Science.gov

Sample records for 30-meter 99-foot spatial

  1. Feasibility of a 30-meter space based laser transmitter

    NASA Technical Reports Server (NTRS)

    Berggren, R. R.; Lenertz, G. E.

    1975-01-01

    A study was made of the application of large expandable mirror structures in future space missions to establish the feasibility and define the potential of high power laser systems for such applications as propulsion and power transmission. Application of these concepts requires a 30-meter diameter, diffraction limited mirror for transmission of the laser energy. Three concepts for the transmitter are presented. These concepts include consideration of continuous as well as segmented mirror surfaces and the major stow-deployment categories of inflatable, variable geometry and assembled-in-space structures. The mirror surface for each concept would be actively monitored and controlled to maintain diffraction limited performance at 10.6 microns during operation. The proposed mirror configurations are based on existing aerospace state-of-the-art technology. The assembled-in-space concept appears to be the most feasible, at this time.

  2. A 1-degree FOV 30-meter telescope concept revisited

    NASA Astrophysics Data System (ADS)

    Barden, Samuel C.; McGrath, Andrew J.; Gillingham, Peter R.; Harmer, Charles F.

    2004-10-01

    The science case for wide fields on ELTs is well developed and justifies the implementation of 20 arc-minute and larger fields-of-view with seeing-limited performance on a 20 to 30-meter telescope. However, the practical implementation of a wide field can prove to be challenging with classical telescope design when low-thermal emissivity performance is also being optimized. Segmented mirrors assemblies need not be full aperture, axially symmetric structures. Space for secondary, tertiary, and quaternary mirror support structures that do not cross the optical path can be achieved with off-axis mirror assemblies. Barden, Harmer, Claver, and Dey described a 4-mirror, 1-degree FOV 30-meter telescope. We take that concept further with an off-axis approach. Three conic mirrors are required to produce excellent image quality in the 1-degree FOV (diffraction limited across the central few arc-minutes, better than 0.3" imaging performance at the edge of the field). A flat quaternary mirror is utilized both as a beam steering mirror to different instrument ports on the lower side of the telescope and as an adaptive mirror for wind-buffeting and possible ground layer AO correction. The final f/2.2 focal ratio allows the use of an echidna-style fiber positioner for very dense target field acquisition. Extreme AO and Ground Layer AO ports can both be implemented as well. Diffraction characteristics may possibly be improved given the lack of a spider mount for the secondary mirror but will be elliptical rather than circular.

  3. 49 CFR 210.31 - Operation standards (stationary locomotives at 30 meters).

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Operation standards (stationary locomotives at 30 meters). 210.31 Section 210.31 Transportation Other Regulations Relating to Transportation (Continued... REGULATIONS Inspection and Testing § 210.31 Operation standards (stationary locomotives at 30 meters). (a)...

  4. 49 CFR 210.31 - Operation standards (stationary locomotives at 30 meters).

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Operation standards (stationary locomotives at 30 meters). 210.31 Section 210.31 Transportation Other Regulations Relating to Transportation (Continued... REGULATIONS Inspection and Testing § 210.31 Operation standards (stationary locomotives at 30 meters). (a)...

  5. ASTER-Derived 30-Meter-Resolution Digital Elevation Models of Afghanistan

    USGS Publications Warehouse

    Chirico, Peter G.; Warner, Michael B.

    2007-01-01

    INTRODUCTION The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is an imaging instrument aboard the Terra satellite, launched on December 19, 1999, as part of the National Aeronautics and Space Administration's (NASA) Earth Observing System (EOS). The ASTER sensor consists of three subsystems: the visible and near infrared (VNIR), the shortwave infrared (SWIR), and the thermal infrared (TIR), each with a different spatial resolution (VNIR, 15 meters; SWIR, 30 meters, TIR 90 meters). The VNIR system has the capability to generate along-track stereo images that can be used to create digital elevation models (DEMs) at 30-meter resolution. Currently, the only available DEM dataset for Afghanistan is the 90-meter-resolution Shuttle Radar Topography Mission (SRTM) data. This dataset is appropriate for macroscale DEM analysis and mapping. However, ASTER provides a low cost opportunity to generate higher resolution data. For this publication, study areas were identified around populated areas and areas where higher resolution elevation data were desired to assist in natural resource assessments. The higher resolution fidelity of these DEMs can also be used for other terrain analysis including landform classification and geologic structure analysis. For this publication, ASTER scenes were processed and mosaicked to generate 36 DEMs which were created and extracted using PCI Geomatics' OrthoEngine 3D Stereo software. The ASTER images were geographically registered to Landsat data with at least 15 accurate and well distributed ground control points with a root mean square error (RMSE) of less that one pixel (15 meters). An elevation value was then assigned to each ground control point by extracting the elevation from the 90-meter SRTM data. The 36 derived DEMs demonstrate that the software correlated on nearly flat surfaces and smooth slopes accurately. Larger errors occur in cloudy and snow-covered areas, lakes, areas with steep slopes, and

  6. Development and Implementation of the DTOPLATS-MP land surface model over the Continental US at 30 meters

    NASA Astrophysics Data System (ADS)

    Chaney, N.; Wood, E. F.

    2014-12-01

    The increasing accessibility of high-resolution land data (< 100 m) and high performance computing allows improved parameterizations of subgrid hydrologic processes in macroscale land surface models. Continental scale fully distributed modeling at these spatial scales is possible; however, its practicality for operational use is still unknown due to uncertainties in input data, model parameters, and storage requirements. To address these concerns, we propose a modeling framework that provides the spatial detail of a fully distributed model yet maintains the benefits of a semi-distributed model. In this presentation we will introduce DTOPLATS-MP, a coupling between the NOAH-MP land surface model and the Dynamic TOPMODEL hydrologic model. This new model captures a catchment's spatial heterogeneity by clustering high-resolution land datasets (soil, topography, and land cover) into hundreds of hydrologic similar units (HSUs). A prior DEM analysis defines the connections between each HSU. At each time step, the 1D land surface model updates each HSU; the HSUs then interact laterally via the subsurface and surface. When compared to the fully distributed form of the model, this framework allows a significant decrease in computation and storage while providing most of the same information and enabling parameter transferability. As a proof of concept, we will show how this new modeling framework can be run over CONUS at a 30-meter spatial resolution. For each catchment in the WBD HUC-12 dataset, the model is run between 2002 and 2012 using available high-resolution continental scale land and meteorological datasets over CONUS (dSSURGO, NLCD, NED, and NCEP Stage IV). For each catchment, the model is run with 1000 model parameter sets obtained from a Latin hypercube sample. This exercise will illustrate the feasibility of running the model operationally at continental scales while accounting for model parameter uncertainty.

  7. POLARIS: A 30-meter probabilistic soil series map of the contiguous United States

    USGS Publications Warehouse

    Chaney, Nathaniel W; Wood, Eric F; McBratney, Alexander B; Hempel, Jonathan W; Nauman, Travis; Brungard, Colby W.; Odgers, Nathan P

    2016-01-01

    A new complete map of soil series probabilities has been produced for the contiguous United States at a 30 m spatial resolution. This innovative database, named POLARIS, is constructed using available high-resolution geospatial environmental data and a state-of-the-art machine learning algorithm (DSMART-HPC) to remap the Soil Survey Geographic (SSURGO) database. This 9 billion grid cell database is possible using available high performance computing resources. POLARIS provides a spatially continuous, internally consistent, quantitative prediction of soil series. It offers potential solutions to the primary weaknesses in SSURGO: 1) unmapped areas are gap-filled using survey data from the surrounding regions, 2) the artificial discontinuities at political boundaries are removed, and 3) the use of high resolution environmental covariate data leads to a spatial disaggregation of the coarse polygons. The geospatial environmental covariates that have the largest role in assembling POLARIS over the contiguous United States (CONUS) are fine-scale (30 m) elevation data and coarse-scale (~ 2 km) estimates of the geographic distribution of uranium, thorium, and potassium. A preliminary validation of POLARIS using the NRCS National Soil Information System (NASIS) database shows variable performance over CONUS. In general, the best performance is obtained at grid cells where DSMART-HPC is most able to reduce the chance of misclassification. The important role of environmental covariates in limiting prediction uncertainty suggests including additional covariates is pivotal to improving POLARIS' accuracy. This database has the potential to improve the modeling of biogeochemical, water, and energy cycles in environmental models; enhance availability of data for precision agriculture; and assist hydrologic monitoring and forecasting to ensure food and water security.

  8. Towards global scale coastal flood hazard in Delta Cities with 30-meter SRTM and 3D_i

    NASA Astrophysics Data System (ADS)

    Winsemius, Hessel; Verhoeven, Govert; Van Leeuwen, Elgard; Van der Klis, Hanneke; Van Wesenbeeck, Bregje; Cumiskey, Lydia; Verlaan, Martin; Muis, Sanne; Ward, Philip; Kwadijk, Jaap

    2015-04-01

    Most attempts to globally simulate inundation at the land-coast interface rely on maximum flood level GIS-based flood spreading models. These are generally not mass conservative, do not account for the genesis of tidal and surges in time, and do not include channel geometry and surface roughness. Furthermore, these methods cannot be used to study the impact of hazard reducing intervention measures that increase roughness at the land-coast interface. These measures include breakwaters and coastal ecosystems, such as mangrove forests and shell fish and coral reefs. Recently, new datasets and models are becoming available that allow us to greatly improve simulation of inundation in global deltas in a rapid and computationally feasible way. In this poster we demonstrate the feasibility of modelling all global deltas with strongly urbanised areas explicitly using these datasets and models. This will allow initiatives such as the 100 resilient cities (Rockefeller foundation) and the 'making cities resilient' campaign (UNISDR) to tackle the issue of coastal flood risk efficiently. We propose to use the following materials: A subgrid enabling 1D-2D model code Outputs from a global tidal and storm surge model Open topographical data We demonstrate the feasibility of this approach by modelling the Mississippi delta with: a) a lidar derived topography dataset (www.gis.ms.gov/); and b) the recently released 30 meter elevation dataset from the Shuttle Radar Topography Mission. We use the new 3Di subgrid code to rapidly schematise the vast delta area with a quadtree mesh. We force the model at the boundaries with water level estimates during the Katrina cyclone. We invite scientists working on global scale inundation modelling to visit our poster in order to discuss possibilities and limitations of the proposed methods related to model codes, data quality and calibration.

  9. Assessing Landscape Connectivity and River Water Quality Changes Using an 8-Day, 30-Meter Land Cover Dataset

    NASA Astrophysics Data System (ADS)

    Kamarinas, I.; Julian, J.; Owsley, B.; de Beurs, K.; Hughes, A.

    2014-12-01

    Water quality is dictated by interactions among geomorphic processes, vegetation characteristics, weather patterns, and anthropogenic land uses over multiple spatio-temporal scales. In order to understand how changes in climate and land use impact river water quality, a suite of data with high temporal resolution over a long period is needed. Further, all of this data must be analyzed with respect to connectivity to the river, thus requiring high spatial resolution data. Here, we present how changes in climate and land use over the past 25 years have affected water quality in the 268 sq. km Hoteo River catchment in New Zealand. Hydro-climatic data included daily solar radiation, temperature, soil moisture, rainfall, drought indices, and runoff at 5-km resolution. Land cover changes were measured every 8 days at 30-m resolution by fusing Landsat and MODIS satellite imagery. Water quality was assessed using 15-min turbidity (2011-2014) and monthly data for a suite of variables (1990-2014). Watershed connectivity was modeled using a corrected 15-m DEM and a high-resolution drainage network. Our analyses revealed that this catchment experiences cyclical droughts which, when combined with intense land uses such as livestock grazing and plantation forest harvesting, leaves many areas in the catchment disturbed (i.e. exposed soil) that are connected to the river through surface runoff. As a result, flow-normalized turbidity was elevated during droughts and remained relatively low during wet periods. For example, disturbed land area decreased from 9% to 4% over 2009-2013, which was a relatively wet period. During the extreme drought of 2013, disturbed area increased to 6% in less than a year due mainly to slow pasture recovery after heavy stocking rates. The relationships found in this study demonstrate that high spatiotemporal resolution land cover datasets are very important to understanding the interactions between landscape and climate, and how these interactions

  10. Assessment of a Near-Global 30-meter Resolution DEM Derived from the Publicly Available SRTM Data Set for Use in Orthorectification of Satellite SAR Imagery

    NASA Astrophysics Data System (ADS)

    McDonald, K. C.; Chapman, B.; Podest, E.; Jimenez, A.

    2007-12-01

    The Shuttle Radar Topography Mission (SRTM) utilized an interferometric synthetic aperture radar (InSAR) flown onboard the space shuttle Endeavour to obtain high resolution elevation data of Earth's land surface. Virtually all land surface between +/- 60 degrees latitude was mapped. Regions within these bounds contain some data gaps but this represents less than 0.2 % of the coverage. Standard publicly-available data sets from SRTM include a 3 arc-second (~90 meter) resolution Digital Elevation Model (DEM) with absolute average global vertical accuracy of approximately 4 to 5 meters. A 1 arc-second (~30 meter) resolution DEM has also been developed, but only the portion of the data set covering the United States is publicly available. The finished version of these products has been edited for pixel-level errors and delineation of coastlines and water bodies, although some data voids are still present. Utilizing such DEMs of appropriate resolution in a common framework with satellite synthetic aperture radar (SAR) data allows robust ortho-rectification and geo-referencing of the SAR data sets. We have derived a 1 arc-second resolution DEM over the entire domain of the SRTM coverage using a 3- dimensional interpolation scheme applied to the 3 arc-second SRTM DEM. Development of this product involves (1) translation of SRTM products into the WGS84 datum, (2) interpolation of the lower resolution DEMs to 1 arc- second, and (3) assembly of the global-scale 1 arc-second DEM. We assess effectiveness of this interpolation scheme through comparative statistical analysis of the 3 arc-second finished product, the 1 arc-second finished product, and the 1 arc-second interpolated product over selected test regions within the USA where all products are available. Comparisons are also made to standard GTOPO30 products for regions inside and outside of the USA. Comparisons are presented for regions representative of gentle and complex terrain. Ortho-rectification of SAR data such

  11. Computer Programs to Display and Modify Data in Geographic Coordinates and Methods to Transfer Positions to and from Maps, with Applications to Gravity Data Processing, Global Positioning Systems, and 30-Meter Digital Elevation Models

    USGS Publications Warehouse

    Plouff, Donald

    1998-01-01

    Computer programs were written in the Fortran language to process and display gravity data with locations expressed in geographic coordinates. The programs and associated processes have been tested for gravity data in an area of about 125,000 square kilometers in northwest Nevada, southeast Oregon, and northeast California. This report discusses the geographic aspects of data processing. Utilization of the programs begins with application of a template (printed in PostScript format) to transfer locations obtained with Global Positioning Systems to and from field maps and includes a 5-digit geographic-based map naming convention for field maps. Computer programs, with source codes that can be copied, are used to display data values (printed in PostScript format) and data coverage, insert data into files, extract data from files, shift locations, test for redundancy, and organize data by map quadrangles. It is suggested that 30-meter Digital Elevation Models needed for gravity terrain corrections and other applications should be accessed in a file search by using the USGS 7.5-minute map name as a file name, for example, file '40117_B8.DEM' contains elevation data for the map with a southeast corner at lat 40? 07' 30' N. and lon 117? 52' 30' W.

  12. EnviroAtlas - Percentage of stream and water body shoreline lengths within 30 meters of >= 5% or >= 15% impervious cover by 12-Digit HUC for the Conterminous United States

    EPA Pesticide Factsheets

    This EnviroAtlas dataset shows the percentages of stream and water body shoreline lengths within 30 meters of impervious cover by 12-digit Hydrologic Unit (HUC) subwatershed in the contiguous U.S. Impervious cover alters the hydrologic behavior of streams and water bodies, promoting increased storm water runoff and lower stream flow during periods in between rainfall events. Impervious cover also promotes increased pollutant loads in receiving waters and degraded streamside habitat. This dataset shows were impervious cover occurs close to streams and water bodies, where it is likely to have a greater adverse impact on receiving waters. This dataset was produced by the US EPA to support research and online mapping activities related to the EnviroAtlas. EnviroAtlas (https://www.epa.gov/enviroatlas) allows the user to interact with a web-based, easy-to-use, mapping application to view and analyze multiple ecosystem services for the contiguous United States. The dataset is available as downloadable data (https://edg.epa.gov/data/Public/ORD/EnviroAtlas) or as an EnviroAtlas map service. Additional descriptive information about each attribute in this dataset can be found in its associated EnviroAtlas Fact Sheet (https://www.epa.gov/enviroatlas/enviroatlas-fact-sheets).

  13. Feasibility of a 30-Meter Space Based Laser Transmitter

    DTIC Science & Technology

    1975-10-01

    surface, Fig. 37, was produced using an unequal path, Twyman -Green interferometer . The contour plot of the surface errors results from a computer...here that the resulting data are at least as accurate as those obtained by a conventional Twyman -Green type of interferometer . In fact, the common...is well developed. It is concluded that error sensing will not limit the feasibility of a large mirror. Real-time interferometers which provide a

  14. Characteristics of the spatial pattern of the dengue vector, Aedes aegypti, in Iquitos, Peru.

    PubMed

    Getis, Arthur; Morrison, Amy C; Gray, Kenneth; Scott, Thomas W

    2003-11-01

    We determine the spatial pattern of Aedes aegypti and the containers in which they develop in two neighborhoods of the Amazonian city of Iquitos, Peru. Four variables were examined: adult Ae. aegypti, pupae, containers positive for larvae or pupae, and all water-holding containers. Adults clustered strongly within houses and weakly to a distance of 30 meters beyond the household; clustering was not detected beyond 10 meters for positive containers or pupae. Over short periods of time restricted flight range and frequent blood-feeding behavior of Ae. aegypti appear to be underlying factors in the clustering patterns of human dengue infections. Permanent, consistently infested containers (key premises) were not major producers of Ae. aegypti, indicating that larvaciding strategies by themselves may be less effective than reduction of mosquito development sites by source reduction and education campaigns. We conclude that entomologic risk of human dengue infection should be assessed at the household level at frequent time intervals.

  15. Spatial cognition

    NASA Technical Reports Server (NTRS)

    Kaiser, Mary Kister; Remington, Roger

    1988-01-01

    Spatial cognition is the ability to reason about geometric relationships in the real (or a metaphorical) world based on one or more internal representations of those relationships. The study of spatial cognition is concerned with the representation of spatial knowledge, and our ability to manipulate these representations to solve spatial problems. Spatial cognition is utilized most critically when direct perceptual cues are absent or impoverished. Examples are provided of how human spatial cognitive abilities impact on three areas of space station operator performance: orientation, path planning, and data base management. A videotape provides demonstrations of relevant phenomena (e.g., the importance of orientation for recognition of complex, configural forms). The presentation is represented by abstract and overhead visuals only.

  16. Spatial Displays and Spatial Instruments

    NASA Technical Reports Server (NTRS)

    Ellis, Stephen R. (Editor); Kaiser, Mary K. (Editor); Grunwald, Arthur J. (Editor)

    1989-01-01

    The conference proceedings topics are divided into two main areas: (1) issues of spatial and picture perception raised by graphical electronic displays of spatial information; and (2) design questions raised by the practical experience of designers actually defining new spatial instruments for use in new aircraft and spacecraft. Each topic is considered from both a theoretical and an applied direction. Emphasis is placed on discussion of phenomena and determination of design principles.

  17. A Microthermal Device for Measuring the Spatial Power Spectrum of Atmospheric Turbulence

    NASA Astrophysics Data System (ADS)

    Turner, Jonathan; McGraw, J.; Zimmer, P.; Williams, T.; Claver, C.; Krabbendam, V.; Wiecha, O.; Andrew, J.; Warner, M.

    2009-01-01

    The Measurement Astrophysics group at UNM designed and built a novel microthermal device for the purpose of characterizing atmospheric turbulence at astronomical observatories. This instrument is based on the Wheatstone bridge and uses fine wire tungsten filaments as resistance temperature detectors. The device is designed to work in two data taking modes: with a horizontal array of microthermal sensors, or with a vertical array of sensors. In horizontal mode differential measurements are made between adjacent sensors, then these measurements are combined to recover the differences between all non-adjacent sensor pairs. The result of these measurements is microthermal data over many independent baselines which comprise a spatial spectrum of turbulence. The measured turbulent spectra are then fit to standard turbulence models which yield estimates of the outer scale of turbulence and the slope of the power spectra. Measurements in horizontal mode are made with 14 sensors over baselines of up to 30 meters. In addition probes can be repositioned to provide additional baselines. In vertical mode the device operates as microthermals traditionally have in the past: differential measurements are made between a pair of resistance temperature detectors. Sensor pairs are suspended at different heights above the ground allowing measurement of atmospheric turbulence as a function of altitude. Measurements in vertical mode are made with 14 sensor pairs which can be elevated up to 30 meters above ground. Data were taken with the device in a variety of test configurations, and the device is being used in a site testing campaign at Cerro Pachon. We will present the design, prototyping, and testing of this instrument as well as preliminary results from our campaign on Cerro Pachon.

  18. Operating experience with the southwire 30-meter high-temperature superconducting power cable

    NASA Astrophysics Data System (ADS)

    Stovall, J. P.; Lue, J. W.; Demko, J. A.; Fisher, P. W.; Gouge, M. J.; Hawsey, R. A.; Armstrong, J. W.; Hughey, R. L.; Lindsay, D. T.; Roden, M. L.; Sinha, U. K.; Tolbert, J. C.

    2002-05-01

    Southwire Company is operating a high-temperature superconducting (HTS) cable system at its corporate headquarters. The 30-m long, 3-phase cable system is powering three Southwire manufacturing plants and is rated at 12.4-kV, 1250-A, 60-Hz. Cooling is provided by a pressurized liquid nitrogen system operating at 70-80 K. The cables were energized on January 5, 2000 for on-line testing and operation and in April 2000 were placed into extended service. As of June 1, 2001, the HTS cables have provided 100% of the customer load for 8000 hours. The cryogenic system has been in continuous operation since November 1999. The HTS cable system has not been the cause of any power outages to the average 20 MW industrial load served by the cable. The cable has been exposed to short-circuit currents caused by load-side faults without damage. Based upon field measurements described herein, the cable critical current-a key performance parameter-remains the same and has not been affected by the hours of real-world operation, further proving the viability of this promising technology.

  19. Regional correlations of VS30 averaged over depths less than and greater than 30 meters

    USGS Publications Warehouse

    Boore, David M.; Thompson, Eric M.; Cadet, Héloïse

    2011-01-01

    Using velocity profiles from sites in Japan, California, Turkey, and Europe, we find that the time-averaged shear-wave velocity to 30 m (VS30), used as a proxy for site amplification in recent ground-motion prediction equations (GMPEs) and building codes, is strongly correlated with average velocities to depths less than 30 m (VSz, with z being the averaging depth). The correlations for sites in Japan (corresponding to the KiK-net network) show that VSz is systematically larger for a given VSz than for profiles from the other regions. The difference largely results from the placement of the KiK-net station locations on rock and rocklike sites, whereas stations in the other regions are generally placed in urban areas underlain by sediments. Using the KiK-net velocity profiles, we provide equations relating VS30 to VSz for z ranging from 5 to 29 m in 1-m increments. These equations (and those for California velocity profiles given in Boore, 2004b) can be used to estimate VS30 from VSz for sites in which velocity profiles do not extend to 30 m. The scatter of the residuals decreases with depth, but, even for an averaging depth of 5 m, a variation in logVS30 of ±1 standard deviation maps into less than a 20% uncertainty in ground motions given by recent GMPEs at short periods. The sensitivity of the ground motions to VS30 uncertainty is considerably larger at long periods (but is less than a factor of 1.2 for averaging depths greater than about 20 m). We also find that VS30 is correlated with VSz for z as great as 400 m for sites of the KiK-net network, providing some justification for using VS30 as a site-response variable for predicting ground motions at periods for which the wavelengths far exceed 30 m.

  20. Large Steel Tank Fails and Rockets to Height of 30 meters - Rupture Disc Installed Incorrectly.

    PubMed

    Hedlund, Frank H; Selig, Robert S; Kragh, Eva K

    2016-06-01

    At a brewery, the base plate-to-shell weld seam of a 90-m(3) vertical cylindrical steel tank failed catastrophically. The 4 ton tank "took off" like a rocket leaving its contents behind, and landed on a van, crushing it. The top of the tank reached a height of 30 m. The internal overpressure responsible for the failure was an estimated 60 kPa. A rupture disc rated at < 50 kPa provided overpressure protection and thus prevented the tank from being covered by the European Pressure Equipment Directive. This safeguard failed and it was later discovered that the rupture disc had been installed upside down. The organizational root cause of this incident may be a fundamental lack of appreciation of the hazards of large volumes of low-pressure compressed air or gas. A contributing factor may be that the standard piping and instrumentation diagram (P&ID) symbol for a rupture disc may confuse and lead to incorrect installation. Compressed air systems are ubiquitous. The medium is not toxic or flammable. Such systems however, when operated at "slight overpressure" can store a great deal of energy and thus constitute a hazard that ought to be addressed by safety managers.

  1. 49 CFR 210.31 - Operation standards (stationary locomotives at 30 meters).

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... locomotive has attained the normal cooling water operating temperature as prescribed by the locomotive... prescribed in paragraph (a)(2) of this section, the A-weighted sound level reading in decibels shall be... A-weighted sound level reading in decibels that is observed during the 30-second period of...

  2. 49 CFR 210.31 - Operation standards (stationary locomotives at 30 meters).

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... locomotive has attained the normal cooling water operating temperature as prescribed by the locomotive... prescribed in paragraph (a)(2) of this section, the A-weighted sound level reading in decibels shall be... A-weighted sound level reading in decibels that is observed during the 30-second period of...

  3. 49 CFR 210.31 - Operation standards (stationary locomotives at 30 meters).

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... locomotive has attained the normal cooling water operating temperature as prescribed by the locomotive... prescribed in paragraph (a)(2) of this section, the A-weighted sound level reading in decibels shall be... A-weighted sound level reading in decibels that is observed during the 30-second period of...

  4. Spatial Encounters: Exercises in Spatial Awareness.

    ERIC Educational Resources Information Center

    New Mexico Univ., Albuquerque.

    This series of activities on spatial relationships was designed to help users acquire the skills of spatial visualization and orientation and to improve their effectiveness in applying those skills. The series contains an introduction to spatial orientation with several self-directed activities to help improve that skill. It also contains seven…

  5. Shifting Patterns of Aedes aegypti Fine Scale Spatial Clustering in Iquitos, Peru

    PubMed Central

    LaCon, Genevieve; Morrison, Amy C.; Astete, Helvio; Stoddard, Steven T.; Paz-Soldan, Valerie A.; Elder, John P.; Halsey, Eric S.; Scott, Thomas W.; Kitron, Uriel; Vazquez-Prokopec, Gonzalo M.

    2014-01-01

    Background Empiric evidence shows that Aedes aegypti abundance is spatially heterogeneous and that some areas and larval habitats produce more mosquitoes than others. There is a knowledge gap, however, with regards to the temporal persistence of such Ae. aegypti abundance hotspots. In this study, we used a longitudinal entomologic dataset from the city of Iquitos, Peru, to (1) quantify the spatial clustering patterns of adult Ae. aegypti and pupae counts per house, (2) determine overlap between clusters, (3) quantify the temporal stability of clusters over nine entomologic surveys spaced four months apart, and (4) quantify the extent of clustering at the household and neighborhood levels. Methodologies/Principal Findings Data from 13,662 household entomological visits performed in two Iquitos neighborhoods differing in Ae. aegypti abundance and dengue virus transmission was analyzed using global and local spatial statistics. The location and extent of Ae. aegypti pupae and adult hotspots (i.e., small groups of houses with significantly [p<0.05] high mosquito abundance) were calculated for each of the 9 entomologic surveys. The extent of clustering was used to quantify the probability of finding spatially correlated populations. Our analyses indicate that Ae. aegypti distribution was highly focal (most clusters do not extend beyond 30 meters) and that hotspots of high vector abundance were common on every survey date, but they were temporally unstable over the period of study. Conclusions/Significance Our findings have implications for understanding Ae. aegypti distribution and for the design of surveillance and control activities relying on household-level data. In settings like Iquitos, where there is a relatively low percentage of Ae. aegypti in permanent water-holding containers, identifying and targeting key premises will be significantly challenged by shifting hotspots of Ae. aegypti infestation. Focusing efforts in large geographic areas with historically

  6. Spatial attention systems in spatial neglect.

    PubMed

    Karnath, Hans-Otto

    2015-08-01

    It has been established that processes relating to 'spatial attention' are implemented at cortical level by goal-directed (top-down) and stimulus-driven (bottom-up) networks. Spatial neglect in brain-damaged individuals has been interpreted as a distinguished exemplar for a disturbance of these processes. The present paper elaborates this assumption. Functioning of the two attentional networks seem to dissociate in spatial neglect; behavioral studies of patients' orienting and exploration behavior point to a disturbed stimulus-driven but preserved goal-directed attention system. When a target suddenly appears somewhere in space, neglect patients demonstrate disturbed detection and orienting if it is located in contralesional direction. In contrast, if neglect patients explore a scene with voluntarily, top-down controlled shifts of spatial attention, they perform movements that are oriented into all spatial directions without any direction-specific disturbances. The paper thus argues that not the top-down control of spatial attention itself, rather a body-related matrix on top of which this process is executed, seems affected. In that sense, the traditional role of spatial neglect as a stroke model for 'spatial attention' requires adjustment. Beyond its insights into the human stimulus-driven attentional system, the disorder most notably provides vistas in how our brain encodes topographical information and organizes spatially oriented action - including the top-down control of spatial attention - in relation to body position.

  7. Approximate spatial reasoning

    NASA Technical Reports Server (NTRS)

    Dutta, Soumitra

    1988-01-01

    A model for approximate spatial reasoning using fuzzy logic to represent the uncertainty in the environment is presented. Algorithms are developed which can be used to reason about spatial information expressed in the form of approximate linguistic descriptions similar to the kind of spatial information processed by humans. Particular attention is given to static spatial reasoning.

  8. Influence of Elevation Data Resolution on Spatial Prediction of Colluvial Soils in a Luvisol Region

    PubMed Central

    Penížek, Vít; Zádorová, Tereza; Kodešová, Radka; Vaněk, Aleš

    2016-01-01

    The development of a soil cover is a dynamic process. Soil cover can be altered within a few decades, which requires updating of the legacy soil maps. Soil erosion is one of the most important processes quickly altering soil cover on agriculture land. Colluvial soils develop in concave parts of the landscape as a consequence of sedimentation of eroded material. Colluvial soils are recognised as important soil units because they are a vast sink of soil organic carbon. Terrain derivatives became an important tool in digital soil mapping and are among the most popular auxiliary data used for quantitative spatial prediction. Prediction success rates are often directly dependent on raster resolution. In our study, we tested how raster resolution (1, 2, 3, 5, 10, 20 and 30 meters) influences spatial prediction of colluvial soils. Terrain derivatives (altitude, slope, plane curvature, topographic position index, LS factor and convergence index) were calculated for the given raster resolutions. Four models were applied (boosted tree, neural network, random forest and Classification/Regression Tree) to spatially predict the soil cover over a 77 ha large study plot. Models training and validation was based on 111 soil profiles surveyed on a regular sampling grid. Moreover, the predicted real extent and shape of the colluvial soil area was examined. In general, no clear trend in the accuracy prediction was found without the given raster resolution range. Higher maximum prediction accuracy for colluvial soil, compared to prediction accuracy of total soil cover of the study plot, can be explained by the choice of terrain derivatives that were best for Colluvial soils differentiation from other soil units. Regarding the character of the predicted Colluvial soils area, maps of 2 to 10 m resolution provided reasonable delineation of the colluvial soil as part of the cover over the study area. PMID:27846230

  9. Providing a Spatial Context for Crop Insurance in Ethiopia: Multiscale Comparisons of Vegetation Metrics in Tigray

    NASA Astrophysics Data System (ADS)

    Mann, B. F.; Small, C.

    2014-12-01

    Weather-based index insurance projects are rapidly expanding across the developing world. Many of these projects use satellite-based observations to detect extreme weather events, which inform and trigger payouts to smallholder farmers. While most index insurance programs use precipitation measurements to determine payouts, the use of remotely sensed observations of vegetation is currently being explored. In order to use vegetation indices as a basis for payouts, it is necessary to establish a consistent relationship between the vegetation index and the health and abundance of agriculture on the ground. The accuracy with which remotely sensed vegetation indices can detect changes in agriculture depends on both the spatial scale of the agriculture and the spatial resolution of the sensor. This study analyzes the relationship between meter and decameter scale vegetation fraction estimates derived from linear spectral mixture models with a more commonly used vegetation index (NDVI, EVI) at hectometer spatial scales. In addition, the analysis incorporates land cover/land use field observations collected in Tigray Ethiopia in July 2013. . It also tests the flexibility and utility of a standardized spectral mixture model in which land cover is represented as continuous fields of rock and soil substrate (S), vegetation (V) and dark surfaces (D; water, shadow). This analysis found strong linear relationships with vegetation metrics at 1.6-meter, 30-meter and 250-meter resolutions across spectrally diverse subsets of Tigray, Ethiopia and significantly correlated relationships using the Spearman's rho statistic. The observed linear scaling has positive implications for future use of moderate resolution vegetation indices in similar landscapes; especially index insurance projects that are scaling up across the developing world using remotely-sensed environmental information.

  10. Differentiating Spatial Memory from Spatial Transformations

    ERIC Educational Resources Information Center

    Street, Whitney N.; Wang, Ranxiao Frances

    2014-01-01

    The perspective-taking task is one of the most common paradigms used to study the nature of spatial memory, and better performance for certain orientations is generally interpreted as evidence of spatial representations using these reference directions. However, performance advantages can also result from the relative ease in certain…

  11. Spatial Language Learning

    ERIC Educational Resources Information Center

    Fu, Zhengling

    2016-01-01

    Spatial language constitutes part of the basic fabric of language. Although languages may have the same number of terms to cover a set of spatial relations, they do not always do so in the same way. Spatial languages differ across languages quite radically, thus providing a real semantic challenge for second language learners. The essay first…

  12. Spatially-Heterodyned Holography

    DOEpatents

    Thomas, Clarence E [Knoxville, TN; Hanson, Gregory R [Clinton, TN

    2006-02-21

    A method of recording a spatially low-frequency heterodyne hologram, including spatially heterodyne fringes for Fourier analysis, includes: splitting a laser beam into a reference beam and an object beam; interacting the object beam with an object; focusing the reference beam and the object beam at a focal plane of a digital recorder to form a spatially low-frequency heterodyne hologram including spatially heterodyne fringes for Fourier analysis; digital recording the spatially low-frequency heterodyne hologram; Fourier transforming axes of the recorded spatially low-frequency heterodyne hologram including spatially heterodyne fringes in Fourier space to sit on top of a heterodyne carrier frequency defined by an angle between the reference beam and the object beam; cutting off signals around an origin; and performing an inverse Fourier transform.

  13. 40 CFR 201.23 - Test site, weather conditions and background noise criteria for measurement at a 30 meter (100...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... rail car operations and locomotive load cell test stands. 201.23 Section 201.23 Protection of... locomotive and rail car operations and locomotive load cell test stands. (a) The standard test site shall be... contribution from the operation of the load cell, if any, including load cell contribution during test....

  14. 40 CFR 201.23 - Test site, weather conditions and background noise criteria for measurement at a 30 meter (100...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... rail car operations and locomotive load cell test stands. 201.23 Section 201.23 Protection of... locomotive and rail car operations and locomotive load cell test stands. (a) The standard test site shall be... contribution from the operation of the load cell, if any, including load cell contribution during test....

  15. 40 CFR 201.23 - Test site, weather conditions and background noise criteria for measurement at a 30 meter (100...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... rail car operations and locomotive load cell test stands. 201.23 Section 201.23 Protection of... locomotive and rail car operations and locomotive load cell test stands. (a) The standard test site shall be... contribution from the operation of the load cell, if any, including load cell contribution during test....

  16. Regional correlations of V s30 and velocities averaged over depths less than and greater than 30 meters

    USGS Publications Warehouse

    Boore, D.M.; Thompson, E.M.; Cadet, H.

    2011-01-01

    Using velocity profiles from sites in Japan, California, Turkey, and Europe, we find that the time-averaged shear-wave velocity to 30 m (V S30), used as a proxy for site amplification in recent ground-motion prediction equations (GMPEs) and building codes, is strongly correlated with average velocities to depths less than 30 m (V Sz, with z being the averaging depth). The correlations for sites in Japan (corresponding to the KiK-net network) show that V S30 is systematically larger for a given V Sz than for profiles from the other regions. The difference largely results from the placement of the KiK-net station locations on rock and rocklike sites, whereas stations in the other regions are generally placed in urban areas underlain by sediments. Using the KiK-net velocity profiles, we provide equations relating V S30 to V Sz for z ranging from 5 to 29 m in 1-m increments. These equations (and those for California velocity profiles given in Boore, 2004b) can be used to estimate V S30 from V Sz for sites in which velocity profiles do not extend to 30 m. The scatter of the residuals decreases with depth, but, even for an averaging depth of 5 m, a variation in log V S30 of 1 standard deviation maps into less than a 20% uncertainty in ground motions given by recent GMPEs at short periods. The sensitivity of the ground motions to V S30 uncertainty is considerably larger at long periods (but is less than a factor of 1.2 for averaging depths greater than about 20 m). We also find that V S30 is correlated with V Sz for z as great as 400 m for sites of the KiK-net network, providing some justification for using V S30 as a site-response variable for predicting ground motions at periods for which the wavelengths far exceed 30 m.

  17. 40 CFR 201.23 - Test site, weather conditions and background noise criteria for measurement at a 30 meter (100...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... rail car operations and locomotive load cell test stands. 201.23 Section 201.23 Protection of... locomotive and rail car operations and locomotive load cell test stands. (a) The standard test site shall be... contribution from the operation of the load cell, if any, including load cell contribution during test....

  18. 40 CFR 201.23 - Test site, weather conditions and background noise criteria for measurement at a 30 meter (100...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... rail car operations and locomotive load cell test stands. 201.23 Section 201.23 Protection of... locomotive and rail car operations and locomotive load cell test stands. (a) The standard test site shall be... contribution from the operation of the load cell, if any, including load cell contribution during test....

  19. A Key Concept: Spatial Organization

    ERIC Educational Resources Information Center

    Kostrowicki, Jerzy

    1975-01-01

    The application of geography to spatial planning is discussed. Concepts presented include the regional concept, the typological concept, and spatial structure, spatial processes, and spatial organization. For address of journal see SO 504 028. (Author/RM)

  20. Spatial capture-recapture

    USGS Publications Warehouse

    Royle, J. Andrew; Chandler, Richard B.; Sollmann, Rahel; Gardner, Beth

    2013-01-01

    Spatial Capture-Recapture provides a revolutionary extension of traditional capture-recapture methods for studying animal populations using data from live trapping, camera trapping, DNA sampling, acoustic sampling, and related field methods. This book is a conceptual and methodological synthesis of spatial capture-recapture modeling. As a comprehensive how-to manual, this reference contains detailed examples of a wide range of relevant spatial capture-recapture models for inference about population size and spatial and temporal variation in demographic parameters. Practicing field biologists studying animal populations will find this book to be a useful resource, as will graduate students and professionals in ecology, conservation biology, and fisheries and wildlife management.

  1. Suitable Site Selection of Small Dams Using Geo-Spatial Technique: a Case Study of Dadu Tehsil, Sindh

    NASA Astrophysics Data System (ADS)

    Khalil, Zahid

    2016-07-01

    Decision making about identifying suitable sites for any project by considering different parameters, is difficult. Using GIS and Multi-Criteria Analysis (MCA) can make it easy for those projects. This technology has proved to be an efficient and adequate in acquiring the desired information. In this study, GIS and MCA were employed to identify the suitable sites for small dams in Dadu Tehsil, Sindh. The GIS software is used to create all the spatial parameters for the analysis. The parameters that derived are slope, drainage density, rainfall, land use / land cover, soil groups, Curve Number (CN) and runoff index with a spatial resolution of 30m. The data used for deriving above layers include 30 meter resolution SRTM DEM, Landsat 8 imagery, and rainfall from National Centre of Environment Prediction (NCEP) and soil data from World Harmonized Soil Data (WHSD). Land use/Land cover map is derived from Landsat 8 using supervised classification. Slope, drainage network and watershed are delineated by terrain processing of DEM. The Soil Conservation Services (SCS) method is implemented to estimate the surface runoff from the rainfall. Prior to this, SCS-CN grid is developed by integrating the soil and land use/land cover raster. These layers with some technical and ecological constraints are assigned weights on the basis of suitability criteria. The pair wise comparison method, also known as Analytical Hierarchy Process (AHP) is took into account as MCA for assigning weights on each decision element. All the parameters and group of parameters are integrated using weighted overlay in GIS environment to produce suitable sites for the Dams. The resultant layer is then classified into four classes namely, best suitable, suitable, moderate and less suitable. This study reveals a contribution to decision making about suitable sites analysis for small dams using geo-spatial data with minimal amount of ground data. This suitability maps can be helpful for water resource

  2. Dyslexia and Spatial Thinking.

    ERIC Educational Resources Information Center

    Benton, Arthur L.

    1984-01-01

    Research on spatial thinking impairments, with special reference to right-left orientation, visuomotor and visuoconstructive performances, and finger recognition are examined. It is concluded that, although some dyslexic children do show spatial disabilities, there is little evidence to support the existence of a visuospatial type of developmental…

  3. Spatial Data Analysis.

    PubMed

    Banerjee, Sudipto

    2016-01-01

    With increasing accessibility to geographic information systems (GIS) software, statisticians and data analysts routinely encounter scientific data sets with geocoded locations. This has generated considerable interest in statistical modeling for location-referenced spatial data. In public health, spatial data routinely arise as aggregates over regions, such as counts or rates over counties, census tracts, or some other administrative delineation. Such data are often referred to as areal data. This review article provides a brief overview of statistical models that account for spatial dependence in areal data. It does so in the context of two applications: disease mapping and spatial survival analysis. Disease maps are used to highlight geographic areas with high and low prevalence, incidence, or mortality rates of a specific disease and the variability of such rates over a spatial domain. They can also be used to detect hot spots or spatial clusters that may arise owing to common environmental, demographic, or cultural effects shared by neighboring regions. Spatial survival analysis refers to the modeling and analysis for geographically referenced time-to-event data, where a subject is followed up to an event (e.g., death or onset of a disease) or is censored, whichever comes first. Spatial survival analysis is used to analyze clustered survival data when the clustering arises from geographical regions or strata. Illustrations are provided in these application domains.

  4. Individual Differences in Spatial Text Processing: High Spatial Ability Can Compensate for Spatial Working Memory Interference

    ERIC Educational Resources Information Center

    Meneghetti, Chiara; Gyselinck, Valerie; Pazzaglia, Francesca; De Beni, Rossana

    2009-01-01

    The present study investigates the relation between spatial ability and visuo-spatial and verbal working memory in spatial text processing. In two experiments, participants listened to a spatial text (Experiments 1 and 2) and a non-spatial text (Experiment 1), at the same time performing a spatial or a verbal concurrent task, or no secondary task.…

  5. Spatial heterogeneity in medulloblastoma.

    PubMed

    Morrissy, A Sorana; Cavalli, Florence M G; Remke, Marc; Ramaswamy, Vijay; Shih, David J H; Holgado, Borja L; Farooq, Hamza; Donovan, Laura K; Garzia, Livia; Agnihotri, Sameer; Kiehna, Erin N; Mercier, Eloi; Mayoh, Chelsea; Papillon-Cavanagh, Simon; Nikbakht, Hamid; Gayden, Tenzin; Torchia, Jonathon; Picard, Daniel; Merino, Diana M; Vladoiu, Maria; Luu, Betty; Wu, Xiaochong; Daniels, Craig; Horswell, Stuart; Thompson, Yuan Yao; Hovestadt, Volker; Northcott, Paul A; Jones, David T W; Peacock, John; Wang, Xin; Mack, Stephen C; Reimand, Jüri; Albrecht, Steffen; Fontebasso, Adam M; Thiessen, Nina; Li, Yisu; Schein, Jacqueline E; Lee, Darlene; Carlsen, Rebecca; Mayo, Michael; Tse, Kane; Tam, Angela; Dhalla, Noreen; Ally, Adrian; Chuah, Eric; Cheng, Young; Plettner, Patrick; Li, Haiyan I; Corbett, Richard D; Wong, Tina; Long, William; Loukides, James; Buczkowicz, Pawel; Hawkins, Cynthia E; Tabori, Uri; Rood, Brian R; Myseros, John S; Packer, Roger J; Korshunov, Andrey; Lichter, Peter; Kool, Marcel; Pfister, Stefan M; Schüller, Ulrich; Dirks, Peter; Huang, Annie; Bouffet, Eric; Rutka, James T; Bader, Gary D; Swanton, Charles; Ma, Yusanne; Moore, Richard A; Mungall, Andrew J; Majewski, Jacek; Jones, Steven J M; Das, Sunit; Malkin, David; Jabado, Nada; Marra, Marco A; Taylor, Michael D

    2017-04-10

    Spatial heterogeneity of transcriptional and genetic markers between physically isolated biopsies of a single tumor poses major barriers to the identification of biomarkers and the development of targeted therapies that will be effective against the entire tumor. We analyzed the spatial heterogeneity of multiregional biopsies from 35 patients, using a combination of transcriptomic and genomic profiles. Medulloblastomas (MBs), but not high-grade gliomas (HGGs), demonstrated spatially homogeneous transcriptomes, which allowed for accurate subgrouping of tumors from a single biopsy. Conversely, somatic mutations that affect genes suitable for targeted therapeutics demonstrated high levels of spatial heterogeneity in MB, malignant glioma, and renal cell carcinoma (RCC). Actionable targets found in a single MB biopsy were seldom clonal across the entire tumor, which brings the efficacy of monotherapies against a single target into question. Clinical trials of targeted therapies for MB should first ensure the spatially ubiquitous nature of the target mutation.

  6. Robustness of spatial micronetworks

    NASA Astrophysics Data System (ADS)

    McAndrew, Thomas C.; Danforth, Christopher M.; Bagrow, James P.

    2015-04-01

    Power lines, roadways, pipelines, and other physical infrastructure are critical to modern society. These structures may be viewed as spatial networks where geographic distances play a role in the functionality and construction cost of links. Traditionally, studies of network robustness have primarily considered the connectedness of large, random networks. Yet for spatial infrastructure, physical distances must also play a role in network robustness. Understanding the robustness of small spatial networks is particularly important with the increasing interest in microgrids, i.e., small-area distributed power grids that are well suited to using renewable energy resources. We study the random failures of links in small networks where functionality depends on both spatial distance and topological connectedness. By introducing a percolation model where the failure of each link is proportional to its spatial length, we find that when failures depend on spatial distances, networks are more fragile than expected. Accounting for spatial effects in both construction and robustness is important for designing efficient microgrids and other network infrastructure.

  7. Robustness of spatial micronetworks.

    PubMed

    McAndrew, Thomas C; Danforth, Christopher M; Bagrow, James P

    2015-04-01

    Power lines, roadways, pipelines, and other physical infrastructure are critical to modern society. These structures may be viewed as spatial networks where geographic distances play a role in the functionality and construction cost of links. Traditionally, studies of network robustness have primarily considered the connectedness of large, random networks. Yet for spatial infrastructure, physical distances must also play a role in network robustness. Understanding the robustness of small spatial networks is particularly important with the increasing interest in microgrids, i.e., small-area distributed power grids that are well suited to using renewable energy resources. We study the random failures of links in small networks where functionality depends on both spatial distance and topological connectedness. By introducing a percolation model where the failure of each link is proportional to its spatial length, we find that when failures depend on spatial distances, networks are more fragile than expected. Accounting for spatial effects in both construction and robustness is important for designing efficient microgrids and other network infrastructure.

  8. Spatial Light Amplifier Modulators

    NASA Technical Reports Server (NTRS)

    Eng, Sverre T.; Olsson, N. Anders

    1992-01-01

    Spatial light amplifier modulators (SLAM's) are conceptual devices that effect two-dimensional spatial modulation in optical computing and communication systems. Unlike current spatial light modulators, these provide gain. Optical processors incorporating SLAM's designed to operate in reflection or transmission mode. Each element of planar SLAM array is optical amplifier - surface-emitting diode laser. Array addressed electrically with ac modulating signals superimposed on dc bias currents supplied to lasers. SLAM device provides both desired modulation and enough optical gain to enable splitting of output signal into many optical fibers without excessive loss of power.

  9. Subsurface information for risk-sensitive urban spatial planning in Dhaka Metropolitan City, Bangladesh

    NASA Astrophysics Data System (ADS)

    Günther, Andreas; Aziz Patwary, Mohammad Abdul; Bahls, Rebecca; Asaduzzaman, Atm; Ludwig, Rüdiger; Ashraful Kamal, Mohammad; Nahar Faruqa, Nurun; Jabeen, Sarwat

    2016-04-01

    Dhaka Metropolitan City (including Dhaka and five adjacent municipal areas) is one of the fastest developing urban regions in the world. Densely build-up areas in the developed metropolitan area of Dhaka City are subject to extensive restructuring as common six- or lower storied buildings are replaced by higher and heavier constructions. Additional stories are built on existing houses, frequently exceeding the allowable bearing pressure on the subsoil as supported by the foundations. In turn, newly developing city areas are projected in marshy terrains modified by extensive, largely unengineered landfills. In most areas, these terrains bear unfavorable building ground conditions within 30 meters. Within a collaborative technical cooperation project between Bangladesh and Germany, BGR supports GSB in the provision of geo-information for the Capital Development Authority (RAJUK). For general urban planning, RAJUK successively develops a detailed area plan (DAP) at scale 1 : 50000 for the whole Dhaka Metropolitan City area (approx. 1700 km2). Geo-information have not been considered in the present DAP. Within the project, geospatial information in form of a geomorphic map, a digital terrain model and a 3-D subsurface model covering the whole city area have been generated at a scale of 1 : 50000. An extensive engineering geological data base consisting of more than 2200 borehole data with associated Standard Penetration Testing (SPT) and lab data has been compiled. With the field testing (SPT) and engineering geological lab data, the 3-D subsurface model can be parameterized to derive important spatial subsurface information for urban planning like bearing capacity evaluations for different foundation designs or soil liquefaction potential assessments for specific earthquake scenarios. In conjunction with inundation potential evaluations for different flooding scenarios, comprehensive building ground suitability information can be derived to support risk

  10. Spatial Data Supply Chains

    NASA Astrophysics Data System (ADS)

    Varadharajulu, P.; Azeem Saqiq, M.; Yu, F.; McMeekin, D. A.; West, G.; Arnold, L.; Moncrieff, S.

    2015-06-01

    This paper describes current research into the supply of spatial data to the end user in as close to real time as possible via the World Wide Web. The Spatial Data Infrastructure paradigm has been discussed since the early 1990s. The concept has evolved significantly since then but has almost always examined data from the perspective of the supplier. It has been a supplier driven focus rather than a user driven focus. The current research being conducted is making a paradigm shift and looking at the supply of spatial data as a supply chain, similar to a manufacturing supply chain in which users play a significant part. A comprehensive consultation process took place within Australia and New Zealand incorporating a large number of stakeholders. Three research projects that have arisen from this consultation process are examining Spatial Data Supply Chains within Australia and New Zealand and are discussed within this paper.

  11. Embodied spatial cognition.

    PubMed

    Trafton, J Gregory; Harrison, Anthony M

    2011-10-01

    We present a spatial system called Specialized Egocentrically Coordinated Spaces embedded in an embodied cognitive architecture (ACT-R Embodied). We show how the spatial system works by modeling two different developmental findings: gaze-following and Level 1 perspective taking. The gaze-following model is based on an experiment by Corkum and Moore (1998), whereas the Level 1 visual perspective-taking model is based on an experiment by Moll and Tomasello (2006). The models run on an embodied robotic system.

  12. Spatial language and converseness.

    PubMed

    Burigo, Michele; Coventry, Kenny R; Cangelosi, Angelo; Lynott, Dermot

    2016-12-01

    Typical spatial language sentences consist of describing the location of an object (the located object) in relation to another object (the reference object) as in "The book is above the vase". While it has been suggested that the properties of the located object (the book) are not translated into language because they are irrelevant when exchanging location information, it has been shown that the orientation of the located object affects the production and comprehension of spatial descriptions. In line with the claim that spatial language apprehension involves inferences about relations that hold between objects it has been suggested that during spatial language apprehension people use the orientation of the located object to evaluate whether the logical property of converseness (e.g., if "the book is above the vase" is true, then also "the vase is below the book" must be true) holds across the objects' spatial relation. In three experiments using sentence acceptability rating tasks we tested this hypothesis and demonstrated that when converseness is violated people's acceptability ratings of a scene's description are reduced indicating that people do take into account geometric properties of the located object and use it to infer logical spatial relations.

  13. Acquired spatial dyslexia.

    PubMed

    Siéroff, E

    2015-08-10

    Acquired spatial dyslexia is a reading disorder frequently occurring after left or right posterior brain lesions. This article describes several types of spatial dyslexia with an attentional approach. After right posterior lesions, patients show left neglect dyslexia with errors on the left side of text, words, and non-words. The deficit is frequently associated with left unilateral spatial neglect. Severe left neglect dyslexia can be detected with unlimited exposure duration of words or non-words. Minor neglect dyslexia is detected with brief presentation of bilateral words, one in the left and one in the right visual field (phenomenon of contralesional extinction). Neglect dyslexia can be explained as a difficulty in orienting attention to the left side of verbal stimuli. With left posterior lesions, spatial dyslexia is also frequent but multiform. Right neglect dyslexia is frequent, but right unilateral spatial neglect is rare. Attentional dyslexia represents difficulty in selecting a stimulus, letter or word among other similar stimuli; it is a deficit of attentional selection, and the left hemisphere plays a crucial role in selection. Two other types of spatial dyslexia can be found after left posterior lesions: paradoxical ipsilesional extinction and stimulus-centred neglect dyslexia. Disconnections between left or right parietal attentional areas and the left temporal visual word form area could explain these deficits. Overall, a model of attention dissociating modulation, selection control, and selection positioning can help in understanding these reading disorders.

  14. Teaching Spatial Awareness to Children

    ERIC Educational Resources Information Center

    Stevens-Smith, Deborah

    2004-01-01

    An important component in the early stages of skill development is spatial awareness. This article discusses how good spatial awareness in children results from concepts that are reinforced throughout the school's curriculum. Activities for developing spatial awareness are also provided.

  15. Temporal and spatial variations in erosion rate in the Sikkim Himalaya as a function of climate and tectonics

    NASA Astrophysics Data System (ADS)

    Abrahami, R.; Van Der Beek, P.; Huyghe, P.; Carcaillet, J.

    2014-12-01

    The Tista River, a major tributary of the Brahmaputra drainage system (Eastern Himalaya -Sikkim) has recently incised its megafan at the topographic front of the mountain range by 30 meters. Neither the timing of deposition/incision of the megafan sediments, nor the erosion rates of the source areas have yet been investigated in detail. To constrain erosion rates in the hinterland at different temporal scales, we report cosmogenic nuclide (10Be) and thermochronological (apatite fission-track) data on modern river sands and map the results to evidence spatial variations of erosion/exhumation rates in Sikkim. Millennial erosion rates are significantly higher than geological exhumation rates, display stronger spatial variability and a contrasting pattern, suggesting that the processes controlling these rates are decoupled. Strong exhumation rates at geological timescales in southwest Sikkim (1.2 mm.yr-1) may be structurally controlled by uplift of the Lesser Himalayan duplex, while strong erosion rates at millennial scales in north Sikkim (5-6 mm.yr-1) suggest a climatic control. Cosmogenic nuclides were also used to date the onset of incision of the megafan. In addition, isotope geochemistry (ɛNd, 87Sr/86Sr) on modern river sands and late-Quaternary megafan sediments allows characterizing the isotopic signature of the different source areas and constraining variations in provenance of the Tista megafan deposits through time. Results show that the Tista fan deposits are mainly sourced from the High Himalayan Crystalline domain with excursions more influenced by the Lesser Himalaya domain. These results are consistent with the higher erosion rates identified in north Sikkim at millennial timescale. These data provide a new comprehensive view on modern erosion and long-term exhumation of the Sikkim Himalaya. This study will help our knowledge and understanding of erosional processes and sediment fluxes in mountainous environments as a function of climate and tectonics.

  16. Spatial ecology across scales.

    PubMed

    Hastings, Alan; Petrovskii, Sergei; Morozov, Andrew

    2011-04-23

    The international conference 'Models in population dynamics and ecology 2010: animal movement, dispersal and spatial ecology' took place at the University of Leicester, UK, on 1-3 September 2010, focusing on mathematical approaches to spatial population dynamics and emphasizing cross-scale issues. Exciting new developments in scaling up from individual level movement to descriptions of this movement at the macroscopic level highlighted the importance of mechanistic approaches, with different descriptions at the microscopic level leading to different ecological outcomes. At higher levels of organization, different macroscopic descriptions of movement also led to different properties at the ecosystem and larger scales. New developments from Levy flight descriptions to the incorporation of new methods from physics and elsewhere are revitalizing research in spatial ecology, which will both increase understanding of fundamental ecological processes and lead to tools for better management.

  17. The Spatial Standard Observer

    NASA Technical Reports Server (NTRS)

    Watson, Andrew B.; Ahumada, Albert J, Jr.

    2006-01-01

    The spatial standard observer is a computational model that provides a measure of the visibility of a target in a uniform background image or of the visual discriminability of two images. Standard observers have long been used in science and industry to quantify the discriminability of colors. Color standard observers address the spectral characteristics of visual stimuli, while the spatial standard observer (SSO), as its name indicates, addresses spatial characteristics. The SSO is based on a model of human vision. The SSO was developed in a process that included evaluation of a number of earlier mathematical models that address optical, physiological, and psychophysical aspects of spatial characteristics of human visual perception. Elements of the prior models are incorporated into the SSO, which is formulated as a compromise between accuracy and simplicity. The SSO operates on a digitized monochrome still image or on a pair of such images. The SSO consists of three submodels that operate sequentially on the input image(s): 1. A contrast model, which converts an input monochrome image to a luminance contrast image, wherein luminance values are expressed as excursions from, and normalized to, a mean; 2. A contrast-sensitivity-filter model that includes an oblique-effect filter (which accounts for the decline in contrast sensitivity at oblique viewing angles); and 3. A spatial summation model, in which responses are spatially pooled by raising each pixel to the power beta, adding the results, and raising the sum to the 1/b power. In this model, b=2.9 was found to be a suitable value. The net effect of the SSO is to compute a numerical measure of the perceptual strength of the single image, or of the visible difference (denoted the perceptual distance) between two images. The unit of a measure used in the SSO is the just noticeable difference (JND), which is a standard measure of perceptual discriminability. A target that is just visible has a measure of 1 JND.

  18. Spatial fluctuation theorem

    NASA Astrophysics Data System (ADS)

    Pérez-Espigares, Carlos; Redig, Frank; Giardinà, Cristian

    2015-08-01

    For non-equilibrium systems of interacting particles and for interacting diffusions in d-dimensions, a novel fluctuation relation is derived. The theorem establishes a quantitative relation between the probabilities of observing two current values in different spatial directions. The result is a consequence of spatial symmetries of the microscopic dynamics, generalizing in this way the Gallavotti-Cohen fluctuation theorem related to the time-reversal symmetry. This new perspective opens up the possibility of direct experimental measurements of fluctuation relations of vectorial observables.

  19. Planetary Spatial Analyst

    NASA Technical Reports Server (NTRS)

    Keely, Leslie

    2008-01-01

    This is a status report for the project entitled Planetary Spatial Analyst (PSA). This report covers activities from the project inception on October 1, 2007 to June 1, 2008. Originally a three year proposal, PSA was awarded funding for one year and required a revised work statement and budget. At the time of this writing the project is well on track both for completion of work as well as budget. The revised project focused on two objectives: build a solid connection with the target community and implement a prototype software application that provides 3D visualization and spatial analysis technologies for that community. Progress has been made for both of these objectives.

  20. Differentiating spatial light modulator

    NASA Astrophysics Data System (ADS)

    Armitage, D.

    1985-04-01

    A differentiating spatial light modulator device in which a photoreceptor and an electro-optic crystal are isolated by a dielectric mirror is discussed. The electro-optic crystal is configured to have low or zero longitudinal response, yet is sensitive to transverse electric fields. The fringe field generated by the photoreceptor (photodiode) modulates the crystal birefringence. Readout via a polarizing beamsplitter gives an output light related to the spatial gradient of the input light. In a liquid crystal embodiment of the invention, reversal of the applied voltage gives a driven off state which speeds the erasure. Storage is possible in the smectic liquid crystal phase.

  1. Heredity Factors in Spatial Visualization.

    ERIC Educational Resources Information Center

    Vandenberg, S. G.

    Spatial visualization is not yet clearly understood. Some researchers have concluded that two factors or abilities are involved, spatial orientation and spatial visualization. Different definitions and different tests have been proposed for these two abilities. Several studies indicate that women generally perform more poorly on spatial tests than…

  2. Cartography: LACIE's spatial processor

    NASA Technical Reports Server (NTRS)

    Rader, M. L.; Vela, R. R. (Principal Investigator)

    1979-01-01

    The spatial processing needs of LACIE include the location of agricultural test sites, and the registration of ground truth to LANDSAT imagery. The technological aspects of LACIE cartographic support, the need for cartography in satellite crop surveys, and proposed improvements which would enhance support of future programs are discussed.

  3. Diagonal spatial neglect

    PubMed Central

    Mark, V.; Heilman, K.

    1998-01-01

    OBJECTIVE—To determine whether stroke patients with diagonal neglect on cancellation may show diagonal neglect on line bisection, and hence to indicate whether diagonal neglect may be related solely to the type of test used or whether instead it may reflect a fundamental spatial disorder.
METHODS—Nine patients with subacute right hemispheric stroke who neglected targets primarily in the near left direction on line cancellation bisected diagonal lines of two opposing orientations: near left to far right and far left to near right. The errors were assessed to determine whether line orientation significantly affected bisection error.
RESULTS—Eight patients had significant bisection errors. One of these showed no effect of line orientation on error, consistent with lateral neglect. The remaining seven patients had a line orientation effect, indicating a net diagonal spatial bias. For the group, cancellation errors were significantly correlated with the line orientation effect on bisection errors.
CONCLUSIONS—A significant diagonal bias on two tests of spatial attention may appear in stroke patients, although the directions of the biases may differ within individual patients. None the less, diagonal neglect may be a fundamental spatial attentional disturbance of right hemispheric stroke. Greater severity of stroke deficit as indicated by cancellation error score may be associated with a greater degree of diagonal neglect on line bisection.

 PMID:9728947

  4. Handbook of Spatial Cognition

    ERIC Educational Resources Information Center

    Waller, David, Ed.; Nadel, Lynn, Ed.

    2012-01-01

    Spatial cognition is a branch of cognitive psychology that studies how people acquire and use knowledge about their environment to determine where they are, how to obtain resources, and how to find their way home. Researchers from a wide range of disciplines, including neuroscience, cognition, and sociology, have discovered a great deal about how…

  5. Study of vegetation impact on the ground surface temperature using remote sensing data with different spatial resolution

    NASA Astrophysics Data System (ADS)

    Dvornikov, Yury; Heim, Birgit; Leibman, Marina

    2013-04-01

    with the field data. The comparison involves the spatial statistics calculation. The map of the surface temperature was plotted using data from Landsat 1999 with 30 meter spatial resolution (band 6-1, High Gain). First of all, an atmospheric correction of the data was made, and then surface temperature was calculated with the algorithm (Chavez, 1988). The average temperature of the surface was calculated, except for the areas of water bodies, and then the spatial statistics was calculated within the vegetation units subdivided at the initial stage of interpretation.

  6. Particle detector spatial resolution

    DOEpatents

    Perez-Mendez, V.

    1992-12-15

    Method and apparatus for producing separated columns of scintillation layer material, for use in detection of X-rays and high energy charged particles with improved spatial resolution is disclosed. A pattern of ridges or projections is formed on one surface of a substrate layer or in a thin polyimide layer, and the scintillation layer is grown at controlled temperature and growth rate on the ridge-containing material. The scintillation material preferentially forms cylinders or columns, separated by gaps conforming to the pattern of ridges, and these columns direct most of the light produced in the scintillation layer along individual columns for subsequent detection in a photodiode layer. The gaps may be filled with a light-absorbing material to further enhance the spatial resolution of the particle detector. 12 figs.

  7. Spatially resolved multicomponent gels

    NASA Astrophysics Data System (ADS)

    Draper, Emily R.; Eden, Edward G. B.; McDonald, Tom O.; Adams, Dave J.

    2015-10-01

    Multicomponent supramolecular systems could be used to prepare exciting new functional materials, but it is often challenging to control the assembly across multiple length scales. Here we report a simple approach to forming patterned, spatially resolved multicomponent supramolecular hydrogels. A multicomponent gel is first formed from two low-molecular-weight gelators and consists of two types of fibre, each formed by only one gelator. One type of fibre in this ‘self-sorted network’ is then removed selectively by a light-triggered gel-to-sol transition. We show that the remaining network has the same mechanical properties as it would have done if it initially formed alone. The selective irradiation of sections of the gel through a mask leads to the formation of patterned multicomponent networks, in which either one or two networks can be present at a particular position with a high degree of spatial control.

  8. Spatial Phase Imaging

    NASA Technical Reports Server (NTRS)

    2006-01-01

    Frequently, scientists grow crystals by dissolving a protein in a specific liquid solution, and then allowing that solution to evaporate. The methods used next have been, variously, invasive (adding a dye that is absorbed by the protein), destructive (crushing protein/salt-crystal mixtures and observing differences between the crushing of salt and protein), or costly and time-consuming (X-ray crystallography). In contrast to these methods, a new technology for monitoring protein growth, developed in part through NASA Small Business Innovation Research (SBIR) funding from Marshall Space Flight Center, is noninvasive, nondestructive, rapid, and more cost effective than X-ray analysis. The partner for this SBIR, Photon-X, Inc., of Huntsville, Alabama, developed spatial phase imaging technology that can monitor crystal growth in real time and in an automated mode. Spatial phase imaging scans for flaws quickly and produces a 3-D structured image of a crystal, showing volumetric growth analysis for future automated growth.

  9. Spatially ordered treemaps.

    PubMed

    Wood, Jo; Dykes, Jason

    2008-01-01

    Existing treemap layout algorithms suffer to some extent from poor or inconsistent mappings between data order and visual ordering in their representation, reducing their cognitive plausibility. While attempts have been made to quantify this mismatch, and algorithms proposed to minimize inconsistency, solutions provided tend to concentrate on one-dimensional ordering. We propose extensions to the existing squarified layout algorithm that exploit the two-dimensional arrangement of treemap nodes more effectively. Our proposed spatial squarified layout algorithm provides a more consistent arrangement of nodes while maintaining low aspect ratios. It is suitable for the arrangement of data with a geographic component and can be used to create tessellated cartograms for geovisualization. Locational consistency is measured and visualized and a number of layout algorithms are compared. CIELab color space and displacement vector overlays are used to assess and emphasize the spatial layout of treemap nodes. A case study involving locations of tagged photographs in the Flickr database is described.

  10. Microchannel spatial light modulator

    NASA Technical Reports Server (NTRS)

    Warde, C.

    1981-01-01

    The Microchannel Spatial Light Modulator (MSLM), a versatile, highly sensitive, and optically addressed device being developed for real time optical information processing is discussed. The MSLM operates by converting an input optical image into a charge distribution at the surface of an electro-optic crystal. The charge distribution generates an electric field which modulates the refractive index of the crystal and thereby the phase or intensity of an image readout beam. Prototype devices employing 250 micron thick crystals exhibited a spatial resolution of 5 cycles/mm at 50% contrast, an exposure sensitivity of 2.2 nJ/cu cm and framing rates of 40 Hz with full modulation depth. The image processing operations that have been achieved using the internal processing mode of the MSLM include contrast reversal, contrast enhancement, edge enhancement, image addition and subtraction, analog and digital intensity thresholding, and binary level logic operations such as AND, OR, EXCLUSIVE OR, and NOR.

  11. Spatial Data Analysis

    NASA Astrophysics Data System (ADS)

    Haining, Robert

    2003-06-01

    Are there geographic clusters of disease cases, or hotspots of crime? Can the geography of air quality be matched to where people hospitalized for respiratory complaints actually live? Spatial data is data about the world where the attribute of interest and its location on the earth's surface are recorded. This comprehensive overview of the subject shows how the above questions can be tackled. It is written for students and researchers in geography, economics, social science, the environmental sciences and statistics.

  12. GENERATING SOPHISTICATED SPATIAL SURROGATES USING THE MIMS SPATIAL ALLOCATOR

    EPA Science Inventory

    The Multimedia Integrated Modeling System (MIMS) Spatial Allocator is open-source software for generating spatial surrogates for emissions modeling, changing the map projection of Shapefiles, and performing other types of spatial allocation that does not require the use of a comm...

  13. Detecting spatial regimes in ecosystems

    EPA Science Inventory

    Research on early warning indicators has generally focused on assessing temporal transitions with limited application of these methods to detecting spatial regimes. Traditional spatial boundary detection procedures that result in ecoregion maps are typically based on ecological ...

  14. Temporal and spatial variations in erosion rate in the Sikkim Himalaya as a function of climate and tectonics

    NASA Astrophysics Data System (ADS)

    Abrahami, Rachel; Huyghe, Pascale; van der Beek, Peter; Carcaillet, Julien

    2014-05-01

    The Tista River is a major tributary of the Brahmaputra drainage system (Eastern Himalaya). Its headwaters are located in the glaciated northernmost parts of the Sikkim and its catchment area amounts to more than 12,000 km2 including a depositional megafan (extending mostly in Bangladesh and West Bengal-India). The Tista has recently incised its megafan at the topographic front of the mountain range by about 30 meters. Neither the timing of deposition/incision of the megafan sediments, nor the erosion rates of the source areas as well as their potential relationships, have been investigated in detail. Comparing these data is essential to distinguish between a climatic and/or tectonic control of the evolution of the Sikkim Himalaya and piedmont. To constrain erosion rates in the hinterland at different temporal scales (respectively millenial and geological timescales), we report cosmogenic nuclide (10Be) and thermochronological (apatite fission-tracks) data on modern river sands. Results were mapped to evidence spatial variations of erosion/exhumation rates in the Tista catchment. Cosmogenic nuclides were also used to date the onset of incision of the megafan and relate it to potential changes in hinterland erosion. In addition, isotope geochemistry (ɛNd and 87Sr/86Sr) performed on modern river sands and Late-Quaternary megafan sediments allows characterizing the isotopic signature of the different source areas and constraining variations in provenance of the Tista megafan deposits through time in response to changing climatic conditions. Results show that the Tista fan deposits are mainly sourced from the High Himalayan Crystalline domain with excursions more influenced by the Lesser Himalaya domain. These data provide a new comprehensive view on modern erosion and long-term exhumation of the Sikkim Himalaya. This study of a "closed system" will help our knowledge and understanding of erosional processes and sediment fluxes in mountainous environments as a

  15. Spatial Data Transfer Standard (SDTS)

    USGS Publications Warehouse

    ,

    1999-01-01

    The American National Standards Institute?s (ANSI) Spatial Data Transfer Standard (SDTS) is a mechanism for archiving and transferring of spatial data (including metadata) between dissimilar computer systems. The SDTS specifies exchange constructs, such as format, structure, and content, for spatially referenced vector and raster (including gridded) data. The SDTS includes a flexible conceptual model, specifications for a quality report, transfer module specifications, data dictionary specifications, and definitions of spatial features and attributes.

  16. Contour Integration across Spatial Frequency

    ERIC Educational Resources Information Center

    Persike, Malte; Olzak, Lynn A.; Meinhardt, Gunter

    2009-01-01

    Association field models of contour integration suggest that local band-pass elements are spatially grouped to global contours within limited bands of spatial frequency (Field, Hayes, & Hess, 1993). While results for local orientation and spacing variation render support for AF models, effects of spatial frequency (SF) have rarely been addressed.…

  17. Spatial Premise Integration in Hindi

    ERIC Educational Resources Information Center

    Mishra, Ramesh Kumar

    2007-01-01

    Spatial reasoning or locating objects in a spatial space has long been an important area of research in cognitive science because analyzing space categorically and finding objects is a fundamental act of mental perception and cognition. Premise integration in tasks of spatial reasoning has recently received considerable research attention. This is…

  18. Spatial homogeneity of benthic macrofaunal biodiversity across small spatial scales.

    PubMed

    Barnes, R S K

    2016-12-01

    Spatial heterogeneity of biodiversity has been extensively researched, but its spatial homogeneity is virtually unstudied. An intertidal seagrass system at Knysna (South Africa) known to display spatially homogeneous macrobenthic species density at scales ≥0.0275 m(2) was re-investigated at four smaller spatial grains (0.0015 m(2) - 0.0095 m(2)) via a lattice of 8 × 8 stations within a 0.2 ha area. The aim was to investigate the null hypothesis that spatial homogeneity of species density is not a fixed emergent assemblage property but breaks down at small spatial grains within given spatial extents. Although assemblage abundance was significantly heterogeneous at all spatial grains investigated, both species density and functional-group density were significantly homogeneous across those same scales; observed densities not departing from those expected on the basis of independent assortment. Spatial homogeneity is therefore an emergent assemblage property within given spatial extents at Knysna and probably at equivalent sites elsewhere. Equivalent species density in South Africa, Australia and the UK at spatial grains <0.03 m(2), however, is a scale-related sampling artefact, as may be temporal homogeneity of species density at Knysna over a 3 year period, but close similarity in shape of their species occupancy distributions remains unexplained.

  19. Approximate spatial reasoning

    NASA Technical Reports Server (NTRS)

    Dutta, Soumitra

    1988-01-01

    Much of human reasoning is approximate in nature. Formal models of reasoning traditionally try to be precise and reject the fuzziness of concepts in natural use and replace them with non-fuzzy scientific explicata by a process of precisiation. As an alternate to this approach, it has been suggested that rather than regard human reasoning processes as themselves approximating to some more refined and exact logical process that can be carried out with mathematical precision, the essence and power of human reasoning is in its capability to grasp and use inexact concepts directly. This view is supported by the widespread fuzziness of simple everyday terms (e.g., near tall) and the complexity of ordinary tasks (e.g., cleaning a room). Spatial reasoning is an area where humans consistently reason approximately with demonstrably good results. Consider the case of crossing a traffic intersection. We have only an approximate idea of the locations and speeds of various obstacles (e.g., persons and vehicles), but we nevertheless manage to cross such traffic intersections without any harm. The details of our mental processes which enable us to carry out such intricate tasks in such apparently simple manner are not well understood. However, it is that we try to incorporate such approximate reasoning techniques in our computer systems. Approximate spatial reasoning is very important for intelligent mobile agents (e.g., robots), specially for those operating in uncertain or unknown or dynamic domains.

  20. Land drainage system detection using IR and visual imagery taken from autonomous mapping airship and evaluation of physical and spatial parameters of suggested method

    NASA Astrophysics Data System (ADS)

    Koska, Bronislav; Křemen, Tomáš; Štroner, Martin; Pospíšil, Jiří; Jirka, Vladimír.

    2014-10-01

    An experimental approach to the land drainage system detection and its physical and spatial parameters evaluation by the form of pilot project is presented in this paper. The novelty of the approach is partly based on using of unique unmanned aerial vehicle - airship with some specific properties. The most important parameters are carrying capacity (15 kg) and long flight time (3 hours). A special instrumentation was installed for physical characteristic testing in the locality too. The most important is 30 meter high mast with 3 meter length bracket at the top with sensors recording absolute and comparative temperature, humidity and wind speed and direction in several heights of the mast. There were also installed several measuring units recording local condition in the area. Recorded data were compared with IR images taken from airship platform. The locality is situated around village Domanín in the Czech Republic and has size about 1.8 x 1.5 km. There was build a land drainage system during the 70-ties of the last century which is made from burnt ceramic blocks placed about 70 cm below surface. The project documentation of the land drainage system exists but real state surveying haveńt been never realized. The aim of the project was land surveying of land drainage system based on infrared, visual and its combination high resolution orthophotos (10 cm for VIS and 30 cm for IR) and spatial and physical parameters evaluation of the presented procedure. The orthophoto in VIS and IR spectrum and its combination seems to be suitable for the task.

  1. Measuring the spatial accuracy of the spatial scan statistic.

    PubMed

    Read, Simon; Bath, Peter; Willett, Peter; Maheswaran, Ravi

    2011-06-01

    The spatial scan statistic is well established in spatial epidemiology. However, studies of its spatial accuracy are infrequent and vary in approach, often using multiple measures which complicate the objective ranking of different implementations of the statistic. We address this with three novel contributions. Firstly, a modular framework into which different definitions of spatial accuracy can be compared and hybridised. Secondly, we derive a new single measure, Ω, which takes account of all true and detected clusters, without the need for arbitrary weightings and irrespective of any chosen significance threshold. Thirdly, we demonstrate the new measure, alongside existing ones, in a study of the six output filter options provided by SaTScan™. The study suggests filtering overlapping detected clusters tends to reduce spatial accuracy, and visualising overlapping clusters may be better than filtering them out. Although we only address spatial accuracy, the framework and Ω may be extendible to spatio-temporal accuracy.

  2. Spatial organization of cooperation

    NASA Astrophysics Data System (ADS)

    Desprat, Nicolas

    The structure of the environment spatially confines bacteria inside groups where they live and evolve with their siblings. This population structure may not only select for individual abilities but also for group properties that would eventually enhance the fitness of the colony. In poor media, we might think that maximizing the contact with the environment would maximize the fitness of individual cells. However, we will show that the microcolony of P. aeruginosa adapts its morphogenesis to maximize cell-cell contacts rather than cell-environment interactions when iron becomes scarce in the environment. In this case, reducing the surface of exchange with the environment allows to limit the loss of secreted molecules required to efficiently fetch extracelllular iron at very low concentration.

  3. Spatial Standard Observer

    NASA Technical Reports Server (NTRS)

    Watson, Andrew B. (Inventor)

    2012-01-01

    The present invention relates to devices and methods for the measurement and/or for the specification of the perceptual intensity of a visual image, or the perceptual distance between a pair of images. Grayscale test and reference images are processed to produce test and reference luminance images. A luminance filter function is convolved with the reference luminance image to produce a local mean luminance reference image. Test and reference contrast images are produced from the local mean luminance reference image and the test and reference luminance images respectively, followed by application of a contrast sensitivity filter. The resulting images are combined according to mathematical prescriptions to produce a Just Noticeable Difference, JND value, indicative of a Spatial Standard Observer, SSO. Some embodiments include masking functions, window functions, special treatment for images lying on or near borders and pre-processing of test images.

  4. Spatial cognition and navigation

    NASA Technical Reports Server (NTRS)

    Aretz, Anthony J.

    1989-01-01

    An experiment that provides data for the development of a cognitive model of pilot flight navigation is described. The experiment characterizes navigational awareness as the mental alignment of two frames of reference: (1) the ego centered reference frame that is established by the forward view out of the cockpit and (2) the world centered reference frame that is established by the aircraft's location on a map. The data support a model involving at least two components: (1) the perceptual encoding of the navigational landmarks and (2) the mental rotation of the map's world reference frame into alignment with the ego centered reference frame. The quantitative relationships of these two factors are provided as possible inputs for a computational model of spatial cognition during flight navigation.

  5. Spatial Standard Observer

    NASA Technical Reports Server (NTRS)

    Watson, Andrw B. (Inventor)

    2010-01-01

    The present invention relates to devices and methods for the measurement and/or for the specification of the perceptual intensity of a visual image. or the perceptual distance between a pair of images. Grayscale test and reference images are processed to produce test and reference luminance images. A luminance filter function is convolved with the reference luminance image to produce a local mean luminance reference image . Test and reference contrast images are produced from the local mean luminance reference image and the test and reference luminance images respectively, followed by application of a contrast sensitivity filter. The resulting images are combined according to mathematical prescriptions to produce a Just Noticeable Difference, JND value, indicative of a Spatial Standard Observer. SSO. Some embodiments include masking functions. window functions. special treatment for images lying on or near border and pre-processing of test images.

  6. SPATIAL NEGLECT AND ATTENTION NETWORKS

    PubMed Central

    Corbetta, Maurizio; Shulman, Gordon L.

    2013-01-01

    Unilateral spatial neglect is a common neurological syndrome following predominantly right hemisphere injuries to ventral fronto-parietal cortex. We propose that neglect reflects deficits in the coding of saliency, control of spatial attention, and representation within an egocentric frame of reference, in conjunction with non-spatial deficits of reorienting, target detection, and arousal/vigilance. In contrast to theories that link spatial neglect to structural damage of specific brain regions, we argue that neglect is better explained by the physiological dysfunction of distributed cortical networks. The ventral lesions in right parietal, temporal, and frontal cortex that cause neglect directly impair non-spatial functions and hypoactivate the right hemisphere, inducing abnormalities in task-evoked activity and functional connectivity of a dorsal frontal-parietal network that controls spatial attention. The anatomy and right hemisphere dominance of neglect follows from the anatomy and laterality of the ventral regions that interact with the dorsal attention network. PMID:21692662

  7. Spatially Enabling the Health Sector

    PubMed Central

    Weeramanthri, Tarun Stephen; Woodgate, Peter

    2016-01-01

    Spatial information describes the physical location of either people or objects, and the measured relationships between them. In this article, we offer the view that greater utilization of spatial information and its related technology, as part of a broader redesign of the architecture of health information at local and national levels, could assist and speed up the process of health reform, which is taking place across the globe in richer and poorer countries alike. In making this point, we describe the impetus for health sector reform, recent developments in spatial information and analytics, and current Australasian spatial health research. We highlight examples of uptake of spatial information by the health sector, as well as missed opportunities. Our recommendations to spatially enable the health sector are applicable to high- and low-resource settings. PMID:27867933

  8. Deriving Extensional Spatial Composition Tables

    NASA Astrophysics Data System (ADS)

    El-Geresy, Baher; Abdelmoty, Alia I.; Ware, Andrew J.

    Spatial composition tables are fundamental tools for the realisation of qualitative spatial reasoning techniques. Studying the properties of these tables in relation to the spatial calculi they are based on is essential for understanding the applicability of these calculi and how they can be extended and generalised. An extensional interpretation of a spatial composition table is an important property that has been studied in the literature and is used to determine the validity of the table for the models it is proposed for. It provides means for consistency checking of ground sets of relations and for addressing spatial constraint satisfaction problems. Furthermore, two general conditions that can be used to test for extensionality of spatial composition tables are proposed and applied to the RCC8 composition table to verify the allowable models in this calculus.

  9. ALGORITHM DEVELOPMENT FOR SPATIAL OPERATORS.

    USGS Publications Warehouse

    Claire, Robert W.

    1984-01-01

    An approach is given that develops spatial operators about the basic geometric elements common to spatial data structures. In this fashion, a single set of spatial operators may be accessed by any system that reduces its operands to such basic generic representations. Algorithms based on this premise have been formulated to perform operations such as separation, overlap, and intersection. Moreover, this generic approach is well suited for algorithms that exploit concurrent properties of spatial operators. The results may provide a framework for a geometry engine to support fundamental manipulations within a geographic information system.

  10. Spatial Aspects of Interspecific Competition

    NASA Technical Reports Server (NTRS)

    Durrett, Rick; Levin, Simon

    1998-01-01

    Using several variants of a stochastic spatial model introduced by Silvertown et al., we investigate the effect of spatial distribution of individuals on the outcome of competition. First, we prove rigorously that if one species has a competitive advantage over each of the others, then eventually it takes over all the sites in the system. Second, we examine tradeoffs between competition and dispersal distance in a two-species system. Third, we consider a cyclic competitive relationship between three types. In this case, a nonspatial treatment leads to densities that follow neutrally stable cycles or even unstable spiral solutions, while a spatial model yields a stationary distribution with an interesting spatial structure.

  11. Spatial Query for Planetary Data

    NASA Technical Reports Server (NTRS)

    Shams, Khawaja S.; Crockett, Thomas M.; Powell, Mark W.; Joswig, Joseph C.; Fox, Jason M.

    2011-01-01

    Science investigators need to quickly and effectively assess past observations of specific locations on a planetary surface. This innovation involves a location-based search technology that was adapted and applied to planetary science data to support a spatial query capability for mission operations software. High-performance location-based searching requires the use of spatial data structures for database organization. Spatial data structures are designed to organize datasets based on their coordinates in a way that is optimized for location-based retrieval. The particular spatial data structure that was adapted for planetary data search is the R+ tree.

  12. One Spatial Map or Many? Spatial Coding of Connected Environments

    ERIC Educational Resources Information Center

    Han, Xue; Becker, Suzanna

    2014-01-01

    We investigated how humans encode large-scale spatial environments using a virtual taxi game. We hypothesized that if 2 connected neighborhoods are explored jointly, people will form a single integrated spatial representation of the town. However, if the neighborhoods are first learned separately and later observed to be connected, people will…

  13. Auditory Spatial Layout

    NASA Technical Reports Server (NTRS)

    Wightman, Frederic L.; Jenison, Rick

    1995-01-01

    All auditory sensory information is packaged in a pair of acoustical pressure waveforms, one at each ear. While there is obvious structure in these waveforms, that structure (temporal and spectral patterns) bears no simple relationship to the structure of the environmental objects that produced them. The properties of auditory objects and their layout in space must be derived completely from higher level processing of the peripheral input. This chapter begins with a discussion of the peculiarities of acoustical stimuli and how they are received by the human auditory system. A distinction is made between the ambient sound field and the effective stimulus to differentiate the perceptual distinctions among various simple classes of sound sources (ambient field) from the known perceptual consequences of the linear transformations of the sound wave from source to receiver (effective stimulus). Next, the definition of an auditory object is dealt with, specifically the question of how the various components of a sound stream become segregated into distinct auditory objects. The remainder of the chapter focuses on issues related to the spatial layout of auditory objects, both stationary and moving.

  14. The Space in Spatial Language

    ERIC Educational Resources Information Center

    Carlson, Laura A.; Van Deman, Shannon R.

    2004-01-01

    Projective spatial terms such as ''below'' specify the location of one object by indicating its spatial relation with respect to a reference object. These relations are defined via a reference frame that consists of a number of parameters (orientation, direction, origin, and distance) whose settings configure the space surrounding the reference…

  15. Auditory Spatial Perception without Vision

    PubMed Central

    Voss, Patrice

    2016-01-01

    Valuable insights into the role played by visual experience in shaping spatial representations can be gained by studying the effects of visual deprivation on the remaining sensory modalities. For instance, it has long been debated how spatial hearing evolves in the absence of visual input. While several anecdotal accounts tend to associate complete blindness with exceptional hearing abilities, experimental evidence supporting such claims is, however, matched by nearly equal amounts of evidence documenting spatial hearing deficits. The purpose of this review is to summarize the key findings which support either enhancements or deficits in spatial hearing observed following visual loss and to provide a conceptual framework that isolates the specific conditions under which they occur. Available evidence will be examined in terms of spatial dimensions (horizontal, vertical, and depth perception) and in terms of frames of reference (egocentric and allocentric). Evidence suggests that while early blind individuals show superior spatial hearing in the horizontal plane, they also show significant deficits in the vertical plane. Potential explanations underlying these contrasting findings will be discussed. Early blind individuals also show spatial hearing impairments when performing tasks that require the use of an allocentric frame of reference. Results obtained with late-onset blind individuals suggest that early visual experience plays a key role in the development of both spatial hearing enhancements and deficits. PMID:28066286

  16. Mechanisms for Human Spatial Competence

    NASA Astrophysics Data System (ADS)

    Gunzelmann, Glenn; Lyon, Don R.

    Research spanning decades has generated a long list of phenomena associated with human spatial information processing. Additionally, a number of theories have been proposed about the representation, organization and processing of spatial information by humans. This paper presents a broad account of human spatial competence, integrated with the ACT-R cognitive architecture. Using a cognitive architecture grounds the research in a validated theory of human cognition, enhancing the plausibility of the overall account. This work posits a close link of aspects of spatial information processing to vision and motor planning, and integrates theoretical perspectives that have been proposed over the history of research in this area. In addition, the account is supported by evidence from neuropsychological investigations of human spatial ability. The mechanisms provide a means of accounting for a broad range of phenomena described in the experimental literature.

  17. Marine spatial planning in practice

    NASA Astrophysics Data System (ADS)

    Collie, Jeremy S.; (Vic) Adamowicz, W. L.; Beck, Michael W.; Craig, Bethany; Essington, Timothy E.; Fluharty, David; Rice, Jake; Sanchirico, James N.

    2013-01-01

    Multiple competing uses of continental-shelf environments have led to a proliferation of marine spatial planning initiatives, together with expert guidance on marine spatial planning. This study provides an empirical review of marine spatial plans, their attributes, and the extent to which the expert guidance is actually being followed. We performed a structured review of 16 existing marine spatial plans and created an idealized marine spatial plan from the steps included in recent expert papers. A cluster analysis of the yes/no answers to 28 questions was used to ordinate the 16 marine spatial plans and to compare them with the idealized plan. All the plans that have been implemented have a high-level government mandate and the authority to implement spatial planning vested in existing institutions. Almost all the plans used data with clear criteria for data inclusion. Stakeholders were included in almost all the plans; they did not participate in all stages of the planning process but their roles were generally clearly defined. Decision-support tools were applied inconsistently across plans and were seldom used dynamically over time. Most spatial planning processes did not select specific outcomes, such as preferred use scenarios. Success is defined inconsistently across plans; in half the cases there are no metrics of success with reference benchmarks. Although monitoring is included in the majority of plans, only in some cases do monitoring results feed back into management decisions. The process of marine spatial planning had advanced in that some of the more recent plans were developed more quickly and contain more desirable attributes than earlier plans. Even so, existing marine spatial plans are heterogeneous—there are essential ingredients, but no single recipe for success.

  18. Spatial-temporal data mining

    NASA Astrophysics Data System (ADS)

    Pokrajac, Dragoljub Milos

    Spatial-temporal data mining techniques have become increasingly important in emerging fields such as remote sensing, precision agriculture, geoscience and brain imaging. In this Thesis, novel spatial-temporal data mining methods and algorithms are presented. After the introductory remarks, modeling spatial-temporal attributes with short observation history using spatial-temporal autoregressive models on uniform grid is explored. Model specifications (including covariance structure and stationarity) are discussed as well as issues in model identification, estimation and forecasting on three different sampling schedules. The proposed technique is experimentally evaluated on simulated spatial-temporal processes that confirm to model assumptions as well as on real-life agricultural data. Subsequently, we proceed with spatial-temporal prediction of a response variable with a partial observability of influential attributes. After mathematical definition of the proposed model, evaluation of the estimation technique on synthetic data that conform to the modeling assumptions is performed and a model is assessed on simulated realistic spatial-temporal data, obtained using the proposed data generator. The following part of the Thesis is dedicated to spatial-temporal profit optimization using neural network modeling. Profit optimization is proposed using a two-phase process that consists of estimation of response/attribute dependence and profit optimization for a particular tuple of attribute values. The proposed method is evaluated on simulated precision agriculture data. Next, we introduce a spatial-temporal data simulator, which is an important tool for evaluation of knowledge discovery methods for spatial-temporal domains. Various aspects of the proposed data generator are discussed, including generation of features and simulation of response variable as well as a practical implementation of the proposed method and its application on experiments with simulated data. The

  19. Six Myths About Spatial Thinking

    NASA Astrophysics Data System (ADS)

    Newcombe, Nora S.; Stieff, Mike

    2012-04-01

    Visualizations are an increasingly important part of scientific education and discovery. However, users often do not gain knowledge from them in a complete or efficient way. This article aims to direct research on visualizations in science education in productive directions by reviewing the evidence for widespread assumptions that learning styles, sex differences, developmental stages, and spatial language determine the impact of visualizations on science learning. First, we examine the assumption that people differ in their verbal versus visual learning style. Due to the lack of rigorous evaluation, there is no current support for this distinction. Future research should distinguish between two different kinds of visual learning style. Second, we consider the belief that there are large and intractable sex differences in spatial ability resultant from immutable biological reasons. Although there are some spatial sex differences (in some types of spatial tests although not all), there is actually only very mixed support for biological causation. Most important, there is conclusive evidence that spatial skills can be improved through training and education. Third, we explore educators' use of Piaget's ideas about spatial development to draw conclusions about 'developmental appropriateness'. However, recent research on spatial development has focused on identifying sequences that begin with early starting points of skill, and spatial education is possible in some form at all ages. Fourth, although spatial language does not determine spatial thought, it does frame attention in a way that can have impact on learning and understanding. We examine the empirical support for each assumption and its relevance to future research on visualizations in science education.

  20. Predicting cognitive styles from spatial abilities.

    PubMed

    Nori, Raffaella; Giusberti, Fiorella

    2006-01-01

    Previous studies on spatial memory reveal that people represent spatial information in 3 different forms: landmark, route, and survey. The aim of this work was to assess spatial abilities in order to predict a person's cognitive style. In order to do this we used 9 different spatial tasks, which were linked with these 3 forms of spatial representations. We found that the 9 spatial tasks are able to distinguish different levels of spatial ability.

  1. The emergence of spatial cyberinfrastructure

    PubMed Central

    Wright, Dawn J.; Wang, Shaowen

    2011-01-01

    Cyberinfrastructure integrates advanced computer, information, and communication technologies to empower computation-based and data-driven scientific practice and improve the synthesis and analysis of scientific data in a collaborative and shared fashion. As such, it now represents a paradigm shift in scientific research that has facilitated easy access to computational utilities and streamlined collaboration across distance and disciplines, thereby enabling scientific breakthroughs to be reached more quickly and efficiently. Spatial cyberinfrastructure seeks to resolve longstanding complex problems of handling and analyzing massive and heterogeneous spatial datasets as well as the necessity and benefits of sharing spatial data flexibly and securely. This article provides an overview and potential future directions of spatial cyberinfrastructure. The remaining four articles of the special feature are introduced and situated in the context of providing empirical examples of how spatial cyberinfrastructure is extending and enhancing scientific practice for improved synthesis and analysis of both physical and social science data. The primary focus of the articles is spatial analyses using distributed and high-performance computing, sensor networks, and other advanced information technology capabilities to transform massive spatial datasets into insights and knowledge. PMID:21467227

  2. The emergence of spatial cyberinfrastructure.

    PubMed

    Wright, Dawn J; Wang, Shaowen

    2011-04-05

    Cyberinfrastructure integrates advanced computer, information, and communication technologies to empower computation-based and data-driven scientific practice and improve the synthesis and analysis of scientific data in a collaborative and shared fashion. As such, it now represents a paradigm shift in scientific research that has facilitated easy access to computational utilities and streamlined collaboration across distance and disciplines, thereby enabling scientific breakthroughs to be reached more quickly and efficiently. Spatial cyberinfrastructure seeks to resolve longstanding complex problems of handling and analyzing massive and heterogeneous spatial datasets as well as the necessity and benefits of sharing spatial data flexibly and securely. This article provides an overview and potential future directions of spatial cyberinfrastructure. The remaining four articles of the special feature are introduced and situated in the context of providing empirical examples of how spatial cyberinfrastructure is extending and enhancing scientific practice for improved synthesis and analysis of both physical and social science data. The primary focus of the articles is spatial analyses using distributed and high-performance computing, sensor networks, and other advanced information technology capabilities to transform massive spatial datasets into insights and knowledge.

  3. Spatial memory in foraging games.

    PubMed

    Kerster, Bryan E; Rhodes, Theo; Kello, Christopher T

    2016-03-01

    Foraging and foraging-like processes are found in spatial navigation, memory, visual search, and many other search functions in human cognition and behavior. Foraging is commonly theorized using either random or correlated movements based on Lévy walks, or a series of decisions to remain or leave proximal areas known as "patches". Neither class of model makes use of spatial memory, but search performance may be enhanced when information about searched and unsearched locations is encoded. A video game was developed to test the role of human spatial memory in a canonical foraging task. Analyses of search trajectories from over 2000 human players yielded evidence that foraging movements were inherently clustered, and that clustering was facilitated by spatial memory cues and influenced by memory for spatial locations of targets found. A simple foraging model is presented in which spatial memory is used to integrate aspects of Lévy-based and patch-based foraging theories to perform a kind of area-restricted search, and thereby enhance performance as search unfolds. Using only two free parameters, the model accounts for a variety of findings that individually support competing theories, but together they argue for the integration of spatial memory into theories of foraging.

  4. Routing Algorithm Exploits Spatial Relations

    NASA Technical Reports Server (NTRS)

    Okino, Clayton; Jennings, Esther

    2004-01-01

    A recently developed routing algorithm for broadcasting in an ad hoc wireless communication network takes account of, and exploits, the spatial relationships among the locations of nodes, in addition to transmission power levels and distances between the nodes. In contrast, most prior algorithms for discovering routes through ad hoc networks rely heavily on transmission power levels and utilize limited graph-topology techniques that do not involve consideration of the aforesaid spatial relationships. The present algorithm extracts the relevant spatial-relationship information by use of a construct denoted the relative-neighborhood graph (RNG).

  5. Spatial Data Management System (SDMS)

    NASA Technical Reports Server (NTRS)

    Hutchison, Mark W.

    1994-01-01

    The Spatial Data Management System (SDMS) is a testbed for retrieval and display of spatially related material. SDMS permits the linkage of large graphical display objects with detail displays and explanations of its smaller components. SDMS combines UNIX workstations, MIT's X Window system, TCP/IP and WAIS information retrieval technology to prototype a means of associating aggregate data linked via spatial orientation. SDMS capitalizes upon and extends previous accomplishments of the Software Technology Branch in the area of Virtual Reality and Automated Library Systems.

  6. Spatial features register: toward standardization of spatial features

    USGS Publications Warehouse

    Cascio, Janette

    1994-01-01

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

  7. Spatial distribution and seasonal variability of chlorophyll-a concentration in the Azov Sea turbid waters by means of remote sensing and continuous fluorescence measurements

    NASA Astrophysics Data System (ADS)

    Saprygin, V. V.

    2011-12-01

    The goal of this study was to apply continuous fluorometric and remote estimation of chlorophyll-a concentration (Cchl) techniques to complex turbid waters of Azov Sea and explore Cchl temporal variation and spatial pattern. Azov Sea is the shallowest sea in the world with maximum depth below 15 m. Its maximum salinity is about 14%; total suspended solids and chlorophyll-a concentrations reach 120 [tex]g m^{-3}[/tex] and 100 [tex]mg m^{-3}[/tex] respectively in Taganrog Bay, daily production varies up to 3.5 [tex]gC_{org} m^{-3}[/tex]. Chlorophyll-a concentrations were measured in 2008-2010 year-round spectrophotometrically, 446 water samples were taken to calibrate fluorometerical and remote sensing data. The highest recorded concentration was 149.3, the lowest - 0.3 [tex]mg m^{-3}[/tex]. Continuous-flow fluorometer was applied in the course of 3 expeditions to Taganrog Bay to measure chlorophyll-a fluorescence (Fchl) each 30 meters along the ship path. Two-cuvette fluorometer was used to discount the influence of dissolved organic matter. Fchl measurements were calibrated and Cchl profiles derieved to estimate Cchl spatial heterogeneity in close scale. Fchl measurements were also made during moorings each 6 seconds to estimate temporal Cchl variability. Recently published algorithm based on reflectance in the red and the near-infrared (NIR) spectral regions was applied to MERIS data for the remote estimation of Cchl. Taking in account fluorometric Cchl spatial heterogeneity estimation, the algorithm for culling the outliers in Cchl fields derived from satellite data was developed. 74 images were processed to Cchl maps and then averaged monthly. Consequently, Cchl spatial distribution and seasonal variability were studied. Spectrophotometric, flourumetric measurements and values obtained by NIR-red algorithm showed strong correlation in turbid Case II waters of Azov Sea. Fluorometric and remote measurements showed high Cchl variations in short and long terms

  8. Spatial data discretization methods for geocomputation

    NASA Astrophysics Data System (ADS)

    Cao, Feng; Ge, Yong; Wang, Jinfeng

    2014-02-01

    Geocomputation provides solutions to complex geographic problems. Continuous and discrete spatial data are involved in the geocomputational process; however, geocomputational methods for discrete spatial data cannot be directly applied to continuous or mixed spatial data. Therefore, discretization methods for continuous or mixed spatial data are involved in the process. Since spatial data has spatial features, such as association, heterogeneity and spatial structure, these features cannot be handled by traditional discretization methods. Therefore, this work develops feature-based spatial data discretization methods that achieve optimal discretization results for spatial data using spatial information implicit in those features. Two discretization methods considering the features of spatial data are presented. One is an unsupervised method considering autocorrelation of spatial data and the other is a supervised method considering spatial heterogeneity. Discretization processes of the two methods are exemplified using neural tube defects (NTD) for Heshun County in Shanxi Province, China. Effectiveness is also assessed.

  9. The Detection of Clusters with Spatial Heterogeneity

    ERIC Educational Resources Information Center

    Zhang, Zuoyi

    2011-01-01

    This thesis consists of two parts. In Chapter 2, we focus on the spatial scan statistics with overdispersion and Chapter 3 is devoted to the randomized permutation test for identifying local patterns of spatial association. The spatial scan statistic has been widely used in spatial disease surveillance and spatial cluster detection. To apply it, a…

  10. Spatial degradation of satellite data

    NASA Technical Reports Server (NTRS)

    Justice, C. O.; Markham, B. L.; Townshend, J. R. G.; Kennard, R. L.

    1989-01-01

    Consideration is given to a technique for spatially degrading high-resolution satellite data to produce comparable data sets over a range of coarser resolutions. Landsat MSS data is used to produce seven spatial resolution data sets by applying a spatial filter designed to simulate sensor response. Also, spatial degradation of coarse resolution data to provide data compression for the production of global-scale data sets is examined. NOAA AVHRR Global Area Coverage data is compared to other sampling procedures. It is found that sampling procedures that incorporate averaging result in decreased variance, while sampling procedures adopting single-value selection have higher variances and produce data values comparable with those from the original data.

  11. Spatial equation for water waves

    NASA Astrophysics Data System (ADS)

    Dyachenko, A. I.; Zakharov, V. E.

    2016-02-01

    A compact spatial Hamiltonian equation for gravity waves on deep water has been derived. The equation is dynamical and can describe extreme waves. The equation for the envelope of a wave train has also been obtained.

  12. Thermodynamic Model of Spatial Memory

    NASA Astrophysics Data System (ADS)

    Kaufman, Miron; Allen, P.

    1998-03-01

    We develop and test a thermodynamic model of spatial memory. Our model is an application of statistical thermodynamics to cognitive science. It is related to applications of the statistical mechanics framework in parallel distributed processes research. Our macroscopic model allows us to evaluate an entropy associated with spatial memory tasks. We find that older adults exhibit higher levels of entropy than younger adults. Thurstone's Law of Categorical Judgment, according to which the discriminal processes along the psychological continuum produced by presentations of a single stimulus are normally distributed, is explained by using a Hooke spring model of spatial memory. We have also analyzed a nonlinear modification of the ideal spring model of spatial memory. This work is supported by NIH/NIA grant AG09282-06.

  13. 40 CFR 201.24 - Procedures for measurement at a 30 meter (100 feet) distance of the noise from locomotive and...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... meter (100 feet) distance of the noise from locomotive and rail car operations and locomotive load cell... locomotive and rail car operations and locomotive load cell test stands. (a) Microphone positions. (1) The... measured. (b) Stationary locomotive and locomotive load cell test stand tests. (1) For...

  14. 40 CFR 201.24 - Procedures for measurement at a 30 meter (100 feet) distance of the noise from locomotive and...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... meter (100 feet) distance of the noise from locomotive and rail car operations and locomotive load cell... locomotive and rail car operations and locomotive load cell test stands. (a) Microphone positions. (1) The... measured. (b) Stationary locomotive and locomotive load cell test stand tests. (1) For...

  15. 40 CFR 201.24 - Procedures for measurement at a 30 meter (100 feet) distance of the noise from locomotive and...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... meter (100 feet) distance of the noise from locomotive and rail car operations and locomotive load cell... locomotive and rail car operations and locomotive load cell test stands. (a) Microphone positions. (1) The... measured. (b) Stationary locomotive and locomotive load cell test stand tests. (1) For...

  16. Design and initial testing of a one-bladed 30-meter-diameter rotor on the NASA/DOE mod-O wind turbine

    NASA Technical Reports Server (NTRS)

    Corrigan, R. D.; Ensworth, C. B. F.

    1986-01-01

    The concept of a one-bladed horizontal-axis wind turbine has been of interest to wind turbine designers for many years. Many designs and economic analyses of one-bladed wind turbines have been undertaken by both United States and European wind energy groups. The analyses indicate significant economic advantages but at the same time, significant dynamic response concerns. In an effort to develop a broad data base on wind turbine design and operations, the NASA Wind Energy Project Office has tested a one-bladed rotor at the NASA/DOE Mod-O Wind Turbine Facility. This is the only known test on an intermediate-sized one-bladed rotor in the United States. The 15.2-meter-radius rotor consists of a tip-controlled blade and a counterweight assembly. A rigorous test series was conducted in the Fall of 1985 to collect data on rotor performance, drive train/generator dynamics, structural dynamics, and structural loads. This report includes background information on one-bladed rotor concepts, and Mod-O one-bladed rotor test configuration, supporting design analysis, the Mod-O one-blade rotor test plan, and preliminary test results.

  17. Doppler recordings after diving to depth of 30 meters at high altitude of 4,919 meters (16,138 feet) during the Tilicho Lake Expedition 2007.

    PubMed

    Kot, J; Sicko, Z; Zyszkowski, M; Brajta, M

    2014-01-01

    When going to high altitude (higher than 2,400 meters above mean sea level [about 8,200 feet]), human physiology is strongly affected by changes in atmospheric conditions, including decreased ambient pressure and hypobaric hypoxia, which can lead to severe hypoxemia, brain and/or pulmonary edema, negative changes in body and blood composition, as well as disturbances in regional microcirculation. When adding other factors, such as dehydration, physical exercise and exposure to low temperature, it is likely that nitrogen desaturation after diving at such environmental conditions is far from optimal, There are only single reports on diving at high alti-tudes. In 2007 a Polish team of climbers and divers participated in the Tilicho Lake and Peak Expedition to the Himalaya Mountains in Nepal. During this expedition, four divers conducted six dives in the Tilicho Lake at altitude of 4,919 meters above mean sea level equivalent (16,138 feet) to a maximum depth of 15 meters of fresh water (mfw) (equivalent to 28 mfw at sea level by the Cross Correction method) and 30 mfw (equivalent to 57 mfw at sea level "by Cross correction). Decompression debt was calculated using Cross Correction with some additional safety add-ons. Precordial Doppler recordings were taken every 15 minutes until 90 minutes after surfacing. No signs or symptoms of decompression sickness were observed after diving but in one diver, very high bubble grade Doppler signals were recorded. It can be concluded that diving at high altitude should be accompanied by additional safety precautions as well as taking into account personal sensitivity for such conditions.

  18. A comparison of levels of bat flight and foraging activity at 10 meters and 30 meters above drained Carolina bays and reference bays, prior to bay restoration.

    SciTech Connect

    Menzel, Michael, A.; Ford, W., Mark; Edwards, John, W.; Kilgo, John, C.

    2001-08-01

    A technical report of a monitoring study of bat flight and foraging activity above drained and undrained Carolina bays at the Savannah River Site (SRS), located near Aiken, South Carolina. In order to determine if the vegetational community type or structure of the forest community surrounding the bays affected bat activity levels, bat activity was monitored over 3 drained and 3 undrained reference bays surrounded by pine/mixed hardwood communities and 3 drained and 3 undrained reference bays surrounded by pine monocultures. Bat activity was monitored using time expansion bat detectors. Calls were recorded to Sony Professional tape recorders (Sony WMD3). Detectors positioned at 10 m heights were linked directly to the tape recorders. Time expansion radiomicrophones were used to monitor activity at 30 m heights. The radiomicrophones were attached to 2-m diameter helium balloons and suspended approximately 30 m above the forest floor. Calls detected by the radiomicrophones were transmitted via a FM narrowband frequency to a scanner on the ground.

  19. 40 CFR 201.24 - Procedures for measurement at a 30 meter (100 feet) distance of the noise from locomotive and...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... meter (100 feet) distance of the noise from locomotive and rail car operations and locomotive load cell... locomotive and rail car operations and locomotive load cell test stands. (a) Microphone positions. (1) The... measured. (b) Stationary locomotive and locomotive load cell test stand tests. (1) For...

  20. 40 CFR 201.24 - Procedures for measurement at a 30 meter (100 feet) distance of the noise from locomotive and...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... meter (100 feet) distance of the noise from locomotive and rail car operations and locomotive load cell... locomotive and rail car operations and locomotive load cell test stands. (a) Microphone positions. (1) The... measured. (b) Stationary locomotive and locomotive load cell test stand tests. (1) For...

  1. Testing of a one-bladed 30-meter-diameter rotor on the DOE/NASA Mod-O wind turbine

    NASA Technical Reports Server (NTRS)

    Ensworth, C. B. F., III; Corrigan, R. D.; Berkowitz, B. M.

    1988-01-01

    Tests were conducted on the DOE/NASA Mod-O 200-kW horizontal-axis wind turbine in a one-bladed rotor configuration. The objectives of the test were to evaluate the performance, loads, and dynamic characteristics of a one-bladed rotor, and then to compare these parameters with those of an aerodynamically similar two-bladed rotor configuration. Test operations showed that this intermediate-size (15.2-m radius) one-bladed rotor configuration can be operated successfully. Test results show that the one-bladed rotor had cyclic blade loads comparable to those of a two-bladed rotor. A moderate power penalty equivalent to a reduction in windspeed of 1 m/sec occurred with the one-bladed rotor when operated at a rotor speed 50 percent higher than that of the two-bladed rotor.

  2. Dealing with spatial heterogeneity

    NASA Astrophysics Data System (ADS)

    Marsily, Gh.; Delay, F.; Gonçalvès, J.; Renard, Ph.; Teles, V.; Violette, S.

    2005-03-01

    Heterogeneity can be dealt with by defining homogeneous equivalent properties, known as averaging, or by trying to describe the spatial variability of the rock properties from geologic observations and local measurements. The techniques available for these descriptions are mostly continuous Geostatistical models, or discontinuous facies models such as the Boolean, Indicator or Gaussian-Threshold models and the Markov chain model. These facies models are better suited to treating issues of rock strata connectivity, e.g. buried high permeability channels or low permeability barriers, which greatly affect flow and, above all, transport in aquifers. Genetic models provide new ways to incorporate more geology into the facies description, an approach that has been well developed in the oil industry, but not enough in hydrogeology. The conclusion is that future work should be focused on improving the facies models, comparing them, and designing new in situ testing procedures (including geophysics) that would help identify the facies geometry and properties. A world-wide catalog of aquifer facies geometry and properties, which could combine site genesis and description with methods used to assess the system, would be of great value for practical applications. On peut aborder le problème de l'hétérogénéité en s'efforçant de définir une perméabilité équivalente homogène, par prise de moyenne, ou au contraire en décrivant la variation dans l'espace des propriétés des roches à partir des observations géologiques et des mesures locales. Les techniques disponibles pour une telle description sont soit continues, comme l'approche Géostatistique, soit discontinues, comme les modèles de faciès, Booléens, ou bien par Indicatrices ou Gaussiennes Seuillées, ou enfin Markoviens. Ces modèles de faciès sont mieux capables de prendre en compte la connectivité des strates géologiques, telles que les chenaux enfouis à forte perméabilité, ou au contraire les faci

  3. Spatial Statistical Data Fusion (SSDF)

    NASA Technical Reports Server (NTRS)

    Braverman, Amy J.; Nguyen, Hai M.; Cressie, Noel

    2013-01-01

    As remote sensing for scientific purposes has transitioned from an experimental technology to an operational one, the selection of instruments has become more coordinated, so that the scientific community can exploit complementary measurements. However, tech nological and scientific heterogeneity across devices means that the statistical characteristics of the data they collect are different. The challenge addressed here is how to combine heterogeneous remote sensing data sets in a way that yields optimal statistical estimates of the underlying geophysical field, and provides rigorous uncertainty measures for those estimates. Different remote sensing data sets may have different spatial resolutions, different measurement error biases and variances, and other disparate characteristics. A state-of-the-art spatial statistical model was used to relate the true, but not directly observed, geophysical field to noisy, spatial aggregates observed by remote sensing instruments. The spatial covariances of the true field and the covariances of the true field with the observations were modeled. The observations are spatial averages of the true field values, over pixels, with different measurement noise superimposed. A kriging framework is used to infer optimal (minimum mean squared error and unbiased) estimates of the true field at point locations from pixel-level, noisy observations. A key feature of the spatial statistical model is the spatial mixed effects model that underlies it. The approach models the spatial covariance function of the underlying field using linear combinations of basis functions of fixed size. Approaches based on kriging require the inversion of very large spatial covariance matrices, and this is usually done by making simplifying assumptions about spatial covariance structure that simply do not hold for geophysical variables. In contrast, this method does not require these assumptions, and is also computationally much faster. This method is

  4. Spatial mental representations derived from spatial descriptions: the predicting and mediating roles of spatial preferences, strategies, and abilities.

    PubMed

    Meneghetti, Chiara; Ronconi, Lucia; Pazzaglia, Francesca; De Beni, Rossana

    2014-08-01

    The aim of this research was to investigate how spatial self-assessments and spatial cognitive abilities jointly influence the construction of mental representations derived from spatial descriptions. Two studies were conducted using the path models approach to test to what extent spatial self-assessments (Study 1, 194 participants) and the combination of the latter with spatial abilities (Study 2, 206 participants) can be modelled to predict memory for spatial descriptions. In both studies, we recorded spatial representation preferences (distinguishing between survey, route, and landmark-focused mode) and self-reported strategies used to memorize descriptions (distinguishing between survey, route, and verbal strategies); in Study 2, we also measured spatial abilities by testing mental rotation (MR) and visuo-spatial working memory (VSWM). Participants listened to spatial descriptions and then completed recall tasks. In both studies, the final path models showed that spatial preferences influenced spatial recall through the mediation of congruent strategies: that is a survey (route) preference influenced spatial recall mediated by a survey (route) strategy. MR predicted spatial recall, mediated by both VSWM and survey strategy (Study 2). Overall, these findings indicate that spatial preferences (particularly for a survey mode) in association with spatial abilities effectively concur to help form mental representations derived from spatial descriptions.

  5. Spatial and Spatiotemporal Data Mining: Recent Advances

    SciTech Connect

    Shekhar, Shashi; Vatsavai, Raju; Celik, Mete

    2008-01-01

    Explosive growth in geospatial data and the emergence of new spatial technologies emphasize the need for automated discovery of spatial knowledge. Spatial data mining is the process of discovering interesting and previously unknown, but potentially useful patterns from large spatial databases. The complexity of spatial data and intrinsic spatial relationships limits the usefulness of conventional data mining techniques for extracting spatial patterns. In this chapter we explore the emerging field of spatial data mining, focusing on four major topics: prediction and classification, outlier detection, co-location mining, and clustering. Spatiotemporal data mining is also briefly discussed.

  6. SPATIAL MISMATCH OR RACIAL MISMATCH?*

    PubMed Central

    Hellerstein, Judith K.; Neumark, David; McInerney, Melissa

    2008-01-01

    We contrast the spatial mismatch hypothesis with what we term the racial mismatch hypothesis – that the problem is not a lack of jobs, per se, where blacks live, but a lack of jobs where blacks live into which blacks are hired. We first report new evidence on the spatial mismatch hypothesis, using data from Census Long-Form respondents. We construct direct measures of the presence of jobs in detailed geographic areas, and find that these job density measures are related to employment of black male residents in ways that would be predicted by the spatial mismatch hypothesis – in particular that spatial mismatch is primarily an issue for low-skilled black male workers. We then look at mismatch along not only spatial lines but racial lines as well, by estimating the effects of job density measures that are disaggregated by race. We find that it is primarily black job density that influences black male employment, whereas white job density has little if any influence on their employment. The evidence implies that space alone plays a relatively minor role in low black male employment rates. PMID:19727422

  7. Spatial filtering with photonic crystals

    SciTech Connect

    Maigyte, Lina; Staliunas, Kestutis

    2015-03-15

    Photonic crystals are well known for their celebrated photonic band-gaps—the forbidden frequency ranges, for which the light waves cannot propagate through the structure. The frequency (or chromatic) band-gaps of photonic crystals can be utilized for frequency filtering. In analogy to the chromatic band-gaps and the frequency filtering, the angular band-gaps and the angular (spatial) filtering are also possible in photonic crystals. In this article, we review the recent advances of the spatial filtering using the photonic crystals in different propagation regimes and for different geometries. We review the most evident configuration of filtering in Bragg regime (with the back-reflection—i.e., in the configuration with band-gaps) as well as in Laue regime (with forward deflection—i.e., in the configuration without band-gaps). We explore the spatial filtering in crystals with different symmetries, including axisymmetric crystals; we discuss the role of chirping, i.e., the dependence of the longitudinal period along the structure. We also review the experimental techniques to fabricate the photonic crystals and numerical techniques to explore the spatial filtering. Finally, we discuss several implementations of such filters for intracavity spatial filtering.

  8. Spatial Vision in Bombus terrestris

    PubMed Central

    Chakravarthi, Aravin; Baird, Emily; Dacke, Marie; Kelber, Almut

    2016-01-01

    Bombus terrestris is one of the most commonly used insect models to investigate visually guided behavior and spatial vision in particular. Two fundamental measures of spatial vision are spatial resolution and contrast sensitivity. In this study, we report the threshold of spatial resolution in B. terrestris and characterize the contrast sensitivity function of the bumblebee visual system for a dual choice discrimination task. We trained bumblebees in a Y-maze experimental set-up to associate a vertical sinusoidal grating with a sucrose reward, and a horizontal grating with absence of a reward. Using a logistic psychometric function, we estimated a resolution threshold of 0.21 cycles deg−1 of visual angle. This resolution is in the same range but slightly lower than that found in honeybees (Apis mellifera and A. cerana) and another bumblebee species (B. impatiens). We also found that the contrast sensitivity of B. terrestris was 1.57 for the spatial frequency 0.090 cycles deg−1 and 1.26 for 0.18 cycles deg−1. PMID:26912998

  9. Detecting spatial regimes in ecosystems

    USGS Publications Warehouse

    Sundstrom, Shana M.; Eason, Tarsha; Nelson, R. John; Angeler, David G.; Barichievy, Chris; Garmestani, Ahjond S.; Graham, Nicholas A.J.; Granholm, Dean; Gunderson, Lance; Knutson, Melinda; Nash, Kirsty L.; Spanbauer, Trisha; Stow, Craig A.; Allen, Craig R.

    2017-01-01

    Research on early warning indicators has generally focused on assessing temporal transitions with limited application of these methods to detecting spatial regimes. Traditional spatial boundary detection procedures that result in ecoregion maps are typically based on ecological potential (i.e. potential vegetation), and often fail to account for ongoing changes due to stressors such as land use change and climate change and their effects on plant and animal communities. We use Fisher information, an information theory-based method, on both terrestrial and aquatic animal data (U.S. Breeding Bird Survey and marine zooplankton) to identify ecological boundaries, and compare our results to traditional early warning indicators, conventional ecoregion maps and multivariate analyses such as nMDS and cluster analysis. We successfully detected spatial regimes and transitions in both terrestrial and aquatic systems using Fisher information. Furthermore, Fisher information provided explicit spatial information about community change that is absent from other multivariate approaches. Our results suggest that defining spatial regimes based on animal communities may better reflect ecological reality than do traditional ecoregion maps, especially in our current era of rapid and unpredictable ecological change.

  10. Spatialization of Time in Mian

    PubMed Central

    Fedden, Sebastian; Boroditsky, Lera

    2012-01-01

    We examine representations of time among the Mianmin of Papua New Guinea. We begin by describing the patterns of spatial and temporal reference in Mian. Mian uses a system of spatial terms that derive from the orientation and direction of the Hak and Sek rivers and the surrounding landscape. We then report results from a temporal arrangement task administered to a group of Mian speakers. The results reveal evidence for a variety of temporal representations. Some participants arranged time with respect to their bodies (left to right or toward the body). Others arranged time as laid out on the landscape, roughly along the east/west axis (either east to west or west to east). This absolute pattern is consistent both with the axis of the motion of the sun and the orientation of the two rivers, which provides the basis for spatial reference in the Mian language. The results also suggest an increase in left to right temporal representations with increasing years of formal education (and the reverse pattern for absolute spatial representations for time). These results extend previous work on spatial representations for time to a new geographical region, physical environment, and linguistic and cultural system. PMID:23181037

  11. Spatial aggregation: Language and applications

    SciTech Connect

    Bailey-Kellogg, C.; Zhao, F.; Yip, K.

    1996-12-31

    Spatial aggregation is a framework for organizing computations around image-like, analogue representations of physical processes in data interpretation and control tasks. It conceptualizes common computational structures in a class of implemented problem solvers for difficult scientific and engineering problems. It comprises a mechanism, a language, and a programming style. The spatial aggregation mechanism transforms a numerical input field to successively higher-level descriptions by applying a small, identical set of operators to each layer given a metric, neighborhood relation and equivalence relation. This paper describes the spatial aggregation language and its applications. The spatial aggregation language provides two abstract data types - neighborhood graph and field - and a set of interface operators for constructing the transformations of the field, together with a library of component implementations from which a user can mix-and-match and specialize for a particular application. The language allows users to isolate and express important computational ideas in different problem domains while hiding low-level details. We illustrate the use of the language with examples ranging from trajectory grouping in dynamics interpretation to region growing in image analysis. Programs for these different task domains can be written in a modular, concise fashion in the spatial aggregation language.

  12. Spatial uncertainty and ecological models

    SciTech Connect

    Jager, Yetta; King, Anthony Wayne

    2004-07-01

    Applied ecological models that are used to understand and manage natural systems often rely on spatial data as input. Spatial uncertainty in these data can propagate into model predictions. Uncertainty analysis, sensitivity analysis, error analysis, error budget analysis, spatial decision analysis, and hypothesis testing using neutral models are all techniques designed to explore the relationship between variation in model inputs and variation in model predictions. Although similar methods can be used to answer them, these approaches address different questions. These approaches differ in (a) whether the focus is forward or backward (forward to evaluate the magnitude of variation in model predictions propagated or backward to rank input parameters by their influence); (b) whether the question involves model robustness to large variations in spatial pattern or to small deviations from a reference map; and (c) whether processes that generate input uncertainty (for example, cartographic error) are of interest. In this commentary, we propose a taxonomy of approaches, all of which clarify the relationship between spatial uncertainty and the predictions of ecological models. We describe existing techniques and indicate a few areas where research is needed.

  13. Spatial memory: are lizards really deficient?

    PubMed

    Ladage, L D; Roth, T C; Cerjanic, A M; Sinervo, B; Pravosudov, V V

    2012-12-23

    In many animals, behaviours such as territoriality, mate guarding, navigation and food acquisition rely heavily on spatial memory abilities; this has been demonstrated in diverse taxa, from invertebrates to mammals. However, spatial memory ability in squamate reptiles has been seen as possible, at best, or non-existent, at worst. Of the few previous studies testing for spatial memory in squamates, some have found no evidence of spatial memory while two studies have found evidence of spatial memory in snakes, but have been criticized based on methodological issues. We used the Barnes maze, a common paradigm to test spatial memory abilities in mammals, to test for spatial memory abilities in the side-blotched lizard (Uta stansburiana). We found the existence of spatial memory in this species using this spatial task. Thus, our study supports the existence of spatial memory in this squamate reptile species and seeks to parsimoniously align this species with the diverse taxa that demonstrate spatial memory ability.

  14. How Attention Affects Spatial Resolution

    PubMed Central

    Carrasco, Marisa; Barbot, Antoine

    2015-01-01

    We summarize and discuss a series of psychophysical studies on the effects of spatial covert attention on spatial resolution, our ability to discriminate fine patterns. Heightened resolution is beneficial in most, but not all, visual tasks. We show how endogenous attention (voluntary, goal driven) and exogenous attention (involuntary, stimulus driven) affect performance on a variety of tasks mediated by spatial resolution, such as visual search, crowding, acuity, and texture segmentation. Exogenous attention is an automatic mechanism that increases resolution regardless of whether it helps or hinders performance. In contrast, endogenous attention flexibly adjusts resolution to optimize performance according to task demands. We illustrate how psychophysical studies can reveal the underlying mechanisms of these effects and allow us to draw linking hypotheses with known neurophysiological effects of attention. PMID:25948640

  15. Thalamic role in spatial memory.

    PubMed

    Greene, E; Naranjo, J N

    1986-02-01

    The contribution of structures in the limbic diencephalon to spatial memory function was investigated. Rats with lesions of either the anteroventral thalamus, anteromedial thalamus, dorsomedial thalamus or mammillary bodies were compared in their ability to perform a delayed alternation task. The results indicate the ablation of the thalamic nuclei did not impair delayed-alternation memory, but there was impairment following damage to the mammillary bodies. Placement of the discrete lesions was verified using Nissl sections and by tracing the pattern of projections using a silver degeneration stain. The results suggest that individual thalamic nuclei are not essential in the storage and/or retrieval of spatial memory. The data are discussed in terms of spatial deficits resulting from damage to the hippocampus proper or to the pathways connecting it to other brain structures.

  16. Constructing Spatial Meaning: Spatial Affordances in Museum Design

    ERIC Educational Resources Information Center

    Wineman, Jean D.; Peponis, John

    2010-01-01

    Informal education in museums is structured through movement in space. This article summarizes a range of research that examines the role of spatial layout in shaping the ways in which visitors explore, engage, and understand museums and museum exhibitions. It is demonstrated that behavior patterns are systematically linked to spatial…

  17. Generating mixtures of spatial qubits

    NASA Astrophysics Data System (ADS)

    Lima, G.; Torres-Ruiz, F. A.; Neves, Leonardo; Delgado, A.; Saavedra, C.; Pádua, S.

    2008-10-01

    In a recent letter [L. Neves, G. Lima, J.G. Aguirre Gómez, C.H. Monken, C. Saavedra, S. Pádua, Phys. Rev. Lett. 94 (2005) 100501], we presented a scheme for generating pure entangled states of spatial qudits ( D-dimensional quantum systems) by using the momentum transverse correlation of the parametric down-converted photons. In this work, we discuss a generalization of this process to enable the creation of mixed states. With the technique proposed we experimentally generated a mixture of two spatial qubits.

  18. Optimization of spatial complex networks

    NASA Astrophysics Data System (ADS)

    Guillier, S.; Muñoz, V.; Rogan, J.; Zarama, R.; Valdivia, J. A.

    2017-02-01

    First, we estimate the connectivity properties of a predefined (fixed node locations) spatial network which optimizes a connectivity functional that balances construction and transportation costs. In this case we obtain a Gaussian distribution for the connectivity. However, when we consider these spatial networks in a growing process, we obtain a power law distribution for the connectivity. If the transportation costs in the functional involve the shortest geometrical path, we obtain a scaling exponent γ = 2.5. However, if the transportation costs in the functional involve just the shortest path, we obtain γ = 2.2. Both cases may be useful to analyze in some real networks.

  19. Spatial Encryption under Simpler Assumption

    NASA Astrophysics Data System (ADS)

    Zhou, Muxin; Cao, Zhenfu

    Spatial encryption was first proposed by Boneh and Hamburg. They showed that many useful encryption systems can be derived from it. In this paper, we describe two variants of spatial encryption. First we present a scheme that can be proved to be secure under the decisional bilinear Diffie-Hellman assumption, which is much simpler than the BDHE assumption used by Boneh and Hamburg. However, as a compromise, our ciphertext size and private key size are larger. We also discuss some techniques to shrink the private key of this scheme in a real application. Finally, we provide a hybrid construction which allows an optimal tradeoff between efficiency and security.

  20. Fostering Spatial vs. Metric Understanding in Geometry

    ERIC Educational Resources Information Center

    Kinach, Barbara M.

    2012-01-01

    Learning to reason spatially is increasingly recognized as an essential component of geometry education. Generally taken to be the "ability to represent, generate, transform, communicate, document, and reflect on visual information," "spatial reasoning" uses the spatial relationships between objects to form ideas. Spatial thinking takes a variety…

  1. Spatial interferometry in optical astronomy

    NASA Technical Reports Server (NTRS)

    Gezari, Daniel Y.; Roddier, Francois; Roddier, Claude

    1990-01-01

    A bibliographic guide is presented to publications of spatial interferometry techniques applied to optical astronomy. Listings appear in alphabetical order, by first author, as well as in specific subject categories listed in chronological order, including imaging theory and speckle interferometry, experimental techniques, and observational results of astronomical studies of stars, the Sun, and the solar system.

  2. Characterization of Spatial Memory Reconsolidation

    ERIC Educational Resources Information Center

    De Jaeger, Xavier; Courtey, Julie; Brus, Maïna; Artinian, Julien; Villain, Hélène; Bacquié, Elodie; Roullet, Pascal

    2014-01-01

    Reconsolidation is necessary for the restabilization of reactivated memory traces. However, experimental parameters have been suggested as boundary conditions for this process. Here we investigated the role of a spatial memory trace's age, strength, and update on the reconsolidation process in mice. We first found that protein synthesis is…

  3. Spatial Grouping Determines Temporal Integration

    ERIC Educational Resources Information Center

    Hermens, Frouke; Scharnowski, Frank; Herzog, Michael H.

    2009-01-01

    To make sense out of a continuously changing visual world, people need to integrate features across space and time. Despite more than a century of research, the mechanisms of features integration are still a matter of debate. To examine how temporal and spatial integration interact, the authors measured the amount of temporal fusion (a measure of…

  4. Spatial Clustering during Memory Search

    ERIC Educational Resources Information Center

    Miller, Jonathan F.; Lazarus, Eben M.; Polyn, Sean M.; Kahana, Michael J.

    2013-01-01

    In recalling a list of previously experienced items, participants are known to organize their responses on the basis of the items' semantic and temporal similarities. Here, we examine how spatial information influences the organization of responses in free recall. In Experiment 1, participants studied and subsequently recalled lists of landmarks.…

  5. Spatial Visualization by Isometric View

    ERIC Educational Resources Information Center

    Yue, Jianping

    2007-01-01

    Spatial visualization is a fundamental skill in technical graphics and engineering designs. From conventional multiview drawing to modern solid modeling using computer-aided design, visualization skills have always been essential for representing three-dimensional objects and assemblies. Researchers have developed various types of tests to measure…

  6. How Infants Encode Spatial Extent

    ERIC Educational Resources Information Center

    Duffy, Sean; Huttenlocher, Janellen; Levine, Susan; Duffy, Renee

    2005-01-01

    This study explores how infants encode an object's spatial extent. We habituated 6.5-month-old infants to a dowel inside a container and then tested whether they dishabituate to a change in absolute size when the relation between dowel and container is held constant (by altering the size of both container and dowel) and when the relation changes…

  7. Neurophysiological Factors in Spatial Development.

    ERIC Educational Resources Information Center

    Harris, Lauren Jay

    Some of the major lines of investigation that point to neurophysiological factors in spatial skill are presented. These lines include: the two hemispheres of the brain, recent studies, tachistoscopic studies, morphological differences between the cerebral hemispheres, Geschwind and Levitsky's discovery, cerebral dominance re-examined, sex…

  8. Contour integration across spatial frequency.

    PubMed

    Persike, Malte; Olzak, Lynn A; Meinhardt, Günter

    2009-12-01

    Association field models of contour integration suggest that local band-pass elements are spatially grouped to global contours within limited bands of spatial frequency (Field, Hayes, & Hess, 1993). While results for local orientation and spacing variation render support for AF models, effects of spatial frequency (SF) have rarely been addressed. To explore whether contour integration occurs across SF, we studied human contour detection in Gabor random fields with SF jitter along the contour, and in the embedding field. Results show no impairment of contour detection when the contour elements are 1.25 octaves apart. Even with a SF separation of 2.25 octaves there is only moderate impairment. Because SF tuning functions measured for contextual interactions of neighbored single band-pass elements indicate much smaller bandwidths (Polat & Sagi, 1993), the results imply that contour integration cannot rest solely on local locking among neighbored orientation and SF tuned mechanisms. Robustness across spatial frequency, and across color and depth, as found recently, indicates that local orientation based grouping integrates across other basic features. This suggests an origin in not too distal brain regions.

  9. Revoicing Classrooms: A Spatial Manifesto

    ERIC Educational Resources Information Center

    Fisher, Kenn

    2004-01-01

    Why is the physical learning environment in schools largely ignored by teachers within pedagogical practice? The cellular classroom has remained seemingly immutable since the Industrial Revolution, with spatiality playing a silent and subconscious role in schooling other than related to concerns around surveillance. Previous studies have shown…

  10. Building Bridges to Spatial Reasoning

    ERIC Educational Resources Information Center

    Shumway, Jessica F.

    2013-01-01

    Spatial reasoning, which involves "building and manipulating mental representations of two-and three-dimensional objects and perceiving an object from different perspectives" is a critical aspect of geometric thinking and reasoning. Through building, drawing, and analyzing two-and three-dimensional shapes, students develop a foundation…

  11. Learning Anatomy Enhances Spatial Ability

    ERIC Educational Resources Information Center

    Vorstenbosch, Marc A. T. M.; Klaassen, Tim P. F. M.; Donders, A. R. T.; Kooloos, Jan G. M.; Bolhuis, Sanneke M.; Laan, Roland F. J. M.

    2013-01-01

    Spatial ability is an important factor in learning anatomy. Students with high scores on a mental rotation test (MRT) systematically score higher on anatomy examinations. This study aims to investigate if learning anatomy also oppositely improves the MRT-score. Five hundred first year students of medicine ("n" = 242, intervention) and…

  12. Classification of spatially unresolved objects

    NASA Technical Reports Server (NTRS)

    Nalepka, R. F.; Horwitz, H. M.; Hyde, P. D.; Morgenstern, J. P.

    1972-01-01

    A proportion estimation technique for classification of multispectral scanner images is reported that uses data point averaging to extract and compute estimated proportions for a single average data point to classify spatial unresolved areas. Example extraction calculations of spectral signatures for bare soil, weeds, alfalfa, and barley prove quite accurate.

  13. Spatial synchrony in cisco recruitment

    USGS Publications Warehouse

    Myers, Jared T.; Yule, Daniel L.; Jones, Michael L.; Ahrenstorff, Tyler D.; Hrabik, Thomas R.; Claramunt, Randall M.; Ebener, Mark P.; Berglund, Eric K.

    2015-01-01

    We examined the spatial scale of recruitment variability for disparate cisco (Coregonus artedi) populations in the Great Lakes (n = 8) and Minnesota inland lakes (n = 4). We found that the scale of synchrony was approximately 400 km when all available data were utilized; much greater than the 50-km scale suggested for freshwater fish populations in an earlier global analysis. The presence of recruitment synchrony between Great Lakes and inland lake cisco populations supports the hypothesis that synchronicity is driven by climate and not dispersal. We also found synchrony in larval densities among three Lake Superior populations separated by 25–275 km, which further supports the hypothesis that broad-scale climatic factors are the cause of spatial synchrony. Among several candidate climate variables measured during the period of larval cisco emergence, maximum wind speeds exhibited the most similar spatial scale of synchrony to that observed for cisco. Other factors, such as average water temperatures, exhibited synchrony on broader spatial scales, which suggests they could also be contributing to recruitment synchrony. Our results provide evidence that abiotic factors can induce synchronous patterns of recruitment for populations of cisco inhabiting waters across a broad geographic range, and show that broad-scale synchrony of recruitment can occur in freshwater fish populations as well as those from marine systems.

  14. Spatial remapping of tactile events

    PubMed Central

    Azañón, Elena

    2008-01-01

    During the apparently mindless act of localizing a tactile sensation, our brain must realign its initial spatial representation (somatotopicaly arranged) according to current body posture (arising from proprioception, vision and even audition).1–3 We have recently illustrated4 the temporal course of this recoding of tactile space from somatotopic to external coordinates using a crossmodal cueing psychophysical paradigm5,6 where behavioral reactions to visual targets are evaluated as a function of the location of irrelevant tactile cues. We found that the tactile events are initially represented in terms of a fleeting, non-conscious but nevertheless behaviorally consequential somatotopic format, which is quickly replaced by the representations referred to external spatial locations that prevail in our everyday experience. In this addendum, we test the intuition that frequent changes in body posture will make it harder to update the spatial remapping system and thus, produce stronger psychophysical correlates of the initial somatotopically-based spatial representations. Contrary to this expectation, however, we found no evidence for a modulation when preventing adaptation to a body posture. PMID:19704788

  15. Spatial auditory processing in pinnipeds

    NASA Astrophysics Data System (ADS)

    Holt, Marla M.

    Given the biological importance of sound for a variety of activities, pinnipeds must be able to obtain spatial information about their surroundings thorough acoustic input in the absence of other sensory cues. The three chapters of this dissertation address spatial auditory processing capabilities of pinnipeds in air given that these amphibious animals use acoustic signals for reproduction and survival on land. Two chapters are comparative lab-based studies that utilized psychophysical approaches conducted in an acoustic chamber. Chapter 1 addressed the frequency-dependent sound localization abilities at azimuth of three pinniped species (the harbor seal, Phoca vitulina, the California sea lion, Zalophus californianus, and the northern elephant seal, Mirounga angustirostris). While performances of the sea lion and harbor seal were consistent with the duplex theory of sound localization, the elephant seal, a low-frequency hearing specialist, showed a decreased ability to localize the highest frequencies tested. In Chapter 2 spatial release from masking (SRM), which occurs when a signal and masker are spatially separated resulting in improvement in signal detectability relative to conditions in which they are co-located, was determined in a harbor seal and sea lion. Absolute and masked thresholds were measured at three frequencies and azimuths to determine the detection advantages afforded by this type of spatial auditory processing. Results showed that hearing sensitivity was enhanced by up to 19 and 12 dB in the harbor seal and sea lion, respectively, when the signal and masker were spatially separated. Chapter 3 was a field-based study that quantified both sender and receiver variables of the directional properties of male northern elephant seal calls produce within communication system that serves to delineate dominance status. This included measuring call directivity patterns, observing male-male vocally-mediated interactions, and an acoustic playback study

  16. Parcellating connectivity in spatial maps

    PubMed Central

    Beck, Diane M.; Fei-Fei, Li

    2015-01-01

    A common goal in biological sciences is to model a complex web of connections using a small number of interacting units. We present a general approach for dividing up elements in a spatial map based on their connectivity properties, allowing for the discovery of local regions underlying large-scale connectivity matrices. Our method is specifically designed to respect spatial layout and identify locally-connected clusters, corresponding to plausible coherent units such as strings of adjacent DNA base pairs, subregions of the brain, animal communities, or geographic ecosystems. Instead of using approximate greedy clustering, our nonparametric Bayesian model infers a precise parcellation using collapsed Gibbs sampling. We utilize an infinite clustering prior that intrinsically incorporates spatial constraints, allowing the model to search directly in the space of spatially-coherent parcellations. After showing results on synthetic datasets, we apply our method to both functional and structural connectivity data from the human brain. We find that our parcellation is substantially more effective than previous approaches at summarizing the brain’s connectivity structure using a small number of clusters, produces better generalization to individual subject data, and reveals functional parcels related to known retinotopic maps in visual cortex. Additionally, we demonstrate the generality of our method by applying the same model to human migration data within the United States. This analysis reveals that migration behavior is generally influenced by state borders, but also identifies regional communities which cut across state lines. Our parcellation approach has a wide range of potential applications in understanding the spatial structure of complex biological networks. PMID:25737822

  17. Parallels between Spatial Cognition and Spatial Language: Evidence from Williams Syndrome

    ERIC Educational Resources Information Center

    Landau, B.; Hoffman, J.E.

    2005-01-01

    Does the acquisition of spatial language always reflect the characteristics of non-linguistic spatial representation? We explored this question by examining spatial representation and spatial language among children and adults with Williams syndrome, a rare genetic syndrome that gives rise to a pattern of severe spatial impairment together with…

  18. The Role of Spatial Ability and Strategy Preference for Spatial Problem Solving in Organic Chemistry

    ERIC Educational Resources Information Center

    Stieff, Mike; Ryu, Minjung; Dixon, Bonnie; Hegarty, Mary

    2012-01-01

    In organic chemistry, spatial reasoning is critical for reasoning about spatial relationships in three dimensions and representing spatial information in diagrams. Despite its importance, little is known about the underlying cognitive components of spatial reasoning and the strategies that students employ to solve spatial problems in organic…

  19. Spatially Characterizing Effective Timber Supply

    NASA Technical Reports Server (NTRS)

    Berry, J. K.; Sailor, J.

    1982-01-01

    The structure of a computer-oriented cartographic model for assessing roundwood supply for generation of base load electricity is discussed. The model provides an analytical procedure for coupling spatial information of harvesting economics and owner willingness to sell stumpages. Supply is characterized in terms of standing timber; of accessibility considering various harvesting and hauling factors; and of availability as affected by ownership and residential patterns. Factors governing accessibility to timber include effective harvesting distance to haulic roads as modified by barriers and slopes. Haul distance is expressed in units that take into account the relative ease of travel along various road types to a central processing facility. Areas of accessible timber are grouped into spatial units, termed 'timbersheds', of common access to particular haul road segments that belong to unique 'transport zones'. Timber availability considerations include size of ownership parcels, housing density and excluded areas. The analysis techniques are demonstrated for a cartographic data base in western Massachusetts.

  20. Multiplicative noise enhances spatial reciprocity

    NASA Astrophysics Data System (ADS)

    Yao, Yao; Chen, Shen-Shen

    2014-11-01

    Recent research has identified the heterogeneity as crucial for the evolution of cooperation in spatial population. However, the influence of heterogeneous noise is still lacking. Inspired by this interesting question, in this work, we try to incorporate heterogeneous noise into the evaluation of utility, where only a proportion of population possesses noise, whose range can also be tuned. We find that increasing heterogeneous noise monotonously promotes cooperation and even translates the full defection phase (of the homogeneous version) into the complete cooperation phase. Moreover, the promotion effect of this mechanism can be attributed to the leading role of cooperators who have the heterogeneous noise. These type of cooperators can attract more agents penetrating into the robust cooperator clusters, which is beyond the text of traditional spatial reciprocity. We hope that our work may shed light on the understanding of the cooperative behavior in the society.

  1. An improved pinhole spatial filter

    SciTech Connect

    Estabrook, K.; Celliers, P.; Murray, J.; Wallace, R.; Stone, G.; Van Wonterghem, B.; MacGowan, B.; Da Silva, L.; Hunt, J.; Manes, K.

    1996-08-21

    Lasers generate phase aberrated light that can damage laser glass, frequency conversion crystals, lenses, and mirror coatings and can also reduce extractable energy and power. Spatial pinhole filters can partly eliminate such ``hot spots.`` Problems are that the pinhole closes during the laser pulse and has to be made too large initially. Debris from the pinhole can coat or damage spatial filter lenses. This paper presents a novel design for a more robust pinhole filter. Phase distorted (hot spot) light refracts at grazing incidence by plasma on the wall of a funnel shaped filter resulting in less absorption and debris. Refracted light absorbs at low intensities on the vacuum wall. We present 2D hydrodynamic computer simulations and compare the two types of filters with experiment.

  2. Micropolar continuum in spatial description

    NASA Astrophysics Data System (ADS)

    Ivanova, Elena A.; Vilchevskaya, Elena N.

    2016-11-01

    Within the spatial description, it is customary to refer thermodynamic state quantities to an elementary volume fixed in space containing an ensemble of particles. During its evolution, the elementary volume is occupied by different particles, each having its own mass, tensor of inertia, angular and linear velocities. The aim of the present paper is to answer the question of how to determine the inertial and kinematic characteristics of the elementary volume. In order to model structural transformations due to the consolidation or defragmentation of particles or anisotropic changes, one should consider the fact that the tensor of inertia of the elementary volume may change. This means that an additional constitutive equation must be formulated. The paper suggests kinetic equations for the tensor of inertia of the elementary volume. It also discusses the specificity of the inelastic polar continuum description within the framework of the spatial description.

  3. Spatial prediction and ordinary kriging

    SciTech Connect

    Cressie, N.

    1988-05-01

    Suppose data /Z(s/sub i/):i = 1,...,n/ are observed at spatial locations /s/sub i/:i = 1,...,n/. From these data, an unknown Z(s/sub 0/) is to be predicted at a known location s/sub 0/, or, if Z(s/sub 0/) has a component of measurement error, then a smooth version S(s/sub 0/) should be predicted. This article considers the assumptions needed to carry out the spatial prediction using ordinary kriging, and looks at how nugget effect, range, and sill of the variogram affect the predictor. It is concluded that certain commonly held interpretations of these variogram parameters should be modified.

  4. Sustainable Development and Spatial Inhomogeneities

    NASA Astrophysics Data System (ADS)

    Weisbuch, Gérard

    2013-05-01

    Historical data, theory and computer simulations support a connection between growth and economic inequality. Our present world with large regional differences in economic activity is a result of fast economic growth during the last two centuries. Because of limits to growth we might expect a future world to develop differently with far less growth. The question that we here address is: "Would a world with a sustainable economy be less unequal?" We then develop integrated spatial economic models based on limited resources consumption and technical knowledge accumulation and study them by the way of computer simulations. When the only coupling between world regions is diffusion we do not observe any spatial unequality. By contrast, highly localized economic activities are maintained by global market mechanisms. Structures sizes are determined by transportation costs. Wide distributions of capital and production are also predicted in this regime.

  5. Spatial Decision Support Workshop 2011

    DTIC Science & Technology

    2011-01-01

    report are those of the author(s) and should not contrued as an official Department of the Army position, policy or decision, unless so designated by...and temporal development of phenomena and processes ;  Complex multi-dimensional and heterogeneous data describing decision situations;  Large or...information is an integral part of DoD operations and installation management. Spatial decision support processes and systems combine GIS and other

  6. Spatial Hearing in Echoic Environments

    DTIC Science & Technology

    2008-02-29

    target from masker and thereby support selective attention. (Published in 2005 in Acta Acustica united with Acustica [J3]) A paper was published...localization. (Published in 2008 in Acta Acustica united with Acustica [J10]) Interest in the perceptual consequences of reverberation on perception...E Larson and Satyavarta (2005). “Top-down and bottom-up influences on spatial unmasking,” Acta Acustica united with Acustica . [J4] Naka, Y, A

  7. Mechanisms for Human Spatial Competence

    DTIC Science & Technology

    2007-01-01

    experience. To take a famous example from Stevens & Coupe [43], when studying a map of the United States, San Diego will tend to be encoded with respect to...Relations. Cognitive Psychology 18, 87–121 (1986) 43. Stevens , A., Coupe, P.: Distortions in Judged Spatial Relations. Cognitive Psychology 10, 422...Model of Human Attentional Networks. Cognitive Systems Research 5, 119–134 (2004) 60. Finke, R.A., Pinker , S., Farah, M.: Reinterpreting Visual

  8. Spatial Light Rebroadcaster Architecture Study

    DTIC Science & Technology

    1992-12-01

    linear photo-diode array (input side of spatial light rebroadcaster). Additional raytraces are shown in Fig. 3.2-3. The mask layout is shown in Fig...actual optical system use optical raytracing design 3 software. The literature generally shows only very simplified, schematic drawings of cylindrical...with low contrast irnfrared images and I speckled radar images. It has also been employed extensively in medicai image processing to, for example

  9. Entropy, complexity, and spatial information

    NASA Astrophysics Data System (ADS)

    Batty, Michael; Morphet, Robin; Masucci, Paolo; Stanilov, Kiril

    2014-10-01

    We pose the central problem of defining a measure of complexity, specifically for spatial systems in general, city systems in particular. The measures we adopt are based on Shannon's (in Bell Syst Tech J 27:379-423, 623-656, 1948) definition of information. We introduce this measure and argue that increasing information is equivalent to increasing complexity, and we show that for spatial distributions, this involves a trade-off between the density of the distribution and the number of events that characterize it; as cities get bigger and are characterized by more events—more places or locations, information increases, all other things being equal. But sometimes the distribution changes at a faster rate than the number of events and thus information can decrease even if a city grows. We develop these ideas using various information measures. We first demonstrate their applicability to various distributions of population in London over the last 100 years, then to a wider region of London which is divided into bands of zones at increasing distances from the core, and finally to the evolution of the street system that characterizes the built-up area of London from 1786 to the present day. We conclude by arguing that we need to relate these measures to other measures of complexity, to choose a wider array of examples, and to extend the analysis to two-dimensional spatial systems.

  10. Maritime Spatial Planning in Cyprus

    NASA Astrophysics Data System (ADS)

    Hadjimitsis, Diofantos; Agapiou, Athos; Themistocleous, Kyriakos; Mettas, Christodoulos; Evagorou, Evagoras; Soulis, Giorgos; Xagoraris, Zafeiris; Pilikou, Maria; Aliouris, Kyriakos; Ioannou, Nicolas

    2016-01-01

    Spatial Planning is a critical tool for land management and is extensively used in all developed nations. The Marine Spatial Planning (MSP), at the European Union (EU) level, is based on Directive 2014/89/EU of the European Parliament and Council of 23rd July 2014 which establishes a common framework for MSP in the EU, which each Member State is called to apply in relation to the maritime space under its jurisdiction (marine waters). In this paper the overall results from the "Cross-Border Cooperation for the development of Marine Spatial Planning" project are presented for the area of Cyprus. A variety of activities fall within the MSP such as maritime transport routes and traffic flows, exploration, exploitation and extraction of energy resources, tourism, underwater cultural heritage etc. In addition, the legal framework, activities maps are also shown. The variety of conflicts maps for the area of Limassol are illustrated both in 2D and 3D. A hypothetical scenario of Limassol town in Cyprus as an energy center is presented based on the overall results. The paper ends with some conclusions regarding the framework of MSP in Cyprus.

  11. Bootstrap percolation on spatial networks

    NASA Astrophysics Data System (ADS)

    Gao, Jian; Zhou, Tao; Hu, Yanqing

    2015-10-01

    Bootstrap percolation is a general representation of some networked activation process, which has found applications in explaining many important social phenomena, such as the propagation of information. Inspired by some recent findings on spatial structure of online social networks, here we study bootstrap percolation on undirected spatial networks, with the probability density function of long-range links’ lengths being a power law with tunable exponent. Setting the size of the giant active component as the order parameter, we find a parameter-dependent critical value for the power-law exponent, above which there is a double phase transition, mixed of a second-order phase transition and a hybrid phase transition with two varying critical points, otherwise there is only a second-order phase transition. We further find a parameter-independent critical value around -1, about which the two critical points for the double phase transition are almost constant. To our surprise, this critical value -1 is just equal or very close to the values of many real online social networks, including LiveJournal, HP Labs email network, Belgian mobile phone network, etc. This work helps us in better understanding the self-organization of spatial structure of online social networks, in terms of the effective function for information spreading.

  12. Spatial Reasoning in Tenejapan Mayans

    PubMed Central

    Li, Peggy; Abarbanell, Linda; Gleitman, Lila; Papafragou, Anna

    2011-01-01

    Language communities differ in their stock of reference frames (coordinate systems for specifying locations and directions). English typically uses egocentrically defined axes (e.g., “left-right”), especially when describing small-scale relationships. Other languages such as Tseltal Mayan prefer to use geocentrically-defined axes (e.g., “north-south”) and do not use any type of projective body-defined axes. It has been argued that the availability of specific frames of reference in language determines the availability or salience of the corresponding spatial concepts. In four experiments, we explored this hypothesis by testing Tseltal speakers’ spatial reasoning skills. Whereas most prior tasks in this domain were open-ended (allowing several correct solutions), the present tasks required a unique solution that favored adopting a frame of reference that was either congruent or incongruent with what is habitually lexicalized in the participants’ language. In these tasks, Tseltal speakers easily solved the language-incongruent problems, and performance was generally more robust for these than for the language-congruent problems that favored geocentrically-defined coordinates. We suggest thatlisteners’ probabilistic inferences when instruction is open to more than one interpretation account for why there are greater cross-linguistic differences in the solutions to open-ended spatial problems than to less ambiguous ones. PMID:21481854

  13. Spatial complexity in children's language.

    PubMed

    Weist, R M; Lymburner, N L; Piotrowski, S; Stoddard, J L

    2000-10-01

    The purpose of this research was to explore the properties of locative scenes which influence the sequence of the acquisition of spatial prepositions in English. Children ranging in age from about 2;8 to 5;6 were tested with a comprehension test involving a sentence-picture matching task. The comprehension test contained six kinds of spatial contrasts which were judged to vary in the geometric complexity of the scene. The order of acquisition was as follows: (1) into/out of & onto/off of, (2) in/on, (3) into/onto & out of/off of and through/over (around), (4) between X & Y/Y & Z, and (5) across/along. Complexity depends on a number of factors such as the number of referent objects and the nature of the relationship between the object to be located and the critical feature of the referent object. Prepositions which involve a more complex spatial geometry are more difficult for young children to comprehend. It was argued that the sequence of acquisition is partially determined by the course of conceptual development.

  14. Bootstrap percolation on spatial networks

    PubMed Central

    Gao, Jian; Zhou, Tao; Hu, Yanqing

    2015-01-01

    Bootstrap percolation is a general representation of some networked activation process, which has found applications in explaining many important social phenomena, such as the propagation of information. Inspired by some recent findings on spatial structure of online social networks, here we study bootstrap percolation on undirected spatial networks, with the probability density function of long-range links’ lengths being a power law with tunable exponent. Setting the size of the giant active component as the order parameter, we find a parameter-dependent critical value for the power-law exponent, above which there is a double phase transition, mixed of a second-order phase transition and a hybrid phase transition with two varying critical points, otherwise there is only a second-order phase transition. We further find a parameter-independent critical value around −1, about which the two critical points for the double phase transition are almost constant. To our surprise, this critical value −1 is just equal or very close to the values of many real online social networks, including LiveJournal, HP Labs email network, Belgian mobile phone network, etc. This work helps us in better understanding the self-organization of spatial structure of online social networks, in terms of the effective function for information spreading. PMID:26423347

  15. Spatial Distributions of Young Stars

    NASA Astrophysics Data System (ADS)

    Kraus, Adam L.; Hillenbrand, Lynne A.

    2008-10-01

    We analyze the spatial distribution of young stars in Taurus-Auriga and Upper Sco, as determined from the two-point correlation function (i.e., the mean surface density of neighbors). The corresponding power-law fits allow us to determine the fractal dimensions of each association's spatial distribution, measure the stellar velocity dispersions, and distinguish between the bound binary population and chance alignments of members. We find that the fractal dimension of Taurus is D ~ 1.05, consistent with its filamentary structure. The fractal dimension of Upper Sco may be even shallower (D ~ 0.7), but this fit is uncertain due to the limited area and possible spatially variable incompleteness. We also find that random stellar motions have erased all primordial structure on scales of lsim0.07° in Taurus and lsim1.7° in Upper Sco; given ages of ~1 and ~5 Myr, the corresponding internal velocity dispersions are ~0.2 and ~1.0 km s-1, respectively. Finally, we find that binaries can be distinguished from chance alignments at separations of lsim120'' (17,000 AU) in Taurus and lsim75'' (11,000 AU) in Upper Sco. The binary populations in these associations that we previously studied, spanning separations of 3''-30'', is dominated by binary systems. However, the few lowest mass pairs (Mprim <~ 0.3 M⊙) might be chance alignments.

  16. Giving Spatial Perception Our Full Attention: Are We Reaching Spatial Learners?

    ERIC Educational Resources Information Center

    Lord, Thomas R.; Clausen-May, Tandi

    2002-01-01

    Explains spatial perception and how it is influential on a student's academic abilities. Discusses how spatial thinkers conduct experiments in science learning and how to teach using spatial thinkers' participation. (YDS)

  17. Spatial Moran models, II: cancer initiation in spatially structured tissue

    PubMed Central

    Foo, J; Leder, K

    2016-01-01

    We study the accumulation and spread of advantageous mutations in a spatial stochastic model of cancer initiation on a lattice. The parameters of this general model can be tuned to study a variety of cancer types and genetic progression pathways. This investigation contributes to an understanding of how the selective advantage of cancer cells together with the rates of mutations driving cancer, impact the process and timing of carcinogenesis. These results can be used to give insights into tumor heterogeneity and the “cancer field effect,” the observation that a malignancy is often surrounded by cells that have undergone premalignant transformation. PMID:26126947

  18. MAPPING SPATIAL THEMATIC ACCURACY WITH FUZZY SETS

    EPA Science Inventory

    Thematic map accuracy is not spatially homogenous but variable across a landscape. Properly analyzing and representing spatial pattern and degree of thematic map accuracy would provide valuable information for using thematic maps. However, current thematic map accuracy measures (...

  19. Liquid crystal television spatial light modulators

    NASA Technical Reports Server (NTRS)

    Liu, Hua-Kuang; Chao, Tien-Hsin

    1989-01-01

    The spatial light modulation characteristics and capabilities of the liquid crystal television (LCTV) spatial light modulators (SLMs) are discussed. A comparison of Radio Shack, Epson, and Citizen LCTV SLMs is made.

  20. Evolution of cooperation in spatially structured populations

    PubMed

    Brauchli; Killingback; Doebeli

    1999-10-21

    Using a spatial lattice model of the Iterated Prisoner's Dilemma we studied the evolution of cooperation within the strategy space of all stochastic strategies with a memory of one round. Comparing the spatial model with a randomly mixed model showed that (1) there is more cooperative behaviour in a spatially structured population, (2) PAVLOV and generous variants of it are very successful strategies in the spatial context and (3) in spatially structured populations evolution is much less chaotic than in unstructured populations. In spatially structured populations, generous variants of PAVLOV are found to be very successful strategies in playing the Iterated Prisoner's Dilemma. The main weakness of PAVLOV is that it is exploitable by defective strategies. In a spatial context this disadvantage is much less important than the good error correction of PAVLOV, and especially of generous PAVLOV, because in a spatially structured population successful strategies always build clusters. Copyright 1999 Academic Press.

  1. Modeling anatomical spatial relations with description logics.

    PubMed Central

    Schulz, S.; Hahn, U.; Romacker, M.

    2000-01-01

    Although spatial relations are essential for the anatomy domain, spatial reasoning is only weakly supported by medical knowledge representation systems. To remedy this shortcoming we express spatial relations that can intuitively be applied to anatomical objects (such as 'disconnected', 'externally connected', 'partial overlap' and 'proper part') within the formal framework of description logics. A special encoding of concept descriptions (in terms of SEP triplets) allows us to emulate spatial reasoning by classification-based reasoning. PMID:11079990

  2. Spatial Coherence of Synchrotron Radiation

    SciTech Connect

    Marchesini, S; Coisson, R

    2003-10-30

    Synchrotron Radiation (SR) has been widely used since the 80's as a tool for many applications of UV, soft X rays and hard X rays in condensed matter physics, chemistry and biology. The evolution of SR sources towards higher brightness has led to the design of low-emittance electron storage rings (emittance is the product of beam size and divergence), and the development of special source magnetic structures, as undulators. This means that more and more photons are available on a narrow bandwidth and on a small collimated beam; in other words there is the possibility of getting a high power in a coherent beam. In most applications, a monochromator is used, and the temporal coherence of the light is given by the monochromator bandwidth. With smaller and smaller sources, even without the use of collimators, the spatial coherence of the light has become appreciable, first in the UV and soft X ray range, and then also with hard X rays. This has made possible new or improved experiments in interferometry, microscopy, holography, correlation spectroscopy, etc. In view of these recent possibilities and applications, it is useful to review some basic concepts about spatial coherence of SR, and its measurement and applications. In particular we show how the spatial coherence properties of the radiation in the far field can be calculated with simple operations from the single-electron amplitude and the electron beam angular and position spreads. The gaussian approximation will be studied in detail for a discussion of the properties of the far field mutual coherence and the estimate of the coherence widths, and the comparison with the VanCittert-Zernike limit.

  3. Spatial Abilities across the Adult Life Span

    ERIC Educational Resources Information Center

    Borella, Erika; Meneghetti, Chiara; Ronconi, Lucia; De Beni, Rossana

    2014-01-01

    The study investigates age-related effects across the adult life span on spatial abilities (testing subabilities based on a distinction between spatial visualization, mental rotation, and perspective taking) and spatial self-assessments. The sample consisted of 454 participants (223 women and 231 men) from 20 to 91 years of age. Results showed…

  4. Spatializing Critical Education: Progress and Cautions

    ERIC Educational Resources Information Center

    Ferrare, Joseph J.; Apple, Michael W.

    2010-01-01

    Recently critical scholars have shown a renewed interest in spatial relations in educational contexts. In this essay we use selections from Gulson and Symes's edited volume "Spatial theories of education" as a point of departure to examine what spatial analysis can contribute to the critical education traditions. We argue that, when done…

  5. Development: Ages & Stages--Spatial Awareness

    ERIC Educational Resources Information Center

    Poole, Carla; Miller, Susan A.; Church, Ellen Booth

    2006-01-01

    Spatial concepts such as a sense of distance are learned through movement and exploration which is the most effective way for children to gain body awareness and an understanding of spatial relationships. It simultaneously develops muscle strength, coordination, self-confidence, and thinking skills. Spatial awareness can be defined as "an…

  6. Future Teachers' Spatial Thinking Skills and Attitudes

    ERIC Educational Resources Information Center

    Shin, Euikyung E.; Milson, Andrew J.; Smith, Thomas J.

    2016-01-01

    The spatial thinking skills and attitudes of geography majors were compared with those of future teachers majoring in elementary education and secondary social studies education. Scores were obtained for each group on two measures: the spatial skills test and the attitude toward spatial thinking inventory. Mean differences were examined based on…

  7. SPATIAL PREDICTION USING COMBINED SOURCES OF DATA

    EPA Science Inventory

    For improved environmental decision-making, it is important to develop new models for spatial prediction that accurately characterize important spatial and temporal patterns of air pollution. As the U .S. Environmental Protection Agency begins to use spatial prediction in the reg...

  8. Issues of Authenticity of Spatial Data.

    ERIC Educational Resources Information Center

    McGlamery, Patrick

    This paper discusses the authenticity of digital spatial data. The first section describes three formats for digital spatial data: vector, raster, and thematic. The second section addresses the integrity of spatial data, including six possible formats for the same information: (1) aerial photographic prints, time stamped, primary, remotely sensed…

  9. Four-Dimensional Spatial Reasoning in Humans

    ERIC Educational Resources Information Center

    Aflalo, T. N.; Graziano, M. S. A.

    2008-01-01

    Human subjects practiced navigation in a virtual, computer-generated maze that contained 4 spatial dimensions rather than the usual 3. The subjects were able to learn the spatial geometry of the 4-dimensional maze as measured by their ability to perform path integration, a standard test of spatial ability. They were able to travel down a winding…

  10. Development of a Geometric Spatial Visualization Tool

    ERIC Educational Resources Information Center

    Ganesh, Bibi; Wilhelm, Jennifer; Sherrod, Sonya

    2009-01-01

    This paper documents the development of the Geometric Spatial Assessment. We detail the development of this instrument which was designed to identify middle school students' strategies and advancement in understanding of four geometric concept domains (geometric spatial visualization, spatial projection, cardinal directions, and periodic patterns)…

  11. Spatial Memory for Chinese and English.

    ERIC Educational Resources Information Center

    Tavassoli, Nader T.

    2002-01-01

    Investigated spatial memory for written words as a behavioral consequence of verbal processing differences. Across three experiments with Chinese and U.S. college students, spatial memory for real and nonsense words was greater for Chinese logographs than for alphabetic English words. This spatial memory advantage was absent for pictures and…

  12. How Do Children Describe Spatial Relationships?

    ERIC Educational Resources Information Center

    Cox, M. V.; Richardson, J. Ryder

    1985-01-01

    Describes a study of children's production of locative prepositions in order to test H. Clark's hypotheses regarding the acquisition of spatial terms. Subjects were required to describe the spatial arrangement of two balls arranged in each of three spatial dimensions. (SED)

  13. Effect of GIS Learning on Spatial Thinking

    ERIC Educational Resources Information Center

    Lee, Jongwon; Bednarz, Robert

    2009-01-01

    A spatial-skills test is used to examine the effect of GIS learning on the spatial thinking ability of college students. Eighty students at a large state university completed pre- and post- spatial-skills tests administered during the 2003 fall semester. Analysis of changes in the students' test scores revealed that GIS learning helped students…

  14. Sex Differences in Spatial Ability: A Critique.

    ERIC Educational Resources Information Center

    Clear, Sarah-Jane

    1978-01-01

    Explores (1) problems of the validity of tests of spatial ability, and (2) problems of the recessive gene influence theory of the origin of sex differences in spatial ability. Studies of cognitive strategies in spatial problem solving are suggested as a way to further investigate recessive gene influence. (Author/RH)

  15. Teaching the Gifted Visual Spatial Learner

    ERIC Educational Resources Information Center

    Freed, Jeff

    2006-01-01

    In working with right-brained or visual spatial children for the past 20 years, the author has noticed that they all learn in a similar manner. He has also noticed that a high percentage of gifted children are visual spatial learners. The more visual spatial a child is, the higher the potential for school difficulties. Since most teachers are…

  16. Superresolved spatially multiplexed interferometric microscopy.

    PubMed

    Picazo-Bueno, José Ángel; Zalevsky, Zeev; García, Javier; Micó, Vicente

    2017-03-01

    Superresolution capability by angular and time multiplexing is implemented onto a regular microscope. The technique, named superresolved spatially multiplexed interferometric microscopy (S2MIM), follows our previously reported SMIM technique [Opt. Express22, 14929 (2014)OPEXFF1094-408710.1364/OE.22.014929, J. Biomed. Opt.21, 106007 (2016)JBOPFO1083-366810.1117/1.JBO.21.10.106007] improved with superresolved imaging. All together, S2MIM updates a commercially available non-holographic microscope into a superresolved holographic one. Validation is presented for an Olympus BX-60 upright microscope with resolution test targets.

  17. DNA Rearrangements through Spatial Graphs

    NASA Astrophysics Data System (ADS)

    Jonoska, Nataša; Saito, Masahico

    The paper is a short overview of a recent model of homologous DNA recombination events guided by RNA templates that have been observed in certain species of ciliates. This model uses spatial graphs to describe DNA rearrangements and show how gene recombination can be modeled as topological braiding of the DNA. We show that a graph structure, which we refer to as an assembly graph, containing only 1- and 4-valent rigid vertices can provide a physical representation of the DNA at the time of recombination. With this representation, 4-valent vertices correspond to the alignment of the recombination sites, and we model the actual recombination event as smoothing of these vertices.

  18. Spatial heterodyne spectrometer for FLEX

    NASA Astrophysics Data System (ADS)

    Scott, Alan; Zheng, Sheng-Hai; Brown, Stephen; Bell, Andrew

    2007-10-01

    A spatial heterodyne spectrometer (SHS) has significant advantages for high spectral resolution imaging over narrow pre-selected bands compared to traditional solutions. Given comparable optical étendue at R~6500, a field-widened SHS will have a throughput-resolution product ~170 x larger than an air-spaced etalon spectrometer, and ~1000 x larger than a standard grating spectrometer. The monolithic glass Michelson design and lack of moving parts allows maximum stability of spectral calibration over the mission life. For these reasons, SHS offers considerable advantages for the core spectrometer instrument in the European Space Agency's (ESA) Fluorescence Explorer (FLEX) mission.

  19. Approximating spatially exclusive invasion processes

    NASA Astrophysics Data System (ADS)

    Ross, Joshua V.; Binder, Benjamin J.

    2014-05-01

    A number of biological processes, such as invasive plant species and cell migration, are composed of two key mechanisms: motility and reproduction. Due to the spatially exclusive interacting behavior of these processes a cellular automata (CA) model is specified to simulate a one-dimensional invasion process. Three (independence, Poisson, and 2D-Markov chain) approximations are considered that attempt to capture the average behavior of the CA. We show that our 2D-Markov chain approximation accurately predicts the state of the CA for a wide range of motility and reproduction rates.

  20. Spatially confined assembly of nanoparticles.

    PubMed

    Jiang, Lin; Chen, Xiaodong; Lu, Nan; Chi, Lifeng

    2014-10-21

    The ability to assemble NPs into ordered structures that are expected to yield collective physical or chemical properties has afforded new and exciting opportunities in the field of nanotechnology. Among the various configurations of nanoparticle assemblies, two-dimensional (2D) NP patterns and one-dimensional (1D) NP arrays on surfaces are regarded as the ideal assembly configurations for many technological devices, for example, solar cells, magnetic memory, switching devices, and sensing devices, due to their unique transport phenomena and the cooperative properties of NPs in assemblies. To realize the potential applications of NP assemblies, especially in nanodevice-related applications, certain key issues must still be resolved, for example, ordering and alignment, manipulating and positioning in nanodevices, and multicomponent or hierarchical structures of NP assemblies for device integration. Additionally, the assembly of NPs with high precision and high levels of integration and uniformity for devices with scaled-down dimensions has become a key and challenging issue. Two-dimensional NP patterns and 1D NP arrays are obtained using traditional lithography techniques (top-down strategies) or interfacial assembly techniques (bottom-up strategies). However, a formidable challenge that persists is the controllable assembly of NPs in desired locations over large areas with high precision and high levels of integration. The difficulty of this assembly is due to the low efficiency of small features over large areas in lithography techniques or the inevitable structural defects that occur during the assembly process. The combination of self-assembly strategies with existing nanofabrication techniques could potentially provide effective and distinctive solutions for fabricating NPs with precise position control and high resolution. Furthermore, the synergistic combination of spatially mediated interactions between nanoparticles and prestructures on surfaces may play

  1. Spatial confinement of muonium atoms

    NASA Astrophysics Data System (ADS)

    Khaw, K. S.; Antognini, A.; Prokscha, T.; Kirch, K.; Liszkay, L.; Salman, Z.; Crivelli, P.

    2016-08-01

    We report the achievement of spatial confinement of muonium atoms (the bound state of a positive muon and an electron). Muonium emitted into a vacuum from mesoporous silica reflects between two SiO2 confining surfaces separated by 1 mm. From the data, one can extract that the reflection probability on the confining surfaces kept at 100 K is about 90% and the reflection process is well described by a cosine law. This technique enables new experiments with this exotic atomic system and is a very important step towards a measurement of the 1 S -2 S transition frequency using continuous-wave laser spectroscopy.

  2. Motivation sharpens exogenous spatial attention.

    PubMed

    Engelmann, Jan B; Pessoa, Luiz

    2007-08-01

    Although both attention and motivation affect behavior, how these 2 systems interact is currently unknown. To address this question, 2 experiments were conducted in which participants performed a spatially cued forced-choice localization task under varying levels of motivation. Participants were asked to indicate the location of a peripherally cued target while ignoring a distracter. Motivation was manipulated by varying magnitude and valence (reward and punishment) of an incentive linked to task performance. Attention was manipulated via a peripheral cue, which correctly predicted the presence of a target stimulus on 70% of the trials. Taken together, our findings revealed that the signal detection measure, reflecting perceptual sensitivity, increased as a function of incentive value during both valid and invalid trials. In addition, trend analyses revealed a linear increase in detection sensitivity as a function of incentive magnitude for both reward and punishment conditions. Our results suggest that elevated motivation leads to improved efficiency in orienting and reorienting of exogenous spatial attention and that one mechanism by which attention and motivation interact involves the sharpening of attention during motivationally salient conditions.

  3. Spatial phase stepping wavelength meter

    NASA Astrophysics Data System (ADS)

    Surrel, Yves; García-Márquez, Jorge; Fodor, Jozsua; Juncar, Patrick

    2005-03-01

    A new way of evaluating the ratio between a reference wavelength radiation and an unknown wavelength radiation in a two-beam interferometer is proposed here. The advantage of two-beam interferometry is the sinusoidal fringe signal for which precise phase detection algorithms exist. Modern algorithms can cope with different sources of errors, and correct them. We recall the principle of the Michelson-type lambdameter using temporal interference and we introduce the Young-type lambdameter using spatial interference. The Young-type lambdameter is based on the acquisition of the interference pattern from two point sources (e.g. two ends of monomode fibres projected onto a CCD camera). The measurement of an unknown wavelength can be achieved by comparing with a reference wavelength. Accurate interference phase maps can be calculated using spatial phase shifting. In this way, each small group of contiguous pixels acts as a single interferometer, and the whole set of pixels corresponds to many hundreds or thousands of interferometric measurement system units. The analysis of uncertainties shows that resolutions better than 10-7 can be achieved. An advantage of the fibre wavelength metre described here is the measurement velocity that takes only a few seconds.

  4. Spatial curvature falsifies eternal inflation

    SciTech Connect

    Kleban, Matthew; Schillo, Marjorie E-mail: mls604@nyu.edu

    2012-06-01

    Inflation creates large-scale cosmological density perturbations that are characterized by an isotropic, homogeneous, and Gaussian random distribution about a locally flat background. Even in a flat universe, the spatial curvature measured within one Hubble volume receives contributions from long wavelength perturbations, and will not in general be zero. These same perturbations determine the Cosmic Microwave Background (CMB) temperature fluctuations, which are O(10{sup −5}). Consequently, the low-l multipole moments in the CMB temperature map predict the value of the measured spatial curvature Ω{sub k}. On this basis we argue that a measurement of |Ω{sub k}| > 10{sup −4} would rule out slow-roll eternal inflation in our past with high confidence, while a measurement of Ω{sub k} < −10{sup −4} (which is positive curvature, a locally closed universe) rules out false-vacuum eternal inflation as well, at the same confidence level. In other words, negative curvature (a locally open universe) is consistent with false-vacuum eternal inflation but not with slow-roll eternal inflation, and positive curvature falsifies both. Near-future experiments will dramatically extend the sensitivity of Ω{sub k} measurements and constitute a sharp test of these predictions.

  5. Temporal asynchrony and spatial perception

    PubMed Central

    Lev, Maria; Polat, Uri

    2016-01-01

    Collinear facilitation is an enhancement in the visibility of a target by laterally placed iso-oriented flankers in a collinear (COL) configuration. Iso-oriented flankers placed in a non-collinear configuration (side-by-side, SBS) produce less facilitation. Surprisingly, presentation of both configurations simultaneously (ISO-CROSS) abolishes the facilitation rather than increases it - a phenomenon that can’t be fully explained by the spatial properties of the target and flankers. Based on our preliminary data and recent studies, we hypothesized that there might be a novel explanation based on the temporal properties of the excitation and inhibition, resulting in asynchrony between the lateral inputs received from COL and SBS, leading to cancelation of the facilitatory component in ISO-CROSS. We explored this effect using a detection task in humans. The results replicated the previous results showing that the preferred facilitation for COL and SBS was abolished for the ISO-CROSS configuration. However, presenting the SBS flankers, but not the COL flankers 20 msec before ISO-CROSS restored the facilitatory effect. We propose a novel explanation that the perceptual advantage of collinear facilitation may be cancelled by the delayed input from the sides; thus, the final perception is determined by the overall spatial-temporal integration of the lateral interactions. PMID:27460532

  6. Spatial release from informational masking

    NASA Astrophysics Data System (ADS)

    Rakerd, Brad; Aaronson, Neil L.

    2001-05-01

    A new method for investigating spatial release from informational masking was developed and employed in two experiments. The new method is computer controlled and efficient. It employs the versatile coordinate response measure speech stimulus set [Bolia et al., J. Acoust. Soc. Am. 107, 1065 (2000)]. The experiments were conducted in an anechoic room, with a primary loudspeaker in front of the listener and a secondary loudspeaker at 60 deg to the right. Target messages were presented from the primary speaker only. For a standard, distractor messages, simultaneous with the target, were also presented from the primary speaker only. Spatial release was measured by presenting the distractors from both primary and secondary speakers with a temporal offset. Experiment 1 fixed the offset (secondary leading, +4 ms) and varied the number of distractors (1 to 3) and the target-to-distractor ratio (-12 to +4 dB). Masking release, sometimes as large as 10 dB, was found for all combinations of these variables. Experiment 2 varied the offset over a wide range of values. Substantial release from masking was found for both positive and negative offsets, but only in the range in which speech echoes are suppressed (<50 ms). [Work supported by NIDCD grant DC 00181.

  7. Spatial Reorientation Following Space Flight

    NASA Technical Reports Server (NTRS)

    2003-01-01

    The short-arm centrifuge subjects an astronaut to conflicting sensory input and study the astronaut's perception of motion. It is one of several instruments used in the Spatial Reorientation Following Space Flight investigation to be conducted after astronauts return to Earth. During space flight, the vestibular organs no longer respond in a familiar way. Instead, inputs from the irner ear do not match those coming from the eyes. While on Earth, you can open your eyes to see if you truly are spinning, but astronauts do not have this luxury. Astronauts can see the floor, but have no sense of down; when they bend their heads forward, the otoliths are not stimulated properly. This state, called sensory conflict, must be resolved by the brain to maintain orientation. When they first return to Earth, astronauts are again disoriented because of sensory conflict. They undergo a period of spatial reorientation, as their brains reconcile what their eyes see and what their vestibular system senses. Recovery can take anywhere from hours to days depending on the length of the mission. Principal Investigator: Dr. William Paloski, Johnson Space Center, Houston, TX.

  8. Spatial Reorientation Following Space Flight

    NASA Technical Reports Server (NTRS)

    2003-01-01

    The short-arm centrifuge subjects an astronaut to conflicting sensory input and study the astronaut's perception of motion. It is one of several instruments used in the Spatial Reorientation Following Space Flight investigation to be conducted on crewmembers. During space flight, the vestibular organs no longer respond in a familiar way. Instead, inputs from the irner ear do not match those coming from the eyes. While on Earth, you can open your eyes to see if you truly are spinning, but astronauts do not have this luxury. Astronauts can see the floor, but have no sense of down; when they bend their heads forward, the otoliths are not stimulated properly. This state, called sensory conflict, must be resolved by the brain to maintain orientation. When they first return to Earth, astronauts are again disoriented because of sensory conflict. They undergo a period of spatial reorientation, as their brains reconcile what their eyes see and what their vestibular system senses. Recovery can take anywhere from hours to days depending on the length of the mission. Principal Investigator: Dr. William Paloski, Johnson Space Center, Houston, TX.

  9. On aggregation in spatial econometric modelling

    NASA Astrophysics Data System (ADS)

    Paelinck, Jean H. P.

    The spatial aggregation problem - also termed the modifiable areal unit problem - has attracted regular attention in spatial statistics and econometrics. In this study econometric aggregation analysis is used to investigate the formal composition of meso-areal parameters given micro-areal underlying relations with spatial dependence. Impact on stochastic terms (possible meso-areal spatial autocorrelation) is also studied. Finally consequences for meso-areal estimation are derived, the general finding having been that spatial aggregation leads to meso-region specific parameter values, with the estimation problems this implies.

  10. Applying spatial thinking in social science research

    PubMed Central

    Logan, John R.; Zhang, Weiwei; Xu, Hongwei

    2010-01-01

    Spatial methods that build upon Geographic Information Systems are spreading quickly across the social sciences. This essay points out that the appropriate use of spatial tools requires more careful thinking about spatial concepts. As easy as it is now to measure distance, it is increasingly important to understand what we think it represents. To interpret spatial patterns, we need spatial theories. We review here a number of key concepts as well as some of the methodological approaches that are now at the disposal of researchers, and illustrate them with studies that reflect the very wide range of problems that use these tools. PMID:20431703

  11. The Spatial Scaffold: The Effects of Spatial Context on Memory for Events

    ERIC Educational Resources Information Center

    Robin, Jessica; Wynn, Jordana; Moscovitch, Morris

    2016-01-01

    Events always unfold in a spatial context, leading to the claim that it serves as a scaffold for encoding and retrieving episodic memories. The ubiquitous co-occurrence of spatial context with events may induce participants to generate a spatial context when hearing scenarios of events in which it is absent. Spatial context should also serve as an…

  12. Spatial data interoperability for multi-platform GIS based on Oracle Spatial

    NASA Astrophysics Data System (ADS)

    Xia, Yu; Zhu, Xinyan

    2006-10-01

    Spatial data sharing among multiple GIS (Geographic Information System) platforms is a fundamental requirement of many GIS applications, yet conventional methods of spatial data interoperability don't adequately consider practical application circumstance, which now becomes a primary barrier to more efficient spatial data sharing among multiple GIS platforms. In this paper, after analyzing the disadvantages of conventional methods and the causation of the disadvantages, and analyzing the principle of spatial data access of ArcGIS, MapInfo and GeoStar based on Oracle Spatial storage, the authors propose a new spatial data interoperability method called Different meta information and Same spatial data Method. This method is based on Oracle Spatial, through which spatial data interoperability for multi-platform of GIS is available. The results of experiments demonstrate that this method is a new simple practical approach adapted for current application circumstance, and it provides us a new idea for spatial data interoperability.

  13. The anatomy of spatial neglect

    PubMed Central

    Karnath, Hans-Otto; Rorden, Christopher

    2011-01-01

    Neglect is often perceived as a “heterogeneous collection of symptoms” with controversial anatomical correlates. However, a clear framework for core and satellite symptoms exists. Here we review the literature when viewed from the perspective of these different syndromes, and find clear pattern of anatomical injury. Specifically, the combined symptoms of biased gaze direction and search – with no awareness of these symptoms – is seen following structural damage to (particularly right hemisphere) perisylvian regions. Object centered deficits such as biased line bisection are due to more posterior (and possibly inferior) injury. Finally, extinction is associated with damage to the temporo-parietal junction. Further, we describe key choices that must be made to parse the spatial and attentional syndromes that result from right hemisphere injury, including the investigation of both acute and chronic injury as well as the use of functional and structural modalities. PMID:21756924

  14. Multiwavelength metasurfaces through spatial multiplexing

    PubMed Central

    Arbabi, Ehsan; Arbabi, Amir; Kamali, Seyedeh Mahsa; Horie, Yu; Faraon, Andrei

    2016-01-01

    Metasurfaces are two-dimensional arrangements of optical scatterers rationally arranged to control optical wavefronts. Despite the significant advances made in wavefront engineering through metasurfaces, most of these devices are designed for and operate at a single wavelength. Here we show that spatial multiplexing schemes can be applied to increase the number of operation wavelengths. We use a high contrast dielectric transmittarray platform with amorphous silicon nano-posts to demonstrate polarization insensitive metasurface lenses with a numerical aperture of 0.46, that focus light at 915 and 1550 nm to the same focal distance. We investigate two different methods, one based on large scale segmentation and one on meta-atom interleaving, and compare their performances. An important feature of this method is its simple generalization to adding more wavelengths or new functionalities to a device. Therefore, it provides a relatively straightforward method for achieving multi-functional and multiwavelength metasurface devices. PMID:27597568

  15. Nonuniform spatially adaptive wavelet packets

    NASA Astrophysics Data System (ADS)

    Carre, Philippe; Fernandez-Maloigne, Christine

    2000-12-01

    In this paper, we propose a new decomposition scheme for spatially adaptive wavelet packets. Contrary to the double tree algorithm, our method is non-uniform and shift- invariant in the time and frequency domains, and is minimal for an information cost function. We prose some-restrictions to our algorithm to reduce the complexity and permitting us to provide some time-frequency partitions of the signal in agreement with its structure. This new 'totally' non-uniform transform, more adapted than Malvar, Packets or dyadic double-tree decomposition, allows the study of all possible time-frequency partitions with the only restriction that the blocks are rectangular. It permits one to obtain a satisfying Time-Frequency representation, and is applied for the study of EEG signals.

  16. Visualizing Spatially Varying Distribution Data

    NASA Technical Reports Server (NTRS)

    Kao, David; Luo, Alison; Dungan, Jennifer L.; Pang, Alex; Biegel, Bryan A. (Technical Monitor)

    2002-01-01

    Box plot is a compact representation that encodes the minimum, maximum, mean, median, and quarters information of a distribution. In practice, a single box plot is drawn for each variable of interest. With the advent of more accessible computing power, we are now facing the problem of visual icing data where there is a distribution at each 2D spatial location. Simply extending the box plot technique to distributions over 2D domain is not straightforward. One challenge is reducing the visual clutter if a box plot is drawn over each grid location in the 2D domain. This paper presents and discusses two general approaches, using parametric statistics and shape descriptors, to present 2D distribution data sets. Both approaches provide additional insights compared to the traditional box plot technique

  17. Spatial characterization of BNCT beams.

    PubMed

    Marek, M; Viererbl, L

    2004-11-01

    The space distribution of the epithermal neutron flux was determined for the epithermal neutron beams of several NCT facilities in USA (FCB at MIT), Europe (HFR at JRC, Petten; FiR at VTT, Espoo; LVR-15 at NRI, Rez) and Japan (JRR-4 at JAERI, Tokai). Using p-n diodes with (6)Li radiator and the set of Bonner sphere spectrometer (BSS) the beams were quantified in-air. Axial beam profiles along the beam axes and the radial distributions at two distances from the beam aperture were measured. Except for the well-collimated HFR beam, the spatial characteristics of the other studied beams were found generally similar, which results from their similar designs.

  18. Marine spatial planning in Cyprus

    NASA Astrophysics Data System (ADS)

    Hadjimitsis, Diofantos; Agapiou, Athos; Mettas, Christodoulos; Themistocleous, Kyriacos; Evagorou, Evagoras; Cuca, Branka; Papoutsa, Christiana; Nisantzi, Argyro; Mamouri, Rodanthi-Elisavet; Soulis, George; Xagoraris, Zafiris; Lysandrou, Vasiliki; Aliouris, Kyriacos; Ioannou, Nicolas; Pavlogeorgatos, Gerasimos

    2015-06-01

    Marine Spatial Planning (MSP), which is in concept similar to land-use planning, is a public process by which the relevant Member State's authorities analyse and organise human activities in marine areas to achieve ecological, economic and social objectives. MSP aims to promote sustainable growth of maritime economies, sustainable development of marine areas and sustainable use of marine resources. This paper highlights the importance of MSP and provides basic outcomes of the main European marine development. The already successful MSP plans can provide useful feedback and guidelines for other countries that are in the process of implementation of an integrated MSP, such as Cyprus. This paper presents part of the MSP project, of which 80% funded by the European Regional Development Fund (ERDF) and 20% from national contribution. An overview of the project is presented, including data acquisition, methodology and preliminary results for the implementation of MSP in Cyprus.

  19. Spatial light interference tomography (SLIT)

    PubMed Central

    Wang, Zhuo; Marks, Daniel L.; Carney, Paul Scott; Millet, Larry J.; Gillette, Martha U.; Mihi, Agustin; Braun, Paul V.; Shen, Zhen; Prasanth, Supriya G.; Popescu, Gabriel

    2011-01-01

    We present spatial light interference tomography (SLIT), a label-free method for 3D imaging of transparent structures such as live cells. SLIT uses the principle of interferometric imaging with broadband fields and combines the optical gating due to the micron-scale coherence length with that of the high numerical aperture objective lens. Measuring the phase shift map associated with the object as it is translated through focus provides full information about the 3D distribution associated with the refractive index. Using a reconstruction algorithm based on the Born approximation, we show that the sample structure may be recovered via a 3D, complex field deconvolution. We illustrate the method with reconstructed tomographic refractive index distributions of microspheres, photonic crystals, and unstained living cells. PMID:21996999

  20. Natural Resources and Spatial Spillovers

    NASA Astrophysics Data System (ADS)

    Batbold, Dulguun

    Regions going through a natural resource boom tend to have higher average incomes and employment relative to the rest of the country. For policy analysis, a question that often needs to be answered is to what extent the economic growth in the extraction region spills over to neighboring areas. This thesis develops a detailed methodology for analyzing the economic effects of geographically localized shocks within the framework of a parsimonious spatial general equilibrium model, including various methods for estimating key parameters. This model-based approach is being offered as a complementary tool for applied researchers conducting economic impact analysis. Existing empirical methods such as input-output analysis or difference-in-difference estimation techniques are often not optimal for analyzing spatially correlated data, and this model-based methodology can be used to overcome their limitations. Another important advantage of this methodology is that it is computationally tractable and has a relatively low data requirement, which can make a particularly big difference in studying developing countries where data quality and availability can often be an insurmountable challenge. Following the exposition of the methodology, this thesis presents two separate applications, one involving a developed nation and the other a developing one. In the first case, the methodology is applied to analyze the economic impact of the shale energy boom that's been occurring in and around Bakken counties in western North Dakota and eastern Montana over the past decade. In the second case, the methodology is used to analyze the economic impact of the Oyu Tolgoi copper-gold mining project in the Southern Gobi region of Mongolia. A common conclusion that is drawn from the two applications mentioned above is that economic booms fueled by natural resource extracting industries are largely local and have limited spillover effects on neighboring regions.

  1. Spatial Uncertainty Analysis of Ecological Models

    SciTech Connect

    Jager, H.I.; Ashwood, T.L.; Jackson, B.L.; King, A.W.

    2000-09-02

    The authors evaluated the sensitivity of a habitat model and a source-sink population model to spatial uncertainty in landscapes with different statistical properties and for hypothetical species with different habitat requirements. Sequential indicator simulation generated alternative landscapes from a source map. Their results showed that spatial uncertainty was highest for landscapes in which suitable habitat was rare and spatially uncorrelated. Although, they were able to exert some control over the degree of spatial uncertainty by varying the sampling density drawn from the source map, intrinsic spatial properties (i.e., average frequency and degree of spatial autocorrelation) played a dominant role in determining variation among realized maps. To evaluate the ecological significance of landscape variation, they compared the variation in predictions from a simple habitat model to variation among landscapes for three species types. Spatial uncertainty in predictions of the amount of source habitat depended on both the spatial life history characteristics of the species and the statistical attributes of the synthetic landscapes. Species differences were greatest when the landscape contained a high proportion of suitable habitat. The predicted amount of source habitat was greater for edge-dependent (interior) species in landscapes with spatially uncorrelated(correlated) suitable habitat. A source-sink model demonstrated that, although variation among landscapes resulted in relatively little variation in overall population growth rate, this spatial uncertainty was sufficient in some situations, to produce qualitatively different predictions about population viability (i.e., population decline vs. increase).

  2. Ventral striatal plasticity and spatial memory.

    PubMed

    Ferretti, Valentina; Roullet, Pascal; Sargolini, Francesca; Rinaldi, Arianna; Perri, Valentina; Del Fabbro, Martina; Costantini, Vivian J A; Annese, Valentina; Scesa, Gianluigi; De Stefano, Maria Egle; Oliverio, Alberto; Mele, Andrea

    2010-04-27

    Spatial memory formation is a dynamic process requiring a series of cellular and molecular steps, such as gene expression and protein translation, leading to morphological changes that have been envisaged as the structural bases for the engram. Despite the role suggested for medial temporal lobe plasticity in spatial memory, recent behavioral observations implicate specific components of the striatal complex in spatial information processing. However, the potential occurrence of neural plasticity within this structure after spatial learning has never been investigated. In this study we demonstrate that blockade of cAMP response element binding protein-induced transcription or inhibition of protein synthesis or extracellular proteolytic activity in the ventral striatum impairs long-term spatial memory. These findings demonstrate that, in the ventral striatum, similarly to what happens in the hippocampus, several key molecular events crucial for the expression of neural plasticity are required in the early stages of spatial memory formation.

  3. Ventral striatal plasticity and spatial memory

    PubMed Central

    Ferretti, Valentina; Roullet, Pascal; Sargolini, Francesca; Rinaldi, Arianna; Perri, Valentina; Del Fabbro, Martina; Costantini, Vivian J. A.; Annese, Valentina; Scesa, Gianluigi; De Stefano, Maria Egle; Oliverio, Alberto; Mele, Andrea

    2010-01-01

    Spatial memory formation is a dynamic process requiring a series of cellular and molecular steps, such as gene expression and protein translation, leading to morphological changes that have been envisaged as the structural bases for the engram. Despite the role suggested for medial temporal lobe plasticity in spatial memory, recent behavioral observations implicate specific components of the striatal complex in spatial information processing. However, the potential occurrence of neural plasticity within this structure after spatial learning has never been investigated. In this study we demonstrate that blockade of cAMP response element binding protein–induced transcription or inhibition of protein synthesis or extracellular proteolytic activity in the ventral striatum impairs long-term spatial memory. These findings demonstrate that, in the ventral striatum, similarly to what happens in the hippocampus, several key molecular events crucial for the expression of neural plasticity are required in the early stages of spatial memory formation. PMID:20351272

  4. Extraversion-introversion and spatial intelligence.

    PubMed

    Dunn, A; Eliot, J

    1993-08-01

    The purpose of this study was to assess whether extraversion-introversion is related to spatial intelligence. First-year psychology students (58 men, 108 women) in an open-admission community college responded to a battery of black and white and color spatial ability tests, and the Eysenck Personality Inventory. As hypothesized, a small but significant relationship was found between scores on extraversion and on the SEK Test (colored spatial test). Gender differences in performance on the spatial tests favored males. Scores on three of the Spatial Dimensionality Tests correlated significantly with those on the SEK Test. Recommendations include investigating the effect of a variety of spatial problems in combination with other personality variables.

  5. Four-dimensional spatial reasoning in humans.

    PubMed

    Aflalo, T N; Graziano, M S A

    2008-10-01

    Human subjects practiced navigation in a virtual, computer-generated maze that contained 4 spatial dimensions rather than the usual 3. The subjects were able to learn the spatial geometry of the 4-dimensional maze as measured by their ability to perform path integration, a standard test of spatial ability. They were able to travel down a winding corridor to its end and then point back accurately toward the occluded origin. One interpretation is that the brain substrate for spatial navigation is not a built-in map of the 3-dimensional world. Instead it may be better described as a set of general rules for manipulating spatial information that can be applied with practice to a diversity of spatial frameworks.

  6. Spatial data grid based on CDN

    NASA Astrophysics Data System (ADS)

    Hu, XiaoGuang; Zhu, Xinyan; Li, Deren

    2008-12-01

    This paper firstly introduces the spatial data grid and the CDN (Content Delivery Network) technology. And then it depicts the significance of integrating grid with CDN. On this basis, this paper proposes a method of constructing the spatial data grid system by using CDN to support the massive spatial data online service. Finally, the simulation results by OPNET show that the programme do can improve the system performance, and reduce response time in a greater extent.

  7. Auditory spatial processing in Alzheimer's disease.

    PubMed

    Golden, Hannah L; Nicholas, Jennifer M; Yong, Keir X X; Downey, Laura E; Schott, Jonathan M; Mummery, Catherine J; Crutch, Sebastian J; Warren, Jason D

    2015-01-01

    The location and motion of sounds in space are important cues for encoding the auditory world. Spatial processing is a core component of auditory scene analysis, a cognitively demanding function that is vulnerable in Alzheimer's disease. Here we designed a novel neuropsychological battery based on a virtual space paradigm to assess auditory spatial processing in patient cohorts with clinically typical Alzheimer's disease (n = 20) and its major variant syndrome, posterior cortical atrophy (n = 12) in relation to healthy older controls (n = 26). We assessed three dimensions of auditory spatial function: externalized versus non-externalized sound discrimination, moving versus stationary sound discrimination and stationary auditory spatial position discrimination, together with non-spatial auditory and visual spatial control tasks. Neuroanatomical correlates of auditory spatial processing were assessed using voxel-based morphometry. Relative to healthy older controls, both patient groups exhibited impairments in detection of auditory motion, and stationary sound position discrimination. The posterior cortical atrophy group showed greater impairment for auditory motion processing and the processing of a non-spatial control complex auditory property (timbre) than the typical Alzheimer's disease group. Voxel-based morphometry in the patient cohort revealed grey matter correlates of auditory motion detection and spatial position discrimination in right inferior parietal cortex and precuneus, respectively. These findings delineate auditory spatial processing deficits in typical and posterior Alzheimer's disease phenotypes that are related to posterior cortical regions involved in both syndromic variants and modulated by the syndromic profile of brain degeneration. Auditory spatial deficits contribute to impaired spatial awareness in Alzheimer's disease and may constitute a novel perceptual model for probing brain network disintegration across the Alzheimer's disease

  8. Spatial-Operator Algebra For Robotic Manipulators

    NASA Technical Reports Server (NTRS)

    Rodriguez, Guillermo; Kreutz, Kenneth K.; Milman, Mark H.

    1991-01-01

    Report discusses spatial-operator algebra developed in recent studies of mathematical modeling, control, and design of trajectories of robotic manipulators. Provides succinct representation of mathematically complicated interactions among multiple joints and links of manipulator, thereby relieving analyst of most of tedium of detailed algebraic manipulations. Presents analytical formulation of spatial-operator algebra, describes some specific applications, summarizes current research, and discusses implementation of spatial-operator algebra in the Ada programming language.

  9. Spatial coherence of random laser emission

    NASA Astrophysics Data System (ADS)

    Redding, B.; Choma, M. A.; Cao, H.

    2011-09-01

    Lasing action in disordered media has been studied extensively in recent years and many of its properties are well understood. However, few studies have considered the spatial coherence in these systems, despite initial observations indicating that random lasers exhibit much lower spatial coherence than conventional lasers. We performed a systematic, experimental investigation of the spatial coherence of random laser emission as a function of the scattering mean free path and the excitation volume. Lasing was achieved under optical excitation and spatial coherence was characterized by imaging the emission spot onto a Young's double slit and collecting the interference fringes in the far field. We observed dramatic differences in the spatial coherence within our parameter space. Specifically, we found that samples with a shorter mean free path relative to the excitation volume exhibited reduced spatial coherence. We provide a qualitative explanation of our experimental observations in terms of the number of excited modes and their spatial orientation. This work provides a means to realize intense, spatially incoherent laser emission for applications in which speckle or spatial cross talk limits performance.

  10. NASA World Wind: Infrastructure for Spatial Data

    NASA Technical Reports Server (NTRS)

    Hogan, Patrick

    2011-01-01

    The world has great need for analysis of Earth observation data, be it climate change, carbon monitoring, disaster response, national defense or simply local resource management. To best provide for spatial and time-dependent information analysis, the world benefits from an open standards and open source infrastructure for spatial data. In the spirit of NASA's motto "for the benefit of all" NASA invites the world community to collaboratively advance this core technology. The World Wind infrastructure for spatial data both unites and challenges the world for innovative solutions analyzing spatial data while also allowing absolute command and control over any respective information exchange medium.

  11. An Empirical Bayes Approach to Spatial Analysis

    NASA Technical Reports Server (NTRS)

    Morris, C. N.; Kostal, H.

    1983-01-01

    Multi-channel LANDSAT data are collected in several passes over agricultural areas during the growing season. How empirical Bayes modeling can be used to develop crop identification and discrimination techniques that account for spatial correlation in such data is considered. The approach models the unobservable parameters and the data separately, hoping to take advantage of the fact that the bulk of spatial correlation lies in the parameter process. The problem is then framed in terms of estimating posterior probabilities of crop types for each spatial area. Some empirical Bayes spatial estimation methods are used to estimate the logits of these probabilities.

  12. A neuromorphic model of spatial lookahead planning.

    PubMed

    Ivey, Richard; Bullock, Daniel; Grossberg, Stephen

    2011-04-01

    In order to create spatial plans in a complex and changing world, organisms need to rapidly adapt to novel configurations of obstacles that impede simple routes to goal acquisition. Some animals can mentally create successful multistep spatial plans in new visuo-spatial layouts that preclude direct, one-segment routes to goal acquisition. Lookahead multistep plans can, moreover, be fully developed before an animal executes any step in the plan. What neural computations suffice to yield preparatory multistep lookahead plans during spatial cognition of an obstructed two-dimensional scene? To address this question, we introduce a novel neuromorphic system for spatial lookahead planning in which a feasible sequence of actions is prepared before movement begins. The proposed system combines neurobiologically plausible mechanisms of recurrent shunting competitive networks, visuo-spatial diffusion, and inhibition-of-return. These processes iteratively prepare a multistep trajectory to the desired goal state in the presence of obstacles. The planned trajectory can be stored using a primacy gradient in a sequential working memory and enacted by a competitive queuing process. The proposed planning system is compared with prior planning models. Simulation results demonstrate system robustness to environmental variations. Notably, the model copes with many configurations of obstacles that lead other visuo-spatial planning models into selecting undesirable or infeasible routes. Our proposal is inspired by mechanisms of spatial attention and planning in primates. Accordingly, our simulation results are compared with neurophysiological and behavioral findings from relevant studies of spatial lookahead behavior.

  13. Bioconvection in spatially extended domains

    NASA Astrophysics Data System (ADS)

    Karimi, A.; Paul, M. R.

    2013-05-01

    We numerically explore gyrotactic bioconvection in large spatially extended domains of finite depth using parameter values from available experiments with the unicellular alga Chlamydomonas nivalis. We numerically integrate the three-dimensional, time-dependent continuum model of Pedley [J. Fluid Mech.10.1017/S0022112088002393 195, 223 (1988)] using a high-order, parallel, spectral-element approach. We explore the long-time nonlinear patterns and dynamics found for layers with an aspect ratio of 10 over a range of Rayleigh numbers. Our results yield the pattern wavelength and pattern dynamics which we compare with available theory and experimental measurement. There is good agreement for the pattern wavelength at short times between numerics, experiment, and a linear stability analysis. At long times we find that the general sequence of patterns given by the nonlinear evolution of the governing equations correspond qualitatively to what has been described experimentally. However, at long times the patterns in numerics grow to larger wavelengths, in contrast to what is observed in experiment where the wavelength is found to decrease with time.

  14. Spatial layout affects speed discrimination

    NASA Technical Reports Server (NTRS)

    Verghese, P.; Stone, L. S.

    1997-01-01

    We address a surprising result in a previous study of speed discrimination with multiple moving gratings: discrimination thresholds decreased when the number of stimuli was increased, but remained unchanged when the area of a single stimulus was increased [Verghese & Stone (1995). Vision Research, 35, 2811-2823]. In this study, we manipulated the spatial- and phase relationship between multiple grating patches to determine their effect on speed discrimination thresholds. In a fusion experiment, we merged multiple stimulus patches, in stages, into a single patch. Thresholds increased as the patches were brought closer and their phase relationship was adjusted to be consistent with a single patch. Thresholds increased further still as these patches were fused into a single patch. In a fission experiment, we divided a single large patch into multiple patches by superimposing a cross with luminance equal to that of the background. Thresholds decreased as the large patch was divided into quadrants and decreased further as the quadrants were maximally separated. However, when the cross luminance was darker than the background, it was perceived as an occluder and thresholds, on average, were unchanged from that for the single large patch. A control experiment shows that the observed trend in discrimination thresholds is not due to the differences in perceived speed of the stimuli. These results suggest that the parsing of the visual image into entities affects the combination of speed information across space, and that each discrete entity effectively provides a single independent estimate of speed.

  15. Semantics of directly manipulating spatializations.

    PubMed

    Hu, Xinran; Bradel, Lauren; Maiti, Dipayan; House, Leanna; North, Chris; Leman, Scotland

    2013-12-01

    When high-dimensional data is visualized in a 2D plane by using parametric projection algorithms, users may wish to manipulate the layout of the data points to better reflect their domain knowledge or to explore alternative structures. However, few users are well-versed in the algorithms behind the visualizations, making parameter tweaking more of a guessing game than a series of decisive interactions. Translating user interactions into algorithmic input is a key component of Visual to Parametric Interaction (V2PI) [13]. Instead of adjusting parameters, users directly move data points on the screen, which then updates the underlying statistical model. However, we have found that some data points that are not moved by the user are just as important in the interactions as the data points that are moved. Users frequently move some data points with respect to some other 'unmoved' data points that they consider as spatially contextual. However, in current V2PI interactions, these points are not explicitly identified when directly manipulating the moved points. We design a richer set of interactions that makes this context more explicit, and a new algorithm and sophisticated weighting scheme that incorporates the importance of these unmoved data points into V2PI.

  16. Path planning under spatial uncertainty.

    PubMed

    Wiener, Jan M; Lafon, Matthieu; Berthoz, Alain

    2008-04-01

    In this article, we present experiments studying path planning under spatial uncertainties. In the main experiment, the participants' task was to navigate the shortest possible path to find an object hidden in one of four places and to bring it to the final destination. The probability of finding the object (probability matrix) was different for each of the four places and varied between conditions. Givensuch uncertainties about the object's location, planning a single path is not sufficient. Participants had to generate multiple consecutive plans (metaplans)--for example: If the object is found in A, proceed to the destination; if the object is not found, proceed to B; and so on. The optimal solution depends on the specific probability matrix. In each condition, participants learned a different probability matrix and were then asked to report the optimal metaplan. Results demonstrate effective integration of the probabilistic information about the object's location during planning. We present a hierarchical planning scheme that could account for participants' behavior, as well as for systematic errors and differences between conditions.

  17. Spatial processing in color reproduction

    NASA Astrophysics Data System (ADS)

    Liu, Li; Yang, Yongyi; Stark, Henry

    2005-08-01

    We consider the reproduction of color subject to material and neighborhood constraints. By 'material constraints,' we mean any constraints that are applied to the amount of ink, lights, voltages, and currents that are used in the generation of color. In the first instance we consider the problem of reproducing a target color constrained by maximum additive color signals, such as in the phosphorescence process in a cathode ray tube. In the second instance we consider the more difficult problem of reproducing color subject to constraints on the maximum primary color variations in a (spatial) neighborhood. We introduce the idea of adjacent color variance (ACV) and then attempt to reproduce colors subject to an upper bound on the ACV. An algorithm that is suitable for this task is the method of vector space projections (VSP). In order to use VSP for constrained color reproduction, we use a novel approach to linearize nonlinear CIE-Lab space constraints. Experimental results are furnished that demonstrate that using the ACV as a bound helps to reduce reproduction artifacts in a color image.

  18. The Joint Role of Spatial Ability and Imagery Strategy in Sustaining the Learning of Spatial Descriptions under Spatial Interference

    ERIC Educational Resources Information Center

    Meneghetti, Chiara; De Beni, Rossana; Gyselinck, Valerie; Pazzaglia, Francesca

    2013-01-01

    The present study investigates the joint role of spatial ability, imagery strategy and visuospatial working memory (VSWM) in spatial text processing. A set of 180 participants, half of them trained on the use of imagery strategy (training vs no-training groups), was further divided according to participants' high or low mental rotation ability…

  19. Tactile feedback improves auditory spatial localization.

    PubMed

    Gori, Monica; Vercillo, Tiziana; Sandini, Giulio; Burr, David

    2014-01-01

    Our recent studies suggest that congenitally blind adults have severely impaired thresholds in an auditory spatial bisection task, pointing to the importance of vision in constructing complex auditory spatial maps (Gori et al., 2014). To explore strategies that may improve the auditory spatial sense in visually impaired people, we investigated the impact of tactile feedback on spatial auditory localization in 48 blindfolded sighted subjects. We measured auditory spatial bisection thresholds before and after training, either with tactile feedback, verbal feedback, or no feedback. Audio thresholds were first measured with a spatial bisection task: subjects judged whether the second sound of a three sound sequence was spatially closer to the first or the third sound. The tactile feedback group underwent two audio-tactile feedback sessions of 100 trials, where each auditory trial was followed by the same spatial sequence played on the subject's forearm; auditory spatial bisection thresholds were evaluated after each session. In the verbal feedback condition, the positions of the sounds were verbally reported to the subject after each feedback trial. The no feedback group did the same sequence of trials, with no feedback. Performance improved significantly only after audio-tactile feedback. The results suggest that direct tactile feedback interacts with the auditory spatial localization system, possibly by a process of cross-sensory recalibration. Control tests with the subject rotated suggested that this effect occurs only when the tactile and acoustic sequences are spatially congruent. Our results suggest that the tactile system can be used to recalibrate the auditory sense of space. These results encourage the possibility of designing rehabilitation programs to help blind persons establish a robust auditory sense of space, through training with the tactile modality.

  20. Loss of form vision impairs spatial imagery

    PubMed Central

    Occelli, Valeria; Lin, Jonathan B.; Lacey, Simon; Sathian, K.

    2014-01-01

    Previous studies have reported inconsistent results when comparing spatial imagery performance in the blind and the sighted, with some, but not all, studies demonstrating deficits in the blind. Here, we investigated the effect of visual status and individual preferences (“cognitive style”) on performance of a spatial imagery task. Participants with blindness resulting in the loss of form vision at or after age 6, and age- and gender-matched sighted participants, performed a spatial imagery task requiring memorization of a 4 × 4 lettered matrix and subsequent mental construction of shapes within the matrix from four-letter auditory cues. They also completed the Santa Barbara Sense of Direction Scale (SBSoDS) and a self-evaluation of cognitive style. The sighted participants also completed the Object-Spatial Imagery and Verbal Questionnaire (OSIVQ). Visual status affected performance on the spatial imagery task: the blind performed significantly worse than the sighted, independently of the age at which form vision was completely lost. Visual status did not affect the distribution of preferences based on self-reported cognitive style. Across all participants, self-reported verbalizer scores were significantly negatively correlated with accuracy on the spatial imagery task. There was a positive correlation between the SBSoDS score and accuracy on the spatial imagery task, across all participants, indicating that a better sense of direction is related to a more proficient spatial representation and that the imagery task indexes ecologically relevant spatial abilities. Moreover, the older the participants were, the worse their performance was, indicating a detrimental effect of age on spatial imagery performance. Thus, spatial skills represent an important target for rehabilitative approaches to visual impairment, and individual differences, which can modulate performance, should be taken into account in such approaches. PMID:24678294

  1. Spatial Processing in Infancy Predicts Both Spatial and Mathematical Aptitude in Childhood.

    PubMed

    Lauer, Jillian E; Lourenco, Stella F

    2016-10-01

    Despite considerable interest in the role of spatial intelligence in science, technology, engineering, and mathematics (STEM) achievement, little is known about the ontogenetic origins of individual differences in spatial aptitude or their relation to later accomplishments in STEM disciplines. The current study provides evidence that spatial processes present in infancy predict interindividual variation in both spatial and mathematical competence later in development. Using a longitudinal design, we found that children's performance on a brief visuospatial change-detection task administered between 6 and 13 months of age was related to their spatial aptitude (i.e., mental-transformation skill) and mastery of symbolic-math concepts at 4 years of age, even when we controlled for general cognitive abilities and spatial memory. These results suggest that nascent spatial processes present in the first year of life not only act as precursors to later spatial intelligence but also predict math achievement during childhood.

  2. Plasticity of human spatial cognition: spatial language and cognition covary across cultures.

    PubMed

    Haun, Daniel B M; Rapold, Christian J; Janzen, Gabriele; Levinson, Stephen C

    2011-04-01

    The present paper explores cross-cultural variation in spatial cognition by comparing spatial reconstruction tasks by Dutch and Namibian elementary school children. These two communities differ in the way they predominantly express spatial relations in language. Four experiments investigate cognitive strategy preferences across different levels of task-complexity and instruction. Data show a correlation between dominant linguistic spatial frames of reference and performance patterns in non-linguistic spatial memory tasks. This correlation is shown to be stable across an increase of complexity in the spatial array. When instructed to use their respective non-habitual cognitive strategy, participants were not easily able to switch between strategies and their attempts to do so impaired their performance. These results indicate a difference not only in preference but also in competence and suggest that spatial language and non-linguistic preferences and competences in spatial cognition are systematically aligned across human populations.

  3. A spatially explicit risk approach to support marine spatial planning in the German EEZ.

    PubMed

    Gimpel, Antje; Stelzenmüller, Vanessa; Cormier, Roland; Floeter, Jens; Temming, Axel

    2013-05-01

    An ecosystem approach to marine spatial planning (MSP) promotes sustainable development by organizing human activities in a geo-spatial and temporal context. (1) This study develops and tests a spatially explicit risk assessment to support MSP. Using the German exclusive economic zone (EEZ) of the North Sea as a case study area, current and future spatial management scenarios are assessed. (2) Different tools are linked in order to carry out a comprehensive spatial risk assessment of current and future spatial management scenarios for ecologic and economic ecosystem components, i.e. Pleuronectes platessa nursery grounds. With the identification of key inputs and outputs the suitability of each tool is tested. (3) Here, the procedure as well as the main findings of the spatially explicit risk approach are summarised to demonstrate the applicability of the framework and the need for an ecosystem approach to risk management techniques using geo-spatial tools.

  4. Hungry for Early Spatial and Algebraic Reasoning

    ERIC Educational Resources Information Center

    Cross, Dionne I.; Adefope, Olufunke; Lee, Mi Yeon; Perez, Arnulfo

    2012-01-01

    Tasks that develop spatial and algebraic reasoning are crucial for learning and applying advanced mathematical ideas. In this article, the authors describe how two early childhood teachers used stories as the basis for a unit that supports spatial reasoning in kindergartners and first graders. Having mathematical experiences that go beyond…

  5. A Computational Model of Spatial Visualization Capacity

    ERIC Educational Resources Information Center

    Lyon, Don R.; Gunzelmann, Glenn; Gluck, Kevin A.

    2008-01-01

    Visualizing spatial material is a cornerstone of human problem solving, but human visualization capacity is sharply limited. To investigate the sources of this limit, we developed a new task to measure visualization accuracy for verbally-described spatial paths (similar to street directions), and implemented a computational process model to…

  6. Spatial Ability Learning through Educational Robotics

    ERIC Educational Resources Information Center

    Julià, Carme; Antolí, Juan Òscar

    2016-01-01

    Several authors insist on the importance of students' acquisition of spatial abilities and visualization in order to have academic success in areas such as science, technology or engineering. This paper proposes to discuss and analyse the use of educational robotics to develop spatial abilities in 12 year old students. First of all, a course to…

  7. Misprojection of Landmarks onto the Spatial Map

    ERIC Educational Resources Information Center

    Toraldo, Alessio; Reverberi, Carlo

    2004-01-01

    It has been suggested that neglect patients misrepresent the metric spatial relations along the horizontal axis (anisometry). The ''fabric'' of their internal spatial medium would be distorted in such a way that physically equal distances appear relatively shorter on the contralesional side (canonical anisometry). The case of GL, a 76-year-old…

  8. Spatial Ability through Engineering Graphics Education

    ERIC Educational Resources Information Center

    Marunic, Gordana; Glazar, Vladimir

    2013-01-01

    Spatial ability has been confirmed to be of particular importance for successful engineering graphics education and to be a component of human intelligence that can be improved through instruction and training. Consequently, the creation and communication by means of graphics demand careful development of spatial skills provided by the balanced…

  9. SPATIAL APPROACH TO PLANNING THE PHYSICAL ENVIRONMENT.

    ERIC Educational Resources Information Center

    BELLOMY, CLEON C.; CAUDILL, WILLIAM W.

    THE PURPOSE OF THIS REPORT DEFINES THE SPATIAL APPROACH TO PLANNING THE PHYSICAL ENVIRONMENT AND SUGGESTS A MORE NATURAL APPROACH TO A LESS RESTRICTED ARCHITECTURE. ONE OF THE TWO BASIC ARCHITECTURAL ELEMENTS IN THE SPATIAL CONCEPT IS THE HORIZONTAL SCREEN WHICH KEEPS THE SUN AND RAIN OFF, LETS IN LIGHT, KEEPS OUT SUN HEAT, RETAINS ROOM HEAT, AND…

  10. Two-wavelength spatial-heterodyne holography

    DOEpatents

    Hanson, Gregory R.; Bingham, Philip R.; Simpson, John T.; Karnowski, Thomas P.; Voelkl, Edgar

    2007-12-25

    Systems and methods are described for obtaining two-wavelength differential-phase holograms. A method includes determining a difference between a filtered analyzed recorded first spatially heterodyne hologram phase and a filtered analyzed recorded second spatially-heterodyned hologram phase.

  11. Spatial Language, Visual Attention, and Perceptual Simulation

    ERIC Educational Resources Information Center

    Coventry, Kenny R.; Lynott, Dermot; Cangelosi, Angelo; Monrouxe, Lynn; Joyce, Dan; Richardson, Daniel C.

    2010-01-01

    Spatial language descriptions, such as "The bottle is over the glass", direct the attention of the hearer to particular aspects of the visual world. This paper asks how they do so, and what brain mechanisms underlie this process. In two experiments employing behavioural and eye tracking methodologies we examined the effects of spatial language on…

  12. SPATIALLY-BALANCED SAMPLING OF NATURAL RESOURCES

    EPA Science Inventory

    The spatial distribution of a natural resource is an important consideration in designing an efficient survey or monitoring program for the resource. Generally, sample sites that are spatially-balanced, that is, more or less evenly dispersed over the extent of the resource, will ...

  13. Improving Student Understanding of Spatial Ecology Statistics

    ERIC Educational Resources Information Center

    Hopkins, Robert, II; Alberts, Halley

    2015-01-01

    This activity is designed as a primer to teaching population dispersion analysis. The aim is to help improve students' spatial thinking and their understanding of how spatial statistic equations work. Students use simulated data to develop their own statistic and apply that equation to experimental behavioral data for Gambusia affinis (western…

  14. Learning To Make Music Enhances Spatial Reasoning.

    ERIC Educational Resources Information Center

    Hetland, Lois

    2000-01-01

    Examines whether active instruction in music enhances preschool and elementary school student performance on spatial tasks. Reports that music enhances the spatial-temporal performance of children during and up to two years following the instruction and that the effect is moderate and consistent. Includes references. (CMK)

  15. Neurodynamics With Spatial Self-Organization

    NASA Technical Reports Server (NTRS)

    Zak, Michail A.

    1993-01-01

    Report presents theoretical study of dynamics of neural network organizing own response in both phase space and in position space. Postulates several mathematical models of dynamics including spatial derivatives representing local interconnections among neurons. Shows how neural responses propagate via these interconnections and how spatial pattern of neural responses formed in homogeneous biological neural network.

  16. Spatial Performance, Cognitive Representation, and Cerebral Processes

    DTIC Science & Technology

    1984-07-01

    auditory- visual perception and visual proprioception in human development. In R. D. Walk & H. L. Pick, Jr. (Ed.). Intersensory perception and sensory...Spatial ability Sensory interaction Analog and prepositional representation Visual and auditory...systems is associated with spatial ability, visual , auditory, and bimodal brain event-related potentials were recorded from 50 right-handed

  17. Bone remodeling as a spatial evolutionary game.

    PubMed

    Ryser, Marc D; Murgas, Kevin A

    2017-04-07

    Bone remodeling is a complex process involving cell-cell interactions, biochemical signaling and mechanical stimuli. Early models of the biological aspects of remodeling were non-spatial and focused on the local dynamics at a fixed location in the bone. Several spatial extensions of these models have been proposed, but they generally suffer from two limitations: first, they are not amenable to analysis and are computationally expensive, and second, they neglect the role played by bone-embedded osteocytes. To address these issues, we developed a novel model of spatial remodeling based on the principles of evolutionary game theory. The analytically tractable framework describes the spatial interactions between zones of bone resorption, bone formation and quiescent bone, and explicitly accounts for regulation of remodeling by bone-embedded, mechanotransducing osteocytes. Using tools from the theory of interacting particle systems we systematically classified the different dynamic regimes of the spatial model and identified regions of parameter space that allow for global coexistence of resorption, formation and quiescence, as observed in physiological remodeling. In coexistence scenarios, three-dimensional simulations revealed the emergence of sponge-like bone clusters. Comparison between spatial and non-spatial dynamics revealed substantial differences and suggested a stabilizing role of space. Our findings emphasize the importance of accounting for spatial structure and bone-embedded osteocytes when modeling the process of bone remodeling. Thanks to the lattice-based framework, the proposed model can easily be coupled to a mechanical model of bone loading.

  18. Spatial processing and visual backward masking.

    PubMed

    Herzog, Michael H

    2008-07-15

    Most theories of visual masking focus prima-rily on the temporal aspects of visual information processing, strongly neglecting spatial factors. In recent years, however, we have shown that this position is not tenable. Spatial aspects cannot be neglected in metacontrast, pattern and un-masking. Here, we review these results.

  19. Spatial processing and visual backward masking

    PubMed Central

    Herzog, Michael H.

    2008-01-01

    Most theories of visual masking focus prima-rily on the temporal aspects of visual information processing, strongly neglecting spatial factors. In recent years, however, we have shown that this position is not tenable. Spatial aspects cannot be neglected in metacontrast, pattern and un-masking. Here, we review these results. PMID:20517500

  20. Spatial and Social Networks in Organizational Innovation

    ERIC Educational Resources Information Center

    Wineman, Jean D.; Kabo, Felichism W.; Davis, Gerald F.

    2009-01-01

    Research on the enabling factors of innovation has focused on either the social component of organizations or on the spatial dimensions involved in the innovation process. But no one has examined the aggregate consequences of the link from spatial layout, to social networks, to innovation. This project enriches our understanding of how innovation…

  1. Spatially variant periodic structures in electromagnetics

    PubMed Central

    Rumpf, Raymond C.; Pazos, Javier J.; Digaum, Jennefir L.; Kuebler, Stephen M.

    2015-01-01

    Spatial transforms are a popular technique for designing periodic structures that are macroscopically inhomogeneous. The structures are often required to be anisotropic, provide a magnetic response, and to have extreme values for the constitutive parameters in Maxwell's equations. Metamaterials and photonic crystals are capable of providing these, although sometimes only approximately. The problem still remains about how to generate the geometry of the final lattice when it is functionally graded, or spatially varied. This paper describes a simple numerical technique to spatially vary any periodic structure while minimizing deformations to the unit cells that would weaken or destroy the electromagnetic properties. New developments in this algorithm are disclosed that increase efficiency, improve the quality of the lattices and provide the ability to design aplanatic metasurfaces. The ability to spatially vary a lattice in this manner enables new design paradigms that are not possible using spatial transforms, three of which are discussed here. First, spatially variant self-collimating photonic crystals are shown to flow unguided waves around very tight bends using ordinary materials with low refractive index. Second, multi-mode waveguides in spatially variant band gap materials are shown to guide waves around bends without mixing power between the modes. Third, spatially variant anisotropic materials are shown to sculpt the near-field around electric components. This can be used to improve electromagnetic compatibility between components in close proximity. PMID:26217058

  2. Spatial Memory in Rats after 25 Hours

    ERIC Educational Resources Information Center

    Crystal, Jonathon D.; Babb, Stephanie J.

    2008-01-01

    We investigated the time course of spatial-memory decay in rats using an eight-arm radial maze. It is well established that performance remains high with retention intervals as long as 4 h, but declines to chance with a 24-h retention interval (Beatty, W. W., & Shavalia, D. A. (1980b). Spatial memory in rats: time course of working memory and…

  3. Connecting Spatial Memories of Two Nested Spaces

    ERIC Educational Resources Information Center

    Zhang, Hui; Mou, Weimin; McNamara, Timothy P.; Wang, Lin

    2014-01-01

    Four experiments investigated the manner in which people use spatial reference directions to organize spatial memories of 2 conceptually nested layouts. Participants learned directions of 8 remote cities centered to Beijing or Edmonton, where the experiments occurred, using a map or using direct pointing. The map and the environment were aligned,…

  4. Spatial and temporal variation in evapotranspiration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Spatial and temporal variation in evapotranspiration occurs at multiple scales as the result of several different spatial and temporal patterns in precipitation, soil water holding capacity, cloudiness (available energy), types of crops, and residue and tillage management practices. We have often as...

  5. Voluntary attention increases perceived spatial frequency.

    PubMed

    Abrams, Jared; Barbot, Antoine; Carrasco, Marisa

    2010-08-01

    Voluntary covert attention selects relevant sensory information for prioritized processing. The behavioral and neural consequences of such selection have been extensively documented, but its phenomenology has received little empirical investigation. Involuntary attention increases perceived spatial frequency (Gobell & Carrasco, 2005), but involuntary attention can differ from voluntary attention in its effects on performance in tasks mediated by spatial resolution (Yeshurun, Montagna, & Carrasco, 2008). Therefore, we ask whether voluntary attention affects the subjective appearance of spatial frequency--a fundamental dimension of visual perception underlying spatial resolution. We used a demanding rapid serial visual presentation task to direct voluntary attention and measured perceived spatial frequency at the attended and unattended locations. Attention increased the perceived spatial frequency of suprathreshold stimuli and also improved performance on a concurrent orientation discrimination task. In the control experiment, we ruled out response bias as an alternative account by using a lengthened interstimulus interval, which allows observers to disengage attention from the cued location. In contrast to the main experiment, the observers showed neither increased perceived spatial frequency nor improved orientation discrimination at the attended location. Thus, this study establishes that voluntary attention increases perceived spatial frequency. This phenomenological consequence links behavioral and neurophysiological studies on the effects of attention.

  6. Why Do Spatial Abilities Predict Mathematical Performance?

    ERIC Educational Resources Information Center

    Tosto, Maria Grazia; Hanscombe, Ken B.; Haworth, Claire M. A.; Davis, Oliver S. P.; Petrill, Stephen A.; Dale, Philip S.; Malykh, Sergey; Plomin, Robert; Kovas, Yulia

    2014-01-01

    Spatial ability predicts performance in mathematics and eventual expertise in science, technology and engineering. Spatial skills have also been shown to rely on neuronal networks partially shared with mathematics. Understanding the nature of this association can inform educational practices and intervention for mathematical underperformance.…

  7. Spatial abstraction for autonomous robot navigation.

    PubMed

    Epstein, Susan L; Aroor, Anoop; Evanusa, Matthew; Sklar, Elizabeth I; Parsons, Simon

    2015-09-01

    Optimal navigation for a simulated robot relies on a detailed map and explicit path planning, an approach problematic for real-world robots that are subject to noise and error. This paper reports on autonomous robots that rely on local spatial perception, learning, and commonsense rationales instead. Despite realistic actuator error, learned spatial abstractions form a model that supports effective travel.

  8. Disturbances of spatial perception in children.

    PubMed

    Meerwaldt, J D; van Dongen, H R

    1988-12-01

    Spatial perception was tested in 12 children with a localized brain lesion by means of the rod orientation test, line orientation test and facial recognition test. Only children with a lesion of the right hemisphere showed a disturbance of spatial perception.

  9. Modeling Mental Spatial Reasoning about Cardinal Directions

    ERIC Educational Resources Information Center

    Schultheis, Holger; Bertel, Sven; Barkowsky, Thomas

    2014-01-01

    This article presents research into human mental spatial reasoning with orientation knowledge. In particular, we look at reasoning problems about cardinal directions that possess multiple valid solutions (i.e., are spatially underdetermined), at human preferences for some of these solutions, and at representational and procedural factors that lead…

  10. Object Orientation Affects Spatial Language Comprehension

    ERIC Educational Resources Information Center

    Burigo, Michele; Sacchi, Simona

    2013-01-01

    Typical spatial descriptions, such as "The car is in front of the house," describe the position of a located object (LO; e.g., the car) in space relative to a reference object (RO) whose location is known (e.g., the house). The orientation of the RO affects spatial language comprehension via the reference frame selection process.…

  11. Sociospatial Schooling Practices: A Spatial Capital Approach

    ERIC Educational Resources Information Center

    Barthon, Catherine; Monfroy, Brigitte

    2010-01-01

    This paper highlights the importance today of the spatial dimension within the analysis of parents' education strategies concerning their school choices at the secondary school level. This study is based on the 2 dimensions of the concept of spatial capital (Levy, 1994): position capital and situation capital. It explores sociospatial schooling…

  12. Dynamics of Adaptation in Spatially Heterogeneous Metapopulations

    PubMed Central

    Papaïx, Julien; David, Olivier; Lannou, Christian; Monod, Hervé

    2013-01-01

    The selection pressure experienced by organisms often varies across the species range. It is hence crucial to characterise the link between environmental spatial heterogeneity and the adaptive dynamics of species or populations. We address this issue by studying the phenotypic evolution of a spatial metapopulation using an adaptive dynamics approach. The singular strategy is found to be the mean of the optimal phenotypes in each habitat with larger weights for habitats present in large and well connected patches. The presence of spatial clusters of habitats in the metapopulation is found to facilitate specialisation and to increase both the level of adaptation and the evolutionary speed of the population when dispersal is limited. By showing that spatial structures are crucial in determining the specialisation level and the evolutionary speed of a population, our results give insight into the influence of spatial heterogeneity on the niche breadth of species. PMID:23424618

  13. Spatially dependent Kondo effect in Quantum Corrals

    NASA Astrophysics Data System (ADS)

    Rossi, Enrico; Morr, Dirk K.

    2007-03-01

    We study the Kondo screening of a single magnetic impurity placed inside a quantum corral consisting of non-magnetic impurities on the surface of a metallic host system. We show that the spatial structure of the corral's eigenmodes leads to a spatially dependent Kondo effect whose signatures are experimentally measurable spatial variations of the Kondo temperature, TK, and of the critical Kondo coupling, Jcr. Moreover we find that the screening of the magnetic impurity is accompanied by the formation of multiple Kondo resonances with characteristic spatial patterns that provide further experimental signatures of the spatially dependent Kondo effect. Our results demonstrate that quantum corrals provide new possibilities to manipulate and explore the Kondo effect.

  14. Spatial effects on hybrid electric vehicle adoption

    DOE PAGES

    Liu, Xiaoli; Roberts, Matthew C.; Sioshansi, Ramteen

    2017-03-08

    This paper examines spatial effects on hybrid-electric vehicle (HEV) adoption. This is in contrast to most existing analyses, which concentrate on analyzing socioeconomic factors and demographics. This paper uses a general spatial model to estimate the strength of ‘neighbor effects’ on HEV adoption—namely that each consumer’s HEV-adoption decision can be influenced by the HEV-adoption decisions of geographic neighbors. We use detailed census tract-level demographic data from the 2010 United States Census and the 2012 American Community Survey and vehicle registration data collected by the Ohio Bureau of Motor Vehicles. We find that HEV adoption exhibits significant spatial effects. We furthermore » conduct a time-series analysis and show that historical HEV adoption has a spatial effect on future adoption. Lastly, these results suggest that HEVs may appear in more dense clusters than models that do not consider spatial effects predict.« less

  15. Auditory spatial processing in the human cortex.

    PubMed

    Salminen, Nelli H; Tiitinen, Hannu; May, Patrick J C

    2012-12-01

    The auditory system codes spatial locations in a way that deviates from the spatial representations found in other modalities. This difference is especially striking in the cortex, where neurons form topographical maps of visual and tactile space but where auditory space is represented through a population rate code. In this hemifield code, sound source location is represented in the activity of two widely tuned opponent populations, one tuned to the right and the other to the left side of auditory space. Scientists are only beginning to uncover how this coding strategy adapts to various spatial processing demands. This review presents the current understanding of auditory spatial processing in the cortex. To this end, the authors consider how various implementations of the hemifield code may exist within the auditory cortex and how these may be modulated by the stimulation and task context. As a result, a coherent set of neural strategies for auditory spatial processing emerges.

  16. Interpreting spatial language in image captions.

    PubMed

    Hall, Mark M; Smart, Philip D; Jones, Christopher B

    2011-02-01

    The map as a tool for accessing data has become very popular in recent years, but a lot of data do not have the necessary spatial meta-data to allow for that. Some data such as photographs however have spatial information in their captions and if this could be extracted, then they could be made available via map-based interfaces. Towards this goal, we introduce a model and spatio-linguistic reasoner for interpreting the spatial information in image captions that is based upon quantitative data about spatial language use acquired directly from people. Spatial language is inherently vague, and both the model and reasoner have been designed to incorporate this vagueness at the quantitative level and not only qualitatively.

  17. Spatially explicit analyses unveil density dependence.

    PubMed Central

    Veldtman, Ruan; McGeoch, Melodie A.

    2004-01-01

    Density-dependent processes are fundamental in the understanding of species population dynamics. Whereas the benefits of considering the spatial dimension in population biology are widely acknowledged, the implications of doing so for the statistical detection of spatial density dependence have not been examined. The outcome of traditional tests may therefore differ from those that include ecologically relevant locational information on both the prey species and natural enemy. Here, we explicitly incorporate spatial information on individual counts when testing for density dependence between an insect herbivore and its parasitoids. The spatially explicit approach used identified significant density dependence more frequently and in different instances than traditional methods. The form of density dependence detected also differed between methods. These results demonstrate that the explicit consideration of patch location in density-dependence analyses is likely to significantly alter current understanding of the prevalence and form of spatial density dependence in natural populations. PMID:15590593

  18. Comprehension of Spatial Language in Williams Syndrome: Evidence for Impaired Spatial Representation of Verbal Descriptions

    ERIC Educational Resources Information Center

    Laing, Emma; Jarrold, Christopher

    2007-01-01

    Individuals with the rare genetic disorder, Williams syndrome, have an unusual cognitive profile with relatively good language abilities but poor non-verbal and spatial skills. This study explored the interaction between linguistic and spatial functioning in Williams syndrome by investigating individuals' comprehension of spatial language. A group…

  19. Task-dependent activations of human auditory cortex during spatial discrimination and spatial memory tasks.

    PubMed

    Rinne, Teemu; Koistinen, Sonja; Talja, Suvi; Wikman, Patrik; Salonen, Oili

    2012-02-15

    In the present study, we applied high-resolution functional magnetic resonance imaging (fMRI) of the human auditory cortex (AC) and adjacent areas to compare activations during spatial discrimination and spatial n-back memory tasks that were varied parametrically in difficulty. We found that activations in the anterior superior temporal gyrus (STG) were stronger during spatial discrimination than during spatial memory, while spatial memory was associated with stronger activations in the inferior parietal lobule (IPL). We also found that wide AC areas were strongly deactivated during the spatial memory tasks. The present AC activation patterns associated with spatial discrimination and spatial memory tasks were highly similar to those obtained in our previous study comparing AC activations during pitch discrimination and pitch memory (Rinne et al., 2009). Together our previous and present results indicate that discrimination and memory tasks activate anterior and posterior AC areas differently and that this anterior-posterior division is present both when these tasks are performed on spatially invariant (pitch discrimination vs. memory) or spatially varying (spatial discrimination vs. memory) sounds. These results also further strengthen the view that activations of human AC cannot be explained only by stimulus-level parameters (e.g., spatial vs. nonspatial stimuli) but that the activations observed with fMRI are strongly dependent on the characteristics of the behavioral task. Thus, our results suggest that in order to understand the functional structure of AC a more systematic investigation of task-related factors affecting AC activations is needed.

  20. Plasticity of Human Spatial Cognition: Spatial Language and Cognition Covary across Cultures

    ERIC Educational Resources Information Center

    Haun, Daniel B. M.; Rapold, Christian J.; Janzen, Gabriele; Levinson, Stephen C.

    2011-01-01

    The present paper explores cross-cultural variation in spatial cognition by comparing spatial reconstruction tasks by Dutch and Namibian elementary school children. These two communities differ in the way they predominantly express spatial relations in language. Four experiments investigate cognitive strategy preferences across different levels of…

  1. Developing Spatial Orientation and Spatial Memory with a Treasure Hunting Game

    ERIC Educational Resources Information Center

    Lin, Chien-Heng; Chen, Chien-Min; Lou, Yu-Chiung

    2014-01-01

    The abilities of both spatial orientation and spatial memory play very important roles in human navigation and spatial cognition. Since such abilities are difficult to strengthen through books or classroom instruction, there are no particular curricula or methods to assist in their development. Therefore, this study develops a spatial…

  2. The Role of Visuo-Spatial Abilities in Recall of Spatial Descriptions: A Mediation Model

    ERIC Educational Resources Information Center

    Meneghetti, Chiara; De Beni, Rossana; Pazzaglia, Francesca; Gyselinck, Valerie

    2011-01-01

    This research investigates how visuo-spatial abilities (such as mental rotation--MR--and visuo-spatial working memory--VSWM--) work together to influence the recall of environmental descriptions. We tested a mediation model in which VSWM was assumed to mediate the relationship between MR and spatial text recall. First, 120 participants were…

  3. Spatial Working Memory Interferes with Explicit, but Not Probabilistic Cuing of Spatial Attention

    ERIC Educational Resources Information Center

    Won, Bo-Yeong; Jiang, Yuhong V.

    2015-01-01

    Recent empirical and theoretical work has depicted a close relationship between visual attention and visual working memory. For example, rehearsal in spatial working memory depends on spatial attention, whereas adding a secondary spatial working memory task impairs attentional deployment in visual search. These findings have led to the proposal…

  4. The neural basis for spatial relations.

    PubMed

    Amorapanth, Prin X; Widick, Page; Chatterjee, Anjan

    2010-08-01

    Studies in semantics traditionally focus on knowledge of objects. By contrast, less is known about how objects relate to each other. In an fMRI study, we tested the hypothesis that the neural processing of categorical spatial relations between objects is distinct from the processing of the identity of objects. Attending to the categorical spatial relations compared with attending to the identity of objects resulted in greater activity in superior and inferior parietal cortices (especially on the left) and posterior middle frontal cortices bilaterally. In an accompanying lesion study, we tested the hypothesis that comparable areas would be necessary to represent categorical spatial relations and that the hemispheres differ in their biases to process categorical or coordinate spatial relations. Voxel-based lesion symptom mapping results were consistent with the fMRI observations. Damage to a network comprising left inferior frontal, supramarginal, and angular gyri resulted in behavioral impairment on categorical spatial judgments. Homologous right brain damage also produced such deficits, albeit less severely. The reverse pattern was observed for coordinate spatial processing. Right brain damage to the middle temporal gyrus produced more severe deficits than left hemisphere damage. Additional analyses suggested that some areas process both kinds of spatial relations conjointly and others distinctly. The left angular and inferior frontal gyrus processes coordinate spatial information over and above the categorical processing. The anterior superior temporal gyrus appears to process categorical spatial information uniquely. No areas within the right hemisphere processed categorical spatial information uniquely. Taken together, these findings suggest that the functional neuroanatomy of categorical and coordinate processing is more nuanced than implied by a simple hemispheric dichotomy.

  5. Solving Large-scale Spatial Optimization Problems in Water Resources Management through Spatial Evolutionary Algorithms

    NASA Astrophysics Data System (ADS)

    Wang, J.; Cai, X.

    2007-12-01

    A water resources system can be defined as a large-scale spatial system, within which distributed ecological system interacts with the stream network and ground water system. Water resources management, the causative factors and hence the solutions to be developed have a significant spatial dimension. This motivates a modeling analysis of water resources management within a spatial analytical framework, where data is usually geo- referenced and in the form of a map. One of the important functions of Geographic information systems (GIS) is to identify spatial patterns of environmental variables. The role of spatial patterns in water resources management has been well established in the literature particularly regarding how to design better spatial patterns for satisfying the designated objectives of water resources management. Evolutionary algorithms (EA) have been demonstrated to be successful in solving complex optimization models for water resources management due to its flexibility to incorporate complex simulation models in the optimal search procedure. The idea of combining GIS and EA motivates the development and application of spatial evolutionary algorithms (SEA). SEA assimilates spatial information into EA, and even changes the representation and operators of EA. In an EA used for water resources management, the mathematical optimization model should be modified to account the spatial patterns; however, spatial patterns are usually implicit, and it is difficult to impose appropriate patterns to spatial data. Also it is difficult to express complex spatial patterns by explicit constraints included in the EA. The GIS can help identify the spatial linkages and correlations based on the spatial knowledge of the problem. These linkages are incorporated in the fitness function for the preference of the compatible vegetation distribution. Unlike a regular GA for spatial models, the SEA employs a special hierarchical hyper-population and spatial genetic operators

  6. Spectral-spatial hyperspectral image classification using super-pixel-based spatial pyramid representation

    NASA Astrophysics Data System (ADS)

    Fan, Jiayuan; Tan, Hui Li; Toomik, Maria; Lu, Shijian

    2016-10-01

    Spatial pyramid matching has demonstrated its power for image recognition task by pooling features from spatially increasingly fine sub-regions. Motivated by the concept of feature pooling at multiple pyramid levels, we propose a novel spectral-spatial hyperspectral image classification approach using superpixel-based spatial pyramid representation. This technique first generates multiple superpixel maps by decreasing the superpixel number gradually along with the increased spatial regions for labelled samples. By using every superpixel map, sparse representation of pixels within every spatial region is then computed through local max pooling. Finally, features learned from training samples are aggregated and trained by a support vector machine (SVM) classifier. The proposed spectral-spatial hyperspectral image classification technique has been evaluated on two public hyperspectral datasets, including the Indian Pines image containing 16 different agricultural scene categories with a 20m resolution acquired by AVIRIS and the University of Pavia image containing 9 land-use categories with a 1.3m spatial resolution acquired by the ROSIS-03 sensor. Experimental results show significantly improved performance compared with the state-of-the-art works. The major contributions of this proposed technique include (1) a new spectral-spatial classification approach to generate feature representation for hyperspectral image, (2) a complementary yet effective feature pooling approach, i.e. the superpixel-based spatial pyramid representation that is used for the spatial correlation study, (3) evaluation on two public hyperspectral image datasets with superior image classification performance.

  7. Exploring the Structure of Spatial Representations

    PubMed Central

    Madl, Tamas; Franklin, Stan; Chen, Ke; Trappl, Robert; Montaldi, Daniela

    2016-01-01

    It has been suggested that the map-like representations that support human spatial memory are fragmented into sub-maps with local reference frames, rather than being unitary and global. However, the principles underlying the structure of these ‘cognitive maps’ are not well understood. We propose that the structure of the representations of navigation space arises from clustering within individual psychological spaces, i.e. from a process that groups together objects that are close in these spaces. Building on the ideas of representational geometry and similarity-based representations in cognitive science, we formulate methods for learning dissimilarity functions (metrics) characterizing participants’ psychological spaces. We show that these learned metrics, together with a probabilistic model of clustering based on the Bayesian cognition paradigm, allow prediction of participants’ cognitive map structures in advance. Apart from insights into spatial representation learning in human cognition, these methods could facilitate novel computational tools capable of using human-like spatial concepts. We also compare several features influencing spatial memory structure, including spatial distance, visual similarity and functional similarity, and report strong correlations between these dimensions and the grouping probability in participants’ spatial representations, providing further support for clustering in spatial memory. PMID:27347681

  8. Bibliography of spatial interferometry in optical astronomy

    NASA Technical Reports Server (NTRS)

    Gezari, Daniel Y.; Roddier, Francois; Roddier, Claude

    1990-01-01

    The Bibliography of Spatial Interferometry in Optical Astronomy is a guide to the published literature in applications of spatial interferometry techniques to astronomical observations, theory and instrumentation at visible and infrared wavelengths. The key words spatial and optical define the scope of this discipline, distinguishing it from spatial interferometry at radio wavelengths, interferometry in the frequency domain applied to spectroscopy, or more general electro-optics theoretical and laboratory research. The main bibliography is a listing of all technical articles published in the international scientific literature and presented at the major international meetings and workshops attended by the spatial interferometry community. Section B summarizes publications dealing with the basic theoretical concepts and algorithms proposed and applied to optical spatial interferometry and imaging through a turbulent atmosphere. The section on experimental techniques is divided into twelve categories, representing the most clearly identified major areas of experimental research work. Section D, Observations, identifies publications dealing specifically with observations of astronomical sources, in which optical spatial interferometry techniques have been applied.

  9. Spatial learning and goldfish telencephalon NMDA receptors.

    PubMed

    Gómez, Yolanda; Vargas, Juan Pedro; Portavella, Manuel; López, Juan Carlos

    2006-05-01

    Recent results have demonstrated that the mammalian hippocampus and the dorso-lateral telencephalon of ray-finned fishes share functional similarities in relation to spatial memory systems. In the present study, we investigated whether the physiological mechanisms of this hippocampus-dependent spatial memory system were also similar in mammals and ray-finned fishes, and therefore possibly conserved through evolution in vertebrates. In Experiment 1, we studied the effects of the intracranial administration of the noncompetitive NMDA receptor antagonist MK-801 during the acquisition of a spatial task. The results indicated dose-dependent drug-induced impairment of spatial memory. Experiment 2 evaluated if the MK-801 produced disruption of retrieval of a learned spatial response. Data showed that the administration of MK-801 did not impair the retrieval of the information previously stored. The last experiment analyzed the involvement of the telencephalic NMDA receptors in a spatial and in a cue task. Results showed a clear impairment in spatial learning but not in cue learning when NMDA receptors were blocked. As a whole, these results indicate that physiological mechanisms of this hippocampus-dependent system could be a general feature in vertebrate, and therefore phylogenetically conserved.

  10. Spatial constancy mechanisms in motor control

    PubMed Central

    Medendorp, W. Pieter

    2011-01-01

    The success of the human species in interacting with the environment depends on the ability to maintain spatial stability despite the continuous changes in sensory and motor inputs owing to movements of eyes, head and body. In this paper, I will review recent advances in the understanding of how the brain deals with the dynamic flow of sensory and motor information in order to maintain spatial constancy of movement goals. The first part summarizes studies in the saccadic system, showing that spatial constancy is governed by a dynamic feed-forward process, by gaze-centred remapping of target representations in anticipation of and across eye movements. The subsequent sections relate to other oculomotor behaviour, such as eye–head gaze shifts, smooth pursuit and vergence eye movements, and their implications for feed-forward mechanisms for spatial constancy. Work that studied the geometric complexities in spatial constancy and saccadic guidance across head and body movements, distinguishing between self-generated and passively induced motion, indicates that both feed-forward and sensory feedback processing play a role in spatial updating of movement goals. The paper ends with a discussion of the behavioural mechanisms of spatial constancy for arm motor control and their physiological implications for the brain. Taken together, the emerging picture is that the brain computes an evolving representation of three-dimensional action space, whose internal metric is updated in a nonlinear way, by optimally integrating noisy and ambiguous afferent and efferent signals. PMID:21242137

  11. Abstract Spatial Reasoning as an Autistic Strength

    PubMed Central

    Stevenson, Jennifer L.; Gernsbacher, Morton Ann

    2013-01-01

    Autistic individuals typically excel on spatial tests that measure abstract reasoning, such as the Block Design subtest on intelligence test batteries and the Raven’s Progressive Matrices nonverbal test of intelligence. Such well-replicated findings suggest that abstract spatial processing is a relative and perhaps absolute strength of autistic individuals. However, previous studies have not systematically varied reasoning level – concrete vs. abstract – and test domain – spatial vs. numerical vs. verbal, which the current study did. Autistic participants (N = 72) and non-autistic participants (N = 72) completed a battery of 12 tests that varied by reasoning level (concrete vs. abstract) and domain (spatial vs. numerical vs. verbal). Autistic participants outperformed non-autistic participants on abstract spatial tests. Non-autistic participants did not outperform autistic participants on any of the three domains (spatial, numerical, and verbal) or at either of the two reasoning levels (concrete and abstract), suggesting similarity in abilities between autistic and non-autistic individuals, with abstract spatial reasoning as an autistic strength. PMID:23533615

  12. Remote state preparation of spatial qubits

    SciTech Connect

    Solis-Prosser, M. A.; Neves, L.

    2011-07-15

    We study the quantum communication protocol of remote state preparation (RSP) for pure states of qubits encoded in single photons transmitted through a double slit, the so-called spatial qubits. Two measurement strategies that one can adopt to remotely prepare the states are discussed. The first strategy is the well-known spatial postselection, where a single-pixel detector measures the transverse position of the photon between the focal and the image plane of a lens. The second strategy, proposed by ourselves, is a generalized measurement divided into two steps: the implementation of a two-outcome positive operator-valued measurement (POVM) followed by the spatial postselection at the focal plane of the lens by a two-pixel detector in each output of the POVM. In both cases we analyze the effects of the finite spatial resolution of the detectors over three figures of merit of the protocol, namely, the probability of preparation, the fidelity, and purity of the remotely prepared states. It is shown that our strategy improves these figures compared with spatial postselection, at the expense of increasing the classical communication cost as well as the required experimental resources. In addition, we present a modified version of our strategy for RSP of spatial qudits which is able to prepare arbitrary pure states, unlike spatial postselection alone. We expect that our study may also be extended for RSP of the angular spectrum of a single-photon field as an alternative for quantum teleportation which requires very inefficient nonlinear interactions.

  13. Sensorial countermeasures for vestibular spatial disorientation.

    PubMed

    Paillard, Aurore C; Quarck, Gaëlle; Denise, Pierre

    2014-05-01

    Spatial disorientation is defined as an erroneous body orientation perceived by pilots during flights. Limits of the vestibular system provoke frequent spatial disorientation mishaps. Although vestibular spatial disorientation is experienced frequently in aviation, there is no intuitive countermeasure against spatial disorientation mishaps to date. The aim of this review is to describe the current sensorial countermeasures and to examine future leads in sensorial ergonomics for vestibular spatial disorientation. This work reviews: 1) the visual ergonomics, 2) the vestibular countermeasures, 3) the auditory displays, 4) the somatosensory countermeasures, and, finally, 5) the multisensory displays. This review emphasizes the positive aspects of auditory and somatosensory countermeasures as well as multisensory devices. Even if some aspects such as sensory conflict and motion sickness need to be assessed, these countermeasures should be taken into consideration for ergonomics work in the future. However, a recent development in aviation might offer new and better perspectives: unmanned aerial vehicles. Unmanned aerial vehicles aim to go beyond the physiological boundaries of human sensorial systems and would allow for coping with spatial disorientation and motion sickness. Even if research is necessary to improve the interaction between machines and humans, this recent development might be incredibly useful for decreasing or even stopping vestibular spatial disorientation.

  14. Rasdaman for Big Spatial Raster Data

    NASA Astrophysics Data System (ADS)

    Hu, F.; Huang, Q.; Scheele, C. J.; Yang, C. P.; Yu, M.; Liu, K.

    2015-12-01

    Spatial raster data have grown exponentially over the past decade. Recent advancements on data acquisition technology, such as remote sensing, have allowed us to collect massive observation data of various spatial resolution and domain coverage. The volume, velocity, and variety of such spatial data, along with the computational intensive nature of spatial queries, pose grand challenge to the storage technologies for effective big data management. While high performance computing platforms (e.g., cloud computing) can be used to solve the computing-intensive issues in big data analysis, data has to be managed in a way that is suitable for distributed parallel processing. Recently, rasdaman (raster data manager) has emerged as a scalable and cost-effective database solution to store and retrieve massive multi-dimensional arrays, such as sensor, image, and statistics data. Within this paper, the pros and cons of using rasdaman to manage and query spatial raster data will be examined and compared with other common approaches, including file-based systems, relational databases (e.g., PostgreSQL/PostGIS), and NoSQL databases (e.g., MongoDB and Hive). Earth Observing System (EOS) data collected from NASA's Atmospheric Scientific Data Center (ASDC) will be used and stored in these selected database systems, and a set of spatial and non-spatial queries will be designed to benchmark their performance on retrieving large-scale, multi-dimensional arrays of EOS data. Lessons learnt from using rasdaman will be discussed as well.

  15. Spatial language facilitates spatial cognition: evidence from children who lack language input.

    PubMed

    Gentner, Dedre; Ozyürek, Asli; Gürcanli, Ozge; Goldin-Meadow, Susan

    2013-06-01

    Does spatial language influence how people think about space? To address this question, we observed children who did not know a conventional language, and tested their performance on nonlinguistic spatial tasks. We studied deaf children living in Istanbul whose hearing losses prevented them from acquiring speech and whose hearing parents had not exposed them to sign. Lacking a conventional language, the children used gestures, called homesigns, to communicate. In Study 1, we asked whether homesigners used gesture to convey spatial relations, and found that they did not. In Study 2, we tested a new group of homesigners on a Spatial Mapping Task, and found that they performed significantly worse than hearing Turkish children who were matched to the deaf children on another cognitive task. The absence of spatial language thus went hand-in-hand with poor performance on the nonlinguistic spatial task, pointing to the importance of spatial language in thinking about space.

  16. Spatial Inferences in Narrative Comprehension: the Role of Verbal and Spatial Working Memory.

    PubMed

    Irrazabal, Natalia; Burin, Debora

    2016-03-14

    During the comprehension of narrative texts, readers keep a mental representation of the location of protagonists and objects; a breach in spatial coherence is detected by longer online reading times (consistency effect). We addressed whether these spatial inferences involve verbal or spatial working memory in two experiments, combining the consistency paradigm with selective verbal and spatial working memory concurrent tasks. The first experiment found longer reading times with a concurrent spatial task under imagery instructions (t33 = 2.87, p = .021). The second experiment, under comprehension reading instructions, found effects of verbal interference on reading times and accuracy. With a verbal secondary task, reading times for the target sentence were shorter (t45 = 3.60, p = .004) and the error rate was significantly higher (t47 = 2.95, p = .005) than without interference. This pattern of results suggests that spatial inferences in narrative comprehension rely mainly on verbal resources, and spatial working memory resources are recruited when imagery is required.

  17. Spatial short-term memory in children with nonverbal learning disabilities: impairment in encoding spatial configuration.

    PubMed

    Narimoto, Tadamasa; Matsuura, Naomi; Takezawa, Tomohiro; Mitsuhashi, Yoshinori; Hiratani, Michio

    2013-01-01

    The authors investigated whether impaired spatial short-term memory exhibited by children with nonverbal learning disabilities is due to a problem in the encoding process. Children with or without nonverbal learning disabilities performed a simple spatial test that required them to remember 3, 5, or 7 spatial items presented simultaneously in random positions (i.e., spatial configuration) and to decide if a target item was changed or all items including the target were in the same position. The results showed that, even when the spatial positions in the encoding and probe phases were similar, the mean proportion correct of children with nonverbal learning disabilities was 0.58 while that of children without nonverbal learning disabilities was 0.84. The authors argue with the results that children with nonverbal learning disabilities have difficulty encoding relational information between spatial items, and that this difficulty is responsible for their impaired spatial short-term memory.

  18. Semantic Metadata for Heterogeneous Spatial Planning Documents

    NASA Astrophysics Data System (ADS)

    Iwaniak, A.; Kaczmarek, I.; Łukowicz, J.; Strzelecki, M.; Coetzee, S.; Paluszyński, W.

    2016-09-01

    Spatial planning documents contain information about the principles and rights of land use in different zones of a local authority. They are the basis for administrative decision making in support of sustainable development. In Poland these documents are published on the Web according to a prescribed non-extendable XML schema, designed for optimum presentation to humans in HTML web pages. There is no document standard, and limited functionality exists for adding references to external resources. The text in these documents is discoverable and searchable by general-purpose web search engines, but the semantics of the content cannot be discovered or queried. The spatial information in these documents is geographically referenced but not machine-readable. Major manual efforts are required to integrate such heterogeneous spatial planning documents from various local authorities for analysis, scenario planning and decision support. This article presents results of an implementation using machine-readable semantic metadata to identify relationships among regulations in the text, spatial objects in the drawings and links to external resources. A spatial planning ontology was used to annotate different sections of spatial planning documents with semantic metadata in the Resource Description Framework in Attributes (RDFa). The semantic interpretation of the content, links between document elements and links to external resources were embedded in XHTML pages. An example and use case from the spatial planning domain in Poland is presented to evaluate its efficiency and applicability. The solution enables the automated integration of spatial planning documents from multiple local authorities to assist decision makers with understanding and interpreting spatial planning information. The approach is equally applicable to legal documents from other countries and domains, such as cultural heritage and environmental management.

  19. Spatial occupancy models for large data sets

    USGS Publications Warehouse

    Johnson, Devin S.; Conn, Paul B.; Hooten, Mevin B.; Ray, Justina C.; Pond, Bruce A.

    2013-01-01

    Since its development, occupancy modeling has become a popular and useful tool for ecologists wishing to learn about the dynamics of species occurrence over time and space. Such models require presence–absence data to be collected at spatially indexed survey units. However, only recently have researchers recognized the need to correct for spatially induced overdisperison by explicitly accounting for spatial autocorrelation in occupancy probability. Previous efforts to incorporate such autocorrelation have largely focused on logit-normal formulations for occupancy, with spatial autocorrelation induced by a random effect within a hierarchical modeling framework. Although useful, computational time generally limits such an approach to relatively small data sets, and there are often problems with algorithm instability, yielding unsatisfactory results. Further, recent research has revealed a hidden form of multicollinearity in such applications, which may lead to parameter bias if not explicitly addressed. Combining several techniques, we present a unifying hierarchical spatial occupancy model specification that is particularly effective over large spatial extents. This approach employs a probit mixture framework for occupancy and can easily accommodate a reduced-dimensional spatial process to resolve issues with multicollinearity and spatial confounding while improving algorithm convergence. Using open-source software, we demonstrate this new model specification using a case study involving occupancy of caribou (Rangifer tarandus) over a set of 1080 survey units spanning a large contiguous region (108 000 km2) in northern Ontario, Canada. Overall, the combination of a more efficient specification and open-source software allows for a facile and stable implementation of spatial occupancy models for large data sets.

  20. SPATIAL AND SPECTRAL RESOLUTION IN GEOBOTANY.

    USGS Publications Warehouse

    Milton, Nancy M.; Mouat, D.A.

    1984-01-01

    Remotely sensed data are now available from a wide variety of instruments, each data set having a particular spectral and spatial resolution. The changes in vegetation associated with changes in lithology or the presence of mineral deposits can also occur at different scales. The task of geobotanical remote sensing is to choose or adapt the remotely sensed data to the appropriate geobotanical technique to solve the geological problem of interest. Examples are given of a number of applications of data sets of different spectral and spatial resolution. The relative importance of spectral and spatial resolution is discussed.

  1. Spatial transformations: from fundamentals to applications

    PubMed Central

    Foster, Robert; Grant, Patrick; Hao, Yang; Hibbins, Alastair; Philbin, Thomas; Sambles, Roy

    2015-01-01

    This paper forms the introduction to this themed issue of Philosophical Transactions of the Royal Society A on ‘Spatial transformations’, arising from the Royal Society Scientific Discussion Meeting held in January 2015. The paper begins with a review of the concepts and history of spatial transformations, followed by a discussion of the contributions from the papers in this themed issue. A summary of the advantages and current limitations of spatial transformations concludes the paper, with the key challenges identified at the Scientific Discussion Meeting also given. PMID:26217061

  2. Hippocampus and neocortex: recognition and spatial memory.

    PubMed

    Vann, Seralynne D; Albasser, Mathieu M

    2011-06-01

    Recognition and spatial memory are typically associated with the perirhinal cortex and hippocampal formation, respectively. Solely focusing on these structures for these specific mnemonic functions may, however, be limiting progress in the field. The distinction between these subdivisions of memory is becoming less defined as, for example, hippocampal cells traditionally considered to encode locations also encode place-object associations. There is increasing evidence for the involvement of overlapping networks of brain structures for aspects of both spatial and recognition memory. Future models of spatial and recognition memory will have to extend beyond the hippocampus and perirhinal cortex to incorporate a wider network of cortical and subcortical structures.

  3. Spatial transformations: from fundamentals to applications.

    PubMed

    Foster, Robert; Grant, Patrick; Hao, Yang; Hibbins, Alastair; Philbin, Thomas; Sambles, Roy

    2015-08-28

    This paper forms the introduction to this themed issue of Philosophical Transactions of the Royal Society A on 'Spatial transformations', arising from the Royal Society Scientific Discussion Meeting held in January 2015. The paper begins with a review of the concepts and history of spatial transformations, followed by a discussion of the contributions from the papers in this themed issue. A summary of the advantages and current limitations of spatial transformations concludes the paper, with the key challenges identified at the Scientific Discussion Meeting also given.

  4. Spatial adaptation on video display terminals

    SciTech Connect

    Greenhouse, D.S.; Bailey, I.L.; Howarth, P.A.; Berman, S.M.

    1989-01-01

    Spatial adaptation, in the form of a frequency-specific reduction in contrast sensitivity, can occur when the visual system is exposed to certain stimuli. We employed vertical sinusoidal test gratings to investigate adaptation to the horizontal structure of text presented on a standard video display terminal. The parameters of the contrast sensitivity test were selected on the basis of waveform analysis of spatial luminance scans of the text stimulus. We found that subjects exhibited a small, but significant, frequency-specific adaptation consistent with the spatial frequency spectrum of the stimulus. Theoretical and practical significance of this finding are discussed. 6 refs., 4 figs.

  5. The Role of Spatial Ability and Achievement in Organic Chemistry.

    ERIC Educational Resources Information Center

    Pribyl, Jeffrey R.; Bodner, George M.

    This study investigated the role that spatial ability has in achievement in organic chemistry. Spatial ability was defined as containing two subfactors--spatial visualization and spatial orientation. Spatial visualization is the ability to mentally manipulate pictorially presented stimuli; involved in the processes of manipulation are the…

  6. Multichannel spatial auditory display for speech communications

    NASA Technical Reports Server (NTRS)

    Begault, D. R.; Erbe, T.; Wenzel, E. M. (Principal Investigator)

    1994-01-01

    A spatial auditory display for multiple speech communications was developed at NASA/Ames Research Center. Input is spatialized by the use of simplified head-related transfer functions, adapted for FIR filtering on Motorola 56001 digital signal processors. Hardware and firmware design implementations are overviewed for the initial prototype developed for NASA-Kennedy Space Center. An adaptive staircase method was used to determine intelligibility levels of four-letter call signs used by launch personnel at NASA against diotic speech babble. Spatial positions at 30 degrees azimuth increments were evaluated. The results from eight subjects showed a maximum intelligibility improvement of about 6-7 dB when the signal was spatialized to 60 or 90 degrees azimuth positions.

  7. Spatial Relational Memory Requires Hippocampal Adult Neurogenesis

    PubMed Central

    Koehl, Muriel; Ichas, François; De Giorgi, Francesca; Costet, Pierre; Abrous, Djoher Nora; Piazza, Pier Vincenzo

    2008-01-01

    The dentate gyrus of the hippocampus is one of the few regions of the mammalian brain where new neurons are generated throughout adulthood. This adult neurogenesis has been proposed as a novel mechanism that mediates spatial memory. However, data showing a causal relationship between neurogenesis and spatial memory are controversial. Here, we developed an inducible transgenic strategy allowing specific ablation of adult-born hippocampal neurons. This resulted in an impairment of spatial relational memory, which supports a capacity for flexible, inferential memory expression. In contrast, less complex forms of spatial knowledge were unaltered. These findings demonstrate that adult-born neurons are necessary for complex forms of hippocampus-mediated learning. PMID:18509506

  8. Spatial Allocator for air quality modeling

    EPA Pesticide Factsheets

    The Spatial Allocator is a set of tools that helps users manipulate and generate data files related to emissions and air quality modeling without requiring the use of a commercial Geographic Information System.

  9. Modularizing Spatial Ontologies for Assisted Living Systems

    NASA Astrophysics Data System (ADS)

    Hois, Joana

    Assisted living systems are intended to support daily-life activities in user homes by automatizing and monitoring behavior of the environment while interacting with the user in a non-intrusive way. The knowledge base of such systems therefore has to define thematically different aspects of the environment mostly related to space, such as basic spatial floor plan information, pieces of technical equipment in the environment and their functions and spatial ranges, activities users can perform, entities that occur in the environment, etc. In this paper, we present thematically different ontologies, each of which describing environmental aspects from a particular perspective. The resulting modular structure allows the selection of application-specific ontologies as necessary. This hides information and reduces complexity in terms of the represented spatial knowledge and reasoning practicability. We motivate and present the different spatial ontologies applied to an ambient assisted living application.

  10. Developing Spatial Sense and Communication Skills

    ERIC Educational Resources Information Center

    Richardson, Kerri; Stein, Catherine

    2008-01-01

    This article describes how spatial instruction with preservice teachers can be implemented in a middle-grades mathematics methods class. A "Reflect and Discuss" section is included for professional development study. (Contains 4 figures.)

  11. Architectural Implications for Spatial Object Association Algorithms

    SciTech Connect

    Kumar, V S; Kurc, T; Saltz, J; Abdulla, G; Kohn, S R; Matarazzo, C

    2009-01-29

    Spatial object association, also referred to as cross-match of spatial datasets, is the problem of identifying and comparing objects in two or more datasets based on their positions in a common spatial coordinate system. In this work, we evaluate two crossmatch algorithms that are used for astronomical sky surveys, on the following database system architecture configurations: (1) Netezza Performance Server R, a parallel database system with active disk style processing capabilities, (2) MySQL Cluster, a high-throughput network database system, and (3) a hybrid configuration consisting of a collection of independent database system instances with data replication support. Our evaluation provides insights about how architectural characteristics of these systems affect the performance of the spatial crossmatch algorithms. We conducted our study using real use-case scenarios borrowed from a large-scale astronomy application known as the Large Synoptic Survey Telescope (LSST).

  12. Spatial distribution of thermal energy in equilibrium.

    PubMed

    Bar-Sinai, Yohai; Bouchbinder, Eran

    2015-06-01

    The equipartition theorem states that in equilibrium, thermal energy is equally distributed among uncoupled degrees of freedom that appear quadratically in the system's Hamiltonian. However, for spatially coupled degrees of freedom, such as interacting particles, one may speculate that the spatial distribution of thermal energy may differ from the value predicted by equipartition, possibly quite substantially in strongly inhomogeneous or disordered systems. Here we show that for systems undergoing simple Gaussian fluctuations around an equilibrium state, the spatial distribution is universally bounded from above by 1/2k(B)T. We further show that in one-dimensional systems with short-range interactions, the thermal energy is equally partitioned even for coupled degrees of freedom in the thermodynamic limit and that in higher dimensions nontrivial spatial distributions emerge. Some implications are discussed.

  13. Users as essential contributors to spatial cyberinfrastructures.

    PubMed

    Poore, Barbara S

    2011-04-05

    Current accounts of spatial cyberinfrastructure development tend to overemphasize technologies to the neglect of critical social and cultural issues on which adoption depends. Spatial cyberinfrastructures will have a higher chance of success if users of many types, including nonprofessionals, are made central to the development process. Recent studies in the history of infrastructures reveal key turning points and issues that should be considered in the development of spatial cyberinfrastructure projects. These studies highlight the importance of adopting qualitative research methods to learn how users work with data and digital tools, and how user communities form. The author's empirical research on data sharing networks in the Pacific Northwest salmon crisis at the turn of the 21st century demonstrates that ordinary citizens can contribute critical local knowledge to global databases and should be considered in the design and construction of spatial cyberinfrastructures.

  14. Superior colliculus and visual spatial attention.

    PubMed

    Krauzlis, Richard J; Lovejoy, Lee P; Zénon, Alexandre

    2013-07-08

    The superior colliculus (SC) has long been known to be part of the network of brain areas involved in spatial attention, but recent findings have dramatically refined our understanding of its functional role. The SC both implements the motor consequences of attention and plays a crucial role in the process of target selection that precedes movement. Moreover, even in the absence of overt orienting movements, SC activity is related to shifts of covert attention and is necessary for the normal control of spatial attention during perceptual judgments. The neuronal circuits that link the SC to spatial attention may include attention-related areas of the cerebral cortex, but recent results show that the SC's contribution involves mechanisms that operate independently of the established signatures of attention in visual cortex. These findings raise new issues and suggest novel possibilities for understanding the brain mechanisms that enable spatial attention.

  15. Users as essential contributors to spatial cyberinfrastructures

    USGS Publications Warehouse

    Poore, B.S.

    2011-01-01

    Current accounts of spatial cyberinfrastructure development tend to overemphasize technologies to the neglect of critical social and cultural issues on which adoption depends. Spatial cyberinfrastructures will have a higher chance of success if users of many types, including nonprofessionals, are made central to the development process. Recent studies in the history of infrastructures reveal key turning points and issues that should be considered in the development of spatial cyberinfrastructure projects. These studies highlight the importance of adopting qualitative research methods to learn how users work with data and digital tools, and how user communities form. The author's empirical research on data sharing networks in the Pacific Northwest salmon crisis at the turn of the 21st century demonstrates that ordinary citizens can contribute critical local knowledge to global databases and should be considered in the design and construction of spatial cyberinfrastructures.

  16. Users as essential contributors to spatial cyberinfrastructures

    PubMed Central

    Poore, Barbara S.

    2011-01-01

    Current accounts of spatial cyberinfrastructure development tend to overemphasize technologies to the neglect of critical social and cultural issues on which adoption depends. Spatial cyberinfrastructures will have a higher chance of success if users of many types, including nonprofessionals, are made central to the development process. Recent studies in the history of infrastructures reveal key turning points and issues that should be considered in the development of spatial cyberinfrastructure projects. These studies highlight the importance of adopting qualitative research methods to learn how users work with data and digital tools, and how user communities form. The author's empirical research on data sharing networks in the Pacific Northwest salmon crisis at the turn of the 21st century demonstrates that ordinary citizens can contribute critical local knowledge to global databases and should be considered in the design and construction of spatial cyberinfrastructures. PMID:21444825

  17. Data Quality Statements for Spatial Databases

    DTIC Science & Technology

    1992-07-01

    approaches; one emanating from the Digital Chart of the World Project and one through a working party within the International Cartographic Association.... Spatial data, Quality, Geographic information systems, Digital image processing.

  18. a New Spatial and Temporal Fusion Model

    NASA Astrophysics Data System (ADS)

    Wang, Jing; Huang, Bo

    2016-06-01

    As Moderate Resolution Imaging Spectroradiometer (MODIS) and Enhanced Thematic Mapper Plus (ETM+) has a tradeoff between the high temporal resolution and high spatial resolution, this paper proposed a spatial and temporal model with auto-regression error correction (AREC) method to blend the two types of images in order to obtain the composed image with both high spatial and temporal resolution. Experiments and validation were conducted on a data set located in Shenzhen, China and compared with Spatial and Temporal Adaptive Reflectance Fusion Model (STARFM) in several objective indexes and visual analysis. It was found that AREC could effectively predict the land cover changes and the fusion results had better performances versus the ones of STARFM.

  19. Hedonic approaches based on spatial econometrics and spatial statistics: application to evaluation of project benefits

    NASA Astrophysics Data System (ADS)

    Tsutsumi, Morito; Seya, Hajime

    2009-12-01

    This study discusses the theoretical foundation of the application of spatial hedonic approaches—the hedonic approach employing spatial econometrics or/and spatial statistics—to benefits evaluation. The study highlights the limitations of the spatial econometrics approach since it uses a spatial weight matrix that is not employed by the spatial statistics approach. Further, the study presents empirical analyses by applying the Spatial Autoregressive Error Model (SAEM), which is based on the spatial econometrics approach, and the Spatial Process Model (SPM), which is based on the spatial statistics approach. SPMs are conducted based on both isotropy and anisotropy and applied to different mesh sizes. The empirical analysis reveals that the estimated benefits are quite different, especially between isotropic and anisotropic SPM and between isotropic SPM and SAEM; the estimated benefits are similar for SAEM and anisotropic SPM. The study demonstrates that the mesh size does not affect the estimated amount of benefits. Finally, the study provides a confidence interval for the estimated benefits and raises an issue with regard to benefit evaluation.

  20. Aging affects spatial reconstruction more than spatial pattern separation performance even after extended practice.

    PubMed

    Clark, Rachel; Tahan, Asli C; Watson, Patrick D; Severson, Joan; Cohen, Neal J; Voss, Michelle

    2017-03-21

    Although the hippocampus experiences age-related anatomical and functional deterioration, the effects of aging vary across hippocampal-dependent cognitive processes. In particular, whether or not the hippocampus is known to be required for a spatial memory process is not an accurate predictor on its own of whether aging will affect performance. Therefore, the primary objective of this study was to compare the effects of healthy aging on a test of spatial pattern separation and a test of spatial relational processing, which are two aspects of spatial memory that uniquely emphasize the use of multiple hippocampal-dependent processes. Spatial pattern separation supports spatial memory by preserving unique representations for distinct locations. Spatial relational processing forms relational representations of objects to locations or between objects and other objects in space. To test our primary objective, 30 young (18-30 years; 21F) and 30 older participants (60-80 years; 21F) all completed a spatial pattern separation task and a task designed to require spatial relational processing through spatial reconstruction. To ensure aging effects were not due to inadequate time to develop optimal strategies or become comfortable with the testing devices, a subset of participants had extended practice across three sessions on each task. Results showed that older adults performed more poorly than young on the spatial reconstruction task that emphasized the use of spatial relational processing, and that age effects persisted even after controlling for pattern separation performance. Further, older adults performed more poorly on spatial reconstruction than young adults even after three testing sessions each separated by 7-10 days, suggesting effects of aging are resistant to extended practice and likely reflect genuine decline in hippocampal memory abilities.

  1. Five challenges for spatial epidemic models

    PubMed Central

    Riley, Steven; Eames, Ken; Isham, Valerie; Mollison, Denis; Trapman, Pieter

    2015-01-01

    Infectious disease incidence data are increasingly available at the level of the individual and include high-resolution spatial components. Therefore, we are now better able to challenge models that explicitly represent space. Here, we consider five topics within spatial disease dynamics: the construction of network models; characterising threshold behaviour; modelling long-distance interactions; the appropriate scale for interventions; and the representation of population heterogeneity. PMID:25843387

  2. Visual-spatial ability in Parkinson's disease.

    PubMed

    Crucian, Gregory P; Okun, Michael S

    2003-09-01

    Parkinson's Disease (PD) has traditionally been viewed as primarily a disturbance of motor functioning, typically involving tremor, rigidity, hypokinesia, gait disturbance, and postural instability. More recently, decline in cognitive function has been recognized as a feature of PD. One prominent cognitive symptom of PD involves deficits on tasks of spatial ability. However, findings of visual-spatial deficits in individuals with PD have been inconsistent. There are several methodological issues in this area of research that potentially confound the interpretation of data and need to be taken into consideration, including subject characteristics (e.g., age, sex and education), duration of illness, the current level of disability, the presence of emotional depression, the current level of medications, and the presence of dementia. Further, the tests that have shown visual-spatial deficits in PD are often complex, showing sensitivity to other cognitive processes as well. Another problem in this area of research is the lack of a clear understanding of the brain mechanisms that underlie visual-spatial deficits in PD. One theory of cognitive dysfunction in PD suggests that these cognitive deficits are in some way related to disruption of frontal-basal ganglia neural circuits important in executive functions. However, frontal-basal ganglionic dysfunction does not appear to account entirely for the visual-spatial cognitive deficits seen in PD. Subtle differences in performance on executive function measures appear to dissociate individuals with frontal lobe damage from individuals with PD. Findings from two recent studies indicate that PD is indeed associated with deficits in visual-spatial ability. These findings also indicate that the relationship between visual-spatial ability and frontal-executive function in PD is likely complex, and that the visual-spatial deficits in PD may be sensitive to the sex of the individual with PD.

  3. Multisensory Integration for Pilot Spatial Orientation

    DTIC Science & Technology

    2006-09-01

    available to us with no information about the context of the flight other than it occurred at night and might have included the use of night vision ...Martin, E.L. (2000). Spatial disorientation in night vision goggle operations. San Antonio, TX: Spatial Disorientation Symposium. Found at: http...conditions, moonless night flights over the desert, and night vision goggle (NVG) use, are all known to be risk factors.22 Reminding pilots of the relevant

  4. Understanding the brain through its spatial structure

    NASA Astrophysics Data System (ADS)

    Morrison, Will Zachary

    The spatial location of cells in neural tissue can be easily extracted from many imaging modalities, but the information contained in spatial relationships between cells is seldom utilized. This is because of a lack of recognition of the importance of spatial relationships to some aspects of brain function, and the reflection in spatial statistics of other types of information. The mathematical tools necessary to describe spatial relationships are also unknown to many neuroscientists, and biologists in general. We analyze two cases, and show that spatial relationships can be used to understand the role of a particular type of cell, the astrocyte, in Alzheimer's disease, and that the geometry of axons in the brain's white matter sheds light on the process of establishing connectivity between areas of the brain. Astrocytes provide nutrients for neuronal metabolism, and regulate the chemical environment of the brain, activities that require manipulation of spatial distributions (of neurotransmitters, for example). We first show, through the use of a correlation function, that inter-astrocyte forces determine the size of independent regulatory domains in the cortex. By examining the spatial distribution of astrocytes in a mouse model of Alzheimer's Disease, we determine that astrocytes are not actively transported to fight the disease, as was previously thought. The paths axons take through the white matter determine which parts of the brain are connected, and how quickly signals are transmitted. The rules that determine these paths (i.e. shortest distance) are currently unknown. By measurement of axon orientation distributions using three-point correlation functions and the statistics of axon turning and branching, we reveal that axons are restricted to growth in three directions, like a taxicab traversing city blocks, albeit in three-dimensions. We show how geometric restrictions at the small scale are related to large-scale trajectories. Finally we discuss the

  5. Spatially Assisted Schwinger Mechanism and Magnetic Catalysis

    NASA Astrophysics Data System (ADS)

    Copinger, Patrick; Fukushima, Kenji

    2016-08-01

    Using the worldline formalism we compute an effective action for fermions under a temporally modulated electric field and a spatially modulated magnetic field. It is known that the former leads to an enhanced Schwinger mechanism, while we find that the latter can also result in enhanced particle production and even cause a reorganization of the vacuum to acquire a larger dynamical mass in equilibrium which spatially assists the magnetic catalysis.

  6. Building a North American Spatial Data Infrastructure

    USGS Publications Warehouse

    Coleman, D.J.; Nebert, D.D.

    1998-01-01

    This paper addresses the state of spatial data infrastructures within North America in late 1997. After providing some background underlying the philosophy and development of the SDI concept, the authors discuss effects of technology, institutions, and standardization that confront the cohesive implementation of a common infrastructure today. The paper concludes with a comparative framework and specific examples of elements and initiatives defining respective spatial data infrastructure initiatives in the United States and Canada.

  7. Categorical biases in perceiving spatial relations.

    PubMed

    Kranjec, Alexander; Lupyan, Gary; Chatterjee, Anjan

    2014-01-01

    We investigate the effect of spatial categories on visual perception. In three experiments, participants made same/different judgments on pairs of simultaneously presented dot-cross configurations. For different trials, the position of the dot within each cross could differ with respect to either categorical spatial relations (the dots occupied different quadrants) or coordinate spatial relations (the dots occupied different positions within the same quadrant). The dot-cross configurations also varied in how readily the dot position could be lexicalized. In harder-to-name trials, crosses formed a "+" shape such that each quadrant was associated with two discrete lexicalized spatial categories (e.g., "above" and "left"). In easier-to-name trials, both crosses were rotated 45° to form an "×" shape such that quadrants were unambiguously associated with a single lexicalized spatial category (e.g., "above" or "left"). In Experiment 1, participants were more accurate when discriminating categorical information between easier-to-name categories and more accurate at discriminating coordinate spatial information within harder-to-name categories. Subsequent experiments attempted to down-regulate or up-regulate the involvement of language in task performance. Results from Experiment 2 (verbal interference) and Experiment 3 (verbal training) suggest that the observed spatial relation type-by-nameability interaction is resistant to online language manipulations previously shown to affect color and object-based perceptual processing. The results across all three experiments suggest that robust biases in the visual perception of spatial relations correlate with patterns of lexicalization, but do not appear to be modulated by language online.

  8. Categorical Biases in Perceiving Spatial Relations

    PubMed Central

    Kranjec, Alexander; Lupyan, Gary; Chatterjee, Anjan

    2014-01-01

    We investigate the effect of spatial categories on visual perception. In three experiments, participants made same/different judgments on pairs of simultaneously presented dot-cross configurations. For different trials, the position of the dot within each cross could differ with respect to either categorical spatial relations (the dots occupied different quadrants) or coordinate spatial relations (the dots occupied different positions within the same quadrant). The dot-cross configurations also varied in how readily the dot position could be lexicalized. In harder-to-name trials, crosses formed a “+” shape such that each quadrant was associated with two discrete lexicalized spatial categories (e.g., “above” and “left”). In easier-to-name trials, both crosses were rotated 45° to form an “×” shape such that quadrants were unambiguously associated with a single lexicalized spatial category (e.g., “above” or “left”). In Experiment 1, participants were more accurate when discriminating categorical information between easier-to-name categories and more accurate at discriminating coordinate spatial information within harder-to-name categories. Subsequent experiments attempted to down-regulate or up-regulate the involvement of language in task performance. Results from Experiment 2 (verbal interference) and Experiment 3 (verbal training) suggest that the observed spatial relation type-by-nameability interaction is resistant to online language manipulations previously shown to affect color and object-based perceptual processing. The results across all three experiments suggest that robust biases in the visual perception of spatial relations correlate with patterns of lexicalization, but do not appear to be modulated by language online. PMID:24870560

  9. Exploiting Spatial Channel Occupancy Information in WLANs

    DTIC Science & Technology

    2014-05-15

    Exploiting Spatial Channel Occupancy Information in WLANs Michael N Krishnan Electrical Engineering and Computer Sciences University of California at...3. DATES COVERED 00-00-2014 to 00-00-2014 4. TITLE AND SUBTITLE Exploiting Spatial Channel Occupancy Information in WLANs 5a. CONTRACT NUMBER...length adaptation, and 50% via carrier sense threshold adaptation. 15. SUBJECT TERMS 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT

  10. Stereo Pair, Lake Palanskoye Landslide, Kamchatka Peninsula, Russia

    NASA Technical Reports Server (NTRS)

    2000-01-01

    The Lake Palanskoye in northern Kamchatka was formed when a large landslide disrupted the drainage pattern, forming a natural dam. The area is volcanically and tectonically active and it is likely that the landslide -- which covers about 80 square kilometers (30 square miles) --was triggered by an earthquake sometime in the past 10,000 years. The source area of the landslide is the ridge between the two bright rocky features to the lower left of the lake. In 3-D, the steep topographic scar at the head of the slide and the broad expanse of hummocky landslide debris that covers the valley just below the lake are visible. This Landsat/SRTM stereoscopic view is an enhanced true color image: Vegetation appears green, rocks are brownish, snow is white and water (such as the lake) appears very dark.

    This stereoscopic image pair was generated using topographic data from SRTM combined with a Landsat 7 satellite image collected the previous summer. The topography data were used to create two differing perspectives of a single image -- one for each eye. Depending on its elevation, each point in the image was shifted slightly. When stereoscopically merged, the result is a vertically exaggerated view of the Earth's surface in its full three dimensions.

    Landsat satellites have provided visible light and infrared images of the Earth continuously since 1972. SRTM topographic data match the 30 meter(99 foot) spatial resolution of most Landsat images and will provide a valuable complement for studying the historic and growing Landsat data archive. The Landsat 7 Thematic Mapper image used here was provided to the SRTM project by the United States Geological Survey, Earth Resources Observation Systems (EROS) Data Center, Sioux Falls, South Dakota.

    The Shuttle Radar Topography Mission (SRTM), launched on February 11, 2000, used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space

  11. Anaglyph, Lake Palanskoye Landslide, Kamchatka Peninsula, Russia

    NASA Technical Reports Server (NTRS)

    2000-01-01

    The Lake Palanskoye in northern Kamchatka was formed when a large landslide disrupted the drainage pattern, forming a natural dam. The area is volcanically and tectonically active and it is likely that the landslide -- which covers about 80 square kilometers (30 square miles) --was triggered by an earthquake sometime in the past 10,000 years. The source area of the landslide is the ridge to the upper left of the lake. The steep topographic scar at the head of the slide and the broad expanse of hummocky landslide debris that covers the valley to the left of the lake are visible in 3D.

    This anaglyph was generated by first draping a Landsat Thematic Mapper near-infrared image over a topographic map from the Shuttle Radar Topography Mission, then using the topographic data to create two differing perspectives, one for each eye. When viewed through special glasses, the result is a vertically exaggerated view of the Earth's surface in its full three dimensions. Anaglyph glasses cover the left eye with a red filter and cover the right eye with a blue filter.

    Landsat satellites have provided visible light and infrared images of the Earth continuously since 1972. SRTM topographic data match the 30 meter (99 foot) spatial resolution of most Landsat images and will provide a valuable complement for studying the historic and growing Landsat data archive. The Landsat 7 Thematic Mapper image used here was provided to the SRTM project by the United States Geological Survey, Earth Resources Observation Systems (EROS) Data Center, Sioux Falls, South Dakota.

    The Shuttle Radar Topography Mission (SRTM), launched on February 11, 2000, used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect three-dimensional measurements of the Earth's surface on its 11-day mission. To collect the 3-D data, engineers added a 60-meter

  12. The spatial range of peripheral collinear facilitation

    PubMed Central

    Maniglia, Marcello; Pavan, Andrea; Aedo-Jury, Felipe; Trotter, Yves

    2015-01-01

    Contrast detection thresholds for a central Gabor patch (target) can be modulated by the presence of co-oriented and collinear high contrast Gabors flankers. In foveal vision collinear facilitation can be observed for target-to-flankers relative distances beyond two times the wavelength (λ) of the Gabor’s carrier, while for shorter relative distances (<2λ) there is suppression. These modulatory influences seem to disappear after 12λ. In this study, we measured contrast detection thresholds for different spatial frequencies (1, 4 and 6 cpd) and target-to-flankers relative distances ranging from 6 to 16λ, but with collinear configurations presented in near periphery at 4° of eccentricity. Results showed that in near periphery collinear facilitation extends beyond 12λ for the higher spatial frequencies tested (4 and 6 cpd), while it decays already at 10λ for the lowest spatial frequency used (i.e., 1 cpd). In addition, we found that increasing the spatial frequency the peak of collinear facilitation shifts towards larger target-to-flankers relative distances (expressed as multiples of the stimulus wavelength), an effect never reported neither for near peripheral nor for central vision. The results suggest that the peak and the spatial extent of collinear facilitation in near periphery depend on the spatial frequency of the stimuli used. PMID:26502834

  13. Multivariate semiparametric spatial methods for imaging data.

    PubMed

    Chen, Huaihou; Cao, Guanqun; Cohen, Ronald A

    2017-04-01

    Univariate semiparametric methods are often used in modeling nonlinear age trajectories for imaging data, which may result in efficiency loss and lower power for identifying important age-related effects that exist in the data. As observed in multiple neuroimaging studies, age trajectories show similar nonlinear patterns for the left and right corresponding regions and for the different parts of a big organ such as the corpus callosum. To incorporate the spatial similarity information without assuming spatial smoothness, we propose a multivariate semiparametric regression model with a spatial similarity penalty, which constrains the variation of the age trajectories among similar regions. The proposed method is applicable to both cross-sectional and longitudinal region-level imaging data. We show the asymptotic rates for the bias and covariance functions of the proposed estimator and its asymptotic normality. Our simulation studies demonstrate that by borrowing information from similar regions, the proposed spatial similarity method improves the efficiency remarkably. We apply the proposed method to two neuroimaging data examples. The results reveal that accounting for the spatial similarity leads to more accurate estimators and better functional clustering results for visualizing brain atrophy pattern.Functional clustering; Longitudinal magnetic resonance imaging (MRI); Penalized B-splines; Region of interest (ROI); Spatial penalty.

  14. [Brain mapping in verbal and spatial thinking].

    PubMed

    Ivanitskiĭ, A M; Portnova, G V; Martynova, O V; Maĭorova, L A; Fedina, O N; Petrushevskiĭ, A G

    2013-01-01

    The goal of this study was to describe the topography of the active cortical areas and subcortical structuresin verbal and spatial thinking. The method of functional magnetic resonance imaging (fMRI) was used. 18 right-handed subjects participated in the study. Four types of tasks were presented: two experimental tasks--verbal (anagram) and spatial (search for a piece to complement a square), and two types of control tasks (written words and a spatial task, where all the pieces are identical). In solving verbal tasks the greater volume of activation was observed in the left hemisphere involving Broca's area, while the right middle frontal gyrus was activated in solving the spatial tasks. For occipital region an activation of the visual field 18 was more explicitin solving spatial problems, while the solution of anagrams caused an activation of the field 19 associated with higher levels of visual processing. The cerebellum was active bilaterally in both tasks with predominance in the second. The obtained fMRI data indicate that the verbal and spatial types of thinking are provided by an activation of narrow specific sets of brain structures, while the previous electrophysiological studies indicate the distributed nature of the brain processes in thinking. Combining these two approaches, it can be concluded that cognitive functions are supported by the systemic brain processes with a distinct location of the particular salient structures.

  15. Focal plane scanner with reciprocating spatial window

    NASA Technical Reports Server (NTRS)

    Mao, Chengye (Inventor)

    2000-01-01

    A focal plane scanner having a front objective lens, a spatial window for selectively passing a portion of the image therethrough, and a CCD array for receiving the passed portion of the image. All embodiments have a common feature whereby the spatial window and CCD array are mounted for simultaneous relative reciprocating movement with respect to the front objective lens, and the spatial window is mounted within the focal plane of the front objective. In a first embodiment, the spatial window is a slit and the CCD array is one-dimensional, and successive rows of the image in the focal plane of the front objective lens are passed to the CCD array by an image relay lens interposed between the slit and the CCD array. In a second embodiment, the spatial window is a slit, the CCD array is two-dimensional, and a prism-grating-prism optical spectrometer is interposed between the slit and the CCD array so as to cause the scanned row to be split into a plurality of spectral separations onto the CCD array. In a third embodiment, the CCD array is two-dimensional and the spatial window is a rectangular linear variable filter (LVF) window, so as to cause the scanned rows impinging on the LVF to be bandpass filtered into spectral components onto the CCD array through an image relay lens interposed between the LVF and the CCD array.

  16. Computing spatial information from Fourier coefficient distributions.

    PubMed

    Heinz, William F; Werbin, Jeffrey L; Lattman, Eaton; Hoh, Jan H

    2011-05-01

    The spatial relationships between molecules can be quantified in terms of information. In the case of membranes, the spatial organization of molecules in a bilayer is closely related to biophysically and biologically important properties. Here, we present an approach to computing spatial information based on Fourier coefficient distributions. The Fourier transform (FT) of an image contains a complete description of the image, and the values of the FT coefficients are uniquely associated with that image. For an image where the distribution of pixels is uncorrelated, the FT coefficients are normally distributed and uncorrelated. Further, the probability distribution for the FT coefficients of such an image can readily be obtained by Parseval's theorem. We take advantage of these properties to compute the spatial information in an image by determining the probability of each coefficient (both real and imaginary parts) in the FT, then using the Shannon formalism to calculate information. By using the probability distribution obtained from Parseval's theorem, an effective distance from the uncorrelated or most uncertain case is obtained. The resulting quantity is an information computed in k-space (kSI). This approach provides a robust, facile and highly flexible framework for quantifying spatial information in images and other types of data (of arbitrary dimensions). The kSI metric is tested on a 2D Ising model, frequently used as a model for lipid bilayer; and the temperature-dependent phase transition is accurately determined from the spatial information in configurations of the system.

  17. Spatial priming in ecologically relevant reference frames.

    PubMed

    Tower-Richardi, Sarah M; Leber, Andrew B; Golomb, Julie D

    2016-01-01

    In recent years, researchers have observed many phenomena demonstrating how the visual system exploits spatial regularities in the environment in order to benefit behavior. In this paper, we question whether spatial priming can be considered one such phenomenon. Spatial priming is defined as a response time facilitation to a visual search target when its spatial position has been repeated in recent trials (Maljkovic & Nakayama, 1996, Perception & Psychophysics, 58, 977-991). Does this priming serve a behaviorally adaptive role or is it merely a byproduct of ongoing visual processing? Critically, an adaptive priming mechanism must actively transform visual inputs from native retinotopic (eye-centered) coordinates into ecologically relevant coordinates, e.g., spatiotopic (world-centered) and/or object-centered. In Experiment 1, we tested this hypothesis by having participants move their eyes between trials, which dissociated retinotopic and spatiotopic frames of reference. Results showed only weak retinotopic priming, but robust spatiotopic priming. The second experiment again had participants move their eyes between trials but also manipulated the placement of a grouped array of display objects from trial to trial. This allowed us to measure not just retinotopic and spatiotopic priming, but object-centered priming as well. Results from this experiment did not yield retinotopic priming but showed robust spatiotopic and object-centered priming. These findings demonstrate that spatial priming operates within ecologically relevant coordinate systems, and the findings support the notion that spatial priming serves an adaptive role in human behavior.

  18. Development of an Everyday Spatial Behavioral Questionnaire.

    PubMed

    Eliot, John; Czarnolewski, Mark Y

    2007-07-01

    The authors developed a 12-category, 116-item critical incident questionnaire of spatial behavior. The authors administered the Everyday Spatial Behavioral Questionnaire (ESBQ) to volunteer undergraduates (114 women, and 31 men) and tests of spatial ability to establish both the reliability and construct validity of the instrument. The authors found that Cronbach's alpha across the subscale scores was .92, and that 8 of the 12 subscales had alphas of .70 or greater. The authors found validity of the ESBQ through canonical correlation analysis. Specifically, spatial tests, gender, and age variables, jointly with the ESBQ subscales, identified 2 apparent continua of spatial skills. The authors labeled the first continuum movement through space (from moving a vehicle at one end of the continuum, to moving one's own body through space at the other end of the continuum). The authors labeled the second identified continuum drawing/perceiving perspective/path finding, and it appeared to represent a continuum of 3-dimensional visualization or redirection. Another suggested label was dimensional discernment. Thus, the ESBQ is a first step toward identifying new ways to think about and quantify people's spatial experience.

  19. The spatial patterns of directional phenotypic selection.

    PubMed

    Siepielski, Adam M; Gotanda, Kiyoko M; Morrissey, Michael B; Diamond, Sarah E; DiBattista, Joseph D; Carlson, Stephanie M

    2013-11-01

    Local adaptation, adaptive population divergence and speciation are often expected to result from populations evolving in response to spatial variation in selection. Yet, we lack a comprehensive understanding of the major features that characterise the spatial patterns of selection, namely the extent of variation among populations in the strength and direction of selection. Here, we analyse a data set of spatially replicated studies of directional phenotypic selection from natural populations. The data set includes 60 studies, consisting of 3937 estimates of selection across an average of five populations. We performed meta-analyses to explore features characterising spatial variation in directional selection. We found that selection tends to vary mainly in strength and less in direction among populations. Although differences in the direction of selection occur among populations they do so where selection is often weakest, which may limit the potential for ongoing adaptive population divergence. Overall, we also found that spatial variation in selection appears comparable to temporal (annual) variation in selection within populations; however, several deficiencies in available data currently complicate this comparison. We discuss future research needs to further advance our understanding of spatial variation in selection.

  20. Exogenous spatial attention decreases audiovisual integration.

    PubMed

    Van der Stoep, N; Van der Stigchel, S; Nijboer, T C W

    2015-02-01

    Multisensory integration (MSI) and spatial attention are both mechanisms through which the processing of sensory information can be facilitated. Studies on the interaction between spatial attention and MSI have mainly focused on the interaction between endogenous spatial attention and MSI. Most of these studies have shown that endogenously attending a multisensory target enhances MSI. It is currently unclear, however, whether and how exogenous spatial attention and MSI interact. In the current study, we investigated the interaction between these two important bottom-up processes in two experiments. In Experiment 1 the target location was task-relevant, and in Experiment 2 the target location was task-irrelevant. Valid or invalid exogenous auditory cues were presented before the onset of unimodal auditory, unimodal visual, and audiovisual targets. We observed reliable cueing effects and multisensory response enhancement in both experiments. To examine whether audiovisual integration was influenced by exogenous spatial attention, the amount of race model violation was compared between exogenously attended and unattended targets. In both Experiment 1 and Experiment 2, a decrease in MSI was observed when audiovisual targets were exogenously attended, compared to when they were not. The interaction between exogenous attention and MSI was less pronounced in Experiment 2. Therefore, our results indicate that exogenous attention diminishes MSI when spatial orienting is relevant. The results are discussed in terms of models of multisensory integration and attention.

  1. Self-locomotion and spatial language and spatial cognition: insights from typical and atypical development.

    PubMed

    Oudgenoeg-Paz, Ora; Rivière, James

    2014-01-01

    Various studies have shown that occurrence of locomotion in infancy is correlated with the development of spatial cognitive competencies. Recent evidence suggests that locomotor experience might also be important for the development of spatial language. Together these findings suggest that locomotor experience might play a crucial role in the development of linguistic-cognitive spatial skills. However, some studies indicate that, despite their total deprivation of locomotor experience, young children with spinal muscular atrophy (SMA) have the capacity to acquire and use rich spatial representations including good spatial language. Nonetheless, we have to be cautious about what the striking performances displayed by SMA children can reveal on the link between motor and spatial development, as the dynamics of brain development in atypically developing children are different from typically developing children.

  2. Self-locomotion and spatial language and spatial cognition: insights from typical and atypical development

    PubMed Central

    Oudgenoeg-Paz, Ora; Rivière, James

    2014-01-01

    Various studies have shown that occurrence of locomotion in infancy is correlated with the development of spatial cognitive competencies. Recent evidence suggests that locomotor experience might also be important for the development of spatial language. Together these findings suggest that locomotor experience might play a crucial role in the development of linguistic-cognitive spatial skills. However, some studies indicate that, despite their total deprivation of locomotor experience, young children with spinal muscular atrophy (SMA) have the capacity to acquire and use rich spatial representations including good spatial language. Nonetheless, we have to be cautious about what the striking performances displayed by SMA children can reveal on the link between motor and spatial development, as the dynamics of brain development in atypically developing children are different from typically developing children. PMID:24917836

  3. Spatial vs. Nonspatial Reasoning Ability in Chronic Schizophrenics

    ERIC Educational Resources Information Center

    Hartlage, Lawrence C.; Garber, Judy

    1976-01-01

    Compares spatial with nonspatial reasoning ability within the same patients to determine whether spatial reasoning deficits in schizophrenics are specific to spatial types of tasks or are indicative of generalized reasoning difficulties. (Author/RK)

  4. Spatial modeling of the schistosomiasis mansoni in Minas Gerais State, Brazil using spatial regression.

    PubMed

    Fonseca, F; Freitas, C; Dutra, L; Guimarães, R; Carvalho, O

    2014-05-01

    Schistosomiasis is a transmissible parasitic disease caused by the etiologic agent Schistosoma mansoni, whose intermediate hosts are snails of the genus Biomphalaria. The main goal of this paper is to estimate the prevalence of schistosomiasis in Minas Gerais State in Brazil using spatial disease information derived from the state transportation network of roads and rivers. The spatial information was incorporated in two ways: by introducing new variables that carry spatial neighborhood information and by using spatial regression models. Climate, socioeconomic and environmental variables were also used as co-variables to build models and use them to estimate a risk map for the whole state of Minas Gerais. The results show that the models constructed from the spatial regression produced a better fit, providing smaller root mean square error (RMSE) values. When no spatial information was used, the RMSE for the whole state of Minas Gerais reached 9.5%; with spatial regression, the RMSE reaches 8.8% (when the new variables are added to the model) and 8.5% (with the use of spatial regression). Variables representing vegetation, temperature, precipitation, topography, sanitation and human development indexes were important in explaining the spread of disease and identified certain conditions that are favorable for disease development. The use of spatial regression for the network of roads and rivers produced meaningful results for health management procedures and directing activities, enabling better detection of disease risk areas.

  5. Compatible Spatial Discretizations for Partial Differential Equations

    SciTech Connect

    Arnold, Douglas, N, ed.

    2004-11-25

    From May 11--15, 2004, the Institute for Mathematics and its Applications held a hot topics workshop on Compatible Spatial Discretizations for Partial Differential Equations. The numerical solution of partial differential equations (PDE) is a fundamental task in science and engineering. The goal of the workshop was to bring together a spectrum of scientists at the forefront of the research in the numerical solution of PDEs to discuss compatible spatial discretizations. We define compatible spatial discretizations as those that inherit or mimic fundamental properties of the PDE such as topology, conservation, symmetries, and positivity structures and maximum principles. A wide variety of discretization methods applied across a wide range of scientific and engineering applications have been designed to or found to inherit or mimic intrinsic spatial structure and reproduce fundamental properties of the solution of the continuous PDE model at the finite dimensional level. A profusion of such methods and concepts relevant to understanding them have been developed and explored: mixed finite element methods, mimetic finite differences, support operator methods, control volume methods, discrete differential forms, Whitney forms, conservative differencing, discrete Hodge operators, discrete Helmholtz decomposition, finite integration techniques, staggered grid and dual grid methods, etc. This workshop seeks to foster communication among the diverse groups of researchers designing, applying, and studying such methods as well as researchers involved in practical solution of large scale problems that may benefit from advancements in such discretizations; to help elucidate the relations between the different methods and concepts; and to generally advance our understanding in the area of compatible spatial discretization methods for PDE. Particular points of emphasis included: + Identification of intrinsic properties of PDE models that are critical for the fidelity of numerical

  6. Turning the tables: language and spatial reasoning.

    PubMed

    Li, Peggy; Gleitman, Lila

    2002-04-01

    This paper investigates possible influences of the lexical resources of individual languages on the spatial organization and reasoning styles of their users. That there are such powerful and pervasive influences of language on thought is the thesis of the Whorf-Sapir linguistic relativity hypothesis which, after a lengthy period in intellectual limbo, has recently returned to prominence in the anthropological, linguistic, and psycholinguistic literatures. Our point of departure is an influential group of cross-linguistic studies that appear to show that spatial reasoning is strongly affected by the spatial lexicon in everyday use in a community (e.g. Brown, P., & Levinson, S. C. (1993). Linguistic and nonlinguistic coding of spatial arrays: explorations in Mayan cognition (Working Paper No. 24). Nijmegen: Cognitive Anthropology Research Group, Max Planck Institute for Psycholinguistics; Cognitive Linguistics 6 (1995) 33). Specifically, certain groups customarily use an externally referenced spatial-coordinate system to refer to nearby directions and positions ("to the north") whereas English speakers usually employ a viewer-perspective system ("to the left"). Prior findings and interpretations have been to the effect that users of these two types of spatial system solve rotation problems in different ways, reasoning strategies imposed by habitual use of the language-particular lexicons themselves. The present studies reproduce these different problem-solving strategies in speakers of a single language (English) by manipulating landmark cues, suggesting that language itself may not be the key causal factor in choice of spatial perspective. Prior evidence on rotation problem solution from infants (e.g. Acredolo, L.P. (1979). Laboratory versus home: the effect of environment on the 9-month-old infant's choice of spatial reference system. Developmental Psychology, 15 (6), 666-667) and from laboratory animals (e.g. Restle, F. (1975). Discrimination of cues in mazes: a

  7. Methodologic Issues and Approaches to Spatial Epidemiology

    PubMed Central

    Beale, Linda; Abellan, Juan Jose; Hodgson, Susan; Jarup, Lars

    2008-01-01

    Spatial epidemiology is increasingly being used to assess health risks associated with environmental hazards. Risk patterns tend to have both a temporal and a spatial component; thus, spatial epidemiology must combine methods from epidemiology, statistics, and geographic information science. Recent statistical advances in spatial epidemiology include the use of smoothing in risk maps to create an interpretable risk surface, the extension of spatial models to incorporate the time dimension, and the combination of individual- and area-level information. Advances in geographic information systems and the growing availability of modeling packages have led to an improvement in exposure assessment. Techniques drawn from geographic information science are being developed to enable the visualization of uncertainty and ensure more meaningful inferences are made from data. When public health concerns related to the environment arise, it is essential to address such anxieties appropriately and in a timely manner. Tools designed to facilitate the investigation process are being developed, although the availability of complete and clean health data, and appropriate exposure data often remain limiting factors. PMID:18709139

  8. Instrumentation For Detector Spectral / Spatial Uniformity Measurements

    NASA Astrophysics Data System (ADS)

    Craft, Ronald W.; Bronson, Robert M.

    1989-09-01

    The information presented in this report describes an instrument which is used for precision measurements of detector spectral response and spatial response. Emphasis will be placed on detector spatial uniformity measurements. To allow spatial uniformity testing at selected wavelengths, an instrument was designed by applying existing spectral response instrumentation technology with the addition of special exit optics, a dual axis motorized positioning table, and supporting software. Supporting components consisted of a computer controlled radiometer and a monochromator with a high intensity light source attached. Spectral response is determined by measuring the wavelength response photosensitivity of a stationary specimen to the irradiance of a calibrated monochromatic light source over the wavelength range of interest at evenly spaced intervals. Data is presented in a pictorial format by graphing the RESPONSE versus the WAVELENGTH. Detector spatial response is determined by measuring the variation in photosensitivity over the surface of the test detector by moving the detector in an X,Y grid at evenly spaced intervals under a small monochromatic spot of light. Several versions of the instrument were built and test results are provided which represent data from the spatial uniformity testing of Ge, PbS, and PbSe detectors. Data acquired is presented as a 3-Dimensional surface map by plotting the RESPONSE versus the X POSITION versus the Y POSITION.

  9. Gender differences in multitasking reflect spatial ability.

    PubMed

    Mäntylä, Timo

    2013-04-01

    Demands involving the scheduling and interleaving of multiple activities have become increasingly prevalent, especially for women in both their paid and unpaid work hours. Despite the ubiquity of everyday requirements to multitask, individual and gender-related differences in multitasking have gained minimal attention in past research. In two experiments, participants completed a multitasking session with four gender-fair monitoring tasks and separate tasks measuring executive functioning (working memory updating) and spatial ability (mental rotation). In both experiments, males outperformed females in monitoring accuracy. Individual differences in executive functioning and spatial ability were independent predictors of monitoring accuracy, but only spatial ability mediated gender differences in multitasking. Menstrual changes accentuated these effects, such that gender differences in multitasking (and spatial ability) were eliminated between males and females who were in the menstrual phase of the menstrual cycle but not between males and females who were in the luteal phase. These findings suggest that multitasking involves spatiotemporal task coordination and that gender differences in multiple-task performance reflect differences in spatial ability.

  10. The development of spatial frequency discrimination.

    PubMed

    Patel, Ashna; Maurer, Daphne; Lewis, Terri L

    2010-12-31

    We compared thresholds for discriminating spatial frequency for children aged 5, 7, and 9 years, and adults at two baseline spatial frequencies (1 and 3 cpd). In Experiment 1, the minimum change from baseline necessary to detect a change in spatial frequency from either baseline decreased with age from 34% in 5-year-olds to 11% in 7-year-olds, 8% in 9-year-olds, and 6% in adults. The data were best fit by an exponential function reflecting the rapid improvement in thresholds between 5 and 7 years of age and more gradual improvement thereafter (r(2) = 0.50, p < 0.0001). In Experiment 2, 5-year-olds' thresholds were higher than those of adults, even when memory demands were eliminated by presenting the two spatial frequencies side by side for an unlimited time. The pattern of development for sensitivity to spatial frequency (this study) resembles those for the development of sensitivity to orientation (T. L. Lewis, S. E. Chong, & D. Maurer, 2009) and contrast (D. Ellemberg, T. L. Lewis, C. H. Lui, & D. Maurer, 1999). The similar patterns are consistent with theories of common underlying mechanisms in primary visual cortex (A. Vincent & D. Regan, 1995; W. Zhu, M. Shelley, & R. Shapley, 2008) and suggest that those mechanisms continue to develop throughout childhood.

  11. Spatial turnover in the global avifauna.

    PubMed

    Gaston, Kevin J; Davies, Richard G; Orme, C David L; Olson, Valerie A; Thomas, Gavin H; Ding, Tzung-Su; Rasmussen, Pamela C; Lennon, Jack J; Bennett, Peter M; Owens, Ian P F; Blackburn, Tim M

    2007-07-07

    Despite its wide implications for many ecological issues, the global pattern of spatial turnover in the occurrence of species has been little studied, unlike the global pattern of species richness. Here, using a database on the breeding distributions of birds, we present the first global maps of variation in spatial turnover for an entire taxonomic class, a pattern that has to date remained largely a matter of conjecture, based on theoretical expectations and extrapolation of inconsistent patterns from different biogeographic realms. We use these maps to test four predictions from niche theory as to the form that this variation should take, namely that turnover should increase with species richness, towards lower latitudes, and with the steepness of environmental gradients and that variation in turnover is determined principally by rare (restricted) species. Contrary to prediction, we show that turnover is high both in areas of extremely low and high species richness, does not increase strongly towards the tropics, and is related both to average environmental conditions and spatial variation in those conditions. These results are closely associated with a further important and novel finding, namely that global patterns of spatial turnover are driven principally by widespread species rather than the restricted ones. This complements recent demonstrations that spatial patterns of species richness are also driven principally by widespread species, and thus provides an important contribution towards a unified model of how terrestrial biodiversity varies both within and between the Earth's major land masses.

  12. The spatial structure of cell signaling systems

    PubMed Central

    Nussinov, Ruth

    2013-01-01

    The spatial structure of the cell is highly organized at all levels: from small complexes and assemblies, to local nano- and micro-clusters, to global, micrometer scales across and between cells. We suggest that this multiscale spatial cell organization also organizes signaling and coordinates cellular behavior. We propose a new view of the spatial structure of cell signaling systems. This new view describes cell signaling in terms of dynamic allosteric interactions within and among distinct, spatially organized transient clusters. The clusters vary over time and space and are on length scales from nanometers to micrometers. When considered across these length-scales, primary factors in the spatial organization are cell membrane domains and the actin cytoskeleton, both also highly dynamic. A key challenge is to understand the interplay across these multiple scales, link it to the physicochemical basis of the conformational behavior of single molecules, and ultimately relate it to cellular function. Overall, our premise is that at these scales, cell signaling should be thought of not primarily as a sequence of diffusion-controlled molecular collisions, but instead transient, allostery-driven cluster re-forming interactions. PMID:23913102

  13. Spatial Competition: Roughening of an Experimental Interface

    PubMed Central

    Allstadt, Andrew J.; Newman, Jonathan A.; Walter, Jonathan A.; Korniss, G.; Caraco, Thomas

    2016-01-01

    Limited dispersal distance generates spatial aggregation. Intraspecific interactions are then concentrated within clusters, and between-species interactions occur near cluster boundaries. Spread of a locally dispersing invader can become motion of an interface between the invading and resident species, and spatial competition will produce variation in the extent of invasive advance along the interface. Kinetic roughening theory offers a framework for quantifying the development of these fluctuations, which may structure the interface as a self-affine fractal, and so induce a series of temporal and spatial scaling relationships. For most clonal plants, advance should become spatially correlated along the interface, and width of the interface (where invader and resident compete directly) should increase as a power function of time. Once roughening equilibrates, interface width and the relative location of the most advanced invader should each scale with interface length. We tested these predictions by letting white clover (Trifolium repens) invade ryegrass (Lolium perenne). The spatial correlation of clover growth developed as anticipated by kinetic roughening theory, and both interface width and the most advanced invader’s lead scaled with front length. However, the scaling exponents differed from those predicted by recent simulation studies, likely due to clover’s growth morphology. PMID:27465518

  14. Spatial Relation Predicates in Topographic Feature Semantics

    USGS Publications Warehouse

    Varanka, Dalia E.; Caro, Holly K.

    2013-01-01

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

  15. Developmental dyslexia and spatial relationship perception.

    PubMed

    Aleci, Carlo; Piana, Giulio; Piccoli, Marzia; Bertolini, Marco

    2012-04-01

    According to wide literature, a global impairment in the temporal and spatial domains as well as an increased crowding effect is common of dyslexics. The aim of the study was to evaluate if such subjects suffer from a more general impairment of spatial relationship perception (SRP) and in particular from anomalous spatial relationship anisotropy (SRA) thus accounting both for their global perceptual distortions and abnormal crowding. SRP of 39 young disabled readers and 23 normal subjects were measured by a specifically designed psychophysical technique based on circular and elliptical target recognitions. A general impairment of SRP characterized by increased horizontal/vertical anisotropy was found in the dyslexic sample compared to the controls. In the second part of the experiment, reading efficiency and reading time were measured by MNREAD(©) reading cards in standard conditions and after increasing horizontal spatial extension of the sentence by different values. We suppose this modification could well compensate the abnormal anisotropy found in dyslexics. Data obtained in the two groups were compared. A strong correlation between reading efficiency (a parameter we have specifically devised) and horizontal spatial text relationship values were present in the patients (r=.87, p<.01), but not in the controls. The same was found taking into consideration mean reading time (r=-.82, p<.01). We therefore gather that an alteration of SRP, characterized by an increased anisotropy may be involved in developmental dyslexia.

  16. Critical bands in cat spatial vision.

    PubMed Central

    Blake, R; Martens, W

    1981-01-01

    1. The ability of cats to detect sinusoidal grating patterns superimposed on one-dimensional visual noise was assessed using behavioural methods. 2. The magnitude of elevation in contrast threshold due to noise increased monotonically within limits with increasing noise contrast. 3. Visual noise was filtered using various techniques (band-reject, low-pass, high-pass and band-pass noise); filtered noise resulted in threshold elevation only when it contained frequencies similar to the test frequency. 4. In all cases the masking functions indicated that the band widths of the channels mediating detection ranged from +/- 0.50 to +/- 0.75 octaves across three spatial frequencies and that the channel sensitive to low spatial frequencies was asymmetrical in its tuning. 5. The spatial properties of these psychophysical detecting channels closely resemble the spatial frequency selectivity exhibited by some cat cortical neurones, both in the general narrowness of tuning and the asymmetry in tuning at lower, but not higher, spatial frequencies. PMID:7310689

  17. Indoor Spatial Updating With Impaired Vision

    PubMed Central

    Legge, Gordon E.; Granquist, Christina; Baek, Yihwa; Gage, Rachel

    2016-01-01

    Purpose Spatial updating is the ability to keep track of position and orientation while moving through an environment. We asked how normally sighted and visually impaired subjects compare in spatial updating and in estimating room dimensions. Methods Groups of 32 normally sighted, 16 low-vision, and 16 blind subjects estimated the dimensions of six rectangular rooms. Updating was assessed by guiding the subjects along three-segment paths in the rooms. At the end of each path, they estimated the distance and direction to the starting location, and to a designated target. Spatial updating was tested in five conditions ranging from free viewing to full auditory and visual deprivation. Results The normally sighted and low-vision groups did not differ in their accuracy for judging room dimensions. Correlations between estimated size and physical size were high. Accuracy of low-vision performance was not correlated with acuity, contrast sensitivity, or field status. Accuracy was lower for the blind subjects. The three groups were very similar in spatial-updating performance, and exhibited only weak dependence on the nature of the viewing conditions. Conclusions People with a wide range of low-vision conditions are able to judge room dimensions as accurately as people with normal vision. Blind subjects have difficulty in judging the dimensions of quiet rooms, but some information is available from echolocation. Vision status has little impact on performance in simple spatial updating; proprioceptive and vestibular cues are sufficient. PMID:27978556

  18. Temporal dynamics of divided spatial attention.

    PubMed

    Itthipuripat, Sirawaj; Garcia, Javier O; Serences, John T

    2013-05-01

    In naturalistic settings, observers often have to monitor multiple objects dispersed throughout the visual scene. However, the degree to which spatial attention can be divided across spatially noncontiguous objects has long been debated, particularly when those objects are in close proximity. Moreover, the temporal dynamics of divided attention are unclear: is the process of dividing spatial attention gradual and continuous, or does it onset in a discrete manner? To address these issues, we recorded steady-state visual evoked potentials (SSVEPs) as subjects covertly monitored two flickering targets while ignoring an intervening distractor that flickered at a different frequency. All three stimuli were clustered within either the lower left or the lower right quadrant, and our dependent measure was SSVEP power at the target and distractor frequencies measured over time. In two experiments, we observed a temporally discrete increase in power for target- vs. distractor-evoked SSVEPs extending from ∼350 to 150 ms prior to correct (but not incorrect) responses. The divergence in SSVEP power immediately prior to a correct response suggests that spatial attention can be divided across noncontiguous locations, even when the targets are closely spaced within a single quadrant. In addition, the division of spatial attention appears to be relatively discrete, as opposed to slow and continuous. Finally, the predictive relationship between SSVEP power and behavior demonstrates that these neurophysiological measures of divided attention are meaningfully related to cognitive function.

  19. Stream segregation with high spatial acuity

    PubMed Central

    Middlebrooks, John C.; Onsan, Zekiye A.

    2012-01-01

    Spatial hearing is widely regarded as helpful in recognizing a sound amid other competing sounds. It is a matter of debate, however, whether spatial cues contribute to “stream segregation,” which refers to the specific task of assigning multiple interleaved sequences of sounds to their respective sources. The present study employed “rhythmic masking release” as a measure of the spatial acuity of stream segregation. Listeners discriminated between rhythms of noise-burst sequences presented from free-field targets in the presence of interleaved maskers that varied in location. For broadband sounds in the horizontal plane, target-masker separations of ≥8° permitted rhythm discrimination with d′ ≥ 1; in some cases, such thresholds approached listeners’ minimum audible angles. Thresholds were the same for low-frequency sounds but were substantially wider for high-frequency sounds, suggesting that interaural delays provided higher spatial acuity in this task than did interaural level differences. In the vertical midline, performance varied dramatically as a function of noise-burst duration with median thresholds ranging from >30° for 10-ms bursts to 7.1° for 40-ms bursts. A marked dissociation between minimum audible angles and masking release thresholds across the various pass-band and burst-duration conditions suggests that location discrimination and spatial stream segregation are mediated by distinct auditory mechanisms. PMID:23231120

  20. Spatial Competition: Roughening of an Experimental Interface

    NASA Astrophysics Data System (ADS)

    Allstadt, Andrew J.; Newman, Jonathan A.; Walter, Jonathan A.; Korniss, G.; Caraco, Thomas

    2016-07-01

    Limited dispersal distance generates spatial aggregation. Intraspecific interactions are then concentrated within clusters, and between-species interactions occur near cluster boundaries. Spread of a locally dispersing invader can become motion of an interface between the invading and resident species, and spatial competition will produce variation in the extent of invasive advance along the interface. Kinetic roughening theory offers a framework for quantifying the development of these fluctuations, which may structure the interface as a self-affine fractal, and so induce a series of temporal and spatial scaling relationships. For most clonal plants, advance should become spatially correlated along the interface, and width of the interface (where invader and resident compete directly) should increase as a power function of time. Once roughening equilibrates, interface width and the relative location of the most advanced invader should each scale with interface length. We tested these predictions by letting white clover (Trifolium repens) invade ryegrass (Lolium perenne). The spatial correlation of clover growth developed as anticipated by kinetic roughening theory, and both interface width and the most advanced invader’s lead scaled with front length. However, the scaling exponents differed from those predicted by recent simulation studies, likely due to clover’s growth morphology.

  1. Auditory Spatial Recalibration in Congenital Blind Individuals

    PubMed Central

    Finocchietti, Sara; Cappagli, Giulia; Gori, Monica

    2017-01-01

    Blind individuals show impairments for auditory spatial skills that require complex spatial representation of the environment. We suggest that this is partially due to the egocentric frame of reference used by blind individuals. Here we investigate the possibility of reducing the mentioned auditory spatial impairments with an audio-motor training. Our hypothesis is that the association between a motor command and the corresponding movement's sensory feedback can provide an allocentric frame of reference and consequently help blind individuals in understanding complex spatial relationships. Subjects were required to localize the end point of a moving sound before and after either 2-min of audio-motor training or a complete rest. During the training, subjects were asked to move their hand, and consequently the sound source, to freely explore the space around the setup and the body. Both congenital blind (N = 20) and blindfolded healthy controls (N = 28) participated in the study. Results suggest that the audio-motor training was effective in improving space perception of blind individuals. The improvement was not observed in those subjects that did not perform the training. This study demonstrates that it is possible to recalibrate the auditory spatial representation in congenital blind individuals with a short audio-motor training and provides new insights for rehabilitation protocols in blind people. PMID:28261053

  2. Culturally inconsistent spatial structure reduces learning.

    PubMed

    McCrink, Koleen; Shaki, Samuel

    2016-09-01

    Human adults tend to use a spatial continuum to organize any information they consider to be well-ordered, with a sense of initial and final position. The directionality of this spatial mapping is mediated by the culture of the subject, largely as a function of the prevailing reading and writing habits (for example, from left-to-right for English speakers or right-to-left for Hebrew speakers). In the current study, we tasked American and Israeli subjects with encoding and recalling a set of arbitrary pairings, consisting of frequently ordered stimuli (letters with shapes: Experiment 1) or infrequently ordered stimuli (color terms with shapes: Experiment 2), that were serially presented in a left-to-right, right-to-left, or central-only manner. The subjects were better at recalling information that contained ordinal stimuli if the spatial flow of presentation during encoding matched the dominant directionality of the subjects' culture, compared to information encoded in the non-dominant direction. This phenomenon did not extend to infrequently ordered stimuli (e.g., color terms). These findings suggest that adults implicitly harness spatial organization to support memory, and this harnessing process is culturally mediated in tandem with our spatial biases.

  3. Dengue Vectors and their Spatial Distribution

    PubMed Central

    Higa, Yukiko

    2011-01-01

    The distribution of dengue vectors, Ae. aegypti and Ae. albopictus, is affected by climatic factors. In addition, since their life cycles are well adapted to the human environment, environmental changes resulting from human activity such as urbanization exert a great impact on vector distribution. The different responses of Ae. aegypti and Ae albopictus to various environments result in a difference in spatial distribution along north-south and urban-rural gradients, and between the indoors and outdoors. In the north-south gradient, climate associated with survival is an important factor in spatial distribution. In the urban-rural gradient, different distribution reflects a difference in adult niches and is modified by geographic and human factors. The direct response of the two species to the environment around houses is related to different spatial distribution indoors and outdoors. Dengue viruses circulate mainly between human and vector mosquitoes, and the vector presence is a limiting factor of transmission. Therefore, spatial distribution of dengue vectors is a significant concern in the epidemiology of the disease. Current technologies such as GIS, satellite imagery and statistical models allow researchers to predict the spatial distribution of vectors in the changing environment. Although it is difficult to confirm the actual effect of environmental and climate changes on vector abundance and vector-borne diseases, environmental changes caused by humans and human behavioral changes due to climate change can be expected to exert an impact on dengue vectors. Longitudinal monitoring of dengue vectors and viruses is therefore necessary. PMID:22500133

  4. Spatial Inference for Distributed Remote Sensing Data

    NASA Astrophysics Data System (ADS)

    Braverman, A. J.; Katzfuss, M.; Nguyen, H.

    2014-12-01

    Remote sensing data are inherently spatial, and a substantial portion of their value for scientific analyses derives from the information they can provide about spatially dependent processes. Geophysical variables such as atmopsheric temperature, cloud properties, humidity, aerosols and carbon dioxide all exhibit spatial patterns, and satellite observations can help us learn about the physical mechanisms driving them. However, remote sensing observations are often noisy and incomplete, so inferring properties of true geophysical fields from them requires some care. These data can also be massive, which is both a blessing and a curse: using more data drives uncertainties down, but also drives costs up, particularly when data are stored on different computers or in different physical locations. In this talk I will discuss a methodology for spatial inference on massive, distributed data sets that does not require moving large volumes of data. The idea is based on a combination of ideas including modeling spatial covariance structures with low-rank covariance matrices, and distributed estimation in sensor or wireless networks.

  5. Integrating scientific guidance into marine spatial planning.

    PubMed

    Rassweiler, Andrew; Costello, Christopher; Hilborn, Ray; Siegel, David A

    2014-04-22

    Marine spatial planning (MSP), whereby areas of the ocean are zoned for different uses, has great potential to reduce or eliminate conflicts between competing management goals, but only if strategically applied. The recent literature overwhelmingly agrees that including stakeholders in these planning processes is critical to success; but, given the countless alternative ways even simple spatial regulations can be configured, how likely is it that a stakeholder-driven process will generate plans that deliver on the promise of MSP? Here, we use a spatially explicit, dynamic bioeconomic model to show that stakeholder-generated plans are doomed to fail in the absence of strong scientific guidance. While strategically placed spatial regulations can improve outcomes remarkably, the vast majority of possible plans fail to achieve this potential. Surprisingly, existing scientific rules of thumb do little to improve outcomes. Here, we develop an alternative approach in which models are used to identify efficient plans, which are then modified by stakeholders. Even if stakeholders alter these initial proposals considerably, results hugely outperform plans guided by scientific rules of thumb. Our results underscore the importance of spatially explicit dynamic models for the management of marine resources and illustrate how such models can be harmoniously integrated into a stakeholder-driven MSP process.

  6. Optimization techniques for integrating spatial data

    USGS Publications Warehouse

    Herzfeld, U.C.; Merriam, D.F.

    1995-01-01

    Two optimization techniques ta predict a spatial variable from any number of related spatial variables are presented. The applicability of the two different methods for petroleum-resource assessment is tested in a mature oil province of the Midcontinent (USA). The information on petroleum productivity, usually not directly accessible, is related indirectly to geological, geophysical, petrographical, and other observable data. This paper presents two approaches based on construction of a multivariate spatial model from the available data to determine a relationship for prediction. In the first approach, the variables are combined into a spatial model by an algebraic map-comparison/integration technique. Optimal weights for the map comparison function are determined by the Nelder-Mead downhill simplex algorithm in multidimensions. Geologic knowledge is necessary to provide a first guess of weights to start the automatization, because the solution is not unique. In the second approach, active set optimization for linear prediction of the target under positivity constraints is applied. Here, the procedure seems to select one variable from each data type (structure, isopachous, and petrophysical) eliminating data redundancy. Automating the determination of optimum combinations of different variables by applying optimization techniques is a valuable extension of the algebraic map-comparison/integration approach to analyzing spatial data. Because of the capability of handling multivariate data sets and partial retention of geographical information, the approaches can be useful in mineral-resource exploration. ?? 1995 International Association for Mathematical Geology.

  7. Michelson interferometer based spatial phase shift shearography.

    PubMed

    Xie, Xin; Yang, Lianxiang; Xu, Nan; Chen, Xu

    2013-06-10

    This paper presents a simple spatial phase shift shearography based on the Michelson interferometer. The Michelson interferometer based shearographic system has been widely utilized in industry as a practical nondestructive test tool. In the system, the Michelson interferometer is used as a shearing device to generate a shearing distance by tilting a small angle in one of the two mirrors. In fact, tilting the mirror in the Michelson interferometer also generates spatial frequency shift. Based on this feature, we introduce a simple Michelson interferometer based spatial phase shift shearography. The Fourier transform (FT) method is applied to separate the spectrum on the spatial frequency domain. The phase change due to the loading can be evaluated using a properly selected windowed inverse-FT. This system can generate a phase map of shearography by using only a single image. The effects of shearing angle, spatial resolution of couple charge device camera, and filter methods are discussed in detail. The theory and the experimental results are presented.

  8. Detecting spatial regimes in ecosystems | Science Inventory ...

    EPA Pesticide Factsheets

    Research on early warning indicators has generally focused on assessing temporal transitions with limited application of these methods to detecting spatial regimes. Traditional spatial boundary detection procedures that result in ecoregion maps are typically based on ecological potential (i.e. potential vegetation), and often fail to account for ongoing changes due to stressors such as land use change and climate change and their effects on plant and animal communities. We use Fisher information, an information theory based method, on both terrestrial and aquatic animal data (US Breeding Bird Survey and marine zooplankton) to identify ecological boundaries, and compare our results to traditional early warning indicators, conventional ecoregion maps, and multivariate analysis such as nMDS (non-metric Multidimensional Scaling) and cluster analysis. We successfully detect spatial regimes and transitions in both terrestrial and aquatic systems using Fisher information. Furthermore, Fisher information provided explicit spatial information about community change that is absent from other multivariate approaches. Our results suggest that defining spatial regimes based on animal communities may better reflect ecological reality than do traditional ecoregion maps, especially in our current era of rapid and unpredictable ecological change. Use an information theory based method to identify ecological boundaries and compare our results to traditional early warning

  9. Dynamic Scene Classification Using Redundant Spatial Scenelets.

    PubMed

    Du, Liang; Ling, Haibin

    2016-09-01

    Dynamic scene classification started drawing an increasing amount of research efforts recently. While existing arts mainly rely on low-level features, little work addresses the need of exploring the rich spatial layout information in dynamic scene. Motivated by the fact that dynamic scenes are characterized by both dynamic and static parts with spatial layout priors, we propose to use redundant spatial grouping of a large number of spatiotemporal patches, named scenelet, to represent a dynamic scene. Specifically, each scenelet is associated with a category-dependent scenelet model to encode the likelihood of a specific scene category. All scenelet models for a scene category are jointly learned to encode the spatial interactions and redundancies among them. Subsequently, a dynamic scene sequence is represented as a collection of category likelihoods estimated by these scenelet models. Such presentation effectively encodes the spatial layout prior together with associated semantic information, and can be used for classifying dynamic scenes in combination with a standard learning algorithm such as k -nearest neighbor or linear support vector machine. The effectiveness of our approach is clearly demonstrated using two dynamic scene benchmarks and a related application for violence video classification. In the nearest neighbor classification framework, for dynamic scene classification, our method outperforms previous state-of-the-arts on both Maryland "in the wild" dataset and "stabilized" dynamic scene dataset. For violence video classification on a benchmark dataset, our method achieves a promising classification rate of 87.08%, which significantly improves previous best result of 81.30%.

  10. Spatial Competition: Roughening of an Experimental Interface.

    PubMed

    Allstadt, Andrew J; Newman, Jonathan A; Walter, Jonathan A; Korniss, G; Caraco, Thomas

    2016-07-28

    Limited dispersal distance generates spatial aggregation. Intraspecific interactions are then concentrated within clusters, and between-species interactions occur near cluster boundaries. Spread of a locally dispersing invader can become motion of an interface between the invading and resident species, and spatial competition will produce variation in the extent of invasive advance along the interface. Kinetic roughening theory offers a framework for quantifying the development of these fluctuations, which may structure the interface as a self-affine fractal, and so induce a series of temporal and spatial scaling relationships. For most clonal plants, advance should become spatially correlated along the interface, and width of the interface (where invader and resident compete directly) should increase as a power function of time. Once roughening equilibrates, interface width and the relative location of the most advanced invader should each scale with interface length. We tested these predictions by letting white clover (Trifolium repens) invade ryegrass (Lolium perenne). The spatial correlation of clover growth developed as anticipated by kinetic roughening theory, and both interface width and the most advanced invader's lead scaled with front length. However, the scaling exponents differed from those predicted by recent simulation studies, likely due to clover's growth morphology.

  11. Quantum interference between transverse spatial waveguide modes

    PubMed Central

    Mohanty, Aseema; Zhang, Mian; Dutt, Avik; Ramelow, Sven; Nussenzveig, Paulo; Lipson, Michal

    2017-01-01

    Integrated quantum optics has the potential to markedly reduce the footprint and resource requirements of quantum information processing systems, but its practical implementation demands broader utilization of the available degrees of freedom within the optical field. To date, integrated photonic quantum systems have primarily relied on path encoding. However, in the classical regime, the transverse spatial modes of a multi-mode waveguide have been easily manipulated using the waveguide geometry to densely encode information. Here, we demonstrate quantum interference between the transverse spatial modes within a single multi-mode waveguide using quantum circuit-building blocks. This work shows that spatial modes can be controlled to an unprecedented level and have the potential to enable practical and robust quantum information processing. PMID:28106036

  12. Spatial segmentation and the black middle class.

    PubMed

    Sharkey, Patrick

    2014-01-01

    Ethnographic studies of the black middle class focus attention on the ways in which residential environments condition the experiences of different segments of the black class structure. This study places these arguments in a larger demographic context by providing a national analysis of neighborhood inequality and spatial inequality of different racial and ethnic groups in urban America. The findings show that there has been no change over time in the degree to which majority-black neighborhoods are surrounded by spatial disadvantage. Predominantly black neighborhoods, regardless of socioeconomic composition, continue to be spatially linked with areas of severe disadvantage. However, there has been substantial change in the degree to which middle- and upper-income African-American households have separated themselves from highly disadvantaged neighborhoods. These changes are driven primarily by the growing segment of middle- and upper-income African-Americans living in neighborhoods in which they are not the majority group, both in central cities and in suburbs.

  13. Running enhances spatial pattern separation in mice

    PubMed Central

    Creer, David J.; Romberg, Carola; Saksida, Lisa M.; van Praag, Henriette; Bussey, Timothy J.

    2010-01-01

    Increasing evidence suggests that regular exercise improves brain health and promotes synaptic plasticity and hippocampal neurogenesis. Exercise improves learning, but specific mechanisms of information processing influenced by physical activity are unknown. Here, we report that voluntary running enhanced the ability of adult (3 months old) male C57BL/6 mice to discriminate between the locations of two adjacent identical stimuli. Improved spatial pattern separation in adult runners was tightly correlated with increased neurogenesis. In contrast, very aged (22 months old) mice had impaired spatial discrimination and low basal cell genesis that was refractory to running. These findings suggest that the addition of newly born neurons may bolster dentate gyrus-mediated encoding of fine spatial distinctions. PMID:20133882

  14. Spatial evolution of ocean wave spectra

    NASA Technical Reports Server (NTRS)

    Beal, R. C.

    1981-01-01

    The spatially evolving deep water synthetic aperture radar (SAR) directional spectra of a mixed ocean wave system are compared with a comprehensive set of surface and aircraft measurements. The evolution of the SAR spectra, at least for ocean wavelengths greater than 80 m, is seen as generally consistent with the auxiliary data set in both time and space. From the spatial evolution of the angular component of the spectra, it is possible to project back to an apparent remote storm source that is also consistent with the storm location via GOES satellite imagery. The data provide compelling evidence that the spatial evolution of SAR ocean wave spectra can be a useful tool in global ocean wave monitoring and forecasting.

  15. Space representation in unilateral spatial neglect.

    PubMed

    Chedru, F

    1976-11-01

    Patients with unilateral brain lesions were given a task requiring exploration of space with the hand in order to assess the visual dependency of unilateral spatial neglect. The task was carried out both without visual control and under visual control. Performances were compared with that of normal subjects. Results were :(1) patients with right brain damage with no visual field defect demonstrated left-sided neglect only when the exploration was not controlled visually; (2) patients with left and right brain damage with visual field defect demonstrated contralateral neglect only when the exploration was under visual guidance. The performance of the patients with right brain damage without visual field defect in not clearly understood. The other results suggest that inner spatial representation remains intact in most cases of spatial neglect. The role of parietal lobe damage in the development of this visually induced phenomenon is hypothesised. The dominant position of vision among the senses is indicated.

  16. Measuring subwavelength spatial coherence with plasmonic interferometry

    NASA Astrophysics Data System (ADS)

    Morrill, Drew; Li, Dongfang; Pacifici, Domenico

    2016-10-01

    Optical interferometry has enabled quantification of the spatial and temporal correlations of electromagnetic fields, which laid the foundations for the theory of optical coherence. Despite significant advances in fundamental theories and applications, the measurement of nanoscale coherence lengths for highly incoherent optical fields has remained elusive. Here, we employ plasmonic interferometry (that is, optical interferometry with surface plasmons) to characterize the spatial degree of coherence of light beams down to subwavelength scales, with measured coherence lengths as low as ∼330 nm for an incident wavelength of 500 nm. Furthermore, we demonstrate a compact coherence meter that integrates this method with an image sensor. Precise determination of spatial coherence can advance high-resolution imaging and tomographic schemes, and provide an experimental platform for the development and testing of optical coherence theories at the nanoscale.

  17. High Spatial Resolution Thermal Satellite Technologies

    NASA Technical Reports Server (NTRS)

    Ryan, Robert

    2003-01-01

    This document in the form of viewslides, reviews various low-cost alternatives to high spatial resolution thermal satellite technologies. There exists no follow-on to Landsat 7 or ASTER high spatial resolution thermal systems. This document reviews the results of the investigation in to the use of new technologies to create a low-cost useful alternative. Three suggested technologies are examined. 1. Conventional microbolometer pushbroom modes offers potential for low cost Landsat Data Continuity Mission (LDCM) thermal or ASTER capability with at least 60-120 ground sampling distance (GSD). 2. Backscanning could produce MultiSpectral Thermal Imager performance without cooled detectors. 3. Cooled detector could produce hyperspectral thermal class system or extremely high spatial resolution class instrument.

  18. Psychological aspects of pilot spatial orientation.

    PubMed

    Kovalenko, P A

    1991-03-01

    Researchers examined the psychological aspects of pilot spatial orientation to aircraft attitude. Study participants completed questionnaires and made drawings of view-from-the-ground and aircraft front window and of attitude indicators, then made flights in a simulator or aircraft with unknown pitch attitude. Analysis of data indicates that pilots favored a view-from-the-ground indicator. The main drawback to the view-from-the-aircraft indicator was mobility of image. The study also examined spatial-orientation techniques pilots use in different flight phases and identified seven factors in effective spatial-orientation techniques. Other components of the study included a comparison of the manipulative capability of pilots and nonprofessional participants and pilot recall of a set of images from long-term and operational memory.

  19. Modeling of spatially-restricted intracellular signaling.

    PubMed

    Neves, Susana R

    2012-01-01

    Understanding the signaling capabilities of a cell presents a major challenge, not only due to the number of molecules involved, but also because of the complex network connectivity of intracellular signaling. Recently, the proliferation of quantitative imaging techniques has led to the discovery of the vast spatial organization of intracellular signaling. Computational modeling has emerged as a powerful tool for understanding how inhomogeneous signaling originates and is maintained. This article covers the current imaging techniques used to obtain quantitative spatial data and the mathematical approaches used to model spatial cell biology. Modeling-derived hypotheses have been experimentally tested and the integration of modeling and imaging approaches has led to non-intuitive mechanistic insights.

  20. The spatial structure of correlated neuronal variability.

    PubMed

    Rosenbaum, Robert; Smith, Matthew A; Kohn, Adam; Rubin, Jonathan E; Doiron, Brent

    2017-01-01

    Shared neural variability is ubiquitous in cortical populations. While this variability is presumed to arise from overlapping synaptic input, its precise relationship to local circuit architecture remains unclear. We combine computational models and in vivo recordings to study the relationship between the spatial structure of connectivity and correlated variability in neural circuits. Extending the theory of networks with balanced excitation and inhibition, we find that spatially localized lateral projections promote weakly correlated spiking, but broader lateral projections produce a distinctive spatial correlation structure: nearby neuron pairs are positively correlated, pairs at intermediate distances are negatively correlated and distant pairs are weakly correlated. This non-monotonic dependence of correlation on distance is revealed in a new analysis of recordings from superficial layers of macaque primary visual cortex. Our findings show that incorporating distance-dependent connectivity improves the extent to which balanced network theory can explain correlated neural variability.

  1. Spatial Evolution of Openstreetmap Dataset in Turkey

    NASA Astrophysics Data System (ADS)

    Zia, M.; Seker, D. Z.; Cakir, Z.

    2016-10-01

    Large amount of research work has already been done regarding many aspects of OpenStreetMap (OSM) dataset in recent years for developed countries and major world cities. On the other hand, limited work is present in scientific literature for developing or underdeveloped ones, because of poor data coverage. In presented study it has been demonstrated how Turkey-OSM dataset has spatially evolved in an 8 year time span (2007-2015) throughout the country. It is observed that there is an east-west spatial biasedness in OSM features density across the country. Population density and literacy level are found to be the two main governing factors controlling this spatial trend. Future research paradigms may involve considering contributors involvement and commenting about dataset health.

  2. Testing for Spatial Isotropy Under General Designs.

    PubMed

    Maity, Arnab; Sherman, Michael

    2012-05-01

    Spatial modeling is typically composed of a specification of a mean function and a model for the correlation structure. A common assumption on the spatial correlation is that it is isotropic. This means that the correlation between any two observations depends only on the distance between those sites and not on their relative orientation. The assumption of isotropy is often made due to a simpler interpretation of correlation behavior and to an easier estimation problem under an assumed isotropy. The assumption of isotropy, however, can have serious deleterious effects when not appropriate. In this paper we formulate a test of isotropy for spatial observations located according to a general class of stochastic designs. Distribution theory of our test statistic is derived and we carry out extensive simulations which verify the efficacy of our approach. We apply our methodology to a data set on longleaf pine trees from an oldgrowth forest in the southern United States.

  3. Cosmological signatures of anisotropic spatial curvature

    SciTech Connect

    Pereira, Thiago S.; Marugán, Guillermo A. Mena; Carneiro, Saulo E-mail: mena@iem.cfmac.csic.es

    2015-07-01

    If one is willing to give up the cherished hypothesis of spatial isotropy, many interesting cosmological models can be developed beyond the simple anisotropically expanding scenarios. One interesting possibility is presented by shear-free models in which the anisotropy emerges at the level of the curvature of the homogeneous spatial sections, whereas the expansion is dictated by a single scale factor. We show that such models represent viable alternatives to describe the large-scale structure of the inflationary universe, leading to a kinematically equivalent Sachs-Wolfe effect. Through the definition of a complete set of spatial eigenfunctions we compute the two-point correlation function of scalar perturbations in these models. In addition, we show how such scenarios would modify the spectrum of the CMB assuming that the observations take place in a small patch of a universe with anisotropic curvature.

  4. Auditory spatial attention using interaural time differences.

    PubMed

    Sach, A J; Hill, N I; Bailey, P J

    2000-04-01

    Previous probe-signal studies of auditory spatial attention have shown faster responses to sounds at an expected versus an unexpected location, making no distinction between the use of interaural time difference (ITD) cues and interaural-level difference cues. In 5 experiments, performance on a same-different spatial discrimination task was used in place of the reaction time metric, and sounds, presented over headphones, were lateralized only by an ITD. In all experiments, performance was better for signals lateralized on the expected side of the head, supporting the conclusion that ITDs can be used as a basis for covert orienting. The performance advantage generalized to all sounds within the spatial focus and was not dissipated by a trial-by-trial rove in frequency or by a rove in spectral profile. Successful use by the listeners of a cross-modal, centrally positioned visual cue provided evidence for top-down attentional control.

  5. Measuring spatial variability in soil characteristics

    DOEpatents

    Hoskinson, Reed L.; Svoboda, John M.; Sawyer, J. Wayne; Hess, John R.; Hess, J. Richard

    2002-01-01

    The present invention provides systems and methods for measuring a load force associated with pulling a farm implement through soil that is used to generate a spatially variable map that represents the spatial variability of the physical characteristics of the soil. An instrumented hitch pin configured to measure a load force is provided that measures the load force generated by a farm implement when the farm implement is connected with a tractor and pulled through or across soil. Each time a load force is measured, a global positioning system identifies the location of the measurement. This data is stored and analyzed to generate a spatially variable map of the soil. This map is representative of the physical characteristics of the soil, which are inferred from the magnitude of the load force.

  6. Quantum interference between transverse spatial waveguide modes

    NASA Astrophysics Data System (ADS)

    Mohanty, Aseema; Zhang, Mian; Dutt, Avik; Ramelow, Sven; Nussenzveig, Paulo; Lipson, Michal

    2017-01-01

    Integrated quantum optics has the potential to markedly reduce the footprint and resource requirements of quantum information processing systems, but its practical implementation demands broader utilization of the available degrees of freedom within the optical field. To date, integrated photonic quantum systems have primarily relied on path encoding. However, in the classical regime, the transverse spatial modes of a multi-mode waveguide have been easily manipulated using the waveguide geometry to densely encode information. Here, we demonstrate quantum interference between the transverse spatial modes within a single multi-mode waveguide using quantum circuit-building blocks. This work shows that spatial modes can be controlled to an unprecedented level and have the potential to enable practical and robust quantum information processing.

  7. Some topics in the spatial bispectra

    SciTech Connect

    Sullivan, E.

    1994-11-15

    The bispectrum can be defined as the triple fourier transform of the third order cumulant of a data series. Up to the present, except in image analysis, most work on the bispectrum has treated time series. Recently, however, there has been interest in using the bispectrum in acoustic array processing. After a look at some issues involving sampling frequencies and symmetries of the bispectrum in general, two applications of the spatial bispectrum to underwater acoustic array processing will be discussed. One is a method of processing against loss of spatial coherence in towed arrays, which takes the form of a one-dimensional image, and the other is a look at the role of spatial bispectra in matched-field processing, which is a form of model-based processing used for the localization of acoustic sound sources.

  8. Extreme Learning Machines for spatial environmental data

    NASA Astrophysics Data System (ADS)

    Leuenberger, Michael; Kanevski, Mikhail

    2015-12-01

    The use of machine learning algorithms has increased in a wide variety of domains (from finance to biocomputing and astronomy), and nowadays has a significant impact on the geoscience community. In most real cases geoscience data modelling problems are multivariate, high dimensional, variable at several spatial scales, and are generated by non-linear processes. For such complex data, the spatial prediction of continuous (or categorical) variables is a challenging task. The aim of this paper is to investigate the potential of the recently developed Extreme Learning Machine (ELM) for environmental data analysis, modelling and spatial prediction purposes. An important contribution of this study deals with an application of a generic self-consistent methodology for environmental data driven modelling based on Extreme Learning Machine. Both real and simulated data are used to demonstrate applicability of ELM at different stages of the study to understand and justify the results.

  9. Optimal estimator model for human spatial orientation

    NASA Technical Reports Server (NTRS)

    Borah, J.; Young, L. R.; Curry, R. E.

    1979-01-01

    A model is being developed to predict pilot dynamic spatial orientation in response to multisensory stimuli. Motion stimuli are first processed by dynamic models of the visual, vestibular, tactile, and proprioceptive sensors. Central nervous system function is then modeled as a steady-state Kalman filter which blends information from the various sensors to form an estimate of spatial orientation. Where necessary, this linear central estimator has been augmented with nonlinear elements to reflect more accurately some highly nonlinear human response characteristics. Computer implementation of the model has shown agreement with several important qualitative characteristics of human spatial orientation, and it is felt that with further modification and additional experimental data the model can be improved and extended. Possible means are described for extending the model to better represent the active pilot with varying skill and work load levels.

  10. Typograph: Multiscale Spatial Exploration of Text Documents

    SciTech Connect

    Endert, Alexander; Burtner, Edwin R.; Cramer, Nicholas O.; Perko, Ralph J.; Hampton, Shawn D.; Cook, Kristin A.

    2013-12-01

    Visualizing large document collections using a spatial layout of terms can enable quick overviews of information. However, these metaphors (e.g., word clouds, tag clouds, etc.) often lack interactivity to explore the information and the location and rendering of the terms are often not based on mathematical models that maintain relative distances from other information based on similarity metrics. Further, transitioning between levels of detail (i.e., from terms to full documents) can be challanging. In this paper, we present Typograph, a multi-scale spatial exploration visualization for large document collections. Based on the term-based visualization methods, Typograh enables multipel levels of detail (terms, phrases, snippets, and full documents) within the single spatialization. Further, the information is placed based on their relative similarity to other information to create the “near = similar” geography metaphor. This paper discusses the design principles and functionality of Typograph and presents a use case analyzing Wikipedia to demonstrate usage.

  11. Standing variation in spatially growing populations

    NASA Astrophysics Data System (ADS)

    Fusco, Diana; Gralka, Matti; Kayser, Jona; Hallatschek, Oskar

    Patterns of genetic diversity not only reflect the evolutionary history of a species but they can also determine the evolutionary response to environmental change. For instance, the standing genetic diversity of a microbial population can be key to rescue in the face of an antibiotic attack. While genetic diversity is in general shaped by both demography and evolution, very little is understood when both factors matter, as e.g. for biofilms with pronounced spatial organization. Here, we quantitatively explore patterns of genetic diversity by using microbial colonies and well-mixed test tube populations as antipodal model systems with extreme and very little spatial structure, respectively. We find that Eden model simulations and KPZ theory can remarkably reproduce the genetic diversity in microbial colonies obtained via population sequencing. The excellent agreement allows to draw conclusions on the resilience of spatially-organized populations and to uncover new strategies to contain antibiotic resistance.

  12. Physical exercise, neuroplasticity, spatial learning and memory.

    PubMed

    Cassilhas, Ricardo C; Tufik, Sergio; de Mello, Marco Túlio

    2016-03-01

    There has long been discussion regarding the positive effects of physical exercise on brain activity. However, physical exercise has only recently begun to receive the attention of the scientific community, with major interest in its effects on the cognitive functions, spatial learning and memory, as a non-drug method of maintaining brain health and treating neurodegenerative and/or psychiatric conditions. In humans, several studies have shown the beneficial effects of aerobic and resistance exercises in adult and geriatric populations. More recently, studies employing animal models have attempted to elucidate the mechanisms underlying neuroplasticity related to physical exercise-induced spatial learning and memory improvement, even under neurodegenerative conditions. In an attempt to clarify these issues, the present review aims to discuss the role of physical exercise in the improvement of spatial learning and memory and the cellular and molecular mechanisms involved in neuroplasticity.

  13. Spatial Feature Evaluation for Aerial Scene Analysis

    SciTech Connect

    Swearingen, Thomas S; Cheriyadat, Anil M

    2013-01-01

    High-resolution aerial images are becoming more readily available, which drives the demand for robust, intelligent and efficient systems to process increasingly large amounts of image data. However, automated image interpretation still remains a challenging problem. Robust techniques to extract and represent features to uniquely characterize various aerial scene categories is key for automated image analysis. In this paper we examined the role of spatial features to uniquely characterize various aerial scene categories. We studied low-level features such as colors, edge orientations, and textures, and examined their local spatial arrangements. We computed correlograms representing the spatial correlation of features at various distances, then measured the distance between correlograms to identify similar scenes. We evaluated the proposed technique on several aerial image databases containing challenging aerial scene categories. We report detailed evaluation of various low-level features by quantitatively measuring accuracy and parameter sensitivity. To demonstrate the feature performance, we present a simple query-based aerial scene retrieval system.

  14. Emergent universe in spatially flat cosmological model

    SciTech Connect

    Zhang, Kaituo; Yu, Hongwei; Wu, Puxun E-mail: wpx0227@gmail.com

    2014-01-01

    The scenario of an emergent universe provides a promising resolution to the big bang singularity in universes with positive or negative spatial curvature. It however remains unclear whether the scenario can be successfully implemented in a spatially flat universe which seems to be favored by present cosmological observations. In this paper, we study the stability of Einstein static state solutions in a spatially flat Shtanov-Sahni braneworld scenario. With a negative dark radiation term included and assuming a scalar field as the only matter energy component, we find that the universe can stay at an Einstein static state past eternally and then evolve to an inflation phase naturally as the scalar field climbs up its potential slowly. In addition, we also propose a concrete potential of the scalar field that realizes this scenario.

  15. Spatial transformation architectures with applications: an introduction

    NASA Astrophysics Data System (ADS)

    Schmalz, Mark S.

    1993-08-01

    Spatial transformations (STs) constitute an important class of image operations, which include the well-known affine transformation, image rotation, scaling, warping, etc. Less well known are the anisomorphic transformations among cartographic projections such as the Mercator, gnomonic, and equal-area formats. In this preliminary study, we introduce a unifying theory of spatial transformation, expressed in terms of the Image Algebra, a rigorous, inherently parallel notation for image and signal processing. Via such theory, we can predict the implementational cost of various STs. Since spatial operations are frequently I/O-intensive, we first analyze the I/O performance of well-known architectures, in order to determine their suitability for ST implementation. Analyses are verified by simulation, with emphasis upon vision-based navigation applications. An additional applications area concerns the remapping of visual receptive fields, which facilitates visual rehabilitation in the presence of retinal damage.

  16. Exploring Visuospatial Thinking in Learning about Mineralogy: Spatial Orientation Ability and Spatial Visualization Ability

    ERIC Educational Resources Information Center

    Ozdemir, Gokhan

    2010-01-01

    This mixed-method research attempted to clarify the role of visuospatial abilities in learning about mineralogy. Various sources of data--including quantitative pre- and postmeasures of spatial visualization and spatial orientation tests and achievement scores on six measures and qualitative unstructured observations, interviews, and field trip…

  17. Influence of Design Training and Spatial Solution Strategies on Spatial Ability Performance

    ERIC Educational Resources Information Center

    Lin, Hanyu

    2016-01-01

    Numerous studies have reported that spatial ability improves through training. This study investigated the following: (1) whether design training enhances spatial ability and (2) whether differing solution strategies are applied or generated following design training. On the basis of these two research objectives, this study divided the…

  18. Spatial Breakdown in Spatial Construction: Evidence from Eye Fixations in Children with Williams Syndrome

    ERIC Educational Resources Information Center

    Hoffman, James E.; Landau, Barbara; Pagani, Barney

    2003-01-01

    We investigated the role of executive and spatial representational processes in impaired performance of block construction tasks by children with Williams syndrome (WS), a rare genetic defect that results in severely impaired spatial cognition. In Experiment 1, we examined performance in two kinds of block construction tasks, Simple Puzzles, in…

  19. Part 2 The Link between GIS and spatial analysis . GIS, spatial econometrics and social science research

    NASA Astrophysics Data System (ADS)

    Anselin, Luc

    Some ideas are formulated on the challenges presented to GIS, spatial analysis and spatial econometrics that result from recent trends in social science research. These new developments are characterized by a focus on the geography of phenomena. Particular emphasis is placed on the need to extend concepts of space, to broaden the analytical toolbox and to develop software and advance education.

  20. Textbook Questions to Support Spatial Thinking: Differences in Spatiality by Question Location

    ERIC Educational Resources Information Center

    Jo, Injeong; Bednarz, Sarah W.

    2011-01-01

    This study investigates the location and varying spatiality of questions in geography textbooks. The results show that study questions posed in page margins address the three components of spatial thinking--concepts of space, using tools of representation, and processes of reasoning--more than questions in other locations within the text. Three…

  1. Spatial-Sequential and Spatial-Simultaneous Working Memory in Individuals with Williams Syndrome

    ERIC Educational Resources Information Center

    Lanfranchi, Silvia; De Mori, Letizia; Mammarella, Irene C.; Carretti, Barbara; Vianello, Renzo

    2015-01-01

    The aim of the present study was to compare visuospatial working memory performance in 18 individuals with Williams syndrome (WS) and 18 typically developing (TD) children matched for nonverbal mental age. Two aspects were considered: task presentation format (i.e., spatial-sequential or spatial-simultaneous), and level of attentional control…

  2. The Spatial and the Visual in Mental Spatial Reasoning: An Ill-Posed Distinction

    NASA Astrophysics Data System (ADS)

    Schultheis, Holger; Bertel, Sven; Barkowsky, Thomas; Seifert, Inessa

    It is an ongoing and controversial debate in cognitive science which aspects of knowledge humans process visually and which ones they process spatially. Similarly, artificial intelligence (AI) and cognitive science research, in building computational cognitive systems, tended to use strictly spatial or strictly visual representations. The resulting systems, however, were suboptimal both with respect to computational efficiency and cognitive plau sibility. In this paper, we propose that the problems in both research strands stem from a mis conception of the visual and the spatial in mental spatial knowl edge pro cessing. Instead of viewing the visual and the spatial as two clearly separable categories, they should be conceptualized as the extremes of a con tinuous dimension of representation. Regarding psychology, a continuous di mension avoids the need to exclusively assign processes and representations to either one of the cate gories and, thus, facilitates a more unambiguous rating of processes and rep resentations. Regarding AI and cognitive science, the con cept of a continuous spatial / visual dimension provides the possibility of rep re sentation structures which can vary continuously along the spatial / visual di mension. As a first step in exploiting these potential advantages of the pro posed conception we (a) introduce criteria allowing for a non-dichotomic judgment of processes and representations and (b) present an approach towards rep re sentation structures that can flexibly vary along the spatial / visual dimension.

  3. A Twin Study of Spatial and Non-Spatial Delayed Response Performance in Middle Age

    ERIC Educational Resources Information Center

    Kremen, William S.; Mai, Tuan; Panizzon, Matthew S.; Franz, Carol E.; Blankfeld, Howard M.; Xian, Hong; Eisen, Seth A.; Tsuang, Ming T.; Lyons, Michael J.

    2011-01-01

    Delayed alternation and object alternation are classic spatial and non-spatial delayed response tasks. We tested 632 middle-aged male veteran twins on variants of these tasks in order to compare test difficulty, measure their inter-correlation, test order effects, and estimate heritabilities (proportion of observed variance due to genetic…

  4. Spatial Language Facilitates Spatial Cognition: Evidence from Children Who Lack Language Input

    ERIC Educational Resources Information Center

    Gentner, Dedre; Ozyurek, Asli; Gurcanli, Ozge; Goldin-Meadow, Susan

    2013-01-01

    Does spatial language influence how people think about space? To address this question, we observed children who did not know a conventional language, and tested their performance on nonlinguistic spatial tasks. We studied deaf children living in Istanbul whose hearing losses prevented them from acquiring speech and whose hearing parents had not…

  5. Spatially constrained adaptive rewiring in cortical networks creates spatially modular small world architectures.

    PubMed

    Jarman, Nicholas; Trengove, Chris; Steur, Erik; Tyukin, Ivan; van Leeuwen, Cees

    2014-12-01

    A modular small-world topology in functional and anatomical networks of the cortex is eminently suitable as an information processing architecture. This structure was shown in model studies to arise adaptively; it emerges through rewiring of network connections according to patterns of synchrony in ongoing oscillatory neural activity. However, in order to improve the applicability of such models to the cortex, spatial characteristics of cortical connectivity need to be respected, which were previously neglected. For this purpose we consider networks endowed with a metric by embedding them into a physical space. We provide an adaptive rewiring model with a spatial distance function and a corresponding spatially local rewiring bias. The spatially constrained adaptive rewiring principle is able to steer the evolving network topology to small world status, even more consistently so than without spatial constraints. Locally biased adaptive rewiring results in a spatial layout of the connectivity structure, in which topologically segregated modules correspond to spatially segregated regions, and these regions are linked by long-range connections. The principle of locally biased adaptive rewiring, thus, may explain both the topological connectivity structure and spatial distribution of connections between neuronal units in a large-scale cortical architecture.

  6. Using a spatially explicit analysis model to evaluate spatial variation of corn yield

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Spatial irrigation of agricultural crops using site-specific variable-rate irrigation (VRI) systems is beginning to have wide-spread acceptance. However, optimizing the management of these VRI systems to conserve natural resources and increase profitability requires an understanding of the spatial ...

  7. Replacing Old Spatial Empires of the Mind: Rethinking Space and Place through Network Spatiality

    ERIC Educational Resources Information Center

    Beech, Jason; Larsen, Marianne A.

    2014-01-01

    In this article we argue for the spatialization of research on educational transfer in the field of comparative education within a theoretical framework that focuses on networks, connections, and flows. We present what we call a "spatial empire of the mind," which is comprised of a set of taken-for-granted "truths" about space…

  8. Identifying spatial priorities for protecting ecosystem services

    PubMed Central

    Luck, Gary W

    2012-01-01

    Priorities for protecting ecosystem services must be identified to ensure future human well-being. Approaches to broad-scale spatial prioritization of ecosystem services are becoming increasingly popular and are a vital precursor to identifying locations where further detailed analyses of the management of ecosystem services is required (e.g., examining trade-offs among management actions). Prioritization approaches often examine the spatial congruence between priorities for protecting ecosystem services and priorities for protecting biodiversity; therefore, the spatial prioritization method used is crucial because it will influence the alignment of service protection and conservation goals. While spatial prioritization of ecosystem services and prioritization for conservation share similarities, such as the need to document threats and costs, the former differs substantially from the latter owing to the requirement to measure the following components: supply of services; availability of human-derived alternatives to service provision; capacity to meet beneficiary demand; and site dependency in and scale of service delivery. We review studies that identify broad-scale spatial priorities for managing ecosystem services and demonstrate that researchers have used different approaches and included various measures for identifying priorities, and most studies do not consider all of the components listed above. We describe a conceptual framework for integrating each of these components into spatial prioritization of ecosystem services and illustrate our approach using a worked example for water provision. A fuller characterization of the biophysical and social context for ecosystem services that we call for should improve future prioritization and the identification of locations where ecosystem-service management is especially important or cost effective. PMID:24555017

  9. Spatial complementarity and the coexistence of species.

    PubMed

    Velázquez, Jorge; Garrahan, Juan P; Eichhorn, Markus P

    2014-01-01

    Coexistence of apparently similar species remains an enduring paradox in ecology. Spatial structure has been predicted to enable coexistence even when population-level models predict competitive exclusion if it causes each species to limit its own population more than that of its competitor. Nevertheless, existing hypotheses conflict with regard to whether clustering favours or precludes coexistence. The spatial segregation hypothesis predicts that in clustered populations the frequency of intra-specific interactions will be increased, causing each species to be self-limiting. Alternatively, individuals of the same species might compete over greater distances, known as heteromyopia, breaking down clusters and opening space for a second species to invade. In this study we create an individual-based model in homogeneous two-dimensional space for two putative sessile species differing only in their demographic rates and the range and strength of their competitive interactions. We fully characterise the parameter space within which coexistence occurs beyond population-level predictions, thereby revealing a region of coexistence generated by a previously-unrecognised process which we term the triadic mechanism. Here coexistence occurs due to the ability of a second generation of offspring of the rarer species to escape competition from their ancestors. We diagnose the conditions under which each of three spatial coexistence mechanisms operates and their characteristic spatial signatures. Deriving insights from a novel metric - ecological pressure - we demonstrate that coexistence is not solely determined by features of the numerically-dominant species. This results in a common framework for predicting, given any pair of species and knowledge of the relevant parameters, whether they will coexist, the mechanism by which they will do so, and the resultant spatial pattern of the community. Spatial coexistence arises from complementary combinations of traits in each species

  10. A Spatial Statistical Model for Landscape Genetics

    PubMed Central

    Guillot, Gilles; Estoup, Arnaud; Mortier, Frédéric; Cosson, Jean François

    2005-01-01

    Landscape genetics is a new discipline that aims to provide information on how landscape and environmental features influence population genetic structure. The first key step of landscape genetics is the spatial detection and location of genetic discontinuities between populations. However, efficient methods for achieving this task are lacking. In this article, we first clarify what is conceptually involved in the spatial modeling of genetic data. Then we describe a Bayesian model implemented in a Markov chain Monte Carlo scheme that allows inference of the location of such genetic discontinuities from individual geo-referenced multilocus genotypes, without a priori knowledge on populational units and limits. In this method, the global set of sampled individuals is modeled as a spatial mixture of panmictic populations, and the spatial organization of populations is modeled through the colored Voronoi tessellation. In addition to spatially locating genetic discontinuities, the method quantifies the amount of spatial dependence in the data set, estimates the number of populations in the studied area, assigns individuals to their population of origin, and detects individual migrants between populations, while taking into account uncertainty on the location of sampled individuals. The performance of the method is evaluated through the analysis of simulated data sets. Results show good performances for standard data sets (e.g., 100 individuals genotyped at 10 loci with 10 alleles per locus), with high but also low levels of population differentiation (e.g., FST < 0.05). The method is then applied to a set of 88 individuals of wolverines (Gulo gulo) sampled in the northwestern United States and genotyped at 10 microsatellites. PMID:15520263

  11. Visual Attention during Spatial Language Comprehension

    PubMed Central

    Burigo, Michele; Knoeferle, Pia

    2015-01-01

    Spatial terms such as “above”, “in front of”, and “on the left of” are all essential for describing the location of one object relative to another object in everyday communication. Apprehending such spatial relations involves relating linguistic to object representations by means of attention. This requires at least one attentional shift, and models such as the Attentional Vector Sum (AVS) predict the direction of that attention shift, from the sausage to the box for spatial utterances such as “The box is above the sausage”. To the extent that this prediction generalizes to overt gaze shifts, a listener’s visual attention should shift from the sausage to the box. However, listeners tend to rapidly look at referents in their order of mention and even anticipate them based on linguistic cues, a behavior that predicts a converse attentional shift from the box to the sausage. Four eye-tracking experiments assessed the role of overt attention in spatial language comprehension by examining to which extent visual attention is guided by words in the utterance and to which extent it also shifts “against the grain” of the unfolding sentence. The outcome suggests that comprehenders’ visual attention is predominantly guided by their interpretation of the spatial description. Visual shifts against the grain occurred only when comprehenders had some extra time, and their absence did not affect comprehension accuracy. However, the timing of this reverse gaze shift on a trial correlated with that trial’s verification time. Thus, while the timing of these gaze shifts is subtly related to the verification time, their presence is not necessary for successful verification of spatial relations. PMID:25607540

  12. Spatial Complementarity and the Coexistence of Species

    PubMed Central

    Velázquez, Jorge; Garrahan, Juan P.; Eichhorn, Markus P.

    2014-01-01

    Coexistence of apparently similar species remains an enduring paradox in ecology. Spatial structure has been predicted to enable coexistence even when population-level models predict competitive exclusion if it causes each species to limit its own population more than that of its competitor. Nevertheless, existing hypotheses conflict with regard to whether clustering favours or precludes coexistence. The spatial segregation hypothesis predicts that in clustered populations the frequency of intra-specific interactions will be increased, causing each species to be self-limiting. Alternatively, individuals of the same species might compete over greater distances, known as heteromyopia, breaking down clusters and opening space for a second species to invade. In this study we create an individual-based model in homogeneous two-dimensional space for two putative sessile species differing only in their demographic rates and the range and strength of their competitive interactions. We fully characterise the parameter space within which coexistence occurs beyond population-level predictions, thereby revealing a region of coexistence generated by a previously-unrecognised process which we term the triadic mechanism. Here coexistence occurs due to the ability of a second generation of offspring of the rarer species to escape competition from their ancestors. We diagnose the conditions under which each of three spatial coexistence mechanisms operates and their characteristic spatial signatures. Deriving insights from a novel metric — ecological pressure — we demonstrate that coexistence is not solely determined by features of the numerically-dominant species. This results in a common framework for predicting, given any pair of species and knowledge of the relevant parameters, whether they will coexist, the mechanism by which they will do so, and the resultant spatial pattern of the community. Spatial coexistence arises from complementary combinations of traits in each

  13. Spatial anxiety relates to spatial abilities as a function of working memory in children.

    PubMed

    Ramirez, Gerardo; Gunderson, Elizabeth A; Levine, Susan C; Beilock, Sian L

    2012-01-01

    Spatial ability is a strong predictor of students' pursuit of higher education in science and mathematics. However, very little is known about the affective factors that influence individual differences in spatial ability, particularly at a young age. We examine the role of spatial anxiety in young children's performance on a mental rotation task. We show that even at a young age, children report experiencing feelings of nervousness at the prospect of engaging in spatial activities. Moreover, we show that these feelings are associated with reduced mental rotation ability among students with high but not low working memory (WM). Interestingly, this WM × spatial anxiety interaction was only found among girls. We discuss these patterns of results in terms of the problem-solving strategies that boys versus girls use in solving mental rotation problems.

  14. Young's experiment with electromagnetic spatial coherence wavelets.

    PubMed

    Castaneda, Roman; Carrasquilla, Juan; Garcia-Sucerquia, Jorge

    2006-10-01

    We discuss Young's experiment with electromagnetic random fields at arbitrary states of coherence and polarization within the framework of the electric spatial coherence wavelets. The use of this approach for the electromagnetic spatial coherence theory allows us to envisage the existence of polarization domains inside the observation plane. We show that it is possible to locally control those polarization domains by means of the correlation properties of the electromagnetic wave. To show the validity of this alternative approach, we derive by means of numerical modeling the classical Fresnel-Arago interference laws.

  15. [Temporal and spatial representations of tactile sensation].

    PubMed

    Yamamoto, Shinya

    2014-04-01

    How does the brain encode "when" and "where" events that have occurred during tactile sensory processing? The simplest protocol to address this question would be asking participants to judge the temporal order of tactile stimuli delivered to both hands while varying their spatial relationship. In this review, I will focus on the illusion that the subjective temporal order of two tactile stimuli (one delivered to each hand) is reversed when the arms are crossed. By introducing recent findings related to this illusion, I will discuss how the temporal and spatial representations of tactile sensation interact with each other, and propose neural mechanisms potentially underlying this interaction.

  16. Spatial reasoning in remotely sensed data

    NASA Technical Reports Server (NTRS)

    Campbell, J.; Ehrich, R. W.; Elliott, D.; Haralick, R. M.; Wang, S.

    1981-01-01

    Photointerpreters employ a variety of implicit spatial models to provide interpretations from remotely sensed aerial or satellite imagery. In this paper one application is illustrated: how ridges and valleys can be automatically interpreted from Landsat imagery of a mountainous area, and how a relative elevation terrain model can be constructed from this interpretation. How to examine valleys for the possible presence of streams or rivers is shown, and how a spatial relational model can be set up to make a final interpretation of the river drainage network is explored.

  17. Desynchronization and spatial effects in multistrain diseases

    NASA Astrophysics Data System (ADS)

    Shaw, Leah; Billings, Lora; Schwartz, Ira

    2006-03-01

    Dengue fever, a multistrain disease, has four distinct co- existing serotypes (strains). The serotypes interact by antibody- dependent enhancement (ADE), in which infection with a single serotype is asymptomatic, but contact with a second serotype leads to serious illness accompanied by greater infectivity. We present a compartmental model for multiple serotypes with ADE, and consider autonomous, seasonally driven, and stochastic versions of the model. Spatial effects are included in a multipatch model. We observe desynchronization between outbreaks of the different serotypes, as well as desynchronization between spatially distinct regions.

  18. On Tenth Order Central Spatial Schemes

    SciTech Connect

    Sjogreen, B; Yee, H C

    2007-05-14

    This paper explores the performance of the tenth-order central spatial scheme and derives the accompanying energy-norm stable summation-by-parts (SBP) boundary operators. The objective is to employ the resulting tenth-order spatial differencing with the stable SBP boundary operators as a base scheme in the framework of adaptive numerical dissipation control in high order multistep filter schemes of Yee et al. (1999), Yee and Sj{umlt o}green (2002, 2005, 2006, 2007), and Sj{umlt o}green and Yee (2004). These schemes were designed for multiscale turbulence flows including strong shock waves and combustion.

  19. The spatial distribution of coronae on Venus

    NASA Technical Reports Server (NTRS)

    Squyres, S. W.; Schubert, G.; Bindschadler, D. L.; Janes, D. M.; Moersch, J. E.; Moore, W.; Olson, P.; Ratcliff, J. T.; Stofan, E. R.; Turcotte, D. L.

    1992-01-01

    Coronae on Venus are large, generally circular surface features that have distinctive tectonic, volcanic, and topographic expressions. They range in diameter from less than 200 km to at least 1000 km. Data from the Magellan spacecraft have now allowed complete global mapping of the spatial distribution of coronae on the planet. Unlike impact craters, which show a random (i.e., Poisson) spatial distribution, the distribution of coronae appears to be nonrandom. We investigate the distribution here in detail, and explore its implications in terms of mantle convection and surface modification processes.

  20. Site characterization: a spatial estimation approach

    SciTech Connect

    Candy, J.V.; Mao, N.

    1980-10-01

    In this report the application of spatial estimation techniques or kriging to groundwater aquifers and geological borehole data is considered. The adequacy of these techniques to reliably develop contour maps from various data sets is investigated. The estimator is developed theoretically in a simplified fashion using vector-matrix calculus. The practice of spatial estimation is discussed and the estimator is then applied to two groundwater aquifer systems and used also to investigate geological formations from borehole data. It is shown that the estimator can provide reasonable results when designed properly.

  1. Spatial disorientation in right-hemisphere infarction.

    PubMed Central

    Meerwaldt, J D; van Harskamp, F

    1982-01-01

    Spatial orientation was tested with the rod orientation test. The subjects were 40 normal controls and 68 brain-damaged patients with cerebral infarcts. Patients in whom the lesion included the post-rolandic region of the right hemisphere performed worse than controls or patients with lesions at other sites. Patients with an exclusively postrolandic (usually occipital) lesion showed higher error rates than patients with a combined prerolandic and postrolandic lesion, but only for the visual part of the test. These patients were re-examined one year after the stroke. Most of them showed an incomplete recovery of spatial function. PMID:7119828

  2. A simplified spatial model for BWR stability

    SciTech Connect

    Berman, Y.; Lederer, Y.; Meron, E.

    2012-07-01

    A spatial reduced order model for the study of BWR stability, based on the phenomenological model of March-Leuba et al., is presented. As one dimensional spatial dependence of the neutron flux, fuel temperature and void fraction is introduced, it is possible to describe both global and regional oscillations of the reactor power. Both linear stability analysis and numerical analysis were applied in order to describe the parameters which govern the model stability. The results were found qualitatively similar to past results. Doppler reactivity feedback was found essential for the explanation of the different regions of the flow-power stability map. (authors)

  3. Spatial Operator Algebra for multibody system dynamics

    NASA Technical Reports Server (NTRS)

    Rodriguez, G.; Jain, A.; Kreutz-Delgado, K.

    1992-01-01

    The Spatial Operator Algebra framework for the dynamics of general multibody systems is described. The use of a spatial operator-based methodology permits the formulation of the dynamical equations of motion of multibody systems in a concise and systematic way. The dynamical equations of progressively more complex grid multibody systems are developed in an evolutionary manner beginning with a serial chain system, followed by a tree topology system and finally, systems with arbitrary closed loops. Operator factorizations and identities are used to develop novel recursive algorithms for the forward dynamics of systems with closed loops. Extensions required to deal with flexible elements are also discussed.

  4. Spatial filtering of radiation from wire lasers

    NASA Astrophysics Data System (ADS)

    Orlova, E. E.; Solyankin, P. M.; Angeluts, A. A.; Lee, A.; Kosareva, O. G.; Ozheredov, I. A.; Balakin, A. V.; Andreeva, V. A.; Panov, N. A.; Aksenov, V. N.; Shkurinov, A. P.

    2017-04-01

    In this letter we propose an approach to obtain directive radiation from wire lasers with subwavelength transverse dimensions and length much larger than the radiation wavelength (wire lasers) based on spatial filtering of their radiation using a combination of a spherical lens and a diaphragm. Theoretical modeling based on the antenna model for wire lasers shows that a directive beam with the uniform phase front can be formed when the diaphragm separates the maximum of the image field of the laser created by the lens. We demonstrate spatial filtering of wire laser radiation experimentally using a terahertz quantum cascade laser.

  5. Detection and recognition of simple spatial forms

    NASA Technical Reports Server (NTRS)

    Watson, A. B.

    1983-01-01

    A model of human visual sensitivity to spatial patterns is constructed. The model predicts the visibility and discriminability of arbitrary two-dimensional monochrome images. The image is analyzed by a large array of linear feature sensors, which differ in spatial frequency, phase, orientation, and position in the visual field. All sensors have one octave frequency bandwidths, and increase in size linearly with eccentricity. Sensor responses are processed by an ideal Bayesian classifier, subject to uncertainty. The performance of the model is compared to that of the human observer in detecting and discriminating some simple images.

  6. Fundamental Limits of Spatial Resolution in PET

    PubMed Central

    Moses, William W.

    2010-01-01

    The fundamental limits of spatial resolution in positron emission tomography (PET) have been understood for many years. The physical size of the detector element usually plays the dominant role in determining resolution, but the combined contributions from acollinearity, positron range, penetration into the detector ring, and decoding errors in the detector modules often combine to be of similar size. In addition, the sampling geometry and statistical noise further degrade the effective resolution. This paper describes quantitatively describes these effects, discusses potential methods for reducing the magnitude of these effects, and computes the ultimately achievable spatial resolution for clinical and pre-clinical PET cameras. PMID:21804677

  7. Spatial Modulation Improves Performance in CTIS

    NASA Technical Reports Server (NTRS)

    Bearman, Gregory H.; Wilson, Daniel W.; Johnson, William R.

    2009-01-01

    Suitably formulated spatial modulation of a scene imaged by a computed-tomography imaging spectrometer (CTIS) has been found to be useful as a means of improving the imaging performance of the CTIS. As used here, "spatial modulation" signifies the imposition of additional, artificial structure on a scene from within the CTIS optics. The basic principles of a CTIS were described in "Improvements in Computed- Tomography Imaging Spectrometry" (NPO-20561) NASA Tech Briefs, Vol. 24, No. 12 (December 2000), page 38 and "All-Reflective Computed-Tomography Imaging Spectrometers" (NPO-20836), NASA Tech Briefs, Vol. 26, No. 11 (November 2002), page 7a. To recapitulate: A CTIS offers capabilities for imaging a scene with spatial, spectral, and temporal resolution. The spectral disperser in a CTIS is a two-dimensional diffraction grating. It is positioned between two relay lenses (or on one of two relay mirrors) in a video imaging system. If the disperser were removed, the system would produce ordinary images of the scene in its field of view. In the presence of the grating, the image on the focal plane of the system contains both spectral and spatial information because the multiple diffraction orders of the grating give rise to multiple, spectrally dispersed images of the scene. By use of algorithms adapted from computed tomography, the image on the focal plane can be processed into an image cube a three-dimensional collection of data on the image intensity as a function of the two spatial dimensions (x and y) in the scene and of wavelength (lambda). Thus, both spectrally and spatially resolved information on the scene at a given instant of time can be obtained, without scanning, from a single snapshot; this is what makes the CTIS such a potentially powerful tool for spatially, spectrally, and temporally resolved imaging. A CTIS performs poorly in imaging some types of scenes in particular, scenes that contain little spatial or spectral variation. The computed spectra of

  8. Conservative spatial chaos of buckled elastic linkages.

    PubMed

    Kocsis, Attila; Károlyi, György

    2006-09-01

    Buckling of an elastic linkage under general loading is investigated. We show that buckling is related to an initial value problem, which is always a conservative, area-preserving mapping, even if the original static problem is nonconservative. In some special cases, we construct the global bifurcation diagrams, and argue that their complicated structure is a consequence of spatial chaos. We characterize spatial chaos by the associated initial value problem's topological entropy, which turns out to be related to the number of buckled configurations.

  9. On the temporal dynamics of spatial stimulus-response transfer between spatial incompatibility and Simon tasks

    PubMed Central

    Ivanoff, Jason; Blagdon, Ryan; Feener, Stefanie; McNeil, Melanie; Muir, Paul H.

    2014-01-01

    The Simon effect refers to the performance (response time and accuracy) advantage for responses that spatially correspond to the task-irrelevant location of a stimulus. It has been attributed to a natural tendency to respond toward the source of stimulation. When location is task-relevant, however, and responses are intentionally directed away (incompatible) or toward (compatible) the source of the stimulation, there is also an advantage for spatially compatible responses over spatially incompatible responses. Interestingly, a number of studies have demonstrated a reversed, or reduced, Simon effect following practice with a spatial incompatibility task. One interpretation of this finding is that practicing a spatial incompatibility task disables the natural tendency to respond toward stimuli. Here, the temporal dynamics of this stimulus-response (S-R) transfer were explored with speed-accuracy trade-offs (SATs). All experiments used the mixed-task paradigm in which Simon and spatial compatibility/incompatibility tasks were interleaved across blocks of trials. In general, bidirectional S-R transfer was observed: while the spatial incompatibility task had an influence on the Simon effect, the task-relevant S-R mapping of the Simon task also had a small impact on congruency effects within the spatial compatibility and incompatibility tasks. These effects were generally greater when the task contexts were similar. Moreover, the SAT analysis of performance in the Simon task demonstrated that the tendency to respond to the location of the stimulus was not eliminated because of the spatial incompatibility task. Rather, S-R transfer from the spatial incompatibility task appeared to partially mask the natural tendency to respond to the source of stimulation with a conflicting inclination to respond away from it. These findings support the use of SAT methodology to quantitatively describe rapid response tendencies. PMID:25191217

  10. On the temporal dynamics of spatial stimulus-response transfer between spatial incompatibility and Simon tasks.

    PubMed

    Ivanoff, Jason; Blagdon, Ryan; Feener, Stefanie; McNeil, Melanie; Muir, Paul H

    2014-01-01

    The Simon effect refers to the performance (response time and accuracy) advantage for responses that spatially correspond to the task-irrelevant location of a stimulus. It has been attributed to a natural tendency to respond toward the source of stimulation. When location is task-relevant, however, and responses are intentionally directed away (incompatible) or toward (compatible) the source of the stimulation, there is also an advantage for spatially compatible responses over spatially incompatible responses. Interestingly, a number of studies have demonstrated a reversed, or reduced, Simon effect following practice with a spatial incompatibility task. One interpretation of this finding is that practicing a spatial incompatibility task disables the natural tendency to respond toward stimuli. Here, the temporal dynamics of this stimulus-response (S-R) transfer were explored with speed-accuracy trade-offs (SATs). All experiments used the mixed-task paradigm in which Simon and spatial compatibility/incompatibility tasks were interleaved across blocks of trials. In general, bidirectional S-R transfer was observed: while the spatial incompatibility task had an influence on the Simon effect, the task-relevant S-R mapping of the Simon task also had a small impact on congruency effects within the spatial compatibility and incompatibility tasks. These effects were generally greater when the task contexts were similar. Moreover, the SAT analysis of performance in the Simon task demonstrated that the tendency to respond to the location of the stimulus was not eliminated because of the spatial incompatibility task. Rather, S-R transfer from the spatial incompatibility task appeared to partially mask the natural tendency to respond to the source of stimulation with a conflicting inclination to respond away from it. These findings support the use of SAT methodology to quantitatively describe rapid response tendencies.

  11. The integration of straight contours (snakes and ladders): The role of spatial arrangement, spatial frequency and spatial phase.

    PubMed

    Bellacosa Marotti, Rosilari; Pavan, Andrea; Casco, Clara

    2012-10-15

    In the present study we addressed the issue of whether the Gestalt principle of grouping by similarity (iso-orientation) subtends extraction of straight contours made up of disconnected, iso-oriented Gabor elements, whether collinear (snakes) or parallel (ladders). To prevent the use of the most obvious grouping principle of good continuation, which allows us to perceive the relation between local and global orientation along the contour, we manipulated the spatial arrangement of randomly oriented Gabors in the background: they were positioned on an ordered grid, and grouped on the basis of good continuation, or randomly positioned and not grouped. Grid-positioned backgrounds exert a suppressive contextual influence on detection of good continuation along the contour path. Results obtained in a two-interval forced choice task showed that the orderly-positioned background did not completely prevent detection of snakes and ladders. Detection of snakes was hampered at low spatial frequency whereas detection of ladders was improved by the randomly-positioned background at high spatial frequency. These contextual influences support the suggestion that both iso-orientation and good continuation rules are employed by the association field underlying the binding of straight contours. In addition, they are not compatible with integration of snakes and ladders elements within a single receptive field. In support of this suggestion we found that phase constancy within contour elements (as opposed to phase randomization) improved snake detectability at low spatial frequency, and, unexpectedly, impaired ladder detectability at high spatial frequency. This suggests that a low-level mechanism based on the balance between excitatory and inhibitory lateral interactions at a first stage may account for the detection of both straight contours.

  12. Spatial vulnerability assessments by regression kriging

    NASA Astrophysics Data System (ADS)

    Pásztor, László; Laborczi, Annamária; Takács, Katalin; Szatmári, Gábor

    2016-04-01

    Two fairly different complex environmental phenomena, causing natural hazard were mapped based on a combined spatial inference approach. The behaviour is related to various environmental factors and the applied approach enables the inclusion of several, spatially exhaustive auxiliary variables that are available for mapping. Inland excess water (IEW) is an interrelated natural and human induced phenomenon causes several problems in the flat-land regions of Hungary, which cover nearly half of the country. The term 'inland excess water' refers to the occurrence of inundations outside the flood levee that originate from sources differing from flood overflow, it is surplus surface water forming due to the lack of runoff, insufficient absorption capability of soil or the upwelling of groundwater. There is a multiplicity of definitions, which indicate the complexity of processes that govern this phenomenon. Most of the definitions have a common part, namely, that inland excess water is temporary water inundation that occurs in flat-lands due to both precipitation and groundwater emerging on the surface as substantial sources. Radon gas is produced in the radioactive decay chain of uranium, which is an element that is naturally present in soils. Radon is transported mainly by diffusion and convection mechanisms through the soil depending mainly on soil physical and meteorological parameters and can enter and accumulate in the buildings. Health risk originating from indoor radon concentration attributed to natural factors is characterized by geogenic radon potential (GRP). In addition to geology and meteorology, physical soil properties play significant role in the determination of GRP. Identification of areas with high risk requires spatial modelling, that is mapping of specific natural hazards. In both cases external environmental factors determine the behaviour of the target process (occurrence/frequncy of IEW and grade of GRP respectively). Spatial auxiliary

  13. Comparison of Spatial Skills of Students Entering Different Engineering Majors

    ERIC Educational Resources Information Center

    Veurink, N.; Sorby, S. A.

    2012-01-01

    Spatial skills have been shown to be important to success in an engineering curriculum, and some question if poor spatial skills prevent students from entering STEM fields or if students with weak spatial skills avoid engineering disciplines believed to highly spatially-oriented. Veurink and Hamlin (2011) found that freshmen students entering…

  14. A New Methodology of Spatial Cross-Correlation Analysis

    PubMed Central

    Chen, Yanguang

    2015-01-01

    Spatial correlation modeling comprises both spatial autocorrelation and spatial cross-correlation processes. The spatial autocorrelation theory has been well-developed. It is necessary to advance the method of spatial cross-correlation analysis to supplement the autocorrelation analysis. This paper presents a set of models and analytical procedures for spatial cross-correlation analysis. By analogy with Moran’s index newly expressed in a spatial quadratic form, a theoretical framework is derived for geographical cross-correlation modeling. First, two sets of spatial cross-correlation coefficients are defined, including a global spatial cross-correlation coefficient and local spatial cross-correlation coefficients. Second, a pair of scatterplots of spatial cross-correlation is proposed, and the plots can be used to visually reveal the causality behind spatial systems. Based on the global cross-correlation coefficient, Pearson’s correlation coefficient can be decomposed into two parts: direct correlation (partial correlation) and indirect correlation (spatial cross-correlation). As an example, the methodology is applied to the relationships between China’s urbanization and economic development to illustrate how to model spatial cross-correlation phenomena. This study is an introduction to developing the theory of spatial cross-correlation, and future geographical spatial analysis might benefit from these models and indexes. PMID:25993120

  15. Think3d!: Improving mathematics learning through embodied spatial training.

    PubMed

    Burte, Heather; Gardony, Aaron L; Hutton, Allyson; Taylor, Holly A

    2017-01-01

    Spatial thinking skills positively relate to Science, Technology, Engineering, and Math (STEM) outcomes, but spatial training is largely absent in elementary school. Elementary school is a time when children develop foundational cognitive skills that will support STEM learning throughout their education. Spatial thinking should be considered a foundational cognitive skill. The present research examined the impact of an embodied spatial training program on elementary students' spatial and mathematical thinking. Students in rural elementary schools completed spatial and math assessments prior to and after participating in an origami and pop-up paper engineering-based program, called Think3d!. Think3d! uses embodied tasks, such as folding and cutting paper, to train two-dimensional to three-dimensional spatial thinking. Analyses explored spatial thinking gains, mathematics gains - specifically for problem types expected to show gains from spatial training - and factors predicting mathematics gains. Results showed spatial thinking gains in two assessments. Using a math categorization to target problems more and less likely to be impacted by spatial training, we found that all students improved on real-world math problems and older students improved on visual and spatial math problems. Further, the results are suggestive of developmental time points for implementing embodied spatial training related to applying spatial thinking to math. Finally, the spatial thinking assessment that was most highly related to training activities also predicted math performance gains. Future research should explore developmental issues related to how embodied spatial training might support STEM learning and outcomes.

  16. Estimation of Spatial Dynamic Nonparametric Durbin Models with Fixed Effects

    ERIC Educational Resources Information Center

    Qian, Minghui; Hu, Ridong; Chen, Jianwei

    2016-01-01

    Spatial panel data models have been widely studied and applied in both scientific and social science disciplines, especially in the analysis of spatial influence. In this paper, we consider the spatial dynamic nonparametric Durbin model (SDNDM) with fixed effects, which takes the nonlinear factors into account base on the spatial dynamic panel…

  17. Getting the Big Picture: Development of Spatial Scaling Abilities

    ERIC Educational Resources Information Center

    Frick, Andrea; Newcombe, Nora S.

    2012-01-01

    Spatial scaling is an integral aspect of many spatial tasks that involve symbol-to-referent correspondences (e.g., map reading, drawing). In this study, we asked 3-6-year-olds and adults to locate objects in a two-dimensional spatial layout using information from a second spatial representation (map). We examined how scaling factor and reference…

  18. Double Dissociations in Visual and Spatial Short-Term Memory

    ERIC Educational Resources Information Center

    Klauer, Karl Christoph; Zhao, Zengmei

    2004-01-01

    A visual short-term memory task was more strongly disrupted by visual than spatial interference, and a spatial memory task was simultaneously more strongly disrupted by spatial than visual interference. This double dissociation supports a fractionation of visuospatial short-term memory into separate visual and spatial components. In 6 experiments,…

  19. A spatially referenced regression model (SPARROW) for suspended sediment in streams of the Conterminous U.S.

    USGS Publications Warehouse

    Schwarz, Gregory E.; Smith, Richard A.; Alexander, Richard B.; Gray, John R.

    2001-01-01

    ). Conversely, relatively little direct evidence is available concerning the fate of sediment. The common practice of quantifying sediment fate with a sediment deliv ery ratio, estimated from a simple empirical relation with upstream basin area, does not artic ulate the relative importance of individual storage sites within a basin (Wolman, 1977). Rates of sediment deposition in reservoirs and flood plains can be determined from empirical measurement s , but only a limited number of sites have been monitored, and net rates of deposition or loss from other potential sinks and sources is largely unknown (Stallard, 1998). In particular, little is known about how much sediment loss from fields ultimately makes its way to stream channels, and how much sediment is subsequently stored in or lost from th e streambed (Meade and Parker, 1985, Trimble and Crosson, 2000). This paper reports on recent progress made to a ddress empirically the question of sediment fate and transport on a national scale. The model pres ented here is based on the SPAtially Referenced Regression On Watershed attr ibutes (SPARROW) methodology, fi rst used to estimate the distribution of nutrients in str eams and rivers of the United Stat es, and subsequently shown to describe land and stream processes affecting the delivery of nutrients (Smith and others, 1997, Alexander and others, 2000, Preston and Brakeb ill, 1999). The model makes use of numerous spatial datasets, available at the national level, to explain long-term sediment water-quality conditions in major streams and rivers throughou t the United States. Sediment sources are identified using sediment erosion rates from the National Resources I nventory (NRI) (Natural Resources Conservation Service, 2000) and apportioned over the landscape according to 30- meter resolution land-use information from th e National Land Cover Data set (NLCD) (U.S. Geological Survey, 2000a). More than 76,000 reservoirs from the National Inventory of Dams (NID) (U.S. Army

  20. Latent spatial models and sampling design for landscape genetics

    USGS Publications Warehouse

    Hanks, Ephraim M.; Hooten, Mevin B.; Knick, Steven T.; Oyler-McCance, Sara J.; Fike, Jennifer A.; Cross, Todd B.; Schwartz, Michael K.

    2016-01-01

    We propose a spatially-explicit approach for modeling genetic variation across space and illustrate how this approach can be used to optimize spatial prediction and sampling design for landscape genetic data. We propose a multinomial data model for categorical microsatellite allele data commonly used in landscape genetic studies, and introduce a latent spatial random effect to allow for spatial correlation between genetic observations. We illustrate how modern dimension reduction approaches to spatial statistics can allow for efficient computation in landscape genetic statistical models covering large spatial domains. We apply our approach to propose a retrospective spatial sampling design for greater sage-grouse (Centrocercus urophasianus) population genetics in the western United States.

  1. Growing Up Literate: Spelling and Spatial Relationships.

    ERIC Educational Resources Information Center

    Staples, Betsy

    1984-01-01

    Reviews two spelling packages ("Spelldiver" and "Attack of the Spelling Bees") and a reading program ("The Word Bird"), which teaches spatial relationships while encouraging the young reader to read carefully. Includes suggested age(s), hardware needed, current price, manufacturer, distributor, and in-depth evaluation…

  2. GRISO: Spatial Interpolation Generator from Rainfall Observations

    NASA Astrophysics Data System (ADS)

    Rebora, Nicola; Pignone, Flavio; Silvestro, Francesco

    2015-04-01

    The estimation of rainfall fields, especially its spatial distribution and position is a crucial task both for rainfall nowcasting and for modeling catchment response to rainfall. In the past years several studies on the spatialization of rainfall from raingauge were made and many mathematical methods to cope with this problem were developed. The most known is the Kriging (Matheron, 1967). A new geostatistical algorithm called GRISO (Spatial Interpolation Generator from Rainfall Observations) was implemented. The GRISO method, similar to Kriging, was developed in order that the output map maintains the observed "real" rainfall value on the raingauges position but is conditioned to reach the mean of the field far from the gauges. The main innovation is the improved computational time, the associated map of variance and above all the possibility of using more than one semivariogram for spatialize the information. The GRISO algorithm has been applied is Italy, where is available a dense network of raingauges (about 3000 stations). A validation of the GRISO method was done on a large number of Italian past events. Several statistical scores have been applied to compare it with Kriging. The new algorithm is operationally used by the Italian Civil Protection Department.

  3. Landscapes, Spatial Justice and Learning Communities

    ERIC Educational Resources Information Center

    Armstrong, Felicity

    2012-01-01

    This paper draws on a study of a community-based adult education initiative, "Cumbria Credits," which took place during the period of serious economic decline which hit sections of the farming and the wider community in Cumbria during 2001. It draws on the principles underpinning Edward Soja's notion of "spatial justice" to explore transformations…

  4. Innovative Allies: Spatial and Creative Abilities

    ERIC Educational Resources Information Center

    Coxon, Steve V.

    2012-01-01

    Spatial and creative abilities are important for innovations in science, technology, engineering, and math (STEM) fields, but talents are rarely developed from these abilities by schools, including among gifted children and adolescents who have a high potential to become STEM innovators. This article provides an overview of each ability and makes…

  5. Visualizing Spatial Dependencies in Network Topology

    DTIC Science & Technology

    2010-07-12

    terrorism, and Security held in conjunction with the SIAM International Conference on Data Mining (SDM), April 2008. [18] S Openshaw and S Alvandies...spatial distributions. John Wiley & Sons, New York, 2 edition, 1999. [19] S. Openshaw and PJ Taylor. The modifiable areal unit problem. Quantitative

  6. Spatial uniformity measurement of SAW convolvers

    NASA Astrophysics Data System (ADS)

    Selviah, D. R.; Warne, D. H.; Morgan, D. P.

    1982-09-01

    For correlation of coded waveforms, the nonlinear interactive process in a SAW convolver should ideally give an amplitude and phase independent of position. A new experimental method of measuring this spatial uniformity used CW test waveforms and gave a resolution of 25 ns - a considerably higher resolution than previously attained.

  7. The Spatial Scale of Detected Seismicity

    NASA Astrophysics Data System (ADS)

    Mignan, A.; Chen, C.-C.

    2016-01-01

    An experimental method for the spatial resolution analysis of the earthquake frequency-magnitude distribution is introduced in order to identify the intrinsic spatial scale of the detected seismicity phenomenon. We consider the unbounded magnitude range m ∈ (-∞, +∞), which includes incomplete data below the completeness magnitude m c. By analyzing a relocated earthquake catalog of Taiwan, we find that the detected seismicity phenomenon is scale-variant for m ∈ (-∞, +∞) with its spatial grain a function of the configuration of the seismic network, while seismicity is known to be scale invariant for m ∈ [ m c, +∞). Correction for data incompleteness for m < m c based on the knowledge of the spatial scale of the process allows extending the analysis of the Gutenberg-Richter law and of the fractal dimension to lower magnitudes. This shall allow verifying the continuity of universality of these parameters over a wider magnitude range. Our results also suggest that the commonly accepted Gaussian model of earthquake detection might be an artifact of observation.

  8. Spatial contrast sensitivity in clinical neurology.

    PubMed

    Bulens, C; Meerwaldt, J D; van der Wildt, G J; Keemink, C J

    1988-01-01

    We studied contrast sensitivity function in normal subjects and in three illustrative cases with various neurological disorders. This was done by measuring contrast sensitivity over a range of spatial frequencies for vertical sinewave grating stimuli. It is demonstrated that contrast sensitivity function can give information about visual function not obtainable by conventional test procedures.

  9. Analysis of a spatially deconvolved solar pore

    NASA Astrophysics Data System (ADS)

    Quintero Noda, C.; Shimizu, T.; Ruiz Cobo, B.; Suematsu, Y.; Katsukawa, Y.; Ichimoto, K.

    2016-08-01

    Solar pores are active regions with large magnetic field strengths and apparent simple magnetic configurations. Their properties resemble the ones found for the sunspot umbra although pores do not show penumbra. Therefore, solar pores present themselves as an intriguing phenomenon that is not completely understood. We examine in this work a solar pore observed with Hinode/SP using two state of the art techniques. The first one is the spatial deconvolution of the spectropolarimetric data that allows removing the stray light contamination induced by the spatial point spread function of the telescope. The second one is the inversion of the Stokes profiles assuming local thermodynamic equilibrium that let us to infer the atmospheric physical parameters. After applying these techniques, we found that the spatial deconvolution method does not introduce artefacts, even at the edges of the magnetic structure, where large horizontal gradients are detected on the atmospheric parameters. Moreover, we also describe the physical properties of the magnetic structure at different heights finding that, in the inner part of the solar pore, the temperature is lower than outside, the magnetic field strength is larger than 2 kG and unipolar, and the line-of-sight velocity is almost null. At neighbouring pixels, we found low magnetic field strengths of same polarity and strong downward motions that only occur at the low photosphere, below the continuum optical depth log τ = -1. Finally, we studied the spatial relation between different atmospheric parameters at different heights corroborating the physical properties described before.

  10. Centre National d'Etudes Spatiales

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    The Centre National d'Etudes Spatiales (CNES) draws up, proposes and conducts France's space policy. Its role is to develop the uses of space, to meet the civilian and military needs of public bodies and of the scientific community, and to foster the development and dissemination of new applications, designed to create wealth and jobs....

  11. Transient, spatially varied groundwater recharge modeling

    NASA Astrophysics Data System (ADS)

    Assefa, Kibreab Amare; Woodbury, Allan D.

    2013-08-01

    The objective of this work is to integrate field data and modeling tools in producing temporally and spatially varying groundwater recharge in a pilot watershed in North Okanagan, Canada. The recharge modeling is undertaken by using the Richards equation based finite element code (HYDRUS-1D), ArcGIS™, ROSETTA, in situ observations of soil temperature and soil moisture, and a long-term gridded climate data. The public version of HYDUS-1D and another version with detailed freezing and thawing module are first used to simulate soil temperature, snow pack, and soil moisture over a one year experimental period. Statistical analysis of the results show both versions of HYDRUS-1D reproduce observed variables to the same degree. After evaluating model performance using field data and ROSETTA derived soil hydraulic parameters, the HYDRUS-1D code is coupled with ArcGIS™ to produce spatially and temporally varying recharge maps throughout the Deep Creek watershed. Temporal and spatial analysis of 25 years daily recharge results at various representative points across the study watershed reveal significant temporal and spatial variations; average recharge estimated at 77.8 ± 50.8 mm/year. Previous studies in the Okanagan Basin used Hydrologic Evaluation of Landfill Performance without any attempt of model performance evaluation, notwithstanding its inherent limitations. Thus, climate change impact results from this previous study and similar others, such as Jyrkama and Sykes (2007), need to be interpreted with caution.

  12. Coherent interactions of dissipative spatial solitons.

    PubMed

    Ultanir, Erdem A; Stegeman, George I; Lange, Christoph H; Lederer, Falk

    2004-02-01

    We report observation of the interaction between two coherent dissipative spatial solitons in a periodically patterned semiconductor optical amplifier with power levels of tens of milliwatts. The interactions are nonlocal and phase dependent and exhibit surprising features, such as soliton birth. The experimental results are in good agreement with the numerical simulations.

  13. Stable spatial solitons in semiconductor optical amplifiers.

    PubMed

    Ultanir, E A; Michaelis, D; Lederer, F; Stegeman, G I

    2003-02-15

    The existence of stable dissipative spatial solitons at low intensities in patterned electrode semiconductor optical amplifiers (SOAs) is predicted theoretically. In contrast to conventional SOAs, this system may support stable solitons because the inherent saturating losses provide subcritical bifurcations for both the plane-wave and the soliton solution.

  14. Does Face Inversion Change Spatial Frequency Tuning?

    ERIC Educational Resources Information Center

    Willenbockel, Verena; Fiset, Daniel; Chauvin, Alan; Blais, Caroline; Arguin, Martin; Tanaka, James W.; Bub, Daniel N.; Gosselin, Frederic

    2010-01-01

    The authors examined spatial frequency (SF) tuning of upright and inverted face identification using an SF variant of the Bubbles technique (F. Gosselin & P. G. Schyns, 2001). In Experiment 1, they validated the SF Bubbles technique in a plaid detection task. In Experiments 2a-c, the SFs used for identifying upright and inverted inner facial…

  15. Spatial Ability Improvement and Curriculum Content

    ERIC Educational Resources Information Center

    Connolly, Patrick E.

    2009-01-01

    There has been a significant history of research on spatial ability and visualization improvement and related curriculum content presented by members of the Engineering Design Graphics Division over the past decade. Recently, interest in this topic has again been heightened thanks to the work of several division members on research such as the…

  16. Geostatistics and spatial analysis in biological anthropology.

    PubMed

    Relethford, John H

    2008-05-01

    A variety of methods have been used to make evolutionary inferences based on the spatial distribution of biological data, including reconstructing population history and detection of the geographic pattern of natural selection. This article provides an examination of geostatistical analysis, a method used widely in geology but which has not often been applied in biological anthropology. Geostatistical analysis begins with the examination of a variogram, a plot showing the relationship between a biological distance measure and the geographic distance between data points and which provides information on the extent and pattern of spatial correlation. The results of variogram analysis are used for interpolating values of unknown data points in order to construct a contour map, a process known as kriging. The methods of geostatistical analysis and discussion of potential problems are applied to a large data set of anthropometric measures for 197 populations in Ireland. The geostatistical analysis reveals two major sources of spatial variation. One pattern, seen for overall body and craniofacial size, shows an east-west cline most likely reflecting the combined effects of past population dispersal and settlement. The second pattern is seen for craniofacial height and shows an isolation by distance pattern reflecting rapid spatial changes in the midlands region of Ireland, perhaps attributable to the genetic impact of the Vikings. The correspondence of these results with other analyses of these data and the additional insights generated from variogram analysis and kriging illustrate the potential utility of geostatistical analysis in biological anthropology.

  17. Spatially balanced survey designs for natural resources

    EPA Science Inventory

    Ecological resource monitoring programs typically require the use of a probability survey design to select locations or entities to be physically sampled in the field. The ecological resource of interest, the target population, occurs over a spatial domain and the sample selecte...

  18. Spatial part-set cuing facilitation.

    PubMed

    Kelley, Matthew R; Parasiuk, Yuri; Salgado-Benz, Jennifer; Crocco, Megan

    2016-07-01

    Cole, Reysen, and Kelley [2013. Part-set cuing facilitation for spatial information. Journal of Experimental Psychology: Learning, Memory, & Cognition, 39, 1615-1620] reported robust part-set cuing facilitation for spatial information using snap circuits (a colour-coded electronics kit designed for children to create rudimentary circuit boards). In contrast, Drinkwater, Dagnall, and Parker [2006. Effects of part-set cuing on experienced and novice chess players' reconstruction of a typical chess midgame position. Perceptual and Motor Skills, 102(3), 645-653] and Watkins, Schwartz, and Lane [1984. Does part-set cuing test for memory organization? Evidence from reconstructions of chess positions. Canadian Journal of Psychology/Revue Canadienne de Psychologie, 38(3), 498-503] showed no influence of part-set cuing for spatial information when using chess boards. One key difference between the two procedures was that the snap circuit stimuli were explicitly connected to one another, whereas chess pieces were not. Two experiments examined the effects of connection type (connected vs. unconnected) and cue type (cued vs. uncued) on memory for spatial information. Using chess boards (Experiment 1) and snap circuits (Experiment 2), part-set cuing facilitation only occurred when the stimuli were explicitly connected; there was no influence of cuing with unconnected stimuli. These results are potentially consistent with the retrieval strategy disruption hypothesis, as well as the two- and three-mechanism accounts of part-set cuing.

  19. Spatial dynamics of ecological public goods

    PubMed Central

    Wakano, Joe Yuichiro; Nowak, Martin A.; Hauert, Christoph

    2009-01-01

    The production, consumption, and exploitation of common resources ranging from extracellular products in microorganisms to global issues of climate change refer to public goods interactions. Individuals can cooperate and sustain common resources at some cost or defect and exploit the resources without contributing. This generates a conflict of interest, which characterizes social dilemmas: Individual selection favors defectors, but for the community, it is best if everybody cooperates. Traditional models of public goods do not take into account that benefits of the common resource enable cooperators to maintain higher population densities. This leads to a natural feedback between population dynamics and interaction group sizes as captured by “ecological public goods.” Here, we show that the spatial evolutionary dynamics of ecological public goods in “selection-diffusion” systems promotes cooperation based on different types of pattern formation processes. In spatial settings, individuals can migrate (diffuse) to populate new territories. Slow diffusion of cooperators fosters aggregation in highly productive patches (activation), whereas fast diffusion enables defectors to readily locate and exploit these patches (inhibition). These antagonistic forces promote coexistence of cooperators and defectors in static or dynamic patterns, including spatial chaos of ever-changing configurations. The local environment of cooperators and defectors is shaped by the production or consumption of common resources. Hence, diffusion-induced self-organization into spatial patterns not only enhances cooperation but also provides simple mechanisms for the spontaneous generation of habitat diversity, which denotes a crucial determinant of the viability of ecological systems. PMID:19416839

  20. Spatial Categories and the Estimation of Location

    ERIC Educational Resources Information Center

    Huttenlocher, Janellen; Hedges, Larry V.; Corrigan, Bryce; Crawford, L. Elizabeth

    2004-01-01

    Four experiments are reported in which people organize a space hierarchically when they estimate particular locations in that space. Earlier work showed that people subdivide circles into quadrants bounded at the vertical and horizontal axes, biasing their estimates towards prototypical diagonal locations within those spatial categories…

  1. Gesture Supports Spatial Thinking in STEM

    ERIC Educational Resources Information Center

    Stieff, Mike; Lira, Matthew E.; Scopelitis, Stephanie A.

    2016-01-01

    The present article describes two studies that examine the impact of teaching students to use gesture to support spatial thinking in the Science, Technology, Engineering, and Mathematics (STEM) discipline of chemistry. In Study 1 we compared the effectiveness of instruction that involved either watching gesture, reproducing gesture, or reading…

  2. PREDICTION OF NONLINEAR SPATIAL FUNCTIONALS. (R827257)

    EPA Science Inventory

    Spatial statistical methodology can be useful in the arena of environmental regulation. Some regulatory questions may be addressed by predicting linear functionals of the underlying signal, but other questions may require the prediction of nonlinear functionals of the signal. ...

  3. Productive Taboos: Cultivating Spatialized Literacy Practices

    ERIC Educational Resources Information Center

    Vander Zanden, Sarah

    2015-01-01

    The fifth grade students in this project were part of a yearlong ethnographic study in an urban elementary school. They engaged in a student initiated inquiry project combining bakeries and mysteries, which culminated in the production of an original film. Situated in a socio-spatialized stance on literacy involving networks of participation and…

  4. Spatial Attention Modulates the Precedence Effect

    ERIC Educational Resources Information Center

    London, Sam; Bishop, Christopher W.; Miller, Lee M.

    2012-01-01

    Communication and navigation in real environments rely heavily on the ability to distinguish objects in acoustic space. However, auditory spatial information is often corrupted by conflicting cues and noise such as acoustic reflections. Fortunately the brain can apply mechanisms at multiple levels to emphasize target information and mitigate such…

  5. Encoding Modality and Spatial Memory Retrieval

    ERIC Educational Resources Information Center

    Tlauka, Michael; Clark, C. Richard; Liu, Ping; Conway, Marie

    2009-01-01

    This study examined the temporal characteristics of event-related brain electrical activity associated with the processing of spatial memories derived from linguistic and tactile information. Participants learned a map by (1) reading a text description of the map, (2) touching a wooden topological representation of the map (hidden from view), or…

  6. Spatial Working Memory Deficits in Autism

    ERIC Educational Resources Information Center

    Steele, Shelly D.; Minshew, Nancy J.; Luna, Beatriz; Sweeney, John A.

    2007-01-01

    Previous studies have reported working memory deficits in autism, but this finding has been inconsistent. One possibility is that deficits in this domain may be present only when working memory load exceeds some limited capacity. High-functioning individuals with autism performed the CANTAB computerized test of spatial working memory. Individuals…

  7. Spatial ascariasis risk estimation using socioeconomic variables.

    PubMed

    Valencia, Luis Iván Ortiz; Fortes, Bruno de Paula Menezes Drumond; Medronho, Roberto de Andrade

    2005-12-01

    Frequently, disease incidence is mapped as area data, for example, census tracts, districts or states. Spatial disease incidence can be highly heterogeneous inside these areas. Ascariasis is a highly prevalent disease, which is associated with poor sanitation and hygiene. Geostatistics was applied to model spatial distribution of Ascariasis risk and socioeconomic risk events in a poor community in Rio de Janeiro, Brazil. Data were gathered from a coproparasitologic and a domiciliary survey in 1550 children aged 1-9. Ascariasis risk and socioeconomic risk events were spatially estimated using Indicator Kriging. Cokriging models with a Linear Model of Coregionalization incorporating one socioeconomic variable were implemented. If a housewife attended school for less than four years, the non-use of a home water filter, a household density greater than one, and a household income lower than one Brazilian minimum wage increased the risk of Ascariasis. Cokriging improved spatial estimation of Ascariasis risk areas when compared to Indicator Kriging and detected more Ascariasis very-high risk areas than the GIS Overlay method.

  8. When Symbolic Spatial Cues Go before Numbers

    ERIC Educational Resources Information Center

    Herrera, Amparo; Macizo, Pedro

    2011-01-01

    This work explores the effect of spatial cueing on number processing. Participants performed a parity judgment task. However, shortly before the target number, a cue (arrow pointing to left, arrow pointing to right or a cross) was centrally presented. In Experiment 1, in which responses were lateralized, the cue direction modulated the interaction…

  9. Visual and Spatial Modes in Science Learning

    ERIC Educational Resources Information Center

    Ramadas, Jayashree

    2009-01-01

    This paper surveys some major trends from research on visual and spatial thinking coming from cognitive science, developmental psychology, science literacy, and science studies. It explores the role of visualisation in creativity, in building mental models, and in the communication of scientific ideas, in order to place these findings in the…

  10. The Effect of Barriers on Spatial Representations.

    ERIC Educational Resources Information Center

    Cohen, Robert; Weatherford, David L.

    1981-01-01

    Examined children's recall of the spatial configurations of an environment after the children followed prearranged paths and encountered barriers to movement. When asked to reconstruct the environmental configuration from memory, males estimated distances more accurately than did females. No age differences were noted. (Author/DB)

  11. Fiber transport of spatially entangled photons

    NASA Astrophysics Data System (ADS)

    Löffler, W.; Eliel, E. R.; Woerdman, J. P.; Euser, T. G.; Scharrer, M.; Russell, P.

    2012-03-01

    High-dimensional entangled photons pairs are interesting for quantum information and cryptography: Compared to the well-known 2D polarization case, the stronger non-local quantum correlations could improve noise resistance or security, and the larger amount of information per photon increases the available bandwidth. One implementation is to use entanglement in the spatial degree of freedom of twin photons created by spontaneous parametric down-conversion, which is equivalent to orbital angular momentum entanglement, this has been proven to be an excellent model system. The use of optical fiber technology for distribution of such photons has only very recently been practically demonstrated and is of fundamental and applied interest. It poses a big challenge compared to the established time and frequency domain methods: For spatially entangled photons, fiber transport requires the use of multimode fibers, and mode coupling and intermodal dispersion therein must be minimized not to destroy the spatial quantum correlations. We demonstrate that these shortcomings of conventional multimode fibers can be overcome by using a hollow-core photonic crystal fiber, which follows the paradigm to mimic free-space transport as good as possible, and are able to confirm entanglement of the fiber-transported photons. Fiber transport of spatially entangled photons is largely unexplored yet, therefore we discuss the main complications, the interplay of intermodal dispersion and mode mixing, the influence of external stress and core deformations, and consider the pros and cons of various fiber types.

  12. Sampling design optimization for spatial functions

    USGS Publications Warehouse

    Olea, R.A.

    1984-01-01

    A new procedure is presented for minimizing the sampling requirements necessary to estimate a mappable spatial function at a specified level of accuracy. The technique is based on universal kriging, an estimation method within the theory of regionalized variables. Neither actual implementation of the sampling nor universal kriging estimations are necessary to make an optimal design. The average standard error and maximum standard error of estimation over the sampling domain are used as global indices of sampling efficiency. The procedure optimally selects those parameters controlling the magnitude of the indices, including the density and spatial pattern of the sample elements and the number of nearest sample elements used in the estimation. As an illustration, the network of observation wells used to monitor the water table in the Equus Beds of Kansas is analyzed and an improved sampling pattern suggested. This example demonstrates the practical utility of the procedure, which can be applied equally well to other spatial sampling problems, as the procedure is not limited by the nature of the spatial function. ?? 1984 Plenum Publishing Corporation.

  13. Decomposing Solids to Develop Spatial Sense

    ERIC Educational Resources Information Center

    Obara, Samuel

    2009-01-01

    Three sets of activities are presented in the form of puzzles. These activities focus on students' investigations of three-dimensional models, observing how they look and feel. The improvement of students' spatial sense and conceptual understanding after experiencing the activities is described. (Contains 15 figures.)

  14. Exploiting spatial descriptions in visual scene analysis.

    PubMed

    Ziegler, Leon; Johannsen, Katrin; Swadzba, Agnes; De Ruiter, Jan P; Wachsmuth, Sven

    2012-08-01

    The reliable automatic visual recognition of indoor scenes with complex object constellations using only sensor data is a nontrivial problem. In order to improve the construction of an accurate semantic 3D model of an indoor scene, we exploit human-produced verbal descriptions of the relative location of pairs of objects. This requires the ability to deal with different spatial reference frames (RF) that humans use interchangeably. In German, both the intrinsic and relative RF are used frequently, which often leads to ambiguities in referential communication. We assume that there are certain regularities that help in specific contexts. In a first experiment, we investigated how speakers of German describe spatial relationships between different pieces of furniture. This gave us important information about the distribution of the RFs used for furniture-predicate combinations, and by implication also about the preferred spatial predicate. The results of this experiment are compiled into a computational model that extracts partial orderings of spatial arrangements between furniture items from verbal descriptions. In the implemented system, the visual scene is initially scanned by a 3D camera system. From the 3D point cloud, we extract point clusters that suggest the presence of certain furniture objects. We then integrate the partial orderings extracted from the verbal utterances incrementally and cumulatively with the estimated probabilities about the identity and location of objects in the scene, and also estimate the probable orientation of the objects. This allows the system to significantly improve both the accuracy and richness of its visual scene representation.

  15. Spatial Learning and Computer Simulations in Science

    ERIC Educational Resources Information Center

    Lindgren, Robb; Schwartz, Daniel L.

    2009-01-01

    Interactive simulations are entering mainstream science education. Their effects on cognition and learning are often framed by the legacy of information processing, which emphasized amodal problem solving and conceptual organization. In contrast, this paper reviews simulations from the vantage of research on perception and spatial learning,…

  16. When and How Are Spatial Perceptions Scaled?

    ERIC Educational Resources Information Center

    Witt, Jessica K.; Proffitt, Dennis R.; Epstein, William

    2010-01-01

    This research was designed to test the predictions of 2 approaches to perception. By most traditional accounts, people are thought to derive general-purpose spatial perceptions that are scaled in arbitrary, unspecified units. In contrast, action-specific approaches propose that the angular information inherent in optic flow and ocular-motor…

  17. Flexible Visual Processing of Spatial Relationships

    ERIC Educational Resources Information Center

    Franconeri, Steven L.; Scimeca, Jason M.; Roth, Jessica C.; Helseth, Sarah A.; Kahn, Lauren E.

    2012-01-01

    Visual processing breaks the world into parts and objects, allowing us not only to examine the pieces individually, but also to perceive the relationships among them. There is work exploring how we perceive spatial relationships within structures with existing representations, such as faces, common objects, or prototypical scenes. But strikingly,…

  18. Spatial population structure of Yellowstone bison

    USGS Publications Warehouse

    Olexa, E.M.; Gogan, P.J.P.

    2007-01-01

    Increases in Yellowstone National Park, USA, bison (Bison bison) numbers and shifts in seasonal distribution have resulted in more frequent movements of bison beyond park boundaries and development of an interagency management plan for the Yellowstone bison population. Implementation of the plan under the adaptive management paradigm requires an understanding of the spatial and temporal structure of the population. We used polythetic agglomerative hierarchical cluster analysis of radiolocations obtained from free-ranging bison to investigate seasonal movements and aggregations. We classified radiolocations into 4 periods: annual, peak rut (15 Jul-15 Sep), extended rut (1 Jun-31 Oct), and winter (1 Nov-31 May). We documented spatial separation of Yellowstone bison into 2 segments, the northern and central herds, during all periods. The estimated year-round exchange rate (4.85-5.83%) of instrumented bison varied with the fusion strategy employed. We did not observe exchange between the 2 segments during the peak rut and it varied during the extended rut (2.15-3.23%). We estimated a winter exchange of 4.85-7.77%. The outcome and effectiveness of management actions directed at Yellowstone bison may be affected by spatial segregation and herd affinity within the population. Reductions based on total population size, but not applied to the entire population, may adversely affect one herd while having little effect on the other. Similarly, management actions targeting a segment of the population may benefit from the spatial segregation exhibited.

  19. Quasi-likelihood for Spatial Point Processes

    PubMed Central

    Guan, Yongtao; Jalilian, Abdollah; Waagepetersen, Rasmus

    2014-01-01

    Summary Fitting regression models for intensity functions of spatial point processes is of great interest in ecological and epidemiological studies of association between spatially referenced events and geographical or environmental covariates. When Cox or cluster process models are used to accommodate clustering not accounted for by the available covariates, likelihood based inference becomes computationally cumbersome due to the complicated nature of the likelihood function and the associated score function. It is therefore of interest to consider alternative more easily computable estimating functions. We derive the optimal estimating function in a class of first-order estimating functions. The optimal estimating function depends on the solution of a certain Fredholm integral equation which in practise is solved numerically. The derivation of the optimal estimating function has close similarities to the derivation of quasi-likelihood for standard data sets. The approximate solution is further equivalent to a quasi-likelihood score for binary spatial data. We therefore use the term quasi-likelihood for our optimal estimating function approach. We demonstrate in a simulation study and a data example that our quasi-likelihood method for spatial point processes is both statistically and computationally efficient. PMID:26041970

  20. On Developing Students' Spatial Visualisation Ability

    ERIC Educational Resources Information Center

    Risma, Dwi Afrini; Putri, Ratu Ilma Indra; Hartono, Yusuf

    2013-01-01

    This research aims at studying on how students develop their spatial visualisation abilities. In this paper, one of five activities in an ongoing classroom activity is discussed. This paper documents students' learning activity in exploring the building blocks. The goal of teaching experiment is to support the development of students' spatial…

  1. Spatial Visualization by Realistic 3D Views

    ERIC Educational Resources Information Center

    Yue, Jianping

    2008-01-01

    In this study, the popular Purdue Spatial Visualization Test-Visualization by Rotations (PSVT-R) in isometric drawings was recreated with CAD software that allows 3D solid modeling and rendering to provide more realistic pictorial views. Both the original and the modified PSVT-R tests were given to students and their scores on the two tests were…

  2. Spatial Training Improves Children's Mathematics Ability

    ERIC Educational Resources Information Center

    Cheng, Yi-Ling; Mix, Kelly S.

    2014-01-01

    We tested whether mental rotation training improved math performance in 6- to 8-year-olds. Children were pretested on a range of number and math skills. Then one group received a single session of mental rotation training using an object completion task that had previously improved spatial ability in children this age (Ehrlich, Levine, &…

  3. Window Presentation Styles and User's Spatial Ability.

    ERIC Educational Resources Information Center

    Bastecki, Victoria L.; Berry, Louis H.

    The purpose of this study was to examine the effects of spatial ability level and window presentation style of tiled and overlapped computer displays on the achievement of dental hygiene students. Participants were 43 first-term Dental Hygiene students enrolled full-time at a University School of Dental Medicine. Phase one of this project…

  4. [The Brazilian population: demographic and spatial dynamics].

    PubMed

    Bret, B; Le Gauffey, Y; Thery, H; Waniez, P

    1984-01-01

    Recent demographic trends in Brazil are reviewed. A continuing decline in fertility is noted as the demographic transition proceeds. The differences by region and between rural and urban areas are considered. Attention is also paid to differences in spatial distribution and to internal migration.

  5. Got LEGO Bricks? Children with Spatial Strengths

    ERIC Educational Resources Information Center

    Mann, Rebecca

    2013-01-01

    Individuals with spatial strengths have preferences for visual ideation, holistic reasoning, and innovation. With the emphasis on verbal skills, American schools rarely provide opportunities for children to excel in these areas. Standardized assessments used to judge achievement do not value reflective thinking and innovation; therefore, students…

  6. Modified Navigation Instructions for Spatial Navigation Assistance Systems Lead to Incidental Spatial Learning

    PubMed Central

    Gramann, Klaus; Hoepner, Paul; Karrer-Gauss, Katja

    2017-01-01

    Spatial cognitive skills deteriorate with the increasing use of automated GPS navigation and a general decrease in the ability to orient in space might have further impact on independence, autonomy, and quality of life. In the present study we investigate whether modified navigation instructions support incidental spatial knowledge acquisition. A virtual driving environment was used to examine the impact of modified navigation instructions on spatial learning while using a GPS navigation assistance system. Participants navigated through a simulated urban and suburban environment, using navigation support to reach their destination. Driving performance as well as spatial learning was thereby assessed. Three navigation instruction conditions were tested: (i) a control group that was provided with classical navigation instructions at decision points, and two other groups that received navigation instructions at decision points including either (ii) additional irrelevant information about landmarks or (iii) additional personally relevant information (i.e., individual preferences regarding food, hobbies, etc.), associated with landmarks. Driving performance revealed no differences between navigation instructions. Significant improvements were observed in both modified navigation instruction conditions on three different measures of spatial learning and memory: subsequent navigation of the initial route without navigation assistance, landmark recognition, and sketch map drawing. Future navigation assistance systems could incorporate modified instructions to promote incidental spatial learning and to foster more general spatial cognitive abilities. Such systems might extend mobility across the lifespan. PMID:28243219

  7. Minimizing Spatial Variability of Healthcare Spatial Accessibility—The Case of a Dengue Fever Outbreak

    PubMed Central

    Chu, Hone-Jay; Lin, Bo-Cheng; Yu, Ming-Run; Chan, Ta-Chien

    2016-01-01

    Outbreaks of infectious diseases or multi-casualty incidents have the potential to generate a large number of patients. It is a challenge for the healthcare system when demand for care suddenly surges. Traditionally, valuation of heath care spatial accessibility was based on static supply and demand information. In this study, we proposed an optimal model with the three-step floating catchment area (3SFCA) to account for the supply to minimize variability in spatial accessibility. We used empirical dengue fever outbreak data in Tainan City, Taiwan in 2015 to demonstrate the dynamic change in spatial accessibility based on the epidemic trend. The x and y coordinates of dengue-infected patients with precision loss were provided publicly by the Tainan City government, and were used as our model’s demand. The spatial accessibility of heath care during the dengue outbreak from August to October 2015 was analyzed spatially and temporally by producing accessibility maps, and conducting capacity change analysis. This study also utilized the particle swarm optimization (PSO) model to decrease the spatial variation in accessibility and shortage areas of healthcare resources as the epidemic went on. The proposed method in this study can help decision makers reallocate healthcare resources spatially when the ratios of demand and supply surge too quickly and form clusters in some locations. PMID:27983611

  8. Modified Navigation Instructions for Spatial Navigation Assistance Systems Lead to Incidental Spatial Learning.

    PubMed

    Gramann, Klaus; Hoepner, Paul; Karrer-Gauss, Katja

    2017-01-01

    Spatial cognitive skills deteriorate with the increasing use of automated GPS navigation and a general decrease in the ability to orient in space might have further impact on independence, autonomy, and quality of life. In the present study we investigate whether modified navigation instructions support incidental spatial knowledge acquisition. A virtual driving environment was used to examine the impact of modified navigation instructions on spatial learning while using a GPS navigation assistance system. Participants navigated through a simulated urban and suburban environment, using navigation support to reach their destination. Driving performance as well as spatial learning was thereby assessed. Three navigation instruction conditions were tested: (i) a control group that was provided with classical navigation instructions at decision points, and two other groups that received navigation instructions at decision points including either (ii) additional irrelevant information about landmarks or (iii) additional personally relevant information (i.e., individual preferences regarding food, hobbies, etc.), associated with landmarks. Driving performance revealed no differences between navigation instructions. Significant improvements were observed in both modified navigation instruction conditions on three different measures of spatial learning and memory: subsequent navigation of the initial route without navigation assistance, landmark recognition, and sketch map drawing. Future navigation assistance systems could incorporate modified instructions to promote incidental spatial learning and to foster more general spatial cognitive abilities. Such systems might extend mobility across the lifespan.

  9. Spatial network surrogates for disentangling complex system structure from spatial embedding of nodes

    NASA Astrophysics Data System (ADS)

    Wiedermann, Marc; Donges, Jonathan F.; Kurths, Jürgen; Donner, Reik V.

    2016-04-01

    Networks with nodes embedded in a metric space have gained increasing interest in recent years. The effects of spatial embedding on the networks' structural characteristics, however, are rarely taken into account when studying their macroscopic properties. Here, we propose a hierarchy of null models to generate random surrogates from a given spatially embedded network that can preserve certain global and local statistics associated with the nodes' embedding in a metric space. Comparing the original network's and the resulting surrogates' global characteristics allows one to quantify to what extent these characteristics are already predetermined by the spatial embedding of the nodes and links. We apply our framework to various real-world spatial networks and show that the proposed models capture macroscopic properties of the networks under study much better than standard random network models that do not account for the nodes' spatial embedding. Depending on the actual performance of the proposed null models, the networks are categorized into different classes. Since many real-world complex networks are in fact spatial networks, the proposed approach is relevant for disentangling the underlying complex system structure from spatial embedding of nodes in many fields, ranging from social systems over infrastructure and neurophysiology to climatology.

  10. Highly accurate spatial mode generation using spatial cross modulation method for mode division multiplexing

    NASA Astrophysics Data System (ADS)

    Sakuma, Hiroki; Okamoto, Atsushi; Shibukawa, Atsushi; Goto, Yuta; Tomita, Akihisa

    2016-02-01

    We propose a spatial mode generation technology using spatial cross modulation (SCM) for mode division multiplexing (MDM). The most well-known method for generating arbitrary complex amplitude fields is to display an off-axis computer-generated hologram (CGH) on a spatial light modulator (SLM). However, in this method, a desired complex amplitude field is obtained with first order diffraction light. This critically lowers the light utilization efficiency. On the other hand, in the SCM, the desired complex field is provided with zeroth order diffraction light. For this reason, our technology can generate spatial modes with large light utilization efficiency in addition to high accuracy. In this study, first, a numerical simulation was performed to verify that the SCM is applicable for spatial mode generation. Next, we made a comparison from two view points of the coupling efficiency and the light utilization between our technology and the technology using an off-axis amplitude hologram as a representative complex amplitude generation method. The simulation results showed that our technology can achieve considerably high light utilization efficiency while maintaining the enough coupling efficiency comparable to the technology using an off-axis amplitude hologram. Finally, we performed an experiment on spatial modes generation using the SCM. Experimental results showed that our technology has the great potential to realize the spatial mode generation with high accuracy.

  11. Spatial variation in the charcoal pool

    NASA Astrophysics Data System (ADS)

    Ohlson, M.; Bjune, A. E.; Kasin, I.; Nordtug Wist, A.

    2012-04-01

    Mikael Ohlson, Anne E. Bjune, Isabella Kasin and Anveig Nordtug Wist It is well known that the soil charcoal pool varies significantly in size across different types of forest landscapes and regional climates. However, the level of variation on fine spatial scales within a given forest landscape remains poorly known. Here we use a geostatistical approach to describe the spatial structure and variability of the soil charcoal pool in a boreal forest landscape. Our study landscape is a watershed including a small lake and two distinct types of forests, viz. Norway spruce (Picea abies) and Scots pine (Pinus sylvestris) forests. The study is based on 200 forest soil cores and one lake sediment core in which the amount of macroscopic charcoal was measured. The amount of charcoal in the forest soil cores was very variable and ranged from 0 to 3600 g per square meter. The variation was profound also on fine spatial scales, i.e. 0.05 - 0.2 m, and geostatistical analysis revealed only weak spatial structuring on scales from 0.05 up to 200 m. Although weak spatial structuring, there were three significant and general patterns in the soil charcoal pool. First, there was a positive relationship between the amount of charcoal in the soil and the density of the contemporary forest. Second, there was more charcoal in the spruce forest than in the pine forest. Third, the amount of charcoal in the soil increased with increasing distance from the lake. The lake sediment core, which had a depth of 3 m and an age of 11 000 years, recorded a continuous influx of macroscopic charcoal throughout the Holocene. Interestingly, the amount of charcoal in the lake sediment exceeded that in the majority of the forest soil cores, indicating a relatively high degradation rate of charcoal in the forest soil and that charcoal is well preserved in the lake sediment.

  12. Frames of reference in spatial language acquisition.

    PubMed

    Shusterman, Anna; Li, Peggy

    2016-08-01

    Languages differ in how they encode spatial frames of reference. It is unknown how children acquire the particular frame-of-reference terms in their language (e.g., left/right, north/south). The present paper uses a word-learning paradigm to investigate 4-year-old English-speaking children's acquisition of such terms. In Part I, with five experiments, we contrasted children's acquisition of novel word pairs meaning left-right and north-south to examine their initial hypotheses and the relative ease of learning the meanings of these terms. Children interpreted ambiguous spatial terms as having environment-based meanings akin to north and south, and they readily learned and generalized north-south meanings. These studies provide the first direct evidence that children invoke geocentric representations in spatial language acquisition. However, the studies leave unanswered how children ultimately acquire "left" and "right." In Part II, with three more experiments, we investigated why children struggle to master body-based frame-of-reference words. Children successfully learned "left" and "right" when the novel words were systematically introduced on their own bodies and extended these words to novel (intrinsic and relative) uses; however, they had difficulty learning to talk about the left and right sides of a doll. This difficulty was paralleled in identifying the left and right sides of the doll in a non-linguistic memory task. In contrast, children had no difficulties learning to label the front and back sides of a doll. These studies begin to paint a detailed account of the acquisition of spatial terms in English, and provide insights into the origins of diverse spatial reference frames in the world's languages.

  13. Spatial Stream Segregation by Auditory Cortical Neurons

    PubMed Central

    Bremen, Peter

    2013-01-01

    In a complex auditory scene, a “cocktail party” for example, listeners can disentangle multiple competing sequences of sounds. A recent psychophysical study in our laboratory demonstrated a robust spatial component of stream segregation showing ∼8° acuity. Here, we recorded single- and multiple-neuron responses from the primary auditory cortex of anesthetized cats while presenting interleaved sound sequences that human listeners would experience as segregated streams. Sequences of broadband sounds alternated between pairs of locations. Neurons synchronized preferentially to sounds from one or the other location, thereby segregating competing sound sequences. Neurons favoring one source location or the other tended to aggregate within the cortex, suggestive of modular organization. The spatial acuity of stream segregation was as narrow as ∼10°, markedly sharper than the broad spatial tuning for single sources that is well known in the literature. Spatial sensitivity was sharpest among neurons having high characteristic frequencies. Neural stream segregation was predicted well by a parameter-free model that incorporated single-source spatial sensitivity and a measured forward-suppression term. We found that the forward suppression was not due to post discharge adaptation in the cortex and, therefore, must have arisen in the subcortical pathway or at the level of thalamocortical synapses. A linear-classifier analysis of single-neuron responses to rhythmic stimuli like those used in our psychophysical study yielded thresholds overlapping those of human listeners. Overall, the results indicate that the ascending auditory system does the work of segregating auditory streams, bringing them to discrete modules in the cortex for selection by top-down processes. PMID:23825404

  14. Spatially explicit modeling in ecology: A review

    USGS Publications Warehouse

    DeAngelis, Donald L.; Yurek, Simeon

    2017-01-01

    The use of spatially explicit models (SEMs) in ecology has grown enormously in the past two decades. One major advancement has been that fine-scale details of landscapes, and of spatially dependent biological processes, such as dispersal and invasion, can now be simulated with great precision, due to improvements in computer technology. Many areas of modeling have shifted toward a focus on capturing these fine-scale details, to improve mechanistic understanding of ecosystems. However, spatially implicit models (SIMs) have played a dominant role in ecology, and arguments have been made that SIMs, which account for the effects of space without specifying spatial positions, have an advantage of being simpler and more broadly applicable, perhaps contributing more to understanding. We address this debate by comparing SEMs and SIMs in examples from the past few decades of modeling research. We argue that, although SIMs have been the dominant approach in the incorporation of space in theoretical ecology, SEMs have unique advantages for addressing pragmatic questions concerning species populations or communities in specific places, because local conditions, such as spatial heterogeneities, organism behaviors, and other contingencies, produce dynamics and patterns that usually cannot be incorporated into simpler SIMs. SEMs are also able to describe mechanisms at the local scale that can create amplifying positive feedbacks at that scale, creating emergent patterns at larger scales, and therefore are important to basic ecological theory. We review the use of SEMs at the level of populations, interacting populations, food webs, and ecosystems and argue that SEMs are not only essential in pragmatic issues, but must play a role in the understanding of causal relationships on landscapes.

  15. Spatial analyses of wildlife contact networks

    PubMed Central

    Davis, Stephen; Abbasi, Babak; Shah, Shrupa; Telfer, Sandra; Begon, Mike

    2015-01-01

    Datasets from which wildlife contact networks of epidemiological importance can be inferred are becoming increasingly common. A largely unexplored facet of these data is finding evidence of spatial constraints on who has contact with whom, despite theoretical epidemiologists having long realized spatial constraints can play a critical role in infectious disease dynamics. A graph dissimilarity measure is proposed to quantify how close an observed contact network is to being purely spatial whereby its edges are completely determined by the spatial arrangement of its nodes. Statistical techniques are also used to fit a series of mechanistic models for contact rates between individuals to the binary edge data representing presence or absence of observed contact. These are the basis for a second measure that quantifies the extent to which contacts are being mediated by distance. We apply these methods to a set of 128 contact networks of field voles (Microtus agrestis) inferred from mark–recapture data collected over 7 years and from four sites. Large fluctuations in vole abundance allow us to demonstrate that the networks become increasingly similar to spatial proximity graphs as vole density increases. The average number of contacts, , was (i) positively correlated with vole density across the range of observed densities and (ii) for two of the four sites a saturating function of density. The implications for pathogen persistence in wildlife may be that persistence is relatively unaffected by fluctuations in host density because at low density is low but hosts move more freely, and at high density is high but transmission is hampered by local build-up of infected or recovered animals. PMID:25411407

  16. Spatial analyses of wildlife contact networks.

    PubMed

    Davis, Stephen; Abbasi, Babak; Shah, Shrupa; Telfer, Sandra; Begon, Mike

    2015-01-06

    Datasets from which wildlife contact networks of epidemiological importance can be inferred are becoming increasingly common. A largely unexplored facet of these data is finding evidence of spatial constraints on who has contact with whom, despite theoretical epidemiologists having long realized spatial constraints can play a critical role in infectious disease dynamics. A graph dissimilarity measure is proposed to quantify how close an observed contact network is to being purely spatial whereby its edges are completely determined by the spatial arrangement of its nodes. Statistical techniques are also used to fit a series of mechanistic models for contact rates between individuals to the binary edge data representing presence or absence of observed contact. These are the basis for a second measure that quantifies the extent to which contacts are being mediated by distance. We apply these methods to a set of 128 contact networks of field voles (Microtus agrestis) inferred from mark-recapture data collected over 7 years and from four sites. Large fluctuations in vole abundance allow us to demonstrate that the networks become increasingly similar to spatial proximity graphs as vole density increases. The average number of contacts, 〈k〉, was (i) positively correlated with vole density across the range of observed densities and (ii) for two of the four sites a saturating function of density. The implications for pathogen persistence in wildlife may be that persistence is relatively unaffected by fluctuations in host density because at low density 〈k〉 is low but hosts move more freely, and at high density 〈k〉 is high but transmission is hampered by local build-up of infected or recovered animals.

  17. Effects of hunting on cougar spatial organization.

    PubMed

    Maletzke, Benjamin T; Wielgus, Robert; Koehler, Gary M; Swanson, Mark; Cooley, Hilary; Alldredge, J Richard

    2014-06-01

    The effects of increased mortality on the spatial dynamics of solitary carnivores are not well understood. We examined the spatial ecology of two cougar populations that differed in hunting intensity to test whether increased mortality affected home range size and overlap. The stability hypothesis predicts that home range size and overlap will be similar for both sexes among the two areas. The instability hypothesis predicts that home range size and overlap will be greater in the heavily hunted population, although may differ for males versus females due to behavior strategies. We marked 22 adult resident cougars in the lightly hunted population and 20 in the heavily hunted population with GPS collars from 2002 to 2008. Cougar densities and predation rates were similar among areas, suggesting no difference in per capita resources. We compared home range size, two-dimensional home range overlap, and three-dimensional utilization distribution overlap index (UDOI) among annual home ranges for male and female cougars. Male cougars in the heavily hunted area had larger sized home ranges and greater two-dimensional and three-dimensional UDOI overlap than those in the lightly hunted area. Females showed no difference in size and overlap of home range areas between study populations - further suggesting that differences in prey quantity and distribution between study areas did not explain differences in male spatial organization. We reject the spatial stability hypothesis and provide evidence to support the spatial instability hypothesis. Increased hunting and ensuing increased male home range size and overlap may result in negative demographic effects for cougars and potential unintended consequences for managers.

  18. Emotional stimuli capture spatial attention but do not modulate spatial memory.

    PubMed

    Bannerman, Rachel L; Temminck, Elisha V; Sahraie, Arash

    2012-07-15

    There is evidence that emotional stimuli capture spatial attention and that visual memory is enhanced for emotional content. Here we examine the relationship between emotional content of stimuli and interactions with spatial memory. To assess spatial memory, a modified version of the Corsi Blocks Task (CBT), utilising emotional stimuli, was employed. In the CBT a series of spatial positions are highlighted and the participant has to repeat these in the order in which they were produced. Results showed that presenting more meaningful stimuli, such as emotional faces (e.g. angry or happy) at the spatial locations in the CBT did not enhance spatial memory span relative to the presentation of neutral stimuli (e.g. neutral faces) or non-image stimuli signified by a change in the luminance of the blocks. In addition, saccadic eye movements performed during retention disrupted spatial memory for all items. This occurred irrespective of whether the item to be remembered was a face, a luminance-defined stimulus or whether the face carried emotional significance. The results were not related to the visibility of the test stimuli as participants recognised the emotion displayed by the faces significantly above chance and rated emotional faces as being more arousing than neutral faces. Changes in the type of emotional stimulus (e.g. fearful faces, emotional schematic faces, spiders or flowers) or encoding (short vs. long) duration did not alter the pattern of results. These findings demonstrate an important dissociation between spatial capture and memory. Although emotional content can modulate orienting behaviour, it appears to be of limited effect on spatial memory.

  19. Is attention based on spatial contextual memory preferentially guided by low spatial frequency signals?

    PubMed

    Patai, Eva Zita; Buckley, Alice; Nobre, Anna Christina

    2013-01-01

    A popular model of visual perception states that coarse information (carried by low spatial frequencies) along the dorsal stream is rapidly transmitted to prefrontal and medial temporal areas, activating contextual information from memory, which can in turn constrain detailed input carried by high spatial frequencies arriving at a slower rate along the ventral visual stream, thus facilitating the processing of ambiguous visual stimuli. We were interested in testing whether this model contributes to memory-guided orienting of attention. In particular, we asked whether global, low-spatial frequency (LSF) inputs play a dominant role in triggering contextual memories in order to facilitate the processing of the upcoming target stimulus. We explored this question over four experiments. The first experiment replicated the LSF advantage reported in perceptual discrimination tasks by showing that participants were faster and more accurate at matching a low spatial frequency version of a scene, compared to a high spatial frequency version, to its original counterpart in a forced-choice task. The subsequent three experiments tested the relative contributions of low versus high spatial frequencies during memory-guided covert spatial attention orienting tasks. Replicating the effects of memory-guided attention, pre-exposure to scenes associated with specific spatial memories for target locations (memory cues) led to higher perceptual discrimination and faster response times to identify targets embedded in the scenes. However, either high or low spatial frequency cues were equally effective; LSF signals did not selectively or preferentially contribute to the memory-driven attention benefits to performance. Our results challenge a generalized model that LSFs activate contextual memories, which in turn bias attention and facilitate perception.

  20. Age-related similarities and differences in monitoring spatial cognition.

    PubMed

    Ariel, Robert; Moffat, Scott D

    2017-03-31

    Spatial cognitive performance is impaired in later adulthood but it is unclear whether the metacognitive processes involved in monitoring spatial cognitive performance are also compromised. Inaccurate monitoring could affect whether people choose to engage in tasks that require spatial thinking and also the strategies they use in spatial domains such as navigation. The current experiment examined potential age differences in monitoring spatial cognitive performance in a variety of spatial domains including visual-spatial working memory, spatial orientation, spatial visualization, navigation, and place learning. Younger and older adults completed a 2D mental rotation test, 3D mental rotation test, paper folding test, spatial memory span test, two virtual navigation tasks, and a cognitive mapping test. Participants also made metacognitive judgments of performance (confidence judgments, judgments of learning, or navigation time estimates) on each trial for all spatial tasks. Preference for allocentric or egocentric navigation strategies was also measured. Overall, performance was poorer and confidence in performance was lower for older adults than younger adults. In most spatial domains, the absolute and relative accuracy of metacognitive judgments was equivalent for both age groups. However, age differences in monitoring accuracy (specifically relative accuracy) emerged in spatial tasks involving navigation. Confidence in navigating for a target location also mediated age differences in allocentric navigation strategy use. These findings suggest that with the possible exception of navigation monitoring, spatial cognition may be spared from age-related decline even though spatial cognition itself is impaired in older age.