Veal calf industry economics

This paper provides an outline of the veal industry, its standing relative to other cattle farming enterprises, and its future prospects. In 2008 some 20 per cent of bovines slaughtered in the EU were for veal production and about one-third of them were dairy calves. France, the Netherlands and Italy were Europe’s leading producers. Veal consumption in the European Union has been in steady decline since 1970. In 2008, it averaged 1.6 kg per capita, with France and Italy being the largest consumers. Despite variations in farming systems and carcass characteristics from one country to another, veal production is an important outlet for milk replacer producers and provides a market for their industrial dairy products. Regular changes in production factors such as the price of 8-day-old calves and milk replacers and their availability engender recurrent output fluctuations. Veal calf production plays a major part in regulating the milk and bovine-meat markets: it has largely contributed to stemming dairy (and sometimes meat) surpluses. However, the context has changed since 2008 with no more surplus milk supply and reduced EU-support for incorporating skimmed milk powder into milk feeds. Therefore, the relative attractiveness of other productions using 8-day-old calves and the support policies for cattle farming as a whole will affect the future of the veal calf industry

Nakajima varieties and repetitive algebras

We realize certain graded Nakajima varieties of finite Dynkin type as orbit closures of repetitive algebras of Dynkin quivers. As an application, we obtain that the perverse sheaves introduced by Nakajima for describing irreducible characters of quantum loop algebras are isomorphic to the intersection cohomology sheaves of these orbit closures.Comment: 26 pages, v2 : Minor corrections. Final version to appear in PRIMS (Publications of the Research Institute for Mathematical Sciences, Kyoto

Price decomposition in large-scale stochastic optimal control

We are interested in optimally driving a dynamical system that can be influenced by exogenous noises. This is generally called a Stochastic Optimal Control (SOC) problem and the Dynamic Programming (DP) principle is the natural way of solving it. Unfortunately, DP faces the so-called curse of dimensionality: the complexity of solving DP equations grows exponentially with the dimension of the information variable that is sufficient to take optimal decisions (the state variable). For a large class of SOC problems, which includes important practical problems, we propose an original way of obtaining strategies to drive the system. The algorithm we introduce is based on Lagrangian relaxation, of which the application to decomposition is well-known in the deterministic framework. However, its application to such closed-loop problems is not straightforward and an additional statistical approximation concerning the dual process is needed. We give a convergence proof, that derives directly from classical results concerning duality in optimization, and enlghten the error made by our approximation. Numerical results are also provided, on a large-scale SOC problem. This idea extends the original DADP algorithm that was presented by Barty, Carpentier and Girardeau (2010)

Optimal Taxation and Monopsonistic Labor Market: Does Monopsony justify the Minimum Wage?

Does monopsony on the labor market in itself justify the implementation of a minimum wage when it would not be used in a competitive economy? This issue is studied in a model of optimal taxation. We adopt a definition most favorable to the minimum wage: the minimum wage is useful whenever it can replace a non negligible part of the tax schedule. The minimum wage is useful to correct the inefficiencies associated with the monopsony when there is a single skill. But the minimum wage is not useful any more when there are a continuum of skills.Minimum wage, Optimal taxation, Monopsony.

A spatial interpretation of emerging superconductivity in lightly doped cuprates

The formation of domains comprising alternating 'hole rich' and 'hole poor' ladders recently observed by Scanning Tunneling Microscopy by Kohsaka et al., on lightly hole doped cuprates, is interpreted in terms of an attractive mechanism which favors the presence of doped holes on Cu sites located each on one side of an oxygen atom. This mechanism leads to a geometrical pattern of alternating hole-rich and hole-poor ladders with a periodicity equal to 4 times the lattice spacing in the CuO plane, as observed experimentally. To cite this article: G. Deutscher, P.-G. de Gennes, C. R. Physique 8 (2007).Comment: 4 pages, 3 figuer