Enhanced error estimator based on a nearly equilibrated moving least squares recovery technique for FEM and XFEM

In this paper a new technique aimed to obtain accurate estimates of the error in energy norm using a moving least squares (MLS) recovery-based procedure is presented. We explore the capabilities of a recovery technique based on an enhanced MLS fitting, which directly provides continuous interpolated fields, to obtain estimates of the error in energy norm as an alternative to the superconvergent patch recovery (SPR). Boundary equilibrium is enforced using a nearest point approach that modifies the MLS functional. Lagrange multipliers are used to impose a nearly exact satisfaction of the internal equilibrium equation. The numerical results show the high accuracy of the proposed error estimator

A novel wavelet-based filtering strategy to remove powerline interference from electrocardiograms with atrial fibrillation

This is an author-created, un-copyedited versíon of an article published in Physiological Measurement. IOP Publishing Ltd is not responsíble for any errors or omissíons in this versíon of the manuscript or any versíon derived from it. The Versíon of Record is available online at http://doi.org/10.1088/1361-6579/aae8b1[EN] Objective: The electrocardiogram (ECG) is currently the most widely used recording to diagnose cardiac disorders, including the most common supraventricular arrhythmia, such as atrial fibrillation (AF). However, different types of electrical disturbances, in which power-line interference (PLI) is a major problem, can mask and distort the original ECG morphology. This is a significant issue in the context of AF, because accurate characterization of fibrillatory waves (f-waves) is unavoidably required to improve current knowledge about its mechanisms. This work introduces a new algorithm able to reduce high levels of PLI and preserve, simultaneously, the original ECG morphology. Approach: The method is based on stationary wavelet transform shrinking and makes use of a new thresholding function designed to work successfully in a wide variety of scenarios. In fact, it has been validated in a general context with 48 ECG recordings obtained from pathological and non-pathological conditions, as well as in the particular context of AF, where 380 synthesized and 20 long-term real ECG recordings were analyzed. Main results: In both situations, the algorithm has reported a notably better performance than common methods designed for the same purpose. Moreover, its effectiveness has proven to be optimal for dealing with ECG recordings affected by AF, sincef-waves remained almost intact after removing very high levels of noise. Significance: The proposed algorithm may facilitate a reliable characterization of thef-waves, preventing them from not being masked by the PLI nor distorted by an unsuitable filtering applied to ECG recordings with AF.Research supported by grants DPI2017-83952-C3 MINECO/AEI/FEDER, UE and SBPLY/17/180501/000411 from Junta de Comunidades de Castilla-La Mancha.García, M.; Martínez, M.; Ródenas, J.; Rieta, JJ.; Alcaraz, R. (2018). A novel wavelet-based filtering strategy to remove powerline interference from electrocardiograms with atrial fibrillation. Physiological Measurement. 39(11):1-15. https://doi.org/10.1088/1361-6579/aae8b1S115391

Quantum groups and deformed special relativity

The structure and properties of possible $q$-Minkowski spaces is discussed, and the corresponding non-commutative differential calculi are developed in detail and compared with already existing proposals. This is done by stressing its covariance properties as described by appropriate reflection equations. Some isomorphisms among the space-time and derivative algebras are demonstrated, and their representations are described briefly. Finally, some physical consequences and open problems are discussed

Evolución tipológica de cubiertas ventiladas ‘a la catalana’ en la obra de Antonio Bonet

In this study we analyse the evolution of a series of buildings designed by Antonio Bonet that share the same vernacular construction typology: the ‘Catalan’ ventilated roofs. We try to demonstrate the investigatory method of Bonet, who does not regard form in his projects as a purely personal invention. The pattern may mutate or transgress for different reasons, whether to adapt to the technological advances of a building system or to programmatic, topographic or climatic changes. On the basis of the information in the architect’s archive, we create and present new graphical documentation through the redrawing of his works in order to organise archive material that is difficult to access due its dispersal, different scales and different formats. The present study will enable anyone interested to obtain basic data on each building.En este trabajo analizamos la evolución de una serie de edificios diseñados por Antonio Bonet que comparten una tipología constructiva de origen vernáculo: la cubierta ventilada ‘a la catalana’. Trataremos de demostrar el método investigador de Bonet quien no concibe la forma en sus proyectos como una pura invención personal. El patrón puede mutar o transgredirse por diferentes motivos, ya sea para adaptarse al avance tecnológico de un sistema constructivo, ya sea por adaptaciones topográficas, climáticas o programáticas. A partir de la información del archivo del arquitecto, elaboramos y presentamos nueva documentación gráfica, a través del redibujado de las obras, con el objetivo de ordenar un material de archivo de difícil acceso por diferentes motivos: dispersión, diferencia de escalas, diferentes soportes gráficos. Con este trabajo, cualquier interesado puede obtener los datos básicos de cada edificio

Dynamics of the solutions of the water hammer equations

NOTICE: this is the author’s version of a work that was accepted for publication in Topology and its Applications. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Topology and its Applications, [Volume 203, 15 April 2016, Pages 67-83] DOI10.1016/j.topol.2015.12.076¨[EN] In this note we provide a representation of the solution using an operator theoretical approach based on the theory of C-0-semigroups and cosine operator functions, when considering this phenomenon on a compressible fluid along an infinite pipe. We provide an integro-differential equation that represents this phenomenon and it only involves the discharge. In addition, the representation of the solution in terms of a specific C-0-semigroup lets us show that hypercyclicity and the topologically mixing property can occur when considering this phenomenon on certain weighted spaces of integrable and continuous functions on the real line. (C) 2016 Elsevier B.V. All rights reserved.The first and third authors are supported by MEC Projects MTM2010-14909 and MTM2013-47093-P. The first author is also supported by Programa de Investigación y Desarrollo de la UPV, Ref. SP20120700. The second author is partially supported by CONICYT, under Fondecyt Grant number 1140258.Conejero, JA.; Lizama, C.; Ródenas Escribá, FDA. (2016). Dynamics of the solutions of the water hammer equations. Topology and its Applications. 203:67-83. https://doi.org/10.1016/j.topol.2015.12.076S678320

Catheter Ablation Outcome Prediction With Advanced Time-Frequency Features of the Fibrillatory Waves From Patients in Persistent Atrial Fibrillation

[EN] Although catheter ablation (CA) is still the first-line treatment for persistent atrial fibrillation (AF) patients, its limited long-term success rate has motivated clinical interest in preoperative prediction on the procedure¿s outcome to provide optimized patient selection, limit repeated procedures, hospitalization rates, and treatment costs. To this respect, dominant frequency (DF) and amplitude of fibrillatory waves (f-waves) reflected on the ECG have provided promising results. Hence this work explores the ability of a novel set of frequency and amplitud f-waves features, such as spectral entropy (SE), spectral flatness measure (SFM), and amplitud spectrum area (AMSA), along with DF and normalized f-wave amplitude (NFWA), to improve CA outcome prediction. Despite all single indices reported statistically significant differences between patients who relapsed to AF and those who maintained sinus rhythm after a follow-up of 9 months for 204 6 s-length ECG intervals extracted from 51 persistent AF patients, they obtained a limited discriminant ability ranging between 55 and 62%, which was overcome by 15¿23% when NFWA, SE and AMSA were combined. Consequently, this combination of frequency and amplitude features of the fwaves seems to provide new insights about the atrial substrate remodeling, which could be helpful in improving preoperative CA outcome prediction.This research has been supported by grants DPI201783952-C3 from MINECO/AEI/FEDER EU, SBPLY/17/180501/000411 from Junta de Comunidades de Castilla-la Mancha and AICO/2019/036 from Generalitat Valenciana. Moreover, Pilar Escribano holds a graduate research scholarship from University of Castilla-La ManchaEscribano, P.; Ródenas, J.; Arias, MA.; Langley, P.; Rieta, JJ.; Alcaraz, R. (2020). Catheter Ablation Outcome Prediction With Advanced Time-Frequency Features of the Fibrillatory Waves From Patients in Persistent Atrial Fibrillation. IEEE. 1-4. https://doi.org/10.22489/CinC.2020.396S1

Certification of projection-based reduced order modelling in computational homogenisation by the constitutive relation error

SUMMARY: In this paper, we propose upper and lower error bounding techniques for reduced order modelling applied to the computational homogenisation of random composites. The upper bound relies on the construction of a reduced model for the stress field. Upon ensuring that the reduced stress satisfies the equilibrium in the finite element sense, the desired bounding property is obtained. The lower bound is obtained by defining a hierarchical enriched reduced model for the displacement. We show that the sharpness of both error estimates can be seamlessly controlled by adapting the parameters of the corresponding reduced order model. © 2013 John Wiley & Sons, Ltd

Atmospheric isoprene ozonolysis: impacts of stabilised Criegee intermediate reactions with SO₂, H₂O and dimethyl sulfide

Isoprene is the dominant global biogenic volatile organic compound (VOC) emission. Reactions of isoprene with ozone are known to form stabilised Criegee intermediates (SCIs), which have recently been shown to be potentially important oxidants for SO2 and NO2 in the atmosphere; however the significance of this chemistry for SO2 processing (affecting sulfate aerosol) and NO2 processing (affecting NOx levels) depends critically upon the fate of the SCIs with respect to reaction with water and decomposition. Here, we have investigated the removal of SO2 in the presence of isoprene and ozone, as a function of humidity, under atmospheric boundary layer conditions. The SO2 removal displays a clear dependence on relative humidity, confirming a significant reaction for isoprene-derived SCIs with H2O. Under excess SO2 conditions, the total isoprene ozonolysis SCI yield was calculated to be 0.56 (+/-0.03). The observed SO2 removal kinetics are consistent with a relative rate constant, k (SCI + H2O) = k (SCI + SO2), of 3.1 (+/-0.5) x 10(-5) for isoprene-derived SCIs. The relative rate constant for k (SCI decomposition) = k (SCI + SO2) is 3.0 (+/-3.2) x 10(11) cm(-3). Uncertainties are +/-2 sigma and represent combined systematic and precision components. These kinetic parameters are based on the simplification that a single SCI species is formed in isoprene ozonolysis, an approximation which describes the results well across the full range of experimental conditions. Our data indicate that isoprenederived SCIs are unlikely to make a substantial contribution to gas-phase SO2 oxidation in the troposphere. We also present results from an analogous set of experiments, which show a clear dependence of SO2 removal in the isopreneozone system as a function of dimethyl sulfide concentration. We propose that this behaviour arises from a rapid reaction between isoprene-derived SCIs and dimethyl sulfide (DMS); the observed SO2 removal kinetics are consistent with a relative rate constant, k (SCI + DMS) = k (SCI + SO2), of 3.5 (+/-1.8). This result suggests that SCIs may contribute to the oxidation of DMS in the atmosphere and that this process could therefore influence new particle formation in regions impacted by emissions of unsaturated hydrocarbons and DMS

Effects of ketosis on cocaine-induced reinstatement in male mice;

In recent years, the benefits of the ketogenic diet (KD) on different psychiatric disorders have been gaining attention, but the substance abuse field is still unexplored. Some studies have reported that palatable food can modulate the rewarding effects of cocaine, but the negative metabolic consequences rule out the recommendation of using it as a complementary treatment. Thus, the main aim of this study was to evaluate the effects of the KD on cocaine conditioned place preference (CPP) during acquisition, extinction, and reinstatement. 41 OF1 male mice were employed to assess the effects of the KD on a 10 mg/kg cocaine-induced CPP. Animals were divided into three groups: SD, KD, and KD after the Post-Conditioning test. The results revealed that, while access to the KD did not block CPP acquisition, it did significantly reduce the number of sessions required to extinguish the drug-associated memories and it blocked the priming-induced reinstatement. © 2022 The Author(s