Interacting spin 0 fields with torsion via Duffin-Kemmer-Petiau theory

Here we study the behaviour of spin 0 sector of the DKP field in spaces with torsion. First we show that in a Riemann-Cartan manifold the DKP field presents an interaction with torsion when minimal coupling is performed, contrary to the behaviour of the KG field, a result that breaks the usual equivalence between the DKP and the KG fields. Next we analyse the case of Teleparallel Equivalent of General Relativity Weitzenbock manifold, showing that in this case there is a perfect agreement between KG and DKP fields. The origins of both results are also discussed.Comment: 10 pages, no figures, uses REVTEX. Changes in the presentation, minor misprints and one equation corrected. References updated. To appear in General Relativity and Gravitatio

Conformal invariance of massless Duffin-Kemmer-Petiau theory in Riemannian space-times

We investigate the conformal invariance of massless Duffin-Kemmer-Petiau theory coupled to riemannian space-times. We show that, as usual, in the minimal coupling procedure only the spin 1 sector of the theory -which corresponds to the electromagnetic field- is conformally invariant. We show also that the conformal invariance of the spin 0 sector can be naturally achieved by introducing a compensating term in the lagrangian. Such a procedure -besides not modifying the spin 1 sector- leads to the well-known conformal coupling between the scalar curvature and the massless Klein-Gordon-Fock field. Going beyond the riemannian spacetimes, we briefly discuss the effects of a nonvanishing torsion in the scalar case.Comment: 8 pages, no figures. Major changes in contend and results. To appear in Class.Quant.Gra

Sistema de produção de tambaqui em tanques-rede.

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Cultivo de tambaqui sob gaiolas flutuantes.

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Criação de tambaqui Colossoma macropomum em gaiolas flutuantes no município de São Sebastião da Boa Vista, ilha do Marajó, Estado do Pará.

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A variabilidade genética do feijoeiro (Phaseolus vulgaris L.): aplicações nos estudos das interações simbióticas e patogênicas.

A variabilidade genética da hospedeira. Como esta variabilidade pode ser manipulada? A simbiose com o rizóbio. Melhoramento genético do feijoeiro visando a fixação biológica de nitrogênio. As interações e sua utilização no melhoramento da planta.bitstream/CNPAB-2010/27393/1/doc126.pd