Funding for this research was provided by:
National Science Foundation (DUE 1347817)
Text and Data Mining valid from 2019-05-16
Received: 26 October 2018
Accepted: 26 April 2019
First Online: 16 May 2019
: Not applicable.
: The authors declare that they have no competing interests.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.