15,067 research outputs found

    O que é vinho de qualidade?

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    bitstream/item/123314/1/bonvivant-v14-n155-p42-dez-2013.pdfPublicado também no informativo A Vindima, v. 6, n. 57, p. 4, nov. 2013

    Linear scaling computation of the Fock matrix. IX. Parallel computation of the Coulomb matrix

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    We present parallelization of a quantum-chemical tree-code [J. Chem. Phys. {\bf 106}, 5526 (1997)] for linear scaling computation of the Coulomb matrix. Equal time partition [J. Chem. Phys. {\bf 118}, 9128 (2003)] is used to load balance computation of the Coulomb matrix. Equal time partition is a measurement based algorithm for domain decomposition that exploits small variation of the density between self-consistent-field cycles to achieve load balance. Efficiency of the equal time partition is illustrated by several tests involving both finite and periodic systems. It is found that equal time partition is able to deliver 91 -- 98 % efficiency with 128 processors in the most time consuming part of the Coulomb matrix calculation. The current parallel quantum chemical tree code is able to deliver 63 -- 81% overall efficiency on 128 processors with fine grained parallelism (less than two heavy atoms per processor).Comment: 7 pages, 6 figure

    Towards the Genealogy of Borderline Personality Disorder

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    Introdução: A perturbação borderline da personalidade surge na ausência de uma categoria para classificar pessoas que se encontravam entre o diagnóstico de neurose e psicose e tem, desde o seu nascimento, sofrido modificações na sua definição e aplicação clínica. Objectivos: Este artigo tem por objectivo traçar a genealogia da perturbação borderline da personalidade de modo a ensaiar hipóteses para o surgimento desta categoria diagnóstica. Métodos: Com base numa revisão da literatura, foi efectuada uma leitura crítica da evolução da categoria borderline na psiquiatria. Resultados: A evolução do conceito pode ser definida ao longo de três fases: desde o final do XIX ao início do século XX são usadas múltiplas terminologias e o diagnóstico é heterogéneo; de 1960 a 1980 surge o conceito de organização borderline da personalidade e a sua sistematização segundo a teoria psicanalítica; desde 1980 até à actualidade ocorre a entrada na DSM III e a homogeneização do diagnóstico sob a égide da biopsiquiatria. Os limites entre as diferentes fases do conceito são fluídos e dependem das condições socio-políticas associadas. Para o nascimento da doença em análise são ensaiadas várias hipóteses: criação de novos sujeitos-psíquicos, melhor acesso à saúde mental e identificação da doença, governamentalidade biopolítica, identificação de comportamentos anteriormente não considerados patológicos, descontinuidade social, nova expressão de sofrimento e contágio social. Conclusão: A perturbação borderline da personalidade resulta de práticas, representações, interacções sociais e modos de subjectificação, onde ocorre uma nova relação entre as ideias de corpo e identidade.info:eu-repo/semantics/publishedVersio

    Entanglement Swapping: Entangling Atoms That Never Interacted

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    In this paper we discuss four different proposals of entangling atomic states of particles which have never interacted. The experimental realization proposed makes use of the interaction of Rydberg atoms with a micromaser cavity prepared in either a coherent state or in a superposition of the zero and one field Fock states. We consider atoms in either a three-level cascade or lambda configurationComment: 17 pages and 2 figure

    Comparison of Four Space Propulsion Methods for Reducing Transfer Times of Manned Mars Mission

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    We assess the possibility of reducing the travel time of a manned mission to Mars by examining four different propulsion methods, and keeping the mass at departure under 2,500 tonnes, for a fixed architecture. We evaluated representative systems of three different state of the art technologies (chemical, nuclear thermal, and electric), and one advance technology, the "Pure Electro-Magnetic Thrust" (PEMT) concept (proposed by Rubbia). A mission architecture mostly based on the Design Reference Architecture 5.0 is assumed in order to estimate the mass budget, that influences the performance of the propulsion system. Pareto curves of the duration of the mission and time of flight versus mass of mission are drawn. We conclude that the ion engine technology, combined with the classical chemical engine, yields the shortest mission times for this architecture with the lowest mass, and that chemical propulsion alone is the best to minimise travel time. The results obtained using the PEMT suggest that it could be a more suitable solution for farther destinations than Mars.Comment: Change in title, abstract and presentation so to clarify the main results. 14 pages, 7 figures and 2 table

    Enological potential of grapes produced in different periods in a tropical region of Northeast Brazil.

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    The Lower-Middle São Francisco river Valley is a new vitivinicultural region located in northeast Brazil, between 8° and 9° S latitude. ln this region 11's possible to have two-three harvests a year, mainly due to an annual average temperature of 26.4°C, with about 567 mm of rainfall between January and April, altitude of 350 m above sea leveI and use of drip irrigation. There is';a. continuous vegetative developrnent and grapevine growth occurs throughout the whole year. Grap~ composition can vary strongly according to harvest time of the year due to different climatic conditions. Wineries harvest grapes for winemaking between May and December. The aim of t4~~ study was to compare Tempranillo grapes composition harvested in two periods: June and December 2007, to best understand the influence ofharvest date on grape quality.Resumo
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