2,181 research outputs found

    Wave Equations for Classical Two-Component Proca Fields in Curved Spacetimes with Torsionless Affinities

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    The world formulation of the full theory of classical Proca fields in generally relativistic spacetimes is concisely reviewed and the entire set of pertinent field equations is transcribed in a straightforward way into the framework of one of the Infeld-van der Waerden formalisms. Some well-known calculational techniques are then utilized for deriving the wave equations that control the propagation of the fields allowed for. It appears that no interaction couplings between such fields and electromagnetic curvatures are carried by the wave equations at issue. What results is, in effect, that the only interactions which ultimately occur in the theoretical context under consideration involve strictly Proca fields and wave functions for gravitons.Comment: Many improvements on the paper have still been made. In particular, its title has been modified so as to conform further to one of its main aim

    Agricultura sem fogo na Amazônia Oriental: formiga como indicador agroecológico.

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    Edição dos Anais do XVIII Simpósio de Mirmecologia, São Paulo, 2007

    Controle de doenças do maracujazeiro através do uso de produtos alternativos.

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    Publicado também em: Fitopatologia Brasileira, v. 30, p. S59, ago. 2005. Suplemento. Resumos do XXXVIII Congresso Brasileiro de Fitopatologia

    Constatação de Curvularia eragrostides em mudas de dendÛ no Estado do Pará.

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    Resumos do XXXVIII Congresso Brasileiro de Fitopatologia. Resumo 207. Título: dendÚ [i.e. dendê]

    Development of peach flower buds under low winter chilling conditions

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    Here, we reviewed both endogenous and exogenous factors involved in the processes of flower bud formation and flower development in peach, analyzing how they can be affected by climatic change in temperate zones, explored the expansion of peach to tropical or subtropical zones. The process of flower bud formation in peach differs between low winter chilling and temperate conditions. Although the main steps of flower development are maintained, the timing in which each one occurs is different, and some processes can be altered under low winter chilling conditions, with a great impact on fruit production and crop management. Further studies on flower bud induction and differentiation under warmer conditions are fundamental for addressing the alterations in flower bud development that negatively impact on next season’s harvest. In the future, horticulturalists and scientists will face several challenges, mainly how high temperatures affect the expression of the main genes regulating flower formation and how to improve crop management in these conditions
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