A return to time, cells, systems, and aging: IV. Further thoughts on Gompertzian survival dynamics--the neonatal years.

In this paper, I attempt to address the problem of how to model the survival curve in the early lifespan years; the neonatal years. I present a general model for a two group population in which the first group represents early stage failure and the second group represents the classical Gompertzian failure. After calculating the instantaneous failure rate for this population, I compare it to the single group Gompertzian with log-linear instantaneous failure rate. The theoretical results are then compared to the known biological data. It is demonstrated that this new model embeds, within itself, a variety of the known biological survival dynamics.