1,964 research outputs found

    Sterile neutrinos in the Milky Way: Observational constraints

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    We consider the possibility of constraining decaying dark matter by looking out through the Milky Way halo. Specifically we use Chandra blank sky observations to constrain the parameter space of sterile neutrinos. We find that a broad band in parameter space is still open, leaving the sterile neutrino as an excellent dark matter candidate.Comment: Submitted to ApJL, 4 pages, 4 figure

    FDG-PET/CT(A) imaging in large vessel vasculitis and polymyalgia rheumatica:joint procedural recommendation of the EANM, SNMMI, and the PET Interest Group (PIG), and endorsed by the ASNC

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    Large vessel vasculitis (LVV) is defined as a disease mainly affecting the large arteries, with two major variants. Takayasu arteritis (TA) and giant cell arteritis (GCA). GCA often coexists with polymyalgia rheumatica (PMR) in the same patient, since both belong to the same disease spectrum. FDG-PET/CT is a functional imaging technique which is an established tool in oncology, and has also demonstrated a role in the field of inflammatory diseases. Functional FDG-PET combined with anatomical CT angiography, FDG-PET/CT(A), may be of synergistic value for optimal diagnosis, monitoring of disease activity, and evaluating damage progression in LVV There are currently no guidelines regarding PET imaging acquisition for LVV and PMR, even though standardization is of the utmost importance in order to facilitate clinical studies and for daily clinical practice. This work constitutes a joint procedural recommendation on FDG-PET/CT(A) imaging in large vessel vasculitis (LVV) and PMR from the Cardiovascular and Inflammation &amp; Infection Committees of the European Association of Nuclear Medicine (EANM), the Cardiovascular Council of the Society of Nuclear Medicine and Molecular Imaging (SNMMI), and the PET Interest Group (PIG), and endorsed by the American Society of Nuclear Cardiology (ASNC). The aim of this joint paper is to provide recommendations and statements, based on the available evidence in the literature and consensus of experts in the field, for patient preparation, and FDG-PET/CT(A) acquisition and interpretation for the diagnosis and follow-up of patients with suspected or diagnosed LVV and/or PMR. This position paper aims to set an internationally accepted standard for FDG-PET/CT(A) imaging and reporting of LVV and PMR.</p

    Emissions of Volatile Organic Compounds Inferred From Airborne Flux Measurements over a Megacity

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    Toluene and benzene are used for assessing the ability to measure disjunct eddy covariance (DEC) fluxes of Volatile Organic Compounds (VOC) using Proton Transfer Reaction Mass Spectrometry (PTR-MS) on aircraft. Statistically significant correlation between vertical wind speed and mixing ratios suggests that airborne VOC eddy covariance (EC) flux measurements using PTR-MS are feasible. City-median midday toluene and benzene fluxes are calculated to be on the order of 14.1&amp;plusmn;4.0 mg/m&lt;sup&gt;2&lt;/sup&gt;/h and 4.7&amp;plusmn;2.3 mg/m&lt;sup&gt;2&lt;/sup&gt;/h, respectively. For comparison the adjusted CAM2004 emission inventory estimates toluene fluxes of 10 mg/m&lt;sup&gt;2&lt;/sup&gt;/h along the footprint of the flight-track. Wavelet analysis of instantaneous toluene and benzene measurements during city overpasses is tested as a tool to assess surface emission heterogeneity. High toluene to benzene flux ratios above an industrial district (e.g. 10–15 g/g) including the International airport (e.g. 3–5 g/g) and a mean flux (concentration) ratio of 3.2&amp;plusmn;0.5 g/g (3.9&amp;plusmn;0.3 g/g) across Mexico City indicate that evaporative fuel and industrial emissions play an important role for the prevalence of aromatic compounds. Based on a tracer model, which was constrained by BTEX (BTEX– Benzene/Toluene/Ethylbenzene/m, p, o-Xylenes) compound concentration ratios, the fuel marker methyl-tertiary-butyl-ether (MTBE) and the biomass burning marker acetonitrile (CH&lt;sub&gt;3&lt;/sub&gt;CN), we show that a combination of industrial, evaporative fuel, and exhaust emissions account for &gt;87% of all BTEX sources. Our observations suggest that biomass burning emissions play a minor role for the abundance of BTEX compounds in the MCMA (2–13%)

    The Walk-in Counselling Model of Service Delivery: Who Benefits Most?

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    The walk-in counselling (WIC) model of service delivery has been found to reduce psychological distress more quickly than a traditional model of service delivery involving a wait list. A question remains, however, as to the relative benefit of the WIC model for different client groups. The present study uses graphical inspection and multilevel modeling to conduct moderator analyses comparing two agencies, one with a WIC clinic and the other with a traditional wait list approach, and their relative impact on psychological distress. Key findings regarding the differential benefits for different types of presenting problems as well as clients at different stages of change are discussed. La recherche montre qu\u27un service de consultation sans rendez-vous réduit la détresse psychologique plus rapidement qu\u27un modèle traditionnel fonctionnant avec liste d\u27attente. Les bénéfices relatifs du modèle de consultation sans rendez-vous pour différentes clientèles demeurent cependant méconnus. Cette étude utilise l\u27inspection de graphiques et la modélisation multiniveau afin de mener une analyse de modération qui compare deux cliniques: sans rendez-vous ou suivant le modèle traditionnel avec liste d\u27attente. L\u27étude examine les impacts relatifs de ces modèles sur la détresse psychologique. Les principaux résultats portent sur les bénéfices différentiels selon les problématiques de santé mentale présentées et selon les stades de changement des usagers

    Is having a sweetheart enough to survive?

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    Almost three decades after the description of improved left ventricular function caused by chronic impaired coronary perfusion, and the rise of the term “Hibernation,” finding that hibernating myocardium is still a challenge for cardiologists
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