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 20 of 55 for “"patchiness"”.
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Application of synchronisation theory to plankton patchiness
… shows that persistent spatial heterogeneity (patchiness) can result from what intuitively should be a homogenising influence: mixing can increase the level of disorder between the plankton populations. Furthermore, the work shows that synchronisation effects occur generically under a range of …
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Existence of patchiness in constricted lungs : from experiments to complex system modeling
… closure of airways and the emergence of patchiness hypothesized to occur during an asthma attack. Second, from High-Resolution Computed Tomography (HRCT) images of the lung, the effect of longitudinal heterogeneity on resistance to airflow within central airways was studied. Lastly, the …
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Distribution, patchiness, and behavior of Antarctic zooplankton, assessed using multi-frequency acoustic techniques
… forces that drive zooplankton distribution and patchiness in an antarctic continental shelf region were examined, with particular emphasis on the Antarctic krill, Euphausia superba. This was accomplished by the application of acoustic, video, and environmental sensors during surveys of the …
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Distribution, patchiness, and behavior of Antarctic zooplankton, assessed using multi-frequency acoustic techniques
… forces that drive zooplankton distribution and patchiness in an antarctic continental shelf region were examined, with particular emphasis on the Antarctic krill, Euphausia superba. This was accomplished by the application of acoustic, video, and environmental sensors during surveys of the …
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Within-fire patchiness associated with prescribed burning in the northern Jarrah forests of Western Australia
… However, there is limited information on the patchiness (spatial configuration of unburnt and burnt patches which occur at a range of spatial scales) within the perimeter of a single prescribed burn. Of particular concern is the idea that prescribed burning operations, carried out under very …
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Phytoplankton in flow
… the potential for turbulent shear to produce patchiness in the spatial distribution of motile phytoplankton. Field measurements have revealed that motile phytoplankton form aggregations at the smallest scales of marine turbulence - the Kolmogorov scale (typically millimeters to centimeters) - …
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Dynamics of marine zooplankton : social behavior, ecological interactions, and physically-induced variability
… processes that contribute to the observed patchiness. The evolution of social behavior is simulated in a theoretical framework that includes zooplankton population dynamics, swimming behavior, and some aspects of the variability inherent to fluid environments. First, I formulate a model of …
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Water use of forests along elevation gradients in the Berchtesgaden National Park
… two alternative hypotheses, namely that stomatal patchiness as well as carboxylation capacity (Vcmax) may have had an influence on stand water use. The modelled transpiration with changes in Vcmax was similar to estimated transpiration rates obtained by changing the “portion of leaves that are …
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Dynamics of marine zooplankton : social behavior ecological interactions, and physically-induced variability
… processes that contribute to the observed patchiness. The evolution of social behavior is simulated in a theoretical framework that includes zooplankton population dynamics, swimming behavior, and some aspects of the variability inherent to fluid environments. First, I formulate a model of …
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Ultrasound features of human carotid plaques
… We introduced a novel feature, namely plaque patchiness, describing the pattern of the plaque as being more or less spotty on the ultrasound image. Subjects with the combination of echolucent and spotty plaques had increased values of weight, body mass index, waist and hip. Since echolucency …
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A model of copepod population dynamics in the southern Benguela upwelling region
… was investigated by assuming that spatial patchiness affected the degree of overlap between zooplankton and phytoplankton populations. The effect of spatial patchiness is particularly prevalent under poor feeding conditions, and may result in predictions based on average feeding conditions …
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The spatial and temporal abundance patterns of chaetognaths in the western North Atlantic Ocean
… which bias the abundance estimates, and patchiness and subsampling, which add variability to the abundance estimates. The 0.333 mm mesh of the MOCNESS does not appear to sample individuals of any of the species less than 6 mm in length very well. Avoidance appears to be a problem only for …
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Benthic mineralization and microscale heterogeneity
… number of avenues for future work on microscale patchiness. This<br/>especially includes; I) Plant and microorganism effects on rhizosphere biogeochemistry; II) Microscale heterogeneity of microbial abundance, diversity and function; III) Fauna induced microscale heterogeneity and structure.
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Early Life History of <i>Prognichtys occidentalis</i> and <i>Caranx crysos</i> Associated With <i>Sargassus</i> Habitat in the Northcentral Gulf of Mexico
… in the results were likely caused by prey patchiness in the oceanic environment and suggests that Sargassum and associated fronts provide conditions for increased growth, feeding, and condition for many larval and young juvenile fishes.</p>
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A novel non-invasive optical method for quantitative visualization of pH and oxygen dynamics in soils
… roots, layers or macropores enhance the patchiness of these distributions. At the same time it is difficult to access the spatial distribution and temporal dynamics of these parameter. Noninvasive imaging techniques with high spatial and temporal resolution overcome these limitations. And …
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Aquatic microenvironments in bacterial ecology and diversity
… or particles. Finally, the microscale patchiness of bacterial cells was examined over an annual cycle, revealing seasonal variation and a positive correlation with eukaryotic cell number, suggesting that bacteria may cluster in the nutrient-rich microzones around algae in the …
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Spatial Distribution and Stock-Recruitment Analysis of the Atlantic Surfclam, <i>Spisula solidissima</i>, in the Mid-Atlantic Bight and on Georges Bank
… molluscs with dispersive larval stages. Surfclam patchiness throughout the U.S. Exclusive Economic Zone (EEZ) has declined from the 1980’s to the present in all assessed regions (Delmarva, New Jersey, Long Island, Southern New England, and Georges Banks). Warming of Mid-Atlantic bottom waters is …
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Egg and larval ecology of anchovy (Engraulis capensis) and sardine (Sardinops sagax) in the Southern Benguela ecosystem
… observed from one season to the next. Lloyd's Patchiness Index was used to investigate the distribution patterns of spawning products and the results showed that the distribution of both anchovy and sardine eggs and larvae was extremely patchy, but that the eggs of both species were more patchy …
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A model of the temporal and spatial distribution of carbon monoxide in the mixed layer
… CO budget may be subject to spatial and temporal patchiness.
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Mechanistic models of recruitment variability in fish populations.
… in the timing of peak food abundance, and the patchiness of the prey, on recruitment variability. The idea of non-constant variance in recruitment is also investigated, with the aim of testing its practical relevance to fisheries management. It is demonstrated that the currently available …
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