A systematic study on the Weibel instability induced filamentation of a relativistic electron beam is made by including the effects of collisions and temperature. The stabilization and ...de-stabilization of the beam filamentation due to beam temperature and plasma collisions, respectively, is explored through an analytical model and PIC simulations. The de-stabilization of the beam filamentation is attributed to the collision driven negative energy wave generation in the beam plasma system.
We measure, simulate, and analyze the optical transmission through arrays of Ag nanorod pairs and U-shaped nanostructures as a function of polarization and angle of incidence. The bianisotropic ...nature of the metamaterials is exhibited in data and in simulations, and we argue that the electric field rather than the magnetic field excites the low frequency "magnetic" mode. We also observe spatial dispersion in the form of frequency shifts as a function of incident angle which we attribute to coupling effects between neighboring structures. A simple model based upon coupled electromagnetic dipoles is found to provide a qualitative description for the main features observed in the spectra.
Objective - analysis of the epizootic-epidemiological situation on natural-focal infections in the resort city of Sochi. Materials and methods. We used the reports on and results of annual ...epizootiological monitoring of the territory of Sochi, presented by the Rospotrebnadzor Administration in the Krasnodar Territory, Center of Hygiene and Epidemiology in the Krasnodar Territory, Black Sea Plague Control Station, Sochi Anti-Plague Department of the Black Sea Plague Control Station, Stavropol Research Anti-Plague Institute. Results and discussion. The paper provides the analysis of the incidence among population, the results of epizootiological monitoring and molecular-genetic studies of isolates collected in the territory of the resort city of Sochi during 2014-2018. The most significant natural-focal infections in this region are: hemorrhagic fever with renal syndrome, Lyme disease, intestinal yersiniosis, leptospirosis. It was established that the natural foci of the infections studied in the territory of the resort city of Sochi are combined ones, which increases their epidemic importance and imposes requirements for a more in-depth survey of the territories. Thus, the current epizootiological-epidemiological situation on natural-focal infections in the region of the resort city of Sochi is characterized by the preservation of the activity of natural foci and indicates the need for their continuous monitoring, as well as implementation of a set of regulated preventive measures.
We theoretically and experimentally study electromagnetic properties of a novel mid-infrared metamaterial: optically thin silicon carbide (SiC) membrane perforated by an array of sub-wavelength ...holes. Giant absorption and transmission is found using Fourier transformed infrared (FTIR) microscopy and explained by introducing a frequency-dependent effective permittivity εeff(ω) of the perforated film. The value of εeff(ω) is determined by the excitation of two distinct types of hole resonances: delocalized slow surface polaritons (SSPs) whose frequencies are largely determined by the array period, and a localized surface polariton (LSP) corresponding to the resonance of an isolated hole. Only SSPs are shown to modify εeff(ω) strongly enough to cause giant transmission and absorption. Because of the sub-wavelength period of the hole array, anomalous optical properties can be directly traced to surface polaritons, and their interpretation is not obscured by diffractive effects. Giant absorbance of this metamaterial can be utilized in designing highly efficient thermal radiation sources.
The phenomena of slow and super-luminal propagation of electromagnetic waves are considered in the context of a magnetized plasma with undulator induced transparency (UIT). Without the magnetic ...undulator, the plasma is opaque to the right-hand circularly polarized radiation at the electron cyclotron frequency. Addition of a helical undulator results in the dramatic slowing down of wave propagation. Super-luminal propagation occurs due to the strong coupling between the right- and left-hand circularly polarized waves. We demonstrate that, depending on the detected wave polarization, super-luminal and slow radiation can be observed at the same frequency. Moreover, the super-luminal signal can be controlled by the intensity of the incident signal.
Two different approaches to the synthesis of 1-unsubstituted 5-cinnamoyl-3,4-dihydropyrimidine-2(1H)-ones have been developed. The first includes N(1)-protection of the starting ...5-acetyl-3,4-dihydropyrimidine-2(1H)-one, further Claisen-Schmidt reaction, and cleavage of the protecting group. The second approach consists of one-pot condensation of urea, aldehyde, and cinnamoylacetone as dicarbonyl component. The 5-cinnamoylderivative synthesis starting from 5-acetyl-1,3-dialkyl-3,4-dihydropyrimidine-2(1H)-ones is also shown.
Objective of the study was to investigate the current borders of the invasive species Ae. aegypti and Ae. albopictus distribution in the south of the Krasnodar Region and climatic factors limiting ...their expansion. Material and methods. Mosquito larvae, pupa and imago were collected in 21 inhabited localities in August–September, 2017, using conventional entomological methods, and identified through standard morphological keys. Climatic data found on the website pogoda. ru were analyzed using SPSS program. Results and conclusions. Ae. albopictus is widely spread along the Black Sea coast, from Adler to Novorossiysk (Ozereyevka), as well as on the north slopes of Caucasus up to Maikop. Additional investigations are required to specify the northern border of species distribution and to evidence the existence of established populations here. Ae. aegypti were not found in the south of the Krasnodar Region. The obtained data suggest a possibility of much wider spreading of dengue, Chikungunya and Zika fevers in case of pathogen importation to the south of Krasnodar Region, than was assumed earlier.
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