Protecting environmental flows to achieve long-term water security.

In this work, we propose a new approach to diagnose if a water allocation scheme is compatible with long-term water security at the catchment scale, and suggest steps to achieve such compatibility. We argue that when the remaining flow of a river after upstream withdrawals is not sufficient to safeguarding ecological river functions, the basin is at extreme risk of water scarcity, which indicates that the water management is failing. To test this, we analysed the water scarcity risks and the safeguarded environmental flows (e-flows) in 277 basins across a wide range of hydro-climatic conditions in Chile (17-55°S). For each basin, water scarcity risks were assessed based on water stress indices (WSIs, computed as the ratio of withdrawals to water availability), considering two water-use scenarios: (i) WSImax, where total withdrawals correspond to the maximum consumptive water allowed by the law, i.e., where only the e-flows protected by law remain in the river, and (ii) WSIalloc, where total withdrawals correspond to the actual allocated consumptive water uses within the basins. Further, we evaluated the adequacy of the water management system to protect ecological river functions by contrasting the e-flows protected in Chile with those safeguarded in six other countries. The water allocation system in Chile incorporated the protection of minimum e-flows in 2005 and established that these do not exceed 20% of the mean annual streamflow, except in some exceptional cases. This upper limit is consistently lower than the e-flows safeguarded in other countries, where 20%-80% of the mean annual streamflow are protected. This turns out in WSImax values between 80% and 100% in all basins, well above the threshold associated with over-committed basins under extreme risk of water scarcity (70% typically). When moving from the legally allowed to the actually allocated water use scenario, we found contrasting results: about 70% of the basins show low water scarcity risk (WSIalloc <40%), while an 18% have WSIalloc above 100%, indicating the allocation is going beyond current law limits and even beyond physical limits. Our results reveal that the link between e-flows, water allocation and water security has not been adequately incorporated in the current law. E-flows stipulated by law are insufficient to fulfil environmental requirements, while placing the basins under extreme risk of water scarcity if the total allowed withdrawals were exerted. To move towards a system that can effectively achieve long-term water security, we recommend: (i) To define tolerable water scarcity risks for basins, considering environmental requirements. (ii) To translate those risks into measurable basin indices to measure water security, such as the WSI. (iii) To set maximum water use limits (or minimum e-flows) within the basins that are compatible to the water security goals. If, under current and projected water availability conditions, the existing withdrawals exceed these limits, water managers should be able to adapt total consumption to the required limits.

[A comparative cost analysis of single-use versus reusable fiberoptic bronchoscopes: Is single-use fiberscope worth it?] / Analyse comparative de coût entre les fibroscopes bronchiques à usage unique et réutilisables : le fibroscope à usage unique, est-ce que ça vaut le coût ?

OBJECTIVE: To present a minimization-cost analysis to compare reusable and single-use fiberscopes in a French health institution. MATERIALS AND METHODS: The amortization cost assessment has been achieved over a period of five years, and took into account the acquisition and maintenance costs, as well as the costs related to disinfection of reusable fiberscopes. The cost of single-use fiberscopes was calculated according to its acquisition and elimination costs. Finally, we compared the costs of single-use vs. reusable use during nights, weekends and days off to estimate the additional cost of the referencing of single-use fiberscopes for theses specific periods. RESULTS: The total cost of reusable fiberscopes was 62,511 € including VAT over 5 years whereas the cost of single-use fiberscope was 79,200 € including VAT over 5 years. The total cost of single-use fiberscopes if utilized during nights, weekends and days off was estimated to 19,800 € including VAT over 5 years, with an estimated activity at 15 intubations per year. Conversely, the cost of the utilization of reusable fiberscopes during nights, weekends and days off was estimate to 13,075 € including VAT over 5 years. CONCLUSION: This study shows that the utilization costs of single use and reusable fiberscopes are very close. But because of the benefits of single-use fiberscopes and according to current recommendations, we consider to acquire single-use fiberscope especially for emergencies such as difficult tracheal intubation and for restrictive periods (nights, weekends and day off).

Reduction of low temperature engine pollutants by understanding the exhaust species interactions in a diesel oxidation catalyst.

The interactions between exhaust gas species and their effect (promotion or inhibition) on the light-off and activity of a diesel oxidation catalyst (DOC) for the removal of pollutants are studied, using actual engine exhaust gases from the combustion of diesel, alternative fuels (rapeseed methyl ester and gas-to-liquid fuel) and diesel/propane dual fuel combustion. The activity of the catalyst was recorded during a heating temperature ramp where carbon monoxide (CO) and hydrocarbon (HC) light-off curves were obtained. From the catalyst activity tests, it was found that the presence of species including CO, medium-heavy HC, alkenes, alkanes, and NOx and their concentration influence the catalyst ability to reduce CO and total HC emissions before release to the atmosphere. CO could inhibit itself and other species oxidation (e.g., light and medium-heavy hydrocarbons) while suffering from competitive adsorption with NO. Hydrocarbon species were also found to inhibit their own oxidation as well as CO through adsorption competition. On the other hand, NO2 was found to promote low temperature HC oxidation through its partial reduction, forming NO. The understanding of these exhaust species interactions within the DOC could aid the design of an efficient aftertreatment system for the removal of diesel exhaust pollutants.