Statistical assessment of quality of credit activity of Ukrainian banks

The article conducts an economic and statistical analysis of the modern state of credit activity of Ukrainian banks and main tendencies of its development. It justifies urgency of the statistical study of credit activity of banks. It offers a complex system of assessment of bank lending at two levels: the level of the banking system and the level of an individual bank. The use of the system analysis allows reflection of interconnection between effectiveness of functioning of the banking system and quality of the credit portfolio. The article considers main aspects of management of quality of the credit portfolio – level of troubled debt and credit risk. The article touches the problem of adequate quantitative assessment of troubled loans in the credit portfolios of banks, since the methodologies of its calculation used by the National Bank of Ukraine and international rating agencies are quite different. The article presents a system of methods of management of credit risk, both theoretically and providing specific examples, in the context of prevention of occurrence of risk situations or elimination of their consequences

Cerenkov generation of high-frequency confined acoustic phonons in quantum wells

We analyze the Cerenkov emission of high-frequency confined acoustic phonons by drifting electrons in a quantum well. We find that the electron drift can cause strong phonon amplification (generation). A general formula for the gain coefficient, alpha, is obtained as a function of the phonon frequency and the structure parameters. The gain coefficient increases sharply in the short-wave region. For the example of a Si/SiGe/Si device it is shown that the amplification coefficients of the order of hundreds of 1/cm can be achieved in the sub-THz frequency range.Comment: 4 pages, 2 figures. Submitted to AP

Electron-phonon interaction via Pekar mechanism in nanostructures

We consider an electron-acoustic phonon coupling mechanism associated with the dependence of crystal dielectric permittivity on the strain (the so-called Pekar mechanism) in nanostructures characterized by strong confining electric fields. The efficiency of Pekar coupling is a function of both the absolute value and the spatial distribution of the electric field. It is demonstrated that this mechanism exhibits a phonon wavevector dependence similar to that of piezoelectricity and must be taken into account for electron transport calculations in an extended field distribution. In particular, we analyze the role of Pekar coupling in energy relaxation in silicon inversion layers. Comparison with the recent experimental results is provided to illustrate its potential significance

Hypoxia-inducible factor: basic biology and involvement in cardiovascular pathology

Molecular epidemiological studies conducted to date reveal a close relationship between the polymorphism of the HIF system genes with a wide range of cardiovascular, inflammatory, and oncological diseases. The study of the HIF system can contribute to the discovery of new targets and methods of pharmacological effects for the treatment of cardiovascular, oncological, rheumatological, and endocrinological patholog

Amplification of localized acoustic waves by the electron drift in a quantum well

We have investigated acoustic waves in a heterostructure with a layer embedded into a semiconductor providing acoustic waves localization near the layer and electron confinement inside the layer. For layer thicknesses smaller than wavelengths we have obtained and analyzed the dispersion relation for the localized waves. For electrons into the layer we have supposed that parallel transport is semiclassical, while perpendicular electron motion is quantized. For two-dimensional confined electrons interacting with the acoustic waves we have solved the Boltzmann equation in a parallel electric field. The solutions have been found for electron-phonon interaction via deformation potential. The dispersion relation for coupled charge density and acoustic waves has been analyzed. We have established conditions of amplification of localized acoustic waves under the electron drift for two extreme cases: i) the only lowest two-dimensional subband is populated, ii) a large number of the subbands are populated. We have found that the amplification coefficient of the acoustic waves in THz-rigion is of the order of 100 cm⁻¹. We have discussed the results and compared them with acoustic waves amplification in bulk like semiconductors

The Concept of Ecologically Oriented Progress and Natural Resource Preservation

The most important issue of scientific and technological progress is considering the environment challenges of industrial development. It means that the progress must be ecologically oriented and environmentally friendly. The most adequate concept for the approach to the issue of "man - society – nature" relations is the ontology of the noosphere - the idea of a common space for human beings and nature. It presents an ideal example of an optimistic attitude towards the coordination between accelerating the scientific and technological development and natural resource saving. However, to maintain the balance between human needs and environmental processes determined by this concept, it is essential to include the lean production training into technological development of society

Stimulation of reparation in a linear wound model in rats by Bischofit gel

The article is to evaluate Bischofit gel reparative activity in a linear wound model in rat

Influence of the shape of the particles covering the metal surface on the dispersion relations of surface plasmons

Abstract The Green function method was used for calculation of dispersion relations of surface plasmon generated at the metal surface covered by ellipsoidal particles. The influence of the shape of the particles on the surface plasmon dispersion relations was studied. It was established that both s-and p-polarized surface plasmons can be excited at the surface covered by the particles. It was shown that the shape of the particles covering the surface strongly influences on the surface plasmons dispersion