Quel avenir pour les systèmes oasiens au Sud du Sahara ? Situation actuelle, perspectives d'évolution, enjeux pour la recherche. Contribution au document de travail CIRAD-ORSTOM-SPAAR : Quelques réflexions à propos de l'intensification en Afrique de l'Ouest et du Centre

Les sytèmes oasiens, mis au point en Afrique au nord du Sahara depuis des siècles, peuvent constituer un modèle de développement pour des sociétés rurales au sud du Sahara. Les sécheresses récentes amènent les sociétés pastorales nord sahéliennes à assurer elles-mêmes une partie de leur subsistance en pratiquant une agriculture oasienne. Quelle est la situtation de l'agriculture d'oasis au sud du Sahara, quelles sont les perspectives d'évolution, quels enjeux son développement représente-t-il pour la recherche ? Ce document propose quelques options pour le développement d'une agriculture oasienne au sud du Sahara. (Résumé d'auteur

Vital software: Formal method and coded processor

International audienceSiemens Transportation Systems has been developing mass transit systems for 30 years and for more than 10 years it has used the B formal method to develop and validate its safety critical software. With B, the software is derived stepwise from an abstract mathematical specification and formal proof ensures that each intermediate step is equivalent to the previous one. With the Vital Coded Processor, any run time error caused either by a compiler error or a hardware failure is detected and the unit is set in a safe state. A high level of productivity is achieved through the use of a tool that derives semi-automatically the code from the formal specification

Design of a biologically inspired navigation system for the Psikharpax rodent robot

This work presents the development and implementation of a biologically inspired navigation system on the autonomous Psikharpax rodent robot. Our system comprises two independent navigation strategies: a taxon expert and a planning expert. The presented navigation system allows the robot to learn the optimal strategy in each situation, by relying upon a strategy selection mechanism

Pharmacological chaperone therapies: Can aldehyde dehydrogenase activator make us healthier?

Hom Santolaia, Cint

Mathematical modeling and numerical simulation of a bioreactor landfill using Feel++

In this paper, we propose a mathematical model to describe the functioning of a bioreactor landfill, that is a waste management facility in which biodegradable waste is used to generate methane. The simulation of a bioreactor landfill is a very complex multiphysics problem in which bacteria catalyze a chemical reaction that starting from organic carbon leads to the production of methane, carbon dioxide and water. The resulting model features a heat equation coupled with a non-linear reaction equation describing the chemical phenomena under analysis and several advection and advection-diffusion equations modeling multiphase flows inside a porous environment representing the biodegradable waste. A framework for the approximation of the model is implemented using Feel++, a C++ open-source library to solve Partial Differential Equations. Some heuristic considerations on the quantitative values of the parameters in the model are discussed and preliminary numerical simulations are presented

The plastic cellular states of liver cells: Are EpCAM and Lgr5 fit for purpose?

Adult liver cells have been considered restricted regarding their fate and lineage potential. That is, hepatocytes have been thought able only to generate hepatocytes and duct cells, only duct cells. While this may be the case for the majority of scenarios in a state of quiescence or homeostasis, evidence suggests that liver cells are capable of interconverting between cellular states of distinct phenotypic traits. This interconversion or plasticity had been suggested by classical studies using cellular markers, but recently lineage tracing approaches have proven that cells are highly plastic and retain an extraordinary ability to respond differently to normal tissue homeostasis, to tissue repair, or when challenged to expand ex vivo or to differentiate upon transplantation. Stemness, as "self-renewal and multipotency," seems not to be limited to a particular cell type but rather to a cellular state in which cells exhibit a high degree of plasticity and can move back and forth in different phenotypic states. For instance, upon damage cells can dedifferentiate to acquire stem cell potential that allows them to self-renew, repopulate a damaged tissue, and then undergo differentiation. In this review, we will discuss the evidence on cellular plasticity in the liver, focusing our attention on two markers, epithelial cell adhesion molecule and leucine-rich repeat-containing G protein-coupled receptor 5, which identify cells with stem cell potential. (Hepatology 2016;64:652-662).MH: is a Wellcome Trust Sir Henry Dale Fellow and is jointly funded by the Wellcome Trust and the Royal Society (104151/Z/14/Z); LD: is funded by the Interuniversity Attraction Poles (IAP) - phase VII - contract P7/47 (Federal Science Policy – BELSPO).This is the final version of the article. It first appeared from Wiley via https://doi.org/ 10.1002/hep.2846