Funding for this research was provided by:
National Research Foundation (443920 HUB 1138)
Deutscher Akademischer Austauschdienst
Received: 4 April 2018
Accepted: 13 May 2018
First Online: 10 July 2018
Ethics approval and consent to participate
: The study was approved by the Human Research Ethics Committee of the University of Cape Town (reference number 092/2016). All participants signed appropriate informed consent forms and the study was performed in accordance with the standards of ethics outlined in the Declaration of Helsinki.
: Not applicable
: Andreas Venhorst, Dominic P. Micklewright, and Timothy D. Noakes declare that they have no competing interests.
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