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To study patterns of volcanicity it is important to use historical data. These data are, however, frequently incomplete. We develop a nonparametric procedure for estimating second-order parameters of the point process of eruption starts from a catalog. This method requires an assumption of underlying stationarity, of smoothness of the probability of recording an eruption as a function of time, and of independence of this probability from the history of the process. We illustrate the procedure on the Smithsonian catalog of worldwide volcanic eruptions. We also look separately at data from Japan and Iceland. The global and the Japanese data sets show little structure, but the Icelandic data exhibits a tendency toward periodic behavior, with a period of about 40 years. We do not see any regularity corresponding to certain long tidal cycles, as has previously been suggested in the literature. [ABSTRACT FROM AUTHOR]

This paper describes the methods of the Wave 1 (2018) International Tobacco Control (ITC) Japan Survey. The respondents were adults aged 20 years and older in one of four user groups: (1) cigarette-only smokers who smoked at least monthly and used heated tobacco products (HTPs) not at all or less than weekly, (2) HTP-only users who used HTPs at least weekly and smoked cigarettes not at all or less than monthly, (3) cigarette-HTP dual users who smoked at least monthly and used HTPs at least weekly, and (4) non-users who had never smoked or who smoked less than monthly and used HTPs less than weekly. Eligible respondents were recruited by a commercial survey firm from its online panel. Respondents were allocated proportionally to sample strata based on demographic, geographic, and user type specifications benchmarked to a national reference. Survey weights, accounting for smoking/HTP use status, sex, age, education, and geography, were calibrated to benchmarks from a nationally representative survey in Japan. Response rate was 45.1% and cooperation rate was 96.3%. The total sample size was 4615 (3288 cigarette smokers, 164 exclusive HTP users, 549 cigarette-HTP dual users, and 614 non-users). The 2018 ITC Japan Survey sampling design and survey data collection methods will allow analyses to examine prospectively the use of cigarettes and HTPs in Japan and factors associated with the use of both products and of transitions between them.

In Japan, the tobacco industry promotes heated tobacco products (HTPs) as a reduced-risk tobacco product. This study examines: (1) smokers' harm perceptions of HTPs relative to combustible cigarettes; (2) differences in relative harm perceptions between exclusive smokers and smokers who use HTPs (concurrent users) and between concurrent users based on frequency of product use; and (3) if smokers who were exposed to HTP advertising hold beliefs that are consistent with marketing messages of lower harmfulness. This cross-sectional study included 2614 adult exclusive cigarette smokers and 986 concurrent users who reported their perceptions of harmfulness of HTPs compared to cigarettes, as well as their exposure to HTP advertising in the last six months. Among all smokers, 47.5% perceive that HTPs are less harmful than cigarettes, 24.6% perceive HTPs to be equally as harmful, 1.8% perceive HTPs as more harmful, and 26.1% did not know. Concurrent users are more likely than exclusive smokers to believe that HTPs are less harmful (62.1% versus 43.8%, p < 0.0001) and less likely to report that they did not know (14.3% versus 29.4%, p < 0.0001). Frequent HTP users are more likely than infrequent users to believe that HTPs are less harmful (71.7% versus 57.1%, p ≤ 0.001). Believing that HTPs are less harmful than cigarettes was associated with noticing HTP advertising on TV ( p = 0.0005), in newspapers/magazines ( p = 0.0001), on posters/billboards ( p < 0.0001), in stores where tobacco ( p < 0.0001) or where HTPs ( p < 0.0001) are sold, on social media ( p < 0.0001), or in bars/pubs ( p = 0.04). HTP users were significantly more likely than non-HTP users to believe that HTPs are less harmful than cigarettes, with this belief being more prominent among frequent users. Smokers who have been exposed to HTP advertising were more likely to perceive HTPs as less harmful than cigarettes.