4,626 research outputs found
A Search for Intrinsic Polarization in O Stars with Variable Winds
New observations of 9 of the brightest northern O stars have been made with
the Breger polarimeter on the 0.9~m telescope at McDonald Observatory and the
AnyPol polarimeter on the 0.4~m telescope at Limber Observatory, using the
Johnson-Cousins UBVRI broadband filter system. Comparison with earlier
measurements shows no clearly defined long-term polarization variability. For
all 9 stars the wavelength dependence of the degree of polarization in the
optical range can be fit by a normal interstellar polarization law. The
polarization position angles are practically constant with wavelength and are
consistent with those of neighboring stars. Thus the simplest conclusion is
that the polarization of all the program stars is primarily interstellar.
The O stars chosen for this study are generally known from ultraviolet and
optical spectroscopy to have substantial mass loss rates and variable winds, as
well as occasional circumstellar emission. Their lack of intrinsic polarization
in comparison with the similar Be stars may be explained by the dominance of
radiation as a wind driving force due to higher luminosity, which results in
lower density and less rotational flattening in the electron scattering inner
envelopes where the polarization is produced. However, time series of
polarization measurements taken simultaneously with H-alpha and UV spectroscopy
during several coordinated multiwavelength campaigns suggest two cases of
possible small-amplitude, periodic short-term polarization variability, and
therefore intrinsic polarization, which may be correlated with the more widely
recognized spectroscopic variations.Comment: LaTeX2e, 22 pages including 11 tables; 12 separate gif figures; uses
aastex.cls preprint package; accepted by The Astronomical Journa
Aiming Higher: Results from a Scorecard on State Health System Performance, 2015 Edition
The fourth Commonwealth Fund Scorecard on State Health System Performance tells a story that is both familiar and new. Echoing the past three State Scorecards, the 2015 edition finds extensive variation among states in people's ability to access care when they need it, the quality of care they receive, and their likelihood of living a long and healthy life. However, this Scorecard—the first to measure the effects of the Affordable Care Act's 2014 coverage expansions—also finds broad-based improvements. On most of the 42 indicators, more states improved than worsened. By tracking performance measures across states, this Scorecard can help policymakers, health system leaders, and the public identify opportunities and set goals for improvement. The 50 states and the District of Columbia are measured and ranked on 42 indicators grouped into five domains: access and affordability, prevention and treatment, avoidable hospital use and cost, healthy lives, and equity. Individual indicators measure things like rates of children or adults who are uninsured, hospital patients who get information about how to handle their recovery at home, hospital admissions for children with asthma, and breast and colorectal cancer deaths, among many others
2018 Scorecard on State Health System Performance
Hawaii, Massachusetts, Minnesota, Vermont, and Utah are the top-ranked states according to the Commonwealth Fund's 2018 Scorecard on State Health System Performance, which assesses all 50 states and the District of Columbia on more than 40 measures of access to health care, quality of care, efficiency in care delivery, health outcomes, and income-based health care disparities.The 2018 Scorecard reveals that states are losing ground on key measures related to life expectancy. On most other measures, performance continues to vary widely across states; even within individual states, large disparities are common.Still, on balance, the Scorecard finds more improvement than decline between 2013 and 2016 in the functioning of state health care systems. This represents a reversal of sorts from the first decade of the century, when stagnating or worsening performance was the norm
Aiming Higher: Results from the Commonwealth Fund Scorecard on State Health System Performance, 2017 Edition
Issue: States are a locus of policy and leadership for health system performance.Goal: To compare and evaluate trends in health care access, quality, avoidable hospital use and costs, health outcomes, and health system equity across all 50 states and the District of Columbia.Methods: States are ranked on 44 performance measures using recently available data. Key findings: Nearly all states improved more than they worsened between 2013 and 2015. The biggest gains were in health insurance coverage and the ability to access care when needed, with states that had expanded their Medicaid programs under the Affordable Care Act experiencing the most improvement. There were also widespread state improvements on key indicators of treatment quality and patient safety; hospital patient readmissions also fell in many states. However, premature deaths crept up in almost two-thirds of states, reversing a long period of decline. Wide variations in performance across states persisted, as did disparities experienced by vulnerable populations within states.Conclusion: If every state achieved the performance of top-ranked states, their residents and the country as a whole would realize dramatic gains in health care access, quality, efficiency, and health outcomes
Health System Performance for the High-Need Patient: A Look at Access to Care and Patient Care Experiences
Achieving a high-performing health system will require improving outcomes and reducing costs for high-need, high-cost patients—those who use the most health care services and account for a disproportionately large share of health care spending. Goal: To compare the health care experiences of adults with high needs—those with three or more chronic diseases and a functional limitation in the ability to care for themselves or perform routine daily tasks—to all adults and to those with multiple chronic diseases but no functional limitations. Methods: Analysis of data from the 2009–2011 Medical Expenditure Panel Survey. Key findings: High-need adults were more likely to report having an unmet medical need and less likely to report having good patient–provider communication. High-need adults reported roughly similar ease of obtaining specialist referrals as other adults and greater likelihood of having a medical home. While adults with private health insurance reported the fewest unmet needs overall, privately insured highneed adults reported the greatest difficulties having their needs met. Conclusion: The health care system needs to work better for the highest-need, most-complex patients. This study's findings highlight the importance of tailoring interventions to address their need
Changing experience with dual chamber (DDD) pacemakers
Dual chamber (DDD) or “universal” pacemakers have had a significant impact on the advancement of artificial pacemakers by providing a more physiologic approach to cardiac pacing. However, with the early generation of DDD pacemakers (pacemakers that sense and pace in both the atrium and the ventricle), a significant number of patients experienced pacemaker-mediated tachycardia because intact ventriculoatrial conduction was sensed in the atrium and a reentrant tachycardia was induced. Newer generation DDD pacemakers have provided longer atrial refractory periods, which should correct this problem.In this study the first and second years of a 2 year experience with DDD pacemakers were compared to determine if the newer generation devices have allowed maintenance of pacing in the DDD mode as opposed to reprogramming to some alternate mode because of pacemaker-mediated tachycardia or other pacing problems. The results showed a significant decrease in pacemaker-mediated tachycardia during the second year and continuation of pacing in the DDD mode in a higher percent of patients. This improvement is attributed to improvement in the pulse generator as well as better patient selection
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