The dependence of the exciton-light coupling on the size of a quantum well in an external electric field is theoretically analyzed. It is shown that in a sufficiently strong field, an increase in the ...width of the well leads to weakening of the exciton-light coupling in comparison with narrower wells. Numerical calculations of the longitudinal-transverse exciton splitting are performed for wide ranges of the electric field strength and quantum well width. The analysis of the obtained data allowed us to derive expressions describing the dependences of the exciton-light coupling on both the magnitude of the applied electric field and the well width.
A fast and rigorous method is developed for the electrodynamic analysis of an infinite cylindrical lens made of an artificial material, which is an array of hollow conducting cylinders of finite ...length and finite wall thickness, identically oriented along the lens axis. It is shown that the method makes it possible to calculate the characteristics of lenses consisting of multiple elements using a personal computer. The focusing properties of the lens are studied. The method is an alternative to and a technique to verify the approach based on the analysis of a lens made of a homogenized material with a refractive index of an infinite 3D photonic crystal.
A decrease in the longitudinal-transverse exciton splitting in a wide GaAs/AlGaAs quantum well (QW) in a homogeneous electric field has been theoretically considered. The dependences of the splitting ...on the applied field have been determined. The exciton reflection spectra of the wide QW have been calculated for the case where the field is oriented across the QW layer. The amplitude of exciton-related spectral oscillations is shown to decrease due to a decrease of the photo-excitonic interaction.
The article is devoted to the assessment of the conceptual framework and results of the implementation of the State Program of assistance to voluntary resettlement to the Russian Federation of ...compatriots living abroad in the context of international practice. Programs aimed at returning compatriots are practiced by a number of states wishing to attract ethnically and culturally related migrants or restore historical justice in relation to certain ethno-confessional groups. Typically, they exist along with other immigration programs, providing repatriates with almost unfettered admission to the country. Since 2006, the only program in this field in Russia is the State Program of assistance to voluntary resettlement of compatriots. The originally formulated principles place it in a special position when compared with other repatriation programs. Based on the evaluation of the experience of the Russian program and international experience in the establishment and application of ethnic repatriation programs, it was concluded that in some cases the additional requirements for compatriots are hardly compatible with the main humanitarian task of a repatriation program, which affects its final effectiveness.
Background. In laparoscopic cholecystectomy (LCE), general anesthesia has its own characteristics due to the creation of pneumoperitoneum, changes in body position and adsorption of insufflated gas, ...which causes the occurrence of perioperative complications and requires improvement of anesthesiology programs.
Objective: to determine the efficacy and safety of combined low opioid anesthesia based on dexmedetomidine in complex anesthesia in patients undergoing laparoscopic surgery for acute cholecystitis.
Materials and methods. In total, the study included 163 patients undergoing LCE under general anesthesia. All patients were divided into 3 groups according to the anesthetic care scheme. In Group 1 (n=56), low-opioid anesthesia (dexmedetomidine, lidocaine, fentanyl 1–2 μg/kg/h) and artificial ventilation were performed; Group 2 (n=52): propofol with fentanyl (4–6 μg/kg/h) and artificial ventilation. In Group 3 (n=55): anesthesia with sevoflurane in combination with fentanyl and artificial ventilation.
Results. Hyperdynamic reactions were observed in Group 2 and Group 3 at the beginning of the operation: heart rates and BP values after induction, with intubation in the 3rd, 5th and 7th minute of pneumoperitoneum, were slightly higher in Group 2 and 3 than in Group 1. However, moderate bradycardia was observed in Group 1 more often – in 5 patients (8.92%) than in patients in Group 2 and Group 3 – 2 cases (3.84%) and 2 cases (3.64%), respectively. The total number of injected analgesics during LCE was: in Group 1 – 141.52±23.64 μg, in Group 2 – 426.92±39.41 μg, in Group 3 – 354.75±28.63 μg (p <0.01). Only one patient in Group 1 required ondansetron for the treatment of PONV compared to 5 and 4 in Group 2 and Group 3, respectively (p <0.05). None of the patients in all groups reported “feeling” intraoperative events or “awakening during surgery”.
Conclusions. The use of dexmedetomidine with lidocaine infusion three times reduced the use of opioids in the intraoperative period and to refuse their use in the postoperative period. With the use of low-opioid anesthesia in the postoperative period, the frequency of hypertensive reactions and tachycardia did not increase, but in the postoperative period, these p
The Convective Transport of Active Species in the Tropics (CONTRAST) experiment was conducted from Guam (13.5°N, 144.8°E) during January–February 2014. Using the NSF/NCAR Gulfstream V research ...aircraft, the experiment investigated the photochemical environment over the tropical western Pacific (TWP) warm pool, a region of massive deep convection and the major pathway for air to enter the stratosphere during Northern Hemisphere (NH) winter. The new observations provide a wealth of information for quantifying the influence of convection on the vertical distributions of active species. The airborne in situ measurements up to 15-km altitude fill a significant gap by characterizing the abundance and altitude variation of a wide suite of trace gases. These measurements, together with observations of dynamical and microphysical parameters, provide significant new data for constraining and evaluating global chemistry–climate models. Measurements include precursor and product gas species of reactive halogen compounds that impact ozone in the upper troposphere/lower stratosphere. High-accuracy, in situ measurements of ozone obtained during CONTRAST quantify ozone concentration profiles in the upper troposphere, where previous observations from balloonborne ozonesondes were often near or below the limit of detection. CONTRAST was one of the three coordinated experiments to observe the TWP during January–February 2014. Together, CONTRAST, Airborne Tropical Tropopause Experiment (ATTREX), and Coordinated Airborne Studies in the Tropics (CAST), using complementary capabilities of the three aircraft platforms as well as ground-based instrumentation, provide a comprehensive quantification of the regional distribution and vertical structure of natural and pollutant trace gases in the TWP during NH winter, from the oceanic boundary to the lower stratosphere.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Аn analytical solution for a spherically stratified medium is constructed on the strength of an earlier obtained exact solution of Kompaneets equation for the shock front in a planar stratified ...medium with the density changing as the hyperbolic tangent. The solution obtained allows to build entirely the shock front and explore its evolution for different values of independent parameters (density gradient, explosion point position, scale of inhomogeneity) which varying can permit simulation of real conditions while obtaining information on medium properties and supernova remnant evolution.
Excitonic waves propagating in thick GaAs/AlGaAs quantum wells form an interference pattern, which is observed as oscillations in the reflectance spectra. Oscillations in the spectra of wide GaAs ...quantum wells should reveal a non-trivial behavior as a function of the external uniform electric field as it is found in the theory developed in the present work. The oscillations are suppressed as the electric field increases and then reappear again with an opposite phase at the further rise of the field.
Modern climate change and variability of the natural environment have a significant impact on the quality of life and health of the population, as well as on the development of the recreational and ...touristic industry in resort cities. Based on the long-term observations (1993–2023), the changes in the following climatic characteristics have been analyzed: surface air temperature, total precipitation, and current microbioclimatic parameters of the resort city of Kislovodsk. It has been found for the past 30 years that the average annual temperature in Kislovodsk according to the scale of balneological significance can be identified as favorable, and the average annual minimum and maximum temperatures can be characterized as the most favorable. The statistical parameters of the analyzed characteristics and their extremes are presented. The microbioclimatic potential of the central part of the city is characterized by an increased level of natural air ionization and high purity of the surface atmosphere in the areas that do not experience high anthropogenic load.
The animal model of intestinal dysbiosis induced by antibiotics was created. Dysbiotic condition was confirmed by the changes in titre of the indigenous microbiota (excessive growth of opportunistic ...microorganisms and reduced number of lactobacilli, bifidobacteria and enterococci) and the appearance of dyspeptic symptoms. Consumption of the fermented milk product with probiotic strain Enterococcus faecium L5 led to the rapid disappearance of dysbiosis symptoms, normalisation of the microbiota, increase in expression of IL-10 and decrease in IL-8 expression.
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