64 research outputs found
Catastrophic senescence of the Pacific salmon without mutation-accumulation
We derive catastrophic senescence of the Pacific salmon from an aging model
which was recently proposed by Stauffer. The model is based on the postulates
of a minimum reproduction age and a maximal genetic lifespan. It allows for
self-organization of a typical age of first reproduction and a typical age of
death. Our Monte Carlo simulations of the population dynamics show that the
model leads to catastrophic senescence for semelparous reproduction as it
occurs in the case of salmon, but to a more gradually increase of senescence
for iteroparous reproduction.Comment: 7 pages, latex2e, 2 postscript figures, to be published in Int. J.
Mod. Phys. C12(3) 200
Competition of Languages and their Hamming Distance
We consider the spreading and competition of languages that are spoken by a
population of individuals. The individuals can change their mother tongue
during their lifespan, pass on their language to their offspring and finally
die. The languages are described by bitstrings, their mutual difference is
expressed in terms of their Hamming distance. Language evolution is determined
by mutation and adaptation rates. In particular we consider the case where the
replacement of a language by another one is determined by their mutual Hamming
distance. As a function of the mutation rate we find a sharp transition between
a scenario with one dominant language and fragmentation into many language
clusters. The transition is also reflected in the Hamming distance between the
two languages with the largest and second to largest number of speakers. We
also consider the case where the population is localized on a square lattice
and the interaction of individuals is restricted to a certain geometrical
domain. Here it is again the Hamming distance that plays an essential role in
the final fate of a language of either surviving or being extinct.Comment: 18 pages, 19 figure
- …