  We report on the optimized production of a Bose-Einstein condensate of cesium
atoms using an optical trapping approach. Based on an improved trap loading and
evaporation scheme we obtain more than $10^5$ atoms in the condensed phase. To
test the tunability of the interaction in the condensate we study the expansion
of the condensate as a function of scattering length. We further excite strong
oscillations of the trapped condensate by rapidly varying the interaction
strength.
