32 resultados para Social systems


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What are the best voting systems in terms of utilitarianism? Or in terms of maximin, or maximax? We study these questions for the case of three alternatives and a class of structurally equivalent voting rules. We show that plurality, arguably the most widely used voting system, performs very poorly in terms of remarkable ideals of justice, such as utilitarianism or maximin, and yet is optimal in terms of maximax. Utilitarianism is bestapproached by a voting system converging to the Borda count, while the best way to achieve maximin is by means of a voting system converging to negative voting. We study the robustness of our results across different social cultures, measures of performance, and population sizes.

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The 10 June 2000 event was the largest flash flood event that occurred in the Northeast of Spain in the late 20th century, both as regards its meteorological features and its considerable social impact. This paper focuses on analysis of the structures that produced the heavy rainfalls, especially from the point of view of meteorological radar. Due to the fact that this case is a good example of a Mediterranean flash flood event, a final objective of this paper is to undertake a description of the evolution of the rainfall structure that would be sufficiently clear to be understood at an interdisciplinary forum. Then, it could be useful not only to improve conceptual meteorological models, but also for application in downscaling models. The main precipitation structure was a Mesoscale Convective System (MCS) that crossed the region and that developed as a consequence of the merging of two previous squall lines. The paper analyses the main meteorological features that led to the development and triggering of the heavy rainfalls, with special emphasis on the features of this MCS, its life cycle and its dynamic features. To this end, 2-D and 3-D algorithms were applied to the imagery recorded over the complete life cycle of the structures, which lasted approximately 18 h. Mesoscale and synoptic information were also considered. Results show that it was an NS-MCS, quasi-stationary during its stage of maturity as a consequence of the formation of a convective train, the different displacement directions of the 2-D structures and the 3-D structures, including the propagation of new cells, and the slow movement of the convergence line associated with the Mediterranean mesoscale low.

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A simple model of diffusion of innovations in a social network with upgrading costs is introduced. Agents are characterized by a single real variable, their technological level. According to local information, agents decide whether to upgrade their level or not, balancing their possible benefit with the upgrading cost. A critical point where technological avalanches display a power-law behavior is also found. This critical point is characterized by a macroscopic observable that turns out to optimize technological growth in the stationary state. Analytical results supporting our findings are found for the globally coupled case.

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This article was delivered as an area-paper to the Critical Political Science Meeting of Bilbao, November the 15th 2008, which was organized by the Political Science Department of the UPV (University of the Basque Country). The paper introduces an updated and synthetic version of the model designed by S.M. Lipset and S. Rokkan in 1967 in order to identify the confrontational divides distinctive of European modernization and, in this way, trace the origins of modern party systems. The expanded model proposed is applied, on the one hand, to a variety of empirical cases, prominently the postransitional Spanish case; and on the other, shows its usefulness in order to better understand the distinctive structure of the social conflict of the globalization era.

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There is a concern that agriculture will no longer be able to meet, on a global scale, the growing demand for food. Facing such a challenge requires new patterns of thinking in the context of complexity and sustainability sciences. This paper, focused on the social dimension of the study and management of agricultural systems, suggests that rethinking the study of agricultural systems entails analyzing them as complex socio-ecological systems, as well as considering the differing thinking patterns of diverse stakeholders. The intersubjective nature of knowledge, as studied by different philosophical schools, needs to be better integrated into the study and management of agricultural systems than it is done so far, forcing us to accept that there are no simplistic solutions, and to seek a better understanding of the social dimension of agriculture. Different agriculture related problems require different policy and institutional approaches. Finally, the intersubjective nature of knowledge asks for the visualization of different framings and the power relations taking place in the decision-making process. Rethinking management of agricultural systems implies that policy making should be shaped by different principles: learning, flexibility, adaptation, scale-matching, participation, diversity enhancement and precaution hold the promise to significantly improve current standard management procedures.

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Rural depopulation and abandonment of farming activities have resulted in an intense transformation of the characteristic landscapes of Mediterranean mountains. A dynamic characterized by an intense process of expansion of forested cover in detriment to livestock and agricultural areas. This process, which produces effects such as biodiversity and cultural heritage loss and contributes to the spread of wildfires, can be mapped, quantified and described with high accuracy through the means of digital mapping, geographic information systems and landscape indexes. But what is the perception and valuation of these changes by the stakeholders involved in the management of these territories? This article attempts to answer this question in the protected area of Alta Garrotxa (Girona), where a strong correlation between landscape dynamics and their perception by the stakeholders is revealed. On the other hand, the valuation and future prospects produce diverse and often contradictory points of views that illustrate the existing difficulties to management

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We propose a class of models of social network formation based on a mathematical abstraction of the concept of social distance. Social distance attachment is represented by the tendency of peers to establish acquaintances via a decreasing function of the relative distance in a representative social space. We derive analytical results (corroborated by extensive numerical simulations), showing that the model reproduces the main statistical characteristics of real social networks: large clustering coefficient, positive degree correlations, and the emergence of a hierarchy of communities. The model is confronted with the social network formed by people that shares confidential information using the Pretty Good Privacy (PGP) encryption algorithm, the so-called web of trust of PGP.

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En aquest treball s'han estudiat diferents sistemes de recomanació, i s'han utilitzat per a veure com podrien arribar a recomanar pel·lícules als usuaris. Això s'ha realitzat dins del context de la recomanació web, un sistema mitjançant el qual es poden obtenir moltes dades dels usuaris, però que per altra banda requereix de temps de resposta ràpids.

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Se aplican métodos ensayados en otros países (Scenic Beauty Estimation Method, SBE) para la determinación de las cualidades estéticas de masas forestales de interés recreativo a parcelas en diversas localizaciones del haya en Cataluña, abarcando diferencias significativas en estación, origen, edad y forma de masa. Las valoraciones se refieren a las cualidades estéticas de los rodales de haya vistos desde el interior del bosque, es decir, tal como son apreciados por parte de los visitantes de los montes. Las valoraciones se obtienen a través de paneles de observadores en sesiones fotográficas, se transforman a una escala común y se relacionan mediante análisis de regresión a las variables dasométricas tomadas en las parcelas de inventario. El desarrollo de modelos estadísticos que describen preferencias sociales permite medir la aportación de las diferentes variables dasométricas a la mejora estética de las masas de haya, y puede servir como guía en la ordenación de hayedos en que el uso público sea predominante o muy importante.

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El paisaje puede ser visto como la expresión territorial del metabolismo que cualquier sociedad mantiene con los sistemas naturales que la sustentan. Uno de los caminos para comprender cómo y por qué la intervención humana cambia la configuración del territorio consiste en analizar los flujos energéticos del intercambio metabólico de la economía con su entorno ambiental, y en identificar los impactos ecológicos que se imprimen en él. Este trabajo busca verificar, mediante la contabilidad del metabolismo social, y el empleo diacrónico de diversos índices desarrollados por la ecología del paisaje, que el enorme incremento de energía externa empleada por los sistemas agrarios tras la “revolución verde”, y la drástica reducción de su eficiencia, están estrechamente relacionados con los cambios de uso del suelo que han degradado considerablemente los tradicionales paisajes agrarios en mosaico del Mediterráneo. El recurso a flujos biofísicos externos, y el abandono del manejo integrado del territorio, han comportado una pérdida de la estructura funcional de la matriz territorial y de su conectividad ecológica. Los resultados obtenidos en cinco municipios de la comarca catalana del Vallès corroboran la estrecha relación existente durante los últimos 150 años entre la eficiencia energética y territorial, y el estado ecológico del paisaje.

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We propose an innovative, integrated, cost-effective health system to combat major non-communicable diseases (NCDs), including cardiovascular, chronic respiratory, metabolic, rheumatologic and neurologic disorders and cancers, which together are the predominant health problem of the 21st century. This proposed holistic strategy involves comprehensive patient-centered integrated care and multi-scale, multi-modal and multi-level systems approaches to tackle NCDs as a common group of diseases. Rather than studying each disease individually, it will take into account their intertwined gene-environment, socio-economic interactions and co-morbidities that lead to individual-specific complex phenotypes. It will implement a road map for predictive, preventive, personalized and participatory (P4) medicine based on a robust and extensive knowledge management infrastructure that contains individual patient information. It will be supported by strategic partnerships involving all stakeholders, including general practitioners associated with patient-centered care. This systems medicine strategy, which will take a holistic approach to disease, is designed to allow the results to be used globally, taking into account the needs and specificities of local economies and health systems.

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How did farmers maintain soil fertility as they cultivated the same land over decades and centuries? How did they transfer energy and nutrients (nitrogen, potassium, phosphorous) across the landscape to fertilize crops? How did farmers structure landscapes (field, pasture, woodland) to sustain communities, ensure long-term productivity, and produce profits? We summarize in this article the results of the ongoing research on the last stage of organic agriculture in Catalonia carried out by our project. We also outline the forthcoming steps to continue our research.

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This paper describes Question Waves, an algorithm that can be applied to social search protocols, such as Asknext or Sixearch. In this model, the queries are propagated through the social network, with faster propagation through more trustable acquaintances. Question Waves uses local information to make decisions and obtain an answer ranking. With Question Waves, the answers that arrive first are the most likely to be relevant, and we computed the correlation of answer relevance with the order of arrival to demonstrate this result. We obtained correlations equivalent to the heuristics that use global knowledge, such as profile similarity among users or the expertise value of an agent. Because Question Waves is compatible with the social search protocol Asknext, it is possible to stop a search when enough relevant answers have been found; additionally, stopping the search early only introduces a minimal risk of not obtaining the best possible answer. Furthermore, Question Waves does not require a re-ranking algorithm because the results arrive sorted

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The paper analyses the link between human capital and regional economic growth in the European Union. Using different indicat The importance of effective and efficient mobility in large cities is becoming essential for planners and citizens due to its impact in terms of social, economic and geographic development. The aim of this research is to determine factors explaining urban transport systems by estimating aggregate supply and demand equations for 45 large European cities. Supply and Demand equations are separately and jointly determined using OLS and SUR estimation models. On one hand, our findings suggest the importance of economic variables on the supply of public transport. On the other, we highlight the role of those factors influencing the generalized cost of transport as main drivers of demand for public transit. Additionally, regional variables are introduced to capture institutional heterogeneity in this service, and we find that regional patterns are powerful explanatory determinants of urban transportation systems in Europe.

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Health and inequalities in health among inhabitants of European cities are of major importance for European public health and there is great interest in how different health care systems in Europe perform in the reduction of health inequalities. However, evidence on the spatial distribution of cause-specific mortality across neighbourhoods of European cities is scarce. This study presents maps of avoidable mortality in European cities and analyses differences in avoidable mortality between neighbourhoods with different levels of deprivation. Methods: We determined the level of mortality from 14 avoidable causes of death for each neighbourhood of 15 large cities in different European regions. To address the problems associated with Standardised Mortality Ratios for small areas we smooth them using the Bayesian model proposed by Besag, York and Mollié. Ecological regression analysis was used to assess the association between social deprivation and mortality. Results: Mortality from avoidable causes of death is higher in deprived neighbourhoods and mortality rate ratios between areas with different levels of deprivation differ between gender and cities. In most cases rate ratios are lower among women. While Eastern and Southern European cities show higher levels of avoidable mortality, the association of mortality with social deprivation tends to be higher in Northern and lower in Southern Europe. Conclusions: There are marked differences in the level of avoidable mortality between neighbourhoods of European cities and the level of avoidable mortality is associated with social deprivation. There is no systematic difference in the magnitude of this association between European cities or regions. Spatial patterns of avoidable mortality across small city areas can point to possible local problems and specific strategies to reduce health inequality which is important for the development of urban areas and the well-being of their inhabitants