10 research outputs found

    The Detection and Statistics of Giant Arcs Behind CLASH Clusters

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    We developed an algorithm to find and characterize gravitationally lensed galaxies (arcs) to perform a comparison of the observed and simulated arc abundance. Observations are from the Cluster Lensing And Supernova survey with Hubble (CLASH). Simulated CLASH images are created using the MOKA package and also clusters selected from the high-resolution, hydrodynamical simulations, MUSIC, over the same mass and redshift range as the CLASH sample. The algorithm's arc elongation accuracy, completeness, and false positive rate are determined and used to compute an estimate of the true arc abundance. We derive a lensing efficiency of 4 ± 1 arcs (with length ≥6'' and length-to-width ratio ≥7) per cluster for the X-ray-selected CLASH sample, 4 ± 1 arcs per cluster for the MOKA-simulated sample, and 3 ± 1 arcs per cluster for the MUSIC-simulated sample. The observed and simulated arc statistics are in full agreement. We measure the photometric redshifts of all detected arcs and find a median redshift z_s = 1.9 with 33% of the detected arcs having z_s > 3. We find that the arc abundance does not depend strongly on the source redshift distribution but is sensitive to the mass distribution of the dark matter halos (e.g., the c–M relation). Our results show that consistency between the observed and simulated distributions of lensed arc sizes and axial ratios can be achieved by using cluster-lensing simulations that are carefully matched to the selection criteria used in the observations

    Cluster Lensing And Supernova survey with Hubble (CLASH): An Overview

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    The Cluster Lensing And Supernova survey with Hubble (CLASH) is a 524-orbit multi-cycle treasury program to use the gravitational lensing properties of 25 galaxy clusters to accurately constrain their mass distributions. The survey, described in detail in this paper, will definitively establish the degree of concentration of dark matter in the cluster cores, a key prediction of CDM. The CLASH cluster sample is larger and less biased than current samples of space-based imaging studies of clusters to similar depth, as we have minimized lensing-based selection that favors systems with overly dense cores. Specifically, twenty CLASH clusters are solely X-ray selected. The X-ray selected clusters are massive (kT > 5 keV; 5 - 30 x 10^14 M_solar) and, in most cases, dynamically relaxed. Five additional clusters are included for their lensing strength (Einstein radii > 35 arcsec at z_source = 2) to further quantify the lensing bias on concentration, to yield high resolution dark matter maps, and to optimize the likelihood of finding highly magnified high-redshift (z > 7) galaxies. The high magnification, in some cases, provides angular resolutions unobtainable with any current UVOIR facility and can yield z > 7 candidates bright enough for spectroscopic follow-up. A total of 16 broadband filters, spanning the near-UV to near-IR, are employed for each 20-orbit campaign on each cluster. These data are used to measure precise (sigma_phz < 0.02(1+z)) photometric redshifts for dozens of newly discovered multiply-lensed images per cluster. Observations of each cluster are spread over 8 epochs to enable a search, primarily in the parallel fields, for Type Ia supernovae at z > 1 to improve constraints on the time dependence of the dark energy equation of state and the evolution of such supernovae in an epoch when the universe is matter dominated.Comment: Accepted for publication in the Astrophysical Journal Supplements, 22 pages, 16 figures. Updated Tables 3,4,8 and figures 6 and 8 to reflect replacement of Abell 963 with Abell 1423 in CLASH survey. A963 cannot be observed with WFC3 due to the lack of usable guide star

    Modified Compositions of Micelle–Clay and Liposome–Clay Composites for Optimal Removal from Water of Bacteria and Hydrophobic Neutral Chemicals

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    The efficiency in water treatment by granulated complexes formed from the clay bentonite with (i) micelles of the cations of octadecyltrimethyl-ammonium (ODTMA) or (ii) liposomes of didodecyldimethyl-ammonium (DDAB) was investigated. The bentonite–ODTMA complexes were synthesized in three variations: I. mass ratio of 68/32, which resulted in an excess of positive charge of half of the clay cation exchange capacity and is denoted “ordinary”; II. complexes having higher loads of ODTMA, denoted “enriched”; and III. “neutral”. These variations were designed to optimize the efficiency and reduce the costs of water treatment. “Ordinary” and “neutral” complexes of DDAB were also synthesized. The “ordinary” complex of ODTMA was shown to be efficient in the removal of anionic/hydrophobic molecules and bacteria. The “enriched” complexes were more active in removal of bacteria from water by filtration due to the higher release of free ODTMA cations, which causes biostatic/biocidal effects. The corresponding “ordinary” and “neutral” complexes of ODTMA and DDAB yielded the same efficiency in removal from water of the neutral and hydrophobic herbicides, S-metolachlor (i) and alachlor (ii), respectively. Model calculations, which considered sorption/desorption and convection yielded simulations and predictions of filtration results of the herbicides. The neutral complexes are advantageous since their production saves about 1/3 of the amount of ODTMA or DDAB, which constitutes the expensive component in the respective composite

    Anti-TNFα Treatment Impairs Long-Term Immune Responses to COVID-19 mRNA Vaccine in Patients with Inflammatory Bowel Diseases

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    Patients with inflammatory bowel disease (IBD) treated with anti-tumor-necrosis factor-alpha (TNFα) exhibited lower serologic responses one-month following the second dose of the COVID-19 BNT162b2 vaccine compared to those not treated with anti-TNFα (non-anti-TNFα) or to healthy controls (HCs). We comprehensively analyzed long-term humoral responses, including anti-spike (S) antibodies, serum inhibition, neutralization, cross-reactivity and circulating B cell six months post BNT162b2, in patients with IBD stratified by therapy compared to HCs. Subjects enrolled in a prospective, controlled, multi-center Israeli study received two BNT162b2 doses. Anti-S levels, functional activity, specific B cells, antigen cross-reactivity, anti-nucleocapsid levels, adverse events and IBD disease score were detected longitudinally. In total, 240 subjects, 151 with IBD (94 not treated with anti-TNFα and 57 treated with anti-TNFα) and 89 HCs participated. Six months after vaccination, patients with IBD treated with anti-TNFα had significantly impaired BNT162b2 responses, specifically, more seronegativity, decreased specific circulating B cells and cross-reactivity compared to patients untreated with anti-TNFα. Importantly, all seronegative subjects were patients with IBD; of those, &gt;90% were treated with anti-TNFα. Finally, IBD activity was unaffected by BNT162b2. Altogether these data support the earlier booster dose administration in these patients

    Triangle or ‘trilemma’: Rousseau and the ‘Kantian peace’

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    Brain and Cognition for Addiction Medicine: From Prevention to Recovery Neural Substrates for Treatment of Psychostimulant-Induced Cognitive Deficits

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