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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.
1

Parametric, Non-Parametric And Statistical Modeling Of Stony Coral Reef Data

Hoare, Armando 08 April 2008 (has links)
Like coral reefs worldwide, the Florida Reef Tract has dramatically declined within the past two decades. Monitoring of 40 sites throughout the Florida Keys National Marine Sanctuary has undertaken a multiple-parameter approach to assess spatial and temporal changes in the status of the ecosystem. The objectives of the present study consist of the following: In chapter one, we review past coral reef studies; emphasis is placed on recent studies on the stony corals of reefs in the lower Florida Keys. We also review the economic impact of coral reefs on the state of Florida. In chapter two, we identify the underlying probability distribution function of the stony coral cover proportions and we obtain better estimates of the statistical properties of stony coral cover proportions. Furthermore, we improve present procedures in constructing confidence intervals of the true median and mean for the underlying probability distribution. In chapter three, we investigate the applicability of the normal probability distribution assumption made on the pseudovalues obtained from the jackknife procedure for the Shannon-Wiener diversity index used in previous studies. We investigate a new and more effective approach to estimating the Shannon-Wiener and Simpson's diversity index. In chapter four, we develop the best possible estimate of the probability distribution function of the jackknifing pseudovalues, obtained from the jackknife procedure for the Shannon-Wiener diversity index used in previous studies, using the xi nonparametric kernel density estimate method. This nonparametric procedure gives very effective estimates of the statistical measures for the jackknifing pseudovalues. Lastly, the present study develops a predictive statistical model for stony coral cover. In addition to identifying the attributable variables that influence the stony coral cover data of the lower Florida Keys, we investigate the possible interactions present. The final form of the developed statistical model gives good estimates of the stony coral cover given some information of the attributable variables. Our nonparametric and parametric approach to analyzing coral reef data provides a sound basis for developing efficient ecosystem models that estimate future trends in coral reef diversity. This will give the scientists and managers another tool to help monitor and maintain a healthy ecosystem.
2

Dubysos upės vidurupio vandens kokybės vertinimas bioindikacijos metodais / Middle of the river Dubysa water quality assessment by the methods of bioindication

Keblaitė, Živilė 20 June 2012 (has links)
Šio darbo tikslas – įvertinti Dubysos upės vidurupio vandens kokybę, taikant bioindikacinius vandens telkinių vertinimo metodus. Naudojant Saprobiškumo (S) ir Simpsono įvairovės indeksų (D) metodus buvo identifikuoti zooplanktoniniai organizmai bei įvertinti rūšių skaičiaus, gausumo ir įvairovės pasiskirstymo dėsningumai. Pagal J. Brown-Blanquet skalę atliktas atskirų augalų rūšių gausumo (projekcinis padengimo) barelyje vertinamas. Apie 50 km atkarpoje buvo išdėstytos 15 tyrimų vietų, kurias pasirenkant buvo atsižvelgiama į netoliese esančius žemės ūkio, pramonės, transporto objektus bei gamtinę aplinką. Tiriant zooplanktoniną paimti 270 vandens ir vandens – dumblo mėginiai. Šie tyrimai atlikti tris kartus metuose, bandymą pakartojant tris kartus. Naudojant J. Brown-Blanquet skalę augalų projekcinio padengimo vertinimas atliktas liepos mėn. Taigi vandens kokybės vertinimui buvo skaičiuoti tokie rodikliai: zooplanktoninių organizmų rūšių skaičius, gausumas, Simpsono įvairovės (D), Saprobiškumo (S) indeksai bei augalų projekcinis padengimas. Tirtoje teritorijoje buvo aptikta 33 zooplanktono rūšys: 8 infuzorijos, 8 dumbliai, 2 bakterijos, 2 vabzdžių lervos, 3 verpetės, 4 pirmuonys, 2 šakotaūsiai ir 3 irklakojai vėžiagyviai. Taikyta vienfaktorinė dispersinė analizė (One–way ANOVA) parodė, kad tyrimų vietos vandens kokybė (vandens užterštumas arba švarumas) turi įtakos vandens kokybę indikuojantiems rodikliams (rūšių skaičiui, gausumui, D bei S indeksams). Rūšių sudėtis ir... [toliau žr. visą tekstą] / The aim – to assess middle of the river Dubysa water quality, using valuation techniques by bioindicationous water mines. Using saprobic index (S) and Simpson's diversity index (D) methods have been identified zooplanktons organisms and the number of species, abundance and diversity of distribution patterns. According to J. Brown-Blanquet scale of an individual plant species richness (covering projection) rating in the barrel. About 50 km stretch was down 15 test sites, the choice was taken to the nearby agricultural, industrial, transport facilities and the environment. Studying zooplankton, it was taken of 270 water mines, and water - sludge ("hanging drop") samples. These studies were conducted three times a year, repeating the test three times. Using J. Brown-Blanquet scale projection covering the plant assessment was carried out in July. Thus, the assessment of water quality indicators have been calculated as follows: organisms zooplankton number of species, abundance, Simpson's diversity index (D), saprobic index (S) and the projection coating plant. There was found 33 species of investigated zooplankton area: 8 infusoria, 8 algae, 2 bacteria, 2 insect larvae, 3 vortex, 4 protozoa, crustaceans 2 and 3 copepods. Applied to one factor analysis of variance (one-way ANOVA) revealed that research on local water quality (water pollution or purity) affect water quality for indication indicators (number of species, abundance, D index). Species composition and quantitative... [to full text]
3

Retail District Evolution: An Exploration of Retail Structure and Diversity, a Case Study in Denton, Texas

Bova, Joshua Paul 08 1900 (has links)
It is well established that national retail chains impact small, single location retail businesses in terms of revenue generation, retail structure, retail type diversity, and location. This study examines the retail structure and diversity of five retail districts in the City of Denton, Texas. The analysis focuses on one central business district (CBD), one traditional retail strip center (University Drive, also known as US HWY 380), one special retail district (Fry Street District), one traditional enclosed shopping mall and associated development (Golden Triangle Mall), and one power retail center (Denton Crossing). The empirical foundation for the investigation is a historical business database covering years 1997 to 2010, obtained from Info Group's Reference USA. This Reference USA database includes location, industry, and status (single versus chain location) information for each business. Retail diversity and evenness were measured for each of the five retail districts using the Simpson's Diversity Index and the Simpsons Measure of Evenness, leading to specification of the differences that exist in retail structure and diversity among the districts. Golden Triangle Mall and Denton Crossing were primarily chain location in composition while Fry Street District, the CBD, and University Drive were primarily single location in composition. Across all years, the single versus chain status of the local business communities did not substantially change within any of the districts. The Fry Street District exhibited the most change in diversity as well as the lowest overall diversity among the retail districts, followed by University Drive and Golden Triangle Mall. The CBD did not experience any major change in retail type diversity. However, all retail districts experienced major changes in retail evenness. Overall for the city, single location retail businesses accounted for the majority of all the retail businesses, however, chain locations employed more people. In total, these findings indicate that the development of retail districts composed primarily of chain location retailer's affects retail district diversity and evenness but not retail structure.

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