14,143 research outputs found
The Mass-to-Light Ratio of Binary Galaxies
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 in the B
band for 57 pairs is found to be 28 36 depending on the orbital
parameters and the distribution of optical pairs (solar unit, km
s Mpc). The best estimate of for 30 pure spiral pairs is
found to be 12 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, does not show any tendency of increase, but
found to be almost independent of the separation of pairs beyond 100 kpc. The
constancy of beyond 100 kpc may indicate that the typical halo size of
spiral galaxies is less than 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
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 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 magnitude range. For stars with , 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.
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
Exigências térmicas para o desenvolvimento de Acanthoscelides obtectus em grãos de feijão.
O objetivo deste trabalho foi avaliar as exigências térmicas para machos e fêmeas de A. obtectus.Resumo
Exact Nonequilibrium Work Generating Function for a Small Classical System
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
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
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.
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.
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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