Investigation of ultrafast laser photonic material interactions: challenges for directly written glass photonics

Currently, direct-write waveguide fabrication is probably the most widely studied application of femtosecond laser micromachining in transparent dielectrics. Devices such as buried waveguides, power splitters, couplers, gratings and optical amplifiers have all been demonstrated. Waveguide properties depend critically on the sample material properties and writing laser characteristics. In this paper we discuss the challenges facing researchers using the femtosecond laser direct-write technique with specific emphasis being placed on the suitability of fused silica and phosphate glass as device hosts for different applications.Comment: 11 pages, 87 references, 11 figures. Article in revie

Effect of stellar wind induced magnetic fields on planetary obstacles of non-magnetized hot Jupiters

We investigate the interaction between the magnetized stellar wind plasma and the partially ionized hydrodynamic hydrogen outflow from the escaping upper atmosphere of non- or weakly magnetized hot Jupiters. We use the well-studied hot Jupiter HD 209458b as an example for similar exoplanets, assuming a negligible intrinsic magnetic moment. For this planet, the stellar wind plasma interaction forms an obstacle in the planet's upper atmosphere, in which the position of the magnetopause is determined by the condition of pressure balance between the stellar wind and the expanded atmosphere, heated by the stellar extreme ultraviolet (EUV) radiation. We show that the neutral atmospheric atoms penetrate into the region dominated by the stellar wind, where they are ionized by photo-ionization and charge exchange, and then mixed with the stellar wind flow. Using a 3D magnetohydrodynamic (MHD) model, we show that an induced magnetic field forms in front of the planetary obstacle, which appears to be much stronger compared to those produced by the solar wind interaction with Venus and Mars. Depending on the stellar wind parameters, because of the induced magnetic field, the planetary obstacle can move up to ~0.5-1 planetary radii closer to the planet. Finally, we discuss how estimations of the intrinsic magnetic moment of hot Jupiters can be inferred by coupling hydrodynamic upper planetary atmosphere and MHD stellar wind interaction models together with UV observations. In particular, we find that HD 209458b should likely have an intrinsic magnetic moment of 10-20% that of Jupiter.Comment: 8 pages, 6 figures, 2 tables, accepted to MNRA

Evaluation of biomarkers in the studies of keloid tissue after laser therapy

In this paper, we discuss what biomarkers to choose if there is a need to describe the results of laser therapy targeting keloid skin. We elevate the known cytomarkers (Krt14, Lgals7, Krt5, Dcn, Lum, Igfbp5, Cd31, Vwf, Stambpl1, Uqcrb, Cd3 and Acta2), biomarkers of the inflammatory response (Cd45/Ptprc, Adgre1, Ly6g, Il1b, Il4, Il13, Il22, Cxcl2 и Ccl17), as well as the proteins of extracellular matrix (type I and III collagens; precursors of COL5A1 and COLA1A; FTL, COL3A1, PGLS, CNN2, ANXA2, TPSAB1, COL12A1, precursors of APCS and ALB), and their encoding genes (FGF7, BAX, CCND1, MMP3, MMP9, CXCL1, -2, -5, -6 and -12; IL8, S100A7 and IL1A), those expression and co-location may potentially change the appearance and internal structure of damaged skin. We also describe how to choose biomarkers using the results genomic studies and their limitations. Moreover, we provide examples of how different groups of gene and protein biomarkers are used in experimental biology and clinical practice. According to the previously published data, well-known biomarkers verified on animal models, depend on their biological effects, let to characterize structural changes and changes in the composition of cells represented at the site of damage before and after the treatment. In addition, the published experimental and clinical data provide an opportunity to analyze the efficiency of new experimental approaches and compare them to each other

Sub-critical regime of femtosecond inscription

We apply well known nonlinear diffraction theory governing focusing of a powerful light beam of arbitrary shape in medium with Kerr nonlinearity to the analysis of femtosecond (fs) laser processing of dielectric in sub-critical (input power less than the critical power of selffocusing) regime. Simple analytical expressions are derived for the input beam power and spatial focusing parameter (numerical aperture) that are required for achieving an inscription threshold. Application of non-Gaussian laser beams for better controlled fs inscription at higher powers is also discussed. © 2007 Optical Society of America

Modeling the Lyα\alpha transit absorption of the hot Jupiter HD 189733b

Hydrogen-dominated atmospheres of hot exoplanets expand and escape due to the intense heating by the X-ray and extreme ultraviolet (XUV) irradiation of their host stars. Excess absorption of neutral hydrogen has been observed in the Ly$\alpha$ line during transits of several close-in exoplanets, indicating such extended atmospheres. For the hot Jupiter HD 189733b, this absorption shows temporal variability. Variations in stellar XUV emission and/or stellar wind conditions have been invoked to explain this effect. We apply a 1D hydrodynamic upper atmosphere model and a 3D MHD stellar wind flow model to study the effect of variations of the stellar XUV and wind conditions on the neutral hydrogen distribution, including the production of energetic neutral atoms (ENAs), and the related Ly$\alpha$ transit signature. We obtain comparable, albeit slightly higher Ly$\alpha$ absorption as observed in 2011 with a stellar XUV flux of $1.8\times10^4$ erg cm$^{-2}$ s$^{-1}$, rather typical activity conditions for this star. Flares similar to the one observed 8 h before the transit are unlikely to have caused a significant modulation of the transit signature. The resulting Ly$\alpha$ absorption is dominated by atmospheric broadening, whereas the contribution of ENAs is negligible, as they are formed inside the bow shock from decelerated wind ions that are heated to high temperatures. Thus, within our modeling framework and assumptions, we find an insignificant dependence on the stellar wind parameters. Since the transit absorption can be modeled with typical stellar XUV and wind conditions, it is possible that the non-detection of the absorption in 2010 was affected by less typical stellar activity conditions, such as a very different magnitude and/or shape of the star's spectral XUV emission, or temporal/spatial variations in Ly$\alpha$ affecting the determination of the transit absorption.Comment: 22 pages, 19 figures, 4 tables; A&A, publishe

Peculiarities of Spatial Structure of the Central Caucasian High-Mountain Natural Plague Focus

Within the limits of Central Caucasian high-mountain natural plague focus discovered are two zones of natural focality. The first natural focality zone in the mountain steppe of the eastern part of the focus has a parasitic complex similar in structural organization and functioning to lowland foci of the souslik type. Another one, situated in the western part of the focus, is compatible with Tuva mountain natural plague focus, where fleas Neopsylla setosaare absent, and epizootic activity is characterized by a single-humped curve with an apex for July-August period. The similarities stated above can be used for optimization of epidemiological surveillance techniques, preventive measures, and methodology of studying mountain natural plague foci of the souslik type

On the Stability of a Solution of a Guarantee Optimization Problem under a Functional Constraint on the Disturbance

The paper deals with a control problem for a dynamical system under disturbances. In addition to geometric constraints on the disturbance, it is supposed that all disturbance realizations belong to some unknown L1-compact set. The control is aimed at minimization of a given quality index. Within the game-theoretical approach, the problem of optimizing the guaranteed result is studied. For solving this problem, we use a control procedure with a guide. The paper is focused on the questions of stability of this control procedure with respect to informational and computational errors. The results are illustrated by numerical simulation. © 201

Landscape-Epidemiological Zoning of the Krasnodar Territory and the Republic of Adygea by Tularemia

Objective of the study was epizootic-epidemiological zoning of the area of Krasnodar Territory and the Republic of Adygea by manifestations of tularemia to determine the level of epidemic hazard of each zone.Materials and methods. Utilized were archival data of the Black Sea Plague Control station over the period of 1946–2017 and plague Control Center of the Rospotrebnadzor. With the help of GIS software packages, MapINFO 10.5 and ArcGIS 10.2, the data bases containing the point-like layers of the sites of infection with tularemia (49), isolation of tularemia agent (195), and the layer of landscape-geographical regions in the Krasnodar Territory and the Republic of Adygea were created.Results and discussion. Usage of the geo-information technologies allowed for detailed consideration of tularemia manifestations in different parts of the region. The prospects of applying Arc GIS and MapINFO for geoencoding, processing and creation of geo-information pool of tularemia manifestations over a long period was shown. Vector data of landscapes and sites of epidemics and epizootic manifestations of tularemia on different species of mammals and ticks were generated. The conversion of the database to Microsoft Excel made it possible to make full use of statistical capabilities for epidemiological analysis. The work on epidemiological zoning carried out in the Krasnodar region and the Republic of Adygea starkly illustrated the feasibility of using GIS technologies for those purposes. The results of the analysis allowed for optimization of the mode of epizootiological survey in different parts of the studied region. Advisability of epizootiological inspection and monitoring of the territories with identification of geographical coordinates for epizootic manifestation sites was proved

Ground-based acoustic parametric generator impact on the atmosphere and ionosphere in an active experiment

We develop theoretical basics of active experiments with two beams of acoustic waves, radiated by a ground-based sound generator. These beams are transformed into atmospheric acoustic gravity waves (AGWs), which have parameters that enable them to penetrate to the altitudes of the ionospheric E and F regions where they influence the electron concentration of the ionosphere. Acoustic waves are generated by the ground-based parametric sound generator (PSG) at the two close frequencies. The main idea of the experiment is to design the output parameters of the PSG to build a cascade scheme of nonlinear wave frequency downshift transformations to provide the necessary conditions for their vertical propagation and to enable penetration to ionospheric altitudes. The PSG generates sound waves (SWs) with frequencies f1 = 600 and f2 = 625 Hz and large amplitudes (100-420ms-1). Each of these waves is modulated with the frequency of 0.016 Hz. The novelty of the proposed analytical-numerical model is due to simultaneous accounting for nonlinearity, diffraction, losses, and dispersion and inclusion of the two-stage transformation (1) of the initial acoustic waves to the acoustic wave with the difference frequency Δf = f2 - f1 in the altitude ranges 0-0.1 km, in the strongly nonlinear regime, and (2) of the acoustic wave with the difference frequency to atmospheric acoustic gravity waves with the modulational frequency in the altitude ranges 0.1-20 km, which then reach the altitudes of the ionospheric E and F regions, in a practically linear regime. AGWs, nonlinearly transformed from the sound waves, launched by the two-frequency ground-based sound generator can increase the transparency of the ionosphere for the electromagnetic waves in HF (MHz) and VLF (kHz) ranges. The developed theoretical model can be used for interpreting an active experiment that includes the PSG impact on the atmosphere-ionosphere system, measurements of electromagnetic and acoustic fields, study of the variations in ionospheric transparency for the radio emissions from galactic radio sources, optical measurements, and the impact on atmospheric aerosols. The proposed approach can be useful for better understanding the mechanism of the acoustic channel of seismo-ionospheric coupling

Nonlinear beam tapering and two-dimensional ring solitons

We examine a possibility to exploit the nonlinear lens effect - the initial stage of self-focusing to localize initially broad field distribution into the small central area where wave collapse is arrested - the nonlinear beam tapering. We describe two-dimensional localized solitary waves (ring solitons) in a physical system that presents a linear medium in the central core, surrounded by the cladding with the focusing Kerr nonlinearity. The standard variational analysis demonstrates that such solitons correspond to the minimum of the Hamiltonian