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

Analysis and application of digital spectral warping in analog and mixed-signal testing

Spectral warping is a digital signal processing transform which shifts the frequencies contained within a signal along the frequency axis. The Fourier transform coefficients of a warped signal correspond to frequency-domain 'samples' of the original signal which are unevenly spaced along the frequency axis. This property allows the technique to be efficiently used for DSP-based analog and mixed-signal testing. The analysis and application of spectral warping for test signal generation, response analysis, filter design, frequency response evaluation, etc. are discussed in this paper along with examples of the software and hardware implementation

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

Complementation of two mutant p53: Implications for loss of heterozygosity in cancer

AbstractRemarkably, a cancer cell rarely possesses two mutant p53 proteins. Instead, mutation of one allele is usually associated with loss of the second p53 allele. Why do not two mutant p53 co-exist? We hypothesize that two different p53 may complement each other, when expressed at equal levels. By titrating trans-deficient and DNA-binding-deficient p53 in cells with mutant p53 and by co-transfecting distinct mutant p53 in p53-null cells, we demonstrated activation of p53-dependent transcription. We suggest that, due to complementation of two mutant p53, cancer cells need to delete the second p53 allele rather than mutate it

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

Effect of Drying Mode of Bacterial Biomass on the Effectiveness of Extraction and Physicochemical Properties of the Product (Polymer)

Проведено сравнительное исследование различных режимов высушивания биомассы бактерий Cupriavidus eutrophus В10646. Показано, что различные режимы оказывают влияние на выход конечного продукта (полимера) и его физико-химические свойства (молекулярно-массовые и температурные характеристики). Использование высоких температур приводит к деградации полимера и снижению его молекулярной массы. Применение сублимационной сушки позволяет получить рыхлую биомассу с довольно развитой поверхностью, что благоприятно сказывается на процессе экстракции и не приводит к изменению молекулярно-массовых характеристик полимераComparative study of different drying modes of bacterial biomass of Cupriavidus eutrophus В10646 was conducted. Different modes differently affect the yield of the product (polymer) and its physicochemical properties (molecular weight distribution and temperature characteristics). High temperatures caused the polymer degradation and decrease of its molecular weight. Using freeze drying allows to obtain friable biomass with an extended surface which is favorable for extraction process and to preserve the molecular weight characteristics of the polyme

Localization of the matrix spectrum and Lyapunov type equations

The problems on the location of the matrix spectrum inside or outside domains bounded by ellipses or parabolas are studied. Special Lyapunov-type equations are connected with these problems. Theorems about the unique solvability of such equations are proved. Conditions for perturbations of matrix entries are obtained, which guarantee that the spectra of the perturbed matrices belong to the specified domains as well