Abstract
This article presents the early results of synchronous multiwavelength observations of one of the brightest gamma-ray bursts (GRBs) GRB 160625B with the detailed continuous fast optical ...photometry of its optical counterpart obtained by MASTER and with hard X-ray and gamma-ray emission, obtained by the Lomonosov and Konus-Wind spacecraft. The detailed photometry led us to detect the quasi-periodical emission components in the intrinsic optical emission. As a result of our analysis of synchronous multiwavelength observations, we propose a three-stage collapse scenario for this long and bright GRB. We suggest that quasiperiodic fluctuations may be associated with forced precession of a self-gravitating rapidly rotating superdense body (spinar), whose evolution is determined by a powerful magnetic field. The spinar’s mass allows it to collapse into a black hole at the end of evolution.
This paper considers latest highlights in simultaneous and follow-up optical observations of high energy astrophysical phenomena by MASTER Global Robotic Net. Such extreme Universe sources includes ...gamma-ray bursts, gravitational wave events, detected by LIGO/Virgo, fast radio bursts, high energy neutrino sources and others. Some of the neutrinos detected by ground-based facilities owe their births to supermassive black holes – blazars, which are in a special anxious state with high statistical reliability. We discovered the effect of a rapid decrease in the brightness of the blazar PKS 0735+17 at the time of the multiple detection of the high-energy neutrino event IceCube-211208A. This decrease in brightness within several hours was detected with a high confidence (SNR 10) in comparison with a multi-day brightening state of the blazar, which was accompanied not only by a maximum increase in the average brightness, but also by an increase in the amplitude of its brightness fluctuations. Additionally, we analyzed all cases of successful observation of blazars around neutrino events and obtained statistically reliable indications of the relationship between neutrino events and optical activity of blazars in the doubled error box at the 4.2
level.
Dispersion of the dielectric constant of ferroelectric ceramics based on (K,Na)NbO
3
modified by barium titanate with a concentration of 0.01, 0.02 and 0.04 mol % is studied in the temperature range ...of 25–120°C. Patterns in the effect the modifying additive has on the dispersion of the dielectric constant in the frequency range of 0.25–10
5
Hz are determined.
The prevalence and structure of chronic non-viral liver disease of military personnel whose service is associated with the influence of various military-professional factors are estimated. It is ...established that the frequency of chronic diffuse liver diseases of viral etiology in a group of servicemen radio-technical troops was 77,3%, from persons engaged in diving and altitude descents 65,9%, pilots of the aerospace defence forces of Russia 62,8%, in persons without exposure to military occupational factors is 69,5%. The largest number of persons suffering from chronic non-viral liver disease in the group of military radio-technical troops, probably related to low levels of physical activity and higher values of body mass index and waist circumference, but also the influence of microwave radiation, can enhance the damaging effects of lipid peroxidation. The lowest prevalence of non-viral chronic diffuse liver diseases among pilots and aquanauts is probably related to the maximum health requirements imposed on military personnel of these categories. It was found that the level of alcohol consumption and the nature of nutrition in the study groups did not significantly differ. The highest values of body mass index and waist circumference in combination with the lowest level of physical activity were observed in the group of military personnel of the radio engineering troops, which is probably due to the nature of daily military service, which is mainly sedentary. Among the metabolic changes of blood serum, increased total cholesterol levels in groups of divers, pilots and military Radio-technical troops compared with a control. In addition, the level of glucose in Aquanauts, as well as triglycerides in soldiers of the radio engineering troops was higher than in the control group. Ultrasound examination in all groups related to the impact of military occupational factors, recorded an increase in the thickness of the left lobe of the liver, and oblique vertical size and thickness of the right lobe in the group of soldiers of the radio-technical troops compared with a control. In addition, the values of the thickness of the intima-media complex as a marker of preclinical atherosclerosis associated with non-alcoholic and alcoholic-metabolic fatty liver diseases in this category of individuals significantly exceed them in the other groups. The maximum level of liver damage in the group of military personnel of radio engineering troops is confirmed by the highest values of the controlled parameter of attenuation of ultrasound, reflecting the degree of liver steatosis.
A study of low-frequency relaxation of polarization in conventionally prepared ceramic compounds of (1-x)(K
0.5
Na
0.5
)(Nb
0.93
Sb
0.07
)O
3
+xBaTiO
3
+0.5mol.%MnO
2
(x = 0.02, 0.04) examined over a ...wide temperature range is reported. Anomalous behavior of the temperature dependence of the coercive field E
c
(T) is detected in the temperature range of the orthorhombic to tetragonal phase transition. The observed features of polarization are assigned to dynamics of the domain structure at the temperature range of phase coexistence.
Processes of the polarization and repolarization of ferroelectric ceramics based on potassium sodium niobate in the region of infralow frequencies are discussed. The effect aging and subsequent ...annealing in a strong alternating electric field have on the nonlinearity of the dielectric response of a sample at different temperatures is determined.
Results of polarization and polarization switching in samples prepared by solid phase synthesis of the (1-x)(K.sub.0.5Na.sub.0.5)(Nb.sub.0.93Sb.sub.0.07)O.sub.3--xBaTiO.sub.3 + 0.5mol%MnO.sub.2 ...system at x = 0.01, 0.02, and 0.04 (KNNS7--xBT) studied over a wide range of temperatures are reported. The observed features of the dielectric nonlinearity at the ferroelectric and structural phase transitions in the materials are described. The dielectric response data of the samples of different contents of the admixture in the KNNS7-xBT ceramics are compared with the behaviour of their elastic properties. Key words: ferroelectrics, relaxors, ceramics, solid solutions, dielectric permittivity, polarization, elastic properties.
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