Local triple derivations on real C*-algebras and JB*-triples

We study when a local triple derivation on a real JB*-triple is a triple derivation. We find an example of a (real linear) local triple derivation on a rank-one Cartan factor of type I which is not a triple derivation. On the other hand, we find sufficient conditions on a real JB*-triple E to guarantee that every local triple derivation on E is a triple derivation

Reflexiones acerca de los modelos pedagógicos de la educación universitaria en la virtualidad

This article has the intention of redefining the importance of pedagogical models in Virtual Education are presented. To this end, a broad qualitative documentary approach was developed, with a descriptive approach based on a hermeneutic-historical method that allowed knowing the theoretical, epistemological and technological aspects associated with the current virtual university pedagogical models at first, to then contrast with the compilation of experiences in the international arena regarding these articulation processes and their relevance in training programs, focused on revealing new formulas that raise the excellence of Higher Education.En el presente artículo, tiene como intención resignificar la importancia de los modelos pedagógicos en la Educación Virtual. Para ello se desarrolló un amplio abordaje documental de corte cualitativo, con enfoque descriptivo basado en un método hermenéutico-histórico que permitió conocer los aspectos teóricos, epistemológicos y tecnológicos asociados a los actuales modelos pedagógicos virtuales universitarios en un primer momento, para luego contrastar con la recopilación de experiencias en el ámbito internacional frente a estos procesos de articulación y su relevancia en los programas de formación, enfocado en revelar nuevas fórmulas que eleven la excelencia de la Educación Superior

Utility and Residential Solar Resource Assessment and Modeling for Alaska’s Railbelt Transmission System

Research Poste

Modelling, simulation and experimental verification for renewable agents connected to a distorted utility grid using a Real-Time Digital Simulation Platform

The large number of Photovoltaic plants and its utilization as agents of a Distributed Generation Systems justified the increasing efforts towards the optimal design of the overall grid-connected System. In a Distributed Generation environment the low voltage 3-phase utility grid could be affected by some disturbances such as voltage unbalanced, variations of frequency and harmonics distortion and it is mandatory that the control algorithms used in the inverter can be able to maintain the power flow between the renewable agent and the low voltage 3-phase utility grid; in addition a unitary power factor must be attained. A Proportional-Resonant regulator is used to performance a current control with the output current of the inverter and a Multiple Second Order Generalized Integrator Frequency-Locked Loop (MSOGI-FLL) is used to detect the frequency of the low voltage 3-phase utility grid. Some low order harmonics are introduced in the low voltage 3-phase utility grid in order to see the effect of the harmonic compensator. In order to validate the model of the Photovoltaic Renewable agent, the synchronization algorithm and the inverter control algorithm, some simulations using MATLAB/SIMULINK from The MathWorks, Inc. are shown firstly, and secondly, some Real-Time Digital Simulation tests using a Real-Time Digital Simulation (RTDS) Platform are carried out.This work has been supported by a grant from La Fundación Séneca, Agencia de Ciencia y Tecnología de la Región de Murcia, as a part of the Project Ref.11948/PI/09, entitled “Design and construction of a hardware/software prototype for the synchronization and monitoring of renewable agents in a Distributed Generation System” (A. B. Rey-Boué), and a scholarship towards the PhD degree from the Universidad Politecnica de Cartagena with the financing of the Santander Bank (N. F. Guerrero-Rodríguez)

Adaptive-frequency Resonant Harmonic-Compensator structure for a 3-phase grid-connected photovoltaic system

In this paper, an adaptive-frequency Harmonic-Compensation structure for a Voltage Source Inverter used in a 3-phase grid-connected Photovoltaic system is presented. The main purpose is to show the frequency adaptation of the used control algorithm in order to improve the compensation of the low-order utility grid current harmonics when frequency variations occur, which can be seen as an outstanding feature when comparing to conventional non-adaptive Harmonic-Compensator structures, and can be used in any country regardless its nominal frequency and maintaining its Harmonic Compensation capability without making any change in the control algorithm. The frequency spectrum of the utility grid current is analyzed for three different scenarios: Proportional Resonant Controller without Harmonic Compensation, Proportional Resonant Controller with Harmonic Compensation, and adaptive-frequency Proportional Resonant Controller with Harmonic Compensation; a comparison with the normative of its individual and total harmonic amplitude distortions is carried out for the three situations. In order to validate the algorithms, some simulations using MATLAB/SIMULINK from The MathWorks, Inc. are shown firstly, and secondly, some real-time digital simulations are carried out.This work has been supported by a grant from La Fundación Séneca, Agencia de Ciencia y Tecnología de la Región de Murcia, Spain, as a part of the Project Ref.11948/PI/09, entitled “Design and construction of a hardware/software prototype for the synchronization and monitoring of renewable agents in a Distributed Generation System” (A. B. Rey-Boué), and a scholarship towards the PhD degree from the Universidad Politécnica de Cartagena, Spain, with the Santander Bank support (N. F. Guerrero-Rodríguez)

Les campagnes de fouille 2003 et 2004 à El Palao (Alcañiz, Teruel)

International audienceCompte rendu des campagnes de fouille de 2003 et 2004 sur l'oppidum de El Palao (Alcañiz, Teruel), occupé entre le premier âge du Fer et la fin du Ier siècle de notre ère

El principio interdisciplinar-curricular-virtual en el proceso de enseñanza-aprendizaje en la formación del profesional

This article aims to analyze the incorporation of digital technology in the professional training process related to the creation of new dynamics in the integration of academics, work and research. The analysis is carried out from the technological, organizational and training perspective proposed by the current models for the virtualization of substantive university processes in Cuba. Theoretical methods were used in order to carry out the analysis and synthesis of documentary and bibliographic reviews on the subject studied. From the development of the analysis carried out, a principle emerges that is called Interdisciplinary-Curricular-Virtual.Este artículo tiene como objetivo analizar la incorporación de la tecnología digital en el proceso de formación profesional relacionado con la creación de nuevas dinámicas en la integración de lo académico, lo laboral y lo investigativo. El análisis se realiza desde la perspectiva tecnológica, organizativa y formativa que proponen los actuales modelos para la virtualización de los procesos sustantivos universitarios en Cuba. Se emplearon métodos teóricos a fin de realizar el análisis y síntesis de revisiones documentales y bibliográficas sobre la temática estudiada. A partir del desarrollo del análisis realizado, emerge un principio al que se denomina Interdisciplinar-curricular-virtual

Anomalous diffusion of scaled Brownian tracers

A model for anomalous transport of tracer particles diffusing in complex media in two dimensions is proposed. The model takes into account the characteristics of persistent motion that active bath transfer to the tracer, thus the model proposed in here extends active Brownian motion, for which the stochastic dynamics of the orientation of the propelling force is described by scale Brownian motion (sBm), identified by a the time dependent diffusivity of the form $D_\beta\propto t^{\beta-1}$, $\beta>0$. If $\beta\neq1$, sBm is highly non-stationary and suitable to describe such a non-equilibrium dynamics induced by complex media. In this paper we provide analytical calculations and computer simulations to show that genuine anomalous diffusion emerge in the long-time regime, with a time scaling of the mean square displacement $t^{2-\beta}$, while ballistic transport $t^2$, characteristic of persistent motion, is found in the short-time one. An analysis of the time dependence of the kurtosis, and intermediate scattering function of the positions distribution, as well as the propulsion auto-correlation function, which defines the effective persistence time, are provided.Comment: 8 pages, 5 figure

A proof-of-concept superregenerative QPSK transceiver

In this paper we present a description and experimental verification of an HF-band proof-of-concept superregenerative transceiver for QPSK signals. We describe a simple implementation of an all-digital, FPGA-based, QPSK transmitter section. On the receiver side, the quench signal is generated in the same FPGA with a minimum of analog circuitry. As the main novelty, we present a simple synchronization scheme suitable for packetized transmissions.Peer ReviewedPostprint (author’s final draft

Anatomy of corpus callosum in prenatally malnourished rats

Indexación: Web of Science; ScieloThe effect of prenatal malnutrition on the anatomy of the corpus callosum was assessed in adult rats (45-52 days old). In the prenatally malnourished animals we observed a significant reduction of the corpus callosum total area, partial areas, and perimeter, as compared with normal animals. In addition, the splenium of corpus callosum (posterior fifth) showed a significant decrease of fiber diameters in the myelinated fibers without changing density. There was also a significant decrease in diameter and a significant increase in density of unmyelinated fibers. Measurements of perimeter's fractal dimensions from sagittal sections of the brain and corpus callosum did not show significant differences between malnourished and control animals. These findings indicate that cortico-cortical connections are vulnerable to the prenatal malnutrition, and suggest this may affect interhemispheric conduction velocity, particulary in visual connections (splenium).http://ref.scielo.org/nph4s