The renormalized Euler Characteristic and L-space surgeries

Using the equivalence between the renormalized Euler characteristic of Ozsvath and Szabo, and the Turaev torsion normalized by the Casson-Walker invariant, we make calculations for $S_{p\mathrm{/}q}^3(K)$. An alternative proof of a theorem by Ozsv'ath and Szab'o on $L$-space surgery obstructions is provided.