35 research outputs found

    Eff ectiveness of reactive oral cholera vaccination in rural Haiti: a case-control study and bias-indicator analysis

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    Background Between April and June, 2012, a reactive cholera vaccination campaign was done in Haiti with an oral inactivated bivalent whole-cell vaccine. We aimed to assess the eff ectiveness of the vaccine in a case-control study and to assess the likelihood of bias in that study in a bias-indicator study. Methods Residents of Bocozel or Grand Saline who were eligible for the vaccination campaign (ie, age ≄12 months, not pregnant, and living in the region at the time of the vaccine campaign) were included. In the primary case-control study, cases had acute watery diarrhoea, sought treatment at one of three participating cholera treatment units, and had a stool sample positive for cholera by culture. For each case, four control individuals who did not seek treatment for acute watery diarrhoea were matched by location of residence, enrolment time (within 2 weeks of the case), and age (1–4 years, 5–15 years, and >15 years). Cases in the bias-indicator study were individuals with acute watery diarrhoea with a negative stool sample for cholera. Controls were selected in the same manner as in the primary case-control study. Trained staff used standard laboratory procedures to do rapid tests and stool cultures from study cases. Participants were interviewed to collect data on sociodemographic characteristics, risk factors for cholera, and self-reported vaccination. Data were analysed by conditional logistic regression, adjusting for matching factors. Findings From Oct 24, 2012, to March 9, 2014, 114 eligible individuals presented with acute watery diarrhoea and were enrolled, 25 of whom were subsequently excluded. 47 participants were analysed as cases in the vaccine eff ectiveness case-control study and 42 as cases in the bias-indicator study. 33 (70%) of 47 cholera cases self-reported vaccination versus 167 (89%) of 188 controls (vaccine eff ectiveness 63%, 95% CI 8–85). 27 (57%) of 47 cases had certifi ed vaccination versus 147 (78%) of 188 controls (vaccine eff ectiveness 58%, 13–80). Neither self-reported nor verifi ed vaccination was signifi cantly associated with non-cholera diarrhoea (vaccine eff ectiveness 18%, 95% CI –208 to 78 by self-report and –21%, –238 to 57 by verifi ed vaccination). Interpretation Bivalent whole-cell oral cholera vaccine eff ectively protected against cholera in Haiti from 4 months to 24 months after vaccination. Vaccination is an important component of eff orts to control cholera epidemics

    Air quality and health implications of 1.5–2°C climate pathways under considerations of ageing population: A multi-model scenario analysis

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    Low-carbon pathways consistent with the 2°C and 1.5°C long-term climate goals defined in the Paris Agreement are likely to induce substantial co-benefits for air pollution and associated health impacts. In this analysis, using five global integrated assessment models, we quantify the emission reductions in key air pollutants resulting from the decarbonization of energy systems and the resulting changes in premature mortality attributed to the exposure to ambient concentrations of fine particulate matter. The emission reductions differ by sectors. Sulfur emissions are mainly reduced from power plants and industry, cuts in nitrogen oxides are dominated by the transport sector, and the largest abatement of primary fine particles is achieved in the residential sector. The analysis also shows that health benefits are the largest when policies addressing climate change mitigation and stringent air pollution controls are coordinated. We decompose the key factors that determine the extent of health co-benefits, focusing on Asia: changes in emissions, urbanization rates, population growth and ageing. Demographic processes, particularly due to ageing population, counteract in many regions the mortality reductions realized through lower emissions

    Tuning Reactivity and Electronic Properties through Ligand Reorganization within a Cerium Heterobimetallic Framework

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    Quantifying the impacts of shipping NOₓ emissions on tropospheric O₃, CH₄ and their radiative forcing

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    International shipping is a cornerstone of the global economy since it carries about 80% of the world trade by volume. It is also a growing sector that releases significant amounts of pollutants into the atmosphere. Shipping NOx emissions could represent about 15% of the total anthropogenic NOx emitted in 2000 and are particularly important since they perturb the concentrations of O3 and CH4, two greenhouse gases present in the atmosphere. Studies focusing on the impacts of shipping NOx emissions on tropospheric chemistry and radiative forcing remain however quite recent and still bear significant uncertainties. The aim of this study is to provide an extended view of the problem by making use of a state-of-art global chemistry-transport model (MOZART-4) in conjunction with a radiative transfer model (Edwards-Slingo). Since MOZART-4 has never been used before to analyse shipping NOx impacts, a thorough comparison with the material reported in previous studies was carried out. The global model was further tested by performing a sensitivity analysis of shipping perturbations against various uncertainties in atmospheric processes and model changes. In addition, impacts from the implementation of a ship plume parameterisation based on the concept of effective reaction rates were assessed. The O3 and CH4 radiative forcings resulting from shipping NOx emissions were then estimated with the help of Edwards-Slingo in 2000 and in the future by using the RCP scenarios. This last step laid the ground for a linearization of the global shipping NOx-O3-CH4 system. The assessment of MOZART-4 revealed that the model is suitable for the analysis of shipping NOx impacts. Although it simulates larger O3 perturbations in the free troposphere as well as a larger CH4 lifetime perturbation, estimates remain within 1-σ standard deviation of the results reported in a previous multimodel study. Current uncertainties in shipping emissions and particularly their magnitude remain the largest contributor to the uncertainty in shipping O3 and CH4 perturbations ([-39%, 67%] and [-37%, 59%], respectively). The shipping emission parameterisation developed by Dr. Huszar was found to be unsuitable for usage in MOZART-4, partly because of the absence of NOx sink processes. This was corrected by implementing the approach designed by Dr. Moldanova which lead to NOx and O3 reductions larger than 20% at the surface of the oceans. A net radiative forcing from shipping NOx emissions of -60 mW/m2 was computed with Edwards-Slingo in 2000. Under the RCP scenarios, the net radiative forcing range between -96 mW/m2 and -15 mW/m2. A linear relationship was finally derived between shipping NOx emissions and the radiative forcing of shipping O3 and CH4. Estimates calculated with the linear model remain within 15% of the values computed with the global models. Further work should focus on trying to reduce the uncertainties linked to the magnitude and spatial distribution of shipping emissions. The shipping emission parameterisation based on the concept of effective reaction rates still bear problems which should be addressed in the future. Finally, it would be interesting to estimate the future radiative forcings from shipping NOx emissions under the SRES scenarios since these forecast values are larger shipping emissions. This would potentially increase the robustness of the linear model
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