Experimental study of MIMO-OFDM transmissions at 94 GHz in indoor environments

Millimeter wave (mm-wave) frequencies have been proposed to achieve high capacity in 5G communications. Although meaningful research on the channel characteristics has been performed in the 28, 38and 60 GHz bands ─in both indoor and short-range scenarios─,only a small number of trials (experiments) have been carried out in other mm-wave bands. The objective of this work is to study the viability and evaluate the performance of the 94 GHz frequency band for MIMO-OFDM transmission in an indoor environment. Starting from a measurement campaign, the performance of MIMO algorithms is studied in terms of throughput for four different antenna configurations.This work was supported in part by the Ministerio de Economía y Competitividad MINECO, Spain under Grant TEC2016-78028-C3-2-P, and in part by the European FEDER funds

Uréter ectópico en el perro : a propósito de dos casos clínicos

A propósito de dos casos clínicos de uréter ectópico en una perra Fax Terrier de siete meses y un Bichón Frissé de 5 meses de edad, el autor hace un breve recuerdo de las manifestaciones clínicas, así como de los medios diagnósticos y quirúrgicos para la resolución del problema del uréter ectópico en el perro.On the finding of two cases of ectopic ureter in a female, seven months old Fox- Terrier,and five months old Bichon Frisse the author makes a short review of tbe clinical signs diagnostics and surgical procedures for the resolution and surgical correction of the ectopic ureter in the dog

Las tasas de mortalidad para la Enfermedad de Parkinson están incrementando en Espana. ˜ Un análisis Edad-Periodo-Cohorte y Joinpoints en las tasas de mortalidad desde 1981 a 2020

Background: Mortality in Parkinson’s disease is increasing worldwide, but Spanish data need further study. Objective: To analyse the mortality trends of Parkinson’s disease in Spain between 1981 and 2020. Methods: This observational retrospective study assessed the Parkinson’s disease mortality data from 1981 to 2020 collected from the National Statistics Institute of Spain. Agestandardised mortality rates were analysed by age and sex groups, detecting significant mortality trends through a joinpoint analysis. Age-period-cohort effect and potential years of life lost analyses were conducted. The European standard population of 2013 was considered for the analyses. Results: A total of 88 034 deaths were assessed. The overall age-standardised mortality rate rose throughout the period from 3.67 to 8.57 per 100 000 inhabitants. Mortality rates in men were higher than in women, 11.63 versus 6.57 deaths per 100 000 inhabitants. The sex ratio showed an increase in premature mortality in men during 2020. The overall joinpoint analysis recorded a rise in mortality, primarily since the 20th century, mainly in male and older groups, that matched with a period effect. The age effect was detected, confirming higher mortality at an older age. The analysis of potential years of life lost detected a growth in this rate, changing from 0.66 in 1981 to 1.06 in 2020. Conclusions: Mortality data for Parkinson’s disease in Spain rose significantly in forty years. Mortality rate was higher in the male and age group above 75 years of age. The sex ratio showed premature mortality in men in 2020, which will need further study.Introducción: La mortalidad de la Enfermedad de Parkinson está incrementando a nivel mundial, pero los datos espanoles ˜ necesitan ser estudiados en profundidad. Objetivo: Analizar las tendencias de mortalidad de la Enfermedad de Parkinson en Espana˜ entre 1981 y 2020. Métodos: Este estudio observacional retrospectivo analizó los datos de mortalidad de la Enfermedad de Parkinson extraídos desde 1981 a 2020 del Instituto Nacional de Estadística de Espana. ˜ Las tasas de mortalidad estandarizada por edad fueron analizadas por grupos de edad y sexo, detectando cambios de tendencia de mortalidad significativos mediate un análisis de joinpoint. Se llevaron a cabo análisis de Edad-Periodo-Cohorte y anos ˜ potenciales de vida perdidos. La población estándar europea fue considerada para el análisis. Resultados: Un total de 88.034 defunciones fueron examinadas. La tasa global de mortalidad estandarizada por edad creció a lo largo del periodo estudiado desde 3,67 a 8,47 por cada 100.000 habitantes. Las tasas de mortalidad fueron mayores en hombre que en mujeres, 11,63 frente a 6,57 fallecimientos por cada 100.000 habitantes. La proporción de sexo mostró un incremento en la mortalidad prematura en hombre durante 2020. El análisis de joinpoint global reportó un aumento de mortalidad, principalmente desde el siglo XX, siendo más notable en hombre y grupos de edad avanzada, que coincidió con un efecto periodo. Se detectó un efecto de edad confirmando una mayor mortalidad a edad más edad avanza. El análisis de anos ˜ potenciales de vida perdidos detectó un crecimiento en esta tasa, cambiando de un 0,66 en 1981 a 1,06 en 2020. Conclusiones: Los datos de mortalidad para la Enfermedad de Parkinson en Espana˜ ha incrementado significativamente durante cuarenta anos. ˜ La tasa de mortalidad fue mayor en hombre y en grupos de edad mayores de 75 anos ˜ de edad. La proporción de sexo mostró una mortalidad prematura en hombres en 2020, que necesitará ser estudiado en mayor profundidad

On the influence of diffuse scattering on multiple-plateau diffraction analysis at mm-wave frequencies

A study of the impact of the diffuse scattering phenomenon when calculating radio wave multiple-plateau diffraction losses at millimeter-wave (mm-wave) frequencies is hereby presented. In this sense, measurements of the total attenuation caused by a series of either rough or polished brick blocks are properly compared with the theoretical multiplediffraction losses of an array of ideally smooth brick blocks predicted by a hybrid uniform theory of diffraction-physical optics (UTD-PO) formulation. The results show the influence of diffuse scattering phenomena when it comes to calculating radio wave multiple-plateau diffraction attenuation and can be applied to the obtaining of more realistic mm-wave propagation models when multiple diffraction over rectangular obstacles with irregular (rough) surfaces has to be considered.This work was supported by the Ministerio de Economía y Competitividad (MINECO), Spain (TEC2016-78028-C3-2-P) and in part by the European Fonds Européen de Développement Économique et Régional Fund

El papel de la reflexión crítica en la construcción de conocimiento práctico docente

It is largely assumed in educational research that adopting a critical awareness (i.e. being able to provide socio-political explanation for events) willbe more effective for scrutinizing teaching action than teachers� habitualthinking (giving accounts of events) or teachers� descriptive reflection (givingpersonal justifications for events) because it provides richer understandings. However, it still remains unclear to what extent critical awareness assists teachers in constructing new situational knowledge, which, in the end,constitutes the ultimate promise of teacher reflection.In this study we attempt to describe the practical knowledge studentteachers show in classroom and to examine whether adopting a critical stancehelps teacher to infer (1) more practical and (2) better quality knowledge (i.e.being precise).One hundred and four preservice teachers, who worked in 73 differentschools, participated in the study. Under supervision of their collaborative teachers, they wrote a report about their teaching. Reports were contentanalyzedfollowing propositional analysis.The findings showed that practical knowledge varies in several degrees of complexity and that critical reflection does not always guarantee the production of more and better local kowledge. This implies that adopting a critical attitude does not necessarily imply a more effective way of redescribing practice than other sorts of thinking.Se asume de modo casi unánime como la reflexión crítica docente (ej. proporcionar explicaciones socio-políticas a los eventos de clase) es más efectiva que el pensamiento habitual (sólo describir los sucesos y hechos) para analizar las situaciones de aula. No obstante aún queda por desvelar si este modo de reflexionar garantiza la construcción de un conocimiento práctico genuino que sea más eficaz para resolver problemas. En este estudio se pretende, por un lado, describir el conocimiento docente que los profesores muestran en su práctica y, por otro; valorar si adoptar una posición crítica permite inferir más conocimientos y de mejor calidad, esto es, más precisos. Ciento cuatro profesores en formación, bajo la supervisión de los profesores tutores de 73 escuelas, participaron en este estudio. Escribieron informes sobre su práctica (ej. dar una clase) y se analizaron proposicionalmente. Los resultados muestran como los conocimientos docentes varían en grado de complejidad y la reflexión crítica no siempre garantiza la producción de mayor y mejor conocimiento práctico. Ello implica que el hecho de sugerir que los profesores adopten una posición crítica como modo eficaz de interpretar su práctica no implica necesariamente una mejora de la misma

Deep learning for the modeling and inverse design of radiative heat transfer

Deep learning is having a tremendous impact in many areas of computer science and engineering. Motivated by this success, deep neural networks are attracting increasing attention in many other disciplines, including the physical sciences. In this work, we show that artificial neural networks can be successfully used in the theoretical modeling and analysis of a variety of radiative-heat-transfer phenomena and devices. By using a set of custom-designed numerical methods able to efficiently generate the required training data sets, we demonstrate this approach in the context of three very different problems, namely (i) near-field radiative heat transfer between multilayer systems that form hyperbolic metamaterials, (ii) passive radiate cooling in photonic crystal slab structures, and (iii) thermal emission of subwavelength objects. Despite their fundamental differences in nature, in all three cases we show that simple neural-network architectures trained with data sets of moderate size can be used as fast and accurate surrogates for doing numerical simulations, as well as engines for solving inverse design and optimization in the context of radiative heat transfer. Overall, our work shows that deep learning and artificial neural networks provide a valuable and versatile toolkit for advancing the field of thermal radiatio

Tunable Thermal Emission of Subwavelength Silica Ribbons

The thermal properties of individual subwavelength objects, which defy Planck’s law, are attracting significant fundamental and applied interest in different research areas. Special attention has been devoted to anisotropic structures made of polar dielectrics featuring thicknesses smaller than both the thermal wavelength and the skin depth. Recently, a novel experimental technique has enabled the measurement of the thermal emissivity of anisotropic SiO2 nanoribbons (with thicknesses on the order of 100 nm), demonstrating that their emission properties can be largely tuned by adjusting their dimensions. However, despite the great interest aroused by these results, their rigorous theoretical analysis has remained elusive due to the computational challenges arising from the vast difference in the length scales involved in the problem. In this work, we present a systematic theoretical analysis of the thermal emission properties of these dielectric nanoribbons based on simulations within the framework of fluctuational electrodynamics carried out with the boundary element method implemented in the SCUFF-EM code. In agreement with the experiments, we show that the emissivity of these subwavelength structures can be largely tuned and enhanced over the thin-film limit. We elucidate that the peculiar emissivity of these nanoribbons is due to the very anisotropic thermal emission that originates from the phonon polaritons of this material and the properties of the waveguide modes sustained by these dielectric structures. Our work illustrates the rich thermal properties of subwavelength objects, as well as the need for rigorous theoretical methods that are able to unveil the complex thermal emission phenomena emerging in this class of systemsJ.J.G.E. was supported by the Spanish Ministry of Science and Innovation through an FPU grant (FPU19/05281). J.B.A. acknowledges financial support from the Ministerio de Ciencia, Innovacioń y Universidades (RTI2018-098452-B-I00). J.C.C. acknowledges funding from the Spanish Ministry of Science and Innovation (PID2020-114880GB-I00

Morphology and interactivity of the contents in the applications of Latin American television

[Resumen] Introducción. Conocer la operativa del sistema audiovisual en la comunicación móvil, es el objetivo principal de esta investigación. Para ello se analizan los contenidos audiovisuales y la eficacia de las aplicaciones para smartphone iOS y Android de las principales cadenas de televisión públicas y privadas de los cincos primeros países latinoamericanos según datos del PIB Nominal: Argentina, Brasil, Chile, Colombia y México. Metodología. Se desarrolla un estudio cuantitativo, basado en técnicas de análisis de contenido. Resultados y conclusiones. En general, las apps analizadas se pueden descargar desde España, pero el acceso a sus contenidos audiovisuales es muy limitado, ya que es habitual que no se puedan visualizar desde fuera del país de origen. La mayoría de las televisiones estudiadas vuelcan sus programas en la aplicación tal y como fueron emitidos en el canal tradicional. Su principal finalidad es ofrecer contenidos y en pocos casos interactividad.[Abstract] Introduction. The main objective of this research is to learn about the operation of the audiovisual system in mobile communication. In order to do so, there is an analysis of the audiovisual contents and effectiveness of the smartphone apps iOS and Android's of the main public and private television networks of the five first Latin American countries based on the Nominal GDP: Argentina, Brazil, Chile, Colombia and Mexico. Methods. To develop a quantitative study, based on content analysis techniques. Results and conclusions. In general, analysed apps can be downloaded from Spain but access to their audiovisual content is very limited, since in most cases it cannot be accessed from outside the country of origin. Most of television networks studied, dump their programmes into the application as they were broadcasted in the traditional channel. Its main purpose is to offer contents and, in a few cases, interactivity