Chen Feng

Chinese mind-body exercises are positively associated with executive function, but their effects on EF, from synthesized evidence using systematic and meta-analytic reviews, have not been conducted. Therefore, the present systematic review with meta-analysis attempted to determine whether CMBEs affect EF and its sub-domains, as well as how exercise, sample, and study characteristics moderate the causal relationship between CMBEs and EF in middle-aged and older adults. Seven electronic databases were searched for relevant studies published from the inception of each database through June 2020. Randomized controlled trials with at least one outcome measure of CMBEs on EF in adults of mean age ≥ 50 years with intact cognition or mild cognitive impairment and with or without chronic diseases were included. A total of 29 studies ultimately were included in this study. The results indicated that CMBEs improved overall EF, as well as its sub-domains of working memory and shifting. The beneficial effects of CMBEs on EF occurred regardless of type, frequency of group classes, session time, total training time, and length of the CMBEs, in addition to that more frequent participation in both group classes and home practice sessions resulted in more beneficial effects. The positive effects of CMBEs on EF were also demonstrated, regardless of participants mean age, sex, and cognitive statuses, health status, as well as training mode and study language. This review thus suggests that CMBEs can be used as an effective method with small to moderate and positive effects in enhancing EF, and that more frequent group classes and home practice sessions may increase these effects. However, certain limitations, including strictly design studies, limited ES samples for specific variables, and possible biased publications, required paying particular attention to, for further exploring the effects of CMBEs on EF.

The fiscal imbalance between the central and local governments under fiscal centralization may motivate local governments to pass tax burdens on firms. The causal identification of the tax system reform and the sustainable export innovation behavior of firms are of great significance. This study uses the income tax sharing policy of China to examine the impact of fiscal centralization on the sustainable export innovation behavior of firms. We find that this tax reform has significantly inhibited the increase of the export value-added rate of firms, and has an increasing trend with the share ratio between the Central Government and the local government. Moreover, this effect mainly comes from the crowding-out effect of imported intermediate goods on domestic intermediate goods. The tests show that the above conclusions are consistent with the general logic of local governments. When they face greater downward fiscal pressure, they will further pass the tax burden on local firms and force the firms to promote their export performance to expand the tax base. This short-sighted behavior of replacing “quality improvement” with “quantity increase” is an important factor that affects the sustainable export innovation behavior of firms and the climb in the global value chain.

With renewable energy being increasingly connected to power grids, pumped storage plants play a very important role in restraining the fluctuation of power grids. However, conventional control strategy could not adapt well to the different control tasks. This paper proposes an intelligent nonlinear model predictive control strategy, in which hydraulic-mechanical and electrical subsystems are combined in a synchronous control framework. A newly proposed online sequential extreme learning machine algorithm with forgetting factor is introduced to learn the dynamic behaviors of the coupling system. Specifically, the initial learning parameters are optimized by prior-knowledge learning and a new self-adaptive adjustment strategy is also put forward. Subsequently, the stair-like control strategy and artificial sheep algorithm are used in rolling the optimization mechanism to replace the existing complex differential geometric solutions. Comparative experiments are carried out under different working conditions based on a PSP in China. The results show that the influence from coupling factors can be considerable and the proposed MPC strategy indicates superiority in voltage and load adjustment as well as the frequency oscillation suppression.

ObjectiveThis study used a moderated mediation model to test the mediating effect of anxiety on the relationship between negative perfectionism and sleep quality and the moderating effect of COVID-19 epidemic risk perception during the COVID-19 pandemic in Chinese international students.Materials and methodsA sample of 239 Chinese international students from the south of China, was surveyed with the Negative and Positive Perfectionism Scale, the Pittsburgh Sleep Quality Index, the General Anxiety Disorder Scale, and the COVID-19 Epidemic Risk Perception Inventory. Version 23.0 of SPSS and version 3.4 of PROCESS were used to perform the correlation analyses, mediation analysis, and moderated mediation analysis.Results Negative perfectionism was significantly correlated with anxiety and poor sleep quality. Anxiety was significantly correlated with poor sleep quality. The mediating effect test showed that anxiety had a mediating effect between negative perfectionism and poor sleep quality. Epidemic risk perception moderated the mediating effect of anxiety between negative perfectionism and poor sleep quality.ConclusionNegative perfectionism affected sleep quality indirectly through anxiety. In particular, COVID-19 epidemic risk perception moderated the relationship between anxiety and sleep quality, such that the association was stronger when the COVID-19 epidemic risk perception was high. These results provide a more comprehensive understanding of the negative link between negative perfectionism and poor sleep quality.