Quick minds don't blink: electrophysiological correlates of individual differences in attentional selection.

A well-established phenomenon in the study of attention is the attentional blink-a deficit in reporting the second of two targets when it occurs 200-500 msec after the first. Although the effect has been shown to be robust in a variety of task conditions, not every individual participant shows the effect. We measured electroencephalographic activity for "nonblinkers" and "blinkers" during execution of a task in which two letters had to be detected in an sequential stream of digit distractors. Nonblinkers showed an earlier P3 peak, suggesting that they are quicker to consolidate information than are blinkers. Differences in frontal selection positivity were also found, such that nonblinkers showed a larger difference between target and distractor activation than did blinkers. Nonblinkers seem to extract target information better than blinkers do, allowing them to reject distractors; more easily and leaving sufficient resources available to report both targets

Dopant-induced crossover from 1D to 3D charge transport in conjugated polymers

The interplay between inter- and intrachain charge transport in bulk polythiophene in the hopping regime has been clarified by studying the conductivity s as a function of frequency ¿/2p (up to 3 THz), temperature T, and doping level c. We present a model which quantitatively explains the observed crossover from quasi-one-dimensional transport to three-dimensional hopping conduction with increasing doping level. At high frequencies the conductivity is dominated by charge transport on one-dimensional conducting chains

Spatiotemporal Heterogeneity of κ-Carrageenan Gels Investigated via Single-Particle-Tracking Fluorescence Microscopy

Hydrogels made of the polysaccharide κ-carrageenan are widely used in the food and personal care industry as thickeners or gelling agents. These hydrogels feature dense regions embedded in a coarser bulk network, but the characteristic size and behavior of these regions have remained elusive. Here, we use single-particle-tracking fluorescence microscopy (sptFM) to quantitatively describe κ-carrageenan gels. Infusing fluorescent probes into fully gelated κ-carrageenan hydrogels resulted in two distinct diffusional behaviors. Obstructed self-diffusion of the probes revealed that the coarse network consists of κ-carrageenan strands with a typical diameter of 3.2 ± 0.3 nm leading to a nanoprobe diffusion coefficient of ∼1-5 × 10-12 m2/s. In the dense network regions, we found a fraction with a largely decreased diffusion coefficient of ∼1 × 10-13 m2/s. We also observed dynamic exchange between these states. The computation of spatial mobility maps from the diffusional data indicated that the dense network regions have a characteristic diameter of ∼1 μm and show mobility on the second-to-minute timescale. sptFM provides an unprecedented view of spatiotemporal heterogeneity of hydrogel networks, which we believe bears general relevance for understanding transport and release of both low- and high-molecular weight solutes.</p

Plurilingüismo: por qué ser personas plurilingües y cuándo iniciar el aprendizaje

Treball Final de Grau en Mestre o Mestra d'Educació Primària. Codi: MP1040. Curs acadèmic: 2016/2017Entendemos como plurilingüismo aquellas variedades lingüísticas que utiliza un mismo locutor, ya sea la lengua materna y todas aquellas adquiridas posteriormente. Tenemos al alcance la opción de enriquecernos con lenguas diferentes a la nuestra y esto se considera un aspecto muy importante para el acceso a las manifestaciones culturales. La lengua regula nuestro pensamiento y todas nuestras ideas apoyadas por bases lingüísticas. Además, como seres sociales contamos con la necesidad de relacionarnos y de comunicarnos, para hacernos hueco en el progreso continuo de la sociedad. Por esta misma razón, se deben tener en cuenta ciertos aspectos culturales, características personales de los individuos de una sociedad y a qué estratificación social pertenecen, para poder llevar a cabo una Competencia Comunicativa adecuada. La conciencia es cada vez mayor en cuanto a la función que desempeñan los idiomas en el desarrollo, la diversidad cultural y en el fortalecimiento de la cooperación y la conservación del patrimonio cultural. Siempre se ha considerado esencial el aprendizaje de idiomas desde edades tempranas para poder exprimir esos conocimientos de cara al futuro, pero, ¿qué impacto tiene el plurilingüismo y el aprendizaje de nuevas lenguas en edades adultas? El derecho a aprender a lo largo de toda la vida es cada vez más ratificado, no obstante, la educación de adultos se encuentra muy rezagada con respecto a los demás sectores de la enseñanza. A lo largo de este trabajo de investigación descubriremos las ventajas cognitivas que presenta el plurilingüismo en la Educación para Adultos así como la eficiencia y los beneficios a los cuales llevan

Robust Optimization of the Equity Momentum Strategy

Quadratic optimization for asset portfolios often leads to error maximization, with optimizers zooming in on large errors in the predicted inputs, that is, expected returns and risks. The consequence in most cases is a poor real-time performance. In this paper we show how to improve real-time performance of the popular equity momentum strategy with robust optimization in an empirical application involving 1500-2500 US stocks over the period 1963-2006. We also show that popular procedures like Bayes-Stein estimated expected returns, shrinking the covariance matrix and adding weight constraints fail in such a practical cas

Measurement of the complex dielectric constant down to helium temperatures. I. Reflection method from 1 MHz to 20 GHz using an open ended coaxial line

Metals in Catalysis, Biomimetics & Inorganic Material

The metallic state in disordered quasi-one-dimensional conductors

The unusual metallic state in conjugated polymers and single-walled carbon nanotubes is studied by dielectric spectroscopy (8--600 GHz). We have found an intriguing correlation between scattering time and plasma frequency. This relation excludes percolation models of the metallic state. Instead, the carrier dynamics can be understood in terms of the low density of delocalized states around the Fermi level, which arises from the competion between disorder-induced localization and interchain-interactions-induced delocalization.Comment: 4 pages including 4 figure

Measurement of the complex dielectric constant down to helium temperatures. II. Quasi-optical technique from 0.03 to 1 THz

Metals in Catalysis, Biomimetics & Inorganic Material