Hamilton-Jacobi Theory in k-Symplectic Field Theories

In this paper we extend the geometric formalism of Hamilton-Jacobi theory for Mechanics to the case of classical field theories in the k-symplectic framework

Nonholonomic constraints in kk-symplectic Classical Field Theories

A $k$-symplectic framework for classical field theories subject to nonholonomic constraints is presented. If the constrained problem is regular one can construct a projection operator such that the solutions of the constrained problem are obtained by projecting the solutions of the free problem. Symmetries for the nonholonomic system are introduced and we show that for every such symmetry, there exist a nonholonomic momentum equation. The proposed formalism permits to introduce in a simple way many tools of nonholonomic mechanics to nonholonomic field theories.Comment: 27 page

An experience on measuring students perception of workload to facilitate horizontal coordination

[EN] The main aim of this work was to design and test a systematic procedure to measure workload, in order to detect and correct anomalous values of it. Workload is one of the aspects of the teaching-learning environment that largely affect the academic attitude of any university student. Heavy workload or an improper distribution of it, in one or several subjects, can have an important impact on other subjects, hinders the organization of learning activities and assesment and promote students to adopt surface approaches to learning. We have made a pilot test to check and compare two different methods: a weekly questionnaire that measures the amount in hours of workload spent in each learning activity and a survey that quantifies student‘s perception of workload and which also includes opinions from the students about it. In both cases information is only requested on the out of class activities. Analysis and comparison of the results, allowed to contrast and qualify our initial idea while confirming the conclusions of some previous studies. After considering the feasibility of both methods, our university decided to apply the punctual survey of perceived workload. This paper describes the pilot test and presents the results of the first systematic measurement campaigns carried out.[ES] El principal objetivo de este trabajo fue diseñar y ensayar un procedimiento sistemático de medición de la carga de trabajo, orientado a detectar y corregir valores anómalos de esta. La carga de trabajo es uno de los aspectos del contexto académico que más afectan al comportamiento académico del estudiante universitario. Un exceso o una inadecuada distribución de la carga en una o varias asignaturas puede repercutir en las restantes, dificultar la organización de las actividades docentes y de evaluación y potenciar que los estudiantes adoptan enfoques superficiales de aprendizaje. Hemos realizado una prueba piloto para ensayar y comparar dos procedimientos distintos: un cuestionario semanal que evalúa la carga real en horas de cada actividad docente y una encuesta puntual que cuantifica la carga percibida por el estudiante en cada asignatura y en la que pueden incluirse también comentarios sobre la carga de trabajo. En ambos casos la información solicitada es únicamente sobre la carga no presencial. El análisis y la comparación de los datos obtenidos de la prueba piloto ha permitido contrastar y matizar nuestra idea inicial, además de confirmar las conclusiones de algunos estudios anteriores. Tras considerar la viabilidad de ambos procedimientos, nuestra Universidad decidió aplicar la encuesta puntual de carga percibida. En este trabajo describimos la prueba piloto realizada y presentamos los resultados de las primeras campañas de medición sistemática realizadasGarcía Martín, A.; García-León, J. (2017). Una experiencia de medición de la carga de trabajo percibida por los estudiantes para facilitar la coordinación horizontal. REDU. Revista de Docencia Universitaria. 15(1):81-104. doi:10.4995/redu.2017.5987.SWORD8110415

IL18 Gene Variants Influence the Susceptibility to Chagas Disease

Chagas disease is a parasitic disorder caused by the infection with the flagellated protozoan Trypanosoma cruzi. According to the World Health Organization, more than six million people are currently infected in endemic regions. Genetic factors have been proposed to influence predisposition to infection and development of severe clinical phenotypes like chronic Chagas cardiomyopathy (CCC). Interleukin 18 (IL18) encodes a proinflammatory cytokine that has been proposed to be involved in controlling T. cruzi infection. In this study, we analyzed the possible role of six IL18 gene variants (rs5744258, rs360722, rs2043055, rs187238, rs1946518 and rs360719), which cover most of the variation within the locus, in the susceptibility to infection by T. cruzi and/or CCC. In total, 1,171 individuals from a Colombian region endemic for Chagas disease, classified as seronegative (n = 595), seropositive asymptomatic (n = 175) and CCC (n = 401), were genotyped using TaqMan probes. Significant associations with T. cruzi infection were observed when comparing seronegative and seropositive individuals for rs187238 (P = 2.18E-03, OR = 0.77), rs360719 (P = 1.49E-03, OR = 0.76), rs2043055 (P = 2.52E-03, OR = 1.29), and rs1946518 (P = 0.0162, OR = 1.22). However, dependence analyses suggested that the association was mainly driven by the polymorphism rs360719. This variant is located within the promoter region of the IL18 gene, and it has been described that it creates a binding site for the transcription factor OCT-1 affecting IL-18 expression levels. In addition, no evidence of association was observed between any of the analyzed IL18 gene polymorphisms and the development of CCC. In summary, our data suggest that genetic variation within the promoter region of IL18 is directly involved in the susceptibility to infection by T. cruzi, which provides novel insight into disease pathophysiology and adds new perspectives to achieve a more effective disease control.This work is part of the doctoral thesis “Estudio de las bases genéticas de la enfermedad de Chagas” from the Biomedicine PhD program at the Universidad de Granada (Spain).Peer reviewe

Microwave energy supplied by a prototype oven prevents the spread of Fusarium wilt during the propagation of melon plantlets by seed

The re-use of propagation trays in nursery greenhouses is one of the main ways in which fusarium wilt is spread in melon crops (Cucumis melo). The causal agent of the disease is the fungus Fusarium oxysporum f. sp. melonis. This paper reports that exposing these seed trays to the energy produced by a prototype microwave oven during the commercial production of melon plantlets can prevent the spread of this pathogen with only a very small increase in production costs

Desarrollo de un equipo de fútbol de robots

El propósito de este artículo es mostrar una primer experiencia en la creación de un equipo de fútbol de robots. Se describe el funcionamiento del equipo INCASoT, diseñado para su presentación en la competencia CAFR-2003 (UBA), con una estrategia de control de robots (agentes) basada en una máquina de estados finitos. Esta máquina de estados especifica cómo un agente mantiene su posición, pasa la pelota y evade obstáculos. Los robots son organizados en formaciones con roles específicos de juego. INCASoT constituye la visión de un equipo básico de fútbol de robots.Eje: Inteligencia artificialRed de Universidades con Carreras en Informática (RedUNCI