Geoarchaeological Evidence of Middle-Age Tsunamis at Stromboli and Consequences for the Tsunami Hazard in the Southern Tyrrhenian Sea.

Large-scale landslides at volcanic islands are one of the most dangerous geological phenomena, able to generate tsunamis whose effects can propagate far from the source. However, related deposits are scarcely preserved on-land in the geologic records, and are often difficult to be interpreted. Here we show the discovery of three unprecedented well-preserved tsunami deposits related to repeated flank collapses of the volcanic island of Stromboli (Southern Italy) occurred during the Late Middle Ages. Based on carbon datings, on stratigraphic, volcanological and archaeological evidence, we link the oldest, highest-magnitude investigated tsunami to the following rapid abandonment of the island which was inhabited at that time, contrary than previously thought. The destructive power of this event is also possibly related to a huge marine storm that devastated the ports of Naples in 1343 (200 km north of Stromboli) described by the famous writer Petrarch. The portrayed devastation can be potentially attributed to the arrival of multiple tsunami waves generated by a major landslide in Stromboli island, confirming the hypothetical hazard of these phenomena at a regional scale.

Comparison of systemic flurithromycin therapy and clinical procedures in the treatment of periodontal diseases.

The purpose of the present investigation was to evaluate, in 20 periodontal patients, the microbial and clinical effects of flurithromycin therapy plus scaling and root planning (SRP) in comparison with SRP alone. Clinical assessments of plaque, bleeding on probing and pocket depth were made prior to SRP alone and SRP plus flurithromycin therapy (375 mg twice daily for 5 days) and after both treatments. Subgingival plaque samples (n. 180) were taken prior to and after both treatments and analyzed by conventional bacteriological procedures. Differences in pocket depth and prevalence of bacterial species were analyzed pre- and post-therapies using statistical analyses. A significant decrease (p<0.001) was seen for pocket depth post SRP alone and post SRP plus flurithromycin. After two treatments, Actinobacillus actinomycetemcomitans, Bacteroides forsythus and Prevotella melaninogenica were eradicated from all tested sites. If we compare the prevalence of the species isolated after SRP alone and after SRP plus flurithromycin statistically significant differences were detected for P. gingivalis and for Fusobacterium nucleatum (p<0.05 and p<0.01, respectively). Flurithromycin can be considered a useful adjunct to mechanical periodontal treatment since it is more efficient in eliminating periodontal pathogens.