Random-field Potts model with dipolarlike interactions: Hysteresis avalanches and microstructure

A model for the study of hysteresis and avalanches in a first-order phase transition from a single variant phase to a multivariant phase is presented. The model is based on a modification of the random-field Potts model with metastable dynamics by adding a dipolar interaction term truncated at nearest neighbors. We focus our study on hysteresis loop properties, on the three-dimensional microstructure formation, and on avalanche statistics.

Potts fully frustrated model: Thermodynamics, percolation and dynamics in two dimensions

We consider a Potts model diluted by fully frustrated Ising spins. The model corresponds to a fully frustrated Potts model with variables having an integer absolute value and a sign. This model presents precursor phenomena of a glass transition in the high-temperature region. We show that the onset of these phenomena can be related to a thermodynamic transition. Furthermore, this transition can be mapped onto a percolation transition. We numerically study the phase diagram in two dimensions (2D) for this model with frustration and without disorder and we compare it to the phase diagram of (i) the model with frustration and disorder and (ii) the ferromagnetic model. Introducing a parameter that connects the three models, we generalize the exact expression of the ferromagnetic Potts transition temperature in 2D to the other cases. Finally, we estimate the dynamic critical exponents related to the Potts order parameter and to the energy.

Les preferències dels usuaris estudiants per les prestacions dels OPACs de pròxima generació

L'objectiu d'aquest article és identificar les prestacions preferides pels usuaris estudiants internacionals per als OPACs de pròxima generació. La metodologia seguida va ser entrevistar el juliol de 2008 setze estudiants internacionals de la University of Sheffield per explorar les seves preferències entre les prestacions potencials en els OPACs de pròxima generació. Es va utilitzar un esquema d'entrevista semi-estructurat amb imatges de simulacions de pantalles. Els resultats de les entrevistes van concordar àmpliament amb els estudis previs. En general, els estudiants esperen que les prestacions dels OPACs de pròxima generació els estalviin temps, siguin fàcils d'utilitzar i que siguin rellevants per a la seva cerca. Aquest estudi va descobrir que els usuaris prefereixen les prestacions de recomanació i les prestacions que proporcionen una millor navegació entre els resultats de cerca. No obstant això, les prestacions Web 2.0, com ara els agregadors i les prestacions que implicaven la participació dels usuaris es trobaven entre les menys populars.

Production of OER, a Quest for Efficiency

In most initiatives to publish Open Educational Resources (OER), the production of OER is the activity with the highest costs. Based on literature and personal experiences a list of relevant characteristics of production processes for OER are determined. Three cases are compared with each other on these characteristics. Most influence on costs are human costs and the type of OER created.

Towards a user-friendly webservice architecture for statistical machine translation in the PANACEA project

This paper presents a webservice architecture for Statistical Machine Translation aimed at non-technical users. A workfloweditor allows a user to combine different webservices using a graphical user interface. In the current state of this project,the webservices have been implemented for a range of sentential and sub-sententialaligners. The advantage of a common interface and a common data format allows the user to build workflows exchanging different aligners.

Réquiem por la muerte del yo artista

RÉQUIEM POR LA MUERTE DEL YO ARTISTA es un proyecto audiovisual en forma de performance sobre la música del compositor finlandés contemporáneo Einojuhani Rautavaara, los Requiem del poeta alemán Rainer Maria Rilke y la concepción filosófica del arte y su comercialidad del artista americano Andy Warhol. RÉQUIEM POR LA MUERTE DEL YO ARTISTA es mi sangre. Es mi compromiso. Trata sobre la dualidad entre el artista y la persona, y cómo esto afecta a nuestro arte. RÉQUIEM POR LA MUERTE DEL YO ARTISTA es una operación de corazón. Es provocación; es sobre vomitar tu mente y estar sediento de futuro. Es comerte a ti mismo. Pero sobre todo, es mi concepción de arte: arte es todo aquello por lo que el creador esté dispuesto a morir.

Diffusionless first-order phase transitions in systems with frozen configurational degrees of freedom

We consider systems that can be described in terms of two kinds of degree of freedom. The corresponding ordering modes may, under certain conditions, be coupled to each other. We may thus assume that the primary ordering mode gives rise to a diffusionless first-order phase transition. The change of its thermodynamic properties as a function of the secondary-ordering-mode state is then analyzed. Two specific examples are discussed. First, we study a three-state Potts model in a binary system. Using mean-field techniques, we obtain the phase diagram and different properties of the system as a function of the distribution of atoms on the different lattice sites. In the second case, the properties of a displacive structural phase transition of martensitic type in a binary alloy are studied as a function of atomic order. Because of the directional character of the martensitic-transition mechanism, we find only a very weak dependence of the entropy on atomic order. Experimental results are found to be in quite good agreement with theoretical predictions.

Precursor phenomena in frustrated systems

To understand the origin of the dynamical transition, between high-temperature exponential relaxation and low-temperature nonexponential relaxation, that occurs well above the static transition in glassy systems, a frustrated spin model, with and without disorder, is considered. The model has two phase transitions, the lower being a standard spin glass transition (in the presence of disorder) or fully frustrated Ising (in the absence of disorder), and the higher being a Potts transition. Monte Carlo results clarify that in the model with (or without) disorder the precursor phenomena are related to the Griffiths (or Potts) transition. The Griffiths transition is a vanishing transition which occurs above the Potts transition and is present only when disorder is present, while the Potts transition which signals the effect due to frustration is always present. These results suggest that precursor phenomena in frustrated systems are due either to disorder and/or to frustration, giving a consistent interpretation also for the limiting cases of Ising spin glass and of Ising fully frustrated model, where also the Potts transition is vanishing. This interpretation could play a relevant role in glassy systems beyond the spin systems case.

The International Universities Walking Project: Development of a Framework for Workplace Intervention Using the Delphi Technique

Background: This paper aimed to use the Delphi technique to develop a consensus framework for a multinational, workplace walking intervention. Methods: Ideas were gathered and ranked from eight recognized and emerging experts in the fields of physical activity and health, from universities in Australia, Canada, England, the Netherlands, Northern Ireland, and Spain. Members of the panel were asked to consider the key characteristics of a successful campus walking intervention. Consensus was reached by an inductive, content analytic approach, conducted through an anonymous, three-round, e-mail process. Results: The resulting framework consisted of three interlinking themes defined as “design, implementation, and evaluation.” Top-ranked subitems in these themes included the need to generate research capacity (design), to respond to group needs through different walking approaches (implementation), and to undertake physical activity assessment (evaluation). Themes were set within an underpinning domain, referred to as the “institution” and sites are currently engaging with subitems in this domain, to provide sustainable interventions that reflect the practicalities of local contexts and needs. Conclusions: Findings provide a unique framework for designing, implementing, and evaluating walking projects in universities and highlight the value of adopting the Delphi technique for planning international, multisite health initiatives.

Automatic acquisition of Named Entities for Rule-Based Machine Translation

This paper proposes to enrich RBMTdictionaries with Named Entities(NEs) automatically acquired fromWikipedia. The method is appliedto the Apertium English-Spanishsystem and its performance comparedto that of Apertium with and withouthandtagged NEs. The system withautomatic NEs outperforms the onewithout NEs, while results vary whencompared to a system with handtaggedNEs (results are comparable forSpanish to English but slightly worstfor English to Spanish). Apart fromthat, adding automatic NEs contributesto decreasing the amount of unknownterms by more than 10%.