Exact solution for the energy density inside a one-dimensional non-static cavity with an arbitrary initial field state

We study the exact solution for the energy density of a real massless scalar field in a two-dimensional spacetime, inside a non-static cavity with an arbitrary initial field state, taking into account the Neumann and Dirichlet boundary conditions. This work generalizes the exact solution proposed by Cole and Schieve in the context of the Dirichlet boundary condition and vacuum as the initial state. We investigate diagonal states, examining the vacuum and thermal field as particular cases. We also study non-diagonal initial field states, taking as examples the coherent and Schrodinger cat states.Comment: 10 pages, 8 figure

Bioclimatologia aplicada à produção de bovinos leiteiros nos trópicos.

bitstream/item/78361/1/documento-188.pd

Geometric scaling of purely-elastic flow instabilities

We present a combined experimental, numerical and theoretical investigation of the geometric scaling of the onset of a purely-elastic flow instability in a serpentine channel. Good qualitative agreement is obtained between experiments, using dilute solutions of flexible polymers in microfluidic devices, and two-dimensional numerical simulations using the UCM model. The results are confirmed by a simple theoretical analysis, based on the dimensionless criterion proposed by Pakdel-McKinley for onset of a purely-elastic instability

Diagnóstico sorológico de Brucella ovis em ovinos do Estado da Paraíba.

Resumo: A Brucelose ovina, causada pela Brucella ovis, é responsável por perdas econômicas, principalmente na fertilidade do rebanho. Foi realizado um levantamento sorológico em ovinos procedentes de duas mesorregiões do Estado da Paraíba. Foram examinadas 240 amostras séricas de animais pertencentes a 24 propriedades de oito municípios. As amostras foram testadas pela técnica de imunodifusão em gel de ágar (IDGA). Dos 240 animais investigados, 13 (5,4%) apresentaram resultados positivos para Brucella ovis. Das propriedades analisadas, 45,8% (11/24) possuíam, pelo menos, um animal soropositivo. Os resultados obtidos neste trabalho são indícios de que a infecção por Brucella ovis encontra-se presente nos ovinos das duas mesorregiões do Estado da Paraíba, sendo necessária a adoção de medidas sanitárias para evitar a propagação da doença nos rebanhos. Abstract: Ovine Brucellosis, caused by Brucella ovis, is responsible for economic losses, especially in flock fertility. A serological survey was performed in two mesorregions of Paraíba State. 240 serum samples were examined from 24 sheep flocks belonged to eight different municipalities. Samples were tested by agar gel immunodiffusion technique (AGID). 13 of 240 (5.4%) animals tested were seropositive for Brucella ovis. 45.8% (11/24) of analyzed flocks had, at least, one seropositive animal. Those results suggest that the infection by Brucella ovis is present in ovine of two mesorregions of Paraíba State. So that, it is necessary to adopt sanitary measures to avoid the disease spread in livestock

The extended gaussian ensemble and metastabilities in the Blume-Capel model

The Blume-Capel model with infinite-range interactions presents analytical solutions in both canonical and microcanonical ensembles and therefore, its phase diagram is known in both ensembles. This model exhibits nonequivalent solutions and the microcanonical thermodynamical features present peculiar behaviors like nonconcave entropy, negative specific heat, and a jump in the thermodynamical temperature. Examples of nonequivalent ensembles are in general related to systems with long-range interactions that undergo canonical first-order phase transitions. Recently, the extended gaussian ensemble (EGE) solution was obtained for this model. The gaussian ensemble and its extended version can be considered as a regularization of the microcanonical ensemble. They are known to play the role of an interpolating ensemble between the microcanonical and the canonical ones. Here, we explicitly show how the microcanonical energy equilibrium states related to the metastable and unstable canonical solutions for the Blume-Capel model are recovered from EGE, which presents a concave "extended" entropy as a function of energy.Comment: 6 pages, 5 eps figures. Presented at the XI Latin American Workshop on Nonlinear Phenomena, October 05-09 (2009), B\'uzios (RJ), Brazil. To appear in JPC

Three-dimensional Continuum Radiative Transfer Images of a Molecular Cloud Core Evolution

We analyze a three-dimensional smoothed particle hydrodynamics simulation of an evolving and later collapsing pre-stellar core. Using a three-dimensional continuum radiative transfer program, we generate images at 7 micron, 15 micron, 175 micron, and 1.3 mm for different evolutionary times and viewing angles. We discuss the observability of the properties of pre-stellar cores for the different wavelengths. For examples of non-symmetric fragments, it is shown that, misleadingly, the density profiles derived from a one-dimensional analysis of the corresponding images are consistent with one-dimensional core evolution models. We conclude that one-dimensional modeling based on column density interpretation of images does not produce reliable structural information and that multidimensional modeling is required.Comment: accepted by ApJL, 4 pages, 4 figure

Large deviations for non-uniformly expanding maps

We obtain large deviation results for non-uniformly expanding maps with non-flat singularities or criticalities and for partially hyperbolic non-uniformly expanding attracting sets. That is, given a continuous function we consider its space average with respect to a physical measure and compare this with the time averages along orbits of the map, showing that the Lebesgue measure of the set of points whose time averages stay away from the space average decays to zero exponentially fast with the number of iterates involved. As easy by-products we deduce escape rates from subsets of the basins of physical measures for these types of maps. The rates of decay are naturally related to the metric entropy and pressure function of the system with respect to a family of equilibrium states. The corrections added to the published version of this text appear in bold; see last section for a list of changesComment: 36 pages, 1 figure. After many PhD students and colleagues having pointed several errors in the statements and proofs, this is a correction to published article answering those comments. List of main changes in a new last sectio

Twisted partial actions of Hopf algebras

In this work, the notion of a twisted partial Hopf action is introduced as a unified approach for twisted partial group actions, partial Hopf actions and twisted actions of Hopf algebras. The conditions on partial cocycles are established in order to construct partial crossed products, which are also related to partially cleft extensions of algebras. Examples are elaborated using algebraic groups

Manual de catalogação: descrição de recursos eletrônicos na Agência de Informação Embrapa: versão 1.2.

bitstream/CNPTIA/11030/1/doc53.pdfAcesso em 01 dez. 2005