Ricerc@Sapienza

We prove an Lp estimate (Equation Presented) for the Schrödinger group generated by a semibounded, self-adjoint operator L on a metric measure space X of homogeneous type (where n is the doubling dimension of X). The assumptions on L are a mild Lp0 → Lp' 0 smoothing estimate and a mild L2 → L2 off-diagonal estimate for the corresponding heat kernel e -tL. The estimate is uniform for φ varying in bounded sets of S(R), or more generally of a suitable weighted Sobolev space.

Typhoid perforation is the most fatal complication of typhoid fever in developing countries and is most often caused by the bacteria Salmonella Typhi. There are conflicting views as to which type of surgical intervention gives the best outcome. The aim of this study was to determine the mortality associated with the different types of surgical interventions employed in patients with typhoid perforation.