Longitudinal ageing model
Trajectories of senescence through Markov models
At the time of the project, the theory of ageing currently had to get by without a useable operational definition of its central object, ageing. Instead, coarse proxies stood in for ageing, whether mortality or changes in fertility.
Experiments designed by teams in California and Mexico took place to study the life course of ageing in fruit flies, one of the standard model organisms. Flies in these experiments had their behaviour continuously recorded over their entire lifespans, with the goal of understanding how changes in behaviour might signal underlying changes in the inherent senescence state.
This project developed statistical methods to
organise and structure the data
recognise the signal of senescence in this mass of data
link the senescence signal to mathematical models which have been central to the theoretical study of ageing.
The basic object was a kind of Hidden Markov Model, adapted to this particular structure of observations.
We developed both the basic theoretical statistics of this model and a practical computational algorithm, tested the procedure on simulated data, and helped the experimental teams with the data analysis as the results became available.
Trajectories of senescence through Markov models (PDF, 768KB)
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For more information, read the full project details.