$\dedx$ spectra for secondary pions (open triangles) and protons (full circles) identified via the reconstruction of the weak decay topology of ${\rm K_{S}^{0}}$ and $\Lambda$, respectively. The spectra have been normalized to have the same integrals. The spectrum for primary pions (full triangles) is obtained by requiring $\beta_{\rm TOF} > 1$. Results for peripheral (upper panel) and central (lower panel) $\pbpb$ collisions are shown. The tracks were chosen in the momentum (pseudorapidity) interval $5< p< \gevc{7}$ ($0.6\leq|\eta|< 0.8$). Note that most spectra also contain a well-understood background.