Synthesis of an acidic biomorphic carbon-based catalyst for simultaneous esterification and transesterification reactions

The activation of cellulose followed by sulfonation produces a biomorphic functionalized carbon material with acid catalytic activity as a solid-acid replacement for homogeneous catalysts. The carbon-based material contains carboxylic and sulfonic acid groups and exhibits high catalytic performance for liquid-phase acid-catalyzed reactions in presence of water. The activation of cellulose at high temperature (600ºC) followed by sulfonation also results in an amorphous carbon with an acidity value close to 1.52 mmol.g-1. The catalytic test shows that the sulfated carbon has enough amount of sulfonic acid groups and exhibit high catalytic activity and stability for esterification and tranesterification of raw materials; achieving a comversion value close to 90.5% at 2h of reaction comparable to an homogeneous catalysts. Structural and active site analyses suggest that the marked difference in catalytic activity is due to the accessibility of reactants to sulfonic acid groups in the carbon structure.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Evolutionary ecology of host-symbiont interactions

Imperial Users onl

Productive Capital and Technical Efficiency in the UE-15

In this research we examine the capitalization process in the UE-15 with the aim to establish if the evolution manteined in the last two decades for the public capital and its distribution related private capital have conditioned the technical efficiency of the European economies. In this analysis we use the frontier function approach that allows to consider an inefficiency use of the productive factors. Specifically, we employ the parametric stochastic frontier model from Battese and Coelli (1995) to explore the determinants of the technical efficiency. The results show that larger endowments of public capital may facilitate the access of the productive activity to the levels of the more efficient members. We also find a limit to the capacity of introducing improvements in the use of productive factors, and it is related to private capital, then if the increase of public capital does not lead to an optimal distribution of this factor, the effect on efficiency will be negative.

Long Term Evolution of the Size Distribution of Portuguese Cities

In this paper we study the evolution of the Portuguese urban system from 1864 to 2001. We apply the rank-size model and use rank-size estimates to describe the evolution of city-size hierarchy. Non paretian behaviour of the distribution is examined by adding a quadratic term to the basic equation of the model. Our results enhance two different processes in the evolution of urban system: until the middle of the twentieth century urban growth was accompanied by population concentration in the largest cities and proliferation of small cities; afterwards growth benefits middle size cities, reinforced in the last decades by heavy population losses in the two largest cities. From the association between the characteristics and evolving pattern of city size distribution and the spatial pattern of urban growth, it appears that the non paretian behaviour of city size distribution in the last decades can be linked to the particular growth process of cities located in the proximity of the central cities of the two metropolitan areas of Portugal’s mainland. In order to obtain a better understanding of the dynamics of the Portuguese urban system we examine the movements in the ranking of cities. We also analyse the existence of spatial correlation in the process of urban hierarchy restructuring.

Understanding the Institutional Evolution of the European Rural Policy: A Methodological Approach

Last decades have seen the development of a new rural policy. Different problems occurring in rural areas have pushed the EU Commission to draft policy instruments aiming to address them. However this rural policy path has not always been explicit neither has followed a continuous trend but rather has seen a series of forward and backward steps. Given the lack of a method to establish the relevance and the level of political acceptance of EU rural policy, a methodology has been developed. This methodology has tried to identify the EU political procedure trend, though this is not a formal sequence, and to establish a classification of different events according to a proposed hierarchy. Several EU documents, decisions, directives and financial resource allocations have been analysed. Within the review performed, each rural policy milestone has been classified following the proposed hierarchical chart. This has enabled the drawing of the different backs and forwards taken by this process. Besides, it has lead to the interpretation of the rural policy instruments current position in relation with other European policy instruments.Rural development, policy analysis, institutional processes, Agricultural and Food Policy,

The evolution of city size distribution in Portugal: 1864-2001

The rank-size model - which states that the size distribution of cities in a country follows a Pareto distribution - has been recognized as one of those stylized facts or amazing empirical regularities, in spatial economics. A common problem in city size distribution studies concerns the definition of “cities”, namely the consistency of those definitions over time. In this paper we use a city-proper data base which uses a consistent definition of cities from 1864 to 1991. Portugal is a country with long established national borders and whose mainland urban system shows a constant number of cities over that period. In Portugal, empirical evidence on city size distribution based on census data shows that two large cities dominate the urban system, associated with a large number of very small cities and a clear deficit of medium-size cities. In this paper we analyse the evolution of the rank size exponent and examine the effect of varying city size cut-offs on the estimate value of that exponent. Then, we study the deviations of the rank-size distribution from linearity. Finally, we explore the dynamics underlying the evolution of the urban system by examining the relationship between city growth rates and city size.city size distribution, Zipf’s law, urban hierarchy, urban primacy

The evolution of city size distribution in Portugal: 1864-2001

The rank-size model - which states that the size distribution of cities in a country follows a Pareto distribution - has been recognized as one of those stylised facts or amazing empirical regularities, in spatial economics. A common problem in city size distribution studies concerns the definition of “cities”, namely the consistency of those definitions over time. In this paper we use a city-proper data base which uses a consistent definition of cities from 1864 to 1991. Portugal is a country with long established national borders and whose mainland urban system shows a constant number of cities over that period. In Portugal, empirical evidence on city size distribution based on census data shows that two large cities dominate the urban system, associated with a large number of very small cities and a clear deficit of medium-size cities. In this paper we analyse the evolution of the rank size exponent and examine the effect of varying city size cut-offs on the estimated value of that exponent. Then, we study the deviations of the rank-size distribution from linearity. Finally, we explore the dynamics underlying the evolution of the urban system by examining the relationship between city growth rates and city size. Keywords: city size distribution, Zipf’s law, rank-size, urban hierarchy, urban primacy

Long term evolution of the size distribution of Portuguese cities

In this paper we study the evolution of the Portuguese urban system from 1864 to 2001. We apply the rank-size model and use rank-size estimates to describe the evolution of city-size hierarchy. NonParetian behavior of the distribution is examined by adding a quadratic term to the basic equation of the model. Our results enhance two different processes in the evolution of urban system: until the middle of the twentieth century urban growth was accompanied by population concentration in the largest cities; afterwards growth benefits middle size cities, reinforced in the last decades by heavy population losses in the two largest cities. From the association between the characteristics and evolving pattern of city size distribution and the spatial pattern of urban growth, it appears that the nonParetian behavior of city size distribution in the last decades can be linked to the particular growth process of cities located in the proximity of the central cities of the two metropolitan areas of mainland Portugal. In order to obtain a better understanding of the dynamics of the Portuguese urban system we examine the movements in the ranking of cities, through a Markov chain process. We also analyse the existence of spatial correlation in the process of urban hierarchy restructuring.Urban hierarchy, rank-size distribution, urban growth, Markov processes

Trabajo colaborativo interdepartamental a través de las tecnologías de la información y comunicación. Nexo bidireccional para las didácticas en educación

El presente resumen pretende abordar el nexo tan íntimo existente entre la metodología del trabajo colaborativo interdepartamental y las tecnologías de la información y comunicación. Ambos ámbitos metodológicos forman un tándem que se retroalimentan bidireccionalmente. Estos dos ámbitos, pese a pertenecer a ramas de diferente árbol, comparten multitud de similitudes, tales como: o Estimulan la creatividad, ya que al mismo tiempo se pueden compartir ideas interesantes surgidas teniendo infinidad de herramientas al alcance de todos los miembros. o La comunicación interdepartamental a través de las Tic crea una relación de igualdad entre los componentes de un grupo con un proyecto común. o Este binomio fomenta, a su vez, la multiculturalidad fruto de la elaboración de un proyecto común entre compañeros distantes en espacio, físicamente hablando. Así pues, la barrera de la distancia, gracias a los avances tecnológicos y al buen uso de ellos, se ha desvanecido. o Facilitar y potenciar la comunicación. En mi experiencia de casi tres décadas como docente, he podido observar, tanto en enseñanzas secundarias, bachillerato, así como, en el ámbito universitario, la verdadera satisfacción experimentada por los alumnos desde el momento que se les plantea un nuevo proyecto audiovisual, así como durante el desarrollo del mismo. En los planes de estudio de este país remodelados en la última década se contempla este aspecto, por ello las asignaturas de nuestro campo han pasado a llamarse Educación Plástica y Audiovisual. Las tecnologías van evolucionando de forma vertiginosa, en ocasiones, difícil de seguir. Pero este lenguaje común entre docentes y discentes, y entre ambos con los iguales, es similar al garabato de un niño en la etapa de autoexpresión; un canal de comunicación y de información de infinitas posibilidades. Por consiguiente, tenemos al alcance de nuestras manos el empleo de un lenguaje unificador, de acercamiento y potenciador de la motivación.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec