Beecroft Institute for Particle Astrophysics and Cosmology

Abstract:

We report on the development of a new method for detecting automatically malignant masses in digitised mammograms, based on a novel non-linear method of multiscale analysis. We show that it is possible to detect > 85 percent of all malignant masses by this method, irrespective of their size, with a false-alarm rate that is close to acceptable for asymptomatic screening.

Abstract:

We examine how the qualitative structure of the Doppler peaks in the angular power spectrum of the cosmic microwave anisotropy depends on the fundamental nature of the perturbations which produced them. The formalism of Hu and Sugiyama is extended to treat models with cosmic defects. We discuss how perturbations can be ``active'' or ``passive'' and ``incoherent'' or ``coherent'', and show how causality and scale invariance play rather different roles in these various cases. We find that the existence of secondary Doppler peaks and the rough placing of the primary peak unambiguously reflect these basic properties.