Rational functions associated with double infinite sequences of complex numbers

AbstractLet {μk}−∞+∞ be a given double infinite sequence of complex numbers. By defining a linear functional on the space of the Laurent polynomials, certain rational functions are first constructed and some algebraic properties studied.The hermitian case, i.e. μ−k = μk, k ∈ Z is separately considered and it is shown how the theory of polynomials orthogonal on the unit circle can be used in order to prove geometric convergence for sequences such as these rational functions

La Problematica Ambiental y los Centros de Desarrolo Academico

This article is presented as the second part of the one published on Issue 10 of Poliantea: Environmental Review and Management Problem. Here, we review specific environmental management undertaken by the universities since its inception in 1950, along with its commitments and partnerships that were consolidated over time. The study shows conceptions and events of environmental culture in the different institutions of higher education, its interest in the processes of training in the subject and social responsibility as centers of generation of solutions to the problems of global environmental degradation. Finally, it includes a picture sequence of initiatives and events organized by universities since the fifties. It aims to show the importance of the various actions and accomplishments of the different university communities regarding environmental issues

Realization of an all-optical zero to π cross-phase modulation jump

We report on the experimental demonstration of an all-optical π cross-phase modulation jump. By performing a preselection, an optically induced unitary transformation, and then a postselection on the polarization degree of freedom, the phase of the output beam acquires either a zero or π phase shift (with no other possible values). The postselection results in optical loss in the output beam. An input state may be chosen near the resulting phase singularity, yielding a pi phase shift even for weak interaction strengths. The scheme is experimentally demonstrated using a coherently prepared dark state in a warm atomic cesium vapor

Exact Random Walk Distributions using Noncommutative Geometry

Using the results obtained by the non commutative geometry techniques applied to the Harper equation, we derive the areas distribution of random walks of length $N$ on a two-dimensional square lattice for large $N$, taking into account finite size contributions.Comment: Latex, 3 pages, 1 figure, to be published in J. Phys. A : Math. Ge

Probalandia, un escenario de juegos de azar para la enseñanza de las técnicas de conteo y el concepto básico de probabilidad

Se asume la teoría de situaciones didácticas como forma de orientar el proceso de aprendizaje de los escolares, la cual plantea que no es posible transmitir el saber al estudiante de forma directa sino que es necesario recrear una micro-cultura del hacer matemático para que los alumnos requieran solucionar y adaptarse a problemáticas de un medio. Por ello se presenta una experiencia que consistió en recrear un escenario llamado Probalandia (centro de entretenimiento famoso por ejecutar cuatro juegos de azar que eran justos, pero que perdió credibilidad cuando se murmuró que ya no lo eran) en el cual estudiantes de 11° encontraron juegos justos e injustos y con ello aprendieron técnicas de conteo y el concepto básico de probabilidad

Entropic Barriers, Frustration and Order: Basic Ingredients in Protein Folding

We solve a model that takes into account entropic barriers, frustration, and the organization of a protein-like molecule. For a chain of size $M$, there is an effective folding transition to an ordered structure. Without frustration, this state is reached in a time that scales as $M^{\lambda}$, with $\lambda\simeq 3$. This scaling is limited by the amount of frustration which leads to the dynamical selectivity of proteins: foldable proteins are limited to $\sim 300$ monomers; and they are stable in {\it one} range of temperatures, independent of size and structure. These predictions explain generic properties of {\it in vivo} proteins.Comment: 4 pages, 4 Figures appended as postscript fil

Dimensional analysis and Rutherford Scattering

Dimensional analysis, and in particular the Buckingham $\Pi$ theorem is widely used in fluid mechanics. In this article we obtain an expression for the impact parameter from Buckingham's theorem and we compare our result with Rutherford's original discovery found in the early twentieth century

Effect of incidental teaching strategies on the workload in soccer. A systematic review.

El análisis realizado por la literatura existente acerca de los efectos que produce la utilización de estrategias de enseñanza incidentales en los atletas se ha realizado fundamentalmente bajo un prisma unidimensional, generalmente a través de los índices de rendimiento (cognitivo o motor), en términos de eficacia de las decisiones de los jugadores o de la precisión en los lanzamientos. Pero son escasos los trabajos que han estudiado el impacto de este tipo de estrategias bajo un prisma multidimensional, analizando además su efecto sobre variables de tipo fisiológico, como la frecuencia cardíaca, el movimiento ocular o el volumen máximo de oxígeno, o variables subjetivas, como el nivel de ansiedad, el rendimiento percibido o la percepción subjetiva del esfuerzo. Por todo ello, el objetivo del presente estudio es analizar bajo un prisma multidimensional el efecto de las estrategias de enseñanza incidentales sobre la carga de trabajo durante el aprendizaje de habilidades relacionadas con el fútbol, con objeto de conocer en qué aspectos benefician o perjudican el aprendizaje y el rendimiento de los jugadores. Se realizó una revisión sistemática de los estudios publicados hasta la actualidad. Se consultaron las bases de datos Web of Science, Scopus, SportDiscus with Full Text y PsycInfo, y revistas especializadas en la materia, además de realizar una revisión ascendente de la literatura seleccionada. Finalmente se seleccionaron 15 estudios. En base a los resultados obtenidos en los estudios seleccionados, en líneas generales podemos afirmar que los jugadores se ven beneficiados de una reducción de la cantidad de información que procesan intencionadamente para la resolución del problema que les plantea la tarea en habilidades relacionadas con el fútbol, siendo por tanto favorable la utilización de estrategias incidentales para dicho desempeño. No obstante, y debido a que las técnicas utilizadas para la evaluación del efecto de dicha estrategia han sido principalmente unidimensionales, se aconseja la utilización combinada de diferentes herramientas que consideren no sólo aspectos relacionados con el rendimiento, sino también medidas fisiológicas y psicológicas, con objeto de obtener una visión holística del efecto que este tipo de estrategia produce en los jugadores.The analysis made by the existing literature about the effects produced by the use of incidental teaching strategies in athletes has been carried out fundamentally under a one-dimensional prism, generally through performance indexes (cognitive or motor), in terms of efficiency of the decisions of the players or of the precision in the throws. But there are few studies that have studied the impact of this type of strategies under a multidimensional prism, also analyzing its effect on variables of physiological type, such as heart rate, eye movement or maximum volume of oxygen, or subjective variables, such as the level of anxiety, the perceived performance or the subjective perception of the effort. For all these reasons, the aim of this study is to analyze, under a multidimensional prism, the effect of incidental teaching strategies on the workload during the learning of soccer skills, in order to know in which aspects they benefit or harm learning. and the performance of the players. A systematic review of the studies published to date was carried out. We consulted the Web of Science databases, Scopus, SportDiscus with Full Text and PsycInfo, and specialized journals on the subject, as well as carrying out an upward revision of the selected literature. Finally, 15 studies were selected. Based on the results obtained in the selected studies, in general terms we can say that players benefit from a reduction in the amount of information they intentionally process to solve the problem posed by the task in soccer-related skills. being therefore favorable the use of incidental strategies for such performance. However, and because the techniques used to evaluate the effect of this strategy have been mainly one-dimensional, it is advisable to use different tools that consider not only aspects related to performance, but also physiological and psychological measures, with a view to to obtain a holistic view of the effect that this type of strategy produces on players