A principal possibility for computer investigation of evolution of dynamical systems with independent on time accuracy

Extensive N-body simulations are among the key means for the study of numerous astrophysical and cosmological phenomena, so various schemes are developed for possibly higher accuracy computations. We demonstrate the principal possibility for revealing the evolution of a perturbed Hamiltonian system with an accuracy independent on time. The method is based on the Laplace transform and the derivation and analytical solution of an evolution equation in the phase space for the resolvent and using computer algebra.Comment: Eur Phys Journ C (in press), to match the version to appear, 7 pages, 3 fig

A new exactly integrable hypergeometric potential for the Schr\"odinger equation

We introduce a new exactly integrable potential for the Schr\"odinger equation for which the solution of the problem may be expressed in terms of the Gauss hypergeometric functions. This is a potential step with variable height and steepness. We present the general solution of the problem, discuss the transmission of a quantum particle above the barrier, and derive explicit expressions for the reflection and transmission coefficients

Anti-solar differential rotation on the active sub-giant HU Virginis

Measuring surface differential rotation (DR) on different types of stars is important when characterizing the underlying stellar dynamo. It has been suggested that anti-solar DR laws can occur when strong meridional flows exist. We aim to investigate the differential surface rotation on the primary star of the RS CVn binary HU Vir by tracking its starspot distribution as a function of time. We also aim to recompute and update the values for several system parameters of the triple system HU Vir (close and wide orbits). Time-series high-resolution spectroscopy for four continuous months was obtained with the 1.2-m robotic STELLA telescope. Nine consecutive Doppler images were reconstructed from these data, using our line-profile inversion code iMap. An image cross-correlation method was applied to derive the surface differential-rotation law for HU Vir. New orbital elements for the close and the wide orbits were computed using our new STELLA radial velocities (RVs) combined with the RV data available in the literature. Photometric observations were performed with the Amadeus Automatic Photoelectric Telescope (APT), providing contemporaneous Johnson-Cousins $V$ and $I$ data for approximately 20 years. This data was used to determine the stellar rotation period and the active longitudes. We confirm anti-solar DR with a surface shear parameter $\alpha$ of -0.029 $\pm$ 0.005 and -0.026 $\pm$ 0.009, using single-term and double-term differential rotation laws, respectively. The best fit is achieved assuming a solar-like double-term law with a lap time of $\approx$ 400 d. Our orbital solutions result in a period of 10.387678 $\pm$ 0.000003 days for the close orbit and 2726 $\pm$ 7 d ($\approx$ 7.5 yr) for the wide orbit. A Lomb-Scarge (L-S) periodogram of the pre-whitened $V$-band data reveals a strong single peak providing a rotation period of 10.391 $\pm$ 0.008 d.Comment: Accepted for publication in A&

Micropropagation of grapevine (Vitis vinifera L.) seedless cultivar 'Parvana' through lateral bud development

Factors affecting successful establishment in vitro, rapid proliferation, rooting and acclimatization of grapevine seedless cultivation 'Parvana' were studied. A treatment combination of 2.0 % calcium hypochlorite for 7 minutes plus 70 % ethanol for 3 minutes was found to be effective with 75.0 % of aseptic culture establishment in vitro. The highest number of new microshoots (4.5) was obtained in a culture medium (Gambourg's B5 modification) supplemented with 0.6 mg∙L-1 BAP + 0.2 mg∙L-1 KIN + 0.5 mg∙L-1 GA3. Presence of GA3 in combination with BAP and KIN promoted elongation of shoots. A concentration of 0.4 mg/l IAA in half strength of MS (Murashige and Skoog) proved to be the best for rooting (84.4 % root induction, 4.66 roots with 7.9 cm length). In vitro rooted plantlets were successfully acclimatized, with 82.2 % survival rate in plastic pots containing garden soil, sand and peat moss(1:1:1). In this study an efficient micro propagation technique of grapevine seedless cultivar 'Parvana' was successfully achieved through lateral bud culture. Such a technique would be useful for large scale plant production and in vitro conservation

Holomorphic Bloch spaces on the unit ball in CnC^n

summary:This work is an introduction to anisotropic spaces of holomorphic functions, which have $\omega$-weight and are generalizations of Bloch spaces on a unit ball. We describe the holomorphic Bloch space in terms of the corresponding $L_\omega ^\infty$ space. We establish a description of $(A^p(\omega ))^*$ via the Bloch classes for all $0<p\leq 1$

Армения на пути к «новой экономике»: оборонная промышленность

In fact, a new arms race could start in the world as a side effect of the so-called “4th Industrial Revolution” – the main innovative trend of which is the widespread use of technologies such as artificial intelligence, machine learning, quantum computing, additive manufacturing, robotics, Internet of things, cloud technologies etc., and the countries involved in military conflicts cannot neglect this circumstance. As a small country, Armenia needs an economy-army coalesced “intelligent” system that will respond adequately to any, even the slightest threat to the country's security. This approach requires the development of indigenous defense industry. It is obvious that the development of Armenian defense industry is in the inevitable point of intersection of the new wave of economic transformations and the breakthrough of the “4th Industrial Revolution”, as the initiator of positive changes in the economy, from which positive externalities must be spread throughout the economy by a chain reaction. The article discusses the issues of defense industry development in Armenia in accordance with new challenges of Industry 4.0.Побочным эффектом так называемой «4-й промышленной революции», основной инновационной тенденцией которой является широкое применение таких технологий, как искусственный интеллект, машинное обучение, квантовые вычисления, аддитивное производство, робототехника, интернет вещей, облачные технологии и т.д., может стать по сути новая гонка вооружений, и страны, вовлеченные в военные конфликты, не могут пренебрегать этим обстоятельством. Как небольшая страна, вовлечённая в локальный конфликт, Армении нужна такая синергетическая (с взаимоусиляющими компонентами) «интеллектуальная» система «армия-экономика», которая сможет адекватно реагировать на любую угрозу безопасности страны. Очевидно, что в неизбежной точке пересечения новой волны экономических преобразований в Армении и нового прорыва «4-ой промышленной революции» находится оборонная промышленность, в качестве инициатора позитивных изменений в экономике, откуда положительные экстерналии цепной реакцией должны распространяться по всей экономике. В статье рассматриваются вопросы развития оборонной промышленности Армении в контексте новых вызовов Индустрии 4.0.

The isotropic correlation function of plane figures: the triangle case

The knowledge of the isotropic correlation function of a plane figure is useful to determine the correlation function of the cylinders having the plane figure as right-section and a given height as well as to analyze the out of plane intensity collected in grazing incidence small-angle scattering from a film formed by a particulate collection of these cylinders. The correlation function of plane polygons can always be determined in closed algebraic form. Here we report its analytic expression for the case of a triangle. The expressions take four different forms that depend on the relative order among the sides and the heights of the triangle.Comment: 11 pages, 2 figure