28 research outputs found

    The inner structure of early-type galaxies in the Illustris simulation

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    © 2017 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society Early-type galaxies provide unique tests for the predictions of the cold dark matter cosmology and the baryonic physics assumptions entering models for galaxy formation. In this work, we use the Illustris simulation to study correlations of three main properties of early-type galaxies, namely the stellar orbital anisotropies, the central dark matter fractions and the central radial density slopes, as well as their redshift evolution since z = 1.0. We find that lower mass galaxies or galaxies at higher redshift tend to be bluer in rest-frame colour, have higher central gas fractions, and feature more tangentially anisotropic orbits and steeper central density slopes than their higher mass or lower redshift counterparts, respectively. The projected central dark matter fraction within the effective radius shows a very mild mass dependence but positively correlates with galaxy effective radii due to the aperture effect. The central density slopes obtained by combining strong lensing measurements with single-aperture kinematics are found to differ from the true density slopes. We identify systematic biases in this measurement to be due to two common modelling assumptions, isotropic stellar orbital distributions and power-law density profiles. We also compare the properties of early-type galaxies in Illustris to those from existing galaxy and strong lensing surveys; we find in general broad agreement but also some tension, which poses a potential challenge to the stellar formation and feedback models adopted by the simulation

    Molecular epidemiology of Staphylococcus aureus in post-earthquake northern Haiti

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    Background: Knowledge of nasal carriage is important in predicting staphylococcal infection, and no information exists regarding the endemicity of Staphylococcus aureus in Haiti. Methods: We performed a cross-sectional analysis of S. aureus nasal screening in an acute care, a subacute rehabilitation, and a community setting, with a brief medical and epidemiological history. PCR-positive S. aureus screening nasal cultures underwent molecular analysis for spa type, SCCmec type, and virulence genes (Panton–Valentine leukocidin (PVL), toxic shock syndrome toxin (TSST), and arginine catabolic mobile element (ACME)), and were evaluated for antibiotic susceptibility using commercial tests. Results: Overall carriage rates of 8.4% methicillin-susceptible S. aureus (MSSA) and 2.8% methicillin-resistant S. aureus (MRSA) were identified, with a high rate of tetracycline resistance. TSST and PVL genes were identified in MSSA. MRSA isolates contained no virulence markers. Unique MSSA phenotypes (i.e., linezolid-resistant, vancomycin-sensitive/daptomycin non-susceptible) were identified, as were two PVL-positive ST152 MSSA colonization isolates, previously geographically limited to Africa. Conclusions: We found a low S. aureus carriage rate with complete vancomycin susceptibility and high tetracycline resistance, which has important public health implications with regard to treatment. Additionally, the finding of PVL-positive MSSA isolates, including the expansion of a previously described limited ‘divergent’ clone, ST152, warrants further evaluation

    Réparation de poésie no 11 : Poésie réparée fraßche

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    The eleventh issue of Quebec collective RĂ©paration de poĂ©sie’s annual publication gathers together 82 small objects, created by 57 artists from around the world whose goal is to develop an international Mail Art network. Most of the contributions, which borrow from collage, political art and the Fluxus movement, include text and images that attempt to create links between poetry and the visual arts. Some of the themes broached by the artists include: the environment, media and information technology, the body, travelling, the sacred, art and society, and the origin and future of humanity. Texts in numerous languages (French, English, Spanish, Italian, Chinese, etc.) Introductory text in French
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