As the product of natural process, land is an essential but nonrenewable resource for humankind. Urban land use efficiency directly reflects the coupling between urban systems and land use systems. It also serves as the key indicator for measuring land productivity and regional development quality. In this study, the land use efficiency of 65 county-level cities in the Yellow River Basin has been measured by applying the Data Envelope Analysis (DEA) and Spatial Autocorrelation Analysis methods. It makes up for the deficiency and defect of the existing research. The result indicates that in 2000~2018, the overall urban land use efficiency in 65 prefecture-level cities is unbalanced, with significant gaps between cities with high efficiency and low efficiency. In 2000~2018, the average urban land use efficiency in these 65 cities shows a tendency of declining. In 2000~2018, the spatial distribution of land use efficiency of these 65 cities indicates significant positive correlation, featured by the clustering of regions with high (low) efficiency. In terms of the spatial distribution of urban land use efficiency in the Yellow River Basin, it is marked by apparent spatial clustering. Specifically, from east to west, from coastal areas to inland regions, from downstream to upstream, the urban land use efficiency differs from high value areas to low value areas. On the whole, it is featured by high value in the east and low value in the west, while declining from downstream to upstream.

Due to the rapid urbanization of the Yangtze River Delta in China, large numbers of formerly rural residents have migrated to the cities. To adjust the structure of rural land use, the government has performed extensive land consolidation. Previous studies indicated that the land consolidation has affected farmland quality to some extent. However, the effect of the land consolidation on farmland heavy metal concentrations has rarely been reported. In this study, the Jintan District was used as an example, and 40 sampling sites of various consolidation types in 4 representative areas of rural land consolidation were selected. Soil samples were collected from these sites, and the heavy metal concentrations were analyzed. We used multivariate methods of correlation analysis and principal component analysis to study the conditions and sources of the heavy metal contamination in the soil. The results indicate that the mean concentrations of Cd, Hg, Ni, Cu, and Zn in the soil all exceeded the background values. The mean concentration of Cd was 0.409 mg/kg, and the enrichment factor (EF) was 4.54, making Cd the most prevalent heavy metal soil contaminant in the study area. The enrichment of soil heavy metals varied among the various representative areas. Suburban areas surrounding the central cities were mainly enriched in Hg, with an EF of 6.20. The comprehensive development zone displayed enrichment in Cd, with an EF of 7.79. The heavy metal concentrations in the soil also differed depending on the type of land consolidation. The reclaimed soil of rural settlements contained high levels of Cd and Zn, with EFs of 7.25 and 2.52, respectively, which were related to the land use before the land consolidation. The soil heavy metals of the study area were affected by both human activity and natural background contamination.

Science and technology are the primary productive forces of a country. However, in today's STEM (Science, Technology, Engineering, and Mathematics) fields, gender segregation remains an issue. Half of the world's population is female, yet women face considerable barriers and are underrepresented in STEM education and occupations. This article mainly focuses on STEM education, to explore how gender role is shaped and reinforced in high school and how it leads to gender segregation of STEM majors in Chinese universities. The findings show that gender stereotype leads female students to devalue self-cognition and self-assessment and, as a result, they often underestimate their ability in STEM disciplines. Second, the educational policy in high school causes female students to prioritize liberal art subjects at the expense of natural science subjects. Third, high school curriculum, textbooks, and other teaching materials that contain gender bias and unhealthy teacher-student interactions reinforce the stereotype of gender role. Fourth, the decisions of majors are strongly affected by traditional Chinese culture that represents the preferences and career expectations for different genders. At the end of this article, implications will be provided.

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