109 research outputs found

    The accumulation of femtosecond laser radiation energy in crystals of lithium fluoride

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    We present the results of studies of energy accumulation during the non-destructive interaction of extremely intense near infrared laser radiation with model wide band gap dielectric crystals of lithium fluoride, when the intensity of pulses is sufficient for effective highly nonlinear absorption of light and for the excitation of the electron subsystem of matter and the energy of pulses is still not sufficient for significant heating, evaporation, laser breakdown or other destruction to occur. We studied the emission of energy in the form of light sum of thermally stimulated luminescence accumulated under conditions of self-focusing and multiple filamentation of femtosecond laser radiation. It was established that it's the F2 and F[3]{+} color centers and supplementary to them centers of interstitial type which accumulate energy under the action of a single femtosecond laser pulses. When irradiated by series of pulses the F3, F[3]{-} and F[4] centers additionally appear. F2 centers are the main centers of emission in the process of thermally stimulated luminescence of accumulated energy. The interstitial fluoride ions (I-centers) are the kinetic particles. They split off from the X[3]{-} centers in the result of thermal decomposition of latter on the I-centers and molecules X[2]{0}. I-centers recombine with F[3]{+} centers and form F[2] centers in excited state. The latter produce the characteristic emission spectrum emitted in the form of thermally stimulated luminescence

    Особенности течения инфекционного артрита у пациента с гипогаммаглобулинемией

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    Hypogammaglobulinemia is a condition caused by low levels of immunoglobulins in the blood serum. It can be a manifestation of primary immunodeficiency, characterized by a violation of the production of immunoglobulins, in particular common variable immunodeficiency (CVID). A typical clinical sign of CVID is various severe infections, among which infectious arthritis is not uncommon. At the same time, the clinical picture of infections can differ significantly from that in individuals with a normal immune response, including the spectrum of infectious arthritis pathogens.The article describes a clinical case of an unusual course of infectious arthritis in a patient with newly diagnosed hypogammaglobulinemia. The peculiar features of the case were a long (more than 1.5 years) course of the disease, without the development of septic complications, no increase in ESR and CRP, recurrence of arthritis after a 2-month course of antibiotic therapy, and the presence of generalized edema. The causes and diagnosis, features of infectious complications, including infectious arthritis, and probable causes of edematous syndrome in CVID are discussed.Гипогаммаглобулинемия – состояние, обусловленное низким уровнем иммуноглобулинов в сыворотке крови. Она может быть проявлением первичного иммунодефицита, характеризующегося нарушением продукции иммуноглобулинов, в частности общей вариабельной иммунной недостаточностью (ОВИН). Типичным клиническим признаком ОВИН являются различные инфекции тяжелого течения, среди которых нередки и инфекционные артриты. При этом клиническая картина инфекций может значительно отличаться от таковой у лиц с нормальным иммунным ответом, в том числе спектром возбудителей инфекционного артрита. В статье описано клиническое наблюдение необычного течения инфекционного артрита у пациента с впервые выявленной гипогаммаглобулинемией. Особенностями случая были длительное (более 1,5 лет) течение заболевания без развития септических осложнений, отсутствие повышения СОЭ и СРБ, рецидив артрита после 2-месячного курса антибактериальной терапии, а также наличие генерализованных отеков. Обсуждаются причины и диагностика, особенности инфекционных осложнений, в том числе инфекционных артритов, и вероятные причины отечного синдрома при ОВИН

    Новые виды и наиболее интересные находки для флоры Урала и прилегающих территорий

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    The article provides information about rare and newly described species for the flora of the Urals and adjacent territories, namely: Astragalus saphronovae Kulikov, Atraphaxis decipiens Jaub. et Spach., Carex amgunensis F. Schmidt, Galium densiflorum Ledeb., Jovibarba globifera (L.) J. Parn., Najas minor All., Potamogeton nodosus Poir., Pseudorchis albida (L.) Á. Löve et D. Löve, Salix myrsinites L., Veronica agrestis L. Essays include the information on the species ecology and short taxonomic notes. © 2021 Altai State University. All rights reserved.The work was supported by the state assignments: АААА-А19-119031290052-1 “Sosudistye rasteniia Evrazii: sistematika, flora, rastitelʹnye resursy” [“Vascular plants of Eurasia: systematics, flora, plant resources”], АААА-А18-118011990151-7 “Izucheniye, sokhraneniye i rasshireniye bioraznoobraziya rasteniy v prirode i pri introduktsii na Yuzh nom Urale i Priuralye” [“Study, conservation and expansion of plant biodiversity in nature and during introduction in the Southern Urals and the Cis- and Trans-Urals region”], AAAA-A17-117050400146-5 “Otsenka prostranstvennovremennoy izmenchivosti bioraznoobraziya i usloviy yego formirovaniya na Severe Zapadnoy Sibiri v svyazi s izmeneniyem klimata i osvoyeniyem neftegazovykh resursov” [“Assessment of the spatio-temporal variability of biodiversity and the conditions for its formation in the north of Western Siberia in connection with climate change and the development of oil and gas resources”], and by “Programmoy povysheniya konkurentosposobnosti Uralskogo federalnogo universiteta” [“The program for improving the competitiveness of the Ural Federal University”] (the decree no. 211 of the Government of the Russian Federation, contract no. 02.A03.21.0006)

    Pteridophyte Distribution of the Urals and Adjacent Areas: a Dataset

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    Background Data on the species diversity and distribution of pteridophytes (lycophytes and ferns) in the Urals and adjacent areas are presented. The dataset includes 13,742 observations of two classes Lycopodiopsida and Polypodiopsida. In total, the dataset contains information on 16 families, 28 generas, 65 species, four subspecies and nine interspecies hybrids. All records are for lycophytes and ferns collected over 170 years between 1853 and 2021. The dataset presented is based on herbarium specimens, published data and field research conducted by the authors. This dataset is the first and important step towards generalising information on the current diversity and geographical distribution of pteridophytes in the Urals and adjacent areas. © Melnikov D et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Funding: This work was supported in part by the Program for Improving the Competitiveness of the Ural Federal University (the decree no. 211 of the Government of the Russian Federation, contract No. 02.A03.21.0006), the state assignments АААА-А19-119031290052-1 (Komarov Botanical Institute RAS), no. 0111-2019-0001 (Tsitsin Main Botanical Garden of the RAS), no. AAAA-A17-117072810011-1 (Institute Botanical Garden UB RAS) and no. АААА-А19-119031890084-6 (Institute of Plant and Animal Ecology UB RAS). This research was carried out within the project No. 121041600045-8 "Western Siberia in the context of Eurasian ties: man, nature, society". We thank the Ministry of Higher Education and Science of Russian Federation for the supportgiven to the Center of Collective Use “Herbarium MBG RAS” (Agreement No. 075-15-2021-678). The work was carried out as part of the Russia 2021 project

    Influence of the ocean surface temperature and sea ice concentration on regional climate changes in Eurasia in recent decades

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    Numerical experiments with the ECHAM5 atmospheric general circulation model have been performed in order to simulate the influence of changes in the ocean surface temperature (OST) and sea ice concentration (SIC) on climate characteristics in regions of Eurasia. The sensitivity of winter and summer climates to OST and SIC variations in 1998-2006 has been investigated and compared to those in 1968-1976. These two intervals correspond to the maximum and minimum of the Atlantic Long-Period Oscillation (ALO) index. Apart from the experiments on changes in the OST and SIC global fields, the experiments on OST anomalies only in the North Atlantic and SIC anomalies in the Arctic for the specified periods have been analyzed. It is established that temperature variations in Western Europe are explained by OST and SIC variations fairly well, whereas the warmings in Eastern Europe and Western Siberia, according to model experiments, are substantially (by a factor of 2-3) smaller than according to observational data. Winter changes in the temperature regime in continental regions are controlled mainly by atmospheric circulation anomalies. The model, on the whole, reproduces the empirical structure of changes in the winter field of surface pressure, in particular, the pressure decrease in the Caspian region; however, it substantially (approximately by three times) underestimates the range of changes. Summer temperature variations in the model are characterized by a higher statistical significance than winter ones. The analysis of the sensitivity of the climate in Western Europe to SIC variations alone in the Arctic is an important result of the experiments performed. It is established that the SIC decrease and a strong warming over the Barents Sea in the winter period leads to a cooling over vast regions of the northern part of Eurasia and increases the probability of anomalously cold January months by two times and more (for regions in Western Siberia). This effect is caused by the formation of the increased-pressure region with a center over the southern boundary of the Barents Sea during the SIC decrease and an anomalous advection of cold air masses from the northeast. This result indicates that, to estimate the ALO actions (as well as other long-scale climatic variability modes) on the climate of Eurasia, it is basically important to take into account (or correctly reproduce) Arctic sea ice changes in experiments with climatic models

    ICRF plasmas for fusion reactor applications

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    The ICRF plasma production technique is considered as a promising alternative tool for the following applications in the present and next generation superconducting fusion devices: (i) Wall conditioning in the presence of permanent high magnetic field; (ii) Assistance for the tokamak start-up at low inductive electric field (E₀ ~ 0.3 V/m in ITER); (iii) Target dense plasma production (ne ≥ 10¹⁹ m⁻³) in stellarators. The paper presents a review of the ICRF plasma production technique and its applications in the present-day tokamaks and stellarators. The perspective of the alternative technique applications in ITER is analyzed in the frame of 0-D plasma modeling.ВЧ-метод утворення плазми (ICRF) розглядається як перспективний альтернативний інструмент для таких застосувань у сучасних й майбутніх надпровідних термоядерних установках: (i) ВЧ-чистка стінок в присутності постійного сильного магнітного поля; (ii) Aсистування старту токамака у режимі слабого вихрового електричного поля (E₀~ 0.3 В/м в ITERі); (iii) Створення густої вихідної плазми (ne ≥ 10¹⁹ м⁻³) в стелараторах. Зроблено огляд ВЧ-метода створення плазми та його застосування у сучасних токамаках й стелараторах. В рамках моделювання 0-D плазмовим кодом проведено аналіз перспективності використання даного метода в ITERі.ВЧ-метод создания плазмы (ICRF) рассматривается как перспективный альтернативный инструмент для следующих применений в современных и будущих сверхпроводящих термоядерных установках: (i) ВЧ-чистка стенок в присутствии постоянного сильного магнитного поля; (ii) Aссистирование старту токамака в режиме слабого вихревого электрического поля (E₀ ~ 0.3 В/м в ITERе); (iii) Создание плотной исходной плазмы (ne ≥ 10¹⁹ м⁻³) в стеллараторах. Сделан обзор ВЧ-метода создания плазмы и его применений в современных токамаках и стеллараторах. В рамках моделирования 0-D плазменным кодом проведен анализ перспективности использования данного метода в ITERе

    Blood pressure-lowering effects of nifedipine/candesartan combinations in high-risk individuals: Subgroup analysis of the DISTINCT randomised trial

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    The DISTINCT study (reDefining Intervention with Studies Testing Innovative Nifedipine GITS - Candesartan Therapy) investigated the efficacy and safety of nifedipine GITS/candesartan cilexetil combinations vs respective monotherapies and placebo in patients with hypertension. This descriptive sub-analysis examined blood pressure (BP)-lowering effects in high-risk participants, including those with renal impairment (estimated glomerular filtration rate<90 ml min-1, n=422), type 2 diabetes mellitus (n=202), hypercholesterolaemia (n=206) and cardiovascular (CV) risk factors (n=971), as well as the impact of gender, age and body mass index (BMI). Participants with grade I/II hypertension were randomised to treatment with nifedipine GITS (N) 20, 30, 60 mg and/or candesartan cilexetil (C) 4, 8, 16, 32 mg or placebo for 8 weeks. Mean systolic BP and diastolic BP reductions after treatment in high-risk participants were greater, overall, with N/C combinations vs respective monotherapies or placebo, with indicators of a dose-response effect. Highest rates of BP control (ESH/ESC 2013 guideline criteria) were also achieved with highest doses of N/C combinations in each high-risk subgroup. The benefits of combination therapy vs monotherapy were additionally observed in patient subgroups categorised by gender, age or BMI. All high-risk participants reported fewer vasodilatory adverse events in the pooled N/C combination therapy than the N monotherapy group. In conclusion, consistent with the DISTINCT main study outcomes, high-risk participants showed greater reductions in BP and higher control rates with N/C combinations compared with respective monotherapies and lesser vasodilatory side-effects compared with N monotherapy

    Large-Eddy Simulations of Magnetohydrodynamic Turbulence in Heliophysics and Astrophysics

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    We live in an age in which high-performance computing is transforming the way we do science. Previously intractable problems are now becoming accessible by means of increasingly realistic numerical simulations. One of the most enduring and most challenging of these problems is turbulence. Yet, despite these advances, the extreme parameter regimes encountered in space physics and astrophysics (as in atmospheric and oceanic physics) still preclude direct numerical simulation. Numerical models must take a Large Eddy Simulation (LES) approach, explicitly computing only a fraction of the active dynamical scales. The success of such an approach hinges on how well the model can represent the subgrid-scales (SGS) that are not explicitly resolved. In addition to the parameter regime, heliophysical and astrophysical applications must also face an equally daunting challenge: magnetism. The presence of magnetic fields in a turbulent, electrically conducting fluid flow can dramatically alter the coupling between large and small scales, with potentially profound implications for LES/SGS modeling. In this review article, we summarize the state of the art in LES modeling of turbulent magnetohydrodynamic (MHD) ows. After discussing the nature of MHD turbulence and the small-scale processes that give rise to energy dissipation, plasma heating, and magnetic reconnection, we consider how these processes may best be captured within an LES/SGS framework. We then consider several special applications in heliophysics and astrophysics, assessing triumphs, challenges,and future directions
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