Econofísica: En busca de un caballo perfectamente esférico y de masa despreciable

En este artículo, se analiza a través de símiles históricos el estado de la contribución de la Física a la Economía. Para ello se hace un repaso del modo de funcionamiento de la Física, o mejor dicho, del modo de proceder de los físicos. Ésta es la principal aportación de una ciencia a la otra: una forma diferente de aproximarse a los problemas complejos a los enfrenta la economía. En la discusión planteamos, de estos problemas, los que consideramos llevan a cabo mediante sistemas informatizados, y la necesidad de, llegado al grado de complejidad que tienen tanto la economía como la ciencia económica en la actualidad, una necesaria revolución en la forma de “mirar” de los economistas. Con ello proponemos que lo que se necesita en Economía es lo que tantas veces se ha buscado (y encontrado) en física: un modelo o una serie de modelos muy sencillos que capten, de manera totalmente nueva, la “esencia” del problema. Este modelo, el caballo esférico de masa despreciable, aunque erróneo (como los anteriores), será úti

Non-extensive radiobiology

The expression of survival factors for radiation damaged cells is based on probabilistic assumptions and experimentally fitted for each tumor, radiation and conditions. Here we show how the simplest of these radiobiological models can be derived from the maximum entropy principle of the classical Boltzmann-Gibbs expression. We extend this derivation using the Tsallis entropy and a cutoff hypothesis, motivated by clinical observations. A generalization of the exponential, the logarithm and the product to a non-extensive framework, provides a simple formula for the survival fraction corresponding to the application of several radiation doses on a living tissue. The obtained expression shows a remarkable agreement with the experimental data found in the literature, also providing a new interpretation of some of the parameters introduced anew. It is also shown how the presented formalism may has direct application in radiotherapy treatment optimization through the definition of the potential effect difference, simply calculated between the tumour and the surrounding tissue.Comment: 8 pages, 1 figure. Sent to MaxEnt 2010. To be submitted for publicatio

Evaluación de la diversidad de Quirópteros en el Paisaje Terrestre Protegido Mesas de Moropotente.

Se describe y compara la riqueza y diversidad de murciélagos en los bosques de carbón, bosque de roble, bosque de galería y huerto caseros (clasificado como un sistema agroforestal simultánea) en el Paisaje terrestre Protegido Mesas de Moropotente en el Departamento de Estelí. Comparando dos épocas del año (Invierno- Verano) en diferentes estaciones de muestreos. Se capturaron un total de 323 especímenes, pertenecientes a tres familias, 16 géneros y 25 especies. Las especies más abundante fueron Artibeus jamaicensis, Dermanura phaeotis, Desmodus rotundus y Artibeus lituratus. De acuerdo con sus hábitos alimenticios se encontraron cuatro gremios tróficos: murciélagos frugívoros, insectívoros, nectarívoros, y hematófagos. Diversidad α el valor más alto fue en la época de invierno en la estación 1 bosque con dominancia de la especie del carbón (Acacia pennatual) (H’= 2.061). Mostró baja semejanza entre los tipos de bosque, lo cual podría deberse a las condiciones en los sitios de captur

Critical analysis of the European Union directive which regulates the use of biofuels: An approach to the Spanish case

In recent times, the global debate on the environment has been centered on CO2 emissions. This gas is the major cause of the “greenhouse effect” and people are more concerned with the idea that the emissions of this gas should be minimized. As a result of this concern, the Kyoto Protocol was enacted and subscribed to by many countries, setting the maximum gas emissions for them. Fossil fuels are a major source of CO2 emissions. For some years now The European Union has been seeking to promote some years now the use of biofuels as substitutes for diesel or petrol for transport purposes. As a result of this policy, in 2003 the European Union (EU) Directive 2003/30/EC [1] was developed with the aim of promoting the use of biofuels as a substitute for diesel or gasoline among European Union countries as well as to contribute to fulfilling the commitments acquired on climate change, security of supply in environmentally friendly conditions and the promotion of renewable energy sources. In order to achieve these goals, the directive forces all EU members to ensure that before December 31 of 2010 at least 5.75% of all gasoline and diesel fuels sold for transport purposes are biofuels. European Union countries have social and economic characteristics unique to themselves. The energy dependence on foreign sources, the features of the agricultural sector or the degree of industrialization varies greatly from one country to another. In this context, it is questionable whether the obligation imposed by this directive is actually achieving in its application uniform and/or identical goals in each of the countries involved and whether the actions of the various governments are also aligned with these goals. All these ideas were developed in a previous report (Sobrino and Monroy (2009) [2]). This report examines the possibility of using hydrogen as an alternative to fossil fuels and biofuels from a technical, economic and environmental point of view in the specific case of a European Union country: Spain

Propuestas para la construcción de un entendimiento nacional en materia fiscal

En este documento se aborda el desempeño económico y de las finanzas públicas de El Salvador, haciendo énfasis en la falta de una política fiscal sostenible que contribuya al desarrollo humano. Se ponen en cuestión los problemas estructurales de las finanzas públicas, al tiempo que presentan algunas medidas de política en materia de ingresos, gasto y gestión de la deuda pública para solucionarlos

Exploring European Citizens’ Resilience to Misinformation: Media Legitimacy and Media Trust as Predictive Variables

Building on the notion of an intangible resource, this research conceptualizes resilience as an intangible resource that can be ascribed to countries (governments and media) and explores its sources. After presenting the conceptual framework, the study uses cross-national comparable data from Eurobarometer to (a) determine whether a factor called “resilience to misinformation” can be composed of citizens’ attitudes and behaviors toward misinformation and be conceptualized and operationalized as an intangible asset, and (b) determine the extent to which other intangible assets regarding the media (legitimacy and trust) help predict resilience to misinformation. Based on statistical techniques, findings show that (a) it is possible to conceptualize “resilience to misinformation” as an intangible asset comprised of several items related to citizens’ awareness of misinformation, acknowledgment of the negative impact, and the development of skills to identify misinformation; (b) this intangible asset can be analyzed in relation to intangibles that derive from media performance, such as media legitimacy and trust in the media; and (c) media’s intangible assets seem to be more predictive of “resilience to misinformation” than sociodemographic variables. Based on the findings, this research proposes a conceptualization of “resilience to misinformation” as an intangible resource in the public sector. In addition, it highlights recommendations for the mainstream media on how to manage their intangible value while contributing to resilience to misinformation

Leveraging energy saving capabilities of current EEE interfaces via pre-coalescing

The low power idle mode implemented by Energy Efficient Ethernet (EEE) allows network interfaces to save up to 90% of their nominal energy consumption when idling. There is an ample body of research that recommends the use of frame coalescing algorithms—that enter the low power mode as soon as there is no more traffic waiting to be sent, and delay the exit from this mode until there is an acceptable amount of traffic queued—to minimize energy usage while maintaining an acceptable performance. However, EEE capable hardware from several manufactures delays the entrance to the low power mode for a considerable amount of time (hysteresis). In this paper we augment existing EEE energy models to account for the hysteresis delay and show that, using the configuration ranges provided by manufacturers, most existing EEE networking devices are unable to obtain significant energy savings. To improve their energy efficiency, we propose to implement frame coalescing directly at traffic sources, before reaching the network interface. We also derive the optimum coalescing parameters to obtain a given target energy consumption at the EEE device when its configuration parameters are known in advance.Agencia Estatal de Investigación | Ref. TEC2017-85587-

End-to-end active queue management with Named-Data Networking

The innovative information-based Named-Data Networking (NDN) architecture provides a good opportunity to rethink many of the design decisions that are taken for granted in the Internet today. For example, active queue management (AQM) tasks have been traditionally implemented in the routers to alleviate network congestion before their buffers fill up. However, AQM operations could be performed on an end-to-end basis by taking advantage of NDN features. In this paper, we provide an implementation of an AQM algorithm for the NDN architecture that we use to drive a classical AIMD-based congestion control protocol at the receivers. To accomplish this, we take advantage of the 64-bit Congestion Mark field present in the link layer of NDN packets to encode both rate and delay information about each transmission queue along a network path. In order to make the solution scalable, this information is delivered stochastically, guaranteeing that receivers get accurate and updated information about every pertinent queue. This information is enough to implement the well-known controlled delay (CoDel) AQM algorithm. Simulation results show that our client-located CoDel implementation is able to react to congestion when the bottleneck queuing delay surpasses the 5 ms target set by the usual in-network CoDel implementation and, at the same time, get a fair and efficient share of the available transmission capacityAgencia estatal de investigación | Ref. PID2020-113240RB-I00Universidade de Vigo/CISU

Propiedades psicométricas del Cuestionario de violencia Escolar: revisado (CUVE-R)

Los dos objetivos principales de este trabajo han sido disear una versin revisada y ampliada delCuestionario de Violencia Escolar (CUVE) (lvarez et al., 2006) y contrastar empricamente su validezde constructo. El Cuestionario de Violencia Escolar-Revisado (CUVE-R) fue aplicado a 646 estudiantesde Educacin Secundaria Obligatoria. Mediante anlisis factoriales confirmatorios, se pusierona prueba dos posibles modelos explicativos de la estructura factorial de la prueba. Los resultadosobtenidos sealan que ambos pueden representar aceptablemente bien la estructura del CUVE-R, sibien algo mejor el denominado modelo de ocho factores (Violencia de profesorado hacia alumnado,Violencia fsica directa entre estudiantes, Violencia fsica indirecta por parte del alumnado,Violencia verbal entre estudiantes, Violencia verbal del alumnado hacia el profesorado, Exclusinsocial, Disrupcin en el aula y Violencia a travs de las Nuevas Tecnologas de la Informacin y dela Comunicacin)