Paradojas de la memoria

Se pasa revista en el artículo a diferentes teorías sobre la naturaleza de la memoriay el recuerdo, descartándose su concepción tradicional como depósito o registro de experiencias pasadas. A la luz de algunos hallazgos de la moderna neurociencia se muestra, encambio, el carácter dinámico, multidimensional, constructivo y contextual que tiene toda rememoración. Por último se postula la permanencia e identidad del yo como condición necesaria de la memoria.

Differences in diet between the two largest breeding colonies of Audouin's gulls: the effects of fishery activities

We analysed and compared the diet of Audouin´s gulls Larus audouinii between their two largest breeding sites in the world: the Ebro Delta and the Chafarinas Islands (western Mediterranean). These two localities showed marked differences in the features of the commercial fishing fleet: in the Ebro Delta area a large fishing fleet produced large amounts of discards, while in the Chafarinas the fleet discarded smaller amounts of fish and marine invertebrates, due to the smaller number of vessels. It is also likely that the percentage of discards from total catches is also lower around the Chafarinas than at the Ebro Delta. We distinguished two types of fishing to compare diet compositions: diurnal (only trawling activity) and diurnal and nocturnal (trawling and purse-seine activity, respectively). We also differentiated regurgitates from young nestlings (up to 20 days old) and from older nestlings or adult birds. At the two localities, fish was the main food of Audouin´s gulls, with epipelagic prey (mainly clupeoids) being more important when both diurnal and nocturnal fisheries were operating. This confirms that epipelagic prey either caught actively by the gulls or linked to fisheries was particularly important in the feeding habits of Audouin´s gulls. Nevertheless, differences between the two colonies appear mainly when only trawlers operated: while at the Ebro Delta gulls showed higher consumption of benthic-mesopelagic prey (probably linked to a higher trawler discard availability), gulls from the Chafarinas Islands consumed higher biomass of epipelagic prey probably caught actively at night. When both fleets operated around the two colonies, the average biomass of prey in a regurgitate of younger chicks was significantly higher at the Ebro Delta than at Chafarinas, and the opposite trend was recorded for older nestlings and adults. Niche width was broader in Chafarinas than in the Ebro Delta for both age classes and for any fishing fleet schedule, suggesting again that the exploitation of discards was higher at the Ebro Delta than at the Chafarinas, where gulls showed a more varied diet. Despite the fact that availability of discards was probably higher at the Ebro Delta than at Chafarinas, the per capita availability was not so different at both localities due to the increasing seabird community population at the Ebro Delta, which ca. doubled that at Chafarinas in the last decade.

A comparison of rapid bioassessment protocols used in 2 regions with Mediterranean climates, the Iberian Peninsula and South Africa

Abstract. The ability of 2 Rapid Bioassessment Protocols (RBPs) to assess stream water quality was compared in 2 Mediterranean-climate regions. The most commonly used RBPs in South Africa (SAprotocol) and the Iberian Peninsula (IB-protocol) are both multihabitat, field-based methods that use macroinvertebrates. Both methods use preassigned sensitivity weightings to calculate metrics and biotic indices. The SA- and IB-protocols differ with respect to sampling equipment (mesh size: 1000 lm vs 250 300 lm, respectively), segregation of habitats (substrate vs flow-type), and sampling and sorting procedures (variable time and intensity). Sampling was undertaken at 6 sites in South Africa and 5 sites in the Iberian Peninsula. Forty-four and 51 macroinvertebrate families were recorded in South Africa and the Iberian Peninsula, respectively; 77.3% of South African families and 74.5% of Iberian Peninsula families were found using both protocols. Estimates of community similarity compared between the 2 protocols were .60% similar among sites in South Africa and .54% similar among sites in the Iberian Peninsula (BrayCurtis similarity), and no significant differences were found between protocols (Multiresponse Permutation Procedure). Ordination based on Non-metric Multidimensional Scaling grouped macroinvertebrate samples on the basis of site rather than protocol. Biotic indices generated with the 2 protocols at each site did not differ. Thus, both RBPs produced equivalent results, and both were able to distinguish between biotic communities (mountain streams vs foothills) and detect water-quality impairment, regardless of differences in sampling equipment, segregation of habitats, and sampling and sorting procedures. Our results indicate that sampling a single habitat may be sufficient for assessing water quality, but a multihabitat approach to sampling is recommended where intrinsic variability of macroinvertebrate assemblages is high (e.g., in undisturbed sites in regions with Mediterranean climates). The RBP of choice should depend on whether the objective is routine biomonitoring of water quality or autecological or faunistic studies.

Multivariate prediction

The problem of prediction is considered in a multidimensional setting. Extending an idea presented by Barndorff-Nielsen and Cox, a predictive density for a multivariate random variable of interest is proposed. This density has the form of an estimative density plus a correction term. It gives simultaneous prediction regions with coverage error of smaller asymptotic order than the estimative density. A simulation study is also presented showing the magnitude of the improvement with respect to the estimative method.

Stochastic delay equations with non-negativity constraints driven by fractional Brownian motion

In this note we prove an existence and uniqueness result for the solution of multidimensional stochastic delay differential equations with normal reflection. The equations are driven by a fractional Brownian motion with Hurst parameter H > 1/2. The stochastic integral with respect to the fractional Brownian motion is a pathwise Riemann¿Stieltjes integral.

On the relationship between connections and the asymptotic properties of predictive distributions

In a recent paper, Komaki studied the second-order asymptotic properties of predictive distributions, using the Kullback-Leibler divergence as a loss function. He showed that estimative distributions with asymptotically efficient estimators can be improved by predictive distributions that do not belong to the model. The model is assumed to be a multidimensional curved exponential family. In this paper we generalize the result assuming as a loss function any f divergence. A relationship arises between alpha connections and optimal predictive distributions. In particular, using an alpha divergence to measure the goodness of a predictive distribution, the optimal shift of the estimate distribution is related to alpha-covariant derivatives. The expression that we obtain for the asymptotic risk is also useful to study the higher-order asymptotic properties of an estimator, in the mentioned class of loss functions.

Large deviations for stochastic Volterra equations

This paper is devoted to prove a large-deviation principle for solutions to multidimensional stochastic Volterra equations.

¿Merece la pena coligarse? La formación de gobiernos minoritarios en España, 1977-1996

Este trabajo trata de explicar los motivos que han llevado a los partidos políticos españoles a optar, en los procesos de formación de gobierno en situaciones parlamentarias minoritarias celebrados desde 1977, por la formación de gobiernos minoritarios. Contrariamente a lo sostenido por las teorías formales de las coaliciones políticas, la solución al proceso de formación de gobierno en el caso español responde a los cálculos estratégicos de los partidos políticos implicados en el fenómeno coalicional. Como se argumentará, la formación de gobiernos minoritarios en España se configura como soluciones racionales desde una óptica metodológica multidimensional.

Estructura factorial de la versión reducida del 'Eysenck Personality Profiler'

El objetivo de este trabajo es analizar la estructura factorial de la versión reducida del Eysenck Personality Profiler (EPP-SF), un cuestionario recientemente elaborado por Eysenck, Wilson y Jackson (1996) que permite la evaluación de los rasgos primarios más importantes que constituyen cada una de las tres dimensiones básicas de personalidad. Los resultados derivados de la aplicación de la técnica de análisis factorial y escalamiento multidimensional a las puntuaciones del EPP-SF de una muestra española de 946 sujetos replican los datos obtenidos en la muestra inglesa. La estructura factorial de la escala perfila claramente una composición tripartita y evidencia un aceptable grado de homogeneidad entre los rasgos primarios que constituyen cada uno de los tres tipos básicos de personalidad. Si bien, el rasgo primario de impulsividad sigue presentado saturaciones importantes en más de una dimensión. Este resultado es interpretado en los términos aducidos por el propio Eysenck, y otros autores, sobre la naturaleza multifactorial de este atributo de personalidad. Hecho que viene a constatar la necesidad de realizar estudios centrados en el análisis de la supuesta unidimensionalidad de las escalas que constituyen el EPP-SF.

Family burden related to clinical and functional variables of people with intellectual disability with and without a mental disorder

Few studies have been found that to assess the factors that explain higher levels of familyburden in adults with intellectualdisability (ID) and intellectualdisability and mental disorders (ID-MD). The aims of this study were to assess familyburden in people with ID and ID-MD and to determine which sociodemographic, clinical and functionaldisabilityvariables account for familyburden. The sample is composed of pairs of 203 participants with disability and their caregivers, of which 33.5% are caregivers of people with ID and 66.5% of ID-MD. Assessments were performed using scales of clinical and functionaldisability as the following instruments: Weschler Adult Intelligence Scale-III (WAIS-III), Inventory for Client and Agency Planning (ICAP), Psychiatric Assessment Schedule for Adults with Development Disability (PAS-ADD checklist), Disability Assessment Schedule of the World Health Organization (WHO-DAS-II) and familyburden (Subjective and Objective FamilyBurden Inventory - SOFBI/ECFOS-II). People with ID-MD presented higher levels of functionaldisability than those with ID only. Higher levels of familyburden were related to higher functionaldisability in all the areas (p < 0.006-0.001), lower intelligence quotient (p < 0.001), diagnosis of ID-MD (p < 0.001) and presence of organic, affective, psychotic and behavioral disorders (p < 0.001). Stepwise multiple regression showed that behavioral problems, affective and psychotic disorder, disability in participation in society, disability in personal care and presence of ID-MD explained more than 61% of the variance in familyburden. An integrated approach using effective multidimensional interventions is essential for both people with ID and ID-MD and their caregivers in order to reduce familyburden.

Bioelectrochemical Treatment of Contaminated Groundwater

To remove these pollutants from groundwater, different technologies can be used. Currently, the Environmental Protection Agency (EPA) considers ion exchange, reverse osmosis and reverse electrodialysis to be effective methods for the decrease of their concentrations, below their limit in drinking water. These technologies have some drawbacks, such as low selectivity towards the target pollutant, high energy or chemicals requirements, and the generation of waste brine (pollutants are separated from water, not treated), which require an additional treatment. Bio Electro Chemical Systems (BES) could fill this niche

Symptom Check-List-90-R: fiabilidad, datos normativos y estructura factorial en estudiantes universitarios

El Symptom Checklist-90-R (SCL-90-R) es uno de los instrumentos más ampliamente utilizados en la medición de la sintomatología psicopatológica en población clínica y en población general. Ya que gran parte de la investigación en psicopatología se realiza con estudiantes universitarios, este estudio instrumental pretende proporcionar datos de referencia para esta población. Analizamos las propiedades psicométricas de esta escala en una muestra representativa de 1.277 estudiantes de la Universidad de Girona. Las dimensiones con puntuaciones más elevadas para el total de la muestra son Obsesividad-compulsividad, Depresión y Sensibilidad interpersonal. Los resultados muestran diferencias significativas entre hombres y mujeres. La fiabilidad de la escala resulta muy aceptable, con unos coeficientes de consistencia interna de las nueve dimensiones primarias y del GSI, que oscilan entre 0,69 y 0,97. El análisis de la estructura factorial y la fuerte interdependencia entre las escalas primarias cuestionan la multidimensionalidad del SCL-90-R y refuerzan la idea de que el instrumento proporciona una medida de distrés general, es decir, es un indicador unidimensional de malestar psicológico más que una medida de dimensiones psicopatológicas diferenciadas

Complexitat i fenomen (socio)linguístic

Intermediate phenomena of reality present particular characteristics of systemic self-organization, multilevel interrelations, recursivity, emergence of new «objects» with properties different from those of the elements that form them, and evolutionary dynamics, that probably need the formulation of new theoretical concepts and different paradigm principles. The sciences or perspectives of complexity, or the «complex» thinking, try to respond adequately to this complexity of reality. This approach adopts a multidimensional, integrated and dynamic view of reality: the world is made up of overlapping levels of different elements which produce new properties or new organizations at higher levels. If we conceive what we call languages as simple and decontextualized objects, we can understand some of the more mechanical aspects but we will ignore their conditions of existence, functionality, maintenance, variation, change and extinction.

Generic brands and product differentiation strategies

Generic or own brand products were initially only lesser expensive copies of the branded label alternative, but nowadays, pricing alone is not enough in order to survive in the Fast Moving Consumer Goods (FMCG) or Consumer Packaged Goods (CPG)markets. With this in mind manufacturers of generic brands have adapted to this rapidlygrowing niche by investing in design and marketing during the initial phase in order to be perceived as having a quality product comparable to that of the branded products. In addition, they have gone further ahead with a second phase and resorted to innovativeproduct differentiation strategies and even pure innovation in many cases. These strategies have granted generic brands constantly increasing market shares and a position of equals relative to national brands.Using previous analyses and case studies, this paper will provide conceptual and empirical evidence to explain the surprisingly fast growth and penetration of generic supermarket brands, which in their relatively short lifespan, have grown to rival the historical market leaders, the branded products. According to this analysis, the main conclusion is that the growth in generic brands can be explained not only by price competition, but also by the use of innovative product differentiation strategies.