Letter by O’Rourke et al Regarding Article, “Arterial Stiffness and Cardiovascular Events: The Framingham Heart Study” To the Editor: The article by Mitchell et al1 confirms the value of carotid-femoral pulse-wave velocity in predicting cardiovascular events in normal populations. This is embraced in the 2007 European Society of Hypertension/European Society of Cardiology guidelines in which pu...

In the field of offshore renewable energy, impermeable plates are used as underwater lenses to amplify wave amplitude, and perforated can harness energy a power takeoff device. Within framework linear potential-flow theory, water scattering by horizontal is investigated in present study, both circular elliptical considered. The hypersingular integral equation constructed model interaction betwe...

From research on stratospheric dynamics there has emerged what might prove to be some useful fresh ideas about the problem of water-wave generation by wind. As pointed out in an earlier contribution (1993), water waves can be systematically amplified by two irreversible, ratchet-like mechanisms that depend on spatio-temporal inhomogeneities, such as wind gustiness and wave groupiness. Neither m...

In this paper I will briefly review some applications of nonlinear four-wave-mixing in optical fibers and silicon-nitride waveguides. This includes ultrafast all-optical waveform sampling ‘noiseless’ phase-sensitive amplification which have been demonstrated to enable signal recovery at very low powers.

We study the nondegenerate parametric amplifier for matter waves, implemented by colliding two Bose-Einstein condensates. The coherence of the amplified waves is shown by observing high contrast interference with a reference wave and by reversing the amplification process. Since our experiments also place limits on all known sources of decoherence, we infer that relative number squeezing is mos...

An unexpected transmission loss up to 50% occurs to intense femtosecond pulses propagating along an endlessly single-mode photonic crystal fiber over a length of 1 m. A specific leaky-fiber mode gains amplification along the fiber at the expense of the fundamental fiber mode through stimulated four-wave mixing and Raman scattering, leading to this transmission loss. Bending near the fiber entra...

It is shown that there exists a possibility of amplification of amplitudes of quantum pion modes with low momenta in the late time of chiral phase transition by using the Gaussian wave functional approximation in the O(4) linear sigma model. It is also shown that the amplification occurs in the mechanism of the resonance by forced oscillation as well as the parametric resonance induced by the s...

We demonstrate the time-reversed process of nondegenerate three-wave parametric amplification from three distinct sources in the fully nonlinear regime using a Josephson amplifier. In the reverse process, coherent attenuation, signal and idler beams destructively interfere in the presence of a pump to generate additional pump photons. This effect is observed through the symmetric phase-dependen...

We adopt a three-level scheme for the pump – amplification process in 1.48 m pumped Erbium-Doped Fiber Amplifiers, which reproduces the main experimental features of amplifiers with short and long fiber lengths. Continuous wave amplification in a simplified slab waveguide structure is simulated by means of the scalar Beam Propagation Method, taking into account signal and pump propagation throu...