A transport barrier is introduced in the one-dimensional sandpile model by
reducing the local flux in a barrier region. This reduction causes a modifi
cation in the structure of the avalanches and triggers quasiperiodic fluctu
ations of the particle fluxes. The frequency of these fluctuations is inver
sely proportional to the transport barrier width. (C) 2001 American Institu
te of Physics.