Simulating Spiking Neural P systems without delays using GPUs

We present in this paper our work regarding simulating a type of P system known as a spiking neural P system (SNP system) using graphics processing units (GPUs). GPUs, because of their architectural optimization for parallel computations, are well-suited for highly parallelizable problems. Due to the advent of general purpose GPU computing in recent years, GPUs are not limited to graphics and video processing alone, but include computationally intensive scientific and mathematical applications as well. Moreover P systems, including SNP systems, are inherently and maximally parallel computing models whose inspirations are taken from the functioning and dynamics of a living cell. In particular, SNP systems try to give a modest but formal representation of a special type of cell known as the neuron and their interactions with one another. The nature of SNP systems allowed their representation as matrices, which is a crucial step in simulating them on highly parallel devices such as GPUs. The highly parallel nature of SNP systems necessitate the use of hardware intended for parallel computations. The simulation algorithms, design considerations, and implementation are presented. Finally, simulation results, observations, and analyses using an SNP system that generates all numbers in $\mathbb N$ - {1} are discussed, as well as recommendations for future work.Comment: 19 pages in total, 4 figures, listings/algorithms, submitted at the 9th Brainstorming Week in Membrane Computing, University of Seville, Spai

Temporal disorder in up-down symmetric systems

The effect of temporal disorder on systems with up-down Z2 symmetry is studied. In particular, we analyze two well-known families of phase transitions: the Ising and the generalized voter universality classes, and scrutinize the consequences of placing them under fluctuating global conditions. We observe that variability of the control parameter induces in both classes "Temporal Griffiths Phases" (TGP). These recently-uncovered phases are analogous to standard Griffiths Phases appearing in systems with quenched spatial disorder, but where the roles of space and time are exchanged. TGPs are characterized by broad regions in parameter space in which (i) mean first-passage times scale algebraically with system size, and (ii) the system response (e.g. susceptibility) diverges. Our results confirm that TGPs are quite robust and ubiquitous in the presence of temporal disorder. Possible applications of our results to examples in ecology are discussed

El Mesolítico en Asturias: delimitación cronológica y espacial

Sin resume

MEMS Cantilever Biosensors Driven by Fringe Effect: Voltage-Amplitude Response of Parametric Resonance

This paper deals with voltage-amplitude response of fringing field/effect actuated micro-electromechanical system (MEMS) cantilever beam resonator biosensors at parametric resonance. The system consists of a flexible electrode (cantilever beam) and a fixed electrode (ground plate) in parallel, connected through an AC voltage source. The electrostatic force induced is due to the parallel-plate capacitance, which is directly related to the overlapping area of the two electrodes (Palmer’s Formula). In addition, fringing field electrostatic actuation must be accounted for. This is due to the bending of electric field lines from the ground plate to the top and side walls of the cantilever beam. In this study, the cantilever beam is actuated by the fringing field only. This is modelled by the following approach: the electrostatic force due to the parallel-plate capacitance is neglected due to a hole in the ground plate (removes overlapping area). With the frequency of the AC voltage near the natural frequency of the MEMS cantilever, the resonator will go into parametric resonance. The partial differential equation describing the dynamic behavior of the micro-beam resonator is nondimensionalized and a Reduced Order Model (ROM) is formulated. This is a one-mode of vibration model that is solved analytically using the Method of Multiple Scales (MMS). The voltage-amplitude response (bifurcation diagram) is projected. The force due to fringing actuation is expanded in Taylor Series and the terms up to the 3rd and 5th powers are kept (small terms due to small bookkeeping parameter). The method identified a zero-amplitude solution as well as two branches, one stable and one unstable, with two bifurcation points, subcritical and supercritical. In addition, a two-term reduced order model is developed and solved numerically to obtain steady-state solutions and validate the results. Finally, the equations from the two-term reduced order model are used in AUTO-07p (a continuation and bifurcation software for ODEs) to get a voltage response from the two-term ROM. The response is then compared to those that include the electrostatic force only as well as electrostatic and fringe together. The effect of damping, fringe, and detuning frequency on the voltage-amplitude response are also investigated

Efecto de la defoliación post-quema sobre el crecimiento de dos gramíneas nativas en el Caldenal, Argentina

El crecimiento en los pastizales naturales semiáridos puede ser afectado por la longitud de tiempo que el pastoreo es excluido durante el período de regeneración post-fuego. El objetivo de este trabajo a campo fue estudiar el efecto de la defoliación post-fuego en diferentes estados fenológicos: vegetativo (defoliación temprana) y elongación de entrenudos (defoliación tardía) sobre el crecimiento de Piptochaetium napostaense y Poa ligularis, dos gramíneas nativas perennes muy importantes en la región semiárida templada central de Argentina (Caldenal). En general, los tratamientos de defoliación post-quema no afectaron el número de hojas verdes en las macollas de P. napostaense. La defoliación temprana después del tratamiento de fuego generalmente redujo el número de hojas verdes en las macollas de P. ligularis con respecto a las plantas control. Contrariamente, la defoliación tardía usualmente incrementó el número de hojas verdes en las macollas de P. ligularis. Sin embargo, en ambos casos, muy pocas de las diferencias detectadas fueron significativas (p0,05) a aquellas de las plantas no defoliadas. Inmediatamente después de los tratamientos de defoliación temprana y tardía, las tasas de crecimiento relativas de la altura y la longitud verde total de las macollas de las plantas de ambas especies fueron reducidas (p0.05) than values on non-defoliated plants, respectively. Immediately after early- and late-season defoliation treatments, relative growth rates for tiller height and total green length were reduced (p<0.05) on plants of both species with respect to control plants. Our results suggest that a one-year-period without severe defoliations after fire would be at least necessary for not risking the persistence of these perennial grasses in the Caldenal community.Fil: Pelaez, Daniel Valerio. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; ArgentinaFil: Boo, Roberto Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; ArgentinaFil: Mayor, M. D.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; ArgentinaFil: Elia, Omar Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; ArgentinaFil: Martinez, S. A.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentin

Brecha digital y uso de las TIC en estudiantes universitarios

Tanto el acceso a las Tecnologías de la Información y la Comunicación (TIC) como la capacitación para usarlas y el buen uso de las mismas son elementos que intervienen de un modo u otro en toda la etapa universitaria de un estudiante. En esta comunicación se muestra, de modo preliminar, los resultados sobre el acceso a las TIC y los usos que hacen los estudiantes universitarios de los servicios Web 2.0, así como su presencia en las redes sociales. La población objeto de este estudio de caso son los estudiantes matriculados en primer curso del grado de Trabajo Social de la Universidad de Alicante en el curso 2013-2014. La metodología utilizada en esta investigación es cuantitativa mediante la aplicación de la técnica de la encuesta electrónica autoaplicada a través de Internet

Interaction between genes and lifestyle factors on obesity.

Obesity originates from a failure of the body-weight control systems, which may be affected by changing environmental influences. Basically, the obesity risk depends on two important mutually-interacting factors: (1) genetic variants (single-nucleotide polymorphisms, haplotypes); (2) exposure to environmental risks (diet, physical activity etc.). Common single-nucleotide polymorphisms at candidate genes for obesity may act as effect modifiers for environmental factors. More than 127 candidate genes for obesity have been reported and there is evidence to support the role of twenty-two genes in at least five different populations. Gene-environment interactions imply that the synergy between genotype and environment deviates from either the additive or multiplicative effect (the underlying model needs to be specified to appraise the nature of the interaction). Unravelling the details of these interactions is a complex task. Emphasis should be placed on the accuracy of the assessment methods for both genotype and lifestyle factors. Appropriate study design (sample size) is crucial in avoiding false positives and ensuring that studies have enough power to detect significant interactions, the ideal design being a nested case-control study within a cohort. A growing number of studies are examining the influence of gene-environmental interactions on obesity in either epidemiological observational or intervention studies. Positive evidence has been obtained for genes involved in adiposity, lipid metabolism or energy regulation such as PPARgamma2 (Pro12Ala), beta-adrenoceptor 2 (Gln27Glu) or uncoupling proteins 1, 2 and 3. Variants on other genes relating to appetite regulation such as melanocortin and leptin receptors have also been investigated. Examples of some recently-identified interactions are discussed

Trabajo social en España. De los recortes sociales a la arena pública

Los derechos humanos están sufriendo severos recortes con la excusa de que las políticas internacionales exigen ajustes económicos. Hay un cambio drástico de política. Las universidades y trabajadores sociales profesionales junto con las organizaciones civiles, están participando en el debate público y denunciando la calidad de estas políticas o su inexistencia cuando no las hay.La investigación que lleva a estos resultados ha recibido financiación por el People programme (Marie Curie Actions) del European Union's seventh framework programme Fp7/2007-2013 bajo el acuerdo Rea de subvención n.318938