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Calculations of the spectral coefficients for X-ray absorption and spectral brightness's for X-ray radiation were performed for niobium Z-pinch plasma at the temperature of 1 keV and at different plasma densities to determine the compression degree where the spectral lines become indistinguishable. As known, traditional methods of temperature diagnostics of hot dense radiating plasmas are based on analysis of the spectral line shape in dependence on plasma temperature and density. In this case, the interval of photon radiation energies is used, where the spectral lines are well distinguishable in an experiment. On the other hand, Z-pinch plasma has high compression, and an increase of plasma density leads to the deformation of the spectral line shape because of Doppler broadening, Stark broadening, and so-called “additional” broadening of spectral lines that take place in a quantum statistical ensemble of plasma ions and atoms. The traditional method of temperature diagnostics becomes impossible and different methods, which do not use spectral line characteristics, should be applied. The aim of this paper is to determine the density border where the spectral lines become indistinguishable. Important features of the quantum mechanical model, which is known as ion model of plasma, and which is used for calculations in the presented paper, are considered and discussed. A brief review of the theoretical models that have been earlier developed to calculate the radiative opacity characteristics of hot dense plasma is presented as well.
We propose three calibration scenarios of to date contemporary divergence of Anoplopomatidae (skilfish Erilepis zonifer and sablefish Anoplopoma fimbria) for a data set of two mtDNA loci (СOI and Control Region). The first scenario is based upon a fossil record and the second and third ones upon major palaeogeological events 3.5 and 15 Mya. Estimated evolution speeds indicate that COI evolves faster in the skilfish mitochondrial genome. There is also evidence of skilfish going through a bottleneck event limiting its genetic diversity in the relatively recent past near Japan. Sablefish had two refugia on both sides of the Pacific Ocean. The contemporary haplotype divergence was formed ~450 thousand years ago during an ice age in the Pleistocene and contemporary populations display no apparent geographic differentiation.
For the first time, the results of the study of the age and growth of blue hake Antimora rostrata in the waters of the Lazarev and Weddell seas (Antarctic) are presented. The longline catches were represented by fish from 42 to 69 cm in total length with weights between 420 and 2,900 g, and most individuals aged 25 to 27 years. A minimum age of 16 years was observed in a fish 47 cm long and weighing 450 g, while a maximum age of 35 years was recorded for an individual of 69 cm in length and 1,640 g in weight. The blue hake in the Lazarev and Weddell seas shows similar growth patterns to the fish from the Ross Sea and waters off Greenland.
The galactocentric motion of 14 stars from the solar neighbourhood is studied. The stars are divided into nine groups according to their heliocentric-velocity components. In this way one can follow the motion of the stars belonging to the same group in the past.
We computed the dynamical evolution of hierarchical triple stars in which both orbits are initially circular, and determine the lower limit to the ratio of periods (outer/inner) for which there is dynamical stability. We found for some mass ratios resonance-like behaviour that occurs in a limited range of initial period ratio. Some resonances are ‘disruptive’; that is, for a small range of initial period ratio we find that the system is not able to settle down to a quasi-steady hierarchical state, but instead disrupts. However, below as well as above this disruptive range there are considerable ranges of initial period ratio where the hierarchical state appears to be stable, at least for the length of integration time we took which was sometimes as much as 10,000 outer orbits. The mass ratios are identified for which different types of unstable behaviour, such as an escape of the distant body without exchange, many exchanges in the limited space without escape, formation of new long-live hierarchy, or an escape of one body after a few exchanges, occur for ratios of periods slightly below the limit of stability. We discuss the relevance of the above behaviour to observed close triples, the closest of which is λ Tau (period ratio 8.3).
The triple star system αCen AB and Proxima Cen - the component C - is the nearest to the Sun. The study of its dynamics has shown that this system is probable non-chance. The motion of the component C (Proxima) with respect to the centre of mass of the pair AB is hyperbolic with the probability P = 1.0. We observe, therefore, a slow passage of C close to the pair AB. We propose the hypothesis that this system is a part of the stellar moving group. We list the probable members of this group amongst the nearby stars. Amongst them we have the binaries Gliese 140.1 and 676, the triple system ADS 10288 (Gliese 649.1), and the six single stars. The probability to find by chance these stars inside the velocity space cube with the side of 20 km/s around αCen is equal to about 2%.
Moringa oleifera is a rich source of antioxidants and a promising feed for livestock, due to significant amounts of protein, vitamins, carotenoids and polyphenols, and negligible amounts of anti-nutritional factors. The current study tested whether ensiling would preserve the antioxidant capacity of M. oleifera plants, and assessed whether Moringa silage, fed as a substitute for maize silage, would confer health-promoting traits and affect milk production in dairy cows. To this end, hand-harvested M. oleifera plants were ensiled, with or without molasses and inoculants, in anaerobic jars at room temperature (25 °C) for 37 days. At the end of the storage period the silages were analysed for pH, lactic acid and acetic acid concentrations, aerobic stability, antioxidant capacity, polyphenols and protein content, and tocopherols and carotenoids concentrations. Moringa silages exhibited higher antioxidant capacity compared with fresh and dried Moringa plants, not related to polyphenol content but presumably attributed to accumulation of amino acids and low molecular weight peptides. Based on these findings, a large-scale ensiling protocol was implemented, followed by a feeding trial for dairy cows, in which Moringa silage replaced 263 g maize silage/kg in the diet. Cows fed Moringa silage had higher milk yield and antioxidant capacity and lower milk somatic cell counts compared with controls, during some stages of lactation. These findings imply that ensiling M. oleifera is an appropriate practice by which health and production of dairy cows can be improved.
Advanced reduced activation ferritic/martensitic steels and oxide dispersion-strengthened steels exhibit significant radiation embrittlement under low temperature neutron irradiation. In this study we focused on atom probe tomography (APT) of Eurofer97 and ODS Eurofer steels irradiated with neutrons and heavy ions at low temperatures. Previous TEM studies revealed dislocation loops in the neutron-irradiated f\m steels. At the same time, our APT showed early stages of solid solution decomposition. High density (1024 m–3) of ∼3–5 nm clusters enriched in chromium, manganese, and silicon atoms were found in Eurofer 97 irradiated in BOR-60 reactor to 32 dpa at 332°C. In this steel irradiated with Fe ions up to the dose of 24 dpa, pair correlation functions calculated using APT data showed the presence of Cr-enriched pre-phases.
APT study of ODS Eurofer found a significant change in the nanocluster composition after neutron irradiation to 32 dpa at 330 °C and an increase in cluster number density. APT of ODS steels irradiated with Fe ions at low temperatures revealed similar changes in nanoclusters.
These results suggest that irradiation-induced nucleation and evolution of very small precipitates may be the origin of low temperature radiation embrittlement of f\m steels.
This work has been made in accordance with the plan of the International Working Group “Double Stars: HIPPARCOS Input Catalogue Consortium.” The precise coordinates for the components of the triple stars from the programs of the Astronomical Observatory (AO) of Leningrad State University (LSU) and the Uccle zone (declination from +30° to +50°) are determined. The work has been made by two methods: (1) special astrometrical observations for about 70 triple stars; some colleagues from the observatories in Pulkovo, Nikolaev, and Goloseevo (USSR), as well as from Belgrade (Yugoslavia) have taken part in this work; (2) statistical treatment for about 200 triple stars, using the data of the catalogues ADS and WDS—all available positional observations of the relative coordinates of the components.
Also, the special observations of the triple stars in Pulkovo and Belgrade have been used, as well as the data from the catalogue by Ch. Worley from 1820 to 1988. The old observations by W. Struve in 1820-1830 play an important role. The data obtained are used for the compilation of the observational programs of the AO of LSU by the HIPPARCOS and HST.
Triple stars and galaxies are referred to as having hierarchical or non-hierarchical structure. Thus, the dynamically stable and unstable triple systems are usually distinguished observationally by the ratio of the larger and smaller angular separation. However, (i) projection effects may hide the true configuration; and (ii) apparent hierarchical forms may occur in both types (Anosova 1986).
In consequence of the decision made by the Fifth General Assembly of the I.A.U. I have been entrusted, from January 1936, with the direction of the Central Bureau for the International Service of Latitudes.
I am much indebted to Prof. Kimura, who preceded me as Director and to Prof. Kohlschütter, Director of the Geodetic Institute of Potsdam, for information and advice, which has been of great assistance to me; therefore I desire to acknowledge to them my deep gratitude.
Depuis le Congrès de 1935, au cours duquel la Commission 15 fut créée, des travaux de plus en plus nombreux ont été effectués sur les sujets rentrant dans le cadre de cette Commission. Quoique aucune grande comète ne soit apparue pendant les trois années 1935-36-37, deux comètes moyennes visibles à l’œil nu: Peltier (1936a) et Finsler (1937f) ont permis des recherches variées auxquelles il faut ajouter celles qu’on a pu faire sur les comètes plus faibles ou moins bien placées: Johnson (1935a), Whipple (1937b), Wilk (1937c) et Encke (1937h). Des études théoriques et statistiques et des ouvrages d’ensemble ont complété ces travaux.
The purpose of this work is a verification of the virial mass estimations for small galaxy groups. The dynamical evolution of triple and quintuple galaxies has been studied by the numerical simulations. The dependence of the virial coefficient k(t) versus time was derived. Initially k(0) = 0. The function k(t) has some strong oscillations from 0.02 to 0.99. Generally, these oscillations are quasiperiodical ones. Such a behavior of k(t) is caused by formation in a system of close isolated temporary double subsystems. A strong correlation between the virial coefficient and the least mutual distance in the system is observed.
The dynamical instability of motions is studied numerically for the triplets of stars and galaxies. The models of equal-mass components which are in rest initially, are investigated. The divergence of initially near by trajectories close to exponential one is observed in the configurational as well as the phase space. The characteristic time of such divergenee is less for the configurations which are initially hierarchical. The presence of significant dark matter distributed over the whole volume of system speeds up the rate of stochastisation considerably.
By the computer simulations we have studied a behaviour of the virial coefficient k(t) for the triples and quintets of galaxies as a function of time. In a number of cases some quasiperiodical oscillations k(t) have been observed; these variations are resulted from an existence of the temporary binary subsystems. Strong negative correlation between k and rmin (rmin is a minimum separation between the bodies) is observed. A presence of a large hidden mass Mn distributed around a triple increases the degree of stochasticity of the process k(t) and decreases the correlation between k and rmin. The process k(t) must not been considered as a random one, as the autocorrelation function does not show any decreasing of the oscillation amplitude with a grow of time.
We study a process of stochastization of the motions in an example of the Henon-Heiles model. We propose a new method to study this process a method of the field of directions of motion in the meridional plane. A numerical integration of the equation for the derivative of this field ∂f/∂n to the normal to a trajectory has been made. We denote the points in which ∂f/∂n → ± ∞, and derive the contours of orbit and folds of directions. The growth of ergodity is connected with the increase of a number and an area of the folds. May be, a successive doubling of a number of folds takes place that results in a chaos. In the transition region we found a complex periodical orbit. The interpretation of this fact may be made as an example of cantori. A transition region has very small sizes about 10−4
Two methods are proposed for describing the distributions of the triplet configuration parameters characterizing a tendency to alignment and hierarchy: (1) obtaining a representative sample of configurations and determining its statistical parameters (moments and percentages); and (2) dividing the region of possible configurations of triple systems (Agekian and Anosova, 1967) into a set of segments and finding the probabilities for the configurations to find themselves in each of them.