Noise and dynamics of self-organized critical phenomena

Different microscopic models exhibiting self-organized criticality are studied numerically and analytically. Numerical simulations are performed to compute critical exponents, mainly the dynamical exponent, and to check universality classes. We find that various models lead to the same exponent, but this universality class is sensitive to disorder. From the dynamic microscopic rules we obtain continuum equations with different sources of noise, which we call internal and external. Different correlations of the noise give rise to different critical behavior. A model for external noise is proposed that makes the upper critical dimensionality equal to 4 and leads to the possible existence of a phase transition above d=4. Limitations of the approach of these models by a simple nonlinear equation are discussed.

Finite-size scaling investigation of the liquid-liquid critical point in ST2 water and its stability with respect to crystallization.

The liquid-liquid critical point scenario of water hypothesizes the existence of two metastable liq- uid phases low-density liquid (LDL) and high-density liquid (HDL) deep within the supercooled region. The hypothesis originates from computer simulations of the ST2 water model, but the stabil- ity of the LDL phase with respect to the crystal is still being debated. We simulate supercooled ST2 water at constant pressure, constant temperature, and constant number of molecules N for N ≤ 729 and times up to 1 μs. We observe clear differences between the two liquids, both structural and dynamical. Using several methods, including finite-size scaling, we confirm the presence of a liquid-liquid phase transition ending in a critical point. We find that the LDL is stable with respect to the crystal in 98% of our runs (we perform 372 runs for LDL or LDL-like states), and in 100% of our runs for the two largest system sizes (N = 512 and 729, for which we perform 136 runs for LDL or LDL-like states). In all these runs, tiny crystallites grow and then melt within 1 μs. Only for N ≤ 343 we observe six events (over 236 runs for LDL or LDL-like states) of spontaneous crystal- lization after crystallites reach an estimated critical size of about 70 ± 10 molecules.

Meissner effect and critical fields in an inhomogeneous Ba2HoCu3O7-x high-Tc superconductor

The Meissner and diamagnetic shielding effects and the upper, lower, and thermodynamical critical fields have been studied in a Ba2HoCu3O7-x sample using magnetization measurements in fields up to 55 kOe. The diamagnetic shielding curve shows the existence of a transition at Tc=91.5 K followed by a broad transition extending from 85 to 25 K which may be related to inhomogeneities in the oxygen content of the sample. A rather low flux expulsion (13.5%) is observed which we attribute to flux pinning or trapping. We show that the coexistence of superconducting and nonsuperconducting regions within the sample at temperatures just below Tc leads to strong reductions in the critical magnetic fields.

Quantum critical effects in mean-field glassy systems

We consider the effects of quantum fluctuations in mean-field quantum spin-glass models with pairwise interactions. We examine the nature of the quantum glass transition at zero temperature in a transverse field. In models (such as the random orthogonal model) where the classical phase transition is discontinuous an analysis using the static approximation reveals that the transition becomes continuous at zero temperature.

Evidence of a critical time in constrained Kinetic Ising models

We study the relaxational dynamics of the one-spin facilitated Ising model introduced by Fredrickson and Andersen. We show the existence of a critical time which separates an initial regime in which the relaxation is exponentially fast and aging is absent from a regime in which relaxation becomes slow and aging effects are present. The presence of this fast exponential process and its associated critical time is in agreement with some recent experimental results on fragile glasses.

1st Conference on Arts-Based and Artistic Research. Critical reflections on the intersection between art and research

[eng] Proceedings for the 1st Conference on Arts-Based and Artistic Research: Critical Reflections on the Intersection of Art and Research. University of Barcelona, January 31st - February 1st, 2013.

Pathway databases and tools for their exploitation: benefits, current limitations and challenges

In past years, comprehensive representations of cell signalling pathways have been developed by manual curation from literature, which requires huge effort and would benefit from information stored in databases and from automatic retrieval and integration methods. Once a reconstruction of the network of interactions is achieved, analysis of its structural features and its dynamic behaviour can take place. Mathematical modelling techniques are used to simulate the complex behaviour of cell signalling networks, which ultimately sheds light on the mechanisms leading to complex diseases or helps in the identification of drug targets. A variety of databases containing information on cell signalling pathways have been developed in conjunction with methodologies to access and analyse the data. In principle, the scenario is prepared to make the most of this information for the analysis of the dynamics of signalling pathways. However, are the knowledge repositories of signalling pathways ready to realize the systems biology promise? In this article we aim to initiate this discussion and to provide some insights on this issue.

Traces of functions in Fock spaces on lattices of critical density

Following a scheme of Levin we describe the values that functions in Fock spaces take on lattices of critical density in terms of both the size of the values and a cancelation condition that involves discrete versions of the Cauchy and Beurling-Ahlfors transforms.

Using Songs in Primary Education: Advantages and Challenges

Aquesta recerca està basada en l’observació de les cançons per aprendre i ensenyar la llengua anglesa en l’etapa d’Educació Primària. S’analitza la cançó com un recurs eficaç per aprendre aquesta llengua, així com també s’observen els avantatges i desavantatges que es poden trobar en l’ús de les cançons a les aules de Primària. A partir d’una aplicació pràctica també s’estudia la validesa d’aquest recurs en el primer i darrer curs de la Primària. A més a més, es mesura la motivació que mostren els alumnes davant d’aquesta eina d’aprenentatge. Finalment, es presenten els resultats obtinguts en l’aplicació pràctica que s’ha portat a terme en una escola i les conclusions que s’extreuen a partir de la justificació teòrica i els resultats obtinguts a partir de les sessions pràctiques.

Challenges and opportunities for science journalists in adopting new technologies: the case of Spain = Retos y oportunidades para los periodistas científicos en la adopción de las nuevas tecnologías: el caso de España

This paper analyses the adoption of new information and communication technologies (ICTs) by Spanish journalists specialising in science. Applying an ethnographic research model, this study was based on a wide sample of professionals, aiming to evaluate the extent by which science journalists have adopted the new media and changed the way they use information sources. In addition, interviewees were asked whether in their opinion the Web 2.0 has had an impact on the quality of the news. The integration of formats certainly implies a few issues for today’s newsrooms. Finally, with the purpose of improving the practice of science information dissemination, the authors put forward a few proposals, namely: Increasing the training of Spanish science journalists in the field of new technologies; Emphasising the accuracy of the information and the validation of sources; Rethinking the mandates and the tasks of information professionals.

FDNY Facing Future Challenges with ICS

View of Ground Zero showing destroyed buildings and those with major structural damage (viewed from southwest).

Repensar el asesoramiento en educación. ¿Qué prácticas para los nuevos retos? = Rethink the advice in education. What practices for the new challenges?

Esta publicación aborda, de manera monográfica, el tema del asesoramiento en educación. Han transcurrido prácticamente treinta años desde que a finales de los 70 y principios de los 80 surgieran en nuestro país los Servicios de Orientación Educativa y Vocacional (SOEV), que junto a los Institutos de Orientación Educativa y Profesional (IOEP) y los Equipos Multiprofesionales (EM) dan origen –en los 90– a los actuales Equipos de Orientación Educativa y Psicopedagógica (EOEP). Han pasado veinticinco años desde el nacimiento en España –a mediados de los 80– de los Centros de Profesores (CEP). Inspirados en los ‘Teachers Centers’ británicos, los CEP vienen a cubrir las necesidades de formación permanente del profesorado como respuesta a la inoperancia de los Institutos de Ciencias de la Educación (ICE) del momento. Han sido, pues, treinta años de lo que ha venido a llamarse asesoramiento institucional, esto es, asesoramiento organizado y estructurado, ofertado desde sistemas de apoyo a la escuela, dando cabida en u actuación a multitud de iniciativas y prácticas de apoyo entre las que se encuentran las de asesoramiento, entremezclándose y confundiéndose a veces como prácticas de orientación, a veces como formación, o simplemente como actividades de asistencia y colaboración entre profesionales para la resolución de necesidades y problemas en el seno de nuestras escuelas. Y tal ha sido su diversidad y tipología, su riqueza y amplitud, que se han invertido no pocos esfuerzos, debates y ríos de tinta para comprender y definir, clasificar y etiquetar un ingente y variopinto conjunto de prácticas que convenimos en llamar, de asesoramiento