529 research outputs found

    The Kuiper Belt and Other Debris Disks

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    We discuss the current knowledge of the Solar system, focusing on bodies in the outer regions, on the information they provide concerning Solar system formation, and on the possible relationships that may exist between our system and the debris disks of other stars. Beyond the domains of the Terrestrial and giant planets, the comets in the Kuiper belt and the Oort cloud preserve some of our most pristine materials. The Kuiper belt, in particular, is a collisional dust source and a scientific bridge to the dusty "debris disks" observed around many nearby main-sequence stars. Study of the Solar system provides a level of detail that we cannot discern in the distant disks while observations of the disks may help to set the Solar system in proper context.Comment: 50 pages, 25 Figures. To appear in conference proceedings book "Astrophysics in the Next Decade

    Body condition score, weight variation and reproductive performance of beef cows in rangelands from the Pantanal region

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    Objetivou-se avaliar a influência do escore de condição corporal (ECC) sobre a eficiência reprodutiva de vacas de cria nos períodos prÊ e pós-parto e a probabilidade de parição, usando o escore de condição corporal e a variação ponderal no período crítico do ciclo reprodutivo. Utilizaram-se 248 vacas multíparas mantidas em pastagens nativas distribuídas em quatro estratÊgias de suplementação: mistura mineral (controle); suplemento farelado; suplemento líquido; suplemento líquido para vacas e bezerros. As avaliaçþes de peso e ECC, na escala de 1 a 9, foram realizadas no período crítico: em agosto (período prÊ-parto, 60-90 dias antes da parição) e em janeiro (período pós-parto e reprodutivo) durante quatro anos consecutivos. Para a anålise dos anos consecutivos de reprodução, criou-se um escore de reprodução, ou seja, somou-se o número de pariçþes de cada vaca durante os quatro anos pecuårios avaliados. O escore de condição corporal nos períodos prÊ e pós-parto e a idade da vaca influenciaram o escore de reprodução. Portanto, para avaliação da probabilidade de parição, foram utilizadas todas as vacas, classificadas em paridas e vazias. Utilizando equaçþes de estimação generalizadas (EEG), foi modelada a probabilidade de as matrizes serem classificadas como paridas considerando variåveis exploratórias ao longo do tempo. Para se obter probabilidade de parição superior a 80%, as vacas devem possuir escore de aproximadamente 5,5 no período prÊ-parto. Aproximadamente 60% das vacas paridas mantiveram ou ganharam peso no período crítico do ano, o que levou a maior probabilidade de reconcepção, similar ao observado para as vacas vazias, porÊm com probabilidade menor de parição. O período prÊ-parto Ê o melhor para estimar a probabilidade de parição das vacas por meio da avaliação do escore corporal. A seleção de vacas adaptadas às condiçþes bioclimåticas do Pantanal aumenta a probabilidade de produção de um bezerro por vaca por ano. _________________________________________________________________________________ ABSTRACTThe aim of this study was to evaluate the influence of body condition score (BCS) on reproductive performance of beef cows before and after calving and to evaluate the calving probability using body condition score and weight variation during critical periods of the cow reproductive cycle. From 2001 to 2005, the body condition score was recorded in 248 multiparous cows raised in native pastures, submitted to different supplementation treatments (mineral mixture only - control; dry supplement; liquid supplement and liquid supplement for cow and calves). Weighing and body condition evaluation were made on a 1-9 point scale in August (prepartum period, 60-90 days before parturition) and January (postpartum and reproductive period). A reproduction score was created in function of the body scores in four consecutive years. Except for the treatment, the other factors (body condition score in the prepartum and postpartum periods and cow age) influenced the reproduction score. Thus, the calving probabilities were estimated for all cows. Generalized estimating equations (GEE) were used to evaluate the calving probability in function of the exploratory variables over time. Calving probability higher than 80% was obtained when cows scored 5,5 before calving. In relation to weight, the results showed that about 60% of calving cows maintained or gained weight in the postpartum period, leading to increase in the rebreeding probability. Similar situation occurred with single cows; however, the calving probability was lower. These results indicate that the calving probability using BCS is better estimated before calving. Furthermore, it indicates the presence of cows more adapted to the Pantanal climatic and feeding conditions than others

    Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

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    A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results
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