Landau damping in thin films irradiated by a strong laser field

The rate of linear collisionless damping (Landau damping) in a classical electron gas confined to a heated ionized thin film is calculated. The general expression for the imaginary part of the dielectric tensor in terms of the parameters of the single-particle self-consistent electron potential is obtained. For the case of a deep rectangular well, it is explicitly calculated as a function of the electron temperature in the two limiting cases of specular and diffuse reflection of the electrons from the boundary of the self-consistent potential. For realistic experimental parameters, the contribution of Landau damping to the heating of the electron subsystem is estimated. It is shown that for films with a thickness below about 100 nm and for moderate laser intensities it may be comparable with or even dominate over electron-ion collisions and inner ionization.Comment: 15 pages, 2 figure

Intercultural Communication and Values-Based Orientations of Youth: Social Mobility and Problems of Self-Realisation

The ability to interact at the level of interpersonal communication allows to say that young people not only perceive society as an environment for their self-realisation, but also use it to gain new experience, that can determine the development of an individual. The relevance of the study is determined by the fact that each act of communication must be implemented for the purposes of development under certain conditions that affect not only the communication environment itself, but also other forms of interaction at the level of the individual, communality or community. The novelty of the subject matter is determined by the fact that the formation of intercultural communication is possible only if programs of social mobility and, accordingly, cultural exchange are implemented. The authors show that such progress is most likely to be achieved in the external environment, which is determined by the presence of external influences. The authors of the paper primarily refer to this effect as the environment of an educational institution. The leading research method is a sociological survey and the method of analysis, which make it possible to comprehensively consider the value priorities and preferences that are characteristic of modern student youth. The practical significance of the study is determined by structuring and factor analysis, which allows to distribute the cultural layer into various social groups and ensure youth intercultural exchange both in the context of local student communication and in the context of an increase in the level of academic mobility

Investigation converter circuit "voltage-current" for power calibrator

The paper presents alternative circuits for voltage-current converters to be used in the calibrator of fictitious power. The experimental studies have revealed a number of problems related to the stability of the system in deep feedback and zero level stabilization of the amplifier. The circuit solutions given in the article allow elimination of these problems and improve the accuracy of calibrator current calibration. For example, correction/corrective circuits are used to ensure the stability of the converter at deep depths of the feedback, and operational amplifier based circuit solution and compensation condition are proposed to reduce the additional phase shift. To improve the accuracy of the calibration current values specified by the calibrator we propose to connect the feedback circuit to the measuring current transformer. However, further improvement of the accuracy class of the power calibrator is impossible without modern electronic components

Three-body correlations in direct reactions: Example of 6^{6}Be populated in (p,n)(p,n) reaction

The $^{6}$Be continuum states were populated in the charge-exchange reaction $^1$H($^{6}$Li,$^{6}$Be)$n$ collecting very high statistics data ($\sim 5 \times 10^6$ events) on the three-body $\alpha$+$p$+$p$ correlations. The $^{6}$Be excitation energy region below $\sim 3$ MeV is considered, where the data are dominated by contributions from the $0^+$ and $2^+$ states. It is demonstrated how the high-statistics few-body correlation data can be used to extract detailed information on the reaction mechanism. Such a derivation is based on the fact that highly spin-aligned states are typically populated in the direct reactions.Comment: submitted to Physical Review

New insight into the low-energy 9^9He spectrum

The spectrum of $^9$He was studied by means of the $^8$He($d$,$p$)$^9$He reaction at a lab energy of 25 MeV/n and small center of mass (c.m.) angles. Energy and angular correlations were obtained for the $^9$He decay products by complete kinematical reconstruction. The data do not show narrow states at $\sim$1.3 and $\sim$2.4 MeV reported before for $^9$He. The lowest resonant state of $^9$He is found at about 2 MeV with a width of $\sim$2 MeV and is identified as $1/2^-$. The observed angular correlation pattern is uniquely explained by the interference of the $1/2^-$ resonance with a virtual state $1/2^+$ (limit on the scattering length is obtained as $a > -20$ fm), and with the $5/2^+$ resonance at energy $\geq 4.2$ MeV.Comment: 5 pages, 4 figures, 2 table

10He low-lying states structure uncovered by correlations

The 0+ ground state of the 10He nucleus produced in the 3H(8He,p)10He reaction was found at about $2.1\pm0.2$ MeV (\Gamma ~ 2 MeV) above the three-body 8He+n+n breakup threshold. Angular correlations observed for 10He decay products show prominent interference patterns allowing to draw conclusions about the structure of low-energy excited states. We interpret the observed correlations as a coherent superposition of the broad 1- state having a maximum at energy 4-6 MeV and the 2+ state above 6 MeV, setting both on top of the 0+ state "tail". This anomalous level ordering indicates that the breakdown of the N=8 shell known in 12Be thus extends also to the 10He system.Comment: 5 pages, 5 figure

Функциональное состояние кардиореспираторной системы после ортотопической трансплантации сердца с длительной холодовой ишемией трансплантата

Objective: to assess the functional state of the cardiorespiratory system in the long term after orthotopic heart transplantation (HT) with prolonged cold ischemia time. Materials and methods. The results of 60 orthotopic HTs performed at Meshalkin National Medical Research Center were analyzed. A comparison was made of the immediate and long-term outcomes of HTs in the group with cold ischemia time lasting for less than 240 minutes and in those with farther distance between donor and recipient sites with cold ischemia time of 240 minutes or more. In the long-term follow-up after HT, all patients underwent cardiopulmonary exercise testing, body plethysmography, assessment of the diffusing capacity of the lungs, and quality of life assessment. Results. Prolonged cold ischemia showed a negative effect on the early postoperative period – decreased myocardial contractility on postoperative day 1 and longer duration of inotropic support. At the same time, the survival rate and incidence of graft rejection reactions in the early and late post-HT periods in the studied groups did not differ significantly. Peak oxygen consumption in the general group in the long term after HT was 17 (14.7–21.0) mL/kg/min, VE/ VCO2 slope was 30 (29–36) at 100 (90–120) W threshold load power. All the parameters of pulmonary function tests did not differ significantly depending on cold ischemia duration. Quality of life also did not show significant differences depending on the duration of graft ischemia in terms of both physical and psycho-emotional health components of the SF-36 questionnaire. Conclusion. Long-term cold ischemia of the graft did not show any negative impact on the functional state of the cardiorespiratory system and quality of life in the long term after HT. The studied group of recipients was characterized by high efficiency of pulmonary ventilation and gas exchange, as well as high tolerance to physical activity in the long-term post-HT period.Цель. Оценка функционального состояния кардиореспираторной системы в отдаленные сроки после ортотопической трансплантации сердца (ТС) с длительной холодовой ишемией трансплантата. Материалы и методы. Проанализированы результаты 60 ортотопических ТС, выполненных в ФГБУ «НМИЦ им. акад. Е.Н. Мешалкина» Минздрава России. Проведено сравнение непосредственных и отдаленных результатов ТС в группах с холодовой ишемией трансплантата менее 240 минут и при дистанционном изъятии с холодовой ишемией 240 минут и более. В отдаленные сроки после ТС всем пациентам проведено кардиопульмональное нагрузочное тестирование, бодиплетизмография, оценка диффузионной способности легких, оценка качества жизни. Результаты. Длительная холодовая ишемия донорского сердца показала негативное влияние на ранний послеоперационный период ТС в виде снижения сократительной способности миокарда в первые сутки после операции и увеличения длительности инотропной поддержки. При этом выживаемость и частота развития реакций отторжения трансплантата в ранние и отдаленные сроки после ТС в изучаемых группах значимо не различалась. Пиковое потребление кислорода в отдаленные сроки после ТС в общей группе составило 17 (14,7–21,0) мл/мин/кг, VE/VCO2 slope – 30 (29–36) при пороговой мощности нагрузки 100 (90–120) Вт. Все параметры легочных функциональных тестов не имели значимых отличий в зависимости от длительности холодовой ишемии. Качество жизни также не показало значимых различий в зависимости от длительности ишемии трансплантата как по физическому, так и психоэмоциональному компонентам здоровья опросника SF-36. Заключение. Длительная холодовая ишемия трансплантата не показала отрицательного влияния на функциональное состояние кардиореспираторной системы и качество жизни в отдаленные сроки после ТС. Изучаемая группа реципиентов характеризовалась высокой эффективностью легочной вентиляции и газообмена, а также высокой толерантностью к физическим нагрузкам в отдаленные сроки после ТС

Multiphoton detachment of electrons from negative ions

A simple analytical solution for the problem of multiphoton detachment from negative ions by a linearly polarized laser field is found. It is valid in the wide range of intensities and frequencies of the field, from the perturbation theory to the tunneling regime, and is applicable to the excess-photon as well as near-threshold detachment. Practically, the formulae are valid when the number of photons is greater than two. They produce the total detachment rates, relative intensities of the excess-photon peaks, and photoelectron angular distributions for the hydrogen and halogen negative ions, in agreement with those obtained in other, more numerically involved calculations in both perturbative and non-perturbative regimes. Our approach explains the extreme sensitivity of the multiphoton detachment probability to the asymptotic behaviour of the bound-state wave function. Rapid oscillations in the angular dependence of the $n$-photon detachment probability are shown to arise due to interference of the two classical trajectories which lead to the same final state after the electron emerges at the opposite sides of the atom when the field is close to maximal.Comment: 27 pages, Latex, and PostScript figures fig1.ps, fig2.ps, fig3.ps, accepted for publication in Phys. Rev.

CURRENT PRINCIPLES FOR CRANIOPHARYNGIOMA TREATMENT

The paper describes the classification and treatment options of craniopharyngiomas, benign epithelial tumors arising from the cell remains of the Rathke’s pouch. It presents a few types of surgical accesses during surgical treatment for this disease and gives examples of how to place an Ommaya reservoir