Let M be a connected, simply oriented, closed, smooth four-manifold which is spin (or equivalently having even intersection form) and put M×?M?{point}. In this paper we prove that if X× homeomorphic but not necessarily diffeomorphic to M× (more precisely, it carries structure à la Gompf) then can equipped with complete Ricci-flat Riemannian metric. As byproduct of the construction follows metri...

A radiative transfer equation is used to model the diffuse multiple scattering of ultrasound in a medium containing discrete random scatterers. An assumption of uncorrelated phases allows one to write an equation of energy balance for the diffuse intensity. This ultrasonic radiative transfer equation contains single-scattering and propagation parameters that are calculated using the elastic wav...