Funding for this research was provided by:
Fondo Nacional de Desarrollo Científico y Tecnológico (1010572, 1100414)
Comisión Nacional de Investigación Científica y Tecnológica (21110244)
Received: 12 November 2017
Accepted: 19 February 2018
First Online: 27 February 2018
Ethics approval and consent to participate
: This study was approved by the Ethics Committee at the University of Chile which abides by the Declaration of Helsinki principles. Participation was voluntary and all individuals signed an informed consent form to participate.
: Not applicable.
: The authors declare that they have no competing interests.
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