On the class of graphs with strong mixing properties

We study three mixing properties of a graph: large algebraic connectivity, large Cheeger constant (isoperimetric number) and large spectral gap from 1 for the second largest eigenvalue of the transition probability matrix of the random walk on the graph. We prove equivalence of this properties (in some sense). We give estimates for the probability for a random graph to satisfy these properties. In addition, we present asymptotic formulas for the numbers of Eulerian orientations and Eulerian circuits in an undirected simple graph

Management lag: can social management keep up with high technologies?

The article is devoted to the social management challenges in the digital age. Much attention is paid to the consequences of the high technologies introduction in society, including the “management lag” phenomenon and the issue, whether a society with “smart” technologists absorbed by the ubiquitous digitalisation processes, has time to manage social processes effectively. The relevance of the issue is also determined by the events related with the shift to remote working for many enterprises in the COVID-19 pandemic, during which the world encountered the organising work challenge using information and communication technologies. The functioning of E-Government platforms as one of the innovations examples in social governance in the world is considered in the article through the prism of government programmes of a number of developed countries and relevant statistical data. The Russian and foreign statistical agencies materials, major organisations electronic databases, keeping high-tech development records: Pricewaterhouse Coopers, Boston Consulting Group, United Nations, World Bank, Russian Government, etc., were used for the analysis. It has been concluded that contemporary high-tech society is forced to look for new, efficient governance methods. The management system must be updated to simultaneously meet the social reality demands and keep up with digital changes. Management decision-making processes in an electronic digital society are in the transformation process, and the high technology implementation isues in society are being debated in the scientific community. The digitalisation speed and scale are faster than cultural and managerial development, which is a threat to social progress

Magnetic-field tuning of the spin dynamics in the magnetic topological insulators (MnBi₂Te₄)(Bi₂Te₃₎<i>n</i>

We report a high frequency/high magnetic field electron spin resonance (HF-ESR) spectroscopy study in the sub-THz frequency domain of the two representatives of the family of magnetic topological insulators (MnBi$_{2}$Te$_{4}$)(Bi$_{2}$Te$_{3}$)$_{n}$ with $n = 0$ and 1. The HF-ESR measurements in the magnetically ordered state at a low temperature of $T = 4$ K combined with the calculations of the resonance modes showed that the spin dynamics in MnBi$_{\text{4}}$Te$_{\text{7}}$ is typical for an anisotropic easy-axis type ferromagnet (FM) whereas MnBi$_{\text{2}}$Te$_{\text{4}}$ demonstrates excitations of an anisotropic easy-axis type antiferromagnet (AFM). However, by applying the field stronger than a threshold value $\sim 6$ T we observed in MnBi$_{\text{2}}$Te$_{\text{4}}$ a crossover from the AFM resonance modes to the FM modes which properties are very similar to the ferromagnetic response of MnBi$_{\text{4}}$Te$_{\text{7}}$. We attribute this remarkably unusual effect unexpected for a canonical easy-axis AFM, which, additionally, can be accurately reproduced by numerical calculations of the excitation modes, to the closeness of the strength of the AFM exchange and magnetic anisotropy energies which appears to be a very specific feature of this compound. Our experimental data evidences that the spin dynamics of the magnetic building blocks of these compounds, the Mn-based septuple layers (SLs), is inherently ferromagnetic featuring persisting short-range FM correlations far above the magnetic ordering temperature as soon as the SLs get decoupled either by introducing a nonmagnetic quintuple interlayer, as in MnBi$_{\text{4}}$Te$_{\text{7}}$, or by applying a moderate magnetic field, as in MnBi$_{\text{2}}$Te$_{\text{4}}$, which may have an effect on the surface topological band structure of these compounds

Frequency of Interferon-Resistance Conferring Substitutions in Amino Acid Positions 70 and 91 of Core Protein of the Russian HCV 1b Isolates Analyzed in the T-Cell Epitopic Context

Funding Information: This study was supported by the grant of the Russian Science Foundation (Project ID 15-15-30039). Mobility and training of the researchers was supported by the grants of the Swedish Institute (TP 09272/2013 and PI 19806/2016). Publisher Copyright: © 2018 V. S. Kichatova et al.Amino acid substitutions R70Q/H and L91M in HCV subtype 1b core protein can affect the response to interferon and are associated with the development of hepatocellular carcinoma. We found that the rate of R70Q/H in HCV 1b from Russia was 31.2%, similar to that in HCV strains from Asia (34.0%), higher than that in the European (18.0%, p=0.0010), but lower than that in the US HCV 1b strains (62.8%, p<0.0001). Substitution L91M was found in 80.4% of the Russian HCV 1b isolates, higher than in Asian isolates (43.8%, p<0.0001). Thus, a significant proportion of Russian HCV 1b isolates carry the unfavorable R70Q/H and/or L91M substitution. In silico analysis of the epitopic structure of the regions of substitutions revealed that both harbor clusters of T-cell epitopes. Peptides encompassing these regions were predicted to bind to a panel of HLA class I molecules, with substitutions impairing peptide recognition by HLA I molecules of the alleles prevalent in Russia. This indicates that HCV 1b with R70Q/H and L91M substitutions may have evolved as the immune escape variants. Impairment of T-cell recognition may play a part in the negative effect of these substitutions on the response to IFN treatment.Peer reviewe

Hourly average values of solar wing parameters (flow rate and ion temperatures) according to data of measurements of the Venera-9 and Venera-10 automatic interplanetary stations on an Earth-Venus during the period June 1975 - April 1976

Four electrostatic analyzers with channel electron multipliers as detectors were used to measure solar wind ionic flow. The axes of the fields of vision of two of these analyzers were directed along the axis of the automatic interplanetary station, oriented towards the Sun, while the other two were turned in one plane at angles of +15 deg and -15 deg. The full hemisphere of the angular diagram of each analyzer was approximately 5 deg. The energetic resolution was approximately 6%, and the geometric energy was 0.002 sq cm ave. keV. Each analyzer covered an energetic range of approximately 10 in eight energetic intervals. Spectral distributions were processed in order to obtain the velocity and temperature of the protons. Tabular data show the hour interval (universal time) and the average solar wind velocity in kilometers per second

Changes of photosynthesis and carbon metabolism in typha angustifolia L grown in conditions of nitrate nitrogen overload

Nitrates may induce alterations in NO-signaling system and change photosynthesis in plants. Significant reduction of 14CO 2 fixation was noted at concentration of 3.96 mM NaNO 3 in an aquatic macrophyte (Typha angustifolia L.). Assimilation of 14CO 2 seven days after the introduction of nitrates did not differ between control and experimental samples. There were changes in distribution of 14C among products of 4CO 2 fixation 4 h after NaNO 3 addition, resulting in increased sugar radioactivity in experimental plants. It was suggested that the observed changes may have regulatory importance. © 2012 by Acta Botanica Croatica, the Faculty of Science, University of Zagreb

COMPARATIVE PHARMACOKINETICS AND EFFECT ON THE HEMODYNAMICS OF ORIGINAL AND GENERIC NEBIVOLOL IN HEALTHY VOLUNTEERS

Beta-blockers are an important part of modern pharmacotherapy in cardiology. The introduction of generics into clinical practice requires clear evidence of bioequivalence to the original drug.Aim. To study the pharmacokinetics and effect on hemodynamic parameters of the original and a generic nebivolol in healthy volunteers in the fasting state. Material and methods. 18 healthy volunteers were included into the randomized open study on cross-balanced design. They received single dose (5 mg) of two compared preparations of nebivolol under fasting condition. The concentration of unchanged nebivolol in blood plasma was determined by gas chromatography-tandem mass spectrometry. Calculation of pharmacokinetic parameters and assessment of the hemodynamic were performed.Results. The concentrations of nebivolol after the original and generic drugs intake did not differ significantly in any time point (AUC0-∞ 41.09±46.82 vs 47.16±66.58 ng•hr/mL and T1/2 30.84±10.78 vs 29.59±12.08 hours, respectively). Blood pressure reduction was slightly more pronounced when taking generic nebivolol, while the reduction in heart rate at 2 and 4 hours – after original nebivolol intake.Conclusion. A comparative pharmacokinetic study of the genetic nebivolol showed its bioequivalence to the original drug. The effect on hemodynamic parameters with single dose (5 mg) of generic and original nebivolol in healthy volunteers was comparable