  In reaction rate theory, in input-output type models and in
reaction-diffusion problems when the total derivatives are replaced by
fractional derivatives the solutions are obtained in terms of Mittag-Leffler
functions and their generalizations. When fractional calculus enters into the
picture the solutions of these problems, usually available in terms of
hypergeometric functions, G and H-functions, switch to Mittag-Leffler functions
and their generalizations into Wright functions. In this paper, connections are
established among generalized Mittag-Leffler functions, pathway model, Tsallis
statistics, superstatisitcs and power law, and among the corresponding entropic
measures.
