12,789 research outputs found

    The Near-Infrared Photometric Properties of Bright Giants in the Central Regions of the Galactic Bulge

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    Images recorded through broad (J, H, K), and narrow (CO, and 2.2micron continuum) band filters are used to investigate the photometric properties of bright (K < 13.5) stars in a 6 x 6 arcmin field centered on the SgrA complex. The giant branch ridgelines in the (K, J-K) and (K, H-K) color-magnitude diagrams are well matched by the Baade's Window (BW) M giant sequence if the mean extinction is A_K ~ 2.8 mag. Extinction measurements for individual stars are estimated using the M_K versus infrared color relations defined by M giants in BW, and the majority of stars have A_K between 2.0 and 3.5 mag. The extinction is locally high in the SgrA complex, where A_K ~ 3.1 mag. Reddening-corrected CO indices, CO_o, are derived for over 1300 stars with J, H, and K brightnesses, and over 5300 stars with H and K brightnesses. The distribution of CO_o values for stars with K_o between 11.25 and 7.25 can be reproduced using the M_K versus CO_o relation defined by M giants in BW. The data thus suggest that the most metal-rich giants in the central regions of the bulge and in BW have similar photometric properties and 2.3micron CO strengths. Hence, it appears that the central region of the bulge does not contain a population of stars that are significantly more metal-rich than what is seen in BW.Comment: 29 pages, including 14 figure

    Ending Human Trafficking: A Stakeholder’s Challenge

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    The paper analyzes the concepts, theories, causes, and methods of human trafficking as culled from various contemporary policy capacity literature which tackle human trafficking as thematic consideration and topical affair. It posits the question of the what, why, and how of human trafficking and attempts to answer these questions using an integrative review approach of literature. A critical component of the paper is its analysis and discussion on the current and prevailing stakeholder institutions, actors and agents engage in human trafficking and the corresponding challenges, opportunities and directions it needs to do to stop human traffickin

    Perspectives for Positron Emission Tomography with RPCs

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    In this study we address the feasibility and main properties of a positron emission tomograph (PET) based on RPCs. The concept, making use of the converter-plate principle, takes advantage of the intrinsic layered structure of RPCs and its simple and economic construction. The extremely good time and position resolutions of RPCs also allow the TOF-PET imaging technique to be considered. Monte-Carlo simulations, supported by experimental data, are presented and the main advantages and drawbacks for applications of potential interest are discussed.Comment: Presented at "RPC2001-VI Workshop on Resistive Plate Chambers and Related Detectors", Coimbra, Portugal, 26-27 November 2001 (5 pages
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