31,414 research outputs found

    Divergência genética em população pré-selecionada de bacuri (Platonia insignis).

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    Os frutos da Amazônia têm despertado grande interesse nos últimos anos, tanto em nível nacional quanto internacional em decorrência dos seus sabores exóticos, por apresentarem altos teores de vitaminas e antioxidantes e pelo aproveitamento de suas polpas no agronegócio e na indústria farmacêutica (FERNANDES et al., 2003; FRAZON, 2004). As demandas do mercado para a polpa do bacuri são semelhantes às do açaí e do cupuaçu, em que se verifica um evidente conflito entre a oferta natural e a crescente pressão da demanda dessas fruteiras devido sua sazonalidade (MENEZES et al., 2012). Os programas de melhoramento precisam se adequar e ser direcionados para atender as especificidades das diversas regiões e assim suprir as demandas de mercado e as restrições de produção (BATISTA, 2013). Em muitas situações, principalmente naquelas voltadas para fins de melhoramento genético, têm sido comum o estudo da diversidade genética com a finalidade de identificar genitores adequados ao cruzamento tendo em vista a obtenção de híbridos de maiores efeitos heteróticos que proporcionem maior segregação em recombinações e possibilitem o aparecimento de transgressivos (CRUZ et al., 2011). O bacuri apresenta flores perfeitas de tamanho grande, assim, a emasculação e os cruzamentos controlados se darão de maneira relativamente simples entre os genitores geneticamente divergentes, para a obtenção dos híbridos (progênies) do segundo ciclo de seleção recorrente. O objetivo deste trabalho foi determinar os grupos geneticamente divergentes entre genótipos de bacuri pré-selecionados para os atributos agrotecnológicos

    Non-Gaussian two-mode squeezing and continuous variable entanglement of linearly and circularly polarized light beams interacting with cold atoms

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    We investigate how entangled coherent states and superpositions of low intensity coherent states of non-Gaussian nature can be generated via non-resonant interaction between either two linearly or circularly polarized field modes and an ensemble of X-like four-level atoms placed in an optical cavity. We compare our results to recent experimental observations and argue that the non-Gaussian structure of the field states may be present in those systems.Comment: 10 pages, 7 figures, replaced with final published versio

    Ising Ferromagnet: Zero-Temperature Dynamic Evolution

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    The dynamic evolution at zero temperature of a uniform Ising ferromagnet on a square lattice is followed by Monte Carlo computer simulations. The system always eventually reaches a final, absorbing state, which sometimes coincides with a ground state (all spins parallel), and sometimes does not (parallel stripes of spins up and down). We initiate here the numerical study of ``Chaotic Time Dependence'' (CTD) by seeing how much information about the final state is predictable from the randomly generated quenched initial state. CTD was originally proposed to explain how nonequilibrium spin glasses could manifest equilibrium pure state structure, but in simpler systems such as homogeneous ferromagnets it is closely related to long-term predictability and our results suggest that CTD might indeed occur in the infinite volume limit.Comment: 14 pages, Latex with 8 EPS figure

    Automatic allocation of safety requirements to components of a software product line

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    Safety critical systems developed as part of a product line must still comply with safety standards. Standards use the concept of Safety Integrity Levels (SILs) to drive the assignment of system safety requirements to components of a system under design. However, for a Software Product Line (SPL), the safety requirements that need to be allocated to a component may vary in different products. Variation in design can indeed change the possible hazards incurred in each product, their causes, and can alter the safety requirements placed on individual components in different SPL products. Establishing common SILs for components of a large scale SPL by considering all possible usage scenarios, is desirable for economies of scale, but it also poses challenges to the safety engineering process. In this paper, we propose a method for automatic allocation of SILs to components of a product line. The approach is applied to a Hybrid Braking System SPL design

    A flat faint end of the Fornax cluster galaxy luminosity function

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    We analyse the photometric properties of the early-type Fornax cluster dwarf galaxy population (M_V>-17 mag), based on a wide field imaging study of the central cluster area in V and I band-passes with IMACS/Magellan at Las Campanas Observatory. We create a fiducial sample of ~100 Fornax cluster dwarf ellipticals (dEs) with -16.6<M_V<-8.8 mag in the following three steps: (1) To verify cluster membership, we measured I-band surface brightness fluctuations (SBF) distances to candidate dEs known from previous surveys; (2) We re-assessed morphological classifications for those candidate dEs that are too faint for SBF detection; and (3) We searched for new candidate dEs in the size-luminosity regime close to the resolution limit of previous surveys. The resulting fiducial dE sample follows a well-defined surface brightness - magnitude relation, showing that Fornax dEs are about 40% larger than Local Group dEs. The sample also defines a colour-magnitude relation similar to that of Local Group dEs. The early-type dwarf galaxy luminosity function in Fornax has a very flat faint end slope alpha = -1.1 +/- 0.1. We compare the number of dwarfs per unit mass with those in other environments and find that the Fornax cluster fits well into a general trend of a lack of high-mass dwarfs in more massive environments.Comment: 5 pages, 4 figures, to appear in the proceedings of IAU Symposium 244 'Dark galaxies and lost baryons', Cambridge University Press, editors J. I. Davies & M. D. Disne

    Multimode Hong-Ou-Mandel interference

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    We consider multimode two-photon interference at a beam splitter by photons created by spontaneous parametric down-conversion. The resulting interference pattern is shown to depend upon the transverse spatial symmetry of the pump beam. In an experiment, we employ the first-order Hermite-Gaussian modes in order to show that, by manipulating the pump beam, one can control the resulting two-photon interference behavior. We expect these results to play an important role in the engineering of quantum states of light for use in quantum information processing and quantum imaging.Comment: 4 pages, 6 figures, submitted to PR

    A Terminologia aplicada ao projeto INTAGRO nas perspectivas da organização e difusão da informação e da representação do conhecimento.

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    No contexto da agropecuária brasileira, o projeto Intagro (Intensificação Agropecuária em Pólos de Produção de Soja e Cana de Açúcar: Territorialidade, Sustentabilidade e Competitividade), desenvolvido pela Embrapa Informática Agropecuária, trata de questões referentes ao processo de intensificação agropecuária e suas relações com territorialidade, sustentabilidade e competitividade. Para esse fim, o projeto inclui estudos de diferentes abordagens que englobam aspectos agroambientais e socioeconômicos, bem como aqueles relacionados à disseminação e organização da informação, e à representação do conhecimento desse domínio. Nesse último aspecto, vêm sendo desenvolvidas atividades de cunho terminológico para subsidiar o processo de integração e apropriação dos conhecimentos gerados, variando desde a extração semiautomática até a definição do repertório de termos. Este trabalho apresenta a tarefa de descrição terminológica do conjunto dos termos, coletados no escopo desse projeto para servir de recurso terminológico complementar em diferentes iniciativas do setor agropecuário brasileiro
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