  The possibility of a node in the x dependence of the Sivers and Qiu-Sterman
functions is discussed in light of its importance for the experimental check of
the overall sign change of the Sivers effect between semi-inclusive DIS and the
Drell-Yan process. An x-dependent version of the
Ehrnsperger-Schaefer-Greiner-Mankiewicz relation between the Qiu-Sterman
function and a twist-3 part of g_2 is presented, which naturally suggests a
node in the Qiu-Sterman function. This relation could be checked experimentally
as well and could provide qualitative information on the gluonic field strength
inside the proton. Satisfying the Burkardt sum rule by means of a node is
briefly discussed and the importance of modelling the Sivers function including
its full Wilson line is pointed out.
