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Abstract The nonlinear interaction of copropagating optical solitons enables a large variety of intriguing bound-states of light. We here investigate the interaction dynamics of two initially superimposed fundamental solitons at distinctly different frequencies. Both pulses are located in distinct domains of anomalous dispersion, separated by an interjacent domain of normal dispersion, so that group velocity matching can be achieved despite a vast frequency gap. We demonstrate the existence of two regions with different dynamical behavior. For small velocity mismatch we observe a domain in which a single heteronuclear pulse compound is formed, which is distinct from the usual concept of soliton molecules. The binding mechanism is realized by the mutual cross phase modulation of the interacting pulses. For large velocity mismatch both pulses escape their mutual binding and move away from each other. The crossover phase between these two cases exhibits two localized states with different velocity, consisting of a strong trapping pulse and weak trapped pulse. We detail a simplified theoretical approach which accurately estimates the parameter range in which compound states are formed. This trapping-to-escape transition allows to study the limits of pulse-bonding as a fundamental phenomenon in nonlinear optics, opening up new perspectives for the all-optical manipulation of light by light.

Handwriting style is an important aspect affecting the quality of handwriting. Adhering to one style is crucial for languages that follow cursive orthography and possess multiple handwriting styles, such as Arabic. The majority of available studies analyze Arabic handwriting style from static documents, focusing only on pure styles. In this study, we analyze handwriting samples with mixed styles, pure styles (Ruq'ah and Naskh), and samples without a specific style from dynamic features of the stylus and hand kinematics. We propose a model for classifying handwritten samples into four classes based on adherence to style. The stylus and hand kinematics data were collected from 50 participants who were writing an Arabic text containing all 28 letters and covering most Arabic orthography. The parameter search was conducted to find the best hyperparameters for the model, the optimal sliding window length, and the overlap. The proposed model for style classification achieves an accuracy of 88%. The explainability analysis with Shapley values revealed that hand speed, pressure, and pen slant are among the top 12 important features, with other features contributing nearly equally to style classification. Finally, we explore which features are important for Arabic handwriting style detection. [ABSTRACT FROM AUTHOR]

Abstract We study theoretically a possibility of creation and ultrafast control (erasing, spatial frequency multiplication) of population density gratings in a multi-level resonant medium having a resonance transition frequency in the THz range. These gratings are produced by subcycle THz pulses coherently interacting with a nonlinear medium, without any need for pulses to overlap, thereby utilizing an indirect pulse interaction via an induced coherent polarization grating. High values of dipole moments of the transitions in the THz range facilitate low field strength of the needed THz excitation. Our results clearly show this possibility in multi-level resonant media. Our theoretical approach is based on an approximate analytical solution of time-dependent Schrödinger equation (TDSE) using perturbation theory. Remarkably, as we show here, quasi-unipolar subcycle pulses allow more efficient excitation of higher quantum levels, leading to gratings with a stronger modulation depth. Numerical simulations, performed for THz resonances of the $$H_20$$ H 2 0 molecule using Bloch equations for density matrix elements, are in agreement with analytical results in the perturbative regime. In the strong-field non-perturbative regime, the spatial shape of the gratings becomes non-harmonic. A possibility of THz radiation control using such gratings is discussed. The predicted phenomena open novel avenues in THz spectroscopy of molecules with unipolar and quasi-unipolar THz light bursts and allow for better control of ultra-short THz pulses.

Abstract Here we consider coherent mode-locking (CML) regimes in single-section cavity lasers, taking place for pulse durations less than atomic population and phase relaxation times, which arise due to coherent Rabi oscillations of the atomic inversion. Typically, CML is introduced for lasers with two sections, the gain and absorber ones. Here we show that, for certain combination of the cavity length and relaxation parameters, a very stable CML in a laser, containing only gain section, may arise. The mode-locking is unconditionally self-starting and appears due to balance of intra-pulse de-excitation and slow interpulse-scale pump-induced relaxation processes. We also discuss the scaling of the system to shorter pulse durations, showing a possibility of mode-locking for few-cycle pulses.

M.M. Bikbov, O.I. Orenburkina, A.E. Babushkin, A.M. Tulyakova Ufa Research Institute of Eye Diseases, Ufa, Russian Federation Residual astigmatism or ametropia are relatively common after phacoemulsification. This entity is accounted for by inaccurate intraocular lens (IOL) power calculation or improper preoperative examination. As a result, target refraction is not achieved. Spectacle correction of astigmatism in pseudophakia has several drawbacks and is often poorly tolerated, leaving patients unsatisfied with surgical outcomes. This paper reviews state-of-the-art surgical techniques for correcting residual astigmatism after cataract surgery. These include laser (photorefractive keratectomy/PRK and laser in situ keratomileusis/LASIK), Femto laser (arcuate keratotomy), and intraocular (add-on toric IOL implantation) procedures. The authors address published data on the pros and cons of these interventions. These techniques empower surgical correction of astigmatism and provide the best possible vision for patients. Finally, this paper discusses postoperative management using tear substitutes. Keywords: phacoemulsification, residual astigmatism, PRK, LASIK, femtosecond arcuate incisions, add-on toric IOLs. For citation: Bikbov M.M., Orenburkina O.I., Babushkin A.E., Tulyakova A.M. Current approaches to residual astigmatism correction after phacoemulsification. Russian Journal of Clinical Ophthalmology. 2022;22(1):51–57 (in Russ.). DOI: 10.32364/2311-7729-2022-22-1-51-57.

This article reviews all available information on the species composition, current distribution, and origins of the neobiotic (non-indigenous and restoring the lost range) freshwater mollusks in Siberia. An extensive literary search has been carried out, and virtually all existing publications of recent decades on the findings of freshwater mollusk species new to Siberia were taken into account. We examined extensive malacological collections of some of Russia’s and Kazakhstan’s scientific organizations. The core of the examined material is our own observations and collections made in various parts of Siberia and adjacent areas. An annotated checklist of neobiotic species of mollusks reliably recorded in Siberia is presented, and probable mechanisms and “corridors” of infiltration of these species into the region are discussed. Most of the discovered snail species belong to a group popular among aquarists, and their source of introduction is obvious. Another large portion of species infiltrate into the region with the development of fish farming. A classification of species of neobiotic freshwater mollusks of Siberia was proposed and a forecast was made for changes in the Siberian freshwater malacofauna for the coming decades. In our opinion, at present it is possible to accept the newest stage in the genesis of the freshwater malacofauna of Siberia, occurring in conditions specific to the Anthropocene.

The taxonomic position and phylogenetic affinities of the endemic North Asian genus Kolhymamnicola Starobogatov and Budnikova, 1976 (Gastropoda: Amnicolidae) remain unknown. To resolve this, we studied key morpho-anatomical characteristics of Kolhymamnicola snails and performed a molecular phylogenetic analysis based on sequences of COI mtDNA, 16S rRNA, and 18S rRNA genes. In terms of protoconch microsculpture, operculum, radular teeth, and gill complex morphology, Kolhymamnicola snails do not differ significantly from the North American genera Amnicola Gould and Haldeman, 1840 and Taylorconcha Hershler et al., 1994, and the European genus Marstoniopsis van Regteren Altena 1936. The bifid penis found in Kolhymamnicola is similar to that in the genus Marstoniopsis. The female reproductive anatomy has some features shared by Kolhymamnicola and Taylorconcha (absence of bursa copulatrix, single seminal receptacle in rs2′ position, and ventral channel). The molecular analysis has revealed Taylorconcha as the closest relative to Kolhymamnicola; the COI-based genetic distance between them amounted to 0.113. We discuss the possible time of divergence of these two genera, as well as of European Marstoniopsis and the Baikal Lake endemic family Baicaliidae. The last common ancestor of these groups was widely distributed in Miocene–Pliocene in the Holarctic waterbodies. Recent Kolhymamnicola snails are distributed in Northern Asia, including lakes of the Baikal rift zone. We rank the Baicaliidae as a family rather than a subfamily of Amnicolidae based on their distinct, unique morpho-anatomical characteristics and highly supported separate position on the molecular tree. The tribe Erhaiini Davis and Kuo, 1985 is elevated to the rank of the family, with 3–4 recent genera included. The family Palaeobaicaliidae Sitnikova et Vinarski fam. nov. is established to embrace the Cretaceous North Asian gastropods conchologically similar to the recent Baicaliidae and Pyrgulidae.

M.M. Bikbov, O.I. Orenburkina, A.E. Babushkin, A.A. Fakhretdinova Ufa Research Institute of Eye Diseases, Ufa, Russian Federation Eye disorders have a special place in diabetes since visual impairment has a significant effect on the quality of life. Therefore, determining risk factors and prognostic criteria for disease course are essential for developing strategies for early prevention of diabetic retinopathy (DR). This paper addresses studies on various aspects of DR in patients with myopia. It was demonstrated that DR arises, develops, and progresses in different ways under various axial lengths (AL). Thus, many authors report that DR barely occurs in high myopia. Some of them account for this phenomenon for poor blood circulation in a long myopic eye. Others refer to a significantly lower vascular endothelial growth factor (VEGF) concentration in longer eyes or eyes with myopic refraction. The third authors argue a focal disintegration of retinal pigment epithelium to eliminate metabolic end products through the choroid and sclera. As a result, neither acidosis nor venous congestion develops, and end othelial barrier function remains unaffected Keywords: diabetic retinopathy, myopia, axial length, vascular endothelial growth factor, emmetropia, hyperopia, diabetes. For citation: Bikbov M.M., Orenburkina O.I., Babushkin A.E., Fakhretdinova A.A. Effects of refraction and axial length on the development and progression of diabetic retinopathy. Russian Journal of Clinical Ophthalmology. 2021;21(4):205–209 (in Russ.). DOI: 10.32364/2311-7729-2021-21-4-205-209.

The article is devoted to the analysis of the results of studying cultivars of indian pea (Lathyrus sativus L.) under the conditions of the Nizhnevolzhsky (Saratov) and West Siberian (Omsk) regions of the Russian Federation. Indianpea serves a variety of purposes: compound feed, forage, an alternative source of protein for the population, due to the high protein content in seeds and mature leaves. In the arid conditions of the Russian Federation, the indianpea is able to occupy its own agronomic niche and become an additional source of replenishing cheap protein and improving the quality of the forage base. In this connection, a study of four varieties of the indianpea breeding of the 1Russian Research Institute for Sorghum and Maize "Rossorgo" (Racheika, Zhemchuzhina, Elena, Mramornya) was carried out according to economically valuable parameters, data were obtained on the biochemical composition of seeds and green mass, and an assessment was carried out on bioenergetic parameters. The influence of factors “A”, “B” and their interaction “AB” on the manifestation of signs was noted. According to the results of a two-factor analysis of variance, it follows that the factor of growing conditions (A) has the greatest influence on the seed yield index – 64.2%, and the yield of green mass - the genotype factor (B) - 59.5%. The study revealed a high protein content in seeds (28.3-31.1%) and green mass (21.0-26.3%). Determination of the biochemical composition makes it possible to evaluate varieties in terms of gross energy output with seeds and green mass. According to the parameters of the bioenergetic efficiency of seeds, the best indicators were found in the varieties Elena and Zhemchuzhina. Variety Elena was distinguished by the highest content of total energy in the green mass of 48.0-94.8 GJ/ha. Variety Zhemchuzhina was characterized by the maximum content of total energy in the grown seed crop – 26.0-29.3 GJ/ha, the largest increment in gross energy – 12.6 GJ/ha and the highest energy efficiency coefficient of all four varieties – 1.94.

The article presents the results of studying the main elements of seed productivity in 15 breeding lines of F6-7 generations of lentils obtained from interspecific crossings of varieties Aida (Russia), Vekhovskaya (Russia), Vostochnaya (Russia) and Shyraily (Kazakhstan). The purpose of the study is to research the phenotypic variability of lentil breeding lines according to the elements of the crop structure and select valuable genotypes as sources of productivity to create varieties adapted to the conditions of the region. Phenotyping of the breeding material was carried out in the field and laboratory conditions in 2020-2022 at the training and experimental field of the Omsk State Agrarian University named after P.A. Stolypin. During the study period, very dry climatic conditions developed in 2020 (HTC = 0.62) and 2021 (HTC = 0.68), slightly dry - in 2022 (hydrothermal coefficient = 1.02). The ecological plasticity of the breeding lines was assessed by the value of the intensity and stability indicators of the stability index.The ecological plasticity of the breeding lines was assessed by the value of the intensity and stability indicators of the stability index. As a result, it was found that 11 genotypes belong to the group of varieties of intensive type, 4 - semi-intensive. Of the 15 lines, only 11 show stable seed productivity in all weather conditions, and 4 are characterized as unstable. Based on the research, valuable genotypes were selected that will be used as sources of seed productivity in further breeding and the creation of new adapted, high-yielding varieties of lentils in the region.

The article describes the global trend of industrial transition to the concept of “Industry 4.0” and the prerequisites for its influence on the field of industry standardization, in particular construction. The need to reorganize the current standardization system, which does not keep up with the pace of digital development of production, is outlined. The authors analyzed the modern standard-setting system in the construction industry, identified its main problems, which consist in a large volume of requirements for construction products and processes, an outdated approach to standardization in general, as well as a weak and ineffective existing standardization system and the difficulty of harmonizing Russian national standards with international standards. The described problems are relevant today, since right now the standardization system in the Russian construction industry is experiencing a new round of development, the abandonment of the prescriptive and target method of construction regulation and the transition to the parametric method. The study proved that the use of such modern technologies as digital standards (SMART standards) can solve the identified problems in the field of standardization, which in turn will affect the quality and efficiency of the regulatory system in construction.