1,007 research outputs found

    Correlation exponent K_rho of the one-dimensional Kondo lattice model

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    We present results for the correlation exponent K_rho of the Tomonaga-Luttinger liquid description of the one-dimensional Kondo lattice as a function of conduction electron density and coupling constant. It is obtained from the first derivative of the Fourier transform of the charge-charge correlation function. We also show that the spin correlation function can only be described in this picture if we include logarithmic corrections, a feature that had been previously overlooked. A consistent description of both charge and spin sectors is then obtained. Finally, we show evidence that the spin sector of the dimerized phase at quarter-filling is gapless.Comment: 5 pages, 6 figure

    Gravidez na adolescência

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    Beneficios en la microbiota intestinal después de la suplementación con inulina y la goma guar parcialmente hidrolizada: un ensayo clínico aleatorizado en mujeres con estreñimiento

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    Introduction: Prebiotics positively affect gut microbiota composition, thus improving gut function. These properties may be useful for the treatment of constipation.Objectives: This study assessed the tolerance and effectiveness of a prebiotic inulin/partially hydrolyzed guar gum mixture (I-PHGG) for the treatment of constipation in females, as well as its influence on the composition of intestinal microbiota and production of short chain fatty acids.Methods: Our study enrolled 60 constipated female health worker volunteers. Participants reported less than 3 bowel movements per week. Volunteers were randomized to treatment with prebiotic or placebo. Treatment consisted of 3 weeks supplementation with 15 g/d I-PHGG (fiber group) or maltodextrin (placebo group). Abdominal discomfort, flatulence, stool consistency, and bowel movements were evaluated by a recorded daily questionnaire and a weekly interview. Changes in fecal bacterial population and short chain fatty acids were assessed by real-time PCR and gas chromatography, respectively.Results: There was an increased frequency of weekly bowel movements and patient satisfaction in both the fiber and placebo groups with no significant differences. Total Clostridium sp significantly decreased in the fiber group (p = 0.046) and increased in the placebo group (p = 0.047). There were no changes in fecal short chain fatty acid profile.Conclusions: Consumption of I-PHGG produced clinical results comparable to placebo in constipated females, but had additional protective effects on gut rnicrobiota by decreasing the amount of pathological bacteria of the Clostridium genera.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Univ São Paulo, Fac Med, Sch Med, Dept Gastroenterol,Surg Gastroenterol Discipline, BR-01246903 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Biociences, Santos, BrazilGANEP Nutr Humana, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Biociences, Santos, BrazilFAPESP: 07/58600-2Web of Scienc

    Sistemas de produção praticados e sistemas melhorados propostos - Bacia do Rio Formoso, Bonito, MS.

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    O presente trabalho faz parte do Projeto "Gestão Integrada da Bacia Hidrográfica do Rio Formoso", financiado pelo Fundo para o Meio Ambiente Mundial (Global Environment Facility - GEF) e implementado pelo Banco Internacional para a Reconstrução e o Desenvolvimento (Bird). O objetivo deste trabalho foi de caracterizar os sistemas de produção modais (predominantes) praticados pelos produtores rurais da Bacia do Rio Formoso, Bonito, MS e a partir destes, propor sistemas melhorados, mais sustentáveis. As informações para a caracterização de cada sistema foram levantadas por meio de painéis participativos, com a presença de técnicos, pesquisadores, produtores rurais e outros interessados. Foram realizados em 2006, quatro painéis para caracterização dos sistemas modais e outros quatro para proposição dos melhorados. Foram contemplados no estudo os sistemas de produção de gado de leite, gado de corte, agricultura familiar (mandioca de mesa, cana-de-açúcar para rapadura, galinha caipira de corte, suínos, hortaliças e abelha melífera) e agricultura empresarial (produção de grãos). A proposição de sistemas melhorados visa a subsidiar as atividades de planejamento das ações de intervenção nas microbacias, contempladas em outras atividades do projeto.bitstream/CNPGC-2009-09/12412/1/DOC164.pd

    Confusing the extragalactic neutrino flux limit with a neutrino propagation limit

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    We study the possible suppression of the extragalactic neutrino flux due to a nonstandard interaction during its propagation. In particular, we study neutrino interaction with an ultra-light scalar field dark matter. It is shown that the extragalactic neutrino flux may be suppressed by such an interaction, leading to a new mechanism to reduce the ultra-high energy neutrino flux. We study both the cases of non-self-conjugate as well as self-conjugate dark matter. In the first case, the suppression is independent of the neutrino and dark matter masses. We conclude that care must be taken when explaining limits on the neutrino flux through source acceleration mechanisms only, since there could be other mechanisms for the reduction of the neutrino flux.Comment: 15 pages, 4 figures. Important changes implemented. Abstract modified. Conclusions remain. To be published in JCA

    Distócia de ombros e lesão do plexo braquial: revisão e casuística 2012

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    In this paper, we investigate the realization problem of a special class of positive-real admittances in a form similar to biquadratic functions but with an extra pole at s = 0, which is common in vehicle suspension designs. The number of inerters and dampers is restricted to one in each case and number of the springs is arbitrary. To solve the problem, we first convert a previous result by Chen & Smith, 2009 to a more direct form. A necessary and sufficient condition for realizability is then derived and explicit circuit arrangements are provided to cover the realizability conditions. © 2012 IEEE.published_or_final_versio
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