The Stability of the Roommate Problem Revisited

The lack of stability in some matching problems suggests that alternative solution concepts to the core might be applied to find predictable matchings. We propose the absorbing sets as a solution for the class of roommate problems with strict preferences. This solution, which always exists, either gives the matchings in the core or predicts some other matchings when the core is empty. Furthermore, it satisfies an interesting property of outer stability. We also characterize the absorbing sets, determine their number and, in case of multiplicity, we find that they all share a similar structure.roommate problem, core, absorbing sets

Admissible Hierachic Sets

In this paper we present a solution concept for abstract systems called the admissible hierarchic set. The solution we propose is a refinement of the hierarchic solution, a generalization of the von Neumann and Morgenstern solution. For finite abstract systems we show that the admissible hierarchic sets and the von Neumann and Morgenstern stable sets are the only outcomes of a coalition formation procedure (Wilson, 1972 and Roth, 1984). For coalitional games we prove that the core is either a vN&M stable set or an admissible hierarchic set.abstract system, coalitional game, corem, hierarchic solution, subsolution, Von Neumann and Morgenstern stable set

Discriminating by Tagging: Artificial Distinction, Real Discrimination

We introduce a new variation of the hawk-dove game suggested by an experiment that studies the behavior of a group of domestic fowls when a subgroup has been marked. Speci cally we consider a population formed by two types of individual that fail to recog- nize their own type but do recognize the other type. In this game we find two evolutionarily stable strategies. In each of them, individuals from one type are always attacked more, whatever proportion of the population they represent. Our theoretical results are consistent with the conclusions drawn from experimental work, where marked fowls received more pecks than their unmarked counterparts.

Aeropalinología de la ciudad de Yerba Buena, provincia de Tucumán (Argentina)

Aeropalinología de la ciudad de Yerba Buena, provincia de Tucumán (Argentina). Durante los años 1999 - 2002 se llevó a cabo la primera caracterización aerobiológica de la ciudad de Yerba Buena. El muestreo atmosférico se realizó con un captador gravimétrico de tipo Durham. El análisis de las muestras permitió la identificación de 46 tipos polínicos. Los granos de polen más relevantes en el muestreo son de especies cultivadas como Cupressaceae, Morus sp., Broussonetia sp., Fraxinus sp., Liquidambar sp., Salix sp. y Pinus sp. Desde julio a octubre se obtuvo el mayor registro de polen atmosférico con el 70,84 % anual, con una predominancia de granos de polen de especies arbóreas, el 25,05 % de noviembre a abril con un aporte principalmente de granos de polen de especies herbáceas y el 3,57 % de mayo a junio sin contribuciones dominantes de algún tipo polínico. Se elaboró un calendario polínico basado en los 17 tipos de polen de mayor registro atmosférico y se lo comparó con calendarios polínicos obtenidos en ciudades del país. La floración en las Sierra del San Javier en Tucumán, es marcadamente estacional con una acumulación de más de 70% de las especies que florecen en el período primaveral. El muestreo continuado a lo largo de 3 años ha permitido observar que las variaciones polínicas estacionales de la atmósfera de la ciudad de Yerba Buena se hallan en relación con los factores fenológicos y meteorológicos propios de cada año

Software Design Guidelines for Usability

For years, the Human Computer Interaction (HCI) community has crafted usability guidelines that clearly define what
characteristics a software system should have in order to be easy to use. However, in the Software Engineering (SE)
community keep falling short of successfully incorporating these recommendations into software projects. From a SE
perspective, the process of incorporating usability features into software is not always straightforward, as a large number
of these features have heavy implications in the underlying software architecture. For example, successfully including an
“undo” feature in an application requires the design and implementation of many complex interrelated data structures and
functionalities. Our work is focused upon providing developers with a set of software design patterns to assist them in the
process of designing more usable software. This would contribute to the proper inclusion of specific usability features
with high impact on the software design. Preliminary validation data show that usage of the guidelines also has positive
effects on development time and overall software design quality

Absorbing Sets in Coalitional Systems

The purpose of this paper is twofold: First, to present an approach and a solution for analyzing the stability of coalition structures: We define a coalitional system (a set and a binary relation on that set) that explains the transitions between coalition structures and we propose to solve these systems using the absorbing sets solution for abstract systems. Second, to perform an analysis of this approach to evidence its utility in determining the stable coalition structures for some socioeconomic problems. We find that the absorbing sets solution efficiently solves this class of coalitional systems.coalition structures, coalitional systems, absorbing sets solution

Perfil de seguridad de los nuevos fármacos frente al virus de la hepatitis C

La infección por el virus de la hepatitis C es un problema de salud de primera magnitud a nivel mundial. Hasta hace poco tiempo, el tratamiento tradicional de esta patología estaba restringido a la terapia combinada con interferón pegilado y ribavirina, y en el caso de que el virus de la hepatitis C fuera genotipo 1, se podían añadir a este esquema boceprevir o telaprevir. Estos esquemas de tratamiento se asocian a numerosas y graves reacciones adversas, que en algunos casos pueden obligar a suspender el tratamiento. En los últimos meses se dispone de nuevos fármacos antivirales de acción directa frente al virus de la hepatitis C, como simeprevir, sofosbuvir y daclatasvir, que presentan un perfil de seguridad más favorable que los tratamientos anteriores. Pretendemos conocer la seguridad de los nuevos fármacos antivirales de acción directa frente al virus de la hepatitis C simeprevir, sofosbuvir y daclatasvir y detectar reacciones adversas no descritas previamente. Estudio observacional, retrospectivo, de una cohorte de 39 pacientes mayores de 18 años, pertenecientes al Hospital Clínico Universitario de Valladolid, en tratamiento con simeprevir, sofosbuvir o daclatasvir. Los datos sociodemográficos, clínicos y farmacoterapéuticos de los pacientes se obtuvieron de sus historias clínicas informatizadas y de las hojas de registro de dispensaciones del Servicio de Farmacia del hospital. Se registraron un total de 53 reacciones adversas distintas, en su mayoría de carácter leve y descritas en bibliografía previa; la reacción adversa más frecuente fue la anemia. Concluimos que Simeprevir, sofosbuvir y daclatasvir son nuevos fármacos para el tratamiento de la hepatitis C que presentan, en apariencia, un perfil de seguridad más favorable que los anteriores.Departamento de Biología Celular, Histología y FarmacologíaMáster en Investigación en Ciencias de la Salu

El rol de la etimología en la enseñanza de los modismos relacionados con los colores en una L2

Teaching figurative language, in general, and idioms, in particular, is one of the most controversial and difficult areas in L2 teaching, as it seems to be a big challenge from a cultural point of view and, subsequently, from a pedagogical one. With regard to idioms related to colours, these expressions differ highly depending on whether their origin is Spanish or Anglo-Saxon. Examples ranging from colours such as white, black and red to blue, yellow and green will be the axis of our study. Through etymology we will be able to ascertain the root of these fixed expressions and provide some tips regarding their teachability/learnability. The use of etymology as a didactic tool, combined with illustrations, games, and dynamic exercises, will help students to understand these idioms, which are the reflection of a culture.La enseñanza del lenguaje figurado, en general, y de los modismos, en particular, es uno de los temas más difíciles y polémicos en la enseñanza de L2, ya que se considera un obstáculo desde un punto de vista cultural y, por tanto, pedagógico. En cuanto a los modismos que incluyen colores en su articulación, estas expresiones difieren sustancialmente dependiendo de los orígenes que se arraigan en la cultura española o anglosajona. A este respecto, el eje principal de nuestro estudio serán ejemplos que oscilan desde algunos de los colores, como el blanco, negro y rojo hasta el azul, amarillo y verde. A través de la etimología podremos establecer lo esencial de estos modismos y ofrecer alguna sugerencia respecto a la enseñanza y el aprendizaje de los mismos. El uso de la etimología como herramienta didáctica en conjunto con ilustraciones, juegos, y ejercicios dinámicos ayudará a los estudiantes a entender estos modismos, reflejo de una cultura

Teaching management information systems with blended learning methods.

The aim of this case-study is to show the creation and development of a virtual environment for an information systems subject. In order to prepare this work, we worried about some topics related with differences between traditional classroom teaching and web-based learning (WBL). Our paper is divided in two sections and finalize with some comments about our experience in blended learning methods for teaching management information systems. In the first part of this case-study, we try to explain some important constraints of these features. The second part shows our experience in building a virtual environment for our “Introduction to management information systems” subject in the Aula Virtual, the web-based environment of the Universidad de Cantabria in Spain

Determinants of International R&D Outsourcing: The Role of Trade

This paper investigates the determinants of international R&D outsourcing, in particular the role of trade. We construct a monopolistic competition model with heterogeneous firms where outsourcing increases a firm’s fixed transaction as well as its productivity. Financial constraints affect the decision to outsource R&D more to non-exporters than to exporters. In contrast, exporters are more sensitive to a lack of information because they have higher losses when there is technology leakage. We test these predictions using a panel database of Spanish companies. The results highlight the relevance of information in competitive markets, and the role of trade to induce companies to engage in other globalization strategies