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For the first time in Armenia, gamma activation analysis of geological samples of obsidian was carried out using beams of bremsstrahlung photons at the linear electron accelerator of the A. Alikhanyan National Scientific Laboratory (AANL). It is shown that the results of the chemical composition of the obsidian sample are comparable with the results of instrumental neutron activation analysis (INAA) of the same sample, carried out at the Curt-Engelhom-Center for Archaeometry (Mannheim, Germany), after irradiation with neutrons in a specialized nuclear reactor TRIGA at the Institute of Nuclear Chemistry of the Mainz University. It is also shown that gamma activation analysis makes it possible to determine the content of a number of elements for which the use of INAA is impossible or difficult. [ABSTRACT FROM AUTHOR]

Samples made from natural bismuth were exposed in 60 MeV end-point bremsstrahlung beam. In this paper, a simple model for determination the share of two ways of 203Pb formation: by the decay of 203Bi, produced in 209Bi(γ,6n)203Bi reaction and by 209Bi(γ,p 5n)203Pb reaction is described. The method employs the ratio of 203Pb and 203Bi nuclei numbers and activities at the end of the exposure as the input value. This ratio was estimated from gamma spectra measured after irradiation of natural Bi sample. It was found that the rate of production of 203Pb by 209Bi(γ,p 5n)203Pb reaction is about 6% of the 203Bi production rate in the 209Bi(γ,6n)203Bi reaction. Obtained result is compared with TALYS based estimation. [ABSTRACT FROM AUTHOR]

At the linear electron accelerator AANL (YerPhI), at mean electron energies Êе = 28 and 30 MeV (with a Gaussian width σе ≈ 0.7 MeV), an attempt is undertaken to search for near-threshold production of the four-neutron system in the reaction 209Bi(γ,4n)205Bi (with the threshold energy = 29.5 MeV) induced by bremsstrahlung photons. The induced activity method was applied in the experiment. The gamma-spectroscopic measurements were carried out in the underground low background laboratory of the AANL. Owing to low-background conditions in the laboratory, one achieves, at Êе = 30 MeV, reliable identification of 205Bi radionuclide and the first determination of the near-threshold cross sections of this rare process, namely, the weighted by the spectrum of bremsstrahlung photons cross-section σw = (4.42 ± 0.48) × 10–4 mb and the averaged over the spectrum of bremsstrahlung photons cross-section = (1.95 ± 0.22) mb. No 205Bi production was observed at Êе = 28 MeV. Low-background conditions allow one also to identify the rare decays of the 208Bi nucleus produced in the reaction 209Bi(γ, n)208Bi, and measure its weighted and averaged cross sections at Êе = 28 and 30 MeV: σw = (19.6 ± 3.5) and (16.4 ± 2.2) mb and = (139 ± 25) and (142 ± 19) mb, respectively. From the data at Êе= 28 MeV, an upper limit of the yield of a hypothetical four-neutron bound state (tetraneutron) production reaction relative to the yield of the reaction 209Bi(γ, n)208Bi is estimated to be 10–5. The obtained experimental data are compared with predictions of the TALYS1.9 and FLUKA models. It is shown that the measured at Êе = 30 MeV cross-section of the reaction 209Bi(γ,4n)205Bi strongly overestimates (by more than one order of magnitude) the theoretical value. This disagreement can be caused by the fact that the models do not foresee the production of correlated neutron clusters, in particular, the four-neutron resonance state with 2.4 MeV excitation energy observed recently in the reaction 1H(8He, 1H + 4He)4n. The near-threshold production of the four-neutron system, observed in the present work, can, probably, serve as an indirect indication of its resonance nature. [ABSTRACT FROM AUTHOR]

Using the induced activity method, the inclusive process 16O(γ, X)7Be of the 7Ве isotope photoproduction from oxygen nuclei was studied at the linear electron accelerator AANL (YerPhI) at the boundary energies of bremsstrahlung photons = 40 and 70 MeV. This process was first observed in the near-threshold energy range Eγ < 40 MeV in this work owing to low-background conditions in the underground laboratory of the AANL where spectroscopic measurements were carried out. The cross-section averaged over the spectrum of bremsstrahlung photons and the cross-section per equivalent photon has been measured. Estimates are also obtained for the integral cross-section of this process. The measured cross-sections are compared with the available experimental data and predictions of the TALYS1.9, GEANT4, and FLUKA models. It is shown that the predictions of TALYS and GEANT4 are strongly underestimated (especially at = 40 MeV) as compared with our data, which is associated with a strong underestimation in model computations of the role of two main near-threshold reaction channels: the 16O(γ, 9Be)7Be channel, which proceeds through the two-particle photofission mechanism and the 16O(γ, n + α + α)7Be spallation channel. The FLUKA predictions are qualitatively comparable with experimental data at Eγ < 40 MeV and Eγ = (50–60) MeV, however, they greatly exceed them in the energy range Eγ = (40–50) MeV, this excess is almost entirely caused by the overestimated contribution of the 16O(γ, n + α + α)7Be spallation reaction cross-section. The data obtained may turn out to be useful in attempts to improve theoretical models of nuclear reactions, in the study of the radioisotope content of the earth's atmosphere, and also be of interest in connection with the so-called "primary lithium problem". [ABSTRACT FROM AUTHOR]

We investigate the convergence of the quasi-periodic approximations in diferent frameworks and reveal exact asymptotic estimates of the corresponding errors. The estimates facilitate a fair comparison of the quasi-periodic approximations to other classical well-known approaches. We consider a special realization of the approximations by the inverse of the Vandermonde matrix, which makes it possible to prove the existence of the corresponding implementations, derive explicit formulas and explore convergence properties. We also show the application of polynomial corrections for the convergence acceleration of the quasi-periodic approximations. Numerical experiments reveal the auto-correction phenomenon related to the polynomial corrections so that utilization of approximate derivatives surprisingly results in better convergence compared to the expansions with the exact ones. [ABSTRACT FROM AUTHOR]

The long-living products of the 252Cf spontaneous fission are searched for with the help of a Ge(Li) detector irradiated by a 25.5 year old source in the low-background laboratory in the Avan salt mine (Yerevan). No significant photopeaks from the decays of 125Sb, 134Cs, 146Pm, 150Eu, 152Eu and 158Tb are observed in the detector response function analyzed in the energy range of 400÷1400 keV. The upper limits of their cumulative yields are estimated. Strong photopeaks are observed for two longliving isotopes, 137Cs and 154Eu. The content of the 137Cs photopeak corresponds to its cumulative yield of (5.07±0.35)·10-2, in agreement with the available data, while the contents of the 154Eu photopeaks correspond, on an average, to the yield of (1.84±0.17)·10-2, which is much larger than expected from the model predictions. The upper limits for the rates of the sodium (22Na) and cobalt (60Co) radioactivity of the 252Cf nucleus relative to the rate of the α-decay are estimated to be 1.6·10-5 and 3.5·10-7, respectively. [ABSTRACT FROM AUTHOR]

BACKGROUND: Job burnout is an important predictor of nurse retention. Reliable and valid measures are required to monitor this phenomenon internationally. OBJECTIVE: To evaluate the applicability of the Maslach burnout inventory (MBI) in international nursing research. DESIGN: Secondary analysis of cross-sectional hospital nurse survey data from eight countries. SETTINGS: Hospitals in the U.S., Canada, the U.K., Germany, New Zealand, Japan, Russia and Armenia. PARTICIPANTS: 54,738 direct care professional nurses from 646 hospitals in eight countries. METHODS: Confirmatory and exploratory factor analysis were undertaken to identify the factor structure of the MBI. The internal consistencies of the subscales were investigated. RESULTS: Exploratory factor analysis revealed three factors being extracted from the 22-item Maslach burnout inventory. In nearly all countries the two items (6 and 16) related to the 'stress' and 'strain' involved in working with people loaded on the depersonalization subscale rather than the emotional exhaustion subscale to which they were initially assigned. The three subscales exhibited high reliability with Cronbach alphas exceeding the critical value of 0.70. The correlation coefficients for the emotional exhaustion and depersonalization subscales were strong and positive. CONCLUSIONS: The 22-item Maslach burnout inventory has a similar factor structure and, with minor modifications, performed similarly across countries. The predictive validity of the emotional exhaustion and depersonalization subscales might be improved by moving the two items related to stress and strain from the emotional exhaustion to the depersonalization subscale. Nevertheless, the MBI can be used with confidence as a burnout measure among nurses internationally to determine the effectiveness of burnout reduction measures generated by institutional and national policies. [ABSTRACT FROM AUTHOR]

Objective: To provide an outcomes-evaluation of an intervention to strengthen professional nursing practice in Russian and Armenian hospitals. Design: The Nursing Quality Improvement Initiative using the ANCC Forces of Magnetism to develop professional nurse practice was implemented in four hospitals in Russia and Armenia. Cross-sectional survey data were collected at two time points from 840 nurses in Wave 1 and 859 nurses in Wave 2. Comparisons were undertaken between targeted units in each hospital compared to nontargeted units, and each hospital served as its own control in surveys that took place in years 1 and 3 of the demonstration. Methods: Descriptive information on nurse samples was derived from survey items. Changes in characteristics of nurse practice environments, nursereported patient care quality, and nurse burnout in Russia and Armenia, overall and separately for targeted and nontargeted units, were tested using chisquare statistics and difference of means tests. Findings: Practice environment features such as nurses' involvement in hospital affairs, better collegial relationships with physicians, more support for nursing care from administrators, and continuity of nursing care improved after the intervention. Resource adequacy indicators did not change over the demonstration period. Changes in indicators of patient care quality were favorable, though differences in changes in targeted and nontargeted units were equivocal. Conclusions: Changes consistent with evolving professional nursing practice were associated with program implementation. Forces of magnetism appear to have the same potential for transforming nursing practice in countries with fewer resources as in wealthier Western countries. Clinical Relevance: Magnet Recognition, an evidence-based best practice for improving the nursing-care environment developed inWestern countries, was feasible to implement in countries with transitioning economies, limited resources, and truncated professional nursing education. [ABSTRACT FROM AUTHOR]

Aims. To describe nurse burnout, job dissatisfaction and quality of care in Japanese hospitals and to determine how these outcomes are associated with work environment factors. Background. Nurse burnout and job dissatisfaction are associated with poor nurse retention and uneven quality of care in other countries but comprehensive data have been lacking on Japan. Design. Cross-sectional survey of 5956 staff nurses on 302 units in 19 acute hospitals in Japan. Methods. Nurses were provided information about years of experience, completed the Maslach Burnout Inventory and reported on resource adequacy and working relations with doctors using the Nursing Work Index-Revised. Results. Fifty-six per cent of nurses scored high on burnout, 60% were dissatisfied with their jobs and 59% ranked quality of care as only fair or poor. About one-third had fewer than four years of experience and more than two-thirds had less than 10. Only one in five nurses reported there were enough registered nurses to provide quality care and more than half reported that teamwork between nurses and physicians was lacking. The odds on high burnout, job dissatisfaction and poor-fair quality of care were twice as high in hospitals with 50% inexperienced nurses than with 20% inexperienced nurses and 40% higher in hospitals where nurses had less satisfactory relations with physicians. Nurses in poorly staffed hospitals were 50% more likely to exhibit burnout, twice as likely to be dissatisfied and 75% more likely to report poor or fair quality care than nurses in better staffed hospitals. Conclusions. Improved nurse staffing and working relationships with physicians may reduce nurse burnout, job dissatisfaction and low nurse-assessed quality of care. Relevance to clinical practice. Staff nurses should engage supervisors and medical staff in discussions about retaining more experienced nurses at the bedside, implementing strategies to enhance clinical staffing and identifying ways to improve nurse-physician working relations. [ABSTRACT FROM AUTHOR]

Precision cutting of stainless steel and copper foils with a thickness from 125 μm to 250 μm has been demonstrated. During precision cutting of intricate forms in thin foils the object is not moved, which significantly increases the accuracy of laser treatment and cutting. In self conjugated scheme of laser projective microscopy with a feedback the width of the cut varied from 3 μm to 10 μm depending on the cutting speed, depth and characteristics of the laser radiation. Micro-details in form of literal information carriers and moving parts of micro-mechanical tools are produced. [ABSTRACT FROM AUTHOR]

The present study focused on the possible protective effect of taurine supplementation under the condition of light induced retinal damage. Damage severity was assessed by estimation of ROS and ON layers thickness in the rat retina as well as quantification of taurine and aspartate, glutamate, glycine, GABA content in the albino rat retina. Obtained data are strongly indicating that 2500 lux 48 h. exposure has caused severe damage of retina and taurine supplementation has caused protection of retina especially in the peripheral part. Also, it was established that taurine prevents increasing of aspartate, glycine, glutamate and GABA, caused by constant illumination. It remains to be clarified why taurine supplementation leads to the reduction of endogenous taurine level in the rat retina under the condition of light damage [ABSTRACT FROM AUTHOR]

The results of the first stage measurements of the attenuation lengths of radio waves in the Avan salt mine are presented. The goal of these measurements was to determine the availability of the Avan salt dome to utilize it for ultrahigh energy cosmic neutrino detection by means of Askaryan method application. The necessity for additional measurements is concluded. [ABSTRACT FROM AUTHOR]