Electron Mass Operator in a Strong Magnetic Field and Dynamical Chiral Symmetry Breaking

The electron mass operator in a strong magnetic field is calculated. 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. The effect of the electron dynamical mass generation by a magnetic field is investigated. In a model with N charged fermions, it is shown that some critical number N_{cr} exists for any value of the electromagnetic coupling constant alpha, such that the fermion dynamical mass is generated with a doublet splitting for N < N_{cr}, and the dynamical mass does not arise at all for N > N_{cr}, thus leaving the chiral symmetry unbroken.Comment: 4 pages, REVTEX4, 3 figure

Recurrence of particles in static and time varying oval billiards

Dynamical properties are studied for escaping particles, injected through a hole in an oval billiard. The dynamics is considered for both static and periodically moving boundaries. For the static boundary, two different decays for the recurrence time distribution were observed after exponential decay for short times: A changeover to: (i) power law or; (ii) stretched exponential. Both slower decays are due to sticky orbits trapped near KAM islands, with the stretched exponential apparently associated with a single group of large islands. For time dependent case, survival probability leads to the conclusion that sticky orbits are less evident compared with the static case.Comment: 7 pages, 6 figures, to appear in Phys Lett

Classical motion in force fields with short range correlations

We study the long time motion of fast particles moving through time-dependent random force fields with correlations that decay rapidly in space, but not necessarily in time. The time dependence of the averaged kinetic energy and mean-squared displacement is shown to exhibit a large degree of universality; it depends only on whether the force is, or is not, a gradient vector field. When it is, p^{2}(t) ~ t^{2/5} independently of the details of the potential and of the space dimension. Motion is then superballistic in one dimension, with q^{2}(t) ~ t^{12/5}, and ballistic in higher dimensions, with q^{2}(t) ~ t^{2}. These predictions are supported by numerical results in one and two dimensions. For force fields not obtained from a potential field, the power laws are different: p^{2}(t) ~ t^{2/3} and q^{2}(t) ~ t^{8/3} in all dimensions d\geq 1

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

Clinical and hygienic assessment of bone mineral density in population of ecologically contrasting territories.

Disorder of the relationship between biotic and abiotic elements against the background of anthropogenic stress on the human body affects the course of bone remodeling. It is bone tissue in the human body that has the greatest cumulative properties with respect to many xenobiotics, lead in particular. The accumulation of lead in the bone leads to the replacement of calcium ions by ions of the abiotic element and causes further changes in the bone structure: inhibition of growth processes, decreased density, the development of osteopenia and osteoporosis. In the article, a comparative hygienic analysis of bone mineral density levels (according to T-score) in industrial (n=68) and control (n=70) areas was conducted. The T-score, calculated at the LI-LIV level obtained by the method of dual-energy X-ray absorptiometry was used and was evaluated according to the recommendations of the WHO. The formation of a homogeneous sample of persons for the study was conducted according to the place of residence, age, sex, absence of diseases and regular intake of drugs leading to a decrease in bone mass. Summarizing the results, it should be noted that the population of Dniprо city has a more negative and significant decrease in the bone mineral density (according to the T-score) compared to the same values of the control areas – 2.15-4.6 times and Ukraine's – 1.39-4.21 times. According to WHO recommendations, T-score indices for residents of industrial territory indicate to the presence of osteopenia, while among residents of the control area, the norm for this indicator is noted. Consequently, there is an effect of man-made including lead, pollution of the environment on the level of bone mineral density in the industrial city this contributes to the development of osteoporotic changes in the population

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

Mass for the graviton

Can we give the graviton a mass? Does it even make sense to speak of a massive graviton? In this essay I shall answer these questions in the affirmative. I shall outline an alternative to Einstein Gravity that satisfies the Equivalence Principle and automatically passes all classical weak-field tests (GM/r approx 10^{-6}). It also passes medium-field tests (GM/r approx 1/5), but exhibits radically different strong-field behaviour (GM/r approx 1). Black holes in the usual sense do not exist in this theory, and large-scale cosmology is divorced from the distribution of matter. To do all this we have to sacrifice something: the theory exhibits {*prior geometry*}, and depends on a non-dynamical background metric.Comment: 12 pages, plain LaTeX. Major revisions: (1) Inconsistency in equations of motion fixed. (2) More discussion of the problems associated with quantization. (3) Many more references adde