Piecemeal Oligopoly, Exchange Rate Uncertainty, and Trade Policy

RESUMEN:Este artículo analiza el efecto sistemático de la volatilidad de la tasa de cambio, cuando un gobierno local debe evaluar políticas comerciales estratégicas lineales y cuadráticas. Este ejercicio se realiza para modelosde mercado Cournot y Bertran. El modelo prueba que tanto el esquema lineal como el cuadrático tienen el mismo efecto sobre el bienestar social de los paises, y que la volatilidad de la tasa de cambio doméstica lleva a los gobiernos a reducir los subsidios a las exportaciones o bajan los impuestos a las exportaciones, de acuerdo a la variable estratégica elegida por las firmas. La tasa de cambio extrangera tiene diferentes efectos dependiendo de si las firmas producen bajos rendimientos a escalas constantes o decrecientes.ABSTRACT:This paper examines the systematic effect of the exchange rate volatility, when a local government has to evaluate linear and quadratic strategic trade policies. The exercise is realized for both Cournot and Bertrand markets fashions. The model proves that the linear or quadratic scheme have the same effect on the countries´ social welfare, and that the volatility of the domestic exchange rate leads governments to reduce export subsidies or to cutexport taxes, according to the strategic variable chosen by firms. The foreignexchange rate volatility has different effects if firms produce under constantreturn or decreasing return of scale.Comercio, Estructuras de Mercado y de Precios, Estrategia de Firma, Información e Incertidumbre.

Labour market, international trade, and unemployment in a less developed country

This paper constructs a trade general equilibrium model for a less developed country with three sectors. One is the informal and un-tradable sector characterized by flexible wages, while the other two sectors are tradable, export and import sectors. The model imposes a binding minimum wage over the unskilled labour and efficient wage distortions on the skilled labour. Comparative statics is driven to analyze the effects on the labour market as consequence of opening the economy, raising the minimum wage and the introduction of an augmenting productivity in the export sector.Trade reforms; Trade and labor markets interactions, Demand for labor.

Técnica de Jackknife y estimadores en un modelo lineal

En este artículo estudiamos los efectos que tiene el utilizar esta técnica en estimadores eficientes, pero sesgados de un vector de parámetros en modelos lineales, buscando reducir el sesgo sin perder la eficiencia de estos estimadores.In this article study this technique effects over efficient estimators but in skew vectors in linear model parameters so reducing the skew without losing the estimators efficiency

Sistemas de telefonía por satélite : la extinción de fronteras

Peer Reviewe

Sistemas de telefonía por satélite : la extinción de fronteras

Peer Reviewe

Hidden Markov Models for Gene Sequence Classification: Classifying the VSG genes in the Trypanosoma brucei Genome

The article presents an application of Hidden Markov Models (HMMs) for pattern recognition on genome sequences. We apply HMM for identifying genes encoding the Variant Surface Glycoprotein (VSG) in the genomes of Trypanosoma brucei (T. brucei) and other African trypanosomes. These are parasitic protozoa causative agents of sleeping sickness and several diseases in domestic and wild animals. These parasites have a peculiar strategy to evade the host's immune system that consists in periodically changing their predominant cellular surface protein (VSG). The motivation for using patterns recognition methods to identify these genes, instead of traditional homology based ones, is that the levels of sequence identity (amino acid and DNA sequence) amongst these genes is often below of what is considered reliable in these methods. Among pattern recognition approaches, HMM are particularly suitable to tackle this problem because they can handle more naturally the determination of gene edges. We evaluate the performance of the model using different number of states in the Markov model, as well as several performance metrics. The model is applied using public genomic data. Our empirical results show that the VSG genes on T. brucei can be safely identified (high sensitivity and low rate of false positives) using HMM.Comment: Accepted article in July, 2015 in Pattern Analysis and Applications, Springer. The article contains 23 pages, 4 figures, 8 tables and 51 reference

High temperature behavior of calcium aluminate cement pastes

ABSTRACT: Calcium aluminate cements (CAC) are important materials today, as they cover a good number of applications in civil engineering, refractory industry and materials science, which is mainly due to their excellent high temperature mechanical properties, strength to corrosion, erosion wear, among others. The inherent brittleness and lack of ductility of these cements, particularly make them susceptible to failures mainly by thermal shock and slow outflow. In order to understand and elucidate the micro mechanisms that govern outflow damages and / or high temperatures, it is necessary to know the high temperature behavior of calcium aluminate cement pastes, the transformations of their phases, and their types and mechanisms of damage, complex phenomena related to factors such as chemical composition, water / cement ratio and alumina content. Calcium aluminate cements are the basis for the manufacture of many refractory ceramics, advanced ceramics, and functional materials with gradients used in many different applications. Therefore, this proposal is intended to contribute to the understanding of the behavior of pure calcium aluminate cement paste and added with silica, for different alumina contents, subjected to high temperatures and using different water/cement ratio (W/C). In order to improve knowledge in this topic, once the calcium aluminate cement paste samples have been manufactured, they were exposed to high temperatures and analyzed using techniques such as scanning electron microscopy, infrared transformation spectroscopy of Fourier, X-ray diffraction, X-ray fluorescence, among others. Then, to be able to establish mathematical models that allow the damage to be quantified and the micro-mechanisms that govern this behavior to be revealed

Efectos de la crisis económica en la contratación en defensa

La contratación en el ámbito de la defensa posee una especial importancia debido a que es uno de los ministerios con mayor volumen de gasto e inversión. Los efectos de la crisis económica, en sus primeros años, se dejaron notar especialmente a través de importantes reducciones presupuestarias que conllevaron cambios de calado en las formas de contratación y en su orientación tecnológica. Este artículo analiza más de 3.000 contratos en 2008 y 2011, mostrando los aspectos en los cuales se han centrado los principales cambios en este ámbito

Estudio de desgaste de láminas de acero deformadas con herramientas recubiertas

Los recubrimientos duros han sido ampliamente utilizados en la industria metalmecánica para la protección de las superficies de las herramientas debido a las propiedades de las capas como baja fricción y alta resistencia al desgaste, siendo estos tratamientos superficiales adecuados para disminuir los costos en la industria. De acuerdo a esto, esta investigación se enfoca en el análisis de láminas de acero AISI 1045 deformadas con herramientas de conformado recubiertas con nitruro de titanio aluminio (TiAlN) depositados por la técnica Magnetrón Sputtering Tríodo. El análisis  se realiza a partir de las propiedades superficiales y químico que influyen directamente en el comportamiento tribológic