  Using ideas underlying the flavour-blind "Nijmegen Unitarised Meson Model" we
try to understand on the basis of a system of Schroedinger equations with one
meson-meson and one (spinless) quark-antiquark channel coupled by a simple
delta-shell transition potential the formation of (e.g. scalar) meson-meson
scattering singularities in the complex momentum and energy plane. Surprisingly
we are able to describe without direct meson-meson interaction and without any
need for glueballs the whole known scalar meson spectrum. "Light" scalar mesons
(e.g. f0(600), kappa(800), f0(980), a0(985), D*0(2290), ...) are identified to
belong to the spectrum of the transition potential, while "heavy" scalars (e.g.
f0(1370), K*0(1430), f0(1500), f0(1710), a0(1450), D*0(2621) (?), D*0(2825)
(?), D*sJ(2928) (?), ...) are related to the confinement spectrum. Due to the
particular value of the charm-strange reduced quark mass level-(anti)crossing
in the complex momentum plane occurs which relates the BABAR state Ds(2317) to
the bare groundstate of the confinement spectrum, while the respective
groundstate of the transition potential ends up as D*sJ(2782) (?). We conclude
with a short comment on (our) recent progress in the consistent quantum field
theoretical effective description of resonances within a Lagrangian framework.
