  We introduced recently a new theoretical scheme which accounts for
hydrodynamically expanding bulk matter, jets, and the interaction between the
two. Important for the particle production at intermediate values of transverse
momentum (p_t) are jet-hadrons produced inside the fluid. They pick up quarks
and antiquarks (or diquarks) from the thermal matter rather than creating them
via the Schwinger mechanism -- the usual mechanism of hadron production from
string fragmentation. These hadrons carry plasma properties (flavor, flow), but
also the large momentum of the transversely moving string segment connecting
quark and antiquark (or diquark). They therefore show up at quite large values
of p_t, not polluted by soft particle production. We will show that this
mechanism leads to a pronounced peak in the lambda / kaon ratio at intermediate
p_t. The effect increases substantially with centrality, which reflects the
increasing transverse size with centrality.
