386 research outputs found
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
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
Analysis of patterns formed by two-component diffusion limited aggregation
We consider diffusion limited aggregation of particles of two different
kinds. It is assumed that a particle of one kind may adhere only to another
particle of the same kind. The particles aggregate on a linear substrate which
consists of periodically or randomly placed particles of different kinds. We
analyze the influence of initial patterns on the structure of growing clusters.
It is shown that at small distances from the substrate, the cluster structures
repeat initial patterns. However, starting from a critical distance the initial
periodicity is abruptly lost, and the particle distribution tends to a random
one. An approach describing the evolution of the number of branches is
proposed. Our calculations show that the initial patter can be detected only at
the distance which is not larger than approximately one and a half of the
characteristic pattern size.Comment: Accepted for publication in Physical Review
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
The impact of obesity on the structure of osteoarthrosis of large joints of the lower limb.
The prevalence of osteoarthrosis (OA) among adults over 40 years is taking one of the leading places in the common structure of joint pathology. Obesity – is of the comorbidities associated with OA, one of the risk factors of development and progression of OA. The aim of this study was to evaluate the influence of obesity on the structure of knee and hip OA on the stage of total joint replacement, depending on the patient`s gender, age and degree of obesity. The study involved 170 inpatient case histories of patients with OA undergoing treatment in the department of large joints replacement (64 men and 106 women): 95 patients with OA of hip joint and 75 – with OA of knee joint, among whom there were 110 patients with obesity and 60 – without it. The middle age of the patients was by 63,8±7,69 years. High prevalence of obesity among patients with OA of knee and hip joints was found, with significant higher number of obese patients with OA of knee joint and among female patients. It has been demonstrated a significant increase in the frequency of total knee joint replacement associated with the increase of body mass index among patients with OA of knee joint. The presence of obesity was associated with earlier terms of the total joint replacement performing, especially among male patients
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