76 research outputs found

    Rhapsody-G simulations: galaxy clusters as baryonic closed boxes and the covariance between hot gas and galaxies

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    Within a sufficiently large cosmic volume, conservation of baryons implies a simple `closed box' view in which the sum of the baryonic components must equal a constant fraction of the total enclosed mass. We present evidence from Rhapsody-G hydrodynamic simulations of massive galaxy clusters that the closed-box expectation may hold to a surprising degree within the interior, non-linear regions of haloes. At a fixed halo mass, we find a significant anti-correlation between hot gas mass fraction and galaxy mass fraction (cold gas + stars), with a rank correlation coefficient of -0.69 within R500cR_{500c}. Because of this anti-correlation, the total baryon mass serves as a low-scatter proxy for total cluster mass. The fractional scatter of total baryon fraction scales approximately as 0.02(Δc/100)0.60.02 (\Delta_c/100)^{0.6}, while the scatter of either gas mass or stellar mass is larger in magnitude and declines more slowly with increasing radius. We discuss potential observational tests using cluster samples selected by optical and hot gas properties; the simulations suggest that joint selection on stellar and hot gas has potential to achieve 5% scatter in total halo mass.Comment: 10 pages, 6 figures, 3 tables; replaced to match published versio

    RHAPSODY-G simulations II - Baryonic growth and metal enrichment in massive galaxy clusters

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    We study the evolution of the stellar component and the metallicity of both the intracluster medium and of stars in massive (Mvir6×1014M_{\rm vir}\approx 6\times 10^{14} M/h_{\odot}/h) simulated galaxy clusters from the Rhapsody-G suite in detail and compare them to observational results. The simulations were performed with the AMR code RAMSES and include the effect of AGN feedback at the sub-grid level. AGN feedback is required to produce realistic galaxy and cluster properties and plays a role in mixing material in the central regions and regulating star formation in the central galaxy. In both our low and high resolution runs with fiducial stellar yields, we find that stellar and ICM metallicities are a factor of two lower than in observations. We find that cool core clusters exhibit steeper metallicity gradients than non-cool core clusters, in qualitative agreement with observations. We verify that the ICM metallicities measured in the simulation can be explained by a simple "regulator" model in which the metallicity is set by a balance of stellar yield and gas accretion. It is plausible that a combination of higher resolution and higher metal yield in AMR simulation would allow the metallicity of simulated clusters to match observed values; however this hypothesis needs to be tested with future simulations. Comparison to recent literature highlights that results concerning the metallicity of clusters and cluster galaxies might depend sensitively on the scheme chosen to solve the hydrodynamics.Comment: 22 pages, 11 figures, 2 tables. Accepted for publication on MNRA

    Rhapsody-G simulations: galaxy clusters as baryonic closed boxes and the covariance between hot gas and galaxies

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    Within a sufficiently large cosmic volume, conservation of baryons implies a simple ‘closed box' view in which the sum of the baryonic components must equal a constant fraction of the total enclosed mass. We present evidence from Rhapsody-G hydrodynamic simulations of massive galaxy clusters that the closed-box expectation may hold to a surprising degree within the interior, non-linear regions of haloes. At a fixed halo mass, we find a significant anti-correlation between hot gas mass fraction and galaxy mass fraction (cold gas+stars), with a rank correlation coefficient of −0.69 within R500c. Because of this anti-correlation, the total baryon mass serves as a low-scatter proxy for total cluster mass. The fractional scatter of total baryon fraction scales approximately as 0.02(Δc/100)0.6, while the scatter of either gas mass or stellar mass is larger in magnitude and declines more slowly with increasing radius. We discuss potential observational tests using cluster samples selected by optical and hot gas properties; the simulations suggest that joint selection on stellar and hot gas has potential to achieve 5 per cent scatter in total halo mas

    Effects on the maternofetal unit of the rabbit model after substitution of the amniotic fluid with perfluorocarbons

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    Objectives: Exchanging amniotic fluid (AF) with perfluorocarbon (PFC) may serve as a medium for fetoscopic surgery. This study evaluates the distribution and physiologic effects of intraamniotic PFC as a medium for fetoscopy. Methods: Fetuses of 17 pregnant rabbits underwent either exchange of the AF with PFC, electrolyte solution (ES), or control. The quality of vision during fetoscopy was assessed in AF and PFC. After 6 h, we determined the distribution of PFC in the maternofetal unit. Results: Quality of vision during fetoscopy was better in PFC than with AF. There was no difference in fetal survival between the study groups. PFC was demonstrated on X-ray in the pharynx of 4 fetuses, and the esophagus in 1. Conclusions: PFC provided an ideal medium for fetoscopy without fetal compromise. Copyright (c) 2005 S. Karger AG, Basel

    A Neutrophil Timer Coordinates Immune Defense and Vascular Protection

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    Neutrophils eliminate pathogens efficiently but can inflict severe damage to the host if they over-activate within blood vessels. It is unclear how immunity solves the dilemma of mounting an efficient anti-microbial defense while preserving vascular health. Here, we identify a neutrophil-intrinsic program that enabled both. The gene Bmal1 regulated expression of the chemokine CXCL2 to induce chemokine receptor CXCR2-dependent diurnal changes in the transcriptional and migratory properties of circulating neutrophils. These diurnal alterations, referred to as neutrophil aging, were antagonized by CXCR4 (C-X-C chemokine receptor type 4) and regulated the outer topology of neutrophils to favor homeostatic egress from blood vessels at night, resulting in boosted anti-microbial activity in tissues. Mice engineered for constitutive neutrophil aging became resistant to infection, but the persistence of intravascular aged neutrophils predisposed them to thrombo-inflammation and death. Thus, diurnal compartmentalization of neutrophils, driven by an internal timer, coordinates immune defense and vascular protection. Neutrophils display circadian oscillations in numbers and phenotype in the circulation. Adrover and colleagues now identify the molecular regulators of neutrophil aging and show that genetic disruption of this process has major consequences in immune cell trafficking, anti-microbial defense, and vascular health.This study was supported by Intramural grants from A∗STAR to L.G.N., BES-2013-065550 to J.M.A., BES-2010-032828 to M.C.-A, and JCI-2012-14147 to L.A.W (all from Ministerio de Economía, Industria y Competitividad; MEIC). Additional MEIC grants were SAF2014-61993-EXP to C.L.-R.; SAF2015-68632-R to M.A.M. and SAF-2013-42920R and SAF2016-79040Rto D.S. D.S. also received 635122-PROCROP H2020 from the European Commission and ERC CoG 725091 from the European Research Council (ERC). ERC AdG 692511 PROVASC from the ERC and SFB1123-A1 from the Deutsche Forschungsgemeinschaft were given to C.W.; MHA VD1.2/81Z1600212 from the German Center for Cardiovascular Research (DZHK) was given to C.W. and O.S.; SFB1123-A6 was given to O.S.; SFB914-B08 was given to O.S. and C.W.; and INST 211/604-2, ZA 428/12-1, and ZA 428/13-1 were given to A.Z. This study was also supported by PI12/00494 from Fondo de Investigaciones Sanitarias (FIS) to C.M.; PI13/01979, Cardiovascular Network grant RD 12/0042/0054, and CIBERCV to B.I.; SAF2015-65607-R, SAF2013-49662-EXP, and PCIN-2014-103 from MEIC; and co-funding by Fondo Europeo de Desarrollo Regional (FEDER) to A.H. The CNIC is supported by the MEIC and the Pro CNIC Foundation and is a Severo Ochoa Center of Excellence (MEIC award SEV-2015-0505)

    A Neutrophil Timer Coordinates Immune Defense and Vascular Protection

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    Neutrophils eliminate pathogens efficiently but can inflict severe damage to the host if they over-activate within blood vessels. It is unclear how immunity solves the dilemma of mounting an efficient anti-microbial defense while preserving vascular health. Here, we identify a neutrophil-intrinsic program that enabled both. The gene Bmal1 regulated expression of the chemokine CXCL2 to induce chemokine receptor CXCR2-dependent diurnal changes in the transcriptional and migratory properties of circulating neutrophils. These diurnal alterations, referred to as neutrophil aging, were antagonized by CXCR4 (C-X-C chemokine receptor type 4) and regulated the outer topology of neutrophils to favor homeostatic egress from blood vessels at night, resulting in boosted anti-microbial activity in tissues. Mice engineered for constitutive neutrophil aging became resistant to infection, but the persistence of intravascular aged neutrophils predisposed them to thrombo-inflammation and death. Thus, diurnal compartmentalization of neutrophils, driven by an internal timer, coordinates immune defense and vascular protection.We thank all members of the Hidalgo Lab for discussion and insightful comments; J.M. Ligos, R. Nieto, and M. Viton for help with sorting and cytometric analyses; I. Ortega and E. Santos for animal husbandry; D. Rico, M.J. Gomez, C. Torroja, and F. Sanchez-Cabo for insightful comments and help with transcriptomic analyses; V. Labrador, E. Arza, A.M. Santos, and the Microscopy Unit of the CNIC for help with microscopy; S. Aznar-Benitah, U. Albrecht, Q.-J. Meng, B. Staels, and H. Duez for the generous gift of mice; J.A. Enriquez and J. Avila for scientific insights; and J.M. Garcia and A. Diez de la Cortina for art. This study was supported by Intramural grants from A* STAR to L.G.N., BES-2013-065550 to J.M.A., BES-2010-032828 to M.C.-A, and JCI-2012-14147 to L.A.W (all from Ministerio de Economia, Industria y Competitividad; MEIC). Additional MEIC grants were SAF2014-61993-EXP to C.L.-R.; SAF2015-68632-R to M.A.M. and SAF-2013-42920R and SAF2016-79040Rto D.S. D.S. also received 635122-PROCROP H2020 from the European Commission and ERC CoG 725091 from the European Research Council (ERC). ERC AdG 692511 PROVASC from the ERC and SFB1123-A1 from the Deutsche Forschungsgemeinschaft were given to C.W.; MHA VD1.2/81Z1600212 from the German Center for Cardiovascular Research (DZHK) was given to C.W. and O.S.; SFB1123-A6 was given to O.S.; SFB914-B08 was given to O.S. and C.W.; and INST 211/604-2, ZA 428/12-1, and ZA 428/13-1 were given to A.Z. This study was also supported by PI12/00494 from Fondo de Investigaciones Sanitarias (FIS) to C.M.; PI13/01979, Cardiovascular Network grant RD 12/0042/0054, and CIBERCV to B.I.; SAF2015-65607-R, SAF2013-49662-EXP, and PCIN-2014-103 from MEIC; and co-funding by Fondo Europeo de Desarrollo Regional (FEDER) to A.H. The CNIC is supported by the MEIC and the Pro CNIC Foundation and is a Severo Ochoa Center of Excellence (MEIC award SEV-2015-0505).S

    GEO-6 assessment for the pan-European region

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    Through this assessment, the authors and the United Nations Environment Programme (UNEP) secretariat are providing an objective evaluation and analysis of the pan-European environment designed to support environmental decision-making at multiple scales. In this assessment, the judgement of experts is applied to existing knowledge to provide scientifically credible answers to policy-relevant questions. These questions include, but are not limited to the following:• What is happening to the environment in the pan-European region and why?• What are the consequences for the environment and the human population in the pan-European region?• What is being done and how effective is it?• What are the prospects for the environment in the future?• What actions could be taken to achieve a more sustainable future?<br/

    A Spitzer survey of Deep Drilling Fields to be targeted by the Vera C. Rubin Observatory Legacy Survey of Space and Time

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    The Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST) will observe several Deep Drilling Fields (DDFs) to a greater depth and with a more rapid cadence than the main survey. In this paper, we describe the ‘DeepDrill’ survey, which used the Spitzer Space Telescope Infrared Array Camera (IRAC) to observe three of the four currently defined DDFs in two bands, centred on 3.6 and 4.5 μm. These observations expand the area that was covered by an earlier set of observations in these three fields by the Spitzer Extragalactic Representative Volume Survey (SERVS). The combined DeepDrill and SERVS data cover the footprints of the LSST DDFs in the Extended Chandra Deep Field–South (ECDFS) field, the ELAIS-S1 field (ES1), and the XMM-Large-Scale Structure Survey field (XMM-LSS). The observations reach an approximate 5σ point-source depth of 2 μJy (corresponding to an AB magnitude of 23.1; sufficient to detect a 10¹¹M⊙ galaxy out to z ≈ 5) in each of the two bands over a total area of ≈29 deg². The dual-band catalogues contain a total of 2.35 million sources. In this paper, we describe the observations and data products from the survey, and an overview of the properties of galaxies in the survey. We compare the source counts to predictions from the SHARK semi-analytic model of galaxy formation. We also identify a population of sources with extremely red ([3.6]−[4.5] >1.2) colours which we show mostly consists of highly obscured active galactic nuclei
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