Semiempirical Modeling of Reset Transitions in Unipolar Resistive-Switching based Memristors

We have measured the transition process from the high to low resistivity states, i.e., the reset process of resistive switching based memristors based on Ni/HfO2/Si-n+ structures, and have also developed an analytical model for their electrical characteristics. When the characteristic curves are plotted in the current-voltage (I-V) domain a high variability is observed. In spite of that, when the same curves are plotted in the charge-flux domain (Q-phi), they can be described by a simple model containing only three parameters: the charge (Qrst) and the flux (rst) at the reset point, and an exponent, n, relating the charge and the flux before the reset transition. The three parameters can be easily extracted from the Q-phi plots. There is a strong correlation between these three parameters, the origin of which is still under study

Contribuição para a caracterização da recolha comercial de macrofungos comestíveis no distrito de Bragança, Portugal

Com este trabalho pretendeu-se caracterizar a actividade de recolha de cogumelos comestíveis no distrito de Bragança relativamente a espécies e quantidades, habitats, formas de recolha e transporte e valor comercial. Apurou-se que as recolhas incidem principalmente sobre Amanita caesarea, Boletus pinicola, B. edulis, B. aereus, Lactarius deliciosus, Tricholoma equestre, T. georgii, e T. portentosum. As quantidades recolhidas são geralmente inferiores a 5 kg/colector/dia observando-se no global um maior peso das recolhas superiores a 5 kg/colector/dia. As espécies são recolhidas em ecossistemas florestais de e em sistemas agro-florestais. A recolha de cogumelos não constitui a actividade principal dos colectores

Prosopis, Retama monosperma. Phragmites y Arundo donax en cosechas sucesivas a uno y dos años de crecimiento, para la elaboración de pasta celulósica y papel

Se evalúa la aptitud de ciertas especies regeneradoras de terrenos degradados: Prosopis (variedades: alba y juliflora),Retama monosperma, Phragmites y Arundo donax, para la fabricación de pastas celulósicas y hojas de papel, mediante un proceso de pasteo organosolv alcalino. Se caracterizan y comparan las materias primas, pastas celulósicas y hojas de papel, para cosechas de un año (más rebrotes de un año de edad, después de haberlas cortado al año) y dos años de crecimiento. Las especies Retama monosperma, Phragmites y Arundodonax muestran potencialidad para su aprovechamientoindustrial, en cosechas de corta rotación, para la obtenciónde pastas celulósicas y papel. Los números kappa de las pastas de 2º año están entre 10,3 y 12,6, con números de tracción entre 13,7 y 20,9 kNm·kg–1 en las pastas sin refinar. Sin embargo la explotación industrial de las dos variedades de Prosopis precisaría su adecuación a tiempos de explotación más largos, que los estudiados en este trabajo

Atmospheric Neutrino Oscillations and New Physics

We study the robustness of the determination of the neutrino masses and mixing from the analysis of atmospheric and K2K data under the presence of different forms of phenomenologically allowed new physics in the nu_mu--nu_tau sector. We focus on vector and tensor-like new physics interactions which allow us to treat, in a model independent way, effects due to the violation of the equivalence principle, violations of the Lorentz invariance both CPT conserving and CPT violating, non-universal couplings to a torsion field and non-standard neutrino interactions with matter. We perform a global analysis of the full atmospheric data from SKI together with long baseline K2K data in the presence of nu_mu -> nu_tau transitions driven by neutrino masses and mixing together with sub-dominant effects due to these forms of new physics. We show that within the present degree of experimental precision, the extracted values of masses and mixing are robust under those effects and we derive the upper bounds on the possible strength of these new interactions in the nu_mu--nu_tau sector.Comment: 22 pages, LaTeX file using RevTEX4, 5 figures and 4 tables include

Desarrollo de un chip de DNA para la detección de dianas génicas bacterianas de interés en el campo de la acuicultura

La adquisición bacteriana de multiresistencias frente a antimicrobianos es un fenómeno cada vez más preocupante, con gran repercusión para la salud pública, pero también con impacto en sectores de la producción animal, como es el caso particular de la acuicultura. Entre los años 2010-2012, como objetivo de un Proyecto de Investigación Italiano (Progetti d’interesse Nazionale, PRIN), se realizaron diferentes campañas de muestreo a lo largo de la costa del mar Adriático, en centros dedicados a la acuicultura y áreas costeras, estudiando la incidencia de bacterias multiresistentes, así como de los elementos genéticos móviles responsables de su adquisición, desarrollando además una herramienta biotecnológica que agiliza este tipo de estudios permitiendo detectar 164 dianas génicas en un único soporte. Se obtuvo una colección de 1274 aislados bacterianos, a partir de muestras de agua, sedimento y biofilm, resistentes a las distintas combinaciones de antibióticos utilizados según la legislación italiana. Del total, 105 (8,25%) aislados resultaron ser multiresistentes, detectándose en el 13,59% el integrón de clase I, en el 14,56% el plásmido pAb5s9, en el 5,82% el elemento SXT/R391, y en el 15,52% diferentes combinaciones de estos elementos genéticos. Basándonos en estos resultados, se ha desarrollado y validado un chip de DNA que permite detectar en un mismo soporte, genes que codifican para determinantes de resistencia a antimicrobianos, elementos genéticos móviles (MGE), genes para la detección de especies bacterianas patógenas con repercusión en acuicultura y para la salud del hombre, e indicadores de contaminación fecal.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

An Agent-Based Model of Collective Emotions in Online Communities

We develop a agent-based framework to model the emergence of collective emotions, which is applied to online communities. Agents individual emotions are described by their valence and arousal. Using the concept of Brownian agents, these variables change according to a stochastic dynamics, which also considers the feedback from online communication. Agents generate emotional information, which is stored and distributed in a field modeling the online medium. This field affects the emotional states of agents in a non-linear manner. We derive conditions for the emergence of collective emotions, observable in a bimodal valence distribution. Dependent on a saturated or a superlinear feedback between the information field and the agent's arousal, we further identify scenarios where collective emotions only appear once or in a repeated manner. The analytical results are illustrated by agent-based computer simulations. Our framework provides testable hypotheses about the emergence of collective emotions, which can be verified by data from online communities.Comment: European Physical Journal B (in press), version 2 with extended introduction, clarification

Quantum states and specific heat of low-density He gas adsorbed within the carbon nanotube interstitial channels: Band structure effects and potential dependence

We calculate the energy-band structure of a He atom trapped within the interstitial channel between close-packed nanotubes within a bundle and its influence on the specific heat of the adsorbed gas. A robust prediction of our calculations is that the contribution of the low-density adsorbed gas to the specific heat of the nanotube material shows pronounced nonmonotonic variations with temperature. These variations are shown to be closely related to the band gaps in the adsorbate density of states

Status of a hybrid three-neutrino interpretation of neutrino data

We reanalyze the non-standard interaction (NSI) solutions to the solar neutrino problem in the light of the latest solar, atmospheric and reactor neutrino data. We show that such solutions, although preferred by the solar data and consistent with the oscillation description of the atmospheric neutrino data, are ruled out by the first results of the KamLAND reactor experiment, at more than 3_sigma.Comment: 19 pages, LaTeX file using Elsart, 2 tables and 4 figures included. This version updates the one published in Nucl.Phys.B629:479-490,2002 by including the new KamLAND dat

Effects of new physics in neutrino oscillations in matter

A new flavor changing electron neutrino interaction with matter would always dominate the nu_e oscillation probability at sufficiently high neutrino energies. Being suppressed by theta_{13}, the energy scale at which the new effect starts to be relevant may be within the reach of realistic experiments, where the peculiar dependence of the signal with energy could give rise to a clear signature in the nu_e --> nu_tau channel. The latter could be observed by means of a coarse large magnetized detector by exploiting tau --> mu decays. We discuss the possibility of identifying or constraining such effects with a high energy neutrino factory. We also comment on the model independent limits on them.Comment: 11 pages, 5 figure