We have examined the propagation of femtosecond laser pulses in an absorbing dye solution through a short to a long range of propagation distance. The transmitted pulses show strong spectral shift and a superluminal to subluminal transition in the propagation velocity keeping its initial shape almost intact. It is verified that the peak velocity is well described by a modified group velocity v(S) defined within the framework of the saddle-point method as well as by a recent prediction of the net group delay of surviving frequency.

To analyze how the 1-min oscillation in postural sway and 1-min wave in body fluid volume change contribute to human circulatory homeostasis, several levels of body circumference, foot pressure center, electromyograms, and volumes of the leg, abdomen, and thorax were measured during upright standing for 40 min in 20 healthy young men. Spectral analyses of these parameters revealed that a 1-min rhythm is found in all parameters and that the 1-min wave in body fluid volume changes in the lower leg, which occur in fluid pooling caused by gravity, propagate upward. Muscle pumping in the lower leg triggered by the postural sway was found to increase the power of this 1-min wave. A quantitative analysis of body circumferences disclosed that the 1-min wave in body fluid volume change compensates for gravitational downward fluid shift, with the volume of 6.3 +/- 5.0 ml/cycle at the heart level. We concluded that a coupling mechanism between the 1-min oscillation in postural sway and the upward propagation of 1-min wave in body fluid volume change contributes to maintain systemic blood pressure during upright standing in humans.

No abstract

In our statement (v), as well as in the text thereafter, the words "thermal radiation" must, in the general case, be replaced by "coherent radiation with thermal photon statistics." We thank J. Gea-Banacloche for calling our attention to this imprecision. The experimentally most important case, however, namely the spontaneous rise of a longitudinal polarization, which may be mistaken for a parity nonconservation effect, does occur also for truly thermal radiation: ( 1. New Monte Carlo Algorithm: Entropic Sampling [Phys. Rev. Lett. 71, 211 (1993)]Jooyoung Lee I would like to cite several important works omitted, where related simulation methods for the calculation of the density of state were proposed. They are as follows: G. M. Torrie and J. P. Valleau, J.

Non-axisymmetric Alfvén waves are excited with a helical coupler in a finite beta and a cylindrical inhomogeneous plasma surrounded by a conducting wall. The helical coupler, which consists of two symmetrical helical windings, exhibits a strong propagation directionality; slow waves of the m=-1 mode and fast waves of the m=+1 mode can be launched simultaneously from the coupler, but propagate in opposite directions along the static magnetic field. Dispersion relations including the attenuation length for both modes are compared with a magnetohydrodynamic theory given by Woods on the assumption of appropriate boundary conditions. As a nonlinear phenomenon, subharmonic slow Alfvén waves of the m=-1 mode have been observed when the pump frequency is close to or above the ion cyclotron frequency.