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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
171

Mediators of Fine-Scale Population Genetic Structure in the Black Blow Fly, Phormia regina (Meigen) (Diptera: Calliphoridae)

Owings, Charity Grace 08 1900 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Population genetic structure is difficult to assess in blow flies (Diptera: Calliphoridae) due to high connectivity and genetic diversity of subpopulations. Previous studies revealed high relatedness among individuals within wild samples of blow fly populations, however broad geographic structure was absent. The aim of this research was to determine if blow fly genetic structure exists at a fine spatiotemporal resolution and, if so, to elucidate the influence of environmental factors and resource availability on fly genetics. Specifically, blow fly population genetic patterns were tested against a null hypothesis that flies adhere to a patchy population model with high genetic diversity (i.e. no structure) and high resource availability. Samples of the black blow fly, Phormia regina Meigen (Diptera: Calliphoridae), were collected at six urban parks in Indiana, USA (=urban) in 2016 and 2017 (N = 14 and 16 timepoints, respectively). Additional sampling in different ecoregions was performed to determine if trends observed at a high-resolution scale were also present at a broad geographic scale. Therefore, P. regina were also collected at four sites within two national parks (the Great Smoky Mountains and Yellowstone National Parks) over a three-day period. Randomly selected females (N = 10) from each sample underwent the following analyses: 1) gut DNA extraction, 2) molecular analysis at 6 microsatellite loci, 3) vertebrate-specific 12S and 16S rRNA sequencing, and, 4) vertebrate fecal metabolite screening. Flies from the national parks and a comparable subset of urban data also underwent stable isotope analysis (SIA) to determine larval food source. Overall, strong seasonal population genetic structure was observed over both years in the urban environment (2016 F’ST = 0.47, 2017 F’ST 0.34), however spatial structure was lacking, as seen in previous studies (2016 F’ST = 0.04, 2017 F’ST 0.03). Weather conditions prior to and on the day of blow fly collections, interspecific competition, and resource availability greatly impacted the genetic diversity and kinship of P. regina. A total of 17 and 19 vertebrate species were detected by flies in 2016 and 2017, respectively, and many flies tested positive for vertebrate feces, suggesting that many varied resources are important for maintaining high gene flow among geographic locations. Genetic diversity was non-existent in flies collected from the Smokies (F’ST = 0.00), while very slight spatial structure existed in the Yellowstone populations (F’ST = 0.07). Environmental factors such as temperature, humidity, and wind speed were all statistically relevant in maximizing fly collections with vertebrate resources. In 720 min of total sampling time in the national parks and a subset of urban data, 28 vertebrate species were identified, and fecal resources appeared to be the most abundant in Yellowstone. Stable isotope analysis revealed a majority of larval resources in the national parks were herbivores, with a more even distribution of carnivore and herbivore carcasses present in the urban environment, which likely explains the high genetic diversity of adult flies in these regions. Overall, the null hypothesis that P. regina adheres to a patchy population model could not be rejected for the Smokies populations. However, the urban and Yellowstone populations appear to adhere to a Levins metapopulation model in which variable availability in resources leads to random bottleneck events in the local populations. Overall, environmental conditions, competition, and resource availability are all important factors influencing P. regina population genetic structure in different environments.
172

Average Taxonomic Distinctness as a Measure of Global Biodiversity

Tunison, Robert January 2018 (has links)
No description available.
173

A hierarchical phytosociology of the Greater Zandvlei area

Szöke, Tim 08 February 2017 (has links)
The Zandvlei Nature Reserve is to be expanded to form the Greater Zandvlei Estuary Nature Reserve and will encorporate a much greater area (250 more hectares). The Greater Zandvlei area was classified by means of Zurich Montpellier (Braun Blanquet) procedures. 60 relevés were used to create a hierarchical phytosociology using TWINSPAN and DCA-ordination analyses. 3 major community types were identified, which were then subdivided to reveal 6 community types important to future management: Moist Grassland/Wetland Disturbed Parkland, Dune Asteraceous Fynbos, Thicket/Shrub Mosaic, Rhus-Euclea Dune Thicket and Homogenous Patches. CCA-ordination indicates that the abiotic soil factors sampled (texture composition, pH, carbon content and visible disturbance) explain very little of the variation between the communities (r²=0.002). This phytosociology is provided as a tool for future research in the area, and it is hoped to assist in future management decisions regarding the newly founded GZENR.
174

Mercury Levels in Newly Independent Songbirds

Condon, Anne Moire 01 January 2008 (has links)
No description available.
175

The Effects of Environmental Variables on the Heart Rate of Invertebrates

DeFur, Peter L. 01 January 1977 (has links)
No description available.
176

Growth Response of Eelgrass (Zostera marina L) to Root-Rhizome and Whole Plant Exposure to Atrazine

Schwarzschild, Arthur C. 01 January 1993 (has links)
No description available.
177

Physical Parameters Affecting Incubating Temperatures in Loggerhead Sea Turtles, Caretta caretta, in Virginia

Jones, William Mason 01 January 1998 (has links)
Detailed physical profile of eight transplanted loggerhead sea turtle, Caretta caretta, nests were obtained from Virginia and northeastern North Carolina and reburied in Back Bay National Wildlife Refuge (BBNWR), Virginia Beach, Virginia during the summers of 1987, '88, and '89 to determine if the physical location of the egg within the nest had an affect on sex determination. Transplanted nests were reburied in sandy substrate at a depth of 15-60 em on south facing dunes, and a Campbell Scientific data-logger logged synchronously environmental data. The following data were collected: temperatures at various locations within a nest, net absorbed radiation, ambient temperature, rainfall (em), substrate moisture content, and tide cycles. To understand the determination of sex, a time series analyses was employed to explain the variability, the periodicity, and the irregular oscillations of the temperature data. The regression analysis, using the periodicity of the spring/neap cycles, indicated a significant diurnal and spring/neap tidal affect. The 29.5 and 14.7 day cycle were significant. In addition, a delayed heating affect on the dune temperatures was noted 3-5 days after the lowest tides of the full and new moon cycles which consistently occurred at approximately 3:00P.M. Temperature records in nests at BBNWR were consistent with those producing a predominance of male hatchlings (<28.0C). Temperatures which produced females did exist, but were infrequent. Maximum beach face heating resulted in elevating · temperatures from 1-3C at the 37cm depths. This affect could produce females in late summer and early fall. Physical parameters varied with depth, time of day, and season (summer/fall). The results of this study are important to conservation of sea turtles because they contribute much to the knowledge of how nest manipulation may control sex ratios. Using the approach developed in this study, a mathematical model to predict sex ratios could be developed that would be applicable for various physical regimes found on most major nesting beaches of various sea turtles around the world.
178

An Examination of Beta Diversity Indices and Their Predictors in Two Large-scale Systems

Schroeder, Philip 01 January 2018 (has links)
Biodiversity is what conservation biology was developed to conserve. It is the physical manifestation of life as a concept and, be it for practical or idealistic reasons, all conservationists seek to protect or, in some cases, enhance it. Because of its monolithic importance to the field, much effort has been expended trying to better measure and understand it. Recently, greater attention has been paid to the partition of diversity; the observation that the total diversity of a system (γ) can be broken down into within-site diversity (α) and between-site diversity (β). In particular, it has been noticed that the β component of diversity is not as well studied or understood as the α component. In this study I attempt to address this shortfall, by examining two questions: (1) how is β is best measured and (2) what drives β? To answer the first question, I look to find the measure of β that is most robust to sampling error. While many β indices have been proposed, few have considered how our methods of data gathering might affect those indices. Datasets collected from the real world will all likely have some sort of error within them as a result of the way they were sampled. Those errors will affect some indices more than others, and the indices that are least affected will be the most reliable for actual data. Once robust indices were identified, I used them to identify possible predictors of β in two large, national datasets. The first dataset was the National Lakes Assessment created by the USEPA, in which diatoms were sampled from over 1000 lakes across the country. The second was the eBird dataset from the Cornell Lab of Ornithology, which used citizen science to generate a continuous dataset spanning both the last decade and the boundaries of the conterminous United States. β calculated from these sources was regressed against relevant environmental variables to create a clearer understanding of the effects of the environment on the β of two very different ecological systems.
179

Biodiversity of Bariditae (Coleoptera: Curculionidae: Conoderinae) in Mississippi

Whitehouse, Ryan 01 May 2020 (has links)
A survey of Bariditae in Mississippi resulted in records of 75 species in 32 genera and included two undescribed species and 36 new state records. An additional two species were recognized as possibly occurring in Mississippi as well. Diagnoses for all of the genera and species in the state are provided and keys to the genera as well as all of the species were made. Species were found in every county within Mississippi and are representative of the Bariditae fauna of the southeastern United States. Open, prairie-like habitats and aquatic wetland habitats were the habitats with the highest biodiversity of Bariditae in the state. Species of Baris, Geraeus, Linogeraeus, and Odontocorynus, were found in the highest numbers and Linogeraeus and Sibariops were found to be the most speciose genera in the state. Sibariops amica, S. benigna, and S. houstoni, are proposed as new synonyms of S. concinna.
180

Isolation and Structure Elucidation of Antiproliferative Natural Products from Madagascar

Murphy, Brian Thacher 04 December 2007 (has links)
As part of an ongoing search for bioactive natural products from the endemic rainforests and surrounding ocean in Madagascar, a total of four extracts were comprehensively studied and were found to contain novel and/or bioactive compounds. The following dissertation discusses the isolation, structure elucidation, and bioactivity studies of these isolates. The following compounds from plants of Madagascar's rainforest are discussed in the order they were studied: flavonoids and long-chain compounds from Schizolaena hystrix, a cyclohexene derivative and butenolides from Artabotrys madagascariensis, and limonoids from Malleastrum sp. From the Malagasy marine ascidian Trididemnum sp. collected in the Indian Ocean, the identification as well as the potential biosynthetic origin of polyketide derived bistramides is reported. n an attempt to explore other facets of natural products chemistry, the second part of this dissertation discusses the process of designing potential anticancer agents based on the scaffold of a natural product. The biomolecular target of these studies is an enzyme that is overexpressed in tumor cells, namely Cdc25B, whose inhibition catalyzes cell cycle arrest at the G2/M transition of the cell cycle. Several analogs of a potent Cdc25B inhibitor were synthesized and tested in the enzyme-based assay. / Ph. D.

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