About the Authors

Noriyuki Kushida

noriyuki.kushida@ctbto.org

Affiliation International Data Centre, the Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization, Vienna, Austria

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Performed the experiments: NK. Analyzed the data: NK. Contributed reagents/materials/analysis tools: NK. Wrote the paper: NK.