This paper discusses numerical experiments of wave front propagation on a flat disk and related results. In particular, notions of extremal rays and wave front caustics are introduced to investigate the dynamic behaviors of wave fronts under repeated reflection. These results are related to earlier work on caustics of ray systems. It is shown that wave fronts require a modified notion of causti...

Acute β-adrenergic blockade increases aortic wave reflection; however, the mechanisms remain unclear. Evidence suggests that β-adrenergic receptor sensitivity in the peripheral vasculature differs between sexes. Therefore, the goal of this study was to examine whether β-adrenergic blockade alters aortic wave reflection to a similar extent in young men and women. In 31 subjects (16 men and 15 wo...

Acute -adrenergic blockade increases aortic wave reflection; however, the mechanisms remain unclear. Evidence suggests that -adrenergic receptor sensitivity in the peripheral vasculature differs between sexes. Therefore, the goal of this study was to examine whether -adrenergic blockade alters aortic wave reflection to a similar extent in young men and women. In 31 subjects (16 men and 15 women...

The spark shadowgram method of studying shock waves is described. It has been used to investigate the properties of such waves produced by the impact of a high velocity missile on the surface of water. The method can be adapted for study of behavior of shock waves in tissue by placing the tissue on a water surface or immersing it in water. Spark shadowgrams then reveal waves passing from tissue...

We study fermion reflection at a phase wave which is formed during a bubble collision in a first order phase transition. We calculate the reflection and the transmission coefficients by solving the Dirac equation with the phase wave background. Using the results we analyze the damping and the velocity of the

We reveal the basic mechanism of instability of the two-layer conductive fluid system carrying a normal current and exposed to a uniform external magnetic field. This process is a reflection of a MHD-modified interfacial gravity wave from the boundary. Due to special boundary conditions, the reflection coefficient turns out to be greater than 1 for some directions of the wave propagation. We co...

We consider the problem of quantum ‘‘reflection above the barrier,’’ introducing a distorted-wave Born approximation based on the primitive semiclassical Wentzel-Kramers-Brillouin wave function. The idea generalizes to the concept of an unperturbed Hamiltonian defined as the exact Hamiltonian plus small parts which ‘‘turn off’’ nonclassical processes such as barrier reflection and barrier tunne...

BACKGROUND Acute beta-adrenergic blockade increases aortic-wave reflection in young women. However, it is not known whether this effect extends to postmenopausal women. We therefore examined the effect of systemic beta-adrenergic blockade on aortic wave reflection in 14 postmenopausal women with a mean age of 58±2 years. METHODS Aortic pressure waveforms were synthesized noninvasively from high...

In recent years, borehole Stoneley wave amplitude and reflectivity have been used for estimating formation permeability based on the strong correlation between Stoneley wave attenuation, reflectivity and formation fluid conductivity. There are other factors, however, that may cause substantial Stoneley attenuation and reflection in a borehole environment. To make better use of Stoneley measurem...