Digital receivers for low-frequency radio telescopes UTR-2, URAN, GURT

This paper describes digital radio astronomical receivers used for decameter and meter wavelength observations. This paper describes digital radio astronomical receivers used for decameter and meter wavelength observations. Since 1998, digital receivers performing on-the-fly dynamic spectrum calculations or waveform data recording without data loss have been used at the UTR-2 radio telescope, the URAN VLBI system, and the GURT new generation radio telescope. Here we detail these receivers developed for operation in the strong interference environment that prevails in the decameter wavelength range. Data collected with these receivers allowed us to discover numerous radio astronomical objects and phenomena at low frequencies, a summary of which is also presented.Comment: 24 pages, 15 figure

Results of lumbar interbody fusion in elderly patients with lumbar spinal stenosis associated with cauda equina syndrome

Background: Currently, there are no clear recommendations on the timing of surgical intervention for the slow development of cauda equina syndrome (CES) against the background of lumbar spinal stenosis (LSS) at the lumbar level in elderly patients. The information on the long-term effectiveness of decompressive and stabilizing interventions (DSI) in the lumbar spine in this pathology is also limited.Objective: To conduct a comparative analysis of the results of surgical treatment of elderly patients with LSS associated with CES after open and low-traumatic DSI.Material and methods: The retrospective study included 37 patients operated on between 2000 and 2020 for CES caused by LSS. Two groups were distinguished: in the first group (n = 17), an open DSI was performed with the median approach, in the second group (n = 20) a low-traumatic DSI was performed according to the author’s method. Technical features of interventions and specificity of the postoperative period, preoperative instrumental data, clinical parameters in dynamics, and complications were compared.Results: In a comparative analysis in the group of patients operated on with author’s low-traumatic DSI, smaller parameters were registered: the duration of the operation (p = 0.02), the blood loss (p = 0.003), the duration of inpatient treatment (p = 0.002), and the postoperative need for opioid analgesics (p < 0.05). In catamnesis, statistically significantly better clinical parameters of bladder sphincter control (p = 0.02) and motor function recovery (p = 0.01), Oswestry Disability Index (ODI) (p = 0.03) and the Short Form-36 (SF-36) (p = 0.01) were observed in patients of the group II, compared with the group I. A greater number of complications were noticed in the group of open DSI (p = 0.003), with a comparable frequency of reoperations in the follow-up period (p = 0.79).Conclusion: In elderly patients with CES-associated LSS, the advantages of the author’s low-traumatic DSI in comparison with open DSI were established of less blood loss and duration of hospitalization, low need for postoperative analgesia, the minimum number of complications, and the dynamics of neurological symptoms, better recovery of ODI and SF-36 in catamnesis

Spallative ablation of dielectrics by X-ray laser

Short laser pulse in wide range of wavelengths, from infrared to X-ray, disturbs electron-ion equilibrium and rises pressure in a heated layer. The case where pulse duration $\tau_L$ is shorter than acoustic relaxation time $t_s$ is considered in the paper. It is shown that this short pulse may cause thermomechanical phenomena such as spallative ablation regardless to wavelength. While the physics of electron-ion relaxation on wavelength and various electron spectra of substances: there are spectra with an energy gap in semiconductors and dielectrics opposed to gapless continuous spectra in metals. The paper describes entire sequence of thermomechanical processes from expansion, nucleation, foaming, and nanostructuring to spallation with particular attention to spallation by X-ray pulse

Stem rust in Western Siberia – race composition and effective resistance genes

Stem rust in recent years has acquired an epiphytotic character, causing significant economic damage  for wheat production in some parts of Western Siberia. On the basis of a race composition study of the stem rust  populations collected in 2016–2017 in Omsk region and Altai Krai, 13 pathotypes in Omsk population and 10 in  Altai population were identified. The race differentiation of stem rust using a tester set of 20 North American  Sr genes differentiator lines was carried out. The genes of stem rust pathotypes of the Omsk population are avirulent only to the resistance gene Sr31, Altai isolates are avirulent not only to Sr31, but also to Sr24, and Sr30. A low  frequency of virulence (10–25 %) of the Omsk population pathotypes was found for Sr11, Sr24,Sr30, and for Altai  population – Sr7b,Sr9b,Sr11,SrTmp, which are ineffective in Omsk region. Field evaluations of resistance to stem  rust were made in 2016–2018 in Omsk region in the varieties and spring wheat lines from three different sources.  The first set included 58 lines and spring bread wheat varieties with identified Sr genes – the so-called trap nursery  (ISRTN – International Stem Rust Trap Nursery). The second set included spring wheat lines from the Arsenal collection, that were previously selected according to a complex of economically valuable traits, with genes for resistance  to stem rust, including genes introgressed into the common wheat genome from wild cereal species. The third  set included spring bread wheat varieties created in the Omsk State Agrarian University within the framework of  a shuttle breeding program, with a synthetic wheat with the Ae. tauschiigenome in their pedigrees. It was established that the resistance genes Sr31, Sr40,Sr2 complexare effective against stem rust in the conditions of Western  Siberia. The following sources with effective Srgenes were selected: (Benno)/6*LMPG-6 DK42, Seri 82, Cham 10,  Bacanora (Sr31), RL 6087 Dyck (Sr40), Amigo (Sr24,1RS-Am), Siouxland (Sr24,Sr31), Roughrider (Sr6, Sr36), Sisson  (Sr6,Sr31,Sr36), and Fleming (Sr6,Sr24,Sr36,1RS-Am), Pavon 76 (Sr2 complex) from the ISRTN nursery; No. 1 BC 1F2 (96 × 113) × 145 × 113 (Sr2,Sr36,Sr44), No. 14а F 3(96 × 113) × 145 (Sr36,Sr44), No. 19 BC 2F3(96 × 113) × 113 (Sr2, Sr36, Sr44), and No. 20 F 3 (96 × 113) × 145  (Sr2,Sr36,Sr40, Sr44) from the Arsenal collection; and the Omsk State Agrarian  University varieties Element 22 (Sr31,Sr35), Lutescens 27-12, Lutescens 87-12 (Sr23,Sr36), Lutescens 70-13, and  Lutescens 87-13 (Sr23,Sr31,Sr36). These sources are recommended for inclusion in the breeding process for developing stem rust resistant varieties in the region

Влияние молекулярной массы на процесс электроформования волокнистых материалов, полученных из растворов полиакрилонитрила

In the article influence of the molecular weight of polyacrylonitrile on electrospinning process and also on the diameter and mechanical properties of the obtained fibers and fiber materials are considered. Polymers with molecular weight from 280 000 to 700 000 were investigated. Fibers with a diameter from 200 to 1100 nm were obtained.В статье рассматривается влияние молекулярной массы полиакрилонитрила на диаметр и механические свойства полученных волокон и волокнистых материалов. Исследованы полимеры с молекулярной массой от 280 000 до 700 000. Получены волокна с диаметром от 200-1100 нм

КЛИНИЧЕСКАЯ И МИКРОХИРУРГИЧЕСКАЯ АНАТОМИЯ ИЛЕОЦЕКАЛЬНОГО КЛАПАНА

The article reflects the need for extensive use in the application of fundamental anatomical studies ileocecal region results research methods, quantitative estimates of the morphological parameters, that are opening new possibilities for diagnosis of pathological processes and development of new ways of operating.В статье отражена необходимость широкого использования в фундаментальных анатомических исследованиях илеоцекальной области результатов прижизненных методов исследования, количественной оценки морфологических параметров, которые открывают новые возможности для диагностики патологических процессов и разработки новых приемов оперирования.

Исследование процесса растяжения жидкой полимерной струи в электрическом поле из растворов полиакрилонитрила

The article considers stretching of liquid polyacrylonitrile jet in electrostatic field. Polymers with molecular weight from 130 000 to 700 000 were investigated. Regularities of stretching of the jet based on polyacrylonitrile solutions were determined.В статье рассматривается процесс растяжения жидкой полимерной струи растворов полиакрилонитрила (ПАН) находящейся в электрическом поле. Исследованы полимеры с молекулярной массой от 130 000 до 700 000. Установлены основные закономерности процесса растяжения струи на основе растворов ПАН