166 research outputs found

    Early Prediction of Employee Turnover Using Machine Learning Algorithms

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    Employee turnover is a serious challenge for organizations and companies. Thus, the prediction of employee turnover is a vital issue in all organizations and companies. The present work proposes prediction models for predicting the turnover intentions of workers during the recruitment process. The proposed models are based on k-nearest neighbors (KNN) and random forests (RF) machine learning algorithms. The models use the dataset of employee turnover created by IBM. The used dataset includes the most essential features, which are considered during the recruitment process of the employee and may lead to turnover. These features are salary, age, distance from home, marital status, and gender. The KNN-based model exhibited better performance in terms of accuracy, precision, F-score, specificity (SP), and false-positive rate (FPR) in comparison to the RF-based model. The models predict the average probability percentage of turnover intentions of the workers. Therefore, the models can be used to aid the human resource managers to make precautionary decisions; whether the candidate employee is likely to stay or leave the job, depending on the given relevant information about the candidate employee

    A robust uniform B-spline collocation method for solving the generalized PHI-four equation

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    In this paper, we develop a numerical solution based on cubic B-spline collocation method. By applying Von-Neumann stability analysis, the proposed technique is shown to be unconditionally stable. The accuracy of the presented method is demonstrated by a test problem. The numerical results are found to be in good agreement with the exact solution

    Low-Loss Super-Wide Band Antenna over Customized Substrate

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    In this work, a super wide band antenna is proposed to operate in the frequency band 2.3-23 GHz. The antenna has two planar arms with a modified diamond shape printed on the opposite faces of three-layer dielectric substrate. Each arm of the antenna is capacitively coupled to circular sector near its end to increase the impedance matching bandwidth. The dielectric substrate is customized to fit the shape of the antenna arms and the parasitic elements to reduce the dielectric loss. The substrate material is composed of three layers. The upper and lower layers are Rogers RO3003TM of 0.13 mm thickness and the middle layer is made of paper of 2.3 dielectric constant and 2.7 mm thickness. The antenna is fed through a wide band impedance matching balun. The antenna design stages are performed through electromagnetic simulations concerned with the parametric study to get the optimum antenna dimensions to numerically investigate the role of the parasitic element to enhance the antenna performance. A prototype of the proposed antenna is fabricated to validate the simulation results. The experimental measurements come in good agreement with the simulation results and both of them show that the antenna operates efficiently over the frequency band 2.3-23 GHz with minimum radiation efficiency of 97% and maximum gain of 5.2 dBi. The antenna has bandwidth to dimension ratio (BDR) of 1360

    Polycyclic Aromatic Hydrocarbons in Grilled Meats from Restaurants

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    Polycyclic aromatic hydrocarbons are a group of lipophilic compounds that can be generated during the preparation of food items at elevated temperatures. They are regarded as potentially genotoxic and carcinogenic to human beings, related to increased incidence of breast and colorectal cancers, oxidative DNA injury, and bad effects on children neuro-differentiation. Thus, they are considered a public health concerns. A total of thirty samples of grilled beef steak, beef kofta and chicken (ten each) were collected from different restaurants. The samples were extracted by magnesium sulfate and sodium acetate in acetonitrile then purified in magnesium sulfate, primary, secondary amine and silica gel, and finally measured by gas chromatography-mass spectrometry (GC-MS). Benzo[a]pyrene was recorded with the highest average level (3.63µg/kg) in grilled kofta samples, but it was not detected in chicken samples. On the other hand, PAH4, PAH8 and ƩPAHs content were more abundant in grilled beef steak (5.32, 9.97 and 56.91µg/kg). Meanwhile, they recorded the least concentrations of grilled chicken from different restaurants. Furthermore, benzo[a]pyrene exceeded the permissible limits of the European Commission and Egyptian National Food Safety Authority in grilled kofta samples; further studies are needed to investigate the limits of exposure to these harmful compounds from meats and other food items

    Core Microbial Functional Activities in Ocean Environments Revealed by Global Metagenomic Profiling Analyses

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    Metagenomics-based functional profiling analysis is an effective means of gaining deeper insight into the composition of marine microbial populations and developing a better understanding of the interplay between the functional genome content of microbial communities and abiotic factors. Here we present a comprehensive analysis of 24 datasets covering surface and depth-related environments at 11 sites around the world's oceans. The complete datasets comprises approximately 12 million sequences, totaling 5,358 Mb. Based on profiling patterns of Clusters of Orthologous Groups (COGs) of proteins, a core set of reference photic and aphotic depth-related COGs, and a collection of COGs that are associated with extreme oxygen limitation were defined. Their inferred functions were utilized as indicators to characterize the distribution of light- and oxygen-related biological activities in marine environments. The results reveal that, while light level in the water column is a major determinant of phenotypic adaptation in marine microorganisms, oxygen concentration in the aphotic zone has a significant impact only in extremely hypoxic waters. Phylogenetic profiling of the reference photic/aphotic gene sets revealed a greater variety of source organisms in the aphotic zone, although the majority of individual photic and aphotic depth-related COGs are assigned to the same taxa across the different sites. This increase in phylogenetic and functional diversity of the core aphotic related COGs most probably reflects selection for the utilization of a broad range of alternate energy sources in the absence of light.This work was supported by King Abdullah University for Science and Technology Global Collaborative Partners (GCR) program. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

    Ficolin-2 Levels and FCN2 Haplotypes Influence Hepatitis B Infection Outcome in Vietnamese Patients

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    Human Ficolin-2 (L-ficolins) encoded by FCN2 gene is a soluble serum protein that plays an important role in innate immunity and is mainly expressed in the liver. Ficolin-2 serum levels and FCN2 single nucleotide polymorphisms were associated to several infectious diseases. We initially screened the complete FCN2 gene in 48 healthy individuals of Vietnamese ethnicity. We genotyped a Vietnamese cohort comprising of 423 clinically classified hepatitis B virus patients and 303 controls for functional single nucleotide polymorphisms in the promoter region (-986G>A, -602G>A, -4A>G) and in exon 8 (+6424G>T) by real-time PCR and investigated the contribution of FCN2 genotypes and haplotypes to serum Ficolin-2 levels, viral load and liver enzyme levels. Haplotypes differed significantly between patients and controls (P = 0.002) and the haplotype AGGG was found frequently in controls in comparison to patients with hepatitis B virus and hepatocellular carcinoma (P = 0.0002 and P<0.0001) conferring a protective effect. Ficolin-2 levels differed significantly between patients and controls (p<0.0001). Patients with acute hepatitis B had higher serum Ficolin-2 levels compared to other patient groups and controls.The viral load was observed to be significantly distributed among the haplotypes (P = 0.04) and the AAAG haplotype contributed to higher Ficolin-2 levels and to viral load. Four novel single nucleotide polymorphisms in introns (-941G>T, -310G>A, +2363G>A, +4882G>A) and one synonymous mutation in exon 8 (+6485G>T) was observed. Strong linkage was found between the variant -986G>A and -4A>G. The very first study on Vietnamese cohort associates both Ficolin-2 serum levels and FCN2 haplotypes to hepatitis B virus infection and subsequent disease progression

    Laser excitation of the 1s-hyperfine transition in muonic hydrogen

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    The CREMA collaboration is pursuing a measurement of the ground-state hyperfine splitting (HFS) in muonic hydrogen (μ\mup) with 1 ppm accuracy by means of pulsed laser spectroscopy to determine the two-photon-exchange contribution with 2×1042\times10^{-4} relative accuracy. In the proposed experiment, the μ\mup atom undergoes a laser excitation from the singlet hyperfine state to the triplet hyperfine state, {then} is quenched back to the singlet state by an inelastic collision with a H2_2 molecule. The resulting increase of kinetic energy after the collisional deexcitation is used as a signature of a successful laser transition between hyperfine states. In this paper, we calculate the combined probability that a μ\mup atom initially in the singlet hyperfine state undergoes a laser excitation to the triplet state followed by a collisional-induced deexcitation back to the singlet state. This combined probability has been computed using the optical Bloch equations including the inelastic and elastic collisions. Omitting the decoherence effects caused by {the laser bandwidth and }collisions would overestimate the transition probability by more than a factor of two in the experimental conditions. Moreover, we also account for Doppler effects and provide the matrix element, the saturation fluence, the elastic and inelastic collision rates for the singlet and triplet states, and the resonance linewidth. This calculation thus quantifies one of the key unknowns of the HFS experiment, leading to a precise definition of the requirements for the laser system and to an optimization of the hydrogen gas target where μ\mup is formed and the laser spectroscopy will occur.Comment: 21 pages, 4 figure

    International Lower Limb Collaborative (INTELLECT) study: a multicentre, international retrospective audit of lower extremity open fractures

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    International lower limb collaborative (INTELLECT) study: a multicentre, international retrospective audit of lower extremity open fractures

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    Trauma remains a major cause of mortality and disability across the world1, with a higher burden in developing nations2. Open lower extremity injuries are devastating events from a physical3, mental health4, and socioeconomic5 standpoint. The potential sequelae, including risk of chronic infection and amputation, can lead to delayed recovery and major disability6. This international study aimed to describe global disparities, timely intervention, guideline-directed care, and economic aspects of open lower limb injuries
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