We have continued working on transport in disordered media, in particular concentrating on the theory of comb models. These have a simple mathematical structure but reproduce many features observed in experiments. A second study undertaken in the past year is that of the effects of constraints on random walks. These are being studied in the context of polymer chains whose ends are pinned. We have developed a theory of first passage times for a significant class of non-Markovian processes in the presence of absorbing barriers. Together with Dr. Szabo we are writing either a long review or a short book on the theory of reaction rates in chemical physics.
