Phylogenetic tree and community structure from a Tangled Nature model.

In evolutionary biology, the taxonomy and origination of species are widely studied subjects. An estimation of the evolutionary tree can be done via available DNA sequence data. The calculation of the tree is made by well-known and frequently used methods such as maximum likelihood and neighbor-joining.

Search for the global minimum structures of AlB3H(2n) (n = 0 - 6) clusters.

The global minimum structures of AlB3H2n (n = 0-6) clusters are determined using the stochastic search method at the B3LYP/6-31G level of theory. These initially specified geometries are recalculated using B3LYP and CCSD(T) methods using the 6-311++G(**) basis set. The structural and electronic properties of the two lowest-lying isomers are presented.

Kinetics of a mixed spin-1 and spin-3/2 Ising system under a time-dependent oscillating magnetic field.

We present a study, within a mean-field approach, of the kinetics of the mixed spin-1 and spin-3/2 Ising model Hamiltonian with bilinear and biquadratic nearest-neighbor exchange interactions and a single-ion potential or crystal-field interaction in the presence of a time-dependent oscillating external magnetic field. We employ the Glauber transition rates to construct the mean-field dynamical equations. We investigate the time dependence of average magnetizations and the quadrupole moments, and the thermal behavior of the dynamic order parameters.

Crystal field effect on a bilayer Bethe lattice.

The influence of the crystal field on the phase diagrams of the bilayer spin-1 Ising model on the Bethe lattice is studied in terms of the intralayer coupling constants J1 and J2 of the two layers and interlayer coupling constant J3 between the layers for given values of the coordination number q by using the recursion relation scheme. The six distinct ground-state configurations of the model are obtained on the (J_{2}J_{1},J_{3}qJ_{1}) plane with J1>0 , the ferromagnetic coupling, for given values of the crystal field. Then, the phase diagram of the system is obtained on the (kTJ_{1},J_{3}J_{1}) plane for given values of the crystal field and alpha=J_{2}J_{1} with q=4 corresponding to the square lattice in real lattice systems.

Dynamic phase transition in the kinetic spin- Blume-Capel model under a time-dependent oscillating external field.

We present a study, within a mean-field approach, of the stationary states of the kinetic spin-3/2 Blume-Capel model in the presence of a time-dependent oscillating external magnetic field. We use the Glauber-type stochastic dynamics to describe the time evolution of the system. We have found that the behavior of the system strongly depends on the crystal-field interaction.

Dynamic phase transition in the kinetic spin-1 Blume-Capel model under a time-dependent oscillating external field.

We study within a mean-field approach the stationary states of the kinetic spin-1 Blume-Capel model in the presence of a time-dependent oscillating external magnetic field. We use the Galuber-type stochastic dynamics to describe the time evolution of the system. We have found that the behavior of the system strongly depends on the crystal field interaction D .