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Impact of a community-based intervention on Aedes aegypti and its spatial distribution in Ouagadougou, Burkina Faso
No full textBackground Several studies highlighted the impact of community-based interventions whose purpose was to reduce the vectors' breeding sites. These strategies are particularly interesting in low-and-middle-income countries which may find it difficult to sustainably assume the cost of insecticide-based interventions. In this case study we determine the spatial distribution of a community-based intervention for dengue vector control using different entomological indices. The objective was to evaluate locally where the intervention was most effective, using spatial analysis methods that are too often neglected in impact assessments. Methods Two neighbourhoods, Tampouy and Juvenat in Ouagadougou, Burkina Faso, were chosen among five after a survey was conducted, as part of an assessment related to the burden of dengue. As part of the community-based intervention conducted in Tampouy between August and early October 2016, an entomological survey was implemented in two phases. The first phase consisted of a baseline entomological characterization of potential breeding sites in the neighbourhood of Tampouy as well as in Juvenat, the control area. This phase was conducted in October 2015 at the end of the rainy season. The mosquito breeding sites were screened in randomly selected houses: 206 in Tampouy and 203 in Juvenat. A second phase took place after the intervention, in October 2016. The mosquito breeding sites were investigated in the same yards as during the baseline phase. We performed several entomological analyses to measure site productivity as well as before and after analysis using multilevel linear regression. We used Local Indicators of Spatial Association (LISAs) to analyse spatial concentrations of larvae. Results After the intervention, it is noted that LISAs at Tampouy reveal few aggregates of all types and the suppression of those existing before the intervention. The analysis therefore reveals that the intervention made it possible to reduce the number of concentration areas of high and low values of pupae. Conclusions The contribution of spatial methods for assessing community-based intervention are relevant for monitoring at local levels as a complement to epidemiological analyses conducted within neighbourhoods. They are useful, therefore, not only for assessment but also for establishing interventions. This study shows that spatial analyses also have their place in population health intervention research
Mieux comprendre les défis de la médicalisation de la prévention du VIH en France : la prophylaxie préexposition au prisme des sciences sociales
No full textSeasonal variation of giant gourami ( Osphronemus goramy ) spawning activity and egg production in aquaculture ponds
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Maize, sorghum, and pearl millet have highly contrasting species strategies to adapt to water stress and climate change-like conditions
No full textThis study compared maize, sorghum and pearl-millet, leading C-4 cereals, for the transpiration rate (TR) response to increasing atmospheric and soil water stress. The TR response to transiently increasing VPD (0.9-4.1 kPa) and the transpiration and leaf area expansion response to progressive soil drying were measured in controlled conditions at early vegetative stage in 10-16 genotypes of each species grown in moderate or high vapor pressure deficit (VPD) conditions. Maize grown under moderate VPD conditions restricted TR under high VPD, but not sorghum and pearl millet. By contrast, when grown under high VPD, all species increased TR upon increasing VPD, suggesting a loss of TR responsiveness. Sorghum and pearl-millet grown under high VPD reduced leaf area, but not maize. Upon progressive soil drying, maize reduced transpiration at higher soil moisture than sorghum and pearl millet, especially under high VPD, and leaf area expansion declined at similar or lower soil moisture than transpiration in maize and sorghum. It is concluded that maize conserves water by restricting transpiration upon increasing VPD and under higher soil moisture than sorghum and millet, giving maize significantly higher TE, whereas sorghum and pearl millet rely mostly on reduced leaf area and somewhat on transpiration restriction
Distinct and combined impacts of climate and land use scenarios on water availability and sediment loads for a water supply reservoir in northern Morocco [+ Corrigendum 2021, 9, 166]
No full textThe objective of this study was to examine the impacts of climate and land use changes on water availability and sediment loads for a water supply reservoir in northern Morocco using data-intensive simulation models in a data-scarce region. Impacts were assessed by comparing the simulated water and sediment entering the reservoir between the future period 2031-2050 and the 1983-2010 reference period. Three scenarios of land use change and two scenarios of climate change were developed in the Tleta watershed. Simulations under current and future conditions were performed using the Soil and Water Assessment Tool (SWAT) model. The simulations showed that climate change will lead to a significant decrease in the annual water supply to the reservoir (-16.9% and -27.5%) and in the annual volume of sediment entering the reservoir (-7.4% and -12.6%), depending on the climate change scenarios tested. The three scenarios of land use change will lead to a moderate change in annual water inflow into the reservoir (between -6.7% and -6.2%), while causing a significant decrease in sediment entering the reservoir (-37% to -24%). The combined impacts of climate and land use changes will cause a reduction in annual water availability (-9.9% to -33.3%) and sediment supplies (-28.7% to -45.8%). As a result, the lifetime of the reservoir will be extended, but at the same time, the risk of water shortages will increase, especially from July to March. Therefore, alternative water resources must be considered
The negative self-perceived health of migrants with precarious status in Montreal, Canada : a cross-sectional study
No full textBackground Knowledge about the health impacts of the absence of health insurance for migrants with precarious status (MPS) in Canada is scarce. MPS refer to immigrants with authorized but temporary legal status (i.e. temporary foreign workers, visitors, international students) and/or unauthorized status (out of legal status, i.e. undocumented). This is the first large empirical study that examines the social determinants of self-perceived health of MPS who are uninsured and residing in Montreal. Methods and findings Between June 2016 and September 2017, we performed a cross-sectional survey of uninsured migrants in Montreal, Quebec. Migrants without health insurance (18+) were sampled through venue-based recruitment, snowball strategy and media announcements. A questionnaire focusing on sociodemographic, socioeconomic and psychosocial characteristics, social determinants, health needs and access to health care, and health self-perception was administered to 806 individuals: 54.1% were recruited in urban spaces and 45.9% in a health clinic. 53.9% were categorized as having temporary legal status in Canada and 46% were without authorized status. Regions of birth were: Asia (5.2%), Caribbean (13.8%), Europe (7.3%), Latin America (35.8%), Middle East (21%), Sub-Saharan Africa (15.8%) and the United States (1.1%). The median age was 37 years (range:18-87). The proportion of respondents reporting negative (bad/fair) self-perception of health was 44.8%: 36.1% among migrants with authorized legal status and 54.4% among those with unauthorized status (statistically significant difference; p<0.001). Factors associated with negative self-perceived health were assessed using logistic regression. Those who were more likely to perceive their health as negative were those: with no diploma/primary/secondary education (age-adjusted odds ratio [AOR]: 2.49 [95% CI 1.53-4.07, p<0.001] or with a college diploma (AOR: 2.41 [95% CI 1.38-4.20, p = 0.002); whose family income met their needs not at all/a little (AOR: 6.22 [95% CI 1.62-23.85], p = 0.008) or met their needs fairly (AOR: 4.70 [95% CI 1.21-18.27], p = 0.025); with no one whom they could ask for money (AOR: 1.60 [95% CI 1.05-2.46], p = 0.03); with perception of racism (AOR: 1.58 [95% CI 1.01-2.48], p = 0.045); with a feeling of psychological distress (AOR: 2.17 [95% CI 1.36-3.45], p = 0.001); with unmet health care needs (AOR: 3.45 [95% CI 2.05-5.82], p<0.001); or with a health issue in the past 12 months (AOR: 3.44 [95% CI 1.79-6.61], p<0.001). Some variables that are associated with negative self-perceived health varied according to gender: region of birth, lower formal education, having a family income that does not meet needs perfectly/very well, insalubrious housing, not knowing someone who could be asked for money, and having ever received a medical diagnosis. Conclusions In our study, almost half of immigrants without health insurance perceived their health as negative, much higher than reports of negative self-perceived health in previous Canadian studies (8.5% among recent immigrants, 19.8% among long-term immigrants, and 10.6% among Canadian-born). Our study also suggests a high rate of unmet health care needs among migrants with precarious status, a situation that is correlated with poor self-perceived health. There is a need to put social policies in place to secure access to resources, health care and social services for all migrants, with or without authorized status
Quantifying the benefits of nonlinear methods for global statistical hindcasts of tropical cyclones intensity
No full textWhile tropical cyclone (TC) track forecasts have become increasingly accurate over recent decades, intensity forecasts from both numerical models and statistical schemes have been trailing behind. Most operational statistical-dynamical forecasts of TC intensity use linear regression to relate the initial TC characteristics and most relevant large-scale environmental parameters along the TC track to the TC intensification rate. Yet, many physical processes involved in TC intensification are nonlinear, hence potentially hindering the skill of those linear schemes. Here, we develop two nonlinear TC intensity hindcast schemes, for the first time globally. These schemes are based on either support vector machine (SVM) or artificial neural network (ANN) algorithms. Contrary to linear schemes, which perform slightly better when trained individually over each TC basin, nonlinear methods perform best when trained globally. Globally trained nonlinear schemes improve TC intensity hindcasts relative to regionally trained linear schemes in all TC-prone basins, especially the SVM scheme for which this improvement reaches similar to 10% globally. The SVM scheme, in particular, partially corrects the tendency of the linear scheme to underperform for moderate intensity (category 2 and less on the Saffir-Simpson scale) and decaying TCs. Although the TC intensity hindcast skill improvements described above are an upper limit of what could be achieved operationally (when using forecasted TC tracks and environmental parameters), it is comparable to that achieved by operational forecasts over the last 20 years. This improvement is sufficiently large to motivate more testing of nonlinear methods for statistical TC intensity prediction at operational centers
An original urban land cover representation and its effects on rain event-based runoff and TSS modelling
No full textDuring rainfall events, a wide range of contaminants generated by urban areas are transferred into rivers. Modelling tools are increasingly required by decision makers to assess the effects of urban development and mitigation measures on urban runoff quality. However, representing the spatial heterogeneity of urban land cover in water quality modelling is a real challenge. This study presents a methodology to analyze and characterize the land cover of an urban catchment within a water quality model. The application site is the urban river Verdanson located in Montpellier city (France), where the climate is Mediterranean. Firstly, a time effective original method of identifying homogeneous urban surfaces in terms of build-up/wash-off processes from an existing land-use map and aerial photo interpretation is presented. Secondly, the sensitivity of model outputs to the discretization of a catchment into homogeneous land cover types, called Water quality Response Units (WQRUs), is tested. The results reveal that discretizing the catchment into WQRUs enhances the relevance of hydrological outputs and provide more flexibility for a calibration of Total Suspended Solids wash-off parameters. The findings open interesting opportunities to integrate catchment-scale land cover data into the modelling of wash-off processes and allow urban runoff managers to assess the influence of urban land use planning scenarios on water quality
