Showing papers by "University of Westminster published in 1988"

Morpholexical rules and lexical representation

Abstract: This paper expands on Lieber's (1980) claim that certain instances of allomorphy must be determined before word-formation processes apply. Her notion of 'morpholexical rule' is reinterpreted as a structure-building lexical-redundancy rule. Such rules are triggered by morpholexical or morphosyntactic features assigned to lexical entries. The morpholexical rules specify phonological structure which is predictable, either from general principles or from morpholexical class membership. It is argued that in certain cases the lexical representations so constructed resemble the structures of nonconcatenative morphologies, in that they are multiplanar, with separate tiers corresponding to different morphosyntactic or morphophonological categories. Linguistic and psycholinguistic evidence is presented in support of these claims.

A new form of damage to PMMA intraocular lenses by Nd: YAG laser photodisruptors

Abstract: The damage that Nd:YAG laser radiation can cause to plastic (PMMA) IOLs during pseudophakic capsulotomy is well documented in the literature. This damage is the result of direct plasma action on the lens material. We report here another form of damage to PMMA IOLs which is more subtle and does not result from plasma action in the plastic. Even when the irradiance within the IOL is well below the threshold for optical breakdown, the PMMA can be damaged if irradiated by many laser pulses. This subthreshold damage is therefore cumulative. Its importance, likelihood of occurrence and ways to minimise this are considered.