Renormalization of the N=1 Abelian Super-Chern-Simons Theory Coupled to Parity-Preserving Matter

We analyse the renormalizability of an Abelian N=1 super-Chern-Simons model coupled to parity-preserving matter on the light of the regularization independent algebraic method. The model shows to be stable under radiative corrections and to be gauge anomaly free.Comment: Latex, 7 pages, no figure

Tunable asymmetric magnetoimpedance effect in ferromagnetic NiFe/Cu/Co films

We investigate the magnetization dynamics through the magnetoimpedance effect in ferromagnetic NiFe/Cu/Co films. We observe that the magnetoimpedance response is dependent on the thickness of the non-magnetic Cu spacer material, a fact associated to the kind of the magnetic interaction between the ferromagnetic layers. Thus, we present an experimental study on asymmetric magnetoimpedance in ferromagnetic films with biphase magnetic behavior and explore the possibility of tuning the linear region of the magnetoimpedance curves around zero magnetic field by varying the thickness of the non-magnetic spacer material, and probe current frequency. We discuss the experimental magnetoimpedance results in terms of the different mechanisms governing the magnetization dynamics at distinct frequency ranges, quasi-static magnetic properties, thickness of the non-magnetic spacer material, and the kind of the magnetic interaction between the ferromagnetic layers. The results place ferromagnetic films with biphase magnetic behavior exhibiting asymmetric magnetoimpedance effect as a very attractive candidate for application as probe element in the development of auto-biased linear magnetic field sensors.Comment: 5 figure

The Signature Triality of Majorana-Weyl Spacetimes

Higher dimensional Majorana-Weyl spacetimes present space-time dualities which are induced by the Spin(8) triality automorphisms. Different signature versions of theories such as 10-dimensional SYM's, superstrings, five-branes, F-theory, are shown to be interconnected via the S_3 permutation group. Bilinear and trilinear invariants under space-time triality are introduced and their possible relevance in building models possessing a space-versus-time exchange symmetry is discussed. Moreover the Cartan's ``vector/chiral spinor/antichiral spinor" triality of SO(8) and SO(4,4) is analyzed in detail and explicit formulas are produced in a Majorana-Weyl basis. This paper is the extended version of hep-th/9907148.Comment: 28 pages, LaTex. Extended version of hep-th/990714

Gauge Theories with Lorentz-Symmetry Violation by Symplectic Projector Method

The violation of Lorentz symmetry is studied from the point of view of a canonical formulation. We make the usual analysis on the constraints structure of the Carroll-Field-Jackiw model. In this context we derive the equations of motion for the physical variables and check out the dispersion relations obtained from them. Therefore, by the analysis using Symplectic Projector Method (SPM), we can check the results about this type of Lorentz breaking with those in the recent literature: in this sense we can confirm that the configuration of $v^{\mu}$ space-like is stable, and the $v^{\mu}$ time-like carry tachionic modes.Comment: 7 pages and no figure

Torsion and Gravitation: A new view

According to the teleparallel equivalent of general relativity, curvature and torsion are two equivalent ways of describing the same gravitational field. Despite equivalent, however, they act differently: whereas curvature yields a geometric description, in which the concept of gravitational force is absent, torsion acts as a true gravitational force, quite similar to the Lorentz force of electrodynamics. As a consequence, the right-hand side of a spinless-particle equation of motion (which would represent a gravitational force) is always zero in the geometric description, but not in the teleparallel case. This means essentially that the gravitational coupling prescription can be minimal only in the geometric case. Relying on this property, a new gravitational coupling prescription in the presence of curvature and torsion is proposed. It is constructed in such a way to preserve the equivalence between curvature and torsion, and its basic property is to be equivalent with the usual coupling prescription of general relativity. According to this view, no new physics is connected with torsion, which appears as a mere alternative to curvature in the description of gravitation. An application of this formulation to the equations of motion of both a spinless and a spinning particle is madeComment: To appear on IJMP

Manejo da adubação verde para produção de mandioca em solo arenoso.

bitstream/CNPS-2010/14898/1/circtec32-2005-adubacao-verde.pd

Semeadura direta a lanço na reforma de pastagens degradadas no Estado do Acre.

Diante de um dos maiores problemas da Amazônia que é a degradação das pastagens, o presente estudo objetivou definir a melhor taxa e época de semeadura direta de Brachiaria brizantha cv. Xaraés em uma estratégia de plantio direto para reforma de pastagem. O delineamento experimental foi blocos casualizados com quatro repetições e os tratamentos arranjados em esquema fatorial 4x3, com quatro densidades de semeadura de B. brizantha cv. Xaraés (4, 8, 16 e 32 kg/ha de sementes puras germináveis) e três épocas de semeadura (1, 14 e 28 dias após a dessecação). O estande inicial da cv. Xaraés e plantas daninhas foram avaliados aos 28 dias após a semeadura. A composição botânica, altura do pasto e a massa seca dos componentes da pastagem, foram avaliados aos 98 dias após a semeadura. A semeadura um dia após a dessecação teve resultados muito ruins, com estande inicial de apenas 0,25 plântulas de cv. Xaraés por m² na primeira avaliação. A semeadura aos 14 dias resultou em uma pastagem com maior percentual da cv. Xaraés e menor percentagem de plantas daninhas na segunda avaliação. O estande de plantas da cv. Xaraés aos 28 dias após a semeadura aumentou linearmente com o aumento da densidade de semeadura. Dessa forma o melhor momento de semeadura direta da cv. Xaraés é aos 14 dias após a dessecação e um mínimo de 8 kg ha de sementes puras germináveis da cv. Xaraés é necessário para resultados satisfatórios na reforma de pastagens degradadas por este método no estado do Acre