23,555 research outputs found

    Chaos and a Resonance Mechanism for Structure Formation in Inflationary Models

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    We exhibit a resonance mechanism of amplification of density perturbations in inflationary mo-dels, using a minimal set of ingredients (an effective cosmological constant, a scalar field minimally coupled to the gravitational field and matter), common to most models in the literature of inflation. This mechanism is based on the structure of homoclinic cylinders, emanating from an unstable periodic orbit in the neighborhood of a saddle-center critical point, present in the phase space of the model. The cylindrical structure induces oscillatory motions of the scales of the universe whenever the orbit visits the neighborhood of the saddle-center, before the universe enters a period of exponential expansion. The oscillations of the scale functions produce, by a resonance mechanism, the amplification of a selected wave number spectrum of density perturbations, and can explain the hierarchy of scales observed in the actual universe. The transversal crossings of the homoclinic cylinders induce chaos in the dynamics of the model, a fact intimately connected to the resonance mechanism occuring immediately before the exit to inflation.Comment: 4 pages. This essay received an Honorable Mention from the Gravity Research Foundation, 1998-Ed. To appear in Mod. Phys. Lett.

    Produção de suínos na fase de gestação em sistema de cama sobreposta.

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    bitstream/item/125843/1/Folder-Producao-Gestacao-cama-sobreposta-suinos.pdfFolder - PNMAI

    Uso de biodigestores para tratamento de resíduos animais.

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    bitstream/item/60189/1/CUsersPiazzonDocuments17238.pdfProjeto/Plano de Ação:

    As edifica√ß√Ķes e os detalhes construtivos voltados para o manejo de dejetos na suinocultura

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    bitstream/item/58213/1/doc113.pdfProjeto de controle da degradação ambiental decorrente da suinocultura em Santa Catarina

    Efeito de diferentes sistemas de aquecimento no desempenho de leitoes.

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    Modelo de edifica√ß√£o para a produ√ß√£o de leit√Ķes em cama sobreposta.

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    Edificação para produção de suínos em cama sobreposta na fase de creche.

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    bitstream/item/60164/1/CUsersPiazzonDocuments12852.pdfFolder. PNMA II: Projeto Suinocultura Santa Catarina. Convênio n.2002CV/000002
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