1 College of Health Professions and Biomedical Sciences, The University of Montana, Missoula, MT 59812, USA; Escuela de Ciencias de la Salud, Universidad del Valle de México, 04850 México. Electronic address: lilian.calderon-garciduenas@umontana.edu.
2 Historian and Economist, Private Consultant, Mexico City, 04310, Mexico.