We have developed three instruments for accurate measurement of optieal fiber cladding diameter: a contact micrometer, a scanning confocal microscope, and a white-light interference microscope. Each instrument has an estimated uncertainty (3 standard deviations) of 50 nm or less, but the confocal microscope may display a 20 nm systematic error as well. The micrometer is used to generate Standar...

The aim of this study is to compare the diameters of proximal and distal common bile duct (CBD) using magnetic resonance cholangiopancreatography (MRCP). The results may help in the daily MR interpretation of CBD and hepa-

Introduction Forest ecologists use the frequency distribution of d.b.h. (diameter at breast height, 1.35 m above ground) of the stems of woody species to describe age/size structures and draw inferences about regeneration strategies, synchrony of climatic events, mortality patterns and the effects of animal browsing (e.g. recent New Zealand studies by Allen, Payton and Knowlton, 1984; Mark, 196...