Supplement 1. R code for performing nonlinear regression, with data (embedded in the R code), and a short description of the program.

<h2>File List</h2><blockquote> <p><a href="nonlinear_regression.R">nonlinear_regression.R</a></p> </blockquote><h2>Description</h2><blockquote> <p>The "nonlinear_regression.R" program provides a short example (with data) of one way to perform nonlinear regression in R (version 2.8.1). This example is not meant to provide extensive information on or training in programming in R, but rather is meant to serve as a starting point for performing nonlinear regression in R.</p> <p>R is a free statistical computing and graphics program that may be run on of UNIX platforms, Windows and MacOS. R may be downloaded here: http://www.r-project.org/.<br> <br> There are several good resources for learning how to program and perform extensive statistical analyses in R, including:<br> <br> Benjamin M. Bolker. Ecological Models and Data in R. Princeton University Press, 2008. ISBN 978-0-691-12522-0. [ http://www.zoology.ufl.edu/bolker/emdbook/ ]<br> <br> Other references are provided at http://www.r-project.org/ under “Documentation” and “Books”. </p>