  Diffusive shock acceleration theory suggests that the ``universal'' energy
spectrum of electrons with a power-law index p approximately equal to 2.3,
commonly used to model GRB afterglows, cannot extend below an electron lorentz
factor gamma_e equal to the bulk lorentz factor of the blast wave multiplied by
the ratio of proton and electron masses. We suggest that the electron energy
distribution has a slope p < 2 below this limit, down to an appropriate
gamma_m. A two-slope spectrum such as this provides a good model for the
afterglow of GRB010222.
