Learning burnout is a pressing issue among Chinese medical undergraduates and Postgraduates and has drawn continuous attention worldwide. Studies have found that problematic smartphone use could ...affect learning burnout, but more research is needed in this direction. Furthermore, few studies focused on the mediating effect of psychological capital on the relationship between problematic smartphone use and learning burnout. The present study was a cross-sectional survey that recruited 1,800 participants from a medical university in Chongqing, China. A questionnaire based on the Mobile Phone Addiction Tendency Scale, Psychological Capital Questionnaire, Learning Burnout Scale, and demographic variables were administered to these students, and 1,475 provided valid responses (81.94%). 771 were undergraduates (52.3%) and 704 were postgraduates (47.7%). Hierarchical regression and the bootstrap method were used to examine the mediating effect of psychological capital. After controlling for demographic variables, problematic smartphone use positively predicted learning burnout in undergraduates (β = 0.328,
p
< 0.01) and in postgraduates (β = 0.342,
p
< 0.01). The partial mediating effect of psychological capital was 0.068 in undergraduates and 0.074 in postgraduates, accounting for 20.67 and 21.64%, respectively, of the total effect of problematic smartphone use on learning burnout. All the 95% confidence intervals (CI) did not contain 0. Problematic smartphone use can directly predict learning burnout and their relationship was mediated by psychological capital in Chinese medical undergraduates and postgraduates. Strategies to alleviating problematic smartphone use and enhance psychological capital in medical undergraduates and postgraduates may provide useful suggestions for future interventions on dealing with learning burnout in Chinese medical undergraduates and postgraduates.
A broadband dual circularly polarized patch antenna with wide beamwidth is presented. The patch is excited by four cross slots via a microstrip line with multiple matching segments underneath the ...ground plane. The four cross slots and the multiple matching segments are optimized simultaneously to obtain the best performance. Measurements show that the antenna has 10-dB return-loss bandwidth of 24%, 10-dB isolation bandwidth of 19%, 3-dB axial-ratio bandwidth of 16%, and beamwidth of 110 ° . Moreover, the single feed makes it a good candidate for array design.
In this study, a single‐microstrip‐fed S‐shaped magneto‐electric (ME) dipole array with broadband circular polarisation is presented for millimetre wave (MMW) applications. The ME dipole is composed ...of four S‐shaped patches and metalised via holes. The patches are sequentially fed by a single microstrip ring with four impedance matching sections underneath the patches through four via holes. The proposed antenna achieves a 32.7% impedance bandwidth (IBW), 25.7% axial‐ratio bandwidth (ARBW), maximum gain of 8 dBic and low profile of 0.1 λ0 (λ0 is the free space wavelength referring to 28 GHz), which decreases to 40% of general ones with a profile of 0.25 λ0. To confirm the superiority of the antenna, a compact 2 × 8 array with the dimension of 7.8 λ0 × 3 λ0 × 0.1 λ0 is fabricated on two substrate layers. Experimental results show that the IBW is 37% covering 22–32 GHz, ARBW for axial ratio (AR) smaller than 3.4 dB is 26.9% covering 22.5–29.5 GHz, maximum gain is 18.5 dBic, and aperture radiation efficiency (ARE) is better than 70%. In addition, the basic element with excellent performance is single‐microstrip‐fed and easily expandable to any size, which makes it a promising candidate that can be adopted in MMW bands.
The impact of high-standard basic farmland construction policies on agricultural eco-efficiency has been extensively considered. Using the Chinese provincial panel data from 2007–2017, we first ...measure the level of agricultural eco-efficiency in China by employing data envelopment analysis. Then, using difference-in-difference models, we analyze the impact of high-standard basic farmland construction policies on agricultural eco-efficiency and test whether there is heterogeneity of this impact. Finally, we further explore the specific channels through which the polices of high-standard basic farmland construction affect agricultural eco-efficiency. The empirical results indicate that 1) the implementation of high-standard farmland construction policies can significantly improve agricultural eco-efficiency, 2) the heterogeneity of the impact of high-standard farmland construction policies on agricultural eco-efficiency is manifested in both regional and efficiency aspects and 3) high-standard farmland construction policies promote agricultural eco-efficiency through the interaction between the new land scale and the replanting index.
Purpose:
Our purpose was to investigate the effect of lncRNA MEF2C antisense RNA 1 (MEF2C-AS1) on cervical cancer and further explore its underlying molecular mechanisms.
Methods:
The proliferation, ...migration and invasion of CC cells were determined by counting Kit-8 (CCK-8), colony formation assay, and transwell assays, respectively. qRT-PCR and western blot were conducted to quantitatively detect the expression of lncRNA MEF2C-AS1, miR-592 and R-spondin1 (RSPO1). Kaplan-Meier survival curve from the Cancer Genome Atlas (TCGA) database and the Gene Expression Profiling Interactive Analysis (GEPIA) website was used to describe the overall survival. Bioinformatics analysis was performed to search the downstream target of lncRNA MEF2C-AS1 and miR-592. Luciferase reporter assay was conducted to detect the interaction between lncRNA MEF2C-AS1 and miR-592 or miR-592 and RSPO1.
Results:
The data from GEPIA website showed that lncRNA MEF2C-AS1 expression was down-regulated in CC tissues and also associated with survival rate of CC patients. Moreover, the results of qRT-PCR also showed lncRNA MEF2C-AS1 was lowly expressed in CC cells. Subsequently, we confirmed that overexpression of lncRNA MEF2C-AS1 inhibited the proliferation, migration and invasion of CC cells. Further research illustrated that lncRNA MEF2C-AS1 was the target of miR-592, and RSPO1 was the downstream target gene of miR-592. Importantly, functional research findings indicated that lncRNA MEF2C-AS1 inhibited CC via suppressing miR-592 by targeting RSPO1.
Conclusion:
In our study, we demonstrated the functional role of the lncRNA MEF2C-AS1-miR-592-RSPO1 axis in the progression of CC, which provides a latent target for CC treatment.
At present, the rapid development of digital finance is closely related to the economic development of urban agglomerations. An urban agglomeration provides conditions for digital finance to form a ...spatial relevancy network. Exploring the development of digital finance in the urban agglomeration of the Pearl River Delta (PRD), which is the bellwether of China's economy, can provide important practical experience for the economic construction of coastal areas and even the whole country. In this study, using the urban digital finance index issued by the Guangzhou Institute of International Finance, we measured the intensity and direction of the spatial relevancy of digital finance in the PRD urban agglomeration by applying the gravity model, modified in the calculation of distance between cities. Then, we examined the influencing factors of the spatial network of digital finance through the quadratic assignment procedure (QAP) approach. The achieved results are as follows. First, although the overall density is low, the network is tightly connected and stable. Second, in terms of individual characteristics of the network, Guangzhou, Shenzhen, Foshan still play the leading roles in the spatial network of digital finance. Third, the digital finance network does not have bidirectional spillover block. The links between segments are relatively loose. Fourth, economic level, degree of opening up, Internet level and geographical location are important factors in driving the formation of spatial relevancy of digital finance in the PRD urban agglomeration.
After signing the Paris Agreement and piloting carbon trading for many years, China has taken a significant step toward carbon neutrality. Carbon price forecasting is helpful to construct an ...effective and stable carbon pricing mechanism and provide practical guidance for production, operation, and investment. This paper builds multiple one-step-ahead predictors to analyze and forecast carbon prices, based on Complete Ensemble Empirical Mode Decomposition with Adaptive Noise (CEEMDAN) and Long Short-Term Memory (LSTM) recurrent neural network, with the close prices of Guangzhou Emission Trading Scheme (Guangzhou ETS) from March 14, 2014, to August 31, 2021. After an initial period of unreasonable pricing and market adapting, the carbon price of the Guangzhou ETS began to recover gradually. According to previous literature, this paper summarizes two fundamental CEEMDAN–LSTM frameworks and proposes a hybrid one combined with Variational Modal Decomposition (VMD). With the help of adaptive reducing learning rate Adam optimizer and the early stop mechanism, the forecast turns out stable and reliable results, with a best average coefficient of determination (R2) of 0.982 and Mean Absolute Percentage Error (MAPE) of 0.555%, which shows that Sample Entropy integration and re-decomposition methods are conducive to carbon price forecasting. Validations of four ETS and different timesteps also verify the effectiveness of the hybrid VMD LSTM method, but it still needs to be optimized for practice.
•Summarize two fundamental frameworks based on CEEMDAN and LTSM.•Test and improve by the average performance of multiple runs.•Compare re-decomposition methods and prove the effectiveness of VMD.•Propose a reliable and stable hybrid framework for carbon price forecasting.•Reproduce easily due to the upload files in supplementary and Github.
This study aims to achieve intelligent decision making in HVDC systems in the framework of knowledge graphs (KGs). First, the whole life cycle KG of an HVDC system was established by combining ...intelligent decision making. Then, fault diagnosis was studied as a typical case study, and an intelligent decision-making method for HVDC systems based on XGBoost that significantly improved the speed, accuracy, and robustness of fault diagnosis was designed. It is noteworthy that the dataset used in this study was extracted in the framework of KGs, and the intelligent decision making of KG and HVDC systems was accordingly combined. Four kinds of fault data extracted from KGs were firstly preprocessed, and their features were simultaneously trained. Then, sensitive weights were set, and the pre-computed sample weights were put into the XGBoost model for training. Finally, the trained test set was substituted into the XGBoost classification model after training to obtain the classification results, and the recognition accuracy was calculated by means of a comparison with the standard labels. To further verify the effectiveness of the proposed method, back propagation (BP) neural network, probabilistic neural network (PNN), and classification tree were adopted for validation on the same fault dataset. The experimental results show that the XGBoost used in this paper could achieve accuracy of over 87% in multiple groups of tests, with recognition accuracy and robustness being higher than those of its competitors. Therefore, the method proposed in this paper can effectively identify and diagnose faults in HVDC systems under different operation conditions.
Since 2018, China has implemented the Environmental Protection Tax as a market-based envi-ronmental regulation tool to encourage enterprises, especially heavy-polluting ones, to reduce emissions and ...engage in green innovation. The effectiveness of this policy in promoting green innovation has become a focal point of attention for Chinese society, as it directly relates to the coordinated high-quality development of the economy and environmental protection, as well as the achievement of China’s “carbon peaking and carbon neutrality goals”. This study evaluates the green innovation effect of the Environmental Protection Tax policy on heavy-polluting enterprises in China using micro-data of listed enterprises from 2003 to 2019, based on the new market-oriented environmental regulation tool. We employ the propensity score matching and differ-ence-in-differences method (PSM-DID) to follow up on the green innovation effect of China’s Environmental Protection Tax policy and reveal its implementation effect. Empirical results indicate that, first, the Environ-mental Protection Tax policy contributes to heavy-polluting enterprises’ R&D innovation of green patents, and this conclusion holds through various robustness tests. Second, the policy’s impact on green innovation types of heavy-polluting enterprises exhibits heterogeneity, with a more significant positive effect on the utility model patent than on the invention patent. Third, the green innovation effect of the policy differs ac-cording to regional economic development and enterprise ownership attributes. Finally, financing constraints do not significantly affect the green innovation of heavy-polluting enterprises. These enterprises remain pro-active in green innovation, even under high financing constraints. To further promote green innovation of heavy-polluting enterprises and achieve China’s dual carbon goals, the government should continue to imple-ment and improve the Environmental Protection Tax policy, leveraging its positive effect on green innovation.
A 2 × 2 wideband circularly polarized (CP) antenna array operating at millimeter wave (mmWave) band is presented. The array element is a wideband CP Archimedean spiral radiator with special-shaped ...ring slot. The elements are fed by an unequal amplitude (UA) feeding network based on a microstrip line (MSL) power divider. The side lobe level is improved by this UA feeding network. In addition, a cross slot is employed to isolate the elements for decoupling. A prototype is fabricated, and the measured results show that the proposed array achieves an impedance bandwidth (IBW) of 6.31 GHz (22.5% referring to 28 GHz) and an axial ratio bandwidth (ARBW) of 7.32 GHz (26.1% referring to 28 GHz). The peak gain of the proposed array is 11.3 dBic, and the gain is greater than 9.3 dBic within the whole desired band (from 25 GHz to 31 GHz). The proposed array consists of only one substrate layer and can be built by the conventional printed circuit board technology. Attributed to the characteristics of wide bandwidth, simple structure, low profile, and low cost, the proposed antenna array has a great potential in mmWave wireless communications.
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