Fig. 5

Topic network highlighting four topic communities A to D that emerge from Louvain network clustering; network generated by limiting to top 10 topics per document and setting minimum threshold for co-occurrence to the 50% quantile (see section “Methods for topic model analysis” for details); plotting parameters: (i) line width of connections proportional to co-occurrence, (ii) plot limited to the top 1.5% strongest connections, (iii) topics with strongest positive trends (see Table 1) in bold letters, (iv) graph shows two link types, connections are plotted in dark grey when both topics of a pair have a strong positive trend; connections are plotted in light grey if only one of the topics has a strong positive trend, (v) vertex size proportional to betweenness centrality, (vi) top 5% vertices regarding betweenness centrality (see subsection “Topic network and topic communities” under the “Results” section) marked in grey