16,189 research outputs found

    Intra-group diffuse light in compact groups of galaxies. HCG 79, HCG 88 and HCG 95

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    Deep BB and RR images of three Hickson Compact Groups, HCG 79, HCG 88 and HCG 95, were analyzed using a new wavelet technic to measure possible intra-group diffuse light present in these systems. The method used, OV\_WAV, is a wavelet technic particularly suitable to detect low-surface brightness extended structures, down to a S/N=0.1S/N = 0.1 per pixel, which corresponds to a 5-σ\sigma-detection level in wavelet space. The three groups studied are in different evolutionary stages, as can be judged by their very different fractions of the total light contained in their intra-group halos: 46±1146\pm11% for HCG 79 and 11±2611\pm26% for HCG 95, in the BB band, and HCG 88 had no component detected down to a limiting surface brightness of 29.1Bmagarcsec229.1 B mag arcsec^{-2}. For HCG 95 the intra-group light is red, similar to the mean colors of the group galaxies themselves, suggesting that it is formed by an old population with no significant on-going star formation. For HCG 79, however, the intra-group material has significantly bluer color than the mean color of the group galaxies, suggesting that the diffuse light may, at least in part, come from stripping of dwarf galaxies which dissolved into the group potential well.Comment: Two suggested references added to the introductio

    The silicon stable isotope distribution along the GEOVIDE section (GEOTRACES GA-01) of the North Atlantic Ocean

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    The stable isotope composition of dissolved silicon in seawater (δ30SiDSi) was examined at 10 stations along the GEOVIDE section (GEOTRACES GA-01), spanning the North Atlantic Ocean (40–60∘ N) and Labrador Sea. Variations in δ30SiDSi below 500 m were closely tied to the distribution of water masses. Higher δ30SiDSi values are associated with intermediate and deep water masses of northern Atlantic or Arctic Ocean origin, whilst lower δ30SiDSi values are associated with DSi-rich waters sourced ultimately from the Southern Ocean. Correspondingly, the lowest δ30SiDSi values were observed in the deep and abyssal eastern North Atlantic, where dense southern-sourced waters dominate. The extent to which the spreading of water masses influences the δ30SiDSi distribution is marked clearly by Labrador Sea Water (LSW), whose high δ30SiDSi signature is visible not only within its region of formation within the Labrador and Irminger seas, but also throughout the mid-depth western and eastern North Atlantic Ocean. Both δ30SiDSi and hydrographic parameters document the circulation of LSW into the eastern North Atlantic, where it overlies southern-sourced Lower Deep Water. The GEOVIDE δ30SiDSi distribution thus provides a clear view of the direct interaction between subpolar/polar water masses of northern and southern origin, and allow examination of the extent to which these far-field signals influence the local δ30SiDSi distribution

    City-wide Analysis of Electronic Health Records Reveals Gender and Age Biases in the Administration of Known Drug-Drug Interactions

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    The occurrence of drug-drug-interactions (DDI) from multiple drug dispensations is a serious problem, both for individuals and health-care systems, since patients with complications due to DDI are likely to reenter the system at a costlier level. We present a large-scale longitudinal study (18 months) of the DDI phenomenon at the primary- and secondary-care level using electronic health records (EHR) from the city of Blumenau in Southern Brazil (pop. 340,000\approx 340,000). We found that 181 distinct drug pairs known to interact were dispensed concomitantly to 12\% of the patients in the city's public health-care system. Further, 4\% of the patients were dispensed drug pairs that are likely to result in major adverse drug reactions (ADR)---with costs estimated to be much larger than previously reported in smaller studies. The large-scale analysis reveals that women have a 60\% increased risk of DDI as compared to men; the increase becomes 90\% when considering only DDI known to lead to major ADR. Furthermore, DDI risk increases substantially with age; patients aged 70-79 years have a 34\% risk of DDI when they are dispensed two or more drugs concomitantly. Interestingly, a statistical null model demonstrates that age- and female-specific risks from increased polypharmacy fail by far to explain the observed DDI risks in those populations, suggesting unknown social or biological causes. We also provide a network visualization of drugs and demographic factors that characterize the DDI phenomenon and demonstrate that accurate DDI prediction can be included in healthcare and public-health management, to reduce DDI-related ADR and costs

    Effects of the size and concentration of depleting agents on the stabilization of the double-helix structure and DNA condensation: a single molecule force spectroscopy study

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    We perform a single molecule force spectroscopy study to characterize the role of the size (molecular weight) and concentration of depleting agents on DNA condensation and on the stabilization of the double-helix structure, showing that important features such as the threshold concentration for DNA condensation, the force in which the melting plateau occurs and its average length strongly depend on the depletant size chosen. Such results are potentially important to understand how the presence of surrounding macromolecules influences DNA stabilization inside living cells and therefore advance in the understanding of the crowded cell environment on DNA-related functions

    Variação genotípica na resposta antioxidativa de cultivares de Feijão-caupi expostos ao estresse osmótico.

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    The cowpea [Vigna unguiculata (L.) Walp.], also known as cowpea, is of fundamental socioeconomic importance to the northeast of Brazil, and has become one of the main sources of protein in the diet of the rural population. However, in this region, it has become necessary to identify genotypes that are better adapted to drought..

    Implantação do Banco Ativo de Germoplasma de pinheiro (Annona squamosa L.) na região do Submédio São Francisco.

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    O presente trabalho tem como objetivos: coletar, identificar, caracterizar, conservar, avaliar e selecionar genótipos promissores que possam ser incorporados em trabalhos de melhoramento genético visando o futuro lançamento de variedades recomendadas para cultivo na regiã
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