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The Sahara conceals large quantities of water stored at depth and inherited from ancient times. A recent study by the IRD and its partners has just shown that this groundwater is not entirely fossil, but resupplied every year. Using a method based on data obtained by satellite, scientists estimated the variations in the volume of water lying under the northern Sahara desert: the current rate of recharge is on average 1.4 km3 per year, for the period 2003-2010. This represents 40% of withdrawals, mainly for irrigation to support the oasis economy. The inputs therefore do not compensate for the withdrawals, but their existence means that these transboundary aquifers, the main water resource of semi-arid regions in Algeria and Tunisia, could be managed sustainably.
The Saharan cousin of Mediterranean olive trees remains largely unknown. However, this subspecies (called the Laperinne's olive tree) is of great interest for several reasons. IRD researchers and their partners showed that its longevity is ensured by its original vegetative reproduction. Extremely drought-resistant, this "relict" tree could act as a genetic resource to improve its domestic counterparts, provided conservation actions are implemented to prevent its disappearance.
Men and women in Tunisia are not equal before the scales. Tunisian women are three times as likely to suffer from obesity as their male compatriots. This great inequality was revealed in a study by IRD and its partners ( 1), and differs from what nutritionists have observed in the North, where more men tend to be overweight. The disparity is even greater in cities: a sedentary lifestyle, temptations offered by mass-market retail… Their role in society makes women particularly vulnerable to risk factors in an urban environment. Body mass index (BMI) is also increasing among those with a lower education level and without employment, further broadening the difference from their masculine counterparts.
A BMI above 25 increases health risks: cardiovascular diseases, diabetes, cancer, high blood pressure… The latter already affects nearly a third of all Tunisians above the age of 35, of which almost a million are obese today. Prevention is better than cure: healthcare authorities must aim their actions at the population segment that is most at risk, namely women.
Since the early 2000s the Sahara has come back strongly into the international political and media arena. The whole region is going through a period of turbulence stemming from its growing economic and strategic importance and a highly confused geopolitical environment. This situation stems from the “Arab spring” events, the fall of Colonel Gaddafi and the installation of Al Qaeda Organization in the Islamic Maghreb (AQIM) in Mali.
A special issue of the journal Hérodote has published review articles on these upheavals by IRD geographers and economists and their and their research partners. Beyond the geopolitical and security aspects, they describe the economic changes, the development of the trans-Saharan migrations and the race for raw materials pursued by the world’s great powers. All these powers seek the underground wealth the region conceals (such as oil, uranium, iron). Simultaneously coveted and feared, the Sahara never ceases to arouse concern in the international community.
Sleeping sickness is a parasitic infection which affects humans and animals alike in Africa. True to its name, it disturbs the sleep cycle: the patient sleeps during the day and stays awake at night. Sensory disturbance, motor coordination anomalies and mental confusion develop. The whole ...