Chirp-control of resonant high-order harmonic generation in indium ablation plumes driven by intense few-cycle laser pulses

We have studied high-order harmonic generation (HHG) in an indium ablation plume driven by intense few-cycle laser pulses centered at 775 nm as a function of the frequency chirp of the laser pulse. We found experimentally that resonant emission lines between 19.7 eV and 22.3 eV (close to the 13th and 15th harmonic of the laser) exhibit a strong, asymmetric chirp dependence, with pronounced intensity modulations. The chirp dependence is reproduced by our numerical time-dependent Schrödinger equation simulations of a resonant HHG by the model indium ion. As demonstrated with our separate simulations of HHG within the strong field approximation, the resonance can be understood in terms of the chirp-dependent HHG photon energy coinciding with the energy of an autoionizing state to ground state transition with high oscillator strength. This supports the validity of the general theory of resonant four-step HHG in the few-cycle limit

Neutron-capture elements in halo, thick-disk, and thin-disk stars. Strontium, yttrium, zirconium, cerium

We derived Sr, Y, Zr, and Ce abundances for a sample of 74 cool dwarfs and subgiants with iron abundances, [Fe/H], between 0.25 and -2.43. These estimates were obtained using synthetic spectra, assuming local thermodynamic equilibrium (LTE) for Y, Zr, and Ce, allowing for non-LTE conditions for Sr. We used high-resolution (λ/Δλ≈40 000 and 60 000) spectra with signal-to-noise ratios between 50 and 200. We find that the Zr/Y, Sr/Y, and Sr/Zr ratios for the halo stars are the same in a wide metallicity range (-2.43 ≤ [Fe/H] ≤ -0.90), within the errors, indicating a common origin for these elements at the epoch of halo formation. The Zr/Y ratios for thick-disk stars quickly decrease with increasing Ba abundance, indicating a lower rate of production of Zr compared to Y during active thick-disk formation. The thick-disk and halo stars display an increase in the [Zr/Ba] ratio with decreasing Ba abundance and a correlation of the Zr and Eu overabundances relative to Ba. The evolutionary behavior of the abundance ratios found for the thick-disk and halo stars does not agree with current models for the Galaxy's chemical evolution. The abundance ratios of Y and Zr to Fe and Ba for thin-disk stars, as well as the abundance ratios within each group, are, on average, solar, though we note a slight decrease of Zr/Ba and Zr/Y with increasing Ba abundance. These results provide evidence for a dominance of asymptotic-giant-branch stars in the enrichment of the interstellar medium in heavy elements during the thin-disk epoch, in agreement with the predictions of the nucleosynthesis theory for the main s-process component. © 2007 Pleiades Publishing, Ltd

Modelling the light variability of the Ap star epsilon Ursae Majoris

We simulate the light variability of the Ap star epsUMa using the observed surface distributions of Fe, Cr, Ca, Mn, Mg, Sr and Ti obtained with the help of Doppler Imaging technique. Using all photometric data available we specified light variations of epsUMa modulated by its rotation from far UV to IR. We employed the LLmodels stellar model atmosphere code to predict the light variability in different photometric systems. The rotational period of epsUMa is refined to 5d088631(18). It is shown that the observed light variability can be explained as a result of the redistribution of radiative flux from the UV spectral region to the visual caused by the inhomogeneous surface distribution of chemical elements. Among seven mapped elements, only Fe and Cr significantly contribute to the amplitude of the observed light variability. In general, we find a very good agreement between theory and observations. We confirm the important role of Fe and Cr to the magnitude of the well-known depression around 5200 \AA\ through the analysis of the peculiar $a$-parameter. Finally, we show that the abundance spots of considered elements cannot explain the observed variability in near UV and $\beta$ index which are likely due to some other causes. The inhomogeneous surface distribution of chemical elements can explain most of the observed light variability of the A-type CP star epsUMa.Comment: Accepted in A&A, 10 pages, 9 figures, 3 table

A NEW CARBON FIBER METHOD FOR MEASUREMENTS OF CONTRACTILE PROPERTIES OF SINGLE CARDIOMYOCYTES

Investigation of the effects of mechanical load on the contractile function of single cardiomyocytes requires the use of new methods to fix the cardiomyocyte. The technique for measuring the mechanical activity of isolated cells using four carbon fibers is used in this study. This method allows one to obtain new experimental data on the effects of mechanical preload applied via diastolic cell stretch on the contractile function of cardiomyocytes.Работа поддержана Постановлением Правительства РФ № 211 от 16.03.2013 и Программой Президиума РАН №27

Modelling of the ultraviolet and visual SED variability in the hot magnetic Ap star CU Vir

The spectral energy distribution (SED) in chemically peculiar stars may be significantly affected by their abundance anomalies. The observed SED variations are usually assumed to be a result of inhomogeneous surface distribution of chemical elements, flux redistribution and stellar rotation. However, the direct evidence for this is still only scarce. We aim to identify the processes that determine the SED and its variability in the UV and visual spectral domains of the helium-weak star CU Vir. We used the model atmospheres to obtain the emergent flux and predict the rotationally modulated flux variability of the star. We show that most of the light variations in the vby filters of the Stromgren photometric system are a result of the uneven surface distribution of silicon, chromium, and iron. Our models are only able to explain a part of the variability in the u filter, however. The observed UV flux distribution is very well reproduced, and the models are able to explain most of the observed features in the UV light curve. The variability observed in the visible is merely a faint gleam of that in the UV. While the amplitude of the light curves reaches only several hundredths of magnitude in the visual domain, it reaches about 1 mag in the UV. The visual and UV light variability of CU Vir is caused by the flux redistribution from the far UV to near UV and visible regions, inhomogeneous distribution of the elements and stellar rotation. Bound-free transitions of silicon and bound-bound transitions of iron and chromium contribute the most to the flux redistribution. This mechanism can explain most of the rotationally modulated light variations in the filters centred on the Paschen continuum and on the UV continuum of the star CU Vir. However, another mechanism(s) has to be invoked to fully explain the observed light variations in the u filter and in the region 2000-2500 A.Comment: 14 pages, 13 figures, accepted for publication in Astronomy and Astrophysic

О проблемах диагностики и лечения пневмоний у детей

Background: Pneumonia is one of the most frequent serious potentially life threatening childhood diseases. The criteria for diagnostics and treatment were designed long ago and are clearly articulated. Nevertheless, diagnostics and therapy happen most often during outpatient management.Objective: The aim was to compare the diagnostic criteria of CAP among children in Russian and foreign guidelines and also to compare the incidence. Another aim is to find out the aptness to the Russian guidelines for the management of CAP among children.Materials and methods: The comparative analysis of childhood pneumonia diagnostics and treatment guidelines have been recently published in a range of countries. We reviewed some recently published pneumonia recommendations. The timeliness and adequacy of hospitalization and treatment was analyzed for 167 hospitalized children with pneumonia diagnosed according to Russian and WHO recommendations. We also used the information about the quality of X-ray pneumonia diagnosis in 679 patients from hospitals in Barnaul, Ekaterinburg and Murmansk (PAPIRUS research project).Results: We found a high percentage of late (5-th day and later) hospitalization of children with pneumonia (37 percent in 2002–2007 and 47 percent in 2013–2014) as well as a late ( 5 days) start of therapy (20 and 34 percent accordingly). In three regional hospitals only 27 percent of X-ray films of children treated for pneumonia were attested as meeting the pneumonia criteria. We found a high frequency of macrolides as a starting therapy in typical pneumonia which often had been ineffective. Amoxicillin/clavulanate and oral cephalosporins were also ineffective in doses < 45 mg/kg/day. A poor knowledge of the clinical features of atypical pneumonia was noted with a corresponding high frequency of -lactams as a starting medication.Conclusion. Our data shows the importance of training paediatricians in modern pneumonia diagnosis and treatment.Актуальность. Пневмония у детей — одно из самых частых, серьезных, потенциально угрожающих жизни заболеваний. Критерии диагностики и лечения пневмонии разработаны давно и четко сформулированы. Тем не менее, приходится сталкиваться с гиподиагностикой и нерациональной терапией, что наблюдается чаще на амбулаторном этапе.Цель: сравнительный анализ показателей заболеваемости, критериев диагностики внебольничных пневмоний у детей в российских и зарубежных рекомендациях и их соответствие действующим в России рекомендациям по диагностике и лечению пневмоний у детей.Материалы и методы. Проведен сравнительный анализ рекомендаций, опубликованных в последнее время в ряде стран, по диагностике и лечению пневмонии у детей. Изучалась своевременность диагностики и адекватность терапии на амбулаторном этапе у 167 госпитализированных детей с пневмонией. Диагноз пневмонии выставлялся согласно российским критериям с учетом рекомендаций ВОЗ. Также использовались данные оценки качества диагностики пневмонии с экспертной оценкой рентгенограмм у 679 больных, госпитализированных в 3 городах (Барнаул, Екатеринбург, Мурманск) в рамках исследования PAPIRUS.Результаты: выявлен высокий процент поздней (после 5-го дня болезни) госпитализации детей с пневмонией (37% — в 2002–2007, 47% — в 2013–2014 гг.), как и позднее (на 5-й день и позднее) начало лечения на амбулаторном этапе (20 и 34%, соответственно). В 3 областных стационарах пневмонические изменения на рентгенограммах были подтверждены экспертом только в 27% случаев.Заключение. Полученные данные указывают на наличие как гипо-, так и гипердиагностики пневмоний у детей, а соответственно, на важность повышения знаний педиатров в области диагностики и лечения пневмоний для оказания адекватной медицинской помощи детям на амбулаторном этапе

Analysis of Mechanical Alternans in Single Cardiomyocytes in Atrial Fibrillation

Atrial fibrillation (AF) has a significant impact on the contractile function of the heart in the form of alternans activity in atrial cardiomyocytes. In this study, we designed a method for evaluating mechanical alternans in atrial cardiomyocytes in AF.Работа выполнена при поддержке государственной темы ИИФ УрО РАН № 122022200089-4

Type 1 Diabetes Impairs Cardiomyocyte Contractility in the Left and Right Ventricular Free Walls but Preserves It in the Interventricular Septum

Type 1 diabetes (T1D) leads to ischemic heart disease and diabetic cardiomyopathy. We tested the hypothesis that T1D differently affects the contractile function of the left and right ventricular free walls (LV, RV) and the interventricular septum (IS) using a rat model of alloxan-induced T1D. Single-myocyte mechanics and cytosolic Ca2+ concentration transients were studied on cardiomyocytes (CM) from LV, RV, and IS in the absence and presence of mechanical load. In addition, we analyzed the phosphorylation level of sarcomeric proteins and the characteristics of the actin-myosin interaction. T1D similarly affected the characteristics of actin-myosin interaction in all studied regions, decreasing the sliding velocity of native thin filaments over myosin in an in vitro motility assay and its Ca2+ sensitivity. A decrease in the thin-filament velocity was associated with increased expression of β-myosin heavy-chain isoform. However, changes in the mechanical function of single ventricular CM induced by T1D were different. T1D depressed the contractility of CM from LV and RV; it decreased the auxotonic tension amplitude and the slope of the active tension-length relationship. Nevertheless, the contractile function of CM from IS was principally preserved. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.Funding: This work was supported by the Russian Science Foundation № 18-74-10059. The work was performed using the equipment of the Shared Research Center of Scientific Equipment of Institute of Immunology and Physiology

DEVELOPMENT OF METHOD FOR ANALYSIS OF THE T-TUBULAR SYSTEM IN RAT CARDIOMYOCYTES

The t-system is the highly structured network of membrane invaginations playing an im-portant role in the regulation of cardiac electromechanical coupling and contraction. We de-signed an approach to evaluate the structure of the cardiomyocyte t-tubular system in detail.При поддержке гос.задания ИИФ УрО РАН (тема № AAAA-A19-119070190064-4)

Catalog of Galactic Beta Cephei Stars

We present an extensive and up-to-date catalog of Galactic Beta Cephei stars. This catalog is intended to give a comprehensive overview of observational characteristics of all known Beta Cephei stars. 93 stars could be confirmed to be Beta Cephei stars. For some stars we re-analyzed published data or conducted our own analyses. 61 stars were rejected from the final Beta Cephei list, and 77 stars are suspected to be Beta Cephei stars. A list of critically selected pulsation frequencies for confirmed Beta Cephei stars is also presented. We analyze the Beta Cephei stars as a group, such as the distributions of their spectral types, projected rotational velocities, radial velocities, pulsation periods, and Galactic coordinates. We confirm that the majority of these stars are multiperiodic pulsators. We show that, besides two exceptions, the Beta Cephei stars with high pulsation amplitudes are slow rotators. We construct a theoretical HR diagram that suggests that almost all 93 Beta Cephei stars are MS objects. We discuss the observational boundaries of Beta Cephei pulsation and their physical parameters. We corroborate that the excited pulsation modes are near to the radial fundamental mode in frequency and we show that the mass distribution of the stars peaks at 12 solar masses. We point out that the theoretical instability strip of the Beta Cephei stars is filled neither at the cool nor at the hot end and attempt to explain this observation