The Akhmediev breather (AB) solution of the nonlinear Schrödinger equation (NLSE) shows that maximum crest height modulated wave trains reaches triple initial amplitude as a consequence long-term evolution. Several fully numerical studies have indicated amplification can exceed 3, but its physical mechanism has not been clarified. This study spectral broadening, bound-wave production, and phase...

A quantum model for Josephson-based metamaterials working in the Three-Wave Mixing (3WM) and Four-Wave (4WM) regimes at single-photon level is presented. The transmission line taken into account, namely Traveling Wave Josephson Parametric Amplifier (TWJPA), a bipole composed by chain of rf-SQUIDs which can be biased DC current or magnetic field order to activate 3WM 4WM nonlinearities. exploits...

The possibility of compensating absorption in negative-index metamaterials (NIMs) doped by resonant nonlinear-optical centers is shown. The role of quantum interference and the extraordinary properties of four-wave parametric amplification of counterpropagating electromagnetic waves in NIMs are discussed.

Blood pressure is one of the cardinal risk factors for atherosclerosis and cardiovascular diseases. Systolic and diastolic blood pressures are measured at the level of the brachial artery, positioned at a midthoracic level with an adequately sized cuff and bladder. Treatment of arterial hypertension with lifestyle and drugs has become one of the cornerstones of contemporary cardiology. Subjects...

Elevated heart rate (HR) and pulse pressure (PP) have a cumulative effect on cardiovascular risk, with the exception of HR >/=100 bpm. How an increase in HR may influence the PP level has never been investigated. In 11 patients with pacemaker monitoring, aortic (pulse-wave analysis) and digital (photoplethysmographic device) blood pressure were measured at 3 different levels of HR, together wit...

The operation of the mammalian cochlea relies on a mechanical traveling wave that is actively boosted by electromechanical forces in sensory outer hair cells (OHCs). This active cochlear amplifier produces the impressive sensitivity and frequency resolution of mammalian hearing. The cochlear amplifier has inspired scientists since its discovery in the 1970s, and is still not well understood. To...

The goal of this project is to develop InAIAs/InGaAs heterostructure field-effect transistors suitable for millimeter-wave high-power applications. The suitability of this material system for low-noise amplification is now unquestionable. Obtaining a high breakdown voltage is, however, still rather difficult, and it usually comes with severe trade offs. This fact seriously limits the suitabilit...