Ground-based acoustic parametric generator impact on the atmosphere and ionosphere in an active experiment

We develop theoretical basics of active experiments with two beams of acoustic waves, radiated by a ground-based sound generator. These beams are transformed into atmospheric acoustic gravity waves (AGWs), which have parameters that enable them to penetrate to the altitudes of the ionospheric E and F regions where they influence the electron concentration of the ionosphere. Acoustic waves are generated by the ground-based parametric sound generator (PSG) at the two close frequencies. The main idea of the experiment is to design the output parameters of the PSG to build a cascade scheme of nonlinear wave frequency downshift transformations to provide the necessary conditions for their vertical propagation and to enable penetration to ionospheric altitudes. The PSG generates sound waves (SWs) with frequencies f1 = 600 and f2 = 625 Hz and large amplitudes (100-420ms-1). Each of these waves is modulated with the frequency of 0.016 Hz. The novelty of the proposed analytical-numerical model is due to simultaneous accounting for nonlinearity, diffraction, losses, and dispersion and inclusion of the two-stage transformation (1) of the initial acoustic waves to the acoustic wave with the difference frequency Δf = f2 - f1 in the altitude ranges 0-0.1 km, in the strongly nonlinear regime, and (2) of the acoustic wave with the difference frequency to atmospheric acoustic gravity waves with the modulational frequency in the altitude ranges 0.1-20 km, which then reach the altitudes of the ionospheric E and F regions, in a practically linear regime. AGWs, nonlinearly transformed from the sound waves, launched by the two-frequency ground-based sound generator can increase the transparency of the ionosphere for the electromagnetic waves in HF (MHz) and VLF (kHz) ranges. The developed theoretical model can be used for interpreting an active experiment that includes the PSG impact on the atmosphere-ionosphere system, measurements of electromagnetic and acoustic fields, study of the variations in ionospheric transparency for the radio emissions from galactic radio sources, optical measurements, and the impact on atmospheric aerosols. The proposed approach can be useful for better understanding the mechanism of the acoustic channel of seismo-ionospheric coupling

Model of the propagation of very low-frequency beams in the Earth–ionosphere waveguide: principles of the tensor impedance method in multi-layered gyrotropic waveguides

The modeling of very low-frequency (VLF) electromagnetic (EM) beam propagation in the Earth–ionosphere waveguide (WGEI) is considered. A new tensor impedance method for modeling the propagation of electromagnetic beams in a multi-layered and inhomogeneous waveguide is presented. The waveguide is assumed to possess the gyrotropy and inhomogeneity with a thick cover layer placed above the waveguide. The influence of geomagnetic field inclination and carrier beam frequency on the characteristics of the polarization transformation in the Earth–ionosphere waveguide is determined. The new method for modeling the propagation of electromagnetic beams allows us to study the (i) propagation of the very low-frequency modes in the Earth–ionosphere waveguide and, in perspective, their excitation by the typical Earth–ionosphere waveguide sources, such as radio wave transmitters and lightning discharges, and (ii) leakage of Earth–ionosphere waveguide waves into the upper ionosphere and magnetosphere. The proposed approach can be applied to the variety of problems related to the analysis of the propagation of electromagnetic waves in layered gyrotropic and anisotropic active media in a wide frequency range, e.g., from the Earth–ionosphere waveguide to the optical waveband, for artificial signal propagation such as metamaterial microwave or optical waveguides

Enhanced inverse bremsstrahlung heating rates in a strong laser field

Test particle studies of electron scattering on ions, in an oscillatory electromagnetic field have shown that standard theoretical assumptions of small angle collisions and phase independent orbits are incorrect for electron trajectories with drift velocities smaller than quiver velocity amplitude. This leads to significant enhancement of the electron energy gain and the inverse bremsstrahlung heating rate in strong laser fields. Nonlinear processes such as Coulomb focusing and correlated collisions of electrons being brought back to the same ion by the oscillatory field are responsible for large angle, head-on scattering processes. The statistical importance of these trajectories has been examined for mono-energetic beam-like, Maxwellian and highly anisotropic electron distribution functions. A new scaling of the inverse bremsstrahlung heating rate with drift velocity and laser intensity is discussed.Comment: 12 pages, 12 figure

Transvaginal mesh-reconstruction of anterior apical prolapse: a selective implant choosing approach

Introduction. Transvaginal mesh-reconstruction of urogenital prolapse remains a controversial trend in modern urogynecology. We have seen growth in transvaginal mesh surgery since 2004, followed by a sharp decline after 2011 due to FDA restrictions related to imperfections in previously available prostheses and implantation techniques. Improving the efficacy and minimizing complications of transvaginal mesh-surgery is at the forefront of research in the field of modern urogynecology.Purpose of the study. To optimize the indications for transvaginal mesh-reconstruction of anterior apical prolapse.Materials and methods. The study enrolled 375 patients with anterior apical prolapse. The grade of prolapse was assessed using POP-Q. In patients with endopelvic pelvic fascia insufficiency, severe cystocele (Aa ≥ +1) and hysteroptosis grade II – IV, the correction was carried out using the six-arm OPUR® («ABISS», Saint-Étienne, France). lightweight polypropylene monofilament implant (n = 290). When the cystocele was not prominent (Aa ≤ -1) and grade III – IV hysteroptosis, posterior sacrospinal hysteropexy was preferred with the CYRENE® («ABISS», Saint-Étienne, France) tape (n = 85). In 35 patients, the operation was combined with anterior colporrhaphy. In 5 patients, a simultaneous conization/amputation of the cervix was performed. The examination was performed 1 month after surgery and then annually. Prolapse ≥ grade II was as recurrent. The follow-up period of 67 patients was more than 4 years.Results. After OPUR® prosthesis implantation, recurrent hysteroptosis was detected in 6 women with cervical hypertrophy / elongation within a period of 1 mo to 3.5 yr and cystocele in 4 patients. The efficacy was 96%. In 9 patients, an postoperative ischuria was found associated with extensive dissection and hypotension of the bladder wall due to chronic urinary retention in severe cystocele. Urination improved in 88% of cases. In the remaining cases, long-term mediator and hormone replacement therapy were continued., One recurrent hysteroptosis was observed during the implantation of the CYRENE® prosthesis. No damage to the bladder was observed. Acute urinary retention was detected in 1 case, which resolved after intermittent catheterization. Conclusion. The availability of 2 types of transvaginal prostheses for various degrees and configurations of urogenital prolapses allows a differentiated approach to their choice. Both prostheses suggest reliable «reconstruction-imitation» of the sacroiliac ligament by sacrospinal hysteropexy. If necessary, the operation can be supplemented with anterior colporrhaphy. The prevalence of anterior prolapse with endopelvic fascia insufficiency requires more extensive reconstruction, which can be performed relatively safely and effectively by implantation of a 6-arm OPUR® prosthesis

Chemistry labs made on UNITY 3D

Статья посвящена созданию компьютерного симулятора лабораторных работ по химии. В статье описан процесс создания симулятора: от выбора технологий до программной реализации. Продукт представляет собой интерактивный 3D-симулятор, запускаемый из исполняемого файла Windows (*.exe), включающий: выбор необходимой лабораторной работы (всего доступно 10 штук), набор необходимых элементов для лабораторной работы, выполнение самой работы, подсказки для пользователя и инструкции действий пользователя. Целью создания продукта является освоение и демонстрация новых 3D-технологий, а также помощь в дистанционном обучении (в данном случае, химии).The article is devoted to computer simulators, virtual chemistry labs in particular. The article tells about the process of choosing from different technologies for developing the simulator and about the developing itself. The product is an interactive 3D-simulator, which includes: a choice of a lab needed (10 pcs. available overall), all necessary elements for any lab, the process of doing the lab, tips for the user and user guides. The goal of the product is to demonstrate the new 3D-technologies and the help in the distant education (the subject is chemistry in this case)

Mechanical and Electronic Properties of MoS2_2 Nanoribbons and Their Defects

We present our study on atomic, electronic, magnetic and phonon properties of one dimensional honeycomb structure of molybdenum disulfide (MoS$_2$) using first-principles plane wave method. Calculated phonon frequencies of bare armchair nanoribbon reveal the fourth acoustic branch and indicate the stability. Force constant and in-plane stiffness calculated in the harmonic elastic deformation range signify that the MoS$_2$ nanoribbons are stiff quasi one dimensional structures, but not as strong as graphene and BN nanoribbons. Bare MoS$_2$ armchair nanoribbons are nonmagnetic, direct band gap semiconductors. Bare zigzag MoS$_2$ nanoribbons become half-metallic as a result of the (2x1) reconstruction of edge atoms and are semiconductor for minority spins, but metallic for the majority spins. Their magnetic moments and spin-polarizations at the Fermi level are reduced as a result of the passivation of edge atoms by hydrogen. The functionalization of MoS$_2$ nanoribbons by adatom adsorption and vacancy defect creation are also studied. The nonmagnetic armchair nanoribbons attain net magnetic moment depending on where the foreign atoms are adsorbed and what kind of vacancy defect is created. The magnetization of zigzag nanoribbons due to the edge states is suppressed in the presence of vacancy defects.Comment: 11 pages, 5 figures, first submitted at November 23th, 200

Third party consultation: a method for the study and resolution of conflict

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66597/2/10.1177_002200277201600105.pd

Increased Brain Fatty Acid Uptake in Metabolic Syndrome

OBJECTIVE: To test whether brain fatty acid uptake is enhanced in obese subjects with metabolic syndrome (MS) and whether weight reduction modifies it. RESEARCH DESIGN AND METHODS: We measured brain fatty acid uptake in a group of 23 patients with MS and 7 age-matched healthy control subjects during fasting conditions using positron emission tomography (PET) with [(11)C]-palmitate and [(18)F]fluoro-6-thia-heptadecanoic acid ([(18)F]-FTHA). Sixteen MS subjects were restudied after 6 weeks of very low calorie diet intervention. RESULTS: At baseline, brain global fatty acid uptake derived from [(18)F]-FTHA was 50% higher in patients with MS compared with control subjects. The mean percentage increment was 130% in the white matter, 47% in the gray matter, and uniform across brain regions. In the MS group, the nonoxidized fraction measured using [(11)C]-palmitate was 86% higher. Brain fatty acid uptake measured with [(18)F]-FTHA-PET was associated with age, fasting serum insulin, and homeostasis model assessment (HOMA) index. Both total and nonoxidized fractions of fatty acid uptake were associated with BMI. Rapid weight reduction decreased brain fatty acid uptake by 17%. CONCLUSIONS: To our knowledge, this is the first study on humans to observe enhanced brain fatty acid uptake in patients with MS. Both fatty acid uptake and accumulation appear to be increased in MS patients and reversed by weight reduction