National risks within institutional transformation: socio-economic aspects

The article examines the institutional conditions and factors of national risk formation in the context of national economy development. The author is focused on the social aspects of the institutional environment transformation, the role of government, business and society at national risk managemen

Spectral Spatial Fluctuations of CMBR: Strategy and Concept of the Experiment

Spectral Spatial Fluctuations (SSF) of the Cosmic Microwave Background Radiation (CMBR) temperature are considered as a result of an interaction of primordial atoms and molecules with CMBR in proto-objects moving with peculiar velocities relative to the CMBR. Expected optimistic values of $\Delta T/T$ are 2x10^{-5}--2x10^{-6}$for SSF caused by HeH$^+$at z =20-30 which are possible redshifts of early reionization scenario. The bandwidth of the lines is 0.1-2depending on the scale of proto-objects and redshifts. For the SSF search CMBR maps in different spectral channels are to be observed and then processed by the Difference method. Simulation of the experiment is made for MSRT (Tuorla Observatory, Finland) equipped with a 7x4 beam cryo-microbolometer array with a chopping flat and frequency multiplexer providing up to 7 spectral channels in each beam (88-100 GHz). Expected$\Delta $T/T limit in the experiment is 2x10$^{-5}$ with 6'-7' angular and 2% frequency resolution. Simulation shows that SSF may be recognized in the angular power spectrum when S/N in single frequency CMBR maps is as small as 1.17 or even something less for white noise. Such an experiment gives us a possibility to set upper limit of SSF in MM band and prepare future SSF observations.Comment: 26 pages, 6 figure

The superheated Melting of Grain Boundary

Based on a model of the melting of Grain Boundary (GB), we discuss the possibility of the existence of superheated GB state. A Molecular Dynamics simulation presented here shows that the superheated GB state can realized in the high symmetric tilt GB. Whether the sizes of liquid nuclei exceed a critical size determined the superheating grain boundary melting or not. Our results also indicate that the increase of melting point due to pressure is smaller than the superheating due to nucleation mechanism.Comment: Accepted by PRB, 7 pages and 5 figure

Stability of multi-electron bubbles in liquid helium

The stability of multi-electron bubbles in liquid helium is investigated theoretically. We find that multi-electron bubbles are unstable against fission whenever the pressure is positive. It is shown that for moving bubbles the Bernoulli effect can result in a range of pressures over which the bubbles are stable.Comment: 7 pages, 5 figure

The water vapour distribution in the Arctic lowermost stratosphere during the LAUTLOS campaign and related transport processes including stratosphere-troposphere exchange

International audienceBalloon-borne water vapour measurements during January and February 2004, which were obtained as part of the LAUTLOS campaign at Sodankylä, Finland, 67° N, were used to analyse the water vapour distribution in the wintertime Arctic lowermost stratosphere. A 2.5 km thick layer (or 30 K in the potential temperature scale) above the tropopause is characterized by a significant water vapour variability on a synoptic timescale with values between stratospheric and tropospheric, which is in good agreement with previously reported measurements. A cross-correlation analysis of ozone and water vapour confirms that this layer contains a mixture of stratospheric and tropospheric air masses. Some of the flights sampled laminae of enhanced water vapour above the tropopause. Meteorological analyses and backward trajectory calculations show that these features were related to filaments that had developed along the flanks of cut-off anticyclones, which had been active at this time over the Northern Atlantic. The role of the filaments was however not to transport water vapour from the troposphere to the stratosphere but rather to transport it within the stratosphere away from regions where intensive two-way stratosphere-troposphere exchange (STE) was identified. Intensive STE occurred around cut-off anticyclones in regions of strong winds, where calculations suggest the presence of clear-air turbulence (CAT). Evidences that CAT contributes to the troposphere-to-stratosphere transport (TST) are presented. However, statistically, relation between TST and CAT during the studied period is weak

The water vapour distribution in the Arctic lowermost stratosphere during LAUTLOS campaign and related transport processes including stratosphere-troposphere exchange

International audienceBalloon-borne water vapour measurements during January and February 2004, which were obtained as part of the LAUTLOS campaign at Sodankylä, Finland, 67° N, were used to analyse the water vapour distribution in the wintertime Arctic lowermost stratosphere. A 2.5 km thick layer (or 30 K in the potential temperature scale) above the local tropopause is characterized by a significant water vapour variability on a synoptic timescale with values between stratospheric and tropospheric, which is in good agreement with previously reported measurements. A cross-correlation analysis of ozone and water vapour confirms that this layer contains a mixture of stratospheric and tropospheric air masses. Some of the flights sampled laminae of enhanced water vapour above the tropopause. Meteorological analyses and backward trajectory calculations show that these features are related to filaments that had developed along the flanks of cut-off anticyclones, which had been active at this time over the Northern Atlantic. Cross-tropopause mass fluxes calculated following the Wei method are used to identify regions and processes that are important for stratosphere-troposphere exchange (STE) in high-latitudes. Intensive STE occurs around cut-off anticyclones in regions of strong winds, where calculations suggest the presence of developed clear-air turbulence. The decay of the filaments is also shown to be important for STE

Analysis of the RATAN-600 radiotelescope antenna with a multilevel Physical Optics algorithm

International audienceThe RATAN-600 antenna is a flexible multireflector system composed of reflectors of very large dimensions. An extended system, with improved performance in the millimetric range, includes a focal receiver array. Accurate electromagnetic analysis of such a system, and simulation of three-dimensional (3D) patterns, represents a substantial computational challenge. A fast Physical Optics method based on a multilevel subdivision of the surfaces of integration is proposed to address this problem. This method allows to perform Physical Optics integrals with a computational complexity comparable to that of the Fast Fourier Transform. The algorithm and initial numerical results of its application to the RATAN-600 antenna system are presented

Electric field induced strong localization of electrons on solid hydrogen surface: possible applications to quantum computing

Two-dimensional electron system on the liquid helium surface is one of the leading candidates for constructing large analog quantum computers (P.M. Platzman and M.I. Dykman, Science 284, 1967 (1999)). Similar electron systems on the surfaces of solid hydrogen or solid neon may have some important advantages with respect to electrons on liquid helium in quantum computing applications, such as larger state separation $\Delta E$, absence of propagating capillary waves (or ripplons), smaller vapor pressure, etc. As a result, it may operate at higher temperatures. Surface roughness is the main hurdle to overcome in building a realistic quantum computer using these states. Electric field induced strong localization of surface electrons is shown to be a convenient tool to characterize surface roughness.Comment: 4 pages, 3 figure

City as an Object of Ecological and Economic Researches: the Example of Russian Cities

The growth of environmental pollution especially in big cities dictates the need to search for the reasons of this trend, most of which refer to the economic sphere. The aim of this work is not only to describe the state of environment in Russian cities with the population of 100 thousand inhabitants and more, but also to reveal the main economic factors that influence on the intensity of their environmental pollution. The ecological and economic analysis of Russian cities, fulfilled in this work, helped to identify the most unfavourable of them in terms of the level of environmental impact. The low quality of environment in these cities is largely due to natural and climatic conditions (bad conditions for contaminants dispersion) and specifics of their economic development: functioning of large industrial enterprises of ferrous and non-ferrous metallurgy, petro chemistry, construction industry. The conclusion is that to improve the environmental quality in these cities comprehensive social, environmental and economic solutions are required

Spline-Profile Horn for Array Applications in Radio Astronomy

In this paper the properties of an optimized compact smooth-walled spline-profile horn for the 30 ÷38 GHz frequency band is described. The measured 3 dB beamwidths are 40° in the H-plane, 37° in the E-plane, and 38° in the 45° -plane. The measured sidelobe levels are less than –30 dB in H-plane, –23 dB in E-plane, and –25 dB in 45° -plane. The maximum gain is 13.8 dBi. The measured crosspolarization level is less than –20 dB at the top of the band. The antenna measurement and test results are in good agreement with simulation. The results of the trial observations at the RATAN-600 radio telescope with the horn are given. We consider using such a horn as an efficient element in a multi-beam receiving array for a radio telescope.В роботі описано оптимізований компактний гладкостінний рупор зі сплайн-профілем для діапазону частот 30 ÷38 ГГц. Виміряна ширина діаграми спрямованості на рівні –3 дБ була 40° у H-площині, 37° у E-площині, 38° у 45° -площині. Виміряний рівень бокових пелюсток –30 дБ в H-площині, –23 дБ в E-площині, –25 дБ у 45° -площині. Максимальний рівень коефіцієнтa підсилювання був 13.8 дБ. У верхній частині діапа- зону виміряний рівень кросс-поляризації був нижчим –20 дБ. Результати чисельного моделювання добре співвідносяться з результатами експериментального дослідження. Наведено результати тестових вимірювань на радіотелескопі РАТАН-600 з розглянутим рупором. Ми вважаємо, що описаний рупор може бути використаний у якості ефективного елементу в багатопроменевих приймальних решітках радіотелескопа.В работе описаны свойства оптимизированного компактного гладкостенного рупора со сплайн-профилем для диапазона частот 30 ÷38 ГГц. Измеренная ширина диаграммы направленности на уровне –3дБ равна 40° в H-плоскости, 37° в E-плоскости, и 38° в 45° -плоскости. Измеренный уровень боковых лепестков меньше чем –30 дБ в H-плоскости, –23 дБ в E-плоскости и –25 дБ в 45° -плоскости. Максимальный уровень коэффициента усиления равен 13.8 дБ. В верхней части диапазона измеренный уровень кросс-поляризации меньше –20 дБ. Результаты численного моделирования хорошо соответствуют результатам экспериментального исследования. Приведены результаты тестовых измерений на радиотелескопе РАТАН-600 с предложенным рупором. Мы считаем, что представленный рупор может быть использован как эффективный элемент в многолучевых приемных решетках радиотелескопа