987 resultados para 13077-059


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Using the U(4) formalism developed ten years ago, the worldsheet action for the superstring in Ramond-Ramond plane wave backgrounds is expressed in a manifestly N = (2,2) superconformally invariant manner. This simplifies the construction of consistent Ramond-Ramond plane wave backgrounds and eliminates the problems associated with light-cone interaction point operators. © SISSA/ISAS 2002.

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The aim of this study was to estimate the effect of the association between carrot and lettuce crops in several intercropping systems through different yield advantage indexes, as well as to assess which system is better for the environmental resources management with respect to productivity and economic indicators. A 'group balanced block' experimental design was used, with four replications. Cultivars of lettuce crispleaf ('Lucy Brown', 'Tainá', 'Laurel' and 'Verônica') and looseleaf ('Babá de Verão', 'Maravilha das Quatro Estações', 'Elisa' and 'Carolina') groups were evaluated in intercropping systems with 'Alvorada' and 'Brasilia' carrot cultivars. The land equivalent ratio (LER) and yield efficiency index (YEI) were estimated, besides economic indicators such as gross (GI) and net (NI) income, modified monetary advantage (MMA), return rate (RR) and profit margin (PM). The evaluated indexes showed that carrot is the dominant and lettuce the dominated crop. Higher biological/agronomic efficiency indexes and economic indicators were observed in intercropping systems with 'Brasilia' carrot as component crop and that based on the crispleaf lettuce group.

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the aim of this study was to validate the Alternate Current Biosusceptometry (ACB) for monitoring gastric contractions in rats. In vitro data were obtained to establish the relationship between ACB and the strain-gauge (SG) signal amplitude. In vivo experiments were performed on rats with magnetic markers and SGs previously implanted under the gastric serosa. The effects of the prandial state in gastric motility profiles were obtained. The correlation between in vitro signal amplitudes was strong (R = 0.989). The temporal cross-correlation between the ACB and SG signal amplitude was higher in the postprandial than in the fasting state. Irregular signal profiles, low contraction amplitudes, and smaller signal-to-noise ratios explained the poor correlation for fasting-state recordings. The contraction frequencies using ACB were 0.068 ± 0.007 Hz (postprandial) and 0.058 ± 0.007 Hz (fasting) and those using SG were 0.066 ± 0.006 Hz (postprandial) and 0.059 ± 0.008 Hz (fasting) (P < 0.003). When a magnetic tracer was ingested, there was a strong correlation and a small phasedifference between techniques. We conclude that ACB provides an accurate and sensitive technique for studies of GI motility in the rat. © 2010 IEEE.

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Residues generated from wood processing and transformation result in a considerable waste of raw material, which adds no value to such noble good. The purpose of this study was to determine the yield of sawn timber from Itaúba (Mezilaurus itauba) and Tauarí (Couratari guianensis) species. To this end, the volumetry and yield percentage of three logs from each species were classified and calculated. The Tauarí species resulted in yields for logs 1, 2 and 3, of 49.70% to 50.28% 39.20%, respectively; while for the Itaúba species, the yields for logs 1, 2 and 3 were of 51.03%; 50.29%; and 47.60%, respectively. It was not possible to verify whether the classification of log quality have influenced the yield.

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High systolic blood pressure caused by endothelial dysfunction is a comorbidity of metabolic syndrome that is mediated by local inflammatory signals. Insulin-induced vasorelaxation due to endothelial nitric oxide synthase (eNOS) activation is highly dependent on the activation of the upstream insulin-stimulated serine/threonine kinase (AKT) and is severely impaired in obese, hypertensive rodents and humans. Neutralisation of circulating tumor necrosis factor-α (TNFα) with infliximab improves glucose homeostasis, but the consequences of this pharmacological strategy on systolic blood pressure and eNOS activation are unknown. To address this issue, we assessed the temporal changes in the systolic pressure of spontaneously hypertensive rats (SHR) treated with infliximab. We also assessed the activation of critical proteins that mediate insulin activity and TNFα-mediated insulin resistance in the aorta and cardiac left ventricle. Our data demonstrate that infliximab prevents the upregulation of both systolic pressure and left ventricle hypertrophy in SHR. These effects paralleled an increase in AKT/eNOS phosphorylation and a reduction in the phosphorylation of inhibitor of nuclear factor-κB (Iκβ) and c-Jun N-terminal kinase (JNK) in the aorta. Overall, our study revealed the cardiovascular benefits of infliximab in SHR. In addition, the present findings further suggested that the reduction of systolic pressure and left ventricle hypertrophy by infliximab are secondary effects to the reduction of endothelial inflammation and the recovery of AKT/eNOS pathway activation. © 2012 Elsevier B.V.

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We evaluated messenger RNA (mRNA) expression of the growth-hormone (GHR) and insulin-like growth factor (IGF-1) genes in 28-day-old Japanese meat quails fed diets containing 0, 8, or 12% dietary glycerol in substitution of corn. Total RNA was extracted from the breast muscle and the DNA was amplified with specific primers using real-time PCR. Feed conversion ratio and feed intake were evaluated. The birds fed 8 and 12% glycerol presented higher IGF-1 mRNA expression [0.059 and 0.049 arbitrary units (AU), respectively] relative to those not fed with glycerol (0.029 AU), while 12% glycerol reduced GHR mRNA expression (0.022 AU). Dietary inclusion of 8% glycerol promoted similar performance results (feed conversion) as the diet with no glycerol. We conclude that inclusion of glycerol in the diet affects GHR and IGF-1 gene expression in Japanese meat quails. However, considering the performance results and the expression of the GHR and IGF-1 genes, 8% glycerol may be safely included in the diet of meat quails. © FUNPEC-RP.

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We modify the ansatz for embedding chameleon scalars in string theory proposed in [1] by considering a racetrack superpotential with two KKLT-type exponentials e ia instead of one. This satisfies all experimental constraints, while also allowing for the chameleon to be light enough on cosmological scales to be phenomenologically interesting. © 2013 SISSA, Trieste, Italy.

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

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Nos lagos de várzea da Amazônia a oscilação do nível da água e as variações sazonal e diária nos parâmetros determinam a estrutura da comunidade íctica. Este trabalho teve como objetivo caracterizar a estrutura das comunidades de peixes em quatro lagos de várzea da Reserva de Desenvolvimento Sustentável Mamirauá (Médio Solimões), no estado do Amazonas, em diferentes fases do ciclo sazonal. O estudo foi desenvolvido durante um ano, com coletas bimestrais em quatro lagos da RDSM. Foram analisadas a riqueza de espécies e biomassa dos peixes, e investigados em que medidas os padrões das comunidades foram regulados pelas variáveis ambientais. Foi coletado um total de 6.059 indivíduos, distribuídos em 117 espécies, 76gêneros, 21 famílias e seis ordens. As ordens Characiformes e Siluriformes foram as que apresentaram maior número de famílias e espécies, juntas representando cerca de 90% dos indivíduos capturados. A composição da ictiofauna variou entre os períodos de coleta e entre os lagos, sendo os maiores valores de riqueza e biomassa encontrados no período da vazante, com exceção do lago Taracoá que apresentou maior riqueza na enchente. As espécies Potamorhina latior, Potamorhina altamazonica, Mylossoma duriventre, Amblydoras hancokii, Amblydoras sp., Liposarcus pardalis, Psectrogaster amazonica e Osteoglossum bicirrhosum dominaram a amostragem em número de indivíduos coletados, enquanto que Oxydoras niger, Colossoma macropomum, Cichla monoculus, Osteoglossum bicirrhosum, Arapaima gigas e Pseudoplatystoma tigrinum a dominam em termos de sua biomassa. A análise dos parâmetros físico-químicos mostra que a variação ao longo do ano e do pulso de alagamento, determinam a estrutura das comunidades ícticas nos lagos, sendo que o efeito conjunto do oxigênio dissolvido, pH e temperatura da água parece explicar melhor o padrão de composição da ictiofauna. A análise de similaridade mostra que, no mesmo período do ciclo hidrológico em anos consecutivos, a composição da ictiofauna se assemelha. Logo, é provável que a composição da comunidade íctica se restabeleça a cada ciclo, com o estabelecimento da conexão dos corpos d’água durante a cheia.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)