Contribution of Binary Stars to the Velocity Dispersion inside OB Associations with Gaia DR2 Data

Astronomy Reports - We estimated the contribution of binary systems to the velocity dispersion inside OB-associations derived from Gaia DR2 proper motions. The maximum contribution to the velocity...     

Kinematic Properties of Young Intermediate- and Low-Mass Stars from the Gaia DR2 Catalogue

Astronomy Reports - We have studied the kinematic properties of young pre-main-sequence stars. We have selected these stars based on data from the Gaia DR2 catalogue by invoking a number of...     

Chemical Composition of Globular Clusters of Milky Way Subsystems from Gaia DR2 Data

Results of a study of the kinematic and chemical properties of globular clusters of the Milky Way based on data from the Gaia DR2 catalog and meaurements with the Hubble Space Telescope are presented. A new method for dividing globular clusters into Galatic subsystems based on the elements of their Galactic orbits is proposed. Samples of globular clusters belonging to the bar/bulge, thick disk, and halo of the Milky Way are obtained. The mean metallicities of the globular clusters in various subsystems are calculated. The mean metallicities of globular clusters of the thick disk and halo display statistically significant differences. At the same time, no statistically significant differences are present between the mean metallicities of halo globular clusters moving in the direction of rotation of the Galactic disk and those moving in the retrograde direction. This argues against the suggestion that retrograde and prograde globular clusters have different origins.

     

Physical and Chemical Properties of Galactic Global Clusters with Various Origins Identified from the Gaia DR2 Data

Astronomy Reports - The differences in the relationships between the physical parameters and the chemical-element abundances in accreted globular star clusters and those formed inside the Galaxy...     

Galaxy Rotation Parameters from OB2 Stars with Proper Motions and Parallaxes from the Gaia EDR3 Catalog

Astronomy Reports - We have analyzed the kinematics of OB2 stars with proper motions and parallaxes selected by Xu et al. from the Gaia EDR3 catalog. The relative parallax errors for all the stars...     

Improving the Orbits of Four Visual Binaries Using Gaia DR2 Data and Observations with the 26-inch Refractor of Pulkovo Observatory

Astronomy Reports - We use a modified method of the apparent motion parameters (AMP), in which the initial data from the Gaia DR2 catalog are not only high-precision coordinates, parallaxes, and...     

Close Binary Stars. VIII: Close Binary Star Systems in the Late Stages of Evolution

Astronomy Reports - The paper analyzes observations of close binary systems (CBSs), their radial velocity curves, and light curves. Various methods are described for fitting the light curve of...     

Searching for Observational Evidence for Binary Star Systems in Gamma-ray Bursts

Astronomy Reports - We search for observational evidence that is in agreement with the model of a binary star system in gamma-ray bursts (GRBs), as presented in [1–3]. The model predicts...     

Comparison of the Orbital Properties of the Milky Way Globular Clusters from the Data of the Gaia DR2 and EDR3 Catalogs

Astronomy Reports - We provide new values of the orbital parameters of 152 globular clusters, which are calculated using the new mean proper motions obtained from the Gaia EDR3 catalog data. The...     

Parameters of X-Ray Binary Sco X-1 in the Model of Partial Filling of Roche Lobe by Optical Star

Astronomy Reports - We have simulated optical orbital light curves of the Sco X-1 system obtained by the Kepler space observatory during K2 mission. Simulation was carried out under assumption that...     

On the Status of the Star Schulte 12 in the Association Cyg OB2

Astronomy Reports - High-resolution spectra of the LBV candidate Schulte 12 in the Cyg OB2 association were obtained at the 6-m BTA telescope with the NES echelle spectrograph on the arbitrary...     

Population geography with GIS in Japan

Japanese geography studies are now being greatly affected by the rapid development of geographical information systems (GIS). Unfortunately, there has been little response from Japanese population geographers to this movement. Is GIS a welcome or an unwelcome guest? After discussing the significance of employing GIS, this article introduces some recent papers that used GIS in the field of population geography on such issues as mortality mapping, migration analysis, and household studies. Then, the two promising population-related topics of married one-person households and fertility are discussed. The ability of GIS to greatly facilitate analysis, which previously needed much time and energy, can be an encouraging stimulus of innovation in studies of current population geography. Therefore, GIS is clearly a welcome guest, although it is too wishful to think that its use would lead directly to a revitalization of contemporary population geography studies.     

Turbulence in the Accretion Disks in Semi-Detached Binary Systems with Various Component-Mass Ratios

Results of three-dimensional gas-dynamical numerical simulations of the structure of matter flows in semi-detached binary systems with various component-mass ratios are considered. The main elements of the flows in the models studied are described. The characteristics of density waves inside the accretion disk for various component-mass ratios are considered. The influence of the precessional density wave on the development of instability in the accretion disks and the characteristics of developing turbulence are analyzed. Values of the Shakura–Syunyaev coefficient α for the simulated systems are calculated.     

Evolution of OH and H2O Maser Emission in the Active Star Formation Region NGC 2071

Astronomy Reports - We present the observation results of the star forming region NGC 2071 in the 1.35-cm H2O line and 18-cm OH lines obtained with the 22-m radio telescope in Pushchino (Russia)...     

Eclipsing Binary Systems XZ Per and BO Vul with Complex Variations in Orbital Periods

Astronomy Reports - The variations in the orbital periods of the eclipsing binary systems XZ Per and BO Vul have been studied. It has been shown that the variations in the orbital period of the...     

含水层的一种普遍规律:渗透系数随深度衰减

国内外多个含水层的研究都发现渗透系数具有随深度衰减的规律。给出了多孔介质和裂隙介质中渗透系数随深度衰减的一般模型及简化模型,并用该简化模型分析了多个含水层的渗透系数随深度衰减的规律。研究发现,随着渗透系数测试深度的增大,衰减系数明显变小;渗透系数测试深度相近的含水层,岩性对衰减系数有一定程度影响。渗透系数随深度衰减的规律应该在地下水科学的相关研究中引起重视。     

Contribution of a Dense Population of the Brittle Star <Emphasis Type="Italic">Acrocnida brachiata</Emphasis> (Montagu) to the Biogeochemical Fluxes of CO<Subscript>2</Subscript> in a Temperate Coastal Ecosystem

The production of organic matter and calcium carbonate by a dense population of the brittle star Acrocnida brachiata (Echinodermata) was calculated using demographic structure, population density, and relations between the size (disk diameter) and the ash-free dry weight (AFDW) or the calcimass. During a 2-year survey in the Bay of Seine (Eastern English Channel, France), organic production varied from 29 to 50 g_AFDW m⁻² year⁻¹ and CaCO₃ production from 69 to 104 g_CaCO3 m⁻² year⁻¹. Respiration was estimated between 1.7 and 2.0 mol_CO2 m⁻² year⁻¹. Using the molar ratio (ψ) of CO₂ released: CaCO₃ precipitated, this biogenic precipitation of calcium carbonate would result in an additional release between 0.5 and 0.7 mol_CO2 m⁻² year⁻¹ that represented 23% and 26% of total CO₂ fluxes (sum of calcification and respiration). The results of the present study suggest that calcification in temperate shallow environments should be considered as a significant source of CO₂ to seawater and thus a potential source of CO₂ to the atmosphere, emphasizing the important role of the biomineralization (estimated here) and dissolution (endoskeletons of dead individuals) in the carbon budget of temperate coastal ecosystems.     

Population changes in a growth center region with reference to the Israeli Negev

The aim of this paper is to present a scheme of relative population changes in a geographic-termed growth center region, with reference to a real problem of development as implemented in the Israeli Negev arid zone. The growth process described in the scheme leads to dynamic steady-states which indicate stable structure and stable relationships between the components of the regional system — the growth center and its urban and rural hinterlands. It was found that the relative population growth process in the Negev during the last thirty years is similar to the process determined by the scheme. Furthermore, geo-political changes in the area due to the peace treaty between Egypt and Israel may alter this process and open a new period of regional growth. An additional thrust of this paper is methodological: to introduce and apply the hexagonal diagram to describe and classify processes of relative population growth.     

强渗透性地层旋挖钻施工混凝土灌注桩质量通病分析

对强渗透性地层旋挖钻进成孔混凝土灌注桩质量通病进行了分析,总结此类地层必须重视泥浆护壁质量对混凝土灌注桩施工质量的重大影响,必须重视钻斗的活塞抽吸对孔壁的破坏性,建议其验收标准中增加泥浆护壁质量验收,重视清孔后的孔径验收,不可完全沿用与旋挖钻孔泥浆护壁效果有着天壤区别的回转钻、潜水钻成孔混凝土灌注桩的质量验收标准。     

Cyclic Orbital-period Variations in Eclipsing Binary Systems with Rapid Period Decreases: TU Her,TY Peg,and Y Psc

Cyclic variations of the orbital period superposed on a secular period decrease have been found for the Algol-type eclipsing binaries TU Her, TY Peg, and Y Psc. A superposition of two kinds of cyclic variations is observed for TU Her and Y Psc: with periods of 69.4 years and 30.0 years for TU Her, and 34.4 and 23.2 years for Y Psc. One type of oscillation, with a period of 74.3 years, was detected for TY Peg. The cyclic orbital-period variations of TY Peg and Y Psc can be successfully fitted using the light-time effect, and also with magnetic oscillations. In the case of TU Her, the light-time effect is able to explain only one of the cyclic variations, the one with the shorter period.