[Auditory tube dysfunction in children. Part 2]. / Disfunktsiya slukhovoi truby v detskom vozraste. Chast' 2.

The presented literature review examines in detail the methods for diagnosing the auditory tube, the history of development of studies of the Eustachian tube and the treatment of its dysfunction in children. The issue of dysfunction of the auditory tube as one of the causes of the formation of chronic hearing loss in childhood is increasingly being identified because of the rapid development of technologies and methods for examining patients. Aim is to study the multiple etiologic factors of the disease and the need for an integrated approach to the study of this condition.

[Two-year experience in the balloon dilatation treatment of children with persistent auditory tube dysfunction]. / Dvukhletnii opyt lecheniya detei so stoikoi disfunktsiei slukhovoi truby metodom ballonnoi dilatatsii.

OBJECTIVE: Is to study the effectiveness of the of balloon dilatation of the auditory tube in children with persistent dysfunction of the auditory tube. Examination and treatment of 28 children aged 5 to 16 years with persistent dysfunction of the auditory tube was performed. To diagnose and objectify the results of the treatment, taking of complaints and medical history of the patient, examination of ENT organs, endoscopic examination of the nose, nasopharynx and otoendoscopy, functional multispiral computed tomography of the auditory tubes, audiological examination (tympanometry, tonal threshold audiometry) were performed. Treatment included balloon dilatation of the auditory tubes. In 25 (89.3%) children, upon repeated examination after 2, 6, 12 months, the clinical, radiological, and audiological parameters were normal.

[Auditory tube dysfunction in children (literature review, part 2)]. / Disfunktsiya slukhovoi truby v detskom vozraste (obzor literatury, chast' 2).

The presented literature review examines in detail the methods for diagnosing the auditory tube, the history of development of studies of the Eustachian tube and the treatment of its dysfunction in children. The issue of dysfunction of the auditory tube as one of the causes of the formation of chronic hearing loss in childhood is increasingly being identified because of the rapid development of technologies and methods for examining patients. Aim is to study the multiple etiologic factors of the disease and the need for an integrated approach to the study of this condition.

Internal chaotic sea structure and chaos-chaos intermittency in Hamiltonian systems.

In this paper, we study the inhomogeneity of chaotic sea properties far from islands in billiardlike systems and its influence on distributions of particle's return times. A visibly homogeneous chaotic sea at certain parameters has a nontrivial internal structure, in particular, being divided into two chaotic phases with different properties. These phases are not separated by any obstacles, neither in phase nor in configuration spaces, and are partially overlaying. The emergence of a chaotic sea structure may be explained by the existence of remnants of integrable behavior, like sites of regular trajectories of broken islands of stability built into the chaotic sea. In the case of such chaotic seas, we find distributions of return times with two main sites of exponential decay.

[On the issue of treatment of exudative otitis media in children]. / K voprosu o lechenii ékssudativnogo srednego otita v detskom vozraste.

AIM: To increase the effectiveness of treatment of children with catarrhal and secretory stages of exudative otitis media (EOM) through the development of a therapeutic and diagnostic algorithm for the management of children with this condition. MATERIAL AND METHOD: From 2008 to 2017, 346 children (682 ears) aged from 3 to 13 years with exudative otitis media were examined and treated. Two groups of patients were formed: Group 1 (150 children, 298 ears) - with a catarrhal stage of EOM, group 2 (196 children, 384 ears) - with a secretory stage of EOM. Diagnosis and treatment algorithm was created for such patients based on the results of the examination. RESULTS: Depending on the treatment, 3 groups of patients were formed: Group I - 150 children with a catarrhal stage of EOM who received conservative and surgical treatment for upper respiratory tract conditions; Group II - 146 children with an a secretory stage of EOM, who underwent conservative and surgical treatment: myringotomy / installation of a shunt in the eardrum simultaneously with surgical removal of the block of the auditory tube ostium, a course of conservative treatment for children who did not require surgical treatment; Group III - 50 children with a secretory stage of EOM and grade III adenoids, whose parents, contrary to the doctor's advice, refused the proposed myringotomy / installation of a shunt in the eardrum simultaneously with surgical removal of the block of the auditory tube ostium. These children underwent only adenotomy. CONCLUSION: The developed treatment algorithm for children with EOM, depending on the stage of the disease, demonstrated high clinical efficacy and made it possible to achieve stable positive results in 94.7% of cases in patients with the catarrhal stage of ESO and in 84.8% of cases in patients with the secretory stage of ESO, which makes it possible for us to recommend it as an integrated method that improves the quality of treatment for children with EOM.

[Auditory tube dysfunction in children (literature review, part 1)]. / Disfunktsiia slukhovoi truby v detskom vozraste (obzor literatury, chast' 1).

We present the review of the literature on the anatomical and physiological features of the structure of the auditory tube in children, epidemiology, etiology, and the pathogenesis of the formation of auditory tube dysfunction is presented. The first part of the article presents in more detail the structural and functional differences in the Eustachian tube in children, the classification and mechanism of the occurrence of the auditory tube dysfunction in pediatric practice.

[The peculiarities of the clinical picture and treatment of inflammatory ENT diseases in the frequently ill children]. / Osobennosti kliniki i lecheniia vospalitel'nykh zabolevanii LOR-organov u chasto boleiushchikh detei.

The objective of the present study was the analysis of the current state of the problem of the frequently ill children. The authors present the classification of the frequently ill children together with information concerning the influence of various factors on the incidence of pediatric pathologies with special reference to the major pathogenic agents responsible for the formation of the areas of chronic inflammation in the ENT organs of the children. The approaches to the treatment and rehabilitation of the patients belonging to this age group requiring the follow-up monitoring are considered. It is concluded that the comprehensive strategy is needed for providing the adequate care to such children including specific preventive vaccination, well-timed adequate treatment of acute respiratory conditions, rehabilitative therapy with the use of the adaptogenic substances, the development of resistance to the cold and other unfavourable factors, implementation of the relevant socio-medical programs.

Thin structure of the transit time distributions of open billiards.

It is known that typical open billiards distribution of transit times is an exponentially decaying function, possibly with a power-law tail. In the paper we show that on small scales some of such distributions change their appearance. These distributions contain a quasiperiodic thin structure, which carries a significant amount of information about the system. Origin and properties of this structure are discussed.

Analysis of sinusoidally modulated chirped laser pulses by temporally encoded spectral shifting.

We present an analytical formalism elucidating how information is stored in chirped optical probes by describing the effects of sinusoidal temporal modulations on the electric field. We show that the modulations produce spectral sidebands which can be interpreted as temporal sidebands due to the time-wavelength mapping, an effect we call temporally encoded spectral shifting (TESS). A derivation is presented for the case of chirped-pulse spectral interferometry showing how to recover both the amplitude and the periodicity of the modulation from a Fourier transform of the interferogram. The TESS effect, which provides an intuitive picture for interpreting pump-probe experiments with chirped pulses, is illustrated for probing wakefields from a laser-plasma accelerator.

Billiard with a handle.

We consider an open billiard with two holes, connected by a handle. The central billiard is chosen so that its closed form's islands of stability occupy a significant part of the phase space. Holes destroy these islands, which leads to almost all trajectories of the system being interleaved. We also study the unbalanced flow of billiard particles through the handle, which appears only after a small border site of nonspecular reflection is added to the system. With this site our system is rather a ratchet of a different type, since the site does not produce an explicitly acting force or violate the reversibility of trajectories.

High-Flux Femtosecond X-Ray Emission from Controlled Generation of Annular Electron Beams in a Laser Wakefield Accelerator.

Annular quasimonoenergetic electron beams with a mean energy in the range 200-400 MeV and charge on the order of several picocoulombs were generated in a laser wakefield accelerator and subsequently accelerated using a plasma afterburner in a two-stage gas cell. Generation of these beams is associated with injection occurring on the density down ramp between the stages. This well-localized injection produces a bunch of electrons performing coherent betatron oscillations in the wakefield, resulting in a significant increase in the x-ray yield. Annular electron distributions are detected in 40% of shots under optimal conditions. Simultaneous control of the pulse duration and frequency chirp enables optimization of both the energy and the energy spread of the annular beam and boosts the radiant energy per unit charge by almost an order of magnitude. These well-defined annular distributions of electrons are a promising source of high-brightness laser plasma-based x rays.

[Exudative otitis media in the childhood].

This review article was designed to systematize the literature data concerning etiology, pathogenesis, diagnostics and treatment of exudative otitis media (EOM) in the children. The review is focused on the prevailing current tendencies in the approaches to the problems of etiology, diagnostics, and treatment of EOM in the children as exemplified by the publications in the foreign and Russian-speaking literature. The special emphasis is laid on the description of the therapeutic and surgical methods for the management of EOM.

Equation of state of an ideal gas with nonergodic behavior in two connected vessels.

We consider a two-dimensional collisionless ideal gas in the two vessels connected through a small hole. One of them is a well-behaved chaotic billiard, another one is known to be nonergodic. A significant part of the second vessel's phase space is occupied by an island of stability. In the works of Zaslavsky and coauthors, distribution of Poincaré recurrence times in similar systems was considered. We study the gas pressure in the vessels; it is uniform in the first vessel and not uniform in second one. An equation of the gas state in the first vessel is obtained. Despite the very different phase-space structure, behavior of the second vessel is found to be very close to the behavior of a good ergodic billiard but of different volume. The equation of state differs from the ordinary equation of ideal gas state by an amendment to the vessel's volume. Correlation of this amendment with a share of the phase space under remaining intact islands of stability is shown.

Table-top laser-based source of femtosecond, collimated, ultrarelativistic positron beams.

The generation of ultrarelativistic positron beams with short duration (τ(e+) ≃ 30 fs), small divergence (θ(e+) ≃ 3 mrad), and high density (n(e+) ≃ 10(14)-10(15) cm(-3)) from a fully optical setup is reported. The detected positron beam propagates with a high-density electron beam and γ rays of similar spectral shape and peak energy, thus closely resembling the structure of an astrophysical leptonic jet. It is envisaged that this experimental evidence, besides the intrinsic relevance to laser-driven particle acceleration, may open the pathway for the small-scale study of astrophysical leptonic jets in the laboratory.

Scaling high-order harmonic generation from laser-solid interactions to ultrahigh intensity.

Coherent x-ray beams with a subfemtosecond (<10(-15) s) pulse duration will enable measurements of fundamental atomic processes in a completely new regime. High-order harmonic generation (HOHG) using short pulse (<100 fs) infrared lasers focused to intensities surpassing 10(18) W cm(-2) onto a solid density plasma is a promising means of generating such short pulses. Critical to the relativistic oscillating mirror mechanism is the steepness of the plasma density gradient at the reflection point, characterized by a scale length, which can strongly influence the harmonic generation mechanism. It is shown that for intensities in excess of 10(21) W cm(-2) an optimum density ramp scale length exists that balances an increase in efficiency with a growth of parametric plasma wave instabilities. We show that for these higher intensities the optimal scale length is c/ω0, for which a variety of HOHG properties are optimized, including total conversion efficiency, HOHG divergence, and their power law scaling. Particle-in-cell simulations show striking evidence of the HOHG loss mechanism through parametric instabilities and relativistic self-phase modulation, which affect the produced spectra and conversion efficiency.

Scattering by a boundary with complex structure.

The distribution of escape times is usually studied in open billiards theory. In this work, we will concentrate on another important question: The distribution of outgoing rays by exit directions, which we refer to as billiard's indicatrix. It can be obtained analytically and consists of two parts: the symmetric diffuse part and the asymmetric directed part. The criterion for the separation of the indicatrix into these two parts is established. The asymmetry of the directed part of the indicatrix and the influence of the billiard's borders on it is investigated. We also propose a method of the creation of a matte surface model using open billiards with a fully diffuse indicatrix.

Ultrafast electron radiography of magnetic fields in high-intensity laser-solid interactions.

Using electron bunches generated by laser wakefield acceleration as a probe, the temporal evolution of magnetic fields generated by a 4 × 10(19) W/cm(2) ultrashort (30 fs) laser pulse focused on solid density targets is studied experimentally. Magnetic field strengths of order B(0) ~ 10(4) T are observed expanding at close to the speed of light from the interaction point of a high-contrast laser pulse with a 10-µm-thick aluminum foil to a maximum diameter of ~1 mm. The field dynamics are shown to agree with particle-in-cell simulations.

Finite spot effects on radiation pressure acceleration from intense high-contrast laser interactions with thin targets.

Short pulse laser interactions at intensities of 2×10(21) W cm(-2) with ultrahigh contrast (10(-15)) on submicrometer silicon nitride foils were studied experimentally by using linear and circular polarizations at normal incidence. It was observed that, as the target decreases in thickness, electron heating by the laser begins to occur for circular polarization leading to target normal sheath acceleration of contaminant ions, while at thicker targets no acceleration or electron heating is observed. For linear polarization, all targets showed exponential energy spreads with similar electron temperatures. Particle-in-cell simulations demonstrate that the heating is due to the rapid deformation of the target that occurs early in the interaction. These experiments demonstrate that finite spot size effects can severely restrict the regime suitable for radiation pressure acceleration.

Control of energy spread and dark current in proton and ion beams generated in high-contrast laser solid interactions.

By using temporal pulse shaping of high-contrast, short pulse laser interactions with solid density targets at intensities of 2 × 10(21) W cm(-2) at a 45° incident angle, we show that it is possible to reproducibly generate quasimonoenergetic proton and ion energy spectra. The presence of a short pulse prepulse 33 ps prior to the main pulse produced proton spectra with an energy spread between 25% and 60% (ΔE/E) with energy of several MeV, with light ions becoming quasimonoenergetic for 50 nm targets. When the prepulse was removed, the energy spectra was broad. Numerical simulations suggest that expansion of the rear-side contaminant layer allowed for density conditions that prevented the protons from being screened from the sheath field, thus providing a low energy cutoff in the observed spectra normal to the target surface.