On the Role of Relative Prices and Capital Flows in Balance-of-Payments Constrained Growth: the Experiences of Portugal and Spain in the Euro Area

Broadly speaking, the balance-of-payments constraint hypothesis as developed by Thirlwall has been empirically supported. Yet, it shows some shortcomings highlighted in the literature. In our opinion, two of them must be analysed. First, temporary disequilibria and capital flows must be incorporated into the balance-of-payments constrained growth models. Second, the role of relative prices must be made explicit, since it can be relevant even in an external constraint framework. This study is aimed at developing a model that incorporates both possibilities: temporary external disequilibria and a the impact of relative prices. This model is subsequently used to analyse the evolution of the Spanish and Portuguese economies in last decades, and, in particular, the different path shown by both countries since their accession to the Eurozone.Pese al respaldo empírico con el que ha contado la teoría de la restricción externa desarrollada a partir del modelo de Thirlwall, éste muestra algunas deficiencias destacadas en la literatura. En nuestra opinión, dos de ellas merecen ser analizadas. Por un lado, la necesidad de incorporar desequilibrios transitorios de la balanza de pagos y los consiguientes flujos de capital. Por otro, creemos los precios relativos pueden desempeñar un papel importante en el comercio exterior, sin que ello invalide la existencia de una restricción externa. El objetivo del presente trabajo consiste en desarrollar un modelo que incorpore ambas cuestiones, permitiendo, así, un mayor protagonismo a los precios relativos y a los desequilibrios temporales de la balanza de pagos. Este modelo se emplea posteriormente para analizar la evolución de las economías española y portuguesa en las últimas décadas y, en especial, las diferencias mostradas desde su incorporación a la Eurozona.Growth, Balance of payments constraint, Exchange rate.

Guía sobre la utilización de levaduras no Saccharomyces en la elaboración de vinos

Blanco Camba, Pilar et al.-- Trabajo presentado en la XXVIII Reunión Anual del Grupo de Trabajo de Experimentación en Viticultura y Enología, celebrada en Murcia el 16 y 17 de abril de 2013.Peer Reviewe

Efficient Simulation Tools (EST) for sediment transport in geomorphological shallow flows

Entre los fenómenos superficiales geofísicos y medioambientales, los flujos rápidos de mezclas de agua y sedimentos son probablemente los más exigentes y desconocidos de los procesos movidos por gravedad. El transporte de sedimentos es ubicuo en los cuerpos de agua naturales, como ríos, crecidas, costas o estuarios, además de ser el principal proceso en deslizamientos, flujos de detritos y coladas barro. En este tipo de flujos, el material fluidificado en movimiento consiste en una mezcla de agua y múltiples fases sólidas, que pueden ser de distinta naturaleza como diferentes clases de sedimento, materiales orgánicos, solutos químicos o metales pesados en lodos mineros. El modelado del transporte de sedimentos involucra una alta complejidad debido a las propiedades variables de la mezcla agua-sólidos, el acoplamiento de procesos físicos y la presencia de fenómenos multicapa. Los modelos matemáticos bidimensionales promediados en la vertical ('shallow-type') se construyen en el contexto de flujos superficiales y son aplicables a un amplio rango de estos procesos geofísicos que involucran transporte de sedimentos. Su resolución numérica en el marco de los métodos de Volúmenes Finitos (VF) está controlada por el conjunto de ecuaciones escogido, las propiedades dinámicas del sistema, el acoplamiento entre las variables del flujo y la malla computacional seleccionada. Además, la estimación de los términos fuente de masa y momento puede también afectar la robustez y precisión de la solución. La complejidad de la resolución numérica y el coste computacional de simulación crecen considerablemente con el número de ecuaciones involucradas. Además, la mayor parte de estos flujos son altamente transitorios y ocurren en terrenos irregulares con altas pendientes, requiriendo el uso de una discretización espacial no-estructurada refinada para capturar la complejidad del terreno e incrementando exponencialmente el tiempo computacional. Por tanto, el esfuerzo computacional es uno de los grandes retos para la aplicación de modelos promediados 2D en flujos realistas con grandes escalas espaciales y largas duraciones de evento. En esta tesis, modelos matemáticos superficiales 2D apropiados, algoritmos numéricos de VF robustos y precisos, y códigos eficientes de computación de alto rendimiento son combinados para desarrollar Herramientas Eficientes de Simulación (HES) para procesos medioambientales superficiales involucrando transporte de sedimentos con escalas temporales y espaciales realistas. Nuevas HES capaces de trabajar en mallas estructuradas y no-estructuradas son propuestas para el flujos de lodo/detritos con densidad variable, transporte pasivo en suspensión y transporte de fondo generalizado. Una atención especial es puesta en el acoplamiento entre las variables del sistema y en la integración de los términos fuente de masa y momento. Las propiedades de cada HES han sido cuidadosamente analizadas y sus capacidades demostradas usando tests de validación analíticos y experimentales, así como mediciones en eventos reales.Among the geophysical and environmental surface phenomena, rapid flows of water and sediment mixtures are probably the most challenging and unknown gravity-driven processes. Sediment transport is ubiquitous in environmental water bodies such as rivers, floods, coasts and estuaries, but also is the main process in wet landslides, debris flows and muddy slurries. In this kind of flows, the fluidized material in motion consists of a mixture of water and multiple solid phases which might be of different nature, such as different sediment size-classes, organic materials, chemical solutes or heavy metals in mine tailings. Modeling sediment transport involves an increasing complexity due to the variable bulk properties in the sediment-water mixture, the coupling of physical processes and the presence of multiple layers phenomena. Two-dimensional shallow-type mathematical models are built in the context of free surface flows and are applicable to a large number of these geophysical surface processes involving sediment transport. Their numerical solution in the Finite Volume (FV) framework is governed by the particular set of equations chosen, by the dynamical properties of the system, by the coupling between flow variables and by the computational grid choice. Moreover, the estimation of the mass and momentum source terms can also affect the robustness and accuracy of the solution. The complexity of the numerical resolution and the computational cost of simulation tools increase considerably with the number of equations involved. Furthermore, most of these highly unsteady flows usually occur along very steep and irregular terrains which require to use a refined non-structured spatial discretization in order to capture the terrain complexity, increasing exponentially the computational times. So that, the computational effort required is one of the biggest challenges for the application of depth-averaged 2D models to realistic large-scale long-term flows. Throughout this thesis, proper 2D shallow-type mathematical models, robust and accurate FV numerical algorithms and efficient high-performance computational codes are combined to develop Efficient Simulation Tools (EST's) for environmental surface processes involving sediment transport with realistic temporal and spatial scales. New EST's able to deal with structured and unstructured meshes are proposed for variable-density mud/debris flows, passive suspended transport and generalized bedload transport. Special attention is paid to the coupling between system variables and to the integration of mass and momentum source terms. The features of each EST have been carefully analyzed and their capabilities have been demonstrated using analytical and experimental benchmark tests, as well as observations in real events.<br /

On the Role of Relative Prices and Capital Flows in Balance-of-Payments Constrained Growth: the Experiences of Portugal and Spain in the Euro Area

Broadly speaking, the balance-of-payments constraint hypothesis as developed by Thirlwall has been empirically supported. Yet, it shows some shortcomings highlighted in the literature. In our opinion, two of them must be analysed. First, temporary disequilibria and capital flows must be incorporated into the balance-of-payments constrained growth models. Second, the role of relative prices must be made explicit, since it can be relevant even in an external constraint framework. This study is aimed at developing a model that incorporates both possibilities: temporary external disequilibria and a the impact of relative prices. This model is subsequently used to analyse the evolution of the Spanish and Portuguese economies in last decades, and, in particular, the different path shown by both countries since their accession to the Eurozone

¿Una Geografía del Medio Ambiente?

En reseña de:Claude y Georges Bertrand: Geografía del Medio Ambiente. El sistema GTP: Geosistema, Territorio y Paisaje. universidad  de granada, 2006

Le panier de biens et services en tant qu’outil de diagnostic territorial: Le cas de la wilaya d’Ain-Témouchent (Algerie)

La provincia de Jaén es el ejemplo más radical de especialización olivarera del mundo, destinando a este cultivo más del 91% de su superficie agrícola. A través de fuentes cartográficas se reconstruye la expansión acaecida desde mediados del siglo XX, reparando en las claves espaciales de un proceso en el que ha predominado la estrategia de sustitución de otros usos agrícolas antes que la expansión de la frontera agrícola. Igualmente se identifican algunas de las características actuales de este monocultivo extremo, entre ellas las que permiten entender su elevada productividad global (incremento de la superficie regada, ocupación de suelos de mejores condiciones agronómicas) o la convivencia de olivares de muy diferente paisajística y potencialidad económica.The province of Jaen is the most radical example of olive specialization of the world, destining to the olive groves more than 91 % of its agricultural surface. Through cartographic sources of expansion took place from middle of the 20th century is reconstructed, stressing in the spatial keys of a process in which there has predominated the strategy of substitution of other agricultural uses before that the expansion of the agricultural frontier. Likewise, there are identified some of the current characteristics of this extreme monoculture, between them those who allow us to understand its high global productivity (increase of the irrigated surface, take up of soils of better agronomic conditions) or the coexistence of olive groves of very different landscape and economic potential.La province de Jaén est exemplaire dans le monde entier pour son oléiculture, car plus de 91 % de ses terres agricoles sont consacrées à l’olivier. Les sources cartographiques permettent de reconstruire l’extension qui a lieu depuis la seconde moitié du XXe siècle, selon laquelle on remarque un processus qui a privilégié de remplacement d’autres cultures plutôt que l'expansion de la frontière agricole. On y identifie également quelques-unes des fonctionnalités actuelles de cette monoculture extrême, dont celles qui permettent de comprendre sa productivité globale élevée (augmentation de la superficie irriguée, occupation des sols de meilleures conditions agronomiques) ou la coexistence des oliveraies très différentes selon le paysage et le rendement économique

Non-constant Discounting, Social Welfare and Endogenous Growth with Pollution Externalities

Producción CientíficaWe analyze the effect of non-constant discounting on economic growth and social welfare in an endogenous growth model with pollution externalities. For time-consistent agents, who play a game against their future selves, the balanced growth equilibrium is compared to the case of standard exponential discounting. A decaying instantaneous discount rate leads to slower growth in a centralized economy, while its effect for a competitive economy is ambiguous. Interestingly, when comparing the planned and the competitive equilibria, the assumption of non-constant discounting may imply greater social welfare in the market equilibrium under two conditions. First, the pollution externality on utility must be large with respect to the externality on production, so that the central planner slows down growth below the growth rate in the market economy. Secondly, individuals’ degree of impatience should decrease sharply with the time distance from the present. Concerning policy implications, we observe that under log-utility policies may not be necessary, while for an isoelastic utility with an elasticity lower than one, introducing policy instruments is less effective than under constant discounting.Ministerio de Economía y Competitividad ECO2014-52343-P y Fondos FEDERMinisterio de Economía y Competitividad ECO2017- 82227-P y Fondos FEDERConsejería de Educación, Junta de Castilla y León VA024P17 y fondos FEDERConsejería de Educación, Junta de Castilla y León VA105G18 y fondos FEDE

A Note on the Stability of Fully-Endogenous Growth with Increasing Returns and Exhaustible Resources

Producción CientíficaWe introduce an exhaustible natural resource as an essential input in a general R&D-based endogenous growth model, which makes increasing returns to scale to man-made inputs com- patible with non-explosive sustained growth. The instability problem usually associated with increasing returns is overcome thanks to the existence of imperfect markets in a decentralized economy. The economy comprises two separate sectors: nal output and R&D, both directly or indirectly dependent on the natural resource. Without the requirement of any knife-edge assumption, we prove that growth is fully endogenous and saddle-path stable.The authors have been partially supported by MEC under projects ECO2008-01551, ECO2011-24352 (co-financed by FEDER funds) and the COST Action IS1104 “The EU in the new economic complex geography: models, tools and policy evaluation”

Present bias and the inefficiency of the centralized economy. The role of the elasticity of intertemporal substitution

Producción CientíficaWe analyze an endogenous growth model considering agents with an isoelastic utility. Preferences are characterized by a utility affected by a negative externality, and a level of impatience which decays with the time distance from the present. Agents who cannot commit the actions of their future selves, play a game against them. The stationary equilibrium of this game defines a balanced growth path with a slower growth when played by subsequent central planners than when played by decision makers in the market economy. First, we prove that the fast growing market economy implies higher welfare if the negative externality is small, while the centralized economy is welfare improving above a given threshold for the externality (obtained for a specific family of non-constant discount functions). Secondly, we observe that this threshold increases with the elasticity of intertemporal substitution in consumption. Therefore, the greater this elasticity the more likely it is that the externality lies below this threshold, where policy interventions would not be adequate. Finally, as one would expect, the range of values of the externality for which the market equilibrium provides higher welfare widens the more different from constant discounting time preferences are, due either to a wider range of variation for the instantaneous discount rates or because these decay more slowly.Ministerio de Economía y Competitividad ECO2014-52343-P y Fondos FEDERMinisterio de Economía y Competitividad ECO2017- 82227-P y Fondos FEDERConsejería de Educación, Junta de Castilla y León VA024P17 y fondos FEDERConsejería de Educación, Junta de Castilla y León VA105G18 y fondos FEDE