The different paths to entropy

In order to undestand how the complex concept of entropy emerged,we propose a trip towards the past reviewing the works of Clausius, Boltzmann, Gibbs and Planck. In particular, since the Gibbs's work is not very well known, we present a detailed analysis, recalling the three definitions of the entropy that Gibbs gives. May be one of the most important aspect of the entropy is to see it as a thermodynamic potential like the other thermodynamic potentials as proposed by Callen. We close with some remarks on entropy and irreversibility.Comment: 32 page

Ambiguity Measures for preference-based decision viwewpoints

This paper examines the ambiguity of subjective judgments, which are represented by a system of pairwise preferences over a given set of alternatives. Such preferences are valued with respect to a set of reasons, in favor and against the alternatives, establishing a complete judgment, or viewpoint, on how to solve the decision problem. Hence, viewpoints entail particular decisions coming from the system of preferences, where the preference-based reasoning of a given viewpoint holds according to its soundness or coherence. Here we explore such a coherence under the frame of ambiguity measures, aiming at learning viewpoints with highest preference-score and minimum ambiguity. We extend existing measures of ambiguity into a multi-dimensional fuzzy setting, and suggest some future lines of research towards measuring the coherence or (ir)rationality of viewpoints, exploring the use of information measures in the context of preference learning

La incuestionabilidad del riesgo

Con anterioridad a la década de 1980, la literatura especializada en análisis y gestión del riesgo estaba dominada por la llamada visión tecnocrática o dominante. Esta visión establecía que los desastres naturales eran sucesos físicos extremos, producidos por una naturaleza caprichosa, externos a lo social y que requerían soluciones tecnológicas y de gestión por parte de expertos. Este artículo se centra en desarrollar una nueva explicación para entender la persistencia hegemónica de la visión tecnocrática basada en el concepto de incuestionabilidad del riesgo. Esta propuesta conceptual hace referencia a la incapacidad y desidia de los expertos, científicos y tomadores de decisiones en general (claimmakers) de identificar y actuar sobre las causas profundas de la producción del riesgo ya que ello conllevaría a cuestionar los imperativos normativos, las necesidades de las elites y los estilos de vida del actual sistema socioeconómico globalizado.Before de 1980s, the natural hazard analysis and management specialized literature was dominated by the so called "dominant" or "technocratic" view. Such perspective had established that natural disasters are extreme physical events caused by a whimsical nature and that these events are external to society. These events required technological and management solutions developed by experts. The current article aims at addressing a new explanatory component in the hegemonic persistence of the technocratic view. Such assumption was based on the "unquestionability of the risk" concept. It is stated that the "unquestionability of the risk" is the overall incapacity and neglect of experts, scientists and decision makers to identify and act over the deep causes of risk production, since it would make them question the normative imperatives and the demands from the elite as well as the life style in nowadays globalized socio-economic system

The BRICS in the Global Order: A New Political Agenda?

Regarding the BRICS (Brazil, Russia, India, China and South Africa) it’s important to analyze comparatively the new power cycle in order to understand not only the impact of the world crisis as well as the relationship between the official political discourses and the economic instability. Actually, the trade liberalization and economic interdependence accompanied with an uncertain international system are putting pressure to the BRICS with their own agendas for global order in seeking for a balance and also to regain a new political and economical dynamic for the promotion of new strategies

Socio-Economic Instability and the Scaling of Energy Use with Population Size

The size of the human population is relevant to the development of a sustainable world, yet the forces setting growth or declines in the human population are poorly understood. Generally, population growth rates depend on whether new individuals compete for the same energy (leading to Malthusian or density-dependent growth) or help to generate new energy (leading to exponential and super-exponential growth). It has been hypothesized that exponential and super-exponential growth in humans has resulted from carrying capacity, which is in part determined by energy availability, keeping pace with or exceeding the rate of population growth. We evaluated the relationship between energy use and population size for countries with long records of both and the world as a whole to assess whether energy yields are consistent with the idea of an increasing carrying capacity. We find that on average energy use has indeed kept pace with population size over long time periods. We also show, however, that the energy-population scaling exponent plummets during, and its temporal variability increases preceding, periods of social, political, technological, and environmental change. We suggest that efforts to increase the reliability of future energy yields may be essential for stabilizing both population growth and the global socio-economic system

Um modelo para análise energética de agroecossistemas

Este trabalho apresenta a argumentação teórica da entropia como referencial para análise de agroecossistemas, propõe uma metodologia para tal análise baseada no estudo dos fluxos de energia, e discute os valores energéticos dos fatores físicos da produção agrícola. E mostrado, ainda, o exemplo da aplicação do modelo a um sistema de produção de milho adotado no Estado de Santa Catarina, Brasil