14,143 research outputs found

    The Mass-to-Light Ratio of Binary Galaxies

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    We report on the mass-to-light ratio determination based on a newly selected binary galaxy sample, which includes a large number of pairs whose separations exceed a few hundred kpc. The probability distributions of the projected separation and the velocity difference have been calculated considering the contamination of optical pairs, and the mass-to-light ratio has been determined based on the maximum likelihood method. The best estimate of M/LM/L in the B band for 57 pairs is found to be 28 \sim 36 depending on the orbital parameters and the distribution of optical pairs (solar unit, H0=50H_0=50 km s1^{-1} Mpc1^{-1}). The best estimate of M/LM/L for 30 pure spiral pairs is found to be 12 \sim 16. These results are relatively smaller than those obtained in previous studies, but consistent with each other within the errors. Although the number of pairs with large separation is significantly increased compared to previous samples, M/LM/L does not show any tendency of increase, but found to be almost independent of the separation of pairs beyond 100 kpc. The constancy of M/LM/L beyond 100 kpc may indicate that the typical halo size of spiral galaxies is less than 100\sim 100 kpc.Comment: 18 pages + 8 figures, to appear in ApJ Vol. 516 (May 10

    Image Subtraction Reduction of Open Clusters M35 & NGC 2158 In The K2 Campaign-0 Super-Stamp

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    Observations were made of the open clusters M35 and NGC 2158 during the initial K2 campaign (C0). Reducing these data to high-precision photometric time-series is challenging due to the wide point spread function (PSF) and the blending of stellar light in such dense regions. We developed an image-subtraction-based K2 reduction pipeline that is applicable to both crowded and sparse stellar fields. We applied our pipeline to the data-rich C0 K2 super-stamp, containing the two open clusters, as well as to the neighboring postage stamps. In this paper, we present our image subtraction reduction pipeline and demonstrate that this technique achieves ultra-high photometric precision for sources in the C0 super-stamp. We extract the raw light curves of 3960 stars taken from the UCAC4 and EPIC catalogs and de-trend them for systematic effects. We compare our photometric results with the prior reductions published in the literature. For detrended, TFA-corrected sources in the 12--12.25 Kp\rm K_{p} magnitude range, we achieve a best 6.5 hour window running rms of 35 ppm falling to 100 ppm for fainter stars in the 14--14.25 Kp \rm K_{p} magnitude range. For stars with Kp>14\rm K_{p}> 14, our detrended and 6.5 hour binned light curves achieve the highest photometric precision. Moreover, all our TFA-corrected sources have higher precision on all time scales investigated. This work represents the first published image subtraction analysis of a K2 super-stamp. This method will be particularly useful for analyzing the Galactic bulge observations carried out during K2 campaign 9. The raw light curves and the final results of our detrending processes are publicly available at \url{http://k2.hatsurveys.org/archive/}.Comment: Accepted for publication in PASP. 14 pages, 5 figures, 2 tables. Light curves available from http://k2.hatsurveys.org/archive

    Sistema de produção de leite em Rondônia: produção, reprodução, nutrição e alimentação.

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    Esta publicação apresenta um estudo sobre a produção leiteira no Estado de RO e propõe ações otimizadoras da produção.bitstream/item/24795/1/rt91-sistemadeproducaodeleite.pd

    Exact Nonequilibrium Work Generating Function for a Small Classical System

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    We obtain the exact nonequilibrium work generating function (NEWGF), for a small system consisting of a massive Brownian particle connected to internal and external springs. The external work is provided to the system for a finite time interval. The Jarzynski equality (JE), obtained in this case directly from the NEWGF, is shown to be valid for the present model, in an exact way regardless of the rate of external work

    Groove Pancreatitis with Biliary and Duodenal Stricture: An Unusual Cause of Obstructive Jaundice

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    INTRODUCTION: Groove pancreatitis is an uncommon cause of chronic pancreatitis that affects the groove anatomical area between the head of the pancreas, duodenum, and common bile duct. CLINICAL CASE: A 67-year-old man with frequent biliary colic and an alcohol consumption of 30-40 g/day was admitted to the hospital complaining of jaundice and pruritus. Laboratory analysis revealed cholestasis and the ultrasound scan showed intra-hepatic biliary ducts dilatation, middle third cystic dilatation of common bile duct, enlarged Wirsung and pancreatic atrophy. The magnetic resonance cholangiopancreatography showed imaging findings compatible with groove pancreatitis. An esophagogastroduodenoscopy later excluded duodenal neoplasia. He was submitted to a Roux-en-Y cholangiojejunostomy because of common bile duct stricture. Five months later a gastrojejunostomy was performed due to a duodenal stricture. The patient remains asymptomatic during follow-up. DISCUSSION: Groove pancreatitis is a benign cause of obstructive jaundice, whose main differential diagnosis is duodenal or pancreatic neoplasia. When this condition causes duodenal or biliary stricture, surgical treatment can be necessary.info:eu-repo/semantics/publishedVersio

    Observation of environment-induced double sudden transitions in geometric quantum correlations

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    Correlations in quantum systems exhibit a rich phenomenology under the effect of various sources of noise. We investigate theoretically and experimentally the dynamics of quantum correlations and their classical counterparts in two nuclear magnetic resonance setups, as measured by geometric quantifiers based on trace-norm. We consider two-qubit systems prepared in Bell diagonal states, and perform the experiments in decohering environments resulting from Bell diagonal-preserving Markovian local noise. We then report the first observation of environment-induced double sudden transitions in the geometric quantum correlations, a genuinely nonclassical effect not observable in classical correlations. The evolution of classical correlations in our physical implementation reveals in turn the finite-time relaxation to a pointer basis under nondissipative decoherence, which we characterize geometrically in full analogy with predictions based on entropic measures.Comment: 5 pages, 2 figures. v2: Minor corrections. Published versio

    Metodologias para avaliação de alimentos para ruminantes domésticos.

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    Esta publicação consiste em uma revisão bibliográfica que tem por objetivo reunir as principais metodologias de avaliação nutricional de alimentos para ruminantes domésticos enfatizando seus princípios e suas limitações, para que as mesmas sejam utilizadas de maneira mais consciente por estudantes e técnicos de laboratório.bitstream/item/45987/1/doc136-alimentacaoderuminantes.pd

    Métodos de amostragem para avaliação quantitativa de pastagens.

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    O objetivo deste trabalho foi levantar as principais técnicas utilizadas para coleta de amostras para determinação de forragem disponível na pastagem, considerando-se as vantagens e desvantagens de cada uma, visando fornecer subsídios para a tomada de decisão na hora de escolher o método mais adequado para cada situação.bitstream/item/24669/1/ct84-pastagem.pd
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