Contribution to authorship
Juanzi Shi conceived the study question. He Cai and Juanzi Shi were responsible for the design of the study. He Cai and Na Li undertook the statistical analyses. Stephan Gordts, Tao Wang, and Hui Wang developed the first draft of the article, and all author contributed to the interpretation of findings and revising of drafts of the article. All authors approved the final article for publication.