Non-unitary representations of the SU(2) algebra in the Dirac equation with a Coulomb potential

A novel realization of the classical SU(2) algebra is introduced for the Dirac relativistic hydrogen atom defining a set of operators that, besides, allow the factorization of the problem. An extra phase is needed as a new variable in order to define the algebra. We take advantage of the operators to solve the Dirac equation using algebraic methods. To acomplish this, a similar path to the one used in the angular momentum case is employed; hence, the radial eigenfuntions calculated comprise non unitary representations of the algebra. One of the interesting properties of such non unitary representations is that they are not labeled by integer nor by half-integer numbers as happens in the usual angular momentum representation.Comment: 20 pages 1 eps figure in a single zipped file, submitted to J. Math. Phy

Programas de controle das mastites causadas por microrganismos contagiosos e do ambiente

Este trabalho foi elaborado com o objetivo de apresentar os conceitos em que se baseiam os programas de controle da mastite, em uso na maioria das indústrias leiteiras desenvolvidas. Foram abordados os fundamentos dos programas de controle, as características dos patógenos mais comuns, os fatores relacionados à ocorrência da doença e a síntese do programa de controle. Destina-se prioritariamente a médicos veterinários e estudantes, embora outros profissionais e produtores interessados no tema possam também usá-lo.bitstream/item/81916/1/Programas-de-controle-das-mastites.pd

Analytical Multi-kinks in smooth potentials

In this work we present an approach which can be systematically used to construct nonlinear systems possessing analytical multi-kink profile configurations. In contrast with previous approaches to the problem, we are able to do it by using field potentials which are considerably smoother than the ones of Doubly Quadratic family of potentials. This is done without losing the capacity of writing exact analytical solutions. The resulting field configurations can be applied to the study of problems from condensed matter to brane world scenarios

Rinite atrófica dos suínos: alternativas de controle.

bitstream/item/59363/1/CUsersPiazzonDocuments3.pd

New Green-Kubo formulas for transport coefficients in hard sphere-, Langevin fluids and the likes

We present generalized Green-Kubo expressions for thermal transport coefficients $\mu$ in non-conservative fluid-type systems, of the generic form, $\mu$ $= \mu_\infty$ +\int^\infty_0 dt V^{-1} \av{I_\epsilon \exp(t {\cal L}) I}_0 where $\exp(t{\cal L})$ is a pseudo-streaming operator. It consists of a sum of an instantaneous transport coefficient $\mu_\infty$, and a time integral over a time correlation function in a state of thermal equilibrium between a current $I$ and its conjugate current $I_\epsilon$. This formula with $\mu_\infty \neq 0$ and $I_\epsilon \neq I$ covers vastly different systems, such as strongly repulsive elastic interactions in hard sphere fluids, weakly interacting Langevin fluids with dissipative and stochastic interactions satisfying detailed balance conditions, and "the likes", defined in the text. For conservative systems the results reduce to the standard formulas.Comment: 7 pages, no figures. Version 2: changes in the text and references adde

Verruga-das-folhas-do-cajueiro no Estado do Amapá.

O trabalho objetiva registrar a ocorrência de Contarinia sp. no Estado do Amapá, apresentar informações sobre a praga e seu controle, além de prestar esclarecimento sobre a sua importância na cultura do cajueiro.bitstream/item/96797/1/CPAF-AP-2003-Verruga-cajueiro.pd

Right atrium crossover

info:eu-repo/semantics/publishedVersio