Approaches to the space-time modelling of infectious disease behaviour

A new approach to the space-time modelling of infectious diseasesis considered. A modulated heterogeneous Poisson process withintensity defined as a function of a two-dimensional susceptibilityfield is proposed. The model is fitted to a measles epidemicusing a proportional hazards approximation.     

PTERIN- AND FLAVIN-LIKE FLUORESCENCE ASSOCIATED WITH ISOLATED FLAGELLA OF Euglena gracilis

Fluorescence excitation- and emission spectra indicate the presence of pterin(s) and flavin(s) in isolated flagella of the phytoflagellate Euglena gracilis. These compounds appear to bind at least in part non-covalently to the molecular framework of the paraflagellar body, which is the presumed photoreceptor organelle and which is attached to the isolated flagella. A compound with pterin-like fluorescence excitation and emission spectrum could he extracted with methanol from isolated flagella and could he recovered on thin-layer silica gels. Besides the previously assumed photoreceptor function of flavins, our results suggest also a role for pterins in the photosensory transduction chain of Euglena gracilis.