Bright and dark solitons in the systems with strong light-matter coupling: Exact solutions and numerical simulations.

We theoretically study bright and dark solitons in an experimentally relevant hybrid system characterized by strong light-matter coupling. We find that the corresponding two-component model supports a variety of coexisting moving solitons including bright solitons on zero and nonzero background and dark-gray and gray-gray solitons. The solutions are found in the analytical form by reducing the two-component problem to a single stationary equation with cubic-quintic nonlinearity. All found solutions coexist under the same set of the model parameters, but, in a properly defined linear limit, approach different branches of the polariton dispersion relation for linear waves. Bright solitons with zero background feature an oscillatory-instability threshold which can be associated with a resonance between the edges of the continuous spectrum branches. "Half-topological" dark-gray and nontopological gray-gray solitons are stable in wide parametric ranges below the modulational instability threshold, while bright solitons on the constant-amplitude pedestal are unstable.

PROJECTING OF COMPLEX HEALTH TRAINING FOR MATURE MEN WITH METABOLIC SYNDROME.

OBJECTIVE: The aim: To identify risk factors for metabolic syndrome; to model, justify and experimentally test the effectiveness of a program of complex health training for mature men with MS. PATIENTS AND METHODS: Materials and methods: Theoretical - analysis, generalization, pedagogical observation, modelling; empirical - methods of implementation of the results in practice (pedagogical experiment involving 50 mature menwho had no contraindications to training), methods of monitoring and measuring of physical evolvement, body systems functional status (samples: Rufier, Stange), general performance level (Harvard step test), medical indicators (blood glucose level, arterial tension). RESULTS: Results: A complex organized health training program (graduated, systematic, all-round motor activity managed by an instructor) showed better results (24,5 %) compared an independent health training system(15,2 %). Both types of activity contributed to weight loss(CG2 - 10,1 %; EG2 - 15,5 %) and reduction of body parts overall size; functional improvement of cardiovascular and respiratory systems of the male body, in particular in the indicators of the Stange test (CG2 - 29,8 %,EG2 - 33,9 %), Ruffier index (CG2 - 5,8 %, EG2 - 23,0 %) and step test (CG2 - 15,8 %, EG2 - 26,9 %); positive changes in blood glucose levels (CG2 - 20,7 %, EG2 - 31,5 %) andarterial tension (CG2 - 6,2 %, EG2 - 9,8 %); development of different muscle groupsstrength endurance. CONCLUSION: Сonclusions: Positive changes according to the studied indicators show the decrease in risk factors for mature men metabolic syndrome and thereby preventingcomplications.

Spontaneous symmetry breaking and the dynamics of three interacting nonlinear optical resonators with gain and loss.

The dynamics of two active nonlinear resonators coupled to a linear resonator is studied theoretically. Possible stationary states and their dynamical stability are considered in detail. Spontaneous symmetry breaking is found and it is shown that this bifurcation results in the formation of asymmetric states. It is also found that the oscillating states can occur in the system in a certain range of parameters. The results of the analysis of the stationary states are confirmed by direct numerical simulations. The possibility of switching between different states is also demonstrated by numerical experiments.

Interactions of the solitons in periodic driven-dissipative systems supporting quasibound states in the continuum.

The paper is devoted to the dynamics of dissipative gap solitons in the periodically corrugated optical waveguides whose spectrum of linear excitations contains a mode that can be referred to as a quasi-bound state in the continuum. These systems can support a large variety of stable bright and dark dissipative solitons that can interact with each other and with the inhomogeneities of the pump. One of the focus points of this work is the influence of slow variations of the pump on the behavior of the solitons. It is shown that for the fixed sets of parameters the effect of pump inhomogeneities on the solitons is not the same for the solitons of different kinds. The second main goal of the paper is systematic study of the interaction between the solitons of the same or different kinds. It is demonstrated that various scenarios of intersoliton interactions can occur: The solitons can repulse each other or get attracted. In the latter case, the solitons can annihilate, fuse in a single soliton, or form a new bound state depending on the kinds of the interacting solitons and on the system parameters.

CURRENT ASPECTS OF DELIVERY IN HEALTHY WOMEN IN ACCORDANCE WITH THE DATA OF RETROSPECTIVE ANALYSIS.

OBJECTIVE: The aim: to study the current aspects of the course of labor in healthy women using retrospective indicators. PATIENTS AND METHODS: Materials and methods: To study this topic, an analysis of 1,078 births on the basis of the maternity ward for pregnant women with obstetric pathology of the State Institution «IPAG. acad. O.M. Lukyanova National Academy of Medical Sciences of Ukraine¼. It was found that among all births, the share of first-borns was 602 (55.8 %) women, of whom 451 (41.8 %) were pregnant for the first time, and only 86 (8 %) were healthy pregnant women. RESULTS: Results: It was found that among 86 births the frequency of physiological births was 64%, of which in 47.7% of cases the birth was complicated, and pathological - 36%. The most common complications during childbirth were: premature rupture of membranes (PRPO), episio- and perineotomy, trauma to the birth canal. The main causes of pathological childbirth: abnormalities of labor, fetal distress, defect of the placenta and membranes, clinically narrow pelvis, malposition of the fetus and early postpartum hemorrhage. All children were born alive. It should be noted that all births where the Apgar score was ≤ 6 had no partner support, and the women themselves did not receive any preparation for childbirth. CONCLUSION: Conclusions: According to our data, in almost healthy women who gave birth for the first time and had no perinatal loss in the anamnesis, did not undergo prenatal training and did not have partner support during childbirth, the number of complications during childbirth is increasing. Therefore, this group of healthy pregnant women needs more detailed study and analysis, development of prenatal training algorithms to improve perinatal indicators.

Ultrafast-nonlinear ultraviolet pulse modulation in an AlInGaN polariton waveguide operating up to room temperature.

Ultrafast nonlinear photonics enables a host of applications in advanced on-chip spectroscopy and information processing. These rely on a strong intensity dependent (nonlinear) refractive index capable of modulating optical pulses on sub-picosecond timescales and on length scales suitable for integrated photonics. Currently there is no platform that can provide this for the UV spectral range where broadband spectra generated by nonlinear modulation can pave the way to new on-chip ultrafast (bio-) chemical spectroscopy devices. We demonstrate the giant nonlinearity of UV hybrid light-matter states (exciton-polaritons) up to room temperature in an AlInGaN waveguide. We experimentally measure ultrafast nonlinear spectral broadening of UV pulses in a compact 100 µm long device and deduce a nonlinearity 1000 times that in common UV nonlinear materials and comparable to non-UV polariton devices. Our demonstration promises to underpin a new generation of integrated UV nonlinear light sources for advanced spectroscopy and measurement.

Dissipative switching waves and solitons in the systems with spontaneously broken symmetry.

The paper addresses the bistability caused by spontaneous symmetry breaking bifurcation in a one-dimensional periodically corrugated nonlinear waveguide pumped by coherent light at normal incidence. The formation and the stability of the switching waves connecting the states of different symmetries are studied numerically. It is shown that the switching waves can form stable resting and moving bound states (dissipative solitons). The protocols of the creation of the discussed nonlinear localized waves are suggested and verified by numerical simulations.

Propagative Oscillations in Codirectional Polariton Waveguide Couplers.

We report on novel exciton-polariton routing devices created to study and purposely guide light-matter particles in their condensate phase. In a codirectional coupling device, two waveguides are connected by a partially etched section that facilitates tunable coupling of the adjacent channels. This evanescent coupling of the two macroscopic wave functions in each waveguide reveals itself in real space oscillations of the condensate. This Josephson-like oscillation has only been observed in coupled polariton traps so far. Here, we report on a similar coupling behavior in a controllable, propagative waveguide-based design. By controlling the gap width, channel length, or propagation energy, the exit port of the polariton flow can be chosen. This codirectional polariton device is a passive and scalable coupler element that can serve in compact, next generation logic architectures.

Spontaneous symmetry breaking of nonlinear states in optical cavities with radiative losses.

The dynamics of one-dimensional periodically modulated optical cavities are studied in the framework of coupled counterpropagating wave approximation. It is shown that in these systems, a spontaneous symmetry breaking bifurcation can occur, resulting in the formation of the dynamically stable asymmetric states with nonzero energy flux. Bright cavity solitons nestling on the spatially uniform backgrounds with broken symmetry are found and investigated in detail. One of the distinguishing features of the solitons on the asymmetric background is that they can exist at the pump powers much less than those needed for the formation of the solitons on the symmetric backgrounds.

Dynamics of localized dissipative structures in a generalized Lugiato-Lefever model with negative quartic group-velocity dispersion.

We study localized dissipative structures in a generalized Lugiato-Lefever equation, exhibiting normal group-velocity dispersion and anomalous quartic group-velocity dispersion. In the conservative system, this parameter-regime has proven to enable generalized dispersion Kerr solitons. Here, we demonstrate via numerical simulations that our dissipative system also exhibits equivalent localized states, including special molecule-like two-color bound states recently reported. We investigate their generation, characterize the observed steady-state solution, and analyze their propagation dynamics under perturbations.

Nonlinear Control of Electromagnetic Topological Edge States.

Topological photonics has emerged recently as a smart approach for realizing robust optical circuitry, and the study of nonlinear effects is expected to open the door for tunability of photonic topological states. Here we realize experimentally nonlinearity-induced spectral tuning of electromagnetic topological edge states in arrays of coupled nonlinear resonators in the pump-probe regime. When nonlinearity is weak, we observe that the frequencies of the resonators exhibit spectral shifts concentrated mainly at the edge mode and affecting only weakly the bulk modes. For a strong pumping, we describe several scenarios of the transformation of the edge states and their hybridization with bulk modes, and also predict a parametrically driven transition from topological stationary to unstable dynamic regimes.

Nonlinearity-induced localization in a periodically driven semidiscrete system.

We demonstrate that nonlinearity plays a constructive role in supporting the robustness of dynamical localization in a system which is discrete in one dimension and continuous in the orthogonal one. In the linear regime, time-periodic modulation of the gradient strength along the discrete axis leads to the usual rapid spread of an initially confined wave packet. Addition of the cubic nonlinearity makes the dynamics drastically different, inducing robust localization of moving wave packets. Similar nonlinearity-induced effects are also produced in the presence of a combination of static and oscillating linear potentials. The predicted dynamical localization in the nonlinear medium can be realized in photonic lattices and Bose-Einstein condensates.

Bloch oscillations sustained by nonlinearity.

We demonstrate that nonlinearity may play a constructive role in supporting Bloch oscillations in a model which is discrete, in one dimension and continuous in the orthogonal one. The model can be experimentally realized in several fields of physics such as optics and Bose-Einstein condensates. We demonstrate that designing an optimal relation between the nonlinearity and the linear gradient strength provides extremely long-lived Bloch oscillations with little degradation. Such robust oscillations can be observed for a broad range of parameters and even for moderate nonlinearities and large enough values of linear potential. We also present an approximate analytical description of the wave packet's evolution featuring a hybrid Bloch oscillating wave-soliton behavior that excellently corresponds to the direct numerical simulations.

[THE PREDICTIVE SIGNIFICANCE OF A MALLAMPATI SAMSOON & YOUNG SCORE AT OPERATIONS IN NOSE AND NASOPHARYNX AT CHILDREN].

BACKGROUND: The difficult airways at children happen rarely, but can lead to serious complications. MATERIALS AND METHODS: Results of studying of sensitivity, specificity and predictive importance of a scale of Mallampati at 379 children aged from 3 till 17 years (ASA physical status I-II), who underwent surgery in the nasal cavity and nasopharynx, are presented in this article. Depending on result of Mallampati's score children have been distributed on 2 groups. In the first group 20 children had predictions of the difficult intubation of a trachea, 19 of them had the 3rd degree by Mallampati, 1 child had the 4th degree by Mallampati. In the second group 370 children had 1-2 class on Mallampati scale. During direct laryngoscopy, 8 patients had 3 degree on Cormack & Lehane and the 382 patients had 1-2 degree on Cormack & Lehane. The degree of the laryngoscopy's difficulty determine by results of the Mallampati Samsoon & Young. RESULTS AND CONCLUSION: It is found out that sensitivity (Se) of a scale of Mallampati in modification of Samsoon & Young at children at operations in the nasal cavity and nasopharynx of 50%, specificity (Sp) of 96%, the positive predictive value (+VP) of 20%, the negative predictive value (-VP) of 99%.

Self-adjusted all-dielectric metasurfaces for deep ultraviolet femtosecond pulse generation.

The advantage of metasurfaces and nanostructures with a high nonlinear response is that they do not require phase matching, and the generated pulses are short in the time domain without additional pulse compression. However, the fabrication of large-scale planar structures by lithography-based methods is expensive, time consuming, and requires complicated preliminary simulations to obtain the most optimized geometry. Here, we propose a novel strategy for the self-assembled fabrication of large-scale resonant metasurfaces, where incident femtosecond laser pulses adjust the initial silicon films via specific surface deformation to be as resonant as possible for a given wavelength. The self-adjusting approach eliminates the necessity of multistep lithography and designing, because interference between the incident and the scattered parts of each laser pulse "imprints" resonant field distribution within the film. The self-adjusted metasurfaces demonstrate a high damage threshold (≈1012 W cm-2) and efficient frequency conversion from near-IR to deep UV. The conversion efficiency is up to 30-fold higher compared with nonresonant smooth Si films. The resulting metasurfaces allow for the generation of UV femtosecond laser pulses at a wavelength of 270 nm with a high peak and average power (≈105 W and ≈1.5 µW, respectively). The results pave the way to the creation of ultrathin nonlinear metadevices working at high laser intensities for efficient deep UV generation at the nanoscale.

Motion of dissipative optical fronts under the action of an oscillating pump.

The dynamics of domain walls in optical bistable systems with pump and loss is considered. It is shown that an oscillating component of the pump affects the average drift velocity of the domain walls. The cases of harmonic and biharmonic pumps are considered. It is demonstrated that in the case of biharmonic pulse the velocity of the domain wall can be controlled by the mutual phase of the harmonics. The analogy between this phenomenon and the ratchet effect is drawn. Synchronization of the moving domain walls by the oscillating pump in discrete systems is studied and discussed.

Emulation of Fabry-Perot and Bragg resonators with temporal optical solitons.

The scattering of weak dispersive waves (DWs) on several equally spaced temporal solitons is studied. It is shown by systematic numerical simulations that the reflection of the DWs from the soliton trains strongly depends on the distance between the solitons. The dependence of the reflection and transmission coefficients on the inter-soliton distance and the frequency of the incident waves are studied in detail, revealing fascinating quasi-periodic behavior. The analogy between the observed nonlinear phenomena in the temporal domain and the usual Fabry-Perot and Bragg resonators is discussed.

Interaction of high-order solitons with external dispersive waves.

The effect of mutual interaction between second-order soliton and dispersive waves (DWs) is investigated. It is predicted analytically and confirmed numerically that DWs (both transmitted and reflected components) become polychromatic after interaction with the soliton. Collision with DWs of considerable intensity can lead to acceleration/deceleration and central frequency shift of the soliton, while still preserving the soliton's oscillating structure. Two second-order solitons with resonant DWs trapped between them can form an effective solitonic cavity with "flat" or "concave mirrors," depending on the intensity of the input.

Weak and strong interactions between dark solitons and dispersive waves.

The effect of mutual interactions between dark solitons and dispersive waves is investigated numerically and analytically. The condition of the resonant scattering of dispersive waves on dark solitons is derived and compared against the results of the numerical simulations. It is shown that the interaction with intense dispersive waves affects the dynamics of the solitons by accelerating, decelerating, or destroying them. It is also demonstrated that two dark solitons can form a cavity for dispersive waves bouncing between the two dark solitons. The differences of the resonant scattering of the dispersive waves on dark and bright solitons are discussed. In particular, we demonstrate that two dark solitons and a dispersive wave bouncing in between them create a solitonic cavity with convex "mirrors," unlike the concave "mirror" in the case of bright solitons.

Ultra-low-power hybrid light-matter solitons.

New functionalities in nonlinear optics will require systems with giant optical nonlinearity as well as compatibility with photonic circuit fabrication techniques. Here we introduce a platform based on strong light-matter coupling between waveguide photons and quantum-well excitons. On a sub-millimetre length scale we generate picosecond bright temporal solitons at a pulse energy of only 0.5 pJ. From this we deduce a nonlinear refractive index three orders of magnitude larger than in any other ultrafast system. We study both temporal and spatio-temporal nonlinear effects and observe dark-bright spatio-temporal polariton solitons. Theoretical modelling of soliton formation in the strongly coupled system confirms the experimental observations. These results show the promise of our system as a high speed, low power, integrated platform for physics and devices based on strong interactions between photons.