79 research outputs found

    LSST Science Book, Version 2.0

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    A survey that can cover the sky in optical bands over wide fields to faint magnitudes with a fast cadence will enable many of the exciting science opportunities of the next decade. The Large Synoptic Survey Telescope (LSST) will have an effective aperture of 6.7 meters and an imaging camera with field of view of 9.6 deg^2, and will be devoted to a ten-year imaging survey over 20,000 deg^2 south of +15 deg. Each pointing will be imaged 2000 times with fifteen second exposures in six broad bands from 0.35 to 1.1 microns, to a total point-source depth of r~27.5. The LSST Science Book describes the basic parameters of the LSST hardware, software, and observing plans. The book discusses educational and outreach opportunities, then goes on to describe a broad range of science that LSST will revolutionize: mapping the inner and outer Solar System, stellar populations in the Milky Way and nearby galaxies, the structure of the Milky Way disk and halo and other objects in the Local Volume, transient and variable objects both at low and high redshift, and the properties of normal and active galaxies at low and high redshift. It then turns to far-field cosmological topics, exploring properties of supernovae to z~1, strong and weak lensing, the large-scale distribution of galaxies and baryon oscillations, and how these different probes may be combined to constrain cosmological models and the physics of dark energy.Comment: 596 pages. Also available at full resolution at http://www.lsst.org/lsst/sciboo

    Fractionation of Li, Be, Ga, Nb, Ta, In, Sn, Sb, W and Bi in the peraluminous Early Permian Variscan granites of the Cornubian Batholith: precursor processes to magmatic-hydrothermal mineralisation

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    The Early Permian Variscan Cornubian Batholith is a peraluminous, composite pluton intruded into Devonian and Carboniferous metamorphosed sedimentary and volcanic rocks. Within the batholith there are: G1 (two-mica), G2 (muscovite), G3 (biotite), G4 (tourmaline) and G5 (topaz) granites. G1-G2 and G3-G4 are derived from greywacke sources and linked through fractionation of assemblages dominated by feldspars and biotite, with minor mantle involvement in G3. G5 formed though flux-induced biotite-dominate melting in the lower crust during granulite facies metamorphism. Fractionation enriched G2 granites in Li (average 315 ppm), Be (12 ppm), Ta (4.4 ppm), In (74 ppb), Sn (18 ppm) and W (12 ppm) relative to crustal abundances and G1 granites. Gallium (24 ppm), Nb (16 ppm) and Bi (0.46 ppm) are not significantly enriched during fractionation, implying they are more compatible in the fractionating assemblage. Sb (0.16 ppm) is depleted in G1-G2 relative to the average upper and lower continental crust. Muscovite, a late-stage magmatic/subsolidus mineral, is the major host of Li, Nb, In, Sn and W in G2 granites. G2 granites are spatially associated with W-Sn greisen mineralisation. Fractionation within the younger G3-G4 granite system enriched Li (average 364 ppm), Ga (28 ppm), In (80 ppb), Sn (14 ppm), Nb (27 ppm), Ta (4.6 ppm), W (6.3 ppm) and Bi (0.61 ppm) in the G4 granites with retention of Be in G3 granites due to partitioning of Be into cordierite during fractionation. The distribution of Nb and Ta is controlled by accessory phases such as rutile within the G4 granites, facilitated by high F and lowering the melt temperature, leading to disseminated Nb and Ta mineralisation. Lithium, In, Sn and W are hosted in biotite micas which may prove favourable for breakdown on ingress of hydrothermal fluids. Higher degrees of scattering on trace element plots may be attributable to fluid–rock interactions or variability within the magma chamber. The G3-G4 system is more boron-rich, evidenced by a higher modal abundance of tourmaline. In this system, there is a stronger increase of Sn compared to G1-G2 granites, implying Sn in tourmaline-dominated mineral lodes may represent exsolution from G4 granites. G1-G4 granite abundances can be accounted for by 20–30% partial melting and 10–40% fractionation of a greywacke source. G5 granites are analogues of Rare Metal Granites described in France and Germany. These granites are enriched in Li (average 1363 ppm), Ga (38 ppm), Sn (21 ppm), W (24 ppm), Nb (52 ppm) and Ta (15 ppm). Within G5 granites, the metals partition into accessory minerals such as rutile, columbite-tantalite and cassiterite, forming disseminated magmatic mineralisation. High observed concentrations of Li, In, Sn, W, Nb and Ta in G4 and G5 granites are likely facilitated by high F, Li and P, which lower melt temperature and promote retention of these elements in the melt, prior to crystallisation of disseminated magmatic mineralisation

    CDC Surveillance Strategy – A Strategy for Improving CDC Activities in Public Health Surveillance

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    Public health surveillance guides efforts to detect and monitor disease and injuries, assess the impact of interventions and assist in the management of and recovery from large-scale public health incidents. Actions informed by surveillance information take many forms, such as policy changes, new program interventions, public communications and investments in research. Local, state and federal public health professionals, government leaders, public health partners and the public are dependent on high quality, timely and actionable public health surveillance data. This Surveillance Strategy aims to improve overall surveillance capabilities, and by extension those of the public health system at large

    Infections in Long-Term-Care Facilities: Screen or Clean?

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    Health Systems: The Next Generation - Panel 2: Educating the Next Generation in Health Systems

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    Presented at the 1st forum on Health Systems: The Next Generation, September 16, 2016, Technology Square Research Building Georgia Tech, Atlanta, GA.Panel 2: Educating the Next Generation in Health Systems was moderated by Bill Todd, Professor in the Scheller College of Business, Georgia Tech.James (Jim) Curran, MD, MPH, is Dean at the Rollins School of Public Health, Emory University.Thomas Grace, MPH, is the Associate Medical Center Director at the Atlanta Veteran Affairs Medical Center.Amanda Mewborn, MSHS, is Executive Director, Project Management at Piedmont Hospital.Chesley Richards, MD, MPH, FACP, is Deputy Director for Public Health Scientific Services and Director, Office of Public Health Scientific Services, Centers for Disease Control and Prevention (CDC).Runtime: 84:12 minute
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