Funding for this research was provided by:
Bundesministerium für Bildung und Forschung (01EC1007A)
Received: 1 July 2020
Accepted: 12 May 2021
First Online: 12 June 2021
: The study was conducted in accordance with the declaration of Helsinki and approved by the ethics committee of the University of Tübingen (ref: 113/2011BO2). All participants provided written informed consent.
: Not applicable.
: The authors declare that they have no competing interests.