慕课在远程网络教师教育领域的应用探析

随着近年来慕课浪潮的兴起,我国现行远程网络教师教育所存在的授课思想落后、授课形式枯燥单一以及评价方式重量轻质等问题逐渐凸显。现阶段我国慕课平台虽然提供了许多国外高校开设的有关教师教育的课程,但对于我国慕课学习者而言,还存在着一定的学习障碍。未来我国远程网络教师教育可以吸取慕课先进经验,在课程平台、教师角色以及教学流程等方面进行有效变革,从而促进我国远程网络教师教育健康发展。     

Spectropolarimetric observations of active galactic nuclei with the 6-m BTA telescope

We present the results of our spectropolarimetric observations for a number of active galactic nuclei (AGNs) carried out at the 6-m telescope with the SCORPIO focal reducer. The derived wavelength dependences of the polarization have been analyzed by taking into account the Faraday rotation of the polarization plane on the photon mean free path in a magnetized accretion disk. As a result, based on traditional accretion disk models, we have determined the magnetic field strength and distribution and a number of physical parameters of the accreting plasma in the region where the optical radiation is generated.     

Spectrophotometry of HD 182255

We investigate the HD 182255, a star earlier suspected to be helium-weak. We show it to be a SiHe-w-type CP object. Our study revealed four regions with anomalous elemental abundances on the stellar surface near the equator of rotation. Its magnetic field could not be measured, apparently due to the unfavorable orientation of the star. The star is seen almost (rotation) pole on, the inclination of its rotation axis is i = 12°. The magnitude of HD 182255 varies as a result of its rotation owing to the nonuniform distribution of chemical elements on its surface, which leads to the variable blanketing effect. The helium and silicon abundances increase with depth, i.e., the stratification typical of CP stars is observed. The star undergoes nonradial pulsations and nonstationary variations of the structure of its upper atmosphere.     

Mechanism for cyclical activity of the Herbig Ae star BF Ori

The photometric activity of the star BF Ori, which belongs to the family of UX Ori-type stars, is studied. New data obtained with the ASAS robotic telescope confirm the existence of a cyclical component in the light curve for this star with a duration of roughly 11-12 years. The form of the photometric cycle resembles the theoretical light curves for a young binary system with a low-mass secondary component, and which is accreting matter from a surrounding common disk. Alternative mechanisms for the cyclical variability of UX Ori stars are also discussed.     

Some properties of the He-w star HD 35502

This is a preliminary study of the star HD 35502. Its magnetic field has been measured in different phases of its period. Preliminary values of the magnetic field parameters have been obtained based on a central quadrupole model. The effective magnetic field Be varies over 0-5000 G, the average surface magnetic field ranges over 6300-6700 G, the field at the poles is Bp=7000 G, and the angle between the quadrupole axis and the axis of rotation is β = 80o. As a first approximation, the surface helium is concentrated around the (negative) pole and for τ > 1 its abundance is reduced by approximately 2-4 dex, which confirms the hypothesis of helium diffusion under the action of gravitation and wind in a stable atmosphere. The chemical elements Si and Cr are concentrated in four spots on the magnetic equator between the magnetic poles, or in a ring coincident with the magnetic equator; precisely which is not clear at present.     

Contributions of the Pulkovo and Kharkiv Scientific Schools to the search for exoplanets and low-mass dark satellites of stars

This article is devoted to the Pulkovo astronomer, Prof. Aleksandr Nikolaevich Deich (Deutsch) (1899-1986), on the 110-th anniversary of his birth. Deich is known as the founder of the Pulkovo program for observing stars with invisible companions, as well as for his research on the star 61 Cyg, which was suspected, in his time, of having invisible companions with the masses of planets. Astrometric observations on the long focus astrograph and searches for exoplanets of nearby stars are reviewed. Modern methods of searching for exoplanets are summarized briefly. Instrument designs proposed by astronomers at Kharkiv (Scientific Research Institute of Astronomy at Kharkiv National University, NIIA KhNU) and Kazan (Institute of Astronomy, Kazan State University, AO KGU) for use in the search for low-mass dark components of stars are discussed. Examples are given of confirmations of invisible companions of stars which were first discovered by observation. A number of theoretical results on this topic from Kharkiv National University (Scientific Research Institute of Astronomy at Kharkiv and the Dept. of Astronomy) are noted.     

Automated search for star clusters in large multiband surveys: II. Discovery and investigation of open clusters in the galactic plane

Automated search for star clusters in J, H, K _s data from 2MASS catalog has been performed using the method developed by Koposov et al. (2008). We have found and verified 153 new clusters in the interval of the galactic latitude −24° < b < 24°. Color excesses E(B − V), distance moduli and ages were determined for 130 new and 14 yet-unstudied known clusters. In this paper, we publish a catalog of coordinates, diameters, and main parameters of all the clusters under study. A special web-site available at has been developed to facilitate dissemination and scientific usage of the results.     

Contribution of close double white dwarfs to the Galactic gravitational wave foreground

This paper provides new detailed specifics and characteristics of the close double white dwarfs (CDWDs) LISA foreground noise floor using the newest information on the astrophysics with binary population algorithms, which were judged to satisfy the observations. We use the binary population synthesis approach of CDWDs in combination with the latest findings of synthesis models from Han (Mon. Not. R. Astron. Soc. 296:1019, 1998), here, specifically formation by the three evolutionary channels of (a) stable Roche lobe overflow plus common envelope (RLOF?+?CE), (b) CE plus CE, (c) exposed core plus CE. We collect resulting CDWDs in the frequency range of 10^?8 Hz to 10^?2 Hz and compare strength and number statistics per resolvable frequency bin to derive the properties of the noise floor and the nature of possible outliers that may become individually resolvable. We find resolvable outliers to be solely produced by CE?+?CE evolution; the other two channels contribute only to the unresolvable foreground noise. Within the CE?+?CE evolution a detailed look into the chemical buildup of the stars reveals dominantly double helium (He?+?He) WDs or carbon-oxygen CO?+?He WDs.