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- N H Barton, J B Coe
- Journal of theoretical biology
- 2009

There is a close analogy between statistical thermodynamics and the evolution of allele frequencies under mutation, selection and random drift. Wright's formula for the stationary distribution of allele frequencies is analogous to the Boltzmann distribution in statistical physics. Population size, 2N, plays the role of the inverse temperature, 1/kT, and… (More)

We present some analytic results for the steady states of the Penna model of senescence, generalized to allow genetically identical individuals to die at different ages via an arbitrary survival function. Modeling this with a Fermi function (of modest width) we obtain a clear mortality plateau late in life: something that has so far eluded explanation… (More)

The Penna model is a model of evolutionary ageing through mutation accumulation where traditionally time and the age of an organism are treated as discrete variables and an organism's genome is represented by a binary bit string. We reformulate the asexual Penna model and show that a universal scale invariance emerges as we increase the number of discrete… (More)

The Gaia hypothesis [Lovelock, J., Margulis, L., 1974. Atmospheric homeostasis: the Gaia hypothesis. Tellus 26, 1], that the earth functions as a self-regulating system, has never sat particularly comfortably with ideas in mainstream biology [Anon, 2002. In pursuit of arrogant simplicities. Nature 416, 247]. A lack of any clear role for evolution in the… (More)

- Josh Coe, Mon-Chu Chen
- CHI Extended Abstracts
- 2010

Cultural problems exist with current online systems for meeting new people, such as dating sites, which encourage unnatural meetings with strangers. An SMS-based murder mystery game was designed to facilitate the natural progression of growing one's personal network by meeting friends of friends. Considerations on how a location-based mobile system could… (More)

A random cellular automaton is one in which a cell's behaviour is independent of its previous states. Analytical conditions for the existence of random cellular automata are derived and we find that a multitude of non-trivial random cellular automata exist. We develop an indicator variable formalism to further investigate these random automata and confirm… (More)

In 1995 Penna introduced a simple model of biological aging. A modified Penna model has been demonstrated to exhibit behavior of real-life systems including catastrophic senescence in salmon and a mortality plateau at advanced ages. We present a general steady-state, analytic solution to the Penna model which is able to deal with arbitrary birth and… (More)

We build upon our previous analytical results for the Penna model of senescence to include positive mutations. We investigate whether a small but nonzero positive mutation rate gives qualitatively different results to the traditional Penna model in which no positive mutations are considered. We find that the high-lifespan tail of the distribution is… (More)

We build upon the recent steady-state Penna model solution [J. B. Coe, Y. Mao, and M. E. Cates, Phys. Rev. Lett. 89, 288103 (2002)] to study the population dynamics within the Penna model. We show that any perturbation to the population can be broken into a collection of modes each of which decay exponentially with its respective time constant. The long… (More)

- J G Voet, J Coe, J Epstein, V Matossian, T Shipley
- Biochemistry
- 1981

The dissociation constant of an essential acidic group on the reduced form of glucose oxidase from Aspergillus niger (K4) has been found to be extremely sensitive to ionic strength. Increasing the ionic strength from 0.025 to 0.225 causes a decrease in pK4,obsd of 0.9 pH unit, from 8.2 to 7.3. Analysis of the ionic strength dependence of pK4,obsd, making… (More)