Auger Spectra and Different Ionic Charges Following 3s, 3p and 3d Sub-Shells Photoionization of Kr Atoms

The decay of inner-shell vacancy in an atom through radiative and non-radiative transitions leads to final charged ions. The de-excitation decay of 3s, 3p and 3d vacancies in Kr atoms are calculated using Monte-Carlo simulation method. The vacancy cascade pathway resulted from the de-excitation decay of deep core hole in 3s subshell in Kr atoms is discussed. The generation of spectator vacancies during the vacancy cascade development gives rise to Auger satellite spectra. The last transitions of the de-excitation decay of 3s, 3p and 3d holes lead to specific charged ions. Dirac-Fock-Slater wave functions are adapted to calculate radiative and non-radiative transition probabilities. The intensity of Kr^{4+} ions are high for 3s hole state, whereas Kr^{3+} and Kr^{2+} ions have highest intensities for 3p and 3d hole states, respectively. The present results of ion charge state distributions agree well with the experimental data.Comment: Published in SIGMA (Symmetry, Integrability and Geometry: Methods and Applications) at http://www.emis.de/journals/SIGMA

A Study of Islamic and Arab Markets\u27 Role in Revitalizing Urban Spaces

Market places have occupied a major role in most cities around the world, being a site for more than just economic interactions, but rather a cultivating agent for social and cultural growth. The Arab and Islamic cities have a proud history of market places, most of the times being the main core of the city, with urban development encompassing it, and till the present day market places are in the heart of most communities. The modern city brought with it a devaluing of the traditional market places, making it a tourist attraction as in the case of "khan el Khalil",or leaving it to rust like "bab el louq" market. Those markets while playing a big role historically, modern city planning moved the services and markets into other form, thus becoming less important, abandoned, or even demolished at cases.The issue at hand deals with how the contemporary urban planning affected market places, with emphasis on closed markets (Bab el-louk)which can be said to be the successor of the ancient Bazaar or Wekala. Bal el-Louk market was once in the heart of Cairo and vital part of its community life, but now the market after more than a 100 years, is in ruins, but hope is not yet all lost, since the market can still be revived and revitalized.To tackle this issue a combination of comparative and field studies must occur. On the one hand, comparative studies with markets in the US or closed markets in European cities such as Paris or Copenhagen would be done to find the necessary elements and goals that would make those markets vital, and the necessary steps to revitalize our own forgotten markets. The other study would have to deal with the current condition of bab el louk market in Cairo, finding out the reason behind its demise, the owners and users feedback on said market, and the opportunities for change.With the results of the studies, general recommendations would be made for the revitalization of the Egyptian marketplaces, using an urban framework that would lead to those markets be available for costumers again and back to playing their major cultural and social rule

ADVANCED AMPLITUDE CENTERING AS AN INVIGORATING MANIPULATION FOR UNIFIED WAVELENGTH SPECTRAL RESOLUTION OF TERNARY MIXTURES

Objective: This work presented the novel spectrophotometric approach namely, advanced amplitude centering (AAC). The method was applied for the resolution of ternary mixtures with partially or completely overlapped spectra.Methods: Advanced amplitude centering was based on the determination of ternary mixtures using single divisor where the concentrations of the components are determined through progressive manipulation performed on the same ratio spectrum. The centered amplitude at unified wavelength was resolved and applied for the determination of three components with partially and severely overlapped spectra. The work discussed the applications and advantages of the novel univariate advanced amplitude centering compared to the chemometric model, partial least square (PLS).Results: The specificity of the proposed methods was checked using laboratory-prepared mixtures of amlodipine (AML), valsartan (VAL) and hydrochlorothiazide (HCT) and was successfully applied for the analysis of two pharmaceutical formulations. The validity of results was assessed by applying the standard addition technique.Conclusion: The results obtained were found to agree statistically with those obtained by a reported method, showing no significant difference with respect to accuracy and precision

Risk factor assessment of digital eye strain during the COVID-19 pandemic: a cross-sectional survey

Background: Shifting to online learning during the coronavirus pandemic has increased the number of individuals symptomatic of digital eye strain (DES). This study aimed to determine the frequency and potential risk factors of DES among university staff members and students in this pandemic era. Methods: A cross-sectional online survey was conducted during the pandemic, in May and June 2020. The online questionnaire was designed to collect data on DES-related ocular and extraocular manifestations. The survey was sent via social media to the previous year’s students and staff within the Faculty of Medicine, Tanta University, Tanta, Egypt. The responses were downloaded and analyzed. Results: Of the 412 participants completing the questionnaire, 34 (8.3%) were university staff members with a mean (standard deviation [SD]) age of 36.7 (6.6) years, and 378 (91.7%) were university students with a mean (SD) age of 20.8 (1.8) years. Participants with DES symptoms numbered 294 (71.4%) before the lockdown, increasing to 366 (88.8%) during the last month, with 84 developing new-onset DES. Most participants reported ocular symptoms associated with DES. After the lockdown, both students and staff had a significant prolongation of nighttime digital screen use and TV watching, an increase in the 4-item Patient Health Questionnaire (PHQ-4) severity scale scores, and anxiety and depression, with a reduced duration of daytime reading (all P < 0.05). Students had a significant prolongation of daytime digital screen use and TV watching and an increase in the frequency of eye lubricant use and mean Perceived Stress Scale (PSS)-4 scores (all P < 0.05). Multiple logistic regression analysis revealed that studenthood and increased nighttime screen use were independent risk factors for DES by odds ratios (95% confidence intervals) of 10.60 (2.12 – 53.00) and 3.99 (1.71 – 9.34), respectively (both P < 0.05). Conclusions: Lockdown and closure of the university, with a shift to online learning, increased the exposure of staff and students to digital screens and the number of individuals with DES. Studenthood and prolonged nighttime digital screen use were independent risk factors for DES. Further studies investigating the prevalence and risk factors of DES, comparing similar data during and after the pandemic, may reveal other aspects of DES caused by virtual reality-based training

Acquired symptomatic external punctal stenosis: A tertiary referral center study

Background: To report the prevalence of acquired symptomatic external punctal stenosis (EPS) in a tertiary referral center in Kuwait, and to study the associated risk factors, etiologies, and management outcomes. Methods: This prospective interventional hospital-based study was performed at the Farwaniya governmental hospital in Kuwait between November 2018 and November 2019. All patients were referred to the oculoplastic clinic with symptomatic epiphora, age > 18 years, epiphora Munk score equal or more than 0, tear film meniscus equal or more than 2 mm, and punctum with a grade equal or less than 2 (smaller than normal size, but recognizable) were included. Exclusion criteria were congenital causes of epiphora, previous eyelid surgeries, and traumatic or neoplastic causes of punctal or canalicular obstruction. Results: A total of 418 patients with symptomatic epiphora, who were referred to our oculoplastic clinic, were enrolled in our study. The prevalence of EPS was 70.3%. Examination of the puncta revealed different shapes, including tangential, pinpoint, elevated, slit-shaped, horse shoe-shaped, and membranous puncta, with the tangential type accounting for the greatest proportion (65.3%). Bilateral punctal stenosis was observed in 206 patients (70.1%) and unilateral involvement in 88 patients (29.9%). Dilatation and syringing were performed for all puncta upon diagnosis, and repeated dilatation was performed for 225 puncta (32.7%). Placement of a Mini-Monoka tube was performed in 11 puncta (1.6%). Conclusion: EPS was a common cause of symptomatic epiphora in our study. Aging and female sex were identified as common risk factors. Most etiological factors of EPS were associated with a pathophysiological inflammatory mechanism. For exact estimates of its prevalence, a population-based study is necessary in future

Design PV system for a small GEO satellite and studying the effect of using different types of propulsion

This paper presents an optimum design of the solar Photo-Voltaic (PV) power system for small Geostationary Earth Orbit (GEO) satellites using triple junction solar cells and advanced Lithium Ion batteries. The paper applies the proposed system on various propulsion technologies; full chemical, full electrical and hybrid propulsions. This research work studies the capability to fulfil efficiently all the satellite power requirements during both the launching and the on-station phases while reducing the high cost challenge. Since the propulsion type is a key factor for the satellite cost, an economic analysis is demonstrated and investigated in two different strategies. The first scenario fixes the satellite weight and offers the revenue due to the increase in the satellite payload. However, the second scenario evaluates the saving profits due to the reduction in the satellite weight using the same number of satellite transponders. The analytical comparison among the different propulsion techniques shows the superior advantages of using the full electrical satellites. 

Review of Recommender Systems Algorithms Utilized in Social Networks based e-Learning Systems & Neutrosophic System

In this paper, we present a review of different recommender system algorithms that are utilized in social networks based e-Learning systems. Future research will include our proposed our e-Learning system that utilizes Recommender System and Social Network. Since the world is full of indeterminacy, the neutrosophics found their place into contemporary research. The fundamental concepts of neutrosophic set, introduced by Smarandache in [21, 22, 23] and Salama et al. in [24-66].The purpose of this paper is to utilize a neutrosophic set to analyze social networks data conducted through learning activities

LABORATORY COMPARISON BETWEEN TWO COMMERCIAL FUNGI COMPOUNDS AND TWO ISOLATES OF ENTOMOPATHOGENIC FUNGI, ON PUPAE OF THE COTTON LEAFWORM Spodoptera littoralis (BOISD.) (LEPIDOPTERA: NOCTUIDAE)

The pupae of the cotton leafworm Spodoptera littoralis (Boise.) (Lepidoptera: Noctuidae), a pest affecting many economic crops were treated with two commercial fungi compounds and two isolates of entomopathogenic fungi, by applying the pupal dipping technique. Results showed that all of the tested entomopathogenic fungi adversely affected the adult emergence, Suspensions (1x108 spores /ml)    of conidia harvested from M. anisopliae isolate resulted in the highest mortality (62%) followed by B. bassiana isolate (60%) than M. anisopliae commercial (51%) and the lowest mortality (49%) with B. bassiana commercial, the treatment also led to reducing the egg-laying capacity and egg hatchability. Treatment with these entomopathogenic fungi also caused several malformations in pupae and adults resulting from the treatment of pupae. Conclusion of our results that the two tested entomopathogenic fungi isolate M. anisopliae and B. bassiana was efficient and can be recommended as bio-insecticides to control the cotton leafworm S. littoralis, within the integrated pest management (IPM) program

A Mechanistic Approach to Crystallite Length as Related to Cell-Wall Structure

A tentative mechanistic model is proposed that relates variation in crystallite length in wood to some physical conditions under which the crystallite may have been formed, namely the curvature and ultrastructure of the microfibril. Over most of the experimental data range, representing both hardwood and softwood samples, the model allows reasonably good prediction of the effect of crystallite orientation angle and radial distance from the cell center. As the angle increases and radial distance decreases, the average crystallite length becomes smaller