In order to reveal the mechanism of succession in subtropical forest along a light gradient, we investigated photosynthetic physiological responses to three light environments in five tree species including a pioneer species Pinus massoniana Lamb., two mid-successional species Schima superba Gardn. et Champ. and Castanopsis fissa (Champ. ex Benth.) Rehd. et Wils., and two late-successional species Cryptocarya concinna Hance. and Acmena acuminatissima (BI.) Merr et Perry) that were selected from Dinghu Mountain subtropical forest, South China. Results showed that, among the three kinds of species in all light conditions (100%, 30% and 12% of full sunlight), the pioneer species had the highest photosynthetic capacity (Amax), light saturation point (LSP), carboxylation efficiency (CE) and maximum utilisation rate of triose phosphate (TPU) that characterised a strong photosynthetic capacity and high carbon dioxide uptake efficiency. However, a higher light compensation point (LCP) and dark respiration (Rd) as well as lower apparent quantum yield (AQY) indicated that the pioneer specie cannot adapt to low light conditions. Mid-successional species had photosynthetic characteristics in between pioneer and late-successional species, but had the greatest effective quantum yield of PSII (ΦPSII) and light use efficiency (LUE, expressed in terms of photosynthesis). In contrast to pioneer and mid-successional species, late-successional species had lower photosynthetic capacity and carbon uptake efficiency, but higher shade tolerance and high-light heat dissipation capacity, as characterised by higher levels of total xanthophyll cycle pigments (VAZ) and de-epoxidation state of xanthophyll cycle (DEPs). These results indicate that photosynthetic capacity decreases along the successional axis and that late-successional species have more responsive heat dissipation capability to compensate for their inferior photosynthetic capacity.

Self-esteem has always been a hot research object in the field of adolescent mental health. But in longitudinal research, using a single slope to describe the trajectory of adolescent self-esteem is unrealistic. The piecewise growth mixture model (PGMM) was used to fit the data in this study. Selecting from China Family Panel Studies database, a total of 1,759 individuals were selected and their self-esteem (RSES) scores over the years were used as the tracking index. Based on the characteristics of the development trajectories of three latent classes, class 1 was referred to as “stable low level group,” class 2 was named “rapidly rising group,” and class 3 was referred to as “rapidly decrease group.” And there were two stages in the development process of self-esteem in the adolescent group. The slope of the stable low level group showed a significant downward trend in the first stage and a significant upward trend in the second stage, with a relatively flat development trajectory and relatively low self-esteem on the whole. The slope of the rapidly rising group showed an insignificant upward trend in the first stage and a significant rapid upward trend in the second stage. The rapidly decrease group showed a significant and rapid downward trend in the first stage and a significant and rapid upward trend in the second stage. In the development of self-esteem in adolescence, there were three latent classes in which the characteristics of development trajectories were different. Age of 14 is the turning point between the two stages of development.

Characteristic development is a process of intentionally solidifying and cultivating something's uniqueness. This article analyzes the uniqueness of university library cultural services in comparison with those provided by other service institutions. Furthermore, this article reveals the differences between cultural services and other types of library services. Based on these analyses, this constructive research finds a way to achieve cultural services' characteristic development by taking service factors as the breakthrough point. The main strategies include building a professional service team, focusing on user demands, constructing characteristic resources, optimizing service spaces and facilities, and upgrading service brands; all of these strategies should be developed round the issue of culture. Finally, corresponding to the above strategies, this paper article the measures and effects of Wuhan University Library cultural services to share their experience.