1000 resultados para Elementos traça


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The Curimataú estuary is located in the oriental coast of Rio Grande do Norte State in Brazil. Its importance resides in the fact that this region possesses one of the last portions of preserved mangrove in the Rio Grande do Norte State. Nevertheless, it has been severely affected by many anthropogenic activities, as sugarcane monoculture and shrimp farming. Former works demonstrated that an accumulation of heavy metals is occurring in oysters in this estuary, and perhaps it could be explained by the input of metals in this ecosystem deriving from the shrimp farming. To better understanding the origin of these metals, bottom sediment samples, cores and suspended particulate matter were collected for a characterization of metal concentrations (Al, Ba, Cd, Cu, Cr, Fe, Mn, Ni, Pb, Zn) and to determine the potentially bioavailable metals. Additionally, the enrichment ratio for each element analyzed was calculated. The mineralogical composition of sediment samples and cores were obtained by X-ray diffraction. Moreover, data of orbital remote sensing were used in order to detect and quantify suspended matter by applying a logarithmic algorithm. Geochemical data of bottom sediments and cores revealed that, excepting Ba and Pb, the elements analyzed presented concentrations characteristic of an unpolluted ecosystem (Al: 0,25 - 8,76 %; Ba: 3,03 - 870 µg.g-1; Cd: < 0,25 µg.g-1; Cr: 1,72 - 82,4 µg.g-1; Cu: 0,12 -25,3 µg.g-1; Pb: 0,38 - 23,7 µg.g-1; Fe: 0,10 - 5,82 %; Mn: 15,1 - 815 µg.g-1; Ni: 0,14 - 36,1 µg.g-1; Zn: 1,37 - 113 µg.g-1). During the dry season a distribution pattern was observed, with higher metal concentrations in the margins, decreasing toward the central portion of the channel. These metal concentrations were well correlated with mineralogical compositions, with clay minerals prevailing at the margins, and quartz and feldspar in the center. However, this pattern was not observed during the wet season, probably because of the high water flux that disturbed bottom sediments. But, as observed for the dry season, a good correlation between metal concentrations and mineralogical composition was also observed for the wet season, with high metal concentrations where there were high quantities of clay minerals. Low enrichment ratios were obtained for the majority of elements analyzed, excepting for Mn, Ba and Pb. Manganese presented the higher ratios downstream for both seasons, and it can be an evidence of anthropogenic impact by shrimp farming. As barium and lead concentrations in sediment samples presented analytical problems during the total sample digestion, one cannot be sure that the ratios obtained correspond to the reality. The highest metal concentrations in particulate matter were obtained in the portion dominated by fluvial transport for all metals analyzed, excepting for copper. Barium and zinc were the only elements that presented elevated concentrations that are not common of unpolluted ecosystems (Ba: 5730 - 8355 µg.g-1; Zn: 3899 - 4348 µg.g-1). However, these high concentrations could not be related to the shrimp farming and waste waters from the town of Canguaretama, once they were obtained from the fluvial particulate matter, that is upstream from the activities above mentioned. The application of the logarithmic algorithm to the processed LANDSAT image was well succeeded, although the acquired image does not correspond exactly to the field campaigns. The IKONOS image provided very detailed views of the suspended sediment concentration at the estuary, as the mixture of distinct water flows at the confluence of Cunhaú and Curimataú rivers, with more turbid waters from Cunhaú river, that is directly affected by effluents from shrimp farming and urban waste waters deriving from the town of Canguaretama

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The study area is inserted in Ponta do Tubarão region, Macau City, setentrional littoral of Rio Grande do Norte State, composed of Tertiary and Quatemary sedimentary rocks and sediments. This region is characterized for the intense action of the coastal processes, causing the morphologic instability in part of the area, beyond the interference of human activities, as the Petroliferous Industrial Polo, salt companies and shrimp farms. This justifies the integration of multidisciplinary and multitemporal detailed scientific studies dealing with the evaluation of the changing behavior of this coastal environment by geoenvironments elements characterization, identifying protected and recuperation areas, mainly those under socioeconomic intervention. The main objective was the coastal monitoring using geoprocessing techniques to prepare thematic maps useful for oil spilling environment risk areas survey. The methodology was based on multitemporal interpretation of remote sensing images and field checking, integrated in a Geographical Information System (GIS). The Geologic, Geomorphologic, Vegetation, Soil and Land Use maps were prepared, and later on they allowed the generation of the Natural Vulnerability and Environmental Vulnerability maps. These maps had been classified in accordance with vulnerability degrees: very low, low, medi um, high and very high. Beyond these maps the GIS allowed the analysis of the shoreline evolution for 10 distinct dates, using Landsat 5 TM and 7 ETM+ and SPOT-HRVIR images. This analysis made possible the attendance of the coastal morphodynamic evolution, where the results had been represented by areasof erosion and accretion (or deposition) of sediments, pointing critical areas under erosive process to the petroliferous industry (Macau and Serra fields). The GIS also provided to prepare the Environmental Sensitivity Maps of Oil Spill (SAO Maps) in operational scale (1: 10.000), according to the norms ofthe Ministério do Meio Ambiente (MMA 2002). The SAO Map in operational scale was based on IKONOS images mosaic where the ESI (Environmental Sensitivity Index) was represented according with two tides phases of theregion. Therewere recognizedfiveESI (3, 4,7,9, 1O) for the low tide; to the high tide the ESI number increased to seven (3, 4, 5, 7, 8, 9, 10). All these information are necessary to the decisions making about oi! spill and its derivatives containment. These techniques application makes possible the optimization and implantation ofnew socioeconomics activities of low environmental impact, indicates areas for better productivity and security exploration, and benefits local communities with fauna and flora preservation. The development of these activities is inserted in the scope of Monitoramento Ambiental de Áreas de Risco a Derrames de Petróleo e Seus Derivados Cooperation Project (Rede 05/01 - PETRORISCO, FINEP/CTPETRO/PETROBRAS) of multidisciplinary and interinstitucional characteristics dealing with subjects involving the environmental monitoring and the petroliferous activity

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This study aims at analysing the (re) prodction of urban space in the south sone of Natal city, in particular the influence of the shopping-centers in this process. In this respect, it also analyses the changes of habits and constumes for part of the society, when those entreprizes were built in better-off areas of the south zone Natal as well as the transformations in the surroundings of the thre main shopping-centers. A sother commercial establishments of the same size, two out of the three main shopping-centers in the city are targered towards the better-off population. However, if compared to the others, one these has, for some time, sought to target a lower in come population. In spite of being an important element in the (re)production of urban space as well as in the cities modern commercial sector, these large commercial entreprizes reinforce capitalisms contradctions in so far as they constitute semi-public space whit an exclusionary and segregatory vatune

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

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Foram examinados os hemócitos de larvas do 2º (L2) e 3º(L3) instares de Dermatobia hominis em nível de microscopia óptica e comparados com os de outras espécies encontradas na literatura. Nas L2 e em L3 com peso de até 200mg foram encontrados cinco tipos: Pro-hemócitos, Plasmatócitos, Vermiformes, Oenocitóides e Esfoliativas. A medida em que as L3 foram-se tornando mais idosas apareceram em seqüência os Granulócitos e Adipohemócitos, sendo raro encontrar-se Pro-hemócitos em L3 com peso acima de 500mg. Tipos intermediários entre Pro-hemócitos e Plasmatócitos e entre Granulócitos e Adipohemócitos também foram encontrados, fazendo-se supor que pro-hemócitos dão origem ao Plasmatócito e que este dá origem ao Granulócito que pode acumular grãos de lipídeos transformando-se em Adipohemócito. O Oenocitóide parece ter origem diferente dos demais tipos. Não foram encontradas formas transicionais entre Plasmatócito fusiforme e Vermiforme típica conforme aparece na literatura para algumas espécies. Embora sem ter característica de hemócitos, as células Esfoliativas são elementos que aparecem nos dois instares estudados.

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O objetivo desta pesquisa foi caracterizar os elementos físicos da bacia do córrego Santo Antônio, buscando compreender a influência que a área de entorno dessa bacia exerce sobre a Floresta Estadual Edmundo Navarro de Andrade (FEENA). Para isto, foram elaboradas as cartas geomorfológica e de uso do solo, além da compilação de dados geológicos, pedológicos e climáticos. Essa influência foi avaliada em termos da dinâmica de remobilização de materiais provenientes das nascentes, que não pertencem a FEENA, e que se constituem, portanto, em área de uso agrícola. A análise das características físicas indicou que essa área é susceptível a ação dos processos morfogenéticos e que estes foram intensificados e acelerados pelo uso do solo ao redor das nascentes. Verifica-se, assim, a necessidade de se reavaliar esse uso e de se fiscalizar o cumprimento da própria legislação ambiental, no que se refere ao uso e ocupação do território, em fundos de vale.

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Este artigo apresenta uma reflexão a respeito de algumas concepções teóricas de autoridade e hierarquia, e de como essas concepções se constituem em elementos da cultura escolar que é construída na interação cotidiana, definindo formas diferenciadas de participação nas escolas. Parte do pressuposto de que a escola, como organização burocrática, tem em sua estrutura um corpo de princípios e valores dados pelo sistema educacional, por meio de leis, decretos e papéis formalmente estabelecidos, e um outro corpo de princípios e valores construídos e reelaborados no seu interior, pelos participantes do processo educacional, formando a cultura escolar. Assim, o grau de participação nas escolas se definiria em razão das concepções que seriam compartilhadas e construídas nesse processo de constituição da cultura escolar.

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

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

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

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Teve-se o objetivo de desenvolver um modelo matemático por meio de análise de elementos finitos, utilizando o programa computacional ANSYS®, versão 5.7, para otimizar o projeto de máquina recolhedora de frutos de café no terreiro. A modelagem da máquina foi realizada com base no levantamento das características aerodinâmicas dos frutos de café e da vazão de ar necessária para o transporte pneumático dos frutos. Foram obtidas, experimentalmente, as pressões estáticas nos dutos da máquina, sendo esses valores comparados com os resultados determinados pelo programa ANSYS, no intuito de validar o modelo. Com base nos resultados numéricos obtidos, concluiu-se que a modelagem desenvolvida apresentou resultados próximos aos determinados experimentalmente, obtendo erro relativo médio nos valores simulados de pressão de 9,2%. Por meio da modelagem, identificaram-se faixas de pressão que dificultariam o transporte pneumático dos frutos de café em alguns pontos da máquina. Esses problemas foram corrigidos e, com isso, o fluxo de ar proporcionado pelo ventilador foi suficiente para succionar os frutos de café no terreiro e transportá-los para dentro do reservatório da máquina. A modelagem desenvolvida atendeu às necessidades propostas no trabalho para o recolhimento dos frutos de café utilizando transporte pneumático eficientemente.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The feeding nonpreference of Plutella xylostella (L.) larvae was tested in regard to the cauliflower genotypes Barcelona, Verona, Piracicaba Precoce, Sharon, Silver Streak (hybrids) and Teresopolis Gigante (cultivar). Choice and no-choice tests were carried out at the laboratories of the Departamento de Fitossanidade, FCAV/UNESP, Jaboticabal, state of São Paulo, Brazil, to study attractiveness and dry mass consumption by 1st-instar (just hatched) and 4th-instar larvae for 24 hours. No significant difference was found for attractiveness in choice and no-choice tests, for both 1st-and 4th-instar larvae. The consumption of dry mass in both tests, with 1st-and 4th-instar larvae, showed a significant difference between genotypes only for 1st-instar larvae, the hybrid Silver Streak being the most consumed (3.72 mg) by P. xylostella larvae. The cauliflower genotypes tested presented no variation in attractiveness for 1st-instar (just hatched) and 4th-instar larvae and did not present nonpreference feeding resistance for P. xylostella larvae.

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This work intends to analyze the application and execution time of a numerical algorithm that simulates incompressible and isothermal flows. It was used the explicit scheme of the Characteristic Based Split (CBS) algorithm and the Artificial Compressibility (AC) scheme for coupling pressure-velocity equations. The discretization was done with the finite element method using a bilinear elements grid. The free software GNU-Octave was used for implementation and execution of routines. The results were analyzed using the classic lid-driven cavity problem. This work shows results for tests with several Reynolds' number. The results for these tests show a good agreement when compared with previous ones obtained from bibliography. The code runtime's analysis shows yet that the matrix's assembly is the part of greater consumption time in the implementation.