Selecting the W Matrix. Parametric vs Nonparametric Approaches

In spatial econometrics, it is customary to specify a weighting matrix, the so-called W matrix, just choosing one matrix from the different types of matrices a user is considering (Anselin, 2002). In general, this selection is made a priori, depending on the user’s judgment. This decision is extremely important because if matrix W is miss-specified in some way, parameter estimates are likely to be biased and they will be inconsistent in models that contain some spatial lag. Also, for models without spatial lags but where the random terms are spatially autocorrelated, the obtaining of robust standard estimates of the errors will be incorrect if W is miss-specified. Goodness-of-fit tests may be used to chose between alternative specifications of W. Although, in practice, most users impose a certain W matrix without testing for the restrictions that the selected spatial operator implies. In this paper, we aim to establish a nonparametric procedure where the chosen by objective criteria. Our proposal is directly related with the Theory of Information. Specifically, the selection criterion that we propose is based on objective information existing in the data, which does not depend on the investigator’s subjectivity: it is a measure of conditional entropy. We compare the performance of our criteria against some other alternative like the J test of Davidson and McKinnon or a likelihood ratio obtained in a maximum likelihood framework.

Análisis de las propuestas de los partidos políticos en materia de Educación Infantil

Treball Final de Grau en Mestre o Mestra d'Educació Infantil. Codi: MI1040. Curs acadèmic 2015-2016El presente Trabajo de Fin de Grado (TFG) tiene como objetivo principal realizar un análisis de las propuestas actuales de los siguientes partidos políticos: Partido Socialista Obrero Español, Partido Popular, Ciudadanos y Podemos sobre la Educación Infantil en España. El proyecto se plantea a partir de una contextualización de la situación social en España, después de pasar por una gran crisis económica y habiendo sufrido recortes en diferentes sectores sociales, centrándonos sobre todo en la educación infantil, para más adelante observar las propuestas políticas con referencia a ésta. Posteriormente, se realizará un análisis de cada una de ellas para comprobar si son adecuadas o no a la situación actual, y si realmente la política española le da la importancia que se merece a la Educación Infantil. Todo ello a partir de fuentes primarias como periódicos, revistas oficiales, informes técnicos y documentos oficiales de instituciones públicas

Unveiling the origin of the radio emission in radio-quiet quasars

The origin of the radio emission in radio-quiet quasars (RQQs) has been a matter of debate for a long time. It is not well understood whether the emission is caused by star formation in the host galaxy or by black hole activity of the active galactic nuclei (AGN). We shed some light on these questions using the Very Long Baseline Interferometry (VLBI) technique to search for RQQs in the field of the Cosmological Evolution Survey (COSMOS). The extensive multi-wavelength coverage of the field (from radio to X-rays) was used to classify RQQs, and the milli-arcsecond resolution of VLBI provides a direct way to identify AGNs. In a sample of 18 RQQs we detected 3 using the Very Long Baseline Array (VLBA) at 1.4 GHz. In this letter we report for the first time on a sample of RQQs with a measured lower limit on the fraction of radio emission coming from the AGN, thus demonstrating that the radio emission of at least some RQQs is dominated by an AGN.Comment: 4 pages, letter to the editor, accepted for publication in A&

A HOLISTIC REDUNDANCY- AND INCENTIVE-BASED FRAMEWORK TO IMPROVE CONTENT AVAILABILITY IN PEER-TO-PEER NETWORKS

Peer-to-Peer (P2P) technology has emerged as an important alternative to the traditional client-server communication paradigm to build large-scale distributed systems. P2P enables the creation, dissemination and access to information at low cost and without the need of dedicated coordinating entities. However, existing P2P systems fail to provide high-levels of content availability, which limit their applicability and adoption. This dissertation takes a holistic approach to device mechanisms to improve content availability in large-scale P2P systems. Content availability in P2P can be impacted by hardware failures and churn. Hardware failures, in the form of disk or node failures, render information inaccessible. Churn, an inherent property of P2P, is the collective effect of the users’ uncoordinated behavior, which occurs when a large percentage of nodes join and leave frequently. Such a behavior reduces content availability significantly. Mitigating the combined effect of hardware failures and churn on content availability in P2P requires new and innovative solutions that go beyond those applied in existing distributed systems. To addresses this challenge, the thesis proposes two complementary, low cost mechanisms, whereby nodes self-organize to overcome failures and improve content availability. The first mechanism is a low complexity and highly flexible hybrid redundancy scheme, referred to as Proactive Repair (PR). The second mechanism is an incentive-based scheme that promotes cooperation and enforces fair exchange of resources among peers. These mechanisms provide the basis for the development of distributed self-organizing algorithms to automate PR and, through incentives, maximize their effectiveness in realistic P2P environments. Our proposed solution is evaluated using a combination of analytical and experimental methods. The analytical models are developed to determine the availability and repair cost properties of PR. The results indicate that PR’s repair cost outperforms other redundancy schemes. The experimental analysis was carried out using simulation and the development of a testbed. The simulation results confirm that PR improves content availability in P2P. The proposed mechanisms are implemented and tested using a DHT-based P2P application environment. The experimental results indicate that the incentive-based mechanism can promote fair exchange of resources and limits the impact of uncooperative behaviors such as “free-riding”

Tungsten and the Vestiges of Colonialism in Peru

El artículo propone una reflexión frente a las diversas expresiones del colonialismo que se manifiestan en El tungsteno, la novela social de Vallejo, destacando su plano político y estable­ciendo un paralelo con el pensamiento crítico de Aimé Césaire. Se busca de­mostrar que la iniciativa de reivindicar al mundo indígena desde el marxismo-leninismo constituye, en últimas, una variable más del colonialismoThis article proposes a reflection before different expressions of Colonialism, which are shown in Tungsten, Vallejo’s social novel, highlighting its political plane and setting up a parallel with Aimé Césaire’s critical thinking. It searches for demons­trating that the initiative of defending the indigenous world from Marxist-Lenin theories constitutes one more variable of colonialism

Anotaciones sobre el sujeto lírico en la poesía de Raúl Gómez Jattin (1945-1997)

El artículo aborda la reflexión en torno al sujeto lírico en tanto categoría de análisis lingüístico y literario, a través de una relectura de ocho piezas poéticas de Raúl Gómez Jattin, escritas en la década de los 80 del siglo pasado. Se describen algunos aspectos formales y semánticos de los poemas seleccionados y se propone un plano de interpretación de los mismos con base en los rasgos biográficos del autor y el lenguaje estético producto de su condición existencial

Applied anthropology for international business: convergence and divergence

Este artículo plantea una reflexión en torno a la aplicación de las teorías y métodos de la antropología en algunos aspectos prácticos de la administra­ción que interesan a los negocios internacionales, tales como como la cultura organizacional, la investigación de mercados y la dimensión intercultural que caracteriza a esta actividad en el ámbito global. Se exploran algunas fuentes bibliográficas y aportes de investigadores representativos que ilustran sobre el desarrollo profesional y académico y los debates que se generan en el interior de esta sub-especialidad de la antropología en la Contemporaneidad. Se con­cluye que instrumentalizar el conocimiento científico sobre el comportamiento cultural al servicio del poder corporativo plantea problemas de orden ético. This article reflects upon the application of anthropology theories and methods over certain practical administration aspects that are of interest to international business, such as organizational culture, market research and the intercultural dimension that characterizes this activity in a global environment. In order to illus­trate this, some bibliographical sources and contributions made by representative researchers on professional and academic development are explored as well as the internal debates that are happening within this sub-spatiality of Anthropology now a days. It is concluded that when scientific knowledge is applied over the cultural behavior to the service of corporate power, it those bring with it ethical issues.Este artigo planteia uma reflexão em torno à aplicação das teorias e métodos da antropologia em alguns aspectos práticos da administração que interessam aos negócios internacionais, tais como a cultura organizacional, a investigação de mercados e a dimensão intercultural que caracteriza a esta atividade no âmbito global. Se exploram algumas fontes bibliográficas e aportes de investigadores representativos que ilustram sobre o desenvolvimento profissional e académico e os debates que se geram ao interior desta subespecialidade da Antropologia na contemporaneidade. Se conclui que instrumentalizar o conhecimento cientí­fico sobre o comportamento cultural ao serviço do poder corporativo planteia problemas de ordem étic

De la imprenta a la Internet: instrumentos de universalización de la lengua inglesa

El siguiente ejercicio pretende abordar parte de la dinámica a través de la cual se abren paso en el horizonte cognitivo diversos “ingleses” o expresiones particulares de la misma lengua a lo largo y ancho del planeta, producto de coyunturas históricas particulares y bajo el influjo de la tecnología informática