  Recently it has been observed that the conductance fluctuations of atomic
size gold contacts are suppressed when the conductance is equal to an integer
multiple of the conductance quantum. The fact that these contacts tend to
consist exclusively of fully open or closed modes has been argued to be the
origin for this suppression. Here, the experiments have been extended to a wide
range of metallic elements with different chemical valence and they provide new
information about the relation between the mode composition and statistically
preferred conductance values observed in conductance histograms.
