This study examines energy expenditure and physical activity levels for a sample of 40 adolescent girls of the Sereer ethnic group of rural Senegal. The girls were 13.3 +/- 0.5 years at the start of the study (June 1997) and were followed annually for the next 2 years during puberty. Data collected during each round included: 1) pubertal status (as assessed by breast development and occurrence of menarche); 2) selected anthropometric dimensions (weight, stature, arm circumference, and six skinfolds); and 3) physical activity levels quantitatively assessed using CSA accelerometers. During rounds 1 and 3, activity was also qualitatively reported by direct minute-by-minute observations. A food consumption survey was performed once during the 3(rd) round, using an individual food weighing method. Girls of this sample had high levels of energy expenditure with daily physical activity levels (PALs) ranging from 1.70 to 1.85 multiples of basal metabolic rate. Energy intakes were, on average, sufficient to meet energy and protein requirements, although micronutrient deficiencies were likely to exist. Activity levels declined with age between the 1(st) and 3(rd) rounds. Stepwise regression analyses showed that stature was negatively correlated with both total daily and day-time activity, whereas the body mass index was positively associated with this measure. Pubertal status and subcutaneous fatness were not significant predictors of activity levels. The contribution of these adolescent girls to the everyday tasks of the household was considerable. They spent more than 3 hours 30 minutes per day in domestic duties.

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Objective: To study the relation between sleep habits, nutritional status, growth and maturation in a group of African adolescent girls. The main hypothesis to be tested was that sleep length could be an effective way to spare energy, and thus malnourished girls sleep longer than normal girls. Design: Three repeated yearly surveys (1997)(1998)(1999)) on a subsample of girls drawn from a larger study cohort on growth at adolescence. Setting: The Niakhar district in the central part of Senegal. Subject: In total, 40 girls were initially drawn. Missing girls were replaced at each round by girls having the same characteristics and belonging to the same cohort. Intervention: At each round, data on pubertal development (breast stages and occurrence of menarche), growth and nutritional status were collected. Adolescents wore an accelerometer for three or four consecutive nights and days at each round. Results: At the beginning of the survey, girls were 13.370.5 y old. They were under international reference values in weight and height. Their mean sleep duration was 8.570.9 h. Their puberty status did not influence their sleep habits; however, they slept more in March than in June, which was related to the seasonal change in daylight. There was a significant relation between body mass index and sleep habits: thinner girls slept a longer time and more quietly than the more corpulent girls. Conclusion: The nutritional status of these girls influenced their sleep habits: this may have been either a direct causal relation or a consequence of a protective attitude on the part of the mothers towards the frailer girls. Sponsorship: The R024 'Epidémiologie et Prévention' of the IRD (France) and the Nestlé Foundation.

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Background: In rural Africa, women and adolescent girls sustain a high burden of

Senegal is in a very favourable geographical position for sea fishing. Its coast has an upwelling favouring a good development of phytoplankton very appreciated by the various fish families that populate its Exclusive Economic Zone (EEZ). The little pelagic fish make up the majority of landings. The dynamics of this family of resources is very complex while its perfect mastery is essential for a fishing well controlled maritime. The mathematical models that exist in the literature have not address the different issues related to maritime fisheries and climate change in the Senegalese fishing areas. The linear programming model in integer numbers has been developed after calculation of equilibrium biomass, catches at equilibrium catchability by the application of Schaefer and Freon models in the  Senegalese Economic Exclusive Zone. Two proposals have been developed to better explain the tools used in the writing of the mathematical model. The simulation results were led to the design of a linear integer Program (PLNE). The objective is to maximize the biomass of this family of fish resources on the Petite C\^ote, Grande C\^ote and Cape Verde depending on samples and climate change. In the application of the model, real data made it possible to test the Linear program in integer numbers obtained. This optimization study allowed us to find an effective way to maximize recruitment within this resource family. This consists in setting up several less expensive marine refuges to build in the fishing zones targeted by the study. The simulation computer program of the model is presented in the appendix.

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Small coastal pelagic fish are one of the fish families most affected by sea fishing. This man-made phenomenon leads to an imbalance in the marine and coastal ecosystem and is one of the main causes of migration north and offshore of the ranges. We used the ordinary differential equations to model the interactions existing between small pelagic resources and fishermen. Modelling follows the same of the Lotka-Volterra equations with a difference in the number of variables. This study confirmed the instability of the marine ecosystem. The objective is first of all to model a system of three interacting individuals composed of two distinct types of predators and two types of prey, and then optimise this interaction with the aim of conserving biodiversity in the ecosystem under study. Determining the Jacobian matrix made it possible to calculate the reproduction rate basic (R 0). The study of the strong connectedness has made it possible to reduce the number of variables without losing the objective of the study. A computer program implemented on the language computer python facilitated the visualisation of the results.