Environmental Good Production in the Optimum Activities Portfolio of a Risk Averse Farmer

An analytical framework is proposed for analysis of environmental good production by farmers in the case of price uncertainty. Environmental good production contracted by means of agri-environmental agreements is treated as a risk less option in the farmer's production activities portfolio. Efficient frontiers were generated using mathematical programming farm level models of suckler cow farms in Monts du Cantal, in France. It was demonstrated that for a DARA risk averse farmer: 1) the agreement payment level is not without impact on the farming intensity on parcels not subscribed under the corresponding argi-environmental programme, 2) a lump sum payment matters under uncertainty, 3) the overall impact of the lump sum payment on environmental good production depends on the type of jointness in production of agricultural and environmental goods, and on the level of uncertainty.uncertainty, portfolio optimisation, biodiversity, agricultural policy, mathematical programming, Agricultural and Food Policy, Resource /Energy Economics and Policy, Q12, Q18, Q28,

Environmental good production in the optimum activities portfolio of a risk averse-farmer

An analytical framework is proposed for analysis of environmental good production by farmers in the case of price uncertainty. Environmental good production contracted by means of agri-environmental agreements is treated as a riskless option in the farmer’s production activities portfolio. It is shown that agri-environmental agreements aiming at biodiversity competing with beef production are likely to increase management intensity on the non-enrolled land, and that the effect of the payments for these agreements on the number of hectares enrolled is ambiguous. It is also demonstrated that an increase in the output price variability and/or a decrease in the level of decoupled subsidies will induce an increase (decrease) in the area enrolled in agreements aiming at biodiversity competing with (complementary to) beef production. The obtained results are illustrated by means of efficient frontiers generated using mathematical programming farm level models of suckler cow farms in Monts du Cantal, in France.uncertainty, portfolio optimisation, biodiversity, agricultural policy, mathematical programming

Attenuating through Aid the Vulnerability to Price Shocks

The purpose of this paper is to examine what kind of global measures may be efficiently implemented to help the developing countries to face price shocks, avoiding the past failures, which needs to take into account the long term trend of the markets. Firstly, we recall the nature of the vulnerability to price shocks: this legitimates to make the dampening of these shocks a reasonable goal for the development cooperation policy. Then, we consider the rationality of some international schemes of insurance or of guarantee which could be implemented through international assistance for countries facing price shocks: this assistance should be provided on a macroeconomic level, in particular through debt management, and on a microeconomic level, for instance through an insurance for the producers. The general principle underlying our proposals is that international assistance can enable developing countries to face price shocks, while taking into account the market signals, by offering a guarantee to these countries provided they respect some management rules.

Incidence, severity, mortality, and confounding factors for dissecting AAA detection in angiotensin II-infused mice: a meta-analysis

Aims While angiotensin II-infused mice are the most popular model for preclinical aneurysm research, representative data on incidence, severity, and mortality of dissecting abdominal aortic aneurysms (AAAs) have never been established, and the influence of confounding factors is unknown. Methods and Results We performed a meta-analysis including 194 manuscripts representing 1679 saline-infused, 4729 non-treated angiotensin II-infused, and 4057 treated angiotensin II-infused mice. Incidence (60%) and mortality (20%) rates are reported overall as well as for grade I (22%), grade II (26%), grade III (29%), and grade IV (24%) aneurysms. Dissecting AAA incidence was significantly (P < 0.05) influenced by sex, age, genetic background, infusion time, and dose of angiotensin II. Mortality was influenced by sex, genetic background, and dose, but not by age or infusion time. Surprisingly, both incidence and mortality were significantly different (P < 0.05) when comparing angiotensin II-infused mice in descriptive studies (56% incidence and 19% mortality) with angiotensin II-infused mice that served as control animals in treatment studies designed to either enhance (35% incidence and 13% mortality) or reduce (73% incidence and 25% mortality) dissecting AAA formation. After stratification to account for confounding factors (selection bias), the observed effect was still present for incidence, but not for mortality. Possible underlying causes are detection bias (non-uniform definition for detection and quantification of dissecting AAA in mice) or publication bias (studies with negative results, related to incidence in the control group, not being published). Conclusions Our data provide a new meta-analysis-based reference for incidence and mortality of dissecting AAA in angiotensin II-infused mice, and indicate that treatment studies using this mouse model should be interpreted with cautio

Selection for reduced muscle glycolytic potential in Large White pigs. II. Correlated responses in meat quality and muscle compositional traits

International audienc

Dispositif ultra-léger de caractérisation mécanique de la peau humaine in vivo en extensiométrie uniaxiale (S13)

L'étude des propriétés mécaniques de la peau humaine in vivo est une étape utile dans l'optimisation des interventions chirurgicales. Pour évaluer les caractéristiques de ce tissu biologique complexe, un dispositif a été développé au sein de l'institut FEMTO-ST, il est composé d'un extensiomètre ultra-léger piloté par une application, elle-même comportant un éditeur de consigne ainsi qu'une interface de commande. Afin de valider ce dispositif, des tests ont été réalisés pour obtenir la réponse de celui-ci à différents types de sollicitations en extension uniaxiale, ainsi qu'une comparaison avec la réponse obtenue d'une machine de traction standard. Cette comparaison a montré une forte similarité entre les deux appareils de mesure. Grâce à sa taille, son poids et sa portabilité, le dispositif présenté a mis en évidence le comportement hyperélastique et visqueux du tissu cutané lors de tests réalisés in vivo en différentes localisations corporelles.   The analysis of the mechanical properties of human skin in vivo is an essential parameter for the optimization of surgical operations in terms of cutaneous tissues. This paper presents an experimental device that was developed at FEMTO-ST institute for evaluating the skin response to different loadings. The ultra-light extensometer developed was tested in a uniaxial extension on a phantom material. The results obtained were successfully compared with those of a conventional tensile test device. The user-friendly interface allows the definition of diverse load and discharge sequences. The results of the tests on human subjects are consistent with the hyperelastic and viscous behavior of the cutaneous tissue in vivo. Thanks to its size, weight and stand-alone capabilities, the device is suited for local measurements in most of human body zones. This study provides an experimental tool for investigating human skin behavior in vivo. Further researches are being directed towards identifying the strain fields of human skin by means of a biaxial extensometer and an imaging module

A model for simulating structure-function relationships in walnut tree growth processes.

An ecophysiological growth process model, called INCA, for simulating the growth and development of a young walnut tree (Juglans regia L.) during three or four years, is presented. This tool, currently under development, aims at integrating architectural and physiological knowledge of the processes involved, in order to give a more rational understanding of the pruning operation. The model describes a simple three-dimensional representation of tree crown, solar radiation interception, photosynthesis, respiration, growth and partitioning of assimilates to leaves, stems, branches and roots. It supports the hypothesis that the tree grows as a collection of semiautonomous, interacting organs that compete for resources, based on daily sink strengths and proximity to sources. The actual growth rate of organs is not predetermined by empirical data, but reflects the pattern of available resources. The major driving variables are solar radiation, temperature, topological, geometrical and physiological factors. Outputs are hourly and daily photosynthate production and respiration, daily dimensional growth, starch storage, biomass production and total number of different types of organ. The user can interact or override any or all of the input variables to examine the effects of such changes on photosynthate production and growth. Within INCA, the tree entities and the surrounding environment are structured in a frame-based representation whereas the processes are coded in a rule-based language. The simulation mechanism is primarily based on the rule chaining capabilities of an inference engine