Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 17 of 17 for “"distance decay"”.
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Measuring Accessibility to Primary Health Care Across the Urban-rural Continuum in the Province of Alberta
… exist. While many studies attempted to include a distance decay function to address local travel patterns, it is usually arbitrary and may not exactly reflect the reality. This project is an attempt to improve the current methodology and make it more suitable for provincial settings that include …
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Commuting flows & local labour markets: Spatial interaction modelling of travel-to-work
… commuting, this thesis shows that in addition to distance and working population size, the spatial structure of origins and destinations and a number of non-spatial attributes such as unemployment, housing density, and education, all signi�- cantly a�ect commuting ows. Furthermore, the distance …
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The Macroecology of Microorganisms: From Pattern to Process
… classic macroecological patterns, such as the distance-decay of similarity, are context-dependent and vary according to ecological context, and methodological differences. I therefore make recommendations for future analyses of spatial analyses of microbial communities. Furthermore, I show that …
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Investigating Health Inequality in Primary Care Spatial Accessibility Among Races and Ethnicities in King County Using a Geospatial Approach
Distance to healthcare providers is a significant barrier to health care access in the U.S. Healthcare utilization and disease burden have been found to increase as the distance between patients and primary care physicians increase. Although spatial accessibility to primary care resources has been …
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The Effect of Spatial and Environmental Drivers on Patterns in Species Richness and Composition
… thesis demonstrates that scale dependencies in distance-decay analyses cannot be traced back to processes that are specific for the ecological scale, but can largely be attributed to sampling design and are highly sensitive to grain size and study extent. Distance-decay analyses are an adequate …
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Measuring Accessibility to Primary Care Physicians in the Nashville Metropolitan Statistical Area
… In addition, this research implemented several distance-decay functions in addition to the dichotomous function of the standard 2SFCA method. This research has found that the majority of the population residing in the Nashville MSA enjoyed good spatial accessibility to PCPs. However, the highest …
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Geographic barriers to early breast cancer detection in central Illinois
… late stage breast cancer. The maps show a clear distance decay pattern with the highest concentration of patients living in Champaign-Urbana near the main Carle hospital facility. A possible cluster of late-stage cases was observed in Villa Grove, IL, but this is most likely just a random …
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Community ecology of aquatic insects in forested headwater streams in the southern Appalachians
… headwater streams in the southern Appalachians. Distance decay in taxonomic and functional similarity was used to determine the scales at which taxonomic turnover occurred within functional niches. Trait-neutral models of community composition were used as null models to assess which functional …
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DENSITY BASED FRAMEWORKS FOR SPATIO-TEMPORAL CHANGE ANALYSIS
… to be an efficient tool to model the distance-decay effect, we developed new density-based collocation measures estimating the strength of a given collocation pattern in a particular location. This approach is generalized to 3D spatio-temporal space to mine spatio-temporal collocation …
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Effects of nutrient limitation on understory communities in a tropical forest
… dissertation compares composition variation and decay-rates between terrestrial ferns and understory palms, since the extent to which their resource needs overlap has not been determined. Furthermore, ferns and palms are two essential components of forest understories that differ widely in …
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Phylometagenomics: a new framework for uncovering microbial community diversity
… statistics, which operate on pair-wise distance matrices. My analyses demonstrate that use of these methods, by reducing a highly-dimensional data set (tens of samples, thousands of OTUs), results in a significant loss of information. I demon- strate that, in some cases, up to 80% of the …
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Exotic Species Invasion and Biodiversity in Bangladesh Forest Ecosystems
… at breast height for each individual tree. Distance-decay approach was applied to analyze the spatial pattern of biodiversity for the whole study area and two subsamples from Satchari National Park and Satchari Reserve Forest. Analyses showed that biomass increased significantly with …
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Place as Occupational Histories: Towards an Understanding of Deflated Surface Artefact Distributions in the West Darling, New South Wales, Australia
… wider lithic landscape. In general, there is a distance decay relationship in the reduction of silcrete. This relationship is not evident in all measures of reduction intensity. Variation in measures of core reduction is interpreted to reflect the variable nature of occupation through time at …
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The Effect of Environmental Perturbations on the Plant Phyllosphere Microbiome
Applying ecological concepts to microbial communities has proved to be challenging, often revolving around the relative importance of stochastic and deterministic processes applied heterogeneously across the habitat in time or space. The phyllosphere is the aboveground surface of plants on which …
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The geographical data science of population flows
… of rurality on the propensity to travel greater distances; the impact of a stronger employment market area on the reluctance to travel and finally the effect of increased religious differences between home and workplace on a reduced willingness to travel further. The spatial structure of the …
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Impact of Spatial Distance and Pollinators on Floral and Fruit Bacterial Communities of Solanum carolinense
… There have been limited studies on how spatial distance influences bacterial communities found in and on fruit tissue and the role of pollinators in shaping floral bacterial communities. The first study addresses how bacterial communities in fruit change across similar environmental conditions …
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Examining the Modifiable Areal Unit Problem: Associations Between Surface Mining and Birth Outcomes in Central Appalachia at Multiple Spatial Scales
Health studies often rely on aggregated instead of individual-level data to protect patient privacy. However, aggregated data are subject to the modifiable areal unit problem (MAUP), meaning results of statistical analyses may differ depending on the data's scale and areal unit. Past studies have …