Perhaps of more interest to Charlie's younger audience (and older, 
too!):

Brooks, J.R., N. Buchmann, S. Phillips, B. Ehleringer, R. Evans, L.A. 
Martinelli, W.T. Pockman, D. Sandquist, J.P. Sparks, L. Sperry, D.G. 
Williams, and J.R. Ehleringer. 2002. Heavy and light beer: a carbon 
isotope approach to detecting C4 carbon in beers of different origins, 
styles and prices. Journal of Agricultural & Food Chemistry 
50:6413-6418.

A pdf can be obtained here: http://www.uwyo.edu/dgw/Publications.html

Cheers,
Nathan English

On Jan 22, 2009, at 4:58 PM, Marilyn Fogel wrote:

> Dear Folks,
>
> I received this message from a colleague who is teaching students 
> about the influence of corn. Do any of you alert readers have a 
> reference at your fingertips that you could recommend for Charlie?
>
> "Next Tuesday Washington College is hosting a viewing of the movie 
> "King
> Corn," which is a critique of the use of corn products in our country 
> (see
> description below).
>
> One of the most fascinating things I heard about this issue was in one 
> of
> your talks: The stable isotope evidence that Europeans coming to the US
> experience a shift in their carbon isotope ratios in response to the
> corn-heavy diet.  Does that data appear in publication anywhere? I 
> would
> love to bring that up at the viewing of this movie during the 
> discussion
> period."
>
> Marilyn Fogel
>
>
> Dr. Marilyn L. Fogel
> Geophysical Laboratory
> Carnegie Institution of Washington
> 5251 Broad Branch Rd., NW
> Washington, DC 20015
> Phone (202) 478-8981
> Main office (202) 478-8900
> FAX (202) 478-8901
> Website: http://fogel.gl.ciw.edu/
>