American University of Sharjah

• Sharjah, United Arab Emirates
Recent publications
This article studies skew generalized quasi-cyclic codes (SGQC-codes) over finite fields for any length n. We derive generator polynomials and cardinality of SGQC codes. Moreover, we show that the dual of any length SGQC-code is also an SGQC-code. Our search results lead to the construction of fifteen new 2-generator SGQC codes over the finite field F4 with minimum distances exceeding the minimum distances of the previously best known F4-linear codes with comparable parameters.
The fluctuated output power of the large-scale wind farms (WF) and their fault transient characteristics have an adverse effect on the current differential protection systems of the transmission lines. With increased transmission line length and in the case of weak output power from the WF, the differential current between both line ends increases in normal conditions since the capacitive current is comparable to the load current. This paper proposes a new differential protection algorithm for transmission lines connected to large-scale wind farms. The proposed current differential protection algorithm is developed based on the signs of the phase current samples at both line ends, instead of utilizing directly the current magnitudes. The similarity between the signs of the phase current samples at both line ends is evaluated utilizing the signed correlation criterion, and the fault detection index is calculated to discriminate the internal faults from other events. In addition, a new online technique is introduced to adjust the protection settings considering the different output power levels of the WF. The conducted PSCAD/EMTDC simulation studies confirm the acceptable performance of the proposed protection algorithm for numerous normal and fault scenarios, including different fault resistances and inception angles as well as all fault types. The effect of line length, type of wind turbine generator, and different values of WF output power are also considered.
Over the last few decades, many developing countries witnessed remarkable growth that resulted in progress and prosperity across various sectors. However, such growth impacted the work-related safety accidents in terms of occurrence and/or severity. To mitigate health and safety risks, governments issued and enforced legislative regulations targeting general and specific industries. Nevertheless, the impact of these regulations in some industry sectors warrants further investigation. The aim of this study is to identify work-related accident hazards in the United Arab Emirates (UAE) and examine causal factors to provide recommendations for improvement. Content analysis of accident reports and confirmatory factor analysis (CFA) are the two main research tools used in this study. Content analysis is conducted based on a sample of 1700 historical accident reports occurred during 2019–2020 in UAE. The CFA is conducted based on a survey developed using the accident reports analysis and feedback from six experts with 290 respondents. The analysis revealed that falls, injuries due to contact with sharp edges, and burns are the most frequent accident types. The CFA analysis revealed that training enhancement and total safety operating system are viable solutions to aid in controlling the frequency and severity of these accidents.
For any bounded and convex set Ω⊂RN\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\Omega \subset {\mathbb {R}}^{N}$$\end{document} (N≥2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$N\ge 2$$\end{document}), with smooth boundary ∂Ω\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\partial \Omega$$\end{document}, and any real number p>1,\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$p>1,$$\end{document} we denote by up\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$u_{p}$$\end{document} the p-torsion function on Ω\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\Omega$$\end{document}, that is the solution of the torsional creep problemΔpu=-1\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\Delta _{p}u=-1$$\end{document} in Ω\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\Omega$$\end{document}, u=0\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$u=0$$\end{document} on ∂Ω\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\partial \Omega$$\end{document}, where Δpu:=div(∇up-2∇u)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\Delta _{p}u:=div( \left| \nabla u\right| ^{p-2}\nabla u)$$\end{document} is the p-Laplace operator. Our aim is to investigate the monotonicity with respect to p for the p-torsional rigidity on Ω\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\Omega$$\end{document}, defined as TpΩ:=∫Ωupdx\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$T_{p}\left( \Omega \right) :=\int _{\Omega }u_{p}dx$$\end{document}. More precisely, we show that there exist two constants D1∈12,e-1N+1\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$D_1\in \left[ \frac{1}{2},e^{\frac{-1}{N+1}}\right]$$\end{document} and D2∈1,N\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$D_2\in \left[ 1,N\right]$$\end{document} such that for each bounded and convex set Ω⊂RN\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\Omega \subset {\mathbb {R}}^{N}$$\end{document} with |∂Ω||Ω|≤D1\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\frac{|\partial \Omega |}{|\Omega |}\le D_1$$\end{document} the function p→Tp(Ω)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$p\rightarrow T_p(\Omega )$$\end{document} is decreasing on 1,∞\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\left( 1,\infty \right)$$\end{document}, while for each bounded and convex set Ω⊂RN\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\Omega \subset {\mathbb {R}}^{N}$$\end{document}, with |∂Ω||Ω|≥D2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\frac{|\partial \Omega |}{|\Omega |}\ge D_2$$\end{document}, the function p→Tp(Ω)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$p\rightarrow T_p(\Omega )$$\end{document} is increasing on 1,∞\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\left( 1,\infty \right)$$\end{document}. Moreover, for each real number s∈(D1,D2)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$s\in (D_1,D_2)$$\end{document} there exists a bounded and convex set Ω⊂RN\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\Omega \subset {\mathbb {R}}^{N}$$\end{document}, with |∂Ω||Ω|=s\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\frac{|\partial \Omega |}{|\Omega |}=s$$\end{document}, such that the function p→Tp(Ω)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$p\rightarrow T_p(\Omega )$$\end{document} is not monotone on (1,∞)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$(1,\infty )$$\end{document}.
Chemical waste constitutes a group of environmental pollutants including pesticides, heavy metals, hormones, pharmaceuticals, and healthcare products that are widely distributed in our environment due to their wide use in various human activities. The presence of these compounds within local communities and ecosystems has drawn significant interest in improving the detection and bioremediation efforts of these compounds. Since these pollutants are highly mobile and stable under ambient conditions, there is a need to detect such pollutants in water and soil samples as an initial step that helps to eliminate their effect through adsorption or photocatalytic degradation processes. This review aims to highlight the origin of these pollutants and recent advancements in available analytical tools to detect such pollutants in environmental samples with a focus on pesticides, hormones, and pharmaceutical products. The environmental ecosystems of focus in this review involve soil, groundwater, and freshwater ecosystems. Various extraction and other pretreatment processes were also highlighted with a major focus on methods reported to decontaminate and help the environment through photocatalytic degradation of these pollutants under various conditions. Graphical abstract
Micro-power generators are increasingly becoming popular to meet the power requirements of micro-electromechanical systems, such as small sensors. One such resource of harnessing energy is through exploiting flow instabilities found in vortex-induced vibrations, flutter, etc. In this work, we numerically investigate the hydrodynamic performance of fully forced flapping foils with the goal to exploit their underlying physical mechanisms for the development of micro-power generators. We consider prescribed combination of plunging and pitching motions imposed to a NACA-0012 airfoil. We conduct a parametric study by varying the Strouhal number and the amplitude of the pitching angle to identify two operational flow regimes: power generation and thrust-producing propulsion using the feathering criterion. In the latter regime, the foil performs positive work on the surrounding fluid and therefore, the positive propulsive efficiency can be attained as long as the horizontal hydrodynamic force remains negative. For the power generation regime, the product of the lift force and plunging velocity is found mostly positive over the oscillating cycle, which indicates that the flowing fluid carries out work on the foil. The parametric study reveals that the foil can reach up to 42% power generation efficiency when setting the pitching amplitude in the range of 60° to 70°. For foils operating in the power generation regime, we present a piezoelectric energy harvester that can efficiently harness usable electric power from high fluid pressure regions. We identify two core locations based on the pressure field at which the attachment of piezoelectric patches can lead to significant energy harvesting. As such, the present study provides guidance for the design enhancement of micro-power generators relying on the interactions of flapping foils with the surrounding fluid.
Nanotechnology is a rapidly growing industry where nanomaterials are used in almost every field, including electronics, cosmetics, engineering, household products, biotechnology and medicine. Nanoparticles (NPs) have unique physical and chemical properties, which may cause potential hazards to human health, especially with constant exposure. Various studies have shown that NPs can enter the human body either through the respiratory tract, dermal absorption or via the gastrointestinal system and have the potential to cause respiratory disorders, behavioral changes, neurological disorders, as well as cancer. This review focuses on the health implications of NPs, specifically gold, silver, silica, titanium dioxide, aluminum, aluminum oxides, metal organic frameworks (MOF), aerosol particles, flame retardants, quantum dots, and carbon nanotubes. Herein, we discuss the routes of exposure and the impact of these nanoparticles on human health. We also summarize in-vitro and in-vivo studies that analyze the cytotoxicity profile and the associated health impact of these nanoparticles. This study could be utilized to develop well-defined guidelines for setting exposure limits for different NP types as well as a summary of related characteristics such as size, shape, morphology, and surface charge.
Biofuel cells (BFCs) convert biochemical energy into electrical energy by virtue of the biocatalyst component. They incorporate bio-catalysts composed of microorganisms and enzymes. BFCs are considered among the novel technologies for the production of potable water/electricity and self-powered biosensors simultaneously. However, BFCs, still suffer from various drawbacks, namely, the short lifetime, difficulty in optimizing the optimum operating conditions (substrate concentration and pH), and designing electrodes of sufficient surface area, hence, leading to low power densities and reduced columbic efficiencies. The utilization of nanomaterials in the bioelectrode construction of BFCs has been proposed and demonstrated promising improvement in performance, including electron transfer, thermal and mechanical stability, and conversion efficiency. The use of nanomaterials in bio-electrodes provided large active surface areas between enzymes/electrodes, thus, improving electron kinetics. Carbon-based nanostructures in particular, i.e., carbon-based nanomaterials such as graphene/fullerenes/carbon nanotubes (CNTs)/carbon nanofibers (CNFs), conducting polymers/composites, and metallic nanoparticles/oxides have been extensively investigated. These studies highlighted the progress made in the use of nanomaterials/enzymatic immobilizations for improving the performances of electrodes. Challenges and opportunities related to the stability and durability of BFCs for long-term applications have been discussed for future development directions. Furthermore, recommendations on novel designs of nanomaterials possessing good electrical properties, optimized porous matrix, and ease of separation in nanomaterials/enzymes systems have been discussed for green energy production.
Artificial islands near Dubai were constructed with geomaterials of significant gravel content from other areas of the United Arab Emirates (UAE). The fills were dynamically compacted and their present geotechnical properties are unknown. Large development projects are being proposed on the islands that will require extensive field testing to characterize the fills because existing correlations developed for nearby natural soils are not representative. The main focus of this study is to develop correlations between Standard Penetration Test (SPT), Cone Penetration Tests (CPT), and shear wave velocity (Vs) measurements applicable to the compacted fills with high gravel content. More than fifty (50) SPT and similar number of CPT tests are performed on a large area of the island. A number of Multi-Channel Analysis of Surface Waves (MASW) and Downhole Seismic (DHS) tests are conducted to measure the distribution of Vs with depth and imaging. The data is analyzed to develop correlations between SPT and CPT and between SPT and Vs. The proposed correlation between SPT and CPT generally does not agree with existing correlations for coarse grained soils. This study predicts larger values of tip resistance (qc) with N60 values. The predicted Vs values as function of N60; however, are comparable with some prediction equations in the literature. The Vs values from MASW and DHS for the fill are comparable on average; however, reliability of DHS increases with depth. The results from all tests reveal the inadequacy of earlier dynamic compaction in achieving consistent and uniform densification.
In this article, a bimatrix gamma distributions is introduced. Various mathematical properties of the proposed distribution like marginal distributions, expected values, entropies, and moment generating function are derived. Also, distributions of sum, quotient, and product are investigated. Parameter estimation by the method of maximum likelihood is considered. A simulation study is performed to check the finite sample performance of the maximum likelihood estimators.
This paper examines the energy separation in vortex tubes which is a passive device that can split a pressurized room temperature gas stream to hot and cold streams. The paper employs numerical simulations to investigate the impact of various working fluids such as helium, air, oxygen, nitrogen, and carbon dioxide on the energy separation in the vortex tube, using the SST $$k{-}\omega$$ k - ω turbulence model with viscous heating. A three-dimensional numerical investigation is sued to examine the effect of a single fluid property on vortex tube performance, while keeping the rest of the fluid properties unchanged, which is impossible to achieve via experimental study. The numerical investigation examines the influence of molecular weight, heat capacity, thermal conductivity, and dynamic viscosity on energy separation. The results show that energy separation performance improves with lower molecular weight and heat capacity, and higher dynamic viscosity of the working fluids, while no impact of the thermal conductivity is observed. Out of five gases tested in this study, helium has yielded the maximum temperature separation, while carbon dioxide has yielded the lowest performance. Results show that viscous dissipation contributes to the temperature separation in vortex tube.
Removal efficiency of gold from a solution of pure tetrachloroaurate ions was investigated using microbial fuel cell (MFC) technology. The effects of type of catholyte solution and initial gold concentration on the removal efficiency were considered. Due to its presence at high levels in the gold wastewater, the effect of copper ions on the removal efficiency of the gold ions was also studied. The effects of pH and initial biomass concentration on the gold removal efficiency was also determined. The results showed that after 5 h contact time, 95% of gold removal efficiency from a wastewater containing 250 ppm of initial gold ions at ambient temperature using 80 g/L yeast concentration was achieved. After 48 h of the cell's operation under the same condition, 98.86% of AuCl4– ions were successfully removed from the solution. At initial gold concentration in the waste solution of 250 ppm, pH 2, and initial yeast concentration of 80 g/L, 100% removal efficiency of the gold was achieved. On the other hand, the most suitable condition for copper removal was found at a pH of 5.2, where 53% removal efficiency from the waste solution was accomplished.
We use a sample of Swift and Fermi short gamma-ray bursts (SGRBs) to test the validity of the Amati and Yonetoku correlations, which were originally found for long bursts. The first relation is between Ep,i\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$E_{p,i}$\end{document}, the intrinsic peak energy of the GRB prompt emission, and Eiso\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$E_{\mathit{iso}}$\end{document}, the equivalent isotropic energy. The second relationship is between Ep,i\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$E_{p,i}$\end{document} and Liso\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$L_{\mathit{iso}}$\end{document}, the peak isotropic luminosity. The sample is composed of 36 Swift SGRBs and 15 Fermi SGRBs that have measured redshifts and whose spectral parameters, with their uncertainties, are available online. The uncertainties (error bars) on the values of the calculated energy flux P, of the energy Eiso\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$E_{\mathit{iso}}$\end{document}, and of the peak isotropic luminosity peak Liso\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$L_{\mathit{iso}}$\end{document} are estimated using a Monte Carlo approach. We find that SGRB energy and luminosity quantities (Ep,i\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$E_{p,i}$\end{document}, Liso\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$L_{\mathit{iso}}$\end{document}, and Eiso\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$E_{\mathit{iso}}$\end{document}) can be correlated with Amati- and Yonetoku-like relations reasonably well (Pearson r-values of 0.5 and 0.6, respectively), although the data shows large scatter and hence large error bars on the slope and the intercept of the fitting line. Our results are consistent with other similar works, though we here use the largest sample of SGRBs with redshifts so far on this topic. We also find that Eiso\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$E_{\mathit{iso}}$\end{document} and Liso\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$L_{\mathit{iso}}$\end{document} seem to evolve with redshift as (1+z)4.9±0.3\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$(1+ z)^{4.9 \pm 0.3}$\end{document} and (1+z)5.5±0.9\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$(1+z)^{5.5\pm 0.9}$\end{document}, respectively, with a moderate goodness of fit. However, we caution that this is probably due to selection effects rather than being a genuine redshift evolution of Eiso\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$E_{\mathit{iso}}$\end{document} and Liso\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$L_{\mathit{iso}}$\end{document}.
Language teaching has been described as a “profession in crisis”; a situation likely worsened by the effects of an emergency conversion to online teaching during the COVID-19 pandemic. The present study examines two waves of data (from April and November 2020) on stress, coping, and well-being during those eight months. Results show increase in teachers' stress associated with health and travel but decreases in stress due to online teaching and the shortage of goods in retail stores. There was a significant reduction in coping behavior as teachers settled into the new normal. Well-being, as measured by PERMA, declines significantly, and there was a significant increase in sadness, loneliness, and anger. However, teachers reported an increasing sense of growth during trauma. Time 2 data included a measure of hope, defined by feelings of agency and available pathways to goal achievement. Rarely has hope been studied among teachers in general or language teachers in particular. Results show significant, positive correlations between hope and various measures of successful coping and teacher well-being, including a sense of growth over time. The study suggests the time frame of the study was especially difficult for teachers, but that hope is associated with more positive outcomes.
Genuineness of smiles is of particular interest in the field of human emotions and social interactions. In this work, we develop an experimental protocol to elicit genuine and fake smile expressions on 28 healthy subjects. Then, we assess the type of smile expressions using electroencephalogram (EEG) signals with convolutional neural networks (CNNs). Five different architectures (CNN1, CNN2, CNN3, CNN4, and CNN5) were examined to differentiate between fake and real smiles. We transform the temporal EEG signals into normalized gray-scale images and perform three-way classification to classify fake smiles, genuine smiles, and neutral expressions in the form of subject-dependent classification. We achieved the highest classification accuracy of 90.4% using CNN1 for the full EEG spectrum. Likewise, we achieved classification accuracies of 87.4%, 88.3%, 89.7%, and 90.0% using Beta, Alpha, Theta, and Delta EEG bands respectively. This paper suggests that CNNs models, widely used in image classification problems, can provide an alternative approach for smile detection from physiological signals such as the EEG.
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