First order signatures in 4D pure compact U(1) gauge theory with toroidal and spherical topologies

We study the pure compact U(1) gauge theory with the extended Wilson action (\beta, \gamma couplings) by finite size scaling techniques, in lattices ranging from L=6 to L=24 in the region of \gamma <= 0 with toroidal and spherical topologies. The phase transition presents a double peak structure which survives in the thermodynamical limit in the torus. In the sphere the evidence support the idea of a weaker, but still first order, phase transition. For negative values of gamma the transition becomes weaker and larger lattices are needed to find its asymptotic behaviour. Along the transient region the behaviour is the typical one of a weak first order transition for both topologies, with a region where 1/d < nu < 0.5, which becomes nu compatible with 1/d when larger lattices are used.Comment: Some references added; changes in the text mainly wording. To appear in Phys. Lett.

Productive Efficiency in 16 European Countries

We investigate in this paper differences in productive efficiency across sixteen European countries. In order to assess differences in productive efficiency, we have built a dynamic input-output model and computed for each country the balanced growth rate and the balanced output composition. After that, we investigate how the differences existing between the output composition for balanced growth and the actual one relate to the differences between the rate of balanced growth and the actual one. In the final part of the paper we examine the influence of individual sectors on the rate of balanced growth by looking for growth-sensitive sectors.Productive efficiency, input-output, growth, Europe

Study of the Coulomb-Higgs transition in the Abelian Higgs Model

The order of the Coulomb-Higgs transition in the U(1)-Higgs model with unfrozen modulus of the scalar field is studied. Large lattices (up to $24^4$ in one case) and high statistics are used. We fix $\beta =1.15$ and explore specially a region of $\lambda$-values where metastability is observed. We study the thermodynamical limit of several observables, in particular, the latent heat, the specific heat, the decrement of the free energy between the maxima and the central minimum of the two-peaked histogram, the Binder cumulant and the displacement of the critical coupling with the lattice size. The results point towards a second order transition for $\lambda \gtrsim 0.005$, while for smaller values of $\lambda$ the strong metastability growing with the lattice size seems to derive from a first order character.Comment: 10 pages, Latex, epsfig, uuencoded gzipped tar file, 4 figures include

A lattice Monte Carlo study of Inverse Symmetry Breaking in a two-scalar model in three dimensions

We carry a Monte Carlo study of the coupled two-scalar $\lambda\phi^2_1 \phi^2_2$ model in three dimensions. We find no trace of Inverse Symmetry Breaking in the region of negative $\lambda$'s for which the one-loop effective potential predicts this phenomenon. Moreover, for $\lambda$'s negative enough, but still in the stability region for the potential, one of the transitions turns out to be of first order, both for zero and finite temperature.Comment: 23 pages, 7 figures included, Latex, epsfig. Minor changes in Sec.3 and in the conclusions. In press on Nuc.Phys.

A proposal of a Renormalization Group transformation

We propose a family of renormalization group transformations characterized by free parameters that may be tuned in order to reduce the truncation effects. As a check we test them in the three dimensional XY model. The Schwinger--Dyson equations are used to study the renormalization group flow.Comment: Contribution to Lattice'94. uuencoded postscript fil

The U(1) phase transition on toroidal and spherical lattices

We have studied the properties of the phase transition in the U(1) compact pure gauge model paying special atention to the influence of the topology of the boundary conditions. From the behavior of the energy cumulants and the observation of an effective \nu -> 1/d on toroidal and spherical lattices, we conclude that the transition is first order.Comment: LATTICE98(gauge

Monte Carlo studies of antiferromagnetic spin models in three dimensions

We study several antiferromagnetic formulations of the O(3) spin model in three dimensions by means of Monte Carlo simulations. We discuss about the vacua properties and analyze the phase transitions. Using Finite Size Scaling analysis we conclude that all phase transitions found are of first orderComment: 4 pages, 2 Postscript figures. Contribution to Lattice '9

A multisite microcanonical updating method

We have made a study of several update algorithms using the XY model. We find that sequential local overrelaxation is not ergodic at the scale of typical Monte Carlo simulation time. We have introduced a new multisite microcanonical update method, which yields results compatible with those of random overrelaxation and the microcanonical demon algorithm, which are very much slower, all being incompatible with the sequential overrelaxation results.Comment: 13 pages, 4 figure

Investigación de mercados de un instrumento de análisis articular: un caso práctico

The launch of new products process must be based on market data that let make an entrance and communication strategy that will make decrease uncertainty. The main objective of this market research is to establish a suitable sales and communication strategy for an ankle analysis instrument. To reach the objective, a questionnaire was administered to 138 athletes and 130 physiotherapist. The results support a communication strategy based in a push model and a focused sales model, without necessity of segmentation by pay availability or age. We can conclude that this market research had the result expected, and helped to the creation of the right marketing strategies focused on the product-market fit.El proceso de lanzamiento de nuevos productos debe estar basado en datos del mercado que permitan realizar una estrategia de entrada y comunicación que permita minimizar al máximo la incertidumbre. El objetivo del trabajo fue realizar una investigación de mercados para establecer una estrategia de ventas y comunicación adecuada para un instrumento de análisis del tobillo. Para ello se administró un cuestionario a 138 deportistas y 130 fisioterapeutas. Los resultados sugieren realizar una estrategia de comunicación centrada en un modelo push y una estrategia de ventas concentrada, sin necesidad de segmentación por disponibilidad de pago por el producto o edad. Por lo que podemos concluir que esta investigación de mercados tuvo el resultado esperado, y ayudó a crear estrategias de marketing centradas en el encaje producto-cliente