The percolation model of stock market speculation allows an asymmetry (in the return distribution) leading to fast downward crashes and slow upward recovery. We see more small upturns and more intermediate downturns.

The percolation model of Cont and Bouchaud for the herding of noise traders is generalized to take into account also the fundamental value of the traded object, not only the behaviour of other traders. Monte Carlo simulations with 10012 and 77 traders give no drastic change in the histogram of...

After parameterizing the local environments of amino acids into nine categories depending on three secondary structures and three kinds of hydrophobicity (solvation) of amino acids, we could design and construct the 16,290 pairwise-contact energy parameters of amino acids by the quasi-chemical...

In Penna's model for biological ageing we reduce after equilibration the influence of acquired diseases and get, similar to reality, the observed increase of the Gompertz slope for the human mortality curves.

The dynamics of individual characteristics of economic agents is modeled with the link structure influenced by this dynamics: links between agents with similar characteristics are more stable than those between agents with vastly different characteristics. A simple scaling law describes the...

Ecology and evolution are inseparable. Motivated by some recent experiments, we have developed models of evolutionary ecology from the perspective of dynamic networks. In these models, in addition to the intra-node dynamics, which corresponds to an individual-based population dynamics of...

On a hypercubic lattice with L7 sites and L up to 21, the site percolation threshold for the spanning of a cluster from top to bottom is found to approach its asymptotic value with a 1/L law, in contrast to the Ising Curie temperature in five dimensions.

The evolution of money from unsuccessful barter attempts, as modeled by Donangelo and Sneppen, is modified by a deterministic instead of a probabilistic selection of the most desired product as money. We check in particular the characteristic times of the model as a function of system size.

In the marketing model of Solomon and Weisbuch, people buy a product only if their neighbours tell them of its quality, and if this quality is higher than their own quality expectations. Now we introduce additional information from the mass media, which is analogous to the ghost field in...

Within the Penna model of biological ageing, we show that longevity is heritable, for both sexual and asexual reproduction.