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Recommandations et méthodologies pour la construction d'un corpus textuel annoté
Get PDFCe document, fondé sur les retours d'expérience de l'UMR TETIS et la littérature scientifique, propose une méthodologie générique pour la création d'un guide d'annotation et la production de jeux de données textuelles (corpus) annotés. Il couvre les aspects méthodologiques, de stockage, de partage et de valorisation des données, en intégrant des définitions et des exemples pour guider chaque étape, offrant ainsi un cadre complet pour accompagner la constitution et l'exploitation de corpus dans divers contextes de recherche
Éléments de plaidoyer pour la réduction de l'utilisation des pesticides de synthèse dans les agricultures du Sud
Get PDFComparative analysis of CFD modeling and process Simulation for pyro-gasification of biomass
Get PDFA comparative analysis of Computational Fluid Dynamics (CFD) modeling and process simulation (SIM) was carried out to evaluate biomass pyro-gasification, using experimental data from agave bagasse (AB) as a case study. Experimental data were obtained via thermogravimetric analysis (TGA) under varying conditions, including non-isothermal (700 to 1000 °C) and isothermal (900 °C and 950 °C) gasification at different air-to-biomass ratios (ABR). CFD modeling in COMSOL Multiphysics focused on micro-scale mass and heat transfer phenomena, while Aspen Plus simulations provided macro-scale process insights. Results showed that SIM closely matched experimental product yields under isothermal conditions (maximum deviation: 4.23 wt.%), while CFD excelled in predicting gas composition under non-isothermal conditions (e.g., H₂ deviation: 3.29 vol.%). Sensitivity analysis showed how temperature and ABR are critical factors that influence the product yield and gas composition, highlighting the strengths of each modeling approach. These findings underline the potential of integrating CFD and SIM approaches for improving the accuracy of biomass conversion modeling, paving the way for optimized process designs and scalable industrial applications
Grazing affects soil organic carbon stocks directly and indirectly through herbaceous species diversity in sahelian savanna ecosystems
Get PDFThe impact of livestock grazing on soil organic carbon (SOC) stocks in the Sahel has been poorly documented due to a lack of data from different grazing intensities. This study evaluated SOC stocks under four grazing intensities within 0–30 cm soil depth in dry savanna ecosystems of Senegal. It also examined possible indirect relationships between grazing and SOC through herbaceous species diversity, herbaceous biomass, and carbon–nitrogen ratio. Four sites representing high, moderate, light, and no grazing intensity levels were selected. Transect survey methods were used for sampling soil and vegetation data within each of the sites. Data were analyzed using mixed-effects models and piecewise structural equation modeling (pSEM). SOC stocks were significantly different among the four grazing intensities, and higher stocks were observed with increased intensity. Furthermore, high-intensity grazing was shown to reduce the carbon–nitrogen ratio by negatively affecting the diversity of herbaceous species, which indirectly promoted SOC stocks. In conclusion, this study found that increased grazing intensity promoted SOC stocks both directly and indirectly through herbaceous species diversity
Foot-and-mouth disease dynamics in multi-species livestock systems at the interface of African protected areas
Get PDFMany pathogens have the capacity to infect multiple hosts. Multi-species epidemiological systems are characterized by populations that interact and perform different functions in pathogen transmission and maintenance. This study investigated the epidemiological dynamics of foot-and-mouth disease (FMD) virus in cattle and goats and their respective functions in disease circulation within sympatric livestock populations adjacent to wildlife areas in Zimbabwe. Through year-long longitudinal serological monitoring, the spatial distributions of FMD antibodies and associated risk factors were examined. The results revealed significantly greater FMDV seroprevalence in cattle than in goats, with serostatus in cattle being influenced by proximity to wildlife areas. In contrast, goats presented a lower seroprevalence, less variation among age groups, and no association with proximity to protected areas. On the other hand, clustering analysis indicated the absence of clustering of seropositive individuals at the herd scale, suggesting low levels of virus transmission between animals belonging to the same herd in both species. These findings highlight the significance of context-dependent interactions among hosts, particularly with wildlife. This study emphasizes the necessity of comprehensive surveillance and strain identification across multiple sympatric species, both wild and domestic, for the effective management of multi-host pathogens. In conclusion, this research contributes to understanding the complex dynamics of FMD transmission in rural areas in Zimbabwe and emphasizes the importance of tailored surveillance strategies in diverse ecological settings
Crop gains induced by diversification exceed crop losses to diseases and weeds in a low-input rice cultivation system
Get PDFCrop losses to pests, or crop gains to diversification: what matters most ? This is a pivotal question for the acceptance of crop diversification solutions by farmers and breeders. At the intraspecific level in particular, the magnitude of beneficial effects of mixing varieties on crop yield compared to disease attacks and weed invasion in the absence of pesticide remains questioned. Here, we quantified for the first time the relative importance of different types of biotic interactions – crop-crop interactions, crop-fungi interactions and crop-weed interactions, on grain yields in a region of the world where alternative agricultural practices are urgently needed to face the multiple pressures induced by global changes. We evaluated the performance of ten upland rice varieties of Madagascar highlands using a field trial where all varieties were grown in pure stands and in bi-variety mixtures. Grain production and disease attacks by Pyricularia oryzea were assessed in all varieties and plots. Weed biomass was recorded in all plots. We also measured plant traits involved in plant-plant interactions - plant height and flowering time in particular - for all plots and varieties to identify generic assembly rules for optimizing the performance of varietal mixtures. We found strong positive effects of rice mixture on both crop yield and pathogen resistance while weed biomass remained constant and high whatever the experimental condition. When statistically controlling for one pressure, we demonstrated that the beneficial effects of crop-crop interactions on yield largely overcame the negative effects of crop-fungi and crop-weed interactions. The average height of varieties in mixtures as well as their height plasticity had strong predictive power of crop yields, confirming the great potential of trait-based approaches to design innovative cropping system. Overall, the predominant, positive effect of varietal mixtures over disease and weed pressures represents a key argument for crop diversification
Review on pounded yam extensibility texture of 138 genotypes analysed by Kieffer dough extensibility at CNRA, Côte d'Ivoire
Get PDFThe CNRA yam genetic resources collection contains a diversity of accessions consisting of traditional, introduced and hybrid varieties. This collection was subjected to characterization of the quality of pounded yam (foutou) by texture in order to identify varieties suitable for making pounded yam. The instrumental texture parameters measured are the extensogram peak force (N), extensibility (mm), and extension area (N.mm). The results show that the measured parameters are positively and strongly correlated. Among these parameters, the extension area (N.mm) best discriminates among the genotypes while the extensibility (mm) best discriminates between the two species (alata and rotundata). PCA coupled with ascending hierarchical classification (ACH) made it possible to screen the varieties into three classes taking into account their extensibility, that is to say their ability to make pounded yam that extends in texture. Class 1 consists of 10 varieties with high extensibility. The varieties in this class, all of them of D. rotundata species, are capable of making good pounded yam and can therefore be selected as priority genotypes. Class 2 includes 21 varieties with medium extensibility. The varieties in this class, which include both D. rotundata and D. alata varieties, can make pounded yam of medium quality. Class 3 includes few varieties of D. rotundata, and most of the D. alata varieties of have low extensibility and cannot produce good quality pounded yam (foutou)
Enhancing genomic selection in rubber tree (Hevea brasiliensis): Exploring the impact of genetic relatedness and QTL integration
Get PDFRubber tree breeding faces significant challenges, mainly due to the low female fertility of the plant, the long breeding cycles and the complex trait architecture. The advent of genomic selection offers a significant opportunity to explore more effective breeding strategies and accelerate genetic gains. This study investigates genomic prediction strategies for Hevea brasiliensis breeding, focusing on two biparental families connected by a common parent and evaluated among four different sites. The objective was to assess the impact of using full-sib and half-sib populations on prediction accuracy for key traits, rubber production and sucrose content. Results confirmed that prediction accuracies are higher when the training and validation populations consist of full-sibs (0.54 for rubber production and 0.36 for sucrose), as compared to half-sibs (0.17 for rubber production and 0.21 for sucrose). Combining full-sibs and half-sibs in the training population yielded prediction performance comparable to intra-family models (0.52 for rubber production and 0.37 for sucrose), providing a more practical option for breeding programs. Additionally, the integration of QTL information into prediction models for rubber production did not improved accuracy in full-sib (0.53) or half-sib (0.16) validation approaches and reduced accuracy in cross-validation, likely due to the polygenic nature of the trait and genotype-by-environment interactions. Rubber tree breeding programs could benefit from constructing training populations composed of multiple related families, simplifying logistics while maintaining prediction accuracy across more diverse populations than single biparental families. This approach offers a promising pathway to enhance the efficiency and genetic gains in rubber tree genomic selection
Coûts de production et rentabilité des cotonniers Bt (Cry1Ac) chez des petits producteurs au Brésil en 2007-2008
Get PDFAfrique : comment les drones de livraison pourraient transformer les prévisions météo
Get PDFAlors que les données météo manquent cruellement en Afrique, une idée fait son chemin. Celle d'utiliser les drones, de plus en plus nombreux dans les ciels du continent pour livrer par exemple des médicaments. Car ces derniers peuvent fournir également de nombreuses données météo