Applying a criterion previously derived by the author, the stability of stellar systems with an isotropic distribution velocity distribution and Emden's polytropic density law is demonstrated for the exponent n = 3/2.

We live in the golden age of distributed computing. Public cloud platforms now offer virtually unlimited compute and storage resources on demand. At the same time, the Software-as-a-Service (SaaS) model brings enterprise-class systems to users who previously could not afford such systems due to their cost and complexity. Alas, traditional data warehousing systems are struggling to fit into this new environment. For one thing, they have been designed for fixed resources and are thus unable to leverage the cloud's elasticity. For another thing, their dependence on complex ETL pipelines and physical tuning is at odds with the flexibility and freshness requirements of the cloud's new types of semi-structured data and rapidly evolving workloads. We decided a fundamental redesign was in order. Our mission was to build an enterprise-ready data warehousing solution for the cloud. The result is the Snowflake Elastic Data Warehouse, or "Snowflake" for short. Snowflake is a multi-tenant, transactional, secure, highly scalable and elastic system with full SQL support and built-in extensions for semi-structured and schema-less data. The system is offered as a pay-as-you-go service in the Amazon cloud. Users upload their data to the cloud and can immediately manage and query it using familiar tools and interfaces. Implementation began in late 2012 and Snowflake has been generally available since June 2015. Today, Snowflake is used in production by a growing number of small and large organizations alike. The system runs several million queries per day over multiple petabytes of data. In this paper, we describe the design of Snowflake and its novel multi-cluster, shared-data architecture. The paper highlights some of the key features of Snowflake: extreme elasticity and availability, semi-structured and schema-less data, time travel, and end-to-end security. It concludes with lessons learned and an outlook on ongoing work.

The initial stages of the evolution of a spherical star system can be pictured in the following way. The stars have their beginning in a comparatively small region; the mechanism of the origin of initial velocities is not known exactly. From the point of view of the contemporary state of stellar astronomy, it is an acceptable view that the initial velocities have their origin in the attraction of each individual star towards the center of gravity of the system. The second possible assumption is to attribute the origin of initial velocities to forces of an explosive character. But in either case, initially, all orbits have to be almost exactly radial.

Главная астрономическая обсерватория РАН, Пулково К проблеме устойчивости звездных систем применяется метод А.М.Ляпунова. Для частного случая, когда фазовая плотность зависит только от интеграла энергии, найден критерий устойчивости, хотя и довольно сложный. ЗАУВАЖЕННЯ ДО ПРОБЛЕМИ СТIЙКОСТI В ЗОРЯНIЙ ДИНАМIЦI, Антонов В.А. До проблеми стiйкостi зоряних систем застосовується метод А.М.Ляпунова. Для часткового випадку, коли фазова густина залежить тiльки вiд iнтегралу енергiї, знайдено критерiй стiйкостi, хоча i доволi складний. REMARKS ON THE PROBLEM OF STABILITY IN STELLAR DYNAMICS, by Antonov V.A. Lyapunov's method is applied to the problem of stability of stellar systems. The stability criterium is obtained for the particular case, when the phase density depends only on the energy integral.

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An estimate is made of the maximum range over which the motion of a particle about the Sun and in the galactic field is stable in Hill's sense. An equation fitting the Hill surface is found, with allowance made for the fact that the galactic potential differs from that of a point mass. The volume enclosed by the surface is 3.35 cubic parsecs, the greatest distance from the Sun being 1.42 parsecs, this being along the line to the centre of the Galaxy.

During the epidemic season of 2012 453 cases of West Nile fever (WNF) were registered in the territory of the 21 constituent entities of the Russian Federation. Epidemic process is spreading itself towards the northern regions of Russia. The presence of markers of West Nile fever virus in carriers and vectors of the disease as well as acquired immunity among the population against the West Nile virus (WNV) have been identified in the territory of 53 constituent entities of the Russian Federation. The epidemic process is characterized by a number of peculiarities concerning both its epidemiological and clinical aspects. With the intensification of diagnostic works among the patients with clinical symptomatology similar to WNF, first and foremost in the territories where WNV markers have been detected, prognosticated is the registration of WNF incidence among the population extending over a large area of the Russian Federation.