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In Russia, in 2007, the Concept of Demographic Policy for the period up to 2025 was developed and approved. One of the key tasks is to increase the birth rate of the population. The measures taken to stimulate the birth rate of the second and subsequent children in the family do not bring the desired result. By 2019, the birth rate in the country again fell to the «pre-reform» level. The article is devoted to the description of the main theories that explain the current situation with the birth rate not only in Russia, but also in the world as a whole: A. Smith’s feedback paradox, the theory of social capillarity by A. Dumont, Caldwell’s theory of flows of goods. The concept of reproductive behavior is considered.

The article reflects the problems of solving theoretical and methodological issues of the statistical research of demographic security. In order to justify the system of statistical indicators of the demographic security, considered regional differences in the incidence of socially significant diseases:tuberculosis, HIV infections, malignant neoplasms, mental disorders, psychotic disorders associated with alcohol use and alcohol dependence syndrome, syphilis. Groups of subjects of the Russian Federation with the maximum and minimum values of indicators are allocated and shown on the map. The most socially prosperous regions in Russia are the Republic of Dagestan, the Chechen Republic, the Republic of Kalmykia, the Republic of Ingushetia and the Belgorod region, the Irkutsk region and the Chukotka Autonomous Okrug were the absolute Champions in terms of social disadvantage in 2018.

Ni@C nanocomposites and the carbon shells extracted by etching Ni@C in nitric acid have been characterized by means of soft X-ray absorption and X-ray photoelectron spectroscopies. It was found on the base of Ni 2p X-ray absorption spectra and atomic multiplet calculations that Ni traces in the carbon-shell sample are in the Ni2+ state formed probably by nickel nitrate hexahydrate, Ni(NO3)2·6H2O. Second derivatives of C 1s of X-ray absorption spectra and C 1s X-ray photoelectron spectra were used for characterization of functional groups linked to carbon shells of nanocomposites. The application of second derivatives of C 1s of X-ray absorption spectra allowed to confirm AA stacking of carbon layers for highly oriented pyrolytic graphite. The low-energy features in C 1s XAS spectra of Ni@C and carbon-shell samples are found to be of a different nature. Most likely, the low-energy C 1s XAS feature of the carbon-shell sample is formed due to hydrogenation of carbon atom.

The method of X-ray absorption spectroscopy has been used for the investigation of charge states of iron ions in iron borate nanoceramics prepared by shear deformation under pressure. The experimental Fe 2p X-ray absorption spectra have been presented in comparison with the calculation of atomic multiplets of iron ions taking into account the charge transfer from the 2p orbitals of oxygen to the 3d orbitals of iron and the crystal-field splitting of the 3d orbitals of iron. Our results indicate that, in addition to iron ions in the ground charge state Fe3+, nanostructured FeBO3 contains a few percent of Fe2+ ions. It has been found that an increase in the degree of plastic deformation (the rotation angle of the anvils) leads to a decrease in the size of crystallites and to an increase in the concentration of Fe2+ ions without the formation of new phases. The results of this work agree with the magnetic and optical measurements and confirm high defectness of FeBO3 nanoceramics.

Results from studying PbS films obtained via pyrolysis of aerosol from solutions of coordination compounds [Pb(N2H4CS)2(CH3COO)2] are presented. The crystal structure of the films is studied. The bandgap of the films, determined from the edge of intrinsic optical absorption, is 0.44–0.51 eV. As the concentration of thiourea rises, the crystallites grow in size and the bandgap shrinks.

Deposition of semiconductor tin and lead sulfide films from thiourea coordination compounds was examined. The nature of the ligands in the intermediate complexes formed was determined, and the influence of these precursors on the formation and phase composition of SnS, SnS2, and PbS thin layers was examined.

New perovskite oxide phases BaCe1 - xInxO3 - x/2 (x = 0.1-0.8) (space group Pbnm) have been synthesized. The unit cell volume of the resulting solid solutions monotonically decreases with an increase in the degree of substitution of indium for cerium due to the contraction of octahedra in perovskite blocks. The thermodynamic stability of the compound BaCe0.75In0.25O2.875 was studied by the solution calorimetry method, and barium cerates were shown to be thermodynamically stable with respect to binary oxides at room temperature. The structure of occupied and vacant states in BaCe1 - xInxO3 - x/2 was determined on the basis of Xray emission, absorption, and photoelectron spec tra, and the energy gap was estimated at ~2 eV.

The electronic properties of a series of colossal magnetoresistance (CMR) compounds, namely LaMnO3, La(1-x)Ba(x)(MnO3 (0.2or = xor = 0.55), La(0.76)Ba(0.24)Mn(0.84)Co(0.16)O3, and La(0.76)Ba(0.24)Mn(0.78)Ni(0.22)O3, have been investigated in a detailed spectroscopic study. A combination of X-ray photoelectron spectroscopy (XPS), X-ray emission spectroscopy (XES), X-ray absorption spectroscopy (XAS), and resonant inelastic X-ray scattering (RIXS) was used to reveal a detailed picture of the electronic structure in the presence of Ba, Co, and Ni doping in different concentrations. The results are compared with available theory. The valence band of La(1-x)()Ba(x)MnO3 (0or = xor = 0.55) is dominated by La 5p, Mn 3d, and O 2p states, and strong hybridization between Mn 3d and O 2p states is present over the whole range of Ba concentrations. Co-doping at the Mn site leads to an increased occupancy of the e(g) states near the Fermi energy and an increase in the XPS valence band intensity between 0.5 and 5 eV, whereas the Ni-doped sample shows a lower density of occupied states near the Fermi energy. The Ni d states are located in a band spanning the energy range of 1.5-5 eV. XAS spectra indicate that the hole doping leads to mixed Mn 3d-O 2p states. Furthermore, RIXS at the Mn L edge has been used to probe d-d transitions and charge-transfer excitations in La(1-x)Ba(x)MnO3.

The integrated-intensity ratio R of the Lβ and Lα lines in x-ray emission spectra of 3d transition metal oxides was measured. The magnitude of the ratio was found to depend nonmonotonically on the atomic number of the 3d elements, with a sharp rise in the middle of the series. In terms of the theory of one-electron resonant x-ray scattering in a solid, a simple relation was derived connecting this ratio with the spin polarization of occupied and empty d states. The calculated values of R qualitatively reflect the behavior of the measured I(Lβ)/I(Lα) ratio on the atomic number of 3d elements. Thus, the existence of a dependence of the integrated-intensity ratio of Lβ and Lα lines on the atomic magnetic moment has been established. All calculated R curves lie above the I(Lβ)/I(Lα)exp data, because not all factors accompanying the x-ray emission process were included in the calculation.

This paper reports on a study of the magnetic susceptibility, x-ray photoelectron, and x-ray emission spectra of the LiCoO2−δ and NaxCoO2 nonstoichiometric oxides. The valence-band structure of LiCoO2 was analyzed. The hole concentration in the oxygen 2p band of LiNiO2 and LiCoO2 was derived from measurements of the O Kα emission spectra. Measurements of Co 2p and Co 3s photoelectron spectra showed that the Co3+ ions reside in the low-spin state with S=0. The deficiency of oxygen in the LiCoO2−δ reduced oxides gives rise to the formation of divalent cobalt ions. The deficiency of the alkali metal in NaxCoO2 initiates the formation of holes in the oxygen 2p band while not changing the electronic configuration d 6 of the cobalt-ion ground state.

The electronic structure of the doped perovskite manganese oxides La1-x Srx MnO3 and La1xBax MnO3 has been investigated by X-ray photoelectron and X-ray emission spectroscopy. By comparing the O Kα and Mn Lα X-ray emission spectra with the valence band X-ray photoelectron spectra we could localize the Mn 3d and O 2p states into the valence band. Our data are compared with previous band structure calculations. The value of the Mn 3s splitting does not change with Sr-doping in the concentration region from x = 0.0 till x = 0.3. This shows that the doping holes have mainly oxygen p character. The large value of the splitting indicates that the 3d electrons are in the high-spin state.

The electronic structure of LiMnO2 and Li2MnO3 was studied by means of X-ray photoelectron and soft X-ray emission spectroscopy. For LiMnO2, LSDA and LSDA+U calculations were carried out. The LSDA+U calculations are in rather good agreement with the measured valence-band structure as well as with the magnetic and electrical properties of LiMnO2. It is shown that the band gap in LiMnO2 is determined by the charge-transfer effect.

The results of measurements of X-ray photoelectron spectra (valence band and core levels), the O 1s X-ray absorption spectra and fluorescence X-ray emission valence spectra (O K α and Mn L 2,3 ) near the O 1s and the Mn 2p threshold of EuMnO 3 and Eu 0.7 Ca 0.3 MnO 3 are presented. They are compared with LSDA and LDA+U band structure calculation of orthorhombic and cubic LaMnO 3 . Comparison of XPS valence band spectra and O K α and Mn L 3 X-ray emission spectra with band structure calculations shows that the LSDA is more accurate than the LDA+U approach as a description of the spectroscopic properties of orthorhombic EuMnO 3 .

The results of measurements of O $1s$ total x-ray-fluorescence yield and Ru ${N}_{2,3}$ and O ${K}_{\ensuremath{\alpha}}$ x-ray fluorescence emission spectra of ${\mathrm{Sr}}_{2}{\mathrm{RuO}}_{4}$ and ${\mathrm{Sr}}_{2}{\mathrm{RuO}}_{4.25}$ are presented. An excitation energy dependence of the O ${K}_{\ensuremath{\alpha}}$ x-ray emission spectra (XES) was observed in both compounds. The energy dependence of the spectra is attributed to the excitation of inequivalent O (1) in-plane and O(2) apical oxygens. The O(1) $2p$ and O(2) $2p$ density of states distribution in the valence band of ${\mathrm{Sr}}_{2}{\mathrm{RuO}}_{4}$ was found to be different in accordance with the results of band-structure calculations. O(1) $2p$ states are found to be mixed with Ru ${4d(t}_{2g})$ states providing the formation of $\ensuremath{\pi}$ bonds. While the O ${K}_{a}$ XES spectra are in fair agreement with band structure calculations, the theoretical two-peak distribution of Ru ${N}_{2,3}$ XES is found to be different with respect to the intensity ratios and widths of the peaks of Ru ${N}_{2,3}$ XES. These differences are attributed to a decrease of intensity of radiative $4\stackrel{\ensuremath{\rightarrow}}{d}4p$ transitions in the vicinity of the Fermi level (where the localization of Ru $4d$ states is higher than at the bottom of the valence band) due to a strong Koster-Kronig transition.

Electronic structure of nickel nanoparticles encapsulated in carbon was characterized by photoelectron, X-ray absorption, and X-ray emission spectroscopies. Experimental spectra are compared with the density of states calculated in the frame of the density functional theory. The carbon shell of Ni nanoparticles has been found to be multilayer graphene with significant (about 6%) amount of Stone--Wales defects. Results of the experiments evidence protection of the metallic nanoparticles from the environmental degradation by providing a barrier against oxidation at least for two years. Exposure in air for 2 years leads to oxidation only of the carbon shell of Ni@C nanoparticles with coverage of functional groups., Comment: 16 pages, 6 figures, accepted in J. Phys. Chem. C

X-ray absorption, resonant x-ray emission, and x-ray photoelectron spectra of the valence band and core levels have been measured for LixCoO2 (0.6

We present Mn $3s$ x-ray photoelectron spectra of manganese oxides with the Mn formal valency from $2+$ to $4+.$ We found that the ${\mathrm{Sr}}^{2+}$ doping or cation deficiency in manganites do not change the Mn $3s$ splitting in manganites with the Mn formal valency from $3.0+$ to $3.3+.$ We suggest that doping holes are localized in O $2p$ states.

Four hundred and forty pediatric patients at the age of 7 days to 15 years with various infections admitted to the Hospital within a month were examined. The biological material was inoculated to blood agar on the first days of the patient admittance to the Hospital and after the growth the organisms were isolated and identified. Antibiotic susceptibility of the isolates was assayed with the disk diffusion method. 479 strains in all were tested. The most frequent cases requiring hospitalization and antibiotic therapy were those of respiratory tract infections (54.09 per cent), urinary tract infections (26.36 per cent), cutaneous and subcutaneous fat diseases, gastrointestinal diseases and others (about 25 per cent of the cases in all). The main pathogens were Streptococcus viridans, S.aureus and S.epidermidis, as well as Enterobacteriaceae (chiefly E.coli) whose frequencies were practically equal (in 25-35 per cent of the cases). The Pneumococcus isolates amounted to 6.3 per cent. Nonfermenting bacteria (Pseudomonas aeruginosa and Acinetobacter) and some representatives of Enterobacteriaceae (Citrobacter, Serratia, Morganella) were isolated from 7 per cent of the patients. The frequency of Klebsiella and Enterobacter was about 11 per cent. The main pathogens were tested for their susceptibility to amoxycillin/clavulanic acid, ampicillin, oxacillin and gentamicin. The least active antibiotic was ampicillin. 88.8 per cent of the E.coli isolates and 100 per cent of the Klebsiella, P.mirabilis, Morganella, Citrobacter, Enterobacter and Serratia isolates were resistant to it. 53.2 per cent of the Streptococcus isolates including 64.5 per cent of the Pneumococcus isolates were as well resistant to ampicillin. 59.5 per cent of the Streptococcus isolates (mainly S.viridans and Enterococcus) was susceptible to oxacillin, 22.2 per cent of them being moderately susceptible. 62.5 per cent of the Pneumococcus isolates and 78.1 per cent of the Staphylococcus isolates were also susceptible to oxacillin. The highest susceptibility of the isolates was that to amoxycillin/clavulanic acid, i.e. 90.1 per cent of the strains, 79.9 per cent of them being highly susceptible. All the isolates of Citrobacter, Serratia and Morganella and some isolates of P.aeruginosa, Acinetobacter, Enterobacter, Klebsiella and E.coli were resistant to amoxycillin/clavulanic acid. As for the latter 5 organisms their susceptibility to amoxycillin/clavulanic acid was comparable with that to gentamicin. The susceptibility of the Streptococcus and Staphylococcus isolates to amoxycillin/clavulanic acid was significantly much higher than that to oxacillin, gentamicin and ampicillin: 93 per cent of the Streptococcus isolates (62.7 per cent of the Pneumococcus isolates) and 90.7 per cent of the Staphylococcus isolates.