3,567 research outputs found

    The Quest for Light Sea Quarks: Algorithms for the Future

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    As part of a systematic algorithm study, we present first results on a performance comparison between a multibosonic algorithm and the hybrid Monte Carlo algorithm as employed by the SESAM collaboration. The standard Wilson fermion action is used on 32*16^3 lattices at beta=5.5.Comment: LaTeX, 3 pages, Lattice2001(algorithms

    Simultaneous learning of instantaneous and time-delayed genetic interactions using novel information theoretic scoring technique

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    BACKGROUND: Understanding gene interactions is a fundamental question in systems biology. Currently, modeling of gene regulations using the Bayesian Network (BN) formalism assumes that genes interact either instantaneously or with a certain amount of time delay. However in reality, biological regulations, both instantaneous and time-delayed, occur simultaneously. A framework that can detect and model both these two types of interactions simultaneously would represent gene regulatory networks more accurately. RESULTS: In this paper, we introduce a framework based on the Bayesian Network (BN) formalism that can represent both instantaneous and time-delayed interactions between genes simultaneously. A novel scoring metric having firm mathematical underpinnings is also proposed that, unlike other recent methods, can score both interactions concurrently and takes into account the reality that multiple regulators can regulate a gene jointly, rather than in an isolated pair-wise manner. Further, a gene regulatory network (GRN) inference method employing an evolutionary search that makes use of the framework and the scoring metric is also presented. CONCLUSION: By taking into consideration the biological fact that both instantaneous and time-delayed regulations can occur among genes, our approach models gene interactions with greater accuracy. The proposed framework is efficient and can be used to infer gene networks having multiple orders of instantaneous and time-delayed regulations simultaneously. Experiments are carried out using three different synthetic networks (with three different mechanisms for generating synthetic data) as well as real life networks of Saccharomyces cerevisiae, E. coli and cyanobacteria gene expression data. The results show the effectiveness of our approach

    Comparação de métodos convencional e alternativo para determinar Cu, Fe, Mn E Zn em extratos de solos obtidos com solução de Mehlich-1.

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    Nos laboratórios brasileiros, a determinação de micronutrientes para estudos de fertilidade de solos é realizada por extração com solução de Mehlich-1 (M-1), utilizando-se uma razão solo: extrator de 1:5 m/v e posterior quantificação por espectrometria de absorção atômica (AAS). No entanto, muitos laboratórios também empregam razão solo:extrator M-1 de 1:10 m/v para determinar macronutrientes e, ou, quantificar por espectrometria de emissão óptica com plasma indutivamente acoplado (ICP OES), em substituição ao AAS. Como estudos comparativos entre as concentrações de micronutrientes obtidos por esses métodos alternativos são escassos, o objetivo deste trabalho foi investigar se essas diferentes condições experimentais gerariam diferentes resultados. Os resultados foram estatisticamente tratados e revelaram que as concentrações de Fe e Mn, utilizando se ambas as razões de solo:extrator M-1 (1:5 e 1:10 m/v) e de Zn, na razão solo: extrator M-1 de 1:10 m/v, foram estatisticamente iguais, enquanto as concentrações de Cu em ambas as razões solo:extrator M-1 e de Zn na razão solo:extrator de 1:5 m/v foram diferentes, quando as duas técnicas de quantificação (ICP OES e AAS) foram comparadas. Também, todas as concentrações de Cu, Fe, Mn e Zn obtidas utilizando razão solo: extrator M-1 de 1:5 m/v foram diferentes daquelas encontradas com a razão de 1:10 m/v, independentemente da técnica de quantificação. A maioria dessas concentrações foi maior quando se usou a razão de 1:5 m/v e alterou a classe de interpretação dos teores. Portanto, não recomenda-se o uso da razão solo: extrator de 1:5 para as extrações dos micronutrientes Cu, Fe, Mn e Zn com solução M-1 de amostras de solo

    Comparação de métodos convencional e alternativo para determinar Cu, Fe, Mn e Zn em extratos de solos obtidos com solução de MEHLICH-1.

    Get PDF
    Nos laboratórios brasileiros, a determinação de micronutrientes para estudos de fertilidade de solos é realizada por extração com solução de Mehlich-1 (M-1), utilizando-se uma razão solo: extrator de 1:5 m/v e posterior quantificação por espectrometria de absorção atômica (AAS). No entanto, muitos laboratórios também empregam razão solo:extrator M-1 de 1:10 m/v para determinar macronutrientes e, ou, quantificar por espectrometria de emissão óptica com plasma indutivamente acoplado (ICP OES), em substituição ao AAS. Como estudos comparativos entre as concentrações de micronutrientes obtidos por esses métodos alternativos são escassos, o objetivo deste trabalho foi investigar se essas diferentes condições experimentais gerariam diferentes resultados. Os resultados foram estatisticamente tratados e revelaram que as concentrações de Fe e Mn, utilizandose ambas as razões de solo:extrator M-1 (1:5 e 1:10 m/v) e de Zn, na razão solo:extrator M-1 de 1:10 m/v, foram estatisticamente iguais, enquanto as concentrações de Cu em ambas as razões solo:extrator M-1 e de Zn na razão solo:extrator de 1:5 m/v foram diferentes, quando as duas técnicas de quantificação (ICP OES e AAS) foram comparadas. Também, todas as concentrações de Cu, Fe, Mn e Zn obtidas utilizando razão solo:extrator M-1 de 1:5 m/v foram diferentes daquelas encontradas com a razão de 1:10 m/v, independentemente da técnica de quantificação. A maioria dessas concentrações foi maior quando se usou a razão de 1:5 m/v e alterou a classe de interpretação dos teores. Portanto, não recomenda-se o uso da razão solo:extrator de 1:5 para as extrações dos micronutrientes Cu, Fe, Mn e Zn com solução M-1 de amostras de solo

    Genetic diversity analysis among pigeonpea genotypes adapted to South American regions based on microsatellite markers.

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    The pigeonpea [Cajanus cajan (L) Millspaugh] is one of the most important perennial legume crops utilized in the food, fodder, soil conservation, crop-livestock integrated systems, reclaiming of degraded pastures and symbiotic nitrogen fixation. Microsatellite markers were used to estimate the genetic diversity of 77 pigeonpea genotypes selected from the germplasm collections at Embrapa Cattle-Southeast and, to evaluate their transferability to Phaseolus vulgaris and Vigna unguiculata species. The number of alleles per locus ranged from 2 to12, with an average of 5.1 alleles. The PIC values ranged from 0.11 to 0.80 (average 0.49) and the D values from 0.23 to 0.91 (average 0.58). The averages of observed and expected heterozygosity were 0.25 and 0.47, respectively, showing a deficit in heterozygosity. A model-based Bayesian approach implemented in the software STRUCTURE was used to assign genotypes into clusters. A dendrogram was constructed based on the modified Roger's genetic distances using a neighbor-joining method (NJ). A total of four clusters were assembled by STRUCTURE and a strong tendency of correspondence between the Bayesian clusters in the NJ tree was observed. The genetic distance ranged from 0.09 to 0.62 (average 0.37), showing a low genetic diversity in the pigeonpea genotypes. Transferability of pigeonpea-specific microsatellites revealed a cross-amplification and the presence of polymorphic alleles in P. vulgaris and V. unguiculata

    Immature hard ticks infected with Rickettsia amblyommatis on breeding birds from Pantanal

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    Immature hard ticks from the genus Amblyomma feed on blood from a wide range of Neotropical avian hosts. They serve as vectors for pathogens of medical and veterinary importance, such as Rickettsia agents of the spotted fever group (SFG). Hence, determining ecological factors that increase encounter rates between immature ticks and their avian hosts may contribute to the understanding of tick-borne diseases transmission. Here, we used 720 individual birds from 96 species surveyed in the Brazilian Pantanal to test whether host breeding season influenced tick infestation probabilities. Additionally, collected ticks were screened for Rickettsia agents to describe new avian-tick-bacteria associations. Our models revealed that the probability of an individual bird being infested with immature ticks was similar during the breeding and pre-breeding season, but higher loads of immature tick stages were found during the breeding season. Host sex did not predict infestation probability, but Rickettsia agents recovered from ticks were more prevalent during the pre-breeding season. The new records of host usage by larvae and nymphs of Amblyomma in Pantanal and the growing body of tick surveys in Neotropical avian communities, suggest that immature ticks may benefit from avian blood sources during their annual cycle. The low number of infected ticks with Rickettsia agents on Pantanal birds suggest that this vertebrate group are likely not acting as reservoirs for these microorganisms. However, long-term surveys at the same site are imperative to determine which tick species are acting as reservoirs for Rickettsia agents in Pantanal and determine whether birds are playing a role in dispersing ticks and tick-borne pathogens.Fil: Fecchio, Alan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Centro de Investigación Esquel de Montaña y Estepa Patagónica. Universidad Nacional de la Patagonia "San Juan Bosco". Centro de Investigación Esquel de Montaña y Estepa Patagónica; Argentina. Universidade Federal Do Mato Grosso (ufmt);Fil: Martins, Thiago Fernandes. Universidade de Sao Paulo; Brasil. Secretaria de Estado Da Saude de Sao Paulo; BrasilFil: Dias, Raphael I.. Universidade do Brasília; BrasilFil: Bell, Jeffrey A.. University Of North Dakota; Estados UnidosFil: Pinho, João B.. Universidade Federal Do Mato Grosso (ufmt);Fil: Silva, Victoria Luiza de Barros. Universidade Federal Do Mato Grosso (ufmt);Fil: Pacheco, Richard de Campos. Universidade Federal Do Mato Grosso (ufmt)
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