Estimating a production function under production and price risks: An application to the suckler cow farms in the French charolais production area

Suckler cow production in France relies mainly on a relatively extensive management of forage, implying that production risk may be enhanced by the sensitivity of those crops to weather variability. However risk exposure is supposed to be mitigated either through ex-ante decisions concerning pasture area management or through ex-post decisions concerning the purchase of feeds. This paper aims at assessing weather impacts on cattle production level decisions. Since farmers' decisions depend on farmers' behaviour regarding risks, which are namely production and price risks, we test constant absolute risk aversion, constant relative risk aversion and risk neutrality assumptions. We develop an econometric model encompassing an auto-regressive price function and a production function which allow inputs to affect independently mean and variance of the production. Weather indicators embodied by average regional forage production for current and past years are explicitely introduced as non controllable inputs. The estimation framework consist in conditions on the first and second moment of output production, output price and profit. Following, ISIK (2003), additional condition on each of both allocable inputs enable us to take into account risk aversion and both price and production risks in parameters estimation. We use the Generalized Method of Moments in order to make minimum assumptions regarding variable exogeneity and error distribution. We apply the model to an original panel dataset containing 65 individual yearly observations recorded over the period 1987-2005 on French suckler cow farms of the north of Massif Central. Because of the difficulties to find a relevant set of instruments, these preliminary results do not analyse weather impact on production mean. However we can advance that production decisions depend on price and production risks as farmers are found to be risk averse. Weather variability of the current year increase production risk whereas fertilizer level application slightly increased it. However we did not highlight that weather impact depend on production level.Production function estimation, GMM, weather impact, price and production risks, risk aversion, suckler cow farms, French charolais production area, Livestock Production/Industries, Production Economics,

Estimating a Production Function under Production and Output Price Risks: An Application to Beef Cattle in France

This paper addresses the issue of agricultural production under both output level and output price risks, in a context of random climatic conditions affecting forage used in beef production. It contributes to the empirical literature by applying the framework proposed by Isik (2002) to derive estimating equations from a structural production model with two sources of risks. Flexible functional forms for risk preferences and production technology allow us to identify attitudes toward risk and compute marginal effects of inputs and climate on expected output and production risk. The model is applied on a panel of French cattle farms and estimation results suggest that cattle farmer exhibit strong risk aversion of the CRRA form, and that climate has a significant impact on the performance of animal feeding strategies

Estimating a Production Function under Production and Output Price Risks: An Application to Beef Cattle in France

This paper addresses the issue of agricultural production under both output level and output price risks, in a context of random climatic conditions affecting forage used in beef production. It contributes to the empirical literature by applying the framework proposed by Isik (2002) to derive estimating equations from a structural production model with two sources of risks. Flexible functional forms for risk preferences and production technology allow us to identify attitudes toward risk and compute marginal effects of inputs and climate on expected output and production risk. The model is applied on a panel of French cattle farms and estimation results suggest that cattle farmer exhibit strong risk aversion of the CRRA form, and that climate has a significant impact on the performance of animal feeding strategies

Design of a 5 GeV laser–plasma accelerating module in the quasi-linear regime

International audienceMulti-GeV-class laser–plasma accelerating modules are key components of laser–plasma accelerators, because they can be used as a booster of an upstream plasma or conventional injector or as modular acceleration sections of a multi-staged high energy plasma linac. Such a plasma module, operating in the quasi-linear regime, has been designed for the 5 GeV laser–plasma accelerator stage (LPAS) of the EuPRAXIA project. The laser pulse ( ∼ 150 TW, ∼ 15 J) is quasi-matched into a plasma channel ( np=1.5×1017 cm −3 , L∼ 30 cm) and the bi-Gaussian electron beam is externally injected into the wakefield. The beam emittance is preserved through the acceleration by matching the beam size to the transverse focusing fields. And a final energy spread of < 1% has been achieved by optimizing the beam loading effect. Several methods have been proposed to reduce the slice energy spread and are found to be effective. The simulations were conducted with the 3D PIC code Warp in the Lorentz boosted frame

Slice Energy Spread Optimization for a 5 GeV Laser-Plasma Accelerator

International audienceGeV-scale laser-plasma accelerating modules can be integrated into a multi-staged plasma linac for driving compact X-ray light sources or future colliders. Such a plasma module, operating in the quasi-linear regime, has been designed for the 5 GeV laser plasma acceleration stage (LPAS) of the EuPRAXIA project. Although it can be employed to optimize the total energy spread, the beam loading effect introduces an non-negligible slice energy spread to the beam. In this paper, we study the slice energy spread from linear theory, establishing a relationship between it and the laser-plasma parameters. To reduce the slice energy spread, simulations have been carried out for various plasma densities and laser strengths. The results will be discussed and compared with the theory

Toward low energy spread in plasma accelerators in quasilinear regime

In this paper, we address the energy spread and slice energy spread of an externally injected electron beam in plasma wakefield accelerators operating in the linear or quasilinear regime. The energy spread is first derived taking into account the phase dependence of the wakefield along the finite-length bunch together with the dephasing during acceleration and found to be strongly dependent on the bunch length. This could be compensated by the beam loading effect, the energy spread from which is then derived and found to be nearly independent of the bunch length. However, the transverse dependence of the beam loading effect also makes the particles at the same longitudinal position experience different accelerating fields, introducing a significant slice energy spread. To estimate the slice energy spread, a theoretical analysis was conducted by taking the transverse betatron motion into account. As a study case, 3D simulations for the 5 GeV laser-plasma acceleration stage of the European Plasma Research Accelerator with eXcellence in Applications project have been performed. Careful optimization of the parameters allows one to obtain an energy spread of ≤1% and a slice energy spread of ≤0.1%, with good agreement between theories and simulations

Estimation économétrique d'une fonction de production et de l'attitude des éleveurs vis-à-vis des risques de prix et de production

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