Evolution de la ressource en eau dans la vallée du Merguellil (Tunisie centrale)

International audienceLa plaine de Kairouan (Tunisie centrale) se trouve au débouché des trois grandes vallées du Zéroud, du Merguellil et du Nebhana. Dans ce contexte semi-aride (pluies moyennes entre 200 et 400 mm.an−1), l'intensification de l'irrigation au cours des dernières décennies a suscité une forte croissance de la demande en eau. En même temps, différents aménagements affectent l'ensemble du fonctionnement hydrologique : multiples ouvrages de conservation des eaux et des sols, petits et moyens, d'une part, grands barrages de protection contre les crues sur les trois oueds majeurs d'autre part. La distribution de l'eau B la surface du bassin-versant et dans le sous-sol a donc considérablement évolué et change encore. Dans la plaine du Merguellil, à l'aval du barrage el Haouareb, la nappe alluviale quaternaire est devenue la seule ressource en eau disponible. Elle est actuellement exploitée sans réel contrôle, ce qui conduit à une baisse sensible de son niveau (de 0,25 à 1 m par an). Elle n'est plus alimentée comme en régime naturel par les crues de l'oued, désormais entièrement bloquées par le barrage. Elle ne reçoit plus que les apports des nappes latérales et le flux souterrain passant sous le barrage. L'avenir du développement agricole régional dépend de manière évidente de la maîtrise de la ressource souterraine et donc de sa bonne connaissance. Malgré de multiples mesures de terrain et études entreprises depuis plusieurs décennies, il reste encore de nombreuses incertitudes qui rendent le bilan actuel de la nappe très incertain, à la fois sur les flux entrants et sortants. La surexploitation est nette et générale et aucune solution alternative simple n'apparaît. Le risque d'augmentation à long terme de la minéralisation existe mais ce problème est moins grave et moins immédiat que la baisse piézométrique

Atomic motions in the αβ\alpha\beta-region of glass-forming polymers: Molecular versus Mode Coupling Theory approach

We present fully atomistic Molecular Dynamics simulation results on a main-chain polymer, 1,4-Polybutadiene, in the merging region of the $\alpha$- and $beta$-relaxations. A real space analysis reveals the occurrence of localized motions (``$\beta$-like'') in addition to the diffusive structural relaxation. A molecular approach provides a direct connection between the local conformational changes reflected in the atomic motions and the secondary relaxations in this polymer. Such local processes occur just in the time window where the $\beta$-process of the Mode Coupling Theory is expected. We show that the application of this theory is still possible, and yields an unusually large value of the exponent parameter. This result might originate from the competition between two mechanisms for dynamic arrest: intermolecular packing and intramolecular barriers for local conformational changes (``$\beta$-like'').Comment: 10 pages, 6 figure

Design, Synthesis and Discovery of N,N'-Carbazoyl-aryl-urea Inhibitors of Zika NS5 Methyltransferase and Virus Replication

The recent outbreaks of Zika virus (ZIKV) infection worldwide make the discovery of novel antivirals against flaviviruses a research priority. This work describes the identification of novel inhibitors of ZIKV through a structure‐based virtual screening approach using the ZIKV NS5‐MTase. A novel series of molecules with a carbazoyl‐aryl‐urea structure has been discovered and a library of analogues has been synthesized. The new compounds inhibit ZIKV MTase with IC50 between 23–48 μM. In addition, carbazoyl‐aryl‐ureas also proved to inhibit ZIKV replication activity at micromolar concentration

Влияние ионной бомбардировки на формирование поверхностных слоев при азотировании в безводородной плазме газового разряда

В работе приведены результаты изучения процессов упрочнения стальных образцов в безводородной плазме низковольтного газового разряда в вакууме. В отличие от тлеющего разряда, широко применяемого в промышленных технологиях для проведения ионно-плазменного азотирования, в данном типе газового разряда из-за низкого давления заметно выражены эффекты распыления поверхности обрабатываемых деталей. Данное обстоятельство однозначно должно приводить к интенсификации диффузионных процессов. В работе описаны параметры оборудования, приводятся экспериментальные данные по измерениям шероховатости, микротвердости и структуре поверхностей легированных сталей. Отдельное внимание уделено вопросу азотирования закаленных сталей в данном типе разряда в диапазоне температур отпуска.In this work presents the results of studying the processes of hardening of steel samples in hydrogen-free plasma of low-voltage gas discharge in vacuum. In contrast to the glow discharge, widely used in industrial technologies for ion-plasma nitriding, in this type of gas discharge due to the low pressure, the effects of spraying the surface of the processed parts are markedly expressed. This fact should definitely lead to the intensification of diffusion processes. The paper describes the parameters of the equipment, provides experimental data on the measurements of roughness, microhardness and structure of the surfaces of alloy steels. Special attention is paid to the issue of nitriding of hardened steels in this type of discharge in the tempering temperature range

A physical activity intervention for children with type 1 diabetes- steps to active kids with diabetes (STAK-D): a feasibility study

Background This study describes the development and feasibility evaluation of a physical activity intervention for children with type 1 diabetes called ‘Steps to Active Kids with Diabetes’ (STAK-D). It aims to explore the feasibility and acceptability of the intervention and study design. Methods Thirteen children aged 9-11 years and their parents were recruited from one paediatric diabetes clinic. A process evaluation was conducted alongside a two-arm randomised feasibility trial, including assessment of rate of recruitment, adherence, retention, data completion and burden, implementation fidelity and adverse events. Qualitative interviews with children (n=9), parents (n=8), healthcare professionals (n=3) and STAK-D volunteers (n=8) explored intervention acceptability. Interviews were analysed thematically. Results Rate of recruitment was 25%, with 77% retention at 3-month follow-up. Study burden was low, data completion was high and the intervention was delivered as per protocol. No serious adverse event was reported. Engagement with intervention materials was generally good, but attendance at group activity sessions was low due to logistical barriers. Interview analysis identified preferred methods of recruitment, motivations for recruitment, barriers and facilitators to adherence, the experience of data collection, experience of the STAK-D programme and its perceived benefits. Conclusions STAK-D was feasible and acceptable to children, their parents and healthcare professionals, but group sessions may present logistical issues. Recruitment and retention may be improved with a clinic-wide approach to recruitment. Trial registration This trial was registered on ClinicalTrials.gov: NCT02144337 (16/01/2014). Keywords Children, feasibility study, intervention, paediatric diabetes, physical activity, process evaluation, self-efficacy, type 1 diabete