HTS nonlinearities in microwave disk resonators

This article describes a procedure for the calculation of the intermodulation behavior of the TM010 mode in high temperature superconducting (HTS) disk resonators from a description of the local HTS nonlinearities. Successful cross-checks are performed by comparing the theoretical results with experimental measurements and simulations based on the multiport harmonic balance algorithm for a specific model of HTS nonlinearity. The application of this procedure to the determination of nonlinear material parameters from disk resonator measurements is illustrated and compared to theoretical predictions.Peer Reviewe

Nonlinear RF spurious in a cylindrical cavity with superconducting endplates

We have developed a method to calculate the distribution of fundamental and spurious fields in a metallic cylindrical cavity with superconducting endplates in which signals at two different frequencies are injected. The nonlinearity in the superconductor produces the typical intermodulation effects if the frequencies of the injected signals are sufficiently close to each other and near a resonant mode. Our method uses harmonic balance to match the fields in the cavity with the currents on the endplates. The method can be used for a variety of nonlinear models of the superconducting endplate, and could be the base for a nondestructive procedure to extract the nonlinear parameters of an HTS sample from RF measurements. Our analysis is restricted to the TE011 mode, but the method can be applied to any propagating mode in the cylindrical cavity. Closed-form equations for the case of square-law nonlinearities in the superconductor are derived and used to check the validity of the harmonic balance calculation.Peer Reviewe

Harmonic balance algorithms for the nonlinear simulation of HTS devices

This paper describes the application of Harmonic Balance algorithms to predict nonlinear effects in planar High Temperature Superconductors (HTS) microwave circuits. The resulting algorithms are fast and efficient and can be used both for the characterization of the nonlinearities in the HTS material, and for the prediction of the behavior of an HTS circuit given the parameters of these nonlinearities (such as a dependence of the surface impedance on the current density). Most previously published nonlinear HTS models can be used, because the algorithms are not restricted to a specific model of HTS nonlinearities. Two different types of algorithms are described: (1) algorithms specific for one-dimensional resonators (transmission lines and TM010 disk resonators) and (2) an algorithm based on the combination of Method of Moments and Harmonic Balance, applicable to 2D planar structures with few restrictions in their shape. Several cross-checks with theory and measurements are presented.Peer Reviewe

HTS nonlinearities in microwave disk resonators

This article describes a procedure for the calculation of the intermodulation behavior of the TM010 mode in high temperature superconducting (HTS) disk resonators from a description of the local HTS nonlinearities. Successful cross-checks are performed by comparing the theoretical results with experimental measurements and simulations based on the multiport harmonic balance algorithm for a specific model of HTS nonlinearity. The application of this procedure to the determination of nonlinear material parameters from disk resonator measurements is illustrated and compared to theoretical predictions.Peer ReviewedPostprint (published version

Nonlinear RF spurious in a cylindrical cavity with superconducting endplates

We have developed a method to calculate the distribution of fundamental and spurious fields in a metallic cylindrical cavity with superconducting endplates in which signals at two different frequencies are injected. The nonlinearity in the superconductor produces the typical intermodulation effects if the frequencies of the injected signals are sufficiently close to each other and near a resonant mode. Our method uses harmonic balance to match the fields in the cavity with the currents on the endplates. The method can be used for a variety of nonlinear models of the superconducting endplate, and could be the base for a nondestructive procedure to extract the nonlinear parameters of an HTS sample from RF measurements. Our analysis is restricted to the TE011 mode, but the method can be applied to any propagating mode in the cylindrical cavity. Closed-form equations for the case of square-law nonlinearities in the superconductor are derived and used to check the validity of the harmonic balance calculation.Peer ReviewedPostprint (published version

Single-molecule analysis of genome uncoating from individual human rhinovirus particles, and modulation by antiviral drugs

Infection of humans by many viruses is typically initiated by the internalization of a single virion in each of a few susceptible cells. Thus, the outcome of the infection process may depend on stochastic single-molecule events. A crucial process for viral infection, and thus a target for developing antiviral drugs, is the uncoating of the viral genome. Here a force spectroscopy procedure using an atomic force microscope is implemented to study uncoating for individual human rhinovirus particles. Application of an increasing mechanical force on a virion led to a high force-induced structural transition that facilitated extrusion of the viral RNA molecule without loss of capsid integrity. Application of force to virions that h ad previously extruded the RNA, or to RNA-free capsids, led to a lower force-induced event associated with capsid disruption. The kinetic parameters are determined for each reaction. The high-force event is a stochastic process governed by a moderate free energy barrier (≈20 kcal mol−1), which results in a heterogeneous population of structurally weakened virions in which different fractions of the RNA molecule are externalized. The effects of antiviral compounds or capsid mutation on the kinetics of this reaction reveal a correlation between the reaction rate and virus infectivityThis work was funded by grants from MICINN/FEDER EU to M.G.M. (RTI2018-096635-B-I00 and PID2021-126973OB-I00) or P.J.P. (FIS2017-89549-R, FIS2017-90701-REDT and PID2021-126608OBI00); a grant from the Human Frontiers Science Program to P.J.P. (HFSPO RGP0012/2018); institutional grants from the Severo Ochoa Program for Centers of Excellence in R&D (CEX2021-00154-S) and Fundación Ramón Areces to the Centro de Biología Molecular “Severo Ochoa” (UAM-CSIC); and an institutional grant from the María de Maeztu Program for Units of Excellence in R&D (MDM-2014-0377) to the Centro de Investigación de Física de la Materia Condensada (UAM). M.G.M. is an associate member of the Institute for Biocomputation and Physics of Complex Systems, Zaragoza, Spai

Classe invertida (flipped classroom). Experiència en el grau d'Infermeria.

Projecte finalitzat desembre 2015En l’aula invertida (flipped classroom) (FC), els estudiants treballen fora de classe, tasques prèviament preparades amb aquest fi pel professorat. L’objectiu del estudi es motivar als estudiants suplint per FC les classes teòriques magistrals. Superar favorablement FC evita l’examen final (30% de l’avaluació). Context d’aplicació: grup C, 89 estudiants (finalitzen n=81). Programa de Ciències Psicosocials Aplicades a la Salut, assignatura anual, formació bàsica, 9 ECTS, primer curs, Grau d’Infermeria, tarda, segon semestre, curs 2014-15. Metodologia: resposta escrita a preguntes amb suport bibliogràfic i avaluació amb instruments específics estandaritzats. A classe: avaluació per parells i contrastos verbals sobre continguts, tutelats per la professora, que presenta una segona avaluació setmanal (campus virtual). Resultats: Contrast estadístic de notes FC amb examen test, igual al realitzat en grup A (intraclasse). Puntuació (sobre 10) superior a FC (mitja: 7,96 + DE: 0,67) que en l’examen (mitja 5,89 + DE: 1,26), <0.001. També es contrasten resultats d’examen de FC i de grup A (mitja: 6,02 + DE 1,18) (interclasse) i no es troben diferencies estadísticament significatives 0.508 . Degut a que el grup C (FC) no s’havia preparat ni estudiat l’examen, la diferencia de dècimes mostra una adquisició de coneixements favorable per la experiència flipped classroom.2014PID-UB/5

Aula invertida: experiencia en el Grado de Enfermería

En el aula invertida, los estudiantes trabajan autónomamente tareas previamente preparadas con este fin por el profesorado. Objetivo: evaluar el aula invertida como innovación docente y contrastar los resultados con grupo con docencia tradicional. Contexto: primer curso del Grado de Enfermería en la asignatura troncal Ciencias Psicosociales Aplicadas a la Salud (grupo C, n=81). Metodología: cualitativa y cuantitativa con la inclusión de instrumentos estandarizados ad hoc. Destaca la evaluación por pares y contrastes verbales sobre contenidos tutelados por el profesorado. Se realizó evaluación del grupo control y el grupo experimental y se contrastaron los resultados de las cualificaciones obtenidas. Resultados. Puntuación sobre 10 con medias y desviación estándar: Intraclase, superior en el aula invertida (7,96 + 0,67) frente a (5,89 + 1,26) en examen (p-valor < 0,001). Interclase, grupo experimental (5,89 + 1,26) y grupo control (6,02 + 1,16), (p-valor 0,508). Sin hallazgo de diferencias estadísticamente significativas. Conclusión: Sin preparación para el examen y gran esfuerzo adicional, destacó la satisfacción por parte del profesorado y de los estudiantes, el aula invertida se mostró claramente favorable para la adquisición de conocimientos en la asignatura de Enfermería probada

Nonequilibrium phase transition in a model for the propagation of innovations among economic agents

We characterize the different morphological phases that occur in a simple one-dimensional model of propagation of innovations among economic agents [X.\ Guardiola, {\it et. al.}, Phys. Rev E {\bf 66}, 026121 (2002)]. We show that the model can be regarded as a nonequilibrium surface growth model. This allows us to demonstrate the presence of a continuous roughening transition between a flat (system size independent fluctuations) and a rough phase (system size dependent fluctuations). Finite-size scaling studies at the transition strongly suggest that the dynamic critical transition does not belong to directed percolation and, in fact, critical exponents do not seem to fit in any of the known universality classes of nonequilibrium phase transitions. Finally, we present an explanation for the occurrence of the roughening transition and argue that avalanche driven dynamics is responsible for the novel critical behavior