  In a recent paper Tettamanzi et al (2009 Nanotechnology \bf{20} 465302)
describe the fabrication of superconducting Nb nanowires using a focused ion
beam. They interpret their conductivity data in the framework of thermal and
quantum phase slips below $T_c$. In the following we will argue that their
analysis is inappropriate and incomplete, leading to contradictory results.
Instead, we propose an interpretation of the data within a SN proximity model.
