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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

Zhodnocení přírodní hodnoty a ekosystémových služeb přírodě blízkých biotopů v intenzivně využívané zemědělské krajině / Evaluation of the natural value and ecosystem services of natural biotops in the intensively managed agricultural landscape

HAVEL, Jaroslav January 2015 (has links)
My thesis is focused on valuation methods intensively used agricultural landscapes according to the importance of near-natural habitats in terms of their natural values and ecosystem services. This is done at four sites using pitfall traps, where there was a catch beetles (Carabidae). To evaluate the data I used indicators such as the Shannon index serenity. Procedures for calculating the ecological value of the area and the ecosystem services provided I processed according to the proposed method Seják et al., (2010). Rating I performed by BVM (,, habitat valuation methods "). Replacement cost method I used for the calculation of ecosystem services.
2

Contributions à la statistique bayésienne non-paramétrique / Contributions to Bayesian nonparametric statistic

Arbel, Julyan 24 September 2013 (has links)
La thèse est divisée en deux parties portant sur deux aspects relativement différents des approches bayésiennes non-paramétriques. Dans la première partie, nous nous intéressons aux propriétés fréquentistes (asymptotiques) de lois a posteriori pour des paramètres appartenant à l'ensemble des suites réelles de carré sommable. Dans la deuxième partie, nous nous intéressons à des approches non-paramétriques modélisant des données d'espèces et leur diversité en fonction de certaines variables explicatives, à partir de modèles qui utilisent des mesures de probabilité aléatoires. / This thesis is divided in two parts on rather different aspects of Bayesian statistics. In the first part, we deal with frequentist (asymptotic) properties of posterior distributions for parameters which belong to the space of real square sommable sequences. In the second part, we deal with nonparametric approaches modelling species data and the diversity of these data with respect to covariates. To that purpose, we use models based on random probability measures.
3

Efeitos do cultivo experimental de peixes em tanques-rede sobre a estrutura da comunidade fitoplanctônica em um braço do reservatório de Salto Caxias, região Sudoeste do Estado do Paraná / Effects of experimental fish farming in net cages on phytoplankton structure in an arm of Salto Caxias reservoir, Southeast of Paraná State

Bartozek, Elaine Cristina Rodrigues 11 June 2012 (has links)
Made available in DSpace on 2017-07-10T18:13:32Z (GMT). No. of bitstreams: 1 Elaine C Rodrigues Bartozek.pdf: 1985797 bytes, checksum: a358025d50258b7eaddead48b3a3dc40 (MD5) Previous issue date: 2012-06-11 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In Brazil, hydroelectric powerplant reservoirs are used for multiple purposes, among them, fish farming in net cages. The present study aimed to evaluate spacial and temporal variations of the abiotic variables, nutrients concentration, trophic state and composition and structure of the phytoplankton community in an arm of Salto Caxias reservoir influenced by experimental fish cultivation in net cages. Samples were bimontly betweem September 2010 and July 2011 at the subsurface of the pelagic zone in four sampling stations, been two of them placed in the arm influenced by the cultivation of 30 net cages and the other two in the cagaless arm. No significant differences were observed for composition, diversity, density and phytoplankton biomass between the treatments. The results of the analisys performed showed only seasonal variations, separating the dry from the rainy period. The values of species richness and Shannon diversity were low during the entire study period. Evenness was high in the dry period and low in the rainy period. Both arms were classified as oligotrophic, possible demonstrating low influence of the net cages in the environment. Phytoplankton density and biomass were higher during the rainy period. The dry period was represented mainly for Bacillariophyceae taxa and the rainy period by Cyanobacteria and Chlorophyceae. Two functional groups (FG) were observed (FG F and K), both of them typical from shallow environments with high transparency water. Variations in the phytoplakton structure seem to have been influenced mainly by the seazonality. The effects of the net cages in the nutrients concentration and phytoplankton structure were probably low, possibly due to the low number of net cages and fishes emploied and environment dinamics, influenced by the inflows of the upstream rivers. / No Brasil, reservatórios de usinas hidrelétricas são utilizados para múltiplas propostas, entre elas, o cultivo de peixes em tanques-rede. O presente estudo objetivou avaliar as variações espaciais e temporais das variávies abióticas, concentração de nutrientes, estado trófico e da composição e estrutura da comunidade fitoplanctônica em um braço do reservatório de Salto Caxias influenciado pelo cultivo experimental de peixes em tanques-rede. Foram realizadas amostragens bimestrais, entre setembro de 2010 e julho de 2011, à subsuperfície da zona pelágica, em quatro estações de amostragem, sendo duas localizadas em um braço influenciado pelo cultivo em 30 tanques-rede e duas em um braço não influenciado. Não foram registradas diferenças significativas para a composição, diversidade, densidade e biomassa fitoplanctônica entre os tratamentos utilizados. Os resultados das análises realizadas evidenciaram apenas variações sazonais, separando o período seco do período chuvoso. Os valores de riqueza de espécies e diversidade de Shannon foram baixos durante todo o período de estudo. A equitabilidade foi elevada no período seco e baixa no período chuvoso. Ambos os braços foram classificados como oligotróficos, demonstrando possivelmente baixa influência dos tanques-rede sobre o ambiente. A densidade e biomassa fitoplanctônica foram maiores durante o período chuvoso. O período seco foi representado principalmente por táxons de Bacillariophyceae e o período chuvoso por Cyanobacteria e Chlorophyceae. Dois grupos funcionais (GF) fitoplanctônicos foram observados (GF F e K), ambos característicos de ambientes rasos e com elevada transparência da água. As variações da estrutura fitoplanctônica parecem ter sido influenciadas principalmente pela sazonalidade. Os efeitos dos tanques-rede sobre a concentração de nutrientes e estrutura da comunidade fitoplanctônica parecem ter sido pouco significativos, possivelmente devido ao pequeno número de tanques-rede e peixes utilizados e a hidrodinâmica dos ambientes estudados, influenciados pelos influxos dos rios à montante.
4

The Effect of Dredging on Fish Communities in Agricultural Streams in Crawford, Sandusky and Seneca Counties of Ohio.

Selden, Justin D. 27 November 2013 (has links)
No description available.

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