tt-Martin boundary of killed random walks in the quadrant

We compute the $t$-Martin boundary of two-dimensional small steps random walks killed at the boundary of the quarter plane. We further provide explicit expressions for the (generating functions of the) discrete $t$-harmonic functions. Our approach is uniform in $t$, and shows that there are three regimes for the Martin boundary.Comment: 18 pages, 2 figures, to appear in S\'eminaire de Probabilit\'e

Небезпечна продукція як елемент криміналістичної характеристики злочину, передбаченого ст. 227 КК України

Літвінчук І. С. Небезпечна продукція як елемент криміналістичної характеристики злочину, передбаченого ст. 227 КК України / І. С. Літвінчук // Традиції та новації юридичної науки: минуле, сучасність, майбутнє : матер. Міжнар. наук.-практ. конф. (м. Одеса, 19 трав. 2017 р.). У 2-х т. Т. 2 / відп. ред. Г. О. Ульянова. - Одеса : Видавничий дім "Гельветика", 2017. - С. 775-777

Raman and Infrared-Active Phonons in Hexagonal HoMnO3_3 Single Crystals: Magnetic Ordering Effects

Polarized Raman scattering and infrared reflection spectra of hexagonal HoMnO$_3$ single crystals in the temperature range 10-300 K are reported. Group-theoretical analysis is performed and scattering selection rules for the second order scattering processes are presented. Based on the results of lattice dynamics calculations, performed within the shell model, the observed lines in the spectra are assigned to definite lattice vibrations. The magnetic ordering of Mn ions, which occurs below T$_N$=76 K, is shown to effect both Raman- and infrared-active phonons, which modulate Mn-O-Mn bonds and, consequently, Mn exchange interaction.Comment: 8 pages, 6 figure

A continual model of a damaged medium used for analyzing fatigue life of polycrystalline structural alloys under thermal–mechanical loading

The main physical laws of thermal–plastic deformation and fatigue damage accumulation processes in polycrystalline structural alloys under various regimes of cyclic thermal–mechanical loading are considered. Within the framework of mechanics of damaged media, a mathematical model is developed that describes thermal–plastic deformation and fatigue damage accumulation processes under low-cycle loading. The model consists of three interrelated parts: relations defining plastic behavior of the material, accounting for its dependence on the failure process; evolutionary equations describing damage accumulation kinetics; a strength criterion of the damaged material. The plasticity model based on the notion of yield surface and the principle of orthogonality of the plastic strain vector to the yield surface is used as defining relations. This version of defining equations of plasticity describes the main effects of the deformation process under monotone cyclic, proportional and nonproportional loading regimes. The version of kinetic equations of damage accumulation is based on introducing a scalar parameter of damage degree and energy principles, and account for the main effects of nucleation, growth and merging of microdefects under arbitrary regimes of low-cycle loading. The strength criterion of the damaged material is based on reaching a critical value of the damage degree. The results of numerically modeling cyclic thermal–plastic deformation and fatigue damage accumulation in heat-resistant alloys (Nimonic 80A, Haynes 188) under combined thermal–mechanical loading are presented. Special attention is paid to the issues of modeling the processes of cyclic thermal–plastic deformation and fatigue damage accumulation for complex deformation processes accompanied by the rotation of the main stress and strain tensor areas. It is shown that the present damaged medium model accurately enough for engineering purposes describes the processes of cyclic isothermal and nonisothermal deformation and fatigue damage accumulation under combined thermal–mechanical loading and makes it possible to evaluate low-cycle fatigue life of heat-resistant alloys under arbitrary deformation trajectories

Raman tensor of zinc-phosphide (Zn3P2): from polarization measurements to simulation of Raman spectra

Zinc phosphide (Zn3P2) is a II–V compound semiconductor with promising photovoltaic and thermoelectric applications. Its complex structure is susceptible to facile defect formation, which plays a key role in further optimization of the material. Raman spectroscopy can be effectively used for defect characterization. However, the Raman tensor of Zn3P2, which determines the intensity of Raman peaks and anisotropy of inelastic light scattering, is still unknown. In this paper, we use angle-resolved polarization Raman measurements on stoichiometric monocrystalline Zn3P2 thin films to obtain the Raman tensor of Zn3P2. This has allowed determination of the Raman tensor elements characteristic for the A1g, B1g and B2g vibrational modes. These results have been compared with the theoretically obtained Raman tensor elements and simulated Raman spectra from the lattice-dynamics calculations using first-principles force constants. Excellent agreement is found between the experimental and simulated Raman spectra of Zn3P2 for various polarization configurations, providing a platform for future characterization of the defects in this material

The Near East as a cradle of biodiversity: a phylogeography of banded newts (genus Ommatotriton) reveals extensive inter- and intraspecific genetic differentiation

The banded newt (genus Ommatotriton) is widely distributed in the Near East (Anatolia, Caucasus and the Levant) - an understudied region from the perspective of phylogeography. The genus is polytypic, but the number of species included and the phylogenetic relationships between them are not settled. We sequenced two mitochondrial and two nuclear DNA markers throughout the range of Ommatotriton. For mtDNA we constructed phylogenetic trees, estimated divergence times using fossil calibration, and investigated changes in effective population size with Bayesian skyline plots and mismatch analyses. For nuDNA we constructed phylogenetic trees and haplotype networks. Species trees were constructed for all markers and nuDNA only. Species distribution models were projected on current and Last Glacial Maximum climate layers. We confirm the presence of three Ommatotriton species: O. nesterovi, O. ophryticus and O. vittatus. These species are genetically distinct and their most recent common ancestor was dated at ∼25Ma (Oligocene). No evidence of recent gene flow between species was found. The species show deep intraspecific genetic divergence, represented by geographically structured clades, with crown nodes of species dated ∼8-13Ma (Miocene to Early Quaternary); evidence of long-term in situ evolution and survival in multiple glacial refugia. While a species tree based on nuDNA suggested a sister species relationship between O. vittatus and O. ophryticus, when mtDNA was included, phylogenetic relationships were unresolved, and we refrain from accepting a particular phylogenetic hypothesis at this stage. While species distribution models suggest reduced and fragmented ranges during the Last Glacial Maximum, we found no evidence for strong population bottlenecks. We discuss our results in the light of other phylogeographic studies from the Near East. Our study underlines the important role of the Near East in generating and sustaining biodiversity

РАДІОЗАХИСНІ ВЛАСТИВОСТІ 2-МЕРКАПТОБЕНЗОТІАЗОЛУ НА КЛІТИНИ IN VITRO

Aim: to study the radioprotective properties of 2-merсaptobenzothiazole on proliferating cell culture test system.Material and Methods. Cytological, statistics.Results. Upon the incubation of inoculated cellline L929 with 2-merсaptobenzothiazole in the concentration range 0.03–3.00 µg/mL statistically significant change (p≤0.05) of cell population density in mono layer cultures was not found. At the same time for all the applied reagent concentrations stimulation of mitotic activity in the terminal (5th day) stage of cultivation was observed. Exposure of cells by gamma-quanta of 60Co in doses of 1, 5 and 10 Gyled to dose-dependant morphological changes in cell culture. The irradiation of cells in the presence of 2-mercaptobenzothiazole significantly reduced the negative effect of radiation on the indicators of vitality of cells and their differentiation in culture.Conclusions. Quantitative evaluation of radioprotective properties of 2-mercaptobenzothiazole in the test systems of culture of myogenic cells as well as in the L929 line (fibroblast cells) revealed that the highest coefficients of protection (0.31–0.36) and maximum level of factor of dose reduction (4) were observed at 3 mg/ml reagent concentration (irradiation dose – 1 Gy). According to the literature data and our research results, 2-mercaptobenzothiazole might be considered as a reagent with radioactive properties for cells in vitro.Целью работы было исследование радиопротекторных свойств 2-меркаптобензотиазола в тест-системах первичной и перевиваемой культур пролиферирующих клеток.Материал и методы. Использовали цитологические и статистические методы.Результаты. При инкубации перевиваемых клеток линии L929 с 2-меркаптобензотиазолом в диапазоне концентраций 0,03–3,00 мкг/м не было выявлено статистически достоверного изменения (р≤0,05) плотности клеточной популяции в монослойных культурах. В то же время наблюдали для всех примененных концентраций реагента стимуляцию митотической активности на терминальной (5 сутки) стадии культивирования. Облучение клеток гамма-квантами 60Со в дозах 1, 5 и 10 Гр привело к дозозависимым морфофункциональным изменениям в культуре клеток. Облучение клеток в присутствии 2-меркаптобензотиазола существенно уменьшило негативное влияние радиации на показатели жизнеспособности клеток и их дифференциацию в культуре.Выводы. Количественная оценка радиопротекторных свойств 2-меркаптобензотиазола в тест-системах культуры миогенных клеток и линии L929 (фибробластоподобные клетки) показала, что наивысшие показатели коэффициента защиты (0,31–0,36) реагент показал при концентрации 3 мкг/мл при облучении в дозе 1 Гр, а фактор уменьшения дозы был максимальный – 4, при концентрации 3,00 мкг/мл. По совокупности данных литературы и результатов собственных исследований можно считать 2-меркаптобензотиазол реагентом с радиопротекторными свойствами для клеток in vitro.Метою роботи було дослідження радіопротекторних властивостей 2-меркаптобензотіазолу у тест-системах первинної та перещеплюваної культур проліферуючих клітин.Матеріал і методи. Використовували цитологічні і статистичні методи.Результати. При інкубації перещеплюваних клітин лінії L929 з 2-меркаптобензотіазолом у діапазоні концент­рацій 0,03–3,00 мкг/м не було виявлено статистично достовірної зміни (р≤0,05) щільності клітинної популяції у моношарових культурах. Водночас спостерігали для усіх застосованих концентрацій реагенту стимуляцію мітотичної активності на термінальній (5 доба) стадії культивування. Опромінення клітин гамма-квантами 60Со в дозах 1, 5 та 10 Гр призвело до дозозалежних морфофункціональних змін у культурі клітин. Опромінення клітин у присутності 2-меркаптобензотіазолу істотно зменшило негативний вплив радіації на показники життєздатності клітин та їх диференціацію в культурі.Висновки. Кількісна оцінка радіопротекторних властивостей 2-меркаптобензотіазолу у тест-системах культури міогенних клітин та лінії L929 (фібробластоподібні клітини) показала, що найвищі показники коефіцієнта захисту (0,31–0,36) реагент показав при концентрації 3 мкг/мл при опроміненні в дозі 1 Гр, а фактор зменшення дози був максимальний – 4, за концентрації 3,00 мкг/мл. За сукупністю даних літератури та результатів власних досліджень можна вважати 2-меркаптобензотіазол реагентом із радіопротекторними властивостями для клітин in vitro

Interaction in the Systems with Tl(І), Hg(ІІ), Pb(ІІ), Si(IV).

Методами РФА та ДТА досліджено фазові рівноваги у квазіпотрійних системах Tl2Х–{Hg, Pb}X–SiX2 (X – S, Se). Установлено існування нових тетрарних еквімолярних сполук. Методом порошку розшифровано кристалічну структуру Tl2HgSiSe4 (ПГ I-42m) та Tl2PbSiS4 (ПГ P21/a). The phase equilibria of the quasi-ternary systems Tl 2Х–{Hg, Pb}X–SiX2 (X – S, Se) were investigated by X-ray phase analyse and DTA. New quaternary phases with equil ratio components were found in these systems. Crystal structures of Tl2HgSiSe4 (S. G. I-42m) and Tl2PbSiS4 (S. G. P21/a) were determinated by X-ray powder diffraction