Two-Step Optimization for Spatial Accessibility Improvement: A Case Study of Health Care Planning in Rural China

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Jing Luo

2017-01-01

Full Text Available A recent advancement in location-allocation modeling formulates a two-step approach to a new problem of minimizing disparity of spatial accessibility. Our field work in a health care planning project in a rural county in China indicated that residents valued distance or travel time from the nearest hospital foremost and then considered quality of care including less waiting time as a secondary desirability. Based on the case study, this paper further clarifies the sequential decision-making approach, termed “two-step optimization for spatial accessibility improvement (2SO4SAI.” The first step is to find the best locations to site new facilities by emphasizing accessibility as proximity to the nearest facilities with several alternative objectives under consideration. The second step adjusts the capacities of facilities for minimal inequality in accessibility, where the measure of accessibility accounts for the match ratio of supply and demand and complex spatial interaction between them. The case study illustrates how the two-step optimization method improves both aspects of spatial accessibility for health care access in rural China.

SMEs, banks and the spatial differentiation of access to finance

OpenAIRE

Zhao, T.; Jones-Evans, D.

2016-01-01

By utilizing the SME Finance Monitor and a unique dataset on the geographical location of all bank branches in 11 UK economic regions, this paper examines the relevance of spatial differentiation on SMEs’ access to bank finance during the period of economic weakness following the 2007 financial crisis. We find evidence suggesting the presence of a regional-specific effect on SMEs’ access to bank finance. Our findings show that greater functional distance between bank headquarters and branches...

The Impact of Varying Statutory Arrangements on Spatial Data Sharing and Access in Regional NRM Bodies

Science.gov (United States)

Paudyal, D. R.; McDougall, K.; Apan, A.

2014-12-01

Spatial information plays an important role in many social, environmental and economic decisions and increasingly acknowledged as a national resource essential for wider societal and environmental benefits. Natural Resource Management is one area where spatial information can be used for improved planning and decision making processes. In Australia, state government organisations are the custodians of spatial information necessary for natural resource management and regional NRM bodies are responsible to regional delivery of NRM activities. The access and sharing of spatial information between government agencies and regional NRM bodies is therefore as an important issue for improving natural resource management outcomes. The aim of this paper is to evaluate the current status of spatial information access, sharing and use with varying statutory arrangements and its impacts on spatial data infrastructure (SDI) development in catchment management sector in Australia. Further, it critically examined whether any trends and significant variations exist due to different institutional arrangements (statutory versus non-statutory) or not. A survey method was used to collect primary data from 56 regional natural resource management (NRM) bodies responsible for catchment management in Australia. Descriptive statistics method was used to show the similarities and differences between statutory and non-statutory arrangements. The key factors which influence sharing and access to spatial information are also explored. The results show the current statutory and administrative arrangements and regional focus for natural resource management is reasonable from a spatial information management perspective and provides an opportunity for building SDI at the catchment scale. However, effective institutional arrangements should align catchment SDI development activities with sub-national and national SDI development activities to address catchment management issues. We found minor

Evaluating Michigan's community hospital access: spatial methods for decision support

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Varnakovida Pariwate

2006-09-01

Full Text Available Abstract Background Community hospital placement is dictated by a diverse set of geographical factors and historical contingency. In the summer of 2004, a multi-organizational committee headed by the State of Michigan's Department of Community Health approached the authors of this paper with questions about how spatial analyses might be employed to develop a revised community hospital approval procedure. Three objectives were set. First, the committee needed visualizations of both the spatial pattern of Michigan's population and its 139 community hospitals. Second, the committee required a clear, defensible assessment methodology to quantify access to existing hospitals statewide, taking into account factors such as distance to nearest hospital and road network density to estimate travel time. Third, the committee wanted to contrast the spatial distribution of existing community hospitals with a theoretical configuration that best met statewide demand. This paper presents our efforts to first describe the distribution of Michigan's current community hospital pattern and its people, and second, develop two models, access-based and demand-based, to identify areas with inadequate access to existing hospitals. Results Using the product from the access-based model and contiguity and population criteria, two areas were identified as being "under-served." The lower area, located north/northeast of Detroit, contained the greater total land area and population of the two areas. The upper area was centered north of Grand Rapids. A demand-based model was applied to evaluate the existing facility arrangement by allocating daily bed demand in each ZIP code to the closest facility. We found 1,887 beds per day were demanded by ZIP centroids more than 16.1 kilometers from the nearest existing hospital. This represented 12.7% of the average statewide daily bed demand. If a 32.3 kilometer radius was employed, unmet demand dropped to 160 beds per day (1

Measuring the impact of efficient household travel decisions on potential travel time savings and accessibility gains

Energy Technology Data Exchange (ETDEWEB)

Recker, W.W.; McNally, M.G. [University of California, Irvine (United States). Institute of Transportation Studies, Department of Civil and Environmental Engineering; Chen, C. [Ming-Chuan University, Taiwan (China). Department of Tourism Industry

2001-07-01

Using the conceptual framework of time-space geography, this paper incorporates both spatio-temporal constraints and household interaction effects into a meaningful measure of the potential of a household to interact with the built environment. Within this context, personal accessibility is described as a measure of the potential ability of individuals within a household not only to reach activity opportunities, but to do so with sufficient time available for participation in those activities, subject to the spatio-temporal constraints imposed by their daily obligations and transportation supply environment. The incorporation of activity-based concepts in the measurement of accessibility as a product of travel time savings not only explicitly acknowledges a temporal dimension in assessing the potential for spatial interaction but also expands the applicability of accessibility consideration to such real-world policy options as the promotion of ride-sharing and trip chaining behaviors. An empirical application of the model system provides an indication of the potential of activity-based modeling approaches to assess the bounds on achievable improvements in accessibility and travel time based on daily household activity patterns. It also provides an assessment of roles for trip chaining and ride-sharing as potentially effective methods to facilitate transportation policy objectives. (author)

Soils - Potential Runoff

Data.gov (United States)

Kansas Data Access and Support Center — This digital spatial data set provides information on the spatial distribution of potential runoff-contributing areas in Kansas. Potential runoff-contributing areas...

What versus where: Investigating how autobiographical memory retrieval differs when accessed with thematic versus spatial information.

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Sheldon, Signy; Chu, Sonja

2017-09-01

Autobiographical memory research has investigated how cueing distinct aspects of a past event can trigger different recollective experiences. This research has stimulated theories about how autobiographical knowledge is accessed and organized. Here, we test the idea that thematic information organizes multiple autobiographical events whereas spatial information organizes individual past episodes by investigating how retrieval guided by these two forms of information differs. We used a novel autobiographical fluency task in which participants accessed multiple memory exemplars to event theme and spatial (location) cues followed by a narrative description task in which they described the memories generated to these cues. Participants recalled significantly more memory exemplars to event theme than to spatial cues; however, spatial cues prompted faster access to past memories. Results from the narrative description task revealed that memories retrieved via event theme cues compared to spatial cues had a higher number of overall details, but those recalled to the spatial cues were recollected with a greater concentration on episodic details than those retrieved via event theme cues. These results provide evidence that thematic information organizes and integrates multiple memories whereas spatial information prompts the retrieval of specific episodic content from a past event.

The NASA Regional Planetary Image Facility (RPIF) Network: A Key Resource for Accessing and Using Planetary Spatial Data

Science.gov (United States)

Hagerty, J. J.

2017-12-01

The role of the NASA Regional Planetary Image Facility (RPIF) Network is evolving as new science-ready spatial data products continue to be created and as key historical planetary data sets are digitized. Specifically, the RPIF Network is poised to serve specialized knowledge and services in a user-friendly manner that removes most barriers to locating, accessing, and exploiting planetary spatial data, thus providing a critical data access role within a spatial data infrastructure. The goal of the Network is to provide support and training to a broad audience of planetary spatial data users. In an effort to meet the planetary science community's evolving needs, we are focusing on the following objectives: Maintain and improve the delivery of historical data accumulated over the past four decades so as not to lose critical, historical information. This is being achieved by systematically digitizing fragile materials, allowing increased access and preserving them at the same time. Help users locate, access, visualize, and exploit planetary science data. Many of the facilities have begun to establish Guest User Facilities that allow researchers to use and/or be trained on GIS equipment and other specialized tools like Socet Set/GXP photogrammetry workstations for generating digital elevation maps. Improve the connection between the Network nodes while also leveraging the unique resources of each node. To achieve this goal, each facility is developing and sharing searchable databases of their collections, including robust metadata in a standards compliant way. Communicate more effectively and regularly with the planetary science community in an effort to make potential users aware of resources and services provided by the Network, while also engaging community members in discussions about community needs. Provide a regional resource for the science community, colleges, universities, museums, media, and the public to access planetary data. Introduce new strategies for

Evaluating the Impact of China’s Rail Network Expansions on Local Accessibility: A Market Potential Approach

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Wenjie Wu

2016-05-01

Full Text Available This paper uses a market potential approach to examine the evolution of the rail transport network of China and its spatial distributional impacts on local accessibility, with a particular focus on high-speed rail improvements. Accessibility is measured by using a “market potential” function that was derived from the general equilibrium model of the economic geography literature, and is empirically calculated based on Geographical Information System (GIS techniques. A key finding, albeit from a highly stylized model, is that rail improvements may help raise territorial polarizing patterns across counties. The results point to the profound implications of railroad network expansion on the accessibility dynamics in periphery regions relative to core regions.

Spatial Release From Masking in Simulated Cochlear Implant Users With and Without Access to Low-Frequency Acoustic Hearing

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Ben Williges

2015-12-01

Full Text Available For normal-hearing listeners, speech intelligibility improves if speech and noise are spatially separated. While this spatial release from masking has already been quantified in normal-hearing listeners in many studies, it is less clear how spatial release from masking changes in cochlear implant listeners with and without access to low-frequency acoustic hearing. Spatial release from masking depends on differences in access to speech cues due to hearing status and hearing device. To investigate the influence of these factors on speech intelligibility, the present study measured speech reception thresholds in spatially separated speech and noise for 10 different listener types. A vocoder was used to simulate cochlear implant processing and low-frequency filtering was used to simulate residual low-frequency hearing. These forms of processing were combined to simulate cochlear implant listening, listening based on low-frequency residual hearing, and combinations thereof. Simulated cochlear implant users with additional low-frequency acoustic hearing showed better speech intelligibility in noise than simulated cochlear implant users without acoustic hearing and had access to more spatial speech cues (e.g., higher binaural squelch. Cochlear implant listener types showed higher spatial release from masking with bilateral access to low-frequency acoustic hearing than without. A binaural speech intelligibility model with normal binaural processing showed overall good agreement with measured speech reception thresholds, spatial release from masking, and spatial speech cues. This indicates that differences in speech cues available to listener types are sufficient to explain the changes of spatial release from masking across these simulated listener types.

Geographical accessibility and spatial coverage modeling of the primary health care network in the Western Province of Rwanda

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Huerta Munoz Ulises

2012-09-01

Full Text Available Abstract Background Primary health care is essential in improving and maintaining the health of populations. It has the potential to accelerate achievement of the Millennium Development Goals and fulfill the “Health for All” doctrine of the Alma-Ata Declaration. Understanding the performance of the health system from a geographic perspective is important for improved health planning and evidence-based policy development. The aims of this study were to measure geographical accessibility, model spatial coverage of the existing primary health facility network, estimate the number of primary health facilities working under capacity and the population underserved in the Western Province of Rwanda. Methods This study uses health facility, population and ancillary data for the Western Province of Rwanda. Three different travel scenarios utilized by the population to attend the nearest primary health facility were defined with a maximum travelling time of 60 minutes: Scenario 1 – walking; Scenario 2 – walking and cycling; and Scenario 3 – walking and public transportation. Considering these scenarios, a raster surface of travel time between primary health facilities and population was developed. To model spatial coverage and estimate the number of primary health facilities working under capacity, the catchment area of each facility was calculated by taking into account population coverage capacity, the population distribution, the terrain topography and the travelling modes through the different land categories. Results Scenario 2 (walking and cycling has the highest degree of geographical accessibility followed by Scenario 3 (walking and public transportation. The lowest level of accessibility can be observed in Scenario 1 (walking. The total population covered differs depending on the type of travel scenario. The existing primary health facility network covers only 26.6% of the population in Scenario 1. In Scenario 2, the use of a bicycle

Localization in a one-dimensional spatially correlated random potential

International Nuclear Information System (INIS)

Kasner, M.; Weller, W.

1986-01-01

The motion of an electron in a random one-dimensional spatially correlated potential is investigated. The spatial correlation is generated by a Markov chain. It is shown that the influence of the spatial correlation can be described by means of oscillating vertices usually neglected in the Berezinskii diagram technique. Correlation mainly leads to an increase of the localization length in comparison with an uncorrelated potential. However, there is a region of the parameter, where the localization decreases. (author)

Increasing Wage Gap, Spatial Structure and Market Access: Evidence from Swedish Micro Data

OpenAIRE

Nabavi, Pardis

2015-01-01

The new economic geography predicts that the wage gap will increase with accessibility to markets but does not consider the impact of spatial proximity. In contrast, urban economic theory explains wage differences by density without accounting for accessibility. Using a rich Swedish micro-panel, we empirically examine the two rival theories for males and females separately, controlling for individual, firm and regional characteristics. The regression results indicate that wage dispersion is c...

ViSA: a neurodynamic model for visuo-spatial working memory, attentional blink, and conscious access.

Science.gov (United States)

Simione, Luca; Raffone, Antonino; Wolters, Gezinus; Salmas, Paola; Nakatani, Chie; Belardinelli, Marta Olivetti; van Leeuwen, Cees

2012-10-01

Two separate lines of study have clarified the role of selectivity in conscious access to visual information. Both involve presenting multiple targets and distracters: one simultaneously in a spatially distributed fashion, the other sequentially at a single location. To understand their findings in a unified framework, we propose a neurodynamic model for Visual Selection and Awareness (ViSA). ViSA supports the view that neural representations for conscious access and visuo-spatial working memory are globally distributed and are based on recurrent interactions between perceptual and access control processors. Its flexible global workspace mechanisms enable a unitary account of a broad range of effects: It accounts for the limited storage capacity of visuo-spatial working memory, attentional cueing, and efficient selection with multi-object displays, as well as for the attentional blink and associated sparing and masking effects. In particular, the speed of consolidation for storage in visuo-spatial working memory in ViSA is not fixed but depends adaptively on the input and recurrent signaling. Slowing down of consolidation due to weak bottom-up and recurrent input as a result of brief presentation and masking leads to the attentional blink. Thus, ViSA goes beyond earlier 2-stage and neuronal global workspace accounts of conscious processing limitations. PsycINFO Database Record (c) 2012 APA, all rights reserved.

Spatial Accessibility of Primary Care in England: A Cross-Sectional Study Using a Floating Catchment Area Method.

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Bauer, Jan; Müller, Ruth; Brüggmann, Dörthe; Groneberg, David A

2017-07-07

To analyze the general practitioners (GPs) with regard to the degree of urbanization, social deprivation, general health, and disability. Small area population data and GP practice data in England. We used a floating catchment area method to measure spatial GP accessibility with regard to the degree of urbanization, social deprivation, general health, and disability. Data were collected from the Office for National Statistics and the general practice census and analyzed using a geographic information system. In all, 25.8 percent of the population in England lived in areas with a significant low GP accessibility (mean z-score: -4.2); 27.6 percent lived in areas with a significant high GP accessibility (mean z-score: 7.7); 97.8 percent of high GP accessibility areas represented urban areas, and 31.1 percent of low GP accessibility areas represented rural areas (correlation of accessibility and urbanity: r = 0.59; psocial deprivation was present (r = -0.19; paccessibility throughout England. However, socially deprived areas did not have poorer spatial access to GPs. © Health Research and Educational Trust.

Exploring the relationship between food access and foodborne illness by using spatial analysis.

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Newbold, Bruce; Watson, Susannah; Mackay, Kevin; Isaacs, Sandy

2013-09-01

There is some evidence that neighborhood deprivation increases residents' risk of foodborne illnesses. Because urban areas with the least available access to adequate amounts of nutritious or affordable food options (or "food deserts") also tend to be the most deprived areas within a city, it is hypothesized that food access and foodborne illness risk are linked. However, the complexity of tracking numbers and sources of gastrointestinal (GI) illnesses often leads researchers to speculate about reasons for disproportionate rates of pathogen outbreaks among demographic groups. This study explores the suitability of existing data to examine associations between food deserts and the spatial distribution of GI illnesses in Hamilton, Ontario, Canada. A spatial analysis by using GIS software methodology was used to identify and map food retail outlets and accessibility, as well as GI illness outbreaks and sales of antidiarrhea, antinausea, and rehydration products (used as a proxy for GI cases) within the city, based on available data. Statistical analysis of the maps shows no statistical relationship between location, access to food outlets, and rates of GI illness. The analysis points to shortfalls and gaps in the existing data, which leaves us unable to draw conclusions either supporting or refuting our hypothesis. This article includes recommendations to improve the current system of illness reporting and to continue to refine the definition and process of mapping food access issues. A more comprehensive set of data would enable municipalities to more easily identify groups most at risk, depending on exposures and the type of pathogen, and reduce the occurrence of foodborne disease.

Measuring potential access to food stores and food-service places in rural areas in the U.S.

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Sharkey, Joseph R

2009-04-01

Geographic access to healthy food resources remains a major focus of research that examines the contribution of the built environment to healthful eating. Methods used to define and measure spatial accessibility can significantly affect the results. Considering the implications for marketing, policy, and programs, adequate measurement of the food environment is important. Little of the published work on food access has focused on rural areas, where the burden of nutrition-related disease is greater. This article seeks to expand our understanding of the challenges to measurement of potential spatial access to food resources in rural areas in the U.S. Key challenges to the accurate measurement of the food environment in rural areas include: (1) defining the rural food environment while recognizing that market factors may be changing; (2) describing characteristics that may differentiate similar types of food stores and food-service places; and (3) determining location coordinates for food stores and food-service places. In order to enhance measurements in rural areas, "ground-truthed" methodology, which includes on-site observation and collection of GPS data, should become the standard for rural areas. Measurement must also recognize the emergence of new and changing store formats. Efforts should be made to determine accessibility, in terms of both proximity to a single location and variety of multiple locations within a specified buffer, from origins other than the home, and consider multipurpose trips and trip chaining. The measurement of food access will be critical for community-based approaches to meet dietary needs. Researchers must be willing to take the steps necessary for rigorous measurement of a dynamic food environment.

A cross-sectional ecological study of spatial scale and geographic inequality in access to drinking-water and sanitation

OpenAIRE

Yu, Weiyu; Bain, Robert ES; Mansour, Shawky; Wright, Jim A

2014-01-01

IntroductionMeasuring inequality in access to safe drinking-water and sanitation is proposed as a component of international monitoring following the expiry of the Millennium Development Goals. This study aims to evaluate the utility of census data in measuring geographic inequality in access to drinking-water and sanitation.MethodsSpatially referenced census data were acquired for Colombia, South Africa, Egypt, and Uganda, whilst non-spatially referenced census data were acquired for Kenya. ...

Spatial Impact of the Road Infrastructure Development in Romania. An Accessibility Approach

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TITUS MAN

2015-06-01

Full Text Available This paper compares the spatial structure of accessibility in Romania before and after the implementation of some major national and/or European road infrastructure projects. This study suggests a new index for accessibility measurement by combining gravity-based models with Place Rank and adapting it to the Romanian system of settlements. Based on the GIS estimation of travel time, this index evaluates not only the geographical position of a specific community relative to the road network, but also the level of accessibility of rural and urban communities to the social services located in central places. The GIS-based maps indicate the existing disparities (between well-connected and isolated regions in terms of accessibility to the central places and the impact of new infrastructure projects on these disparities. The resulting maps can be used as efficient tools for transport planning and development at different scales (international, national, regional and local.

Supermarket access, transport mode and BMI: the potential for urban design and planning policy across socio-economic areas.

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Murphy, Maureen; Koohsari, Mohammad Javad; Badland, Hannah; Giles-Corti, Billie

2017-12-01

To investigate dietary intake, BMI and supermarket access at varying geographic scales and transport modes across areas of socio-economic disadvantage, and to evaluate the implementation of an urban planning policy that provides guidance on spatial access to supermarkets. Cross-sectional study used generalised estimating equations to investigate associations between supermarket density and proximity, vegetable and fruit intake and BMI at five geographic scales representing distances people travel to purchase food by varying transport modes. A stratified analysis by area-level disadvantage was conducted to detect optimal distances to supermarkets across socio-economic areas. Spatial distribution of supermarket and transport access was analysed using a geographic information system. Melbourne, Australia. Adults (n 3128) from twelve local government areas (LGA) across Melbourne. Supermarket access was protective of BMI for participants in high disadvantaged areas within 800 m (P=0·040) and 1000 m (P=0·032) road network buffers around the household but not for participants in less disadvantaged areas. In urban growth area LGA, only 26 % of dwellings were within 1 km of a supermarket, far less than 80-90 % of dwellings suggested in the local urban planning policy. Low public transport access compounded disadvantage. Rapid urbanisation is a global health challenge linked to increases in dietary risk factors and BMI. Our findings highlight the importance of identifying the most appropriate geographic scale to inform urban planning policy for optimal health outcomes across socio-economic strata. Urban planning policy implementation in disadvantaged areas within cities has potential for reducing health inequities.

The comparison of spatial accessibility measures between non-obstacle and obstacle oriented based on gravity model

Science.gov (United States)

Han, Zhi-Gang; Cui, Cai-Hui

2009-10-01

Spatial accessibility denotes the ease with which activities may be reached from a given location using a particular transportation system. There are a number of accessibility measures methods and models, such as time of access to city centre, mean travel costs and opportunity accessibility. But these methods or models ignore the existence of obstacles. In fact, there are many kinds of obstacles in the world, such as rivers, railways, etc. The paper reviews the progress of accessibility measures, and introduces the obstacle to the accessibility measures. Meanwhile, through the analysis of A* algorithm, the advantage of A* algorithm that could avoid obstacles is put forward. Based on the above mentioned, the obstacle oriented accessibility measures based on simple gravity model is discussed in details. Finally, a case study is fulfilled by comparison between the obstacle oriented and non-obstacle accessibility measures.

Toward Accessing Spatial Structure from Building Information Models

Science.gov (United States)

Schultz, C.; Bhatt, M.

2011-08-01

Data about building designs and layouts is becoming increasingly more readily available. In the near future, service personal (such as maintenance staff or emergency rescue workers) arriving at a building site will have immediate real-time access to enormous amounts of data relating to structural properties, utilities, materials, temperature, and so on. The critical problem for users is the taxing and error prone task of interpreting such a large body of facts in order to extract salient information. This is necessary for comprehending a situation and deciding on a plan of action, and is a particularly serious issue in time-critical and safety-critical activities such as firefighting. Current unifying building models such as the Industry Foundation Classes (IFC), while being comprehensive, do not directly provide data structures that focus on spatial reasoning and spatial modalities that are required for high-level analytical tasks. The aim of the research presented in this paper is to provide computational tools for higher level querying and reasoning that shift the cognitive burden of dealing with enormous amounts of data away from the user. The user can then spend more energy and time in planning and decision making in order to accomplish the tasks at hand. We present an overview of our framework that provides users with an enhanced model of "built-up space". In order to test our approach using realistic design data (in terms of both scale and the nature of the building models) we describe how our system interfaces with IFC, and we conduct timing experiments to determine the practicality of our approach. We discuss general computational approaches for deriving higher-level spatial modalities by focusing on the example of route graphs. Finally, we present a firefighting scenario with alternative route graphs to motivate the application of our framework.

Interspecific interference competition at the resource patch scale: do large herbivores spatially avoid elephants while accessing water?

Science.gov (United States)

Ferry, Nicolas; Dray, Stéphane; Fritz, Hervé; Valeix, Marion

2016-11-01

Animals may anticipate and try to avoid, at some costs, physical encounters with other competitors. This may ultimately impact their foraging distribution and intake rates. Such cryptic interference competition is difficult to measure in the field, and extremely little is known at the interspecific level. We tested the hypothesis that smaller species avoid larger ones because of potential costs of interference competition and hence expected them to segregate from larger competitors at the scale of a resource patch. We assessed fine-scale spatial segregation patterns between three African herbivore species (zebra Equus quagga, kudu Tragelaphus strepsiceros and giraffe Giraffa camelopardalis) and a megaherbivore, the African elephant Loxodonta africana, at the scale of water resource patches in the semi-arid ecosystem of Hwange National Park, Zimbabwe. Nine waterholes were monitored every two weeks during the dry season of a drought year, and observational scans of the spatial distribution of all herbivores were performed every 15 min. We developed a methodological approach to analyse such fine-scale spatial data. Elephants increasingly used waterholes as the dry season progressed, as did the probability of co-occurrence and agonistic interaction with elephants for the three study species. All three species segregated from elephants at the beginning of the dry season, suggesting a spatial avoidance of elephants and the existence of costs of being close to them. However, contrarily to our expectations, herbivores did not segregate from elephants the rest of the dry season but tended to increasingly aggregate with elephants as the dry season progressed. We discuss these surprising results and the existence of a trade-off between avoidance of interspecific interference competition and other potential factors such as access to quality water, which may have relative associated costs that change with the time of the year. © 2016 The Authors. Journal of Animal Ecology �

Spatial mapping of renewable energy potential

Energy Technology Data Exchange (ETDEWEB)

Ramachandra, T.V. [Centre for Sustainable Technologies, Indian Institute of Science, Bangalore (India); Energy Research Group, CES RNO 215, Centre for Ecological Sciences, Indian Institute of Science, Bangalore 560 012 (India); Shruthi, B.V. [Energy Research Group, CES RNO 215, Centre for Ecological Sciences, Indian Institute of Science, Bangalore 560 012 (India)

2007-09-15

An energy resource that is renewed by nature and whose supply is not affected by the rate of consumption is often termed as renewable energy. The need to search for renewable, alternate and non-polluting sources of energy assumes top priority for self-reliance in the regional energy supply. This demands an estimation of available energy resources spatially to evolve better management strategies for ensuring sustainability of resources. The spatial mapping of availability and demand of energy resources would help in the integrated regional energy planning through an appropriate energy supply-demand matching. This paper discusses the application of Geographical Information System (GIS) to map the renewable energy potential talukwise in Karnataka State, India. Taluk is an administrative division in the federal set-up in India to implement developmental programmes like dissemination of biogas, improved stoves, etc. Hence, this paper focuses talukwise mapping of renewable energy (solar, wind, bioenergy and small hydroenergy) potential for Karnataka using GIS. GIS helps in spatial and temporal analyses of the resources and demand and also aids as Decision Support System while implementing location-specific renewable energy technologies. Regions suitable for tapping solar energy are mapped based on global solar radiation data, which provides a picture of the potential. Coastal taluks in Uttara Kannada have higher global solar radiation during summer (6.31 kWh/m{sup 2}), monsoon (4.16 kWh/m{sup 2}) and winter (5.48 kWh/m{sup 2}). Mapping of regions suitable for tapping wind energy has been done based on wind velocity data, and it shows that Chikkodi taluk, Belgaum district, has higher potential during summer (6.06 m/s), monsoon (8.27 m/s) and winter (5.19 m/s). Mysore district has the maximum number of small hydropower plants with a capacity of 36 MW. Talukwise computation of bioenergy availability from agricultural residue, forest, horticulture, plantation and livestock

Small-Area Estimation of Spatial Access to Care and Its Implications for Policy.

Science.gov (United States)

Gentili, Monica; Isett, Kim; Serban, Nicoleta; Swann, Julie

2015-10-01

Local or small-area estimates to capture emerging trends across large geographic regions are critical in identifying and addressing community-level health interventions. However, they are often unavailable due to lack of analytic capabilities in compiling and integrating extensive datasets and complementing them with the knowledge about variations in state-level health policies. This study introduces a modeling approach for small-area estimation of spatial access to pediatric primary care that is data "rich" and mathematically rigorous, integrating data and health policy in a systematic way. We illustrate the sensitivity of the model to policy decision making across large geographic regions by performing a systematic comparison of the estimates at the census tract and county levels for Georgia and California. Our results show the proposed approach is able to overcome limitations of other existing models by capturing patient and provider preferences and by incorporating possible changes in health policies. The primary finding is systematic underestimation of spatial access, and inaccurate estimates of disparities across population and across geography at the county level with respect to those at the census tract level with implications on where to focus and which type of interventions to consider.

A cross-sectional ecological study of spatial scale and geographic inequality in access to drinking-water and sanitation.

Science.gov (United States)

Yu, Weiyu; Bain, Robert E S; Mansour, Shawky; Wright, Jim A

2014-11-26

Measuring inequality in access to safe drinking-water and sanitation is proposed as a component of international monitoring following the expiry of the Millennium Development Goals. This study aims to evaluate the utility of census data in measuring geographic inequality in access to drinking-water and sanitation. Spatially referenced census data were acquired for Colombia, South Africa, Egypt, and Uganda, whilst non-spatially referenced census data were acquired for Kenya. Four variants of the dissimilarity index were used to estimate geographic inequality in access to both services using large and small area units in each country through a cross-sectional, ecological study. Inequality was greatest for piped water in South Africa in 2001 (based on 53 areas (N) with a median population (MP) of 657,015; D = 0.5599) and lowest for access to an improved water source in Uganda in 2008 (N = 56; MP = 419,399; D = 0.2801). For sanitation, inequality was greatest for those lacking any facility in Kenya in 2009 (N = 158; MP = 216,992; D = 0.6981), and lowest for access to an improved facility in Uganda in 2002 (N = 56; MP = 341,954; D = 0.3403). Although dissimilarity index values were greater for smaller areal units, when study countries were ranked in terms of inequality, these ranks remained unaffected by the choice of large or small areal units. International comparability was limited due to definitional and temporal differences between censuses. This five-country study suggests that patterns of inequality for broad regional units do often reflect inequality in service access at a more local scale. This implies household surveys designed to estimate province-level service coverage can provide valuable insights into geographic inequality at lower levels. In comparison with household surveys, censuses facilitate inequality assessment at different spatial scales, but pose challenges in harmonising water and sanitation typologies across countries.

Modeling Urban Spatial Growth in Mountainous Regions of Western China

Directory of Open Access Journals (Sweden)

Guoping Huang

2017-08-01

Full Text Available The scale and speed of urbanization in the mountainous regions of western China have received little attention from researchers. These cities are facing rapid population growth and severe environmental degradation. This study analyzed historical urban growth trends in this mountainous region to better understand the interaction between the spatial growth pattern and the mountainous topography. Three major factors—slope, accessibility, and land use type—were studied in light of their relationships with urban spatial growth. With the analysis of historical data as the basis, a conceptual urban spatial growth model was devised. In this model, slope, accessibility, and land use type together create resistance to urban growth, while accessibility controls the sequence of urban development. The model was tested and evaluated using historical data. It serves as a potential tool for planners to envision and assess future urban growth scenarios and their potential environmental impacts to make informed decisions.

Spatial data analysis and integration for regional-scale geothermal potential mapping, West Java, Indonesia

Energy Technology Data Exchange (ETDEWEB)

Carranza, Emmanuel John M.; Barritt, Sally D. [Department of Earth Systems Analysis, International Institute for Geo-information Science and Earth Observation (ITC), Enschede (Netherlands); Wibowo, Hendro; Sumintadireja, Prihadi [Laboratory of Volcanology and Geothermal, Geology Department, Institute of Technology Bandung (ITB), Bandung (Indonesia)

2008-06-15

Conceptual modeling and predictive mapping of potential for geothermal resources at the regional-scale in West Java are supported by analysis of the spatial distribution of geothermal prospects and thermal springs, and their spatial associations with geologic features derived from publicly available regional-scale spatial data sets. Fry analysis shows that geothermal occurrences have regional-scale spatial distributions that are related to Quaternary volcanic centers and shallow earthquake epicenters. Spatial frequency distribution analysis shows that geothermal occurrences have strong positive spatial associations with Quaternary volcanic centers, Quaternary volcanic rocks, quasi-gravity lows, and NE-, NNW-, WNW-trending faults. These geological features, with their strong positive spatial associations with geothermal occurrences, constitute spatial recognition criteria of regional-scale geothermal potential in a study area. Application of data-driven evidential belief functions in GIS-based predictive mapping of regional-scale geothermal potential resulted in delineation of high potential zones occupying 25% of West Java, which is a substantial reduction of the search area for further exploration of geothermal resources. The predicted high potential zones delineate about 53-58% of the training geothermal areas and 94% of the validated geothermal occurrences. The results of this study demonstrate the value of regional-scale geothermal potential mapping in: (a) data-poor situations, such as West Java, and (b) regions with geotectonic environments similar to the study area. (author)

Institutions in transitioning peri-urban communities: spatial differences in groundwater access

Science.gov (United States)

Gomes, Sharlene L.; Hermans, Leon M.

2016-05-01

Urbanization creates challenges for water management in an evolving socio-economic context. This is particularly relevant in transitioning peri-urban areas like Khulna, Bangladesh where competing demands have put pressure on local groundwater resources. Users are unable to sufficiently meet their needs through existing institutions. These institutions provide the rules for service provision and act as guidelines for actors to resolve their water related issues. However, the evolving peri-urban context can produce fragmented institutional arrangements. For example in Khulna, water supply is based on urban and rural boundaries that has created water access issues for peri-urban communities. This has motivated local actors to manage their groundwater needs in various ways. General institutional theories are well developed in literature, yet little is known about institutions in transitioning peri-urban areas. Institutions that fail to adapt to changing dynamics run the risk of becoming obsolete or counter-productive, hence the need for investigating institutional change mechanisms in this context. This paper examines peri-urban case studies from Khulna using the Institutional Analysis and Development framework to demonstrate how institutions have contributed to spatial differences in groundwater access with local actors investing in formal and informal institutional change as a means of accessing groundwater.

Spatial modeling of potential woody biomass flow

Science.gov (United States)

Woodam Chung; Nathaniel Anderson

2012-01-01

The flow of woody biomass to end users is determined by economic factors, especially the amount available across a landscape and delivery costs of bioenergy facilities. The objective of this study develop methodology to quantify landscape-level stocks and potential biomass flows using the currently available spatial database road network analysis tool. We applied this...

Assessing spatial access to public and private hospitals in Sichuan, China: The influence of the private sector on the healthcare geography in China.

Science.gov (United States)

Pan, Jay; Zhao, Hanqing; Wang, Xiuli; Shi, Xun

2016-12-01

In 2009, the Chinese government launched a new round of healthcare reform, which encourages development of private hospitals. Meanwhile, many public hospitals in China also became increasingly profit-oriented. These trends have led to concerns about social justice and regional disparity. However, there is a lack of empirical scientific analysis to support the debate. We started to fill this gap by conducting a regional-level analysis of spatial variation in spatial access to hospitals in the Sichuan Province. Such variation is an important indication of (in) equity in healthcare resource allocation. Using data of 2012, we intended to provide a snapshot of the situation that was a few years later since the new policies had set out. We employed two methods to quantify the spatial access: the nearest-neighbor method and the enhanced two-step floating catchment area (E2SFCA) method. We recognized two sub-regions of Sichuan: the rural West Sichuan and the well-developed East Sichuan. We classified the hospitals using both ownership and level. We applied the analysis to the resulting groups of hospitals and their combinations in the two sub-regions. The two sub-regions have a high contrast in the spatial access to hospitals, in terms of both quantity and spatial pattern. Public hospitals still dominated the service in the province, especially in the West Sichuan, which had been solely relying on public hospitals. Private hospitals only occurred in the East Sichuan, and at the primary level, they had surpassed public hospitals in terms of spatial accessibility. However, the governmental health expenditures seemed to be disconnected with the actual situation of the spatial access to hospitals. The government should continue carrying on its responsibility in allocating healthcare resources, be cautious about marketizing public hospitals, and encourage private hospitals to expand into rural areas. Methodologically, the results from the two methods are concurring but not

Potential of OFDM for next generation optical access

Science.gov (United States)

Fritzsche, Daniel; Weis, Erik; Breuer, Dirk

2011-01-01

This paper shows the requirements for next generation optical access (NGOA) networks and analyzes the potential of OFDM (orthogonal frequency division multiplexing) for the use in such network scenarios. First, we show the motivation for NGOA systems based on the future requirements on FTTH access systems and list the advantages of OFDM in such scenarios. In the next part, the basics of OFDM and different methods to generate and detect optical OFDM signals are explained and analyzed. At the transmitter side the options include intensity modulation and the more advanced field modulation of the optical OFDM signal. At the receiver there is the choice between direct detection and coherent detection. As the result of this discussion we show our vision of the future use of OFDM in optical access networks.

The potential use of mobile technology: enhancing accessibility and ...

African Journals Online (AJOL)

The potential use of mobile technology: enhancing accessibility and communication in a blended ... South African Journal of Education ... Recommendations, limitations of the present study, and suggestions for future research were made.

Unequal access to higher education in the Czech Republic: the role of spatial distribution of universities

Czech Academy of Sciences Publication Activity Database

Franta, Michal; Guzi, Martin

-, č. 350 (2008), s. 1-56 ISSN 1211-3298 R&D Projects: GA MŠk LC542 Institutional research plan: CEZ:AV0Z70850503 Keywords : access to tertiary education * human capital * spatial distribution Subject RIV: AH - Economics http://www.cerge-ei.cz/pdf/wp/Wp350.pdf

Filter multiplexing by use of spatial Code Division Multiple Access approach.

Science.gov (United States)

Solomon, Jonathan; Zalevsky, Zeev; Mendlovic, David; Monreal, Javier Garcia

2003-02-10

The increasing popularity of optical communication has also brought a demand for a broader bandwidth. The trend, naturally, was to implement methods from traditional electronic communication. One of the most effective traditional methods is Code Division Multiple Access. In this research, we suggest the use of this approach for spatial coding applied to images. The approach is to multiplex several filters into one plane while keeping their mutual orthogonality. It is shown that if the filters are limited by their bandwidth, the output of all the filters can be sampled in the original image resolution and fully recovered through an all-optical setup. The theoretical analysis of such a setup is verified in an experimental demonstration.

Spatial distribution of potential and positive Aedes aegypti breeding sites

Directory of Open Access Journals (Sweden)

Daniel Elías Cuartas

2017-03-01

Conclusions: The spatial relationship between positive and potential A. aegypti breeding sites both indoors and outdoors is dynamic and highly sensitive to the characteristics of each territory. Knowing how positive and potential breeding sites are distributed contributes to the prioritization of resources and actions in vector control programs.

High-Resolution Spatial Distribution and Estimation of Access to Improved Sanitation in Kenya.

Science.gov (United States)

Jia, Peng; Anderson, John D; Leitner, Michael; Rheingans, Richard

2016-01-01

Access to sanitation facilities is imperative in reducing the risk of multiple adverse health outcomes. A distinct disparity in sanitation exists among different wealth levels in many low-income countries, which may hinder the progress across each of the Millennium Development Goals. The surveyed households in 397 clusters from 2008-2009 Kenya Demographic and Health Surveys were divided into five wealth quintiles based on their national asset scores. A series of spatial analysis methods including excess risk, local spatial autocorrelation, and spatial interpolation were applied to observe disparities in coverage of improved sanitation among different wealth categories. The total number of the population with improved sanitation was estimated by interpolating, time-adjusting, and multiplying the surveyed coverage rates by high-resolution population grids. A comparison was then made with the annual estimates from United Nations Population Division and World Health Organization /United Nations Children's Fund Joint Monitoring Program for Water Supply and Sanitation. The Empirical Bayesian Kriging interpolation produced minimal root mean squared error for all clusters and five quintiles while predicting the raw and spatial coverage rates of improved sanitation. The coverage in southern regions was generally higher than in the north and east, and the coverage in the south decreased from Nairobi in all directions, while Nyanza and North Eastern Province had relatively poor coverage. The general clustering trend of high and low sanitation improvement among surveyed clusters was confirmed after spatial smoothing. There exists an apparent disparity in sanitation among different wealth categories across Kenya and spatially smoothed coverage rates resulted in a closer estimation of the available statistics than raw coverage rates. Future intervention activities need to be tailored for both different wealth categories and nationally where there are areas of greater needs when

High-Resolution Spatial Distribution and Estimation of Access to Improved Sanitation in Kenya.

Directory of Open Access Journals (Sweden)

Peng Jia

Full Text Available Access to sanitation facilities is imperative in reducing the risk of multiple adverse health outcomes. A distinct disparity in sanitation exists among different wealth levels in many low-income countries, which may hinder the progress across each of the Millennium Development Goals.The surveyed households in 397 clusters from 2008-2009 Kenya Demographic and Health Surveys were divided into five wealth quintiles based on their national asset scores. A series of spatial analysis methods including excess risk, local spatial autocorrelation, and spatial interpolation were applied to observe disparities in coverage of improved sanitation among different wealth categories. The total number of the population with improved sanitation was estimated by interpolating, time-adjusting, and multiplying the surveyed coverage rates by high-resolution population grids. A comparison was then made with the annual estimates from United Nations Population Division and World Health Organization /United Nations Children's Fund Joint Monitoring Program for Water Supply and Sanitation.The Empirical Bayesian Kriging interpolation produced minimal root mean squared error for all clusters and five quintiles while predicting the raw and spatial coverage rates of improved sanitation. The coverage in southern regions was generally higher than in the north and east, and the coverage in the south decreased from Nairobi in all directions, while Nyanza and North Eastern Province had relatively poor coverage. The general clustering trend of high and low sanitation improvement among surveyed clusters was confirmed after spatial smoothing.There exists an apparent disparity in sanitation among different wealth categories across Kenya and spatially smoothed coverage rates resulted in a closer estimation of the available statistics than raw coverage rates. Future intervention activities need to be tailored for both different wealth categories and nationally where there are areas of

When roads appear jaguars decline: Increased access to an Amazonian wilderness area reduces potential for jaguar conservation.

Science.gov (United States)

Espinosa, Santiago; Celis, Gerardo; Branch, Lyn C

2018-01-01

Roads are a main threat to biodiversity conservation in the Amazon, in part, because roads increase access for hunters. We examine how increased landscape access by hunters may lead to cascading effects that influence the prey community and abundance of the jaguar (Panthera onca), the top Amazonian terrestrial predator. Understanding such ecological effects originating from anthropogenic actions is essential for conservation and management of wildlife populations in areas undergoing infrastructure development. Our study was conducted in Yasuní Biosphere Reserve, the protected area with highest potential for jaguar conservation in Ecuador, and an area both threatened by road development and inhabited by indigenous groups dependent upon bushmeat. We surveyed prey and jaguar abundance with camera traps in four sites that differed in accessibility to hunters and used site occupancy and spatially explicit capture-recapture analyses to evaluate prey occurrence and estimate jaguar density, respectively. Higher landscape accessibility to hunters was linked with lower occurrence and biomass of game, particularly white-lipped peccary (Tayassu pecari) and collared peccary (Pecari tajacu), the primary game for hunters and prey for jaguars. Jaguar density was up to 18 times higher in the most remote site compared to the most accessible site. Our results provide a strong case for the need to: 1) consider conservation of large carnivores and other wildlife in policies about road construction in protected areas, 2) coordinate conservation initiatives with local governments so that development activities do not conflict with conservation objectives, and 3) promote development of community-based strategies for wildlife management that account for the needs of large carnivores.

MExLab Planetary Geoportal: 3D-access to planetary images and results of spatial data analysis

Science.gov (United States)

Karachevtseva, I.; Garov, A.

2015-10-01

MExLab Planetary Geoportal was developed as Geodesy and Cartography Node which provide access to results of study of celestial bodies such as DEM and orthoimages, as well as basemaps, crater catalogues and derivative products: slope, roughness, crater density (http://cartsrv.mexlab.ru/geoportal). The main feature of designed Geoportal is the ability of spatial queries and access to the contents selecting from the list of available data set (Phobos, Mercury, Moon, including Lunokhod's archive data). Prior version of Geoportal has been developed using Flash technology. Now we are developing new version which will use 3D-API (OpenGL, WebGL) based on shaders not only for standard 3D-functionality, but for 2D-mapping as well. Users can obtain quantitative and qualitative characteristics of the objects in graphical, tabular and 3D-forms. It will bring the advantages of unification of code and speed of processing and provide a number of functional advantages based on GIS-tools such as: - possibility of dynamic raster transform for needed map projection; - effective implementation of the co-registration of planetary images by combining spatial data geometries; - presentation in 3D-form different types of data, including planetary atmospheric measurements, subsurface radar data, ect. The system will be created with a new software architecture, which has a potential for development and flexibility in reconfiguration based on cross platform solution: - an application for the three types of platforms: desktop (Windows, Linux, OSX), web platform (any HTML5 browser), and mobile application (Android, iOS); - a single codebase shared between platforms (using cross compilation for Web); - a new telecommunication solution to connect between modules and external system like PROVIDE WebGIS (http://www.provide-space.eu/progis/). The research leading to these result was partly supported by the European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement n

Spatial modelling of landscape aesthetic potential in urban-rural fringes.

Science.gov (United States)

Sahraoui, Yohan; Clauzel, Céline; Foltête, Jean-Christophe

2016-10-01

The aesthetic potential of landscape has to be modelled to provide tools for land-use planning. This involves identifying landscape attributes and revealing individuals' landscape preferences. Landscape aesthetic judgments of individuals (n = 1420) were studied by means of a photo-based survey. A set of landscape visibility metrics was created to measure landscape composition and configuration in each photograph using spatial data. These metrics were used as explanatory variables in multiple linear regressions to explain aesthetic judgments. We demonstrate that landscape aesthetic judgments may be synthesized in three consensus groups. The statistical results obtained show that landscape visibility metrics have good explanatory power. Ultimately, we propose a spatial modelling of landscape aesthetic potential based on these results combined with systematic computation of visibility metrics. Copyright © 2016 Elsevier Ltd. All rights reserved.

Spatial analysis of cattle and shoat population in Ethiopia: growth trend, distribution and market access.

Science.gov (United States)

Leta, Samson; Mesele, Frehiwot

2014-01-01

The livestock subsector has an enormous contribution to Ethiopia's national economy and livelihoods of many Ethiopians. The subsector contributes about 16.5% of the national Gross Domestic Product (GDP) and 35.6% of the agricultural GDP. It also contributes 15% of export earnings and 30% of agricultural employment. The livestock subsector currently support and sustain livelihoods for 80% of all rural population. The GDP of livestock related activities valued at 59 billion birr. Ethiopian livestock population trends, distribution and marketing vary considerably across space and time due to a variety of reasons. This study was aimed to assess cattle and shoat population growth trend, distribution and their access to market. Regression analysis was used to assess the cattle and shoat population growth trend and Geographic Information Systems (GIS) techniques were used to determine the spatial distribution of cattle and shoats, and their relative access to market. The data sets used are agricultural census (2001/02) and annual CSA agricultural sample survey (1995/96 to 2012/13). In the past eighteen years, the livestock population namely cattle, sheep and goat grew from 54.5 million to over 103.5 million with average annual increment of 3.4 million. The current average national cattle, sheep and goat population per km(2) are estimated to be 71, 33 and 29 respectively (excluding Addis Ababa, Afar and Somali regions). From the total livestock population the country owns about 46% cattle, 43% sheep and 40% goats are reared within 10 km radius from major livestock market centres and all-weather roads. On the other hand, three fourth of the country's land mass which comprises 15% of the cattle, 20% of the sheep and 21% of goat population is not accessible to market (greater than 30 km from major livestock market centres). It is found that the central highland regions account for the largest share of livestock population and also more accessible to market. Defining the

Potential and flux field landscape theory. I. Global stability and dynamics of spatially dependent non-equilibrium systems.

Science.gov (United States)

Wu, Wei; Wang, Jin

2013-09-28

We established a potential and flux field landscape theory to quantify the global stability and dynamics of general spatially dependent non-equilibrium deterministic and stochastic systems. We extended our potential and flux landscape theory for spatially independent non-equilibrium stochastic systems described by Fokker-Planck equations to spatially dependent stochastic systems governed by general functional Fokker-Planck equations as well as functional Kramers-Moyal equations derived from master equations. Our general theory is applied to reaction-diffusion systems. For equilibrium spatially dependent systems with detailed balance, the potential field landscape alone, defined in terms of the steady state probability distribution functional, determines the global stability and dynamics of the system. The global stability of the system is closely related to the topography of the potential field landscape in terms of the basins of attraction and barrier heights in the field configuration state space. The effective driving force of the system is generated by the functional gradient of the potential field alone. For non-equilibrium spatially dependent systems, the curl probability flux field is indispensable in breaking detailed balance and creating non-equilibrium condition for the system. A complete characterization of the non-equilibrium dynamics of the spatially dependent system requires both the potential field and the curl probability flux field. While the non-equilibrium potential field landscape attracts the system down along the functional gradient similar to an electron moving in an electric field, the non-equilibrium flux field drives the system in a curly way similar to an electron moving in a magnetic field. In the small fluctuation limit, the intrinsic potential field as the small fluctuation limit of the potential field for spatially dependent non-equilibrium systems, which is closely related to the steady state probability distribution functional, is

Spatial-phase code-division multiple-access system with multiplexed Fourier holography switching for reconfigurable optical interconnection

Science.gov (United States)

Takasago, Kazuya; Takekawa, Makoto; Shirakawa, Atsushi; Kannari, Fumihiko

2000-05-01

A new, to our knowledge, space-variant optical interconnection system based on a spatial-phase code-division multiple-access technique with multiplexed Fourier holography is described. In this technique a signal beam is spread over wide spatial frequencies by an M -sequence pseudorandom phase code. At a receiver side a selected signal beam is properly decoded, and at the same time its spatial pattern is shaped with a Fourier hologram, which is recorded by light that is encoded with the same M -sequence phase mask as the desired signal beam and by light whose spatial beam pattern is shaped to a signal routing pattern. Using the multiplexed holography, we can simultaneously route multisignal flows into individually specified receiver elements. The routing pattern can also be varied by means of switching the encoding phase code or replacing the hologram. We demonstrated a proof-of-principle experiment with a doubly multiplexed hologram that enables simultaneous routing of two signal beams. Using a numerical model, we showed that the proposed scheme can manage more than 250 routing patterns for one signal flow with one multiplexed hologram at a signal-to-noise ratio of 5.

Spatial adaptation of the cortical visual evoked potential of the cat.

Science.gov (United States)

Bonds, A B

1984-06-01

Adaptation that is spatially specific for the adapting pattern has been seen psychophysically in humans. This is indirect evidence for independent analyzers (putatively single units) that are specific for orientation and spatial frequency in the human visual system, but it is unclear how global adaptation characteristics may be related to single unit performance. Spatially specific adaptation was sought in the cat visual evoked potential (VEP), with a view towards relating this phenomenon with what we know of cat single units. Adaptation to sine-wave gratings results in a temporary loss of cat VEP amplitude, with induction and recovery similar to that seen in human psychophysical experiments. The amplitude loss was specific for both the spatial frequency and orientation of the adapting pattern. The bandwidth of adaptation was not unlike the average selectivity of a population of cat single units.

On the ideal low-frequency spatial filtration of the electrical potential at infinity

International Nuclear Information System (INIS)

Gluskin, Emanuel

2005-01-01

It is proved that for any physical system with localized voltage input the potential at infinity is the arithmetic average of the given input potentials. This is relevant to the topic of grounding of a system. In terms of spatial filtering, which is becoming a more and more important concept in modern system theory, we have here ideal filtration of the dc component of the (spatial) input voltage 'signal' (i.e., the set of the given input potentials) at 'infinity' considered as the 'filter's output'. A symmetry argument, helpful in numerical simulations, is considered. Some basic system-theory terms, important for the physical side, are carefully defined

Effective spatial database support for acquiring spatial information from remote sensing images

Science.gov (United States)

Jin, Peiquan; Wan, Shouhong; Yue, Lihua

2009-12-01

In this paper, a new approach to maintain spatial information acquiring from remote-sensing images is presented, which is based on Object-Relational DBMS. According to this approach, the detected and recognized results of targets are stored and able to be further accessed in an ORDBMS-based spatial database system, and users can access the spatial information using the standard SQL interface. This approach is different from the traditional ArcSDE-based method, because the spatial information management module is totally integrated into the DBMS and becomes one of the core modules in the DBMS. We focus on three issues, namely the general framework for the ORDBMS-based spatial database system, the definitions of the add-in spatial data types and operators, and the process to develop a spatial Datablade on Informix. The results show that the ORDBMS-based spatial database support for image-based target detecting and recognition is easy and practical to be implemented.

The emergence of spatial cyberinfrastructure.

Science.gov (United States)

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.

GIS for the Valorization of Hardly Accessible Alpine Areas with Complex Potentials for Tourism, with a View to Their Inclusion in Tourist Routes. Development of the Valleys of Lotru and Olteţ

Directory of Open Access Journals (Sweden)

OANA POPESCU

2008-01-01

Full Text Available VALOT originates in the experience of European countries from the Alpine Space that succeeded to establish three top priorities for hardly accessible mountain areas based on communitarian programs (Natura 2000, Interreg IIIB – AlpNa Tour, VIADVENTURE, RegioMarket, etc.: competitiveness and attractiveness of the Alpine Space, accessibility and connectivity between high altitude settlements, environmental protection and prevention of natural hazards and disasters (snow falls, land slides, etc.. Starting from the project of Law on Approving the National Spatial Plan – Section VI – Tourism, the project aims at evaluating the current resources of hardly accessible mountain areas with complex potentials for tourism according to the experience of the European Union. GIS analysis will underline national/regional disparities of these areas, leading to conclusions on their typology and intervention proposals. The second part will focus on a case study of a hardly accessible area with a high landscape value and still un-valorized potentials for tourism. The existing situation of the area between the Lotru and Parâng mountains, consisting of the territories of four communes and a city, belonging to the counties of Vâlcea and Gorj, will be analyzed. Based on a spatial development scenario using selected statistical and geographic indicators, intervention priorities will be analyzed with the SPATIAL ANALYST, as well as funding possibilities for the creation of a cluster of mountain resorts (Rânca, Vidra, Voineasa in order to valorize the recreational and balneary patrimony of the area, observing principles and objectives of sustainable development in mountain areas. The project will create a methodology for diagnosing problems and dysfunctions of such areas, development possibilities based on the experience of the pilot study, proposals for improving the institutional framework for implementing, monitoring and evaluating the results and (last but not

Spatial and Semantic Processing between Audition and Vision: An Event-Related Potential Study

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Xiaoxi Chen

2011-10-01

Full Text Available Using a crossmodal priming paradigm, this study investigated how the brain bound the spatial and semantic features in multisensory processing. The visual stimuli (pictures of animals were presented after the auditory stimuli (sounds of animals, and the stimuli from different modalities may match spatially (or semantically or not. Participants were required to detect the head orientation of the visual target (an oddball paradigm. The event-related potentials (ERPs to the visual stimuli was enhanced by spatial attention (150–170 ms irrespectively of semantic information. The early crossmodal attention effect for the visual stimuli was more negative in the spatial-congruent condition than in the spatial-incongruent condition. By contrast, the later effects of spatial ERPs were significant only for the semantic- congruent condition (250–300 ms. These findings indicated that spatial attention modulated early visual processing, and semantic and spatial features were simultaneously used to orient attention and modulate later processing stages.

Daily Access to Sucrose Impairs Aspects of Spatial Memory Tasks Reliant on Pattern Separation and Neural Proliferation in Rats

Science.gov (United States)

Reichelt, Amy C.; Morris, Margaret J.; Westbrook, Reginald Frederick

2016-01-01

High sugar diets reduce hippocampal neurogenesis, which is required for minimizing interference between memories, a process that involves "pattern separation." We provided rats with 2 h daily access to a sucrose solution for 28 d and assessed their performance on a spatial memory task. Sucrose consuming rats discriminated between objects…

Revealed access to haemodialysis facilities in northeastern Iran: Factors that matter in rural and urban areas.

Science.gov (United States)

Kiani, Behzad; Bagheri, Nasser; Tara, Ahmad; Hoseini, Benyamin; Tabesh, Hamed; Tara, Mahmood

2017-11-07

Poor access to haemodialysis facilities is associated with high mortality and morbidity rates. This study investigated factors affecting revealed access to the haemodialysis facilities considering patients living in rural and urban areas without any haemodialysis facility (Group A) and those living urban areas with haemodialysis facilities (Group B). This study is based on selfreported Actual Access Time (AAT) to referred haemodialysis facilities and other information regarding travel to haemodialysis facilities from patients. All significant variables on univariate analysis were entered into a univariate general linear model in order to identify factors associated with AAT. Both spatial (driving time and distance) and non-spatial factors (sex, income level, caregivers, transportation mode, education level, ethnicity and personal vehicle ownership) influenced the revealed access identified in Group A. The non-spatial factors for Group B patients were the same as for Group A, but no spatial factor was identified in Group B. It was found that accessibility is strongly underestimated when driving time is chosen as accessibility measure to haemodialysis facilities. Analysis of revealed access determinants provides policymakers with an appropriate decision base for making appropriate decisions and finding solutions to decrease the access time for patients under haemodialysis therapy. Driving time alone is not a good proxy for measuring access to haemodialysis facilities as there are many other potential obstacles, such as women's special travel problems, poor other transportation possibilities, ethnicity disparities, low education levels, low caregiver status and low-income.

Spatial and frequency domain ring source models for the single muscle fiber action potential

DEFF Research Database (Denmark)

Henneberg, Kaj-åge; R., Plonsey

1994-01-01

In the paper, single-fibre models for the extracellular action potential are developed that will allow the potential to the evaluated at an arbitrary field point in the extracellular space. Fourier-domain models are restricted in that they evaluate potentials at equidistant points along a line...... parallel to the fibre axis. Consequently, they cannot easily evaluate the potential at the boundary nodes of a boundary-element electrode model. The Fourier-domain models employ axial-symmetric ring source models, and thereby provide higher accuracy that the line source model, where the source is lumped...... including anisotropy show that the spatial models require extreme care in the integration procedure owing to the singularity in the weighting functions. With adequate sampling, the spatial models can evaluate extracellular potentials with high accuracy....

Clinic access and teenage birth rates: Racial/ethnic and spatial disparities in Houston, TX.

Science.gov (United States)

Wisniewski, Megan M; O'Connell, Heather A

2018-03-01

Teenage motherhood is a pressing issue in the United States, and one that is disproportionately affecting racial/ethnic minorities. In this research, we examine the relationship between the distance to the nearest reproductive health clinic and teenage birth rates across all zip codes in Houston, Texas. Our primary data come from the Texas Department of State Health Services. We use spatial regression analysis techniques to examine the link between clinic proximity and local teenage birth rates for all females aged 15 to 19, and separately by maternal race/ethnicity. We find, overall, limited support for a connection between clinic distance and local teenage birth rates. However, clinics seem to matter most for explaining non-Hispanic white teenage birth rates, particularly in high-poverty zip codes. The racial/ethnic and economic variation in the importance of clinic distance suggests tailoring clinic outreach to more effectively serve a wider range of teenage populations. We argue social accessibility should be considered in addition to geographic accessibility in order for clinics to help prevent teenage pregnancy. Copyright © 2018. Published by Elsevier Ltd.

The Role of Potential Agents in Making Spatial Perspective Taking Social

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Amy M Clements-Stephens

2013-09-01

Full Text Available A striking relationship between visual spatial perspective taking (VSPT and social skills has been demonstrated for perspective-taking tasks in which the target of the imagined or inferred perspective is a potential agent, suggesting that the presence of a potential agent may create a social context for the seemingly spatial task of imagining a novel visual perspective. In a series of studies, we set out to investigate how and when a target might be viewed as sufficiently agent-like to incur a social influence on VSPT performance. By varying the perceptual and conceptual features that defined the targets as potential agents, we find that even something as simple as suggesting animacy for a simple wooden block may be sufficient. More critically, we found that experience with one potential agent influenced the performance with subsequent targets, either by inducing or eliminating the influence of social skills on VSPT performance. These carryover effects suggest that the relationship between social skills and VSPT performance is mediated by a complex relationship that includes the task, the target, and the context in which that target is perceived. These findings highlight potential problems that arise when identifying a task as belonging exclusively to a single cognitive domain and stress instead the highly interactive nature of cognitive domains and their susceptibility to cross-domain individual differences.

Medication abortion: Potential for improved patient access through pharmacies.

Science.gov (United States)

Raifman, Sarah; Orlando, Megan; Rafie, Sally; Grossman, Daniel

2018-05-08

To discuss the potential for improving access to early abortion care through pharmacies in the United States. Despite the growing use of medications to induce termination of early pregnancy, pharmacist involvement in abortion care is currently limited. The Food and Drug Administration's Risk Evaluation and Mitigation Strategy (REMS) for Mifeprex® (mifepristone 200 mg), the principal drug used in early medication abortion, prohibits the dispensing of the drug by prescription at pharmacies. This commentary reviews the pharmacology of medication abortion with the use of mifepristone and misoprostol, as well as aspects of service delivery and data on safety, efficacy, and acceptability. Given its safety record, mifepristone no longer fits the profile of a drug that requires an REMS. The recent implementation of pharmacy dispensing of mifepristone in community pharmacies in Australia and some provinces of Canada has improved access to medication abortion by increasing the number of medication abortion providers, particularly in rural areas. Provision of mifepristone in pharmacies, which involves dispensing and patient counseling, would likely improve access to early abortion in the United States without increasing risks to women. Copyright © 2018 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

Chinese Global and Russian Spatial Strategies: Harmonization Potential

Directory of Open Access Journals (Sweden)

Pavel Aleksandrovich Minakir

2017-06-01

Full Text Available A probability of the harmonization of the Chinese sub-global strategy ‘One Belt, One Road’, proposed in 2013, and Russian integration project for the Eurasia economic cooperation are reviewed as well as the influence of this potential synchronized project on the Far Eastern segment of the Russian spatial strategy. It is noted that the problems of spatial heterogeneity gave push to the ‘One Belt, One Road’ project when China approached the point in economic development where different regional economic zones demand new infrastructural solutions for maintaining economic dynamics. The article shows that the declared co-development of countries involved is based on the rigid pragmatic financial-credit and infrastructural expansion of Central Asian model: mandatory provision of significant share in property (controlling stake, if possible, mandatory financing with construction contract and guaranteed future export of services for operating the facilities, ensuring the rights on full (or no less than 50% export of raw materials for further processing to China, employing Chinese labor in Russian-Chinese enterprises, and using Chinese machinery and equipment

Chromatic and Achromatic Spatial Resolution of Local Field Potentials in Awake Cortex.

Science.gov (United States)

Jansen, Michael; Li, Xiaobing; Lashgari, Reza; Kremkow, Jens; Bereshpolova, Yulia; Swadlow, Harvey A; Zaidi, Qasim; Alonso, Jose-Manuel

2015-10-01

Local field potentials (LFPs) have become an important measure of neuronal population activity in the brain and could provide robust signals to guide the implant of visual cortical prosthesis in the future. However, it remains unclear whether LFPs can detect weak cortical responses (e.g., cortical responses to equiluminant color) and whether they have enough visual spatial resolution to distinguish different chromatic and achromatic stimulus patterns. By recording from awake behaving macaques in primary visual cortex, here we demonstrate that LFPs respond robustly to pure chromatic stimuli and exhibit ∼2.5 times lower spatial resolution for chromatic than achromatic stimulus patterns, a value that resembles the ratio of achromatic/chromatic resolution measured with psychophysical experiments in humans. We also show that, although the spatial resolution of LFP decays with visual eccentricity as is also the case for single neurons, LFPs have higher spatial resolution and show weaker response suppression to low spatial frequencies than spiking multiunit activity. These results indicate that LFP recordings are an excellent approach to measure spatial resolution from local populations of neurons in visual cortex including those responsive to color. © The Author 2014. Published by Oxford University Press.

Integrative Spatial Data Analytics for Public Health Studies of New York State.

Science.gov (United States)

Chen, Xin; Wang, Fusheng

2016-01-01

Increased accessibility of health data made available by the government provides unique opportunity for spatial analytics with much higher resolution to discover patterns of diseases, and their correlation with spatial impact indicators. This paper demonstrated our vision of integrative spatial analytics for public health by linking the New York Cancer Mapping Dataset with datasets containing potential spatial impact indicators. We performed spatial based discovery of disease patterns and variations across New York State, and identify potential correlations between diseases and demographic, socio-economic and environmental indicators. Our methods were validated by three correlation studies: the correlation between stomach cancer and Asian race, the correlation between breast cancer and high education population, and the correlation between lung cancer and air toxics. Our work will allow public health researchers, government officials or other practitioners to adequately identify, analyze, and monitor health problems at the community or neighborhood level for New York State.

A geo-spatial data management system for potentially active volcanoes—GEOWARN project

Science.gov (United States)

Gogu, Radu C.; Dietrich, Volker J.; Jenny, Bernhard; Schwandner, Florian M.; Hurni, Lorenz

2006-02-01

Integrated studies of active volcanic systems for the purpose of long-term monitoring and forecast and short-term eruption prediction require large numbers of data-sets from various disciplines. A modern database concept has been developed for managing and analyzing multi-disciplinary volcanological data-sets. The GEOWARN project (choosing the "Kos-Yali-Nisyros-Tilos volcanic field, Greece" and the "Campi Flegrei, Italy" as test sites) is oriented toward potentially active volcanoes situated in regions of high geodynamic unrest. This article describes the volcanological database of the spatial and temporal data acquired within the GEOWARN project. As a first step, a spatial database embedded in a Geographic Information System (GIS) environment was created. Digital data of different spatial resolution, and time-series data collected at different intervals or periods, were unified in a common, four-dimensional representation of space and time. The database scheme comprises various information layers containing geographic data (e.g. seafloor and land digital elevation model, satellite imagery, anthropogenic structures, land-use), geophysical data (e.g. from active and passive seismicity, gravity, tomography, SAR interferometry, thermal imagery, differential GPS), geological data (e.g. lithology, structural geology, oceanography), and geochemical data (e.g. from hydrothermal fluid chemistry and diffuse degassing features). As a second step based on the presented database, spatial data analysis has been performed using custom-programmed interfaces that execute query scripts resulting in a graphical visualization of data. These query tools were designed and compiled following scenarios of known "behavior" patterns of dormant volcanoes and first candidate signs of potential unrest. The spatial database and query approach is intended to facilitate scientific research on volcanic processes and phenomena, and volcanic surveillance.

Effect of Spatial Dimension and External Potential on Joule-Thomson Coefficients of Ideal Bose Gases

International Nuclear Information System (INIS)

Yuan Duqi; Wang Canjun

2010-01-01

Based on the form of the n-dimensional generic power-law potential, the state equation and the heat capacity, the analytical expressions of the Joule-Thomson coefficient (JTC) for an ideal Bose gas are derived in n-dimensional potential. The effect of the spatial dimension and the external potential on the JTC are discussed, respectively. These results show that: (i) For the free ideal Bose gas, when n/s ≤ 2 (n is the spatial dimension, s is the momentum index in the relation between the energy and the momentum), and T → T C (T C is the critical temperature), the JTC can obviously improve by means of changing the throttle valve's shape and decreasing the spatial dimension of gases. (ii) For the inhomogeneous external potential, the discriminant Δ = [1 - Π[ n i=1 (kT/varpi i ) 1/t i Γ(1/t i + 1)] (k is the Boltzmann Constant, T is the thermodynamic temperature, varpi i is the external field's energy), is obtained. The potential makes the JTC increase when Δ > 0, on the contrary, it makes the JTC decrease when Δ i < 1. (general)

Using the integrated rural mobility and access (IRMA) approach in prospering rural South Africa

CSIR Research Space (South Africa)

Chakwizira, J

2008-11-01

Full Text Available settlements implications of current rural development approaches are outlined. The potential and impact of the integrated rural mobility and access approach (IRMA) in unlocking socio-economic and spatial livelihood opportunities are discussed. In this regard...

The potential use of mobile technology: enhancing accessibility and communication in a blended learning course

Directory of Open Access Journals (Sweden)

Tabisa Mayisela

2013-01-01

Full Text Available Mobile technology is increasingly being used to support blended learning beyond computer centres. It has been considered as a potential solution to the problem of a shortage of computers for accessing online learning materials (courseware in a blended learning course. The purpose of the study was to establish how the use of mobile technology could enhance accessibility and communication in a blended learning course. Data were solicitedfrom a purposive convenience sample of 36 students engaged in the blended learning course. The case study utilized a mixed-methods approach. An unstructured interview was conducted with the course lecturer and these data informed the design of the students' semi-structured questionnaire. It was found that students with access to mobile technology had an increased opportunity to access the courseware of the blended learning course. Mobile technology further enhanced student-to-student and student-to-lecturer communication by means of social networks. The study concludes that mobile technology has the potential to increase accessibility and communication in a blended learning course. Recommendations, limitations of the present study, and suggestionsforfuture research were made.

Healthcare Access for Iraqi Refugee Children in Texas: Persistent Barriers, Potential Solutions, and Policy Implications.

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Vermette, David; Shetgiri, Rashmi; Al Zuheiri, Haidar; Flores, Glenn

2015-10-01

To identify access barriers to healthcare and potential interventions to improve access for Iraqi refugee children. Four focus groups were conducted using consecutive sampling of Iraqi refugee parents residing in the US for 8 months to 5 years. Eight key-informant interviews also were conducted with employees of organizations serving Iraqi refugee families, recruited using snowball sampling. Focus groups and interviews were audiotaped, transcribed, and analyzed using margin coding and grounded theory. Iraqi refugees identified provider availability, Medicaid maintenance and renewal, language issues, and inadequate recognition of post-traumatic stress disorder as barriers to care for their children. Interviewees cited loss of case-management services and difficulties in understanding the Medicaid renewal process as barriers. Potential interventions to improve access include community-oriented efforts to educate parents on Medicaid renewal, obtaining services, and accessing specialists. Given the enduring nature of language and Medicaid renewal barriers, policies addressing eligibility alone are insufficient.

The potential of diffraction grating for spatial applications

Science.gov (United States)

Jourlin, Y.; Parriaux, O.; Pigeon, F.; Tischenko, A. V.

2017-11-01

Diffraction gratings are know, and have been fabricated for more than one century. They are now making a come back for two reasons: first, because they are now better understood which leads to the efficient exploitation of what was then called their "anomalies"; secondly, because they are now fabricable by means of the modern manufacturing potential of planar technologies. Novel grating can now perform better than conventional gratings, and address new application fields which were not expected to be theirs. This is the case of spatial applications where they can offer multiple optical functions, low size, low weight and mechanical robustness. The proposed contribution will briefly discuss the use of gratings for spatial applications. One of the most important applications is in the measurement of displacement. Usual translation and rotation sensors are bulky devices, which impose a system breakdown leading to cumbersome and heavy assemblies. We are proposing a miniaturized version of the traditional moving grating technique using submicron gratings and a specific OptoASIC which enables the measurement function to be non-obtrusively inserted into light and compact electro-mechanical systems. Nanometer resolution is possible with no compromise on the length of the measurement range. Another family of spatial application is in the field of spectrometers where new grating types allow a more flexible processing of the optical spectrum. Another family of applications addresses the question of inter-satellite communications: the introduction of gratings in laser cavities or in the laser mirrors enables the stabilization of the emitted polarization, the stabilization of the frequency as well as wide range frequency sweeping without mobile parts.

Accessibility of tertiary hospitals in Finland: A comparison of administrative and normative catchment areas.

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Huotari, Tiina; Antikainen, Harri; Keistinen, Timo; Rusanen, Jarmo

2017-06-01

The determination of an appropriate catchment area for a hospital providing highly specialized (i.e. tertiary) health care is typically a trade-off between ensuring adequate client volumes and maintaining reasonable accessibility for all potential clients. This may pose considerable challenges, especially in sparsely inhabited regions. In Finland, tertiary health care is concentrated in five university hospitals, which provide services in their dedicated catchment areas. This study utilizes Geographic Information Systems (GIS), together with grid-based population data and travel-time estimates, to assess the spatial accessibility of these hospitals. The current geographical configuration of the hospitals is compared to a normative assignment, with and without capacity constraints. The aim is to define optimal catchment areas for tertiary hospitals so that their spatial accessibility is as equal as possible. The results indicate that relatively modest improvements can be achieved in accessibility by using normative assignment to determine catchment areas. Copyright © 2017 Elsevier Ltd. All rights reserved.

[Use of indicators of geographical accessibility to primary health care centers in addressing inequities].

Science.gov (United States)

De Pietri, Diana; Dietrich, Patricia; Mayo, Patricia; Carcagno, Alejandro; de Titto, Ernesto

2013-12-01

Characterize geographical indicators in relation to their usefulness in measuring regional inequities, identify and describe areas according to their degree of geographical accessibility to primary health care centers (PHCCs), and detect populations at risk from the perspective of access to primary care. Analysis of spatial accessibility using geographic information systems (GIS) involved three aspects: population without medical coverage, distribution of PHCCs, and the public transportation network connecting them. The development of indicators of demand (real, potential, and differential) and analysis of territorial factors affecting population mobility enabled the characterization of PHCCs with regard to their environment, thereby contributing to local and regional analysis and to the detection of different zones according to regional connectivity levels. Indicators developed in a GIS environment were very useful in analyzing accessibility to PHCCs by vulnerable populations. Zoning the region helped identify inequities by differentiating areas of unmet demand and fragmentation of spatial connectivity between PHCCs and public transportation.

Statistical Approaches Used to Assess the Equity of Access to Food Outlets: A Systematic Review.

Science.gov (United States)

Lamb, Karen E; Thornton, Lukar E; Cerin, Ester; Ball, Kylie

2015-01-01

Inequalities in eating behaviours are often linked to the types of food retailers accessible in neighbourhood environments. Numerous studies have aimed to identify if access to healthy and unhealthy food retailers is socioeconomically patterned across neighbourhoods, and thus a potential risk factor for dietary inequalities. Existing reviews have examined differences between methodologies, particularly focussing on neighbourhood and food outlet access measure definitions. However, no review has informatively discussed the suitability of the statistical methodologies employed; a key issue determining the validity of study findings. Our aim was to examine the suitability of statistical approaches adopted in these analyses. Searches were conducted for articles published from 2000-2014. Eligible studies included objective measures of the neighbourhood food environment and neighbourhood-level socio-economic status, with a statistical analysis of the association between food outlet access and socio-economic status. Fifty-four papers were included. Outlet accessibility was typically defined as the distance to the nearest outlet from the neighbourhood centroid, or as the number of food outlets within a neighbourhood (or buffer). To assess if these measures were linked to neighbourhood disadvantage, common statistical methods included ANOVA, correlation, and Poisson or negative binomial regression. Although all studies involved spatial data, few considered spatial analysis techniques or spatial autocorrelation. With advances in GIS software, sophisticated measures of neighbourhood outlet accessibility can be considered. However, approaches to statistical analysis often appear less sophisticated. Care should be taken to consider assumptions underlying the analysis and the possibility of spatially correlated residuals which could affect the results.

Statistical Approaches Used to Assess the Equity of Access to Food Outlets: A Systematic Review

Directory of Open Access Journals (Sweden)

Karen E. Lamb

2015-07-01

Full Text Available BackgroundInequalities in eating behaviours are often linked to the types of food retailers accessible in neighbourhood environments. Numerous studies have aimed to identify if access to healthy and unhealthy food retailers is socioeconomically patterned across neighbourhoods, and thus a potential risk factor for dietary inequalities. Existing reviews have examined differences between methodologies, particularly focussing on neighbourhood and food outlet access measure definitions. However, no review has informatively discussed the suitability of the statistical methodologies employed; a key issue determining the validity of study findings. Our aim was to examine the suitability of statistical approaches adopted in these analyses.MethodsSearches were conducted for articles published from 2000-2014. Eligible studies included objective measures of the neighbourhood food environment and neighbourhood-level socio-economic status, with a statistical analysis of the association between food outlet access and socio-economic status.ResultsFifty-four papers were included. Outlet accessibility was typically defined as the distance to the nearest outlet from the neighbourhood centroid, or as the number of food outlets within a neighbourhood (or buffer. To assess if these measures were linked to neighbourhood disadvantage, common statistical methods included ANOVA, correlation, and Poisson or negative binomial regression. Although all studies involved spatial data, few considered spatial analysis techniques or spatial autocorrelation.ConclusionsWith advances in GIS software, sophisticated measures of neighbourhood outlet accessibility can be considered. However, approaches to statistical analysis often appear less sophisticated. Care should be taken to consider assumptions underlying the analysis and the possibility of spatially correlated residuals which could affect the results.

From spectral holeburning memory to spatial-spectral microwave signal processing

International Nuclear Information System (INIS)

Babbitt, Wm Randall; Barber, Zeb W; Harrington, Calvin; Mohan, R Krishna; Sharpe, Tia; Bekker, Scott H; Chase, Michael D; Merkel, Kristian D; Stiffler, Colton R; Traxinger, Aaron S; Woidtke, Alex J

2014-01-01

Many storage and processing systems based on spectral holeburning have been proposed that access the broad bandwidth and high dynamic range of spatial-spectral materials, but only recently have practical systems been developed that exceed the performance and functional capabilities of electronic devices. This paper reviews the history of the proposed applications of spectral holeburning and spatial-spectral materials, from frequency domain optical memory to microwave photonic signal processing systems. The recent results of a 20 GHz bandwidth high performance spectrum monitoring system with the additional capability of broadband direction finding demonstrates the potential for spatial-spectral systems to be the practical choice for solving demanding signal processing problems in the near future. (paper)

DESIGN AND IMPLEMENTATION OF AN OPEN ACCESS GEOPORTAL

OpenAIRE

SARI, Fatih

2018-01-01

GeoPortal Systems are being considered one of the most important object in interoperability concept for Spatial data Management. With the developing technology of the information age, the need for accessing to spatial data is caused to effort for establishing national, regional and local information systems by institutes and organizations. Sharing and accessing of spatial datasets between institutes and organizations are being more important within interoperability concept.In this study, Open...

Predicting Fish Growth Potential and Identifying Water Quality Constraints: A Spatially-Explicit Bioenergetics Approach

Science.gov (United States)

Budy, Phaedra; Baker, Matthew; Dahle, Samuel K.

2011-10-01

Anthropogenic impairment of water bodies represents a global environmental concern, yet few attempts have successfully linked fish performance to thermal habitat suitability and fewer have distinguished co-varying water quality constraints. We interfaced fish bioenergetics, field measurements, and Thermal Remote Imaging to generate a spatially-explicit, high-resolution surface of fish growth potential, and next employed a structured hypothesis to detect relationships among measures of fish performance and co-varying water quality constraints. Our thermal surface of fish performance captured the amount and spatial-temporal arrangement of thermally-suitable habitat for three focal species in an extremely heterogeneous reservoir, but interpretation of this pattern was initially confounded by seasonal covariation of water residence time and water quality. Subsequent path analysis revealed that in terms of seasonal patterns in growth potential, catfish and walleye responded to temperature, positively and negatively, respectively; crappie and walleye responded to eutrophy (negatively). At the high eutrophy levels observed in this system, some desired fishes appear to suffer from excessive cultural eutrophication within the context of elevated temperatures whereas others appear to be largely unaffected or even enhanced. Our overall findings do not lead to the conclusion that this system is degraded by pollution; however, they do highlight the need to use a sensitive focal species in the process of determining allowable nutrient loading and as integrators of habitat suitability across multiple spatial and temporal scales. We provide an integrated approach useful for quantifying fish growth potential and identifying water quality constraints on fish performance at spatial scales appropriate for whole-system management.

The effect of spatial barriers on realised accessibility to heath services after a natural disaster.

Science.gov (United States)

MacRae, Jayden; Kingham, Simon; Griffin, Ed

2015-09-01

The closure of the Manawatu Gorge in New Zealand in August 2011 caused a change in the travel time for patients living in the east of the MidCentral Health District to their health services located in Palmerston North. This presented an opportunity to study the effect a change in spatial access had on a population before and after such an event. We used a retrospective cohort design with routinely collected data from general practice and hospital services. Realised accessibility was calculated for 101,456 patients over 3.5 years. General practice utilization appeared to be the only service affected negatively during the gorge closure (rate ratio 1.106). Outpatient attendances had an increase in use by those with increased travel time (rate ratio 0.922). There was evidence of other unidentified factors that impacted the use of services across both intervention and control groups between the gorge open and closed periods. These results were more conservative than those produced by a traditional uncontrolled travel time category analysis which suggested a correlation in non-urgent ED attendance and general practice and boundary effects in all ED attendances and hospital admissions. Copyright © 2015 Elsevier Ltd. All rights reserved.

Association between neighborhood need and spatial access to food stores and fast food restaurants in neighborhoods of colonias.

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Sharkey, Joseph R; Horel, Scott; Han, Daikwon; Huber, John C

2009-02-16

To determine the extent to which neighborhood needs (socioeconomic deprivation and vehicle availability) are associated with two criteria of food environment access: 1) distance to the nearest food store and fast food restaurant and 2) coverage (number) of food stores and fast food restaurants within a specified network distance of neighborhood areas of colonias, using ground-truthed methods. Data included locational points for 315 food stores and 204 fast food restaurants, and neighborhood characteristics from the 2000 U.S. Census for the 197 census block group (CBG) study area. Neighborhood deprivation and vehicle availability were calculated for each CBG. Minimum distance was determined by calculating network distance from the population-weighted center of each CBG to the nearest supercenter, supermarket, grocery, convenience store, dollar store, mass merchandiser, and fast food restaurant. Coverage was determined by calculating the number of each type of food store and fast food restaurant within a network distance of 1, 3, and 5 miles of each population-weighted CBG center. Neighborhood need and access were examined using Spearman ranked correlations, spatial autocorrelation, and multivariate regression models that adjusted for population density. Overall, neighborhoods had best access to convenience stores, fast food restaurants, and dollar stores. After adjusting for population density, residents in neighborhoods with increased deprivation had to travel a significantly greater distance to the nearest supercenter or supermarket, grocery store, mass merchandiser, dollar store, and pharmacy for food items. The results were quite different for association of need with the number of stores within 1 mile. Deprivation was only associated with fast food restaurants; greater deprivation was associated with fewer fast food restaurants within 1 mile. CBG with greater lack of vehicle availability had slightly better access to more supercenters or supermarkets, grocery

Association between neighborhood need and spatial access to food stores and fast food restaurants in neighborhoods of Colonias

Directory of Open Access Journals (Sweden)

Han Daikwon

2009-02-01

Full Text Available Abstract Objective To determine the extent to which neighborhood needs (socioeconomic deprivation and vehicle availability are associated with two criteria of food environment access: 1 distance to the nearest food store and fast food restaurant and 2 coverage (number of food stores and fast food restaurants within a specified network distance of neighborhood areas of colonias, using ground-truthed methods. Methods Data included locational points for 315 food stores and 204 fast food restaurants, and neighborhood characteristics from the 2000 U.S. Census for the 197 census block group (CBG study area. Neighborhood deprivation and vehicle availability were calculated for each CBG. Minimum distance was determined by calculating network distance from the population-weighted center of each CBG to the nearest supercenter, supermarket, grocery, convenience store, dollar store, mass merchandiser, and fast food restaurant. Coverage was determined by calculating the number of each type of food store and fast food restaurant within a network distance of 1, 3, and 5 miles of each population-weighted CBG center. Neighborhood need and access were examined using Spearman ranked correlations, spatial autocorrelation, and multivariate regression models that adjusted for population density. Results Overall, neighborhoods had best access to convenience stores, fast food restaurants, and dollar stores. After adjusting for population density, residents in neighborhoods with increased deprivation had to travel a significantly greater distance to the nearest supercenter or supermarket, grocery store, mass merchandiser, dollar store, and pharmacy for food items. The results were quite different for association of need with the number of stores within 1 mile. Deprivation was only associated with fast food restaurants; greater deprivation was associated with fewer fast food restaurants within 1 mile. CBG with greater lack of vehicle availability had slightly better

Spatial Representations in Local Field Potential Activity of Primate Anterior Intraparietal Cortex (AIP.

Directory of Open Access Journals (Sweden)

Sebastian J Lehmann

Full Text Available The execution of reach-to-grasp movements in order to interact with our environment is an important subset of the human movement repertoire. To coordinate such goal-directed movements, information about the relative spatial position of target and effector (in this case the hand has to be continuously integrated and processed. Recently, we reported the existence of spatial representations in spiking-activity of the cortical fronto-parietal grasp network (Lehmann & Scherberger 2013, and in particular in the anterior intraparietal cortex (AIP. To further investigate the nature of these spatial representations, we explored in two rhesus monkeys (Macaca mulatta how different frequency bands of the local field potential (LFP in AIP are modulated by grip type, target position, and gaze position, during the planning and execution of reach-to-grasp movements. We systematically varied grasp type, spatial target, and gaze position and found that both spatial and grasp information were encoded in a variety of frequency bands (1-13Hz, 13-30Hz, 30-60Hz, and 60-100Hz, respectively. Whereas the representation of grasp type strongly increased towards and during movement execution, spatial information was represented throughout the task. Both spatial and grasp type representations could be readily decoded from all frequency bands. The fact that grasp type and spatial (reach information was found not only in spiking activity, but also in various LFP frequency bands of AIP, might significantly contribute to the development of LFP-based neural interfaces for the control of upper limb prostheses.

Accessibility and spatial distribution of general practice services in an Australian city by levels of social disadvantage.

Science.gov (United States)

Hyndman, J C; Holman, C D

2001-12-01

The accessibility and spatial distribution of health services provided by the main source of primary medical care in Australia--the general practice surgery--was investigated by level of social disadvantage of local catchment areas. All 459 general practice surgeries in Perth, an Australian city of 1.2 million residents, were surveyed with a 94% response. Amount of service provision was measured using weekly doctor-hours, available from consulting rooms during opening hours, and associated nurse-hours of service. Access factors were defined as the distance to the nearest surgery, provision of Sunday and evening services, ease of making a same day appointment, bulk-billing, and whether the surgery offered a choice of gender of doctor. There were relatively more surgeries in disadvantaged areas and doctor-hours of service provision were also greater (41.0 h/1,000 most disadvantaged vs. 37.9 h/1000 least disadvantaged). Bulk-billing care, at no direct cost to the patient, was more likely to be provided in most disadvantaged areas compared with least disadvantaged areas (61 vs. 38%). However, populations living in the most disadvantaged areas were less likely to be able to see the local GP at short notice (91 vs. 95%), to have access to a local female GP (56 vs. 62%) or a local service in the evenings (42 vs. 51%). While the overall picture of accessibility was favourable, there was considerable variation in the type of services provided to different socioeconomic groups. Health care planners should investigate the reasons for these differences and advise Government to ensure that access factors affecting publicly funded services are equitably distributed.

Model development for spatial variation of PM2.5 emissions from residential wood burning

International Nuclear Information System (INIS)

Yong Q, Tian; Peng Gong; Qian Yu; Radke, John D.

2004-01-01

This paper presents a preliminary research result of spatially quantifying and allocating the potential activity of residential wood burning (RWB) by using demographic, hypsographic, climatic and topographic information as independent variables. We also introduce the method for calculating PM 2.5 emission from residential wood combustion with the potential activity as primary variable. A linear regression model was generated to describe spatial and temporal distribution of the potential activity of wood burning as primary heating source. In order to improve the estimation, the classifications of urban, suburban and rural were redefined to meet the specifications of this application. Also, a unique way of defining forest accessibility is found useful in estimating the activity potential of RWB. The results suggest that the potential activity of wood burning is mostly determined by elevation of a location, forest accessibility, urban/non-urban position, climatic conditions and several demographic variables. The analysis results were validated using survey data collected through face-to-face and telephone interviews over the study area in central California. The linear regression model can explain approximately 86% of the variation of surveyed wood burning activity potential. The total PM 2.5 emitted from woodstoves and fireplaces is analyzed for the study region at county level. (Author)

elevatr: Access Elevation Data from Various APIs | Science ...

Science.gov (United States)

Several web services are available that provide access to elevation data. This package provides access to several of those services and returns elevation data either as a SpatialPointsDataFrame from point elevation services or as a raster object from raster elevation services. Currently, the package supports access to the Mapzen Elevation Service, Mapzen Terrain Service, and the USGS Elevation Point Query Service. The R language for statistical computing is increasingly used for spatial data analysis . This R package, elevatr, is in response to this and provides access to elevation data from various sources directly in R. The impact of `elevatr` is that it will 1) facilitate spatial analysis in R by providing access to foundational dataset for many types of analyses (e.g. hydrology, limnology) 2) open up a new set of users and uses for APIs widely used outside of R, and 3) provide an excellent example federal open source development as promoted by the Federal Source Code Policy (https://sourcecode.cio.gov/).

On the accessibility of phonological, orthographic, and semantic aspects of second language vocabulary learning and their relationship with spatial and linguistic intelligences

Directory of Open Access Journals (Sweden)

Abbas Ali Zarei

2015-01-01

Full Text Available The present study was an attempt to investigate the differences in the accessibility of phonological, semantic, and orthographic aspects of words in L2 vocabulary learning. For this purpose, a sample of 119 Iranian intermediate level EFL students in a private language institute in Karaj was selected. All of the participants received the same instructional treatment. At the end of the experimental period, three tests were administered based on the previously-taught words. A subset of Gardner’s’ (1983 Multiple Intelligences questionnaire was also used for data collection. A repeated measures one-way ANOVA procedure was used to analyze the obtained data. The results showed significant differences in the accessibility of phonological, semantic, and orthographic aspects of words in second language vocabulary learning. Moreover, to investigate the relationships between spatial and linguistic intelligences and the afore-mentioned aspects of lexical knowledge, a correlational analysis was used. No significant relationships were found between spatial and linguistic intelligences and the three aspects of lexical knowledge. These findings may have theoretical and pedagogical implications for researchers, teachers, and learners.

The influence of caffeine on spatial-selective attention: an event-related potential study.

Science.gov (United States)

Ruijter, J; de Ruiter, M B; Snel, J; Lorist, M M

2000-12-01

Following the indications of previous studies that caffeine might have a specific effect on the processing of spatial information compared with other types of information, the present study investigated the influence of caffeine on an often used spatial-selective attention task. Event-related potentials (ERPs) were recorded from 11 participants under conditions of caffeine (250 mg) and placebo. Spatial-selective attention effects were reflected in the ERPs as more positive going occipital P1 and broadly distributed P2 components, and more negative going occipital-temporal N1 and broadly distributed N2 components. A treatment effect was found as a more positive going frontal P2 component in the caffeine condition, whereas interactions between treatment and attention were observed for P2 and N2 components, but not for P1 and N1 components. This pattern of results suggests that caffeine has no specific influence on spatial-selective attention, but rather, has a more general facilitating effect on perceptual processing, as well as a possible effect on the frontal control mechanisms, i.e. focusing attention and increasing selectivity.

Framework development for providing accessibility to qualitative spatial calculi

OpenAIRE

Jan, Sahib

2011-01-01

Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies. Qualitative spatial reasoning deals with knowledge about an infinite spatial domain using a finite set of qualitative relations without using numerical computation. Qualitative knowledge is relative knowledge where we obtain the knowledge on the basis of comparison of features with in the object domain rather then using some external scales. Reasoning is an inte...

The Relative Importance of Spatial Versus Temporal Structure in the Perception of Biological Motion: An Event-Related Potential Study

Science.gov (United States)

Hirai, Masahiro; Hiraki, Kazuo

2006-01-01

We investigated how the spatiotemporal structure of animations of biological motion (BM) affects brain activity. We measured event-related potentials (ERPs) during the perception of BM under four conditions: normal spatial and temporal structure; scrambled spatial and normal temporal structure; normal spatial and scrambled temporal structure; and…

Spatial preference heterogeneity in forest recreation

DEFF Research Database (Denmark)

Abildtrup, Jens; Garcia, Serge; Olsen, Søren Bøye

2013-01-01

In this study, we analyze the preferences for recreational use of forests in Lorraine (Northeastern France), applying stated preference data. Our approach allows us to estimate individual-specific preferences for recreational use of different forest types. These estimates are used in a second stage...... in the estimation of welfare economic values for parking and picnic facilities in the analyzed model. The results underline the importance of considering spatial heterogeneity of preferences carrying out economic valuation of spatial-delineated environmental goods and that the spatial variation in willingness...... of the analysis where we test whether preferences depend on access to recreation sites. We find that there is significant preference heterogeneity with respect to most forest attributes. The spatial analysis shows that preferences for forests with parking and picnic facilities are correlated with having access...

Melatonin administration impairs visuo-spatial performance and inhibits neocortical long-term potentiation in rats.

Science.gov (United States)

Soto-Moyano, Rubén; Burgos, Héctor; Flores, Francisco; Valladares, Luis; Sierralta, Walter; Fernández, Victor; Pérez, Hernán; Hernández, Paula; Hernández, Alejandro

2006-10-01

Melatonin has been shown to inhibit long-term potentiation (LTP) in hippocampal slices of rats. Since LTP may be one of the main mechanisms by which memory traces are encoded and stored in the central nervous system, it is possible that melatonin could modulate cognitive performance by interfering with the cellular and/or molecular mechanisms involved in LTP. We investigated in rats the effects of intraperitoneally-administered melatonin (0.1, 1 and 10 mg/kg), its saline-ethanol solvent, or saline alone, on the acquisition of visuo-spatial memory as well as on the ability of the cerebral cortex to develop LTP in vivo. Visuo-spatial performance was assessed daily in rats, for 10 days, in an 8-arm radial maze, 30 min after they received a single daily dose of melatonin. Visual cortex LTP was determined in sodium pentobarbital anesthetized rats (65 mg/kg i.p.), by potentiating transcallosal evoked responses with a tetanizing train (312 Hz, 500 ms duration) 30 min after administration of a single dose of melatonin. Results showed that melatonin impaired visuo-spatial performance in rats, as revealed by the greater number of errors committed and time spent to solve the task in the radial maze. Melatonin also prevented the induction of neocortical LTP. It is concluded that melatonin, at the doses utilized in this study, could alter some forms of neocortical plasticity involved in short- and long-term visuo-spatial memories in rats.

Chromatic spatial contrast sensitivity estimated by visual evoked cortical potential and psychophysics

Science.gov (United States)

Barboni, M.T.S.; Gomes, B.D.; Souza, G.S.; Rodrigues, A.R.; Ventura, D.F.; Silveira, L.C.L.

2013-01-01

The purpose of the present study was to measure contrast sensitivity to equiluminant gratings using steady-state visual evoked cortical potential (ssVECP) and psychophysics. Six healthy volunteers were evaluated with ssVECPs and psychophysics. The visual stimuli were red-green or blue-yellow horizontal sinusoidal gratings, 5° × 5°, 34.3 cd/m2 mean luminance, presented at 6 Hz. Eight spatial frequencies from 0.2 to 8 cpd were used, each presented at 8 contrast levels. Contrast threshold was obtained by extrapolating second harmonic amplitude values to zero. Psychophysical contrast thresholds were measured using stimuli at 6 Hz and static presentation. Contrast sensitivity was calculated as the inverse function of the pooled cone contrast threshold. ssVECP and both psychophysical contrast sensitivity functions (CSFs) were low-pass functions for red-green gratings. For electrophysiology, the highest contrast sensitivity values were found at 0.4 cpd (1.95 ± 0.15). ssVECP CSF was similar to dynamic psychophysical CSF, while static CSF had higher values ranging from 0.4 to 6 cpd (P chromatic functions showed no specific tuning shape; however, at high spatial frequencies the evoked potentials showed higher contrast sensitivity than the psychophysical methods (P chromatic red-green CSFs in agreement with psychophysical thresholds, mainly if the same temporal properties are applied to the stimulus. For blue-yellow CSF, correlation between electrophysiology and psychophysics was poor at high spatial frequency, possibly due to a greater effect of chromatic aberration on this kind of stimulus. PMID:23369980

Accessibility to health care facilities in Montreal Island: an application of relative accessibility indicators from the perspective of senior and non-senior residents

Directory of Open Access Journals (Sweden)

Morency Catherine

2010-10-01

significantly less mobile than people of other age cohorts. The combination of average trip length estimates with the spatial distribution of health care facilities indicates that despite being more mobile, suburban residents tend to have lower levels of accessibility compared to central city residents. The effect is more marked for seniors. Furthermore, the results indicate that accessibility calculated using a fixed bandwidth would produce patterns of exposure to health care facilities that would be difficult to achieve for suburban seniors given actual mobility patterns. Conclusions The analysis shows large disparities in accessibility between seniors and non-seniors, between urban and suburban seniors, and between vehicle owning and non-owning seniors. This research was concerned with potential accessibility levels. Follow up research could consider the results reported here to select case studies of actual access and usage of health care facilities, and related health outcomes.

a Study on Variations of Shoreline Changes and Temporal-Spatial Potentiality for Cloud Seeding at Urumia Lake

Science.gov (United States)

Agha Taher, R.; Jafari, M.; Fallah, M.; Alavi, A.

2015-12-01

time period has been used. In order to reach better results, images from MODIS satellite has been used as auxiliary data for the images that are with an error margin. Initial classification on the images was conducted to distinguish water and non water applications. Neural network classification was applied with specific scales on the images and the two major applications were thereby extracted. Then, in order to authenticate the proceedings, Error matrix and Kappa coefficient has been applied on the classified images. Base pixel method of neural network was used for the purpose of information extraction while authenticity of that was evaluated too. The outcomes display the trend of Urmia shoreline has been approximately constant between the years of 1976 to 1995 and has experienced very low variations. In 1998 the lake experienced increase of water and therefore advancement of the shoreline of the lake due to increase of precipitation and the volume of inflowing water to the basin. During 2000 to 20125, however, the lake's shoreline has experienced a downward trend, which was intensified in 2007 and reached to its most critical level ever since, that is decreasing to about one third. Further, temporal and spatial potentiality evaluation of clouds seeding in Urmia lake zone has been studied as a solution for improvement and recovery of the current status of the lake, and an algorithm was proposed for optimized temporal- spatial study on could seeding. Ecological, meteorological and synoptic data were used for timing study of the cloud's seeding plan, which upon study; it is easy to evaluate precipitation potential and quality of the system. At the next step, the rate of humidity and also stability of the precipitating system can be analyzed using radar acquired data. Whereas extracted date from MODIS images are expressing the spatial position, therefore in order to study the location of the cloud's seeding, MODIS images of the selected time intervals along with

A STUDY ON VARIATIONS OF SHORELINE CHANGES AND TEMPORAL-SPATIAL POTENTIALITY FOR CLOUD SEEDING AT URUMIA LAKE

Directory of Open Access Journals (Sweden)

R. Agha Taher

2015-12-01

+ sensors in the 35 time period has been used. In order to reach better results, images from MODIS satellite has been used as auxiliary data for the images that are with an error margin. Initial classification on the images was conducted to distinguish water and non water applications. Neural network classification was applied with specific scales on the images and the two major applications were thereby extracted. Then, in order to authenticate the proceedings, Error matrix and Kappa coefficient has been applied on the classified images. Base pixel method of neural network was used for the purpose of information extraction while authenticity of that was evaluated too. The outcomes display the trend of Urmia shoreline has been approximately constant between the years of 1976 to 1995 and has experienced very low variations. In 1998 the lake experienced increase of water and therefore advancement of the shoreline of the lake due to increase of precipitation and the volume of inflowing water to the basin. During 2000 to 20125, however, the lake’s shoreline has experienced a downward trend, which was intensified in 2007 and reached to its most critical level ever since, that is decreasing to about one third. Further, temporal and spatial potentiality evaluation of clouds seeding in Urmia lake zone has been studied as a solution for improvement and recovery of the current status of the lake, and an algorithm was proposed for optimized temporal- spatial study on could seeding. Ecological, meteorological and synoptic data were used for timing study of the cloud’s seeding plan, which upon study; it is easy to evaluate precipitation potential and quality of the system. At the next step, the rate of humidity and also stability of the precipitating system can be analyzed using radar acquired data. Whereas extracted date from MODIS images are expressing the spatial position, therefore in order to study the location of the cloud’s seeding, MODIS images of the selected time

Potential and flux field landscape theory. II. Non-equilibrium thermodynamics of spatially inhomogeneous stochastic dynamical systems

International Nuclear Information System (INIS)

Wu, Wei; Wang, Jin

2014-01-01

We have established a general non-equilibrium thermodynamic formalism consistently applicable to both spatially homogeneous and, more importantly, spatially inhomogeneous systems, governed by the Langevin and Fokker-Planck stochastic dynamics with multiple state transition mechanisms, using the potential-flux landscape framework as a bridge connecting stochastic dynamics with non-equilibrium thermodynamics. A set of non-equilibrium thermodynamic equations, quantifying the relations of the non-equilibrium entropy, entropy flow, entropy production, and other thermodynamic quantities, together with their specific expressions, is constructed from a set of dynamical decomposition equations associated with the potential-flux landscape framework. The flux velocity plays a pivotal role on both the dynamic and thermodynamic levels. On the dynamic level, it represents a dynamic force breaking detailed balance, entailing the dynamical decomposition equations. On the thermodynamic level, it represents a thermodynamic force generating entropy production, manifested in the non-equilibrium thermodynamic equations. The Ornstein-Uhlenbeck process and more specific examples, the spatial stochastic neuronal model, in particular, are studied to test and illustrate the general theory. This theoretical framework is particularly suitable to study the non-equilibrium (thermo)dynamics of spatially inhomogeneous systems abundant in nature. This paper is the second of a series

Lunar archive panoramas: modern image processing and access to the historic data based on spatial context

Science.gov (United States)

Kozlova, Natalia; Kokhanov, Alexander; Oberst, Jürgen; Zubarev, Anatoliy; Nadezhdina, Irina; Patraty, Vyacheslav; Karachevtseva, Irina; Garov, Andrey; Matveev, Evgeniy

The objectives of our work are to fully exploit the historic Soviet Lunokhod data and use the results for scientific and public purposes. Unfortunately, many of the relevant operational parameters of the Lunokhods missions are lost. Modern photogrammetry is a key to solving these issues, providing analysis techniques, not available at the time of the early lunar missions. For this purpose we use special developed software, GIS tools and high-resolution LRO data [1]. Results of new image processing of historic data are part of PRoViDE project (Planetary Robotics Vision Data Exploitation) which aims to assemble a major portion of the imaging data gathered from different vehicles and probes on planetary surfaces into a unique database, bringing them into a spatial context and providing access to a complete set of 3D vision products (http://www.provide-space.eu/). Our technology of archive panorama processing allows us to recover lost information of Soviet lunar missions and study lunar landing site imagery by state-of-the-art photogrammetric techniques. Our main task is to perform lunar panoramas in measurement form based on photogrammetry and geoanalyses methods, and then involve them in more detailed morphometric analyses [2] and 3D-modeling of lunar surface based on LROC NAC image processing [3]. The results of our work are various types of new products: panoramas in different projections, updated metadata with recovering parameters, and ortho-panoramas, which can be used for quantitative geomorphology assessment based on spatial tools [4]. All data products obtained as a result of the study are to be placed into Planetary data storage which is developing as Geodesy and Cartography Node [5]. Access to archive lunar data will be organized via Geo-portal (http://cartsrv.mexlab.ru/geoportal/) using authorization service, which provided data security and user control. Planetary spatial information system can integrate various types of data for planets and their

The potential use of mobile technology: enhancing accessibility and communication in a blended learning course

OpenAIRE

Mayisela, Tabisa

2013-01-01

Mobile technology is increasingly being used to support blended learning beyond computer centres. It has been considered as a potential solution to the problem of a shortage of computers for accessing online learning materials (courseware) in a blended learning course. The purpose of the study was to establish how the use of mobile technology could enhance accessibility and communication in a blended learning course. Data were solicitedfrom a purposive convenience sample of 36 students engage...

Internet-accessible real-time weather information system

Digital Repository Service at National Institute of Oceanography (India)

Desai, R.G.P.; Joseph, A.; Desa, E.; Mehra, P.; Desa, E.; Gouveia, A.D.

An internet-accessible real-time weather information system has been developed. This system provides real-time accessibility to weather information from a multitude of spatially distributed weather stations. The Internet connectivity also offers...

Gbm.auto: A software tool to simplify spatial modelling and Marine Protected Area planning

Science.gov (United States)

Officer, Rick; Clarke, Maurice; Reid, David G.; Brophy, Deirdre

2017-01-01

Boosted Regression Trees. Excellent for data-poor spatial management but hard to use Marine resource managers and scientists often advocate spatial approaches to manage data-poor species. Existing spatial prediction and management techniques are either insufficiently robust, struggle with sparse input data, or make suboptimal use of multiple explanatory variables. Boosted Regression Trees feature excellent performance and are well suited to modelling the distribution of data-limited species, but are extremely complicated and time-consuming to learn and use, hindering access for a wide potential user base and therefore limiting uptake and usage. BRTs automated and simplified for accessible general use with rich feature set We have built a software suite in R which integrates pre-existing functions with new tailor-made functions to automate the processing and predictive mapping of species abundance data: by automating and greatly simplifying Boosted Regression Tree spatial modelling, the gbm.auto R package suite makes this powerful statistical modelling technique more accessible to potential users in the ecological and modelling communities. The package and its documentation allow the user to generate maps of predicted abundance, visualise the representativeness of those abundance maps and to plot the relative influence of explanatory variables and their relationship to the response variables. Databases of the processed model objects and a report explaining all the steps taken within the model are also generated. The package includes a previously unavailable Decision Support Tool which combines estimated escapement biomass (the percentage of an exploited population which must be retained each year to conserve it) with the predicted abundance maps to generate maps showing the location and size of habitat that should be protected to conserve the target stocks (candidate MPAs), based on stakeholder priorities, such as the minimisation of fishing effort displacement. Gbm

Availability and accessibility of subsidized mammogram screening program in peninsular Malaysia: A preliminary study using travel impedance approach.

Science.gov (United States)

Mahmud, Aidalina; Aljunid, Syed Mohamed

2018-01-01

Access to healthcare is essential in the pursuit of universal health coverage. Components of access are availability, accessibility (spatial and non-spatial), affordability and acceptability. Measuring spatial accessibility is common approach to evaluating access to health care. This study aimed to determine the availability and spatial accessibility of subsidised mammogram screening in Peninsular Malaysia. Availability was determined from the number and distribution of facilities. Spatial accessibility was determined using the travel impedance approach to represent the revealed access as opposed to potential access measured by other spatial measurement methods. The driving distance of return trips from the respondent's residence to the facilities was determined using a mapping application. The travel expenditure was estimated by multiplying the total travel distance by a standardised travel allowance rate, plus parking fees. Respondents in this study were 344 breast cancer patients who received treatment at 4 referral hospitals between 2015 and 2016. In terms of availability, there were at least 6 major entities which provided subsidised mammogram programs. Facilities with mammogram involved with these programs were located more densely in the central and west coast region of the Peninsula. The ratio of mammogram facility to the target population of women aged 40-74 years ranged between 1: 10,000 and 1:80,000. In terms of accessibility, of the 3.6% of the respondents had undergone mammogram screening, their mean travel distance was 53.4 km (SD = 34.5, range 8-112 km) and the mean travel expenditure was RM 38.97 (SD = 24.00, range RM7.60-78.40). Among those who did not go for mammogram screening, the estimated travel distance and expenditure had a skewed distribution with median travel distance of 22.0 km (IQR 12.0, 42.0, range 2.0-340.0) and the median travel cost of RM 17.40 (IQR 10.40, 30.00, range 3.40-240.00). Higher travel impedance was noted among those who

Multisensory Integration Affects Visuo-Spatial Working Memory

Science.gov (United States)

Botta, Fabiano; Santangelo, Valerio; Raffone, Antonino; Sanabria, Daniel; Lupianez, Juan; Belardinelli, Marta Olivetti

2011-01-01

In the present study, we investigate how spatial attention, driven by unisensory and multisensory cues, can bias the access of information into visuo-spatial working memory (VSWM). In a series of four experiments, we compared the effectiveness of spatially-nonpredictive visual, auditory, or audiovisual cues in capturing participants' spatial…

Pitfalls and potential of particle swarm optimization for contemporary spatial forest planning

Energy Technology Data Exchange (ETDEWEB)

Shan, Y.; Bettinger, P.; Cieszewski, C.; Wang, W.

2012-07-01

We describe here an example of applying particle swarm optimization (PSO) a population-based heuristic technique to maximize the net present value of a contemporary southern United States forest plan that includes spatial constraints (green-up and adjacency) and wood flow constraints. When initiated with randomly defined feasible initial conditions, and tuned with some appropriate modifications, the PSO algorithm gradually converged upon its final solution and provided reasonable objective function values. However, only 86% of the global optimal value could be achieved using the modified PSO heuristic. The results of this study suggest that under random-start initial population conditions the PSO heuristic may have rather limited application to forest planning problems with economic objectives, wood-flow constraints, and spatial considerations. Pitfalls include the need to modify the structure of PSO to both address spatial constraints and to repair particles, and the need to modify some of the basic assumptions of PSO to better address contemporary forest planning problems. Our results, and hence our contributions, are contrary to earlier work that illustrated the impressive potential of PSO when applied to stand-level forest planning problems or when applied to a high quality initial population. (Author) 46 refs.

Improving spatial prediction of Schistosoma haematobium prevalence in southern Ghana through new remote sensors and local water access profiles.

Science.gov (United States)

Kulinkina, Alexandra V; Walz, Yvonne; Koch, Magaly; Biritwum, Nana-Kwadwo; Utzinger, Jürg; Naumova, Elena N

2018-06-04

Schistosomiasis is a water-related neglected tropical disease. In many endemic low- and middle-income countries, insufficient surveillance and reporting lead to poor characterization of the demographic and geographic distribution of schistosomiasis cases. Hence, modeling is relied upon to predict areas of high transmission and to inform control strategies. We hypothesized that utilizing remotely sensed (RS) environmental data in combination with water, sanitation, and hygiene (WASH) variables could improve on the current predictive modeling approaches. Schistosoma haematobium prevalence data, collected from 73 rural Ghanaian schools, were used in a random forest model to investigate the predictive capacity of 15 environmental variables derived from RS data (Landsat 8, Sentinel-2, and Global Digital Elevation Model) with fine spatial resolution (10-30 m). Five methods of variable extraction were tested to determine the spatial linkage between school-based prevalence and the environmental conditions of potential transmission sites, including applying the models to known human water contact locations. Lastly, measures of local water access and groundwater quality were incorporated into RS-based models to assess the relative importance of environmental and WASH variables. Predictive models based on environmental characterization of specific locations where people contact surface water bodies offered some improvement as compared to the traditional approach based on environmental characterization of locations where prevalence is measured. A water index (MNDWI) and topographic variables (elevation and slope) were important environmental risk factors, while overall, groundwater iron concentration predominated in the combined model that included WASH variables. The study helps to understand localized drivers of schistosomiasis transmission. Specifically, unsatisfactory water quality in boreholes perpetuates reliance of surface water bodies, indirectly increasing

A hybrid 3D spatial access method based on quadtrees and R-trees for globe data

Science.gov (United States)

Gong, Jun; Ke, Shengnan; Li, Xiaomin; Qi, Shuhua

2009-10-01

3D spatial access method for globe data is very crucial technique for virtual earth. This paper presents a brand-new maintenance method to index 3d objects distributed on the whole surface of the earth, which integrates the 1:1,000,000- scale topographic map tiles, Quad-tree and R-tree. Furthermore, when traditional methods are extended into 3d space, the performance of spatial index deteriorates badly, for example 3D R-tree. In order to effectively solve this difficult problem, a new algorithm of dynamic R-tree is put forward, which includes two sub-procedures, namely node-choosing and node-split. In the node-choosing algorithm, a new strategy is adopted, not like the traditional mode which is from top to bottom, but firstly from bottom to top then from top to bottom. This strategy can effectively solve the negative influence of node overlap. In the node-split algorithm, 2-to-3 split mode substitutes the traditional 1-to-2 mode, which can better concern the shape and size of nodes. Because of the rational tree shape, this R-tree method can easily integrate the concept of LOD. Therefore, it will be later implemented in commercial DBMS and adopted in time-crucial 3d GIS system.

Visual attention to spatial and non-spatial visual stimuli is affected differentially by age: effects on event-related brain potentials and performance data.

NARCIS (Netherlands)

Talsma, D.; Kok, A.; Ridderinkhof, K.R.

2006-01-01

To assess selective attention processes in young and old adults, behavioral and event-related potential (ERP) measures were recorded. Streams of visual stimuli were presented from left or right locations (Experiment 1) or from a central location and comprising two different spatial frequencies

Selective attention to spatial and non-spatial visual stimuli is affected differentially by age: Effects on event-related brain potentials and performance data

NARCIS (Netherlands)

Talsma, D.; Kok, Albert; Ridderinkhof, K. Richard

2006-01-01

To assess selective attention processes in young and old adults, behavioral and event-related potential (ERP) measures were recorded. Streams of visual stimuli were presented from left or right locations (Experiment 1) or from a central location and comprising two different spatial frequencies

Access to dialysis services: A systematic mapping review based on geographical information systems.

Science.gov (United States)

Hoseini, Benyamin; Bagheri, Nasser; Kiani, Behzad; Azizi, Amirabbas; Tabesh, Hamed; Tara, Mahmood

2018-05-07

Equitable access to healthcare services constitutes one of the leading priorities of healthcare provision and access to dialysis services (ADS) has an essential impact on patients depending on renal dialysis. The many existing GIS-based ADS evaluations include various spatial and non-spatial factors affecting ADS. We systematically mapped and reviewed the available literature with reference to this area identifying gaps in current GIS-based ADS measurements and developing recommendations for future studies. A threestep, systematic mapping review of the available GIS-related evidence in PubMed, Embase, Web of science, Scopus, Science Direct and IEEE Xplore was performed in May 2016 and the information collected updated October 2017 by two independent selection processes. The quality of the studies was assessed using an informal, mixed-approach scoring system. Out of 1119 literature references identified, 36 were identified and used for final review after removal of duplicates, study screenings and applying inclusion/exclusion criteria. Given the contents of the selected studies, three study groups were identified and 41 factors with potential effects on ADS determined. These studies mainly addressed the potential and/or spatial aspects of ADS. Our systematic mapping review of the evidence revealed that current GIS-based measures of ADS tend to calculate potential ADS instead of a realized one. It was also noted that listed factors affecting ADS were mainly nonspatial bringing forth the hypothesis that designing an integrated ADS index could possibly produce better ADS score than those currently advocated. Some primary and secondary research suggestions are made and a list of recommendations offered.

Access to dialysis services: A systematic mapping review based on geographical information systems

Directory of Open Access Journals (Sweden)

Benyamin Hoseini

2018-05-01

Full Text Available Equitable access to healthcare services constitutes one of the leading priorities of healthcare provision and access to dialysis services (ADS has an essential impact on patients depending on renal dialysis. The many existing GIS-based ADS evaluations include various spatial and non-spatial factors affecting ADS. We systematically mapped and reviewed the available literature with reference to this area identifying gaps in current GIS-based ADS measurements and developing recommendations for future studies. A threestep, systematic mapping review of the available GIS-related evidence in PubMed, Embase, Web of science, Scopus, Science Direct and IEEE Xplore was performed in May 2016 and the information collected updated October 2017 by two independent selection processes. The quality of the studies was assessed using an informal, mixed-approach scoring system. Out of 1119 literature references identified, 36 were identified and used for final review after removal of duplicates, study screenings and applying inclusion/exclusion criteria. Given the contents of the selected studies, three study groups were identified and 41 factors with potential effects on ADS determined. These studies mainly addressed the potential and/or spatial aspects of ADS. Our systematic mapping review of the evidence revealed that current GIS-based measures of ADS tend to calculate potential ADS instead of a realized one. It was also noted that listed factors affecting ADS were mainly nonspatial bringing forth the hypothesis that designing an integrated ADS index could possibly produce better ADS score than those currently advocated. Some primary and secondary research suggestions are made and a list of recommendations offered.

Rural and remote dental services shortages: filling the gaps through geo-spatial analysis evidence-based targeting.

Science.gov (United States)

Shiika, Yulia; Kruger, Estie; Tennant, Marc

Australia has a significant mal-distribution of its limited dental workforce. Outside the major capital cities, the distribution of accessible dental care is at best patchy. This study applied geo-spatial analysis technology to locate gaps in dental service accessibility for rural and remote dwelling Australians, in order to test the hypothesis that there are a few key location points in Australia where further dental services could make a significant contribution to ameliorating the immediate shortage crisis. A total of 2,086 dental practices were located in country areas, covering a combined catchment area of 1.84 million square kilometers, based on 50 km catchment zones around each clinic. Geo-spatial analysis technology was used to identify gaps in the accessibility of dental services for rural and remote dwelling Australians. An extraction of data was obtained to analyse the integrated geographically-aligned database. Results: Resolution of the lack of dental practices for 74 townships (of greater than 500 residents) across Australia could potentially address access for 104,000 people. An examination of the socio-economic mix found that the majority of the dental practices (84%) are located in areas classified as less disadvantaged. Output from the study provided a cohesive national map that has identified locations that could have health improvement via the targeting of dental services to that location. The study identified potential location sites for dental clinics, to address the current inequity in accessing dental services in rural and remote Australia.

Assessing the Development of Kenya National Spatial Data ...

African Journals Online (AJOL)

Spatial data plays a vital role in developmental activities, whether natural resource management or socio-economic development. Spatial Data Infrastructures (SDIs) facilitate access, sharing and dissemination of spatial data necessary for complex decision-making processes of the future. Thus, conducting SDI assessment ...

Chronic kidney disease in Nigeria: an evaluation of the spatial accessibility to healthcare for diagnosed cases in Edo State

Directory of Open Access Journals (Sweden)

Osaretin Oviasu

2016-05-01

Full Text Available Chronic kidney disease (CKD is a growing problem in Nigeria, presenting challenges to the nation’s health and economy. This study evaluates the accessibility to healthcare in Edo State of CKD patients diagnosed between 2006 and 2009. Using cost analysis techniques within a geographical information system, an estimated travel time to the hospital was used to examine the spatial accessibility of diagnosed patients to available CKD healthcare in the state. The results from the study indicated that although there was an annual rise in the number of diagnosed cases, there were no significant changes in the proportion of patients that were diagnosed at the last stage of CKD. However, there were indications that the travel time to the hospital for CKD treatment might be a contributing factor to the number of diagnosed CKD cases. This implies that the current structure for CKD management within the state might not be adequate.

Crossing the Barriers: An Analysis of Land Access Barriers to Geothermal Development and Potential Improvement Scenarios

Energy Technology Data Exchange (ETDEWEB)

Levine, Aaron L [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Young, Katherine R [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

2017-10-04

Developers have identified many non-technical barriers to geothermal power development, including access to land. Activities required for accessing land, such as environmental review and private and public leasing can take a considerable amount of time and can delay or prevent project development. This paper discusses the impacts to available geothermal resources and deployment caused by land access challenges, including tribal and cultural resources, environmentally sensitive areas, biological resources, land ownership, federal and state lease queues, and proximity to military installations. In this analysis, we identified challenges that have the potential to prevent development of identified and undiscovered hydrothermal geothermal resources. We found that an estimated 400 MW of identified geothermal resource potential and 4,000 MW of undiscovered geothermal resource potential were either unallowed for development or contained one or more significant barriers that could prevent development at the site. Potential improvement scenarios that could be employed to overcome these barriers include (1) providing continuous funding to the U.S. Forest Service (USFS) for processing geothermal leases and permit applications and (2) the creation of advanced environmental mitigation measures. The model results forecast that continuous funding to the USFS could result in deployment of an additional 80 MW of geothermal capacity by 2030 and 124 MW of geothermal capacity by 2050 when compared to the business-as-usual scenario. The creation of advanced environmental mitigation measures coupled with continuous funding to the USFS could result in deployment of an additional 97 MW of geothermal capacity by 2030 and 152 MW of geothermal capacity by 2050 when compared to the business-as-usual scenario. The small impact on potential deployment in these improvement scenarios suggests that these 4,400 MW have other barriers to development in addition to land access. In other words, simply

Mapping the geogenic radon potential: methodology and spatial analysis for central Hungary

International Nuclear Information System (INIS)

Szabó, Katalin Zsuzsanna; Jordan, Gyozo; Horváth, Ákos; Szabó, Csaba

2014-01-01

A detailed geogenic radon potential (GRP) mapping based on field soil gas radon and soil gas permeability measurements was carried out in this study. A conventional continuous variable approach was used in this study for GRP determination and to test its applicability to the selected area of Hungary. Spatial pattern of soil gas radon concentration, soil permeability and GRP and the relationship between geological formations and these parameters were studied by performing detailed spatial analysis. Exploratory data analysis revealed that higher soil gas radon activity concentration and GRP characterizes the mountains and hills than the plains. The highest values were found in the proluvial–deluvial sediments, rock debris on the downhill slopes eroded from hills. Among the Quaternary sediments, which characterize the study area, the fluvial sediment has the highest values, which are also located in the hilly areas. The lowest values were found in the plain areas covered by drift sand, fluvioeolic sand, fluvial sand and loess. As a conclusion, radon is related to the sediment cycle in the study area. A geogenic radon risk map was created, which assists human health risk assessment and risk reduction since it indicates the potential of the source of indoor radon. The map shows that low and medium geogenic radon potential characterizes the study area in central Hungary. High risk occurs only locally. The results reveal that Quaternary sediments are inhomogeneous from a radon point of view, fluvial sediment has medium GRP, whereas the other rock formations such as drift sand, fluioeolic sand, fluvial sand and loess, found in the study area, have low GRP. - Highlights: • First geogenic radon potential map in Hungary. • Low and medium GRP characterizes the study area (Middle Hungary). • Mainly quaternary sediments characterizes the study area. • Radon is related to the erosion and deposition of the sediment cycle

Population distribution, settlement patterns and accessibility across Africa in 2010.

Directory of Open Access Journals (Sweden)

Catherine Linard

Full Text Available The spatial distribution of populations and settlements across a country and their interconnectivity and accessibility from urban areas are important for delivering healthcare, distributing resources and economic development. However, existing spatially explicit population data across Africa are generally based on outdated, low resolution input demographic data, and provide insufficient detail to quantify rural settlement patterns and, thus, accurately measure population concentration and accessibility. Here we outline approaches to developing a new high resolution population distribution dataset for Africa and analyse rural accessibility to population centers. Contemporary population count data were combined with detailed satellite-derived settlement extents to map population distributions across Africa at a finer spatial resolution than ever before. Substantial heterogeneity in settlement patterns, population concentration and spatial accessibility to major population centres is exhibited across the continent. In Africa, 90% of the population is concentrated in less than 21% of the land surface and the average per-person travel time to settlements of more than 50,000 inhabitants is around 3.5 hours, with Central and East Africa displaying the longest average travel times. The analyses highlight large inequities in access, the isolation of many rural populations and the challenges that exist between countries and regions in providing access to services. The datasets presented are freely available as part of the AfriPop project, providing an evidence base for guiding strategic decisions.

The Effect of Spatial Interference Correlation and Jamming on Secrecy in Cellular Networks

KAUST Repository

Ali, Konpal S.

2017-06-02

Recent studies on secure wireless communication have shed light on a scenario where interference has a desirable impact on network performance. Particularly, assuming independent interference-power fluctuations at the eavesdropper and the receiver, opportunistic secure-information transfer can occur on the legitimate-link. However, interference is spatially correlated due to the common set of interfering sources, which may diminish the opportunistic-secure-spectrum-access (OSSA) probability. We study and quantify the effect of spatial interference correlation on OSSA in cellular-networks and investigate the potential of full-duplex jamming (FDJ) solutions. The results highlight the scenarios where FDJ improves OSSA performance.

The Effect of Spatial Interference Correlation and Jamming on Secrecy in Cellular Networks

KAUST Repository

Ali, Konpal S.; Elsawy, Hesham; Haenggi, Martin; Alouini, Mohamed-Slim

2017-01-01

Recent studies on secure wireless communication have shed light on a scenario where interference has a desirable impact on network performance. Particularly, assuming independent interference-power fluctuations at the eavesdropper and the receiver, opportunistic secure-information transfer can occur on the legitimate-link. However, interference is spatially correlated due to the common set of interfering sources, which may diminish the opportunistic-secure-spectrum-access (OSSA) probability. We study and quantify the effect of spatial interference correlation on OSSA in cellular-networks and investigate the potential of full-duplex jamming (FDJ) solutions. The results highlight the scenarios where FDJ improves OSSA performance.

Landscape-scale accessibility of livestock to tigers: implications of spatial grain for modeling predation risk to mitigate human-carnivore conflict.

Science.gov (United States)

Miller, Jennifer R B; Jhala, Yadvendradev V; Jena, Jyotirmay; Schmitz, Oswald J

2015-03-01

Innovative conservation tools are greatly needed to reduce livelihood losses and wildlife declines resulting from human-carnivore conflict. Spatial risk modeling is an emerging method for assessing the spatial patterns of predator-prey interactions, with applications for mitigating carnivore attacks on livestock. Large carnivores that ambush prey attack and kill over small areas, requiring models at fine spatial grains to predict livestock depredation hot spots. To detect the best resolution for predicting where carnivores access livestock, we examined the spatial attributes associated with livestock killed by tigers in Kanha Tiger Reserve, India, using risk models generated at 20, 100, and 200-m spatial grains. We analyzed land-use, human presence, and vegetation structure variables at 138 kill sites and 439 random sites to identify key landscape attributes where livestock were vulnerable to tigers. Land-use and human presence variables contributed strongly to predation risk models, with most variables showing high relative importance (≥0.85) at all spatial grains. The risk of a tiger killing livestock increased near dense forests and near the boundary of the park core zone where human presence is restricted. Risk was nonlinearly related to human infrastructure and open vegetation, with the greatest risk occurring 1.2 km from roads, 1.1 km from villages, and 8.0 km from scrubland. Kill sites were characterized by denser, patchier, and more complex vegetation with lower visibility than random sites. Risk maps revealed high-risk hot spots inside of the core zone boundary and in several patches in the human-dominated buffer zone. Validation against known kills revealed predictive accuracy for only the 20 m model, the resolution best representing the kill stage of hunting for large carnivores that ambush prey, like the tiger. Results demonstrate that risk models developed at fine spatial grains can offer accurate guidance on landscape attributes livestock should

Spatial analysis of elderly access to primary care services

Directory of Open Access Journals (Sweden)

Lozano-Gracia Nancy

2006-05-01

Full Text Available Abstract Background Admissions for Ambulatory Care Sensitive Conditions (ACSCs are considered preventable admissions, because they are unlikely to occur when good preventive health care is received. Thus, high rates of admissions for ACSCs among the elderly (persons aged 65 or above who qualify for Medicare health insurance are signals of poor preventive care utilization. The relevant geographic market to use in studying these admission rates is the primary care physician market. Our conceptual model assumes that local market conditions serving as interventions along the pathways to preventive care services utilization can impact ACSC admission rates. Results We examine the relationships between market-level supply and demand factors on market-level rates of ACSC admissions among the elderly residing in the U.S. in the late 1990s. Using 6,475 natural markets in the mainland U.S. defined by The Health Resources and Services Administration's Primary Care Service Area Project, spatial regression is used to estimate the model, controlling for disease severity using detailed information from Medicare claims files. Our evidence suggests that elderly living in impoverished rural areas or in sprawling suburban places are about equally more likely to be admitted for ACSCs. Greater availability of physicians does not seem to matter, but greater prevalence of non-physician clinicians and international medical graduates, relative to U.S. medical graduates, does seem to reduce ACSC admissions, especially in poor rural areas. Conclusion The relative importance of non-physician clinicians and international medical graduates in providing primary care to the elderly in geographic areas of greatest need can inform the ongoing debate regarding whether there is an impending shortage of physicians in the United States. These findings support other authors who claim that the existing supply of physicians is perhaps adequate, however the distribution of them across

Effects of nicotine on visuo-spatial selective attention as indexed by event-related potentials.

Science.gov (United States)

Meinke, A; Thiel, C M; Fink, G R

2006-08-11

Nicotine has been shown to specifically reduce reaction times to invalidly cued targets in spatial cueing paradigms. In two experiments, we used event-related potentials to test whether the facilitative effect of nicotine upon the detection of invalidly cued targets is due to a modulation of perceptual processing, as indexed by early attention-related event-related potential components. Furthermore, we assessed whether the effect of nicotine on such unattended stimuli depends upon the use of exogenous or endogenous cues. In both experiments, the electroencephalogram was recorded while non-smokers completed discrimination tasks in Posner-type paradigms after chewing a nicotine polacrilex gum (Nicorette 2 mg) in one session and a placebo gum in another session. Nicotine reduced reaction times to invalidly cued targets when cueing was endogenous. In contrast, no differential effect of nicotine on reaction times was observed when exogenous cues were used. Electrophysiologically, we found a similar attentional modulation of the P1 and N1 components under placebo and nicotine but a differential modulation of later event-related potential components at a frontocentral site. The lack of a drug-dependent modulation of P1 and N1 in the presence of a behavioral effect suggests that the effect of nicotine in endogenous visuo-spatial cueing tasks is not due to an alteration of perceptual processes. Rather, the differential modulation of frontocentral event-related potentials suggests that nicotine acts at later stages of target processing.

Lowering the barriers for accessing distributed geospatial big data to advance spatial data science: the PolarHub solution

Science.gov (United States)

Li, W.

2017-12-01

Data is the crux of science. The widespread availability of big data today is of particular importance for fostering new forms of geospatial innovation. This paper reports a state-of-the-art solution that addresses a key cyberinfrastructure research problem—providing ready access to big, distributed geospatial data resources on the Web. We first formulate this data-access problem and introduce its indispensable elements, including identifying the cyber-location, space and time coverage, theme, and quality of the dataset. We then propose strategies to tackle each data-access issue and make the data more discoverable and usable for geospatial data users and decision makers. Among these strategies is large-scale web crawling as a key technique to support automatic collection of online geospatial data that are highly distributed, intrinsically heterogeneous, and known to be dynamic. To better understand the content and scientific meanings of the data, methods including space-time filtering, ontology-based thematic classification, and service quality evaluation are incorporated. To serve a broad scientific user community, these techniques are integrated into an operational data crawling system, PolarHub, which is also an important cyberinfrastructure building block to support effective data discovery. A series of experiments were conducted to demonstrate the outstanding performance of the PolarHub system. We expect this work to contribute significantly in building the theoretical and methodological foundation for data-driven geography and the emerging spatial data science.

Measurement of the potential geographic accessibility from call to definitive care for patient with acute stroke.

Science.gov (United States)

Freyssenge, J; Renard, F; Schott, A M; Derex, L; Nighoghossian, N; Tazarourte, K; El Khoury, C

2018-01-12

The World Health Organization refers to stroke, the second most frequent cause of death in the world, in terms of pandemic. Present treatments are only effective within precise time windows. Only 10% of thrombolysis patients are eligible. Late assessment of the patient resulting from admission and lack of knowledge of the symptoms is the main explanation of lack of eligibility. The aim is the measurement of the time of access to treatment facilities for stroke victims, using ambulances (firemen ambulances or EMS ambulances) and private car. The method proposed analyses the potential geographic accessibility of stroke care infrastructure in different scenarios. The study allows better considering of the issues inherent to an area: difficult weather conditions, traffic congestion and failure to respect the distance limits of emergency transport. Depending on the scenario, access times vary considerably within the same commune. For example, between the first and the second scenario for cities in the north of Rhône county, there is a 10 min difference to the nearest Primary Stroke Center (PSC). For the first scenario, 90% of the population is 20 min away of the PSC and 96% for the second scenario. Likewise, depending on the modal vector (fire brigade or emergency medical service), overall accessibility from the emergency call to admission to a Comprehensive Stroke Center (CSC) can vary by as much as 15 min. The setting up of the various scenarios and modal comparison based on the calculation of overall accessibility makes this a new method for calculating potential access to care facilities. It is important to take into account the specific pathological features and the availability of care facilities for modelling. This method is innovative and recommendable for measuring accessibility in the field of health care. This study makes possible to highlight the patients' extension of care delays. Thus, this can impact the improvement of patient care and rethink the

Measuring access to primary health care: use of a GIS-based accessibility analysis

CSIR Research Space (South Africa)

Mokgalaka, H

2014-10-01

Full Text Available Spatial analytical tools and analyses are key enabling instruments which can be used to efficiently plan for public-spaces such as healthcare facilities in a metropolitan context. Improving the levels of access to public-spaces through various...

Spatial Knowledge Infrastructures - Creating Value for Policy Makers and Benefits the Community

Science.gov (United States)

Arnold, L. M.

2016-12-01

The spatial data infrastructure is arguably one of the most significant advancements in the spatial sector. It's been a game changer for governments, providing for the coordination and sharing of spatial data across organisations and the provision of accessible information to the broader community of users. Today however, end-users such as policy-makers require far more from these spatial data infrastructures. They want more than just data; they want the knowledge that can be extracted from data and they don't want to have to download, manipulate and process data in order to get the knowledge they seek. It's time for the spatial sector to reduce its focus on data in spatial data infrastructures and take a more proactive step in emphasising and delivering the knowledge value. Nowadays, decision-makers want to be able to query at will the data to meet their immediate need for knowledge. This is a new value proposal for the decision-making consumer and will require a shift in thinking. This paper presents a model for a Spatial Knowledge Infrastructure and underpinning methods that will realise a new real-time approach to delivering knowledge. The methods embrace the new capabilities afforded through the sematic web, domain and process ontologies and natural query language processing. Semantic Web technologies today have the potential to transform the spatial industry into more than just a distribution channel for data. The Semantic Web RDF (Resource Description Framework) enables meaning to be drawn from data automatically. While pushing data out to end-users will remain a central role for data producers, the power of the semantic web is that end-users have the ability to marshal a broad range of spatial resources via a query to extract knowledge from available data. This can be done without actually having to configure systems specifically for the end-user. All data producers need do is make data accessible in RDF and the spatial analytics does the rest.

Spatially explicit data: stewardship and ethical challenges in science.

Science.gov (United States)

Hartter, Joel; Ryan, Sadie J; Mackenzie, Catrina A; Parker, John N; Strasser, Carly A

2013-09-01

Scholarly communication is at an unprecedented turning point created in part by the increasing saliency of data stewardship and data sharing. Formal data management plans represent a new emphasis in research, enabling access to data at higher volumes and more quickly, and the potential for replication and augmentation of existing research. Data sharing has recently transformed the practice, scope, content, and applicability of research in several disciplines, in particular in relation to spatially specific data. This lends exciting potentiality, but the most effective ways in which to implement such changes, particularly for disciplines involving human subjects and other sensitive information, demand consideration. Data management plans, stewardship, and sharing, impart distinctive technical, sociological, and ethical challenges that remain to be adequately identified and remedied. Here, we consider these and propose potential solutions for their amelioration.

Assessing the development of Kenya National Spatial Data Infrastructure (KNSDI)

NARCIS (Netherlands)

Okuku, J.; Bregt, A.K.; Grus, L.

2014-01-01

Spatial data plays a vital role in developmental activities, whether natural resource management or socio-economic development. Spatial Data Infrastructures (SDIs) facilitate access, sharing and dissemination of spatial data necessary for complex decision-making processes of the future. Thus,

Spatial Structure of Cities and Distribution of Retail Sales - Analysis based on a Potential NEG Model (Japanese)

OpenAIRE

NAKAMURA Ryohei; TAKATSUKA Hajime

2009-01-01

This paper aims to estimate the retail sales turnover in cities based on a potential New Economic Geography (NEG) model, addressing how (the distribution of) sales turnover is explained by the spatial structure of cities. This also takes into account the population distribution, by treating the spatial distribution of population and retail sales turnover in the cities by district and street (cho and chome) data. The cities covered are prefectural cities excluding government ordinance cities l...

GIS-facilitated spatial narratives

DEFF Research Database (Denmark)

Møller-Jensen, Lasse; Jeppesen, Henrik; Kofie, Richard Y.

2008-01-01

on the thematically and narrative linking of a set of locations within an area. A spatial narrative that describes the - largely unsuccessful - history of Danish plantations on the Gold Coast (1788-1850) is implemented through the Google Earth client. This client is seen both as a type of media in itself for ‘home......-based' exploration of sites related to the narrative and as a tool that facilitates the design of spatial narratives before implementation within portable GIS devices. The Google Earth-based visualization of the spatial narrative is created by a Python script that outputs a web-accessible KML format file. The KML...

Assessing equitable access to urban green space: the role of engineered water infrastructure.

Science.gov (United States)

Wendel, Heather E Wright; Downs, Joni A; Mihelcic, James R

2011-08-15

Urban green space and water features provide numerous social, environmental, and economic benefits, yet disparities often exist in their distribution and accessibility. This study examines the link between issues of environmental justice and urban water management to evaluate potential improvements in green space and surface water access through the revitalization of existing engineered water infrastructures, namely stormwater ponds. First, relative access to green space and water features were compared for residents of Tampa, Florida, and an inner-city community of Tampa (East Tampa). Although disparities were not found in overall accessibility between Tampa and East Tampa, inequalities were apparent when quality, diversity, and size of green spaces were considered. East Tampa residents had significantly less access to larger, more desirable spaces and water features. Second, this research explored approaches for improving accessibility to green space and natural water using three integrated stormwater management development scenarios. These scenarios highlighted the ability of enhanced water infrastructures to increase access equality at a variety of spatial scales. Ultimately, the "greening" of gray urban water infrastructures is advocated as a way to address environmental justice issues while also reconnecting residents with issues of urban water management.

Gbm.auto: A software tool to simplify spatial modelling and Marine Protected Area planning.

Directory of Open Access Journals (Sweden)

Simon Dedman

Full Text Available Marine resource managers and scientists often advocate spatial approaches to manage data-poor species. Existing spatial prediction and management techniques are either insufficiently robust, struggle with sparse input data, or make suboptimal use of multiple explanatory variables. Boosted Regression Trees feature excellent performance and are well suited to modelling the distribution of data-limited species, but are extremely complicated and time-consuming to learn and use, hindering access for a wide potential user base and therefore limiting uptake and usage.We have built a software suite in R which integrates pre-existing functions with new tailor-made functions to automate the processing and predictive mapping of species abundance data: by automating and greatly simplifying Boosted Regression Tree spatial modelling, the gbm.auto R package suite makes this powerful statistical modelling technique more accessible to potential users in the ecological and modelling communities. The package and its documentation allow the user to generate maps of predicted abundance, visualise the representativeness of those abundance maps and to plot the relative influence of explanatory variables and their relationship to the response variables. Databases of the processed model objects and a report explaining all the steps taken within the model are also generated. The package includes a previously unavailable Decision Support Tool which combines estimated escapement biomass (the percentage of an exploited population which must be retained each year to conserve it with the predicted abundance maps to generate maps showing the location and size of habitat that should be protected to conserve the target stocks (candidate MPAs, based on stakeholder priorities, such as the minimisation of fishing effort displacement.By bridging the gap between advanced statistical methods for species distribution modelling and conservation science, management and policy, these

Making Spatial Statistics Service Accessible On Cloud Platform

OpenAIRE

Mu, X.; Wu, J.; Li, T; Zhong, Y.; Gao, X.

2014-01-01

Web service can bring together applications running on diverse platforms, users can access and share various data, information and models more effectively and conveniently from certain web service platform. Cloud computing emerges as a paradigm of Internet computing in which dynamical, scalable and often virtualized resources are provided as services. With the rampant growth of massive data and restriction of net, traditional web services platforms have some prominent problems existi...

Accessing High Spatial Resolution in Astronomy Using Interference Methods

Science.gov (United States)

Carbonel, Cyril; Grasset, Sébastien; Maysonnave, Jean

2018-01-01

In astronomy, methods such as direct imaging or interferometry-based techniques (Michelson stellar interferometry for example) are used for observations. A particular advantage of interferometry is that it permits greater spatial resolution compared to direct imaging with a single telescope, which is limited by diffraction owing to the aperture of…

Rainfall and Coconut Accession Explain the Composition and Abundance of the Community of Potential Auchenorrhyncha Phytoplasma Vectors in Brazil.

Science.gov (United States)

Silva, Flaviana G; Passos, Eliana M; Diniz, Leandro E C; Farias, Adriano P; Teodoro, Adenir V; Fernandes, Marcelo F; Dollet, Michel

2018-04-05

Coconut plantations are attacked by the lethal yellowing (LY), which is spreading rapidly with extremely destructive effects in several countries. The disease is caused by phytoplasmas that occur in the plant phloem and are transmitted by Haplaxius crudus (Van Duzee) (Auchenorrhyncha: Cixiidae). Owing to their phloem-sap feeding habit, other planthopper species possibly act as vectors. Here, we aimed at assessing the seasonal variation in the Auchenorrhyncha community in six dwarf coconut accessions. Also, we assessed the relative contribution of biotic (coconut accession) and abiotic (rainfall, temperature) in explaining Auchenorrhyncha composition and abundance. The Auchenorrhyncha community was monthly evaluated for 1 yr using yellow sticky traps. Among the most abundant species, Oecleus sp., Balclutha sp., Deltocephalinae sp.2, Deltocephalinae sp.3, Cenchreini sp., Omolicna nigripennis Caldwell (Derbidae), and Cedusa sp. are potential phytoplasma vectors. The composition of the Auchenorrhyncha community differed between dwarf coconut accessions and periods, namely, in March and April (transition from dry to rainy season) and August (transition from rainy to dry season). In these months, Oecleus sp. was predominantly found in the accessions Cameroon Red Dwarf, Malayan Red Dwarf, and Brazilian Red Dwarf Gramame, while Cenchreini sp. and Bolbonota sp. were dominant in the accessions Brazilian Yellow Dwarf Gramame, Malayan Yellow Dwarf, and Brazilian Green Dwarf Jequi. We conclude that dwarf coconut host several Auchenorrhyncha species potential phytoplasma vectors. Furthermore, coconut accessions could be exploited in breeding programs aiming at prevention of LY. However, rainfall followed by accessions mostly explained the composition and abundance of the Auchenorrhyncha community.

Aspects of the incorporation of spatial data into radioecological and restoration analysis

International Nuclear Information System (INIS)

Beresford, N.A.; Wright, S.M.; Howard, B.J.; Crout, N.M.J.; Arkhipov, A.; Voigt, G.

2002-01-01

In the last decade geographical information systems have been increasingly used to incorporate spatial data into radioecological analysis. This has allowed the development of models with spatially variable outputs. Two main approaches have been adopted in the development of spatial models. Empirical Tag based models applied across a range of spatial scales utilize underlying soil type maps and readily available radioecological data. Soil processes can also be modelled to allow the dynamic prediction of radionuclide soil to plant transfer. We discuss a dynamic semi-mechanistic radiocaesium soil to plant-transfer model, which utilizes readily available spatially variable soil parameters. Both approaches allow the identification of areas that may be vulnerable to radionuclide deposition, therefore enabling the targeting of intervention measures. Improved estimates of radionuclide fluxes and ingestion doses can be achieved by incorporating spatially varying inputs such as agricultural production and dietary habits in to these models. In this paper, aspects of such models, including data requirements, implementation and outputs are discussed and critically evaluated. The relative merits and disadvantages of the two spatial model approaches adopted within radioecology are discussed. We consider the usefulness of such models to aid decision-makers and access the requirements and potential of further application within radiological protection. (author)

Spatial Modeling of Industrial Windfall on Soils to Detect Woody Species with Potential for Bioremediation

Science.gov (United States)

S. Salazar; M. Mendoza; A. M. Tejeda

2006-01-01

A spatial model is presented to explain the concentration of heavy metals (Fe, Cu, Zn, Ni, Cr, Co and Pb), in the soils around the industrial complex near the Port of Veracruz, Mexico. Unexpected low concentration sites where then tested to detect woody plant species that may have the capability to hiperacumulate these contaminants, hence having a potential for...

Differences in Food Environment Perceptions and Spatial Attributes of Food Shopping between Residents of Low and High Food Access Areas

Science.gov (United States)

Sohi, Inderbir; Bell, Bethany A.; Liu, Jihong; Battersby, Sarah E.; Liese, Angela D.

2014-01-01

Objective To explore potential differences in food shopping behaviors and healthy food availability perceptions between residents living in areas with low and high food access. Design A cross-sectional telephone survey to assess food shopping behaviors and perceptions. Data from an eight-county food environment field census used to define the CDC (Centers for Disease Control and Prevention) healthier food retail tract and USDA ERS (United States Department of Agriculture Economic Research Service) food desert measure. Participants 968 residents in eight South Carolina counties. Main Outcome Measures Residents’ food shopping behaviors and healthy food availability perceptions. Analysis Linear and logistic regression. Results Compared to residents in high food access areas, residents in low food access areas traveled further to their primary food store (USDA ERS: 8.8 vs. 7.1 miles, p=0.03; CDC: 9.2 vs. 6.1 miles, pshopping miles per week; CDC 28.0 vs. 15.4 miles, pshopping access (p<0.001). Conclusions and Implications These findings lend support to ongoing community and policy interventions aimed at reducing food access disparities. PMID:24560861

Reasoning with spatial plans on the semantic web

NARCIS (Netherlands)

Hoekstra, R.; Winkels, R.; Hupkes, E.

2009-01-01

There are several reasons why citizens, businesses and civil servants need access to regulations. Unfortunately, traditional approaches that aim to provide this access fall short, especially in the area of spatial planning. Fairly straight-forward questions such as "where will I be able to perform

The Potential Use of Mobile Technology: Enhancing Accessibility and Communication in a Blended Learning Course

Science.gov (United States)

Mayisela, Tabisa

2013-01-01

Mobile technology is increasingly being used to support blended learning beyond computer centres. It has been considered as a potential solution to the problem of a shortage of computers for accessing online learning materials (courseware) in a blended learning course. The purpose of the study was to establish how the use of mobile technology…

Spatial and Temporal Variability of Potential Evaporation across North American Forests

Directory of Open Access Journals (Sweden)

Robbie A. Hember

2017-01-01

Full Text Available Given the widespread ecological implications that would accompany any significant change in evaporative demand of the atmosphere, this study investigated spatial and temporal variation in several accepted expressions of potential evaporation (PE. The study focussed on forest regions of North America, with 1 km-resolution spatial coverage and a monthly time step, from 1951–2014. We considered Penman’s model (EPen, the Priestley–Taylor model (EPT, ‘reference’ rates based on the Penman–Monteith model for grasslands (ERG, and reference rates for forests that are moderately coupled (ERFu and well coupled (ERFc to the atmosphere. To give context to the models, we also considered a statistical fit (EPanFit to measurements of pan evaporation (EPan. We documented how each model compared with EPan, differences in attribution of variance in PE to specific driving factors, mean spatial patterns, and time trends from 1951–2014. The models did not agree strongly on the sensitivity to underlying drivers, zonal variation of PE, or on the magnitude of trends from 1951–2014. Sensitivity to vapour pressure deficit (Da differed among models, being absent from EPT and strongest in ERFc. Time trends in reference rates derived from the Penman–Monteith equation were highly sensitive to how aerodynamic conductance was set. To the extent that EPanFit accurately reflects the sensitivity of PE to Da over land surfaces, future trends in PE based on the Priestley–Taylor model may underestimate increasing evaporative demand, while reference rates for forests, that assume strong canopy-atmosphere coupling in the Penman–Monteith model, may overestimate increasing evaporative demand. The resulting historical database, covering the spectrum of different models of PE applied in modern studies, can serve to further investigate biosphere-hydroclimate relationships across North America.

Developing a training module on Gender & spatial justice

NARCIS (Netherlands)

Tummers, L.C.

2015-01-01

Justice is more than a legal matter: it has spatial and environmental implications and is related to engineering. The concept of ‘spatial justice’ was introduced in 2010 in planning by Eduard Soja. It indicates the accessibility of urban resources such as education and healthcare. Under democratic

Spatially Resolved Artificial Chemistry

DEFF Research Database (Denmark)

Fellermann, Harold

2009-01-01

Although spatial structures can play a crucial role in chemical systems and can drastically alter the outcome of reactions, the traditional framework of artificial chemistry is a well-stirred tank reactor with no spatial representation in mind. Advanced method development in physical chemistry has...... made a class of models accessible to the realms of artificial chemistry that represent reacting molecules in a coarse-grained fashion in continuous space. This chapter introduces the mathematical models of Brownian dynamics (BD) and dissipative particle dynamics (DPD) for molecular motion and reaction...

Spatially Resolved Artificial Chemistry

DEFF Research Database (Denmark)

Fellermann, Harold

2009-01-01

made a class of models accessible to the realms of artificial chemistry that represent reacting molecules in a coarse-grained fashion in continuous space. This chapter introduces the mathematical models of Brownian dynamics (BD) and dissipative particle dynamics (DPD) for molecular motion and reaction......Although spatial structures can play a crucial role in chemical systems and can drastically alter the outcome of reactions, the traditional framework of artificial chemistry is a well-stirred tank reactor with no spatial representation in mind. Advanced method development in physical chemistry has...

Gardening in the desert: a spatial optimization approach to locating gardens in rapidly expanding urban environments.

Science.gov (United States)

Mack, Elizabeth A; Tong, Daoqin; Credit, Kevin

2017-10-16

Food access is a global issue, and for this reason, a wealth of studies are dedicated to understanding the location of food deserts and the benefits of urban gardens. However, few studies have linked these two strands of research together to analyze whether urban gardening activity may be a step forward in addressing issues of access for food desert residents. The Phoenix, Arizona metropolitan area is used as a case to demonstrate the utility of spatial optimization models for siting urban gardens near food deserts and on vacant land. The locations of urban gardens are derived from a list obtained from the Maricopa County Cooperative Extension office at the University of Arizona which were geo located and aggregated to Census tracts. Census tracts were then assigned to one of three categories: tracts that contain a garden, tracts that are immediately adjacent to a tract with a garden, and all other non-garden/non-adjacent census tracts. Analysis of variance is first used to ascertain whether there are statistical differences in the demographic, socio-economic, and land use profiles of these three categories of tracts. A maximal covering spatial optimization model is then used to identify potential locations for future gardening activities. A constraint of these models is that gardens be located on vacant land, which is a growing problem in rapidly urbanizing environments worldwide. The spatial analysis of garden locations reveals that they are centrally located in tracts with good food access. Thus, the current distribution of gardens does not provide an alternative food source to occupants of food deserts. The maximal covering spatial optimization model reveals that gardens could be sited in alternative locations to better serve food desert residents. In fact, 53 gardens may be located to cover 96.4% of all food deserts. This is an improvement over the current distribution of gardens where 68 active garden sites provide coverage to a scant 8.4% of food desert

Differences in food environment perceptions and spatial attributes of food shopping between residents of low and high food access areas.

Science.gov (United States)

Sohi, Inderbir; Bell, Bethany A; Liu, Jihong; Battersby, Sarah E; Liese, Angela D

2014-01-01

To explore potential differences in food shopping behaviors and healthy food availability perceptions between residents living in areas with low and high food access. A cross-sectional telephone survey to assess food shopping behaviors and perceptions. Data from an 8-county food environment field census used to define the Centers for Disease Control and Prevention (CDC) healthier food retail tract and US Department of Agriculture Economic Research Service food desert measure. A total of 968 residents in 8 South Carolina counties. Residents' food shopping behaviors and healthy food availability perceptions. Linear and logistic regression. Compared with residents in high food access areas, residents in low food access areas traveled farther to their primary food store (US Department of Agriculture Economic Research Service: 8.8 vs 7.1 miles, P = .03; CDC: 9.2 vs 6.1 miles, P shopping miles per week (CDC: 28.0 vs 15.4 miles; P shopping access (P Behavior. Published by Elsevier Inc. All rights reserved.

Accessibility, location, and employment center growth.

Science.gov (United States)

2015-03-01

The purpose of this research is to examine the relationship between accessibility and the : growth of employment centers in order to improve our understanding of how transportation : investments influence the spatial organization of metropolitan area...

World potential of renewable energies actually accessible in the nineties and environmental impacts analysis

International Nuclear Information System (INIS)

Dessus, B.; Devin, B.; Pharabod, F.

1992-01-01

The role that renewable energies could play in the world's regional and global energy balances gives rise to varied and often quite different evaluations including almost unbounded ones. Reliable information is still available on the different technologies and their economic costs. But, as the commercial development of these renewables is generally very weak, the arguments for postponing their real possible world and regional impact are frequently confused with short term market type considerations. To overcome that difficulty it is proposed to achieve a comprehensive analysis, region by region, of the actually accessible renewable energies at a given horizon. Then we adopt a methodology as the one employed to derive proven renewable energy reserves from energy renewable resources in which resources are defined by quantitative information on physical potential, when reserves take into account technical and economical accessibility

Interactive Installations for Spatial Access to Artistic Sketchbooks

DEFF Research Database (Denmark)

Christiansen, Henning; Laursen, Bjørn

2017-01-01

A book is a book – or is it? With present-day, aordable technology, we can scale a book to become a spatial object, or even a space in itself, of almost arbitrary size. We describe our design of and experiences with a generic interactive installation, called Viskbook, that provides a convincing...... illusion of oversize books, allowing the spectator to turn over the pages using natural and intuitive gestures. It provides a new media for exhibiting books in museums and elsewhere. It can be used for vulnerable and irreplaceable unique books, that otherwise would remain in the safe-box, and for books...

Single-trial detection of visual evoked potentials by common spatial patterns and wavelet filtering for brain-computer interface.

Science.gov (United States)

Tu, Yiheng; Huang, Gan; Hung, Yeung Sam; Hu, Li; Hu, Yong; Zhang, Zhiguo

2013-01-01

Event-related potentials (ERPs) are widely used in brain-computer interface (BCI) systems as input signals conveying a subject's intention. A fast and reliable single-trial ERP detection method can be used to develop a BCI system with both high speed and high accuracy. However, most of single-trial ERP detection methods are developed for offline EEG analysis and thus have a high computational complexity and need manual operations. Therefore, they are not applicable to practical BCI systems, which require a low-complexity and automatic ERP detection method. This work presents a joint spatial-time-frequency filter that combines common spatial patterns (CSP) and wavelet filtering (WF) for improving the signal-to-noise (SNR) of visual evoked potentials (VEP), which can lead to a single-trial ERP-based BCI.

Preliminary access routes and cost study analyses for seven potentially acceptable salt sites: Final report, October 1984

International Nuclear Information System (INIS)

1987-02-01

This report analyzes highway and railroad access to seven potentially acceptable salt repository sites: Richton Dome and Cypress Creek Dome in Mississippi, Vacherie Dome in Louisiana, Swisher County and Deaf Smith County in Texas, and Davis Canyon and Lavender Canyon in utah. The objectives of the study were to investigate the routing of reasonable access corridors to the sites, describe major characteristics of each route, and estimate the costs for constructing or upgrading highways and railroads. The routes used in the analysis are not necessarily recommended or preferred over other routes, nor do they represent an implied final selection. Detailed engineering studies must be performed for the Davis Canyon and Lavender Canyon highway access before the analyzed routes can be considered to be viable. 20 refs., 7 figs., 3 tabs

Potentials and limitations of spatial and demographic development in Kosovo-Metohija lignite basin

Directory of Open Access Journals (Sweden)

Spasić Nenad

2009-01-01

Full Text Available The initial research carried out for the purpose of elaborating the Spatial Plan for Kosovo-Metohija Lignite Basin indicated the need to address numerous conflicts and opposing interests in the area concerned. This required the Plan to focus on harmonizing the economic, social and spatial aspects of developing a mining-energy-industrial system (hereinafter MEIS and its surroundings, devising the new ways for the protection of local population interests and use of novel approaches in dealing with the environmental consequences of lignite exploitation and processing. The area wherein Kosovo-Metohija lignite deposits are found is replete with diverse conflicting interests, including insufficient and uneven development, extremely large overall and especially agrarian population density (among the highest in Europe, unemployment and a sizable portion of the grey economy, low level and quality of services of public interest, ethnic conflicts and polarization, etc. The environmental effects of MEIS activities in a situation of this kind were revealed by the early stages of research in all segments of economic, social and spatial development, along with a high degree of environmental degradation. The main conflict in the Plan area is the one between mining and agriculture, i.e. open pit lignite mining and high-fertility soil covering lignite deposits. The conflict is additionally aggravated by the remarkable density of agricultural population on this territory and high selling prices of the land. Therefore, a substantial part of the Plan’s propositions was related to the conditions of settlement and infrastructure relocation, population resettlement and measures to relieve the tensions and prevent the outbreak of potential conflicts in implementing the Plan. The Spatial Plan is conceived as a complex and comprehensive document defining the framework, basic principles, starting points and measures tackling the numerous development conflicts, spatial

Unidades habitacionais hoteleiras na Ilha de Santa Catarina: um estudo sobre acessibilidade espacial Habitational units in hotels of the Island of Santa Catarina: a study about Spatial accessibility

Directory of Open Access Journals (Sweden)

Vera Helena Moro Bins Ely

2009-01-01

Full Text Available Este artigo trata da avaliação das condições de acessibilidade espacial em unidades habitacionais (UHs, ditas acessíveis, de hotéis residenciais na ilha de Santa Catarina. Para tanto, visitas exploratórias permitiram o levantamento arquitetônico das UHs escolhidas e a análise de sua adequação aos parâmetros técnicos estabelecidos pela NBR 9050/2004. Entrevistas com diferentes usuários complementam o estudo na medida em que apontam as reais dificuldades enfrentadas por eles, devido às inadequadas soluções de acessibilidade presentes nos ambientes da rede hoteleira. Os métodos utilizados permitiram classificar os problemas de acessibilidade espacial segundo quatro componentes - orientação espacial, deslocamento, uso e comunicação - e relacioná-los às deficiências e habilidades dos diversos usuários. Encontrou-se maior prevalência de problemas ligados ao uso de mobiliários e equipamentos, os quais afetam a realização de atividades com conforto e independência. Verifica-se, também, que a NBR 9050/2004 ainda direciona seus parâmetros técnicos para atender principalmente deficientes físico-motores.This paper deals with the evaluation of the conditions of spatial accessibility in habitation units (UHs considered accessible in residential hotels on the Island of Santa Catarina. For this purpose, exploratory visits allowed an architectonic survey of the chosen UHs and an analysis of their adjustment to the technical parameters established by NBR 9050/2004. Interviews with different users completed the study which highlighted the real difficulties faced by them due to inadequate solutions of accessibility present in the hotel network environments. The methods facilitated a classification of the problems of spatial accessibility according to four components - spatial orientation, displacement, use and communication - and related them to the abilities and disabilities of the various users. A higher prevalence of problems

Potential for tree rings to reveal spatial patterns of past drought variability across western Australia

Science.gov (United States)

O'Donnell, Alison J.; Cook, Edward R.; Palmer, Jonathan G.; Turney, Chris S. M.; Grierson, Pauline F.

2018-02-01

Proxy records have provided major insights into the variability of past climates over long timescales. However, for much of the Southern Hemisphere, the ability to identify spatial patterns of past climatic variability is constrained by the sparse distribution of proxy records. This is particularly true for mainland Australia, where relatively few proxy records are located. Here, we (1) assess the potential to use existing proxy records in the Australasian region—starting with the only two multi-century tree-ring proxies from mainland Australia—to reveal spatial patterns of past hydroclimatic variability across the western third of the continent, and (2) identify strategic locations to target for the development of new proxy records. We show that the two existing tree-ring records allow robust reconstructions of past hydroclimatic variability over spatially broad areas (i.e. > 3° × 3°) in inland north- and south-western Australia. Our results reveal synchronous periods of drought and wet conditions between the inland northern and southern regions of western Australia as well as a generally anti-phase relationship with hydroclimate in eastern Australia over the last two centuries. The inclusion of 174 tree-ring proxy records from Tasmania, New Zealand and Indonesia and a coral record from Queensland did not improve the reconstruction potential over western Australia. However, our findings suggest that the addition of relatively few new proxy records from key locations in western Australia that currently have low reconstruction skill will enable the development of a comprehensive drought atlas for the region, and provide a critical link to the drought atlases of monsoonal Asia and eastern Australia and New Zealand.

Perceived Accessibility of Public Transport as a Potential Indicator of Social Inclusion

Directory of Open Access Journals (Sweden)

Katrin Lättman

2016-06-01

Full Text Available Perceived accessibility has been acknowledged as an important aspect of transport policy since the 70s. Nevertheless, very few empirical studies have been conducted in this field. When aiming to improve social inclusion, by making sustainable transport modes accessible to all, it is important to understand the factors driving perceived accessibility. Unlike conventional accessibility measures, perceived accessibility focuses on the perceived possibilities and ease of engaging in preferred activities using different transport modes. We define perceived accessibility in terms of how easy it is to live a satisfactory life with the help of the transport system, which is not necessarily the same thing as the objective standard of the system. According to previous research, perceived accessibility varies with the subjectively-rated quality of the mode of transport. Thus, improvements in quality (e.g. trip planning, comfort, or safety increase the perceived accessibility and make life easier to live using the chosen mode of transport. This study (n=750 focuses on the perceived accessibility of public transport, captured using the Perceived Accessibility Scale PAC (Lättman, Olsson, & Friman, 2015. More specifically, this study aims to determine how level of quality affects the perceived accessibility in public transport. A Conditional Process Model shows that, in addition to quality, feeling safe and frequency of travel are important predictors of perceived accessibility. Furthermore, elderly and those in their thirties report a lower level of perceived accessibility to their day-to-day activities using public transport. The basic premise of this study is that subjective experiences may be as important as objective indicators when planning and designing for socially inclusive transport systems.

Spatial response surface modelling in the presence of data paucity for the evaluation of potential human health risk due to the contamination of potable water resources.

Science.gov (United States)

Liu, Shen; McGree, James; Hayes, John F; Goonetilleke, Ashantha

2016-10-01

Potential human health risk from waterborne diseases arising from unsatisfactory performance of on-site wastewater treatment systems is driven by landscape factors such as topography, soil characteristics, depth to water table, drainage characteristics and the presence of surface water bodies. These factors are present as random variables which are spatially distributed across a region. A methodological framework is presented that can be applied to model and evaluate the influence of various factors on waterborne disease potential. This framework is informed by spatial data and expert knowledge. For prediction at unsampled sites, interpolation methods were used to derive a spatially smoothed surface of disease potential which takes into account the uncertainty due to spatial variation at any pre-determined level of significance. This surface was constructed by accounting for the influence of multiple variables which appear to contribute to disease potential. The framework developed in this work strengthens the understanding of the characteristics of disease potential and provides predictions of this potential across a region. The study outcomes presented constitutes an innovative approach to environmental monitoring and management in the face of data paucity. Copyright © 2016 Elsevier B.V. All rights reserved.

Access to emergency hospital care provided by the public sector in sub-Saharan Africa in 2015: a geocoded inventory and spatial analysis.

Science.gov (United States)

Ouma, Paul O; Maina, Joseph; Thuranira, Pamela N; Macharia, Peter M; Alegana, Victor A; English, Mike; Okiro, Emelda A; Snow, Robert W

2018-03-01

Timely access to emergency care can substantially reduce mortality. International benchmarks for access to emergency hospital care have been established to guide ambitions for universal health care by 2030. However, no Pan-African database of where hospitals are located exists; therefore, we aimed to complete a geocoded inventory of hospital services in Africa in relation to how populations might access these services in 2015, with focus on women of child bearing age. We assembled a geocoded inventory of public hospitals across 48 countries and islands of sub-Saharan Africa, including Zanzibar, using data from various sources. We only included public hospitals with emergency services that were managed by governments at national or local levels and faith-based or non-governmental organisations. For hospital listings without geographical coordinates, we geocoded each facility using Microsoft Encarta (version 2009), Google Earth (version 7.3), Geonames, Fallingrain, OpenStreetMap, and other national digital gazetteers. We obtained estimates for total population and women of child bearing age (15-49 years) at a 1 km 2 spatial resolution from the WorldPop database for 2015. Additionally, we assembled road network data from Google Map Maker Project and OpenStreetMap using ArcMap (version 10.5). We then combined the road network and the population locations to form a travel impedance surface. Subsequently, we formulated a cost distance algorithm based on the location of public hospitals and the travel impedance surface in AccessMod (version 5) to compute the proportion of populations living within a combined walking and motorised travel time of 2 h to emergency hospital services. We consulted 100 databases from 48 sub-Saharan countries and islands, including Zanzibar, and identified 4908 public hospitals. 2701 hospitals had either full or partial information about their geographical coordinates. We estimated that 287 282 013 (29·0%) people and 64 495 526 (28·2

Perceived Accessibility of Public Transport as a Potential Indicator of Social Inclusion

OpenAIRE

Lättman, Katrin; Friman, Margareta; Olsson, Lars E

2016-01-01

Perceived accessibility has been acknowledged as an important aspect of transport policy since the 70s. Nevertheless, very few empirical studies have been conducted in this field. When aiming to improve social inclusion, by making sustainable transport modes accessible to all, it is important to understand the factors driving perceived accessibility. Unlike conventional accessibility measures, perceived accessibility focuses on the perceived possibilities and ease of engaging in preferr...

Hierarchical modeling and analysis for spatial data

CERN Document Server

Banerjee, Sudipto; Gelfand, Alan E

2003-01-01

Among the many uses of hierarchical modeling, their application to the statistical analysis of spatial and spatio-temporal data from areas such as epidemiology And environmental science has proven particularly fruitful. Yet to date, the few books that address the subject have been either too narrowly focused on specific aspects of spatial analysis, or written at a level often inaccessible to those lacking a strong background in mathematical statistics.Hierarchical Modeling and Analysis for Spatial Data is the first accessible, self-contained treatment of hierarchical methods, modeling, and dat

HIPPOCAMPAL ADULT NEUROGENESIS: ITS REGULATION AND POTENTIAL ROLE IN SPATIAL LEARNING AND MEMORY

Science.gov (United States)

Lieberwirth, Claudia; Pan, Yongliang; Liu, Yan; Zhang, Zhibin; Wang, Zuoxin

2016-01-01

Adult neurogenesis, defined here as progenitor cell division generating functionally integrated neurons in the adult brain, occurs within the hippocampus of numerous mammalian species including humans. The present review details various endogenous (e.g., neurotransmitters) and environmental (e.g., physical exercise) factors that have been shown to influence hippocampal adult neurogenesis. In addition, the potential involvement of adult-generated neurons in naturally-occurring spatial learning behavior is discussed by summarizing the literature focusing on traditional animal models (e.g., rats and mice), non-traditional animal models (e.g., tree shrews), as well as natural populations (e.g., chickadees and Siberian chipmunk). PMID:27174001

On Novel Access and Scheduling Schemes for IoT Communications

Directory of Open Access Journals (Sweden)

Zheng Jiang

2016-01-01

Full Text Available The Internet of Things (IoT is expected to foster the development of 5G wireless networks and requires the efficient support for a large number of simultaneous short message communications. To address these challenges, some existing works utilize new waveform and multiuser superposition transmission schemes to improve the capacity of IoT communication. In this paper, we will investigate the spatial degree of freedom of IoT devices based on their distribution, then extend the multiuser shared access (MUSA which is one of the typical MUST schemes to spatial domain, and propose two novel schemes, that is, the preconfigured access scheme and the joint spatial and code domain scheduling scheme, to enhance IoT communication. The results indicate that the proposed schemes can reduce the collision rate dramatically during the IoT random access procedure and improve the performance of IoT communication obviously. Based on the simulation results, it is also shown that the proposed scheduling scheme can achieve the similar performance to the corresponding brute-force scheduling but with lower complexity.

Discovery of accessible locations using region-based geo-social data

KAUST Repository

Wang, Yan

2018-03-17

Geo-social data plays a significant role in location discovery and recommendation. In this light, we propose and study a novel problem of discovering accessible locations in spatial networks using region-based geo-social data. Given a set Q of query regions, the top-k accessible location discovery query (k ALDQ) finds k locations that have the highest spatial-density correlations to Q. Both the spatial distances between locations and regions and the POI (point of interest) density within the regions are taken into account. We believe that this type of k ALDQ query can bring significant benefit to many applications such as travel planning, facility allocation, and urban planning. Three challenges exist in k ALDQ: (1) how to model the spatial-density correlation practically, (2) how to prune the search space effectively, and (3) how to schedule the searches from multiple query regions. To tackle the challenges and process k ALDQ effectively and efficiently, we first define a series of spatial and density metrics to model the spatial-density correlation. Then we propose a novel three-phase solution with a pair of upper and lower bounds of the spatial-density correlation and a heuristic scheduling strategy to schedule multiple query regions. Finally, we conduct extensive experiments on real and synthetic spatial data to demonstrate the performance of the developed solutions.

Drivers potentially influencing host-bat fly interactions in anthropogenic neotropical landscapes at different spatial scales.

Science.gov (United States)

Hernández-Martínez, Jacqueline; Morales-Malacara, Juan B; Alvarez-Añorve, Mariana Yolotl; Amador-Hernández, Sergio; Oyama, Ken; Avila-Cabadilla, Luis Daniel

2018-05-21

The anthropogenic modification of natural landscapes, and the consequent changes in the environmental conditions and resources availability at multiple spatial scales can affect complex species interactions involving key-stone species such as bat-parasite interactions. In this study, we aimed to identify the drivers potentially influencing host-bat fly interactions at different spatial scales (at the host, vegetation stand and landscape level), in a tropical anthropogenic landscape. For this purpose, we mist-netted phyllostomid and moormopid bats and collected the bat flies (streblids) parasitizing them in 10 sites representing secondary and old growth forest. In general, the variation in fly communities largely mirrored the variation in bat communities as a result of the high level of specialization characterizing host-bat fly interaction networks. Nevertheless, we observed that: (1) bats roosting dynamics can shape bat-streblid interactions, modulating parasite prevalence and the intensity of infestation; (2) a degraded matrix could favor crowding and consequently the exchange of ectoparasites among bat species, lessening the level of specialization of the interaction networks and promoting novel interactions; and (3) bat-fly interaction can also be shaped by the dilution effect, as a decrease in bat diversity could be associated with a potential increase in the dissemination and prevalence of streblids.

Spatial updating grand canonical Monte Carlo algorithms for fluid simulation: generalization to continuous potentials and parallel implementation.

Science.gov (United States)

O'Keeffe, C J; Ren, Ruichao; Orkoulas, G

2007-11-21

Spatial updating grand canonical Monte Carlo algorithms are generalizations of random and sequential updating algorithms for lattice systems to continuum fluid models. The elementary steps, insertions or removals, are constructed by generating points in space either at random (random updating) or in a prescribed order (sequential updating). These algorithms have previously been developed only for systems of impenetrable spheres for which no particle overlap occurs. In this work, spatial updating grand canonical algorithms are generalized to continuous, soft-core potentials to account for overlapping configurations. Results on two- and three-dimensional Lennard-Jones fluids indicate that spatial updating grand canonical algorithms, both random and sequential, converge faster than standard grand canonical algorithms. Spatial algorithms based on sequential updating not only exhibit the fastest convergence but also are ideal for parallel implementation due to the absence of strict detailed balance and the nature of the updating that minimizes interprocessor communication. Parallel simulation results for three-dimensional Lennard-Jones fluids show a substantial reduction of simulation time for systems of moderate and large size. The efficiency improvement by parallel processing through domain decomposition is always in addition to the efficiency improvement by sequential updating.

Spatial chaos of trapped Bose-Einstein condensate in one-dimensional weak optical lattice potential

International Nuclear Information System (INIS)

Chong Guishu; Hai Wenhua; Xie Qiongtao

2004-01-01

The spatially chaotic attractor in an elongated cloud of Bose-Einstein condensed atoms perturbed by a weak optical lattice potential is studied. The analytical insolvability and numerical incomputability of the atomic number density are revealed by a perturbed solution that illustrates the unpredictability of the deterministic chaos. Although this could lead the nonphysical explosion and unboundedness to the numerical solution, the theoretical analysis offers a criterion to avoid them. Moreover, the velocity field is investigated that exhibits the superfluid property of the chaotic system

A description of spatial data infrastructure stakeholders in Ghana using the ICA model

CSIR Research Space (South Africa)

Owusu-Banahene, W

2013-11-01

Full Text Available Service, the Electoral Commission and the Ghana Meteorological Services Department. Some private companies, such as Rudan Engineering and GeoTech, were involved in NAFGIM as contractors or agents who worked for the Survey Department. As shown in Table...://www.gisdevelopment.net/proceedings/gisdeco/2004/keynote/ezipf.ht m [Accessed 8 April 2013]. Georgiadou, Y., Puri, S.K. and Sahay, S., (2005), Towards a Potential Research Agenda to Guide the Implementation of Spatial Data Infrastructures ʹ A Case Study from India. International Journal...

M2M massive wireless access

DEFF Research Database (Denmark)

Zanella, Andrea; Zorzi, Michele; Santos, André F.

2013-01-01

In order to make the Internet of Things a reality, ubiquitous coverage and low-complexity connectivity are required. Cellular networks are hence the most straightforward and realistic solution to enable a massive deployment of always connected Machines around the globe. Nevertheless, a paradigm...... shift in the conception and design of future cellular networks is called for. Massive access attempts, low-complexity and cheap machines, sporadic transmission and correlated signals are among the main properties of this new reality, whose main consequence is the disruption of the development...... Access Reservation, Coded Random Access and the exploitation of multiuser detection in random access. Additionally, we will show how the properties of machine originated signals, such as sparsity and spatial/time correlation can be exploited. The end goal of this paper is to provide motivation...

Spatial accessibility to basic public health services in South Sudan

Directory of Open Access Journals (Sweden)

Peter M. Macharia

2017-05-01

Full Text Available At independence in 2011, South Sudan’s health sector was almost non-existent. The first national health strategic plan aimed to achieve an integrated health facility network that would mean that 70% of the population were within 5 km of a health service provider. Publically available data on functioning and closed health facilities, population distribution, road networks, land use and elevation were used to compute the fraction of the population within 1 hour walking distance of the nearest public health facility offering curative services. This metric was summarised for each of the 78 counties in South Sudan and compared with simpler metrics of the proportion of the population within 5 km of a health facility. In 2016, it is estimated that there were 1747 public health facilities, out of which 294 were non-functional in part due to the on-going civil conflict. Access to a service provider was poor with only 25.7% of the population living within one-hour walking time to a facility and 28.6% of the population within 5 km. These metrics, when applied sub-nationally, identified the same high priority, most vulnerable counties. Simple metrics based upon population distribution and location of facilities might be as valuable as more complex models of health access, where attribute data on travel routes are imperfect or incomplete and sparse. Disparities exist in South Sudan among counties and those with the poorest health access should be targeted for priority expansion of clinical services.

A knowledge-based approach to estimating the magnitude and spatial patterns of potential threats to soil biodiversity.

Science.gov (United States)

Orgiazzi, Alberto; Panagos, Panos; Yigini, Yusuf; Dunbar, Martha B; Gardi, Ciro; Montanarella, Luca; Ballabio, Cristiano

2016-03-01

Because of the increasing pressures exerted on soil, below-ground life is under threat. Knowledge-based rankings of potential threats to different components of soil biodiversity were developed in order to assess the spatial distribution of threats on a European scale. A list of 13 potential threats to soil biodiversity was proposed to experts with different backgrounds in order to assess the potential for three major components of soil biodiversity: soil microorganisms, fauna, and biological functions. This approach allowed us to obtain knowledge-based rankings of threats. These classifications formed the basis for the development of indices through an additive aggregation model that, along with ad-hoc proxies for each pressure, allowed us to preliminarily assess the spatial patterns of potential threats. Intensive exploitation was identified as the highest pressure. In contrast, the use of genetically modified organisms in agriculture was considered as the threat with least potential. The potential impact of climate change showed the highest uncertainty. Fourteen out of the 27 considered countries have more than 40% of their soils with moderate-high to high potential risk for all three components of soil biodiversity. Arable soils are the most exposed to pressures. Soils within the boreal biogeographic region showed the lowest risk potential. The majority of soils at risk are outside the boundaries of protected areas. First maps of risks to three components of soil biodiversity based on the current scientific knowledge were developed. Despite the intrinsic limits of knowledge-based assessments, a remarkable potential risk to soil biodiversity was observed. Guidelines to preliminarily identify and circumscribe soils potentially at risk are provided. This approach may be used in future research to assess threat at both local and global scale and identify areas of possible risk and, subsequently, design appropriate strategies for monitoring and protection of soil

A spatially based field specific crop recordkeeping system prototype ...

African Journals Online (AJOL)

These spatial data were prepared using ArcGIS 9.3. A database was created in Microsoft Access 2007. The database contained information on crops, fertilizers and past management. The information was linked to the spatial data table and maintained in the database. An application was developed using Visual Basic 6 in ...

Spatial profile measurements of ion-confining potentials using novel position-sensitive ion-energy spectrometer arrays

International Nuclear Information System (INIS)

Yoshida, M.; Cho, T.; Hirata, M.; Ito, H.; Kohagura, J.; Yatsu, K.; Miyoshi, S.

2003-01-01

The first experimental demonstration of simultaneous measurements of temporally and spatially resolved ion-confining potentials phi c and end-loss-ion fluxes I ELA has been carried out during a single plasma discharge alone by the use of newly designed ion-energy-spectrometer arrays installed in both end regions of the GAMMA 10 tandem mirror. This position-sensitive ion-detector structure is proposed to obtain precise ion-energy spectra without any perturbations from simultaneously incident energetic electrons into the arrays. The relation between phi c and I ELA is physically interpreted in terms of Pastukhov's potential confinement theory. In particular, the importance of axisymmetric phi c formation is found for the plasma confinement

Evaluating accessibility to Bangkok Metro Systems using multi-dimensional criteria across user groups

Directory of Open Access Journals (Sweden)

Duangporn Prasertsubpakij

2012-07-01

Full Text Available Metro systems act as fast and efficient transport systems for many modern metropolises; however, enhancing higher usage of such systems often conflicts with providing suitable accessibility options. The traditional approach of metro accessibility studies seems to be an ineffective measure to gage sustainable access in which the equal rights of all users are taken into account. Bangkok Metropolitan Region (BMR transportation has increasingly relied on the role of two mass rapid transport systems publicly called “BTS Skytrain” and “MRT Subway”, due to limited availability of land and massive road congestion; however, access to such transit arguably treats some vulnerable groups, especially women, the elderly and disabled people unfairly. This study constructs a multi-dimensional assessment of accessibility considerations to scrutinize how user groups access metro services based on BMR empirical case. 600 individual passengers at various stations were asked to rate the questionnaire that simultaneously considers accessibility aspects of spatial, feeder connectivity, temporal, comfort/safety, psychosocial and other dimensions. It was interestingly found by user disaggregated accessibility model that the lower the accessibility perceptions—related uncomfortable and unsafe environment conditions, the greater the equitable access to services, as illustrated by MRT — Hua Lumphong and MRT — Petchaburi stations. The study suggests that, to balance the access priorities of groups on services, policy actions should emphasize acceptably safe access for individuals, cost efficient feeder services connecting the metro lines, socioeconomic influences and time allocation. Insightful discussions on integrated approach balancing different dimensions of accessibility and recommendations would contribute to accessibility-based knowledge and potential propensity to use the public transits towards transport sustainability.

Exploring the temporal dynamics of sustained and transient spatial attention using steady-state visual evoked potentials.

Science.gov (United States)

Zhang, Dan; Hong, Bo; Gao, Shangkai; Röder, Brigitte

2017-05-01

While the behavioral dynamics as well as the functional network of sustained and transient attention have extensively been studied, their underlying neural mechanisms have most often been investigated in separate experiments. In the present study, participants were instructed to perform an audio-visual spatial attention task. They were asked to attend to either the left or the right hemifield and to respond to deviant transient either auditory or visual stimuli. Steady-state visual evoked potentials (SSVEPs) elicited by two task irrelevant pattern reversing checkerboards flickering at 10 and 15 Hz in the left and the right hemifields, respectively, were used to continuously monitor the locus of spatial attention. The amplitude and phase of the SSVEPs were extracted for single trials and were separately analyzed. Sustained attention to one hemifield (spatial attention) as well as to the auditory modality (intermodal attention) increased the inter-trial phase locking of the SSVEP responses, whereas briefly presented visual and auditory stimuli decreased the single-trial SSVEP amplitude between 200 and 500 ms post-stimulus. This transient change of the single-trial amplitude was restricted to the SSVEPs elicited by the reversing checkerboard in the spatially attended hemifield and thus might reflect a transient re-orienting of attention towards the brief stimuli. Thus, the present results demonstrate independent, but interacting neural mechanisms of sustained and transient attentional orienting.

Essays on the Impacts of Geography and Institutions on Access to Energy and Public Infrastructure Services

Science.gov (United States)

Archibong, Belinda

While previous literature has emphasized the importance of energy and public infrastructure services for economic development, questions surrounding the implications of unequal spatial distribution in access to these resources remain, particularly in the developing country context. This dissertation provides evidence on the nature, origins and implications of this distribution uniting three strands of research from the development and political economy, regional science and energy economics fields. The dissertation unites three papers on the nature of spatial inequality of access to energy and infrastructure with further implications for conflict risk , the historical institutional and biogeographical determinants of current distribution of access to energy and public infrastructure services and the response of households to fuel price changes over time. Chapter 2 uses a novel survey dataset to provide evidence for spatial clustering of public infrastructure non-functionality at schools by geopolitical zone in Nigeria with further implications for armed conflict risk in the region. Chapter 3 investigates the drivers of the results in chapter 2, exploiting variation in the spatial distribution of precolonial institutions and geography in the region, to provide evidence for the long-term impacts of these factors on current heterogeneity of access to public services. Chapter 4 addresses the policy implications of energy access, providing the first multi-year evidence on firewood demand elasticities in India, using the spatial variation in prices for estimation.

Topology-selective jamming of fully-connected, code-division random-access networks

Science.gov (United States)

Polydoros, Andreas; Cheng, Unjeng

1990-01-01

The purpose is to introduce certain models of topology selective stochastic jamming and examine its impact on a class of fully-connected, spread-spectrum, slotted ALOHA-type random access networks. The theory covers dedicated as well as half-duplex units. The dominant role of the spatial duty factor is established, and connections with the dual concept of time selective jamming are discussed. The optimal choices of coding rate and link access parameters (from the users' side) and the jamming spatial fraction are numerically established for DS and FH spreading.

Laying Bare the Landscape: commercial archaeology and the potential of digital spatial data

Directory of Open Access Journals (Sweden)

Wendy Morrison

2014-08-01

Full Text Available This article summarises the methodology we have applied to an intensively investigated part of the Upper Thames Valley. We discuss the potential of digital spatially referenced data to help bridge the gaps between the various commercial units who work side by side in the landscape, as well as between the various planning authorities. This article will be of interest to anyone working with digital data or with diverse datasets to understand wider landscapes, as well as anyone working with various funders, developers, and consultancies to plan for the best use of such 'big data' to improve heritage management and archaeological enquiry.

A new two dimensional spectral/spatial multi-diagonal code for noncoherent optical code division multiple access (OCDMA) systems

Science.gov (United States)

Kadhim, Rasim Azeez; Fadhil, Hilal Adnan; Aljunid, S. A.; Razalli, Mohamad Shahrazel

2014-10-01

A new two dimensional codes family, namely two dimensional multi-diagonal (2D-MD) codes, is proposed for spectral/spatial non-coherent OCDMA systems based on the one dimensional MD code. Since the MD code has the property of zero cross correlation, the proposed 2D-MD code also has this property. So that, the multi-access interference (MAI) is fully eliminated and the phase induced intensity noise (PIIN) is suppressed with the proposed code. Code performance is analyzed in terms of bit error rate (BER) while considering the effect of shot noise, PIIN, and thermal noise. The performance of the proposed code is compared with the related MD, modified quadratic congruence (MQC), two dimensional perfect difference (2D-PD) and two dimensional diluted perfect difference (2D-DPD) codes. The analytical and the simulation results reveal that the proposed 2D-MD code outperforms the other codes. Moreover, a large number of simultaneous users can be accommodated at low BER and high data rate.

A spatial assessment of ecosystem services in Europe - Phase II

DEFF Research Database (Denmark)

Maes, Joachim; Hauck, Jennifer; Paracchini,, Maria Luisa

forests several times per year and they expressed their willingness to pay to continue doing so. The visitor statistics that were used in this study confirmed the usefulness of the ROS approach (Recreation Opportunity Spectrum) to identify areas in terms of their accessibility and potential to provide......, mapping and valuation. Linking the maps of ecosystem service supply to monetary valuation allowed an analysis of the expected impact of policy measures on benefits derived from ecosystem services. The recreation case, which Marianne participated in, presents evidence that millions of people visited...... recreation services. In addition, PRESS-2 presents a spatial analysis of city population density and green urban areas....

Identification of a potential toxic hot spot associated with AVS spatial and seasonal variation.

Science.gov (United States)

Campana, O; Rodríguez, A; Blasco, J

2009-04-01

In risk assessment of aquatic sediments, much attention is paid to the difference between acid-volatile sulfide (AVS) and simultaneously extracted metals (SEMs) as indicators of metal availability. Ten representative sampling sites were selected along the estuary of the Guadalete River. Surficial sediments were sampled in winter and summer to better understand SEM and AVS spatial and seasonal distributions and to establish priority risk areas. Total SEM concentration (SigmaSEM) ranged from 0.3 to 4.7 micromol g(-1). It was not significantly different between seasons, however, it showed a significant difference between sampling stations. AVS concentrations were much more variable, showing significant spatial and temporal variations. The values ranged from 0.8 to 22.4 micromol g(-1). The SEM/AVS ratio was found to be <1 at all except one station located near the mouth of the estuary. The results provided information on a potential pollution source near the mouth of the estuary, probably associated with vessel-related activities carried out in a local harbor area located near the station.

Mapping equality in access : the case of Bogota's sustainable transport initiatives

NARCIS (Netherlands)

Teunissen, Thijs; Sarmiento, Olga; Zuidgeest (Former Assistant Professor), Mark; Brussel, M.J.G.

2015-01-01

To enhance social equity, three important sustainable transportation initiatives have been introduced in Bogotá. Spatial information and GIS have been used to analyze levels of inequality in access to these initiatives. The results show that the TransMilenio BRT offers equal access for all

Web-based access, aggregation, and visualization of future climate projections with emphasis on agricultural assessments

Science.gov (United States)

Villoria, Nelson B.; Elliott, Joshua; Müller, Christoph; Shin, Jaewoo; Zhao, Lan; Song, Carol

2018-01-01

Access to climate and spatial datasets by non-specialists is restricted by technical barriers involving hardware, software and data formats. We discuss an open-source online tool that facilitates downloading the climate data from the global circulation models used by the Inter-Sectoral Impacts Model Intercomparison Project. The tool also offers temporal and spatial aggregation capabilities for incorporating future climate scenarios in applications where spatial aggregation is important. We hope that streamlined access to these data facilitates analysis of climate related issues while considering the uncertainties derived from future climate projections and temporal aggregation choices.

Spatial Supermarket Redlining and Neighborhood Vulnerability: A Case Study of Hartford, Connecticut.

Science.gov (United States)

Zhang, Mengyao; Debarchana, Ghosh

2016-02-01

The disinclination of chain supermarkets to locate or pull out existing stores from impoverished neighborhoods is termed as "supermarket redlining". This paper attempts to map and understand the spatial effects of potential supermarket redlining on food vulnerability in urban disadvantaged neighborhoods of Hartford, Connecticut. Using a combination of statistical and spatial analysis functions, we first, built a Supermarket Redlining Index (SuRI) from five indicators such as sales volume, employee count, accepts food coupons from federally assisted programs, and size and population density of the service area to rank supermarkets in the order of their importance. Second, to understand the effect of redlining, a Supermarket Redlining Impact Model (SuRIM) was built with eleven indicators describing both the socioeconomic and food access vulnerabilities. The interaction of these vulnerabilities would identify the final outcome: neighborhoods where the impact of supermarket redlining would be critical. Results mapped critical areas in the inner-city of Hartford where if a nearby supermarket closes or relocates to a suburb with limited mitigation efforts to gill the grocery gap, a large number of minority, poor, and disadvantaged residents will experience difficulties to access healthy food leading to food insecurity or perhaps a food desert. We also suggest mitigation efforts to reduce the impact of large supermarket closures.

Anticipating potential biodiversity conflicts for future biofuel crops in South Africa: incorporating spatial filters with species distribution models

CSIR Research Space (South Africa)

Blanchard, R

2014-04-01

Full Text Available @csir.co.za; 14 15 Keywords: Bioenergy crops, Land suitability, Biodiversity, Spatial analysis, MaxEnt, 16 Conflict, Agricultural land, Spatial filters 17 18 Primary research article 19 Page 1 of 48 GCB Bioenergy 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17... habitat transformation and provides 21 an objective means of mitigating potential conflict with existing land use and biodiversity. 22 23 Page 2 of 48GCB Bioenergy 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32...

Local consequences of national policies - a spatial analysis of preferences for forest access reduction

DEFF Research Database (Denmark)

Nielsen, Anne Sofie Elberg; Lundhede, Thomas; Jacobsen, Jette Bredahl

2016-01-01

Stated preference studies eliciting welfare economic consequence of national policies, are often not considering the spatial variation in supply and demand. This spatial variation may however cause large distributional heterogeneity of policy changes. In this study, we use a choice experiment to ...

a Novel Approach of Indexing and Retrieving Spatial Polygons for Efficient Spatial Region Queries

Science.gov (United States)

Zhao, J. H.; Wang, X. Z.; Wang, F. Y.; Shen, Z. H.; Zhou, Y. C.; Wang, Y. L.

2017-10-01

Spatial region queries are more and more widely used in web-based applications. Mechanisms to provide efficient query processing over geospatial data are essential. However, due to the massive geospatial data volume, heavy geometric computation, and high access concurrency, it is difficult to get response in real time. Spatial indexes are usually used in this situation. In this paper, based on k-d tree, we introduce a distributed KD-Tree (DKD-Tree) suitbable for polygon data, and a two-step query algorithm. The spatial index construction is recursive and iterative, and the query is an in memory process. Both the index and query methods can be processed in parallel, and are implemented based on HDFS, Spark and Redis. Experiments on a large volume of Remote Sensing images metadata have been carried out, and the advantages of our method are investigated by comparing with spatial region queries executed on PostgreSQL and PostGIS. Results show that our approach not only greatly improves the efficiency of spatial region query, but also has good scalability, Moreover, the two-step spatial range query algorithm can also save cluster resources to support a large number of concurrent queries. Therefore, this method is very useful when building large geographic information systems.

A NOVEL APPROACH OF INDEXING AND RETRIEVING SPATIAL POLYGONS FOR EFFICIENT SPATIAL REGION QUERIES

Directory of Open Access Journals (Sweden)

J. H. Zhao

2017-10-01

Full Text Available Spatial region queries are more and more widely used in web-based applications. Mechanisms to provide efficient query processing over geospatial data are essential. However, due to the massive geospatial data volume, heavy geometric computation, and high access concurrency, it is difficult to get response in real time. Spatial indexes are usually used in this situation. In this paper, based on k-d tree, we introduce a distributed KD-Tree (DKD-Tree suitbable for polygon data, and a two-step query algorithm. The spatial index construction is recursive and iterative, and the query is an in memory process. Both the index and query methods can be processed in parallel, and are implemented based on HDFS, Spark and Redis. Experiments on a large volume of Remote Sensing images metadata have been carried out, and the advantages of our method are investigated by comparing with spatial region queries executed on PostgreSQL and PostGIS. Results show that our approach not only greatly improves the efficiency of spatial region query, but also has good scalability, Moreover, the two-step spatial range query algorithm can also save cluster resources to support a large number of concurrent queries. Therefore, this method is very useful when building large geographic information systems.

Access to emergency hospital care provided by the public sector in sub-Saharan Africa in 2015: a geocoded inventory and spatial analysis

Directory of Open Access Journals (Sweden)

Paul O Ouma, MSc

2018-03-01

Full Text Available Summary: Background: Timely access to emergency care can substantially reduce mortality. International benchmarks for access to emergency hospital care have been established to guide ambitions for universal health care by 2030. However, no Pan-African database of where hospitals are located exists; therefore, we aimed to complete a geocoded inventory of hospital services in Africa in relation to how populations might access these services in 2015, with focus on women of child bearing age. Methods: We assembled a geocoded inventory of public hospitals across 48 countries and islands of sub-Saharan Africa, including Zanzibar, using data from various sources. We only included public hospitals with emergency services that were managed by governments at national or local levels and faith-based or non-governmental organisations. For hospital listings without geographical coordinates, we geocoded each facility using Microsoft Encarta (version 2009, Google Earth (version 7.3, Geonames, Fallingrain, OpenStreetMap, and other national digital gazetteers. We obtained estimates for total population and women of child bearing age (15–49 years at a 1 km2 spatial resolution from the WorldPop database for 2015. Additionally, we assembled road network data from Google Map Maker Project and OpenStreetMap using ArcMap (version 10.5. We then combined the road network and the population locations to form a travel impedance surface. Subsequently, we formulated a cost distance algorithm based on the location of public hospitals and the travel impedance surface in AccessMod (version 5 to compute the proportion of populations living within a combined walking and motorised travel time of 2 h to emergency hospital services. Findings: We consulted 100 databases from 48 sub-Saharan countries and islands, including Zanzibar, and identified 4908 public hospitals. 2701 hospitals had either full or partial information about their geographical coordinates. We estimated that 287

A study of verbal and spatial information processing using event-related potentials and positron emission tomography

International Nuclear Information System (INIS)

Ninomiya, Hideaki; Ichimiya, Atsushi; Chen, Chung-Ho; Onitsuka, Toshiaki; Kuwabara, Yasuo; Otsuka, Makoto; Ichiya, Yuichi

1997-01-01

The activated cerebral regions and the timing of information processing in the hemispheres was investigated using event-related potentials (ERP) and regional cerebral blood flow (rCBF) as the neurophysiological indicators. Seven men and one woman (age 19-27 years) were asked to categorize two-syllable Japanese nouns (verbal condition) and to judge the difference between pairs of rectangles (spatial condition), both tests presented on a monochrome display. In the electroencephalogram (EEG) session, EEG were recorded from 16 electrode sites, with linked earlobe electrodes as reference. In the positron emission tomography (PET) session, rCBF were measured by the 15 O-labeled H 2 O bolus injection method. Regions of interest were the frontal, temporal, parietal, occipital and central lobes, and the entire cerebral hemispheres. When the subtracted voltages of the ERP in homologous scalp sites were compared for the verbal and spatial conditions, the significant differences were at F7·F8 and T5·T6 (the 10-20 system). The latencies of the differences at T5·T6 were around 200, 250 and 320 ms. A significant difference in rCBF between the verbal and spatial conditions was found only in the temporal region. It was concluded that early processing of information, that is, registration and simple recognition, may be performed mainly in the left temporal lobe for verbal information and in the right for spatial information. (author)

[Spatial-temporal variations of spring maize potential yields in a changing climate in Northeast China.

Science.gov (United States)

Liu, Zhi Juan; Yang, Xiao Guang; Lyu, Shuo; Wang, Jing; Lin, Xiao Mao

2018-01-01

Based on meteorological data, agro-meteorological observations, and agricultural statistical data in Northeast China (NEC), by using the validated Agricultural Production System sIMulator (APSIM-maize), the potential, attainable, potential farmers' and actual farmers' yields of spring maize during the period 1961 to 2015 were analyzed, and the effects of climate variation on maize potential yield in NEC were quantified. Results indicated that the potential yield of spring maize was 12.2 t·hm -2 during the period 1961 to 2015, with those in northeast being lower than southwest within the study region. The attainable yield of spring maize was 11.3 t·hm -2 , and showed a similar spatial distribution with potential yield. Under the current farmers' management practices, mean simulated potential and actual farmers' yields were 6.5 and 4.5 t·hm -2 , respectively. Assuming there were no changes in cultivars and management practices in NEC, the mean potential, attainable, and potential farmers' yields of spring maize would decrease by 0.34, 0.25 and 0.10 t·hm -2 per decade in NEC. However, the actual farmers' yields increased with the value of 1.27 t·hm -2 per decade averaged over NEC. Due to climate variation, year-to-year variations of spring maize potential, attainable, and potential farmers' yields were significant, ranging from 10.0 to 14.4, 9.8 to 13.3, 4.4 to 8.5 t·hm -2 , respectively.

Unimodal and crossmodal gradients of spatial attention

DEFF Research Database (Denmark)

Föcker, J.; Hötting, K.; Gondan, Matthias

2010-01-01

Behavioral and event-related potential (ERP) studies have shown that spatial attention is gradually distributed around the center of the attentional focus. The present study compared uni- and crossmodal gradients of spatial attention to investigate whether the orienting of auditory and visual...... spatial attention is based on modality specific or supramodal representations of space. Auditory and visual stimuli were presented from five speaker locations positioned in the right hemifield. Participants had to attend to the innermost or outmost right position in order to detect either visual...... or auditory deviant stimuli. Detection rates and event-related potentials (ERPs) indicated that spatial attention is distributed as a gradient. Unimodal spatial ERP gradients correlated with the spatial resolution of the modality. Crossmodal spatial gradients were always broader than the corresponding...

Decentralization and Distribution Primary Education Access in Indonesia 2014

OpenAIRE

Benita, Novinaz

2016-01-01

This paper examines decentralisation and distribution of access to primary school in Indonesia. Data come from Indonesia National Socio Economic Survey 2014, and statistic reports from Ministry of education, Ministry Of Finance, and General Election Commision. Descriptive statistic is used to describe spatial distribution of decentralization in primary education system and distribution of primary education access. The results show there are districts disparities in decentralization of primary...

A Poisson-lognormal conditional-autoregressive model for multivariate spatial analysis of pedestrian crash counts across neighborhoods.

Science.gov (United States)

Wang, Yiyi; Kockelman, Kara M

2013-11-01

This work examines the relationship between 3-year pedestrian crash counts across Census tracts in Austin, Texas, and various land use, network, and demographic attributes, such as land use balance, residents' access to commercial land uses, sidewalk density, lane-mile densities (by roadway class), and population and employment densities (by type). The model specification allows for region-specific heterogeneity, correlation across response types, and spatial autocorrelation via a Poisson-based multivariate conditional auto-regressive (CAR) framework and is estimated using Bayesian Markov chain Monte Carlo methods. Least-squares regression estimates of walk-miles traveled per zone serve as the exposure measure. Here, the Poisson-lognormal multivariate CAR model outperforms an aspatial Poisson-lognormal multivariate model and a spatial model (without cross-severity correlation), both in terms of fit and inference. Positive spatial autocorrelation emerges across neighborhoods, as expected (due to latent heterogeneity or missing variables that trend in space, resulting in spatial clustering of crash counts). In comparison, the positive aspatial, bivariate cross correlation of severe (fatal or incapacitating) and non-severe crash rates reflects latent covariates that have impacts across severity levels but are more local in nature (such as lighting conditions and local sight obstructions), along with spatially lagged cross correlation. Results also suggest greater mixing of residences and commercial land uses is associated with higher pedestrian crash risk across different severity levels, ceteris paribus, presumably since such access produces more potential conflicts between pedestrian and vehicle movements. Interestingly, network densities show variable effects, and sidewalk provision is associated with lower severe-crash rates. Copyright © 2013 Elsevier Ltd. All rights reserved.

Spatial and Decadal Variations in Potential Evapotranspiration of China Based on Reanalysis Datasets during 1982–2010

Directory of Open Access Journals (Sweden)

Yunjun Yao

2014-10-01

Full Text Available Potential evapotranspiration (PET is an important indicator of atmospheric evaporation demand and has been widely used to characterize hydrological change. However, sparse observations of pan evaporation (EP prohibit the accurate characterization of the spatial and temporal patterns of PET over large spatial scales. In this study, we have estimated PET of China using the Penman-Monteith (PM method driven by gridded reanalysis datasets to analyze the spatial and decadal variations of PET in China during 1982–2010. The results show that the estimated PET has decreased on average by 3.3 mm per year (p < 0.05 over China during 1982–1993, while PET began to increase since 1994 by 3.4 mm per year (p < 0.05. The spatial pattern of the linear trend in PET of China illustrates that a widely significant increasing trend in PET appears during 1982–2010 in Northwest China, Central China, Northeast China and South China while there are no obvious variations of PET in other regions. Our findings illustrate that incident solar radiation (Rs is the largest contributor to the variation of PET in China, followed by vapor pressure deficit (VPD, air temperature (Tair and wind speed (WS. However, WS is the primary factor controlling inter-annual variation of PET over Northwest China.

Spatial Analysis of Geothermal Resource Potential in New York and Pennsylvania: A Stratified Kriging Approach

Science.gov (United States)

Smith, J. D.; Whealton, C. A.; Stedinger, J. R.

2014-12-01

Resource assessments for low-grade geothermal applications employ available well temperature measurements to determine if the resource potential is sufficient for supporting district heating opportunities. This study used a compilation of bottomhole temperature (BHT) data from recent unconventional shale oil and gas wells, along with legacy oil, gas, and storage wells, in Pennsylvania (PA) and New York (NY). Our study's goal was to predict the geothermal resource potential and associated uncertainty for the NY-PA region using kriging interpolation. The dataset was scanned for outliers, and some observations were removed. Because these wells were drilled for reasons other than geothermal resource assessment, their spatial density varied widely. An exploratory spatial statistical analysis revealed differences in the spatial structure of the geothermal gradient data (the kriging semi-variogram and its nugget variance, shape, sill, and the degree of anisotropy). As a result, a stratified kriging procedure was adopted to better capture the statistical structure of the data, to generate an interpolated surface, and to quantify the uncertainty of the computed surface. The area was stratified reflecting different physiographic provinces in NY and PA that have geologic properties likely related to variations in the value of the geothermal gradient. The kriging prediction and the variance-of-prediction were determined for each province by the generation of a semi-variogram using only the wells that were located within that province. A leave-one-out cross validation (LOOCV) was conducted as a diagnostic tool. The results of stratified kriging were compared to kriging using the whole region to determine the impact of stratification. The two approaches provided similar predictions of the geothermal gradient. However, the variance-of-prediction was different. The stratified approach is recommended because it gave a more appropriate site-specific characterization of uncertainty

The last mile in the Brazilian Amazon – A potential pathway for universal electricity access

International Nuclear Information System (INIS)

Gómez, Maria F.; Silveira, Semida

2015-01-01

The Brazilian rural electrification initiative Luz Para Todos – LPT (Light for All) has attracted attention internationally due to its ambitious targets and significant achievements in the last decade. The initiative has proved effective in its first phase, which has been developed through the extension of the grid. Yet, there are still important challenges to provide the service to inhabitants of remote areas in the Brazilian Amazon. We identify these challenges within institutional, technology, and funding structures operating within LPT. In line with these challenges, we propose a pathway to facilitate the achievement of universal electricity access in remote areas of the region. The proposed pathway is based on three key leverage points: (i) rules guiding the relationship among new agents and communities; (ii) the implementation of small-scale power generation technologies based on local resources; and (iii) optimized subsidies. It has the potential to allow (i) a better dimensioning of off-grid solutions considering local resources and realities, (ii) the creation of adapted institutions capable of implementing and operating the required systems and, (iii) an effective operation of off-grid solutions. -- Highlights: •There are important challenges to provide universal electricity access in the Amazon. •We propose a pathway to facilitate universal electricity access in remote areas of the Amazon. •The pathway allows a transition to a more knowledge-driven and participatory system

Dissociable Decoding of Spatial Attention and Working Memory from EEG Oscillations and Sustained Potentials.

Science.gov (United States)

Bae, Gi-Yeul; Luck, Steven J

2018-01-10

In human scalp EEG recordings, both sustained potentials and alpha-band oscillations are present during the delay period of working memory tasks and may therefore reflect the representation of information in working memory. However, these signals may instead reflect support mechanisms rather than the actual contents of memory. In particular, alpha-band oscillations have been tightly tied to spatial attention and may not reflect location-independent memory representations per se. To determine how sustained and oscillating EEG signals are related to attention and working memory, we attempted to decode which of 16 orientations was being held in working memory by human observers (both women and men). We found that sustained EEG activity could be used to decode the remembered orientation of a stimulus, even when the orientation of the stimulus varied independently of its location. Alpha-band oscillations also carried clear information about the location of the stimulus, but they provided little or no information about orientation independently of location. Thus, sustained potentials contain information about the object properties being maintained in working memory, consistent with previous evidence of a tight link between these potentials and working memory capacity. In contrast, alpha-band oscillations primarily carry location information, consistent with their link to spatial attention. SIGNIFICANCE STATEMENT Working memory plays a key role in cognition, and working memory is impaired in several neurological and psychiatric disorders. Previous research has suggested that human scalp EEG recordings contain signals that reflect the neural representation of information in working memory. However, to conclude that a neural signal actually represents the object being remembered, it is necessary to show that the signal contains fine-grained information about that object. Here, we show that sustained voltages in human EEG recordings contain fine-grained information about the

Technology Advancements in the Next Generation of Domain Agnostic Spatial Data Infrastructures

Science.gov (United States)

Golodoniuc, Pavel; Rankine, Terry; Box, Paul; Atkinson, Rob; Kostanski, Laura

2013-04-01

models and controlled vocabularies with enhanced linkage capabilities between datasets. These components are realised with reference implementations through the Spatial Information Services Stack (SISS). The proposed Linked Data approach to managing and using feature level identifiers to link information systems to SDI information resources, being developed through the Spatial Identifier Reference Framework (SIRF) for Social Protection in Indonesia Project. It uses Unique Resource Identifiers (URIs) to access feature information using traditional SDI data access interfaces. These identifiers are used to explicitly reference individual features. This is analogous to a citation database, enabling explicit reference to identified real world features within a particular dataset. Furthermore, these identifiers can be conceptualised as 'spatial bookmarks' and used to link multiple representations of the same feature in different layers of a traditional SDI, as well as linking spatial features to statistical information held in systems beyond SDI boundaries. The technology development effort has brought together over 20 participants including CSIRO, Geoscience Australia, Australian Bureau of Meteorology, Australian universities, and Australian government agencies as well as international initiatives, which have made significant contributions to the development of the semantic information management components of the SISS. The authors propose that through the use of the methodologies described in this paper, SDI can realise its potential as a spatial enablement mechanism that supports linking of multiple information systems, rather than remaining as a platform to deliver collections of spatial representations.

Accessing the mental space-Spatial working memory processes for language and vision overlap in precuneus.

Science.gov (United States)

Wallentin, Mikkel; Weed, Ethan; Østergaard, Leif; Mouridsen, Kim; Roepstorff, Andreas

2008-05-01

The "overlapping systems" theory of language function argues that linguistic meaning construction crucially relies on contextual information provided by "nonlinguistic" cognitive systems, such as perception and memory. This study examines whether linguistic processing of spatial relations established by reading sentences call on the same posterior parietal neural system involved in processing spatial relations set up through visual input. Subjects read simple sentences, which presented two agents in relation to each other, and were subsequently asked to evaluate spatial (e.g., "Was he turned towards her?") and equally concrete nonspatial content (e.g., "Was he older than her?"). We found that recall of the spatial content relative to the nonspatial content resulted in higher BOLD response in a dorsoposterior network of brain regions, most significantly in precuneus, strikingly overlapping a network previously shown to be involved in recall of spatial aspects of images depicting similar scenarios. This supports a neurocognitive model of language function, where sentences establish meaning by interacting with the perceptual and working memory networks of the brain. (Copyright) 2006 Wiley-Liss, Inc.

Agglomeration, accessibility and industrial location: evidence from spanish municipalities

OpenAIRE

Alañón Pardo, Ángel; Arauzo Carod, Josep María

2011-01-01

This paper deals with the location decisions of manufacturing firms in Spain. We analyse how agglomeration economies and transport accessibility influence the location decisions of firms at municipality level and in three industries. The main empirical contributions of this paper are the econometric techniques used (spatial econometric models) and some of the explanatory variables (local gross domestic product, road accessibility, and the characteristics of firms in neighbouring municipalitie...

Using spatial principles to optimize distributed computing for enabling the physical science discoveries.

Science.gov (United States)

Yang, Chaowei; Wu, Huayi; Huang, Qunying; Li, Zhenlong; Li, Jing

2011-04-05

Contemporary physical science studies rely on the effective analyses of geographically dispersed spatial data and simulations of physical phenomena. Single computers and generic high-end computing are not sufficient to process the data for complex physical science analysis and simulations, which can be successfully supported only through distributed computing, best optimized through the application of spatial principles. Spatial computing, the computing aspect of a spatial cyberinfrastructure, refers to a computing paradigm that utilizes spatial principles to optimize distributed computers to catalyze advancements in the physical sciences. Spatial principles govern the interactions between scientific parameters across space and time by providing the spatial connections and constraints to drive the progression of the phenomena. Therefore, spatial computing studies could better position us to leverage spatial principles in simulating physical phenomena and, by extension, advance the physical sciences. Using geospatial science as an example, this paper illustrates through three research examples how spatial computing could (i) enable data intensive science with efficient data/services search, access, and utilization, (ii) facilitate physical science studies with enabling high-performance computing capabilities, and (iii) empower scientists with multidimensional visualization tools to understand observations and simulations. The research examples demonstrate that spatial computing is of critical importance to design computing methods to catalyze physical science studies with better data access, phenomena simulation, and analytical visualization. We envision that spatial computing will become a core technology that drives fundamental physical science advancements in the 21st century.

Small-scale spatial variability of phenoxy acid mineralization potentials in transition zones with a multidisciplinary approach

DEFF Research Database (Denmark)

Pazarbasi, Meric Batioglu

The phenoxy acid group of herbicides is widely used to control broadleaf weeds, and it contaminates groundwater and surface water by leaching from agricultural soil or landfills. Due to the distinct vertical and horizontal gradients in nutrients and hydrologic exchange in transition zones...... in two transition zones, (1) the interfaces of unsaturated and saturated zones and (2) groundwater and surface water. Small-scale spatial variability of phenoxy acids was previously shown in topsoil; however, such small-scale studies are scarce in subsurface environments. We therefore studied the factors...... classes in the different mineralization potentials of discharge zones. Understanding of the natural attenuation potential of groundwater-surface water transition zones is important for stream water protection. In landfill-impacted groundwater-surface water interface, we further analyzed bacterial...

Resource reliability, accessibility and governance: pillars for managing water resources to achieve water security in Nepal

Science.gov (United States)

Biggs, E. M.; Duncan, J.; Atkinson, P.; Dash, J.

2013-12-01

As one of the world's most water-abundant countries, Nepal has plenty of water yet resources are both spatially and temporally unevenly distributed. With a population heavily engaged in subsistence farming, whereby livelihoods are entirely dependent on rain-fed agriculture, changes in freshwater resources can substantially impact upon survival. The two main sources of water in Nepal come from monsoon precipitation and glacial runoff. The former is essential for sustaining livelihoods where communities have little or no access to perennial water resources. Much of Nepal's population live in the southern Mid-Hills and Terai regions where dependency on the monsoon system is high and climate-environment interactions are intricate. Any fluctuations in precipitation can severely affect essential potable resources and food security. As the population continues to expand in Nepal, and pressures build on access to adequate and clean water resources, there is a need for institutions to cooperate and increase the effectiveness of water management policies. This research presents a framework detailing three fundamental pillars for managing water resources to achieve sustainable water security in Nepal. These are (i) resource reliability; (ii) adequate accessibility; and (iii) effective governance. Evidence is presented which indicates that water resources are adequate in Nepal to sustain the population. In addition, aspects of climate change are having less impact than previously perceived e.g. results from trend analysis of precipitation time-series indicate a decrease in monsoon extremes and interannual variation over the last half-century. However, accessibility to clean water resources and the potential for water storage is limiting the use of these resources. This issue is particularly prevalent given the heterogeneity in spatial and temporal distributions of water. Water governance is also ineffective due to government instability and a lack of continuity in policy

Open Access Publishing - Strengths and Strategies

Science.gov (United States)

Rasmussen, Martin

2010-05-01

The journal crisis and the demand for free accessibility to the results of publicly funded research were the main drivers of the Open Access movement since the late 1990's. Besides many academic institutions that support the different ways of Open Access publishing, there is a growing number of publishing houses that are specialized on this new access and business model of scholarly literature. The lecture provides an overview of the different kinds of Open Access publishing, discusses the variety of underlying business models, names the advantages and potentials for researches and the public, and overcomes some objections against Open Access. Besides the increased visibility and information supply, the topic of copyrights and exploitation rights will be discussed. Furthermore, it is a central aim of the presentation to show that Open Access does not only support full peer-review, but also provides the potential for even enhanced quality assurance. The financing of business models based on open accessible literature is another important part to be outlined in the lecture.

Vascular access in pediatric patients in the emergency department: types of access, indications, and complications [digest].

Science.gov (United States)

Whitney, Rachel; Langhan, Melissa; Pade, Kathryn H

2017-06-22

Vascular access is a potentially life-saving procedure that is a mainstay of emergency medicine practice. There are a number of challenges associated with obtaining and maintaining vascular access, and the choice of the route of access and equipment used will depend on patient- and provider-specific factors. In this issue, the indications and complications of peripheral intravenous access, intraosseous access, and central venous access are reviewed. Timely and effective assessment and management of difficult-access patients, pain control techniques that can assist vascular access, and contraindications to each type of vascular access are also discussed. [Points & Pearls is a digest of Pediatric Emergency Medicine Practice].

Detecting the Land-Cover Changes Induced by Large-Physical Disturbances Using Landscape Metrics, Spatial Sampling, Simulation and Spatial Analysis

Directory of Open Access Journals (Sweden)

Hone-Jay Chu

2009-08-01

Full Text Available The objectives of the study are to integrate the conditional Latin Hypercube Sampling (cLHS, sequential Gaussian simulation (SGS and spatial analysis in remotely sensed images, to monitor the effects of large chronological disturbances on spatial characteristics of landscape changes including spatial heterogeneity and variability. The multiple NDVI images demonstrate that spatial patterns of disturbed landscapes were successfully delineated by spatial analysis such as variogram, Moran’I and landscape metrics in the study area. The hybrid method delineates the spatial patterns and spatial variability of landscapes caused by these large disturbances. The cLHS approach is applied to select samples from Normalized Difference Vegetation Index (NDVI images from SPOT HRV images in the Chenyulan watershed of Taiwan, and then SGS with sufficient samples is used to generate maps of NDVI images. In final, the NDVI simulated maps are verified using indexes such as the correlation coefficient and mean absolute error (MAE. Therefore, the statistics and spatial structures of multiple NDVI images present a very robust behavior, which advocates the use of the index for the quantification of the landscape spatial patterns and land cover change. In addition, the results transferred by Open Geospatial techniques can be accessed from web-based and end-user applications of the watershed management.

Job access and the spatial mobility trajectories of higher education graduates in the Netherlands

NARCIS (Netherlands)

Middeldorp, Marten; Edzes, Arend; van Dijk, Jouke; Ritschard, Gilbert; Studer, Matthias

2016-01-01

The successfulness of the transition from education into working life is closely related to further career success. Graduates with good access to jobs earn higher wages and have lower chances of being unemployed. Access to jobs at the start of the career is therefore an important determinant of

The impact of opening hours on the equity of individual space-time accessibility.

NARCIS (Netherlands)

Delafontaine, M.; Neutens, T.; Schwanen, T.; Weghe, N. van der

2011-01-01

While many studies have concentrated on the effects of the spatial distribution of services on individual accessibility, only little is known about the ways in which equity of individual accessibility is affected by the temporal organisation of service delivery. This paper seeks to deepen our

Web accessibility standards and disability: developing critical perspectives on accessibility.

Science.gov (United States)

Lewthwaite, Sarah

2014-01-01

Currently, dominant web accessibility standards do not respect disability as a complex and culturally contingent interaction; recognizing that disability is a variable, contrary and political power relation, rather than a biological limit. Against this background there is clear scope to broaden the ways in which accessibility standards are understood, developed and applied. Commentary. The values that shape and are shaped by legislation promote universal, statistical and automated approaches to web accessibility. This results in web accessibility standards conveying powerful norms fixing the relationship between technology and disability, irrespective of geographical, social, technological or cultural diversity. Web accessibility standards are designed to enact universal principles; however, they express partial and biopolitical understandings of the relation between disability and technology. These values can be limiting, and potentially counter-productive, for example, for the majority of disabled people in the "Global South" where different contexts constitute different disabilities and different experiences of web access. To create more robust, accessible outcomes for disabled people, research and standards practice should diversify to embrace more interactional accounts of disability in different settings. Implications for Rehabilitation Creating accessible experiences is an essential aspect of rehabilitation. Web standards promote universal accessibility as a property of an online resource or service. This undervalues the importance of the user's intentions, expertize, their context, and the complex social and cultural nature of disability. Standardized, universal approaches to web accessibility may lead to counterproductive outcomes for disabled people whose impairments and circumstances do not meet Western disability and accessibility norms. Accessible experiences for rehabilitation can be enhanced through an additional focus on holistic approaches to

Geographical modelling based on spatial differentiation of fire brigade actions: A case study of Brno, Czech Republic

Directory of Open Access Journals (Sweden)

Popelínský Jan

2017-03-01

Full Text Available The paper analyzes crisis situations solved by The Fire Rescue Service of the South Moravian Region (FRS in the city of Brno during 24 weeks between 7th April 2013 and 20th September 2013. The article deals briefly with all FRS actions and then focuses on fires. The open-access database of FRS is used for analysis. It is accessed from a database of the innovative web application StreetAlert, which allows users to learn about current fire brigade actions in the specified distance from the mobile phone. The data are processed in PostgreSQL and then spatial analysis is performed using the most detailed administrative division of the city – basic settlement units. As this division of urban space is used also in the most recent Czech census (2011, it is possible to use sociodemographic statistical data for comparison. The article identifies spatial regularities in the distribution of fires, describes the structure of the fires in terms of the type of event (fires of waste, fires of grass and forest, fires of buildings, discovers their possible dependence on the specific characteristics of urban space, finds potentially dangerous places (kernel density analysis, draws valid conclusions applicable to similar settlements, and shows the possible use of the data for local government. The main benefit of the research lies in revealing the spatial distribution of the examined phenomena.

Spatial Interaction Modeling to Identify Potentially Exposed Populations during RDD or IND Terrorism Incidents

International Nuclear Information System (INIS)

Regens, J.L.; Gunter, J.T.; Gupta, S.

2009-01-01

Homeland Security Presidential Directive no.5 (HSPD-5) Management of Domestic Incidents and Department of Homeland Security (DHS) Planning Guidance for Protection and Recovery Following Radiological Dispersal Device (RDD) and Improvised Nuclear Device (IND) Incidents underscore the need to delineate radiological emergency guidance applicable to remedial action and recovery following an RDD or IND incident. Rapid delineation of the population potentially exposed to ionizing radiation from fallout during terrorist incidents involving RDDs or low-yield nuclear devices (≤ 20 KT) is necessary for effective medical response and incident management as part of the recovery process. This paper illustrates the application of spatial interaction models to allocate population data for a representative U.S. urban area (≅1.3M people; 1,612.27 km 2 area) at a geographical scale relevant for accurately estimating risk given dose concentrations. Estimated total dose equivalents (TEDE) are calculated for isopleths moving away from the detonation point for typical release scenarios. Population is estimated within the TEDE zones using Euclidean distances between zip code polygon centroids generated in ArcGIS version 9.1 with distance decay determined by regression analysis to apportion origin-destination pairs to a population count and density matrix on a spatial basis for daytime and night-time release scenarios. (authors)

Two-dimensional spatial survey of the plasma potential and electric field in a pulsed bipolar magnetron discharge

International Nuclear Information System (INIS)

Vetushka, A.; Karkari, S.K.; Bradley, J.W.

2004-01-01

Emissive and Langmuir probe techniques have been used to obtain two-dimensional (2D) spatial maps of the plasma potential V p , electric field E, and ion trajectories in a pulsed bipolar magnetron discharge. The magnetron was pulsed at a frequency of 100 kHz, with a 50% duty cycle and operated at an argon pressure of 0.74 Pa. The pulse wave form was characterized by three distinct phases: the 'overshoot', 'reverse', and 'on' phases. In the 'on' phase of the pulse, when the cathode voltage is driven to -670 V, the 2D spatial distribution of V p has a similar form to that in dc magnetron, with significant axial and radial electric fields in the bulk plasma, accelerating ions to the sheath edge above the cathode racetrack region. During the 'overshoot' phase (duration 200 ns), V p is raised to values greater than +330 V, more than 100 V above the cathode potential, with E pointing away from the target. In the 'reverse' phase V p has a value of +45 V at all measured positions, 2 V more positive than the target potential. In this phase there is no electric field present in the plasma. In the bulk of the plasma, the results from Langmuir probe and the emissive probe are in good agreement, however, in one particular region of the plasma outside the radius of the cathode, the emissive probe measurements are consistently more positive (up to 45 V in the 'on' time). This discrepancy is discussed in terms of the different frequency response of the probes and their perturbation of the plasma. A simple circuit model of the plasma-probe system has been proposed to explain our results. A brief discussion of the effect of the changing plasma potential distribution on the operation of the magnetron is given

Mapping of soil organic carbon stocks for spatially explicit assessments of climate change mitigation potential

International Nuclear Information System (INIS)

Vågen, Tor-Gunnar; Winowiecki, Leigh A

2013-01-01

Current methods for assessing soil organic carbon (SOC) stocks are generally not well suited for understanding variations in SOC stocks in landscapes. This is due to the tedious and time-consuming nature of the sampling methods most commonly used to collect bulk density cores, which limits repeatability across large areas, particularly where information is needed on the spatial dynamics of SOC stocks at scales relevant to management and for spatially explicit targeting of climate change mitigation options. In the current study, approaches were explored for (i) field-based estimates of SOC stocks and (ii) mapping of SOC stocks at moderate to high resolution on the basis of data from four widely contrasting ecosystems in East Africa. Estimated SOC stocks for 0–30 cm depth varied both within and between sites, with site averages ranging from 2 to 8 kg m −2 . The differences in SOC stocks were determined in part by rainfall, but more importantly by sand content. Results also indicate that managing soil erosion is a key strategy for reducing SOC loss and hence in mitigation of climate change in these landscapes. Further, maps were developed on the basis of satellite image reflectance data with multiple R-squared values of 0.65 for the independent validation data set, showing variations in SOC stocks across these landscapes. These maps allow for spatially explicit targeting of potential climate change mitigation efforts through soil carbon sequestration, which is one option for climate change mitigation and adaptation. Further, the maps can be used to monitor the impacts of such mitigation efforts over time. (letter)

Spatial Linkage and Urban Expansion: AN Urban Agglomeration View

Science.gov (United States)

Jiao, L. M.; Tang, X.; Liu, X. P.

2017-09-01

Urban expansion displays different characteristics in each period. From the perspective of the urban agglomeration, studying the spatial and temporal characteristics of urban expansion plays an important role in understanding the complex relationship between urban expansion and network structure of urban agglomeration. We analyze urban expansion in the Yangtze River Delta Urban Agglomeration (YRD) through accessibility to and spatial interaction intensity from core cities as well as accessibility of road network. Results show that: (1) Correlation between urban expansion intensity and spatial indicators such as location and space syntax variables is remarkable and positive, while it decreases after rapid expansion. (2) Urban expansion velocity displays a positive correlation with spatial indicators mentioned above in the first (1980-1990) and second (1990-2000) period. However, it exhibits a negative relationship in the third period (2000-2010), i.e., cities located in the periphery of urban agglomeration developing more quickly. Consequently, the hypothesis of convergence of urban expansion in rapid expansion stage is put forward. (3) Results of Zipf's law and Gibrat's law show urban expansion in YRD displays a convergent trend in rapid expansion stage, small and medium-sized cities growing faster. This study shows that spatial linkage plays an important but evolving role in urban expansion within the urban agglomeration. In addition, it serves as a reference to the planning of Yangtze River Delta Urban Agglomeration and regulation of urban expansion of other urban agglomerations.

Rapid Fear Detection Relies on High Spatial Frequencies

NARCIS (Netherlands)

Stein, T.; Seymour, K.; Hebart, M.N.; Sterzer, P.

Signals of threat—such as fearful faces—are processed with priority and have privileged access to awareness. This fear advantage is commonly believed to engage a specialized subcortical pathway to the amygdala that bypasses visual cortex and processes predominantly low-spatial-frequency information

High spatial correspondence at a columnar level between activation and resting state fMRI signals and local field potentials.

Science.gov (United States)

Shi, Zhaoyue; Wu, Ruiqi; Yang, Pai-Feng; Wang, Feng; Wu, Tung-Lin; Mishra, Arabinda; Chen, Li Min; Gore, John C

2017-05-16

Although blood oxygenation level-dependent (BOLD) fMRI has been widely used to map brain responses to external stimuli and to delineate functional circuits at rest, the extent to which BOLD signals correlate spatially with underlying neuronal activity, the spatial relationships between stimulus-evoked BOLD activations and local correlations of BOLD signals in a resting state, and whether these spatial relationships vary across functionally distinct cortical areas are not known. To address these critical questions, we directly compared the spatial extents of stimulated activations and the local profiles of intervoxel resting state correlations for both high-resolution BOLD at 9.4 T and local field potentials (LFPs), using 98-channel microelectrode arrays, in functionally distinct primary somatosensory areas 3b and 1 in nonhuman primates. Anatomic images of LFP and BOLD were coregistered within 0.10 mm accuracy. We found that the point spread functions (PSFs) of BOLD and LFP responses were comparable in the stimulus condition, and both estimates of activations were slightly more spatially constrained than local correlations at rest. The magnitudes of stimulus responses in area 3b were stronger than those in area 1 and extended in a medial to lateral direction. In addition, the reproducibility and stability of stimulus-evoked activation locations within and across both modalities were robust. Our work suggests that the intrinsic resolution of BOLD is not a limiting feature in practice and approaches the intrinsic precision achievable by multielectrode electrophysiology.

A look back on how far to walk: Systematic review and meta-analysis of physical access to skilled care for childbirth in Sub-Saharan Africa.

Directory of Open Access Journals (Sweden)

Kerry L M Wong

Full Text Available To (i summarize the methods undertaken to measure physical accessibility as the spatial separation between women and health services, and (ii establish the extent to which distance to skilled care for childbirth affects utilization in Sub-Saharan Africa.We defined spatial separation as the distance/travel time between women and skilled care services. The use of skilled care at birth referred to either the location or attendant of childbirth. The main criterion for inclusion was any quantification of the relationship between spatial separation and use of skilled care at birth. The approaches undertaken to measure distance/travel time were summarized in a narrative format. We obtained pooled adjusted odds ratios (aOR from studies that controlled for financial means, education and (perceived need of care in a meta-analysis.57 articles were included (40 studied distance and 25 travel time, in which distance/travel time were found predominately self-reported or estimated in a geographic information system based on geographic coordinates. Approaches of distance/travel time measurement were generally poorly detailed, especially for self-reported data. Crucial features such as start point of origin and the mode of transportation for travel time were most often unspecified. Meta-analysis showed that increased distance to maternity care had an inverse association with utilization (n = 10, pooled aOR = 0.90/1km, 95%CI = 0.85-0.94. Distance from a hospital for rural women showed an even more pronounced effect on utilization (n = 2, pooled aOR = 0.58/1km increase, 95%CI = 0.31,1.09. The effect of spatial separation appears to level off beyond critical point when utilization was generally low.Although the reporting and measurements of spatial separation in low-resource settings needs further development, we found evidence that a lack of geographic access impedes use. Utilization is conditioned on access, researchers and policy makers should therefore

A look back on how far to walk: Systematic review and meta-analysis of physical access to skilled care for childbirth in Sub-Saharan Africa.

Science.gov (United States)

Wong, Kerry L M; Benova, Lenka; Campbell, Oona M R

2017-01-01

To (i) summarize the methods undertaken to measure physical accessibility as the spatial separation between women and health services, and (ii) establish the extent to which distance to skilled care for childbirth affects utilization in Sub-Saharan Africa. We defined spatial separation as the distance/travel time between women and skilled care services. The use of skilled care at birth referred to either the location or attendant of childbirth. The main criterion for inclusion was any quantification of the relationship between spatial separation and use of skilled care at birth. The approaches undertaken to measure distance/travel time were summarized in a narrative format. We obtained pooled adjusted odds ratios (aOR) from studies that controlled for financial means, education and (perceived) need of care in a meta-analysis. 57 articles were included (40 studied distance and 25 travel time), in which distance/travel time were found predominately self-reported or estimated in a geographic information system based on geographic coordinates. Approaches of distance/travel time measurement were generally poorly detailed, especially for self-reported data. Crucial features such as start point of origin and the mode of transportation for travel time were most often unspecified. Meta-analysis showed that increased distance to maternity care had an inverse association with utilization (n = 10, pooled aOR = 0.90/1km, 95%CI = 0.85-0.94). Distance from a hospital for rural women showed an even more pronounced effect on utilization (n = 2, pooled aOR = 0.58/1km increase, 95%CI = 0.31,1.09). The effect of spatial separation appears to level off beyond critical point when utilization was generally low. Although the reporting and measurements of spatial separation in low-resource settings needs further development, we found evidence that a lack of geographic access impedes use. Utilization is conditioned on access, researchers and policy makers should therefore prioritize quality

Leptin attenuates the detrimental effects of β-amyloid on spatial memory and hippocampal later-phase long term potentiation in rats.

Science.gov (United States)

Tong, Jia-Qing; Zhang, Jun; Hao, Ming; Yang, Ju; Han, Yu-Fei; Liu, Xiao-Jie; Shi, Hui; Wu, Mei-Na; Liu, Qing-Song; Qi, Jin-Shun

2015-07-01

β-Amyloid (Aβ) is the main component of amyloid plaques developed in the brain of patients with Alzheimer's disease (AD). The increasing burden of Aβ in the cortex and hippocampus is closely correlated with memory loss and cognition deficits in AD. Recently, leptin, a 16kD peptide derived mainly from white adipocyte tissue, has been appreciated for its neuroprotective function, although less is known about the effects of leptin on spatial memory and synaptic plasticity. The present study investigated the neuroprotective effects of leptin against Aβ-induced deficits in spatial memory and in vivo hippocampal late-phase long-term potentiation (L-LTP) in rats. Y maze spontaneous alternation was used to assess short term working memory, and the Morris water maze task was used to assess long term reference memory. Hippocampal field potential recordings were performed to observe changes in L-LTP. We found that chronically intracerebroventricular injection of leptin (1μg) effectively alleviated Aβ1-42 (20μg)-induced spatial memory impairments of Y maze spontaneous alternation and Morris water maze. In addition, chronic administration of leptin also reversed Aβ1-42-induced suppression of in vivo hippocampal L-LTP in rats. Together, these results suggest that chronic leptin treatments reversed Aβ-induced deficits in learning and memory and the maintenance of L-LTP. Copyright © 2015 Elsevier Inc. All rights reserved.

Natura 2000 and spatial planning

NARCIS (Netherlands)

Grift-Simeonova, van der V.S.; Bouwma, I.M.; Grift, van der E.A.; Sunyer, Carlos; Manteiga, Lola; Külvik, Mart; Suškevičs, Monika; Dimitrov, S.; Dimitrova, Ana

2017-01-01

Spatial planning which reconciles nature conservation with other policies' objectives can be a useful tool for implementing the EU nature legislation. However, a thorough exploration of the potential role of spatial planning and its instruments for the implementation of Natura 2000 has not yet been

Event-related potential evidence of accessing gender stereotypes to aid source monitoring.

Science.gov (United States)

Leynes, P Andrew; Crawford, Jarret T; Radebaugh, Anne M; Taranto, Elizabeth

2013-01-23

Source memory for the speaker's voice (male or female) was investigated when semantic knowledge (gender stereotypes) could and could not inform the episodic source judgment while event-related potentials (ERPs) were recorded. Source accuracy was greater and response times were faster when stereotypes could predict the speaker's voice at test. Recollection supported source judgments in both conditions as indicated by significant parietal "old/new" ERP effects (500-800ms). Prototypical late ERP effects (the right frontal "old/new" effect and the late posterior negativity, LPN) were evident when source judgment was based solely on episodic memory. However, these two late ERP effects were diminished and a novel, frontal-negative ERP with left-central topography was observed when stereotypes aided source judgments. This pattern of ERP activity likely reflects activation of left frontal or left temporal lobes when semantic knowledge, in the form of a gender stereotype, is accessed to inform the episodic source judgment. Copyright © 2012 Elsevier B.V. All rights reserved.

Comparison of the common spatial interpolation methods used to analyze potentially toxic elements surrounding mining regions.

Science.gov (United States)

Ding, Qian; Wang, Yong; Zhuang, Dafang

2018-04-15

The appropriate spatial interpolation methods must be selected to analyze the spatial distributions of Potentially Toxic Elements (PTEs), which is a precondition for evaluating PTE pollution. The accuracy and effect of different spatial interpolation methods, which include inverse distance weighting interpolation (IDW) (power = 1, 2, 3), radial basis function interpolation (RBF) (basis function: thin-plate spline (TPS), spline with tension (ST), completely regularized spline (CRS), multiquadric (MQ) and inverse multiquadric (IMQ)) and ordinary kriging interpolation (OK) (semivariogram model: spherical, exponential, gaussian and linear), were compared using 166 unevenly distributed soil PTE samples (As, Pb, Cu and Zn) in the Suxian District, Chenzhou City, Hunan Province as the study subject. The reasons for the accuracy differences of the interpolation methods and the uncertainties of the interpolation results are discussed, then several suggestions for improving the interpolation accuracy are proposed, and the direction of pollution control is determined. The results of this study are as follows: (i) RBF-ST and OK (exponential) are the optimal interpolation methods for As and Cu, and the optimal interpolation method for Pb and Zn is RBF-IMQ. (ii) The interpolation uncertainty is positively correlated with the PTE concentration, and higher uncertainties are primarily distributed around mines, which is related to the strong spatial variability of PTE concentrations caused by human interference. (iii) The interpolation accuracy can be improved by increasing the sample size around the mines, introducing auxiliary variables in the case of incomplete sampling and adopting the partition prediction method. (iv) It is necessary to strengthen the prevention and control of As and Pb pollution, particularly in the central and northern areas. The results of this study can provide an effective reference for the optimization of interpolation methods and parameters for

Exploring the unequal landscapes of healthcare accessibility in lower-income urban neighborhoods through qualitative inquiry

NARCIS (Netherlands)

Hawthorne, T.; Kwan, M.-P.

2013-01-01

Geographers and public health researchers recognize that healthcare accessibility is a multi-dimensional concept contingent upon the interplay of a variety of spatial and non-spatial factors, including geographic distance, cost, availability, and quality of services. Understanding such complex

UUI: Reusable Spatial Data Services in Unified User Interface at NASA GES DISC

Science.gov (United States)

Petrenko, M.; Hegde, M.; Bryant, K.; Pham, L.

2016-12-01

Unified User Interface (UUI) is a next-generation operational data access tool that has been developed at Goddard Earth Sciences Data and Information Services Center (GES DISC) to provide a simple, unified, and intuitive one-stop shop experience for the key data services available at GES DISC, including subsetting (Simple Subset Wizard - SSW), granule file search (Mirador), plotting (Giovanni), and other legacy spatial data services. UUI has been built based on a flexible infrastructure of reusable web services - self-contained building blocks that can easily be plugged into spatial applications, including third-party clients or services, to easily enable new functionality as new datasets and services become available. In this presentation, we will discuss our experience in designing UUI services based on open industry standards. We will also explain how the resulting framework can be used for a rapid development, deployment, and integration of spatial data services, facilitating efficient access and dissemination of spatial data sets.

UUI: Reusable Spatial Data Services in Unified User Interface at NASA GES DISC

Science.gov (United States)

Petrenko, Maksym; Hegde, Mahabaleshwa; Bryant, Keith; Pham, Long B.

2016-01-01

Unified User Interface (UUI) is a next-generation operational data access tool that has been developed at Goddard Earth Sciences Data and Information Services Center(GES DISC) to provide a simple, unified, and intuitive one-stop shop experience for the key data services available at GES DISC, including subsetting (Simple Subset Wizard -SSW), granule file search (Mirador), plotting (Giovanni), and other legacy spatial data services. UUI has been built based on a flexible infrastructure of reusable web services self-contained building blocks that can easily be plugged into spatial applications, including third-party clients or services, to easily enable new functionality as new datasets and services become available. In this presentation, we will discuss our experience in designing UUI services based on open industry standards. We will also explain how the resulting framework can be used for a rapid development, deployment, and integration of spatial data services, facilitating efficient access and dissemination of spatial data sets.

A Third-Generation Adaptive Statistical Iterative Reconstruction Technique: Phantom Study of Image Noise, Spatial Resolution, Lesion Detectability, and Dose Reduction Potential.

Science.gov (United States)

Euler, André; Solomon, Justin; Marin, Daniele; Nelson, Rendon C; Samei, Ehsan

2018-06-01

The purpose of this study was to assess image noise, spatial resolution, lesion detectability, and the dose reduction potential of a proprietary third-generation adaptive statistical iterative reconstruction (ASIR-V) technique. A phantom representing five different body sizes (12-37 cm) and a contrast-detail phantom containing lesions of five low-contrast levels (5-20 HU) and three sizes (2-6 mm) were deployed. Both phantoms were scanned on a 256-MDCT scanner at six different radiation doses (1.25-10 mGy). Images were reconstructed with filtered back projection (FBP), ASIR-V with 50% blending with FBP (ASIR-V 50%), and ASIR-V without blending (ASIR-V 100%). In the first phantom, noise properties were assessed by noise power spectrum analysis. Spatial resolution properties were measured by use of task transfer functions for objects of different contrasts. Noise magnitude, noise texture, and resolution were compared between the three groups. In the second phantom, low-contrast detectability was assessed by nine human readers independently for each condition. The dose reduction potential of ASIR-V was estimated on the basis of a generalized linear statistical regression model. On average, image noise was reduced 37.3% with ASIR-V 50% and 71.5% with ASIR-V 100% compared with FBP. ASIR-V shifted the noise power spectrum toward lower frequencies compared with FBP. The spatial resolution of ASIR-V was equivalent or slightly superior to that of FBP, except for the low-contrast object, which had lower resolution. Lesion detection significantly increased with both ASIR-V levels (p = 0.001), with an estimated radiation dose reduction potential of 15% ± 5% (SD) for ASIR-V 50% and 31% ± 9% for ASIR-V 100%. ASIR-V reduced image noise and improved lesion detection compared with FBP and had potential for radiation dose reduction while preserving low-contrast detectability.

Denitrification potential of riparian soils in relation to multiscale spatial environmental factors: a case study of a typical watershed, China.

Science.gov (United States)

Wei, Jianbing; Feng, Hao; Cheng, Quanguo; Gao, Shiqian; Liu, Haiyan

2017-02-01

The objective of this study was to test the hypothesis that environmental regulators of riparian zone soil denitrification potential differ according to spatial scale within a watershed; consequently, a second objective was to provide spatial strategies for conserving and restoring the purification function of runoff in riparian ecosystems. The results show that soil denitrification in riparian zones was more heterogeneous at the profile scale than at the cross-section and landscape scales. At the profile scale, biogeochemical factors (including soil total organic carbon, total nitrogen, and nitrate-nitrogen) were the major direct regulators of the spatial distribution of soil denitrification enzyme activity (DEA). At the cross-section scale, factors included distance from river bank and vegetation density, while landscape-scale factors, including topographic index, elevation, and land use types, indirectly regulated the spatial distribution of DEA. At the profile scale, soil DEA was greatest in the upper soil layers. At the cross-section scale, maximum soil DEA occurred in the mid-part of the riparian zone. At the landscape scale, soil DEA showed an increasing trend towards downstream sites, except for those in urbanized areas.

Access to environmental resources and physical activity levels of adults in Hawaii.

Science.gov (United States)

Geller, Karly S; Nigg, Claudio R; Ollberding, Nicholas J; Motl, Robert W; Horwath, Caroline; Dishman, Rodney K

2015-03-01

Examine associations between physical activity (PA) and spatial accessibility to environmental PA resources in Hawaii. Metabolic equivalents (METs) of mild, moderate, and strenuous PA were compared for accessibility with environmental PA resources within a population-based sample of Hawaiian adults (n = 381). Multiple linear regression estimated differences in PA levels for residing further from a PA resource or residing in an area with a greater number of resources. No associations were found in the total sample. Analyses within subsamples stratified by ethnicity revealed that greater spatial accessibility to a PA resource was positively associated with strenuous PA among Caucasians (P = .04) but negatively associated with moderate PA among Native Hawaiians (P = .00). The lack of association in the total sample may be a consequence of Hawaii's unique environment. Results of stratified sample analyses are unique, providing groundwork for future examinations within parallel environments and among similar ethnic groups. © 2012 APJPH.

Assessing Accessibility and Transport Infrastructure Inequities in Administrative Units in Serbia’s Danube Corridor Based on Multi-Criteria Analysis and Gis Mapping Tools

Directory of Open Access Journals (Sweden)

Ana VULEVIC

2018-02-01

Full Text Available The Danube Regions, especially the sub-national units of governance, must be ready to play an active role in spatial development policies. A precondition for this is good accessibility and the coordinated development of all transport systems in the Danube corridor. The main contribution of this paper is to provide a multi-criteria model for potential decision making related to the evaluation of transportation accessibility in Serbia’s Danube Corridor. Geographic Information Systems (GIS, based on maps, indicate the existing counties’ transport infrastructures inequities (between well-connected and isolated counties in terms of accessibility to central places. Through the research, relevant indicators have been identifi ed. This provides an outline of transportation perspectives regarding the development achieved and also fosters the increase of transportation accessibility in some peripheral Serbian Danube administrative units – counties (Nomenclature of Territorial Units for Statistics level 3 – NUTS 3.

Improving Nearest Neighbour Search in 3D Spatial Access Method

DEFF Research Database (Denmark)

Suhaibah, A.; Rahman, A. A.; Uznir, U.

2016-01-01

are still facing with unresolved issues such as overlapping among nodes and repetitive data entry. This situation will perform an excessive Input/Output (IO) operation which is inefficient for data retrieval. The situation will become more crucial while dealing with 3D data. The size of 3D data is usually...... and the accessed page. The proposed structure also produced minimal Input/Output operation. The query response time is also outperformed compared to the other competitor. For future outlook of this research several possible applications are discussed and summarized....

A Potential Synergy Connecting Educational Leadership, The Geoscience Community, and Spatial Data

Science.gov (United States)

Branch, B. D.

2008-12-01

The effort to promote more geosciences numbers and greater diversity should reference considerations of federal policy. In congruence, institutions need to include geosciences education in the K-12 curriculum in order to increase the numbers of geoscientists and to increase diversity among geoscientists. For example, No Child Left Behind stated public entities should, ""(1) to carry out programs that prepare prospective teachers to use advanced technology to prepare all students to meet challenging", section 1051 sub section 221. Moreover, Executive Order 12906, the Spatial Data Infrastructure Act, requires all federal agencies to manage their spatial data. Such compliance may influence the job market, education and policy makers to see that spatial thinking transcends the standard course of study. Namely, educational leadership and policy have to be a vital aid to augment the geosciences experience through the K-12 experience and as an inclusion activity in the standard course of study agenda. A simple endorsement by the National Academy of Sciences (2006), in their work titled Learning to think spatially: GIS as a support system in the K-12 curriculum, who stated, "Spatial thinking can be learned, and it can and should be taught at all levels in the education system" (p.3). Such may not be enough to gain the attention and time consideration of educational leadership. Therefore, the challenge for progressive advocates of geosciences is that some may have to consider educational leadership as new frontier to push such policy and research issues.

Spatial Air Index Based on Largest Empty Rectangles for Non-Flat Wireless Broadcast in Pervasive Computing

Directory of Open Access Journals (Sweden)

Jun-Hong Shen

2016-11-01

Full Text Available In pervasive computing, location-based services (LBSs are valuable for mobile clients based on their current locations. LBSs use spatial window queries to enable useful applications for mobile clients. Based on skewed access patterns of mobile clients, non-flat wireless broadcast has been shown to efficiently disseminate spatial objects to mobile clients. In this paper, we consider a scenario in which spatial objects are broadcast to mobile clients over a wireless channel in a non-flat broadcast manner to process window queries. For such a scenario, we propose an efficient spatial air index method to handle window query access in non-flat wireless broadcast environments. The concept of largest empty rectangles is used to avoid unnecessary examination of the broadcast content, thus reducing the processing time for window queries. Simulation results show that the proposed spatial air index method outperforms the existing methods under various settings.

Semantic Mediation via Access Broker: the OWS-9 experiment

Science.gov (United States)

Santoro, Mattia; Papeschi, Fabrizio; Craglia, Massimo; Nativi, Stefano

2013-04-01

Even with the use of common data models standards to publish and share geospatial data, users may still face semantic inconsistencies when they use Spatial Data Infrastructures - especially in multidisciplinary contexts. Several semantic mediation solutions exist to address this issue; they span from simple XSLT documents to transform from one data model schema to another, to more complex services based on the use of ontologies. This work presents the activity done in the context of the OGC Web Services Phase 9 (OWS-9) Cross Community Interoperability to develop a semantic mediation solution by enhancing the GEOSS Discovery and Access Broker (DAB). This is a middleware component that provides harmonized access to geospatial datasets according to client applications preferred service interface (Nativi et al. 2012, Vaccari et al. 2012). Given a set of remote feature data encoded in different feature schemas, the objective of the activity was to use the DAB to enable client applications to transparently access the feature data according to one single schema. Due to the flexible architecture of the Access Broker, it was possible to introduce a new transformation type in the configured chain of transformations. In fact, the Access Broker already provided the following transformations: Coordinate Reference System (CRS), spatial resolution, spatial extent (e.g., a subset of a data set), and data encoding format. A new software module was developed to invoke the needed external semantic mediation service and harmonize the accessed features. In OWS-9 the Access Broker invokes a SPARQL WPS to retrieve mapping rules for the OWS-9 schemas: USGS, and NGA schema. The solution implemented to address this problem shows the flexibility and extensibility of the brokering framework underpinning the GEO DAB: new services can be added to augment the number of supported schemas without the need to modify other components and/or software modules. Moreover, all other transformations (CRS

A spatial national health facility database for public health sector planning in Kenya in 2008

Directory of Open Access Journals (Sweden)

Gething Peter W

2009-03-01

Full Text Available Abstract Background Efforts to tackle the enormous burden of ill-health in low-income countries are hampered by weak health information infrastructures that do not support appropriate planning and resource allocation. For health information systems to function well, a reliable inventory of health service providers is critical. The spatial referencing of service providers to allow their representation in a geographic information system is vital if the full planning potential of such data is to be realized. Methods A disparate series of contemporary lists of health service providers were used to update a public health facility database of Kenya last compiled in 2003. These new lists were derived primarily through the national distribution of antimalarial and antiretroviral commodities since 2006. A combination of methods, including global positioning systems, was used to map service providers. These spatially-referenced data were combined with high-resolution population maps to analyze disparity in geographic access to public health care. Findings The updated 2008 database contained 5,334 public health facilities (67% ministry of health; 28% mission and nongovernmental organizations; 2% local authorities; and 3% employers and other ministries. This represented an overall increase of 1,862 facilities compared to 2003. Most of the additional facilities belonged to the ministry of health (79% and the majority were dispensaries (91%. 93% of the health facilities were spatially referenced, 38% using global positioning systems compared to 21% in 2003. 89% of the population was within 5 km Euclidean distance to a public health facility in 2008 compared to 71% in 2003. Over 80% of the population outside 5 km of public health service providers was in the sparsely settled pastoralist areas of the country. Conclusion We have shown that, with concerted effort, a relatively complete inventory of mapped health services is possible with enormous potential for

A spatial national health facility database for public health sector planning in Kenya in 2008.

Science.gov (United States)

Noor, Abdisalan M; Alegana, Victor A; Gething, Peter W; Snow, Robert W

2009-03-06

Efforts to tackle the enormous burden of ill-health in low-income countries are hampered by weak health information infrastructures that do not support appropriate planning and resource allocation. For health information systems to function well, a reliable inventory of health service providers is critical. The spatial referencing of service providers to allow their representation in a geographic information system is vital if the full planning potential of such data is to be realized. A disparate series of contemporary lists of health service providers were used to update a public health facility database of Kenya last compiled in 2003. These new lists were derived primarily through the national distribution of antimalarial and antiretroviral commodities since 2006. A combination of methods, including global positioning systems, was used to map service providers. These spatially-referenced data were combined with high-resolution population maps to analyze disparity in geographic access to public health care. The updated 2008 database contained 5,334 public health facilities (67% ministry of health; 28% mission and nongovernmental organizations; 2% local authorities; and 3% employers and other ministries). This represented an overall increase of 1,862 facilities compared to 2003. Most of the additional facilities belonged to the ministry of health (79%) and the majority were dispensaries (91%). 93% of the health facilities were spatially referenced, 38% using global positioning systems compared to 21% in 2003. 89% of the population was within 5 km Euclidean distance to a public health facility in 2008 compared to 71% in 2003. Over 80% of the population outside 5 km of public health service providers was in the sparsely settled pastoralist areas of the country. We have shown that, with concerted effort, a relatively complete inventory of mapped health services is possible with enormous potential for improving planning. Expansion in public health care in Kenya has

Detecting spatial regimes in ecosystems

Science.gov (United States)

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.

Workshop AccessibleTV "Accessible User Interfaces for Future TV Applications"

Science.gov (United States)

Hahn, Volker; Hamisu, Pascal; Jung, Christopher; Heinrich, Gregor; Duarte, Carlos; Langdon, Pat

Approximately half of the elderly people over 55 suffer from some type of typically mild visual, auditory, motor or cognitive impairment. For them interaction, especially with PCs and other complex devices is sometimes challenging, although accessible ICT applications could make much of a difference for their living quality. Basically they have the potential to enable or simplify participation and inclusion in their surrounding private and professional communities. However, the availability of accessible user interfaces being capable to adapt to the specific needs and requirements of users with individual impairments is very limited. Although there are a number of APIs [1, 2, 3, 4] available for various platforms that allow developers to provide accessibility features within their applications, today none of them provides features for the automatic adaptation of multimodal interfaces being capable to automatically fit the individual requirements of users with different kinds of impairments. Moreover, the provision of accessible user interfaces is still expensive and risky for application developers, as they need special experience and effort for user tests. Today many implementations simply neglect the needs of elderly people, thus locking out a large portion of their potential users. The workshop is organized as part of the dissemination activity for the European-funded project GUIDE "Gentle user interfaces for elderly people", which aims to address this situation with a comprehensive approach for the realization of multimodal user interfaces being capable to adapt to the needs of users with different kinds of mild impairments. As application platform, GUIDE will mainly target TVs and Set-Top Boxes, such as the emerging Connected-TV or WebTV platforms, as they have the potential to address the needs of the elderly users with applications such as for home automation, communication or continuing education.

Geographic variations in cervical cancer risk in San Luis Potosí state, Mexico: A spatial statistical approach.

Science.gov (United States)

Terán-Hernández, Mónica; Ramis-Prieto, Rebeca; Calderón-Hernández, Jaqueline; Garrocho-Rangel, Carlos Félix; Campos-Alanís, Juan; Ávalos-Lozano, José Antonio; Aguilar-Robledo, Miguel

2016-09-29

Worldwide, Cervical Cancer (CC) is the fourth most common type of cancer and cause of death in women. It is a significant public health problem, especially in low and middle-income/Gross Domestic Product (GDP) countries. In the past decade, several studies of CC have been published, that identify the main modifiable and non-modifiable CC risk factors for Mexican women. However, there are no studies that attempt to explain the residual spatial variation in CC incidence In Mexico, i.e. spatial variation that cannot be ascribed to known, spatially varying risk factors. This paper uses a spatial statistical methodology that takes into account spatial variation in socio-economic factors and accessibility to health services, whilst allowing for residual, unexplained spatial variation in risk. To describe residual spatial variations in CC risk, we used generalised linear mixed models (GLMM) with both spatially structured and unstructured random effects, using a Bayesian approach to inference. The highest risk is concentrated in the southeast, where the Matlapa and Aquismón municipalities register excessive risk, with posterior probabilities greater than 0.8. The lack of coverage of Cervical Cancer-Screening Programme (CCSP) (RR 1.17, 95 % CI 1.12-1.22), Marginalisation Index (RR 1.05, 95 % CI 1.03-1.08), and lack of accessibility to health services (RR 1.01, 95 % CI 1.00-1.03) were significant covariates. There are substantial differences between municipalities, with high-risk areas mainly in low-resource areas lacking accessibility to health services for CC. Our results clearly indicate the presence of spatial patterns, and the relevance of the spatial analysis for public health intervention. Ignoring the spatial variability means to continue a public policy that does not tackle deficiencies in its national CCSP and to keep disadvantaging and disempowering Mexican women in regard to their health care.

The spatial comfort study of shophouse at Kampung Madras

Science.gov (United States)

Ginting, Y. U. U.; Ginting, N.; Zahrah, W.

2018-03-01

This Research comes from the increasing quantity of shophouse in downtown Medan and the suburban area. The condition of shophouse tend to have narrowly spaced rooms, the middle area of the house are poorly lighted, and lots of space left unused. This research is supported by many spatial issues from previous studies. This study is conducted to determine the level of comfort of shophouse as a function of living space and focused on the spatial aspect namely anthropometry, indoor space circulation, space requirement and function, spatial design and indoor visual. This study uses the descriptive method with the qualitative and quantitative approach. Data collection technique is done by field observation, questionnaire method is also used to get the respondent perception of the spatial comfort of a shophouse. The result indicates that the level of spatial comfort of the shophouse is an uncomfort. So the improvements in the circulation of access to the building, spatial design, lighting, and aeration are needed to improve the spatial comfort of a shophouse.

Spatial Correlation of PAN UWB-MIMO Channel Including User Dynamics

DEFF Research Database (Denmark)

Wang, Yu; Kovacs, Istvan Zsolt; Pedersen, Gert Frølund

. It is found the channel shows spatial correlated wideband power, and spatial uncorrelated complex channel coefficients at different frequencies and delays with respect to a correlation coefficient threshold of 0.7. The Kronecker model is proved not suitable for the investigated scenarios. The MIMO UWB channel......In this paper we present and analyze spatial correlation properties of indoor 4x2 MIMO UWB channels in personal area network (PAN) scenarios. The presented results are based on measurement of radio links between an access point like device and a hand held or belt mounted device with dynamic user...

Evaluating spatial patterns of dioxins in sediments to aid determination of potential implications for marine reptiles

Energy Technology Data Exchange (ETDEWEB)

Hermanussen, S.; Gaus, C. [National Research Centre for Environmental Toxicology, Brisbane (Australia); Limpus, C.J. [Queensland Environmental Protection Agency, Brisbane (Australia); Paepke, O. [ERGO Forschungsgesellschaft mbH, Hamburg (Germany); Blanshard, W. [Sea World, Gold Coast (Australia); Connell, D. [School of Public Health, Griffith Univ., Brisbane (Australia)

2004-09-15

Recent investigations have identified elevated concentrations of polychlorinated dibenzo-p-dioxins (dioxins) in marine sediments and wildlife of Queensland, Australia. While it has been demonstrated that the contamination is widespread and predominantly land-based, limited information exists on the pathways and fate of these compounds within the near-shore marine system. This environment supports unique and threatened species including green sea turtles (Chelonia mydas). Adult green turtles are predominantly herbivorous, feeding on seagrass and algae. Apart from initial migration to feeding grounds (at {proportional_to}10 years of age) and intermittent migrations to breeding grounds (at {proportional_to}30-50 years and thereafter), green turtles remain and feed within relatively small home ranges. Long life-span (50 years or more), near-shore feeding grounds and highly specialized food requirements render green turtles potentially vulnerable to contaminant exposure. Recent studies have shown a relationship between PCDD/F concentrations found in herbivorous marine wildlife and concentrations in sediments of their habitats. Hence, the spatial evaluation of sediment PCDD/F distribution may assist the assessment of green turtle exposure and its potential implications. The present study provides baseline information on green turtle PCDD/F concentrations in Queensland, Australia and investigates exposure pathways. In addition, spatial distribution of PCDD/Fs in sediments from known green turtle feeding regions is assessed using geographic information systems. This represents the first stage of a large scale investigation into the exposure and sensitivity of marine reptiles to dioxins and dioxin-like compounds and to evaluate whether poor health status observed in some populations may be related to contaminant exposure.

A spatial model for a stream networks of Citarik River with the environmental variables: potential of hydrogen (PH) and temperature

Science.gov (United States)

Bachrudin, A.; Mohamed, N. B.; Supian, S.; Sukono; Hidayat, Y.

2018-03-01

Application of existing geostatistical theory of stream networks provides a number of interesting and challenging problems. Most of statistical tools in the traditional geostatistics have been based on a Euclidean distance such as autocovariance functions, but for stream data is not permissible since it deals with a stream distance. To overcome this autocovariance developed a model based on the distance the flow with using convolution kernel approach (moving average construction). Spatial model for a stream networks is widely used to monitor environmental on a river networks. In a case study of a river in province of West Java, the objective of this paper is to analyze a capability of a predictive on two environmental variables, potential of hydrogen (PH) and temperature using ordinary kriging. Several the empirical results show: (1) The best fit of autocovariance functions for temperature and potential hydrogen (ph) of Citarik River is linear which also yields the smallest root mean squared prediction error (RMSPE), (2) the spatial correlation values between the locations on upstream and on downstream of Citarik river exhibit decreasingly

Pitfalls, Potentials, and Ethics of Online Survey Research: LGBTQ and Other Marginalized and Hard-to-Access Youths.

Science.gov (United States)

McInroy, Lauren B

2016-06-01

Online research methodologies may serve as an important mechanism for population-focused data collection in social work research. Online surveys have become increasingly prevalent in research inquiries with young people and have been acknowledged for their potential in investigating understudied and marginalized populations and subpopulations, permitting increased access to communities that tend to be less visible-and thus often less studied-in offline contexts. Lesbian, gay, bisexual, transgender, and queer (LGBTQ) young people are a socially stigmatized, yet digitally active, youth population whose participation in online surveys has been previously addressed in the literature. Many of the opportunities and challenges of online survey research identified with LGBTQ youths may be highly relevant to other populations of marginalized and hard-to-access young people, who are likely present in significant numbers in the online environment (for example, ethnoracialized youths and low-income youths). In this article, the utility of online survey methods with marginalized young people is discussed, and recommendations for social work research are provided.

Spatial cluster modelling

CERN Document Server

Lawson, Andrew B

2002-01-01

Research has generated a number of advances in methods for spatial cluster modelling in recent years, particularly in the area of Bayesian cluster modelling. Along with these advances has come an explosion of interest in the potential applications of this work, especially in epidemiology and genome research. In one integrated volume, this book reviews the state-of-the-art in spatial clustering and spatial cluster modelling, bringing together research and applications previously scattered throughout the literature. It begins with an overview of the field, then presents a series of chapters that illuminate the nature and purpose of cluster modelling within different application areas, including astrophysics, epidemiology, ecology, and imaging. The focus then shifts to methods, with discussions on point and object process modelling, perfect sampling of cluster processes, partitioning in space and space-time, spatial and spatio-temporal process modelling, nonparametric methods for clustering, and spatio-temporal ...

Rail Access to Yucca Mountain: Critical Issues

International Nuclear Information System (INIS)

Halstead, R. J.; Dilger, F.; Moore, R. C.

2003-01-01

The proposed Yucca Mountain repository site currently lacks rail access. The nearest mainline railroad is almost 100 miles away. Absence of rail access could result in many thousands of truck shipments of spent nuclear fuel and high-level radioactive waste. Direct rail access to the repository could significantly reduce the number of truck shipments and total shipments. The U.S. Department of Energy (DOE) identified five potential rail access corridors, ranging in length from 98 miles to 323 miles, in the Final Environmental Impact Statement (FEIS) for Yucca Mountain. The FEIS also considers an alternative to rail spur construction, heavy-haul truck (HHT) delivery of rail casks from one of three potential intermodal transfer stations. The authors examine the feasibility and cost of the five rail corridors, and DOE's alternative proposal for HHT transport. The authors also address the potential for rail shipments through the Las Vegas metropolitan area

Accessing the mental space - Spatial working memory processes for language and vision overlap in precuneus

DEFF Research Database (Denmark)

Wallentin, Mikkel; Weed, Ethan; Østergaard, Leif

2008-01-01

, strikingly overlapping a network previously shown to be involved in recall of spatial aspects of images depicting similar scenarios. This supports a neurocognitive model of language function, where sentences establish meaning by interacting with the perceptual and working memory networks of the brain.......Abstract: The ‘‘overlapping systems'' theory of language function argues that linguistic meaning construction crucially relies on contextual information provided by ‘‘nonlinguistic'' cognitive systems, such as perception and memory. This study examines whether linguistic processing of spatial.......g., ‘‘Was he turned towards her?'') and equally concrete nonspatial content (e.g., ‘‘Was he older than her?''). We found that recall of the spatial content relative to the nonspatial content resulted in higher BOLD response in a dorsoposterior network of brain regions, most significantly in precuneus...

Spatial mismatch, wages and unemployment in metropolitan areas in Brazil

Directory of Open Access Journals (Sweden)

Ana Maria Bonomi Barufi

2017-12-01

Full Text Available The spatial mismatch hypothesis states that a lack of connection to job opportunities may affect an individual’s prospects in the labour market, especially for low-skilled workers. This phenomenon is especially observed in large urban areas, in which low-skilled minorities tend to live far away from jobs and face geographical barriers to finding and keeping jobs. This paper aims to investigate whether this negative relationship between spatial mismatch and labour market outcomes is valid in Brazil after controlling for individual characteristics. Our conclusions indicate that there is no clear relation between different measures of accessibility to jobs and the probability of being unemployed. However, for wages there is a clear correlation, which is stronger in larger metropolitan areas in the country. Given the exploratory nature of this work, our results still rely on strong identification hypotheses to avoid potential bias related to simultaneous location decisions of workers and firms within the city. Even if these conditions do not hold, the results are still meaningful as they provide a better understanding of the conditional distribution of wages and the unemployment rate in the biggest metropolitan areas of Brazil.

An event-related potential study on the interaction between lighting level and stimulus spatial location

Directory of Open Access Journals (Sweden)

Luis eCarretié

2015-11-01

Full Text Available Due to heterogeneous photoreceptor distribution, spatial location of stimulation is crucial to study visual brain activity in different light environments. This unexplored issue was studied through occipital event-related potentials (ERPs recorded from 40 participants in response to discrete visual stimuli presented at different locations and in two environmental light conditions, low mesopic (L, 0.03 lux and high mesopic (H, 6.5 lux, characterized by a differential photoreceptor activity balance: rod>cone and rodspatial location of stimulation: differences were greater in response to peripheral stimuli than to stimuli presented at fixation. Moreover, in the former case, significance of L vs. H differences was even stronger in response to stimuli presented at the horizontal than at the vertical periphery. These low vs. high mesopic differences may be explained by photoreceptor activation and their retinal distribution, and confirm that ERPs discriminate between rod- and cone-originated visual processing.

Assessment of Rainfall-induced Landslide Potential and Spatial Distribution

Science.gov (United States)

Chen, Yie-Ruey; Tsai, Kuang-Jung; Chen, Jing-Wen; Chiang, Jie-Lun; Hsieh, Shun-Chieh; Chue, Yung-Sheng

2016-04-01

Recently, due to the global climate change, most of the time the rainfall in Taiwan is of short duration but with high intensity. Due to Taiwan's steep terrain, rainfall-induced landslides often occur and lead to human causalities and properties loss. Taiwan's government has invested huge reconstruction funds to the affected areas. However, after rehabilitation they still face the risk of secondary sediment disasters. Therefore, this study assesses rainfall-induced (secondary) landslide potential and spatial distribution in watershed of Southern Taiwan under extreme climate change. The study areas in this research are Baolai and Jianshan villages in the watershed of the Laonongxi River Basin in the Southern Taiwan. This study focused on the 3 years after Typhoon Morakot (2009 to 2011). During this period, the study area experienced six heavy rainfall events including five typhoons and one heavy rainfall. The genetic adaptive neural network, texture analysis and GIS were implemented in the analysis techniques for the interpretation of satellite images and to obtain surface information and hazard log data and to analyze land use change. A multivariate hazards evaluation method was applied to quantitatively analyze the weights of various natural environmental and slope development hazard factors. Furthermore, this study established a slope landslide potential assessment model and depicted a slope landslide potential diagram by using the GIS platform. The interaction between (secondary) landslide mechanism, scale, and location was analyzed using association analysis of landslide historical data and regional environmental characteristics. The results of image classification before and after six heavy rainfall events show that the values of coefficient of agreement are at medium-high level. By multivariate hazards evaluation method, geology and the effective accumulative rainfall (EAR) are the most important factors. Slope, distance from fault, aspect, land disturbance

Are HPV vaccination services accessible to high-risk communities? A spatial analysis of HPV-associated cancer and Chlamydia rates and safety-net clinics.

Science.gov (United States)

Tsui, Jennifer; Rodriguez, Hector P; Gee, Gilbert C; Escobedo, Loraine A; Kominski, Gerald F; Bastani, Roshan

2013-12-01

While HPV vaccines can greatly benefit adolescents and young women from high-risk areas, little is known about whether safety-net immunization services are geographically accessible to communities at greatest risk for HPV-associated diseases. We explore the spatial relationship between areas with high HPV risk and proximity to safety-net clinics from an ecologic perspective. We used cancer registry data and Chlamydia surveillance data to identify neighborhoods within Los Angeles County with high risk for HPV-associated cancers. We examined proximity to safety-net clinics among neighborhoods with the highest risk. Proximity was measured as the shortest distance between each neighborhood center and the nearest clinic and having a clinic within 3 miles of each neighborhood center. The average 5-year non-age-adjusted rates were 1,940 cases per 100,000 for Chlamydia and 60 per 100,000 for HPV-associated cancers. A large majority, 349 of 386 neighborhoods with high HPV-associated cancer rates and 532 of 537 neighborhoods with high Chlamydia rates, had a clinic within 3 miles of the neighborhood center. Clinics were more likely to be located within close proximity to high-risk neighborhoods in the inner city. High-risk neighborhoods outside of this urban core area were less likely to be near accessible clinics. The majority of high-risk neighborhoods were geographically near safety-net clinics with HPV vaccination services. Due to low rates of vaccination, these findings suggest that while services are geographically accessible, additional efforts are needed to improve uptake. Programs aimed to increase awareness about the vaccine and to link underserved groups to vaccination services are warranted.

Accessing High Spatial Resolution in Astronomy Using Interference Methods

Science.gov (United States)

Carbonel, Cyril; Grasset, Sébastien; Maysonnave, Jean

2018-04-01

In astronomy, methods such as direct imaging or interferometry-based techniques (Michelson stellar interferometry for example) are used for observations. A particular advantage of interferometry is that it permits greater spatial resolution compared to direct imaging with a single telescope, which is limited by diffraction owing to the aperture of the instrument as shown by Rueckner et al. in a lecture demonstration. The focus of this paper, addressed to teachers and/or students in high schools and universities, is to easily underline both an application of interferometry in astronomy and stress its interest for resolution. To this end very simple optical experiments are presented to explain all the concepts. We show how an interference pattern resulting from the combined signals of two telescopes allows us to measure the distance between two stars with a resolution beyond the diffraction limit. Finally this work emphasizes the breathtaking resolution obtained in state-of-the-art instruments such as the VLTi (Very Large Telescope interferometer).

The influence of caffeine on spatial-selective attention : an event-related potential study

NARCIS (Netherlands)

de Ruiter, MB; Snel, J; Lorist, MM; Ruijter, J

2000-01-01

Objectives: Following the indications of previous studies that caffeine might have a specific effect on the processing of spatial information compared with other types of information, the present study investigated the influence of caffeine on an often used spatial-selective attention task. Methods:

The “SAFARI” Technique Using Retrograde Access Via Peroneal Artery Access

International Nuclear Information System (INIS)

Zhuang, Kun Da; Tan, Seck Guan; Tay, Kiang Hiong

2012-01-01

The “SAFARI” technique or subintimal arterial flossing with antegrade–retrograde intervention is a method for recanalisation of chronic total occlusions (CTOs) when subintimal angioplasty fails. Retrograde access is usually obtained via the popliteal, distal anterior tibial artery (ATA)/dorsalis pedis (DP), or distal posterior tibial artery (PTA). Distal access via the peroneal artery has not been described and has a risk of continued bleeding, leading to compartment syndrome due to its deep location. We describe our experience in two patients with retrograde access via the peroneal artery and the use of balloon-assisted hemostasis for these retrograde punctures. This approach may potentially give more options for endovascular interventions in lower limb CTOs.

Generalized index for spatial data sets as a measure of complete spatial randomness

Science.gov (United States)

Hackett-Jones, Emily J.; Davies, Kale J.; Binder, Benjamin J.; Landman, Kerry A.

2012-06-01

Spatial data sets, generated from a wide range of physical systems can be analyzed by counting the number of objects in a set of bins. Previous work has been limited to equal-sized bins, which are inappropriate for some domains (e.g., circular). We consider a nonequal size bin configuration whereby overlapping or nonoverlapping bins cover the domain. A generalized index, defined in terms of a variance between bin counts, is developed to indicate whether or not a spatial data set, generated from exclusion or nonexclusion processes, is at the complete spatial randomness (CSR) state. Limiting values of the index are determined. Using examples, we investigate trends in the generalized index as a function of density and compare the results with those using equal size bins. The smallest bin size must be much larger than the mean size of the objects. We can determine whether a spatial data set is at the CSR state or not by comparing the values of a generalized index for different bin configurations—the values will be approximately the same if the data is at the CSR state, while the values will differ if the data set is not at the CSR state. In general, the generalized index is lower than the limiting value of the index, since objects do not have access to the entire region due to blocking by other objects. These methods are applied to two applications: (i) spatial data sets generated from a cellular automata model of cell aggregation in the enteric nervous system and (ii) a known plant data distribution.

Discovery of accessible locations using region-based geo-social data

KAUST Repository

Wang, Yan; Li, Jianmin; Zhong, Ying; Zhu, Shunzhi; Guo, Danhuai; Shang, Shuo

2018-01-01

Geo-social data plays a significant role in location discovery and recommendation. In this light, we propose and study a novel problem of discovering accessible locations in spatial networks using region-based geo-social data. Given a set Q of query

Development and Application of an Activity Based Space-Time Accessibility Measure for Individual Activity Schedules

OpenAIRE

Olu Ashiru; John Polak; Robert B. Noland

2003-01-01

Accessibility is an important aspect of human existence impacting on our notion of society equity and justice. It plays an important role in a number of existing theories of spatial and travel behaviour in addition to affecting the rate and the pattern of land-use development. However despite the importance of the notion of accessibility, the accessibility measures, which have traditionally been used to quantify accessibility, have tended to be relatively poorly defined, excluding a wide rang...

A model for optimizing file access patterns using spatio-temporal parallelism

Energy Technology Data Exchange (ETDEWEB)

Boonthanome, Nouanesengsy [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Patchett, John [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Geveci, Berk [Kitware Inc., Clifton Park, NY (United States); Ahrens, James [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Bauer, Andy [Kitware Inc., Clifton Park, NY (United States); Chaudhary, Aashish [Kitware Inc., Clifton Park, NY (United States); Miller, Ross G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Shipman, Galen M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Williams, Dean N. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2013-01-01

For many years now, I/O read time has been recognized as the primary bottleneck for parallel visualization and analysis of large-scale data. In this paper, we introduce a model that can estimate the read time for a file stored in a parallel filesystem when given the file access pattern. Read times ultimately depend on how the file is stored and the access pattern used to read the file. The file access pattern will be dictated by the type of parallel decomposition used. We employ spatio-temporal parallelism, which combines both spatial and temporal parallelism, to provide greater flexibility to possible file access patterns. Using our model, we were able to configure the spatio-temporal parallelism to design optimized read access patterns that resulted in a speedup factor of approximately 400 over traditional file access patterns.

The role of gestures in spatial working memory and speech.

Science.gov (United States)

Morsella, Ezequiel; Krauss, Robert M

2004-01-01

Co-speech gestures traditionally have been considered communicative, but they may also serve other functions. For example, hand-arm movements seem to facilitate both spatial working memory and speech production. It has been proposed that gestures facilitate speech indirectly by sustaining spatial representations in working memory. Alternatively, gestures may affect speech production directly by activating embodied semantic representations involved in lexical search. Consistent with the first hypothesis, we found participants gestured more when describing visual objects from memory and when describing objects that were difficult to remember and encode verbally. However, they also gestured when describing a visually accessible object, and gesture restriction produced dysfluent speech even when spatial memory was untaxed, suggesting that gestures can directly affect both spatial memory and lexical retrieval.

Potential for spatial displacement of Cook Inlet beluga whales by anthropogenic noise in critical habitat

Science.gov (United States)

Small, Robert J.; Brost, Brian M.; Hooten, Mevin B.; Castellote, Manuel; Mondragon, Jeffrey

2017-01-01

The population of beluga whales in Cook Inlet, Alaska, USA, declined by nearly half in the mid-1990s, primarily from an unsustainable harvest, and was listed as endangered in 2008. In 2014, abundance was ~340 whales, and the population trend during 1999-2014 was -1.3% yr-1. Cook Inlet beluga whales are particularly vulnerable to anthropogenic impacts, and noise that has the potential to reduce communication and echolocation range considerably has been documented in critical habitat; thus, noise was ranked as a high potential threat in the Cook Inlet beluga Recovery Plan. The current recovery strategy includes research on effects of threats potentially limiting recovery, and thus we examined the potential impact of anthropogenic noise in critical habitat, specifically, spatial displacement. Using a subset of data on anthropogenic noise and beluga detections from a 5 yr acoustic study, we evaluated the influence of noise events on beluga occupancy probability. We used occupancy models, which account for factors that affect detection probability when estimating occupancy, the first application of these models to examine the potential impacts of anthropogenic noise on marine mammal behavior. Results were inconclusive, primarily because beluga detections were relatively infrequent. Even though noise metrics (sound pressure level and noise duration) appeared in high-ranking models as covariates for occupancy probability, the data were insufficient to indicate better predictive ability beyond those models that only included environmental covariates. Future studies that implement protocols designed specifically for beluga occupancy will be most effective for accurately estimating the effect of noise on beluga displacement.

A Multi-view Framework to Assess Spatial Data Infrastructures

NARCIS (Netherlands)

Crompvoets, J.W.H.C.; Rajabifard, A.; Loenen, van B.; Delgado Fernandez, T.

2008-01-01

There is growing interest internationally in the role that Spatial Data Infrastructures SDIs play as key tools in supporting sustainable development. SDIs, as defined in the context of this book, are network-based national solutions to provide easy, consistent and effective access to geographic

The effects of CCK-8S on spatial memory and long-term potentiation at CA1 during induction of stress in rats

Directory of Open Access Journals (Sweden)

Malihe Sadeghi

2017-12-01

Full Text Available Objective(s: Cholecystokinin (CCK has been proposed as a mediator in stress. However, it is still not fully documented what are its effects. We aimed to evaluate the effects of systemic administration of CCK exactly before induction of stress on spatial memory and synaptic plasticity at CA1 in rats. Materials and Methods: Male Wistar rats were divided into 4 groups: the control, the control-CCK, the stress and the stress-CCK. Restraint stress was induced 6 hr per day, for 24 days. Cholecystokinin sulfated octapeptide (CCK-8S was injected (1.6 µg/kg, IP before each session of stress induction. Spatial memory was evaluated by Morris water maze test. Long term potentiation (LTP in Schaffer collateral-CA1 synapses was assessed (by 100 Hz tetanization in order to investigate synaptic plasticity. Results: Stress impaired spatial memory significantly (P

Measuring sustainable accessibility potential using the mobility infrastructure's network configuration

NARCIS (Netherlands)

Gil, J.; Read, S.

2012-01-01

This paper is an exploration into the analysis of public transport networks using space syntax approaches combined with concepts of sustainable accessibility. Present urban development policy aims to achieve sustainable mobility patterns, shifting mobility to soft transportation modes such as

Elements of spatial data quality

CERN Document Server

Guptill, SC

1995-01-01

Elements of Spatial Data Quality outlines the need and suggests potential categories for the content of a comprehensive statement of data quality that must be imbedded in the metadata that accompanies the transfer of a digital spatial data file or is available in a separate metadata catalog. Members of the International Cartographic Association's Commission on Spatial Data Quality have identified seven elements of data quality: positional accuracy, attribute accuracy, completeness, logical consistency, lineage, semantic accuracy and temporal information. In the book the authors describe: compo

Measurement-Based Spatial Correlation and Capacity of Indoor Distributed MIMO System

Directory of Open Access Journals (Sweden)

Yan Zhang

2013-01-01

Full Text Available Distributed MIMO (D-MIMO system is one of the candidates for future wireless access networks. In this study, the spatial correlation and capacity in indoor D-MIMO system are presented. All results are from the actual channel measurements in typical indoor scenarios, including office and corridor. Based on measured data, spatial correlation coefficients between distributed transmitting antennas are analyzed. Although the literature about D-MIMO system assumes the small scale fading between distributed antennas is independent, we find that spatial correlation may still exist in specific propagation scenario. This correlation can also degrade the performance of D-MIMO system. To mitigate the impact of spatial correlation, one efficient method is to use transmitting antenna selection technique.

Accessing patient-centered care using the advanced access model.

Science.gov (United States)

Tantau, Catherine

2009-01-01

Waits and delays for healthcare are legendary. These delays are not only frustrating and potentially hazardous for patients and providers but also represent significant cost to office practices. The traditional medical model that defines urgent care versus routine care is a vain and futile attempt to sort demand. This approach is at constant odds with patients' definition of urgency. Trusting patients to determine when and how they want to access care makes sense from a customer service perspective. If approached systematically using the principles of Advanced Access, patient demand patterns can be tracked to forecast demand. These demand patterns become the template for deploying the resources necessary to meet patients' needs. Although not a simple journey, the transformation to Advanced Access provides an entree to patient-centered care where patients can say, "I get exactly the care I want and need, when I want and need it."

Addressing geographic access barriers to emergency care services: a national ecologic study of hospitals in Brazil.

Science.gov (United States)

Rocha, Thiago Augusto Hernandes; da Silva, Núbia Cristina; Amaral, Pedro Vasconcelos; Barbosa, Allan Claudius Queiroz; Rocha, João Victor Muniz; Alvares, Viviane; de Almeida, Dante Grapiuna; Thumé, Elaine; Thomaz, Erika Bárbara Abreu Fonseca; de Sousa Queiroz, Rejane Christine; de Souza, Marta Rovery; Lein, Adriana; Lopes, Daniel Paulino; Staton, Catherine A; Vissoci, João Ricardo Nickenig; Facchini, Luiz Augusto

2017-08-22

Unequal distribution of emergency care services is a critical barrier to be overcome to assure access to emergency and surgical care. Considering this context it was objective of the present work analyze geographic access barriers to emergency care services in Brazil. A secondary aim of the study is to define possible roles to be assumed by small hospitals in the Brazilian healthcare network to overcome geographic access challenges. The present work can be classified as a cross-sectional ecological study. To carry out the present study, data of all 5843 Brazilian hospitals were categorized among high complexity centers and small hospitals. The geographical access barriers were identified through the use of two-step floating catchment area method. Once concluded the previous step an evaluation using the Getis-Ord-Gi method was performed to identify spatial clusters of municipalities with limited access to high complexity centers but well covered by well-equipped small hospitals. The analysis of accessibility index of high complexity centers highlighted large portions of the country with nearly zero hospital beds by inhabitant. In contrast, it was possible observe a group of 1595 municipalities with high accessibility to small hospitals, simultaneously with a low coverage of high complexity centers. Among the 1595 municipalities with good accessibility to small hospitals, 74% (1183) were covered by small hospitals with at least 60% of minimum emergency service requirements. The spatial clusters analysis aggregated 589 municipalities with high values related to minimum emergency service requirements. Small hospitals in these 589 cities could promote the equity in access to emergency services benefiting more than eight million people. There is a spatial disequilibrium within the country with prominent gaps in the health care network for emergency services. Taking this challenge into consideration, small hospitals could be a possible solution and foster equity in access

Spatial price transmission and market integration of Cistanthera ...

African Journals Online (AJOL)

Spatial price transmission and market integration of Cistanthera papaverifera species in ... Log in or Register to get access to full text downloads. ... the null hypothesis of non-stationarity at their levels at 1% and 5% significance level. ... This study concludes that sawn-wood marketing in Delta State have a high degree of ...

Spatial income inequality in Brazil, 1872–2000

Directory of Open Access Journals (Sweden)

Eustáquio Reis

2014-05-01

Full Text Available The paper provides historical perspectives on spatial economic inequalities in Brazil making use of a database on Brazilian municipalities from 1872 to 2000. A suit of maps and graphs describe the geographic factors shaping the historical development of the Brazilian economy highlighting the role of transport costs and its consequences for the spatial dynamics of income per capita and labor productivity. The remaining of the paper estimates econometric models of growth convergence for municipal income per capita and labor productivity. From 1920 onwards analyses are refined, firstly, by disaggregating the models for urban and rural activities; secondly, by assuming spatial correlation among variables of the model; and, thirdly, by enlarging the model to take account of the long run determinants of spatial growth convergence. Empirical results endorse the historical preeminence of geographic factors – in particular accessibility and transport conditions – as opposed to institutional conditions. The conclusion summarizes the results and proposes research extensions.

Smart Cities Intelligence System (SMACiSYS) Integrating Sensor Web with Spatial Data Infrastructures (sensdi)

Science.gov (United States)

Bhattacharya, D.; Painho, M.

2017-09-01

The paper endeavours to enhance the Sensor Web with crucial geospatial analysis capabilities through integration with Spatial Data Infrastructure. The objective is development of automated smart cities intelligence system (SMACiSYS) with sensor-web access (SENSDI) utilizing geomatics for sustainable societies. There has been a need to develop automated integrated system to categorize events and issue information that reaches users directly. At present, no web-enabled information system exists which can disseminate messages after events evaluation in real time. Research work formalizes a notion of an integrated, independent, generalized, and automated geo-event analysing system making use of geo-spatial data under popular usage platform. Integrating Sensor Web With Spatial Data Infrastructures (SENSDI) aims to extend SDIs with sensor web enablement, converging geospatial and built infrastructure, and implement test cases with sensor data and SDI. The other benefit, conversely, is the expansion of spatial data infrastructure to utilize sensor web, dynamically and in real time for smart applications that smarter cities demand nowadays. Hence, SENSDI augments existing smart cities platforms utilizing sensor web and spatial information achieved by coupling pairs of otherwise disjoint interfaces and APIs formulated by Open Geospatial Consortium (OGC) keeping entire platform open access and open source. SENSDI is based on Geonode, QGIS and Java, that bind most of the functionalities of Internet, sensor web and nowadays Internet of Things superseding Internet of Sensors as well. In a nutshell, the project delivers a generalized real-time accessible and analysable platform for sensing the environment and mapping the captured information for optimal decision-making and societal benefit.

SMART CITIES INTELLIGENCE SYSTEM (SMACiSYS INTEGRATING SENSOR WEB WITH SPATIAL DATA INFRASTRUCTURES (SENSDI

Directory of Open Access Journals (Sweden)

D. Bhattacharya

2017-09-01

Full Text Available The paper endeavours to enhance the Sensor Web with crucial geospatial analysis capabilities through integration with Spatial Data Infrastructure. The objective is development of automated smart cities intelligence system (SMACiSYS with sensor-web access (SENSDI utilizing geomatics for sustainable societies. There has been a need to develop automated integrated system to categorize events and issue information that reaches users directly. At present, no web-enabled information system exists which can disseminate messages after events evaluation in real time. Research work formalizes a notion of an integrated, independent, generalized, and automated geo-event analysing system making use of geo-spatial data under popular usage platform. Integrating Sensor Web With Spatial Data Infrastructures (SENSDI aims to extend SDIs with sensor web enablement, converging geospatial and built infrastructure, and implement test cases with sensor data and SDI. The other benefit, conversely, is the expansion of spatial data infrastructure to utilize sensor web, dynamically and in real time for smart applications that smarter cities demand nowadays. Hence, SENSDI augments existing smart cities platforms utilizing sensor web and spatial information achieved by coupling pairs of otherwise disjoint interfaces and APIs formulated by Open Geospatial Consortium (OGC keeping entire platform open access and open source. SENSDI is based on Geonode, QGIS and Java, that bind most of the functionalities of Internet, sensor web and nowadays Internet of Things superseding Internet of Sensors as well. In a nutshell, the project delivers a generalized real-time accessible and analysable platform for sensing the environment and mapping the captured information for optimal decision-making and societal benefit.

Interactive, open source, travel time scenario modelling: tools to facilitate participation in health service access analysis.

Science.gov (United States)

Fisher, Rohan; Lassa, Jonatan

2017-04-18

Modelling travel time to services has become a common public health tool for planning service provision but the usefulness of these analyses is constrained by the availability of accurate input data and limitations inherent in the assumptions and parameterisation. This is particularly an issue in the developing world where access to basic data is limited and travel is often complex and multi-modal. Improving the accuracy and relevance in this context requires greater accessibility to, and flexibility in, travel time modelling tools to facilitate the incorporation of local knowledge and the rapid exploration of multiple travel scenarios. The aim of this work was to develop simple open source, adaptable, interactive travel time modelling tools to allow greater access to and participation in service access analysis. Described are three interconnected applications designed to reduce some of the barriers to the more wide-spread use of GIS analysis of service access and allow for complex spatial and temporal variations in service availability. These applications are an open source GIS tool-kit and two geo-simulation models. The development of these tools was guided by health service issues from a developing world context but they present a general approach to enabling greater access to and flexibility in health access modelling. The tools demonstrate a method that substantially simplifies the process for conducting travel time assessments and demonstrate a dynamic, interactive approach in an open source GIS format. In addition this paper provides examples from empirical experience where these tools have informed better policy and planning. Travel and health service access is complex and cannot be reduced to a few static modeled outputs. The approaches described in this paper use a unique set of tools to explore this complexity, promote discussion and build understanding with the goal of producing better planning outcomes. The accessible, flexible, interactive and

Food environments and dietary intakes among adults: does the type of spatial exposure measurement matter? A systematic review.

Science.gov (United States)

Bivoltsis, Alexia; Cervigni, Eleanor; Trapp, Gina; Knuiman, Matthew; Hooper, Paula; Ambrosini, Gina Leslie

2018-06-09

The relationships between food environments and dietary intake have been assessed via a range of methodologically diverse measures of spatial exposure to food outlets, resulting in a largely inconclusive body of evidence, limiting informed policy intervention. This systematic review aims to evaluate the influence of methodological choice on study outcomes by examining the within-study effect of availability (e.g., counts) versus accessibility (e.g., proximity) spatial exposure measures on associations with diet. (PROSPERO registration: CRD42018085250). PubMed, Web of Science, Scopus and ScienceDirect databases were searched for empirical studies from 1980 to 2017, in the English language, involving adults and reporting on the statistical association between a dietary outcome and spatial exposure measures of both availability and accessibility. Studies were appraised using an eight-point quality criteria with a narrative synthesis of results. A total of 205 associations and 44 relationships (i.e., multiple measures of spatial exposure relating to a particular food outlet type and dietary outcome) were extracted from 14 eligible articles. Comparative measures were dominated by counts (availability) and proximity (accessibility). Few studies compared more complex measures and all counts were derived from place-based measures of exposure. Sixteen of the 44 relationships had a significant effect involving an availability measure whilst only 8 had a significant effect from an accessibility measure. The largest effect sizes in relationships were mostly for availability measures. After stratification by scale, availability measure had the greatest effect size in 139 of the 176 pairwise comparisons. Of the 33% (68/205) of associations that reached significance, 53/68 (78%) were from availability measures. There was no relationship between study quality and reported study outcomes. The limited evidence suggests that availability measures may produce significant and greater

High-speed, random-access fluorescence microscopy: I. High-resolution optical recording with voltage-sensitive dyes and ion indicators.

Science.gov (United States)

Bullen, A; Patel, S S; Saggau, P

1997-07-01

The design and implementation of a high-speed, random-access, laser-scanning fluorescence microscope configured to record fast physiological signals from small neuronal structures with high spatiotemporal resolution is presented. The laser-scanning capability of this nonimaging microscope is provided by two orthogonal acousto-optic deflectors under computer control. Each scanning point can be randomly accessed and has a positioning time of 3-5 microseconds. Sampling time is also computer-controlled and can be varied to maximize the signal-to-noise ratio. Acquisition rates up to 200k samples/s at 16-bit digitizing resolution are possible. The spatial resolution of this instrument is determined by the minimal spot size at the level of the preparation (i.e., 2-7 microns). Scanning points are selected interactively from a reference image collected with differential interference contrast optics and a video camera. Frame rates up to 5 kHz are easily attainable. Intrinsic variations in laser light intensity and scanning spot brightness are overcome by an on-line signal-processing scheme. Representative records obtained with this instrument by using voltage-sensitive dyes and calcium indicators demonstrate the ability to make fast, high-fidelity measurements of membrane potential and intracellular calcium at high spatial resolution (2 microns) without any temporal averaging.

AN ANALYSIS OF SPATIAL EQUITY CONCERNING INVESTMENTS IN HIGH-SPEED RAIL SYSTEMS: THE CASE STUDY OF ITALY

Directory of Open Access Journals (Sweden)

Francesca PAGLIARA

2016-09-01

Full Text Available It is recognised in the literature that spatial accessibility is a measure of spatial equity and can be represented by the ease of travelling from an origin to a given destination via a given mode or set of transport modes. Although urban areas can benefit from improvements in accessibility when a new high-speed rail line is built, equity issues may arise. This manuscript describes a methodology for evaluating equity impacts due to an extension of the High Speed Rail network in Italy. A joint Revealed/Stated Preference survey has been carried out, collecting socioeconomic and travel data. Specifically, nine hypothetical scenarios have been submitted to Italian users aiming at understanding the motivations for not choosing the High Speed Rail as an alternative. The main outcome is that the access/egress travel costs connected with the High Speed Rail have a strong impact on spatial equity. The main policy implications of this study are that investors in high-speed rail should not only take into account the economic benefits brought by them, but also the spatial imbalance that these systems can bring.

The Helioviewer Project: Browsing, Visualizing and Accessing Petabytes of Solar Data

Science.gov (United States)

Mueller, Daniel; Hughitt, V. K.; Langenberg, M.; Ireland, J.; Pagel, S.; Schmidt, L.; Garcia Ortiz, J. P.; Dimitoglou, G.; Fleck, B.

2010-05-01

After its successful launch, NASA's Solar Dynamics Observatory (SDO) will soon return more than 1 Terabyte worth of images per day. This unprecedented torrent of data will pose an entirely new set of challenges with respect to data access, data browsing and searching for interesting data while avoiding the proverbial search for "a needle in a haystack". In order to fully exploit SDO's wealth of data and connect it to data from other solar missions like SOHO, scientists need to be able to interactively browse and visualize many different data products spanning a large range of physical length and time scales. So far, all tools available to the scientific community either require downloading all potentially relevant data sets beforehand in their entirety or provide only movies with a fixed resolution and cadence. The Helioviewer project offers a solution to these challenges by providing a suite of tools that are based on the new JPEG 2000 compression standard and enable scientists and the general public alike to intuitively browse visualize and access petabytes of image data remotely: - JHelioviewer, a cross-platform application that offers movie streaming and real-time processing using the JPEG 2000 Interactive Protocol (JPIP) and OpenGL, as well as feature/event overlays. - helioviewer.org, a web-based image and feature/event browser. - Server-side services to stream movies of arbitrary spatial and temporal resolution in a region-of-interest and quality-progressive form, a JPEG 2000 image database and a feature/event server. All the services can be accessed through well-documented interfaces (APIs). - Code to convert images into JPEG 2000 format. This presentation will give an overview of the Helioviewer Project, illustrate new features and highlight the advantages of JPEG 2000 as a data format for solar physics that has the potential to revolutionize the way high-resolution image data are disseminated and analyzed.

The 'SAFARI' Technique Using Retrograde Access Via Peroneal Artery Access

Energy Technology Data Exchange (ETDEWEB)

Zhuang, Kun Da, E-mail: zkunda@gmail.com [Singapore General Hospital, Interventional Radiology Centre (Singapore); Tan, Seck Guan [Singapore General Hospital, Department of General Surgery (Singapore); Tay, Kiang Hiong [Singapore General Hospital, Interventional Radiology Centre (Singapore)

2012-08-15

The 'SAFARI' technique or subintimal arterial flossing with antegrade-retrograde intervention is a method for recanalisation of chronic total occlusions (CTOs) when subintimal angioplasty fails. Retrograde access is usually obtained via the popliteal, distal anterior tibial artery (ATA)/dorsalis pedis (DP), or distal posterior tibial artery (PTA). Distal access via the peroneal artery has not been described and has a risk of continued bleeding, leading to compartment syndrome due to its deep location. We describe our experience in two patients with retrograde access via the peroneal artery and the use of balloon-assisted hemostasis for these retrograde punctures. This approach may potentially give more options for endovascular interventions in lower limb CTOs.

Spatial navigation by congenitally blind individuals.

Science.gov (United States)

Schinazi, Victor R; Thrash, Tyler; Chebat, Daniel-Robert

2016-01-01

Spatial navigation in the absence of vision has been investigated from a variety of perspectives and disciplines. These different approaches have progressed our understanding of spatial knowledge acquisition by blind individuals, including their abilities, strategies, and corresponding mental representations. In this review, we propose a framework for investigating differences in spatial knowledge acquisition by blind and sighted people consisting of three longitudinal models (i.e., convergent, cumulative, and persistent). Recent advances in neuroscience and technological devices have provided novel insights into the different neural mechanisms underlying spatial navigation by blind and sighted people and the potential for functional reorganization. Despite these advances, there is still a lack of consensus regarding the extent to which locomotion and wayfinding depend on amodal spatial representations. This challenge largely stems from methodological limitations such as heterogeneity in the blind population and terminological ambiguity related to the concept of cognitive maps. Coupled with an over-reliance on potential technological solutions, the field has diffused into theoretical and applied branches that do not always communicate. Here, we review research on navigation by congenitally blind individuals with an emphasis on behavioral and neuroscientific evidence, as well as the potential of technological assistance. Throughout the article, we emphasize the need to disentangle strategy choice and performance when discussing the navigation abilities of the blind population. For further resources related to this article, please visit the WIREs website. © 2015 The Authors. WIREs Cognitive Science published by Wiley Periodicals, Inc.

Variation in low food access areas due to data source inaccuracies

OpenAIRE

Ma, Xiaoguang; Battersby, Sarah E.; Bell, Bethany A.; Hibbert, James D.; Barnes, Timothy L.; Liese, Angela D.

2013-01-01

Several spatial measures of community food access identifying so called “food deserts” have been developed based on geospatial information and commercially-available, secondary data listings of food retail outlets. It is not known how data inaccuracies influence the designation of Census tracts as areas of low access. This study replicated the U.S. Department of Agriculture Economic Research Service (USDA ERS) food desert measure and the Centers for Disease Control and Prevention (CDC) non-he...

Accessibility of GI for Public Participation

DEFF Research Database (Denmark)

Arleth, Mette; Campagna, Michele

2005-01-01

The paper reports an ongoing comparative study on the accessibility of Geographic Information at public authorities’ websites in Denmark and Italy. The purpose of the study is twofold; to give an idea of the latest development and diffusion of GI on public authorities websites, and to identify...... critical factors for success or failure of the applications. First part of the study therefore consists of a mapping of the level of accessibility of GI in the two countries as a comparative analysis. The focus of the mapping is mainly on the use of geographic information as support to citizens......’ involvement in spatial e-government and planning processes. Then, in the reminder of the paper, a comparative analysis is proposed outlining similarities and divergences in critical success factors in the two examined domains....

Individual Differences in Verbal and Spatial Stroop Tasks: Interactive Role of Handedness and Domain

Directory of Open Access Journals (Sweden)

Mariagrazia Capizzi

2017-11-01

Full Text Available A longstanding debate in psychology concerns the relation between handedness and cognitive functioning. The present study aimed to contribute to this debate by comparing performance of right- and non-right-handers on verbal and spatial Stroop tasks. Previous studies have shown that non-right-handers have better inter-hemispheric interaction and greater access to right hemisphere processes. On this ground, we expected performance of right- and non-right-handers to differ on verbal and spatial Stroop tasks. Specifically, relative to right-handers, non-right-handers should have greater Stroop effect in the color-word Stroop task, for which inter-hemispheric interaction does not seem to be advantageous to performance. By contrast, non-right-handers should be better able to overcome interference in the spatial Stroop task. This is for their preferential access to the right hemisphere dealing with spatial material and their greater inter-hemispheric interaction with the left hemisphere hosting Stroop task processes. Our results confirmed these predictions, showing that handedness and the underlying brain asymmetries may be a useful variable to partly explain individual differences in executive functions.

An investigation of student understanding of classical ideas related to quantum mechanics: Potential energy diagrams and spatial probability density

Science.gov (United States)

Stephanik, Brian Michael

This dissertation describes the results of two related investigations into introductory student understanding of ideas from classical physics that are key elements of quantum mechanics. One investigation probes the extent to which students are able to interpret and apply potential energy diagrams (i.e., graphs of potential energy versus position). The other probes the extent to which students are able to reason classically about probability and spatial probability density. The results of these investigations revealed significant conceptual and reasoning difficulties that students encounter with these topics. The findings guided the design of instructional materials to address the major problems. Results from post-instructional assessments are presented that illustrate the impact of the curricula on student learning.

Housing Accessibility Methodology Targeting Older People

DEFF Research Database (Denmark)

Helle, Tina

accessibility problems before the planning of housing intervention strategies. It is also critical that housing standards addressing accessibility intended to accommodate people with functional limitations are valid in the sense that their definitions truly support accessibility. However, there is a paucity...... of valid and reliable assessment instruments targeting housing accessibility, and in-depth analysis of factors potentially impacting on reliability in complex assessment situations is remarkably absent. Moreover, the knowledge base informing the housing standards appears to be vague. We may therefore...... reasonably question the validity of the housing standards addressing accessibility. This thesis addresses housing accessibility methodology in general and the reliability of assessment and the validity of standards targeting older people with functional limitations and a dependence on mobility devices...

Efficient Information Access for Location-Based Services in Mobile Environments

Science.gov (United States)

Lee, Chi Keung

2009-01-01

The demand for pervasive access of location-related information (e.g., local traffic, restaurant locations, navigation maps, weather conditions, pollution index, etc.) fosters a tremendous application base of "Location Based Services (LBSs)". Without loss of generality, we model location-related information as "spatial objects" and the accesses…

La carte axiale, un outil d'analyse de l'accessibilité spatiale : cas de ...

African Journals Online (AJOL)

PC Dounia

Among the developments of the method of Space Syntax, the axial map and its analysis of spatial accessibility ... grandes lignées en matière d'analyse ,une approche qui se dit normative et une autre d'ordre cognitive. ...... The theory of the city as object or how spatial laws mediate the social construction of urban space.

The Role of NASA's Planetary Data System in the Planetary Spatial Data Infrastructure Initiative

Science.gov (United States)

Arvidson, R. E.; Gaddis, L. R.

2017-12-01

An effort underway in NASA's planetary science community is the Mapping and Planetary Spatial Infrastructure Team (MAPSIT, http://www.lpi.usra.edu/mapsit/). MAPSIT is a community assessment group organized to address a lack of strategic spatial data planning for space science and exploration. Working with MAPSIT, a new initiative of NASA and USGS is the development of a Planetary Spatial Data Infrastructure (PSDI) that builds on extensive knowledge on storing, accessing, and working with terrestrial spatial data. PSDI is a knowledge and technology framework that enables the efficient discovery, access, and exploitation of planetary spatial data to facilitate data analysis, knowledge synthesis, and decision-making. NASA's Planetary Data System (PDS) archives >1.2 petabytes of digital data resulting from decades of planetary exploration and research. The PDS charter focuses on the efficient collection, archiving, and accessibility of these data. The PDS emphasis on data preservation and archiving is complementary to that of the PSDI initiative because the latter utilizes and extends available data to address user needs in the areas of emerging technologies, rapid development of tailored delivery systems, and development of online collaborative research environments. The PDS plays an essential PSDI role because it provides expertise to help NASA missions and other data providers to organize and document their planetary data, to collect and maintain the archives with complete, well-documented and peer-reviewed planetary data, to make planetary data accessible by providing online data delivery tools and search services, and ultimately to ensure the long-term preservation and usability of planetary data. The current PDS4 information model extends and expands PDS metadata and relationships between and among elements of the collections. The PDS supports data delivery through several node services, including the Planetary Image Atlas (https

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

Science.gov (United States)

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.

Effective monopole potential for SU(2) lattice gluodynamics in spatial maximal Abelian gauge

International Nuclear Information System (INIS)

Chernodub, M.N.; Polikarpov, M.I.; Veselov, A.I.

1999-01-01

We investigate the dual superconductor hypothesis in finite-temperature SU(2) lattice gluodynamics in the Spatial Maximal Abelian gauge. This gauge is more physical than the ordinary Maximal Abelian gauge due to absence of non-localities in temporal direction. We shown numerically that in the Spatial Maximal Abelian gauge the probability distribution of the abelian monopole field is consistent with the dual superconductor mechanism of confinement [ru

Spatial assessment of potential ecological risk of heavy metals in soils from informal e-waste recycling in Ghana

Directory of Open Access Journals (Sweden)

Vincent Nartey Kyere

2017-10-01

Full Text Available The rapidly increasing annual global volume of e-waste, and of its inherently valuable fraction, has created an opportunity for individuals in Agbogbloshie, Accra, Ghana to make a living by using unconventional, uncontrolled, primitive and crude procedures to recycle and recover valuable metals from this waste. The current form of recycling procedures releases hazardous fractions, such as heavy metals, into the soil, posing a significant risk to the environment and human health. Using a handheld global positioning system, 132 soil samples based on 100 m grid intervals were collected and analysed for cadmium (Cd, chromium (Cr, copper (Cu, mercury (Hg, lead (Pb and zinc (Zn. Using geostatistical techniques and sediment quality guidelines, this research seeks to assess the potential risk these heavy metals posed to the proposed Korle Ecological Restoration Zone by informal e-waste processing site in Agbogbloshie, Accra, Ghana. Analysis of heavy metals revealed concentrations exceeded the regulatory limits of both Dutch and Canadian soil quality and guidance values, and that the ecological risk posed by the heavy metals extended beyond the main burning and dismantling sites of the informal recyclers to the school, residential, recreational, clinic, farm and worship areas. The heavy metals Cr, Cu, Pb and Zn had normal distribution, spatial variability, and spatial autocorrelation. Further analysis revealed the decreasing order of toxicity, Hg>Cd>Pb> Cu>Zn>Cr, of contributing significantly to the potential ecological risk in the study area.

Decentralization, healthcare access, and inequality in Mpumalanga, South Africa.

Science.gov (United States)

Winchester, Margaret S; King, Brian

2018-04-27

Healthcare access and utilization remain key challenges in the Global South. South Africa represents this given that more than twenty years after the advent of democratic elections, the national government continues to confront historical systems of spatial manipulation that generated inequities in healthcare access. While the country has made significant advancements, governmental agencies have mirrored international strategies of healthcare decentralization and focused on local provision of primary care to increase healthcare access. In this paper, we show the significance of place in shaping access and health experiences for rural populations. Using data from a structured household survey, focus group discussions, qualitative interviews, and clinic data conducted in northeast South Africa from 2013 to 2016, we argue that decentralization fails to resolve the uneven landscapes of healthcare in the contemporary period. This is evidenced by the continued variability across the study area in terms of government-sponsored healthcare, and constraints in the clinics in terms of staffing, privacy, and patient loads, all of which challenge the access-related assumptions of healthcare decentralization. Copyright © 2018 Elsevier Ltd. All rights reserved.

Using multiscale spatial models to assess potential surrogate habitat for an imperiled reptile.

Directory of Open Access Journals (Sweden)

Jennifer M Fill

Full Text Available In evaluating conservation and management options for species, practitioners might consider surrogate habitats at multiple scales when estimating available habitat or modeling species' potential distributions based on suitable habitats, especially when native environments are rare. Species' dependence on surrogates likely increases as optimal habitat is degraded and lost due to anthropogenic landscape change, and thus surrogate habitats may be vital for an imperiled species' survival in highly modified landscapes. We used spatial habitat models to examine a potential surrogate habitat for an imperiled ambush predator (eastern diamondback rattlesnake, Crotalus adamanteus; EDB at two scales. The EDB is an apex predator indigenous to imperiled longleaf pine ecosystems (Pinus palustris of the southeastern United States. Loss of native open-canopy pine savannas and woodlands has been suggested as the principal cause of the species' extensive decline. We examined EDB habitat selection in the Coastal Plain tidewater region to evaluate the role of marsh as a potential surrogate habitat and to further quantify the species' habitat requirements at two scales: home range (HR and within the home range (WHR. We studied EDBs using radiotelemetry and employed an information-theoretic approach and logistic regression to model habitat selection as use vs.We failed to detect a positive association with marsh as a surrogate habitat at the HR scale; rather, EDBs exhibited significantly negative associations with all landscape patches except pine savanna. Within home range selection was characterized by a negative association with forest and a positive association with ground cover, which suggests that EDBs may use surrogate habitats of similar structure, including marsh, within their home ranges. While our HR analysis did not support tidal marsh as a surrogate habitat, marsh may still provide resources for EDBs at smaller scales.

Towards democracy in spatial planning through spatial information built by communities: The investigation of spatial information built by citizens from participatory mapping to volunteered geographic information in Indonesia

Science.gov (United States)

Yudono, Adipandang

2017-06-01

Recently, crowd-sourced information is used to produce and improve collective knowledge and community capacity building. Triggered by broadening and expanding access to the Internet and cellular telephones, the utilisation of crowd-sourcing for policy advocacy, e-government and e-participation has increased globally [1]. Crowd-sourced information can conceivably support government’s or general social initiatives to inform, counsel, and cooperate, by engaging subjects and empowering decentralisation and democratization [2]. Crowd-sourcing has turned into a major technique for interactive mapping initiatives by urban or rural community because of its capability to incorporate a wide range of data. Continuously accumulated spatial data can be sorted, layered, and envisioned in ways that even beginners can comprehend with ease. Interactive spatial visualization has the possibility to be a useful democratic planning tool to empower citizens participating in spatial data provision and sharing in government programmes. Since the global emergence of World Wide Web (WWW) technology, the interaction between information providers and users has increased. Local communities are able to produce and share spatial data to produce web interfaces with territorial information in mapping application programming interfaces (APIs) public, such as Google maps, OSM and Wikimapia [3][4][5]. In terms of the democratic spatial planning action, Volunteered Geographic Information (VGI) is considered an effective voluntary method of helping people feel comfortable with the technology and other co-participants in order to shape coalitions of local knowledge. This paper has aim to investigate ‘How is spatial data created by citizens used in Indonesia?’ by discussing the characteristics of spatial data usage by citizens to support spatial policy formulation, starting with the history of participatory mapping to current VGI development in Indonesia.

Open Access, Education Research, and Discovery

Science.gov (United States)

Furlough, Michael

2010-01-01

Background/Context: The open access movement has successfully drawn attention to economic and political aspects of scholarly communication through a significant body of commentary that debates the merits of open access and the potential damage it may do to scholarly publishing. Researchers within the field of education research, notably John…

Web Accessibility and Guidelines

Science.gov (United States)

Harper, Simon; Yesilada, Yeliz

Access to, and movement around, complex online environments, of which the World Wide Web (Web) is the most popular example, has long been considered an important and major issue in the Web design and usability field. The commonly used slang phrase ‘surfing the Web’ implies rapid and free access, pointing to its importance among designers and users alike. It has also been long established that this potentially complex and difficult access is further complicated, and becomes neither rapid nor free, if the user is disabled. There are millions of people who have disabilities that affect their use of the Web. Web accessibility aims to help these people to perceive, understand, navigate, and interact with, as well as contribute to, the Web, and thereby the society in general. This accessibility is, in part, facilitated by the Web Content Accessibility Guidelines (WCAG) currently moving from version one to two. These guidelines are intended to encourage designers to make sure their sites conform to specifications, and in that conformance enable the assistive technologies of disabled users to better interact with the page content. In this way, it was hoped that accessibility could be supported. While this is in part true, guidelines do not solve all problems and the new WCAG version two guidelines are surrounded by controversy and intrigue. This chapter aims to establish the published literature related to Web accessibility and Web accessibility guidelines, and discuss limitations of the current guidelines and future directions.

GSR-TDMA: A Geometric Spatial Reuse-Time Division Multiple Access MAC Protocol for Multihop Underwater Acoustic Sensor Networks

Directory of Open Access Journals (Sweden)

Changho Yun

2016-01-01

Full Text Available The nonnegligible propagation delay of acoustic signals causes spatiotemporal uncertainty that occasionally enables simultaneous, collision-free packet transmission among underwater nodes (UNs. These transmissions can be handled by efficiently managing the channel access of the UNs in the data-link layer. To this end, Geometric Spatial Reuse-TDMA (GSR-TDMA, a new TDMA-based MAC protocol, is designed for use in centralized, multihop underwater acoustic sensor networks (UASNs, and in this case all UNs are periodically scheduled after determining a geometric map according to the information on their location. The scheduling strategy increases the number of UNs that send packets coincidentally via two subscheduling configurations (i.e., interhop and intrahop scheduling. Extensive simulations are used to investigate the reception success rate (RSR and the multihop delay (MHD of GSR-TDMA, and the results are compared to those of previous approaches, including C-MAC and HSR-TDMA. GSR-TDMA outperforms C-MAC; the RSR of GSR-TDMA is 15% higher than that of C-MAC, and the MHD of GSR-TDMA is 30% lower than that of C-MAC at the most. In addition, GSR-TDMA provides even better performance improvements over HSR-TDMA; the RSR of GSR-TDMA is 50% higher than that of HSR-TDMA, and the MHD of GSR-TDMA is an order of 102 lower than that of HSR-TDMA at the most.

DETERMINATION OF AGRICULTURAL POTENTIAL BY GEO SPATIAL MODELING AND MULTI CRITERIA ANALYSIS FOR “BALSAS MEZCALA” WATERSHED

Directory of Open Access Journals (Sweden)

Anastacio Espejel-García

2015-07-01

Full Text Available The use of geographic information systems (GIS facilitates the modeling of specific information allowing faster, lower costs and accuracy for the planning of the agricultural activities for large territories. The objective for this paper was to use GIS as a support for the approach of the land use potential for the “Balsas Mezcala” watershed; for this purpose the multi criteria analysis was used, that allows to consider decision make issues with multiples objectives and considering the following criteria: geo-pedological (geomorphology and soil, climatology (thermal models and rainfall and the edapho-climatological requirements of the crops, the “Balsas Mezcala” hydrological region was chosen as the study area; through cartographic material the area was delimited and climate information was obtained from weather stations, geographic information and the data bases was collected from many different government agencies (INEGI, SEMARNAT, CONABIO, CONAGUA, IMTA, such information was processed in the ArcGIS software version 10.2.2, to obtained the geodatabases and geo spatial matrix which served as a cartographic input for the multi criteria analysis. The result of this investigation is a system that from geo spatial matrix and vectorial data originates raster dataset, same that were submitted to a modeling process with geo statistical algorithms, with that from a structure language, identify the potential zones with the highest aptness level, through the variable attributes that assign a weighted value using the methodology proposed by the United States Department of Agriculture (USDA in 1971 and taken by Food and Agriculture Organization of the United Nations (FAO for case studies since 1977 as an Agro-ecological Zoning System (AEZ. The result of the modeling of the soil aptness level in the watershed are 4 classes with 6 levels of aptness (very apt, apt, moderately apt, little apt, very little apt, unapt: Lands with irrigation potential

Spatial correlation of conductive filaments for multiple switching cycles in CBRAM

KAUST Repository

Pey, K. L.

2014-06-01

Conducting bridge random access memory (CBRAM) is one of the potential technologies being considered for replacement of Flash memory for non-volatile data storage. CBRAM devices operate on the principle of nucleation and rupture of metallic filaments. One key concern for commercializing this technology is the question of variability which could arise due to nucleation of multiple filaments across the device at spatially different locations. The spatial spread of the filament location may cause long tails at the low and high percentile regions for the switching parameter distribution as the new filament that nucleates may have a completely different shape and size. It is therefore essential to probe whether switching in CBRAM occurs every time at the same filament location or whether there are other new filaments that could nucleate during repeated cycling with some spatial correlation (if any) to the original filament. To investigate this issue, we make use of a metal-insulator-semiconductor (M-I-S) transistor test structure with Ni as the top electrode and HfOx/SiOx as the dielectric stack. In-situ stressing using a nano-tip on the M-I-S stack is performed and the filament is imaged in real-time using a high resolution transmission electron microscope (TEM). We also extract the location of the filament (LFIL) along the channel of the transistor after the nucleation stage using the weighted proportion of the source and drain currents. © 2014 IEEE.

Building-Based Analysis of the Spatial Provision of Urban Parks in Shenzhen, China

Directory of Open Access Journals (Sweden)

Wenxiu Gao

2017-12-01

Full Text Available Urban parks provide important environmental, social, and economic benefits to people and urban areas. The literature demonstrates that proximity to urban parks is one of the key factors influencing people’s willingness to use them. Therefore, the provision of urban parks near residential areas and workplaces is one of the key factors influencing quality of life. This study designed a solution based on the spatial association between urban parks and buildings where people live or work to identify whether people in different buildings have nearby urban parks available for their daily lives. A building density map based on building floor area (BFA was used to illustrate the spatial distribution of urban parks and five indices were designed to measure the scales, service coverage and potential service loads of urban parks and reveal areas lacking urban park services in an acceptable walking distance. With such solution, we investigated the provision of urban parks in ten districts of Shenzhen in China, which has grown from several small villages to a megacity in only 30 years. The results indicate that the spatial provision of urban parks in Shenzhen is not sufficient since people in about 65% of the buildings cannot access urban parks by walking 10-min. The distribution and service coverage of the existing urban parks is not balanced at the district level. In some districts, the existing urban parks have good numbers of potential users and even have large service loads, while in some districts, the building densities surrounding the existing parks are quite low and at the same time there is no urban parks nearby some high-density areas.

Building-Based Analysis of the Spatial Provision of Urban Parks in Shenzhen, China.

Science.gov (United States)

Gao, Wenxiu; Lyu, Qiang; Fan, Xiang; Yang, Xiaochun; Liu, Jiangtao; Zhang, Xirui

2017-12-06

Urban parks provide important environmental, social, and economic benefits to people and urban areas. The literature demonstrates that proximity to urban parks is one of the key factors influencing people's willingness to use them. Therefore, the provision of urban parks near residential areas and workplaces is one of the key factors influencing quality of life. This study designed a solution based on the spatial association between urban parks and buildings where people live or work to identify whether people in different buildings have nearby urban parks available for their daily lives. A building density map based on building floor area (BFA) was used to illustrate the spatial distribution of urban parks and five indices were designed to measure the scales, service coverage and potential service loads of urban parks and reveal areas lacking urban park services in an acceptable walking distance. With such solution, we investigated the provision of urban parks in ten districts of Shenzhen in China, which has grown from several small villages to a megacity in only 30 years. The results indicate that the spatial provision of urban parks in Shenzhen is not sufficient since people in about 65% of the buildings cannot access urban parks by walking 10-min. The distribution and service coverage of the existing urban parks is not balanced at the district level. In some districts, the existing urban parks have good numbers of potential users and even have large service loads, while in some districts, the building densities surrounding the existing parks are quite low and at the same time there is no urban parks nearby some high-density areas.

Estimating rural populations without access to electricity in developing countries through night-time light satellite imagery

International Nuclear Information System (INIS)

Doll, Christopher N.H.; Pachauri, Shonali

2010-01-01

A lack of access to energy and, in particular, electricity is a less obvious manifestation of poverty but arguably one of the most important. This paper investigates the extent to which electricity access can be investigated using night-time light satellite data and spatially explicit population datasets to compare electricity access between 1990 and 2000. We present here the first satellite derived estimates of rural population without access to electricity in developing countries to draw insights on issues surrounding the delivery of electricity to populations in rural areas. The paper provides additional evidence of the slow progress in expansion of energy access to households in Sub-Saharan Africa and shows how this might be ascribed in part due to the low population densities in rural areas. The fact that this is a continent with some of the lowest per-capita income levels aggravates the intrinsic difficulties associated with making the investments needed to supply electricity in areas with low population density and high dispersion. Clearly, these spatial dimensions of the distributions of the remaining unelectrified populations in the world have an impact on what options are considered the most appropriate in expanding access to these households and the relative attractiveness of decentralized options.

The role of a bus network in access to primary health care in Metropolitan Auckland, New Zealand.

Science.gov (United States)

Rocha, C M; McGuire, S; Whyman, R; Kruger, E; Tennant, M

2015-09-01

Background: This study examined the spatial accessibility of the population of metropolitan Auckland, New Zealand to the bus network, to connect them to primary health providers, in this case doctors (GP) and dentists. Analysis of accessibility by ethnic identity and socio-economic status were also carried out, because of existing health inequalities along these dimensions. The underlying hypothesis was that most people would live within easy reach of primary health providers, or easy bus transport to such providers. An integrated geographic model of bus transport routes and stops, with population and primary health providers (medical. and dental practices) was developed and analysed. Although the network of buses in metropolitan Auckland is substantial and robust it was evident that many people live more than 150 metres from a stop. Improving the access to bus stops, particularly in areas of high primary health care need (doctors and dentists), would certainly be an opportunity to enhance spatial access in a growing metropolitan area.

Elucidating the significance of spatial memory on movement decisions by African savannah elephants using state-space models.

Science.gov (United States)

Polansky, Leo; Kilian, Werner; Wittemyer, George

2015-04-22

Spatial memory facilitates resource acquisition where resources are patchy, but how it influences movement behaviour of wide-ranging species remains to be resolved. We examined African elephant spatial memory reflected in movement decisions regarding access to perennial waterholes. State-space models of movement data revealed a rapid, highly directional movement behaviour almost exclusively associated with visiting perennial water. Behavioural change point (BCP) analyses demonstrated that these goal-oriented movements were initiated on average 4.59 km, and up to 49.97 km, from the visited waterhole, with the closest waterhole accessed 90% of the time. Distances of decision points increased when switching to different waterholes, during the dry season, or for female groups relative to males, while selection of the closest waterhole decreased when switching. Overall, our analyses indicated detailed spatial knowledge over large scales, enabling elephants to minimize travel distance through highly directional movement when accessing water. We discuss the likely cognitive and socioecological mechanisms driving these spatially precise movements that are most consistent with our findings. By applying modern analytic techniques to high-resolution movement data, this study illustrates emerging approaches for studying how cognition structures animal movement behaviour in different ecological and social contexts. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Stable panoramic views facilitate snap-shot like memories for spatial reorientation in homing pigeons.

Directory of Open Access Journals (Sweden)

Tommaso Pecchia

Full Text Available Following spatial disorientation, animals can reorient themselves by relying on geometric cues (metric and sense specified both by the macroscopic surface layout of an enclosed space and prominent visual landmarks in arrays. Whether spatial reorientation in arrays of landmarks is based on explicit representation of the geometric cues is a matter of debate. Here we trained homing pigeons (Columba livia to locate a food-reward in a rectangular array of four identical or differently coloured pipes provided with four openings, only one of which allowed the birds to have access to the reward. Pigeons were trained either with a stable or a variable position of the opening on pipes, so that they could view the array either from the same or a variable perspective. Explicit mapping of configural geometry would predict successful reorientation irrespective of access condition. In contrast, we found that a stable view of the array facilitated spatial learning in homing pigeons, likely through the formation of snapshot-like memories.

Remote sensing of potential lunar resources. 2: High spatial resolution mapping of spectral reflectance ratios and implications for nearside mare TiO2 content`

Science.gov (United States)

Melendrez, David E.; Johnson, Jeffrey R.; Larson, Stephen M.; Singer, Robert B.

1994-01-01

High spatial resolution maps illustrating variations in spectral reflectance 400/560 nm ratio values have been generated for the following mare regions: (1) the border between southern Mare Serenitatis and northern Mare Tranquillitatis (including the MS-2 standard area and Apollo 17 landing site), (2) central Mare Tranquillitatis, (3) Oceanus Procellarum near Seleucus, and (4) southern Oceanus Procellarum and Flamsteed. We have also obtained 320-1000 nm reflectance spectra of several sites relative to MS-2 to facilitate scaling of the images and provide additional information on surface composition. Inferred TiO2 abundances for these mare regions have been determined using an empirical calibration which relates the weight percent TiO2 in mature mare regolith to the observed 400/560 nm ratio. Mare areas with high TiO2 abundances are probably rich in ilmenite (FeTiO3) a potential lunar resource. The highest potential TiO2 concentrations we have identified in the nearside maria occur in central Mare Tranquillitatis. Inferred TiO2 contents for these areas are greater than 9 wt% and are spatially consistent with the highest-TiO2 regions mapped previously at lower spatial resolution. We note that the morphology of surface units with high 400/560 nm ratio values increases in complexity at higher spatial resolutions. Comparisons have been made with previously published geologic maps, Lunar Orbiter IV, and ground-based images, and some possible morphologic correlatins have been found between our mapped 400/560 nm ratio values and volcanic landforms such as lava flows, mare domes, and collapse pits.

Housing accessibility problems for people with Parkinson's disease.

Science.gov (United States)

Slaug, B; Iwarsson, S; Ayala, J A; Nilsson, M H

2017-11-01

Promoting accessible housing for all citizens is high on the political agenda. Knowledge is, however, limited regarding housing accessibility problems for people with Parkinson's disease (PD). The objectives were to investigate housing accessibility problems among people with PD at different stages of disease severity and to analyze the potential impact of improved functional ability on accessibility problems. The study included 253 participants with PD (61% men; mean age 70 years). Disease severity was assessed by the Hoehn and Yahr (HY) I-V stages: HY I, n=50; II, n=73, III, n=66; IV-V, n=64. Using the Housing Enabler (HE) instrument, accessibility problems were investigated by combining assessments of the person's functional capacity with assessments of physical barriers in the housing environment into a person-environment fit measure (HE-score). To analyze potential impact of improved functional ability on housing accessibility problems, data simulation was applied. HE-scores differed significantly (Phousing accessibility problems for people with PD. The study also details environmental barriers that need specific attention when providing housing adaptation services. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Data Basin: Expanding Access to Conservation Data, Tools, and People

Science.gov (United States)

Comendant, T.; Strittholt, J.; Frost, P.; Ward, B. C.; Bachelet, D. M.; Osborne-Gowey, J.

2009-12-01

Mapping and spatial analysis are a fundamental part of problem solving in conservation science, yet spatial data are widely scattered, difficult to locate, and often unavailable. Valuable time and resources are wasted locating and gaining access to important biological, cultural, and economic datasets, scientific analysis, and experts. As conservation problems become more serious and the demand to solve them grows more urgent, a new way to connect science and practice is needed. To meet this need, an open-access, web tool called Data Basin (www.databasin.org) has been created by the Conservation Biology Institute in partnership with ESRI and the Wilburforce Foundation. Users of Data Basin can gain quick access to datasets, experts, groups, and tools to help solve real-world problems. Individuals and organizations can perform essential tasks such as exploring and downloading from a vast library of conservation datasets, uploading existing datasets, connecting to other external data sources, create groups, and produce customized maps that can be easily shared. Data Basin encourages sharing and publishing, but also provides privacy and security for sensitive information when needed. Users can publish projects within Data Basin to tell more complete and rich stories of discovery and solutions. Projects are an ideal way to publish collections of datasets, maps and other information on the internet to reach wider audiences. Data Basin also houses individual centers that provide direct access to data, maps, and experts focused on specific geographic areas or conservation topics. Current centers being developed include the Boreal Information Centre, the Data Basin Climate Center, and proposed Aquatic and Forest Conservation Centers.

Considering Peer Support for Self-Access Learning

Directory of Open Access Journals (Sweden)

Craig Manning

2014-01-01

Full Text Available This paper briefly examines if and how peer support can be implemented as an appropriate means to improve self-access learning. The potential for further alignment with the higher aims common among self-access learning centers will be examined. Opportunities for increasing interdependence, purpose, and level of challenge to foster student engagement will also be explored. Finally, future directions in self-access learning will be discussed.

Hierarchical spatial organization of geographical networks

International Nuclear Information System (INIS)

Travencolo, Bruno A N; Costa, Luciano da F

2008-01-01

In this work, we propose a hierarchical extension of the polygonality index as the means to characterize geographical planar networks. By considering successive neighborhoods around each node, it is possible to obtain more complete information about the spatial order of the network at progressive spatial scales. The potential of the methodology is illustrated with respect to synthetic and real geographical networks

Spatial analysis of "crazy quilts", a class of potentially random aesthetic artefacts.

Directory of Open Access Journals (Sweden)

Gesche Westphal-Fitch

Full Text Available Human artefacts in general are highly structured and often display ordering principles such as translational, reflectional or rotational symmetry. In contrast, human artefacts that are intended to appear random and non symmetrical are very rare. Furthermore, many studies show that humans find it extremely difficult to recognize or reproduce truly random patterns or sequences. Here, we attempt to model two-dimensional decorative spatial patterns produced by humans that show no obvious order. "Crazy quilts" represent a historically important style of quilt making that became popular in the 1870s, and lasted about 50 years. Crazy quilts are unusual because unlike most human artefacts, they are specifically intended to appear haphazard and unstructured. We evaluate the degree to which this intention was achieved by using statistical techniques of spatial point pattern analysis to compare crazy quilts with regular quilts from the same region and era and to evaluate the fit of various random distributions to these two quilt classes. We found that the two quilt categories exhibit fundamentally different spatial characteristics: The patch areas of crazy quilts derive from a continuous random distribution, while area distributions of regular quilts consist of Gaussian mixtures. These Gaussian mixtures derive from regular pattern motifs that are repeated and we suggest that such a mixture is a distinctive signature of human-made visual patterns. In contrast, the distribution found in crazy quilts is shared with many other naturally occurring spatial patterns. Centroids of patches in the two quilt classes are spaced differently and in general, crazy quilts but not regular quilts are well-fitted by a random Strauss process. These results indicate that, within the constraints of the quilt format, Victorian quilters indeed achieved their goal of generating random structures.

Spatial analysis of "crazy quilts", a class of potentially random aesthetic artefacts.

Science.gov (United States)

Westphal-Fitch, Gesche; Fitch, W Tecumseh

2013-01-01

Human artefacts in general are highly structured and often display ordering principles such as translational, reflectional or rotational symmetry. In contrast, human artefacts that are intended to appear random and non symmetrical are very rare. Furthermore, many studies show that humans find it extremely difficult to recognize or reproduce truly random patterns or sequences. Here, we attempt to model two-dimensional decorative spatial patterns produced by humans that show no obvious order. "Crazy quilts" represent a historically important style of quilt making that became popular in the 1870s, and lasted about 50 years. Crazy quilts are unusual because unlike most human artefacts, they are specifically intended to appear haphazard and unstructured. We evaluate the degree to which this intention was achieved by using statistical techniques of spatial point pattern analysis to compare crazy quilts with regular quilts from the same region and era and to evaluate the fit of various random distributions to these two quilt classes. We found that the two quilt categories exhibit fundamentally different spatial characteristics: The patch areas of crazy quilts derive from a continuous random distribution, while area distributions of regular quilts consist of Gaussian mixtures. These Gaussian mixtures derive from regular pattern motifs that are repeated and we suggest that such a mixture is a distinctive signature of human-made visual patterns. In contrast, the distribution found in crazy quilts is shared with many other naturally occurring spatial patterns. Centroids of patches in the two quilt classes are spaced differently and in general, crazy quilts but not regular quilts are well-fitted by a random Strauss process. These results indicate that, within the constraints of the quilt format, Victorian quilters indeed achieved their goal of generating random structures.

Qualitative Description of Spatial Quality in Inclusive Architecture

DEFF Research Database (Denmark)

Ryhl, Camilla; Kajita, Masashi; Sørensen, Rene

2016-01-01

Universal design (UD) has gained global significance and is in the process of institutionalisation in the Nordic Region. This is despite an urgent necessity for developing the theoretical basis and practical applicability of UD. Reflecting this need for furthering the comprehensive understanding ...... of assessment criteria is essential in order to support students and designers to make responsible decisions in shaping built environments that are accessible and inclusive but also enjoyable....... of spatial implication of UD, this paper aims to contribute for articulating a means to assess the quality of UD in architecture. Drawing upon numerous cases from research conducted at the Danish Building Research Institute, the paper focuses on sensory aspects of spatial quality, and discusses as well...

Supporting spatial data harmonization process with the use of ontologies and Semantic Web technologies

Science.gov (United States)

Strzelecki, M.; Iwaniak, A.; Łukowicz, J.; Kaczmarek, I.

2013-10-01

Nowadays, spatial information is not only used by professionals, but also by common citizens, who uses it for their daily activities. Open Data initiative states that data should be freely and unreservedly available for all users. It also applies to spatial data. As spatial data becomes widely available it is essential to publish it in form which guarantees the possibility of integrating it with other, heterogeneous data sources. Interoperability is the possibility to combine spatial data sets from different sources in a consistent way as well as providing access to it. Providing syntactic interoperability based on well-known data formats is relatively simple, unlike providing semantic interoperability, due to the multiple possible data interpretation. One of the issues connected with the problem of achieving interoperability is data harmonization. It is a process of providing access to spatial data in a representation that allows combining it with other harmonized data in a coherent way by using a common set of data product specification. Spatial data harmonization is performed by creating definition of reclassification and transformation rules (mapping schema) for source application schema. Creation of those rules is a very demanding task which requires wide domain knowledge and a detailed look into application schemas. The paper focuses on proposing methods for supporting data harmonization process, by automated or supervised creation of mapping schemas with the use of ontologies, ontology matching methods and Semantic Web technologies.

Optical Access Networks

Science.gov (United States)

Zheng, Jun; Ansari, Nirwan

2005-06-01

Call for Papers: Optical Access Networks With the wide deployment of fiber-optic technology over the past two decades, we have witnessed a tremendous growth of bandwidth capacity in the backbone networks of today's telecommunications infrastructure. However, access networks, which cover the "last-mile" areas and serve numerous residential and small business users, have not been scaled up commensurately. The local subscriber lines for telephone and cable television are still using twisted pairs and coaxial cables. Most residential connections to the Internet are still through dial-up modems operating at a low speed on twisted pairs. As the demand for access bandwidth increases with emerging high-bandwidth applications, such as distance learning, high-definition television (HDTV), and video on demand (VoD), the last-mile access networks have become a bandwidth bottleneck in today's telecommunications infrastructure. To ease this bottleneck, it is imperative to provide sufficient bandwidth capacity in the access networks to open the bottleneck and thus present more opportunities for the provisioning of multiservices. Optical access solutions promise huge bandwidth to service providers and low-cost high-bandwidth services to end users and are therefore widely considered the technology of choice for next-generation access networks. To realize the vision of optical access networks, however, many key issues still need to be addressed, such as network architectures, signaling protocols, and implementation standards. The major challenges lie in the fact that an optical solution must be not only robust, scalable, and flexible, but also implemented at a low cost comparable to that of existing access solutions in order to increase the economic viability of many potential high-bandwidth applications. In recent years, optical access networks have been receiving tremendous attention from both academia and industry. A large number of research activities have been carried out or

An analysis of the accessibility of video lottery terminals: the case of Montréal

Directory of Open Access Journals (Sweden)

Herjean Patrick

2008-01-01

Full Text Available Abstract Background Researchers and public health officials in Canada, the United States and Australia have for some time noted broader geographic accessibility to gambling establishments, above all in socioeconomically underprivileged communities. This increase in availability could lead to more and more gambling problems. This article focuses, in an ecological perspective, in particular on a spatial analysis of the geographic accessibility of sites possessing a VLT permit in the Montréal area, i.e. Montréal Island, the South Shore and Laval, from the standpoint of the development of an indicator of the vulnerability (socioeconomic components and demographic components to gambling of populations at the level of certain neighbourhood units (dissemination areas. With the recent development of geographic information systems (GIS, it is now possible to ascertain accessibility to services much more accurately, for example by taking into account the configuration of the road network. Results The findings of our analysis reveal widespread geographic accessibility to sites possessing a VLT permit in the downtown area and in pericentral districts. In some neighbourhood units, a site possessing a VLT permit may be within a three-minute walk. In the region studied overall, average walking time to a VLT site is nine minutes. Access to this type of service on foot is usually limited in the outskirts. However, a number of groups of sites possessing VLT permits are found along certain axial highways. According to local spatial self-correlation analyses, the findings suggest a significant link between walking accessibility to sites possessing VLT permits and the vulnerability of the communities. In a number of neighbourhood units with ready access to VLT's the populations display high vulnerability. Conclusion These findings reveal that accessibility to sites possessing a VLT permit is often linked to the vulnerability (socioeconomic and demographic

ABSORPTION, SCATTERING, ATTENUATION COEFFICIENTS and Other Data from 19920101 to 19931231 (NCEI Accession 9600076)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The accession contains satellite spatially-averaged Sea Surface Temperature data collected as part of Tropical Ocean Global Atmosphere (TOGA). The data was collected...

Access control and privilege management in electronic health record: a systematic literature review.

Science.gov (United States)

Jayabalan, Manoj; O'Daniel, Thomas

2016-12-01

This study presents a systematic literature review of access control for electronic health record systems to protect patient's privacy. Articles from 2006 to 2016 were extracted from the ACM Digital Library, IEEE Xplore Digital Library, Science Direct, MEDLINE, and MetaPress using broad eligibility criteria, and chosen for inclusion based on analysis of ISO22600. Cryptographic standards and methods were left outside the scope of this review. Three broad classes of models are being actively investigated and developed: access control for electronic health records, access control for interoperability, and access control for risk analysis. Traditional role-based access control models are extended with spatial, temporal, probabilistic, dynamic, and semantic aspects to capture contextual information and provide granular access control. Maintenance of audit trails and facilities for overriding normal roles to allow full access in emergency cases are common features. Access privilege frameworks utilizing ontology-based knowledge representation for defining the rules have attracted considerable interest, due to the higher level of abstraction that makes it possible to model domain knowledge and validate access requests efficiently.

The effect of perceptual load on tactile spatial attention: Evidence from event-related potentials.

Science.gov (United States)

Gherri, Elena; Berreby, Fiona

2017-10-15

To investigate whether tactile spatial attention is modulated by perceptual load, behavioural and electrophysiological measures were recorded during two spatial cuing tasks in which the difficulty of the target/non-target discrimination was varied (High and Low load tasks). Moreover, to study whether attentional modulations by load are sensitive to the availability of visual information, the High and Low load tasks were carried out under both illuminated and darkness conditions. ERPs to cued and uncued non-targets were compared as a function of task (High vs. Low load) and illumination condition (Light vs. Darkness). Results revealed that the locus of tactile spatial attention was determined by a complex interaction between perceptual load and illumination conditions during sensory-specific stages of processing. In the Darkness, earlier effects of attention were present in the High load than in the Low load task, while no difference between tasks emerged in the Light. By contrast, increased load was associated with stronger attention effects during later post-perceptual processing stages regardless of illumination conditions. These findings demonstrate that ERP correlates of tactile spatial attention are strongly affected by the perceptual load of the target/non-target discrimination. However, differences between illumination conditions show that the impact of load on tactile attention depends on the presence of visual information. Perceptual load is one of the many factors that contribute to determine the effects of spatial selectivity in touch. Copyright © 2017 Elsevier B.V. All rights reserved.

Questioning territorial cohesion: (Un)equal access to services of general interest

Czech Academy of Sciences Publication Activity Database

Malý, Jiří

-, August 2016 (2016), s. 1-21 ISSN 1056-8190 Institutional support: RVO:68145535 Keywords : territorial cohesion * services of general interest * accessibility * spatial justice * Czech Republic Subject RIV: DE - Earth Magnetism, Geodesy, Geography Impact factor: 1.272, year: 2016 http://onlinelibrary.wiley.com/doi/10.1111/pirs.12250/full

Diffusion accessibility as a method for visualizing macromolecular surface geometry.

Science.gov (United States)

Tsai, Yingssu; Holton, Thomas; Yeates, Todd O

2015-10-01

Important three-dimensional spatial features such as depth and surface concavity can be difficult to convey clearly in the context of two-dimensional images. In the area of macromolecular visualization, the computer graphics technique of ray-tracing can be helpful, but further techniques for emphasizing surface concavity can give clearer perceptions of depth. The notion of diffusion accessibility is well-suited for emphasizing such features of macromolecular surfaces, but a method for calculating diffusion accessibility has not been made widely available. Here we make available a web-based platform that performs the necessary calculation by solving the Laplace equation for steady state diffusion, and produces scripts for visualization that emphasize surface depth by coloring according to diffusion accessibility. The URL is http://services.mbi.ucla.edu/DiffAcc/. © 2015 The Protein Society.

Spatially extended versus frontal cerebral near-infrared spectroscopy during cardiac surgery: a case series identifying potential advantages

Science.gov (United States)

Rummel, Christian; Basciani, Reto; Nirkko, Arto; Schroth, Gerhard; Stucki, Monika; Reineke, David; Eberle, Balthasar; Kaiser, Heiko A.

2018-01-01

Stroke due to hypoperfusion or emboli is a devastating adverse event of cardiac surgery, but early detection and treatment could protect patients from an unfavorable postoperative course. Hypoperfusion and emboli can be detected with transcranial Doppler of the middle cerebral artery (MCA). The measured blood flow velocity correlates with cerebral oxygenation determined clinically by near-infrared spectroscopy (NIRS) of the frontal cortex. We tested the potential advantage of a spatially extended NIRS in detecting critical events in three cardiac surgery patients with a whole-head fiber holder of the FOIRE-3000 continuous-wave NIRS system. Principle components analysis was performed to differentiate between global and localized hypoperfusion or ischemic territories of the middle and anterior cerebral arteries. In one patient, we detected a critical hypoperfusion of the right MCA, which was not apparent in the frontal channels but was accompanied by intra- and postoperative neurological correlates of ischemia. We conclude that spatially extended NIRS of temporal and parietal vascular territories could improve the detection of critically low cerebral perfusion. Even in severe hemispheric stroke, NIRS of the frontal lobe may remain normal because the anterior cerebral artery can be supplied by the contralateral side directly or via the anterior communicating artery.

Freight on a Low-Carbon Diet: Accessibility, Freightsheds, and Commodities.

Science.gov (United States)

Taptich, Michael N; Horvath, Arpad

2015-10-06

The freight infrastructure network (e.g., roads, railways, waterways, etc.) is the backbone of nearly all trade partnerships in the United States and abroad. The manner in which the individual portions of its constituent parts are interrelated or arranged plays an important role for determining the environmental footprint of goods moved within the network. Herein, we compare the spatial distribution of potential consumer-producer exchanges (i.e., accessibility) under varying greenhouse gas (GHG) budgets or preferences for minimal transportation-related GHG emissions. We conduct case studies using two freight modes (truck and intermodal rail) for two representative commodities: meat/seafood and paper articles. Results across all counties in the United States indicate that the geographic area in which trade is possible, given a GHG budget, varies by transportation mode, location, and commodity. Our results suggest that intermodal terminal availability is an important determinant of low-GHG accessibility. Since only a fraction of road-to-rail terminals accommodate meat/seafood (4.9%) and paper (0.7%), the United States could increase its expected GHG savings associated with truck-to-rail mode-switching policies by 70% (+20 kg CO2,e/ton for meat/seafood) and 310% (+30 kg CO2,e/ton for paper) by upgrading current terminals to allow the exchange of all types of goods.

Relations between nature-based solutions of green-blue area accessibility and socio-economic-ethnic patterns in the urban Stockholm region

Science.gov (United States)

Goldenberg, Romain; Kalantari, Zahra; Destouni, Georgia

2017-04-01

More than half of the world's population lives in cities, a proportion expected to increase to two thirds by 2050 (United Nations (UN), 2015). In this study, we investigate the spatial relationships that may exist between income and/or nationality homogeneity/heterogeneity levels of urban populations and their accessibility to local green-blue areas as possible nature-based solutions for sustainable urban design. For this investigation, we consider as a concrete case study the urban region of Stockholm, Sweden, for which we compile and use available land-cover and vegetation density data (the latter in terms of Normalised Difference Vegetation Index, NDVI) in order to identify and assess the spatial distributions of various green-blue area types and aspects. We further combine this data with spatial distribution data for population density, income and nationality, as well as with road-network data for assessing population travel times to nearby green-blue areas within the region. The present study results converge with those of other recent studies in showing large socio-economic-ethnic segregation in the Stockholm region. Moreover, the present data combination and analysis also show large spatial differences in and important socio-economic-ethnic correlations with accessibility to local green areas and nearby water bodies. Specifically, population income and share of Swedish nationals are well correlated in this region, with increases in both of these variables implying greater possibility to choose where to live within the region. The living choices of richer and more homogeneous (primarily Swedish) population parts are then found to be areas with greater local vegetation density (local green areas as identified by high-resolution NDVI data) and greater area extent of nearby water bodies (blue areas). For comparison, no such correlation is found between increased income or Swedish nationality homogeneity and accessibility to nearby forest areas (overall green

The Spatial Politics of Spatial Representation

DEFF Research Database (Denmark)

Olesen, Kristian; Richardson, Tim

2011-01-01

spatial planning in Denmark reveals how fuzzy spatial representations and relational spatial concepts are being used to depoliticise strategic spatial planning processes and to camouflage spatial politics. The paper concludes that, while relational geography might play an important role in building......This paper explores the interplay between the spatial politics of new governance landscapes and innovations in the use of spatial representations in planning. The central premise is that planning experiments with new relational approaches become enmeshed in spatial politics. The case of strategic...

Recreational potential as an indicator of accessibility control in protected mountain forest areas

Institute of Scientific and Technical Information of China (English)

Tomasz DUDEK

2017-01-01

The article presents research findings related to recreational use of forests located in protected mountainous areas with forestage of over 80％.The study was designed to identify recreational potential of the Carpathian national parks (Bieszczady National Park,Babia Góra National Park,Gorce National Park and Magura National Park;southern Poland) and to compare these findings with the actual number of visitors.The information received on the recreational potential of parks is important from the point of view of protection of natural resources and the financial situation of the parks.The calculated ratio may be an effective tool of management for park administration,that allows to reconcile statutory social and protective functions of national parks.The study determined the recreational potential of the forests with the use of recreational valorisation method designed for areas with varied terrain,and the evaluated factors included the stands of trees with their habitat and land relief.The permissible number of national park visitors,expressed as manhour/ha/year ranges from 19.31 in Bieszczady National Park (BG:19° 35′ E,49° 35′ N) to 32.06 in in Bieszczady National Park (B:22° 40′ E,49° 10′ N).In 3 out of 4 investigated parks,Magnra National Park (M:21°25′ E,49° 30′ N),Gorce National Park (G:20° 10′ E,49° 35′ N),B) recreation carrying capacity was not exceeded,whether or not the strictly protected area is taken into account.Only in BG was the recreation carrying capacity exceeded by nearly 24％,or by 85％ if the strictly protected area is excluded from tourism-related exploitation.The presented procedure for monitoring access to mountain forests in national parks,from the viewpoint of natural resources conservation,can be applied in other mountainous areas covered with forests and exposed to tourist and recreational traffic,and in forests facing particular risk of recreational damage,e.g.in urban and suburban forests growing in areas

Multiple-Antenna Interference Cancellation for WLAN with MAC Interference Avoidance in Open Access Networks

Directory of Open Access Journals (Sweden)

Alexandr M. Kuzminskiy

2007-10-01

Full Text Available The potential of multiantenna interference cancellation receiver algorithms for increasing the uplink throughput in WLAN systems such as 802.11 is investigated. The medium access control (MAC in such systems is based on carrier sensing multiple-access with collision avoidance (CSMA/CA, which itself is a powerful tool for the mitigation of intrasystem interference. However, due to the spatial dependence of received signal strengths, it is possible for the collision avoidance mechanism to fail, resulting in packet collisions at the receiver and a reduction in system throughput. The CSMA/CA MAC protocol can be complemented in such scenarios by interference cancellation (IC algorithms at the physical (PHY layer. The corresponding gains in throughput are a result of the complex interplay between the PHY and MAC layers. It is shown that semiblind interference cancellation techniques are essential for mitigating the impact of interference bursts, in particular since these are typically asynchronous with respect to the desired signal burst. Semiblind IC algorithms based on second- and higher-order statistics are compared to the conventional no-IC and training-based IC techniques in an open access network (OAN scenario involving home and visiting users. It is found that the semiblind IC algorithms significantly outperform the other techniques due to the bursty and asynchronous nature of the interference caused by the MAC interference avoidance scheme.

Multiple-Antenna Interference Cancellation for WLAN with MAC Interference Avoidance in Open Access Networks

Directory of Open Access Journals (Sweden)

Kuzminskiy Alexandr M

2007-01-01

Full Text Available The potential of multiantenna interference cancellation receiver algorithms for increasing the uplink throughput in WLAN systems such as 802.11 is investigated. The medium access control (MAC in such systems is based on carrier sensing multiple-access with collision avoidance (CSMA/CA, which itself is a powerful tool for the mitigation of intrasystem interference. However, due to the spatial dependence of received signal strengths, it is possible for the collision avoidance mechanism to fail, resulting in packet collisions at the receiver and a reduction in system throughput. The CSMA/CA MAC protocol can be complemented in such scenarios by interference cancellation (IC algorithms at the physical (PHY layer. The corresponding gains in throughput are a result of the complex interplay between the PHY and MAC layers. It is shown that semiblind interference cancellation techniques are essential for mitigating the impact of interference bursts, in particular since these are typically asynchronous with respect to the desired signal burst. Semiblind IC algorithms based on second- and higher-order statistics are compared to the conventional no-IC and training-based IC techniques in an open access network (OAN scenario involving home and visiting users. It is found that the semiblind IC algorithms significantly outperform the other techniques due to the bursty and asynchronous nature of the interference caused by the MAC interference avoidance scheme.

The spatial resolution in dosimetry with normoxic polymer-gels investigated with the dose modulation transfer approach

International Nuclear Information System (INIS)

Bayreder, Christian; Schoen, Robert; Wieland, M.; Georg, Dietmar; Moser, Ewald; Berg, Andreas

2008-01-01

The verification of dose distributions with high dose gradients as appearing in brachytherapy or stereotactic radiotherapy for example, calls for dosimetric methods with sufficiently high spatial resolution. Polymer gels in combination with a MR or optical scanner as a readout device have the potential of performing the verification of a three-dimensional dose distribution within a single measurement. The purpose of this work is to investigate the spatial resolution achievable in MR-based polymer gel dosimetry. The authors show that dosimetry on a very small spatial scale (voxel size: 94x94x1000 μm 3 ) can be performed with normoxic polymer gels using parameter selective T2 imaging. In order to prove the spatial resolution obtained we are relying on the dose-modulation transfer function (DMTF) concept based on very fine dose modulations at half periods of 200 μm. Very fine periodic dose modulations of a 60 Co photon field were achieved by means of an absorption grid made of tungsten-carbide, specifically designed for quality control. The dose modulation in the polymer gel is compared with that of film dosimetry in one plane via the DMTF concept for general access to the spatial resolution of a dose imaging system. Additionally Monte Carlo simulations were performed and used for the calculation of the DMTF of both, the polymer gel and film dosimetry. The results obtained by film dosimetry agree well with those of Monte Carlo simulations, whereas polymer gel dosimetry overestimates the amplitude value of the fine dose modulations. The authors discuss possible reasons. The in-plane resolution achieved in this work competes with the spatial resolution of standard clinical film-scanner systems

Qualitative Description of Spatial Quality in Inclusive Architecture.

Science.gov (United States)

Ryhl, Camilla; Kajita, Masashi; Sørensen, René

2016-01-01

Universal design (UD) has gained global significance and is in the process of institutionalisation in the Nordic Region. This is despite an urgent necessity for developing the theoretical basis and practical applicability of UD. Reflecting this need for furthering the comprehensive understanding of spatial implication of UD, this paper aims to contribute for articulating a means to assess the quality of UD in architecture. Drawing upon numerous cases from research conducted at the Danish Building Research Institute, the paper focuses on sensory aspects of spatial quality, and discusses as well as reflects an applied method for producing the qualitative description of selected buildings that embody UD through creative solutions. The qualitative description of collected examples appears to be effective in delineating sensory aspects of spatial experience; however the systematic development of assessment criteria is essential in order to support students and designers to make responsible decisions in shaping built environments that are accessible and inclusive but also enjoyable.

Remote Sensing of River Delta Inundation: Exploiting the Potential of Coarse Spatial Resolution, Temporally-Dense MODIS Time Series

Directory of Open Access Journals (Sweden)

Claudia Kuenzer

2015-07-01

Full Text Available River deltas belong to the most densely settled places on earth. Although they only account for 5% of the global land surface, over 550 million people live in deltas. These preferred livelihood locations, which feature flat terrain, fertile alluvial soils, access to fluvial and marine resources, a rich wetland biodiversity and other advantages are, however, threatened by numerous internal and external processes. Socio-economic development, urbanization, climate change induced sea level rise, as well as flood pulse changes due to upstream water diversion all lead to changes in these highly dynamic systems. A thorough understanding of a river delta’s general setting and intra-annual as well as long-term dynamic is therefore crucial for an informed management of natural resources. Here, remote sensing can play a key role in analyzing and monitoring these vast areas at a global scale. The goal of this study is to demonstrate the potential of intra-annual time series analyses at dense temporal, but coarse spatial resolution for inundation characterization in five river deltas located in four different countries. Based on 250 m MODIS reflectance data we analyze inundation dynamics in four densely populated Asian river deltas—namely the Yellow River Delta (China, the Mekong Delta (Vietnam, the Irrawaddy Delta (Myanmar, and the Ganges-Brahmaputra (Bangladesh, India—as well as one very contrasting delta: the nearly uninhabited polar Mackenzie Delta Region in northwestern Canada for the complete time span of one year (2013. A complex processing chain of water surface derivation on a daily basis allows the generation of intra-annual time series, which indicate inundation duration in each of the deltas. Our analyses depict distinct inundation patterns within each of the deltas, which can be attributed to processes such as overland flooding, irrigation agriculture, aquaculture, or snowmelt and thermokarst processes. Clear differences between mid

Education Scholars' Perceptions and Practices toward Open Access Publishing

Science.gov (United States)

Ellingford, Lori Michelle

2012-01-01

Although open access publishing has been available since 1998, we know little regarding scholars' perceptions and practices toward publishing in open access outlets, especially in the social science community. Open access publishing has been slow to penetrate the field of education, yet the potential impact of open access could make this…

Diving into the consumer nutrition environment: A Bayesian spatial factor analysis of neighborhood restaurant environment.

Science.gov (United States)

Luan, Hui; Law, Jane; Lysy, Martin

2018-02-01

Neighborhood restaurant environment (NRE) plays a vital role in shaping residents' eating behaviors. While NRE 'healthfulness' is a multi-facet concept, most studies evaluate it based only on restaurant type, thus largely ignoring variations of in-restaurant features. In the few studies that do account for such features, healthfulness scores are simply averaged over accessible restaurants, thereby concealing any uncertainty that attributed to neighborhoods' size or spatial correlation. To address these limitations, this paper presents a Bayesian Spatial Factor Analysis for assessing NRE healthfulness in the city of Kitchener, Canada. Several in-restaurant characteristics are included. By treating NRE healthfulness as a spatially correlated latent variable, the adopted modeling approach can: (i) identify specific indicators most relevant to NRE healthfulness, (ii) provide healthfulness estimates for neighborhoods without accessible restaurants, and (iii) readily quantify uncertainties in the healthfulness index. Implications of the analysis for intervention program development and community food planning are discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Correlates of Access to Business Research Databases

Science.gov (United States)

Gottfried, John C.

2010-01-01

This study examines potential correlates of business research database access through academic libraries serving top business programs in the United States. Results indicate that greater access to research databases is related to enrollment in graduate business programs, but not to overall enrollment or status as a public or private institution.…

The spatial glaciological data infrastructure

Directory of Open Access Journals (Sweden)

T. Y. Khromova

2014-01-01

Full Text Available Substantial and rapid environmental changes require developing methods which could be able to manage huge information flows, to optimize processes of the data acquisition, storage, analysis, and exchange. Such facilities can be provided by the newly developed GIS technologies. Digital data bases are used as the key component of the GIS methods. We present the system of glaciological data management, developed in the Institute of Geography of Russian Academy of Sciences (IGRAS. Digital Atlas «Snow and Ice on the Earth», glacier inventories and digital library are the basic structures making possible objective presentation of the glaciological knowledge and data. The system provides the data integration, access to the data base, and makes possible using the GIS techniques for analysis. Data integration technologies are designed to form the united information space of subject areas of the spatial data. The objects of integration in our study are the information resources of glaciology, accumulated in a distributed system of data on the IGRAS web servers and geoportals in forms of data and metadata bases, structured (in a particular format data files, object data files (plain text, documents, images, etc., and electronic atlases. The best option for formation of a large-scale distributed environment, integration of many information resources of glaciology is to provide the so-called interoperability of data. This refers to compliance with certain rules or usage of additional software tools that allows interaction between various spatial data. These are standards to which the integrated information resources of glaciology should satisfy. The result of integration of the glaciological data technology application is the series of software and technology solutions. The main result of this work is creation of geoportals «Electronic Earth» (www.webgeo.ru, «The Nature and Resources of the Russian North» (www.north.webgeo.ru, «IPY-IGRAS» (www

Energy access. Current situation, challenges and outlook

International Nuclear Information System (INIS)

2014-07-01

Globally over 1.3 billion people do not have access to electricity and 2.6 billion people rely on the traditional use of biomass for cooking. Energy access is one of the major challenges of the 21. century as it is a lever for both economic and human development, at individual and national level. Moreover, energy access represents a high-potential market and offers a lot of opportunities for private companies and industrials. In this publication, ENEA lays out the current situation of energy access (actors, actual and future needs, existing technological solutions, markets). The publication addresses the main issues energy access has to face: energy price, equipment financing, distribution, scale-up, and environmental performances

Spatial access method for urban geospatial database management: An efficient approach of 3D vector data clustering technique

DEFF Research Database (Denmark)

Azri, Suhaibah; Ujang, Uznir; Rahman, Alias Abdul

2014-01-01

In the last few years, 3D urban data and its information are rapidly increased due to the growth of urban area and urbanization phenomenon. These datasets are then maintain and manage in 3D spatial database system. However, performance deterioration is likely to happen due to the massiveness of 3D...... datasets. As a solution, 3D spatial index structure is used as a booster to increase the performance of data retrieval. In commercial database, commonly and widely used index structure for 3D spatial database is 3D R-Tree. This is due to its simplicity and promising method in handling spatial data. However......D geospatial data clustering to be used in the construction of 3D R-Tree and respectively could reduce the overlapping among nodes. The proposed method is tested on 3D urban dataset for the application of urban infill development. By using several cases of data updating operations such as building...

The Spatial Patterns of Dairy Farming In Molise

Directory of Open Access Journals (Sweden)

Ievoli Corrado

2017-12-01

Full Text Available The greater market orientation of European dairy production, caused by the end of quota regime, is likely to have consequences on less favoured areas, where breeding of dairy cattle plays both a crucial socio-economic and environmental role. Within this new framework, endogenous factors determining spatial reorganisation of the sector are becoming of increasing relevance. Based on these considerations, this study analyses the impact of the three broader classes of location determinants suggested by economic theory - factor endowment, market potential, and spatial agglomeration externalities - on the spatial pattern of milk production in Molise, a rural region in the south of Italy. Milk production is measured in term of dairy cows per hectare. The truncated distribution of this variable and its high degree of spatial autocorrelation prompted us to apply a Spatial Autoregressive Tobit model. Estimation results reveal that all three categories have a positive effect on the location of milk production, even if the influence of factor endowment (intended as forage area, and market potential (measured in term of proximity of dairy companies is quite limited. On the contrary, the impact of spatial externalities (related variety on the regional localisation of milk production is strongly significant. These results cast some doubts on the current measures of intervention and might suggest a new policy framework both at firm and spatial level

How to Recognize and Avoid Potential, Possible, or Probable Predatory Open-Access Publishers, Standalone, and Hijacked Journals.

Science.gov (United States)

Danevska, Lenche; Spiroski, Mirko; Donev, Doncho; Pop-Jordanova, Nada; Polenakovic, Momir

2016-11-01

The Internet has enabled an easy method to search through the vast majority of publications and has improved the impact of scholarly journals. However, it can also pose threats to the quality of published articles. New publishers and journals have emerged so-called open-access potential, possible, or probable predatory publishers and journals, and so-called hijacked journals. It was our aim to increase the awareness and warn scholars, especially young researchers, how to recognize these journals and how to avoid submission of their papers to these journals. Review and critical analysis of the relevant published literature, Internet sources and personal experience, thoughts, and observations of the authors. The web blog of Jeffrey Beall, University of Colorado, was greatly consulted. Jeffrey Beall is a Denver academic librarian who regularly maintains two lists: the first one, of potential, possible, or probable predatory publishers and the second one, of potential, possible, or probable predatory standalone journals. Aspects related to this topic presented by other authors have been discussed as well. Academics should bear in mind how to differentiate between trustworthy and reliable journals and predatory ones, considering: publication ethics, peer-review process, international academic standards, indexing and abstracting, preservation in digital repositories, metrics, sustainability, etc.

Social Reproduction and College Access: Current Evidence, Context, and Potential Alternatives

Science.gov (United States)

Serna, Gabriel R.; Woulfe, Rebecca

2017-01-01

Social reproduction theory identifies schooling as a primary means for the perpetuation of the dominant class's ideologies, values, and power. The ability to access college is so closely tied to these constructs that it contributes to this dominance and marginalization. Social stratification is not only mirrored in higher education, but the…

Detecting spatial regimes in ecosystems | Science Inventory ...

Science.gov (United States)

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

Emissions from residential combustion considering end-uses and spatial constraints: Part I, methods and spatial distribution

Science.gov (United States)

Winijkul, Ekbordin; Fierce, Laura; Bond, Tami C.

2016-01-01

This study describes a framework to attribute national-level atmospheric emissions in the year 2010 from the residential sector, one of the largest energy-related sources of aerosol emissions. We place special emphasis on end-uses, dividing usage into cooking, heating, lighting, and others. This study covers regions where solid biomass fuel provides more than 50% of total residential energy: Latin America, Africa, and Asia (5.2 billion people in 2010). Using nightlight data and population density, we classify five land types: urban, electrified rural with forest access, electrified rural without forest access, non-electrified rural with forest access, and non-electrified rural without forest access. We then apportion national-level residential fuel consumption among all land-types and end-uses, and assign end-use technologies to each combination. The resulting calculation gives spatially-distributed emissions of particulate matter, black carbon, organic carbon, nitrogen oxides, methane, non-methane hydrocarbons, carbon monoxide, and carbon dioxide. Within this study region, about 13% of the energy is consumed in urban areas, and 45% in non-urban land near forests. About half the energy is consumed in land without access to electricity. Cooking accounts for 54% of the consumption, heating for 9%, and lighting only 2%, with unidentified uses making up the remainder. Because biofuel use is assumed to occur preferentially where wood is accessible and electricity is not, our method shifts emissions to land types without electrification, compared with previous methods. The framework developed here is an important first step in acknowledging the role of household needs and local constraints in choosing energy provision. Although data and relationships described here need further development, this structure offers a more physically-based understanding of residential energy choices and, ultimately, opportunities for emission reduction.

Access all areas? An area-level analysis of accessibility to general practice and community pharmacy services in England by urbanity and social deprivation.

Science.gov (United States)

Todd, Adam; Copeland, Alison; Husband, Andy; Kasim, Adetayo; Bambra, Clare

2015-05-08

(1) To determine the percentage of the population in England that has access to a general practitioner (GP) premises within a 20 min walk (the accessibility); (2) explore the relationship between the walking distance to a GP premises and urbanity and social deprivation and (3) compare accessibility of a GP premises to that of a community pharmacy--and how this may vary by urbanity and social deprivation. This area-level analysis spatial study used postcodes for all GP premises and community pharmacies in England. Each postcode was assigned to a population lookup table and Lower Super Output Area (LSOA). The LSOA was then matched to urbanity (urban, town and fringe, or village, hamlet and isolated dwellings) and deprivation decile (using the Index of Multiple Deprivation score 2010). Living within a 20 min walk of a GP premises. Overall, 84.8% of the population is estimated to live within a 20 min walk of a GP premises: 81.2% in the most affluent areas, 98.2% in the most deprived areas, 94.2% in urban and 19.4% in rural areas. This is consistently lower when compared with the population living within a 20 min walk of a community pharmacy. Our study shows that the vast majority of the population live within a 20 min walk of a GP premises, with higher proportions in the most deprived areas--a positive primary care law. However, more people live within a 20 min walk of a community pharmacy compared with a GP premises, and this potentially has implications for the commissioning of future services from these healthcare providers in England. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Accessing Information in Working Memory: Can the Focus of Attention Grasp Two Elements at the Same Time?

Science.gov (United States)

Oberauer, Klaus; Bialkova, Svetlana

2009-01-01

Processing information in working memory requires selective access to a subset of working-memory contents by a focus of attention. Complex cognition often requires joint access to 2 items in working memory. How does the focus select 2 items? Two experiments with an arithmetic task and 1 with a spatial task investigate time demands for successive…

Mapping the evolution of 'food deserts' in a Canadian city: Supermarket accessibility in London, Ontario, 1961–2005

Directory of Open Access Journals (Sweden)

Gilliland Jason

2008-04-01

Full Text Available Abstract Background A growing body of research suggests that the suburbanization of food retailers in North America and the United Kingdom in recent decades has contributed to the emergence of urban 'food deserts', or disadvantaged areas of cities with relatively poor access to healthy and affordable food. This paper explores the evolution of food deserts in a mid-sized Canadian city (London, Ontario by using a geographic information system (GIS to map the precise locations of supermarkets in 1961 and 2005; multiple techniques of network analysis were used to assess changing levels of supermarket access in relation to neighbourhood location, socioeconomic characteristics, and access to public transit. Results The findings indicate that residents of inner-city neighbourhoods of low socioeconomic status have the poorest access to supermarkets. Furthermore, spatial inequalities in access to supermarkets have increased over time, particularly in the inner-city neighbourhoods of Central and East London, where distinct urban food deserts now exist. Conclusion Contrary to recent findings in larger Canadian cities, we conclude that urban food deserts exist in London, Ontario. Policies aimed at improving public health must also recognize the spatial, as well as socioeconomic, inequities with respect to access to healthy and affordable food. Additional research is necessary to better understand how supermarket access influences dietary behaviours and related health outcomes.

Mapping the evolution of 'food deserts' in a Canadian city: Supermarket accessibility in London, Ontario, 1961–2005

Science.gov (United States)

Larsen, Kristian; Gilliland, Jason

2008-01-01

Background A growing body of research suggests that the suburbanization of food retailers in North America and the United Kingdom in recent decades has contributed to the emergence of urban 'food deserts', or disadvantaged areas of cities with relatively poor access to healthy and affordable food. This paper explores the evolution of food deserts in a mid-sized Canadian city (London, Ontario) by using a geographic information system (GIS) to map the precise locations of supermarkets in 1961 and 2005; multiple techniques of network analysis were used to assess changing levels of supermarket access in relation to neighbourhood location, socioeconomic characteristics, and access to public transit. Results The findings indicate that residents of inner-city neighbourhoods of low socioeconomic status have the poorest access to supermarkets. Furthermore, spatial inequalities in access to supermarkets have increased over time, particularly in the inner-city neighbourhoods of Central and East London, where distinct urban food deserts now exist. Conclusion Contrary to recent findings in larger Canadian cities, we conclude that urban food deserts exist in London, Ontario. Policies aimed at improving public health must also recognize the spatial, as well as socioeconomic, inequities with respect to access to healthy and affordable food. Additional research is necessary to better understand how supermarket access influences dietary behaviours and related health outcomes. PMID:18423005

Ibmdbpy-spatial : An Open-source implementation of in-database geospatial analytics in Python

Science.gov (United States)

Roy, Avipsa; Fouché, Edouard; Rodriguez Morales, Rafael; Moehler, Gregor

2017-04-01

As the amount of spatial data acquired from several geodetic sources has grown over the years and as data infrastructure has become more powerful, the need for adoption of in-database analytic technology within geosciences has grown rapidly. In-database analytics on spatial data stored in a traditional enterprise data warehouse enables much faster retrieval and analysis for making better predictions about risks and opportunities, identifying trends and spot anomalies. Although there are a number of open-source spatial analysis libraries like geopandas and shapely available today, most of them have been restricted to manipulation and analysis of geometric objects with a dependency on GEOS and similar libraries. We present an open-source software package, written in Python, to fill the gap between spatial analysis and in-database analytics. Ibmdbpy-spatial provides a geospatial extension to the ibmdbpy package, implemented in 2015. It provides an interface for spatial data manipulation and access to in-database algorithms in IBM dashDB, a data warehouse platform with a spatial extender that runs as a service on IBM's cloud platform called Bluemix. Working in-database reduces the network overload, as the complete data need not be replicated into the user's local system altogether and only a subset of the entire dataset can be fetched into memory in a single instance. Ibmdbpy-spatial accelerates Python analytics by seamlessly pushing operations written in Python into the underlying database for execution using the dashDB spatial extender, thereby benefiting from in-database performance-enhancing features, such as columnar storage and parallel processing. The package is currently supported on Python versions from 2.7 up to 3.4. The basic architecture of the package consists of three main components - 1) a connection to the dashDB represented by the instance IdaDataBase, which uses a middleware API namely - pypyodbc or jaydebeapi to establish the database connection via

Does Access Trump Ownership? Exploring Consumer Acceptance of Access-Based Consumption in the Case of Smartphones

Directory of Open Access Journals (Sweden)

Flora Poppelaars

2018-06-01

Full Text Available Value creation in a circular economy is based on products being returned after use. In the case of smartphones, most are never returned and tend to be kept in drawers. Smartphone access services (e.g., leasing or upgrade have been experimented with in the Netherlands but have been largely unsuccessful. This study explores the reasons why consumers rejected these access-based smartphone services and is one of the very few to address this topic. The findings are compared with the case of car access services, which are socially better accepted, to identify potential areas for improvement. The qualitative study consists of in-depth interviews with consumers (n = 18 who either adopted and used a smartphone or car access service, or had considered a new smartphone or car but did not choose access-based consumption. The findings of this small-scale study suggest that the main reasons for the rejection of smartphone access services are a lack of awareness, misunderstanding of terms and conditions, and unsatisfactory compensation for their sacrifice of not owning. Smartphone access providers could thus clearly communicate customers’ rights and responsibilities, offer an excellent service experience (especially during repair by taking over the burdens of ownership, and stimulate the societal logic shift from ownership to access.

Measurement of turbulent spatial structure and kinetic energy spectrum by exact temporal-to-spatial mapping

Science.gov (United States)

Buchhave, Preben; Velte, Clara M.

2017-08-01

We present a method for converting a time record of turbulent velocity measured at a point in a flow to a spatial velocity record consisting of consecutive convection elements. The spatial record allows computation of dynamic statistical moments such as turbulent kinetic wavenumber spectra and spatial structure functions in a way that completely bypasses the need for Taylor's hypothesis. The spatial statistics agree with the classical counterparts, such as the total kinetic energy spectrum, at least for spatial extents up to the Taylor microscale. The requirements for applying the method are access to the instantaneous velocity magnitude, in addition to the desired flow quantity, and a high temporal resolution in comparison to the relevant time scales of the flow. We map, without distortion and bias, notoriously difficult developing turbulent high intensity flows using three main aspects that distinguish these measurements from previous work in the field: (1) The measurements are conducted using laser Doppler anemometry and are therefore not contaminated by directional ambiguity (in contrast to, e.g., frequently employed hot-wire anemometers); (2) the measurement data are extracted using a correctly and transparently functioning processor and are analysed using methods derived from first principles to provide unbiased estimates of the velocity statistics; (3) the exact mapping proposed herein has been applied to the high turbulence intensity flows investigated to avoid the significant distortions caused by Taylor's hypothesis. The method is first confirmed to produce the correct statistics using computer simulations and later applied to measurements in some of the most difficult regions of a round turbulent jet—the non-equilibrium developing region and the outermost parts of the developed jet. The proposed mapping is successfully validated using corresponding directly measured spatial statistics in the fully developed jet, even in the difficult outer regions of

Neighborhood crime and access to health-enabling resources in Chicago

Directory of Open Access Journals (Sweden)

Elizabeth L. Tung

2018-03-01

Full Text Available Neighborhood crime may be an important social determinant of health in many high-poverty, urban communities, yet little is known about its relationship with access to health-enabling resources. We recruited an address-based probability sample of 267 participants (ages ≥35 years on Chicago's South Side between 2012 and 2013. Participants were queried about their perceptions of neighborhood safety and prior experiences of neighborhood crime. Survey data were paired to a comprehensive, directly-observed census of the built environment on the South Side of Chicago. Multivariable logistic regression models were used to examine access to health-enabling resources (potential and realized access as a function of neighborhood crime (self-reported neighborhood safety and prior experience of theft or property crime, adjusting for sociodemographic characteristics and self-reported health status. Low potential access was defined as a resident having nearest resources >1 mile from home; poor realized access was defined as bypassing nearby potential resources to use resources >1 mile from home. Poor neighborhood safety was associated with low potential access to large grocery stores (AOR = 1.73, 95% CI = 1.04, 2.87, pharmacies (AOR = 2.24, 95% CI = 1.33, 3.77, and fitness resources (AOR = 1.93, 95% CI = 1.15, 3.24, but not small grocery stores. Any prior experience of neighborhood crime was associated with higher adjusted odds of bypassing nearby pharmacies (AOR = 3.78, 95% CI = 1.11, 12.87. Neighborhood crime may be associated with important barriers to accessing health-enabling resources in urban communities with high rates of crime. Keywords: Built environment, Neighborhood crime, Access to resources, Social determinants of health, Obesity, Hypertension

Research on spatial structure of regional tourism resources——Taking Nanjing city as an example

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Liu Binglin

2017-08-01

Full Text Available The spatial structure of tourism resources can help to understand the spatial distribution characteristics of tourism resources,and then guide the tourism planning and improve the competitive advantage of tourism area.Based on the relevant data released by Jiangsu Provincial Tourism Bureau,taking advantage of the ArcGIS platform,the development and utilization of tourism resources and the problems in the spatial structure of tourism resources were analyzed by using the superiority index,Nearest Neighbor Index and Traffic Connectivity Index.The results show that:1 the spatial distribution of tourism resources in Nanjing is clustered;the distribution of the main urban area is relatively dense,and the resource level is higher;2 the spatial distribution of the traffic network between the tourist resources is in the middle and lower levels,and the traffic loops are poor and the accessibility is not high.The accessibility degree shows ‘center high,four weeks low’ and ‘east and west high,north and south low’.3The resource of Nanjing tourism can be optimized by optimization of the transport network;by determining the core of tourism,clarifying the level of scenic spots;increasing the efforts of tourism development and developing tourism products in depth;integration of the tourism resources,construction of the clusters and zones of tourism resources;and other aspects.

The use of spatial empirical models to estimate soil erosion in arid ecosystems.

Science.gov (United States)

Abdullah, Meshal; Feagin, Rusty; Musawi, Layla

2017-02-01

The central objective of this project was to utilize geographical information systems and remote sensing to compare soil erosion models, including Modified Pacific South-west Inter Agency Committee (MPSIAC), Erosion Potential Method (EPM), and Revised Universal Soil Loss Equation (RUSLE), and to determine their applicability for arid regions such as Kuwait. The northern portion of Umm Nigga, containing both coastal and desert ecosystems, falls within the boundaries of the de-militarized zone (DMZ) adjacent to Iraq and has been fenced off to restrict public access since 1994. Results showed that the MPSIAC and EPM models were similar in spatial distribution of erosion, though the MPSIAC had a more realistic spatial distribution of erosion and presented finer level details. The RUSLE presented unrealistic results. We then predicted the amount of soil loss between coastal and desert areas and fenced and unfenced sites for each model. In the MPSIAC and EPM models, soil loss was different between fenced and unfenced sites at the desert areas, which was higher at the unfenced due to the low vegetation cover. The overall results implied that vegetation cover played an important role in reducing soil erosion and that fencing is much more important in the desert ecosystems to protect against human activities such as overgrazing. We conclude that the MPSIAC model is best for predicting soil erosion for arid regions such as Kuwait. We also recommend the integration of field-based experiments with lab-based spatial analysis and modeling in future research.

Quantifying spatial and temporal trends in beach-dune volumetric changes using spatial statistics

Science.gov (United States)

Eamer, Jordan B. R.; Walker, Ian J.

2013-06-01

Spatial statistics are generally underutilized in coastal geomorphology, despite offering great potential for identifying and quantifying spatial-temporal trends in landscape morphodynamics. In particular, local Moran's Ii provides a statistical framework for detecting clusters of significant change in an attribute (e.g., surface erosion or deposition) and quantifying how this changes over space and time. This study analyzes and interprets spatial-temporal patterns in sediment volume changes in a beach-foredune-transgressive dune complex following removal of invasive marram grass (Ammophila spp.). Results are derived by detecting significant changes in post-removal repeat DEMs derived from topographic surveys and airborne LiDAR. The study site was separated into discrete, linked geomorphic units (beach, foredune, transgressive dune complex) to facilitate sub-landscape scale analysis of volumetric change and sediment budget responses. Difference surfaces derived from a pixel-subtraction algorithm between interval DEMs and the LiDAR baseline DEM were filtered using the local Moran's Ii method and two different spatial weights (1.5 and 5 m) to detect statistically significant change. Moran's Ii results were compared with those derived from a more spatially uniform statistical method that uses a simpler student's t distribution threshold for change detection. Morphodynamic patterns and volumetric estimates were similar between the uniform geostatistical method and Moran's Ii at a spatial weight of 5 m while the smaller spatial weight (1.5 m) consistently indicated volumetric changes of less magnitude. The larger 5 m spatial weight was most representative of broader site morphodynamics and spatial patterns while the smaller spatial weight provided volumetric changes consistent with field observations. All methods showed foredune deflation immediately following removal with increased sediment volumes into the spring via deposition at the crest and on lobes in the lee

Establishing a Secure Data Center with Remote Access: Preprint

Energy Technology Data Exchange (ETDEWEB)

Gonder, J.; Burton, E.; Murakami, E.

2012-04-01

Access to existing travel data is critical for many analysis efforts that lack the time or resources to support detailed data collection. High-resolution data sets provide particular value, but also present a challenge for preserving the anonymity of the original survey participants. To address this dilemma of providing data access while preserving privacy, the National Renewable Energy Laboratory and the U.S. Department of Transportation have launched the Transportation Secure Data Center (TSDC). TSDC data sets include those from regional travel surveys and studies that increasingly use global positioning system devices. Data provided by different collecting agencies varies with respect to formatting, elements included and level of processing conducted in support of the original purpose. The TSDC relies on a number of geospatial and other analysis tools to ensure data quality and to generate useful information outputs. TSDC users can access the processed data in two different ways. The first is by downloading summary results and second-by-second vehicle speed profiles (with latitude/longitude information removed) from a publicly-accessible website. The second method involves applying for a remote connection account to a controlled-access environment where spatial analysis can be conducted, but raw data cannot be removed.

Investigating Public Facility Characteristics from a Spatial Interaction Perspective: A Case Study of Beijing Hospitals Using Taxi Data

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Xiaoqing Kong

2017-02-01

Full Text Available Services provided by public facilities are essential to people’s lives and are closely associated with human mobility. Traditionally, public facility access characteristics, such as accessibility, equity issues and service areas, are investigated mainly based on static data (census data, travel surveys and particular records, such as medical records. Currently, the advent of big data offers an unprecedented opportunity to obtain large-scale human mobility data, which can be used to study the characteristics of public facilities from the spatial interaction perspective. Intuitively, spatial interaction characteristics and service areas of different types and sizes of public facilities are different, but how different remains an open question, so we, in turn, examine this question. Based on spatial interaction, we classify public facilities and explore the differences in facilities. In the research, based on spatial interaction extracted from taxi data, we introduce an unsupervised classification method to classify 78 hospitals in 6 districts of Beijing, and the results better reflect the type of hospital. The findings are of great significance for optimizing the spatial configuration of medical facilities or other types of public facilities, allocating public resources reasonably and relieving traffic pressure.

Spatial distributions of niche-constructing populations

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Xiaozhuo Han

2015-12-01

Full Text Available Niche construction theory regards organisms not only as the object of natural selection but also an active subject that can change their own selective pressure through eco-evolutionary feedbacks. Through reviewing the existing works on the theoretical models of niche construction, here we present the progress made on how niche construction influences genetic structure of spatially structured populations and the spatial-temporal dynamics of metapopulations, with special focuses on mathematical models and simulation methods. The majority of results confirmed that niche construction can significantly alter the evolutionary trajectories of structured populations. Organism-environmental interactions induced by niche construction can have profound influence on the dynamics, competition and diversity of metapopulations. It can affect fine-scale spatially distribution of species and spatial heterogeneity of the environment. We further propose a few research directions with potentials, such as applying adaptive dynamics or spatial game theory to explore the effect of niche construction on phenotypic evolution and diversification.

Population growth, accessibility spillovers and persistent borders: Historical growth in West-European municipalities.

Science.gov (United States)

Jacobs-Crisioni, Chris; Koomen, Eric

2017-06-01

Lack of cross-border transport supply has repeatedly been blamed for the fact that national borders limit spatial interaction and, consequently, the growth of border regions. This study applies an accessibility approach to investigate for most municipalities in ten countries in mainland West Europe if foreign transport supply is lagging behind, and if population growth in these municipalities has been affected by the limits that national borders have imposed on market access. To do so, data describing historical population changes and road networks between 1961 and 2011 have been used. The results show that in the study area, cross-border transport accessibility was not at a disadvantage in 1961 and has since then grown even more than domestic accessibility. However, municipal population growth has depended almost exclusively on domestic market access. Processes of economic international integration in the study area are found to coincide with the growth of cross-border accessibility, but do not have a clear coincidence with the effects of cross-border accessibility on population growth.

A global assessment of market accessibility and market influence for global environmental change studies

Energy Technology Data Exchange (ETDEWEB)

Verburg, Peter H [Institute for Environmental Studies, Amsterdam Global Change Institute, VU University Amsterdam, De Boelelaan 1087, 1081 HV Amsterdam (Netherlands); Ellis, Erle C [Department of Geography and Environmental Systems, University of Maryland, Baltimore County, Baltimore, MD 21250 (United States); Letourneau, Aurelien, E-mail: Peter.Verburg@ivm.vu.nl [UMR 5175 Centre d' Ecologie Fonctionnelle and Evolutive, Centre National de la Recherche Scientifique, 1919 Route de Mende, 34293 Montpellier cedex 5 (France)

2011-07-15

Markets influence the global patterns of urbanization, deforestation, agriculture and other land use systems. Yet market influence is rarely incorporated into spatially explicit global studies of environmental change, largely because consistent global data are lacking below the national level. Here we present the first high spatial resolution gridded data depicting market influence globally. The data jointly represent variations in both market strength and accessibility based on three market influence indices derived from an index of accessibility to market locations and national level gross domestic product (purchasing power parity). These indices show strong correspondence with human population density while also revealing several distinct and useful relationships with other global environmental patterns. As market influence grows, the need for high resolution global data on market influence and its dynamics will become increasingly important to understanding and forecasting global environmental change.

A global assessment of market accessibility and market influence for global environmental change studies

Science.gov (United States)

Verburg, Peter H.; Ellis, Erle C.; Letourneau, Aurelien

2011-07-01

Markets influence the global patterns of urbanization, deforestation, agriculture and other land use systems. Yet market influence is rarely incorporated into spatially explicit global studies of environmental change, largely because consistent global data are lacking below the national level. Here we present the first high spatial resolution gridded data depicting market influence globally. The data jointly represent variations in both market strength and accessibility based on three market influence indices derived from an index of accessibility to market locations and national level gross domestic product (purchasing power parity). These indices show strong correspondence with human population density while also revealing several distinct and useful relationships with other global environmental patterns. As market influence grows, the need for high resolution global data on market influence and its dynamics will become increasingly important to understanding and forecasting global environmental change.

A global assessment of market accessibility and market influence for global environmental change studies

International Nuclear Information System (INIS)

Verburg, Peter H; Ellis, Erle C; Letourneau, Aurelien

2011-01-01

Markets influence the global patterns of urbanization, deforestation, agriculture and other land use systems. Yet market influence is rarely incorporated into spatially explicit global studies of environmental change, largely because consistent global data are lacking below the national level. Here we present the first high spatial resolution gridded data depicting market influence globally. The data jointly represent variations in both market strength and accessibility based on three market influence indices derived from an index of accessibility to market locations and national level gross domestic product (purchasing power parity). These indices show strong correspondence with human population density while also revealing several distinct and useful relationships with other global environmental patterns. As market influence grows, the need for high resolution global data on market influence and its dynamics will become increasingly important to understanding and forecasting global environmental change.

The evolution of December 2004 tsunami deposits: temporal and spatial distribution of potentially toxic metalloids.

Science.gov (United States)

Kozak, Lidia; Niedzielski, Przemysław

2013-11-01

The article presents the results of research into the content of metalloid fractions in the tsunami deposits from southern Thailand. The following fractions, which are potentially most easily released from deposits to the environment, have been distinguished: the water soluble fraction, the exchangeable fraction extracted with the phosphate buffer and the fraction eluted with the solution of hydrochloric acid. The analytical technique atomic absorption spectrometry with hydride generation was applied. Spatial variability of the metalloid fractions in deposits and changes occurring in deposits over a period of several years of observation were determined. Based on the statistical analysis of the results, an attempt was made to determine the post-depositional release of deposits components to the environment. Based on the conducted research, the 4 years forming process of the arsenic, antimony and selenium occurrence after the deposition of sediments on land were described, as well as the balance in the amount of deposit components released to the environment. Copyright © 2013 Elsevier Ltd. All rights reserved.

Optical Access Networks

Science.gov (United States)

Zheng, Jun; Ansari, Nirwan

2005-01-01

Call for Papers: Optical Access Networks Guest Editors Jun Zheng, University of Ottawa Nirwan Ansari, New Jersey Institute of Technology Submission Deadline: 1 June 2005 Background With the wide deployment of fiber-optic technology over the past two decades, we have witnessed a tremendous growth of bandwidth capacity in the backbone networks of today's telecommunications infrastructure. However, access networks, which cover the "last-mile" areas and serve numerous residential and small business users, have not been scaled up commensurately. The local subscriber lines for telephone and cable television are still using twisted pairs and coaxial cables. Most residential connections to the Internet are still through dial-up modems operating at a low speed on twisted pairs. As the demand for access bandwidth increases with emerging high-bandwidth applications, such as distance learning, high-definition television (HDTV), and video on demand (VoD), the last-mile access networks have become a bandwidth bottleneck in today's telecommunications infrastructure. To ease this bottleneck, it is imperative to provide sufficient bandwidth capacity in the access networks to open the bottleneck and thus present more opportunities for the provisioning of multiservices. Optical access solutions promise huge bandwidth to service providers and low-cost high-bandwidth services to end users and are therefore widely considered the technology of choice for next-generation access networks. To realize the vision of optical access networks, however, many key issues still need to be addressed, such as network architectures, signaling protocols, and implementation standards. The major challenges lie in the fact that an optical solution must be not only robust, scalable, and flexible, but also implemented at a low cost comparable to that of existing access solutions in order to increase the economic viability of many potential high-bandwidth applications. In recent years, optical access networks

Investigation of the marked and long-standing spatial inhomogeneity of the Hungarian suicide rate: a spatial regression approach.

Science.gov (United States)

Balint, Lajos; Dome, Peter; Daroczi, Gergely; Gonda, Xenia; Rihmer, Zoltan

2014-02-01

In the last century Hungary had astonishingly high suicide rates characterized by marked regional within-country inequalities, a spatial pattern which has been quite stable over time. To explain the above phenomenon at the level of micro-regions (n=175) in the period between 2005 and 2011. Our dependent variable was the age and gender standardized mortality ratio (SMR) for suicide while explanatory variables were factors which are supposed to influence suicide risk, such as measures of religious and political integration, travel time accessibility of psychiatric services, alcohol consumption, unemployment and disability pensionery. When applying the ordinary least squared regression model, the residuals were found to be spatially autocorrelated, which indicates the violation of the assumption on the independence of error terms and - accordingly - the necessity of application of a spatial autoregressive (SAR) model to handle this problem. According to our calculations the SARlag model was a better way (versus the SARerr model) of addressing the problem of spatial autocorrelation, furthermore its substantive meaning is more convenient. SMR was significantly associated with the "political integration" variable in a negative and with "lack of religious integration" and "disability pensionery" variables in a positive manner. Associations were not significant for the remaining explanatory variables. Several important psychiatric variables were not available at the level of micro-regions. We conducted our analysis on aggregate data. Our results may draw attention to the relevance and abiding validity of the classic Durkheimian suicide risk factors - such as lack of social integration - apropos of the spatial pattern of Hungarian suicides. © 2013 Published by Elsevier B.V.

A Framework for Evaluation of Marine Spatial Data Geoportals Using Case Studies

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Tavra Marina

2014-12-01

Full Text Available Need for a Marine Spatial Data Infrastructure (MSDI as a component of a National Spatial Data Infrastructure (NSDI is widely recognized. An MSDI is relevant not only for hydrographers and government planners, but also for many other sectors which takes interest in marine spatial data, whether they are data users, data providers, or data managers [9]. An MSDI encompasses marine and coastal geographic and business information. For efficient use of Marine Spatial Data, it is necessary to ensure its valid and accessible distribution. A geoportal is a specialized web portal for sharing spatial information at different levels over the Internet. This paper re-examines the implementation of an MSDI and what it means for data custodians and end users. Several geoportals are reviewed (German and Australian to determine their web services functionality, capabilities and the scope to which they support the sharing and reuse of Marine Spatial Data to assist the development of the Croatian MSDI Geoportal. This framework provides a context for better understanding the information bases on spatial data standards and a tool for evaluation of MSDI dissemination - Geoportal.

Spatial gradient tuning in metamaterials

Science.gov (United States)

Driscoll, Tom; Goldflam, Michael; Jokerst, Nan; Basov, Dimitri; Smith, David

2011-03-01

Gradient Index (GRIN) metamaterials have been used to create devices inspired by, but often surpassing the potential of, conventional GRIN optics. The unit-cell nature of metamaterials presents the opportunity to exert much greater control over spatial gradients than is possible in natural materials. This is true not only during the design phase but also offers the potential for real-time reconfiguration of the metamaterial gradient. This ability fits nicely into the picture of transformation-optics, in which spatial gradients can enable an impressive suite of innovative devices. We discuss methods to exert control over metamaterial response, focusing on our recent demonstrations using Vanadium Dioxide. We give special attention to role of memristance and mem-capacitance observed in Vanadium Dioxide, which simplify the demands of stimuli and addressing, as well as intersecting metamaterials with the field of memory-materials.

Emerging potential for radical e-enabled improvements in rural collaboration and accessibility

CSIR Research Space (South Africa)

Naude, AH

2007-05-01

Full Text Available volumes, as well as problems associated with limited local human capacities and uncoordinated or misdirected rural development planning; and enhanced accessibility - addressing the typical problems of rural isolation such as inadequated or costly digital...

Future Trends in Vascular Access Creation.

Science.gov (United States)

Shenoy, Surendra

2017-01-01

Delivery of a prescribed dialysis dose, which is critical for longevity on hemodialysis, is directly dependent on vascular access (VA). However, VA is fraught with high failure rates and has room for innovation. Arteriovenous fistula (AVF), considered the 'best choice', has a high 'failure to mature' rate. Arteriovenous grafts (AVGs) are considered when patients are poor candidates for or have failed AVF, but have a high incidence of infections and thrombosis. Due to associated morbidity and mortality from complications, central venous catheters are considered only as 'bridging short-term access' when there is an urgent need for dialysis. The observation from current data that there is a significant center effect in the rate of AVF maturation supports investigation to identify factors that contribute to success in high-performing centers that create AVF and establish 'best practice' approaches to improve outcomes. Biocompatible AVG constructs that promote rapid tissue incorporation withstand needle punctures due to better integrity and can improve current AVG outcomes. Stenosis in the 'access circuit' is a major cause for short- and long-term permanent access failure. While the pathology of stenosis development is well understood, factors responsible for this problem are poorly studied. Increased flow in the access circuit likely plays a major role in the development of such stenosis. Investigation into understanding the hemodynamics of this flow may help identify etiology and stenosis sites perhaps even prior to the event, thus providing potential targets to mitigate the stenotic response. In summary, this chapter reflects on the shortcomings of current access modalities and discusses potential avenues to improve VA outcomes in the future. © 2017 S. Karger AG, Basel.

A study on the service radii and accessibility to health facilities in ...

African Journals Online (AJOL)

Government policies over the years has centered on the provision and delivery of healthcare to all. Spatial distribution of health facilities is subject to a number of social and commercial influences and healthcare needs of the population. The objective of this paper analyzed the service radii and accessibility of health ...

An Access Control Framework for Reflective Middleware

Institute of Scientific and Technical Information of China (English)

Gang Huang; Lian-Shan Sun

2008-01-01

Reflective middleware opens up the implementation details of middleware platform and applications at runtime for improving the adaptability of middleware-based systems. However, such openness brings new challenges to access control of the middleware-based systems.Some users can access the system via reflective entities, which sometimes cannot be protected by access control mechanisms of traditional middleware. To deliver high adaptability securely, reflective middleware should be equipped with proper access control mechanisms for potential access control holes induced by reflection. One reason of integrating these mechanisms in reflective middleware is that one goal of reflective middleware is to equip applications with reflection capabilities as transparent as possible. This paper studies how to design a reflective J2EE middlewarePKUAS with access control in mind. At first, a computation model of reflective system is built to identify all possible access control points induced by reflection. Then a set of access control mechanisms, including the wrapper of MBeans and a hierarchy of Java class loaders, are equipped for controlling the identified access control points. These mechanisms together with J2EE access control mechanism form the access control framework for PKUAS. The paper evaluates the security and the performance overheads of the framework in quality and quantity.

GEOWOW: a drought scenario for multidisciplinary data access and use

Science.gov (United States)

Santoro, Mattia; Sorichetta, Alessandro; Roglia, Elena; Craglia, Massimo; Nativi, Stefano

2013-04-01

Recent enhancements of the GEOSS Common Infrastructure (GCI; http://www.earthobservations.org/gci_gci.shtml), and in particular the introduction of a middleware in the GCI that brokers across heterogeneous information systems, have increased significantly the number of information resources discoverable worldwide. Now the challenge moves to the next level of ensuring access and use of the resources discovered, which have many different and domain-specific data models, communication protocols, encoding formats, etc. The GEOWOW Project - GEOSS interoperability for Weather, Ocean and Water, http://www.geowow.eu - developed a set of multidisciplinary use scenarios to advance the present GCI. This work describes the "Easy discovery and use of GEOSS resources for addressing multidisciplinary challenges related to drought scenarios" showcase demonstrated at the last GEO Plenary in Foz de Iguazu (Brazil). The scientific objectives of this showcase include: prevention and mitigation of water scarcity and drought situations, assessment of the population and geographical area potentially affected, evaluation of the possible distribution of mortality and economic loss risk, and support in building greater capacity to cope with drought. The need to address these challenges calls for producing scientifically robust and consistent information about the extent of land affected by drought and degradation. Similarly, in this context it is important: (i) to address uncertainties about the way in which various biological, physical, social, and economic factors interact each other and influence the occurrence of drought events, and (ii) to develop and test adequate indices and/or combination of them for monitoring and forecasting drought in different geographic locations and at various spatial scales (Brown et al., 2002). The scientific objectives above can be met with an increased interoperability across the multidisciplinary domains relevant to this drought scenario. In particular

An access to a library of novel triterpene derivatives with a promising pharmacological potential by Ugi and Passerini multicomponent reactions.

Science.gov (United States)

Wiemann, Jana; Heller, Lucie; Csuk, René

2018-04-25

The promising combination of natural product leads and their derivatization by isocyanide-based multicomponent reactions (IMCRs) has gained interest in accessing diversity-oriented libraries with auspicious pharmacological potential. Therefore, a set of 34 Ugi and 3 Passerini products was successfully synthesized starting from naturally occurring triterpenoids, i.e. oleanolic acid (OA) and maslinic acid (MA), followed by a biological evaluation of the novel α-acylamino carboxamides and the α-acyloxy carboxamides in colorimetric SRB assays to determine their cytotoxic potential. Especially, the MA-Ugi products 6a, 6b and 7b showed a remarkable cytotoxicity for A2780 ovarian carcinoma cells in a low μM range. Compounds 6a and 7b induced programmed cell death in part through the apoptosis pathway. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Spatial Lead Pollution in Aquatic Habitats and the Potential Risks in Makassar Coastal Area of South Sulawesi, Indonesia

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Anwar Mallongi

2017-11-01

Full Text Available Background: Lead can be a poison to the environment which may affects all body systems. Lead can also affect human health especially children, lead potentially lowering level of intelligence, growth, loss, causing anemia, and disorder among children as lead is neurotoxin and accumulative. In addition lead can cause a decrease in the ability of the brain, whereas in adults may cause interference of high blood pressure and other tissue toxicity. Any increase in the levels of lead in the blood of 10 ug / dl led to a decrease in IQ of 2.5 points or 0.975 IQ. The research aims to produce a special model of health risk among elementary school children due to lead exposure in the coastal city of Makassar. Methods: This study investigate the distribution of toxic lead in Makassar coastal area namely; sea water, sediments, shells  and crab. Then investigate lead toxins around the school such as lead in soil, dust, paint, snacks and air. After create distribution maps lead risks we create analysis of environmental health risks for children. Results: Result revealed that the analysis of spatial distribution of Lead in the sediment shows that the high distribution was in station 3 in Mariso districts then coastal Tallo area and the lowest was in Tamalate District. While the analysis of the spatial Pb distribution in mussels seen that the highest distribution Pb was in  station 4 of districts Mariso then coastal waters Tallo area and the lowest was in Tamalate District 5.00 to 7.20 mg / g. Conclusion: In conclusion, it revealed the concentration of Lead at all stations of those four districts have exceeded the level of allowed standard and may potentially lead to a hazard both to environment and human being who are living in the surround area.

Suspect online sellers and contraceptive access.

Science.gov (United States)

Liang, Bryan A; Mackey, Tim K; Lovett, Kimberly M

2012-11-01

Issues surrounding contraception access have been a national focus. During this debate, adolescent and adult women may seek these products online. Due to safety concerns, including potential counterfeit forms, we wished to assess whether online "no prescription" contraceptives were available. We assessed online availability of reversible, prescription contraceptive methods resulting in online pharmacy marketing is shifting from direct search engine access to social media (Facebook, Twitter, Slidehare, flickr). Online contraceptive sales represent patient safety risks and a parallel system of high-risk product access absent professional guidance. Providers should educate patients, while policy makers employ legal strategies to address these systemic risks. Copyright © 2012 Elsevier Inc. All rights reserved.

Spatial Analysis of “Crazy Quilts”, a Class of Potentially Random Aesthetic Artefacts

Science.gov (United States)

Westphal-Fitch, Gesche; Fitch, W. Tecumseh

2013-01-01

Human artefacts in general are highly structured and often display ordering principles such as translational, reflectional or rotational symmetry. In contrast, human artefacts that are intended to appear random and non symmetrical are very rare. Furthermore, many studies show that humans find it extremely difficult to recognize or reproduce truly random patterns or sequences. Here, we attempt to model two-dimensional decorative spatial patterns produced by humans that show no obvious order. “Crazy quilts” represent a historically important style of quilt making that became popular in the 1870s, and lasted about 50 years. Crazy quilts are unusual because unlike most human artefacts, they are specifically intended to appear haphazard and unstructured. We evaluate the degree to which this intention was achieved by using statistical techniques of spatial point pattern analysis to compare crazy quilts with regular quilts from the same region and era and to evaluate the fit of various random distributions to these two quilt classes. We found that the two quilt categories exhibit fundamentally different spatial characteristics: The patch areas of crazy quilts derive from a continuous random distribution, while area distributions of regular quilts consist of Gaussian mixtures. These Gaussian mixtures derive from regular pattern motifs that are repeated and we suggest that such a mixture is a distinctive signature of human-made visual patterns. In contrast, the distribution found in crazy quilts is shared with many other naturally occurring spatial patterns. Centroids of patches in the two quilt classes are spaced differently and in general, crazy quilts but not regular quilts are well-fitted by a random Strauss process. These results indicate that, within the constraints of the quilt format, Victorian quilters indeed achieved their goal of generating random structures. PMID:24066095

Equity of access to elective surgery: reflections from NZ clinicians.

Science.gov (United States)

McLeod, Deborah; Dew, Kevin; Morgan, Sonya; Dowell, Anthony; Cumming, Jackie; Cormack, Donna; McKinlay, Eileen; Love, Tom

2004-10-01

To explore factors potentially influencing equitable access to elective surgery in New Zealand by describing clinicians' perceptions of equity and the factors they consider when prioritising patients for elective surgery. A qualitative study in selected New Zealand localities. A purposive sample of 49 general practitioners, specialists and registrars were interviewed. Data were analysed thematically. General practitioners described unequal opportunities for patients to access primary and secondary care and, in particular, private sector elective surgery. They felt that socio-economically disadvantaged patients were less able to advocate for themselves and were more vulnerable to being lost to the elective surgical booking system as well as being less able to access private care. Both GPs and secondary care clinicians described situations where they would personally advocate for individual patients to improve their access. Advocacy was related to clinicians' perceptions of the 'value' that patients would receive from the surgery and patients' needs for public sector funding. The structure of the health system contributes to inequities in access to elective care in New Zealand. Subjective decision making by clinicians has the potential to advantage or disadvantage patients through the weighting clinicians place on socio-demographic factors when making rationing decisions. Review of the potential structural barriers to equitable access, further public debate and guidance for clinicians on the relative importance of socio-demographic factors in deciding access to rationed services are required for allocation of services to be fair.

Modelling the potential spatial distribution of mosquito species using three different techniques

NARCIS (Netherlands)

Cianci, D.; Hartemink, N.; Ibáñez-Justicia, A.

2015-01-01

Background: Models for the spatial distribution of vector species are important tools in the assessment of the risk of establishment and subsequent spread of vector-borne diseases. The aims of this study are to define the environmental conditions suitable for several mosquito species through species

Open Access to essential health care information

Directory of Open Access Journals (Sweden)

Pandey Manoj

2004-12-01

Full Text Available Abstract Open Access publishing is a valuable resource for the synthesis and distribution of essential health care information. This article discusses the potential benefits of Open Access, specifically in terms of Low and Middle Income (LAMI countries in which there is currently a lack of informed health care providers – mainly a consequence of poor availability to information. We propose that without copyright restrictions, Open Access facilitates distribution of the most relevant research and health care information. Furthermore, we suggest that the technology and infrastructure that has been put in place for Open Access could be used to publish download-able manuals, guides or basic handbooks created by healthcare providers in LAMI countries.

Barriers and facilitators to intraosseous access in adult resuscitations when peripheral intravenous access is not achievable.

Science.gov (United States)

James Cheung, Warren; Rosenberg, Hans; Vaillancourt, Christian

2014-03-01

Studies suggest that intraosseous (IO) access is underutilized in adult resuscitations, despite recommendations from advanced trauma and cardiac life support guidelines. The objective was to determine factors associated with IO access use by physicians during adult resuscitations when intravenous (IV) access is not immediately achievable. This study was an online survey among physicians purposefully recruited from various clinical care areas at three teaching hospitals. Questions were generated from the qualitative results of 20 iterative interviews, verified for internal validity, and piloted. The interview guide was based on the constructs of the Theory of Planned Behavior (TPB), which elicits salient attitudes, social influences, and control beliefs that potentially influence intention to use IO access. Recruitment took place in September 2012 until reaching more than 100% of the required sample size (n = 200). Internal consistency was measured using Cronbach's alpha, and the effect of TPB constructs and specific beliefs were assessed with regression analyses. For the 205 respondents, the mean age was 35 years (range = 20 to 66 years), and 53.3% were male. Participants' departmental affiliations were 50.3% emergency medicine (EM), 16.9% internal medicine, 14.9% anesthesia, 10.8% general surgery, and 7.2% critical care. Residents comprised 60.7% of the sample, and 39.3% were attending physicians. Median intention to use IO access when IV is not immediately achievable was 4.67 (interquartile range [IQR] = 4 to 5) out of 5 (5 highest) and predicted by the following TPB constructs: attitudes (AdjCoefficients = 0.504; 95% confidence interval [CI] = 0.334 to 0.673), social influences (AdjCoefficients = 0.285; 95% CI = 0.172 to 0.398), and control beliefs (AdjCoefficients 0.217; 95% CI = 0.113 to 0.320). Physicians were more likely to use IO access if they believed that it provided rapid vascular access for delivering large volumes of fluids, could prevent delays in

Access to medicines in remote and rural areas: a survey of residents in the Scottish Highlands & Western Isles.

Science.gov (United States)

Rushworth, G F; Diack, L; MacRobbie, A; Munoz, S-A; Pfleger, S; Stewart, D

2015-03-01

Sparsely populated areas are potentially predisposed to health inequalities due to limited access to services. This study aimed to explore and describe issues of access to medicines and related advice experienced by residents of the Scottish Highlands and Western Isles. Cross-sectional cohort study. Anonymized questionnaires were mailed to a random sample of 6000 residents aged ≥18 years identified from the electoral register. The questionnaire contained items on: access to medicines; interactions with health care services; and perceptions of the services. Results were analysed using descriptive, inferential and spatial statistics. Adjusted response rate was 49.5% (2913/5889). Almost two thirds (63.4%, 1847) were prescribed medicines regularly, 88.5% (1634) of whom considered the source convenient. Pharmacy (73.8%, 1364) or dispensing GP (24.0%, 443) were the most accessed sources. Prescription medicine advice was mainly obtained from the GP (55.7%, 1029). Respondents ≥80 years old were significantly (P 80 years living alone disagreed that they obtained prescribed medicines from a convenient source. The majority of respondents who felt they did not have a convenient medicines source, regardless of urban/rural classification, lived within five miles of a pharmacy or GP practice. Respondents accessed medicines and advice from a variety of sources. While most considered their access to medicines convenient, there were issues for those over 80 years and living alone. Perceived convenience would not appear to be solely based on geographical proximity to supply source. This requires further exploration given that these individuals are likely to have long-term conditions and be prescribed medicines on a chronic basis. Copyright © 2015 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

GeoCREV: veterinary geographical information system and the development of a practical sub-national spatial data infrastructure

Directory of Open Access Journals (Sweden)

Nicola Ferrè

2011-05-01

Full Text Available This paper illustrates and discusses the key issues of the geographical information system (GIS developed by the Unit of Veterinary Epidemiology of the Veneto region (CREV, defined according to user needs, spatial data (availability, accessibility and applicability, development, technical aspects, inter-institutional relationships, constraints and policies. GeoCREV, the support system for decision-making, was designed to integrate geographic information and veterinary laboratory data with the main aim to develop a sub-national, spatial data infrastructure (SDI for the veterinary services of the Veneto region in north-eastern Italy. Its implementation required (i collection of data and information; (ii building a geodatabase; and (iii development of a WebGIS application. Tools for the management, collection, validation and dissemination of the results (public access and limited access were developed. The modular concept facilitates the updating and development of the system according to user needs and data availability. The GIS management practices that were followed to develop the system are outlined, followed by a detailed discussion of the key elements of the GIS implementation process (data model, technical aspects, inter-institutional relationship, user dimension and institutional framework. Problems encountered in organising the non-spatial data and the future work directions are also described.

GeoCREV: veterinary geographical information system and the development of a practical sub-national spatial data infrastructure.

Science.gov (United States)

Ferrè, Nicola; Mulatti, Paolo; Mazzucato, Matteo; Lorenzetto, Monica; Trolese, Matteo; Pandolfo, Dario; Vio, Piero; Sitta, Guido; Marangon, Stefano

2011-05-01

This paper illustrates and discusses the key issues of the geographical information system (GIS) developed by the Unit of Veterinary Epidemiology of the Veneto region (CREV), defined according to user needs, spatial data (availability, accessibility and applicability), development, technical aspects, inter-institutional relationships, constraints and policies. GeoCREV, the support system for decision-making, was designed to integrate geographic information and veterinary laboratory data with the main aim to develop a sub-national, spatial data infrastructure (SDI) for the veterinary services of the Veneto region in north-eastern Italy. Its implementation required (i) collection of data and information; (ii) building a geodatabase; and (iii) development of a WebGIS application. Tools for the management, collection, validation and dissemination of the results (public access and limited access) were developed. The modular concept facilitates the updating and development of the system according to user needs and data availability. The GIS management practices that were followed to develop the system are outlined, followed by a detailed discussion of the key elements of the GIS implementation process (data model, technical aspects, inter-institutional relationship, user dimension and institutional framework). Problems encountered in organising the non-spatial data and the future work directions are also described.

The SPAtial EFficiency metric (SPAEF): multiple-component evaluation of spatial patterns for optimization of hydrological models

Science.gov (United States)

Koch, Julian; Cüneyd Demirel, Mehmet; Stisen, Simon

2018-05-01

The process of model evaluation is not only an integral part of model development and calibration but also of paramount importance when communicating modelling results to the scientific community and stakeholders. The modelling community has a large and well-tested toolbox of metrics to evaluate temporal model performance. In contrast, spatial performance evaluation does not correspond to the grand availability of spatial observations readily available and to the sophisticate model codes simulating the spatial variability of complex hydrological processes. This study makes a contribution towards advancing spatial-pattern-oriented model calibration by rigorously testing a multiple-component performance metric. The promoted SPAtial EFficiency (SPAEF) metric reflects three equally weighted components: correlation, coefficient of variation and histogram overlap. This multiple-component approach is found to be advantageous in order to achieve the complex task of comparing spatial patterns. SPAEF, its three components individually and two alternative spatial performance metrics, i.e. connectivity analysis and fractions skill score, are applied in a spatial-pattern-oriented model calibration of a catchment model in Denmark. Results suggest the importance of multiple-component metrics because stand-alone metrics tend to fail to provide holistic pattern information. The three SPAEF components are found to be independent, which allows them to complement each other in a meaningful way. In order to optimally exploit spatial observations made available by remote sensing platforms, this study suggests applying bias insensitive metrics which further allow for a comparison of variables which are related but may differ in unit. This study applies SPAEF in the hydrological context using the mesoscale Hydrologic Model (mHM; version 5.8), but we see great potential across disciplines related to spatially distributed earth system modelling.

Comparison of alternative spatial resolutions in the application of a spatially distributed biogeochemical model over complex terrain

Science.gov (United States)

Turner, D.P.; Dodson, R.; Marks, D.

1996-01-01

Spatially distributed biogeochemical models may be applied over grids at a range of spatial resolutions, however, evaluation of potential errors and loss of information at relatively coarse resolutions is rare. In this study, a georeferenced database at the 1-km spatial resolution was developed to initialize and drive a process-based model (Forest-BGC) of water and carbon balance over a gridded 54976 km2 area covering two river basins in mountainous western Oregon. Corresponding data sets were also prepared at 10-km and 50-km spatial resolutions using commonly employed aggregation schemes. Estimates were made at each grid cell for climate variables including daily solar radiation, air temperature, humidity, and precipitation. The topographic structure, water holding capacity, vegetation type and leaf area index were likewise estimated for initial conditions. The daily time series for the climatic drivers was developed from interpolations of meteorological station data for the water year 1990 (1 October 1989-30 September 1990). Model outputs at the 1-km resolution showed good agreement with observed patterns in runoff and productivity. The ranges for model inputs at the 10-km and 50-km resolutions tended to contract because of the smoothed topography. Estimates for mean evapotranspiration and runoff were relatively insensitive to changing the spatial resolution of the grid whereas estimates of mean annual net primary production varied by 11%. The designation of a vegetation type and leaf area at the 50-km resolution often subsumed significant heterogeneity in vegetation, and this factor accounted for much of the difference in the mean values for the carbon flux variables. Although area wide means for model outputs were generally similar across resolutions, difference maps often revealed large areas of disagreement. Relatively high spatial resolution analyses of biogeochemical cycling are desirable from several perspectives and may be particularly important in the

Developmental changes in visuo-spatial working memory in normally developing children: event-related potentials study.

Science.gov (United States)

Myatchin, Ivan; Lagae, Lieven

2013-10-01

Working memory (WM) is very important for normal development. The fronto-parietal neuronal network supporting WM has already been well-studied. Less is known about the cortical activity changes during development of WM. We evaluated the maturation of visual WM network at the electrophysiological level in a group of normally developing children. Multichannel (n=31) event-related potentials (ERP) were measured during a visuo-spatial backmatching task in 69 childrens (6-16 years old). One-backmatching (BM1) and two-backmatching (BM2) tasks were performed. Age-related changes in behavioral parameters (commission and omission errors and reaction times) and ERP parameters (peak amplitudes and latencies) were analyzed between different ages. Clear improvement in performance from young childhood toward adolescence was seen at the behavioral level: decrease of errors and fastening of reaction times. At the electrophysiological level age-related changes were seen in peak latencies and especially in amplitudes. Different peaks have different dynamics in amplitudes and latencies: early peak amplitude decreased and latency shortened with age, which was not always seen in late peaks. This reflects developmental changes in intensity and speed of WM processing. Later peaks were more clearly seen over the right hemisphere in older children, illustrating hemispheric lateralization in visuo-spatial working memory. Our results indicate that not only at the behavioral but also at the electrophysiological level clear age-related dynamics in WM processing can be seen. Furthermore, with ERP we showed that different WM components follow different developmental trajectories. Our work demonstrates that age-related dynamics in intensity and speed of information processing during WM task is reflected in developmental changes in different ERP components. It also states that fronto-parietal visual WM network can be functional even before all its nodes are fully mature. Copyright © 2012 The

A potential spatial working memory training task to improve both episodic memory and fluid intelligence.

Directory of Open Access Journals (Sweden)

Sarah R Rudebeck

Full Text Available One current challenge in cognitive training is to create a training regime that benefits multiple cognitive domains, including episodic memory, without relying on a large battery of tasks, which can be time-consuming and difficult to learn. By giving careful consideration to the neural correlates underlying episodic and working memory, we devised a computerized working memory training task in which neurologically healthy participants were required to monitor and detect repetitions in two streams of spatial information (spatial location and scene identity presented simultaneously (i.e. a dual n-back paradigm. Participants' episodic memory abilities were assessed before and after training using two object and scene recognition memory tasks incorporating memory confidence judgments. Furthermore, to determine the generalizability of the effects of training, we also assessed fluid intelligence using a matrix reasoning task. By examining the difference between pre- and post-training performance (i.e. gain scores, we found that the trainers, compared to non-trainers, exhibited a significant improvement in fluid intelligence after 20 days. Interestingly, pre-training fluid intelligence performance, but not training task improvement, was a significant predictor of post-training fluid intelligence improvement, with lower pre-training fluid intelligence associated with greater post-training gain. Crucially, trainers who improved the most on the training task also showed an improvement in recognition memory as captured by d-prime scores and estimates of recollection and familiarity memory. Training task improvement was a significant predictor of gains in recognition and familiarity memory performance, with greater training improvement leading to more marked gains. In contrast, lower pre-training recollection memory scores, and not training task improvement, led to greater recollection memory performance after training. Our findings demonstrate that practice

Investigating the Potential of Using the Spatial and Spectral Information of Multispectral LiDAR for Object Classification

Directory of Open Access Journals (Sweden)

Wei Gong

2015-09-01

Full Text Available The abilities of multispectral LiDAR (MSL as a new high-potential active instrument for remote sensing have not been fully revealed. This study demonstrates the potential of using the spectral and spatial features derived from a novel MSL to discriminate surface objects. Data acquired with the MSL include distance information and the intensities of four wavelengths at 556, 670, 700, and 780 nm channels. A support vector machine was used to classify diverse objects in the experimental scene into seven types: wall, ceramic pots, Cactaceae, carton, plastic foam block, and healthy and dead leaves of E. aureum. Different features were used during classification to compare the performance of different detection systems. The spectral backscattered reflectance of one wavelength and distance represented the features from an equivalent single-wavelength LiDAR system; reflectance of the four wavelengths represented the features from an equivalent multispectral image with four bands. Results showed that the overall accuracy of using MSL data was as high as 88.7%, this value was 9.8%–39.2% higher than those obtained using a single-wavelength LiDAR, and 4.2% higher than for multispectral image.

Applications of seismic spatial wavefield gradient and rotation data in exploration seismology

Science.gov (United States)

Schmelzbach, C.; Van Renterghem, C.; Sollberger, D.; Häusler, M.; Robertsson, J. O. A.

2017-12-01

Seismic spatial wavefield gradient and rotation data have the potential to open up new ways to address long-standing problems in land-seismic exploration such as identifying and separating P-, S-, and surface waves. Gradient-based acquisition and processing techniques could enable replacing large arrays of densely spaced receivers by sparse spatially-compact receiver layouts or even one single multicomponent station with dedicated instruments (e.g., rotational seismometers). Such approaches to maximize the information content of single-station recordings are also of significant interest for seismic measurements at sites with limited access such as boreholes, the sea bottom, and extraterrestrial seismology. Arrays of conventional three-component (3C) geophones enable measuring not only the particle velocity in three dimensions but also estimating their spatial gradients. Because the free-surface condition allows to express vertical derivatives in terms of horizontal derivatives, the full gradient tensor and, hence, curl and divergence of the wavefield can be computed. In total, three particle velocity components, three rotational components, and divergence, result seven-component (7C) seismic data. Combined particle velocity and gradient data can be used to isolate the incident P- or S-waves at the land surface or the sea bottom using filtering techniques based on the elastodynamic representation theorem. Alternatively, as only S-waves exhibit rotational motion, rotational measurements can directly be used to identify S-waves. We discuss the derivations of the gradient-based filters as well as their application to synthetic and field data, demonstrating that rotational data can be of particular interest to S-wave reflection and P-to-S-wave conversion imaging. The concept of array-derived gradient estimation can be extended to source arrays as well. Therefore, source arrays allow us to emulate rotational (curl) and dilatational (divergence) sources. Combined with 7C

Planning of spatial development of tourism based on the example of spatial plan of Subotica municipality

Directory of Open Access Journals (Sweden)

Šećerov Velimir

2008-01-01

Full Text Available Planning of tourism development and its spatial disposition in Europe and world today are an important segment of the overall economic development. Having in mind its important economic and social functions, as well as its capability to intensify its other economic branches (agricultural and economic potentials, services of various types, transport and other in a certain territory, it is necessary to realize a precise valorization of tourist values in the spatial plan of municipality and to conclude at what point and at which places the tourism can represent on of development components of the entire economy of the territory to be planed. The example of the spatial plan of Subotica and main guidelines, concept and planning priorities which can be expected in the forthcoming period are presented in this paper. It is without any doubt that the municipality of Subotica with its geostrategic position, the proximity of the EU and important natural and cultural tourist potentials is a suitable space for application of contemporary principles of the tourism development planning and their correlation with other segments of integral development for the whole municipality.

GIS and remote sensing components of a spatial decision system in support of sustainable forest management

Energy Technology Data Exchange (ETDEWEB)

St-Onge, B.A.; Waaub, J.P.; Alleaume, S.; Couture, M. [Quebec Univ., Dept. of Geography, Montreal, PQ (Canada)

1999-05-01

The development of a tool used in decision making processes in forest management was discussed with special focus on two critical aspects of the decision aid system which pertain to spatial information. These are: (1) the use of up-to-date precise information, and (2) the accessibility of this information. This paper focuses on two approaches designed to provide accessible high quality information to the users of the decision aid system: i.e. the development of high resolution remote sensing methods, and a GIS data warehouse accessible over the Internet. 4 refs., 2 figs.

Explaining the evaporation paradox in Jiangxi Province of China: Spatial distribution and temporal trends in potential evapotranspiration of Jiangxi Province from 1961 to 2013

Directory of Open Access Journals (Sweden)

Xianghui Lu

2016-03-01

Full Text Available Evaporation acts as an important component and a key control factor in land hydrological processes. In order to analyze the trend of change on potential evapotranspiration from 1961 to 2013 and to discuss the existence of the evaporation paradox in Jiangxi province, China, monthly meteorological data spanning the years 1961–2013 were analyzed in this study, where the data were collected from 15 national meteorological stations in Jiangxi Province. The Penman–Monteith equation was employed to compute the potential evapotranspiration (ET0. Spatial interpolation and data mining technology were used to analyze the spatial and temporal changes of ET0 and air temperature, with the effort to explain the evaporation paradox. By solving the total differential and the partial derivatives coefficients of the independent variables in Penman–Monteith equation, the cause of the paradox was quantitatively evaluated. The results showed that the annual ET0 had been decreasing significantly in Jiangxi Province since 1979, whereas the air temperature had been rising significantly, presenting the evaporation paradox. The decreases in sunshine duration and wind speed reduced ET0 by 0.207 mm and 0.060 mm, respectively, accounting for 92.3% and 26.7% of the total ET0, respectively. It is concluded that sunshine duration and wind speed are the main causes to the decrease in potential evapotranspiration in Jiangxi Province.

A contextual ICA stakeholder model approach for the Namibian spatial data infrastructure (NamSDI)

CSIR Research Space (South Africa)

Sinvula, KM

2013-08-01

Full Text Available In 2011, the Namibian parliament presented and promulgated the Namibian Spatial Data Infrastructure (NamSDI) with the aim of promoting the sharing and improved access and use of geospatial data and services across Namibia. Notable SDI models...

The Energy-Water Nexus: Spatially-Resolved Analysis of the Potential for Desalinating Brackish Groundwater by Use of Solar Energy

Directory of Open Access Journals (Sweden)

Jill B. Kjellsson

2015-06-01

Full Text Available This research looks at coupling desalination with renewable energy sources to create a high-value product (treated water from two low value resources (brackish groundwater and intermittent solar energy. Desalination of brackish groundwater is already being considered as a potential new water supply in Texas. This research uses Texas as a testbed for spatially-resolved analysis techniques while considering depth to brackish groundwater, water quality, and solar radiation across Texas to determine the locations with the best potential for integrating solar energy with brackish groundwater desalination. The framework presented herein can be useful for policymakers, regional planners, and project developers as they consider where to site desalination facilities coupled with solar photovoltaics. Results suggest that the northwestern region of Texas—with abundant sunshine and groundwater at relatively shallow depths and low salinity in areas with freshwater scarcity—has the highest potential for solar powered desalination. The range in capacity for solar photovoltaic powered reverse osmosis desalination was found to be 1.56 × 10—6 to 2.93 × 10—5 cubic meters of water per second per square meter of solar panel (m3/s/m2.

Action potential influences spatial perception: Evidence for genuine top-down effects on perception.

Science.gov (United States)

Witt, Jessica K

2017-08-01

The action-specific account of spatial perception asserts that a perceiver's ability to perform an action, such as hitting a softball or walking up a hill, impacts the visual perception of the target object. Although much evidence is consistent with this claim, the evidence has been challenged as to whether perception is truly impacted, as opposed to the responses themselves. These challenges have recently been organized as six pitfalls that provide a framework with which to evaluate the empirical evidence. Four case studies of action-specific effects are offered as evidence that meets the framework's high bar, and thus that demonstrates genuine perceptual effects. That action influences spatial perception is evidence that perceptual and action-related processes are intricately and bidirectionally linked.

The effects of CCK-8S on spatial memory and long-term potentiation at CA1 during induction of stress in rats.

Science.gov (United States)

Sadeghi, Malihe; Reisi, Parham; Radahmadi, Maryam

2017-12-01

Cholecystokinin (CCK) has been proposed as a mediator in stress. However, it is still not fully documented what are its effects. We aimed to evaluate the effects of systemic administration of CCK exactly before induction of stress on spatial memory and synaptic plasticity at CA1 in rats. Male Wistar rats were divided into 4 groups: the control, the control-CCK, the stress and the stress-CCK. Restraint stress was induced 6 hr per day, for 24 days. Cholecystokinin sulfated octapeptide (CCK-8S) was injected (1.6 µg/kg, IP) before each session of stress induction. Spatial memory was evaluated by Morris water maze test. Long-term potentiation (LTP) in Schaffer collateral-CA1 synapses was assessed (by 100 Hz tetanization) in order to investigate synaptic plasticity. Stress impaired spatial memory significantly ( P stress group. With respect to the control group, both fEPSP amplitude and slope were significantly ( P stress group. However, there were no differences between responses of the control-CCK and Stress-CCK groups compared to the control group. The present results suggest that high levels of CCK-8S during induction of stress can modulate the destructive effects of stress on hippocampal synaptic plasticity and memory. Therefore, the mediatory effects of CCK in stress are likely as compensatory responses.

Spatial forecast of landslides in three gorges based on spatial data mining.

Science.gov (United States)

Wang, Xianmin; Niu, Ruiqing

2009-01-01

The Three Gorges is a region with a very high landslide distribution density and a concentrated population. In Three Gorges there are often landslide disasters, and the potential risk of landslides is tremendous. In this paper, focusing on Three Gorges, which has a complicated landform, spatial forecasting of landslides is studied by establishing 20 forecast factors (spectra, texture, vegetation coverage, water level of reservoir, slope structure, engineering rock group, elevation, slope, aspect, etc). China-Brazil Earth Resources Satellite (Cbers) images were adopted based on C4.5 decision tree to mine spatial forecast landslide criteria in Guojiaba Town (Zhigui County) in Three Gorges and based on this knowledge, perform intelligent spatial landslide forecasts for Guojiaba Town. All landslides lie in the dangerous and unstable regions, so the forecast result is good. The method proposed in the paper is compared with seven other methods: IsoData, K-Means, Mahalanobis Distance, Maximum Likelihood, Minimum Distance, Parallelepiped and Information Content Model. The experimental results show that the method proposed in this paper has a high forecast precision, noticeably higher than that of the other seven methods.

Towards a Spatial Understanding of Trade-Offs in Sustainable Development: A Meso-Scale Analysis of the Nexus between Land Use, Poverty, and Environment in the Lao PDR

Science.gov (United States)

Messerli, Peter; Bader, Christoph; Hett, Cornelia; Epprecht, Michael; Heinimann, Andreas

2015-01-01

In land systems, equitably managing trade-offs between planetary boundaries and human development needs represents a grand challenge in sustainability oriented initiatives. Informing such initiatives requires knowledge about the nexus between land use, poverty, and environment. This paper presents results from Lao PDR, where we combined nationwide spatial data on land use types and the environmental state of landscapes with village-level poverty indicators. Our analysis reveals two general but contrasting trends. First, landscapes with paddy or permanent agriculture allow a greater number of people to live in less poverty but come at the price of a decrease in natural vegetation cover. Second, people practising extensive swidden agriculture and living in intact environments are often better off than people in degraded paddy or permanent agriculture. As poverty rates within different landscape types vary more than between landscape types, we cannot stipulate a land use–poverty–environment nexus. However, the distinct spatial patterns or configurations of these rates point to other important factors at play. Drawing on ethnicity as a proximate factor for endogenous development potentials and accessibility as a proximate factor for external influences, we further explore these linkages. Ethnicity is strongly related to poverty in all land use types almost independently of accessibility, implying that social distance outweighs geographic or physical distance. In turn, accessibility, almost a precondition for poverty alleviation, is mainly beneficial to ethnic majority groups and people living in paddy or permanent agriculture. These groups are able to translate improved accessibility into poverty alleviation. Our results show that the concurrence of external influences with local—highly contextual—development potentials is key to shaping outcomes of the land use–poverty–environment nexus. By addressing such leverage points, these findings help guide more

A global map of travel time to cities to assess inequalities in accessibility in 2015

Science.gov (United States)

Weiss, D. J.; Nelson, A.; Gibson, H. S.; Temperley, W.; Peedell, S.; Lieber, A.; Hancher, M.; Poyart, E.; Belchior, S.; Fullman, N.; Mappin, B.; Dalrymple, U.; Rozier, J.; Lucas, T. C. D.; Howes, R. E.; Tusting, L. S.; Kang, S. Y.; Cameron, E.; Bisanzio, D.; Battle, K. E.; Bhatt, S.; Gething, P. W.

2018-01-01

The economic and man-made resources that sustain human wellbeing are not distributed evenly across the world, but are instead heavily concentrated in cities. Poor access to opportunities and services offered by urban centres (a function of distance, transport infrastructure, and the spatial distribution of cities) is a major barrier to improved livelihoods and overall development. Advancing accessibility worldwide underpins the equity agenda of ‘leaving no one behind’ established by the Sustainable Development Goals of the United Nations. This has renewed international efforts to accurately measure accessibility and generate a metric that can inform the design and implementation of development policies. The only previous attempt to reliably map accessibility worldwide, which was published nearly a decade ago, predated the baseline for the Sustainable Development Goals and excluded the recent expansion in infrastructure networks, particularly in lower-resource settings. In parallel, new data sources provided by Open Street Map and Google now capture transportation networks with unprecedented detail and precision. Here we develop and validate a map that quantifies travel time to cities for 2015 at a spatial resolution of approximately one by one kilometre by integrating ten global-scale surfaces that characterize factors affecting human movement rates and 13,840 high-density urban centres within an established geospatial-modelling framework. Our results highlight disparities in accessibility relative to wealth as 50.9% of individuals living in low-income settings (concentrated in sub-Saharan Africa) reside within an hour of a city compared to 90.7% of individuals in high-income settings. By further triangulating this map against socioeconomic datasets, we demonstrate how access to urban centres stratifies the economic, educational, and health status of humanity.

A global map of travel time to cities to assess inequalities in accessibility in 2015.

Science.gov (United States)

Weiss, D J; Nelson, A; Gibson, H S; Temperley, W; Peedell, S; Lieber, A; Hancher, M; Poyart, E; Belchior, S; Fullman, N; Mappin, B; Dalrymple, U; Rozier, J; Lucas, T C D; Howes, R E; Tusting, L S; Kang, S Y; Cameron, E; Bisanzio, D; Battle, K E; Bhatt, S; Gething, P W

2018-01-18

The economic and man-made resources that sustain human wellbeing are not distributed evenly across the world, but are instead heavily concentrated in cities. Poor access to opportunities and services offered by urban centres (a function of distance, transport infrastructure, and the spatial distribution of cities) is a major barrier to improved livelihoods and overall development. Advancing accessibility worldwide underpins the equity agenda of 'leaving no one behind' established by the Sustainable Development Goals of the United Nations. This has renewed international efforts to accurately measure accessibility and generate a metric that can inform the design and implementation of development policies. The only previous attempt to reliably map accessibility worldwide, which was published nearly a decade ago, predated the baseline for the Sustainable Development Goals and excluded the recent expansion in infrastructure networks, particularly in lower-resource settings. In parallel, new data sources provided by Open Street Map and Google now capture transportation networks with unprecedented detail and precision. Here we develop and validate a map that quantifies travel time to cities for 2015 at a spatial resolution of approximately one by one kilometre by integrating ten global-scale surfaces that characterize factors affecting human movement rates and 13,840 high-density urban centres within an established geospatial-modelling framework. Our results highlight disparities in accessibility relative to wealth as 50.9% of individuals living in low-income settings (concentrated in sub-Saharan Africa) reside within an hour of a city compared to 90.7% of individuals in high-income settings. By further triangulating this map against socioeconomic datasets, we demonstrate how access to urban centres stratifies the economic, educational, and health status of humanity.

Transport, Acceleration and Spatial Access of Solar Energetic Particles

Science.gov (United States)

Borovikov, D.; Sokolov, I.; Effenberger, F.; Jin, M.; Gombosi, T. I.

2017-12-01

Solar Energetic Particles (SEPs) are a major branch of space weather. Often driven by Coronal Mass Ejections (CMEs), SEPs have a very high destructive potential, which includes but is not limited to disrupting communication systems on Earth, inflicting harmful and potentially fatal radiation doses to crew members onboard spacecraft and, in extreme cases, to people aboard high altitude flights. However, currently the research community lacks efficient tools to predict such hazardous SEP events. Such a tool would serve as the first step towards improving humanity's preparedness for SEP events and ultimately its ability to mitigate their effects. The main goal of the presented research is to develop a computational tool that provides the said capabilities and meets the community's demand. Our model has the forecasting capability and can be the basis for operational system that will provide live information on the current potential threats posed by SEPs based on observations of the Sun. The tool comprises several numerical models, which are designed to simulate different physical aspects of SEPs. The background conditions in the interplanetary medium, in particular, the Coronal Mass Ejection driving the particle acceleration, play a defining role and are simulated with the state-of-the-art MHD solver, Block-Adaptive-Tree Solar-wind Roe-type Upwind Scheme (BATS-R-US). The newly developed particle code, Multiple-Field-Line-Advection Model for Particle Acceleration (M-FLAMPA), simulates the actual transport and acceleration of SEPs and is coupled to the MHD code. The special property of SEPs, the tendency to follow magnetic lines of force, is fully taken advantage of in the computational model, which substitutes a complicated 3-D model with a multitude of 1-D models. This approach significantly simplifies computations and improves the time performance of the overall model. Also, it plays an important role of mapping the affected region by connecting it with the origin of

Coastal fog and low cloud spatial patterns: do they indicate potential biodiversity refugia?

Science.gov (United States)

Torregrosa, A.

2016-12-01

Marine fog and low clouds transfer water and nutrients to coastal ecosystems through advection from the ocean and reduce heat effects by reflecting incoming shortwave radiation. These effects are known to benefit many species, vegetation communities, and habitats such as coastal redwood trees and their understory, maritime chaparral, and coastal streams harboring endangered salmon species. The California floristic region is the highest ranked hotspot in the U.S. and ranked 7th of 35 biodiversity hotspots worldwide in terms of the percent of its plant species that are found nowhere else (endemic). Many environmental drivers have been identified as contributing to California's remarkably high endemism and biodiversity, however, coastal low clouds have not typically been included. This could be due to the lack of data such as high resolution maps of coastal low cloud occurrence or the lack of long term records. Using a recent analysis of hourly National Weather Service satellite data, a stability index (SI) for coastal fog and low cloud cover was derived using two measures of variation and average summertime cloud cover to quantify long term spatial stability trends. Several discrete spatial clumps were identified that had both high temporal stability and high coastal low cloud cover. These areas show a strong correlation with a specific topographic landscape configuration with respect to wind direction. Point occurrence distribution maps of endemic coastal species were overlain with the SI to explore spatial correlation. The federally endangered species that showed very high spatial correlation included Yadon's Rein-orchid (Piperia yadonii), Monterey Spineflower (Chorizanthe pungens var. pungens), and Seaside Bird's-beak (Cordylanthus rigidus ssp. littoralis). Current estimated range maps are not consistent with the SI results suggesting a need to update estimated ranges. Biodiversity measures are being investigated in these areas to explore the hypothesis that they

Single-photon three-qubit quantum logic using spatial light modulators.

Science.gov (United States)

Kagalwala, Kumel H; Di Giuseppe, Giovanni; Abouraddy, Ayman F; Saleh, Bahaa E A

2017-09-29

The information-carrying capacity of a single photon can be vastly expanded by exploiting its multiple degrees of freedom: spatial, temporal, and polarization. Although multiple qubits can be encoded per photon, to date only two-qubit single-photon quantum operations have been realized. Here, we report an experimental demonstration of three-qubit single-photon, linear, deterministic quantum gates that exploit photon polarization and the two-dimensional spatial-parity-symmetry of the transverse single-photon field. These gates are implemented using a polarization-sensitive spatial light modulator that provides a robust, non-interferometric, versatile platform for implementing controlled unitary gates. Polarization here represents the control qubit for either separable or entangling unitary operations on the two spatial-parity target qubits. Such gates help generate maximally entangled three-qubit Greenberger-Horne-Zeilinger and W states, which is confirmed by tomographical reconstruction of single-photon density matrices. This strategy provides access to a wide range of three-qubit states and operations for use in few-qubit quantum information processing protocols.Photons are essential for quantum information processing, but to date only two-qubit single-photon operations have been realized. Here the authors demonstrate experimentally a three-qubit single-photon linear deterministic quantum gate by exploiting polarization along with spatial-parity symmetry.

SCOAP3 and Open Access

CERN Document Server

Mele, Salvatore; D'Agostino, Dan; Dyas-Correia, Sharon

2009-01-01

SCOAP3 is an innovative Open Access initiative for publishing in high-energy physics. The model is viewed by many as a potential solution to multiple issues related to the financial crisis, the peer review system, scholarly communication, and the need to support institutional repositories. This installment of “The Balance Point” presents articles written by three Open Access advocates, outlining the SCOAP3 proposal, benefits of participation, and some of the roles libraries, publishers and scientists can play in making important changes to scholarly communication. Contributors discuss scalability and transferability issues of SCOAP3, as well as other matters of concern.

Transportation Accessibility and Location Choice of Japanese-Funded Electronic Information Manufacturing Firms in Shanghai

Directory of Open Access Journals (Sweden)

Haining Jiang

2018-02-01

Full Text Available With the rapid development of globalization, information communication and transportation, it is argued that the effect of transportation accessibility in the location choice of manufacturing firms has diminished. However, comprehensive and systematic research on the impact of transportation accessibility on firm location choice in cities remains scarce. Taking Shanghai as the research area, this paper uses a catalog of Japanese-funded electronic information manufacturing firms to explore the influence of transportation accessibility on their location choice. The paper first describes firm distribution using the nuclear density estimation method. The Poisson regression model is then used to estimate the significance of transportation accessibility in influencing firm location. The empirical results show that most of the firms are concentrated in the inner suburbs of Shanghai, with only a small number in the outer suburban areas. The spatial coupling relationship between firm distribution and transportation accessibility is significant. These firms tend to choose areas with good accessibility to transportation infrastructure, and, in particular, the effect of airport accessibility is significant. Compared with the joint venture enterprises, wholly-owned Japanese enterprises are more inclined to be in areas with better transportation accessibility.

A smarter way to search, share and utilize open-spatial online data for energy R&D - Custom machine learning and GIS tools in U.S. DOE's virtual data library & laboratory, EDX

Science.gov (United States)

Rose, K.; Bauer, J.; Baker, D.; Barkhurst, A.; Bean, A.; DiGiulio, J.; Jones, K.; Jones, T.; Justman, D.; Miller, R., III; Romeo, L.; Sabbatino, M.; Tong, A.

2017-12-01

As spatial datasets are increasingly accessible through open, online systems, the opportunity to use these resources to address a range of Earth system questions grows. Simultaneously, there is a need for better infrastructure and tools to find and utilize these resources. We will present examples of advanced online computing capabilities, hosted in the U.S. DOE's Energy Data eXchange (EDX), that address these needs for earth-energy research and development. In one study the computing team developed a custom, machine learning, big data computing tool designed to parse the web and return priority datasets to appropriate servers to develop an open-source global oil and gas infrastructure database. The results of this spatial smart search approach were validated against expert-driven, manual search results which required a team of seven spatial scientists three months to produce. The custom machine learning tool parsed online, open systems, including zip files, ftp sites and other web-hosted resources, in a matter of days. The resulting resources were integrated into a geodatabase now hosted for open access via EDX. Beyond identifying and accessing authoritative, open spatial data resources, there is also a need for more efficient tools to ingest, perform, and visualize multi-variate, spatial data analyses. Within the EDX framework, there is a growing suite of processing, analytical and visualization capabilities that allow multi-user teams to work more efficiently in private, virtual workspaces. An example of these capabilities are a set of 5 custom spatio-temporal models and data tools that form NETL's Offshore Risk Modeling suite that can be used to quantify oil spill risks and impacts. Coupling the data and advanced functions from EDX with these advanced spatio-temporal models has culminated with an integrated web-based decision-support tool. This platform has capabilities to identify and combine data across scales and disciplines, evaluate potential environmental

Spatial statistics detect clustering patterns of kidney diseases in south-eastern Romania

Directory of Open Access Journals (Sweden)

Ruben I.

2016-02-01

Full Text Available Medical geography was conceptualized almost ten years ago due to its obvious usefulness in epidemiological research. Still, numerous diseases in many regions were neglected in these aspects of research, and the prevalence of kidney diseases in Eastern Europe is such an example. We evaluated the spatial patterns of main kidney diseases in south-eastern Romania, and highlighted the importance of spatial modeling in medical management in Romania. We found two statistically significant hotspots of kidney diseases prevalence. We also found differences in the spatial patterns between categories of diseases. We propose to speed up the process of creating a national database of records on kidney diseases. Offering the researchers access to a national database will allow further epidemiology studies in Romania and finally lead to a better management of medical services.

A three-stage heuristic for harvest scheduling with access road network development

Science.gov (United States)

Mark M. Clark; Russell D. Meller; Timothy P. McDonald

2000-01-01

In this article we present a new model for the scheduling of forest harvesting with spatial and temporal constraints. Our approach is unique in that we incorporate access road network development into the harvest scheduling selection process. Due to the difficulty of solving the problem optimally, we develop a heuristic that consists of a solution construction stage...

Accessible solitons of fractional dimension

Energy Technology Data Exchange (ETDEWEB)

Zhong, Wei-Ping, E-mail: zhongwp6@126.com [Department of Electronic and Information Engineering, Shunde Polytechnic, Guangdong Province, Shunde 528300 (China); Texas A& M University at Qatar, P.O. Box 23874, Doha (Qatar); Belić, Milivoj [Texas A& M University at Qatar, P.O. Box 23874, Doha (Qatar); Zhang, Yiqi [Key Laboratory for Physical Electronics and Devices of the Ministry of Education & Shaanxi Key Lab of Information Photonic Technique, Xi’an Jiaotong University, Xi’an 710049 (China)

2016-05-15

We demonstrate that accessible solitons described by an extended Schrödinger equation with the Laplacian of fractional dimension can exist in strongly nonlocal nonlinear media. The soliton solutions of the model are constructed by two special functions, the associated Legendre polynomials and the Laguerre polynomials in the fraction-dimensional space. Our results show that these fractional accessible solitons form a soliton family which includes crescent solitons, and asymmetric single-layer and multi-layer necklace solitons. -- Highlights: •Analytic solutions of a fractional Schrödinger equation are obtained. •The solutions are produced by means of self-similar method applied to the fractional Schrödinger equation with parabolic potential. •The fractional accessible solitons form crescent, asymmetric single-layer and multilayer necklace profiles. •The model applies to the propagation of optical pulses in strongly nonlocal nonlinear media.

The importance of spatial accuracy in characterizing stand types ...

African Journals Online (AJOL)

This study assessed the potential use of Landsat 7 ETM+ (15 and 30 m spatial resolutions) images to estimate forest stand attributes such as development stages, crown closure and stand types. The study evaluates the performance of spatial and image classification accuracies between Landsat images (15 and 30 m ...

The Mission Accessibility of Near-Earth Asteroids

Science.gov (United States)

Barbee, Brent W.; Abell, P. A.; Adamo, D. R.; Mazanek, D. D.; Johnson, L. N.; Yeomans, D. K.; Chodas, P. W.; Chamberlin, A. B.; Benner, L. A. M.; Taylor, P.;

Cognitive Access to TVWS in India

DEFF Research Database (Denmark)

Patil, Kishor P.; Skouby, Knud Erik; Prasad, Ramjee

2013-01-01

The digital transition of TV transmission will make available some TV frequencies which are to be geographically unused called as TV White Spaces. The important regulatory trend in the context of Dynamic Spectrum Access (DSA) is the Cognitive access of TV white Spaces. In this context, we have pe...... of India, we have proposed wireless broadband access to rural areas using TV White Spaces (TVWSs). This will help in bridging the digital divide by offering governance, banking, and health services online in the rural areas.......The digital transition of TV transmission will make available some TV frequencies which are to be geographically unused called as TV White Spaces. The important regulatory trend in the context of Dynamic Spectrum Access (DSA) is the Cognitive access of TV white Spaces. In this context, we have...... performed spectrum measurements of TV band in Pune, India. Our result shows poor spectrum utilization in TV band, and good potential for Cognitive radio operation. Digital switchover in India will generate golden opportunity for empowering rural India. As majority of India’s population lives in rural part...

Survey on composition and bioconcentration potential of 12 metallic elements in King Bolete (Boletus edulis) mushroom that emerged at 11 spatially distant sites.

Science.gov (United States)

Falandysz, Jerzy; Frankowska, Aneta; Jarzynska, Grazyna; Dryzałowska, Anna; Kojta, Anna K; Zhang, Dan

2011-01-01

This paper provides data on baseline concentrations, interrelationships and bioconcentration potential of 12 metallic elements by King Bolete collected from 11 spatially distant sites across Poland. There are significant differences in concentrations of metals (Al, Ba, Ca, Cd, Cu, Fe, K, Mg, Mn, Na, Sr, Zn) and their bioconcentration potential in King Bolete Boletus edulis at 11 spatially distant sites surveyed across Poland. These have resulted from significant geographical differences in trace metal concentrations in a layer (0-10 cm) of organic and mineral soil underneath to fruiting bodies and possible local bioavailabilities of macro- (Ca, K, Mg, Na) and trace metals (Al, Ba, Cd, Cu, Fe, Mn, Sr, Zn) to King Bolete. The use of highly appreciated wild-grown edible King Bolete mushroom has established a baseline measure of regional minerals status, heavy metals pollution and assessment of intake rates for wild mushroom dish fanciers against which future changes can be compared. Data on Cd, Cu and Zn from this study and from literature search can be useful to set the maximum limit of these metals in King Bolete collected from uncontaminated (background) areas. In this report also reviewed are data on Al, Ba, Ca, Cd, Cu, Fe, K, Mg, Mn, Na, Sr and Zn accumulation in King Bolete.

Collisions of Two Spatial Solitons in Inhomogeneous Nonlinear Media

International Nuclear Information System (INIS)

Zhong Weiping; Yi Lin; Yang Zhengping; Xie Ruihua; Milivoj, Belic; Chen Goong

2008-01-01

Collisions of spatial solitons occurring in the nonlinear Schroeinger equation with harmonic potential are studied, using conservation laws and the split-step Fourier method. We find an analytical solution for the separation distance between the spatial solitons in an inhomogeneous nonlinear medium when the light beam is self-trapped in the transverse dimension. In the self-focusing nonlinear media the spatial solitons can be transmitted stably, and the interaction between spatial solitons is enhanced due to the linear focusing effect (and also diminished for the linear defocusing effect). In the self-defocusing nonlinear media, in the absence of self-trapping or in the presence of linear self-defocusing, no transmission of stable spatial solitons is possible. However, in such media the linear focusing effect can be exactly compensated, and the spatial solitons can propagate through

Spatial filtring and thermocouple spatial filter

International Nuclear Information System (INIS)

Han Bing; Tong Yunxian

1989-12-01

The design and study on thermocouple spatial filter have been conducted for the flow measurement of integrated reactor coolant. The fundamental principle of spatial filtring, mathematical descriptions and analyses of thermocouple spatial filter are given

Impact of Megacity Jobs-Housing Spatial Mismatch on Commuting Behaviors: A Case Study on Central Districts of Shanghai, China

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Xiang Zhou

2016-01-01

Full Text Available This studyutilized the mobile signaling data to conductthe impact analysis of jobs-housing spatial mismatch on commuting behavior, with eight typical employment centers of three categories selected as the research subjects. Based on the analysis of the characteristics and indictors including commuting distance, accessibilities from cumulative opportunity model etc., this study demonstrates that (a cumulative percentage of short commuting distance (e.g., less than 3 km reflects the jobs-housing spatial match between employment centers and their peripheral areas; and (b combining the indicators of employed population and area covered within a certain space-time range among indictors of accessibility, it is possible to identify the degree of jobs-housing balance and efficiency of the transport system. According to the evaluation radar maps, the authors believe that employment centers could be divided into three categories: those with a gathering power, those with improvable functions, and those with local adjustment potentials. Possible measures including controlling the gathering power of the city centers, improving the function mix and transport facilities, and optimizing the overall local environment, etc. could be made to achieve jobs-housing balance in central districts and their peripheral areas as a whole. Besides, the study, proceeding from the perspective of commuters, suggests that optimization of jobs-housing distribution along banded corridors would be more efficient than those within the traditional region so as to reduce commuting traffic load.

Interoperable and accessible census and survey data from IPUMS.

Science.gov (United States)

Kugler, Tracy A; Fitch, Catherine A

2018-02-27

The first version of the Integrated Public Use Microdata Series (IPUMS) was released to users in 1993, and since that time IPUMS has come to stand for interoperable and accessible census and survey data. Initially created to harmonize U.S. census microdata over time, IPUMS now includes microdata from the U.S. and international censuses and from surveys on health, employment, and other topics. IPUMS also provides geo-spatial data, aggregate population data, and environmental data. IPUMS supports ten data products, each disseminating an integrated data collection with a set of tools that make complex data easy to find, access, and use. Key features are record-level integration to create interoperable datasets, user-friendly interfaces, and comprehensive metadata and documentation. The IPUMS philosophy aligns closely with the FAIR principles of findability, accessibility, interoperability, and re-usability. IPUMS data have catalyzed knowledge generation across a wide range of social science and other disciplines, as evidenced by the large volume of publications and other products created by the vast IPUMS user community.

Particle data management-turning data into accessible information

International Nuclear Information System (INIS)

Bonniface, J; Coppins, G J

2007-01-01

The UKAEA has assigned significant resources to the monitoring and retrieval of particles from the vicinity of its site at Dounreay in the north of Scotland. The monitoring, retrieval and analytical processes each generate information that is required for interpretative and record purposes. As significant resources are made available for studying and retrieving particles, the information collected must be managed in a logical, stable and accessible manner to protect the investment in information. If suitable data management procedures are not in place there is a high risk of data loss and duplication, and stakeholders may be unable to discover what information is already available or be unable to access the existing information. UKAEA Dounreay operates a geographic information system (GIS) that interfaces with a data management system known as IMAGES. These systems are used to securely store and access a wide range of environmental data including those relating to particles. A case study is presented illustrating the processes and systems involved with the collection, storage, analysis and distribution of particle data. The advantages gained through use of the GIS system are considered in relation to alternative types of record management system such as paper, and electronic non-spatial systems. It is considered that the GIS system offers very significant benefits in terms of standardisation of data capture, security of storage and increased accessibility of data compared with other systems

Automated identification of potential snow avalanche release areas based on digital elevation models

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Y. Bühler

2013-05-01

Full Text Available The identification of snow avalanche release areas is a very difficult task. The release mechanism of snow avalanches depends on many different terrain, meteorological, snowpack and triggering parameters and their interactions, which are very difficult to assess. In many alpine regions such as the Indian Himalaya, nearly no information on avalanche release areas exists mainly due to the very rough and poorly accessible terrain, the vast size of the region and the lack of avalanche records. However avalanche release information is urgently required for numerical simulation of avalanche events to plan mitigation measures, for hazard mapping and to secure important roads. The Rohtang tunnel access road near Manali, Himachal Pradesh, India, is such an example. By far the most reliable way to identify avalanche release areas is using historic avalanche records and field investigations accomplished by avalanche experts in the formation zones. But both methods are not feasible for this area due to the rough terrain, its vast extent and lack of time. Therefore, we develop an operational, easy-to-use automated potential release area (PRA detection tool in Python/ArcGIS which uses high spatial resolution digital elevation models (DEMs and forest cover information derived from airborne remote sensing instruments as input. Such instruments can acquire spatially continuous data even over inaccessible terrain and cover large areas. We validate our tool using a database of historic avalanches acquired over 56 yr in the neighborhood of Davos, Switzerland, and apply this method for the avalanche tracks along the Rohtang tunnel access road. This tool, used by avalanche experts, delivers valuable input to identify focus areas for more-detailed investigations on avalanche release areas in remote regions such as the Indian Himalaya and is a precondition for large-scale avalanche hazard mapping.

Automated identification of potential snow avalanche release areas based on digital elevation models

Science.gov (United States)

Bühler, Y.; Kumar, S.; Veitinger, J.; Christen, M.; Stoffel, A.; Snehmani

2013-05-01

The identification of snow avalanche release areas is a very difficult task. The release mechanism of snow avalanches depends on many different terrain, meteorological, snowpack and triggering parameters and their interactions, which are very difficult to assess. In many alpine regions such as the Indian Himalaya, nearly no information on avalanche release areas exists mainly due to the very rough and poorly accessible terrain, the vast size of the region and the lack of avalanche records. However avalanche release information is urgently required for numerical simulation of avalanche events to plan mitigation measures, for hazard mapping and to secure important roads. The Rohtang tunnel access road near Manali, Himachal Pradesh, India, is such an example. By far the most reliable way to identify avalanche release areas is using historic avalanche records and field investigations accomplished by avalanche experts in the formation zones. But both methods are not feasible for this area due to the rough terrain, its vast extent and lack of time. Therefore, we develop an operational, easy-to-use automated potential release area (PRA) detection tool in Python/ArcGIS which uses high spatial resolution digital elevation models (DEMs) and forest cover information derived from airborne remote sensing instruments as input. Such instruments can acquire spatially continuous data even over inaccessible terrain and cover large areas. We validate our tool using a database of historic avalanches acquired over 56 yr in the neighborhood of Davos, Switzerland, and apply this method for the avalanche tracks along the Rohtang tunnel access road. This tool, used by avalanche experts, delivers valuable input to identify focus areas for more-detailed investigations on avalanche release areas in remote regions such as the Indian Himalaya and is a precondition for large-scale avalanche hazard mapping.

Spatial Cognition and Range Use in Free-Range Laying Hens.

Science.gov (United States)

Campbell, Dana L M; Talk, Andrew C; Loh, Ziyang A; Dyall, Tim R; Lee, Caroline

2018-02-08

Radio-frequency identification tracking shows individual free-range laying hens vary in range use, with some never going outdoors. The range is typically more environmentally complex, requiring navigation to return to the indoor resources. Outdoor-preferring hens may have improved spatial abilities compared to indoor-preferring hens. Experiment 1 tested 32 adult ISA Brown hens in a T-maze learning task that showed exclusively-indoor birds were slowest to reach the learning success criterion ( p 0.05), the age that coincided with the onset of lay. Enriched birds that were faster to learn the maze task showed more range visits in the first 4 weeks of range access. Enriched and non-enriched birds showed no differences in telencephalon or hippocampal volume ( p > 0.05). Fear may reduce spatial abilities but further testing with more pen replicates per early rearing treatments would improve our understanding of the relationship between spatial cognitive abilities and range use.

Spatial Representation of Ordinal Information

Directory of Open Access Journals (Sweden)

Meng eZhang

2016-04-01

Full Text Available Right hand responds faster than left hand when shown larger numbers and vice-versa when shown smaller numbers (the SNARC effect. Accumulating evidence suggests that the SNARC effect may not be exclusive for numbers and can be extended to other ordinal sequences (e.g., months or letters in the alphabet as well. In this study, we tested the SNARC effect with a non-numerically ordered sequence: The Chinese notations for the color spectrum (Red, Orange, Yellow, Green, Blue, Indigo, and Violet. Chinese color word sequence reserves relatively weak ordinal information, because each element color in the sequence normally appears in non-sequential contexts, making it ideal to test the spatial organization of sequential information that was stored in the long-term memory. This study found a reliable SNARC-like effect for Chinese color words (deciding whether the presented color word was before or after the reference color word green, suggesting that, without access to any quantitative information or exposure to any previous training, ordinal representation can still activate a sense of space. The results support that weak ordinal information without quantitative magnitude encoded in the long-term memory can activate spatial representation in a comparison task.

Spatial Representation of Ordinal Information.

Science.gov (United States)

Zhang, Meng; Gao, Xuefei; Li, Baichen; Yu, Shuyuan; Gong, Tianwei; Jiang, Ting; Hu, Qingfen; Chen, Yinghe

2016-01-01

Right hand responds faster than left hand when shown larger numbers and vice-versa when shown smaller numbers (the SNARC effect). Accumulating evidence suggests that the SNARC effect may not be exclusive for numbers and can be extended to other ordinal sequences (e.g., months or letters in the alphabet) as well. In this study, we tested the SNARC effect with a non-numerically ordered sequence: the Chinese notations for the color spectrum (Red, Orange, Yellow, Green, Blue, Indigo, and Violet). Chinese color word sequence reserves relatively weak ordinal information, because each element color in the sequence normally appears in non-sequential contexts, making it ideal to test the spatial organization of sequential information that was stored in the long-term memory. This study found a reliable SNARC-like effect for Chinese color words (deciding whether the presented color word was before or after the reference color word "green"), suggesting that, without access to any quantitative information or exposure to any previous training, ordinal representation can still activate a sense of space. The results support that weak ordinal information without quantitative magnitude encoded in the long-term memory can activate spatial representation in a comparison task.

Manifest Spatialization: Militarizing Communication in Canada

Directory of Open Access Journals (Sweden)

Patricia Mazepa

2015-06-01

Full Text Available Focusing on the political economy of communication and the process of spatialization whereby control over space and time is extended through the use of information and communication technology (ICT, this paper provides an overview of the intersections that draw the Canadian federal government, its military, and the ICT, defence and security industries into relationships that reinforce and extend their control. By attending to historical and current examples, it highlights several sub-processes of spatialization, including corporate restructuring (through vertical and horizontal integration, as well as state restructuring (principally through internationalization and commercialization, which together underpin and support the militarization of communication. From the state’s concentration on conventional war and the “Cold War”, through to the current “War on Terror” and its protection of an integrated ICT infrastructure, communication is increasingly confined within a narrow militarized and corporatized framework. Within this framework, both capital and the military prioritize the development and administration of the “command and control” capabilities of ICT, such that the policies and practices of communication become more exclusive, restrictive and surveilled, and less open, accessible, and universal. The paper seeks to explain how this tripartite combination of “command, control, and communication” is indicative of the process of spatialization, and supports a militarized capitalism and the formation of a cross-border MICC poised to expand and defend it.

Potential of grass seed production for new lawns

Directory of Open Access Journals (Sweden)

Josiane Vargas de Oliveira Maximino

2017-07-01

Full Text Available The Paspalum and Axonopus genera are among the main warm season grasses used for lawns. The seed propagation contributes to the decrease of the cost of establishment, besides maintaining the exact characteristics of the mother plant genotype, because they are apomictic species. The objective of this work was to evaluate the seed production potential of seventeen grass accesses of the species Paspalum notatum, P. lepton, P. lividum and Axonopus parodii. The experiment was conducted at Capão do Leão, Rio Grande do Sul State, Brazil, in a randomized block design, with four replications. The evaluated variables were: number of inflorescences per area, number of florets per inflorescence and seed production potential (SPP. In order to measure the seed production potential of the accesses, the equation proposed is: SPP = number of florets per inflorescence x number of inflorescences per m2 . There were year, access and interaction between years and accesses effect for the traits number of inflorescences per area and seed production potential. For the number of florets per inflorescence, there was no year effect. Potential production for the 2013/2014 harvest, ranged from 19,152.00 to 135,062.70 seeds m- ², with PN 09 of the P. notatum species standing out. In the 2014/2015 harvest, the seed production potential ranged from 9,973.75 to 81,536.75 seeds m- ², highlighting the access PN 11 of the species P. notatum. The accesses PN 11, PN 09, PN 10 and AP 01 were in the top third of the seed production potential ranking in the two harvests, and “grama-batatais” was in the lower third. There is genotype-environment interaction for all characteristics evaluated. However, there are accesses that show seed production potential consistently superior to the “grama-batatais” control, and have a greater potential for exploitation in the establishment of lawns by seeds.

Spatial cognition and science achievement: The contribution of intrinsic and extrinsic spatial skills from 7 to 11 years.

Science.gov (United States)

Hodgkiss, Alex; Gilligan, Katie A; Tolmie, Andrew K; Thomas, Michael S C; Farran, Emily K

2018-01-22

Prior longitudinal and correlational research with adults and adolescents indicates that spatial ability is a predictor of science learning and achievement. However, there is little research to date with primary-school aged children that addresses this relationship. Understanding this association has the potential to inform curriculum design and support the development of early interventions. This study examined the relationship between primary-school children's spatial skills and their science achievement. Children aged 7-11 years (N = 123) completed a battery of five spatial tasks, based on a model of spatial ability in which skills fall along two dimensions: intrinsic-extrinsic; static-dynamic. Participants also completed a curriculum-based science assessment. Controlling for verbal ability and age, mental folding (intrinsic-dynamic spatial ability), and spatial scaling (extrinsic-static spatial ability) each emerged as unique predictors of overall science scores, with mental folding a stronger predictor than spatial scaling. These spatial skills combined accounted for 8% of the variance in science scores. When considered by scientific discipline, mental folding uniquely predicted both physics and biology scores, and spatial scaling accounted for additional variance in biology and variance in chemistry scores. The children's embedded figures task (intrinsic-static spatial ability) only accounted for variance in chemistry scores. The patterns of association were consistent across the age range. Spatial skills, particularly mental folding, spatial scaling, and disembedding, are predictive of 7- to 11-year-olds' science achievement. These skills make a similar contribution to performance for each age group. © 2018 The Authors. British Journal of Education Psychology published by John Wiley & Sons Ltd on behalf of British Psychological Society.

Spatial analyses of benthic habitats to define coral reef ecosystem regions and potential biogeographic boundaries along a latitudinal gradient.

Directory of Open Access Journals (Sweden)

Brian K Walker

Full Text Available Marine organism diversity typically attenuates latitudinally from tropical to colder climate regimes. Since the distribution of many marine species relates to certain habitats and depth regimes, mapping data provide valuable information in the absence of detailed ecological data that can be used to identify and spatially quantify smaller scale (10 s km coral reef ecosystem regions and potential physical biogeographic barriers. This study focused on the southeast Florida coast due to a recognized, but understudied, tropical to subtropical biogeographic gradient. GIS spatial analyses were conducted on recent, accurate, shallow-water (0-30 m benthic habitat maps to identify and quantify specific regions along the coast that were statistically distinct in the number and amount of major benthic habitat types. Habitat type and width were measured for 209 evenly-spaced cross-shelf transects. Evaluation of groupings from a cluster analysis at 75% similarity yielded five distinct regions. The number of benthic habitats and their area, width, distance from shore, distance from each other, and LIDAR depths were calculated in GIS and examined to determine regional statistical differences. The number of benthic habitats decreased with increasing latitude from 9 in the south to 4 in the north and many of the habitat metrics statistically differed between regions. Three potential biogeographic barriers were found at the Boca, Hillsboro, and Biscayne boundaries, where specific shallow-water habitats were absent further north; Middle Reef, Inner Reef, and oceanic seagrass beds respectively. The Bahamas Fault Zone boundary was also noted where changes in coastal morphologies occurred that could relate to subtle ecological changes. The analyses defined regions on a smaller scale more appropriate to regional management decisions, hence strengthening marine conservation planning with an objective, scientific foundation for decision making. They provide a framework

Hazard tolerance of spatially distributed complex networks

International Nuclear Information System (INIS)

Dunn, Sarah; Wilkinson, Sean

2017-01-01

In this paper, we present a new methodology for quantifying the reliability of complex systems, using techniques from network graph theory. In recent years, network theory has been applied to many areas of research and has allowed us to gain insight into the behaviour of real systems that would otherwise be difficult or impossible to analyse, for example increasingly complex infrastructure systems. Although this work has made great advances in understanding complex systems, the vast majority of these studies only consider a systems topological reliability and largely ignore their spatial component. It has been shown that the omission of this spatial component can have potentially devastating consequences. In this paper, we propose a number of algorithms for generating a range of synthetic spatial networks with different topological and spatial characteristics and identify real-world networks that share the same characteristics. We assess the influence of nodal location and the spatial distribution of highly connected nodes on hazard tolerance by comparing our generic networks to benchmark networks. We discuss the relevance of these findings for real world networks and show that the combination of topological and spatial configurations renders many real world networks vulnerable to certain spatial hazards. - Highlights: • We develop a method for quantifying the reliability of real-world systems. • We assess the spatial resilience of synthetic spatially distributed networks. • We form algorithms to generate spatial scale-free and exponential networks. • We show how these “synthetic” networks are proxies for real world systems. • Conclude that many real world systems are vulnerable to spatially coherent hazard.

Infectious Intestinal Diseases and Residential Water Services in Mexico: a Spatial Analysis

Directory of Open Access Journals (Sweden)

Nicholas P. Sisto

2017-09-01

Full Text Available Infectious intestinal diseases (IID represent a widespread public health problem in Mexico. The country also faces major challenges with respect to the provision of residential water services (piped water and sewer—an essential input for hygiene and cleanliness in homes. This paper analyzes morbidity rates from several IID associated with unsanitary living conditions along with a series of residential water services indicators for Mexico’s 2,456 municipalities. With data obtained through a special request to the federal epidemiological authority as well as official census data for 2010, we find stark regional contrasts and identify interesting spatial structures for both IID morbidity and residential water services indicators. In particular, municipalities tend to present values similar to neighboring municipalities, forming clusters of relatively high-value (or low-value municipalities. Moreover we find that municipalities with a relatively high level of access to residential water services tend to present relatively low IID morbidity rates. These results have multiple public policy implications. In order to reduce the incidence of IID effectively and efficiently, interventions should explicitly consider the spatial structure of morbidity and target problem spots—which typically spill over state, municipal and other administrative boundaries. Moreover, improvements in the quality of access to piped water (for example, increasing the frequency of supply may be as important for reducing morbidity as the expansion of basic access to this service.