Modeling XXXX under a time-changing exposure.

@entity5 @entity105 @entity19 @entity706
A model of @entity105 for fractionated and continuous exposure is developed. The model is discussed from two points of view. First a "surface" statistical model is introduced by making assumptions about the hazard function for the time of @entity5 latency. Later it is shown that the model can be interpreted in a mechanistic sense as a discrete and a mixed discrete/continuous counterpart of a model of @entity105 recently proposed by Yakovlev and Polig [A. Yakovlev, E. Polig, Math. Biosci. 132 (1996) 1]. Two counteracting effects are combined: a protective multiplicative effect of the exposure on the hazard function along with an additive effect of @entity5 responsible for an additional hazard. The model is used to revisit the analysis by Yakovlev et al. [A. Yakovlev, W. M  ller. L. Pavlova, E. Polig, Math. Biosci. 142 (1997) 107] of @entity706 in irradiated @entity19 under acute and fractionated exposure.
