187 research outputs found

    Neutrinos in Non-linear Structure Formation - The Effect on Halo Properties

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    We use N-body simulations to find the effect of neutrino masses on halo properties, and investigate how the density profiles of both the neutrino and the dark matter components change as a function of the neutrino mass. We compare our neutrino density profiles with results from the N-one-body method and find good agreement. We also show and explain why the Tremaine-Gunn bound for the neutrinos is not saturated. Finally we study how the halo mass function changes as a function of the neutrino mass and compare our results with the Sheth-Tormen semi-analytic formulae. Our results are important for surveys which aim at probing cosmological parameters using clusters, as well as future experiments aiming at measuring the cosmic neutrino background directly.Comment: 20 pages, 8 figure

    Mushy Zone Morphology During Directional Solidification of Pb-5.8 Wt Pct Sb Alloy

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    The Pb-5.8 wt pet Sb alloy was directionally solidified with a positive thermal gradient of 140 K cm(-1) at a growth speed ranging from 0.8 to 30 mu m s(-1), and then it was quenched to retain the mushy zone morphology. The morphology of the mushy zone along its entire length has been characterized by using a serial sectioning and three-dimensional image reconstruction technique. Variation in the cellular/dendritic shape factor, hydraulic radius of the interdendritic region, and fraction solid along the mushy zone length has been studied. A comparison with predictions from theoretical models indicates that convection remarkably reduces the primary dendrite spacing while its influence on the dendrite tip radius is not as significant

    The genome of the stable fly, Stomoxys calcitrans, reveals potential mechanisms underlying reproduction, host interactions, and novel targets for pest control.

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    The stable fly, Stomoxys calcitrans, is a major blood-feeding pest of livestock that has near worldwide distribution, causing an annual cost of over $2 billion for control and product loss in the USA alone. Control of these flies has been limited to increased sanitary management practices and insecticide application for suppressing larval stages. Few genetic and molecular resources are available to help in developing novel methods for controlling stable flies. This study examines stable fly biology by utilizing a combination of high-quality genome sequencing and RNA-Seq analyses targeting multiple developmental stages and tissues. In conjunction, 1600 genes were manually curated to characterize genetic features related to stable fly reproduction, vector host interactions, host-microbe dynamics, and putative targets for control. Most notable was characterization of genes associated with reproduction and identification of expanded gene families with functional associations to vision, chemosensation, immunity, and metabolic detoxification pathways. The combined sequencing, assembly, and curation of the male stable fly genome followed by RNA-Seq and downstream analyses provide insights necessary to understand the biology of this important pest. These resources and new data will provide the groundwork for expanding the tools available to control stable fly infestations. The close relationship of Stomoxys to other blood-feeding (horn flies and Glossina) and non-blood-feeding flies (house flies, medflies, Drosophila) will facilitate understanding of the evolutionary processes associated with development of blood feeding among the Cyclorrhapha

    Metodologias de avaliação do valor nutricional do farelo de arroz desengordurado para suínos

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    O objetivo deste trabalho foi comparar o método de substituição com o de análise de regressão, na determinação do valor nutricional do farelo de arroz desengordurado, em dietas para suínos, nas fases de crescimento e terminação. Foram conduzidos dois ensaios de digestibilidade com 16 suínos machos castrados na fase de crescimento, com peso vivo inicial de 50,0±3,1 kg, e 16 suínos machos castrados na fase de terminação, com peso vivo inicial de 95,0±3,8 kg, alojados em gaiolas metabólicas. Utilizou-se o delineamento inteiramente casualizado com quatro tratamentos − 0, 15, 30 e 45% de substituição da dieta‑referência por farelo de arroz desengordurado − e quatro repetições, com um animal como unidade experimental. A análise de regressão foi mais precisa para estimar o valor nutricional do farelo de arroz desengordurado do que o método de substituição. Por esta análise, os coeficientes de digestibilidade aparente da matéria seca, matéria orgânica, proteína bruta e o valor de energia metabolizável do farelo de arroz desengordurado foram, respectivamente: 57,7, 64,8, 56,6% e 2.429 kcal kg‑1, na fase de crescimento, e 57,7, 64,7, 62,6% e 2.233 kcal kg‑1, na fase de terminação.The objective of this work was to compare the substitution method and the regression analysis method to determine the nutritional value of defatted rice bran in diets for swines at growing and finishing phases. Two digestibility bioassays were carried out with 16 barrows with initial body weight of 50.0±3.1 kg, in the growing phase, and 16 barrows with initial body weight of 95.0±3.8 kg, in the finishing phase, housed in metabolic cages. A completely randomized design was used with four treatments − 0, 15, 30 and 45% of substitution of the reference diet by defatted rice bran − and four replications, with one animal as the experimental unit. The regression analysis was more accurate than the method of substitution to assess the nutritional value of defatted rice bran. Throught this analyse, the apparent digestibility coefficients of dry matter, organic matter, crude protein and metabolizable energy of defatted rice bran were, respectively, 57.7, 64.8, 56.6% and 2,429 kcal kg‑1 on growing phase, and 57.7, 64.7, 62.6% and 2,233 kcal kg‑1 on finishing phase
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