33 research outputs found
Polariton Pattern Formation and Photon Statistics of the Associated Emission
We report on the formation of a diverse family of transverse spatial polygon patterns in a microcavity
polariton fluid under coherent driving by a blue-detuned pump. Patterns emerge spontaneously
as a result of energy-degenerate polariton-polariton scattering from the pump state to interfering
high order vortex and antivortex modes, breaking azimuthal symmetry. The interplay between a
multimode parametric instability and intrinsic optical bistability leads to a sharp spike in the value
of second order coherence g (2)(0) of the emitted light, which we attribute to the strongly superlinear
kinetics of the underlying scattering processes driving the formation of patterns. We show numerically
by means of a linear stability analysis how the growth of parametric instabilities in our system
can lead to spontaneous symmetry breaking, predicting the formation and competition of different
pattern states in good agreement with experimental observations
Development of alternatives for accelerating structure in the range of intermediate proton energy
A scope of the linear accelerating structures for acceleration proton high rower beams in energy range 5…
100 MeV is presented. Main task lies in a possibility to use superconductive equipment. The results are given for
+original desgn of accelerating structures of alternating segments being excited on E11-wave on π/2-mode. A possibility is discussed about the use of focusing blocks with the RF–quadrupoles which uniformly fit into the chain of
accelerating cells.Приводиться огляд розробок конструкцій структур лінійних прискорювачів протонів з високою
потужністю пучка в діапазоні енергій 5...100 МеВ. Основна вимога полягає в можливості використання
надпровідної техніки. Описані результати оригінальних розробок прискорюючої структури типу зустрічних
сегментів, що збуджується на Е11-хвилі, а також можливість застосування фокусуючих блоків з ВЧ-квадруполями, які однорідно вписуюються в цепочку прискорюючих комірок.Приводится обзор разработок конструкций структур линейных ускорителей протонов с большой мощностью пучка в диапазоне энергий 5...100 МэВ. Главная задача заключается в возможности использования сверхпроводящей техники. Описаны результаты оригинальных разработок ускоряющей структуры типа встречных
сегментов, возбуждаемой на Е11-волне, и возможность применения фокусирующих блоков с ВЧ – квадруполями, которые однородно вписываются в цепочку ускоряющих ячеек
Contemporary water policy of Kyrgyzstan
The policy of Kyrgyzstan in water-energy resources management was formed after breakup of the Soviet Union when new independent states appeared. The Central Asian countries used the principle of assigning quotas on water resources which was widely practiced in the Soviet period. However, soon it has become clear that this approach is not in the interests of Kyrgyzstan. The country that practically had no hydrocarbon and quality coal resources could satisfy its energy needs only by hydropower plants on transboundary rivers. However, as soon as the countries of this region became independent, their interests turned out to be at variance. Kyrgyzstan as well as Tajikistan locates in the upper reaches of transboundary rivers and is interested in accumulation of water in reservoirs in summer for their further use in winter for power generation. On the contrary, the downstream countries, such as Kazakhstan, Uzbekistan, and Turkmenistan, possessing extensive agricultural areas, are interested in getting water resources in summer. The directly opposing goals of the Central Asian countries provoked conflicts among them. Having faced the difficulties in addressing the water-energy issues in the multilateral format, Kyrgyzstan consistently pursues the policy targeted to full control of water resources formed in its territory. It adopted the laws aimed at formation of the market-based relations with neighboring states in respect of water resources of cross-country waterways. At the same time, Kyrgyzstan follows the course of construction of large water-energy facilities which should enhance its opportunities for addressing the energy security issues. However, these plans of Kyrgyzstan are criticized by other Central Asian countries that see in such policy a threat to their interests, first of all, for agriculture and solution of social and economic problems. © Springer Nature Switzerland AG 2018
Transboundary rivers in Central Asia: Cooperation and conflicts among countries
Nowadays many scientists and specialists say that in the twenty-first century, not hydrocarbons but water will be the key issue for economic development, well-being, and quality of life. This fully applies to the Central Asian countries where historically the problems of water resources have been in the focus of attention as the main factors determining stability in all sectors of the economy. This is connected with their geographical location and specific natural conditions. The Central Asian states locate in a region with severe climate featuring very high temperatures, uneven spatial distribution of water resources, and their insufficiency as no mechanism for addressing water issues is available. By the early twenty-first century, all water supply reserves in the region have been practically exhausted. The situation is aggravated by the fact that the river basins in this region are transboundary and their watersheds do not coincide with the existing state borders. In addition, the economies of the Central Asian countries depend enormously on the use of transboundary water resources adding complexity to the water relations among these states which may be fraught with ethnic and social conflicts. The problem is aggravated by differing hydropower priorities of the countries located in the upper reaches of rivers, such as Tajikistan and Kyrgyzstan that control more than 80% of all freshwater supplies, and agricultural needs of the downstream countries – Uzbekistan, Kazakhstan, and Turkmenistan. In other words, some of the countries need electricity, while others water for irrigated farming. This problem remains in the focus of attention due to a number of factors typical of the Central Asian region: the apparent political stability of local elites tested periodically by civil confrontations, “smoldering” military conflict in adjacent Afghanistan, high population growth rates, and the presence of ecological disaster zones – drying up of the Aral Sea, desertification, etc. In addition, water management in the Central Asian countries is being adapted to the new economic conditions. There are also the imbalance between the number of the population and the amount of available resources required to meet their vital needs (food, water, etc.), acceleration of climate change processes leading to the growing number of extreme weather conditions such as floods and droughts, and contamination of water sources resulting in deteriorated sanitary conditions. Fair and sustainable management of shared water resources requires legal regulation, the institutions that are capable to ensure the holistic approach to this problem, and effective methods for solving it. Regardless of the surviving problems, the international experience has shown that in case of joint management of transboundary river basins, the interstate water conflicts usually tend to give way to cooperation. Depending on the emerging political situation, water problems can be a factor of rapprochement or disintegration of the Central Asian states. © Springer International Publishing AG 2018
Professional-Public Mechanisms Assess the Qualifications of Educators
The article describes the progress of work on the project "Professional and public mechanisms for assessing the qualifications of educators " implemented by the Pedagogical Association «XXI century educator» using the grant of the President of the Russian Federation for the development of civil society provided by the Foundation for Presidential Grants (No. 17-1-008266) and its main results. Based on the current achievements of Russian and foreign pedagogical science and practice, in accordance with the professional standard of the educator and taking into account the current formation and introduction of the national system of teacher growth, proposals have been developed for assessing the qualifications (labor actions) of educators in the form of draft normative legal act and methodological recommendations. The necessity of active and wide participation of the professional pedagogical community in the organization and evaluation of the qualification of pedagogical workers as a necessary condition for building an effective system ensuring the professional growth of educators is substantiated
Characterization of Landsat-7 to Landsat-8 reflective wavelength and normalized difference vegetation index continuity
AbstractAt over 40years, the Landsat satellites provide the longest temporal record of space-based land surface observations, and the successful 2013 launch of the Landsat-8 is continuing this legacy. Ideally, the Landsat data record should be consistent over the Landsat sensor series. The Landsat-8 Operational Land Imager (OLI) has improved calibration, signal to noise characteristics, higher 12-bit radiometric resolution, and spectrally narrower wavebands than the previous Landsat-7 Enhanced Thematic Mapper (ETM+). Reflective wavelength differences between the two Landsat sensors depend also on the surface reflectance and atmospheric state which are difficult to model comprehensively. The orbit and sensing geometries of the Landsat-8 OLI and Landsat-7 ETM+ provide swath edge overlapping paths sensed only one day apart. The overlap regions are sensed in alternating backscatter and forward scattering orientations so Landsat bi-directional reflectance effects are evident but approximately balanced between the two sensors when large amounts of time series data are considered. Taking advantage of this configuration a total of 59 million 30m corresponding sensor observations extracted from 6317 Landsat-7 ETM+ and Landsat-8 OLI images acquired over three winter and three summer months for all the conterminous United States (CONUS) are compared. Results considering different stages of cloud and saturation filtering, and filtering to reduce one day surface state differences, demonstrate the importance of appropriate per-pixel data screening. Top of atmosphere (TOA) and atmospherically corrected surface reflectance for the spectrally corresponding visible, near infrared and shortwave infrared bands, and derived normalized difference vegetation index (NDVI), are compared and their differences quantified. On average the OLI TOA reflectance is greater than the ETM+ TOA reflectance for all bands, with greatest differences in the near-infrared (NIR) and the shortwave infrared bands due to the quite different spectral response functions between the sensors. The atmospheric correction reduces the mean difference in the NIR and shortwave infrared but increases the mean difference in the visible bands. Regardless of whether TOA or surface reflectance are used to generate NDVI, on average, for vegetated soil and vegetation surfaces (0≤NDVI≤1), the OLI NDVI is greater than the ETM+ NDVI. Statistical functions to transform between the comparable sensor bands and sensor NDVI values are presented so that the user community may apply them in their own research to improve temporal continuity between the Landsat-7 ETM+ and Landsat-8 OLI sensor data. The transformation functions were developed using ordinary least squares (OLS) regression and were fit quite reliably (r2 values>0.7 for the reflectance data and >0.9 for the NDVI data, p-values<0.0001)