Brewster quasi bound states in the continuum in all-dielectric metasurfaces from single magnetic-dipole resonance meta-atoms.

Bound states in the continuum (BICs) are ubiquitous in many areas of physics, attracting special interest for their ability to confine waves with infinite lifetimes. Metasurfaces provide a suitable platform to realize them in photonics; such BICs are remarkably robust, being however complex to tune in frequency-wavevector space. Here we propose a scheme to engineer BICs and quasi-BICs with single magnetic-dipole resonance meta-atoms. Upon changing the orientation of the magnetic-dipole resonances, we show that the resulting quasi-BICs, emerging from the symmetry-protected BIC at normal incidence, become transparent for plane-wave illumination exactly at the magnetic-dipole angle, due to a Brewster-like effect. While yielding infinite Q-factors at normal incidence (canonical BIC), these are termed Brewster quasi-BICs since a transmission channel is always allowed that slightly widens resonances at oblique incidences. This is demonstrated experimentally through reflectance measurements in the microwave regime with high-refractive-index mm-disk metasurfaces. Such Brewster-inspired configuration is a plausible scenario to achieve quasi-BICs throughout the electromagnetic spectrum inaccessible through plane-wave illumination at given angles, which could be extrapolated to other kind of waves.

Extraordinary optical reflection from sub-wavelength cylinder arrays.

A multiple scattering analysis of the reflectance of a periodic array of sub-wavelength cylinders is presented. The optical properties and their dependence on wavelength, geometrical parameters and cylinder dielectric constant are analytically derived for both s- and p-polarized waves. In absence of Mie resonances and surface (plasmon) modes, and for positive cylinder polarizabilities, the reflectance presents sharp peaks close to the onset of new diffraction modes (Rayleigh frequencies). At the lowest resonance frequency, and in the absence of absorption, the wave is perfectly reflected even for vanishingly small cylinder radii.

Características y factores asociados al maltrato percibido en internos de medicina en Perú / Characteristics and associated factors with mistreatment perception in medical interns in Peru

RESUMEN Objetivo: Determinar las características y factores asociados a la percepción de maltrato en internos de medicina del Perú. Materiales y métodos : Estudio multicéntrico, transversal y analítico. Se encuestaron a internos de medicina de dieciocho hospitales del Perú. Se aplicó una encuesta entre marzo y abril del 2016 que incluían características sociodemográficas y una escala que media la percepción de maltrato psicológico, físico y sexual. Se realizaron modelos lineales generalizados y se estimaron razones de prevalencia crudas y ajustadas (RPa) con intervalos de confianza al 95%. Resultados : Participaron 418 internos de medicina. El maltrato psicológico, físico y sexual percibido fue de 91,9%; 55,5% y 34%, respectivamente. Los factores asociados con el maltrato psicológico fueron proceder de una universidad privada (RPa:1,07; IC95%:1,01- 1,13), respecto al maltrato físico fueron la edad (RPa: 1,08; IC95%: 1,05-1,12), realizar internado en un hospital de la selva (RPa: 1,27; IC95%: 1,03-1,56) y en un hospital del Seguro Social (RPa:0,66; IC95%:0,44-0,94) y para el maltrato sexual el ser mujer (RPa:1,52; IC95%:1,15-2,01). Conclusiones : Existe una alta percepción de maltrato reportado por los internos de medicina siendo el psicológico el más frecuente. Existen diferencias en la percepción de maltrato psicológico y físico según el tipo de financiamiento de la universidad de procedencia y del hospital donde se realiza el internado. Una alta frecuencia de maltrato sexual fue reportada por mujeres luego de los tres primeros meses del internado hospitalario.

ABSTRACT Objective: To determine the characteristics and factors associated with the perception of abuse in medicine interns of Peru. Material and Methods : This is a cross-sectional multicenter and analytical study. Medicine interns from eighteen Peruvian hospitals were interviewed. A survey was administered between March and April 2016, which included socio-demographic characteristics and a scale measuring psychological and physical abuse, as well as sexual harassment perception. Generalized linear models were used and crude and adjusted prevalence rates (aPR) were estimated, with 95% confidence intervals (CI). Results: 418 medical interns participated in the study. Psychological and physical abuses were perceived by 91,9% and 55,5% of the studied population. Sexual harassment was perceived by 34% of all interviewed interns. Associated factors with psychological abuse were studied in a private university (aPR: 1.07; 95% CI: 1.01-1.13). Factors associated with physical abuse were age (aPR: 1.08; 95% IC: 1.05-1.12), performing internship in an Amazonian area hospital (aPR: 1,27; 95% CI: 1,03-1,56), and in a Social Security Hospital (aPR: 0,66; 95% CI: 0,44-0,94); and for sexual harassment, being female was the main associated factor (aPR: 1,52; 95% CI: 1,15-2,01). Conclusions: There is a high perception of abuse experienced by medicine interns, being psychological abuse the most frequent condition. There are some differences in the perception of psychological and physical abuse, according to the medical school the interns come from, as well as with respect to the healthcare facility where internship is performed. A high frequency of sexual harassment was reported by female interns after three months of having started their training period.

Bioseguridad respiratoria practicada en ambientes laborales de catorce ciudades peruanas: Estudio piloto / Respiratory biosecurity practiced in work environments of fourteen peruvian cities: pilot study

Objetivo: caracterizar la bioseguridad respiratoria que practican los trabajadores en catorce ciudades del Perú. Metodología: trabajo transversal descriptivo de tipo multicéntrico, a través de una encuesta auto-aplicada, donde se consultó temas relacionados con la bioseguridad respiratoria y de las prácticas de higiene que tenían. Estos se describieron con frecuencias y porcentajes. Resultados: de los 4287 encuestados, el 68% (2913) fueron hombres, la mediana de edades fue de 31 años (rango intercuartílico: 24-40 años). El 91% y el 53% sabían para que se usan las mascarillas respiratorias y la forma de trasmisión de las enfermedades respiratorias, respectivamente. El 46% se auto-medica cuando está resfriado; se han vacunado contra la gripe estacional entre 31-41% para los trabajadores, familiares o compañeros de trabajos, estos porcentajes suben cuando se les preguntó si se vacunarían el año en curso y la mayoría de los que no se vacunarían es porque no saben dónde (rango: 35-40%); el brazo y la mano son los más usados para cubrirse cuando estornudan. Conclusión: estas características muestran a una población que puede ser susceptible a contraer y trasmitir enfermedades respiratorias, por lo que se deben tomar medidas de educación e intervenciones para la mejora del conocimiento/actitudes y la generación de prácticas adecuadas

Objective: to describe biosecurity of respiratory diseases practiced by workers in fourteen cities of Peru. Methodology: a descriptive multicenter cross-sectional study was carried out in February through a self-administered questionnaire, where some concepts related to biosecurity of respiratory diseases and hygiene practices were asked. These were described in frequencies and percentages. Results: Of the 4287 respondents, 68% (2913) were men; the average age was 31 years piloto(interquartile range: 24-40 years). 91% and 53% knew what respiratory masks are used for and how respiratory diseases are transmitted, respectively. 46% self-medicate when they have the cold; 31-41% of workers, relatives or co-workers have been vaccinated against seasonal flu, these percentages go up when they were asked if they would be vaccinated in current year and most would not be vaccinated because they do not know where (Range: 35-40%); the arm and the hand are the most used to cover when sneezing. Conclusion: These characteristics show a population that may be susceptible to get and transmit respiratory diseases, so educational measures and interventions should be taken to improve knowledge/attitudes and to create good practices

Fast and non-invasive conductivity determination by the dielectric response of reduced graphene oxide: an electrostatic force microscopy study.

The high dispersion found in the literature for the conductivity of Reduced Graphene Oxide (RGO) layers makes it highly desirable to develop fast and non-invasive methods for their characterization. Here we show that Electrostatic Force Microscopy (EFM) is an in situ, fast, and contactless technique to evaluate the conductivity of chemically derived graphene layers. The dielectric response of RGO flakes is observed to depend on their conductivity in the range of 0-3 S m(-1). Interestingly, we also find that for electrostatic purposes, a graphene layer is equivalent to an extremely thin dielectric layer with an effective permittivity (ε(eff)) that depends on the conductivity of the layers and spans from 5 for the insulating layers, to 2000 for the more conductive ones. We discuss how these high values of ε(eff) are a consequence of the incomplete screening of electric fields through graphene layers.

The BrainMap strategy for standardization, sharing, and meta-analysis of neuroimaging data.

BACKGROUND: Neuroimaging researchers have developed rigorous community data and metadata standards that encourage meta-analysis as a method for establishing robust and meaningful convergence of knowledge of human brain structure and function. Capitalizing on these standards, the BrainMap project offers databases, software applications, and other associated tools for supporting and promoting quantitative coordinate-based meta-analysis of the structural and functional neuroimaging literature. FINDINGS: In this report, we describe recent technical updates to the project and provide an educational description for performing meta-analyses in the BrainMap environment. CONCLUSIONS: The BrainMap project will continue to evolve in response to the meta-analytic needs of biomedical researchers in the structural and functional neuroimaging communities. Future work on the BrainMap project regarding software and hardware advances are also discussed.