772 research outputs found

    Natural Rolling Responses of a Delta Wing in Transonic and Subsonic Flows

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    The unsteady, three-dimensional, full Navier-Stokes (NS) equations and the Euler equations of rigid-body dynamics are sequentially solved to simulate the natural rolling response of slender delta wings of zero thickness at moderate to high angles of attack, to transonic and subsonic flows. The governing equations of fluid flow and dynamics of the present multi-disciplinary problem are solved using the time-accurate solution of the NS equations with the implicit, upwind, Roe flux-difference splitting, finite-volume scheme and a four-stage Runge-Kutta scheme, respectively. The main focus is to analyze the effect of Mach number and angle of attack on the leading edge vortices and their breakdown, the resultant rolling motion, and overall aerodynamic response of the wing. Three cases demonstrate the natural response of a 65 deg swept, cropped delta wing in a transonic flow with breakdown of the leading edge vortices and an 80 deg swept delta wing in a subsonic flow undergoing either damped or self-excited limit-cycle rolling oscillations as a function of angle of attack. Comparisons with an experimental investigation completes this study, validating the analysis and illustrating the complex details afforded by computational investigations

    Pneumococcal vaccination uptake among patients aged 65 years or over in Australian general practice

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    In Australia, pneumococcal vaccine is provided free to all adults aged ≥65 years and Indigenous people aged 15-65 years, and is subsidised for non-Indigenous adults <65 years of age with risk factors. This study aimed to explore pneumococcal vaccination uptake in older patients attending 550 Australian general practice from 2010-2017 by patient sociodemographics, presence of comorbidities and practice characteristics. Study 1: a cross-sectional analysis of 'active' patients aged ≥65 years in each year was performed to calculate annual pneumococcal vaccination uptake. Study 2: a cohort of 58,589 'every year' patients aged 60-65 years in 2010 was analysed to identify the number of patients immunised during the study period. Logistic regression models assessed associations between vaccination, patient and practice characteristics. Annual pneumococcal vaccine uptake varied by patient's age (65-74 or ≥75 years), presence of comorbidities and regularity of practice visits (range 36% to 76%), and it declined slowly from 2011-2016 amongst all groups. Cohort analyses showed that 69% of those aged 60-65 years in 2010 had a recorded pneumococcal vaccination by 2017 (peak age of vaccination = 66 years), and vaccination was more likely among those with comorbidities, ex-smokers and frequent attenders to practices. Findings demonstrate that the NPS MedicineInsight database provides estimates of vaccination uptake consistent with past surveys, reproducible every year and at low cost. It has the advantage of additional clinical information compared to the Australian Immunisation Register. Whilst vaccination uptake was adequate among 'every year' patients, interventions are needed to improve pneumococcal vaccination for all older Australians.Oliver Frank, Carla De Oliveira Bernardo, David Alejandro González-Chica, Kristine Macartney, Robert Menzies and Nigel Stock

    Analysis of multi drug resistant tuberculosis (MDR-TB) financial protection policy : MDR-TB health insurance schemes, in Chhattisgarh state, India

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    INTRODUCTION: There are significant financial barriers to access treatment for multi drug resistant tuberculosis (MDR-TB) in India. To address these challenges, Chhattisgarh state in India has established a MDR-TB financial protection policy by creating MDR-TB benefit packages as part of the universal health insurance scheme that the state has rolled out in their effort towards attaining Universal Health Coverage for all its residents. In these schemes the state purchases health insurance against set packages of services from third party health insurance agencies on behalf of all its residents. Provider payment reform by strategic purchasing through output based payments (lump sum fee is reimbursed as per the MDR-TB benefit package rates) to the providers - both public and private health facilities empanelled under the insurance scheme was the key intervention. AIM: To understand the implementation gap between policy and practice of the benefit packages with respect to equity in utilization of package claims by the poor patients in public and private sector. METHODS: Data from primary health insurance claims from January 2013 to December 2015, were analysed using an extension of 'Kingdon's multiple streams for policy implementation framework' to explain the implementation gap between policy and practice of the MDR-TB benefit packages. RESULTS: The total number of claims for MDR-TB benefit packages increased over the study period mainly from poor patients treated in public facilities, particularly for the pre-treatment evaluation and hospital stay packages. Variations and inequities in utilizing the packages were observed between poor and non-poor beneficiaries in public and private sector. Private providers participation in the new MDR-TB financial protection mechanism through the universal health insurance scheme was observed to be much lower than might be expected given their share of healthcare provision overall in India. CONCLUSION: Our findings suggest that there may be an implementation gap due to weak coupling between the problem and the policy streams, reflecting weak coordination between state nodal agency and the state TB department. There is a pressing need to build strong institutional capacity of the public and private sector for improving service delivery to MDR-TB patients through this new health insurance mechanism

    Tuberculosis screening of travelers to higher-incidence countries: A cost-effectiveness analysis

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    Abstract Background Travelers to countries with high tuberculosis incidence can acquire infection during travel. We sought to compare four screening interventions for travelers from low-incidence countries, who visit countries with varying tuberculosis incidence. Methods Decision analysis model: We considered hypothetical cohorts of 1,000 travelers, 21 years old, visiting Mexico, the Dominican Republic, or Haiti for three months. Travelers departed from and returned to the United States or Canada; they were born in the United States, Canada, or the destination countries. The time horizon was 20 years, with 3% annual discounting of future costs and outcomes. The analysis was conducted from the health care system perspective. Screening involved tuberculin skin testing (post-travel in three strategies, with baseline pre-travel tests in two), or chest radiography post-travel (one strategy). Returning travelers with tuberculin conversion (one strategy) or other evidence of latent tuberculosis (three strategies) were offered treatment. The main outcome was cost (in 2005 US dollars) per tuberculosis case prevented. Results For all travelers, a single post-trip tuberculin test was most cost-effective. The associated cost estimate per case prevented ranged from 21,406forHaitianborntravelerstoHaiti,to21,406 for Haitian-born travelers to Haiti, to 161,196 for US-born travelers to Mexico. In all sensitivity analyses, the single post-trip tuberculin test remained most cost-effective. For US-born travelers to Haiti, this strategy was associated with cost savings for trips over 22 months. Screening was more cost-effective with increasing trip duration and infection risk, and less so with poorer treatment adherence. Conclusion A single post-trip tuberculin skin test was the most cost-effective strategy considered, for travelers from the United States or Canada. The analysis did not evaluate the use of interferon-gamma release assays, which would be most relevant for travelers who received BCG vaccination after infancy, as in many European countries. Screening decisions should reflect duration of travel, tuberculosis incidence, and commitment to treat latent infection.</p
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