Ordering of small particles in one-dimensional coherent structures by time-periodic flows

Small particles transported by a fluid medium do not necessarily have to follow the flow. We show that for a wide class of time-periodic incompressible flows inertial particles have a tendency to spontaneously align in one-dimensional dynamic coherent structures. This effect may take place for particles so small that often they would be expected to behave as passive tracers and be used in PIV measurement technique. We link the particle tendency to form one-dimensional structures to the nonlinear phenomenon of phase locking. We propose that this general mechanism is, in particular, responsible for the enigmatic formation of the `particle accumulation structures' discovered experimentally in thermocapillary flows more than a decade ago and unexplained until now

An improvement of the Berry--Esseen inequality with applications to Poisson and mixed Poisson random sums

By a modification of the method that was applied in (Korolev and Shevtsova, 2009), here the inequalities $$\rho(F_n,\Phi)\le\frac{0.335789(\beta^3+0.425)}{\sqrt{n}}$$ and $$\rho(F_n,\Phi)\le \frac{0.3051(\beta^3+1)}{\sqrt{n}}$$ are proved for the uniform distance $\rho(F_n,\Phi)$ between the standard normal distribution function $\Phi$ and the distribution function $F_n$ of the normalized sum of an arbitrary number $n\ge1$ of independent identically distributed random variables with zero mean, unit variance and finite third absolute moment $\beta^3$. The first of these inequalities sharpens the best known version of the classical Berry--Esseen inequality since $0.335789(\beta^3+0.425)\le0.335789(1+0.425)\beta^3<0.4785\beta^3$ by virtue of the condition $\beta^3\ge1$, and 0.4785 is the best known upper estimate of the absolute constant in the classical Berry--Esseen inequality. The second inequality is applied to lowering the upper estimate of the absolute constant in the analog of the Berry--Esseen inequality for Poisson random sums to 0.3051 which is strictly less than the least possible value of the absolute constant in the classical Berry--Esseen inequality. As a corollary, the estimates of the rate of convergence in limit theorems for compound mixed Poisson distributions are refined.Comment: 33 page

Antioxidative Activity of Ferrocenes Bearing 2,6-Di-Tert-Butylphenol Moieties

The antioxidative activity of ferrocenes bearing either 2,6-di-tert-butylphenol or phenyl groups has been compared using DPPH (1,1-diphenyl-2-picrylhydrazyl) test and in the study of the in vitro impact on lipid peroxidation in rat brain homogenate and on some characteristics of rat liver mitochondria. The results of DPPH test at 20°C show that the activity depends strongly upon the presence of phenolic group but is improved by the influence of ferrocenyl fragment. The activity of N-(3,5-di-tert-butyl-4-hydroxyphenyl)iminomethylferrocene (1), for instance, was 88.4%, which was higher than the activity of a known antioxidant 2,6-di-tert-butyl-4-methylphenol (BHT) (48.5%), whereas the activity of N-phenyl-iminomethylferrocene 2 was almost negligible −2.9%. The data obtained demonstrate that the compounds with 2,6-di-tert-butylphenol moiety are significantly more active than the corresponding phenyl analogues in the in vitro study of lipid peroxidation in rat brain homogenate. Ferrocene 1 performs a promising behavior as an antioxidant and inhibits the calcium-dependent swelling of mitochondria. These results allow us to propose the potential cytoprotective (neuroprotective) effect of ditopic compounds containing antioxidant 2,6-di-tert-butylphenol group and redox active ferrocene fragment

Phase separation in iron chalcogenide superconductor Rb0.8+xFe1.6+ySe2 as seen by Raman light scattering and band structure calculations

We report Raman light scattering in the phase separated superconducting single crystal Rb0.77Fe1.61Se2 with Tc = 32 K. The spectra have been measured in a wide temperature range 3K -500K. The observed phonon lines from the majority vacancy ordered Rb2Fe4Se5 (245) antiferromagnetic phase with TN= 525 K demonstrate modest anomalies in frequency, intensity and halfwidth at the superconductive phase transition. We identify phonon lines from the minority compressed Rb{\delta}Fe2Se2 (122) conductive phase. The superconducting gap with dx2-y2 symmetry is also detected in our spectra. In the range 0-600 cm-1 we observed the low intensive but highly polarized B1g-type background which becomes well structured under cooling. The possible magnetic or multiorbital origin of this background has been discussed. We argue that phase separation in M0.8+xFe1.6+ySe2 has pure magnetic origin. It occurs below Neel temperature when iron magnetic moment achieves some critical magnitude. We state that there is a spacer between the majority 245 and minority 122 phases. Using ab-initio spin polarized band structure calculations we demonstrate that compressed vacancy ordered Rb2Fe4Se5 phase can be conductive and therefore may serve as a protective interface spacer between the pure metallic Rb{\delta}Fe2Se2 phase and the insulating Rb2Fe4Se5 phase providing the percolative Josephson-junction like superconductivity in the whole sample of Rb0.8+xFe1.6+ySe2 Our lattice dynamics calculations show significant difference in the phonon spectra of the conductive and insulating Rb2Fe4.Se5 phases.Comment: This paper is devoted to the memory of academician Kirill Borisovich Tolpygo, prominent Physicist, Teacher and Citizen, who made a great contribution to the lattice dynamics theory and many other branches of solid state physic

Белково-липидный состав пыльцы березы бородавчатой (Betula verrucosa) и ее антиоксидантная активность в зависимости от места произрастания

Pollen has various effects on the human body. In order to study and compare the biological activity of the mature pollen grains of Betula verrucosa Ehrh. we investigated the protein-lipid composition and total antioxidant activity (TAA) of 10 samples from different habitats in the territory of Ukraine and the Slovak Republic. The collection sites are near highways and apartment blocks, as well as a nature reserve, forest and botanical garden. The protein content was determined by the Kjeldahl method. A chromatographic analysis of fatty acids from lipids was performed using a “Cvet 500” gas chromatograph, equipped with a flame-ionization detector in the isothermal mode. The bioactivity of aqueous, ethanol and methanol extracts of pollen grains was evaluated by the DPPH free radical scavenging method (2,2-diphenyl-1-picrylhydrazyl) by means spectrophotometry in vitro. The protein content of the pollen of B. verrucosa ranged from 17.9% to 25.6%, depending on the habitat. Unsaturated fatty acids were found in higher amounts than saturated fatty acids. The profile of fatty acids indicates a higher content of palmitic (33.9%), oleic (29.5%) and linoleic (27.8%) acids and a low content of arachidonic (0.4%) and pentadecanoic (0.8%) acids. We also established that silver birch pollen is characterized by high antioxidant activity. The measured value of TAA for aqueous pollen extracts was within 74.8–85.5%. For the ethanol extracts it was quantified within 60.3–95.0% and for the methanol extracts – 46.1–92.6%. The Tukey test was used to determine the differences between the means at a level of P &lt; 0.05. A strong correlation coefficient (0.70) was defined between the protein content and the TAA of aqueous extracts. In general, the Ukrainian and Slovak samples of pollen differ in the fatty acid composition of lipids and aqueous and ethanol TAA extracts. Pollen of B. verrucosa should be used for diagnostic, therapeutic and prophylactic purposes as close as possible to the place of origin. Исследованы белковый и липидный состав и биологическая активность 10 образцов пыльцы Betula verrucosa Ehrh. из разных мест произрастания на территории Украины и Словакии. Определено содержание белков (17,9–25,6%) и 8 жирных кислот (с числом углеродных атомов от 14 до 20) в составе липидов. Выявлено преобладание ненасыщенных жирных кислот (58,6%) с доминированием пальмитиновой (33,9%), олеиновой (29,5%) и линолевой (27,8%). Оценена общая антиоксидантная активность водных, этаноловых и метаноловых экстрактов пыльцы березы бородавчатой с использованием свободного стабильного радикала дифенил­пикрилгидразила колориметрически в реакции in vitro. Установлены статистически достоверные различия между образцами как внутри украинских и словацких генотипов, так и между ними. Рассматриваются факторы влияния на вариации белково-липидного состава пыльцы и ее биологической активности.Исследованы белковый и липидный состав и биологическая активность 10 образцов пыльцы Betula verrucosa Ehrh. из разных мест произрастания на территории Украины и Словакии. Определено содержание белков (17,9–25,6%) и 8 жирных кислот (с числом углеродных атомов от 14 до 20) в составе липидов. Выявлено преобладание ненасыщенных жирных кислот (58,6%) с доминированием пальмитиновой (33,9%), олеиновой (29,5%) и линолевой (27,8%). Оценена общая антиоксидантная активность водных, этаноловых и метаноловых экстрактов пыльцы березы бородавчатой с использованием свободного стабильного радикала дифенил­пикрилгидразила колориметрически в реакции in vitro. Установлены статистически достоверные различия между образцами как внутри украинских и словацких генотипов, так и между ними. Рассматриваются факторы влияния на вариации белково-липидного состава пыльцы и ее биологической активности

МЕТОДЫ ОПРЕДЕЛЕНИЯ ПОТОКА НАСЫЩЕНИЯ АВТОТРАССЫ

The article reviews the methods, used in Russia to determine saturation flow while computing regime of traffic lights regulation for city motor roads. The authors have suggested a new tool of mathematical assessment of the desired quantity in order to achieve better quality of road signal regulation. The proposed method of determination of saturation flow as compared to classical and foreign methods, allows to take into account a larger number of parameters and to achieve a more exact result.The researchers have also tested the innovation model by using it at real street intersection and organized implementation of the study results in the framework of cooperation with municipal administration of the city of Belgorod. The study has shown that the optimum regime of traffic lights operation reduces car delays by 15–25%.Рассмотрены используемые в стране методы определения потока насыщения при расчете режима работы светофорного регулирования на автомобильных трассах города. Предложен новый способ математической оценки искомой величины с целью улучшения качества дорожной сигнализации. Осуществлена проверка инновационной модели на реально существующем уличном пересечении и организовано внедрение полученного результата в рамках взаимодействия с муниципальными структурами Белгорода.