查看更多>>摘要：Une approche traditionnelle en nutrition a longtemps ete d'etudier l'effet d'un regime ou bien d'un nutriment donne sur une fonction particuliere ou un organe cible, ceci pour expliciter les mecanismes par lesquels les macro et micronutriments interviennent dans les voies metaboliques. Le developpement de techniques analytiques tres performantes et d'outils a haut debit comme par exemple la metabolomique ouvre maintenant un champ d'investigation beaucoup plus large permettant d'integrer un ensemble de reponses biologiques resultant de la complexite de l'aliment et des regimes alimentaires. La metabolomique consiste en l'acquisition a partir de fluides biologiques (sang, urine, salive) de profils metaboliques complexes par l'analyse de centaines de metabolites le plus souvent par 1H-RMN, ou differentes techniques de couplage (HPLC-MS ou GC-MS) et leur comparaison par analyses statistiques multivariees. Elle s'est d'abord developpee dans le champ de la toxicologie pour predire les effets toxiques de medicaments dans les phases precoces de developpement. Les etudes en nutrition sont encore recentes mais differents programmes de recherche concernent l'identification de marqueurs precoces de desequilibres metaboliques associes a l'apparition de pathologies. Deux approches sont possibles: la premiere est une approche ciblee qui concerne l'etude d'une voie metabolique definie comme par exemple le metabolisme des glucides ou celui des lipides. La deuxieme est une approche globale qui consiste a definir une empreinte metabolique en caracterisant le plus grand nombre possible de metabolites afin d'identifier les diverses voies metaboliques perturbees suite au stimuli. Toutefois, les bases de donnees << metabolites >> permettant la saisie et la consultation de molecules identifiees lors d'explorations nutritionnelles sont encore insuffisantes pour permettre l'identification d'un grand nombre de metabolites. Chez l'homme, il existe egalement une variabilite interindividuelle importante ce qui represente un autre facteur limitant pour cette approche a haut debit. De plus, contrairement aux effets des toxiques, les effets lies a un changement de regime sont souvent de faible amplitude ce qui peut entra?ner des difficultes de detection et d'identification des metabolites. La plateforme d'exploration du metabolisme de Clermont-Ferrand participe au developpement de l'outil metabolomique dans le domaine de la nutrition et de la bioinformatique en partenariat avec le centre de bioinformatique de Bordeaux (CBiB) en particulier dans le cadre de l'ANR Metaprofile. Il s'agit de structurer une base de donnees en nutrition incluant non seulement des donnees de metabolomique mais egalement des donnees complementaires de transcriptomique et de proteomique afin d'interroger et de croiser les differents jeux de donnees, et ainsi obtenir l'ensemble des informations des genes aux metabolites.
查看更多>>摘要：La recente augmentation des prix agricoles (suivie d'une decroissance qui semble devoir etre aussi profonde que le pic avait ete eleve) interesse evidemment quiconque se trouve concerne par l'economie agroalimentaire, que ce soit comme acteur ou comme observateur. La Societe francaise d'economie rurale, creee pour faciliter les contacts entre chercheurs en sciences sociales et praticiens, s'est donc tres naturellement trouvee conduite à organiser un colloque pour faire le point des reflexions sur la question, tenter de decrypter l'avenir, et surtout, envisager de nouveau travaux de recherche. Il est en effet necessaire de mieux comprendre les phenomenes de ce type, si l'on veut etre en mesure de les prevenir.
查看更多>>摘要：Tout d'abord, permettez-moi de vous souhaiter la bienvenue, en tant que Secretaire general des Chambres d'agriculture, dans ces locaux de I'Assemblee permanente que la plupart d'entre vous connaissent deja.
查看更多>>摘要：The article analyses the short term and structural causes of the explosion and collapse of agricultural prices. It exempts China and India and underlines the U.S. and EU responsibilities: agro-fuels, financial speculation, lower ending stocks of cereals, their food trade deficit and the EU deficit in cereal trade in 2007-08. The article reminds the structural mechanisms having undermined the agricultural economies of developing Countries, victims of food riots, following the progressive liberalization of agricultural trade.
查看更多>>摘要：How to explain the recent developments in the prices of agricultural raw materials? This article tries to trace the chronology of events and identify the mechanisms by which factors of change in agricultural prices act. From this analysis of temporal and causal effects an important lesson emerges, namely the difficulty if not the impossibility to isolate the responsibility of a particular determinant, even more to quantify it. Hence also the need to develop the economic analysis of agricultural prices, of their trends and determinants, including through the use of quantitative structural models, i.e., models that explicitly derived suplly and demand functions from behaviours of private and public actors.
Francoise GERARDMarie Gabrielle PIKETTYDCIRAD, UMR MOISA et Universite de Sao PaoloJean-Marc BOUSSARD
7页
查看更多>>摘要：This article analyzes the recent surge in market prices of raw materials, as the result of a feverish episode, characteristic of these markets when they are not regulated. Are these fluctuations exogenous or endogenous? Significant for understanding the system or not critical? Most models assume that they are negligible and requirements arising from this are those of a minimal state intervention in economic life and "faith in free markets" as policy development. However, we must acknowledge the limited progress achieved in recent decades, in the situation of low-income countries, particularly in Africa, The requirements from the dominant models in economics have been ineffective, leading to reflect on their ability to describe the process and to focus on opportunities for improvement. The model IDS CIRAD is an attempt in that direction.
查看更多>>摘要：This article presents an overview of the development of agri-food system in the world, the disparity in productivity and income the long terme downward trend in international agricultural prices, the world agricultural divide and its consequences in terms of poverty and malnutrition. Given this situation of poor farmers it analyses what should be the components of an effective policy development.
查看更多>>摘要：What can do the markets? This article examines through the light of current and recent past the contributions and limits of agricultural futures markets. Despite the crisis of agricultural raw materials, the markets seem to have very well played their role, If developed countries must stay under the discipline of markets, despite their tendency to "irrational exuberance'' one must recognize that markets do not ensure the development of poor countries. So, it is necessary to allow those countries to deploy autonomous agricultural policies, whichmeahs that they can protect themselves from fluctuations in external markets.
查看更多>>摘要：The crisis that we have known, reflects structural imbalances that should not be underestimated. This article intends to draw on one hand, the contours of an enabling economic environment for development of world agriculture (rules for least developed countries, reducing risk and exposure of the agricultural economic fluctuations and market volatility) and second, to review the challenges that agricultural development must now take into account, to be "sustainable" (new societal and environmental requirements).
查看更多>>摘要：Sunflower oil is rich in polyunsaturated fatty acids and in minor components (1 % of the oil fraction) including phytosterois, tocopherols, waxes and others components. This study evaluates the content and composition of the phytosterois in four sunflower hybrids during two growing seasons (2002 & 2003) and in seven more hybrids in a multifocal study in 2003. The phytosterol content in the maturing seeds was followed from flowering stage till full maturity. The kinetics of phytosterois accumulation was similar to that of fatty acids: a rapid increase until 25 Days After Flowering DAF and a stabilization after SO DAF. However, the temperature during the seed development induced changes in the phytosteroi content, since the total amount of phytosterois was significantly increased by high temperatures in some hybrids. On the other hand, the comparison of phytosteroi content in the 7 1 hybrids tested in 2003 shows significant differences in phytosteroi content between hybrids and low location X hybrid interaction. In this study the environment effect was the major source of variation. This study shows that phytosteroi content in sunflower oil can be promoted though combined action on selection and growth conditions.
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