Career: hybrid surfaces to control cell adhesion and function

Issued as final reportNational Science Foundation (U.S.

A decreasing step method for strongly oscillating stochastic models

We propose an algorithm for approximating the solution of a strongly oscillating SDE, that is, a system in which some ergodic state variables evolve quickly with respect to the other variables. The algorithm profits from homogenization results and consists of an Euler scheme for the slow scale variables coupled with a decreasing step estimator for the ergodic averages of the quick variables. We prove the strong convergence of the algorithm as well as a C.L.T. like limit result for the normalized error distribution. In addition, we propose an extrapolated version that has an asymptotically lower complexity and satisfies the same properties as the original version.Comment: Published in at http://dx.doi.org/10.1214/14-AAP1016 the Annals of Applied Probability (http://www.imstat.org/aap/) by the Institute of Mathematical Statistics (http://www.imstat.org

Un-Reduction of Systems of Second-Order Ordinary Differential Equations

In this paper we consider an alternative approach to "un-reduction". This is the process where one associates to a Lagrangian system on a manifold a dynamical system on a principal bundle over that manifold, in such a way that solutions project. We show that, when written in terms of second-order ordinary differential equations (SODEs), one may associate to the first system a (what we have called) "primary un-reduced SODE", and we explain how all other un-reduced SODEs relate to it. We give examples that show that the considered procedure exceeds the realm of Lagrangian systems and that relate our results to those in the literature

Reporting biases and survey results: evidence from European professional forecasters

Using data from the ECB's Survey of Professional Forecasters, we investigate the reporting practices of survey participants by comparing their point predictions and the mean/median/mode of their probability forecasts. We find that the individual point predictions, on average, tend to be biased towards favourable outcomes: they suggest too high growth and too low inflation rates. Most importantly, for each survey round, the aggregate survey results based on the average of the individual point predictions are also biased. These findings cast doubt on combined survey measures that average individual point predictions. Survey results based on probability forecasts are more reliable. JEL Classification: C42, E27, E47point estimates, subjective probability distributions, survey methods, Survey of Professional Forecasters (SPF)

La educación emocional como método para mejorar los problemas de conducta de los niños y niñas. Una experiencia llevada a cabo en República Dominicana

XXII Jornades de Foment de la Investigació de la Facultat de Ciències Humanes i Socials (Any 2017)Actualmente, la educación emocional ha ido cobrando importancia en las escuelas y se ha considerado que, para que la educación conlleve un desarrollo pleno e integral de la personalidad de los niños, es necesario que el desarrollo cognitivo y emocional se contemplen. En este sentido, la inteligencia emocional comprende un conjunto de habilidades como la identificación y expresión de emociones, las habilidades socioemocionales, la autonomía emocional y el autocontrol. Además, ayuda a tomar mejor las decisiones, a confiar en los demás, a mejorar la conducta y a desarrollar relaciones interpersonales satisfactorias. Por ello, debería iniciarse desde los primeros años de escolarización, y ser una práctica continuada a lo largo de la escolaridad. En el presente estudio se implementó un método de intervención en educación emocional en un aula ordinaria de 1.º de educación primaria (24 niños entre 6 y 8 años) de un colegio de República Dominicana, en la que se observaron graves problemas de conducta en gran parte del alumnado de la clase. La duración de la intervención fue de seis sesiones (una por semana), extraídas de una guía elaborada por las autoras donde se proponen recomendaciones y recursos para mejorar las competencias emocionales de los niños y niñas de edad escolar, siguiendo los hitos evolutivos del desarrollo emocional infantil típico, y estructuradas en sus distintos componentes. Con el fin de conocer la efectividad del método sobre la competencia emocional del alumnado, este fue evaluado con la aplicación Emocionatest antes y después de llevar a cabo la intervención. Los resultados del estudio mostraron que todos los niños y las niñas mejoraron sus competencias emocionales, aunque hubo diferencias entre los logros conseguidos. Se concluye sobre el valor de la educación emocional ante la prevención de los problemas de conducta, y se destaca la necesidad de potenciar su desarrollo desde el inicio de la escolarización

PWM Control of a Buck Converter with an Amorphous Core Coil

Pulse-width modulation is widely used to control electronic converters. One of the most topologies used for high DC voltage/low DC voltage conversion is the Buck converter. It is obtained as a second order system with a LC filter between the switching subsystem and the load. The use of a coil with an amorphous magnetic material core instead of air core lets design converters with smaller size. If high switching frequencies are used for obtaining high quality voltage output, the value of the auto inductance L is reduced throughout the time. Then, robust controllers are needed if the accuracy of the converter response must not be affected by auto inductance and load variations. This paper presents a robust controller for a Buck converter based on a state space feedback control system combined with an additional virtual space variable which minimizes the effects of the inductance and load variations when a not-toohigh switching frequency is applied. The system exhibits a null steady-state average error response for the entire range of parameter variations. Simulation results are presented

Isolated factorizations and their applications in simplicial affine semigroups

We introduce the concept of isolated factorizations of an element of a commutative monoid and study its properties. We give several bounds for the number of isolated factorizations of simplicial affine semigroups and numerical semigroups. We also generalize $\alpha$-rectangular numerical semigroups to the context of simplicial affine semigroups and study their isolated factorizations. As a consequence of our results, we characterize those complete intersection simplicial affine semigroups with only one Betti minimal element in several ways. Moreover, we define Betti sorted and Betti divisible simplicial affine semigroups and characterize them in terms of gluings and their minimal presentations. Finally, we determine all the Betti divisible numerical semigroups, which turn out to be those numerical semigroups that are free for any arrangement of their minimal generators