  The production of hyperons in Pb-Pb and p-Be interaction at 40 A GeV/c beam
momentum has been measured by the NA57 experiment. Strange particle
enhancements at 40 A GeV/c are presented for the first time and compared to
those measured at 158 A GeV/c. The transverse mass spectra of high statistics,
high purity samples of K0_short, Lambda, Xi and Omega particles produced in
Pb-Pb collisions at 158 A GeV/c have been studied in the framework of the
blast-wave model. The dependence of the freeze-out parameters on particle
species and event centrality is discussed.
