2,925 research outputs found

    Performance of the distributed central analysis in BaBar

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    The total dataset produced by the BaBar experiment at the Stanford Linear Accelerator Center (SLAC) currently comprises roughly3times1093times 10^9data events and an equal amount of simulated events, corresponding to 23 Tbytes of real data and 51 Tbytes simulated events. Since individual analyses typically select a very small fraction of all events, it would be extremely inefficient if each analysis had to process the full dataset. A first, centrally managed analysis step is therefore a common pre-selection (‘skimming’) of all data according to very loose, inclusive criteria to facilitate data access for later analysis. Usually, there are common selection criteria for several analysis. However, they may change over time, e.g., when new analyses are developed. Currently,$cal

    Аналитическое описание поверхностей зубьев эволютных передач

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    Зниження габаритів зубчастих передач є актуальною задачею сучасного машинобудування. Перспективний шлях її розв'язання – застосування еволютних передач із опукло-увігнутим контактом зубців. Отримані рівняння профілів еволютних зубців на основі методу профільних нормалей. Вони необхідні для подальших досліджень якісних показників та міцності еволютних зачеплень.Lowering of dimensions of gears is an actual task of a modern machine industry. The perspective way of its decision is application of evolute gears with the convax-concave contact. On the basis of method of type normal the equations of evolute teeth are got. They are needed for further researches of high-quality indexes and durability of evolute gearings

    Hyperextended Scalar-Tensor Gravity

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    We study a general Scalar-Tensor Theory with an arbitrary coupling funtion ω(ϕ)\omega (\phi ) but also an arbitrary dependence of the ``gravitational constant'' G(ϕ)G(\phi ) in the cases in which either one of them, or both, do not admit an analytical inverse, as in the hyperextended inflationary scenario. We present the full set of field equations and study their cosmological behavior. We show that different scalar-tensor theories can be grouped in classes with the same solution for the scalar field.Comment: latex file, To appear in Physical Review

    Avaliação da estratégia de tratamento parcial do rebanho no controle da mosca-dos-chifres.

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    A mosca-dos-chifres (MDC) destaca-se dentre os principais ectoparasitos que acometem a pecuária de corte nacional. Seu controle é realizado quase exclusivamente com produtos inseticidas, o que tem levado a sérios problemas de resíduos e resistência. Alternativas não químicas e redução do uso de inseticidas tornam-se essenciais ao controle sustentável deste parasito. O presente estudo avaliou a eficiência do tratamento parcial do rebanho como estratégia de controle da MDC. Quatro experimentos foram conduzidos, utilizando produtos de diferentes classes inseticidas: lactona macrocíclica (ivermectina), fenilpirazol (fipronil), piretróide cipermetrina) e organofosforado+piretróide (clorpirifós+cipermetrina), em formulações pour-on. Em cada experimento, 200 vacas Nelore foram distribuídas em quatro grupos, para avaliação do tratamento de 20%, 50% e 100% do rebanho, além de um grupo não tratado. Contagens periódicas da MDC foram realizadas nos dias 0, 3, 7, 14, 21 e 28 em todos os animais. A eficácia dos produtos nos grupos tratados integralmente foi superior a 90% (exceto pela cipermetrina) ao final da 1ª semana pós-tratamento, sendo de modo geral superior a dos tratados parcialmente nas duas semanas iniciais. Nos grupos tratados parcialmente, a eficácia foi geralmente maior nos grupos com maior frequência de animais tratados. Independente da classe inseticida aplicada e do percentual de animais tratados (20% ou 50%), o tratamento parcial do rebanho apresentou três características principais: a) rápida e acentuada redução das infestações em todo o rebanho, b) menores níveis de redução das infestações e c) menor período de proteção, em relação ao tratamento de todo o rebanho. Apesar da redução no uso de inseticidas e do menor custo, a viabilidade do tratamento parcial do rebanho, como estratégia de controle da MDC, se limita a situações onde um menor nível e período de eficácia sejam aceitáveis, caso contrário, tratamentos adicionais podem ser necessários, comprometendo as vantagens da estratégia. As implicações do tratamento parcial do rebanho no desenvolvimento e manejo da resistência a inseticidas devem ser avaliadas. The horn fly stands out among the main ectoparasites that affect national beef cattle. This livestock pest is controlled almost exclusively by insecticide products, which has led to serious residue and resistance issues. Non-chemical alternatives and reduction of insecticide use are essential for a sustainable control of this parasite. This study evaluated the efficiency of partial herd treatment as a strategy for controlling horn flies. Four experiments were conducted using products from different insecticide classes: macrocyclic lactone (ivermectin) phenylpyrazole (fipronil), pyrethroid (cypermethrin), and an organophosphate-pyrethroid mixture (chlorpyrifos + cypermethrin), in pour-on formulations. In each experiment, 200 Nelore cows were distributed in four groups for evaluation of the treatment of 20, 50, and 100% of the herd, besides an untreated group. Periodic fly counts were performed on days 0, 3, 7, 14, 21, and 28 in all animals. Product efficacy in the full-treated herd exceeded 90% (except for cypermethrin) at the end of the 1st week after treatment, being mostly higher than in partially treated groups in the first two weeks. In the groups partially treated, efficacy was generally higher in the groups with the largest frequency of treated animals. Regardless of the insecticide class and the percentage of treated animals (20% or 50%), the partial treatment of the herd showed three main features: a) fast and marked reduction in infestations throughout the herd, b) lower reduction of horn fly infestations, and c) shorter period of protection, when compared to the full herd treatment. Despite reduction in insecticide use and lower costs, viability of partial herd treatment as a strategy for controlling the horn fly is limited to situations where a lower level and protection period are acceptable; otherwise, the need for additional treatments tends to compromise the advantages of the strategy. The implications of partial herd treatment in the development and management of insecticide resistance should be evaluated.bitstream/item/129471/1/BP125.pd

    Multidimensional Cosmology: Spatially Homogeneous models of dimension 4+1

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    In this paper we classify all 4+1 cosmological models where the spatial hypersurfaces are connected and simply connected homogeneous Riemannian manifolds. These models come in two categories, multiply transitive and simply transitive models. There are in all five different multiply transitive models which cannot be considered as a special case of a simply transitive model. The classification of simply transitive models, relies heavily upon the classification of the four dimensional (real) Lie algebras. For the orthogonal case, we derive all the equations of motion and give some examples of exact solutions. Also the problem of how these models can be compactified in context with the Kaluza-Klein mechanism, is addressed.Comment: 24 pages, no figures; Refs added, typos corrected. To appear in CQ

    Isotropization of Bianchi-Type Cosmological Solutions in Brans-Dicke Theory

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    The cosmic, general analitic solutions of the Brans--Dicke Theory for the flat space of homogeneous and isotropic models containing perfect, barotropic, fluids are seen to belong to a wider class of solutions --which includes cosmological models with the open and the closed spaces of the Friedmann--Robertson--Walker metric, as well as solutions for models with homogeneous but anisotropic spaces corresponding to the Bianchi--Type metric clasification-- when all these solutions are expressed in terms of reduced variables. The existence of such a class lies in the fact that the scalar field, ϕ\phi, times a function of the mean scale factor or ``volume element'', a3=a1a2a3a^3 = a_1 a_2 a_3, which depends on time and on the barotropic index of the equation of state used, can be written as a function of a ``cosmic time'' reduced in terms of another function of the mean scale factor depending itself again on the barotropic index but independent of the metrics here employed. This reduction procedure permites one to analyze if explicitly given anisotropic cosmological solutions ``isotropize'' in the course of their time evolution. For if so can happen, it could be claimed that there exists a subclass of solutions that is stable under anisotropic perturbations.Comment: 15 pages, Late

    Aumento das infestações pela mosca-dos-chifres em bovinos nelore no Pantanal Sul-Mato-Grossense.

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    Após sua introdução no norte do país na década de 70, a mosca-dos-chifres (Haematobia irritans) chegou à região Centro-Oeste no início dos anos 90. No Pantanal, sua presença foi registrada pela primeira vez em 1991 (Barros, 1992), demandando conhecimento sobre sua ecologia e controle.bitstream/CPAP-2009-09/56780/1/CT80.pdfFormato eletrônico

    On the Reaction Diffusion Master Equation in the Microscopic Limit

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    Stochastic modeling of reaction-diffusion kinetics has emerged as a powerful theoretical tool in the study of biochemical reaction networks. Two frequently employed models are the particle-tracking Smoluchowski framework and the on-lattice Reaction-Diffusion Master Equation (RDME) framework. As the mesh size goes from coarse to fine, the RDME initially becomes more accurate. However, recent developments have shown that it will become increasingly inaccurate compared to the Smoluchowski model as the lattice spacing becomes very fine. In this paper we give a new, general and simple argument for why the RDME breaks down. Our analysis reveals a hard limit on the voxel size for which no local RDME can agree with the Smoluchowski model
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