34,168 research outputs found

    Mission design for a ballistic slow flyby Comet Encke 1980

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    Preliminary mission analyses for a proposed 1980 slow flyby (7-9 km/s) of comet Encke are presented. Among the topics covered are science objectives, Encke's physical activity and ephemeris accuracy, trajectory and launch-window analysis, terminal guidance, and spacecraft concepts. The nominal mission plan calls for a near-perihelion intercept with two spacecraft launched on a single launch vehicle. Both spacecraft will arrive at the same time, one passing within 500 km from Encke's nucleus on its sunward side, the other cutting through the tail region. By applying a small propulsive correction about three weeks after the encounter, it is possible to retarget both spacecraft for a second Encke intercept in 1984. The potential science return from the ballistic slow flyby is compared with other proposed mission modes for the 1980 Encke flyby mission, including the widely advocated slow flyby using solar-electric propulsion. It is shown that the ballistic slow flyby is superior in every respect

    Aiming Higher: Results From a State Scorecard on Health System Performance, 2009

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    Ranks states on thirty-eight indicators of healthcare access, prevention and treatment, avoidable hospital use and costs, equity, and healthy lives. Examines trends, including eroding adult insurance coverage, poor care coordination, and rising costs

    Aiming Higher: Results From a State Scorecard on Health System Performance

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    Assesses state variation across key dimensions of health system performance -- access, quality, avoidable hospital use and costs, equity, and healthy lives -- and assigns overall state rankings as well as ranks on each dimension

    Securing a Healthy Future: The Commonwealth Fund State Scorecard on Child Health System Performance, 2011

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    Ranks states on twenty indicators of healthcare access, affordability, prevention and treatment, potential for healthy lives, and health system equity for children. Examines the need for targeted initiatives and policy implications for better performance
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