1,519 research outputs found

    Workplace exposure to passive smoking and risk of cardiovascular disease: summary of epidemiologic studies.

    Get PDF
    We reviewed the published epidemiologic studies addressing the relationship between workplace exposure to environmental tobacco smoke (ETS) and cardiovascular disease risk in three case-control studies and three cohort studies. Although the point estimates of risk for cardiovascular disease exceeded 1.0 in five of six studies, none of the relative risks was statistically significant because of the small number of cardiovascular end points occurring in individual studies. In common with most epidemiologic investigations of the health risks of ETS, none of the workplace studies included independent biochemical validation of ETS exposure. In contrast to the evidence on increased cardiovascular disease risk from exposure to spousal ETS, studies of ETS exposure in the workplace are still sparse and inconclusive. Conversely, there is no biologically plausible reason to believe that the hazards of ETS exposure that have been demonstrated in the home should not also apply to the workplace

    Perceptions of Neighborhood Safety and Asthma among Children and Adolescents in Los Angeles: A Multilevel Analysis

    Get PDF
    Background: Research examining the impact of neighborhoods on asthma has shown an increased interest in the role of the psychosocial environment. We examined the associations between various measures of neighborhood safety, individual and family characteristics, and asthma outcomes among children in Los Angeles. Methods: Multilevel logistic regression models were used to analyze data on 3,114 children across 65 neighborhoods from Wave 1 of the Los Angeles Family and Neighborhood Survey (2000 to 2002). Primary caregivers reported asthma outcome and all individual covariates; home environmental characteristics were observed by the interviewer. Results: In fully adjusted models, parents who reported their neighborhood fairly safe or somewhat dangerous had lower odds of reported lifetime asthma compared to those who reported their neighborhood completely safe (OR 0.71; 95% CI 0.52–0.96 and OR 0.60; 95% CI 0.42–0.88 respectively). Conversely, parents who reported they could not trust their neighbors to keep their children safe had a nearly 40% increase in lifetime asthma compared to those who reported they could trust their neighbors to keep their children safe (OR 1.39; 95% CI 1.07–1.81). Conclusions: The study demonstrates a complex pattern between various measures of neighborhood safety and asthma and suggests that these relationships may operate differently in Los Angeles. As an increasing proportion of children are growing up in newer Western and Southwestern cities, which have different physical layouts and residential segregation patterns compared to Northeast and Midwestern cities, future studies should continue to examine neighborhood psychosocial stressors and asthma in diverse contexts

    Characterisation and Mechanical Testing of Hydrothermally Treated HA/ZrO2 Composites

    Get PDF
    Hydrothermal treatment is traditionally employed to improve the sinterability of powder compacts by reducing porosity and increasing apparent density. The effect of hydrothermal treatment on green powder compacts has been assessed in order to better understand how treatment may affect the sinter ability of the bodies. Laboratory synthesized nano sized hydroxyapatite (HA) and a commercial zirconia (ZrO2) powder have been ball milled together to create composite mixtures containing 0-5 wt% ZrO2 loadings. Disc shaped bodies have been formed using uniaxial and subsequent isostatic pressure. The resultant coherent samples were subjected to hydrothermal treatment at either 120 or 250°C for 10 h in order to assess the effect of this processing technique on the physical, mechanical and microstructural properties of the green composites. ZrO2 loadings up to 3 wt% increased apparent density from 90 to 92%, whereas increased loading to 5 wt% increased flexural strength, from 6 to 9 MPa. Increasing the hydrothermal treatment temperature increased open porosity, from ~44 to ~48% and reduced biaxial flexural strengths of the treated bodies compared to those of their room temperature isostatically pressed counterparts (~10 to ~6 MPa). © 2009 Springer Science+Business Media, LLC

    Free Trade Agreements and World Obesity

    Get PDF
    We study the causal link between trade openness via free trade agreements and obesity rates. We apply a difference-in-differences approach and exploit the year a country entered a free trade agreement with the United States during the period 1990 to 2016. We find statistically and economically significant results and show that our findings are robust to placebo tests, the use of synthetic control methods, and mechanically maximizing the sample. Additionally, we show that when using event studies the equal trends assumption holds

    Observations of the supernova remnant W28 at TeV energies

    Get PDF
    The atmospheric Cerenkov imaging technique has been used to search for point-like and diffuse TeV gamma-ray emission from the southern supernova remnant, W28, and surrounding region. The search, made with the CANGAROO 3.8m telescope, encompasses a number of interesting features, the supernova remnant itself, the EGRET source 3EG J1800-2338, the pulsar PSR J1801-23, strong 1720 MHz OH masers and molecular clouds on the north and east boundaries of the remnant. An analysis tailored to extended and off-axis point sources was used, and no evidence for TeV gamma-ray emission from any of the features described above was found in data taken over the 1994 and 1995 seasons. Our upper limit (E>1.5 TeV) for a diffuse source of radius 0.25deg encompassing both molecular clouds was calculated at 6.64e-12 photons cm^-2 s^-1 (from 1994 data), and interpreted within the framework of a model predicting TeV gamma-rays from shocked-accelerated hadrons. Our upper limit suggests the need for some cutoff in the parent spectrum of accelerated hadrons and/or slightly steeper parent spectra than that used here (-2.1). As to the nature of 3EG J1800-2338, it possibly does not result entirely from pi-zero decay, a conclusion also consistent with its location in relation to W28.Comment: 11 pages, 5 figures. Accepted for publication in Astronomy and Astrophysic

    TeV observations of Centaurus A

    Get PDF
    We have searched for TeV gamma-rays from Centaurus A and surrounding region out to +/- 1.0 deg using the CANGAROO 3.8m telescope. No evidence for TeV gamma-ray emission was observed from the search region, which includes a number of interesting features located away from the tracking centre of our data. The 3 sigma upper limit to the flux of gamma-rays above 1.5 TeV from an extended source of radius 14' centred on Centaurus A is 1.28e-11 photons cm^-2 s^-1.Comment: 4 pages. Astroparticle Physics, accepted for publication. Some upper limits overestimated by factor 2-4 in original version astro-ph/9901316. Now correcte
    • 

    corecore