An ab-initio study of the electron-phonon coupling within a Cr(001)-surface

It is experimentally well established that the Cr(001)-surface exhibits a sharp resonance around the Fermi level. However, there is no consensus about its physical origin. It is proposed to be either due to a single particle dz2 surface state renormalised by electron-phonon coupling or the orbital Kondo effect involving the degenerate dxz/dyz states. In this work we examine the electron-phonon coupling of the Cr(001)-surface by means of ab-initio calculations in the form of density functional perturbation theory. More precisely, the electron-phonon mass-enhancement factor of the surface layer is investigated for the 3d states. For the majority and minority spin dz2 surface states we find values of 0.19 and 0.16. We show that these calculated electron-phonon mass-enhancement factors are not in agreement with the experimental data even if we use realistic values for the temperature range and surface Debye frequency for the fit of the experimental data. More precisely, then experimentally an electron-phonon mass-enhancement factor of 0.70~0.10 is obtained, which is not in agreement with our calculated values of 0.19 and 0.16. Therefore, we conclude that the experimentally observed resonance at the Cr(001)-surface is not due to polaronic effects, but due to electron-electron correlation effects

Strong-field approximation for Coulomb explosion of H_2^+ by short intense laser pulses

We present a simple quantum mechanical model to describe Coulomb explosion of H$_2^+$ by short, intense, infrared laser pulses. The model is based on the length gauge version of the molecular strong-field approximation and is valid for pulses shorter than 50 fs where the process of dissociation prior to ionization is negligible. The results are compared with recent experimental results for the proton energy spectrum [I. Ben-Itzhak et al., Phys. Rev. Lett. 95, 073002 (2005), B. D. Esry et al., Phys. Rev. Lett. 97, 013003 (2006)]. The predictions of the model reproduce the profile of the spectrum although the peak energy is slightly lower than the observations. For comparison, we also present results obtained by two different tunneling models for this process.Comment: 8 pages, 4 figure

Interconnection between aggression and protection factors of gastric juice and oral liquid of the patients with precancerous changes of gastric mucosa

This article is about learning of the aggression factors and the gastric juice and oral liquid protection of the patients with precancerous changes in the mucous gastric membrane of stomach. 32 middle-aged people were researched, who were at the inpatient treatment at the SI “Institute of Gastroenterology of NAMS of Ukraine”: 6 of them were with the atrophic changes of mucous membrane of stomach with different rate of severity (the I group), 12 people were with the intestinal metaplasia in the antrum (the II group), 14 patients were with intestinal metaplasia in the body and in the antrum of mucous membrane of stomach (the III group). The diagnosis was established after meticulous endoscopic and histological researches of biopsy material of mucous membrane of stomach. During the esophagogastroscopic research the gastric juice was being collected. It was determined its pH, pepsin, glycoprotein, sialic acids, fucose and hexosamines concentration. Also there were conducted the investigations of oral liquid, where the content of glycoprotein, sialic acid, fucose and hexosamines was determined. In the gastric juice of patients of the II and III groups, the content of sialic acids was increased, in the III – the acid secretion increased the hexosamines, with anacid – of fucose and it was decreased the amount of pepsin. In the oral liquid, the content of sialic acids in all researching groups was increased, fucose - only in the I group, hexosamines and glycoproteins - only in the III group. The further complex study of functional-morphological changes of gastric secretion and salivary glands activity will allow to assess the condition of reserve capabilities of the protection factors of the mucous membrane of the stomach and to determine the risk groups of patients with the precancerous condition

Atmospheric Gravity Perturbations Measured by Ground-Based Interferometer with Suspended Mirrors

A possibility of geophysical measurements using the large scale laser interferometrical gravitational wave antenna is discussed. An interferometer with suspended mirrors can be used as a gradiometer measuring variations of an angle between gravity force vectors acting on the spatially separated suspensions. We analyze restrictions imposed by the atmospheric noises on feasibility of such measurements. Two models of the atmosphere are invoked: a quiet atmosphere with a hydrostatic coupling of pressure and density and a dynamic model of moving region of the density anomaly (cyclone). Both models lead to similar conclusions up to numerical factors. Besides the hydrostatic approximation, we use a model of turbulent atmosphere with the pressure fluctuation spectrum f^{-7/3} to explore the Newtonian noise in a higher frequency domain (up to 10 Hz) predicting the gravitational noise background for modern gravitational wave detectors. Our estimates show that this could pose a serious problem for realization of such projects. Finally, angular fluctuations of spatially separated pendula are investigated via computer simulation for some realistic atmospheric data giving the level estimate 10^{-11} rad/sqrt(Hz) at frequency 10^{-4} Hz. This looks promising for the possibility of the measurement of weak gravity effects such as Earth inner core oscillations.Comment: 13 pages, 4 pigures, LaTeX. To be published in Classical and Quantum Gravit

Experimental research of technological scheme of membran wastewater purification

Останнім часом мембранні процеси розділення рідких сумішей показали свою високу ефективність у різних галузях промисловості. При цьому застосування мембранної технології дозволяє не тільки вирішувати технологічні завдання, а й зменшувати техногенне навантаження на навколишнє середовище. В даній статті представлені експериментальні дослідження технологічних параметрів та режимів проведення процесу очищення, аналіз яких дозволяє визначити ефективні схеми очистки стічних вод. Авторами запропоновано для більш ретельного очищення води використовувати поєднання первапорації та сорбції з використанням мембранних елементів.Object. Experimental studies of technological parameters of process waste water purification and identification of the most effective technological scheme selection of organic pollution from wastewater. Design, methodology, approach. For the study of pervaporation process was used experimental unit that allows varying removal methods vapors of organic substances, hydrodynamic and temperature regimes. In the experimental unit had been dune the series of experiments of the temperature effect to the purification degree of wastewater from the organic impurities. Then had been dune series of experiments for determined the concentration of organic pollutants in a model liquid that after pervaporation was arrived to the "sorption" apparatus for the addition purification. Conclusions. It was found that purification process intensifies with increase the temperature of the model liquid applying to separation. Also the combination of pervaporation at different temperature regimes with sorption membrane elements was using, which gives greatly improving efficiency of purification of the model liquid of organic component. Research novelty / importance. Had been developed hybrid scheme of water purification which is based on a combination pervaporation with sorption membrane elements. The research has shown the feasibility of using of the hybrid schemes for wastewater treatment.В последнее время мембранные процессы разделения смесей показали свою высокую эффективность в различных отраслях промышленности. При этом применение мембранной технологии позволяет не только решать технологические задачи, но и уменьшать техногенную нагрузку на окружающую среду. В данной статье представлены экспериментальные исследования технологических параметров и режимов проведения процесса очистки, анализ которых позволяет определить эффективные схемы очистки сточных вод. Авторами предложен для более тщательной очистки воды использовать сочетание первапорации и сорбции с использованием мембранных элементов

Very high frequency gravitational wave background in the universe

Astrophysical sources of high frequency gravitational radiation are considered in association with a new interest to very sensitive HFGW receivers required for the laboratory GW Hertz experiment. A special attention is paid to the phenomenon of primordial black holes evaporation. They act like black body to all kinds of radiation, including gravitons, and, therefore, emit an equilibrium spectrum of gravitons during its evaporation. Limit on the density of high frequency gravitons in the Universe is obtained, and possibilities of their detection are briefly discussed.Comment: 14 page

Прогнозирование степени тяжести острого панкреатита с использованием ультразвуковых маркеров и клинических шкал

Abstract For the timely determination of the tactics of treatment of acute pancreatitis, it is necessary to predict the severity when the patient enters the hospital.Aim of the study To assess the possibility of predicting the severity of acute pancreatitis using ultrasound markers, clinical scales.Material and methods A retrospective analysis of the diagnostic results of 84 patients who were hospitalized for acute pancreatitis was carried out. The results of clinical-laboratory and morphological diagnostic methods obtained upon admission of a patient to a hospital in patients with varying degrees of severity of ap were analyzed. Clinical and laboratory data were analyzed using prognostic scales — marshall, ranson, sofa, bisap. The analysis of morphological changes in the pancreas during ultrasound and computed tomography was performed using the balthazar classification.Results The sensitivity of clinical scales for determining the severity of ap was 67% on the sofa scale, 87.5% on the bisap scale, and 100% on the ranson and marshall scales. All patients (22) who had signs corresponding to the balthazar stage d and e upon ultrasound examination subsequently had a moderate and severe course of the disease.Conclusion The use of ultrasonic markers of acute pancreatitis in conjunction with the data of clinical and laboratory scales makes it possible to predict the severity of acute pancreatitis.АКТУАЛЬНОСТЬ Для своевременного определения тактики лечения острого панкреатита (ОП) необходимо прогнозирование степени тяжести при поступлении пациента в стационар.ЦЕЛЬ ИССЛЕДОВАНИЯ Оценить возможность прогнозирования степени тяжести ОП с помощью ультразвуковых маркеров, клинических шкал.МАТЕРИАЛ И МЕТОДЫ Проведен ретроспективный анализ результатов диагностики 84 больных, находившихся на стационарном лечении по поводу ОП. Проанализированы результаты клинико-лабораторных и морфологических методов диагностики, полученных при поступлении в стационар у пациентов с различной степенью тяжести ОП. Клинико-лабораторные данные проанализированы с использованием прогностических шкал Marshall, Ranson, SOFA, BISAP. Анализ морфологических изменений поджелудочной железы при ультразвуковом исследовании (УЗИ) и компьютерной томографии проводили с помощью классификации Balthazar.РЕЗУЛЬТАТЫ Чувствительность клинических шкал для определения степени тяжести ОП составила 67% по шкале SOFA, 87,5% — по шкале BISAP, 100% по шкалам Ranson и Marshall. У всех пациентов (n=22), у которых при УЗИ выявлялись признаки, соответствующие шкале Balthazar стадии D и Е, впослед­ствии наблюдалось среднетяжелое и тяжелое течение заболевания.ВЫВОД Использование ультразвуковых маркеров острого панкреатита в совокупности с данными клинико-лабораторных шкал позволяет прогнозировать степень тяжести острого панкреатита