7,826 research outputs found

    Reinforcing the link between the double red clump and the X-shaped bulge of the Milky Way

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    The finding of a double red clump in the luminosity function of the Milky Way bulge has been interpreted as evidence for an X-shaped structure. Recently, an alternative explanation has been suggested, where the double red clump is an effect of multiple stellar populations in a classical spheroid. In this Letter we provide an observational assessment of this scenario and show that it is not consistent with the behaviour of the red clump across different lines of sight, particularly at high distances from the Galactic plane. Instead, we confirm that the shape of the red clump magnitude distribution closely follows the distance distribution expected for an X-shaped bulge at critical Galactic latitudes. We also emphasize some key observational properties of the bulge red clump that should not be neglected in the search for alternative scenarios

    Beryllium abundances in stars hosting giant planets

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    We have derived beryllium abundances in a wide sample of stars hosting planets, with spectral types in the range F7V-K0V, aimed at studying in detail the effects of the presence of planets on the structure and evolution of the associated stars. Predictions from current models are compared with the derived abundances and suggestions are provided to explain the observed inconsistencies. We show that while still not clear, the results suggest that theoretical models may have to be revised for stars with Teff<5500K. On the other hand, a comparison between planet host and non-planet host stars shows no clear difference between both populations. Although preliminary, this result favors a ``primordial'' origin for the metallicity ``excess'' observed for the planetary host stars. Under this assumption, i.e. that there would be no differences between stars with and without giant planets, the light element depletion pattern of our sample of stars may also be used to further investigate and constraint Li and Be depletion mechanisms.Comment: A&A in press -- accepted on the 22/02/2002 (11 pages, 6 figures included

    Herida antebraquial infectada por Aeromonas hydrophila

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    Se presenta un caso de celulitis por Aeromonas hydrophila, en un paciente de 23 años, tras una herida antebraquial producida en el medio acuático. La celulitis se resolvió mediante desbridamiento agresivo y quimioterapia. En los controles posteriores no se han apreciado déficits funcionales tras la infección.A case of Aeromonas hidrophila cellulitis developped in a 23-year-old patient, after aquatic environment forearm wound is presented. His cellulitis was effectively resolved with aggressive debridement and chemotherapy. Follow-up examinations have shown no residual functional deficits from the infection

    Spatial distribution of small hydrocarbons in the neighborhood of the Ultra Compact HII region Monoceros R2

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    We study the chemistry of small hydrocarbons in the photon-dominated regions (PDRs) associated with the ultra-compact HII region Mon R2. Our goal is to determine the variations of the abundance of small hydrocarbons in a high-UV irradiated PDR and investigate their chemistry. We present an observational study of CH, CCH and c-C3_3H2_2 in Mon R2 combining data obtained with the IRAM 30m telescope and Herschel. We determine the column densities of these species, and compare their spatial distributions with that of polycyclic aromatic hydrocarbon (PAH). We compare the observational results with different chemical models to explore the relative importance of gas-phase, grain-surface and time-dependent chemistry in these environments. The emission of the small hydrocarbons show different patterns. The CCH emission is extended while CH and c-C3_3H2_2 are concentrated towards the more illuminated layers of the PDR. The ratio of the column densities of c-C3_3H2_2 and CCH shows spatial variations up to a factor of a few, increasing from N(cCN(c-C_3HH_2)/N(CCH)0.004)/N(CCH)\approx0.004 in the envelope to a maximum of 0.0150.029\sim0.015-0.029 towards the 8μ\mum emission peak. Comparing these results with other galactic PDRs, we find that the abundance of CCH is quite constant over a wide range of G0_0, whereas the abundance of c-C3_3H2_2 is higher in low-UV PDRs. In Mon R2, the gas-phase steady-state chemistry can account relatively well for the abundances of CH and CCH in the most exposed layers of the PDR, but falls short by a factor of 10 to reproduce c-C3_3H2_2. In the molecular envelope, time-dependent effects and grain surface chemistry play a dominant role in determining the hydrocarbons abundances. Our study shows that CCH and c-C3_3H2_2 present a complex chemistry in which UV photons, grain-surface chemistry and time dependent effects contribute to determine their abundances.Comment: 18 pages, 11 figures, 7 tables. Proposed for acceptance in A&A. Abstract abridge

    Influence of alternating air injection on the color and <em>“alambrado”</em> of natural black olives cv. Arauco, as compared with the traditional Argentine method

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    Ripe black olives cv. Arauco were processed under different conditions to evaluate the effects of alternating air injection (AI) on the color of olives and on spoilage known as “<em>alambrado</em>”, using a system based on the one patented by the “Instituto de la Grasa” (Sevilla, Spain), as compared with the traditional Argentine processing method, which consists of drying the olives in natural air (“<em>extendido</em>”) for 24 hours at 7, 14 and 21 days of fermentation. Four types of fermentation were used: brine at 2% NaCl plus AI; brine at 2% NaCl plus three “<em>extendidos</em>”; brine at 9% NaCl plus three “<em>extendido</em>s”; and brine at 9% NaCl plus AI and one “<em>extendido</em>”. As previously observed in other varieties by other authors, we noticed that lower pH values were achieved in 2% NaCl fermentations vs. 9% NaCl fermentations. AI prevented the “<em>alambrado</em>” whereas brine at 2% NaCl reduced this spoilage as compared with brine at 9% NaCl. The darkest color of olives was obtained with three “<em>extendido</em>s”, but 83% of brightness reduction was achieved with only one “<em>extendido</em>”. The “<em>extendido</em>” process decreased the texture. We conclude that the combination of AI and “<em>extendido</em>” can add benefits to natural black olives of the Arauco variety.<br><br>Se elaboraron aceitunas negras maduras variedad Arauco en distintas condiciones para evaluar la inyección alternante de aire (IA) con un sistema basado en el patentado por el Instituto de la Grasa, en comparación con la elaboración tradicional argentina donde se realiza exposición al aire en seco (“extendido”) de los frutos durante 24 h, en tres momentos de la fermentación (después de 7, 14 y 21 días). Se hicieron cuatro tipos de fermentaciones: en salmuera al 2% con IA; en salmuera al 2% y 9% con tres “extendidos” y salmuera 9% con IA y un “extendido”. Se alcanzaron los valores mas bajos de pH en fermentaciones con el 2% de NaCl versus las de 9%. La IA evita el defecto de “alambrado” y lo reduce la concentración de 2% versus la de 9%. El color más oscuro se obtiene aplicando el “extendido” en tres oportunidades, pero con una aplicación se alcanza el 83% de la reducción de luminosidad alcanzada por las tres aplicaciones. La textura se ve disminuida por el proceso de “extendido”. La combinación de la IA y el “extendido” reducen el defecto de “alambrado” y oscurecen las aceitunas negras al natural de la variedad Arauco

    Are beryllium abundances anomalous in stars with giant planets?

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    In this paper we present beryllium (Be) abundances in a large sample of 41 extra-solar planet host stars, and for 29 stars without any known planetary-mass companion, spanning a large range of effective temperatures. The Be abundances were derived through spectral synthesis done in standard Local Thermodynamic Equilibrium, using spectra obtained with various instruments. The results seem to confirm that overall, planet-host stars have ``normal'' Be abundances, although a small, but not significant, difference might be present. This result is discussed, and we show that this difference is probably not due to any stellar ``pollution'' events. In other words, our results support the idea that the high-metal content of planet-host stars has, overall, a ``primordial'' origin. However, we also find a small subset of planet-host late-F and early-G dwarfs that might have higher than average Be abundances. The reason for the offset is not clear, and might be related either to the engulfment of planetary material, to galactic chemical evolution effects, or to stellar-mass differences for stars of similar temperature.Comment: 15 pages, 9 figures, accepted for publication in Astronomy & Astrophysic

    Adding genetic scores to risk models in colorectal cancer

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    Colorectal cancer (CRC) represents the second most common cancer worldwide and the third leading cause of cancer death. Most CRCs arise from premalignant colorectal lesions (mainly adenomas) that require years to develop an invasive disease..

    Beryllium anomalies in solar-type field stars

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    We present a study of beryllium (Be) abundances in a large sample of field solar-type dwarfs and sub-giants spanning a large range of effective temperatures. The analysis shows that Be is severely depleted for F stars, as expected by the light-element depletion models. However, we also show that Beryllium abundances decrease with decreasing temperature for stars cooler than \sim6000 K, a result that cannot be explained by current theoretical models including rotational mixing, but that is, at least in part, expected from the models that take into account internal wave physics. In particular, the light element abundances of the coolest and youngest stars in our sample suggest that Be, as well as lithium (Li), has already been burned early during their evolution. Furthermore, we find strong evidence for the existence of a Be-gap for solar-temperature stars. The analysis of Li and Be abundances in the sub-giants of our sample also shows the presence of one case that has still detectable amounts of Li, while Be is severely depleted. Finally, we compare the derived Be abundances with Li abundances derived using the same set of stellar parameters. This gives us the possibility to explore the temperatures for which the onset of Li and Be depletion occurs.Comment: 16 pages, 13 figures, accepted for publication in Astronomy & Astrophysic

    Engineered microenvironments for synergistic VEGF - integrin signalling during vascularization

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    We have engineered polymer-based microenvironments that promote vasculogenesis both in vitro and in vivo through synergistic integrin-growth factor receptor signalling. Poly(ethyl acrylate) (PEA) triggers spontaneous organization of fibronectin (FN) into nanonetworks which provide availability of critical binding domains. Importantly, the growth factor binding (FNIII12-14) and integrin binding (FNIII9-10) regions are simultaneously available on FN fibrils assembled on PEA. This material platform promotes synergistic integrin/VEGF signalling which is highly effective for vascularization events in vitro with low concentrations of VEGF. VEGF specifically binds to FN fibrils on PEA compared to control polymers (poly(methyl acrylate), PMA) where FN remains in a globular conformation and integrin/GF binding domains are not simultaneously available. The vasculogenic response of human endothelial cells seeded on these synergistic interfaces (VEGF bound to FN assembled on PEA) was significantly improved compared to soluble administration of VEGF at higher doses. Early onset of VEGF signalling (PLCγ1 phosphorylation) and both integrin and VEGF signalling (ERK1/2 phosphorylation) were increased only when VEGF was bound to FN nanonetworks on PEA, while soluble VEGF did not influence early signalling. Experiments with mutant FN molecules with impaired integrin binding site (FN-RGE) confirmed the role of the integrin binding site of FN on the vasculogenic response via combined integrin/VEGF signalling. In vivo experiments using 3D scaffolds coated with FN and VEGF implanted in the murine fat pad demonstrated pro-vascularization signalling by enhanced formation of new tissue inside scaffold pores. PEA-driven organization of FN promotes efficient presentation of VEGF to promote vascularization in regenerative medicine applications
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