  Strangeness enhancement and collective flow are considered signatures of the
quark gluon plasma formation. These phenomena have been detected not only in
relativistic heavy ion collisions but also in high energy, high multiplicity
events of proton-proton and proton-nucleus (small systems) scatterings. A
universal behavior emerges by considering the parton density in the transverse
plane as the dynamical quantity to specify the initial condition of the
collisions, which in electron-positron annihilation at the available energies
is too low to expect collective effects.
