Preferences, Norms and Constraints in farmers' agro-ecological choices. Case study using choice experiments survey in the Rhone River Delta, France

The aim of this paper is to elicit the sensitivity of farmers to payment for agro-environmental services in a context of strong ecological and policy constraints. We present results from a choice experiment survey performed among the whole population of agricultural decision-makers (104) in the Camargue area. Several econometric models have been estimated, the most significant being the Latent Classes one. Three classes have been identified, two of them representing farmers with strong committment to a specified technology (either very chemicals intensive or organic farming ), the main class encompassing farmers complying with the norms of the PGI « Riz de Camargue » . The estimated parameters of the utility function, together with the parameter of the monetary attribute provided the monetary value of each relevant agro-ecological attribute and the associated outcomes (average and risk yield). Outcomes of the choice experiments make a strong case for differentiating incentives for spreading environmental friendly technologies.

The Economic Determinants of the On-farm Management of Rice Cultivars in the Rhone River Delta (France)

The aims of our paper are to identify economic determinants of the on-farm cultivars diversity and to empirically characterize the farmers' diversification choices. We focus on the private decision making process involving the choice of rice cultivars and the corresponding allocation of farmland. For a specific crop, the choice of cultivars, and the resulting cultivars portfolio, involves the farmer comparing benefits and costs. Among the many costs involved, we focus on diversity's management costs. Our results rely on original data collected during the spring 2009 in the study area, and involve a sample of 86 economic units growing rice. We estimated a count data model, in which the endogeneous variable is the number of cultivars grown on the farm. After that, we studied the factors explaining the portfolio choice in terms of commercial rice grain, and the on-farm repartition between these different types. A multinomial logit model was used, with three alternatives, be specialized into a particular type of rice grain (long or round), or grow simultaneously these two types, or finally be diversified with niche market varieties. And finally we estimated the percentage of long rice compared to the percentage of round rice with a linear regression model. The results confirm the importance of the interactions between market related benefit and the management constraints on land and labor.varietal diversity, rice cultivar, multinomial logit, Agribusiness, Agricultural and Food Policy, Crop Production/Industries, Environmental Economics and Policy, Land Economics/Use, Production Economics,

De la littérature latine à la littérature française : une transition victime du cloisonnement académique

International audienceLes premiers poèmes vernaculaires mis par écrit nous offrent déjà quelques chefs-d’œuvre de notre littérature, que ce soit dans le domaine hagiographique (Vie de saint Alexis), épique (Chanson de Roland) ou lyrique (œuvre de Guillaume IX d’Aquitaine). Leur caractère élaboré a poussé les médiévistes à interroger leur genèse, notamment à travers la culture écrite latine du XIe siècle. Alors que cet angle de recherche est loin d’avoir porté tous ses fruits, il est aujourd’hui délaissé, victime des divisions disciplinaires et méthodologiques, ce qui n’est pas sans conséquence sur l’enseignement. Le présent article expose les différents cloisonnements universitaires qui entravent l’étude de la littérature médio-latine comme littérature de transition, mais aussi quelques initiatives ayant réussi à les dépasser. Il reviendra sur la motivation de la mise par écrit de la première littérature française puis sur la tradition littéraire et l’horizon d’attente dans laquelle elle s’inscrit, afin d’envisager les bases d’un indispensable questionnement pluridisciplinaire

Exactness of the Bogoliubov approximation in random external potentials

We investigate the validity of the Bogoliubov c-number approximation in the case of interacting Bose-gas in a \textit{homogeneous random} media. To take into account the possible occurence of type III generalized Bose-Einstein condensation (i.e. the occurrence of condensation in an infinitesimal band of low kinetic energy modes without macroscopic occupation of any of them) we generalize the c-number substitution procedure to this band of modes with low momentum. We show that, as in the case of the one-mode condensation for translation-invariant interacting systems, this procedure has no effect on the exact value of the pressure in the thermodynamic limit, assuming that the c-numbers are chosen according to a suitable variational principle. We then discuss the relation between these c-numbers and the (total) density of the condensate

Thermal-structural combined loads design criteria study

A study was conducted to determine methodology for combining thermal structural loads and assessing the effects of the combined loads on the design of a thermal protection system and a hot structure of a high cross range delta wing space shuttle orbiter vehicle. The study presents guidelines for establishing a basis for predicting thermal and pressure environments and for determining limit and ultimate design loads on the vehicle during reentry. Limit trajectories were determined by using dispersions on a representative nominal mission and system parameters expected during the life of the vehicle. Nine chosen locations on the vehicle surface having TPS or hot structures were examined, and weight sensitivity analyses were performed for each location

On the nature of Bose-Einstein condensation enhanced by localization

In a previous paper we established that for the perfect Bose gas and the mean-field Bose gas with an external random or weak potential, whenever there is generalized Bose-Einstein condensation in the eigenstates of the single particle Hamiltonian, there is also generalized condensation in the kinetic energy states. In these cases Bose-Einstein condensation is produced or enhanced by the external potential. In the present paper we establish a criterion for the absence of condensation in single kinetic energy states and prove that this criterion is satisfied for a class of random potentials and weak potentials. This means that the condensate is spread over an infinite number of states with low kinetic energy without any of them being macroscopically occupied

The real spectrum and the oriented Gromov--Hausdorff compactifications of character varieties

The character variety, which parametrizes reductive representations of finitely generated groups in $\mathrm{PSL}_2(\mathbb{R})$, has many compactifications. We construct a continuous surjection from the real spectrum compactification to the oriented Gromov--Hausdorff compactification of the character variety. For this purpose, we assign an orientation to the real trees appearing in the boundary of the real spectrum compactification using that the usual orientation on the circle is described by a semi-algebraic equation. Moreover, we show that the orientation on the real trees which appear in the boundary of both compactifications are well understood by the study of sequences within the character variety that converge toward the points in the boundary.Comment: 17 pages, comments are welcome

Impact of Preoperative Bevacizumab on Complications After Resection of Colorectal Liver Metastases: Case-Matched Control Study

Background: Chemotherapy may increase postoperative morbidity and mortality after liver surgery. Especially bevacizumab, a monoclonal antibody against vascular endothelial growth factor (VEGF), could have a detrimental effect. To assess the impact of neoadjuvant bevacizumab on clinical outcome after hepatectomy for colorectal liver metastases (CRLMs) this case-matched control study was initiated. Methods: The multicentric data collection was performed in the Swiss HPB Center of the University Hospital Zurich (CH), the Department of Digestive Surgery and Transplantation Strasbourg (F), and the Division of Hepato-biliary-pancreatic surgery of "Josep Tureta” Hospital Girona (E). Consecutive patients operated onbetween July 2005 and December 2007 due to CRLMs who received neoadjuvant chemotherapy were assessed. Patients were divided in two groups: group A had neoadjuvant chemotherapy with bevacicumab, and group B had it without bevacizumab. Results: No differences in overall morbidity (56 vs. 40% in the bevacizumab and control groups, respectively, p=0.23) or mortality could be documented. Similarly, the incidence of severe postoperative complications was not statistically different between the bevacizumab and control groups (31 and 18%, respectively, p=0.31). Wound complications were comparable (11% in the bevacizumab group compared and 9% in the control group, p=1.00). However, bevacizumab was associated with a significantly decreased incidence of postoperative hepatic insufficiency (7 vs. 20%, p=0.03). Conclusions: No impact on the incidence or severity of complications by bevacizumab could be shown. Bevacizumab may even reduce the incidence of liver failure after liver surger

Qualitative and quantitative analysis of the cannabinoid content of combusted cannabis plant tissue

Marihuana continues to be a controversial topic in today’s society. The plant material is used recreationally as a stupefacient and has a purported medicinal use. In fact, anecdotal information about its medicinal properties has been such that Health Canada has recently started an initiative to provide a well characterized supply of plant tissue to researchers interested in examining its potential medicinal properties. Simultaneously this same material is being provided for those subjects who are licensed to use marihuana as a medicine. In order to further study marihuana and its component cannabinoids it is essential to be able to discern both the cannabinoid content in the product being supplied and more importantly the cannabinoid profile in the delivery system. At present the most common route of administration is via inhalation of the combusted plant material. Consequently methods capable of measuring the cannabinoid content in combusted plant material would be very useful in order to make meaningful study of the pharmacokinetics of the cannabinoids delivered by this route. Investigations were carried out to develop a method and study the volatile constituents of combusted marihuana plant material in a semi-enclosed environment. Thus the hypothesis of this research is that qualitative and quantitative information can be obtained from the combustion products of cannabis plant tissue. The method relies upon the solid phase extraction of smoke arising from the combustion of plant material in a variety of combustion chambers. The combustion chambers were designed to reflect the current marihuana “paraphernalia” in use as well as a high efficiency in vitro system. Both the qualitative and quantitative levels of a limited number of cannabinoids were evaluated before and after combustion. A quantitative Liquid Chromatography Ultra Violet (LC-UV) detector method was validated for the analysis of a selected group of cannabinoids ( Δ9-tetrahydrocannabinol (THC), cannabinol (CBN), cannabidiol (CBD) and tetrahydrocannabinolic acid (THCA) . When this method was applied to plant material available through the medical marijuana initiative the following observations were made on the combustion products: Material CBD CBN THC THCA Analyzed (ug/ml) (ug/ml) (ug/ml) (ug/ml) Plant BLQ BLQ BLQ 890 Combusted 20 14 420 28 •5 mg plant tissue extracted using a validated HPLC-UV method •5 mg plant tissue combusted in a closed combustion chamber. •BLQ: below level of quantification

Static and wind tunnel near-field/far-field jet noise measurements from model scale single-flow baseline and suppressor nozzles. Volume 1: Noise source locations and extrapolation of static free-field jet noise data

A test was conducted in the Boeing Large Anechoic Chamber to determine static jet noise source locations of six baseline and suppressor nozzle models, and establish a technique for extrapolating near field data into the far field. The test covered nozzle pressure ratios from 1.44 to 2.25 and jet velocities from 412 to 594 m/s at a total temperature of 844 K