909 research outputs found
Broadband mixing of PT-symmetric and PT-broken phases in photonic heterostructures with a one-dimensional loss/gain bilayer
Combining loss and gain components in one photonic heterostructure opens a new route to efficient manipulation by radiation, transmission, absorption, and scattering of electromagnetic waves. Therefore, loss/gain structures enabling PT-symmetric and PT-broken phases for eigenvalues have extensively been studied in the last decade. In particular, translation from one phase to another, which occurs at the critical point in the two-channel structures with one-dimensionalloss/gain components, is often associated with one-way transmission. In this report, broadband mixing of the PT-symmetric and PT-broken phases for eigenvalues is theoretically demonstrated in heterostructures with four channels obtained by combining a one-dimensional loss/gain bilayer and one or two thin polarization-converting components (PCCs). The broadband phase mixing in the four-channel case is expected to yield advanced transmission and absorption regimes. Various configurations are analyzed, which are distinguished in symmetry properties and polarization conversion regime of PCCs. The conditions necessary for phase mixing are discussed. The simplest two-component configurations with broadband mixing are found, as well as the more complex three-component configurations wherein symmetric and broken sets are not yet mixed and appear in the neighbouring frequency ranges. Peculiarities of eigenvalue behaviour are considered for different permittivity ranges of loss/gain medium, i.e., from epsilon-near-zero to high-epsilon regime
Multi-wavelength temporal and spectral analysis of Blazar S5 1803+78
Blazars are a class of AGN, one of their jets is pointed towards the earth.
Here, we report about the multi-wavelength study for blazar S5 1803+78 between
MJD 58727 to MJD 59419. We analysed -ray data collected by Fermi-LAT,
X-ray data collected by Swift-XRT \& NuSTAR, optical photons detected by
Swift-UVOT \& TUBITAK observatory in Turkey. Three flaring states are
identified by analysing the -ray light curve. A day scale variability
is observed throughout the flares with the similar rise and decay times
suggesting a compact emission region located close to the central engine.
Cross-correlation studies are carried out between -ray, radio, and
X-ray bands, and no significant correlation is detected. The -ray and
optical emission are significantly correlated with zero time lag suggesting a
co-spatial origin of them. A significant positive correlation between the R-I
index and the V magnitude is observed. The broadband spectral energy
distributions (SEDs) modeling was performed for all the flaring episodes as
well as for one quiescent state for comparison. SEDs are best fitted with the
synchrotron-self Compton (SSC) model under a one-zone leptonic scenario. The
SED modeling shows that to explain the high flaring state strong Doppler
boosting is required.Comment: 13 pages, 14 figures, 4 tables, Accepted in MNRA
Protocol study: Sexual and reproductive health knowledge, information-seeking behaviour and attitudes among Saudi women: A questionnaire survey of university students
Copyright © 2014 Farih et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.Background - Sexual and reproductive health (SRH), a basic right for women worldwide, is infrequently researched in countries in the Middle East and North Africa (MENA). No empirical studies of SRH among Saudi women exist. This protocol describes a study to explore the SRH knowledge, information-seeking behaviour and attitudes of Saudi female university students.
Methods/Design - This study will administer a questionnaire survey to female students at 13 universities in Riyadh, Saudi Arabia. The questionnaire was developed following a literature search to identify relevant content, with psychometrically tested tools used when available. The content layout and the wording and order of the questions were designed to minimize the risk of bias. The questionnaire has been translated into Arabic and piloted in preparation for administration to the study sample. Ethical approval for the study has been granted (reference no. QMREC2012/54). After questionnaire administration, the data will be collated, analysed and reported anonymously. The findings will be published in compliance with reporting guidelines for survey research.
Discussion - This study will be the first to provide fundamental information concerning Saudi females university students SRH knowledge and information needs.King Abdullah Scholarship Program, Saudi Arabi
InterPack2003-35030 DEFORMATION AND DAMAGE IN SOLDER DURING FAST CYCLIC LOADING
ABSTRACT Experimental and numerical studies on fast cyclic loading of eutectic tin-lead solder and relevant micromechanical issues are presented. High-frequency twin-lap shear tests on solder joints show cracking inside the solder but often connecting the intruded tips of the intermetallic. Finite element modeling was carried out to study the effect of intermetallic morphology. Without the influence of local phase coarsening, the intrusion of intermetallic into the solder alloy is seen to trigger strain localization which promotes failure. The effect of local phase coarsening was also studied numerically, taking into account the individual phase arrangement. A coarser phase structure always shows a faster accumulation of local plastic strain, leading to early failure. Such results, in agreement with typical thermomechanical fatigue features, cannot be obtained from the traditional argument of strength vs. microstructural size. Modeling of the entire lap-shear specimen was also conducted for the purpose of quantifying the deformation behavior. The exact geometry of solder is found to play a dominant role in affecting the shear response
Statin pretreatment diminishes the levels of myocardial ischemia markers not only in CABG
A response to Ege E, Dereli Y, Kurban S, Sarigul A: Atorvastatin pretreatment diminishes the levels of myocardial ischemia markers early after CABG operation: an observational study. J Cardiothorac Surg 2010, 5:60
Analysis of the intra-night variability of BL Lacertae during its August 2020 flare
We present an analysis of the photometry of the blazar BL Lacertae on
diverse timescales from mid-July to mid-September 2020. We have used 11
different optical telescopes around the world and have collected data over 84
observational nights. The observations cover the onset of a new activity phase
of BL Lacertae started in August 2020 (termed as the August 2020 flare by us),
and the analysis is focused on the intra-night variability. On short-term
timescales, (i) flux varied with ~2.2\,mag in band, (ii) the spectral index
was found to be weakly dependent on the flux (i.e., the variations could be
considered mildly chromatic) and (iii) no periodicity was detected. On
intra-night timescales, BL Lacertae was found to show bluer-when-brighter
chromatism predominantly. We also found two cases of significant inter-band
time lags of the order of a few minutes. The duty cycle of the blazar during
the August 2020 flare was estimated to be quite high (~90\% or higher). We
decomposed the intra-night light curves into individual flares and determined
their characteristics. On the basis of our analysis and assuming the turbulent
jet model, we determined some characteristics of the emitting regions: Doppler
factor, magnetic field strength, electron Lorentz factor, and radius. The radii
determined were discussed in the framework of the Kolmogorov theory of
turbulence. We also estimated the weighted mean structure function slope on
intra-night timescales, related it to the slope of the power spectral density,
and discussed it with regard to the origin of intra-night variability.Comment: 46 pages, 19 figures, 8 tables, accepted for publication in The
Astrophysical Journal Supplement Series (manuscript version after proof
correction
Prenatal Vitamin D Supplementation and Child Respiratory Health: A Randomised Controlled Trial
PMCID: PMC3691177This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
The New Mexico State University Satellite (NMSUSat) Mission
The New Mexico State University Satellite (NMSUSat) is part of the University Nanosat 3 program managed by the Air Force Research Laboratory and it is being developed at New Mexico State University. The planned Science Mission for the satellite is to perform Near Ultra Violet emission intensity measurements of the earth\u27s upper atmosphere over the night side of the earth. The Engineering Mission is to demonstrate techniques for distributed data relaying over the Internet and to conduct an energy storage experiment to assess the operational characteristics of double layer capacitors. The Educational Mission of the program to assist in the further development of the aerospace engineering concentration area in the College of Engineering and to develop multi-disciplinary capstone and design classes for students in engineering departments, computer science, and the engineering physics program. This paper will discuss the preliminary design for the satellite components and how the mission segments will be worked among the participating departments at New Mexico State University
Reply to Comments on Effect of heating rate on kinetic parameters of beta-irradiated Li2B4O7:Cu,Ag,P in TSL measurements
We appreciate the opportunity to respond to comments regarding the paper published by Ege et al (2007 Effect of heating rate on kinetic parameters of beta-irradiated Li2B4O7: Cu, Ag, P in TSL measurements Meas. Sci. Technol. 18 889). We would like to thank the authors for taking the time to tell us about their opinion, but unfortunately we do not agree with them completely. In the article presented by Kumar and Chourasiya some comment is advanced to the analysis of the glow curves measured with different heating rates, presented in our recent study. According to our study, the area under the glow curve decreases with increasing heating rate in TL-temperature plots due to the quenching effects. Contrary to this, Kumar and Chourasiya suggest that this decrease is due to the normalization process. Here we hope to clarify any confusion regarding our published study
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