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Rangelang Assesment of Kolo Ranch Savanna - Zaire. In a ranch where the number of heads are stabilised for over 25 years, the authors have analysed the productivity, stocking rate and the pasture management on the 51.000 ha natural rangelands. The referred region has a soudanian climate with a 5 months dry season. The grazing areas have been classified and mapped into 8 morpho-pedological units. Regarding the flora, these areas are : a) sandy soils covered by Loudetia arundinacea savannas (4, 1 % of total area), b) sandy clay/clayed soils covered mainly by Hyparrhenia diplandra savannas (44 %) on the plateaus and in the bottom areas, and by Hyparrhenia lecomtei savannas (26 %) on the poorer soils on the slopes and on the tops. The daily productions of these savannas available to animals have been evaluated in each various morpho-pedological units. These productions were respectively 1.9 and 3.8 times lower in average and at the end of the dry season than in the wet season. The pasture management (rotation on 5 plots) and the stocking rate used (2.5 LSU) are established in accordance with the constraints issued from the measurements of the productivity and the nuthtional value of the grass regrowth taken after the controlled burning of the plots. For this type of extensive rearing, the estimated average stocking rate seems to be carried out starting by the average of grass regrowth after burning during the dry season. Nevertheless, this type of forecasts would only be applicable to areas wider than the one utilised by a single herd which is the most practical working unit of rangelands for pasture management.

Edmond Kahn,1 Nicolas Tissot,3 Perrine Frere,3 Aurélien Dauphin,3 Mohamed Boumhras,2,4 Claude-Marie Bachelet,3 Frédérique Frouin,1 Gérard Lizard21Institut National de la Santé et de la Recherche Médicale (INSERM) U678/UMR-S UPMC, CHU Pitié-Salpêtrière, Paris, France; 2Equipe Biochimie du Peroxysome, Inflammation et Métabolisme Lipidique EA7270, Faculté des Sciences Gabriel, Université de Bourgogne-INSERM Dijon, France; 3Plateforme d'Imagerie cellulaire, UPMC, Paris, France; 4Laboratory of Biochemistry and Neuroscience, Applied Toxicology Group, Faculty of Science and Technology, Settat, MoroccoAbstract: In the present study, we make use of the ability of two-photon confocal laser scanning microscopes (CLSMs) equipped with tunable lasers to produce spectral excitation image sequences. Furthermore, unmixing, which is usually performed on emission image sequences, is performed on these excitation image sequences. We use factor analysis of medical image sequences (FAMIS), which produces factor images, to unmix spectral image sequences of stained structures in tissue sections to provide images of characterized stained cellular structures. This new approach is applied to histological tissue sections of mouse aorta containing labeled iron nanoparticles stained with Texas Red and counterstained with SYTO13, to obtain visual information about the accumulation of these nanoparticles in the arterial wall. The possible presence of Texas Red is determined using a two-photon CLSM associated with FAMIS via the excitation spectra. Texas Red and SYTO13 are thus differentiated, and corresponding factor images specify their possible presence and cellular localization. In conclusion, the designed protocol shows that sequences of images obtained by excitation in a two-photon CLSM enables characterization of Texas Red-stained nanoparticles and other markers. This methodology offers an alternative and complementary solution to the conventional use of emission spectra unmixing to localize fluorescent nanoparticles in tissue samples.Keywords: FAMIS, spectral excitation sequences, Texas Red, tunable excitation, unmixing