2,078 research outputs found

    Análise do espaço-temporal do uso da terra em microbacias hidrográficas no Município de Paragominas, Estado do Pará.

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    Paragominas located in the northeastern region of Pará, Brazil, constitutes one of the emblematic regions of deforestation process in Amazonia, this process occurred with the consolidation of the BR-010 Road, in the end of the 60's. In this paper, it is accessed the landscape dynamics in the watershed Cinqüenta e Quatro and Sete rivers, from the use of TM/Landsat of 2002, 2004 and 2005 images, analyzed by supervised classification by regions. It was verified that the class Anthropic Forest still has a prominent role among the mapped units, while the pasture areas represent the dominant patters of land use. For the landscape dynamics, the greatest percentuals of stability occurred for the class Anthropic Forest and Advanced Secondary Regrowth. Among the classes of land use, the pasture areas were more stable, although small conversions occurred for the class Grain Agriculture

    Nature of the constant factor in the relation between radial breathing mode frequency and tube diameter for single-wall carbon nanotubes

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    Resonance Raman scattering is used to determine the radial breathing mode (RBM) frequency (ωRBM) dependence on tube diameter (dt) for single-wall carbon nanotubes (SWNTs). We establish experimentally the ωRBM=227.0/dt as the fundamental relation for pristine SWNTs. All the other RBM values found in the literature can be explained by an upshift in frequency due mostly to van der Waals interaction between SWNTs and environment

    Changes in hematological and biochemical parameters of tambaqui (Colossoma macropomum) parasitized by metazoan species.

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    The aim of this study was to evaluate the impacts of metazoan parasites on hematological and biochemical parameters and relative condition factor of tambaqui (Colossoma macropomum) farmed in northern Brazil. A total of 32 juvenile fish were captured from a commercial fish farm located in the municipality of Rio Preto da Eva, Amazonas state, Brazil. Parasite prevalence was 100% for Anacanthorus spathulatus, Mymarothecium boegeri and Notozothecium janauachensis, 100% for Neoechinorhynchus buttnerae and 53.13% for Dolops geayi. The greatest mean parasite intensity was found in acantocephalans followed by monogeneans and branchiuran crustaceans. A negative correlation was observed between abundance of N. buttnerae and hematocrit percentage, hemoglobin concentration, total thrombocyte count and glucose and between abundance of the monogenean and glucose concentration. Parasitic infections caused damage in tambaqui in terms of the observed hematological parameters that were characterized by hypochromic anemia and thrombocytopenia, which are important parameters to be used in parasitic diagnosis. This study is the first record of the occurrence of Dolops geayi in farmed tambaqui in the Amazon
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