Estimation de la recharge de la nappe phréatique du Continental Terminal (Niamey, Niger) à partir des teneurs en tritium

Dans l'environnement typiquement sahélien de la région de Niamey, la réalimentation de la nappe phréatique du Continental Terminal est essentiellement due à l'infiltration de la pluie concentrée dans les mares endoréiques temporaires. Les teneurs en tritium sont un bon indicateur de l'intensité de la recharge. Un modèle simple utilise une chronique reconstituée des teneurs de la pluie à Niamey depuis 40 ans et fournit les taux de renouvellement correspondant aux valeurs mesurées dans la nappe (25 mm/an). Ces résultats sont cohérents avec ceux de l'approche hydrodynamique. (Résumé d'auteur

CAR-associated vesicular transport of an adenovirus in motor neuron axons.

Axonal transport is responsible for the movement of signals and cargo between nerve termini and cell bodies. Pathogens also exploit this pathway to enter and exit the central nervous system. In this study, we characterised the binding, endocytosis and axonal transport of an adenovirus (CAV-2) that preferentially infects neurons. Using biochemical, cell biology, genetic, ultrastructural and live-cell imaging approaches, we show that interaction with the neuronal membrane correlates with coxsackievirus and adenovirus receptor (CAR) surface expression, followed by endocytosis involving clathrin. In axons, long-range CAV-2 motility was bidirectional with a bias for retrograde transport in nonacidic Rab7-positive organelles. Unexpectedly, we found that CAR was associated with CAV-2 vesicles that also transported cargo as functionally distinct as tetanus toxin, neurotrophins, and their receptors. These results suggest that a single axonal transport carrier is capable of transporting functionally distinct cargoes that target different membrane compartments in the soma. We propose that CAV-2 transport is dictated by an innate trafficking of CAR, suggesting an unsuspected function for this adhesion protein during neuronal homeostasis

Caractérisation des échanges entre karst et rivière par imagerie infra-rouge thermique (IRT) aéroportée

International audienc

36Cl deposition rate reconstruction from bomb pulse until present: A study basedon groundwater records.

International audienc