Problemas y estrategias para combatir las pandemias a la luz de la gripe aviar de 2005

Este análisis se centra en la importancia de poner en marcha una estrategia de lucha contra enfermedades infecciosas que tenga en cuenta los patrones de interacción humana al intentar combatir una pandemia en la sociedad moderna. Este análisis estudia la importancia de considerar los patrones de contacto social de los individuos de una región tanto al decidir qué estrategia de vacunación emplear como al intentar limitar los contactos en la región en caso de una gran pandemia. El análisis incluye una breve introducción a los brotes recientes de nuevas enfermedades infecciosas, como el SIDA y el SARS. Llegamos a la conclusión de que a la hora de diseñar una estrategia de vacunación para impedir una mayor propagación de una enfermedad resulta más efectivo tener en cuenta los patrones de interacción social (centrándose en quienes viajan largas distancias, en individuos con gran cantidad de contactos diarios y en aquéllos con mayor riesgo de entrar en contacto con individuos contagiosos, como quienes trabajan en sanidad) que adoptar un enfoque más aleatorio o centrado en los individuos más vulnerables

Patrones de contacto social y dinámica de las enfermedades

Las enfermedades transmisibles han constituido históricamente una amenaza muy grave para la sociedad. La epidemia del SIDA, el brote de SARS y la posibilidad del bioterrorismo han dejado claro que esta amenaza sigue presente. La creciente amenaza que las enfermedades infecciosas suponen para la sociedad contemporánea es en gran medida el resultado de nuestro estilo de vida moderno, sobre todo a causa del gran número de interacciones sociales a nivel global posibles en un corto período de tiempo. Más que nunca, los patrones de contacto social son fundamentales para entender la dinámica de las enfermedades infecciosas. En este documento se comentan los principales aspectos de los modelos epidemiológicos y de los patrones de contacto que deben tenerse en cuenta y se destaca la interacción existente entre las características de las enfermedades y los patrones de interacción social. También se discuten las similitudes y diferencias existentes entre los patrones de interacción social de la sociedad actual y las sociedades de antaño y las consecuencias de ambas en la dinámica de las enfermedades

Modelling the evolution of a bipartite network-Peer referral in interlocking directorates

Abstract in Undetermined A central part of relational ties between social actors is constituted by shared affiliations and events. The action of joint participation reinforces personal ties between social actors as well as mutually shared values and norms that in turn perpetuate the patterns of social action that define groups. Therefore the study of bipartitenetworks is central to social science. Furthermore, the dynamics of these processes suggests that bipartitenetworks should not be considered static structures but rather be studied over time. In order to model the evolution of bipartitenetworks empirically we introduce a class of models and a Bayesian inference scheme that extends previous stochastic actor-oriented models for unimodal graphs. Contemporary research on interlockingdirectorates provides an area of research in which it seems reasonable to apply the model. Specifically, we address the question of how tie formation, i.e. director recruitment, contributes to the structural properties of the interlockingdirectoratenetwork. For boards of directors on the Stockholm stock exchange we propose that a prolific mechanism in tie formation is that of peerreferral. The results indicate that such a mechanism is present, generating multiple interlocks between boards

Peer clustering of exercise and eating behaviours among young adults in Sweden: a cross-sectional study of egocentric network data

Background Research suggests that the growing prevalence of obesity may be related to the influence of the health behaviours of peers. We look at clustering of exercise and eating behaviours amongst a previously unstudied group, young adults in Sweden. Previous research has mainly been conducted in the United States and Britain, countries that have relatively high rates of obesity. Methods Using ego-alter dyads from the egocentric network data as the unit of analysis, we conduct logistic regressions to investigate the association between ego and alter exercise and eating behaviours. Results Respondents have a significantly greater probability of engaging in regular exercise and eating healthily if a nominated peer also does so. Furthermore, the degree to which this behavior is shared is modulated by the strength of the relationship between the two individuals, with a greater probability of engaging in these behaviours observed when the relationship with the nominated peer is strong relative to when the relationship is weak. However, we find that ego-alter homogeneity in terms of gender and migration status was not associated with a significantly greater probability of behaving in a similar manner to a nominated peer. Furthermore, the status of the nominated peer as a relative or not did not impact the probability that the ego would engage in similar health behaviours to that alter. Conclusions We observe strong associations between ego and alter health behaviours for young adults, consistent with previous research. Although we cannot draw causal inferences, these results suggest that the health behaviours of an individual’s peers may play a role in shaping their own health behaviours

Social influence and corporate behaviour a case study of interdependent decision-making in Sweden's publicly traded firms

In the course of a few months in 1997, about 20 per cent of Stockholm Stock Exchange's primary‐list firms transferred to the Exchange's secondary list due to a new tax policy. Drawing on a theory of social influence, we suggest that the transfer decisions depended both on the firms' social embeddedness with other firms in the population at risk and their economic predisposition to make such transfers. We model such transfer decisions as a continuous stochastic process by utilizing event‐history techniques. The analysis is performed on data that are exceptionally good for both network and event‐history analysis: they include the whole population of firms at risk in a complete observation window. Our results indicate that the decision to transfer was a function of the firms' economic predisposition and their social embeddedness in terms of board interlocks. The special features of our data in combination with our findings suggest that our results should have a broader application: Ignoring social interdependencies at the micro level when attempting to explain the rationale for strategic decisions at the firm level in a group of firms belonging to the same system is likely to miss some of the most important driving forces behind strategic decision making.The research reported in this paper has been carried out within the project Structural Dynamics and Diffusion Processes in Swedish Business, financed by The Bank of Sweden Tercentenary Foundation. Financial support from the Swedish Council for Research in the Humanities and Social Sciences and the Swedish Foundation for International Cooperation in Research and Higher Education is also gratefully acknowledged

The Web of Human Sexual Contacts

Many ``real-world'' networks are clearly defined while most ``social'' networks are to some extent subjective. Indeed, the accuracy of empirically-determined social networks is a question of some concern because individuals may have distinct perceptions of what constitutes a social link. One unambiguous type of connection is sexual contact. Here we analyze data on the sexual behavior of a random sample of individuals, and find that the cumulative distributions of the number of sexual partners during the twelve months prior to the survey decays as a power law with similar exponents $\alpha \approx 2.4$ for females and males. The scale-free nature of the web of human sexual contacts suggests that strategic interventions aimed at preventing the spread of sexually-transmitted diseases may be the most efficient approach.Comment: 7 pages with 2 eps figures. Latex file. For more details or for downloading the PDF file of the published article see http://polymer.bu.edu/~amaral/WebofContacts.html . For more results on teh structure of complex networks see http://polymer.bu.edu/~amaral/Networks.htm

Conflicting Climate Change Frames in a Global Field of Media Discourse

Reducing global emissions will require a global cosmopolitan culture built from detailed attention to conflicting national climate change frames (interpretations) in media discourse. The authors analyze the global field of media climate change discourse using 17 diverse cases and 131 frames. They find four main conflicting dimensions of difference: validity of climate science, scale of ecological risk, scale of climate politics, and support for mitigation policy. These dimensions yield four clusters of cases producing a fractured global field. Positive values on the dimensions show modest association with emissions reductions. Data-mining media research is needed to determine trends in this global field.Peer reviewe