Caminos Pareto-eficientes en redes: aplicaciones

The problem of finding the path in a network connecting two given nodes, source and sink, with minimum possible cost is known in the literature as the shortest path problem (SPP) and it is a core model that lies at the heart of network optimization. The reason is the wide range of its practical applications and the large amount of interesting generalizations that can be considered, among them, the analysis of the multiobjective shortest path problem. This last model allows us to find how to send a given product between two specified nodes of a network as quickly, as cheaply and as reliable as possible taking into account the so-called Pareto optimal paths. The text presented here consists of two chapters. The first one is devoted to the introduction of some notation and properties related to networks where each arc is associated to just one cost value. The formulation of the SPP as a Mathematical Programming model is considered as well as its corresponding dual problem. The complementary slackness theorem provides us with a characterization of any basic feasible solution as a spanning tree in the original network. A sufficient optimality condition is also derived from this relation. Finally, the Dijkstra algorithm is studied as well as other specific algorithms that use special properties on acyclic networks. The second chapter extends the hypotheses considered in the previous one to a multiobjective context. The continuous formulation of the problem of finding the Pareto optimal paths is compared with its discrete version and some properties are stated. A generalization of the Dijkstra algorithm is proposed in order to find the whole set of Pareto optimal solutions. This procedure allows us to determine that the optimal set of paths corresponds with a set of adjacent trees. This property is very important in order to generate the Pareto optimal set of solutions and is the basis of a new improved algorithm that, starting with a given optimal tree, explores its adjacent trees and finds those Pareto optimal ones by using the duality conditions of the complementary slackness theorem presented in the chapter one.Universidad de Sevilla. Grado en Matemática

The criteria of classification of inert matter in Primay Education: conceptions of students and competency levels

En este artículo se describen y analizan los criterios que los alumnos de Primaria utilizan para clasificar la materia inerte y cómo emplean los criterios básicos de clasificación (sustancia pura/mezcla). El estudio1 se ha realizado con 55 alumnos de 2º, 4º y 6º de Primaria del Colegio Público Trabenco de Leganés (Madrid), a partir de los datos suministrados por una tarea de clasificación de imágenes elaborada a tal efecto. Los resultados sugieren que los alumnos utilizan una diversidad de criterios basados en la percepción y en la utilidad, así como los criterios natural/artificial y uno/varios componentes para aplicar los criterios básicos de clasificación de la materia inerte. Por último, como principal implicación didáctica se proponen diferentes niveles de competencia en la clasificación de la materia en la Educación Primaria.This article describes and analyzes the criteria elementary students used to classify inert matter and how they use the basic criteria of classification (pure substance/mixture). The study was conducted with 55 students of 2º, 4º and 6º of Primary Public School Trabenco Leganés (Madrid), from data supplied by an image classification task developed for this purpose. The results suggest that students use a variety of criteria based on the perception an use, and the criteria for natural/artificial and one /multiple components to apply the basic criteria classification of inert matter.Finally, as the main educational implication proposed different levels of competency in the classification of matter at Primary Education

Los criterios básicos de clasificación de la materia: concepciones y niveles de competencia en alumnos y futuros maestros de Primaria

This article will describe, analyze and compare the criteria that a sample of 55 students from the three primary cycles and 55 prospective teachers used to classify the material and how they use the basic criteria of classification (alive / not live) from data supplied by an image classification task developed for this purpose. The results indicate that all use a variety of criteria, emphasizing the food and spontaneous approach and partnership in primary live-motion, while the character alive / not alive and vital functions are major criteria among future teachers, but without applying a concept of life scientifically acceptable and consistent with the content of formal education. Finally, we propose different levels of competency in the classification of the subject and identifies implications for teaching and teacher education.En este artículo se describen, analizan y comparan los criterios que, una muestra de 55 alumnos de los tres ciclos de Primaria y 55 estudiantes del Grado de Maestro, utilizan para clasificar la materia y cómo emplean los criterios básicos de clasificación (vivo / no vivo) a partir de los datos suministrados por una tarea de clasificación de imágenes elaborada a tal efecto. Los resultados indican que todos utilizan una gran diversidad de criterios, destacando la comida como criterio espontáneo y la asociación vivo-movimiento en Primaria, mientras que el carácter vivo/no vivo y las funciones vitales son criterios mayoritarios entre los futuros maestros, pero sin aplicar un concepto de vida científicamente aceptable. Por último, se proponen diferentes niveles de competencia en la clasificación de la materia y se señalan implicaciones para la enseñanza y la formación inicial de maestros

Gene clusters for β-lactam antibiotics and control of their expression: why have clusters evolved, and from where did they originate?

While β-lactam compounds were discovered in filamentous fungi, actinomycetes and gram-negative bacteria are also known to produce different types of β-lactams. All β-lactam compounds contain a four-membered β-lactam ring. The structure of their second ring allows these compounds to be classified into penicillins, cephalosporins, clavams, carbapenens or monobactams. Most β-lactams inhibits bacterial cell wall biosynthesis but others behave as β-lactamase inhibitors (e.g., clavulanic acid) and even as antifungal agents (e.g., some clavams). Due to the nature of the second ring in β-lactam molecules, the precursors and biosynthetic pathways of clavams, carbapenems and monobactams differ from those of penicillins and cephalosporins. These last two groups, including cephamycins and cephabacins, are formed from three precursor amino acids that are linked into the α-aminoadipyl-L-cysteinyl-D-valine tripeptide. The first two steps of their biosynthetic pathways are common. The intermediates of these pathways, the characteristics of the enzymes involved, the lack of introns in the genes and bioinformatic analysis suggest that all of them should have evolved from an ancestral gene cluster of bacterial origin, which was surely transferred horizontally in the soil from producer to non-producer microorganisms. The receptor strains acquired fragments of the original bacterial cluster and occasionally inserted new genes into the clusters, which once modified, acquired new functions and gave rise to the final compounds that we know. When the order of genes in the Streptomyces genome is analyzed, the antibiotic gene clusters are highlighted as gene islands in the genome. Nonetheless, the assemblage of the ancestral β-lactam gene cluster remains a matter of speculation. [Int Microbiol 2006; 9(1):9-19

Scientific, Technical and Economic Committee for Fisheries (STECF) - Request for an evaluation of the fulfillment of the condition for exclusion under Art 11 of the cod plan (STECF-13-16)

Casey, John ... et. al.-- This report was reviewed by the STECF by written procedure in August 2013.-- 9 pagesThe STECF commented on a request for an evaluation of the fulfilment of the condition for exclusion under Art 11 of the cod plan by written procedure in August 2013Peer Reviewe

Criterios de eficiencia y buenas prácticas en los procesos de concentración de las organizaciones de participación

En el estudio de la Responsabilidad Social Empresarial en las sociedades cooperativas hay que identificar sus ámbitos de aplicación, así como los grupos de interés, su particular relación con la empresa y el tratamiento de la eficiencia como principio empresarial y como combinación de esfuerzos hacia la Responsabilidad Social.De esta forma a lo largo del presente trabajo se plantea el estudio de la Responsabilidad Social Empresarial para el caso de las sociedades cooperativas, por una parte desde la esfera interna o núcleo que de la propia definición de Responsabilidad Social atendería a los trabajadores, los clientes y los proveedores, esto es a los socios; y por otra, desde una esfera más amplia que atendería a los competidores, la comunidad local, el medio ambiente y la sociedad en general. Para ello, se analizan como requerimientos fundamentales en el ámbito interno, la eficiencia en la participación de los socios en los flujos empresariales, y en el ámbito externo, la concentración empresarial de las sociedades cooperativas, así como las variables que se ven modificadas en los procesos de concentración empresarial en aras de conseguir valores que ensalcen el buen gobierno y la Responsabilidad Social Empresarial. Por último, se tratar de determinar los efectos que los procesos de concentración tienen en la determinación del valor de la Responsabilidad Social en las sociedades cooperativas.In the study of Corporate Social Responsibility in cooperative societies it is necessary to identify its areas of application, as well as the groups of interest, its particular relation with the company and the treatment of the efficiency as managerial principle and as combination of efforts towards the Social Responsibility. This work sets out to study Corporate Social Responsibility for the case of cooperative societies, on one hand from the internal sphere or core that of the definition of Corporate Social Responsibility would pay attention to the workers, the customers and the suppliers, this is to the associates, and on the other hand from a wider sphere that would take in account the competitors, the local community, the environment and the society in general. For it, it is analyzed as fundamental requirements in the internal area, the efficiency in the participation of the associates in the managerial flows, and in the external area, the managerial concentration of the cooperative societies, as well as the variables that are modified in the processes of managerial concentration to obtain values that increase the good government and the Corporate Social Responsibility. Finally, it is determined the effects that the processes of concentration have in the determination of the value of the Social Responsibility in the cooperative societies.Dans l'étude de la Responsabilité Sociale Patronale dans les sociétés coopératives il faut identifier ses enceintes d'application, ainsi que les groupes d'intérêt, sa relation particulière avec l'entreprise et le traitement de l'efficacité comme un principe patronal et comme combinaison d'efforts vers la Responsabilité Sociale. De cette façon le long du travail présent il se pose l'étude de la Responsabilité Sociale Patronale pour le cas des sociétés coopératives, d'une part depuis la sphère interne ou le noyau qui de la propre définition de Responsabilité Sociale Corporative s'occuperait des travailleurs, des clients et des fournisseurs, c'est aux associés; et par l'autre, depuis une sphère plus vaste dont il s'occuperait aux concurrents, la communauté locale, l'environnement et à la société en général. Pour cela, ils sont analysés comme requêtes fondamentales dans l'enceinte interne, l'efficacité dans la participation des associés dans les flux patronaux, et dans l'enceinte externe, la concentration patronale des sociétés coopératives, ainsi que les variables qui se trouvent modifiées dans les processus de concentration patronale en l'honneur de cela obtenir des valeurs ce qu'ensalcen le bon gouvernement et la Responsabilité Sociale Patronale. Enfin, se fréquenter de déterminer les effets que les processus de concentration ont dans la détermination de la valeur de la Responsabilité Sociale dans les sociétés coopératives

Reports of the Scientific, Technical and Economic Committee for Fisheries (STECF) - The application of the landing obligation on the fisheries targeting Venus clams in the Northern Adriatic Sea (STECF-16-06)

Ulrich, C. ... et al.-- This report was iisued during the plenary meeting held in Brussels, 10-15 April 2016.-- 26 pages, 1 figure, 2 annexesCommission Decision of 25 February 2016 setting up a Scientific, Technical and Economic Committee for Fisheries, C(2016) 1084, OJ C 74, 26.2.2016, p. 4-10. The Commission may consult the group on any matter relating to marine and fisheries biology, fishing gear technology, fisheries economics, fisheries governance, ecosystem effects of fisheries, aquaculture or similar disciplines. This report focuses on the application of the landing obligation on the fisheries targeting Venus clams in the Northern Adriatic SeaPeer Reviewe