626 research outputs found

    ANÁLISE INTEGRADA DA VARIAÇÃO ESPACIAL DO TRANSPORTE DE SEDIMENTOS NO RIO SANTO ANASTÁCIO, OESTE PAULISTA

    Get PDF
    Este trabalho tem como objetivos a avaliação dos padrões de transporte de sedimentos no canal do rio Santo Anastácio no Oeste Paulista, através de amostragem direta no campo e mapeamento temático. Os resultados apontam para relacionamento direto dos sedimentos com o fluxo do rio nas seções a montante, e inverso nas seções a jusante. As influências do meio físico foram mais eficientes sobre os materiais em suspensão

    CARACTERIZAÇÃO DA DRENAGEM FLUVIAL E A VARIABILIDADE ESPAÇO-TEMPORAL DA VAZÃO ESPECÍFICA MÉDIA NAS BACIAS HIDROGRÁFICAS DOS RIOS AGUAPEÍ E PEIXE, NO OESTE DO ESTADO DE SÃO PAULO

    Get PDF
    As bacias hidrográficas dos rios Aguapeí e Peixe estão localizadas na porção Oeste do estado de São Paulo e por possuírem características geográficas semelhantes especialmente em termos climáticos, foi realizado um estudo da vazão específica média, juntamente com a caracterização da drenagem fluvial. Análise esta que demonstra a influência direta do sistema de drenagem na vazão específica, até mesmo quando levado em consideração a variabilidade temporal

    FATORES GEOMORFOLÓGICOS DETERMINANTES DO PROCESSO DE AVULSÃO: O VALE ALUVIAL DO RIO DO PEIXE, SP.

    Get PDF
    O estudo avaliou a geomorfologia do rio do Peixe, SP, e identificou aspectos que contribuíram para a formação e extensão de um processo de avulsão. Informações cartográficas, levantamentos em campo e dados hidrológicos foram usados nesta análise. Os resultados mostraram o maior processo de avulsão dos últimos 50 anos no rio do Peixe que alterou a rede de drenagem criando o único trecho multicanal. Os dados indicam a largura da planície e a reocupação de paleocanais como propulsores da avulsão

    Treatment of geophysical data as a non-stationary process

    Full text link

    Outer Regions of the Milky Way

    Full text link
    With the start of the Gaia era, the time has come to address the major challenge of deriving the star formation history and evolution of the disk of our MilkyWay. Here we review our present knowledge of the outer regions of the Milky Way disk population. Its stellar content, its structure and its dynamical and chemical evolution are summarized, focussing on our lack of understanding both from an observational and a theoretical viewpoint. We describe the unprecedented data that Gaia and the upcoming ground-based spectroscopic surveys will provide in the next decade. More in detail, we quantify the expect accuracy in position, velocity and astrophysical parameters of some of the key tracers of the stellar populations in the outer Galactic disk. Some insights on the future capability of these surveys to answer crucial and fundamental issues are discussed, such as the mechanisms driving the spiral arms and the warp formation. Our Galaxy, theMilkyWay, is our cosmological laboratory for understanding the process of formation and evolution of disk galaxies. What we learn in the next decades will be naturally transferred to the extragalactic domain.Comment: 22 pages, 10 figures, Invited review, Book chapter in "Outskirts of Galaxies", Eds. J. H. Knapen, J. C. Lee and A. Gil de Paz, Astrophysics and Space Science Library, Springer, in pres

    Radiating black hole solutions in arbitrary dimensions

    Full text link
    We prove a theorem that characterizes a large family of non-static solutions to Einstein equations in NN-dimensional space-time, representing, in general, spherically symmetric Type II fluid. It is shown that the best known Vaidya-based (radiating) black hole solutions to Einstein equations, in both four dimensions (4D) and higher dimensions (HD), are particular cases from this family. The spherically symmetric static black hole solutions for Type I fluid can also be retrieved. A brief discussion on the energy conditions, singularities and horizons is provided.Comment: RevTeX 9 pages, no figure

    VALORES ENERGÉTICOS DO MILHO E DO FARELO DE SOJA DETERMINADOS COM POEDEIRAS NA FASE DE PRODUÇÃO

    Get PDF
    The aim of the present research work, carried out with laying hens in the stage of production, was the determination of both apparent metabolic energy (AME) and the nitrogen corrected apparent metabolic energy (AMEn) of the corn and soybean meals. A total of 84 Isabrown birds aging 24 weaks were alloted in a randomized blocks design, using two basal reference diets containing 19 and 14% of CP, respectively. For the experiment, two samples of corn replaced in 25% the reference diet containing 19% of CP, and three samples of soy bean meal replaced in 15% the reference ration containing 14% of CP. It hás been found significant differences in regard to the energetic values and the metabolic coefficients of the reference diets added with soybean meal. In conclusion, it hás been found that the EMA and EMAn values, expressed as kcal/kg as dry matter, for the three samples of soybean meal were 2,292 and 2,537; 2,248 and 1,963; 3,252 and 2,847, respectively, and for the samples of corn, 3,157 and 3,061 and 3,477, respectively.O presente trabalho teve pôr objetivo a determinação, em poedeiras em fase de produção, dos valores de energia metabolizável aparente (EMA) e da (EMAn) corrigida pelo balanço de nitrogênio, do milho e do farelo de soja. Foram utilizadas 84 aves Isabrown com 24 semanas de idade, distribuídas em delineamento experimental de blocos ao acaso, utilizando-se duas rações-referência com 19 e a4% de PB (Proteína Bruta), respectivamente. No experimento levado a efeito, duas amostras de milho substituíram em 25% a ração com 19% de PB e três amostras de farelo de soja substituíram em 15% a ração com 14%  de PB, tendo sido verificada diferença significativa nos valores energéticos e nos coeficientes de metabolizabilidade das  e de amostras de farelo de soja estudadas. Em conclusão, verificou-se que os valores de EMA e EMAn para as três amostras de farelo de soja foram de 2.992, 2.537; 2.248 e de 3.157 e 3.061; e 3.590 e 3.477 kcal/kg de matéria seca, respectivamente, e de 3.157 e 3.061; e 3.590 e 3.477 kcal/kg de matéria seca para as duas amostras de milho, respectivamente

    A widespread family of phage-inducible chromosomal islands only steals bacteriophage tails to spread in nature

    Get PDF
    Phage satellites are genetic elements that couple their life cycle to that of helper phages they parasitize, interfering with phage packaging through the production of small capsids, where only satellites are packaged. So far, in all analyzed systems, the satellite-sized capsids are composed of phage proteins. Here, we report that a family of phage-inducible chromosomal islands (PICIs), a type of satellites, encodes all the proteins required for both the production of small-sized capsids and the exclusive packaging of the PICIs into these capsids. Therefore, this new family, named capsid-forming PICIs (cf-PICIs), only requires phage tails to generate PICI particles. Remarkably, the representative cf-PICIs are produced with no cost from their helper phages, suggesting that the relationship between these elements is not parasitic. Finally, our phylogenomic studies indicate that cf-PICIs are present both in gram-positive and gram-negative bacteria and have evolved at least three times independently to spread in nature

    Gravitational collapse of a Hagedorn fluid in Vaidya geometry

    Get PDF
    The gravitational collapse of a high-density null charged matter fluid, satisfying the Hagedorn equation of state, is considered in the framework of the Vaidya geometry. The general solution of the gravitational field equations can be obtained in an exact parametric form. The conditions for the formation of a naked singularity, as a result of the collapse of the compact object, are also investigated. For an appropriate choice of the arbitrary integration functions the null radial outgoing geodesic, originating from the shell focussing central singularity, admits one or more positive roots. Hence a collapsing Hagedorn fluid could end either as a black hole, or as a naked singularity. A possible astrophysical application of the model, to describe the energy source of gamma-ray bursts, is also considered.Comment: 14 pages, 2 figures, to appear in Phys. Rev.
    corecore