1,816 research outputs found

    A framework for certification of large-scale component-based parallel computing systems in a cloud computing platform for HPC services

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    This paper addresses the verification of software components in the context of their orchestration to build cloud-based scientific applications with high performance computing requirements. In such a scenario, components are often supplied by different sources and their cooperation rely on assumptions of conformity with their published behavioral interfaces. Therefore, a faulty or ill-designed component, failing to obey to the envisaged behavioral requirements, may have dramatic consequences in practice. Certifier components, introduced in this paper, implement a verification as a service framework and are able to access the implementation of other components and verify their consistency with respect to a number of functional, safety and liveness requirements relevant to a specific application or a class of them. It is shown how certifier components can be smoothly integrated in HPC Shelf, a cloud-based platform for high performance computing in which different sorts of users can design, deploy and execute scientific applications.SmartEGOV: Harnessing EGOV for Smart Governance (Foundations, methods, Tools) / NORTE-01-0145-FEDER000037, supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (EFD

    A supercritical series analysis for the generalized contact process with diffusion

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    We study a model that generalizes the CP with diffusion. An additional transition is included in the model so that at a particular point of its phase diagram a crossover from the directed percolation to the compact directed percolation class will happen. We are particularly interested in the effect of diffusion on the properties of the crossover between the universality classes. To address this point, we develop a supercritical series expansion for the ultimate survival probability and analyse this series using d-log Pad\'e and partial differential approximants. We also obtain approximate solutions in the one- and two-site dynamical mean-field approximations. We find evidences that, at variance to what happens in mean-field approximations, the crossover exponent remains close to ϕ=2\phi=2 even for quite high diffusion rates, and therefore the critical line in the neighborhood of the multicritical point apparently does not reproduce the mean-field result (which leads to ϕ=0\phi=0) as the diffusion rate grows without bound

    On the Formation of Copper Linear Atomic Suspended Chains

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    We report high resolution transmission electron microscopy and classical molecular dynamics simulation results of mechanically stretching copper nanowires conducting to linear atomic suspended chains (LACs) formation. In contrast with some previous experimental and theoretical work in literature that stated that the formation of LACs for copper should not exist our results showed the existence of LAC for the [111], [110], and [100] crystallographic directions, being thus the sequence of most probable occurence.Comment: 4 pages, 3 figure

    The nature of dark matter and the density profile and central behavior of relaxed halos

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    We show that the two basic assumptions of the model recently proposed by Manrique and coworkers for the universal density profile of cold dark matter (CDM) halos, namely that these objects grow inside out in periods of smooth accretion and that their mass profile and its radial derivatives are all continuous functions, are both well understood in terms of the very nature of CDM. Those two assumptions allow one to derive the typical density profile of halos of a given mass from the accretion rate characteristic of the particular cosmology. This profile was shown by Manrique and coworkers to recover the results of numerical simulations. In the present paper, we investigate its behavior beyond the ranges covered by present-day N-body simulations. We find that the central asymptotic logarithmic slope depends crucially on the shape of the power spectrum of density perturbations: it is equal to a constant negative value for power-law spectra and has central cores for the standard CDM power spectrum. The predicted density profile in the CDM case is well fitted by the 3D S\'ersic profile over at least 10 decades in halo mass. The values of the S\'ersic parameters depend on the mass of the structure considered. A practical procedure is provided that allows one to infer the typical values of the best NFW or S\'ersic fitting law parameters for halos of any mass and redshift in any given standard CDM cosmology.Comment: 9 pages, 6 figures, to appear in the ApJ vol. 647, september 20, 2007. Minor changes to match the published versio

    Monitoramento da carteira de projetos de PD&I com sinalização de seu impacto e alinhamento ao PDU da Embrapa Florestas.

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    Reação de frutos de mamoeiro à inoculação com Phytophthora spp.

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    O mamoeiro (Carica papaya L.) pode ser afetado por diversas doenças, que constituem o principal fator limitante da cultura, exigindo medidas adequadas de controle, sem as quais podem ocorrer grandes danos na produção e depreciação do produto na comercialização. Dentre as doenças que incidem no mamoeiro, destaca-se a podridão das raízes e dos frutos, causada por Phytophthora palmivora, sendo esta considerada uma das principais doenças da cultura.Em paralelo aconteceram também os seguintes eventos: V Seminário de Pesquisa do Recôncavo da Bahia; V Seminário Estudantil de Pesquisa da UFRB; V Seminário da Pós-Graduação da UFRB; II Seminário Regional de Pesquisa da EBDA; 5ª Jornada Científica da Embrapa Mandioca e Fruticultura; VIII Seminário Estudantil de Pesquisa e Extensão da FAMAM; Semana de Ciência, Tecnologia e Inovação no Agronegócio; Fórum de Gestores de Iniciação Científica e Tecnológica da Bahia; II Simpósio Baiano de Defesa Agropecuária; I Semana de Educação Tutorial da UFRB

    Desinfestação de material vegetal para obtenção de colônias puras de Phytophtora palmivora.

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    O agronegócio do mamão é de suma importância para o Brasil em função de aspectos econômicos e sociais. Os estados com maior produção são a Bahia, responsável por 46% do total produzido no país, e o Espírito Santo, com volume de produção da ordem de 40%. Mesmo com a importância da cultura, a pesquisa visando resistência à podridão das raízes, uma das mais importantes doenças que afetam o mamoeiro, ainda é incipiente. Causada pelo fungo Phytophthora palmivora, essa doença está disseminada por quase todas as regiões produtoras, ocorrendo especialmente nas regiões com altas precipitações pluviométricas e solos mal drenados, com o agravante de que as cultivares plantadas não apresentam resistência. Só recentemente foram iniciados estudos epidemiológicos mais específicos sobre estratégias de controle utilizando fungicidas e a reação de diferentes genótipos à infecção por este patógeno. O fator mais importante na produção de inóculo de Phytophthora relaciona-se ao tipo de propágulo: micélio (conjunto de hifas), clamidósporos (estrutura vegetativa de sobrevivência), esporângios (estruturas reprodutivas assexuais) ou zoósporos (esporos assexuais ). Esse trabalho teve como objetivo estudar procedimentos de desinfestação de material vegetal na obtenção de culturas puras de P. palmivora

    Avaliação de sintomas de Phytophthora SSP em linhagens de mamoeiro.

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    O mamoeiro cultivado comercialmente (Carica papaya L.) insere-se na classe Dicotyledoneae, subclasse Archichlamydeae, ordem Violales, subordem Caricineae, família Caricaceae e gênero Carica (MANICA, 1982). Seu centro de origem é, muito provavelmente, o Noroeste da América do Sul - vertente oriental dos Andes, ou mais precisamente, a Bacia Amazônica Superior - onde a diversidade genética é máxima, o que caracteriza o mamoeiro como uma planta tipicamente tropical (TRINDADE, 2000)
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