Nonequilibrium Bose systems and nonground-state Bose-Einstein condensates

The theory of resonant generation of nonground-state Bose-Einstein condensates is extended to Bose-condensed systems at finite temperature. The generalization is based on the notion of representative statistical ensembles for Bose systems with broken global gauge symmetry. Self-consistent equations are derived describing an arbitrary nonequilibrium nonuniform Bose system. The notion of finite-temperature topological coherent modes, coexisting with a cloud of noncondensed atoms, is introduced. It is shown that resonant generation of these modes is feasible for a gas of trapped Bose atoms at finite temperature.Comment: Latex file, 16 pages, no figure

Limits and Possible Consequences of the Development of Agricultural Production: Modeling Agricultural Situations in the Stavropol Territory, USSR

The Food and Agriculture Program at IIASA focuses its research activities on understanding the nature and dimension of the world's food situation and problems, on exploring possible alternative policies which could improve the present situation in the short and long term, and on investigating the consequences of such policies at various levels - global, national and regional -- and in various time horizons. One part of the research activities focussed on investigations of alternative paths of technology transformation in agriculture with respect to resource limitations and environmental consequences in the long term. The general approach and methodology developed for this investigation is being applied in several case studies on the regional level. The reason for the studies is not only to validate the general methodology but also to develop an applicable tool for detailed investigations for a particular region which could then be applied on a number of similar regions. Furthermore, some specific aspects are being addressed in all these case studies which has been initiated within the IIASA's Food and Agriculture Program. This will allow the behavior of various systems to be compared, according to the selected aspects, and analyzed (in different social, economic and natural resource conditions) according to the selected aspects. One of these case studies is of Stavropol, USSR, and covers the whole of this region. This paper describes the first phase of the study, the problems in this region, the aims for solving them, and the first draft of the methodology which is based on the general framework developed at IIASA

Normal and Anomalous Averages for Systems with Bose-Einstein Condensate

The comparative behaviour of normal and anomalous averages as functions of momentum or energy, at different temperatures, is analysed for systems with Bose-Einstein condensate. Three qualitatively distinct temperature regions are revealed: The critical region, where the absolute value of the anomalous average, for the main energy range, is much smaller than the normal average. The region of intermediate temperatures, where the absolute values of the anomalous and normal averages are of the same order. And the region of low temperatures, where the absolute value of the anomalous average, for practically all energies, becomes much larger than the normal average. This shows the importance of the anomalous averages for the intermediate and, especially, for low temperatures, where these anomalous averages cannot be neglected.Comment: Latex file, 17 pages, 6 figure

Low Threshold Parametric Decay Instabilities in ECRH experiments at toroidal devices

The experimental conditions leading to substantial reduction of backscattering decay instability threshold in ECRH experiments in toroidal devices are analyzed. It is shown that drastic decrease of threshold is provided by non monotonic behaviour of plasma density, which is often observed due to so-called density-pump-out effect or presence of magnetic islands, and by poloidal magnetic field inhomogeniety making possible localization of ion Bernstein decay waves. The corresponding ion Bernstein wave gain and the parametric decay instability pump power threshold is calculated. The possible experimental consequences of easy backscattering decay instability excitation are discussed.Comment: 12 pages, 8 figures, submitted to Nuclear Fusio

Self-Consistent Theory of Bose-Condensed Systems

In the theory of Bose-condensed systems, there exists the well known problem, the Hohenberg-Martin dilemma of conserving versus gapless approximations. This dilemma is analysed and it is shown that it arises because of the internal inconsistency of the standard grand ensemble, as applied to Bose-systems with broken global gauge symmetry. A solution of the problem is proposed, based on the notion of representative statistical ensembles, taking into account all constraints imposed on the system. A general approach for constructing representative ensembles is formulated. Applying a representative ensemble to Bose-condensed systems results in a completely self-consistent theory, both conserving and gapless in any approximation.Comment: Latex file, 12 page

Variational self-consistent theory for trapped Bose gases at finite temperature

We apply the time-dependent variational principle of Balian-V\'en\'eroni to a system of self-interacting trapped bosons at finite temperature. The method leads to a set of coupled non-linear time dependent equations for the condensate density, the thermal cloud and the anomalous density. We solve numerically these equations in the static case for a harmonic trap. We analyze the various densities as functions of the radial distance and the temperature. We find an overall good qualitative agreement with recent experiments as well as with the results of many theoretical groups. We also discuss the behavior of the anomalous density at low temperatures owing to its importance to account for many-body effects.Comment: 8 pages, 8 figure

The N-methyl-d-aspartate receptor antagonist CPP alters synapse and spine structure and impairs long-term potentiation and long-term depression induced morphological plasticity in dentate gyrus of the awake rat

Long-term morphological synaptic changes associated with homosynaptic long-term potentiation (LTP) and heterosynaptic long-term depression (LTD) in vivo, in awake adult rats were analyzed using three-dimensional (3-D) reconstructions of electron microscope images of ultrathin serial sections from the molecular layer of the dentate gyrus. For the first time in morphological studies, the specificity of the effects of LTP and LTD on both spine and synapse ultrastructure was determined using an N-methyl-d-aspartate (NMDA) receptor antagonist CPP (3-[(R)-2-carboxypiperazin-4-yl]-propyl-1-phosphonic acid). There were no differences in synaptic density 24 h after LTP or LTD induction, and CPP alone had no effect on synaptic density. LTP increased significantly the proportion of mushroom spines, whereas LTD increased the proportion of thin spines, and both LTP and LTD decreased stubby spine number. Both LTP and LTD increased significantly spine head evaginations (spinules) into synaptic boutons and CPP blocked these changes. Synaptic boutons were smaller after LTD, indicating a pre-synaptic effect. Interestingly, CPP alone decreased bouton and mushroom spine volumes, as well as post-synaptic density (PSD) volume of mushroom spines.These data show similarities, but also some clear differences, between the effects of LTP and LTD on spine and synaptic morphology. Although CPP blocks both LTP and LTD, and impairs most morphological changes in spines and synapses, CPP alone was shown to exert effects on aspects of spine and synaptic structure

ЭКОЛОГИЧЕСКИЙ МОНИТОРИНГ ЗАГРЯЗНЕНИЯ ВОЗДУХА В ОПЕРАЦИОННОЙ КЛИНИКЕ ВСПОМОГАТЕЛЬНЫХ РЕПРОДУКТИВНЫХ ТЕХНОЛОГИЙ

The study was conducted to evaluate dynamics of air pollution during inhalational anaesthesia with sevoflurane in In Vitro Fertilization. Measurements of volatile organic compounds (VOC) were performed using portable photoionization gas analyzer in 5 areas of operating room during 7 working days and near the patient’s head and in the location of anaesthesia apparatus during 14 days without additional air cleaning. Then we used air carbone filter and measured VOC during next 14 days (49 anaesthesias altogether). Maximal air pollution was detected in the awakening period. There were no VOC traces in the area of embryologist during all periods of inhalational anaesthesia. It was shown that air pollution level reduced significantly after air carbone filter installation.В работе проведена оценка динамики загрязнения воздуха при выполнении ингаляционной анестезии севофлураном во время хирургических манипуляций для экстракорпорального оплодотворения (ЭКО). В течение 14 рабочих дней проводились измерения концентрации органических летучих соединений в операционной в зоне наркозного аппарата и в течение семи дней в зонах нахождения различных специалистов во время операции без дополнительных методов очистки воздуха, а затем в течение 14 дней с использованием ультрафиолетовых облучателей-рециркуляторов воздуха ОРУБ-3-5-«КРОНТ» (торговая марка «ДЕЗАР» с установленными воздушными угольными фильтрами ФУС-«КРОНТ» (всего 49 анестезий). Максимальный уровень загрязнения обнаружен на этапе пробуждения пациенток, при этом в зоне работы эмбриолога следов летучих органических соединений не было в течение всего времени ингаляционной анестезии. После применения методов дополнительной очистки с помощью угольных фильтров, установленных в систему рециркуляции, отмечалось достоверное уменьшение уровня загрязнения воздуха

Representative statistical ensembles for Bose systems with broken gauge symmetry

Bose-condensed systems with broken global gauge symmetry are considered. The description of these systems, as has been shown by Hohenberg and Martin, possesses an internal inconsistency, resulting in either nonconserving theories or yielding an unphysical gap in the spectrum. The general notion of representative statistical ensembles is formulated for arbitrary statistical systems, equilibrium or not. The principal idea of this notion is the necessity of taking into account all imposed conditions that uniquely define the given statistical system. Employing such a representative ensemble for Bose-condensed systems removes all paradoxes, yielding a completely self-consistent theory, both conserving and gapless in any approximation. This is illustrated for an equilibrium uniform Bose system.Comment: 43 pages, Latex fil