POISSON project - I - Emission lines as accretion tracers in young stellar objects: results from observations of Chamaeleon I and II sources

We present the results of the analysis of LR optical-NIR spectra (0.6-2.4 um) of a sample 47 YSOs in the ChaI and II star-forming clouds. These data are part of the POISSON project (Protostellar Optical-Infrared Spectral Survey on NTT). The aim is to determine the accretion luminosity (Lacc) and mass accretion rate (Macc) of the sources through the analysis of the detected emission features. We also aim at verifying the reliability and consistency of the existing empirical relationships connecting emission line luminosity and Lacc. We employ five tracers (OI-6300A, Ha, CaII-8542A, Pab, and Brg) to derive the accretion luminosity. The tracers provide Lacc values showing different scatters when plotted as a function of L*. The Brg seems to be the most reliable, because it gives the minimum Lacc dispersion over the entire range of L*, whereas the other tracers provide much more scattered Lacc values, which are not expected for our homogeneous sample. The comparison between Lacc(Brg) and Lacc obtained from the other tracers also shows systematic differences among the empirical relationships. These may probably be ascribed to different excitation mechanisms contributing to the line emission, which may vary between our sample and those where the relationships were calibrated. Adopting the Lacc derived from Brg, we find Lacc=0.1L*-1L* for all sources, and Macc of the order of 10^-7-10^-9 Msun/yr. The Macc derived in ChaI are proportional to M*^2, as found in other low-mass star-forming regions. The discrepancies observed in the case of Lacc(Brg) and Lacc(Pab) can be related to different intrinsic Pab/Brg, ratios. The derived ratios show the existence of two different emission modalities, one that agrees with predictions of both wind and accretion models, the other suggesting optically thick emission from relatively small regions (10^21-10^22 cm^-3) with gas at low temperatures (<4000K).Comment: 22 pages, 8 figures, accepted for publication in A&A; institute affiliations and typos correcte

Desempenho dos suínos de diferentes categorias de castração suplementados com ractopamina.

A imunocastração é uma técnica não cirúrgica e não invasiva que respeita os princípios do bem-estar animal, constituindo-se em alternativa à castração convencional de suínos machos. Já a ractopamina é um agonista &#946;-adrenérgico que vem sendo utilizado como repartidor de energia em dietas de suínos na fase de terminação com objetivos de melhorar as características da carcaça. O objetivo deste trabalho foi de estudar o efeito da interação das categorias de castração e níveis de ractopamina sobre o desempenho dos suínos nas fases de crescimento e terminação. Foram selecionados 1160 leitões machos (Camborough 25 x AGPIC 337). As castrações cirúrgicas foram realizadas em metade desses leitões no 7º dia de vida e de acordo com os procedimentos padrão de cada granja. Os demais suínos foram mantidos inteiros para serem imunocastrados na fase de crescimento e terminação, com auxilio da vacina de imunocastração. Os dados foram analisados considerando um delineamento experimental em blocos ao acaso com esquema fatorial 2x4 (duas categorias de castração x quatro níveis de ractopamina) e quatro repetições. Suínos imunocastrados apresentaram desempenho superior em relação aos castrados cirurgicamente. Immunocastration is a non-surgical and non-invasive technique that respects welfare principles and could be an alternative to conventional castration used in pigs. actopamine is a &#946;-adrenergic agonist that has been used as an energy splitter in swine diets in finishing phase to improve carcass characteristics. The main objective of this research was to study the effect of castration methods and ractopamine levels on pig performance in finishing phase. A total of 1160 male piglets (Camborough 25 x AGPIC 337) were used. Surgical castrations were performed in half of the piglets, at 7th day of life according to each farm?s procedure. The remaining piglets were kept intact to be mmunocastrated through vaccination at the finishing phase. It was used a complete randomized block design with a 2x4 factorial arrangement (two categories of castration and four levels of ractopamine) with four replications. Immunocastrated pigs showed better performance that pigs surgically castrated

Nitrogen-starvation responsive microRNAs in Coffea arabica roots: its this a 3-player game?

Nitrogen (N) is an essential macronutrient for plant growth and development. In the case of C. arabica, fertilization practices are the second major cost in coffee production. MicroRNAs (miRNAs) play key roles in regulating nitrogen metabolism in plants, but the crosstalk between N and miRNAs was mostly studied in plant models and/or herbaceous species from temperate climates

VSI: the VLTI spectro-imager

The VLTI Spectro Imager (VSI) was proposed as a second-generation instrument of the Very Large Telescope Interferometer providing the ESO community with spectrally-resolved, near-infrared images at angular resolutions down to 1.1 milliarcsecond and spectral resolutions up to R=12000. Targets as faint as K=13 will be imaged without requiring a brighter nearby reference object. The unique combination of high-dynamic-range imaging at high angular resolution and high spectral resolution enables a scientific program which serves a broad user community and at the same time provides the opportunity for breakthroughs in many areas of astrophysic including: probing the initial conditions for planet formation in the AU-scale environments of young stars; imaging convective cells and other phenomena on the surfaces of stars; mapping the chemical and physical environments of evolved stars, stellar remnants, and stellar winds; and disentangling the central regions of active galactic nuclei and supermassive black holes. VSI will provide these new capabilities using technologies which have been extensively tested in the past and VSI requires little in terms of new infrastructure on the VLTI. At the same time, VSI will be able to make maximum use of new infrastructure as it becomes available; for example, by combining 4, 6 and eventually 8 telescopes, enabling rapid imaging through the measurement of up to 28 visibilities in every wavelength channel within a few minutes. The current studies are focused on a 4-telescope version with an upgrade to a 6-telescope one. The instrument contains its own fringe tracker and tip-tilt control in order to reduce the constraints on the VLTI infrastructure and maximize the scientific return.Comment: 12 pages, to be published in Proc. SPIE conference 7013 "Optical and Infrared Interferometry", Schoeller, Danchi, and Delplancke, F. (eds.). See also http://vsi.obs.ujf-grenoble.f

The BLAST Survey of the Vela Molecular Cloud: Physical Properties of the Dense Cores in Vela-D

The Balloon-borne Large-Aperture Submillimeter Telescope (BLAST) carried out a 250, 350 and 500 micron survey of the galactic plane encompassing the Vela Molecular Ridge, with the primary goal of identifying the coldest dense cores possibly associated with the earliest stages of star formation. Here we present the results from observations of the Vela-D region, covering about 4 square degrees, in which we find 141 BLAST cores. We exploit existing data taken with the Spitzer MIPS, IRAC and SEST-SIMBA instruments to constrain their (single-temperature) spectral energy distributions, assuming a dust emissivity index beta = 2.0. This combination of data allows us to determine the temperature, luminosity and mass of each BLAST core, and also enables us to separate starless from proto-stellar sources. We also analyze the effects that the uncertainties on the derived physical parameters of the individual sources have on the overall physical properties of starless and proto-stellar cores, and we find that there appear to be a smooth transition from the pre- to the proto-stellar phase. In particular, for proto-stellar cores we find a correlation between the MIPS24 flux, associated with the central protostar, and the temperature of the dust envelope. We also find that the core mass function of the Vela-D cores has a slope consistent with other similar (sub)millimeter surveys.Comment: Accepted for publication in the Astrophysical Journal. Data and maps are available at http://blastexperiment.info

Extreme infrared variables from UKIDSS-I. A concentration in star-forming regions

We present initial results of the first panoramic search for high-amplitude near-infrared variability in theGalactic plane.We analyse the widely separated two-epoch K-band photometry in the fifth and seventh data releases of the UKIDSS Galactic plane survey.We find 45 stars with δK > 1 mag, including two previously known OH/IR stars and a Nova. Even though the midplane is not yet included in the data set, we find the majority (66 per cent) of our sample to be within known star-forming regions (SFRs), with two large concentrations in the Serpens OB2 association (11 stars) and the Cygnus-X complex (12 stars). Sources in SFRs show spectral energy distributions that support classification as young stellar objects (YSOs). This indicates that YSOs dominate the Galactic population of high-amplitude infrared variable stars at low luminosities and therefore likely dominate the total high-amplitude population. Spectroscopic follow up of the DR5 sample shows at least four stars with clear characteristics of eruptive premain- sequence variables, two of which are deeply embedded. Our results support the recent concept of eruptive variability comprising a continuum of outburst events with different timescales and luminosities, but triggered by a similar physical mechanism involving unsteady accretion. Also, we find what appears to be one of the most variable classical Be stars. © 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society

Novel putative candidate genes associated with umbilical hernia in pigs.

Abstract: Umbilical hernia is one of the most frequent anatomical defects in pigs in which abdominal contents protrude through the umbilical ring. This condition is considered to have a multifactorial basis in which environmental, infectious and genetic factors play a role. However, a better understanding about the genetic components involved in the umbilical hernia development has not yet been achieved. Although a few studies have mapped QTL for umbilical hernia, just a few candidate genes were reported. Therefore, the aim of this study was to identify genomic regions related to the development of umbilical hernias in pigs and search for potential candidate genes. A GWAS was performed with 92 cases and 233 control crossbred pigs. Five SNPs were associated with umbilical hernia: on SSC4/SSC6/SSC13 and one with unknown position. Candidate genes TBX15 and WARS2 were identified close to the SNP on SSC4. Another two candidate genes were located near the SNP associated with umbilical hernia on SSC13 (LIPI and RBM11). Further validation of these genes should be performed to improve the knowledge about umbilical hernia development in order to improve pig welfare and production by eliminating susceptible animals through genetic selection Resumo: A hérnia umbilical é um dos defeitos anatômicos mais freqüentes em suínos nos quais o conteúdo abdominal se projeta através do anel umbilical. Considera-se que esta condição tem uma base multifatorial na qual fatores ambientais, infecciosos e genéticos desempenham um papel. Entretanto, um melhor entendimento sobre os componentes genéticos envolvidos no desenvolvimento da hérnia umbilical ainda não foi alcançado. Embora alguns estudos tenham mapeado o QTL para a hérnia umbilical, apenas alguns genes candidatos foram relatados. Portanto, o objetivo deste estudo foi identificar regiões genômicas relacionadas ao desenvolvimento de hérnias umbilicais em porcos e buscar potenciais genes candidatos. Um GWAS foi realizado com 92 casos e 233 porcos cruzados de controle. Cinco SNPs foram associados com hérnia umbilical: em SSC4 / SSC6 / SSC13 e um com posição desconhecida. Os genes candidatos TBX15 e WARS2 foram identificados próximos ao SNP em SSC4. Outros dois genes candidatos foram localizados perto do SNP associado à hérnia umbilical na SSC13 (LIPI e RBM11). A validação adicional desses genes deve ser realizada para melhorar o conhecimento sobre o desenvolvimento de hérnia umbilical, a fim de melhorar o bem-estar ea produção de suínos, eliminando os animais suscetíveis por meio da seleção genétic