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The Qinghai–Tibet Plateau is the highest and largest permafrost area in the middle and low latitudes of China. In this region, permafrost thaw settlement is the main form of expressway subgrade disaster. Therefore, the quantitative analysis and regionalization study of permafrost thaw settlement deformation are of great significance for expressway construction and maintenance in the Qinghai–Tibet region. This paper establishes a thaw settlement prediction model using the thaw settlement coefficient and thaw depth. The thaw depth was predicted by the mean annual ground temperatures and active-layer thicknesses using the Radial Basis Function (RBF) neural network model, and the thaw settlement coefficient was determined according to the type of ice content. Further, the distribution characteristics of thaw settlement risk of the permafrost subgrade in the study region were mapped and analyzed. The results showed that the thaw settlement risk was able to be divided into four risk levels, namely significant risk, high risk, medium risk and low risk levels, with the areas of these four risk levels covering 3868.67 km2, 1594.21 km2, 2456.10 km2 and 558.78 km2, respectively, of the total study region. The significant risk level had the highest proportion among all the risk levels and was mainly distributed across the Chumar River Basin, Beiluhe River Basin and Gaerqu River Basin regions. Moreover, ice content was found to be the main factor affecting thaw settlement, with thaw settlement found to increase as the ice content increased. [ABSTRACT FROM AUTHOR]

Soil proteinase and proteinase-producing microbial community are closely associated with soil fertility and soil health. Sea rice has been planted in the coastal beach of Jiaozhou Bay, China, in an effort to transform saline-alkali soil into arable land. However, the knowledge regarding the bacterial degradation of organic nitrogen in sea rice soils is limited. This study aims to investigate the physicochemical characteristics and enzymatic activities of the sea rice soils, as well as the microbial communities by both the Illumina sequencing-based culture-independent technology and culture-dependent methods. Sea rice soils exhibited a lower salinity and higher organic matter content and proteinase activity, as well as an increase in both the richness and diversity of the proteinase-producing bacterial community, compared to the adjacent non-rice soils. The Proteobacteria phylum and the Gammaproteobacteria class were dominant in sea rice soils, showing higher abundance than in the reference soils. The Planococcus genus and Bacillus-like bacterial communities were abundant in the cultivable proteinase-producing bacteria isolated from sea rice soils. Furthermore, a significant proportion of the extracellular proteinase produced by the isolated soil bacteria consisted of serine proteinases and metalloproteinases. These findings provided new insights into the degradation of soil organic nitrogen in coastal agricultural regions. [ABSTRACT FROM AUTHOR]

The outbreak of the COVID-19 pandemic has caused negative impacts on people's lifestyles, as well as considerable indirect social impacts, which has even overshadowed the direct impact of virus infection itself. This study is aimed at examining the changes in physical health-related indexes of Chinese college students before and after the COVID-19 lockdown. The data of this study are from the National Physical Health Testing Program, covering 43 college students (male: 22) from a class of a Chinese university. Paired t -tests were performed on the physical health test data separately collected in November 2019 before the COVID-19 pandemic and October 2020 after the COVID-19 lockdown was lifted. As shown by the test results, compared to the prelockdown data, college students had an increased body mass index (BMI) (0.43 (SD 0.94) P = 0.004), decreased vital capacity (VC) (-128.98 (SD 310.13) ml P = 0.009), and lowered performance in the 800/1000 m endurance (-6.21 (SD 8.81) points P < 0.001) and standing long jump tests (-2.44 (SD 7.37) points P = 0.036) after the lockdown, and the differences in these regards all were significant. In addition, for the students in the overweight/obese group, their pre- and postlockdown physical fitness test results were found to have no statistically significant difference (P > 0.05), but the students in the control group showed a significantly increased BMI, as well as significantly decreased vital capacity and performance in the 800/1000 m endurance and standing long jump tests (P < 0.05). The findings of this study are expected to help government departments and policymakers better understand the impacts of school closures and online learning on the physical health of adolescents, while providing a basis for the formulation of measures that are aimed at reversing adolescents' physical health decline. [ABSTRACT FROM AUTHOR]

This study presented a narrative review of the six latest sets of guidelines on physical activity for children and adolescents from Australia, Canada, China, the United Kingdom, the United States and WHO, and analysed the history of the development of the guidelines; the policy context in which the guidelines were developed; and the main subjects of the guidelines. The core elements of the latest guidelines were identified and compared, including frequency, intensity, duration (time), and type of physical activity, assessment intensity of physical activity, and risk prevention for physical activity participation. There is an urgent need for obtaining the latest scientific evidence to support and update the contents of the Chinese guidelines. We therefore make the following recommendations for future revisions of the Chinese guidelines based on the findings of this study: (1) to update the recommended frequency, intensity, duration, and type of physical activities that meet the needs for Chinese children and adolescents; (2) to update the methods for assessing physical activity intensity, and identifying and managing the risk factors in participating in physical activity; and (3) to incorporate analyses and reviews of school physical education curriculum for effectively achieving the adequate levels of physical activity., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Hu, Zhou, Crowley-McHattan and Liu.)