We calculate nuclear enhanced power corrections to structure functions
measured in deeply inelastic lepton-nucleus scattering in Quantum
Chromodynamics (QCD). We find that the nuclear medium enhanced power
corrections at order of O(αs/Q2) enhance the longitudinal structure
function FL, and suppress the transverse structure function F1. We
demonstrate that strong nuclear effects in σA/σD and RA/RD,
recently observed by HERMES Collaboration, can be explained in terms of the
nuclear enhanced power corrections.Comment: Latex, 10 pages including 3 figure