4,270 research outputs found
DEVELOPMENT OF SIMPLIFIED METHOD OF ESTIMATION OF DEFORMATION PROCESSING OF CENTRAL ZONES OF ROLLOUT SECTION FROM CONTINUOUS COLLECTION IN ROLLING IN CALIBERS
Development of a simplified method of estimation of deformation
processing of central zones of rollout section from continuous collection in rolling in
calibers
Detection of Giant Radio Pulses from the Pulsar PSR B0656+14
Giant pulses (GPs) have been detected from the pulsar PSR B0656+14. A pulse
that is more intense than the average pulse by a factor of 120 is encountered
approximately once in 3000 observed periods of the pulsar. The peak flux
density of the strongest pulse, 120 Jy, is a factor of 630 higher than that of
the average pulse. The GP energy exceeds the energy of the average pulse by up
to a factor of 110, which is comparable to that for other known pulsars with
GPs, including the Crab pulsar and the millisecond pulsar PSR B1937+21. The
giant pulses are a factor of 6 narrower than the average pulse and are
clustered at the head of the average pulse. PSR B0656+14 along with PSR
B0031-07, PSR B1112+50, and PSR J1752+2359 belong to a group of pulsars that
differ from previously known ones in which GPs have been detected without any
extremely strong magnetic field on the light cylinder.Comment: 10 pages, 3 figures, 1 table; originally published in Russian in
Pis'ma Astron. Zh., 2006, v.32, 650; translated by George Rudnitskii; the
English version will be appear in Astronomy Letter
Instantaneous Radio Spectra of Giant Pulses from the Crab Pulsar from Decimeter to Decameter Wavelengths
The results of simultaneous multifrequency observations of giant radio pulses
from the Crab pulsar, PSR B0531+21, at 23, 111, and 600 MHz are presented and
analyzed. Giant pulses were detected at a frequency as low as 23 MHz for the
first time. Of the 45 giant pulses detected at 23 MHz, 12 were identified with
counterparts observed simultaneously at 600 MHz. Of the 128 giant pulses
detected at 111 MHz, 21 were identified with counterparts observed
simultaneously at 600 MHz. The spectral indices for the power-law frequency
dependence of the giant-pulse energies are from -3.1 to -1.6. The mean spectral
index is -2.7 +/- 0.1 and is the same for both frequency combinations (600-111
MHz and 600-23 MHz). The large scatter in the spectral indices of the
individual pulses and the large number of unidentified giant pulses suggest
that the spectra of the individual giant pulses do not actually follow a simple
power law. The observed shapes of the giant pulses at all three frequencies are
determined by scattering on interstellar plasma irregularities. The scatter
broadening of the pulses and its frequency dependence were determined as
tau_sc=20*(f/100)^(-3.5 +/- 0.1) ms, where the frequency f is in MHz.Comment: 13 pages, 1 figure, 1 table (originally published in Russian in
Astronomicheskii Zhurnal, 2006, vol. 83, No. 7, pp. 630-637), translated by
Georgii Rudnitski
Detection of Giant Pulses from the Pulsar PSR B0031-07
Giant pulses have been detected from the pulsar PSR B0031-07. A pulse with an
intensity higher than the intensity of the average pulse by a factor of 50 or
more is encountered approximately once per 300 observed periods. The peak flux
density of the strongest pulse is 530 Jy, which is a factor of 120 higher than
the peak flux density of the average pulse. The giant pulses are a factor of 20
narrower than the integrated profile and are clustered about its center.Comment: 7 pages, 2 figures, to appear in: Pis'ma v Astronomicheskii Zhurnal,
2004, v.30, No.4, and will be translated as: Astronomy Letters, v.30, No.
Ischemic stroke as a complex mathematical system
As a result of the mathematical analysis significant differences in risks of the development of lethal outcomes in different locations and pathogenetic subtypes of ischemic stroke were revealed. Based on this, the principles of moving the patient inside the hospital were proposed. The results of mathematical modeling allowed us to determine the group of patients with high risks of pneumonia, pulmonary embolism and group of cardiac complications development. Some approaches for preventing complications depending on the severity of stroke were offered.В результате проведенного математического анализа были выявлены достоверные различия рисков развития летальных исходов при различных локализациях и патогенетических подтипах ишемического инсульта, на основании чего были предложены принципы перемещения больного в стационаре. Результаты математического моделирования позволили определить группы больных с высокими рисками развития пневмонии, тромбоэмболии легочной артерии и группы кардиальных осложнений. Предложены подходы по профилактике осложнений в зависимости от тяжести инсульта
The Small-angle X-Ray Scattering Investigation of Advanced Beryllium Materials
The small-angle X-ray scattering (SAXS) technique allows to determine size distributions of inhomogeneities in materials and to predict their properties in Xray optics devices. A number of beryllium materials for the manufacturing of X-ray optics (refractive lenses and speckle suppressors) have been studied by the SAXS.Various composite materials based on porous beryllium have been studied. The effect of adding detonation nanodiamonds to the beryllium matrix on the scattering ability of the material is discussed.
Keywords: porous beryllium, SAXS, detonation nanodiamonds, speckle-suppresso
Determination of Priority Customers for Small and Medium-Sized Machine-Building Enterprises
The article is devoted to the selection of priority customers from among new customers for small and medium-sized machine-building enterprises. The analysis of the dynamics of sales from new and existing customers for ten enterprises allowed us to offer the coefficient of its potential as a criterion for evaluating the customer. The potential coefficient shows the increase in the cost of subsequent orders compared to the first order. The correlation and regression analysis revealed the main factors that determine the customer's potential coefficient. They are the number of years of presence in the market and the profitability of sales of the customer. The introduction of the potential coefficient in the target function of the optimization task of forming a portfolio of orders will allow you to select and retain priority customers. © 2022 American Institute of Physics Inc.. All rights reserved
Analysis of the placental tissue transcriptome of normal and preeclampsia complicated pregnancies
Preeclampsia is one of the most severe gestational complications which is one of the leading causes of maternal and perinatal morbidity and mortality. A growth in the incidence of severe and combined forms of the pathology has been observed in recent years. According to modern concepts, inadequate cytotrophoblast invasion into the spiral arteries of the uterus and development of the ischemia-reperfusion syndrome in the placental tissue play the leading role in the development of preeclampsia, which is characterized by multipleorgan failure. In this regard, our work was aimed at studying the patterns of placental tissue transcriptome that are specific to females with PE and with physiological pregnancy, as well as identifying the potential promising biomarkers and molecular mechanisms of this pathology. We have identified 63 genes whose expression proved to differ significantly in the placental tissue of females with PE and with physiological pregnancy. A cluster of differentially expressed genes (DEG) whose expression level is increased in patients with preeclampsia includes not only the known candidate genes that have been identified in many other genome-wide studies (e.g., LEP, BHLHB2, SIGLEC6, RDH13, BCL6), but also new genes (ANKRD37, SYDE1, CYBA, ITGB2, etc.), which can be considered as new biological markers of preeclampsia and are of further interest. The results of a functional annotation of DEG show that the development of preeclampsia may be related to a stress response, immune processes, the regulation of cell-cell interactions, intracellular signaling cascades, etc. In addition, the features of the differential gene expression depending on preeclampsia severity were revealed. We have found evidence of the important role of the molecular mechanisms responsible for the failure of immunological tolerance and initiation of the pro-inflammatory cascade in the development of severe preeclampsia. The results obtained elaborate the concept of the pathophysiology of preeclampsia and contain the information necessary to work out measures for targeted therapy of this disease.
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