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Sample records for positive dynamic topography

  1. Dynamic Topography Revisited

    Science.gov (United States)

    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

  2. Topography of the Betics: crustal thickening, dynamic topography and relief inheritance

    Science.gov (United States)

    Janowski, Marianne; Loget, Nicolas; Bellahsen, Nicolas; Husson, Laurent; Le Pourhiet, Laetitia; Meyer, Bertrand

    2017-04-01

    The main mechanism that explains high orogenic topographies is the isostatic adjustment due to crustal thickening. However in the Betic Cordillera (South Spain), the present-day elevation and crustal thickness are not correlated. That is at odds with the general premise of isostasy and requires reappraising the question of the driving mechanisms leading to the current topography. The Betics are located at the western edge of the alpine Mediterranean belt. Its Cenozoic orogenic building was disrupted by a major crustal thinning event induced by a slab rollback in the internal zones (Alboran domain) during Neogene. Topography was largely levelled and flooded by the sea during Neogene extension, and then has been folded since the Late Tortonian inversion. The present-day topography shows flat summits still preserved from fluvial regression in the internal zones (central and eastern Betics). These low-relief surfaces may be inherited from the Neogene planation toward sea-level as rocks cooling histories inferred from low-temperature thermochronology seem to point it out. Post-Tortonian shortening estimated thanks to a crustal-scale N-S cross-section in the eastern Betics (at the Sierra Nevada longitude) does not exceed few kilometers which is much lower than the shortening required by isostatic equilibrium, and is thus insufficient to explain the post-Tortonian topography building. We tested the hypothesis that mantle dynamics could in fact be an important mechanism that explains the topography of the Betics. We first computed the residual topography (i.e. the non-isostatic component of the elevation) using the most recent published Moho mapping of the area. In the western Betics, our results show important negative residual topography (down to -3 km) possibly associated with the west-Alboran slab suction. In the eastern Betics however, positive residual topography is important (up to +3 km) and can be explained by the dynamic mantle support of the topography, possibly

  3. Mean Dynamic Topography of the Arctic Ocean

    Science.gov (United States)

    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.

  4. Ocean Dynamic Topography from GPS - Galathea-3 First results

    DEFF Research Database (Denmark)

    Andersen, Ole Baltazar; Olesen, Arne Vestergaard; Forsberg, René

    2010-01-01

    From August 14, 2006–April 24, 2007 the Danish expedition called Galathea-3 circumnavigated the globe. The Danish Technical University, DTU space, participated in the expedition with two experiments on-board. From Perth in Australia to Copenhagen Denmark measurements of the exact position and mov...... to permanent currents in the ocean. Comparison with the DNSC08 mean dynamic topography derived from satellite altimetry across the Gulf Stream yields agreement on the 20 cm level, which is a very satisfactory preliminary result calling for further refinement of the technique....

  5. Determining Coastal Mean Dynamic Topography by Geodetic Methods

    Science.gov (United States)

    Huang, Jianliang

    2017-11-01

    In geodesy, coastal mean dynamic topography (MDT) was traditionally determined by spirit leveling technique. Advances in navigation satellite positioning (e.g., GPS) and geoid determination enable space-based leveling with an accuracy of about 3 cm at tide gauges. Recent CryoSat-2, a satellite altimetry mission with synthetic aperture radar (SAR) and SAR interferometric measurements, extends the space-based leveling to the coastal ocean with the same accuracy. However, barriers remain in applying the two space-based geodetic methods for MDT determination over the coastal ocean because current geoid modeling focuses primarily on land as a substitute to spirit leveling to realize the vertical datum.

  6. Elucidating Dynamical Processes Relevant to Flow Encountering Abrupt Topography (FLEAT)

    Science.gov (United States)

    2015-09-30

    Encountering Abrupt Topography (FLEAT) Bo Qiu Dept of Oceanography, University of Hawaii at Manoa 1000 Pope Rd. Honolulu, HI 96822 phone: (808) 956...c) to explore relevant dynamics by using both simplified models and OGCM output with realistic topography and surface boundary conditions...scale abyssal circulation, we propose to use the Hallberg Isopycnal Model (HIM). The HIM allows sloping isopycnals to interact with bottom topography

  7. Importance of dynamic topography in Himalaya-Tibetan plateau region

    Science.gov (United States)

    Ghosh, A.; Singh, S.

    2017-12-01

    Himalaya-Tibetan plateau region has the highest topography in the world. Various studies have been done to understand the mechanisms responsible for sustaining this high topography. However, the existence of dynamic topography in this region is still uncertain, though there have been some studies exploring the role of channel flow in lower crust leading to some topography. We investigated the role of radial mantle flow in this region by studying the relationship between geoid and topography. High geoid-to-topography ratios (GTR) were observed along the Himalayas suggesting deeper compensation mechanisms. However, further north, the geoid and topography relationship became a lot more complex as high as well as low GTR values were observed. The high GTR regions also coincided with area of high filtered free air gravity anomalies, indicating dynamic support. We also looked at the spectral components of gravity, geoid and topography, and calculated response functions to distinguish between different compensation mechanisms. We estimated the average elastic thickness of the whole region to be around 40 km from coherence and admittance studies. The GTR and admittance-coherence studies suggest deeper mass anomalies playing a role in supporting the topography along Himalayas and the area between Altyn Tagh and Kunlun faults.

  8. Influence of dynamic topography on landscape evolution and passive continental margin stratigraphy

    Science.gov (United States)

    Ding, Xuesong; Salles, Tristan; Flament, Nicolas; Rey, Patrice

    2017-04-01

    Quantifying the interaction between surface processes and tectonics/deep Earth processes is one important aspect of landscape evolution modelling. Both observations and results from numerical modelling indicate that dynamic topography - a surface expression of time-varying mantle convection - plays a significant role in shaping landscape through geological time. Recent research suggests that dynamic topography also has non-negligible effects on stratigraphic architecture by modifying accommodation space available for sedimentation. In addition, dynamic topography influences the sediment supply to continental margins. We use Badlands to investigate the evolution of a continental-scale landscape in response to transient dynamic uplift or subsidence, and to model the stratigraphic development on passive continental margins in response to sea-level change, thermal subsidence and dynamic topography. We consider a circularly symmetric landscape consisting of a plateau surrounded by a gently sloping continental plain and a continental margin, and a linear wave of dynamic topography. We analyze the evolution of river catchments, of longitudinal river profiles and of the χ values to evaluate the dynamic response of drainage systems to dynamic topography. We calculate the amount of cumulative erosion and deposition, and sediment flux at shoreline position, as a function of precipitation rate and erodibility coefficient. We compute the stratal stacking pattern and Wheeler diagram on vertical cross-sections at the continental margin. Our results indicate that dynamic topography 1) has a considerable influence on drainage reorganization; 2) contributes to shoreline migration and the distribution of depositional packages by modifying the accommodation space; 3) affects sediment supply to the continental margin. Transient dynamic topography contributes to the migration of drainage divides and to the migration of the mainstream in a drainage basin. The dynamic uplift

  9. DNSC08 mean sea surface and mean dynamic topography models

    DEFF Research Database (Denmark)

    Andersen, Ole Baltazar; Knudsen, Per

    2009-01-01

    -2004. It is the first global MSS without a polar gap including all of the Arctic Ocean by including laser altimetry from the ICESat mission. The mean dynamic topography (MDT) is the quantity that bridges the geoid and the mean sea surface constraining large-scale ocean circulation. Here we present a new high...

  10. Decoding Dynamic Topography: Geologic and Thermochronologic Constraints From Madagascar

    Science.gov (United States)

    Stephenson, S.; White, N.

    2017-12-01

    Madagascar's topography is characterized by flights of low relief peneplains separated by escarpments. Remarkably, nearly 50% of the landscape is higher than 500 m despite being surrounded by passive margins. Eocene marine limestones crop out at elevations of 400-800 m, staircases of Pleistocene marine terraces fringe the coastline and longitudinal river profiles are disequilibrated. Together, these observations suggest that Madagascar has experienced Neogene epeirogenic uplift. Positive oceanic residual depth anomalies surrounding the island, long wavelength free-air gravity anomalies, Neogene basaltic volcanism and slow sub-plate shear wave velocities show that Neogene uplift is generated by convective circulation within the upper mantle. However, the landscape's erosional response to long wavelength uplift is poorly known. Here, we present 18 apatite fission track and apatite He analyses of granitoid samples from sub-vertical transects in central and northern Madagascar. Apatite fission track ages are 200-250 Ma with mean track lengths of 12 μm. Apatite He ages are highly dispersed in samples from the highlands (i.e. AHe age > 150 Ma) but a narrower, younger range of 30-60 Ma is found on the coastal lowlands. Joint inverse modeling was carried out using the QTQt transdimensional reversible jump Markov Chain Monte Carlo (MCMC) algorithm to determine time-temperature histories. Results show that the coastal lowlands experienced up to 1 km of exhumation during the Neogene Period, whilst the central highlands experienced either very slow or negligible exhumation. This spatial distribution is expected when kinematic waves of incision propagate through a fluvially eroding landscape from coast to interior. Inverse modeling of suites of river profiles and forward landscape simulations support this interpretation. Our results show that the landscape response to modest (i.e. 1 km) regional uplift is diachronous and that thermochronologic observations can be used to

  11. Dynamic topography and the Cenozoic carbonate compensation depth

    Science.gov (United States)

    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.

  12. 3-D subduction dynamics in the western Pacific: Mantle pressure, plate kinematics, and dynamic topography.

    Science.gov (United States)

    Holt, A. F.; Royden, L.; Becker, T. W.; Faccenna, C.

    2017-12-01

    While it is well established that the slab pull of negatively buoyant oceanic plates is the primary driving force of plate tectonics, the dynamic "details" of subduction have proved difficult to pin down. We use the Philippine Sea Plate region of the western Pacific as a site to explore links between kinematic observables (e.g. topography and plate motions) and the dynamics of the subduction system (e.g. mantle flow, mantle pressure). To first order, the Philippine Sea Plate can be considered to be the central plate of a double slab system containing two slabs that dip in the same direction, to the west. This subduction configuration presents the opportunity to explore subduction dynamics in a setting where two closely spaced slabs interact via subduction-induced mantle flow and stresses transmitted through the intervening plate. We use a 3-D numerical approach (e.g. Holt et al., 2017), augmented by semi-analytical models (e.g. Jagoutz et al., 2017), to develop relationships between dynamic processes and kinematic properties, including plate velocities, lithospheric stress state, slab dip angles, and topography. When combined with subduction zone observables, this allows us to isolate the first order dynamic processes that are in operation in the Philippine Sea Plate region. Our results suggest that positive pressure build-up occurs in the asthenosphere between the two slabs (Izu-Bonin-Mariana and Ryukyu-Nankai), and that this is responsible for producing much of the observed kinematic variability in the region, including the steep dip of the Pacific slab at the Izu-Bonin-Mariana trench, as compared to the flat dip of the Pacific slab north of Japan. We then extend our understanding of the role of asthenospheric pressure to examine the forces responsible for the plate kinematics and dynamic topography of the entire Western Pacific subduction margin(s). References:Holt, A. F., Royden, L. H., Becker, T. W., 2017. Geophys. J. Int., 209, 250-265Jagoutz, O., Royden, L

  13. Global patterns in Earth's dynamic topography since the Jurassic: the role of subducted slabs

    Directory of Open Access Journals (Sweden)

    M. Rubey

    2017-09-01

    Full Text Available We evaluate the spatial and temporal evolution of Earth's long-wavelength surface dynamic topography since the Jurassic using a series of high-resolution global mantle convection models. These models are Earth-like in terms of convective vigour, thermal structure, surface heat-flux and the geographic distribution of heterogeneity. The models generate a degree-2-dominated spectrum of dynamic topography with negative amplitudes above subducted slabs (i.e. circum-Pacific regions and southern Eurasia and positive amplitudes elsewhere (i.e. Africa, north-western Eurasia and the central Pacific. Model predictions are compared with published observations and subsidence patterns from well data, both globally and for the Australian and southern African regions. We find that our models reproduce the long-wavelength component of these observations, although observed smaller-scale variations are not reproduced. We subsequently define geodynamic rules for how different surface tectonic settings are affected by mantle processes: (i locations in the vicinity of a subduction zone show large negative dynamic topography amplitudes; (ii regions far away from convergent margins feature long-term positive dynamic topography; and (iii rapid variations in dynamic support occur along the margins of overriding plates (e.g. the western US and at points located on a plate that rapidly approaches a subduction zone (e.g. India and the Arabia Peninsula. Our models provide a predictive quantitative framework linking mantle convection with plate tectonics and sedimentary basin evolution, thus improving our understanding of how subduction and mantle convection affect the spatio-temporal evolution of basin architecture.

  14. Dynamic wetting and spreading and the role of topography

    International Nuclear Information System (INIS)

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

    2009-01-01

    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, v e , to the dynamic and equilibrium contact angles θ and θ e through v e ∝θ(θ 2 -θ 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 dependence of dynamic contact angle on time is

  15. The updated geodetic mean dynamic topography model – DTU15MDT

    DEFF Research Database (Denmark)

    Knudsen, Per; Andersen, Ole Baltazar; Maximenko, Nikolai

    An update to the global mean dynamic topography model DTU13MDT is presented. For DTU15MDT the newer gravity model EIGEN-6C4 has been combined with the DTU15MSS mean sea surface model to construct this global mean dynamic topography model. The EIGEN-6C4 is derived using the full series of GOCE data...

  16. French Polynesia Hotspot Swells Explained By Dynamic Topography

    Science.gov (United States)

    Adam, C.; Yoshida, M.; Isse, T.; Suetsugu, D.; Shiobara, H.; Sugioka, H.; Kanazawa, T.; Fukao, Y.; Barruol, G.

    2007-12-01

    Situated on the South Pacific Superswell, French Polynesia is a region characterized by numerous geophysical anomalies among which a high volcanism concentration. Seven hotspots are required to explain the observed chains, volcanism ages and geochemical trends. Many open questions still remain on the origin of these hotspot chains: are they created by passive uplift of magma due to discontinuities in the structure of the lithosphere or by the ascent of mantle plumes? In this case, at which depth do these plumes initiate in the mantle? Many geophysical observations (bathymetry, gravity, magnetism, volcanism ages..) are used to understand the unique phenomenon occurring on this region. The most useful information may come from tomography models since they provide a 3D view of the mantle. Until recently, the tomography models over the region were quite inaccurate because of the sparse location of the seismic stations. The deployment of two new seismic stations networks (BBOBS and temporary island stations) has lately remedied this failing. The resulting tomography model obtained through the inversion of Rayleigh waves provides the most accurate view of the shallowest part of the mantle (depths ≤ 240 km) beneath French Polynesia. Indeed, for the first time the accuracy of a tomography model is good enough to provide information about plume phenomenology in this complex region. In order to quantify the plumes effect on the seafloor, we compute the dynamic topography through an instantaneous flow model. The general trend of the observed depths anomalies (highs and lows) is well recovered. For example the amplitude, location and extension of the swells associated with the Society, Macdonald and Rarotonga are accurately described by the dynamic model. We also find that dynamic uplift is associated with the Tuamotu archipelago which means that a part of the observed swell is due to the present day action of plumes. Since no volcanism ages are available over this chain

  17. Insight into collision zone dynamics from topography: numerical modelling results and observations

    OpenAIRE

    A. D. Bottrill; J. van Hunen; M. B. Allen

    2012-01-01

    Dynamic models of subduction and continental collision are used to predict dynamic topography changes on the overriding plate. The modelling results show a distinct evolution of topography on the overriding plate, during subduction, continental collision and slab break-off. A prominent topographic feature is a temporary (few Myrs) deepening in the area of the back arc-basin after initial collision. This collisional mantle dynamic basin (CMDB) is caused by slab steepening drawing material away...

  18. Thruster allocation for dynamical positioning

    NARCIS (Netherlands)

    Poppe, K.; van den Berg, J.B.; Blank, E.; Archer, C.; Redeker, M.; Kutter, M.; Hemker, P.

    2010-01-01

    Positioning a vessel at a fixed position in deep water is of great importance when working offshore. In recent years a Dynamical Positioning (DP) system was developed at Marin [2]. After the measurement of the current position and external forces (like waves, wind etc.), each thruster of the vessel

  19. Effect of surface topography upon micro-impact dynamics

    International Nuclear Information System (INIS)

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

    2016-01-01

    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. (paper)

  20. Effects of upper mantle heterogeneities on the lithospheric stress field and dynamic topography

    Science.gov (United States)

    Osei Tutu, Anthony; Steinberger, Bernhard; Sobolev, Stephan V.; Rogozhina, Irina; Popov, Anton A.

    2018-05-01

    The orientation and tectonic regime of the observed crustal/lithospheric stress field contribute to our knowledge of different deformation processes occurring within the Earth's crust and lithosphere. In this study, we analyze the influence of the thermal and density structure of the upper mantle on the lithospheric stress field and topography. We use a 3-D lithosphere-asthenosphere numerical model with power-law rheology, coupled to a spectral mantle flow code at 300 km depth. Our results are validated against the World Stress Map 2016 (WSM2016) and the observation-based residual topography. We derive the upper mantle thermal structure from either a heat flow model combined with a seafloor age model (TM1) or a global S-wave velocity model (TM2). We show that lateral density heterogeneities in the upper 300 km have a limited influence on the modeled horizontal stress field as opposed to the resulting dynamic topography that appears more sensitive to such heterogeneities. The modeled stress field directions, using only the mantle heterogeneities below 300 km, are not perturbed much when the effects of lithosphere and crust above 300 km are added. In contrast, modeled stress magnitudes and dynamic topography are to a greater extent controlled by the upper mantle density structure. After correction for the chemical depletion of continents, the TM2 model leads to a much better fit with the observed residual topography giving a good correlation of 0.51 in continents, but this correction leads to no significant improvement of the fit between the WSM2016 and the resulting lithosphere stresses. In continental regions with abundant heat flow data, TM1 results in relatively small angular misfits. For example, in western Europe the misfit between the modeled and observation-based stress is 18.3°. Our findings emphasize that the relative contributions coming from shallow and deep mantle dynamic forces are quite different for the lithospheric stress field and dynamic

  1. Dynamics of Lithospheric Extension and Residual Topography in Southern Tibet

    Science.gov (United States)

    Chen, B.; Shahnas, M. H.; Pysklywec, R.; Sengul Uluocak, E.

    2017-12-01

    Although the north-south (N-S) convergence between India and Eurasia is ongoing, a number of north-south trending rifts (e.g., Tangra Yum Co Rift, Yadong-Gulu Rift and Cona Rift) and normal faulting are observed at the surface of southern Tibet, suggesting an east-west (E-W) extension tectonic regime. The earthquake focal mechanisms also show that deformation of southern Tibet is dominated by E-W extension across these N-S trending rifts. Because the structure of the lithosphere and underlying mantle is poorly understood, the origin of the east-west extension of southern Tibet is still under debate. Gravitational collapse, oblique convergence, and mantle upwelling are among possible responsible mechanisms. We employ a 3D-spherical control volume model of the present-day mantle flow to understand the relationship between topographic features (e.g., rifts and the west-east extension), intermediate-depth earthquakes, and tectonic stresses induced by mantle flow beneath the region. The thermal structure of the mantle and crust is obtained from P and S-wave seismic inversions and heat flow data. Power-law creep with viscous-plastic rheology, describing the behavior of the lithosphere and mantle material is employed. We determine the models which can best reconcile the observed features of southern Tibet including surface heat flow, residual topography with uplift and subsidence, reported GPS rates of the vertical movements, and the earthquake events. The 3D geodynamic modeling of the contemporary mantle flow-lithospheric response quantifies the relative importance of the various proposed mechanism responsible for the E-W extension and deep earthquakes in southern Tibet. The results also have further implications for the magmatic activities and crustal rheology of the region.

  2. The coastal mean dynamic topography in Norway observed by CryoSat-2 and GOCE

    DEFF Research Database (Denmark)

    Idžanović, Martina; Ophaug, Vegard; Andersen, Ole Baltazar

    2017-01-01

    New-generation synthetic aperture radar altimetry, as implemented on CryoSat-2, observes sea surface heights in coastal areas that were previously not monitored by conventional altimetry. Therefore,CryoSat-2 is expected to improve the coastal mean dynamic topography (MDT). However, the MDT remains...

  3. The DTU12MDT global mean dynamic topography and ocean circulation model

    DEFF Research Database (Denmark)

    Knudsen, Per; Andersen, Ole B.

    2013-01-01

    combined with the DTU10MSS mean sea surface model to construct a global mean dynamic topography model named DTU10MDT. The results of analyses clearly demonstrated the value of the GOCE mission. Both the resolution and the estimation of the surface currents have been improved significantly compared...

  4. Enhanced Mean Dynamic Topography And Ocean Circulation Estimation Using Goce Preliminary Mode

    DEFF Research Database (Denmark)

    Knudsen, Per; Bingham, Rory; Andersen, Ole Baltazar

    2011-01-01

    have been combined with the recent DNSC08MSS mean sea surface model to construct a global GOCE satellite-only mean dynamic topography model. At a first glance, the GOCE MDT display the well known features related to the major ocean current systems. A closer look, however, reveals that the improved...

  5. Detection of a dynamic topography signal in last interglacial sea-level records.

    Science.gov (United States)

    Austermann, Jacqueline; Mitrovica, Jerry X; Huybers, Peter; Rovere, Alessio

    2017-07-01

    Estimating minimum ice volume during the last interglacial based on local sea-level indicators requires that these indicators are corrected for processes that alter local sea level relative to the global average. Although glacial isostatic adjustment is generally accounted for, global scale dynamic changes in topography driven by convective mantle flow are generally not considered. We use numerical models of mantle flow to quantify vertical deflections caused by dynamic topography and compare predictions at passive margins to a globally distributed set of last interglacial sea-level markers. The deflections predicted as a result of dynamic topography are significantly correlated with marker elevations (>95% probability) and are consistent with construction and preservation attributes across marker types. We conclude that a dynamic topography signal is present in the elevation of last interglacial sea-level records and that the signal must be accounted for in any effort to determine peak global mean sea level during the last interglacial to within an accuracy of several meters.

  6. Sequential assimilation of multi-mission dynamical topography into a global finite-element ocean model

    Directory of Open Access Journals (Sweden)

    S. Skachko

    2008-12-01

    Full Text Available This study focuses on an accurate estimation of ocean circulation via assimilation of satellite measurements of ocean dynamical topography into the global finite-element ocean model (FEOM. The dynamical topography data are derived from a complex analysis of multi-mission altimetry data combined with a referenced earth geoid. The assimilation is split into two parts. First, the mean dynamic topography is adjusted. To this end an adiabatic pressure correction method is used which reduces model divergence from the real evolution. Second, a sequential assimilation technique is applied to improve the representation of thermodynamical processes by assimilating the time varying dynamic topography. A method is used according to which the temperature and salinity are updated following the vertical structure of the first baroclinic mode. It is shown that the method leads to a partially successful assimilation approach reducing the rms difference between the model and data from 16 cm to 2 cm. This improvement of the mean state is accompanied by significant improvement of temporal variability in our analysis. However, it remains suboptimal, showing a tendency in the forecast phase of returning toward a free run without data assimilation. Both the mean difference and standard deviation of the difference between the forecast and observation data are reduced as the result of assimilation.

  7. Reconciling Long-Wavelength Dynamic Topography, Geoid Anomalies and Mass Distribution on Earth

    Science.gov (United States)

    Hoggard, M.; Richards, F. D.; Ghelichkhan, S.; Austermann, J.; White, N.

    2017-12-01

    Since the first satellite observations in the late 1950s, we have known that that the Earth's non-hydrostatic geoid is dominated by spherical harmonic degree 2 (wavelengths of 16,000 km). Peak amplitudes are approximately ± 100 m, with highs centred on the Pacific Ocean and Africa, encircled by lows in the vicinity of the Pacific Ring of Fire and at the poles. Initial seismic tomography models revealed that the shear-wave velocity, and therefore presumably the density structure, of the lower mantle is also dominated by degree 2. Anti-correlation of slow, probably low density regions beneath geoid highs indicates that the mantle is affected by large-scale flow. Thus, buoyant features are rising and exert viscous normal stresses that act to deflect the surface and core-mantle boundary (CMB). Pioneering studies in the 1980s showed that a viscosity jump between the upper and lower mantle is required to reconcile these geoid and tomographically inferred density anomalies. These studies also predict 1-2 km of dynamic topography at the surface, dominated by degree 2. In contrast to this prediction, a global observational database of oceanic residual depth measurements indicates that degree 2 dynamic topography has peak amplitudes of only 500 m. Here, we attempt to reconcile observations of dynamic topography, geoid, gravity anomalies and CMB topography using instantaneous flow kernels. We exploit a density structure constructed from blended seismic tomography models, combining deep mantle imaging with higher resolution upper mantle features. Radial viscosity structure is discretised, and we invert for the best-fitting viscosity profile using a conjugate gradient search algorithm, subject to damping. Our results suggest that, due to strong sensitivity to radial viscosity structure, the Earth's geoid seems to be compatible with only ± 500 m of degree 2 dynamic topography.

  8. Identification of Dynamically Positioned Ships

    Directory of Open Access Journals (Sweden)

    Thor I. Fossen

    1996-04-01

    Full Text Available Todays model-based dynamic positioning (DP systems require that the ship and thruster dynamics are known with some accuracy in order to use linear quadratic optical control theory. However, it is difficult to identify the mathematical model of a dynamically posititmed (DP ship since the ship is not persistently excited under DP. In addition the ship parameter estimation problem is nonlinear and multivariable with only position and thruster state measurements available for parameter estimation. The process and measurement noise must also be modeled in order to avoid parameter drift due to environmental disturbances and sensor failure. This article discusses an off-line parallel extended Kalman filter (EKF algorithm utilizing two measurement series in parallel to estimate the parameters in the DP ship model. Full-scale experiments with a supply vessel are used to demonstrate the convergence and robustness of the proposed parameter estimator.

  9. Impact of the lithosphere on dynamic topography: Insights from analogue modeling

    OpenAIRE

    Sembroni, Andrea; Kiraly, Agnes; Faccenna, Claudio; Funiciello, Francesca; Becker, Thorsten W.; Goblig, Jan; Fernandez, Manel

    2017-01-01

    Density anomalies beneath the lithosphere are expected to generate dynamic topography at the Earth's surface due to the induced mantle flow stresses which scale linearly with density anomalies, while the viscosity of the upper mantle is expected to control uplift rates. However, limited attention has been given to the role of the lithosphere. Here we present results from analogue modeling of the interactions between a density anomaly rising in the mantle and the lithosphere in a Newtonian sys...

  10. Insight into collision zone dynamics from topography: numerical modelling results and observations

    Directory of Open Access Journals (Sweden)

    A. D. Bottrill

    2012-11-01

    Full Text Available Dynamic models of subduction and continental collision are used to predict dynamic topography changes on the overriding plate. The modelling results show a distinct evolution of topography on the overriding plate, during subduction, continental collision and slab break-off. A prominent topographic feature is a temporary (few Myrs basin on the overriding plate after initial collision. This "collisional mantle dynamic basin" (CMDB is caused by slab steepening drawing, material away from the base of the overriding plate. Also, during this initial collision phase, surface uplift is predicted on the overriding plate between the suture zone and the CMDB, due to the subduction of buoyant continental material and its isostatic compensation. After slab detachment, redistribution of stresses and underplating of the overriding plate cause the uplift to spread further into the overriding plate. This topographic evolution fits the stratigraphy found on the overriding plate of the Arabia-Eurasia collision zone in Iran and south east Turkey. The sedimentary record from the overriding plate contains Upper Oligocene-Lower Miocene marine carbonates deposited between terrestrial clastic sedimentary rocks, in units such as the Qom Formation and its lateral equivalents. This stratigraphy shows that during the Late Oligocene–Early Miocene the surface of the overriding plate sank below sea level before rising back above sea level, without major compressional deformation recorded in the same area. Our modelled topography changes fit well with this observed uplift and subsidence.

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

    Science.gov (United States)

    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

  12. The impact of dynamic topography on the bedrock elevation and volume of the Pliocene Antarctic Ice Sheet

    Science.gov (United States)

    Austermann, Jacqueline; Pollard, David; Mitrovica, Jerry X.; Moucha, Robert; Forte, Alessandro M.; DeConto, Robert M.

    2015-04-01

    Reconstructions of the Antarctic ice sheet over long timescales (i.e. Myrs) require estimates of bedrock elevation through time. Ice sheet models have accounted, with varying levels of sophistication, for changes in the bedrock elevation due to glacial isostatic adjustment (GIA), but they have neglected other processes that may perturb topography. One notable example is dynamic topography, the deflection of the solid surface of the Earth due to convective flow within the mantle. Numerically predicted changes in dynamic topography have been used to correct paleo shorelines for this departure from eustasy, but the effect of such changes on ice sheet stability is unknown. In this study we use numerical predictions of time-varying dynamic topography to reconstruct bedrock elevation below the Antarctic ice sheet during the mid Pliocene warm period (~3 Ma). Moreover, we couple this reconstruction to a three-dimensional ice sheet model to explore the impact of dynamic topography on the evolution of the Antarctic ice sheet since the Pliocene. Our modeling indicates significant uplift in the area of the Transantarctic Mountains (TAM) and the adjacent Wilkes basin. This predicted uplift, which is at the lower end of geological inferences of uplift of the TAM, implies a lower elevation of the basin in the Pliocene. Relative to simulations that do not include dynamic topography, the lower elevation leads to a smaller Antarctic Ice Sheet volume and a more significant retreat of the grounding line in the Wilkes basin, both of which are consistent with offshore sediment core data. We conclude that reconstructions of the Antarctic Ice Sheet during the mid-Pliocene warm period should be based on bedrock elevation models that include the impact of both GIA and dynamic topography.

  13. Interferometer for measuring the dynamic surface topography of a human tear film

    Science.gov (United States)

    Primeau, Brian C.; Greivenkamp, John E.

    2012-03-01

    The anterior refracting surface of the eye is the thin tear film that forms on the surface of the cornea. Following a blink, the tear film quickly smoothes and starts to become irregular after 10 seconds. This irregularity can affect comfort and vision quality. An in vivo method of characterizing dynamic tear films has been designed based upon a near-infrared phase-shifting interferometer. This interferometer continuously measures light reflected from the tear film, allowing sub-micron analysis of the dynamic surface topography. Movies showing the tear film behavior can be generated along with quantitative metrics describing changes in the tear film surface. This tear film measurement allows analysis beyond capabilities of typical fluorescein visual inspection or corneal topography and provides better sensitivity and resolution than shearing interferometry methods. The interferometer design is capable of identifying features in the tear film much less than a micron in height with a spatial resolution of about ten microns over a 6 mm diameter. This paper presents the design of the tear film interferometer along with the considerations that must be taken when designing an interferometer for on-eye diagnostics. Discussions include eye movement, design of null optics for a range of ocular geometries, and laser emission limits for on-eye interferometry.

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

    Science.gov (United States)

    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.

  15. Molecular dynamics investigation of nanoscale substrate topography and its interaction with liquids

    Science.gov (United States)

    Cordeiro Rodrigues, Jhonatam

    Nanotechnology has been presenting successful applications in several areas. However, experimentation with nanoscale materials is costly and limited in analysis capability. This research investigates the use of molecular dynamics (MD) simulations to model and study nanomaterials and manufacturing processes. MD simulations are employed to reduce cost, optimize design, increase productivity and allow for the investigation of material interactions not yet observable through experimentation. This work investigates the interaction of water with substrates at the nanoscale. The effect of temperature, droplet impingement velocities and size, as well as substrate material, are investigated at the nanoscale. Several substrate topography designs were modeled to reveal their influence on the wettability of the substrate. Nanoscale gold and silicon substrates are more hydrophilic at higher temperatures than at room temperature. The reduction in droplet diameter increases its wettability. High impingement velocity of droplets does not influence final wettability of substrates but induces higher diffusion rates of droplets in a heated environment. Droplets deposited over a gradient of surface exposure presents spontaneous movement. The Leidenfrost effect was investigated at the nanoscale. Droplets of 4 and 10nm in diameter presented behaviors pertinent to the Leidenfrost effect at 373K, significantly lower than at micro scale and of potential impact to the field. Topographical features were manipulated using superhydrophobic coating resulting in micro whiskers. Nanoimprint lithography (NIL) was used to manufacture substrate topographies at the nanoscale. Water droplets were deposited on the substrates and their wettability was measured using droplet contact angles. Lower surface area exposure resulted in higher contact angles. The experimental relationships between surface topography and substrate wettability were used to validate the insights gained from MD simulations for

  16. Mean dynamic topography over Peninsular Malaysian seas using multimission satellite altimetry

    Science.gov (United States)

    Abazu, Isaac Chidi; Din, Ami Hassan Md; Omar, Kamaludin Mohd

    2017-04-01

    The development of satellite altimeters (SALTs) has brought huge benefits, among which is the ability to more adequately sense ocean-surface topography. The radar altimeter database system was used to capture and process ENVISAT, CRYOSAT-2, SARAL, JASON-1, and JASON-2 SALT data of 5 years between 2011 and 2015. The time series of monthly multimission SALT data showed an estimated sea level trend of 1.0, 2.4, 2.4, 3.6, and 12.0 mm/year at Gelang, Port Kelang, Kukup, Cendering, and Keling. The correlation analysis for the selected tide gauge stations produced satisfying results of R-squared with 0.86, 0.89, 0.91, and 0.97 for Cendering, Sedili, Gelang, and Geting, respectively. The ITG-Grace2010s geoid model was used to compute the mean dynamic topography (MDT) and plot to a grid of 0.25 deg for the Malacca Strait and South China Sea of Peninsular Malaysia, with Keling, Port Kelang, Geting, Sedili, and Johor Bahru tide gauge stations having values determined by interpolation to be 1.14, 1.19, 1.26, 1.88, and 2.91 m, respectively. MDT is computed from the SALT with respect to Port Kelang, the north-south sea slope ranges between -0.64 and 0.29 m/50 km and -0.01 and 0.52 m/50 km along the east and west coasts of Peninsular Malaysia, respectively.

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

    DEFF Research Database (Denmark)

    Andersen, Ole Baltazar; Knudsen, Per; Nielsen, Karina

    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...... 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......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...

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

    Science.gov (United States)

    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

  19. The impact of dynamic topography change on Antarctic Ice Sheet stability during the Mid-Pliocene Warm Period

    Science.gov (United States)

    Austermann, J.; Pollard, D.; Mitrovica, J. X.; Moucha, R.; Forte, A. M.; Deconto, R. M.; Rowley, D. B.; Raymo, M. E.

    2015-12-01

    The mid-Pliocene warm period (MPWP; ~ 3Ma), characterized by globally elevated temperatures (2-3º C) and carbon dioxide levels of ~400ppm, is commonly used as a testing ground for investigating ice sheet stability in a slightly warmer world. The central, unanswered question in this regard is the extent of East Antarctic melting during the MPWP. Here we assess the potential role of dynamic topography on this issue. Model reconstructions of the evolution of the Antarctic ice sheet during the ice age require an estimate of bedrock elevation through time. Ice sheet models account for changes in bedrock elevation due to glacial isostatic adjustment (GIA), often using simplified models of the GIA process, but they generally do not consider other processes that may perturb subglacial topography. One such notable process is dynamic topography, i.e. the deflection of the solid surface of the Earth due to convective flow and buoyancy variations within the mantle and lithosphere. Paleo-shorelines of Pliocene age reflect the influence of dynamic topography, but the impact of these bedrock elevation changes on ice sheet stability in the Antarctic region is unknown. In this study we use viscous flow simulations of mantle dynamics to predict changes in dynamic topography and reconstruct bedrock elevations below the Antarctic Ice Sheet since the MPWP. We furthermore couple this reconstruction to a three-dimensional ice sheet model in order to explore the impact of dynamic topography on the extent of the Antarctic Ice Sheet during the Pliocene. Our modeling indicates that uplift occurred in the area of the Transantarctic Mountains and the adjacent Wilkes Basin. This predicted uplift, which is consistent with geological inferences of uplift in the Transantarctic Mountains, implies a significantly (~100-200 m) lower elevation of the Wilkes Basin in the Pliocene. This lower elevation leads to ~400 km of additional retreat of the grounding line in this region relative to simulations

  20. On the assimilation of absolute geodetic dynamic topography in a global ocean model: impact on the deep ocean state

    Science.gov (United States)

    Androsov, Alexey; Nerger, Lars; Schnur, Reiner; Schröter, Jens; Albertella, Alberta; Rummel, Reiner; Savcenko, Roman; Bosch, Wolfgang; Skachko, Sergey; Danilov, Sergey

    2018-05-01

    General ocean circulation models are not perfect. Forced with observed atmospheric fluxes they gradually drift away from measured distributions of temperature and salinity. We suggest data assimilation of absolute dynamical ocean topography (DOT) observed from space geodetic missions as an option to reduce these differences. Sea surface information of DOT is transferred into the deep ocean by defining the analysed ocean state as a weighted average of an ensemble of fully consistent model solutions using an error-subspace ensemble Kalman filter technique. Success of the technique is demonstrated by assimilation into a global configuration of the ocean circulation model FESOM over 1 year. The dynamic ocean topography data are obtained from a combination of multi-satellite altimetry and geoid measurements. The assimilation result is assessed using independent temperature and salinity analysis derived from profiling buoys of the AGRO float data set. The largest impact of the assimilation occurs at the first few analysis steps where both the model ocean topography and the steric height (i.e. temperature and salinity) are improved. The continued data assimilation over 1 year further improves the model state gradually. Deep ocean fields quickly adjust in a sustained manner: A model forecast initialized from the model state estimated by the data assimilation after only 1 month shows that improvements induced by the data assimilation remain in the model state for a long time. Even after 11 months, the modelled ocean topography and temperature fields show smaller errors than the model forecast without any data assimilation.

  1. Assessing Bioinspired Topographies for their Antifouling Potential Control Using Computational Fluid Dynamics (CFD

    Directory of Open Access Journals (Sweden)

    Ling Jacky

    2018-01-01

    Full Text Available Biofouling is the accumulation of unwanted material on surfaces submerged or semi submerged over an extended period. This study investigates the antifouling performance of a new bioinspired topography design. A shark riblets inspired topography was designed with Solidworks and CFD simulations were antifouling performance. The study focuses on the fluid flow velocity, the wall shear stress and the appearance of vortices are to be noted to determine the possible locations biofouling would most probably occur. The inlet mass flow rate is 0.01 kgs-1 and a no-slip boundary condition was applied to the walls of the fluid domain. Simulations indicate that Velocity around the topography averaged at 7.213 x 10-3 ms-1. However, vortices were observed between the gaps. High wall shear stress is observed at the peak of each topography. In contrast, wall shear stress is significantly low at the bed of the topography. This suggests the potential location for the accumulation of biofouling. Results show that bioinspired antifouling topography can be improved by reducing the frequency of gaps between features. Linear surfaces on the topography should also be minimized. This increases the avenues of flow for the fluid, thus potentially increasing shear stresses with surrounding fluid leading to better antifouling performance.

  2. Modelling Earth's surface topography: decomposition of the static and dynamic components

    DEFF Research Database (Denmark)

    Guerri, Mattia; Cammarano, Fabio; Tackley, Paul J.

    2016-01-01

    . We account for pressure, temperature and compositional effects as inferred by mineral physics to relate seismic velocity with density. Mantle density models are coupled to crustal density distributions obtained with a similar methodology. We compute isostatic topography and associated residual...

  3. An investigation of ozone and planetary boundary layer dynamics over the complex topography of Grenoble combining measurements and modeling

    OpenAIRE

    Couach , O.; Balin , I.; Jiménez , R.; Ristori , P.; Perego , S.; Kirchner , F.; Simeonov , V.; Calpini , B.; Van Den Bergh , H.

    2003-01-01

    This paper concerns an evaluation of ozone (O3) and planetary boundary layer (PBL) dynamics over the complex topography of the Grenoble region through a combination of measurements and mesoscale model (METPHOMOD) predictions for three days, during July 1999. The measurements of O3 and PBL structure were obtained with a Differential Absorption Lidar (DIAL) system, situated 20 km south of Grenoble at Vif (310 m ASL). The combined lidar observations ...

  4. SLAM - Based Approach to Dynamic Ship Positioning

    Directory of Open Access Journals (Sweden)

    Krzysztof Wrobel

    2014-03-01

    Full Text Available Dynamically positioned vessels, used by offshore industry, use not only satellite navigation but also different positioning systems, often referred to as reference' systems. Most of them use multiple technical devices located outside the vessel which creates some problems with their accessibility and performance. In this paper, a basic concept of reference system independent from any external device is presented, basing on hydroacoustics and Simultaneous Localization and Mapping (SLAM method. Theoretical analysis of its operability is also performed.

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    Mario A Pardo

    Full Text Available 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

  7. Topography on a subcellular scale modulates cellular adhesions and actin stress fiber dynamics in tumor associated fibroblasts

    Science.gov (United States)

    Azatov, Mikheil; Sun, Xiaoyu; Suberi, Alexandra; Fourkas, John T.; Upadhyaya, Arpita

    2017-12-01

    Cells can sense and adapt to mechanical properties of their environment. The local geometry of the extracellular matrix, such as its topography, has been shown to modulate cell morphology, migration, and proliferation. Here we investigate the effect of micro/nanotopography on the morphology and cytoskeletal dynamics of human pancreatic tumor-associated fibroblast cells (TAFs). We use arrays of parallel nanoridges with variable spacings on a subcellular scale to investigate the response of TAFs to the topography of their environment. We find that cell shape and stress fiber organization both align along the direction of the nanoridges. Our analysis reveals a strong bimodal relationship between the degree of alignment and the spacing of the nanoridges. Furthermore, focal adhesions align along ridges and form preferentially on top of the ridges. Tracking actin stress fiber movement reveals enhanced dynamics of stress fibers on topographically patterned surfaces. We find that components of the actin cytoskeleton move preferentially along the ridges with a significantly higher velocity along the ridges than on a flat surface. Our results suggest that a complex interplay between the actin cytoskeleton and focal adhesions coordinates the cellular response to micro/nanotopography.

  8. Errors of Mean Dynamic Topography and Geostrophic Current Estimates in China's Marginal Seas from GOCE and Satellite Altimetry

    DEFF Research Database (Denmark)

    Jin, Shuanggen; Feng, Guiping; Andersen, Ole Baltazar

    2014-01-01

    and geostrophic current estimates from satellite gravimetry and altimetry are investigated and evaluated in China's marginal seas. The cumulative error in MDT from GOCE is reduced from 22.75 to 9.89 cm when compared to the Gravity Recovery and Climate Experiment (GRACE) gravity field model ITG-Grace2010 results......The Gravity Field and Steady-State Ocean Circulation Explorer (GOCE) and satellite altimetry can provide very detailed and accurate estimates of the mean dynamic topography (MDT) and geostrophic currents in China's marginal seas, such as, the newest high-resolution GOCE gravity field model GO......-CONS-GCF-2-TIM-R4 and the new Centre National d'Etudes Spatiales mean sea surface model MSS_CNES_CLS_11 from satellite altimetry. However, errors and uncertainties of MDT and geostrophic current estimates from satellite observations are not generally quantified. In this paper, errors and uncertainties of MDT...

  9. A global mean ocean circulation estimation using goce gravity models - the DTU12MDT mean dynamic topography model

    DEFF Research Database (Denmark)

    Knudsen, Per; Andersen, Ole Baltazar

    2012-01-01

    The Gravity and Ocean Circulation Experiment - GOCE satellite mission measure the Earth gravity field with unprecedented accuracy leading to substantial improvements in the modelling of the ocean circulation and transport. In this study of the performance of GOCE, a newer gravity model have been...... combined with the DTU10MSS mean sea surface model to construct a global mean dynamic topography model named DTU10MDT. The results of preliminary analyses using preliminary GOCE gravity models clearly demonstrated the potential of GOCE mission. Both the resolution and the estimation of the surface currents...... have been improved significantly compared to results obtained using pre-GOCE gravity field models. The results of this study show that geostrophic surface currents associated with the mean circulation have been further improved and that currents having speeds down to 5 cm/s have been recovered....

  10. Real-time positioning in logging: Effects of forest stand characteristics, topography, and line-of-sight obstructions on GNSS-RF transponder accuracy and radio signal propagation.

    Directory of Open Access Journals (Sweden)

    Eloise G Zimbelman

    Full Text Available Real-time positioning on mobile devices using global navigation satellite system (GNSS technology paired with radio frequency (RF transmission (GNSS-RF may help to improve safety on logging operations by increasing situational awareness. However, GNSS positional accuracy for ground workers in motion may be reduced by multipath error, satellite signal obstruction, or other factors. Radio propagation of GNSS locations may also be impacted due to line-of-sight (LOS obstruction in remote, forested areas. The objective of this study was to characterize the effects of forest stand characteristics, topography, and other LOS obstructions on the GNSS accuracy and radio signal propagation quality of multiple Raveon Atlas PT GNSS-RF transponders functioning as a network in a range of forest conditions. Because most previous research with GNSS in forestry has focused on stationary units, we chose to analyze units in motion by evaluating the time-to-signal accuracy of geofence crossings in 21 randomly-selected stands on the University of Idaho Experimental Forest. Specifically, we studied the effects of forest stand characteristics, topography, and LOS obstructions on (1 the odds of missed GNSS-RF signals, (2 the root mean squared error (RMSE of Atlas PTs, and (3 the time-to-signal accuracy of safety geofence crossings in forested environments. Mixed-effects models used to analyze the data showed that stand characteristics, topography, and obstructions in the LOS affected the odds of missed radio signals while stand variables alone affected RMSE. Both stand characteristics and topography affected the accuracy of geofence alerts.

  11. Real-time positioning in logging: Effects of forest stand characteristics, topography, and line-of-sight obstructions on GNSS-RF transponder accuracy and radio signal propagation.

    Science.gov (United States)

    Zimbelman, Eloise G; Keefe, Robert F

    2018-01-01

    Real-time positioning on mobile devices using global navigation satellite system (GNSS) technology paired with radio frequency (RF) transmission (GNSS-RF) may help to improve safety on logging operations by increasing situational awareness. However, GNSS positional accuracy for ground workers in motion may be reduced by multipath error, satellite signal obstruction, or other factors. Radio propagation of GNSS locations may also be impacted due to line-of-sight (LOS) obstruction in remote, forested areas. The objective of this study was to characterize the effects of forest stand characteristics, topography, and other LOS obstructions on the GNSS accuracy and radio signal propagation quality of multiple Raveon Atlas PT GNSS-RF transponders functioning as a network in a range of forest conditions. Because most previous research with GNSS in forestry has focused on stationary units, we chose to analyze units in motion by evaluating the time-to-signal accuracy of geofence crossings in 21 randomly-selected stands on the University of Idaho Experimental Forest. Specifically, we studied the effects of forest stand characteristics, topography, and LOS obstructions on (1) the odds of missed GNSS-RF signals, (2) the root mean squared error (RMSE) of Atlas PTs, and (3) the time-to-signal accuracy of safety geofence crossings in forested environments. Mixed-effects models used to analyze the data showed that stand characteristics, topography, and obstructions in the LOS affected the odds of missed radio signals while stand variables alone affected RMSE. Both stand characteristics and topography affected the accuracy of geofence alerts.

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

    Science.gov (United States)

    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.

  13. Future Antarctic bed topography and its implications for ice sheet dynamics

    Science.gov (United States)

    Adhikari, S.; Ivins, E. R.; Larour, E.; Seroussi, H.; Morlighem, M.; Nowicki, S.

    2014-06-01

    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 45 mm yr-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.

  14. Topography Grid

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NGDC builds and distributes high-resolution, coastal digital elevation models (DEMs) that integrate ocean bathymetry and land topography to support NOAA's mission to...

  15. The Influence of Topography on the Emplacement Dynamics of Martian Lava flows

    Science.gov (United States)

    Tremblay, J.; Fitch, E. P.; Fagents, S. A.

    2017-12-01

    Lava flows on the Martian surface exhibit a diverse array of complex morphologies. Previous emplacement models, based on terrestrial flows, do not fully account for these observed complex morphologies. We assert that the topography encountered by the flow can exert substantial control over the thermal, rheological, and morphological evolution of the flow, and that these effects can be better incorporated into flow models to predict Martian flow morphologies. Our development of an updated model can be used to account for these topographical effects and better constrain flow parameters. The model predicts that a slope break or flow meander induces eddy currents within the flow, resulting in the disruption of the flow surface crust. The exposure of the flow core results in accelerated cooling of the flow and a resultant increase in viscosity, leading to slowing of the flow. A constant source lava flux and a stagnated flow channel would then result in observable morphological changes, such as overflowing of channel levees. We have identified five morphological types of Martian flows, representing a range of effusion rates, eruption durations and topographic settings, which are suitable for application of our model. To characterize flow morphology, we used imaging and topographic data sets to collect data on flow dimensions. For eight large (50 to hundreds of km long) channelized flows in the Tharsis region, we used the MOLA 128 ppd DEM and/or individual MOLA shot points to derive flow cross-sectional thickness profiles, from which we calculated the cross-sectional area of the flow margins adjacent to the main channel. We found that the largest flow margin cross sectional areas (excluding the channel) occur in association with a channel bend, typically near the bend apex. Analysis of high-resolution images indicates that these widened flow margins are the result of repeated overflows of the channel levees and emplacement of short flow lobes adjacent to the main flow. In

  16. The influence of the surface topography on the magnetization dynamics in soft magnetic thin films

    NARCIS (Netherlands)

    Craus, CB; Palasantzas, G; Chezan, AR; De Hosson, JTM; Boerma, DO; Niesen, L

    2005-01-01

    In this work we study the influence of surface roughness on the magnetization dynamics of soft magnetic nanocrystalline Fe-Zr-N thin films deposited (under identical conditions) onto a Si oxide, a thin polymer layer, and a thin Cu layer. The substrate temperature during deposition was approximately

  17. Modeling of metal thin film growth: Linking angstrom-scale molecular dynamics results to micron-scale film topographies

    Science.gov (United States)

    Hansen, U.; Rodgers, S.; Jensen, K. F.

    2000-07-01

    A general method for modeling ionized physical vapor deposition is presented. As an example, the method is applied to growth of an aluminum film in the presence of an ionized argon flux. Molecular dynamics techniques are used to examine the surface adsorption, reflection, and sputter reactions taking place during ionized physical vapor deposition. We predict their relative probabilities and discuss their dependence on energy and incident angle. Subsequently, we combine the information obtained from molecular dynamics with a line of sight transport model in a two-dimensional feature, incorporating all effects of reemission and resputtering. This provides a complete growth rate model that allows inclusion of energy- and angular-dependent reaction rates. Finally, a level-set approach is used to describe the morphology of the growing film. We thus arrive at a computationally highly efficient and accurate scheme to model the growth of thin films. We demonstrate the capabilities of the model predicting the major differences on Al film topographies between conventional and ionized sputter deposition techniques studying thin film growth under ionized physical vapor deposition conditions with different Ar fluxes.

  18. Theoretical evaluation of accuracy in position and size of brain activity obtained by near-infrared topography

    International Nuclear Information System (INIS)

    Kawaguchi, Hiroshi; Hayashi, Toshiyuki; Kato, Toshinori; Okada, Eiji

    2004-01-01

    Near-infrared (NIR) topography can obtain a topographical distribution of the activated region in the brain cortex. Near-infrared light is strongly scattered in the head, and the volume of tissue sampled by a source-detector pair on the head surface is broadly distributed in the brain. This scattering effect results in poor resolution and contrast in the topographic image of the brain activity. In this study, a one-dimensional distribution of absorption change in a head model is calculated by mapping and reconstruction methods to evaluate the effect of the image reconstruction algorithm and the interval of measurement points for topographic imaging on the accuracy of the topographic image. The light propagation in the head model is predicted by Monte Carlo simulation to obtain the spatial sensitivity profile for a source-detector pair. The measurement points are one-dimensionally arranged on the surface of the model, and the distance between adjacent measurement points is varied from 4 mm to 28 mm. Small intervals of the measurement points improve the topographic image calculated by both the mapping and reconstruction methods. In the conventional mapping method, the limit of the spatial resolution depends upon the interval of the measurement points and spatial sensitivity profile for source-detector pairs. The reconstruction method has advantages over the mapping method which improve the results of one-dimensional analysis when the interval of measurement points is less than 12 mm. The effect of overlapping of spatial sensitivity profiles indicates that the reconstruction method may be effective to improve the spatial resolution of a two-dimensional reconstruction of topographic image obtained with larger interval of measurement points. Near-infrared topography with the reconstruction method potentially obtains an accurate distribution of absorption change in the brain even if the size of absorption change is less than 10 mm

  19. Positive dynamical systems in discrete time theory, models, and applications

    CERN Document Server

    Krause, Ulrich

    2015-01-01

    This book provides a systematic, rigorous and self-contained treatment of positive dynamical systems. A dynamical system is positive when all relevant variables of a systemare nonnegative in a natural way. This is in biology, demography or economics, where the levels of populations or prices of goods are positive. The principle also finds application in electrical engineering, physics and computer sciences.

  20. Mining the topography and dynamics of the 4D Nucleome to identify novel CNS drug pathways.

    Science.gov (United States)

    Higgins, Gerald A; Allyn-Feuer, Ari; Georgoff, Patrick; Nikolian, Vahagn; Alam, Hasan B; Athey, Brian D

    2017-07-01

    The pharmacoepigenome can be defined as the active, noncoding province of the genome including canonical spatial and temporal regulatory mechanisms of gene regulation that respond to xenobiotic stimuli. Many psychotropic drugs that have been in clinical use for decades have ill-defined mechanisms of action that are beginning to be resolved as we understand the transcriptional hierarchy and dynamics of the nucleus. In this review, we describe spatial, temporal and biomechanical mechanisms mediated by psychotropic medications. Focus is placed on a bioinformatics pipeline that can be used both for detection of pharmacoepigenomic variants that discretize drug response and adverse events to improve pharmacogenomic testing, and for the discovery of novel CNS therapeutics. This approach integrates the functional topology and dynamics of the transcriptional hierarchy of the pharmacoepigenome, gene variant-driven identification of pharmacogenomic regulatory domains, and mesoscale mapping for the discovery of novel CNS pharmacodynamic pathways in human brain. Examples of the application of this pipeline are provided, including the discovery of valproic acid (VPA) mediated transcriptional reprogramming of neuronal cell fate following injury, and mapping of a CNS pathway glutamatergic pathway for the mood stabilizer lithium. These examples in regulatory pharmacoepigenomics illustrate how ongoing research using the 4D nucleome provides a foundation to further insight into previously unrecognized psychotropic drug pharmacodynamic pathways in the human CNS. Copyright © 2017. Published by Elsevier Inc.

  1. An investigation of ozone and planetary boundary layer dynamics over the complex topography of Grenoble combining measurements and modeling

    Directory of Open Access Journals (Sweden)

    O. Couach

    2003-01-01

    Full Text Available This paper concerns an evaluation of ozone (O3 and planetary boundary layer (PBL dynamics over the complex topography of the Grenoble region through a combination of measurements and mesoscale model (METPHOMOD predictions for three days, during July 1999. The measurements of O3 and PBL structure were obtained with a Differential Absorption Lidar (DIAL system, situated 20 km south of Grenoble at Vif (310 m ASL. The combined lidar observations and model calculations are in good agreement with atmospheric measurements obtained with an instrumented aircraft (METAIR. Ozone fluxes were calculated using lidar measurements of ozone vertical profiles concentrations and the horizontal wind speeds measured with a Radar Doppler wind profiler (DEGREANE. The ozone flux patterns indicate that the diurnal cycle of ozone production is controlled by local thermal winds. The convective PBL maximum height was some 2700 m above the land surface while the nighttime residual ozone layer was generally found between 1200 and 2200 m. Finally we evaluate the magnitude of the ozone processes at different altitudes in order to estimate the photochemical ozone production due to the primary pollutants emissions of Grenoble city and the regional network of automobile traffic.

  2. Comparison between geodetic and oceanographic approaches to estimate mean dynamic topography for vertical datum unification: evaluation at Australian tide gauges

    Science.gov (United States)

    Filmer, M. S.; Hughes, C. W.; Woodworth, P. L.; Featherstone, W. E.; Bingham, R. J.

    2018-04-01

    The direct method of vertical datum unification requires estimates of the ocean's mean dynamic topography (MDT) at tide gauges, which can be sourced from either geodetic or oceanographic approaches. To assess the suitability of different types of MDT for this purpose, we evaluate 13 physics-based numerical ocean models and six MDTs computed from observed geodetic and/or ocean data at 32 tide gauges around the Australian coast. We focus on the viability of numerical ocean models for vertical datum unification, classifying the 13 ocean models used as either independent (do not contain assimilated geodetic data) or non-independent (do contain assimilated geodetic data). We find that the independent and non-independent ocean models deliver similar results. Maximum differences among ocean models and geodetic MDTs reach >150 mm at several Australian tide gauges and are considered anomalous at the 99% confidence level. These differences appear to be of geodetic origin, but without additional independent information, or formal error estimates for each model, some of these errors remain inseparable. Our results imply that some ocean models have standard deviations of differences with other MDTs (using geodetic and/or ocean observations) at Australian tide gauges, and with levelling between some Australian tide gauges, of ˜ ± 50 mm . This indicates that they should be considered as an alternative to geodetic MDTs for the direct unification of vertical datums. They can also be used as diagnostics for errors in geodetic MDT in coastal zones, but the inseparability problem remains, where the error cannot be discriminated between the geoid model or altimeter-derived mean sea surface.

  3. Using high resolution aridity and drainage position data to better predict rainfall-runoff relationships in complex upland topography

    Science.gov (United States)

    Metzen, D.; Sheridan, G. J.; Benyon, R. G.; Lane, P. N. J.

    2015-12-01

    In topographically complex terrain, the interaction of aspect-dependent solar exposure and drainage-position-dependent flow accumulation results in energy and water partitioning that is highly spatially variable. Catchment scale rainfall-runoff relationships are dependent on these smaller scale spatial patterns. However, there remains considerable uncertainty as to how to represent this smaller scale variability within lumped parameter, catchment scale rainfall-runoff models. In this study we aim to measure and represent the key interactions between aridity and drainage position in complex terrain to inform the development of simple catchment-scale hydrologic model parameters. Six measurement plots were setup on opposing slopes in an east-west facing eucalypt forest headwater catchment. The field sites are spanning three drainage positions with two contrasting aridity indices each, while minimizing variations in other factors, e.g. geology and weather patterns. Sapflow, soil water content (SWC) and throughfall were continuously monitored on two convergent hillslopes with similar size (1.3 and 1.6ha) but contrasting aspects (north and south). Soil depth varied from 0.6m at the topslope to >2m at the bottomslope positions. Maximum tree heights ranged from 16.2m to 36.9m on the equator-facing slope and from 30.1m to 45.5m on the pole-facing slope, with height decreasing upslope on both aspects. Two evapotranspiration (ET) patterns emerged in relation to aridity and drainage position. On the equator-facing slope (AI~ 2.1), seasonal understorey and overstorey ET patterns were in sync, whereas on the pole-facing slope (AI~1.5) understorey ET showed larger seasonal fluctuations than overstorey ET. Seasonal ET patterns and competition between soil evaporation and root water uptake lead to distinct differences in profile SWC across the sites, likely caused by depletion from different depths. Topsoil water content on equator-facing slopes was generally lower and responded

  4. On the Relationship of Dynamic Forearc Processes in Southern Peru to the Development and Preservation of Andean Topography

    Science.gov (United States)

    Hall, S. R.; Farber, D. L.; Audin, L.; Saillard, M.; Finkel, R. C.

    2008-12-01

    After more than 40 years of study, the timing and nature of Andean uplift remains an area of great scientific debate. The forearc of the Andean margin is of particular neotectonic interest, as previous models of Andean orogenesis attributed little-no Neogene deformation to the western margin of Altiplano. However, using the combination of remote sensing with high-resolution data, in situ cosmogenic isotope concentrations and thermochronology, in recent years the community has made important advances in addressing the rates, timings, styles, and locations of active deformation within the forearc of the Andean margin. To first order, we find that - both in terms of tectonics and climate - since 10Ma, the Andean forearc has been quite a dynamic region. Neotectonic studies in this region have been facilitated by the high degree of geomorphic surface preservation that the hyperarid (for at least the last 3My) coastal Atacama Desert has provided. Specifically, in southern Peru (14°-18°S), vast pediment surfaces have been abandoned through incision along the major river drainages that carve the deep canyons into the Precordillera and Western Cordillera. While the exact timing of the periods of more intense incision plausibly correspond with climate events, the total amount of incision integrated over many climate cycles is a useful indicator of tectonic activity. In this region, we find a number of geomorphic and structural features that provide strong evidence for distributed crustal deformation along range-sub-parallel contractile and strike-slip structures. Specifically, we see 1) ancient surfaces reflecting erosion rates as low as chronologies, and 6) Pleistocene mass-wasting events accommodating the redistribution of ~109-1010 m3 of material per event. Furthermore, the observation that Pleistocene incision rates are comparable with Late Miocene and Pliocene rates, suggests to us, that the rates and style of surface uplift within the forearc of southern Peru has

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

    DEFF Research Database (Denmark)

    Schiffer, Christian; Nielsen, Søren Bom

    2016-01-01

    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 wel...

  6. Dynamic Positioning of Ships : A nonlinear control design study

    NARCIS (Netherlands)

    Muhammad, S.

    2012-01-01

    Dynamic positioning (DP) is relatively a new technique used to maintain the position and heading of ships in various offshore operations. Due to the features like better safety and operating efficiency, DP systems are becoming more and more popular. This thesis mainly focusses on the control system

  7. An intelligent operator support system for dynamic positioning

    NARCIS (Netherlands)

    Diggelen, J. van; Broek, J. van den; Schraagen, J.M.C.; Waa, J.S. van der

    2018-01-01

    This paper proposes a human-centered approach to Dynamic Position-ing systems which combines multiple technologies in an intelligent operator sup-port system (IOSS). IOSS allows the operator to be roaming and do other tasks in quiet conditions. When conditions become more demanding, the IOSS calls

  8. Positive Affect and the Complex Dynamics of Human Flourishing

    Science.gov (United States)

    Fredrickson, Barbara L.; Losada, Marcial F.

    2005-01-01

    Extending B. L. Fredrickson's (1998) broaden-and-build theory of positive emotions and M. Losada's (1999) nonlinear dynamics model of team performance, the authors predict that a ratio of positive to negative affect at or above 2.9 will characterize individuals in flourishing mental health. Participants (N=188) completed an initial survey to…

  9. Positive Affect and the Complex Dynamics of Human Flourishing

    OpenAIRE

    Fredrickson, Barbara L.; Losada, Marcial F.

    2005-01-01

    Extending B. L. Fredrickson’s (1998) broaden-and-build theory of positive emotions and M. Losada’s (1999) nonlinear dynamics model of team performance, the authors predict that a ratio of positive to negative affect at or above 2.9 will characterize individuals in flourishing mental health. Participants (N = 188) completed an initial survey to identify flourishing mental health and then provided daily reports of experienced positive and negative emotions over 28 days. Results showed that the ...

  10. Use of recent geoid models to estimate mean dynamic topography and geostrophic currents in South Atlantic and Brazil Malvinas confluence

    Directory of Open Access Journals (Sweden)

    Alexandre Bernardino Lopes

    2012-03-01

    Full Text Available The use of geoid models to estimate the Mean Dynamic Topography was stimulated with the launching of the GRACE satellite system, since its models present unprecedented precision and space-time resolution. In the present study, besides the DNSC08 mean sea level model, the following geoid models were used with the objective of computing the MDTs: EGM96, EIGEN-5C and EGM2008. In the method adopted, geostrophic currents for the South Atlantic were computed based on the MDTs. In this study it was found that the degree and order of the geoid models affect the determination of TDM and currents directly. The presence of noise in the MDT requires the use of efficient filtering techniques, such as the filter based on Singular Spectrum Analysis, which presents significant advantages in relation to conventional filters. Geostrophic currents resulting from geoid models were compared with the HYCOM hydrodynamic numerical model. In conclusion, results show that MDTs and respective geostrophic currents calculated with EIGEN-5C and EGM2008 models are similar to the results of the numerical model, especially regarding the main large scale features such as boundary currents and the retroflection at the Brazil-Malvinas Confluence.A utilização de modelos geoidais na determinação da Topografia Dinâmica Média foi impulsionada com o lançamento dos satélites do sistema GRACE, já que seus modelos apresentam precisão e resolução espacial e temporal sem precedentes. No presente trabalho, além do modelo de nível médio do mar DNSC08, foram utilizados os seguintes modelos geoidais com o objetivo de calcular as TDMs: EGM96, EIGEN-5C e EGM2008. No método adotado, foram calculadas as respectivas correntes geostróficas para o Atlântico Sul a partir das TDMs. O grau e ordem dos modelos geoidais influenciam diretamente na determinação da TDM e correntes. Neste trabalho verificou-se que presença de ruídos da TDM requer a utilização de técnicas de filtragem

  11. Dynamical black rings with a positive cosmological constant

    International Nuclear Information System (INIS)

    Kimura, Masashi

    2009-01-01

    We construct dynamical black ring solutions in the five-dimensional Einstein-Maxwell system with a positive cosmological constant and investigate the geometrical structure. The solutions describe the physical process such that a thin black ring at early time shrinks and changes into a single black hole as time increases. We also discuss the multiblack rings and the coalescence of them.

  12. Does Dynamical Downscaling Introduce Novel Information in Climate Model Simulations of Recipitation Change over a Complex Topography Region?

    Science.gov (United States)

    Tselioudis, George; Douvis, Costas; Zerefos, Christos

    2012-01-01

    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 topography regions, GCM predictions of precipitation change with climate warming may be dry biased due to the GCM smoothing of the regional topography.

  13. Comparative study on findings of the brain computed tomography (X-ray-CT) and dynamic topography of VEP (VDT)

    International Nuclear Information System (INIS)

    Matsuura, Masashi

    1985-01-01

    Comparative study between morphological Xray-CT and functional VDT was conducted on 20 cases of cerebral diseases with visual dysfunction. Subjects were patients with cerebral infarction, intracranial hemorrhage, hemispherectomy, traumatic brain atrophy, brain tumor, Creutzfeldt-Jakob disease, anoxic encephalopathy, porencephaly, microcephaly and optic tract lesion. VEP topography was performed by flash stimulation and brain electrical activity mappings were displayed by EEG topography computer. In 9 cases out of 20, abolished function in VDT was correlated to the defective findings of Xray-CT. Cases with homonymous hemianopsia showed 2 types of BEAM. In cases with a lesion in the inner surface of the occipital lobe, asymmetric electric activity was distributed along the sagittal axis of the scalp. While, in cases with outer surface lesion of the occipital lobe, asymmetric electric activity appeared along the coronary axis. In cases with multi focal brain lesions in Xray-CT, there was no regular tendency in abnormality of VDT. Various aberration of VEP and VDT, such as component defect, stagnation, reduction, condensation and abnormal flow were demonstrated. In a case of optic tract lesion, Xray-CT showed no pathological findings but VDT showed a remarkable asymmetry of brain activity. (author)

  14. Flat Top Barge 300 feet Using Portable Dynamic Positioning System

    Directory of Open Access Journals (Sweden)

    Agoes Santoso

    2017-03-01

    Full Text Available Portable Dynamic Positioning System has not commonly applied to the ship, especially on barge. Besides for Dynamic Positioning function, the system can be used as ship's main propulsion. By using this system, the ship able to not using anchors because the functions can be performed by the Portable Dynamic System. Therefore, research about the application of Portable Dynamic Positioning System on the ship is conducted. This research aims to design a Flat Top Barge 300feet ship, to determine the specifications of Portable Dynamic Positioning System which is used, and to find out the ship stability which is designed on the empty payload condition and maximum payload. This research designed the ships with main dimensions LWL 90.1 meters, 25 meters wide, 5.5 meters high and 4.2 meters draught. To generate the ship with a maximum speed of 8 knots, it takes four thruster supplied with power 225 kW each, so that the total generated power is 1100 kW. This study analyzes three conditions of the ship stability, there are the condition of full payload, empty payload, and maximum payload. Each payload conditions will be analyzed regarding the large payload and draught water produced. The first is full payload conditions resulting payload in the amount of 5650 ton with a draught on the LCF at 4,181 meters. The second is the large empty payload condition displacement is 2809 ton and water draught on the LCF at 1,591. And the last is maximum payload conditions, resulting payload in the amount of 7450 ton with a draught on the LCF at 4,994 meters.

  15. Flow Around Steep Topography

    Science.gov (United States)

    2015-09-30

    Flow around steep topography T. M. Shaun Johnston Scripps Institution of Oceanography University of California, San Diego 9500 Gilman Drive, M...tall, steep, submarine topography and islands. During the Flow Encountering Abrupt Topography (FLEAT) DRI, investigators will determine: • Whether...estimates from making accurate statistical/deterministic predictions at ᝺ km resolution around submarine topography and islands? How can we

  16. Hamiltonian Dynamics and Positive Energy in General Relativity

    Energy Technology Data Exchange (ETDEWEB)

    Deser, S. [Physics Department, Brandeis University, Waltham, MA (United States)

    1969-07-15

    A review is first given of the Hamiltonian formulation of general relativity; the gravitational field is a self-interacting massless spin-two system within the framework of ordinary Lorentz covariant field theory. The recently solved problem of positive-definiteness of the field energy is then discussed. The latter, a conserved functional of the dynamical variables, is shown to have only one extremum, a local minimum, which is the vacuum state (flat space). This implies positive energy for the field, with the vacuum as ground-state. Similar results hold when minimally coupled matter is present. (author)

  17. The complex dynamics of wishful thinking: the critical positivity ratio.

    Science.gov (United States)

    Brown, Nicholas J L; Sokal, Alan D; Friedman, Harris L

    2013-12-01

    We examine critically the claims made by Fredrickson and Losada (2005) concerning the construct known as the "positivity ratio." We find no theoretical or empirical justification for the use of differential equations drawn from fluid dynamics, a subfield of physics, to describe changes in human emotions over time; furthermore, we demonstrate that the purported application of these equations contains numerous fundamental conceptual and mathematical errors. The lack of relevance of these equations and their incorrect application lead us to conclude that Fredrickson and Losada's claim to have demonstrated the existence of a critical minimum positivity ratio of 2.9013 is entirely unfounded. More generally, we urge future researchers to exercise caution in the use of advanced mathematical tools, such as nonlinear dynamics, and in particular to verify that the elementary conditions for their valid application have been met. PsycINFO Database Record (c) 2013 APA, all rights reserved.

  18. Ancrage dynamique: principales applications Dynamic Positioning: Main Applications

    Directory of Open Access Journals (Sweden)

    Fay H.

    2006-11-01

    Full Text Available L'ancrage dynamique est la technique qui a permis à la recherche pétrolière d'étendre ses possibilités bien au-delà des plateaux continentaux, sans limitation de profondeur, pour des opérations difficiles, ou encore dans un environnement océanométéorologique sévère, comme celui de la mer du Nord et des mers froides avec la présence d'icebergs. Cet article correspond à des extraits de l'ouvrage Ancrage dynamique. Technique et applications , à paraître aux Editions Technip. Après un bref rappel historique et un exposé succinct des caractéristiques des systèmes d'ancrage dynamique, les principales réalisations de navires et de plates-formes semi-submersibles équipées d'un ancrage dynamique sont présentées. La précision du maintien en position, ainsi que les limites opérationnelles des supports considérés sont de même exposées. Enfin la conclusion retrace les avantages de ce procédé, dont l'exceptionnel développement s'applique aussi aux domaines scientifiques et militaires, ainsi qu'à d'autres secteurs industriels que celui des hydrocarbures. Dynamic positioning is the technique that has enabled oil exploration to extend its possibilities far beyond continental shelves, without any limitation of water depth, for difficult operations or else in harsh environments such as for the North Sea and arctic zones with the presence of icebergs. This paper consists of extracts from the book Dynamic Positioning. Technique and Applications , to be published by Editions Technip. After a brief historical review and a succinct survey of the characteristics of dynamic positioning systems, the principal realizations of ships and semi-submersible platforms equipped with a dynamic positioning system are described. The accuracy of position holding capability as well as the operational limits of the supports considered are also described. The conclusion reviews the advantages of this technique, whose exceptional development also

  19. A million-plus neuron model of the hippocampal dentate gyrus: Dependency of spatio-temporal network dynamics on topography.

    Science.gov (United States)

    Hendrickson, Phillip J; Yu, Gene J; Song, Dong; Berger, Theodore W

    2015-01-01

    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: topography-dependent clusters of granule cell activity as "functional units" that organize the processing of entorhinal signals.

  20. Old and new technologies provide dynamic precise positioning

    International Nuclear Information System (INIS)

    Dano, P.K.

    1987-01-01

    Vehicle's coordinates are available for both reporting and operator use utilizing passive survey techniques and equipments with excellent results thus freeing up and protecting the vehicle reporting transmitters. Use of spread spectrum radiolocation offers real-time extraction and correction of system biases eliminating fixed timing errors. An unlimited number of users may receive differential signals as well as system description data in such a manner as to facilitate complete ''blind'' entry into the system while attaining full operational capability. Utilizing a proprietary technique, the passive user obtains additional lines of position as well as calibration information while using the traditional number of reference stations. A single frequency could be used world-wide since ''networks'' are identified by code. Adjacent networks can be indicated to the receiver using the system description data thus facilitating network to network operation without operator intervention. Although the system accuracy is excellent for survey, the automation of dynamic precise positioning is most advantageous in vehicle location

  1. Variations in calcite growth kinetics with surface topography: molecular dynamics simulations and process-based growth kinetics modelling

    NARCIS (Netherlands)

    Wolthers, M.; Di Tommaso, D.; Du, Zhimei; de Leeuw, Nora H.

    2013-01-01

    It is generally accepted that cation dehydration is the rate-limiting step to crystal growth from aqueous solution. Here we employ classical molecular dynamics simulations to show that the water exchange frequency at structurally distinct calcium sites in the calcite surface varies by about two

  2. Dynamic ocean topography from CryoSat-2: examining recent changes in ice-ocean stress and advancing a theory for Beaufort Gyre stabilization

    Science.gov (United States)

    Dewey, S.; Morison, J.; Kwok, R.; Dickinson, S.; Morison, D.; Andersen, R.

    2017-12-01

    Model and sparse observational evidence has shown the ocean current speed in the Beaufort Gyre to have increased and recently stabilized. However, full-basin altimetric observations of dynamic ocean topography (DOT) and ocean surface currents have yet to be applied to the dynamics of gyre stabilization. DOT fields from retracked CryoSat-2 retrievals in Arctic Ocean leads have enabled us to calculate 2-month average ocean geostrophic currents. These currents are crucial to accurately computing ice-ocean stress, especially because they have accelerated so that their speed rivals that of the overlying sea ice. Given these observations, we can shift our view of the Beaufort Gyre as a system in which the wind drives the ice and the ice drives a passive ocean to a system with the following feedback: After initial input of energy by wind, ice velocity decreases due to water drag and internal ice stress and the ocean drives the ice, reversing Ekman pumping and decelerating the gyre. This reversal changes the system from a persistently convergent regime to one in which freshwater is released from the gyre and doming of the gyre decreases, without any change in long-term average wind stress curl. Through these processes, the ice-ocean stress provides a key feedback in Beaufort Gyre stabilization.

  3. Research on Dynamic Parameters and Position Accuracy of Pneumatics Muscles

    Directory of Open Access Journals (Sweden)

    Edvard Sadovskij

    2012-12-01

    Full Text Available The article deals with pneumatic muscle MAS-20-200N-AA-MC-O, its dynamic properties and positioning accuracy as well as overviews experimental and theoretical works. The paper introduces the diagrams of vibration acceleration, discusses displacement dependence on pressure and load and presents a diagram of speed dependence on operating pressure. Vibroacceleration has been measured employing two accelerometers. Measurements have been carried out in three mutually perpendicular directions: x, y and z. The most important one is direction z, because this way the muscle performs a valuable displacement along the axis of the muscle, since this direction is the movement of the working muscle.Article in Lithuanian

  4. Research on Dynamic Parameters and Position Accuracy of Pneumatics Muscles

    Directory of Open Access Journals (Sweden)

    Edvard Sadovskij

    2013-02-01

    Full Text Available The article deals with pneumatic muscle MAS-20-200N-AA-MC-O, its dynamic properties and positioning accuracy as well as overviews experimental and theoretical works. The paper introduces the diagrams of vibration acceleration, discusses displacement dependence on pressure and load and presents a diagram of speed dependence on operating pressure. Vibroacceleration has been measured employing two accelerometers. Measurements have been carried out in three mutually perpendicular directions: x, y and z. The most important one is direction z, because this way the muscle performs a valuable displacement along the axis of the muscle, since this direction is the movement of the working muscle.Article in Lithuanian

  5. The dynamic origins of positive health and wellbeing

    Science.gov (United States)

    Cloninger, C. Robert; Salloum, Ihsan M.; Mezzich, Juan E.

    2015-01-01

    The causes of wellbeing and illbeing interact with feedback dynamics resulting in the same set of traits giving rise to a variety of health outcomes (multi-finality) and different traits giving rise to the same health outcome (equi-finality). As a result, a full understanding of health and its disorders must be in terms of a complex adaptive system of causes, rather than in terms of categorical diagnoses or sets of symptoms. The three domains of person-centered integrative diagnosis (PID) are considered here as interacting components of a complex adaptive system comprised of health status (functioning/wellness versus disability/disorder), experience of health (self-awareness/fulfillment versus misunderstanding/suffering) and contributors to health (protective versus risk factors). The PID domains thereby allow healthcare and health promotion to be understood in terms of measurable components of a complex adaptive system. Three major concepts of health are examined in detail to identify their dynamic origins: Psychological Maturity, Flourishing and Resilience. In humanistic psychology, psychological maturity (i.e. healthy personality, mental wellbeing) involves the development of high self-directedness, high co-operativeness and high self-transcendence, but self-transcendence is nevertheless devalued in individualistic and materialistic cultures except when people must face adversity and ultimate situations like suffering or the threat of death. Psychological Maturity develops through two complementary processes often labeled as Flourishing and Resilience. Flourishing is the development of one’s potential to live optimally, especially as the result of favorable circumstances, whereas Resilience is positive adaptation to life despite adverse circumstances. As a result of the complex feedback dynamics between the processes of flourishing and resilience, each person is a unique individual who has a variety of paths for achieving positive health and wellbeing open to

  6. The positive group affect spiral : a dynamic model of the emergence of positive affective similarity in work groups

    NARCIS (Netherlands)

    Walter, F.; Bruch, H.

    This conceptual paper seeks to clarify the process of the emergence of positive collective affect. Specifically, it develops a dynamic model of the emergence of positive affective similarity in work groups. It is suggested that positive group affective similarity and within-group relationship

  7. Impact of lithospheric rheology on surface topography

    Science.gov (United States)

    Liao, K.; Becker, T. W.

    2017-12-01

    The expression of mantle flow such as due to a buoyant plume as surface topography is a classical problem, yet the role of rheological complexities could benefit from further exploration. Here, we investigate the topographic expressions of mantle flow by means of numerical and analytical approaches. In numerical modeling, both conventional, free-slip and more realistic, stress-free boundary conditions are applied. For purely viscous rheology, a high viscosity lithosphere will lead to slight overestimates of topography for certain settings, which can be understood by effectively modified boundary conditions. Under stress-free conditions, numerical and analytical results show that the magnitude of dynamic topography decreases with increasing lithosphere thickness (L) and viscosity (ηL), as L-1 and ηL-3. The wavelength of dynamic topography increases linearly with L and (ηL/ ηM) 1/3. We also explore the time-dependent interactions of a rising plume with the lithosphere. For a layered lithosphere with a decoupling weak lower crust embedded between stronger upper crust and lithospheric mantle, dynamic topography increases with a thinner and weaker lower crust. The dynamic topography saturates when the decoupling viscosity is 3-4 orders lower than the viscosity of upper crust and lithospheric mantle. We further explore the role of visco-elastic and visco-elasto-plastic rheologies.

  8. Nonlinear dynamic positioning of ships with gain-scheduled wave filtering

    DEFF Research Database (Denmark)

    Torsetnes, Guttorm; Jouffroy, Jerome; Fossen, Thor I.

    This paper presents a globally contracting controller for regulation and dynamic positioning of ships, using only position measurements. For this purpose a globally contracting observer which reconstructs the unmeasured states is constructed. The observer produces accurate estimates of position...

  9. SECTION 6.2 SURFACE TOPOGRAPHY ANALYSIS

    DEFF Research Database (Denmark)

    Seah, M. P.; De Chiffre, Leonardo

    2005-01-01

    Surface physical analysis, i.e. topography characterisation, encompasses measurement, visualisation, and quantification. This is critical for both component form and for surface finish at macro-, micro- and nano-scales. The principal methods of surface topography measurement are stylus profilometry......, optical scanning techniques, and scanning probe microscopy (SPM). These methods, based on acquisition of topography data from point by point scans, give quantitative information of heights with respect to position. Based on a different approach, the so-called integral methods produce parameters...

  10. Determination of locational error associated with global positioning system (GPS) radio collars in relation to vegetation and topography in north-central New Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, K.; Biggs, J.; Fresquez, P.R.

    1997-02-01

    In 1996, a study was initiated to assess seasonal habitat use and movement patterns of Rocky Mountain elk (Cervus elaphus nelsoni) using global positioning system (GPS) radio collars. As part of this study, the authors attempted to assess the accuracies of GPS (non-differentially corrected) positions under various vegetation canopies and terrain conditions with the use of a GPS ``test`` collar. The test collar was activated every twenty minutes to obtain a position location and continuously uplinked to Argos satellites to transfer position data files. They used a Telonics, Inc. uplink receiver to intercept the transmission and view the results of the collar in real time. They placed the collar on a stand equivalent to the neck height of an adult elk and then placed the stand within three different treatment categories: (1) topographical influence (canyon and mesa tops), (2) canopy influence (open and closed canopy), and (3) vegetation type influence (ponderosa pine and pinion pine-juniper). The collar was kept at each location for one hour (usually obtaining three fixes). In addition, the authors used a hand-held GPS to obtain a position of the test collar at the same time and location.

  11. Positivity-preserving dual time stepping schemes for gas dynamics

    Science.gov (United States)

    Parent, Bernard

    2018-05-01

    A new approach at discretizing the temporal derivative of the Euler equations is here presented which can be used with dual time stepping. The temporal discretization stencil is derived along the lines of the Cauchy-Kowalevski procedure resulting in cross differences in spacetime but with some novel modifications which ensure the positivity of the discretization coefficients. It is then shown that the so-obtained spacetime cross differences result in changes to the wave speeds and can thus be incorporated within Roe or Steger-Warming schemes (with and without reconstruction-evolution) simply by altering the eigenvalues. The proposed approach is advantaged over alternatives in that it is positivity-preserving for the Euler equations. Further, it yields monotone solutions near discontinuities while exhibiting a truncation error in smooth regions less than the one of the second- or third-order accurate backward-difference-formula (BDF) for either small or large time steps. The high resolution and positivity preservation of the proposed discretization stencils are independent of the convergence acceleration technique which can be set to multigrid, preconditioning, Jacobian-free Newton-Krylov, block-implicit, etc. Thus, the current paper also offers the first implicit integration of the time-accurate Euler equations that is positivity-preserving in the strict sense (that is, the density and temperature are guaranteed to remain positive). This is in contrast to all previous positivity-preserving implicit methods which only guaranteed the positivity of the density, not of the temperature or pressure. Several stringent reacting and inert test cases confirm the positivity-preserving property of the proposed method as well as its higher resolution and higher computational efficiency over other second-order and third-order implicit temporal discretization strategies.

  12. A Numerical Study on Hydrodynamic Interactions between Dynamic Positioning Thrusters

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Doo Hwa; Lee, Sang Wook [University of Ulsan, Ulsan (Korea, Republic of)

    2017-06-15

    In this study, we conducted computational fluid dynamics (CFD) simulations for the unsteady hydrodynamic interaction of multiple thrusters by solving Reynolds averaged Navier-Stokes equations. A commercial CFD software, STAR-CCM+ was used for all simulations by employing a ducted thruster model with combination of a propeller and No. 19a duct. A sliding mesh technique was used to treat dynamic motion of propeller rotation and non-conformal hexahedral grid system was considered. Four different combinations in tilting and azimuth angles of the thrusters were considered to investigate the effects on the propulsion performance. We could find that thruster-hull and thruster-thruster interactions has significant effect on propulsion performance and further study will be required for the optimal configurations with the best tilting and relative azimuth angle between thrusters.

  13. Positive Nonlinear Dynamical Group Uniting Quantum Mechanics and Thermodynamics

    OpenAIRE

    Beretta, Gian Paolo

    2006-01-01

    We discuss and motivate the form of the generator of a nonlinear quantum dynamical group 'designed' so as to accomplish a unification of quantum mechanics (QM) and thermodynamics. We call this nonrelativistic theory Quantum Thermodynamics (QT). Its conceptual foundations differ from those of (von Neumann) quantum statistical mechanics (QSM) and (Jaynes) quantum information theory (QIT), but for thermodynamic equilibrium (TE) states it reduces to the same mathematics, and for zero entropy stat...

  14. 77 FR 62247 - Dynamic Positioning Operations Guidance for Vessels Other Than Mobile Offshore Drilling Units...

    Science.gov (United States)

    2012-10-12

    ... Operations Guidance for Vessels Other Than Mobile Offshore Drilling Units Operating on the U.S. Outer... ``Mobile Offshore Drilling Unit Dynamic Positioning Guidance''. The notice recommended owners and operators of Mobile Offshore Drilling Units (MODUs) follow Marine Technology Society (MTS) Dynamic Positioning...

  15. Topography. Ch. 10

    International Nuclear Information System (INIS)

    Chikawa, Jun-Ichi; Kuriyama, Masao

    1991-01-01

    The uniqueness of synchrotron X-ray topography does not lie in new theoretical or experimental notions about the topographic method, but in the characteristics of this new source as a critical optical element. At most synchrotron facilities, the spectrum ranging from 5 keV (2.5A) to 30 keV (0.4A0 can be made available for topography. A synchrotron-radiation source gives tunability (choice of wavelengths) and pulsed time structure with highly collimated an intense photon beams. The continuous spectrum and excellent collimation have made white-beam X-ray topography a practical reality. The high intensity of the synchrotron X-ray source, even after beam monochromatization and further collimation, permits time-dependent observation of kinetics. By selecting the mono-chromatized wavelength close to an absorption edge of an element in the sample crystal, the topographic data selectively emphasize or de-emphasize structures related to that element. For full use of such properties of synchrotron radiation, however, development of new optical systems and imaging detectors is required, and is in progress at most synchrotron facilities. This chapter covers a brief review of X-ray topography, its basic principles, and the necessary X-ray optical and imaging systems. The capability of synchrotron-radiation topography is demonstrated with some recent results. (author). 118 refs.; 22 figs

  16. X-ray topography and multiple diffraction

    International Nuclear Information System (INIS)

    Chang, S.-L.

    1983-01-01

    A short summary on X-ray topography, which is based on the dynamical theory of X-ray diffraction, is made. The applications and properties related to the use of the multiple diffraction technique are analized and discussed. (L.C.) [pt

  17. NONLINEAR FILTER METHOD OF GPS DYNAMIC POSITIONING BASED ON BANCROFT ALGORITHM

    Institute of Scientific and Technical Information of China (English)

    ZHANGQin; TAOBen-zao; ZHAOChao-ying; WANGLi

    2005-01-01

    Because of the ignored items after linearization, the extended Kalman filter (EKF) becomes a form of suboptimal gradient descent algorithm. The emanative tendency exists in GPS solution when the filter equations are ill-posed. The deviation in the estimation cannot be avoided. Furthermore, the true solution may be lost in pseudorange positioning because the linearized pseudorange equations are partial solutions. To solve the above problems in GPS dynamic positioning by using EKF, a closed-form Kalman filter method called the two-stage algorithm is presented for the nonlinear algebraic solution of GPS dynamic positioning based on the global nonlinear least squares closed algorithm--Bancroft numerical algorithm of American. The method separates the spatial parts from temporal parts during processing the GPS filter problems, and solves the nonlinear GPS dynamic positioning, thus getting stable and reliable dynamic positioning solutions.

  18. Kinetic theory for electron dynamics near a positive ion

    International Nuclear Information System (INIS)

    Wrighton, Jeffrey M; Dufty, James W

    2008-01-01

    A theoretical description of time correlation functions for electron properties in the presence of a positive ion of charge number Z is given. The simplest case of an electron gas distorted by a single ion is considered. A semi-classical representation with a regularized electron–ion potential is used to obtain a linear kinetic theory that is asymptotically exact at short times. This Markovian approximation includes all initial (equilibrium) electron–electron and electron–ion correlations through renormalized pair potentials. The kinetic theory is solved in terms of single-particle trajectories of the electron–ion potential and a dielectric function for the inhomogeneous electron gas. The results are illustrated by a calculation of the autocorrelation function for the electron field at the ion. The dependence on charge number Z is shown to be dominated by the bound states of the effective electron–ion potential. On this basis, a very simple practical representation of the trajectories is proposed and shown to be accurate over a wide range including strong electron–ion coupling. This simple representation is then used for a brief analysis of the dielectric function for the inhomogeneous electron gas

  19. Dynamics of positional warfare malaria: Finland and Korea compared.

    Science.gov (United States)

    Huldén, Lena; Huldén, Larry

    2008-09-08

    A sudden outbreak of vivax malaria among Finnish troops in SE-Finland and along the front line in Hanko peninsula in the southwest occurred in 1941 during World War II. The common explanation has been an invasion of infective Anopheles mosquitoes from the Russian troops crossing the front line between Finland and Soviet Union. A revised explanation is presented based on recent studies of Finnish malaria. The exact start of the epidemic and the phenology of malaria cases among the Finnish soldiers were reanalyzed. The results were compared with the declining malaria in Finland. A comparison with a corresponding situation starting in the 1990's in Korea was performed. The malaria cases occurred in July in 1941 when it was by far too early for infective mosquitoes to be present. The first Anopheles mosquitoes hatched at about the same time as the first malaria cases were observed among the Finnish soldiers. It takes about 3-6 weeks for the completion of the sporogony in Finland. The new explanation is that soldiers in war conditions were suddenly exposed to uninfected mosquitoes and those who still were carriers of hypnozoites developed relapses triggered by these mosquitoes. It is estimated that about 0.5% of the Finnish population still were carriers of hypnozoites in the 1940's. A corresponding outbreak of vivax malaria in Korea in the 1990's is similarly interpreted as relapses from activated hypnozoites among Korean soldiers. The significance of the mosquito induced relapses is emphasized by two benefits for the Plasmodium. There is a synchronous increase of gametocytes when new mosquitoes emerge. It also enables meiotic recombination between different strains of the Plasmodium. The malaria peak during the positional warfare in the 1940's was a short outbreak during the last phase of declining indigenous malaria in Finland. The activation of hypnozoites among a large number of soldiers and subsequent medication contributed to diminishing the reservoir of malaria

  20. Dynamic berth and quay crane allocation for multiple berth positions and quay cranes

    NARCIS (Netherlands)

    Tri Cahyono, Rully; Flonk, E.J.; Jayawardhana, Bayu

    2015-01-01

    We study in this paper a dynamic berth and quay cranes allocation strategy in general seaport container terminals. We develop a dynamical model that describes the operation of berthing process with multiple discrete berthing positions and multiple quay cranes. Based on the proposed model, we develop

  1. Adaptive wave filtering for dynamic positioning of marine vessels using maximum likelihood identification: Theory and experiments

    Digital Repository Service at National Institute of Oceanography (India)

    Hassani, V.; Sorensen, A.J.; Pascoal, A.M.

    This paper addresses a filtering problem that arises in the design of dynamic positioning systems for ships and offshore rigs subjected to the influence of sea waves. The dynamic model of the vessel captures explicitly the sea state as an uncertain...

  2. The Dawn Topography Investigation

    Science.gov (United States)

    Raymond, C. A.; Jaumann, R.; Nathues, A.; Sierks, H.; Roatsch, T.; Preusker, E; Scholten, F.; Gaskell, R. W.; Jorda, L.; Keller, H.-U.; hide

    2011-01-01

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

  3. Joining the pack or going solo? A dynamic theory of new firm positioning

    NARCIS (Netherlands)

    Boone, Chr.; Wezel, F.C.; van Witteloostuijn, A.

    2013-01-01

    The question of new firm positioning in the marketplace and entrant's subsequent long-term performance lies at the heart of strategic entrepreneurship. We suggest a dynamic theory of new firm positioning that hinges on an important feature of the competitive environment: industry-level product

  4. Design and reliability analysis of DP-3 dynamic positioning control architecture

    Science.gov (United States)

    Wang, Fang; Wan, Lei; Jiang, Da-Peng; Xu, Yu-Ru

    2011-12-01

    As the exploration and exploitation of oil and gas proliferate throughout deepwater area, the requirements on the reliability of dynamic positioning system become increasingly stringent. The control objective ensuring safety operation at deep water will not be met by a single controller for dynamic positioning. In order to increase the availability and reliability of dynamic positioning control system, the triple redundancy hardware and software control architectures were designed and developed according to the safe specifications of DP-3 classification notation for dynamically positioned ships and rigs. The hardware redundant configuration takes the form of triple-redundant hot standby configuration including three identical operator stations and three real-time control computers which connect each other through dual networks. The function of motion control and redundancy management of control computers were implemented by software on the real-time operating system VxWorks. The software realization of task loose synchronization, majority voting and fault detection were presented in details. A hierarchical software architecture was planed during the development of software, consisting of application layer, real-time layer and physical layer. The behavior of the DP-3 dynamic positioning control system was modeled by a Markov model to analyze its reliability. The effects of variation in parameters on the reliability measures were investigated. The time domain dynamic simulation was carried out on a deepwater drilling rig to prove the feasibility of the proposed control architecture.

  5. Dynamic tracking performance of indoor global positioning system: An experimental and theoretical study

    Directory of Open Access Journals (Sweden)

    Gang Zhao

    2015-10-01

    Full Text Available The automation level has been improved rapidly with the introduction of large-scale measurement technologies, such as indoor global positioning system, into the production process among the fields of car, ship, and aerospace due to their excellent measurement characteristics. In fact, the objects are usually in motion during the real measurement process; however, the dynamic measurement characteristics of indoor global positioning system are much limited and still in exploration. In this research, we focused on the dynamic tracking performance of indoor global positioning system and then successfully built a mathematical model based on its measurement principles. We first built single and double station system models with the consideration of measurement objects’ movement. Using MATLAB simulation, we realized the dynamic measurement characteristics of indoor global positioning system. In the real measurement process, the experimental results also support the mathematical model that we built, which proves a great success in dynamic measurement characteristics. We envision that this dynamic tracking performance of indoor global positioning system would shed light on the dynamic measurement of a motion object and therefore make contribution to the automation production.

  6. Dynamics and feedback control of plasma equilibrium position in a tokamak

    International Nuclear Information System (INIS)

    Burenko, O.

    1983-01-01

    A brief history of the beginnings of nuclear fusion research involving toroidal closed-system magnetic plasma containment is presented. A tokamak machine is defined mathematically for the purposes of plasma equilibrium position perturbation analysis. The perturbation equations of a tokamak plasma equilibrium position are developed. Solution of the approximated perturbation equations is carried out. A unique, simple, and useful plasma displacement dynamics transfer function of a tokamak is developed. The dominant time constants of the dynamics transfer function are determined in a symbolic form. This symbolic form of the dynamics transfer function makes it possible to study the stability of a tokamak's plasma equilibrium position. Knowledge of the dynamics transfer function permits systematic syntheses of the required plasma displacement feedback control systems

  7. Adaptive Indoor Positioning Model Based on WLAN-Fingerprinting for Dynamic and Multi-Floor Environments

    Directory of Open Access Journals (Sweden)

    Iyad Husni Alshami

    2017-08-01

    Full Text Available The Global Positioning System demonstrates the significance of Location Based Services but it cannot be used indoors due to the lack of line of sight between satellites and receivers. Indoor Positioning Systems are needed to provide indoor Location Based Services. Wireless LAN fingerprints are one of the best choices for Indoor Positioning Systems because of their low cost, and high accuracy, however they have many drawbacks: creating radio maps is time consuming, the radio maps will become outdated with any environmental change, different mobile devices read the received signal strength (RSS differently, and peoples’ presence in LOS between access points and mobile device affects the RSS. This research proposes a new Adaptive Indoor Positioning System model (called DIPS based on: a dynamic radio map generator, RSS certainty technique and peoples’ presence effect integration for dynamic and multi-floor environments. Dynamic in our context refers to the effects of people and device heterogeneity. DIPS can achieve 98% and 92% positioning accuracy for floor and room positioning, and it achieves 1.2 m for point positioning error. RSS certainty enhanced the positioning accuracy for floor and room for different mobile devices by 11% and 9%. Then by considering the peoples’ presence effect, the error is reduced by 0.2 m. In comparison with other works, DIPS achieves better positioning without extra devices.

  8. Lake topography and wind waves determining seasonal-spatial dynamics of total suspended matter in turbid Lake Taihu, China: assessment using long-term high-resolution MERIS data.

    Science.gov (United States)

    Zhang, Yunlin; Shi, Kun; Liu, Xiaohan; Zhou, Yongqiang; Qin, Boqiang

    2014-01-01

    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 (r(2) = 0.720, pwind speed and TSM concentration (r(2)= 0.685, pwind 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 dynamics were controlled by the lake topography, wind-driven sediment resuspension and SAV distribution.

  9. A review on bridge dynamic displacement monitoring using global positioning system and accelerometer

    Science.gov (United States)

    Yunus, Mohd Zulkifli Mohd; Ibrahim, Nuremira; Ahmad, Fatimah Shafinaz

    2018-02-01

    This paper reviews previous research on bridge dynamic displacement monitoring using Global Positioning System (GPS) and an accelerometer for Structural Health Monitoring (SHM) of bridge. These include the review of the advantages and disadvantages of the measurement as well as the methodology of the measurements used in the recent research study. This review could provide a preliminary decision overview for students or researchers before initiating a research related to the bridge dynamic displacement monitoring.

  10. Position Control of Linear Synchronous Motor Drives with Exploitation of Forced Dynamics Control Principles

    Directory of Open Access Journals (Sweden)

    Jan Vittek

    2004-01-01

    Full Text Available Closed-loop position control of mechanisms directly driven by linear synchronous motors with permanent magnets is presented. The control strategy is based on forced dynamic control, which is a form of feedback linearisation, yielding a non-liner multivariable control law to obtain a prescribed linear speed dynamics together with the vector control condition of mutal orthogonality between the stator current and magnetic flux vectors (assuming perfect estimates of the plant parameters. Outer position control loop is closed via simple feedback with proportional gain. Simulations of the design control sysstem, including the drive with power electronic switching, predict the intended drive performance.

  11. Harsh parenting, child behavior problems, and the dynamic coupling of parents' and children's positive behaviors.

    Science.gov (United States)

    Lunkenheimer, Erika; Ram, Nilam; Skowron, Elizabeth A; Yin, Peifeng

    2017-09-01

    We examined self-reported maternal and paternal harsh parenting (HP) and its effect on the moment-to-moment dynamic coupling of maternal autonomy support and children's positive, autonomous behavior. This positive behavior coupling was measured via hidden Markov models as the likelihood of transitions into specific positive dyadic states in real time. We also examined whether positive behavior coupling, in turn, predicted later HP and child behavior problems. Children (N = 96; age = 3.5 years at Time 1) and mothers completed structured clean-up and puzzle tasks in the laboratory. Mothers' and fathers' HP was associated with children's being less likely to respond positively to maternal autonomy support; mothers' HP was also associated with mothers' being less likely to respond positively to children's autonomous behavior. When mothers responded to children's autonomous behavior with greater autonomy support, children showed fewer externalizing and internalizing problems over time and mothers showed less HP over time. These results were unique to the dynamic coupling of maternal autonomy support and children's autonomous behavior: The overall amount of these positive behaviors did not similarly predict reduced problems. Findings suggest that HP in the family system compromises the coregulation of positive behavior between mother and child and that improving mothers' and children's abilities to respond optimally to one another's autonomy-supportive behaviors may reduce HP and child behavior problems over time. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  12. On the dynamics of traveling phase-oscillators with positive and negative couplings

    International Nuclear Information System (INIS)

    Choi, Jungzae; Choi, Mooyoung; Yoon, Byunggook

    2014-01-01

    We investigate numerically the dynamics of traveling clusters in systems of phase oscillators, some of which possess positive couplings and others negative couplings. The phase distribution, speed of traveling, and average separation between clusters, as well as the order parameters for positive and negative oscillators, are computed as the ratio of the two coupling constants and the fraction of positive oscillators are varied. The dependence of the traveling speed on these parameters is obtained and is observed to fit well with the numerical data of the systems. With the help of this, we describe the conditions for the traveling state to appear in the systems with and without a periodic driving field.

  13. Shallow flows with bottom topography

    NARCIS (Netherlands)

    Heijst, van G.J.F.; Kamp, L.P.J.; Theunissen, R.; Rodi, W.; Uhlmann, M.

    2012-01-01

    This paper discusses laboratory experiments and numerical simulations of dipolar vortex flows in a shallow fluid layer with bottom topography. Two cases are considered: a step topography and a linearly sloping bottom. It is found that viscous effects – i.e., no-slip conditions at the non-horizontal

  14. [Mes differ by positioning: empirical testing of decentralized dynamics of the self].

    Science.gov (United States)

    Mizokami, Shinichi

    2013-10-01

    The present study empirically tested the conceptualization of the decentralized dynamics of the self proposed by Hermans & Kempen (1993), which they developed theoretically and from clinical cases, not from large samples of empirical data. They posited that worldviews and images of the self could vary by positioning even in the same individual, and denied that the ego was an omniscient entity that knew and controlled all aspects of the self (centralized ego). Study 1 tested their conceptualization empirically with 47 university students in an experimental group and 17 as a control group. The results showed that the scores on the Rosenberg's self-esteem scale and images of the Mes in the experimental group significantly varied by positioning, but those in the control group did not. Similar results were found in Study 2 with a sample of 120 university students. These results empirically supported the conceptualization of the decentralized dynamics of the self.

  15. Software development for dynamic position emission tomography: Dynamic image analysis (DIA) tool

    International Nuclear Information System (INIS)

    Pyeon, Do Yeong; Jung, Young Jin; Kim, Jung Su

    2016-01-01

    Positron Emission Tomography(PET) is nuclear medical tests which is a combination of several compounds with a radioactive isotope that can be injected into body to quantitatively measure the metabolic rate (in the body). Especially, Phenomena that increase (sing) glucose metabolism in cancer tissue using the 18F-FDG (Fluorodeoxyglucose) is utilized widely in cancer diagnosis. And then, Numerous studies have been reported that incidence seems high availability even in the modern diagnosis of dementia and Parkinson's (disease) in brain disease. When using a dynamic PET image including the time information in the static information that is provided for the diagnosis many can increase the accuracy of diagnosis. For this reason, clinical researchers getting great attention but, it is the lack of tools to conduct research. And, it interfered complex mathematical algorithm and programming skills for activation of research. In this study, in order to easy to use and enable research dPET, we developed the software based graphic user interface(GUI). In the future, by many clinical researcher using DIA-Tool is expected to be of great help to dPET research

  16. Software development for dynamic position emission tomography: Dynamic image analysis (DIA) tool

    Energy Technology Data Exchange (ETDEWEB)

    Pyeon, Do Yeong; Jung, Young Jin [Dongseo University, Busan (Korea, Republic of); Kim, Jung Su [Dept. of Radilogical Science, Dongnam Health University, Suwon (Korea, Republic of)

    2016-09-15

    Positron Emission Tomography(PET) is nuclear medical tests which is a combination of several compounds with a radioactive isotope that can be injected into body to quantitatively measure the metabolic rate (in the body). Especially, Phenomena that increase (sing) glucose metabolism in cancer tissue using the 18F-FDG (Fluorodeoxyglucose) is utilized widely in cancer diagnosis. And then, Numerous studies have been reported that incidence seems high availability even in the modern diagnosis of dementia and Parkinson's (disease) in brain disease. When using a dynamic PET image including the time information in the static information that is provided for the diagnosis many can increase the accuracy of diagnosis. For this reason, clinical researchers getting great attention but, it is the lack of tools to conduct research. And, it interfered complex mathematical algorithm and programming skills for activation of research. In this study, in order to easy to use and enable research dPET, we developed the software based graphic user interface(GUI). In the future, by many clinical researcher using DIA-Tool is expected to be of great help to dPET research.

  17. Human amygdala response to dynamic facial expressions of positive and negative surprise.

    Science.gov (United States)

    Vrticka, Pascal; Lordier, Lara; Bediou, Benoît; Sander, David

    2014-02-01

    Although brain imaging evidence accumulates to suggest that the amygdala plays a key role in the processing of novel stimuli, only little is known about its role in processing expressed novelty conveyed by surprised faces, and even less about possible interactive encoding of novelty and valence. Those investigations that have already probed human amygdala involvement in the processing of surprised facial expressions either used static pictures displaying negative surprise (as contained in fear) or "neutral" surprise, and manipulated valence by contextually priming or subjectively associating static surprise with either negative or positive information. Therefore, it still remains unresolved how the human amygdala differentially processes dynamic surprised facial expressions displaying either positive or negative surprise. Here, we created new artificial dynamic 3-dimensional facial expressions conveying surprise with an intrinsic positive (wonderment) or negative (fear) connotation, but also intrinsic positive (joy) or negative (anxiety) emotions not containing any surprise, in addition to neutral facial displays either containing ("typical surprise" expression) or not containing ("neutral") surprise. Results showed heightened amygdala activity to faces containing positive (vs. negative) surprise, which may either correspond to a specific wonderment effect as such, or to the computation of a negative expected value prediction error. Findings are discussed in the light of data obtained from a closely matched nonsocial lottery task, which revealed overlapping activity within the left amygdala to unexpected positive outcomes. PsycINFO Database Record (c) 2014 APA, all rights reserved.

  18. Simulation of longitudinal dynamics of long freight trains in positioning operations

    Science.gov (United States)

    Qi, Zhaohui; Huang, Zhihao; Kong, Xianchao

    2012-09-01

    Positioning operations are performed in a railway goods yard, in which the freight train is pulled precisely at a specific point by a positioner. The positioner moves strictly according to the predesigned speed and provides all the traction and braking forces which are highly dependent on the longitudinal dynamic response. In order to improve the efficiency and protect the wagons from damage during positioning operations, the design speed of the positioner has to be optimised based on the simulation of longitudinal train dynamics. However, traditional models of longitudinal train dynamics are not accurate enough in some aspects. In this study, we make some changes in the traditional theory to make it suitable for the study of long freight trains in positioning operations. In the proposed method, instead of the traction force on the train, the motion of the positioner is assumed to be known; more importantly, the traditional draft gear model with nonlinear spring and linear damping is replaced by a more detailed model based on the achievement of contact and impact mechanics; the switching effects of the resistance and the coupler slack are also taken into consideration. Numerical examples that deal with positioning operations on the straight lines, slope lines and curving lines are given.

  19. Metabolic topography of Parkinsonism

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae Seung [Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of)

    2007-04-15

    Parkinson's disease is one of the most frequent neurodegenerative diseases, which mainly affects the elderly. Parkinson's disease is often difficult to differentiate from atypical parkinson disorder such as progressive supranuclear palsy, multiple system atrophy, dementia with Lewy body, and corticobasal ganglionic degeneration, based on the clinical findings because of the similarity of phenotypes and lack of diagnostic markers. The accurate diagnosis of Parkinson's disease and atypical Parkinson disorders is not only important for deciding on treatment regimens and providing prognosis, but also it is critical for studies designed to investigate etiology and pathogenesis of parkinsonism and to develop new therapeutic strategies. Although degeneration of the nigrostriatal dopamine system results in marked loss of striatal dopamine content in most of the diseases causing parkinsonism, pathologic studies revealed different topographies of the neuronal cell loss in Parkinsonism. Since the regional cerebral glucose metabolism is a marker of integrated local synaptic activity and as such is sensitive to both direct neuronal/synaptic damage and secondary functional disruption at synapses distant from the primary site of pathology, and assessment of the regional cerebral glucose metabolism with F-18 FDG PET is useful in the differential diagnosis of parkinsonism and evaluating the pathophysiology of Parkinsonism.

  20. Metabolic topography of Parkinsonism

    International Nuclear Information System (INIS)

    Kim, Jae Seung

    2007-01-01

    Parkinson's disease is one of the most frequent neurodegenerative diseases, which mainly affects the elderly. Parkinson's disease is often difficult to differentiate from atypical parkinson disorder such as progressive supranuclear palsy, multiple system atrophy, dementia with Lewy body, and corticobasal ganglionic degeneration, based on the clinical findings because of the similarity of phenotypes and lack of diagnostic markers. The accurate diagnosis of Parkinson's disease and atypical Parkinson disorders is not only important for deciding on treatment regimens and providing prognosis, but also it is critical for studies designed to investigate etiology and pathogenesis of parkinsonism and to develop new therapeutic strategies. Although degeneration of the nigrostriatal dopamine system results in marked loss of striatal dopamine content in most of the diseases causing parkinsonism, pathologic studies revealed different topographies of the neuronal cell loss in Parkinsonism. Since the regional cerebral glucose metabolism is a marker of integrated local synaptic activity and as such is sensitive to both direct neuronal/synaptic damage and secondary functional disruption at synapses distant from the primary site of pathology, and assessment of the regional cerebral glucose metabolism with F-18 FDG PET is useful in the differential diagnosis of parkinsonism and evaluating the pathophysiology of Parkinsonism

  1. Modulation of dynamic modes by interplay between positive and negative feedback loops in gene regulatory networks

    Science.gov (United States)

    Wang, Liu-Suo; Li, Ning-Xi; Chen, Jing-Jia; Zhang, Xiao-Peng; Liu, Feng; Wang, Wei

    2018-04-01

    A positive and a negative feedback loop can induce bistability and oscillation, respectively, in biological networks. Nevertheless, they are frequently interlinked to perform more elaborate functions in many gene regulatory networks. Coupled positive and negative feedback loops may exhibit either oscillation or bistability depending on the intensity of the stimulus in some particular networks. It is less understood how the transition between the two dynamic modes is modulated by the positive and negative feedback loops. We developed an abstract model of such systems, largely based on the core p53 pathway, to explore the mechanism for the transformation of dynamic behaviors. Our results show that enhancing the positive feedback may promote or suppress oscillations depending on the strength of both feedback loops. We found that the system oscillates with low amplitudes in response to a moderate stimulus and switches to the on state upon a strong stimulus. When the positive feedback is activated much later than the negative one in response to a strong stimulus, the system exhibits long-term oscillations before switching to the on state. We explain this intriguing phenomenon using quasistatic approximation. Moreover, early switching to the on state may occur when the system starts from a steady state in the absence of stimuli. The interplay between the positive and negative feedback plays a key role in the transitions between oscillation and bistability. Of note, our conclusions should be applicable only to some specific gene regulatory networks, especially the p53 network, in which both oscillation and bistability exist in response to a certain type of stimulus. Our work also underscores the significance of transient dynamics in determining cellular outcome.

  2. Satellite remote sensing of landscape freeze/thaw state dynamics for complex Topography and Fire Disturbance Areas Using multi-sensor radar and SRTM digital elevation models

    Science.gov (United States)

    Podest, Erika; McDonald, Kyle; Kimball, John; Randerson, James

    2003-01-01

    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 dynamics 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.

  3. Design and experiments with scale model of a ship with dynamic positioning system

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Carlos Eduardo S.; Morishita, Helio M.; Moratelli Junior, Lazaro; Lago, Glenan A.; Tannuri, Eduardo A. [Universidade de Sao Paulo (USP), SP (Brazil)

    2008-07-01

    Dynamic Positioning Systems (DPS) are used to keep a floating vessel on a specific position or follow pre-defined path through the action of controlled propellers. This paper describes a facility used to experimentally analyze DPS and to validate a numerical simulator. It is composed by a scale model of a DP tanker with 3 thrusters, a measurement system based on computational vision and a control software with the same DP algorithms used in industrial systems. Simple wind and current generators were also implemented. This work shows preliminary results of experiments, which has been useful to calibrate the simulator and to validate the mathematical model. (author)

  4. Aging and emotional expressions: is there a positivity bias during dynamic emotion recognition?

    Directory of Open Access Journals (Sweden)

    Alberto eDi Domenico

    2015-08-01

    Full Text Available In this study, we investigated whether age-related differences in emotion regulation priorities influence online dynamic emotional facial discrimination. A group of 40 younger and a group of 40 older adults were invited to recognize a positive or negative expression as soon as the expression slowly emerged and subsequently rate it in terms of intensity. Our findings show that older adults recognized happy expressions faster than angry ones, while the direction of emotional expression does not seem to affect younger adults’ performance. Furthermore, older adults rated both negative and positive emotional faces as more intense compared to younger controls. This study detects age-related differences with a dynamic online paradigm and suggests that different regulation strategies may shape emotional face recognition.

  5. Spectral analysis of the gravity and topography of Mars

    Science.gov (United States)

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

    1993-01-01

    New spherical harmonic models of the gravity and topography of Mars place important constraints on the structure and dynamics of the interior. The gravity and topography models are significantly phase coherent for harmonic degrees n less than 30 (wavelengths greater than 700 km). Loss of coherence below that wavelength is presumably due to inadequacies of the models, rather than a change in behavior of the planet. The gravity/topography 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 dynamic 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 topography model was derived by harmonic analysis of the USGS digital elevation model of Mars. Before comparing gravity and topography 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 topography, 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.

  6. Aging and emotional expressions: is there a positivity bias during dynamic emotion recognition?

    OpenAIRE

    Di Domenico, Alberto; Palumbo, Rocco; Mammarella, Nicola; Fairfield, Beth

    2015-01-01

    In this study, we investigated whether age-related differences in emotion regulation priorities influence online dynamic emotional facial discrimination. A group of 40 younger and a group of 40 older adults were invited to recognize a positive or negative expression as soon as the expression slowly emerged and subsequently rate it in terms of intensity. Our findings show that older adults recognized happy expressions faster than angry ones, while the direction of emotional expression does not...

  7. A High Dynamic-Range Beam Position Measurement System for ELSA-2

    CERN Document Server

    Balleyguier, P; Guimbal, P; Borrion, H

    2003-01-01

    New beamlines are presently under construction for ELSA, a 20 MeV electron linac located at Bruyères-le-Châtel. These lines need a beam position measurement system filling the following requirements: small footprint, wide dynamic range, single-bunch/multi-bunch capability, simple design. We designed a compact 4-stripline sensor and an electronic treatment chain based on logarithmic amplifiers. This paper presents the design, cold and hot test results.

  8. Positive Analysis of Invasive Species Control as a Dynamic Spatial Process

    OpenAIRE

    Buyuktahtakin, Esra; Feng, Zhuo; Olsson, Aaryn; Frisvold, George B.; Szidarovszky, Ferenc

    2010-01-01

    This paper models control of invasive buffelgrass (Pennisetum ciliare), a fire-prone African bunchgrass spreading rapidly across the southern Arizona desert as a spatial dynamic process. Buffelgrass spreads over a gridded landscape. Weed carrying capacity, treatment costs, and damages vary over grid cells. Damage from buffelgrass depends on its spatial distribution in relation to valued resources. We conduct positive analysis of recommended heuristic strategies for buffelgrass control, evalua...

  9. Open-loop position tracking control of a piezoceramic flexible beam using a dynamic hysteresis compensator

    International Nuclear Information System (INIS)

    Nguyen, Phuong-Bac; Choi, Seung-Bok

    2010-01-01

    This paper proposes a novel hysteresis compensator to enhance control accuracy in open-loop position tracking control of a piezoceramic flexible beam. The proposed hysteresis compensator consists of two components: a rate-independent hysteresis compensator and a nonlinear filter. The compensator is formulated based on the inverse Preisach model, while the weight coefficients of the filter are identified adaptively using a recursive least square (RLS) algorithm. In this work, two dynamic hysteresis compensators (or rate-independent hysteresis compensators) are developed by adopting two different nonlinear filters: Volterra and bilinear filters. In order to demonstrate the improved control accuracy of the proposed dynamic compensators, a flexible beam associated with the piezoceramic actuator is modeled using the finite element method (FEM) and Euler–Bernoulli beam theory. The beam model is then integrated with the proposed hysteresis model to achieve accurate position tracking control at the tip of the beam. An experimental investigation on the tip position tracking control is undertaken by realizing three different hysteresis compensators: a rate-independent hysteresis compensator, a rate-dependent hysteresis compensator with a Volterra nonlinear filter and a rate-independent hysteresis compensator with a bilinear nonlinear filter. It is shown that the proposed dynamic hysteresis compensators can provide much better tracking control accuracy than conventional rate-independent hysteresis compensators

  10. Coarsely resolved topography along protein folding pathways

    Science.gov (United States)

    Fernández, Ariel; Kostov, Konstantin S.; Berry, R. Stephen

    2000-03-01

    The kinetic data from the coarse representation of polypeptide torsional dynamics described in the preceding paper [Fernandez and Berry, J. Chem. Phys. 112, 5212 (2000), preceding paper] is inverted by using detailed balance to obtain a topographic description of the potential-energy surface (PES) along the dominant folding pathway of the bovine pancreatic trypsin inhibitor (BPTI). The topography is represented as a sequence of minima and effective saddle points. The dominant folding pathway displays an overall monotonic decrease in energy with a large number of staircaselike steps, a clear signature of a good structure-seeker. The diversity and availability of alternative folding pathways is analyzed in terms of the Shannon entropy σ(t) associated with the time-dependent probability distribution over the kinetic ensemble of contact patterns. Several stages in the folding process are evident. Initially misfolded states form and dismantle revealing no definite pattern in the topography and exhibiting high Shannon entropy. Passage down a sequence of staircase steps then leads to the formation of a nativelike intermediate, for which σ(t) is much lower and fairly constant. Finally, the structure of the intermediate is refined to produce the native state of BPTI. We also examine how different levels of tolerance to mismatches of side chain contacts influence the folding kinetics, the topography of the dominant folding pathway, and the Shannon entropy. This analysis yields upper and lower bounds of the frustration tolerance required for the expeditious and robust folding of BPTI.

  11. Dynamics of gene expression with positive feedback to histone modifications at bivalent domains

    Science.gov (United States)

    Huang, Rongsheng; Lei, Jinzhi

    2018-03-01

    Experiments have shown that in embryonic stem cells, the promoters of many lineage-control genes contain “bivalent domains”, within which the nucleosomes possess both active (H3K4me3) and repressive (H3K27me3) marks. Such bivalent modifications play important roles in maintaining pluripotency in embryonic stem cells. Here, to investigate gene expression dynamics when there are regulations in bivalent histone modifications and random partition in cell divisions, we study how positive feedback to histone methylation/demethylation controls the transition dynamics of the histone modification patterns along with cell cycles. We constructed a computational model that includes dynamics of histone marks, three-stage chromatin state transitions, transcription and translation, feedbacks from protein product to enzymes to regulate the addition and removal of histone marks, and the inheritance of nucleosome state between cell cycles. The model reveals how dynamics of both nucleosome state transition and gene expression are dependent on the enzyme activities and feedback regulations. Results show that the combination of stochastic histone modification at each cell division and the deterministic feedback regulation work together to adjust the dynamics of chromatin state transition in stem cell regenerations.

  12. Position-Dependent Dynamics Explain Pore-Averaged Diffusion in Strongly Attractive Adsorptive Systems.

    Science.gov (United States)

    Krekelberg, William P; Siderius, Daniel W; Shen, Vincent K; Truskett, Thomas M; Errington, Jeffrey R

    2017-12-12

    Using molecular simulations, we investigate the relationship between the pore-averaged and position-dependent self-diffusivity of a fluid adsorbed in a strongly attractive pore as a function of loading. Previous work (Krekelberg, W. P.; Siderius, D. W.; Shen, V. K.; Truskett, T. M.; Errington, J. R. Connection between thermodynamics and dynamics of simple fluids in highly attractive pores. Langmuir 2013, 29, 14527-14535, doi: 10.1021/la4037327) established that pore-averaged self-diffusivity in the multilayer adsorption regime, where the fluid exhibits a dense film at the pore surface and a lower density interior pore region, is nearly constant as a function of loading. Here we show that this puzzling behavior can be understood in terms of how loading affects the fraction of particles that reside in the film and interior pore regions as well as their distinct dynamics. Specifically, the insensitivity of pore-averaged diffusivity to loading arises from the approximate cancellation of two factors: an increase in the fraction of particles in the higher diffusivity interior pore region with loading and a corresponding decrease in the particle diffusivity in that region. We also find that the position-dependent self-diffusivities scale with the position-dependent density. We present a model for predicting the pore-average self-diffusivity based on the position-dependent self-diffusivity, which captures the unusual characteristics of pore-averaged self-diffusivity in strongly attractive pores over several orders of magnitude.

  13. Linguistic positivity in historical texts reflects dynamic environmental and psychological factors.

    Science.gov (United States)

    Iliev, Rumen; Hoover, Joe; Dehghani, Morteza; Axelrod, Robert

    2016-12-06

    People use more positive words than negative words. Referred to as "linguistic positivity bias" (LPB), this effect has been found across cultures and languages, prompting the conclusion that it is a panhuman tendency. However, although multiple competing explanations of LPB have been proposed, there is still no consensus on what mechanism(s) generate LPB or even on whether it is driven primarily by universal cognitive features or by environmental factors. In this work we propose that LPB has remained unresolved because previous research has neglected an essential dimension of language: time. In four studies conducted with two independent, time-stamped text corpora (Google books Ngrams and the New York Times), we found that LPB in American English has decreased during the last two centuries. We also observed dynamic fluctuations in LPB that were predicted by changes in objective environment, i.e., war and economic hardships, and by changes in national subjective happiness. In addition to providing evidence that LPB is a dynamic phenomenon, these results suggest that cognitive mechanisms alone cannot account for the observed dynamic fluctuations in LPB. At the least, LPB likely arises from multiple interacting mechanisms involving subjective, objective, and societal factors. In addition to having theoretical significance, our results demonstrate the value of newly available data sources in addressing long-standing scientific questions.

  14. Portraying Temporal Dynamics of Urban Spatial Divisions with Mobile Phone Positioning Data: A Complex Network Approach

    Directory of Open Access Journals (Sweden)

    Meng Zhou

    2016-12-01

    Full Text Available Spatial structure is a fundamental characteristic of cities that influences the urban functioning to a large extent. While administrative partitioning is generally done in the form of static spatial division, understanding a more temporally dynamic structure of the urban space would benefit urban planning and management immensely. This study makes use of a large-scale mobile phone positioning dataset to characterize the diurnal dynamics of the interaction-based urban spatial structure. To extract the temporally vibrant structure, spatial interaction networks at different times are constructed based on the movement connections of individuals between geographical units. Complex network community detection technique is applied to identify the spatial divisions as well as to quantify their temporal dynamics. Empirical analysis is conducted using data containing all user positions on a typical weekday in Shenzhen, China. Results are compared with official zoning and planned structure and indicate a certain degree of expansion in urban central areas and fragmentation in industrial suburban areas. A high level of variability in spatial divisions at different times of day is detected with some distinct temporal features. Peak and pre-/post-peak hours witness the most prominent fluctuation in spatial division indicating significant change in the characteristics of movements and activities during these periods of time. Findings of this study demonstrate great potential of large-scale mobility data in supporting intelligent spatial decision making and providing valuable knowledge to the urban planning sectors.

  15. Airborne laser altimeter measurements of landscape topography

    International Nuclear Information System (INIS)

    Ritchie, J.C.

    1995-01-01

    Measurements of topography can provide a wealth of information on landscape properties for managing hydrologic and geologic systems and conserving natural and agricultural resources. This article discusses the application of an airborne laser altimeter to measure topography and other landscape surface properties. The airborne laser altimeter makes 4000 measurements per second with a vertical recording resolution of 5 cm. Data are collected digitally with a personal computer. A video camera, borehole sighted with the laser, records an image for locating flight lines. GPS data are used to locate flight line positions on the landscape. Laser data were used to measure vegetation canopy topography, height, cover, and distribution and to measure microtopography of the land surface and gullies with depths of 15–20 cm. Macrotopography of landscape profiles for segments up to 4 km were in agreement with available topographic maps but provided more detail. Larger gullies with and without vegetation, and stream channel cross sections and their associated floodplains have also been measured and reported in other publications. Landscape segments for any length could be measured for either micro- or macrotopography. Airborne laser altimeter measurements of landscape profiles can provide detailed information on landscape properties or specific needs that will allow better decisions on the design and location of structures (i.e., roads, pipe, and power lines) and for improving the management and conservation of natural and agricultural landscapes. (author)

  16. Position-Invariant Robust Features for Long-Term Recognition of Dynamic Outdoor Scenes

    Science.gov (United States)

    Kawewong, Aram; Tangruamsub, Sirinart; Hasegawa, Osamu

    A novel Position-Invariant Robust Feature, designated as PIRF, is presented to address the problem of highly dynamic scene recognition. The PIRF is obtained by identifying existing local features (i.e. SIFT) that have a wide baseline visibility within a place (one place contains more than one sequential images). These wide-baseline visible features are then represented as a single PIRF, which is computed as an average of all descriptors associated with the PIRF. Particularly, PIRFs are robust against highly dynamical changes in scene: a single PIRF can be matched correctly against many features from many dynamical images. This paper also describes an approach to using these features for scene recognition. Recognition proceeds by matching an individual PIRF to a set of features from test images, with subsequent majority voting to identify a place with the highest matched PIRF. The PIRF system is trained and tested on 2000+ outdoor omnidirectional images and on COLD datasets. Despite its simplicity, PIRF offers a markedly better rate of recognition for dynamic outdoor scenes (ca. 90%) than the use of other features. Additionally, a robot navigation system based on PIRF (PIRF-Nav) can outperform other incremental topological mapping methods in terms of time (70% less) and memory. The number of PIRFs can be reduced further to reduce the time while retaining high accuracy, which makes it suitable for long-term recognition and localization.

  17. ATM Coastal Topography-Mississippi, 2001

    Science.gov (United States)

    Nayegandhi, Amar; Yates, Xan; Brock, John C.; Sallenger, A.H.; Klipp, Emily S.; Wright, C. Wayne

    2009-01-01

    These remotely sensed, geographically referenced elevation measurements of lidar-derived first-surface (FS) topography 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 topography 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 topography 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

  18. ATM Coastal Topography-Alabama 2001

    Science.gov (United States)

    Nayegandhi, Amar; Yates, Xan; Brock, John C.; Sallenger, A.H.; Bonisteel, Jamie M.; Klipp, Emily S.; Wright, C. Wayne

    2009-01-01

    These remotely sensed, geographically referenced elevation measurements of Lidar-derived first surface (FS) topography 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 topography 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 topography 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

  19. The Holy See on sexual and reproductive health rights: conservative in position, dynamic in response.

    Science.gov (United States)

    Coates, Amy L; Hill, Peter S; Rushton, Simon; Balen, Julie

    2014-11-01

    The Holy See has engaged extensively in United Nations negotiations on issues concerning sexual and reproductive health rights as they have emerged and evolved in a dynamic global agenda over the past two decades. A meta-narrative review of the mission's official statements was conducted to examine the positions, discourses and tensions across the broad range of agendas. The Holy See represents a fundamentally conservative and stable position on a range of sexual and reproductive health rights concerns. However, the mission has been dynamic in the ways in which it has forwarded its arguments, increasingly relying upon secularised technical claims and empirical evidence; strategically interpreting human rights norms in ways consistent with its own position; and framing sexuality and reproduction in the context of "the family". Seen in the broader context of a "religious resurgence" in international relations, and in light of the fact that the Holy See has frequently sought to form alliances with conservative State and non-State actors, these findings make an important contribution to understanding the slow progress as well as the potential obstacles that lie ahead in the battle to realise sexual and reproductive health rights in a changing global political environment. Copyright © 2014 Reproductive Health Matters. Published by Elsevier Ltd. All rights reserved.

  20. Dynamic Positioning Capability Analysis for Marine Vessels Based on A DPCap Polar Plot Program

    Science.gov (United States)

    Wang, Lei; Yang, Jian-min; Xu, Sheng-wen

    2018-03-01

    Dynamic positioning capability (DPCap) analysis is essential in the selection of thrusters, in their configuration, and during preliminary investigation of the positioning ability of a newly designed vessel dynamic positioning system. DPCap analysis can help determine the maximum environmental forces, in which the DP system can counteract in given headings. The accuracy of the DPCap analysis is determined by the precise estimation of the environmental forces as well as the effectiveness of the thrust allocation logic. This paper is dedicated to developing an effective and efficient software program for the DPCap analysis for marine vessels. Estimation of the environmental forces can be obtained by model tests, hydrodynamic computation and empirical formulas. A quadratic programming method is adopted to allocate the total thrust on every thruster of the vessel. A detailed description of the thrust allocation logic of the software program is given. The effectiveness of the new program DPCap Polar Plot (DPCPP) was validated by a DPCap analysis for a supply vessel. The present study indicates that the developed program can be used in the DPCap analysis for marine vessels. Moreover, DPCap analysis considering the thruster failure mode might give guidance to the designers of vessels whose thrusters need to be safer.

  1. Dynamics of Brokerage Positions in Clusters: Evidence from the Spanish Foodstuffs Industry

    Directory of Open Access Journals (Sweden)

    José Antonio Belso-Martínez

    2017-02-01

    Full Text Available Shifting away from traditional approaches orientated towards the analysis of the benefits associated with brokerage, this paper provides valuable insights into the dynamics of this network position and the opportunities to innovate that it provides. Using fine grain micro data collected in a foodstuff Spanish cluster, the evolution of different brokerage profiles is analyzed in depth. It was particularly evident how firm-level characteristics (status, former mediating experience and external openness and their interactions may generate changes in the different brokerage roles over a period of time. The findings of this work partially validate expectations based on the network dynamics approaches. Status and previous mediating experience facilitate the creation of partnerships, fostering brokerage. Conversely, interaction effects demote brokerage activity at the intra-cluster level, suggesting the selective nature of brokers’ relational behavior.

  2. The application of confocal technology based on polycapillary X-ray optics in surface topography

    International Nuclear Information System (INIS)

    Zhao, Guangcui; Sun, Tianxi; Liu, Zhiguo; Yuan, Hao; Li, Yude; Liu, Hehe; Zhao, Weigang; Zhang, Ruixia; Min, Qin; Peng, Song

    2013-01-01

    A confocal micro-X-ray fluorescence (MXRF) technology based on polycapillary X-ray optics was proposed for determining surface topography. This confocal topography method involves elemental sensitivity and can be used to classify the objects according to their elemental composition while obtaining their surface topography. To improve the spatial resolution of this confocal topography technology, the center of the confocal micro-volume was overlapped with the output focal spot of the polycapillary X-ray, focusing the lens in the excitation channel. The input focal spot of the X-ray lens parallel to the detection channel was used to determine the surface position of the sample. The corresponding surface adaptive algorithm was designed to obtain the surface topography. The surface topography of a ceramic chip was obtained. This confocal MXRF surface topography method could find application in the materials sciences

  3. Dynamic Infrared Thermography Study of Blood Flow Relative to Lower Limp Position

    Science.gov (United States)

    Stathopoulos, I.; Skouroliakou, K.; Michail, C.; Valais, I.

    2015-09-01

    Thermography is an established method for studying skin temperature distribution. Temperature distribution on body surface is influenced by a variety of physiological mechanisms and has been proven a reliable indicator of various physiological disorders. Blood flow is an important factor that influences body heat diffusion and skin temperature. In an attempt to validate and further elucidate thermal models characterizing the human skin, dynamic thermography of the lower limp in horizontal and vertical position was performed, using a FLIR T460 thermographic camera. Temporal variation of temperature was recorded on five distinct points of the limp. Specific points were initially cooled by the means of an ice cube and measurements of the skin temperature were obtained every 30 seconds as the skin temperature was locally reduced and afterwards restored at its initial value. The return to thermal balance followed roughly the same pattern for all points of measurement, although the heating rate was faster when the foot was in horizontal position. Thermal balance was achieved faster at the spots that were positioned on a vein passage. Our results confirm the influence of blood flow on the thermal regulation of the skin. Spots located over veins exhibit different thermal behaviour due to thermal convection through blood flow. Changing the position of the foot from vertical to horizontal, effectively affects blood perfusion as in the vertical position blood circulation is opposed by gravity.

  4. Asymmetric three-dimensional topography over mantle plumes.

    Science.gov (United States)

    Burov, Evgueni; Gerya, Taras

    2014-09-04

    The role of mantle-lithosphere interactions in shaping surface topography has long been debated. In general, it is supposed that mantle plumes and vertical mantle flows result in axisymmetric, long-wavelength topography, which strongly differs from the generally asymmetric short-wavelength topography created by intraplate tectonic forces. However, identification of mantle-induced topography 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' topography (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 topography 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 topography 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 dynamic topography, mantle-lithosphere interactions, and continental break-up processes above mantle plumes.

  5. Quantitative Assessment of the Effects of Orientational and Positional Disorder on Glassy Dynamics

    International Nuclear Information System (INIS)

    Ramos, M.; Vieira, S.; Bermejo, F.; Dawidowski, J.; Fischer, H.; Schober, H.; Gonzalez, M.; Loong, C.; Price, D.

    1997-01-01

    The microscopic dynamics of several phases of solid ethanol are studied under the same thermodynamic conditions by inelastic neutron scattering. It is found that the vibrational density of states of the orientational glass phase, where the molecules are arranged on an ordered lattice but with disordered orientations, is very similar to that of the structural glass phase, where the molecules are disordered both in position and orientation. Low-temperature specific heat measurements on the same phases strongly support the neutron measurements. We therefore find that positional disorder, even in a stoichiometrically homogeneous system such as ethanol, is not essential for the manifestation of glasslike behavior to an extent comparable with that exhibited by the structural glass. copyright 1996 The American Physical Society

  6. Soft tissue deformation for surgical simulation: a position-based dynamics approach.

    Science.gov (United States)

    Camara, Mafalda; Mayer, Erik; Darzi, Ara; Pratt, Philip

    2016-06-01

    To assist the rehearsal and planning of robot-assisted partial nephrectomy, a real-time simulation platform is presented that allows surgeons to visualise and interact with rapidly constructed patient-specific biomechanical models of the anatomical regions of interest. Coupled to a framework for volumetric deformation, the platform furthermore simulates intracorporeal 2D ultrasound image acquisition, using preoperative imaging as the data source. This not only facilitates the planning of optimal transducer trajectories and viewpoints, but can also act as a validation context for manually operated freehand 3D acquisitions and reconstructions. The simulation platform was implemented within the GPU-accelerated NVIDIA FleX position-based dynamics framework. In order to validate the model and determine material properties and other simulation parameter values, a porcine kidney with embedded fiducial beads was CT-scanned and segmented. Acquisitions for the rest position and three different levels of probe-induced deformation were collected. Optimal values of the cluster stiffness coefficients were determined for a range of different particle radii, where the objective function comprised the mean distance error between real and simulated fiducial positions over the sequence of deformations. The mean fiducial error at each deformation stage was found to be compatible with the level of ultrasound probe calibration error typically observed in clinical practice. Furthermore, the simulation exhibited unconditional stability on account of its use of clustered shape-matching constraints. A novel position-based dynamics implementation of soft tissue deformation has been shown to facilitate several desirable simulation characteristics: real-time performance, unconditional stability, rapid model construction enabling patient-specific behaviour and accuracy with respect to reference CT images.

  7. Positive Selection or Free to Vary? Assessing the Functional Significance of Sequence Change Using Molecular Dynamics.

    Directory of Open Access Journals (Sweden)

    Jane R Allison

    Full Text Available Evolutionary arms races between pathogens and their hosts may be manifested as selection for rapid evolutionary change of key genes, and are sometimes detectable through sequence-level analyses. In the case of protein-coding genes, such analyses frequently predict that specific codons are under positive selection. However, detecting positive selection can be non-trivial, and false positive predictions are a common concern in such analyses. It is therefore helpful to place such predictions within a structural and functional context. Here, we focus on the p19 protein from tombusviruses. P19 is a homodimer that sequesters siRNAs, thereby preventing the host RNAi machinery from shutting down viral infection. Sequence analysis of the p19 gene is complicated by the fact that it is constrained at the sequence level by overprinting of a viral movement protein gene. Using homology modeling, in silico mutation and molecular dynamics simulations, we assess how non-synonymous changes to two residues involved in forming the dimer interface-one invariant, and one predicted to be under positive selection-impact molecular function. Interestingly, we find that both observed variation and potential variation (where a non-synonymous change to p19 would be synonymous for the overprinted movement protein does not significantly impact protein structure or RNA binding. Consequently, while several methods identify residues at the dimer interface as being under positive selection, MD results suggest they are functionally indistinguishable from a site that is free to vary. Our analyses serve as a caveat to using sequence-level analyses in isolation to detect and assess positive selection, and emphasize the importance of also accounting for how non-synonymous changes impact structure and function.

  8. Locally optimal control under unknown dynamics with learnt cost function: application to industrial robot positioning

    Science.gov (United States)

    Guérin, Joris; Gibaru, Olivier; Thiery, Stéphane; Nyiri, Eric

    2017-01-01

    Recent methods of Reinforcement Learning have enabled to solve difficult, high dimensional, robotic tasks under unknown dynamics using iterative Linear Quadratic Gaussian control theory. These algorithms are based on building a local time-varying linear model of the dynamics from data gathered through interaction with the environment. In such tasks, the cost function is often expressed directly in terms of the state and control variables so that it can be locally quadratized to run the algorithm. If the cost is expressed in terms of other variables, a model is required to compute the cost function from the variables manipulated. We propose a method to learn the cost function directly from the data, in the same way as for the dynamics. This way, the cost function can be defined in terms of any measurable quantity and thus can be chosen more appropriately for the task to be carried out. With our method, any sensor information can be used to design the cost function. We demonstrate the efficiency of this method through simulating, with the V-REP software, the learning of a Cartesian positioning task on several industrial robots with different characteristics. The robots are controlled in joint space and no model is provided a priori. Our results are compared with another model free technique, consisting in writing the cost function as a state variable.

  9. Dynamic Positioning System (DPS) Risk Analysis Using Probabilistic Risk Assessment (PRA)

    Science.gov (United States)

    Thigpen, Eric B.; Boyer, Roger L.; Stewart, Michael A.; Fougere, Pete

    2017-01-01

    The National Aeronautics and Space Administration (NASA) Safety & Mission Assurance (S&MA) directorate at the Johnson Space Center (JSC) has applied its knowledge and experience with Probabilistic Risk Assessment (PRA) to projects in industries ranging from spacecraft to nuclear power plants. PRA is a comprehensive and structured process for analyzing risk in complex engineered systems and/or processes. The PRA process enables the user to identify potential risk contributors such as, hardware and software failure, human error, and external events. Recent developments in the oil and gas industry have presented opportunities for NASA to lend their PRA expertise to both ongoing and developmental projects within the industry. This paper provides an overview of the PRA process and demonstrates how this process was applied in estimating the probability that a Mobile Offshore Drilling Unit (MODU) operating in the Gulf of Mexico and equipped with a generically configured Dynamic Positioning System (DPS) loses location and needs to initiate an emergency disconnect. The PRA described in this paper is intended to be generic such that the vessel meets the general requirements of an International Maritime Organization (IMO) Maritime Safety Committee (MSC)/Circ. 645 Class 3 dynamically positioned vessel. The results of this analysis are not intended to be applied to any specific drilling vessel, although provisions were made to allow the analysis to be configured to a specific vessel if required.

  10. Optimal Control Method of Robot End Position and Orientation Based on Dynamic Tracking Measurement

    Science.gov (United States)

    Liu, Dalong; Xu, Lijuan

    2018-01-01

    In order to improve the accuracy of robot pose positioning and control, this paper proposed a dynamic tracking measurement robot pose optimization control method based on the actual measurement of D-H parameters of the robot, the parameters is taken with feedback compensation of the robot, according to the geometrical parameters obtained by robot pose tracking measurement, improved multi sensor information fusion the extended Kalan filter method, with continuous self-optimal regression, using the geometric relationship between joint axes for kinematic parameters in the model, link model parameters obtained can timely feedback to the robot, the implementation of parameter correction and compensation, finally we can get the optimal attitude angle, realize the robot pose optimization control experiments were performed. 6R dynamic tracking control of robot joint robot with independent research and development is taken as experimental subject, the simulation results show that the control method improves robot positioning accuracy, and it has the advantages of versatility, simplicity, ease of operation and so on.

  11. Optimization of detectors positioning with respect to flying dynamics for future formation flight missions

    Science.gov (United States)

    Civitani, Marta; Djalal, Sophie; Chipaux, Remi

    2009-08-01

    In a X-ray telescope in formation flight configuration, the optics and the focal-plane detectors reside in two different spacecraft. The dynamics of the detector spacecraft (DSC) with respect to the mirror spacecraft (MSC, carrying the mirrors of the telescope) changes continuously the arrival positions of the photons on the detectors. In this paper we analyze this issue for the case of the SIMBOL-X hard X-ray mission, extensively studied by CNES and ASI until 2009 spring. Due to the existing gaps between pixels and between detector modules, the dynamics of the system may produce a relevant photometric effect. The aim of this work is to present the optimization study of the control-law algorithm with respect to the detector's geometry. As the photometric effect may vary depending upon position of the source image on the detector, the analysis-carried out using the simuLOS (INAF, CNES, CEA) simulation tool-is extended over the entire SIMBOL-X field of view.

  12. Dynamic Characteristics of Positive Pulsed Dielectric Barrier Discharge for Ozone Generation in Air

    International Nuclear Information System (INIS)

    Wei Linsheng; Peng Bangfa; Li Ming; Zhang Yafang; Hu Zhaoji

    2016-01-01

    A comprehensive dynamic model consisting of 66 reactions and 24 species is developed to investigate the dynamic characteristics of ozone generation by positive pulsed dielectric barrier discharge (DBD) using parallel-plate reactor in air. The electron energy conservation equation is coupled to the electron continuity equation, the heavy species continuity equation, and Poisson's equation for a better description. The reliability of the model is experimentally confirmed. The model can be used to predict the temporal and spatial evolution of species, as well as streamer propagation. The simulation results show that electron density increases nearly exponentially in the direction to the anode at the electron avalanche. Streamer propagation velocity is about 5.26 × 10 4 m/s from anode to cathode in the simulated condition. The primary positive ion, negative ion, and excited species are O 2 + , O 3 − and O 2 ( 1 Δg) in pulsed DBD in air, respectively. N 2 O has the largest density among nitrogen oxides. e and N 2 + densities in the streamer head increase gradually to maximum values with the development of the streamer. Meanwhile, the O 2 + , O, O 3 , N 2 (A 3 Σ) and N 2 O densities reach maximum values in the vicinity of the anode. (paper)

  13. Effect of dynamic temperature stimulus to plantar surface of the foot in the standing position

    Directory of Open Access Journals (Sweden)

    Ryo Watanabe

    2016-11-01

    Full Text Available We have previously found that a vertical force or tactile sensation occurs when the temperature of a participant's skin changes rapidly. In this illusion, upward motion, pressure or force sensation is elicited when stimulus temperature rises rapidly, whereas in the opposite case, downward motion or pulling sensation is elicited. In this paper, we applied this phenomenon to the sole (plantar surface of the foot to present the sensation of ground slope. To investigate this, we conducted an experiment that measured the correlation between stimulation temperature and front-back direction position of the center of gravity (COG. Participants stood on a thermal stimulator on Nintendo Wii Balance Board (WBB and they remained standing during 30 s dynamic temperature stimulus. In result of analysis, it was suggested that dynamic thermal change in sole might influence standing position and the effect pattern was anomalous in case of the participants who reported a swaying sensation without a haptic sensation. This behavior might be applied to the diagnosis of the presence of thermoesthesia of the patients who might have disease with absence of thermoesthesia.

  14. Dynamic performance of the beam position monitor support at the SSRF.

    Science.gov (United States)

    Wang, Xiao; Cao, Yun; Du, Hanwen; Yin, Lixin

    2009-01-01

    Electron beam stability is very important for third-generation light sources, especially for the Shanghai Synchrotron Radiation Facility whose ground vibrations are much larger than those for other light sources. Beam position monitors (BPMs), used to monitor the position of the electron beam, require a greater stability than other mechanical structures. This paper concentrates on an investigation of the dynamic performance of the BPM support prototype. Modal and response analyses have been carried out by finite-element (FE) calculations and vibration measurements. Inconsistent results between calculation and measurement have motivated a change in the soft connections between the support and the ground from a ground bolt in the initial design to full grout. As a result the mechanical stability of the BPM support is greatly improved, showing an increase in the first eigenfrequency from 20.2 Hz to 50.2 Hz and a decrease in the ratio of the root-mean-square displacement (4-50 Hz) between the ground and the top of the support from 4.36 to 1.23 in the lateral direction. An example is given to show how FE analysis can guide the mechanical design and dynamic measurements (i.e. it is not just used as a verification method). Similar ideas can be applied to improve the stability of other mechanical structures.

  15. Ocean and laboratory observations on waves over topography

    NARCIS (Netherlands)

    Lam, F.P. A.

    2007-01-01

    This thesis addresses the observation, analysis and dynamics of waves as being trapped, generated and focused by sloping topography. ---Shelf waves with diurnal tidal frequency off Greenland--- Tidal analysis has been carried out on current measurements at a “cross-shelf” transect off Greenland at

  16. Dynamic positional fate map of the primary heart-forming region.

    Science.gov (United States)

    Cui, Cheng; Cheuvront, Tracey J; Lansford, Rusty D; Moreno-Rodriguez, Ricardo A; Schultheiss, Thomas M; Rongish, Brenda J

    2009-08-15

    Here we show the temporal-spatial orchestration of early heart morphogenesis at cellular level resolution, in vivo, and reconcile conflicting positional fate mapping data regarding the primary heart-forming field(s). We determined the positional fates of precardiac cells using a precision electroporation approach in combination with wide-field time-lapse microscopy in the quail embryo, a warm-blooded vertebrate (HH Stages 4 through 10). Contrary to previous studies, the results demonstrate the existence of a "continuous" circle-shaped heart field that spans the midline, appearing at HH Stage 4, which then expands to form a wide arc of progenitors at HH Stages 5-7. Our time-resolved image data show that a subset of these cardiac progenitor cells do not overlap with the expression of common cardiogenic factors, Nkx-2.5 and Bmp-2, until HH Stage 10, when a tubular heart has formed, calling into question when cardiac fate is specified and by which key factors. Sub-groups and anatomical bands (cohorts) of heart precursor cells dramatically change their relative positions in a process largely driven by endodermal folding and other large-scale tissue deformations. Thus, our novel dynamic positional fate maps resolve the origin of cardiac progenitor cells in amniotes. The data also establish the concept that tissue motion contributes significantly to cellular position fate - i.e., much of the cellular displacement that occurs during assembly of a midline heart tube (HH Stage 9) is NOT due to "migration" (autonomous motility), a commonly held belief. Computational analysis of our time-resolved data lays the foundation for more precise analyses of how cardiac gene regulatory networks correlate with early heart tissue morphogenesis in birds and mammals.

  17. Magnetosphere and ionosphere response to a positive-negative pulse pair of solar wind dynamic pressure

    Science.gov (United States)

    Tian, A.; Degeling, A. W.

    2017-12-01

    Simulations and observations had shown that single positive/negative solar wind dynamic pressure pulse would excite geomagnetic impulsive events along with ionosphere and/or magnetosphere vortices which are connected by field aligned currents(FACs). In this work, a large scale ( 9min) magnetic hole event in solar wind provided us with the opportunity to study the effects of positive-negative pulse pair (△p/p 1) on the magnetosphere and ionosphere. During the magnetic hole event, two traveling convection vortices (TCVs, anti-sunward) first in anticlockwise then in clockwise rotation were detected by geomagnetic stations located along the 10:30MLT meridian. At the same time, another pair of ionospheric vortices azimuthally seen up to 3 MLT first in clockwise then in counter-clockwise rotation were also appeared in the afternoon sector( 14MLT) and centered at 75 MLAT without obvious tailward propagation feature. The duskside vortices were also confirmed in SuperDARN radar data. We simulated the process of magnetosphere struck by a positive-negative pulse pair and it shows that a pair of reversed flow vortices in the magnetosphere equatorial plane appeared which may provide FACs for the vortices observed in ionosphere. Dawn dusk asymmetry of the vortices as well as the global geomagnetism perturbation characteristics were also discussed.

  18. Tolerances on MLC leaf position accuracy for IMRT delivery with a dynamic MLC

    International Nuclear Information System (INIS)

    Rangel, Alejandra; Dunscombe, Peter

    2009-01-01

    The objective determination of performance standards for radiation therapy equipment requires, ideally, establishing the quantitative relationship between performance deviations and clinical outcome or some acceptable surrogate. In this simulation study the authors analyzed the dosimetric impact of random (leaf by leaf) and systematic (entire leaf bank) errors in the position of the MLC leaves on seven clinical prostate and seven clinical head and neck IMRT plans delivered using a dynamic MLC. In-house software was developed to incorporate normally distributed errors of up to ±2 mm in individual leaf position or systematic errors (±1 and ±0.5 mm in all leaves of both leaf banks or +1 mm in one bank only) into the 14 plans, thus simulating treatment delivery using a suboptimally performing MLC. The dosimetric consequences of suboptimal MLC performance were quantified using the equivalent uniform doses (EUDs) of the clinical target volumes and important organs at risk (OARs). The deviation of the EUDs of the selected structures as the performance of the MLC deteriorated was used as the objective surrogate of clinical outcome. Random errors of 2 mm resulted in negligible changes for all structures of interest in both sites. In contrast, systematic errors can lead to potentially significant dosimetric changes that may compromise clinical outcome. If a 2% change in EUD of the target and 2 Gy for the OARs were adopted as acceptable levels of deviation in dose due to MLC effects alone, then systematic errors in leaf position will need to be limited to 0.3 mm. This study provides guidance, based on a dosimetric surrogate of clinical outcome, for the development of one component, leaf position accuracy of performance standards for multileaf collimators.

  19. Robust H∞ Control of Neutral System with Time-Delay for Dynamic Positioning Ships

    Directory of Open Access Journals (Sweden)

    Dawei Zhao

    2015-01-01

    Full Text Available Due to the input time-delay existing in most thrust systems of the ships, the robust H∞ controller is designed for the ship dynamic positioning (DP system with time-delay. The input delay system is turned to a neutral time-delay system by a state-derivative control law. The less conservative result is derived for the neutral system with state-derivative feedback by the delay-decomposition approach and linear matrix inequality (LMI. Finally, the numerical simulations demonstrate the asymptotic stability and robustness of the controller and verify that the designed DP controller is effective in the varying environment disturbances of wind, waves, and ocean currents.

  20. Social positions, scripts, and functioning dynamics: phenomenology of the Egyptian social unconscious.

    Science.gov (United States)

    Taha, Mohamed

    2014-07-01

    This article explores the constituents, components, and manifestations of the Egyptian social unconscious. Noting that Bion's group basic assumptions are actually based on Klein's individual psychic positions (Paranoid-Schizoid and Depressive; PS-D), and can easily be extrapolated to the social large group, the author assumes that to communities, societies, and cultures the same assumptions may apply to some extent. Moreover, just as groups can move between basic assumption functioning and work functioning, so societies seem to do. Eric Berne's concept of an "individual life script" can also be extended to societies that can have a "social life script." This article is a step toward designing a "social unconscious" map for different countries and cultures that shows where on the PS-D spectrum a certain country is placed, what is a certain culture's "social life script," and how the dynamics of a certain society can be manifested in its people's behavior as either basic assumption or work functioning.

  1. Existence of positive solutions for semipositone dynamic system on time scales

    Directory of Open Access Journals (Sweden)

    You-Wei Zhang

    2008-08-01

    Full Text Available In this paper, we study the following semipositone dynamic system on time scales $$displaylines{ -x^{DeltaDelta}(t=f(t,y+p(t, quad tin(0,T_{mathbb{T}},cr -y^{DeltaDelta}(t=g(t,x, quad tin(0,T_{mathbb{T}},cr x(0=x(sigma^{2}(T=0, cr alpha{y(0}-eta{y^{Delta}{(0}}= gamma{y(sigma(T}+delta{y^{Delta}(sigma(T}=0. }$$ Using fixed point index theory, we show the existence of at least one positive solution. The interesting point is the that nonlinear term is allowed to change sign and may tend to negative infinity.

  2. Spatially explicit simulation of peatland hydrology and carbon dioxide exchange: Influence of mesoscale topography

    Science.gov (United States)

    Sonnentag, O.; Chen, J. M.; Roulet, N. T.; Ju, W.; Govind, A.

    2008-06-01

    Carbon dynamics in peatlands are controlled, in large part, by their wetness as defined by water table depth and volumetric liquid soil moisture content. A common type of peatland is raised bogs that typically have a multiple-layer canopy of vascular plants over a Sphagnum moss ground cover. Their convex form restricts water supply to precipitation and water is shed toward the margins, usually by lateral subsurface flow. The hydraulic gradient for lateral subsurface flow is governed by the peat surface topography at the mesoscale (˜200 m to 5 km). To investigate the influence of mesoscale topography on wetness, evapotranspiration (ET), and gross primary productivity (GPP) in a bog during the snow-free period, we compare the outputs of a further developed version of the daily Boreal Ecosystem Productivity Simulator (BEPS) with observations made at the Mer Bleue peatland, located near Ottawa, Canada. Explicitly considering mesoscale topography, simulated total ET and GPP correlate well with measured ET (r = 0.91) and derived gross ecosystem productivity (GEP; r = 0.92). Both measured ET and derived GEP are simulated similarly well when mesoscale topography is neglected, but daily simulated values are systematically underestimated by about 10% and 12% on average, respectively, due to greater wetness resulting from the lack of lateral subsurface flow. Owing to the differences in moss surface conductances of water vapor and carbon dioxide with increasing moss water content, the differences in the spatial patterns of simulated total ET and GPP are controlled by the mesotopographic position of the moss ground cover.

  3. Dynamic Characteristics of Positive Pulsed Dielectric Barrier Discharge for Ozone Generation in Air

    Science.gov (United States)

    Wei, Linsheng; Peng, Bangfa; Li, Ming; Zhang, Yafang; Hu, Zhaoji

    2016-02-01

    A comprehensive dynamic model consisting of 66 reactions and 24 species is developed to investigate the dynamic characteristics of ozone generation by positive pulsed dielectric barrier discharge (DBD) using parallel-plate reactor in air. The electron energy conservation equation is coupled to the electron continuity equation, the heavy species continuity equation, and Poisson's equation for a better description. The reliability of the model is experimentally confirmed. The model can be used to predict the temporal and spatial evolution of species, as well as streamer propagation. The simulation results show that electron density increases nearly exponentially in the direction to the anode at the electron avalanche. Streamer propagation velocity is about 5.26 × 104 m/s from anode to cathode in the simulated condition. The primary positive ion, negative ion, and excited species are O2+, O3- and O2(1Δg) in pulsed DBD in air, respectively. N2O has the largest density among nitrogen oxides. e and N2+ densities in the streamer head increase gradually to maximum values with the development of the streamer. Meanwhile, the O2+, O, O3, N2(A3Σ) and N2O densities reach maximum values in the vicinity of the anode. supported by National Natural Science Foundation of China (Nos. 51366012 and 11105067), Jiangxi Province Young Scientists (Jinggang Star) Cultivation Plan of China (No. 20133BCB23008), Natural Science Foundation of Jiangxi, China (No. 20151BAB206047) and Jiangxi Province Higher School Science and Technology Landing Plan of China (No. KJLD-14015)

  4. Soil Redox Dynamics Vary with Landscape Position and Hydroperiod in the Pantanal Wetland Ecosystem

    Science.gov (United States)

    Couto, E. G.; Johnson, M. S.; Pinto-jr, O.; Leite, N. K.

    2012-12-01

    The Pantanal wetland ecosystem of central South America is the largest tropical wetland complex in the world. Nevertheless, biogeochemistry in the Pantanal is quite limited. A unimodal precipitation regime averages approximately 1200 mm y-1 during the six-month rainy season, leading to seasonal flooding on much, but not all, of the landscape. We investigated the impact of landscape position and hydroperiod on soil redox potential (Eh) in four research locations in the Northern Pantanal near Poconé, Mato Grosso: two locations subject to flooding (a flooded forest and a flooded scrub forest) and two locations with infrequent surface flooding (tree islands known as cordilheiras). Redox sensors were installed at 10 cm and 30 cm depths at each of the four locations with half-hourly data recorded over all hydro-periods (dry season, rising water, flood and falling water). Here we summarize results to date in this ongoing study. Reducing conditions were observed in response to both precipitation events saturating soil from the surface downward, as well as in response to regional flooding dynamics that saturate soil from below. These are helping to guide design of a study on methane dynamics in the Pantanal wetland complex.

  5. Position sensitive regions in a generic radiation sensor based on single event upsets in dynamic RAMs

    International Nuclear Information System (INIS)

    Darambara, D.G.; Spyrou, N.M.

    1997-01-01

    Modern integrated circuits are highly complex systems and, as such, are susceptible to occasional failures. Semiconductor memory devices, particularly dynamic random access memories (dRAMs), are subject to random, transient single event upsets (SEUs) created by energetic ionizing radiation. These radiation-induced soft failures in the stored data of silicon based memory chips provide the foundation for a new, highly efficient, low cost generic radiation sensor. The susceptibility and the detection efficiency of a given dRAM device to SEUs is a complicated function of the circuit design and geometry, the operating conditions and the physics of the charge collection mechanisms involved. Typically, soft error rates measure the cumulative response of all sensitive regions of the memory by broad area chip exposure in ionizing radiation environments. However, this study shows that many regions of a dynamic memory are competing charge collection centres having different upset thresholds. The contribution to soft fails from discrete regions or individual circuit elements of the memory device is unambiguously separated. Hence the use of the dRAM as a position sensitive radiation detector, with high spatial resolution, is assessed and demonstrated. (orig.)

  6. Surface Micro Topography Replication in Injection Moulding

    DEFF Research Database (Denmark)

    Arlø, Uffe Rolf; Hansen, Hans Nørgaard; Kjær, Erik Michael

    2005-01-01

    The surface micro topography of injection moulded plastic parts can be important for aesthetical and technical reasons. The quality of replication of mould surface topography onto the plastic surface depends among other factors on the process conditions. A study of this relationship has been...... carried out with rough EDM (electrical discharge machining) mould surfaces, a PS grade, and by applying established three-dimensional topography parameters. Significant quantitative relationships between process parameters and topography parameters were established. It further appeared that replication...

  7. Rapid Evaluation for Position-Dependent Dynamics of a 3-DOF PKM Module

    Directory of Open Access Journals (Sweden)

    Hai-wei Luo

    2014-08-01

    Full Text Available Based on the substructure synthesis and modal reduction technique, a computationally efficient elastodynamic model for a fully flexible 3-RPS parallel kinematic machine (PKM tool is proposed, in which the frequency response function (FRF at the end of the tool can be obtained at any given position throughout its workspace. In the proposed elastodynamic model, the whole system is divided into a moving platform subsystem and three identical RPS limb subsystems, in which all joint compliances are included. The spherical joint and the revolute joint are treated as lumped virtual springs with equal stiffness; the platform is treated as a rigid body and the RPS limbs are modelled with modal reduction techniques. With the compatibility conditions at interfaces between the limbs and the platform, an analytical system governing differential equation is derived. Based on the derived model, the position-dependent dynamic characteristics such as natural frequencies, mode shapes, and FRFs of the 3-RPS PKM are simulated. The simulation results indicate that the distributions of natural frequencies throughout the workspace are strongly dependant on mechanism's configurations and demonstrate an axial-symmetric tendency. The following finite element analysis and modal tests both validate the analytical results of natural frequencies, mode shapes, and the FRFs.

  8. Systems approach to studying animal sociality: individual position versus group organization in dynamic social network models.

    Directory of Open Access Journals (Sweden)

    Karlo Hock

    2010-12-01

    Full Text Available Social networks can be used to represent group structure as a network of interacting components, and also to quantify both the position of each individual and the global properties of a group. In a series of simulation experiments based on dynamic social networks, we test the prediction that social behaviors that help individuals reach prominence within their social group may conflict with their potential to benefit from their social environment. In addition to cases where individuals were able to benefit from improving both their personal relative importance and group organization, using only simple rules of social affiliation we were able to obtain results in which individuals would face a trade-off between these factors. While selection would favor (or work against social behaviors that concordantly increase (or decrease, respectively fitness at both individual and group level, when these factors conflict with each other the eventual selective pressure would depend on the relative returns individuals get from their social environment and their position within it. The presented results highlight the importance of a systems approach to studying animal sociality, in which the effects of social behaviors should be viewed not only through the benefits that those provide to individuals, but also in terms of how they affect broader social environment and how in turn this is reflected back on an individual's fitness.

  9. Spin dynamics of the itinerant helimagnet MnSi studied by positive muon spin relaxation

    International Nuclear Information System (INIS)

    Kadono, R.; Matsuzaki, T.; Yamazaki, T.; Kreitzman, S.R.; Brewer, J.H.

    1990-03-01

    The local magnetic fields and spin dynamics of the itinerant helimagnet MnSi(T c ≅ 29.5 K) have been studied experimentally using positive muon spin rotation/relaxation (μ + SR) methods. In the ordered phase (T c ), zero-field μSR was used to measure the hyperfine fields at the muon sites as well as the muon spin-lattice relaxation time T 1 μ . Two magnetically inequivalent interstitial μ + sites were found with hyperfine coupling constants A hf (1) = -3.94 kOe/μ B and A hf (2) = -6.94 kOe/μ B , respectively. In the paramagnetic phase (T > T c ), the muon-nuclear spin double relaxation technique was used to simultaneously but independently determine the spin-lattice relaxation time T 1 Mn of 55 Mn spins and that of positive muons (T 1 μ ) over a wide temperature range (T c 1 Mn and T 1 μ in both phases shows systematic deviations from the predictions of self-consistent renormalization (SCR) theory. (author)

  10. Mandibular position influence on pilots' postural balance analyzed under dynamic conditions.

    Science.gov (United States)

    Baldini, Alberto; Nota, Alessandro; Cioffi, Clementina; Ballanti, Fabiana; Tecco, Simona

    2017-11-01

    The aim of this study is to evaluate the influence of the mandibular position on the postural stability in a sample of civilian and military pilots. Twenty military pilots (males, mean age 35.15 ± 3.14 years) and 17 civilian pilots (males, mean 34.91 ± 2.15 years) were enrolled in this study and underwent a Sensory Organization Test (SOT) using the EquiTest® (NeuroCom International Inc., Clackamas, OR, USA) computerized dynamic posturography. The composite parameter was recorded and analyzed. The equilibrium score (ES) recorded in centric occlusion is slightly higher than the ES recorded in mandibular rest position; civilian pilots showed ESs slightly higher than military pilots. The two-way ANOVA analysis shows these differences are not statistically significant. The findings of this study seem to suggest that the composite parameter of the SOT is not sensitive in analyzing the influence of the stomatognathic system on the postural balance of civilian and military pilots.

  11. Dynamic loop gain increases upon adopting the supine body position during sleep in patients with obstructive sleep apnoea.

    Science.gov (United States)

    Joosten, Simon A; Landry, Shane A; Sands, Scott A; Terrill, Philip I; Mann, Dwayne; Andara, Christopher; Skuza, Elizabeth; Turton, Anthony; Berger, Philip; Hamilton, Garun S; Edwards, Bradley A

    2017-11-01

    Obstructive sleep apnoea (OSA) is typically worse in the supine versus lateral sleeping position. One potential factor driving this observation is a decrease in lung volume in the supine position which is expected by theory to increase a key OSA pathogenic factor: dynamic ventilatory control instability (i.e. loop gain). We aimed to quantify dynamic loop gain in OSA patients in the lateral and supine positions, and to explore the relationship between change in dynamic loop gain and change in lung volume with position. Data from 20 patients enrolled in previous studies on the effect of body position on OSA pathogenesis were retrospectively analysed. Dynamic loop gain was calculated from routinely collected polysomnographic signals using a previously validated mathematical model. Lung volumes were measured in the awake state with a nitrogen washout technique. Dynamic loop gain was significantly higher in the supine than in the lateral position (0.77 ± 0.15 vs 0.68 ± 0.14, P = 0.012). Supine functional residual capacity (FRC) was significantly lower than lateral FRC (81.0 ± 15.4% vs 87.3 ± 18.4% of the seated FRC, P = 0.021). The reduced FRC we observed on moving to the supine position was predicted by theory to increase loop gain by 10.2 (0.6, 17.1)%, a value similar to the observed increase of 8.4 (-1.5, 31.0)%. Dynamic loop gain increased by a small but statistically significant amount when moving from the lateral to supine position and this may, in part, contribute to the worsening of OSA in the supine sleeping position. © 2017 Asian Pacific Society of Respirology.

  12. Water balance and topography predict fire and forest structure patterns

    Science.gov (United States)

    Van R. Kane; James A. Lutz; C. Alina Cansler; Nicholas A. Povak; Derek J. Churchill; Douglas F. Smith; Jonathan T. Kane; Malcolm P. North

    2015-01-01

    Mountainous topography creates fine-scale environmental mosaics that vary in precipitation, temperature, insolation, and slope position. This mosaic in turn influences fuel accumulation and moisture and forest structure. We studied these the effects of varying environmental conditions across a 27,104 ha landscape within Yosemite National Park, California, USA, on the...

  13. Stresses in a submarine topography under ocean waves

    Energy Technology Data Exchange (ETDEWEB)

    Mei, C.C.; McTigue, D.F.

    1984-01-01

    The problem of submarine slope stability is of interest to both offshore engineering and geology. In an uneven topography, 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 dynamic 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 topography under sea waves. Sample results are given for a ridge and a canyon. In particular the dynamic pore pressure and the combined static and dynamic effective stresses are presented. 10 references, 11 figures.

  14. Stresses in a submarine topography under ocean waves

    Energy Technology Data Exchange (ETDEWEB)

    Mei, C.C.; McTigue, D.F.

    1984-09-01

    The problem of submarine slope stability is of interest to both offshore engineering and geology. In an uneven topography, 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 dynamic 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 topography under sea waves. Sample results are given for a ridge and a canyon. In particular, the dynamic pore pressure and the combined static and dynamic effective stresses are presented.

  15. Positive responses of belowground C dynamics to nitrogen enrichment in China.

    Science.gov (United States)

    Deng, Lei; Peng, Changhui; Zhu, Guangyu; Chen, Lei; Liu, Yulin; Shangguan, Zhouping

    2018-03-01

    Determining how nitrogen (N) impacts ecosystem carbon (C) cycling is critical to using C sequestration to offset anthropogenic CO 2 emissions. The N deposition rate in China is higher than the global average; however, many results of N enrichment experiments in China have not been included in global syntheses. In this study, we assembled a large dataset that comprised 124 published studies concerning N addition experiments, including 570 observations at 127 sites across China, to quantify the responses of belowground C dynamics to N enrichment in terrestrial ecosystems in China by a meta-analysis. The results showed that overall soil organic C, dissolved organic C (DOC) and soil microbial biomass C (MBC) increased by 1.8, 7.4, and 8.8%, respectively (Penrichment; belowground biomass and litter increased by 14.6 and 24.4%, respectively (Penrichment promoted C inputs into the soil mainly by increasing litter and belowground biomass inputs. Additionally, N enrichment increased C output by increasing soil respiration. Land use type and N addition level had different impacts on the soil C pool and on soil respiration. DOC, MBC, and litter exhibited more positive responses to N deposition in cooler and more arid regions than in other regions. The meta-analysis indicated that N enrichment had a positive impact on belowground C cycles in China. Climate played a greater role than did N deposition level in affecting processes of ecosystem C cycling. Moreover, belowground C cycle processes are determined by complicated interactions among land use type, N enrichment, and climate. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Remote handling dynamical modelling: assessment on new approach to enhance positioning accuracy with heavy load manipulation

    International Nuclear Information System (INIS)

    Gagarina-Sasia, T.; David, O.; Dubus, G.; Perrot, Y.; Riwain, A.

    2007-01-01

    In vessel maintenance work in Fusion Tokamak will be carried out with help several sets of robotic devices. Heavy loads handling in constrained space is identified by all players of the RH community as a key-issue in the latest Fusion Tokamak facilities. To deal with high-level dexterity tasks, high payload to mass ratio and limited operating space, RH equipment designers can only propose systems whose mechanical flexibility is no longer negligible and need to be taken into account in the control scheme. Traditional approaches where control system only includes a linear model of deformation of the structure leads to poor positioning accuracy. Uncontrolled or under evaluated errors could be damaging for in-vessel components during maintenance operations in the Tokamak facility. To address the control of complex flexible systems, we will investigate the use of specific mechanical software that combines both finite element and kinematical joints analyses, with a strong-coupled formulation, to perform system dynamics simulations. This procedure will be applied on a single axis mock up robotic joint with highly flexible structure. A comparison of experimental results with the traditional linear approach and the specified software model will be carried out. Benefits introduced by this new approach will finally be assessed in view of RH design or specification in the field of RH in Fusion Tokamak scale such as ITER. (orig.)

  17. Huntingtin coordinates the dynein-mediated dynamic positioning of endosomes and lysosomes

    Science.gov (United States)

    Caviston, Juliane P.; Zajac, Allison L.; Tokito, Mariko; Holzbaur, Erika L.F.

    2011-01-01

    Huntingtin (Htt) is a membrane-associated scaffolding protein that interacts with microtubule motors as well as actin-associated adaptor molecules. We examined a role for Htt in the dynein-mediated intracellular trafficking of endosomes and lysosomes. In HeLa cells depleted of either Htt or dynein, early, recycling, and late endosomes (LE)/lysosomes all become dispersed. Despite altered organelle localization, kinetic assays indicate only minor defects in intracellular trafficking. Expression of full-length Htt is required to restore organelle localization in Htt-depleted cells, supporting a role for Htt as a scaffold that promotes functional interactions along its length. In dynein-depleted cells, LE/lysosomes accumulate in tight patches near the cortex, apparently enmeshed by cortactin-positive actin filaments; Latrunculin B-treatment disperses these patches. Peripheral LE/lysosomes in dynein-depleted cells no longer colocalize with microtubules. Htt may be required for this off-loading, as the loss of microtubule association is not seen in Htt-depleted cells or in cells depleted of both dynein and Htt. Inhibition of kinesin-1 relocalizes peripheral LE/lysosomes induced by Htt depletion but not by dynein depletion, consistent with their detachment from microtubules upon dynein knockdown. Together, these data support a model of Htt as a facilitator of dynein-mediated trafficking that may regulate the cytoskeletal association of dynamic organelles. PMID:21169558

  18. Corneal topography with an aberrometry-topography system.

    Science.gov (United States)

    Mülhaupt, Michael; Dietzko, Sven; Wolffsohn, James; Bandlitz, Stefan

    2018-05-07

    To investigate the agreement between the central corneal radii and corneal eccentricity measurements generated by the new Wave Analyzer 700 Medica (WAV) compared to the Keratograph 4 (KER) and to test the repeatability of the instruments. 20 subjects (10 male, mean age 29.1 years, range 21-50 years) were recruited from the students and staff of the Cologne School of Optometry. Central corneal radii for the flat (r c/fl ) and steep (r c/st ) meridian as well as corneal eccentricity for the nasal (e nas ), temporal (e temp ), inferior (e inf ) and superior (e sup ) directions were measured using WAV and KER by one examiner in a randomized order. Central radii of the flat (r c/fl ) and steep (r c/st ) meridian measured with both instruments were statically significantly correlated (r = 0.945 and r = 0.951; p  0.05). Limits of agreement (LoA) indicate a better repeatability for the KER compared to WAV. Corneal topography measurements captured with the WAV were strongly correlated with the KER. However, due to the differences in measured corneal radii and eccentricities, the devices cannot be used interchangeably. For corneal topography the KER demonstrated better repeatability. Copyright © 2018 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  19. Microdefects in an as-grown Czochralski silicon crystal studied by synchrotron radiation section topography with aid of computer simulation

    International Nuclear Information System (INIS)

    Iida, Satoshi; Aoki, Yoshirou; Okitsu, Kouhei; Sugita, Yoshimitsu; Kawata, Hiroshi; Abe, Takao

    1998-01-01

    Grown-in microdefects of a Czochralski (CZ) silicon crystal grown at a slow growth rate were studied by section topography using high energy synchrotron radiation. Images of the microdefects in the section topographs were analyzed quantitatively using computer simulation based on the Takagi-Taupin type dynamical diffraction theory of X-rays, and reproduced successfully by the simulation when the microdefects were assumed to be spherical strain centers. Sizes and positions of the microdefects were able to be determined by detailed comparison between the experiments and the computer simulations. The validity of the computer simulation in an analysis of the section topographs is discussed. (author)

  20. Cross-cultural patterns in dynamic ratings of positive and negative natural emotional behaviour.

    Science.gov (United States)

    Sneddon, Ian; McKeown, Gary; McRorie, Margaret; Vukicevic, Tijana

    2011-02-18

    Studies of cross-cultural variations in the perception of emotion have typically compared rates of recognition of static posed stimulus photographs. That research has provided evidence for universality in the recognition of a range of emotions but also for some systematic cross-cultural variation in the interpretation of emotional expression. However, questions remain about how widely such findings can be generalised to real life emotional situations. The present study provides the first evidence that the previously reported interplay between universal and cultural influences extends to ratings of natural, dynamic emotional stimuli. Participants from Northern Ireland, Serbia, Guatemala and Peru used a computer based tool to continuously rate the strength of positive and negative emotion being displayed in twelve short video sequences by people from the United Kingdom engaged in emotional conversations. Generalized additive mixed models were developed to assess the differences in perception of emotion between countries and sexes. Our results indicate that the temporal pattern of ratings is similar across cultures for a range of emotions and social contexts. However, there are systematic differences in intensity ratings between the countries, with participants from Northern Ireland making the most extreme ratings in the majority of the clips. The results indicate that there is strong agreement across cultures in the valence and patterns of ratings of natural emotional situations but that participants from different cultures show systematic variation in the intensity with which they rate emotion. Results are discussed in terms of both 'in-group advantage' and 'display rules' approaches. This study indicates that examples of natural spontaneous emotional behaviour can be used to study cross-cultural variations in the perception of emotion.

  1. Cross-cultural patterns in dynamic ratings of positive and negative natural emotional behaviour.

    Directory of Open Access Journals (Sweden)

    Ian Sneddon

    2011-02-01

    Full Text Available Studies of cross-cultural variations in the perception of emotion have typically compared rates of recognition of static posed stimulus photographs. That research has provided evidence for universality in the recognition of a range of emotions but also for some systematic cross-cultural variation in the interpretation of emotional expression. However, questions remain about how widely such findings can be generalised to real life emotional situations. The present study provides the first evidence that the previously reported interplay between universal and cultural influences extends to ratings of natural, dynamic emotional stimuli.Participants from Northern Ireland, Serbia, Guatemala and Peru used a computer based tool to continuously rate the strength of positive and negative emotion being displayed in twelve short video sequences by people from the United Kingdom engaged in emotional conversations. Generalized additive mixed models were developed to assess the differences in perception of emotion between countries and sexes. Our results indicate that the temporal pattern of ratings is similar across cultures for a range of emotions and social contexts. However, there are systematic differences in intensity ratings between the countries, with participants from Northern Ireland making the most extreme ratings in the majority of the clips.The results indicate that there is strong agreement across cultures in the valence and patterns of ratings of natural emotional situations but that participants from different cultures show systematic variation in the intensity with which they rate emotion. Results are discussed in terms of both 'in-group advantage' and 'display rules' approaches. This study indicates that examples of natural spontaneous emotional behaviour can be used to study cross-cultural variations in the perception of emotion.

  2. IMPLEMENTATION APPROACHES DURING SIMULATION OF ENERGY PROCESSES FOR A DYNAMICALLY POSITIONED SHIP

    Directory of Open Access Journals (Sweden)

    V.V. Budashko

    2015-12-01

    Full Text Available Purpose. Creation of a mathematical model of the ship's power plant (SPP combined propulsion complexes (CPC that takes into account the behavior of all objects, including the ship itself, the transfer of power from the medium speed diesel generators on the propellers, which will allow to take into account the hydrodynamic properties of the vessel and their impact on the energy processes in SPP CPC. Methodology. The analysis of energy processes in the SPP CPC in different operating conditions resulted in creation of a strategy for constructing mathematical models of SPP CPC. This strategy is based on the implementation on the vector plane resulting power characteristics of SPP vectors disturbances, leading to the deviation of the hydrodynamic characteristics of the ship during operation dynamic positioning. The result allowed to consider not only the features of setting PID-governors of frequency converters of electric thrusters but the automatic voltage regulators of medium speed diesel generators as well. Results. Within the research work a software package Ships_CPC in MatLab/Simulink was developed under the state budget project «Concepts, technologies and ways of improving ship power plants combined propulsion complexes» at the Department of Electromechanics and Electrical Engineering of Odessa National Maritime Academy. Originality. This complex represents a set of functional blocks of the components SPP CPC, built on the principle of «input-output». The simulation results demonstrate the ability to use software package Ships_CPC to study the effect of various settings on the energy regulators of processes SPP CPC, which can develop and integrate the different strategies of automatic voltage regulators. Practical value. Since software complex Ships_CPC was developed under Open system technology, it can reorganize, re-tune and integrate in processes of any difficulties with further completion in the form of a universal structure.

  3. Photogrammetric portrayal of Mars topography.

    Science.gov (United States)

    Wu, S.S.C.

    1979-01-01

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

  4. Bayesian integration of position and orientation cues in perception of biological and non-biological dynamic forms

    Directory of Open Access Journals (Sweden)

    Steven Matthew Thurman

    2014-02-01

    Full Text Available Visual form analysis is fundamental to shape perception and likely plays a central role in perception of more complex dynamic shapes, such as moving objects or biological motion. Two primary form-based cues serve to represent the overall shape of an object: the spatial position and the orientation of locations along the boundary of the object. However, it is unclear how the visual system integrates these two sources of information in dynamic form analysis, and in particular how the brain resolves ambiguities due to sensory uncertainty and/or cue conflict. In the current study, we created animations of sparsely-sampled dynamic objects (human walkers or rotating squares comprised of oriented Gabor patches in which orientation could either coincide or conflict with information provided by position cues. When the cues were incongruent, we found a characteristic trade-off between position and orientation information whereby position cues increasingly dominated perception as the relative uncertainty of orientation increased and vice versa. Furthermore, we found no evidence for differences in the visual processing of biological and non-biological objects, casting doubt on the claim that biological motion may be specialized in the human brain, at least in specific terms of form analysis. To explain these behavioral results quantitatively, we adopt a probabilistic template-matching model that uses Bayesian inference within local modules to estimate object shape separately from either spatial position or orientation signals. The outputs of the two modules are integrated with weights that reflect individual estimates of subjective cue reliability, and integrated over time to produce a decision about the perceived dynamics of the input data. Results of this model provided a close fit to the behavioral data, suggesting a mechanism in the human visual system that approximates rational Bayesian inference to integrate position and orientation signals in dynamic

  5. Measurement and inference of profile soil-water dynamics at different hillslope positions in a semiarid agricultural watershed

    Science.gov (United States)

    Green, Timothy R.; Erskine, Robert H.

    2011-12-01

    Dynamics of profile soil water vary with terrain, soil, and plant characteristics. The objectives addressed here are to quantify dynamic soil water content over a range of slope positions, infer soil profile water fluxes, and identify locations most likely influenced by multidimensional flow. The instrumented 56 ha watershed lies mostly within a dryland (rainfed) wheat field in semiarid eastern Colorado. Dielectric capacitance sensors were used to infer hourly soil water content for approximately 8 years (minus missing data) at 18 hillslope positions and four or more depths. Based on previous research and a new algorithm, sensor measurements (resonant frequency) were rescaled to estimate soil permittivity, then corrected for temperature effects on bulk electrical conductivity before inferring soil water content. Using a mass-conservation method, we analyzed multitemporal changes in soil water content at each sensor to infer the dynamics of water flux at different depths and landscape positions. At summit positions vertical processes appear to control profile soil water dynamics. At downslope positions infrequent overland flow and unsaturated subsurface lateral flow appear to influence soil water dynamics. Crop water use accounts for much of the variability in soil water between transects that are either cropped or fallow in alternating years, while soil hydraulic properties and near-surface hydrology affect soil water variability across landscape positions within each management zone. The observed spatiotemporal patterns exhibit the joint effects of short-term hydrology and long-term soil development. Quantitative methods of analyzing soil water patterns in space and time improve our understanding of dominant soil hydrological processes and provide alternative measures of model performance.

  6. Wave packet dynamics for a system with position and time-dependent effective mass in an infinite square well

    Energy Technology Data Exchange (ETDEWEB)

    Vubangsi, M.; Tchoffo, M.; Fai, L. C. [Mesoscopic and Multilayer Structures Laboratory, Physics Department, University of Dschang, P.O. Box 417 Dschang (Cameroon); Pisma’k, Yu. M. [Department of Theoretical Physics, Saint Petersburg State University, Saint Petersburg (Russian Federation)

    2015-12-15

    The problem of a particle with position and time-dependent effective mass in a one-dimensional infinite square well is treated by means of a quantum canonical formalism. The dynamics of a launched wave packet of the system reveals a peculiar revival pattern that is discussed. .

  7. Multiscale Study of Currents Affected by Topography

    Science.gov (United States)

    2015-09-30

    1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Multiscale Study of Currents Affected by Topography ...the effects of topography on the ocean general and regional circulation with a focus on the wide range of scales of interactions. The small-scale...details of the topography and the waves, eddies, drag, and turbulence it generates (at spatial scales ranging from meters to mesoscale) interact in the

  8. An Approach for High-precision Stand-alone Positioning in a Dynamic Environment

    Science.gov (United States)

    Halis Saka, M.; Metin Alkan, Reha; Ozpercin, Alişir

    2015-04-01

    In this study, an algorithm is developed for precise positioning in dynamic environment utilizing a single geodetic GNSS receiver using carrier phase data. In this method, users should start the measurement on a known point near the project area for a couple of seconds making use of a single dual-frequency geodetic-grade receiver. The technique employs iono-free carrier phase observations with precise products. The equation of the algorithm is given below; Sm(t(i+1))=SC(ti)+[ΦIF (t(i+1) )-ΦIF (ti)] where, Sm(t(i+1)) is the phase-range between satellites and the receiver, SC(ti) is the initial range computed from the initial known point coordinates and the satellite coordinates and ΦIF is the ionosphere-free phase measurement (in meters). Tropospheric path delays are modelled using the standard tropospheric model. To accomplish the process, an in-house program was coded and some functions were adopted from Easy-Suite available at http://kom.aau.dk/~borre/easy. In order to assess the performance of the introduced algorithm in a dynamic environment, a dataset from a kinematic test measurement was used. The data were collected from a kinematic test measurement in Istanbul, Turkey. In the test measurement, a geodetic dual-frequency GNSS receiver, Ashtech Z-Xtreme, was set up on a known point on the shore and a couple of epochs were recorded for initialization. The receiver was then moved to a vessel and data were collected for approximately 2.5 hours and the measurement was finalized on a known point on the shore. While the kinematic measurement on the vessel were carried out, another GNSS receiver was set up on a geodetic point with known coordinates on the shore and data were collected in static mode to calculate the reference trajectory of the vessel using differential technique. The coordinates of the vessel were calculated for each measurement epoch with the introduced method. With the purpose of obtaining more robust results, all coordinates were calculated

  9. Jumping for Joy: The Importance of the Body and of Dynamics in the Expression and Recognition of Positive Emotions

    Directory of Open Access Journals (Sweden)

    Marcello Mortillaro

    2018-05-01

    Full Text Available The majority of research on emotion expression has focused on static facial prototypes of a few selected, mostly negative emotions. Implicitly, most researchers seem to have considered all positive emotions as sharing one common signal (namely, the smile, and consequently as being largely indistinguishable from each other in terms of expression. Recently, a new wave of studies has started to challenge the traditional assumption by considering the role of multiple modalities and the dynamics in the expression and recognition of positive emotions. Based on these recent studies, we suggest that positive emotions are better expressed and correctly perceived when (a they are communicated simultaneously through the face and body and (b perceivers have access to dynamic stimuli. Notably, we argue that this improvement is comparatively more important for positive emotions than for negative emotions. Our view is that the misperception of positive emotions has fewer immediate and potentially life-threatening consequences than the misperception of negative emotions; therefore, from an evolutionary perspective, there was only limited benefit in the development of clear, quick signals that allow observers to draw fine distinctions between them. Consequently, we suggest that the successful communication of positive emotions requires a stronger signal than that of negative emotions, and that this signal is provided by the use of the body and the way those movements unfold. We hope our contribution to this growing field provides a new direction and a theoretical grounding for the many lines of empirical research on the expression and recognition of positive emotions.

  10. DMPD: Cellular reprogramming by gram-positive bacterial components: a review. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 16885502 Cellular reprogramming by gram-positive bacterial components: a review. Bu...(.csml) Show Cellular reprogramming by gram-positive bacterial components: a review. PubmedID 16885502 Title... Cellular reprogramming by gram-positive bacterial components: a review. Authors

  11. Effect of Recumbent Body Positions on Dynamic Lung Function Parameters in Healthy Young Subjects.

    Science.gov (United States)

    Pal, Arvind Kumar; Tiwari, Sunita; Verma, Dileep Kumar

    2017-05-01

    The change in body position can alter pulmonary functions parameters, therefore it is important to understand the physiological basis of these alteration. Ideally, spirometry is done in sitting position until the subject is unable to do so. Hospitalized patients often assume recumbent body positions irrespective of underlying pathology. Hence, need arises to find out best recumbent body positions for the benefit of these patients to make breathing comfortable for them. The aim of this study was to find out whether the change from the supine position to crook lying and Fowler's position (45° dorsal elevation) causes change in spirometric parameters. The present work was carried out at Department of Physiology, King George's Medical University, Lucknow. A total 131 apparently healthy individuals were enrolled in this cross-sectional study. Lung function was assessed using a PC-based spirometer according to American Thoracic Society guideline in the supine, crook lying and Fowler's position (45° dorsal elevation). The study consisted of 131 subjects (male 66%, female 34%), with mean age of 20.15±2.71 years and BMI 21.20±3.28 Kg/m 2 . Repeated measures ANOVA with post hoc Bonferroni test was used to compare the mean values between each body position. Compared with the other two positions, Fowler's position showed significantly (p<0.05) higher values for FVC, FEV 1 , PEF, FEF 25-75% . Recumbent body position influences spirometric parameters in young healthy subjects. We demonstrated that spirometric values are higher in the Fowler's position than in the supine or crook lying position. The results of this study will help in the selection of the best alternative position for the spirometry in bed ridden patients.

  12. Fine-scale topography in sensory systems: insights from Drosophila and vertebrates.

    Science.gov (United States)

    Kaneko, Takuya; Ye, Bing

    2015-09-01

    To encode the positions of sensory stimuli, sensory circuits form topographic maps in the central nervous system through specific point-to-point connections between pre- and postsynaptic neurons. In vertebrate visual systems, the establishment of topographic maps involves the formation of a coarse topography followed by that of fine-scale topography that distinguishes the axon terminals of neighboring neurons. It is known that intrinsic differences in the form of broad gradients of guidance molecules instruct coarse topography while neuronal activity is required for fine-scale topography. On the other hand, studies in the Drosophila visual system have shown that intrinsic differences in cell adhesion among the axon terminals of neighboring neurons instruct the fine-scale topography. Recent studies on activity-dependent topography in the Drosophila somatosensory system have revealed a role of neuronal activity in creating molecular differences among sensory neurons for establishing fine-scale topography, implicating a conserved principle. Here we review the findings in both Drosophila and vertebrates and propose an integrated model for fine-scale topography.

  13. Reliability-based dynamic positioning of floating vessels with riser and mooring system

    DEFF Research Database (Denmark)

    Fang, Shaoji; Leira, Bernt J.; Blanke, Mogens

    2011-01-01

    To maintain safety of a floating vessel with associated slender components such as risers and mooring line, the vessel is normally kept within a limited region. To specify a safe position in that region, this paper suggests a new position chasing algorithm with the consideration of both riser ang...... to their criticality. An optimal position set-point is produced by minimization of the value of the cost function. Numerical simulations show the effectiveness of the proposed algorithm....

  14. High-precision drop shape analysis (HPDSA) of quasistatic contact angles on silanized silicon wafers with different surface topographies during inclining-plate measurements: Influence of the surface roughness on the contact line dynamics

    International Nuclear Information System (INIS)

    Heib, F.; Hempelmann, R.; Munief, W.M.; Ingebrandt, S.; Fug, F.; Possart, W.; Groß, K.; Schmitt, M.

    2015-01-01

    Highlights: • Analysis of the triple line motion on surfaces with nanoscale surface topographies. • Analysis of the triple line motion is performed in sub-pixel resolution. • A special fitting and statistical approach for contact angle analysis is applied. • The analyses result set of contact angle data which is independent of “user-skills”. • Characteristically density distributions in dependence on the surface properties. - Abstract: Contact angles and wetting of solid surfaces are strongly influenced by the physical and chemical properties of the surfaces. These influence quantities are difficult to distinguish from each other if contact angle measurements are performed by measuring only the advancing θ a and the receding θ r contact angle. In this regard, time-dependent water contact angles are measured on two hydrophobic modified silicon wafers with different physical surface topographies. The first surface is nearly atomically flat while the second surface is patterned (alternating flat and nanoscale rough patterns) which is synthesized by a photolithography and etching procedure. The different surface topographies are characterized with atomic force microscopy (AFM), Fourier transform infrared reflection absorption spectroscopy (FTIRRAS) and Fourier transform infrared attenuated total reflection spectroscopy (FTIR-ATR). The resulting set of contact angle data obtained by the high-precision drop shape analysis approach is further analyzed by a Gompertzian fitting procedure and a statistical counting procedure in dependence on the triple line velocity. The Gompertzian fit is used to analyze overall properties of the surface and dependencies between the motion on the front and the back edge of the droplets. The statistical counting procedure results in the calculation of expectation values E(p) and standard deviations σ(p) for the inclination angle φ, contact angle θ, triple line velocity vel and the covered distance of the triple line dis

  15. High-precision drop shape analysis (HPDSA) of quasistatic contact angles on silanized silicon wafers with different surface topographies during inclining-plate measurements: Influence of the surface roughness on the contact line dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Heib, F., E-mail: f.heib@mx.uni-saarland.de [Department of Physical Chemistry, Saarland University, 66123 Saarbrücken (Germany); Hempelmann, R. [Department of Physical Chemistry, Saarland University, 66123 Saarbrücken (Germany); Munief, W.M.; Ingebrandt, S. [Department of Informatics and Microsystem Technology, University of Applied Sciences, Kaiserslautern, 66482 Zweibrücken (Germany); Fug, F.; Possart, W. [Department of Adhesion and Interphases in Polymers, Saarland University, 66123 Saarbrücken (Germany); Groß, K.; Schmitt, M. [Department of Physical Chemistry, Saarland University, 66123 Saarbrücken (Germany)

    2015-07-01

    Highlights: • Analysis of the triple line motion on surfaces with nanoscale surface topographies. • Analysis of the triple line motion is performed in sub-pixel resolution. • A special fitting and statistical approach for contact angle analysis is applied. • The analyses result set of contact angle data which is independent of “user-skills”. • Characteristically density distributions in dependence on the surface properties. - Abstract: Contact angles and wetting of solid surfaces are strongly influenced by the physical and chemical properties of the surfaces. These influence quantities are difficult to distinguish from each other if contact angle measurements are performed by measuring only the advancing θ{sub a} and the receding θ{sub r} contact angle. In this regard, time-dependent water contact angles are measured on two hydrophobic modified silicon wafers with different physical surface topographies. The first surface is nearly atomically flat while the second surface is patterned (alternating flat and nanoscale rough patterns) which is synthesized by a photolithography and etching procedure. The different surface topographies are characterized with atomic force microscopy (AFM), Fourier transform infrared reflection absorption spectroscopy (FTIRRAS) and Fourier transform infrared attenuated total reflection spectroscopy (FTIR-ATR). The resulting set of contact angle data obtained by the high-precision drop shape analysis approach is further analyzed by a Gompertzian fitting procedure and a statistical counting procedure in dependence on the triple line velocity. The Gompertzian fit is used to analyze overall properties of the surface and dependencies between the motion on the front and the back edge of the droplets. The statistical counting procedure results in the calculation of expectation values E(p) and standard deviations σ(p) for the inclination angle φ, contact angle θ, triple line velocity vel and the covered distance of the triple

  16. Surface micro topography replication in injection moulding

    DEFF Research Database (Denmark)

    Arlø, Uffe Rolf

    Thermoplastic injection moulding is a widely used industrial process that involves surface generation by replication. The surface topography of injection moulded plastic parts can be important for aesthetical or technical reasons. With the emergence of microengineering and nanotechnology additional...... importance of surface topography follows. In general the replication is not perfect and the topography of the plastic part differs from the inverse topography of the mould cavity. It is desirable to be able to control the degree of replication perfection or replication quality. This requires an understanding...... of the physical mechanisms of replication. Such understanding can lead to improved process design and facilitate in-line process quality control with respect to surface properties. The purpose of the project is to identify critical factors that affect topography replication quality and to obtain an understanding...

  17. Modeling of human operator dynamics in simple manual control utilizing time series analysis. [tracking (position)

    Science.gov (United States)

    Agarwal, G. C.; Osafo-Charles, F.; Oneill, W. D.; Gottlieb, G. L.

    1982-01-01

    Time series analysis is applied to model human operator dynamics in pursuit and compensatory tracking modes. The normalized residual criterion is used as a one-step analytical tool to encompass the processes of identification, estimation, and diagnostic checking. A parameter constraining technique is introduced to develop more reliable models of human operator dynamics. The human operator is adequately modeled by a second order dynamic system both in pursuit and compensatory tracking modes. In comparing the data sampling rates, 100 msec between samples is adequate and is shown to provide better results than 200 msec sampling. The residual power spectrum and eigenvalue analysis show that the human operator is not a generator of periodic characteristics.

  18. In vivo dynamics of GFRα1-positive spermatogonia stimulated by GDNF signals using a bead transplantation assay

    Energy Technology Data Exchange (ETDEWEB)

    Uchida, Aya; Kishi, Kasane; Aiyama, Yoshimi; Miura, Kento [Department of Veterinary Anatomy, The University of Tokyo, Yayoi, Tokyo, 113-8657 (Japan); Takase, Hinako M.; Suzuki, Hitomi; Kanai-Azuma, Masami [Department of Experimental Animal Model for Human Disease, Tokyo Medical and Dental University, Tokyo, 113-8510 (Japan); Iwamori, Tokuko [Center of Biomedical Research, Kyusyu University, Fukuoka, 812-8582 (Japan); Kurohmaru, Masamichi; Tsunekawa, Naoki [Department of Veterinary Anatomy, The University of Tokyo, Yayoi, Tokyo, 113-8657 (Japan); Kanai, Yoshiakira, E-mail: aykanai@mail.ecc.u-tokyo.ac.jp [Department of Veterinary Anatomy, The University of Tokyo, Yayoi, Tokyo, 113-8657 (Japan)

    2016-08-05

    In mouse testes, spermatogonial stem cells (SSCs), a subpopulation of GFRα1 (GDNF family receptor-α1)-positive spermatogonia, are widely distributed along the convoluted seminiferous tubules. The proliferation and differentiation of the SSCs are regulated in part by local expression of GDNF (glial cell-derived neurotorphic factor), one of major niche factors for SSCs. However, the in vivo dynamics of the GDNF-stimulated GFRα1-positive spermatogonia remains unclear. Here, we developed a simple method for transplanting DiI-labeled and GDNF-soaked beads into the mouse testicular interstitium. By using this method, we examined the dynamics of GFRα1-positive spermatogonia in the tubular walls close to the transplanted GDNF-soaked beads. The bead-derived GDNF signals were able to induce the stratified aggregate formation of GFRα1-positive undifferentiated spermatogonia by day 3 post-transplantation. Each aggregate consisted of tightly compacted A{sub single} and marginal A{sub paired}–A{sub aligned} GFRα1-positive spermatogonia and was surrounded by A{sub aligned} GFRα1-negative spermatogonia at more advanced stages. These data not only provide in vivo evidence for the inductive roles of GDNF in forming a rapid aggregation of GFRα1-positive spermatogonia but also indicate the usefulness of this in vivo assay system of various growth factors for the stem/progenitor spermatogonia in mammalian spermatogenesis. - Highlights: • A novel bead transplantation assay was developed to examine the in vivo effects of growth factors on spermatogonia. • A rapid aggregation of GFRα1-positive spermatogonia was induced by the transplanted GDNF-soaked beads. • Tightly-compacted A{sub single} and marginal A{sub paired}–A{sub aligned} spermatogonia were formed in each GFRα1-positive aggregate.

  19. Dynamic Characteristics of Mechanical Ventilation System of Double Lungs with Bi-Level Positive Airway Pressure Model

    Directory of Open Access Journals (Sweden)

    Dongkai Shen

    2016-01-01

    Full Text Available In recent studies on the dynamic characteristics of ventilation system, it was considered that human had only one lung, and the coupling effect of double lungs on the air flow can not be illustrated, which has been in regard to be vital to life support of patients. In this article, to illustrate coupling effect of double lungs on flow dynamics of mechanical ventilation system, a mathematical model of a mechanical ventilation system, which consists of double lungs and a bi-level positive airway pressure (BIPAP controlled ventilator, was proposed. To verify the mathematical model, a prototype of BIPAP system with a double-lung simulators and a BIPAP ventilator was set up for experimental study. Lastly, the study on the influences of key parameters of BIPAP system on dynamic characteristics was carried out. The study can be referred to in the development of research on BIPAP ventilation treatment and real respiratory diagnostics.

  20. Critical Dynamics of the Xy-Model on the One-Dimensional Superlattice by Position Space Renormalization Group

    Science.gov (United States)

    Lima, J. P. De; Gonçalves, L. L.

    The critical dynamics of the isotropic XY-model on the one-dimensional superlattice is considered in the framework of the position space renormalization group theory. The decimation transformation is introduced by considering the equations of motion of the operators associated to the excitations of the system, and it corresponds to an extension of the procedure introduced by Stinchcombe and dos Santos (J. Phys. A18, L597 (1985)) for the homogeneous lattice. The dispersion relation is obtained exactly and the static and dynamic scaling forms are explicitly determined. The dynamic critical exponent is also obtained and it is shown that it is identical to the one of the XY-model on the homogeneous chain.

  1. Self-powered 'AND' logic circuit of dynamic type with positive safety and application of said 'AND' circuit

    International Nuclear Information System (INIS)

    Lefebvre, Claude; Therond, J.P.

    1974-01-01

    The present invention relates to a self-powered 'AND' logic circuit of dynamic type with positive safety, which delivers on duty operation an output signal equal to the logic product of the input logic signals. The invention relates also to the use of said 'AND' logic circuits in developing n/m logics also of dynamic types with positive safety, delivering on duty operation a zero valued signal when, at least n of the m input signals have the value zero. This type of logics can be inserted in nuclear reactor protection systems; when the value of the reactor operating physical characteristics go out of the safety margins, or true trouble affects 'AND' circuits the value of the output signal is zero, that triggers off the safety absorber drap, for instance [fr

  2. Strategy Dynamics through a Demand-Based Lens: The Evolution of Market Boundaries, Resource Rents and Competitive Positions

    OpenAIRE

    Adner, Ron; Zemsky, Peter

    2003-01-01

    We develop a novel approach to the dynamics of business strategy that is grounded in an explicit treatment of consumer choice when technologies improve over time. We address the evolution of market boundaries, resource rents and competitive positions by adapting models of competition with differentiated products. Our model is consistent with the central strategy assertion that competitive interactions are governed by superior value creation and competitive advantage. More importantly, it show...

  3. Continuous positive airway pressure alters cranial blood flow and cerebrospinal fluid dynamics at the craniovertebral junction

    Directory of Open Access Journals (Sweden)

    Theresia I. Yiallourou

    2015-09-01

    Conclusion: Application of CPAP via a full-fitted mask at 15 cm H2O was found to have a significant effect on intracranial venous outflow and spinal CSF flow at the C2 vertebral level in healthy adult-age awake volunteers. CPAP can be used to non-invasively provoke changes in intracranial and CSF flow dynamics.

  4. Reliability and reference values of two clinical measurements of dynamic and static knee position in healthy children

    DEFF Research Database (Denmark)

    Ortqvist, Maria; Moström, Eva B; Roos, Ewa M.

    2011-01-01

    PURPOSE: The purposes of this study were to evaluate reliability of the Single-limb mini squat test (a dynamic measure of medio-lateral knee position) and the Quadriceps-angle (Q-angle) (a static measure of medio-lateral knee position), present paediatric reference values of the Q......-angle measurements was found. Reference values for the Q-angle (mean 13.5° (1.9)-15.3° (2.8)) varies with age and gender. No associations were found between dynamic and static measures. CONCLUSIONS: The Single-limb mini squat test showed a moderate reliability and the Q-angle showed a fair to moderate reliability......-angle, and evaluate the association between the tests. METHODS: Two hundred and forty-six healthy children (9-16 years) were included (intra/inter-rater reliability for Q-angle (n = 37/85) and for Single-limb mini squat test (n = 33/28)). Dynamic medio-lateral knee position was assessed by the Single-limb mini squat...

  5. Leading-process actomyosin coordinates organelle positioning and adhesion receptor dynamics in radially migrating cerebellar granule neurons.

    Science.gov (United States)

    Trivedi, Niraj; Ramahi, Joseph S; Karakaya, Mahmut; Howell, Danielle; Kerekes, Ryan A; Solecki, David J

    2014-12-02

    During brain development, neurons migrate from germinal zones to their final positions to assemble neural circuits. A unique saltatory cadence involving cyclical organelle movement (e.g., centrosome motility) and leading-process actomyosin enrichment prior to nucleokinesis organizes neuronal migration. While functional evidence suggests that leading-process actomyosin is essential for centrosome motility, the role of the actin-enriched leading process in globally organizing organelle transport or traction forces remains unexplored. We show that myosin ii motors and F-actin dynamics are required for Golgi apparatus positioning before nucleokinesis in cerebellar granule neurons (CGNs) migrating along glial fibers. Moreover, we show that primary cilia are motile organelles, localized to the leading-process F-actin-rich domain and immobilized by pharmacological inhibition of myosin ii and F-actin dynamics. Finally, leading process adhesion dynamics are dependent on myosin ii and F-actin. We propose that actomyosin coordinates the overall polarity of migrating CGNs by controlling asymmetric organelle positioning and cell-cell contacts as these cells move along their glial guides.

  6. Can positional MRI predict dynamic changes in the medial plantar arch?

    DEFF Research Database (Denmark)

    Johannsen, Finn E; Hansen, Philip; Stallknecht, Sandra

    2016-01-01

    BACKGROUND: Positional MRI (pMRI) allows for three-dimensional visual assessment of navicular position. In this exploratory pilot study pMRI was validated against a stretch sensor device, which measures movement of the medial plantar arch. We hypothesized that a combined pMRI measure incorporating...... and c) standing position with addition of 10 % body weight during static loading of the foot. Stretch sensor measurements were also performed during barefoot walking. RESULTS: The total change in navicular position measured by pMRI was 10.3 mm (CI: 7.0 to 13.5 mm). No further displacement occurred when.......08). CONCLUSIONS: Total navicular bone displacements determined by pMRI showed concurrent validity with stretch sensor measurements but only so under static loading conditions. Although assessment of total navicular displacement by combining concomitant vertical and medial navicular bone movements would appear...

  7. Microprocessor-controlled time domain reflectometer for dynamic shock position measurements

    International Nuclear Information System (INIS)

    Virchow, C.F.; Conrad, G.E.; Holt, D.M.; Hodson, E.K.

    1980-01-01

    Time-domain reflectometry is used in a novel way to measure dynamically shock propagation in various media. The primary component in this measurement system is a digital time domain reflectometer, which uses local intelligence, a Motorola 6800 microprocessor, to make the unit adaptable and versatile. The recorder, its operating theory and its method of implementation are described and typical data are reviewed. Applications include nuclear explosion yield estimates and explosive energy flow measurements

  8. About a Class of Positive Hybrid Dynamic Linear Systems and an Associate Extended Kalman-Yakubovich-Popov Lemma

    Directory of Open Access Journals (Sweden)

    M. De la Sen

    2017-01-01

    Full Text Available This paper formulates an “ad hoc” robust version under parametrical disturbances of the discrete version of the Kalman-Yakubovich-Popov Lemma for a class of positive hybrid dynamic linear systems which consist of a continuous-time system coupled with a discrete-time or a digital one. An extended discrete system, whose state vector contains both the digital one and the discretization of the continuous-time one at sampling instants, is a key analysis element in the formulation. The hyperstability and asymptotic hyperstability properties of the studied class of positive hybrid systems under feedback from any member of a nonlinear (and, eventually, time-varying class of controllers, which satisfies a Popov’s-type inequality, are also investigated as linked to the positive realness of the associated transfer matrices.

  9. Patient positioning and immobilization in static and dynamic adaptive radiotherapy: an integral part of IGRT

    International Nuclear Information System (INIS)

    Oinam, Arun S.

    2016-01-01

    Radiotherapy treatment deals with different varieties of treatment procedures depending on type and stages of tumors. These treatments are grossly classified into palliative curative treatment. Immobilizations used in this treatment are designed with respect to this classification as well as the techniques. With the improvements in imaging technology used in Radiotherapy, patient position set up margin can be reduced as compared to the conventional radiotherapy. Still immobilization in patient position setup has been an integral part of Image Guided Radiotherapy (lGRT) and Stereotactic Radio Surgery (SRS) and Radiotherapy (SRT). Immobilization used in this technique should produce a minimum attenuation of radiation beam as well as positioning comfort and this will enhance the reproducibility for the daily position setup and immobilize the patient during the treatment. Advanced dose delivery technique like Intensity Modulated Radiotherapy (IMRT) and Volumetric Modulated Arc Radiotherapy (VMAT) can do differential dose sculpting around and inside the irregular shape different target volumes while minimizing the dose to the surrounding organs at risk. A small positional error may produce the mistreatment of target and exposure of organs at risk beyond the acceptable dose limits. Such a potential positional error can be reduced if different varieties of good immobilizing devices are properly utilized. The immobilization used in the treatment of Head and Neck and Cranial tumor can produce better immobilization as compared to abdominal and pelvic tumors which are forced to move by the inability to control movements of lung and heart as well as the very large flabby tissues which are attached skeleton bones

  10. Systematic comparison of position and time dependent macroparticle simulations in beam dynamics studies

    Directory of Open Access Journals (Sweden)

    Ji Qiang

    2002-06-01

    Full Text Available Macroparticle simulation plays an important role in modern accelerator design and operation. Most linear rf accelerators have been designed based on macroparticle simulations using longitudinal position as the independent variable. In this paper, we have done a systematic comparison between using longitudinal position as the independent variable and using time as the independent variable in macroparticle simulations. We have found that, for an rms-matched beam, the maximum relative moment difference for second, fourth moments and beam maximum amplitudes between these two types of simulations is 0.25% in a 10 m reference transport system with physical parameters similar to the Spallation Neutron Source linac design. The maximum z-to- t transform error in the space-charge force calculation of the position dependent simulation is about 0.1% in such a system. This might cause a several percent error in a complete simulation of a linac with a length of hundreds of meters. Furthermore, the error may be several times larger in simulations of mismatched beams. However, if such errors are acceptable to the linac designer, then one is justified in using position dependent macroparticle simulations in this type of linac design application.

  11. The Dynamics of Finite-Dimensional Systems Under Nonconservative Position Forces

    Science.gov (United States)

    Lobas, L. G.

    2001-01-01

    General theorems on the stability of stationary states of mechanical systems subjected to nonconservative position forces are presented. Specific mechanical problems on gyroscopic systems, a double-link pendulum with a follower force and elastically fixed upper tip, multilink pneumowheel vehicles, a monorail car, and rail-guided vehicles are analyzed. Methods for investigation of divergent bifurcations and catastrophes of stationary states are described

  12. Framing Negotiation: Dynamics of Epistemological and Positional Framing in Small Groups during Scientific Modeling

    Science.gov (United States)

    Shim, Soo-Yean; Kim, Heui-Baik

    2018-01-01

    In this study, we examined students' epistemological and positional framing during small group scientific modeling to explore their context-dependent perceptions about knowledge, themselves, and others. We focused on two small groups of Korean eighth-grade students who participated in six modeling activities about excretion. The two groups were…

  13. English Learners' Participation in Mathematical Discussion: Shifting Positionings and Dynamic Identities

    Science.gov (United States)

    Turner, Erin; Dominguez, Higinio; Maldonado, Luz; Empson, Susan

    2013-01-01

    This study investigated discursive positioning moves that facilitated Latino/a English learners' (ELs) opportunities to take on agentive problem-solving roles in group mathematical discussion. A focus on mechanisms that support students' agentive participation is consistent with the authors' view that recurrent experiences participating and being…

  14. A dynamic programming algorithm for the space allocation and aisle positioning problem

    DEFF Research Database (Denmark)

    Bodnar, Peter; Lysgaard, Jens

    2014-01-01

    The space allocation and aisle positioning problem (SAAPP) in a material handling system with gravity flow racks is the problem of minimizing the total number of replenishments over a period subject to practical constraints related to the need for aisles granting safe and easy access to storage...

  15. Resilience in Change: Positive Perspectives on the Dynamics of Change in Early Childhood Systems

    Science.gov (United States)

    Douglass, Anne

    2016-01-01

    Change is a central feature of the early care and education landscape today. Much of the research on educational change focuses on the negative or challenging aspects of change. This study employed a critical theory framework from the organizational sciences field, positive organizational scholarship, to offer a new way of thinking about change in…

  16. The Global Positioning System (GPS) and attitude determination: Applications and activities in the Flight Dynamics Division

    Science.gov (United States)

    Ketchum, Eleanor; Garrick, Joe

    1995-01-01

    The application of GPS to spacecraft attitude determination is a new and growing field. Although the theoretical literature is extensive, space flight testing is currently sparse and inadequate. As an operations organization, the Flight Dynamics Division (FDD) has the responsibility to investigate this new technology, and determine how best to implement the innovation to provide adequate support for future missions. This paper presents some of the current efforts within FDD with regard to GPS attitude determination. This effort specifically addresses institutional capabilities to accommodate a new type of sensor, critically evaluating the literature for recent advancements, and in examining some available -albeit crude- flight data.

  17. Mapping Bedrock Topography using Electromagnetic Profiling ...

    African Journals Online (AJOL)

    Mapping Bedrock Topography using Electromagnetic Profiling. ... will be constructed The area under study is within the Abakaliki Shales Geologic Formation. ... micaceous sandstone; micaceous siltstone, sandy shales and shelly limestone.

  18. Dynamic characteristics of positive hollow needle to plate atmospheric pressure discharge

    Czech Academy of Sciences Publication Activity Database

    Khun, J.; Šimek, Milan; Pekárek, S.; Schmidt, Jiří

    2006-01-01

    Roč. 56, suppl.B (2006), s. 830-836 ISSN 0011-4626. [Symposium on Plasma Physics and Technology/22nd./. Praha, 26.6.2006-29.6.2006] R&D Projects: GA AV ČR(CZ) IAA1043403 Institutional research plan: CEZ:AV0Z20430508 Keywords : positive corona discharge * streamer * mean repetition frequency * mean propagation velocity Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 0.568, year: 2006

  19. Temporal dynamics of ocular position dependence of the initial human vestibulo-ocular reflex.

    Science.gov (United States)

    Crane, Benjamin T; Tian, Junru; Demer, Joseph L

    2006-04-01

    While an ideal vestibulo-ocular reflex (VOR) generates ocular rotations compensatory for head motion, during visually guided movements, Listing's Law (LL) constrains the eye to rotational axes lying in Listing's Plane (LP). The present study was conducted to explore the recent proposal that the VOR's rotational axis is not collinear with the head's, but rather follows a time-dependent strategy intermediate between LL and an ideal VOR. Binocular LPs were defined during visual fixation in eight normal humans. The VOR was evoked by a highly repeatable transient whole-body yaw rotation in darkness at a peak acceleration of 2800 deg/s2. Immediately before rotation, subjects regarded targets 15 or 500 cm distant located at eye level, 20 degrees up, or 20 degrees down. Eye and head responses were compared with LL predictions in the position and velocity domains. LP orientation varied both among subjects and between individual subject's eyes, and rotated temporally with convergence by 5 +/- 5 degrees (+/-SEM). In the position domain, the eye compensated for head displacement even when the head rotated out of LP. Even within the first 20 ms from onset of head rotation, the ocular velocity axis tilted relative to the head axis by 30% +/- 8% of vertical gaze position. Saccades increased this tilt. Regardless of vertical gaze position, the ocular rotation axis tilted backward 4 degrees farther in abduction than in adduction. There was also a binocular vertical eye velocity transient and lateral tilt of the ocular axis. These disconjugate, short-latency axis perturbations appear intrinsic to the VOR and may have neural or mechanical origins.

  20. Use of dynamic CT in acute respiratory distress syndrome (ARDS) with comparison of positive and negative pressure ventilation

    Energy Technology Data Exchange (ETDEWEB)

    Helm, Emma; Babyn, Paul [Hospital for Sick Children, Department of Diagnostic Imaging, Toronto (Canada); Talakoub, Omid; Alirezaie, Javad [Ryerson University, Department of Electrical and Computer Engineering, Toronto, ON (Canada); Grasso, Francesco; Engelberts, Doreen; Kavanagh, Brian P. [Hospital for Sick Children and the University of Toronto, Departments of Anesthesia and Critical Care Medicine and the Program in Pulmonary and Experimental Medicine, Toronto (Canada)

    2009-01-15

    Negative pressure ventilation via an external device ('iron lung') has the potential to provide better oxygenation with reduced barotrauma in patients with ARDS. This study was designed to see if oxygenation differences between positive and negative ventilation could be explained by CT. Six anaesthetized rabbits had ARDS induced by repeated saline lavage. Rabbits were ventilated with positive pressure ventilation (PPV) and negative pressure ventilation (NPV) in turn. Dynamic CT images were acquired over the respiratory cycle. A computer-aided method was used to segment the lung and calculate the range of CT densities within each slice. Volumes of ventilated lung and atelectatic lung were measured over the respiratory cycle. NPV was associated with an increased percentage of ventilated lung and decreased percentage of atelectatic lung. The most significant differences in ventilation and atelectasis were seen at mid-inspiration and mid-expiration (ventilated lung NPV=61%, ventilated lung PPV=47%, p<0.001; atelectatic lung NPV=10%, atelectatic lung PPV 19%, p<0.001). Aeration differences were not significant at end-inspiration. Dynamic CT can show differences in lung aeration between positive and negative ventilation in ARDS. These differences would not be appreciated if only static breath-hold CT was used. (orig.)

  1. Estimation of position and velocity for a low dynamic vehicle in near space using nonresolved photometric and astrometric data.

    Science.gov (United States)

    Jing, Nan; Li, Chuang; Chong, Yaqin

    2017-01-20

    An estimation method for indirectly observable parameters for a typical low dynamic vehicle (LDV) is presented. The estimation method utilizes apparent magnitude, azimuth angle, and elevation angle to estimate the position and velocity of a typical LDV, such as a high altitude balloon (HAB). In order to validate the accuracy of the estimated parameters gained from an unscented Kalman filter, two sets of experiments are carried out to obtain the nonresolved photometric and astrometric data. In the experiments, a HAB launch is planned; models of the HAB dynamics and kinematics and observation models are built to use as time update and measurement update functions, respectively. When the HAB is launched, a ground-based optoelectronic detector is used to capture the object images, which are processed using aperture photometry technology to obtain the time-varying apparent magnitude of the HAB. Two sets of actual and estimated parameters are given to clearly indicate the parameter differences. Two sets of errors between the actual and estimated parameters are also given to show how the estimated position and velocity differ with respect to the observation time. The similar distribution curve results from the two scenarios, which agree within 3σ, verify that nonresolved photometric and astrometric data can be used to estimate the indirectly observable state parameters (position and velocity) for a typical LDV. This technique can be applied to small and dim space objects in the future.

  2. Nonlinear Dynamic Analysis on the Rain-Wind-Induced Vibration of Cable Considering the Equilibrium Position of Rivulet

    Directory of Open Access Journals (Sweden)

    Xijun Liu

    2013-01-01

    Full Text Available The nonlinear dynamic behavior of rain-wind-induced vibration of inclined cable is investigated with the consideration of the equilibrium position of the moving rivulet. The partial differential governing equations of three-degree-of-freedom on the model of rain-wind-induced cable vibration are established, which are proposed for describing the nonlinear interactions among the in-plane, out-of-plane vibration of the cable and the oscillation of the moving rivulet. The Galerkin method is applied to discretize the partial differential governing equations. The approximately analytic solution is obtained by using the method of averaging. The unique correspondence between the wind and the equilibrium position of the rivulet is ascertained. The presence of rivulet at certain positions on the surface of cable is then proved to be one of the trigger for wind-rain-induced cable vibration. The nonlinear dynamic phenomena of the inclined cable subjected to wind and rain turbulence are then studied by varying the parameters including mean wind velocity, Coulomb damping force, damping ratio, the span length, and the initial tension of the inclined cable on the model. The jump phenomenon is also observed which occurs when there are multiple solutions in the system.

  3. On effects of topography in rotating flows

    Science.gov (United States)

    Burmann, Fabian; Noir, Jerome; Jackson, Andrew

    2017-11-01

    Both, seismological studies and geodynamic arguments suggest that there is significant topography at the core mantle boundary (CMB). This leads to the question whether the topography of the CMB could influence the flow in the Earth's outer core. As a preliminary experiment, we investigate the effects of bottom topography in the so-called Spin-Up, where motion of a contained fluid is created by a sudden increase of rotation rate. Experiments are performed in a cylindrical container mounted on a rotating table and quantitative results are obtained with particle image velocimetry. Several horizontal length scales of topography (λ) are investigated, ranging from cases where λ is much smaller then the lateral extend of the experiment (R) to cases where λ is a fraction of R. We find that there is an optimal λ that creates maximum dissipation of kinetic energy. Depending on the length scale of the topography, kinetic energy is either dissipated in the boundary layer or in the bulk of the fluid. Two different phases of fluid motion are present: a starting flow in the from of solid rotation (phase I), which is later replaced by meso scale vortices on the length scale of bottom topography (phase II).

  4. Surface Topography Hinders Bacterial Surface Motility.

    Science.gov (United States)

    Chang, Yow-Ren; Weeks, Eric R; Ducker, William A

    2018-03-21

    We demonstrate that the surface motility of the bacterium, Pseudomonas aeruginosa, is hindered by a crystalline hemispherical topography with wavelength in the range of 2-8 μm. The motility was determined by the analysis of time-lapse microscopy images of cells in a flowing growth medium maintained at 37 °C. The net displacement of bacteria over 5 min is much lower on surfaces containing 2-8 μm hemispheres than on flat topography, but displacement on the 1 μm hemispheres is not lower. That is, there is a threshold between 1 and 2 μm for response to the topography. Cells on the 4 μm hemispheres were more likely to travel parallel to the local crystal axis than in other directions. Cells on the 8 μm topography were less likely to travel across the crowns of the hemispheres and were also more likely to make 30°-50° turns than on flat surfaces. These results show that surface topography can act as a significant barrier to surface motility and may therefore hinder surface exploration by bacteria. Because surface exploration can be a part of the process whereby bacteria form colonies and seek nutrients, these results help to elucidate the mechanism by which surface topography hinders biofilm formation.

  5. Measuring topographies from conventional SEM acquisitions.

    Science.gov (United States)

    Shi, Qiwei; Roux, Stéphane; Latourte, Félix; Hild, François; Loisnard, Dominique; Brynaert, Nicolas

    2018-04-27

    The present study extends the stereoscopic imaging principle for estimating the surface topography to two orientations, namely, normal to the electron beam axis and inclined at 70° as suited for EBSD analyses. In spite of the large angle difference, it is shown that the topography can be accurately determined using regularized global Digital Image Correlation. The surface topography is compared to another estimate issued from a 3D FIB-SEM procedure where the sample surface is first covered by a Pt layer, and its initial topography is progressively revealed from successive FIB-milling. These two methods are successfully compared on a 6% strained steel specimen in an in situ mechanical test. This analysis is supplemented by a third approach estimating the change of topography from crystal rotations as measured from successive EBSD images. This last technique ignores plastic deformation, and thus only holds in an elastic regime. For the studied example, despite the large plastic flow, it is shown that crystal rotation already accounts for a significant part of the deformation-induced topography. Copyright © 2018 Elsevier B.V. All rights reserved.

  6. Corneal topography measurements for biometric applications

    Science.gov (United States)

    Lewis, Nathan D.

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

  7. Structural analysis of eyespots: dynamics of morphogenic signals that govern elemental positions in butterfly wings

    Directory of Open Access Journals (Sweden)

    Otaki Joji M

    2012-03-01

    Full Text Available Abstract Background To explain eyespot colour-pattern determination in butterfly wings, the induction model has been discussed based on colour-pattern analyses of various butterfly eyespots. However, a detailed structural analysis of eyespots that can serve as a foundation for future studies is still lacking. In this study, fundamental structural rules related to butterfly eyespots are proposed, and the induction model is elaborated in terms of the possible dynamics of morphogenic signals involved in the development of eyespots and parafocal elements (PFEs based on colour-pattern analysis of the nymphalid butterfly Junonia almana. Results In a well-developed eyespot, the inner black core ring is much wider than the outer black ring; this is termed the inside-wide rule. It appears that signals are wider near the focus of the eyespot and become narrower as they expand. Although fundamental signal dynamics are likely to be based on a reaction-diffusion mechanism, they were described well mathematically as a type of simple uniformly decelerated motion in which signals associated with the outer and inner black rings of eyespots and PFEs are released at different time points, durations, intervals, and initial velocities into a two-dimensional field of fundamentally uniform or graded resistance; this produces eyespots and PFEs that are diverse in size and structure. The inside-wide rule, eyespot distortion, structural differences between small and large eyespots, and structural changes in eyespots and PFEs in response to physiological treatments were explained well using mathematical simulations. Natural colour patterns and previous experimental findings that are not easily explained by the conventional gradient model were also explained reasonably well by the formal mathematical simulations performed in this study. Conclusions In a mode free from speculative molecular interactions, the present study clarifies fundamental structural rules related to

  8. Structural analysis of eyespots: dynamics of morphogenic signals that govern elemental positions in butterfly wings.

    Science.gov (United States)

    Otaki, Joji M

    2012-03-13

    To explain eyespot colour-pattern determination in butterfly wings, the induction model has been discussed based on colour-pattern analyses of various butterfly eyespots. However, a detailed structural analysis of eyespots that can serve as a foundation for future studies is still lacking. In this study, fundamental structural rules related to butterfly eyespots are proposed, and the induction model is elaborated in terms of the possible dynamics of morphogenic signals involved in the development of eyespots and parafocal elements (PFEs) based on colour-pattern analysis of the nymphalid butterfly Junonia almana. In a well-developed eyespot, the inner black core ring is much wider than the outer black ring; this is termed the inside-wide rule. It appears that signals are wider near the focus of the eyespot and become narrower as they expand. Although fundamental signal dynamics are likely to be based on a reaction-diffusion mechanism, they were described well mathematically as a type of simple uniformly decelerated motion in which signals associated with the outer and inner black rings of eyespots and PFEs are released at different time points, durations, intervals, and initial velocities into a two-dimensional field of fundamentally uniform or graded resistance; this produces eyespots and PFEs that are diverse in size and structure. The inside-wide rule, eyespot distortion, structural differences between small and large eyespots, and structural changes in eyespots and PFEs in response to physiological treatments were explained well using mathematical simulations. Natural colour patterns and previous experimental findings that are not easily explained by the conventional gradient model were also explained reasonably well by the formal mathematical simulations performed in this study. In a mode free from speculative molecular interactions, the present study clarifies fundamental structural rules related to butterfly eyespots, delineates a theoretical basis for the

  9. The Dynamics of Quadropoly: League Position in English Football between 1888 and 2010

    OpenAIRE

    Penn, Roger; Berridge, Damon

    2016-01-01

    The paper explores competitive balance in top tier English league football from its inception in 1888. It examines the extent to which finishing in the top four positions in successive seasons is the preserve of a small number of clubs. Using a range of statistical measures, the analysis shows that the current high levels of competitive imbalance are not new phenomena. The overall pattern approximates a ‘U curve’: current patterns parallel those in the 1890s. In the early years of English lea...

  10. Virtual reality simulation of fuzzy-logic control during underwater dynamic positioning

    Science.gov (United States)

    Thekkedan, Midhin Das; Chin, Cheng Siong; Woo, Wai Lok

    2015-03-01

    In this paper, graphical-user-interface (GUI) software for simulation and fuzzy-logic control of a remotely operated vehicle (ROV) using MATLAB™ GUI Designing Environment is proposed. The proposed ROV's GUI platform allows the controller such as fuzzy-logic control systems design to be compared with other controllers such as proportional-integral-derivative (PID) and sliding-mode controller (SMC) systematically and interactively. External disturbance such as sea current can be added to improve the modelling in actual underwater environment. The simulated results showed the position responses of the fuzzy-logic control exhibit reasonable performance under the sea current disturbance.

  11. Simulation of personalised haemodynamics by various mounting positions of a prosthetic valve using computational fluid dynamics.

    Science.gov (United States)

    Bongert, Markus; Geller, Marius; Pennekamp, Werner; Nicolas, Volkmar

    2018-03-03

    Diseases of the cardiovascular system account for nearly 42% of all deaths in the European Union. In Germany, approximately 12,000 patients receive surgical replacement of the aortic valve due to heart valve disease alone each year. A three-dimensional (3D) numerical model based on patient-specific anatomy derived from four-dimensional (4D) magnetic resonance imaging (MRI) data was developed to investigate preoperatively the flow-induced impact of mounting positions of aortic prosthetic valves to select the best orientation for individual patients. Systematic steady-state analysis of blood flow for different rotational mounting positions of the valve is only possible using a virtual patient model. A maximum velocity of 1 m/s was used as an inlet boundary condition, because the opening angle of the valve is at its largest at this velocity. For a comparative serial examination, it is important to define the standardised general requirements to avoid impacts other than the rotated implantation of the prosthetic aortic valve. In this study, a uniform velocity profile at the inlet for the inflow of the aortic valve and the real aortic anatomy were chosen for all simulations. An iterative process, with the weighted parameters flow resistance (1), shear stress (2) and velocity (3), was necessary to determine the best rotated orientation. Blood flow was optimal at a 45° rotation from the standard implantation orientation, which will offer a supply to the coronary arteries.

  12. School scoliosis screening by Moiré topography - Overview for 33 years in Miyazaki Japan.

    Science.gov (United States)

    Kuroki, Hiroshi; Nagai, Takuya; Chosa, Etsuo; Tajima, Naoya

    2018-04-05

    Since 1981, we have performed school scoliosis screening (SSS) using Moiré topography in Miyazaki, Japan and attained a certain result in detecting scoliosis. However, this screening system was discontinued due to cessation of repair and production of Moiré topographic equipment. The purpose of this study was to make clear both the results and the problems of SSS by Moiré topography on the basis of our past 33 years' experiences. The subjects were 689,293 students (5th grade boys in 200,329, 5th grade girls in 191,919, 8th grade boys in 151,351, and 8th grade girls in 145,694) who were screened by Moiré topography between 1981 and 2013. The number of students received SSS, the positive rate of Moiré topography, the discovery rate of scoliosis greater than 20°, the reference rate to the second screening, and the positive predictive value of Moiré topography to detect scoliosis greater than 20° were investigated. The number of students received SSS achieved a peak in 1992. The positive rate of Moiré topography and the discovery rate of scoliosis were highest in 8th grade girls. The reference rates to the second screening were 49.8% in 5th grade students and 41.4% in 8th grade students. The positive predictive values were 2.1% in 5th grade students and 7.6% in 8th grade students. SSS by Moiré topography seemed to be effective in detecting scoliosis although both the positive predictive value and the reference rate to the second screening were low. Copyright © 2018. Published by Elsevier B.V.

  13. Gravity, Topography, and Magnetic Field of Mercury from Messenger

    Science.gov (United States)

    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.; hide

    2012-01-01

    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 dynamic 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 topography 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

  14. ATM Coastal Topography-Texas, 2001: UTM Zone 14

    Science.gov (United States)

    Klipp, Emily S.; Nayegandhi, Amar; Brock, John C.; Sallenger, A.H.; Bonisteel, Jamie M.; Yates, Xan; Wright, C. Wayne

    2009-01-01

    These remotely sensed, geographically referenced elevation measurements of lidar-derived first-surface (FS) topography 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 a portion of the Texas coastline within UTM zone 14, acquired October 12-13, 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 topography 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 topography 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 is used

  15. ATM Coastal Topography-Florida 2001: Eastern Panhandle

    Science.gov (United States)

    Yates, Xan; Nayegandhi, Amar; Brock, John C.; Sallenger, A.H.; Bonisteel, Jamie M.; Klipp, Emily S.; Wright, C. Wayne

    2009-01-01

    These remotely sensed, geographically referenced elevation measurements of Lidar-derived first surface (FS) topography 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 eastern Florida panhandle coastline, acquired October 2, 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 topography 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 topography 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 is routinely used to create

  16. ATM Coastal Topography-Texas, 2001: UTM Zone 15

    Science.gov (United States)

    Klipp, Emily S.; Nayegandhi, Amar; Brock, John C.; Sallenger, A.H.; Bonisteel, Jamie M.; Yates, Xan; Wright, C. Wayne

    2009-01-01

    These remotely sensed, geographically referenced elevation measurements of lidar-derived first-surface (FS) topography 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 a portion of the Texas coastline within UTM zone 15, from Matagorda Peninsula to Galveston Island, acquired October 12-13, 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 topography 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 topography 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

  17. ATM Coastal Topography-Florida 2001: Western Panhandle

    Science.gov (United States)

    Yates, Xan; Nayegandhi, Amar; Brock, John C.; Sallenger, A.H.; Bonisteel, Jamie M.; Klipp, Emily S.; Wright, C. Wayne

    2009-01-01

    These remotely sensed, geographically referenced elevation measurements of Lidar-derived first surface (FS) topography 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 western Florida panhandle coastline, acquired October 2-4 and 7-10, 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 topography 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 topography 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 is routinely used

  18. Dynamic Contraction of the Positive Column of a Self-Sustained Glow Discharge in Molecular Gas Flow

    Science.gov (United States)

    Shneider, Mikhail

    2014-10-01

    Contraction of the gas discharge, when current contracts from a significant volume of weakly ionized plasma into a thin arc channel, was attracted attention of scientists for more than a century. Studies of the contraction (also called constriction) mechanisms, besides carrying interesting science, are of practical importance, especially when contraction should be prevented. A set of time-dependent two-dimensional equations for the non-equilibrium weakly-ionized nitrogen/ air plasma is formulated. The process is described by a set of time-dependent continuity equations for the electrons, positive and negative ions; gas and vibrational temperature; by taking into account the convective heat and plasma losses by the transverse flux. Transition from the uniform to contracted state was analyzed. It was shown that such transition experiences a hysteresis, and that the critical current of the transition increases when the pressure (gas density) drops. Possible coexistence of the contracted and uniform state of the plasma in the discharge where the current flows along the density gradient of the background gas was discussed. In this talk the problems related to the dynamic contraction of the current channel inside a quasineutral positive column of a self-sustained glow discharge in molecular gas in a rectangular duct with convection cooling will be discussed. Study presented in this talk was stimulated by the fact that there are large number of experiments on the dynamic contraction of a glow discharge in nitrogen and air flows and a many of possible applications. Similar processes play a role in the powerful gas-discharge lasers. In addition, the problem of dynamic contraction in the large volume of non-equilibrium weakly ionized plasma is closely related to the problem of streamer to leader transitions in lightning and blue jets.

  19. Electronic Cigarette Topography in the Natural Environment.

    Science.gov (United States)

    Robinson, R J; Hensel, E C; Morabito, P N; Roundtree, K A

    2015-01-01

    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 topography 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 topography 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 topography 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 topography, suggesting that a range of representative puffing topography patterns should be used to drive machine-puffed electronic cigarette aerosol evaluation systems.

  20. Epithelial topography for repetitive tooth formation

    Directory of Open Access Journals (Sweden)

    Marcia Gaete

    2015-12-01

    Full Text Available 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 topography 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.

  1. Self-treatment of benign paroxysmal positional vertigo with DizzyFix, a new dynamic visual device.

    Science.gov (United States)

    Brehmer, Detlef

    2010-09-01

    Benign paroxysmal positional vertigo is one of the most common disorders of the vestibular system. It is characterized by episodes of recurrent vertigo triggered by head movements or position changes associated with nystagmus. There is scientific evidence that in the majority of cases this condition responds well to the particle repositioning maneuver (PRM) correctly performed by the physician. However, the PRM needs to be repeated in approximately 30% of the cases. Although the maneuver is simple, patients often find it difficult to perform correctly as self-treatment, with the result that it fails to bring about an improvement in the symptoms. DizzyFix (Clearwater Clinical Limited, Canada) is the name given to a new dynamic visual device designed to provide a visual representation of the PRM based on the canalith theory. The DizzyFiX consists of a specially curved acrylic tube containing a nontoxic viscous fluid and a bead, the purpose of which is to help the patient and the inexperienced physician to perform the PRM correctly. A randomized clinical trial has shown that it reliably enables the maneuver to be performed correctly, and a study investigating the effectiveness of patient self-treatment of benign paroxysmal positional vertigo with the device in comparison with standard office treatment revealed both techniques to be equally effective. The device has now been approved by the US FDA.

  2. High-speed X-ray topography

    International Nuclear Information System (INIS)

    Eckers, W.; Oppolzer, H.

    1977-01-01

    The investigation of lattice defects in semiconductor crystals by conventional X-ray diffraction topography is very time-consuming. Exposure times can be reduced by using high-intensity X-rays and X-ray image intensifiers. The described system comprises a high-power rotating-anode X-ray tube, a remote-controlled X-ray topography camera, and a television system operating with an X-ray sensing VIDICON. System performance is demonstrated with reference to exploratory examples. The exposure time for photographic plates is reduced to 1/20 and for the X-ray TV system (resolution of the order of 30 μm) to 1/100 relative to that required when using a conventional topography system. (orig.) [de

  3. Experiments on topographies lacking tidal conversion

    Science.gov (United States)

    Maas, Leo; Paci, Alexandre; Yuan, Bing

    2015-11-01

    In a stratified sea, internal tides are supposedly generated when the tide passes over irregular topography. 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 topography 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 topography, 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.

  4. Australian plate motion and topography linked to fossil New Guinea slab below Lake Eyre

    NARCIS (Netherlands)

    Schellart, W. P.; Spakman, W.

    2015-01-01

    Unravelling causes for absolute plate velocity change and continental dynamic topography 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

  5. The application in detection the position accuracy of the multi-leaf collimator of Varian linear accelerator with dynamic therapy log files

    International Nuclear Information System (INIS)

    Li Changhu; Xu Liming; Teng Jianjian; Ge Wei; Zhang Jun; Ma Guangdong

    2010-01-01

    Objective: To explorer the application in detection the position accuracy of the multileaf collimator of Varian accelerator with dynamic therapy log files. Methods: A pre-designed MLC format files named PMLC for two Varian accelerators, the dynamic treatment log files were recorded 10 times on a different date, and be converted into the MLC format files named DMLC, compared with the original plan PMLC, so we can analysis two files for each leaf position deviation. In addition, we analysis the repeatability of MLC leaves position accuracy between 10 dynalog files of two accelerators. Results: No statistically significant difference between the average position of the 10 times leaf position of the two accelerators,their were 0.29 -0.29 and 0.29 -0.30 (z = -0.77, P=0.442). About 40%, 30%, 20% and 10% of the leaf position deviation was at ≤0.2 mm, 0.3 mm, 0.5 mm and 0.4 mm, respectively. the maximum value was 0.5 mm. More than 86% of the leaf position are completely coincident between 10 dynamic treatment files of two accelerators. The rate of position deviation no more 0. 05 mm was 96. 6% and 97.3%, respectively. And the maximum value was 0.09 mm. Conclusions: Dynamic treatment log file is a splendid tool in testing the actual position of multi-leaf collimator. The multi-leaf collimator of two accelerators be detected are precise and stabilized. (authors)

  6. Open questions in surface topography measurement: a roadmap

    International Nuclear Information System (INIS)

    Leach, Richard; Evans, Christopher; He, Liangyu; Davies, Angela; Duparré, Angela; Henning, Andrew; Jones, Christopher W; O’Connor, Daniel

    2015-01-01

    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 topographies, potentially providing information on both topography 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 topography 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 dynamic 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 topography 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

  7. Comment on ‘Nonlinear dynamics of a position-dependent mass-driven Duffing-type oscillator’

    International Nuclear Information System (INIS)

    Mustafa, Omar

    2013-01-01

    Using a generalized coordinate along with a proper invertible coordinate transformation, we show that the Euler–Lagrange equation used by Bagchi et al (2013 J. Phys. A: Math. Theor. 46 032001) is in clear violation of Hamilton’s principle. We also show that the Newton equation of motion they have used is not in a form that satisfies the dynamics of position-dependent mass (PDM) settings. The equivalence between the Euler–Lagrange equation and Newton’s equation is now proved and documented through the proper invertible coordinate transformation and the introduction of a new PDM byproducted reaction-type force. The total mechanical energy for the PDM is shown to be conservative (i.e., dE/dt = 0, unlike Bagchi et al's (2013) observation). (comment)

  8. A Thrust Allocation Method for Efficient Dynamic Positioning of a Semisubmersible Drilling Rig Based on the Hybrid Optimization Algorithm

    Directory of Open Access Journals (Sweden)

    Luman Zhao

    2015-01-01

    Full Text Available A thrust allocation method was proposed based on a hybrid optimization algorithm to efficiently and dynamically position a semisubmersible drilling rig. That is, the thrust allocation was optimized to produce the generalized forces and moment required while at the same time minimizing the total power consumption under the premise that forbidden zones should be taken into account. An optimization problem was mathematically formulated to provide the optimal thrust allocation by introducing the corresponding design variables, objective function, and constraints. A hybrid optimization algorithm consisting of a genetic algorithm and a sequential quadratic programming (SQP algorithm was selected and used to solve this problem. The proposed method was evaluated by applying it to a thrust allocation problem for a semisubmersible drilling rig. The results indicate that the proposed method can be used as part of a cost-effective strategy for thrust allocation of the rig.

  9. Dynamic Modeling and Nonlinear Position Control of a Quadruped Robot with Theo Jansen Linkage Mechanisms and a Single Actuator

    Directory of Open Access Journals (Sweden)

    Shunsuke Nansai

    2015-01-01

    Full Text Available The Theo Jansen mechanism is gaining widespread popularity among the legged robotics community due to its scalable design, energy efficiency, low payload-to-machine-load ratio, bioinspired locomotion, and deterministic foot trajectory. In this paper, we perform for the first time the dynamic modeling and analysis on a four-legged robot driven by a single actuator and composed of Theo Jansen mechanisms. The projection method is applied to derive the equations of motion of this complex mechanical system and a position control strategy based on energy is proposed. Numerical simulations validate the efficacy of the designed controller, thus setting a theoretical basis for further investigations on Theo Jansen based quadruped robots.

  10. Effects of nasal positive expiratory pressure on dynamic hyperinflation and 6-minute walk test in patients with COPD.

    Science.gov (United States)

    Wibmer, Thomas; Rüdiger, Stefan; Heitner, Claudia; Kropf-Sanchen, Cornelia; Blanta, Ioanna; Stoiber, Kathrin M; Rottbauer, Wolfgang; Schumann, Christian

    2014-05-01

    Dynamic hyperinflation is an important target in the treatment of COPD. There is increasing evidence that positive expiratory pressure (PEP) could reduce dynamic hyperinflation during exercise. PEP application through a nasal mask and a flow resistance device might have the potential to be used during daily physical activities as an auxiliary strategy of ventilatory assistance. The aim of this study was to determine the effects of nasal PEP on lung volumes during physical exercise in patients with COPD. Twenty subjects (mean ± SD age 69.4 ± 6.4 years) with stable mild-to-severe COPD were randomized to undergo physical exercise with nasal PEP breathing, followed by physical exercise with habitual breathing, or vice versa. Physical exercise was induced by a standard 6-min walk test (6 MWT) protocol. PEP was applied by means of a silicone nasal mask loaded with a fixed-orifice flow resistor. Body plethysmography was performed immediately pre-exercise and post-exercise. Differences in mean pre- to post-exercise changes in total lung capacity (-0.63 ± 0.80 L, P = .002), functional residual capacity (-0.48 ± 0.86 L, P = .021), residual volume (-0.56 ± 0.75 L, P = .004), S(pO2) (-1.7 ± 3.4%, P = .041), and 6 MWT distance (-30.8 ± 30.0 m, P = .001) were statistically significant between the experimental and the control interventions. The use of flow-dependent expiratory pressure, applied with a nasal mask and a PEP device, might promote significant reduction of dynamic hyperinflation during walking exercise. Further studies are warranted addressing improvements in endurance performance under regular application of nasal PEP during physical activities.

  11. SU-E-P-36: Evaluation of MLC Positioning Errors in Dynamic IMRT Treatments by Analyzing Dynalog Files

    International Nuclear Information System (INIS)

    Olasolo, J; Pellejero, S; Gracia, M; Gallardo, N; Martin, M; Lozares, S; Maneru, F; Bragado, L; Miquelez, S; Rubio, A

    2015-01-01

    Purpose: To assess the accuracy of MLC positioning in Varian linear accelerator, in dynamic IMRT technique, from the analysis of dynalog files generated by the MLC controller. Methods: In Clinac accelerators (pre-TrueBeam technology), control system has an approximately 50ms delay (one control cycle time). Then, the system compares the measured position to the planned position corresponding to the next control cycle. As it has been confirmed by Varian technical support, this effect causes that measured positions appear in dynalogs one cycle out of phase with respect to the planned positions. Around 9000 dynalogs have been analyzed, coming from the three linear accelerators of our center (one Trilogy and two Clinac 21EX) equipped with a Millennium 120 MLC. In order to compare our results to recent publications, leaf positioning errors (RMS and 95th percentile) are calculated with and without delay effect. Dynalogs have been analyzed using a in-house Matlab software. Results: The RMS errors were 0.341, 0.339 and 0.348mm for each Linac; being the average error 0.343 mm. The 95th percentiles of the error were 0.617, 0.607 and 0.625; with an average of 0.617mm. A recent multi-institution study carried out by Kerns et al. found a mean leaf RMS error of 0.32mm and a 95th percentile error value of 0.64mm.Without delay effect, mean leaf RMS errors obtained were 0.040, 0.042 and 0.038mm for each treatment machine; being the average 0.040mm. The 95th percentile error values obtained were 0.057, 0.058 and 0.054 mm, with an average of 0.056mm. Conclusion: Results obtained for the mean leaf RMS error and the mean 95th percentile were consistent with the multi-institution study. Calculated error statistics with delay effect are significantly larger due to the speed proportional and systematic leaf offset. Consequently it is proposed to correct this effect in dynalogs analysis to determine the MLC performance

  12. Dependence of fluence errors in dynamic IMRT on leaf-positional errors varying with time and leaf number

    International Nuclear Information System (INIS)

    Zygmanski, Piotr; Kung, Jong H.; Jiang, Steve B.; Chin, Lee

    2003-01-01

    In d-MLC based IMRT, leaves move along a trajectory that lies within a user-defined tolerance (TOL) about the ideal trajectory specified in a d-MLC sequence file. The MLC controller measures leaf positions multiple times per second and corrects them if they deviate from ideal positions by a value greater than TOL. The magnitude of leaf-positional errors resulting from finite mechanical precision depends on the performance of the MLC motors executing leaf motions and is generally larger if leaves are forced to move at higher speeds. The maximum value of leaf-positional errors can be limited by decreasing TOL. However, due to the inherent time delay in the MLC controller, this may not happen at all times. Furthermore, decreasing the leaf tolerance results in a larger number of beam hold-offs, which, in turn leads, to a longer delivery time and, paradoxically, to higher chances of leaf-positional errors (≤TOL). On the other end, the magnitude of leaf-positional errors depends on the complexity of the fluence map to be delivered. Recently, it has been shown that it is possible to determine the actual distribution of leaf-positional errors either by the imaging of moving MLC apertures with a digital imager or by analysis of a MLC log file saved by a MLC controller. This leads next to an important question: What is the relation between the distribution of leaf-positional errors and fluence errors. In this work, we introduce an analytical method to determine this relation in dynamic IMRT delivery. We model MLC errors as Random-Leaf Positional (RLP) errors described by a truncated normal distribution defined by two characteristic parameters: a standard deviation σ and a cut-off value Δx 0 (Δx 0 ∼TOL). We quantify fluence errors for two cases: (i) Δx 0 >>σ (unrestricted normal distribution) and (ii) Δx 0 0 --limited normal distribution). We show that an average fluence error of an IMRT field is proportional to (i) σ/ALPO and (ii) Δx 0 /ALPO, respectively, where

  13. Gravbox - The First Augmented Reality Sandbox for Gravitational Dynamics

    Science.gov (United States)

    Isbell, Jacob; Deam, Sophie; Reed, Mason; Bettis, Wyatt; Lu, Jianbo; Luppen, Zachary; Maier, Erin; McCurdy, Ross; Moore, Sadie; Fu, Hai

    2018-01-01

    Gravitational effects are an overarching theme in astronomy education, yet existing classroom demonstrations are insufficient in elucidating complex gravitational interactions. Inspired by the augmented reality (AR) sandbox developed by geologists, we have developed Gravbox, the first AR sandbox to demonstrate gravitational dynamics. The arbitrary topography of the sand surface represents the mass distribution of a two-dimensional universe. The computer reads the topography with a Kinect camera, calculates the orbit of a test particle with user-defined position and velocity, and projects the topography contour map and orbit animation with an overhead projector, all within a duty cycle of one second. This creates an interactive and intuitive tool to help students at all levels understand gravitational effects. In this contribution, we will describe the development of the Gravbox prototype and show its current capabilities. The Gravbox software will be publicly available along with a building tutorial.

  14. Integrating viscoelastic mass spring dampers into position-based dynamics to simulate soft tissue deformation in real time.

    Science.gov (United States)

    Xu, Lang; Lu, Yuhua; Liu, Qian

    2018-02-01

    We propose a novel method to simulate soft tissue deformation for virtual surgery applications. The method considers the mechanical properties of soft tissue, such as its viscoelasticity, nonlinearity and incompressibility; its speed, stability and accuracy also meet the requirements for a surgery simulator. Modifying the traditional equation for mass spring dampers (MSD) introduces nonlinearity and viscoelasticity into the calculation of elastic force. Then, the elastic force is used in the constraint projection step for naturally reducing constraint potential. The node position is enforced by the combined spring force and constraint conservative force through Newton's second law. We conduct a comparison study of conventional MSD and position-based dynamics for our new integrating method. Our approach enables stable, fast and large step simulation by freely controlling visual effects based on nonlinearity, viscoelasticity and incompressibility. We implement a laparoscopic cholecystectomy simulator to demonstrate the practicality of our method, in which liver and gallbladder deformation can be simulated in real time. Our method is an appropriate choice for the development of real-time virtual surgery applications.

  15. Older Adults with Weaker Muscle Strength Stand up from a Sitting Position with More Dynamic Trunk Use

    Directory of Open Access Journals (Sweden)

    Rob C. van Lummel

    2018-04-01

    Full Text Available The ability to stand up from a sitting position is essential for older adults to live independently. Body-fixed inertial sensors may provide an approach for quantifying the sit-to-stand (STS in clinical settings. The aim of this study was to determine whether measurements of STS movements using body-fixed sensors yield parameters that are informative regarding changes in STS performance in older adults with reduced muscle strength. In twenty-seven healthy older adults, handgrip strength was assessed as a proxy for overall muscle strength. Subjects were asked to stand up from a chair placed at three heights. Trunk movements were measured using an inertial sensor fixed to the back. Duration, angular range, and maximum angular velocity of STS phases, as well as the vertical velocity of the extension phase, were calculated. Backwards elimination using Generalized Estimating Equations was used to determine if handgrip strength predicted the STS durations and trunk kinematics. Weaker subjects (i.e., with lower handgrip strength were slower during the STS and showed a larger flexion angular range and a larger extension angular range. In addition, weaker subjects showed a greater maximum angular velocity, which increased with lower seat heights. Measurements with a single inertial sensor did reveal that older adults with lower handgrip strength employed a different strategy to stand up from a sitting position, involving more dynamic use of the trunk. This effect was greatest when elevating body mass. Trunk kinematic parameters were more sensitive to reduced muscle strength than durations.

  16. Tree Regeneration Spatial Patterns in Ponderosa Pine Forests Following Stand-Replacing Fire: Influence of Topography and Neighbors

    Directory of Open Access Journals (Sweden)

    Justin P. Ziegler

    2017-10-01

    Full Text Available Shifting fire regimes alter forest structure assembly in ponderosa pine forests and may produce structural heterogeneity following stand-replacing fire due, in part, to fine-scale variability in growing environments. We mapped tree regeneration in eighteen plots 11 to 15 years after stand-replacing fire in Colorado and South Dakota, USA. We used point pattern analyses to examine the spatial pattern of tree locations and heights as well as the influence of tree interactions and topography on tree patterns. In these sparse, early-seral forests, we found that all species were spatially aggregated, partly attributable to the influence of (1 aspect and slope on conifers; (2 topographic position on quaking aspen; and (3 interspecific attraction between ponderosa pine and other species. Specifically, tree interactions were related to finer-scale patterns whereas topographic effects influenced coarse-scale patterns. Spatial structures of heights revealed conspecific size hierarchies with taller trees in denser neighborhoods. Topography and heterospecific tree interactions had nominal effect on tree height spatial structure. Our results demonstrate how stand-replacing fires create heterogeneous forest structures and suggest that scale-dependent, and often facilitatory, rather than competitive, processes act on regenerating trees. These early-seral processes will establish potential pathways of stand development, affecting future forest dynamics and management options.

  17. Tectonics and Non-isostatic Topography of the Mariana Trench and Adjacent Plates

    Science.gov (United States)

    Hongyu, L.; Lin, J.; Zhou, Z.; Zhang, F.

    2017-12-01

    Multi-types of geophysical data including multibeam bathymetry, sediment thickness, gravity anomaly, and crustal magnetic age were analyzed to investigate tectonic processes of the Mariana Trench and the surrounding plates. We calculated non-Airy-isostatic topography by removing from the observed bathymetry the effects of sediment loading, thermal subsidence, and Airy local isostatically-compensated topography. The Mariana Trench was found to be associated with a clearly defined zone of negative non-isostatic topography, which was caused by flexural bending of the subducting Pacific plate and with the maximum depth anomaly and flexural bending near the Challenger Deep. In contrast, the Caroline Ridge and Caroline Islands Chain have much more subdued non-isostatic topography, indicating their higher topography is largely compensated by thicker crust. Along the Mariana Trough, the northern and central segments appear to be associated with relatively low magma supply as indicated by the relatively low topography and thin crust. In contrast, the southern Mariana Trough is associated with relatively high magma supply as indicated by the relatively high and smoother topography, an axial high spreading center, and relatively thick crust. The southern end of the Mariana Trough was also found to be associated with positive non-isostatic topographic anomaly, which might be caused by the complex tectonic deformation of the overriding Mariana and Philippine Sea plates and their interaction with the subducting Pacific plate. Analysis further revealed that the southern Mariana Arc, located between the Mariana Trench and Mariana Trough, is associated with positive non-isostatic topographic anomalies, which may be explained by the late stage magmatic loading on the older and thus stronger lithospheric plate of the Mariana volcanic arc.

  18. Global snowline and mountain topography: a contrasted view

    Science.gov (United States)

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

    2013-04-01

    ~40 and ~60° (or between ELA of ~500m to ~2500m a.s.l.). This mid-latitude relatively greater relief challenges the straightforward relationship between glaciations, erosion and topography. Oppositely, it suggests that glacier may be more efficient agent in temperate area, with an important amplitude between glacial and interglacial climate. This is consistent with the view of a very variable glacier erodibility that can erode and protect the landscape, as well as with studies documenting a bimodal location of the preferred glacial erosion, at relatively high elevation (around the long-term ELA), and at much lower elevation (close to the glacial maximum lower reaches), thanks to efficient water lubrication of the glacier bases that greatly enhance the sliding velocity (Herman et al., 2011). These findings show that the relation between the mountain topography and the long term snowline is not as straightforward as previously proposed (e.g. Egholm et al., 2009) . Beside the role of tectonic forcing highlighted by several authors (e.g. Pedersen et al., 2010;Spotila and Berger, 2010),, the importance of the glacial erosion appears to be crucial at mid latitude, but more complex at both high and low latitude. Moreover, the relief at mid latitude appears to be higher, hence suggesting a positive correlation between relief and topographic control of glacier on the landscape Champagnac, J.-D., Molnar, P., Sue, C., and Herman, F.: Tectonics, Climate, and Mountain Topography, Journal of Geophysical Research B: Solid Earth, 117, doi:10.1029/2011JB008348, 2012. Egholm, D. L., Nielsen, S. B., Pedersen, V. K., and Lesemann, J. E.: Glacial effects limiting mountain height, Nature, 460, 884-888, 2009. Herman, F., Beaud, F., Champagnac, J.-D., Lemieux, J.-M., and Sternai, P.: Glacial hydrology and erosion patterns: A mechanism for carving glacial valleys, Earth and Planetary Science Letters, 310, 498-508, 2011. Pedersen, V. K., Egholm, D. L., and Nielsen, S. B.: Alpine glacial

  19. Effects of elastic band exercises on physical ability and muscular topography of elderlyfemales.

    Science.gov (United States)

    Lee, Jung Won; Kim, Suk Bum; Kim, Seong Wook

    2018-02-01

    [Purpose] This study examined the effects of band exercise types on the physical ability and muscular topography for elderly females. [Subjects and Methods] Twenty-six females older than 65 years were divided into the dynamic band exercise (DBE; n=13) group and the Static band exercise (SBE; n=13) group. Each participant performed 12 weeks of elastic band exercises. Physical abilities were measured by leg extension power, sitting trunk flexion, closed eyes foot balance, and time to get up. Changes in muscle topography were evaluated with Moire measurement equipment for the chest, abdomen, and lumbar region. All results were compared before and after 12 weeks of exercise. [Results] Changes in physical ability were significantly increased in both groups. The scores for the muscular topography of the chest, abdomen, lumbar region, and all body parts was significantly improved in both groups for closed eyes foot balance. There were more improvements in the DBE group. [Conclusion] Two types of static and dynamic elastic band exercises effectively changed the physical fitness and muscle topography of elderly females. Therefore, to increase the effects of exercise, dynamic band exercises are considered useful. Because band exercises are simple, they can be used to maintain the health of elderly people.

  20. Structural Characterization of Doped GaSb Single Crystals by X-ray Topography

    Energy Technology Data Exchange (ETDEWEB)

    Honnicke, M.G.; Mazzaro, I.; Manica, J.; Benine, E.; M da Costa, E.; Dedavid, B. A.; Cusatis, C.; Huang, X. R.

    2009-09-13

    We characterized GaSb single crystals containing different dopants (Al, Cd and Te), grown by the Czochralski method, by x-ray topography and high angular resolution x-ray diffraction. Lang topography revealed dislocations parallel and perpendicular to the crystal's surface. Double-crystal GaSb 333 x-ray topography shows dislocations and vertical stripes than can be associated with circular growth bands. We compared our high-angular resolution x-ray diffraction measurements (rocking curves) with the findings predicted by the dynamical theory of x-ray diffraction. These measurements show that our GaSb single crystals have a relative variation in the lattice parameter ({Delta}d/d) on the order of 10{sup -5}. This means that they can be used as electronic devices (detectors, for example) and as x-ray monochromators.

  1. Development of DP (Dynamic Positioning) to pull-in sub sea pipelines; Utilizacao de barcos de manuseio de ancoras operando com DP (Dynamic Positioning) para arraste de dutos submarinos

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Manoel H.S. [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil); Galgoul, Elton C. [Suporte Engenharia, Luziania, GO (Brazil)

    2004-07-01

    Sub sea pipeline construction at oil and gas fields, with high concentration of on-bottom facilities, becomes more difficult when mooring operations and pipeline approach to a congested platform have to be performed. One method that has often been applied in Brazil is the so-called 'DP (Dynamic Positioning) pull-in', where PETROBRAS owned pipelay Barge, BGL-1, is moored away from the congested area, while a DP anchor handler pulls the rigid pipeline from BGL-1 to a target near the platform. The method was conceived to avoid mooring operations near the congested platforms as well as to minimize risks due to the pipeline initiation process. Inside the congested area the initiation with aid of a 'dead-man' anchor on the sea bottom, which would be a more conventional solution, becomes impossible in most cases. This paper will discuss the engineering work required to perform the 'DP pull-in' as well as show the operational steps, from the start-up to the final abandonment of the pipeline initiation head inside the target area. (author)

  2. The liberalization of the European gas sector and the strategic positioning of firms: A dynamic approach for corporate competence building

    International Nuclear Information System (INIS)

    Avadikyan, A.; Amesse, F.; Cohendet, P.; Heraud, J-A.

    2002-01-01

    A framework to explain how competitive changes occurring in one sector can affect both the dynamics of required competencies and the frontiers with adjacent sectors is proposed. When applied to the natural gas sector, the results provide a better understanding of how competencies in the sector evolve according to the new market structure and the strategic movements engaged in by the different players. The proposed framework combines the two approaches -- evolution and strategy -- to show that a firm's competencies define both membership in a specific sector and its distinctiveness from its competitors. To define the strategic positioning process the concept of core competencies is introduced, i.e. competencies developed by firms through their specific history which, when combined in a specific manner with new competencies could give them sustainable competitive advantage. Finally, the authors explain the concept of dynamic capabilities, which rely on a set of organizational and strategic processes needed to integrate, develop and create new competencies in order to initiate, or to adapt to market changes. The final conclusion is that the recent liberalization of the European gas and power sectors weakened institutional entry barriers, a phenomenon which compelled operators traditionally protected by regional or national monopolies to compete with other potential actors. With specific reference to the gas, power and oil industries it is stated that if they had relatively clear frontiers in the past, these frontiers have now become increasingly permeable. However, this weakening of institutional barriers has a beneficial consequence: it allows companies to deploy strategies to take advantage of new growth and rent appropriation opportunities. Examples of adaptation by European oil companies, power companies and natural gas firms are used to illustrate the principles embodied in the proposed framework. 18 refs., 1 fig

  3. Historical development of synchrotron x-ray diffraction topography

    International Nuclear Information System (INIS)

    Kawado, Seiji

    2011-01-01

    After a short history of X-ray diffraction topography, from the early stage of laboratory X-ray topography to recent synchrotron-radiation applications, is described, the development of science and technology for the synchrotron X-ray topography and its industrial applications are reviewed in more detail. In addition, the recent trend to synchrotron topography research is clarified on the basis of several data obtained from 256 papers which have been published since 2000. (author)

  4. Position encoder

    International Nuclear Information System (INIS)

    Goursky, Vsevolod

    1975-01-01

    A circuitry for deriving the quotient of signal delivered by position-sensitive detectors is described. Digital output is obtained in the form of 10- to 12-bit words. Impact position may be determined with 0.25% accuracy when the dynamic range of the energy signal is less 1:10, and 0.5% accuracy when the dynamic range is 1:20. The division requires an average time of 5μs for 10-bit words

  5. Position encoder

    International Nuclear Information System (INIS)

    Goursky, V.

    1975-05-01

    This paper describes circuitry for deriving the quotient of signals delivered by position-sensitive detectors. Digital output is obtained in the form of 10 to 12 bit words. Impact position may be determined with 0.25% accuracy when the dynamic range of the energy signal is less than 1:10, and 0.5% accuracy when the dynamic range is 1:20. The division requires an average time of 5μs for 10-bit words [fr

  6. Modeling economic costs of disasters and recovery involving positive effects of reconstruction: analysis using a dynamic CGE model

    Science.gov (United States)

    Xie, W.; Li, N.; Wu, J.-D.; Hao, X.-L.

    2013-11-01

    Disaster damages have negative effects on economy, whereas reconstruction investments have positive effects. The aim of this study is to model economic causes of disasters and recovery involving positive effects of reconstruction activities. Computable general equilibrium (CGE) model is a promising approach because it can incorporate these two kinds of shocks into a unified framework and further avoid double-counting problem. In order to factor both shocks in CGE model, direct loss is set as the amount of capital stock reduced on supply side of economy; A portion of investments restore the capital stock in existing period; An investment-driven dynamic model is formulated due to available reconstruction data, and the rest of a given country's saving is set as an endogenous variable. The 2008 Wenchuan Earthquake is selected as a case study to illustrate the model, and three scenarios are constructed: S0 (no disaster occurs), S1 (disaster occurs with reconstruction investment) and S2 (disaster occurs without reconstruction investment). S0 is taken as business as usual, and the differences between S1 and S0 and that between S2 and S0 can be interpreted as economic losses including reconstruction and excluding reconstruction respectively. The study showed that output from S1 is found to be closer to real data than that from S2. S2 overestimates economic loss by roughly two times that under S1. The gap in economic aggregate between S1 and S0 is reduced to 3% in 2011, a level that should take another four years to achieve under S2.

  7. Description of two-process surface topography

    International Nuclear Information System (INIS)

    Grabon, W; Pawlus, P

    2014-01-01

    After two machining processes, a large number of surface topography measurements were made using Talyscan 150 stylus measuring equipment. The measured samples were divided into two groups. The first group contained two-process surfaces of random nature, while the second group used random-deterministic textures of random plateau parts and portions of deterministic valleys. For comparison, one-process surfaces were also analysed. Correlation and regression analysis was used to study the dependencies among surface texture parameters in 2D and 3D systems. As the result of this study, sets of parameters describing multi-process surface topography were obtained for two-process surfaces of random and of random-deterministic types. (papers)

  8. A consistent data set of Antarctic ice sheet topography, cavity geometry, and global bathymetry

    Directory of Open Access Journals (Sweden)

    R. Timmermann

    2010-12-01

    Full Text Available Sub-ice shelf circulation and freezing/melting rates in ocean general circulation models depend critically on an accurate and consistent representation of cavity geometry. Existing global or pan-Antarctic topography data sets have turned out to contain various inconsistencies and inaccuracies. The goal of this work is to compile independent regional surveys and maps into a global data set. We use the S-2004 global 1-min bathymetry as the backbone and add an improved version of the BEDMAP topography (ALBMAP bedrock topography for an area that roughly coincides with the Antarctic continental shelf. The position of the merging line is individually chosen in different sectors in order to capture the best of both data sets. High-resolution gridded data for ice shelf topography and cavity geometry of the Amery, Fimbul, Filchner-Ronne, Larsen C and George VI Ice Shelves, and for Pine Island Glacier are carefully merged into the ambient ice and ocean topographies. Multibeam survey data for bathymetry in the former Larsen B cavity and the southeastern Bellingshausen Sea have been obtained from the data centers of Alfred Wegener Institute (AWI, British Antarctic Survey (BAS and Lamont-Doherty Earth Observatory (LDEO, gridded, and blended into the existing bathymetry map. The resulting global 1-min Refined Topography data set (RTopo-1 contains self-consistent maps for upper and lower ice surface heights, bedrock topography, and surface type (open ocean, grounded ice, floating ice, bare land surface. The data set is available in NetCDF format from the PANGAEA database at doi:10.1594/pangaea.741917.

  9. An agent-based model contrasts opposite effects of dynamic and stable microtubules on cleavage furrow positioning.

    Science.gov (United States)

    Odell, Garrett M; Foe, Victoria E

    2008-11-03

    From experiments by Foe and von Dassow (Foe, V.E., and G. von Dassow. 2008. J. Cell Biol. 183:457-470) and others, we infer a molecular mechanism for positioning the cleavage furrow during cytokinesis. Computer simulations reveal how this mechanism depends on quantitative motor-behavior details and explore how robustly this mechanism succeeds across a range of cell sizes. The mechanism involves the MKLP1 (kinesin-6) component of centralspindlin binding to and walking along microtubules to stimulate cortical contractility where the centralspindlin complex concentrates. The majority of astral microtubules are dynamically unstable. They bind most MKLP1 and suppress cortical Rho/myosin II activation because the tips of unstable microtubules usually depolymerize before MKLP1s reach the cortex. A subset of astral microtubules stabilizes during anaphase, becoming effective rails along which MKLP1 can actually reach the cortex. Because stabilized microtubules aim statistically at the equatorial spindle midplane, that is where centralspindlin accumulates to stimulate furrow formation.

  10. Peptide insertion, positioning, and stabilization in a membrane: insight from an all-atom molecular dynamics simulation.

    Science.gov (United States)

    Babakhani, Arneh; Gorfe, Alemayehu A; Gullingsrud, Justin; Kim, Judy E; Andrew McCammon, J

    Peptide insertion, positioning, and stabilization in a model membrane are probed via an all-atom molecular dynamics (MD) simulation. One peptide (WL5) is simulated in each leaflet of a solvated dimyristoylglycero-3-phosphate (DMPC) membrane. Within the first 5 ns, the peptides spontaneously insert into the membrane and then stabilize during the remaining 70 ns of simulation time. In both leaflets, the peptides localize to the membrane interface, and this localization is attributed to the formation of peptide-lipid hydrogen bonds. We show that the single tryptophan residue in each peptide contributes significantly to these hydrogen bonds; specifically, the nitrogen heteroatom of the indole ring plays a critical role. The tilt angles of the indole rings relative to the membrane normal in the upper and lower leaflets are approximately 26 degrees and 54 degrees , respectively. The tilt angles of the entire peptide chain are 62 degrees and 74 degrees . The membrane induces conformations of the peptide that are characteristic of beta-sheets, and the peptide enhances the lipid ordering in the membrane. Finally, the diffusion rate of the peptides in the membrane plane is calculated (based on experimental peptide concentrations) to be approximately 6 A(2)/ns, thus suggesting a 500 ns time scale for intermolecular interactions.

  11. Spike voltage topography in temporal lobe epilepsy.

    Science.gov (United States)

    Asadi-Pooya, Ali A; Asadollahi, Marjan; Shimamoto, Shoichi; Lorenzo, Matthew; Sperling, Michael R

    2016-07-15

    We investigated the voltage topography of interictal spikes in patients with temporal lobe epilepsy (TLE) to see whether topography 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 topography 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 topography 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. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Topography of the Moon from the Clementine Lidar

    Science.gov (United States)

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

    1997-01-01

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

  13. Examinations for quantifying the difference in radiation doses at the least favorable locations between facility sites in highly structured topographies (valleys) and in plane terrain (licensing procedures)

    International Nuclear Information System (INIS)

    Raskob, W.

    1995-01-01

    The MCF wind field model and the LASAT Lagrange particle model served to study topography effects on the spreading of radionuclides. Concentrations in bottom layers of the atmosphere at maximum-dose positions in hilly country topography are up to a factor 6 higher than in plain country. For concentrations in the soil the results have a similar relation. (orig.)

  14. Coastal Dynamics

    NARCIS (Netherlands)

    Roelvink, J.A.; Steetzel, H.J.; Bliek, A.; Rakhorst, H.D.; Roelse, P.; Bakker, W.T.

    1998-01-01

    This book deals on "Coastal Dynamics", which will be defined in a narrow sense as a mathematical theory, which starts from given equations of motion for the sediment, which leads with the continuity equation and given boundary conditions to a calculated (eventually schematized) coastal topography,

  15. Refining the ischemic penumbra with topography.

    Science.gov (United States)

    Thirugnanachandran, Tharani; Ma, Henry; Singhal, Shaloo; Slater, Lee-Anne; Davis, Stephen M; Donnan, Geoffrey A; Phan, Thanh

    2018-04-01

    It has been 40 years since the ischemic penumbra was first conceptualized through work on animal models. The topography of penumbra has been portrayed as an infarcted core surrounded by penumbral tissue and an extreme rim of oligemic tissue. This picture has been used in many review articles and textbooks before the advent of modern imaging. In this paper, we review our understanding of the topography of the ischemic penumbra from the initial experimental animal models to current developments with neuroimaging which have helped to further define the temporal and spatial evolution of the penumbra and refine our knowledge. The concept of the penumbra has been successfully applied in clinical trials of endovascular therapies with a time window as long as 24 h from onset. Further, there are reports of "good" outcome even in patients with a large ischemic core. This latter observation of good outcome despite having a large core requires an understanding of the topography of the penumbra and the function of the infarcted regions. It is proposed that future research in this area takes departure from a time-dependent approach to a more individualized tissue and location-based approach.

  16. Lunar Topography: Results from the Lunar Orbiter Laser Altimeter

    Science.gov (United States)

    Neumann, Gregory; Smith, David E.; Zuber, Maria T.; Mazarico, Erwan

    2012-01-01

    The Lunar Orbiter Laser Altimeter (LOLA) onboard the Lunar Reconnaissance Orbiter (LRO) has been operating nearly continuously since July 2009, accumulating over 6 billion measurements from more than 2 billion in-orbit laser shots. LRO's near-polar orbit results in very high data density in the immediate vicinity of the lunar poles, with full coverage at the equator from more than 12000 orbital tracks averaging less than 1 km in spacing at the equator. LRO has obtained a global geodetic model of the lunar topography with 50-meter horizontal and 1-m radial accuracy in a lunar center-of-mass coordinate system, with profiles of topography at 20-m horizontal resolution, and 0.1-m vertical precision. LOLA also provides measurements of reflectivity and surface roughness down to its 5-m laser spot size. With these data LOLA has measured the shape of all lunar craters 20 km and larger. In the proposed extended mission commencing late in 2012, LOLA will concentrate observations in the Southern Hemisphere, improving the density of the polar coverage to nearly 10-m pixel resolution and accuracy to better than 20 m total position error. Uses for these data include mission planning and targeting, illumination studies, geodetic control of images, as well as lunar geology and geophysics. Further improvements in geodetic accuracy are anticipated from the use of re ned gravity fields after the successful completion of the Gravity Recovery and Interior Laboratory (GRAIL) mission in 2012.

  17. Effect of topography on wind turbine power and load fluctuations

    Science.gov (United States)

    Santoni, Christian; Ciri, Umberto; Leonardi, Stefano

    2015-11-01

    Onshore wind turbines produce more than 17 GW in the US, which constitutes 4 . 4 % of all the energy produced. Sites selection is mostly determined by the atmospheric conditions and the topographical characteristics of the region. While the effect of the atmospheric boundary layer had been widely studied, less attention has been given to the effect of the topography on the wind turbine aerodynamics. To address how the topography affects the flow, Large Eddy Simulations of the flow over a wind turbine placed over wavy wall are performed. The wavelength of the wavy terrain, λ, is 1 . 7 D where D is the turbine rotor diameter. Two different values of the height of the wavy wall, a / D = 0 . 05 and a / D = 0 . 10 have been considered. In addition, two positions of the turbine with respect to the wavy wall had been studied, on the crest and trough of the wavy wall and compared with a wind turbine over a flat wall. For the turbine located at the crest, the pressure gradient due to the wavy wall caused a recirculation behind the wind tower 2 . 5 D larger than that of the smooth wall. When placed at the trough of the wavy terrain, the favorable pressure gradient increases the wake velocity near the wall and promotes entrainment into the turbine wake. Numerical simulations were performed on XSEDE TACC, Grant CTS070066. This work was supported by the NSF, grant IIA-1243482 (WINDINSPIRE).

  18. Topography-modified refraction: adjustment of treated cylinder amount and axis to the topography versus standard clinical refraction in myopic topography-guided LASIK

    OpenAIRE

    Alpins, Noel

    2017-01-01

    Noel Alpins1,2 1NewVision Clinics, Melbourne, VIC, Australia; 2Department Ophthalmology, Melbourne University, Melbourne, VIC, Australia It is encouraging to see the results in the article by Kanellopoulos “Topography-modified refraction (TMR): adjustment of treated cylinder amount and axis to the topography versus standard clinical refraction in myopic topography-guided LASIK”,1 where the combination of refractive and corneal data in the treatment parameters pro...

  19. OpenTopography: Enabling Online Access to High-Resolution Lidar Topography Data and Processing Tools

    Science.gov (United States)

    Crosby, Christopher; Nandigam, Viswanath; Baru, Chaitan; Arrowsmith, J. Ramon

    2013-04-01

    High-resolution topography 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 OpenTopography Facility (http://www.opentopography.org) is a web-based system designed to democratize access to earth science-oriented lidar topography data. OpenTopography 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 OpenTopography 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. OpenTopography 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 OpenTopography. 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. OpenTopography has become a hub for high-resolution topography

  20. Top-down topography of deeply etched silicon in the scanning electron microscope

    International Nuclear Information System (INIS)

    Wells, Oliver C.; Murray, Conal E.; Rullan, Jonathan L.; Gignac, Lynne M.

    2004-01-01

    It is proposed to measure the cross sections of steep-sided etched lines and similar deep surface topography on partially completed silicon integrated circuit wafers using either the backscattered electron (BSE) or the low-loss electron (LLE) image in the scanning electron microscope (SEM). These images contain regions where the collected signal is zero because there is no direct line of sight between the landing point of the electron beam on the specimen and the BSE or LLE detector. It is proposed to use the boundary of such a region in the SEM image as a geometrical line to measure the surface topography. Or alternatively, a shadow can be seen in the distribution of either BSE or LLE with an image-forming detector system. The use of this shadow position on the detector to measure deep surface topography will be demonstrated

  1. Geophysical, petrological and mineral physics constraints on Earth's surface topography

    Science.gov (United States)

    Guerri, Mattia; Cammarano, Fabio; Tackley, Paul J.

    2015-04-01

    Earth's surface topography is controlled by isostatically compensated density variations within the lithosphere, but dynamic topography - i.e. the topography 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

  2. DNA dynamics play a role as a basal transcription factor in the positioning and regulation of gene transcription initiation

    OpenAIRE

    Alexandrov, Boian S.; Gelev, Vladimir; Yoo, Sang Wook; Alexandrov, Ludmil B.; Fukuyo, Yayoi; Bishop, Alan R.; Rasmussen, Kim ?.; Usheva, Anny

    2009-01-01

    We assess the role of DNA breathing dynamics as a determinant of promoter strength and transcription start site (TSS) location. We compare DNA Langevin dynamic profiles of representative gene promoters, calculated with the extended non-linear PBD model of DNA with experimental data on transcription factor binding and transcriptional activity. Our results demonstrate that DNA dynamic activity at the TSS can be suppressed by mutations that do not affect basal transcription factor binding–DNA co...

  3. Learning From Philadelphia: Topographies of HIV/AIDS Media Assemblages.

    Science.gov (United States)

    Cartwright, Lisa

    2016-01-01

    For this contribution to the special issue on "Mapping Queer Bioethics," the author employs an array of public health and popular media texts (especially Jonathan Demme's film Philadelphia) to challenge the construction and reconstruction of HIV-positive bodies as sites of bioethical concern. In outlining notions of "digital restoration," the author argues that there has been of late a remapping of the first decade of the HIV/AIDS pandemic through media projects assembled from archived materials. Accordingly, the author suggests that in the first decades of the 2000s, we have witnessed a media-archaeological turn, whereby old materials have been reassembled for commemorative purposes that oftentimes perform a reshaping of the topography of the first decade of the AIDS pandemic.

  4. Learning topography with Tangible Landscape games

    Science.gov (United States)

    Petrasova, A.; Tabrizian, P.; Harmon, B. A.; Petras, V.; Millar, G.; Mitasova, H.; Meentemeyer, R. K.

    2017-12-01

    Understanding topography and its representations is crucial for correct interpretation and modeling of surface processes. However, novice earth science and landscape architecture students often find reading topographic maps challenging. As a result, many students struggle to comprehend more complex spatial concepts and processes such as flow accumulation or sediment transport.We developed and tested a new method for teaching hydrology, geomorphology, and grading using Tangible Landscape—a tangible interface for geospatial modeling. Tangible Landscape couples a physical and digital model of a landscape through a real-time cycle of hands-on modeling, 3D scanning, geospatial computation, and projection. With Tangible Landscape students can sculpt a projection-augmented topographic model of a landscape with their hands and use a variety of tangible objects to immediately see how they are changing geospatial analytics such as contours, profiles, water flow, or landform types. By feeling and manipulating the shape of the topography, while seeing projected geospatial analytics, students can intuitively learn about 3D topographic form, its representations, and how topography controls physical processes. Tangible Landscape is powered by GRASS GIS, an open source geospatial platform with extensive libraries for geospatial modeling and analysis. As such, Tangible Landscape can be used to design a wide range of learning experiences across a large number of geoscience disciplines.As part of a graduate level course that teaches grading, 16 students participated in a series of workshops, which were developed as serious games to encourage learning through structured play. These serious games included 1) diverting rain water to a specified location with minimal changes to landscape, 2) building different combinations of landforms, and 3) reconstructing landscapes based on projected contour information with feedback.In this poster, we will introduce Tangible Landscape, and

  5. Synchrotron-radiation plane-wave topography

    International Nuclear Information System (INIS)

    Riglet, P.; Sauvage, M.; Petroff, J.F.; Epelboin, Y.

    1980-01-01

    A computer program based on the Takagi-Taupin differential equations for X-ray propagation in distorted crystals has been developed in order to simulate dislocation images in the Bragg case. The program is valid both for thin and thick crystals. Simulated images of misfit dislocations formed either in a thin epilayer or in a thick substrate are compared with experimental images obtained by synchrotron-radiation plane-wave topography. The influence of the various strain components on the image features is discussed. (author)

  6. Welcome to Surface Topography: Metrology and Properties

    Science.gov (United States)

    Leach, Richard

    2013-11-01

    I am delighted to welcome readers to this inaugural issue of Surface Topography: 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 topography 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 topography 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 Topography: 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

  7. Earth's structure and evolution inferred from topography, gravity, and seismicity.

    Science.gov (United States)

    Watkinson, A. J.; Menard, J.; Patton, R. L.

    2016-12-01

    Earth's wavelength-dependent response to loading, reflected in observed topography, gravity, and seismicity, can be interpreted in terms of a stack of layers under the assumption of transverse isotropy. The theory of plate tectonics holds that the outermost layers of this stack are mobile, produced at oceanic ridges, and consumed at subduction zones. Their toroidal motions are generally consistent with those of several rigid bodies, except in the world's active mountain belts where strains are partitioned and preserved in tectonite fabrics. Even portions of the oceanic lithosphere exhibit non-rigid behavior. Earth's gravity-topography cross-spectrum exhibits notable variations in signal amplitude and character at spherical harmonic degrees l=13, 116, 416, and 1389. Corresponding Cartesian wavelengths are approximately equal to the respective thicknesses of Earth's mantle, continental mantle lithosphere, oceanic thermal lithosphere, and continental crust, all known from seismology. Regional variations in seismic moment release with depth, derived from the global Centroid Moment Tensor catalog, are also evident in the crust and mantle lithosphere. Combined, these observations provide powerful constraints for the structure and evolution of the crust, mantle lithosphere, and mantle as a whole. All that is required is a dynamically consistent mechanism relating wavelength to layer thickness and shear-strain localization. A statistically-invariant 'diharmonic' relation exhibiting these properties appears as the leading order approximation to toroidal motions on a self-gravitating body of differential grade-2 material. We use this relation, specifically its predictions of weakness and rigidity, and of folding and shear banding response as a function of wavelength-to-thickness ratio, to interpret Earth's gravity, topography, and seismicity in four-dimensions. We find the mantle lithosphere to be about 255-km thick beneath the Himalaya and the Andes, and the long

  8. River bathymetry estimation based on the floodplains topography.

    Science.gov (United States)

    Bureš, Luděk; Máca, Petr; Roub, Radek; Pech, Pavel; Hejduk, Tomáš; Novák, Pavel

    2017-04-01

    capacity and monitor the amount and dynamics of sediments) and Internal Grant Agency of Faculty of Environmental Sciences (CULS) (IGA/20164233). Keywords: bathymetry, global optimization, bed topography References: Merwade, Venkatesh. "Effect of spatial trends on interpolation of river bathymetry." Journal of Hydrology, 371.1, 169-181, 2009. Legleiter, Carl J., and Phaedon C. Kyriakidis. Spatial prediction of river channel topography by kriging. Earth Surface Processes and Landforms, 33.6 , 841-867, 2008. P. Maca and P. Pech and and J. Pavlasek. Comparing the Selected Transfer Functions and Local Optimization Methods for Neural Network Flood Runoff Forecast. Mathematical Problems in Engineering, vol. 2014, Article ID 782351, 10 pages, 2014. M. Jakubcova and P. Maca and and P. Pech. A Comparison of Selected Modifications of the Particle Swarm Optimization Algorithm. Journal of Applied Mathematics, vol. 2014, Article ID 293087, 10 pages, 2014.

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

    Science.gov (United States)

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

    2016-01-13

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

  10. Brain function measurement using optical topography

    International Nuclear Information System (INIS)

    Koizumi, Hideaki; Maki, Atsushi; Yamamoto, Tsuyoshi; Kawaguchi, Hideo

    2003-01-01

    Optical topography is a completely non-invasive method to image the high brain function with the near infrared spectroscopy, does not need the restriction of human behavior for imaging and thereby is applicable even for infants. The principle is based on irradiation of the near infrared laser beam with the optical-fiber onto the head surface and detection with the fiber of the reflection, of which spectroscopy for blood-borne hemoglobin gives the local cerebral homodynamics related with the nerve activity. The infrared laser beam of 1-10 mW is found safe on direct irradiation to the human body. The topography is applicable in the fields of clinical medicine like internal neurology (an actual image of the activated Broca's and Welnicke's areas at writing is presented), neurosurgery, psychiatry and pedriatric neurology, of developmental cognitive neuroscience, of educational science and of communication. ''MIT Technology Reviews'' mentions that this technique is one of 4 recent promising innovative techniques in the world. (N.I.)

  11. Altered Global Signal Topography in Schizophrenia.

    Science.gov (United States)

    Yang, Genevieve J; Murray, John D; Glasser, Matthew; Pearlson, Godfrey D; Krystal, John H; Schleifer, Charlie; Repovs, Grega; Anticevic, Alan

    2017-11-01

    Schizophrenia (SCZ) is a disabling neuropsychiatric disease associated with disruptions across distributed neural systems. Resting-state functional magnetic resonance imaging has identified extensive abnormalities in the blood-oxygen level-dependent signal in SCZ patients, including alterations in the average signal over the brain-i.e. the "global" signal (GS). It remains unknown, however, if these "global" alterations occur pervasively or follow a spatially preferential pattern. This study presents the first network-by-network quantification of GS topography in healthy subjects and SCZ patients. We observed a nonuniform GS contribution in healthy comparison subjects, whereby sensory areas exhibited the largest GS component. In SCZ patients, we identified preferential GS representation increases across association regions, while sensory regions showed preferential reductions. GS representation in sensory versus association cortices was strongly anti-correlated in healthy subjects. This anti-correlated relationship was markedly reduced in SCZ. Such shifts in GS topography may underlie profound alterations in neural information flow in SCZ, informing development of pharmacotherapies. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  12. Snap evaporation of droplets on smooth topographies.

    Science.gov (United States)

    Wells, Gary G; Ruiz-Gutiérrez, Élfego; Le Lirzin, Youen; Nourry, Anthony; Orme, Bethany V; Pradas, Marc; Ledesma-Aguilar, Rodrigo

    2018-04-11

    Droplet evaporation on solid surfaces is important in many applications including printing, micro-patterning and cooling. While seemingly simple, the configuration of evaporating droplets on solids is difficult to predict and control. This is because evaporation typically proceeds as a "stick-slip" sequence-a combination of pinning and de-pinning events dominated by static friction or "pinning", caused by microscopic surface roughness. Here we show how smooth, pinning-free, solid surfaces of non-planar topography promote a different process called snap evaporation. During snap evaporation a droplet follows a reproducible sequence of configurations, consisting of a quasi-static phase-change controlled by mass diffusion interrupted by out-of-equilibrium snaps. Snaps are triggered by bifurcations of the equilibrium droplet shape mediated by the underlying non-planar solid. Because the evolution of droplets during snap evaporation is controlled by a smooth topography, and not by surface roughness, our ideas can inspire programmable surfaces that manage liquids in heat- and mass-transfer applications.

  13. Functional analysis screening for multiple topographies of problem behavior.

    Science.gov (United States)

    Bell, Marlesha C; Fahmie, Tara A

    2018-04-23

    The current study evaluated a screening procedure for multiple topographies of problem behavior in the context of an ongoing functional analysis. Experimenters analyzed the function of a topography of primary concern while collecting data on topographies of secondary concern. We used visual analysis to predict the function of secondary topographies and a subsequent functional analysis to test those predictions. Results showed that a general function was accurately predicted for five of six (83%) secondary topographies. A specific function was predicted and supported for a subset of these topographies. The experimenters discuss the implication of these results for clinicians who have limited time for functional assessment. © 2018 Society for the Experimental Analysis of Behavior.

  14. Simultaneous topography imaging and broadband nanomechanical mapping on atomic force microscope

    Science.gov (United States)

    Li, Tianwei; Zou, Qingze

    2017-12-01

    In this paper, an approach is proposed to achieve simultaneous imaging and broadband nanomechanical mapping of soft materials in air by using an atomic force microscope. Simultaneous imaging and nanomechanical mapping are needed, for example, to correlate the morphological and mechanical evolutions of the sample during dynamic phenomena such as the cell endocytosis process. Current techniques for nanomechanical mapping, however, are only capable of capturing static elasticity of the material, or the material viscoelasticity in a narrow frequency band around the resonant frequency(ies) of the cantilever used, not competent for broadband nanomechanical mapping, nor acquiring topography image of the sample simultaneously. These limitations are addressed in this work by enabling the augmentation of an excitation force stimuli of rich frequency spectrum for nanomechanical mapping in the imaging process. Kalman-filtering technique is exploited to decouple and split the mixed signals for imaging and mapping, respectively. Then the sample indentation generated is quantified online via a system-inversion method, and the effects of the indentation generated and the topography tracking error on the topography quantification are taken into account. Moreover, a data-driven feedforward-feedback control is utilized to track the sample topography. The proposed approach is illustrated through experimental implementation on a polydimethylsiloxane sample with a pre-fabricated pattern.

  15. X-ray diffraction topography. Stages and tendencies of development

    International Nuclear Information System (INIS)

    Shul'pina, I.L.

    2000-01-01

    The physical foundation of X-ray diffraction topography, its methods, the achievements in image theory, the stages of evolution were described in this review. It was found that modern topography is well along in development associated with the use of third-generation synchrotron radiation and with its adaptation to advance materials and problems of materials science. Some proposals about prospects for X-ray topography progress in the future have been made [ru

  16. Gravity Terrain Effect of the Seafloor Topography in Taiwan

    Directory of Open Access Journals (Sweden)

    Lun-Tao Tong Tai-Rong Guo

    2007-01-01

    Full Text Available Gravity terrain correction is used to compensate for the gravitational effects of the topography residual to the Bouguer plate. The seafloor topography off the eastern offshore of Taiwan is extremely rugged, and the depth of the sea bottom could be greater than 5000 m. In order to evaluate the terrain effect caused by the seafloor topography, a modern computer algorithm is used to calculate the terrain correction based on the digital elevation model (DEM.

  17. Managing the explosion of high resolution topography in the geosciences

    Science.gov (United States)

    Crosby, Christopher; Nandigam, Viswanath; Arrowsmith, Ramon; Phan, Minh; Gross, Benjamin

    2017-04-01

    Centimeter to decimeter-scale 2.5 to 3D sampling of the Earth surface topography coupled with the potential for photorealistic coloring of point clouds and texture mapping of meshes enables a wide range of science applications. Not only is the configuration and state of the surface as imaged valuable, but repeat surveys enable quantification of topographic change (erosion, deposition, and displacement) caused by various geologic processes. We are in an era of ubiquitous point clouds that come from both active sources such as laser scanners and radar as well as passive scene reconstruction via structure from motion (SfM) photogrammetry. With the decreasing costs of high-resolution topography (HRT) data collection, via methods such as SfM and UAS-based laser scanning, the number of researchers collecting these data is increasing. These "long-tail" topographic data are of modest size but great value, and challenges exist to making them widely discoverable, shared, annotated, cited, managed and archived. Presently, there are no central repositories or services to support storage and curation of these datasets. The U.S. National Science Foundation funded OpenTopography (OT) Facility employs cyberinfrastructure including large-scale data management, high-performance computing, and service-oriented architectures, to provide efficient online access to large HRT (mostly lidar) datasets, metadata, and processing tools. With over 225 datasets and 15,000 registered users, OT is well positioned to provide curation for community collected high-resolution topographic data. OT has developed a "Community DataSpace", a service built on a low cost storage cloud (e.g. AWS S3) to make it easy for researchers to upload, curate, annotate and distribute their datasets. The system's ingestion workflow will extract metadata from data uploaded; validate it; assign a digital object identifier (DOI); and create a searchable catalog entry, before publishing via the OT portal. The OT Community

  18. DMPD: When signaling pathways collide: positive and negative regulation of toll-likereceptor signal transduction. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 18631453 When signaling pathways collide: positive and negative regulation of toll-...uction. PubmedID 18631453 Title When signaling pathways collide: positive and neg...l) Show When signaling pathways collide: positive and negative regulation of toll-likereceptor signal transd...likereceptor signal transduction. O'Neill LA. Immunity. 2008 Jul 18;29(1):12-20. (.png) (.svg) (.html) (.csm

  19. Origin of bending in uncoated microcantilever - Surface topography?

    International Nuclear Information System (INIS)

    Lakshmoji, K.; Prabakar, K.; Tripura Sundari, S.; Jayapandian, J.; Tyagi, A. K.; Sundar, C. S.

    2014-01-01

    We provide direct experimental evidence to show that difference in surface topography 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 topography shows a difference of 73° between the opposite sides. The absence of deflection in another uncoated microcantilever having similar surface topography confirms that in former microcantilever bending is indeed induced by differences in surface topography

  20. Smoking Through a Topography Device Diminishes Some of the Acute Rewarding Effects of Smoking.

    Science.gov (United States)

    Ross, Kathryn C; Juliano, Laura M

    2016-05-01

    Smoking topography (ST) devices are an important methodological tool for quantifying puffing behavior (eg, puff volume, puff velocity) as well as identifying puffing differences across individuals and situations. Available ST devices are designed such that the smoker's mouth and hands have direct contact with the device rather than the cigarette itself. Given the importance of the sensorimotor aspects of cigarette smoking in smoking reward, it is possible that ST devices may interfere with the acute rewarding effects of smoking. Despite the methodological importance of this issue, few studies have directly compared subjective reactions to smoking through a topography device to naturalistic smoking. Smokers (N = 58; 38% female) smoked their preferred brand of cigarettes one time through a portable topography device and one time naturalistically, in counterbalanced order across two laboratory sessions. Smoking behavior (eg, number of puffs) and subjective effects (eg, urge reduction, affect, smoking satisfaction) were assessed. Negative affect reduction was greater in the natural smoking condition relative to the topography condition, but differences were not significant on measures of urge, withdrawal, or positive affect. Self-reported smoking satisfaction, enjoyment of respiratory tract sensations, psychological reward, craving reduction, and other rewarding effects of smoking were also significantly greater in the naturalistic smoking condition. The effects of using a ST device on the smoking experience should be considered when it is used in research as it may diminish some of the rewarding effects of smoking. When considering the inclusion of a smoking topography device in one's research, it is important to know if use of that device will alter the smoker's experience. This study assessed affective and subjective reactions to smoking through a topography device compared to naturalistic smoking. We found that smoking satisfaction, psychological reward, enjoyment

  1. A noncontact laser system for measuring soil surface topography

    International Nuclear Information System (INIS)

    Huang, C.; White, I.; Thwaite, E.G.; Bendeli, A.

    1988-01-01

    Soil surface topography profoundly influences runoff hydrodynamics, soil erosion, and surface retention of water. Here we describe an optical noncontact system for measuring soil surface topography. Soil elevation is measured by projecting a laser beam onto the surface and detecting the position of the interception point. The optical axis of the detection system is oriented at a small angle to the incident beam. A low-power HeNe (Helium-Neon) laser is used as the laser source, a photodiode array is used as the laser image detector and an ordinary 35-mm single lens reflex camera provides the optical system to focus the laser image onto the diode array. A wide spectrum of measurement ranges (R) and resolutions are selectable, from 1 mm to 1 m. These are determined by the laser-camera distance and angle, the focal length of the lens, and the sensing length of the diode array and the number of elements (N) contained in the array. The resolution of the system is approximately R/2N. We show for the system used here that this resolution is approximately 0.2%. In the configuration selected, elevation changes of 0.16 mm could be detected over a surface elevation range of 87 mm. The sampling rate of the system is 1000 Hz, which permits soil surfaces to be measured at speeds of up to 1 m s −1 with measurements taken at 1-mm spacing. Measurements of individual raindrop impacts on the soil and of soil surfaces before and after rain show the versatility of the laser surface profiler, which has applications in studies of erosion processes, surface storage and soil trafficability

  2. Pre-LGM Northern Hemisphere ice sheet topography

    Directory of Open Access Journals (Sweden)

    J. Kleman

    2013-10-01

    Full Text Available We here reconstruct the paleotopography of Northern Hemisphere ice sheets during the glacial maxima of marine isotope stages (MIS 5b and 4.We employ a combined approach, blending geologically based reconstruction and numerical modeling, to arrive at probable ice sheet extents and topographies for each of these two time slices. For a physically based 3-D calculation based on geologically derived 2-D constraints, we use the University of Maine Ice Sheet Model (UMISM to calculate ice sheet thickness and topography. The approach and ice sheet modeling strategy is designed to provide robust data sets of sufficient resolution for atmospheric circulation experiments for these previously elusive time periods. Two tunable parameters, a temperature scaling function applied to a spliced Vostok–GRIP record, and spatial adjustment of the climatic pole position, were employed iteratively to achieve a good fit to geological constraints where such were available. The model credibly reproduces the first-order pattern of size and location of geologically indicated ice sheets during marine isotope stages (MIS 5b (86.2 kyr model age and 4 (64 kyr model age. From the interglacial state of two north–south obstacles to atmospheric circulation (Rocky Mountains and Greenland, by MIS 5b the emergence of combined Quebec–central Arctic and Scandinavian–Barents-Kara ice sheets had increased the number of such highland obstacles to four. The number of major ice sheets remained constant through MIS 4, but the merging of the Cordilleran and the proto-Laurentide Ice Sheet produced a single continent-wide North American ice sheet at the LGM.

  3. BedMachine v3: Complete Bed Topography and Ocean Bathymetry Mapping of Greenland From Multibeam Echo Sounding Combined With Mass Conservation

    DEFF Research Database (Denmark)

    Morlighem, M.; Williams, C. N.; Rignot, E.

    2017-01-01

    Greenland's bed topography is a primary control on ice flow, grounding line migration, calving dynamics, and subglacial drainage. Moreover, fjord bathymetry regulates the penetration of warm Atlantic water (AW) that rapidly melts and undercuts Greenland's marine‐terminating glaciers. Here we...... present a new compilation of Greenland bed topography that assimilates seafloor bathymetry and ice thickness data through a mass conservation approach. A new 150 m horizontal resolution bed topography/bathymetric map of Greenland is constructed with seamless transitions at the ice/ocean interface...

  4. Nanoscale surface topographies for structural colors

    DEFF Research Database (Denmark)

    Clausen, Jeppe Sandvik

    The thesis describes and demonstrates the possibilities for utilization of structural colors in mass fabricated plastic products as replacement for or in combination with pigments and inks. The motivation is the possible advantages related to re-cycling and re-use of plastic by limiting the number......-polymer interface is suppressed. This improves the ability to see through a clear plastic in the presence of specular reflection. The tapered nanostructures are also utilized to enhance the chroma of pigmented polymers. Larger tapered structures fabricated in a similar manor are shown to work as color filters....... Through an experimental study is the color of the transmitted light linked directly to the random topography of the surface by use of diffraction theory. The color effects from periodic structures and how these might be employed to create bright colors are investigated. This is done both for opaque...

  5. Coupling between apical tension and basal adhesion allow epithelia to collectively sense and respond to substrate topography over long distances.

    Science.gov (United States)

    Broaders, Kyle E; Cerchiari, Alec E; Gartner, Zev J

    2015-12-01

    Epithelial sheets fold into complex topographies that contribute to their function in vivo. Cells can sense and respond to substrate topography in their immediate vicinity by modulating their interfacial mechanics, but the extent to which these mechanical properties contribute to their ability to sense substrate topography across length scales larger than a single cell has not been explored in detail. To study the relationship between the interfacial mechanics of single cells and their collective behavior as tissues, we grew cell-sheets on substrates engraved with surface features spanning macroscopic length-scales. We found that many epithelial cell-types sense and respond to substrate topography, even when it is locally nearly planar. Cells clear or detach from regions of local negative curvature, but not from regions with positive or no curvature. We investigated this phenomenon using a finite element model where substrate topography is coupled to epithelial response through a balance of tissue contractility and adhesive forces. The model correctly predicts the focal sites of cell-clearing and epithelial detachment. Furthermore, the model predicts that local tissue response to substrate curvature is a function of the surrounding topography of the substrate across long distances. Analysis of cell-cell and cell-substrate contact angles suggests a relationship between these single-cell interfacial properties, epithelial interfacial properties, and collective epithelial response to substrate topography. Finally, we show that contact angles change upon activation of oncogenes or inhibition of cell-contractility, and that these changes correlate with collective epithelial response. Our results demonstrate that in mechanically integrated epithelial sheets, cell contractility can be transmitted through multiple cells and focused by substrate topography to affect a behavioral response at distant sites.

  6. Relationship between Topography and Some Soil Properties

    Directory of Open Access Journals (Sweden)

    M. J. Pajand

    2016-09-01

    Full Text Available Introduction: Topography is an important and effective property affecting the soil quality. Some researchers demonstrated that degree and aspect of land slope may influence the particle size distribution and gravel. Slope degree affects the surface and subsurface run-off, drainage, soil temperature, stability of soil aggregates and soil erosion. This research was carried out to determine the spatial variation of soil properties in different slope degrees of northern and southern slopes in Khorasan Razavei province, Iran. Material and Methods: This study was performed in Sanganeh research station (longitude 60o 15ʹ60ʺ and latitude 36o 41ʹ 36ʺ, of north-eastern, Khorasan Razavi province of Iran. In order to study the effects of topography on some soil physical and chemical properties, a topo-sequence with the same slope length, parent materials and cover crops was selected. 30 soil samples (0-30 cm depth were collected from different slopes of less than 5, 5-15, 15-30, 30-50 and more than 50 percent of both southern and northern aspects. In this study, the soil particle size distribution (texture was measured by hydrometer method, organic carbon and calcium carbonate were determined by wet oxidation and titration with HCl 6 M, respectively and soil structural stability index, aggregates mean weight diameter and particles fractal dimension were calculated by related equations. Finally, the studied soil properties of 5 slopes (less than 5, 5-15, 15-30, 30-50, and more than 50% and 2 aspects (north and south with 3 replicates were compared by nested experimental design and Tuky test in JMP statistical software. Results and Discussion: The maximum and minimum clay contents as well as fractal dimension and organic carbon contents were found in less than 5% and more than 50% of south slopes, respectively. Clay content and fractal dimension in north aspect were also significantly (P

  7. Mars topography: bulk statistics and spectral scaling

    International Nuclear Information System (INIS)

    Nikora, V.; Goring, D.

    2004-01-01

    In this paper we present a systematic study of the Mars topography focusing on the statistical distributions and maps of the 5 deg.x 5 deg.cell-averaged mean elevations, standard deviations, skewness and kurtosis coefficients, and power spectra. Altogether, the obtained data suggest that at a 5 deg.x 5 deg.cell scale a large portion of the Martian surface may be reasonably considered as a Gaussian random field with a three-range spectrum consisting: (1) a high-energy low-wave-number range (∼0.003 -1 ) where the spectrum may deviate from a power law and attain a maximum; (2) scaling range 1 (∼0.03 -1 ) where the spectrum may be well approximated as S(k)∝k -β 1 ; and (3) scaling range 2 (∼(0.2-0.3) -1 ) where the spectrum may be also approximated as a power function but with a different exponent, i.e., S(k)∝k -β 2 . The most probable values for the exponents are β 1 =(2.2-2.4) and β 2 =3.8. The data show that the separation of these two scaling ranges most frequently occurs at L c ∼3.3 km. At a scale larger than the 5 deg.x 5 deg.cell scale the topography is highly intermittent with patchy spatial distributions of the key statistical moments. This patchiness is superimposed with systematic north-to-south trends in statistical properties, reflecting the crustal dichotomy of the planet and large-scale differences in the surface-forming processes

  8. Twin Positive Solutions of a Nonlinear m-Point Boundary Value Problem for Third-Order p-Laplacian Dynamic Equations on Time Scales

    Directory of Open Access Journals (Sweden)

    Wei Han

    2008-01-01

    Full Text Available Several existence theorems of twin positive solutions are established for a nonlinear m-point boundary value problem of third-order p-Laplacian dynamic equations on time scales by using a fixed point theorem. We present two theorems and four corollaries which generalize the results of related literature. As an application, an example to demonstrate our results is given. The obtained conditions are different from some known results.

  9. Offside Decisions by Expert Assistant Referees in Association Football: Perception and Recall of Spatial Positions in Complex Dynamic Events

    Science.gov (United States)

    Gilis, Bart; Helsen, Werner; Catteeuw, Peter; Wagemans, Johan

    2008-01-01

    This study investigated the offside decision-making process in association football. The first aim was to capture the specific offside decision-making skills in complex dynamic events. Second, we analyzed the type of errors to investigate the factors leading to incorrect decisions. Federation Internationale de Football Association (FIFA; n = 29)…

  10. Measurement of the square measure of the pharynx and the positional diagnosis of airway obstruction during obstructive sleep apnea syndrome by dynamic MRI

    International Nuclear Information System (INIS)

    Ozuki, Taizo; Ohkubo, Yasuo; Abe, Kimihiko

    2000-01-01

    The purpose of this study was to apply dynamic MRI for the positional diagnosis of airway obstruction during snoring and sleep apnea and to compare the apnea hypopnea index (AHI) and the square measure of the pharynx obtained before and after laser-assisted uvula-palate-pharyngoplasty (LAUP). From December 1997 to October 1998, dynamic MRI and overnight monitoring were performed at the hospital of Tokyo Medical University on 42 patients who complained of snoring and symptoms related to sleep apnea syndrome (SAS). Of the 42 patients, four exhibited collapse at the position of the soft palate (soft palate type) as diagnosed by dynamic MRI, and four exhibited collapse at the position of the soft palate as well as the tongue (complex type). LAUP was performed on these eight patients with obstructive SAS (OSAS). After LAUP, the AHI of these eight patients with OSAS decreased significantly (p<0.05). The square measure of the pharynx of these eight patients was increased (p<0.01). The AHI of all four patients with soft-palate obstruction decreased, and the square measure of the pharynx of three of these four patients increased. The AHI of three of four patients with the complex type decreased, while the square measure of the pharynx of two of these four patients increased. (author)

  11. Measurement of the square measure of the pharynx and the positional diagnosis of airway obstruction during obstructive sleep apnea syndrome by dynamic MRI

    Energy Technology Data Exchange (ETDEWEB)

    Ozuki, Taizo; Ohkubo, Yasuo; Abe, Kimihiko [Tokyo Medical Coll. (Japan)

    2000-11-01

    The purpose of this study was to apply dynamic MRI for the positional diagnosis of airway obstruction during snoring and sleep apnea and to compare the apnea hypopnea index (AHI) and the square measure of the pharynx obtained before and after laser-assisted uvula-palate-pharyngoplasty (LAUP). From December 1997 to October 1998, dynamic MRI and overnight monitoring were performed at the hospital of Tokyo Medical University on 42 patients who complained of snoring and symptoms related to sleep apnea syndrome (SAS). Of the 42 patients, four exhibited collapse at the position of the soft palate (soft palate type) as diagnosed by dynamic MRI, and four exhibited collapse at the position of the soft palate as well as the tongue (complex type). LAUP was performed on these eight patients with obstructive SAS (OSAS). After LAUP, the AHI of these eight patients with OSAS decreased significantly (p<0.05). The square measure of the pharynx of these eight patients was increased (p<0.01). The AHI of all four patients with soft-palate obstruction decreased, and the square measure of the pharynx of three of these four patients increased. The AHI of three of four patients with the complex type decreased, while the square measure of the pharynx of two of these four patients increased. (author)

  12. Modelling wetting and drying effects over complex topography

    Science.gov (United States)

    Tchamen, G. W.; Kahawita, R. A.

    1998-06-01

    The numerical simulation of free surface flows that alternately flood and dry out over complex topography is a formidable task. The model equation set generally used for this purpose is the two-dimensional (2D) shallow water wave model (SWWM). Simplified forms of this system such as the zero inertia model (ZIM) can accommodate specific situations like slowly evolving floods over gentle slopes. Classical numerical techniques, such as finite differences (FD) and finite elements (FE), have been used for their integration over the last 20-30 years. Most of these schemes experience some kind of instability and usually fail when some particular domain under specific flow conditions is treated. The numerical instability generally manifests itself in the form of an unphysical negative depth that subsequently causes a run-time error at the computation of the celerity and/or the friction slope. The origins of this behaviour are diverse and may be generally attributed to:1. The use of a scheme that is inappropriate for such complex flow conditions (mixed regimes).2. Improper treatment of a friction source term or a large local curvature in topography.3. Mishandling of a cell that is partially wet/dry.In this paper, a tentative attempt has been made to gain a better understanding of the genesis of the instabilities, their implications and the limits to the proposed solutions. Frequently, the enforcement of robustness is made at the expense of accuracy. The need for a positive scheme, that is, a scheme that always predicts positive depths when run within the constraints of some practical stability limits, is fundamental. It is shown here how a carefully chosen scheme (in this case, an adaptation of the solver to the SWWM) can preserve positive values of water depth under both explicit and implicit time integration, high velocities and complex topography that may include dry areas. However, the treatment of the source terms: friction, Coriolis and particularly the bathymetry

  13. Measurement noise of a point autofocus surface topography instrument

    DEFF Research Database (Denmark)

    Feng, Xiaobing; Quagliotti, Danilo; Maculotti, Giacomo

    Optical instruments for areal topography measurement can be especially sensitive to noise when scanning is required. Such noise has different sources, including those internally generated and external sources from the environment.......Optical instruments for areal topography measurement can be especially sensitive to noise when scanning is required. Such noise has different sources, including those internally generated and external sources from the environment....

  14. Ekman effects in a rotating flow over bottom topography

    NARCIS (Netherlands)

    Zavala Sansón, L.; Heijst, van G.J.F.

    2002-01-01

    This paper presents a general two-dimensional model for rotating barotropic flows over topography. The model incorporates in a vorticity–stream function formulation both inviscid topography effects, associated with stretching and squeezing of fluid columns enforced by their motion over variable

  15. Investigating Flow Features Near Abrupt Topography in the Mariana Basin

    Science.gov (United States)

    2015-09-30

    1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Investigating Flow Features Near Abrupt Topography in...waves generated by flow over topography and mesoscale eddies generated by flow past islands. Having identified the prime locations in the region for such

  16. Relating Cenozoic North Sea sediments to topography in southern Norway:

    DEFF Research Database (Denmark)

    Anell, Ingrid Anna Margareta; Thybo, Hans; Stratford, Wanda Rose

    2010-01-01

    the Shetland platform continued throughout the Cenozoic while supply from southern Norway increased markedly around the Eocene–Oligocene, coeval with the greenhouse–icehouse transition. Mass balance calculations of sediment and eroded rock volumes suggest that while some topography along the western margin...... that Plio-Pleistocene erosion over-deepened a pre-existing topography....

  17. Cokriging surface elevation and seismic refraction data for bedrock topography

    International Nuclear Information System (INIS)

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

    1992-01-01

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

  18. Clinical Validation of Point-Source Corneal Topography in Keratoplasty

    NARCIS (Netherlands)

    Vrijling, A C L; Braaf, B.; Snellenburg, J.J.; de Lange, F.; Zaal, M.J.W.; van der Heijde, G.L.; Sicam, V.A.D.P.

    2011-01-01

    Purpose. To validate the clinical performance of point-source corneal topography (PCT) in postpenetrating keratoplasty (PKP) eyes and to compare it with conventional Placido-based topography. Methods. Corneal elevation maps of the anterior corneal surface were obtained from 20 post-PKP corneas using

  19. Diffusion processes in bombardment-induced surface topography

    International Nuclear Information System (INIS)

    Robinson, R.S.

    1984-01-01

    A treatment is given of the problem of surface diffusion processes occurring during surface topography development, whenever a surface is simultaneously seeded with impurities and ion bombarded. The development of controllable topography and the importance of surface diffusion parameters, which can be obtained during these studies, are also analyzed. 101 refs.; 7 figs.; 2 tabs

  20. Influence of the tip mass and position on the AFM cantilever dynamics: Coupling between bending, torsion and flexural modes

    Energy Technology Data Exchange (ETDEWEB)

    Mokhtari-Nezhad, F. [Department of Mechanical Engineering, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Saidi, A.R., E-mail: saidi@mail.uk.ac.ir [Department of Mechanical Engineering, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Ziaei-Rad, S. [Department of Mechanical Engineering, Isfahan University of Technology (IUT), Isfahan 84156-83111 (Iran, Islamic Republic of)

    2009-08-15

    The effects of the geometrical asymmetric related to tip position as a concentrated mass, on the sensitivity of all three vibration modes, lateral excitation (LE), torsional resonance (TR) and vertical excitation (VE), of an atomic force microscopy (AFM) microcantilever have been analyzed. The effects of the tip mass and its position are studied to report the novel results to estimating the vibration behavior of AFM such as resonance frequency and amplitude of the microcantilever. In this way, to achieve more accurate results, the coupled motion in all three modes is considered. In particular, it is investigated that performing the coupled motion in analysis of AFM microcantilever is almost necessary. It is shown that the tip mass and its position have significant effects on vibrational responses. The results show that considering the tip mass decreases the resonance frequencies particularly on high-order modes. However, dislocating of tip position has an inverse effect that causes an increase in the resonance frequencies. In addition, it has been shown that the amplitude of the AFM microcantilever is affected by the influences of tip and its position. These effects are caused by the interaction between flexural and torsional motion due to the moment of inertia of the tip mass.

  1. Influence of the tip mass and position on the AFM cantilever dynamics: Coupling between bending, torsion and flexural modes

    International Nuclear Information System (INIS)

    Mokhtari-Nezhad, F.; Saidi, A.R.; Ziaei-Rad, S.

    2009-01-01

    The effects of the geometrical asymmetric related to tip position as a concentrated mass, on the sensitivity of all three vibration modes, lateral excitation (LE), torsional resonance (TR) and vertical excitation (VE), of an atomic force microscopy (AFM) microcantilever have been analyzed. The effects of the tip mass and its position are studied to report the novel results to estimating the vibration behavior of AFM such as resonance frequency and amplitude of the microcantilever. In this way, to achieve more accurate results, the coupled motion in all three modes is considered. In particular, it is investigated that performing the coupled motion in analysis of AFM microcantilever is almost necessary. It is shown that the tip mass and its position have significant effects on vibrational responses. The results show that considering the tip mass decreases the resonance frequencies particularly on high-order modes. However, dislocating of tip position has an inverse effect that causes an increase in the resonance frequencies. In addition, it has been shown that the amplitude of the AFM microcantilever is affected by the influences of tip and its position. These effects are caused by the interaction between flexural and torsional motion due to the moment of inertia of the tip mass.

  2. A gain-field encoding of limb position and velocity in the internal model of arm dynamics.

    Directory of Open Access Journals (Sweden)

    Eun Jung Hwang

    2003-11-01

    Full Text Available Adaptability of reaching movements depends on a computation in the brain that transforms sensory cues, such as those that indicate the position and velocity of the arm, into motor commands. Theoretical consideration shows that the encoding properties of neural elements implementing this transformation dictate how errors should generalize from one limb position and velocity to another. To estimate how sensory cues are encoded by these neural elements, we designed experiments that quantified spatial generalization in environments where forces depended on both position and velocity of the limb. The patterns of error generalization suggest that the neural elements that compute the transformation encode limb position and velocity in intrinsic coordinates via a gain-field; i.e., the elements have directionally dependent tuning that is modulated monotonically with limb position. The gain-field encoding makes the counterintuitive prediction of hypergeneralization: there should be growing extrapolation beyond the trained workspace. Furthermore, nonmonotonic force patterns should be more difficult to learn than monotonic ones. We confirmed these predictions experimentally.

  3. Lithography-Free Fabrication of Reconfigurable Substrate Topography For Contact Guidance

    Science.gov (United States)

    Pholpabu, Pitirat; Kustra, Stephen; Wu, Haosheng; Balasubramanian, Aditya; Bettinger, Christopher J.

    2014-01-01

    Mammalian cells detect and respond to topographical cues presented in natural and synthetic biomaterials both in vivo and in vitro. Micro- and nano-structures influence the adhesion, morphology, proliferation, migration, and differentiation of many phenotypes. Although the mechanisms that underpin cell-topography interactions remain elusive, synthetic substrates with well-defined micro- and nano-structures are important tools to elucidate the origin of these responses. Substrates with reconfigurable topography are desirable because programmable cues can be harmonized with dynamic cellular responses. Here we present a lithography-free fabrication technique that can reversibly present topographical cues using an actuation mechanism that minimizes the confounding effects of applied stimuli. This method utilizes strain-induced buckling instabilities in bi-layer substrate materials with rigid uniform silicon oxide membranes that are thermally deposited on elastomeric substrates. The resulting surfaces are capable of reversible of substrates between three distinct states: flat substrates (A = 1.53 ± 0.55 nm, Rms = 0.317 ± 0.048 nm); parallel wavy grating arrays (A|| = 483.6 ± 7.8 nm and λ|| = 4.78 ± 0.16 μm); perpendicular wavy grating arrays (A⊥ = 429.3 ± 5.8 nm; λ⊥ = 4.95 ± 0.36 μm). The cytoskeleton dynamics of 3T3 fibroblasts in response to these surfaces was measured using optical microscopy. Fibroblasts cultured on dynamic substrates that are switched from flat to topographic features (FLAT-WAVY) exhibit a robust and rapid change in gross morphology as measured by a reduction in circularity from 0.30 ± 0.13 to 0.15 ± 0.08 after 5 min. Conversely, dynamic substrate sequences of FLAT-WAVY-FLAT do not significantly alter the gross steady-state morphology. Taken together, substrates that present topographic structures reversibly can elucidate dynamic aspects of cell-topography interactions. PMID:25468368

  4. High temperature X-ray topography on silicon and gallium arsenide

    International Nuclear Information System (INIS)

    Krueger, H.E.

    1976-01-01

    Beginning with a review of the different theories of X-ray scattering on perfect and deformed crystals, results of the dynamic theory relevant specifically for X-ray topography are presented. The reflected intensity recorded in a X-ray topogram is discussed as a function of the angle of incidence, crystal thickness and lateral distribution. These results, together with fundamental relations of the DT which are developed in the annex, give insight into the contrasts induced by defects. Using practical examples Borrmann contrast, contrast produced by point defect agglomerates and dislocations and the Burgers vector method are explained. Thus the whole spectrum of contrast phenomena observed in the experimental part of the paper is presented. The experimental results were achieved with a high-temperature X-ray topography facility constructed for this purpose. The facility is described. (orig./HPOE) [de

  5. The pure phases, the irreducible quantum fields, and dynamical symmetry breaking in Symanzik--Nelson positive quantum field theories

    International Nuclear Information System (INIS)

    Frohlich, J.

    1976-01-01

    We prove that a Symanzik--Nelson positive quantum field theory, i.e., a quantum field theory derived from a Euclidean field theory, has a unique decomposition into pure phases which preserves Symanzik--Nelson positivity and Poincare covariance. We derive useful sufficient conditions for the breakdown of an internal symmetry of such a theory in its pure phases, for the self-adjointness and nontrivially (in the sense of Borchers classes) of its quantum fields, and the existence of time-ordered and retarded products. All these general results are then applied to the P (phi) 2 and the phi 3 4 quantum field models

  6. Adaptive Topographies and Equilibrium Selection in an Evolutionary Game

    Science.gov (United States)

    Osinga, Hinke M.; Marshall, James A. R.

    2015-01-01

    It has long been known in the field of population genetics that adaptive topographies, in which population equilibria maximise mean population fitness for a trait regardless of its genetic bases, do not exist. Whether one chooses to model selection acting on a single locus or multiple loci does matter. In evolutionary game theory, analysis of a simple and general game involving distinct roles for the two players has shown that whether strategies are modelled using a single ‘locus’ or one ‘locus’ for each role, the stable population equilibria are unchanged and correspond to the fitness-maximising evolutionary stable strategies of the game. This is curious given the aforementioned population genetical results on the importance of the genetic bases of traits. Here we present a dynamical systems analysis of the game with roles detailing how, while the stable equilibria in this game are unchanged by the number of ‘loci’ modelled, equilibrium selection may differ under the two modelling approaches. PMID:25706762

  7. Dynamic maintenance of asymmetric meiotic spindle position through Arp2/3 complex-driven cytoplasmic streaming in mouse oocytes

    Science.gov (United States)

    Yi, Kexi; Unruh, Jay R.; Deng, Manqi; Slaughter, Brian D.; Rubinstein, Boris; Li, Rong

    2012-01-01

    Mature mammalian oocytes are poised for the completion of second polar body extrusion upon fertilization by positioning the metaphase spindle in close proximity to an actomyosin-rich cortical cap. Loss of this spindle position asymmetry is often associated with poor oocyte quality and infertility 1–3. Here, we report a novel role for the Arp2/3 actin nucleation complex in the maintenance of asymmetric spindle position in mature mouse oocytes. The Arp2/3 complex localizes to the cortical cap in a Ran GTPase-dependent manner and accounts for the nucleation of the majority of actin filaments in both the cortical cap and a cytoplasmic actin network. Inhibition of Arp2/3 complex activity or localization leads to rapid dissociation of the spindle from the cortex. High resolution live imaging and spatiotemporal image correlation spectroscopy (STICS) analysis reveal that in normal oocytes actin filaments flow continuously away from the Arp2/3-rich cortex, generating a cytoplamic streaming that results in a net pushing force on the spindle toward the actomyosin cap. Arp2/3 inhibition not only diminishes this actin flow and cytoplamic streaming but also enables a reverse streaming driven by myosin-II-based cortical contraction, leading to spindle movement away from the cortex. We conclude that the Arp2/3 complex maintains asymmetric meiotic spindle position by generating an actin polymerization-driven cytoplamic streaming and by suppressing a counteracting force from myosin-II-based contractility. PMID:21874009

  8. Historical topography of the Tsarev settlement site

    Directory of Open Access Journals (Sweden)

    Glukhov Aleksandr A.

    2014-06-01

    Full Text Available The topography of the Tsarev settlement site, one of major Golden Horde monuments in the Lower Volga region, is analyzed. The first descriptions of the settlement refer to the second half of the 18th century, while the initial large-scale excavations on the monument were conducted in the mid-19th century. By that time, the scientific community had adhered to the opinion that the ruins of Sarai (the city mainly associated with the Tsarev settlement site would stretch to a great distance from the Akhtuba river-head to Kolobovka village. The results of archaeological research of the 20th – early 21st century make it possible to challenge this view. To date, it is an established fact that the size of the actual urban area had constituted 5 x 2.2–2.3 km. The southern part of the city was occupied by the estates of the nobility, the central and northern parts were represented by trade and artisan quarters. Around the city, there were suburban cemeteries, including brick mausoleums (the ruins of which could be mistaken for the remains of dwellings in the 19th century, as well as the areas of irrigated agriculture.

  9. Scleral topography analysed by optical coherence tomography.

    Science.gov (United States)

    Bandlitz, Stefan; Bäumer, Joachim; Conrad, Uwe; Wolffsohn, James

    2017-08-01

    A detailed evaluation of the corneo-scleral-profile (CSP) is of particular relevance in soft and scleral lenses fitting. The aim of this study was to use optical coherence tomography (OCT) to analyse the profile of the limbal sclera and to evaluate the relationship between central corneal radii, corneal eccentricity and scleral radii. Using OCT (Optos OCT/SLO; Dunfermline, Scotland, UK) the limbal scleral radii (SR) of 30 subjects (11M, 19F; mean age 23.8±2.0SD years) were measured in eight meridians 45° apart. Central corneal radii (CR) and corneal eccentricity (CE) were evaluated using the Oculus Keratograph 4 (Oculus, Wetzlar, Germany). Differences between SR in the meridians and the associations between SR and corneal topography were assessed. Median SR measured along 45° (58.0; interquartile range, 46.8-84.8mm) was significantly (ptopography and may provide additional data useful in fitting soft and scleral contact lenses. Copyright © 2017 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  10. X-ray topography of uranium alloys

    International Nuclear Information System (INIS)

    Le Naour, L.

    1984-01-01

    The limitations of x-ray topography methods are due to the variety of structures studied and to the variation of the amplitude of the scattering of incident beams. It is difficult to evaluate the aberrations and the imperfections of the material studied. Interpretation of the x-ray images will often be delicate and that is aggravated by the complexity of the diffraction spectrum of uranium. This negative aspect is compensated for by the advantage that chemical or electrochemical preparations of the alloy surface, along with alterations that can take place and the lack of trueness are avoided. Precise and very reproducible numerical data can be derived from the patterns. The structure of alloys, at a given scale, is revealed and characterized by quantitative parameters such as size of grains or sub-grains, dispersion of their dimensions, mutual disorientations and the continuous or discontinuous nature of the latter. The results of this research, therefore, justify the use of methods inspired by the Berg-Barrett technique. These diffraction procedures constitute a useful means for investigating many elements of microstructure that closely govern the behavior under irradiation of the materials being examined

  11. Calibration of areal surface topography measuring instruments

    Science.gov (United States)

    Seewig, J.; Eifler, M.

    2017-06-01

    The ISO standards which are related to the calibration of areal surface topography measuring instruments are the ISO 25178-6xx series which defines the relevant metrological characteristics for the calibration of different measuring principles and the ISO 25178-7xx series which defines the actual calibration procedures. As the field of areal measurement is however not yet fully standardized, there are still open questions to be addressed which are subject to current research. Based on this, selected research results of the authors in this area are presented. This includes the design and fabrication of areal material measures. For this topic, two examples are presented with the direct laser writing of a stepless material measure for the calibration of the height axis which is based on the Abbott- Curve and the manufacturing of a Siemens star for the determination of the lateral resolution limit. Based on these results, as well a new definition for the resolution criterion, the small scale fidelity, which is still under discussion, is presented. Additionally, a software solution for automated calibration procedures is outlined.

  12. Wettability control by DLC coated nanowire topography

    Science.gov (United States)

    Li, Zihui; Meng, Fanhao; Liu, Xuanyong

    2011-04-01

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

  13. Light source for synchrotron radiation x-ray topography study at Beijing Synchrotron Radiation Laboratory (BSRL)

    International Nuclear Information System (INIS)

    Zhao Jiyong; Jiang Jianhua; Tian Yulian

    1992-01-01

    Characteristics of the synchrotron radiation source for X-ray topography study at Beijing Synchrotron Radiation Laboratory (BSRL) is described, local geometrical resolution of topographies is discussed, and the diffracting intensities of white beam topography is given

  14. Characterizing smoking topography of cannabis in heavy users

    Science.gov (United States)

    Stitzer, Maxine L.; Vandrey, Ryan

    2013-01-01

    Rationale Little is known about the smoking topography characteristics of heavy cannabis users. Such measures may be able to predict cannabis use-related outcomes and could be used to validate self-reported measures of cannabis use. Objectives The current study was conducted to measure cannabis smoking topography characteristics during periods of ad libitum use and to correlate topography assessments with measures of self-reported cannabis use, withdrawal and craving during abstinence, and cognitive task performance. Methods Participants (N=20) completed an inpatient study in which they alternated between periods of ad libitum cannabis use and abstinence. Measures of self-reported cannabis use, smoking topography, craving, withdrawal, and sleep measures were collected. Results Participants smoked with greater intensity (e.g., greater volume, longer duration) on initial cigarette puffs with a steady decline on subsequent puffs. Smoking characteristics were significantly correlated with severity of withdrawal, notably sleep quality and architecture, and craving during abstinence, suggesting dose-related effects of cannabis use on these outcomes. Smoking characteristics generally were not significantly associated with cognitive performance. Smoking topography measures were significantly correlated with self-reported measures of cannabis use, indicating validity of these assessments, but topography measures were more sensitive than self-report in predicting cannabis-related outcomes. Conclusions A dose–effect relationship between cannabis consumption and outcomes believed to be clinically important was observed. With additional research, smoking topography assessments may become a useful clinical tool. PMID:21922170

  15. The effect of skin surface topography and skin colouration cues on perception of male facial age, health and attractiveness.

    Science.gov (United States)

    Fink, B; Matts, P J; Brauckmann, C; Gundlach, S

    2018-04-01

    Previous studies investigating the effects of skin surface topography and colouration cues on the perception of female faces reported a differential weighting for the perception of skin topography and colour evenness, where topography was a stronger visual cue for the perception of age, whereas skin colour evenness was a stronger visual cue for the perception of health. We extend these findings in a study of the effect of skin surface topography and colour evenness cues on the perceptions of facial age, health and attractiveness in males. Facial images of six men (aged 40 to 70 years), selected for co-expression of lines/wrinkles and discolouration, were manipulated digitally to create eight stimuli, namely, separate removal of these two features (a) on the forehead, (b) in the periorbital area, (c) on the cheeks and (d) across the entire face. Omnibus (within-face) pairwise combinations, including the original (unmodified) face, were presented to a total of 240 male and female judges, who selected the face they considered younger, healthier and more attractive. Significant effects were detected for facial image choice, in response to skin feature manipulation. The combined removal of skin surface topography resulted in younger age perception compared with that seen with the removal of skin colouration cues, whereas the opposite pattern was found for health preference. No difference was detected for the perception of attractiveness. These perceptual effects were seen particularly on the forehead and cheeks. Removing skin topography cues (but not discolouration) in the periorbital area resulted in higher preferences for all three attributes. Skin surface topography and colouration cues affect the perception of age, health and attractiveness in men's faces. The combined removal of these features on the forehead, cheeks and in the periorbital area results in the most positive assessments. © 2018 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  16. UV laser micromachining of ceramic materials: formation of columnar topographies

    International Nuclear Information System (INIS)

    Oliveira, V.; Vilar, R.; Conde, O.

    2001-01-01

    Laser machining is increasingly appearing as an alternative for micromachining of ceramics. Using ceramic materials using excimer lasers can result in smooth surfaces or in the formation of cone-like or columnar topography. Potential applications of cone-shaped or columnar surface topography include, for example, light trapping in anti-reflection coatings and improvement of adhesion bonding between ceramic materials. In this communication results of a comparative study of surface topography change during micromachining of several ceramic materials with different ablation behaviors are reported. (orig.)

  17. PROSTATE CANCER TOPOGRAPHY AND PATTERNS OF LYMPH NODE METASTASIS

    Science.gov (United States)

    Tokuda, Yuji; Carlino, Lauren J.; Gopalan, Anuradha; Tickoo, Satish K.; Kaag, Matthew G.; Guillonneau, Bertrand; Eastham, James A.; Scher, Howard I.; Scardino, Peter T.; Reuter, Victor E.; Fine, Samson W.

    2012-01-01

    Pelvic lymph node (LN) metastasis is a well-recognized route of prostate cancer spread. However, the relationship between topography and pathologic features of primary prostatic cancers and patterns of pelvic LN metastasis has not been well studied. We reviewed original slides of radical prostatectomies and pelvic LN dissections from 125 patients with LN metastasis and recorded total # of LN excised / laterality of positive LN, as well as localization, staging parameters, lymphovascular invasion and tumor volume of primary tumors. LN Quantity and Distribution 14.6 (mean) and 13 (median) LN were resected. 76 (61%), 33 (26%) and 16 (13%) cases had 1, 2 and > 2 positive LN, while 58, 44 and 20 cases had LN metastasis on the right (R), left (L), and bilaterally. Pathologic Features 86% (108/125) and 37% (46/125) demonstrated extraprostatic extension and seminal vesicle invasion, while 64% showed lymphovascular invasion. Mean and median total tumor volume was 6.39 and 3.92 cc, with ≥ 50% and ≥ 90% Gleason patterns 4/5 in 105 (84%) and 73 (58%) cases, respectively. Correlation with Dominant Tumor Location Dominant lesions on RP: 50 R lobe, 44 L lobe, 31 bilateral. 15/50 (30%) R lobe and 18/44 (41%) L lobe dominant tumors had LN metastasis on the contralateral side. Only 4% (5/125) of cases were associated with anterior dominant tumors. 30–40% of LN metastases occur contralateral to the dominant tumor. LN metastasis is overwhelmingly associated with high grade, high stage and large volume disease. LN positivity is rarely associated with anterior dominant tumors. PMID:21107093

  18. Positive Feedback Regulation of Agonist-Stimulated Endothelial Ca2+ Dynamics by KCa3.1 Channels in Mouse Mesenteric Arteries

    DEFF Research Database (Denmark)

    Qian, Xun; Francis, Michael; Köhler, Ralf

    2014-01-01

    Intermediate and small conductance KCa channels IK1 (KCa3.1) and SK3 (KCa2.3) are primary targets of endothelial Ca(2+) signals in the arterial vasculature, and their ablation results in increased arterial tone and hypertension. Activation of IK1 channels by local Ca(2+) transients from internal ...... stores or plasma membrane channels promotes arterial hyperpolarization and vasodilation. Here, we assess arteries from genetically altered IK1 knockout mice (IK1(-/-)) to determine whether IK1 channels exert a positive feedback influence on endothelial Ca(2+) dynamics....

  19. The key role of topography in altering North Atlantic atmospheric circulation during the last glacial period

    Directory of Open Access Journals (Sweden)

    F. S. R. Pausata

    2011-10-01

    Full Text Available The Last Glacial Maximum (LGM; 21 000 yr before present was a period of low atmospheric greenhouse gas concentrations, when vast ice sheets covered large parts of North America and Europe. Paleoclimate reconstructions and modeling studies suggest that the atmospheric circulation was substantially altered compared to today, both in terms of its mean state and its variability. Here we present a suite of coupled model simulations designed to investigate both the separate and combined influences of the main LGM boundary condition changes (greenhouse gases, ice sheet topography and ice sheet albedo on the mean state and variability of the atmospheric circulation as represented by sea level pressure (SLP and 200-hPa zonal wind in the North Atlantic sector. We find that ice sheet topography accounts for most of the simulated changes during the LGM. Greenhouse gases and ice sheet albedo affect the SLP gradient in the North Atlantic, but the overall placement of high and low pressure centers is controlled by topography. Additional analysis shows that North Atlantic sea surface temperatures and sea ice edge position do not substantially influence the pattern of the climatological-mean SLP field, SLP variability or the position of the North Atlantic jet in the LGM.

  20. Upper-mantle velocity structure and its relation to topography across the Caledonides in Greenland and Norway

    DEFF Research Database (Denmark)

    Hejrani, Babak; Balling, N.; Jacobsen, B. H.

    2015-01-01

    This study investigates the upper-mantle P- and S-wave velocity structure as well as structure in the VP/VS ratio across the high topography areas of north Atlantic Caledonides, integrating data from a new East Greenland Caledonide Central Fjord Array (EGCFA) with results of recent studies...... strong upper-mantle velocity boundary under the East Greenland Caledonides. However, the contrast in the VP/VS ratio is not as clear at this location. A correlation study of topography versus upper-mantle velocity revealed positive correlation in southern Norway but negative or absent correlation...

  1. Geology of Saipan, Mariana Islands; Part 4, Submarine topography and shoal-water ecology

    Science.gov (United States)

    Cloud, Preston E.

    1959-01-01

    The topography of the sea floor within 10 miles of Saipan broadly resembles that of the land. Eastward, toward the Mariana trench, slopes are about 6°, without prominent benches or scarps. This is inferred to indicate easterly continuation of generally pyroclastic bedrock. The westward slope averages 2° to 3° and consists mainly of nearly flat benches and westfacing scarps. This is taken to imply westward continuation of a limestone bench-and-fault-scarp topography. Projection of known faults to sea and through Tinian, on the basis of topographic trends, suggests a pattern of west-dipping normal faults that parallel the strike of the Mariana ridge and affect the shape and position of islands at the crest of the ridge.

  2. Dynamic Method of Neutral Axis Position Determination and Damage Identification with Distributed Long-Gauge FBG Sensors.

    Science.gov (United States)

    Tang, Yongsheng; Ren, Zhongdao

    2017-02-20

    The neutral axis position (NAP) is a key parameter of a flexural member for structure design and safety evaluation. The accuracy of NAP measurement based on traditional methods does not satisfy the demands of structural performance assessment especially under live traffic loads. In this paper, a new method to determine NAP is developed by using modal macro-strain (MMS). In the proposed method, macro-strain is first measured with long-gauge Fiber Bragg Grating (FBG) sensors; then the MMS is generated from the measured macro-strain with Fourier transform; and finally the neutral axis position coefficient (NAPC) is determined from the MMS and the neutral axis depth is calculated with NAPC. To verify the effectiveness of the proposed method, some experiments on FE models, steel beam and reinforced concrete (RC) beam were conducted. From the results, the plane section was first verified with MMS of the first bending mode. Then the results confirmed the high accuracy and stability for assessing NAP. The results also proved that the NAPC was a good indicator of local damage. In summary, with the proposed method, accurate assessment of flexural structures can be facilitated.

  3. Dynamic Method of Neutral Axis Position Determination and Damage Identification with Distributed Long-Gauge FBG Sensors

    Directory of Open Access Journals (Sweden)

    Yongsheng Tang

    2017-02-01

    Full Text Available The neutral axis position (NAP is a key parameter of a flexural member for structure design and safety evaluation. The accuracy of NAP measurement based on traditional methods does not satisfy the demands of structural performance assessment especially under live traffic loads. In this paper, a new method to determine NAP is developed by using modal macro-strain (MMS. In the proposed method, macro-strain is first measured with long-gauge Fiber Bragg Grating (FBG sensors; then the MMS is generated from the measured macro-strain with Fourier transform; and finally the neutral axis position coefficient (NAPC is determined from the MMS and the neutral axis depth is calculated with NAPC. To verify the effectiveness of the proposed method, some experiments on FE models, steel beam and reinforced concrete (RC beam were conducted. From the results, the plane section was first verified with MMS of the first bending mode. Then the results confirmed the high accuracy and stability for assessing NAP. The results also proved that the NAPC was a good indicator of local damage. In summary, with the proposed method, accurate assessment of flexural structures can be facilitated.

  4. The Role of Membrane Curvature in Nanoscale Topography-Induced Intracellular Signaling.

    Science.gov (United States)

    Lou, Hsin-Ya; Zhao, Wenting; Zeng, Yongpeng; Cui, Bianxiao

    2018-05-15

    Over the past decade, there has been growing interest in developing biosensors and devices with nanoscale and vertical topography. Vertical nanostructures induce spontaneous cell engulfment, which enhances the cell-probe coupling efficiency and the sensitivity of biosensors. Although local membranes in contact with the nanostructures are found to be fully fluidic for lipid and membrane protein diffusions, cells appear to actively sense and respond to the surface topography presented by vertical nanostructures. For future development of biodevices, it is important to understand how cells interact with these nanostructures and how their presence modulates cellular function and activities. How cells recognize nanoscale surface topography has been an area of active research for two decades before the recent biosensor works. Extensive studies show that surface topographies in the range of tens to hundreds of nanometers can significantly affect cell functions, behaviors, and ultimately the cell fate. For example, titanium implants having rough surfaces are better for osteoblast attachment and host-implant integration than those with smooth surfaces. At the cellular level, nanoscale surface topography has been shown by a large number of studies to modulate cell attachment, activity, and differentiation. However, a mechanistic understanding of how cells interact and respond to nanoscale topographic features is still lacking. In this Account, we focus on some recent studies that support a new mechanism that local membrane curvature induced by nanoscale topography directly acts as a biochemical signal to induce intracellular signaling, which we refer to as the curvature hypothesis. The curvature hypothesis proposes that some intracellular proteins can recognize membrane curvatures of a certain range at the cell-to-material interface. These proteins then recruit and activate downstream components to modulate cell signaling and behavior. We discuss current technologies

  5. Doubly versus singly positively charged oxygen ions back-scattered from a silicon surface under dynamic O2+ bombardment

    International Nuclear Information System (INIS)

    Franzreb, Klaus; Williams, Peter; Loerincik, Jan; Sroubek, Zdenek

    2003-01-01

    Mass-resolved (and emission-charge-state-resolved) low-energy ion back-scattering during dynamic O 2 + bombardment of a silicon surface was applied in a Cameca IMS-3f secondary ion mass spectrometry (SIMS) instrument to determine the bombarding energy dependence of the ratio of back-scattered O 2+ versus O + . While the ratio of O 2+ versus O + drops significantly at reduced bombarding energies, O 2+ back-scattered from silicon was still detectable at an impact energy (in the lab frame) as low as about 1.6 keV per oxygen atom. Assuming neutralization prior to impact, O 2+ ion formation in an asymmetric 16 O→ 28 Si collision is expected to take place via 'collisional double ionization' (i.e. by promotion of two outer O 2p electrons) rather than by the production of an inner-shell (O 2s or O 1s) core hole followed by Auger-type de-excitation during or after ejection. A molecular orbital (MO) correlation diagram calculated for a binary 'head-on' O-Si collision supports this interpretation

  6. Topography and diffractometry station in synchrotron radiation beam of the VEPP-4 storage ring. Topography of garnets

    International Nuclear Information System (INIS)

    Kub, I.; Poltsarova, M.; Panchenko, V.E.

    1987-01-01

    Advantages of synchrotron radiation (SR) spectrum of the VEhPP-4 storage ring for X-ray topography and diffractometry are shown. The description of ''Topography and diffractometry'' station in SR dump station of the VEhPP storage ring is presented, peculiarities of X-ray topography method used are discussed. X-ray topographic images of gadolinium-gallium and manganese-germanium garnets taken on the VEhPP SR are given in comparison with conventional images taken using X-ray tubes and SR of the VEhPP-3 storage ring

  7. Traveltime computation and imaging from rugged topography in 3D TTI media

    Science.gov (United States)

    Liu, Shaoyong; Wang, Huazhong; Yang, Qinyong; Fang, Wubao

    2014-02-01

    Foothill areas with rugged topography 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 topography, a new dynamic 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 topography and take anisotropy into account to achieve better images.

  8. Traveltime computation and imaging from rugged topography in 3D TTI media

    International Nuclear Information System (INIS)

    Liu, Shaoyong; Wang, Huazhong; Yang, Qinyong; Fang, Wubao

    2014-01-01

    Foothill areas with rugged topography 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 topography, a new dynamic 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 topography and take anisotropy into account to achieve better images. (paper)

  9. Reproducibility of UAV-based earth topography reconstructions based on Structure-from-Motion algorithms

    Science.gov (United States)

    Clapuyt, Francois; Vanacker, Veerle; Van Oost, Kristof

    2016-05-01

    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 dynamic natural environments. This methodology is particularly suitable for repeated topographic surveys in remote or poorly accessible areas. However, temporal analysis of landform topography 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 topography 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 topography 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.

  10. Effect of Hydrofluoric Acid Etching Time on Titanium Topography, Chemistry, Wettability, and Cell Adhesion.

    Directory of Open Access Journals (Sweden)

    R Zahran

    Full Text Available Titanium implant surface etching has proven an effective method to enhance cell attachment. Despite the frequent use of hydrofluoric (HF acid, many questions remain unresolved, including the optimal etching time and its effect on surface and biological properties. The objective of this study was to investigate the effect of HF acid etching time on Ti topography, surface chemistry, wettability, and cell adhesion. These data are useful to design improved acid treatment and obtain an improved cell response. The surface topography, chemistry, dynamic wetting, and cell adhesiveness of polished Ti surfaces were evaluated after treatment with HF acid solution for 0, 2; 3, 5, 7, or 10 min, revealing a time-dependent effect of HF acid on their topography, chemistry, and wetting. Roughness and wetting increased with longer etching time except at 10 min, when roughness increased but wetness decreased. Skewness became negative after etching and kurtosis tended to 3 with longer etching time. Highest cell adhesion was achieved after 5-7 min of etching time. Wetting and cell adhesion were reduced on the highly rough surfaces obtained after 10-min etching time.

  11. Effects of design parameters and puff topography on heating coil temperature and mainstream aerosols in electronic cigarettes

    Science.gov (United States)

    Zhao, Tongke; Shu, Shi; Guo, Qiuju; Zhu, Yifang

    2016-06-01

    Emissions from electronic cigarettes (ECs) may contribute to both indoor and outdoor air pollution and the number of users is increasing rapidly. ECs operate based on the evaporation of e-liquid by a high-temperature heating coil. Both puff topography and design parameters can affect this evaporation process. In this study, both mainstream aerosols and heating coil temperature were measured concurrently to study the effects of design parameters and puff topography. The heating coil temperatures and mainstream aerosols varied over a wide range across different brands and within same brand. The peak heating coil temperature and the count median diameter (CMD) of EC aerosols increased with a longer puff duration and a lower puff flow rate. The particle number concentration was positively associated with the puff duration and puff flow rate. These results provide a better understanding of how EC emissions are affected by design parameters and puff topography and emphasize the urgent need to better regulate EC products.

  12. Topography measurements for determining the decay factors in surface replication

    International Nuclear Information System (INIS)

    Song, J; Zheng, A; Vorburger, T V; Rubert, P

    2008-01-01

    The electro-forming technique is used at National Institute of Standards and Technology (NIST) for the production of standard reference material (SRM) 2461 standard casings to support nationwide ballistics measurement traceability and measurement quality control in the US. In order to ensure that the SRM casings are produced with virtually the same surface topography, it is necessary to test the decay factors of the replication process. Twenty-six replica casings are replicated from the same master casing for the decay factor tests. The NIST topography measurement system is used for measurements and correlations of surface topography. The topography decays are quantified by the cross-correlation function maximum CCF max . Based on the test, it is expected that 256 SRM casings can be replicated from the same master with CCF max values higher than 95%

  13. Silk Film Topography Directs Collective Epithelial Cell Migration

    Science.gov (United States)

    Rosenblatt, Mark I.

    2012-01-01

    The following study provides new insight into how surface topography dictates directed collective epithelial cell sheet growth through the guidance of individual cell movement. Collective cell behavior of migrating human corneal limbal-epithelial cell sheets were studied on highly biocompatible flat and micro-patterned silk film surfaces. The silk film edge topography guided the migratory direction of individual cells making up the collective epithelial sheet, which resulted in a 75% increase in total culture elongation. This was due to a 3-fold decrease in cell sheet migration rate efficiency for movement perpendicular to the topography edge. Individual cell migration direction is preferred in the parallel approach to the edge topography where localization of cytoskeletal proteins to the topography’s edge region is reduced, which results in the directed growth of the collective epithelial sheet. Findings indicate customized biomaterial surfaces may be created to direct both the migration rate and direction of tissue epithelialization. PMID:23185573

  14. Influence of local topography on precision irrigation management

    Science.gov (United States)

    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 topography, both in rain-fed and irrigated environments. Utilizing ...

  15. Influence of surface topography on the sputtering yields of silver

    International Nuclear Information System (INIS)

    Pan Jisheng; Wang Zhenxia; Tao Zhenlan; Zhang Jiping

    1992-01-01

    The sputtering yields of silver have been measured as a function of the fluence of incident Ar + ions (27 keV) using the collector technique and RBS analysis. The irradiated surface was examined by scanning electron microscopy (SEM). It is shown that the sputtering yields of surfaces with topography are enhanced relative to smooth surfaces of silver, but the extent of the enhancement depends on the irradiation dose. The experimental results can be explained assuming that the surface topography and sputtering yield are a function of incident angle. It is obvious that the surface topography is an important factor to influence the sputtering yield. The term ''apparent sputtering yield'' has specifically been used when referring to the experimental sputtering yield of a surface with topography, to emphasize the difference with a smooth surface. (orig.)

  16. Mandibular molar crown-topography, a biological predisposing ...

    African Journals Online (AJOL)

    Mandibular molar crown-topography, a biological predisposing factor to development of caries – a post-mortem analysis of 2500 extracted lower permanent molars at the dental centre, University of Benin teaching hospital.

  17. Measurement of Angle Kappa Using Ultrasound Biomicroscopy and Corneal Topography.

    Science.gov (United States)

    Yeo, Joon Hyung; Moon, Nam Ju; Lee, Jeong Kyu

    2017-06-01

    To introduce a new convenient and accurate method to measure the angle kappa using ultrasound biomicroscopy (UBM) and corneal topography. Data from 42 eyes (13 males and 29 females) were analyzed in this study. The angle kappa was measured using Orbscan II and calculated with UBM and corneal topography. The angle kappa of the dominant eye was compared with measurements by Orbscan II. The mean patient age was 36.4 ± 13.8 years. The average angle kappa measured by Orbscan II was 3.98° ± 1.12°, while the average angle kappa calculated with UBM and corneal topography was 3.19° ± 1.15°. The difference in angle kappa measured by the two methods was statistically significant (p topography to calculate the angle kappa. This method is convenient to use and allows for measurement of the angle kappa without an expensive device. © 2017 The Korean Ophthalmological Society

  18. Nano-topography Enhances Communication in Neural Cells Networks

    KAUST Repository

    Onesto, V.; Cancedda, L.; Coluccio, M. L.; Nanni, M.; Pesce, M.; Malara, N.; Cesarelli, M.; Di Fabrizio, Enzo M.; Amato, F.; Gentile, F.

    2017-01-01

    Neural cells are the smallest building blocks of the central and peripheral nervous systems. Information in neural networks and cell-substrate interactions have been heretofore studied separately. Understanding whether surface nano-topography can

  19. Dynamics

    CERN Document Server

    Goodman, Lawrence E

    2001-01-01

    Beginning text presents complete theoretical treatment of mechanical model systems and deals with technological applications. Topics include introduction to calculus of vectors, particle motion, dynamics of particle systems and plane rigid bodies, technical applications in plane motions, theory of mechanical vibrations, and more. Exercises and answers appear in each chapter.

  20. Hidden spondylolisthesis: unrecognized cause of low back pain? Prospective study about the use of dynamic projections in standing and recumbent position for the individuation of lumbar instability

    International Nuclear Information System (INIS)

    Landi, Alessandro; Gregori, Fabrizio; Marotta, Nicola; Donnarumma, Pasquale; Delfini, Roberto

    2015-01-01

    Dynamic X-rays (DXR) are widely recognized as an effective method to detect lumbar instability (LI). They are usually performed with the patient in standing position (SDXR). In our opinion, standing position inhibits micromovements of the lumbar segment interested by the listhesis, thanks to paravertebral muscles antalgic contraction and augmented tone. We aim to demonstrate that DXR in recumbent position (RDXR), reducing the action of paravertebral muscles, can discover hypermovements not evidenced in SDXR. Between January 2011 and January 2013, we studied 200 consecutive patients with lumbar degenerative disease with MRI, SDXR, and RDXR. We aimed to find a correlation between low back or radicular pain and the presence of a spondylolisthesis not showed by the SDXR, but showed by the RDXR. We analysed 200 patients: of the 133 not pathologic in SDXR, 43 patients (32.3 %) showed an hypermovement in RDXR (p = 0.0001) without any significant correlation between hidden listhesis and age, sex, or level involved. The aim of our study is to determine whether in patients with lumbalgy without evidence of listhesis in SDXR, pain can be attributed to a faccettal syndrome or to a spondylolisthesis. Consequence of pain is augmented muscular tone of the paravertebral musculature, particularly in standing position. Augmented muscular tone tries to inhibit the pain generator, attempting to limit the slippage of the involved segment. In patients examined in RDXR, the tone of paravertebral musculature is reduced, showing the hidden spondylolisthesis. (orig.)

  1. Hidden spondylolisthesis: unrecognized cause of low back pain? Prospective study about the use of dynamic projections in standing and recumbent position for the individuation of lumbar instability

    Energy Technology Data Exchange (ETDEWEB)

    Landi, Alessandro; Gregori, Fabrizio; Marotta, Nicola; Donnarumma, Pasquale; Delfini, Roberto [University of Rome - Policlinico Umberto I, Department of Neurology and Psychiatry, Division of Neurosurgery, Rome (Italy)

    2015-03-26

    Dynamic X-rays (DXR) are widely recognized as an effective method to detect lumbar instability (LI). They are usually performed with the patient in standing position (SDXR). In our opinion, standing position inhibits micromovements of the lumbar segment interested by the listhesis, thanks to paravertebral muscles antalgic contraction and augmented tone. We aim to demonstrate that DXR in recumbent position (RDXR), reducing the action of paravertebral muscles, can discover hypermovements not evidenced in SDXR. Between January 2011 and January 2013, we studied 200 consecutive patients with lumbar degenerative disease with MRI, SDXR, and RDXR. We aimed to find a correlation between low back or radicular pain and the presence of a spondylolisthesis not showed by the SDXR, but showed by the RDXR. We analysed 200 patients: of the 133 not pathologic in SDXR, 43 patients (32.3 %) showed an hypermovement in RDXR (p = 0.0001) without any significant correlation between hidden listhesis and age, sex, or level involved. The aim of our study is to determine whether in patients with lumbalgy without evidence of listhesis in SDXR, pain can be attributed to a faccettal syndrome or to a spondylolisthesis. Consequence of pain is augmented muscular tone of the paravertebral musculature, particularly in standing position. Augmented muscular tone tries to inhibit the pain generator, attempting to limit the slippage of the involved segment. In patients examined in RDXR, the tone of paravertebral musculature is reduced, showing the hidden spondylolisthesis. (orig.)

  2. Reformation and utilization of complicated topography for a uranium mill

    International Nuclear Information System (INIS)

    Liu Taoan; Zhou Xinghuo; Lv Junwen

    2004-01-01

    It is successful for how to reform and utilized complicated topography in the design of general plan and transport for technological reformation of a uranium mill. The unfavorable factors of complicated topography are turned into favorable ones. The general plan is designed compactly and the land is economized. The transport is designed simply and directly. the leaching liquid flows by gravity so that the power is economical

  3. Influence of surface topography on elastically backscattered electrons

    International Nuclear Information System (INIS)

    Ding, X; Da, B; Gong, J B; Ding, Z J; Mao, S F

    2014-01-01

    A Monte Carlo simulation, taking into account of the detailed surface roughness of a realistic solid sample, has been performed to study the surface topography influence on elastic peak intensity. To describe quantitatively the surface topography effect, here we introduce surface roughness parameter (SRP) according to the ratio of elastic peak intensities between a rough surface and an ideal planar surface. Simulation results for Al sample have shown that SRP varies with surface roughness particularly at large incidence/emission angles

  4. The development of surface topography by heavy ion sputtering

    International Nuclear Information System (INIS)

    Whitton, J.L.; Carter, G.

    1981-01-01

    The results of a detailed, systematic investigation of the development of energetic argon ion bombardment induced surface features on polycrystal and single crystal copper are presented. It is shown that the crystal structure itself is the dominant factor deciding the final form of surface topography. The earlier proposed ''necessary conditions'' for development of surface topography, viz. surface impurity, asperities, growth, surface migration and redeposition are shown to be unimportant under the clean conditions of the experiments. (Auth.)

  5. Topography-modified refraction (TMR): adjustment of treated cylinder amount and axis to the topography versus standard clinical refraction in myopic topography-guided LASIK.

    Science.gov (United States)

    Kanellopoulos, Anastasios John

    2016-01-01

    To evaluate the safety, efficacy, and contralateral eye comparison of topography-guided myopic LASIK with two different refraction treatment strategies. Private clinical ophthalmology practice. A total of 100 eyes (50 patients) in consecutive cases of myopic topography-guided LASIK procedures with the same refractive platform (FS200 femtosecond and EX500 excimer lasers) were randomized for treatment as follows: one eye with the standard clinical refraction (group A) and the contralateral eye with the topographic astigmatic power and axis (topography-modified treatment refraction; group B). All cases were evaluated pre- and post-operatively for the following parameters: refractive error, best corrected distance visual acuity (CDVA), uncorrected distance visual acuity (UDVA), topography (Placido-disk based) and tomography (Scheimpflug-image based), wavefront analysis, pupillometry, and contrast sensitivity. Follow-up visits were conducted for at least 12 months. Mean refractive error was -5.5 D of myopia and -1.75 D of astigmatism. In group A versus group B, respectively, the average UDVA improved from 20/200 to 20/20 versus 20/16; post-operative CDVA was 20/20 and 20/13.5; 1 line of vision gained was 27.8% and 55.6%; and 2 lines of vision gained was 5.6% and 11.1%. In group A, 27.8% of eyes had over -0.50 diopters of residual refractive astigmatism, in comparison to 11.7% in group B ( P Topography-modified refraction (TMR): topographic adjustment of the amount and axis of astigmatism treated, when different from the clinical refraction, may offer superior outcomes in topography-guided myopic LASIK. These findings may change the current clinical paradigm of the optimal subjective refraction utilized in laser vision correction.

  6. Relationship of Aphasia and Topography of Cerebrovascular Territories

    Directory of Open Access Journals (Sweden)

    K. Ghandehari

    2004-10-01

    Full Text Available Aphasia is a common manifestation of stroke and evaluation of relationships of aphasia and brain topography could lead to better understanding of cognitive neurophysiology.Consecutive 100 stroke patients with aphasia admitted in Valie Asr hospital, Khorasan in 2003 enrulled in this prospective study. Diagnosis of stroke and aphasia was made by a neurolosist and topography of involved cerebrovascular territories confirmed by topographic maps of brain in CT scan. Global, Broca and Wernicke subtypes of aphasia constituted 52%, 40% and 6% of the cases respectively. Based on the usual nourishment of Broca and Wernicke areas by anterior and posterior cortical branches of the middle cerebral artery, 79% of Global, 47% of Broca and 50% of Wernicke aphasias had a compatible infarct topography. Other cases had no congruent infarct topography with involved linguistic area of their brain. Specific cerebrovascular topography for subtypes of aphasia in stroke patients was not found. The effects of cerebrovascular lesions on linguistic functions are not predictable by their topography in CT scan.

  7. Cognitive “Boy stories”: urban folklore and urban topographies

    Directory of Open Access Journals (Sweden)

    Bojan Žikić

    2016-02-01

    Full Text Available The culturally cognitive perception of Belgrade’s topographies is considered through its deployment, symbolic use and narrative foundation. As the explanatory material-one football-media incident, the use of certain areas of the city in a spectacleceremonial manner, knowledge and lore of certain elements of the Belgrade topographies and the organization of «the football Belgrade»-were considered. The attitude is taken that the topography of a city is a multifaceted cultural constituent, whose structure of particular meaning, as a part of cultural communication, is determined by the very fact it is an urban space. Physical aspects of spatial-ness are reduced to relationism, i.e. it has a meaning for the cultural communication only when the elements of urban topographies are brought into correlation. Other characteristics of physical spatial-ness are irrelevant for such communication. Meaning relations in which elements of urban topographies exist are formed on the very fact of them being urban, that is, the afore mentioned denotation that is ascribed to space, stems from those cultural features and artifacts that are associated in a given milieu with certain concrete elements of urban topographies.

  8. Classic cadherin expressions balance postnatal neuronal positioning and dendrite dynamics to elaborate the specific cytoarchitecture of the mouse cortical area.

    Science.gov (United States)

    Egusa, Saki F; Inoue, Yukiko U; Asami, Junko; Terakawa, Youhei W; Hoshino, Mikio; Inoue, Takayoshi

    2016-04-01

    A unique feature of the mammalian cerebral cortex is in its tangential parcellation via anatomical and functional differences. However, the cellular and/or molecular machinery involved in cortical arealization remain largely unknown. Here we map expression profiles of classic cadherins in the postnatal mouse barrel field of the primary somatosensory area (S1BF) and generate a novel bacterial artificial chromosome transgenic (BAC-Tg) mouse line selectively illuminating nuclei of cadherin-6 (Cdh6)-expressing layer IV barrel neurons to confirm that tangential cellular assemblage of S1BF is established by postnatal day 5 (P5). When we electroporate the cadherins expressed in both barrel neurons and thalamo-cortical axon (TCA) terminals limited to the postnatal layer IV neurons, S1BF cytoarchitecture is disorganized with excess elongation of dendrites at P7. Upon delivery of dominant negative molecules for all classic cadherins, tangential cellular positioning and biased dendritic arborization of barrel neurons are significantly altered. These results underscore the value of classic cadherin-mediated sorting among neuronal cell bodies, dendrites and TCA terminals in postnatally elaborating the S1BF-specific tangential cytoarchitecture. Additionally, how the "protocortex" machinery affects classic cadherin expression profiles in the process of cortical arealization is examined and discussed. Copyright © 2015 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.

  9. Metabolic topography of autoimmune non-paraneoplastic encephalitis

    Energy Technology Data Exchange (ETDEWEB)

    Tripathi, Madhavi; Roy, Shambo Guha; Parida, Girish Kumar; Damle, Nishikant; Shamim, Shamim Ahmed; Bal, Chandrasekhar [All India Institute of Medical Sciences, Department of Nuclear Medicine, New Delhi (India); Tripathi, Manjari; Ihtisham, Kavish; Dash, Deepa [All India Institute of Medical Sciences, Department of Neurology, Cardiothoracic and Neurosciences Centre, New Delhi (India)

    2018-02-15

    F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) is emerging to be a useful tool in supporting the diagnosis of AIE. In this study, we describe the metabolic patterns on F-18 FDG PET imaging in AIE. Twenty-four antibody-positive patients (anti-NMDA-15, anti-VGKC/LGI1-6, and anti-GAD-3), 14 females and 10 males, with an age range of 2-83 years were included in this study. Each PET study was evaluated visually for the presence of hypometabolism or hypermetabolism and semiquantitatively using Cortex ID (GE) and Scenium (Siemens) by measuring regional Z-scores. These patterns were correlated with corresponding antibody positivity once available. Visually, a pattern of hypometabolism, hypermetabolism, or both in various spatial distributions was appreciated in all 24 patients. On quantitative analysis using scenium parietal and occipital lobes showed significant hypometabolism with median Z-score of -3.8 (R) and -3.7 (L) and -2.2 (R) and -2.5 (L) respectively. Two-thirds (16/24) showed significant hypermetabolism involving the basal ganglia with median Z-score of 2.4 (R) and 3.0 (L). Similarly on Cortex ID, the median Z-score for hypometabolism in parietal and occipital lobes was -2.2 (R) and -2.4 (L) and -2.6 (R) and -2.4 (L) respectively, while subcortical regions were not evaluated. MRI showed signal alterations in only 11 of these patients. There is heterogeneity in metabolic topography of AIE which is characterized by hypometabolism most commonly involving the parietal and occipital cortices and hypermetabolism most commonly involving the basal ganglia. Scenium analysis using regional Z-scores can complement visual evaluation for demonstration of these metabolic patterns on FDG PET. (orig.)

  10. Metabolic topography of autoimmune non-paraneoplastic encephalitis.

    Science.gov (United States)

    Tripathi, Madhavi; Tripathi, Manjari; Roy, Shambo Guha; Parida, Girish Kumar; Ihtisham, Kavish; Dash, Deepa; Damle, Nishikant; Shamim, Shamim Ahmed; Bal, Chandrasekhar

    2018-02-01

    F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) is emerging to be a useful tool in supporting the diagnosis of AIE. In this study, we describe the metabolic patterns on F-18 FDG PET imaging in AIE. Twenty-four antibody-positive patients (anti-NMDA-15, anti-VGKC/LGI1-6, and anti-GAD-3), 14 females and 10 males, with an age range of 2-83 years were included in this study. Each PET study was evaluated visually for the presence of hypometabolism or hypermetabolism and semiquantitatively using Cortex ID (GE) and Scenium (Siemens) by measuring regional Z-scores. These patterns were correlated with corresponding antibody positivity once available. Visually, a pattern of hypometabolism, hypermetabolism, or both in various spatial distributions was appreciated in all 24 patients. On quantitative analysis using scenium parietal and occipital lobes showed significant hypometabolism with median Z-score of -3.8 (R) and -3.7 (L) and -2.2 (R) and -2.5 (L) respectively. Two-thirds (16/24) showed significant hypermetabolism involving the basal ganglia with median Z-score of 2.4 (R) and 3.0 (L). Similarly on Cortex ID, the median Z-score for hypometabolism in parietal and occipital lobes was -2.2 (R) and -2.4 (L) and -2.6 (R) and -2.4 (L) respectively, while subcortical regions were not evaluated. MRI showed signal alterations in only 11 of these patients. There is heterogeneity in metabolic topography of AIE which is characterized by hypometabolism most commonly involving the parietal and occipital cortices and hypermetabolism most commonly involving the basal ganglia. Scenium analysis using regional Z-scores can complement visual evaluation for demonstration of these metabolic patterns on FDG PET.

  11. Metabolic topography of autoimmune non-paraneoplastic encephalitis

    International Nuclear Information System (INIS)

    Tripathi, Madhavi; Roy, Shambo Guha; Parida, Girish Kumar; Damle, Nishikant; Shamim, Shamim Ahmed; Bal, Chandrasekhar; Tripathi, Manjari; Ihtisham, Kavish; Dash, Deepa

    2018-01-01

    F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) is emerging to be a useful tool in supporting the diagnosis of AIE. In this study, we describe the metabolic patterns on F-18 FDG PET imaging in AIE. Twenty-four antibody-positive patients (anti-NMDA-15, anti-VGKC/LGI1-6, and anti-GAD-3), 14 females and 10 males, with an age range of 2-83 years were included in this study. Each PET study was evaluated visually for the presence of hypometabolism or hypermetabolism and semiquantitatively using Cortex ID (GE) and Scenium (Siemens) by measuring regional Z-scores. These patterns were correlated with corresponding antibody positivity once available. Visually, a pattern of hypometabolism, hypermetabolism, or both in various spatial distributions was appreciated in all 24 patients. On quantitative analysis using scenium parietal and occipital lobes showed significant hypometabolism with median Z-score of -3.8 (R) and -3.7 (L) and -2.2 (R) and -2.5 (L) respectively. Two-thirds (16/24) showed significant hypermetabolism involving the basal ganglia with median Z-score of 2.4 (R) and 3.0 (L). Similarly on Cortex ID, the median Z-score for hypometabolism in parietal and occipital lobes was -2.2 (R) and -2.4 (L) and -2.6 (R) and -2.4 (L) respectively, while subcortical regions were not evaluated. MRI showed signal alterations in only 11 of these patients. There is heterogeneity in metabolic topography of AIE which is characterized by hypometabolism most commonly involving the parietal and occipital cortices and hypermetabolism most commonly involving the basal ganglia. Scenium analysis using regional Z-scores can complement visual evaluation for demonstration of these metabolic patterns on FDG PET. (orig.)

  12. Shuttle Topography Data Inform Solar Power Analysis

    Science.gov (United States)

    2013-01-01

    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 Topography 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

  13. Evolution of Topography in Glaciated Mountain Ranges

    Science.gov (United States)

    Brocklehurst, Simon H.

    2002-01-01

    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 topography. 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

  14. Downscaling the Local Weather Above Glaciers in Complex Topography

    Science.gov (United States)

    Horak, Johannes; Hofer, Marlis; Gutmann, Ethan; Gohm, Alexander; Rotach, Mathias

    2017-04-01

    Glaciers have experienced a substantial ice-volume loss during the 20th century. To study their response to climate change, process-based glacier mass-balance models (PBGMs) are employed, which require a faithful representation of the state of the atmosphere above the glacier at high spatial and temporal resolution. Glaciers are usually located in complex topography where weather stations are scarce or not existent at all due to the remoteness of such sites and the associated high cost of maintenance. Furthermore. the effective resolution of global circulation models is too large to adequately capture the local topography and represent local weather, which is prerequisite for atmospheric input used by PBGMs. Dynamical downscaling is a physically consistent but computationally expensive approach to bridge the scale gap between GCM output and input needed by PBGMs, while statistical downscaling is faster but requires measurements for training. Both methods have their merits, however, a computationally frugal approach that does not rely on measurements is desirable, especially for long term studies of glacier response to future climate. In this study the intermediate complexity atmospheric research model (ICAR) is employed (Gutmann et al., 2016). It simplifies the wind field physics by relying on analytical solutions derived with linear theory. ICAR then advects atmospheric quantities within this wind field. This allows for computationally fast downscaling and yields a physically consistent set of atmospheric variables. First results obtained from downscaling air temperature, precipitation amount, relative humidity and wind speed to 4 × 4 km2 are presented. Preliminary ICAR is applied for a six month simulation period during five years and evaluated for three domains located in very distinct climates, namely the Southern Alps of New Zealand, the Cordillera Blanca in Peru and the European Alps using ERA Interim reanalysis data (ERAI) as forcing data set. The

  15. Predicting Maximum Lake Depth from Surrounding Topography

    Science.gov (United States)

    Lake volume aids understanding of the physical and ecological dynamics 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. ...

  16. Turbulent Boundary Layer Over Geophysical-like Topographies

    Science.gov (United States)

    Chamorro, L. P.; Hamed, A. M.; Castillo, L.

    2016-12-01

    An experimental investigation of the flow and the turbulence structure over 2D and 3D large-scale wavy walls was performed using high-resolution planar particle image velocimetry in a refractive-index-matching (RIM) channel. Extensive measurements were performed to characterize the developing and developed flows. The 2D wall is described by a sinusoidal wave in the streamwise direction with amplitude to wavelength ratio a/λx = 0.05, while the 3D wall has an additional wave superimposed in the spanwise direction with a/λy = 0.1. The flow over these walls was characterized at Reynolds numbers of 4000 and 40000, based on the bulk velocity and the channel half height. The walls have an amplitude to boundary layer thickness ratio a/δ99 ≈ 0.1 and resemble large-scale and geophysical-like roughnesses found in rivers beds and natural terrain. Instantaneous velocity fields and time-averaged turbulence quantities reveal strong coupling between large-scale topography and the turbulence dynamics near the wall. Turbulence statistics for both walls show the presence of a well-structured shear layer past the roughness crests. Analysis of the turbulent kinetic energy production rate suggests that the shear layer is responsible for the majority of turbulence production across both walls. However, the 3D wall exhibits preferential spanwise flows that are thought to result in the multiple distinctive flow features for the 3D wall including comparatively reduced spanwise vorticity and decreased turbulence levels. Further insight on the effect of roughness three-dimensionality and Reynolds number is drawn in both the developed and developing regions through proper orthogonal decomposition (POD) and quadrant analysis.

  17. Development of a video image-based QA system for the positional accuracy of dynamic tumor tracking irradiation in the Vero4DRT system

    Energy Technology Data Exchange (ETDEWEB)

    Ebe, Kazuyu, E-mail: nrr24490@nifty.com; Tokuyama, Katsuichi; Baba, Ryuta; Ogihara, Yoshisada; Ichikawa, Kosuke; Toyama, Joji [Joetsu General Hospital, 616 Daido-Fukuda, Joetsu-shi, Niigata 943-8507 (Japan); Sugimoto, Satoru [Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo 113-8421 (Japan); Utsunomiya, Satoru; Kagamu, Hiroshi; Aoyama, Hidefumi [Graduate School of Medical and Dental Sciences, Niigata University, Niigata 951-8510 (Japan); Court, Laurence [The University of Texas MD Anderson Cancer Center, Houston, Texas 77030-4009 (United States)

    2015-08-15

    Purpose: To develop and evaluate a new video image-based QA system, including in-house software, that can display a tracking state visually and quantify the positional accuracy of dynamic tumor tracking irradiation in the Vero4DRT system. Methods: Sixteen trajectories in six patients with pulmonary cancer were obtained with the ExacTrac in the Vero4DRT system. Motion data in the cranio–caudal direction (Y direction) were used as the input for a programmable motion table (Quasar). A target phantom was placed on the motion table, which was placed on the 2D ionization chamber array (MatriXX). Then, the 4D modeling procedure was performed on the target phantom during a reproduction of the patient’s tumor motion. A substitute target with the patient’s tumor motion was irradiated with 6-MV x-rays under the surrogate infrared system. The 2D dose images obtained from the MatriXX (33 frames/s; 40 s) were exported to in-house video-image analyzing software. The absolute differences in the Y direction between the center of the exposed target and the center of the exposed field were calculated. Positional errors were observed. The authors’ QA results were compared to 4D modeling function errors and gimbal motion errors obtained from log analyses in the ExacTrac to verify the accuracy of their QA system. The patients’ tumor motions were evaluated in the wave forms, and the peak-to-peak distances were also measured to verify their reproducibility. Results: Thirteen of sixteen trajectories (81.3%) were successfully reproduced with Quasar. The peak-to-peak distances ranged from 2.7 to 29.0 mm. Three trajectories (18.7%) were not successfully reproduced due to the limited motions of the Quasar. Thus, 13 of 16 trajectories were summarized. The mean number of video images used for analysis was 1156. The positional errors (absolute mean difference + 2 standard deviation) ranged from 0.54 to 1.55 mm. The error values differed by less than 1 mm from 4D modeling function errors

  18. Development of a video image-based QA system for the positional accuracy of dynamic tumor tracking irradiation in the Vero4DRT system

    International Nuclear Information System (INIS)

    Ebe, Kazuyu; Tokuyama, Katsuichi; Baba, Ryuta; Ogihara, Yoshisada; Ichikawa, Kosuke; Toyama, Joji; Sugimoto, Satoru; Utsunomiya, Satoru; Kagamu, Hiroshi; Aoyama, Hidefumi; Court, Laurence

    2015-01-01

    Purpose: To develop and evaluate a new video image-based QA system, including in-house software, that can display a tracking state visually and quantify the positional accuracy of dynamic tumor tracking irradiation in the Vero4DRT system. Methods: Sixteen trajectories in six patients with pulmonary cancer were obtained with the ExacTrac in the Vero4DRT system. Motion data in the cranio–caudal direction (Y direction) were used as the input for a programmable motion table (Quasar). A target phantom was placed on the motion table, which was placed on the 2D ionization chamber array (MatriXX). Then, the 4D modeling procedure was performed on the target phantom during a reproduction of the patient’s tumor motion. A substitute target with the patient’s tumor motion was irradiated with 6-MV x-rays under the surrogate infrared system. The 2D dose images obtained from the MatriXX (33 frames/s; 40 s) were exported to in-house video-image analyzing software. The absolute differences in the Y direction between the center of the exposed target and the center of the exposed field were calculated. Positional errors were observed. The authors’ QA results were compared to 4D modeling function errors and gimbal motion errors obtained from log analyses in the ExacTrac to verify the accuracy of their QA system. The patients’ tumor motions were evaluated in the wave forms, and the peak-to-peak distances were also measured to verify their reproducibility. Results: Thirteen of sixteen trajectories (81.3%) were successfully reproduced with Quasar. The peak-to-peak distances ranged from 2.7 to 29.0 mm. Three trajectories (18.7%) were not successfully reproduced due to the limited motions of the Quasar. Thus, 13 of 16 trajectories were summarized. The mean number of video images used for analysis was 1156. The positional errors (absolute mean difference + 2 standard deviation) ranged from 0.54 to 1.55 mm. The error values differed by less than 1 mm from 4D modeling function errors

  19. The effects of surface topography control using liquid crystal elastomers on bodies in flow

    Science.gov (United States)

    Settle, Michael; Guin, Tyler; Beblo, Richard; White, Timothy; Reich, Gregory

    2018-03-01

    Surface topography control has use across many applications including delayed separation of flow via selective boundary-layer tripping. Recently, advances with liquid crystal elastomers (LCE) have been leveraged for controlled, repeatable, out-of-plane deformations that could enable these topographical changes. An aligned LCE deforms when heated, associated with a loss in order. Circumferential patterns fabricated through the thickness of the LCE film yield a predictable conical out-of-plane deformation that can control surface topography. This study focuses on the experimental investigation of LCE behavior for flow control. Initially, the deformations of LCE samples 1/2" in diameter and 50 µm thick were characterized using Digital Image Correlation under uniform positive and negative gauge pressures at various temperatures. Surface topography showed strong dependence on boundary conditions, sample dimensions, and pattern location relative to the applied boundary conditions, informing adjustment of the LCE of the chemistry to produce higher modulus and glassy materials. As an initial demonstration of the ability to control flow, Then, to demonstrate the potential for flow control, 3D printed cylinders with varying arrangements of representative topographical features were characterized in a wind tunnel with Particle Image Velocimetry. Results showed that features with a maximum deflection height of 1.5 mm in a two-row arrangement can form an asymmetric wake about a 73 mm diameter cylinder that reduces drag while generating lift. These results inform subsequent investigation of active LCE elements on a cylinder that are currently under examination.

  20. Assessment of metabolic and mitochondrial dynamics in CD4+ and CD8+ T cells in virologically suppressed HIV-positive individuals on combination antiretroviral therapy.

    Directory of Open Access Journals (Sweden)

    Jesse J R Masson

    Full Text Available Metabolism plays a fundamental role in supporting the growth, proliferation and effector functions of T cells. We investigated the impact of HIV infection on key processes that regulate glucose uptake and mitochondrial biogenesis in subpopulations of CD4+ and CD8+ T cells from 18 virologically-suppressed HIV-positive individuals on combination antiretroviral therapy (cART; median CD4+ cell count: 728 cells/μl and 13 HIV seronegative controls. Mitochondrial membrane potential (MMP and reactive oxygen species (ROS production were also analysed in total CD4+ and CD8+ T cells. Among HIV+/cART individuals, expression of glucose transporter (Glut1 and mitochondrial density were highest within central memory and naïve CD4+ T cells, and lowest among effector memory and transitional memory T cells, with similar trends in HIV-negative controls. Compared to HIV-negative controls, there was a trend towards higher percentage of circulating CD4+Glut1+ T cells in HIV+/cART participants. There were no significant differences in mitochondrial dynamics between subject groups. Glut1 expression was positively correlated with mitochondrial density and MMP in total CD4+ T cells, while MMP was also positively correlated with ROS production in both CD4+ and CD8+ T cells. Our study characterizes specific metabolic features of CD4+ and CD8+ T cells in HIV-negative and HIV+/cART individuals and will invite future studies to explore the immunometabolic consequences of HIV infection.

  1. ATM Coastal Topography-Louisiana, 2001: UTM Zone 15 (Part 1 of 2)

    Science.gov (United States)

    Yates, Xan; Nayegandhi, Amar; Brock, John C.; Sallenger, A.H.; Klipp, Emily S.; Wright, C. Wayne

    2010-01-01

    These remotely sensed, geographically referenced elevation measurements of lidar-derived first-surface (FS) topography 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 a portion of the Louisiana coastline beach face within UTM Zone 15, from Isles Dernieres to Grand Isle, acquired September 7 and 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 topography 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 topography 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

  2. ATM Coastal Topography - Louisiana, 2001: UTM Zone 16 (Part 2 of 2)

    Science.gov (United States)

    Yates, Xan; Nayegandhi, Amar; Brock, John C.; Sallenger, Asbury H.; Klipp, Emily S.; Wright, C. Wayne

    2009-01-01

    These remotely sensed, geographically referenced elevation measurements of lidar-derived first-surface (FS) topography 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 a portion of the Louisiana coastline beach face within UTM Zone 16, from Grand Isle to the Chandeleur Islands, acquired September 7 and 9, 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 topography 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 topography 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

  3. A quantitative method to the analysis of MLC leaf position and speed based on EPID and EBT3 film for dynamic IMRT treatment with different types of MLC.

    Science.gov (United States)

    Li, Yinghui; Chen, Lixin; Zhu, Jinhan; Wang, Bin; Liu, Xiaowei

    2017-07-01

    A quantitative method based on the electronic portal imaging system (EPID) and film was developed for MLC position and speed testing; this method was used for three MLC types (Millennium, MLCi, and Agility MLC). To determine the leaf position, a picket fence designed by the dynamic (DMLC) model was used. The full-width half-maximum (FWHM) values of each gap measured by EPID and EBT3 were converted to the gap width using the FWHM versus nominal gap width relationship. The algorithm developed for the picket fence analysis was able to quantify the gap width, the distance between gaps, and each individual leaf position. To determine the leaf speed, a 0.5 × 20 cm 2 MLC-defined sliding gap was applied across a 14 × 20 cm 2 symmetry field. The linacs ran at a fixed-dose rate. The use of different monitor units (MUs) for this test led to different leaf speeds. The effect of leaf transmission was considered in a speed accuracy analysis. The difference between the EPID and film results for the MLC position is less than 0.1 mm. For the three MLC types, twice the standard deviation (2 SD) is provided; 0.2, 0.4, and 0.4 mm for gap widths of three MLC types, and 0.1, 0.2, and 0.2 mm for distances between gaps. The individual leaf positions deviate from the preset positions within 0.1 mm. The variations in the speed profiles for the EPID and EBT3 results are consistent, but the EPID results are slightly better than the film results. Different speeds were measured for each MLC type. For all three MLC types, speed errors increase with increasing speed. The analysis speeds deviate from the preset speeds within approximately 0.01 cm s -1 . This quantitative analysis of MLC position and speed provides an intuitive evaluation for MLC quality assurance (QA). © 2017 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

  4. High frequency seismic signal generated by landslides on complex topographies: from point source to spatially distributed sources

    Science.gov (United States)

    Mangeney, A.; Kuehnert, J.; Capdeville, Y.; Durand, V.; Stutzmann, E.; Kone, E. H.; Sethi, S.

    2017-12-01

    During their flow along the topography, landslides generate seismic waves in a wide frequency range. These so called landquakes can be recorded at very large distances (a few hundreds of km for large landslides). The recorded signals depend on the landslide seismic source and the seismic wave propagation. If the wave propagation is well understood, the seismic signals can be inverted for the seismic source and thus can be used to get information on the landslide properties and dynamics. Analysis and modeling of long period seismic signals (10-150s) have helped in this way to discriminate between different landslide scenarios and to constrain rheological parameters (e.g. Favreau et al., 2010). This was possible as topography poorly affects wave propagation at these long periods and the landslide seismic source can be approximated as a point source. In the near-field and at higher frequencies (> 1 Hz) the spatial extent of the source has to be taken into account and the influence of the topography on the recorded seismic signal should be quantified in order to extract information on the landslide properties and dynamics. The characteristic signature of distributed sources and varying topographies is studied as a function of frequency and recording distance.The time dependent spatial distribution of the forces applied to the ground by the landslide are obtained using granular flow numerical modeling on 3D topography. The generated seismic waves are simulated using the spectral element method. The simulated seismic signal is compared to observed seismic data from rockfalls at the Dolomieu Crater of Piton de la Fournaise (La Réunion).Favreau, P., Mangeney, A., Lucas, A., Crosta, G., and Bouchut, F. (2010). Numerical modeling of landquakes. Geophysical Research Letters, 37(15):1-5.

  5. [Effect of irregular bedrock topography on the soil profile pattern of water content in a Karst hillslope.

    Science.gov (United States)

    Jia, Jin Tian; Fu, Zhi Yong; Chen, Hong Song; Wang, Ke Lin; Zhou, Wei Jun

    2016-06-01

    Based on three manually excavated trenches (projection length of 21 m, width of 1 m) along a typical Karst hillslope, the changing trends for soil-bedrock structure, average water content of soil profile and soil-bedrock interface water content along each individual trench were studied. The effect of irregular bedrock topography on soil moisture distribution was discussed. The results showed that the surface topography was inconsistent with the bedrock topography in the Karst hill-slopes. The bedrock topography was highly irregular with a maximum variation coefficient of 82%. The distribution pattern of soil profile of moisture was significantly affected by the underlying undulant bedrock. The soil water content was related to slope position when the fluctuation was gentle, and displayed a linear increase from upslope to downslope. When the bedrock fluctuation increased, the downslope linear increasing trend for soil water content became unapparent, and the spatial continuity of soil moisture was weakened. The soil moisture was converged in rock dents and cracks. The average water content of soil profile was significantly positively correlated with the soil-bedrock interface water content, while the latter responded more sensitively to the bedrock fluctuation.

  6. Geology, Bedrock - BEDROCK_TOPOGRAPHY_MM36_IN: Bedrock Topography Contours, Indiana (Indiana Geological Survey, 1:500,000, Line Shapefile)

    Data.gov (United States)

    NSGIC State | GIS Inventory — Bedrock topography was converted from the original published map, Indiana Geological Survey Miscellaneous Map 36. The contours define the elevation/topography of the...

  7. The influence of surface topography on Kelvin probe force microscopy

    International Nuclear Information System (INIS)

    Sadewasser, S; Leendertz, C; Streicher, F; Lux-Steiner, M Ch

    2009-01-01

    Long-range electrostatic forces govern the imaging mechanism in electrostatic force microscopy as well as in Kelvin probe force microscopy. To improve the analysis of such images, simulations of the electrostatic field distribution have been performed in the past using a flat surface and a cone-shaped tip. However, the electrostatic field distribution between a tip and a sample depends strongly on the surface topography, which has been neglected in previous studies. It is therefore of general importance to study the influence of sample topography features on Kelvin probe force microscopy images, which we address here by performing finite element simulations. We show how the surface potential measurement is influenced by surface steps and surface grooves, considering potential variations in the form of a potential peak and a potential step. The influence of the topography on the measurement of the surface potential is found to be rather small compared to a typical experimental resolution. Surprisingly, in the case of a coinciding topography and potential step an improvement of the potential profile due to the inclusion of the topography is observed. Finally, based on the obtained results, suggestions for the realization of KPFM measurement are given.

  8. Smoking topography and abstinence in adult female smokers.

    Science.gov (United States)

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

    2013-12-01

    Preliminary evidence, within both adults and adolescents, suggests that the intensity with which cigarettes are smoked (i.e., smoking topography) is predictive of success during a cessation attempt. These reports have also shown topography to be superior compared to other variables, such as cigarettes per day, in the prediction of abstinence. The possibility that gender may influence this predictive relationship has not been evaluated but may be clinically useful in tailoring gender-specific interventions. Within the context of a clinical trial for smoking cessation among women, adult daily smokers completed a laboratory session that included a 1-hour ad libitum smoking period in which measures of topography were collected (N=135). Participants were then randomized to active medication (nicotine patch vs. varenicline) and abstinence was monitored for 4weeks. Among all smoking topography measures and all abstinence outcomes, a moderate association was found between longer puff duration and greater puff volume and continued smoking during the active 4-week treatment phase, but only within the nicotine patch group. Based on the weak topography-abstinence relationship among female smokers found in the current study, future studies should focus on explicit gender comparisons to examine if these associations are specific to or more robust in male smokers. © 2013 Elsevier Ltd. All rights reserved.

  9. Toroidal vortices over isolated topography in geophysical flows

    International Nuclear Information System (INIS)

    Koshel, Konstantin V; Ryzhov, Evgeny A; Zyryanov, Valery N

    2014-01-01

    This work deals with a model of a topographically trapped vortex appearing over isolated topography in a geophysical flow. The main feature of the study is that we pay special attention to the vertical structure of a topographically trapped vortex. The model considered allows one to study the vertical motion which is known not to be negligible in many cases. Given topography in the form of an isolated cylinder, and radial symmetry and stationarity of a uniform flow, in the linear approximation, we formulate a boundary value problem that determines all the components of the velocity field through a six-order differential operator, and nonincreasing boundary conditions at the center of the topography, and at infinity. The eigenvalues of the boundary value problem correspond to bifurcation points, in which the flow becomes unstable, hence non-negligible vertical velocities occur. We formulate a condition for the boundary value problem to have a discrete spectrum of these bifurcation points, and hence to be solvable. Conducting a series of test calculations, we show that the resulting vortex lies in the vicinity of topography, and can attain the distance up to half of the topography characteristic radius. (papers)

  10. Autism Symptom Topography and Maternal Socioemotional Functioning

    Science.gov (United States)

    Ekas, Naomi; Whitman, Thomas L.

    2010-01-01

    Researchers examining the relationship of autism "symptomatology" and maternal stress have defined symptomatology in terms of level of severity, frequency of occurrence, or symptom type. In the present study, the relationship of maternal perceptions of these dimensions, along with a fourth, symptom diversity, and negative and positive indices of…

  11. Measuring surface topography with scanning electron microscopy. I. EZEImage: a program to obtain 3D surface data.

    Science.gov (United States)

    Ponz, Ezequiel; Ladaga, Juan Luis; Bonetto, Rita Dominga

    2006-04-01

    Scanning electron microscopy (SEM) is widely used in the science of materials and different parameters were developed to characterize the surface roughness. In a previous work, we studied the surface topography with fractal dimension at low scale and two parameters at high scale by using the variogram, that is, variance vs. step log-log graph, of a SEM image. Those studies were carried out with the FERImage program, previously developed by us. To verify the previously accepted hypothesis by working with only an image, it is indispensable to have reliable three-dimensional (3D) surface data. In this work, a new program (EZEImage) to characterize 3D surface topography in SEM has been developed. It uses fast cross correlation and dynamic programming to obtain reliable dense height maps in a few seconds which can be displayed as an image where each gray level represents a height value. This image can be used for the FERImage program or any other software to obtain surface topography characteristics. EZEImage also generates anaglyph images as well as characterizes 3D surface topography by means of a parameter set to describe amplitude properties and three functional indices for characterizing bearing and fluid properties.

  12. Comparison of dynamic monitoring strategies based on CD4 cell counts in virally suppressed, HIV-positive individuals on combination antiretroviral therapy in high-income countries: a prospective, observational study

    NARCIS (Netherlands)

    Caniglia, Ellen C.; Cain, Lauren E.; Sabin, Caroline A.; Robins, James M.; Logan, Roger; Abgrall, Sophie; Mugavero, Michael J.; Hernández-Díaz, Sonia; Meyer, Laurence; Seng, Remonie; Drozd, Daniel R.; Seage, George R.; Bonnet, Fabrice; Dabis, Francois; Moore, Richard D.; Reiss, Peter; van Sighem, Ard; Mathews, William C.; del Amo, Julia; Moreno, Santiago; Deeks, Steven G.; Muga, Roberto; Boswell, Stephen L.; Ferrer, Elena; Eron, Joseph J.; Napravnik, Sonia; Jose, Sophie; Phillips, Andrew; Justice, Amy C.; Tate, Janet P.; Gill, John; Pacheco, Antonio; Veloso, Valdilea G.; Bucher, Heiner C.; Egger, Matthias; Furrer, Hansjakob; Porter, Kholoud; Touloumi, Giota; Crane, Heidi; Miro, Jose M.; Sterne, Jonathan A.; Costagliola, Dominique; Saag, Michael; Hernán, Miguel A.

    2017-01-01

    Clinical guidelines vary with respect to the optimal monitoring frequency of HIV-positive individuals. We compared dynamic monitoring strategies based on time-varying CD4 cell counts in virologically suppressed HIV-positive individuals. In this observational study, we used data from prospective

  13. Linking topography to tonotopy in the mouse auditory thalamocortical circuit

    DEFF Research Database (Denmark)

    Hackett, Troy A; Rinaldi Barkat, Tania; O'Brien, Barbara M J

    2011-01-01

    The mouse sensory neocortex is reported to lack several hallmark features of topographic organization such as ocular dominance and orientation columns in primary visual cortex or fine-scale tonotopy in primary auditory cortex (AI). Here, we re-examined the question of auditory functional topography...... the tonotopic axis in the slice produced an orderly shift of voltage-sensitive dye (VSD) signals along the AI tonotopic axis, demonstrating topography in the mouse thalamocortical circuit that is preserved in the slice. However, compared with BF maps of neuronal spiking activity, the topographic order...... of subthreshold VSD maps was reduced in layer IV and even further degraded in layer II/III. Therefore, the precision of AI topography varies according to the source and layer of the mapping signal. Our findings further bridge the gap between in vivo and in vitro approaches for the detailed cellular study...

  14. On in-vivo skin topography metrology and replication techniques

    International Nuclear Information System (INIS)

    Rosen, B-G; Blunt, L; Thomas, T R

    2005-01-01

    Human skin metrology is an area of growing interest for many disciplines both in research and for commercial purposes. Changes in the skin topography are an early stage diagnosis tool not only for diseases but also give indication of the response to medical and cosmetic treatment. This paper focuses on the evaluation of in vivo and in vitro methodologies for accurate measurements of skin and outlines the quantitative characterisation of the skin topography. The study shows the applicability of in-vivo skin topography characterisation and also the advantages and limitations compared to conventional replication techniques. Finally, aspects of stripe projection methodology and 3D characterisation are discussed as a background to the proposed methodology in this paper

  15. Crystal quality analysis and improvement using x-ray topography

    International Nuclear Information System (INIS)

    Maj, J.; Goetze, K.; Macrander, A.; Zhong, Y.; Huang, X.; Maj, L.

    2008-01-01

    The Topography X-ray Laboratory of the Advanced Photon Source (APS) at Argonne National Laboratory operates as a collaborative effort with APS users to produce high performance crystals for APS X-ray beamline experiments. For many years the topography laboratory has worked closely with an on-site optics shop to help ensure the production of crystals with the highest quality, most stress-free surface finish possible. It has been instrumental in evaluating and refining methods used to produce high quality crystals. Topographical analysis has shown to be an effective method to quantify and determine the distribution of stresses, to help identify methods that would mitigate the stresses and improve the Rocking curve, and to create CCD images of the crystal. This paper describes the topography process and offers methods for reducing crystal stresses in order to substantially improve the crystal optics.

  16. High Dynamics and Precision Optical Measurement Using a Position Sensitive Detector (PSD in Reflection-Mode: Application to 2D Object Tracking over a Smart Surface

    Directory of Open Access Journals (Sweden)

    Ioan Alexandru Ivan

    2012-12-01

    Full Text Available When related to a single and good contrast object or a laser spot, position sensing, or sensitive, detectors (PSDs have a series of advantages over the classical camera sensors, including a good positioning accuracy for a fast response time and very simple signal conditioning circuits. To test the performance of this kind of sensor for microrobotics, we have made a comparative analysis between a precise but slow video camera and a custom-made fast PSD system applied to the tracking of a diffuse-reflectivity object transported by a pneumatic microconveyor called Smart-Surface. Until now, the fast system dynamics prevented the full control of the smart surface by visual servoing, unless using a very expensive high frame rate camera. We have built and tested a custom and low cost PSD-based embedded circuit, optically connected with a camera to a single objective by means of a beam splitter. A stroboscopic light source enhanced the resolution. The obtained results showed a good linearity and a fast (over 500 frames per second response time which will enable future closed-loop control by using PSD.

  17. Relationships Between Simple Toe Elevation Angle in the Standing Position and Dynamic Balance and Fall Risk Among Community-Dwelling Older Adults.

    Science.gov (United States)

    Takatori, Katsuhiko; Matsumoto, Daisuke

    2015-10-01

    To investigate the relationships between toe elevation ability in the standing position and dynamic balance and fall risk among community-dwelling older adults. Cross-sectional survey. General community. Community-dwelling older adults (N = 287). Toe elevation angles in the standing position. Intra-rater and inter-rater reliability of measurements of the toe elevation angle was high (internal coefficient of correlation [ICC] (1,2) = 0.94 for the former and ICC (2,1) = 0.90 for the latter). Significant correlations were found between the toe elevation angle and age (r = -0.20, P fall in the previous 6 months had a significantly lower toe elevation angle compared with subjects who did not experience a fall (t = 2.19, P balance ability and appears to be a simple screening test for fall risk in community-dwelling older adults. Copyright © 2015 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

  18. Real-Space Analysis of Scanning Tunneling Microscopy Topography Datasets Using Sparse Modeling Approach

    Science.gov (United States)

    Miyama, Masamichi J.; Hukushima, Koji

    2018-04-01

    A sparse modeling approach is proposed for analyzing scanning tunneling microscopy topography data, which contain numerous peaks originating from the electron density of surface atoms and/or impurities. The method, based on the relevance vector machine with L1 regularization and k-means clustering, enables separation of the peaks and peak center positioning with accuracy beyond the resolution of the measurement grid. The validity and efficiency of the proposed method are demonstrated using synthetic data in comparison with the conventional least-squares method. An application of the proposed method to experimental data of a metallic oxide thin-film clearly indicates the existence of defects and corresponding local lattice distortions.

  19. Spray-coatable negative photoresist for high topography MEMS applications

    International Nuclear Information System (INIS)

    Arnold, Markus; Haas, Sven; Schwenzer, Falk; Schwenzer, Gunther; Reuter, Danny; Geßner, Thomas; Voigt, Anja; Gruetzner, Gabi

    2017-01-01

    In microsystem technology, the lithographical processing of substrates with a topography is very important. Interconnecting lines, which are routed over sloped topography sidewalls from the top of the protecting wafer to the contact pads of the device wafer, are one example of patterning over a topography. For structuring such circuit paths, a photolithography process, and therefore a process for homogeneous photoresist coating, is required. The most flexible and advantageous way of depositing a homogeneous photoresist film over structures with high topography steps is spray-coating. As a pattern transfer process for circuit paths in cavities, the lift-off process is widely used. A negative resist, like ma-N (MRT) or AZnLOF (AZ) is favoured for lift-off processes due to the existing negative angle of the sidewalls. Only a few sprayable negative photoresists are commercially available. In this paper, the development of a novel negative resist spray-coating based on a commercially available single-layer lift-off resist for spin-coating, especially for the patterning of structures inside the cavity and on the cavity wall, is presented. A variety of parameters influences the spray-coating process, and therefore the patterning results. Besides the spray-coating tool and the parameters, the composition of the resist solution itself also influences the coating results. For homogeneous resist coverage over the topography of the substrate, different solvent combinations for diluting the resist solution, different chuck temperatures during the coating process, and also the softbake conditions, are all investigated. The solvent formulations and the process conditions are optimized with respect to the homogeneity of the resist coverage on the top edge of the cavities. Finally, the developed spray-coating process, the resist material and the process stability are demonstrated by the following applications: (i) lift-off, (ii) electroplating, (iii) the wet and (iv) the dry

  20. Effects of Topography-driven Micro-climatology on Evaporation

    Science.gov (United States)

    Adams, D. D.; Boll, J.; Wagenbrenner, N. S.

    2017-12-01

    The effects of spatial-temporal variation of climatic conditions on evaporation in micro-climates are not well defined. Current spatially-based remote sensing and modeling for evaporation is limited for high resolutions and complex topographies. We investigated the effect of topography-driven micro-climatology on evaporation supported by field measurements and modeling. Fourteen anemometers and thermometers were installed in intersecting transects over the complex topography of the Cook Agronomy Farm, Pullman, WA. WindNinja was used to create 2-D vector maps based on recorded observations for wind. Spatial analysis of vector maps using ArcGIS was performed for analysis of wind patterns and variation. Based on field measurements, wind speed and direction show consequential variability based on hill-slope location in this complex topography. Wind speed and wind direction varied up to threefold and more than 45 degrees, respectively for a given time interval. The use of existing wind models enables prediction of wind variability over the landscape and subsequently topography-driven evaporation patterns relative to wind. The magnitude of the spatial-temporal variability of wind therefore resulted in variable evaporation rates over the landscape. These variations may contribute to uneven crop development patterns observed during the late growth stages of the agricultural crops at the study location. Use of hill-slope location indexes and appropriate methods for estimating actual evaporation support development of methodologies to better define topography-driven heterogeneity in evaporation. The cumulative effects of spatially-variable climatic factors on evaporation are important to quantify the localized water balance and inform precision farming practices.

  1. Difference in diaphragmatic motion during tidal breathing in a standing position between COPD patients and normal subjects: Time-resolved quantitative evaluation using dynamic chest radiography with flat panel detector system (“dynamic X-ray phrenicography”)

    International Nuclear Information System (INIS)

    Yamada, Yoshitake; Ueyama, Masako; Abe, Takehiko; Araki, Tetsuro; Abe, Takayuki; Nishino, Mizuki; Jinzaki, Masahiro; Hatabu, Hiroto

    2017-01-01

    Highlights: • Dynamic X-ray phrenicography is a useful method for the evaluation of the diaphragms. • Its radiation dose is comparable to conventional two projection chest radiography. • Diaphragm motion during tidal breathing is larger in COPD than in normal subjects. • Higher BMI is also associated with increased excursions of the bilateral diaphragm. - Abstract: Objectives: To quantitatively compare diaphragmatic motion during tidal breathing in a standing position between chronic obstructive pulmonary disease (COPD) patients and normal subjects using dynamic chest radiography. Materials and methods: Thirty-nine COPD patients (35 males; age, 71.3 ± 8.4 years) and 47 normal subjects (non-smoker healthy volunteers) (20 males; age, 54.8 ± 9.8 years) underwent sequential chest radiographs during tidal breathing using dynamic chest radiography with a flat panel detector system. We evaluated the excursions and peak motion speeds of the diaphragms. The results were analyzed using an unpaired t-test and a multiple linear regression model. Results: The excursions of the diaphragms in COPD patients were significantly larger than those in normal subjects (right, 14.7 ± 5.5 mm vs. 10.2 ± 3.7 mm, respectively, P < 0.001; left, 17.2 ± 4.9 mm vs. 14.9 ± 4.2 mm, respectively, P = 0.022). Peak motion speeds in inspiratory phase were significantly faster in COPD patients compared to normal subjects (right, 16.3 ± 5.0 mm/s vs. 11.8 ± 4.2 mm/s, respectively, P < 0.001; left, 18.9 ± 4.9 mm/s vs. 16.7 ± 4.0 mm/s, respectively, P = 0.022). The multivariate analysis demonstrated that having COPD and higher body mass index were independently associated with increased excursions of the bilateral diaphragm (all P < 0.05), after adjusting for other clinical variables. Conclusions: Time-resolved quantitative evaluation of the diaphragm using dynamic chest radiography demonstrated that the diaphragmatic motion during tidal breathing in a standing position is larger and

  2. Difference in diaphragmatic motion during tidal breathing in a standing position between COPD patients and normal subjects: Time-resolved quantitative evaluation using dynamic chest radiography with flat panel detector system (“dynamic X-ray phrenicography”)

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, Yoshitake, E-mail: yamada@rad.med.keio.ac.jp [Department of Radiology, Center for Pulmonary Functional Imaging, Brigham and Women’s Hospital, Harvard Medical School, 75 Francis St., Boston, MA 02215 (United States); Department of Diagnostic Radiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582 (Japan); Ueyama, Masako, E-mail: ueyamam@fukujuji.org [Department of Health Care, Fukujuji Hospital, Japan Anti-Tuberculosis Association, 3-1-24 Matsuyama, Kiyose, Tokyo 204-8522 (Japan); Abe, Takehiko, E-mail: takehikoabe@hotmail.com [Department of Radiology, Fukujuji Hospital, Japan Anti-Tuberculosis Association, 3-1-24 Matsuyama, Kiyose, Tokyo 204-8522 (Japan); Araki, Tetsuro, E-mail: TARAKI@partners.org [Department of Radiology, Center for Pulmonary Functional Imaging, Brigham and Women’s Hospital, Harvard Medical School, 75 Francis St., Boston, MA 02215 (United States); Abe, Takayuki, E-mail: abe.t@keio.jp [Department of Preventive Medicine and Public Health, Biostatistics Unit at Clinical and Translational Research Center, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582 (Japan); Nishino, Mizuki, E-mail: Mizuki_Nishino11@dfci.harvard.edu [Department of Radiology, Center for Pulmonary Functional Imaging, Brigham and Women’s Hospital, Harvard Medical School, 75 Francis St., Boston, MA 02215 (United States); Jinzaki, Masahiro, E-mail: jinzaki@rad.med.keio.ac.jp [Department of Diagnostic Radiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582 (Japan); Hatabu, Hiroto, E-mail: hhatabu@partners.org [Department of Radiology, Center for Pulmonary Functional Imaging, Brigham and Women’s Hospital, Harvard Medical School, 75 Francis St., Boston, MA 02215 (United States); and others

    2017-02-15

    Highlights: • Dynamic X-ray phrenicography is a useful method for the evaluation of the diaphragms. • Its radiation dose is comparable to conventional two projection chest radiography. • Diaphragm motion during tidal breathing is larger in COPD than in normal subjects. • Higher BMI is also associated with increased excursions of the bilateral diaphragm. - Abstract: Objectives: To quantitatively compare diaphragmatic motion during tidal breathing in a standing position between chronic obstructive pulmonary disease (COPD) patients and normal subjects using dynamic chest radiography. Materials and methods: Thirty-nine COPD patients (35 males; age, 71.3 ± 8.4 years) and 47 normal subjects (non-smoker healthy volunteers) (20 males; age, 54.8 ± 9.8 years) underwent sequential chest radiographs during tidal breathing using dynamic chest radiography with a flat panel detector system. We evaluated the excursions and peak motion speeds of the diaphragms. The results were analyzed using an unpaired t-test and a multiple linear regression model. Results: The excursions of the diaphragms in COPD patients were significantly larger than those in normal subjects (right, 14.7 ± 5.5 mm vs. 10.2 ± 3.7 mm, respectively, P < 0.001; left, 17.2 ± 4.9 mm vs. 14.9 ± 4.2 mm, respectively, P = 0.022). Peak motion speeds in inspiratory phase were significantly faster in COPD patients compared to normal subjects (right, 16.3 ± 5.0 mm/s vs. 11.8 ± 4.2 mm/s, respectively, P < 0.001; left, 18.9 ± 4.9 mm/s vs. 16.7 ± 4.0 mm/s, respectively, P = 0.022). The multivariate analysis demonstrated that having COPD and higher body mass index were independently associated with increased excursions of the bilateral diaphragm (all P < 0.05), after adjusting for other clinical variables. Conclusions: Time-resolved quantitative evaluation of the diaphragm using dynamic chest radiography demonstrated that the diaphragmatic motion during tidal breathing in a standing position is larger and

  3. Positive and negative feedback loops in nutrient phytoplankton interactions related to climate dynamics factors in a shallow temperate estuary (Vistula Lagoon, southern Baltic)

    Science.gov (United States)

    Kruk, Marek; Kobos, Justyna; Nawrocka, Lidia; Parszuto, Katarzyna

    2018-04-01

    This study aims to demonstrate that factors associated with climate dynamics, such as temperature and wind, affect the ecosystem of the shallow Vistula Lagoon in the southern Baltic and cause nutrient forms phytoplankton interactions: the growth of biomass and constraints of it. This occurs through a network of direct and indirect relationships between environmental and phytoplankton factors, including interactions of positive and negative feedback loops. Path analysis supported by structural equation modeling (SEM) was used to test hypotheses regarding the impact of climate factors on algal assemblages. Increased phytoplankton biomass was affected directly by water temperature and salinity, while the wind speed effect was indirect as it resulted in increased concentrations of suspended solids (SS) in the water column. Simultaneously, the concentration of SS in the water was positively correlated with particulate organic carbon (POC), particulate nitrogen (PN), and particulate phosphorus (PP), and was negatively correlated with the total nitrogen to phosphorus (N:P) ratio. Particulate forms of C, N, and phosphorus (P), concentrations of soluble reactive phosphorus (SRP) and nitrate and nitrite nitrogen (NO3-N + NO2-N), and ratios of the total N:P and DIN:SRP, all indirectly effected Cyanobacteria C concentrations. These processes influence other phytoplankton groups (Chlorophyta, Bacillariophyceae and the picophytoplankton fraction). Increased levels of SRP associated with organic matter (POC), which stemmed from reduced DIN:SRP ratios, contributed to increased Cyanoprokaryota and picophytoplankton C concentrations, which created a positive feedback loop. However, a simultaneous reduction in the total N:P ratio could have inhibited increases in the biomass of these assemblages by limiting N, which likely formed a negative feedback loop. The study indicates that the nutrients-phytoplankton feedback loop phenomenon can intensify eutrophication in a temperate lagoon

  4. Different ways to handle topography in practical geoid determination

    DEFF Research Database (Denmark)

    Dahl, O.C.; Forsberg, René

    1999-01-01

    In this paper two different methods of how to handle topography in geoid determination is investigated. First method employs the Residual Terrain Model (RTM) remove-restore technique and yields the quasigeoid, whereas the second method is the classical Helmert condensation method, yielding...... the topography was represented by either a detailed (100 m) or a coarse (1000 m) digital terrain model. The inclusion of bathymetry in the terrain model was also investigated. Even if two different methods were used, they produced almost identical results at the 5 cm level in the mountains, but small systematic...

  5. Airborne Instrument Simulator for the Lidar Surface Topography (LIST) Mission

    Science.gov (United States)

    Yu, Anthony W.; Krainak, Michael A.; Harding, David J.; Abshire, James B.; Sun, Xiaoli; Cavanaugh, John; Valett, Susan; Ramos-Izquierdo, Luis

    2010-01-01

    In 2007, the National Research Council (NRC) completed its first decadal survey for Earth science at the request of NASA, NOAA, and USGS. The Lidar Surface Topography (LIST) mission is one of fifteen missions recommended by NRC, whose primary objectives are to map global topography and vegetation structure at 5 m spatial resolution, and to acquire global coverage with a few years. NASA Goddard conducted an initial mission concept study for the LIST mission 2007, and developed the initial measurement requirements for the mission.

  6. Topography measurements and applications in ballistics and tool mark identifications*

    Science.gov (United States)

    Vorburger, T V; Song, J; Petraco, N

    2016-01-01

    The application of surface topography measurement methods to the field of firearm and toolmark analysis is fairly new. The field has been boosted by the development of a number of competing optical methods, which has improved the speed and accuracy of surface topography acquisitions. We describe here some of these measurement methods as well as several analytical methods for assessing similarities and differences among pairs of surfaces. We also provide a few examples of research results to identify cartridge cases originating from the same firearm or tool marks produced by the same tool. Physical standards and issues of traceability are also discussed. PMID:27182440

  7. Airborne Lidar Simulator for the Lidar Surface Topography (LIST) Mission

    Science.gov (United States)

    Yu, Anthony W.; Krainak, Michael A.; Abshire, James B.; Cavanaugh, John; Valett, Susan; Ramos-Izquierdo, Luis

    2010-01-01

    In 2007, the National Research Council (NRC) completed its first decadal survey for Earth science at the request of NASA, NOAA, and USGS. The Lidar Surface Topography (LIST) mission is one of fifteen missions recommended by NRC, whose primary objectives are to map global topography and vegetation structure at 5 m spatial resolution, and to acquire global surface height mapping within a few years. NASA Goddard conducted an initial mission concept study for the LIST mission in 2007, and developed the initial measurement requirements for the mission.

  8. Influence of topography on landscape radiation temperature distribution

    International Nuclear Information System (INIS)

    Florinsky, I.V.; Kulagina, T.B.; Meshalkina, J.L.

    1994-01-01

    The evaluation of the influence of topography on landscape radiation temperature distribution is carried out by statistical processing of digital models of elevation, gradient, aspect, horizontal, vertical and mean land surface curvatures and the infrared thermal scene generated by the Thermovision 880 system. Significant linear correlation coefficients between the landscape radiation temperature and elevation, slope, aspect, vertical and mean landsurface curvatures are determined, being —0-57, 0 38, 0-26, 015, 013, respectively. The equation of the topography influence on the distribution of the landscape radiation temperature is defined. (author)

  9. Venus gravity and topography: 60th degree and order model

    Science.gov (United States)

    Konopliv, A. S.; Borderies, N. J.; Chodas, P. W.; Christensen, E. J.; Sjogren, W. L.; Williams, B. G.; Balmino, G.; Barriot, J. P.

    1993-01-01

    We have combined the most recent Pioneer Venus Orbiter (PVO) and Magellan (MGN) data with the earlier 1978-1982 PVO data set to obtain a new 60th degree and order spherical harmonic gravity model and a 120th degree and order spherical harmonic topography model. Free-air gravity maps are shown over regions where the most marked improvement has been obtained (Ishtar-Terra, Alpha, Bell and Artemis). Gravity versus topography relationships are presented as correlations per degree and axes orientation.

  10. Venus gravity anomalies and their correlations with topography

    Science.gov (United States)

    Sjogren, W. L.; Bills, B. G.; Birkeland, P. W.; Esposito, P. B.; Konopliv, A. R.; Mottinger, N. A.; Ritke, S. J.; Phillips, R. J.

    1983-01-01

    This report provides a summary of the high-resolution gravity data obtained from the Pioneer Venus Orbiter radio tracking data. Gravity maps, covering a 70 deg latitude band through 360 deg of longitude, are displayed as line-of-sight and vertical gravity. Topography converted to gravity and Bouguer gravity maps are also shown in both systems. Topography to gravity ratios are made over several regions of the planet. There are markedly different ratios for the Aphrodite area as compared to the Beta and Atla areas.

  11. The Effects of Micro- and Nano-Topography on Cells

    DEFF Research Database (Denmark)

    Kolind, Kristian

    2013-01-01

    the effect of topography on cells has received much attention understanding how important this is for the rational design of bio-interfaces. Nevertheless, there is still a limited understanding of the effect of topography on cells making it impossible to tailor a biomaterial with specific cellular activity......Cells continuously make decisions on what proteins to express, and when to divide, differentiate and commit suicide, through a complex network of intracellular processes. The signals that determine the cellular processes reside within the extracellular matrix. They involve soluble signaling...

  12. Hydrophobic Surfaces: Topography Effects on Wetting by Supercooled Water and Freezing Delay

    DEFF Research Database (Denmark)

    Heydari, Golrokh; Thormann, Esben; Järn, Mikael

    2013-01-01

    Hydrophobicity, and in particular superhydrophobicity, has been extensively considered to promote ice-phobicity. Dynamic contact angle measurements above 0 °C have been widely used to evaluate the water repellency. However, it is the wetting properties of supercooled water at subzero temperatures...... and the derived work of adhesion that are important for applications dealing with icing. In this work we address this issue by determining the temperature-dependent dynamic contact angle of microliter-sized water droplets on a smooth hydrophobic and a superhydrophobic surface with similar surface chemistry....... The data highlight how the work of adhesion of water in the temperature interval from about 25 °C to below −10 °C is affected by surface topography. A marked decrease in contact angle on the superhydrophobic surface is observed with decreasing temperature, and we attribute this to condensation below...

  13. Monitoring of desert dune topography by multi angle sensors

    Science.gov (United States)

    Yun, J.; Kim, J.; Choi, Y.; Yun, H.

    2011-12-01

    Nowadays, the sandy desert is rapidly expanding world widely and results in a lot of risks in the socio-econimical aspects as well as the anthropogenic activities. For example, the increasing occurrences of mineral dust storm which presumably originated from the sandy deserts in northwest China become a serious threat in human activities as well as public health over Far East Asian area as the interpretation by the MODIS analysis (Zhang et al., 2007) and the particle trajectory simulation with HYSPLYT (HYbrid Single-Particle Lagrangian Integrated Trajectory) (Kim et al., 2011) identified. Since the sand dune activity has been recognized as an essential indicator of the progressive desertification, it is important to establish the monitoring method for the variations of topographic properties by the dune activities such as local roughness. Thus it will provide the crucial data about the extent and the transition of sandy desert. For example, it is well known the aerodynamic roughness lengths Zo which can be driven from the specialized sensor such as POLDER (POLarization and Directionality of the Earth's Reflectances) is essential to understand desert dune characteristics. However, for the multi temporal observation of dune fields, the availability of data set to extract Zo is limited. Therefore, we employed MISR (Multi angle imaging Spectro Radiometer) image sequence to extract multi angle topographic parameters such as NDAI (Normalized Difference Angular Index) or the variation of radiance with the viewing geometry which are representing the characteristics of target desert topography instead of Zo. In our approach, NDAI were expanded to the all viewing angles and then compared over the target sandy desert and the surrounding land covers. It showed very strong consistencies according to the land cover type and especially over the dynamic dune fields. On the other hands, the variation of NDAIs of sandy desert combining with the metrological observations were

  14. Change Detection Of Seafloor Topography By Modeling Multitemporal Multibeam Echosounder Measurements

    Science.gov (United States)

    Zirek, E.; Sunar, F.

    2014-09-01

    The term "topography" implies the study of numerous landforms that exist on or below the Earth and a detailed knowledge of topography is required to understand the most Earth processes. In the oceans, sea floor topography refers the geographic features of the sea floor including the configuration of a surface and the position of its natural and man-made features; and detailed nautical charts are fundamental for many sciences such as physical oceanography, biology and marine geology. The hydrographic offices, which use the Multi Beam Echo sounder (MBE) system for the establishment of nautical charts, have their own set of accuracy standards for hydrographic surveys, which generally comply with the standards defined by the International Hydrographic Organization. MBE systems include multiple measurement systems such as sonar head, positioning system, motion sensor that work in a synchronized manner. Before the measurements, the "Patch Test" is required to eliminate the systematic errors due to instrumental synchronization and installation. In this test, signal delay test (latency), Y-axis rotation (roll), X-axis rotation (pitch), Z-axis rotation (yaw) errors are calculated. Besides, the effects of the sound velocity measurement through water column and the sea level changes need to be taken into consideration especially in the multi-temporal data analysis and 3D modeling. In this paper, the seafloor of the Anamur -TRNC Drinking Water Pipeline route in the "Northern Cyprus Water Project" is selected as a study area. This project, a unique in the world, is an international water diversion project designed to supply water for drinking and irrigation from southern Turkey to Northern Cyprus via pipeline under Mediterranean Sea. Multi temporal multi beam echo sounder measurements are used in the change analysis and surface modeling and the efficiency of this system is outlined together with its limitations.

  15. Effects of high-heeled footwear on static and dynamic pelvis position and lumbar lordosis in experienced younger and middle-aged women.

    Science.gov (United States)

    Schroeder, Jan; Hollander, Karsten

    2018-01-01

    There is still conflicting evidence about the effect of high-heeled footwear on posture, especially if methodological confounders are taken into account. The purpose of this study was to investigate the effect of high-heeled footwear on lumbopelvic parameters in experienced younger and middle-aged women while standing and walking. Thirty-seven experienced younger (n=19:18-25 years) and middle-aged (n=18:26-56 years) women were included in this randomized crossover study. Using a non-invasive back shape reconstruction device (rasterstereography), static (pelvic tilt and lumbar lordosis angle) and dynamic (pelvic rotation, median lumbar lordosis angle and range of motion) parameters representing pelvis position and lumbar curvature were measured. In order to analyse standing and walking on a treadmill (0.83m/s), the effects of high-heels (7-11cm) were compared to standard control shoes. There were no effects on the lumbar lordosis angle or range of motion under static or dynamic conditions (p>0.05, d≤0.06). But there was a small effect for a reduced pelvic tilt (p=0.003, d=0.24) and a moderate effect for an increased transversal pelvic rotation (p=0.001, d=0.63) due to high heel shoed standing or walking, respectively. There were no significant age-group or interaction effects (p>0.05). Altered pelvic parameters may be interpreted as compensatory adaptations to high-heeled footwear rather than lumbar lordosis adaptations in experienced wearers. The impact of these findings on back complaints should be revisited carefully, because muscular overuse as well as postural load relieving may contribute to chronic consequences. Further research is necessary to examine clinically relevant outcomes corresponding to postural alterations. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Recent advances in engineering topography mediated antibacterial surfaces

    Science.gov (United States)

    Hasan, Jafar; Chatterjee, Kaushik

    2015-09-01

    The tendency of bacterial cells to adhere and colonize a material surface leading to biofilm formation is a fundamental challenge underlying many different applications including microbial infections associated with biomedical devices and products. Although, bacterial attachment to surfaces has been extensively studied in the past, the effect of surface topography on bacteria-material interactions has received little attention until more recently. We review the recent progress in surface topography based approaches for engineering antibacterial surfaces. Biomimicry of antibacterial surfaces in nature is a popular strategy. Whereas earlier endeavors in the field aimed at minimizing cell attachment, more recent efforts have focused on developing bactericidal surfaces. However, not all such topography mediated bactericidal surfaces are necessarily cytocompatible thus underscoring the need for continued efforts for research in this area for developing antibacterial and yet cytocompatible surfaces for use in implantable biomedical applications. This mini-review provides a brief overview of the current strategies and challenges in the emerging field of topography mediated antibacterial surfaces.

  17. Role of Cigarette Sensory Cues in Modifying Puffing Topography

    Science.gov (United States)

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

    2012-01-01

    Background Human puffing topography promotes tobacco dependence by ensuring nicotine delivery, but the factors that determine puffing behavior are not well explained by existing models. Chemosensory cues generated by variations in cigarette product design features may serve as conditioned cues to allow the smoker to optimize nicotine delivery by adjusting puffing topography. Internal tobacco industry research documents were reviewed to understand the influence of sensory cues on puffing topography, and to examine how the tobacco industry has designed cigarettes, including modified risk tobacco products (MRTPs), to enhance puffing behavior to optimize nicotine delivery and product acceptability. Methods Relevant internal tobacco industry documents were identified using systematic searching with key search terms and phrases, and then snowball sampling method was applied to establish further search terms. Results Modern cigarettes are designed by cigarette manufacturers to provide sensory characteristics that not only maintain appeal, but provide cues which inform puffing intensity. Alterations in the chemosensory cues provided in tobacco smoke play an important role in modifying smoking behavior independently of the central effects of nicotine. Conclusions An associative learning model is proposed to explain the influence of chemosensory cues on variation in puffing topography. These cues are delivered via tobacco smoke and are moderated by design features and additives used in cigarettes. The implications for regulation of design features of modified risk tobacco products, which may act to promote intensive puffing while lowering risk perceptions, are discussed. PMID:22365895

  18. Influence of substrate topography on cathodic delamination of anticorrosive coatings

    DEFF Research Database (Denmark)

    Sørensen, Per Aggerholm; Kiil, Søren; Dam-Johansen, Kim

    2009-01-01

    and thereby the substrate topography, whereas the coating thickness had little influence. The presence of a significant potential gradient between the anode and the cathode and the dependency of the delamination rate on the tortuosity of the steel surface suggests that cathodic delamination is controlled...

  19. The Space-Time Topography of English Speakers

    Science.gov (United States)

    Duman, Steve

    2016-01-01

    English speakers talk and think about Time in terms of physical space. The past is behind us, and the future is in front of us. In this way, we "map" space onto Time. This dissertation addresses the specificity of this physical space, or its topography. Inspired by languages like Yupno (Nunez, et al., 2012) and Bamileke-Dschang (Hyman,…

  20. Nanotubular topography enhances the bioactivity of titanium implants.

    Science.gov (United States)

    Huang, Jingyan; Zhang, Xinchun; Yan, Wangxiang; Chen, Zhipei; Shuai, Xintao; Wang, Anxun; Wang, Yan

    2017-08-01

    Surface modification on titanium implants plays an important role in promoting mesenchymal stem cell (MSC) response to enhance osseointegration persistently. In this study, nano-scale TiO 2 nanotube topography (TNT), micro-scale sand blasted-acid etched topography (SLA), and hybrid sand blasted-acid etched/nanotube topography (SLA/TNT) were fabricated on the surfaces of titanium implants. Although the initial cell adherence at 60 min among TNT, SLA and TNT/SLA was not different, SLA and SLA/TNT presented to be rougher and suppressed the proliferation of MSC. TNT showed hydrophilic surface and balanced promotion of cellular functions. After being implanted in rabbit femur models, TNT displayed the best osteogenesis inducing ability as well as strong bonding strength to the substrate. These results indicate that nano-scale TNT provides favorable surface topography for improving the clinical performance of endosseous implants compared with micro and hybrid micro/nano surfaces, suggesting a promising and reliable surface modification strategy of titanium implants for clinical application. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Does Dry Eye Affect Repeatability of Corneal Topography Measurements?

    Science.gov (United States)

    Doğan, Aysun Şanal; Gürdal, Canan; Köylü, Mehmet Talay

    2018-04-01

    The purpose of this study was to assess the repeatability of corneal topography measurements in dry eye patients and healthy controls. Participants underwent consecutive corneal topography measurements (Sirius; Costruzione Strumenti Oftalmici, Florence, Italy). Two images with acquisition quality higher than 90% were accepted. The following parameters were evaluated: minimum and central corneal thickness, aqueous depth, apex curvature, anterior chamber volume, horizontal anterior chamber diameter, iridocorneal angle, cornea volume, and average simulated keratometry. Repeatability was assessed by calculating intra-class correlation coefficient. Thirty-three patients with dry eye syndrome and 40 healthy controls were enrolled to the study. The groups were similar in terms of age (39 [18-65] vs. 30.5 [18-65] years, p=0.198) and gender (M/F: 4/29 vs. 8/32, p=0.366). Intra-class correlation coefficients among all topography parameters within both groups showed excellent repeatability (>0.90). The anterior segment measurements provided by the Sirius corneal topography system were highly repeatable for dry eye patients and are sufficiently reliable for clinical practice and research.

  2. Percolation, statistical topography, and transport in random media

    International Nuclear Information System (INIS)

    Isichenko, M.B.

    1992-01-01

    A review of classical percolation theory is presented, with an emphasis on novel applications to statistical topography, turbulent diffusion, and heterogeneous media. Statistical topography involves the geometrical properties of the isosets (contour lines or surfaces) of a random potential ψ(x). For rapidly decaying correlations of ψ, the isopotentials fall into the same universality class as the perimeters of percolation clusters. The topography of long-range correlated potentials involves many length scales and is associated either with the correlated percolation problem or with Mandelbrot's fractional Brownian reliefs. In all cases, the concept of fractal dimension is particularly fruitful in characterizing the geometry of random fields. The physical applications of statistical topography include diffusion in random velocity fields, heat and particle transport in turbulent plasmas, quantum Hall effect, magnetoresistance in inhomogeneous conductors with the classical Hall effect, and many others where random isopotentials are relevant. A geometrical approach to studying transport in random media, which captures essential qualitative features of the described phenomena, is advocated

  3. The Effect of Substrate Topography on Coating Cathodic Delamination

    DEFF Research Database (Denmark)

    Erik Weinell, Claus; Sørensen, Per A.; Kiil, Søren

    2011-01-01

    This article describes the effect of steel substrate topography on coating cathodic delamination. The study showed that the surface preparation can be used to control and minimize the rate of cathodic delamination. The coating should have maximum wetting properties so that substrates with high...

  4. How to handle topography in practical geoid determination: three examples

    DEFF Research Database (Denmark)

    Omang, O.C.D.; Forsberg, René

    2000-01-01

    Three different methods of handling topography in geoid determination were investigated. The first two methods employ the residual terrain model (RTM) remove-restore technique, yielding the quasi-geoid, whereas the third method uses the classical Helmert condensation method, yielding the geoid. All...

  5. Payload topography camera of Chang'e-3

    International Nuclear Information System (INIS)

    Yu, Guo-Bin; Liu, En-Hai; Zhao, Ru-Jin; Zhong, Jie; Zhou, Xiang-Dong; Zhou, Wu-Lin; Wang, Jin; Chen, Yuan-Pei; Hao, Yong-Jie

    2015-01-01

    Chang'e-3 was China's first soft-landing lunar probe that achieved a successful roving exploration on the Moon. A topography camera functioning as the lander's “eye” was one of the main scientific payloads installed on the lander. It was composed of a camera probe, an electronic component that performed image compression, and a cable assembly. Its exploration mission was to obtain optical images of the lunar topography in the landing zone for investigation and research. It also observed rover movement on the lunar surface and finished taking pictures of the lander and rover. After starting up successfully, the topography camera obtained static images and video of rover movement from different directions, 360° panoramic pictures of the lunar surface around the lander from multiple angles, and numerous pictures of the Earth. All images of the rover, lunar surface, and the Earth were clear, and those of the Chinese national flag were recorded in true color. This paper describes the exploration mission, system design, working principle, quality assessment of image compression, and color correction of the topography camera. Finally, test results from the lunar surface are provided to serve as a reference for scientific data processing and application. (paper)

  6. Experiments in the topography station of the Daresbury Laboratory

    International Nuclear Information System (INIS)

    Machado, W.G.

    1983-01-01

    A comparison is made of the contrast in topographies by diffraction, produced by synchrotron radiation and by copper and molybdenum characteristic radiations conventionally generated. Some experiments in the study of diamond geminated crystals and the photoluminescence of several crystalline specimens by synchrotron radiation are related. (L.C.) [pt

  7. Fabrication of cell container arrays with overlaid surface topographies.

    NARCIS (Netherlands)

    Truckenmuller, R.; Giselbrecht, S.; Escalante-Marun, M.; Groenendijk, M.; Papenburg, B.; Rivron, N.; Unadkat, H.; Saile, V.; Subramaniam, V.; Berg, A. van den; Blitterswijk, C. Van; Wessling, M.; Boer, J. den; Stamatialis, D.

    2012-01-01

    This paper presents cell culture substrates in the form of microcontainer arrays with overlaid surface topographies, and a technology for their fabrication. The new fabrication technology is based on microscale thermoforming of thin polymer films whose surfaces are topographically prepatterned on a

  8. Fabrication of cell container arrays with overlaid surface topographies

    NARCIS (Netherlands)

    Truckenmüller, Roman; Giselbrecht, Stefan; Escalante-Marun, Maryana; Groenendijk, Max; Papenburg, Bernke; Rivron, Nicolas; Unadkat, Hemant; Saile, Volker; Subramaniam, Vinod; van den Berg, Albert; van Blitterswijk, Clemens; Wessling, Matthias; Boer, Jan de; Stamatialis, Dimitrios

    This paper presents cell culture substrates in the form of microcontainer arrays with overlaid surface topographies, and a technology for their fabrication. The new fabrication technology is based on microscale thermoforming of thin polymer films whose surfaces are topographically prepatterned on a

  9. Topography and distribution of ostia venae hepatica in the ...

    African Journals Online (AJOL)

    BACKGROUND: Openings of hepatic veins into the retrohepatic surface of the inferior vena cava. (ostia venae hepatica) play a part in controlling hepatic circulation by acting as collateral channels in obstruction. Their topography and distribution must be taken into account during catheterization and liver transplantation.

  10. Does Dry Eye Affect Repeatability of Corneal Topography Measurements?

    Directory of Open Access Journals (Sweden)

    Aysun Şanal Doğan

    2018-04-01

    Full Text Available Objectives: The purpose of this study was to assess the repeatability of corneal topography measurements in dry eye patients and healthy controls. Materials and Methods: Participants underwent consecutive corneal topography measurements (Sirius; Costruzione Strumenti Oftalmici, Florence, Italy. Two images with acquisition quality higher than 90% were accepted. The following parameters were evaluated: minimum and central corneal thickness, aqueous depth, apex curvature, anterior chamber volume, horizontal anterior chamber diameter, iridocorneal angle, cornea volume, and average simulated keratometry. Repeatability was assessed by calculating intra-class correlation coefficient. Results: Thirty-three patients with dry eye syndrome and 40 healthy controls were enrolled to the study. The groups were similar in terms of age (39 [18-65] vs. 30.5 [18-65] years, p=0.198 and gender (M/F: 4/29 vs. 8/32, p=0.366. Intra-class correlation coefficients among all topography parameters within both groups showed excellent repeatability (>0.90. Conclusion: The anterior segment measurements provided by the Sirius corneal topography system were highly repeatable for dry eye patients and are sufficiently reliable for clinical practice and research.

  11. The geostrophic velocity field in shallow water over topography

    Science.gov (United States)

    Charnock, Henry; Killworth, Peter D.

    1998-01-01

    A recent note (Hopkins, T.S., 1996. A note on the geostrophic velocity field referenced to a point. Continental Shelf Research 16, 1621-1630) suggests a method for evaluating absolute pressure gradients in stratified water over topography. We demonstrate that this method requires no along-slope bottom velocity, in contradiction to what is usually observed, and that mass is not conserved.

  12. Characterization of Mo/Si multilayer growth on stepped topographies

    NARCIS (Netherlands)

    van den Boogaard, Toine; Louis, Eric; Zoethout, E.; Goldberg, K.A.; Bijkerk, Frederik

    2011-01-01

    Mo/Si multilayer mirrors with nanoscale bilayer thicknesses have been deposited on stepped substrate topographies, using various deposition angles. The multilayer morphology at the step-edge region was studied by cross section transmission electron microscopy. A transition from a continuous- to

  13. [Influence of different surface treatments on porcelain surface topography].

    Science.gov (United States)

    Tai, Yinxia; Zhu, Xianchun; Sen, Yan; Liu, Chang; Zhang, Xian; Shi, Xueming

    2013-02-01

    To evaluate the influence of different surface treatments on porcelain surface topography. Metal ceramic prostheses in 6 groups were treated according to the different surface treatment methods, and the surface topography was observed through scanning electron microscope (SEM). Group A was the control one (untreated), group B was etched by 9.6% hydrofluoric acid(HF), group C was deglazed by grinding and then etched by 9.6% HF, group D was treated with Nd: YAG laser irradiation(0.75 W) and HF etching, group E was treated with Nd: YAG laser irradiation (1.05 W) and HF etching, and group F was treated with laser irradiation (1.45 W) and HF etching. Surface topography was different in different groups. A lot of inerratic cracks with the shapes of rhombuses and grid, and crater with a shape of circle were observed on the ceramic surface after treatment with energy parameters of 1.05 W Nd: YAG laser irradiation and 9.6% HF etching (group E). Surface topography showed a lot of concaves on the inner wall of the cracks, and the concaves with diameter of 1-5 microm could be observed on the inner wall of the holes, which had a diameter of 20 microm under SEM. The use of Nd: YAG laser irradiation with the energy parameters of 1.05 W and the HF with a concentration of 9.6% can evenly coarsen the porcelain surface, that is an effective surface treatment method.

  14. EAARL topography-Potato Creek watershed, Georgia, 2010

    Science.gov (United States)

    Bonisteel-Cormier, J.M.; Nayegandhi, Amar; Fredericks, Xan; Jones, J.W.; Wright, C.W.; Brock, J.C.; Nagle, D.B.

    2011-01-01

    This DVD contains lidar-derived first-surface (FS) and bare-earth (BE) topography GIS datasets of a portion of the Potato Creek watershed in the Apalachicola-Chattahoochee-Flint River basin, Georgia. These datasets were acquired on February 27, 2010.

  15. Stress distribution and topography of Tellus Regio, Venus

    Science.gov (United States)

    Williams, David R.; Greeley, Ronald

    1989-01-01

    The Tellus Regio area of Venus represents a subset of a narrow latitude band where Pioneer Venus Orbiter (PVO) altimetry data, line-of-sight (LOS) gravity data, and Venera 15/16 radar images have all been obtained with good resolution. Tellus Regio also has a wide variety of surface morphologic features, elevations ranging up to 2.5 km, and a relatively low LOS gravity anomaly. This area was therefore chosen in order to examine the theoretical stress distributions resulting from various models of compensation of the observed topography. These surface stress distributions are then compared with the surface morphology revealed in the Venera 15/16 radar images. Conclusions drawn from these comparisons will enable constraints to be put on various tectonic parameters relevant to Tellus Regio. The stress distribution is calculated as a function of the topography, the equipotential anomaly, and the assumed model parameters. The topography data is obtained from the PVO altimetry. The equipotential anomaly is estimated from the PVO LOS gravity data. The PVO LOS gravity represents the spacecraft accelerations due to mass anomalies within the planet. These accelerations are measured at various altitudes and angles to the local vertical and therefore do not lend themselves to a straightforward conversion. A minimum variance estimator of the LOS gravity data is calculated, taking into account the various spacecraft altitudes and LOS angles and using the measured PVO topography as an a priori constraint. This results in an estimated equivalent surface mass distribution, from which the equipotential anomaly is determined.

  16. Stress distribution and topography of Tellus Regio, Venus

    International Nuclear Information System (INIS)

    Williams, D.R.; Greeley, R.

    1989-01-01

    The Tellus Regio area of Venus represents a subset of a narrow latitude band where Pioneer Venus Orbiter (PVO) altimetry data, line-of-sight (LOS) gravity data, and Venera 15/16 radar images have all been obtained with good resolution. Tellus Regio also has a wide variety of surface morphologic features, elevations ranging up to 2.5 km, and a relatively low LOS gravity anomaly. This area was therefore chosen in order to examine the theoretical stress distributions resulting from various models of compensation of the observed topography. These surface stress distributions are then compared with the surface morphology revealed in the Venera 15/16 radar images. Conclusions drawn from these comparisons will enable constraints to be put on various tectonic parameters relevant to Tellus Regio. The stress distribution is calculated as a function of the topography, the equipotential anomaly, and the assumed model parameters. The topography data is obtained from the PVO altimetry. The equipotential anomaly is estimated from the PVO LOS gravity data. The PVO LOS gravity represents the spacecraft accelerations due to mass anomalies within the planet. These accelerations are measured at various altitudes and angles to the local vertical and therefore do not lend themselves to a straightforward conversion. A minimum variance estimator of the LOS gravity data is calculated, taking into account the various spacecraft altitudes and LOS angles and using the measured PVO topography as an a priori constraint. This results in an estimated equivalent surface mass distribution, from which the equipotential anomaly is determined

  17. 175 Years of Linear Programming - Minimax and Cake Topography

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 4; Issue 7. 175 Years of Linear Programming - Minimax and Cake Topography. Vijay Chandru M R Rao. Series Article Volume 4 Issue 7 July 1999 pp 4-13. Fulltext. Click here to view fulltext PDF. Permanent link:

  18. An anatomical and functional topography of human auditory cortical areas

    Directory of Open Access Journals (Sweden)

    Michelle eMoerel

    2014-07-01

    Full Text Available While advances in magnetic resonance imaging (MRI throughout the last decades have enabled the detailed anatomical and functional inspection of the human brain non-invasively, to date there is no consensus regarding the precise subdivision and topography of the areas forming the human auditory cortex. Here, we propose a topography of the human auditory areas based on insights on the anatomical and functional properties of human auditory areas as revealed by studies of cyto- and myelo-architecture and fMRI investigations at ultra-high magnetic field (7 Tesla. Importantly, we illustrate that - whereas a group-based approach to analyze functional (tonotopic maps is appropriate to highlight the main tonotopic axis - the examination of tonotopic maps at single subject level is required to detail the topography of primary and non-primary areas that may be more variable across subjects. Furthermore, we show that considering multiple maps indicative of anatomical (i.e. myelination as well as of functional properties (e.g. broadness of frequency tuning is helpful in identifying auditory cortical areas in individual human brains. We propose and discuss a topography of areas that is consistent with old and recent anatomical post mortem characterizations of the human auditory cortex and that may serve as a working model for neuroscience studies of auditory functions.

  19. Allometric scaling of infraorbital surface topography in Homo.

    Science.gov (United States)

    Maddux, Scott D; Franciscus, Robert G

    2009-02-01

    Infraorbital morphology is often included in phylogenetic and functional analyses of Homo. The inclusion of distinct infraorbital configurations, such as the "canine fossa" in Homo sapiens or the "inflated" maxilla in Neandertals, is generally based on either descriptive or qualitative assessments of this morphology, or simple linear chord and subtense measurements. However, the complex curvilinear surface of the infraorbital region has proven difficult to quantify through these traditional methods. In this study, we assess infraorbital shape and its potential allometric scaling in fossil Homo (n=18) and recent humans (n=110) with a geometric morphometric method well-suited for quantifying complex surface topographies. Our results indicate that important aspects of infraorbital shape are correlated with overall infraorbital size across Homo. Specifically, individuals with larger infraorbital areas tend to exhibit relatively flatter infraorbital surface topographies, taller and narrower infraorbital areas, sloped inferior orbital rims, anteroinferiorly oriented maxillary body facies, posteroinferiorly oriented maxillary processes of the zygomatic, and non-everted lateral nasal margins. In contrast, individuals with smaller infraorbital regions generally exhibit relatively depressed surface topographies, shorter and wider infraorbital areas, projecting inferior orbital rims, posteroinferiorly oriented maxillary body facies, anteroinferiorly oriented maxillary processes, and everted lateral nasal margins. These contrasts form a continuum and only appear dichotomized at the ends of the infraorbital size spectrum. In light of these results, we question the utility of incorporating traditionally polarized infraorbital morphologies in phylogenetic and functional analyses without due consideration of continuous infraorbital and facial size variation in Homo. We conclude that the essentially flat infraorbital surface topography of Neandertals is not unique and can be

  20. Time-Resolved Quantitative Analysis of the Diaphragms During Tidal Breathing in a Standing Position Using Dynamic Chest Radiography with a Flat Panel Detector System ("Dynamic X-Ray Phrenicography"): Initial Experience in 172 Volunteers.

    Science.gov (United States)

    Yamada, Yoshitake; Ueyama, Masako; Abe, Takehiko; Araki, Tetsuro; Abe, Takayuki; Nishino, Mizuki; Jinzaki, Masahiro; Hatabu, Hiroto; Kudoh, Shoji

    2017-04-01

    Diaphragmatic motion in a standing position during tidal breathing remains unclear. The purpose of this observational study was to evaluate diaphragmatic motion during tidal breathing in a standing position in a health screening center cohort using dynamic chest radiography in association with participants' demographic characteristics. One hundred seventy-two subjects (103 men; aged 56.3 ± 9.8 years) underwent sequential chest radiographs during tidal breathing using dynamic chest radiography with a flat panel detector system. We evaluated the excursions of and peak motion speeds of the diaphragms. Associations between the excursions and participants' demographics (gender, height, weight, body mass index [BMI], smoking history, tidal volume, vital capacity, and forced expiratory volume) were investigated. The average excursion of the left diaphragm (14.9 ± 4.6 mm, 95% CI 14.2-15.5 mm) was significantly larger than that of the right (11.0 ± 4.0 mm, 95% CI 10.4-11.6 mm) (P <0.001). The peak motion speed of the left diaphragm (inspiratory, 16.6 ± 4.2 mm/s; expiratory, 13.7 ± 4.2 mm/s) was significantly faster than that of the right (inspiratory, 12.4 ± 4.4 mm/s; expiratory, 9.4 ± 3.8 mm/s) (both P <0.001). Both simple and multiple regression models demonstrated that higher BMI and higher tidal volume were associated with increased excursions of the bilateral diaphragm (all P <0.05). The average excursions of the diaphragms are 11.0 mm (right) and 14.9 mm (left) during tidal breathing in a standing position. The diaphragmatic motion of the left is significantly larger and faster than that of the right. Higher BMI and tidal volume are associated with increased excursions of the bilateral diaphragm. Copyright © 2017 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

  1. Dynamic Capabilities

    DEFF Research Database (Denmark)

    Grünbaum, Niels Nolsøe; Stenger, Marianne

    2013-01-01

    The findings reveal a positive relationship between dynamic capabilities and innovation performance in the case enterprises, as we would expect. It was, however, not possible to establish a positive relationship between innovation performance and profitability. Nor was there any positive...... relationship between dynamic capabilities and profitability....

  2. Insights into secondary growth in perennial plants: its unequal spatial and temporal dynamics in the apple (Malus domestica) is driven by architectural position and fruit load.

    Science.gov (United States)

    Lauri, P E; Kelner, J J; Trottier, C; Costes, E

    2010-04-01

    Secondary growth is a main physiological sink. However, the hierarchy between the processes which compete with secondary growth is still a matter of debate, especially on fruit trees where fruit weight dramatically increases with time. It was hypothesized that tree architecture, here mediated by branch age, is likely to have a major effect on the dynamics of secondary growth within a growing season. Three variables were monitored on 6-year-old 'Golden Delicious' apple trees from flowering time to harvest: primary shoot growth, fruit volume, and cross-section area of branch portions of consecutive ages. Analyses were done through an ANOVA-type analysis in a linear mixed model framework. Secondary growth exhibited three consecutive phases characterized by unequal relative area increment over the season. The age of the branch had the strongest effect, with the highest and lowest relative area increment for the current-year shoots and the trunk, respectively. The growth phase had a lower effect, with a shift of secondary growth through the season from leafy shoots towards older branch portions. Eventually, fruit load had an effect on secondary growth mainly after primary growth had ceased. The results support the idea that relationships between production of photosynthates and allocation depend on both primary growth and branch architectural position. Fruit load mainly interacted with secondary growth later in the season, especially on old branch portions.

  3. CryoSat Data Quality, Product Evolutions and Activities in Support to the Sentinel-3 Topography Mission

    Science.gov (United States)

    Bouffard, J.; Femenias, P.; Parrinello, T.; Bojkov, B.; Dinardo, S.; Fornari, M.; Benveniste, J.

    2015-12-01

    It is well known that conventional nadir altimetry acquisitions are not always suitable to monitor oceanic small-scale dynamics, coastal processes as well as ice sheet areas of rough topography. CryoSat (CS) is the first SAR(in) altimeter concept to be flown on Earth and therefore represents a unique opportunity to process SAR data for which we still have poor knowledge. After briefly presenting the CS data quality and recent evolutions, this paper provide a high level overview of CS activities specifically aiming at supporting the Copernicus Sentinel-3 Topography mission (S-3) within the framework of: - The ground segment processing development and evolution - The data validation and quality control - The potential synergies for future scientific and operational exploitation over ice and ocean.

  4. Understanding how surface chemistry and topography enhance fog harvesting based on the superwetting surface with patterned hemispherical bulges.

    Science.gov (United States)

    Zhong, Lieshuang; Zhu, Hai; Wu, Yang; Guo, Zhiguang

    2018-09-01

    The Namib Desert beetle-Stenocara can adapt to the arid environment by its fog harvesting ability. A series of samples with different topography and wettability that mimicked the elytra of the beetle were fabricated to study the effect of these factors on fog harvesting. The superhydrophobic bulgy sample harvested 1.5 times the amount of water than the sample with combinational pattern of hydrophilic bulgy/superhydrophobic surrounding and 2.83 times than the superhydrophobic surface without bulge. These bulges focused the droplets around them which endowed droplets with higher velocity and induced the highest dynamic pressure atop them. Superhydrophobicity was beneficial for the departure of harvested water on the surface of sample. The bulgy topography, together with surface wettability, dominated the process of water supply and water removal. Copyright © 2018 Elsevier Inc. All rights reserved.

  5. BedMachine v3: Complete Bed Topography and Ocean Bathymetry Mapping of Greenland From Multibeam Echo Sounding Combined With Mass Conservation

    DEFF Research Database (Denmark)

    Morlighem, M.; Williams, C. N.; Rignot, E.

    2017-01-01

    Greenland's bed topography is a primary control on ice flow, grounding line migration, calving dynamics, and subglacial drainage. Moreover, fjord bathymetry regulates the penetration of warm Atlantic water (AW) that rapidly melts and undercuts Greenland's marine‐terminating glaciers. Here we...... present a new compilation of Greenland bed topography that assimilates seafloor bathymetry and ice thickness data through a mass conservation approach. A new 150 m horizontal resolution bed topography/bathymetric map of Greenland is constructed with seamless transitions at the ice/ocean interface......, yielding major improvements over previous data sets, particularly in the marine‐terminating sectors of northwest and southeast Greenland. Our map reveals that the total sea level potential of the Greenland ice sheet is 7.42 ± 0.05 m, which is 7 cm greater than previous estimates. Furthermore, it explains...

  6. The effect of topography on the evolution of unstable disturbances in a baroclinic atmosphere

    Science.gov (United States)

    Clark, J. H. E.

    1985-01-01

    A two layer spectral quasi-geostrophic model is used to simulate the effects of topography on the equilibria, their stability, and the long term evolution of incipient unstable waves. The flow is forced by latitudinally dependent radiative heating. Dissipation is in the form of Rayleigh friction. An analytical solution is found for the propagating finite amplitude waves which result from baroclinic instability of the zonal winds when topography is absent. The appearance of this solution for wavelengths just longer than the Rossby radius of deformation and disappearance of ultra-long wavelengths is interpreted in terms of the Hopf bifurcation theory. Simple dynamic and thermodynamic criteria for the existence of periodic Rossby solutions are presented. A Floquet stability analysis shows that the waves are neutral. The nature of the form drag instability of high index equilibria is investigated. The proximity of the equilibrium shear to a resonant value is essential for the instability, provided the equilibrium occurs at a slightly stronger shear than resonance.

  7. Multi-source least-squares reverse time migration with topography

    KAUST Repository

    Zhang, Dongliang; Schuster, Gerard T.; Zhan, Ge

    2013-01-01

    We demonstrate an accurate method for calculating LSM images from data recorded on irregular topography. Our results with both the Marmousi and Foothill models with steep topography suggest the effectiveness of this method.

  8. Multi-source least-squares reverse time migration with topography

    KAUST Repository

    Zhang, Dongliang

    2013-09-22

    We demonstrate an accurate method for calculating LSM images from data recorded on irregular topography. Our results with both the Marmousi and Foothill models with steep topography suggest the effectiveness of this method.

  9. 3D topography measurements on correlation cells—a new approach to forensic ballistics identifications

    International Nuclear Information System (INIS)

    Song, John; Chu, Wei; Tong, Mingsi; Soons, Johannes

    2014-01-01

    Based on three-dimensional (3D) topography measurements on correlation cells, the National Institute of Standards and Technology (NIST) has developed the ‘NIST Ballistics Identification System (NBIS)’ aimed at accurate ballistics identifications and fast ballistics evidence searches. The 3D topographies are divided into arrays of correlation cells to identify ‘valid correlation areas’ and eliminate ‘invalid correlation areas’ from the matching and identification procedure. A ‘congruent matching cells’ (CMC)’ method using three types of identification parameters of the paired correlation cells (cross correlation function maximum CCF max , spatial registration position in x–y and registration angle θ) is used for high accuracy ballistics identifications. ‘Synchronous processing’ is proposed for correlating multiple cell pairs at the same time to increase the correlation speed. The proposed NBIS can be used for correlations of both geometrical topographies and optical intensity images. All the correlation parameters and algorithms are in the public domain and subject to open tests. An error rate reporting procedure has been developed that can greatly add to the scientific support for the firearm and toolmark identification specialty, and give confidence to the trier of fact in court proceedings. The NBIS is engineered to employ transparent identification parameters and criteria, statistical models and correlation algorithms. In this way, interoperability between different ballistics identification systems can be more easily achieved. This interoperability will make the NBIS suitable for ballistics identifications and evidence searches with large national databases, such as the National Integrated Ballistic Information Network in the United States. (paper)

  10. Dysconnection topography in schizophrenia revealed with state-space analysis of EEG.

    Science.gov (United States)

    Jalili, Mahdi; Lavoie, Suzie; Deppen, Patricia; Meuli, Reto; Do, Kim Q; Cuénod, Michel; Hasler, Martin; De Feo, Oscar; Knyazeva, Maria G

    2007-10-24

    The dysconnection hypothesis has been proposed to account for pathophysiological mechanisms underlying schizophrenia. Widespread structural changes suggesting abnormal connectivity in schizophrenia have been imaged. A functional counterpart of the structural maps would be the EEG synchronization maps. However, due to the limits of currently used bivariate methods, functional correlates of dysconnection are limited to the isolated measurements of synchronization between preselected pairs of EEG signals. To reveal a whole-head synchronization topography in schizophrenia, we applied a new method of multivariate synchronization analysis called S-estimator to the resting dense-array (128 channels) EEG obtained from 14 patients and 14 controls. This method determines synchronization from the embedding dimension in a state-space domain based on the theoretical consequence of the cooperative behavior of simultaneous time series-the shrinking of the state-space embedding dimension. The S-estimator imaging revealed a specific synchronization landscape in schizophrenia patients. Its main features included bilaterally increased synchronization over temporal brain regions and decreased synchronization over the postcentral/parietal region neighboring the midline. The synchronization topography was stable over the course of several months and correlated with the severity of schizophrenia symptoms. In particular, direct correlations linked positive, negative, and general psychopathological symptoms to the hyper-synchronized temporal clusters over both hemispheres. Along with these correlations, general psychopathological symptoms inversely correlated within the hypo-synchronized postcentral midline region. While being similar to the structural maps of cortical changes in schizophrenia, the S-maps go beyond the topography limits, demonstrating a novel aspect of the abnormalities of functional cooperation: namely, regionally reduced or enhanced connectivity. The new method of

  11. Dysconnection topography in schizophrenia revealed with state-space analysis of EEG.

    Directory of Open Access Journals (Sweden)

    Mahdi Jalili

    2007-10-01

    Full Text Available The dysconnection hypothesis has been proposed to account for pathophysiological mechanisms underlying schizophrenia. Widespread structural changes suggesting abnormal connectivity in schizophrenia have been imaged. A functional counterpart of the structural maps would be the EEG synchronization maps. However, due to the limits of currently used bivariate methods, functional correlates of dysconnection are limited to the isolated measurements of synchronization between preselected pairs of EEG signals.To reveal a whole-head synchronization topography in schizophrenia, we applied a new method of multivariate synchronization analysis called S-estimator to the resting dense-array (128 channels EEG obtained from 14 patients and 14 controls. This method determines synchronization from the embedding dimension in a state-space domain based on the theoretical consequence of the cooperative behavior of simultaneous time series-the shrinking of the state-space embedding dimension. The S-estimator imaging revealed a specific synchronization landscape in schizophrenia patients. Its main features included bilaterally increased synchronization over temporal brain regions and decreased synchronization over the postcentral/parietal region neighboring the midline. The synchronization topography was stable over the course of several months and correlated with the severity of schizophrenia symptoms. In particular, direct correlations linked positive, negative, and general psychopathological symptoms to the hyper-synchronized temporal clusters over both hemispheres. Along with these correlations, general psychopathological symptoms inversely correlated within the hypo-synchronized postcentral midline region. While being similar to the structural maps of cortical changes in schizophrenia, the S-maps go beyond the topography limits, demonstrating a novel aspect of the abnormalities of functional cooperation: namely, regionally reduced or enhanced connectivity.The new

  12. Biomechanical properties of jaw periosteum-derived mineralized culture on different titanium topography.

    Science.gov (United States)

    Att, Wael; Kubo, Katsutoshi; Yamada, Masahiro; Maeda, Hatsuhiko; Ogawa, Takahiro

    2009-01-01

    This study evaluated the biomechanical properties of periosteum-derived mineralized culture on different surface topographies of titanium. Titanium surfaces modified by machining or by acid etching were analyzed using scanning electron microscopy (SEM). Rat mandibular periosteum-derived cells were cultured on either of the titanium surfaces. Cell proliferation was evaluated by cell counts, and gene expression was analyzed using a reverse-transcriptase polymerase chain reaction. Alkaline phosphatase (ALP) stain assay was employed to evaluate osteoblastic activity. Matrix mineralization was examined via von Kossa stain assay, total calcium deposition, and SEM. The hardness and elastic modulus of mineralized cultures were measured using a nano-indenter. The machined surface demonstrated a flat topographic configuration, while the acid-etched surface revealed a uniform micron-scale roughness. Both cell density and ALP activity were significantly higher on the machined surface than on the acid-etched surface. The expression of bone-related genes was up-regulated or enhanced on the acid-etched surface compared to the machined surface. Von Kossa stain showed significantly greater positive areas for the machined surface compared to the acid-etched surface, while total calcium deposition was statistically similar. Mineralized culture on the acid-etched surface was characterized by denser calcium deposition, more mature collagen deposition on the superficial layer, and larger and denser globular matrices inside the matrix than the culture on the machined surface. The mineralized matrix on the acid-etched surface was two times harder than on the machined surface, whereas the elastic modulus was comparable between the two surfaces. The design of this study can be used as a model to evaluate the effect of implant surface topography on the biomechanical properties of periosteum-derived mineralized culture. The results suggest that mandibular periosteal cells respond to different

  13. Rapid-Response or Repeat-Mode Topography from Aerial Structure from Motion

    Science.gov (United States)

    Nissen, E.; Johnson, K. L.; Fitzgerald, F. S.; Morgan, M.; White, J.

    2014-12-01

    This decade has seen a surge of interest in Structure-from-Motion (SfM) as a means of generating high-resolution topography and coregistered texture maps from stereo digital photographs. Using an unstructured set of overlapping photographs captured from multiple viewpoints and minimal GPS ground control, SfM solves simultaneously for scene topography and camera positions, orientations and lens parameters. The use of cheap unmanned aerial vehicles or tethered helium balloons as camera platforms expedites data collection and overcomes many of the cost, time and logistical limitations of LiDAR surveying, making it a potentially valuable tool for rapid response mapping and repeat monitoring applications. We begin this presentation by assessing what data resolutions and precisions are achievable using a simple aerial camera platform and commercial SfM software (we use the popular Agisoft Photoscan package). SfM point clouds generated at two small (~0.1 km2), sparsely-vegetated field sites in California compare favorably with overlapping airborne and terrestrial LiDAR surveys, with closest point distances of a few centimeters between the independent datasets. Next, we go on to explore the method in more challenging conditions, in response to a major landslide in Mesa County, Colorado, on 25th May 2014. Photographs collected from a small UAV were used to generate a high-resolution model of the 4.5 x 1 km landslide several days before an airborne LiDAR survey could be organized and flown. An initial estimate of the mass balance of the landslide could quickly be made by differencing this model against pre-event topography generated using stereo photographs collected in 2009 as part of the National Agricultural Imagery Program (NAIP). This case study therefore demonstrates the rich potential offered by this technique, as well as some of the challenges, particularly with respect to the treatment of vegetation.

  14. Rapid mapping of ultrafine fault zone topography with structure from motion

    Science.gov (United States)

    Johnson, Kendra; Nissen, Edwin; Saripalli, Srikanth; Arrowsmith, J. Ramón; McGarey, Patrick; Scharer, Katherine M.; Williams, Patrick; Blisniuk, Kimberly

    2014-01-01

    Structure from Motion (SfM) generates high-resolution topography and coregistered texture (color) from an unstructured set of overlapping photographs taken from varying viewpoints, overcoming many of the cost, time, and logistical limitations of Light Detection and Ranging (LiDAR) and other topographic surveying methods. This paper provides the first investigation of SfM as a tool for mapping fault zone topography in areas of sparse or low-lying vegetation. First, we present a simple, affordable SfM workflow, based on an unmanned helium balloon or motorized glider, an inexpensive camera, and semiautomated software. Second, we illustrate the system at two sites on southern California faults covered by existing airborne or terrestrial LiDAR, enabling a comparative assessment of SfM topography resolution and precision. At the first site, an ∼0.1 km2 alluvial fan on the San Andreas fault, a colored point cloud of density mostly >700 points/m2 and a 3 cm digital elevation model (DEM) and orthophoto were produced from 233 photos collected ∼50 m above ground level. When a few global positioning system ground control points are incorporated, closest point vertical distances to the much sparser (∼4 points/m2) airborne LiDAR point cloud are mostly 530 points/m2 and a 2 cm DEM and orthophoto were produced from 450 photos taken from ∼60 m above ground level. Closest point vertical distances to existing terrestrial LiDAR data of comparable density are mostly geomorphic offsets related to past earthquakes as well as rapid response mapping or long-term monitoring of faulted landscapes.

  15. 3D topography measurements on correlation cells—a new approach to forensic ballistics identifications

    Science.gov (United States)

    Song, John; Chu, Wei; Tong, Mingsi; Soons, Johannes

    2014-06-01

    Based on three-dimensional (3D) topography measurements on correlation cells, the National Institute of Standards and Technology (NIST) has developed the ‘NIST Ballistics Identification System (NBIS)’ aimed at accurate ballistics identifications and fast ballistics evidence searches. The 3D topographies are divided into arrays of correlation cells to identify ‘valid correlation areas’ and eliminate ‘invalid correlation areas’ from the matching and identification procedure. A ‘congruent matching cells’ (CMC)’ method using three types of identification parameters of the paired correlation cells (cross correlation function maximum CCFmax, spatial registration position in x-y and registration angle θ) is used for high accuracy ballistics identifications. ‘Synchronous processing’ is proposed for correlating multiple cell pairs at the same time to increase the correlation speed. The proposed NBIS can be used for correlations of both geometrical topographies and optical intensity images. All the correlation parameters and algorithms are in the public domain and subject to open tests. An error rate reporting procedure has been developed that can greatly add to the scientific support for the firearm and toolmark identification specialty, and give confidence to the trier of fact in court proceedings. The NBIS is engineered to employ transparent identification parameters and criteria, statistical models and correlation algorithms. In this way, interoperability between different ballistics identification systems can be more easily achieved. This interoperability will make the NBIS suitable for ballistics identifications and evidence searches with large national databases, such as the National Integrated Ballistic Information Network in the United States.

  16. Colorimetric and dynamic light scattering detection of DNA sequences by using positively charged gold nanospheres: a comparative study with gold nanorods

    Science.gov (United States)

    Pylaev, T. E.; Khanadeev, V. A.; Khlebtsov, B. N.; Dykman, L. A.; Bogatyrev, V. A.; Khlebtsov, N. G.

    2011-07-01

    We introduce a new genosensing approach employing CTAB (cetyltrimethylammonium bromide)-coated positively charged colloidal gold nanoparticles (GNPs) to detect target DNA sequences by using absorption spectroscopy and dynamic light scattering. The approach is compared with a previously reported method employing unmodified CTAB-coated gold nanorods (GNRs). Both approaches are based on the observation that whereas the addition of probe and target ssDNA to CTAB-coated particles results in particle aggregation, no aggregation is observed after addition of probe and nontarget DNA sequences. Our goal was to compare the feasibility and sensitivity of both methods. A 21-mer ssDNA from the human immunodeficiency virus type 1 HIV-1 U5 long terminal repeat (LTR) sequence and a 23-mer ssDNA from the Bacillus anthracis cryptic protein and protective antigen precursor (pagA) genes were used as ssDNA models. In the case of GNRs, unexpectedly, the colorimetric test failed with perfect cigar-like particles but could be performed with dumbbell and dog-bone rods. By contrast, our approach with cationic CTAB-coated GNPs is easy to implement and possesses excellent feasibility with retention of comparable sensitivity—a 0.1 nM concentration of target cDNA can be detected with the naked eye and 10 pM by dynamic light scattering (DLS) measurements. The specificity of our method is illustrated by successful DLS detection of one-three base mismatches in cDNA sequences for both DNA models. These results suggest that the cationic GNPs and DLS can be used for genosensing under optimal DNA hybridization conditions without any chemical modifications of the particle surface with ssDNA molecules and signal amplification. Finally, we discuss a more than two-three-order difference in the reported estimations of the detection sensitivity of colorimetric methods (0.1 to 10-100 pM) to show that the existing aggregation models are inconsistent with the detection limits of about 0.1-1 pM DNA and that

  17. Power laws for gravity and topography of Solar System bodies

    Science.gov (United States)

    Ermakov, A.; Park, R. S.; Bills, B. G.

    2017-12-01

    When a spacecraft visits a planetary body, it is useful to be able to predict its gravitational and topographic properties. This knowledge is important for determining the level of perturbations in spacecraft's motion as well as for planning the observation campaign. It has been known for the Earth that the power spectrum of gravity follows a power law, also known as the Kaula rule (Kaula, 1963; Rapp, 1989). A similar rule was derived for topography (Vening-Meinesz, 1951). The goal of this paper is to generalize the power law that can characterize the gravity and topography power spectra for bodies across a wide range of size. We have analyzed shape power spectra of the bodies that have either global shape and gravity field measured. These bodies span across five orders of magnitude in their radii and surface gravities and include terrestrial planets, icy moons and minor bodies. We have found that despite having different internal structure, composition and mechanical properties, the topography power spectrum of these bodies' shapes can be modeled with a similar power law rescaled by the surface gravity. Having empirically found a power law for topography, we can map it to a gravity power law. Special care should be taken for low-degree harmonic coefficients due to potential isostatic compensation. For minor bodies, uniform density can be assumed. The gravity coefficients are a linear function of the shape coefficients for close-to-spherical bodoes. In this case, the power law for gravity will be steeper than the power law of topography due to the factor (2n+1) in the gravity expansion (e.g. Eq. 10 in Wieczorek & Phillips, 1998). Higher powers of topography must be retained for irregularly shaped bodies, which breaks the linearity. Therefore, we propose the following procedure to derive an a priori constraint for gravity. First, a surface gravity needs to be determined assuming typical density for the relevant class of bodies. Second, the scaling coefficient of the

  18. Topography changes monitoring of small islands using camera drone

    Science.gov (United States)

    Bang, E.

    2017-12-01

    Drone aerial photogrammetry was conducted for monitoring topography changes of small islands in the east sea of Korea. Severe weather and sea wave is eroding the islands and sometimes cause landslide and falling rock. Due to rugged cliffs in all direction and bad accessibility, ground based survey methods are less efficient in monitoring topography changes of the whole area. Camera drones can provide digital images and movie in every corner of the islands, and drone aerial photogrammetry is powerful to get precise digital surface model (DSM) for a limited area. We have got a set of digital images to construct a textured 3D model of the project area every year since 2014. Flight height is in less than 100m from the top of those islands to get enough ground sampling distance (GSD). Most images were vertically captured with automatic flights, but we also flied drones around the islands with about 30°-45° camera angle for constructing 3D model better. Every digital image has geo-reference, but we set several ground control points (GCPs) on the islands and their coordinates were measured with RTK surveying methods to increase the absolute accuracy of the project. We constructed 3D textured model using photogrammetry tool, which generates 3D spatial information from digital images. From the polygonal model, we could get DSM with contour lines. Thematic maps such as hill shade relief map, aspect map and slope map were also processed. Those maps make us understand topography condition of the project area better. The purpose of this project is monitoring topography change of these small islands. Elevation difference map between DSMs of each year is constructed. There are two regions showing big negative difference value. By comparing constructed textured models and captured digital images around these regions, it is checked that a region have experienced real topography change. It is due to huge rock fall near the center of the east island. The size of fallen rock can be

  19. Positive enhancement integral values in dynamic contrast enhanced magnetic resonance imaging of breast carcinoma: Ductal carcinoma in situ vs. invasive ductal carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Nadrljanski, Mirjan, E-mail: dr.m.nadrljanski@gmail.com [Clinic for Radiology and Radiation Oncology, Institute of Oncology and Radiology of Serbia, Pasterova 14, 11000 Belgrade (Serbia); Maksimović, Ružica [Center for Radiology and Magnetic Resonance Imaging, Clinical Center of Serbia, Pasterova 2, 11000 Belgrade (Serbia); Faculty of Medicine, University of Belgrade, Dr Subotića 8, 11000 Belgrade (Serbia); Plešinac-Karapandžić, Vesna; Nikitović, Marina [Clinic for Radiology and Radiation Oncology, Institute of Oncology and Radiology of Serbia, Pasterova 14, 11000 Belgrade (Serbia); Faculty of Medicine, University of Belgrade, Dr Subotića 8, 11000 Belgrade (Serbia); Marković-Vasiljković, Biljana [Center for Radiology and Magnetic Resonance Imaging, Clinical Center of Serbia, Pasterova 2, 11000 Belgrade (Serbia); Faculty of Medicine, University of Belgrade, Dr Subotića 8, 11000 Belgrade (Serbia); Milošević, Zorica [Clinic for Radiology and Radiation Oncology, Institute of Oncology and Radiology of Serbia, Pasterova 14, 11000 Belgrade (Serbia); Faculty of Medicine, University of Belgrade, Dr Subotića 8, 11000 Belgrade (Serbia)

    2014-08-15

    Objectives: The aim of this study was to contribute to the standardization of the numeric positive enhancement integral (PEI) values in breast parenchyma, ductal carcinoma in situ (DCIS) and invasive ductal carcinoma (IDC) and to evaluate the significance of the difference in PEI values between IDC and parenchyma, DCIS and parenchyma and IDC and DCIS. Materials and Methods: In the prospective trial, we analyzed the dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) of 60 consecutive patients with histologically confirmed unilateral DCIS (n = 30) and IDC (n = 30) and defined the PEI values (range; mean ± SD) for the lesions and the breast parenchyma. Tumor-to-non-tumor (T/NT) ratios were calculated for DCIS and IDC and compared. PEI color maps (PEICM) were created. The differences in PEI values between IDC and parenchyma and between DCIS and parenchyma were tested according to t-test. Analysis of variance (ANOVA) was used to test the differences between the mean PEI values of parenchyma, DCIS and IDC. Results: IDC showed highly statistically different PEI numeric values compared to breast parenchyma (748.7 ± 32.2 vs. 74.6 ± 17.0; p < 0.0001). The same applied to the differences in the group of patients with DCIS (428.0 ± 25.0 vs. 66.0 ± 10.6; p < 0.0001). The difference between IDC, DCIS and parenchyma were also considered highly statistically significant (p < 0.0001) and so were the T/NT ratios for IDC and DCIS (10.1 ± 2.4 vs. 6.6 ± 1.4; p < 0.0001). Conclusions: PEI numeric values may contribute to differentiation between invasive and in situ breast carcinoma.

  20. Method and Apparatus for Creating a Topography at a Surface

    Science.gov (United States)

    Adams, David P.; Sinclair, Michael B.; Mayer, Thomas M.; Vasile, Michael J.; Sweatt, William C.

    2008-11-11

    Methods and apparatus whereby an optical interferometer is utilized to monitor and provide feedback control to an integrated energetic particle column, to create desired topographies, including the depth, shape and/or roughness of features, at a surface of a specimen. Energetic particle columns can direct energetic species including, ions, photons and/or neutral particles to a surface to create features having in-plane dimensions on the order of 1 micron, and a height or depth on the order of 1 nanometer. Energetic processes can include subtractive processes such as sputtering, ablation, focused ion beam milling and, additive processes, such as energetic beam induced chemical vapor deposition. The integration of interferometric methods with processing by energetic species offers the ability to create desired topographies at surfaces, including planar and curved shapes.

  1. Noise evaluation of a point autofocus surface topography measuring instrument

    Science.gov (United States)

    Maculotti, Giacomo; Feng, Xiaobing; Galetto, Maurizio; Leach, Richard

    2018-06-01

    In this work, the measurement noise of a point autofocus surface topography measuring instrument is evaluated, as the first step towards establishing a route to traceability for this type of instrument. The evaluation is based on the determination of the metrological characteristics for noise as outlined in draft ISO specification standards by using a calibrated optical flat. The static noise and repeatability of the autofocus sensor are evaluated. The influence of environmental disturbances on the measured surface topography and the built-in software to compensate for such influences are also investigated. The instrument was found to have a measurement noise of approximately 2 nm or, when expressed with the measurement bandwidth, 0.4 nm for a single-point measurement.

  2. Surface topography of parallel grinding process for nonaxisymmetric aspheric lens

    International Nuclear Information System (INIS)

    Zhang Ningning; Wang Zhenzhong; Pan Ri; Wang Chunjin; Guo Yinbiao

    2012-01-01

    Workpiece surface profile, texture and roughness can be predicted by modeling the topography of wheel surface and modeling kinematics of grinding process, which compose an important part of precision grinding process theory. Parallel grinding technology is an important method for nonaxisymmetric aspheric lens machining, but there is few report on relevant simulation. In this paper, a simulation method based on parallel grinding for precision machining of aspheric lens is proposed. The method combines modeling the random surface of wheel and modeling the single grain track based on arc wheel contact points. Then, a mathematical algorithm for surface topography is proposed and applied in conditions of different machining parameters. The consistence between the results of simulation and test proves that the algorithm is correct and efficient. (authors)

  3. High resolution, monochromatic x-ray topography capability at CHESS

    Energy Technology Data Exchange (ETDEWEB)

    Finkelstein, K. D., E-mail: kdf1@cornell.edu; Pauling, A.; Brown, Z. [CHESS, Cornell University, Ithaca, NY (United States); Jones, R. [Department of Physics, University of Connecticut, Storrs, CT (United States); Tarun, A.; Misra, D. S. [IIa Technologies (Singapore); Jupitz, S. [St. Mary’s College of Maryland, St. Mary’s City, MD (United States); Sagan, D. C. [CLASSE, Cornell University, Ithaca, NY (United States)

    2016-07-27

    CHESS has a monochromatic x-ray topography capability serving continually expanding user interest. The setup consists of a beam expanding monochromator, 6-circle diffactometer, and CHESS designed CMOS camera with real time sample-alignment capability. This provides rocking curve mapping with angle resolution as small as 2 µradians, spatial resolution to 3 microns, and field of view up to 7mm. Thus far the capability has been applied for: improving CVD-diamond growth, evaluating perfection of ultra-thin diamond membranes, correlating performance of diamond-based electronics with crystal defect structure, and defect analysis of single crystal silicon carbide. This paper describes our topography system, explains its capabilities, and presents experimental results from several applications.

  4. High resolution, monochromatic x-ray topography capability at CHESS

    International Nuclear Information System (INIS)

    Finkelstein, K. D.; Pauling, A.; Brown, Z.; Jones, R.; Tarun, A.; Misra, D. S.; Jupitz, S.; Sagan, D. C.

    2016-01-01

    CHESS has a monochromatic x-ray topography capability serving continually expanding user interest. The setup consists of a beam expanding monochromator, 6-circle diffactometer, and CHESS designed CMOS camera with real time sample-alignment capability. This provides rocking curve mapping with angle resolution as small as 2 µradians, spatial resolution to 3 microns, and field of view up to 7mm. Thus far the capability has been applied for: improving CVD-diamond growth, evaluating perfection of ultra-thin diamond membranes, correlating performance of diamond-based electronics with crystal defect structure, and defect analysis of single crystal silicon carbide. This paper describes our topography system, explains its capabilities, and presents experimental results from several applications.

  5. Topography and refractometry of nanostructures using spatial light interference microscopy.

    Science.gov (United States)

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

    2010-01-15

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

  6. Diffusion processes in bombardment-induced surface topography

    International Nuclear Information System (INIS)

    Robinson, R.S.

    1984-01-01

    The bombardment of surfaces with moderate energy ions can lead to the development of various micron-sized surface structures. These structures include ridges, ledges, flat planes, pits and cones. The causal phenomena in the production of these features are sputtering, ion reflection, redeposition of sputtered material, and surface diffusion of both impurity and target-atom species. The authors concentrate on the formation of ion bombardment-induced surface topography wherein surface diffusion is a dominant process. The most thoroughly understood aspect of this topography development is the generation of cone-like structures during sputtering. The formation of cones during sputtering has been attributed to three effects. These are: (1) the presence of asperities, defects, or micro-inclusions in the surface layers, (2) the presence of impurities on the surfaces, and (3) particular crystal orientations. (Auth.)

  7. Signal filtering algorithm for depth-selective diffuse optical topography

    International Nuclear Information System (INIS)

    Fujii, M; Nakayama, K

    2009-01-01

    A compact filtered backprojection algorithm that suppresses the undesirable effects of skin circulation for near-infrared diffuse optical topography is proposed. Our approach centers around a depth-selective filtering algorithm that uses an inverse problem technique and extracts target signals from observation data contaminated by noise from a shallow region. The filtering algorithm is reduced to a compact matrix and is therefore easily incorporated into a real-time system. To demonstrate the validity of this method, we developed a demonstration prototype for depth-selective diffuse optical topography and performed both computer simulations and phantom experiments. The results show that the proposed method significantly suppresses the noise from the shallow region with a minimal degradation of the target signal.

  8. A three-dimensional viscous topography mesoscale model

    Energy Technology Data Exchange (ETDEWEB)

    Eichhorn, J; Flender, M; Kandlbinder, T; Panhans, W G; Trautmann, T; Zdunkowski, W G [Mainz Univ. (Germany). Inst. fuer Physik der Atmosphaere; Cui, K; Ries, R; Siebert, J; Wedi, N

    1997-11-01

    This study describes the theoretical foundation and applications of a newly designed mesoscale model named CLIMM (climate model Mainz). In contrast to terrain following coordinates, a cartesian grid is used to keep the finite difference equations as simple as possible. The method of viscous topography is applied to the flow part of the model. Since the topography intersects the cartesian grid cells, the new concept of boundary weight factors is introduced for the solution of Poisson`s equation. A three-dimensional radiosity model was implemented to handle radiative transfer at the ground. The model is applied to study thermally induced circulations and gravity waves at an idealized mountain. Furthermore, CLIMM was used to simulate typical wind and temperature distributions for the city of Mainz and its rural surroundings. It was found that the model in all cases produced realistic results. (orig.) 38 refs.

  9. Geomorphic Transport Laws and the Statistics of Topography and Stratigraphy

    Science.gov (United States)

    Schumer, R.; Taloni, A.; Furbish, D. J.

    2016-12-01

    Geomorphic transport laws take the form of partial differential equations in which sediment motion is a deterministic function of slope. The addition of a noise term, representing unmeasurable, or subgrid scale autogenic forcing, reproduces scaling properties similar to those observed in topography, landforms, and stratigraphy. Here we describe a transport law that generalizes previous equations by permitting transport that is local or non-local in addition to different types of noise. More importantly, we use this transport law to link the character of sediment transport to the statistics of topography and stratigraphy. In particular, we link the origin of the Sadler effect to the evolution of the earth surface via a transport law.

  10. The Relationship between Trail Running Withdrawals and Race Topography

    Directory of Open Access Journals (Sweden)

    Antonini Philippe Roberta

    2017-12-01

    Full Text Available Context: A growing amount of recent research in sport psychology has focused on trying to understand withdrawals from ultra-races. However, according to the Four E approach, the studies underestimated the embedded components of these experiences and particularly how they were linked to the specific environmental conditions in which the experiences occurred. Objective: This study aimed to characterize trail running withdrawals in relationship to race topography. Design: Qualitative design, involving self-confrontation interviews and use of a race map. Setting: Use of the race map for description of the race activity and self-confrontation interviews took place 1–3 days after the races. Participants: Ten runners who withdrew during an ultra-trail race. Data Collection and Analysis: Data on past activity traces and experiences were elicited from self-confrontation interviews. Data were coded and compared to identify common sequences and then each type of sequence was counted with regard to race topography. Results: Results showed that each sequence was related to runners’ particular possibilities for acting, feeling, and thinking, which were in turn embedded in the race topography. These sequences allowed the unfolding of the activity and increased its overall effectiveness in relation to the constraints of this specific sport. Conclusion: This study allowed us to highlight important information on how ultra-trail runners manage their races in relationship to the race environment and more specifically to its topography. The result will also help us to recommend potential adjustments to ultra-trail runners’ performance-oriented training and preparation.

  11. Outcomes of photorefractive keratectomy in patients with atypical topography.

    Science.gov (United States)

    Movahedan, Hossein; Namvar, Ehsan; Farvardin, Mohsen

    2017-11-01

    Photorefractive keratectomy (PRK) is at risk of serious complications such as corneal ectasia, which can reduce corrected distance visual acuity. The rate of complications of PRK is higher in patients with atypical topography. To determine the outcomes of photorefractive keratectomy in patients with atypical topography. This cross-sectional study was done in 2015 in Shiraz in Iran. We included 85 eyes in this study. The samples were selected using a simple random sampling method. All patients were under evaluation for uncorrected distance visual acuity, corrected distance visual acuity, manifest refraction, corneal topography, central corneal thickness using pentacam, slit-lamp microscopy, and detailed fondus evaluation. The postoperative examination was done 1-7 years after surgery. Data were analyzed using IBM SPSS 21.0 version. To analyze the data, descriptive statistics (frequency, percentage, mean, and standard deviation), chi-square, and independent samples t-test were used. We studied 85 eyes. Among the patients, 23 (27.1%) were male and 62 (72.9%) were female. Mean age of the participants was 28.25±5.55 years. Mean postoperative refraction was - 0.37±0.55 diopters. Keratoconus or corneal ectasia was not reported in any patient in this study. There was no statistically significant difference between SI index before and after operation (p=0.736). Mean preoperative refraction was -3.84 ± 1.46 diopters in males and -4.20±1.96 diopters in females; thus there was not statistically significant difference (p = 0.435). PRK is a safe and efficient photorefractive surgery and is associated with low complication rate in patients with atypical topography.

  12. Electronic cigarettes: abuse liability, topography and subjective effects.

    Science.gov (United States)

    Evans, Sarah E; Hoffman, Allison C

    2014-05-01

    To review the available evidence evaluating the abuse liability, topography, subjective effects, craving and withdrawal suppression associated with e-cigarette use in order to identify information gaps and provide recommendations for future research. Literature searches were conducted between October 2012 and January 2014 using five electronic databases. Studies were included in this review if they were peer-reviewed scientific journal articles evaluating clinical laboratory studies, national surveys or content analyses. A total of 15 peer-reviewed articles regarding behavioural use and effects of e-cigarettes published between 2010 and 2014 were included in this review. Abuse liability studies are limited in their generalisability. Topography (consumption behaviour) studies found that, compared with traditional cigarettes, e-cigarette average puff duration was significantly longer, and e-cigarette use required stronger suction. Data on e-cigarette subjective effects (such as anxiety, restlessness, concentration, alertness and satisfaction) and withdrawal suppression are limited and inconsistent. In general, study data should be interpreted with caution, given limitations associated with comparisons of novel and usual products, as well as the possible effects associated with subjects' previous experience/inexperience with e-cigarettes. Currently, very limited information is available on abuse liability, topography and subjective effects of e-cigarettes. Opportunities to examine extended e-cigarette use in a variety of settings with experienced e-cigarette users would help to more fully assess topography as well as behavioural and subjective outcomes. In addition, assessment of 'real-world' use, including amount and timing of use and responses to use, would clarify behavioural profiles and potential adverse health effects.

  13. Morphology and Topography of Retinal Pericytes in the Living Mouse Retina Using In Vivo Adaptive Optics Imaging and Ex Vivo Characterization

    Science.gov (United States)

    Schallek, Jesse; Geng, Ying; Nguyen, HoanVu; Williams, David R.

    2013-01-01

    Purpose. To noninvasively image retinal pericytes in the living eye and characterize NG2-positive cell topography and morphology in the adult mouse retina. Methods. Transgenic mice expressing fluorescent pericytes (NG2, DsRed) were imaged using a two-channel, adaptive optics scanning laser ophthalmoscope (AOSLO). One channel imaged vascular perfusion with near infrared light. A second channel simultaneously imaged fluorescent retinal pericytes. Mice were also imaged using wide-field ophthalmoscopy. To confirm in vivo imaging, five eyes were enucleated and imaged in flat mount with conventional fluorescent microscopy. Cell topography was quantified relative to the optic disc. Results. We observed strong DsRed fluorescence from NG2-positive cells. AOSLO revealed fluorescent vascular mural cells enveloping all vessels in the living retina. Cells were stellate on larger venules, and showed banded morphology on arterioles. NG2-positive cells indicative of pericytes were found on the smallest capillaries of the retinal circulation. Wide-field SLO enabled quick assessment of NG2-positive distribution, but provided insufficient resolution for cell counts. Ex vivo microscopy showed relatively even topography of NG2-positive capillary pericytes at eccentricities more than 0.3 mm from the optic disc (515 ± 94 cells/mm2 of retinal area). Conclusions. We provide the first high-resolution images of retinal pericytes in the living animal. Subcellular resolution enabled morphological identification of NG2-positive cells on capillaries showing classic features and topography of retinal pericytes. This report provides foundational basis for future studies that will track and quantify pericyte topography, morphology, and function in the living retina over time, especially in the progression of microvascular disease. PMID:24150762

  14. Examinations for quantifying the difference in radiation doses at the least favorable locations between facility sites in highly structured topographies (valleys) and in plane terrain (licensing procedures); Untersuchungen zur Quantifizierung des Unterschieds in der Dosisbelastung am unguenstigsten Aufpunkt zwischen Standorten in topographisch stark strukturiertem Gelaende (Tal-Lagen) und in ebenem Terrain (Genehmigungsverfahren)

    Energy Technology Data Exchange (ETDEWEB)

    Raskob, W. [Dr. Trippe Ingenieurgesellschaft mbH, Karlsruhe (Germany)

    1995-08-01

    The MCF wind field model and the LASAT Lagrange particle model served to study topography effects on the spreading of radionuclides. Concentrations in bottom layers of the atmosphere at maximum-dose positions in hilly country topography are up to a factor 6 higher than in plain country. For concentrations in the soil the results have a similar relation. (orig.)

  15. Cellular Scale Anisotropic Topography Guides Schwann Cell Motility

    Science.gov (United States)

    Mitchel, Jennifer A.; Hoffman-Kim, Diane

    2011-01-01

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

  16. Applications of corneal topography and tomography: a review.

    Science.gov (United States)

    Fan, Rachel; Chan, Tommy Cy; Prakash, Gaurav; Jhanji, Vishal

    2018-03-01

    Corneal imaging is essential for diagnosing and management of a wide variety of ocular diseases. Corneal topography is used to characterize the shape of the cornea, specifically, the anterior surface of the cornea. Most corneal topographical systems are based on Placido disc that analyse rings that are reflected off the corneal surface. The posterior corneal surface cannot be characterized using Placido disc technology. Imaging of the posterior corneal surface is useful for diagnosis of corneal ectasia. Unlike corneal topographers, tomographers generate a three-dimensional recreation of the anterior segment and provide information about the corneal thickness. Scheimpflug imaging is one of the most commonly used techniques for corneal tomography. The cross-sectional images generated by a rotating Scheimpflug camera are used to locate the anterior and posterior corneal surfaces. The clinical uses of corneal topography include, diagnosis of corneal ectasia, assessment of corneal astigmatism, and refractive surgery planning. This review will discuss the applications of corneal topography and tomography in clinical practice. © 2017 Royal Australian and New Zealand College of Ophthalmologists.

  17. Topography significantly influencing low flows in snow-dominated watersheds

    Science.gov (United States)

    Li, Qiang; Wei, Xiaohua; Yang, Xin; Giles-Hansen, Krysta; Zhang, Mingfang; Liu, Wenfei

    2018-03-01

    Watershed topography plays an important role in determining the spatial heterogeneity of ecological, geomorphological, and hydrological processes. Few studies have quantified the role of topography in various flow variables. In this study, 28 watersheds with snow-dominated hydrological regimes were selected with daily flow records from 1989 to 1996. These watersheds are located in the Southern Interior of British Columbia, Canada, and range in size from 2.6 to 1780 km2. For each watershed, 22 topographic indices (TIs) were derived, including those commonly used in hydrology and other environmental fields. Flow variables include annual mean flow (Qmean), Q10 %, Q25 %, Q50 %, Q75 %, Q90 %, and annual minimum flow (Qmin), where Qx % is defined as the daily flow that occurred each year at a given percentage (x). Factor analysis (FA) was first adopted to exclude some redundant or repetitive TIs. Then, multiple linear regression models were employed to quantify the relative contributions of TIs to each flow variable in each year. Our results show that topography plays a more important role in low flows (flow magnitudes ≤ Q75 %) than high flows. However, the effects of TIs on different flow magnitudes are not consistent. Our analysis also determined five significant TIs: perimeter, slope length factor, surface area, openness, and terrain characterization index. These can be used to compare watersheds when low flow assessments are conducted, specifically in snow-dominated regions with the watershed size less than several thousand square kilometres.

  18. Age and Prematurity of the Alps Derived from Topography

    Science.gov (United States)

    Hergarten, S.; Wagner, T.; Stüwe, K.

    2010-09-01

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

  19. Topography and instability of monolayers near domain boundaries

    International Nuclear Information System (INIS)

    Diamant, H.; Witten, T. A.; Ege, C.; Gopal, A.; Lee, K. Y. C.

    2001-01-01

    We theoretically study the topography of a biphasic surfactant monolayer in the vicinity of domain boundaries. The differing elastic properties of the two phases generally lead to a nonflat topography of 'mesas,' where domains of one phase are elevated with respect to the other phase. The mesas are steep but low, having heights of up to 10 nm. As the monolayer is laterally compressed, the mesas develop overhangs and eventually become unstable at a surface tension of about K(δc 0 ) 2 (δc 0 being the difference in spontaneous curvature and K a bending modulus). In addition, the boundary is found to undergo a topography-induced rippling instability upon compression, if its line tension is smaller than about Kδc 0 . The effect of diffuse boundaries on these features and the topographic behavior near a critical point are also examined. We discuss the relevance of our findings to several experimental observations related to surfactant monolayers: (i) small topographic features recently found near domain boundaries; (ii) folding behavior observed in mixed phospholipid monolayers and model lung surfactants; (iii) roughening of domain boundaries seen under lateral compression; (iv) the absence of biphasic structures in tensionless surfactant films

  20. Roles of Fog and Topography in Redwood Forest Hydrology

    Science.gov (United States)

    Francis, E. J.; Asner, G. P.

    2017-12-01

    Spatial variability of water in forests is a function of both climatic gradients that control water inputs and topo-edaphic variation that determines the flows of water belowground, as well as interactions of climate with topography. Coastal redwood forests are hydrologically unique because they are influenced by coastal low clouds, or fog, that is advected onto land by a strong coastal-to-inland temperature difference. Where fog intersects the land surface, annual water inputs from summer fog drip can be greater than that of winter rainfall. In this study, we take advantage of mapped spatial gradients in forest canopy water storage, topography, and fog cover in California to better understand the roles and interactions of fog and topography in the hydrology of redwood forests. We test a conceptual model of redwood forest hydrology with measurements of canopy water content derived from high-resolution airborne imaging spectroscopy, topographic variables derived from high-resolution LiDAR data, and fog cover maps derived from NASA MODIS data. Landscape-level results provide insight into hydrological processes within redwood forests, and cross-site analyses shed light on their generality.

  1. Smoking topography in Korean American and white men: preliminary findings.

    Science.gov (United States)

    Chung, Sangkeun; Kim, Sun S; Kini, Nisha; Fang, Hua J; Kalman, David; Ziedonis, Douglas M

    2015-06-01

    This is the first study of Korean Americans' smoking behavior using a topography device. Korean American men smoke at higher rates than the general U.S. Korean American and White men were compared based on standard tobacco assessment and smoking topography measures. They smoked their preferred brand of cigarettes ad libitum with a portable smoking topography device for 24 h. Compared to White men (N = 26), Korean American men (N = 27) were more likely to smoke low nicotine-yield cigarettes (p Whites. Controlling for the number of cigarettes smoked, Koreans smoked with higher average puff flows (p = 0.05), greater peak puff flows (p = 0.02), and shorter interpuff intervals (p Whites. Puff counts, puff volumes, and puff durations did not differ between the two groups. This study offers preliminary insight into unique smoking patterns among Korean American men who are likely to smoke low nicotine-yield cigarettes. We found that Korean American men compensated their lower number and low nicotine-yield cigarettes by smoking with greater puff flows and shorter interpuff intervals than White men, which may suggest exposures to similar amounts of nicotine and harmful tobacco toxins by both groups. Clinicians will need to consider in identifying and treating smokers in a mutually aggressive manner, irrespective of cigarette type and number of cigarette smoked per day.

  2. Diffusive boundary layers over varying topography

    KAUST Repository

    Dell, R. W.

    2015-03-25

    Diffusive bottom boundary layers can produce upslope flows in a stratified fluid. Accumulating observations suggest that these boundary layers may drive upwelling and mixing in mid-ocean ridge flank canyons. However, most studies of diffusive bottom boundary layers to date have concentrated on constant bottom slopes. We present a study of how diffusive boundary layers interact with various idealized topography, such as changes in bottom slope, slopes with corrugations and isolated sills. We use linear theory and numerical simulations in the regional ocean modeling system (ROMS) model to show changes in bottom slope can cause convergences and divergences within the boundary layer, in turn causing fluid exchanges that reach far into the overlying fluid and alter stratification far from the bottom. We also identify several different regimes of boundary-layer behaviour for topography with oceanographically relevant size and shape, including reversing flows and overflows, and we develop a simple theory that predicts the regime boundaries, including what topographies will generate overflows. As observations also suggest there may be overflows in deep canyons where the flow passes over isolated bumps and sills, this parameter range may be particularly significant for understanding the role of boundary layers in the deep ocean.

  3. Nano-topography Enhances Communication in Neural Cells Networks

    KAUST Repository

    Onesto, V.

    2017-08-23

    Neural cells are the smallest building blocks of the central and peripheral nervous systems. Information in neural networks and cell-substrate interactions have been heretofore studied separately. Understanding whether surface nano-topography can direct nerve cells assembly into computational efficient networks may provide new tools and criteria for tissue engineering and regenerative medicine. In this work, we used information theory approaches and functional multi calcium imaging (fMCI) techniques to examine how information flows in neural networks cultured on surfaces with controlled topography. We found that substrate roughness Sa affects networks topology. In the low nano-meter range, S-a = 0-30 nm, information increases with Sa. Moreover, we found that energy density of a network of cells correlates to the topology of that network. This reinforces the view that information, energy and surface nano-topography are tightly inter-connected and should not be neglected when studying cell-cell interaction in neural tissue repair and regeneration.

  4. Topography of the Northern Hemisphere of Mercury from MESSENGER Laser Altimetry

    Science.gov (United States)

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

    2012-01-01

    Laser altimetry by the MESSENGER spacecraft has yielded a topographic model of the northern hemisphere of Mercury. The dynamic range of elevations is considerably smaller than those of Mars or the Moon. The most prominent feature is an extensive lowland at high northern latitudes that hosts the volcanic northern plains. Within this lowland is a broad topographic rise that experienced uplift after plains emplacement. The interior of the 1500-km-diameter Caloris impact basin has been modified so that part of the basin floor now stands higher than the rim. The elevated portion of the floor of Caloris appears to be part of a quasi-linear rise that extends for approximately half the planetary circumference at mid-latitudes. Collectively, these features imply that long-wavelength changes to Mercury s topography occurred after the earliest phases of the planet s geological history.

  5. Sequential x-ray diffraction topography at 1-BM x-ray optics testing beamline at the advanced photon source

    Energy Technology Data Exchange (ETDEWEB)

    Stoupin, Stanislav, E-mail: sstoupin@aps.anl.gov; Shvyd’ko, Yuri; Trakhtenberg, Emil; Liu, Zunping; Lang, Keenan; Huang, Xianrong; Wieczorek, Michael; Kasman, Elina; Hammonds, John; Macrander, Albert; Assoufid, Lahsen [Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439 (United States)

    2016-07-27

    We report progress on implementation and commissioning of sequential X-ray diffraction topography at 1-BM Optics Testing Beamline of the Advanced Photon Source to accommodate growing needs of strain characterization in diffractive crystal optics and other semiconductor single crystals. The setup enables evaluation of strain in single crystals in the nearly-nondispersive double-crystal geometry. Si asymmetric collimator crystals of different crystallographic orientations were designed, fabricated and characterized using in-house capabilities. Imaging the exit beam using digital area detectors permits rapid sequential acquisition of X-ray topographs at different angular positions on the rocking curve of a crystal under investigation. Results on sensitivity and spatial resolution are reported based on experiments with high-quality Si and diamond crystals. The new setup complements laboratory-based X-ray topography capabilities of the Optics group at the Advanced Photon Source.

  6. Surface topography of 1€ coin measured by stereo-PIXE

    International Nuclear Information System (INIS)

    Gholami-Hatam, E.; Lamehi-Rachti, M.; Vavpetič, P.; Grlj, N.; Pelicon, P.

    2013-01-01

    We demonstrate the stereo-PIXE method by measurement of surface topography of the relief details on 1€ coin. Two X-ray elemental maps were simultaneously recorded by two X-ray detectors positioned at the left and the right side of the proton microbeam. The asymmetry of the yields in the pixels of the two X-ray maps occurs due to different photon attenuation on the exit travel path of the characteristic X-rays from the point of emission through the sample into the X-ray detectors. In order to calibrate the inclination angle with respect to the X-ray asymmetry, a flat inclined surface model was at first applied for the sample in which the matrix composition and the depth elemental concentration profile is known. After that, the yield asymmetry in each image pixel was transferred into corresponding local inclination angle using calculated dependence of the asymmetry on the surface inclination. Finally, the quantitative topography profile was revealed by integrating the local inclination angle over the lateral displacement of the probing beam

  7. Effects of Management Practices and Topography on Ectomycorrhizal Fungi of Maritime Pine during Seedling Recruitment

    Directory of Open Access Journals (Sweden)

    Arthur Guignabert

    2018-05-01

    Full Text Available Symbiosis with ectomycorrhizal (ECM fungi can be important for regeneration success. In a context of increasing regeneration failures in the coastal forest of maritime pine in Southwest France, we tried to identity whether differences in ECM communities could partly explain the variation of regeneration success and how they are influenced by forest practices and stand characteristics. In particular, we focused on the effects of harvesting methods (comparing mature forest with seed-tree regeneration and clear-cuts and topography (bottom-, mid-, and top positions. Five field trials (two in regeneration failure areas and three in successful areas were used to sample 450 one-year-old seedlings. Assessments of ECM of seedling nutrient concentrations and of seedling growth based on exploration types were made. ECM root colonisation was similar in all harvesting treatments, suggesting that enough inoculum remained alive after logging. Harvesting-induced effects modifying soil properties and light availability respectively impacted ECM composition and seedling growth. Topography-induced variations in water and nutrient availability led to changes in ECM composition, but had little impact on seedling growth. Contact, short-distance, and long-distance exploration types improved the nutritional status of seedlings (Ca, K, and N, showing that mycorrhization could play an important role in seedling vitality. However, neither ECM root colonisation nor exploration types could be related to regeneration failures.

  8. Quantifying the topography of the intrinsic energy landscape of flexible biomolecular recognition

    Science.gov (United States)

    Chu, Xiakun; Gan, Linfeng; Wang, Erkang; Wang, Jin

    2013-01-01

    Biomolecular functions are determined by their interactions with other molecules. Biomolecular recognition is often flexible and associated with large conformational changes involving both binding and folding. However, the global and physical understanding for the process is still challenging. Here, we quantified the intrinsic energy landscapes of flexible biomolecular recognition in terms of binding–folding dynamics for 15 homodimers by exploring the underlying density of states, using a structure-based model both with and without considering energetic roughness. By quantifying three individual effective intrinsic energy landscapes (one for interfacial binding, two for monomeric folding), the association mechanisms for flexible recognition of 15 homodimers can be classified into two-state cooperative “coupled binding–folding” and three-state noncooperative “folding prior to binding” scenarios. We found that the association mechanism of flexible biomolecular recognition relies on the interplay between the underlying effective intrinsic binding and folding energy landscapes. By quantifying the whole global intrinsic binding–folding energy landscapes, we found strong correlations between the landscape topography measure Λ (dimensionless ratio of energy gap versus roughness modulated by the configurational entropy) and the ratio of the thermodynamic stable temperature versus trapping temperature, as well as between Λ and binding kinetics. Therefore, the global energy landscape topography determines the binding–folding thermodynamics and kinetics, crucial for the feasibility and efficiency of realizing biomolecular function. We also found “U-shape” temperature-dependent kinetic behavior and a dynamical cross-over temperature for dividing exponential and nonexponential kinetics for two-state homodimers. Our study provides a unique way to bridge the gap between theory and experiments. PMID:23754431

  9. Metrological characterization methods for confocal chromatic line sensors and optical topography sensors

    Science.gov (United States)

    Seppä, Jeremias; Niemelä, Karri; Lassila, Antti

    2018-05-01

    The increasing use of chromatic confocal technology for, e.g. fast, in-line optical topography, and measuring thickness, roughness and profiles implies a need for the characterization of various aspects of the sensors. Single-point, line and matrix versions of chromatic confocal technology, encoding depth information into wavelength, have been developed. Of these, line sensors are particularly suitable for in-line process measurement. Metrological characterization and development of practical methods for calibration and checking is needed for new optical methods and devices. Compared to, e.g. tactile methods, optical topography measurement techniques have limitations related to light wavelength and coherence, optical properties of the sample including reflectivity, specularity, roughness and colour, and definition of optical versus mechanical surfaces. In this work, metrological characterization methods for optical line sensors were developed for scale magnification and linearity, sensitivity to sample properties, and dynamic characteristics. An accurate depth scale calibration method using a single prototype groove depth sample was developed for a line sensor and validated with laser-interferometric sample tracking, attaining (sub)micrometre level or better than 0.1% scale accuracy. Furthermore, the effect of different surfaces and materials on the measurement and depth scale was studied, in particular slope angle, specularity and colour. In addition, dynamic performance, noise, lateral scale and resolution were measured using the developed methods. In the case of the LCI1200 sensor used in this study, which has a 11.3 mm  ×  2.8 mm measurement range, the instrument depth scale was found to depend only minimally on sample colour, whereas measuring steeply sloped specular surfaces in the peripheral measurement area, in the worst case, caused a somewhat larger relative sample-dependent change (1%) in scale.

  10. Time-varying surface electromyography topography as a prognostic tool for chronic low back pain rehabilitation.

    Science.gov (United States)

    Hu, Yong; Kwok, Jerry Weilun; Tse, Jessica Yuk-Hang; Luk, Keith Dip-Kei

    2014-06-01

    Nonsurgical rehabilitation therapy is a commonly used strategy to treat chronic low back pain (LBP). The selection of the most appropriate therapeutic options is still a big challenge in clinical practices. Surface electromyography (sEMG) topography has been proposed to be an objective assessment of LBP rehabilitation. The quantitative analysis of dynamic sEMG would provide an objective tool of prognosis for LBP rehabilitation. To evaluate the prognostic value of quantitative sEMG topographic analysis and to verify the accuracy of the performance of proposed time-varying topographic parameters for identifying the patients who have better response toward the rehabilitation program. A retrospective study of consecutive patients. Thirty-eight patients with chronic nonspecific LBP and 43 healthy subjects. The accuracy of the time-varying quantitative sEMG topographic analysis for monitoring LBP rehabilitation progress was determined by calculating the corresponding receiver-operating characteristic (ROC) curves. Physiologic measure was the sEMG during lumbar flexion and extension. Patients who suffered from chronic nonspecific LBP without the history of back surgery and any medical conditions causing acute exacerbation of LBP during the clinical test were enlisted to perform the clinical test during the 12-week physiotherapy (PT) treatment. Low back pain patients were classified into two groups: "responding" and "nonresponding" based on the clinical assessment. The responding group referred to the LBP patients who began to recover after the PT treatment, whereas the nonresponding group referred to some LBP patients who did not recover or got worse after the treatment. The results of the time-varying analysis in the responding group were compared with those in the nonresponding group. In addition, the accuracy of the analysis was analyzed through ROC curves. The time-varying analysis showed discrepancies in the root-mean-square difference (RMSD) parameters between the

  11. Expressions for tidal conversion at seafloor topography using physical space integrals

    International Nuclear Information System (INIS)

    Schorghofer, Norbert

    2010-01-01

    The barotropic tide interacts with seafloor topography to generate internal gravity waves. Equations for streamfunction and power conversion are derived in terms of integrals over the topography in spatial coordinates. The slope of the topography does not need to be small. Explicit equations are derived up to second order in slope for general topography, and conversion by a bell-shaped topography is calculated analytically to this order. A concise formalism using Hilbert transforms is developed, the minimally converting topographic shape is discussed, and a numerical scheme for the evaluation of power conversion is designed that robustly deals with the singular integrand.

  12. Puffing Topography and Nicotine Intake of Electronic Cigarette Users

    Science.gov (United States)

    Behar, Rachel Z.; Hua, My; Talbot, Prue

    2015-01-01

    Background Prior electronic cigarette (EC) topography data are based on two video analyses with limited parameters. Alternate methods for measuring topography are needed to understand EC use and nicotine intake. Objectives This study evaluated EC topography with a CReSS Pocket device and quantified nicotine intake. Methods Validation tests on pressure drop, flow rate, and volume confirmed reliable performance of the CReSS Pocket device. Twenty participants used Blu Cigs and V2 Cigs for 10 minute intervals with a 10–15 minute break between brands. Brand order was reversed and repeated within 7 days Data were analyzed to determine puff duration, puff count, volume, flow rate, peak flow, and inter-puff interval. Nicotine intake was estimated from cartomizer fluid consumption and topography data. Results Nine patterns of EC use were identified. The average puff count and inter-puff interval were 32 puffs and 17.9 seconds. All participants, except one, took more than 20 puffs/10 minutes. The averages for puff duration (2.65 seconds/puff), volume/puff (51ml/puff), total puff volume (1,579 ml), EC fluid consumption (79.6 mg), flow rate (20 ml/s), and peak flow rate (27 ml/s) were determined for 10-minute sessions. All parameters except total puff count were significantly different for Blu versus V2 EC. Total volume for Blu versus V2 was four-times higher than for conventional cigarettes. Average nicotine intake for Blu and V2 across both sessions was 1.2 ± 0.5 mg and 1.4 ± 0.7 mg, respectively, which is similar to conventional smokers. Conclusions EC puffing topography was variable among participants in the study, but often similar within an individual between brands or days. Puff duration, inter-puff interval, and puff volume varied from conventional cigarette standards. Data on total puff volume and nicotine intake are consistent with compensatory usage of EC. These data can contribute to the development of a standard protocol for laboratory testing of EC products

  13. Puffing topography and nicotine intake of electronic cigarette users.

    Directory of Open Access Journals (Sweden)

    Rachel Z Behar

    Full Text Available Prior electronic cigarette (EC topography data are based on two video analyses with limited parameters. Alternate methods for measuring topography are needed to understand EC use and nicotine intake.This study evaluated EC topography with a CReSS Pocket device and quantified nicotine intake.Validation tests on pressure drop, flow rate, and volume confirmed reliable performance of the CReSS Pocket device. Twenty participants used Blu Cigs and V2 Cigs for 10 minute intervals with a 10-15 minute break between brands. Brand order was reversed and repeated within 7 days Data were analyzed to determine puff duration, puff count, volume, flow rate, peak flow, and inter-puff interval. Nicotine intake was estimated from cartomizer fluid consumption and topography data.Nine patterns of EC use were identified. The average puff count and inter-puff interval were 32 puffs and 17.9 seconds. All participants, except one, took more than 20 puffs/10 minutes. The averages for puff duration (2.65 seconds/puff, volume/puff (51 ml/puff, total puff volume (1,579 ml, EC fluid consumption (79.6 mg, flow rate (20 ml/s, and peak flow rate (27 ml/s were determined for 10-minute sessions. All parameters except total puff count were significantly different for Blu versus V2 EC. Total volume for Blu versus V2 was four-times higher than for conventional cigarettes. Average nicotine intake for Blu and V2 across both sessions was 1.2 ± 0.5 mg and 1.4 ± 0.7 mg, respectively, which is similar to conventional smokers.EC puffing topography was variable among participants in the study, but often similar within an individual between brands or days. Puff duration, inter-puff interval, and puff volume varied from conventional cigarette standards. Data on total puff volume and nicotine intake are consistent with compensatory usage of EC. These data can contribute to the development of a standard protocol for laboratory testing of EC products.

  14. In Situ Scanning Tunneling Microscopy Topography Changes of Gold (111) in Aqueous Sulfuric Acid Produced by Electrochemical Surface Oxidation and Reduction and Relaxation Phenomena

    Science.gov (United States)

    Pasquale, M. A.; Nieto, F. J. Rodríguez; Arvia, A. J.

    The electrochemical formation and reduction of O-layers on gold (111) films in 1 m sulfuric acid under different potentiodynamic routines are investigated utilizing in situ scanning tunneling microscopy. The surface dynamics is interpreted considering the anodic and cathodic reaction pathways recently proposed complemented with concurrent relaxation phenomena occurring after gold (111) lattice mild disruption (one gold atom deep) and moderate disruption (several atoms deep). The dynamics of both oxidized and reduced gold topographies depends on the potentiodynamic routine utilized to form OH/O surface species. The topography resulting from a mild oxidative disruption is dominated by quasi-2D holes and hillocks of the order of 5 nm, involving about 500-600 gold atoms each, and their coalescence. A cooperative turnover process at the O-layer, in which the anion ad-layer and interfacial water play a key role, determines the oxidized surface topography. The reduction of these O-layers results in gold clusters, their features depending on the applied potential routine. A moderate oxidative disruption produces a surface topography of hillocks and holes several gold atoms high and deep, respectively. The subsequent reduction leads to a spinodal gold pattern. Concurrent coalescence appears to be the result of an Ostwald ripening that involves the surface diffusion of both gold atoms and clusters. These processes produce an increase in surface roughness and an incipient gold faceting. The dynamics of different topographies can be qualitatively explained employing the arguments from colloidal science theory. For 1.1 V ≤ E ≅ Epzc weak electrostatic repulsions favor gold atom/cluster coalescence, whereas for E < Epzc the attenuated electrostatic repulsions among gold surfaces stabilize small clusters over the substrate producing string-like patterns.

  15. Terrain Classification on Venus from Maximum-Likelihood Inversion of Parameterized Models of Topography, Gravity, and their Relation

    Science.gov (United States)

    Eggers, G. L.; Lewis, K. W.; Simons, F. J.; Olhede, S.

    2013-12-01

    Venus does not possess a plate-tectonic system like that observed on Earth, and many surface features--such as tesserae and coronae--lack terrestrial equivalents. To understand Venus' tectonics is to understand its lithosphere, requiring a study of topography and gravity, and how they relate. Past studies of topography dealt with mapping and classification of visually observed features, and studies of gravity dealt with inverting the relation between topography and gravity anomalies to recover surface density and elastic thickness in either the space (correlation) or the spectral (admittance, coherence) domain. In the former case, geological features could be delineated but not classified quantitatively. In the latter case, rectangular or circular data windows were used, lacking geological definition. While the estimates of lithospheric strength on this basis were quantitative, they lacked robust error estimates. Here, we remapped the surface into 77 regions visually and qualitatively defined from a combination of Magellan topography, gravity, and radar images. We parameterize the spectral covariance of the observed topography, treating it as a Gaussian process assumed to be stationary over the mapped regions, using a three-parameter isotropic Matern model, and perform maximum-likelihood based inversions for the parameters. We discuss the parameter distribution across the Venusian surface and across terrain types such as coronoae, dorsae, tesserae, and their relation with mean elevation and latitudinal position. We find that the three-parameter model, while mathematically established and applicable to Venus topography, is overparameterized, and thus reduce the results to a two-parameter description of the peak spectral variance and the range-to-half-peak variance (in function of the wavenumber). With the reduction the clustering of geological region types in two-parameter space becomes promising. Finally, we perform inversions for the JOINT spectral variance of

  16. Crater topography on Titan: Implications for landscape evolution

    Science.gov (United States)

    Neish, C.; Kirk, R.; Lorenz, R.; Bray, V.; Schenk, P.; Stiles, B.; Turtle, E.; Cassini Radar Team

    2012-04-01

    Unique among the icy satellites, Titan’s surface shows evidence for extensive modification by fluvial and aeolian erosion, which act to change the topography of its surface over time. Quantifying the extent of this landscape evolution is difficult, since the original, ‘non-eroded’ surface topography is generally unknown. However, fresh craters on icy satellites have a well-known shape and morphology, which has been determined from extensive studies on the airless worlds of the outer solar system (Schenk et al., 2004). By comparing the topography of craters on Titan to similarly sized, pristine analogues on airless bodies, we can obtain one of the few direct measures of the amount of erosion that has occurred on Titan. Cassini RADAR has imaged >30% of the surface of Titan, and more than 60 potential craters have been identified in this data set (Wood et al., 2010; Neish and Lorenz, 2012). Topographic information for these craters can be obtained from a technique known as ‘SARTopo’, which estimates surface heights by comparing the calibration of overlapping synthetic aperture radar (SAR) beams (Stiles et al., 2009). We present topography data for several craters on Titan, and compare the data to similarly sized craters on Ganymede, for which topography has been extracted from stereo-derived digital elevation models (Bray et al., 2012). We find that the depths of craters on Titan are generally within the range of depths observed on Ganymede, but several hundreds of meters shallower than the average (Fig. 1). A statistical comparison between the two data sets suggests that it is extremely unlikely that Titan’s craters were selected from the depth distribution of fresh craters on Ganymede, and that is it much more probable that the relative depths of Titan are uniformly distributed between ‘fresh’ and ‘completely infilled’. This is consistent with an infilling process that varies linearly with time, such as aeolian infilling. Figure 1: Depth of

  17. Calibration Standards for Surface Topography Measuring Systems down to Nanometric Range

    DEFF Research Database (Denmark)

    Trumpold, H.; De Chiffre, Leonardo; Andreasen, Jan Lasson

    compression and injection moulded plastic negatives and Ni-negatives have been made from which again Ni-positives were produced. The replication processes showed negligible deviations from the Pt and Pa values compared to the primary standards. An important prerequisite is the cleanliness of the surfaces......Background For the precise and accurate measurement of surface topography a whole range of surface detection systems is available. With their application in research and production problems arise due to the lack of traceable standard artefacts for the instrument calibration in X, Y and Z directions...... and for the calibration of filters. Existing ISO standards on calibration specimens are inadequate and limited in that they only cover contacting instruments and only partially the measuring ranges for these instruments. The whole range of non-contacting instruments are not covered despite their increasing use...

  18. Smoking Topography in Korean American and White Men: Preliminary Findings

    Science.gov (United States)

    Chung, Sangkeun; Kim, Sun S; Kini, Nisha; Fang, Hua J; Kalman, David; Ziedonis, Douglas M.

    2013-01-01

    Introduction This is the first study of Korean Americans’ smoking behavior using a topography device. Korean American men smoke at higher rates than the general U.S. population. Methods Korean American and White men were compared based on standard tobacco assessment and smoking topography measures. They smoked their preferred brand of cigarettes ad libitum with a portable smoking topography device for 24 hours. Results Compared to White men (N = 26), Korean American men (N = 27) were more likely to smoke low nicotine-yield cigarettes (p < 0.001) and have lower Fagerstrom nicotine dependence scores (p = 0.04). Koreans smoked fewer cigarettes with the device (p = 0.01) than Whites. Controlling for the number of cigarettes smoked, Koreans smoked with higher average puff flows (p = 0.05), greater peak puff flows (p = 0.02), and shorter interpuff intervals (p < 0.001) than Whites. Puff counts, puff volumes, and puff durations did not differ between the two groups. Conclusions This study offers preliminary insight into unique smoking patterns among Korean American men who are likely to smoke low nicotine-yield cigarettes. We found that Korean American men compensated their lower number and low nicotine-yield cigarettes by smoking more frequently with greater puff flows than White men, which may suggest exposures to similar amounts of nicotine and harmful tobacco toxins by both groups. Clinicians will need to consider in identifying and treating smokers in a mutually aggressive manner, irrespective of cigarette type and number of cigarette smoked per day. PMID:24068611

  19. Topography and biological noise determine acoustic detectability on coral reefs

    KAUST Repository

    Cagua, Edgar F.

    2013-08-19

    Acoustic telemetry is an increasingly common tool for studying the movement patterns, behavior and site fidelity of marine organisms, but to accurately interpret acoustic data, the variability, periodicity and range of detectability between acoustic tags and receivers must be understood. The relative and interactive effects of topography with biological and environmental noise have not been quantified on coral reefs. We conduct two long-term range tests (1- and 4-month duration) on two different reef types in the central Red Sea to determine the relative effect of distance, depth, topography, time of day, wind, lunar phase, sea surface temperature and thermocline on detection probability. Detectability, as expected, declines with increasing distance between tags and receivers, and we find average detection ranges of 530 and 120 m, using V16 and V13 tags, respectively, but the topography of the reef can significantly modify this relationship, reducing the range by ~70 %, even when tags and receivers are in line-of-sight. Analyses that assume a relationship between distance and detections must therefore be used with care. Nighttime detection range was consistently reduced in both locations, and detections varied by lunar phase in the 4-month test, suggesting a strong influence of biological noise (reducing detection probability up to 30 %), notably more influential than other environmental noises, including wind-driven noise, which is normally considered important in open-water environments. Analysis of detections should be corrected in consideration of the diel patterns we find, and range tests or sentinel tags should be used for more than 1 month to quantify potential changes due to lunar phase. Some studies assume that the most usual factor limiting detection range is weather-related noise; this cannot be extrapolated to coral reefs. © 2013 Springer-Verlag Berlin Heidelberg.

  20. Surface topography and ultrastructural changes of mucinous carcinoma breast cells.

    Science.gov (United States)

    Voloudakis, G E; Baltatzis, G E; Agnantis, N J; Arnogianaki, N; Misitzis, J; Voloudakis-Baltatzis, I

    2007-01-01

    Mucinous carcinoma of the breast (MCB) is histologically classified into 2 groups: (1) pure MCB and (2) mixed MCB. Pure MCB carries a better diagnosis than mixed MCB. This research relates to the cell surface topography and ultrastructure of the cells in the above cases and aims to find the differences between them, by means of two methods: scanning electron microscopy (SEM) and transmission electron microscopy (TEM). For the SEM examination, it was necessary to initially culture the MCB tissues and then proceed with the usual SEM method. In contrast, for the TEM technique, MCB tissues were initially fixed followed by the classic TEM method. The authors found the topography of pure MCB cases to be without nodes. The cell membrane was smooth, with numerous pores and small ruffles that covered the entire cell. The ultrastructural appearance of the same cases was with a normal cell membrane containing abundant collagen fibers. They also had many small vesicles containing mucin as well as secretory droplets. In contrast the mixed MCB had a number of lymph nodes and their cell surface topography showed stronger changes such as microvilli, numerous blebs, ruffles and many long projections. Their ultrastructure showed very long microvilli with large cytoplasmic inclusions and extracellular mucin collections, electron-dense material vacuoles, and many important cytoplasmic organelles. An important fact is that mixed MCB also contains areas of infiltrating ductal carcinoma. These cells of the cytoplasmic organelles are clearly responsible for the synthesis, storage, and secretion of the characteristic mucin of this tumor type. Evidently, this abnormal mucin production and the abundance of secretory granules along with the long projections observed in the topographical structure might be responsible for transferring tumor cells to neighboring organs, thus being responsible for metastatic disease.