Gourlet-Fleury S.,CIRAD - Agricultural Research for Development
Philosophical transactions of the Royal Society of London. Series B, Biological sciences | Year: 2013
Large areas of African moist forests are being logged in the context of supposedly sustainable management plans. It remains however controversial whether harvesting a few trees per hectare can be maintained in the long term while preserving other forest services as well. We used a unique 24 year silvicultural experiment, encompassing 10 4 ha plots established in the Central African Republic, to assess the effect of disturbance linked to logging (two to nine trees ha-1 greater than or equal to 80 cm DBH) and thinning (11-41 trees ha-1 greater than or equal to 50 cm DBH) on the structure and dynamics of the forest. Before silvicultural treatments, above-ground biomass (AGB) and timber stock (i.e. the volume of commercial trees greater than or equal to 80 cm DBH) in the plots amounted 374.5 ± 58.2 Mg ha-1 and 79.7 ± 45.9 m3 ha-1, respectively. We found that (i) natural control forest was increasing in AGB (2.58 ± 1.73 Mg dry mass ha-1 yr-1) and decreasing in timber stock (-0.33 ± 1.57 m3 ha-1 yr-1); (ii) the AGB recovered very quickly after logging and thinning, at a rate proportional to the disturbance intensity (mean recovery after 24 years: 144%). Compared with controls, the gain almost doubled in the logged plots (4.82 ± 1.22 Mg ha-1 yr-1) and tripled in the logged + thinned plots (8.03 ± 1.41 Mg ha-1 yr-1); (iii) the timber stock recovered slowly (mean recovery after 24 years: 41%), at a rate of 0.75 ± 0.51 m3 ha-1 yr-1 in the logged plots, and 0.81 ± 0.74 m3 ha-1 yr-1 in the logged + thinned plots. Although thinning significantly increased the gain in biomass, it had no effect on the gain in timber stock. However, thinning did foster the growth and survival of small- and medium-sized timber trees and should have a positive effect over the next felling cycle. Source
Chevalier V.,CIRAD - Agricultural Research for Development
Clinical Microbiology and Infection | Year: 2013
Rift Valley fever (RVF), a vector-borne zoonotic disease caused by a phlebovirus (family Bunyaviridae), is considered to be one of the most important viral zoonoses in Africa. It is also a potential bioterrorism agent. Transmitted by mosquitoes or by direct contact with viraemic products, RVF affects both livestock and humans, causing abortion storms in pregnant ruminants and sudden death in newborns. The disease provokes flu syndrome in most human cases, but also severe encephalitic or haemorrhagic forms and death. There is neither a treatment nor a vaccine for humans. The disease, historically confined to the African continent, recently spread to the Arabian Peninsula and Indian Ocean. Animal movements, legal or illegal, strongly contribute to viral spread, threatening the Mediterranean basin and Europe, where competent vectors are present. Given the unpredictability of virus introduction and uncertainties about RVF epidemiology, there is an urgent need to fill the scientific gaps by developing large regional research programmes, to build predictive models, and to implement early warning systems and surveillance designs adapted to northern African and European countries. © 2013 European Society of Clinical Microbiology and Infectious Diseases. Source
CIRAD - Agricultural Research for Development and French National Institute for Agricultural Research | Date: 2013-01-15
The present invention relates to a solid fuel in the form of a powder, including at least one lignocellulosic component in the form of a powder. The present invention also relates to the method for preparing said lignocellulosic component in the form of a powder, as well as to the use thereof in the production of a solid fuel intended for an internal combustion engine or a burner. The invention further relates to a method for generating energy using the solid fuel according to the invention.
Institute Of Lenvironnement Et Of Recherches Agricoles and CIRAD - Agricultural Research for Development | Date: 2011-05-26
The invention provides a composition for the inoculation in a plant of agrobacteria transfected by expression vectors, in order to produce in said plant a protein of interest or a derivative of said protein, by deletion or by mutation, characterised in that it comprises
CIRAD - Agricultural Research for Development and Valorhiz | Date: 2012-03-07
Apparatus for physically analyzing soil includes a sample changer for receiving at least two soil-sample holders, and having an element for placing each sample holder and sample thereof in a measurement area, in turns, according to a cycle repeated over time, the apparatus including: elements for measuring the size of the samples; elements for measuring the potential of the samples containing water; and elements for measuring the weight of the samples, wherein all of the measuring elements are grouped together in the measurement area so as to be simultaneously used implemented for a given sample when the latter is placed in the measurement area. The shrinkage curve and water potential curve, obtained from the measurements, represent the change, over time, in the status of the water and structure of the soil sample during the drying thereof, and can be used to determine the hydrostructural characteristics of the soil.