19 research outputs found

    Reopening the window on charged dark matter

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    We reexamine the limits on charged dark matter particles. We show that if their mass and charge fall in the range 100(q_X/e)^2< m_X < 10^8(q_X/e) TeV, then magnetic fields prevent particles in the halo from entering the galactic disk, while those initially trapped inside are accelerated through the Fermi mechanism and ejected within about 0.1-1 Gyrs. Consequently, previous constraints on charged dark matter based on terrestrial non-observation are invalid within that range. Further, we find that charged massive particles may simultaneously solve several long-standing astrophysical problems, including the underabundance of dwarf galaxies, the shallow density profiles in the cores of the LSB galaxies, the absence of cooling flows in the cores of galaxy clusters, and several others.Comment: 9 pages, 1 figure, accepted for publication in JCA

    The Physics of Star Cluster Formation and Evolution

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    © 2020 Springer-Verlag. The final publication is available at Springer via https://doi.org/10.1007/s11214-020-00689-4.Star clusters form in dense, hierarchically collapsing gas clouds. Bulk kinetic energy is transformed to turbulence with stars forming from cores fed by filaments. In the most compact regions, stellar feedback is least effective in removing the gas and stars may form very efficiently. These are also the regions where, in high-mass clusters, ejecta from some kind of high-mass stars are effectively captured during the formation phase of some of the low mass stars and effectively channeled into the latter to form multiple populations. Star formation epochs in star clusters are generally set by gas flows that determine the abundance of gas in the cluster. We argue that there is likely only one star formation epoch after which clusters remain essentially clear of gas by cluster winds. Collisional dynamics is important in this phase leading to core collapse, expansion and eventual dispersion of every cluster. We review recent developments in the field with a focus on theoretical work.Peer reviewe

    Genome-wide association study of lung adenocarcinoma in East Asia and comparison with a European population

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    Lung adenocarcinoma is the most common type of lung cancer. Known risk variants explain only a small fraction of lung adenocarcinoma heritability. Here, we conducted a two-stage genome-wide association study of lung adenocarcinoma of East Asian ancestry (21,658 cases and 150,676 controls; 54.5% never-smokers) and identified 12 novel susceptibility variants, bringing the total number to 28 at 25 independent loci. Transcriptome-wide association analyses together with colocalization studies using a Taiwanese lung expression quantitative trait loci dataset (n = 115) identified novel candidate genes, including FADS1 at 11q12 and ELF5 at 11p13. In a multi-ancestry meta-analysis of East Asian and European studies, four loci were identified at 2p11, 4q32, 16q23, and 18q12. At the same time, most of our findings in East Asian populations showed no evidence of association in European populations. In our studies drawn from East Asian populations, a polygenic risk score based on the 25 loci had a stronger association in never-smokers vs. individuals with a history of smoking (Pinteraction = 0.0058). These findings provide new insights into the etiology of lung adenocarcinoma in individuals from East Asian populations, which could be important in developing translational applications

    O programa de saúde escolar no município de Ribeirão Preto El programa de salud escolar en el municipio de Ribeirão Preto The primary school health care program at the municipality of Ribeirão Preto

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    O presente artigo relata a trajetória do Programa de Assistência Primária de Saúde Escolar (PROASE) no município de Ribeirão Preto e traz algumas reflexões sobre esta proposta.<br>El presente estudio relata el trayecto del Programa de Atención Primaria de Salud Escolar (PROASE) en el municipio de Ribeirão Preto y trae algunas reflexiones sobre esta propuesta.<br>The present article reports on the trajectory of the Primary School Health Care Program (PROASE) at the municipality of Ribeirão Preto and describes some reflections about this proposal
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