Spin-1 Particles with Light-Front Approach

For the vector sector, i.e, mesons with spin-1, the electromagnetic form factors and anothers observables are calculated with the light-front approach. However, the light-front quantum field theory have some problems, for example, the rotational symmetry breaking. We solve that problem added the zero modes contribuition to the matrix elements of the electromagnetic current, besides the valence contribuition. We found that among the four independent matrix elements of the plus component in the light-front helicity basis only the $0\to 0$ one carries zero mode contributions.Comment: 5 pages. 3 Figures, use latex and EPJ styl

Electromagnetic Structure of the Pion

In this work, we analyze the electromagnetic structure of the pion. We calculate its electromagnetic radius and electromagnetic form factor in low and intermediate momentum range. Such observables are determined by means of a theoretical model that takes into account the constituent quark and antiquark of the pion within the formalism of light-front field theory. In particular, we consider a nonsymmetrical vertex in this model, with which we calculate the electromagnetic form factor of the pion in an optimized way, so that we obtain a value closer to the experimental charge radius of the pion. The theoretical calculations are also compared with the most recent experimental data involving the pion electromagnetic form factor and the results show very good agreement.Comment: Paper with 4 pages, 1 figure, presented in XII HADRON PHYSICS Conference - to appear in AIP Conference Proceeding

Verification of Magnitude and Phase Responses in Fixed-Point Digital Filters

In the digital signal processing (DSP) area, one of the most important tasks is digital filter design. Currently, this procedure is performed with the aid of computational tools, which generally assume filter coefficients represented with floating-point arithmetic. Nonetheless, during the implementation phase, which is often done in digital signal processors or field programmable gate arrays, the representation of the obtained coefficients can be carried out through integer or fixed-point arithmetic, which often results in unexpected behavior or even unstable filters. The present work addresses this issue and proposes a verification methodology based on the digital-system verifier (DSVerifier), with the goal of checking fixed-point digital filters w.r.t. implementation aspects. In particular, DSVerifier checks whether the number of bits used in coefficient representation will result in a filter with the same features specified during the design phase. Experimental results show that errors regarding frequency response and overflow are likely to be identified with the proposed methodology, which thus improves overall system's reliability

Herdabilidade dos escores da condição corporal de vacas ao parto e ao desmame em um rebanho da raça Canchim.

O objetivo desse trabalho foi estimar parâmetros genéticos e fenotípicos dos escores da condição corporal das vacas ao parto (ECCVP) e ao desmame (ECCVD) do bezerro em um rebanho da raça Canchim. Foram analisados os dados de 2.727 ECCVP e 1.328 ECCVD de 910 e 652 vacas, respectivamente, pertencentes à Embrapa Pecuária Sudeste. Os componentes de variância foram estimados por meio da Inferência Bayesiana, utilizando-se o Amostrador de Gibbs. Os ECCVP e ECCVD foram analisados por um modelo animal considerando os efeitos genético aditivo direto, de ambiente permanente do animal e residual como aleatórios, além dos efeitos fixos de grupo de contemporâneas (ano e mês de parto), sexo do bezerro e a idade da vaca (em anos) como covariável (efeitos linear e quadrático). As médias posteriores para a herdabilidade e para a proporção da variância de ambiente permanente para o ECCVP (0,19 e 0,04, respectivamente) e ECCVD (0,29 e 0,02, respectivamente) indicam que existe variância genética aditiva que pode justificar a inclusão dessas características como critérios de seleção e que o efeito de ambiente temporário (residual) é responsável pela maior parte da variância fenotípica