Arctic meiofauna and nematodes were examined at 12 stations in the East Siberian Sea, covering a depth range of 13-59 m and an estuarine-shelf system from the Indigirka and Kolyma rivers to the ...adjacent shelf. Our data reveal the low diversity of the meiofauna at the East Siberian Sea shelf. The meiobenthos abundance was influenced by river run-off and the sea bottom landscape. The samples comprised a total of 28 families and 72 genera, and the number of genera per station ranged from 15 to 32. The Comesomatidae was the dominant family with genus Sabatieria. Among all factors, depth, water temperature and the total organic carbon appeared to be important variables explaining spatial variations in meiofauna and nematodes abundance. Depth and river run-off were defining in controlling the density of nematodes in the study area.
The effect of random one- (1D) and two-dimensional (2D) inhomogeneities of the magnetic anisotropy on the shape and width of ferromagnetic resonance line in a thin film has been studied in the ...standard and new self-consistent approximations. It has been shown that resonance peaks in the case of 2D inhomogeneities are much narrower than those for 1D ones. Peaks are asymmetric in both the 1D and 2D cases, but asymmetry is larger in the latter case. As the correlation wavenumber of inhomogeneities
k
c
increases, the width of a resonance line decreases and its amplitude increases. The amplitude of the FMR peak for 2D inhomogeneities increases much faster than that for 1D inhomogeneities. At the critical dimensionless parameter
k
c
d
/π ~ 1, where
d
is the thickness of the film, the width of the resonance line has an inflection point and the asymmetry of this line and the shift of the ferromagnetic resonance peak are maximal. It has been shown that the new self-consistent approximation reproduces the shape of the resonance line much better than the standard self-consistent approximation.
This paper focuses on the problem of the high financial risks of agricultural entrepreneurship, which hinder the sustainable development of agriculture and do not provide food security. This problem ...is especially topical in the conditions of the COVID-19 crisis when financial risks are urgent. The research basis is the theory of financial risks of entrepreneurship. This paper's RQ is as follows: how should financial risks for the sustainable development of agriculture be managed for the provision of food security? The purpose of this paper is to find ways of managing the financial risks of agricultural entrepreneurship based on its corporate social responsibility for sustainable development and the provision of food security. The contribution to the literature is that the authors offer a solution to the problem of the financial risks of agricultural entrepreneurship. The originality of this paper is that the solution is corporate social responsibility. The universal character of the paper is due to the description of the international experience of corporate social responsibility and proving the contribution of this responsibility for the sustainable development of agriculture and food security as well as its demonstration-based on the case experience of modern Russia of specific, effective, and perspective practices of corporate social responsibility that make a significant contribution to the sustainable development of agriculture and food security. The results are very important for decision making in managing the financial risks of agricultural entrepreneurship.
Abstract
The paper considers the current situation in the Russian Federation of such a crop as peas. Data on the area of crop cultivation is presented not only in the world, but also in the context ...of Federal districts and regions. In the world, the main producers of peas are countries such as Canada, Russia, China and India. In the Russian Federation, the main areas under crop are located in the Volga, Siberian, Southern and Central Federal districts. They are also leaders in the gross harvest of pea grains. It also shows data on the yield of peas sown in the leading regions of Russia for several years, which allows assessing more accurately the value of this indicator. So the highest yield of peas is obtained in the Oryol and Kursk regions, as well as in the Krasnodar territory. The dynamics of inclusion of pea breeds in the State register of breeding achievements allowed for use is analyzed. As before, national breeds prevail over foreign ones in terms of the total number in the register, but producers prefer Western European varieties to a greater extent. Due to its self-sufficiency in peas, Russia is an exporter to countries such as Spain, India, Turkey, Italy, etc. The reasons for the low competitiveness of national breeds are indicated.
The crossing resonance of two wavefields
m
(
x
,
t
) and
u
(
x
,
t
) of different natures in an inhomogeneous medium with zero mean value of the coupling parameter η between fields has been studied. ...The stages of formation of the fine structure of the crossing resonance have been analyzed. It has been shown within the model of independent crystallites that the removal of the degeneracy of eigenfrequencies of these fields at the crossing resonance point has a threshold character in the coupling parameter and occurs under the condition η > η
c
, where η
c
= |Γ
u
– Γ
m
|/2, Γ
u
and Γ
m
are the relaxation parameters of the corresponding wavefields. At η > η
c
, each random implementation of the Green’s functions
and
of wavefields has the form of two resonance peaks with the same half-width (Γ
u
+ Γ
m
)/2 spaced by the interval 2η; this form is standard for crossing resonances. At η < η
c
, the functions
and
are different: if Γ
u
> Γ
m
, the function
has the form of a narrow resonance peak at ω = ω
r
, whereas the function
has the form of a broader resonance peak split at the top by a narrow antiresonance. Averaging over regions where η > η
c
leads to the formation of a broad resonance with a resonance line half-width of about 〈η
2
〉
1/2
on the both averaged Green’s functions, which is due to the stochastic distribution of resonance frequencies. Averaging over regions where η < η
c
results in the sharpening of a resonance peak on the function
and an antiresonance peak on the function
at the same frequency ω = ω
r
. As a result, a pattern of the crossing resonance in the inhomogeneous medium is formed, consisting of identical broad peaks on both functions with the narrow resonance peak of the fine structure on the function
and the antiresonance peak on the function
. Thus, the fine structure of the spectrum of any crossing resonance of two wavefields of different natures in the inhomogeneous medium is due to the contribution of random realizations corresponding to degenerate states of the natural oscillations of the system. In a ferromagnet with a spatially inhomogeneous coupling parameter, spin and elastic waves acquire damping parameters Γ
m
(
k
) ∝
k
c
and Γ
u
(
k
) ∝
k
c
proportional to the correlation wavenumber
k
c
of inhomogeneities and to the velocities of the corresponding waves, which are summed with the homogeneous damping parameters Γ
m
and Γ
u
of the same waves. This situation has been considered in a new self-consisting approximation for the case where the contribution of homogeneous damping parameters is negligibly small. It has been shown that the form of the fine structure on the functions
and
at the second (high-frequency) crossing point of dispersion curves of spin and elastic waves changes to the opposite form: narrow resonance peaks of the fine structure appear on the function
, and antiresonance peaks arise on the function
because
<
and
>
at the first and second crossing points, respectively.
Processes of amorphization and crystallization of binary and multicomponent melts based on transition metals are studied. Comparative analysis of the pre-crystallization structural changes and of the ...atomic dynamics under the conditions of forced quenching and deep supercooling of metallic melts is performed. It is shown that hydrogenation of the melts introduces specific features into the occurrence of the pre-recrystallization processes by affecting the atomic configuration, the modulation of the frequency spectrum and the fluctuation of the energy-band (electron) structure determining the vitrification and the coherent nanocrystallization with combination of crystal clusters and clusters with noncrystallographic symmetry.
An analysis of synthesized unique two-dimensional 2D materials with nanolayer hexagonal and pentagonal structures (based on carbon, silicon, tin, binary compounds CN2, BN2, PdSe2 and ternary ...compounds – BCN, CNP, PdSSe, Zn2C2P2) was carried out. The synthesis of these materials was performed by the chemical vapor deposition or metal epitaxy on pre-prepared substrates. The strength and functional characteristics (electronic, optical) of the created models were also analyzed using the DFT theory in the form of triple monolayers with double-sided deposition of hydrogen on the surface of the p-Si2C4 monolayer: hydrogen/p-Si2C4/hydrogen. It was found that the p-Si2C4-4H layer with its two-sided hydrogen adsorption and good properties was the most dynamically stable. This article also presents relatively recently obtained hexa- and pentagonal two-dimensional materials not only for the elements C, Si, Ge, B, but also for Cu1–xNix, Ti1–xNix alloys and Bi1–xSbx, CN2, BN2, PdSe2, etc. compounds. So, with the new unique materials created – the synthesis of superstrong, thermostable nanocomposites, superconducting layered composites (based on Bi, Hg and Sb), prospects are opening up for the development of nanoelectronics, spintronics, computer technology, as well as the creation of portable strain gauges, pressure sensors, gas sensors and dialysis catalysts for water dialysis with the release of hydrogen and oxygen.
The carbon dioxide concentration in the atmosphere has progressively risen since pre-industrial times. About one-third of the anthropogenically generated CO2 is absorbed by the waters of the World ...Ocean, whereas the waters of the Southern Ocean take up about 40% of this CO2. The concentrations of oxygen and carbon dioxide dissolved in seawater are sensitive to climate changes, transferring anthropogenic pressures with consequences for the biogeochemical cycles in the World Ocean. The Southern Ocean is a key region for the exchange of oxygen and carbon between the surface water and the atmosphere and for their transfer with cold water masses to the deep layers of the Ocean. In this paper, we discuss the dynamics of the carbon dioxide partial pressure (pCO2) and dissolved oxygen (O2) in the surface waters of the Atlantic Southern Ocean based on data collected during the 87th cruise of the R/V “Academik Mstislav Keldysh”. The study area includes the Bransfield Strait, Antarctic Sound, the Powell Basin, the Weddell, and Scotia Seas. We have analyzed the spatial distribution of pCO2 and oxygen for the areas of transformation of water masses and changes in biogeochemical processes. In the zone of Scotia and Weddell Seas, we have observed an increase in pCO2 and a decrease in oxygen concentrations at the transect from the Weddell Sea at 56° W to the Powell Basin. From the Antarctic Sound to the Bransfield Strait, a decrease in oxygen saturation and an increase in pCO2 has been traced. The surface waters of the Bransfield Strait have revealed the greatest variability of hydrochemical characteristics due to a complex structure of currents and intrusions of different water masses. In general, this area has been characterized by the maximum pCO2, while the surface waters are undersaturated with oxygen. The variability of the AOU/ΔpCO2 (w-a) ratio has revealed a pCO2 oversaturation and an O2 undersaturation in the waters of the Bransfield Strait. It is evidence of active organic carbon decomposition as the major controlling process. Yet, photosynthesis is the major biogeochemical process in the studied areas of the Weddell and Scotia seas, and their waters have been undersaturated with pCO2 and oversaturated with O2. As it comes from the analysis of the distribution and correlation coefficients of AOU and the sea-air gradient of pCO2 with other physical and biogeochemical properties, the predominance of the biotic processes to the dynamics of O2 and pCO2 in the surface water layer has been demonstrated for the studied areas. Yet, there is evidence of additional sources of CO2 not associated with the production and destruction processes of organic matter.
•Three types of catalysts with hierarchical porosity have been developed.•Catalysts are active and stable in atmospheric and vacuum residues hydroprocessing.•Catalysts had slight deactivation due to ...coke and metal depositions up to 1420 h.•Optimal operation parameters for each stage of the processes were revealed.•A pilot setup for three-stage hydroprocessing of oil residues has been developed.
The study is devoted to the tests of hierarchical meso-macroporous catalysts for three-stage atmospheric and vacuum residues hydroprocessing. A special attention is paid to properties of fresh and spent catalysts, the results of experiments on the selection of the optimal parameters (T, p and LHSV) for the three-stage hydroprocessing of residues, as well as the properties of petroleum products produced under optimal conditions. Catalysts were characterized with XRD, nitrogen adsorption–desorption, Hg-intrusion, SRXRF, TPD-NH3 and SEM. The proposed technology of the hydroprocessing of residues over the catalysts with hierarchical porosity makes it possible to obtain valuable oil products and MARPOL marine fuel, which meets modern technical and environmental requirements. Based on the laboratory experiments, a pilot setup for three-stage hydroprocessing of residues has been developed, and is tested at the moment.
PDF
