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388 - Revised Earth history favours the search for African gold
November 2011
Potential treasures lie concealed under the West African savannah in some of the Earth’s poorest countries. Extensive gold fields occur, over hundreds of kilometres, from Senegal to Niger. The rapid rise in precious metal prices over the past five years has prompted hugely intensified mineral exploration. Yet new veins must be found if this African gold rush is to continue.
A new discovery, published in Nature Geoscience , is now shaking up our understanding of the Earth and the prospects for exploration. The research team ( 4), led by an IRD geologist, used innovatory modelling software to take a fresh look at the origins of plate tectonics in the light of the geothermal history of the gold deposits in the West African gold fields. These investigations will lead to better ways of locating the emplacement of veins and their depth. This result is a fundamental one for the science which furthermore offers promising applications for West African countries.
384 - Sub-urban agriculture or how to practise effective recycling
September 2011
Since 2008, one out of two human beings is an urban dweller. With the galloping urbanization comes ever more abundant waste. What can be done with all this refuse? Waste management is a major challenge for the coming decades, particularly in Africa.
Sub-urban agriculture offers openings for effective recycling, but does present certain risks. IRD researchers and their partners( 1) surveyed the different farming actors and practices in the Burkina Faso capital, Ouagadougou, seeking a better understanding of the sector and ways of optimizing urban waste management. They found that nearly three quarters of farmers and nurserymen use this type of organic substrate (household waste, poultry feathers, fish scales, septic tank sludge etc.) to fertilize their soils. However, less than one third of them practise composting. Yet, application of raw urban waste on the soils can create serious health risks. As a solution, local councils will have to concentrate on compost awareness campaigns and work to improve accessibility to such materials.
Sub-urban agriculture is proving to be a great advantage for African cities, combining waste conversion, soil improvement and food security.
374 - Snakebites a public health problem in Africa
May 2011
One and a half million people per year are poisoned by snake venom in Sub-Saharan Africa. An IRD researcher recently analysed around 100 surveys and medical reports published over the past 40 years. No large-scale study of the situation had hitherto been conducted and public health authorities had underestimated the size of the problem. This means that currently only 10% of victims are treated, owing to a shortage of antivenoms * and lack of awareness among health care practitioners. Yet the clinical complications can be very serious, even fatal. A bite from a cobra or mamba can bring on death by asphyxia –due to respiratory paralysis– within 6h after the incident. Venom injected by the ocellated carpet viper, common in the African savannah, can cause haemorrhages leading to the victim’s death in a few days.
This new study provides authorities with more detailed and reliable figures which should enable them to readjust their health-care services in better tune with needs.
373 - Increasing rice production using genes from the African species
May 2011
Rice is the world’s most commonly used cereal food, feeding half of humanity. However, rice production will have to double within 20 years from now to meet the needs of a growing population.
Two species are used for cultivation, one Asian and the other African. The Asian species gives much stronger agronomic performances, but the African one is more rustic, more resistant to pathogens, more tolerant to drought and soil salinity.
With the aim of transferring these properties to Asian rice, IRD scientists and their research partners( 1) are seeking to overcome the sterility between the two species( 2). They used genome sequencing to compare the structure of a portion of chromosome, identified as the factor behind the reproductive barrier. These investigations, the first results of which were published recently in the journal PLoS One , have led to the definition of genetic markers allowing more rapid development of fertile lineages of improved Asian rice.
369 - Africa at a population turning point
March 2011
In the coming decades, the West African countries could benefit from a demographic window of opportunity to reduce their poverty. The arrival of 160 million young people on the labour market between 2010 and 2030 could accelerate economic growth. These countries could take advantage of this “demographic dividend”, which the emerging countries have been doing for 40 years. On condition that they lower their fertility rates, are still the highest in the world, with an average of five children per woman. That would enable them to reduce the number of economically non-active people being supported for each active individual..
An IRD researcher asserts this in a review published recently by the Agence française de développement (AFD), concerning a far-reaching survey( 1) conducted in 12 West African countries( 2): family planning and promotion of contraception are some of the main keys to sustainable economic growth. Yet to arrive at such a situation, these countries must assign 3 to 5 times the means currently given over to such a policy. Will they be able to manage this population turning point successfully?
