What Matters Most: Determinants Associated with the Selection of Medical Residencies in Qatar.

Purpose: There have been several studies into medical student career decision making in occidental countries (eg US, UK), but medical career selection in a Middle Eastern context has not been as well studied. This study aims to explore determinants underpinning medical students' residency choice in Qatar. Patients and methods: During the Fall semester of the 2022-2023 academic year, all (n=358) medical students from the College of Medicine at Qatar University were invited to participate in an online explorative questionnaire about students' career choices and the factors determining their selection. Results: Of the 358 students, 184 responded (51%). Respondents had a mean age of 20 years; the majority were female (73.9%), Qatari (54.3%), unmarried (97.3%), and enrolled in a pre-clerkship year (55.0%). The most important career determinant was specialty-specific factors. The relative importance of other determinants differed by gender and stage of training. Among our respondents, male students were more likely to rate role models and influencers as being important to their choice, while female students and Qatari students overall were more likely to cite societal obligation. Medical students in Qatar seemed to have career preferences in mind upon entry into medical education. Later-year students were more likely to identify the importance of work-life balance and place of practice, but were less likely to rank prestige and income as an important determinant. Conclusion: The results of this baseline study suggest that socioeconomic and cultural context influence medical student career decisions.

Time to Move Beyond a Binary Criterion for Gestational Diabetes?

Over the years, several international guidelines have been developed by specialist organizations for the diagnosis of gestational diabetes mellitus (GDM). However, these guidelines vary and lack consensus on what level of glycemia defines GDM and worryingly, there is now evidence of over- or- under-diagnosis of women with GDM by current criteria. Towards this end, the National Priorities Research Program (NPRP) funded a program of research aimed at elucidating the problem with GDM diagnosis. It was determined, on completion of the project, that the solution required diagnosis of graded levels of dysglycemia in pregnancy and not just a diagnosis of presence or absence of GDM. A new diagnostic criterion (called the NPRP criterion) was created based on a single numerical summary of the three readings from the oral glucose tolerance test (GTT) that diagnosed women in pregnancy into four levels: normal, impaired, GDM and high risk GDM. This paper now examines existing GDM criteria vis-à-vis the NPRP criterion. It is noted that no significant change has happened over the years for existing criteria except for a gradual reduction in the threshold values of individual time-points or the number of time points, bringing us towards over-diagnosis of GDM in pregnancy. The new criterion unifies all readings from the GTT into one numerical value and, because it results in four levels of glycemia, represents a new way forwards for GDM diagnosis and can potentially reduce the rates of under diagnosis and over diagnosis of GDM.

Synthesis, X-ray crystallography, computational investigation on quinoxaline derivatives as potent against adenosine receptor A2AAR.

Quinoxaline represents one of the most important classes of heterocyclic compounds, which have exhibited a wide range of biological activities and industrial importance in many different fields. In this regard, we have synthetized two new quinoxaline derivatives. Their structures were confirmed by single-crystal X-ray analysis. The compounds show potent activity against adenosine receptors A2AAR based on structural activity relationship studies. Further molecular docking, molecular dynamics, ADMET analysis, and DFT (density functional theory) calculations were performed to understand the titled compound's future drug candidacy. DFT computations confirmed the good stability of the synthesized compounds, as evidenced by the optimized molecular geometry, HOMO-LUMO energy gap, and intermolecular interactions. NBO analysis confirmed intermolecular interactions mediated by lone pair, bonding, and anti-bonding orbitals. All DFT findings were consistent with experimental results, indicating that the synthesized molecules are highly stable. These findings suggest that the synthesized compounds are promising candidates for further development as drugs for the treatment of A2AAR-related diseases.Communicated by Ramaswamy H. Sarma.

Design, Characterization and SAR Studies of Novel Bioactive Benzylideneacetophenone Derivatives as Insecticidal Agents against Spodoptera frugiperda (Lepidoptera: Noctuidae).

Unintentional environmental effects brought on by insecticides encourage the creation of safer substitutes. A very polyphagous migrating lepidopteran pest species in Africa called S. Frugiperda causes terrible damage. In the current paper, treatment of 4-acetylphenyl 4-methylbenzenesulfonate with different aromatic aldehydes in the presence of NaOH afforded benzylideneacetophenones. The structure of the newly prepared compounds were proved by different spectroscopic techniques such as IR, 1 H-NMR, 13 C NMR, and elemental analysis. We looked at the association between contact with S. frugiperda and stricture reaction to examine their harmful effect. Additionally, S. frugiperda was used for testing the newly created compounds for their ability to kill insects. The majority of substances have been proven to be effective and promising. It has been found that 4-[3-(4-Methylphenyl)prop-2-enoyl]phenyl-4-methyl benzenesulfonate (4) was the most active with an LC50 =3.46 mg/L of 2nd instar larvae and LC50 =9.45 mg/L of 4th instar larvae. Moreover, some of biological and histopathological aspects of the synthesized products were investigated under laboratory conditions.

Automated Identification of Dental Implants: A New, Fast and Accurate Artificial Intelligence System.

INTRODUCTION: Prosthetic complications that occur to some implant prosthetics may require removal of the prosthesis for replacement or repair. Therefore, the presence of a technique to identify the type of dental implant is mandatory to provide the suitable components. Hence, the aim of the current study was to evaluate the accuracy of YOLOv8 object detection algorithm in automatic identification of the type of dental implant from digital periapical radiographs. METHODS: YOLOv8m-seg object detection algorithm was used to build a model to automatically identify the type of dental implant. A set of 2573 digital periapical radiographs for six distinct dental implants manufacturers were used to train the model. The outcomes were evaluated using precision, recall, F1 score and mAP. RESULTS: The overall accuracy of the YOLOv8m-seg model in terms of precision, recall, F1 score and mAP revealed values of 0.919, 0.98, 0.95 and 0.972 respectively. The average detection speed of the images was 1.3 seconds. The model was able to detect and identify multiple implants simultaneously on the same image. CONCLUSIONS: YOLOv8m-seg object detection algorithm is promising in identification of dental implants from periapical radiographs with high detection accuracy (97.2%), fast detection results and multi-implant detection from the same image. CLINICAL SIGNIFICANCE: This AI system can accurately identify the type of osseointegrated dental implants enabling dentists to provide the appropriate prosthetic components even if different implant systems are used within the same patient. This can save tremendous amounts of time, effort and cost for both the dentist and the patient.

Endometrial Carcinoma: A Comprehensive Analysis of Clinical Parameters, Treatment Modalities, and Prognostic Outcomes at a Tertiary Oncology Center in the UAE.

Background Endometrial carcinoma (EC) remains a pressing global health issue, with a discernible upsurge in incidence, especially in developed countries. Notably, the United Arab Emirates (UAE) has witnessed a surge in EC cases, demanding an in-depth, region-specific exploration into the disease's clinical, treatment, and prognostic facets against the backdrop of its unique socio-genetic and environmental contours. Aim This study aimed to profess a comprehensive understanding of EC by examining clinical parameters, treatment modalities, and prognostic outcomes in the UAE context, thereby seeking to delineate potential correlations between varied therapeutic combinations, patient demographics, and tumor characteristics in affecting prognostic outcomes. Materials and methods A retrospective cohort study involving 93 patients diagnosed with EC from January 2011 to March 2023 at a leading oncology center in the UAE was conducted. Data, including demographic information, clinical presentation, treatment modalities, and prognostic outcomes, were meticulously extracted and analyzed. The R software (version 4.2.2) facilitated exhaustive statistical analyses, involving descriptive statistics, correlation analyses with the polycor package, and survival analyses utilizing the Kaplan-Meier method and Cox regression analysis via the survival and survminer packages, respectively. Results Although the correlation matrix revealed a noticeable relationship between "Family history" and "Age," most parameters displayed independence, offering a robust platform for ensuing multivariate analyses. Kaplan-Meier survival curves, stratified by therapeutic modalities, exhibited no statistically significant survival differences across therapeutic cohorts (p-values: 0.44, 0.86, and 0.83). Conversely, the composite Cox regression model underscored "non-national" demographic, Diabetes Mellitus II, and stromal invasion as pivotal prognostic factors, indicating the multifactorial nature of survival in EC patients and emphasizing demographic and tumor characteristics over therapeutic modalities as influential prognostic determinants. Conclusion In conclusion, while therapy types were not directly correlated with survival, demographic and tumor traits prominently impacted prognostic outcomes, advocating for an intricate, multidimensional approach to managing EC in the UAE. This study hopes to sow seeds for subsequent research, shaping clinically and culturally apt practices and policies in the region's healthcare landscape.

Association between pregnancy and severe COVID-19 symptoms in Qatar: A cross-sectional study.

There is inconclusive evidence whether pregnancy exacerbates COVID-19 symptoms or not, and scarce data from the Middle East and North Africa region. The aim of this study was to investigate the association between pregnancy and COVID-19 symptoms in Qatar. This cross-sectional study was carried out using data of all women with confirmed COVID-19, comparing women of child-bearing age (18-49 years). Data of all COVID-19 cases were collected by the Ministry of Public Health (MoPH) in Qatar, between March and September 2020. Symptoms were compared by pregnancy status and classified into moderate and severe. Multivariable logistic and Poisson regression was carried out to investigate the association between pregnancy and severity of COVID-19 symptoms. During the study period, 105 744 individuals were diagnosed with COVID-19, of which 16 908 were women of childbearing age. From that sample, 799 women were pregnant (mean age 29.9 years (SD 5.2)) and 16109 women were not pregnant (mean age 33.1 years (SD 7.8)). After multivariable logistic regression, pregnancy was associated with 1.4-fold higher odds of reporting any symptoms of COVID-19 (OR 1.41, 95% CI 1.18-1.68), and 1.3-fold higher odds of reporting shortness of breath (OR 1.29, 95% CI 1.02-1.63). In a multivariable Poisson regression, pregnancy was also associated with a higher count of symptoms (IRR 1.03, 95%CI 0.98-1.08), although with weak evidence against the null hypothesis. Our findings suggest that, in this setting, pregnant women are more likely to have symptomatic COVID-19, and shortness of breath, compared to women with no pregnancy.

A retrospective comparison of phototherapy need in O-B versus O-A incompatibility in a single Saudi institution.

BACKGROUND: ABO incompatibility is a major risk factor for neonatal indirect hyperbilirubinemia (NIH), requiring treatment. It has been shown that there are racial differences in direct antiglobulin test (DAT) positivity and phototherapy need in the O--B versus (vs) O--A incompatibility. The comparison between the O--B and O--A incompatibility is not well studied in Saudi Arabia. AIMS: We aimed to compare DAT positivity and phototherapy need in O-B vs O-A incompatibility in Saudi Arabia. METHODS: This retrospective cohort study was conducted in one Saudi hospital. We included a convenience sample of neonates born between 01 January 2013 and 31 December 2021. We included healthy neonates admitted to the nursery care unit only, born at≥38 weeks gestation, and had normal G6PD levels. Neonates that had no G6PD level measurement or lost follow-up post-discharge were excluded. The data span was the first 14 days of life. RESULTS: A total of 611 neonates met our inclusion criteria. Positive DAT was more prevalent in the O-B than the O-A incompatibility [43.5% vs 29.2%, p < 0.001). A greater odd of phototherapy need was observed in the O--B vs O-A incompatibility across various strata. Readmission for NIH, use of 360° exposure phototherapy, or intravenous immunoglobulin administration was more prevalent in the O-B than the O-A incompatibility (13.2% vs 5.0%, p < 0.001). A logistic regression analysis revealed that the O-B incompatibility modified the association between DAT positivity and phototherapy need. CONCLUSIONS: The O-B incompatibility had a mediator effect on the relationship between DAT positivity and the need for phototherapy in the study population, which emphasizes that the O-B and O-A are not the same from the NIH point of view.

Metabolic changes after surgical fat removal: A dose-response meta-analysis.

BACKGROUND: Bariatric surgery averts obesity-induced insulin resistance and the metabolic syndrome. By contrast, surgical fat removal is considered merely an esthetic endeavor. The aim of this article was to establish whether surgical fat removal, similar to bariatric surgery, exerts measurable, lasting metabolic benefits. METHODS: PubMed, Embase, and Scopus were searched using the Polyglot Search Translator to find studies examining quantitative expression of metabolic markers. Quality assessment was done using the MethodologicAl STandard for Epidemiological Research scale. The robust-error meta-regression model was employed for this synthesis. RESULTS: Twenty-two studies with 493 participants were included. Insulin sensitivity improved gradually with a maximum reduction in fasting insulin and homeostatic model assessment for insulin resistance of 17 pmol/L and 1 point, respectively, at postoperative day 180. Peak metabolic benefits manifest as a reduction of 2 units in body mass index, 3 kg of fat mass, 5 cm of waist circumference, 15 µg/L of serum leptin, 0.75 pg/ml of tumor necrosis factor-alpha, 0.25 mmol/L of total cholesterol, and 3.5 mmHg of systolic and diastolic blood pressure that were observed at day 50 but were followed by a return to preoperative levels by day 180. Serum high-density lipoproteins peaked at 50 days post-surgery before falling below the baseline. No significant changes were observed in lean body mass, serum adiponectin, resistin, interleukin-6, C-reactive protein, triglyceride, low-density lipoproteins, free fatty acids, and fasting blood glucose. CONCLUSION: Surgical fat removal exerts several metabolic benefits in the short term, but only improvements in insulin sensitivity last beyond 6 months.

Metabolic aspects of surgical subcutaneous fat removal: An umbrella review and implications for future research.

Although obesity is a preventable disease, maintaining a normal body weight can be very challenging and difficult, which has led to a significant increase in the demand for surgical subcutaneous fat removal (SSFR) to improve physical appearance. The need for SSFR is further exacerbated because of the global rise in the number of bariatric surgeries, which is currently the single most durable intervention for mitigating obesity. Fat tissue is now recognized as a vital endocrine organ that produces several bioactive proteins. Thus, SSFR-mediated weight (fat) loss can potentially have significant metabolic effects; however, currently, there is no consensus on this issue. This review focuses on the metabolic sequelae after SSFR interventions for dealing with cosmetic body appearance. Data was extracted from existing systematic reviews and the diversity of possible metabolic changes after SSFR are reported along with gaps in the knowledge and future directions for research and practice. We conclude that there is a potential for metabolic sequelae after SSFR interventions and their clinical implications for the safety of the procedures as well as for our understanding of subcutaneous adipose tissue biology and insulin resistance are discussed.

Novel quinoxaline derivatives as dual EGFR and COX-2 inhibitors: synthesis, molecular docking and biological evaluation as potential anticancer and anti-inflammatory agents.

Novel quinoxaline derivatives (2a-d, 3, 4a, 4b and 5-15) have been synthesized via the reaction of 4-methyl-3-oxo-3,4-dihydroquinoxaline-2-carbohydrazide (1) with different aldehydes, ketones, diketones, ketoesters, as well as hydrazine, phenyl isothiocyanate, carbon disulphide. The synthesized products have been screened for their in vitro anticancer and COX inhibitory activities. Most of the synthesized compounds exhibited good anticancer and COX-2 inhibitory activities. MTT assay revealed that compounds 11 and 13 were the most potent and exhibited very strong anticancer activity against the three cancer cell lines with IC50 values ranging from 0.81 µM to 2.91 µM. Compounds 4a and 5 come next and displayed strong anticancer activity against the three cancer cell lines with IC50 values ranging from 3.21 µM to 4.54 µM. Mechanistically, compounds 4a and 13 were the most active and potently inhibited EGFR with IC50 = 0.3 and 0.4 µM, respectively. Compounds 11 and 5 come next with IC50 = 0.6 and 0.9 µM, respectively. Moreover, compounds 11 and 13 were the most potent as COX-2 inhibitors and displayed higher potency against COX-2 (IC50 = 0.62 and 0.46 µM, respectively) more than COX-1 (IC50 = 37.96 and 30.41 µM, respectively) with selectivity indexes (SI) of 61.23 and 66.11, respectively. Compounds 4a and 5 comes next with IC50 = 1.17 and 0.83 µM and SI of 24.61 and 48.58, respectively. Molecular docking studies into the catalytic binding pocket of both protein receptors, EGFR and COX-2, showed good correlation with the obtained biological results. Parameters of Lipinski's rule of five and Veber's standard were calculated and revealed that compounds 4a, 5, 11 and 13 had a reasonable drug-likeness with acceptable physicochemical properties. Therefore, based on the obtained biological results accompanied with the docking study and physicochemical parameters, it could be concluded that compounds 4a, 5, 11 and 13 could be used as promising orally absorbed dual anti-inflammatory agents via inhibition of COX-2 enzyme and anticancer candidates via inhibition of EGFR enzyme and could be used as a future template for further investigations.

Characteristics of Elderly Hip Fracture Patients in Jordan: A Multicenter Epidemiological Study.

Background: Elderly hip fractures represent a global health care burden. Several reports expected a massive increase in the incidence of hip fractures by the next few decades. Knowing the epidemiology of hip fractures is crucial for planning health care policies. The purpose of this study is to provide a nationwide epidemiological overview of hip fractures in Jordan and to report the perioperative outcomes that may help to improve the delivered healthcare. . Methods: We conducted a retrospective study at 2 university hospitals and 2 major governmental hospitals in Jordan. We reviewed the records for all patients (age >55 years) who were diagnosed with hip fractures over a 3 years duration (2019-2021). We documented the patient's characteristics and the perioperative data (including preoperative, intraoperative, and postoperative details including the 1-year mortality). . Results: The total number of included patients was 1268; more than half (53.7%) were females. The mean age is 75 years (SD 9.7). The most common fracture type was trochanteric (66.2%) . 7% of patients had a prior contralateral hip fracture . The average time from admission to surgery was 2.96 days (SD 2.63). The surgery was done within 48 hours for 56.7% of patients. Approximately, one-third of all patients (34.5%) received a blood transfusion. The average length of hospital stay is 7.44 days (SD 5). The overall rate of postoperative thromboembolic events, readmission within 1 month, and revision for the same surgery are 2.4% , 10.7% , and 3% respectively. The 1-month, 6-month, and 12-month mortality rates are 4.5%, 9.1%, and 12.8% respectively. Conclusion: The annual incidence of elderly hip fractures in Jordan is approximately 96 per 100,000 individuals. The 1-year mortality rate of hip fractures in Jordan is 12.8% . Both findings are in the lower range of nearby Arab countries.

Association between pregnancy and severe COVID-19 symptoms in Qatar: a cross-sectional study

BackgroundThere is inconclusive evidence whether pregnancy exacerbates COVID-19 symptoms or not, and scarce data from the Middle East and North Africa region. The aim of this study was to investigate the association between pregnancy and COVID-19 symptoms in Qatar. MethodsThis cross-sectional study was carried out using data of all women with confirmed COVID-19, comparing pregnant and non-pregnant women of child-bearing age (18-49 years). Data of all COVID-19 cases were collected by the Ministry of Public Health (MoPH) in Qatar, between March and September 2020. Symptoms were compared by pregnancy status and classified into moderate and severe. Multivariable logistic and poisson regression was carried out to investigate the association between pregnancy and severity of COVID-19 symptoms. ResultsDuring the study period, 105744 individuals were diagnosed with COVID-19, 16908 were women of childbearing age. From that sample, 799 women who were pregnant (mean age 29.9 years (SD 5.2)) and 16109 women who were not pregnant (mean age 33.1 years (SD 7.8)). After multivariable logistic regression, pregnancy was associated with a 1.4-fold higher odds of reporting any symptoms of COVID-19 (OR 1.41, 95% CI 1.18-1.68), and 1.3-fold higher odds of reporting shortness of breath (OR 1.29, 95% CI 1.02-1.63). After multivariable poisson regression, pregnancy was also associated with a higher number of symptoms (IRR 1.03, 95%CI 0.98-1.08). ConclusionOur findings suggest that, in this setting, pregnant women are more likely to have symptomatic COVID-19, and shortness of breath, compared to non-pregnant women of childbearing age.

Quantum optimization of maximum independent set using Rydberg atom arrays.

Realizing quantum speedup for practically relevant, computationally hard problems is a central challenge in quantum information science. Using Rydberg atom arrays with up to 289 qubits in two spatial dimensions, we experimentally investigate quantum algorithms for solving the maximum independent set problem. We use a hardware-efficient encoding associated with Rydberg blockade, realize closed-loop optimization to test several variational algorithms, and subsequently apply them to systematically explore a class of graphs with programmable connectivity. We find that the problem hardness is controlled by the solution degeneracy and number of local minima, and we experimentally benchmark the quantum algorithm's performance against classical simulated annealing. On the hardest graphs, we observe a superlinear quantum speedup in finding exact solutions in the deep circuit regime and analyze its origins.

Impact of Smoking on COVID-19 Symptoms in Non-Vaccinated Patients: A Matched Observational Study from Qatar.

Purpose: Predisposition to acute illness from COVID-19 is suggested to correlate with cigarette smoking as it augments the risk of developing cardiovascular and respiratory illnesses, including infections. However, the effects of smoking on COVID-19 symptoms are not well described and controversial. In this study, we aim to explore the associations between smoking and COVID-19 symptoms. Subjects and Methods: A cross-sectional study using the Ministry of Public Health (MoPH), Qatar database was administered to a Qatari population with confirmed COVID-19 disease who filled in pre-defined phone-call questionnaire between 27th February 2020 and 31st December 2020. We analyzed 11,701 non-vaccinated COVID-19 individuals (2952 smokers and 8749 non-smokers) with confirmed RT-PCR test results. The association of smoking and the presence of symptoms as well as patient characteristics was calculated using Pearson's Chi-square and Fisher's exact tests, adjusting for potential covariates. Results: Compared with the non-smokers, symptomatic COVID-19 infection is significantly higher in smokers. In addition, we found fever as the most common symptom developed in COVID-19 patients followed by cough, headache, muscle ache, and sore throat. As compared to other symptoms, association of smoking with chills and abdominal pain was less evident (P < 0.05 and P < 0.001, respectively). However, both groups showed similar rates of developing cough. Conclusion: In conclusion, smoking is associated with COVID-19 symptoms frequency in non-vaccinated patients; nevertheless, further investigations are necessary to understand the mechanism of this association which could generate new targets for the management of COVID-19 in smoker patients.

The prevalence of adaptive immunity to COVID-19 and reinfection after recovery - a comprehensive systematic review and meta-analysis.

This study aims to estimate the prevalence and longevity of detectable SARS-CoV-2 antibodies and T and B memory cells after recovery. In addition, the prevalence of COVID-19 reinfection and the preventive efficacy of previous infection with SARS-CoV-2 were investigated. A synthesis of existing research was conducted. The Cochrane Library, the China Academic Journals Full Text Database, PubMed, and Scopus, and preprint servers were searched for studies conducted between 1 January 2020 to 1 April 2021. Included studies were assessed for methodological quality and pooled estimates of relevant outcomes were obtained in a meta-analysis using a bias adjusted synthesis method. Proportions were synthesized with the Freeman-Tukey double arcsine transformation and binary outcomes using the odds ratio (OR). Heterogeneity was assessed using the I2 and Cochran's Q statistics and publication bias was assessed using Doi plots. Fifty-four studies from 18 countries, with around 12,000,000 individuals, followed up to 8 months after recovery, were included. At 6-8 months after recovery, the prevalence of SARS-CoV-2 specific immunological memory remained high; IgG - 90.4% (95%CI 72.2-99.9, I2 = 89.0%), CD4+ - 91.7% (95%CI 78.2-97.1y), and memory B cells 80.6% (95%CI 65.0-90.2) and the pooled prevalence of reinfection was 0.2% (95%CI 0.0-0.7, I2 = 98.8). Individuals previously infected with SARS-CoV-2 had an 81% reduction in odds of a reinfection (OR 0.19, 95% CI 0.1-0.3, I2 = 90.5%). Around 90% of recovered individuals had evidence of immunological memory to SARS-CoV-2, at 6-8 months after recovery and had a low risk of reinfection.RegistrationPROSPERO: CRD42020201234.

The Odds Ratio is "portable" across baseline risk but not the Relative Risk: Time to do away with the log link in binomial regression.

OBJECTIVES: In a recent paper we suggest that the relative risk (RR) be replaced with the odds ratio (OR) as the effect measure of choice in clinical epidemiology. In response, Chu, and colleagues raise several points that argue for the status quo. In this paper, we respond to their response. STUDY DESIGNS AND SETTINGS: We use the same examples given by Chu and colleagues to recompute estimates of effect and demonstrate the problem with the RR. RESULTS: We reaffirm the following findings: a) the OR and RR measure different things and their numerical difference is only important if misinterpreted b) this potential misinterpretation is a trivial issue compared to the lack of portability of the RR c) the same examples reaffirm non-portability of the RR and demonstrate how misleading the results might be in contrast to the OR, which is independent of the baseline risk d) the concept of non-collapsibility for the OR should be expected in the presence of a non-confounding risk factor, and is not a bias e) the log link in regression models that generate RRs as well as the use of RRs in meta-analysis is shown to be problematic using the same examples. CONCLUSION: The OR should replace the RR in clinical research and meta-analyses though there should be conversion of the end product into ratios or differences of risk, solely, for interpretation. To this end we provide a Stata module (logittorisk) for this purpose.

Probing topological spin liquids on a programmable quantum simulator.

Quantum spin liquids, exotic phases of matter with topological order, have been a major focus in physics for the past several decades. Such phases feature long-range quantum entanglement that can potentially be exploited to realize robust quantum computation. We used a 219-atom programmable quantum simulator to probe quantum spin liquid states. In our approach, arrays of atoms were placed on the links of a kagome lattice, and evolution under Rydberg blockade created frustrated quantum states with no local order. The onset of a quantum spin liquid phase of the paradigmatic toric code type was detected by using topological string operators that provide direct signatures of topological order and quantum correlations. Our observations enable the controlled experimental exploration of topological matter and protected quantum information processing.

Prevalence and determinants of symptomatic COVID-19 infection among children and adolescents in Qatar: a cross-sectional analysis of 11 445 individuals.

There is a paucity of evidence about the prevalence and risk factors for symptomatic infection among children. This study aimed to describe the prevalence of symptomatic coronavirus disease 2019 (COVID-19) and its risk factors in children and adolescents aged 0-18 years in Qatar. We conducted a cross-sectional study of all children aged 0-18 years diagnosed with COVID-19 using polymerase chain reaction in Qatar during the period 1st March to 31st July 2020. A generalised linear model with a binomial family and identity link was used to assess the association between selected factors and the prevalence of symptomatic infection. A total of 11 445 children with a median age of 8 years (interquartile range (IQR) 3-13 years) were included in this study. The prevalence of symptomatic COVID-19 was 36.6% (95% confidence interval (CI) 35.7-37.5), and it was similar between children aged <5 years (37.8%), 5-9 years (34.3%) and 10 + years (37.3%). The most frequently reported symptoms among the symptomatic group were fever (73.5%), cough (34.8%), headache (23.2%) and sore throat (23.2%). Fever (82.8%) was more common in symptomatic children aged <5 years, while cough (38.7%) was more prevalent in those aged 10 years or older, compared to other age groups. Variables associated with an increased risk of symptomatic infection were; contact with confirmed cases (RD 0.21; 95% CI 0.20-0.23; P = 0.001), having visited a health care facility (RD 0.54; 95% CI 0.45-0.62; P = 0.001), and children aged under 5 years (RD 0.05; 95% CI 0.02-0.07; P = 0.001) or aged 10 years or older (RD 0.04; 95% CI 0.02-0.06; P = 0.001). A third of the children with COVID-19 were symptomatic with a higher proportion of fever in very young children and a higher proportion of cough in those between 10 and 18 years of age.