Using data from a survey on the use of online social tools by mid-aged and older adults in 2021, this paper investigates the relationships between the variety, relationship types, and activity level of online communities, and social networks of mid-aged and older adults by using the structural equation modeling. The study found that the mid-aged and older adults had better relationships with their relatives and friends as the variety of online communities increased. Strong and sub-strong tie groups could promote family and friend networks, respectively, while sub-weak and weak tie groups could promote both types of networks. Moreover, the higher the activity in the online communities, the greater the promotion of their friend networks. Findings promote the understanding of changes in the social network in the internet era. Online communities break through the physical distance in the traditional differential mode of associations by enhancing family relations, strengthening and expanding friend relations horizontally, and helping restore interrupted friend relations vertically. The breadth and depth of the social network of mid-aged and older adults have been developed through online communities.

This study uses data from the 2018 China Longitudinal Ageing Social Survey to explore patterns of older adults' social engagement by latent class analysis. Based on their participation in personal life domain (i.e. learning and communication, personal recreation, working, and volunteering) and family life domain (i.e. caring for parents, caring for grandchildren, and caring for children), four patterns are discovered, including Personal-Family Balanced Activity (P-F), PersonalCentered Activity (P-C), Family-Centered Activity (F-C), and Low Activity. Linear regression analysis reveals that Low Activity are associated with the lowest social adaptation, followed by F-C Activity, while P-C and P-F Activity achieved the best scores and showed no statistical difference. Moreover, urban-rural differences are found in the relationships between social participation patterns and social adaptation. The results suggest that we should protect the social participation rights of older adults, enrich the ways and contents of social participation, and balance their personal life with family life to enhance their abilities to adapt to the social development and changes.

 Using the 2010 population census data of Chongqing,China,the paper examines the relationship between population migration and children??s education. Particularly this paper compares three types of rural children,the left-behind children,the children with parents at home,and the children migrating to cities,regarding to their enrollment rate,completion rate of a certain level of schooling,and the chance of progressing to the next level of education. Taking advantage of a large sample and a more accurate definition of children??s type,the paper provides a better understanding of the relations between population migration and children??s education. The left-behind children have the highest rates of enrollment and progression,whereas the migrant children have the lowest rates for these two indicators and the children with parents at home have the middle rates. In regard to the completion of junior middle school,the three types of children have a reverse order. The differences of children??s education vary by children??s gender,their parental education,and the economic development of their home regions. Income,parent-child separation,and the interference of urban institution could be reasons for educational differences among the three types of children.