Fortification and Frontier: The Project Drawn up by Juan Martín Zermeño for Puebla de Sanabria in 1766

Following the death of engineer General Jorge Próspero de Verboom in 1744 and after a few years of transition in the management of Spanish fortifications, Juan Martín Zermeño took on the role, initially with a temporary mandate, but then definitively during a second period that ran from 1766 until his death in 1772. He began this second period with a certain amount of concern because of what had taken place during the last period of conflict. The Seven Years War (1756–1763) which had brought Spain into conflict with Portugal and England in the Caribbean had also lead to conflict episodes along the Spanish–Portuguese border. Zermeño’s efforts as a planner and general engineer gave priority to the northern part of the Spanish–Portuguese border. After studying the territory and the existing fortifications on both sides of the border, Zermeño drew up three important projects in 1766. The outposts that needed to be reinforced were located, from north to south, at Puebla de Sanabria, Zamora and Ciudad Rodrigo, which is where he is believed to have come from. This latter township already had a modern installation built immediately after the war of the Spanish Succession and reinforced with the Fort of La Concepción. However, Zamora and Puebla de Sanabria had some obsolete fortifications that needed modernising. Since the middle of the 15th century Puebla de Sanabria had had a modern castle with rounded turrets, that of the counts of benavente. During the 16th and 17th centuries it had also been equipped with a walled enclosure with small bastions. During the war of the Spanish Succession the Portuguese had enlarged the enclosure and had erected a tentative offshoot to the west. In order to draw up the ambitious Puebla de Sanabria project Zermeño had the aid of some previous reports and projects, such as those by the count of robelin in 1722, the one by Antonio de Gaver in 1752, and Pedro Moreau’s report dated June 1755. This study includes a technical analysis of Zermeño’s project and its strategic position within the system of fortifications along the Spanish–Portuguese border.

Eficiencia en la distribución: una aplicación en el sector de agencias de viajes

El objetivo de este trabajo consiste en estimar la eficiencia productiva y de escala con la que operan los intermediarios del sector minorista español de distribución turístico. Adicionalmente, se pretende examinar los determinantes de la eficiencia en términos de la integración vertical, concentración horizontal, tamaño y resultados de las entidades. La metodología aplicada se apoya en diversas técnicas de medición de eficiencia (paramétrica de naturaleza estocástica y no paramétrica del Análisis Envolvente de Datos, DEA), así como en modelos tobit para conocer el impacto de los factores del mercado y de la empresa sobre los niveles de eficiencia. La aplicación empírica realizada en una muestra de 50 agencias de viaje de nuestro país evidencia, por un lado, unos elevados índices de ineficiencia técnica y de escala, destacando en el último caso los rendimientos decrecientes; y por otro, que el tamaño y el ROA son los factores determinante de la eficiencia de escala, mientras que la concentración del mercado explica la eficiencia técnica.

Determinantes de la eficiencia en el canal de distribución: análisis en agencias de viajes

El incremento de la competencia entre agencias de viajes y el impacto del comercio electrónico como una alternativa al canal de distribución turístico tradicional han dado lugar a un entorno en el que la gestión eficiente de los recursos productivos resulta fundamental para las agencias de viajes. Así, el objetivo del trabajo consiste en estimar la eficiencia con la que operan los intermediarios del sector minorista español de distribución turístico, y conocer la influencia de algunos de sus factores determinantes (salarios, antigüedad y oferta de servicios de comercio electrónico). La metodología de investigación se apoya en la estimación de una frontera paramétrica de naturaleza estocástica. El análisis empírico efectuado sobre una muestra de 1086 agencias de viajes en 2004 evidencia bajos niveles de eficiencia, que son explicados por el nivel de salarios medio y por la antigüedad de la agencia.

El sur también existe: las relaciones migratorias entre las islas Baleares y la Argelia francesa (1830-1962)

La Argelia francesa (1830-1962) constituyó un poderoso polo de atracción para los habitantes de las islas Baleares y del sudeste peninsular. En este artículo se analizan las relaciones migratorias y comerciales entre el archipiélago balear y su por entonces próspero vecino del sur. Además, también se estudian los diferentes exilios que vincularon las dos riberas del Mediterráneo. Para realizar este artículo se han combinado tanto fuentes primarias como la bibliografía existente.

A new boundary-based morphological model

Mathematical morphology addresses the problem of describing shapes in an n-dimensional space using the concepts of set theory. A series of standardized morphological operations are defined, and they are applied to the shapes to transform them using another shape called the structuring element. In an industrial environment, the process of manufacturing a piece is based on the manipulation of a primitive object via contact with a tool that transforms the object progressively to obtain the desired design. The analogy with the morphological operation of erosion is obvious. Nevertheless, few references about the relation between the morphological operations and the process of design and manufacturing can be found. The non-deterministic nature of classic mathematical morphology makes it very difficult to adapt their basic operations to the dynamics of concepts such as the ordered trajectory. A new geometric model is presented, inspired by the classic morphological paradigm, which can define objects and apply morphological operations that transform these objects. The model specializes in classic morphological operations, providing them with the determinism inherent in dynamic processes that require an order of application, as is the case for designing and manufacturing objects in professional computer-aided design and manufacturing (CAD/CAM) environments. The operators are boundary-based so that only the points in the frontier are handled. As a consequence, the process is more efficient and more suitable for use in CAD/CAM systems.