Computational Design of Chemical Nanosensors: Metal Doped Carbon Nanotubes

We use computational screening to systematically investigate the use of transition metal doped carbon nanotubes for chemical gas sensing. For a set of relevant target molecules (CO, NH3, H2S) and the main components of air (N2, O2, H2O), we calculate the binding energy and change in conductance upon adsorption on a metal atom occupying a vacancy of a (6,6) carbon nanotube. Based on these descriptors, we identify the most promising dopant candidates for detection of a given target molecule. From the fractional coverage of the metal sites in thermal equilibrium with air, we estimate the change in the nanotube resistance per doping site as a function of the target molecule concentration assuming charge transport in the diffusive regime. Our analysis points to Ni-doped nanotubes as candidates for CO sensors working under typical atmospheric conditions

Phonon-induced entanglement dynamics of two donor-based charge quantum bits

The entanglement dynamics of a pair of donor-based charge qubits is obtained in analytical form. The disentanglement is induced by off resonant scattering of acoustical phonons in the semiconductor host. According to our results a rather unusual recovery of entanglement occurs that depends on the geometrical configuration of the qubits. In addition, for large times a non-vanishing stationary entanglement is predicted. For the cases of one and two initial excitations a simple kinetic interpretation allows for an adequate analysis of the observed dynamics. Our results also reveal a direct relation between the disentanglement rate and the inter-donor decoherence rates

Effects of Brain Gym® Exercises in Institutionalized Older Adults with Cognitive Impairment

Este estudio tuvo como objetivo comparar los efectos de un programa de ejercicios de Brain Gym® con un programa de gimnasia de mantenimiento en pacientes mayores institucionalizados con deterioro cognitivo. Veintinueve personas institucionalizadas con deterioro cognitivo participaron en dos programas, uno basado en ejercicios de Brain Gym® y otro de gimnasia de mantenimiento, durante 18 semanas. Se emplearon los test Mini-examen cognoscitivo, Fototest, Trail Making Test, Índice de Barthel y el Timed up and Go. No se encontraron mejoras significativas en las variables analizadas. Se observó una tendencia positiva, especialmente en el grupo de gimnasia de mantenimiento, en la función cognitiva global y salud física. En conclusión, los efectos de un programa de ejercicios de Brain Gym® en una muestra de personas mayores institucionalizadas con deterioro cognitivo fueron similares a los de un programa de gimnasia de mantenimiento, sin mejoras significativas de la función cognitiva o independencia funcionalThis study aimed at comparing the effects of a program based on Brain Gym® exercises against a fitness exercise program on the cognitive function and functional independence in institutionalized older adults with cognitive impairment. Twenty-nine institutionalized older adults with cognitive impairment took part either on a Brain Gym® based exercise program or on a fitness exercise program during eighteen weeks. The assessment measures used were the Mini-Examen Cognoscitivo, Fototest, Trail making test, Barthel Index and the Timed up and Go Test. None of the variables analysed improved significantly. A trend towards improvement, particularly in the fitness exercise group, in both cognitive status and functional independence was observed. In conclusion, the performance of a Brain Gym® exercise-based program had the same effects than taking part in a fitness exercise program, with no significant improvements on the cognitive function or functional independence, in a sample of institutionalized older adults with cognitive impairmen

Standardized age - Length key for east Atlantic and Mediterranean bluefin tuna based on otoliths readings.

This paper presents an age-length key (ALK) based on age estimates from otoliths following a recent standardized reading criterion. Sampling of Atlantic bluefin tuna (Thunnus thynnus) otoliths comes from the “Biological and genetic sampling and analysis" (GBYP) project and was complemented with some samples from the Spanish institute of Oceanography. Using 2010 to 2012 data improves length range and monthly sampling coverage. Variability in length at age from ALK seems acceptable and although it was developed from data pooled over three years, the bias is likely to be small. Final age was adjusted to account for the date of capture and the timing of bands formation throughout the year. Monthly formation of edge type, translucent or opaque, was inconclusive and did not allow establishing an annual formation pattern. The confidence interval of the von Bertalanffy growth model curve fitted to ALK data included currently adopted growth function for eastern bluefin stock and western stock function up to age 8. From age 9, this last western function predicts slightly older ages than the present ALK growth model.Postprint0,000

Self-healing of dense asphalt concrete by two different approaches: electromagnetic induction and infrared radiation

Self-healing of cracks in asphalt mixtures is a phenomenon that can be accelerated by reducing the viscosity of bitumen as it increases the capillarity flow through the cracks. One method to achieve this is by increasing temperature, which also produces a thermal expansion that contributes to the circulation of the bitumen through cracks. In the present paper, the healing performance of asphalt mixture heated using infrared heating to simulate the natural solar radiation, and induction heating, a new method to increase the temperature of asphalt pavements, were compared in terms of time and healing temperature. Healing was defined as the relationship between the 3-point bending strength of an asphalt beam before and after healing. The results show that both methods reach similar and satisfactory healing ratios at around 90 %. However, induction heating is more energy efficient because the effect is concentrated on the binder, instead of heating the whole mix. This can be translated into much shorter heating times to reach the same healing level. Finally, an optimum radiation energy was found, after which higher amounts of infrared radiation damage the properties of the healed material

Impurity Effects in Two-Electron Coupled Quantum Dots: Entanglement Modulation

We present a detailed analysis of the electronic and optical properties of two-electron quantum dots with a two-dimensional Gaussian confinement potential. We study the effects of Coulomb impurities and the possibility of manipulate the entanglement of the electrons by controlling the confinement potential parameters. The degree of entanglement becomes highly modulated by both the location and charge screening of the impurity atom, resulting two regimes: one of low entanglement and other of high entanglement, with both of them mainly determined by the magnitude of the charge. It is shown that the magnitude of the oscillator strength of the system could provide an indication of the presence and characteristics of impurities that could largely influence the degree of entanglement of the system.Comment: Regular Article (Journal of Physics B, in press), 9 pages, 10 figure

Descripción de los parámetros fonético-acústico y autopercepción vocal de telefonistas en la región Metropolitana de Chile

Tesis (Fonoaudiología)Los callcenters son un espacio laboral que se ha desarrollado ampliamente en el presente siglo y con ello el rubro de los telefonistas se encuentra en aumento. Sin embargo, la rapidez con que éstos se han instaurado dentro de nuestra sociedad, no ha permitido una valoración adecuada de las posibles consecuencias que tiene el uso de la voz durante las horas que comprende una jornada laboral. El presente estudio, consistió en describir y establecer una relación de los parámetros fonético-acústicos (frecuencia fundamental, Jitter, Shimmer y relación ruido/armónico) y autopercepción vocal en telefonistas de la Región Metropolitana de Chile, utilizando los instrumentos Multidimensional Voice Program (MDVP) e Índice de Incapacidad Vocal (VHI). La muestra de este estudio estuvo compuesta por 56 sujetos, de los cuales 14 eran hombres y las 42 restantes, mujeres, que se desempeñan al año 2013 como telefonistas dentro de uno de los cuatro callcenters seleccionados y que pertenecen a la Región Metropolitana de Chile. En cuanto a los resultados del MDVP, se pudo evidenciar que la utilización de esta herramienta fue eficiente en la entrega de los resultados. Respecto de las diferencias encontradas entre el MDVP y VHI como instrumentos de evaluación simultáneos, se demuestran que todavía ningún parámetro objetivo puede considerarse como factor pronóstico definitivo en la evaluación de los pacientes y que las sensaciones acerca de su problema vocal no pueden valorarse mediante medidas objetivas.Se evidencia la alteración vocal objetiva presente en el 41 % de la muestra y se observa una tendencia a presentar primordialmente solo un parámetro alterado, siendo principalmente Jitter o FO, lo que se registra en un 30% aproximadamente. Respecto a la autopercepción vocal, se obtuvo que el 89% de ellos distinguen una alteración leve en su voz y tan solo un 10% alude a un daño moderado. No se evidenció correlación significativa entre los parámetros fonéticoacústicos y la autopercepción vocal de los telefonistas de la Región Metropolitana.The callcenters are a working place with a significant development during the present century and with it, the function of the telephone operators is growing. However, the fast introduction of them into our society, hasn't allow a proper appreciation of the impact that have the use of the voice during the hours of a working day. The present study consist in the description and stablish a relationship between the phonetic-acoustic parameters (fundamental frequency, Jitter, Shimmer and the relationship noise/harmonic) and the vocal self-perception on telephone operators of Chile's RegiónMetropolitana, using the Multidimensional Voice Program (MDVP) and the Vocal Handicap lndex (VHI) instruments. The sampling of this study was composed by 56 subjects, of which 14 were men and the 42 remaining were women, who work at the year 2013 as telephone operators inside tour selected callcenters of Chile's RegiónMetropolitana. As soon as the results of the MDVP, it was evidenced that the utilization of this tool was efficient at the results development. Respect the differences found between the MDVP and the VHI as evaluation instruments, evidence that no objective parameter can be considerad as an optimal prognostic factor on the patient evaluations and their feelings about own vocal problems can't be assessed by objective measures. Is Evidenced the objective vocal disturbance present in the 41 % of the sample and is observad a tendency to present primarily only one altered parameter, being mainly Jitter or FO, which is registered by a 30%, approximately. Respect the vocal self perception, was obtained that the 89% of them distinguishes a slight alteration on their voice and only the 10% a moderated harm. lt not was evidenced a significativa correlation between the phonetic-acoustic parameters and the vocal self-perception of telephone operators of the RegiónMetropolitana