TESTING COLLUSIVE PRICES IN A MULTIMARKET CONTEXT: THE EUROPEAN CASE OF VITAMIN C

In this paper, we suggest a method to test price-fixing agreements. Prices fixed to multiple shipments are decomposed into a set of destination market effects and time effects in order to allow us to perform an analysis of residuals. We examine the pricing behavior of vitamin C in the European destination markets of German exports. We explore two different periods: January 1991 to August 1995 and September 1995 to September 2001. Empirical results on the first period, which are consistent with our knowledge obtained from firms¿ confessions about illegal agreements, contrast notably with those obtained on the more recent period. En este trabajo proponemos un método para contrastar la presencia de prácticas no competitivas en precios. Cada uno de los precios fijados para diferentes mercados es descompuesto en un efecto fijo por destino y un efecto temporal con objeto de analizar los residuos. Los precios de la vitamina C en los mercados de destino de las exportaciones alemanas son examinados en dos periodos: de enero de 1991 a agosto de 1995 y de septiembre de 1995 a septiembre de 2001. Los resultados para el primer periodo, los cuales son consistentes con nuestro conocimiento obtenido de las confesiones de las empresas participantes en los acuerdos ilegales, contrastan notablemente con los obtenidos para un período más reciente.Colusión; Mercados internacionales; Vitamina C Collusion; International markets; Vitamin C

PRICING TO MARKET BEHAVIOR IN OLIGOPOLISTIC COMPETITION: A MICROECONOMETRIC APPROACH

This paper takes into account the presence of oligopolistic rivalry between exporters to evaluate their pricing to market behavior. We specify the pricing policy as a simultaneous equation model, which captures the effects of possible interactions in multiple destination markets. The use of information related to multiple transactions helps to alleviate the cost measurement problem found in the typical analyses on prices and exchange rates. Furthermore, the exogenous variations of the exporters' exchange rate vis-à-vis the currency of each destination market will enable us to identify the reaction functions. The empirical approach is applied to the European ceramic tiles industry, where Italian and Spanish exporters compete. Prices are strategic complements and the markup adjustments, caused directly by exchange rate variations, are amplified by the feedback effects on rival's prices. En este trabajo consideramos la presencia de rivalidad oligopolística entre exportadorescon objeto de evaluar la presencia de "pricing to market". Especificamos la política deprecios mediante un modelo de ecuaciones simultáneas que recoge los efectos de lasposibles interacciones existentes en múltiples mercados de destino de las exportaciones.El problema de estimación de costes, típico en el análisis de precios y tipos de cambio,se resuelve mediante el uso de información relativa a múltiples transacciones. Por otraparte, las variaciones exógenas del tipo de cambio de la moneda de los exportadoresfrente a la de cada mercado de destino permitirá identificar las funciones de reacción.La aproximación empírica obtenida se aplica a la industria europea de pavimentos yrevestimientos cerámicos en la que los exportadores españoles y italianos compiten. Losresultados indican que los precios actúan como complementarios estratégicos y que losajustes de márgenes de beneficio, causados directamente por las variaciones en los tiposde cambio, son amplificados por la retroalimentación existente sobre los precios de losrivales.tipos de cambio; funciones de reacción; "Pricing to market" Exchange rates; Reaction functions; Pricing to market

El capital social como instrumento del análisis económico

The relations between the economy and the culture is tried to be analyzed in this paper under the theorizing of the social capital, underlying the relevance of the cultural factors as the structural principle of the society and as another piece of the wealth of nations. The confidence stands out among these factors as the base of the modern economic process. An attempt of proving the influence that the social vision is having on the economic research over the last decades is carried out. This aim is tried by means of the establishment of this reality and its inclusion in the analysis of the economic development and the poverty eradication.Bajo la teorización del capital social se intenta analizar las vinculaciones entre economía y cultura, remarcando la trascendencia de los factores culturales como principio estructurador de la sociedad y una pieza más de la riqueza de las naciones. Entre estos factores se destaca la confianza como base de los procesos económicos modernos. A través de la conformación de esta realidad y de su inclusión en los análisis sobre el desarrollo económico y la erradicación de la pobreza, intentamos comprobar la influencia que en las últimas décadas está teniendo la visión social en la investigación económica

Cambio didáctico del profesorado de ciencias experimentales y filosofía de la ciencia

La comprensión de los procesos de cambio didáctico del profesorado, así como los aspectos que lo facilitan u obstaculizan, es uno de los temas más relevantes de la agenda internacional de investigación educativa, y un elemento esencial para planificar y llevar a cabo programas de formación inicial y permanente del profesorado. En el artículo revisamos las investigaciones sobre el cambio didáctico del profesorado de ciencias experimentales. Para organizar esta información establecemos una analogía con el proceso de cambio científico, según distintas teorías de la filosofía de la ciencia, analizando y valorando las aportaciones de los distintos modelos.One of the most important topics on the international agenda in educational research is to gain an understanding of the educational change processes in the teachers, as well as the factors that favour or hinder it. At the same time, it is an essential element for planning and putting into practice initial and ongoing teacher education programs. In this article we review the investigations on science teachers' educational change. In order to organize this information we establish an analogy with the process of scientific change, according to different theories from philosophy of science, analysing and valuing the contributions of the different models

Spike-based control monitoring and analysis with Address Event Representation

Neuromorphic engineering tries to mimic biological information processing. Address-Event Representation (AER) is a neuromorphic communication protocol for spiking neurons between different chips. We present a new way to drive robotic platforms using spiking neurons. We have simulated spiking control models for DC motors, and developed a mobile robot (Eddie) controlled only by spikes. We apply AER to the robot control, monitoring and measuring the spike activity inside the robot. The mobile robot is controlled by the AER-Robot tool, and the AER information is sent to a PC using the USBAERmini2 interface.Junta de Andalucía P06-TIC-01417Ministerio de Educación y Ciencia TEC2006-11730-C03-0

An AER-Based Actuator Interface for Controlling an Anthropomorphic Robotic Hand

Bio-Inspired and Neuro-Inspired systems or circuits are a relatively novel approaches to solve real problems by mimicking the biology in its efficient solutions. Robotic also tries to mimic the biology and more particularly the human body structure and efficiency of the muscles, bones, articulations, etc. Address-Event-Representation (AER) is a communication protocol for transferring asynchronous events between VLSI chips, originally developed for neuro-inspired processing systems (for example, image processing). Such systems may consist of a complicated hierarchical structure with many chips that transmit data among them in real time, while performing some processing (for example, convolutions). The information transmitted is a sequence of spikes coded using high speed digital buses. These multi-layer and multi-chip AER systems perform actually not only image processing, but also audio processing, filtering, learning, locomotion, etc. This paper present an AER interface for controlling an anthropomorphic robotic hand with a neuro-inspired system.Unión Europea IST-2001-34124 (CAVIAR)Ministerio de Ciencia y Tecnología TIC-2003-08164-C03-0

Fast Multipole Method for Gravitational Lensing: Application to High-magnification Quasar Microlensing

We introduce the use of the fast multipole method (FMM) to speed up gravitational lensing ray tracing calculations. The method allows very fast calculation of ray deflections when a large number of deflectors, N-*, are involved, while keeping rigorous control on the errors. In particular, we apply this method, in combination with the inverse polygon mapping (IPM) technique, to quasar microlensing to generate microlensing magnification maps with very high workloads (high magnification, large size, and/or high resolution) that require a very large number of deflectors. Using FMM-IPM, the computation time can be reduced by a factor of similar to 10(5) with respect to standard inverse ray shooting (IRS), making the use of this algorithm on a personal computer comparable to the use of standard IRS on GPUs. We also provide a flexible web interface for easy calculation of microlensing magnification maps using FMM-IPM (see https://gloton.ugr.es/microlensing/). We exemplify the power of this new method by applying it to some challenging interesting astrophysical scenarios, including clustered primordial black holes and extremely magnified stars close to the giant arcs of galaxy clusters. We also show the performance/use of FMM to calculate ray deflection for a halo resulting from cosmological simulations composed of a large number (N (sic) 10(7)) of elements.MCIN/AEI PID2020-118687GB-C33 PID2020-118687GB-C31Junta de Andalucia FQM-108, P20_00334 A-FQM-510-UGR20/FEDE

Synthetic retina for AER systems development

Neuromorphic engineering tries to mimic biology in information processing. Address-Event Representation (AER) is a neuromorphic communication protocol for spiking neurons between different layers. AER bio-inspired image sensor are called “retina”. This kind of sensors measure visual information not based on frames from real life and generates corresponding events. In this paper we provide an alternative, based on cheap FPGA, to this image sensors that takes images provided by an analog video source (video composite signal), digitalizes it and generates AER streams for testing purposes.Junta de Andalucía P06-TIC-01417Ministerio de Educación y Ciencia TEC2006-11730-C03-0