Funding for this research was provided by:
Received: 16 December 2015
Accepted: 28 January 2018
First Online: 6 February 2018
Ethics approval and consent to participate
: The study was performed according to the principles of the Declaration of Helsinki.The study protocol was approved by the Office of the Committee for Research Ethics (Social Sciences), Faculty of Social Sciences and Humanities, Mahidol University (COA. No.: 2014/328.2511). Written informed consent was obtained from all participants.
: 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.