Raman-Kerr frequency combs in microresonators with normal dispersion.

We generalize the coupled mode formalism to study the generation of frequency combs in microresonators with simultaneous Raman and Kerr nonlinearities and investigate an impact of the former on the formation of frequency combs and dynamics of platicons in the regime of the normal group velocity dispersion. We demonstrate that the Raman effect initiates generation of sidebands, which cascade further in four-wave mixing and reshape into the Raman-Kerr frequency combs. We reveal that the Raman scattering induces a strong instability of the platicon pulses associated with the Kerr effect and normal dispersion.

Harmonization of chaos into a soliton in Kerr frequency combs.

Dissipative Kerr solitons have paved the way to broadband and fully coherent optical frequency combs in microresonators. Here, we demonstrate numerically that slow frequency tuning of the pump laser in conjunction with phase or amplitude modulation corresponding to the free spectral range of the microresonator, provides reliable convergence of an initially excited chaotic comb state to a single dissipative Kerr soliton (DKS) state. The efficiency of this approach depends on both frequency tuning speed and modulation depth.

True navigation in migrating gulls requires intact olfactory nerves.

During migratory journeys, birds may become displaced from their normal migratory route. Experimental evidence has shown that adult birds can correct for such displacements and return to their goal. However, the nature of the cues used by migratory birds to perform long distance navigation is still debated.

[Problems in medical waste handling in penitentiaries].

The urgency of the problems associated with epidemiologically hazardous waste resulting in the penitentiary system stems from that about half of the convicts seeking medical advice suffer from social diseases. In this connection the authors propose to combine Classes B and C medical waste and to consider them to be Class C (extremely hazardous substances) and to refer Class A waste to as Class B (hazardous substances). Classes A, B, and C waste results in the penitentiaries with patients with active tuberculosis should be regarded as Class C (extremely hazardous substances).