Structuration des filières biologiques en grandes cultures en Ile-de-France et conversion à l'AB d'opérateurs conventionnels

Les réflexions récentes sur les problématiques environnementales, principalement soulevées lors du Grenelle Environnement de 2007, ont fait émerger des décisions politiques en faveur de l’agriculture biologique. Ces orientations interrogent le développement de la production nationale et plus particulièrement la structuration des filières biologiques. En effet, de nombreux problèmes se posent au niveau de l’organisation de ces filières. De plus, l’émergence récente de nouveaux acteurs dans ce secteur, notamment des opérateurs du secteur conventionnel, pouvant contribuer à une profonde modification des filières biologiques est aujourd’hui perçue comme un moyen de développer à plus large échelle la production biologique nationale. La présente étude vise à approfondir la question des relations entre agriculteurs et opérateurs des filières en s’intéressant à la structuration des filières en grandes cultures biologiques en Île-de-France et à la « conversion » d’opérateurs conventionnels. A travers la caractérisation des modes de gestion des productions biologiques, une typologie d’opérateurs est proposée, se basant sur des leviers internes à leur structure, sur l’amont (contractualisation avec agriculteurs) et sur l’aval (marchés). Les résultats interrogent le développement futur de la production biologique sur le territoire francilien

Trafic routier et distances de sécurité : Le dilemme de l’agriculture en Ile-de-france

Les distances de sécurité représentent la solution la plus facilement applicable lorsqu’il s’agit de protéger les cultures agricoles de pollutions diffuses aux effets encore mal connus. Dans les années 90, certains acteurs de la filière céréales ont adopté des distances de sécurité entre les routes et les champs pour se prémunir de risques éventuels de contamination due à la pollution du trafic routier. Puis, ces mesures ont été partiellement délaissées en filière céréale alors qu’elles apparaissaient, moyennant des aménagements notoires, dans d’autres filières (herbes aromatiques). Notre étude porte sur la région Île-de-France, dont l’occupation agricole du territoire est importante et qui présente également une forte densité de réseaux routiers très fréquentés. Par une approche interdisciplinaire, notre objectif est donc de clarifier cette situation pour le moins complexe, de comprendre la genèse et l’évolution de ces distances tout en essayant d’en mesurer les effets en termes de gestion de risques (en lien avec divers usages du principe de précaution) tant sur le plan social que technique.The application of isolation distances is the easiest response for protecting agricultural crops from diffuse pollution effects still unknown. In the 90’s, some actors in the cereal supply chains have tried to limit potential risks by producing technical guidelines, including isolation distances between major roads and fields farmed under contract. These measures were then partially abandoned in the cereal sector but appeared later on in other sectors (aromatic herbs) with notable improvements. Our study focuses on the Ile-de-France region, which presents both a large agricultural area and an important road network. Through an interdisciplinary approach, our goal is to clarify this complex situation, to understand the genesis and evolution of these distances while measuring the effects concerning risk management (in connection with various uses of the precautionary principle) both socially and technically

The logistic leverages of short food supply chains performance in terms of sustainability

Local food supply chains seem now to be considered as a serious alternative to global ones in terms of sustainability. A lot of initiatives are developed and they often are associated with economical, social and environmental benefits. The main objective of this paper is to discuss the reality of these advantages. They are notably considered as a way to relocate or maintain agricultural activities, particularly in suburban areas. They are also supposed to be able to restore the connection between producers and consumers and to promote an alternative agricultural model based on "greener" production methods and the reduction of transport distances (the "food miles"). However, several studies have shown the limits of these models. Firstly, many important retailers have developed short food supply chains, questioning the local food system as an alternative business model. Moreover, it needs specific resources that many producers can't always offer. Secondly, an inadequacy between consumer's and producer's expectations can be observed, and many initiatives aren't based on collective approaches but on individual actions. Thirdly, these models aren't always based on alternative producing models (as organic agriculture) and the limitation of distances isn't always a factor of reduction of greenhouse gases. The paper tries to assess the performance of local food systems and the logistic leverages that could improve that performance. Long food chains have demonstrated the importance of logistic as a means to improve performance, and we can wonder how the improvement of the logistic organization of short food systems could increase their economical, social and environmental performance. Considering the fact that there's not only one local food system but a wide range of possibilities based on different numbers of intermediates or different geographic scales, our work will, at first, be based on Parker's article [2005] that defines short food supply chains as systems that reduce both the distance and the number of intermediates. After a brief presentation of short chains and of the advantages related to them, we will discuss their environmental assessment and impact, showing the role of transport and production mode in that dimension. An analysis of long food chains will then enable us to show how strategic logistics has become in that sector and the means necessary to the implementation of efficient logistic schemes. After a first look at logistics in short chains, we will propose a detailed study of the logistic schemes observed in fruit and vegetable basket systems in the Paris Region. This will lead us to build a typology of organizations to study their potential role in the improvement of short chains performance and more specifically their ability to improve coordination between the actors of those chains.LOGISTIQUE ; DEVELOPPEMENT DURABLE ; PERFORMANCE

Transitions des exploitations agricoles vers l’agriculture biologique dans un territoire

Des injonctions environnementales récentes ont été émises dans le domaine de la qualité de l’eau : la Directive-Cadre européenne sur l’Eau imposant l’atteinte d’un bon état écologique et chimique des masses d’eau en 2015 et le Grenelle Environnement qui a conduit à l’identification de 507 captages particulièrement menacés et désignés aujourd’hui comme « captages Grenelle ». Des changements de pratiques agricoles sont attendus pour limiter les pollutions diffuses d’origine agricole. L’agricult..

Collecte de grandes cultures biologiques en Île-de-France. Quels modes d’organisation et dynamiques d’intégration au sein de structures conventionnelles ?

Malgré des soutiens politiques importants, la production agricole biologique n’est pas en mesure, dans tous les secteurs, de satisfaire la demande des marchés. Dans le domaine des grandes cultures, l’émergence de nouveaux opérateurs de la collecte des productions, notamment des opérateurs du secteur conventionnel, apparaît aujourd’hui comme un moyen de développer à plus large échelle la production biologique nationale. À partir d’entretiens auprès d’organismes de collecte et de stockage intervenant dans la région Île-de-France, les auteures analysent les modalités de l’activité de collecte des grandes cultures biologiques et proposent une typologie d’opérateurs dans ce domaine. Les résultats interrogent le développement futur de la production biologique sur le territoire francilien, et plus largement, dans les régions de grandes cultures fortement liées aux opérateurs coopératifs et négociants.Despite significant political support, organic agricultural production is not able, in all sectors, to meet market demand. For the cash crops, the emergence of new collecting firms, including operators of the conventional sector, appears today as a way to develop larger scale organic production. From interviews with collecting firms involved in the Ile-de-France region, we analyze the activity of collecting cash crops and propose a typology of operators in this area. The results raises questions about the future development of organic production in the Parisian region, and more broadly, in the arable areas strongly related to cooperative operators and traders

A novel function for spumaretrovirus integrase: an early requirement for integrase-mediated cleavage of 2 LTR circles

Retroviral integration is central to viral persistence and pathogenesis, cancer as well as host genome evolution. However, it is unclear why integration appears essential for retrovirus production, especially given the abundance and transcriptional potential of non-integrated viral genomes. The involvement of retroviral endonuclease, also called integrase (IN), in replication steps apart from integration has been proposed, but is usually considered to be accessory. We observe here that integration of a retrovirus from the spumavirus family depends mainly on the quantity of viral DNA produced. Moreover, we found that IN directly participates to linear DNA production from 2-LTR circles by specifically cleaving the conserved palindromic sequence found at LTR-LTR junctions. These results challenge the prevailing view that integrase essential function is to catalyze retroviral DNA integration. Integrase activity upstream of this step, by controlling linear DNA production, is sufficient to explain the absolute requirement for this enzyme. The novel role of IN over 2-LTR circle junctions accounts for the pleiotropic effects observed in cells infected with IN mutants. It may explain why 1) 2-LTR circles accumulate in vivo in mutants carrying a defective IN while their linear and integrated DNA pools decrease; 2) why both LTRs are processed in a concerted manner. It also resolves the original puzzle concerning the integration of spumaretroviruses. More generally, it suggests to reassess 2-LTR circles as functional intermediates in the retrovirus cycle and to reconsider the idea that formation of the integrated provirus is an essential step of retrovirus production

Designing a paediatric study for an antimalarial drug including prior information from adults

International audienceThe objectives of this study were to design a pharmacokinetic (PK) study by using information about adults and evaluate the robustness of the recommended design through a case study of mefloquine. PK data about adults and children were available from two different randomized studies of the treatment of malaria with the same artesunate-mefloquine combination regimen. A recommended design for pediatric studies of mefloquine was optimized on the basis of an extrapolated model built from adult data through the following approach. (i) An adult PK model was built, and parameters were estimated by using the stochastic approximation expectation-maximization algorithm. (ii) Pediatric PK parameters were then obtained by adding allometry and maturation to the adult model. (iii) A D-optimal design for children was obtained with PFIM by assuming the extrapolated design. Finally, the robustness of the recommended design was evaluated in terms of the relative bias and relative standard errors (RSE) of the parameters in a simulation study with four different models and was compared to the empirical design used for the pediatric study. Combining PK modeling, extrapolation, and design optimization led to a design for children with five sampling times. PK parameters were well estimated by this design with few RSE. Although the extrapolated model did not predict the observed mefloquine concentrations in children very accurately, it allowed precise and unbiased estimates across various model assumptions, contrary to the empirical design. Using information from adult studies combined with allometry and maturation can help provide robust designs for pediatric studies

Combining eco-social and environmental indicators to assess the sustainability performance of a food value chain: A case study

Stakeholders are increasingly demanding transparency on food value chain sustainability performance. Today there is no standard framework to meet this demand and support defining indicators to be used to conduct an overall sustainable performance assessment. This paper mobilizes existing frameworks and indicators to build new sustainable performance metrics for actors willing to work together for their value chain sustainability. Popular methods or tools for assessing dimensions of agrifood products or activities are selected and analyzed to determine how they could contribute to this metric. The analysis aims to distinguish the sustainable development pillars addressed (economic, environmental and/or social), the frames concerned (life cycle thinking or not - multi-actor or not), and the focus of performance measured (drivers, pressures, states, impacts, responses). This categorization is then used to develop a proposal for specifications adapted to food value chain sustainability performance assessment. The applicability of the framework is demonstrated through a case study in a pork agrifood value chain

Effect of nitrogen-rich cell culture surfaces on type X collagen expression by bovine growth plate chondrocytes

Background: Recent evidence indicates that osteoarthritis (OA) may be a systemic disease since mesenchymal stem cells (MSCs) from OA patients express type X collagen, a marker of late stage chondrocyte hypertrophy (associated with endochondral ossification). We recently showed that the expression of type X collagen was suppressed when MSCs from OA patients were cultured on nitrogen (N)-rich plasma polymer layers, which we call "PPE:N" (N-doped plasma-polymerized ethylene, containing up to 36 atomic percentage (at.%) of N.Methods: In the present study, we examined the expression of type X collagen in fetal bovine growth plate chondrocytes (containing hypertrophic chondrocytes) cultured on PPE:N. We also studied the effect of PPE: N on the expression of matrix molecules such as type II collagen and aggrecan, as well as on proteases (matrix metalloproteinase-13 (MMP-13) and molecules implicated in cell division (cyclin B2). Two other culture surfaces, "hydrophilic" polystyrene (PS, regular culture dishes) and nitrogen-containing cation polystyrene (Primaria (R)), were also investigated for comparison.Results: Results showed that type X collagen mRNA levels were suppressed when cultured for 4 days on PPE: N, suggesting that type X collagen is regulated similarly in hypertrophic chondrocytes and in human MSCs from OA patients. However, the levels of type X collagen mRNA almost returned to control value after 20 days in culture on these surfaces. Culture on the various surfaces had no significant effects on type II collagen, aggrecan, MMP-13, and cyclin B2 mRNA levels.Conclusion: Hypertrophy is diminished by culturing growth plate chondrocytes on nitrogen-rich surfaces, a mechanism that is beneficial for MSC chondrogenesis. Furthermore, one major advantage of such "intelligent surfaces" over recombinant growth factors for tissue engineering and cartilage repair is potentially large cost-saving