277 research outputs found

    Coherent Cancellation of Photothermal Noise in GaAs/Al0.92_{0.92}Ga0.08_{0.08}As Bragg Mirrors

    Get PDF
    Thermal noise is a limiting factor in many high-precision optical experiments. A search is underway for novel optical materials with reduced thermal noise. One such pair of materials, gallium arsenide and aluminum-alloyed gallium arsenide (collectively referred to as AlGaAs), shows promise for its low Brownian noise when compared to conventional materials such as silica and tantala. However, AlGaAs has the potential to produce a high level of thermo-optic noise. We have fabricated a set of AlGaAs crystalline coatings, transferred to fused silica substrates, whose layer structure has been optimized to reduce thermo-optic noise by inducing coherent cancellation of the thermoelastic and thermorefractive effects. By measuring the photothermal transfer function of these mirrors, we find evidence that this optimization has been successful.Comment: 10 pages, 7 figure

    Broadband measurement of coating thermal noise in rigid Fabry–Pérot cavities

    Get PDF
    We report on the relative length fluctuation of two fixed-spacer Fabry–Pérot cavities with mirrors fabricated from silica/tantala dielectric coatings on fused silica substrates. By locking a laser to each cavity and reading out the beat note v = v_1− v_2 of the transmitted beams, we find that, for frequencies from 10 Hz to 1 kHz, the power spectral density of beat note fluctuation is S_v(f)=(0.5Hz)^2/f. By careful budgeting of noise sources contributing to the beat note, we find that our measurement is consistent with the fluctuation in this band being dominated by the Brownian noise of the mirror coatings. Fitting for the coating loss angle ⌽_c, we find it equal to 4 × 10^(−4). We then use a Bayesian analysis to combine our measurement with previous observations, and thereby extract estimates for the individual loss angles of the silica and tantala constituents of these coatings. With minor upgrades, the testbed described in this article can be used in the future to measure the length noise of cavities formed with novel mirror coating materials and geometries

    Mortality, morbidity, and hospitalisations due to influenza lower respiratory tract infections, 2017: an analysis for the Global Burden of Disease Study 2017

    Get PDF
    Background Although the burden of influenza is often discussed in the context of historical pandemics and the threat of future pandemics, every year a substantial burden of lower respiratory tract infections (LRTIs) and other respiratory conditions (like chronic obstructive pulmonary disease) are attributable to seasonal influenza. The Global Burden of Disease Study (GBD) 2017 is a systematic scientific effort to quantify the health loss associated with a comprehensive set of diseases and disabilities. In this Article, we focus on LRTIs that can be attributed to influenza. Methods We modelled the LRTI incidence, hospitalisations, and mortality attributable to influenza for every country and selected subnational locations by age and year from 1990 to 2017 as part of GBD 2017. We used a counterfactual approach that first estimated the LRTI incidence, hospitalisations, and mortality and then attributed a fraction of those outcomes to influenza. Findings Influenza LRTI was responsible for an estimated 145 000 (95% uncertainty interval [UI] 99 000–200 000) deaths among all ages in 2017. The influenza LRTI mortality rate was highest among adults older than 70 years (16·4 deaths per 100 000 [95% UI 11·6–21·9]), and the highest rate among all ages was in eastern Europe (5·2 per 100 000 population [95% UI 3·5–7·2]). We estimated that influenza LRTIs accounted for 9 459 000 (95% UI 3 709 000–22 935 000) hospitalisations due to LRTIs and 81 536 000 hospital days (24 330 000–259 851 000). We estimated that 11·5% (95% UI 10·0–12·9) of LRTI episodes were attributable to influenza, corresponding to 54 481 000 (38 465 000–73 864 000) episodes and 8 172 000 severe episodes (5 000 000–13 296 000). Interpretation This comprehensive assessment of the burden of influenza LRTIs shows the substantial annual effect of influenza on global health. Although preparedness planning will be important for potential pandemics, health loss due to seasonal influenza LRTIs should not be overlooked, and vaccine use should be considered. Efforts to improve influenza prevention measures are needed. Funding Bill & Melinda Gates Foundation

    Alcohol consumption pattern in western Nepal:Findings from the COBIN baseline survey

    Get PDF
    Background: Harmful use of alcohol is a global public health problem. Differences in alcohol consumption patterns may add valuable information to the design of public health interventions to prevent excessive use of alcohol, which is yet missing in Nepal. Hence, the purpose of the study is to determine the prevalence, patterns of alcohol consumption and socio-economic correlates of lifetime alcohol consumption and binge drinking in the semi-urban area of Pokhara Municipality. Methods: The cross-sectional data used in this study were collected as part of the COBIN study to understand alcohol consumption patterns and frequency and to determine correlates of lifetime alcohol consumption and binge drinking in the semi-urban area of Pokhara Municipality, Nepal. Results: Out of 2815 study participants, 35.6% had ever used alcohol in their lifetime (Male 67.2% and Female 18.9%). Among 571 respondents who drank alcohol within the past 30 days, 77.1% male, and 46.9% female reported binge drinking behaviour. On average, males consumed 8.8 ± 0.3 standard alcohol drinks on one occasion, while females consumed only 4.4 ± 0.3 alcoholic drinks. Male (OR = 16; 95% CI: 12.1-21.1), older adults (OR = 1.5; 95% CI: 1.2-1.7) and people belonging to disadvantaged ethnic group (OR = 6.1; 95% CI: 4.9-6.3) had higher odds of lifetime alcohol consumption than their respective counterparts. Whereas, male (OR = 7.9; 95% CI: 4.3-14.6), having higher educational status and agriculture as the occupation had higher odds of binge drinking. Conclusion: Alcohol consumption frequency was significantly higher among males than females in Western Nepal. Although national program and policies should recommend reducing alcohol consumption in general, targeted interventions are needed for males aged 45-65 years of age and certain ethnic groups (Dalit and Janajati).</p

    Maritime doctors’ skills and competencies:A review for policy analysis

    Get PDF
    Maritime medicine deals with the health of seafarers, fishermen, and offshore employees and, more specifically, with their employment, working and living conditions, and their health and safety at sea. Maritime doctors should have the appropriate training and competencies to provide the equivalent service as would be found on land. This review discusses a) the required skills and competencies of maritime doctors and b) explores the associated ongoing discussions for the establishment of a global accredited Masters programme in maritime health. A literature review was conducted using 2 databases: PubMed and Google scholar. Search terms included: maritime doctors, maritime medicine, occupational health, and skills and competencies. Literature published between 1990 and 2018 was prioritised. Thirty-five articles that discussed the skills, competencies, and education of maritime doctors and health professionals were retrieved, reviewed, and discussed, plus 8 reports and documents from relevant International Organisations webpages. We explored policies in relation to training using i) the health triangle and ii) the Kingdon model. Doctors who serve in the sector should have extensive knowledge about medical practice, but also about the environment of seafaring. The complexity of their roles, coupled with the provision of a high quality of services in global shipping, call for high quality accredited training and harmonisation of maritime health practices. The analysis of policy, using 2 policy models, showed that a window of opportunity appears to be in favour of a policy regarding the recognition of maritime medicine as a medical specialisation. International stakeholders, together with the International Maritime Health Association, should actively advocate such a perspective which will be in favour of seafarers, who will enjoy better health and wellbeing, with higher income while avoiding ill-health, as well as the shipping industry, which will employ satisfied and loyal employees, and will enjoy a higher reputation.</p

    Prevalence and attributable health burden of chronic respiratory diseases, 1990–2017: a systematic analysis for the Global Burden of Disease Study 2017

    Get PDF
    Background Previous attempts to characterise the burden of chronic respiratory diseases have focused only on specific disease conditions, such as chronic obstructive pulmonary disease (COPD) or asthma. In this study, we aimed to characterise the burden of chronic respiratory diseases globally, providing a comprehensive and up-to-date analysis on geographical and time trends from 1990 to 2017. Methods Using data from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2017, we estimated the prevalence, morbidity, and mortality attributable to chronic respiratory diseases through an analysis of deaths, disability-adjusted life-years (DALYs), and years of life lost (YLL) by GBD super-region, from 1990 to 2017, stratified by age and sex. Specific diseases analysed included asthma, COPD, interstitial lung disease and pulmonary sarcoidosis, pneumoconiosis, and other chronic respiratory diseases. We also assessed the contribution of risk factors (smoking, second-hand smoke, ambient particulate matter and ozone pollution, household air pollution from solid fuels, and occupational risks) to chronic respiratory disease-attributable DALYs. Findings In 2017, 544·9 million people (95% uncertainty interval [UI] 506·9–584·8) worldwide had a chronic respiratory disease, representing an increase of 39·8% compared with 1990. Chronic respiratory disease prevalence showed wide variability across GBD super-regions, with the highest prevalence among both males and females in high-income regions, and the lowest prevalence in sub-Saharan Africa and south Asia. The age-sex-specific prevalence of each chronic respiratory disease in 2017 was also highly variable geographically. Chronic respiratory diseases were the third leading cause of death in 2017 (7·0% [95% UI 6·8–7·2] of all deaths), behind cardiovascular diseases and neoplasms. Deaths due to chronic respiratory diseases numbered 3 914 196 (95% UI 3 790 578–4 044 819) in 2017, an increase of 18·0% since 1990, while total DALYs increased by 13·3%. However, when accounting for ageing and population growth, declines were observed in age-standardised prevalence (14·3% decrease), agestandardised death rates (42·6%), and age-standardised DALY rates (38·2%). In males and females, most chronic respiratory disease-attributable deaths and DALYs were due to COPD. In regional analyses, mortality rates from chronic respiratory diseases were greatest in south Asia and lowest in sub-Saharan Africa, also across both sexes. Notably, although absolute prevalence was lower in south Asia than in most other super-regions, YLLs due to chronic respiratory diseases across the subcontinent were the highest in the world. Death rates due to interstitial lung disease and pulmonary sarcoidosis were greater than those due to pneumoconiosis in all super-regions. Smoking was the leading risk factor for chronic respiratory disease-related disability across all regions for men. Among women, household air pollution from solid fuels was the predominant risk factor for chronic respiratory diseases in south Asia and sub-Saharan Africa, while ambient particulate matter represented the leading risk factor in southeast Asia, east Asia, and Oceania, and in the Middle East and north Africa super-region. Interpretation Our study shows that chronic respiratory diseases remain a leading cause of death and disability worldwide, with growth in absolute numbers but sharp declines in several age-standardised estimators since 1990. Premature mortality from chronic respiratory diseases seems to be highest in regions with less-resourced health systems on a per-capita basis

    Mortality, morbidity, and hospitalisations due to influenza lower respiratory tract infections, 2017: an analysis for the Global Burden of Disease Study 2017

    Get PDF
    Background Although the burden of influenza is often discussed in the context of historical pandemics and the threat of future pandemics, every year a substantial burden of lower respiratory tract infections (LRTIs) and other respiratory conditions (like chronic obstructive pulmonary disease) are attributable to seasonal influenza. The Global Burden of Disease Study (GBD) 2017 is a systematic scientific effort to quantify the health loss associated with a comprehensive set of diseases and disabilities. In this Article, we focus on LRTIs that can be attributed to influenza. Methods We modelled the LRTI incidence, hospitalisations, and mortality attributable to influenza for every country and selected subnational locations by age and year from 1990 to 2017 as part of GBD 2017. We used a counterfactual approach that first estimated the LRTI incidence, hospitalisations, and mortality and then attributed a fraction of those outcomes to influenza. Findings Influenza LRTI was responsible for an estimated 145 000 (95% uncertainty interval [UI] 99 000–200 000) deaths among all ages in 2017. The influenza LRTI mortality rate was highest among adults older than 70 years (16·4 deaths per 100 000 [95% UI 11·6–21·9]), and the highest rate among all ages was in eastern Europe (5·2 per 100 000 population [95% UI 3·5–7·2]). We estimated that influenza LRTIs accounted for 9 459000 (95% UI 3 709000–22 935000) hospitalisations due to LRTIs and 81 536 000 hospital days (24 330 000–259851 000). We estimated that 11·5% (95% UI 10·0–12·9) of LRTI episodes were attributable to influenza, corresponding to 54481 000 (38465000–73864000) episodes and 8172000 severe episodes (5 000 000–13 296000). Interpretation This comprehensive assessment of the burden of influenza LRTIs shows the substantial annual effect of influenza on global health. Although preparedness planning will be important for potential pandemics, health loss due to seasonal influenza LRTIs should not be overlooked, and vaccine use should be considered. Efforts to improve influenza prevention measures are needed

    Individual patient-centered target-driven intervention to improve clinical outcomes of diabetes, health literacy, and self-care practices in Nepal: A randomized controlled trial

    Get PDF
    Purpose: To examine the effectiveness of a culturally and linguistically appropriate, patient-centered, target-driven lifestyle intervention with video education training in improving clinical outcomes, health literacy, and diabetic self-care practices in newly diagnosed patients in Nepal. Methods: A total of 110 participants with newly and consequently diagnosed Type 2 were randomly allocated into intervention (mean age = 45 ± 9.7 years) and control (mean age = 47 ± 12.5 years) groups. Intervention group participants were trained on a culturally and linguistically appropriate diabetic video education program and were given a customized dietary and physical activity plan with specific targets to practice at home. Participants’ compliance was monitored weekly via telephone calls. Both groups received the usual treatment from their doctor and were followed up after three months. Outcome measures included changes in: i. diabetic health literacy, diet, and physical activity measured using self-reported questionnaires; and ii. blood glucose (glycated hemoglobin, HbA1c), cholesterol, blood pressure, body mass index, and visual acuity. Clinical outcome measures were blinded from randomization and intervention allocation. Results: After three months, HbA1c decreased to 6.1% from the baseline value of 7.2% in the intervention group compared to 6.6% in the control group from the baseline value of 7.1% (p <0.05). The intervention group had mean total cholesterol and low-density lipoprotein of 174 and 95.5 mg/dL, which were significantly lower than 186 and 107.5 mg/dL in the control group. Daily white rice consumption decreased by 36.5% in the intervention vs. 4% in the control group (p <0.05). After three months, the intervention group participants exercised more than the control group (p <0.05). All intervention group participants self-initiated retinal screening checks since the baseline visit among which 13% showed early diabetic retinopathy signs compared to 0% in the control group. Health literacy improvement in the intervention group was found to be sustained after three months too. Conclusions: A culturally appropriate, target-driven lifestyle intervention with video education training is effective in improving clinical outcomes, health literacy, and self-care practice in newly diagnosed diabetic patients in Nepal, i.e., at a time period when effective diabetes control is vital to prevent further complications. The training intervention could be rolled out nationwide in order to reduce the risk of diabetic-related complications and improve people’s quality of life and productivity
    corecore