bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fiber substrates in the nutrition of weaned piglets – a review
Authors: Flis Marianna , Sobotka Wiesław , Antoszkiewicz Zofia 
Published: February 2017

Abstract
The present review summarizes the results of 37 experiments in which different types and levels (from 0.5 to 29.7%) of fibrous supplements were used in the formulation of diets for weaned piglets. Diets were supplemented with different sources of insoluble dietary fiber (iDF), soluble dietary fiber (sDF), or mixed DF sources. Most of the applied DF sources decreased the ileal and fecal organic matter digestibility, and they often lowered crude protein digestibility. A moderate addition (1.5-8%) of iDF sources increased average daily feed intake (ADFI) and, frequently, average daily gains (ADG). Sources of sDF as well as high inclusion levels of fiber-rich feeds tended to decrease ADFI and ADG. Improved fecal consistency, decreased diarrhea incidence and antibiotic interventions were confirmed in piglets fed diets with added lignocellulose, cooked or raw oat hulls and wheat bran. The dietary inclusion of iDF rather than sDF sources improved gastrointestinal tract (GIT) development, enzyme activity and gut morphology. An increase in the counts of beneficial gut microbiota and the concentrations of short-chain fatty acids was stimulated by diets with addition iDF or sDF sources. Such diets also slowed down proteolytic fermentation which negatively affects the colonic mucosa. Some research findings indicate that iDF sources improve intestinal barrier function. The analyzed experimental data suggest that the addition of 1.5-2% of a lignocellulose preparation, 2% of oat hulls, 4-8% of coarse wheat bran to diets for weaned piglets may be recommended to promote GIT development and health, and to improve growth performance.
Radio Astronomical and Radiophysical Studies in the Near-Earth Space in the Radiophysical Research Institute
Authors: Snegirev S. D. , Bakhmetieva N. V. , Dugin N. A. , Karashtin A. N. , Uryadov V. P. 
Published: February 2017

AbstractThe paper describes possibilities of the experimental investigations of the near-Earth space by the facilities of the Radiophysical Research Institute at Nizhny Novgorod. We describe the experimental equipment, development of the research methods and some recent results.
Investigation of the Earth Ionosphere Using the Radio Emission of Pulsars
Authors: Ulyanov O. M. , Shevtsova A. I. , Mukha D. V. , Seredkina A. A. 
Published: February 2017

AbstractThe investigation of the Earth ionosphere both in a quiet and a disturbed states is still desirable. Despite recent progress in its modeling and in estimating the electron concentration along the line of sight by GPS signals, the impact of the disturbed ionosphere and magnetic field on the wave propagation still remains not sufficiently understood. This is due to lack of information on the polarization of GPS signals, and due to poorly conditioned models of the ionosphere at high altitudes and strong perturbations. In this article we consider a possibility of using the data of pulsar radio emission, along with the traditional GPS system data, for the vertical and oblique sounding of the ionosphere. This approach also allows to monitor parameters of the propagation medium, such as the dispersion measure and the rotation measure using changes of the polarization between pulses. By using a selected pulsar constellation it is possible to increase the number of directions in which parameters of the ionosphere and the magnetic field can be estimated.
Further Investigation of the Effect of Galaxy Interactions on Star Formation
Authors: Deng Xin-Fa , Zhang Fuyang 
Published: February 2017

Abstract
From the apparent magnitude-limited the Main galaxy sample of the Sloan Digital Sky Survey Data Release 7, we construct a paired galaxy sample and a control sample without close companions with the projected separations rp
< 100 h
−1 kpc and relative velocity ΔV < 350 km/s, and then perform their comparative studies. It is found that galaxy pairs have significantly lower star formation rate (SFR) and specific star formation rate (SSFR) than galaxies without close companions. We also find that this effect probably originates due to a correlation between the environment and the SFR.
A New High-Precision Correction Method of Temperature Distribution in Model Stellar Atmospheres
Authors: Sapar A. , Poolamäe R. , Sapar L. 
Published: February 2017

Abstract
The main features of the temperature correction methods, suggested and used in modeling of plane-parallel stellar atmospheres, are discussed. The main features of the new method are described. Derivation of the formulae for a version of the Unsöld-Lucy method, used by us in the SMART (Stellar Model Atmospheres and Radiative Transport) software for modeling stellar atmospheres, is presented. The method is based on a correction of the model temperature distribution based on minimizing differences of flux from its accepted constant value and on the requirement of the lack of its gradient, meaning that local source and sink terms of radiation must be equal. The final relative flux constancy obtainable by the method with the SMART code turned out to have the precision of the order of 0.5 %. Some of the rapidly converging iteration steps can be useful before starting the high-precision model correction. The corrections of both the flux value and of its gradient, like in Unsöld-Lucy method, are unavoidably needed to obtain high-precision flux constancy. A new temperature correction method to obtain high-precision flux constancy for plane-parallel LTE model stellar atmospheres is proposed and studied. The non-linear optimization is carried out by the least squares, in which the Levenberg-Marquardt correction method and thereafter additional correction by the Broyden iteration loop were applied. Small finite differences of temperature (δT/T = 10−3) are used in the computations. A single Jacobian step appears to be mostly sufficient to get flux constancy of the order 10−2 %. The dual numbers and their generalization – the dual complex numbers (the duplex numbers) – enable automatically to get the derivatives in the nilpotent part of the dual numbers. A version of the SMART software is in the stage of refactorization to dual and duplex numbers, what enables to get rid of the finite differences, as an additional source of lowering precision of the computed results.
On the Nature of V2282 Sgr
Authors: Nesci R. , Rossi C. , Frasca A. , Marilli E. , Persi P. 
Published: February 2017

Abstract
The star V2282 Sgr is positionally consistent with a strong Chandra X-ray and a Spitzer/IRAC mid-infrared source. We derived its long-term I-band light curve from the photographic archives of the Asiago and Catania Observatories, covering the years from 1965 to 1984. Also, CCD R
C photometry of 2009 was re-analyzed. Optical spectra were collected at the Loiano Observatory in 2011 and 2012. J,H,Ks
photometry, obtained from several sources in different epochs was compared and the Spitzer images were re-analyzed. V2282 Sgr was found to be irregular variable in all wavelengths. Spectroscopically, it shows strong emission features (H Balmer lines, [N II] 6584Å and [O III] 5007/4959Å) while the Na I D-doublet is very strong, indicating a circumstellar envelope. A single thermal energy distribution cannot reproduce the observed SED, while it can be explained as the sum of a G-type star plus a variable circumstellar disk, which mimics YSO of class 0/I. Most likely, V2282 Sgr is a 1–2 M
⊙ mass pre-main-sequence star with an accretion disk.
Optical Spectroscopy of a post-AGB star HD 187885
Authors: Kipper Tõnu 
Published: February 2017

Abstract
The physical parameters of the atmosphere and its chemical composition for a post-AGB star HD 187885 are determined from high resolution spectra. The effective temperature T
eff = 8000 ± 200 K and the surface gravity log g = 1.0 ± 0.3 were derived. The star was found to be metal-deficient with [Fe/H] = −0.51. The α-elements, except of Ca and Ti, and the s-process elements are overabundant. These results partly confirm and supplement the data available in the literature. The spectrum shows many circumstellar lines formed in the multiple expanding shells. Numerous diffuse interstellar bands seen in the spectra may also originate in the same shells.
Dynamics of Cosmic Neutrinos in Galaxies
Authors: Sapar A. 
Published: February 2017

AbstractThe cosmic background of massive (about 1 eV rest-energy) neutrinos can be cooled to extremely low temperatures, reaching almost completely degenerated state. The Fermi velocity of the neutrinos becomes less than 100 km/s. The equations of dynamics for the cosmic background neutrinos are derived for the spherical and axisymmetrical thin circular disk galaxies. The equations comprise the gravitational potential and gravity of the uniform baryonic disk galaxies. Then the equations are integrated analytically over the disk radius. The constant radial neutrino flux in spherical galaxies favors formation of the wide unipotential wells in them. The neutrino flux in the axisymmetrical galaxies suggests to favor the evolution in the direction of a spherically symmetrical potential. The generated unipotential wells are observed as plateaux in the velocity curves of circular stellar orbits. The constant neutrino density at galactic centers gives the linear part of the curves. The derived system of quasilinear differential equations for neutrinos in the axisymmetrical galaxies have been reduced to the system of the Lagrange-Charpit equations: the coupled differential equations, specifying the local neutrino velocities and dynamics of motion along trajectories, and an additional interconnected equation of the neutrino mass conservation, which can be applied for the determination of density of the neutrino component in galaxies.
Cosmic-Ray Induced Diffusion in Interstellar Ices
Authors: Kalvāns Juris 
Published: February 2017

AbstractCosmic rays are able to heat interstellar dust grains. This may enhance molecule mobility in icy mantles that have accumulated on the grains in dark cloud cores. A three-phase astrochemical model was used to investigate the molecule mobility in interstellar ices. Specifically, diffusion through pores in ice between the subsurface mantle and outer surface, assisted by whole-grain heating, was considered. It was found that the pores can serve as an efficient transport route for light species. The diffusion of chemical radicals from the mantle to the outer surface are most effective. These species accumulate in the mantle because of photodissociation by the cosmic-ray induced photons. The faster diffusion of hydrogen within the warm ice enhances the hydrogenation of radicals on pore surfaces. The overall result of the whole grain heating-induced radial diffusion in ice are higher abundances of ice species, whose synthesis involve light radicals. Examples of stable species synthesized this way include complex organic molecules, OCS, H
Models of Late-type Disk Galaxies: 1-D Versus 2-D
Authors: Mineikis T. , Vansevičius V. 
Published: February 2017

Abstract
We investigate the effects of stochasticity on the observed galaxy parameters by comparing our stochastic star formation two-dimensional (2-D) galaxy evolution models with the commonly used one-dimensional (1-D) models with smooth star formation. The 2-D stochastic models predict high variability of the star formation rate and the surface photometric parameters across the galactic disks and in time.
Observations of Two Unusual Eclipsing Binaries, FN Cam and AG Vir
Authors: Avvakumova E. A. , Malkov O. Yu. , Popov A. A. , Kniazev A. Yu. 
Published: February 2017

Abstract
Based on the results of classification of eclipsing binaries, we have compiled a list of stars that are promising objects for future study. We have started an observational campaign with telescopes of the Kourovka Observatory, Russia and present the first results of this work.
Medium Resolution Spectroscopy and Chemical Composition of Galactic Globular Clusters
Authors: Khamidullina D. A. , Sharina M. E. , Shimansky V. V. , Davoust E. 
Published: February 2017

Abstract
We used integrated-light medium-resolution spectra of six Galactic globular clusters and model stellar atmospheres to carry out population synthesis and to derive chemical composition and age of the clusters. We used medium-resolution spectra of globular clusters published by Schiavon et al. (2005), as well as our long-slit observations with the 1.93 m telescope of the Haute Provence Observatory. The observed spectra were fitted to the theoretical ones interactively. As an initial approach, we used masses, radii and log g of stars in the clusters corresponding to the best fitting isochrones in the observed color-magnitude diagrams. The computed synthetic blanketed spectra of stars were summed according to the Chabrier mass function. To improve the determination of age and helium content, the shape and depth of the Balmer absorption lines was analysed. The abundances of Mg, Ca, C and several other elements were derived. A reasonable agreement with the literature data both in chemical composition and in age of the clusters is found. Our method might be useful for the development of stellar population models and for a better understanding of extragalactic star clusters.
Survival Probability for a Hypervelocity Star in Close Neighborhood of a Supermassive Black Hole
Authors: Dryomova G. , Dryomov V. , Tutukov A. 
Published: February 2017

Abstract
We present the results of numerical simulation on the probability of formation of a Hypervelocity Star (HVS) in the scenario of dynamic capture of a close binary system by the central black hole in the Galaxy and on the probability of its survival in the strong tidal field in the vicinity of the black hole. The results have been obtained for a series of pericentric distances. We applied a two-level numerical simulation implemented at first in the framework of the three-body problem used for evaluation of the HVS ejection velocity and then as an N-body approach that allowed us to establish the final status of the star: the degree of its destruction and mass loss. Probability estimations are based on a statistical ensemble of 10 000 initial configurations of the close binary with respect to the orbital phase of the components as well as to the inclination of the binary orbit to the plane of the orbit around the super-massive black hole and on the ensemble of 50 configurations for the three-body and N-body approaches, respectively.
Interstellar Matter Structure along the Line of Sight to Cyg X-1
Authors: Bochkarev N. G. , Karitskaya E. A. , Klochkova V. G. , Yushkin M. V. 
Published: February 2017

Abstract
High-resolution spectra (R = 60 000) of Cyg X-1 = V1357 Cyg obtained with the NES echelle spectrograph of the Russian 6 meter telescope (3950–6690 Å) were used to study narrow interstellar absorption lines. We resolved the interstellar line blends by fitting them with Gaussian profiles. The main three absorption components, with the heliocentric radial velocities V
r = −1, −13 and −26 km s−1, were revealed. They correspond to three interstellar gas and dust complexes along the line of sight to the object. Thus, we get information on the distribution of interstellar matter along the way to Cyg X-1. The interstellar calcium abundance and ionization degree, averaged along the line of sight, were determined. A weak component with V
r = −43 km s−1 is revealed in the profiles of the strongest lines. We relate it to the approaching wall of the expanding interstellar envelope around the Cyg OB3 association (superbubble). This finding supports the view that Cyg X-1 was born in this stellar association and is still located in it.
Abundances of Chemical Elements in Open Star Clusters as Indicators of their Nature
Authors: Marsakov V. A. , Gozha M. L. , Koval’ V. V. , Shpigel’ L. V. 
Published: February 2017

Abstract
Applying a compilled catalog, we find that the relative abundances of α-elements in open clusters and in field stars of the thin disk of the Galaxy show different dependencies on metallicity, age and parameters of their Galactic orbits. The distinctions are explained by different nature of open clusters and field stars. We confirm the conclusions, reached earlier from the analysis of the parameters of Galactic orbits, that some clusters may have formed from the impact of metal-poor high-velocity clouds on the interstellar matter of the thin disk. Arguments are also adduced in favor of the formation of metal-rich high-velocity clusters from the interaction of metal-rich intermediate-velocity clouds formed from returning gas of the Galactic “fountain” with the interstellar medium of the thin disk.
A New Estimate of the Local Standard of Rest from Data on Young Objects
Authors: Bobylev V. V. , Bajkova A. T. 
Published: February 2017

Abstract
To estimate the peculiar velocity of the Sun with respect to the Local Standard of Rest (LSR), we use young objects in the Solar neighborhood with distance measurement errors within 10%–15%. These objects include the nearest Hipparcos O–B2.5 type stars, masers with VLBI trigonometric parallaxes, and two samples consisting of the youngest and middle-aged Cepheids. The most significant component of motion of all these stars is induced by the spiral density wave. An analysis of all these samples, taking into account differential Galactic rotation and the effect of the spiral density wave, yields the following components of the vector of the peculiar velocity of the Sun with respect to the LSR: (U
⊙, V
⊙, W
⊙)LSR = (6.0, 10.6, 6.5) ± (0.5, 0.8, 0.3) km s−1. We found the Solar velocity components (U
⊙)LSR and (V
⊙)LSR to be highly sensitive to the Solar radial phase χ⊙ in the spiral density wave.
Structure and Kinematics of Polar Ring Galaxies: New Observations and Estimation of the Dark Halo Shape
Authors: Moiseev A. , Khoperskov S. , Khoperskov A. , Smirnova K. , Smirnova A. , Saburova A. , Reshetnikov V. 
Published: February 2017

Abstract
The polar ring galaxies (PRGs) represent an interesting type of peculiar systems in which the outer matter is rotating in the plane which is roughly perpendicular to the disk of the main galaxy. Despite the long-lasting study of the PRGs, the amount of observational data detailed enough is insufficient; there still remain many open questions. Among the most interesting issues, there are: estimating the flattening of dark matter halos in these systems and verifying the assumption that the most massive polar structures were formed by accretion of the matter from intergalactic filaments. The new catalog recently compiled by our team using SDSS images increased, by several times, the number of known PRGs. The current paper gives an overview of our latest results on the study of morphological and photometric structure of the PRGs. Using the stellar and ionized gas kinematics data based on spectroscopic observations with the Russian 6-m telescope, we estimate the shape of dark matter halo in individual galaxies.
The Possibility of a Deep Scanning Survey of Part of the Sky from a Low-Orbit Spacecraft with Fixed Orbital Orientation
Authors: Prokhorov M. E. , Zakharov A. I. , Mironov A. V. , Biryukov A. V. , Stekol’shchikov O. Yu. , Tuchin M. S. , Zhukov A. O. 
Published: February 2017

Abstract
We analyze the possibility of performing a deep survey of a part of the sky near the poles of the spacecraft orbit from a low-orbit spacecraft with fixed orbital orientation. The survey depth can be increased by several magnitudes by reducing the surveyed sky area to strips along one or two minor circles at constant declination. The surveyed area is scanned by precession of the spacecraft.
UBVJHKLM Photometry and Low-Resolution Spectroscopy of Nova Delphini 2013 (V339 Del)
Authors: Burlak M. A. , Esipov V. F. , Komissarova G. V. , Shenavrin V. I. , Taranova O. G. , Tatarnikov A. M. , Tatarnikova A. A. 
Published: February 2017

Abstract
We present UBVJHKLM photometric observations of Nova Delphini 2013 that started several hours before maximum light and lasted for 130 nights. Using the obtained data, we derived several photometric parameters of the Nova: the time of maximum light, brightness at maximum, rate of decline, t
2 = 11 d. This places Nova Del 2013 among fast novae according to the classification introduced by Payne-Gaposchkin. We estimated the interstellar reddening EB−V
= 0.18 using maps of Galactic extinction and the absolute brightness in maximum light via the MMRD relation that allowed us to determine the distance D ≈ 2.7 kpc and height above the Galactic plane z ≈ 440 pc. Low-resolution spectroscopy shows that Nova Del 2013 belongs to the Fe II spectral type of novae. The broad emission feature near 6825 Å observed during 2013 August and September may be the Raman-scattered OVI 1032 Å line.
Detection of Unresolved Binaries with Multicolor Photometry
Authors: Chulkov D. , Prokhorov M. , Malkov O. , Sichevskij S. , Krussanova N. , Mironov A. , Zakharov A. , Kniazev A. 
Published: February 2017

Abstract
The principal goal of this paper is to specify conditions of detection of unresolved binaries by multicolor photometry. We have developed a method for estimating the critical distance at which an unresolved binary of given mass and age can be detected. The method is applied to the photometric system of the planned Lyra-B spaceborne experiment. We have shown that some types of unresolved binary stars can be discovered and distinguished from single stars solely by means of photometric observations.
On Equilibrium Figures of Particle Clouds around the Sun and Stars
Authors: Kondratyev B. P. , Trubitsina N. G. 
Published: February 2017

Abstract
Equilibrium figures of cold gas-dust (or cometary) clouds are studied in a more general setting than the classical Roche problem. The cloud is considered to be under the influence of gravitational attraction of the central star and the tidal field of the Galaxy. Our analysis also takes into account the centrifugal forces due to the rotation of the cloud, which moves around the center of the stellar system together with the star. The limit equilibrium figure is found to have three planes of symmetry and to be shaped like a “lemon” with lateral swellings and two singular points. The shape of this figure and its cusp angles in the planes of two main sections are calculated. The average density inside the equilibrium figure is shown to be almost exactly equal to the average density of matter in the Galaxy. This coincidence cannot be accidental and means that equilibrium figures with the critical level of the total surface potential fill the entire volume of the Galaxy. A possible consequence is that the cometary clouds of neighboring stars in the Galaxy may touch each other (or even intersect because of the presence of dark matter). Hence stars may exchange comets and part of the comets in the Solar System may belong to other stars.
Velocity Dispersion of Ionized Gas and Multiple Supernova Explosions
Authors: Vasiliev E. O. , Moiseev A. V. , Shchekinov Yu. A. 
Published: February 2017

Abstract
We use 3D numerical simulations to study the evolution of the Hα intensity and velocity dispersion for single and multiple supernova (SN) explosions. We find that the I
Hα
– σ diagram obtained for simulated gas flows is similar in shape to that observed in dwarf galaxies. We conclude that colliding SN shells with significant difference in age are responsible for high velocity dispersion that reaches up to ≳ 100 km s−1. Such a high velocity dispersion could be hardly obtained for a single SN remnant. Peaks of velocity dispersion in the I
Hα
– σ diagram may correspond to several isolated or merged SN remnants with moderately different ages. Degrading the spatial resolution in the Hα intensity and velocity dispersion maps makes the simulated I
Hα
– σ diagrams close to those observed in dwarf galaxies not only in shape, but also quantitatively.