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Estuary sedimentary sequences have been the focus of several papers in the last decades; however, the majority these papers were centered in mesotidal and macrotidal estuaries of the middle latitudes. This present paper studies, from a sedimentological point of view, the infilling of a microtidal, wave-dominated tropical estuary, where wide tidal flats, mangroves and sabkhas are developed. Somone Lagoon is a Senegalese protected environment, very rich from an ecological point of view and with a definitive touristic vocation. For this work, 14 piston cores were studied. Additionally, the grain size, calcium carbonate and organic matter contents of 61 sediment samples vertically distributed in these cores were analyzed. The distribution of facies and the vertical sequences of sediments show the influence of the tropical seasonal fluctuations of fluvial sediment supply and evaporation processes. A high degree of bioturbation and an elevated organic content can be interpreted as the result of a high capacity of retention of the organic material into the estuary influenced by the weak tidal currents typical of a microtidal regime. These processes, acting since the last Holocene invasion of sea level, caused an advanced state of infilling of this estuarine system where both flood tidal deltas and bay head deltas prograde above the fine facies of the central domain of the estuary.

Navel 2 est un site de production du fer et d’habitat. Son étude vise une mise en valeur du savoir-faire des communautés précoloniales de Matam. L’envahissement de cette ville par la France, en 1857, a entraîné un oubli progressif du passé des peuples autochtones dont l’histoire est connue qu’à travers la tradition orale. Aujourd’hui, l’archéologie de ce site certifie que ce complexe a accueilli, avant la colonisation, des populations disposant de compétences diverses notamment dans l’art de la production du fer.

Developing countries frequently see their currency depreciated to varying degrees. The consequences of such monetary disturbances on the nutrition of young children are not well known, though children are the most vulnerable in nutritional terms. One year after the 50% devaluation of the CFA Franc (communauté financière africaine, "African Financial Community"), which took place on 12 January 1994 simultaneously in fourteen countries, nine of which are on the UNDP list of least developed countries, we wanted to find out the long-term effects of the devaluation, and the strategies that families had adopted to cope with it. In Brazzaville, Congo, in December 1994, an epidemiological survey was conducted on a representative sample of 893 children between the ages of 4 and 12 months in two districts, and indicators of child nutrition were established. A comparable survey had been conducted in December 1993, before the devaluation. In Senegal, in the absence of a previous survey which could be used in comparison, a qualitative survey using RAP methodology, was conducted in January 1995 in two towns near the capital. In three districts in each of these towns, a cluster of ten plots was chosen at random and surveyed, with a combination of semi-structured individual interviews with mothers (n = 60) and group interviews with all the women together (n = 6). The information was put together with interviews of 25 local traders selling food. In the Congo, comparison of the two surveys shows that the practice of breast-feeding had hardly changed, nor had the age at which baby food was introduced (90% of children of 4-5 months take semi-solid and solid foods); on the other hand, more children are being given the ordinary family meal earlier, at 6-9 months. The proportion of baby foods based on commercially imported flour has fallen (from 32% in 1993 to 18% in 1994), and has been replaced with local products based on maize; this change is more marked among poorer families. The low nutritional value of such preparations is in part compensated by the addition of sugar, though less milk is added (28% in 1994 as opposed to 43% in 1993). In Senegal, mothers do not seem to have changed their breast-feeding practices either, the age at which baby foods are introduced, or the number of times they are provided daily. The most important change is the drop in quality of food given to children, and the poorer family food for the older children. The partial switch from imported products to local produce was an expected consequence of devaluation; it is clearly confirmed here for nutrition of young children, with the consequent loss of nutritional quality (a reduction in energy density and in nutrients). The first thing needed is, therefore, an improvement in local manufacture of food supplements of good nutritional quality, for young children. Mothers also complain of the increased difficulty in managing a family diet so as to take account of economic needs, cultural values and nutrition. They therefore criticize a number of nutritional education messages that are clearly no longer appropriate to the new economic context. Finally the fact that young children are getting poorer quality nutrition is worrying for the future: if it lasts, the nutritional status of children will deteriorate; whenever possible, monitoring must be established so that measures can be taken when necessary to forestall any dramatic deterioration that would endanger the health of the children.

Differential centrifugation and isopycnic equilibration in density gradients were used to localize glutathione (GSH), glutathione peroxidase and glutathione reductase in the subcellular organelles of WI-38 fibroblasts. GSH was present in all the subcellular fractions, whereas the glutathione peroxidase and reductase activities were restrained to the cytoplasm and the mitochondrial fractions. After equilibration in density gradients, the results showed the presence of GSH, glutathione peroxidase and glutathione reductase in both the cytoplasm and mitochondria. GSH was also located in plasma membranes and probably in peroxisomes, endoplasmic reticulum and lysosomal membranes. Evolution of GSH in ageing fibroblasts showed a sudden increase of its concentration just before cell death. The glutathione peroxidase activity already decreases in the early passages, while the decrease of the glutathione reductase activity was constant and reached a drastic low level at the end of the culture. In conclusion, GSH is probably involved in the cell degeneration associated with ageing but because of its multiple functions and its ubiquitous localization, it is difficult to assert to which extent this metabolite is implicated in the ageing process.