5,489 research outputs found

    O aleitamento interrompido como prática para antecipar o aparecimento do estro em porcas.

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    bitstream/item/59090/1/CUsersPiazzonDocuments105.pd

    Low field hysteresis in disordered ferromagnets

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    We analyze low field hysteresis close to the demagnetized state in disordered ferromagnets using the zero temperature random-field Ising model. We solve the demagnetization process exactly in one dimension and derive the Rayleigh law of hysteresis. The initial susceptibility a and the hysteretic coefficient b display a peak as a function of the disorder width. This behavior is confirmed by numerical simulations d=2,3 showing that in limit of weak disorder demagnetization is not possible and the Rayleigh law is not defined. These results are in agreement with experimental observations on nanocrystalline magnetic materials.Comment: Extended version, 18 pages, 5 figures, to appear in Phys. Rev.

    Cosmological Imprint of an Energy Component with General Equation of State

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    We examine the possibility that a significant component of the energy density of the universe has an equation-of-state different from that of matter, radiation or cosmological constant (Λ\Lambda). An example is a cosmic scalar field evolving in a potential, but our treatment is more general. Including this component alters cosmic evolution in a way that fits current observations well. Unlike Λ\Lambda, it evolves dynamically and develops fluctuations, leaving a distinctive imprint on the microwave background anisotropy and mass power spectrum.Comment: revised version, with added references, to appear in Phys. Rev. Lett. (4 pages Latex, 2 postscript figures

    Influência dos meios de cultura sólido e líquido no alongamento de brotos in vitro de abacaxi ornamental (Ananas lucidus Miller).

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    Influencia dos meios de cultura solido e liquido no alongamento de brotoss in vitro de abacaxi ornamental.bitstream/CNPAT-2010/5395/1/Pa-057.pd
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