1,994 research outputs found

    Sistemas de produção de leite utilizando pastagens.

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    Em decorrência das profundas mudanças no cenário econômico de nosso Pais ocorridas nos últimos anos, a demanda por informações técnicas referentes a producao de leite aumentou significativamente. Este novo contexto, em que palavras como globalização, competitividade, eficiência, qualidade e produtividade estão na ordem do dia, exige do produtor uma atitude no sentido mudar a situação de sua propriedade, sob pena de não ser competitivo e em curto período de tempo, abandonar a atividade. E nesta hora, no entanto, que muitos desastres acontece, pois a maioria resolve investir, sem qualquer planejamento ou assessoria técnica, os poucos e últimos recursos em fatores considerados não produtivos, que pouco ou nada contribuirão para as mudanças que se fazem necessarias

    Opções de recursos volumosos para época seca.

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    Silagem de milho; Silagem de sorgo; Silagem de gramineas tropicais (elefante, tanzania, etc); Cana-de-acucar; Fenos

    Physics of collisionless shocks - theory and simulation

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    Collisionless shocks occur in various fields of physics. In the context of space and astrophysics they have been investigated for many decades. However, a thorough understanding of shock formation and particle acceleration is still missing. Collisionless shocks can be distinguished into electromagnetic and electrostatic shocks. Electromagnetic shocks are of importance mainly in astrophysical environments and they are mediated by the Weibel or filamentation instability. In such shocks, charged particles gain energy by diffusive shock acceleration. Electrostatic shocks are characterized by a strong electrostatic field, which leads to electron trapping. Ions are accelerated by reflection from the electrostatic potential. Shock formation and particle acceleration will be discussed in theory and simulations

    The effects of solar incidence angle over digital processing of LANDSAT data

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    A technique to extract the topography modulation component from digital data is described. The enhancement process is based on the fact that the pixel contains two types of information: (1) reflectance variation due to the target; (2) reflectance variation due to the topography. In order to enhance the signal variation due to topography, the technique recommends the extraction from original LANDSAT data of the component resulting from target reflectance. Considering that the role of topographic modulation over the pixel information will vary with solar incidence angle, the results of this technique of digital processing will differ from one season to another, mainly in highly dissected topography. In this context, the effects of solar incidence angle over the topographic modulation technique were evaluated. Two sets of MSS/LANDSAT data, with solar elevation angles varying from 22 to 41 deg were selected to implement the digital processing at the Image-100 System. A secondary watershed (Rio Bocaina) draining into Rio Paraiba do Sul (Sao Paulo State) was selected as a test site. The results showed that the technique used was more appropriate to MSS data acquired under higher Sun elevation angles. Topographic modulation components applied to low Sun elevation angles lessens rather than enhances topography

    A water level relationship between consecutive gauge stations along Solim\~oes/Amazonas main channel: a wavelet approach

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    Gauge stations are distributed along the Solim\~oes/Amazonas main channel to monitor water level changes over time. Those measurements help quantify both the water movement and its variability from one gauge station to the next downstream. The objective of this study is to detect changes in the water level relationship between consecutive gauge stations along the Solim\~oes/Amazonas main channel, since 1980. To carry out the analyses, data spanning from 1980 to 2010 from three consecutive gauges (Tefe, Manaus and Obidos) were used to compute standardized daily anomalies. In particular for infra-annual periods it was possible to detect changes for the water level variability along the Solim\~oes/Amazonas main channel, by applying the Morlet Wavelet Transformation (WT) and Wavelet Cross Coherence (WCC) methods. It was possible to quantify the waves amplitude for the WT infra-annual scaled-period and were quite similar to the three gauge stations denoting that the water level variability are related to the same hydrological forcing functions. Changes in the WCC was detected for the Manaus-Obidos river stretch and this characteristic might be associated with land cover changes in the floodplains. The next steps of this research, will be to test this hypotheses by integrating land cover changes into the floodplain with hydrological modelling simulations throughout the time-series

    Topographic studies through texture image analysis of LANDSAT data

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    There are no author-identified significant results in this report

    Use of LANDSAT data to monitor pasture project in Amazonia

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    The author has identified the following significant results. No differences were found between acreage evaluation by visual and automatic interpretation of LANDSAT images. It was necessary to interpret both channels 5 and 7 to exactly outline the deforested areas. Channel 7 was necessary for the identification of deforested areas in the presence of recently grown natural vegetation, and channel 5 was necessary to identify the deforested areas in the cerrado regions. Automatic interpretation permitted the discrimination between areas with predominant grass coverage and recently grown natural vegetation

    Tuned liquid dampers simulation for earthquake response control of buildings

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    This paper is focused on the study of an earthquake protection system, the Tuned Liquid Damper (TLD), which can, if adequately designed, reduce earthquake demands on buildings. This positive effect is accomplished taking into account the oscillation of the free surface of a fluid inside a tank (sloshing). The behaviour of an isolated Tuned Liquid Damper, subjected to a sinusoidal excitation at its base, with different displacement amplitudes, was studied by finite element analysis. The efficiency of the TLD in improving the seismic response of an existing building, representative of modern architecture buildings in southern European countries was also evaluated based on linear dynamic analyses

    Alternativas inovadoras para otimizar a transferência de tecnologia para a agricultura familiar.

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    Editado por Flávio Augusto Portela Santos, José Carlos de Moura, Vidal Pedroso de Faria
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