Libro de Apolonio.

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Graphs associated with nilpotent Lie algebras of maximal rank

In this paper, we use the graphs as a tool to study nilpotent Lie algebras. It implies to set up a link between graph theory and Lie theory. To do this, it is already known that every nilpotent Lie algebra of maximal rank is associated with a generalized Cartan matrix A and it is isomorphic to a quotient of the positive part n+ of the KacMoody algebra g(A). Then, if A is affine, we can associate n+ with a directed graph (from now on, we use the term digraph) and we can also associate a subgraph of this digraph with every isomorphism class of nilpotent Lie algebras of maximal rank and of type A. Finally, we show an algorithm which obtains these subgraphs and also groups them in isomorphism classes

Power distribution supervisory control system by polling

This paper describes a new Supervisory Control System (SCS) which adopts a dynamic polling structure. The need for a thinking unit at the line head for manaing a SCS is unavoidable. The thinking unit (mP) moreover, allows a communication network to be built up which uses the line without voltage, with a variable number of transmitter-receiver stations attached to the equipped centres. Configuration of the Distribution Network is discussed, the aims that the SCS must fulfil, the system functions and a digital data transmission system description.Peer ReviewedPostprint (published version

A Real time simulation model for Lognormal Fading channels

In this paper we present a mathematical model for the simulation of lognormal fading channels. A modeling technique and its validation by computer simulation are described with special emphasis on the aspects related to the spectrum shaping. The obtained results have shown that it is possible to control the fading depth and the fading rate with a good enough reliability in their usual variation ranges.Peer ReviewedPostprint (published version

Regeneration of potential laurel forest under a native canopy and an exotic canopy, Tenerife (Canary Islands)

Exotic tree monocultures adversely affect native ecosystems through competition and through alteration of nutrient availability and dynamics. However, evidence suggests that some tree plantations facilitate a more rapid recovery of native plant communities by providing shelter to the plants below and by attracting seed dispersers. The results are specific to the plantation species and the type of native forest. In this study, we analyzed the differences in regeneration of native woody species in two stands of exotic species, Pinus radiata and Eucalyptus globulus, occupying native laurel forest ground. We also examined the process of regeneration in two adjacent native forest stands to determine whether the exotic plants negatively affect the recovery of the native plant community. The native stands differed from the exotic stands in tree species richness and basal area. However, regeneration was similar in alien and native stands. Differences were quantitatively important, but the species composition of the regenerating community was similar. Moreover, these planted areas recovered their canopy quickly because P. radiata and E. globulus have rapid growth in comparison with native laurel forest species. The rapid recovery of the canopy has prevented more serious erosion damage and has to some extent facilitated the regeneration of native species. The results of this study indicate that a progressive elimination of the exotic stands would favor the establishment and growth of native species. The role of some exotic tree species in the restoration of laurel forest areas should not always be seen as negative

Consecuencias de la fragmentación viaria: efectos de borde de las carreteras en la laurisilva y el pinar de Tenerife

La infraestructura viaria es uno de las principales causas de fragmentación ecológica en todo el mundo. Además de la división y reducción del área del ecosistema, las carreteras causan un aumento en la permeabilidad a los impactos externos al incrementar las áreas marginales o de borde. Los efectos de borde viarios son un aspecto de la fragmentación raramente evaluado en islas oceánicas, distinguidas por su especial fragilidad a las perturbaciones antrópicas. En este capítulo se exploran algunos cambios inducidos por los márgenes de carreteras y pistas de los bosques canarios (laurisilva y pinar). La red viaria causa importantes cambios en el gradiente borde-interior, que se perciben en el microclima, estructura y composición de la vegetación, abundancia y diversidad de la comunidad de invertebrados del mantillo, respuestas comunitarias y específicas de las aves, y la actividad depredadora de vertebrados invasores como las ratas. Se discuten las implicaciones de los efectos hallados para estos bosques insulares subtropicales.The road infrastructure is a major cause of ecological fragmentation worldwide. Apart from ecosystem division and area reduction, roads increase habitat permeability to outer influences due to the augmentation of edge areas. Road edge effects are a fragmentation process rarely evaluated on oceanic islands, which are especially fragile against human activities. Here we explore some changes produced by paved roads and trails on the Canarian forest ecosystems (laurel and pine forest). The road net generates important changes along the road edge-forest interior gradient. These alterations are perceived in microclimate, vegetation structure and composition, abundance and diversity of the litter invertebrate community, bird community and specific responses, and predator activity of vertebrate invaders such as rats. Implications of these findings are discussed for these subtropical insular forests

Estrategias de regeneración en la laurisilva

Estrategias de regeneración del bioma forestal de laurisilva en Canarias analizando los precedentes en otros territorios

Haciendo visibles procesos e interacciones ecológicas a través de la experimentación

El presente proyecto aborda la facilitación del aprendizaje de conceptos abstractos en ecología mediante experimentación.Para ello proponemos la realización de modelos de experimentación que permitan abordar conceptos abstractos en ecología a través de la selección de procedimientos experimentales necesarios para obtener las mediciones (el cómo se hace). Sobre estos procedimientos se realizará un modelo lo más real posible con todos los elementos básicos, de manera que los estudiantes puedan ver la configuración material del mismo y, sobre éste esquema discutir las limitaciones empíricas y su aportación a la generalización abstracta del proceso medido. El resultado son tres productos prácticos que incluyen el desarrollo teórico, un guión de prácticas, hojas de cálculo (Excel) para la realización de los cálculos y una presentación que permite conocer detalles teóricos y del desarrollo material de la práctica