The dynamics of water content in the superficial layers of soils is critical in the modelling of land-surface processes. In arid regions, vapour flux contributes significantly to the global water mass balance. To account for it in theoretical descriptions, most of the models proposed in the literature rely on the local equilibrium assumption that constrains the vapour pressure to remain at its equilibrium value. It implicitly amounts to consider an instantaneous phase change. Recent works underlined a retardation time and a decrease in phase change rate as the water content gets lower. Therefore, the objective is to revisit water transport modelling by rejecting the local equilibrium assumption. This requires developing a non-equilibrium model by taking into account the phase change kinetics. To assess the interest of this approach, a natural soil of Burkina-Faso has been experimentally characterized from independent tests and soil column experiments have been carried out. The comparison of experimental drying kinetics and water content pro
This is a case-control study conducted to examine the risk factors for multidrug resistance (MDR) among patients with pulmonary tuberculosis (TB) in four centers in Burkina Faso, West Africa: Ouagadougou, Bobo-Dioulasso, Gorom-Gorom, and Dori. Fifty-six MDR-TB cases and 304 controls were enrolled of which 40 MDR-TB cases and 222 controls were from Ouagadougou. The majority of cases were male, with 39 among MDR-TB cases and 205 in controls. The MDR-TB cases were aged from 14 to 75 years versus 11 to 75 years in the controls. The total risk assessment battery score was 11. Living outside of Burkina Faso (adjusted odds ratio [OR] = 0.017; 95% confidence interval [95% CI]: 0.001-0.325), known TB contact (OR = 0.045; 95% CI: 0.004-0.543), and patients with previous history of TB treatment (OR = 0.004; 95% CI: 0.000-0.0.052) were significantly associated with MDR-TB. TB contact and mainly previous treatment were the strongest determinants of MDR-TB. Also, living outside Burkina was a risk factor.
Improved access to water is a key factor in reducing diarrhoeal diseases, a leading cause of death among children in sub-Saharan Africa. In terms of water access, sub-Saharan African cities are some of the worst off in the world, with 20% of populations supplied by an unimproved water source. This situation is even worse in informal settlement areas. Using cross-sectional data on access to water from a survey implemented in three informal neighbourhoods of the Ouagadougou Health and Demographic Surveillance System, logistic regressions are modelled to test the effect of different modalities of access to water on childhood diarrhoea. Our results show that the prevalence of diarrhoea in children is high: one-third of households with a child under 10 experienced an episode of childhood diarrhoea during the 2 weeks preceding the survey, even though 91% of the households surveyed have access to an improved water source. The results show that efforts to reduce childhood morbidity would be greatly enhanced by strengthening piped water access in informal settlement areas in Africa. In addition, this study confirms that, beyond the single measure of the main access to water, accurate variables that assess the accessibility to water are needed.
By focusing on what can be observed by running traceroute-like measurements at a high frequency from a single monitor to a fixed destination set, we show that the observed view of the topology is constantly evolving at a pace much higher than expected. Repeated measurements discover new IP addresses at a constant rate, for long period of times (up to several months).In order to provide explanations, we study this phenomenon both at the IP, and at the Autonomous System levels. We show that this renewal of IP addresses is partially caused by a BGP routing dynamics, altering paths between existing ASes. Furthermore, we conjecture that an intra AS routing dynamics is another cause of this phenomenon.
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