Set Of Cross Sections Research Articles

Delayed bedtime on non-school days associates with higher weight and waist circumference in children: Cross-sectional and longitudinal analyses with Mendelian randomisation.

Sleep duration has been linked with obesity in population-based studies. Less is known about bedtimes and, especially, if discrepancy between bedtimes on school and non-school days associate with adiposity in children. The associations of self-reported bedtimes with the body mass index z-score (BMIz) and waist-to-height ratio (WtHr) were examined among children with a mean (SD) age of 11.2 (0.85) years in cross-sectional (n=10,245) and longitudinal (n=5085) study settings. The causal relationship of whether BMIz contributes to bedtimes, was further examined in a subset of 1064 participants by exploiting Mendelian randomisation (MR). After adjusting for sleep duration and other confounders, every 0.5 h later bedtime on non-school nights and a delay in bedtime in non-school nights compared with school nights associated with 0.048 (95% CI 0.027; 0.069) and 0.08 (95% CI 0.056; 0.105) higher BMIz as well as 0.001 (95% CI 0; 0.002) and 0.004 (95% CI 0.003; 0.005) with higher WtHr, respectively. Moreover, every 0.5-h delay in bedtime in non-school nights compared with school nights associated with 0.001 (95% CI 0; 0.002) greater increase in WtHr in the 2.5 years follow-up. Thus, a 2-h delay in bedtime at the age of 11 years corresponds with a 0.6 cm increase in waist circumference. The MR analysis did not indicate an opposite causal relationship: higher BMIz was not causing delayed bedtimes. Later bedtime on non-school days and discrepancy in bedtimes associated with increased BMIz and WtHr, while longitudinally these predicted higher WtHr, independently of sleep duration. Promoting early bedtimes, especially on weekends, should be considered in obesity prevention among school-aged children.

A conservative method for estimating the uncertainty for the probability of an upper-level event in a fault tree

Abstract. Aim. The aim of the paper is to construct a non-simulation method for finding the confidence interval for the probability of an upper-level event of a failure tree. Iterative Monte Carlo algorithms require very much time and computational resources, especially for large fault trees. Therefore, developing “fast” algorithms for finding uncertainty in a calculated fault tree is extremely important.Methods. The algorithm was developed using classical methods of the probability theory, mathematical statistics and dependability theory. The mathematical foundation of the algorithm is the central limit theorem and certain properties of the dispersion of a random variable from the probability theory. To simplify calculations, the confidence interval was built on the assumption of a lognormal distribution of the failure rate estimate with a certain specified error factor. The initial information consists of a set of minimal cross-sections defined for the fault tree using specialized software tools, as well as dependability parameters of the events in each of the cross-sections. The cross-sections may contain dependent events that are part of common cause failure (ССF) groups. Various ССF accounting models, including the betafactor model, alpha-factor model, etc., can be used to calculate the probability of such events. To simplify the set of cross-sections, a program code is used that groups the cross-sections that are identical in value and meaning. Results. A conservative method for constructing a confidence interval for the probability of an upper-level event in a fault tree was developed. The method is not iterative and allows identifying the uncertainty of the final result for randomly-sized fault trees.Conclusions. The algorithm for identifying the uncertainty can be used instead of the Monte Carlo method in specialized software suites that calculate fault trees.

Role of the ρ(1450) in low-energy observables from an analysis in the meson dominance approach

The $\ensuremath{\rho}(1450)$ vector meson (${\ensuremath{\rho}}^{\ensuremath{'}}$) is becoming increasingly important to properly describe precision observables. We analyze a set of decay modes and cross sections, in the low-energy regime, to determine the role played by this meson. This is done through the extraction of the parameters for its description, in the context of the vector meson dominance model and its effective hadronic interactions, involving the low mass lying hadrons ($\ensuremath{\rho}$, $\ensuremath{\omega}$, and $\ensuremath{\pi}$). In a first step, we determine the parameters of the model from ten decay modes which are insensitive to the ${\ensuremath{\rho}}^{\ensuremath{'}}$. Then, we consider the $\ensuremath{\omega}\ensuremath{\rightarrow}3\ensuremath{\pi}$ decay and exhibit the need to extend the description, by incorporating the ${\ensuremath{\rho}}^{\ensuremath{'}}$ and a contact term as prescribed by the Wess-Zumino-Witten anomaly. In a second step, we incorporate the data from the ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}3\ensuremath{\pi}$ cross section (as measured by SND, CMD2, BABAR, and BESIII) and then the ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}{\ensuremath{\pi}}^{0}\ensuremath{\gamma}$ data (as measured by SND and CDM2) to further restrict the ${\ensuremath{\rho}}^{\ensuremath{'}}$ parameters validity region. As an application of the results, we compute the ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}4\ensuremath{\pi}$ cross section for the so-called omega channel, measured by BABAR, and find a good description of the data considering the parameters found. As a byproduct, the coupling between $\ensuremath{\rho}$, $\ensuremath{\omega}$, and $\ensuremath{\pi}$ (${g}_{\ensuremath{\rho}\ensuremath{\omega}\ensuremath{\pi}}=11.314\ifmmode\pm\else\textpm\fi{}0.383\text{ }\text{ }{\mathrm{GeV}}^{\ensuremath{-}1}$) is found to be consistent with all the relevant observables, upon the inclusion of the ${\ensuremath{\rho}}^{\ensuremath{'}}$ and the contact term.

Associating Health-Related Quality-of-Life Score with Time Uses to Inform Productivity Measures in Cost-Effectiveness Analysis.

The Second Panel on Cost Effectiveness in Health and Medicine recommended that cost-effectiveness analyses (CEA) explicitly incorporate the valuation of productive time from a societal perspective. We developed a new approach to capture productivity impacts in CEA without direct evidence on these impacts by associating varying levels of health-related quality-of-life (HrQoL) score with different time uses in the United States. We conceptualized a framework that estimates the association between HrQoL score with productivity through time uses. We used the American Time-Use Survey (ATUS) from year 2012-2013, when data on a Well-Being Module (WBM) was additionally collected alongside ATUS. The WBM measured the quality of life (QoL) score using a visual analog scale. To operationalize our conceptual framework, we employed an econometric approach that addressed three technical issues in the observed data: (i) distinction between overall QoL and HrQoL, (ii) correlation across different categories of time use and the share structure of time-use data, and (iii) reverse causality between time uses and HrQoL score in a cross-sectional setting. Furthermore, we developed a metamodel-based algorithm to summarize the numerous estimates from the primary econometric model efficiently. Finally, we illustrated the use of our algorithm to calculate productivity and time spent seeking care costs in an empirical CEA of aprostate cancer treatment. We provide the estimates of the metamodel algorithm. Incorporating these estimates into the empirical CEA reduced the incremental cost-effectiveness ratio by 27%. Our estimates can facilitate the inclusion of productivity and time spent seeking care in CEA as recommended by the Second Panel.

Determination and assessment of a complete and self-consistent electron-neutral collision cross-section set for the C4F7N molecule

The perfluoronitrile C4F7N is considered a promising SF6-alternative in high-voltage gas-insulated apparatus, thanks to its high dielectric strength and low global warming potential. However, a complete and consistent set of electron-neutral collision cross-sections of C4F7N is still lacking, which hinders relevant plasma modeling. In this contribution, the available electron-neutral collision cross-sections of C4F7N are first compiled and assessed. The initial cross-sections are adjusted iteratively by the electron swarm method to determine a complete and self-consistent cross-section set of C4F7N for the first time. The set is validated by a systematic comparison of electron swarm parameters between Boltzmann equation analysis and experimental measurements in pure C4F7N as well as C4F7N/N2 and C4F7N/Ar mixtures. The proposed cross-section set of C4F7N will be made available to the community in the LXCat database. It will be of particular importance for applications with an emphasis on the discharge mechanisms of this novel gas.

Establishment of DeCART/MIG stochastic sampling code system and Application to UAM and BEAVRS benchmarks

In this study, a DeCART/MIG uncertainty quantification (UQ) analysis code system with a multi-correlated cross section stochastic sampling (S.S.) module was established and verified through the UAM (Uncertainty Analysis in Modeling) and the BEAVRS (Benchmark for Evaluation And Validation of Reactor Simulations) benchmark calculations. For the S.S. calculations, a sample of 500 DeCART multi-group cross section sets for two major actinides, i.e., 235U and 238U, were generated by the MIG code and covariance data from the ENDF/B-VII.1 evaluated nuclear data library. In the three pin problems (i.e. TMI-1, PB2, and Koz-6) from the UAM benchmark, the uncertainties in kinf by the DeCART/MIG S.S. calculations agreed very well with the sensitivity and uncertainty (S/U) perturbation results by DeCART/MUSAD and the S/U direct subtraction (S/U-DS) results by the DeCART/MIG. From these results, it was concluded that the multi-group cross section sampling module of the MIG code works correctly and accurately. In the BEAVRS whole benchmark problems, the uncertainties in the control rod bank worth, isothermal temperature coefficient, power distribution, and critical boron concentration due to cross section uncertainties were calculated by the DeCART/MIG code system. Overall, the uncertainties in these design parameters were less than the general design review criteria of a typical pressurized water reactor start-up case. This newly-developed DeCART/MIG UQ analysis code system by the S.S. method can be widely utilized as uncertainty analysis and margin estimation tools for developing and designing new advanced nuclear reactors.

Making the Myths of Dating Violence Visible: Developing a New Scale and Testing Its Psychometrics Through Cross-Sectional and Longitudinal Evidence.

Myths refer to misperceptions, overgeneralizations, or ideas that most people believe in but do not necessarily reflect the truth. To date, research on the myths surrounding dating violence (DV) has not received much attention, most probably due to the lack of a validated measure. Thus, we developed a standardized measure to gauge DV myths and test its psychometrics. The instrument's design is based on three studies utilizing cross-sectional and longitudinal sets of data. In Study 1, in a sample of 259 emerging adults, predominantly college students, the explanatory factor analysis revealed a solid three-factor structure. In Study 2, in a separate sample of 330 emerging adults, primarily college students, we cross-validated the factor structure via confirmatory factor analysis. We also provided evidence for concurrent validity. In Study 3, we revealed that our newly developed scale had predictive validity among dating and non-dating emerging adults, mostly college students, via longitudinal data. Based on the findings from three studies, we can buoyantly announce that the Dating Violence Myths scale is a promising novel and standardized tool for measuring beliefs about DV. The cross-sectional and longitudinal evidence alludes to a need for DV myths to be debunked to reduce psychological DV attitudes, perceptions, and behaviors among emerging adults.

An Efficient High-to-Low Iterative Method for Light Water Reactor Analysis Based on NEAMS Tools

The so-called two-step method involving the consecutive lattice physics and core simulation has been successfully and widely used in large-scale nuclear reactor calculations thanks to its superior computational efficiency and a satisfactory level of accuracy. However, its performance is challenged by the ever-increasing level of heterogeneity in core designs due to the use of infinite lattice approximation in the lattice calculation and its inability to update cross-section sets according to the core environment change. This paper introduces an alternative approach for light water reactor steady-state core analysis. During the core calculation process, iterations between the local lattice transport calculation and the global core nodal calculation are conducted. These iterations continuously update the boundary condition applied to the lattice model and generate updated cross-section sets. This is done through the iteration between the local lattice transport calculation and the global core nodal simulation. The neutronics high-to-low (Hi2Lo) scheme was formulated using Nuclear Energy Advanced Modeling and Simulation or NEAMS codes, in particular, with the modified PROTEUS-MOC and PROTEUS-NODAL serving as the transport lattice solver and full-core nodal solver, respectively. The verification of the implemented Hi2Lo iterative scheme on the two-dimensional C5G7-TD benchmark problem shows that the Hi2Lo scheme outperforms the two-step approach in terms of prediction accuracy for the key responses of interest (e.g., the system eigenvalue and power distribution) at a computational cost lower than that of the direct full-core transport calculation. To further improve its efficiency, an acceleration method has been developed and implemented for the Hi2Lo approach, and the results indicate that the acceleration method can significantly reduce the run time of a full-core transport solution by a factor of 14 while generating solutions with comparable accuracy.

Measurements of perfluoro-n-heptane and perfluoro-n-octane absorption cross-sections from 300 to 350 K

Perfluoroalkanes are fully fluorinated greenhouse gases. These compounds are chemically inert due to their C–F bonds and therefore have atmospheric lifetimes of thousands of years. Although regulated under the Kyoto Protocol, atmospheric concentrations of perfluoroalkanes have continued to increase since 1997. To quantify the climate impact of perfluoro-n-heptane and perfluoro-n-octane, spectral data are required to calculate climate metrics such as the radiative efficiency and global warming potential. Experimental measurements are scarce for these compounds and are only available at 296 and 297 K. In this work, a set of absorption cross-sections is provided in the range 515–1500 cm−1 at 0.1 cm−1 resolution for nine temperatures between 300 and 350 K. There is general agreement between literature values and the absorption cross-sections and climate metrics measured in this work. These quantities do not show significant temperature dependence. The temperature averaged radiative efficiency is 0.50 ± 0.06 and 0.54 ± 0.07 Wm−2ppbv−1 for n–C7F16 and n–C8F18, respectively. The temperature averaged 100-year global warming potential is 8738 ± 1149 for n–C7F16 and 8392 ± 1103 for n–C8F18.

Comparison of oxidative stress levels during the third Trimester in normal pregnancy and preeclampsia.

The placenta is a complex transiently formed organ which plays a crucial role in the development of the foetus. As the placenta is responsible for maintaining pregnancy placental defects are mainly responsible for pregnancy-related issues. Preeclampsia is a pregnancy-related disorder due to uteroplacental insufficiency resulting from deficient remodelling of spiral arteries causing ischemic reperfusion injury which is finally responsible for the generation of reactive oxygen species and oxidative stress by the placenta. So, this study was planned to determine and compare serum levels of oxidative stress markers (ischemia-modified albumin and malondialdehyde) in preeclampsia and normal pregnancy in the third trimester. Study design: Cross-sectional comparative study Settings Gynae/Obs Department and Pathology Laboratory, Lahore General Hospital, Lahore. Study population: 42 Pregnant females at 34-36 weeks of gestation were selected. Group 1 compromised 21 normal healthy pregnant females and group 2 included 21 preeclamptic patients. Sampling technique: non-probability purposive sampling. Blood samples were taken at 34-36 weeks of gestation. Serum was stored for ischemiamodified albumin and malondialdehyde. Data was analyzed using SPSS version 20. An Independent t-test was used to compare values between the groups during the third trimester. A pvalue of ≤0.05 was considered significant. Comparison of ischemia-modified albumin and malondialdehyde values between group I and group 2 showed a highly significant difference of pvalue of <0.001. Oxidative stress markers were higher in preeclamptic patients as compared to normal pregnant females during the third trimester suggesting the role of the placenta in oxidative stress.

Scanning drift tube measurements and kinetic studies of electron transport in CO

We present scanning drift tube measurements of electron swarm transport coefficients in CO as a function of the reduced electric field at room temperature under time-of-flight conditions. The measurements are compared to modeling results and other available experimental data on swarm transport over the broad range of from 2 Td to 1603 Td. The modeling results are obtained in Monte Carlo simulations and by solving the electron Boltzmann equation using a multi-term approach and the density gradient expansion procedure. We find generally good agreement between the measured and calculated transport coefficients. We propose a strategy to improve the cross-section set used to explain certain discrepancies at lower values. Measurements and calculations of electron transport coefficients under hydrodynamic conditions are complemented by Monte Carlo simulations of electron transport in an idealized steady-state Townsend (SST) setup. The ionization coefficient is calculated as a function of from the spatial density profiles of the electrons and compared to the corresponding values evaluated from the knowledge of the effective ionization frequency, drift velocity and longitudinal diffusion coefficient. Contrary to the traditional views, according to which the spatial relaxation of the mean energy and other transport properties for electrons in molecular gases is most commonly monotonic or quasi-monotonic, we find a ‘window’ of where the SST transport properties of the electrons exhibit oscillatory behavior as they relax towards the equilibrium state far downstream from the electron emitting boundary.

Centrally Acting ACE Inhibitor Use and Physical Performance in Older Adults

BackgroundThere is conflicting evidence regarding the role of angiotensin-converting enzyme inhibitors and physical function. While some studies show improvements in muscle strength and physical function, others show no significant difference or decreased performance. This ambiguity could be due to differential effects of angiotensin-converting enzyme inhibitor subtypes which can be categorized as centrally or peripherally-acting based upon their ability to cross the blood-brain barrier.ObjectiveThe objective of this study is to compare physical performance measures among angiotensin-converting enzyme inhibitor subtype users.MethodsDesign: Cross-sectional Setting: Ambulatory Participants: Performed in 364 participants in the Health and Retirement Study cohort who were ≥ 65 years (median age (IQR) 74.00 (69–80) years. Measurements: Average difference in hand grip (kg), gait speed(m/s) and peak expiratory flow (L/min).ResultsCompared to participants on a peripherally-acting angiotensin-converting enzyme inhibitor (113 (31%)), those on a centrally-acting agent (251(69%)) had stronger grip strength 28.9 ±1.0 vs 26.3±1.0, p=.011 and higher peak expiratory flow rates 316.8±130.4 vs. 280.0±118.5, p=.011 in unadjusted analysis. After multiple adjustments the difference in PEF remained statistically significant (Estimate(CI) 26.5, 95% CI 2.24, 50.5, p = 0.032).ConclusionOur results suggest that in older adults the use of centrally-acting angiotensin-converting enzyme inhibitors compared to a peripherally acting angiotensin-converting enzyme inhibitors was associated with better lung function in older individuals.

Complete collision data set for electrons scattering on molecular hydrogen and its isotopologues: IV. Vibrationally-resolved ionization of the ground and excited electronic states

We present a comprehensive set of vibrationally-resolved cross sections for electron-impact ionization of molecular hydrogen and its isotopologues (H2, D2, T2, HD, HT, and DT) in both the ground and excited electronic states. We apply the adiabatic-nuclei molecular convergent close-coupling (MCCC) method to calculate cross sections from threshold to 1000 eV for ionization of the ground and excited vibrational levels of the X1Σg+, B1Σu+, C1Πu, EF1Σg+, a3Σg+, and c3Πu electronic states, representing all states with united-atoms-limit principle quantum number n=1–2. The cross sections are presented in graphical form and provided as both numerical values and analytic fit functions in supplementary data files. The data can also be downloaded from the MCCC database at mccc-db.org.

Diagnostic Validity of Leucocyte Esterase Dipstick Tests for Spontaneous Bacterial Peritonitis in Patients with Cirrhosis

Background: One of the worst sequelae of cirrhosis and ascites is spontaneous bacterial peritonitis (SBP). Early detection and treatment of SBP are therefore essential for survival because this complication is linked to a high death risk if antibiotics are not administered promptly. Leukocyte esterase dipstick testing can identify the SBP quickly. Objective: To evaluate the diagnostic accuracy of leucocyte esterase dipstick test for the detection of spontaneous bacterial peritonitis taking ascitic fluid neutrophil count as gold standard. Study Design: Cross Sectional Study Settings: Department of Gastroenterology, Lady Reading Hospital, Peshawar Study Duration: This study was conducted from 1st July 2021 till 30th June 2022 Materials and Methods: Two samples (10cc each) of ascitic fluid aspirate were obtained from patients with cirrhosis on admission to the hospital, presenting with ascites, fever and abdominal pain. Bedside leucocyte esterase dipstick test was performed on one sample and the other was sent to hospital laboratory for ascitic fluid analysis for neutrophil count. The results of both modalities were compared diagnostic accuracy which was recorded in terms of sensitivity, specificity, positive predictive value and negative predictive. Results: Mean age of the patients was 46.68 ± 10.239 years. A total of 170 patients were enrolled. Age of the patients ranged from 18 to 75 years. Male patients were 113 (66.5%) while 57 patients (33.5%) were female. Hepatitis C was the leading cause of cirrhosis observed in 89 patients (52.4%). The sensitivity, specificity, positive and negative predictive value of leucocyte esterase dipstick test observed were 89.7%, 96.2%, 87.5% and 96.9% respectively. Conclusion: Leucocyte esterase dipstick test is a convenient, inexpensive and rapid diagnostic modality for SBP with better diagnostic accuracy. Keywords: Spontaneous Bacterial Peritonitis, Leucocyte Esterase Dipstick test, Diagnostic Accuracy.

Papillary Carcinoma in a Patient with a Thyroid Nodule: Role of Ultrasonography and its Diagnostic Accuracy

Introduction: While it can be difficult to categorize thyroid lesions, employing ultrasound may enable correct diagnosis, classification, and therapy of thyroid nodules, particularly papillary carcinoma of the thyroid, and assist save unneeded biopsy. Objective: Taking histopathology as the gold standard, assessing the diagnostic precision of ultrasound in the identification of papillary cancer in thyroid nodule patients. Study design: Cross sectional study Study Settings: Department of ENT &amp; Surgery, Jinnah Teaching Hospital, Peshawar Study Duration: This study was conducted from 1st August 2021 till 30th June 2022. Materials and Methods: Patients of both gender who sought assessment for a thyroid nodule were included. On ultrasonography, papillary carcinoma was detected. The gold standard for diagnosing cancers, histology, was used to confirm papillary carcinoma. Using a 2×2 table, diagnostic accuracy was assessed in terms of sensitivity, specificity, PPV, and NPV. Results: Overall 241 participants recruited. The patients were between the ages of 18 and 75. The patients' mean age was 57.80 + 9.245 years. The ratio of men to women was 1.2:1. The ultrasound's sensitivity, specificity, PPV, NPV, and diagnostic accuracy for the diagnosis of papillary thyroid cancer were, respectively, 85.1%, 97.5%, 88.8%, 96.5%, and 95.1%. Conclusion: With clinically significant diagnostic accuracy for the early diagnosis of thyroid papillary carcinoma, ultrasound is a cost-effective, non-invasive diagnostic method that may lessen the need for invasive diagnostic methods like thyroid biopsy. Keywords: Papillary Carcinoma of Thyroid, Ultrasound, Diagnostic Accuracy

Frequency of Perinatal Depression in Pregnant Women Utilizing Edinburgh Postnatal Depression Scale

Objective: To determine the frequency of perinatal depression in pregnant women utilizing Edinburgh Postnatal depression scale (EPDS). Study Design: Cross-sectional study Settings: Out-patient Department of Obstetrics and Gynecology, Combined Military hospital, Lahore. Duration of study: 1st November 2018 to 30th April 2019 Total 254 patients were selected. Patients were questioned according to EPDS scale and information recorded on prescribed form. Data was stratified for age, parity, gestational age, education level, and income group. Pregnant women with an EPDS score of ≥9 were considered to be suffering with depression. Results: In this present study a total of 254 women were interviewed for perinatal depression. The mean age of the patients was 27.64 ±8.89 years with minimum and maximum ages of 20 years and 34 years respectively. The mean gestational age of the patients was 38.31±2.16 weeks with a minimum and maximum gestational age of 37.40 and 40.02 respectively. In the study a total of 254 women were assessed for perinatal depression. 19.2% of women were found to be suffering from perinatal depression. Conclusion: “The results of our study demonstrate that, both antepartum and postpartum depression, in pregnant women are significantly prevalent.” Keywords: “Edinburgh Postnatal depression scale (EPDS), perinatal depression, low-income countries (LIC), high-income countries (HIC).”

Impact of Smoking on High and Low-Grade Urothelial Carcinoma

Objectives: This study was done to evaluate the role of smoking in high- and low-grade urothelial carcinoma. Study design: Cross-sectional descriptive study Study setting: This cross-sectional study was done at the Department of histopathology, Liaquat University of Medical and Health sciences, Jamshoro, Pakistan. Methods: Total 165 cases of urothelial carcinoma were included in this study. The clinical history of patients was taken from computer storage data followed by review of microscopic slides by two histopathologists. Excel 2021 and SPSS 22 were used for statistical analysis. Results: A total of 165 cases were enrolled in the study. 55.15% (n=91) were smokers. Smoking history was positive in most cases of low-grade urothelial carcinoma. Follow up of patients was taken at 24 months after biopsy or resection of tumor. Patient with high grade urothelial carcinoma poor outcome i.e., 53.3% dead at the follow up taken at 24 months. Conclusion: In conclusion, urothelial carcinoma is an aggressive malignancy which has strong association with smoking. Patients with positive smoking history present with higher stage and grade of disease. Early intervention in form of strict follow up and smoking cessation should be done in patients to ensure prompt treatment. Keywords: High grade urothelial carcinoma, Low grade urothelial carcinoma, Smoking

Managerial talent and managerial practices: Are they complements?

We examine the role of managerial talent and its interaction with managerial practices in determining firm performance. We build a matched firm-director panel dataset for the universe of limited liability companies in Italy, tracking directors across different firms over time. We define managerial talent as the individual contribution to the variation of the firms’ total factor productivity, estimated using a two-way fixed effects model. Combining the data with survey information on a representative sample of firms, we then document that our measure of talent correlates with ex-ante and ex-post indicators of ability, i.e. managers’ educational attainment and their forecast precision with respect to the firm’s future performance. Most important, we leverage information on the adoption of managerial practices within the firm to examine potential synergies between managerial talent and structured managerial practices, thus bridging two separate strands of the literature. While talent and structured practices are positively associated with firm productivity on their own, there is evidence of complementarities between the two. These findings hold both in a cross-sectional setting and in a panel analysis that accounts for time-invariant firm heterogeneity. Overall, our results indicate that the effectiveness of managerial practices varies with managers’ ability to implement them.

Antiproton collisions with excited positronium

We present results of calculations of several processes resulting from positronium (Ps) collisions with antiprotons: antihydrogen formation, Ps breakup, and ${n}_{\mathrm{Ps}}$-changing collisions. Calculations utilize the quantum convergent close-coupling (CCC) method and the classical trajectory Monte Carlo (CTMC) method. We identify a region of Ps principal quantum numbers ${n}_{\mathrm{Ps}}$ and Ps energies where the classical description is valid and where the CCC calculations become computationally too expensive. This allows us to present the most complete and reliable set of cross sections in a broad range of ${n}_{\mathrm{Ps}}$ and initial orbital momentum quantum numbers ${l}_{\mathrm{Ps}}$ which are necessary for experiments with antihydrogen at CERN.

Significance of Fib4 index as an indicator of alcoholic hepatotoxicity in health examinations among Japanese male workers: a cross-sectional and retrospectively longitudinal study

BackgroundFib4 index (Fib4) is clinically used as a noninvasive marker of liver fibrosis. In this study, we aimed to preliminarily investigate whether Fib4 can be used to detect individuals who need assessment for alcoholic liver disease (ALD) in the general population by clarifying the detailed association of Fib4 with alcohol consumption and gamma-glutamyl transferase (GGT) among male workers.MethodsWe analyzed data sets on the comprehensive medical examinations of male workers as cross-sectional and retrospectively longitudinal studies. We enrolled 10 782 males (mean age: 52.2 ± 10.2 years) in FY2019 and 7845 males (mean follow-up: 12.6 ± 6.7 years) who could be consecutively followed up for 20 years from FY2000 to FY2019. Data were evaluated using logistic regression and COX proportional analysis.ResultsIn the cross-sectional setting, the rate of Fib4 ≥ 2.67 in heavy drinkers (≥ 40 g of ethanol/day) was increased dose dependently in those over 65 years old, and that of body mass index ≥ 30 kg/m2 was increased in those over 60 years old, but not in those with fatty liver. The odds ratio (OR) (95% confidence interval [CI]) for heavy drinking was 4.30 (95% CI = 1.90–9.72), and GGT ≥ 200 IU/L was considerably high (OR = 29.05 [95% CI = 17.03–49.56]). In the longitudinal setting, heavy drinkers and those with GGT ≥ 200 IU/L at 10 years after the baseline showed an increased risk for Fib4 ≥ 2.67 (hazard ratio = 2.17 [95% CI = 1.58–2.98] and 7.65 [95% CI 5.26–11.12], respectively).ConclusionsThe development of Fib4 ≥ 2.67 after 10 years was associated with heavy alcohol drinking and GGT level ≥ 200 IU/L. Therefore, Fib4 combined with GGT could indicate high risk of ALD. However, clinical examinations and course observations are essentially needed.