Inversion of the broken ray transform in the case of energy-dependent attenuation.

Broken Ray transform (BRT) arises when one considers a narrow x-ray beam propagating through medium under the assumption of single scattering. Previous algorithms for inverting the BRT assumed that the medium is characterized by a single attenuation coefficient μ. However x-rays lose their energy after Compton scattering and the energy loss depends on the scattering angle.

A study on HIV and hepatitis C virus among commercial sex workers in Tallinn.

Introduction: Estonia is confronted by a dramatic expansion of the initially injection drug use-driven HIV epidemic. Little is known about HIV occurrence in population groups at high risk other than injection drug users.

Objective: To obtain data on the prevalence of HIV and hepatitis C virus (HCV) among female sex workers (FSW) in Tallinn.