Roberto Hernández Ramírez Mexicana de Valores, S.A. de C.V. (Mexican Stock Exchange) - 1974 to 1979, Director - 1972 to 2003; Member of the International Advisory Committee of the Federal Reserve Bank of New York - 2002 to present; Chairman, Asociacion Mexicana de Bancos (Mexican Bankers Association) - 1993 to 1994; Member, Bolsa Mexicana de Valores, S.A. de C.V. - 1967 to 1986; Director of Citigroup since from 2001 to 2009; Other Directorships: GRUMA, S.A. de C.V. and Grupo Televisa, S.A.; Hernández Ramirez received a bachelor's degree in business administration from the Ibero-American University (1964), co-founded "Acciones y Valores de México (Accival)" in
Dioscorea mexicana caudex, bear heart-shaped leaves. "Dioscorea mexicana" ranges from the state of San Luis Potosí in northeastern Mexico south to Panama. It is notable for its production of diosgenin, which is a precursor for the synthesis of hormones such as progesterone. Russell Marker developed the extraction and manufacture of hormones from "D. mexicana" at Syntex. Later the Mexican barbasco trade focused instead on "Dioscorea composita" instead, as this variety has a higher diosgenin content. Dioscorea mexicana Dioscorea mexicana, Mexican yam or cabeza de negro is a species of yam in the genus "Dioscorea". "Dioscorea mexicana" is a caudiciform dioscorea having either