Rocking Subdiffusive Ratchets: Origin, Optimization and Efficiency

We study origin, parameter optimization, and thermodynamic efficiency of isothermal rocking ratchets based on fractional subdiffusion within a generalized non-Markovian Langevin equation approach. A corresponding multi-dimensional Markovian embedding dynamics is realized using a set of auxiliary Brownian particles elastically coupled to the central Brownian particle (see video on the journal web site). We show that anomalous subdiffusive transport emerges due to an interplay of nonlinear response and viscoelastic effects for fractional Brownian motion in periodic potentials with broken space-inversion symmetry and driven by a time-periodic field. The anomalous transport becomes optimal for a subthreshold driving when the driving period matches a characteristic time scale of interwell transitions. It can also be optimized by varying temperature, amplitude of periodic potential and driving strength. The useful work done against a load shows a parabolic dependence on the load strength. It grows sublinearly with time and the corresponding thermodynamic efficiency decays algebraically in time because the energy supplied by the driving field scales with time linearly. However, it compares well with the efficiency of normal diffusion rocking ratchets on an appreciably long time scale

Three-body treatment of the penetration through the Coulomb field of a two-fragment nucleus

On the basis of the Faddeev integral equations method and the Watson- Feshbach concept of the effective (optical) interaction potential, the first fully consistent three-body approach to the description of the penetration of a charged particle through the Coulomb field of a two-particle bound complex (composed of one charged and one neutral particles) has been developed. A general formalism has been elaborated and on its basis, to a first approximation in the Sommerfeld parameter, the influence of the nuclear structure on the probability of the penetration of a charged particle (the muon, the pion, the kaon and the proton) through the Gamow barrier of a two-fragment nucleus (the deuteron and the two lightest lambda hypernuclei, lambda hypertriton and lambda hyperhelium-5, has been calculated and studied.Comment: LaTeX, 30 pages, 4 eps figure

Assessing Software Vulnerabilities and Recovery Time Using Open Resources: Elements Of Technique And Results

Modern vulnerability resources are considered, their content security and recovery time of different software products are analyzed. To make the process smoother and more efficient three main stages are distinguished: source overview, general security and severity analysis, and more detailed vulnerability consideration including recovery time. The proposed approach is universal and can be used almost for any software projects and systems

Класифікація ЕКГ сигналів методами машинного навчання

The importance of electrocardiogram (ECG) analysis is difficult to overestimate. Rhythm of life, stress and other factors affect the frequency of diseases and their early appearance. At the same time, the technologization (digitalization) of life and hardware-software complexes, such as mobile electronic cardiographs and wearable devices in general, which are rapidly developing, open new opportunities for rapid analysis of human state by certain indicators, as well as allow to diagnose on the new higher level in almost real time. There are many methods for analyzing cardiograms. In this paper, the authors propose a new approach based on an ensemble of individual classifiers, which effectively solves the problem of ECG analysis. The study is based on the PhysioNet Computing in Cardiology Challenge 2017 and the MIT-BIH Arrhythmia Database. The algorithm consists of the following stages: data filtering using moving average and Butterworth filters, R-peak localization via threshold and grouping method, ECG resampling for the better comparability, “Noisy” vs “NotNoisy” classification as the most hard-to-identify class, final classification as “Normal”, “Atrial Fibrillation”, “Other” using an ensemble of 1D CNN classifiers and a final classifier of selection using logistic regression, random forest or support vector machine (SVM). The proposed method shows high accuracy by the metric F1, so it gives the background for further research, optimization and implementation. This way this algorithm could help to save human’s life by in-time detection of problems with cardiovascular system (CVS) at early stage. Pages of the article in the issue: 70 - 77 Language of the article: UkrainianВажливість аналізу електрокардіограм (ЕКГ) важко переоцінити. Ритм життя, стреси та інші фактори впливають на частоту захворювань та їх ранні прояви. Разом з тим, технологізація (цифровізація) життя та апаратно-програмних комплекси, такі як мобільні електронні кардіографи та носимі пристрої загалом, що бурхливо розвиваються останнім часом, відкривають нові можливості для швидкого аналізу стану людини за певними показниками, а також дозволяють проводити діагностику на новому рівні практично у реальному часі. Існує багато методів для аналізу кардіограм. В даній роботі авторами запропоновано новий підхід, що ефективно розв’язує задачу аналізу ЕКГ. Дослідження базується на наборі даних PhysioNetComputing in Cardiology Challenge 2017 та MIT-BIH Arrhythmia Database. Алгоритм складається зтаких етапів: фільтрація даних, локалізація R піків, передискретизація ЕКГ, визначення класу ЕКГ задопомогою ансамблю з 1D CNN та підсумкового класифікатора. Запропонований метод показує високу точність за метрикою F1, тому являє собою цінність дляподальших досліджень, оптимізації та впровадження

Galactic Rotation Parameters from Data on Open Star Clusters

Currently available data on the field of velocities Vr, Vl, Vb for open star clusters are used to perform a kinematic analysis of various samples that differ by heliocentric distance, age, and membership in individual structures (the Orion, Carina--Sagittarius, and Perseus arms). Based on 375 clusters located within 5 kpc of the Sun with ages up to 1 Gyr, we have determined the Galactic rotation parameters Wo =-26.0+-0.3 km/s/kpc, W'o = 4.18+-0.17 km/s/kpc^2, W''o=-0.45+-0.06 km/s/kpc^3, the system contraction parameter K = -2.4+-0.1 km/s/kpc, and the parameters of the kinematic center Ro =7.4+-0.3 kpc and lo = 0+-1 degrees. The Galactocentric distance Ro in the model used has been found to depend significantly on the sample age. Thus, for example, it is 9.5+-0.7 kpc and 5.6+-0.3 kpc for the samples of young (50 Myr) clusters, respectively. Our study of the kinematics of young open star clusters in various spiral arms has shown that the kinematic parameters are similar to the parameters obtained from the entire sample for the Carina-Sagittarius and Perseus arms and differ significantly from them for the Orion arm. The contraction effect is shown to be typical of star clusters with various ages. It is most pronounced for clusters with a mean age of 100 Myr, with the contraction velocity being Kr = -4.3+-1.0 km/s.Comment: 14 pages, 4 figures, 2 table

Shape parameters of Galactic open clusters

(abridged) In this paper we derive observed and modelled shape parameters (apparent ellipticity and orientation of the ellipse) of 650 Galactic open clusters identified in the ASCC-2.5 catalogue. We provide the observed shape parameters of Galactic open clusters, computed with the help of a multi-component analysis. For the vast majority of clusters these parameters are determined for the first time. High resolution ("star by star") N-body simulations are carried out with the specially developed $\phi$GRAPE code providing models of clusters of different initial masses, Galactocentric distances and rotation velocities. The comparison of models and observations of about 150 clusters reveals ellipticities of observed clusters which are too low (0.2 vs. 0.3), and offers the basis to find the main reason for this discrepancy. The models predict that after $\approx 50$ Myr clusters reach an oblate shape with an axes ratio of $1.65:1.35:1$, and with the major axis tilted by an angle of $q_{XY} \approx 30^\circ$ with respect to the Galactocentric radius due to differential rotation of the Galaxy. Unbiased estimates of cluster shape parameters require reliable membership determination in large cluster areas up to 2-3 tidal radii where the density of cluster stars is considerably lower than the background. Although dynamically bound stars outside the tidal radius contribute insignificantly to the cluster mass, their distribution is essential for a correct determination of cluster shape parameters. In contrast, a restricted mass range of cluster stars does not play such a dramatic role, though deep surveys allow to identify more cluster members and, therefore, to increase the accuracy of the observed shape parameters.Comment: 13 pages, 12 figures, accepted for publication in Astronomy and Astrophysic

Long-range behavior of the optical potential for the elastic scattering of charged composite particles

The asymptotic behavior of the optical potential, describing elastic scattering of a charged particle $\alpha$ off a bound state of two charged, or one charged and one neutral, particles at small momentum transfer $\Delta_{\alpha}$ or equivalently at large intercluster distance $\rho_{\alpha}$, is investigated within the framework of the exact three-body theory. For the three-charged-particle Green function that occurs in the exact expression for the optical potential, a recently derived expression, which is appropriate for the asymptotic region under consideration, is used. We find that for arbitrary values of the energy parameter the non-static part of the optical potential behaves for $\Delta_{\alpha} \rightarrow 0$ as $C_{1}\Delta_{\alpha} + o\,(\Delta_{\alpha})$. From this we derive for the Fourier transform of its on-shell restriction for $\rho_{\alpha} \rightarrow \infty$ the behavior $-a/2\rho_{\alpha}^4 + o\,(1/\rho_{\alpha}^4)$, i.e., dipole or quadrupole terms do not occur in the coordinate-space asymptotics. This result corroborates the standard one, which is obtained by perturbative methods. The general, energy-dependent expression for the dynamic polarisability $C_{1}$ is derived; on the energy shell it reduces to the conventional polarisability $a$ which is independent of the energy. We emphasize that the present derivation is {\em non-perturbative}, i.e., it does not make use of adiabatic or similar approximations, and is valid for energies {\em below as well as above the three-body dissociation threshold}.Comment: 35 pages, no figures, revte

Синтез, реакційна здатність та антимікробна активність заміщених тієно[2,3-d]піримідин-4(3Н)-тіо(селено)нів

A new series of R1,R2-thieno[2,3-d]pyrimidine-4(3H)-one, thione and selenone derivatives have been synthesized; the reaction of alkylation of the compounds obtained has been studied. Their structures have been confirmed by the NMR 1H and mass spectra, and elemental analysis. The antibacterial and antifungal activities in vitro against three bacterial and two fungal pathogens have been revealed using the stiff plate agar diffusion method and the serial dilution method. The minimal bactericidal, fungicidal and bacteriostatic concentrations have been obtained. The pharmacological screening has shown that some of the compounds obtained possess a good antimicrobial activity. The culture of S.aureus. appeared to be the most sensitive to compound 10a. The best fungistatic indicators against A.niger have been found for compounds 4a and 9a.Синтезирован ряд новых производных R1,R2-тиено[2,3-d]пиримидин-4(3Н)-онов, тионов и селенонов, изучена реакция алкилирования полученных соединений. Структуры полученных соединений установлены с помощью данных ЯМР 1Н и масс-спектров, а также данных элементного анализа. Антибактериальная и фунгистатическая активность in vitro против трёх видов бактерий и двух видов грибов была обнаружена с помощью метода диффузии вещества в агар и метода серийного разведения. Определены минимальные концентрации бактериальной, фунгицидной и бактериостатической активности. Фармакологическое исследование подтвердило, что некоторые из полученных продуктов проявляют хорошую антимикробную активность. Культура бактерии S.aureus наиболее чувствительна к соединению 10а. Наилучшие фунгистатические показатели против цвелевого гриба A.niger определены для соедине-ний 4а и 9а.Синтезовано ряд нових похідних R1,R2-тієно[2,3-d]піримідин-4(3Н)-онів, тіонів і селенонів та вивчено реакцію алкілування отриманих продуктів. Структури отриманих продуктів встановлені за допомогою даних ЯМР 1Н та мас-спектрів і даних елементного аналізу. Антибактеріальну і фунгістатичну активність in vitro проти 3 культур бактерій і двох видів грибів було встановлено за допомогою методу дифузії речовини в агар і методу серійних розведень. Були визначені мінімальні концентрації бактеріальної, фунгістатичної і бактеріостатичної активності. Фармакологічне дослідження підтвердило, що деякі з отриманих продуктів проявляють добру антимікробну активність. Культура бактерії S.aureus. найбільш чутлива до сполуки 10а. Найкращі фунгістатичні показники проти цвільового гриба A.niger виявлені для сполук 4а і 9а