323 research outputs found
Modulation of Circumstellar Extinction in a Young Binary System with a Low-Mass Companion in a Noncoplanar Orbit
The cyclic activity model of a young star with the low-mass secondary
component (q = M2/M1 <= 0.1) accreting a matter from circumbinary disk is
considered. It is assumed that the orbit is circular and the disk and orbital
planes are non-coplanar. Sets of hydrodynamics models of such a system have
been calculated by the SPH method and then the variations of the circumstellar
extinction and phase light curves were determined. The calculations showed that
depending on the model parameters and orientation of the system in regards to
an observer the different in shape and amplitude light curves can be observed.
An important property of the considered models is also the dependence of the
mass accretion rate onto the components on the phase of the orbital period. The
results of the calculation can be used for analysis of the cyclic activity of
UX Ori stars and young stars with the long-lasting eclipses.Comment: 14 pages, 7 figure
Internet diffusion and interregional digital divide in Russia: trends, factors, and the influence of the pandemic
The demand for digital technologies has been growing due to a shift in the technological and economic paradigm. The need for online services has increased since the beginning of the COVID pandemic. There are significant disparities between Russian regions in the digital technology accessibility and the development of computer skills. In 2020, the Internet diffused rapidly in most regions, although previously, there had been a slowdown. As markets got saturated with digital services, the digital divide between Russian regions narrowed. Overall, the Internet use patterns are consistent with those of the spatial diffusion of innovations. Amongst the leaders, there are regions home to the largest agglomerations and northern territories of Russia, whereas those having a high proportion of rural population lag behind. Coastal and border regions (St. Petersburg, the Kaliningrad region, Karelia, Primorsky Krai, etc.) have better access to the Internet due to their proximity to the centres of technological innovations as well as the high intensity of external relations. Leading regions have an impact on their neighbours through spatial diffusion. Econometrically, access to the Internet depends on income, the average age and level of education, and its use depends on the business climate and Internet accessibility factors. Regional markets are gradually getting more saturated with digital services and technologies. The difference between regions in terms of access to the Internet is twofold, whereas, in terms of digital technology use, the gap is manifold. In many regions, the share of online commerce, which became the driver of economic development during the lockdown, is minimal. Based on the results of the study, several recommendations have been formulated
ΠΠ½ΡΠΎΠΊΠΎΠΌΠΌΡΠ½ΠΈΠΊΠ°ΡΠΈΠΎΠ½Π½ΡΠ΅ ΡΠ΅Ρ Π½ΠΎΠ»ΠΎΠ³ΠΈΠΈ Π² ΠΌΠ΅Π΄ΠΈΡΠΈΠ½Π΅
Π‘ΡΠ°ΡΡΡ ΠΏΠΎΡΠ²ΡΡΠ΅Π½Π° ΡΠ°ΡΡΠΌΠΎΡΡΠ΅Π½ΠΈΡ ΡΠ°ΠΊΠΎΠΉ ΠΎΠ±Π»Π°ΡΡΠΈ ΠΌΠ΅Π΄ΠΈΡΠΈΠ½Ρ, ΠΊΠ°ΠΊ ΡΠ΅Π»Π΅ΠΌΠ΅Π΄ΠΈΡΠΈΠ½Π°. Π ΡΡΠ°ΡΡΠ΅ ΠΏΡΠ΅Π΄ΡΡΠ°Π²Π»Π΅Π½Ρ ΡΠΏΠΎΡΠΎΠ±Ρ ΠΈΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°Π½ΠΈΡ ΠΈΠ½ΡΠΎΠΊΠΎΠΌΠΌΡΠ½ΠΈΠΊΠ°ΡΠΈΠΎΠ½Π½ΡΡ
ΡΠ΅Ρ
Π½ΠΎΠ»ΠΎΠ³ΠΈΠΉ Π² ΠΌΠ΅Π΄ΠΈΡΠΈΠ½Π΅.The article is devoted to the consideration a field of medicine - telemedicine. The article presents the ways of using infocommunication technologies in medicine
Bimodal Brightness Oscillations in Models of Young Binary Systems
We consider a model for the cyclic activity of young binary stars that
accrete matter from the remnants of a protostellar cloud. If the orbit of such
a binary system is inclined at a small angle to the line of sight, then the
streams of matter and the density waves excited in the circumbinary disk can
screen the primary component of the binary from the observer. To study these
phenomena by the SPH (smoothed particle hydrodynamics) method, we have computed
grids of hydrodynamic models for binary systems based on which we have
constructed the light curves as a function of the orbital phase.The main
emphasis is on investigating the properties of the brightness oscillations.
Therefore, the model parameters were varied within the following ranges: the
component mass ratio q = M2 : M1 = 0.2 - 0.5 and the eccentricity e = 0 - 0.7.
The parameter that defined the binary viscosity was also varied. We adopted
optical grain characteristics typical of circumstellar dust. Our computations
have shown that bimodal oscillations are excited in binaries with eccentric
orbits, provided that the binary components do not differ too much in mass. In
this case, the ratios of the periods and amplitudes of the bimodal oscillations
and their shape depend strongly on the inclination of the binary plane and its
orientation relative to the observer. Our analysis shows that the computed
light curves can be used in interpreting the cyclic activity of UX Ori stars.Comment: 14 pages, 5 figures, 1 tabl
Erratum: On the stability and interannual variability in the hydrochemical structure of the redox layer of the black sea (Oceanology (2005) vol. 45 (S61))
Modeling the employment rate in Russia: A spatial-econometric approach
The purpose of this study is to identify factors that affect the level of employment in Russian regions. However, Russia is not a homogeneous country, and this effect may not be the same for all regions. That is why we split the regions of Russia into three groups, depending on the state of the labor market in this and neighboring regions. The HH (high-high) group comprises regions with a favorable situation in their labor markets, and which are also surrounded mostly by prosperous regions. Two groups of regions with a less favorable situation are located respectively in the south of Russia (LL1, low-low group 1) and southern Siberia and Zabaikalye (LL2, low-low group 2). We considered the twelve-year period from 2005 to 2016. As explanatory variables, we used variables for the attractiveness of the region, demographic characteristics of the region, and the degree of diversity of employees by economic activities. We tested hypotheses about differences in 1) the spatial effects and 2) the impact of the various explanatory variables for these groups of variables. To test our main hypotheses, we used spatial regression dynamic models estimated with the help of the generalized method of moments. Both main hypotheses received empirical confirmation. Spatial effects were different. The regions of the LL2 group are not affected by the situation in other local markets; regions of LL1 and HH groups are affected by the rest of Russiaβs regions, and the extent of this influence decreases with the increase in geographical distance between regions. Moreover, the regions of the LL1 group compete with neighboring regions: if the situation in one of them improves, then it draws on the resources of the others. Regarding the impact of the explanatory variables, the βgroup effectβ was revealed for the variables: share of urban population, net migration rate, shares of people below and above working age, share of people with higher education. Our results can favor the better design of national and regional policies to improve labor market performance in Russia based on the heterogeneity of the Russian regions. Β© Demidova O. A., Daddi P., Medvedeva E. V., Signorelli M. Text. 201
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