The chemical composition of carbon stars: The R-type stars

The aim of this work is to shed some light on the problem of the formation of carbon stars of R-type from a detailed study of their chemical composition. We use high-resolution and high signal-to-noise optical spectra of 23 R-type stars selected from the Hipparcos catalogue. The chemical analysis is made using spectral synthesis in LTE and state-of-the-art carbon-rich spherical model atmospheres. We derive their CNO content (including the carbon isotopic ratio), average metallicity, lithium, and light (Sr, Y, Zr) and heavy (Ba, La, Nd, Sm) s-element abundances. The observed properties of the stars (galactic distribution, kinematics, binarity, photometry and luminosity) are also discussed. Our analysis shows that late-R stars are carbon stars with identical chemical and observational characteristics than the normal (N-type) AGB carbon stars. We confirm the results of the sole previous abundance analysis of early-R stars by Dominy (1984, ApJS, 55, 27), namely: they are carbon stars with near solar metallicity showing enhanced nitrogen, low carbon isotopic ratios and no s-element enhancements. In addition, we have found that early-R stars have Li abundances larger than expected for post RGB tip giants. We also find that a significant number (aprox. 40 %) of the early-R stars in our sample are wrongly classified, being probably classical CH stars and normal K giants. In consequence, we suggest that the number of true R stars is considerably lower than previously believed. We briefly discuss the different scenarios proposed for the formation of early-R stars. The mixing of carbon during an anomalous He-flash is favoured, although no physical mechanism able to trigger that mixing has been found yet. The origin of these stars still remains a mystery.Comment: 15 pages, 8 figures, accepted for publication in Astronomy and Astrophysic

An investigation of control strategies on gearbox damage

The impact of control on structural elements such as tower and blades have been thoroughly researched and the validity of analysis methods based on aeroelastic simulations is widely accepted. The implications on gearbox wear for various control strategies is less studied. Using RomaxDesigner for gearbox analysis, MLS and Romax have carried out an investigation where the impact of different control strategies on wear is assessed. The best measures accounting for gearbox damage are described and the different control strategies and their impact on the gearbox are detailed

Influencia de las estrategias cognitivas de regulación emocional sobre la ansiedad y depresión en universitarios: análisis preliminar

Resumen Objetivo Determinar la influencia de las estrategias cognitivas de regulación emocional sobre la ansiedad y depresión en universitarios. Materiales y métodos Esta investigación se llevó a cabo con una muestra de 127 individuos (69.3% mujeres) entre 18 y 57 años. Fue implementado un análisis de regresión múltiple para ansiedad (GAD-2) y depresión (PHQ-2), con las subescalas del CERQ como predictores. Resultados En ambos casos, los predictores explican una variabilidad elevada de los criterios (R2 > 50%). Las estrategias cognitivas de Rumiación y Catastrofización predicen en mayor grado la ansiedad; y Catastrofizacion y Reinterpretación Positiva predicen positiva y negativamente, de forma respectiva, la depresión. Conclusiones La influencia de las estrategias cognitivas de regulación emocional sobre la ansiedad y depresión es significativa. Se discuten las consecuencias prácticas y las limitaciones del estudio

A Modelling Approach: Effects of Exuded Organic Acids and Exogenous Chelating Ligands on Bioavailability and Uptake of Metals by Radishes (Raphanus sativus) Grown in Hydroponics.

Metal contamination of soil can be reduced by adding chelators to improve the efficiency of metal uptake in phytoremediation, but optimal concentrations and types of chelators have not been determined. A geochemical model (Visual MINTEQ3.1) was used to estimate the effects of four chelators on the solubility of four metals in hydroponic solution. The model showed that no iron was soluble in the absence of a chelator, while the solubilities of cadmium, copper and zinc were high with or without chelators. Despite low iron uptake in all treatments, symptoms of iron-deficiency were not visible. High concentrations of exuded organic acids in solution had negligible effects on metal solubility because few metal-organic acid complexes formed. The amounts of metals taken up by radish (Raphanus sativus L.) varied with the type of chelator provided. EDTA and DTPA maximized cadmium and zinc uptake, respectively

Afrontamiento ante la ansiedad pre-examen y autoeficacia académica en estudiantes de ciencias de la salud

ResumenObjetivoAnalizar la relación entre las estrategias de afrontamiento ante la situación pre-examen y la autoeficacia académica en una muestra de estudiantes de ciencias de la salud.MétodoSe evaluó una muestra de 208 estudiantes (55,8% mujeres) de entre 16 y 35años (M=20,37; DE=3,155). Se usaron la Escala de afrontamiento ante la ansiedad e incertidumbre pre-examen y la Escala de autoeficacia percibida específica de situaciones académicas. La fiabilidad por consistencia fue calculada para cada subescala a través del coeficiente alfa. La relación entre variables fue analizada a través del coeficiente de correlación de Pearson.ResultadosSe hallaron correlaciones estadísticamente significativas entre la autoeficacia académica percibida y las estrategias Orientación a la tarea y Evitación, pero cercanas a cero con las estrategias de Búsqueda de apoyo.ConclusiónLas relaciones encontradas indican que las personas con mayor autoeficacia académica tienden a usar estrategias más vinculadas con el control de la situación previa al examen, que las destinadas a evitar o buscar apoyo.AbstractObjectiveThe aim of the study was to analyse the relationship between coping with pre-examination anxiety and academic self-efficacy in health sciences college students.MethodThe study was conducted on a sample of 208 students (55.8% women) between ages 16 and 35years old. The Coping with Pre-Exam Anxiety and Uncertainty and the Academic Situations Specific Perceived Self-efficacy Scale was used. The reliability was assessed by the coefficient alpha. The relationship between variables was assess using the Pearson correlation.ResultsA significant relationship was found between perceived academic self-efficacy, and two strategies: Task-Oriented and Avoidance; but near to zero with seek-support strategy.ConclusionThe relationships found show that people with higher academic self-efficacy tend to use more strategies related to control of the situation before the examination, than those related to avoid or seek-support

Processing ambiguous fault signals with three models of feedforward neural networks

In the industrial technological field, running equipment or processes usually is monitored through automatic diagnosis systems. Within several Technologies for implementing such systems, the artificial neuronal networks are the most successful and widely spread. The data signals coming from the equipments or processes under supervision are interpreted by the neuronal networks so as to diagnose the presence of any fault. In this work three models of artificial neural networks and two methods of training are analyzed so as to establish, based on real experiences, the best combination of the neuronal model and the training method for recognizing in an efficient way the ambiguous patterns of faults.Presentado en el I Workshop Procesamiento de señales y Sistemas de Tiempo Real (WPSTR)Red de Universidades con Carreras en Informática (RedUNCI

El poder de prevision para la propia incapacidad

49 p."El Poder de Previsión para la Propia Incapacidad", es una institución que habilita a quien prevé su incapacidad futura, estipular con el agente instrucciones que cobrarán vigencia cuando cayere en incapacidad, física o mental, total o parcial. Nuestra legislación constitucional, civil y penal, no la considera; sin embargo, tiene cabida en los derechos patrirrioniales, y no en los sujetivos debido a la problemática moral que implica y por tipificar conductas delictuosas, como la eutanasia y el auxilio al suicidio. Por lo anteriormente expuesto, el memorista ve lejana la posibilidad que se legisle en Chile sobre ésta materia, y si ocurriese, sería imprescindible un adecuado control judicial, y el efectivo cumplimiento de las solemnidades propias de la escritura pública celebrada ante el competente Notario Público, a fin de asegurar la correcta ejecución de las instrucciones otorgadas

Quantifying image distortion based on Gabor filter bank and multiple regression analysis

Image quality assessment is indispensable for image-based applications. The approaches towards image quality assessment fall into two main categories: subjective and objective methods. Subjective assessment has been widely used. However, careful subjective assessments are experimentally difficult and lengthy, and the results obtained may vary depending on the test conditions. On the other hand, objective image quality assessment would not only alleviate the difficulties described above but would also help to expand the application field. Therefore, several works have been developed for quantifying the distortion presented on a image achieving goodness of fit between subjective and objective scores up to 92%. Nevertheless, current methodologies are designed assuming that the nature of the distortion is known. Generally, this is a limiting assumption for practical applications, since in a majority of cases the distortions in the image are unknown. Therefore, we believe that the current methods of image quality assessment should be adapted in order to identify and quantify the distortion of images at the same time. That combination can improve processes such as enhancement, restoration, compression, transmission, among others. We present an approach based on the power of the experimental design and the joint localization of the Gabor filters for studying the influence of the spatial/frequencies on image quality assessment. Therefore, we achieve a correct identification and quantification of the distortion affecting images. This method provides accurate scores and differentiability between distortions

Estimación de elasticidades de sustitución de armington: una aplicación para España (1995-2018) = Estimation of armington elasticities of substitution: an implementation for spain (1995-2018)

La elasticidad de Armington es un concepto ampliamente extendido en teoría económica internacional, y presenta un papel clave en lo modelos de equilibrio general computable. Este trabajo presenta dos enfoques diferenciados. En primer lugar, un enfoque teórico a través del cual se lleva a cabo una revisión bibliográfica con la intención de derivar la forma de la elasticidad de Armington. En segundo lugar, un enfoque practico, en el que se utilizaran series temporales para poder estimar el valor de la elasticidad de Armington. Combinando ambos enfoques, el objetivo de este trabajo será estimar dicha elasticidad para el sector industrial y el sector de servicios en España entre los años 1995 y 2018