Les stratégies de contrôle de la qualité sanitaire dans les Organisations de Producteurs de tomates

Our paper deals with free-riding issues in product safety control at the collective marketing level. It focuses on the empirical findings of the exhaustive face to face survey that has been conducted in 2007 by the authors with the quality managers of the tomato growers'unions of France. Our survey was supported by the National Tomato Charter, a regrouping of most of the French tomato growers'unions. Its aim was to identify the differences in monitoring and enforcement practices at the collective marketing level and to search for any group size effect on such practices. A main finding of our paper is that, beyond public regulation and collective rules imposed by the National Tomato Charter, POs implement voluntary control rules for a better control of free riding behavior within the group. Such additional rules differ both in monitoring intensity (measured by the number of pesticide residue analysis performed voluntarily by the group) and in sanction level (applied in case of deviation to the collective rule). Differences in safety control are not only triggered by customers specific requirements but also by group size (measured by the number of growers within the group). Eventually, our paper draws some perspectives for a more in-depth analysis of free riding issues. First, it calls for paying more attention to factors such as intra-group heterogeneity and differences in customers requirements. Second, it underlines the need for a more extensive analysis which includes safety control practices at the production level and wonders whether such practices are a complement or a substitute of control practices at the marketing level. ...French Abstract : Ce texte aborde les problèmes d'action collective dans le contrôle de la qualité sanitaire des produits avant leur mise en marché par les Organisations de Producteurs. Il est une synthèse des résultats de l'enquête menée auprès des responsables qualité de l'ensemble des OP adhérant à la Charte Nationale Tomate sur leurs pratiques de contrôle de la qualité sanitaire des tomates. L'enquête a eu le soutien des responsables de la Charte Nationale Tomate, qui regroupe la quasi-totalité de la production organisée en France. Elle avait pour objectif d'identifier la diversité des pratiques de contrôle au sein des OP et de mesurer l'effet de la "taille de l'OP" sur les modalités de contrôle mises en place. L'enquête montre qu'au-delà des règles communes imposées par la réglementation et la Charte Nationale Tomate, les OP mettent en place des démarches de contrôle diversifiées qui se différencient à la fois par l'importance de la surveillance (mesurée en nombre d'analyses de résidus de pesticides) et par le niveau des sanctions appliquées en cas de dérogation à la règle adoptée. Elle explique enfin la diversité de ces démarches, non seulement par les exigences de la clientèle mais aussi par la taille du groupe (mesurée par le nombre de producteurs). Notre rapport se termine par une discussion sur les améliorations à apporter à ce premier travail. Des précisions sont à apporter tout d'abord sur l'hétérogénéité intra et inter groupes et sur les niveaux d'exigences de la clientèle. Un complément d'analyse est ensuite nécessaire pour mieux caractériser l'effort de contrôle en amont du produit, au niveau de la production et pour étudier la complémentarité ou la substituabilité des deux types de contrôle: contrôle sur les pratiques en production, contrôle sur le produit.PRODUCERS' UNIOS; FREE-RIDING; MONITORING; ENFORCEMENT; CONTROL; PESTICIDE RESIDUES; TOMATO; FRANCE; ORGANISATIONS DE PRODUCTEURS; PASSAGER CLANDESTIN; SANCTION; CONTROLE; RESIDUS DE PESTICIDES; TOMATE

The PreVOCA experiment: modeling the lower troposphere in the Southeast Pacific

The Preliminary VOCALS Model Assessment (PreVOCA) aims to assess contemporary atmospheric modeling of the subtropical South East Pacific, with a particular focus on the clouds and the marine boundary layer (MBL). Models results from fourteen modeling centers were collected including operational forecast models, regional models, and global climate models for the month of October 2006. Forecast models and global climate models produced daily forecasts, while most regional models were run continuously during the study period, initialized and forced at the boundaries with global model analyses. Results are compared in the region from 40° S to the equator and from 110° W to 70° W, corresponding to the Pacific coast of South America. Mean-monthly model surface winds agree well with QuikSCAT observed winds and models agree fairly well on mean weak large-scale subsidence in the region next to the coast. However they have greatly differing geographic patterns of mean cloud fraction with only a few models agreeing well with MODIS observations. Most models also underestimate the MBL depth by several hundred meters in the eastern part of the study region. The diurnal cycle of liquid water path is underestimated by most models at the 85° W 20° S stratus buoy site compared with satellite, consistent with previous modeling studies. The low cloud fraction is also underestimated during all parts of the diurnal cycle compared to surface-based climatologies. Most models qualitatively capture the MBL deepening around 15 October 2006 at the stratus buoy, associated with colder air at 700 hPa

Carbon stable isotope analysis of cereal remains as a way to reconstruct water availability: preliminary results

Reconstructing past water availability, both as rainfall and irrigation, is important to answer questions about the way society reacts to climate and its changes and the role of irrigation in the development of social complexity. Carbon stable isotope analysis of archaeobotanical remains is a potentially valuable method for reconstructing water availability. To further define the relationship between water availability and plant carbon isotope composition and to set up baseline values for the Southern Levant, grains of experimentally grown barley and sorghum were studied. The cereal crops were grown at three stations under five different irrigation regimes in Jordan. Results indicate that a positive but weak relationship exists between irrigation regime and total water input of barley grains, but no relationship was found for sorghum. The relationship for barley is site-specific and inter-annual variation was present at Deir ‘Alla, but not at Ramtha and Khirbet as-Samra

The partitioning of poleward energy transport response between the atmosphere and Ekman flux to prescribed surface forcing in a simplified GCM

Recent studies have indicated that ocean circulation damps the atmospheric energy transport response to hemispherically differential energy perturbations, thereby muting the shifts of the Inter-Tropical Convergence Zone (ITCZ). Here, we focus on the potential role of Ekman heat transport in modulating this atmospheric response. An idealized representation of Ekman-driven heat transport (FE) is included in an aquaplanet slab ocean coupled to a gray radiation atmospheric model. We first alter the strength of FE in the control climate by tuning the gross stability of the Ekman layer SE. For a wide range of FE, the total poleward transport of energy remains nearly unchanged, but the ocean transports an increasing share for larger SE. The control climate is then perturbed by adding surface cooling in the Southern Hemisphere and warming in the Northern Hemisphere. The Ekman coupling damps the atmospheric energy transport response, as in previous coupled model experiments with full ocean dynamics. The ratio of the changes in Ekman to atmospheric energy transport is determined by the ratio of the gross stability in the Ekman layer to the atmosphere in the control climate, and is insensitive to the amplitude and location of forcing. We find that an unrealistically large SE is needed to reproduce the ratio of the changes in cross-equatorial oceanic to atmospheric energy transport in fully coupled models. The limited damping effect of Ekman transport highlights the need to examine the roles of deep circulation and subtropical gyres, as well as ocean heat uptake processes

Extratropical forcing and tropical rainfall distribution: energetics framework and ocean Ekman advection

Intense tropical rainfall occurs in a narrow belt near the equator, called the inter-tropical convergence zone (ITCZ). In the past decade, the atmospheric energy budget has been used to explain changes in the zonal-mean ITCZ position. The energetics framework provides a mechanism for extratropics-to-tropics teleconnections, which have been postulated from paleoclimate records. In atmosphere models coupled with a motionless slab ocean, the ITCZ shifts toward the warmed hemisphere in order for the Hadley circulation to transport energy toward the colder hemisphere. However, recent studies using fully coupled models show that tropical rainfall can be rather insensitive to extratropical forcing when ocean dynamics is included. Here, we explore the effect of meridional Ekman heat advection while neglecting the upwelling effect on the ITCZ response to prescribed extratropical thermal forcing. The tropical component of Ekman advection is a negative feedback that partially compensates the prescribed forcing, whereas the extratropical component is a positive feedback that amplifies the prescribed forcing. Overall, the tropical negative feedback dominates over the extratropical positive feedback. Thus, including Ekman advection reduces the need for atmospheric energy transport, dampening the ITCZ response. We propose to build a hierarchy of ocean models to systematically explore the full dynamical response of the coupled climate system

Stable isotopic composition of fossil mammal teeth and environmental change in southwestern South Africa during the Pliocene and Pleistocene

The past 5 million years mark a global change from the warmer, more stable climate of the Pliocene to the initiation of glacial-interglacial cycles during the Pleistocene. Marine core sediment records located off the coast of southwestern Africa indicate aridification and intensified upwelling in the Benguela Current over the Pliocene and Pleistocene. However, few terrestrial records document environmental change in southwestern Africa over this time interval. Here we synthesize new and published carbon and oxygen isotope data of the teeth from large mammals (>6 kg) at Langebaanweg (~5 million years ago, Ma), Elandsfontein (1.0 – 0.6 Ma), and Hoedjiespunt (0.35 – 0.20 Ma), to evaluate environmental change in southwestern Africa between the Pliocene and Pleistocene. The majority of browsing and grazing herbivores from these sites yield enamel 13 C values within the range expected for animals with a pure C3 diet, however some taxa have enamel 13C values that suggest the presence of small amounts C4 grasses at times during the Pleistocene. Considering that significant amounts of C4 grasses require a warm growing season, these results indicate that the winter rainfall zone, characteristic of the region today, could have been in place for the past 5 million years. The average 18O value of the herbivore teeth increases ~4.4‰ between Langebaanweg and Elandsfontein for all taxa except suids. This increase may solely be a function of a change in hydrology between the fluvial system at Langebaanweg and the spring-fed environments at Elandsfontein, or a combination of factors that include depositional context, regional circulation and global climate. However, an increase in regional aridity or global cooling between the early Pliocene and mid-Pleistocene cannot explain the entire increase in enamel 18O values. Spring-fed environments like those at Elandsfontein may have 75 provided critical resources for mammalian fauna in the mid-Pleistocene within an increasingly arid southwestern Africa ecosystem

New technologies and firm organization : the case of electronic traceability systems in French agribusiness

This paper considers the relationship between the adoption of electronic traceability systems (ETSs) and the organization of firms. More precisely, it analyzes the respective roles of a firm's organizational structure, and organizational changes, in the process of ETS adoption in agribusiness. We use data from the French "Organizational Changes and Computerization" survey from 2006. We test a probit model to demonstrate the organizational structure and organizational changes underlying the firm's ETS adoption choice. Results show that ETS adoption is strongly favored by organizations with heavy hierarchical structures, standardized managerial practices and contractual mechanisms with external partners. This adoption process seems to coevolve with the organization: firms that implemented an ETS during the observed period (2003-2006) have experienced the most important organizational changes in terms of managerial practices, information systems and contractual relations, as well as the strengthening of the intermediate levels in the hierarchy

Metabo-lipidomics of Fibroblasts and Mitochondrial-Endoplasmic Reticulum Extracts from ALS Patients Shows Alterations in Purine, Pyrimidine, Energetic, and Phospholipid Metabolisms

Amyotrophic lateral sclerosis (ALS) is characterized by a wide metabolic remodeling, as shown by recent metabolomics and lipidomics studies performed in samples from patient cohorts and experimental animal models. Here, we explored the metabolome and lipidome of fibroblasts from sporadic ALS patients (n = 13) comparatively to age- and sex-matched controls (n = 11), and the subcellular fraction containing the mitochondria and endoplasmic reticulum (mito-ER), given that mitochondrial dysfunctions and ER stress are important features of ALS patho-mechanisms. We also assessed the mitochondrial oxidative respiration and the mitochondrial genomic (mtDNA) sequence, although without yielding significant differences. Compared to controls, ALS fibroblasts did not exhibit a mitochondrial respiration defect nor an increased proportion of mitochondrial DNA mutations. In addition, non-targeted metabolomics and lipidomics analyses identified 124 and 127 metabolites, and 328 and 220 lipids in whole cells and the mito-ER fractions, respectively, along with partial least-squares-discriminant analysis (PLS-DA) models being systematically highly predictive of the disease. The most discriminant metabolomic features were the alteration of purine, pyrimidine, and energetic metabolisms, suggestive of oxidative stress and of pro-inflammatory status. The most important lipidomic feature in the mito-ER fraction was the disturbance of phosphatidylcholine PC (36:4p) levels, which we had previously reported in the cerebrospinal fluid of ALS patients and in the brain from an ALS mouse model. Thus, our results reveal that fibroblasts from sporadic ALS patients share common metabolic remodeling, consistent with other metabolic studies performed in ALS, opening perspectives for further exploration in this cellular model in ALS

Mammalian intestinal allometry, phylogeny, trophic level and climate

An often-stated ecomorphological assumption that has the status of ‘textbook knowledge’ is that the dimensions of the digestive tract correlate with diet, where herbivores – consuming diets of lower digestibility – have longer intestinal tracts than faunivores – consuming diets of higher digestibility. However, statistical approaches have so far failed to demonstrate this link. Here, we collated data on the length of intestinal sections and body mass of mammal species, and test for various relationships with trophic, climatic and other biological characteristics. All models showed a strong phylogenetic signal. Scaling relationships with body mass showed positive allometry at exponents >0.33, except for the caecum, which is particularly large in smaller species. Body mass was more tightly linked to small intestine than to large intestine length. Adding a diet proxy to the relationships increased model fit for all intestinal sections, except for the small intestine when accounting for phylogeny. Thus, diet has a main effect on the components of the large intestine, with longer measures in herbivores. Additionally, measures of habitat aridity had a positive relationship with large intestine length. The small intestine was longer in species from colder habitats at higher latitudes, possibly facilitating the processing of peak intake rates during the growing season. This study corroborates intuitive expectations on digestive tract anatomy, while the dependence of significant results on large sample sizes and inclusion of specific taxonomic groups indicates that the relationships cannot be considered fixed biological laws

Less need for differentiation? Intestinal length of reptiles as compared to mammals

Although relationships between intestinal morphology between trophic groups in reptiles are widely assumed and represent a cornerstone of ecomorphological narratives, few comparative approaches actually tested this hypothesis on a larger scale. We collected data on lengths of intestinal sections of 205 reptile species for which either body mass (BM), snout-vent-length (SVL) or carapax length (CL) was recorded, transforming SVL or CL into BM if the latter was not given, and analyzed scaling patterns with BM and SVL, accounting for phylogeny, comparing three trophic guilds (faunivores, omnivores, herbivores), and comparing with a mammal dataset. Length-BM relationships in reptiles were stronger for the small than the large intestine, suggesting that for the latter, additional factors might be relevant. Adding trophic level did not consistently improve model fit; only when controlling for phylogeny, models indicated a longer large intestine in herbivores, due to a corresponding pattern in lizards. Trophic level effects were highly susceptible to sample sizes, and not considered strong. Models that linked BM to intestine length had better support than models using SVL, due to the deviating body shape of snakes. At comparable BM, reptiles had shorter intestines than mammals. While the latter finding corresponds to findings of lower tissue masses for the digestive tract and other organs in reptiles as well as our understanding of differences in energetic requirements between the classes, they raise the hitherto unanswered question what it is that reptiles of similar BM have more than mammals. A lesser effect of trophic level on intestine lengths in reptiles compared to mammals may stem from lesser selective pressures on differentiation between trophic guilds, related to the generally lower food intake and different movement patterns of reptiles, which may not similarly escalate evolutionary arms races tuned to optimal agility as between mammalian predators and prey