Degeneracy in exotic gravitational lensing

We present three different theoretically foreseen, but unusual, astrophysical situations where the gravitational lens equation ends up being the same, thus producing a degeneracy problem. These situations are (a) the case of gravitational lensing by exotic stresses (matter violating the weak energy condition and thus having a negative mass, particular cases of wormholes solutions can be used as an example), (b) scalar field gravitational lensing (i.e. when considering the appearance of a scalar charge in the lensing scenario), and (c) gravitational lensing in closed universes (with antipodes).The reasons that lead to this degeneracy in the lens equations, the possibility of actually encountering it in the real universe, and eventually the ways to break it, are discussed.Comment: Accepted for publication in Modern Physics Letters

The mathematical simulation of the temperature fields of building envelopes under permanent frozen soil conditions

The physical-mathematical model of the thermal state of the aired technical underground taking into account the air exchange and design features of construction under permanent frozen soil conditions has been suggested. The computational scheme of the temperature fields prediction of building envelopes of projected buildings and soil under and nearby buildings has been developed. The numerical simulation of the temperature fields of building envelopes changes was conducted during a year. The results of the numerical simulation showed that the heat coming from the technical undergrounds and through the walls does not influence the temperature field of the soil neither under a building nor at a distance from it

Improvement of radiopurity level of enriched 116^{116}CdWO4_4 and ZnWO4_4 crystal scintillators by recrystallization

As low as possible radioactive contamination of a detector plays a crucial role to improve sensitivity of a double beta decay experiment. The radioactive contamination of a sample of $^{116}$CdWO$_4$ crystal scintillator by thorium was reduced by a factor $\approx 10$, down to the level 0.01 mBq/kg ($^{228}$Th), by exploiting the recrystallization procedure. The total alpha activity of uranium and thorium daughters was reduced by a factor $\approx 3$, down to 1.6 mBq/kg. No change in the specific activity (the total $\alpha$ activity and $^{228}$Th) was observed in a sample of ZnWO$_4$ crystal produced by recrystallization after removing $\approx 0.4$ mm surface layer of the crystal.Comment: 14 pages, 5 figures and 2 table

Assessment of registered and hidden epidemic process of tick-borne encephalitis in the Republic of Karelia

Introduction. The incidence of tick-borne encephalitis in the Russia remains relevant. The assessment of the epidemic process in the Republic of Karelia is important not only in terms of understanding its general patterns, but in connection with the growth of tourist attendance in the region. Aims: To assess the current epidemic situation of tick-borne encephalitis in the Republic of Karelia, and to compare the characteristics of registered and hidden epidemic processes. Materials and methods. The risk of infection and incidence were estimated based on the analysis of the registered cases of seeking medical help in connection with tick bites, the results of a study of tick-borne encephalitis virus (TBEV) infection rate in ticks, and the epidemiological investigation of cases of tick-borne encephalitis in 1992–2022. Clinical, gender and age structure, territorial distribution of patients and victims of the tick bites were compared with the results of serological studies of 2379 blood samples of the adult population, conducted in 2011–2022. Results. Infection rates of ticks removed from humans ranged from 23.6–27.0% in 2002–2005 to 1.0% in 2022. In 2004, the TBEV antigen was detected in mosquitoes. The territory of risk is the southern part of Republic. However, the increase in number of cases of seeking medical help was observed in the northern part of Republic. The incidence rates exceeded the national average, especially in 2003–2004 (15.3–11.6 per 100 thousand). In 2021–2022, it decreased to 1.8–1.5 per 100,000. The dynamics of incidence had a high-degree correlation with the dynamics of seeking medical help and infection rates in ticks (R = 0.92 and 0.73). The reported incidence was lower than the estimated risk of infection. The meningeal forms of infection were most often diagnosed. The risk of the disease was higher in the elderly and in men, which was determined by the conditions of infection. Antibodies to TBEV were detected in 11.8 ± 0.7% of the examined persons. Conclusion. A steady decrease in rates of registered tick-borne encephalitis incidence has been revealed in the Republic of Karelia, mainly due to the action of biological and natural factors. The assessment of seroprevalence made it possible to reveal the hidden part of the epidemic process

Low-Temperature Mobility of Surface Electrons and Ripplon-Phonon Interaction in Liquid Helium

The low-temperature dc mobility of the two-dimensional electron system localized above the surface of superfluid helium is determined by the slowest stage of the longitudinal momentum transfer to the bulk liquid, namely, by the interaction of surface and volume excitations of liquid helium, which rapidly decreases with temperature. Thus, the temperature dependence of the low-frequency mobility is \mu_{dc} = 8.4x10^{-11}n_e T^{-20/3} cm^4 K^{20/3}/(V s), where n_e is the surface electron density. The relation T^{20/3}E_\perp^{-3} << 2x10^{-7} between the pressing electric field (in kV/cm) and temperature (in K) and the value \omega < 10^8 T^5 K^{-5}s^{-1} of the driving-field frequency have been obtained, at which the above effect can be observed. In particular, E_\perp = 1 kV/cm corresponds to T < 70 mK and \omega/2\pi < 30 Hz.Comment: 4 pages, 1 figur

Research of viscous characteristics of soya lecithin solutions

The viscosity properties of aqueous solutions of soya lecithin, which is a component of dosage forms and has a wide range of functions for a living organism, were studied. The viscometric and pycnometric measurement methods were used in laboratory studies. The study showed that the concentration dependences of the relative viscosity of aqueous solutions of soya lecithin at a concentration not exceeding 2% are described by the Einstein’s equation adjusted for the magnitude and physical meaning of the coefficients. The relative viscosity of such solutions is practically independent of temperature in the range from 8°C to 30°C. The temperature begins to play a significant role in changing the system viscosity at a soya lecithin concentration above 5%. Research results can be used to predict the properties of dosage forms during their storage and application.Изучены вязкостные свойства водных растворов лецитинасоевого, являющегося компонентом лекарственных форм и имеющего широкийспектр функций для живого организма. При лабораторных исследованияхиспользованы вискозиметрический и пикнометрический методы измерений.Показано, что концентрационные зависимости относительной вязкости водных растворов лецитина соевого при концентрации, не превышающей 2%, описываются уравнением Эйнштейна с поправкой на величину и физический смысл коэффициентов. Относительная вязкость таких растворов практически независит от температуры в интервале от 8оС до 30оС. Существенную роль визменении вязкости системы температура начинает играть при концентрации лецитина соевого более 5%. Результаты исследований могут быть использованы для прогнозирования свойств лекарственных препаратов при их хранении и использовании

Anthropometric and functional characteristics of athletes involved in combat sports in the Greco-Roman style

Objective: to determine the morphological and functional parameters of athletes-junior wrestlers, determining their specialization, qualification and training in ontogenesis. Materials and methods: 49 male junior athletes of the school of Olympic reserve engaged in martial arts in the GrecoRoman style for 6-10 years were examined. We used the Dorokhov R.N. (1994) technique of selection and early orientation in sports to determine the anthropometric temporal characteristics. Following functional indicators were determined: absolute and relative physical performance, aerobic performance, power index eagerly, type of vegetative regulation. Results: the majority of fighters teenagers CMS had mesosomal, microcorpulent, micromesomelic, micromesic and mesomacromembral somatotype. A comprehensive study of the functional parameters of the wrestlers showed that indicators of absolute and relative physical performance were higher in young men CMS and were respectively 1318.6±149.5 kg∙m/min and 19.3±2.5 kg∙m/(min∙kg). Aerobic performance was higher in adolescents and first-rank sportsmen: 51.8±9.36 ml/(min∙kg). The strength indices of the hands were higher in the young men's CMS and contributed to 70.6±6.37% for the right hand and 66.08±12.1% for the left hand, which was explained by the component body composition of the body of young men. Most of the wrestlers revealed moderate parasympathicotonia and amphotonic. Conclusions: the R.N. Dorokhova and V.G. Petrukhina (1994) method of somatotyping allows to differentiate athletes, involved in martial arts in the Greco-Roman style, into 3 levels of variation: dimensional, component and proportion and to determine their specialization, qualification and degree of training in ontogenesis

Axially symmetric rotating traversable wormholes

This paper generalizes the static and spherically symmetric traversable wormhole geometry to a rotating axially symmetric one with a time-dependent angular velocity by means of an exact solution. It was found that the violation of the weak energy condition, although unavoidable, is considerably less severe than in the static spherically symmetric case. The radial tidal constraint is more easily met due to the rotation. Similar improvements are seen in one of the lateral tidal constraints. The magnitude of the angular velocity may have little effect on the weak energy condition violation for an axially symmetric wormhole. For a spherically symmetric one, however, the violation becomes less severe with increasing angular velocity. The time rate of change of the angular velocity, on the other hand, was found to have no effect at all. Finally, the angular velocity must depend only on the radial coordinate, confirming an earlier result.Comment: 17 pages, AMSTe

Genotyping of potato samples from the GenAgro ICG SB RAS collection using DNA markers of genes conferring resistance to phytopathogens

Wart (a disease caused by Synchytrium endobioticum) and golden cyst potato nematode (Globodera rostochiensis), which parasitize the roots of the host plant, cause significant damage to potato crop. Both of these disease factors are quarantined in the Russian Federation, and each registered variety is tested for resistance to their most common races and pathotypes. The main method of opposing such diseases is by the development of resistant varieties. An important step in this process is the selection of resistant genotypes from the population and the estimation of the resistance of hybrids obtained by crosses during the breeding process. Conducting a permanent phenotypic evaluation is associated with difficulties, for example, it is not always possible to work with pathogens, and phenotypic evaluation is very costly and time consuming. However, the use of DNA markers linked to resistance genes can significantly speed up and reduce the cost of the breeding process. The aim of the study was to screen the GenAgro potato collection of ICG SB RAS using known diagnostic PCR markers linked to golden potato cyst nematode and wart resistance. Genotyping was carried out on 73 potato samples using three DNA markers 57R, CP113, Gro1-4 associated with nematode resistance and one marker, NL25, associated with wart resistance. The genotyping data were compared with the data on the resistance of the collection samples. Only the 57R marker had a high level of correlation (Spearman R = 0.722008, p = 0.000000, p &lt; 0.05) between resistance and the presence of a diagnostic fragment. The diagnostic efficiency of the 57R marker was 86.11 %. This marker can be successfully used for screening a collection, searching for resistant genotypes and marker-assisted selection. The other markers showed a low correlation between the presence of the DNA marker and resistance. The diagnostic efficiency of the CP113 marker was only 44.44 %. Spearman’s correlation coefficient (Spearman R = –0.109218, p = 0.361104, p &lt; 0.05) did not show significant correlation between resistance and the DNA marker. The diagnostic efficiency of the NL25 marker was 61.11 %. No significant correlation was found between the NL25 marker and resistance (Spearman R = –0.017946, p = 0.881061, p &lt; 0.05). The use of these markers for the search for resistant samples is not advisable