Figure 2

Cosine similarity distribution of authors’ interest who started their careers (published their first paper) in 1980. (panel (A)) We compare authors’ interest vectors between the first and last year of publication. Interest vectors \(\mathbf{x}^{i,S}\) were built using the second level of the classification scheme with 68 PACS. (panel (B)) Comparison between real data (pink bars) and a null model (green bars) where, for each author, an interest vector is constructed selecting, instead of the last year of publication, one year at random from the authors career. Average values and error bars are the results of 10³ bootstraps. (panel (C)) same comparison of panel (B) but the distance between vectors has been measured using the Jaccard index instead of the Cosine Similarity