Crossovers in the Two Dimensional Ising Spin Glass with ferromagnetic next-nearest-neighbor interactions

By means of extensive computer simulations we analyze in detail the two dimensional $\pm J$ Ising spin glass with ferromagnetic next-nearest-neighbor interactions. We found a crossover from ferromagnetic to ``spin glass'' like order both from numerical simulations and analytical arguments. We also present evidences of a second crossover from the ``spin glass'' behavior to a paramagnetic phase for the largest volume studied.Comment: 19 pages with 9 postscript figures also available at http://chimera.roma1.infn.it/index_papers_complex.html. Some changes in captions of figures 1 and

Study of the phase transition in the 3d Ising spin glass from out of equilibrium numerical simulations

Using the decay of the out equilibrium spin-spin correlation function we compute the equilibrium Edward-Anderson order parameter in the three dimensional binary Ising spin glass in the spin glass phase. We have checked that the Edward-Anderson order parameter computed from out of equilibrium numerical simulations follows with good precision the critical law as determined in experiments and in numerical studies at equilibrium. We have also studied the dependence of the order parameter with the lattice size. Finally we present a large time study of the scaling of the off-equilibrium fluctuation-dissipation relations.Comment: 14 pages, 7 Postscript figure

Relation of surface and underground waters in Chungará and Cotacotani lake districts, northern Chile: an isotopic study.

Lake Chungará and Cotacotani lake districts are surface water bodies located to the northwest of Lauca Basin in the northern Chilean Altiplano. Surface and underground waters show low to moderate saline content and an electrical conductivity in the range of 48.7 to 3090 μS/cm. The lakes are related to a system of aquifers on the nearby volcano flanks and debris avalanche deposits of Parinacota volcano. On the basis of δ18O and δD isotopic composition and its correlation with the chloride content in Chungará and Cotacotani lake, spring, and Chungará river waters it is demonstrated that: a. Lake Chungará's waters show vertical and horizontal homogeneous isotopic composition, which indicates a good mixture of waters in the lake; b. an important part of the Cotacotani lake recharge feeding come from Lake Chungará, that flows laterally as groundwater; c. the groundwater that feeds the springs of the area has its main recharge in the spring-summer (October-March) precipitation. The high content of tritium (3H) measured in spring waters of the area suggested a very recent recharge (last decades) of the aquifer system. The application of lumped parameter models to interpret the water residence time in the aquifer indicates that the piston flow model shows the best fit to the isotopic composition of Chungará-Cotacotani groundwater

Griffiths singularities in the two dimensional diluted Ising model

We study numerically the probability distribution of the Yang-Lee zeroes inside the Griffiths phase for the two dimensional site diluted Ising model and we check that the shape of this distribution is that predicted in previous analytical works. By studying the finite size scaling of the averaged smallest zero at the phase transition we extract, for two values of the dilution, the anomalous dimension, $\eta$, which agrees very well with the previous estimated values.Comment: 11 pages and 4 figures, some minor changes in Fig. 4, available at http://chimera.roma1.infn.it/index_papers_complex.htm

Introduction to Architecture: shaping the first contact

Introduction to Architecture is a subject taught in the School of Architecture of the University of A Coruña. It is intended to start the trainign of future professionals attending, from the the first course, to the tripple thoughtful, designed and constructive support of the architectural fact. With the Bologna Process, the subject became the initiatory place of the discipline, a sort of "first contact". The uniqueness of this fact, together with other circumstances, such as the recent introduction of teaching in English or conducting practices in a non-contact manner has led to the need of incorporating new technologies as means of control, mentoring and monitoring tasks and enhancement of teacher-student relationship inside the subject. Within this approach it has generated a central tool that serves as a gateway and communication of the subject: the website iala.udc.es.Introducción a la Arquitectura es una asignatura que se imparte en la Escuela Técnica Superior de Arquitectura de la Universidade da Coruña. En ella se pretende iniciar la formación del futuro profesional atendiendo, desde el primer curso, al triple soporte reflexivo, proyectivo y constructivo del hecho arquitectónico. Con el Proceso de Bolonia, la asignatura se convirtió en el lugar iniciático de la disciplina, en una suerte de «primer contacto». La singularidad de este hecho, sumado a otras circunstancias, como la reciente introducción de la docencia en inglés o la realización de las prácticas de manera no presencial, ha conducido a la necesidad de incorporar las nuevas tecnologías como modo de control, tutorización y seguimiento de tareas y potenciación de la relación profesor-alumno dentro de la asignatura. Dentro de este planteamiento se ha generado una herramienta nuclear que sirve de portal de acceso y comunicación de la asignatura: la web iala.udc.es

Self-consistent treatment of thermal effects in neutron-star post-mergers: observational implications for third-generation gravitational-wave detectors

We assess the impact of accurate, self-consistent modelling of thermal effects in neutron-star merger remnants in the context of third-generation gravitational-wave detectors. This is done through the usage, in Bayesian model selection experiments, of numerical-relativity simulations of binary neutron star (BNS) mergers modelled through: a) nuclear, finite-temperature (or ``tabulated'') equations of state (EoSs), and b) their simplifed piecewise (or ``hybrid'') representation. These cover four different EoSs, namely SLy4, DD2, HShen and LS220. Our analyses make direct use of the Newman-Penrose scalar $\psi_4$ outputted by numerical simulations. Considering a detector network formed by three Cosmic Explorers, we show that differences in the gravitational-wave emission predicted by the two models are detectable with a natural logarithmic Bayes Factor $\log{\cal{B}}\geq 5$ at average distances of $d_L \simeq 50$Mpc, reaching $d_L \simeq 100$Mpc for source inclinations $\iota \leq 0.8$, regardless of the EoS. This impact is most pronounced for the HShen EoS. For low inclinations, only the DD2 EoS prevents the detectability of such modelling differences at $d_L \simeq 150$Mpc. Our results suggest that the usage a self-consistent treatment of thermal effects is crucial for third-generation gravitational wave detectors.Comment: 9 pages, 3 Figure

Una Experiencia de iniciación al paralelismo en segundo curso del Grado de Ingeniería Informática

En este artículo se analiza una experiencia de introducción del paralelismo de forma temprana en el Grado de Ingeniería Informática. En la experiencia participan cuatro asignaturas de segundo curso, impartidas por tres departamentos distintos y con la colaboración de un centro de computación. En este curso se realiza la primera aproximación de los alumnos al paralelismo, y se pretende realizar un acercamiento coordinado y práctico a diferentes materias.SUMMARY -- This work presents an experience of early introduction to parallelism in the Degree on Computing Engineering. Four courses of the second year participate in the experience and also a computing centre. The courses are tought by three departments. In the second year the students are introduced to parallelism for the first time, and with our experience we intend to approach different topics of parallelism in a coordinated and practical way.Peer Reviewe