Anomalous Heat Conduction in Quasi-One-Dimensional Gases

From three-dimensional linearized hydrodynamic equations, it is found that the heat conductivity is proportional to $(L_x/(L_y^2 L_z^2))^{1/3}$, where $L_x$, $L_y$ and $L_z$ are the lengths of the system along the $x$, $y$ and $z$ directions, and we consider the case in which $L_x \gg L_y, L_z$. The necessary condition for such a size dependence is derived as $\phi \equiv L_x/(n^{1/2} L_y^{5/4} L_z^{5/4}) \gg 1$, where $\phi$ is the critical condition parameter and $n$ is the number density. This size dependence of the heat conductivity has been confirmed by molecular dynamics simulation.Comment: 10 pages, 4 figure

Suprachiasmatic nuclei and Circadian rhythms. The role of suprachiasmatic nuclei on rhythmic activity of neurons in the lateral hypothalamic area, ventromedian nuclei and pineal gland

Unit activity of lateral hypothalamic area (LHA) and Ventromedian nuclei (VMN) was recorded in urethane anesthetized male rats. A 5 to 10 sec. a 3-5 min and a circadian rhythmicity were observed. In about 15% of all neurons, spontaneous activity of LHA and VMN showed reciprocal relationships. Subthreshold stimuli applied at a slow rate in the septum and the suprachiasmatic nuclei (SCN) suppressed the rhythms without changing firing rates. On the other hand, stimulation of the optic nerve at a rate of 5 to 10/sec increased firing rates in 1/3 of neurons of SCN. Iontophoretically applied acetylcholine increased 80% of tested neurons of SCN, whereas norepinephrine, dopamine and 5 HT inhibited 64, 60 and 75% of SCN neurons respectively. These inhibitions were much stronger in neurons, the activity of which was increased by optic nerve stimulation. Stimulation of the SCN inhibited the tonic activity in cervical sympathetic nerves

Scaling Relation for Excitation Energy Under Hyperbolic Deformation

We introduce a one-parameter deformation for one-dimensional (1D) quantum lattice models, the hyperbolic deformation, where the scale of the local energy is proportional to cosh lambda j at the j-th site. Corresponding to a 2D classical system, the deformation does not strongly modify the ground state. In this situation, the effective Hamiltonian of the quantum system shows that the quasi particle is weakly bounded around the center of the system. By analyzing this binding effect, we derive scaling relations for the mean-square width of confinement, the energy correction with respect to the excitation gap \Delta, and the deformation parameter $\lambda$. This finite-size scaling allows us to investigate excitation gap of 1D non-deformed bulk quantum systems.Comment: 9 pages, 5 figure

Critical Point of a Symmetric Vertex Model

We study a symmetric vertex model, that allows 10 vertex configurations, by use of the corner transfer matrix renormalization group (CTMRG), a variant of DMRG. The model has a critical point that belongs to the Ising universality class.Comment: 2 pages, 6 figures, short not