942 resultados para State Extension Problem
Resumo:
The homogeneous Lippmann-Schwinger integral equation is solved in momentum space by using confining potentials. Since the confining potentials are unbounded at large distances, they lead to a singularity at small momentum. In order to remove the singularity of the kernel of the integral equation, a regularized form of the potentials is used. As an application of the method, the mass spectra of heavy quarkonia, mesons consisting from heavy quark and antiquark (Υ(bb̄), ψ(cc̄)), are calculated for linear and quadratic confining potentials. The results are in good agreement with configuration space and experimental results. © 2010 American Institute of Physics.
Resumo:
We present the first record of Odontophrynus carvalhoi for the state of Alagoas, Brazil, and a distribution map for this species. This new record represents the nearest location to the Brazilian coast known for this species. © 2010 Check List and Authors.
Resumo:
This article presents and discusses necessary conditions of optimality for infinite horizon dynamic optimization problems with inequality state constraints and set inclusion constraints at both endpoints of the trajectory. The cost functional depends on the state variable at the final time, and the dynamics are given by a differential inclusion. Moreover, the optimization is carried out over asymptotically convergent state trajectories. The novelty of the proposed optimality conditions for this class of problems is that the boundary condition of the adjoint variable is given as a weak directional inclusion at infinity. This improves on the currently available necessary conditions of optimality for infinite horizon problems. © 2011 IEEE.
Resumo:
Here, a simplified dynamical model of a magnetically levitated body is considered. The origin of an inertial Cartesian reference frame is set at the pivot point of the pendulum on the levitated body in its static equilibrium state (ie, the gap between the magnet on the base and the magnet on the body, in this state). The governing equations of motion has been derived and the characteristic feature of the strategy is the exploitation of the nonlinear effect of the inertial force associated, with the motion of a pendulum-type vibration absorber driven, by an appropriate control torque [4]. In the present paper, we analyzed the nonlinear dynamics of problem, discussed the energy transfer between the main system and the pendulum in time, and developed State Dependent Riccati Equation (SDRE) control design to reducing the unstable oscillatory movement of the magnetically levitated body to a stable fixed point. The simulations results showed the effectiveness of the (SDRE) control design. Copyright © 2011 by ASME.
Resumo:
This paper addresses the H ∞ state-feedback control design problem of discretetime Markov jump linear systems. First, under the assumption that the Markov parameter is measured, the main contribution is on the LMI characterization of all linear feedback controllers such that the closed loop output remains bounded by a given norm level. This results allows the robust controller design to deal with convex bounded parameter uncertainty, probability uncertainty and cluster availability of the Markov mode. For partly unknown transition probabilities, the proposed design problem is proved to be less conservative than one available in the current literature. An example is solved for illustration and comparisons. © 2011 IFAC.
Resumo:
This paper deals with the problem of establishing stabilizing state-dependent switching laws in DC-DC converters operating at continuous conduction mode (CCM) and comparing their performance indexes. Firstly, the nature of the problem is defined, that is, the study of switched affine systems, which may not share a common equilibrium point. The concept of stability is, therefore, broadened. Then, the central theorem is proposed, from which a family of switching laws can be derived, namely the minimum law and the hold state law. Some of these are proved to stabilize the basic DC-DC converters and then, their performances are compared to another law, from a previous work, by simulation, where a great reduction in overshoot is obtained. © 2011 IEEE.
Resumo:
Background: Low birth weight (LBW), defined as birth weight less than 2500 g, has a complex etiology and may be a result of premature interruption of pregnancy or intrauterine growth restriction. The objective of this study was to provide information on determinants of LBW and contribute to the understanding of the problem in Brazil. Methods. A case-control study was conducted in Botucatu city, SP state, Brazil. The study population consisted of 2 groups with 860 newborns in each group as follows: low weight newborns (LWNB) and a control group (weight ≤ 2500 g). Secondary data from 2004 to 2008 were collected using the Live Birth Certificate (LBC) and records from medical charts of pregnant women in Basic Health Units (BHU) and in the Public University Hospital (UH). Variables were as follows: maternal socio-demographic characteristics, pregnancy and birth conditions including quality of prenatal care according to 3 criteria. They were based on parameters established by the Ministry of Health (MH), one of them, the modified Kessner Index. The multivariable analysis by logistic regression was used to evaluate the association between variables and LBW. Results: According to the analysis, the factors associated with LBW were as follows: prematurity (OR = 56.98, 95% CI 29.52-109.95), twin pregnancy (OR = 20.00, 95% CI 6.25-100.00), maternal smoking (OR = 2.12, 95% CI 1.33-3.45), maternal malnourishment (OR = 2.30, 95% CI 1.08-5.00), maternal obesity (OR = 2.30, 95% IC 1.18-4.48), weight gain during pregnancy less than 5 kg (OR = 2.63, 95% CI 1.35-5.00) and weight gain during pregnancy more than 15 kg (OR = 2.26, 95% CI 1.16-4.41). Adequacy of prenatal care visits adjusted to gestational age was less frequent in the LBW group than in the control group (68.7% vs. 80.5%, x 2 p < 0.001). According to the modified Kessner Index, 64.4% of prenatal visits in the LWNB group were adequate. Conclusion: LWNB are a quite heterogeneous group of infants concerning their determinants and prevention actions against LBW and the follow-up of these infants have also been very complex. Therefore, improvement in the quality of care provided should be given priority through concrete actions for prevention of LBW. © 2012 Fonseca et al; licensee BioMed Central Ltd.
Resumo:
Erythroxylaceae have tropical and subtropical distribution with four genera and about 250 species. Erythroxylum is the biggest genus of the family with approximately 100 species cited for Brazil. Erythroxylum subsessile (Mart.) O.E. Schulz is a species cited just for Rio de Janeiro state and now first recorded for the state of Espírito Santo, increasing its area of distribution. © 2012 Check List and Authors.
Resumo:
Includes bibliography
Resumo:
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Resumo:
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Resumo:
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Resumo:
The Economic Commission for Latin America and the Caribbean (ECLAC) jointly with the World Program of Food (WFP) and recognized experts of the region developed a methodology that, using secondary information, estimate the opportunity cost derived from undernutrition. This methodology has been successfully applied in Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua, Panama and the Dominican Republic, where the cost of undernutrition was estimated at 6.7 billion dollars in 2004. The present study covers four countries in South America: Bolivia, Ecuador, Paraguay and Peru. The results indicate that the cost of the malnutrition in these countries reached 4.3 billion dollars in 2005, which is equivalent to 3.3 per cent of the GDP of these countries. The results strongly point out that child undernutrition is not only a problem of health or an unacceptable situation ethically, but it is a national problem, given the enormous social costs and the loss of opportunities that it imposes on the national economy.
Resumo:
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Resumo:
Apesar das demandas e pressão da sociedade civil e dos próprios trabalhadores no sentido de fazer valer uma Política de Combate ao Trabalho Escravo que, existe desde a década de noventa do século passado no Brasil, todavia, identifica-se, em pleno século XXI, a existência de trabalho escravo, que coloca em evidência o problema da ausência de direitos humanos e sociais, assim como a fragilidade da construção da democracia e da cidadania na sociedade brasileira. Para compreender a política de combate ao trabalho escravo no Brasil, parte-se de um referencial crítico de análise que compreende a política pública como um desdobramento da relação Estado e sociedade na sociedade capitalista e, apoiado, em autores da tradição marxista, faz-se um percurso teórico-metodológico, que abrange desde a constituição do Estado oligárquico brasileiro, na época da escravidão colonial, até o surgimento de novas formas de trabalho escravo contemporâneo, com conteúdos semelhantes às antigas práticas sociais. Desta forma, a pesquisa apresenta uma análise das convergências e divergências, por parte dos executores, na operacionalização da Política de Combate ao Trabalho Escravo, materializada no II Plano Nacional para Erradicação do Trabalho Escravo, criado em 2008. Ressalta-se na operacionalização da política, ambiguidades e ambivalências da própria constituição do Estado capitalista brasileiro, que através das políticas públicas media interesses que são “inconciliáveis”. Essas ambiguidades e ambivalências do Estado se traduzem nas divergências e convergências dos executores da política, tal fato se apresenta como um limite ao funcionamento da política e contribui para a reincidência dos trabalhadores ao trabalho escravo contemporâneo. Ao mesmo tempo, reflete um Estado pactual que ao tomar a sua posição junto aos “donos do poder”, não dispõe de instrumental para que estes direitos sejam cumpridos através da política. Assim sendo, apesar dos avanços, a política de combate ao trabalho escravo no Brasil apresenta-se como uma exigência transnacional para se manter a política da “boa vizinhança” do que a efetivação da promoção da condição de cidadão para os que dela necessitam, não passa de um simulacro de civilidade que visa manter uma imagem de país democrático e disposto a resolver as causas dos direitos humanos quando na verdade mantém uma política interna cruel que reforça as condições de exploração desse tipo de trabalho.