Sediment Yield Problems in Khassa Chai Watershed Using Hydrologic Models

Upland erosion and sedimentation are one of the severe problems which faces dams as sediments occupy spaces within reservoirs storage, hence, decreasing live water storage which is the main purpose of dam’s construction. Iraq is one of the countries that will face a significant shortage of water income as a result of both the increment in water demand and of the reduction of water shares from the source countries. Thus, the existing dams in Iraq represent a strategic resource to fulfill water demands, and the sedimentation at these dams is studied to assess the quantity of sediments that reach to these reservoirs and decrease available water volume and useful life of reservoir. In the current study, Khassa Chai Dam is located in the Northeast of Iraq and its main watershed basin covers an area of about 412 km2 between Kirkuk and Al Sulaymaniyah Governorates has been selected to estimate and predict the amount of sediment yield based on 30 years of daily climate data and the events of different intensity rainstorms. Automated geospatial watershed assessment (AGWA) tool model has been used to simulate Khassa Chai Dam catchment area. This model utilizes the geographic information system (GIS) application to analyze the required data from GIS layer for digital elevation model, soil type, land use, and land cover by interference with the required climate data. The key components of AGWA model are the soil and water assessment tool model and kinematic runoff and erosion (KINEROS) model which are able to simulate complex watershed behavior to explicitly account for spatial variability of soils, rainfall distribution patterns, and vegetation. The hydrologic characteristics for Khassa Chai catchment area according to the SWAT outputs show that the most erosive sub-basins are not able to deliver the eroded material or sediments to the reservoir due to their transmission losses, percolation, and other minor obstacles. KINEROS model simulation for sediment yield is much closer to the behavior of Khassa Chai watershed in erosion and sediment transport according to the single storm events and for individually selected sub-watersheds which are closed in their location to reservoir inlet

Mott scattering at the interface between a metal and a topological insulator

We compute the spin-active scattering matrix and the local spectrum at the interface between a metal and a three-dimensional topological band insulator. We show that there exists a critical incident angle at which complete (100%) spin flip reflection occurs and the spin rotation angle jumps by $\pi$. We discuss the origin of this phenomena, and systematically study the dependence of spin-flip and spin-conserving scattering amplitudes on the interface transparency and metal Fermi surface parameters. The interface spectrum contains a well-defined Dirac cone in the tunneling limit, and smoothly evolves into a continuum of metal induced gap states for good contacts. We also investigate the complex band structure of Bi$_2$Se$_3$.Comment: published versio

The reincarnation of work motivation: Millennials vs older generations

Abstract: This study examines generational differences in valuing the sources of motivation in workplace behaviour between millennials and older generations, with a view to assist managers in making employment decisions and maintaining multigenerational staff in the services sector. Based on systematically sampled data, the authors used Gagné et al.’s Multidimensional Work Motivational Scale (MWMS) to measure the different facets of work motivators alongside a three-item measure of employee overall work motivation (designed for this study) to address the hypotheses. Using structural equation modelling procedures to analyse the data, the authors found that four out of six motivators regress differently to overall work motivation. In other words, both extrinsic regulation–material and identified regulation are valued more by millennials compared to older generations, while extrinsic regulation–social and introjected regulation are valued less by millennials compared to older generations. Résumé Dans cette étude, nous analysons les différences générationnelles d’appréciation des sources de motivation dans le comportement au travail entre la génération des millénials et les générations plus âgées, dans l’objectif d’aider les gestionnaires à prendre des décisions en matière d’embauche et à maintenir des équipes multigénérationnelles dans le secteur des services. À partir de données ayant fait l’objet d’un échantillonnage systématique, nous avons utilisé l’Échelle multidimensionnelle de la Motivation au Travail (MWMS) de Gagné et al. (2015) pour mesurer les différents aspects des facteurs de motivation au travail, ainsi qu’une échelle de mesure en trois points de la motivation globale des employés au travail (conçue pour cette étude) pour examiner les hypothèses formulées. En utilisant des modèles d’équations structurelles, nous avons constaté que quatre des six facteurs de motivation pèsent différemment sur la motivation globale au travail : la régulation extrinsèque (matérielle) et la régulation identifiée sont plus valorisées par les millénials que par les générations plus âgées, tandis que la régulation extrinsèque (sociale) et la régulation introjectée sont moins valorisées par les millénials que par leurs aînés. Resumen Este artículo analiza las diferencias generacionales en la valoración de las fuentes de motivación en el comportamiento en el trabajo entre la generación de los millenials y las generaciones mayores, con el objetivo de ayudar a los gerentes a tomar decisiones de reclutamiento y mantener una plantilla multigeneracional en el sector servicios. Usando datos muestreados sistemáticamente, se utiliza la Escala de Motivación Laboral Multidimensional (MWMS) de Gagné et al. (2015) para medir las diferentes facetas de los motivadores laborales junto con una medida de 3 ítems de la motivación laboral general de los empleados (diseñada para este estudio) para abordar las hipótesis formuladas. Utilizando modelos de ecuaciones estructurales, se ha hallado que cuatro de los seis motivadores tienen un peso diferente sobre la motivación laboral general. Tanto la regulación extrínseca (material) y la regulación identificada son más valoradas por los millennials en comparación con las generaciones anteriores, mientras que la regulación extrínseca (social) y la regulación introyectada son menos valoradas por los millennials que por las generaciones anteriores

Investigation of optical and electrical properties of Cobalt-doped Ge-Sb-S thin film

Amorphous Germanium Antimony Sulphide (Ge-Sb-S) doped with Cobalt (Co) have been deposited on glass substrates by thermal evaporation technique on a glass substrate. The films deposited onto glass substrates are characterized by Energy Dispersive X-ray Fluorescence Spectrometer, UV–VIS spectrophotometer, Raman spectroscopy, and Capacitance-Voltage Keithley meter. The optical band gap was calculated from the UV–Visible spectrum and found to be 2.05 eV. Raman spectroscopy measurements reveal that a wide band spectrum from 300 to 410 cm−1 centered at 355 cm−1. The Raman shift peaks at 325 cm−1 and 350 cm−1 are as-signed to the bond stretching mode Sb-S and Ge-S, respectively. In addition, from the obtained Raman spectra it is concluded that the presence of Co doped with Ge-Sb-S. The capacitance and conductance versus voltage measurements were performed at different temperatures. The results show a slight increase in the capacitance with temperature and it reaches a maximum value around 150 °C, and eventually it becomes negative. This behavior is interpreted in terms of the nucleation growth process and the thermally activated conduction process with measured activation energy of 0.79 eV.This work is funded by the University Program for Advanced Research - United Arab Emirates University , (project no. 31S313 ).Scopu

Compact Tri-Band Notched Characteristics UWB Antenna for WiMAX, WLAN and X-Band Applications

Compact microstrip-fed printed monopole antenna with triple band-notched characteristics is suggested for ultra-wideband (UWB) applications. The antenna is constructed of a conventional rectangular microstrip patch antenna with partial ground plane and T-shaped strip employed in the ground plane as well as an inverted Ω- and L-shaped slots incorporated within the radiated element. The notched functions are created by the inverted Ω- and L-shaped slots, which are realized for WiMAX (from 2.69 to 4.5 GHz) and WLAN (from 5.49 to 6.37 GHz). The T-shaped parasitic strip generates the third notch for the X-band uplink satellite communication (from 8.15 to 9.61 GHz). The measured operating -10 dB bandwidth of the proposed antenna extends from 2.39 to more than 18 GHz except at the notched bands. The prototype antenna has a total area of 20×20×1.6 mm3. Electromagnetic (EM) simulations are carried out using 3D full-wave FEM-based simulator. EM simulation results are in good agreement with measurement results. The radiation pattern of the proposed antenna is nearly Omni-directional over the whole targeted band

Who’s more vulnerable? A generational investigation of COVID-19 perceptions’ effect on Organisational citizenship Behaviours in the MENA region: job insecurity, burnout and job satisfaction as mediators

Background This paper is an empirical investigation that examines a path model linking COVID-19 perceptions to organisational citizenship behaviour (OCBs) via three mediators: job insecurity, burnout, and job satisfaction. The research examines the path model invariance spanning Generations X, Y, and Z. Three countries in the Middle East and North Africa (MENA) were the focus of the study. Methods The data was collected from a sample of employees in service companies (n = 578). We used a Partial Least Square Structural Equation Modelling (PLS-SEM) to analyse the data. Results Our findings reveal that COVID-19 perceptions positively predict job insecurity, which positively impacts burnout levels. Burnout negatively predicts job satisfaction. The findings established that job satisfaction positively predicts OCBs. The mediation analysis determined that job insecurity, burnout and job satisfaction convey the indirect effects of COVID-19 perceptions onto OCBs. Finally, our hypothesised model is non-equivalent across Generations X, Y and Z. In that regard, our multi-group analysis revealed that the indirect effects of COVID-19 perceptions on OCBs were only valid amongst younger generations, i.e., Generation Y and Generation Z. Specifically, younger generations are substantially more vulnerable to the indirect effects of COVID-19 perceptions on their engagement in OCBs than Generation X whose job satisfaction blocks the effects of COVID-19 perceptions on OCBs. Conclusions The present study extends our knowledge of workplace generational differences in responding to the perceptions of crises or pandemics. It offers evidence that suggests that burnout, job attitudes and organisational outcomes change differently across generations in pandemic times

Kaposi sarcoma in an HIV-negative Tunisian patient: A rare cause of metatarsalgia

AbstractBackgroundKaposi sarcoma (KS) is an angioproliferative neoplasm that is commonly associated with human herpes virus-8 (HHV-8) and human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS). KS with osseous involvement is a rare occurrence, and is far more common in acquired immunodeficiency syndrome (AIDS)-related KS.Case presentationWe present a 32-year-old Tunisian man, HIV negative, who presented with a 4-year history of atraumatic mechanical metatarsalgia that progressively worsened with a limping gait. Physical examination revealed marked symmetrical forefoot lymphedema and a painful restricted left knee joint movement. Physical examination showed purple-blue plaques and nodules on the feet and ankles. Serologic tests for HIV and syphilis were negative. Plain radiography of the feet revealed numerous small lytic lesions. There were also scattered lytic lesions in the metaphysis of the proximal tibia and fibula. Osteolysis was predominantly left. Magnetic resonance imaging of the feet showed abnormal bone marrow signal of metatarsals and phalanges. Skin lesion biopsy yielded the diagnosis of Kaposi sarcoma. The disease was managed with chemotherapy including vinblastine.ConclusionIn a patient presenting with metatarsalgia without a commonly detected cause, it is mandatory to search for other lesions that may point to a rare diagnosis as KS which is famous for involvement of the metatarsal bone

Pandemic pains to Instagram gains! COVID-19 perceptions effects on behaviours towards fashion brands on Instagram in Sub-Saharan Africa: Tech-native vs non-native generations

This study represents a novel attempt to investigate the cascading effects of COVID-19 perceptions onto behavioural patterns towards fashion brands on Instagram and across two generations tech-native vs tech non-native) in a Sub-Saharan African context. We drew our study on a sample of 338 Instagram users that experienced fashion brands on Instagram in two Sub-Saharan African countries: Uganda and Nigeria. We used partial least square structural equation modelling (PLS-SEM) to test the hypothetical model. We found that COVID-19 perception positively predicted enjoyment and usefulness, leading to more satisfaction with fashion brand accounts on Instagram and hence greater intention to follow and recommend those accounts. Finally, running a multigroup analysis (MGA), we found the effects of COVID-19 perceptions pronounced into both intentions to follow and intention to recommend via the sequence of mediators: enjoyment and satisfaction were only valid amongst the tech-native generational cohort. Our research suggested a new generational categorisation based on technology nativity – offering a new direction of generational studies in digital marketing communications

Nanoparticles Synergistic Effect with Various Substrate Pretreatment and their Comparison on Biogas Production from Algae Waste

Algae waste is one of the potential substrates for biogas and biohydrogen production and can comprehend multiple benefits of waste treatment and resource utilization. In view of the key bottlenecks such as low substrate degradation rate and poor productivity of algae waste production process, this study analyzes the combined effect of two metallic and metallic oxide nanoparticles with different substrate pretreatment methods (autoclave, ultrasonic, and microwave methods) to investigate the effect of anaerobic digestion of green algae (Enteromorpha). The results showed that out of the three pretreatment methods, microwave pretreatment and nanoparticles' synergistic effect significantly increases biogas production. The microbial community composition at the phylum level was analyzed. It was observed that the Firmicutes were most abundant across all samples. The relative abundance of Firmicutes for control, Ni NPs + MW, Co NPs + MW, and Fe3O4 NPs + MW groups were 51.78, 70.37, 75.77, and 83.93%,      respectively. The second most abundant was of Bacteroidetes that also contributes to hydrogen production. This relatively high abundance of Firmicutes and Bacteroidetes promises its potential applications in a hydrogen production facility. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Phase Transition in a Random Fragmentation Problem with Applications to Computer Science

We study a fragmentation problem where an initial object of size x is broken into m random pieces provided x>x_0 where x_0 is an atomic cut-off. Subsequently the fragmentation process continues for each of those daughter pieces whose sizes are bigger than x_0. The process stops when all the fragments have sizes smaller than x_0. We show that the fluctuation of the total number of splitting events, characterized by the variance, generically undergoes a nontrivial phase transition as one tunes the branching number m through a critical value m=m_c. For m<m_c, the fluctuations are Gaussian where as for m>m_c they are anomalously large and non-Gaussian. We apply this general result to analyze two different search algorithms in computer science.Comment: 5 pages RevTeX, 3 figures (.eps