Funding for this research was provided by:
Simons Foundation (ID0ESKAC80)
Text and Data Mining valid from 2018-06-22
Received: 7 February 2018
Accepted: 2 May 2018
First Online: 22 June 2018
: The authors declare that they have no competing interests.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.