11,242 research outputs found

    INPE LANDSAT system

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    Intensificação da bovinocultura de corte: estratégias de manejo reprodutivo e sanitário.

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    Manejo reprodutivo em gado de corte; Sincronizacao do estro em bovinos; Manejo sanitario em sistemas intensivos de producao de carne; Novos metodos de avaliacao da capacidade reprodutiva de touros.bitstream/CPPSE/12479/1/PROCIDoc26RTB636.0824LV.pd

    The Stellar Content of Obscured Galactic Giant HII Regions. VI: W51A

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    We present K-band spectra of newly born OB stars in the obscured Galactic giant H II region W51A and ~ 0.8'' angular resolution images in the J, H and K_S-bands. Four objects have been spectroscopically classified as O-type stars. The mean spectroscopic parallax of the four stars gives a distance of 2.0 \pm 0.3 kpc (error in the mean), significantly smaller than the radio recombination line kinematic value of 5.5 kpc or the values derived from maser propermotion observations (6--8 kpc). The number of Lyman continuum photons from the contribution of all massive stars (NLyc ~ 1.5 x 10^{50} s^{-1}) is in good agreement with that inferred from radio recombination lines (NLyc = 1.3 x 10^{50} s^{-1}) after accounting for the smaller distance derived here. We present analysis of archival high angular resolution images (NAOS CONICA at VLT and T-ReCS at Gemini) of the compact region W51 IRS2. The K_S--band images resolve the infrared source IRS~2 indicating that it is a very young compact HII region. Sources IRS2E was resolved into compact cluster (within 660 AU of projected distance) of 3 objects, but one of them is just bright extended emission. W51d1 and W51d2 were identified with compact clusters of 3 objects (maybe 4 in the case of W51d1) each one. Although IRS~2E is the brightest source in the K-band and at 12.6 \micron, it is not clearly associated with a radio continuum source. Our spectrum of IRS~2E shows, similar to previous work, strong emission in Brγ\gamma and HeI, as well as three forbidden emission lines of FeIII and emission lines of molecular hydrogen (H_2) marking it as a massive young stellar object.Comment: 31 pages and 9 figures, submitted to A

    Sistemas mistos de produção de leite e carne bovina.

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    Tanto do ponto de vista biológico quanto econômico, a pecuária bovina e uma atividade de produção conjunta porque produz, ao mesmo tempo. leite e carne (GOMES. 1993). O que varia é a ênfase ou a importância relativa dada a cada um dos produtos. 0 que proporciona a obtenção de varias classes de sistemas de produção. cujo número depende fundamentalmente do nível de especificidade desejado. Essa característica da pecuária bovina dificulta a conceituação exata dos sistemas mistos de produção de leite e carne, mas é importante no processo de tomada de decisões em todos os níveis deplanejamento (estratégico, tático, operacional). O objetivo deste artigo é apresentar, de forma resumida, o estado da arte sobre os sistemas mistos de produção de leite e carne bovina, considerando alguns aspectos importantes, com a conceituação a caracterização, a importância, as relações de natureza genética entre as produções de leite e de carne, os resultados experimentais e o potencial desses sistemas de produção no Brasil

    Properties of magnetic nanodots with perpendicular anisotropy

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    Nanodots with magnetic vortices have many potential applications, such as magnetic memories (VRAMs) and spin transfer nano-oscillators (STNOs). Adding a perpendicular anisotropy term to the magnetic energy of the nanodot it becomes possible to tune the vortex core properties. This can be obtained, e.g., in Co nanodots by varying the thickness of the Co layer in a Co/Pt stack. Here we discuss the spin configuration of circular and elliptical nanodots for different perpendicular anisotropies; we show for nanodisks that micromagnetic simulations and analytical results agree. Increasing the perpendicular anisotropy, the vortex core radii increase, the phase diagrams are modified and new configurations appear; the knowledge of these phase diagrams is relevant for the choice of optimum nanodot dimensions for applications. MFM measurements on Co/Pt multilayers confirm the trend of the vortex core diameters with varying Co layer thicknesses.Comment: 7 pages, 8 figure

    Early appraisal of the fixation probability in directed networks

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    In evolutionary dynamics, the probability that a mutation spreads through the whole population, having arisen in a single individual, is known as the fixation probability. In general, it is not possible to find the fixation probability analytically given the mutant's fitness and the topological constraints that govern the spread of the mutation, so one resorts to simulations instead. Depending on the topology in use, a great number of evolutionary steps may be needed in each of the simulation events, particularly in those that end with the population containing mutants only. We introduce two techniques to accelerate the determination of the fixation probability. The first one skips all evolutionary steps in which the number of mutants does not change and thereby reduces the number of steps per simulation event considerably. This technique is computationally advantageous for some of the so-called layered networks. The second technique, which is not restricted to layered networks, consists of aborting any simulation event in which the number of mutants has grown beyond a certain threshold value, and counting that event as having led to a total spread of the mutation. For large populations, and regardless of the network's topology, we demonstrate, both analytically and by means of simulations, that using a threshold of about 100 mutants leads to an estimate of the fixation probability that deviates in no significant way from that obtained from the full-fledged simulations. We have observed speedups of two orders of magnitude for layered networks with 10000 nodes
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