The nervous system of Hydra, a freshwater cnidaria, occurs as dispersed, or diffuse, nerve net throughout the animal. It is widely accepted that in a diffuse nervous system an external stimulus is conducted in all directions over the net. Here I report observations that hydra tentacles respond to feeding and wounding stimuli in a unidirectional manner. Upon contact of a tentacle with a brine sh...

Abstract: Inclination of the bias magnetization in a magnetooptic waveguide yields both nonreciprocal phase shifts and polarization conversion. This enables the design of unidirectional polarization converters, i.e. waveguides that switch between orthogonal polarizations for one direction of light propagation, but keep the polarization state for light propagating in the opposite direction. Simu...

We propose a class of spectral singularities emerging from the coincidence of two independent singularities with highly directional responses. These spectral singularities result from resonance trapping induced by the interplay between parity-time symmetry and Fano resonances. At these singularities, while the system is reciprocal in terms of a finite transmission, a simultaneous infinite refle...

We previously showed that a premature stimulus can significantly alter vulnerability to arrhythmias by modulating spatial gradients of ventricular repolarization (ie, modulated dispersion). However, it is not clear if such changes in arrhythmia vulnerability can be attributed to the formation of an electrophysiological substrate for unidirectional block and what the potential role is of tissue ...

A computer model of a ring-shaped, one-dimensional cardiac fiber was used for examination of responses of propagation to premature stimuli applied under different degrees of both cell-to-cell coupling and membrane excitability. Results demonstrated the importance of cellular uncoupling in the genesis of unidirectional block and reentry. Propagation of excitation itself created a certain degree ...

This paper introduces a versatile control scheme for unidirectional ac–dc boost converters using fuzzy logic controller for the purpose of mitigating grid power quality. Since most power factor correction circuits available in the commercial market utilize unidirectional ac– dc boost converter topologies, this is an almost nocost solution for compensating harmonic current and reactive power in ...