A multivariate generalized independent factor GARCH model with an application to financial stock returns

We propose a new multivariate factor GARCH model, the GICA-GARCH model , where the data are assumed to be generated by a set of independent components (ICs). This model applies independent component analysis (ICA) to search the conditionally heteroskedastic latent factors. We will use two ICA approaches to estimate the ICs. The first one estimates the components maximizing their non-gaussianity, and the second one exploits the temporal structure of the data. After estimating the ICs, we fit an univariate GARCH model to the volatility of each IC. Thus, the GICA-GARCH reduces the complexity to estimate a multivariate GARCH model by transforming it into a small number of univariate volatility models. We report some simulation experiments to show the ability of ICA to discover leading factors in a multivariate vector of financial data. An empirical application to the Madrid stock market will be presented, where we compare the forecasting accuracy of the GICA-GARCH model versus the orthogonal GARCH one

Bárbara Kruger: análisis sobre el activismo de su obra fotográfica

El propósito del presente trabajo es realizar un análisis sobre la controvertida obra fotográfica de la “artivista”1 estadounidense Bárbara Kruger, mediante la previa revisión literaria de aspectos antropológicos y de ámbito fotográficos propios del periodo posmoderno, relativos ambos, a las construcciones sociales que giran alrededor de la figura femenina y que la autora proyecta en su creación artística. El análisis antropológico muestra la influencia ejercida desde este campo en la configuración del concepto de su obra fotográfica, exportando las teorías planteadas en torno a las edificaciones de identidades sociales y los roles atribuidos a la mujer, persistentes en la actualidad debido al influjo mediático. De otro lado, los postulados posmodernos acerca de la inclusión de la práctica fotográfica dentro de las artes visuales, tienen su raíz en el alejamiento de ella respecto a los supuestos que establece la concepción artística de lo clásico. Kruger se inspira en esta actitud rupturista y se embarca en la elaboración de una obra cuyas claves son la 1) los fundamentos y procesos de la institución artística, 2) el carácter performativo, 3) el giro minimalista, 4) la experiencia estética como discontinuidad y 5) la atribución simbólica de la imagen.The purpose of the present work is to analyze the controversial photographic work of the American "artivista" Barbara Kruger, through the previous literary revision of anthropological and photographic aspects typical of the postmodern period, both related to the social constructions that revolve around Of the female figure and that the author projects in her artistic creation. The anthropological analysis shows the influence exerted from this field in the configuration of the concept of her photographic work, exporting these theories raised around the constructions of social identities and the roles attributed to women and that persist today due to media influence. On the other hand, the postmodern postulates about the inclusion of the photographic practice within the visual arts have their root in the distance of this with respect to the assumptions that establish the artistic conception of the classic. Kruger drinks of this break-up attitude and embarks on the elaboration of a work whose keys are the 1) the foundations and processes of the artistic institution, 2) the performative character, 3) the minimalist twist, 4) the aesthetic experience as discontinuity and 5) the symbolic attribution of the image.Universidad de Sevilla. Grado en Periodism

The memory of the past as mechanism of authority in the Cistercian castilian nunneries during the Late Middle Ages and Modern Age: Materiality and written discurse

Durante la Baja Edad Media y la Edad Moderna algunos monasterios del Císter femenino recurrieron a su etapa plenomedieval para legitimar su posición en momentos en los que su autoridad estaba siendo cuestionada por instituciones eclesiásticas y laicas, tratando de lograr una mayor cohesión interna sobre la base de su memoria. Estudiaremos esta realidad a través de los ejemplos de San Andrés de Arroyo, Santa María de Cañas, Santa María de Vileña y San Vicente de SegoviaDuring the Late Middle Ages and the Modern Age some Cistercian nunneries appealed to their Medieval period to legitimize their position when their authority was being questioned by ecclesiastical and secular institutions, so they could achieve greater internal cohesion arround their memory. We will study this fact through the examples of San Andrés de Arroyo, Santa María de Cañas, Santa María de Vileña and San Vicente de Segovi

Spatial Data Infrastructures as an Education Resource in Secondary Education in Spain and Argentina

Since the early 90s Spatial Data Infrastructures (SDI’s) have attracted considerable attention from governments, private sector, academic organizations, etc. But, above all, the advance of Information and Communication Technology (ICT) has contributed to add new perspectives to the world of SDI’s, thereby facilitating the access and exchange of Geographic Information at different levels, by means of its standardization and interoperability. Latin-American countries stand at different development levels with regard to the implementation of their SDI’s, both at national level and at local or regional government levels. Considering the growth perspectives of SDI’s, it is necessary to contribute to a wider diffusion of their potential and use in different environments, both public and private. In this context the education environment appears as an area where action is needed. Taking into account that current education should bring students closer to the new ICT tools, SDI´s appear to be a highly valuable education resource in order to deal with Geographic Information related contents in the context of secondary education. In order to consider this possibility, an assessment is needed of the students’ academic competence and the basic common contents of the curriculum, so that the subjects where SDI’s are to be used as an educational resource can be identified. In order to build appropriate foundations on which to develop a future proposal in which SDI´s are considered as an education resource to deal with Geographic Information related contents, a study has been carried out of the secondary education in 2 countries that show great differences in SDI development: Spain and Argentina

Las Infraestructuras de Datos Espaciales como un recurso educativo TIC en la Educación Secundaria Obligatoria de España

han recibido una considerable atención por parte de los gobiernos, el sector privado, las organizaciones académicas y otros. El avance de las Tecnologías de la Información y de las Comunicaciones (TIC) ha contribuido a sumar nuevas perspectivas al mundo de las IDE, posibilitando el acceso e intercambio a diferentes niveles de la Información Geográfica, mediante su estandarización e interoperabilidad de servicios. Considerando las perspectivas de crecimiento de las IDE, parece necesario contribuir a una mayor difusión de sus potencialidades y uso en distintos ámbitos, tanto públicos como privados. En este contexto el ámbito educativo se presenta como un espacio sobre el que se debe actuar. Tomando como referencia la especial atención que se le concede a la utilización de las TIC en los distintos niveles educativos, el presente trabajo expone las posibilidades que ofrecen la utilización de las Infraestructuras de Datos Espaciales (IDE) como un recurso educativo TIC en el contexto de la Educación Secundaria Obligatoria (ESO) de España

A multivariate generalized independent factor GARCH model with an application to financial stock returns

We propose a new multivariate factor GARCH model, the GICA-GARCH model , where the data are assumed to be generated by a set of independent components (ICs). This model applies independent component analysis (ICA) to search the conditionally heteroskedastic latent factors. We will use two ICA approaches to estimate the ICs. The first one estimates the components maximizing their non-gaussianity, and the second one exploits the temporal structure of the data. After estimating the ICs, we fit an univariate GARCH model to the volatility of each IC. Thus, the GICA-GARCH reduces the complexity to estimate a multivariate GARCH model by transforming it into a small number of univariate volatility models. We report some simulation experiments to show the ability of ICA to discover leading factors in a multivariate vector of financial data. An empirical application to the Madrid stock market will be presented, where we compare the forecasting accuracy of the GICA-GARCH model versus the orthogonal GARCH one.ICA, Multivariate GARCH, Factor models, Forecasting volatility

Exploring ICA for time series decomposition

In this paper, we apply independent component analysis (ICA) for prediction and signal extraction in multivariate time series data. We compare the performance of three different ICA procedures, JADE, SOBI, and FOTBI that estimate the components exploiting either the non-Gaussianity, or the temporal structure of the data, or combining both, non-Gaussianity as well as temporal dependence. Some Monte Carlo simulation experiments are carried out to investigate the performance of these algorithms in order to extract components such as trend, cycle, and seasonal components. Moreover, we empirically test the performance of those three ICA procedures on capturing the dynamic relationships among the industrial production index (IPI) time series of four European countries. We also compare the accuracy of the IPI time series forecasts using a few JADE, SOBI, and FOTBI components, at different time horizons. According to the results, FOTBI seems to be a good starting point for automatic time series signal extraction procedures, and it also provides quite accurate forecasts for the IPIs.ICA, Signal extraction, Multivariate time series, Forecasting

Análisis de la producción científica sobre tratamientos en drogodependencias en el quinquenio 2007-2011

En este artículo se realiza un análisis bibliométrico de la producción científica en el periodo de tiempo del 2007 al 2011. Para ello, se lleva a cabo una búsqueda en ISI y Scopus con términos relacionados tanto con el uso y abuso de drogas, como de tratamientos, terapias y programas de drogodependencias; además de excluir aquellos términos que hacen referencia a la patología dual y a la experimentación animal. Con un total de 670 artículos, se realiza manualmente una normalización de autores e instituciones y un análisis de los datos en la base de datos con el programa Microsoft Access. Los resultados muestran que las autoras más productivas son Petry, Nacy M. y Carrol, Kathleen M., y las instituciones más relevantes son La Universidad de Connecticut, la Universidad de Vermont y la Universidad de Yale y todas de Estados Unidos, resultando éste como el país más productivo (tabla 3). Se analiza la productividad relativa de las revistas de mayor relevancia. Se ha realizado un ratio con el PIB de cada país comparando la productividad científica por mil millones de dólares (tabla 7) y otro ratio con el censo poblacional comparado con la productividad científica (tabla 8). El país con el ratio más alto es Islandia. Además, se destacan las terapias más importantes resultando la cognitivo conductual la corriente más utilizada (gráfica 2).A bibliometric review of the scientific production about treating drug addiction during the 2007-2011 timeframe was done in this article. In order to do that, words related to drug use and abuse, as well as treatment, therapy and programs aimed at drug addicts were searched in ISI and Scopus. In addition, any terms that referred to dual pathology and animal experimentation were excluded. With a total of 670 articles, a manual normalization of authors and institutions was made, analyzing the data using Microsoft Access. The results show the most productive authors are Petry, Nacy M. and Carrol,Kathleen M., while the most relevant institutions are the University of Conneticut, the Universit of Vermont, the University of Yale, and many others in the United States, which is the most productive country (table 3). The relative productivity of the most relevant journals was analyzed. The relation between relevant scientific production and GDP in millions of dollars (table 7), and the relation between production and population for each country were also studied. The country with highest ratios is Iceland. In addition, The most relevant therapies were highlighted. The cognitive behavior therapy was the most used (graph 2)

Interactions between climate and nutrient cycles on forest response to global change: the role of mixed forests

Forest ecosystems are undergoing unprecedented changes in environmental conditions due to global change impacts. Modification of global biogeochemical cycles of carbon and nitrogen, and the subsequent climate change are affecting forest functions at different scales, from physiology and growth of individual trees to cycling of nutrients. This review summarizes the present knowledge regarding the impact of global change on forest functioning not only with respect to climate change, which is the focus of most studies, but also the influence of altered nitrogen cycle and the interactions among them. The carbon dioxide (CO2) fertilization effect on tree growth is expected to be constrained by nutrient imbalances resulting from highNdeposition rates and the counteractive effect of increasing water deficit, which interact in a complex way. At the community level, responses to global change are modified by species interactions that may lead to competition for resources and/or relaxation due to facilitation and resource partitioning processes. Thus, some species mixtures can be more resistant to drought than their respective pure forests, albeit it depends on environmental conditions and species' functional traits. Climate change and nitrogen deposition have additional impacts on litterfall dynamics, and subsequent decomposition and nutrient mineralization processes. Elemental ratios (i.e., stoichiometry) are associated with important ecosystem traits, including trees' adaptability to stress or decomposition rates. As stoichiometry of different ecosystem components are also influenced by global change, nutrient cycling in forests will be altered too. Therefore, a re-assessment of traditional forest management is needed in order to cope with global change. Proposed silvicultural systems emphasize the key role of diversity to assure multiple ecosystem services, and special attention has been paid to mixed-species forests. Finally, a summary of the patterns and underlying mechanisms governing the relationships between diversity and different ecosystems functions, such as productivity and stability, is provided.E.G.A. was funded by the TIMENUTRIENT project (ref. AGL2016-76463-P) granted by the Spanish Ministry of Economy and Competitiveness