2,501 research outputs found

    Re-evaluation of IIH as the Ideal Terrestrial Analog for Sans: Is There a Better Model to Consider?

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    While astronauts are returning from long duration spaceflight with multiple ocular signs that mimic those seen in terrestrial patients with elevated intracranial pressure (ICP), evidence has yet to prove a clinically significant increase in ICP during space.1 Preliminary research evidence may even suggest that ICP decreases in microgravity. Idiopathic intracranial hypertension (IIH) has long been considered the ideal terrestrial analogue to Spaceflight Associated Neuro-ocular Syndrome (SANS).1 However, there are several critical features of SANS that do not complement any reported case of IIH on Earth. These findings mandate a closer look at the accuracy of IIH as a terrestrial SANS analog

    Development and Validity of a Workplace Health Promotion Best Practices Assessment

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    Objective: To explore the factor structure of the HERO Health and Well-being Best Practices Scorecard in Collaboration with Mercer (HERO Scorecard) to develop a reduced version and examine the reliability and validity of that version. Methods: A reduced version of the HERO Scorecard was developed through formal statistical analyses on data collected from 845 organizations that completed the original HERO Scorecard. Results: The final factors in the reduced Scorecard represented content pertaining to organizational and leadership support, program comprehensiveness, program integration, and incentives. All four implemented practices were found to have a strong, statistically significant effect on perceived effectiveness. Organizational and leadership support had the strongest effect (β = 0.56), followed by incentives (β = 0.23). Conclusion: The condensed version of the HERO Scorecard has the potential to be a promising tool for future research on the extent to which employers are adopting best practices in their health and well-being (HWB) initiatives

    Workplace Well-Being Factors That Predict Employee Participation, Health and Medical Cost Impact, and Perceived Support

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    Purpose: This study tested relationships between health and well-being best practices and 3 types of outcomes. Design: A cross-sectional design used data from the HERO Scorecard Benchmark Database. Setting: Data were voluntarily provided by employers who submitted web-based survey responses. Sample: Analyses were limited to 812 organizations that completed the HERO Scorecard between January 12, 2015 and October 2, 2017. Measures: Independent variables included organizational and leadership support, program comprehensiveness, program integration, and incentives. Dependent variables included participation rates, health and medical cost impact, and perceptions of organizational support. Analysis: Three structural equation models were developed to investigate the relationships among study variables. Results: Model sample size varied based on organizationally reported outcomes. All models fit the data well (comparative fit index \u3e 0.96). Organizational and leadership support was the strongest predictor (P \u3c .05) of participation (n ¼ 276 organizations), impact (n ¼ 160 organizations), and perceived organizational support (n ¼ 143 organizations). Incentives predicted participation in health assessment and biometric screening (P \u3c .05). Program comprehensiveness and program integration were not significant predictors (P \u3e .05) in any of the models. Conclusion: Organizational and leadership support practices are essential to produce participation, health and medical cost impact, and perceptions of organizational support. While incentives influence participation, they are likely insufficient to yield downstream outcomes. The overall study design limits the ability to make causal inferences from the data

    Asymmetric function theory

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    The classical theory of symmetric functions has a central position in algebraic combinatorics, bridging aspects of representation theory, combinatorics, and enumerative geometry. More recently, this theory has been fruitfully extended to the larger ring of quasisymmetric functions, with corresponding applications. Here, we survey recent work extending this theory further to general asymmetric polynomials.Comment: 36 pages, 8 figures, 1 table. Written for the proceedings of the Schubert calculus conference in Guangzhou, Nov. 201

    Analysis by NASA's VESGEN Software of Retinal Blood Vessels in Human Subjects Undergoing Head-Down Tilt During 70-Day Bed Rest

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    Significant risks for visual impairment associated with increased intracranial pressure (VIIP) are incurred by microgravity spaceflight, especially long-duration missions [1]. We hypothesize that microgravity-induced fluid shifts result in pathological changes within blood vessels of the retina that precede development of visual and other ocular impairments. Potential contributions of retinal vascular remodeling to VIIP etiology are therefore being investigated for two studies in 30deg infrared (IR) Heidelberg Spectralis(Registered Trademark) images with NASA's innovative VESsel GENeration Analysis (VESGEN) software [2,3]. The retrospective studies include: (1) before, during and after (pre, mid and post) 6 head-down tilt (HDT) in human subjects during 70 days of bed rest, and (2) before and after missions to the International Space Station (ISS) by U.S. crew members. Results for both studies are almost complete. A preliminary example for HDT is described below

    First-principles extrapolation method for accurate CO adsorption energies on metal surfaces

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    We show that a simple first-principles correction based on the difference between the singlet-triplet CO excitation energy values obtained by DFT and high-level quantum chemistry methods yields accurate CO adsorption properties on a variety of metal surfaces. We demonstrate a linear relationship between the CO adsorption energy and the CO singlet-triplet splitting, similar to the linear dependence of CO adsorption energy on the energy of the CO 2π\pi* orbital found recently {[Kresse {\em et al.}, Physical Review B {\bf 68}, 073401 (2003)]}. Converged DFT calculations underestimate the CO singlet-triplet excitation energy ΔES−T\Delta E_{\rm S-T}, whereas coupled-cluster and CI calculations reproduce the experimental ΔES−T\Delta E_{\rm S-T}. The dependence of EchemE_{\rm chem} on ΔES−T\Delta E_{\rm S-T} is used to extrapolate EchemE_{\rm chem} for the top, bridge and hollow sites for the (100) and (111) surfaces of Pt, Rh, Pd and Cu to the values that correspond to the coupled-cluster and CI ΔES−T\Delta E_{\rm S-T} value. The correction reproduces experimental adsorption site preference for all cases and obtains EchemE_{\rm chem} in excellent agreement with experimental results.Comment: Table sent as table1.eps. 3 figure
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