  Existing data on the (unpolarised) transverse structure function of the
proton are analyzed for large values of the Bjorken variable x. The
leading-twist and a phenomenological higher-twist contributions are
simultaneously determined from a power correction analysis of the Nachtmann
moments for values of the squared four-momentum transfer between ~ 1 and 20
(GeV/c)**2. The results obtained adopting the next-to-leading order
approximation and those including the effects of soft gluon resummation are
compared. The sensitivity of the extraction of large-x higher twists to
high-order radiative corrections as well as to the value of alphas(MZ) is
illustrated.
