Does water level affect benthic macro-invertebrates of a marginal lake in a tropical river-reservoir transition zone?

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Treatment efficiency of effluent prawn culture by wetland with floating aquatic macrophytes arranged in series

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Estudo de manobras evasivas com perturbações orbitais

Pós-graduação em Física - FEG

Análise da suscetibilidade a corridas de massa aplicada a dutovias: estudo de caso na bacia do Ribeirão do Roque

This scientific research aimed at to analyse the susceptibility to debris flow of the watershed of Ribeirão do Roque (SP), focusing on the upstream areas of OSBRA pipeline. This is because, mass flow can cause damage to pipes, mainly due to conditioning hydro erosion of the land in the drainage crossings, including the undermining the banks of streams. Firstly, It was conducted a literature review, aiming to identify and understand the principal characteristics and conditions of debris flow. Secondly, the physical and anthropic factors and their respective weights of influence were selected and used to determine the mass flow susceptibility. It was selected the following physical factors: type and thickness of rocks, soil and unconsolidated materials; textural density; amplitude relief; relief slope; shaped valley; and shape of slopes. Such factors are present in the physiographic subdivision map of the study area. In addition, the anthropic attributes correspond to the classes contained in the land use map. Therefore, the physical and anthropic factors were integrated through the multi-criteria analysis in a GIS environment, generating a total susceptibility map of debris flow on the scale 1:50,000. The results showed that a significative part of the study area was classified as average susceptibility. However, it was identified areas with high susceptibility in the region in which the pipe cross the Ribeirão do Roque. Moreover, at which point the river presents a closed valley and a meander shape, without a fluvial plain that would be useful to attenuate the development of the process. Consequently, if a mass flow begins in any of these most susceptible regions located upstream of the pipe, the chances that the process develops by the river and causes the excavations of his bed are quite large. However, the pipelines cross these critical areas directly on the rock (diabase), which provides additional protection against possible ...

Aprimoramento da sistemática U-Pb através do método de traços de fissão e técnicas de caracterização: termocronologia da faixa Brasília e sua correlação com a bacia do Paraná

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Influence of cage farming on feeding and reproductive aspects of Pimelodus maculatus Lacépède, 1803 (Siluriformes: Pimelodidae) in the Chavantes reservoir, Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

O conteúdo orgânico do sedimento influencia na distribuição intraespecífica de caranguejos-chama-maré

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Um predador generalista na fronteira entre ecossistemas: interações tróficas e os processos ecossitêmicos bromelícolas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Identification, Abundance and Rearing of Mysids of Gran Canaria: aplication to laboratory and oceanographic respiratory metabolism studies

Programa de doctorado en Oceanografía

Drusen do disco óptico e tilted disc

Trabalho Final do Curso de Mestrado Integrado em Medicina, Faculdade de Medicina, Universidade de Lisboa, 2014

Rugosidade de superfície de resinas compostas: diferentes procedimentos de polimento e acabamento

Dissertação para obtenção do grau de Mestre no Instituto Superior de Ciências da Saúde Egas Moniz

Causas e consequências da onivoria de peixes em ecossistemas aquáticos

Omnivory is a predominant feeding strategy among tropical fishes, but knowledge about its causes and consequences of this pattern is scarce. In this study we hypothesized that tropical fish feed lower in food web as a way to compensate a higher energetic demand, which increases with increasing water temperature and body size. Information about 8172 freshwater and marine fish species from whole world, from tropical and temperate ecosystems, showed that the trophic position of non-carnivore fish decreases with increasing body size in tropical but not in temperate ecosystems. This result indicates that the higher energetic demand of large-bodied tropical fish should exert a selective force in favor of omnivory. As a consequence, trophic dynamics in tropical freshwater ecosystems should have different patterns comparing to temperate ones, with major implications for water management and restoration of eutrophic aquatic ecosystems. Another hypothesis of this work was that effects of tropical omnivorous planktivorous fish on planktonic communities depend of primary producers stoichiometric composition, which depends of light availability relative to nutrients ratios. A mesocosm experiment, manipulating light availability and planktivorous fish presence, confirmed our hypothesis indicating that resource stoichiometric composition (consequently nutritional quality), determine trophic structure of pelagic food webs in tropical lakes. Finally another mesocosm experiment indicated that the removal of omnivorous benthivorous fish should be more efficient than removal of omnivorous planktivorus fish, as a way to improve water quality in tropical lakes and reservoirs. This last experiment showed that omnivorous planktivorous fish increase phytoplankton biomass due to trophic cascade interactions, without increasing nutrient concentrations in the water column. On the other hand, omnivorous benthivorous fish, feeding on detritus and other benthonic food sources and excreting nutrients in the water column, are responsible for translocate nutrient from sediments to the water column, increasing phosphorus pool and phytoplankton biomass. Thereby, internal phosphorus supply should be reduced and water quality of eutrophicated lakes could be improved by removing omnivorous benthivorous fish.

Causas e consequências da onivoria de peixes em ecossistemas aquáticos

Omnivory is a predominant feeding strategy among tropical fishes, but knowledge about its causes and consequences of this pattern is scarce. In this study we hypothesized that tropical fish feed lower in food web as a way to compensate a higher energetic demand, which increases with increasing water temperature and body size. Information about 8172 freshwater and marine fish species from whole world, from tropical and temperate ecosystems, showed that the trophic position of non-carnivore fish decreases with increasing body size in tropical but not in temperate ecosystems. This result indicates that the higher energetic demand of large-bodied tropical fish should exert a selective force in favor of omnivory. As a consequence, trophic dynamics in tropical freshwater ecosystems should have different patterns comparing to temperate ones, with major implications for water management and restoration of eutrophic aquatic ecosystems. Another hypothesis of this work was that effects of tropical omnivorous planktivorous fish on planktonic communities depend of primary producers stoichiometric composition, which depends of light availability relative to nutrients ratios. A mesocosm experiment, manipulating light availability and planktivorous fish presence, confirmed our hypothesis indicating that resource stoichiometric composition (consequently nutritional quality), determine trophic structure of pelagic food webs in tropical lakes. Finally another mesocosm experiment indicated that the removal of omnivorous benthivorous fish should be more efficient than removal of omnivorous planktivorus fish, as a way to improve water quality in tropical lakes and reservoirs. This last experiment showed that omnivorous planktivorous fish increase phytoplankton biomass due to trophic cascade interactions, without increasing nutrient concentrations in the water column. On the other hand, omnivorous benthivorous fish, feeding on detritus and other benthonic food sources and excreting nutrients in the water column, are responsible for translocate nutrient from sediments to the water column, increasing phosphorus pool and phytoplankton biomass. Thereby, internal phosphorus supply should be reduced and water quality of eutrophicated lakes could be improved by removing omnivorous benthivorous fish.

Busca por excesso no infravermelho médio em estrelas evoluídas com fotometria WISE e 2MASS

Debris discs are commonly detected orbiting main-sequence stars, but little is known regarding their fate as stars evolve along subgiant and giant stages. Jones (2008) has found strong evidence on the presence of mid-IR excess in G and K stars of luminosity class III, using photometric data from the Two-Micron All-Sky Survey (2MASS) and GLIMPSE catalogues. While the origin of these excesses remains uncertain, it is plausible that they arise from debris discs around these stars. The present study brings an unprecedent survey in the search for mid-IR excess among single and binary F, G and K-type evolved stars of luminosity classes IV, III, II and Ib. For this study, we use WISE and 2MASS photometric data for a sample of 3000 evolved stars, complete up to visual magnitude of 6.5. As major results, we found that the frequency of evolved stars showing mid-IR WISE excess increases from the luminosity classes IV and III to luminosity classes II and Ib. In addition, there is no clear difference between the presence of IR excess in binary and single stars for all the analyzed luminosity classes.

Busca por excesso no infravermelho médio em estrelas evoluídas com fotometria WISE e 2MASS

Debris discs are commonly detected orbiting main-sequence stars, but little is known regarding their fate as stars evolve along subgiant and giant stages. Jones (2008) has found strong evidence on the presence of mid-IR excess in G and K stars of luminosity class III, using photometric data from the Two-Micron All-Sky Survey (2MASS) and GLIMPSE catalogues. While the origin of these excesses remains uncertain, it is plausible that they arise from debris discs around these stars. The present study brings an unprecedent survey in the search for mid-IR excess among single and binary F, G and K-type evolved stars of luminosity classes IV, III, II and Ib. For this study, we use WISE and 2MASS photometric data for a sample of 3000 evolved stars, complete up to visual magnitude of 6.5. As major results, we found that the frequency of evolved stars showing mid-IR WISE excess increases from the luminosity classes IV and III to luminosity classes II and Ib. In addition, there is no clear difference between the presence of IR excess in binary and single stars for all the analyzed luminosity classes.