1,302 research outputs found

    Asymptotic Discord and Entanglement of Non-Resonant Harmonic Oscillators in an Equilibrium Environment

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    In this work, we calculate the exact asymptotic quantum correlations between two interacting non-resonant harmonic oscillators in a common Ohmic bath. We derive \emph{analytical formulas} for the covariances, fully describing any Gaussian stationary state of the system, and use them to study discord and entanglement in the strong and weak dissipation regimes. We discuss the rich structure of the discord of the stationary separable states arising in the strong dissipation regime. Also under strong dissipation, when the modes are not mechanically coupled, these may entangle only through their interaction with the \emph{common} environment. Interestingly enough, this stationary entanglement is only present within a \emph{finite band of frequencies} and increases with the dissipation rate. In addition, robust entanglement between \emph{detuned} oscillators is observed at low temperature.Comment: 4 pages, 5 figures. References updated. Some changes made. Submitte

    Stress analysis of finite anisotropic plates with cutouts under displacement boundary conditions

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    XI CONGRESO NACIONAL DE MATERIALES COMPUESTOS. Celebrado en Móstoles los días 6, 7 y 8 de julio de 2015The aim of this article is to provide an analytical tool to estímate the stress concentration in anisotropic plates weakened by a circular or elliptical hole; it is achieved by developing Lekhnitskii formalism in order to allow fínite boundary effects to be added (original formulation considers infinite plates). Only membrane problem is herein considered, particularly when prescribed displacements are applied at externa! boundaries, which could simulate boundary conditions of a manhole structure between wing spars. A boundary collocation method in conjunction with a least squares approach is used to solve the problem.Ministerio de Economía y Competitividad de España DPT2012-3718

    A Statistical Approach for the Maximization of the Financial Benefits Yielded by a Large Set of MMFs and AEs

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    This article introduces a statistical approach for the maximization of the financial benefits yielded by software projects that have been broken down into a considerable number of minimum marketable features modules (MMFs) and architectural elements (AEs). As the statistical approach requires a polynomial computational effort to run and provides approximation solutions with an arbitrarily chosen degree of confidence, it allows managers and developers to be more confident about the rightness of the decisions they make with little additional computational effort

    Role of sleep duration and sleep-related problems in the metabolic syndrome among children and adolescents

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    Background: There is increasing recognition that sleep is a risk factor for metabolic syndrome (MetS). The aim of the present study was to analyze the relationship between self-reported sleep duration, sleep-related problems and the presence of MetS in children and adolescents from Bogotá, D.C., Colombia. Methods: This is a cross-sectional analysis from the FUPRECOL study (2014-15). Participants included 2779 (54.2% girls) youth from Bogota (Colombia). MetS was defined as the presence of ≥3 of the metabolic abnormalities (hyperglycemia, hypertriglyceridemia, low high-density lipoprotein cholesterol [HDL-c], hypertension, and increased waist circumference) according to the criteria of de Ferranti/Magge and colleges. Self-reported sleep duration and sleep-related problems were assessed with the BEARS questionnaire. Results: Logistic regression analysis showed that boys who meet recommended duration of sleep had a decreased risk of elevated blood glucose levels (Odds Ratio [OR] = 0.71, 95%CI [0.40-0.94]; p = 0.031) compared to boys who have short-long sleep duration. Also, compared to young without sleep problems, excessive sleepiness during the day was related to low HDL-c levels in boys (OR = 1.36, 95%CI [1.02-1.83] ; p = 0.036) and high triglyceride levels in girls (OR = 1.28, 95%CI [1.01-1.63]; p = 0.045). Girls with irregular sleep patterns had decreased HDL-c levels (OR = 0.71, 95%CI [0.55-0.91] ; p = 0.009). Conclusions: Recommended sleep duration was associated with a decreased risk of elevated fasting glucose levels in boys, and sleep problems was related to lower HDL-c in girls and higher triglyceride levels in boys. These findings suggested the clinical importance of improving sleep hygiene to reduce metabolic risk factors in children and adolescents

    Boron application in oxisols and responses of coffee plants

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    Estudou-se a resposta de mudas de cafeeiros à nutrição de B, em Latossolo Roxo Distrófico e em Latossolo Vermelho-Escuro Distrófico fase arenosa apresentando diferente capacidade de adsorção. Os tratamentos consistiram da adição de solução de ácido bórico (0,0; 0,5; 1,0; 2,0; 4,0 e 8,0 μg de Bml-1 ). Foram avaliados quatro métodos para extração de B dos solos: pasta de saturação; HCI 0,05 N; HCI 0,1 N; e HCI 0,05 N + H2 SO4 0,025 N. Os teores de B foram determinados pelo método com azometina-H. A adsorção de B pelos solos foi consistente com o mecanismo descrito pela isoterma de Langmuir, com exceção dos desvios observados quando a concentração de B na solução do solo foi superior a 4 μg ml-1 . A quantidade de B adsorvido aumentou com o pH. Determinou-se que a capacidade dos solos de adsorverem B depende da textura deles. As técnicas de extrato da saturação e da extração de HCI 0,05 N mostraram a melhor correlação com a absorção de B pelas plantas. Encontrou-se que os cafeeiros respondem somente ao B em solução e não são diretamente influenciados pelo B adsorvido.To determine whether plants respond to adsorved or soluble boron, coffee seedlings were grown in two oxisols, Dystrophic Dark-Red Latosol and Dystrophic Dusky Red Latosol, having  different boron adsorption capacities. Six solution concentrations were employed: 0.0, 0.5, 1.0, 2.0, 4.0 and 8.0 μg of Bml-1.  Four soil boron extraction techniques were evaluated: saturation extract, 0.05 N HCI,0.1 N HCI, and 0.05 N HCI + 0.025 N H2SO4 (Mehlich Solution). Boron proportion was determined by the azomethine-H method. Adsorption of boron by those soils was consistent with a mechanism described by the Langmuir equation, except that deviations occur at solution concentration greater than about 4 μg B/ml. The quantity of boron adsorbed increased with pH. Boron adsorption capacity of the soils has been found to depend on their texture. The saturation extract and 0,05 N HCI extration techniques showed the best correlation with total plant boron uptake. It was found that coffee plants respond only to boron in solution and are not directly influenced by adsorbed boron

    A nondigestion extraction method for boron in plant leaves

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    É descrito um procedimento analítico para o diagnóstico do estado nutricional de B em folhas de plantas por um método de extração sem digestão com a solução de HCl. A extração consistiu na adição de 20 ml de HCl 1N em tubos de ensaio contendo 400 mg do material vegetal, seguido por aquecimento a 80°C por 15 minutos, agitação por 60 minutos a 250 rpm e filtração. A seguir, transferiu- se uma alíquota de 5 ml do filtrado para tubos de ensaio de 200 ml, adicionaram-se 100 mg de carvão ativado, agitado por 15 minutos a 250 rpm e refiltrado. Os resultados foram comparados com aqueles obtidos por digestão seca. Os teores de B foram determinados pelo método colorimétrico com azomethina-H. Os resultados evidenciaram que ambos os métodos extraíram quantidades idênticas de B. A adsorção do B pelo carvão ativado em um meio-ácido foi desprezível. A presença do carvão ativado no extrato de folhas sem digestão promoveu a completa adsorção das substâncias solúveis interferentes na determinação colorimétrica de B a 420 nm, A precisão média da extração de B pelo método proposto foi de 1,54%.A nondigestion procedure using HCl for the extraction of B in plant tissues is described. Plant materials were treated with 1NHCl, heated at 80°C for 15 minutes, shaken at 250 rpm for 60 minutes, and filtered. Then, 5 ml of the extracted solution was treated with 100 mg of activated charcoal, shaken at 250 rpm for 15 minutes, and refiltered. Boron was determined by the colorimetric azomethine-H method. The results were compared with those obtained by dry-ashing method. B contents were determined by the colorimetric method with azomethine-H. The results have shown that both methods extracted identical quantities of B. B adsorption by activated-charcoal in an acid-medium was minimum. The presence of activated charcoal in the nondigested leaves extract carried out the complete adsorption of the soluble substances interfering with B colorimetric determination at 420 nm. The mean B extraction accuracy by the proposed method was 1.54 percent

    Tratamiento farmacológico de la emergencia Hipertensiva

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    Se presenta la emergencia hipertensiva desde varios puntos de vista. Se define la entidad, se abordaron las diferentes formas de presentación así como las causas que la producen. Se exponeel tratamiento de elección para cada complicación, con dosis, vía de administración y efectos adversos
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