833 resultados para Datação de sedimento eólico


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O presente estudo teve como objetivos principais analisar a biodiversidade de macroinvertebrados bentônicos em diferentes pontos localizados no fundo da Lagoa do Mian, zona de desembocadura do rio Paranapanema, na Represa de Jurumirim, Estado de São Paulo. Nove pontos de amostragem ao longo da lagoa foram selecionados, distribuídos em três transectos. Cada transecto possuía um ponto na margem direita, um ponto na margem esquerda e um ponto no meio. As coletas foram realizadas em dois períodos do ano, um em março e outro em agosto, para fins de comparação. 2009 representou um ano atípico com relação aos níveis pluviométricos, ocorrendo chuvas intensas no período de julho (um mês tipicamente seco). Foram medidas as variáveis físico-químicas da água, tais como: transparência, profundidade, oxigênio dissolvido, pH, condutividade elétrica e temperatura. Foram recolhidas amostras do sedimento para análise da fauna bentônica e análise do sedimento (quantidade de matéria orgânica presente e granulometria) utilizando-se a draga de Petersen. O material foi triado sob microscópio estereoscópico. A seguir, foi feita a identificação e contagem dos indivíduos. Medidas de densidade, abundância relativa, riqueza, diversidade e equitabilidade foram calculadas. A análise mostrou maior abundância dos táxons no mês de agosto, apontando para a predominância de alguns grupos, como Chaoboridae, Nematoda, Oligochaeta e Chironomidae, este último apenas no segundo mês de coleta. A distribuição dos organismos foi mais significativamente influenciada pela a condutividade elétrica da água, pela transparência, pelo oxigênio dissolvido e por características do sedimento

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Studies regarding the quality and quantity of water have become more and more important because of the increasing negative environmental impacts occurred and their scarcity increase as well. At the Center of Tropical Fish Research (Centro de Pesquisas de Peixes Tropicais - CEPTAlIBAMA) located in the city of Pirassununga, SP, there is a dam named Represa Velha which supplies 128 tanks that are fish hatcheries. This dam takes in part of the Barrinha stream micro-basin where it has been observed strong impacts due to the deforestation of its support forest, as well an the intensive agricultural activities in the neighboring areas. There has been established and distributed 13 points of water-collectors disposed inside the stream and the dam. The water samples were taken from the stream only from its surface because of the low depth and, inside. In the dam, the water samples were taken at the water column, at a 50cm distance over the sediment. In every point of collection inside the dam, it was placed a chamber of sedimentation, vertically in the water column at a 70% height from the total depth. The collections took place during the dry/cold and raining/warm periods of the years 2000 and 2001. Then, it were analyzed the physical, physical-chemical, chemical and micro-biological parameters of the water samples. The obtained results were statistically analyzed throughout the SAS system (Statistical Analisys System). Parameters such as total phosphate, nitrate, nitrite and turbidity were within the established limits for the Class 2 water, according to the n° 20/1986 CONAMA Resolução. However, the total and Escherichia coli coliforms, mainly inside the Barrinha stream, had showed values above of the established limits for the same... (Complete abstract click electronic access below)

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Introduces technical, economic and environmentally competitive solutions in the energy market is a great challenge for society. This work examines each of these aspects considering the production of electrolytic hydrogen with energy from wind power, solar and hydropower, in order to ensure an overview of this energy carrier. Initially, an assessment of the technical aspects is made addressing existing electrolysers technologies, its main characteristics and differences. The geographical distribution of wind, solar and hydroelectric potential in Brazil is also mapped, and a configuration scheme of a hydrogen production system is discussed. Subsequently, the economic analysis calculates the cost of investment in the alkaline electrolyser of 60 Nm³ / h, similar to the Brazilian bus powered by hydrogen project, coordinated by EMTU. Since the main input of electrolysis is electricity, is analyzed the latest energy auctions of each primary source and it is calculated the cost of production of the wind, solar and hydropower hydrogen. Postponed to this, are investigated the intrinsic environmental impacts of electricity generation process, proposing a readjustment of an indicator of ecological efficiency for the production of hydrogen. Finally, the work discusses the concept of externalities and demonstrates how the incorporation of external costs can leverage the hydrogen economy. In short, it is evident that the wind and hydroelectric hydrogens are more promising compared to solar hydrogen, whether in the economic aspect, because it achieved lower costs, whether in the environmental aspect, because it reached the highest ecological efficiency

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

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The renewable energy sources presents an important role on the world's current context, its growing is essentially connected to the environmental issues and the energetic security, guided by the search for alternatives of energy. Among the alternative energy sources, the wind energy shows great importance in the brazilian territory, it has a great potential still unexplored and constant growth in the national electric matrix. The specific factor of generation, the conjuncture and the incentive politics influence on the expansion of wind energy in Brazil. Thus, the brazilian wind sector shows features which can be evaluated enable its developing. Keeping that in mind, the present work aims identify which are the advantages and the difficulties for the expansion of this energy source in the brazilian electric matrix. For that, the work studies the different parameters: features of electric generation of the different energy sources, incentive politics, generation costs, CO2 emission, evolution of wind energy in Brazil, the brazilian wind potential, and the regime of complementarily hydro-wind

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Pós-graduação em Geociências e Meio Ambiente - IGCE

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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We investigated the influence of environmental factors in spatial and temporal distribution of the seabob shrimp Xiphopenaeus kroyeri in Santos Bay and São Vicente Estuary, state of São Paulo, Brazil. Monthly samples were obtained, from May 2008 through April 2010, from four locations in the estuary and four in the bay. No individual was collected in the estuary and this was attributed to the low salinity means recorded in this environment. We collected 109,153 individuals in the bay and there was no difference in abundance between the two years comprised by the study period. The similarity in spatial distribution can be related to sediment grain size that in all sampling locations showed great amount of very fine sand. The largest amount of reproductive females was obtained in early 2010, when temperature was high, and this could have increased the juvenile recruitment in April 2010. According to our results, the distribution of X. kroyeri in the study area is influenced by temperature, which is related to reproduction, and salinity, limiting the entrance of individuals in the estuarine region.

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Diel variation in the abundance and size of Pleoticus muelleri in the Ubatuba region was investigated during 2000. During each season of the year, sampling was conducted during the day and at night at 8 depths, from 5 to 40 m. The estimated number of shrimp was 955 individuals, 272 collected during the day and 683 at night. There was a difference in the abundance of P. muelleri between day and night (χ², p=2.33E-40). The abundance during the day and at night differed by season with the exception of the spring (χ², p=0.06). The abundance during both periods also differed by depth, except at 15 and 30 m, where it was not significant (χ², p=0.84 and 0.06, respectively). The shrimp caught at night were generally smaller than those caught during the day (Kolmogorov-Smirnov, p<0.01). Pleoticus muelleri juveniles were found primarily at night. This tendency could have influenced the lower mean size for this period. The sediment type and the bottom temperature appear to influence the behavior of this species and consequently the catch rate during the periods analyzed.