31 research outputs found

    On the Kinetic Energy Density Functional: The Limit of the Density Derivative Order

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    Within ``orbital-free'' density functional theory, it is essential to develop general kinetic energy density (KED), denoted as t(r)t(\mathbf{r}). This is usually done by empirical corrections and enhancements, gradient expansions, machine learning, or axiomatic approaches to find forms that satisfy physical necessities. In all cases, it is crucial to determine the largest spatial density derivative order, mm in, t(r)t(\mathbf{r}). There have been many efforts to do so, but none have proven general or conclusive and there is no clear guide on how to set mm. In this work, we found that, by imposing KED finitude, m=D+1m=D+1 for systems of dimension DD. This is consistent with observations and provides a needed guide for systematically developing more accurate KEDs

    Analytical and numerical investigation of viscous fluid-filled spherical slip cavity in a spherical micropolar droplet

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    This article presents an analytical and numerical investigation on the quasi-steady, slow flow generated by the movement of a micropolar fluid drop sphere of at a concentrical position within another immiscible viscous fluid inside a spherical slip cavity. Additionally, the effect of a cavity with slip friction along with the change in the micropolarity parameter on the movement of the fluid sphere is introduced. When Reynolds numbers are low, the droplet moves along a diameter that connects their centres. The governing and constitutive differential equations are reduced to a computationally convenient form using appropriate transformations. By using the resulting linear partial differential equations for the stream functions and using the method of separation variables, we can obtain their solutions. General solutions for velocity fields are found using spherical coordinate systems, which are based on the concentric point of the cavity; this allows to obtain solutions to the Navier-Stokes equations internal and external to the spherical droplet. The vorticity-microrotation boundary condition is used in regard to the micropolar droplet case in a viscous fluid. The normalised drag forces acted upon the micropolar drop are illustrated via graphs and tables for diverse values of the viscosity ratio and drop-to-wall radius ratio, with the change of the spin parameter that attaches the microrotation to vorticity. The correction wall factor is shown to increase with an increase in the drop-to-wall radius ratio, when moving from the gas bubble case to the solid sphere case, with an increase in the micropolarity parameter, and with an increase in the slip frictional resistance. This study is relevant due to its potential uses in a variety of biological, natural, and industrial processes, including the creation of raindrops, the investigation of blood flow, fluid-fluid extraction, the forecasting of weather conditions, the rheology of emulsions, and sedimentation phenomena

    The impact of childhood food allergy on quality of life of the paediatric population in Jeddah, Saudi Arabia

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    BackgroundFood allergy is an allergic reaction to any type of food that differs in its severity and impact on the patient's life as well as on caregivers. AimsTo measure the quality of life in the paediatric population with food allergy at National Gourd Health Affairs Jeddah, Saudi Arabia.Methods The food allergy quality of life-parent form was used in this study. The sample size is 75 participants. An Arabic translated and validated version of both questionnaires, with minor modifications were used. Demographic profile, allergy profile, and symptoms profiles were described as frequencies. Cronbach’s alpha was calculated for each food allergy quality of life domain. Food allergy quality of life domains were described using the average scores of the summed corresponding variables. A two-way MANOVA was carried out.Results The total score for patients aged 0–3, 4–6, and 7–12 are 2.01, 2.56, 2.33, respectively. There was no significant interaction between the independent variables (p=0.123). Age group and gender had no effect on the combined score measuring the quality of life (p=0.061, and 0.465, respectively). The total score for parental concern about food safety is 3.56±1.15 (SD) and the total score for child's concern about food safety is 2.81±1.45 (SD). Total score for these domains general health perceptions, parental emotional impact, general mental health, and family and child's activities are 1.6±0.79, 2.84±1.36, 3.09±1.28, 2.39±1.27, respectively.ConclusionThere were no significant differences between age groups or gender in the overall score. Only minimal differences were observed in (emotional, social and dietary limitation). We highly recommend further studies in the same field to be able to generalize the results in the Saudi paediatric population

    Burnout and quality of life among healthcare professionals during the COVID-19 pandemic in Saudi Arabia

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    Background and Objectives. Healthcare professionals (HCPs) have had to deal with large numbers of confirmed or suspected cases of COVID-19 and were at a high risk of burnout and dissatisfaction regarding their work-life integration. This article aims to assess burnout, the work-life balance (WLB), and quality of life (QoL) among healthcare workers and the relationship between these aspects in Saudi Arabia. Methods. An analytical cross-sectional study was conducted among 491 HCPs from five secondary hospitals in Jazan, Saudi Arabia. Three standardized questionnaires were used to gather data, including WLB, burnout, and the WHO Quality of Life-BREF. Results. Healthcare professionals struggled to balance their work and personal lives during COVID-19 and reported many burnout symptoms and a low level of QoL. Two-thirds (68.8%) of HCPs arrived home late from work and (56.6%) skipped a meal. HCPs who worked through a shift without any breaks were found in 57.8%. It was reported that 39.3% of HCPs felt frustrated by technology while being exhausted from their work (60.5%). The correlation coefficients between the WLB and health-related QoL (HRQoL) showed a significant negative correlation for all items, which ranged from (-.099 to -.403, P<0.05). The WLB and burnout scores were successful predictors of low levels of HRQoL (P<0.001 for both explanatory variables). Conclusions. Work-life imbalances, high levels of burnout, and low QoL levels are common among healthcare professionals in Saudi Arabia during COVID-19. Hospital administration should address the WLB and reduce burnout symptoms among HCPs to increase satisfaction and improve the quality of care

    Chlorhexidine versus Povidone-Iodine for the prevention of ‎Surgical Site ‎Infections: A review.‎

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    BackgroundSurgical Site Infections (SSIs) are the third most frequently reported health care-associated ‎infection‎ and it remain a major clinical problem despite improvements in prevention, as they ‎are associated with ‎significant mortality and morbidity. Prevention strategies for SSIs are based ‎on reducing the risk of infection by bacteria, So many antiseptic agents are ‎used, the most ‎common one are Chlorhexidine and Povidone-Iodine.‎AimsTo discuss the ‎findings of RCTs that compare Chlorhexidine versus Povidone-Iodine in the prevention of ‎Surgical ‎Site ‎Infections (SSIs).‎Methods This systematic review was carried out, including PubMed, Google Scholar, and EBSCO that ‎examining randomized trials of Chlorhexidine and Povidone-Iodine to summarize the major ‎RCT that compare Chlorhexidine versus Povidone-Iodine in the prevention of Surgical Site ‎Infections (SSIs).‎Results The review included six randomized studies that compare between Chlorhexidine and Povidone-‎Iodine for the prevention of SSIs. The findings showed that many studies prefer using ‎Chlorhexidine over Povidine-Iodine to reduce SSIs, few studies prefer using PVI as antiseptic ‎and other studies reported that there is no significant difference between both. ConclusionMajority of results prefer using Chlorhexidine than Povidone-Iodine‎ as antiseptics but ‎there were few findings prefer ‎PVI and other studies reported that there was no significant ‎difference between using them as ‎antiseptics.

    Site Assessment and Layout Optimization for Rooftop Solar Energy Generation in Worldview-3 Imagery

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    With the growth of residential rooftop PV adoption in recent decades, the problem of effective layout design has become increasingly important in recent years. Although a number of automated methods have been introduced, these tend to rely on simplifying assumptions and heuristics to improve computational tractability. We demonstrate a fully automated layout design pipeline that attempts to solve a more general formulation with greater geometric flexibility that accounts for shading losses. Our approach generates rooftop areas from satellite imagery and uses MINLP optimization to select panel positions, azimuth angles and tilt angles on an individual basis rather than imposing any predefined layouts. Our results demonstrate that shading plays a critical role in automated rooftop PV optimization and significantly changes the resulting layouts. Additionally, they suggest that, although several common heuristics are often effective, they may not be universally suitable due to complications resulting from geometric restrictions and shading losses. Finally, we evaluate a few specific heuristics from the literature and propose a potential new rule of thumb that may help improve rooftop solar energy potential when shading effects are considered

    To what extent are Arab pilgrims to Makkah aware of the middle east respiratory syndrome coronavirus and the precautions against it?

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    BACKGROUND: Approximately, 80% of the many cases of the Middle East respiratory syndrome coronavirus (MERS-CoV) confirmed worldwide were diagnosed in the Kingdom of Saudi Arabia (KSA). The risk of the disease spreading internationally is especially worrying given the role of KSA as the home of the most important Islamic pilgrimage sites. This means the need to assess Arab pilgrims' awareness of MERS-CoV is of paramount importance. MATERIALS AND METHODS: A cross-sectional study was carried out during Ramadan 2015 in the Holy Mosque in Makkah, Saudi Arabia. Self-administered questionnaires were distributed to 417 Arab participants at King Fahad Extension, King Abdullah Prayer Extension and, King Abdullah Piazza Extension after Taraweeh and Fajr prayers. RESULTS: The mean MERS-CoV knowledge score was 52.56. Majority of the respondents (91.3%) were familiar with MERS-CoV. Saudis had significantly higher knowledge of MERS-CoV than non-Saudis (56.92 ± 18.55 vs. 44.91 ± 25.46, p = 0.001). Females had significantly more knowledge about consanguineous MERS-CoV than males (55.82 ± 19.35 vs. 49.93 ± 23.66, p = 0.006). The average knowledge was significantly higher in respondents who had received health advice on MERS-CoV (56.08 ± 20.86 vs. 50.65 ± 22.51, p = 0.024). With respect to stepwise linear regression, knowledge of MERS-CoV tended to increase by 14.23 (B = 14.23%, p = 0.001) in participants who were familiar with MERS-CoV, and by 8.50 (B = 8.50, p = 0.001) in those who perceived MERS-CoV as a very serious disease. CONCLUSION: There is a great need for educational programs to increase awareness about MERS-CoV

    Epidemiology and Antimicrobial Resistance Patterns of Urinary Tract Infections: A Cross-Sectional Study from Southwestern Saudi Arabia

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    Background: Urinary tract infections (UTIs) are a prevalent form of urinary tract diseases affecting individuals of all ages and genders. In the Kingdom of Saudi Arabia (KSA), UTIs are a significant burden on the healthcare system, comprising 10% of all infections and ranking as the second leading cause of emergency department admissions. Despite this, limited research has been conducted in Saudi Arabia, particularly in Jazan Province, located in the southwestern region. Methods: This retrospective, cross-sectional study encompassed individuals with positive urine cultures who sought care at a tertiary hospital in Jazan between January 2022 and March 2023. A standardized data collection form was utilized to retrieve relevant information from microbiology lab test results and patients’ electronic medical records. Variables such as sex, urine sample collection date, bacterial isolates, antibiotic sensitivity, and resistance were collected using the data collection form. Data were analyzed using SPSS software, version 23.0 (IBM Corp., Armonk, NY, USA). Results: A total of 1082 urinary bacterial samples were isolated and identified. Females accounted for more bacterial infections (62.66%) than males (37.34%). Gram-negative bacteria represented 94% of all isolated strains. The most prevalent pathogens associated with UTIs were Escherichia coli (47.97%), Klebsiella pneumoniae (24.58%), and Pseudomonas aeruginosa (11.55%). Antimicrobial resistance patterns indicated the presence of extended-spectrum beta-lactamase (ESBL) (30.13%), carbapenemase-resistant Enterobacter (CRE) (1.94%), methicillin-resistant Staphylococcus aureus (MRSA) (0.74%), and vancomycin-resistant Enterococci (VRE) (0.18%). UTI incidence demonstrated a higher prevalence in September (13%) compared to other months in 2022. Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa were the predominant Gram-negative multidrug-resistant organisms (MDRO), accounting for 34.42%, 13.95%, and 1.63% of the population. Conclusions: The prevalence of UTIs caused by antibiotic-resistant microbes is notable in Jazan. Consistent with findings from other regions, Escherichia coli remains the most common causative pathogen of UTIs, displaying a seasonal pattern that warrants attention. Approximately 35% of reported cases involve MDRO, with ESBLs accounting for 30%. These results should raise concerns among healthcare officials, highlighting the necessity for further investigations into factors contributing to the circulation of MDRO in Jazan

    Effects of head motion on postural stability in healthy young adults with chronic motion sensitivity

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    Abstract Background Motion sensitivity, or motion sickness, is common in modern vehicular and visually stimulating environments. Several studies have shown a relationship between motion sensitivity and decreased postural stability. We aimed to evaluate the effects of head motion (horizontal and vertical) on postural stability in healthy adults with and without chronic motion sensitivity (CMS). Methods Sixty healthy adult men and women (age, 20–40 years) with CMS (CMS group, n = 30) and without CMS (non-CMS group, n = 30) participated in the study. Postural stability was assessed during three conditions (static, horizontal head motion, and vertical head motion) using computerized dynamic posturography. Group and condition-related differences in equilibrium scores were evaluated. Results There was no significant group x condition interaction (F2,114 = 0.9, partial ƞ2 = 0.04, p = 0.35). However, significant condition-related differences in equilibrium scores were observed (F2,114 = 26.4, partial ƞ2 = 0.31, p < 0.001). Equilibrium scores were significantly worse in the horizontal and vertical head motion conditions compared to those in the static condition (p < 0.001), but were comparable in vertical and horizontal head motion conditions (p = 0.27). Conclusions Postural stability was lower in the horizontal and vertical conditions compared to the static condition. However, horizontal and vertical head motions had comparable effects on postural stability in both CMS and non-CMS groups, contrary to our expectations
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