151 resultados para Negative dimensional integration method (NDIM)


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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Using the numerical solution of the nonlinear Schrodinger equation and a variational method it is shown that (3 + 1)-dimensional spatiotemporal optical solitons can be stabilized by a rapidly oscillating dispersion coefficient in a Kerr medium with cubic nonlinearity. This has immediate consequence in generating dispersion-managed robust optical soliton in communication as well as possible stabilized Bose-Einstein condensates in periodic optical-lattice potential via an effective-mass formulation. We also critically compare the present stabilization with that obtained by a rapid sinusoidal oscillation of the Kerr nonlinearity parameter.

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We use the time-dependent mean-field Cross-Pitaevskii equation to study the formation of a dynamically-stabilized dissipation managed bright soliton in a quasi-one dimensional Bose-Einstein condensate (BEC). Because of three-body recombination of bosonic atoms to molecules, atoms are lost (dissipated) from a BEC. Such dissipation leads to the decay of a BEC soliton. We demonstrate by a perturbation procedure that an alimentation of atoms from an external source to the BEC may compensate for the dissipation loss and lead to a dynamically-stabilized soliton. The result of the analytical perturbation method is in excellent agreement with mean-field numerics. It seems possible to obtain such a dynamically stabilized BEC soliton without dissipation in laboratory.

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In this paper, we study the travelling wave reductions for certain (2 + 1)- and (3 + 1)-dimensional physically important nonlinear evolutionary equations by using the recently proposed Homogenous Balance Method (HBM). Through this analysis we explore certain new solutions for the equations we have studied. (C) 2001 Published by Elsevier B.V.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The first step toward the application of an effective non partial wave (PW) numerical approach to few-body atomic bound states has been taken. The two-body transition amplitude which appears in the kernel of three-dimensional Faddeev-Yakubovsky integral equations is calculated as function of two-body Jacobi momentum vectors, i.e. as a function of the magnitude of initial and final momentum vectors and the angle between them. For numerical calculation the realistic interatomic interactions HFDHE2, HFD-B, LM2M2 and TTY are used. The angular and momentum dependence of the fully off-shell transition amplitude is studied at negative energies. It has been numerically shown that, similar to the nuclear case, the transition amplitude exhibits a characteristic angular behavior in the vicinity of He-4 dimer pole.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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In this paper we discuss the algebraic construction of the mKdV hierarchy in terms of an affine Lie algebra (s) over capl(2). An interesting novelty araises from the negative even grade sector of the affine algebra leading to nonlinear integro-differential equations admiting non-trivial vacuum configuration. These solitons solutions are constructed systematically from generalization of the dressing method based on non zero vacua. The sub-hierarchies admiting such class of solutions are classified.

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One-dimensional nanostructures of KNbO3 have attracted a great interest in the scientific community, mainly because of their promising application as nanoelectromechanical systems (NEMS). However, the synthesis of KNbO3 structures becomes complex due to the natural tendency to form non-stoichiometric potassium niobates. In this context, we report on the crystallization of one-dimensional KNbO3 nanostructures through the reaction between Nb2O5 and KOH under microwave-assisted hydrothermal synthesis (M-H). The use of this synthesis method made possible a very fast synthesis of singlecrystalline powders. Based on SEM, TEM and XRD characterizations, the influence of the synthesis time and the reactants concentration in the structure and morphology of the resultant KNbO3 was established. The conditions that favor the crystallization of nanofingers were determined to be small amounts of Nb2O5 and short reaction times. (C) 2008 Elsevier B.V. All rights reserved.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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The generalized temperature integral I(m, x) appears in non-isothermal kinetic analysis when the frequency factor depends on the temperature. A procedure based on Gaussian quadrature to obtain analytical approximations for the integral I(m, x) was proposed. The results showed good agreement between the obtained approximation values and those obtained by numerical integration. Unless other approximations found in literature, the methodology presented in this paper can be easily generalized in order to obtain approximations with the maximum of accurate.

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JUSTIFICATIVA E OBJETIVOS: O conhecimento de indicadores de qualidade de vida (QV) relacionados à saúde bucal é especialmente relevante para a Odontologia considerando o impacto que as condições bucais podem provocar no bem estar psicológico e social. Estudos sobre aspectos psicossociais contribuem para maior integração da conduta clínica e assistencial, preocupação compartilhada com profissionais da saúde. Integrar as áreas de Psicologia e Odontologia quebrando paradigmas interdisciplinares e o interesse em conhecer os aspectos psicológicos dos pacientes, motivou a realização deste estudo. O objetivo deste estudo foi avaliar a QV dos pacientes com disfunção temporomandibular e/ou dor orofacial. MÉTODO: Foi aplicado o Questionário Genérico de Avaliação de Qualidade de Vida - Medical Outcomes Study 36 - Item Short Health Survey (SF-36) a 91 pacientes, que buscaram atendimento por apresentarem sinais e/ou sintomas de disfunção temporomandibular (DTM) e dor orofacial (DOF). O SF-36 avalia 8 domínios: capacidade funcional (CF), aspectos físicos (AF), dor, estado geral de saúde (EGS), saúde mental (SM), aspectos emocionais (AE), aspectos sociais (AS) e vitalidade (V). RESULTADOS: A análise estatística descritiva e inferencial pela Correlação de Pearson (p-valor < 0,05) demonstrou, com exceção da capacidade funcional (73,2), valores médios entre 50 e 64 para os demais domínios: AF - 57,6; Dor - 50; EGS - 54,5; V - 53,4; AS - 63,6; AE - 51,8; SM - 58. Considerando-se que a pontuação varia de 0 a 100, ou seja, do pior para o melhor estado de saúde, os valores médios foram baixos. Verificou-se correlação entre CF e EGS (p-valor 0,01), tendência de significância para dor e EGS (p-valor 0,07). CONCLUSÃO: Os aspectos dor e capacidade funcional interferem no estado geral de saúde; os pacientes com DTM e DOF sofreram impacto negativo na qualidade de vida pelo prejuízo dos aspectos físicos e mentais.

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Coagulase-negative staphylococci (CNS) species identification is still difficult for most clinical laboratories. The scheme proposed by Kloos and Schleifer and modified by Bannerman is the reference method used for the identification of staphylococcal species and subspecies; however, this method is relatively laborious for routine use since it requires the utilization of a large number of biochemical tests. The objective of the present study was to compare four methods, i.e., the reference method, the API Staph system (bioMérieux) and two methods modified from the reference method in our laboratory (simplified method and disk method), in the identification of 100 CNS strains. Compared to the reference method, the simplified method and disk method correctly identified 100 and 99% of the CNS species, respectively, while this rate was 84% for the API Staph system. Inaccurate identification by the API Staph method was observed for Staphylococcus epidermidis (2.2%), S. hominis (25%), S. haemolyticus (37.5%), and S. warneri (47.1%). The simplified method using the simple identification scheme proposed in the present study was found to be efficient for all strains tested, with 100% sensitivity and specificity and proved to be available alternative for the identification of staphylococci, offering, higher reliability and lower cost than the currently available commercial systems. This method would be very useful in clinical microbiology laboratory, especially in places with limited resources.