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The results of a one-stage cross-sectional study of the indicators of the psychophysiological state of the body of medical students under 18 years of age and older who have been living for more than 1 year in the Murmansk region (group 1) and new arrivals from other regions of Russia who have been living locally for less than six months (group 2) are presented. The comparative assessment was carried out according to the methods of: C. D. Spielberger in the adaptation of Yu. L. Khanin (situational and personal anxiety); the stress level of Yu. V. Shcherbatykh "Comprehensive assessment of stress manifestations"; the degree of stress tolerance and social adaptation of Holmes–Ray; the degree of neuropsychiatric tension according to the integral indicator of the total deviation from the autogenic norm and the vegetative coefficient, the predominance of the influence of the sympathetic and parasympathetic nervous system on the regulation of adaptation processes and according to the test of M. Lusher's color perception. When compared by age criterion in a group of students aged 18 and older, subjective indicators of psychophysiological state are better than in a group under 18 with an optimal level of neuropsychiatric tension. It is shown that in the group of students living in the Murmansk region for more than one year, the indicators of psychophysiological condition are lower than those of new arrivals. This is expressed by the tension of psycho-emotional and physiological systems, the dominant influence of the sympathetic nervous system on the processes of regulation and the likely breakdown of adaptive mechanisms.

The study investigated the dependences of the structural, magnetic, and optical properties of double manganites NdBaMn2O6 on the degree of order of Nd and Ba atoms in the A-position. Analysis of the temperature dependences of light transmission showed the changes of the charge carrier subsystem in the region of structural and magnetic phase transitions. If there was a metal–insulator transition, the magnetotransmission near the Curie temperature was detected. [ABSTRACT FROM AUTHOR]

Structural, magnetic and optical properties of double manganites PrBaMn2O6 and NdBaMn2O6 are studied depending on the degree of ordering in the A-position. It is shown that, annealing induced disordering goes in an initial stage throw formation of a two-phase state: a phase with a high A-site ordering with TC ∼ 280–300 K and a phase with a low ordering of ~30% with significantly lower TC coexist. In partially ordered PrBaMn2O6 samples there are metal-insulator transitions near TC of the each coexisting phases. In partially ordered NdBaMn2O6 in a highly A-site ordered high-temperature phase, there is no metal-insulator transition due to the destruction of the channels for metallic conductivity formed by the ordering of the x2‒y2 orbitals. If a metal-insulator transition takes place, the application of a magnetic field leads to the effect of magnetotransmission near TC, which is associated with a change in the concentration of delocalized charge carriers. [ABSTRACT FROM AUTHOR]

A comprehensive study of the crystal and electronic structure of TiSe2 intercalated with two 3d metals, Cu and Ni, is presented. It is found that the intercalation of Cu into NixTiSe2 at room temperature leads to the displacement of the Ni atoms from the octahedral to tetrahedral sites with respect to the Se sublattice. This effect is explained by the charge transfer from Cu to the TiSe2-derived conduction band, which makes the chemical bond of Ni with the lattice more stable. This is because the hybridization between Ni 3d and Se 4p, 4s states is stronger than that between Ni 3d and Ti 3d in mono-intercalated NixTiSe2. Therefore, it is possible to control the type of the coordination of the intercalated transition metal atom by changing the concentration of doped electrons. [ABSTRACT FROM AUTHOR]

Powder and single-crystal samples of the high-temperature superconductor Bi2Sr2CaCu2O8 + x are studied by X-ray diffraction. Its thermal expansion coefficient is found to be negative over a wide temperature range (160–260 K). Possible causes of this effect are discussed. [ABSTRACT FROM AUTHOR]

Powder and single-crystal samples of the high-temperature superconductor Bi2Sr2CaCu2O8 + x are studied by X-ray diffraction. Its thermal expansion coefficient is found to be negative over a wide temperature range (160–260 K). Possible causes of this effect are discussed. [ABSTRACT FROM AUTHOR]

We investigate the impacts of sharp variations in solar and geomagnetic activity (GMA) at high latitudes on the human brain bioelectrical activity by means of the empirical structure function of multi-channel EEG. Ten healthy men ages 19 to 37 took part in the study. EEG was recor- ded daily over the 25 days test period that was marked by C- and M-class solar flares and geomagnetic storm levels in the G2-G3 range. The EEG signals were used for the estimate of the mul-tivariate temporal structure function (SF) of the first order in 8-dimensional space. The value of the SF correlation radius is used here as an estimation of a scale of the integral temporal correlation structure of multi-channel EEG, while the value of the SF horizontal asymptote is used as an estimation of the spatial correlation structure of EEG. It is shown that GMA variations make an even greater impact on the SF correlation radius, than on the SF asymptote. We reveal the disturbing and modulating effects of geomagnetic and solar activity on the SF parameters and its power spectrum. Thus, the SF of multi-channel EEG allows us to estimate the effects of heliogeophysical factors on the integrated brain reaction as a unitary system and may be used to investigate the environmental influence on the humans.