Comment on "Soliton ratchets induced by excitation of internal modes"

Very recently Willis et al. [Phys. Rev. E {\bf 69}, 056612 (2004)] have used a collective variable theory to explain the appearance of a nonzero energy current in an ac driven, damped sine-Gordon equation. In this comment, we prove rigorously that the time-averaged energy current in an ac driven nonlinear Klein-Gordon system is strictly zero.Comment: 3 pages, 1 figure, Submitted to Phys. Rev.

Nonlinear Stochastic Resonance with subthreshold rectangular pulses

We analyze the phenomenon of nonlinear stochastic resonance (SR) in noisy bistable systems driven by pulsed time periodic forces. The driving force contains, within each period, two pulses of equal constant amplitude and duration but opposite signs. Each pulse starts every half-period and its duration is varied. For subthreshold amplitudes, we study the dependence of the output signal-to-noise ratio (SNR) and the SR gain on the noise strength and the relative duration of the pulses. We find that the SR gains can reach values larger than unity, with maximum values showing a nonmonotonic dependence on the duration of the pulses.Comment: 7 pages, 2 figure

Effect of hypoxia on lung gene expression and proteomic profile: insights into the pulmonary surfactant response

Exposure of lung to hypoxia has been previously reported to be associated with significant alterations in the protein content of bronchoalveolar lavage (BAL) and lung tissue. In the present work we have used a proteomic approach to describe the changes in protein complement induced by moderate long-term hypoxia (rats exposed to 10% O2 for 72h) in BAL and lung tissue, with a special focus on the proteins associated with pulmonary surfactant, which could indicate adaptation of this system to limited oxygen availability. The analysis of the general proteomic profile indicates a hypoxia-induced increase in proteins associated with inflammation both in lavage and lung tissue. Analysis at mRNA and protein levels revealed no significant changes induced by hypoxia on the content in surfactant proteins or their apparent oligomeric state. In contrast, we detected a hypoxia-induced significant increase in the expression and accumulation of hemoglobin in lung tissue, at both mRNA and protein levels, as well as an accumulation of hemoglobin both in BAL and associated with surface-active membranes of the pulmonary surfactant complex. Evaluation of pulmonary surfactant surface activity from hypoxic rats showed no alterations in its spreading ability, ruling out inhibition by increased levels of serum or inflammatory proteins.Ministerio de Ciencia BIO2012-30733Ministerio de Ciencia CSD2007-00010Gobierno de la Comunidad de Madrid S2009MAT-1507National Institutes of Health NIH HL3478

Representar el movimiento / Presentar lo móvil

This article is proposed as an analysis of the artistic works which were interested in including movement representation or pointing to the attainment of kinetic art. Before incorporating the real movement in art works, there have been different attempts to represent it: by poses, instant grasp, or action narrative suggestion, and also by giving form to different movement stages. Thus, in this study we define two possible itineraries: “Representing the Movement” goes through the different approximations to movement representation from the pictorial and photographic practice, and “Presenting the Movable” does the same from the sculpture. We will travel through the path that covers the first trials to represent and fix something that moves in order to conquer the movable art itself, where the work becomes process and event, and it is developed, finally, into a time and space expanded action.This article is proposed as an analysis of the artistic works which were interested in including movement representation or pointing to the attainment of kinetic art. Before incorporating the real movement in art works, there have been different attempts to represent it: by poses, instant grasp, or action narrative suggestion, and also by giving form to different movement stages. Thus, in this study we define two possible itineraries: “Representing the Movement” goes through the different approximations to movement representation from the pictorial and photographic practice, and “Presenting the Movable” does the same from the sculpture. We will travel through the path that covers the first trials to represent and fix something that moves in order to conquer the movable art itself, where the work becomes process and event, and it is developed, finally, into a time and space expanded action

Torrents, barrancs i canalons, la xarxa de drenatge del Migjorn

Abstract not availabl

Face tracking and pose estimation with automatic three-dimensional model construction

A method for robustly tracking and estimating the face pose of a person using stereo vision is presented. The method is invariant to identity and does not require previous training. A face model is automatically initialised and constructed online: a fixed point distribution is superposed over the face when it is frontal to the cameras, and several appropriate points close to those locations are chosen for tracking. Using the stereo correspondence of the cameras, the three-dimensional (3D) coordinates of these points are extracted, and the 3D model is created. The 2D projections of the model points are tracked separately on the left and right images using SMAT. RANSAC and POSIT are used for 3D pose estimation. Head rotations up to ±45° are correctly estimated. The approach runs in real time. The purpose of this method is to serve as the basis of a driver monitoring system, and has been tested on sequences recorded in a moving car.Ministerio de Educación y CienciaComunidad de Madri

Gain in Stochastic Resonance: Precise Numerics versus Linear Response Theory beyond the Two-Mode Approximation

In the context of the phenomenon of Stochastic Resonance (SR) we study the correlation function, the signal-to-noise ratio (SNR) and the ratio of output over input SNR, i.e. the gain, which is associated to the nonlinear response of a bistable system driven by time-periodic forces and white Gaussian noise. These quantifiers for SR are evaluated using the techniques of Linear Response Theory (LRT) beyond the usually employed two-mode approximation scheme. We analytically demonstrate within such an extended LRT description that the gain can indeed not exceed unity. We implement an efficient algorithm, based on work by Greenside and Helfand (detailed in the Appendix), to integrate the driven Langevin equation over a wide range of parameter values. The predictions of LRT are carefully tested against the results obtained from numerical solutions of the corresponding Langevin equation over a wide range of parameter values. We further present an accurate procedure to evaluate the distinct contributions of the coherent and incoherent parts of the correlation function to the SNR and the gain. As a main result we show for subthreshold driving that both, the correlation function and the SNR can deviate substantially from the predictions of LRT and yet, the gain can be either larger or smaller than unity. In particular, we find that the gain can exceed unity in the strongly nonlinear regime which is characterized by weak noise and very slow multifrequency subthreshold input signals with a small duty cycle. This latter result is in agreement with recent analogue simulation results by Gingl et al. in Refs. [18, 19].Comment: 22 pages, 5 eps figures, submitted to PR

Evaluación, Calidad y Mejora Continua de los Servicios de Orientación en Educación Secundaria

Los servicios de Orientación educativa y profesional son un observatorio privilegiado del sistema educativo yun eslabón entre la calidad, la diversidad y la equidad. Por ello tienen la responsabilidad de evaluar sus resultados y mejorar sus procesos a través de acciones de evaluación, innovación e investigación. Las metodologías de investigación-acción pueden contribuir a estos objetivos a través de la participación de las personas implicadas y la elaboración conjunta de indicadores de evaluación apropiados para los servicios de orientación en Educación Secundaria. Todo ello permitirá mejorar la calidad de estos servicios dedicando más tiempo a lo que más valor apora a estos servicios, es decir, al trato personal, la realción de confianza y la personalización de la educación

On the incorporation of interval-valued fuzzy sets into the Bousi-Prolog system: declarative semantics, implementation and applications

In this paper we analyse the benefits of incorporating interval-valued fuzzy sets into the Bousi-Prolog system. A syntax, declarative semantics and im- plementation for this extension is presented and formalised. We show, by using potential applications, that fuzzy logic programming frameworks enhanced with them can correctly work together with lexical resources and ontologies in order to improve their capabilities for knowledge representation and reasoning