939 resultados para self-consistent-field
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The soybean cyst nematode (Heterodera glycines) has become an increasingly severe problem in soybean production areas in Brazil. The development and use of resistant cultivars is the most efficient method of minimizing losses due to this pathogen. Our objective was to test the efficiency of an alternative method for screening soybean genotypes for resistance to H. glycines in field plots. The alternative method was compared to the standard method of sowing the test genotypes in fields found to be infested during the previous crop season. In the alternative method, the test genotypes are sown in the furrow following the uprooting of 45-day-old infected plants. The alternative method resulted in twice the cyst population and fewer escapes, and more consistent results than the standard method. The major advantage of the alternative method is that it permits screening in a more homogeneous distribution of H. glycines in the soil.
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In the present paper we introduce a hierarchical class of self-dual models in three dimensions, inspired in the original self-dual theory of Towsend-Pilch-Nieuwenhuizen. The basic strategy is to explore the powerful property of the duality transformations in order to generate a new field. The generalized propagator can be written in terms of the primitive one (first order), and also the respective order and disorder correlation functions. Some conclusions about the charge screening and magnetic flux were established. ©1999 The American Physical Society.
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Considering the ferromagnetic screening for the decay of the X-ray neutron star magnetic field in the binary accretion phase, the phase transition of ferromagnetic materials in the crust of neutron star induces the ferromagnetic screening saturation of the accreted crust, which results in the minimum surface magnetic field of the accreting neutron star, about 108 G, if the accreted matter has completely replaced the crust mass of the neutron star. The magnetic field evolution versus accreted mass is given as Bs ∝ ΔM-0.9, and the obtained magnetic field versus spin period relation is consistent with the distribution of the binary X-ray sources and recycled pulsars. The further thermal effect on the magnetic evolution is also studied.
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It has been conjectured that at the stationary point of the tachyon potential for the D-brane-anti-D-brane pair or for the non-BPS D-brane of superstring theories, the negative energy density cancels the brane tensions. We study this conjecture using a Wess-Zumino-Witten-like open superstring field theory free of contact term divergences and recently shown to give 60% of the vacuum energy by condensation of the tachyon field alone. While the action is non-polynomial, the multiscalar tachyon potential to any fixed level involves only a finite number of interactions. We compute this potential to level three, obtaining 85% of the expected vacuum energy, a result consistent with convergence that can also be viewed as a successful test of the string field theory. The resulting effective tachyon potential is bounded below and has two degenerate global minima. We calculate the energy density of the kink solution interpolating between these minima finding good agreement with the tension of the D-brane of one lower dimension. © 2000 Elsevier Science B.V.
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In this work we prove in a precise way that the soldering formalism can be applied to the Srivastava chiral boson (SCB), in contradiction with some results appearing in the literature. We promote a canonical transformation that shows directly that the SCB is composed of two Floreanini-Jackiw particles with the same chirality in which the spectrum is a vacuumlike one. As another conflicting result, we prove that a Wess-Zumino (WZ) term used in the literature consists of a scalar field, once again denying the assertion that the WZ term adds a new degree of freedom to the SCB theory in order to modify the physics of the system. © 2001 The American Physical Society.
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We complete the construction of the Neveu-Schwarz sector of heterotic string field theory begun in [9] by giving a closed-form expression for the action and gauge transformations. Just as the Wess-Zumino-Witten (WZW) action for open superstring field theory can be constructed from pure-gauge fields in bosonic open string field theory, our heterotic string field theory action is constructed from pure-gauge fields in bosonic closed string field theory. The construction involves a simple alternative form of the WZW action which is consistent with the algebraic structures of closed string field theory. © SISSA/ISAS 2004.
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We report the use of organic-inorganic sol-gel derived poly(oxyehylene)/ siloxane hybrid doped with methacrylic acid modified zirconium (IV) n-propoxide for the fabrication of low cost waveguides trough direct UV laser writing. The organic-inorganic hybrids were processed as monoliths with size and shape control. The effective guiding region was identified and the number of modes was estimated via mode field analyses. A grating was successfully superimposed on the channel and the respective reflection spectrum was measured, enabling the determination of the guiding region dimension, the calculation of the effective refractive index of the guided mode. © 2007 IEEE.
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The measurement of the phase shift φ between the transmited and difracted beams interfering along the same direction behind the hologram recorded in a photorefractive crystal is directly and accurately measured using a self-stabilized recording technique. The measured phase shift as a function of the applied electric field allows computing the Debye screening lenght and the effectively applied field coefficient of an undoped Bi 12TiO 20 crystal. The result is in good agreement with the already available information about this sample. © 2008 American Institute of Physics.
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The presence of porosities at the dentin/adhesive interface has been observed with the use of new generation dentin bonding systems. These porosities tend to contradict the concept that etching and hybridization processes occur equally and simultaneously. Therefore, the aim of this study was to evaluate the micromechanical behavior of the hybrid layer (HL) with voids based on a self-etching adhesive system using 3-D finite element (FE) analysis. Three FE models (Mr) were built: Mr, dentin specimen (41x41x82 μm) with a regular and perfect (i.e. pore-free) HL based on a self-etching adhesive system, restored with composite resin; Mp, similar to M, but containing 25% (v/v) voids in the HL; Mpp, similar to Mr, but containing 50% (v/v) voids in the HL. A tensile load (0.03N) was applied on top of the composite resin. The stress field was obtained by using Ansys Workbench 10.0. The nodes of the base of the specimen were constrained in the x, y and z axes. The maximum principal stress (σmax) was obtained for all structures at the dentin/adhesive interface. The Mpp showed the highest peak of σmax in the HL (32.2 MPa), followed by Mp (30 MPa) and Mr (28.4 MPa). The stress concentration in the peritubular dentin was high in all models (120 MPa). All other structures positioned far from voids showed similar increase of stress. Voids incorporated into the HL raised the σmax in this region by 13.5%. This behavior might be responsible for lower bond strengths of self-etching and single-bottle adhesives, as reported in the literature.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Pós-graduação em Música - IA
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INTRODUÇÃO: O Programa HIPERDIA foi implantado em 2001 na atenção básica devido à gravidade epidemiológica da Hipertensão Arterial Sistêmica (HAS) e o Diabetes Mellitus (DM), afecções que podem acarretar sérias complicações incutindo limitações e sofrimento na vida de seus portadores e suas famílias. Nesse contexto, ressalte-se a importância da prevenção primária dessas afecções e de suas complicações. Passado mais de uma década de sua implementação, cabe refletir acerca do impacto nas condições de saúde que o Programa tem gerado entre seus usuários. OBJETIVOS: Elucidar os princípios, a filosofia e a política norteadora do Programa HIPERDIA do Ministério da Saúde (MS); descrever como funciona o atendimento do usuário pela equipe de saúde de um Programa HIPERDIA; explorar os comportamentos de vida e saúde demonstrados pelos usuários do HIPERDIA após sua inserção no Programa. DESCRIÇÃO METODOLÓGICA: Trata-se de um Estudo de Caso segundo Yin (2010) cujo objeto de estudo foi um Programa HIPERDIA executado numa Unidade Básica de Saúde da periferia de Belém-PA. Os dados foram obtidos por meio de entrevista com usuários, equipe e gestores do Programa, além da observação direta do campo, consulta de prontuários e da documentação oficial do MS. A análise dos dados obtidos foi feita por meio da estratégia analítica “Contando com Proposições Teóricas” e da técnica analítica “Combinação de Padrão”. RESULTADOS: A precarização da gestão do Programa HIPERDIA ilustrada por deficiências na infraestrutura, insumos, medicamentos e fragilidades na rede de referência e contrarreferência, a demanda espontânea excessiva que sobrecarrega a equipe de saúde alocada em número insuficiente e o contexto de pobreza e violência urbana em que os usuários vivem contribuem para a baixa adesão ao regime terapêutico e limitam a equipe em sua atuação interdisciplinar e integral. Ademais, o modelo de atenção vigente é pautado no tradicional, baseado em consultas e prescrições e que não tem se demonstrado suficiente para atender integralmente às necessidades de atenção ao portador de condição crônica, que requer cuidados prolongados com adoção de estilos de vida mais condizentes e saudáveis. CONSIDERAÇÕES FINAIS: Grandes desafios se desenham diante dos dados emergidos deste estudo e envolvem ações macrogovernamentais e intersetoriais que promovam melhorias nas condições de vida da população o que requer vontade política para investimento dos recursos necessários. Não obstante a isso, a enfermagem pode dar sua contribuição promovendo cuidado cultural e ações de autocuidado, personalizando o plano de ação e trazendo a corresponsabilidade do usuário e sua família na melhoria de sua condição de saúde.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Our conception of education is that it is the responsible action whereby man becomes human, trains and faces the challenges that life and the world present, as man enters a larger, shared cultural tradition and thus joins the world. However such sharing implies that we must not just rely on tradition, but remain open to new ideas. It is essential for schooling to preserve a field where the art of living intersects with the world for which future generations are being prepared. It is in this field of intersection that this essay seeks to discuss Michel Foucault's thought, care of the self and the role played by others in the acquisition of ethical attitudes pertaining to one's conduct in life. Through reconstructing Foucault's ideas, we elaborate on the hypothesis that, before morally shaping students, teaching them values, or aiding in their skill acquisition in the sense prevailing in schooling today, it is important to understand the notion of care of the self (and how the notion implies interaction with others for effective care of the self). Care of the self is vital for thoroughly understanding the relationships between ethics and education in school. We particularly examine how Foucault's ideas and his analysis of the teacher's role in shaping the student's life conduct can help educators rethink pedagogical action in an ethical sense and find within it a certain openness to the formation of attitudes in educators and students
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)