Four extreme haze episodes occurred in October 2014 in the North China Plain (NCP). To clarify the formation mechanism of hazes in autumn, strengthened observations were conducted in Beijing from 5 ...October to 2 November. The meteorological parameters, satellite data, chemical compositions and optical properties of aerosols were obtained. The hazes originated from the NCP, developing in the southwest and northeast directions, with the highest concentration of PM2.5 of 469 mu g m-3 in Beijing. The NCP was dominated by a weak high pressure system during the haze episode, which resulted in low surface wind speed and relatively stagnant weather. Moreover, the wind slowed down around Beijing city. The secondary aerosols NO3- was always higher than that of SO42-, which indicated the motor vehicles played a more important part in the hazes in October 2014, even though the oxidation rate from SO2 to SO42- was faster than that of NOx to NO3-. Sudden increases of the concentrations of organic matter, Cl- and BC (black carbon) before each haze episode implied that regional transport of pollutants by biomass burning was important for haze formation during autumn. A satellite map of fire points and the backward trajectories of the air masses also indicated this pollution source. The distinct decrease in the PBL (planetary boundary layer) height during four haze episodes restrained the vertical dispersion of the air pollutants. Water vapor also played a vital role in the formation of hazes by accelerating the chemical transformation of secondary pollutants, leading to hygroscopic growth of aerosols and altering the thermal balance of the atmosphere.
Summary
Background
Obesity, a comorbid medical condition, is usually observed in patients with established coronary artery disease. Paradoxically, patients with a higher body mass index (BMI) usually ...have better clinical outcomes after coronary revascularization.
Methods
We searched five online databases through December 2017. We identified studies reporting the rate of all‐cause mortality or cardiovascular‐related outcomes among patients after coronary revascularization with percutaneous coronary intervention or coronary artery bypass graft based on various BMI categories. Network meta‐analysis was performed using Bayesian methods.
Results
Sixty‐five records involving 865,774 participants were included in our study. A U‐shaped association was observed across BMI categories for all‐cause mortality. Using normal weight as the reference, all‐cause mortality was increased for (relative risk RR: 2.4; 95% credibility interval CrI: 2.1–2.7) patients with underweight, whereas it was lowered in patients with overweight, obese, and severely obese. This association remained significant in many subgroups. We also observed that the risk of major adverse cardiovascular events (MACE) was lowest among patients with overweight. Furthermore, patients with underweight were associated with greater risks of myocardial infarction (RR: 1.9; 95% CrI: 1.4–2.5), cardiovascular‐related mortality (RR: 2.8; 95% CrI: 1.6–4.7), stroke (RR: 2.0; 95% CrI: 1.3–3.3) and heart failure (RR: 1.7; 95% CrI: 1.1–2.7) compared with normal weight patients; no significant association was observed among individuals with higher BMI.
Conclusions
The ‘obesity paradox’ does exist in patients after coronary revascularization, especially for patients with post‐percutaneous coronary intervention. All‐cause mortality in patients with high BMI is significantly lower compared with patients with normal weight. Furthermore, patients with underweight experience higher rates of cardiovascular outcomes compared with patients with normal weight.
Abstract Objective This study investigates the relationship between hukou conversion and the psychological integration of rural older migrants, exploring the mediating role of accessibility to health ...resources. Methods The 3,963 valid samples of rural older migrants included in the study were sourced from the 2017 China Migrants Dynamic Survey (CMDS). The study established a multiple linear regression model for estimation and utilized inverse probability-weighted regression adjustment (IPWRA) method to correct for the selection bias of hukou conversion. Results Compared to older migrants with rural hukou , merit-based (β = 0.384, 95% CI: 0.265 to 0.504), family-based (β = 0.371, 95% CI: 0.178 to 0.565) and policy-based (β = 0.306, 95% CI: 0.124 to 0.487) converters have significantly higher psychological integration. These findings remain robust even after addressing the potential issue of endogenous selection bias using the IPWRA method. Bootstrap mediating effect tests indicate that hukou conversion can indirectly affect psychological integration through the mediator role of health resources accessibility. Conclusion Accessibility of health resources mediates the association between hukou conversion and psychological integration. Policymakers should enhance the implementation of hukou conversion, strengthen the health resource guarantee system, and achieve a deeper psychological integration among rural older migrants.
The long-lived 60Fe (with a half-life of 2.62 Myr) is a crucial diagnostic of active nucleosynthesis in the Milky Way galaxy and in supernovae near the solar system. The neutron-capture reaction ...59Fe(n,γ)60Fe on 59Fe (half-life = 44.5 days) is the key reaction for the production of 60Fe in massive stars. This reaction cross section has been previously constrained by the Coulomb dissociation experiment, which offered partial constraint on the E1 γ-ray strength function but a negligible constraint on the M1 and E2 components. In this work, for the first time, we use the surrogate ratio method to experimentally determine the 59Fe(n,γ)60Fe cross sections in which all the components are included. We derived a Maxwellian-averaged cross section of 27.5 ± 3.5 mb at kT = 30 keV and 13.4 ± 1.7 mb at kT = 90 keV, roughly 10%–20% higher than previous estimates. We analyzed the impact of our new reaction rates in nucleosynthesis models of massive stars and found that uncertainties in the production of 60Fe from the 59Fe(n,γ)60Fe rate are at most 25%. We conclude that stellar physics uncertainties now play a major role in the accurate evaluation of the stellar production of 60Fe.
Interaction between violent water waves and structures is of a major concern and one of the important issues that has not been well understood in marine engineering. This paper will present first ...attempt to extend the Meshless Local Petrov Galerkin method with Rankine source solution (MLPG_R) for studying such interaction, which solves the Navier–Stokes equations for water waves and the elastic vibration equations for structures under wave impact. The MLPG_R method has been applied successfully to modeling various violent water waves and their interaction with rigid structures in our previous publications. To make the method robust for modeling wave elastic–structure interaction (hydroelasticity) problems concerned here, a near-strongly coupled and partitioned procedure is proposed to deal with coupling between violent waves and dynamics of structures. In addition, a novel approach is adopted to estimate pressure gradient when updating velocities and positions of fluid particles, leading to a relatively smoother pressure time history that is crucial for success in simulating problems about wave–structure interaction. The developed method is used to model several cases, covering a range from small wave to violent waves. Numerical results for them are compared with those obtained from other methods and from experiments in literature. Reasonable good agreement between them is achieved.
This is the first paper to present a hybrid method coupling an Improved Meshless Local Petrov Galerkin method with Rankine source solution (IMLPG_R) based on the Navier–Stokes (NS) equations, with a ...finite element method (FEM) based on the fully nonlinear potential flow theory (FNPT) in order to efficiently simulate the violent waves and their interaction with marine structures. The two models are strongly coupled in space and time domains using a moving overlapping zone, wherein the information from both the solvers is exchanged. In the time domain, the Runge–Kutta 2nd order method is nested with a predictor–corrector scheme. In the space domain, numerical techniques including ‘Feeding Particles’ and two-layer particle interpolation with relaxation coefficients are introduced to achieve the robust coupling of the two models. The properties and behaviours of the new hybrid model are tested by modelling a regular wave, solitary wave and Cnoidal wave including breaking and overtopping. It is validated by comparing the results of the method with analytical solutions, results from other methods and experimental data. The paper demonstrates that the method can produce satisfactory results but uses much less computational time compared with a method based on the full NS model.
This paper reviews the developments and applications of meshfree method based on MLPG (Meshless Local Petrov Galerkin) in ocean engineering, primarily from the work carried out at IIT Madras and ...City, University of London, UK. Apart from discussing the various stages in the model development, this paper will also reports its applications to small amplitude waves, wave overtopping and breaking, porous layers, long wave run-up, vegetation, floating bodies in waves, wave interaction with elastic structure and two phase flow modelling. Generally, the Navier – Stokes equation will lead to numerical dissipation for long distance propagations and increase in computational time. In order to avoid this, one needs to look for a physics based approach. One of the successfully implemented approaches in MLPG was by coupling with fully nonlinear potential flow theory (FNPT), either one-way or two-way. In this paper, we bring out the advantages and implementation issues of MLPG. The paper also discuss the relationship with ISPH/MPS methods and some concepts that are adopted in both formulations. The paper ends with the key challenges and future directions in the development of the numerical method.
With wide applications, the smoothed particle hydrodynamics method (abbreviated as SPH) has become an important numerical tool for solving complex flows, in particular those with a rapidly moving ...free surface. For such problems, the incompressible Smoothed Particle Hydrodynamics (ISPH) has been shown to yield better and more stable pressure time histories than the traditional SPH by many papers in literature. However, the existing ISPH method directly approximates the second order derivatives of the functions to be solved by using the Poisson equation. The order of accuracy of the method becomes low, especially when particles are distributed in a disorderly manner, which generally happens for modelling violent water waves. This paper introduces a new formulation using the Rankine source solution. In the new approach to the ISPH, the Poisson equation is first transformed into another form that does not include any derivative of the functions to be solved, and as a result, does not need to numerically approximate derivatives. The advantage of the new approach without need of numerical approximation of derivatives is obvious, potentially leading to a more robust numerical method. The newly formulated method is tested by simulating various water waves, and its convergent behaviours are numerically studied in this paper. Its results are compared with experimental data in some cases and reasonably good agreement is achieved. More importantly, numerical results clearly show that the newly developed method does need less number of particles and so less computational costs to achieve the similar level of accuracy, or to produce more accurate results with the same number of particles compared with the traditional SPH and existing ISPH when it is applied to modelling water waves.
Crop and animal production in China has increased significantly during the last decades, but at the cost of large increases in nitrogen (N) and phosphorus (P) losses, which contribute to ecosystem ...degradation and human health effects. This information is largely based on scattered field experiments, surveys and national statistics. As a consequence, there is as yet no comprehensive understanding of the changes in N and P cycling and losses at regional and national scales.
Here, we present the results of an integrated assessment of the N and P use efficiencies (NUE and PUE) and N and P losses in the chain of crop and animal production, food processing and retail, and food consumption at regional scale in 1980 and 2005, using a uniform approach and databases. Our results show that the N and P costs of food production–consumption almost doubled between 1980 and 2005, but with large regional variation. The NUE and PUE of crop production decreased dramatically, while NUE and PUE in animal production increased. Interestingly, NUE and PUE of the food processing sector decreased from about 75% to 50%. Intake of N and P per capita increased, but again with large regional variation. Losses of N and P from agriculture to atmosphere and water bodies increased in most regions, especially in the east and south of the country. Highest losses were estimated for the Beijing and Tianjin metropolitan regions (North China), Pearl River Delta (South China) and Yangzi River Delta (East China).
In conclusion, the changes and regional variations in NUE and PUE in the food chain of China are large and complex. Changes occurred in the whole crop and animal production, food processing and consumption chain, and were largest in the most populous areas between 1980 and 2005.
► The 1st integrated assessment of N and P use efficiencies in the food chain in China. ► The mean cost of 1kg N and 1kg P in Chinese food is 11kg N and 13kg P. ► N and P use efficiencies decreased in crop production and food processing. ► N and P use efficiencies increased in animal production. ► Total N and P losses from agriculture strongly increased between 1980 and 2005.
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