Numerical simulations challenged on the prediction of massive subhalo abundance in galaxy clusters: the case of Abell 2142

In this Letter we compare the abundance of member galaxies of a rich, nearby ($z=0.09$) galaxy cluster, Abell 2142, with that of halos of comparable virial mass extracted from sets of state-of-the-art numerical simulations, both collisionless at different resolutions and with the inclusion of baryonic physics in the form of cooling, star formation, and feedback by active galactic nuclei. We also use two semi-analytical models to account for the presence of orphan galaxies. The photometric and spectroscopic information, taken from the Sloan Digital Sky Survey Data Release 12 (SDSS DR12) database, allows us to estimate the stellar velocity dispersion of member galaxies of Abell 2142. This quantity is used as proxy for the total mass of secure cluster members and is properly compared with that of subhalos in simulations. We find that simulated halos have a statistically significant ($\gtrsim 7$ sigma confidence level) smaller amount of massive (circular velocity above $200\,{\rm km\, s^{-1}}$) subhalos, even before accounting for the possible incompleteness of observations. These results corroborate the findings from a recent strong lensing study of the Hubble Frontier Fields galaxy cluster MACS J0416 \citep{grillo2015} and suggest that the observed difference is already present at the level of dark matter (DM) subhalos and is not solved by introducing baryonic physics. A deeper understanding of this discrepancy between observations and simulations will provide valuable insights into the impact of the physical properties of DM particles and the effect of baryons on the formation and evolution of cosmological structures.Comment: 8 pages, 2 figures. Modified to match the version published in ApJ

GAIA: Composition, Formation and Evolution of the Galaxy

The GAIA astrometric mission has recently been approved as one of the next two `cornerstones' of ESA's science programme, with a launch date target of not later than mid-2012. GAIA will provide positional and radial velocity measurements with the accuracies needed to produce a stereoscopic and kinematic census of about one billion stars throughout our Galaxy (and into the Local Group), amounting to about 1 per cent of the Galactic stellar population. GAIA's main scientific goal is to clarify the origin and history of our Galaxy, from a quantitative census of the stellar populations. It will advance questions such as when the stars in our Galaxy formed, when and how it was assembled, and its distribution of dark matter. The survey aims for completeness to V=20 mag, with accuracies of about 10 microarcsec at 15 mag. Combined with astrophysical information for each star, provided by on-board multi-colour photometry and (limited) spectroscopy, these data will have the precision necessary to quantify the early formation, and subsequent dynamical, chemical and star formation evolution of our Galaxy. Additional products include detection and orbital classification of tens of thousands of extra-Solar planetary systems, and a comprehensive survey of some 10^5-10^6 minor bodies in our Solar System, through galaxies in the nearby Universe, to some 500,000 distant quasars. It will provide a number of stringent new tests of general relativity and cosmology. The complete satellite system was evaluated as part of a detailed technology study, including a detailed payload design, corresponding accuracy assesments, and results from a prototype data reduction development.Comment: Accepted by A&A: 25 pages, 8 figure

Helicobacter pylori Dampens HLA-II Expression on Macrophages via the Up-Regulation of miRNAs Targeting CIITA

Macrophages have a major role in infectious and inflammatory diseases, and the available data suggest that Helicobacter pylori persistence can be explained in part by the failure of the bacterium to be killed by professional phagocytes. Macrophages are cells ready to kill the engulfed pathogen, through oxygen-dependent and -independent mechanisms; however, their killing potential can be further augmented by the intervention of T helper (Th) cells upon the specific recognition of human leukocyte antigen (HLA)-II\u2013peptide complexes on the surface of the phagocytic cells. As it pertains to H. pylori, the bacterium is engulfed by macrophages, but it interferes with the phagosome maturation process leading to phagosomes with an altered degradative capacity, and to megasomes, wherein H. pylori resists killing. We recently showed that macrophages infected with H. pylori strongly reduce the expression of HLA-II molecules on the plasma membrane and this compromises the bacterial antigen presentation to Th lymphocytes. In this work, we demonstrate that H. pylori hampers HLA-II expression in macrophages, activated or non-activated by IFN-\u3b3, by down-regulating the expression of the class II major histocompatibility complex transactivator (CIITA), the \u201cmaster control factor\u201d for the expression of HLA class II genes. We provided evidence that this effect relies on the up-regulation of let-7f-5p, let-7i-5p, miR-146b-5p, and -185-5p targeting CIITA. MiRNA expression analysis performed on biopsies from H. pylori-infected patients confirmed the up-regulation of let-7i-5p, miR-146b-5p, and -185-5p in gastritis, in pre-invasive lesions, and in gastric cancer. Taken together, our results suggest that specific miRNAs may be directly involved in the H. pylori infection persistence and may contribute to confer the risk of developing gastric neoplasia in infected patients

Estimativas de componentes de variância e herdabilidade para características reprodutivas e de crescimento em bovinos da raça Canchim.

Estudou-se neste trabalho dados referentes às características de idade ao primeiro parto (lPP), idade ao segundo parto (ISP), perímetro escrotal aos 420 dias de idade (PE420) e peso aos 420 dias de idade de machos e fêmeas (P420) de animais da raça Canchim, para as quais foram obtidas estimativas de herdabilidade. No modelo animal, foram incluídos os efeitos fixos de grupo de contemporâneos e os efeitos aleatórios aditivos diretos e residuais. Empregou-se o método da máxima verossimilhança restrita em análise uni-característica. As médias observadas de IPP, ISP, PE420 e P420 foram iguais a 39,47±7,20 meses, 57,08±8,79 meses, 24,63±3,84 cm e 260,37±46,5l kg, respectivamente. As herdabilidades foram iguais a 0,03±0,Ol, 0,07±0,Ol, 0,22±0,05 e 0,24±0,03 para IPP, ISP, PE420 e P420, respectivamente. Dentre as características reprodutivas e de crescimento estudadas o perímetro escrotal e o peso aos 420 dias de idade apresentaram estimativas de herdabilidade de moderada magnitude, indicando que a seleção para estas características poderá contribuir para o melhoramento genético da raça Canchim

Estimativas de parâmetros genéticos para características reprodutivas e de crescimento em bovinos Canchim por método Bayesiano.

Obtiveram-se, neste estudo, parâmetros genéticos para as caracteristicas de permanência de remeas no rebanho aos 76 meses de idade (PR76), idade ao primeiro parto (IPP), perímetro escrotal aos 420 dias de idade (PE420) e peso aos 420 dias de idade de machos e fêmeas (P420) de animais da raça Canchim. No modelo animal, foram incluídos o grupo de contemporâneos e os efeitos aleatórios aditivos diretos e residuais. Os dados foram analisados por meio de inferência Bayesiana, em análise uni¬característica. As médias de PR76, IPP, PE420 e P420 foram iguais a 1,57±0,73 bezerros, 39,47±7,20 meses, 24,63±3,84 cm e 260,37±46,5l kg, respectivamente. As herdabilidades foram iguais a 0,0299±0,008, 0,0236±0,009, 0,2357±0,060 e 0,2235±0,048 para PR76, IPP, PE420 e P420, respectivamente. As estimativas de herdabilidade para PE420 e P420 indicam que a seleção direta para estas características pode resultar em progresso genético do rebanho da raça Canchim. As estimativas para as características reprodutivas PR76 e IPP indicam que a seleção destas pouco contribuirá para o melhoramento genético da raça

Estimativas de parâmetros genéticos para características reprodutivas e de crescimento em bovinos da raça Canchim.

Estudou-se neste trabalho dados referentes às características de idade ao segundo parto (ISP), perímetro escrotal aos 420 dias de idade (PE420) e peso aos 420 dias de idade de machos e fêmeas (P420) de animais da raça Canchim, para as quais foram obtidas estimativas de herdabilidade e correlações genéticas. No modelo animal, foram incluídos os efeitos fixos de grupo de contemporâneos e os efeitos aleatórios aditivos diretos e residuais. Utilizou-se o método da máxima verossimilhança restrita em análise bi-característica. As médias de ISP, PE420 e P420 foram iguais a 57,07±8,69 meses, 24,63±3,84 cm e 260,37±46,5l kg, respectivamente. As estimativas de herdabilidade foram 0,07±0,01, 0,2l±0,05 e 0,24±0,03, respectivamente para ISP, PE420 e P420. As correlações genéticas foram iguais a -0,47 (ISPXPE420) e 0,10 (ISPxP420). A seleção direta para perímetro escrotal aos 420 dias de idade poderá resultar em progresso genético favoráveis na assiduidade reprodutiva de fêmeas da raça Canchim, considerando que o PE420 apresentou correlação genética aditiva com idade ao segundo parto

Nebular abundances of southern symbiotic stars

We have calculated relative elemental abundances for a sample of 43 symbiotic stars. Helium abundances and the relative elemental abundances N/O, Ne/O, Ar/O were derived from new spectra collected in the optical range through low dispersion spectroscopy. The He ionic abundances were derived taking into account self-absorption effects in Balmer lines. We found that the symbiotic stars in the galactic bulge have heavy element abundances showing the same wide distribution as other bulge objects. In the galactic disk, the symbiotic stars follow the abundance gradient as derived from different kinds of objects.Comment: 12 pages, 6 figures, A&A - accepte

Estimativas de parâmetros genéticos para peso corporal, gordura abdominal e peso de peles em linhagem pura de frangos de corte.

Projeto: 02.09.07.006