Professor David Steinsaltz
Stochastic processes, biodemography, mathematical biology, random dynamical systems, meta-analysis, human sex ratio, hidden Markov models
I am currently interested primarily in biological and demographic questions connected with ageing and mortality. Attempts to understand ageing in a broad biological context, in particular evolutionary models, have suffered at times from antiquated mathematical technology. I am part of a loosely organised international collaborative effort, including laboratory biologists, field biologists, demographers, economists, statisticians, mathematicians, and maybe some others, working to bring modern mathematical and statistical technology to bear on the major theoretical problems of ageing: Why do organisms senesce (i.e., deteriorate in physiological function as they age)? Why do some organisms apparently not senesce? Why do organisms show the patterns of age-related change that they do, and how is this linked to other characteristics of their life course?
The underlying principle of biodemography is that we can begin to answer these questions only by linking a sophisticated understanding of population-level processes to an equally sophisticated model of physiology, with bonds I develop mathematical models, generally of a stochastic nature, for population-level evolutionary processes and for individual physiology; I refine statistical techniques for novel ageing-related experiments, and plan new experiments; I analyse demographic data, both traditional (human vital statistics) and offbeat (damage-splitting in yeast). Most recently, this has led me into an interest in non-stationary hidden Markov models, meta-analysis for complex survey data, and the demography of human gestation.
I also continue to be interested in fundamental questions of stochastic processes, in particular the behaviour of stochastic flows, the asymptotics of killed Markov processes and random fixed points for iterated function systems.
"Derivatives of the Stochastic Growth Rate" appeared TPB Volume 80, Issue 1, August 2011, Pages 1–15
"Necessary and sufficient conditions..." appeared Ann. Probab. Volume 40, Number 1 (2012), 162-212
With Steven N. Evans and Kenneth W. Wachter: "A mutation-selection model for general genotypes with recombination".(Accepted for publication Memoirs of the American Mathematical Society). 2011
With Stephen Orzack: "Statistical methods for paleodemography on fossil assemblages having small numbers of specimens: an investigation of dinosaur survival rates", Journal of Palaeontology, January 2011.
With Shripad Tuljapurkar and Carol Horvitz: "Derivatives of the Stochastic Growth Rate". (Accepted Theroetical Population Biology) 2010.
With Kenneth W. Wachter and Steven N. Evans: "Vital Rates from the Action of Mutation Accumulation". Journal of Population Ageing (2010).
With Martin Kolb: "Necessary and sufficient conditions for convergence to quasistationary distributions for one-dimensional diffusions with killing". (Accepted Annals of Probability).
With Kelvin Yen and Charles Mobbs: "Validated analysis of mortality rates demonstrates distinct genetic mechanisms that influence lifespan". Experimental Gerontology, 43: 12 (2008), pp. 1044-51.
With Steven N. Evans: "Damage segregation at fissioning may increase growth rates: A superprocess model". Theoretical Population Biology 71: 4 (2007), pp. 473- 90
With Steven N. Evans: "Quasistationary distributions for one-dimensional diffusions". Trans Amer Math Soc 359:3 (March 2007), pp. 1285--1324.
With Steven N. Evans and Kenneth W. Wachter: "A generalized model of mutation-selection balance with applications to aging". Adv Appl Math 35:1 (2005), pp. 16—33.
With Kenneth W. Wachter: "Understanding mortality rate deceleration and heterogeneity". Math Pop Stud, 13:1 (2006), pp. 19—37.
With M. Scheutzow: "Chasing balls through martingale fields". Ann Prob 4/2002, pp. 2046-80.
I moved to Oxford from Queen’s University in Kingston, Ontario, where I was associate professor in the department of mathematics and statistics. Before then I spent four years as a researcher on a K12 grant in the department of demography at UC Berkeley, following on 2 ½ years in the department of statistics of the same august institution. I was a postdoc at the Technical University of Berlin, and briefly at the Technical University of Delft. I did my PhD in probability theory with Persi Diaconis.