Age, body mass index, and functional illness.

OBJECTIVES: This study examines the relationship between body mass index (BMI) and selected measures of functional illness and whether the relationship between BMI and these outcomes is stronger in advanced ages. METHODS: Four measures of functional illness were examined in national, longitudinal survey of noninstitutionalized adults. Tobit and Poisson models were used to estimate cross-sectional and longitudinal specifications. RESULTS: BMI was related to functional illness but not in a linear form: Both obese and underweight persons manifested higher levels of functional illness on most outcomes during the baseline survey. Results from the change analyses, however, revealed that obesity was associated with more days hospitalized or ill in bed and an increase in functional limitations. DISCUSSION: Obesity is associated with functional illness, but there is no evidence from these data that this relationship is stronger for older adults. Rather, the effect of obesity on some measures of functional illness is greater in the younger and middle ages.

Grammatical inference: introduction and survey-part I.

The problem of grammatical inference is introduced, and its potential engineering applications are demonstrated. Inference algorithms for finite-state and context-free grammars are presented. The application of some of the algorithms to the inference of pattern grammars in syntactic pattern recognition is illustrated by examples.

Grammatical Inference: Introduction and Survey-Part II.

Inference of high-dimensional grammars is discussed. Specifically, techniques for inferring tree grammars are briefly presented. The problem of inferring a stochastic grammar to model the behavior of an information source is also introduced and techniques for carrying out the inference process are presented for a class of stochastic finite-state and context-free grammars. The possible practical application of these methods is illustrated by examples.