2,764 research outputs found

    Non universality of entanglement convertibility

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    Recently, it has been suggested that operational properties connected to quantum computation can be alternative indicators of quantum phase transitions. In this work we systematically study these operational properties in 1D systems that present phase transitions of different orders. For this purpose, we evaluate the local convertibility between bipartite ground states. Our results suggest that the operational properties, related to non-analyticities of the entanglement spectrum, are good detectors of explicit symmetries of the model, but not necessarily of phase transitions. We also show that thermodynamically equivalent phases, such as Luttinger liquids, may display different convertibility properties depending on the underlying microscopic model.Comment: 5 pages + references, 4 figures - improved versio

    Branching in fluidic networks with permeable walls: an extension of Hess-Murray’s law

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    The branching of fluidic networks becomes a subject of great interest due to its importance in understanding the behavior of branching networks in biology (cardiovascular and bronchial systems, river basins, the structure of plants and trees, etc..), as well as for the biomimetic design of engineering systems [1, 2]. The successive division of tubes and their hierarchical structure are distinctive features of tree-shaped networks. As the network progresses, tubes become smaller, both in length and diameter with the successive division of tubes. The design of these networks is generally assumed as being described by the Hess-Murray’s law. This paper addresses a fundamental issue of distributing a fluid flow in a network of vessels with permeable walls

    Mapping of a Leishmania major gene/locus that confers pentamidine resistance by deletion and insertion of transposable element

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    Pentamidine (PEN) is an alternative compound to treat antimony-resistant leishmaniasis patients, which cellular target remains unclear. One approach to the identification of prospective targets is to identify genes able to mediate PEN resistance following overexpression. Starting from a genomic library of transfected parasites bearing a multicopy episomal cosmid vector containing wild-type Leishmania major DNA, we isolated one locus capable to render PEN resistance to wild type cells after DNA transfection. In order to map this Leishmania locus, cosmid insert was deleted by two successive sets of partial digestion with restriction enzymes, followed by transfection into wild type cells, overexpression, induction and functional tests in the presence of PEN. To determine the Leishmania gene related to PEN resistance, nucleotide sequencing experiments were done through insertion of the transposon Mariner element of Drosophila melanogaster (mosK) into the deleted insert to work as primer island. Using general molecular techniques, we described here this method that permits a quickly identification of a functional gene facilitating nucleotide sequence experiments from large DNA fragments. Followed experiments revealed the presence of a P-Glycoprotein gene in this locus which role in Leishmania metabolism has now been analyzed.A Pentamidina (PEN) é um composto alternativo para o tratamento de pacientes com leishmaniose que apresentam resistência ao antimônio, cujo alvo celular continua incerto. Uma abordagem para se identificar prováveis alvos seria a identificação e super-expressão de genes capazes de mediar resistência a PEN. A partir de uma genoteca construída com o DNA de Leishmania major em um vetor - cosmídio que se desenvolve tanto em bactérias como nas células do parasita, isolamos um locus que após transfecção é capaz de produzir resistência a PEN às células do parasita. Almejando o mapeamento desse locus de leishmania, o inserto clonado nesse cosmídio foi deletado através de duas digestões parciais sucessivas com enzimas de restrição, seguida de transfecção em células selvagens, super-expressão gênica, indução e testes funcionais na presença de PEN. Para determinar o gene de Leishmania relacionado com a resistência a PEN, o seqüenciamento de nucleotídeos foi executado após inserção de elementos transposicionais de Drosophila melanogaster no interior do inserto deletado para atuar como 'ilhas de iniciadores'. Descrevemos aqui o mapeamento desse locus, após a inserção transposicional, que além de facilitar o seqüenciamento de nucleotídeos de grandes fragmentos de DNA, permite uma rápida identificação do gene relacionado com esse fenótipo. Experimentos posteriores revelaram neste locus a presença do gene de uma Glicoproteína-P de membrana, cujo papel no metabolismo na Leishmania está sendo analisado

    Validade e confiabilidade do diâmetro abdominal sagital enquanto preditor de gordura abdominal visceral

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    OBJECTIVES: To evaluate the reliability of the sagittal abdominal diameter and its validity as a predictor of visceral abdominal fat, as well as to identify the most appropriate cut-off points to identify the area of visceral fat that is known to represent a risk factor for cardiovascular disease. DESIGN: Validation study. SUBJECTS: 92 healthy volunteers (57 women, 35 men), age: 20-83 y, body mass index: 19.3 to 35.9 kg/m². MEASUREMENTS: Sagittal abdominal diameter (SAD), weight, height, circumferences (waist, hip, and thigh), sub-scapular skinfold thickness, abdominal diameter index, and waist-hip ratio (WHR). METHOD OF CHOICE: Computed tomography (CT). STATISTIC: Receiver operating characteristic (ROC) curve. RESULTS: The reliability for SAD measurement was very high (Inter-class coefficient = 0.99). Visceral fat as measured by VAF through CT was highly correlated with SAD (women r = 0.80; men r = 0.64, p < 0.001), waist circumference (women r = 0.77; men r = 0.73, p < 0.001), and WHR (women r = 0.72; men r = 0.58, p < 0.001). The ROC curve indicated 19.3 cm and 20.5 cm as the threshold values for abdominal sagittal diameter in women and men (sensitivity 85% and 83%, specificity 77% and 82%, respectively). CONCLUSIONS: There was a high correlation between SAD and VAF. The cut-off values identified for SAD presented a sensitivity and specificity that were considered adequate.OBJETIVOS: Avaliar a confiabilidade do diâmetro abdominal sagital e a sua validade enquanto preditor de gordura abdominal visceral, assim como identificar os pontos de corte mais apropriados para identificar a área de gordura visceral que é conhecida por representar fator de risco para doença cardiovascular. MÉTODOS: Desenho: Estudo de validação. Amostra: 92 voluntários saudáveis (57 mulheres, 35 homens), idade: 20-83 anos, índice de massa corporal: 19,3 a 35,9 kg/m². Medidas: Diâmetro abdominal sagital (DAS), peso, altura, circunferências (cintura, quadril e coxa), pregas cutâneas tricipital e subescapular, índice diâmetro abdominal e razão cintura-quadril (RCQ). MÉTODO DE ESCOLHA: Tomografia computadorizada (TC). ESTATÍSTICA: Curva ROC (receiver operating characteristic). RESULTADOS: A confiabilidade do DAS foi muito alta (coeficiente inter-classe = 0,99). A área de gordura visceral medida pela TC teve uma alta correlação com o DAS (mulheres r = 0,80, homens r = 0,64, p < 0,001), circunferência da cintura (mulheres r = 0,77, homens r = 0,73, p < 0,001) e com a RCQ (mulheres r = 0,72, homens r = 0,58, p < 0,001). A curva ROC indicou 19,3 cm e 20,5 cm como valores limites para o diâmetro abdominal sagital em mulheres e homens (sensibilidade de 85% e 83%, especificidade de 77% e 82%, respectivamente). CONCLUSÕES: Observou-se alta correlação entre o DAS e a área de gordura abdominal visceral. Os pontos de corte identificados para o DAS apresentaram sensibilidade e especificidade adequadas.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Universidade Federal da Bahia Escola de Nutrição Departamento Ciência da NutriçãoUniversidade Federal de São Paulo (UNIFESP) Department of Health and Human Services of Centers for Disease Control and PreventionUniversidade Federal de São Paulo (UNIFESP) Departamento de Medicina PreventivaUNIFESP, Department of Health and Human Services of Centers for Disease Control and PreventionUNIFESP, Depto. de Medicina PreventivaSciEL

    Renormalizability of Nonrenormalizable Field Theories

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    We give a simple and elegant proof of the Equivalence Theorem, stating that two field theories related by nonlinear field transformations have the same S matrix. We are thus able to identify a subclass of nonrenormalizable field theories which are actually physically equivalent to renormalizable ones. Our strategy is to show by means of the BRS formalism that the "nonrenormalizable" part of such fake nonrenormalizable theories, is a kind of gauge fixing, being confined in the cohomologically trivial sector of the theory.Comment: 3 pages, revtex, no figure

    Methane emission from a flooded rice field under pre-germinated system.

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    Abstract: Local greenhouse gas flow measurement studies have been encouraged at a global level as a subsidy for national and state inventories. This study aimed to evaluate the seasonal methane emission during the 2008/2009 harvest, from an irrigated rice plantation, under pre-germinated system, in the municipality of Tremembé, State of São Paulo, using the static chamber technique and gas chromatography. The study showed high seasonal emission of methane (CH4) for the studied area, probably due to the long flooding period. It was estimated the CH4 emission factor (6.51 kg CH4 ha-1 dia-1), the partial global warming potential (pGWP, 27.2 Mg CO2eq growing season-1 ha-1) and the yield-scaled pGWP (YpGWP, 3.9 kg CO2eq kg-1 grain). ? Resumo: Estudos locais de mensuração de fluxos de gases de efeito estufa em sistemas agrícolas têm sido incentivados a nível global como base para subsidiar estimativas nacionais e estaduais de emissão. Este estudo objetivou quantificar a emissão sazonal de metano (CH4) em cultivo de arroz irrigado, sob sistema pré-germinado, no município de Tremembé, Estado de São Paulo, na safra de 2008/2009, utilizando o método de câmara estática e cromatografia gasosa. O estudo mostrou elevada emissão sazonal de CH4 para a área estudada, em função, provavelmente do longo período de inundação. Foi estimado o fator de emissão de CH4 (6,51 kg CH4 ha-1 dia-1), o potencial de aquecimento global parcial (PAGp, 27,2 Mg CO2eq estação de crescimento-1 ha-1) e o PAGp escalonado pelo rendimento (R) de grãos (PAGpR, 3,9 kg CO2eq kg-1 grão)

    COMPARISON BETWEEN ANALYTICAL PYROLYSIS AND NITROBENZENE OXIDATION FOR DETERMINATION OF SYRINGYL/GUAIACYL RATIO IN Eucalyptus spp. LIGNIN

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    Pyrolysis-gas chromatography/mass spectrometry (Py-GC-MS) was applied to measure the lignin syringyl/guaiacyl (S/G) ratio in E. dunni, E. grandis, E. nitens, E. urograndis, and E. urophylla woods. A total of 41 compounds were identified, of which 11 were derived from carbo-hydrates and 30 from lignins. The S/G ratio was calculated on the basis of the areas of peaks recorded in the pyrograms and compared with the results obtained by alkaline nitrobenzene oxidation. The values of S/G found by pyrolysis were similar for all the species using the compounds guaiacol, 4-methylguaiacol, 4-vinylguaiacol, vanillin, 4-ethylsyringol, 4-vinylsyringol, homosyringaldehyde, acetosyringone, and syringylacetone, as lignin markers. The selected markers were efficient for the deter-mination of S/G ratio in eucalyptus wood by Py-GC-MS. The Py-GC-MS technique produced results that are comparable to the nitrobenzene oxidation method, with the advantage of requiring small wood samples and a short analysis time
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