Ahlfors-Weill extensions for harmonic mappings

We provide two new formulas for quasiconformal extension to C‾ for harmonic mappings defined in the unit disk and having sufficiently small Schwarzian derivative. Both are generalizations of the Ahlfors-Weill extension for holomorphic functionsPID2019-106870GB-I00, PID2019-106093GB-I0

De retibus socialibus et legibus momenti

Online Social Networks (OSNs) are a cutting edge topic. Almost everybody --users, marketers, brands, companies, and researchers-- is approaching OSNs to better understand them and take advantage of their benefits. Maybe one of the key concepts underlying OSNs is that of influence which is highly related, although not entirely identical, to those of popularity and centrality. Influence is, according to Merriam-Webster, "the capacity of causing an effect in indirect or intangible ways". Hence, in the context of OSNs, it has been proposed to analyze the clicks received by promoted URLs in order to check for any positive correlation between the number of visits and different "influence" scores. Such an evaluation methodology is used in this paper to compare a number of those techniques with a new method firstly described here. That new method is a simple and rather elegant solution which tackles with influence in OSNs by applying a physical metaphor.Comment: Changes made for third revision: Brief description of the dataset employed added to Introduction. Minor changes to the description of preparation of the bit.ly datasets. Minor changes to the captions of Tables 1 and 3. Brief addition in the Conclusions section (future line of work added). Added references 16 and 18. Some typos and grammar polishe

Mejora del comportamiento dinámico de puentes de ferrocarril mediante reaccionamiento con amortiguadores fluido-viscosos

This research work is devoted to the problem of excessive vertical vibrations that short to medium-span railway bridges may experiment due to resonance phenomena. A new alternative based on externally increasing the overall damping of the structure by retrofitting the deck with fluid-viscous dampers is proposed in order to reduce detrimental levels of transverse acceleration to admissible ones. This solution could substitute a classical strengthening process or even the complete demolition and replacement of the deck in existing structures under new traffic requirements such as an increase in the speed of the line. A particular configuration of the retrofitting system is proposed which allows the transformation of the vertical oscillations that the deck experiments under the circulation of the railway vehicles into elongation rates of the devices, leading to energy dissipation and the subsequent reduction of the super-structure resonant response. The proposed system could be installed in the original structure and maintained without interfering with everyday traffic

On weighted compositions preserving the Carathéodory class

This is a post-peer-review, pre-copyedit version of an article published in Monatshefte für Mathematik. The final authenticated version is available online at: http://dx.doi.org/10.1007/s00605-017-1093-3We characterize in various ways the weighted composition transformations which preserve the class P of normalized analytic functions in the disk with positive real part. We analyze the meaning of the criteria obtained for various special cases of symbols and identify the fixed points of such transformationsArévalo, Martín, and Vukotić are supported by MTM2015-65792-P from MINECO and FEDER/EU and partially by the Thematic Research Network MTM2015-69323-REDT, MINECO, Spain. Hernández and Martín are supported by FONDECYT 1150284, Chile. Martín is also supported by Academy of Finland Grant 26800

Efecto de incluir en la dieta un suplemento de uvas pasas, alimento rico en polifenoles, sobre la función cognitiva en adultos mayores sanos. Ensayo clínico controlado y aleatorizado

Tesis por compendio de publicaciones.[ES] La ingesta moderada y regular de alimentos ricos en polifenoles proporciona beneficios cognitivos. Concretamente, la suplementación de flavanoles y estilbenos mejora la atención, la velocidad psicomotora, el recuerdo retardado y el reconocimiento de palabras. La acción conjunta de flavonoides mejora la memoria visual en pacientes sin deterioro cognitivo y la memoria de trabajo en pacientes con patología cognitiva. Las uvas pasas, una de las frutas secas que caracteriza a la dieta mediterránea, son una de las principales fuentes de polifenoles. El suplemento diario de 50 g de uvas pasas Moscatel Málaga durante 6 meses, en población mayor de 70 años, mejora la orientación, la capacidad visoespacial, el lenguaje, la puntuación global del MoCA, el recuerdo inmediato y el recuerdo retardado. Además, se observa una ligera mejoría en la calidad de vida y en las actividades funcionales y una disminución de la IL-1. No hay cambios significativos en la glucosa, el colesterol total, el colesterol HDL, el colesterol LDL ni los triglicéridos. Hasta donde sabemos, este es un estudio pionero que analiza el efecto de las uvas pasas, alimento rico en polifenoles, en una población que, debido a su edad avanzada, presenta mayor riesgo de desarrollar deterioro cognitivo. [EN] Moderate and regular intake of polyphenol-rich foods provides cognitive benefits. Specifically, supplementation of flavanols and stilbenes improves attention, psychomotor speed, delayed recall and word recognition. The combined action of flavonoids improves visual memory in patients without cognitive impairment and working memory in patients with cognitive pathology. Raisins, one of the dried fruits that characterize the Mediterranean diet, are one of the main sources of polyphenols. The daily supplementation of 50 g of Malaga Muscatel raisins during 6 months, in a population over 70 years old, improves orientation, visuospatial capacity, language, MoCA global score, immediate and delayed memory. In addition, a slight improvement in quality of life and functional activities and a decrease in IL-1 is observed. There are no significant changes in glucose, total cholesterol, HDL cholesterol, LDL cholesterol and triglycerides. To our knowledge this is a pioneering study that analyzes the effect of raisins, a food rich in polyphenols, in a population that, due to their advanced age, presents a higher risk of developing cognitive impairment

Colloidal stability of gadolinium-doped ceria powder in aqueous and non-aqueous media

In this work the colloidal behaviour of Ce0.9Gd0.1O2-δ powder in aqueous and non-aqueous media (ethanol) is studied. Commercial powder was characterised by particle size distribution, specific surface area measurements, X-ray diffraction and scanning electron microscopy. Diluted suspensions were characterised by particle size distribution and zeta potential, using dynamic light scattering and laser Doppler velocimetry principles, respectively. The solubility of the powder in water as a function of pH was analysed by inductively coupled plasma atomic emission spectrometry. Colloidal stability was studied as a function of pH, type and concentration of dispersants (polyacrylic-based deflocculant in water and a phosphate ester in ethanol). The time stability of the suspensions was analysed by multiple light scattering. The most stable suspension was obtained with a phosphate ester content of 2.0wt% in ethanol. Finally, preliminary coatings have been obtained by dip coating using concentrated suspensions, which could be accessible to industrial scale so that they can be used as interlayers in solid oxide fuel cells. © 2012 Elsevier Ltd.We would like to thank grants PSE-120000-2008-0040 and MAT2009-14324-C02-01, financed by the Spanish Government (Ministerio de Ciencia e Innovación) and Feder Program of the European Community, and PI/116, financed by the Aragón Government.Peer Reviewe

A robust wavelet-based approach for dominant frequency analysis of atrial fibrillation in body surface signals

This is an author-created, un-copyedited versíon of an article published in Physiological Measurement. IOP Publishing Ltd is not responsíble for any errors or omissíons in this versíon of the manuscript or any versíon derived from it. The Versíon of Record is available online at https://doi.org/10.1088/1361-6579/ab97c1.[EN] Objective: Atrial dominant frequency (DF) maps undergoing atrial fibrillation (AF) presented good spatial correlation with those obtained with the non-invasive body surface potential mapping (BSPM). In this study, a robust BSPM-DF calculation method based on wavelet analysis is proposed. Approach: Continuous wavelet transform along 40 scales in the pseudo-frequency range of 3¿30 Hz is performed in each BSPM signal using a Gaussian mother wavelet. DFs are estimated from the intervals between the peaks, representing the activation times, in the maximum energy scale. The results are compared with the traditionally widely applied Welch periodogram and the robustness was tested on different protocols: increasing levels of white Gaussian noise, artificial DF harmonics presence and reduction in the number of leads. A total of 11 AF simulations and 12 AF patients are considered in the analysis. For each patient, intracardiac electrograms were acquired in 15 locations from both atria. The accuracy of both methods was assessed by calculating the absolute errors of the highest DFBSPM (HDFBSPM) with respect to the atrial HDF, either simulated or intracardially measured, and assumed correct if ¿1 Hz. The spatial distribution of the errors between torso DFs and atrial HDFs were compared with atria driving mechanism locations. Torso HDF regions, defined as portions of the maps with |DF ¿ HDFBSPM| ¿ 0.5 Hz were identified and the percentage of the torso occuping these regions was compared between methods. The robustness of both methods to white Gaussian noise, ventricular influence and harmonics, and to lower spatial resolution BSPM lead layouts was analyzed: computer AF models (567 leads vs 256 leads down to 16 leads) and patient data (67 leads vs 32 and 16 leads). Main results: The proposed method allowed an improvement in non-invasive estimation of the atria HDF. For the models the median relative errors were 7.14% for the wavelet-based algorithm vs 60.00% for the Welch method; in patients, the errors were 10.03% vs 12.66%, respectively. The wavelet method outperformed the Welch approach in correct estimations of atrial HDFs in models (81.82% vs 45.45%, respectively) and patients (66.67% vs 41.67%). A low positive BSPM-DF map correlation was seen between the techniques (0.47 for models and 0.63 for patients), highlighting the overall differences in DF distributions. The wavelet-based algorithm was more robust to white Gaussian noise, residual ventricular activity and harmonics, and presented more consistent results in lead layouts with low spatial resolution. Significance: Estimation of atrial HDFs using BSPM is improved by the proposed wavelet-based algorithm, helping to increase the non-invasive diagnostic ability in AF.This study was supported in part by grants from Sao Paulo Research Foundation (2017/19775-3), Instituto de Salud Carlos III FEDER (Fondo Europeo de Desarrollo Regional PI17/01106) and Generalitat Valenciana Grants (AICO/2018/267).Marques, V.; Rodrigo Bort, M.; Guillem Sánchez, MS.; Salinet, J. (2020). A robust wavelet-based approach for dominant frequency analysis of atrial fibrillation in body surface signals. Physiological Measurement. 41(7):1-14. https://doi.org/10.1088/1361-6579/ab97c1S11441

Desarrollo y validación estructural de una escala para evaluar la regulación de la ira y la tristeza en situaciones interpersonales

The purpose of this research was to develop and validate a new instrument to assess the regulation of anger and sadness in interpersonal situations, covering a wide range of emotion regulation strategies. Two studies were carried out, both of them using purposively selected samples. In Study 1 we created a set ofitems based on previous studies of emotion regulation, applied a preliminary version of this scale to a pilot sample of undergraduate students (n = 400), and then selected, using exploratory factor analysis (EFA), the best 28 items to include in a brief version of the instrument, the Scale of Emotion Regulation in Interpersonal Situations (SERIS). In Study 2 we tested the resulting scale ina new sample of undergraduate students (n = 259) by means of confirmatory factor analysis. Study 2 validated the factor structure identified in the EFA. Results showed that the scale has adequate internal consistency and psychometric properties. The new scale also identifies the strategies that are most frequently used in the anger and sadness scenarios, showing differential patterns which are consistent with previous literature on emotion regulation. We discuss the limitations of the study and acknowledge that future studies addressing the scale’s convergent and discriminant validity are now required.El objetivo de este trabajo es desarrollar una escala para evaluar la regulación emocional de la ira y la tristeza en situaciones interpersonales y que incluya un amplio rango de estrategias de regulación. Se realizaron dos estudios, contando ambos con muestras seleccionadas de manera intencional. En el estudio 1, se construyó un banco de ítems a partir de la revisión de la literatura, se aplicó a una muestra de estudiantes universitarios (n = 400) y se seleccionaron, mediante análisis factorial exploratorio, los mejores 28 indicadores para conformaruna escala breve llamada Escala de Regulación Emocional en Situaciones Interpersonales (ERESI). En el estudio 2 se validó en una nueva muestra, compuesta también por estudiantes universitarios (n = 259), la estructura factorial de la escala desarrollada en el estudio 1, aplicando un análisis factorial confirmatorio. Los resultados validaron la estructura factorial extraída del estudio 1, y señalaron que el instrumento cuenta con adecuada consistencia interna y validez estructural. También se verificó que el instrumento permite identificarlas estrategias más aplicadas en las situaciones de ira y de tristeza, hallando patrones diferenciales para cada emoción, y consistentes con la literatura existente sobre regulación emocional. Se discutieron las limitaciones y la necesidad de continuar con estudios de validación convergente y discriminante