Early detection of the risk of developing psychiatric disorders: a study of 461 Chinese university students under chronic stress

Chronic stress, a characteristic of modern time, has a significant impact on general health. In the context of psychiatric disorders, insufficient coping behavior under chronic stress has been linked to higher rates of (1) depressive symptoms among subjects of the general population, (2) relapse among patients under treatment for clinical depression, and (3) negative symptoms among subjects with an elevated vulnerability to psychosis. In this normative study we assessed basic coping behavior among 461 Chinese freshman university students along with their consumption behavior and general health in terms of regular exercises, physical health, psychosomatic disturbances, and mental health. The assessments relied on two instruments that have already demonstrated their capability of (1) reliably detecting insufficient coping behavior under chronic stress and (2) reliably quantifying the interrelation between coping behavior and mental health in the Western world. Thus, we aimed to complement existing data and to develop a generally available, socioculturally independent tool that can be used for the early detection of subjects with an elevated risk of mental health problems. Structural analyses yielded essentially the same scales "activity" and "defeatism" as previous studies on 2,500 students from Switzerland, Italy, Spain, the USA, and Argentina. These scales explained 74.3% of the observed variance in coping behavior among the 461 Chinese students. We found highly significant correlations (p < 0.0001) between the "defeatism" scale on the one hand, and the scales "regular use of medicine," "psychosomatic disturbances," and "impaired mental health" on the other. Particularly intriguing was the finding that a neural net classifier could be constructed to identify students with the highest contributions to the interrelation between "coping behavior" and "mental health," yielding a correlation coefficient as high as r = 0.597 for the respective subgroup. Based on the normative data, an online tool for risk assessments was developed with immediate feedback to users. This study provided another piece of evidence regarding the close link between basic coping behavior and mental health, across cultures and ethnicities. In consequence, our approach to quantifying basic coping behavior, along with other risk factors, can be expected to clear the way for an "early" detection of students with an elevated risk of stress-related mental health problems, nota bene prior to the development of clinically relevant symptoms. The socioeconomic impact of the potential prevention of depressive -disorders, and psychiatric disorders in general, may be enormous

A non-equilibrium slip wall model for large-eddy simulation with an immersed boundary method

A non-equilibrium wall model for large-eddy simulation with the immersed boundary (IB) method is proposed to reduce the required number of grid points in simulating wall-bounded turbulence. The proposed wall model is presented as an appropriate slip velocity on the wall. The slip velocity is constructed by integrating the simplified turbulent boundary layer (TBL) equation along the wall-normal direction, which enhances the integral momentum balance near the wall on a coarse grid. The effect of pressure gradient on the near wall flow is taken into account by retaining the pressure gradient term in the simplified TBL equation. The proposed model is implemented in the form of a direct-forcing IB method with moving-least-square reconstruction near the wall. The benchmarks of plane channel turbulence and the flows over a backward-facing step are used for validation. The proposed model improves the wall stresses and velocity profiles in the region where the pressure gradient dominates the near wall flows. (C) 2022 Author(s)

Optimal reduced frequency for the power efficiency of a flat plate gliding with spanwise oscillations

The spanwise oscillation provides an accessory or alternative to flapping motion toward high-efficiency bio-inspired flight. The power factor that measures the efficiency of a gliding wing with spanwise oscillation to support a unit weight is investigated in this work. The gliding wing model consists of a rectangular flat plate that oscillates sinusoidally along the spanwise direction in a uniform upstream flow at a post-stall angle of attack. The unsteady flows and aerodynamic forces are obtained by numerically solving the incompressible Navier-Stokes equations at a Reynolds number of 300 (based on the uniform upstream velocity and the chord length). It is found that the spanwise oscillation can effectively enhance the power factor of the rectangular wing. The power factor under the optimal spanwise oscillation is 1.97 times as large as that without spanwise oscillation. Then, we introduce an effective reduced frequency by accounting for the effect of spanwise oscillation on the velocity encountered by the wing. The results show that the optimal effective reduced frequency locates in a narrow region from 0.47 to 0.56. Finally, the analyses of the vortex structures and the Lamb vector field indicate that the enhanced power factor results from the interaction between the stable leading-edge vortex and side-edge vortices associated with the spanwise oscillation. This work is expected to be helpful in understanding the vortex dynamics and guiding the kinematic design of the high-efficiency bio-inspired flight with spanwise oscillation

Artificial neural network based response surface for data-driven dimensional analysis

The classical dimensional analysis method has limitations in determining the uniqueness and relative importance of the dimensionless quantities. A machine-learning based dimensional analysis method is proposed to address the limitations. The proposed method identifies unique and relevant dimensionless quantities by combining an artificial neural network with the data-driven dimensional analysis. We employ a fully connected neural network to construct the ridge function for the response surface in a physical system. The gradient of the response surface for active subspace analysis is computed based on a finite difference approximation. An effective approach is proposed to determine the independent variables of experimental measurements or numerical simulations for computing the gradient of the response surface. The proposed method is validated by analyzing benchmark pipe flows and a fluid-structure interaction system. The dominant dimensionless quantities obtained by the proposed method are consistent with those reported in the literature. The proposed method has the advantage of identifying the relatively important dimensionless quantities without referring to the complex theoretical equations. (C)& nbsp;2022 Elsevier Inc. All rights reserved

Design and Analysis of Brake-by-Wire Unit Based on Direct Drive Pump–Valve Cooperative

Aiming at the requirements of distributed braking and advanced automatic driving, a brake-by-wire unit based on a direct drive pump–valve cooperative is proposed. To realize the wheel cylinder pressure regulation, the hydraulic pump is directly driven by the electromagnetic linear actuator coordinates with the active valve. It has the advantages of rapid response and no deterioration of wheel side space and unsprung mass. Firstly, by analyzing the working characteristics and braking performance requirements of the braking unit, the key parameters of the system are matched. Then, in order to ensure the accuracy of the simulation model, the co-simulation model of the brake unit is established based on the Simulink-AMESim co-simulation platform. Then, the influence law of key parameters on the control performance is analyzed. Finally, the experimental platform of the brake unit is established. The accuracy of the co-simulation model and the feasibility of the brake-by-wire unit based on direct drive pump–valve cooperative are verified through the pressure control experiment and ABS simulation, which shows that the braking unit has good dynamic response and steady-state tracking effect

Vulnerability and Burden of All-Cause Mortality Associated with Particulate Air Pollution during COVID-19 Pandemic: A Nationwide Observed Study in Italy

Background: Limited evidence is available on the health effects of particulate matter (PM including PM2.5 with an aerodynamic diameter ≤ 2.5 μm; PM10, ≤ 10 μm; PM2.5–10, 2.5–10 μm) during the pandemic of COVID-19 in Italy. The aims of the study were to examine the associations between all-cause mortality and PM in the pandemic period and compare them to the normal periods (2015–2019). Methods: We collected daily data regarding all-cause mortality (stratified by age and gender), and PM concentrations for 107 Italian provinces from 1 January 2015 to 31 May 2020. A time-stratified case-cross design with the distributed lag non-linear model was used to examine the association between PM and all-cause mortality. We also compared the counts and fractions of death attributable to PM in two periods. Results: Italy saw an increase in daily death counts while slight decreases in PM concentrations in pandemic period. Each 10 µg/m3 increase in PM was associated with much higher increase in daily all-cause mortality during the pandemic period compared to the same months during 2015–2019 (increased mortality rate: 7.24% (95%CI: 4.84%, 9.70%) versus 1.69% (95%CI: 1.12%, 2.25%) for PM2.5; 3.45% (95%CI: 2.58%, 4.34%) versus 1.11% (95%CI: 0.79%, 1.42%) for PM10; 4.25% (95%CI: 2.99%, 5.52%) versus 1.76% (95%CI: 1.14%, 2.38%) for PM2.5–10). The counts and fractions of deaths attributable to PM were higher in 2020 for PM2.5 (attributable death counts: 20,062 versus 3927 per year in 2015–2019; attributable fractions: 10.2% versus 2.4%), PM10 (15,112 versus 3999; 7.7% versus 2.5%), and PM2.5–10 (7193 versus 2303; 3.7% versus 1.4%). Conclusion: COVID-19 pandemic increased the vulnerability and excess cases of all-cause mortality associated with short-term exposure to PM2.5, PM2.5–10, and PM10 in Italy, despite a decline in air pollution level

In-situ rock tests for fault gouge zone：A case in Fengman hydropower station, China

The existence of faults in the dam site area threatens the stability and safety of large-scale hydropower projects in China. The fault argillaceous zone is the worst kind of fault fracture zone, and the determination of its deformation and strength parameters is the key point of rock engineering investigation. In this study, the in-situ bearing plate test and direct shear test were carried out on the gouge zone of F67 fault in the dam site of Fengman Hydropower Station. The test results show that the deformation and shear law of each test point is good, which is basically consistent with the actual condition of the measured rock mass. However, due to the limited number of measurements, the results are limited in terms of macroscopic representation. The experimental results provide scientific basis for subsequent engineering design and further enhance the understanding of mechanical properties of fault gouges

Removal of organics by combined process of coagulation–chlorination–ultrafiltration: optimization of overall operation parameters

<p>To gain the run parameters of the combined process of coagulation/<i>in situ</i> chlorination/ultrafiltration (UF) so that the system can remove as much organic contaminants as possible without serious membrane fouling, the impacts of operation conditions in coagulation and pre-chlorination unit were investigated in a pilot-scale test. The characteristics of organics in UF influent were examined by excitation emission matrix spectroscopy to find out fouling behavior of different natural organic matter compositions to UF membrane. Thereafter, the operation parameters of different processing units of the hybrid device were optimized by response surface methodology (RSM). The results showed that the tests with the agitation speed of 40 r min⁻¹ had the lowest membrane fouling rate and the highest COD_Mn removal, in addition, inappropriate dosage of sodium hypochlorite in membrane influent might exert negative impacts on membrane by lowering UV₂₅₄ rejection, especially during the high algae laden period. The predominant factors of membrane fouling were the existence of tryptophan protein-like substances and the soluble microbial products. Optimum values of the mechanical rotation speed in coagulation unit, chemical dosage in pre-chlorination unit, and membrane flux in UF unit of the integrative process were 41.79 r min⁻¹, 1.40 mg L⁻¹, and 82.26 LMH, respectively.</p

Design of a Fiber Bragg Grating Pressure Sensor Based on a Metal Diaphragm and Lever Structure

In this paper, a pressure sensor based on a metal diaphragm and lever structure is designed, the sensing principle and mechanical structure of this sensor are analyzed and simulated, and its sensitization effectiveness and temperature compensation are verified. The maximum deflections of metal diaphragms of different sizes and materials were compared, and it was found that the square beryllium bronze diaphragm with a thickness of 1 mm and a side length of 20 mm had good elastic properties. The influence of the FBG in different positions of the lever on the center wavelength is analyzed. The sensitivity of the bare FBG is markedly improved under the influence of the two structures of the square elastic diaphragm and the lever, with a typical pressure sensitivity of 3.35 nm/MPa at 3 mm to the left of the lever center. The purpose of temperature compensation is achieved by adding another FBG that measures the temperature, and the sensing sensitivity can be tuned by adjusting the position of the FBG. It can meet the detection needs of a small range and high sensitivity