We extend the classical Ostrowski numeration systems, closely related to Sturmian words, by allowing a wider range of coefficients, so that possible representations of a number n better reflect the structure of the associated Sturmian word. In particular, this extended numeration system helps to catch occurrences of palindromes in a characteristic Sturmian words and thus to prove for Sturmian w...

Advancing adult age is associated with functional declines in both the sensory and perceptual stages of visual information processing (see Schieber, 1992). This paper reviews the recent research literature (i.e., 1988-1994) which has attempted to assess the impact of age-related visual declines upon driving mobility, safety and performance. VISION LOSS AND DRIVING MOBILITY In a 10-year longitud...

Frank Gower Bergin passed away in his sleep on October 25th, after a prolonged period of restricted activity due to cardiac weakness. His father and brother were at one time Directors of Muller's Orphanage; two brothers were doctors, and a sister was for a while Casualty Sister at the General Hospital. With the late James Taylor, he pioneered radiological services in Bristol, working for many y...