4,006 research outputs found

    Imperfect bifurcations via topological methods in superlinear indefinite problems

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    In [5] the structure of the bifurcation diagrams of a class of superlinear indefinite problems with a symmetric weight was ascertained, showing that they consist of a primary branch and secondary loops bifurcating from it. In [4] it has been proved that, when the weight is asymmetric, the bifurcation diagrams are no longer connected since parts of the primary branch and loops of the symmetric case form an arbitrarily high number of isolas. In this work we give a deeper insight on this phenomenon, studying how the secondary bifurcations break as the weight is perturbed from the symmetric situation. Our proofs rely on the approach of [5,4], i.e. on the construction of certain Poincar\'e maps and the study of how they vary as some of the parameters of the problems change, constructing in this way the bifurcation diagrams.Comment: 13 pages, 7 figure

    La práctica del ciclismo indoor en los mayores: implicaciones metodológicas

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    Uno de los cambios más característicos de la época tecnológica en la que nos encontramos inmersos, es el envejecimiento de la población y la consecuente inversión de la pirámide poblacional. Dicha inversión, acentúa la necesidad de diseñar y extender planes de actuación que promuevan actividades físico-recreativas continuadas con intensidades, cargas y ejercicios específicos totalmente adaptados a las características de esta población. La propuesta que aquí presentamos se basa en la práctica del ciclo indoor, que representa una experiencia fundamental para el desarrollo integral de la persona. Esta práctica puede considerarse una terapia imprescindible para la estimulación y reeducación de las habilidades concretas de esta población, así como para la adquisición de técnicas de comunicación social, a la vez que realizan una actividad lúdica y placentera. Mediante un programa de actividad física de este tipo, se pretende aumentar las posibilidades funcionales, al tiempo que se mejora las psico-afectivas, y con ello la calidad de vida de nuestros mayores

    Deterministic Routing with HoL-Blocking-Awareness for Direct Topologies

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    AbstractRouting is a key design factor to obtain the maximum performance out of interconnection networks. Depending on the number of routing options that packets may use, routing algorithms are classified into two categories. If the packet can only use a single predetermined path, routing is deterministic, whereas if several paths are available, it is adaptive. It is well-known that adaptive routing usually outperforms deterministic routing. However, adaptive routers are more complex and introduces out-of-order delivery of packets. In this paper, we take up the challenge of developing a deterministic routing algorithm for direct topologies that can obtain a similar performance than adaptive routing, while providing the inherent advantages of deterministic routing such as in-order delivery of packets and implementation simplicity. The proposed deterministic routing algorithm is aware of the HoL-blocking effect, and it is designed to reduce it, which, as known, it is a key contributor to degrade interconnection network performance

    El proceso de comprensión lectora en alumnos de tercero de secundaria

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    El presente artículo describe el proceso lector seguido por estudiantes de tercero de secundaria para abordar un texto con el propósito de comprenderlo. Se utilizó un método de investigación mixto secuencial cuantitativo/cualitativo. En la fase cuantitativa se seleccionó una muestra de altos y bajos lectores, que fueron observados durante la ejecución de dos tareas, mediante las cuales se evidenció el proceso que siguieron al intentar comprender diversos textos. Los datos recabados en la fase cualitativa evidenciaron que no todos los alumnos siguen el mismo camino para lograr el propósito mencionado, por lo que se presenta un modelo que muestra las diferentes rutas seguidas y se identifica un conjunto de factores que intervienen en la elección de la ruta lectora, entre ellos el pensamiento metacognitivo y las creencias acerca de la lectura. The present article describes the reading process ninth-graders follow to address a text with the purpose of understanding it. A sequential mixed quantitative/qualitative method was used. In the quantitative phase, a sample of high and low readers was selected; these readers were observed while performing two tasks, which revealed the process they followed while attempting to understand diverse texts. The data compiled in the qualitative phase showed that not all students follow the same path to attain the designated purpose. A model is presented to show the different paths followed, and a set of factors that intervene in selecting the reading path is identified. These factors include metacognitive thinking and beliefs about reading.ITESO, A.C

    New insights into FoxE1 functions: identification of direct FoxE1 targets in thyroid cells

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    This is an open-access article distributed under the terms of the Creative Commons Attribution License.[Background]: FoxE1 is a thyroid-specific forkhead transcription factor essential for thyroid gland development, as well as for the maintenance of the thyroid differentiated state in adults. FoxE1 recognizes and binds to a short DNA sequence present in thyroglobulin (Tg) and thyroperoxidase (Tpo) promoters, but FoxE1 binding to regulatory regions other than Tg and Tpo promoters remains almost unexplored. Improving knowledge of the regulatory functions of FoxE1 is necessary to clarify its role in endocrine syndromes and cancer susceptibility. [Methodology/Principal Finding]:I n order to further investigate downstream FoxE1 targets, we performed a genome-wide expression screening after knocking-down FoxE1 and obtained new insights into FoxE1 transcriptional networks in thyroid follicular cells. After validation, we confirmed Adamts9, Cdh1, Duox2 and S100a4 as upregulated genes and Casp4, Creld2, Dusp5, Etv5, Hsp5a, Nr4a2 and Tm4sf1 as downregulated genes when FoxE1 was silenced. In promoter regions of putative FoxE1-regulated genes and also in the promoters of the classical thyroid genes Nis, Pax8 and Titf1, we performed an in silico search of the FoxE1 binding motif that was in close proximity to the NF1/CTF binding sequence, as previously described for other forkhead factors. Using chromatin immunoprecipitation we detected specific in vivo FoxE1 binding to novel regulatory regions in two relevant thyroid genes, Nis and Duox2. Moreover, we demonstrated simultaneous binding of FoxE1 and NF1/CTF to the Nis upstream enhancer region, as well as a clear functional activation of the Nis promoter by both transcription factors. [Conclusions/Significance]:In search for potential downstream mediators of FoxE1 function in thyroid cells, we identified two novel direct FoxE1 target genes. To our knowledge, this is the first evidence regarding the implication of Nis and Duox2 in executing the transcriptional program triggered by FoxE1. Furthermore, this study points out the important role of FoxE1 in the regulation of a large number of genes in thyroid cells. © 2013 Fernández et al.This work was supported by Grants BFU-2010-16025 from the Dirección General de Proyectos de Investigación; RD06/0020/0060 and RD12/0036/0030 from FIS, Instituto de Salud Carlos III; and S2011/BMD-2328 TIRONET project from the Comunidad de Madrid (Spain). LP Fernández holds a postdoctoral grant of the Juan de la Cierva programme of the Spanish Government.Peer Reviewe

    Transient Propagation and Scattering of Quasi-Rayleigh Waves in Plates: Quantitative comparison between Pulsed TV-Holography Measurements and FC(Gram) elastodynamic simulations

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    We study the scattering of transient, high-frequency, narrow-band quasi-Rayleigh elastic waves by through-thickness holes in aluminum plates, in the framework of ultrasonic nondestructive testing (NDT) based on full-field optical detection. Sequences of the instantaneous two-dimensional (2-D) out-of-plane displacement scattering maps are measured with a self-developed PTVH system. The corresponding simulated sequences are obtained by means of an FC(Gram) elastodynamic solver introduced recently, which implements a full three-dimensional (3D) vector formulation of the direct linear-elasticity scattering problem. A detailed quantitative comparison between these experimental and numerical sequences, which is presented here for the first time, shows very good agreement both in the amplitude and the phase of the acoustic field in the forward, lateral and backscattering areas. It is thus suggested that the combination of the PTVH system and the FC(Gram) elastodynamic solver provides an effective ultrasonic inspection tool for plate-like structures, with a significant potential for ultrasonic NDT applications.Comment: 46 pages, 16 figures, corresponding author Jos\'e Carlos L\'opez-V\'azquez, [email protected]. Changes: 1st, 4th, 5th paragraphs (intro), 3rd, 4th paragraphs (sec. 4); [59-60] cited only in appendixes; old ref. [52] removed; misprints corrected in the uncertainty of c_L (subsec. 3.1), citation to fig. 10 (sec. 4), size of images (caption fig.15); reference to Lam\'e constants removed in subsec. 3.

    Análisis biomecánico de la técnica individual del viraje en esquí alpino de competición

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    El objeto del presente estudio es evaluar la goniometría articular de los miembros inferiores de esquiadores en condiciones reales de competición así como la dinámica del CG y otras variables que nos permitan exponer una teoría explicativa sobre el viraje en esquí de competición. Para ello se han analizado tres esquiadores durante la realización de la prueba de Slalom del Campeonato del Mundo de Sierra Nevada 1996, considerarse dichos esquiadores del más alto nivel internacional al disputarse entre ellos las medallas del citado campeonato. Para su análisis se han utilizado técnicas fotogramétricas tridimensionales. Los resultados han puesto de manifiesto que, en condiciones de competición, los desplazamientos del CG del sistema se producen como consecuencia de la inclinación del esquiador hacia el centro de la curva y no por flexión articular, así la liberación de presión para desplazar los esquís hacia los cantos se realizará a expensas de dicho movimiento de inclinación

    Análisis cinemático del viraje en el esquí alpino de competición

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    Esta comunicación trata sobre la aplicación de la Biomecánica Deportiva como perspectiva científica, al análisis cinemático del esquí alpino como objeto de estudio, y ha sido realizada basándose en una situación real de competición como fue el Campeonato del Mundo de 1996 celebrado en Sierra Nevada (Granada). Para el análisis de la muestra, utilizamos la metodología y las tecnologías propias de la biomecánica Deportiva como son el método indirecto y las técnicas fotogramétricas tridimensionales, basadas en la filmación del gesto deportivo utilizando el vídeo. Los resultados obtenidos muestran la existencia de un patrón general de movimiento en la muestra de esquiadoras analizadas en cuanto a las velocidades tangenciales medias del CG(S).del sistema (esquiador más implementos). Entre las conclusiones, destacamos la existencia de una reducción de la velocidad tangencial media resultante en el recorrido analizado que es mayor aún, en el instante de paso del palo de viraje en particular y cuanto más curva es la trayectoria. Atendiendo a la desviación típica del comportamiento de la velocidad media resultante, podemos decir que en este tramo de paso de la puerta encontramos las diferencias entre la técnica individual de las esquiadoras analizadas. Este estudio nos confirma la importancia del entrenamiento en situación real de competición (en cuanto a material, características pista de entrenamiento, etc.

    Exfoliated graphite flakes as soft-electrodes for precisely contacting nanoobjects

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    This is the post-peer reviewed version of the following article: P. ares et al. “Exfoliated graphite flakes as soft-electrodes for precisely contacting nanoobjects”. 2D Matererials, 2015, 2(3): 035008. Which has been published in final form at:http://dx.doi.org/10.1088/2053-1583/2/3/035008We introduce a simple, clean and reliable method to transfer exfoliated graphite flakes as soft-electrodes for the electrical contacts of nano-objects. The microelectrodes thus produced exhibit extremely well-defined and thin edges and can be placed at any sample location with sub-micrometer precision. The procedure is carried out under ambient conditions and does not require chemical agents. We present electrical characterization of relevant examples including carbon nanotubes, metal-organic MMX nanoribbons, reduced graphene sheets and damaged circuit repair. The quality of the electrical contacts thus obtained is as good as those fabricated with conventional techniques. This technique is particularly relevant for conductive atomic force microscopy (AFM) studiesThis work was supported by Consolider CSD2010-0024, MAD2D-CM, S2013/MIT-3007 and MAT2013-46753-C2-1 and
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