q-State Potts model metastability study using optimized GPU-based Monte Carlo algorithms

We implemented a GPU based parallel code to perform Monte Carlo simulations of the two dimensional q-state Potts model. The algorithm is based on a checkerboard update scheme and assigns independent random numbers generators to each thread. The implementation allows to simulate systems up to ~10^9 spins with an average time per spin flip of 0.147ns on the fastest GPU card tested, representing a speedup up to 155x, compared with an optimized serial code running on a high-end CPU. The possibility of performing high speed simulations at large enough system sizes allowed us to provide a positive numerical evidence about the existence of metastability on very large systems based on Binder's criterion, namely, on the existence or not of specific heat singularities at spinodal temperatures different of the transition one.Comment: 30 pages, 7 figures. Accepted in Computer Physics Communications. code available at: http://www.famaf.unc.edu.ar/grupos/GPGPU/Potts/CUDAPotts.htm

Long term ordering kinetics of the two dimensional q-state Potts model

We studied the non-equilibrium dynamics of the q-state Potts model in the square lattice, after a quench to sub-critical temperatures. By means of a continuous time Monte Carlo algorithm (non-conserved order parameter dynamics) we analyzed the long term behavior of the energy and relaxation time for a wide range of quench temperatures and system sizes. For q>4 we found the existence of different dynamical regimes, according to quench temperature range. At low (but finite) temperatures and very long times the Lifshitz-Allen-Cahn domain growth behavior is interrupted with finite probability when the system stuck in highly symmetric non-equilibrium metastable states, which induce activation in the domain growth, in agreement with early predictions of Lifshitz [JETP 42, 1354 (1962)]. Moreover, if the temperature is very low, the system always gets stuck at short times in a highly disordered metastable states with finite life time, which have been recently identified as glassy states. The finite size scaling properties of the different relaxation times involved, as well as their temperature dependency are analyzed in detail.Comment: 10 pages, 17 figure

First record of Mylodon Darwini Owen (xenarthra, tardigrada, mylodontidae) from Arroyo Feliciano formation (late pleistocene), Entre Rios, Argentina

In this contribution a new record of M. darwini Owen, based on an incomplete skull (MRHU-1) recovered from the Arroyo Feliciano Formation (late Pleistocene) on the Gualeguay River cliffs, nearly the city of Urdinarrain, is presented. Although the characteristic nasal arch of Mylodon darwini is not preserved at all, the morphology of the preserved portion and the presence of four maxillary lobated alveoli for the molariforms justify its assignment to this species. Based on its geographic and chronologic record, M. darwini has been associated to open environments with semiarid and cold climate (e.g. Pleistocene Pampean region and Patagonia of Argentina and Chile) as warm and humid climate (e.g. El Palmar Formation, late Pleistocene, Entre Ríos Province; late Pleistocene Arroyo Chuí, Brazil). The fi nd of M. darwini in the Arroyo Feliciano Formation is important given that it corresponds to the fi rst record of the species for the Formation and the second one for the province. Besides, the presence of M. darwini Arroyo Feliciano Formation corroborates the hypothesis that the genus inhabited in warm and humid climates.Neste trabalho damos a conhecer um novo registro de Mylodon darwini Owen, representado por um crânio incompleto (MRHU-1) encontrado nos sedimentos da Formação Arroyo Feliciano (Pleistoceno fi nal) afl orante nas barrancas do rio Gualeguay, nas proximidades da localidade de Urdinarrain, Província de Entre Ríos, Argentina. Apesar do característico arco nasal de M. darwini não estar totalmente preservado no exemplar, a morfologia da porção preservada do rostro e a presença de quatro alvéolos superiores do tipo molariforme lobulado, justifi cam sua atribuição a esta espécie. Com base no seu registro, tanto geográfi co quanto cronológico, M. darwini tem sido associado a ambientes abertos com climas semiáridos e frios (e.g. Pleistoceno da Região Pampeana e Patagônia da Argentina e do Chile) e a quentes e úmidos (e.g. Formação El Palmar, Pleistoceno fi nal, Provincia de Entre Ríos; Pleistoceno superior de Arroio Chuí, Brasil). A presença de M. darwini na Formação Arroyo Feliciano é importante, pois corresponde ao primeiro registro da espécie para esta formação e o segundo para a província. Além disso, a presença de M. darwini na Formação Arroyo Feliciano corrobora com a hipótese de que o gênero habitava ambientes de clima quente e úmido.Fil: Favotti, Sergio Emmanuel. Provincia de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Universidad Autónoma de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción; ArgentinaFil: Ferrero, Brenda Soledad. Provincia de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Universidad Autónoma de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción; ArgentinaFil: Brandoni, Diego. Provincia de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Universidad Autónoma de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción; Argentin

Short-time dynamics of finite-size mean-field systems

We study the short-time dynamics of a mean-field model with non-conserved order parameter (Curie-Weiss with Glauber dynamics) by solving the associated Fokker-Planck equation. We obtain closed-form expressions for the first moments of the order parameter, near to both the critical and spinodal points, starting from different initial conditions. This allows us to confirm the validity of the short-time dynamical scaling hypothesis in both cases. Although the procedure is illustrated for a particular mean-field model, our results can be straightforwardly extended to generic models with a single order parameter.Comment: accepted for publication in JSTA

Influencia de las TIC en la enseñanza del profesorado y en el aprendizaje del alumnado de educación primaria en la zona de los montes orientales de granada

[ES]El objetivo de esta tesis se centra en dos aspectos. Por un lado concretar las necesidades de formación TIC del profesorado de tercer ciclo de Primaria en la zona de los Montes Orientales de Granada, aportando información sobre tres aspectos esenciales: su formación TIC; la incorporación de éstas en el currículum; así como la contribución de los CEP en este cambio metodológico. En segundo lugar ofrece los resultados sobre el uso que de las TIC hace del alumnado de tercer ciclo; el impacto y repercusión que estos recursos están teniendo sobre los alumnos/as en las áreas instrumentales y de cómo se están llevando a la práctica dichas metodologías. Así, se pueden establecer conclusiones sobre la adecuada implementación de estos recursos en los currículum. Finalmente se establecen retos y perspectivas de mejora que fomente el desarrollo de estos recursos en el aula de Educación Primaria que favorezcan adoptar estos enfoques metodológicos.[EN]My main objective in this thesis is focused on two issues. First, I try to find out the needs of improvement in the use of new technologies among 3rd grade teachers in Montes Orientales de Granada area. To get this, I give some information about three essential aspects: their previous formation in new technologies; how these new technologies are adapted to the new curriculum and also how Teacher Formation Centers (CEP) have influenced on this methodological change. Secondly, I provide some results about the use of new technologies among 3rd grade students; about the influence of these resources on students of instrumental subjects and also about how new technologies are being put into practice. All this helps to set the conclusions on the implementation of these resources in forthcoming curriculums.Finally, I propose new challenges and points of view to promote the use of new technologies in Primary Education so as to ease a total acceptance of these methodogical approaches.Tesis Univ. Jaén. Departamento de Pedagogía, leída el 30 de mayo de 201

Preparación de compuestos poliaromáticos con capacidad para establecer interacciones supramoleculares con fulerenos

El fulereno es el más conocido de los compuestos poliaromáticos no planos, desde su descubrimiento se han publicado infinidad de publicaciones, entre las que se encuentran las interacciones supramoleculares. En esta memoria se han desarrollado porfirinas meso­ tetrapoliaromaticas con unidades fenantreno, pireno y coranuleno con la orientación adecuada para establecer interacciones supramoleculares con fulerenos y dicha interacción se ha evaluado mediante experimentos de RMN y UV-Vis.Departamento de Química Física y Química InorgánicaMáster en Química Sintética e Industria

Upgrading evolutionary algorithms through multiplicity for multiobjective optimization in job shop scheduling problems

In previous works the ability of CPS-MCPC (an evolutionary, co-operative, population search method with multiple crossovers per couple) to build well delineated Pareto fronts in diverse multiobjective optimization problems (MOOPs) was demonstrated. To test the potential of the novel method when dealing with the Job Shop Scheduling Problem (JSSP), regular and non-regular objectives functions were chosen. They were the makespan and the mean absolute deviation (of job completion times from a common due date, an earliness/tardiness related problem). Diverse representations such as priority list representation (PLR), job-based representation (JBR) and operation-based representation (OBR) among others were implemented and tested. The latter showed to be the best one. As a good parameter setting can enhance the behaviour of an evolutionary algorithm distinct parameters combinations were implemented and their influence studied. Multiple crossovers on multiple parents (MCMP), a powerful multirecombination method showed some enhancement in single objective optimization when compared with MCPC. This paper shows the influence of different recombination schemes when building the Pareto front under OBR and using the best parameter settings determined in previous works on a set of demonstrative Lawrence´s instances. Details of implementation and results are discussed.Eje: Sistemas inteligentesRed de Universidades con Carreras en Informática (RedUNCI

Space Vector Taylor–Fourier Models for Synchrophasor, Frequency, and ROCOF Measurements in Three-Phase Systems

Taylor-Fourier (TF) filters represent a powerful tool to design phasor measurement unit (PMU) algorithms able to estimate synchrophasor, frequency, and rate of change of frequency (ROCOF). The resulting techniques are based on dynamic representations of the synchrophasor, and hence, they are particularly suitable to track the evolution of its parameters during time-varying conditions. Electrical quantities in power systems are typically three-phase and weakly unbalanced, but most PMU measurement techniques are developed by considering them as a set of three single-phase signals; on the contrary, this peculiarity can be favorably exploited to improve accuracy and reduce the computational cost. In this respect, this paper proposes to directly perform the TF expansion of the space vector (SV) samples obtained from three-phase measurements. A new paradigm allows to independently estimate positive and negative sequence synchrophasors along with system frequency and ROCOF, leveraging the three-phase characteristics. The performance of the proposed technique is assessed by using test signals inspired by the standard IEEE C37.118.1-2011, including noise as well as magnitude and phase unbalance. Achieved results highlight the flexibility of the enhanced SV-based approach, which is capable to combine excellent dynamic performance together with an accurate estimation of both positive and negative sequence components