The enhancement of the scalar-isoscalar spectral function near the two-pion
threshold is studied in the framework of an effective linear σ model,
using a large N approximation in the number of the Goldstone bosons. The effect
is rather insensitive to the detailed T=0 characteristics of the σ pole,
it is accounted by a pole moving with increasing T along the real axis of the
second Riemann sheet towards the threshold location from below.Comment: 5 pages, poster presented at SEWM2002, Heidelberg, October 200