4,225 research outputs found
Anomalous Heat Conduction in Quasi-One-Dimensional Gases
From three-dimensional linearized hydrodynamic equations, it is found that
the heat conductivity is proportional to , where
, and are the lengths of the system along the , and
directions, and we consider the case in which . The necessary
condition for such a size dependence is derived as , where is the critical condition parameter
and 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 . 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
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