted emission arcs observed at orbital phase 0.976, STIS slit PA =+38° and the temporal variations in emission seen at negative slit PAs, the binary needs to have an i≈ 130° to 145°, θ≈-15° to +30° and an orbital axis projected on the sky at a PA ≈ 302° to 327° east of north. This represents a system with an orbital axis that is closely aligned with the inferred polar axis of the Homunculus nebula, in 3D. The companion star, ηB, thus orbits clockwise on the sky and is on the observer's side of the system at apastron. This orientation has important implications for theories for the formation of the Homunculus and helps lay the groundwork for orbital modelling to determine the stellar masses. Footnotes<label>1</label>Low- and high-ionization refer here to atomic species with ionizations potentials (IPs) below and above the IP of hydrogen, 13.6 eV.<label>2</label>Measured in degrees from north to east.<label>3</label>θ is the same as the angle φ defined in fig. 3 of O08.<label>4</label>The outer edge looks circular only because this marks the edge of the spherical computational domain of the SPH simulation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140001041','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140001041"><span id="translatedtitle">Does <span class="hlt">Dynamical</span> Downscaling Introduce Novel Information in Climate Model Simulations of Recipitation Change over a Complex <span class="hlt">Topography</span> Region?</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Tselioudis, George; Douvis, Costas; Zerefos, Christos</p> <p>2012-01-01</p> <p>Current climate and future climate-warming runs with the RegCM Regional Climate Model (RCM) at 50 and 11 km-resolutions forced by the ECHAM GCM are used to examine whether the increased resolution of the RCM introduces novel information in the precipitation field when the models are run for the mountainous region of the Hellenic peninsula. The model results are inter-compared with the resolution of the RCM output degraded to match that of the GCM, and it is found that in both the present and future climate runs the regional models produce more precipitation than the forcing GCM. At the same time, the RCM runs produce increases in precipitation with climate warming even though they are forced with a GCM that shows no precipitation change in the region. The additional precipitation is mostly concentrated over the mountain ranges, where orographic precipitation formation is expected to be a dominant mechanism. It is found that, when examined at the same resolution, the elevation heights of the GCM are lower than those of the averaged RCM in the areas of the main mountain ranges. It is also found that the majority of the difference in precipitation between the RCM and the GCM can be explained by their difference in topographic height. The study results indicate that, in complex <span class="hlt">topography</span> regions, GCM predictions of precipitation change with climate warming may be dry biased due to the GCM smoothing of the regional <span class="hlt">topography</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010EGUGA..1212575G&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010EGUGA..1212575G&link_type=ABSTRACT"><span id="translatedtitle">Mantle convection, <span class="hlt">topography</span> and geoid</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Golle, Olivia; Dumoulin, Caroline; Choblet, Gaël.; Cadek, Ondrej</p> <p>2010-05-01</p> <p>The internal evolution of planetary bodies often include solid-state convection. This phenomenon may have a large impact on the various interfaces of these bodies (<span class="hlt">dynamic</span> <span class="hlt">topography</span> occurs). It also affects their gravity field (and the geoid). Since both geoid and <span class="hlt">topography</span> can be measured by a spacecraft, and are therefore available for several planetary bodies (while seismological measurements are still lacking for all of them but the Moon and the Earth), these are of the first interest for the study of internal structures and processes. While a classical approach now is to combine gravity and altimetry measurements to infer the internal structure of a planet [1], we propose to complement it by the reverse problem, i.e., producing synthetic geoid and <span class="hlt">dynamic</span> <span class="hlt">topography</span> from numerical models of convection as proposed by recent studies (e.g. for the CMB <span class="hlt">topography</span> of the Earth,[2]). This procedure first include a simple evaluation of the surface <span class="hlt">topography</span> and geoid from the viscous flow obtained by the 3D numerical tool OEDIPUS [3] modeling convection in a spherical shell. An elastic layer will then be considered and coupled to the viscous model - one question being whether the elastic shell shall be included 'on top' of the convective domain or within it, in the cold 'lithospheric' outer region. What we will present here corresponds to the first steps of this work: the comparison between the response functions of the <span class="hlt">topography</span> and the geoid obtained from the 3D convection program to the results evaluated by a spectral method handling radial variations of viscosity [4]. We consider the effect of the elastic layer whether included in the convective domain or not. The scale setting in the context of a full thermal convection model overlaid by an elastic shell will be discussed (thickness of the shell, temperature at its base...). References [1] A.M. Wieczorek, (2007), The gravity and <span class="hlt">topography</span> of the terrestrial planets, Treatise on Geophysics, 10, 165-206. [2</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19920037750&hterms=asthenosphere&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dasthenosphere','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19920037750&hterms=asthenosphere&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dasthenosphere"><span id="translatedtitle">Geoid anomalies and <span class="hlt">dynamic</span> <span class="hlt">topography</span> from convection in cylindrical geometry - Applications to mantle plumes on earth and Venus</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kiefer, Walter S.; Hager, Bradford H.</p> <p>1992-01-01</p> <p>A variety of evidence suggests that at least some hotspots are formed by quasi-cylindrical mantle plumes upwelling from deep in the mantle. Such plumes are modeled in cylindrical, axisymmetric geometry with depth-dependent, Newtonian viscosity. Cylindrical and sheet-like, Cartesian upwellings have significantly different geoid and <span class="hlt">topography</span> signatures. However, Rayleigh number-Nusselt number systematics in the two geometries are quite similar. The geoid anomaly and topographic uplift over a plume are insensitive to the viscosity of the surface layer, provided that it is at least 1000 times the interior viscosity. Increasing the Rayleigh number or including a low-viscosity asthenosphere decreases the geoid anomaly and the topographic uplift associated with an upwelling plume.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.T13B2380N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.T13B2380N"><span id="translatedtitle"><span class="hlt">Dynamic</span> <span class="hlt">topography</span> of the western Great Plains: landscape evidence for mantle-driven uplift associated with the Jemez lineament of NE New Mexico and SE Colorado</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nereson, A. L.; Karlstrom, K. E.; McIntosh, W. C.; Heizler, M. T.; Kelley, S. A.; Brown, S. W.</p> <p>2011-12-01</p> <p><span class="hlt">Dynamic</span> <span class="hlt">topography</span> results when viscous stresses created by flow within the mantle are transmitted through the lithosphere and interact with, and deform, the Earth's surface. Because <span class="hlt">dynamic</span> <span class="hlt">topography</span> is characterized by low amplitudes and long wavelengths, its subtle effects may be best recorded in low-relief areas such as the Great Plains of the USA where they can be readily observed and measured. We apply this concept to a unique region of the western Great Plains in New Mexico and Colorado where basalt flows of the Jemez lineament (Raton-Clayton and Ocate fields) form mesas (inverted <span class="hlt">topography</span>) that record the evolution of the Great Plains surface through time. This study uses multiple datasets to evaluate the mechanisms which have driven the evolution of this landscape. Normalized channel steepness index (ksn) analysis identifies anomalously steep river gradients across broad (50-100 km) convexities within a NE- trending zone of differential river incision where higher downstream incision rates in the last 1.5 Ma suggest headwater uplift. At 2-8 Ma timescales, 40Ar/39Ar ages of basalt-capped paleosurfaces in the Raton-Clayton and Ocate volcanic fields indicate that rates of denudation increase systematically towards the NW from a NE-trending zone of approximately zero denudation (that approximately coincides with the high ksn zone), also suggestive of regional warping above the Jemez lineament. Onset of more rapid denudation is observed in the Raton-Clayton field beginning at ca. 3.6 Ma. Furthermore, two 300-400-m-high NE-trending erosional escarpments impart a staircase-like topographic profile to the region. Tomographic images from the EarthScope experiment show that NE-trending topographic features of this region correspond to an ~8 % P-wave velocity gradient of similar trend at the margin of the low-velocity Jemez mantle anomaly. We propose that the erosional landscapes of this unique area are, in large part, the surface expression of <span class="hlt">dynamic</span> mantle</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015GGG....16.1771V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015GGG....16.1771V"><span id="translatedtitle"><span class="hlt">Dynamics</span> of intraoceanic subduction initiation: 2. Suprasubduction zone ophiolite formation and metamorphic sole exhumation in context of <span class="hlt">absolute</span> plate motions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>van Hinsbergen, Douwe J. J.; Peters, Kalijn; Maffione, Marco; Spakman, Wim; Guilmette, Carl; Thieulot, Cedric; Plümper, Oliver; Gürer, Derya; Brouwer, Fraukje M.; Aldanmaz, Ercan; Kaymakcı, Nuretdin</p> <p>2015-06-01</p> <p>Analyzing subduction initiation is key for understanding the coupling between plate tectonics and the underlying mantle. Here we focus on suprasubduction zone (SSZ) ophiolites and how their formation links to intraoceanic subduction initiation in an <span class="hlt">absolute</span> plate motion frame. SSZ ophiolites form the majority of exposed oceanic lithosphere fragments and are widely recognized to have formed during intraoceanic subduction initiation. Structural, petrological, geochemical, and plate kinematic constraints on their kinematic evolution show that SSZ crust forms at fore-arc spreading centers at the expense of a mantle wedge, thereby flattening the nascent slab. This leads to the typical inverted pressure gradients found in metamorphic soles that form at the subduction plate contact below and during SSZ crust crystallization. Former spreading centers are preserved in forearcs when subduction initiates along transform faults or off-ridge oceanic detachments. We show how these are reactivated when subduction initiates in the <span class="hlt">absolute</span> plate motion direction of the inverting weakness zone. Upon inception of slab pull due to, e.g., eclogitization, the sole is separated from the slab, remains welded to the thinned overriding plate lithosphere, and can become intruded by mafic dikes upon asthenospheric influx into the mantle wedge. We propound that most ophiolites thus formed under special geodynamic circumstances and may not be representative of normal oceanic crust. Our study highlights how far-field geodynamic processes and <span class="hlt">absolute</span> plate motions may force intraoceanic subduction initiation as key toward advancing our understanding of the entire plate tectonic cycle.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active"><span>7</span></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_7 --> <div id="page_8" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="141"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4878386','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4878386"><span id="translatedtitle">A Million-Plus Neuron Model of the Hippocampal Dentate Gyrus: Dependency of Spatio-Temporal Network <span class="hlt">Dynamics</span> on <span class="hlt">Topography</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Hendrickson, Phillip J.; Yu, Gene J.; Song, Dong; Berger, Theodore W.</p> <p>2016-01-01</p> <p>This paper describes a million-plus granule cell compartmental model of the rat hippocampal dentate gyrus, including excitatory, perforant path input from the entorhinal cortex, and feedforward and feedback inhibitory input from dentate interneurons. The model includes experimentally determined morphological and biophysical properties of granule cells, together with glutamatergic AMPA-like EPSP and GABAergic GABAA-like IPSP synaptic excitatory and inhibitory inputs, respectively. Each granule cell was composed of approximately 200 compartments having passive and active conductances distributed throughout the somatic and dendritic regions. Modeling excitatory input from the entorhinal cortex was guided by axonal transport studies documenting the topographical organization of projections from subregions of the medial and lateral entorhinal cortex, plus other important details of the distribution of glutamatergic inputs to the dentate gyrus. Results showed that when medial and lateral entorhinal cortical neurons maintained Poisson random firing, dentate granule cells expressed, throughout the million-cell network, a robust, non-random pattern of spiking best described as spatiotemporal “clustering”. To identify the network property or properties responsible for generating such firing “clusters”, we progressively eliminated from the model key mechanisms such as feedforward and feedback inhibition, intrinsic membrane properties underlying rhythmic burst firing, and/or topographical organization of entorhinal afferents. Findings conclusively identified topographical organization of inputs as the key element responsible for generating a spatio-temporal distribution of clustered firing. These results uncover a functional organization of perforant path afferents to the dentate gyrus not previously recognized: <span class="hlt">topography</span>-dependent clusters of granule cell activity as “functional units” that organize the processing of entorhinal signals. PMID:26737346</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26737346','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26737346"><span id="translatedtitle">A million-plus neuron model of the hippocampal dentate gyrus: Dependency of spatio-temporal network <span class="hlt">dynamics</span> on <span class="hlt">topography</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hendrickson, Phillip J; Yu, Gene J; Song, Dong; Berger, Theodore W</p> <p>2015-01-01</p> <p>This paper describes a million-plus granule cell compartmental model of the rat hippocampal dentate gyrus, including excitatory, perforant path input from the entorhinal cortex, and feedforward and feedback inhibitory input from dentate interneurons. The model includes experimentally determined morphological and biophysical properties of granule cells, together with glutamatergic AMPA-like EPSP and GABAergic GABAA-like IPSP synaptic excitatory and inhibitory inputs, respectively. Each granule cell was composed of approximately 200 compartments having passive and active conductances distributed throughout the somatic and dendritic regions. Modeling excitatory input from the entorhinal cortex was guided by axonal transport studies documenting the topographical organization of projections from subregions of the medial and lateral entorhinal cortex, plus other important details of the distribution of glutamatergic inputs to the dentate gyrus. Results showed that when medial and lateral entorhinal cortical neurons maintained Poisson random firing, dentate granule cells expressed, throughout the million-cell network, a robust, non-random pattern of spiking best described as spatiotemporal "clustering". To identify the network property or properties responsible for generating such firing "clusters", we progressively eliminated from the model key mechanisms such as feedforward and feedback inhibition, intrinsic membrane properties underlying rhythmic burst firing, and/or topographical organization of entorhinal afferents. Findings conclusively identified topographical organization of inputs as the key element responsible for generating a spatio-temporal distribution of clustered firing. These results uncover a functional organization of perforant path afferents to the dentate gyrus not previously recognized: <span class="hlt">topography</span>-dependent clusters of granule cell activity as "functional units" that organize the processing of entorhinal signals. PMID:26737346</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19790013321','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19790013321"><span id="translatedtitle">Problems in determining sea surface <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Whitehead, J. A., Jr.</p> <p>1978-01-01</p> <p>Anticipated problems for determining ocean <span class="hlt">dynamics</span> signals from sea surface <span class="hlt">topography</span> are discussed. The needs for repeated tracks are listed if oceanic tides or ocean turbulence are to be determined.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.T13D..07P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.T13D..07P"><span id="translatedtitle">Effects of rheology on the <span class="hlt">dynamics</span> and development of <span class="hlt">topography</span> in 3D numerical simulations of continental collision, with an application to the India-Asia collision zone</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pusok, A. E.; Kaus, B.; Popov, A.</p> <p>2014-12-01</p> <p>The Himalayas and the adjacent Tibetan Plateau represent the largest region of elevated <span class="hlt">topography</span> and anomalously thick crust on Earth. Understanding the formation and evolution of the region has been the focus of many tectonic and numerical models. While some of these models (i.e. thin sheet model) have successfully illustrated some of the basic physics of continental collision, none can simultaneously represent active processes such as subduction, underthrusting, channel flow or extrusion, for which fully 3D models are required. Here, we employed the 3D code LaMEM to investigate the role that subduction, continental collision and indentation play on lithosphere <span class="hlt">dynamics</span> at convergent margins, and the implications they have for the Asian tectonics. Our model setup resembles a simplified tectonic map of the India-Asia collision zone and we performed a large number of 3D simulations to analyse the <span class="hlt">dynamics</span> and the conditions under which large topographic plateaus, such as the Tibetan Plateau can form in an integrated lithospheric and upper-mantle scale model. Results of models with linear viscous rheologies show different modes between the oceanic subduction side (continuous subduction, trench retreat and slab roll-back) and the continental collision side (trench advance, slab detachment, topographic uplift and lateral extrusion of material). Despite the complex <span class="hlt">dynamics</span> and the great variation in slab shape across the subduction-collision zone, which are consistent with tomographic observations, we note that slab-pull alone is insufficient to generate high <span class="hlt">topography</span> in the upper plate. Several studies suggested that external forces (i.e. ridge push, plume push or slab suction) must be important in order to sustain the on-going convergence of India towards Eurasia. We show that external forcing and the presence of strong blocks such as the Tarim Basin within the Asian lithosphere are necessary to create and shape anomalously high topographic fronts and plateaus</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014DyAtO..66...28T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014DyAtO..66...28T"><span id="translatedtitle">Introducing Variable-Step <span class="hlt">Topography</span> (VST) coordinates within <span class="hlt">dynamically</span> constrained Nonhydrostatic Modeling System (NMS). Part 1: VST formulation within NMS host model framework</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tripoli, Gregory J.; Smith, Eric A.</p> <p>2014-06-01</p> <p>A Variable-Step <span class="hlt">Topography</span> (VST) surface coordinate system is introduced into a <span class="hlt">dynamically</span> constrained, scalable, nonhydrostatic atmospheric model for reliable simulations of flows over both smooth and steep terrain without sacrificing <span class="hlt">dynamical</span> integrity over either type of surface. Backgrounds of both terrain-following and step coordinate model developments are presented before justifying the turn to a VST approach within an appropriately configured host model. In this first part of a two-part sequence of papers, the full formulation of the VST model, prefaced by a description of the framework of its apposite host, i.e., a re-tooled Nonhydrostatic Modeling System (NMS), are presented. [The second part assesses the performance and benefits of the new VST coordinate system in conjunction with seven orthodox obstacle flow problems.] The NMS is a 3-dimensional, nonhydrostatic cloud-mesoscale model, designed for integrations from plume-cloud scales out to regional-global scales. The derivative properties of VST in conjunction with the NMS's newly designed <span class="hlt">dynamically</span> constrained core are capable of accurately capturing the deformations of flows by any type of terrain variability. Numerical differencing schemes needed to satisfy critical integral constraints, while also effectively enabling the VST lower boundary, are described. The host model constraints include mass, momentum, energy, vorticity and enstrophy conservation. A quasi-compressible closure cast on multiple-nest rotated spherical grids is the underlying framework used to study the advantages of the VST coordinate system. The principle objective behind the VST formulation is to combine the advantages of both terrain-following and step coordinate systems without suffering either of their disadvantages, while at the same time creating a vertical surface coordinate setting suitable for a scalable, nonhydrostatic model, safeguarded with physically realistic <span class="hlt">dynamical</span> constraints.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003AGUFM.B31C0321P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003AGUFM.B31C0321P"><span id="translatedtitle">Satellite Remote Sensing of Landscape Freeze/Thaw State <span class="hlt">Dynamics</span> for Complex <span class="hlt">Topography</span> and Fire Disturbance Areas Using Multi-Sensor Radar and SRTM Digital Elevation Models</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Podest, E.; McDonald, K.; Kimball, J.; Randerson, J. T.</p> <p>2003-12-01</p> <p>The annual freeze/thaw cycle drives the length of the growing season in the boreal forest, and is a major factor determining annual productivity and associated exchange of CO2 with the atmosphere. Variations in freeze/thaw processes are spatially and temporally complex in boreal environments, particularly in areas of complex <span class="hlt">topography</span> and in fire disturbance regimes. We investigate the spatial and temporal characteristics of seasonal freeze/thaw <span class="hlt">dynamics</span> in complex boreal landscapes, as derived from radar backscatter measured with ERS (C-band, VV polarization, 200m resolution) and JERS-1 (L-band, HH polarization, 100m resolution) Synthetic Aperture Radars (SARs), and with the SeaWinds scatterometer (Ku-band, 25km resolution). C- and L-band backscatter are applied to characterize freeze/thaw transitions for a chronosequence of recovering burn sites near Delta Junction, Alaska, and for a region of complex <span class="hlt">topography</span> on the Kenai Peninsula, Alaska. We characterize differences in radar-derived freeze/thaw state, examining transitions over complex terrain and landscape disturbance regimes. In areas of complex terrain, we explore freeze/thaw <span class="hlt">dynamics</span> related to elevation, slope aspect and varying landcover. In the burned regions, we explore the timing of seasonal freeze/thaw transition as related to the recovering landscape, relative to that of a nearby control site. We apply in situ biophysical measurements, including flux tower measurements to validate and interpret the remotely sensed parameters. A multi-scale analysis is performed relating high-resolution SAR backscatter and moderate resolution scatterometer measurements to assess trade-offs in spatial and temporal resolution in the remotely sensed fields. A temporal change discriminator is applied to classify time series radar imagery to classify the landscape freeze-thaw state. We apply a 30m-resolution digital elevation model (DEM) derived from Shuttle Radar <span class="hlt">Topography</span> Mission (SRTM) data to orthorectify the time</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004PhRvE..70a1911O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004PhRvE..70a1911O"><span id="translatedtitle">Spatially uniform and nonuniform analyses of electroencephalographic <span class="hlt">dynamics</span>,with application to the <span class="hlt">topography</span> of the alpha rhythm</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>O'Connor, S. C.; Robinson, P. A.</p> <p>2004-07-01</p> <p>Corticothalamic <span class="hlt">dynamics</span> are investigated using a model in which spatial nonuniformities are incorporated via the coupling of spatial eigenmodes. Comparison of spectra generated using the nonuniform analysis with those generated using a uniform one demonstrates that, for most frequencies, local activity is only weakly dependent on activity elsewhere in the cortex; however, dispersion of low-wave-number activity ensures that distant <span class="hlt">dynamics</span> influence local <span class="hlt">dynamics</span> at low frequencies (below approximately 2Hz ), and at the alpha frequency (approximately 10Hz ), where propagating signals are inherently weakly damped, and wavelengths are large. When certain model parameters have similar spatial profiles, as is expected from physiology, the low-frequency discrepancies tend to cancel, and the uniform analysis with local parameter values is an adequate approximation to the full nonuniform one across the whole spectrum, at least for large-scale nonuniformities. After comparing the uniform and nonuniform analyses, we consider one possible application of the nonuniform analysis: studying the phenomenon of occipital alpha dominance, whereby the alpha frequency and power are greater at the back of the head (occipitally) than at the front. In order to infer realistic nonuniformities in the model parameters, the uniform version of the model is first fitted to data recorded from 98 normal subjects in a waking, eyes-closed state. This yields a set of parameters at each of five electrode sites along the midline. The inferred parameter nonuniformities are consistent with anatomical and physiological constraints. Introducing these spatial profiles into the full nonuniform model then quantitatively reproduces observed site-dependent variations in the alpha power and frequency. The results confirm that the frequency shift is mainly due to a decrease in the corticothalamic propagation delay, but indicate that the delay nonuniformity cannot account for the observed occipital increase in</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AnPhy.326.1941A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AnPhy.326.1941A"><span id="translatedtitle">The analysis of space-time structure in QCD vacuum II: <span class="hlt">Dynamics</span> of polarization and <span class="hlt">absolute</span> X-distribution</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Alexandru, Andrei; Draper, Terrence; Horváth, Ivan; Streuer, Thomas</p> <p>2011-08-01</p> <p>We propose a framework for quantitative evaluation of <span class="hlt">dynamical</span> tendency for polarization in an arbitrary random variable that can be decomposed into a pair of orthogonal subspaces. The method uses measures based on comparisons of given <span class="hlt">dynamics</span> to its counterpart with statistically independent components. The formalism of previously considered X-distributions is used to express the aforementioned comparisons, in effect putting the former approach on solid footing. Our analysis leads to the definition of a suitable correlation coefficient with clear statistical meaning. We apply the method to the <span class="hlt">dynamics</span> induced by pure-glue lattice QCD in local left-right components of overlap Dirac eigenmodes. It is found that, in finite physical volume, there exists a non-zero physical scale in the spectrum of eigenvalues such that eigenmodes at smaller (fixed) eigenvalues exhibit convex X-distribution (positive correlation), while at larger eigenvalues the distribution is concave (negative correlation). This chiral polarization scale thus separates a regime where <span class="hlt">dynamics</span> enhances chirality relative to statistical independence from a regime where it suppresses it, and gives an objective definition to the notion of "low" and "high" Dirac eigenmode. We propose to investigate whether the polarization scale remains non-zero in the infinite volume limit, in which case it would represent a new kind of low energy scale in QCD.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015E%26PSL.421..107S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015E%26PSL.421..107S"><span id="translatedtitle">Australian plate motion and <span class="hlt">topography</span> linked to fossil New Guinea slab below Lake Eyre</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schellart, W. P.; Spakman, W.</p> <p>2015-07-01</p> <p>Unravelling causes for <span class="hlt">absolute</span> plate velocity change and continental <span class="hlt">dynamic</span> <span class="hlt">topography</span> change is challenging because of the interdependence of large-scale geodynamic driving processes. Here, we unravel a clear spatio-temporal relation between latest Cretaceous-Early Cenozoic subduction at the northern edge of the Australian plate, Early Cenozoic Australian plate motion changes and Cenozoic <span class="hlt">topography</span> evolution of the Australian continent. We present evidence for a ∼4000 km wide subduction zone, which culminated in ophiolite obduction and arc-continent collision in the New Guinea-Pocklington Trough region during subduction termination, coinciding with cessation of spreading in the Coral Sea, a ∼5 cm/yr decrease in northward Australian plate velocity, and slab detachment. Renewed northward motion caused the Australian plate to override the sinking subduction remnant, which we detect with seismic tomography at 800-1200 km depth in the mantle under central-southeast Australia at a position predicted by our <span class="hlt">absolute</span> plate reconstructions. With a numerical model of slab sinking and mantle flow we predict a long-wavelength subsidence (negative <span class="hlt">dynamic</span> <span class="hlt">topography</span>) migrating southward from ∼50 Ma to present, explaining Eocene-Oligocene subsidence of the Queensland Plateau, ∼330 m of late Eocene-early Oligocene subsidence in the Gulf of Carpentaria, Oligocene-Miocene subsidence of the Marion Plateau, and providing a first-order fit to the present-day, ∼200 m deep, topographic depression of the Lake Eyre Basin and Murray-Darling Basin. We propound that <span class="hlt">dynamic</span> <span class="hlt">topography</span> evolution provides an independent means to couple geological processes to a mantle reference frame. This is complementary to, and can be integrated with, other approaches such as hotspot and slab reference frames.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23489583','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23489583"><span id="translatedtitle">Neuronal correlates of decisions to speak and act: Spontaneous emergence and <span class="hlt">dynamic</span> <span class="hlt">topographies</span> in a computational model of frontal and temporal areas.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Garagnani, Max; Pulvermüller, Friedemann</p> <p>2013-10-01</p> <p>The neural mechanisms underlying the spontaneous, stimulus-independent emergence of intentions and decisions to act are poorly understood. Using a neurobiologically realistic model of frontal and temporal areas of the brain, we simulated the learning of perception-action circuits for speech and hand-related actions and subsequently observed their spontaneous behaviour. Noise-driven accumulation of reverberant activity in these circuits leads to their spontaneous ignition and partial-to-full activation, which we interpret, respectively, as model correlates of action intention emergence and action decision-and-execution. Importantly, activity emerged first in higher-association prefrontal and temporal cortices, subsequently spreading to secondary and finally primary sensorimotor model-areas, hence reproducing the <span class="hlt">dynamics</span> of cortical correlates of voluntary action revealed by readiness-potential and verb-generation experiments. This model for the first time explains the cortical origins and <span class="hlt">topography</span> of endogenous action decisions, and the natural emergence of functional specialisation in the cortex, as mechanistic consequences of neurobiological principles, anatomical structure and sensorimotor experience. PMID:23489583</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/456978','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/456978"><span id="translatedtitle">Fluorescence of excited charge-transfer complexes and <span class="hlt">absolute</span> <span class="hlt">dynamics</span> of radical-ion pairs in acetonitrile</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Gould, I.R.; Farid, S.</p> <p>1992-09-17</p> <p>An analysis of the <span class="hlt">dynamics</span> of the radical-ion pairs of a series of 2,6,9,10-tetracyanoanthracene acceptor/alkylbenzene donor systems in acetonitrile is described in this paper. This analysis is carried out by using a combination of time-resolved emission and absorption spectroscopies and measurements of {Phi} {sub ions} from the contact radical-ion pair (CRIP) and the solvent-separated radical-ion pair (SSRIP).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3023343','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3023343"><span id="translatedtitle">Combining Steady-State and <span class="hlt">Dynamic</span> Methods for Determining <span class="hlt">Absolute</span> Signs of Hyperfine Interactions: Pulsed ENDOR Saturation and Recovery (PESTRE)</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Doan, Peter E.</p> <p>2010-01-01</p> <p>The underlying causes of asymmetric intensities in Davies pulsed ENDOR spectra that are associated with the signs of the hyperfine interaction are reinvestigated. The intensity variations in these asymmetric ENDOR patterns are best described as shifts in an apparent baseline intensity that occurs <span class="hlt">dynamically</span> following on-resonance ENDOR transitions. We have developed an extremely straightforward multi-sequence protocol that is capable of giving the sign of the hyperfine interaction by probing a single ENDOR transition, without reference to its partner transition. This technique, Pulsed ENDOR Saturatation and Recovery (PESTRE) monitors <span class="hlt">dynamic</span> shifts in the ‘baseline’ following measurements at a single RF frequency (single ENDOR peak), rather than observing anomalous ENDOR intensity differences between the two branches of an ENDOR response. These baseline shifts, referred to as <span class="hlt">dynamic</span> reference levels (DRLs), can be directly tied to the electron spin manifold from which that ENDOR transition arises. The application of this protocol is demonstrated on 57Fe ENDOR of a 2Fe-2S ferredoxin. We use the 14N ENDOR transitions of the S = 3/2 [Fe(II)NO]2+ center of the non-heme iron enzyme, anthranilate dioxygenase (AntDO) to examine the details of the relaxation model using PESTRE. PMID:21075026</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/19253361','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/19253361"><span id="translatedtitle"><span class="hlt">Absolute</span> quantification of cerebral blood flow in neurologically normal volunteers: <span class="hlt">dynamic</span>-susceptibility contrast MRI-perfusion compared with computed tomography (CT)-perfusion.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ziegelitz, Doerthe; Starck, Göran; Mikkelsen, Irene K; Tullberg, Mats; Edsbagge, Mikael; Wikkelsö, Carsten; Forssell-Aronson, Eva; Holtås, Stig; Knutsson, Linda</p> <p>2009-07-01</p> <p>To improve the reproducibility of arterial input function (AIF) registration and <span class="hlt">absolute</span> cerebral blood flow (CBF) quantification in <span class="hlt">dynamic</span>-susceptibility MRI-perfusion (MRP) at 1.5T, we rescaled the AIF by use of a venous output function (VOF). We compared CBF estimates of 20 healthy, elderly volunteers, obtained by computed tomography (CT)-perfusion (CTP) and MRP on two consecutive days. MRP, calculated without the AIF correction, did not result in any significant correlation with CTP. The rescaled MRP showed fair to moderate correlation with CTP for the central gray matter (GM) and the whole brain. Our results indicate that the method used for correction of partial volume effects (PVEs) improves MRP experiments by reducing AIF-introduced variance at 1.5T. PMID:19253361</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=VALUE+AND+ABSOLUTE&id=EJ1000865','ERIC'); return false;" href="http://eric.ed.gov/?q=VALUE+AND+ABSOLUTE&id=EJ1000865"><span id="translatedtitle">Teaching <span class="hlt">Absolute</span> Value Meaningfully</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Wade, Angela</p> <p>2012-01-01</p> <p>What is the meaning of <span class="hlt">absolute</span> value? And why do teachers teach students how to solve <span class="hlt">absolute</span> value equations? <span class="hlt">Absolute</span> value is a concept introduced in first-year algebra and then reinforced in later courses. Various authors have suggested instructional methods for teaching <span class="hlt">absolute</span> value to high school students (Wei 2005; Stallings-Roberts…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4363941','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4363941"><span id="translatedtitle">Membrane related <span class="hlt">dynamics</span> and the formation of actin in cells growing on micro-<span class="hlt">topographies</span>: a spatial computational model</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p></p> <p>2014-01-01</p> <p> to be verified in wet-lab experiments. Conclusion Letting cells grow on surface structures is a possibility to shed new light on the intricate mechanisms that relate membrane and actin related <span class="hlt">dynamics</span> in the cell. Our results demonstrate the need for declarative expressive spatial modeling approaches that allow probing different hypotheses, and the central role of the focal adhesion complex not only for nucleating actin filaments, but also for regulating possible severing agents locally. PMID:25200251</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014SGeo...35..661J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014SGeo...35..661J"><span id="translatedtitle">Toward Improved Estimation of the <span class="hlt">Dynamic</span> <span class="hlt">Topography</span> and Ocean Circulation in the High Latitude and Arctic Ocean: The Importance of GOCE</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Johannessen, J. A.; Raj, R. P.; Nilsen, J. E. Ø.; Pripp, T.; Knudsen, P.; Counillon, F.; Stammer, D.; Bertino, L.; Andersen, O. B.; Serra, N.; Koldunov, N.</p> <p>2014-05-01</p> <p>The Arctic plays a fundamental role in the climate system and shows significant sensitivity to anthropogenic climate forcing and the ongoing climate change. Accelerated changes in the Arctic are already observed, including elevated air and ocean temperatures, declines of the summer sea ice extent and sea ice thickness influencing the albedo and CO2 exchange, melting of the Greenland Ice Sheet and increased thawing of surrounding permafrost regions. In turn, the hydrological cycle in the high latitude and Arctic is expected to undergo changes although to date it is challenging to accurately quantify this. Moreover, changes in the temperature and salinity of surface waters in the Arctic Ocean and Nordic Seas may also influence the flow of dense water through the Denmark Strait, which are found to be a precursor for changes in the Atlantic meridional overturning circulation with a lead time of around 10 years (Hawkins and Sutton in Geophys Res Lett 35:L11603, 2008). Evidently changes in the Arctic and surrounding seas have far reaching influences on regional and global environment and climate variability, thus emphasizing the need for advanced quantitative understanding of the ocean circulation and transport variability in the high latitude and Arctic Ocean. In this respect, this study combines in situ hydrographical data, surface drifter data and direct current meter measurements, with coupled sea ice-ocean models, radar altimeter data and the latest GOCE-based geoid in order to estimate and assess the quality, usefulness and validity of the new GOCE-derived mean <span class="hlt">dynamic</span> <span class="hlt">topography</span> for studies of the ocean circulation and transport estimates in the Nordic Seas and Arctic Ocean.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..1413998B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..1413998B"><span id="translatedtitle">Open<span class="hlt">Topography</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Baru, C.; Arrowsmith, R.; Crosby, C.; Nandigam, V.; Phan, M.; Cowart, C.</p> <p>2012-04-01</p> <p>Open<span class="hlt">Topography</span> is a cyberinfrastructure-based facility for online access to high-resolution <span class="hlt">topography</span> and tools. The project is an outcome of the Geosciences Network (GEON) project, which was a research project funded several years ago in the US to investigate the use of cyberinfrastructure to support research and education in the geosciences. Open<span class="hlt">Topography</span> provides online access to large LiDAR point cloud datasets along with services for processing these data. Users are able to generate custom DEMs by invoking DEM services provided by Open<span class="hlt">Topography</span> with custom parameter values. Users can track the progress of their jobs, and a private myOpenTopo area retains job information and job outputs. Data available at Open<span class="hlt">Topography</span> are provided by a variety of data acquisition groups under joint agreements and memoranda of understanding (MoU). These include national facilities such as the National Center for Airborne Lidar Mapping, as well as local, state, and federal agencies. Open<span class="hlt">Topography</span> is also being designed as a hub for high-resolution <span class="hlt">topography</span> resources. Datasets and services available at other locations can also be registered here, providing a "one-stop shop" for such information. We will describe the Open<span class="hlt">Topography</span> system architecture and its current set of features, including the service-oriented architecture, a job-tracking database, and social networking features. We will also describe several design and development activities underway to archive and publish datasets using digital object identifiers (DOIs); create a more flexible and scalable high-performance environment for processing of large datasets; extend support for satellite-based and terrestrial lidar as well as synthetic aperture radar (SAR) data; and create a "pluggable" infrastructure for third-party services. Open<span class="hlt">Topography</span> has successfully created a facility for sharing lidar data. In the next phase, we are developing a facility that will also enable equally easy and successful sharing of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://medlineplus.gov/ency/article/003649.htm','NIH-MEDLINEPLUS'); return false;" href="https://medlineplus.gov/ency/article/003649.htm"><span id="translatedtitle">Eosinophil count - <span class="hlt">absolute</span></span></a></p> <p><a target="_blank" href="http://medlineplus.gov/">MedlinePlus</a></p> <p></p> <p></p> <p>Eosinophils; <span class="hlt">Absolute</span> eosinophil count ... the white blood cell count to give the <span class="hlt">absolute</span> eosinophil count. ... than 500 cells per microliter (cells/mcL). Normal value ranges may vary slightly among different laboratories. Talk ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=inspection+AND+techniques&pg=3&id=EJ096841','ERIC'); return false;" href="http://eric.ed.gov/?q=inspection+AND+techniques&pg=3&id=EJ096841"><span id="translatedtitle">X Ray <span class="hlt">Topography</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Balchin, A. A.</p> <p>1974-01-01</p> <p>Discusses some aspects in X-ray <span class="hlt">topography</span>, 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)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001SPIE.4419...50M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001SPIE.4419...50M"><span id="translatedtitle">Moire <span class="hlt">topography</span> in odontology</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Moreno Yeras, A.</p> <p>2001-08-01</p> <p>For several decades measurement optical techniques have been used in different branches of Science and Technology and in medicine. One of these techniques is the so-called Moire <span class="hlt">topography</span> that allows the accurate measurement of different parts of the human body <span class="hlt">topography</span>. This investigation presents the measurement of <span class="hlt">topographies</span> of teeth and gums using an automated system of shadow moire, with which precision can be reached up to the order of the microns by the phase shift instrumentation in an original way. Advantages and disadvantages of using the Moire <span class="hlt">topography</span> and its comparison with other techniques used in the optical metrology are presented. Also, some positive and negative aspects of the implementation of this technique are shown in dentistry.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_8 --> <div id="page_9" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="161"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JHyd..510..124L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JHyd..510..124L"><span id="translatedtitle">Effects of <span class="hlt">topography</span> and soil depth on saturated-zone <span class="hlt">dynamics</span> in steep hillslopes explored using the three-dimensional Richards' equation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liang, Wei-Li; Uchida, Taro</p> <p>2014-03-01</p> <p>The generation of subsurface saturation has large implications for hydrological response in a catchment. Although rainfall-runoff responses have been observed worldwide in many catchments, the spatiotemporal patterns of soil-water movement and subsurface saturation processes in hillslopes and catchments are not yet fully understood because of the small number of observations and their limited areal extent. Numerical simulation allows for exploration of the entire subsurface saturation process in a hillslope or basin. In this study, as a virtual experiment we used a three-dimensional Richards' equation and detailed observational data of <span class="hlt">topography</span> and soil depth to examine the <span class="hlt">dynamics</span> of subsurface saturated-zone generation in steep hillslopes in a catchment during a storm event. Such a simulation approach had not been previously applied for a catchment-scale area. In order to identify the effects of topographic factors on saturation development, we excluded the influence of the heterogeneity of hydraulic properties and used three generalized hydraulic parameter sets that were previously proposed for environments similar to our site. The resulting waveforms of discharges in the three simulations were quite different and unexpected, which was predominately attributed to the combination of soil and bedrock hydraulic conductivity characteristics. However, common appearances in spatial and temporal variations in the generations of saturated zones were found in the three simulations. Subsurface saturation predominately developed at the soil-bedrock interface where saturated zones were generated fragmentarily and locally at first and then connected to flow downslope, flowing from the upper or middle slope areas to the lower slope area. The fragmentary development of saturated zones in the early stage during the storm event was controlled by soil depth; subsequently, the lateral transfer of saturation was controlled by the topographic wetness index at the soil</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhyA..439....1O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhyA..439....1O"><span id="translatedtitle"><span class="hlt">Absolute</span> negative mobility of interacting Brownian particles</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ou, Ya-li; Hu, Cai-tian; Wu, Jian-chun; Ai, Bao-quan</p> <p>2015-12-01</p> <p>Transport of interacting Brownian particles in a periodic potential is investigated in the presence of an ac force and a dc force. From Brownian <span class="hlt">dynamic</span> simulations, we find that both the interaction between particles and the thermal fluctuations play key roles in the <span class="hlt">absolute</span> negative mobility (the particle noisily moves backwards against a small constant bias). When no the interaction acts, there is only one region where the <span class="hlt">absolute</span> negative mobility occurs. In the presence of the interaction, the <span class="hlt">absolute</span> negative mobility may appear in multiple regions. The weak interaction can be helpful for the <span class="hlt">absolute</span> negative mobility, while the strong interaction has a destructive impact on it.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JVGR..310..172S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JVGR..310..172S"><span id="translatedtitle">The oscillation model of hydrothermal <span class="hlt">dynamics</span> beneath Aso volcano, southwest Japan after small eruption on May 2011: A new understanding model using repeated <span class="hlt">absolute</span> and relative gravity measurement</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sofyan, Yayan; Nishijima, Jun; Fujimitsu, Yasuhiro; Yoshikawa, Shin; Kagiyama, Tsuneomi; Ohkura, Takahiro</p> <p>2016-01-01</p> <p>At the end of 2010, the seismic activity in Aso volcano intensely increased and water level in the Nakadake crater decreased until early in 2011, then was followed by a small eruption in May 2011. After the eruption and heavy rain, the volcanic activity subsided to calm period, crater bottom was refilled with water, and water level increased in the Nakadake crater. The next tremor reappeared in 2014 and tracked to eruption in November 2014. This eruptive pattern and water level variation in the crater repeatedly appeared on the surface, and it should be related to the hydrothermal <span class="hlt">dynamics</span> beneath Aso volcano. We initiated the gravity measurements in relation to hydrothermal <span class="hlt">dynamics</span> in the subsurface of Aso volcano using Scintrex CG-5 (549) and LaCoste Romberg type G-1016 relative gravimeter at 28 benchmarks in April 2011, one month before the eruption. The repeated gravity measurements continue to monitor Aso volcano with a series of the measurement after the eruption in every three months to a half year. We analyze the gravity variation from 2011 to 2014 between the time of the phreatic and strombolian eruption. The measurements covered the area more than 60 km2 in the west side of Aso caldera. A new gravity network was also installed in May 2010 at seven benchmarks using A10-017 <span class="hlt">absolute</span> gravimeter, which re-occupied in October 2010, June 2011 and two benchmarks in June 2014. As a result, the gravity changes distinguish hydrothermal <span class="hlt">dynamic</span> in the subsurface, which has a direct correlation to water level fluctuation in the crater, after the first eruption and before the second discharge. The monitoring data notice large gravity changes between the surveys at benchmarks around Nakadake crater and Kusasenri area. The simple 3D inversion models of the 4-D gravity data deduce the density contrast distribution beneath Aso volcano. The inversion and mass change result generate the oscillation typical as a new understanding model. The variation of the mass shows a</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1042637','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1042637"><span id="translatedtitle"><span class="hlt">Absolute</span> nuclear material assay</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Prasad, Manoj K.; Snyderman, Neal J.; Rowland, Mark S.</p> <p>2012-05-15</p> <p>A method of <span class="hlt">absolute</span> nuclear material assay of an unknown source comprising counting neutrons from the unknown source and providing an <span class="hlt">absolute</span> nuclear material assay utilizing a model to optimally compare to the measured count distributions. In one embodiment, the step of providing an <span class="hlt">absolute</span> nuclear material assay comprises utilizing a random sampling of analytically computed fission chain distributions to generate a continuous time-evolving sequence of event-counts by spreading the fission chain distribution in time.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/993087','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/993087"><span id="translatedtitle"><span class="hlt">Absolute</span> nuclear material assay</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Prasad, Manoj K.; Snyderman, Neal J.; Rowland, Mark S.</p> <p>2010-07-13</p> <p>A method of <span class="hlt">absolute</span> nuclear material assay of an unknown source comprising counting neutrons from the unknown source and providing an <span class="hlt">absolute</span> nuclear material assay utilizing a model to optimally compare to the measured count distributions. In one embodiment, the step of providing an <span class="hlt">absolute</span> nuclear material assay comprises utilizing a random sampling of analytically computed fission chain distributions to generate a continuous time-evolving sequence of event-counts by spreading the fission chain distribution in time.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..1714981I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..1714981I"><span id="translatedtitle">Post-fire Vegetation Regeneration <span class="hlt">Dynamics</span> to <span class="hlt">Topography</span> and Burn Severity in two contrasting ecosystems: the Case of the Montane Cordillera Ecozones of Western Canada & that of a Typical Mediterranean site in Greece</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ireland, Gareth; Petropoulos, George P.; Kalivas, Dionissios; Griffirths, Hywel M.; Louka, Panagiota</p> <p>2015-04-01</p> <p>Altering land cover <span class="hlt">dynamics</span> is currently regarded as the single most important variable of global change affecting ecological systems. Wildfires are an integral part of many terrestrial ecosystems and are considered to dramatically affect land cover <span class="hlt">dynamics</span> at a variety of spatial and temporal scales. In this context, knowledge of the spatio-temporal distribution of post-fire vegetation recovery <span class="hlt">dynamics</span> is of key importance. In this study, we explore the relationships between vegetation recovery <span class="hlt">dynamics</span> to <span class="hlt">topography</span> and burn severity for two different ecosystems using a chronosequence of Landsat TM data images analysis. One of our experimental sites is the Okanagan Mountain Park, located in the Montane Cordillera Ecozones of western Canada at which a fire occurred in 2003. The other is Mt. Parnitha, located in Greece, representing a typical Mediterranean setting. The spatio-temporal patterns of regrowth for 8 years following the fire events were quantified based on the analysis of 2 widely used indices, the Normalized Difference Vegetation Index (NDVI) and the Regeneration Index (RI). Burn severity was derived from the differenced Normalized Burn Ratio (dNBR) index computed from the Landsat TM images. Topographical information for the studied area was obtained from the ASTER global operational product. Relationships of vegetation regrowth to both <span class="hlt">topography</span> and burn severity was quantified using a series of additional statistical metrics. In overall, results indicated noticeable differences in the recovery rates of both ecosystems to the pre-fire patterns. Re-growth rates appeared to be somewhat higher in north-facing slopes in comparison to south facing ones for both experimental sites, in common with other similar studies in different ecosystems. Lastly, areas of lower burn severity exhibited a higher recovery rate compared to areas of high severity burns. Results are presented in detail and an explanation of the main observation trends is also attempted to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015NPGeo..22..713L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015NPGeo..22..713L"><span id="translatedtitle">Universal multifractal Martian <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Landais, F.; Schmidt, F.; Lovejoy, S.</p> <p>2015-11-01</p> <p>In the present study, we investigate the scaling properties of the <span class="hlt">topography</span> of Mars. Planetary topographic fields are well known to roughly exhibit (mono)fractal behavior. Indeed, the fractal formalism reproduces much of the variability observed in <span class="hlt">topography</span>. Still, a single fractal dimension is not enough to explain the huge variability and intermittency. Previous studies have claimed that fractal dimensions might be different from one region to another, excluding a general description at the planetary scale. In this article, we analyze the Martian topographic data with a multifractal formalism to study the scaling intermittency. In the multifractal paradigm, the apparent local variation of the fractal dimension is interpreted as a statistical property of multifractal fields. We analyze the <span class="hlt">topography</span> measured with the Mars Orbiter Laser altimeter (MOLA) at 300 m horizontal resolution, 1 m vertical resolution. We adapted the Haar fluctuation method to the irregularly sampled signal. The results suggest a multifractal behavior from the planetary scale down to 10 km. From 10 to 300 m, the <span class="hlt">topography</span> seems to be simple monofractal. This transition indicates a significant change in the geological processes governing the Red Planet's surface.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015NPGD....2.1007L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015NPGD....2.1007L"><span id="translatedtitle">Universal multifractal Martian <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Landais, F.; Schmidt, F.; Lovejoy, S.</p> <p>2015-07-01</p> <p>In the present study, we investigate the scaling properties of the <span class="hlt">topography</span> of Mars. Planetary topographic fields are well known to roughly exhibit (mono)fractal behavior. Indeed, the fractal formalism is reproduces much of the variability observed in <span class="hlt">topography</span>. Still, a single fractal dimension is not enough to explain the huge variability and intermittency. Previous studies have claimed that fractal dimensions might be different from one region to an other, excluding a general description at the planetary scale. In this article, we are analyzing the Martian topographic data with a multifractal formalism to study the scaling intermittency. In the multifractal paradigm, the apparent local variation of the fractal dimension is interpreted as a statistical property of multifractal fields. We analyze the <span class="hlt">topography</span> measured with the laser altimeter MOLA at 300 m horizontal resolution, 1 m vertical resolution. We adapted the Haar fluctuation method to the the irregularly sampled signal. The results suggest a multifractal behavior from planetary scale down to 10 km. From 10 km to 300 m, the <span class="hlt">topography</span> seems to be simple monofractal. This transition indicates a significant change in the geological processes governing the Red Planet's surface.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014P%26SS..102...51W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014P%26SS..102...51W"><span id="translatedtitle">Phobos' shape and <span class="hlt">topography</span> models</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Willner, K.; Shi, X.; Oberst, J.</p> <p>2014-11-01</p> <p>The global shape and the <span class="hlt">dynamic</span> environment are fundamental properties of a body. Other properties such as volume, bulk density, and models for the <span class="hlt">dynamic</span> environment can subsequently be computed based on such models. Stereo-photogrammetric methods were applied to derive a global digital terrain model (DTM) with 100 m/pixel resolution using High Resolution Stereo Camera images of the Mars Express mission and Viking Orbiter images. In a subsequent least-squares fit, coefficients of the spherical harmonic function to degree and order 45 are computed. The <span class="hlt">dynamic</span> models for Phobos were derived from a polyhedron representation of the DTM. The DTM, spherical harmonic function model, and <span class="hlt">dynamic</span> models, have been refined and represent Phobos' <span class="hlt">dynamic</span> and geometric <span class="hlt">topography</span> with much more detail when compared to Shi et al. (2012) and Willner et al. (2010) models, respectively. The volume of Phobos has been re-determined to be in the order of 5741 km3 with an uncertainty of only 0.6% of the total volume. This reduces the bulk density to 1.86±0.013 g/cm3 in comparison to previous results. Assuming a homogeneous mass distribution a forced libration amplitude for Phobos of 1.14° is computed that is in better agreement with observations by Willner et al. (2010) than previous estimates.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19780061113&hterms=ferrari&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dferrari','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19780061113&hterms=ferrari&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dferrari"><span id="translatedtitle">Mars <span class="hlt">topography</span> harmonics and geophysical implications</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bills, B. G.; Ferrari, A. J.</p> <p>1978-01-01</p> <p>The paper describes an improved model of Martian global <span class="hlt">topography</span> which has been obtained by fitting a sixteenth-degree harmonic series to occultation, radar, spectral, and photogrammetric measurements. Empirical elevation data based on photographic data are used to supplement the observations in areas without data. Values for the mean radius, the mean density, and the displacement of the center of the figure from the center of mass are presented. The reported geometric flattening is too great and the reported <span class="hlt">dynamic</span> flattening is too small for Mars to be homogeneous and hydrostatic. Maps of the data distribution, global <span class="hlt">topography</span>, and Bouguer gravity anomaly are interpreted in terms of a crustal thickness map which is consistent with gravity, <span class="hlt">topography</span>, and recent preliminary Viking seismic results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140010845','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140010845"><span id="translatedtitle">The Dawn <span class="hlt">Topography</span> Investigation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Raymond, C. A.; Jaumann, R.; Nathues, A.; Sierks, H.; Roatsch, T.; Preusker, E; Scholten, F.; Gaskell, R. W.; Jorda, L.; Keller, H.-U.; Zuber, M. T.; Smith, D. E.; Mastrodemos, N.; Mottola, S.</p> <p>2011-01-01</p> <p>The objective of the Dawn <span class="hlt">topography</span> 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 <span class="hlt">topography</span> 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 <span class="hlt">topography</span> will likely reveal much about processes of surface modification as well as the internal structure and evolution of this dwarf planet.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23586876','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23586876"><span id="translatedtitle"><span class="hlt">Absolute</span> biological needs.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>McLeod, Stephen</p> <p>2014-07-01</p> <p><span class="hlt">Absolute</span> needs (as against instrumental needs) are independent of the ends, goals and purposes of personal agents. Against the view that the only needs are instrumental needs, David Wiggins and Garrett Thomson have defended <span class="hlt">absolute</span> needs on the grounds that the verb 'need' has instrumental and <span class="hlt">absolute</span> senses. While remaining neutral about it, this article does not adopt that approach. Instead, it suggests that there are <span class="hlt">absolute</span> biological needs. The <span class="hlt">absolute</span> nature of these needs is defended by appeal to: their objectivity (as against mind-dependence); the universality of the phenomenon of needing across the plant and animal kingdoms; the impossibility that biological needs depend wholly upon the exercise of the abilities characteristic of personal agency; the contention that the possession of biological needs is prior to the possession of the abilities characteristic of personal agency. Finally, three philosophical usages of 'normative' are distinguished. On two of these, to describe a phenomenon or claim as 'normative' is to describe it as value-dependent. A description of a phenomenon or claim as 'normative' in the third sense does not entail such value-dependency, though it leaves open the possibility that value depends upon the phenomenon or upon the truth of the claim. It is argued that while survival needs (or claims about them) may well be normative in this third sense, they are normative in neither of the first two. Thus, the idea of <span class="hlt">absolute</span> need is not inherently normative in either of the first two senses. PMID:23586876</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009ECSS...85..593K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009ECSS...85..593K"><span id="translatedtitle">Exploring LiDAR data for mapping the micro-<span class="hlt">topography</span> and tidal hydro-<span class="hlt">dynamics</span> of mangrove systems: An example from southeast Queensland, Australia</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Knight, Jon M.; Dale, Pat E. R.; Spencer, John; Griffin, Lachlan</p> <p>2009-12-01</p> <p>The aim was to explore the use of Light Detection and Ranging (LiDAR) data to map the micro-<span class="hlt">topography</span> of an intertidal wetland in southeast Queensland Australia. The driver for this was the need to identify and map the habitats of the immature stages of an aedine disease vector mosquito ( Aedes vigilax (Skuse)). We derived a high resolution digital elevation model (DEM) data set at a vertical resolution of 0.05 m from LiDAR data. The relative accuracy of the DEM across the site was tested by comparing water depth predictions derived from the DEM against in-situ water depth readings from pressure sensors over a 10-day tidal cycle, which included high spring tides. We found that the field observations of micro-topographic units important for mosquito management matched those delineated from the DEM. The micro-<span class="hlt">topography</span> included a low berm or central ridge that was more or less continuous across the site, a shallow back basin and fringing mangroves. The fringing mangroves had unimpeded connection to the tidal source, however the central ridge blocked tidal water from the back basin for all but the highest tides. Eggshell survey indicated that the back basin was the area suitable for immature mosquitoes. We conclude that LiDAR data has application for understanding and mapping the structure of mangrove wetlands. We have also demonstrated (in a small area) that LiDAR is useful for modelling the effect of sea level changes on the coastal fringe. LiDAR may be the only method to inform research on changes to land use and ecosystems caused by sea level change.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012PhDT.......187S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012PhDT.......187S"><span id="translatedtitle">Investigations of Titan's <span class="hlt">topography</span> and surface roughness</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sharma, Priyanka</p> <p></p> <p>Saturn's moon, Titan is a geomorphologically active planetary object, and its surface is influenced by multiple processes like impact cratering, fluvial and aeolian erosion, lacustrine processes, tectonics, cryovolcanism and mantling. Disentangling the processes that compete to shape Titan's landscape is difficult in the absence of global <span class="hlt">topography</span> data. In this thesis, I utilize techniques in topographic statistics, fractal theory, study of terrestrial analogs and landscape evolution modeling to characterize Titan's <span class="hlt">topography</span> and surface roughness and investigate the relative roles of surface processes in sculpting its landscape. I mapped the shorelines of 290 North Polar Titanian lakes using the Cassini Synthetic Aperture Radar dataset. The fractal dimensions of the shorelines were calculated via the divider/ruler method and box-counting method, at length scales of (1--10) km and found to average 1.27 and 1.32, respectively. The inferred power-spectral exponent of Titan's <span class="hlt">topography</span> was found to be ≤ 2, which is lower than the values obtained from the global <span class="hlt">topography</span> of the Earth or Venus. In order to interpret fractal dimensions of Titan's shorelines in terms of the surficial processes at work, I repeated a similar statistical analysis with 114 terrestrial analogous lakes formed by different processes, using C-band radar backscatter data from the Shuttle Radar <span class="hlt">Topography</span> Mission (SRTM). I found different lake generation mechanisms on Earth produce 'statistically different' shorelines; however, no specific set of processes could be identified for forming Titanian lake basins. Using the Cassini RADAR altimetry data, I investigated Titan's global surface roughness and calculated median <span class="hlt">absolute</span> slopes, average relief and Hurst exponent (H) for the surface of Titan. I detected a clear trend with latitude in these roughness parameters. Equatorial regions had the smallest slopes, lowest values of H and smallest intra-footprint relief, compared to the mid</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012SPIE.8209E..1US','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012SPIE.8209E..1US"><span id="translatedtitle">Toward optical coherence <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sayegh, Samir; Jiang, Yanshui</p> <p>2012-03-01</p> <p>Commercial OCT systems provide pachymetry measurements. Full corneal topographic information of anterior and posterior corneal surfaces for use in cataract surgery and refractive procedures is a desirable goal and would add to the usefulness of anterior and posterior segment evaluation. While substantial progress has been made towards obtaining "average" central corneal power (D Huang), power in different meridians and <span class="hlt">topography</span> are still missing. This is usually reported to be due to eye movement. We analyze the role of centration, eye movements and develop a model that allows for the formulation of criteria for obtaining reliable topographic data within ¼ diopter.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1231575-absolute-path-command','SCIGOV-ESTSC'); return false;" href="http://www.osti.gov/scitech/biblio/1231575-absolute-path-command"><span id="translatedtitle">The <span class="hlt">absolute</span> path command</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech/">Energy Science and Technology Software Center (ESTSC)</a></p> <p></p> <p>2012-05-11</p> <p>The ap command traveres all symlinks in a given file, directory, or executable name to identify the final <span class="hlt">absolute</span> path. It can print just the final path, each intermediate link along with the symlink chan, and the permissions and ownership of each directory component in the final path. It has functionality similar to "which", except that it shows the final path instead of the first path. It is also similar to "pwd", but it canmore » provide the <span class="hlt">absolute</span> path to a relative directory from the current working directory.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1231575','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1231575"><span id="translatedtitle">The <span class="hlt">absolute</span> path command</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Moody, A.</p> <p>2012-05-11</p> <p>The ap command traveres all symlinks in a given file, directory, or executable name to identify the final <span class="hlt">absolute</span> path. It can print just the final path, each intermediate link along with the symlink chan, and the permissions and ownership of each directory component in the final path. It has functionality similar to "which", except that it shows the final path instead of the first path. It is also similar to "pwd", but it can provide the <span class="hlt">absolute</span> path to a relative directory from the current working directory.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4315668','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4315668"><span id="translatedtitle"><span class="hlt">Absolute</span> Quantitation of Myocardial Blood Flow in Human Subjects with or without Myocardial Ischemia using <span class="hlt">Dynamic</span> Flurpiridaz F 18 Positron Emission Tomography</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Packard, René R. S.; Huang, Sung-Cheng; Dahlbom, Magnus; Czernin, Johannes; Maddahi, Jamshid</p> <p>2015-01-01</p> <p><span class="hlt">Absolute</span> quantitation of myocardial blood flow (MBF) by positron emission tomography (PET) is an established method of analyzing coronary artery disease (CAD) but subject to the various shortcomings of available radiotracers. Flurpiridaz F 18 is a novel PET radiotracer which exhibits properties of an ideal tracer. Methods A new <span class="hlt">absolute</span> perfusion quantitation method with Flurpiridaz was developed, taking advantage of the early kinetics and high first-pass extraction by the myocardium of this radiotracer, and the first in human measurements of MBF performed in 7 normal subjects and 8 patients with documented CAD. PET images with time-activity curves were acquired at rest and during adenosine stress. Results In normal subjects, regional MBF between coronary artery territories did not differ significantly, leading to a mean global MBF of 0.73 mL/min/g at rest and 2.53 mL/min/g during stress, with a mean global myocardial flow reserve (MFR) of 3.70. CAD vascular territories with <50% stenosis demonstrated a mean MBF of 0.73 at rest and 2.02 during stress, leading to a mean MFR of 2.97. CAD vascular territories with ≥50% stenosis exhibited a mean MBF of 0.86 at rest and 1.43 during stress, leading to a mean MFR of 1.86. Differences in stress MBF and MFR between normal and CAD territories, as well as between <50% and ≥50% stenosis vascular territories, were significant (P<0.01). Conclusion <span class="hlt">Absolute</span> quantitation of MBF in humans with the novel PET radiotracer Flurpiridaz is feasible over a wide range of cardiac flow in the presence or absence of stress-inducible myocardial ischemia. The significant decrease in stress MBF and ensuing MFR in CAD territories allows a clear distinction between vascular territories exhibiting stress-inducible myocardial ischemia and those with normal perfusion. PMID:25071096</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20000110271&hterms=MOLA&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DMOLA','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20000110271&hterms=MOLA&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DMOLA"><span id="translatedtitle">Implications of MOLA Global Roughness, Statistics, and <span class="hlt">Topography</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Aharonson, O.; Zuber, M. T.; Neumann, G. A.</p> <p>1999-01-01</p> <p>New insights are emerging as the ongoing high-quality measurements of the Martian surface <span class="hlt">topography</span> by Mars Orbiter Laser Altimeter (MOLA) on board the Mars Global Surveyor (MGS) spacecraft increase in coverage, resolution, and diversity. For the first time, a global characterization of the statistical properties of <span class="hlt">topography</span> is possible. The data were collected during the aerobreaking hiatus, science phasing, and mapping orbits of MGS, and have a resolution of 300-400 m along track, a range resolution of 37.5 cm, a range precision of 1-10 m for surface slopes up to 30 deg., and an <span class="hlt">absolute</span> accuracy of <span class="hlt">topography</span> of 13 m. The spacecraft's orbit inclination dictates that nadir observations have latitude coverage of about 87.1S to 87.1N; the addition of observations obtained during a period of off-nadir pointing over the north pole extended coverage to 90N. Additional information is contained in the original extended abstract.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20050170605','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20050170605"><span id="translatedtitle">RADAR Reveals Titan <span class="hlt">Topography</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kirk, R. L.; Callahan, P.; Seu, R.; Lorenz, R. D.; Paganelli, F.; Lopes, R.; Elachi, C.</p> <p>2005-01-01</p> <p>The Cassini Titan RADAR Mapper is a K(sub u)-band (13.78 GHz, lambda = 2.17 cm) linear polarized RADAR instrument capable of operating in synthetic aperture (SAR), scatterometer, altimeter and radiometer modes. During the first targeted flyby of Titan on 26 October, 2004 (referred to as Ta) observations were made in all modes. Evidence for topographic relief based on the Ta altimetry and SAR data are presented here. Additional SAR and altimetry observations are planned for the T3 encounter on 15 February, 2005, but have not been carried out at this writing. Results from the T3 encounter relevant to <span class="hlt">topography</span> will be included in our presentation. Data obtained in the Ta encounter include a SAR image swath</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_9 --> <div id="page_10" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="181"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=PIA00740&hterms=Dark+web&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DDark%2Bweb','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=PIA00740&hterms=Dark+web&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DDark%2Bweb"><span id="translatedtitle"><span class="hlt">Topography</span> of Io (color)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1997-01-01</p> <p>The images used to create this color composite of Io were acquired by Galileo during its ninth orbit (C9) of Jupiter and are part of a sequence of images designed to map the <span class="hlt">topography</span> or relief on Io and to monitor changes in the surface color due to volcanic activity. Obtaining images at low illumination angles is like taking a picture from a high altitude around sunrise or sunset. Such lighting conditions emphasize the <span class="hlt">topography</span> of the volcanic satellite. Several mountains up to a few miles high can be seen in this view, especially near the upper right. Some of these mountains appear to be tilted crustal blocks. Most of the dark spots correspond to active volcanic centers.<p/>North is to the top of the picture which merges images obtained with the clear, red, green, and violet filters of the solid state imaging (CCD) system on NASA's Galileo spacecraft. . The resolution is 8.3 kilometers per picture element. The image was taken on June 27, 1997 at a range of 817,000 kilometers by the solid state imaging (CCD) system on NASA's Galileo spacecraft.<p/>The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).<p/>This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4028274','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4028274"><span id="translatedtitle">Lake <span class="hlt">Topography</span> and Wind Waves Determining Seasonal-Spatial <span class="hlt">Dynamics</span> of Total Suspended Matter in Turbid Lake Taihu, China: Assessment Using Long-Term High-Resolution MERIS Data</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Zhang, Yunlin; Shi, Kun; Liu, Xiaohan; Zhou, Yongqiang; Qin, Boqiang</p> <p>2014-01-01</p> <p>Multiple comprehensive in situ bio-optical investigations were conducted from 2005 to 2010 and covered a large variability of total suspended matter (TSM) in Lake Taihu to calibrate and validate a TSM concentration estimation model based on Medium Resolution Imaging Spectrometer (MERIS) data. The estimation model of the TSM concentration in Lake Taihu was developed using top-of-atmosphere (TOA) radiance of MERIS image data at band 9 in combination with a regional empirical atmospheric correction model, which was strongly correlated with the in situ TSM concentration (r2 = 0.720, p<0.001, and n = 73). The relative root mean square error (RRMSE) and mean relative error (MRE) were 36.9% and 31.6%, respectively, based on an independent validation dataset that produced reliable estimations of the TSM concentration. The developed algorithm was applied to 50 MERIS images from 2003 to 2011 to obtain a high spatial and temporal heterogeneity of TSM concentrations in Lake Taihu. Seasonally, the highest and lowest TSM concentrations were found in spring and autumn, respectively. Spatially, TSM concentrations were high in the southern part and center of the lake and low in Xukou Bay, East Lake Taihu. The lake <span class="hlt">topography</span>, including the water depth and distance from the shore, had a significant effect on the TSM spatial distribution. A significant correlation was found between the daily average wind speed and TSM concentration (r2 = 0.685, p<0.001, and n = 50), suggesting a critical role of wind speed in the TSM variations in Lake Taihu. In addition, a low TSM concentration was linked to the appearance of submerged aquatic vegetation (SAV). Therefore, TSM <span class="hlt">dynamics</span> were controlled by the lake <span class="hlt">topography</span>, wind-driven sediment resuspension and SAV distribution. PMID:24846206</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26022836','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26022836"><span id="translatedtitle"><span class="hlt">Absolutely</span> relative or relatively <span class="hlt">absolute</span>: violations of value invariance in human decision making.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Teodorescu, Andrei R; Moran, Rani; Usher, Marius</p> <p>2016-02-01</p> <p>Making decisions based on relative rather than <span class="hlt">absolute</span> information processing is tied to choice optimality via the accumulation of evidence differences and to canonical neural processing via accumulation of evidence ratios. These theoretical frameworks predict invariance of decision latencies to <span class="hlt">absolute</span> intensities that maintain differences and ratios, respectively. While information about the <span class="hlt">absolute</span> values of the choice alternatives is not necessary for choosing the best alternative, it may nevertheless hold valuable information about the context of the decision. To test the sensitivity of human decision making to <span class="hlt">absolute</span> values, we manipulated the intensities of brightness stimuli pairs while preserving either their differences or their ratios. Although asked to choose the brighter alternative relative to the other, participants responded faster to higher <span class="hlt">absolute</span> values. Thus, our results provide empirical evidence for human sensitivity to task irrelevant <span class="hlt">absolute</span> values indicating a hard-wired mechanism that precedes executive control. Computational investigations of several modelling architectures reveal two alternative accounts for this phenomenon, which combine <span class="hlt">absolute</span> and relative processing. One account involves accumulation of differences with activation dependent processing noise and the other emerges from accumulation of <span class="hlt">absolute</span> values subject to the temporal <span class="hlt">dynamics</span> of lateral inhibition. The potential adaptive role of such choice mechanisms is discussed. PMID:26022836</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015JGRE..120..287J&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015JGRE..120..287J&link_type=ABSTRACT"><span id="translatedtitle">Support of long-wavelength <span class="hlt">topography</span> on Mercury inferred from MESSENGER measurements of gravity and <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>James, Peter B.; Zuber, Maria T.; Phillips, Roger J.; Solomon, Sean C.</p> <p>2015-02-01</p> <p>To explore the mechanisms of support of surface <span class="hlt">topography</span> on Mercury, we have determined the admittances and correlations of <span class="hlt">topography</span> and gravity in Mercury's northern hemisphere from measurements obtained by NASA's MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft. These admittances and correlations can be interpreted in the context of a number of theoretical scenarios, including flexural loading and <span class="hlt">dynamic</span> flow. We find that long-wavelength (spherical harmonic degree l < 15) surface <span class="hlt">topography</span> on Mercury is primarily supported through a combination of crustal thickness variations and deep mass anomalies. The deep mass anomalies may be interpreted either as lateral variations in mantle density or as relief on compositional interfaces. Domical topographic swells are associated with high admittances and are compensated at 300-400 km depth in the lower reaches of Mercury's mantle. Quasi-linear topographic rises are primarily associated with shallow crustal compensation and are weakly correlated with positive mass anomalies in the mantle. The center of the Caloris basin features some of the thinnest crust on the planet, and the basin is underlain by a large negative mass anomaly. We also explore models of <span class="hlt">dynamic</span> flow in the presence of compositional stratification above the liquid core. If there is substantial compositional stratification in Mercury's solid outer shell, relaxation of perturbed compositional interfaces may be capable of creating and sustaining long-wavelength <span class="hlt">topography</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=PIA01217&hterms=solid+state+lighting&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dsolid%2Bstate%2Blighting','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=PIA01217&hterms=solid+state+lighting&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dsolid%2Bstate%2Blighting"><span id="translatedtitle"><span class="hlt">Topography</span> of Io</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1997-01-01</p> <p>This image of Io was acquired by Galileo during its ninth orbit (C9) of Jupiter as part of a sequence of images designed to cover Io at low illumination angles to map the landforms. Obtaining images at such illuminations is like taking a picture from a high altitude around sunrise or sunset. Such lighting conditions emphasize the <span class="hlt">topography</span> of the volcanic satellite. Several mountains up to a few miles high can be seen in this view, especially near the upper right. Some of these mountains appear to be tilted crustal blocks.<p/>North is to the top of the picture. The resolution is 8.3 kilometers per picture element. The image was taken on June 27, 1997 at a range of 817,000 kilometers by the solid state imaging (CCD) system on NASA's Galileo spacecraft.<p/>The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.<p/>This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110013051','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110013051"><span id="translatedtitle">Electronic <span class="hlt">Absolute</span> Cartesian Autocollimator</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Leviton, Douglas B.</p> <p>2006-01-01</p> <p>An electronic <span class="hlt">absolute</span> Cartesian autocollimator performs the same basic optical function as does a conventional all-optical or a conventional electronic autocollimator but differs in the nature of its optical target and the manner in which the position of the image of the target is measured. The term <span class="hlt">absolute</span> in the name of this apparatus reflects the nature of the position measurement, which, unlike in a conventional electronic autocollimator, is based <span class="hlt">absolutely</span> on the position of the image rather than on an assumed proportionality between the position and the levels of processed analog electronic signals. The term Cartesian in the name of this apparatus reflects the nature of its optical target. Figure 1 depicts the electronic functional blocks of an electronic <span class="hlt">absolute</span> Cartesian autocollimator along with its basic optical layout, which is the same as that of a conventional autocollimator. Referring first to the optical layout and functions only, this or any autocollimator is used to measure the compound angular deviation of a flat datum mirror with respect to the optical axis of the autocollimator itself. The optical components include an illuminated target, a beam splitter, an objective or collimating lens, and a viewer or detector (described in more detail below) at a viewing plane. The target and the viewing planes are focal planes of the lens. Target light reflected by the datum mirror is imaged on the viewing plane at unit magnification by the collimating lens. If the normal to the datum mirror is parallel to the optical axis of the autocollimator, then the target image is centered on the viewing plane. Any angular deviation of the normal from the optical axis manifests itself as a lateral displacement of the target image from the center. The magnitude of the displacement is proportional to the focal length and to the magnitude (assumed to be small) of the angular deviation. The direction of the displacement is perpendicular to the axis about which the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950048057&hterms=schlumberger&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dschlumberger','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950048057&hterms=schlumberger&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dschlumberger"><span id="translatedtitle">The length-scaling properties of <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Weissel, Jeffrey K.; Pratson, Lincoln F.; Malinverno, Alberto</p> <p>1994-01-01</p> <p>The scaling properties of synthetic topographic surfaces and digital elevation models (DEMs) of <span class="hlt">topography</span> are examined by analyzing their 'structure functions,' i.e., the qth order powers of the <span class="hlt">absolute</span> elevation differences: delta h(sub q) (l) = E((<span class="hlt">absolute</span> value of h(x + l) - h(x))(exp q)). We find that the relation delta h(sub 1 l) approximately equal cl(exp H) describes well the scaling behavior of natural topographic surfaces, as represented by DEMs gridded at 3 arc sec. Average values of the scaling exponent H between approximately 0.5 and 0.7 characterize DEMs from Ethiopia, Saudi Arabia, and Somalia over 3 orders of magnitude range in length scale l (approximately 0.1-150 km). Differences in appparent topographic roughness among the three areas most likely reflect differences in the amplitude factor c. Separate determination of scaling properties in the x and y coordinate directions allows us to assess whether scaling exponents are azimuthally dependent (anisotropic) or whether they are isotropic while the surface itself is anisotropic over a restricted range of length scale. We explore ways to determine whether topographic surfaces are characterized by simple or multiscaling properties.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/921934','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/921934"><span id="translatedtitle"><span class="hlt">ABSOLUTE</span> POLARIMETRY AT RHIC.</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>OKADA; BRAVAR, A.; BUNCE, G.; GILL, R.; HUANG, H.; MAKDISI, Y.; NASS, A.; WOOD, J.; ZELENSKI, Z.; ET AL.</p> <p>2007-09-10</p> <p>Precise and <span class="hlt">absolute</span> beam polarization measurements are critical for the RHIC spin physics program. Because all experimental spin-dependent results are normalized by beam polarization, the normalization uncertainty contributes directly to final physics uncertainties. We aimed to perform the beam polarization measurement to an accuracy Of {Delta}P{sub beam}/P{sub beam} < 5%. The <span class="hlt">absolute</span> polarimeter consists of Polarized Atomic Hydrogen Gas Jet Target and left-right pairs of silicon strip detectors and was installed in the RHIC-ring in 2004. This system features proton-proton elastic scattering in the Coulomb nuclear interference (CNI) region. Precise measurements of the analyzing power A{sub N} of this process has allowed us to achieve {Delta}P{sub beam}/P{sub beam} = 4.2% in 2005 for the first long spin-physics run. In this report, we describe the entire set up and performance of the system. The procedure of beam polarization measurement and analysis results from 2004-2005 are described. Physics topics of AN in the CNI region (four-momentum transfer squared 0.001 < -t < 0.032 (GeV/c){sup 2}) are also discussed. We point out the current issues and expected optimum accuracy in 2006 and the future.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3579786','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3579786"><span id="translatedtitle">Comparison of Sum <span class="hlt">Absolute</span> QRST Integral, and Temporal Variability in Depolarization and Repolarization, Measured by <span class="hlt">Dynamic</span> Vectorcardiography Approach, in Healthy Men and Women</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Tereshchenko, Larisa G.</p> <p>2013-01-01</p> <p>Background Recently we showed the predictive value of sum <span class="hlt">absolute</span> QRST integral (SAI QRST) and repolarization lability for risk stratification of sudden cardiac death (SCD) in heart failure patients. The goal of this study was to compare SAI QRST and metrics of depolarization and repolarization variability in healthy men and women. Methods Orthogonal ECGs were recorded at rest for 10 minutes in 160 healthy men and women (mean age 39.6±14.6, 80 men). Mean spatial TT′ angle, and normalized variances of T loop area, of spatial T vector amplitude, of QT interval and Tpeak-Tend area were measured for assessment of repolarization lability. Normalized variances of spatial QRS vector and QRS loop area characterized variability of depolarization. In addition, variability indices (VI) were calculated to adjust for normalized heart rate variance. SAI QRST was measured as the averaged arithmetic sum of areas under the QRST curve. Results Men were characterized by shorter QTc (430.3±21.7 vs. 444.7±22.2 ms; P<0.0001) and larger SAI QRST (282.1±66.7 vs.204.9±58.5 mV*ms; P<0.0001). Repolarization lability negatively correlated with spatial T vector amplitude. Adjusted by normalized heart rate variance, QT variability index was significantly higher in women than in men (−1.54±0.38 vs. −1.70±0.33; P = 0.017). However, in multivariate logistic regression after adjustment for body surface area, QTc, and spatial T vector amplitude, healthy men had 1.5–3 fold higher probability of having larger repolarization lability, as compared to healthy women (T vector amplitude variability index odds ratio 3.88(95%CI 1.4–11.1; P = 0.012). Conclusions Healthy men more likely than women have larger repolarization lability. PMID:23451181</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1992JChPh..96..339T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1992JChPh..96..339T"><span id="translatedtitle">Reaction <span class="hlt">dynamics</span> of D+H2 --> DH+H: Effects of potential energy surface <span class="hlt">topography</span> and usefulness of the constant centrifugal potential approximation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Takada, Shoji; Ohsaki, Akihiko; Nakamura, Hiroki</p> <p>1992-01-01</p> <p>Two findings are reported for the D+H2→DH+H reaction on the basis of the exact quantum mechanical calculation for J=0, where J is total angular momentum. First, with use of the Liu-Siegbahn-Truhlar-Horowitz (LSTH) surface and the Varandas surface, we demonstrate that a rather small difference in potential energy surface (PES) induces a surprisingly large effect on reaction <span class="hlt">dynamics</span>. Two origins of the discrepancy are pointed out and analyzed: (1) Noncollinear conformation in the reaction zone contributes to the reaction significantly despite the fact that the minimum energy path and the saddle point are located in the collinear configuration. (2) A difference in the distant part of PES also causes a discrepancy in the reaction <span class="hlt">dynamics</span> indirectly, although this effect is much smaller than (1). Secondly, we investigate the validity of the constant centrifugal potential approximation (CCPA) based on the accurate results for J=0. The use of CCPA to estimate total cross section and rate constant is again proved to have practical utility as in the cases of the sudden and adiabatic approximations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19940007593&hterms=analysis+variance&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Danalysis%2Bvariance','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19940007593&hterms=analysis+variance&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Danalysis%2Bvariance"><span id="translatedtitle">Spectral analysis of the gravity and <span class="hlt">topography</span> of Mars</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bills, Bruce G.; Frey, Herbert V.; Kiefer, Walter S.; Nerem, R. Steven; Zuber, Maria T.</p> <p>1993-01-01</p> <p>New spherical harmonic models of the gravity and <span class="hlt">topography</span> of Mars place important constraints on the structure and <span class="hlt">dynamics</span> of the interior. The gravity and <span class="hlt">topography</span> 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 change in behavior of the planet. The gravity/<span class="hlt">topography</span> admittance reveals two very different spectral domains: for n greater than 4, a simple Airy compensation model, with mean depth of 100 km, faithfully represents the observed pattern; for degrees 2 and 3, the effective compensation depths are 1400 and 550 km, respectively, strongly arguing for <span class="hlt">dynamic</span> compensation at those wavelengths. The gravity model has been derived from a reanalysis of the tracking data for Mariner 9 and the Viking Orbiters, The <span class="hlt">topography</span> model was derived by harmonic analysis of the USGS digital elevation model of Mars. Before comparing gravity and <span class="hlt">topography</span> for internal structure inferences, we must ensure that both are consistently referenced to a hydrostatic datum. For the gravity, this involves removal of hydrostatic components of the even degree zonal coefficients. For the <span class="hlt">topography</span>, it involves adding the degree 4 equipotential reference surface, to get spherically referenced values, and then subtracting the full degree 50 equipotential. Variance spectra and phase coherence of orthometric heights and gravity anomalies are addressed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20060043634&hterms=Topography&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DTopography','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20060043634&hterms=Topography&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DTopography"><span id="translatedtitle">Satellite remote sensing of landscape freeze/thaw state <span class="hlt">dynamics</span> for complex <span class="hlt">Topography</span> and Fire Disturbance Areas Using multi-sensor radar and SRTM digital elevation models</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Podest, Erika; McDonald, Kyle; Kimball, John; Randerson, James</p> <p>2003-01-01</p> <p>We characterize differences in radar-derived freeze/thaw state, examining transitions over complex terrain and landscape disturbance regimes. In areas of complex terrain, we explore freezekhaw <span class="hlt">dynamics</span> related to elevation, slope aspect and varying landcover. In the burned regions, we explore the timing of seasonal freeze/thaw transition as related to the recovering landscape, relative to that of a nearby control site. We apply in situ biophysical measurements, including flux tower measurements to validate and interpret the remotely sensed parameters. A multi-scale analysis is performed relating high-resolution SAR backscatter and moderate resolution scatterometer measurements to assess trade-offs in spatial and temporal resolution in the remotely sensed fields.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/16463910','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/16463910"><span id="translatedtitle">Implants as <span class="hlt">absolute</span> anchorage.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rungcharassaeng, Kitichai; Kan, Joseph Y K; Caruso, Joseph M</p> <p>2005-11-01</p> <p>Anchorage control is essential for successful orthodontic treatment. Each tooth has its own anchorage potential as well as propensity to move when force is applied. When teeth are used as anchorage, the untoward movements of the anchoring units may result in the prolonged treatment time, and unpredictable or less-than-ideal outcome. To maximize tooth-related anchorage, techniques such as differential torque, placing roots into the cortex of the bone, the use of various intraoral devices and/or extraoral appliances have been implemented. Implants, as they are in direct contact with bone, do not possess a periodontal ligament. As a result, they do not move when orthodontic/orthopedic force is applied, and therefore can be used as "<span class="hlt">absolute</span> anchorage." This article describes different types of implants that have been used as orthodontic anchorage. Their clinical applications and limitations are also discussed. PMID:16463910</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20040110742','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20040110742"><span id="translatedtitle"><span class="hlt">Absolute</span> Equilibrium Entropy</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Shebalin, John V.</p> <p>1997-01-01</p> <p>The entropy associated with <span class="hlt">absolute</span> equilibrium ensemble theories of ideal, homogeneous, fluid and magneto-fluid turbulence is discussed and the three-dimensional fluid case is examined in detail. A sigma-function is defined, whose minimum value with respect to global parameters is the entropy. A comparison is made between the use of global functions sigma and phase functions H (associated with the development of various H-theorems of ideal turbulence). It is shown that the two approaches are complimentary though conceptually different: H-theorems show that an isolated system tends to equilibrium while sigma-functions allow the demonstration that entropy never decreases when two previously isolated systems are combined. This provides a more complete picture of entropy in the statistical mechanics of ideal fluids.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AIPC.1382...49W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AIPC.1382...49W"><span id="translatedtitle"><span class="hlt">Absolute</span> neutrino mass measurements</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wolf, Joachim</p> <p>2011-10-01</p> <p>The neutrino mass plays an important role in particle physics, astrophysics and cosmology. In recent years the detection of neutrino flavour oscillations proved that neutrinos carry mass. However, oscillation experiments are only sensitive to the mass-squared difference of the mass eigenvalues. In contrast to cosmological observations and neutrino-less double beta decay (0v2β) searches, single β-decay experiments provide a direct, model-independent way to determine the <span class="hlt">absolute</span> neutrino mass by measuring the energy spectrum of decay electrons at the endpoint region with high accuracy. Currently the best kinematic upper limits on the neutrino mass of 2.2eV have been set by two experiments in Mainz and Troitsk, using tritium as beta emitter. The next generation tritium β-experiment KATRIN is currently under construction in Karlsruhe/Germany by an international collaboration. KATRIN intends to improve the sensitivity by one order of magnitude to 0.2eV. The investigation of a second isotope (137Rh) is being pursued by the international MARE collaboration using micro-calorimeters to measure the beta spectrum. The technology needed to reach 0.2eV sensitivity is still in the R&D phase. This paper reviews the present status of neutrino-mass measurements with cosmological data, 0v2β decay and single β-decay.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21611867','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21611867"><span id="translatedtitle"><span class="hlt">Absolute</span> neutrino mass measurements</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Wolf, Joachim</p> <p>2011-10-06</p> <p>The neutrino mass plays an important role in particle physics, astrophysics and cosmology. In recent years the detection of neutrino flavour oscillations proved that neutrinos carry mass. However, oscillation experiments are only sensitive to the mass-squared difference of the mass eigenvalues. In contrast to cosmological observations and neutrino-less double beta decay (0v2{beta}) searches, single {beta}-decay experiments provide a direct, model-independent way to determine the <span class="hlt">absolute</span> neutrino mass by measuring the energy spectrum of decay electrons at the endpoint region with high accuracy.Currently the best kinematic upper limits on the neutrino mass of 2.2eV have been set by two experiments in Mainz and Troitsk, using tritium as beta emitter. The next generation tritium {beta}-experiment KATRIN is currently under construction in Karlsruhe/Germany by an international collaboration. KATRIN intends to improve the sensitivity by one order of magnitude to 0.2eV. The investigation of a second isotope ({sup 137}Rh) is being pursued by the international MARE collaboration using micro-calorimeters to measure the beta spectrum. The technology needed to reach 0.2eV sensitivity is still in the R and D phase. This paper reviews the present status of neutrino-mass measurements with cosmological data, 0v2{beta} decay and single {beta}-decay.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.A41C3058W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.A41C3058W"><span id="translatedtitle">The Role of African <span class="hlt">topography</span> in the South Asian Monsoon</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wei, H. H.; Bordoni, S.</p> <p>2014-12-01</p> <p>The Somali cross-equatorial jet is estimated to contribute up to half of the mass flux crossing the equator during the Asian monsoon season. Previous studies have argued that the Somali jet is strengthened by the East African Highlands, which act as a wall and accelerate the flow (e.g., Krishnamurti et al. 1976, Sashegyi and Geisler 1987). Besides, observational studies have shown a positive correlation between the strength of the Somali jet and the South Asian Monsoon (SAM) precipitation (e.g., Findlater 1969, Halpern and Woiceshyn 2001). These imply that the existence of the <span class="hlt">topography</span> would relate to a stronger SAM. However, in a more recent study, Chakraborty et al. (2002) found that if the African <span class="hlt">topography</span> is removed in a comprehensive general circulation model (GCM), the SAM strengthens. In this study, we use the GFDL AM2.1 GCM to conduct experiments with and without <span class="hlt">topography</span> in Africa, to further examine its influence on the cross-equatorial Somali jet and the SAM. We find that when the African <span class="hlt">topography</span> is removed, the SAM precipitation increases, consistent with the results in Chakraborty et al. (2002). Interestingly, our results also show that the cross-equatorial Somali jet does weaken in the absence of the African <span class="hlt">topography</span>, in agreement with previous studies. The moisture budget shows that the increase in precipitation in the no-African <span class="hlt">topography</span> experiment is primarily due to stronger wind convergence. The <span class="hlt">dynamics</span> of the cross-equatorial Somali jet is investigated within the framework of the Potential Vorticity (PV) budget, showing the contribution of the changes in friction and diabatic heating to the circulation as the <span class="hlt">topography</span> is removed. A backward trajectory analysis is also conducted to further examine the influence of <span class="hlt">topography</span> on both the material tendencies of the PV budget and trajectories of parcels reaching the Indian subcontinent.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25186903','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25186903"><span id="translatedtitle">Asymmetric three-dimensional <span class="hlt">topography</span> over mantle plumes.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Burov, Evgueni; Gerya, Taras</p> <p>2014-09-01</p> <p>The role of mantle-lithosphere interactions in shaping surface <span class="hlt">topography</span> has long been debated. In general, it is supposed that mantle plumes and vertical mantle flows result in axisymmetric, long-wavelength <span class="hlt">topography</span>, which strongly differs from the generally asymmetric short-wavelength <span class="hlt">topography</span> created by intraplate tectonic forces. However, identification of mantle-induced <span class="hlt">topography</span> is difficult, especially in the continents. It can be argued therefore that complex brittle-ductile rheology and stratification of the continental lithosphere result in short-wavelength modulation and localization of deformation induced by mantle flow. This deformation should also be affected by far-field stresses and, hence, interplay with the 'tectonic' <span class="hlt">topography</span> (for example, in the 'active/passive' rifting scenario). Testing these ideas requires fully coupled three-dimensional numerical modelling of mantle-lithosphere interactions, which so far has not been possible owing to the conceptual and technical limitations of earlier approaches. Here we present new, ultra-high-resolution, three-dimensional numerical experiments on <span class="hlt">topography</span> over mantle plumes, incorporating a weakly pre-stressed (ultra-slow spreading), rheologically realistic lithosphere. The results show complex surface evolution, which is very different from the smooth, radially symmetric patterns usually assumed as the canonical surface signature of mantle upwellings. In particular, the <span class="hlt">topography</span> exhibits strongly asymmetric, small-scale, three-dimensional features, which include narrow and wide rifts, flexural flank uplifts and fault structures. This suggests a dominant role for continental rheological structure and intra-plate stresses in controlling <span class="hlt">dynamic</span> <span class="hlt">topography</span>, mantle-lithosphere interactions, and continental break-up processes above mantle plumes. PMID:25186903</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016SGeo...37..339P&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016SGeo...37..339P&link_type=ABSTRACT"><span id="translatedtitle">Toward a High-Resolution Monitoring of Continental Surface Water Extent and <span class="hlt">Dynamics</span>, at Global Scale: from GIEMS (Global Inundation Extent from Multi-Satellites) to SWOT (Surface Water Ocean <span class="hlt">Topography</span>)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Prigent, Catherine; Lettenmaier, Dennis P.; Aires, Filipe; Papa, Fabrice</p> <p>2016-03-01</p> <p>Up to now, high-resolution mapping of surface water extent from satellites has only been available for a few regions, over limited time periods. The extension of the temporal and spatial coverage was difficult, due to the limitation of the remote sensing technique [e.g., the interaction of the radiation with vegetation or cloud for visible observations or the temporal sampling with the synthetic aperture radar (SAR)]. The advantages and the limitations of the various satellite techniques are reviewed. The need to have a global and consistent estimate of the water surfaces over long time periods triggered the development of a multi-satellite methodology to obtain consistent surface water all over the globe, regardless of the environments. The Global Inundation Extent from Multi-satellites (GIEMS) combines the complementary strengths of satellite observations from the visible to the microwave, to produce a low-resolution monthly dataset (0.25^circ × 0.25^circ) of surface water extent and <span class="hlt">dynamics</span>. Downscaling algorithms are now developed and applied to GIEMS, using high-spatial-resolution information from visible, near-infrared, and synthetic aperture radar (SAR) satellite images, or from digital elevation models. Preliminary products are available down to 500-m spatial resolution. This work bridges the gaps and prepares for the future NASA/CNES Surface Water Ocean <span class="hlt">Topography</span> (SWOT) mission to be launched in 2020. SWOT will delineate surface water extent estimates and their water storage with an unprecedented spatial resolution and accuracy, thanks to a SAR in an interferometry mode. When available, the SWOT data will be adopted to downscale GIEMS, to produce a long time series of water surfaces at global scale, consistent with the SWOT observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=effect+AND+assimilation&pg=7&id=EJ735377','ERIC'); return false;" href="http://eric.ed.gov/?q=effect+AND+assimilation&pg=7&id=EJ735377"><span id="translatedtitle"><span class="hlt">Absolute</span> Identification by Relative Judgment</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Stewart, Neil; Brown, Gordon D. A.; Chater, Nick</p> <p>2005-01-01</p> <p>In unidimensional <span class="hlt">absolute</span> identification tasks, participants identify stimuli that vary along a single dimension. Performance is surprisingly poor compared with discrimination of the same stimuli. Existing models assume that identification is achieved using long-term representations of <span class="hlt">absolute</span> magnitudes. The authors propose an alternative…</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_10 --> <div id="page_11" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="201"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=VALUE+AND+ABSOLUTE&id=EJ765743','ERIC'); return false;" href="http://eric.ed.gov/?q=VALUE+AND+ABSOLUTE&id=EJ765743"><span id="translatedtitle">Be Resolute about <span class="hlt">Absolute</span> Value</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Kidd, Margaret L.</p> <p>2007-01-01</p> <p>This article explores how conceptualization of <span class="hlt">absolute</span> value can start long before it is introduced. The manner in which <span class="hlt">absolute</span> value is introduced to students in middle school has far-reaching consequences for their future mathematical understanding. It begins to lay the foundation for students' understanding of algebra, which can change…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1815060L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1815060L"><span id="translatedtitle">Statistics of <span class="hlt">topography</span> : multifractal approach to describe planetary <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Landais, Francois; Schmidt, Frédéric; Lovejoy, Shaun</p> <p>2016-04-01</p> <p>In the last decades, a huge amount of topographic data has been obtained by several techniques (laser and radar altimetry, DTM…) for different bodies in the solar system. In each case, topographic fields exhibit an extremely high variability with details at each scale, from millimeters to thousands of kilometers. In our study, we investigate the statistical properties of the <span class="hlt">topography</span>. Our statistical approach is motivated by the well known scaling behavior of <span class="hlt">topography</span> that has been widely studied in the past. Indeed, scaling laws are strongly present in geophysical field and can be studied using fractal formalism. More precisely, we expect multifractal behavior in global topographic fields. This behavior reflects the high variability and intermittency observed in topographic fields that can not be generated by simple scaling models. In the multifractal formalism, each statistical moment exhibits a different scaling law characterized by a function called the moment scaling function. Previous studies were conducted at regional scale to demonstrate that <span class="hlt">topography</span> present multifractal statistics (Gagnon et al., 2006, NPG). We have obtained similar results on Mars (Landais et al. 2015) and more recently on different body in the the solar system including the Moon, Venus and Mercury. We present the result of different multifractal approaches performed on global and regional basis and compare the fractal parameters from a body to another.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19870011267','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19870011267"><span id="translatedtitle">Linear baroclinic instability in the presence of large scale <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Reynolds, Nathaniel Dunton</p> <p>1987-01-01</p> <p>The effect of a planetary-scale, wavenumber 2 <span class="hlt">topography</span> on baroclinically active disturbances is investigated for a channel domain in a two-layer, quasi-geostrophic context. When the lower-layer zonal velocity is nonzero, the <span class="hlt">topography</span> influences the disturbances by forcing a stationary wave, and the <span class="hlt">topography</span> and the forced wave influence the growth rates and the spatial structures of the time-dependent solutions. The case of zero zonal velocity in the lower layer was also investigated, for which no forced wave exists. Asymptotic forms of the equations, valid when the topographic effect (governed by the ratio of the nondimensional topographic height to the rotational Froude number) is small, are used to obtain both the stationary and time-dependent solutions. The latter are also obtained using a numerical approach, in which is determined the eigenvalues and eigenfunctions of a matrix representing the <span class="hlt">dynamical</span> equations. Agreement is good between the two approaches. Recent laboratory experiments with a baroclinic annulus in which there is a false bottom with wavenumber 2 <span class="hlt">topography</span>, are used to select governing parameters. The simultaneous presence of a stationary forced wave of wavenumber 2 and a time-dependent baroclinic wave of wavenumber 4, which has wavenumber 2 and 6 sidebands due to the <span class="hlt">topography</span>, yields a flow field that exhibits some principal features of the laboratory experiments. The position of the forced wave and the location of an excursion in latitude of the storm track show qualitative resemblance to those features observed in the atmosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.3382H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.3382H"><span id="translatedtitle">Controls on (anomalous) <span class="hlt">topography</span> in rifted margin settings</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Huismans, Ritske S.</p> <p>2015-04-01</p> <p>Contrasting end members of volcanic and non-volcanic passive margin formation show a large variability in basin shape and structure, subsidence history, and associated topographic evolution of the onshore rifted margins. The large range of structural style and associated <span class="hlt">topography</span> of these systems imply a strong variability in the underlying thermo-mechanical conditions at the time of rifting. Rift - passive margin styles ranging from narrow to ultra wide are explained using forward numerical models with varying rheological structure, with strong crust lithosphere leading to narrow rift formation associated with highly elevated rift shoulders and conversely weak crust lithosphere resulting in highly stretched wide rifted conjugate margins and little flank morphology. In some cases rifted margins appear to indicate the formation of anomalous post rift <span class="hlt">topography</span>. A number of mechanisms including small-scale convective removal of the lower lithosphere, lithosphere counter-flow, and <span class="hlt">dynamic</span> <span class="hlt">topography</span>, have been invoked to explain the anomalous <span class="hlt">topography</span>. Forward numerical models are used to predict the magnitude and characteristic <span class="hlt">topography</span> associated with each of these mechanisms and to evaluate their potential for explaining these apparent anomalous characteristics of rifts and rifted margins.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19890001054','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19890001054"><span id="translatedtitle">Earth rotation and core <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hager, Bradford H.; Clayton, Robert W.; Spieth, Mary Ann</p> <p>1988-01-01</p> <p>The NASA Geodynamics program has as one of its missions highly accurate monitoring of polar motion, including changes in length of day (LOD). These observations place fundamental constraints on processes occurring in the atmosphere, in the mantle, and in the core of the planet. Short-timescale (t less than or approx 1 yr) variations in LOD are mainly the result of interaction between the atmosphere and the solid earth, while variations in LOD on decade timescales result from the exchange of angular momentum between the mantle and the fluid core. One mechanism for this exchange of angular momentum is through topographic coupling between pressure variations associated with flow in the core interacting with <span class="hlt">topography</span> at the core-mantel boundary (CMB). Work done under another NASA grant addressing the origin of long-wavelength geoid anomalies as well as evidence from seismology, resulted in several models of CMB <span class="hlt">topography</span>. The purpose of work supported by NAG5-819 was to study further the problem of CMB <span class="hlt">topography</span>, using geodesy, fluid mechanics, geomagnetics, and seismology. This is a final report.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19930043862&hterms=Mars+planet&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DMars%2Bplanet','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19930043862&hterms=Mars+planet&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DMars%2Bplanet"><span id="translatedtitle">Gravity and <span class="hlt">topography</span>. [of planet Mars</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Esposito, P. B.; Banerdt, W. B.; Lindal, G. F.; Sjogren, W. L.; Slade, M. A.; Bills, B. G.; Smith, D. E.; Balmino, G.</p> <p>1992-01-01</p> <p>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, <span class="hlt">dynamical</span> 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 <span class="hlt">topography</span>, inferences are made about the degree and depth of compensation in the interior and stresses in the lithosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5927137','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5927137"><span id="translatedtitle">Stresses in a submarine <span class="hlt">topography</span> under ocean waves</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Mei, C.C.; McTigue, D.F.</p> <p>1984-09-01</p> <p>The problem of submarine slope stability is of interest to both offshore engineering and geology. In an uneven <span class="hlt">topography</span>, the weight above a horizontal plane induces two-dimensional variation in the static stress field. The action of wave pressure, which changes with depth, further introduces excess pore pressure and <span class="hlt">dynamic</span> stresses in the sea bottom. In the present paper, we combine a simple analytical theory for the static stress by the present authors, and the recent solution by Mei and Foda for wave-induced stresses in a plane poro-elastic sea bed to account for mild bottom slope and wave shoaling, and obtain the effective stress field in a submarine <span class="hlt">topography</span> under sea waves. Sample results are given for a ridge and a canyon. In particular, the <span class="hlt">dynamic</span> pore pressure and the combined static and <span class="hlt">dynamic</span> effective stresses are presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5268545','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5268545"><span id="translatedtitle">Stresses in a submarine <span class="hlt">topography</span> under ocean waves</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Mei, C.C.; McTigue, D.F.</p> <p>1984-01-01</p> <p>The problem of submarine slope stability is of interest to both offshore engineering and geology. In an uneven <span class="hlt">topography</span>, the weight above a horizontal plane induces two-dimensional variation in the static stress field. The action of wave pressure, which changes with depth, further introduces excess pore pressure and <span class="hlt">dynamic</span> stresses in the sea bottom. In the present paper, we combine a simple analytical theory for the static stress by the present authors, and the recent solution by Mei and Foda for wave-induced stresses in a plane poro-elastic sea bed to account for mild bottom slope and wave shoaling, to obtain the effective stress field in a submarine <span class="hlt">topography</span> under sea waves. Sample results are given for a ridge and a canyon. In particular the <span class="hlt">dynamic</span> pore pressure and the combined static and <span class="hlt">dynamic</span> effective stresses are presented. 10 references, 11 figures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25500860','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25500860"><span id="translatedtitle">Corneal <span class="hlt">topography</span> matching by iterative registration.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wang, Junjie; Elsheikh, Ahmed; Davey, Pinakin G; Wang, Weizhuo; Bao, Fangjun; Mottershead, John E</p> <p>2014-11-01</p> <p>Videokeratography is used for the measurement of corneal <span class="hlt">topography</span> in overlapping portions (or maps) which must later be joined together to form the overall <span class="hlt">topography</span> of the cornea. The separate portions are measured from different viewpoints and therefore must be brought together by registration of measurement points in the regions of overlap. The central map is generally the most accurate, but all maps are measured with uncertainty that increases towards the periphery. It becomes the reference (or static) map, and the peripheral (or <span class="hlt">dynamic</span>) maps must then be transformed by rotation and translation so that the overlapping portions are matched. The process known as registration, of determining the necessary transformation, is a well-understood procedure in image analysis and has been applied in several areas of science and engineering. In this article, direct search optimisation using the Nelder-Mead algorithm and several variants of the iterative closest/corresponding point routine are explained and applied to simulated and real clinical data. The measurement points on the static and <span class="hlt">dynamic</span> maps are generally different so that it becomes necessary to interpolate, which is done using a truncated series of Zernike polynomials. The point-to-plane iterative closest/corresponding point variant has the advantage of releasing certain optimisation constraints that lead to persistent registration and alignment errors when other approaches are used. The point-to-plane iterative closest/corresponding point routine is found to be robust to measurement noise, insensitive to starting values of the transformation parameters and produces high-quality results when using real clinical data. PMID:25500860</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3016849','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3016849"><span id="translatedtitle"><span class="hlt">Topography</span>, Cell Response, and Nerve Regeneration</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Hoffman-Kim, Diane; Mitchel, Jennifer A.; Bellamkonda, Ravi V.</p> <p>2010-01-01</p> <p>In the body, cells encounter a complex milieu of signals, including topographical cues. Imposed <span class="hlt">topography</span> can affect cells on surfaces by promoting adhesion, spreading, alignment, morphological changes, and changes in gene expression. Neural response to <span class="hlt">topography</span> 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 <span class="hlt">topographies</span>. How neurons and other cell types sense and interpret <span class="hlt">topography</span> remains to be fully elucidated. Studies reviewed here include those of <span class="hlt">topography</span> on cellular organization and function as well as potential cellular mechanisms of response. PMID:20438370</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EPSC...10..514S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EPSC...10..514S"><span id="translatedtitle">Estimation of Ganymede's <span class="hlt">Topography</span>, Rotation and Tidal Deformation - a Study of Synthetic Ganymede Laser Altimeter Observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Steinke, T.; Stark, A.; Steinbrügge, G.; Hussmann, H.; Oberst, J.</p> <p>2015-10-01</p> <p>We implement an iterative least-squares inversion routine to study the estimation of several <span class="hlt">dynamic</span> Ganymede rotation parameters by laser altimetry. Based on spherical harmonic expansions of the global <span class="hlt">topography</span> we use simulated Ganymede Laser Al-timeter observations representing the synthetic <span class="hlt">topography</span> of the satellite. Besides the static <span class="hlt">topography</span> we determine the <span class="hlt">dynamical</span> parameters, such as the rotation rate, the amplitudes of physical librations, the spin pole orientation, and the tidal deformation. This parameters may strengthen implications for a liquid ocean beneath Ganymede's icy shell and, in addition, constrain geodetic frame parameters essential for various space-borne experiments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27581485','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27581485"><span id="translatedtitle">Transient <span class="hlt">absolute</span> robustness in stochastic biochemical networks.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Enciso, German A</p> <p>2016-08-01</p> <p><span class="hlt">Absolute</span> robustness allows biochemical networks to sustain a consistent steady-state output in the face of protein concentration variability from cell to cell. This property is structural and can be determined from the topology of the network alone regardless of rate parameters. An important question regarding these systems is the effect of discrete biochemical noise in the <span class="hlt">dynamical</span> behaviour. In this paper, a variable freezing technique is developed to show that under mild hypotheses the corresponding stochastic system has a transiently robust behaviour. Specifically, after finite time the distribution of the output approximates a Poisson distribution, centred around the deterministic mean. The approximation becomes increasingly accurate, and it holds for increasingly long finite times, as the total protein concentrations grow to infinity. In particular, the stochastic system retains a transient, <span class="hlt">absolutely</span> robust behaviour corresponding to the deterministic case. This result contrasts with the long-term <span class="hlt">dynamics</span> of the stochastic system, which eventually must undergo an extinction event that eliminates robustness and is completely different from the deterministic <span class="hlt">dynamics</span>. The transiently robust behaviour may be sufficient to carry out many forms of robust signal transduction and cellular decision-making in cellular organisms. PMID:27581485</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24243093','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24243093"><span id="translatedtitle">Effect of <span class="hlt">topography</span> on sulfate redistribution in Cumulonimbus cloud development.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Vujović, Dragana; Vučković, Vladan; Curić, Mlađen</p> <p>2014-03-01</p> <p>An aqueous chemical module is created and included into a complex three-dimensional atmospheric cloud-resolving mesoscale model. In the chemical module, oxidation of S(IV) by ozone and hydrogen peroxide in cloud-water and rainwater, as important process of the sulfate production is included. To examine the impact of <span class="hlt">topography</span> on the sulfate redistribution in a clean and a polluted environment, the complex <span class="hlt">topography</span> of Serbia is included in the model. Numerical simulations of an isolated summer Cumulonimbus cloud shows that thunderstorms generate very strong vertical sulfate redistribution from the planetary boundary layer to the upper troposphere. This redistribution is sensitive to cloud <span class="hlt">dynamics</span>, while cloud microphysics and precipitation determine wet removal of the chemical species. In simulations with realistic <span class="hlt">topography</span>, the chemical species are transported over larger distances close to the surface, while in the upper atmosphere, there is no difference compared to the simulations without <span class="hlt">topography</span>. The sensitivity tests of cloud chemistry to the physical processes are made. Omission of nucleation and impact scavenging of aerosols in the model simulations shows that 75.8 and 62.5 % of total sulfur mass deposited in the base experiment for the clean and the polluted environment, respectively, is the result of other processes. Exclusion of oxidation accounted for 19.2 and 37.7 % of total sulfur deposited for clean and polluted environment. Ignoring the ice phase almost not change mass of deposited sulfur: there is an increase of 2.9 and 1.5 % for clean and polluted atmosphere, respectively. Real <span class="hlt">topography</span> conditions affect the sulfate redistribution in the sense of greater possibilities of transport. Numerical simulations without real <span class="hlt">topography</span> give an artificial increase of deposited sulfur mass of about 25-30 %. PMID:24243093</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMED11B3407G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMED11B3407G"><span id="translatedtitle">The <span class="hlt">Topography</span> Tub Learning Activity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Glesener, G. B.</p> <p>2014-12-01</p> <p>Understanding the basic elements of a topographic map (i.e. contour lines and intervals) is just a small part of learning how to use this abstract representational system as a resource in geologic mapping. Interpretation of a topographic map and matching its features with real-world structures requires that the system is utilized for visualizing the shapes of these structures and their spatial orientation. To enrich students' skills in visualizing <span class="hlt">topography</span> from topographic maps a spatial training activity has been developed that uses 3D objects of various shapes and sizes, a sighting tool, a plastic basin, water, and transparencies. In the first part of the activity, the student is asked to draw a topographic map of one of the 3D objects. Next, the student places the object into a plastic tub in which water is added to specified intervals of height. The shoreline at each interval is used to reference the location of the contour line the student draws on a plastic inkjet transparency directly above the object. A key part of this activity is the use of a sighting tool by the student to assist in keeping the pencil mark directly above the shoreline. It (1) ensures the accurate positioning of the contour line and (2) gives the learner experience with using a sight before going out into the field. Finally, after the student finishes drawing the contour lines onto the transparency, the student can compare and contrast the two maps in order to discover where improvements in their visualization of the contours can be made. The teacher and/or peers can also make suggestions on ways to improve. A number of objects with various shapes and sizes are used in this exercise to produce contour lines representing the different types of <span class="hlt">topography</span> the student may encounter while field mapping. The intended outcome from using this visualization training activity is improvement in performance of visualizing <span class="hlt">topography</span> as the student moves between the topographic representation and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1989SPIE.1036...99Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1989SPIE.1036...99Y"><span id="translatedtitle">Precision Measurement Of Corneal <span class="hlt">Topography</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yoder, Paul R.; Macri, Timothy F.; Telfair, William B.; Bennett, Peter S.; Martin, Clifford A.; Warner, John W.</p> <p>1989-05-01</p> <p>We describe a new electro-optical device being developed to provide precise measurements of the three-dimensional <span class="hlt">topography</span> of the human cornea. This device, called a digital keratoscope, is intended primarily for use in preparing for and determining the effect of corneal surgery procedures such as laser refractive keratectomy, radial keratotomy or corneal transplant on the refractive power of the cornea. It also may serve as an aid in prescribing contact lenses. The basic design features of the hardware and of the associated computer software are discussed, the means for alignment and calibration are described and typical results are given.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AGUSM...S21B02G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AGUSM...S21B02G"><span id="translatedtitle">Simultaneous inversion for mantle shear velocity and the <span class="hlt">topography</span> of transition zone discontinuities</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gu, Y. J.; Dziewonski, A. M.</p> <p>2001-05-01</p> <p>A method is presented for the simultaneous inversions of shear velocity in the mantle and the <span class="hlt">topography</span> of transition zone discontinuities. Each travel time residual, corrected for crust and free surface <span class="hlt">topography</span>, is modeled as resulting from contributions from three-dimensional shear velocity perturbations to a spherical Earth model and boundary undulations to the 410 and 660 km discontinuities. This approach minimizes tradeoffs between velocity and <span class="hlt">topography</span>. We expand the lateral variations in velocity and the <span class="hlt">topography</span> of each discontinuity using 362 spherical B-splines; we expand the radial variations using 14 cubic B-splines. To increase the reliability of the measurements, particularly in the undersampled southern hemisphere, we re-examine the <span class="hlt">topography</span> of the 410- and 660 km discontinuities from more than 21,000 SH-component records. This new data set is significantly larger than those used earlier studies of SS precursors. The long-wavelength features of our new <span class="hlt">topography</span> maps of the 410- and 660-km discontinuities are compatible with results of earlier studies: the large-scale patterns are dominated by low degree spherical harmonics, particularly at degrees 1 and 2. We also include an independent measurement of the global transition zone thickness for additional constraints on the structure in the transition zone. The best-fit model from the joint inversion reduces the variance of the <span class="hlt">absolute</span> and differential travel times of S, SS and ScS by 40 to 70 %, and the differential travel times of SS precursors by up to 90%.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AGUFM.H54C..04I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AGUFM.H54C..04I"><span id="translatedtitle">Aspects of Radiation Budget, Subsurface Lateral Moisture Exchange, and Vegetation Function in Areas of Complex <span class="hlt">Topography</span>.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ivanov, V. Y.; Bras, R. L.; Istanbulluoglu, E.; Vivoni, E. R.</p> <p>2004-12-01</p> <p>There is evidence that <span class="hlt">topography</span> strongly affects the state, function, and distribution of vegetation by controlling incoming solar radiation and lateral redistribution of soil moisture. However, numerical experiments studying the effects that a <span class="hlt">topography</span> can have on vegetation have oversimplified the treatment of <span class="hlt">topography</span> and/or the representation of vegetation. We investigate the control of <span class="hlt">topography</span> on vegetation state and stress via detailed modeling of radiation and soil moisture budgets across the varied terrain of a watershed. A detailed vegetation-hydrology model parameterizes the processes of canopy radiative transfer and rainfall interception and couples the processes of infiltration and evapotranspiration to photosynthesis via moisture uptake through a root systems with varied profiles. The model is applied on a continuous basis to synthetic watersheds of <span class="hlt">topography</span> dominated by either convex or concave hillslopes. The numerical analysis is carried out for several plant functional types and soils. Inferences from the spatially-distributed <span class="hlt">dynamics</span> are used to examine topographic niches favorable to vegetation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19720027445&hterms=isolated+neutral&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Disolated%2Bneutral','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19720027445&hterms=isolated+neutral&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Disolated%2Bneutral"><span id="translatedtitle"><span class="hlt">Absolute</span> transition probabilities of phosphorus.</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Miller, M. H.; Roig, R. A.; Bengtson, R. D.</p> <p>1971-01-01</p> <p>Use of a gas-driven shock tube to measure the <span class="hlt">absolute</span> strengths of 21 P I lines and 126 P II lines (from 3300 to 6900 A). Accuracy for prominent, isolated neutral and ionic lines is estimated to be 28 to 40% and 18 to 30%, respectively. The data and the corresponding theoretical predictions are examined for conformity with the sum rules.-</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012Tectp.526....5H&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012Tectp.526....5H&link_type=ABSTRACT"><span id="translatedtitle">Unraveling <span class="hlt">topography</span> around subduction zones from laboratory models</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Husson, Laurent; Guillaume, Benjamin; Funiciello, Francesca; Faccenna, Claudio; Royden, Leigh H.</p> <p>2012-03-01</p> <p>The relief around subduction zones results from the interplay of <span class="hlt">dynamic</span> processes that may locally exceed the (iso)static contributions. The viscous dissipation of the energy in and around subduction zones is capable of generating kilometer scale vertical ground movements. In order to evaluate <span class="hlt">dynamic</span> <span class="hlt">topography</span> in a self-consistent subduction system, we carried out a set of laboratory experiments, wherein the lithosphere and mantle are simulated by means of Newtonian viscous materials, namely silicone putty and glucose syrup. Models are kept in their most simple form and are made of negative buoyancy plates, of variable width and thickness, freely plunging into the syrup. The surface of the model and the top of the slab are scanned in three dimensions. A forebulge systematically emerges from the bending of the viscous plate, adjacent to the trench. With a large wavelength, <span class="hlt">dynamic</span> pressure offsets the foreside and backside of the slab by ~ 500 m on average. The suction, that accompanies the vertical descent of the slab depresses the surface on both sides. At a distance equal to the half-width of the slab, the topographic depression amounts to ~ 500 m on average and becomes negligible at a distance that equals the width of the slab. In order to explore the impact of slab rollback on the <span class="hlt">topography</span>, the trailing edge of the plates is alternatively fixed to (fixed mode) and freed from (free mode) the end wall of the tank. Both the pressure and suction components of the <span class="hlt">topography</span> are ~ 30% lower in the free mode, indicating that slab rollback fosters the <span class="hlt">dynamic</span> subsidence of upper plates. Our models are compatible with first order observations of the <span class="hlt">topography</span> around the East Scotia, Tonga, Kermadec and Banda subduction zones, which exhibit anomalous depths of nearly 1 km as compared to adjacent sea floor of comparable age.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMNG23A1772O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMNG23A1772O"><span id="translatedtitle">Spectral <span class="hlt">Topography</span> Generation for Arbitrary Grids</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Oh, T. J.</p> <p>2015-12-01</p> <p>A new <span class="hlt">topography</span> generation tool utilizing spectral transformation technique for both structured and unstructured grids is presented. For the source global digital elevation data, the NASA Shuttle Radar <span class="hlt">Topography</span> Mission (SRTM) 15 arc-second dataset (gap-filling by Jonathan de Ferranti) is used and for land/water mask source, the NASA Moderate Resolution Imaging Spectroradiometer (MODIS) 30 arc-second land water mask dataset v5 is used. The original source data is coarsened to a intermediate global 2 minute lat-lon mesh. Then, spectral transformation to the wave space and inverse transformation with wavenumber truncation is performed for isotropic <span class="hlt">topography</span> smoothness control. Target grid <span class="hlt">topography</span> mapping is done by bivariate cubic spline interpolation from the truncated 2 minute lat-lon <span class="hlt">topography</span>. Gibbs phenomenon in the water region can be removed by overwriting ocean masked target coordinate grids with interpolated values from the intermediate 2 minute grid. Finally, a weak smoothing operator is applied on the target grid to minimize the land/water surface height discontinuity that might have been introduced by the Gibbs oscillation removal procedure. Overall, the new <span class="hlt">topography</span> generation approach provides spectrally-derived, smooth <span class="hlt">topography</span> with isotropic resolution and minimum damping, enabling realistic <span class="hlt">topography</span> forcing in the numerical model. <span class="hlt">Topography</span> is generated for the cubed-sphere grid and tested on the KIAPS Integrated Model (KIM).</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_11 --> <div id="page_12" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="221"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.usgs.gov/imap/1726/plate-2.pdf','USGSPUBS'); return false;" href="http://pubs.usgs.gov/imap/1726/plate-2.pdf"><span id="translatedtitle">Bedrock <span class="hlt">topography</span> of northwest Iowa</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Hansen, R.E.; Runkle, D.L.</p> <p>1986-01-01</p> <p>Bedrock in Iowa (Hershey, 1969) generally is overlain by deposits of glacial drive and alluvium. The drift, consisting of glacial till and glacial outwash, ranges in thickness from zero to more than 500 feet in western Iowa; the alluvium in stream valleys ranges in thickness from less than 1 foot to more than 70 feet. The configuration of the bedrock surface is the result of a complex system of ancient drainage courses that were developed during a long period of preglacial erosion. This map, for a 12 county area in west-central Iowa, is the eighth in a series of nine reports that will provide statewide coverage of the bedriock <span class="hlt">topography</span> of Iowa. </p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19870014110','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19870014110"><span id="translatedtitle">Large scale <span class="hlt">topography</span> of Io</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gaskell, R. W.; Synnott, S. P.</p> <p>1987-01-01</p> <p>To investigate the large scale <span class="hlt">topography</span> of the Jovian satellite Io, both limb observations and stereographic techniques applied to landmarks are used. The raw data for this study consists of Voyager 1 images of Io, 800x800 arrays of picture elements each of which can take on 256 possible brightness values. In analyzing this data it was necessary to identify and locate landmarks and limb points on the raw images, remove the image distortions caused by the camera electronics and translate the corrected locations into positions relative to a reference geoid. Minimizing the uncertainty in the corrected locations is crucial to the success of this project. In the highest resolution frames, an error of a tenth of a pixel in image space location can lead to a 300 m error in true location. In the lowest resolution frames, the same error can lead to an uncertainty of several km.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JAGeo...8..195S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JAGeo...8..195S"><span id="translatedtitle"><span class="hlt">Absolute</span> Performance of AUSGeoid09 in Mountainous Regions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sussanna, Vittorio; Janssen, Volker; Gibbings, Peter</p> <p>2014-09-01</p> <p>The Australian Height Datum (AHD) is the current national vertical datum for Australia, and AUSGeoid09 is the latest quasigeoid model used to compute (normal-orthometric)AHDheights fromGlobalNavigation Satellite System (GNSS) derived ellipsoidal heights. While previous studies have evaluated the AUSGeoid09 model across Australia, such studies have not focused on mountainous regions in particular. This paper investigates the performance of AUSGeoid09 in an <span class="hlt">absolute</span> sense in the Mid Hunter and Snowy Mountains regions of New South Wales. <span class="hlt">Absolute</span> (i.e. single point) comparisons were undertaken between AUSGeoid09-derived heights and published AHD heights. The performance of AUSGeoid09 was evaluated relative to its predecessor AUSGeoid98. In both study areas, an overall improvement is evident when applying AUSGeoid09 to compute AHD heights in an <span class="hlt">absolute</span> sense. In the MidHunter, AUSGeoid09 provided a substantial improvement over its predecessor, clearly demonstrating the benefits of its new geometric component on GNSS-derived AHD height determination. In the Snowy Mountains, moderate improvement over AUSGeoid98 was evident. However, a slope was detected for AUSGeoid09 residuals, and it appears that the geometric component may have overcompensated for sea surface <span class="hlt">topography</span> in this area. While this appraisal of AUSGeoid09 performance in mountainous regions is encouraging, it has been shown that some discrepancies still remain between AUSGeoid09-derived heights and AHD. Eventually, a new vertical datum will be necessary to ensure homogeneity across Australia.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016PhRvA..94a3808D&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016PhRvA..94a3808D&link_type=ABSTRACT"><span id="translatedtitle">Optomechanics for <span class="hlt">absolute</span> rotation detection</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Davuluri, Sankar</p> <p>2016-07-01</p> <p>In this article, we present an application of optomechanical cavity for the <span class="hlt">absolute</span> rotation detection. The optomechanical cavity is arranged in a Michelson interferometer in such a way that the classical centrifugal force due to rotation changes the length of the optomechanical cavity. The change in the cavity length induces a shift in the frequency of the cavity mode. The phase shift corresponding to the frequency shift in the cavity mode is measured at the interferometer output to estimate the angular velocity of <span class="hlt">absolute</span> rotation. We derived an analytic expression to estimate the minimum detectable rotation rate in our scheme for a given optomechanical cavity. Temperature dependence of the rotation detection sensitivity is studied.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20100014902&hterms=asp&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dasp','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20100014902&hterms=asp&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dasp"><span id="translatedtitle">The <span class="hlt">Absolute</span> Spectrum Polarimeter (ASP)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kogut, A. J.</p> <p>2010-01-01</p> <p>The <span class="hlt">Absolute</span> Spectrum Polarimeter (ASP) is an Explorer-class mission to map the <span class="hlt">absolute</span> intensity and linear polarization of the cosmic microwave background and diffuse astrophysical foregrounds over the full sky from 30 GHz to 5 THz. The principal science goal is the detection and characterization of linear polarization from an inflationary epoch in the early universe, with tensor-to-scalar ratio r much greater than 1O(raised to the power of { -3}) and Compton distortion y < 10 (raised to the power of{-6}). We describe the ASP instrument and mission architecture needed to detect the signature of an inflationary epoch in the early universe using only 4 semiconductor bolometers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1175308','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1175308"><span id="translatedtitle"><span class="hlt">Absolute</span> calibration of optical flats</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Sommargren, Gary E.</p> <p>2005-04-05</p> <p>The invention uses the phase shifting diffraction interferometer (PSDI) to provide a true point-by-point measurement of <span class="hlt">absolute</span> flatness over the surface of optical flats. Beams exiting the fiber optics in a PSDI have perfect spherical wavefronts. The measurement beam is reflected from the optical flat and passed through an auxiliary optic to then be combined with the reference beam on a CCD. The combined beams include phase errors due to both the optic under test and the auxiliary optic. Standard phase extraction algorithms are used to calculate this combined phase error. The optical flat is then removed from the system and the measurement fiber is moved to recombine the two beams. The newly combined beams include only the phase errors due to the auxiliary optic. When the second phase measurement is subtracted from the first phase measurement, the <span class="hlt">absolute</span> phase error of the optical flat is obtained.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011PhRvS..14l3501X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011PhRvS..14l3501X"><span id="translatedtitle">Enhanced characterization of niobium surface <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xu, Chen; Tian, Hui; Reece, Charles E.; Kelley, Michael J.</p> <p>2011-12-01</p> <p>Surface <span class="hlt">topography</span> characterization is a continuing issue for the superconducting radio frequency (SRF) particle accelerator community. Efforts are under way to both improve surface <span class="hlt">topography</span> and its characterization and analysis using various techniques. In measurement of <span class="hlt">topography</span>, power spectral density (PSD) is a promising method to quantify typical surface parameters and develop scale-specific interpretations. PSD can also be used to indicate how the process modifies <span class="hlt">topography</span> at different scales. However, generating an accurate and meaningful topographic PSD of an SRF surface requires careful analysis and optimization. In this report, niobium surfaces with different process histories are sampled with atomic force microscopy and stylus profilometry and analyzed to trace <span class="hlt">topography</span> evolution at different scales. An optimized PSD analysis protocol to serve SRF needs is presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015GeoJI.203.1263K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015GeoJI.203.1263K"><span id="translatedtitle">High surface <span class="hlt">topography</span> related to upper mantle flow beneath Eastern Anatolia</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Komut, Tolga</p> <p>2015-11-01</p> <p>Eastern Anatolia region between north-south colliding Arabian and Eurasian plates has no significant crustal root and shallow (upper) mantle flow beneath seems to be vertically supporting its high <span class="hlt">topography</span>. It has a high surface heat flow and the underlying mantle is characterized by low seismic velocity zones. Using a mantle density/temperature variation field derived from P-wave seismic velocity, current shallow mantle flow and resultant <span class="hlt">dynamic</span> <span class="hlt">topography</span> of Eastern Anatolia and adjacent Arabian foreland and Caucasus areas were calculated along a vertical section. The section crosses the tectonic boundaries interrelated with slab bodies (high seismic velocity/cold regions) and the low velocity zones above the slabs. According to the modelling experiments, the surface <span class="hlt">topography</span> of Eastern Anatolia seems to be supported by shallow mantle flow <span class="hlt">dynamics</span>. On the other hand, residual <span class="hlt">topography</span> for the region was calculated using high resolution crustal thickness data. Positive residual <span class="hlt">topography</span> that suggests an undercompensated state of Eastern Anatolia is in concordance with the <span class="hlt">dynamic</span> <span class="hlt">topography</span> anomaly. The modelled local shallow mantle flow support due to the density contrast between hot (low velocity) zones and underlying cold slab bodies beneath the area may be the present-day snapshot of the mantle flow uplift in Eastern Anatolia presence of which was previously suggested.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://geology.er.usgs.gov/eespteam/terrainmodeling/ds_136.htm','USGSPUBS'); return false;" href="http://geology.er.usgs.gov/eespteam/terrainmodeling/ds_136.htm"><span id="translatedtitle"><span class="hlt">Topography</span> and Landforms of Ecuador</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Chirico, Peter G.; Warner, Michael B.</p> <p>2005-01-01</p> <p>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 <span class="hlt">Topography</span> 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</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011GeoRL..3816611V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011GeoRL..3816611V"><span id="translatedtitle">Stochastic variability of oceanic flows above <span class="hlt">topography</span> anomalies</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Venaille, A.; Le Sommer, J.; Molines, J.-M.; Barnier, B.</p> <p>2011-08-01</p> <p>We describe a stochastic variability mechanism which is genuinely internal to the ocean, i.e., not due to fluctuations in atmospheric forcing. The key ingredient is the existence of closed contours of bottom <span class="hlt">topography</span> surrounded by a stirring region of enhanced eddy activity. This configuration leads to the formation of a robust but highly variable vortex above the <span class="hlt">topography</span> anomaly. The vortex <span class="hlt">dynamics</span> integrates the white noise forcing of oceanic eddies into a red noise signal for the large scale volume transport of the vortex. The strong interannual fluctuations of the transport of the Zapiola anticyclone (˜100 Sv) in the Argentine basin are argued to be partly due to such eddy-driven stochastic variability, on the basis of a 310 years long simulation of a comprehensive global ocean model run driven by a repeated-year forcing.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3184154','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3184154"><span id="translatedtitle">Predicting Maximum Lake Depth from Surrounding <span class="hlt">Topography</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Hollister, Jeffrey W.; Milstead, W. Bryan; Urrutia, M. Andrea</p> <p>2011-01-01</p> <p>Information about lake morphometry (e.g., depth, volume, size, etc.) aids understanding of the physical and ecological <span class="hlt">dynamics</span> 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 <span class="hlt">topography</span> 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</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19720024184','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19720024184"><span id="translatedtitle"><span class="hlt">Absolute</span> calibration of ultraviolet filter photometry</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bless, R. C.; Fairchild, T.; Code, A. D.</p> <p>1972-01-01</p> <p>The essential features of the calibration procedure can be divided into three parts. First, the shape of the bandpass of each photometer was determined by measuring the transmissions of the individual optical components and also by measuring the response of the photometer as a whole. Secondly, each photometer was placed in the essentially-collimated synchrotron radiation bundle maintained at a constant intensity level, and the output signal was determined from about 100 points on the objective. Finally, two or three points on the objective were illuminated by synchrotron radiation at several different intensity levels covering the <span class="hlt">dynamic</span> range of the photometers. The output signals were placed on an <span class="hlt">absolute</span> basis by the electron counting technique described earlier.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/910204','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/910204"><span id="translatedtitle"><span class="hlt">Absolute</span> Measurement of Electron Cloud Density</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Covo, M K; Molvik, A W; Cohen, R H; Friedman, A; Seidl, P A; Logan, G; Bieniosek, F; Baca, D; Vay, J; Orlando, E; Vujic, J L</p> <p>2007-06-21</p> <p>Beam interaction with background gas and walls produces ubiquitous clouds of stray electrons that frequently limit the performance of particle accelerator and storage rings. Counterintuitively we obtained the electron cloud accumulation by measuring the expelled ions that are originated from the beam-background gas interaction, rather than by measuring electrons that reach the walls. The kinetic ion energy measured with a retarding field analyzer (RFA) maps the depressed beam space-charge potential and provides the <span class="hlt">dynamic</span> electron cloud density. Clearing electrode current measurements give the static electron cloud background that complements and corroborates with the RFA measurements, providing an <span class="hlt">absolute</span> measurement of electron cloud density during a 5 {micro}s duration beam pulse in a drift region of the magnetic transport section of the High-Current Experiment (HCX) at LBNL.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.usgs.gov/fs/2009/3087/','USGSPUBS'); return false;" href="http://pubs.usgs.gov/fs/2009/3087/"><span id="translatedtitle">Shuttle Radar <span class="hlt">Topography</span> Mission (SRTM)</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>U.S. Geological Survey</p> <p>2009-01-01</p> <p>Under an agreement with the National Aeronautics and Space Administration (NASA) and the Department of Defense's National Geospatial-Intelligence Agency (NGA), the U.S. Geological Survey (USGS) is distributing elevation data from the Shuttle Radar <span class="hlt">Topography</span> Mission (SRTM). The SRTM is a joint project of NASA and NGA to map the Earth's land surface in three dimensions at an unprecedented level of detail. As part of space shuttle Endeavour's flight during February 11-22, 2000, the SRTM successfully collected data over 80 percent of the Earth's land surface for most of the area between latitudes 60 degrees north and 56 degrees south. The SRTM hardware included the Spaceborne Imaging Radar-C (SIR-C) and X-band Synthetic Aperture Radar (X-SAR) systems that had flown twice previously on other space shuttle missions. The SRTM data were collected with a technique known as interferometry that allows image data from dual radar antennas to be processed for the extraction of ground heights.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.usgs.gov/fs/2003/0071/report.pdf','USGSPUBS'); return false;" href="http://pubs.usgs.gov/fs/2003/0071/report.pdf"><span id="translatedtitle">Shuttle Radar <span class="hlt">Topography</span> Mission (SRTM)</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>U.S. Geological Survey</p> <p>2003-01-01</p> <p>Under an agreement with the National Aeronautics and Space Administration (NASA) and the Department of Defense's National Imagery and Mapping Agency (NIMA), the U.S. Geological Survey (USGS) is now distributing elevation data from the Shuttle Radar <span class="hlt">Topography</span> Mission (SRTM). The SRTM is a joint project between NASA and NIMA to map the Earth's land surface in three dimensions at a level of detail unprecedented for such a large area. Flown aboard the NASA Space Shuttle Endeavour February 11-22, 2000, the SRTM successfully collected data over 80 percent of the Earth's land surface, for most of the area between 60? N. and 56? S. latitude. The SRTM hardware included the Spaceborne Imaging Radar-C (SIR-C) and X-band Synthetic Aperture Radar (X-SAR) systems that had flown twice previously on other space shuttle missions. The SRTM data were collected specifically with a technique known as interferometry that allows image data from dual radar antennas to be processed for the extraction of ground heights.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950027808&hterms=Binocular+vision&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DBinocular%2Bvision','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950027808&hterms=Binocular+vision&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DBinocular%2Bvision"><span id="translatedtitle"><span class="hlt">Topography</span> from shading and stereo</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Horn, Berthold P.; Caplinger, Michael</p> <p>1993-01-01</p> <p>Methods exploiting photometric information in images that have been developed in machine vision can be applied to planetary imagery. Present techniques, however, focus on one visual cue, such as shading or binocular stereo, and produce results that are either not very accurate in an <span class="hlt">absolute</span> sense or provide information only at few points on the surface. We plan to integrate shape from shading, binocular stereo and photometric stereo to yield a robust system for recovering detailed surface shape and surface reflectance information. Such a system will be useful in producing quantitative information from the vast volume of imagery being received, as well as in helping visualize the underlying surface. The work will be carried out on a popular computing platform so that it will be easily accessible to other workers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19930016614&hterms=Binocular+vision&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DBinocular%2Bvision','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19930016614&hterms=Binocular+vision&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DBinocular%2Bvision"><span id="translatedtitle"><span class="hlt">Topography</span> from shading and stereo</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Horn, Berthold P.; Caplinger, Michael</p> <p>1992-01-01</p> <p>Methods exploiting photometric information in images that have been developed in machine vision can be applied to planetary imagery. Present techniques, however, focus on one visual cue, such as shading or binocular stereo, and produce results that are either not very accurate in an <span class="hlt">absolute</span> sense or provide information only at few points on the surface. We plan to integrate shape from shading, binocular stereo and photometric stereo to yield a robust system for recovering detailed surface shape and surface reflectance information. Such a system will be useful in producing quantitative information from the vast volume of imagery being received, as well as in helping visualize the underlying surface. The work will be carried out on a popular computing platform so that it will be easily accessible to other workers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19790013324','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19790013324"><span id="translatedtitle">The AFGL <span class="hlt">absolute</span> gravity program</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hammond, J. A.; Iliff, R. L.</p> <p>1978-01-01</p> <p>A brief discussion of the AFGL's (Air Force Geophysics Laboratory) program in <span class="hlt">absolute</span> gravity is presented. Support of outside work and in-house studies relating to gravity instrumentation are discussed. A description of the current transportable system is included and the latest results are presented. These results show good agreement with measurements at the AFGL site by an Italian system. The accuracy obtained by the transportable apparatus is better than 0.1 microns sq sec 10 microgal and agreement with previous measurements is within the combined uncertainties of the measurements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AGUSM...B41C08F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AGUSM...B41C08F"><span id="translatedtitle">The Shuttle Radar <span class="hlt">Topography</span> Mission</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Farr, T. G.; Kobrick, M.</p> <p>2001-05-01</p> <p>The Shuttle Radar <span class="hlt">Topography</span> Mission (SRTM), which flew successfully aboard Endeavour in February 2000, is a cooperative project between NASA and the National Imagery and Mapping Agency (NIMA). The mission was designed to use a single-pass radar interferometer to produce a digital elevation model of the Earth's land surface between about 60 degrees north and 56 degrees south latitude. The DEM will have 30 m horizontal resolution and about 15 m vertical errors. Two ortho-rectified C-band image mosaics are also planned. SRTM used a modification of the radar instrument that comprised the Spaceborne Radar Laboratory that flew twice on the Shuttle Endeavour in 1994. To collect the interferometric data, a 60 m mast, additional C-band antenna, and improved tracking and navigation devices were added. A second X-band antenna was also added by the German Space Agency, and produced higher resolution topographic measurements in strips nested within the full, C-band coverage. First results indicate that the radars and ancillary instruments worked very well. Data played back to the ground during the flight were processed to DEMs and products released hours after acquisition. An extensive program for calibration and verification of the SRTM data is now underway. When complete later this year, systematic processing of the data will begin, with final products emerging a continent at a time. Data processing will be completed by the end of 2002. Products will be transferred to the US Geological Survey's EROS Data Center for civilian archive and distribution. NIMA will handle Department of Defense distribution. * Work performed under contract to NASA.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AGUFM.G22B0214F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AGUFM.G22B0214F"><span id="translatedtitle">The Shuttle Radar <span class="hlt">Topography</span> Mission</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Farr, T. G.; Kobrick, M.</p> <p>2001-12-01</p> <p>The Shuttle Radar <span class="hlt">Topography</span> Mission (SRTM), which flew successfully aboard Endeavour in February 2000, is a cooperative project between NASA, the National Imagery and Mapping Agency, and the German and Italian Space Agencies. The mission was designed to use a single-pass radar interferometer to produce a digital elevation model of the Earth's land surface between about 60 degrees north and 56 degrees south latitude. The DEM will have 30 m horizontal resolution and better than 15 m vertical errors. Two ortho-rectified C-band image mosaics are also planned. Data processing will be completed by the end of 2002. SRTM used a modification of the radar instrument that comprised the Spaceborne Radar Laboratory that flew twice on the Shuttle Endeavour in 1994. To collect the interferometric data, a 60 m mast, additional C-band antenna, and improved tracking and navigation devices were added. A second X-band antenna was also added by the German Space Agency, and produced higher resolution topographic measurements in strips nested within the full, C-band coverage. First results indicate that the radars and ancillary instruments worked very well. Data played back to the ground during the flight were processed to DEMs and products released hours after acquisition. An extensive program for calibration and verification of the SRTM data is now underway. When complete later this year, systematic processing of the data will begin, with final products emerging a continent at a time. Products will be transferred to the US Geological Survey's EROS Data Center for civilian archive and distribution. NIMA will handle Department of Defense distribution. * Work performed under contract to NASA.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_12 --> <div id="page_13" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="241"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFMIN31C1015M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFMIN31C1015M"><span id="translatedtitle">The Glacier and Land Ice Surface <span class="hlt">Topography</span> Interferometer: An Airborne Proof-of-concept Mapping Sensor</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Moller, D.; Hensley, S.; Chuang, C.; Fisher, C.; Muellerschoen, R.; Milligan, L.; Sadowy, G.; Rignot, E. J.</p> <p>2009-12-01</p> <p>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 by integrating a Ka-band single-pass interferometric synthetic radar on the NASA Dryden Gulfstream III for a coordinated deployment. Although the technique of using radar interferometry for mapping terrain has been demonstrated before, this is the first such application at millimeter-wave frequencies. This proof-of-concept demonstration was motivated by the Glacier and Land Ice Surface <span class="hlt">Topography</span> Interferometer (GLISTIN) Instrument Incubator Program and furthermore, highly leveraged existing ESTO hardware and software assets (the Unmanned Airborne Vehicle Synthetic Aperture Radar (UAVSAR) and processor and the PR2 (precipitation radar 2) RF assembly and power amplifier). Initial Ka-band test flights occurred in March and April of 2009 followed by the Greenland deployment. 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. This penetration will be characterized as part of this program and is expected to vary as a function of snow wetness and radar incidence angle. To evaluate this, we flew a coordinated collection with the NASA Wallops Airborne Topographic Mapper on a transect from Greenland’s Summit its West coast. This flight included two field calibration sites at Colorado Institute for Research in Environmental Science’s Swiss Camp and the National Science Foundation’s Summit station. Additional collections entailed flying a grid over Jakobshavn glacier which were repeated after 6 days to reveal surface <span class="hlt">dynamics</span>. In this time frame we were able to observe horizontal motion of over 1km on the glacier. While developed for</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013JGRE..118..908B&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013JGRE..118..908B&link_type=ABSTRACT"><span id="translatedtitle">Convection-driven compaction as a possible origin of Enceladus's long wavelength <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Besserer, J.; Nimmo, F.; Roberts, J. H.; Pappalardo, R. T.</p> <p>2013-05-01</p> <p>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 <span class="hlt">dynamic</span> <span class="hlt">topography</span>, it can potentially leave a permanent record of ancient convective processes in the shallow lithospheres of icy satellites.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19980018849','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19980018849"><span id="translatedtitle"><span class="hlt">Topography</span> of the Moon from the Clementine Lidar</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Smith, David E.; Zuber, Maria T.; Neumann, Gregory A.; Lemoine, Frank G.</p> <p>1997-01-01</p> <p>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 <span class="hlt">Topography</span> Model 2 (GLTM 2). This topographic field has an <span class="hlt">absolute</span> 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 <span class="hlt">topography</span> 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 <span class="hlt">topography</span> 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 <span class="hlt">topography</span> 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</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1815003A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1815003A"><span id="translatedtitle">The influence of deep mantle heterogeneity on the rhythms and scales of surface <span class="hlt">topography</span> evolution</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Arnould, Maëlis; Coltice, Nicolas; Flament, Nicolas</p> <p>2016-04-01</p> <p>Earth's surface, the interface between external processes and internal <span class="hlt">dynamics</span> (lithosphere motions and mantle convection), is continuously reorganised. A large part of Earth's <span class="hlt">topography</span> is generated by mantle motions and lithospheric stresses [1], which impacts for instance the global sea-level, the <span class="hlt">dynamics</span> of sedimentary basins and the geoid. Studying how surface <span class="hlt">topography</span> evolves in both space and time thus not only provides information on the rhythms and scales of evolution of those processes, but would also be a tool for the study of the mantle motions and properties from which it originates [2]. In this study, we propose to characterise the spatial and temporal scales of evolution of surface <span class="hlt">topography</span> in 2D spherical annulus numerical models of mantle convection developing a plate-like behaviour. We use the geodynamical code StagYY [3] to first determine a mantle convection regime generating a surface <span class="hlt">topography</span> with Earth-like amplitudes and realistic mantle <span class="hlt">dynamics</span> at first order (e.g. high Rayleigh number, reasonable lithosphere thickness, pseudo-plastic lithosphere rheology generating plate tectonics). We then use this convection regime to investigate how the presence of stable deep-rooted thermochemical heterogeneities influence the rhythms of evolution of surface <span class="hlt">topography</span>. We analyse our results to identify how the timescales of evolution are connected with the lengthscales of <span class="hlt">topography</span>, in light of the tectonic histories produced by the models. References: [1] M. Gurnis, Long-term controls of eustatic and epeirogenic motions by mantle convection, GSA Today, 2(7):141-157, 1992. [2] B.H. Hager, R.W. Clayton, M.A. Richards, R.P. Comer, and A.M. Dziewonski, Lower mantle heterogeneity, <span class="hlt">dynamic</span> <span class="hlt">topography</span> and the geoid, Nature, 313:541-545, 1985. [3] J.W. Hernlund and P.J. Tackley, Modeling mantle convection in the spherical annulus, Phys. Earth Planet. Interiors, 171(1):48-54, 2008.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1031324','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1031324"><span id="translatedtitle">Enhanced Characterization of Niobium Surface <span class="hlt">Topography</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Chen Xu, Hui Tian, Charles Reece, Michael Kelley</p> <p>2011-12-01</p> <p>Surface <span class="hlt">topography</span> characterization is a continuing issue for the Superconducting Radio Frequency (SRF) particle accelerator community. Efforts are underway to both to improve surface <span class="hlt">topography</span>, and its characterization and analysis using various techniques. In measurement of <span class="hlt">topography</span>, Power Spectral Density (PSD) is a promising method to quantify typical surface parameters and develop scale-specific interpretations. PSD can also be used to indicate how chemical processes modifiesy the roughnesstopography at different scales. However, generating an accurate and meaningful topographic PSD of an SRF surface requires careful analysis and optimization. In this report, polycrystalline surfaces with different process histories are sampled with AFM and stylus/white light interferometer profilometryers and analyzed to indicate trace <span class="hlt">topography</span> evolution at different scales. evolving during etching or polishing. Moreover, Aan optimized PSD analysis protocol will be offered to serve the SRF surface characterization needs is presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMEP52A..07M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMEP52A..07M"><span id="translatedtitle">Cenozoic migration of <span class="hlt">topography</span> in the North American Cordillera</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mix, H. T.; Mulch, A.; Chamberlain, C. P.</p> <p>2010-12-01</p> <p>Continental <span class="hlt">topography</span> is the result of complex interactions among mantle convection, continental <span class="hlt">dynamics</span>, as well as climatic and erosional processes. Therefore, topographic evolution of mountain belts and continental interiors reflects directly upon the coupling between mantle and surface processes. It has recently been proposed that the modern <span class="hlt">topography</span> of western North America is partly controlled by the removal of the subducting Farallon Plate and replacement of lithospheric mantle by hot asthenosphere, creating surface uplift of the Colorado Plateau, the southwestern United States and northern Mexico, while concomitant subsidence characterizes the central United States. How the <span class="hlt">topography</span> of the Cenozoic North American Cordillera evolved in the past is largely unknown, yet currently debated tectonic models each have a predictable topographic response. We examined Cenozoic surface uplift patterns of western North America based on a record of ~3000 stable isotope proxy data. This data set is consistent with Eocene north to south surface uplift in the Cordillera, culminating in the assembly of an Eocene-Oligocene highland 3-4 km in elevation. The diachronous record of surface uplift and associated magmatism further supports tectonic models calling for the convective removal of mantle lithosphere or removal of the Farallon slab by buckling along an east-west axis. The Eocene-Oligocene development of similar-to-present day rainout patterns along the flanks of the Cordilleran orogen is therefore unlikely to be the result of late Mesozoic crustal thickening and associated development of an Andean-style Altiplano.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016JCAP...08..060V&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016JCAP...08..060V&link_type=ABSTRACT"><span id="translatedtitle">Cosmology with negative <span class="hlt">absolute</span> temperatures</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vieira, J. P. P.; Byrnes, Christian T.; Lewis, Antony</p> <p>2016-08-01</p> <p>Negative <span class="hlt">absolute</span> temperatures (NAT) are an exotic thermodynamical consequence of quantum physics which has been known since the 1950's (having been achieved in the lab on a number of occasions). Recently, the work of Braun et al. [1] has rekindled interest in negative temperatures and hinted at a possibility of using NAT systems in the lab as dark energy analogues. This paper goes one step further, looking into the cosmological consequences of the existence of a NAT component in the Universe. NAT-dominated expanding Universes experience a borderline phantom expansion (w < ‑1) with no Big Rip, and their contracting counterparts are forced to bounce after the energy density becomes sufficiently large. Both scenarios might be used to solve horizon and flatness problems analogously to standard inflation and bouncing cosmologies. We discuss the difficulties in obtaining and ending a NAT-dominated epoch, and possible ways of obtaining density perturbations with an acceptable spectrum.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011PhDT.......154L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011PhDT.......154L"><span id="translatedtitle">Corneal <span class="hlt">topography</span> measurements for biometric applications</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lewis, Nathan D.</p> <p></p> <p>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 <span class="hlt">topography</span> 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 <span class="hlt">topography</span> measured. Human subject <span class="hlt">topography</span> 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. <span class="hlt">Topography</span> data was collected from 59 subjects and modeled using Zernike polynomials, which provide for a simple method of compressing <span class="hlt">topography</span> 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 <span class="hlt">topography</span> measurements. Reasonably accurate results, between three to eight percent simultaneous false match and false non-match rates, were achieved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JGRD..117.3112H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JGRD..117.3112H"><span id="translatedtitle">Shortwave radiation parameterization scheme for subgrid <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Helbig, N.; LöWe, H.</p> <p>2012-02-01</p> <p><span class="hlt">Topography</span> 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 <span class="hlt">topography</span> 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 <span class="hlt">topographies</span> we used a large ensemble of simulated <span class="hlt">topographies</span> 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 <span class="hlt">topographies</span> from Switzerland and the United States were analyzed and Gaussian statistics were found to best approximate real <span class="hlt">topographies</span>. 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014E%26PSL.408..362H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014E%26PSL.408..362H"><span id="translatedtitle">Evaluating Marie Byrd Land stability using an improved basal <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Holschuh, N.; Pollard, D.; Alley, R. B.; Anandakrishnan, S.</p> <p>2014-12-01</p> <p>Prior understanding of the ice-sheet setting in Marie Byrd Land (MBL) was derived primarily from geologic and geochemical studies of the current nunataks, with very few geophysical surveys imaging the ice covered regions. The geologic context suggested that the ice rests on a broad regional high, in contrast to the deep basins and trenches that characterize the majority of West Antarctica. This assumed <span class="hlt">topography</span> would favor long-term stability for the West Antarctic Ice Sheet (WAIS) in MBL. Airborne geophysical data collected in 2009 reveal a much deeper bed than previously estimated, including a significant trough underlying DeVicq Glacier and evidence for extensive glacial erosion. Using these data, we produce a new map of subglacial <span class="hlt">topography</span>, with which we model the sensitivity of WAIS to a warming ocean using the ice-sheet model of Pollard and DeConto (2012b). We compare the results to estimates of ice loss during WAIS collapse using the previously defined subglacial <span class="hlt">topography</span>, to determine the impact of the newly discovered subglacial features. Our results indicate that the topographic changes are not sufficient to destabilize the northern margin of MBL currently feeding the Getz Ice Shelf; the majority of ice loss occurs from flow toward the Siple Coast. However, despite only slight <span class="hlt">dynamic</span> differences, using the new bed as a boundary condition results in an additional 8 cm of sea-level rise during major glacial retreat, an increase of just over 2%. Precise estimation of past and future ice retreat, as well as a complete understanding of the geologic history of the region, will require a higher resolution picture of the bed <span class="hlt">topography</span> around the Executive Committee mountains.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016ClDy...46.2535J&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016ClDy...46.2535J&link_type=ABSTRACT"><span id="translatedtitle">Influence of <span class="hlt">topography</span> on tropical African vegetation coverage</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jung, Gerlinde; Prange, Matthias; Schulz, Michael</p> <p>2016-04-01</p> <p>Hominid evolution in the late Miocene has long been hypothesized to be linked to the retreat of the tropical rainforest in Africa. One cause for the climatic and vegetation change often considered was uplift of Africa, but also uplift of the Himalaya and the Tibetan Plateau was suggested to have impacted rainfall distribution over Africa. Recent proxy data suggest that in East Africa open grassland habitats were available to the common ancestors of hominins and apes long before their divergence and do not find evidence for a closed rainforest in the late Miocene. We used the coupled global general circulation model CCSM3 including an interactively coupled <span class="hlt">dynamic</span> vegetation module to investigate the impact of <span class="hlt">topography</span> on African hydro-climate and vegetation. We performed sensitivity experiments altering elevations of the Himalaya and the Tibetan Plateau as well as of East and Southern Africa. The simulations confirm the dominant impact of African <span class="hlt">topography</span> for climate and vegetation development of the African tropics. Only a weak influence of prescribed Asian uplift on African climate could be detected. The model simulations show that rainforest coverage of Central Africa is strongly determined by the presence of elevated African <span class="hlt">topography</span>. In East Africa, despite wetter conditions with lowered African <span class="hlt">topography</span>, the conditions were not favorable enough to maintain a closed rainforest. A discussion of the results with respect to other model studies indicates a minor importance of vegetation-atmosphere or ocean-atmosphere feedbacks and a large dependence of the simulated vegetation response on the land surface/vegetation model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFM.C31E0569M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFM.C31E0569M"><span id="translatedtitle">Satellite Altimetric Mappings of Arctic Sea Surface <span class="hlt">Topography</span>: An Evaluation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>McAdoo, D. C.; Farrell, S. L.; Laxon, S. W.; Zwally, H. J.; Yi, D.; Coakley, B.; Cochran, J. R.</p> <p>2008-12-01</p> <p>Increasingly precise mappings of sea surface <span class="hlt">topography</span> (SST) in the Arctic Ocean are being derived from near-polar satellite altimeters such as the laser system - Geoscience Laser Altimeter System (GLAS) - onboard NASA's ICESat and the radar systems onboard ESA's ERS-2 and Envisat. These mappings of sea surface <span class="hlt">topography</span> (SST) have important oceanographic and geodetic applications. For example, because the geoid does conform closely to sea surface <span class="hlt">topography</span> we can use altimetric SST measurements to estimate gravity (e.g., see the ARCtic Satellite-only (ARCS) field, McAdoo et al. 2008) particularly in regions lacking "true" surface gravity observations. Also, by differencing mappings of mean SST with a gravimetric geoid - particularly a geoid underpinned by a GRACE mean field model - we can estimate the <span class="hlt">dynamic</span> ocean <span class="hlt">topography</span> (DOT) and circulation of the Arctic Ocean. However, accurate estimates of DOT (e.g. accuracies better than a decimeter) require that we have very precise knowledge of the geoid and mean SST. Comparing a mean SST derived from ICESat/GLAS data spanning several years with a corresponding mean SST derived from ERS-2 data reveals short- wavelength differences or discrepancies of order 40 - 60 cm in certain areas of the Arctic Ocean such as the Chukchi Borderland. In order to attribute a portion of these discrepancies to laser or radar altimeter measurement error, we convert these mean SST fields to equivalent gravity fields and compare with gravity observations from several of the unclassified SCICEX/U.S. Navy submarine cruises (Edwards and Coakley, 2003; http://www.ldeo.columbia.edu/res/pi/SCICEX/ ). This comparison enables us to quantify short-wavelength errors in both laser and radar altimetric mean SST models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMPP33B1231C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMPP33B1231C"><span id="translatedtitle">Reconstructing Pliocene coastlines, <span class="hlt">topography</span> and bathymetry: A geodynamic perspective</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chandan, D.; Peltier, W. R.</p> <p>2014-12-01</p> <p>The middle Pliocene period (~3.3-3.0 Mya) was characterized by warm temperatures (2-3℃ higher) and high carbon-dioxide (~400 ppmv) concentrations which has led to its recognition as a possible analogue for the future climate. Under the auspices of the Pliocene Modeling and Intercomparison Project (PlioMIP), general circulation models (GCM's) are being employed to simulate mid-Pliocene climate to better understand the biases in these models, which are presently used to make future climate predictions. Necessary boundary conditions for these simulations — land mask, <span class="hlt">topography</span>, surface albedo and vegetation cover are being provided by the Pliocene Research, Interpretation and Synoptic Mapping (PRISM) project. Bathymetry, which is not part of the PRISM supplied dataset has been adjusted by raising the sea-level by an assumed constant eustatic amount. At present the PRISM land mask, <span class="hlt">topography</span> and bathymetry reconstructions do not incorporate the gravitationally self consistent changes that would be required to account for the mass loss from the Greenland and Antarctic ice-sheets that produced the assumed rise in eustatic sea level. The effects of <span class="hlt">dynamic</span> <span class="hlt">topography</span> induced corrections, due to the action of the mantle convection process, have also been neglected.The influence of these corrections on the predictions of Pliocene climate using modern GCM's remains unexplored. The continuing failure of these models to simulate proxy inferred levels of warming in high-latitude [Dowsett et al., 2013, Sci. Rep.] regions where the magnitude of the required corrections are expected to be largest make it especially important that their impact be assessed. Here, we present the results from a preliminary of the required modifications to the boundary condition data sets.We compute the gravitationally self consistent corrections using the viscoelastic theory of global, glacial isostatic adjustment and relative sea level history for a spherically symmetric Earth model. <span class="hlt">Dynamic</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.C31A0581C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.C31A0581C"><span id="translatedtitle">The relationship between ice velocity and bed <span class="hlt">topography</span> on Byrd Glacier, Antarctica</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Child, S.; Stearns, L. A.; Purdon, K.; Li, J.; Rodriguez-Morales, F.; Crowe, R.; Gomez-Garcia, D.</p> <p>2012-12-01</p> <p>Bed <span class="hlt">topography</span> controls the pattern and magnitude of ice velocity, far into the catchment basin of many Antarctic outlet glaciers. Predictive models of glacier <span class="hlt">dynamics</span> and ice sheet mass balance rely on well-prescribed bed <span class="hlt">topography</span>, but in many regions bed <span class="hlt">topography</span> is largely unknown. This particular study investigates the relationship between bed and surface <span class="hlt">topography</span> and ice velocity in the catchment basin and trunk of Byrd Glacier. Byrd Glacier drains ~19 % of the area of the East Antarctic Ice Sheet (1,070,400 km2), and has the potential to play a significant role in the ice sheet's total mass balance. In 2011/2012, the Center for Remote Sensing of Ice Sheets (CReSIS) collected airborne radar data over Byrd Glacier. These new measurements of bed <span class="hlt">topography</span>, along with updated surface digital elevation models (DEMs) and basin-wide ice velocity maps, are used to investigate the flow <span class="hlt">dynamics</span> of Byrd Glacier with improved accuracy. Surface DEMs are derived from new high-resolution WorldView imagery; ice velocity is derived from repeat visible imagery, coupled with InSAR results (Rignot et al., 2011). Results exhibit relatively smooth depressions surrounding the inferred subglacial lakes, ~200 km upflow of the grounding line on Byrd Glacier (Stearns et al., 2008). Downflow of the subglacial lakes is a complex pattern of hills and valleys as ice enters the glacier trunk. At the mouth of the trunk is a large overdeepening (~2500 m) that coincides with faster ice flow. We use along- and across-flow radar profiles to perform detailed comparisons of ice velocity, bed <span class="hlt">topography</span> and surface <span class="hlt">topography</span> throughout the Byrd Glacier region. Gridded products are used to complete an updated force balance assessment. These results provide us with a better understanding of Byrd Glacier's flow <span class="hlt">dynamics</span> and sensitivity to external perturbations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AAS...210.8602L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AAS...210.8602L"><span id="translatedtitle">Improving HST Pointing & <span class="hlt">Absolute</span> Astrometry</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lallo, Matthew; Nelan, E.; Kimmer, E.; Cox, C.; Casertano, S.</p> <p>2007-05-01</p> <p>Accurate <span class="hlt">absolute</span> astrometry is becoming increasingly important in an era of multi-mission archives and virtual observatories. Hubble Space Telescope's (HST's) Guidestar Catalog II (GSC2) has reduced coordinate error to around 0.25 arcsecond, a factor 2 or more compared with GSC1. With this reduced catalog error, special attention must be given to calibrate and maintain the Fine Guidance Sensors (FGSs) and Science Instruments (SIs) alignments in HST to a level well below this in order to ensure that the accuracy of science product's astrometry keywords and target positioning are limited only by the catalog errors. After HST Servicing Mission 4, such calibrations' improvement in "blind" pointing accuracy will allow for more efficient COS acquisitions. Multiple SIs and FGSs each have their own footprints in the spatially shared HST focal plane. It is the small changes over time in primarily the whole-body positions & orientations of these instruments & guiders relative to one another that is addressed by this work. We describe the HST Cycle 15 program CAL/OTA 11021 which, along with future variants of it, determines and maintains positions and orientations of the SIs and FGSs to better than 50 milli- arcseconds and 0.04 to 0.004 degrees of roll, putting errors associated with the alignment sufficiently below GSC2 errors. We present recent alignment results and assess their errors, illustrate trends, and describe where and how the observer sees benefit from these calibrations when using HST.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/3777908','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/3777908"><span id="translatedtitle"><span class="hlt">Absolute</span> oral bioavailability of ciprofloxacin.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Drusano, G L; Standiford, H C; Plaisance, K; Forrest, A; Leslie, J; Caldwell, J</p> <p>1986-09-01</p> <p>We evaluated the <span class="hlt">absolute</span> bioavailability of ciprofloxacin, a new quinoline carboxylic acid, in 12 healthy male volunteers. Doses of 200 mg were given to each of the volunteers in a randomized, crossover manner 1 week apart orally and as a 10-min intravenous infusion. Half-lives (mean +/- standard deviation) for the intravenous and oral administration arms were 4.2 +/- 0.77 and 4.11 +/- 0.74 h, respectively. The serum clearance rate averaged 28.5 +/- 4.7 liters/h per 1.73 m2 for the intravenous administration arm. The renal clearance rate accounted for approximately 60% of the corresponding serum clearance rate and was 16.9 +/- 3.0 liters/h per 1.73 m2 for the intravenous arm and 17.0 +/- 2.86 liters/h per 1.73 m2 for the oral administration arm. Absorption was rapid, with peak concentrations in serum occurring at 0.71 +/- 0.15 h. Bioavailability, defined as the ratio of the area under the curve from 0 h to infinity for the oral to the intravenous dose, was 69 +/- 7%. We conclude that ciprofloxacin is rapidly absorbed and reliably bioavailable in these healthy volunteers. Further studies with ciprofloxacin should be undertaken in target patient populations under actual clinical circumstances. PMID:3777908</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014APS..DPPJO6008H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014APS..DPPJO6008H"><span id="translatedtitle"><span class="hlt">Absolute</span> Instability in Coupled-Cavity TWTs</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hung, D. M. H.; Rittersdorf, I. M.; Zhang, Peng; Lau, Y. Y.; Simon, D. H.; Gilgenbach, R. M.; Chernin, D.; Antonsen, T. M., Jr.</p> <p>2014-10-01</p> <p>This paper will present results of our analysis of <span class="hlt">absolute</span> instability in a coupled-cavity traveling wave tube (TWT). The structure mode at the lower and upper band edges are respectively approximated by a hyperbola in the (omega, k) plane. When the Briggs-Bers criterion is applied, a threshold current for onset of <span class="hlt">absolute</span> instability is observed at the upper band edge, but not the lower band edge. The nonexistence of <span class="hlt">absolute</span> instability at the lower band edge is mathematically similar to the nonexistence of <span class="hlt">absolute</span> instability that we recently demonstrated for a dielectric TWT. The existence of <span class="hlt">absolute</span> instability at the upper band edge is mathematically similar to the existence of <span class="hlt">absolute</span> instability in a gyroton traveling wave amplifier. These interesting observations will be discussed, and the practical implications will be explored. This work was supported by AFOSR, ONR, and L-3 Communications Electron Devices.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016OcMod.102...55Z&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016OcMod.102...55Z&link_type=ABSTRACT"><span id="translatedtitle">On the observability of bottom <span class="hlt">topography</span> from measurements of tidal sea surface height</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zaron, Edward D.</p> <p>2016-06-01</p> <p>The question of whether features of the ocean bottom <span class="hlt">topography</span> can be identified from measurements of water level is investigated using a simplified one-dimensional barotropic model. Because of the nonlinear dependence of the sea surface height on the water depth, a linearized analysis is performed concerning the identification of a Gaussian bump within two specific depth profiles, (1) a constant depth domain, and, (2) a constant depth domain adjoining a near-resonant continental shelf. Observability is quantified by examining the estimation error in a series of identical-twin experiments varying data density, tide wavelength, assumed (versus actual) topographic correlation scale, and friction. For measurements of sea surface height that resolve the scale of the topographic perturbation, the fractional error in the bottom <span class="hlt">topography</span> is approximately a factor of 10 larger than the fractional error of the sea surface height. Domain-scale and shelf-scale resonances may lead to inaccurate <span class="hlt">topography</span> estimates due to a reduction in the effective number of degrees of freedom in the <span class="hlt">dynamics</span>, and the amplification of nonlinearity. A realizability condition for the variance of the <span class="hlt">topography</span> error in the limit of zero bottom depth is proposed which is interpreted as a bound on the fractional error of the <span class="hlt">topography</span>. Appropriately designed spatial covariance models partly ameliorate the negative impact of shelf-scale near-resonance, and highlight the importance of spatial covariance modeling for bottom <span class="hlt">topography</span> estimation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4460076','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4460076"><span id="translatedtitle">Electronic Cigarette <span class="hlt">Topography</span> in the Natural Environment</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Morabito, P. N.; Roundtree, K. A.</p> <p>2015-01-01</p> <p>This paper presents the results of a clinical, observational, descriptive study to quantify the use patterns of electronic cigarette users in their natural environment. Previously published work regarding puff <span class="hlt">topography</span> has been widely indirect in nature, and qualitative rather than quantitative, with the exception of three studies conducted in a laboratory environment for limited amounts of time. The current study quantifies the variation in puffing behaviors among users as well as the variation for a given user throughout the course of a day. Puff <span class="hlt">topography</span> characteristics computed for each puffing session by each subject include the number of subject puffs per puffing session, the mean puff duration per session, the mean puff flow rate per session, the mean puff volume per session, and the cumulative puff volume per session. The same puff <span class="hlt">topography</span> characteristics are computed across all puffing sessions by each single subject and across all subjects in the study cohort. Results indicate significant inter-subject variability with regard to puffing <span class="hlt">topography</span>, suggesting that a range of representative puffing <span class="hlt">topography</span> patterns should be used to drive machine-puffed electronic cigarette aerosol evaluation systems. PMID:26053075</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015E%26PSL.430....9F&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015E%26PSL.430....9F&link_type=ABSTRACT"><span id="translatedtitle">Influence of subduction history on South American <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Flament, Nicolas; Gurnis, Michael; Müller, R. Dietmar; Bower, Dan J.; Husson, Laurent</p> <p>2015-11-01</p> <p>The Cenozoic evolution of South American <span class="hlt">topography</span> is marked by episodes of large-scale uplift and subsidence not readily explained by lithospheric deformation. The drying up of the inland Pebas system, the drainage reversal of the Amazon river, the uplift of the Sierras Pampeanas and the uplift of Patagonia have all been linked to the evolution of mantle flow since the Miocene in separate studies. Here we investigate the evolution of long-wavelength South American <span class="hlt">topography</span> as a function of subduction history in a time-dependent global geodynamic model. This model is shown to be consistent with these inferred changes, as well as with the migration of the Chaco foreland basin depocentre, that we partly attribute to the inboard migration of subduction resulting from Andean mountain building. We suggest that the history of subduction along South America has had an important influence on the evolution of the <span class="hlt">topography</span> of the continent because time-dependent mantle flow models are consistent with the history of vertical motions as constrained by the geological record at four distant areas over a whole continent. Testing alternative subduction scenarios reveals flat slab segments are necessary to reconcile inferred Miocene shorelines with a simple model paleogeography. As recently suggested, we find that the flattening of a subduction zone results in <span class="hlt">dynamic</span> uplift between the leading edge of the flat slab segment and the trench, and in a wave of <span class="hlt">dynamic</span> subsidence associated with the inboard migration of the leading edge of flat subduction. For example, the flattening of the Peruvian subduction contributed to the demise of Pebas shallow-water sedimentation, while continental-scale tilting also contributed to the drainage reversal of the Amazon River. The best correlation to P-wave tomography models for the Peruvian flat slab segment is obtained for a case when the asthenosphere, here considered to be 150 km thick and 10 times less viscous than the upper mantle, is</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_13 --> <div id="page_14" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="261"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015GGG....16.1378P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015GGG....16.1378P"><span id="translatedtitle">Development of <span class="hlt">topography</span> in 3-D continental-collision models</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pusok, A. E.; Kaus, Boris J. P.</p> <p>2015-05-01</p> <p>Understanding the formation and evolution of high mountain belts, such as the Himalayas and the adjacent Tibetan Plateau, has been the focus of many tectonic and numerical models. Here we employ 3-D numerical simulations to investigate the role that subduction, collision, and indentation play on lithosphere <span class="hlt">dynamics</span> at convergent margins, and to analyze the conditions under which large topographic plateaus can form in an integrated lithospheric and upper mantle-scale model. Distinct <span class="hlt">dynamics</span> are obtained for the oceanic subduction side (trench retreat, slab rollback) and the continental-collision side (trench advance, slab detachment, topographic uplift, lateral extrusion). We show that slab pull alone is insufficient to generate high <span class="hlt">topography</span> in the upper plate, and that external forcing and the presence of strong blocks such as the Tarim Basin are necessary to create and shape anomalously high topographic fronts and plateaus. Moreover, scaling is used to predict four different modes of surface expression in continental-collision models: (I) low-amplitude homogeneous shortening, (II) high-amplitude homogeneous shortening, (III) Alpine-type <span class="hlt">topography</span> with topographic front and low plateau, and (IV) Tibet-Himalaya-type <span class="hlt">topography</span> with topographic front and high plateau. Results of semianalytical models suggest that the Argand number governs the formation of high topographic fronts, while the amplitude of plateaus is controlled by the initial buoyancy ratio of the upper plate. Applying these results to natural examples, we show that the Alps belong to regime (III), the Himalaya-Tibet to regime (IV), whereas the Andes-Altiplano fall at the boundary between regimes (III) and (IV).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APS..DFDL29008M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..DFDL29008M"><span id="translatedtitle">Experiments on <span class="hlt">topographies</span> lacking tidal conversion</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Maas, Leo; Paci, Alexandre; Yuan, Bing</p> <p>2015-11-01</p> <p>In a stratified sea, internal tides are supposedly generated when the tide passes over irregular <span class="hlt">topography</span>. It has been shown that for any given frequency in the internal wave band there are an infinite number of exceptions to this rule of thumb. This ``stealth-like'' property of the <span class="hlt">topography</span> is due to a subtle annihilation of the internal waves generated during the surface tide's passage over the irregular bottom. We here demonstrate this in a lab-experiment. However, for any such <span class="hlt">topography</span>, subsequently changing the surface tide's frequency does lead to tidal conversion. The upshot of this is that a tidal wave passing over an irregular bottom is for a substantial part trapped to this irregularity, and only partly converted into freely propagating internal tides. Financially supported by the European Community's 7th Framework Programme HYDRALAB IV.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ISPAn.II5..301H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ISPAn.II5..301H"><span id="translatedtitle"><span class="hlt">Topography</span> Restoration of Historic City Research</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>ho, L. Sung; soo, H. Dong</p> <p>2015-08-01</p> <p>The preservation of historic cities requires a balance between conservation and development because the urban structures of the old and new city are interwoven on same space. Existing restoration plans rely on old records and excavation reports and are based on the present <span class="hlt">topography</span>. However, historic cities have undergone significant natural and anthropogenic topographic changes such as alluvial sediment accumulation and uneven terrain construction. Therefore, considering only the present <span class="hlt">topography</span> is misleading. Thus, to understand a historic city's structure more appropriately, it is necessary to comprehend the ancient geographic environment. This study provides an analysis and GIS visualization of the ancient <span class="hlt">topography</span> of a historic city, Sabi capital city of the Baekje Dynasty, which collapsed 1,500 years ago.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003OptLE..40..143M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003OptLE..40..143M"><span id="translatedtitle">Moiré <span class="hlt">topography</span> in odontology</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Moreno Yeras, A.</p> <p>2003-07-01</p> <p>For several decades, measurement of optical techniques has been used in different branches of science and technology. One of these techniques is the so-called moiré <span class="hlt">topography</span> (MT) that enables the accurate measurement of different parts of the human body <span class="hlt">topography</span>. This investigation presents the measurement of <span class="hlt">topographies</span> of teeth and gums using an automated system of shadow moiré and the phase shift method in an original way. The fringe patterns used to compute the shape and the shape matrix itself are presented in the article. The phase shift method ensures precisions up to the order of microns. Advantages and disadvantages of using the MT are included. Besides, some positive and negative aspects concerned with the implementation of this technique in odontology are shown in the article.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APS..DFD.M8005L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..DFD.M8005L"><span id="translatedtitle">Transient coating of substrates with variable <span class="hlt">topography</span> by viscous films</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lampropoulos, Nikos; Dimakopoulos, Yiannis; Tsamopoulos, John</p> <p>2015-11-01</p> <p>We study the transient coating of substrates exhibiting orthogonal trenches. We use the VoF method via OpenFOAM to solve the transient NS eqs on an unstructured grid, which <span class="hlt">dynamically</span> undergoes local refinement around the interfaces. An Euler implicit method is used with adjustable time-step. The computational cost is reduced by parallel execution via MPI. Completely different wetting patterns result depending on the 3 dimensions of the <span class="hlt">topography</span>, the capillary and Reynolds numbers and the <span class="hlt">dynamic</span> contact angle. On one hand, continuous coating can be achieved in which the thin film of fluid wets the entire trench, while a steady flow is established upstream and downstream the <span class="hlt">topography</span>. This is the desirable pattern in coating microelectronic devices for their protection and planarization. The other extreme possibility is that the film completely bypasses the trench, entrapping air inside it. This pattern reduces the drag coefficient on the film and, therefore, it is desirable in super-hydrophobic surfaces for microfluidic applications. Between these two extremes, a large variety of patterns exists in which the film partially wets the trench forming an air inclusion all along its bottom surface or its upstream or downstream inner corners or the film may breakup periodically. We produce comprehensive maps of film configurations covering a wide range of parameter values. GSRT of Greece via the program ``Excellence,'' Grant 1918.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011PhDT........79V&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011PhDT........79V&link_type=ABSTRACT"><span id="translatedtitle">Effects of patterned <span class="hlt">topography</span> on biofilm formation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vasudevan, Ravikumar</p> <p>2011-12-01</p> <p>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 <span class="hlt">topography</span> interaction studies and Ulva linza spore studies, topographical surfaces were suggested as a benign control method for biofilm formation. However, <span class="hlt">topographies</span> tested so far have not included a systematic variation of size across basic <span class="hlt">topography</span> shapes. In this study patterned <span class="hlt">topography</span> 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 <span class="hlt">topography</span> 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 <span class="hlt">topography</span> characterizations. This was done based on antibiotic susceptibility evaluation and also based on gene expression analysis. Although orientational effects occur, phenotypically no difference</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/21811317','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21811317"><span id="translatedtitle">Noninterferometric <span class="hlt">topography</span> measurements of fast moving surfaces.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Pinhasi, Shirly Vinikman; Eliezer, Shalom; Glam, Benny; Appelbaum, Gabi; Bakshi, Lior</p> <p>2011-08-01</p> <p>The <span class="hlt">topography</span> 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 <span class="hlt">topographies</span> of a moving projectile and the free surface of a shocked target were recovered. PMID:21811317</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=origin+AND+algebra&pg=3&id=EJ458199','ERIC'); return false;" href="http://eric.ed.gov/?q=origin+AND+algebra&pg=3&id=EJ458199"><span id="translatedtitle">Inequalities, <span class="hlt">Absolute</span> Value, and Logical Connectives.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Parish, Charles R.</p> <p>1992-01-01</p> <p>Presents an approach to the concept of <span class="hlt">absolute</span> value that alleviates students' problems with the traditional definition and the use of logical connectives in solving related problems. Uses a model that maps numbers from a horizontal number line to a vertical ray originating from the origin. Provides examples solving <span class="hlt">absolute</span> value equations and…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20060044287&hterms=metrology&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dmetrology','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20060044287&hterms=metrology&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dmetrology"><span id="translatedtitle"><span class="hlt">Absolute</span> optical metrology : nanometers to kilometers</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Dubovitsky, Serge; Lay, O. P.; Peters, R. D.; Liebe, C. C.</p> <p>2005-01-01</p> <p>We provide and overview of the developments in the field of high-accuracy <span class="hlt">absolute</span> optical metrology with emphasis on space-based applications. Specific work on the Modulation Sideband Technology for <span class="hlt">Absolute</span> Ranging (MSTAR) sensor is described along with novel applications of the sensor.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1261596','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1261596"><span id="translatedtitle">Monolithically integrated <span class="hlt">absolute</span> frequency comb laser system</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Wanke, Michael C.</p> <p>2016-07-12</p> <p>Rather than down-convert optical frequencies, a QCL laser system directly generates a THz frequency comb in a compact monolithically integrated chip that can be locked to an <span class="hlt">absolute</span> frequency without the need of a frequency-comb synthesizer. The monolithic, <span class="hlt">absolute</span> frequency comb can provide a THz frequency reference and tool for high-resolution broad band spectroscopy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=VALUE+AND+ABSOLUTE&pg=2&id=EJ1050985','ERIC'); return false;" href="http://eric.ed.gov/?q=VALUE+AND+ABSOLUTE&pg=2&id=EJ1050985"><span id="translatedtitle">Introducing the Mean <span class="hlt">Absolute</span> Deviation "Effect" Size</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Gorard, Stephen</p> <p>2015-01-01</p> <p>This paper revisits the use of effect sizes in the analysis of experimental and similar results, and reminds readers of the relative advantages of the mean <span class="hlt">absolute</span> deviation as a measure of variation, as opposed to the more complex standard deviation. The mean <span class="hlt">absolute</span> deviation is easier to use and understand, and more tolerant of extreme…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/EJ853800.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/EJ853800.pdf"><span id="translatedtitle">Investigating <span class="hlt">Absolute</span> Value: A Real World Application</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Kidd, Margaret; Pagni, David</p> <p>2009-01-01</p> <p>Making connections between various representations is important in mathematics. In this article, the authors discuss the numeric, algebraic, and graphical representations of sums of <span class="hlt">absolute</span> values of linear functions. The initial explanations are accessible to all students who have experience graphing and who understand that <span class="hlt">absolute</span> value simply…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=happiness&pg=7&id=EJ804151','ERIC'); return false;" href="http://eric.ed.gov/?q=happiness&pg=7&id=EJ804151"><span id="translatedtitle"><span class="hlt">Absolute</span> Income, Relative Income, and Happiness</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Ball, Richard; Chernova, Kateryna</p> <p>2008-01-01</p> <p>This paper uses data from the World Values Survey to investigate how an individual's self-reported happiness is related to (i) the level of her income in <span class="hlt">absolute</span> terms, and (ii) the level of her income relative to other people in her country. The main findings are that (i) both <span class="hlt">absolute</span> and relative income are positively and significantly…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015SuTMP...3a3001L&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015SuTMP...3a3001L&link_type=ABSTRACT"><span id="translatedtitle">Open questions in surface <span class="hlt">topography</span> measurement: a roadmap</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Leach, Richard; Evans, Christopher; He, Liangyu; Davies, Angela; Duparré, Angela; Henning, Andrew; Jones, Christopher W.; O'Connor, Daniel</p> <p>2015-03-01</p> <p> principles for statistically stationary, random surfaces. For rougher surfaces, correlations can be found experimentally for specific manufacturing processes. Improvements in computational methods encourage us to revisit light scattering as a powerful and versatile tool to investigate surface and thin film <span class="hlt">topographies</span>, potentially providing information on both <span class="hlt">topography</span> and defects over large areas at high speed. Future scattering techniques will be applied for complex film systems and for sub-surface damage measurement, but more research is required to quantify and standardise such measurements. A fundamental limitation of all <span class="hlt">topography</span> measurement systems is their finite spatial bandwidth, which limits the slopes that they can detect. The third section ‘Optical measurements of surfaces containing high slope angles’ discusses this limitation and potential methods to overcome it. In some cases, a rough surface can allow measurement of slopes outside the classical optics limit, but more research is needed to fully understand this process. The last section ‘What are the challenges for high <span class="hlt">dynamic</span> range surface measurement?’ presents the challenge facing metrologists by the use of surfaces that need measurement systems with very high spatial and temporal bandwidths, for example, those found in roll-to-roll manufacturing. High resolution, large areas and fast measurement times are needed, and these needs are unlikely to be fulfilled by developing a single all-purpose instrument. A toolbox of techniques needs to be developed which can be applied for any specific manufacturing scenario. The functional significance of surface <span class="hlt">topography</span> has been known for centuries. Mirrors are smooth. Sliding behaviour depends on roughness. We have been measuring surfaces for centuries, but we still face many challenges. New manufacturing paradigms suggest that we need to make rapid measurements online that relate to the functional performance of the surface. This first </p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SuTMP...3a3001L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SuTMP...3a3001L"><span id="translatedtitle">Open questions in surface <span class="hlt">topography</span> measurement: a roadmap</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Leach, Richard; Evans, Christopher; He, Liangyu; Davies, Angela; Duparré, Angela; Henning, Andrew; Jones, Christopher W.; O'Connor, Daniel</p> <p>2015-03-01</p> <p> principles for statistically stationary, random surfaces. For rougher surfaces, correlations can be found experimentally for specific manufacturing processes. Improvements in computational methods encourage us to revisit light scattering as a powerful and versatile tool to investigate surface and thin film <span class="hlt">topographies</span>, potentially providing information on both <span class="hlt">topography</span> and defects over large areas at high speed. Future scattering techniques will be applied for complex film systems and for sub-surface damage measurement, but more research is required to quantify and standardise such measurements. A fundamental limitation of all <span class="hlt">topography</span> measurement systems is their finite spatial bandwidth, which limits the slopes that they can detect. The third section ‘Optical measurements of surfaces containing high slope angles’ discusses this limitation and potential methods to overcome it. In some cases, a rough surface can allow measurement of slopes outside the classical optics limit, but more research is needed to fully understand this process. The last section ‘What are the challenges for high <span class="hlt">dynamic</span> range surface measurement?’ presents the challenge facing metrologists by the use of surfaces that need measurement systems with very high spatial and temporal bandwidths, for example, those found in roll-to-roll manufacturing. High resolution, large areas and fast measurement times are needed, and these needs are unlikely to be fulfilled by developing a single all-purpose instrument. A toolbox of techniques needs to be developed which can be applied for any specific manufacturing scenario. The functional significance of surface <span class="hlt">topography</span> has been known for centuries. Mirrors are smooth. Sliding behaviour depends on roughness. We have been measuring surfaces for centuries, but we still face many challenges. New manufacturing paradigms suggest that we need to make rapid measurements online that relate to the functional performance of the surface. This first </p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19840023682','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19840023682"><span id="translatedtitle">Prelaunch <span class="hlt">absolute</span> radiometric calibration of LANDSAT-4 protoflight Thematic Mapper</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Barker, J. L.; Ball, D. L.; Leung, K. C.; Walker, J. A.</p> <p>1984-01-01</p> <p>Results are summarized and analyzed from several prelaunch tests with a 122 cm integrating sphere used as part of the <span class="hlt">absolute</span> radiometric calibration experiments for the protoflight TM sensor carried on the LANDSAT-4 satellite. The calibration procedure is presented and the radiometric sensitivity of the TM is assessed. The internal calibrator and <span class="hlt">dynamic</span> range after calibration are considered. Tables show <span class="hlt">dynamic</span> range after ground processing, spectral radiance to digital number and digital number to spectral radiance values for TM bands 1, 2, 3, 4, 5, 7 and for channel 4 of band 6.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19880033615&hterms=VALUE+ABSOLUTE&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DVALUE%2BABSOLUTE','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19880033615&hterms=VALUE+ABSOLUTE&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DVALUE%2BABSOLUTE"><span id="translatedtitle"><span class="hlt">Absolute</span> instability of the Gaussian wake profile</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hultgren, Lennart S.; Aggarwal, Arun K.</p> <p>1987-01-01</p> <p>Linear parallel-flow stability theory has been used to investigate the effect of viscosity on the local <span class="hlt">absolute</span> instability of a family of wake profiles with a Gaussian velocity distribution. The type of local instability, i.e., convective or <span class="hlt">absolute</span>, is determined by the location of a branch-point singularity with zero group velocity of the complex dispersion relation for the instability waves. The effects of viscosity were found to be weak for values of the wake Reynolds number, based on the center-line velocity defect and the wake half-width, larger than about 400. <span class="hlt">Absolute</span> instability occurs only for sufficiently large values of the center-line wake defect. The critical value of this parameter increases with decreasing wake Reynolds number, thereby indicating a shrinking region of <span class="hlt">absolute</span> instability with decreasing wake Reynolds number. If backflow is not allowed, <span class="hlt">absolute</span> instability does not occur for wake Reynolds numbers smaller than about 38.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008SPIE.7106E..03N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008SPIE.7106E..03N"><span id="translatedtitle">The Ocean Surface <span class="hlt">Topography</span> Mission (OSTM)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Neeck, Steven P.; Vaze, Parag V.</p> <p>2008-10-01</p> <p>The Ocean Surface <span class="hlt">Topography</span> Mission (OSTM), also known as Jason-2, will extend into the next decade the continuous climate data record of sea surface height measurements begun in 1992 by the joint NASA/Centre National d'Etudes Spatiales (CNES) TOPEX/Poseidon mission and continued by the NASA/CNES Jason-1 mission in 2001. This multi-decadal record has already helped scientists study the issue of global sea level rise and better understand how ocean circulation and climate change are related. With OSTM, high-precision ocean altimetry has come of age. The mission will serve as a bridge to transition the collection of these measurements to the world's weather and climate forecasting agencies. The agencies will use them for short- and seasonal-to-long-range weather and climate forecasting. OSTM is designed to last at least three years. It will be placed in the same orbit (1,336 kilometers) as Jason-1 and will move along the same ground track at an inclination of 66 degrees to the equator. It will repeat its ground track every 10 days, covering 95 percent of the world's ice-free oceans. A tandem mission between Jason-1 and OSTM will be conducted to further improve tide models in coastal and shallow seas, and to better understand the <span class="hlt">dynamics</span> of ocean currents and eddies. OSTM is an international and interagency mission developed and operated as a four-party collaboration among NASA, the National Oceanic and Atmospheric Administration (NOAA), CNES, and the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT). CNES is providing the spacecraft, NASA and CNES are jointly providing the payload instruments and NASA is providing the launch vehicle. After completing the onorbit commissioning of the spacecraft, CNES will hand over operation and control of the spacecraft to NOAA. NOAA and EUMETSAT will generate the near-real-time products and distribute them to users. OSTM was launched from Vandenberg Air Force Base, California on June 20, 2008</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMOS12B..01L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMOS12B..01L"><span id="translatedtitle">Overland Tsunami Flow through Complex <span class="hlt">Topography</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lynett, P. J.; Cox, D. T.; Park, H.; Wiebe, D. M.</p> <p>2012-12-01</p> <p>As seen in numerous Japanese eyewitness videos that captured the tsunami inundation on March 11th 2011, flow interaction with the built environment is extremely complex. In addition to the entrainment of sediment and large discrete objects such as cars and ships, tsunami energy amplification due to topographic focusing was widely observed. In coastal towns and cities, this topographic focusing was due to large structures which channelled the flow to either side, often through roadways or other low-obstruction pathways. Structures in the "line-of-fire" of this channelized flow were often found to have been inflicted with relatively greater levels of damage, while the opposite was true for structures in the flow-shadow of large buildings. In this presentation, we attempt to quantify the hydrodynamic variability of flow through complex <span class="hlt">topography</span>, such as a city layout. Understanding this variability is of particular relevance to on-going engineering efforts to develop standards for tsunami design of coastal structures. A novel set of large-scale experimental data will be introduced and used to validate a depth-integrated model. The experiment was performed in the Tsunami Wave Basin at Oregon State University. Transient long wave flooding in a 1/50 scale model of the town of Seaside, Oregon was tested. Data from the experiment, including water elevations and co-located flow speeds, are used to confirm the simulated <span class="hlt">dynamics</span> in the numerical model. The model is shown to be capable of accurately reproducing the instantaneous wave elevation, velocity, and momentum flux of a long wave flooding a town. It is found that the numerical prediction is sensitive to the value of the bottom roughness coefficient. The model is then extended to look at the hydrodynamics in more detail and for other cases. Predicted momentum flux values from with structures resolved, with-out structures resolved, and with spatially variable bottom roughness will be discussed. It is found that</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMDI51A2275D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMDI51A2275D"><span id="translatedtitle">CMB <span class="hlt">topography</span> and electrical conductivity as additional constraints for the lowermost mantle thermo-chemical structure</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Deschamps, F.; Yin, Y.; Tackley, P. J.</p> <p>2013-12-01</p> <p>A variety of seismic observations, including tomographic models, indicate that the lowermost mantle is strongly heterogeneous. Seismic observations further support a thermo-chemical origin for the large scale heterogeneities. In particular, the large low-shear wave velocity provinces (LLSVP) observed by global tomographic images are better explained by a combination of thermal and chemical anomalies. Despite the accuracy of seismic information, uncertainties and trade-off still prevent the determination of a detailed lower mantle thermo-chemical structure. For instance, the nature of chemical heterogeneities and the exact role played by the post-perovskite phase transition are still debated. Additional constraints are needed to discriminate between the possible models of structure and <span class="hlt">dynamics</span> of the lower mantle. Here, we consider two potential additional constraints, the electrical conductivity and the <span class="hlt">dynamic</span> <span class="hlt">topography</span> at the core-mantle boundary (CMB). Unlike density and seismic velocities, electrical conductivity increases with temperature. In addition, it strongly varies with the iron and silicate content. Using appropriate mineral physics data, we calculated a 3D distribution of electrical conductivity in lower mantle from the thermo-chemical structure inferred by probabilistic tomography, which maps iron and silicate excess in the LLSVP. In the lowermost mantle, we observe a belt of high conductivity, with maximum values around 20 S/m located in the LLSVP. Such a belt may trigger electric currents in the lowermost mantle and induce magnetic field variations with period of one year or more. It may thus be seen by global models of electrical conductivity. Unfortunately, such models do not sample yet regions deeper than 2000 km. A second, independent constraint we explored is the <span class="hlt">dynamic</span> <span class="hlt">topography</span> at the CMB. We used stagYY to calculate the <span class="hlt">dynamic</span> <span class="hlt">topography</span> associated with several models of thermo-chemical convection, and observe strong differences</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_14 --> <div id="page_15" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="281"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27288809','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27288809"><span id="translatedtitle">Spike voltage <span class="hlt">topography</span> in temporal lobe epilepsy.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Asadi-Pooya, Ali A; Asadollahi, Marjan; Shimamoto, Shoichi; Lorenzo, Matthew; Sperling, Michael R</p> <p>2016-07-15</p> <p>We investigated the voltage <span class="hlt">topography</span> of interictal spikes in patients with temporal lobe epilepsy (TLE) to see whether <span class="hlt">topography</span> was related to etiology for TLE. Adults with TLE, who had epilepsy surgery for drug-resistant seizures from 2011 until 2014 at Jefferson Comprehensive Epilepsy Center were selected. Two groups of patients were studied: patients with mesial temporal sclerosis (MTS) on MRI and those with other MRI findings. The voltage <span class="hlt">topography</span> maps of the interictal spikes at the peak were created using BESA software. We classified the interictal spikes as polar, basal, lateral, or others. Thirty-four patients were studied, from which the characteristics of 340 spikes were investigated. The most common type of spike orientation was others (186 spikes; 54.7%), followed by lateral (146; 42.9%), polar (5; 1.5%), and basal (3; 0.9%). Characteristics of the voltage <span class="hlt">topography</span> maps of the spikes between the two groups of patients were somewhat different. Five spikes in patients with MTS had polar orientation, but none of the spikes in patients with other MRI findings had polar orientation (odds ratio=6.98, 95% confidence interval=0.38 to 127.38; p=0.07). Scalp topographic mapping of interictal spikes has the potential to offer different information than visual inspection alone. The present results do not allow an immediate clinical application of our findings; however, detecting a polar spike in a patient with TLE may increase the possibility of mesial temporal sclerosis as the underlying etiology. PMID:27288809</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3914801','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3914801"><span id="translatedtitle">Detecting and Quantifying <span class="hlt">Topography</span> in Neural Maps</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Yarrow, Stuart; Razak, Khaleel A.; Seitz, Aaron R.; Seriès, Peggy</p> <p>2014-01-01</p> <p>Topographic maps are an often-encountered feature in the brains of many species, yet there are no standard, objective procedures for quantifying <span class="hlt">topography</span>. Topographic maps are typically identified and described subjectively, but in cases where the scale of the map is close to the resolution limit of the measurement technique, identifying the presence of a topographic map can be a challenging subjective task. In such cases, an objective <span class="hlt">topography</span> detection test would be advantageous. To address these issues, we assessed seven measures (Pearson distance correlation, Spearman distance correlation, Zrehen's measure, topographic product, topological correlation, path length and wiring length) by quantifying <span class="hlt">topography</span> in three classes of cortical map model: linear, orientation-like, and clusters. We found that all but one of these measures were effective at detecting statistically significant <span class="hlt">topography</span> even in weakly-ordered maps, based on simulated noisy measurements of neuronal selectivity and sparse sampling of the maps. We demonstrate the practical applicability of these measures by using them to examine the arrangement of spatial cue selectivity in pallid bat A1. This analysis shows that significantly topographic arrangements of interaural intensity difference and azimuth selectivity exist at the scale of individual binaural clusters. PMID:24505279</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005DPS....37.4708G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005DPS....37.4708G"><span id="translatedtitle">The <span class="hlt">topography</span> of Iapetus' leading side</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Giese, B.; Denk, T.; Neukum, G.; Porco, C. C.; Roatsch, T.; Wagner, R.</p> <p>2005-08-01</p> <p>We have used Cassini-stereo images to derive a topographic model of Iapetus' leading side. The model reveals that Iapetus has substantial <span class="hlt">topography</span> with heights (referenced to a 747 x 744 x 713 km ellipsoid (Thomas et al., in preparation)) in the range of -9 km to +15 km, much more than observed on the icy satellites of Jupiter. There is an old 800 km impact basin centered at 270 degrees E, 40 degrees N with rim <span class="hlt">topography</span> of more than 10 km extending over scales of 300-400 km. The fact that this <span class="hlt">topography</span> did not relax over time may suggest that the lithosphere reached depths larger than the excavation depth at the time of formation, or, if the impact has probed the asthenosphere, that rapid cooling and associated thickening of the lithosphere has prevented relaxation of the rim <span class="hlt">topography</span>. However, the basin floor is almost level with the surroundings and may indicate that asthenospheric flow was important. In this case the flow could have uplifted the rim. Moreover, the model reveals four impact basins (diameters > 300 km) showing central peak massifs but no rings (including inner rings) are observed. This is consistent with a lithosphere sufficiently thick to prevent ring formation. One of the basins with a weakly pronounced central peak has a slightly updomed floor suggesting isostatic rebound. There is a prominent equatorial ridge with heights of more than 12 km and widths < 100 km. The morphology of the ridge suggests a tectonic origin involving upwarping of the surface.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003WRR....39.1334M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003WRR....39.1334M"><span id="translatedtitle">Analysis of small-scale gravel bed <span class="hlt">topography</span> during armoring</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Marion, Andrea; Tait, Simon J.; McEwan, Ian K.</p> <p>2003-12-01</p> <p>In evaluating the resistance of sediment particles to entrainment by the action of the flow in a river, the grain geometry is usually characterized using representative sizes. This approach has been dictated, initially by lack of physical insight, but more recently by the lack of analytical tools able to describe the 3-D nature of surface grain organization on water-worked sediment beds. Laboratory experiments are presented where mixed grain size beds were mobilized under a range of hydraulic and sediment input conditions. Detailed bed <span class="hlt">topography</span> was measured at various stages. Statistical tools have been adopted which describe the degree of surface organization on water-worked sediment bed surfaces. The degree of particle organization and the bed stability can be evaluated in relative terms using the properties of the probability density distribution of the bed surface elevations and in <span class="hlt">absolute</span> terms using a properly defined 2-D structure function. The methods described can be applied directly to natural water-worked surfaces given the availability of appropriate bed surface elevation data sets.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhRvA..92e3827T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhRvA..92e3827T"><span id="translatedtitle"><span class="hlt">Absolute</span> optical instruments without spherical symmetry</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tyc, Tomáš; Dao, H. L.; Danner, Aaron J.</p> <p>2015-11-01</p> <p>Until now, the known set of <span class="hlt">absolute</span> optical instruments has been limited to those containing high levels of symmetry. Here, we demonstrate a method of mathematically constructing refractive index profiles that result in asymmetric <span class="hlt">absolute</span> optical instruments. The method is based on the analogy between geometrical optics and classical mechanics and employs Lagrangians that separate in Cartesian coordinates. In addition, our method can be used to construct the index profiles of most previously known <span class="hlt">absolute</span> optical instruments, as well as infinitely many different ones.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4530887','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4530887"><span id="translatedtitle">NMR and MD Studies Reveal That the Isolated Dengue NS3 Protease Is an Intrinsically Disordered Chymotrypsin Fold Which <span class="hlt">Absolutely</span> Requests NS2B for Correct Folding and Functional <span class="hlt">Dynamics</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Gupta, Garvita; Lim, Liangzhong; Song, Jianxing</p> <p>2015-01-01</p> <p>Dengue genome encodes a two component protease complex (NS2B-NS3pro) essential for the viral maturation/infectivity, thus representing a key drug target. Previously, due to its “complete insolubility”, the isolated NS3pro could not be experimentally studied and it remains elusive what structure it adopts without NS2B and why NS2B is indispensable. Here as facilitated by our previous discovery, the isolated NS3pro has been surprisingly deciphered by NMR to be the first intrinsically-disordered chymotrypsin-like fold, which exists in a loosely-packed state with non-native long-range interactions as revealed by paramagnetic relaxation enhancement (PRE). The disordered NS3pro appears to be needed for binding a human host factor to trigger the membrane remodeling. Moreover, we have in vitro refolded the NS3pro in complex with either NS2B (48–100) or the full-length NS2B (1–130) anchored into the LMPC micelle, and the two complexes have similar activities but different <span class="hlt">dynamics</span>. We also performed molecular <span class="hlt">dynamics</span> (MD) simulations and the results revealed that NS2B shows the highest structural fluctuations in the complex, thus providing the <span class="hlt">dynamic</span> basis for the observation on its conformational exchange between open and closed states. Remarkably, the NS2B cofactor plays a central role in maintaining the correlated motion network required for the catalysis as we previously decoded for the SARS 3CL protease. Indeed, a truncated NS2B (48–100;Δ77–84) with the flexible loop deleted is able to trap the NS2B-NS3pro complex in a highly <span class="hlt">dynamic</span> and catalytically-impotent state. Taken together, our study implies potential strategies to perturb the NS2B-NS3pro interface for design of inhibitors for treating dengue infection. PMID:26258523</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22053941','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22053941"><span id="translatedtitle"><span class="hlt">Absolute</span> charge calibration of scintillating screens for relativistic electron detection</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Buck, A.; Popp, A.; Schmid, K.; Karsch, S.; Krausz, F.; Zeil, K.; Jochmann, A.; Kraft, S. D.; Sauerbrey, R.; Cowan, T.; Schramm, U.; Hidding, B.; Kudyakov, T.; Sears, C. M. S.; Veisz, L.; Pawelke, J.</p> <p>2010-03-15</p> <p>We report on new charge calibrations and linearity tests with high-<span class="hlt">dynamic</span> range for eight different scintillating screens typically used for the detection of relativistic electrons from laser-plasma based acceleration schemes. The <span class="hlt">absolute</span> charge calibration was done with picosecond electron bunches at the ELBE linear accelerator in Dresden. The lower detection limit in our setup for the most sensitive scintillating screen (KODAK Biomax MS) was 10 fC/mm{sup 2}. The screens showed a linear photon-to-charge dependency over several orders of magnitude. An onset of saturation effects starting around 10-100 pC/mm{sup 2} was found for some of the screens. Additionally, a constant light source was employed as a luminosity reference to simplify the transfer of a one-time <span class="hlt">absolute</span> calibration to different experimental setups.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010RScI...81c3301B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010RScI...81c3301B"><span id="translatedtitle"><span class="hlt">Absolute</span> charge calibration of scintillating screens for relativistic electron detection</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Buck, A.; Zeil, K.; Popp, A.; Schmid, K.; Jochmann, A.; Kraft, S. D.; Hidding, B.; Kudyakov, T.; Sears, C. M. S.; Veisz, L.; Karsch, S.; Pawelke, J.; Sauerbrey, R.; Cowan, T.; Krausz, F.; Schramm, U.</p> <p>2010-03-01</p> <p>We report on new charge calibrations and linearity tests with high-<span class="hlt">dynamic</span> range for eight different scintillating screens typically used for the detection of relativistic electrons from laser-plasma based acceleration schemes. The <span class="hlt">absolute</span> charge calibration was done with picosecond electron bunches at the ELBE linear accelerator in Dresden. The lower detection limit in our setup for the most sensitive scintillating screen (KODAK Biomax MS) was 10 fC/mm2. The screens showed a linear photon-to-charge dependency over several orders of magnitude. An onset of saturation effects starting around 10-100 pC/mm2 was found for some of the screens. Additionally, a constant light source was employed as a luminosity reference to simplify the transfer of a one-time <span class="hlt">absolute</span> calibration to different experimental setups.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/978296','SCIGOV-STC'); return false;" href="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> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Honnicke, M.G.; Mazzaro, I.; Manica, J.; Benine, E.; M da Costa, E.; Dedavid, B. A.; Cusatis, C.; Huang, X. R.</p> <p>2009-09-13</p> <p>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 <span class="hlt">dynamical</span> 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> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27354728','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27354728"><span id="translatedtitle">Why re-entrant surface <span class="hlt">topography</span> is needed for robust oleophobicity.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Nosonovsky, Michael; Bhushan, Bharat</p> <p>2016-08-01</p> <p>Surface patterns affect wetting properties of solid materials allowing manipulation of the phase state of an adjacent fluid. The best known example of this effect is the superhydrophobic composite (Cassie-Baxter) interface with vapour/air pockets between the solid and liquid. Mathematically, the effect of surface micropatterns can be studied by an averaging technique similarly to the method of separation of motions in <span class="hlt">dynamics</span>. However, averaged parameters are insufficient for robust superhydrophobic and superoleophobic surfaces because additional <span class="hlt">topography</span> features are important: hierarchical organization and re-entrant roughness. The latter is crucial for the oleophobicity because it enhances the stability of a composite interface. The re-entrant <span class="hlt">topography</span> can be achieved by various methods. Understanding the role of re-entrant surface <span class="hlt">topography</span> gives us new insights on the multitude of wetting scenarios beyond the standard Wenzel and Cassie-Baxter models.This article is part of the themed issue 'Bioinspired hierarchically structured surfaces for green science'. PMID:27354728</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AGUFM.H52A..05M','NASAADS'); return false;" href="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> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>McElroy, B.; Jerolmack, D.; Mohrig, D.</p> <p>2005-12-01</p> <p>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 <span class="hlt">dynamic</span> 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 <span class="hlt">dynamic</span> 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 <span class="hlt">dynamic</span> 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</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.5966S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.5966S"><span id="translatedtitle">The influence of <span class="hlt">topography</span> and vegetation self-organization over resource fluxes in wetland ecosystems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stieglitz, Marc; Cheng, Yiwei; Truk, Greg; Engel, Victor; Ross, Joshua</p> <p>2014-05-01</p> <p>While it is recognized that <span class="hlt">topography</span> and vegetation self-organization (SO) are both first order controls over ecosystem <span class="hlt">dynamics</span>, the discrete contributions that these two controls have over ecosystem functioning have not been studied in any rigorous way. This work is focused on systematically isolating the separate and combined impacts of <span class="hlt">topography</span> and SO over vegetation <span class="hlt">dynamics</span>. We simulate the steady state and transient <span class="hlt">dynamics</span> of nitrogen-limited patterned peat vegetation observed in the bogs of northern Siberia. We do so across a realistic range of land slopes, nutrient limitation values, and rainfall amounts. Simulation results show that on relatively shallow slopes, vegetation SO is a primary control over the spatial arrangement of vegetation, and that such self-organized arrangements yield the most efficient capture of ecosystem resources. However, as slope increases, and or resource limitation is low, <span class="hlt">topography</span> begins to exert its control over the temporal and spatial <span class="hlt">dynamics</span>. As will be discussed, these results suggest a simple continuum framework, valid across biomes, for understanding the interplay between these two first order controls. Specifically, as resources (e.g., water, nutrients) increase, ecosystem <span class="hlt">dynamics</span> shift towards topographic control, while when resources are reduced, ecosystem <span class="hlt">dynamics</span> shift towards vegetation SO control.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EPSC...10..717D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EPSC...10..717D"><span id="translatedtitle"><span class="hlt">Absolute</span> magnitudes of trans-neptunian objects</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Duffard, R.; Alvarez-candal, A.; Pinilla-Alonso, N.; Ortiz, J. L.; Morales, N.; Santos-Sanz, P.; Thirouin, A.</p> <p>2015-10-01</p> <p>Accurate measurements of diameters of trans- Neptunian objects are extremely complicated to obtain. Radiomatric techniques applied to thermal measurements can provide good results, but precise <span class="hlt">absolute</span> magnitudes are needed to constrain diameters and albedos. Our objective is to measure accurate <span class="hlt">absolute</span> magnitudes for a sample of trans- Neptunian objects, many of which have been observed, and modelled, by the "TNOs are cool" team, one of Herschel Space Observatory key projects grantes with ~ 400 hours of observing time. We observed 56 objects in filters V and R, if possible. These data, along with data available in the literature, was used to obtain phase curves and to measure <span class="hlt">absolute</span> magnitudes by assuming a linear trend of the phase curves and considering magnitude variability due to rotational light-curve. In total we obtained 234 new magnitudes for the 56 objects, 6 of them with no reported previous measurements. Including the data from the literature we report a total of 109 <span class="hlt">absolute</span> magnitudes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=organic+AND+carbon&pg=5&id=EJ288694','ERIC'); return false;" href="http://eric.ed.gov/?q=organic+AND+carbon&pg=5&id=EJ288694"><span id="translatedtitle">A New Gimmick for Assigning <span class="hlt">Absolute</span> Configuration.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Ayorinde, F. O.</p> <p>1983-01-01</p> <p>A five-step procedure is provided to help students in making the assignment <span class="hlt">absolute</span> configuration less bothersome. Examples for both single (2-butanol) and multi-chiral carbon (3-chloro-2-butanol) molecules are included. (JN)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AdWR...94..400C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AdWR...94..400C"><span id="translatedtitle">Impact of watershed <span class="hlt">topography</span> on hyporheic exchange</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Caruso, Alice; Ridolfi, Luca; Boano, Fulvio</p> <p>2016-08-01</p> <p>Among the interactions between surface water bodies and aquifers, hyporheic exchange has been recognized as a key process for nutrient cycling and contaminant transport. Even though hyporheic exchange is strongly controlled by groundwater discharge, our understanding of the impact of the regional groundwater flow on hyporheic fluxes is still limited because of the complexity arising from the multi-scale nature of these interactions. In this work, we investigate the role of watershed <span class="hlt">topography</span> on river-aquifer interactions by way of a semi-analytical model, in which the landscape <span class="hlt">topography</span> is used to approximate the groundwater head distribution. The analysis of a case study shows how the complex topographic structure is the direct cause of a substantial spatial variability of the aquifer-river exchange. Groundwater upwelling along the river corridor is estimated and its influence on the hyporheic zone is discussed. In particular, the fragmentation of the hyporeic corridor induced by groundwater discharge at the basin scale is highlighted.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/22905865','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22905865"><span id="translatedtitle">Determination of ¹⁵N-incorporation into plant proteins and their <span class="hlt">absolute</span> quantitation: a new tool to study nitrogen flux <span class="hlt">dynamics</span> and protein pool sizes elicited by plant-herbivore interactions.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ullmann-Zeunert, Lynn; Muck, Alexander; Wielsch, Natalie; Hufsky, Franziska; Stanton, Mariana A; Bartram, Stefan; Böcker, Sebastian; Baldwin, Ian T; Groten, Karin; Svatoš, Aleš</p> <p>2012-10-01</p> <p>Herbivory leads to changes in the allocation of nitrogen among different pools and tissues; however, a detailed quantitative analysis of these changes has been lacking. Here, we demonstrate that a mass spectrometric data-independent acquisition approach known as LC-MS(E), combined with a novel algorithm to quantify heavy atom enrichment in peptides, is able to quantify elicited changes in protein amounts and (15)N flux in a high throughput manner. The reliable identification/quantitation of rabbit phosphorylase b protein spiked into leaf protein extract was achieved. The linear <span class="hlt">dynamic</span> range, reproducibility of technical and biological replicates, and differences between measured and expected (15)N-incorporation into the small (SSU) and large (LSU) subunits of ribulose-1,5-bisphosphate-carboxylase/oxygenase (RuBisCO) and RuBisCO activase 2 (RCA2) of Nicotiana attenuata plants grown in hydroponic culture at different known concentrations of (15)N-labeled nitrate were used to further evaluate the procedure. The utility of the method for whole-plant studies in ecologically realistic contexts was demonstrated by using (15)N-pulse protocols on plants growing in soil under unknown (15)N-incorporation levels. Additionally, we quantified the amounts of lipoxygenase 2 (LOX2) protein, an enzyme important in antiherbivore defense responses, demonstrating that the approach allows for in-depth quantitative proteomics and (15)N flux analyses of the metabolic <span class="hlt">dynamics</span> elicited during plant-herbivore interactions. PMID:22905865</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19980216243&hterms=Herbs&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DHerbs','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19980216243&hterms=Herbs&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DHerbs"><span id="translatedtitle"><span class="hlt">Topography</span> over South America from ERS altimetry</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Brenner, Anita; Frey, Herb; DiMarzio, John; Tsaoussi, Lucia</p> <p>1997-01-01</p> <p>The results of the surface <span class="hlt">topography</span> mapping of South America during the ERS-1 geodetic mission are presented. The altimeter waveforms, the range measurement, and the internal and Doppler range corrections were obtained. The atmospheric corrections and solid tides were calculated. Comparisons between Shuttle laser altimetry and ERS-1 altimetry grid showed good agreement. Satellite radar altimetry data can be used to improve the topographic knowledge of regions for which only poor elevation data currently exist.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.usgs.gov/ds/418/','USGSPUBS'); return false;" href="http://pubs.usgs.gov/ds/418/"><span id="translatedtitle">ATM Coastal <span class="hlt">Topography</span>-Alabama 2001</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Nayegandhi, Amar; Yates, Xan; Brock, John C.; Sallenger, A.H.; Bonisteel, Jamie M.; Klipp, Emily S.; Wright, C. Wayne</p> <p>2009-01-01</p> <p>These remotely sensed, geographically referenced elevation measurements of Lidar-derived first surface (FS) <span class="hlt">topography</span> were produced collaboratively by the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL, and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of the Alabama coastline, acquired October 3-4, 2001. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative scanning Lidar instrument originally developed by NASA, and known as the Airborne Topographic Mapper (ATM), was used during data acquisition. The ATM system is a scanning Lidar system that measures high-resolution <span class="hlt">topography</span> of the land surface, and incorporates a green-wavelength laser operating at pulse rates of 2 to 10 kilohertz. Measurements from the laser ranging device are coupled with data acquired from inertial navigation system (INS) attitude sensors and differentially corrected global positioning system (GPS) receivers to measure <span class="hlt">topography</span> of the surface at accuracies of +/-15 centimeters. The nominal ATM platform is a Twin Otter or P-3 Orion aircraft, but the instrument may be deployed on a range of light aircraft. Elevation measurements were collected over the survey area using the ATM system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of Lidar data in an interactive or batch mode. Modules for pre-survey flight line definition, flight path plotting, Lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is routinely used to create maps that</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.usgs.gov/ds/450/','USGSPUBS'); return false;" href="http://pubs.usgs.gov/ds/450/"><span id="translatedtitle">ATM Coastal <span class="hlt">Topography</span>-Mississippi, 2001</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Nayegandhi, Amar; Yates, Xan; Brock, John C.; Sallenger, A.H.; Klipp, Emily S.; Wright, C. Wayne</p> <p>2009-01-01</p> <p>These remotely sensed, geographically referenced elevation measurements of lidar-derived first-surface (FS) <span class="hlt">topography</span> were produced collaboratively by the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL, and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of the Mississippi coastline, from Lakeshore to Petit Bois Island, acquired September 9-10, 2001. The datasets are made available for use as a management tool to research scientists and natural-resource managers. An innovative scanning lidar instrument originally developed by NASA, and known as the Airborne Topographic Mapper (ATM), was used during data acquisition. The ATM system is a scanning lidar system that measures high-resolution <span class="hlt">topography</span> of the land surface and incorporates a green-wavelength laser operating at pulse rates of 2 to 10 kilohertz. Measurements from the laser-ranging device are coupled with data acquired from inertial navigation system (INS) attitude sensors and differentially corrected global positioning system (GPS) receivers to measure <span class="hlt">topography</span> of the surface at accuracies of +/-15 centimeters. The nominal ATM platform is a Twin Otter or P-3 Orion aircraft, but the instrument may be deployed on a range of light aircraft. Elevation measurements were collected over the survey area using the ATM system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of lidar data in an interactive or batch mode. Modules for presurvey flight-line definition, flight-path plotting, lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19880021047','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19880021047"><span id="translatedtitle">Diffraction imaging (<span class="hlt">topography</span>) with monochromatic synchrotron radiation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Steiner, Bruce; Kuriyama, Masao; Dobbyn, Ronald C.; Laor, Uri</p> <p>1988-01-01</p> <p>Structural information of special interest to crystal growers and device physicists is now available from high resolution monochromatic synchrotron diffraction imaging (<span class="hlt">topography</span>). 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.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_15 --> <div id="page_16" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="301"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EGUGA..1211784Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EGUGA..1211784Z"><span id="translatedtitle">Solutions of barotropic trapped waves over <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zavala Sanson, Luis</p> <p>2010-05-01</p> <p>Solutions of free, barotropic waves over variable <span class="hlt">topography</span> are derived. In particular, we examine two cases: waves around axisymmetric seamounts and waves along a sloping bottom. Even though these types of oscillations have been studied before, we revisit the problem because of two main reasons: (i) The linear, barotropic, shallow-water equations with a rigid lid are now solved with no further approximations, in contrast with previous studies. (ii) The solutions are applied to a wide family of seamounts and bottom slopes with profiles proportional to exp(rs) and ys, respectively, where r is the radial distance from the centre of the mountain, y is the direction perpendicular to the slope, and s is an arbitrary positive real number. Most of previous works on seamounts are restricted to the special case s = 2. By varying the shape parameter one can study trapped waves around flat-topped seamounts or guyots (s > 2) or sharp, cone-shaped <span class="hlt">topographies</span> (s < 2). Similarly, most of previous studies on sloping bottoms report cases with s = 1 (linear slopes), whilst the present results are applied to more general bottom profiles. The resulting dispersion relation in both cases possess a remarkable simplicity that reveals a number of wave characteristics as a function of the <span class="hlt">topography</span> shape.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/ofr20071431','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/ofr20071431"><span id="translatedtitle">EAARL <span class="hlt">Topography</span>-Padre Island National Seashore</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Brock, John C.; Wright, C. Wayne; Nayegandhi, Amar; Patterson, Matt; Wilson, Iris; Travers, Laurinda J.</p> <p>2007-01-01</p> <p>This Web site contains 116 Lidar-derived bare earth <span class="hlt">topography</span> maps and GIS files for Padre Island National Seashore-Texas. These Lidar-derived <span class="hlt">topography</span> 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 <span class="hlt">topography</span> 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/8450433','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/8450433"><span id="translatedtitle">Corneal <span class="hlt">topography</span> of excimer laser photorefractive keratectomy.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Klyce, S D; Smolek, M K</p> <p>1993-01-01</p> <p>The application of the 193 nm excimer laser for keratorefractive surgery promises to deliver a higher degree of precision and predictability than traditional procedures such as radial keratotomy. The development and evaluation of keratorefractive surgery have benefited from the parallel advances made in the field of corneal <span class="hlt">topography</span> analysis. We used the Computed Anatomy <span class="hlt">Topography</span> Modeling System (TMS-1) to analyze a Louisiana State University (LSU) Eye Center series of patients who had photorefractive keratectomy for the treatment of myopia with the VISX Twenty/Twenty excimer laser system. The excimer ablations were characterized by a relatively uniform distribution of surface powers within the treated zone. In the few cases that exhibited marked refractive regression, corneal <span class="hlt">topography</span> analysis showed correlative changes. With topographical analysis, centration of the ablations relative to the center of the pupil could be evaluated. Marked improvement in centration occurred in the patients of LSU Series IIB in which the procedure to locate the point on the cornea directly over the pupil's center during surgery was refined. Corneal topographical analysis provides objective measures of keratorefractive surgical results and is able to measure the precise tissue removal effect of excimer laser ablation without the uncertainties caused by measuring visual acuity alone. Our observations forecast the need for improved aids to center the laser ablations and for the development of a course of treatment to prevent post-ablation stromal remodeling. PMID:8450433</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.usgs.gov/of/2007/1179/','USGSPUBS'); return false;" href="http://pubs.usgs.gov/of/2007/1179/"><span id="translatedtitle">EAARL <span class="hlt">topography</span>: George Washington Birthplace National Monument</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Brock, John C.; Wright, C. Wayne; Patterson, Matt; Nayegandhi, Amar; Patterson, Judd</p> <p>2007-01-01</p> <p>This Web site contains Lidar-derived <span class="hlt">topography</span> (first return and bare earth) maps and GIS files for George Washington Birthplace National Monument in Virginia. These lidar-derived <span class="hlt">topography</span> maps were produced as a collaborative effort between the U.S. Geological Survey (USGS) Coastal and Marine Geology Program, FISC St. Petersburg, the National Park Service (NPS), Northeast Coastal and Barrier 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 <span class="hlt">topography</span> 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 coastal resource managers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011SPIE.8011E..7TA','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011SPIE.8011E..7TA"><span id="translatedtitle">Digital holography system for <span class="hlt">topography</span> measurement</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Amezquita, R.; Rincon, O. J.; Torres, Y. M.; Amezquita, S.</p> <p>2011-08-01</p> <p>The optical characteristics of Diffractive Optical Elements are determined by the properties of the photosensitive film on which they are produced. When working with photoresist plates, the most important property is the change in the plate's <span class="hlt">topography</span> for different exposures. In this case, the required characterization involves a topographic measurement that can be made using digital holography. This work presents a digital holography system in which a hologram's phase map is obtained from a single recorded image. The phase map is calculated by applying a phase-shifting algorithm to a set of images that are created using a digital phase-shifting/tilteliminating procedure. Also, the curvatures, introduced by the imaging elements used in the experimental setup, are digitally compensated for using a polynomial fitting-method. The object's <span class="hlt">topography</span> is then obtained from this modified phase map. To demonstrate the proposed procedure, the <span class="hlt">topography</span> of patches exposed on a Shipley 1818 photoresist plate by microlithography equipment-which is currently under construction-is shown.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.usgs.gov/of/2007/1178/','USGSPUBS'); return false;" href="http://pubs.usgs.gov/of/2007/1178/"><span id="translatedtitle">EAARL <span class="hlt">topography</span>: Gateway National Recreation Area</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Brock, John C.; Wright, C. Wayne; Patterson, Matt; Nayegandhi, Amar; Patterson, Judd</p> <p>2007-01-01</p> <p>This Web site contains Lidar-derived <span class="hlt">topography</span> (bare earth) maps and GIS files for the Sandy Hook Unit within Gateway National Recreation Area in New Jersey. These Lidar-derived <span class="hlt">topography</span> maps were produced as a collaborative effort between the U.S. Geological Survey (USGS) Coastal and Marine Geology Program, FISC St. Petersburg, the National Park Service (NPS) South Florida/Caribbean 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 <span class="hlt">topography</span> 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.usgs.gov/of/2007/1177/','USGSPUBS'); return false;" href="http://pubs.usgs.gov/of/2007/1177/"><span id="translatedtitle">EAARL <span class="hlt">topography</span>: Thomas Stone National Historic Site</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Brock, John C.; Wright, C. Wayne; Patterson, Matt; Nayegandhi, Amar; Patterson, Judd</p> <p>2007-01-01</p> <p>This Web site contains Lidar-derived <span class="hlt">topography</span> (first return and bare earth) maps and GIS files for Thomas Stone National Historic Site in Maryland. These Lidar-derived <span class="hlt">topography</span> maps were produced as a collaborative effort between the U.S. Geological Survey (USGS) Coastal and Marine Geology Program, FISC St. Petersburg, the National Park Service (NPS) South Florida/Caribbean 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 <span class="hlt">topography</span> 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1993QuEle..23..535V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1993QuEle..23..535V"><span id="translatedtitle">EFFECT OF LASER LIGHT ON MATTER. LASER PLASMAS: Optical visualization of the <span class="hlt">topography</span> of a crater formed on a solid sample by a laser pulse</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vasil'ev, Sergei V.; Ivanov, A. Yu; Lyalikov, A. M.</p> <p>1993-06-01</p> <p>A fringe projection method has been used to determine the shape of a crater formed by applying laser light to a metal plate. The crater <span class="hlt">topography</span> should be taken into account in thermal, acoustic, and plasma-<span class="hlt">dynamics</span> calculations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014IJMES..45..923S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014IJMES..45..923S"><span id="translatedtitle"><span class="hlt">Absolute</span> value equations - what can we learn from their graphical representation?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stupel, Moshe; Ben-Chaim, David</p> <p>2014-08-01</p> <p>Understanding graphical representations of algebraic equations, particularly graphical representations of <span class="hlt">absolute</span> value equations, significantly improves students' mathematical comprehension and ignites within them an appreciation of the beauty and aesthetics of mathematics. In this paper, we focus on <span class="hlt">absolute</span> value equations of linear and quadratic expressions, by examining various cases, presenting different methods of solving them by graphical representation, exhibiting the advantage of using <span class="hlt">dynamic</span> software such as GeoGebra in solving them, and illustrating some examples of interesting graphical solutions. We recommend that teachers take advantage of the rapid development in technology to help learners tangibly visualize the solutions of <span class="hlt">absolute</span> value equations before proceeding to the analytical solutions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015Geomo.246..394G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015Geomo.246..394G"><span id="translatedtitle">Reenvisioning cross-sectional at-a-station hydraulic geometry as spatially explicit hydraulic <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gonzalez, R. L.; Pasternack, G. B.</p> <p>2015-10-01</p> <p>Transect-based hydraulic geometry is well established but depends on a complex set of subjective fieldwork and computational decisions that sometimes go unexplained. As a result, it is ripe for reenvisioning in the light of the emergence of meter-scale, spatially explicit data and algorithmic geospatial analysis. This study developed and evaluated a new spatially explicit method for analyzing discharge-dependent hydraulics coined 'hydraulic <span class="hlt">topography</span>' that not only increases accuracy but also eliminates several sample- and assumption-based inconsistencies. Using data and hydrodynamic simulations from the regulated, gravel-cobble-bed lower Yuba River in California, power functions were fitted to discharge-dependent average width, depth, and depth-weighted velocity for three spatial scales and then their corresponding exponents and coefficients were compared across scales and against ones computed using traditional approaches. Average hydraulic values from cross sections at the segment scale spanned up to 1.5 orders of magnitude for a given discharge. Transect-determined exponents for reach-scale depth and velocity relations were consistently over- and underestimated, respectively, relative to the hydraulic <span class="hlt">topography</span> benchmark. Overall, 73% of cross-sectional power regression parameters assessed fell between 10 and 50 <span class="hlt">absolute</span> percent error with respect to the spatially explicit hydraulic <span class="hlt">topography</span> baseline. Although traditional transect-based sampling may be viable for certain uses, percent errors of this magnitude could compromise engineering applications in river management and training works.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19800023351','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19800023351"><span id="translatedtitle">State estimation and <span class="hlt">absolute</span> image registration for geosynchronous satellites</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Nankervis, R.; Koch, D. W.; Sielski, H.</p> <p>1980-01-01</p> <p>Spacecraft state estimation and the <span class="hlt">absolute</span> registration of Earth images acquired by cameras onboard geosynchronous satellites are described. The basic data type of the procedure consists of line and element numbers of image points called landmarks whose geodetic coordinates, relative to United States Geodetic Survey topographic maps, are known. A conventional least squares process is used to estimate navigational parameters and camera pointing biases from observed minus computed landmark line and element numbers. These estimated parameters along with orbit and attitude <span class="hlt">dynamic</span> models are used to register images, using an automated grey level correlation technique, inside the span represented by the landmark data. In addition, the <span class="hlt">dynamic</span> models can be employed to register images outside of the data span in a near real time mode. An important application of this mode is in support of meteorological studies where rapid data reduction is required for the rapid tracking and predicting of <span class="hlt">dynamic</span> phenomena.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011CG.....37.1793H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011CG.....37.1793H"><span id="translatedtitle">An algorithm for generalizing <span class="hlt">topography</span> to grids while preserving subscale morphologic characteristics—creating a glacier bed DEM for Jakobshavn trough as low-resolution input for <span class="hlt">dynamic</span> ice-sheet models</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Herzfeld, Ute C.; Wallin, Bruce F.; Leuschen, Carlton J.; Plummer, Joel</p> <p>2011-11-01</p> <p>The objective of this paper is to derive an algorithm for preserving important subscale morphologic characteristics at grids of lower-resolution, in particular for linear features such as canyons and ridge lines. The development of such an algorithm is necessitated by applications that require reduced spatial resolution, as is common in cartographic generalization, GIS applications, and geophysical modeling. Since any algorithm that results in weighted averages, including optimum interpolation and ordinary kriging, cannot reproduce correct depths, a new algorithm is designed based on principles of mathematical morphology. The algorithm described here is applied to derive a subglacial bed of the Greenland Ice Sheet that includes the trough of Jakobshavn Isbræ as a continuous canyon at correct depth in a low-resolution (5-km) digital elevation model (DEM). Data from recent airborne radar measurements of the elevation of the subglacial bed as part of the CReSIS project are utilized. The morphologic algorithm is designed with geophysical ice-sheet modeling in mind, in the following context. Currently occurring changes in the Earth's climate and the cryosphere cause changes in sea level, and the societal relevance of these natural processes motivates estimation of maximal sea-level rise in the medium-term future. The fast-moving outlet glaciers are more sensitive to climatic change than other parts of the Greenland ice sheet. Jakobshavn Isbrae, the fastest-moving ice stream in Greenland, follows a subglacial geologic trough. Since the existence of the trough causes the acceleration of the slow-moving inland ice in the Jakobshavn region and the formation of the ice stream, correct representation of the trough in a DEM is essential to model changes in the <span class="hlt">dynamics</span> of the ice sheet and resultant sea-level predictions, even if current ice-sheet models can typically be run only at 5-km resolution. The DEM resultant from this study helps to bridge the conceptual gap between</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013EGUGA..1513326C&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013EGUGA..1513326C&link_type=ABSTRACT"><span id="translatedtitle">Open<span class="hlt">Topography</span>: Enabling Online Access to High-Resolution Lidar <span class="hlt">Topography</span> Data and Processing Tools</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Crosby, Christopher; Nandigam, Viswanath; Baru, Chaitan; Arrowsmith, J. Ramon</p> <p>2013-04-01</p> <p>High-resolution <span class="hlt">topography</span> data acquired with lidar (light detection and ranging) technology are revolutionizing the way we study the Earth's surface and overlying vegetation. These data, collected from airborne, tripod, or mobile-mounted scanners have emerged as a fundamental tool for research on topics ranging from earthquake hazards to hillslope processes. Lidar data provide a digital representation of the earth's surface at a resolution sufficient to appropriately capture the processes that contribute to landscape evolution. The U.S. National Science Foundation-funded Open<span class="hlt">Topography</span> Facility (http://www.opentopography.org) is a web-based system designed to democratize access to earth science-oriented lidar <span class="hlt">topography</span> data. Open<span class="hlt">Topography</span> provides free, online access to lidar data in a number of forms, including the raw point cloud and associated geospatial-processing tools for customized analysis. The point cloud data are co-located with on-demand processing tools to generate digital elevation models, and derived products and visualizations which allow users to quickly access data in a format appropriate for their scientific application. The Open<span class="hlt">Topography</span> system is built using a service-oriented architecture (SOA) that leverages cyberinfrastructure resources at the San Diego Supercomputer Center at the University of California San Diego to allow users, regardless of expertise level, to access these massive lidar datasets and derived products for use in research and teaching. Open<span class="hlt">Topography</span> hosts over 500 billion lidar returns covering 85,000 km2. These data are all in the public domain and are provided by a variety of partners under joint agreements and memoranda of understanding with Open<span class="hlt">Topography</span>. Partners include national facilities such as the NSF-funded National Center for Airborne Lidar Mapping (NCALM), as well as non-governmental organizations and local, state, and federal agencies. Open<span class="hlt">Topography</span> has become a hub for high-resolution <span class="hlt">topography</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016E%26PSL.449..282F&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016E%26PSL.449..282F&link_type=ABSTRACT"><span id="translatedtitle">Decoupling of modern shortening rates, climate, and <span class="hlt">topography</span> in the Caucasus</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Forte, Adam M.; Whipple, Kelin X.; Bookhagen, Bodo; Rossi, Matthew W.</p> <p>2016-09-01</p> <p> to <span class="hlt">dynamic</span> <span class="hlt">topography</span> from detachment of the north-directed Greater Caucasus slab or to a recent slowing of convergence rates. Large-scale spatial gradients in climate are not reflected in the <span class="hlt">topography</span> of the Caucasus and do not seem to exert any significant control on the tectonics or structure of either range.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFMDI32A..02M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFMDI32A..02M"><span id="translatedtitle">Reconstructing African <span class="hlt">topography</span> over the past 30 Myrs with high-resolution tomography-based convection modelling</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Moucha, R.; Forte, A. M.; Rowley, D. B.; Braun, J.; Mitrovica, J. X.; Simmons, N. A.; Grand, S. P.</p> <p>2009-12-01</p> <p>Geologists (e.g. Krenkel 1922; Holmes 1944; Burke 1996) have long recognized the unique 'basin and swell' structure of the African continent and adjoining ocean basins. This <span class="hlt">topography</span> is unique on our planet and is characterized by large-scale extensional features such as the East African Rift, recent widespread magmatic activity, and epeirogeny. These enigmatic surface features have long suggested that the African continent is shaped by significant <span class="hlt">dynamic</span> forcing originating in the underlying mantle. Utilizing present-day heterogeneity derived from a high-resolution joint seismic-geodynamic tomography model (Simmons et al., 2009), we reconstruct the late Cenozoic <span class="hlt">dynamic</span> <span class="hlt">topography</span> of Africa by carrying out backward-in-time mantle flow simulations. In this presentation we will explore the geological implications, and associated uncertainties, of our predictions of the temporal evolution of African <span class="hlt">topography</span>, with a particular focus on the most <span class="hlt">dynamic</span> surface features such as the East African Rift system and adjacent basins.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.6526G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.6526G"><span id="translatedtitle">Geophysical, petrological and mineral physics constraints on Earth's surface <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Guerri, Mattia; Cammarano, Fabio; Tackley, Paul J.</p> <p>2015-04-01</p> <p>Earth's surface <span class="hlt">topography</span> is controlled by isostatically compensated density variations within the lithosphere, but <span class="hlt">dynamic</span> <span class="hlt">topography</span> - i.e. the <span class="hlt">topography</span> due to adjustment of surface to mantle convection - is an important component, specially at a global scale. In order to separate these two components it is fundamental to estimate crustal and mantle density structure and rheological properties. Usually, crustal density is constrained from interpretation of available seismic data (mostly VP profiles) based on empirical relationships such those in Brocher [2005]. Mantle density structure is inferred from seismic tomography models. Constant coefficients are used to interpret seismic velocity anomalies in density anomalies. These simplified methods are unable to model the effects that pressure and temperature variations have on mineralogical assemblage and physical properties. Our approach is based on a multidisciplinary method that involves geophysical observables, mineral physics constraints, and petrological data. Mantle density is based on the thermal interpretation of global seismic tomography models assuming various compositional structures, as in Cammarano et al. [2011]. We further constrain the top 150 km by including heat-flow data and considering the thermal evolution of the oceanic lithosphere. Crustal density is calculated as in Guerri and Cammarano [2015] performing thermodynamic modeling of various average chemical compositions proposed for the crust. The modeling, performed with the code PerpleX [Connolly, 2005], relies on the thermodynamic dataset from Holland and Powell [1998]. Compressional waves velocity and crustal layers thickness from the model CRUST 1.0 [Laske et al., 2013] offer additional constrains. The resulting lithospheric density models are tested against gravity (GOCE) data. Various crustal and mantle density models have been tested in order to ascertain the effects that uncertainties in the estimate of those features have on the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/19831037','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/19831037"><span id="translatedtitle">Jasminum flexile flower <span class="hlt">absolute</span> from India--a detailed comparison with three other jasmine <span class="hlt">absolutes</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Braun, Norbert A; Kohlenberg, Birgit; Sim, Sherina; Meier, Manfred; Hammerschmidt, Franz-Josef</p> <p>2009-09-01</p> <p>Jasminum flexile flower <span class="hlt">absolute</span> from the south of India and the corresponding vacuum headspace (VHS) sample of the <span class="hlt">absolute</span> were analyzed using GC and GC-MS. Three other commercially available Indian jasmine <span class="hlt">absolutes</span> from the species: J. sambac, J. officinale subsp. grandiflorum, and J. auriculatum and the respective VHS samples were used for comparison purposes. One hundred and twenty-one compounds were characterized in J. flexile flower <span class="hlt">absolute</span>, with methyl linolate, benzyl salicylate, benzyl benzoate, (2E,6E)-farnesol, and benzyl acetate as the main constituents. A detailed olfactory evaluation was also performed. PMID:19831037</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016ufm..conf..509K&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016ufm..conf..509K&link_type=ABSTRACT"><span id="translatedtitle">Universal Cosmic <span class="hlt">Absolute</span> and Modern Science</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kostro, Ludwik</p> <p></p> <p>The official Sciences, especially all natural sciences, respect in their researches the principle of methodic naturalism i.e. they consider all phenomena as entirely natural and therefore in their scientific explanations they do never adduce or cite supernatural entities and forces. The purpose of this paper is to show that Modern Science has its own self-existent, self-acting, and self-sufficient Natural All-in Being or Omni-Being i.e. the entire Nature as a Whole that justifies the scientific methodic naturalism. Since this Natural All-in Being is one and only It should be considered as the own scientifically justified Natural <span class="hlt">Absolute</span> of Science and should be called, in my opinion, the Universal Cosmic <span class="hlt">Absolute</span> of Modern Science. It will be also shown that the Universal Cosmic <span class="hlt">Absolute</span> is ontologically enormously stratified and is in its ultimate i.e. in its most fundamental stratum trans-reistic and trans-personal. It means that in its basic stratum. It is neither a Thing or a Person although It contains in Itself all things and persons with all other sentient and conscious individuals as well, On the turn of the 20th century the Science has begun to look for a theory of everything, for a final theory, for a master theory. In my opinion the natural Universal Cosmic <span class="hlt">Absolute</span> will constitute in such a theory the radical all penetrating Ultimate Basic Reality and will substitute step by step the traditional supernatural personal <span class="hlt">Absolute</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUFM.H42C..04Q','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUFM.H42C..04Q"><span id="translatedtitle">Karst Water System Investigated by <span class="hlt">Absolute</span> Gravimetry</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Quinif, Y.; Meus, P.; van Camp, M.; Kaufmann, O.; van Ruymbeke, M.; Vandiepenbeeck, M.; Camelbeeck, T.</p> <p>2006-12-01</p> <p>The highly anisotropic and heterogeneous hydrogeological characteristics of karst aquifers are difficult to characterize and present challenges for modeling of storage capacities. Little is known about the surface and groundwater interconnection, about the connection between the porous formations and the draining cave and conduits, and about the variability of groundwater volume within the system. Usually, an aquifer is considered as a black box, where water fluxes are monitored as input and output. However, water inflow and outflow are highly variable and cannot be measured directly. A recent project, begun in 2006 sought to constrain the water budget in a Belgian karst aquifer and to assess the porosity and water <span class="hlt">dynamics</span>, combining <span class="hlt">absolute</span> gravity (AG) measurements and piezometric levels around the Rochefort cave. The advantage of gravity measurements is that they integrate all the subsystems in the karst system. This is not the case with traditional geophysical tools like boring or monitoring wells, which are soundings affected by their near environment and its heterogeneity. The investigated cave results from the meander cutoff system of the Lomme River. The main inputs are swallow holes of the river crossing the limestone massif. The river is canalized and the karst system is partly disconnected from the hydraulic system. In February and March 2006, when the river spilled over its dyke and sank into the most important swallow hole, this resulted in dramatic and nearly instantaneous increases in the piezometric levels in the cave, reaching up to 13 meters. Meanwhile, gravity increased by 50 and 90 nms-2 in February and March, respectively. A first conclusion is that during these sudden floods, the pores and fine fissures were poorly connected with the enlarged fractures, cave, and conduits. With a rise of 13 meters in the water level and a 5% porosity, a gravity change of 250 nms-2 should have been expected. This moderate gravity variation suggests either a</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1985GeCoA..49..835N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1985GeCoA..49..835N"><span id="translatedtitle"><span class="hlt">Absolute</span> isotopic abundances of TI in meteorites</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Niederer, F. R.; Papanastassiou, D. A.; Wasserburg, G. J.</p> <p>1985-03-01</p> <p>The <span class="hlt">absolute</span> isotope abundance of Ti has been determined in Ca-Al-rich inclusions from the Allende and Leoville meteorites and in samples of whole meteorites. The <span class="hlt">absolute</span> Ti isotope abundances differ by a significant mass dependent isotope fractionation transformation from the previously reported abundances, which were normalized for fractionation using 46Ti/48Ti. Therefore, the <span class="hlt">absolute</span> compositions define distinct nucleosynthetic components from those previously identified or reflect the existence of significant mass dependent isotope fractionation in nature. The authors provide a general formalism for determining the possible isotope compositions of the exotic Ti from the measured composition, for different values of isotope fractionation in nature and for different mixing ratios of the exotic and normal components.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/371207','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/371207"><span id="translatedtitle">Molecular iodine <span class="hlt">absolute</span> frequencies. Final report</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sansonetti, C.J.</p> <p>1990-06-25</p> <p>Fifty specified lines of {sup 127}I{sub 2} were studied by Doppler-free frequency modulation spectroscopy. For each line the classification of the molecular transition was determined, hyperfine components were identified, and one well-resolved component was selected for precise determination of its <span class="hlt">absolute</span> frequency. In 3 cases, a nearby alternate line was selected for measurement because no well-resolved component was found for the specified line. <span class="hlt">Absolute</span> frequency determinations were made with an estimated uncertainty of 1.1 MHz by locking a dye laser to the selected hyperfine component and measuring its wave number with a high-precision Fabry-Perot wavemeter. For each line results of the <span class="hlt">absolute</span> measurement, the line classification, and a Doppler-free spectrum are given.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26478959','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26478959"><span id="translatedtitle">Stimulus probability effects in <span class="hlt">absolute</span> identification.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kent, Christopher; Lamberts, Koen</p> <p>2016-05-01</p> <p>This study investigated the effect of stimulus presentation probability on accuracy and response times in an <span class="hlt">absolute</span> identification task. Three schedules of presentation were used to investigate the interaction between presentation probability and stimulus position within the set. Data from individual participants indicated strong effects of presentation probability on both proportion correct and response times. The effects were moderated by the ubiquitous stimulus position effect. The accuracy and response time data were predicted by an exemplar-based model of perceptual cognition (Kent & Lamberts, 2005). The bow in discriminability was also attenuated when presentation probability for middle items was relatively high, an effect that will constrain future model development. The study provides evidence for item-specific learning in <span class="hlt">absolute</span> identification. Implications for other theories of <span class="hlt">absolute</span> identification are discussed. (PsycINFO Database Record PMID:26478959</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/6063303','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/6063303"><span id="translatedtitle"><span class="hlt">Absolute</span> calibration in vivo measurement systems</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kruchten, D.A.; Hickman, D.P.</p> <p>1991-02-01</p> <p>Lawrence Livermore National Laboratory (LLNL) is currently investigating a new method for obtaining <span class="hlt">absolute</span> calibration factors for radiation measurement systems used to measure internally deposited radionuclides in vivo. <span class="hlt">Absolute</span> calibration of in vivo measurement systems will eliminate the need to generate a series of human surrogate structures (i.e., phantoms) for calibrating in vivo measurement systems. The <span class="hlt">absolute</span> calibration of in vivo measurement systems utilizes magnetic resonance imaging (MRI) to define physiological structure, size, and composition. The MRI image provides a digitized representation of the physiological structure, which allows for any mathematical distribution of radionuclides within the body. Using Monte Carlo transport codes, the emission spectrum from the body is predicted. The in vivo measurement equipment is calibrated using the Monte Carlo code and adjusting for the intrinsic properties of the detection system. The calibration factors are verified using measurements of existing phantoms and previously obtained measurements of human volunteers. 8 refs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFM.T11C1892C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFM.T11C1892C"><span id="translatedtitle">The Geodynamic Origins of Western U.S. <span class="hlt">Topography</span>: Correlations and Speculations.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Coblentz, D.; van Wijk, J.; Phillips, S.; Karlstrom, K.; Chase, C.</p> <p>2008-12-01</p> <p>The <span class="hlt">topography</span> of the Earth's surface provides important information for regional and global geomorphic studies because it reflects the interplay between tectonic-associated processes of uplift and climate- associated processes of erosion. The <span class="hlt">topography</span> of the actively deforming western U.S. Cordillera is characterized by high relief and regionally high elevation, typically exceeding 1.5 km. Intriguingly, much of the high elevation coincides with thin or attenuated continental crust, necessitating topographic support by anomalous buoyancy of the mantle - suggesting that geodynamics responsible for the <span class="hlt">topography</span> in the Western U.S. has a significant component associated with deep sources in the upper mantle. In an attempt to sharpen our understanding of the underlying geodynamics, we present a quantitative comparison of three databases (<span class="hlt">topography</span>, geoid and Lg Q) that provide information about the geodynamics of the western U.S. at different depth scales. The unprecedented breadth and density of the USArray allows us to resolve lateral variations of 1-Hz Lg (a prominent seismic phase on most short period, regional distance seismograms along continental paths, resulting from the superposition of trapped, crustal shear waves) attenuation to 0.5 degrees over much of the western United States. In the Western U.S., Lg Q ranges from 60 to 550 and shows striking correlation with regional geology and <span class="hlt">topography</span>, with lowest Q associated with recent volcanic and geothermal activity, and active shear zones, and highest Q associated with older, stable crust, intrusives, and competent, topographically bounded blocks in the Basin and Range. Several areas - most notably Yellowstone, the margins of the Colorado Plateau, and the Aspen Anomaly - exhibit a strong correlation between the surface <span class="hlt">topography</span>, long-wavelength geoid anomalies and Lg Q and provide compelling support for the notion that many of the topographic features that characterize the Western U.S. are associated</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMDI33A2615I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMDI33A2615I"><span id="translatedtitle">A Global Study of Inner Core Boundary <span class="hlt">Topography</span> and its Temporal Variations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ibourichene, A.; Romanowicz, B. A.</p> <p>2015-12-01</p> <p>The inner core boundary (ICB) separates the solid inner core from the surrounding liquid outer core. Its detailed properties, such as its shape, the density jump across it or its <span class="hlt">topography</span> are key for understanding the <span class="hlt">dynamics</span> of the core and, ultimately, the generation and sustained character of the Earth's magnetic field. The determination of the ICB <span class="hlt">topography</span> and its variation with time could also enhance our understanding of the inner core growth and its past history.Seismology makes use of two phases to study the shallow inner core : the PKiKP, reflected at the ICB and the PKIKP, refracted into the inner core. The PKiKP/PKIKP amplitude ratio and the travel time residual of these phases characterize the vicinity of the ICB and may help constrain ICB <span class="hlt">topography</span>. Different studies propose various wavelengths for this <span class="hlt">topography</span>: from hundreds of meters to tens of kilometers. Several parameters can affect PKiKP/PKIKP amplitude ratios and the corresponding differential travel time, such as the quality factor of the shallow inner core, the density jump at the ICB, the geometry of the ray paths or even the reflection coefficient at the ICB. We present a global map of PKiKP/PKIKP amplitude ratios and differential travel times filtered in different pass-bands, with regional densification based, in particular, on the relatively short wavelength sampling afforded by large aperture broadband arrays, such as USArray, and discuss their spatial variability and interpretation in terms of ICB <span class="hlt">topography</span>, as appropriate.We also have assembled a catalog of high quality doublets which provide a reference for the stability of the measurements, and point to possible time variability of the <span class="hlt">topography</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20030067822&hterms=insulin&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dinsulin','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20030067822&hterms=insulin&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dinsulin"><span id="translatedtitle">Macromolecular <span class="hlt">Topography</span> Leaps into the Digital Age</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lovelace, J.; Bellamy, H.; Snell, E. H.; Borgstahl, G.</p> <p>2003-01-01</p> <p>A low-cost, real-time digital <span class="hlt">topography</span> system is under development which will replace x-ray film and nuclear emulsion plates. The imaging system is based on an inexpensive surveillance camera that offers a 1000x1000 array of 8 im square pixels, anti-blooming circuitry, and very quick read out. Currently, the system directly converts x-rays to an image with no phosphor. The system is small and light and can be easily adapted to work with other crystallographic equipment. Preliminary images have been acquired of cubic insulin at the NSLS x26c beam line. NSLS x26c was configured for unfocused monochromatic radiation. Six reflections were collected with stills spaced from 0.002 to 0.001 degrees apart across the entire oscillation range that the reflections were in diffracting condition. All of the reflections were rotated to the vertical to reduce Lorentz and beam related effects. This particular CCD is designed for short exposure applications (much less than 1 sec) and so has a relatively high dark current leading to noisy raw images. The images are processed to remove background and other system noise with a multi-step approach including the use of wavelets, histogram, and mean window filtering. After processing, animations were constructed with the corresponding reflection profile to show the diffraction of the crystal volume vs. the oscillation angle as well as composite images showing the parts of the crystal with the strongest diffraction for each reflection. The final goal is to correlate features seen in reflection profiles captured with fine phi slicing to those seen in the <span class="hlt">topography</span> images. With this development macromolecular <span class="hlt">topography</span> finally comes into the digital age.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26553885','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26553885"><span id="translatedtitle"><span class="hlt">Topography</span> Influences Adherent Cell Regulation of Osteoclastogenesis.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Nagasawa, M; Cooper, L F; Ogino, Y; Mendonca, D; Liang, R; Yang, S; Mendonca, G; Uoshima, K</p> <p>2016-03-01</p> <p>The importance of osteoclast-mediated bone resorption in the process of osseointegration has not been widely considered. In this study, cell culture was used to investigate the hypothesis that the function of implant-adherent bone marrow stromal cells (BMSCs) in osteoclastogenesis is influenced by surface <span class="hlt">topography</span>. BMSCs isolated from femur and tibia of Sprague-Dawley rats were seeded onto 3 types of titanium surfaces (smooth, micro, and nano) and a control surface (tissue culture plastic) with or without osteogenic supplements. After 3 to 14 d, conditioned medium (CM) was collected. Subsequently, rat bone marrow-derived macrophages (BMMs) were cultured in media supplemented with soluble receptor activator of NF-κB ligand (RANKL) and macrophage colony-stimulating factor (M-CSF) as well as BMSC CM from each of the 4 surfaces. Gene expression levels of soluble RANKL, osteoprotegerin, tumor necrosis factor α, and M-CSF in cultured BMSCs at different time points were measured by real-time polymerase chain reaction. The number of differentiated osteoclastic cells was determined after tartrate-resistant acid phosphatase staining. Analysis of variance and t test were used for statistical analysis. The expression of prominent osteoclast-promoting factors tumor necrosis factor α and M-CSF was increased by BMSCs cultured on both micro- and nanoscale titanium <span class="hlt">topographies</span> (P < 0.01). BMSC CM contained a heat-labile factor that increased BMMs osteoclastogenesis. CM from both micro- and nanoscale surface-adherent BMSCs increased the osteoclast number (P < 0.01). Difference in surface <span class="hlt">topography</span> altered BMSC phenotype and influenced BMM osteoclastogenesis. Local signaling by implant-adherent cells at the implant-bone interface may indirectly control osteoclastogenesis and bone accrual around endosseous implants. PMID:26553885</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AIPC.1367...29A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AIPC.1367...29A"><span id="translatedtitle">Precise Measurement of the <span class="hlt">Absolute</span> Fluorescence Yield</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ave, M.; Bohacova, M.; Daumiller, K.; Di Carlo, P.; di Giulio, C.; San Luis, P. Facal; Gonzales, D.; Hojvat, C.; Hörandel, J. R.; Hrabovsky, M.; Iarlori, M.; Keilhauer, B.; Klages, H.; Kleifges, M.; Kuehn, F.; Monasor, M.; Nozka, L.; Palatka, M.; Petrera, S.; Privitera, P.; Ridky, J.; Rizi, V.; D'Orfeuil, B. Rouille; Salamida, F.; Schovanek, P.; Smida, R.; Spinka, H.; Ulrich, A.; Verzi, V.; Williams, C.</p> <p>2011-09-01</p> <p>We present preliminary results of the <span class="hlt">absolute</span> yield of fluorescence emission in atmospheric gases. Measurements were performed at the Fermilab Test Beam Facility with a variety of beam particles and gases. <span class="hlt">Absolute</span> calibration of the fluorescence yield to 5% level was achieved by comparison with two known light sources--the Cherenkov light emitted by the beam particles, and a calibrated nitrogen laser. The uncertainty of the energy scale of current Ultra-High Energy Cosmic Rays experiments will be significantly improved by the AIRFLY measurement.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.usgs.gov/ds/393/','USGSPUBS'); return false;" href="http://pubs.usgs.gov/ds/393/"><span id="translatedtitle">EAARL Coastal <span class="hlt">Topography</span> - Sandy Hook 2007</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Nayegandhi, Amar; Brock, John C.; Wright, C. Wayne; Stevens, Sara; Yates, Xan; Bonisteel, Jamie M.</p> <p>2008-01-01</p> <p>These remotely sensed, geographically referenced elevation measurements of Lidar-derived <span class="hlt">topography</span> were produced as a collaborative effort between the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL; the National Park Service (NPS), Northeast Coastal and Barrier Network, Kingston, RI; and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of Gateway National Recreation Area's Sandy Hook Unit in New Jersey, acquired on May 16, 2007. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL) was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) Lidar designed to map near-shore bathymetry, <span class="hlt">topography</span>, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers and an integrated miniature digital inertial measurement unit, which provide for submeter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a Lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal <span class="hlt">topography</span> within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013SuTMP...1a0201L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013SuTMP...1a0201L"><span id="translatedtitle">Welcome to Surface <span class="hlt">Topography</span>: Metrology and Properties</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Leach, Richard</p> <p>2013-11-01</p> <p>I am delighted to welcome readers to this inaugural issue of Surface <span class="hlt">Topography</span>: Metrology and Properties (STMP). In these days of citation indexes and academic reviews, it is a tough, and maybe a brave, job to start a new journal. But the subject area has never been more active and we are seeing genuine breakthroughs in the use of surfaces to control functional performance. Most manufactured parts rely on some form of control of their surface characteristics. The surface is usually defined as that feature on a component or device, which interacts with either the environment in which it is housed (or in which the device operates), or with another surface. The surface <span class="hlt">topography</span> and material characteristics of a part can affect how fluids interact with it, how the part looks and feels and how two bearing parts will slide together. The need to control, and hence measure, surface features is becoming increasingly important as we move into a miniaturized world. Surface features can become the dominant functional features of a part and may become large in comparison to the overall size of an object. Research into surface texture measurement and characterization has been carried out for over a century and is now more active than ever, especially as new areal surface texture specification standards begin to be introduced. The range of disciplines for which the function of a surface relates to its <span class="hlt">topography</span> is very diverse; from metal sheet manufacturing to art restoration, from plastic electronics to forensics. Until now, there has been no obvious publishing venue to bring together all these applications with the underlying research and theory, or to unite those working in academia with engineering and industry. Hence the creation of Surface <span class="hlt">Topography</span>: Metrology and Properties . STMP will publish the best work being done across this broad discipline in one journal, helping researchers to share common themes and highlighting and promoting the extraordinary benefits this</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/983262','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/983262"><span id="translatedtitle">Carbon contamination <span class="hlt">topography</span> analysis of EUV masks</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Fan, Y.-J.; Yankulin, L.; Thomas, P.; Mbanaso, C.; Antohe, A.; Garg, R.; Wang, Y.; Murray, T.; Wuest, A.; Goodwin, F.; Huh, S.; Cordes, A.; Naulleau, P.; Goldberg, K. A.; Mochi, I.; Gullikson, E.; Denbeaux, G.</p> <p>2010-03-12</p> <p>The impact of carbon contamination on extreme ultraviolet (EUV) masks is significant due to throughput loss and potential effects on imaging performance. Current carbon contamination research primarily focuses on the lifetime of the multilayer surfaces, determined by reflectivity loss and reduced throughput in EUV exposure tools. However, contamination on patterned EUV masks can cause additional effects on absorbing features and the printed images, as well as impacting the efficiency of cleaning process. In this work, several different techniques were used to determine possible contamination <span class="hlt">topography</span>. Lithographic simulations were also performed and the results compared with the experimental data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014NatCo...5E4507R&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014NatCo...5E4507R&link_type=ABSTRACT"><span id="translatedtitle">Reconstituting ring-rafts in bud-mimicking <span class="hlt">topography</span> of model membranes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ryu, Yong-Sang; Lee, In-Ho; Suh, Jeng-Hun; Park, Seung Chul; Oh, Soojung; Jordan, Luke R.; Wittenberg, Nathan J.; Oh, Sang-Hyun; Jeon, Noo Li; Lee, Byoungho; Parikh, Atul N.; Lee, Sin-Doo</p> <p>2014-07-01</p> <p>During vesicular trafficking and release of enveloped viruses, the budding and fission processes <span class="hlt">dynamically</span> remodel the donor cell membrane in a protein- or a lipid-mediated manner. In all cases, in addition to the generation or relief of the curvature stress, the buds recruit specific lipids and proteins from the donor membrane through restricted diffusion for the development of a ring-type raft domain of closed topology. Here, by reconstituting the bud <span class="hlt">topography</span> in a model membrane, we demonstrate the preferential localization of cholesterol- and sphingomyelin-enriched microdomains in the collar band of the bud-neck interfaced with the donor membrane. The geometrical approach to the recapitulation of the <span class="hlt">dynamic</span> membrane reorganization, resulting from the local radii of curvatures from nanometre-to-micrometre scales, offers important clues for understanding the active roles of the bud <span class="hlt">topography</span> in the sorting and migration machinery of key signalling proteins involved in membrane budding.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4124864','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4124864"><span id="translatedtitle">Reconstituting ring-rafts in bud-mimicking <span class="hlt">topography</span> of model membranes</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ryu, Yong-Sang; Lee, In-Ho; Suh, Jeng-Hun; Park, Seung Chul; Oh, Soojung; Jordan, Luke R.; Wittenberg, Nathan J.; Oh, Sang-Hyun; Jeon, Noo Li; Lee, Byoungho; Parikh, Atul N.; Lee, Sin-Doo</p> <p>2014-01-01</p> <p>During vesicular trafficking and release of enveloped viruses, the budding and fission processes <span class="hlt">dynamically</span> remodel the donor cell membrane in a protein- or a lipid-mediated manner. In all cases, in addition to the generation or relief of the curvature stress, the buds recruit specific lipids and proteins from the donor membrane through restricted diffusion for the development of a ring-type raft domain of closed topology. Here, by reconstituting the bud <span class="hlt">topography</span> in a model membrane, we demonstrate the preferential localization of cholesterol- and sphingomyelin-enriched microdomains in the collar band of the bud-neck interfaced with the donor membrane. The geometrical approach to the recapitulation of the <span class="hlt">dynamic</span> membrane reorganization, resulting from the local radii of curvatures from nanometre-to-micrometre scales, offers important clues for understanding the active roles of the bud <span class="hlt">topography</span> in the sorting and migration machinery of key signalling proteins involved in membrane budding. PMID:25058275</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25058275','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25058275"><span id="translatedtitle">Reconstituting ring-rafts in bud-mimicking <span class="hlt">topography</span> of model membranes.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ryu, Yong-Sang; Lee, In-Ho; Suh, Jeng-Hun; Park, Seung Chul; Oh, Soojung; Jordan, Luke R; Wittenberg, Nathan J; Oh, Sang-Hyun; Jeon, Noo Li; Lee, Byoungho; Parikh, Atul N; Lee, Sin-Doo</p> <p>2014-01-01</p> <p>During vesicular trafficking and release of enveloped viruses, the budding and fission processes <span class="hlt">dynamically</span> remodel the donor cell membrane in a protein- or a lipid-mediated manner. In all cases, in addition to the generation or relief of the curvature stress, the buds recruit specific lipids and proteins from the donor membrane through restricted diffusion for the development of a ring-type raft domain of closed topology. Here, by reconstituting the bud <span class="hlt">topography</span> in a model membrane, we demonstrate the preferential localization of cholesterol- and sphingomyelin-enriched microdomains in the collar band of the bud-neck interfaced with the donor membrane. The geometrical approach to the recapitulation of the <span class="hlt">dynamic</span> membrane reorganization, resulting from the local radii of curvatures from nanometre-to-micrometre scales, offers important clues for understanding the active roles of the bud <span class="hlt">topography</span> in the sorting and migration machinery of key signalling proteins involved in membrane budding. PMID:25058275</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1998Natur.392..696C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1998Natur.392..696C"><span id="translatedtitle">Surface <span class="hlt">topography</span> dependence of biomolecular hydrophobic hydration</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cheng, Yuen-Kit; Rossky, Peter J.</p> <p>1998-04-01</p> <p>Many biomolecules are characterized by surfaces containing extended nonpolar regions, and the aggregation and subsequent removal of such surfaces from water is believed to play a critical role in the biomolecular assembly in cells. A better understanding of the hydrophobic hydration of biomolecules may therefore yield new insights into intracellular assembly. Conventional views hold that the hydration shell of small hydrophobic solutes is clathrate-like, characterized by local cage-like hydrogen-bonding structures and a distinct loss in entropy. The hydration of extended nonpolar planar surfaces, however, appears to involve structures that are orientationally inverted relative to clathrate-like hydration shells,, with unsatisfied hydrogen bonds that are directed towards the hydrophobic surface. Here we present computer simulations of the interaction between the polypeptide melittin and water that demonstrate that the two different hydration structures also exist near a biomolecular surface. We find that the two structures are distinguished by a substantial difference in the water-water interaction enthalpy, and that their relative contributions depend strongly on the surface <span class="hlt">topography</span> of the melittin molecule: clathrate-like structures dominate near convex surface patches, whereas the hydration shell near flat surfaces fluctuates between clathrate-like and less-ordered or inverted structures. The strong influence of surface <span class="hlt">topography</span> on the structure and free energy of hydrophobic hydration is likely to hold in general, and will be particularly important for the many biomolecules whose surfaces contain convex patches, deep or shallow concave grooves and roughly planar areas.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.usgs.gov/of/2008/1326/','USGSPUBS'); return false;" href="http://pubs.usgs.gov/of/2008/1326/"><span id="translatedtitle">EAARL <span class="hlt">Topography</span>-Colonial National Historical Park</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Brock, John C.; Wright, C. Wayne; Nayegandhi, Amar; Stevens, Sara; Travers, Laurinda J.</p> <p>2008-01-01</p> <p>These Lidar-derived <span class="hlt">topography</span> maps were produced as a collaborative effort between the U.S. Geological Survey (USGS) Coastal and Marine Geology Program, Florida Integrated Science Center (FISC) St. Petersburg, the National Park Service (NPS) Inventory and Monitoring Program, Northeast Coastal and Barrier Network, and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility. One objective of this research is to create techniques to survey coral reefs, barrier islands, and various nearshore coastal environments 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 <span class="hlt">topography</span> 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 coastal resource managers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1983SPIE..361..111T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1983SPIE..361..111T"><span id="translatedtitle">Analysis Of Scoliosis By Back Shape <span class="hlt">Topography</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Turner-Smith, Alan R.; Harris, John D.</p> <p>1983-07-01</p> <p>The use of surface <span class="hlt">topography</span> for the assessment of scoliotic deformity in the clinic depends firstly on the quality of measures which reliably characterise deformity of the back, and secondly on the ease and speed with which these measures can be applied. A method of analysis of back shape measurements is presented which can be applied to any topographic measurement system. Measures presented are substantially independent of minor changes in the patient's posture in rotation and flexion from one clinic to the next, and yet sensitive enough to indicate significant improvement or degeneration of the disease. The presentation shows (1) horizontal cross-sections at ten levels up the back from sacrum to vertebra prominens, (2) angles of rotation of the surface over a small region about the spine, (3) three vertical profiles following the line of the spine, and (4) measures of maximum kyphosis and lordosis. Dependence on the operator has been reduced to a minimum. Extreme care in positioning the patient is unnecessary and those spinous processes which are easily palpable, the vertebra prominens and the two dimples over the posterior superior iliac spines are marked. Analysis proceeds entirely automatically once the basic shape data have been supplied. Applications of the technique to indirect moire <span class="hlt">topography</span> and a television topographic measurement system are described.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26164456','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26164456"><span id="translatedtitle">Nicotinic alteration of functional thalamocortical <span class="hlt">topography</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lee, Charles C; Yanagawa, Yuchio; Imaizumi, Kazuo</p> <p>2015-08-19</p> <p>The thalamocortical pathways form highly topographic connections from the primary sensory thalamic nuclei to the primary cortical areas. The synaptic properties of these thalamocortical connections are modifiable by activation from various neuromodulators, such as acetylcholine. Cholinergic activation can alter functional properties in both the developing and the mature nervous system. Moreover, environmental factors, such as nicotine, can activate these receptors, although the circuit-level alterations resulting from such nicotinic activation of sensory neural circuits remain largely unexplored. Therefore, we examined alterations to the functional <span class="hlt">topography</span> of thalamocortical circuits in the developing sensory pathways of the mouse. Photostimulation by uncaging of glutamate was used to map these functional thalamocortical alterations in response to nicotinic receptor activation. As a result, we found that activation of forebrain nicotinic acetylcholine receptors results in an expansion and enhancement of functional thalamocortical <span class="hlt">topographies</span> as assessed in brain slice preparations using laser-scanning photostimulation by uncaging of glutamate. These physiological changes were correlated with the neuroanatomical expression of nicotinic acetylcholine receptor subtypes (α7 and β2). These circuit-level alterations may provide a neural substrate underlying the plastic development and reshaping of thalamocortical circuitry in response to nicotinic receptor activation. PMID:26164456</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SuTMP...3c5004H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SuTMP...3c5004H"><span id="translatedtitle">Uncertainty in measurement of surface <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Haitjema, Han</p> <p>2015-09-01</p> <p>The 2.5-dimensional (2.5D) roughness parameters were standardized in 2012. With their increasing use in science and industry, the request for traceability and uncertainty evaluation for these parameters follows logically. This paper gives an overview of the problems and possibilities that appear when uncertainties have to be associated with values that are derived from a measured surface <span class="hlt">topography</span>, such as the Ra-value of a periodic specimen, the RSm value of a type-D standard, and the Sa-value of a single cutoff length of a type D standard. It is shown that straightforward implementation of the methods described in the ‘Guide to the Expression of Uncertainty in Measurement’ (GUM) leads to impossible and impracticable equations because of the correlations between some millions of measurement points. A practical solution is found by considering the main aspects of uncertainty, as these are given in the recent ISO 25178 standards series, and applying these to a measured surface <span class="hlt">topography</span> as a whole.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/927741','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/927741"><span id="translatedtitle"><span class="hlt">Absolute</span> partial photoionization cross sections of ozone.</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Berkowitz, J.; Chemistry</p> <p>2008-04-01</p> <p>Despite the current concerns about ozone, <span class="hlt">absolute</span> partial photoionization cross sections for this molecule in the vacuum ultraviolet (valence) region have been unavailable. By eclectic re-evaluation of old/new data and plausible assumptions, such cross sections have been assembled to fill this void.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=VALUE+AND+ABSOLUTE&pg=2&id=EJ726176','ERIC'); return false;" href="http://eric.ed.gov/?q=VALUE+AND+ABSOLUTE&pg=2&id=EJ726176"><span id="translatedtitle">Solving <span class="hlt">Absolute</span> Value Equations Algebraically and Geometrically</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Shiyuan, Wei</p> <p>2005-01-01</p> <p>The way in which students can improve their comprehension by understanding the geometrical meaning of algebraic equations or solving algebraic equation geometrically is described. Students can experiment with the conditions of the <span class="hlt">absolute</span> value equation presented, for an interesting way to form an overall understanding of the concept.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=VALUE+AND+ABSOLUTE&id=EJ945042','ERIC'); return false;" href="http://eric.ed.gov/?q=VALUE+AND+ABSOLUTE&id=EJ945042"><span id="translatedtitle">Teaching <span class="hlt">Absolute</span> Value Inequalities to Mature Students</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Sierpinska, Anna; Bobos, Georgeana; Pruncut, Andreea</p> <p>2011-01-01</p> <p>This paper gives an account of a teaching experiment on <span class="hlt">absolute</span> value inequalities, whose aim was to identify characteristics of an approach that would realize the potential of the topic to develop theoretical thinking in students enrolled in prerequisite mathematics courses at a large, urban North American university. The potential is…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=loudness&pg=4&id=EJ933808','ERIC'); return false;" href="http://eric.ed.gov/?q=loudness&pg=4&id=EJ933808"><span id="translatedtitle">Increasing Capacity: Practice Effects in <span class="hlt">Absolute</span> Identification</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Dodds, Pennie; Donkin, Christopher; Brown, Scott D.; Heathcote, Andrew</p> <p>2011-01-01</p> <p>In most of the long history of the study of <span class="hlt">absolute</span> identification--since Miller's (1956) seminal article--a severe limit on performance has been observed, and this limit has resisted improvement even by extensive practice. In a startling result, Rouder, Morey, Cowan, and Pfaltz (2004) found substantially improved performance with practice in the…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=mathematics+AND+education&pg=5&id=EJ1070973','ERIC'); return false;" href="http://eric.ed.gov/?q=mathematics+AND+education&pg=5&id=EJ1070973"><span id="translatedtitle">On Relative and <span class="hlt">Absolute</span> Conviction in Mathematics</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Weber, Keith; Mejia-Ramos, Juan Pablo</p> <p>2015-01-01</p> <p>Conviction is a central construct in mathematics education research on justification and proof. In this paper, we claim that it is important to distinguish between <span class="hlt">absolute</span> conviction and relative conviction. We argue that researchers in mathematics education frequently have not done so and this has lead to researchers making unwarranted claims…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=kowalski&pg=7&id=EJ753903','ERIC'); return false;" href="http://eric.ed.gov/?q=kowalski&pg=7&id=EJ753903"><span id="translatedtitle"><span class="hlt">Absolute</span> Points for Multiple Assignment Problems</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Adlakha, V.; Kowalski, K.</p> <p>2006-01-01</p> <p>An algorithm is presented to solve multiple assignment problems in which a cost is incurred only when an assignment is made at a given cell. The proposed method recursively searches for single/group <span class="hlt">absolute</span> points to identify cells that must be loaded in any optimal solution. Unlike other methods, the first solution is the optimal solution. The…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APS..MARF45011M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..MARF45011M"><span id="translatedtitle">Nonequilibrium equalities in <span class="hlt">absolutely</span> irreversible processes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Murashita, Yuto; Funo, Ken; Ueda, Masahito</p> <p>2015-03-01</p> <p>Nonequilibrium equalities have attracted considerable attention in the context of statistical mechanics and information thermodynamics. Integral nonequilibrium equalities reveal an ensemble property of the entropy production σ as <e-σ > = 1 . Although nonequilibrium equalities apply to rather general nonequilibrium situations, they break down in <span class="hlt">absolutely</span> irreversible processes, where the forward-path probability vanishes and the entropy production diverges. We identify the mathematical origins of this inapplicability as the singularity of probability measure. As a result, we generalize conventional integral nonequilibrium equalities to <span class="hlt">absolutely</span> irreversible processes as <e-σ > = 1 -λS , where λS is the probability of the singular part defined based on Lebesgue's decomposition theorem. The acquired equality contains two physical quantities related to irreversibility: σ characterizing ordinary irreversibility and λS describing <span class="hlt">absolute</span> irreversibility. An inequality derived from the obtained equality demonstrates the <span class="hlt">absolute</span> irreversibility leads to the fundamental lower bound on the entropy production. We demonstrate the validity of the obtained equality for a simple model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=effect&pg=3&id=EJ1099263','ERIC'); return false;" href="http://eric.ed.gov/?q=effect&pg=3&id=EJ1099263"><span id="translatedtitle">Stimulus Probability Effects in <span class="hlt">Absolute</span> Identification</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Kent, Christopher; Lamberts, Koen</p> <p>2016-01-01</p> <p>This study investigated the effect of stimulus presentation probability on accuracy and response times in an <span class="hlt">absolute</span> identification task. Three schedules of presentation were used to investigate the interaction between presentation probability and stimulus position within the set. Data from individual participants indicated strong effects of…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23669658','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23669658"><span id="translatedtitle">Precision <span class="hlt">absolute</span> positional measurement of laser beams.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Fitzsimons, Ewan D; Bogenstahl, Johanna; Hough, James; Killow, Christian J; Perreur-Lloyd, Michael; Robertson, David I; Ward, Henry</p> <p>2013-04-20</p> <p>We describe an instrument which, coupled with a suitable coordinate measuring machine, facilitates the <span class="hlt">absolute</span> measurement within the machine frame of the propagation direction of a millimeter-scale laser beam to an accuracy of around ±4 μm in position and ±20 μrad in angle. PMID:23669658</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.usgs.gov/ds/384/','USGSPUBS'); return false;" href="http://pubs.usgs.gov/ds/384/"><span id="translatedtitle">EAARL Coastal <span class="hlt">Topography</span> - Northern Gulf of Mexico</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Nayegandhi, Amar; Brock, John C.; Sallenger, Abby; Wright, C. Wayne; Travers, Laurinda J.; Lebonitte, James</p> <p>2008-01-01</p> <p>These remotely sensed, geographically referenced elevation measurements of Lidar-derived coastal <span class="hlt">topography</span> were produced as a collaborative effort between the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. One objective of this research is to create techniques to survey areas for the purposes of geomorphic change studies following major storm events. The USGS Coastal and Marine Geology Program's National Assessment of Coastal Change Hazards project is a multi-year undertaking to identify and quantify the vulnerability of U.S. shorelines to coastal change hazards such as effects of severe storms, sea-level rise, and shoreline erosion and retreat. Airborne Lidar surveys conducted during periods of calm weather are compared to surveys collected following extreme storms in order to quantify the resulting coastal change. Other applications of high-resolution <span class="hlt">topography</span> include habitat mapping, ecological monitoring, volumetric change detection, and event assessment. The purpose of this project is to provide highly detailed and accurate datasets of the northern Gulf of Mexico coastal areas, acquired on September 19, 2004, immediately following Hurricane Ivan. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Airborne Advanced Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532 nanometer) Lidar designed to map near-shore bathymetry, <span class="hlt">topography</span>, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking RGB (red-green-blue) digital camera, a high-resolution multi</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1994Icar..112...27R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1994Icar..112...27R"><span id="translatedtitle">A 360-degree and -order model of Venus <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rappaport, Nicole; Plaut, Jeffrey J.</p> <p>1994-11-01</p> <p>This report presents the most recent spherical harmonic <span class="hlt">topography</span> model of Venus developed at Jet Propulsion Laboratory. It was produced by a spherical harmonic analysis of the most complete set of Magellan altimetry data, augmented by Pioneer Venus and Venera data. The harmonic coefficients of the <span class="hlt">topography</span> were computed to degree and order 360. Compared to previous <span class="hlt">topography</span> models, this one has the highest correlation with the gravity field of Venus.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20060036111&hterms=360+degree&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DTitle%26N%3D0%26No%3D30%26Ntt%3D360%2Bdegree','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20060036111&hterms=360+degree&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DTitle%26N%3D0%26No%3D30%26Ntt%3D360%2Bdegree"><span id="translatedtitle">A 360-Degree and -Order Model of Venus <span class="hlt">Topography</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rappaport, Nicole; Plaut, Jeffry J.</p> <p>1996-01-01</p> <p>This report presents the most recent spherical harmonic <span class="hlt">topography</span> model of Venus developed at Jet Propulsion Laboratory. It was produced by a spherical harmonic analysis of the most complete set of Magellan altimetry data, augmented by Pioneer Venus and Venera data. The harmonic coefficients of the <span class="hlt">topography</span> were computed to degree and order 360. Compared to previous <span class="hlt">topography</span> models, this one has the highest correlation with the gravity field of Venus.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950053349&hterms=360+degree&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DTitle%26N%3D0%26No%3D30%26Ntt%3D360%2Bdegree','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950053349&hterms=360+degree&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DTitle%26N%3D0%26No%3D30%26Ntt%3D360%2Bdegree"><span id="translatedtitle">A 360-degree and -order model of Venus <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rappaport, Nicole; Plaut, Jeffrey J.</p> <p>1994-01-01</p> <p>This report presents the most recent spherical harmonic <span class="hlt">topography</span> model of Venus developed at Jet Propulsion Laboratory. It was produced by a spherical harmonic analysis of the most complete set of Magellan altimetry data, augmented by Pioneer Venus and Venera data. The harmonic coefficients of the <span class="hlt">topography</span> were computed to degree and order 360. Compared to previous <span class="hlt">topography</span> models, this one has the highest correlation with the gravity field of Venus.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20100033697','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20100033697"><span id="translatedtitle">STS-99 Shuttle Radar <span class="hlt">Topography</span> Mission Stability and Control</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hamelin, Jennifer L.; Jackson, Mark C.; Kirchwey, Christopher B.; Pileggi, Roberto A.</p> <p>2001-01-01</p> <p>The Shuttle Radar <span class="hlt">Topography</span> Mission (SRTM) flew aboard Space Shuttle Endeavor February 2000 and used interferometry to map 80% of the Earth's landmass. SRTM employed a 200-foot deployable mast structure to extend a second antenna away from the main antenna located in the Shuttle payload bay. Mapping requirements demanded precision pointing and orbital trajectories from the Shuttle on-orbit Flight Control System (PCS). Mast structural <span class="hlt">dynamics</span> interaction with the FCS impacted stability and performance of the autopilot for attitude maneuvers and pointing during mapping operations. A damper system added to ensure that mast tip motion remained with in the limits of the outboard antenna tracking system while mapping also helped to mitigate structural <span class="hlt">dynamic</span> interaction with the FCS autopilot. Late changes made to the payload damper system, which actually failed on-orbit, required a redesign and verification of the FCS autopilot filtering schemes necessary to ensure rotational control stability. In-flight measurements using three sensors were used to validate models and gauge the accuracy and robustness of the pre-mission notch filter design.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.S42C..05M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.S42C..05M"><span id="translatedtitle">Combined Use of <span class="hlt">Absolute</span> and Differential Seismic Arrival Time Data to Improve <span class="hlt">Absolute</span> Event Location</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Myers, S.; Johannesson, G.</p> <p>2012-12-01</p> <p>Arrival time measurements based on waveform cross correlation are becoming more common as advanced signal processing methods are applied to seismic data archives and real-time data streams. Waveform correlation can precisely measure the time difference between the arrival of two phases, and differential time data can be used to constrain relative location of events. <span class="hlt">Absolute</span> locations are needed for many applications, which generally requires the use of <span class="hlt">absolute</span> time data. Current methods for measuring <span class="hlt">absolute</span> time data are approximately two orders of magnitude less precise than differential time measurements. To exploit the strengths of both <span class="hlt">absolute</span> and differential time data, we extend our multiple-event location method Bayesloc, which previously used <span class="hlt">absolute</span> time data only, to include the use of differential time measurements that are based on waveform cross correlation. Fundamentally, Bayesloc is a formulation of the joint probability over all parameters comprising the multiple event location system. The Markov-Chain Monte Carlo method is used to sample from the joint probability distribution given arrival data sets. The differential time component of Bayesloc includes scaling a stochastic estimate of differential time measurement precision based the waveform correlation coefficient for each datum. For a regional-distance synthetic data set with <span class="hlt">absolute</span> and differential time measurement error of 0.25 seconds and 0.01 second, respectively, epicenter location accuracy is improved from and average of 1.05 km when solely <span class="hlt">absolute</span> time data are used to 0.28 km when <span class="hlt">absolute</span> and differential time data are used jointly (73% improvement). The improvement in <span class="hlt">absolute</span> location accuracy is the result of conditionally limiting <span class="hlt">absolute</span> location probability regions based on the precise relative position with respect to neighboring events. Bayesloc estimates of data precision are found to be accurate for the synthetic test, with <span class="hlt">absolute</span> and differential time measurement</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22280530','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22280530"><span id="translatedtitle">Origin of bending in uncoated microcantilever - Surface <span class="hlt">topography</span>?</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lakshmoji, K.; Prabakar, K.; Tripura Sundari, S. Jayapandian, J.; Tyagi, A. K.; Sundar, C. S.</p> <p>2014-01-27</p> <p>We provide direct experimental evidence to show that difference in surface <span class="hlt">topography</span> on opposite sides of an uncoated microcantilever induces bending, upon exposure to water molecules. Examination on opposite sides of the microcantilever by atomic force microscopy reveals the presence of localized surface features on one side, which renders the induced stress non-uniform. Further, the root mean square inclination angle characterizing the surface <span class="hlt">topography</span> shows a difference of 73° between the opposite sides. The absence of deflection in another uncoated microcantilever having similar surface <span class="hlt">topography</span> confirms that in former microcantilever bending is indeed induced by differences in surface <span class="hlt">topography</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19770054895&hterms=ferrari&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dferrari','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19770054895&hterms=ferrari&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dferrari"><span id="translatedtitle">A harmonic analysis of lunar <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bills, B. G.; Ferrari, A. J.</p> <p>1977-01-01</p> <p>A global lunar topographic map has been derived from existing earth-based and orbital observations supplemented in areas without data by a linear autocovariance predictor. Of 2592 bins, each 5 deg square, 1380 (64.7% by area) contain at least one measurement. A spherical harmonic analysis to degree 12 yields a mean radius of 1737.53 plus or minus 0.03 km (formal standard error) and an offset of the center of figure of 1.98 plus or minus 0.06 km toward (19 plus or minus 2) deg S, (194 plus or minus 1) deg E. A Bouguer gravity map, derived from a 12-degree free-air gravity model and the present <span class="hlt">topography</span> data, is presented for an elevation of 100 km above the mean surface. It is confirmed that the low-degree gravity harmonics are determined primarily by surface height variations and only secondarily by lateral density variations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/12543141','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/12543141"><span id="translatedtitle">A new method for mapping macromolecular <span class="hlt">topography</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Mezei, Mihaly</p> <p>2003-03-01</p> <p>A new method, using circular variance, is introduced for mapping macromolecular <span class="hlt">topography</span>. Circular variance, generally used to measures angular spread, can be used to characterize of molecular structures based on a simple idea. It will be shown that the circular variance of vectors drawn from some origin to a set of points is well correlated with the degree to which that origin is inside/outside the chosen points. In addition, it has continuous derivatives that are also easy to compute. This concept will be shown to be useful for: (i) distinguishing between atoms near the surface of a macromolecule and those in either the deep interior or remote exterior; (ii) identifying invaginations (even shallow ones); and (iii) detecting linker regions that interconnect two domains. PMID:12543141</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1983SPIE..361..107D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1983SPIE..361..107D"><span id="translatedtitle">Measurement Of Kyphosis Using Moire <span class="hlt">Topography</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Drerup, Burkhard</p> <p>1983-07-01</p> <p>Contour line patterns, as they are produced by moire <span class="hlt">topography</span> are dependent on position, posture and body shape of the patient. For all medical applications data are needed, which are only dependent on shape and posture and which therefore are independent of positioning. The measurement of the kyphotic angle from topograms can be performed to meet these requirements and to yield results, which are independent of positioning. Different techniques for measuring this angle are discussed. Digitization and reconstruction of profiles from moire topograms are presented. In order to get reproducible results, landmarks are needed on the body surface. Landmarks may be found either by palpation or by analytical investigation of the back shape. Here, the inflectional points of the sagittal back profile are taken as intrinsic landmarks. Their relation to anatomical landmarks, which are found e.g. by palpation, is studied.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19930005783&hterms=Alfred+Wegener&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DAlfred%2BWegener','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19930005783&hterms=Alfred+Wegener&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DAlfred%2BWegener"><span id="translatedtitle">Assimilation of altimeter <span class="hlt">topography</span> into oceanic models</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Demey, Pierre; Menard, Yves; Pinardi, Nadia; Schroeter, J.; Verron, J.</p> <p>1991-01-01</p> <p>The primary goals of the authors are to build an intuition for assimilation techniques and to investigate the impact of variable altimeter <span class="hlt">topography</span> on simple or complex oceanic models. In particular, applying various techniques and sensitivity studies to model and data constraints plays a key role. We are starting to use quasi-geostrophic, semigeostrophic, and primitive-equation (PE) models and to test the schemes in regions of interest to the World Ocean Circulation Experiment (WOCE), as well as in the northeast Atlantic and the Mediterranean. The impact of scatterometer wind forcing on the results is also investigated. The use of Geosat, European Remote Sensing satellite (ERS-1), and TOPEX/POSEIDON altimetry data is crucial in fine tuning the models and schemes to the selected areas of interest.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19900065452&hterms=herbert+land&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dherbert%2Bland','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19900065452&hterms=herbert+land&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dherbert%2Bland"><span id="translatedtitle">Australian <span class="hlt">topography</span> from Seasat overland altimetry</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Frey, Herbert; Brenner, Anita C.</p> <p>1990-01-01</p> <p>Retracking of overland returns from the Seasat altimeter using algorithms originally developed for recovering elevations over ice has led to the successful recovery of high quality continental <span class="hlt">topography</span> over Australia and other continents. Cross-over analysis both before and after orbit adjustment shows the altimetric data over land to have a 2-3 m quality. Direct comparison of gridded Seasat data with surface data re-averaged in the same way shows excellent agreement except where Seasat data are sparse, due either to poor track spacing or to dropouts caused by loss of tracker lock over steeply sloping ground. These results suggest that useful topographic data can be derived from Seasat and the more recent Geosat altimeters for parts of the world where surface data are few or of poor quality.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.usgs.gov/of/2006/1118/','USGSPUBS'); return false;" href="http://pubs.usgs.gov/of/2006/1118/"><span id="translatedtitle">EAARL submarine <span class="hlt">topography</span>: Biscayne National Park</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Brock, John C.; Wright, C. Wayne; Patterson, Matt; Nayegandhi, Amar; Patterson, Judd; Harris, Melanie S.; Mosher, Lance</p> <p>2006-01-01</p> <p>This lidar-derived submarine <span class="hlt">topography</span> map was produced as a collaborative effort between the U.S. Geological Survey (USGS) Coastal and Marine Geology Program, National Park Service (NPS) South Florida/Caribbean 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 for the purposes of habitat mapping, ecological monitoring, change detection, and event assessment (for example: bleaching, hurricanes, disease outbreaks). 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 water depth and conducting 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 managers of coastal tropical habitats.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.usgs.gov/of/2006/1244/','USGSPUBS'); return false;" href="http://pubs.usgs.gov/of/2006/1244/"><span id="translatedtitle">EAARL <span class="hlt">topography</span>: Dry Tortugas National Park</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Brock, John C.; Wright, C. Wayne; Patterson, Matt; Nayegandhi, Amar; Patterson, Judd</p> <p>2008-01-01</p> <p>This lidar-derived submarine <span class="hlt">topography</span> map was produced as a collaborative effort between the U.S. Geological Survey (USGS) Coastal and Marine Geology Program, National Park Service (NPS) South Florida/Caribbean 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 for the purposes of habitat mapping, ecological monitoring, change detection, ad event assessment (for example: bleaching, hurricanes, disease outbreaks). 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 water depth and conducting 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 managers of coastal tropical habitats.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.usgs.gov/of/2007/1007/','USGSPUBS'); return false;" href="http://pubs.usgs.gov/of/2007/1007/"><span id="translatedtitle">EAARL <span class="hlt">topography</span>: Fire Island National Seashore</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Brock, John C.; Wright, C. Wayne; Patterson, Matt; Nayagandhi, Amar; Patterson, Judd</p> <p>2007-01-01</p> <p>This Web site contains 31 LIDAR-derived first return <span class="hlt">topography</span> maps and GIS files for Fire Island National Seashore. These lidar-derived topographic maps were produced as a collaborative effort between the U.S. Geological Survey (USGS) Coastal and Marine Geology Program, the National Park Service (NPS), Northeast Coastal and Barrier Network, Inventory and Monitoring Program, and the National Aeronautics and Space Administration (NASA) Wallops Flight Facility. The aims of the partnership that created this product are to develop advanced survey techniques for mapping barrier island geomorphology and habitats, and to enable the monitoring of ecological and geological change within National Seashores. This product is based on data from an innovative airborne lidar instrument under development at the NASA Wallops Flight Facility, the NASA Experimental Advanced Airborne Research Lidar (EAARL).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5808031','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5808031"><span id="translatedtitle">Bedrock <span class="hlt">topography</span> beneath the Red Lake peatlands</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Miller, P.; Shaw, G.H. . Geology Dept.); Glaser, P. . Limnological Research Center); Siegel, D. . Dept. of Geology)</p> <p>1992-01-01</p> <p>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 <span class="hlt">topography</span> 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 <span class="hlt">topography</span> 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012SPIE.8533E..0GN','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012SPIE.8533E..0GN"><span id="translatedtitle">Surface Water and Ocean <span class="hlt">Topography</span> (SWOT) mission</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Neeck, Steven P.; Lindstrom, Eric J.; Vaze, Parag V.; Fu, Lee-Lueng</p> <p>2012-09-01</p> <p>The Surface Water Ocean <span class="hlt">Topography</span> (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 <span class="hlt">topography</span> 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/21775593','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21775593"><span id="translatedtitle">Electroencephalographic <span class="hlt">topography</span> measures of experienced utility.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Pedroni, Andreas; Langer, Nicolas; Koenig, Thomas; Allemand, Michael; Jäncke, Lutz</p> <p>2011-07-20</p> <p>Economic theory distinguishes two concepts of utility: decision utility, objectively quantifiable by choices, and experienced utility, referring to the satisfaction by an obtainment. To date, experienced utility is typically measured with subjective ratings. This study intended to quantify experienced utility by global levels of neuronal activity. Neuronal activity was measured by means of electroencephalographic (EEG) responses to gain and omission of graded monetary rewards at the level of the EEG <span class="hlt">topography</span> in human subjects. A novel analysis approach allowed approximating psychophysiological value functions for the experienced utility of monetary rewards. In addition, we identified the time windows of the event-related potentials (ERP) and the respective intracortical sources, in which variations in neuronal activity were significantly related to the value or valence of outcomes. Results indicate that value functions of experienced utility and regret disproportionally increase with monetary value, and thus contradict the compressing value functions of decision utility. The temporal pattern of outcome evaluation suggests an initial (∼250 ms) coarse evaluation regarding the valence, concurrent with a finer-grained evaluation of the value of gained rewards, whereas the evaluation of the value of omitted rewards emerges later. We hypothesize that this temporal double dissociation is explained by reward prediction errors. Finally, a late, yet unreported, reward-sensitive ERP <span class="hlt">topography</span> (∼500 ms) was identified. The sources of these topographical covariations are estimated in the ventromedial prefrontal cortex, the medial frontal gyrus, the anterior and posterior cingulate cortex and the hippocampus/amygdala. The results provide important new evidence regarding "how," "when," and "where" the brain evaluates outcomes with different hedonic impact. PMID:21775593</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1995SPIE.2393...10J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1995SPIE.2393...10J"><span id="translatedtitle">Evaluation of the PAR corneal <span class="hlt">topography</span> system</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jindal, Prateek; Cheung, Susan; Pirouzian, Amir; Keates, Richard H.; Ren, Qiushi</p> <p>1995-05-01</p> <p>The purpose of this study was to evaluate the raster photogrammetry based Corneal <span class="hlt">Topography</span> 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 <span class="hlt">Topography</span> 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22218280','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22218280"><span id="translatedtitle"><span class="hlt">Absolute</span> and relative dosimetry for ELIMED</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Cirrone, G. A. P.; Schillaci, F.; Scuderi, V.; Cuttone, G.; Candiano, G.; Musumarra, A.; Pisciotta, P.; Romano, F.; Carpinelli, M.; Presti, D. Lo; Raffaele, L.; Tramontana, A.; Cirio, R.; Sacchi, R.; Monaco, V.; Marchetto, F.; Giordanengo, S.</p> <p>2013-07-26</p> <p>The definition of detectors, methods and procedures for the <span class="hlt">absolute</span> and relative dosimetry of laser-driven proton beams is a crucial step toward the clinical use of this new kind of beams. Hence, one of the ELIMED task, will be the definition of procedures aiming to obtain an <span class="hlt">absolute</span> dose measure at the end of the transport beamline with an accuracy as close as possible to the one required for clinical applications (i.e. of the order of 5% or less). Relative dosimetry procedures must be established, as well: they are necessary in order to determine and verify the beam dose distributions and to monitor the beam fluence and the energetic spectra during irradiations. Radiochromic films, CR39, Faraday Cup, Secondary Emission Monitor (SEM) and transmission ionization chamber will be considered, designed and studied in order to perform a fully dosimetric characterization of the ELIMED proton beam.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25423049','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25423049"><span id="translatedtitle">Probing <span class="hlt">absolute</span> spin polarization at the nanoscale.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Eltschka, Matthias; Jäck, Berthold; Assig, Maximilian; Kondrashov, Oleg V; Skvortsov, Mikhail A; Etzkorn, Markus; Ast, Christian R; Kern, Klaus</p> <p>2014-12-10</p> <p>Probing <span class="hlt">absolute</span> values of spin polarization at the nanoscale offers insight into the fundamental mechanisms of spin-dependent transport. Employing the Zeeman splitting in superconducting tips (Meservey-Tedrow-Fulde effect), we introduce a novel spin-polarized scanning tunneling microscopy that combines the probing capability of the <span class="hlt">absolute</span> values of spin polarization with precise control at the atomic scale. We utilize our novel approach to measure the locally resolved spin polarization of magnetic Co nanoislands on Cu(111). We find that the spin polarization is enhanced by 65% when increasing the width of the tunnel barrier by only 2.3 Å due to the different decay of the electron orbitals into vacuum. PMID:25423049</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22340250','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22340250"><span id="translatedtitle"><span class="hlt">Absolute</span>-magnitude distributions of supernovae</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Richardson, Dean; Wright, John; Jenkins III, Robert L.; Maddox, Larry</p> <p>2014-05-01</p> <p>The <span class="hlt">absolute</span>-magnitude distributions of seven supernova (SN) types are presented. The data used here were primarily taken from the Asiago Supernova Catalogue, but were supplemented with additional data. We accounted for both foreground and host-galaxy extinction. A bootstrap method is used to correct the samples for Malmquist bias. Separately, we generate volume-limited samples, restricted to events within 100 Mpc. We find that the superluminous events (M{sub B} < –21) make up only about 0.1% of all SNe in the bias-corrected sample. The subluminous events (M{sub B} > –15) make up about 3%. The normal Ia distribution was the brightest with a mean <span class="hlt">absolute</span> blue magnitude of –19.25. The IIP distribution was the dimmest at –16.75.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19750063653&hterms=VALUE+ABSOLUTE&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DVALUE%2BABSOLUTE','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19750063653&hterms=VALUE+ABSOLUTE&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DVALUE%2BABSOLUTE"><span id="translatedtitle"><span class="hlt">Absolute</span> radiometry and the solar constant</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Willson, R. C.</p> <p>1974-01-01</p> <p>A series of active cavity radiometers (ACRs) are described which have been developed as standard detectors for the accurate measurement of irradiance in <span class="hlt">absolute</span> units. It is noted that the ACR is an electrical substitution calorimeter, is designed for automatic remote operation in any environment, and can make irradiance measurements in the range from low-level IR fluxes up to 30 solar constants with small <span class="hlt">absolute</span> uncertainty. The instrument operates in a differential mode by chopping the radiant flux to be measured at a slow rate, and irradiance is determined from two electrical power measurements together with the instrumental constant. Results are reported for measurements of the solar constant with two types of ACRs. The more accurate measurement yielded a value of 136.6 plus or minus 0.7 mW/sq cm (1.958 plus or minus 0.010 cal/sq cm per min).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19920003670','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19920003670"><span id="translatedtitle">Asteroid <span class="hlt">absolute</span> magnitudes and slope parameters</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Tedesco, Edward F.</p> <p>1991-01-01</p> <p>A new listing of <span class="hlt">absolute</span> magnitudes (H) and slope parameters (G) has been created and published in the Minor Planet Circulars; this same listing will appear in the 1992 Ephemerides of Minor Planets. Unlike previous listings, the values of the current list were derived from fits of data at the V band. All observations were reduced in the same fashion using, where appropriate, a single basis default value of 0.15 for the slope parameter. Distances and phase angles were computed for each observation. The data for 113 asteroids was of sufficiently high quality to permit derivation of their H and G. These improved <span class="hlt">absolute</span> magnitudes and slope parameters will be used to deduce the most reliable bias-corrected asteroid size-frequency distribution yet made.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/73021','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/73021"><span id="translatedtitle"><span class="hlt">Absolute</span> calibration of TFTR helium proportional counters</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Strachan, J.D.; Diesso, M.; Jassby, D.; Johnson, L.; McCauley, S.; Munsat, T.; Roquemore, A.L.; Barnes, C.W. |; Loughlin, M. |</p> <p>1995-06-01</p> <p>The TFTR helium proportional counters are located in the central five (5) channels of the TFTR multichannel neutron collimator. These detectors were <span class="hlt">absolutely</span> calibrated using a 14 MeV neutron generator positioned at the horizontal midplane of the TFTR vacuum vessel. The neutron generator position was scanned in centimeter steps to determine the collimator aperture width to 14 MeV neutrons and the <span class="hlt">absolute</span> sensitivity of each channel. Neutron profiles were measured for TFTR plasmas with time resolution between 5 msec and 50 msec depending upon count rates. The He detectors were used to measure the burnup of 1 MeV tritons in deuterium plasmas, the transport of tritium in trace tritium experiments, and the residual tritium levels in plasmas following 50:50 DT experiments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/16342798','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/16342798"><span id="translatedtitle"><span class="hlt">Absolute</span> enantioselective separation: optical activity ex machina.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bielski, Roman; Tencer, Michal</p> <p>2005-11-01</p> <p>The paper describes methodology of using three independent macroscopic factors affecting molecular orientation to accomplish separation of a racemic mixture without the presence of any other chiral compounds, i. e., <span class="hlt">absolute</span> enantioselective separation (AES) which is an extension of a concept of applying these factors to <span class="hlt">absolute</span> asymmetric synthesis. The three factors may be applied simultaneously or, if their effects can be retained, consecutively. The resulting three mutually orthogonal or near orthogonal directors constitute a true chiral influence and their scalar triple product is the measure of the chirality of the system. AES can be executed in a chromatography-like microfluidic process in the presence of an electric field. It may be carried out on a chemically modified flat surface, a monolithic polymer column made of a mesoporous material, each having imparted directional properties. Separation parameters were estimated for these media and possible implications for the natural homochirality are discussed. PMID:16342798</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PhyA..407...15O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PhyA..407...15O"><span id="translatedtitle">An <span class="hlt">absolute</span> measure for a key currency</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Oya, Shunsuke; Aihara, Kazuyuki; Hirata, Yoshito</p> <p></p> <p>It is generally considered that the US dollar and the euro are the key currencies in the world and in Europe, respectively. However, there is no <span class="hlt">absolute</span> general measure for a key currency. Here, we investigate the 24-hour periodicity of foreign exchange markets using a recurrence plot, and define an <span class="hlt">absolute</span> measure for a key currency based on the strength of the periodicity. Moreover, we analyze the time evolution of this measure. The results show that the credibility of the US dollar has not decreased significantly since the Lehman shock, when the Lehman Brothers bankrupted and influenced the economic markets, and has increased even relatively better than that of the euro and that of the Japanese yen.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120011123','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120011123"><span id="translatedtitle">From Hubble's NGSL to <span class="hlt">Absolute</span> Fluxes</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Heap, Sara R.; Lindler, Don</p> <p>2012-01-01</p> <p>Hubble's Next Generation Spectral Library (NGSL) consists of R-l000 spectra of 374 stars of assorted temperature, gravity, and metallicity. Each spectrum covers the wavelength range, 0.18-1.00 microns. The library can be viewed and/or downloaded from the website, http://archive.stsci.edu/prepds/stisngsll. Stars in the NGSL are now being used as <span class="hlt">absolute</span> flux standards at ground-based observatories. However, the uncertainty in the <span class="hlt">absolute</span> flux is about 2%, which does not meet the requirements of dark-energy surveys. We are therefore developing an observing procedure that should yield fluxes with uncertainties less than 1 % and will take part in an HST proposal to observe up to 15 stars using this new procedure.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008JLTP..151.1055L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008JLTP..151.1055L"><span id="translatedtitle">Metallic Magnetic Calorimeters for <span class="hlt">Absolute</span> Activity Measurement</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Loidl, M.; Leblanc, E.; Rodrigues, M.; Bouchard, J.; Censier, B.; Branger, T.; Lacour, D.</p> <p>2008-05-01</p> <p>We present a prototype of metallic magnetic calorimeters that we are developing for <span class="hlt">absolute</span> activity measurements of low energy emitting radionuclides. We give a detailed description of the realization of the prototype, containing an 55Fe source inside the detector absorber. We present the analysis of first data taken with this detector and compare the result of activity measurement with liquid scintillation counting. We also propose some ways for reducing the uncertainty on the activity determination with this new technique.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19850050574&hterms=VALUE+ABSOLUTE&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DVALUE%2BABSOLUTE','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19850050574&hterms=VALUE+ABSOLUTE&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DVALUE%2BABSOLUTE"><span id="translatedtitle"><span class="hlt">Absolute</span> photoionization cross sections of atomic oxygen</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Samson, J. A. R.; Pareek, P. N.</p> <p>1985-01-01</p> <p>The <span class="hlt">absolute</span> values of photoionization cross sections of atomic oxygen were measured from the ionization threshold to 120 A. An auto-ionizing resonance belonging to the 2S2P4(4P)3P(3Do, 3So) transition was observed at 479.43 A and another line at 389.97 A. The experimental data is in excellent agreement with rigorous close-coupling calculations that include electron correlations in both the initial and final states.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19840024060','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19840024060"><span id="translatedtitle"><span class="hlt">Absolute</span> photoionization cross sections of atomic oxygen</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Samson, J. A. R.; Pareek, P. N.</p> <p>1982-01-01</p> <p>The <span class="hlt">absolute</span> values of photoionization cross sections of atomic oxygen were measured from the ionization threshold to 120 A. An auto-ionizing resonance belonging to the 2S2P4(4P)3P(3Do, 3So) transition was observed at 479.43 A and another line at 389.97 A. The experimental data is in excellent agreement with rigorous close-coupling calculations that include electron correlations in both the initial and final states.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21410350','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21410350"><span id="translatedtitle">Silicon <span class="hlt">Absolute</span> X-Ray Detectors</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Seely, John F.; Korde, Raj; Sprunck, Jacob; Medjoubi, Kadda; Hustache, Stephanie</p> <p>2010-06-23</p> <p>The responsivity of silicon photodiodes having no loss in the entrance window, measured using synchrotron radiation in the 1.75 to 60 keV range, was compared to the responsivity calculated using the silicon thickness measured using near-infrared light. The measured and calculated responsivities agree with an average difference of 1.3%. This enables their use as <span class="hlt">absolute</span> x-ray detectors.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26056340','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26056340"><span id="translatedtitle">Blood pressure targets and <span class="hlt">absolute</span> cardiovascular risk.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Odutayo, Ayodele; Rahimi, Kazem; Hsiao, Allan J; Emdin, Connor A</p> <p>2015-08-01</p> <p>In the Eighth Joint National Committee guideline on hypertension, the threshold for the initiation of blood pressure-lowering treatment for elderly adults (≥60 years) without chronic kidney disease or diabetes mellitus was raised from 140/90 mm Hg to 150/90 mm Hg. However, the committee was not unanimous in this decision, particularly because a large proportion of adults ≥60 years may be at high cardiovascular risk. On the basis of Eighth Joint National Committee guideline, we sought to determine the <span class="hlt">absolute</span> 10-year risk of cardiovascular disease among these adults through analyzing the National Health and Nutrition Examination Survey (2005-2012). The primary outcome measure was the proportion of adults who were at ≥20% predicted <span class="hlt">absolute</span> cardiovascular risk and above goals for the Seventh Joint National Committee guideline but reclassified as at target under the Eighth Joint National Committee guideline (reclassified). The Framingham General Cardiovascular Disease Risk Score was used. From 2005 to 2012, the surveys included 12 963 adults aged 30 to 74 years with blood pressure measurements, of which 914 were reclassified based on the guideline. Among individuals reclassified as not in need of additional treatment, the proportion of adults 60 to 74 years without chronic kidney disease or diabetes mellitus at ≥20% <span class="hlt">absolute</span> risk was 44.8%. This corresponds to 0.8 million adults. The proportion at high cardiovascular risk remained sizable among adults who were not receiving blood pressure-lowering treatment. Taken together, a sizable proportion of reclassified adults 60 to 74 years without chronic kidney disease or diabetes mellitus was at ≥20% <span class="hlt">absolute</span> cardiovascular risk. PMID:26056340</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26280315','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26280315"><span id="translatedtitle">Relative errors can cue <span class="hlt">absolute</span> visuomotor mappings.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>van Dam, Loes C J; Ernst, Marc O</p> <p>2015-12-01</p> <p>When repeatedly switching between two visuomotor mappings, e.g. in a reaching or pointing task, adaptation tends to speed up over time. That is, when the error in the feedback corresponds to a mapping switch, fast adaptation occurs. Yet, what is learned, the relative error or the <span class="hlt">absolute</span> mappings? When switching between mappings, errors with a size corresponding to the relative difference between the mappings will occur more often than other large errors. Thus, we could learn to correct more for errors with this familiar size (Error Learning). On the other hand, it has been shown that the human visuomotor system can store several <span class="hlt">absolute</span> visuomotor mappings (Mapping Learning) and can use associated contextual cues to retrieve them. Thus, when contextual information is present, no error feedback is needed to switch between mappings. Using a rapid pointing task, we investigated how these two types of learning may each contribute when repeatedly switching between mappings in the absence of task-irrelevant contextual cues. After training, we examined how participants changed their behaviour when a single error probe indicated either the often-experienced error (Error Learning) or one of the previously experienced <span class="hlt">absolute</span> mappings (Mapping Learning). Results were consistent with Mapping Learning despite the relative nature of the error information in the feedback. This shows that errors in the feedback can have a double role in visuomotor behaviour: they drive the general adaptation process by making corrections possible on subsequent movements, as well as serve as contextual cues that can signal a learned <span class="hlt">absolute</span> mapping. PMID:26280315</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1981ApOpt..20..400B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1981ApOpt..20..400B"><span id="translatedtitle"><span class="hlt">Absolute</span> distance measurements by variable wavelength interferometry</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bien, F.; Camac, M.; Caulfield, H. J.; Ezekiel, S.</p> <p>1981-02-01</p> <p>This paper describes a laser interferometer which provides <span class="hlt">absolute</span> distance measurements using tunable lasers. An active feedback loop system, in which the laser frequency is locked to the optical path length difference of the interferometer, is used to tune the laser wavelengths. If the two wavelengths are very close, electronic frequency counters can be used to measure the beat frequency between the two laser frequencies and thus to determine the optical path difference between the two legs of the interferometer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014RMxAC..44Q.191C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014RMxAC..44Q.191C"><span id="translatedtitle">Morphology and <span class="hlt">Absolute</span> Magnitudes of the SDSS DR7 QSOs</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Coelho, B.; Andrei, A. H.; Antón, S.</p> <p>2014-10-01</p> <p>The ESA mission Gaia will furnish a complete census of the Milky Way, delivering astrometrics, <span class="hlt">dynamics</span>, and astrophysics information for 1 billion stars. Operating in all-sky repeated survey mode, Gaia will also provide measurements of extra-galactic objects. Among the later there will be at least 500,000 QSOs that will be used to build the reference frame upon which the several independent observations will be combined and interpreted. Not all the QSOs are equally suited to fulfill this role of fundamental, fiducial grid-points. Brightness, morphology, and variability define the astrometric error budget for each object. We made use of 3 morphological parameters based on the PSF sharpness, circularity and gaussianity, which enable us to distinguish the "real point-like" QSOs. These parameters are being explored on the spectroscopically certified QSOs of the SDSS DR7, to compare the performance against other morphology classification schemes, as well as to derive properties of the host galaxy. We present a new method, based on the Gaia quasar database, to derive <span class="hlt">absolute</span> magnitudes, on the SDSS filters domain. The method can be extrapolated all over the optical window, including the Gaia filters. We discuss colors derived from SDSS apparent magnitudes and colors based on <span class="hlt">absolute</span> magnitudes that we obtained tanking into account corrections for dust extinction, either intergalactic or from the QSO host, and for the Lyman α forest. In the future we want to further discuss properties of the host galaxies, comparing for e.g. the obtained morphological classification with the color, the apparent and <span class="hlt">absolute</span> magnitudes, and the redshift distributions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/16177516','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/16177516"><span id="translatedtitle"><span class="hlt">Absolute</span> dose calculations for Monte Carlo simulations of radiotherapy beams.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Popescu, I A; Shaw, C P; Zavgorodni, S F; Beckham, W A</p> <p>2005-07-21</p> <p>Monte Carlo (MC) simulations have traditionally been used for single field relative comparisons with experimental data or commercial treatment planning systems (TPS). However, clinical treatment plans commonly involve more than one field. Since the contribution of each field must be accurately quantified, multiple field MC simulations are only possible by employing <span class="hlt">absolute</span> dosimetry. Therefore, we have developed a rigorous calibration method that allows the incorporation of monitor units (MU) in MC simulations. This <span class="hlt">absolute</span> dosimetry formalism can be easily implemented by any BEAMnrc/DOSXYZnrc user, and applies to any configuration of open and blocked fields, including intensity-modulated radiation therapy (IMRT) plans. Our approach involves the relationship between the dose scored in the monitor ionization chamber of a radiotherapy linear accelerator (linac), the number of initial particles incident on the target, and the field size. We found that for a 10 x 10 cm2 field of a 6 MV photon beam, 1 MU corresponds, in our model, to 8.129 x 10(13) +/- 1.0% electrons incident on the target and a total dose of 20.87 cGy +/- 1.0% in the monitor chambers of the virtual linac. We present an extensive experimental verification of our MC results for open and intensity-modulated fields, including a <span class="hlt">dynamic</span> 7-field IMRT plan simulated on the CT data sets of a cylindrical phantom and of a Rando anthropomorphic phantom, which were validated by measurements using ionization chambers and thermoluminescent dosimeters (TLD). Our simulation results are in excellent agreement with experiment, with percentage differences of less than 2%, in general, demonstrating the accuracy of our Monte Carlo <span class="hlt">absolute</span> dose calculations. PMID:16177516</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005PMB....50.3375P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005PMB....50.3375P"><span id="translatedtitle"><span class="hlt">Absolute</span> dose calculations for Monte Carlo simulations of radiotherapy beams</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Popescu, I. A.; Shaw, C. P.; Zavgorodni, S. F.; Beckham, W. A.</p> <p>2005-07-01</p> <p>Monte Carlo (MC) simulations have traditionally been used for single field relative comparisons with experimental data or commercial treatment planning systems (TPS). However, clinical treatment plans commonly involve more than one field. Since the contribution of each field must be accurately quantified, multiple field MC simulations are only possible by employing <span class="hlt">absolute</span> dosimetry. Therefore, we have developed a rigorous calibration method that allows the incorporation of monitor units (MU) in MC simulations. This <span class="hlt">absolute</span> dosimetry formalism can be easily implemented by any BEAMnrc/DOSXYZnrc user, and applies to any configuration of open and blocked fields, including intensity-modulated radiation therapy (IMRT) plans. Our approach involves the relationship between the dose scored in the monitor ionization chamber of a radiotherapy linear accelerator (linac), the number of initial particles incident on the target, and the field size. We found that for a 10 × 10 cm2 field of a 6 MV photon beam, 1 MU corresponds, in our model, to 8.129 × 1013 ± 1.0% electrons incident on the target and a total dose of 20.87 cGy ± 1.0% in the monitor chambers of the virtual linac. We present an extensive experimental verification of our MC results for open and intensity-modulated fields, including a <span class="hlt">dynamic</span> 7-field IMRT plan simulated on the CT data sets of a cylindrical phantom and of a Rando anthropomorphic phantom, which were validated by measurements using ionization chambers and thermoluminescent dosimeters (TLD). Our simulation results are in excellent agreement with experiment, with percentage differences of less than 2%, in general, demonstrating the accuracy of our Monte Carlo <span class="hlt">absolute</span> dose calculations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2000SPIE.3998..838B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2000SPIE.3998..838B"><span id="translatedtitle"><span class="hlt">Absolute</span> dosimetry for extreme-ultraviolet lithography</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Berger, Kurt W.; Campiotti, Richard H.</p> <p>2000-06-01</p> <p>The accurate measurement of an exposure dose reaching the wafer on an extreme ultraviolet (EUV) lithographic system has been a technical challenge directly applicable to the evaluation of candidate EUV resist materials and calculating lithography system throughputs. We have developed a dose monitoring sensor system that can directly measure EUV intensities at the wafer plane of a prototype EUV lithographic system. This sensor system, located on the wafer stage adjacent to the electrostatic chuck used to grip wafers, operates by translating the sensor into the aerial image, typically illuminating an 'open' (unpatterned) area on the reticle. The <span class="hlt">absolute</span> signal strength can be related to energy density at the wafer, and thus used to determine resist sensitivity, and the signal as a function of position can be used to determine illumination uniformity at the wafer plane. Spectral filtering to enhance the detection of 13.4 nm radiation was incorporated into the sensor. Other critical design parameters include the packaging and amplification technologies required to place this device into the space and vacuum constraints of a EUV lithography environment. We describe two approaches used to determine the <span class="hlt">absolute</span> calibration of this sensor. The first conventional approach requires separate characterization of each element of the sensor. A second novel approach uses x-ray emission from a mildly radioactive iron source to calibrate the <span class="hlt">absolute</span> response of the entire sensor system (detector and electronics) in a single measurement.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27151628','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27151628"><span id="translatedtitle">Graphene <span class="hlt">Topographies</span>: Multiscale Graphene <span class="hlt">Topographies</span> Programmed by Sequential Mechanical Deformation (Adv. Mater. 18/2016).</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chen, Po-Yen; Sodhi, Jaskiranjeet; Qiu, Yang; Valentin, Thomas M; Steinberg, Ruben Spitz; Wang, Zhongying; Hurt, Robert H; Wong, Ian Y</p> <p>2016-05-01</p> <p>P.-Y. Chen, R. H. Hurt, I. Y. Wong and co-workers demonstrate a hierarchical graphene surface architecture generated by using various sequences and combinations of extreme mechanical deformation, as shown in the false-colored SEM image. As described on page 3564, the sequential patterning approach enables the design of feature sizes and orientations across multiple length scales which are retained during mechanical deformations of similar extent. This results in sequence-dependent surface <span class="hlt">topographies</span> with structural memory. PMID:27151628</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ApGeo..13..209C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ApGeo..13..209C"><span id="translatedtitle">Distribution of ice thickness and subglacial <span class="hlt">topography</span> of the "Chinese Wall" around Kunlun Station, East Antarctica</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cui, Xiang-Bin; Sun, Bo; Su, Xiao-Gang; Guo, Jing-Xue</p> <p>2016-03-01</p> <p>As fundamental parameters of the Antarctic Ice Sheet, ice thickness and subglacial <span class="hlt">topography</span> are critical factors for studying the basal conditions and mass balance in Antarctica. During CHINARE 24 (the 24th Chinese National Antarctic Research Expedition, 2007/08), the research team used a deep ice-penetrating radar system to measure the ice thickness and subglacial <span class="hlt">topography</span> of the "Chinese Wall" around Kunlun Station, East Antarctica. Preliminary results show that the ice thickness varies mostly from 1600 m to 2800 m along the "Chinese Wall", with the thickest ice being 3444 m, and the thinnest ice 1255 m. The average bedrock elevation is 1722 m, while the minimum is just 604 m. Compared with the northern side of the ice divide, the ice thickness is a little greater and the subglacial <span class="hlt">topography</span> lower on the southern side, which is also characterized by four deep valleys. We found no basal freeze-on ice in the Gamburtsev Subglacial Mountains area, subglacial lakes, or water bodies along the "Chinese Wall". Ice thickness and subglacial <span class="hlt">topography</span> data extracted from the Bedmap 2 database along the "Chinese Wall" are consistent with our results, but their resolution and accuracy are very limited in areas where the bedrock fluctuates intensely. The distribution of ice thickness and subglacial <span class="hlt">topography</span> detected by ice-penetrating radar clarifies the features of the ice sheet in this "inaccessible" region. These results will help to advance the study of ice sheet <span class="hlt">dynamics</span> and the determination of future locations of the GSM's geological and deep ice core drilling sites in the Dome A region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/433054','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/433054"><span id="translatedtitle">Representation of <span class="hlt">topography</span> in spectral climate models and its effect on simulated precipitation</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lindberg, C.; Broccoli, A.J.</p> <p>1996-11-01</p> <p>Spectral climate models are distinguished by their representation of variables as finite sums of spherical harmonics, with coefficients computed by an orthogonal projection of the variables onto the spherical harmonics. Representing the surface elevation in this manner results in its contamination by Gibbs-like truncation artifacts, which appear as spurious valleys and mountain chains in the <span class="hlt">topography</span>. These {open_quotes}Gibbs ripples{close_quotes} are present in the surface <span class="hlt">topographies</span> of spectral climate models from a number of research institutions. Integrations of the Geophysical Fluid <span class="hlt">Dynamics</span> Laboratory (GFDL) climate model over a range of horizontal resolutions indicate that the Gibbs ripples lead to spurious, small-scale extrema in the spatial distribution of precipitation. This {open_quotes}cellular precipitation pathology{close_quotes} becomes more pronounced with increasing horizontal resolution, causing a deterioration in the fidelity of simulated precipitation in higher resolution models. A method is described for reducing the Gibbs ripples that occur when making an incomplete spherical harmonic expansion of the <span class="hlt">topography</span>. The new spherical harmonic representations of <span class="hlt">topography</span> are formed by fitting a nonuniform spherical smoothing spline to geodetic data and found by solving a fixed-point problem. This regularization technique results in less distortion of features such as mountain height and continental boundaries than previous smoothing methods. These new expansions of the <span class="hlt">topography</span>, when used as a lower boundary surface in the GFDL climate model, substantially diminish the cellular precipitation pathology and produce markedly more realistic simulations of precipitation. These developments make the prospect of using higher resolution spectral models for studies of regional hydrologic climate more attractive. 34 refs., 11 figs., 1 tab.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19910006329','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19910006329"><span id="translatedtitle">Mantle <span class="hlt">dynamics</span> and geodesy</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Albee, Arden</p> <p>1990-01-01</p> <p>Both completed work and work that is still in progress are presented. The completed work presented includes: (1) core-mantle boundary <span class="hlt">topography</span>; (2) <span class="hlt">absolute</span> value for mantle viscosity; (3) code development; (4) lateral heterogeneity of subduction zone rheology; and (5) planning for the Coolfront meeting. The work presented that is still in progress includes: (1) geoid anomalies for a chemically stratified mantle; and (2) geoid anomalies with lateral variations in viscosity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AGUFM.V31A0952R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AGUFM.V31A0952R"><span id="translatedtitle">Simulation of 3D Seismic Wave Propagation with Volcano <span class="hlt">Topography</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ripperger, J.; Igel, H.; Wassermann, J.</p> <p>2001-12-01</p> <p>We investigate the possibilities of using three-dimensional finite difference (FD) methods for numerical simulation of the seismic wave field at active volcanoes. We put special emphasis on the implementation of the boundary conditions for free surface <span class="hlt">topography</span>. We compare two different approaches to solve the free surface boundary conditions. The algorithms are implemented on parallel hardware and have been tested for correctness and stability. We apply them to smooth artificial <span class="hlt">topographies</span> and to the real <span class="hlt">topography</span> of Mount Merapi, Indonesia. We conclude, that grid stretching type methods (e.g. Hestholm & Ruud, 1994) are not well suited for realistic volcano <span class="hlt">topography</span> as they tend to become unstable for large topographic gradients. The representation of <span class="hlt">topography</span> through staircase shaped grids (Ohminato & Chouet, 1997) results in stable calculations, while demanding very fine gridding. The simulations show the effects of a three-dimensional surface <span class="hlt">topography</span> on elastic wave propagation. Ground motion at the surface is severely affected by <span class="hlt">topography</span>. If neglected, this may jeopardize attempts to determine source location by analyzing particle motion. Numerical studies like this can help to understand wave propagation phenomena observed on field recordings in volcano seismology. Future studies will aim at separating the wave effects of internal scattering, <span class="hlt">topography</span> and sources (tremors, tectonic events, pyroclastic flows).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4191383','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4191383"><span id="translatedtitle"><span class="hlt">Absolute</span> and relative quantification of RNA modifications via biosynthetic isotopomers</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Kellner, Stefanie; Ochel, Antonia; Thüring, Kathrin; Spenkuch, Felix; Neumann, Jennifer; Sharma, Sunny; Entian, Karl-Dieter; Schneider, Dirk; Helm, Mark</p> <p>2014-01-01</p> <p>In the resurging field of RNA modifications, quantification is a bottleneck blocking many exciting avenues. With currently over 150 known nucleoside alterations, detection and quantification methods must encompass multiple modifications for a comprehensive profile. LC–MS/MS approaches offer a perspective for comprehensive parallel quantification of all the various modifications found in total RNA of a given organism. By feeding 13C-glucose as sole carbon source, we have generated a stable isotope-labeled internal standard (SIL-IS) for bacterial RNA, which facilitates relative comparison of all modifications. While conventional SIL-IS approaches require the chemical synthesis of single modifications in weighable quantities, this SIL-IS consists of a nucleoside mixture covering all detectable RNA modifications of Escherichia coli, yet in small and initially unknown quantities. For <span class="hlt">absolute</span> in addition to relative quantification, those quantities were determined by a combination of external calibration and sample spiking of the biosynthetic SIL-IS. For each nucleoside, we thus obtained a very robust relative response factor, which permits direct conversion of the MS signal to <span class="hlt">absolute</span> amounts of substance. The application of the validated SIL-IS allowed highly precise quantification with standard deviations <2% during a 12-week period, and a linear <span class="hlt">dynamic</span> range that was extended by two orders of magnitude. PMID:25129236</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/18019234','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/18019234"><span id="translatedtitle">Simulation of <span class="hlt">absolute</span> amplitudes of ultrasound signals using equivalent circuits.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Johansson, Jonny; Martinsson, Pär-Erik; Delsing, Jerker</p> <p>2007-10-01</p> <p>Equivalent circuits for piezoelectric devices and ultrasonic transmission media can be used to cosimulate electronics and ultrasound parts in simulators originally intended for electronics. To achieve efficient system-level optimization, it is important to simulate correct, <span class="hlt">absolute</span> amplitude of the ultrasound signal in the system, as this determines the requirements on the electronics regarding <span class="hlt">dynamic</span> range, circuit noise, and power consumption. This paper presents methods to achieve correct, <span class="hlt">absolute</span> amplitude of an ultrasound signal in a simulation of a pulse-echo system using equivalent circuits. This is achieved by taking into consideration loss due to diffraction and the effect of the cable that connects the electronics and the piezoelectric transducer. The conductive loss in the transmission line that models the propagation media of the ultrasound pulse is used to model the loss due to diffraction. Results show that the simulated amplitude of the echo follows measured values well in both near and far fields, with an offset of about 10%. The use of a coaxial cable introduces inductance and capacitance that affect the amplitude of a received echo. Amplitude variations of 60% were observed when the cable length was varied between 0.07 m and 2.3 m, with simulations predicting similar variations. The high precision in the achieved results show that electronic design and system optimization can rely on system simulations alone. This will simplify the development of integrated electronics aimed at ultrasound systems. PMID:18019234</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JMP....53i5205A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JMP....53i5205A"><span id="translatedtitle"><span class="hlt">Absolutely</span> continuous spectrum implies ballistic transport for quantum particles in a random potential on tree graphs</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Aizenman, Michael; Warzel, Simone</p> <p>2012-09-01</p> <p>We discuss the <span class="hlt">dynamical</span> implications of the recent proof that for a quantum particle in a random potential on a regular tree graph <span class="hlt">absolutely</span> continuous (ac) spectrum occurs non-perturbatively through rare fluctuation-enabled resonances. The main result is spelled in the title.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22093718','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22093718"><span id="translatedtitle"><span class="hlt">Absolutely</span> continuous spectrum implies ballistic transport for quantum particles in a random potential on tree graphs</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Aizenman, Michael; Warzel, Simone</p> <p>2012-09-15</p> <p>We discuss the <span class="hlt">dynamical</span> implications of the recent proof that for a quantum particle in a random potential on a regular tree graph <span class="hlt">absolutely</span> continuous (ac) spectrum occurs non-perturbatively through rare fluctuation-enabled resonances. The main result is spelled in the title.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=PIA02765&hterms=depression+resistant&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Ddepression%2Bresistant','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=PIA02765&hterms=depression+resistant&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Ddepression%2Bresistant"><span id="translatedtitle">Stereo Pair: Inverted <span class="hlt">Topography</span>, Patagonia, Argentina</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2000-01-01</p> <p><p/> The Meseta de Somuncura is a broad plateau capped by basalt. Near its western edge is evidence of multiple volcanic events and a complex erosion history. Most notable are the long, narrow-, and winding lava flows that run across most of the right side of the image. These formed from low-viscosity lava that flowed down gullies over fairly flat terrain. Later, erosion of the landscape continued and the solidified flows were more resistant than the older surrounding rocks. Consequently, the flows became the ridges we see here. This natural process of converting gullies to ridges is called topographic inversion. See image PIA02755 (upper left corner) for a good example of topographic inversion in its earlier stages.<p/>Other features seen here include numerous and varied closed depressions. The regional drainage is not well integrated, and drainage ends up in salty lakes (blue if shallow, black if deep). Wind streaks indicate that winds blow toward the east (right) and blow salt grains off the lakebeds when dry. The bowtie pattern in the upper left has resulted from differing grazing practices among fenced fields.<p/>This cross-eyed stereoscopic image pair was generated using topographic data from the Shuttle Radar <span class="hlt">Topography</span> Mission, combined with an enhanced Landsat 7satellite color image. The <span class="hlt">topography</span> data are used to create two differing perspectives of a single image, one perspective for each eye. In doing so, each point in the image is shifted slightly, depending on its elevation. When stereoscopically merged, the result is a vertically exaggerated view of the Earth's surface in its full three dimensions.<p/>Landsat satellites have provided visible light and infrared images of the Earth continuously since 1972. SRTM topographic data match the 30-meter (99-foot) spatial resolution of most Landsat images and provide a valuable complement for studying the historic and growing Landsat data archive. The Landsat 7 Thematic Mapper image used here was provided to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=PIA00738&hterms=Horses&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DHorses','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=PIA00738&hterms=Horses&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DHorses"><span id="translatedtitle"><span class="hlt">Topography</span> and Volcanoes on Io (color)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1997-01-01</p> <p>The images used to create this enhanced color composite of Io were acquired by NASA's Galileo spacecraft during its seventh orbit (G7) of Jupiter. Low sun angles near the terminator (day-night boundary near the left side of the image) offer lighting conditions which emphasize the <span class="hlt">topography</span> or relief on the volcanic satellite. The <span class="hlt">topography</span> appears very flat near the active volcanic centers such as Loki Patera (the large dark horse-shoe shaped feature near the terminator) while a variety of mountains and plateaus exist elsewhere. The big reddish-orange ring in the lower right is formed by material deposited from the eruption of Pele, Io's largest volcanic plume.<p/>North is to the top of this picture which merges images obtained with the clear, red, green, and violet filters of the solid state imaging (CCD) system on NASA's Galileo spacecraft. The resolution is 6.1 kilometers per picture element. The images were taken on April 4th, 1997 at a range of 600,000 kilometers.<p/>The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).<p/>Concurrent results from Galileo's exploration of Io appear in the October 15th, 1997 issue of Geophysical Research Letters. The papers are: Temperature and Area Constraints of the South Volund Volcano on Io from the NIMS and SSI Instruments during the Galileo G1 Orbit, by A.G. Davies, A.S. McEwen, R. Lopes-Gautier, L. Keszthelyi, R.W. Carlson and W.D. Smythe. High-temperature hot spots on Io as seen by the Galileo Solid-State Imaging (SSI) experiment, by A. McEwen, D. Simonelli, D. Senske, K. Klassen, L. Keszthelyi, T. Johnson, P. Geissler, M. Carr, and M. Belton. Io: Galileo evidence for major variations in regolith properties, by D. Simonelli, J. Veverka, and A. McEwen.<p/>This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3043653','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3043653"><span id="translatedtitle">Investigation of anal motor characteristics of the sensorimotor response (SMR) using 3-D anorectal pressure <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Cheeney, Gregory; Remes-Troche, Jose M.; Attaluri, Ashok</p> <p>2011-01-01</p> <p>Desire to defecate is associated with a unique anal contractile response, the sensorimotor response (SMR). However, the precise muscle(s) involved is not known. We aimed to examine the role of external and internal anal sphincter and the puborectalis muscle in the genesis of SMR. Anorectal 3-D pressure <span class="hlt">topography</span> was performed in 10 healthy subjects during graded rectal balloon distention using a novel high-definition manometry system consisting of a probe with 256 pressure sensors arranged circumferentially. The anal pressure changes before, during, and after the onset of SMR were measured at every millimeter along the length of anal canal and in 3-D by dividing the anal canal into 4 × 2.1-mm grids. Pressures were assessed in the longitudinal and anterior-posterior axis. Anal ultrasound was performed to assess puborectalis morphology. 3-D <span class="hlt">topography</span> demonstrated that rectal distention produced an SMR coinciding with desire to defecate and predominantly induced by contraction of puborectalis. Anal ultrasound showed that the puborectalis was located at mean distance of 3.5 cm from anal verge, which corresponded with peak pressure difference between the anterior and posterior vectors observed at 3.4 cm with 3-D <span class="hlt">topography</span> (r = 0.77). The highest <span class="hlt">absolute</span> and percentage increases in pressure during SMR were seen in the superior-posterior portion of anal canal, reaffirming the role of puborectalis. The SMR anal pressure profile showed a peak pressure at 1.6 cm from anal verge in the anterior and posterior vectors and distinct increase in pressure only posteriorly at 3.2 cm corresponding to puborectalis. We concluded that SMR is primarily induced by the activation and contraction of the puborectalis muscle in response to a sensation of a desire to defecate. PMID:21109594</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27085798','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27085798"><span id="translatedtitle">Tonal frequency affects amplitude but not <span class="hlt">topography</span> of rhesus monkey cranial EEG components.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Teichert, Tobias</p> <p>2016-06-01</p> <p>The rhesus monkey is an important model of human auditory function in general and auditory deficits in neuro-psychiatric diseases such as schizophrenia in particular. Several rhesus monkey studies have described homologs of clinically relevant auditory evoked potentials such as pitch-based mismatch negativity, a fronto-central negativity that can be observed when a series of regularly repeating sounds is disrupted by a sound of different tonal frequency. As a result it is well known how differences of tonal frequency are represented in rhesus monkey EEG. However, to date there is no study that systematically quantified how <span class="hlt">absolute</span> tonal frequency itself is represented. In particular, it is not known if frequency affects rhesus monkey EEG component amplitude and <span class="hlt">topography</span> in the same way as previously shown for humans. A better understanding of the effect of frequency may strengthen inter-species homology and will provide a more solid foundation on which to build the interpretation of frequency MMN in the rhesus monkey. Using arrays of up to 32 cranial EEG electrodes in 4 rhesus macaques we identified 8 distinct auditory evoked components including the N85, a fronto-central negativity that is the presumed homolog of the human N1. In line with human data, the amplitudes of most components including the N85 peaked around 1000 Hz and were strongly attenuated above ∼1750 Hz. Component <span class="hlt">topography</span>, however, remained largely unaffected by frequency. This latter finding may be consistent with the known absence of certain anatomical structures in the rhesus monkey that are believed to cause the changes in <span class="hlt">topography</span> in the human by inducing a rotation of generator orientation as a function of tonal frequency. Overall, the findings are consistent with the assumption of a homolog representation of tonal frequency in human and rhesus monkey EEG. PMID:27085798</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EGUGA..1210628T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EGUGA..1210628T"><span id="translatedtitle">Modeling the shallow gravity-driven flows as saturated binary mixtures over temporally varying <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tai, Yih-Chin; Kuo, Chih-Yu</p> <p>2010-05-01</p> <p>Based on the "shallow water models over arbitrary <span class="hlt">topography</span>" by Bouchut and Westdickenberg [2004], and the "Coulomb-mixture theory" by Iversion and Denlinger [2001], we propose a saturated binary mixture model over temporally varying <span class="hlt">topography</span>, where the effects of the entrainment and deposition are considered. Due to the deposition or erosion processes, the interface between the moving material and the stagnant base is a non-material singular surface that moves with its own velocity. Its motion is thus determined by the mass exchange between the flowing layer and the ground. Through the introduction of the unified coordinate method (e.g. Hui [2004, 2007]) and dimension analysis, the leading-order depth-integrated mass and momentum equations are presented in the time-dependent and <span class="hlt">topography</span>-fitted curvilinear coordinate system, where the evolving curvature effect is neatly included in the total derivative operator of the variable <span class="hlt">topography</span>-fitted coordinates. The motion of the basal interface is postulated by function of basal friction coefficient, sliding velocity, local thickness of the flowing layer and a threshold kinetic energy. A shock-capturing numerical scheme is implemented to solve the derived equation system (e.g. Tai and Kuo [2008] or Tai and Lin [2008]). And the key features are investigated and illustrated by the numerical results. References: [1] F. Bouchut and M. Westdickenberg, "Gravity driven shallow water models for arbitrary <span class="hlt">topography</span>." Commun. Math. Sci. 2, 359-389 (2004). [2] R.M. Iverson and R.P. Denlinger, "Flow of variably fluidized granular masses across three-dimensional terrain. Part 1 Coulomb mixture theory." J. Geophysical Research, 106, 537-552 (2001). [3] W.H. Hui, "A unified coordinates approach to computational Fluid <span class="hlt">dynamics</span>." J. Comput. and Applied Math., 163, 15-28 (2004). [4] W.H. Hui. "The unified coordinate system in computational fluid <span class="hlt">dynamics</span>." Commun. Comput. Phys., 2(4), 577-610 (2007). [5] Y.C. Tai and C.Y. Kuo, "A</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EGUGA..1214544C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EGUGA..1214544C"><span id="translatedtitle">Enabling Access to High-Resolution Lidar <span class="hlt">Topography</span> for Earth Science Research</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Crosby, Christopher; Nandigam, Viswanath; Arrowsmith, Ramon; Baru, Chaitan</p> <p>2010-05-01</p> <p>High-resolution <span class="hlt">topography</span> data acquired with lidar (light detection and ranging a.k.a. laser scanning) technology are revolutionizing the way we study the geomorphic processes acting along the Earth's surface. These data, acquired from either an airborne platform or from a tripod-mounted scanner, are emerging as a fundamental tool for research on a variety of topics ranging from earthquake hazards to ice sheet <span class="hlt">dynamics</span>. Lidar <span class="hlt">topography</span> data allow earth scientists to study the processes that contribute to landscape evolution at resolutions not previously possible yet essential for their appropriate representation. These datasets also have significant implications for earth science education and outreach because they provide an accurate digital representation of landforms and geologic hazards. However, along with the potential of lidar <span class="hlt">topography</span> comes an increase in the volume and complexity of data that must be efficiently managed, archived, distributed, processed and integrated in order for them to be of use to the community. A single lidar data acquisition may generate terabytes of data in the form of point clouds, digital elevation models (DEMs), and derivative imagery. This massive volume of data is often difficult to manage and poses significant distribution challenges when trying to allow access to the data for a large scientific user community. Furthermore, the datasets can be technically challenging to work with and may require specific software and computing resources that are not readily available to many users. The U.S. National Science Foundation (NSF)-funded Open<span class="hlt">Topography</span> Facility (http://www.opentopography.org) is an online data access and processing system designed to address the challenges posed by lidar data, and to democratize access to these data for the scientific user community. Open<span class="hlt">Topography</span> provides free, online access to lidar data in a number of forms, including raw lidar point cloud data, standard DEMs, and easily accessible Google</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMEP41B3535N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMEP41B3535N"><span id="translatedtitle"><span class="hlt">Topography</span> and Vegetation Characterization using Dual-Wavelength Airborne Lidar</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Neuenschwander, A. L.; Bradford, B.; Magruder, L. A.</p> <p>2014-12-01</p> <p>Monitoring Earth surface <span class="hlt">dynamics</span> at an ever increasing resolution has helped to support the characterization of local <span class="hlt">topography</span>, including vegetated and urban environments. Airborne remote sensing using light detection and ranging (LIDAR) is naturally suited to characterize vegetation and landscapes as it provides detailed three-dimensional spatial data with multiple elevation recordings for each laser pulse. The full waveform LIDAR receiver is unique in this aspect as it can capture and record the complete temporal history of the reflected signal, which contains detailed information about the structure of the objects and ground surfaces illuminated by the beam. This study examines the utility of co-collected, dual-wavelength, full waveform LIDAR data to characterize vegetation and landscapes through the extraction of waveform features, including total waveform energy, canopy energy distribution, and foliage penetration metrics. Assessments are performed using data collected in May 2014 over Monterey, CA, including the Naval Postgraduate School campus area as well as the Point Lobos State Natural Reserve situated on the Monterey coast. The surveys were performed with the Chiroptera dual-laser LIDAR mapping system from Airborne Hydrography AB (AHAB), which can collect both green (515nm) and near infrared (1064nm) waveforms simultaneously. Making use of the dual waveforms allows for detailed characterization of the vegetation and landscape not previously possible with airborne LIDAR.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APS..MARQ50011P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..MARQ50011P"><span id="translatedtitle">Renewable Interfaces: Surface <span class="hlt">Topography</span> Actuation for Complex Biological Adhesion Control</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pocivavsek, Luka; Ye, Sangho; Cao, Kathleen; Lee, Ka Yee C.; Velankar, Sachin; Wagner, William</p> <p>2015-03-01</p> <p>Controlling adhesion at biological interfaces is a complex problem with great biomedical importance. We use <span class="hlt">dynamic</span> wrinkling, generated with PDMS/UVO chemistry under different macroscopic strains (ɛij ~ 0 . 3), to create a mechanical interfacial term that frustrates particle adhesion. This device actuates surface <span class="hlt">topography</span> between flat (zero surface confinement χij) and wrinkled surfaces (χij ~(A / λ) 2 , where A and λ are wrinkle amplitude and wavelength, respectively), with a maximum rate of 0.6 Hz. Un-actuated PDMS placed in contact with whole sheep blood shows near total surface coverage with adhered platelets over 90 min. Actuation showed a nearly 100-fold decrease in platelet adhesion. Interestingly, topographic actuation is four times as effective compared to flat surface actuation in controlling platelet adhesion. Our model explores the competition between surface tension terms (Uγ = γɛij) and interfacial elastic terms (Uχ =Eij (t .ɛij2 +t3 . (χij /λ2)) generated because of actuation and wrinkling, where Eij is platelet modulus and t is characteristic platelet length scale. The condition for de-adhesion is Uχ >Uγ .</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/20304485','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/20304485"><span id="translatedtitle">Neuronal polarity selection by <span class="hlt">topography</span>-induced focal adhesion control.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ferrari, Aldo; Cecchini, Marco; Serresi, Michela; Faraci, Paolo; Pisignano, Dario; Beltram, Fabio</p> <p>2010-06-01</p> <p>Interaction between differentiating neurons and the extracellular environment guides the establishment of cell polarity during nervous system development. Developing neurons read the physical properties of the local substrate in a contact-dependent manner and retrieve essential guidance cues. In previous works we demonstrated that PC12 cell interaction with nanogratings (alternating lines of ridges and grooves of submicron size) promotes bipolarity and alignment to the substrate <span class="hlt">topography</span>. Here, we investigate the role of focal adhesions, cell contractility, and actin <span class="hlt">dynamics</span> in this process. Exploiting nanoimprint lithography techniques and a cyclic olefin copolymer, we engineered biocompatible nanostructured substrates designed for high-resolution live-cell microscopy. Our results reveal that neuronal polarization and contact guidance are based on a geometrical constraint of focal adhesions resulting in an angular modulation of their maturation and persistence. We report on ROCK1/2-myosin-II pathway activity and demonstrate that ROCK-mediated contractility contributes to polarity selection during neuronal differentiation. Importantly, the selection process confined the generation of actin-supported membrane protrusions and the initiation of new neurites at the poles. Maintenance of the established polarity was independent from NGF stimulation. Altogether our results imply that focal adhesions and cell contractility stably link the topographical configuration of the extracellular environment to a corresponding neuronal polarity state. PMID:20304485</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SPIE.9570E..1DS','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SPIE.9570E..1DS"><span id="translatedtitle">Clock time is <span class="hlt">absolute</span> and universal</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shen, Xinhang</p> <p>2015-09-01</p> <p>A critical error is found in the Special Theory of Relativity (STR): mixing up the concepts of the STR abstract time of a reference frame and the displayed time of a physical clock, which leads to use the properties of the abstract time to predict time dilation on physical clocks and all other physical processes. Actually, a clock can never directly measure the abstract time, but can only record the result of a physical process during a period of the abstract time such as the number of cycles of oscillation which is the multiplication of the abstract time and the frequency of oscillation. After Lorentz Transformation, the abstract time of a reference frame expands by a factor gamma, but the frequency of a clock decreases by the same factor gamma, and the resulting multiplication i.e. the displayed time of a moving clock remains unchanged. That is, the displayed time of any physical clock is an invariant of Lorentz Transformation. The Lorentz invariance of the displayed times of clocks can further prove within the framework of STR our earth based standard physical time is <span class="hlt">absolute</span>, universal and independent of inertial reference frames as confirmed by both the physical fact of the universal synchronization of clocks on the GPS satellites and clocks on the earth, and the theoretical existence of the <span class="hlt">absolute</span> and universal Galilean time in STR which has proved that time dilation and space contraction are pure illusions of STR. The existence of the <span class="hlt">absolute</span> and universal time in STR has directly denied that the reference frame dependent abstract time of STR is the physical time, and therefore, STR is wrong and all its predictions can never happen in the physical world.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20140005478&hterms=climate+change&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dclimate%2Bchange','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20140005478&hterms=climate+change&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dclimate%2Bchange"><span id="translatedtitle">Achieving Climate Change <span class="hlt">Absolute</span> Accuracy in Orbit</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wielicki, Bruce A.; Young, D. F.; Mlynczak, M. G.; Thome, K. J; Leroy, S.; Corliss, J.; Anderson, J. G.; Ao, C. O.; Bantges, R.; Best, F.; Bowman, K.; Brindley, H.; Butler, J. J.; Collins, W.; Dykema, J. A.; Doelling, D. R.; Feldman, D. R.; Fox, N.; Huang, X.; Holz, R.; Huang, Y.; Jennings, D.; Jin, Z.; Johnson, D. G.; Jucks, K.; Kato, S.; Kratz, D. P.; Liu, X.; Lukashin, C.; Mannucci, A. J.; Phojanamongkolkij, N.; Roithmayr, C. M.; Sandford, S.; Taylor, P. C.; Xiong, X.</p> <p>2013-01-01</p> <p>The Climate <span class="hlt">Absolute</span> Radiance and Refractivity Observatory (CLARREO) mission will provide a calibration laboratory in orbit for the purpose of accurately measuring and attributing climate change. CLARREO measurements establish new climate change benchmarks with high <span class="hlt">absolute</span> radiometric accuracy and high statistical confidence across a wide range of essential climate variables. CLARREO's inherently high <span class="hlt">absolute</span> accuracy will be verified and traceable on orbit to Système Internationale (SI) units. The benchmarks established by CLARREO will be critical for assessing changes in the Earth system and climate model predictive capabilities for decades into the future as society works to meet the challenge of optimizing strategies for mitigating and adapting to climate change. The CLARREO benchmarks are derived from measurements of the Earth's thermal infrared spectrum (5-50 micron), the spectrum of solar radiation reflected by the Earth and its atmosphere (320-2300 nm), and radio occultation refractivity from which accurate temperature profiles are derived. The mission has the ability to provide new spectral fingerprints of climate change, as well as to provide the first orbiting radiometer with accuracy sufficient to serve as the reference transfer standard for other space sensors, in essence serving as a "NIST [National Institute of Standards and Technology] in orbit." CLARREO will greatly improve the accuracy and relevance of a wide range of space-borne instruments for decadal climate change. Finally, CLARREO has developed new metrics and methods for determining the accuracy requirements of climate observations for a wide range of climate variables and uncertainty sources. These methods should be useful for improving our understanding of observing requirements for most climate change observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1989ngs..rept.....P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1989ngs..rept.....P"><span id="translatedtitle">The National Geodetic Survey <span class="hlt">absolute</span> gravity program</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Peter, George; Moose, Robert E.; Wessells, Claude W.</p> <p>1989-03-01</p> <p>The National Geodetic Survey <span class="hlt">absolute</span> gravity program will utilize the high precision afforded by the JILAG-4 instrument to support geodetic and geophysical research, which involves studies of vertical motions, identification and modeling of other temporal variations, and establishment of reference values. The scientific rationale of these objectives is given, the procedures used to collect gravity and environmental data in the field are defined, and the steps necessary to correct and remove unwanted environmental effects are stated. In addition, site selection criteria, methods of concomitant environmental data collection and relative gravity observations, and schedule and logistics are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19900066048&hterms=saturn+rings&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dsaturn%2Brings','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19900066048&hterms=saturn+rings&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dsaturn%2Brings"><span id="translatedtitle">An <span class="hlt">absolute</span> radius scale for Saturn's rings</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Nicholson, Philip D.; Cooke, Maren L.; Pelton, Emily</p> <p>1990-01-01</p> <p>Radio and stellar occultation observations of Saturn's rings made by the Voyager spacecraft are discussed. The data reveal systematic discrepancies of almost 10 km in some parts of the rings, limiting some of the investigations. A revised solution for Saturn's rotation pole has been proposed which removes the discrepancies between the stellar and radio occultation profiles. Corrections to previously published radii vary from -2 to -10 km for the radio occultation, and +5 to -6 km for the stellar occultation. An examination of spiral density waves in the outer A Ring supports that the revised <span class="hlt">absolute</span> radii are in error by no more than 2 km.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMGC21C..07F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMGC21C..07F"><span id="translatedtitle">Characterization of the DARA solar <span class="hlt">absolute</span> radiometer</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Finsterle, W.; Suter, M.; Fehlmann, A.; Kopp, G.</p> <p>2011-12-01</p> <p>The Davos <span class="hlt">Absolute</span> Radiometer (DARA) prototype is an Electrical Substitution Radiometer (ESR) which has been developed as a successor of the PMO6 type on future space missions and ground based TSI measurements. The DARA implements an improved thermal design of the cavity detector and heat sink assembly to minimize air-vacuum differences and to maximize thermal symmetry of measuring and compensating cavity. The DARA also employs an inverted viewing geometry to reduce internal stray light. We will report on the characterization and calibration experiments which were carried out at PMOD/WRC and LASP (TRF).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/15020268','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/15020268"><span id="translatedtitle"><span class="hlt">Absolute</span> calibration of the Auger fluorescence detectors</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Bauleo, P.; Brack, J.; Garrard, L.; Harton, J.; Knapik, R.; Meyhandan, R.; Rovero, A.C.; Tamashiro, A.; Warner, D.</p> <p>2005-07-01</p> <p><span class="hlt">Absolute</span> calibration of the Pierre Auger Observatory fluorescence detectors uses a light source at the telescope aperture. The technique accounts for the combined effects of all detector components in a single measurement. The calibrated 2.5 m diameter light source fills the aperture, providing uniform illumination to each pixel. The known flux from the light source and the response of the acquisition system give the required calibration for each pixel. In the lab, light source uniformity is studied using CCD images and the intensity is measured relative to NIST-calibrated photodiodes. Overall uncertainties are presently 12%, and are dominated by systematics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/284112','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/284112"><span id="translatedtitle"><span class="hlt">Absolute</span> angular positioning in ultrahigh vacuum</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Schief, H.; Marsico, V.; Kern, K.</p> <p>1996-05-01</p> <p>Commercially available angular resolvers, which are routinely used in machine tools and robotics, are modified and adapted to be used under ultrahigh-vacuum (UHV) conditions. They provide straightforward and reliable measurements of angular positions for any kind of UHV sample manipulators. The corresponding <span class="hlt">absolute</span> reproducibility is on the order of 0.005{degree}, whereas the relative resolution is better than 0.001{degree}, as demonstrated by high-resolution helium-reflectivity measurements. The mechanical setup and possible applications are discussed. {copyright} {ital 1996 American Institute of Physics.}</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70010730','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70010730"><span id="translatedtitle"><span class="hlt">Absolute</span> method of measuring magnetic susceptibility</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Thorpe, A.; Senftle, F.E.</p> <p>1959-01-01</p> <p>An <span class="hlt">absolute</span> method of standardization and measurement of the magnetic susceptibility of small samples is presented which can be applied to most techniques based on the Faraday method. The fact that the susceptibility is a function of the area under the curve of sample displacement versus distance of the magnet from the sample, offers a simple method of measuring the susceptibility without recourse to a standard sample. Typical results on a few substances are compared with reported values, and an error of less than 2% can be achieved. ?? 1959 The American Institute of Physics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009acse.book..955S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009acse.book..955S"><span id="translatedtitle"><span class="hlt">Absolute</span> Priority for a Vehicle in VANET</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shirani, Rostam; Hendessi, Faramarz; Montazeri, Mohammad Ali; Sheikh Zefreh, Mohammad</p> <p></p> <p>In today's world, traffic jams waste hundreds of hours of our life. This causes many researchers try to resolve the problem with the idea of Intelligent Transportation System. For some applications like a travelling ambulance, it is important to reduce delay even for a second. In this paper, we propose a completely infrastructure-less approach for finding shortest path and controlling traffic light to provide <span class="hlt">absolute</span> priority for an emergency vehicle. We use the idea of vehicular ad-hoc networking to reduce the imposed travelling time. Then, we simulate our proposed protocol and compare it with a centrally controlled traffic light system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19760017027','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19760017027"><span id="translatedtitle">Influence of planetary-scale <span class="hlt">topography</span> on the diurnal thermal tide during the 1971 Martian dust storm</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Conrath, B. J.</p> <p>1976-01-01</p> <p>Data obtained with the Mariner 9 infrared spectroscopy experiment during the Martian Dust Storm of 1971 to 1972 are examined for evidence of topographic influence on the atmospheric thermal structure. Temperature perturbations which are well correlated with the planetary scale <span class="hlt">topography</span> are found superposed on the large amplitude diurnal thermal tide. Applications of tidal theory to the data indicate that the observed perturbations result from the kinematic interaction of the westward traveling diurnal wave with the large scale components of <span class="hlt">topography</span>. The dominant mode is excited by the wave-number two <span class="hlt">topography</span> component and is a vertically evanescent eastward traveling wave with an equivalent depth comparable to the atmospheric scale height. The principle <span class="hlt">dynamic</span> effect of this mode is the enhancement of the amplitude of the near-surface diurnal wind to over 40m/sec in limited areas near 30 deg south latitude. It appears likely that dust was injected into the atmosphere in these regions during the storm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2858020','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2858020"><span id="translatedtitle">Nano-<span class="hlt">topography</span> sensing by osteoclasts</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Geblinger, Dafna; Addadi, Lia; Geiger, Benjamin</p> <p>2010-01-01</p> <p>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 <span class="hlt">topography</span> 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. PMID:20375065</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4346041','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4346041"><span id="translatedtitle">Epitope <span class="hlt">topography</span> controls bioactivity in supramolecular nanofibers</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Sur, Shantanu; Tantakitti, Faifan; Matson, John B.; Stupp, Samuel I.</p> <p>2015-01-01</p> <p>Incorporating bioactivity into artificial scaffolds using peptide epitopes present in the extracellular matrix (ECM) is a well-known approach. A common strategy has involved epitopes that provide cells with attachment points and external cues through interaction with integrin receptors. Although a variety of bioactive sequences have been identified so far, less is known about their optimal display in a scaffold. We report here on the use of self-assembled peptide amphiphile (PA) nanofiber matrices to investigate the impact of spatial presentation of the fibronectin derived epitope RGDS on cell response. Using one, three, or five glycine residues, RGDS epitopes were systematically spaced out from the surface of the rigid nanofibers. We found that cell morphology was strongly affected by the separation of the epitope from the nanofiber surface, with the longest distance yielding the most cell-spreading, bundling of actin filaments, and a round-to-polygonal transformation of cell shape. Cell response to this type of epitope display was also accompanied with activated integrin-mediated signaling and formation of stronger adhesions between cells and substrate. Interestingly, unlike length, changing the molecular flexibility of the linker had minimal influence on cell behavior on the substrate for reasons that remain poorly understood. The use in this study of high persistence length nanofibers rather than common flexible polymers allows us to conclude that epitope <span class="hlt">topography</span> at the nanoscale structure of a scaffold influences its bioactive properties independent of epitope density and mechanical properties. PMID:25745558</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUFM.P41A0222C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUFM.P41A0222C"><span id="translatedtitle">Shape, <span class="hlt">Topography</span> and Roughness of 25143 Itokawa</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cheng, A. F.; Barnouin-Jha, O. S.</p> <p>2007-12-01</p> <p>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 <span class="hlt">topography</span> 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6873599','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6873599"><span id="translatedtitle">Inversion of <span class="hlt">topography</span> in Martian highland terrains</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>De Hon, R.A.</p> <p>1985-01-01</p> <p>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 <span class="hlt">topography</span> in which the originally elevated rim is reduced to negative relief.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/11308547','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/11308547"><span id="translatedtitle">Basins of attraction on random <span class="hlt">topography</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Schorghofer, N; Rothman, D H</p> <p>2001-02-01</p> <p>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 <span class="hlt">topography</span>. 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. PMID:11308547</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1989SPIE.1161..409K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1989SPIE.1161..409K"><span id="translatedtitle">Imaging, Reconstruction, And Display Of Corneal <span class="hlt">Topography</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Klyce, Stephen D.; Wilson, Steven E.</p> <p>1989-12-01</p> <p>The cornea is the major refractive element in the eye; even minor surface distortions can produce a significant reduction in visual acuity. Standard clinical methods used to evaluate corneal shape include keratometry, which assumes the cornea is ellipsoidal in shape, and photokeratoscopy, which images a series of concentric light rings on the corneal surface. These methods fail to document many of the corneal distortions that can degrade visual acuity. Algorithms have been developed to reconstruct the three dimensional shape of the cornea from keratoscope images, and to present these data in the clinically useful display of color-coded contour maps of corneal surface power. This approach has been implemented on a new generation video keratoscope system (Computed Anatomy, Inc.) with rapid automatic digitization of the image rings by a rule-based approach. The system has found clinical use in the early diagnosis of corneal shape anomalies such as keratoconus and contact lens-induced corneal warpage, in the evaluation of cataract and corneal transplant procedures, and in the assessment of corneal refractive surgical procedures. Currently, ray tracing techniques are being used to correlate corneal surface <span class="hlt">topography</span> with potential visual acuity in an effort to more fully understand the tolerances of corneal shape consistent with good vision and to help determine the site of dysfunction in the visually impaired.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19690000209','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19690000209"><span id="translatedtitle">Determination of the <span class="hlt">absolute</span> contours of optical flats</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Primak, W.</p> <p>1969-01-01</p> <p>Emersons procedure is used to determine true <span class="hlt">absolute</span> contours of optical flats. <span class="hlt">Absolute</span> contours of standard flats are determined and a comparison is then made between standard and unknown flats. Contour differences are determined by deviation of Fizeau fringe.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFM.P21B..07I&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFM.P21B..07I&link_type=ABSTRACT"><span id="translatedtitle">The Interior of Enceladus from Gravity and <span class="hlt">Topography</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Iess, L.</p> <p>2015-12-01</p> <p>The combination of gravity and <span class="hlt">topography</span> has been the method of choice to obtain quantitative information on the interior of Enceladus, but its application was challenging because of the small mass of the moon and the short gravitational interaction time with the Cassini spacecraft. The main observable quantity used in the estimation of the gravity field was the spacecraft range rate, measured by the antennas of NASA's Deep Space Network to an accuracy of about 0.03 mm/s (at 60 s integration time). In spite of these challenges and thanks to the careful design of three gravity flybys, Cassini was able to catch the essential features of Enceladus's gravity field, in particular to estimate its quadrupole and detect the sought-for hemispherical asymmetry [1]. Crucial for the correct fit of the Doppler data was the inclusion in the <span class="hlt">dynamical</span> model of the drag acceleration from the plume's neutral particles. Although the largest quadrupole coefficients indicate only a mild deviation from hydrostatic equilibrium (J2/C22=3.55±0.05), a reliable determination of the MOIF uses J3 to separate the hydrostatic and non-hydrostatic components of the quadrupole field. The application of this method results in a MOIF (0.336) compatible with a differentiated structure. (An admittance analysis leads to a similar value.) The magnitude and the sign of J3 indicate that the gravity anomaly associated to the striking topographic depression (-1 km) in the southern polar regions is largely compensated by denser material at depth. The obvious (but not the only) interpretation points to a liquid water mass, denser than the surrounding ice and sandwiched between the ice shell and the rocky core. The gravity field and the <span class="hlt">topography</span> provide also rough estimate of the size of the water mass and the depth at which it is located. Starting from the consideration that the hydrostatic J2/C22 ratio for a fast rotator like Enceladus is about 3.25 and not 10/3, a recent work [2] offers some adjustments</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6086416','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6086416"><span id="translatedtitle">Standardization of the cumulative <span class="hlt">absolute</span> velocity</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>O'Hara, T.F.; Jacobson, J.P. )</p> <p>1991-12-01</p> <p>EPRI NP-5930, A Criterion for Determining Exceedance of the Operating Basis Earthquake,'' was published in July 1988. As defined in that report, the Operating Basis Earthquake (OBE) is exceeded when both a response spectrum parameter and a second damage parameter, referred to as the Cumulative <span class="hlt">Absolute</span> Velocity (CAV), are exceeded. In the review process of the above report, it was noted that the calculation of CAV could be confounded by time history records of long duration containing low (nondamaging) acceleration. Therefore, it is necessary to standardize the method of calculating CAV to account for record length. This standardized methodology allows consistent comparisons between future CAV calculations and the adjusted CAV threshold value based upon applying the standardized methodology to the data set presented in EPRI NP-5930. The recommended method to standardize the CAV calculation is to window its calculation on a second-by-second basis for a given time history. If the <span class="hlt">absolute</span> acceleration exceeds 0.025g at any time during each one second interval, the earthquake records used in EPRI NP-5930 have been reanalyzed and the adjusted threshold of damage for CAV was found to be 0.16g-set.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/16231945','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/16231945"><span id="translatedtitle"><span class="hlt">Absolute</span> rates of hole transfer in DNA.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Senthilkumar, Kittusamy; Grozema, Ferdinand C; Guerra, Célia Fonseca; Bickelhaupt, F Matthias; Lewis, Frederick D; Berlin, Yuri A; Ratner, Mark A; Siebbeles, Laurens D A</p> <p>2005-10-26</p> <p><span class="hlt">Absolute</span> rates of hole transfer between guanine nucleobases separated by one or two A:T base pairs in stilbenedicarboxamide-linked DNA hairpins were obtained by improved kinetic analysis of experimental data. The charge-transfer rates in four different DNA sequences were calculated using a density-functional-based tight-binding model and a semiclassical superexchange model. Site energies and charge-transfer integrals were calculated directly as the diagonal and off-diagonal matrix elements of the Kohn-Sham Hamiltonian, respectively, for all possible combinations of nucleobases. Taking into account the Coulomb interaction between the negative charge on the stilbenedicarboxamide linker and the hole on the DNA strand as well as effects of base pair twisting, the relative order of the experimental rates for hole transfer in different hairpins could be reproduced by tight-binding calculations. To reproduce quantitatively the <span class="hlt">absolute</span> values of the measured rate constants, the effect of the reorganization energy was taken into account within the semiclassical superexchange model for charge transfer. The experimental rates could be reproduced with reorganization energies near 1 eV. The quantum chemical data obtained were used to discuss charge carrier mobility and hole-transport equilibria in DNA. PMID:16231945</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016APS..APRB16007K&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016APS..APRB16007K&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Absolute</span> Electron Extraction Efficiency of Liquid Xenon</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kamdin, Katayun; Mizrachi, Eli; Morad, James; Sorensen, Peter</p> <p>2016-03-01</p> <p>Dual phase liquid/gas xenon time projection chambers (TPCs) currently set the world's most sensitive limits on weakly interacting massive particles (WIMPs), a favored dark matter candidate. These detectors rely on extracting electrons from liquid xenon into gaseous xenon, where they produce proportional scintillation. The proportional scintillation from the extracted electrons serves to internally amplify the WIMP signal; even a single extracted electron is detectable. Credible dark matter searches can proceed with electron extraction efficiency (EEE) lower than 100%. However, electrons systematically left at the liquid/gas boundary are a concern. Possible effects include spontaneous single or multi-electron proportional scintillation signals in the gas, or charging of the liquid/gas interface or detector materials. Understanding EEE is consequently a serious concern for this class of rare event search detectors. Previous EEE measurements have mostly been relative, not <span class="hlt">absolute</span>, assuming efficiency plateaus at 100%. I will present an <span class="hlt">absolute</span> EEE measurement with a small liquid/gas xenon TPC test bed located at Lawrence Berkeley National Laboratory.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SPIE.9639E..06L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SPIE.9639E..06L"><span id="translatedtitle">Sentinel-2/MSI <span class="hlt">absolute</span> calibration: first results</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lonjou, V.; Lachérade, S.; Fougnie, B.; Gamet, P.; Marcq, S.; Raynaud, J.-L.; Tremas, T.</p> <p>2015-10-01</p> <p>Sentinel-2 is an optical imaging mission devoted to the operational monitoring of land and coastal areas. It is developed in partnership between the European Commission and the European Space Agency. The Sentinel-2 mission is based on a satellites constellation deployed in polar sun-synchronous orbit. It will offer a unique combination of global coverage with a wide field of view (290km), a high revisit (5 days with two satellites), a high resolution (10m, 20m and 60m) and multi-spectral imagery (13 spectral bands in visible and shortwave infra-red domains). CNES is involved in the instrument commissioning in collaboration with ESA. This paper reviews all the techniques that will be used to insure an <span class="hlt">absolute</span> calibration of the 13 spectral bands better than 5% (target 3%), and will present the first results if available. First, the nominal calibration technique, based on an on-board sun diffuser, is detailed. Then, we show how vicarious calibration methods based on acquisitions over natural targets (oceans, deserts, and Antarctica during winter) will be used to check and improve the accuracy of the <span class="hlt">absolute</span> calibration coefficients. Finally, the verification scheme, exploiting photometer in-situ measurements over Lacrau plain, is described. A synthesis, including spectral coherence, inter-methods agreement and temporal evolution, will conclude the paper.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1994AAS...18510401C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1994AAS...18510401C"><span id="translatedtitle"><span class="hlt">Absolute</span> Spectrophotometry of 237 Open Cluster Stars</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Clampitt, L.; Burstein, D.</p> <p>1994-12-01</p> <p>We present <span class="hlt">absolute</span> spectrophotometry of 237 stars in 7 nearby open clusters: Hyades, Pleiades, Alpha Persei, Praesepe, Coma Berenices, IC 4665, and M 39. The observations were taken using the Wampler single-channel scanner (Wampler 1966) on the Crossley 0.9m telescope at Lick Observatory from July 1973 through December 1974. 21 bandpasses spanning the spectral range 3500 Angstroms to 7780 Angstroms were observed for each star, with bandwiths ranging from 32Angstroms to 64 Angstroms. Data are standardized to the Hayes--Latham (1975) system. Our measurements are compared to filter colors on the Johnson BV, Stromgren ubvy, and Geneva U V B_1 B_2 V_1 G systems, as well as to spectrophotometry of a few stars published by Gunn, Stryker & Tinsley and in the Spectrophotometric Standards Catalog (Adelman; as distributed by the NSSDC). Both internal and external comparisons to the filter systems indicate a formal statistical accuracy per bandpass of 0.01 to 0.02 mag, with apparent larger ( ~ 0.03 mag) differences in <span class="hlt">absolute</span> calibration between this data set and existing spectrophotometry. These data will comprise part of the spectrophotometry that will be used to calibrate the Beijing-Arizona-Taipei-Connecticut Color Survey of the Sky (see separate paper by Burstein et al. at this meeting).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014SPIE.9204E..08R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014SPIE.9204E..08R"><span id="translatedtitle"><span class="hlt">Absolute</span> height measurement of specular surfaces with modified active fringe reflection photogrammetry</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ren, Hongyu; Jiang, Xiangqian; Gao, Feng; Zhang, Zonghua</p> <p>2014-07-01</p> <p>Deflectometric methods have been studied for more than a decade for slope measurement of specular freeform surfaces through utilization of the deformation of a sample pattern after reflection from a tested sample surface. Usually, these approaches require two-directional fringe patterns to be projected on a LCD screen or ground glass and require slope integration, which leads to some complexity for the whole measuring process. This paper proposes a new mathematical measurement model for measuring <span class="hlt">topography</span> information of freeform specular surfaces, which integrates a virtual reference specular surface into the method of active fringe reflection photogrammetry and presents a straight-forward relation between height of the tested surface and phase signals. This method only requires one direction of horizontal or vertical sinusoidal fringe patterns to be projected from a LCD screen, resulting in a significant reduction in capture time over established methods. Assuming the whole system has been precalibrated during the measurement process, the fringe patterns are captured separately via the virtual reference and detected freeform surfaces by a CCD camera. The reference phase can be solved according to the spatial geometric relation between the LCD screen and the CCD camera. The captured phases can be unwrapped with a heterodyne technique and optimum frequency selection method. Based on this calculated unwrapped-phase and that proposed mathematical model, <span class="hlt">absolute</span> height of the inspected surface can be computed. Simulated and experimental results show that this methodology can conveniently calculate <span class="hlt">topography</span> information for freeform and structured specular surfaces without integration and reconstruction processes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUFMIN51B0405A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUFMIN51B0405A"><span id="translatedtitle">The Global Multi-Resolution <span class="hlt">Topography</span> (GMRT) Synthesis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Arko, R.; Ryan, W.; Carbotte, S.; Melkonian, A.; Coplan, J.; O'Hara, S.; Chayes, D.; Weissel, R.; Goodwillie, A.; Ferrini, V.; Stroker, K.; Virden, W.</p> <p>2007-12-01</p> <p>Topographic maps provide a backdrop for research in nearly every earth science discipline. There is particular demand for bathymetry data in the ocean basins, where existing coverage is sparse. Ships and submersibles worldwide are rapidly acquiring large volumes of new data with modern swath mapping systems. The science community is best served by a global <span class="hlt">topography</span> compilation that is easily accessible, up-to-date, and delivers data in the highest possible (i.e. native) resolution. To meet this need, the NSF-supported Marine Geoscience Data System (MGDS; www.marine-geo.org) has partnered with the National Geophysical Data Center (NGDC; www.ngdc.noaa.gov) to produce the Global Multi-Resolution <span class="hlt">Topography</span> (GMRT) synthesis - a continuously updated digital elevation model that is accessible through Open Geospatial Consortium (OGC; www.opengeospatial.org) Web services. GMRT had its genesis in 1992 with the NSF RIDGE Multibeam Synthesis (RMBS); later grew to include the Antarctic Multibeam Synthesis (AMBS); expanded again to include the NSF Ridge 2000 and MARGINS programs; and finally emerged as a global compilation in 2005 with the NSF Legacy of Ocean Exploration (LOE) project. The LOE project forged a permanent partnership between MGDS and NGDC, in which swath bathymetry data sets are routinely published and exchanged via the Open Archives Initiative Protocol for Metadata Harvesting (OAI-PMH; www.openarchives.org). GMRT includes both color-shaded relief images and underlying elevation values at ten different resolutions as high as 100m. New data are edited, gridded, and tiled using tools originally developed by William Haxby at Lamont-Doherty Earth Observatory. Global and regional data sources include the NASA Shuttle Radar <span class="hlt">Topography</span> Mission (SRTM; http://www.jpl.nasa.gov/srtm/); Smith & Sandwell Satellite Predicted Bathymetry (http://topex.ucsd.edu/marine_topo/); SCAR Subglacial Topographic Model of the Antarctic (BEDMAP; http://www.antarctica.ac.uk/bedmap/); and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=VALUE+AND+ABSOLUTE&id=EJ920859','ERIC'); return false;" href="http://eric.ed.gov/?q=VALUE+AND+ABSOLUTE&id=EJ920859"><span id="translatedtitle">A Conceptual Approach to <span class="hlt">Absolute</span> Value Equations and Inequalities</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Ellis, Mark W.; Bryson, Janet L.</p> <p>2011-01-01</p> <p>The <span class="hlt">absolute</span> value learning objective in high school mathematics requires students to solve far more complex <span class="hlt">absolute</span> value equations and inequalities. When <span class="hlt">absolute</span> value problems become more complex, students often do not have sufficient conceptual understanding to make any sense of what is happening mathematically. The authors suggest that the…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=VALUE+AND+ABSOLUTE&id=EJ819063','ERIC'); return false;" href="http://eric.ed.gov/?q=VALUE+AND+ABSOLUTE&id=EJ819063"><span id="translatedtitle">Using, Seeing, Feeling, and Doing <span class="hlt">Absolute</span> Value for Deeper Understanding</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Ponce, Gregorio A.</p> <p>2008-01-01</p> <p>Using sticky notes and number lines, a hands-on activity is shared that anchors initial student thinking about <span class="hlt">absolute</span> value. The initial point of reference should help students successfully evaluate numeric problems involving <span class="hlt">absolute</span> value. They should also be able to solve <span class="hlt">absolute</span> value equations and inequalities that are typically found in…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title20-vol2/pdf/CFR-2010-title20-vol2-sec404-1205.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title20-vol2/pdf/CFR-2010-title20-vol2-sec404-1205.pdf"><span id="translatedtitle">20 CFR 404.1205 - <span class="hlt">Absolute</span> coverage groups.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2010&page.go=Go">Code of Federal Regulations, 2010 CFR</a></p> <p></p> <p>2010-04-01</p> <p>... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false <span class="hlt">Absolute</span> coverage groups. 404.1205 Section... INSURANCE (1950- ) Coverage of Employees of State and Local Governments What Groups of Employees May Be Covered § 404.1205 <span class="hlt">Absolute</span> coverage groups. (a) General. An <span class="hlt">absolute</span> coverage group is a...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20020087613&hterms=Kucinskas&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DKucinskas','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20020087613&hterms=Kucinskas&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DKucinskas"><span id="translatedtitle">An Improved 360 Degree and Order Model of Venus <span class="hlt">Topography</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rappaport, Nicole J.; Konopliv, Alex S.; Kucinskas, Algis B.; Ford, Peter G.</p> <p>1999-01-01</p> <p>We present an improved 360 degree and order spherical harmonic solution for Venus' <span class="hlt">topography</span>. The new model uses the most recent set of Venus altimetry data with spacecraft positions derived from a recent high resolution gravity model. Geometric analysis indicates that the offset between the center of mass and center of figure of Venus is about 10 times smaller than that for the Earth, the Moon, or Mars. Statistical analyses confirm that the RMS <span class="hlt">topography</span> follows a power law over the central part of the spectrum. Compared to the previous <span class="hlt">topography</span> model, the new model is more highly correlated with Venus' harmonic gravity field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PhRvE..90a2409A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PhRvE..90a2409A"><span id="translatedtitle">Dewetting of evaporating thin films over nanometer-scale <span class="hlt">topographies</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Akbarzadeh, A. M.; Moosavi, A.; Moghimi Kheirabadi, A.</p> <p>2014-07-01</p> <p>A lubrication model is used to study dewetting of an evaporating thin film layer over a solid substrate with a nanometer-scale <span class="hlt">topography</span>. The effects of the geometry of the <span class="hlt">topography</span>, the contact angle, the film thickness, and the slippage on the dewetting have been studied. Our results reveal that the evaporation enhances the dewetting process and reduces the depinning time over the <span class="hlt">topography</span>. Also it is shown that the depinning time is inversely proportional to the slippage and increasing the contact angle may considerably reduce the depinning time, while the film thickness increases the depinning time.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999Icar..139...19R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999Icar..139...19R"><span id="translatedtitle">An Improved 360 Degree and Order Model of Venus <span class="hlt">Topography</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rappaport, Nicole J.; Konopliv, Alex S.; Kucinskas, Algis B.; Ford, Peter G.</p> <p>1999-05-01</p> <p>We present an improved 360 degree and order spherical harmonic solution for Venus' <span class="hlt">topography</span>. The new model uses the most recent set of Venus altimetry data with spacecraft positions derived from a recent high resolution gravity model. Geometric analysis indicates that the offset between the center of mass and center of figure of Venus is about 10 times smaller than that for the Earth, the Moon, or Mars. Statistical analyses confirm that the RMS <span class="hlt">topography</span> follows a power law over the central part of the spectrum. Compared to the previous <span class="hlt">topography</span> model, the new model is more highly correlated with Venus' harmonic gravity field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=PIA02764&hterms=salt+water+salty&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dsalt%2Bwater%2Bsalty','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=PIA02764&hterms=salt+water+salty&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dsalt%2Bwater%2Bsalty"><span id="translatedtitle">SRTM Anaglyph: Inverted <span class="hlt">Topography</span>, Patagonia, Argentina</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2000-01-01</p> <p><p/> The Meseta de Somuncura is a broad plateau capped by basalt. Near its western edge is evidence of multiple volcanic events and a complex erosion history. Most notable are the long, narrow, and winding lava flows that run across most of the right side of the image. These formed from low-viscosity lava that flowed down gullies over fairly flat terrain. Later, erosion of the landscape continued, and the solidified flows were more resistant than the older surrounding rocks. Consequently, the flows became the ridges we see here. This natural process of converting gullies to ridges is called topographic inversion. See image PIA02755 (upper left corner) for a good example of topographic inversion in its earlier stages.<p/>Other features seen here include numerous and varied closed depressions. The regional drainage is not well integrated, but instead the drainage ends up in salty lakes (dark water, some with bright shores). Wind streaks indicate that winds blow toward the east (right) and blow salt grains off the lake beds when dry. The bowtie pattern in the upper left has resulted from differing grazing practices among fenced fields.<p/>This anaglyph was generated by first draping a Landsat Thematic Mapper image over a topographic map from the Shuttle Radar <span class="hlt">Topography</span> Mission, then producing the two differing perspectives, one for each eye. When viewed through special glasses, the result is a vertically exaggerated view of the Earth's surface in its full three dimensions. Anaglyph glasses cover the left eye with a red filter and the right eye with a blue filter.<p/>Landsat satellites have provided visible light and infrared images of the Earth continuously since 1972. SRTM topographic data match the 30-meter (99-foot) spatial resolution of most Landsat images and provide a valuable complement for studying the historic and growing Landsat data archive. The Landsat 7 Thematic Mapper image used here was provided to the SRTM project by the United States Geological</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=PIA10143&hterms=Spider&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DSpider','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=PIA10143&hterms=Spider&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DSpider"><span id="translatedtitle">Science in Motion: Isolated Araneiform <span class="hlt">Topography</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2007-01-01</p> <p><p/> [figure removed for brevity, see original site] Figure 1 <p/> Have you ever found that to describe something you had to go to the dictionary and search for just the right word? <p/> The south polar terrain is so full of unearthly features that we had to visit Mr. Webster to find a suitable term. 'Araneiform' means 'spider-like'. These are channels that are carved in the surface by carbon dioxide gas. We do not have this process on Earth. <p/> The channels are somewhat radially organized (figure 1) and widen and deepen as they converge. In the past we've just refered to them as 'spiders.' 'Isolated araneiform <span class="hlt">topography</span>' means that our features look like spiders that are not in contact with each other. <p/> Observation Geometry Image PSP_003087_0930 was taken by the High Resolution Imaging Science Experiment (HiRISE) camera onboard the Mars Reconnaissance Orbiter spacecraft on 24-Mar-2007. The complete image is centered at -87.1 degrees latitude, 126.3 degrees East longitude. The range to the target site was 244.4 km (152.8 miles). At this distance the image scale is 24.5 cm/pixel (with 1 x 1 binning) so objects 73 cm across are resolved. The image shown here has been map-projected to 25 cm/pixel . The image was taken at a local Mars time of 08:22 PM and the scene is illuminated from the west with a solar incidence angle of 81 degrees, thus the sun was about 9 degrees above the horizon. At a solar longitude of 206.4 degrees, the season on Mars is Northern Autumn.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4736031','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4736031"><span id="translatedtitle">Epithelial <span class="hlt">topography</span> for repetitive tooth formation</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Gaete, Marcia; Fons, Juan Manuel; Popa, Elena Mădălina; Chatzeli, Lemonia; Tucker, Abigail S.</p> <p>2015-01-01</p> <p>ABSTRACT During the formation of repetitive ectodermally derived organs such as mammary glands, lateral line and teeth, the tissue primordium iteratively initiates new structures. In the case of successional molar development, new teeth appear sequentially in the posterior region of the jaw from Sox2+ cells in association with the posterior aspect of a pre-existing tooth. The sequence of molar development is well known, however, the epithelial <span class="hlt">topography</span> involved in the formation of a new tooth is unclear. Here, we have examined the morphology of the molar dental epithelium and its development at different stages in the mouse in vivo and in molar explants. Using regional lineage tracing we show that within the posterior tail of the first molar the primordium for the second and third molar are organized in a row, with the tail remaining in connection with the surface, where a furrow is observed. The morphology and Sox2 expression of the tail retains characteristics reminiscent of the earlier stages of tooth development, such that position along the A-P axes of the tail correlates with different temporal stages. Sox9, a stem/progenitor cell marker in other organs, is expressed mainly in the suprabasal epithelium complementary with Sox2 expression. This Sox2 and Sox9 expressing molar tail contains actively proliferating cells with mitosis following an apico-basal direction. Snail2, a transcription factor implicated in cell migration, is expressed at high levels in the tip of the molar tail while E-cadherin and laminin are decreased. In conclusion, our studies propose a model in which the epithelium of the molar tail can grow by posterior movement of epithelial cells followed by infolding and stratification involving a population of Sox2+/Sox9+ cells. PMID:26538639</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26538639','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26538639"><span id="translatedtitle">Epithelial <span class="hlt">topography</span> for repetitive tooth formation.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gaete, Marcia; Fons, Juan Manuel; Popa, Elena Mădălina; Chatzeli, Lemonia; Tucker, Abigail S</p> <p>2015-01-01</p> <p>During the formation of repetitive ectodermally derived organs such as mammary glands, lateral line and teeth, the tissue primordium iteratively initiates new structures. In the case of successional molar development, new teeth appear sequentially in the posterior region of the jaw from Sox2(+) cells in association with the posterior aspect of a pre-existing tooth. The sequence of molar development is well known, however, the epithelial <span class="hlt">topography</span> involved in the formation of a new tooth is unclear. Here, we have examined the morphology of the molar dental epithelium and its development at different stages in the mouse in vivo and in molar explants. Using regional lineage tracing we show that within the posterior tail of the first molar the primordium for the second and third molar are organized in a row, with the tail remaining in connection with the surface, where a furrow is observed. The morphology and Sox2 expression of the tail retains characteristics reminiscent of the earlier stages of tooth development, such that position along the A-P axes of the tail correlates with different temporal stages. Sox9, a stem/progenitor cell marker in other organs, is expressed mainly in the suprabasal epithelium complementary with Sox2 expression. This Sox2 and Sox9 expressing molar tail contains actively proliferating cells with mitosis following an apico-basal direction. Snail2, a transcription factor implicated in cell migration, is expressed at high levels in the tip of the molar tail while E-cadherin and laminin are decreased. In conclusion, our studies propose a model in which the epithelium of the molar tail can grow by posterior movement of epithelial cells followed by infolding and stratification involving a population of Sox2(+)/Sox9(+) cells. PMID:26538639</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=money+AND+manipulation&id=EJ808734','ERIC'); return false;" href="http://eric.ed.gov/?q=money+AND+manipulation&id=EJ808734"><span id="translatedtitle">Use of <span class="hlt">Absolute</span> and Comparative Performance Feedback in <span class="hlt">Absolute</span> and Comparative Judgments and Decisions</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Moore, Don A.; Klein, William M. P.</p> <p>2008-01-01</p> <p>Which matters more--beliefs about <span class="hlt">absolute</span> ability or ability relative to others? This study set out to compare the effects of such beliefs on satisfaction with performance, self-evaluations, and bets on future performance. In Experiment 1, undergraduate participants were told they had answered 20% correct, 80% correct, or were not given their…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JVGR..278...25D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JVGR..278...25D"><span id="translatedtitle">Pyroclastic density currents and local <span class="hlt">topography</span> as seen with the conveyer model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Doronzo, Domenico M.; Dellino, Pierfrancesco</p> <p>2014-05-01</p> <p>Pyroclastic density currents (PDCs) are multiphase flows generated during explosive volcanic eruptions, and they move down the volcano, and over the surrounding <span class="hlt">topography</span>. The flow-<span class="hlt">topography</span> interaction can play a fundamental role in the sedimentary processes, and in the resulting deposit facies architecture, as well as can play a dramatic role in the flow behavior, and in the associated volcanic hazard. This paper aims at discussing the PDC-<span class="hlt">topography</span> interaction theme from the viewpoint of both deposits and flow structure, by accounting for appropriate literature, and revising the concepts in light of the theoretical conveyer model of Doronzo and Dellino (2013) on sedimentation and deposition in particulate density currents. First the effects, then the causes of the flow-<span class="hlt">topography</span> interaction are discussed, in order to follow the historical development of theme concepts. The discussion is relative in terms of inertial and forced currents, which are defined on the basis of a dimensionless quantity (SD) representing the conservation of mass. Momentum equation relating depositional unit thickness, flow shear velocity, and density contrast shows that the flow is the cause of PDC motion, whereas the density contrast sustains the momentum, and the deposits are the process effect. In particular, the flow structure is described into three parts, flow-substrate boundary zone, boundary layer (lower part), and wake region (upper part) of the current. The facies architecture of PDC deposits, and the volcanic hazard depend on fluid <span class="hlt">dynamic</span> and hydraulic behavior represented, in light of the conveyer model, by the balance of sedimentation and deposition rates through transport and erosion (“sedimentation-deposition” ratio, SD). This balance acts between flow-substrate boundary zone and boundary layer. The paper discussion mainly applies to small-to-intermediate volume eruptions. Field and modeling examples of Vulcano tuff cone and Colli Albani maar (Italy) constrain the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMEP53A3606G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMEP53A3606G"><span id="translatedtitle">Re-Envisioning Cross Sectional Hydraulic Geometry as Spatially Explicit Hydraulic <span class="hlt">Topography</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gonzalez, R. L.; Pasternack, G. B.</p> <p>2014-12-01</p> <p> 50 <span class="hlt">absolute</span> percent error with respect to the spatially explicit hydraulic <span class="hlt">topography</span> approach. Although traditional transect-based sampling may be viable for certain uses, percent errors of this magnitude could still compromise engineering applications in river management and training works.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3619386','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3619386"><span id="translatedtitle">Engineering microscale <span class="hlt">topographies</span> to control the cell–substrate interface</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Nikkhah, Mehdi; Edalat, Faramarz; Manoucheri, Sam; Khademhosseini, Ali</p> <p>2013-01-01</p> <p>Cells in their in vivo microenvironment constantly encounter and respond to a multitude of signals. While the role of biochemical signals has long been appreciated, the importance of biophysical signals has only recently been investigated. Biophysical cues are presented in different forms including <span class="hlt">topography</span> and mechanical stiffness imparted by the extracellular matrix and adjoining cells. Microfabrication technologies have allowed for the generation of biomaterials with microscale <span class="hlt">topographies</span> to study the effect of biophysical cues on cellular function at the cell–substrate interface. <span class="hlt">Topographies</span> of different geometries and with varying microscale dimensions have been used to better understand cell adhesion, migration, and differentiation at the cellular and sub-cellular scales. Furthermore, quantification of cell-generated forces has been illustrated with micropillar <span class="hlt">topographies</span> to shed light on the process of mechanotransduction. In this review, we highlight recent advances made in these areas and how they have been utilized for neural, cardiac, and musculoskeletal tissue engineering application. PMID:22521491</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19890056768&hterms=Mackenzie&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DMackenzie','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19890056768&hterms=Mackenzie&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DMackenzie"><span id="translatedtitle">Geoid height versus <span class="hlt">topography</span> for oceanic plateaus and swells</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sandwell, David T.; Mackenzie, Kevin R.</p> <p>1989-01-01</p> <p>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 <span class="hlt">topography</span> is examined using Airy and thermal compensation models. It is shown that geoid height is linearly related to <span class="hlt">topography</span> between wavelengths of 400 and 4000 m as predicted by isostatic compensation models. The geoid/<span class="hlt">topography</span> ratio is dependent on the average depth of compensation. The intermediate geoid/<span class="hlt">topography</span> 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SuTMP...3a5007A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SuTMP...3a5007A"><span id="translatedtitle">Surface <span class="hlt">topography</span> and the impact on fatigue performance</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ardi, D. T.; Li, Y. G.; Chan, K. H. K.; Blunt, L.; Bache, M. R.</p> <p>2015-03-01</p> <p>Areal characterization was applied to plain fatigue specimens manufactured from a nickel-based superalloy, Alloy 720Li, to determine the impact of machined/finished surface <span class="hlt">topography</span> on fatigue performance of this material. Samples were subjected to fatigue testing in the as-turned and shot peened conditions to study the interaction between residual stresses and <span class="hlt">topography</span> in influencing the fatigue performance. The turning process was deliberately manipulated to produce three distinct finishes which were subsequently given an identical shot peening, resulting in six grades of surface <span class="hlt">topography</span>. Surface <span class="hlt">topography</span> was found to influence fatigue even in the presence of peened compressive residual stresses by promoting crack initiation at valley sites. Both the roughness amplitude and spatial characteristics of the surface were found to be important when correlating to fatigue performance.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4557346','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4557346"><span id="translatedtitle">Tectonic control on the persistence of glacially sculpted <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Prasicek, Günther; Larsen, Isaac J.; Montgomery, David R.</p> <p>2015-01-01</p> <p>One of the most fundamental insights for understanding how landscapes evolve is based on determining the extent to which <span class="hlt">topography</span> was shaped by glaciers or by rivers. More than 104 years after the last major glaciation the <span class="hlt">topography</span> of mountain ranges worldwide remains dominated by characteristic glacial landforms such as U-shaped valleys, but an understanding of the persistence of such landforms is lacking. Here we use digital topographic data to analyse valley shapes at sites worldwide to demonstrate that the persistence of U-shaped valleys is controlled by the erosional response to tectonic forcing. Our findings indicate that glacial <span class="hlt">topography</span> in Earth's most rapidly uplifting mountain ranges is rapidly replaced by fluvial <span class="hlt">topography</span> and hence valley forms do not reflect the cumulative action of multiple glacial periods, implying that the classic physiographic signature of glaciated landscapes is best expressed in, and indeed limited by, the extent of relatively low-uplift terrain. PMID:26271245</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.usgs.gov/ds/674/','USGSPUBS'); return false;" href="http://pubs.usgs.gov/ds/674/"><span id="translatedtitle">EAARL coastal <span class="hlt">topography</span>--North Shore, Lake Pontchartrain, Louisiana, 2010</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Bonisteel-Cormier, J.M.; Nayegandhi, Amar; Fredericks, Xan; Wright, C.W.; Brock, J.C.; Nagle, D.B.; Vivekanandan, Saisudha; Barras, J.A.</p> <p>2012-01-01</p> <p>This DVD contains lidar-derived coastal <span class="hlt">topography</span> GIS datasets of a portion of the north shore of Lake Pontchartrain, Louisiana. These datasets were acquired on February 28, March 1, and March 5, 2010.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=306874','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=306874"><span id="translatedtitle">Influence of local <span class="hlt">topography</span> on precision irrigation management</span></a></p> <p><a target="_blank" href="http://www.ars.usda.gov/services/TekTran.htm">Technology Transfer Automated Retrieval System (TEKTRAN)</a></p> <p></p> <p></p> <p>Precision irrigation management is currently accomplished using spatial information about soil properties through soil series maps or electrical conductivity (EC measurements. Crop yield, however, is consistently influenced by local <span class="hlt">topography</span>, both in rain-fed and irrigated environments. Utilizing ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('//www.loc.gov/pictures/collection/hh/item/pa0105.photos.141202p/','SCIGOV-HHH'); return false;" href="//www.loc.gov/pictures/collection/hh/item/pa0105.photos.141202p/"><span id="translatedtitle">2. GENERAL VIEW SHOWING RELATION OF BRIDGE TO THE <span class="hlt">TOPOGRAPHY</span> ...</span></a></p> <p><a target="_blank" href="http://www.loc.gov/pictures/collection/hh/">Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey</a></p> <p></p> <p></p> <p>2. GENERAL VIEW SHOWING RELATION OF BRIDGE TO THE <span class="hlt">TOPOGRAPHY</span> OF THE APPROACH ROAD. - Speicher Bridge, Church Road over Tulpehocken Creek between Penn & North Heidelberg Townships, Bernville, Berks County, PA</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('//www.loc.gov/pictures/collection/hh/item/wa0270.photos.168461p/','SCIGOV-HHH'); return false;" href="//www.loc.gov/pictures/collection/hh/item/wa0270.photos.168461p/"><span id="translatedtitle">23. SPILLWAY NO. 1 LOWER END <span class="hlt">TOPOGRAPHY</span> AND SECTIONS. ...</span></a></p> <p><a target="_blank" href="http://www.loc.gov/pictures/collection/hh/">Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey</a></p> <p></p> <p></p> <p>23. SPILLWAY NO. 1 - LOWER END <span class="hlt">TOPOGRAPHY</span> 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</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2731455','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2731455"><span id="translatedtitle">Stimulus control <span class="hlt">topography</span> coherence theory: Foundations and extensions</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>McIlvane, William J.; Dube, William V.</p> <p>2003-01-01</p> <p>Stimulus control <span class="hlt">topography</span> refers to qualitative differences among members of a functional stimulus class. Stimulus control <span class="hlt">topography</span> 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 <span class="hlt">topography</span> 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 <span class="hlt">topography</span> coherence analysis of processes involved in discriminated and generalized operants. ImagesFigure 3Figure 5 PMID:22478402</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26271245','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26271245"><span id="translatedtitle">Tectonic control on the persistence of glacially sculpted <span class="hlt">topography</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Prasicek, Günther; Larsen, Isaac J; Montgomery, David R</p> <p>2015-01-01</p> <p>One of the most fundamental insights for understanding how landscapes evolve is based on determining the extent to which <span class="hlt">topography</span> was shaped by glaciers or by rivers. More than 10(4) years after the last major glaciation the <span class="hlt">topography</span> of mountain ranges worldwide remains dominated by characteristic glacial landforms such as U-shaped valleys, but an understanding of the persistence of such landforms is lacking. Here we use digital topographic data to analyse valley shapes at sites worldwide to demonstrate that the persistence of U-shaped valleys is controlled by the erosional response to tectonic forcing. Our findings indicate that glacial <span class="hlt">topography</span> in Earth's most rapidly uplifting mountain ranges is rapidly replaced by fluvial <span class="hlt">topography</span> and hence valley forms do not reflect the cumulative action of multiple glacial periods, implying that the classic physiographic signature of glaciated landscapes is best expressed in, and indeed limited by, the extent of relatively low-uplift terrain. PMID:26271245</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19730001883','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19730001883"><span id="translatedtitle">Calculation of irrotational wind pattern with application to Cleveland <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Siegel, R.</p> <p>1972-01-01</p> <p>Small perturbation theory is applied to compute the deflection of the wind blowing across land that has an irregular <span class="hlt">topography</span>. As an illustration, the method is applied first to the flow around a single hill of Gaussian profile. Then calculations are made for the irregular <span class="hlt">topography</span> on the east side of Cleveland where the elevation changes by several hundred feet. It was found that the <span class="hlt">topography</span> produced small wind deflections that would not be of practical importance in air pollution dispersion studies. The calculations were for a neutrally stable atmosphere. Although they are not investigated here, other factors such as thermal stratification of the atmosphere, diurnal variations, and convection currents resulting from the proximity of Lake Erie and the city heat island effect are expected to be more significant than the influence of <span class="hlt">topography</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19820002595','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19820002595"><span id="translatedtitle">MAGSAT: Vector magnetometer <span class="hlt">absolute</span> sensor alignment determination</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Acuna, M. H.</p> <p>1981-01-01</p> <p>A procedure is described for accurately determining the <span class="hlt">absolute</span> alignment of the magnetic axes of a triaxial magnetometer sensor with respect to an external, fixed, reference coordinate system. The method does not require that the magnetic field vector orientation, as generated by a triaxial calibration coil system, be known to better than a few degrees from its true position, and minimizes the number of positions through which a sensor assembly must be rotated to obtain a solution. Computer simulations show that accuracies of better than 0.4 seconds of arc can be achieved under typical test conditions associated with existing magnetic test facilities. The basic approach is similar in nature to that presented by McPherron and Snare (1978) except that only three sensor positions are required and the system of equations to be solved is considerably simplified. Applications of the method to the case of the MAGSAT Vector Magnetometer are presented and the problems encountered discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ChJOL.tmp...41Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ChJOL.tmp...41Y"><span id="translatedtitle"><span class="hlt">Absolute</span> geostrophic currents in global tropical oceans</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yang, Lina; Yuan, Dongliang</p> <p>2016-03-01</p> <p>A set of <span class="hlt">absolute</span> geostrophic current (AGC) data for the period January 2004 to December 2012 are calculated using the P-vector method based on monthly gridded Argo profiles in the world tropical oceans. The AGCs agree well with altimeter geostrophic currents, Ocean Surface Current Analysis-Real time currents, and moored current-meter measurements at 10-m depth, based on which the classical Sverdrup circulation theory is evaluated. Calculations have shown that errors of wind stress calculation, AGC transport, and depth ranges of vertical integration cannot explain non-Sverdrup transport, which is mainly in the subtropical western ocean basins and equatorial currents near the Equator in each ocean basin (except the North Indian Ocean, where the circulation is dominated by monsoons). The identified non-Sverdrup transport is thereby robust and attributed to the joint effect of baroclinicity and relief of the bottom (JEBAR) and mesoscale eddy nonlinearity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007PhRvE..75b7301G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007PhRvE..75b7301G"><span id="translatedtitle"><span class="hlt">Absolute</span> instability of a viscous hollow jet</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gañán-Calvo, Alfonso M.</p> <p>2007-02-01</p> <p>An investigation of the spatiotemporal stability of hollow jets in unbounded coflowing liquids, using a general dispersion relation previously derived, shows them to be <span class="hlt">absolutely</span> unstable for all physical values of the Reynolds and Weber numbers. The roots of the symmetry breakdown with respect to the liquid jet case, and the validity of asymptotic models are here studied in detail. Asymptotic analyses for low and high Reynolds numbers are provided, showing that old and well-established limiting dispersion relations [J. W. S. Rayleigh, The Theory of Sound (Dover, New York, 1945); S. Chandrasekhar, Hydrodynamic and Hydromagnetic Stability (Dover, New York, 1961)] should be used with caution. In the creeping flow limit, the analysis shows that, if the hollow jet is filled with any finite density and viscosity fluid, a steady jet could be made arbitrarily small (compatible with the continuum hypothesis) if the coflowing liquid moves faster than a critical velocity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004SPIE.5252..305B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004SPIE.5252..305B"><span id="translatedtitle">Stitching interferometry: recent results and <span class="hlt">absolute</span> calibration</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bray, Michael</p> <p>2004-02-01</p> <p>Stitching Interferometry is a method of analysing large optical components using a standard "small" interferometer. This result is obtained by taking multiple overlapping images of the large component, and numerically "stitching" these sub-apertures together. We have already reported the industrial use our Stitching Interferometry systems (Previous SPIE symposia), but experimental results had been lacking because this technique is still new, and users needed to get accustomed to it before producing reliable measurements. We now have more results. We will report user comments and show new, unpublished results. We will discuss sources of error, and show how some of these can be reduced to arbitrarily small values. These will be discussed in some detail. We conclude with a few graphical examples of <span class="hlt">absolute</span> measurements performed by us.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMGP51B..07L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMGP51B..07L"><span id="translatedtitle">Swarm's <span class="hlt">Absolute</span> Scalar Magnetometer metrological performances</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Leger, J.; Fratter, I.; Bertrand, F.; Jager, T.; Morales, S.</p> <p>2012-12-01</p> <p>The <span class="hlt">Absolute</span> Scalar Magnetometer (ASM) has been developed for the ESA Earth Observation Swarm mission, planned for launch in November 2012. As its Overhauser magnetometers forerunners flown on Oersted and Champ satellites, it will deliver high resolution scalar measurements for the in-flight calibration of the Vector Field Magnetometer manufactured by the Danish Technical University. Latest results of the ground tests carried out to fully characterize all parameters that may affect its accuracy, both at instrument and satellite level, will be presented. In addition to its baseline function, the ASM can be operated either at a much higher sampling rate (burst mode at 250 Hz) or in a dual mode where it also delivers vector field measurements as a by-product. The calibration procedure and the relevant vector performances will be discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhRvA..92c2122C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhRvA..92c2122C"><span id="translatedtitle"><span class="hlt">Absolute</span> nonlocality via distributed computing without communication</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Czekaj, Ł.; Pawłowski, M.; Vértesi, T.; Grudka, A.; Horodecki, M.; Horodecki, R.</p> <p>2015-09-01</p> <p>Understanding the role that quantum entanglement plays as a resource in various information processing tasks is one of the crucial goals of quantum information theory. Here we propose an alternative perspective for studying quantum entanglement: distributed computation of functions without communication between nodes. To formalize this approach, we propose identity games. Surprisingly, despite no signaling, we obtain that nonlocal quantum strategies beat classical ones in terms of winning probability for identity games originating from certain bipartite and multipartite functions. Moreover we show that, for a majority of functions, access to general nonsignaling resources boosts success probability two times in comparison to classical ones for a number of large enough outputs. Because there are no constraints on the inputs and no processing of the outputs in the identity games, they detect very strong types of correlations: <span class="hlt">absolute</span> nonlocality.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..1812838N&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..1812838N&link_type=ABSTRACT"><span id="translatedtitle">Resilience in heterogeneous landscapes: The effect of <span class="hlt">topography</span> on resilience of carbon uptake in northern peatlands</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nijp, Jelmer; Temme, Arnaud; van Voorn, George; Teuling, Ryan; Soons, Merel; Kooistra, Lammert</p> <p>2016-04-01</p> <p>Northern peatlands contain and store enormous amounts of carbon, and therefore represent an important component of the carbon cycle of the earth. In these wetland ecosystems, the quality of the soil added to the soil surface is determined by the type of peat-forming plants, and affects the carbon accumulated in the peat soil later formed and overall ecosystem functioning. Peatland vegetation is frequently organized in alternating dry hummocks with wet hollows. Such patterned vegetation is associated with different soil carbon accumulation rates, and may develop due to various self-regulating processes originating from ecohydrological feedbacks. Simulation models have shown that vegetation patterning may promote the resilience of peatlands to environmental change (climate, land use), hence maintaining their function as carbon sink. Critically, the results of these model studies rely on the fundamental assumption that environmental conditions are spatially homogeneous. Yet, in real landscape settings, catchment <span class="hlt">topography</span> has a major impact on water flow and nutrient availability, and is expected to alter vegetation patterning. However, whether, where and how <span class="hlt">topography</span> affects vegetation patterning in peatlands and associated resilience of ecosystem service provision remains unknown. By combining field observations, remote sensing, and <span class="hlt">dynamic</span> simulation models (used both as 'sandbox' and 'resilience calculator' for given geomorphological settings), we determine how landscape <span class="hlt">topography</span> affects ecohydrological processes, vegetation patterning, and associated resilience to environmental change in northern peatlands.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014JGE....11a5003L&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014JGE....11a5003L&link_type=ABSTRACT"><span id="translatedtitle">Traveltime computation and imaging from rugged <span class="hlt">topography</span> in 3D TTI media</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, Shaoyong; Wang, Huazhong; Yang, Qinyong; Fang, Wubao</p> <p>2014-02-01</p> <p>Foothill areas with rugged <span class="hlt">topography</span> are of great potential for oil and gas seismic exploration, but subsurface imaging in these areas is very challenging. Seismic acquisition with larger offset and wider azimuth is necessary for seismic imaging in complex areas. However, the scale anisotropy in this case must be taken into account. To generalize the pre-stack depth migration (PSDM) to 3D transversely isotropic media with vertical symmetry axes (VTI) and tilted symmetry axes (TTI) from rugged <span class="hlt">topography</span>, a new <span class="hlt">dynamic</span> programming approach for the first-arrival traveltime computation method is proposed. The first-arrival time on every uniform mesh point is calculated based on Fermat's principle with simple calculus techniques and a systematic mapping scheme. In order to calculate the minimum traveltime, a set of nonlinear equations is solved on each mesh point, where the group velocity is determined by the group angle. Based on the new first-arrival time calculation method, the corresponding PSDM and migration velocity analysis workflow for 3D anisotropic media from rugged surface is developed. Numerical tests demonstrate that the proposed traveltime calculation method is effective in both VTI and TTI media. The migration results for 3D field data show that it is necessary to choose a smooth datum to remove the high wavenumber move-out components for PSDM with rugged <span class="hlt">topography</span> and take anisotropy into account to achieve better images.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016Geomo.260....4C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016Geomo.260....4C"><span id="translatedtitle">Reproducibility of UAV-based earth <span class="hlt">topography</span> reconstructions based on Structure-from-Motion algorithms</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Clapuyt, Francois; Vanacker, Veerle; Van Oost, Kristof</p> <p>2016-05-01</p> <p>Combination of UAV-based aerial pictures and Structure-from-Motion (SfM) algorithm provides an efficient, low-cost and rapid framework for remote sensing and monitoring of <span class="hlt">dynamic</span> natural environments. This methodology is particularly suitable for repeated topographic surveys in remote or poorly accessible areas. However, temporal analysis of landform <span class="hlt">topography</span> requires high accuracy of measurements and reproducibility of the methodology as differencing of digital surface models leads to error propagation. In order to assess the repeatability of the SfM technique, we surveyed a study area characterized by gentle <span class="hlt">topography</span> with an UAV platform equipped with a standard reflex camera, and varied the focal length of the camera and location of georeferencing targets between flights. Comparison of different SfM-derived <span class="hlt">topography</span> datasets shows that precision of measurements is in the order of centimetres for identical replications which highlights the excellent performance of the SfM workflow, all parameters being equal. The precision is one order of magnitude higher for 3D topographic reconstructions involving independent sets of ground control points, which results from the fact that the accuracy of the localisation of ground control points strongly propagates into final results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMNS43A1782L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMNS43A1782L"><span id="translatedtitle">Three-dimensional inversion of CSAMT data including <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lin, C.; Tan, H.; Tong, T.; Zeng, W.</p> <p>2013-12-01</p> <p>CSAMT is widely used in geothermal prospecting, mineral and petroleum exploration, environmental geophysics and geological engineering. However, few data are collected on the flat surface in the field CSAMT work. Most of CSAMT data are collected in the presence of strong <span class="hlt">topography</span> either at the source position or in the survey area. Large interpretation errors may occur in CSAMT surveys if field distortions caused by the surface <span class="hlt">topography</span> are not considered. Therefore, the CSAMT inversion should consider the topographic effect. In this work we develop a 3D inversion algorithm for inverting CSAMT data with <span class="hlt">topography</span> using conjugate gradient inversion method. In the 3D forward problem, the total electric and magnetic fields is separated into their primary and secondary components to calculate the response from the 3D model with irregular <span class="hlt">topography</span>. 3D rectangular grid with stair-stepped ground-air interface is used to approximate <span class="hlt">topography</span>. The primary electric and magnetic field can be calculated by one-dimensional modeling, using the altitude of the highest point of the <span class="hlt">topography</span> as the altitude of the flat surface. The secondary electric and magnetic field can be calculated using the staggered-grid finite difference method. Then, the apparent resistivity and phase response can be obtained by Cagniard equation. In the 3D inversion problem, conjugate gradient method is used to invert the CSAMT apparent resistivity and phase data including <span class="hlt">topography</span>. The background resistivity is a constant value and the anomalous resistivity is used as the inversion parameter. Only the anomalous resistivity under the surface <span class="hlt">topography</span> is updated in the inversion. Results from the synthetic tests show the validity and stability of the inversion algorithm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013IJMES..44..587S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013IJMES..44..587S"><span id="translatedtitle">A special application of <span class="hlt">absolute</span> value techniques in authentic problem solving</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stupel, Moshe</p> <p>2013-06-01</p> <p>There are at least five different equivalent definitions of the <span class="hlt">absolute</span> value concept. In instances where the task is an equation or inequality with only one or two <span class="hlt">absolute</span> value expressions, it is a worthy educational experience for learners to solve the task using each one of the definitions. On the other hand, if more than two <span class="hlt">absolute</span> value expressions are involved, the definition that is most helpful is the one involving solving by intervals and evaluating critical points. In point of fact, application of this technique is one reason that the topic of <span class="hlt">absolute</span> value is important in mathematics in general and in mathematics teaching in particular. We present here an authentic practical problem that is solved using <span class="hlt">absolute</span> values and the 'intervals' method, after which the solution is generalized with surprising results. This authentic problem also lends itself to investigation using educational technological tools such as GeoGebra <span class="hlt">dynamic</span> geometry software: mathematics teachers can allow their students to initially cope with the problem by working in an inductive environment in which they conduct virtual experiments until a solid conjecture has been reached, after which they should prove the conjecture deductively, using classic theoretical mathematical tools.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EGUGA..12.2402D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EGUGA..12.2402D"><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> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Doronzo, Domenico Maria; Valentine, Greg A.; Dellino, Pierfrancesco; de Tullio, Marco D.</p> <p>2010-05-01</p> <p>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 rate and the resulting deposits can record such effects in their sedimentological features. Here we show, by means of numerical simulations, how a dilute pyroclastic density current interacts with four different types of <span class="hlt">topographies</span>, namely: flat, one hill, one valley and two hills. The simulations are carried out by Ansys Fluent commercial software for applications in fluid <span class="hlt">dynamic</span> engineering. Our numerical scheme treats the very fine particles as being in full thermo-mechanical equilibrium with the volcanic gas (pseudo-fluid phase), and the trajectories of the coarser particles are tracked by means of the pseudo-fluid solution (Lagrangian particles). There is a two-way coupling between the pseudo-fluid phase and Lagrangian particles, which accounts for the reciprocal mechanical effects of the two phases. Numerical results are then used to analyze the local effects of <span class="hlt">topography</span> on the deposition of the Lagrangian particles, by monitoring with time and space the local changes at the boundary between the dilute pyroclastic density current and substrate. We use the sedimentation rate and grain-size distribution of the Lagrangian particles as proxies of the deposit features, and by these parameters we compare qualitatively the numerical results with the deposits of known eruptions: Mount St. Helens blast, Taupo ignimbrite and Vulcano surge deposits. The results reproduce qualitatively the natural deposits very well, and we conclude that Ansys Fluent software could be used in volcanology with success.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20040073468&hterms=Topography&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DTopography','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20040073468&hterms=Topography&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DTopography"><span id="translatedtitle">Evolution of <span class="hlt">Topography</span> in Glaciated Mountain Ranges</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Brocklehurst, Simon H.</p> <p>2002-01-01</p> <p>This thesis examines the response of alpine landscapes to the onset of glaciation. The basic approach is to compare fluvial and glacial laudscapes, since it is the change from the former to the latter that accompanies climatic cooling. This allows a detailed evaluation of hypotheses relating climate change to tectonic processes in glaciated mountain belts. Fieldwork was carried out in the eastern Sierra Nevada, California, and the Sangre de Cristo Range, Colorado, alongside digital elevation model analyses in the western US, the Southern Alps of New Zealand, and the Himalaya of northwestern Pakistan. hypothesis is overstated in its appeal to glacial erosion as a major source of relief production and subsequent peak uplift. Glaciers in the eastern Sierra Nevada and the western Sangre de Cristos have redistributed relief, but have produced only modest relief by enlarging drainage basins at the expense of low-relief <span class="hlt">topography</span>. Glaciers have lowered valley floors and ridgelines by similar amounts, limiting the amount of "missing mass' that can be generated, and causing a decrease in drainage basin relief. The principal response of glaciated landscapes to rapid rock uplift is the development of towering cirque headwalls. This represents considerable relief production, but is not caused by glacial erosion alone. Large valley glaciers can maintain their low gradient regardless of uplift rate, which supports the "glacial buzzsaw" hypothesis. However, the inability of glaciers to erode steep hillslopes as rapidly can cause mean elevations to rise. Cosmogenic isotope dating is used to show that (i) where plucking is active, the last major glaciation removed sufficient material to reset the cosmogenic clock; and (ii) former glacial valley floors now stranded near the crest of the Sierra Nevada are at varying stages of abandonment, suggesting a cycle of drainage reorganiszation and relief inversion due to glacial erosion similar to that observed in river networks. Glaciated</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20130009037','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20130009037"><span id="translatedtitle">Shuttle <span class="hlt">Topography</span> Data Inform Solar Power Analysis</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2013-01-01</p> <p>The next time you flip on a light switch, there s a chance that you could be benefitting from data originally acquired during the Space Shuttle Program. An effort spearheaded by Jet Propulsion Laboratory (JPL) and the National Geospatial-Intelligence Agency (NGA) in 2000 put together the first near-global elevation map of the Earth ever assembled, which has found use in everything from 3D terrain maps to models that inform solar power production. For the project, called the Shuttle Radar <span class="hlt">Topography</span> Mission (SRTM), engineers at JPL designed a 60-meter mast that was fitted onto Shuttle Endeavour. Once deployed in space, an antenna attached to the end of the mast worked in combination with another antenna on the shuttle to simultaneously collect data from two perspectives. Just as having two eyes makes depth perception possible, the SRTM data sets could be combined to form an accurate picture of the Earth s surface elevations, the first hight-detail, near-global elevation map ever assembled. What made SRTM unique was not just its surface mapping capabilities but the completeness of the data it acquired. Over the course of 11 days, the shuttle orbited the Earth nearly 180 times, covering everything between the 60deg north and 54deg south latitudes, or roughly 80 percent of the world s total landmass. Of that targeted land area, 95 percent was mapped at least twice, and 24 percent was mapped at least four times. Following several years of processing, NASA released the data to the public in partnership with NGA. Robert Crippen, a member of the SRTM science team, says that the data have proven useful in a variety of fields. "Satellites have produced vast amounts of remote sensing data, which over the years have been mostly two-dimensional. But the Earth s surface is three-dimensional. Detailed topographic data give us the means to visualize and analyze remote sensing data in their natural three-dimensional structure, facilitating a greater understanding of the features</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009GeoJI.178.1198C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009GeoJI.178.1198C"><span id="translatedtitle">An analysis of young ocean depth, gravity and global residual <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Crosby, A. G.; McKenzie, D.</p> <p>2009-09-01</p> <p>The variation of ocean depth with age in the absence of crustal thickening and <span class="hlt">dynamic</span> support places valuable constraints on the thermal and rheological properties of the lithosphere and asthenosphere. We have attempted to estimate this variation using a global data set of shiptracks, with particular emphasis on young ocean floor. In this respect, this paper extends a previous study published in this journal by the same authors, which concentrated on the older parts of the ocean basins. We find that, prior to 80 Ma, subsidence patterns are reasonably consistent, with gradients of 325 +/- 20 m Ma -1/2 and zero-age depths of 2600 +/- 200 m. There is a strong inverse correlation between zero-age depth and the gradient of depth with the square root of age which is unrelated to local variations in <span class="hlt">dynamic</span> support. Global depth-age trends to 160 Ma are not significantly different to those for the individual ocean basins. Within corridors of similar basement age, gravity-<span class="hlt">topography</span> correlations are consistently 30 +/- 5 mGal km-1. Simple isostatic theory and numerical modelling of mantle plumes suggests that, if the minimum depth of convection is defined by the base of the mechanical boundary layer, the admittance should be a function of plate age. The observation that it is not implies that the active convective upwelling beneath young lithosphere ceases at the same depth as it does beneath old oceanic plates. This result is consistent with geochemical modelling of melts near mid-ocean ridges. We have examined the relationship between residual <span class="hlt">topography</span> and gravity worldwide, and have found that good spatial correlations are restricted to the Atlantic, North Pacific and youngest Indian ocean basins. By contrast, residual <span class="hlt">topography</span> and gravity are poorly or negatively correlated in the South and young North Pacific Ocean and in the older Indian Ocean. Away from regions of thick crust and flexure, histograms of residual <span class="hlt">topography</span> and gravity have symmetric</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=233512&keyword=AIDS&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=65331050&CFTOKEN=81282874','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=233512&keyword=AIDS&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=65331050&CFTOKEN=81282874"><span id="translatedtitle">Predicting Maximum Lake Depth from Surrounding <span class="hlt">Topography</span></span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>Lake volume aids understanding of the physical and ecological <span class="hlt">dynamics</span> of lakes, yet is often not readily available. The data needed to calculate lake volume (i.e. bathymetry) are usually only collected on a lake by lake basis and are difficult to obtain across broad regions. ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/16256164','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/16256164"><span id="translatedtitle">Corneal <span class="hlt">topography</span>, refractive state, and accommodation in harbor seals (Phoca vitulina).</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hanke, Frederike D; Dehnhardt, Guido; Schaeffel, Frank; Hanke, Wolf</p> <p>2006-03-01</p> <p>Corneal <span class="hlt">topography</span> of a harbor seal measured with a Placido's disc shows a central flattened stripe in the vertical meridian. Together with a pupil that can form a vertical slit, the flat vertical meridian can minimize the optical effects caused by the transition from water to air. Using infrared (IR) photoretinoscopy, we analyzed the refractive state of harbor seals and revealed a high degree of myopia and astigmatism in air, but emmetropia or slight hyperopia with little astigmatism underwater. The brightness distribution in the pupils suggest the presence of a multifocal dioptric apparatus in air and underwater. We found a first indication for accommodation by <span class="hlt">dynamic</span> recordings underwater. PMID:16256164</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014AGUFM.T54B..05F&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014AGUFM.T54B..05F&link_type=ABSTRACT"><span id="translatedtitle">Evolution of the long-wavelength, subduction-driven <span class="hlt">topography</span> of South America since 150 Ma</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Flament, N. E.; Gurnis, M.; Williams, S.; Bower, D. J.; Seton, M.; Müller, D.</p> <p>2014-12-01</p> <p>Subduction to the west of South America spans 6000 km along strike and has been active for over 250 Myr. The influence of the history of subduction on the geodynamics of South America has been profound, driving mountain building and arc volcanism in the Andean Cordillera. Here, we investigate the long-wavelength changes in the <span class="hlt">topography</span> of South America associated with subduction and plate motion and their interplay with the lithospheric deformation associated with the opening of the South Atlantic. We pay particular attention to the topographic expression of flat-lying subduction zones. We develop time-dependent geodynamic models of mantle flow and lithosphere deformation to investigate the evolution of South American <span class="hlt">dynamic</span> and total <span class="hlt">topography</span> since the late Jurassic (150 Ma). Our models are semi-empirical because the computational cost of fully <span class="hlt">dynamic</span>, evolutionary models is still prohibitive. We impose the kinematics of global plate reconstructions with deforming continents in forward global mantle convection models with compositionally distinct crust and continental lithosphere embedded within the thermal lithosphere. The shallow thermal structure of subducting slabs is imposed, allowing us to investigate the evolution of <span class="hlt">dynamic</span> <span class="hlt">topography</span> around flat slab segments in time-dependent models. Multiple cases are used to investigate how the evolution of South American <span class="hlt">dynamic</span> <span class="hlt">topography</span> is influenced by mantle viscosity, the kinematics of the opening of the South Atlantic and alternative scenarios for recent and past flat-slab subduction. We predict that the migration of South America over sinking oceanic lithosphere resulted in continental tilt to the west until ~ 45 Ma, inverting to an eastward tilt thereafter. This first-order result is consistent with the reversal of the drainage of the Amazon River system. We investigate which scenarios of flat-slab subduction since the Eocene are compatible with geological constraints on the evolution of the Solimoes</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JGRB..121.3081W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JGRB..121.3081W"><span id="translatedtitle">Heat flux and <span class="hlt">topography</span> constraints on thermochemical structure below North China Craton regions and implications for evolution of cratonic lithosphere</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Yongming; Huang, Jinshui; Zhong, Shijie; Chen, Jiaming</p> <p>2016-04-01</p> <p>The eastern North China Craton (NCC) has undergone extensive reactivation during the Mesozoic and Cenozoic, while the western NCC has remained stable throughout its geological history. Geophysical and geochemical observations, including heat flux, surface <span class="hlt">topography</span>, crustal and lithospheric thicknesses, and volcanism, show significant contrast between the eastern and western NCC. These observations provide constraints on thermochemical structure and reactivation process of the eastern NCC, thus helping understand the <span class="hlt">dynamic</span> evolution of cratonic lithosphere. In this study, we determined the residual <span class="hlt">topography</span> for the NCC region by removing crustal contribution to the <span class="hlt">topography</span>. We found that the residual <span class="hlt">topography</span> of the eastern NCC region is generally 0.3-0.9 km higher than the western NCC. We computed a large number of two-dimension thermochemical convection models for gravitational instability of cratonic lithosphere and quantified surface heat flux and <span class="hlt">topography</span> contrasts between stable and destabilized parts of cratonic lithosphere. These models consider different chemical buoyancy (i.e., buoyancy number B) and viscosity for the cratonic lithosphere. Our models suggest that to explain the difference in heat flux (25-30 mW/m2) and residual <span class="hlt">topography</span> (0.3-0.9 km) between the eastern and western NCC regions, the buoyancy number B is required to be ~0.3-0.4. This range of B implies that as much as 50% of the original cratonic lithospheric material remains in the present-day eastern NCC lithosphere and its underlying shallow mantle and that the new lithosphere in the eastern NCC may be a mixture of the relics of old craton materials and the normal mantle.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013AGUFM.T41B2579S&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013AGUFM.T41B2579S&link_type=ABSTRACT"><span id="translatedtitle">Impact of the rheological layering of the lithosphere on the <span class="hlt">topography</span> generated by sublithospheric density anomalies: Insights from analog modeling</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sembroni, A.; Globig, J.; Rozel, A.; Faccenna, C.; Funiciello, F.; Fernandez, M.</p> <p>2013-12-01</p> <p>Density anomalies located beneath the lithosphere are thought to generate <span class="hlt">dynamic</span> <span class="hlt">topography</span> at the surface of the Earth. Tomographic models are often used to infer the later variations of the density field in the mantle. Surface <span class="hlt">topography</span> can then be computed using analytical solutions or numerical simulations of mantle convection. It has been shown that the viscosity profile of the upper mantle has a strong influence on the magnitude and spectral signature of surface <span class="hlt">topography</span> and uplift rate. Here we present results from analogue modeling of the interaction between a rising ball-shaped density anomaly and the lithosphere in an isoviscous, isothermal Newtonian mantle system. Preliminary data show that surface <span class="hlt">topography</span> is strongly influenced not only by mantle viscosity but also by density and viscosity profiles of the lithosphere. Our apparatus consists of a plexiglass square box (40x40x50 cm3) filled with glucose syrup. From the bottom a silicon ball was free to rise up until impinging a silicon plate floating on top of the syrup, mimicking the lithosphere. In order to investigate the role of lithospheric thickness and layered continental crust on stress partitioning, maximum <span class="hlt">dynamic</span> <span class="hlt">topography</span>, uplift rate and signal wavelength, two different configurations were tested: homogeneous lithosphere and stratified lithosphere including a low-viscosity lower crust. The topographic evolution of the surface was tracked using a laser scanning the top of the apparatus. The rise of the density anomaly was recorded by a side camera. We observe that a thick and then more resistant lithosphere makes up to 2 times lower and laterally wider topographic signatures. Layered lithospheres including a decoupling lower crust decrease the equilibrium <span class="hlt">topography</span> and its lateral extend by ~30% to 40%. Most importantly, the uplift rate is strongly affected by the choice of lithosphere model. Both lithosphere width and the presence of a decoupling lower crust may modify the uplift</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2005JaJAP..44.6304Y&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2005JaJAP..44.6304Y&link_type=ABSTRACT"><span id="translatedtitle">Observation on Effect of Optical Stimulation to Human Using Optical <span class="hlt">Topography</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yanai, Hiro-Fumi; Yorimoto, Akiyoshi; Kubota, Toshio; Fujii, Kan-ichi; Kawaguchi, Fumio; Yamamoto, Etsuji; Ichikawa, Noriyoshi; Koshino, Yoshihumi</p> <p>2005-08-01</p> <p>We have observed the time course features of cerebral response while a subject is performing the visual tracking task or visual tracking plus finger tapping task using Optiocal <span class="hlt">Topography</span> (OT). The distribution maps of both oxygenated and deoxygenated hemoglobins are demonstrated in contrast with the time course diagram. The response of the cerebrum differs, depending on whether the optical stimulation is static or <span class="hlt">dynamic</span>, even when the overall nature of the pattern and intensity of the stimulation is the same. The cerebral response to a <span class="hlt">dynamic</span> optical stimulation is very rapid and clear, and greater in magnitude than that to static optical stimulation, but it is suppressed when an auxiliary finger tapping task is also performed. From these results, it was confirmed that OT is sensitive to both static and <span class="hlt">dynamic</span> optical stimulations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.1146S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.1146S"><span id="translatedtitle">Combined <span class="hlt">absolute</span> and relative gravity measurement for microgravity monitoring in Aso volcanic field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sofyan, Yayan; Nishijima, Jun; Yoshikawa, Shin; Fujimitsu, Yasuhiro; Kagiyama, Tsuneomi; Fukuda, Yoichi</p> <p>2014-05-01</p> <p><span class="hlt">Absolute</span> measurement with a portable A10-017 <span class="hlt">absolute</span> gravimeter at some benchmarks in the Aso volcanic field are valuable for reducing uncertainties of regional gravity variations and will be useful for delineating the long term trends of gravity changes. A10 <span class="hlt">absolute</span> gravimeter is a new generation of portable <span class="hlt">absolute</span> instrument and has accuracy 10 microGal. To further the development of a high precision gravity data, we also conducted measurement using two relative gravimeter (Scintrex CG-5 [549] and LaCoste type G-1016) to be combined with an A10 <span class="hlt">absolute</span> gravimeter. The using <span class="hlt">absolute</span> gravimeter along with relative gravimeter can reduce drift correction factor and improve the result of gravity change data in microgravity monitoring. Microgravity monitoring is a valued tool for mapping the redistribution of subsurface mass and for assessing changes in the fluid as a <span class="hlt">dynamic</span> process in volcanic field. Gravity changes enable the characterization of subsurface processes: i.e., the mass of the intrusion or hydrothermal flow. A key assumption behind gravity monitoring is that changes in earth's gravity reflect mass-transport processes at depth [1]. The <span class="hlt">absolute</span> gravity network was installed at seven benchmarks using on May 2010, which re-occupied in October 2010, and June 2011. The relative gravity measurements were performed at 28 benchmarks in one month before the eruption on May 2011 and then followed by series of gravity monitoring after the eruption in every three to five months. Gravity measurements covered the area more than 60 km2 in the west side of Aso caldera. Some gravity benchmarks were measured using both <span class="hlt">absolute</span> and relative gravimeter and is used as the reference benchmarks. In longer time period, the combined gravity method will improve the result of gravity change data for monitoring in the Aso volcanic field. As a result, the gravity changes detected the hydrothermal flow in the subsurface which has a correlation to water level fluctuation in the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014APS..MARG11003G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014APS..MARG11003G"><span id="translatedtitle">Quantifying actin wave modulation on periodic <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Guven, Can; Driscoll, Meghan; Sun, Xiaoyu; Parker, Joshua; Fourkas, John; Carlsson, Anders; Losert, Wolfgang</p> <p>2014-03-01</p> <p>Actin is the essential builder of the cell cytoskeleton, whose <span class="hlt">dynamics</span> are responsible for generating the necessary forces for the formation of protrusions. By exposing amoeboid cells to periodic topographical cues, we show that actin can be directionally guided via inducing preferential polymerization waves. To quantify the <span class="hlt">dynamics</span> of these actin waves and their interaction with the substrate, we modify a technique from computer vision called ``optical flow.'' We obtain vectors that represent the apparent actin flow and cluster these vectors to obtain patches of newly polymerized actin, which represent actin waves. Using this technique, we compare experimental results, including speed distribution of waves and distance from the wave centroid to the closest ridge, with actin polymerization simulations. We hypothesize the modulation of the activity of nucleation promotion factors on ridges (elevated regions of the surface) as a potential mechanism for the wave-substrate coupling. Funded by NIH grant R01GM085574.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFMIN33A1034C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFMIN33A1034C"><span id="translatedtitle">Visualization of High-Resolution LiDAR <span class="hlt">Topography</span> in Google Earth</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Crosby, C. J.; Nandigam, V.; Arrowsmith, R.; Blair, J. L.</p> <p>2009-12-01</p> <p>. This method provides seamlessly access to hillshaded imagery for both bare earth and first return terrain models with various angles of illumination. Seamless access to LiDAR-derived imagery in Google Earth has proven to be the most popular product available in the Open<span class="hlt">Topography</span> Portal. The hillshade KMZ files have been downloaded over 3000 times by users ranging from earthquake scientists to K-12 educators who wish to introduce cutting edge real world data into their earth science lessons. Open<span class="hlt">Topography</span> also provides <span class="hlt">dynamically</span> generated KMZ visualizations of LiDAR data products produced when users choose to use the Open<span class="hlt">Topography</span> point cloud access and processing system. These Google Earth compatible products allow users to quickly visualize the custom terrain products they have generated without the burden of loading the data into a GIS environment. For users who have installed the Google Earth browser plug-in, these visualizations can be launched directly from the Open<span class="hlt">Topography</span> results page and viewed directly in the browser.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1001683','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1001683"><span id="translatedtitle">Gyrokinetic Statistical <span class="hlt">Absolute</span> Equilibrium and Turbulence</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Jian-Zhou Zhu and Gregory W. Hammett</p> <p>2011-01-10</p> <p>A paradigm based on the <span class="hlt">absolute</span> equilibrium of Galerkin-truncated inviscid systems to aid in understanding turbulence [T.-D. Lee, "On some statistical properties of hydrodynamical and magnetohydrodynamical fields," Q. Appl. Math. 10, 69 (1952)] is taken to study gyrokinetic plasma turbulence: A finite set of Fourier modes of the collisionless gyrokinetic equations are kept and the statistical equilibria are calculated; possible implications for plasma turbulence in various situations are discussed. For the case of two spatial and one velocity dimension, in the calculation with discretization also of velocity v with N grid points (where N + 1 quantities are conserved, corresponding to an energy invariant and N entropy-related invariants), the negative temperature states, corresponding to the condensation of the generalized energy into the lowest modes, are found. This indicates a generic feature of inverse energy cascade. Comparisons are made with some classical results, such as those of Charney-Hasegawa-Mima in the cold-ion limit. There is a universal shape for statistical equilibrium of gyrokinetics in three spatial and two velocity dimensions with just one conserved quantity. Possible physical relevance to turbulence, such as ITG zonal flows, and to a critical balance hypothesis are also discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003APS..MARB25007Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003APS..MARB25007Z"><span id="translatedtitle"><span class="hlt">Absolute</span> surface energy for zincblende semiconductors</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, S. B.; Wei, Su-Huai</p> <p>2003-03-01</p> <p>Recent advance in nanosciences requires the determination of surface (or facet) energy of semiconductors, which is often difficult due to the polar nature of some of the most important surfaces such as the (111)A/(111)B surfaces. Several approaches have been developed in the past [1-3] to deal with the problem but an unambiguous division of the polar surface energies is yet to come [2]. Here we show that an accurate division is indeed possible for the zincblende semiconductors and will present the results for GaAs, ZnSe, and CuInSe2 [4], respectively. A general trend emerges, relating the <span class="hlt">absolute</span> surface energy to the ionicity of the bulk materials. [1] N. Chetty and R. M. Martin, Phys. Rev. B 45, 6074 (1992). [2] N. Moll, et al., Phys. Rev. B 54, 8844 (1996). [3] S. Mankefors, Phys. Rev. B 59, 13151 (1999). [4] S. B. Zhang and S.-H. Wei, Phys. Rev. B 65, 081402 (2002).</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_24 --> <div id="page_25" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="481"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20160006426','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20160006426"><span id="translatedtitle">Climate <span class="hlt">Absolute</span> Radiance and Refractivity Observatory (CLARREO)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Leckey, John P.</p> <p>2015-01-01</p> <p>The Climate <span class="hlt">Absolute</span> Radiance and Refractivity Observatory (CLARREO) is a mission, led and developed by NASA, that will measure a variety of climate variables with an unprecedented accuracy to quantify and attribute climate change. CLARREO consists of three separate instruments: an infrared (IR) spectrometer, a reflected solar (RS) spectrometer, and a radio occultation (RO) instrument. The mission will contain orbiting radiometers with sufficient accuracy, including on orbit verification, to calibrate other space-based instrumentation, increasing their respective accuracy by as much as an order of magnitude. The IR spectrometer is a Fourier Transform spectrometer (FTS) working in the 5 to 50 microns wavelength region with a goal of 0.1 K (k = 3) accuracy. The FTS will achieve this accuracy using phase change cells to verify thermistor accuracy and heated halos to verify blackbody emissivity, both on orbit. The RS spectrometer will measure the reflectance of the atmosphere in the 0.32 to 2.3 microns wavelength region with an accuracy of 0.3% (k = 2). The status of the instrumentation packages and potential mission options will be presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JPhCS.381a2078W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JPhCS.381a2078W"><span id="translatedtitle"><span class="hlt">Absolute</span> decay width measurements in 16O</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wheldon, C.; Ashwood, N. I.; Barr, M.; Curtis, N.; Freer, M.; Kokalova, Tz; Malcolm, J. D.; Spencer, S. J.; Ziman, V. A.; Faestermann, Th; Krücken, R.; Wirth, H.-F.; Hertenberger, R.; Lutter, R.; Bergmaier, A.</p> <p>2012-09-01</p> <p>The reaction 126C(63Li, d)168O* at a 6Li bombarding energy of 42 MeV has been used to populate excited states in 16O. The deuteron ejectiles were measured using the high-resolution Munich Q3D spectrograph. A large-acceptance silicon-strip detector array was used to register the recoil and break-up products. This complete kinematic set-up has enabled <span class="hlt">absolute</span> α-decay widths to be measured with high-resolution in the 13.9 to 15.9 MeV excitation energy regime in 16O; many for the first time. This energy region spans the 14.4 MeV four-α breakup threshold. Monte-Carlo simulations of the detector geometry and break-up processes yield detection efficiencies for the two dominant decay modes of 40% and 37% for the α+12C(g.s.) and a+12C(2+1) break-up channels respectively.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PhRvA..90a3825D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PhRvA..90a3825D"><span id="translatedtitle"><span class="hlt">Absolute</span> calibration of forces in optical tweezers</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dutra, R. S.; Viana, N. B.; Maia Neto, P. A.; Nussenzveig, H. M.</p> <p>2014-07-01</p> <p>Optical tweezers are highly versatile laser traps for neutral microparticles, with fundamental applications in physics and in single molecule cell biology. Force measurements are performed by converting the stiffness response to displacement of trapped transparent microspheres, employed as force transducers. Usually, calibration is indirect, by comparison with fluid drag forces. This can lead to discrepancies by sizable factors. Progress achieved in a program aiming at <span class="hlt">absolute</span> calibration, conducted over the past 15 years, is briefly reviewed. Here we overcome its last major obstacle, a theoretical overestimation of the peak stiffness, within the most employed range for applications, and we perform experimental validation. The discrepancy is traced to the effect of primary aberrations of the optical system, which are now included in the theory. All required experimental parameters are readily accessible. Astigmatism, the dominant effect, is measured by analyzing reflected images of the focused laser spot, adapting frequently employed video microscopy techniques. Combined with interface spherical aberration, it reveals a previously unknown window of instability for trapping. Comparison with experimental data leads to an overall agreement within error bars, with no fitting, for a broad range of microsphere radii, from the Rayleigh regime to the ray optics one, for different polarizations and trapping heights, including all commonly employed parameter domains. Besides signaling full first-principles theoretical understanding of optical tweezers operation, the results may lead to improved instrument design and control over experiments, as well as to an extended domain of applicability, allowing reliable force measurements, in principle, from femtonewtons to nanonewtons.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005A%26A...436..967W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005A%26A...436..967W"><span id="translatedtitle"><span class="hlt">Absolute</span> spectrophotometry of northern compact planetary nebulae</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wright, S. A.; Corradi, R. L. M.; Perinotto, M.</p> <p>2005-06-01</p> <p>We present medium-dispersion spectra and narrowband images of six northern compact planetary nebulae (PNe): BoBn 1, DdDm 1, IC 5117, M 1-5, M 1-71, and NGC 6833. From broad-slit spectra, total <span class="hlt">absolute</span> fluxes and equivalent widths were measured for all observable emission lines. High signal-to-noise emission line fluxes of Hα, Hβ, [Oiii], [Nii], and HeI may serve as emission line flux standards for northern hemisphere observers. From narrow-slit spectra, we derive systemic radial velocities. For four PNe, available emission line fluxes were measured with sufficient signal-to-noise to probe the physical properties of their electron densities, temperatures, and chemical abundances. BoBn 1 and DdDm 1, both type IV PNe, have an Hβ flux over three sigma away from previous measurements. We report the first abundance measurements of M 1-71. NGC 6833 measured radial velocity and galactic coordinates suggest that it is associated with the outer arm or possibly the galactic halo, and its low abundance ([O/H]=1.3× 10-4) may be indicative of low metallicity within that region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1227359','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1227359"><span id="translatedtitle"><span class="hlt">Absolute</span> nuclear material assay using count distribution (LAMBDA) space</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Prasad, Mano K.; Snyderman, Neal J.; Rowland, Mark S.</p> <p>2015-12-01</p> <p>A method of <span class="hlt">absolute</span> nuclear material assay of an unknown source comprising counting neutrons from the unknown source and providing an <span class="hlt">absolute</span> nuclear material assay utilizing a model to optimally compare to the measured count distributions. In one embodiment, the step of providing an <span class="hlt">absolute</span> nuclear material assay comprises utilizing a random sampling of analytically computed fission chain distributions to generate a continuous time-evolving sequence of event-counts by spreading the fission chain distribution in time.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1055713','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1055713"><span id="translatedtitle"><span class="hlt">Absolute</span> nuclear material assay using count distribution (LAMBDA) space</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Prasad, Manoj K.; Snyderman, Neal J.; Rowland, Mark S.</p> <p>2012-06-05</p> <p>A method of <span class="hlt">absolute</span> nuclear material assay of an unknown source comprising counting neutrons from the unknown source and providing an <span class="hlt">absolute</span> nuclear material assay utilizing a model to optimally compare to the measured count distributions. In one embodiment, the step of providing an <span class="hlt">absolute</span> nuclear material assay comprises utilizing a random sampling of analytically computed fission chain distributions to generate a continuous time-evolving sequence of event-counts by spreading the fission chain distribution in time.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120009897','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120009897"><span id="translatedtitle">Gravity, <span class="hlt">Topography</span>, and Magnetic Field of Mercury from Messenger</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Neumann, Gregory A.; Solomon, Sean C.; Zuber, Maria T.; Phillips, Roger J.; Barnouin, Olivier; Ernst, Carolyn; Goosens, Sander; Hauck, Steven A., II; Head, James W., III; Johnson, Catherine L.; Lemoine, Frank G.; Margot, Jean-Luc; McNutt, Ralph; Mazarico, Erwan M.; Oberst, Jurgen; Peale, Stanley J.; Perry, Mark; Purucker, Michael E.; Rowlands, David D.; Torrence, Mark H.</p> <p>2012-01-01</p> <p>On 18 March 2011, the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft was inserted into a 12-hour, near-polar orbit around Mercury, with an initial periapsis altitude of 200 km, initial periapse latitude of 60 deg N, and apoapsis at approximately 15,200 km altitude in the southern hemisphere. This orbit has permitted the mapping of regional gravitational structure in the northern hemisphere, and laser altimetry from the MESSENGER spacecraft has yielded a geodetically controlled elevation model for the same hemisphere. The shape of a planet combined with gravity provides fundamental information regarding its internal structure and geologic and thermal evolution. Elevations in the northern hemisphere exhibit a unimodal distribution with a <span class="hlt">dynamic</span> range of 9.63 km, less than that of the Moon (19.9 km), but consistent with Mercury's higher surface gravitational acceleration. After one Earth-year in orbit, refined models of gravity and <span class="hlt">topography</span> have revealed several large positive gravity anomalies that coincide with major impact basins. These candidate mascons have anomalies that exceed 100 mGal and indicate substantial crustal thinning and superisostatic uplift of underlying mantle. An additional uncompensated 1000-km-diameter gravity and topographic high at 68 deg N, 33 deg E lies within Mercury's northern volcanic plains. Mercury's northern hemisphere crust is generally thicker at low latitudes than in the polar region. The low-degree gravity field, combined with planetary spin parameters, yields the moment of inertia C/MR2 = 0.353 +/- 0.017, where M=3.30 x 10(exp 23) kg and R=2440 km are Mercury's mass and radius, and a ratio of the moment of inertia of Mercury's solid outer shell to that of the planet of Cm/C = 0.452 +/- 0.035. One proposed model for Mercury's radial density distribution consistent with these results includes silicate crust and mantle layers overlying a dense solid (possibly Fe-S) layer, a liquid Fe</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMDI11A1831D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMDI11A1831D"><span id="translatedtitle">Evidence for a gradual decrease of geoid to <span class="hlt">topography</span> ratio along the Hawaiian island chain</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Diament, M.; Cadio, C.; Panet, I.</p> <p>2010-12-01</p> <p>It is well known that the seafloor around the Hawaiian island chain is unusually shallow. Two main hypotheses for the origin of this swell are generally considered: the thermal lithospheric thinning and the <span class="hlt">dynamical</span> support by a convective ascending plume. A major goal of these models is to quantitatively explain two important characteristics of the Hawaiian swell: its <span class="hlt">topography</span> and the corresponding geoid anomaly. In simple models of isostatic compensation, the geoid-to-<span class="hlt">topography</span> ratio (GTR) is linearly related to the apparent compensation depth; therefore it is often considered as a fundamental parameter to assess the swell support. This is why the <span class="hlt">topography</span> and geoid anomalies over the Hawaiian swell have been the subject of many investigations. The observed GTR has been reported to lie between 4 and 5 m/km. The corresponding apparent compensation depth is about 45 km, which is shallower than predicted by the <span class="hlt">dynamic</span> support model. However, analysis of the data processing methods shows that the applied bandpass filters to retain only characteristic wavelengths of the swell <span class="hlt">topography</span> and geoid, cannot completely remove the signal due to the volcanic edifice and lithospheric flexure, and this biases the resulting GTR. Consequently, we propose a new method based on continuous wavelet transform, which allows us to obtain the GTR in the space and in the frequency domains. We show that the GTR varies along the swell, from 8 m/km on Big Island to 3-4 m/km 2000 km to the northwest, for the scales ranging between 1100 and 1600 km. This reflects a decay of the apparent compensation depth moving along the islands chain. Our results are consistent with the recent seismic study from Li et al. [Nature 427 (2004) 827-829], where the authors evidence that the lithosphere gradually thins along the islands chain to about 50-60 km below Kauai. These results together converge to a hybrid model for the origin of the Hawaiian swell: the swell as a whole is supported <span class="hlt">dynamically</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27248566','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27248566"><span id="translatedtitle">The <span class="hlt">absolute</span> disparity anomaly and the mechanism of relative disparities.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chopin, Adrien; Levi, Dennis; Knill, David; Bavelier, Daphne</p> <p>2016-06-01</p> <p>There has been a long-standing debate about the mechanisms underlying the perception of stereoscopic depth and the computation of the relative disparities that it relies on. Relative disparities between visual objects could be computed in two ways: (a) using the difference in the object's <span class="hlt">absolute</span> disparities (Hypothesis 1) or (b) using relative disparities based on the differences in the monocular separations between objects (Hypothesis 2). To differentiate between these hypotheses, we measured stereoscopic discrimination thresholds for lines with different <span class="hlt">absolute</span> and relative disparities. Participants were asked to judge the depth of two lines presented at the same distance from the fixation plane (<span class="hlt">absolute</span> disparity) or the depth between two lines presented at different distances (relative disparity). We used a single stimulus method involving a unique memory component for both conditions, and no extraneous references were available. We also measured vergence noise using Nonius lines. Stereo thresholds were substantially worse for <span class="hlt">absolute</span> disparities than for relative disparities, and the difference could not be explained by vergence noise. We attribute this difference to an absence of conscious readout of <span class="hlt">absolute</span> disparities, termed the <span class="hlt">absolute</span> disparity anomaly. We further show that the pattern of correlations between vergence noise and <span class="hlt">absolute</span> and relative disparity acuities can be explained jointly by the existence of the <span class="hlt">absolute</span> disparity anomaly and by the assumption that relative disparity information is computed from <span class="hlt">absolute</span> disparities (Hypothesis 1). PMID:27248566</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4898198','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4898198"><span id="translatedtitle">The <span class="hlt">absolute</span> disparity anomaly and the mechanism of relative disparities</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Chopin, Adrien; Levi, Dennis; Knill, David; Bavelier, Daphne</p> <p>2016-01-01</p> <p>There has been a long-standing debate about the mechanisms underlying the perception of stereoscopic depth and the computation of the relative disparities that it relies on. Relative disparities between visual objects could be computed in two ways: (a) using the difference in the object's <span class="hlt">absolute</span> disparities (Hypothesis 1) or (b) using relative disparities based on the differences in the monocular separations between objects (Hypothesis 2). To differentiate between these hypotheses, we measured stereoscopic discrimination thresholds for lines with different <span class="hlt">absolute</span> and relative disparities. Participants were asked to judge the depth of two lines presented at the same distance from the fixation plane (<span class="hlt">absolute</span> disparity) or the depth between two lines presented at different distances (relative disparity). We used a single stimulus method involving a unique memory component for both conditions, and no extraneous references were available. We also measured vergence noise using Nonius lines. Stereo thresholds were substantially worse for <span class="hlt">absolute</span> disparities than for relative disparities, and the difference could not be explained by vergence noise. We attribute this difference to an absence of conscious readout of <span class="hlt">absolute</span> disparities, termed the <span class="hlt">absolute</span> disparity anomaly. We further show that the pattern of correlations between vergence noise and <span class="hlt">absolute</span> and relative disparity acuities can be explained jointly by the existence of the <span class="hlt">absolute</span> disparity anomaly and by the assumption that relative disparity information is computed from <span class="hlt">absolute</span> disparities (Hypothesis 1). PMID:27248566</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APS..DFDL29002Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..DFDL29002Z"><span id="translatedtitle">Internal wave generation by tidal flow over random <span class="hlt">topography</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhao, Jiajun; Zhang, Likun; Swinney, Harry</p> <p>2015-11-01</p> <p>The irregularity of oceanic <span class="hlt">topography</span> plays a critical role in determining the power in internal waves generated by tidal flow over the seafloor. We conduct numerical simulations (for a fluid with a constant buoyancy frequency) for different synthetic random <span class="hlt">topographies</span>. For <span class="hlt">topography</span> with small rms height Hrms and small slopes the simulations yield a quadratic dependence of the power on Hrms, in accord with linear theory. However, for tall <span class="hlt">topography</span> with steep slopes the internal wave power is found to vary linearly with Hrms. The transition from quadratic to linear scaling of the radiated internal wave power on Hrms occurs when the ``valley slope'' exceeds the internal wave slope. (The valley slope, to be defined in this talk, characterizes the maximum slope of <span class="hlt">topography</span> between adjacent peaks.) The simulations also reveal that the radiated power saturates with increasing topographic resolution, as conjectured in previous studies. The present results should be helpful in improving estimates of the total internal wave power generated by the world's oceans.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3233243','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3233243"><span id="translatedtitle">Corneal <span class="hlt">topography</span> from spectral optical coherence tomography (sOCT)</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ortiz, Sergio; Siedlecki, Damian; Pérez-Merino, Pablo; Chia, Noelia; de Castro, Alberto; Szkulmowski, Maciej; Wojtkowski, Maciej; Marcos, Susana</p> <p>2011-01-01</p> <p>We present a method to obtain accurate corneal <span class="hlt">topography</span> 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 <span class="hlt">topography</span> measurements on spherical and aspheric lenses, as well as on 10 human corneas in vivo. Results of sOCT surface <span class="hlt">topography</span> (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 <span class="hlt">topography</span> 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 <span class="hlt">topographies</span> without fan distortion correction and the rest of the measurements. PMID:22162814</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/20723035','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/20723035"><span id="translatedtitle">A novel conical intersection <span class="hlt">topography</span> and its consequences: The 1, 2 {sup 2}A conical intersection seam of the vinoxy radical</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Young, R. Andrew Jr.; Yarkony, David R.</p> <p>2005-08-22</p> <p>A region of the 1, 2 {sup 2}A seam of accidental conical intersections in the vinoxy radical exhibits a novel <span class="hlt">topography</span> which has important consequences for both upper-state to lower-state and lower-state to upper-state nonadiabatic transitions. The impact of this <span class="hlt">topography</span> on these nonadiabatic transitions is described. We also considered the possibility that this conical intersection seam provides a <span class="hlt">dynamical</span> bottleneck to the photodissociation of vinoxy to H+ketene by facilitating nonadiabatic recrossing. Our analysis of the conical <span class="hlt">topographies</span> and the proximity of the conical intersections to the transition state for dissociation to H+ketene does not support nonadiabatic recrossing as an effective <span class="hlt">dynamical</span> bottleneck blocking the H+ketene channel.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.P22B..05D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.P22B..05D"><span id="translatedtitle">Modeling Floods in Athabasca Valles, Mars, Using CTX Stereo <span class="hlt">Topography</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dundas, C. M.; Keszthelyi, L. P.; Denlinger, R. P.; Thomas, O. H.; Galuszka, D.; Hare, T. M.; Kirk, R. L.; Howington-Kraus, E.; Rosiek, M.</p> <p>2012-12-01</p> <p>Among the most remarkable landforms on Mars are the outflow channels, which suggest the occurrence of catastrophic water floods in the past. Athabasca Valles has long been thought to be the youngest of these channels [1-2], although it has recently become clear that the young crater age applies to a coating lava flow [3]. Simulations with a 2.5-dimensional flood model have provided insight into the details of flood <span class="hlt">dynamics</span> but have also demonstrated that the Digital Elevation Model (DEM) from the Mars Orbiter Laser Altimeter (MOLA) Mission Experiment Gridded Data Records includes significant artifacts at this latitude at the scales relevant for flood modeling [4]. In order to obtain improved <span class="hlt">topography</span>, we processed stereo images from the Context Camera (CTX) of the Mars Reconnaissance Orbiter (MRO) using methods developed for producing topographic models of the Moon with images from the Lunar Reconnaissance Orbiter Camera, a derivative of the CTX camera. Some work on flood modeling with CTX stereo has been published by [5], but we will present several advances, including corrections to the published CTX optical distortion model and improved methods to combine the stereo and MOLA data. The limitations of current methods are the accuracy of control to MOLA and the level of error introduced when the MRO spacecraft is not in a high-stability mode during stereo imaging, leading to jitter impacting the derived <span class="hlt">topography</span>. Construction of a mosaic of multiple stereo pairs, controlled to MOLA, allows us to consider flow through the cluster of streamlined islands in the upper part of the channel [6], including what is suggested to be the best example of flood-formed subaqueous dunes on Mars [7]. We will present results from running a flood model [4, 8] through the high-resolution (100 m/post) DEM covering the streamlined islands and subaqueous dunes, using results from a lower-resolution model as a guide to the inflow. By considering a range of flow levels below estimated</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1984EOSTr..65..706R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1984EOSTr..65..706R"><span id="translatedtitle"><span class="hlt">Dynamics</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ransom, Barbara</p> <p>1984-04-01</p> <p>“<span class="hlt">Dynamics</span>!” she said, as she buried her head deep in a book on tectonics. “Must be the key to explain what we see the ignorance of which seems to be chronic.”Convection below, then density flow and phase changes are not withstanding; Thermal gradient change and compositional range are things our minds should be commanding.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120012063','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120012063"><span id="translatedtitle">Orion <span class="hlt">Absolute</span> Navigation System Progress and Challenge</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Holt, Greg N.; D'Souza, Christopher</p> <p>2012-01-01</p> <p>The <span class="hlt">absolute</span> navigation design of NASA's Orion vehicle is described. It has undergone several iterations and modifications since its inception, and continues as a work-in-progress. This paper seeks to benchmark the current state of the design and some of the rationale and analysis behind it. There are specific challenges to address when preparing a timely and effective design for the Exploration Flight Test (EFT-1), while still looking ahead and providing software extensibility for future exploration missions. The primary onboard measurements in a Near-Earth or Mid-Earth environment consist of GPS pseudo-range and delta-range, but for future explorations missions the use of star-tracker and optical navigation sources need to be considered. Discussions are presented for state size and composition, processing techniques, and consider states. A presentation is given for the processing technique using the computationally stable and robust UDU formulation with an Agee-Turner Rank-One update. This allows for computational savings when dealing with many parameters which are modeled as slowly varying Gauss-Markov processes. Preliminary analysis shows up to a 50% reduction in computation versus a more traditional formulation. Several state elements are discussed and evaluated, including position, velocity, attitude, clock bias/drift, and GPS measurement biases in addition to bias, scale factor, misalignment, and non-orthogonalities of the accelerometers and gyroscopes. Another consideration is the initialization of the EKF in various scenarios. Scenarios such as single-event upset, ground command, and cold start are discussed as are strategies for whole and partial state updates as well as covariance considerations. Strategies are given for dealing with latent measurements and high-rate propagation using multi-rate architecture. The details of the rate groups and the data ow between the elements is discussed and evaluated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140001056','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140001056"><span id="translatedtitle">Evaluation of the <span class="hlt">Absolute</span> Regional Temperature Potential</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Shindell, D. T.</p> <p>2012-01-01</p> <p>The <span class="hlt">Absolute</span> Regional Temperature Potential (ARTP) is one of the few climate metrics that provides estimates of impacts at a sub-global scale. The ARTP presented here gives the time-dependent temperature response in four latitude bands (90-28degS, 28degS-28degN, 28-60degN and 60-90degN) as a function of emissions based on the forcing in those bands caused by the emissions. It is based on a large set of simulations performed with a single atmosphere-ocean climate model to derive regional forcing/response relationships. Here I evaluate the robustness of those relationships using the forcing/response portion of the ARTP to estimate regional temperature responses to the historic aerosol forcing in three independent climate models. These ARTP results are in good accord with the actual responses in those models. Nearly all ARTP estimates fall within +/-20%of the actual responses, though there are some exceptions for 90-28degS and the Arctic, and in the latter the ARTP may vary with forcing agent. However, for the tropics and the Northern Hemisphere mid-latitudes in particular, the +/-20% range appears to be roughly consistent with the 95% confidence interval. Land areas within these two bands respond 39-45% and 9-39% more than the latitude band as a whole. The ARTP, presented here in a slightly revised form, thus appears to provide a relatively robust estimate for the responses of large-scale latitude bands and land areas within those bands to inhomogeneous radiative forcing and thus potentially to emissions as well. Hence this metric could allow rapid evaluation of the effects of emissions policies at a finer scale than global metrics without requiring use of a full climate model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012SPIE.8494E..0GL','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012SPIE.8494E..0GL"><span id="translatedtitle"><span class="hlt">Absolute</span> optical surface measurement with deflectometry</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, Wansong; Sandner, Marc; Gesierich, Achim; Burke, Jan</p> <p></p> <p>Deflectometry utilises the deformation and displacement of a sample pattern after reflection from a test surface to infer the surface slopes. Differentiation of the measurement data leads to a curvature map, which is very useful for surface quality checks with sensitivity down to the nanometre range. Integration of the data allows reconstruction of the <span class="hlt">absolute</span> surface shape, but the procedure is very error-prone because systematic errors may add up to large shape deviations. In addition, there are infinitely many combinations for slope and object distance that satisfy a given observation. One solution for this ambiguity is to include information on the object's distance. It must be known very accurately. Two laser pointers can be used for positioning the object, and we also show how a confocal chromatic distance sensor can be used to define a reference point on a smooth surface from which the integration can be started. The used integration algorithm works without symmetry constraints and is therefore suitable for free-form surfaces as well. Unlike null testing, deflectometry also determines radius of curvature (ROC) or focal lengths as a direct result of the 3D surface reconstruction. This is shown by the example of a 200 mm diameter telescope mirror, whose ROC measurements by coordinate measurement machine and deflectometry coincide to within 0.27 mm (or a sag error of 1.3μm). By the example of a diamond-turned off-axis parabolic mirror, we demonstrate that the figure measurement uncertainty comes close to a well-calibrated Fizeau interferometer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19940024091&hterms=beer+lambert&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dbeer%2Blambert','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19940024091&hterms=beer+lambert&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dbeer%2Blambert"><span id="translatedtitle"><span class="hlt">Absolute</span> determination of local tropospheric OH concentrations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Armerding, Wolfgang; Comes, Franz-Josef</p> <p>1994-01-01</p> <p>Long path absorption (LPA) according to Lambert Beer's law is a method to determine <span class="hlt">absolute</span> concentrations of trace gases such as tropospheric OH. We have developed a LPA instrument which is based on a rapid tuning of the light source which is a frequency doubled dye laser. The laser is tuned across two or three OH absorption features around 308 nm with a scanning speed of 0.07 cm(exp -1)/microsecond and a repetition rate of 1.3 kHz. This high scanning speed greatly reduces the fluctuation of the light intensity caused by the atmosphere. To obtain the required high sensitivity the laser output power is additionally made constant and stabilized by an electro-optical modulator. The present sensitivity is of the order of a few times 10(exp 5) OH per cm(exp 3) for an acquisition time of a minute and an absorption path length of only 1200 meters so that a folding of the optical path in a multireflection cell was possible leading to a lateral dimension of the cell of a few meters. This allows local measurements to be made. Tropospheric measurements have been carried out in 1991 resulting in the determination of OH diurnal variation at specific days in late summer. Comparison with model calculations have been made. Interferences are mainly due to SO2 absorption. The problem of OH self generation in the multireflection cell is of minor extent. This could be shown by using different experimental methods. The minimum-maximum signal to noise ratio is about 8 x 10(exp -4) for a single scan. Due to the small size of the absorption cell the realization of an open air laboratory is possible in which by use of an additional UV light source or by additional fluxes of trace gases the chemistry can be changed under controlled conditions allowing kinetic studies of tropospheric photochemistry to be made in open air.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016ISPAr41B1..271A&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016ISPAr41B1..271A&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Absolute</span> Radiometric Calibration of KOMPSAT-3A</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ahn, H. Y.; Shin, D. Y.; Kim, J. S.; Seo, D. C.; Choi, C. U.</p> <p>2016-06-01</p> <p>This paper presents a vicarious radiometric calibration of the Korea Multi-Purpose Satellite-3A (KOMPSAT-3A) performed by the Korea Aerospace Research Institute (KARI) and the Pukyong National University Remote Sensing Group (PKNU RSG) in 2015.The primary stages of this study are summarized as follows: (1) A field campaign to determine radiometric calibrated target fields was undertaken in Mongolia and South Korea. Surface reflectance data obtained in the campaign were input to a radiative transfer code that predicted at-sensor radiance. Through this process, equations and parameters were derived for the KOMPSAT-3A sensor to enable the conversion of calibrated DN to physical units, such as at-sensor radiance or TOA reflectance. (2) To validate the <span class="hlt">absolute</span> calibration coefficients for the KOMPSAT-3A sensor, we performed a radiometric validation with a comparison of KOMPSAT-3A and Landsat-8 TOA reflectance using one of the six PICS (Libya 4). Correlations between top-of-atmosphere (TOA) radiances and the spectral band responses of the KOMPSAT-3A sensors at the Zuunmod, Mongolia and Goheung, South Korea sites were significant for multispectral bands. The average difference in TOA reflectance between KOMPSAT-3A and Landsat-8 image over the Libya 4, Libya site in the red-green-blue (RGB) region was under 3%, whereas in the NIR band, the TOA reflectance of KOMPSAT-3A was lower than the that of Landsat-8 due to the difference in the band passes of two sensors. The KOMPSAT-3Aensor includes a band pass near 940 nm that can be strongly absorbed by water vapor and therefore displayed low reflectance. Toovercome this, we need to undertake a detailed analysis using rescale methods, such as the spectral bandwidth adjustment factor.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_25 --> <center> <div class="footer-extlink text-muted"><small>Some links on this page may take you to non-federal websites. 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