Differences in scientific findings usually point to the necessity for a more nuanced theory, and this case is no exception. More recent papers have found more and more characteristics on which granular segregation hinges. For example, a recent study by Ulrich et al. found that a transition from reverse Brazil nut effect to Brazil nut effect could be induced simply by waiting long enough. That is, they found that after 25 hours of continuous shaking, or aging, a sharp transition occurred for unchanged driving conditions. Perhaps more telling was their find that after an aggressive cleaning procedure of the glass tube in which the beads were, the system returned to its original position.