54 resultados para natural occurrence


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Pós-graduação em Agronomia (Horticultura) - FCA

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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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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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The occurrence of natural triploidy in two specimens of Astyanax scabripinnis collected in the Araqua river and in the Corrego das Pedras stream, respectively, is noticed. The triploid specimen from the Araqua river presented one macro B-chromosome and the triploid specimen from Corrego das Pedras stream presented two macro B-chromosomes. The C-banding performed in the specimen from the Araqua river confirmed the triploidy and showed that the macro B-chromosome was entirely heterochromatic. Ag-NOR characterization showed two chromosomes involved in the nucleolar activity in both specimens. Some aspects related to the origin of triploid fishes are described.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Ultraviolet (UV) filters are widely used in the formulation of personal care products (PCPs) to prevent damage to the skin, lips, and hair caused by excessive UV radiation. Therefore, large amounts of these substances are released daily into the aquatic environment through either recreational activities or the release of domestic sewage. The concern regarding the presence of such substances in the environment and the exposure of aquatic organisms is based on their potential for bioaccumulation and their potential as endocrine disruptors. Although there are several reports regarding the occurrence and fate of UV filters in the aquatic environment, these compounds are still overlooked in tropical areas. In this study, we investigated the occurrence of the organic UV filters benzophenone-3 (BP-3), ethylhexyl salicylate (ES), ethylhexyl methoxycinnamate (EHMC), and octocrylene (OC) in six water treatment plants in various cities in Southeast Brazil over a period of 6 months to 1 year. All of the UV filters studied were detected at some time during the sampling period; however, only EHMC and BP-3 were found in quantifiable concentrations, ranging from 55 to 101 and 18 to 115 ng L(-1), respectively. Seasonal variation of BP-3 was most clearly noticed in the water treatment plant in Araraquara, São Paulo, where sampling was performed for 12 months. BP-3 was not quantifiable in winter but was quantifiable in summer. The levels of BP-3 were in the same range in raw, treated and chlorinated water, indicating that the compound was not removed by the water treatment process.

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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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This work analyses the waveshapes of continuing currents and parameters of M-components in positive cloud-to-ground (CG) flashes through high-speed GPS synchronized videos. The dataset is composed of only long continuing currents (with duration longer than 40 ms) and was selected from more than 800 flashes recorded in Sao Jose dos Campos (45.864 degrees W, 23.215 degrees S) and Uruguaiana (29.806 degrees W, 57.005 degrees S) in Southeast and South of Brazil, respectively, during 2003 to 2007 summers. The videos are compared with data obtained by the Brazilian Lightning Location System (BrasilDAT) in order to determine the polarity of each flash and select only positive cases. There are only two studies of waveshapes of continuing currents in the literature. One is based on direct current measurements of triggered lightning, in which four different types of waveshapes were observed; and the other is based on measurements of luminosity variations in high-speed videos of CG negative lightning, in which besides the four types above mentioned two additional types were observed. The present work is an extension of the latter, using the same method but now applied to obtain the waveshapes of positive CG lightning. As far as the authors know, this is the first report on M-components in positive continuing currents. We also have used the luminosity-versus-time graphs to observe their occurrence and measure some parameters (duration, elapsed time and time between two successive M-components), whose statistics are presented and compared in detail to the data for negative flashes. We have plotted a histogram of the M-components elapsed time over the total duration of the continuing current for positive flashes, which presented an exponential decay (correlation coefficient: 0.83), similar to what has been observed for negative flashes. (C) 2008 Elsevier B.V. All rights reserved.

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The present study aimed to estimate the number of CD8(+) T and natural killer (NK) infiltrating cells and the expression of interleukin-10 (IL-10) and transforming growth factor beta 1 (TGF-beta1) in chemically induced neoplasms in an initiation-promotion bioassay for carcinogenesis. Male Wistar rats were treated with N-nitrosodiethylamine, N-methyl-N-nitrosourea, N-butyl-N-(4-hydroxybutyl) nitrosamine, dihydroxy-di-N-propylnitrosamine, and 1,2-dimethylhydrazine for 4 weeks. Two groups were subsequently exposed through diet to phenobarbital (0.05%) or 2-acetylaminofluorene (0.01%) for 25 weeks. An untreated group was used as a control. Immune cells and cytokines were immunohistochemically evaluated in neoplasms and in surrounding normal tissues at the liver, kidneys, lung, and small and large intestines. When compared to the respective normal tissues, an increased number of NK cells was verified infiltrating the colon, lung, and kidney neoplasms, while the number of CD8+ T cells decreased in the intestine and lung neoplasms. Expression of IL-10 was found mainly in kidney tumors. TGF-beta1 was expressed mainly in the liver and kidneys tumors. The results indicate that the differential occurrence of immune cells between neoplastic and normal tissues could be dependent upon tumor microenvironment.

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Neste trabalho, é relatada a infecção natural por Leishmania em um gato doméstico no qual, formas amastigotas do parasito foram observadas em imprint de linfonodo poplíteo. Reações sorológicas positivas e negativas foram observadas pelo teste de imunoadsorção enzimática (ELISA) e reação de imunofluorescência indireta (RIFI), respectivamente. A reação em cadeia da polimerase (PCR) revelou que a sequência de nucleotídeos foi idêntica à Leishmania (L.) chagasi. Este é o primeiro relato da doença em felino da cidade de Andradina, Estado de São Paulo, Brasil, área considerada endêmica para leishmaniose visceral canina e humana.

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Esta pesquisa avaliou o efeito da separação mãe-ninhada sobre o desempenho reprodutivo de coelhas lactantes e ponderal das ninhadas até aos 70 dias de idade. Examinaram-se 415 exposições ao macho de 157 fêmeas lactantes distribuídas em dois grupos: controle, com livre acesso ao ninho, e tratado, cujo acesso bloqueou-se entre o sétimo e o nono dias pós-parto, durante as 39 horas que precederam a cobrição. Das 415 exposições ao macho, 387 resultaram em cobrições e 264 em partos. As fêmeas tratadas, de quinta lactação em diante, apresentaram receptividade e taxa de parição, respectivamente, 6,7% e 10,8% maiores em comparação às fêmeas do grupo controle. Não se constatou efeito da interação tratamento x ordem de lactação, ou do tratamento, com respeito ao número de láparos/ninhada à desmama e nos 70 dias de idade. em ninhadas de primíparas, a taxa de mortalidade da separação até 70 dias de idade foi maior no grupo tratado, em relação ao controle (0,248±0,047 vs. 0,120±0,047). O peso total da ninhada à desmama foi inferior no grupo tratado, do que no controle (5.753±93 g vs. 6.222±89 g) em todas as ordens. Todavia, não se observou diferença no peso total ou médio da ninhada nos 70 dias de idade. O tratamento também reduziu o peso individual à desmama (912,4±4,9 g vs. 962,7±4,5 g) em todas as ordens de lactação, entretanto, elevou o ganho de peso médio diário pós-desmama (32,25±0,19 g/d vs. 31,44±0,17 g/d), proporcionando a ocorrência de ganho compensatório neste período. Pode-se recomendar a separação temporária mãe-ninhada para melhorar o desempenho reprodutivo de coelhas lactantes multíparas; mas deve ser evitada para as primíparas, devido à elevação da taxa de mortalidade das ninhadas.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)