Keith- sorry it took a while for a response.  A power law distribution is
described by an inverse exponential function.  In regards to training and
many natural systems it relates to intensity VS time.  I am a biochemist,
not well versed in describing the complex systems power laws describe but a
couple of books which have helped me are "Chaos, fractals, and power laws",
and a new one I found "Fractals and Chaos- an illustrated course" by Paul S
Addison.  I think it was last month Ming posted a link to Steven Wolframs
interview in Frobes.  Very interesting reading.  Hope this helps!
Robb