Jets and Topography: Jet Transitions and the Impact on Transport in the Antarctic Circumpolar Current

The Southern Ocean’s Antarctic Circumpolar Current (ACC) naturally lends itself to interpretations using a zonally averaged framework. Yet, navigation around steep and complicated bathymetric obstacles suggests that local dynamics may be far removed from those described by zonally symmetric models. In this study, both observational and numerical results indicate that zonal asymmetries, in the form of topography, impact global flow structure and transport properties. The conclusions are based on a suite of more than 1.5 million virtual drifter trajectories advected using a satellite altimetry–derived surface velocity field spanning 17 years. The focus is on sites of “cross front” transport as defined by movement across selected sea surface height contours that correspond to jets along most of the ACC. Cross-front exchange is localized in the lee of bathymetric features with more than 75% of crossing events occurring in regions corresponding to only 20% of the ACC’s zonal extent. These observations motivate a series of numerical experiments using a two-layer quasigeostrophic model with simple, zonally asymmetric topography, which often produces transitions in the front structure along the channel. Significantly, regimes occur where the equilibrated number of coherent jets is a function of longitude and transport barriers are not periodic. Jet reorganization is carried out by eddy flux divergences acting to both accelerate and decelerate the mean flow of the jets. Eddy kinetic energy is amplified downstream of topography due to increased baroclinicity related to topographic steering. The combination of high eddy kinetic energy and recirculation features enhances particle exchange. These results stress the complications in developing consistent circumpolar definitions of the ACC fronts

Socio-economic study of the Uganda coffee chain

Objectives: The general objectives of the study were to: Analyse the structure of the commodity chain and the potential consequences of OTA standards on the coffee commodity chain Study the feasibility of technological alternatives investigated by research and the project for reducing contamination risks

Richesse et diversité

Peuples de la forêt, des savanes, du Sahel, des montagnes, peuples animistes ou islamisés, ayant parfois adopté le christianisme, organisations sociales diversifiées à l’extrême, barrières linguistiques et dialectes innombrables, l’Afrique noire demeure un terrain privilégié pour l’anthropologie. L’émiettement ethnique qui caractérise la plupart de ses Etats contemporains, loin d’être un signe d’immaturité politique, doit être reconnu comme la marque d’une richesse culturelle encore vivace. D..

Si loin, si proches de la prison : les centres éducatifs fermés pour jeunes délinquants

La création des premiers Centres éducatifs fermés (CEF), en septembre 2002, fut l’un des symboles les plus marquants d’un processus de durcissement des réponses pénales apportées aux jeunes délinquants. Fondé sur une enquête monographique au sein d’un CEF de la Protection judiciaire de la jeunesse (PJJ), cet article analyse les rapports ambigus qu’entretiennent ces nouveaux établissements à « l’enfermement », et plus généralement à la prison. Nos observations montrent en effet que le fonctionnement quotidien du CEF, malgré la philosophie du contrôle qui le structure, n’exclut pas toute possibilité de sortie, autorisée ou non : les CEF apparaissent comme des centres éducatifs « fermés-ouverts » plus que strictement « fermés ». Nos observations montrent cependant, dans le même temps, que les stratégies éducatives élaborées par les éducateurs autour des contraintes – en particulier les contraintes pénales – qui pèsent sur les jeunes placés sont toujours susceptibles de faire des CEF une antichambre de la prison, brouillant les frontières entre « milieu ouvert » et « milieu fermé ».The opening of the first closed educational centres (CEF) in France in September 2002 was one of the most striking symbols of a crackdown on juvenile delinquents. Based on a monographic survey within a CEF run by the public sector of the Youth Judicial Protection Service (PJJ), this article analyses the ambiguous relationship that these new institutions have with “confinement” and prison in general. Our observations show that despite the philosophy of control that structures the CEF, its day-to-day operations do not rule out the possibility of temporary release, whether authorised or not: CEFs appear to be “open-closed” more than completely “closed” educational centres. At the same time, our observations show that educational strategies designed by educators around the constraints—especially the legal constraints—faced by the youths in their charge are still likely to make CEFs an antechamber of prison, blurring the boundaries between “open custody” and “closed custody”