From caging to rouse dynamics in polymer melts with intramolecular barriers: a critical test of the mode coupling theory

By means of computer simulations and solution of the equations of the mode coupling theory (MCT),we investigate the role of the intramolecular barriers on several dynamic aspects of nonentangled polymers. The investigated dynamic range extends from the caging regime characteristic of glass-formers to the relaxation of the chain Rouse modes. We review our recent work on this question,provide new results, and critically discuss the limitations of the theory. Solutions of the MCT for the structural relaxation reproduce qualitative trends of simulations for weak and moderate barriers. However, a progressive discrepancy is revealed as the limit of stiff chains is approached. This dis-agreement does not seem related with dynamic heterogeneities, which indeed are not enhanced by increasing barrier strength. It is not connected either with the breakdown of the convolution approximation for three-point static correlations, which retains its validity for stiff chains. These findings suggest the need of an improvement of the MCT equations for polymer melts. Concerning the relaxation of the chain degrees of freedom, MCT provides a microscopic basis for time scales from chain reorientation down to the caging regime. It rationalizes, from first principles, the observed deviations from the Rouse model on increasing the barrier strength. These include anomalous scaling of relaxation times, long-time plateaux, and nonmonotonous wavelength dependence of the mode correlators.

The role of intramolecular barriers on the glass transition of polymers: computer simulations versus mode coupling theory

We present computer simulations of a simple bead-spring model for polymer melts with intramolecular barriers. By systematically tuning the strength of the barriers, we investigate their role on the glass transition. Dynamic observables are analyzed within the framework of the mode coupling theory (MCT). Critical nonergodicity parameters, critical temperatures, and dynamic exponents are obtained from consistent fits of simulation data to MCT asymptotic laws. The so-obtained MCT λ-exponent increases from standard values for fully flexible chains to values close to the upper limit for stiff chains. In analogy with systems exhibiting higher-order MCT transitions, we suggest that the observed large λ-values arise form the interplay between two distinct mechanisms for dynamic arrest: general packing effects and polymer-specific intramolecular barriers. We compare simulation results with numerical solutions of the MCT equations for polymer systems, within the polymer reference interaction site model (PRISM) for static correlations. We verify that the approximations introduced by the PRISM are fulfilled by simulations, with the same quality for all the range of investigated barrier strength. The numerical solutions reproduce the qualitative trends of simulations for the dependence of the nonergodicity parameters and critical temperatures on the barrier strength. In particular, the increase in the barrier strength at fixed density increases the localization length and the critical temperature. However the qualitative agreement between theory and simulation breaks in the limit of stiff chains. We discuss the possible origin of this feature.

Dynamic arrest in polymer melts: competition between packing and intramolecular barriers

We present molecular dynamics simulations of a simple model for polymer melts with intramolecular barriers. We investigate structural relaxation as a function of the barrier strength. Dynamic correlators can be consistently analyzed within the framework of the mode coupling theory of the glass transition. Control parameters are tuned in order to induce a competition between general packing effects and polymer-specific intramolecular barriers as mechanisms for dynamic arrest. This competition yields unusually large values of the so-called mode coupling theory exponent parameter and rationalizes qualitatively different observations for simple bead-spring and realistic polymers. The systematic study of the effect of intramolecular barriers presented here also establishes a fundamental difference between the nature of the glass transition in polymers and in simple glass formers.

Shifted loops and coercivity from field imprinted high energy barriers in ferritin and ferrihydrite nanoparticles

We show that the coercive field in ferritin and ferrihydrite depends on the maximum magnetic field in a hysteresis loop and that coercivity and loop shifts depend both on the maximum and cooling fields. In the case of ferritin, we show that the time dependence of the magnetization also depends on the maximum and previous cooling fields. This behavior is associated to changes in the intraparticle energy barriers imprinted by these fields. Accordingly, the dependence of the coercive and loop-shift fields with the maximum field in ferritin and ferrihydrite can be described within the frame of a uniform-rotation model considering a dependence of the energy barrier with the maximum and the cooling fields.

Approaches to the study of individual–landscape interaction as an evocation of intrapersonal communication Aproximaciones al estudio de la interacción individuo-paisaje a modo de evocación comunicativa intrapersonal

Analysis of the interaction between landscape and the individual opens up many research avenues linked to the generation and interpretation of symbolisms and imaginaries. The capacity of landscape for significant and/or communicative evocation finds in intrapersonal communication a relevant argument for the construction of a theoretical framework to study the process of appropriation and experience of the landscape in terms of communicative expression. The principal aim of this paper is to set up the theoretical framework that enables us to interpret the language of landscape and to decode its intangible discourse.

Perceived Barriers to Physical Activity and Related Factors in Spanish University Students

Objective: The purpose of this study was to identify the influence of readiness of change for physical activity (PA), sociodemographic factors, lifestyle and physical activity status (PAS) on perceived barriers among Spanish university students. Participants: Seven hundred and seventy two (n = 772) men and women ages 17 - 39 at a north-west regional university in Spain participated in the study. Methods: The International Physical Activity Questionnaire, the States of Change for Physical Activity Behaviour Questionnaire and the Self-perceived Barriers for Physical Activity Questionnaire were used. Description, correlation and multiple regression analyses were completed. Results: Participants self-perceived low average-score barriers (2.6 ± 1.4 over 10.0). The 3-higher scores barriers corresponded to “too much work”; “lack of time for exercise” and “laziness”. Gender, PAS and self-perceived health were shown to be associated with perceived barriers. Conclusions: University institutions should consider those factors that predict barriers to PA to develop effective intervention programs.

Comunicación Terapéutica : Requisitos fundamentales para acompañar emocionalmente al paciente paliativo y su familia.

La comunicación entre los enfermeros y los pacientes oncológicos es fundamental en la construcción de la relación profesional y terapéutica y esencial para administrar unos cuidados realmente enfocados en la persona como ser holístico y no como entidad patológica. Diferentes estudios han demostrado la influencia positiva de la comunicación en la satisfacción del paciente e incluso se ha encontrado relación entre una comunicación efectiva y una mayor adherencia al tratamiento, mejor control del dolor y estado psicológico. La comunicación, como herramienta para establecer una relación terapéutica eficaz, a su vez básica para el cuidado de cualquier paciente, es entonces “la herramienta” y prerrequisito indispensable para cuidar estos pacientes desde una perspectiva holística. Pese a la centralidad en el cuidado enfermero, la comunicación no se emplea en modo correcto en muchos casos. Objetivos: Este trabajo tiene como objetivo individuar las principales habilidades (skills) para lograr una comunicación terapéutica eficaz y cómo emplearlas en la construcción y mantenimiento de la relación terapéutica con el paciente y su familia. Método: búsqueda bibliográfica con las siguientes palabras clave: comunicación, paliativos, enfermería. Se han incluido en la revisión 27 artículos de 17 revistas distintas. Resultados: Las habilidades y factores encontrados en la literatura han sido clasificados en: a. barreras a la comunicación terapéutica b. condiciones y habilidades facilitadoras de la comunicaciónvi c. habilidades de relación d. habilidades para solicitar información e. estrategias y modelos de comunicación Conclusiones: La comunicación es la herramienta principal del cuidado enfermero en cuidados paliativos, difiere de la comunicación social y tiene como objetivo aumentar la calidad de vida del paciente. La habilidad en comunicación no es un don innato sino que es el resultado de un proceso de aprendizaje continuo. Entre las habilidades más citadas y efectivas hay que recordar la escucha activa (entendida como conjunto de técnicas), el tacto terapéutico, el contacto visual, la empatía y la importancia fundamental de la comunicación no verbal. El modelo de comunicación COMFORT es el único centrado en el paciente y a la vez en su familia. Palabras clave: Habilidades comunicación, paliativos, enfermería

Barriers and Motivators for Using Open Educational Resources in Schools

In an explorative study, we investigated on German schoolteachers how they use, reuse, produce and manage Open Educational Resources. The main questions in this research have been, what their motivators and barriers are in their use of Open Educational Resources, what others can learn from their Open Educational Practices, and what we can do to raise the dissemination level of OER in schools.

Web and education, a successful open entanglement

E-learning, understood as the intensive use of Information and Communication Technologies in mainly but not only) distance education, has radically changed the meaning of the latter. E-learning is an overused term which has been applied to any use of technology in education. Today, the most widely accepted meaning ofe-learning coincides with the fourth generation described by Taylor (1999), where there is an asynchronousprocess that allows students and teachers to interact in an educational process expressly designed in accordance with these principles. We prefer to speak of Internet-Based Learning or, better still, Web-Based Learning, for example, to explain the fact that distance education is carried out using the Internet, with the appearance of the virtual learning environment concept, a web space where the teaching and learning process is generated and supported (Sangrà, 2002). This entails overcoming the barriers of space and time of brickand mortar education (although we prefer the term face-to-face) or of classical distance education using broadcasting and adopting a completely asynchronous model that allows access to education by many more users, at any level (including secondary education, but primarily higher education and lifelong learning).

Protocolo de comunicación trabajador-robot mediante imágenes

La idea del proyecto viene del concepto de “fábricas del futuro”, donde las barreras entre robots y humanos se rompen para que la colaboración entre ambos sea como en un equipo. Para la realización de este proyecto se ha utilizado el brazo robótico IRB120 de la marca ABB de 6 Grados de libertad, Matlab y el software Robot Studio. El Objetivo principal de este proyecto es establecer el protocolo de comunicación trabajador-robot mediante imágenes. El trabajador debería poder controlar el robot mediante dibujos realizados en la mesa de trabajo. En el desarrollo de la comunicación trabajador-robot cabe distinguir tres partes: · El análisis y tratamiento de imágenes para el cual se ha utilizado el software Matlab. · Transmisión de los datos desde Matlab al robot. · Programación de las acciones a realizar por el robot mediante el software “Robot Studio”. Con el protocolo de comunicación desarrollado y las imágenes realizadas por el trabajador el robot es capaz de detectar lo siguiente: · la herramienta que debe utilizar (rotulador, boli o ventosa) · si lo que tiene que dibujar en la mesa de trabajo son puntos o trazo continuo. · la localización de los puntos o del trazo continuo en la mesa de trabajo. Se ha alcanzado el objetivo propuesto con éxito, el protocolo de comunicación trabajador-robot mediante imágenes ha sido establecido. Mediante el análisis y tratamiento de imágenes se puede conseguir la información necesaria para que el robot pueda ejecutar las acciones requeridas por el trabajador.

The evolution of post-zygotic isolation barriers by immune-triggered hybrid incompatibilities in Arabidopsis thaliana

A long-standing question in evolutionary biology is what defines a species. The biological species concept considers a species as a population of individuals that interbreeds freely and produces viable offspring. Therefore, reproductive isolation is the essence of species. Hybrid necrosis is one form of post-zygotic reproductive isolation. In this chapter, we summarize what is known to date about this phenomenon and highlight progress made in the understanding of these immune-triggered hybrid incompatibilities through our research in the plant model Arabidopsis thaliana.

Core communication components along the cancer care process: the perspective of breast cancer patients

This study sought to assess the impact of health care professional (HCP) communication on breast cancer patients across the acute care process as perceived by patients. Methodological approach was based on eight focus groups conducted with a sample of patients (n ¼ 37) drawn from 15 Spanish Regions; thematic analysis was undertaken using the National Cancer Institute (NCI) framework of HCP communication as the theoretical basis. Relevant results of this study were the identification of four main communication components: (1) reassurance in coping with uncertainty after symptom detection and prompt access until confirmed diagnosis; (2) fostering involvement before delivering treatments, by anticipating information on practical and emotional illness-related issues; (3) guidance on the different therapeutic options, through use of clinical scenarios; and, (4) eliciting the feeling of emotional exhaustion after ending treatments and addressing the management of potential treatment-related effects. These communication-related components highlighted the need for a comprehensive approach in this area of cancer care

The evolution of post-zygotic isolation barriers by immune-triggered hybrid incompatibilities in Arabidopsis thaliana

A long-standing question in evolutionary biology is what defines a species. The biological species concept considers a species as a population of individuals that interbreeds freely and produces viable offspring. Therefore, reproductive isolation is the essence of species. Hybrid necrosis is one form of post-zygotic reproductive isolation. In this chapter, we summarize what is known to date about this phenomenon and highlight progress made in the understanding of these immune-triggered hybrid incompatibilities through our research in the plant model Arabidopsis thaliana.

A Markov chain analysis of emotional exchange in voice-to-voice communication: Testing for the mimicry hypothesis of emotional contagion

Mimicry is a central plank of the emotional contagion theory; however, it was only tested with facial and postural emotional stimuli. This study explores the existence of mimicry in voice-to-voice communication by analyzing 8,747 sequences of emotional displays between customers and employees in a call-center context. We listened live to 967 telephone inter-actions, registered the sequences of emotional displays, and analyzed them with a Markov chain. We also explored other propositions of emotional contagion theory that were yet to be tested in vocal contexts. Results supported that mimicry is significantly present at all levels. Our findings fill an important gap in the emotional contagion theory; have practical implications regarding voice-to-voice interactions; and open doors for future vocal mimicry research.

Mobile Communication 2012 : Experiències i recerques sobre comunicació mòbil

La comunicació mòbil és un dels temes de més actualitat en diferents fòrums, des de diferents perspectives. Espanya juga un paper important per les dinàmiques i l’evolució del seu mercat. En aquest sentit, el nostre país ofereix un interès específic per l'amplitud del seu parc de dispositius 3G (el segon d'Europa, després d'Itàlia) i per la intensitat del desenvolupament de xarxes socials mòbils, a més de per la creixent implicació d'empreses en la producció i distribució de continguts mòbils. Com va passar amb Internet, es tracta d’un procés d'innovació pel qual els formats de contingut, les pràctiques de consum i els models de negoci característics de la televisió i la xarxa, per exemple, s'adapten, primer, al nou mitjà, per a després desenvolupar formes i models específics que aprofiten les potencialitats de personalització, geolocalització i conectivitat ubiqua.