- DO WIVES EARNINGS CONTRIBUTE TO REDUCE INCOME INEQUALITY?: EVIDENCE FROM SPAIN

In this paper we analyze the effect of female labor force participation on income inequality. We present evidence from Spain by using data from the Family Expenditure Survey for 1980 and 1990. The case of Spain is particulary interesting because inequality decreased over the eighties, while the labor force participation rate of married women increased substantially over the same period. Our results show that although female labor force participation has contributed to decrease income inequality in Spain, it is far from being one of the main factors behind the observed decrease in inequality over the eighties.Income Ínequality; Female Earnings; Female Participation.

Does student proactivity guarantee positive academic results?

This paper analyzes the impact of students’ proactivity on academic performance based on a sample from students enrolled in an introductory course of Political Economy at the University of Seville (Spain) in three consecutive courses (2014–2015, 2015–2016 and 2016–2017). Proactivity is measured by several indicators, such as class attendance, case-study oral presentation and its delivery in a foreign language, all of them being non-mandatory activities for students who have participated in the experiment. Specifically, this study aims to assess the impact of a student’s proactivity on two academic outcomes: (i) to pass or fail the exam; and (ii) the score obtained. Impact assessment has been performed using a probit and ordered multinomial logit models. The results show that a student’s proactivity measured by class attendance and case-study presentation significantly increases the probability of passing the exam, while the impact of using a foreign language seems to be non-significant. In relation to the score obtained, the proactivity measured through the case presentation raises the probability of obtaining a higher mark more than regular class attendance.Junta de Andalucía proyecto SEJ-132Universidad Autónoma de ChileUniversidad de Sevilla. Departamento de Análisis Económico y Política Económic

Efficiency analysis of wide band-gap semiconductors for two-level and three-level power converters

© 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Power devices based on wide band-gap materials are emerging as alternatives to silicon-based devices. These new devices allow designing and building converters with fewer power losses, and are thus more highly efficient than traditional power converters. Among the wide band-gap materials in use, silicon carbide (SiC) and gallium nitride (GaN) devices are the most promising because of their excellent properties and commercial availability. This paper compares the losses produced in two-level and three-level power converters that use the aforementioned technologies. In addition, we assess the impact on the converter performance caused by the modulation technique. Simulation results under various operating points are reported and compared.Peer ReviewedPostprint (author's final draft

Influencia meteorológica en la incidencia de la epistaxis

Resumen Introducción: La epistaxis espontánea es una de las urgencias otorrinolaringológicas más frecuentes. Aun así, su incidencia y epidemiología real es difícil de establecer ya que, al ser un cuadro benigno y autolimitado la mayoría de veces, los pacientes no precisan atención médica y no queda registro en los hospitales de estos episodios. Además de los factores de riesgo clásicos, diversos autores hablan de la influencia que puede tener la meteorología en su incidencia, sobre todo cambios en la temperatura media diaria, en el porcentaje de humedad diario y en la presión atmosférica media diaria. Método: Se realizó un estudio descriptivo usando información de la base de datos del hospital sobre pacientes admitidos con epistaxis espontánea entre el 1 de enero y el 31 de diciembre de 2016, ambos inclusive. La información meteorológica se obtuvo para el mismo periodo de tiempo de la Agencia Estatal de Meteorología. Se estudió la correlación entre los casos registrados como epistaxis y las variables meteorológicas usando el test de U de Mann-Whitney. Resultados: durante el periodo de estudio hubo 469 casos de epistaxis, correspondientes a 333 pacientes, 183 hombres (media de edad 58,56 años) y 150 mujeres (media de edad 60,06 años). El factor de riesgo más frecuente fue la existencia de HTA (56,45 %), y la toma de tratamiento anticoagulante o antiagregante (43,84 %). No se obtuvieron diferencias estadísticamente significativas en la incidencia de epistaxis debido a variables atmosféricas. Conclusiones: aunque no se hayan encontrado diferencias significativas, los resultados sugieren una alta influencia de los cambios bruscos de los parámetros atmosféricos en la incidencia de la epistaxis, al aumentar esta en los meses más fríos del año o en los cambios de estación. Palabras clave: “Epistaxis espontánea”, “incidencia epistaxis”, “presión atmosférica” “factores meteorológicos “

Effect of the heat dissipation system on hard-switching GaN-based power converters for energy conversion

The design of a cooling system is critical in power converters based on wide-bandgap (WBG) semiconductors. The use of gallium nitride enhancement-mode high-electron-mobility transistors (GaN e-HEMTs) is particularly challenging due to their small size and high power capability. In this paper, we model, study and compare the different heat dissipation systems proposed for high power density GaN-based power converters. Two dissipation systems are analysed in detail: bottom-side dissipation using thermal vias and top-side dissipation using different thermal interface materials. The effectiveness of both dissipation techniques is analysed using MATLAB/Simulink and PLECS. Furthermore, the impact of the dissipation system on the parasitic elements of the converter is studied using advanced design systems (ADS). The experimental results of the GaN-based converters show the effectiveness of the analysed heat dissipation systems and how top-side cooled converters have the lowest parasitic inductance among the studied power converters.This work was supported by the Industrial Doctorates Plan of the Secretaria d’Universitats i Recerca del Departament d’Empresa i Coneixement de la Generalitat de Catalunya, the Centro para el Desarrollo Tecnológico Industrial (IDI-20200864), and the Ministerio de Ciencia, Innovación y Universidades of Spain within the project PID2019-111420RB-I00Peer ReviewedPostprint (published version

Efficiency comparison of power converters based on SiC and GaN semiconductors at high switching frequencies

© 2021 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Hard-switching voltage source converters (VSC) based on wide-bandgap (WBG) devices surpass their silicon equivalents in every aspect. Nevertheless, at high switching frequencies, the efficiency significantly differs depending on the WBG semiconductor used. This article presents an extensive comparison between gallium nitride (GaN), and silicon carbide (SiC) devices in terms of efficiency. The impact of the switching frequency is evaluated for each semiconductor using two modulation techniques: the classical space vector pulse width modulation (SVPWM) technique, and the innovative hexagonal sigma-delta modulation (H-S¿). The performance and losses of both WBG technologies are analysed here using Matlab/Simulink and PLECS. Experimental results performed on two VSC converters, one based on SiC devices and the other made using GaN transistors, show the influence of the semiconductor technology and the modulation strategy on the efficiency at high switching frequenciesPeer ReviewedPostprint (published version

Fast-processing sigma-delta strategies for three-phase wide-bandgap power converters with common-mode voltage reduction

© 2022 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.The electromagnetic compatibility of wide-bandgap (WBG) power converters can be greatly improved using spread-spectrum modulation techniques. This article proposes a family of reduced common-voltage sigma–delta modulations (RCMV- S¿ ) for voltage source converters (VSC) that use gallium nitride (GaN) semiconductors. Specifically, this article proposes three new techniques: two reduced-state sigma–delta modulations (RS- S¿1 &2), and an active sigma–delta strategy (A- S¿ ). The proposed modulation techniques reduce or eliminate the common-mode voltage (CMV) dv/dt transitions and suppress the noise spikes in the conducted electromagnetic interference spectrum. Furthermore, this article proposes the use of fast-processing quantizers for RCMV- S¿ techniques as well as for hexagonal sigma–delta (H- S¿ ). These quantizers use a novel calculation methodology that simplifies the implementation of the proposed modulations and considerably reduces their computational cost. The performance and the total harmonic distortion (THD) of RCMV- S¿ techniques are analyzed here using MATLAB/Simulink and PLECS. Experimental results performed on a VSC converter that uses GaN e-HEMTs show how RCMV- S¿ techniques considerably improve electromagnetic compatibility and exhibit similar efficiencies and THD to those of H- S¿ .This work was supported by the Industrial Doctorates Plan of the Secretaria d’Universitats i Recerca del Departament d’Empresa i Coneixement de la Generalitat de Catalunya, the Centro para el Desarrollo Tecnológico Industrial (IDI-20200864), and in part by the Ministerio de Ciencia, Innovación y Universidades of Spain under Project PID2019-111420RB-I00.Peer ReviewedPostprint (published version

Satisfacción de los pacientes intervenidos de Turbinoplastia

Introducción y objetivos: La obstrucción nasal es uno de los motivos más frecuentes de consulta tanto en Atención Primaria como en Otorrinolaringología, afectando de manera importante a la calidad de vida. Una de las causas más frecuentes es la hipertrofia de cornetes y ésta puede ser tratada tanto médica como quirúrgicamente con diversas técnicas entre las que destaca la turbinoplastia por Radiofrecuencia, actualmente de moda. Por esta razón, se plantea el presente estudio con el fin de estudiar la satisfacción de los pacientes intervenidos con esta técnica y cómo influyen diversas variables en sus resultados.Método: Se seleccionó una muestra de 20 pacientes procedentes de las consultas externas del servicio de Otorrinolaringología del HCU de Zaragoza que fueron intervenidos durante los meses de enero, febrero, marzo, abril y mayo de 2022. Se les pasó un cuestionario de calidad de vida (CQ-7) antes y después de la intervención.Resultados: No se observa relación entre las variables rinitis, sexo, edad y los resultados obtenidos en los cuestionarios tras la intervención. En cuanto a las variables ser asmático y ser fumador sí que existe una relativa asociación.Conclusiones: La turbinoplastia por Radiofrecuencia es un procedimiento quirúrgico bien tolerado, con excelentes resultados a corto plazo (un mes tras la operación). Esto se revela en la variación de puntuación entre los resultados pre y post quirúrgicos.<br /

Plant water status indicators for detecting water stress in pomegranate trees

Measurements obtained by the continuous monitoring of trunk diameter fluctuations were compared with discrete measurements of midday stem water potential (stem) and midday leaf conductance (gl) in adult pomegranate trees (Punica granatum (L.) cv. Mollar de Elche). Control plants (T0) were irrigated daily above their crop water requirements in order to attain non‐limiting soil water conditions, while T1 plants were subjected to water stress by depriving them of irrigation water for 34 days, after which time irrigation was restored and plant recovery was studied for 7 days. T1 plants showed a substantial degree of water stress, which developed slowly. Maximum daily trunk shrinkage (MDS) was identified to be the most suitable plant‐based indicator for irrigation scheduling in adult pomegranate trees, because its signal:noise ((T1/T0):coefficient of variation) ratio was higher than that for stem ((T1/T0):coefficient of variation) and gl ((T0/T1):coefficient of variation). MDS increased in response to water stress, but when the stem fell below −1.67 MPa, the MDS values decreased.This research was supported by CICYT/FEDER (AGL2010‐19201‐C04‐01AGR) and AECID (A1/035430/11) grants to the authors. AG, JCG and ZNC were funded by a FPU, a FPI and a AECID grant, respectively