On the maximum size of a minimal k-edge connected augmentation

AbstractWe present a short proof of a generalization of a result of Cheriyan and Thurimella: a simple graph of minimum degree k can be augmented to a k-edge connected simple graph by adding ⩽knk+1 edges, where n is the number of nodes. One application (from the previous paper) is an approximation algorithm with a guarantee of 1+2k+1 for the following NP-hard problem: given a simple undirected graph, find a minimum-size k-edge connected spanning subgraph. For the special cases of k=4,5,6, this is the best approximation guarantee known

The Simulation of Infrasound Propagation During Volcanic Eruptions

Розглянуто інфразвук у якості ключового параметра під час реєстрації природних та техногенних катастроф. Проведено моделювання інфразвукових характеристик у разі виверження вулканів. Підкреслюється необхідність посилення ролі систем моніторингу у дослідженнях вулканічних інфразвуковых характеристик у разі вивержения вулканів. Необхідно посилити призначення системи моніторінгу у дослідженнях вулканчних вивердженнях шляхом реєстрації інфразвука.The simulation of infrasound propagation during volcanic eruptions is considered. Infrasound is considered as a factor of the informative parameter in volcanic eruptions recording. A factor that has a significant effect on the infrasound in the atmosphere is the seismic activity. And it can be an external influence on the preparatory processes and their result. About fifty percent of infrasound is thrown into the atmosphere in the blast wave form. Such impulses spread to many kilometers from the source in the sound wave form. Their damping depends primarily on the frequency. Eruptions monitoring of active volcanoes by remote methods is very important for ensuring the safety of aviation flights. One of the remote methods for monitoring volcanic ash is the infrasound method, since strong eruptions are accompanied by wave perturbations in the atmosphere recorded over long distances. It is necessary to investigate how the sound power, its intensity and sound pressure level change with volcanic eruptions. To simulate the infrasonic waves propagation during volcanic eruption an algorithm and a program are composed. The program is written on Java programming language and consists of individual generated cycles. Calculations are performed assuming that the atmosphere with the infrasonic waves propagation, is homogeneous, layers are absent, the temperature is 20 degrees Celsius, and the sound velocity in the air in this case is 340 m / s. Acoustic waves attenuation in the air is caused by the presence of shear and bulk viscosity and also thermal conductivity impact. If we neglect the thermal losses, and also take into account that the bulk viscosity must be taken into account, as a rule, for high frequencies, then we can assume that the propagation loss of the traveling wave in the real environment results from the shear viscosity. The aim of this work is the infrasound propagation simulating during volcanic eruptions by the program complex. Currently, there is a great need for the creation of systems that combine space and ground-based observations that accurately capture key climate variables and stable functioning for several decades to determine climate variability and trends. The method of interaction studies of space weather, natural and manmade disasters with the organisms of the noosphere of the Earth through the registration of infrasound is proposed. Algorithms and software for calculations of acoustic infrasound field characteristics and decay in the atmosphere are developed. It was found that when r = 5λ phase shift between the sound pressure and vibrational velocity in the far field can be neglected and they are considered to be in phase. The results of these calculations confirmed that for the infrasonic wave propagation in the air the counting of viscous friction is not produced. With the help of modern computers, it is possible to calculate the infrasonic waves movement in the atmosphere and use this information to predict volcanic eruptions.Рассмотрен инфразвук в качестве ключевого параметра при регистрации природных и техногенных катастроф. Проведено моделирование инфразвуковых характеристик при извержениях вулканов. Подчеркивается необходимость усиления роли систем мониторинга в исследованиях вулканических инфразвуковых характеристик при извержениях вулканов. Подчеркивается необходимость усиления роли систем мониторинга в исследованиях вулканических извержений путем регистрации инфразвука извержений путем регистрации инфразвука

Emerging giant resonant exciton induced by Ta-substitution in anatase TiO2_{2}: a tunable correlation effect

Titanium dioxide (TiO$_2$) has rich physical properties with potential implications in both fundamental physics and new applications. Up-to-date, the main focus of applied research is to tune its optical properties, which is usually done via doping and/or nano-engineering. However, understanding the role of $d$-electrons in materials and possible functionalization of $d$-electron properties are still major challenges. Herewith, within a combination of an innovative experimental technique, high energy optical conductivity, and of the state-of-the-art {\it ab initio} electronic structure calculations, we report an emerging, novel resonant exciton in the deep ultraviolet region of the optical response. The resonant exciton evolves upon low concentration Ta-substitution in anatase TiO$_{2}$ films. It is surprisingly robust and related to strong electron-electron and electron-hole interactions. The $d$- and $f$- orbitals localization, due to Ta-substitution, plays an unexpected role, activating strong electronic correlations and dominating the optical response under photoexcitation. Our results shed light on a new optical phenomenon in anatase TiO$_{2}$ films and on the possibility of tuning electronic properties by Ta substitution

UV-VUV synchrotron radiation spectroscopy of NiWO₄

Photoluminescence and excitation spectra of microcrystalline and nanocrystalline nickel tungstate (NiWO₄) were measured using UV-VUV synchrotron radiation source. The origin of the bands is interpreted using comparative analysis with isostructural ZnWO₄ tungstate and based on the results of recent first-principles band structure calculations. The influence of the local atomic structure relaxation and of Ni²⁺ intra-ion d–d transitions on the photoluminescence band intensity are discussed

PATHOMORPHOLOGICAL CHANGES IN LIVER OF WHITE MICE AT EXPERIMENTAL PLAGUE INFECTION CAUSED BY YERSINIA PESTIS OF DIFFERENT PLASMID COMPOSITION

Data of histological study of pathomorphological changes in liver of white mice with experimental plague are represented in the article. An important element in evaluation and prediction of the pathological process in the liver is the analysis of hepatocyte karyokinesis, the mitotic index calculation, the counting number of atypical mitosis and the degree of organ regeneration ability. Dynamics of these liver changes at infection process in experimental animals caused by Yersinia pestis plasmid variants was investigated in this work. The variability of liver injuries was shown depending on plasmid-associated virulence of the infection agent. It was proved that the Y. pestis strain carrying three basic pYP (6 mDa), pYV (45 mDa), pYT (61 mDa) plasmids caused the most severe systemic disease with lethal outcome as a rule. Lack of species-specific plasmids and especially virulence and pathogenicity plasmids reduced the rate of infection process generalization and the ability of the pathogen to initiate pathological changes incompatible with the microorganism life. Therefore, all morphological liver changes in experimental plague infection are directly dependent on plasmid profile of the pathogen. The mechanism of toxicity included the damaging effect of the toxin to the cellular structures and failure of the metabolic processes in the organism. Acuity of intoxication and the development of pathological process can be estimated by exploring changes in liver morphology

COMPARATIVE CHARACTERISTICS OF IMMUNOLOGICAL RECONSTRUCTION OF WHITE MICE IMMUNIZED BY CELL WALL OF DIFFERENT SUBSPECIES OF FRANCISELLA TULARENSIS

At present, development of effective vaccines of new generation is an actual problem, in particular concerning the tularemia causative agent. It determines the need to search antigen determinants with high immunogenic activity. Some authors demonstrate that outer membrane proteins of Francisella tularensis possess immunological activity. This fact gave occasion to isolation and comprehensive study of F tularensis cellular envelopes as a perspective component in vaccine engineering. The influence of cell walls of F. tularensis was studied for morphological changes in immunocompetent organs of experimental animals. Cell walls were obtained from three virulence strains of living cultures: F. tularensis subsp. mediaasiatica А-61, F. tularensis subsp. nearctica В-399 A-Cole, F. tularensis subsp. holarctica 306 and vaccine strain F. tularensis subsp. holarctica 15 (extracted by Research Institute of Epidemiology and Hygiene). Cell walls of different subspecies of F. tularensis stimulate the production of antibody forming cells and cell proliferation more in T-dependent zones of lymph nodes and spleen. It has been determined that these antigen preparations do not cause stress reaction of the experimental animal organisms. Basing on the findings, we made a conclusion that there is a need for further detailed investigation of immunogenic properties of CE F. tularensis subsp. holarctica 306, F. tularensis subsp. mediasiatica А-61 and F. tularensis subsp. tularensis B-399 A-Cole as perspective components in development of tularemia vaccines

Giant penile melanoma

Primary penile melanoma is an extremely rare casuistic pathology associated with a poor prognosis. The article presents a clinical case of massive lesion of the penis with malignant melanoma, and discusses surgical methods for treating this pathology

The use of platelet-rich plasma (PRP) in urology

Platelet-rich plasma (PRP) is one of the most common and practicable plasma-therapy techniques. The wide therapeutic range for the use of this technique in various medical fields is due to its high content of growth factors, cytokines, and chemokines. The property of PRP to induce tissue regeneration is particularly highlighted, which is used actively for the treatment of a broad range of urological diseases. The review aimed to highlight the accumulated material on the topic of the use of autologous biomaterials based on blood in urology. This article highlights the urgent need for further study of the prospects for the use of autoplasma technologies in wide multicenter studies