Qualitative Analysis of Polycycles in Filippov Systems

In this paper, we are concerned about the qualitative behaviour of planar Filippov systems around some typical minimal sets, namely, polycycles. In the smooth context, a polycycle is a simple closed curve composed by a collection of singularities and regular orbits, inducing a first return map. Here, this concept is extended to Filippov systems by allowing typical singularities lying on the switching manifold. Our main goal consists in developing a method to investigate the unfolding of polycycles in Filippov systems. In addition, we applied this method to describe bifurcation diagrams of Filippov systems around certain polycycles

Fermion Helicity Flip in Weak Gravitational Fields

The helicity flip of a spin-${\textstyle \frac{1}{2}}$ Dirac particle interacting gravitationally with a scalar field is analyzed in the context of linearized quantum gravity. It is shown that massive fermions may have their helicity flipped by gravity, in opposition to massless fermions which preserve their helicity.Comment: RevTeX 3.0, 8 pages, 3 figures (available upon request), Preprint IFT-P.013/9

Semiclassical structure of chaotic resonance eigenfunctions

We study the resonance (or Gamow) eigenstates of open chaotic systems in the semiclassical limit, distinguishing between left and right eigenstates of the non-unitary quantum propagator, and also between short-lived and long-lived states. The long-lived left (right) eigenstates are shown to concentrate as $\hbar\to 0$ on the forward (backward) trapped set of the classical dynamics. The limit of a sequence of eigenstates $\{\psi(\hbar)\}_{\hbar\to 0}$ is found to exhibit a remarkably rich structure in phase space that depends on the corresponding limiting decay rate. These results are illustrated for the open baker map, for which the probability density in position space is observed to have self-similarity properties.Comment: 4 pages, 4 figures; some minor corrections, some changes in presentatio

INPE's crop survey program using combined LANDSAT and aircraft data

There are no author-identified significant results in this report

Gravitational Laser Back-Scattering

A possible way of producing gravitons in the laboratory is investigated. We evaluate the cross section electron + photon $\rightarrow$ electron + graviton in the framework of linearized gravitation, and analyse this reaction considering the photon coming either from a laser beam or from a Compton back-scattering process.Comment: 11 pages, 2 figures (available upon request), RevTeX, IFT-P.03/9

Stephanofilaria sp em bovinos do município de São Carlos, Estado de São Paulo.

Estudos clínicas e laboratórios em ulceras do tipo "Chagas de Verão" em bovinos do Município de São Carlos. Observou-se uma dermatite nodular ulcerativa na região da quartela, jarrete, cruz, cabeça, teta, paleta

Análise tecnológica, nutricional e sensorial de macarrão elaborado com farinha de trigo adicionada de farinha de feijão-guandu.

Foram produzidos macarrões tipo "padre nosso "utilizando farinha de trigo complementada com farinha de feijão-guandu nas proporções de 5, 10 e 15%. Os macarrões obtidos nos ensaios foram submetidos à avaliação através das determinações de umidade, acidez, teste de cozimento e análise sensorial. Foram desenvolvidos ensaios biológicos com ratos albinos para a avaliação da qualidade protéica das misturas empregadas na formulação do macarrão. Os valores encontrados, para os diferentes macarrões, para a umidade e acidez podem ser considerados normais e dentro da faixa de aceitação. Os dados obtidos nos testes de cozimento indicam que os macarrões testados são de qualidade média baixa. A análise biológica revelou que a melhor suplementação de aminoácidos ocorreu com a mistura contendo 5% farinha de feijão-guandu

Elastic transport through dangling-bond silicon wires on H passivated Si(100)

We evaluate the electron transmission through a dangling-bond wire on Si(100)-H (2x1). Finite wires are modelled by decoupling semi-infinite Si electrodes from the dangling-bond wire with passivating H atoms. The calculations are performed using density functional theory in a non-periodic geometry along the conduction direction. We also use Wannier functions to analyze our results and to build an effective tight-binding Hamiltonian that gives us enhanced insight in the electron scattering processes. We evaluate the transmission to the different solutions that are possible for the dangling-bond wires: Jahn-Teller distorted ones, as well as antiferromagnetic and ferromagnetic ones. The discretization of the electronic structure of the wires due to their finite size leads to interesting transmission properties that are fingerprints of the wire nature