  Recent Deep Inelastic data leads to an up-down quark asymmetry of the nucleon
sea. Explanations of the flavour asymmetry and the di-lepton production in
proton-nucleus collisions call for a temperature $T \approx 100$ MeV in a
statistical model. This T may be conjectured as being due to the
Fulling-Davies-Unruh effect. But it is not possible to fit the structure
function itself.
