444 research outputs found
A review of species of the genus Mocyta (Coleoptera, Staphylinidae) in Ukraine
A review of the genus Mocyta Mulsant & Rey, 1874, which is represented in Ukraine; a description of the main morphological features and diagnostic features is made, data on ecological features, seasonal activity of adults, the distribution of representatives of the genus in Ukraine and the world and the keys to identify the species are presented. The information on the distribution of species of the genus Mocyta in the territory of Ukraine has been clarified and significantly supplemented by new findings. The results can be used to address a number of theoretical issues of faunistics, zoogeography, and ecology, as well as in compiling the inventory of the fauna of the Ukrainian Carpathians, for comparative faunal research, in the analysis of species distribution, in biogeographic constructions, studies of faunogenesis, ecological monitoring and prediction of consequences of the influence of human activities on natural ecosystems of the region. The genus Mocyta is a widespread genus, which in terms of the combination of morphological and biological features belongs to the tribe Athetini Casey, 1910 of the subfamily Aleocharinae Fleming, 1821 of the family Staphylinidae Latreille, 1802. There are 26 known species in the fauna of Palearctic, 5 of which (Mocyta clientula, M. fungi fungi, M. fussi, M. orbata, M. orphana) are represented in the fauna of Ukraine. However, it is likely that there are two more species (M. amplicollis and M. negligens), identified for the surrounding areas, for which characteristics and comparative diagnoses have also been provided. This paper is a continuation of the initiated series of reviews of genera and species of the tribe Athetini of the fauna of Ukraine. Taking into account the wide geographical distribution and significant individual variability in size, colour and shape of the spermatheca of representatives of the genus, the identification of the latter presents some significant difficulties
Scattering of backward spin waves in a one-dimensional magnonic crystal
Scattering of backward volume magnetostatic spin waves from a one-dimensional
magnonic crystal, realized by a grating of shallow grooves etched into the
surface of an yttrium-iron garnet film, was experimentally studied. Rejection
frequency bands were clearly observed. The rejection efficiency and the
frequency width of the rejection bands increase with increasing groove depth. A
theoretical model based on the analogy of a spin-wave film-waveguide with a
microwave transmission line was used to interpret the obtained experimental
results.Comment: 4 pages, 3 figure
Dynamic correlations in an ordered c(22) lattice gas
We obtain the dynamic correlation function of two-dimensional lattice gas
with nearest-neighbor repulsion in ordered c(22) phase
(antiferromagnetic ordering) under the condition of low concentration of
structural defects. It is shown that displacements of defects of the ordered
state are responsible for the particle number fluctuations in the probe area.
The corresponding set of kinetic equations is derived and solved in linear
approximation on the defect concentration. Three types of strongly correlated
complex jumps are considered and their contribution to fluctuations is
analysed. These are jumps of excess particles, vacancies and flip-flop jumps.
The kinetic approach is more general than the one based on diffusion-like
equations used in our previous papers. Thus, it becomes possible to adequately
describe correlations of fluctuations at small times, where our previous theory
fails to give correct results. Our new analytical results for fluctuations of
particle number in the probe area agree well with those obtained by Monte Carlo
simulations.Comment: 10 pages, 7 figure
Age-related relationship between the development of hyperplastic processes and VEGF expression in endometrial cells
The existence of a clear tendency to increase the prevalence of hormone-dependent diseases and endometrial cancer against the background of increasing the frequency of their occurrence and rejuvenation of the age of manifestation leads to the search for new possible markers of diagnosis and prognosis of the development of pathological process. Angiogenesis is one of the forms that lead to the formation of new blood vessels, with an increased metabolic need for perfusion of existing vessels. The vascular endothelial growth factor family (VEGF) is a protein that is the major inducer of angiogenesis. The objective: To study the expression of VEGF in endometrial cells in proliferative, hyperplastic, atrophic states at women’s different ages. Materials and methods. A retrospective analysis of medical records of the pathohistological bureau for the period 2014-2016 was conducted. 2196 pathomorphological findings of endometrial tissue specimens have been examined. Estimation of VEGF expression was performed in 417 endometrial specimens, in the cohorts of the study: in the reproductive, perimenopausal, postmenopausal periods, respectively, in groups with physiological endometrial proliferation phase, hyperplastic, atypical, atrophic endometrium. The results were statistically processed. Results and discussion. Analyzing the data presented, higher VEGF expression was detected in atypical hyperplasia in all age categories, but it was likely that higher rates were established in the postmenopausal period, with atypical endometrial hyperplasia, suggesting physicians' alertness to the process in this category. Probably low were indexes found at atrophic endometrium in this age category, which confirms the endometrial preservation of its growth factors, and in the presence of processes that stimulate the proliferation of the organ, they can trigger at the molecular-genetic level, neoplastic mechanisms. The data of the retrospective analysis confirm the growth of atypical form of hyperplastic processes and their maximum detection in the age categories 41 - 45 and 46 - 50 years old, and the beginning of detection of endometrial malignancy from the age of 46 - 50 years old, with a gradual increase with age. Conclusions. Expression of VEGF level in endometrial tissue cells as an inducer of angiogenesis can be a promising marker for the diagnosis of the risk of proliferative conditions and their prognosis, especially in relation to other markers characterizing immunohistochemical and molecular genetic cellular parameters
Influence of Phase Diffuser Dynamics on Scintillations of Laser Radiation in Earth Atmosphere: Long-Distance Propagation
The effect of a random phase diffuser on fluctuations of laser light
(scintillations) is studied. Not only spatial but also temporal phase
variations introduced by the phase diffuser are analyzed. The explicit
dependence of the scintillation index on finite-time phase variations is
obtained for long propagation paths. It is shown that for large amplitudes of
phase fluctuations, a finite-time effect decreases the ability of phase
diffuser to suppress the scintillations.Comment: 15 pages, 4 figure
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