153 research outputs found
On gravitational flow in the Relativistic Theory of Gravitation
A definition of the gravitational flow and a short description of the recipe
of its calculation are presented.Comment: 6 page
Electron mass operator in a strong magnetic field
The electron mass operator in a strong magnetic field is calculated by
summation of the leading log contributions in all orders of the perturbation
theory. An influence of the strong field on the virtual photon polarization
operator is taken into account. The contribution of higher Landau levels of
virtual electrons, along with the ground Landau level, is shown to be essential
in the leading log approximation.Comment: 7 pages, LATEX, 1 PS figure, submitted to Modern Physics Letters
Diagnosing magnetars with transient cooling
Transient X-ray emission, with an approximate t^{-0.7} decay, was observed
from SGR 1900+14 over 40 days following the the giant flare of 27 Aug 1998. We
calculate in detail the diffusion of heat to the surface of a neutron star
through an intense 10^{14}-10^{15} G magnetic field, following the release of
magnetic energy in its outer layers. We show that the power law index, the
fraction of burst energy in the afterglow, and the return to persistent
emission can all be understood if the star is composed of normal baryonic
material.Comment: 9 pages, 1 eps figur
Gravitational Waves in Relativistic Theory of Gravitation
It is shown that, in the framework of Relativistic Theory of Gravitation with
massive graviton, gravitational waves, due to the causality condition, do not
bear negative energy flows.Comment: 4 page
The results of orthotopic heart transplantation using the bicaval technique
Circulatory failure, which develops in the final stages of the course of the most heart diseases, is a link in the progressive process. This process is accompanied by a significant decrease in the quality of life, as well as high disability and mortality.
Heart transplantation increases the survival of patients with chronic heart failure, increases tolerance to physical exertion, improves the quality of life of patients and allows most of them to return to vigorous activity.
Aim. The work is devoted to the analysis of the results of orthotopic heart transplantation in patients with a progressive course of chronic heart failure that cannot be treated conservatively.
Materials and methods. We analyzed the clinical course of heart transplants in 55 patients. There were 46 (83.6 %) men and 9 (16.4 %) women among the recipients. The average age was 46.0 ± 10.0 years.
Results. The result of the conducted retrospective study revealed that in-hospital (early) and one-year (longterm) survival among patients in our study was 92.7 % and 81.8 %, respectively.
Conclusions. Heart transplantation is the most effective method of treatment for terminal heart failure. The quality of life of heart transplant patients improves significantly after surgery and is the main factor in the development of heart transplantation nowadays.
The main causes of death were acute graft dysfunction, rejection reactions, and coronary heart disease of the transplanted heart. Problems related to cardiac graft dysfunction and rejection in the early and long-term period still need to be definitively resolved
Histological characteristics and functional properties of red and white parts of m. semitendinosus of slaughter pigs
A unique muscle of pigs (Sus scrofa domesticus) is m. semitendinosus, which contains the “red” (dark) part located mainly in the depth of the leg cut and the “white” (light) part located in the close proximity to the subcutaneous fat layer. Differences in the characteristics of its “red” and “white” parts can exert a significant effect on quality and economic indicators of meat products. The aim of this research was to study histological features of the microstructure and technological properties of muscle tissue from different parts of m. semitendinosus, obtained from slaughter pigs of Russian production. M. semitendinosus was excised from chilled porcine carcasses (N=20) 24 hours after slaughter in the process of deboning. Histological examination showed that the dark part of the muscle was characterized by a higher package density of fibers, higher number of capillaries and higher sarcomere length. On the contrary, the light part was characterized by a higher diameter of muscle fibers. Analysis of muscle fiber types showed that the proportion of type I, intermediate and type IIb fibers was higher by 9.3, 5.2 and 4.1%, respectively, in the dark part. Significant differences between the dark and light parts of m. semitendinosus were revealed in terms of the number and size of giant fibers: the light part was characterized by a larger number (by more than 5 times) of giant fibers with the fibers of a larger size (almost by 11%). The samples of minced meat from the dark and light parts showed significant (р<0.05) differences in the mean values of lightness, redness and yellowness (L*, a* and b*) by 6.00, 4.68 and 3.01 units, respectively, in raw samples, and by 6.53, 2.99 and 1.81, respectively, after curing with the nitrite mixture and cooking (р<0.05). The dark part of m. semitendinosus had higher pH values (р<0.05) both for raw and cooked samples. The consistency of the samples from the light part was less elastic, looser and more crumbly than that in the samples produced from the dark part of m. semitendinosus, which was confirmed by the structural-mechanical investigations. Therefore, this study showed significant differences between the dark and light parts of m. semitendinosus by microstructural and functional-technological characteristics. Significant variability by muscle fiber diameter, which was observed in the light part of this muscle, apparently should be taken into account in breeding work and quality assessment of pork from slaughter animals
Atomic levels in superstrong magnetic fields and D=2 QED of massive electrons: screening
The photon polarization operator in superstrong magnetic fields induces the
dynamical photon "mass" which leads to screening of Coulomb potential at small
distances , is the mass of an electron. We demonstrate that this
behaviour is qualitatively different from the case of D=2 QED, where the same
formula for a polarization operator leads to screening at large distances as
well. Because of screening the ground state energy of the hydrogen atom at the
magnetic fields has the finite value .Comment: 12 pages, 2 figure
Tunable Fermi acceleration in the driven elliptical billiard
We explore the dynamical evolution of an ensemble of non-interacting
particles propagating freely in an elliptical billiard with harmonically driven
boundaries. The existence of Fermi acceleration is shown thereby refuting the
established assumption that smoothly driven billiards whose static counterparts
are integrable do not exhibit acceleration dynamics. The underlying mechanism
based on intermittent phases of laminar and stochastic behavior of the strongly
correlated angular momentum and velocity motion is identified and studied with
varying parameters. The diffusion process in velocity space is shown to be
anomalous and we find that the corresponding characteristic exponent depends
monotonically on the breathing amplitude of the billiard boundaries. Thus it is
possible to tune the acceleration law in a straightforwardly controllable
manner
Aluminum tolerance and micronutrient content in the grain of oat cultivars with different levels of breeding improvement from the VIR collection
Background. Soil toxicity of Al is associated with severe changes in plant root morphology that limit the uptake of water and mineral nutrients. Long-term exposure to Al results in deficiencies in some important nutrients, such as phosphorus, calcium, magnesium, potassium, and iron. Thus, the joint study of plant resistance to the effects of Al and the accumulation of micronutrients in the oat grain is relevant.Materials and methods. Thirty oat accessions of Russian and French origin from the VIR collection served as the research material. They were represented by cultivars with different levels of breeding improvement: landraces (early 1920s), cultivars developed by primitive breeding (1920–1930s), and modern improved cultivars.Results. Oat cultivars with different breeding improvement levels demonstrated significant differences in the content of micronutrients and aluminum tolerance. Among the studied accessions, landraces and modern improved cultivars showed a tendency towards medium or high Al tolerance, the group of primitive cultivars from Russia had the lowest Al tolerance, while primitive cultivars from France demonstrated the highest average resistance (0.5–1.9).Conclusion. The content of Fe and Zn was influenced by the geographic origin of genotypes. The concentrations of different micronutrients positively correlated with each other. Strong correlations were recorded between the contents of Zn and Fe (r = 0.81), and between Zn and Mg (r = 0.75). There was a positive correlation between the content of micronutrients and the resistance to crown rust (0.38 to 0.50). High content of the studied set of micronutrients was registered in such improved cultivars from France as the naked ‘Avoine Nue Renne’, ‘Chantilly’, ‘Negrita’ and ‘Noire de Michamps’, plus the Russian improved naked cultivar ‘Gavrosh’. Among them, ‘Chantilly’ was distinguished for its yield, and the naked ‘Gavrosh ‘for its high tolerance to aluminum
Modification of Coulomb law and energy levels of the hydrogen atom in a superstrong magnetic field
We obtain the following analytical formula which describes the dependence of
the electric potential of a point-like charge on the distance away from it in
the direction of an external magnetic field B: \Phi(z) = e/|z| [ 1-
exp(-\sqrt{6m_e^2}|z|) + exp(-\sqrt{(2/\pi) e^3 B + 6m_e^2} |z|) ]. The
deviation from Coulomb's law becomes essential for B > 3\pi B_{cr}/\alpha = 3
\pi m_e^2/e^3 \approx 6 10^{16} G. In such superstrong fields, electrons are
ultra-relativistic except those which occupy the lowest Landau level (LLL) and
which have the energy epsilon_0^2 = m_e^2 + p_z^2. The energy spectrum on which
LLL splits in the presence of the atomic nucleus is found analytically. For B >
3 \pi B_{cr}/\alpha, it substantially differs from the one obtained without
accounting for the modification of the atomic potential.Comment: version to be published in Physical Review D (incorrect "Keywords" in
previous version have been cancelled
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