552 research outputs found

    Manejo agroecológico de pastagens: experiências da fazendinha agro-ecológica km 47.

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    O objetivo deste trabalho foi avaliar o manejo agroecológico de pastagens consorciadas no pastejo de vacas leiteiras em sistema orgânico de produção. Foram avaliadas a disponibilidade de matéria seca (MS) e a composição química da pastagem pela produção de biomassa e teores de proteína bruta (PB), fibra em detergente neutro (FDN) e ácido (FDA), lignina, celulose e hemicelulose respectivamente. As experiencias foi realizado durante o período de 2006 à 2008 no Sistema Integrado de Produção Agroecológica (SIPA), convênio Embrapa/UFRRJ, localizado no município de Seropédica, Rio de Janeiro. O manejo agroecológico do consórcio com leguminosas constitui importante alternativa para se melhorar a qualidade nutricional da forragem em sistema orgânico de produção

    Topology and Fragility in Cosmology

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    We introduce the notion of topological fragility and briefly discuss some examples from the literature. An important example of this type of fragility is the way globally anisotropic Bianchi V generalisations of the FLRW k=−1k=-1 model result in a radical restriction on the allowed topology of spatial sections, thereby excluding compact cosmological models with negatively curved three-sections with anisotropy. An outcome of this is to exclude chaotic mixing in such models, which may be relevant, given the many recent attempts at employing compact FLRW k=−1k=-1 models to produce chaotic mixing in the cosmic microwave background radiation, if the Universe turns out to be globally anisotropic.Comment: 12 pages, LaTex file, to appear in Gen. Rel. Grav. (1998

    Informes da avaliação de genótipos de girassol 2006/2007 e 2007.

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    Características gerais da Rede Oficial de Avaliação de Genótipos de Girassol; Resultados dos ensaios finais de primeiro e de segundo ano - safra 2006/2007 e safrinha 2007; Lista dos genótipos de girassol avaliados e registrados no Ministério da Agricultura, Pecuária e Abastecimento - MAPA.bitstream/item/80263/1/Informes-da-avaliacao-de-genotipos-de-girassol-2006-2007-e-2007.pd

    Topology Change in Canonical Quantum Cosmology

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    We develop the canonical quantization of a midisuperspace model which contains, as a subspace, a minisuperspace constituted of a Friedman-Lema\^{\i}tre-Robertson-Walker Universe filled with homogeneous scalar and dust fields, where the sign of the intrinsic curvature of the spacelike hypersurfaces of homogeneity is not specified, allowing the study of topology change in these hypersurfaces. We solve the Wheeler-DeWitt equation of the midisuperspace model restricted to this minisuperspace subspace in the semi-classical approximation. Adopting the conditional probability interpretation, we find that some of the solutions present change of topology of the homogeneous hypersurfaces. However, this result depends crucially on the interpretation we adopt: using the usual probabilistic interpretation, we find selection rules which forbid some of these topology changes.Comment: 23 pages, LaTex file. We added in the conclusion some comments about path integral formalism and corrected litle misprinting

    Homogeneity, Flatness and "Large" Extra Dimensions

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    We consider a model in which the universe is the direct product of a (3+1)-dimensional Friedmann, Robertson-Walker (FRW) space and a compact hyperbolic manifold (CHM). Standard Model fields are confined to a point in the CHM (i.e. to a brane). In such a space, the decay of massive Kaluza-Klein modes leads to the injection of any initial bulk entropy into the observable (FRW) universe. Both Kolmogoro-Sinai mixing due to the non-integrability of flows on CHMs and the large statistical averaging inherent in the collapse of the initial entropy onto the brane smooth out any initial inhomogeneities in the distribution of matter and of 3-curvature on any slice of constant 3-position. If, as we assume, the initial densities and curvatures in each fundamental correlation volume are drawn from some universal underlying distributions independent of location within the space, then these smoothing mechanisms effectively reduce the density and curvature inhomogeneities projected onto the FRW. This smoothing is sufficient to account for the current homogeneity and flatness of the universe. The fundamental scale of physics can be \gsim 1TeV. All relevant mass and length scales can have natural values in fundamental units. All large dimensionless numbers, such as the entropy of the universe, are understood as consequences of the topology of spacetime which is not explained. No model for the origin of structure is proffered.Comment: minor changes, matches version published in Phys. Rev. Let

    Attachment styles and personal growth following romantic breakups: The mediating roles of distress, rumination, and tendency to rebound

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    © 2013 Marshall et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.This article has been made available through the Brunel Open Access Publishing Fund.The purpose of this research was to examine the associations of attachment anxiety and avoidance with personal growth following relationship dissolution, and to test breakup distress, rumination, and tendency to rebound with new partners as mediators of these associations. Study 1 (N = 411) and Study 2 (N = 465) measured attachment style, breakup distress, and personal growth; Study 2 additionally measured ruminative reflection, brooding, and proclivity to rebound with new partners. Structural equation modelling revealed in both studies that anxiety was indirectly associated with greater personal growth through heightened breakup distress, whereas avoidance was indirectly associated with lower personal growth through inhibited breakup distress. Study 2 further showed that the positive association of breakup distress with personal growth was accounted for by enhanced reflection and brooding, and that anxious individuals’ greater personal growth was also explained by their proclivity to rebound. These findings suggest that anxious individuals’ hyperactivated breakup distress may act as a catalyst for personal growth by promoting the cognitive processing of breakup-related thoughts and emotions, whereas avoidant individuals’ deactivated distress may inhibit personal growth by suppressing this cognitive work
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