Typification and economic analysis of beef-producing farms in Spain

In spite of different economic agents’ interests, as well as the Administration’s effort in promoting extensive beef-producing systems over the last years, this kind of activity still hasn’t reached the desirable levels, being necessary that farmers perceive an appropriate benefit which supports their activity. In this sense, this paper, using the data obtained by a statistical survey representing all the extensive beef-producing farms existing in Castile and Leon (Spain), aims to analyze the economical results of extensive beef-producing farms, previously classified in representative groups according a quantitative method. The study is a preliminary research which intends to generate additional knowledge about the role of the different variables which make part of the economic results, and takes part of a research project financed by Castile and Leon Regional Governments, Education and Culture Council, through the annual program to support research projects (Order EDU/1143/2004).Cluster Analysis, extensive beef producing systems, economic accounts, Livestock Production/Industries,

Fluid-solid transition in hard hyper-sphere systems

In this work we present a numerical study, based on molecular dynamics simulations, to estimate the freezing point of hard spheres and hypersphere systems in dimension D = 4, 5, 6 and 7. We have studied the changes of the Radial Distribution Function (RDF) as a function of density in the coexistence region. We started our simulations from crystalline states with densities above the melting point, and moved down to densities in the liquid state below the freezing point. For all the examined dimensions (including D = 3) it was observed that the height of the first minimum of the RDF changes in an almost continuous way around the freezing density and resembles a second order phase transition. With these results we propose a numerical method to estimate the freezing point as a function of the dimension D using numerical fits and semiempirical approaches. We find that the estimated values of the freezing point are very close to previously reported values from simulations and theoretical approaches up to D = 6 reinforcing the validity of the proposed method. This was also applied to numerical simulations for D = 7 giving new estimations of the freezing point for this dimensionality.Comment: 13 pages, 10 figure