16 research outputs found
Analytical solution of a generalized Penna model
In 1995 T.J.Penna introduced a simple model of biological aging. A modified
Penna model has been demonstrated to exhibit behaviour 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,
able to deal with arbitrary birth and survivability functions. This solution is
employed to solve standard variant Penna models studied by simulation.
Different Verhulst factors regulating both the birth rate and external death
rate are considered.Comment: 6 figure
Biologia floral, sistema reprodutivo e métodos artificiais de hibridação de Hemerocallis hybrida
Fenologia e biologia reprodutiva de duas espécies de Byrsonima Rich. (Malpighiaceae) em área de Cerrado no Nordeste do Brasil
Damage Spreading in Asymmetric Ising Spin Glasses
Spin glasses in dimensions 2, 3, 4 and mean field are studied numerically as a function of the
degree of asymmetry of the interactions between spins. Damage spreading data are used to assess the
effects on the spin glass ordering of introducing asymmetry in the couplings. In all dimensions the
critical temperature for damage spreading is rather insensitive to the asymmetry, but the spin glass
ordering is strongly suppressed by any finite degree of asymmetry. We discuss the physical
significance of the damage spreading parameter