A symmetric quantum calculus

We introduce the $\alpha,\beta$-symmetric difference derivative and the $\alpha,\beta$-symmetric N\"orlund sum. The associated symmetric quantum calculus is developed, which can be seen as a generalization of the forward and backward $h$-calculus.Comment: Submitted 26/Sept/2011; accepted in revised form 28/Dec/2011; to Proceedings of International Conference on Differential & Difference Equations and Applications, in honour of Professor Ravi P. Agarwal, to be published by Springer in the series Proceedings in Mathematics (PROM

Evolution Strategies in Optimization Problems

Evolution Strategies are inspired in biology and part of a larger research field known as Evolutionary Algorithms. Those strategies perform a random search in the space of admissible functions, aiming to optimize some given objective function. We show that simple evolution strategies are a useful tool in optimal control, permitting to obtain, in an efficient way, good approximations to the solutions of some recent and challenging optimal control problems.Comment: Partially presented at the 5th Junior European Meeting on "Control and Information Technology" (JEM'06), Sept 20-22, 2006, Tallinn, Estonia. To appear in "Proceedings of the Estonian Academy of Sciences -- Physics Mathematics

A symmetric Norlund sum with application to inequalities

Properties of an $\alpha,\beta$-symmetric Norlund sum are studied. Inspired in the work by Agarwal et al., $\alpha,\beta$-symmetric quantum versions of Holder, Cauchy-Schwarz and Minkowski inequalities are obtained.Comment: Submitted 18-Oct-2011; accepted 09-March-2012; to Proceedings of International Conference on Differential & Difference Equations and Applications, in honour of Professor Ravi P. Agarwal, to be published by Springer in the series Proceedings in Mathematics (PROM

Parenting style: influence on gifted children psychological adjustment

Este trabajo se centra en las influencias positivas y negativas de la práctica educativa que los padres ejercen sobre el desarrollo de los niños con altas capacidades. El resultado de este estudio teórico muestra que las familias cuyas características esenciales están basadas en una dinámica de funcionamiento en la que priman la armonía y la coherencia se asocian tanto al desarrollo óptimo intelectual y de la autoestima como al adecuado funcionamiento emocional e intelectual. En contraste, las familias en las que la falta de coherencia y la existencia de una dinámica de funcionamiento caracterizada por bajos niveles de comunicación, afecto y control del comportamiento se asocian a la aparición de comportamientos de riesgo. De acuerdo con la literatura existente, las prácticas educativas más efectivas para el ajuste y bienestar de niños y adolescentes son las autoritativas. En el caso de los niños con altas capacidades, la mayoría de los padres se muestran acordes con estas prácticas de crianza aunque en algunos casos se han encontrado diferencias en las pautas de actuación de madres y padres. Los determinantes parentales que potencian el ajuste positivo de los hijos con altas capacidades son: nivel intelectual, nivel educativo y rendimiento académico alto, y en ausencia de estas características, interés de los padres hacia la educación y el aprendizaje.This paper focused on influence of parenting practice on gifted children´s development. The result of this study showed that harmony and coherent families are associated both to self-stem, effective intellectual development and social and emotional functioning. In contrast, family discord relates to risk behaviour. According to literature, the most effective parenting practice for children development is authoritative, In gifted children case, most of the parents showed educative patterns framed in the authoritative parenting style although in some cases it was found differences between mother and father. Parents determinants making possible positive adjustement in their gifted children are: high intellectual level, high school achievement and high level of school performance. In absence of this, parent´s high interest on education and learning act as a substitute of these last cognitive and educational characteristics.peerReviewe

The Brightest Cluster Galaxy in Abell 85: The Largest Core Known so far

We have found that the brightest cluster galaxy (BCG) in Abell~85, Holm 15A, displays the largest core so far known. Its cusp radius, $r_{\gamma} = 4.57 \pm 0.06$ kpc ($4.26^{\prime\prime}\pm 0.06^{\prime\prime}$), is more than 18 times larger than the mean for BCGs, and $\geq1$ kpc larger than A2261-BCG, hitherto the largest-cored BCG (Postman, Lauer, Donahue, et al. 2012) Holm 15A hosts the luminous amorphous radio source 0039-095B and has the optical signature of a LINER. Scaling laws indicate that this core could host a supermassive black hole (SMBH) of mass $M_{\bullet}\thicksim (10^{9}-10^{11})\,M_{\odot}$. We suggest that cores this large represent a relatively short phase in the evolution of BCGs, whereas the masses of their associated SBMH might be set by initial conditions.Comment: 14 pages, 3 figure, 2 tables, accepted for publication in ApJ Letters on October 6th, 2014, replacement of previous manuscript submitted on May 30th, 2014 to astro-p

Successful organizational learning in the management of agricultural research and innovation: The Mexican produce foundations

"Since the 1980s, developing countries' agriculture has become more complex and diversified. In general, the public research and extension institutions in these countries were criticized for not participating in the emergence of the most dynamic agricultural markets. In recent years, many of these institutions have struggled to adapt to the new environment but they could not overcome the hurdles posed by organizational rigidities, strict public regulations, deteriorating human capital, shrinking budgets and a model of science that hampered their integration into dynamic innovation processes. In general, developing countries applied similar agricultural research policies: separation of financing and implementation of research, reductions in direct budgetary allocations to research and extension institutions, elimination or major reduction of public extension, and introduction of competitive grants programs to induce a transformation of research organizations. Strong anecdotal information suggests that these policies had limited impact on the quality and pertinence of research, and on the performance of the public research institutions. Using a different set of instruments, the Mexican Produce Foundations (PF) had major and diverse impacts on the agricultural innovation and research systems. These impacts resulted mostly from activities the PF introduced as they learned to manage funds for research and extension, and to a lesser extent from the activities they were created for, i.e., manage a competitive fund for agricultural research and extension. The PF were able to introduce these activities because they developed strong abilities to learn, including identifying knowledge gaps and defining strategies to fill them. The questions this report seeks to answer are how an organization that manages public funds for research and extension could sustain organizational innovations over extended periods, and how it could learn and adapt to maximize its impact on the agricultural innovation system. Previous studies found that human resources, organizational cultures and governance structures are three of the most important factors influencing institutional change and innovative capabilities. Despite their importance, these factors have been largely neglected in the literature on agricultural research and extension policies. This document analyzes what role these factors played in the Mexican experience." from textAgricultural research, Agricultural innovation, Developing countries,

Desarrollo de semiconductores con estructuras tipo perovskitas para purificar el agua mediante oxidaciones avanzadas

En este trabajo se llevó a cabo la preparación a través del método sol-gel y la reacción en estado sólido de óxidos semiconductores pertenecientes a las familias del tipo perovskita simple, ABO3 y doble laminar, A2M2O7, como el NaTaO3, NaTaO3:A (A = La, Sm), y Sr2M2O7 (M = Ta, Nb), respectivamente. Éstos fueron probados en la reacción de degradación fotocatalítica de azul de metileno, cristal violeta y rojo alizarín S. En particular, la perovskita simple, NaTaO3:Sm, mostró la mejor eficiencia para la degradación de azul de metileno (t1/2 = 65 min), mientras que la perovskita doble laminar, Sr2Ta2O7, fue eficiente para degradar tanto el cristal violeta (t1/2 = 5 min), como el rojo alizarín S (t1/2 = 25 min). Para el caso del cristal violeta la eficiencia fue incluso mayor a la mostrada por la titania P25 Degussa. La eficiencia fotocatalítica mostrada por los óxidos tipo perovskita simple la hemos relacionado a la formación de su estructura cristalina y a los valores de área superficial específica, además del efecto favorable del dopante. Mientras que en el caso de los óxidos tipo perovskita laminar, la eficiencia se debió a la presencia de la fase cristalina y al pH del medio de reacción. Además, debido a que todos estos óxidos mostraron valores de Eg alrededor de 4.0 eV, su activida

Osteocondritis disecante de la cabeza del 2º metacarpiano en un niño: a propósito de un caso

La osteocondritis disecante en articulaciones de la mano es un proceso muy raro, sólo existen dos casos previos publicados en la literatura. Presentamos un paciente de 10 años de edad con dolor e impotencia funcional de la articulación metacarpofalángica de la mano izquierda de semanas de evolución. Con el diagnós - tico final de osteocondritis disecante realizamos una resección del fragmento libre asociadas a perforaciones con aguja fina. Tras el primer año de seguimiento el paciente se encuentra asintomático y se observa remodelación casi completa de la superficie articular.Ostheocondritis in the hand is a rare process. Only two cases were reported in the previous litera - ture. In this report we present a 10 years old boy with pain and a few functional limitation in second metacarpal phalangeal joint for weeks. With the final diagnosis of osteochondritis dissecans we performed surgery. Intraope - ratively the cartilage flap was removed and some drilling was realized. Before one year the patient was asympto - matic and we observed an improvement of articular surface