Y a node lies around the shortest path in between all pairs of nodes; the moreOpen AccessFigure 1 Number of messages posted about e-cigarettes over time.quantity of shortest paths it resides in, the higher the betweenness value.23 In this context, the larger blue nodes represent discussion threads that straight hyperlink many nations collectively once they otherwise could possibly not be connected. We also calculate closeness centrality (not represented visually), which measures the distance any node would be to all other nodes. Normally, core nodes will have higher closeness, as they have shorter paths to all other nodes than these on the periphery. Together with the 2-mode network, we now possess a clear image of your pattern of interactions inside the GLOBALink forums. We have ON123300 labelled numerous nodes of interest and have identified them. Very first, we include things like the major five countries as determined by degree centrality (ie, number of discussion threads they may be present in), that are precisely the same 5 we had visually found in the country network’s core cluster. Subsequent, we label the prime 5 discussion thread IDs, as determined by their betweenness centrality:8324, six, 13 022, 6467 and 9236. These threads serve to mediate discussions amongst several pairs of countries. Last, we gather the thread IDs for the discussions which can be connected to the isolates (not labelled).Sentiment analysis Table 1 provides a common description in the sentiment scores for each of the messages. Figure 4 shows the pattern of sentiment in each message more than time. To find out how e-cigarettes compared with other topics in GLOBALink, an independent samples t test was carried out to examine the sentiment scores for the ecigarette messages against all other messages within the very same time period ( July 2005 pril 2012). There was a important distinction within the scores for e-cigarette messages (M=0.0103, SD=0.0244) and all other messages (M=0.0144, SD=0.0294); t (41 695)=-3.87, p0.001,Figure 2 GLOBALink network of country-country interactions.Chu K-H, et al. BMJ Open 2015;5:e007654. doi:ten.1136bmjopen-2015-Open AccessFigure 3 GLOBALink 2-mode network of country-thread interactions.indicating that e-cigarette postings were substantially much more damaging. A post hoc easy linear regression was performed to examine in the event the distinction in sentiment amongst ecigarettes as well as other PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/21331607 subjects may be predicted by closeness centrality. The results had been significant, F(1,32) =8.67, p0.01, and accounted for 18.86 (adjusted R2) from the explained variability. The regression equation was: predicted difference=0.029.026closeness centrality). DISCUSSION The exploratory network analysis supplied data that helped inform the later content material analysis. We can make numerous observations depending on the country-country network graph (figure 2). The network shows a core periphery structure, with quite a few nodes in a closely connected dense centre surrounded by far more loosely connected nodes at the outskirts. We can clearly see the high degree core countries, most notably the USA, Australia, Canada, Switzerland along with the UK, indicating an incredibly interactive group of nations that participated in lots of discussion threads collectively. In the other finish ofTable 1 Description of messages and sentiment Observations Raw variety of sentiment scores Mean sentiment score (SD) Imply sentiment score normalised by word count (SD) Messages with good scores Messages with adverse scores Messages neutral or unscored 853 -144 to 130 11.34584 (30.05033) 0.0103133 (0.0244054) 528 252the network, we also notice t.