44 research outputs found

    L'amélioration des plantes tropicales

    Get PDF

    Humanitarian Demining and Robotics

    Get PDF
    Mines were used for the first time during the American Civil War in the United States (1861-1865). Anti-tank mines were later ameliorated and laid on the battlefields of the First World War. Mine clearing operations did not pose major problems with those visible and easy-to-detect anti-tank mines. The reason why Anti-personnel mines have been conceived and systematically used on the anti-tank minefields during the Second World War was because such mines prevented the enemy from easy demining of the defense system

    Whole-cell analysis of low-density lipoprotein uptake by macrophages using STEM tomography

    Get PDF
    Nanoparticles of heavy materials such as gold can be used as markers in quantitative electron microscopic studies of protein distributions in cells with nanometer spatial resolution. Studying nanoparticles within the context of cells is also relevant for nanotoxicological research. Here, we report a method to quantify the locations and the number of nanoparticles, and of clusters of nanoparticles inside whole eukaryotic cells in three dimensions using scanning transmission electron microscopy (STEM) tomography. Whole-mount fixed cellular samples were prepared, avoiding sectioning or slicing. The level of membrane staining was kept much lower than is common practice in transmission electron microscopy (TEM), such that the nanoparticles could be detected throughout the entire cellular thickness. Tilt-series were recorded with a limited tilt-range of 80u thereby preventing excessive beam broadening occurring at higher tilt angles. The 3D locations of the nanoparticles were nevertheless determined with high precision using computation. The obtained information differed from that obtained with conventional TEM tomography data since the nanoparticles were highlighted while only faint contrast was obtained on the cellular material. Similar as in fluorescence microscopy, a particular set of labels can be studied. This method was applied to study the fate of sequentially up-taken low-density lipoprotein (LDL) conjugated to gold nanoparticles in macrophages. Analysis of a 3D reconstruction revealed that newly up-taken LDL-gold was delivered to lysosomes containing previously up-taken LDL-gold thereby forming onion-like clusters

    Analyse préliminaire de la situation et des perspectives de la culture du haricot de Lima (Phaseolus lunatus L.) sur la Côte péruvienne (Vallées d'Ica, Pisco et Casma)

    Get PDF
    Preliminary analysis of the situation and prospects of the Lima bean crop (Phaseolus lunatus L.) in the Peruvian Coast (Valleys of Ica, Pisco and Casma). The Lima bean, Phaseolus lunatus L., is a crop of regional importance on the Peruvian Coast. Within the framework of a collaborative project between the ""faculté universitaire des Sciences agronomiques'"" in Gembloux and the ""Universidad Nacional Agraria La Molina"" in Lima, we carried out a diagnosis of this speculation in the Ica, Pisco and Casma valleys in order to define the constraints which limit crop yields and to suggest improvements within the reach of the smallholders. To achieve these objectives we carried out a formal survey, centred on the Lima bean crop and smallholder relations with the agro-socio-economical environment, and an informal survey, centred on the studied farm systems. To complete these data we met some key informants belonging to all the sectors in contact with agriculture. This study allowed us to identify five undersystems in the farm systems of the Peruvian Coastal Valleys. These undersystems are: cotton, commercial food crops, self-subsistence food crops, livestock and fruit trees. The Lima bean usually belongs to the commercial food crops undersystem. There are two types of constraints. External constraints affect all the components of the farm system and are mainly: end of State support to agriculture, liberalization of trade and unavailability of credit. Internal constraints directly affect the Lima bean crop. Low income leads to a deficiency in pest control and adequate crop management. The Lima bean is also in competition with other components of the system such as cotton and common bean

    Des modèles biologiques à l'amélioration des plantes

    Get PDF

    Manual sobre técnicas estandarizadas para la investigacion del mejoramiento del cocotero

    Get PDF
    El Instituto Internacional de Recursos Fitogenéticos (IPGRI), tomando en cuanta las recomendaciones aportadas por 15 países productores de cocotero, estableció una Red Internacional de Recursos Genéticos del Cocotero (COGENT) para la coordinación de actividades de importancia nacional, regional y global, particularmente en la exploración, colección, conservación y utilización del cocotero, y para establecer bases las de colaboración sobre los amplios aspectos de la investigación y desarrollo del cultivo. Una de las primeras actividades de COGENT fue trabajar para homologar las técnicas de investigación. El Manual STANTECH, como se ha llamado a este documento, permitirá a productores de cocotero e investigadores del germoplasma de este cultivo, utilizar técnicas estandarizadas a nivel mundial, como guías para el cultivo y la conservación del germoplasma. Se espera que este manual ayude a los investigadores del cocotero a obtener mejores resultados y estos puedan ser comparados, lo cual permitirá acelerar el desarrollo de variedades mejoradas para millones de agricultores dedicados a este cultivo

    Relative frequencies of inherited retinal dystrophies and optic neuropathies in Southern France: assessment of 21-year data management

    Get PDF
    PURPOSE: Inherited retinal dystrophies (IRDs) and inherited optic neuropathies (IONs) are rare diseases defined by specific clinical and molecular features. The relative prevalence of these conditions was determined in Southern France. METHODS: Patients recruited from a specialized outpatient clinic over a 21-year period underwent extensive clinical investigations and 107 genes were screened by polymerase chain reaction/sequencing. RESULTS: There were 1957 IRD cases (1481 families) distributed in 70% of pigmentary retinopathy cases (56% non-syndromic, 14% syndromic), 20% maculopathies and 7% stationary conditions. Patients with retinitis pigmentosa were the most frequent (47%) followed by Usher syndrome (10.8%). Among non-syndromic pigmentary retinopathy patients, 84% had rod-cone dystrophy, 8% cone-rod dystrophy and 5% Leber congenital amaurosis. Macular dystrophies were encountered in 398 cases (30% had Stargardt disease and 11% had Best disease). There were 184 ION cases (127 families) distributed in 51% with dominant optic neuropathies, 33% with recessive/sporadic forms and 16% with Leber hereditary optic neuropathy. Positive molecular results were obtained in 417/609 families with IRDs (68.5%) and in 27/58 with IONs (46.5%). The sequencing of 5 genes (ABCA4, USH2A, MYO7A, RPGR and PRPH2) provided a positive molecular result in 48% of 417 families with IRDs. Except for autosomal retinitis pigmentosa, in which less than half the families had positive molecular results, about 75% of families with other forms of retinal conditions had a positive molecular diagnosis. CONCLUSIONS: Although gene discovery considerably improved molecular diagnosis in many subgroups of IRDs and IONs, retinitis pigmentosa, accounting for almost half of IRDs, remains only partly molecularly defined

    La Chaire Sud-Nord. Un exemple de partenariat entre les pays du Sud et du Nord

    No full text
    corecore