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Based on the transfer matrix method, we studied theoretically the transmittance of a 1D photonic crystal (PC), consisting of alternating layers of a dielectric material (BaTiO3) and a superconductor (YBa2Cu3O7−x). The dielectric properties of this system are described by the two fluid model. We have investigated the transmittance intensity and its bandwidth dependence on the superconductor thickness, incident angle, and temperature in the PC. It was found that the electromagnetic wave propagation can be controlled to be forbidden or allowed in certain wavelengths in the visible and ultraviolet range, and the photonic band gap (PBG) width can also be tuned varying these parameters. We showed that by increasing the thickness of the superconductor layer it is possible to control the number of PBGs in the structure. Also, we found that the frequency ranges of PBGs are sensitive to the incident angle and the polarization of the electromagnetic waves; the bandwidth of PBGs can be notably enlarged by increasing the angle in the TE polarization, but narrowed in the TM one. Additionally, we found that transmission is not markedly affected by temperature variation, but small shifts in the PBGs are presented. We hope these results can be of technical use for developing potential applications in optoelectronic devices. [ABSTRACT FROM AUTHOR]

Copyright of Revista Técnica Energía is the property of Centro Nacional de Control de Energia CENACE and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this article, we aim to estimate what the cost of Covid-19 has been in terms of unemployment for Spain. We use a simple autoregressive model to simulate what the unemployment rate would have been without the pandemic and we compare this with the actual values. We also forecast the unemployment rate for 2021 and 2022 to analyse the persistence of the pandemic shock to unemployment.

Astrophysics was born in the nineteenth century as a “New Astronomy” (in the words of Samuel Langley, 1884), a knowledge built primarily by amateurs who explored deep space by studying the Sun, stars and nebulae. They were credible enough to interest physicists who did research on the properties of radiation and hence came to constitute a solid and recognised discipline. The aim of this research is to study the contribution of artisanal knowledge in the construction of this new discipline at two distinct moments. The first, when artisans worked to find a standard to normalise the manufacture of the glass with which the lenses of refracting telescopes were manufactured. The most recognised of these artisans was Fraunhöfer. The second moment occurred when the experience of artisan knowledge enabled the manufacture of instruments that improved the traditional classification of the magnitude of the stars. The search for standards led to an alliance between artisans and scientists during the same period in which spectroscopy was carried out. In this case, a unit of luminous intensity was sought that could serve as a standard to classify the stars by their luminosity. Industries, university laboratories and astronomers interested in solar astronomy (such as Karl F. Zöllner), collaborated with the artisan manufacturers of measuring devices, and gave rise to a paradigmatic case of science and industry transfer.

Copyright of Revista Médica MD is the property of Comite Editorial de la Revista Medica MD and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Although it is not a new phenomenon, in recent years inequality has moved to the top of the political agenda given the concern that will result in political instability and social resentment. Persistence in inequality can further undermine economic growth and development by hindering educational opportunities, human capital formation, and intergenerational mobility. The persistent nature of inequality stands as one of the most serious challenges for the global economy. This paper analyses inequality persistence for a sample of 60 countries from 1984 to 2015. The authors conclude that inequality is persistent and government redistribution polices through taxes and transfers did not significantly reduce inequality persistence.

Copyright of Revista Ingeniería e Investigación is the property of Universidad Nacional de Colombia, Facultad de Ingenieraia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Few studies have defined how the risk of hospital-acquired acute renal failure varies with the level of estimated glomerular filtration rate (GFR). It is also not clear whether common factors such as diabetes mellitus, hypertension and proteinuria increase the risk of nosocomial acute renal failure independent of GFR. To determine this we compared 1,746 hospitalized adult members of Kaiser Permanente Northern California who developed dialysis-requiring acute renal failure with 600,820 hospitalized members who did not. Patient GFR was estimated from the most recent outpatient serum creatinine measurement prior to admission. The adjusted odds ratios were significantly and progressively elevated from 1.95 to 40.07 for stage 3 through stage 5 patients (not yet on maintenance dialysis) compared to patients with estimated GFR in the stage 1 and 2 range. Similar associations were seen after controlling for inpatient risk factors. Pre-admission baseline diabetes mellitus, diagnosed hypertension and known proteinuria were also independent risk factors for acute kidney failure. Our study shows that the propensity to develop in-hospital acute kidney failure is another complication of chronic kidney disease whose risk markedly increases even in the upper half of stage 3 estimated GFR. Several common risk factors for chronic kidney disease also increase the peril of nosocomial acute kidney failure.Kidney International (2008) 74, 101–107; doi:10.1038/ki.2008.107; published online 2 April 2008 [ABSTRACT FROM AUTHOR]

Superconductivity could become an enabling technology for all-electric aircraft propulsion. Historically, aircraft design is based on extrapolation of past experience, meaning that a new aircraft is an improvement of existing designs. Since an all-electric aircraft would be based on new technologies, its design requires the creation of new tools. Physics-based models have to be developed for all the components of the aero-vehicle. This paper presents a physics-based model for superconducting motors to be used in a synthesis and optimization program commonly used by aircraft designers. The model is able to generate a motor design from propulsion requirements providing weight, volume, efficiency, armature temperature, etc. The temperature rise in the armature is an important limiting factor in superconducting motors; this is calculated through a thermal model of the armature based on equivalent lumped parameter circuit. All the electrical and thermal parameters are used for optimization of the motor. The paper presents a design example based on a typical small aircraft. [ABSTRACT FROM AUTHOR]