Hidden Symmetries of the Open N=2 String

It is known for ten years that self-dual Yang-Mills theory is the effective field theory of the open N=2 string in 2+2 dimensional spacetime. We uncover an infinite set of abelian rigid string symmetries, corresponding to the symmetries and integrable hierarchy of the self-dual Yang-Mills equations. The twistor description of the latter naturally connects with the BRST approach to string quantization, providing an interpretation of the picture phenomenon in terms of the moduli space of string backgrounds.Comment: 24 pages, no figures; v2: typos correcte

Clusters as the competitive advantages of regional economies

Текущие экономические исследования регионального развития развиваются с учетом кластерного подхода, сущность которого раскрыта в данной статьеКамышанченко, Е.Н.Растопчина, Ю.Л

On the estimate of the sigma^(I = 1)_(KN)(0)-term value from the energy level shift of kaonic hydrogen in the ground state

Using the experimental data on the energy level shift of kaonic hydrogen in the ground state (the DEAR Collaboration, Phys. Rev. Lett. 94, 212302 (2005)) and the theoretical value of the energy level shift, calculated within the phenomenological quantum field theoretic approach to the description of strong low-energy anti-K N and anti-K NN interactions developed at Stefan Meyer Institut fuer subatomare Physik in Vienna, we estimate the value of the sigma^(I = 1)_(KN)(0)-term of low-energy anti-K N scattering. We get sigma^(I = 1)_(KN)(0) = (433 +/- 85) MeV. This testifies the absence of strange quarks in the proton structure.Comment: 7 pages, no figure

Innovation as a Factor in Sustainable Development of Russia’s Agriculture

Sustainable agriculture is an integral aspect of the sustainable development of a socio-economic system. In this regard, innovation is considered to be one of the leading factors ensuring the development of sustainable agricultural since it increases the efficiency and competitiveness of the industry in the domestic and foreign markets. This study presents a system of recursive equations characterizing the innovations occurring within agricultural organizations in the regions of the Russian Federation. Additionally, the study assesses the sustainability of agricultural development in Russia by calculating the integrated index of five components: economic, innovative, social, ecological, and institutional. Also, the authors built a regression model that estimates the influence of innovation on the sustainability of agricultural development in Russia

Neurohumoral markers that predict the efficiency of pharmacologic therapy of depressive disorders

We present a comprehensive clinical and biological study of 46 patients with depressive disorder (F32-F33: depressive episode and recurrent depressive disorder) during pharmacotherapy. Neurohumoral factors (cortisol, brain-derived neurotrophic factor, serotonin, DHEA and its sulfated form) were determined in serum by ELISA. The severity of the current depressive episode was evaluated using the 17-point Hamilton Depression Rating Scale (HDRS-17); the pharmacotherapy efficacy was evaluated using the scale of the Clinical Global Impression (CGI Scale). We showed that before prescription of pharmacotherapy peripheral blood neurohumoral markers that characterize the state of stress-realizing and stress-limiting systems of the body may be considered as biological predictors of the effective pharmacotherapy of a current depressive episode and used as additional paraclinical examination methods. At higher concentrations of cortisol and serotonin associated with a decrease in the content of neurosteroid dehydroepiandrosterone, the high efficiency of the pharmacotherapy of depressive episode is predicted

Metallicity Effect on LMXB Formation in Globular Clusters

We present comprehensive observational results of the metallicity effect on the fraction of globular clusters (GC) that contain low-mass X-ray binaries (LMXB), by utilizing all available data obtained with Chandra for LMXBs and HST ACS for GCs. Our primary sample consists of old elliptical galaxies selected from the ACS Virgo and Fornax surveys. To improve statistics at both the lowest and highest X-ray luminosity, we also use previously reported results from other galaxies. It is well known that the LMXB fraction is considerably higher in red, metal-rich, than in blue, metal-poor GCs. In this paper, we test whether this metallicity effect is X-ray luminosity-dependent, and find that the effect holds uniformly in a wide luminosity range. This result is statistically significant (at >= 3 sigma) in LMXBs with luminosities in the range LX = 2 x 10^37 - 5 x 10^38 erg s-1, where the ratio of LMXB fractions in metal-rich to metal-poor GCs is R = 3.4 +- 0.5. A similar ratio is also found at lower (down to 10^36 erg s-1) and higher luminosities (up to the ULX regime), but with less significance (~2 sigma confidence). Because different types of LMXBs dominate in different luminosities, our finding requires a new explanation for the metallicity effect in dynamically formed LMXBs. We confirm that the metallicity effect is not affected by other factors such as stellar age, GC mass, stellar encounter rate, and galacto-centric distance.Comment: 21 pages, 5 figures, accepted in Ap

Yang-Mills instantons and dyons on homogeneous G_2-manifolds

We consider Lie G-valued Yang-Mills fields on the space R x G/H, where G/H is a compact nearly K"ahler six-dimensional homogeneous space, and the manifold R x G/H carries a G_2-structure. After imposing a general G-invariance condition, Yang-Mills theory with torsion on R x G/H is reduced to Newtonian mechanics of a particle moving in R^6, R^4 or R^2 under the influence of an inverted double-well-type potential for the cases G/H = SU(3)/U(1)xU(1), Sp(2)/Sp(1)xU(1) or G_2/SU(3), respectively. We analyze all critical points and present analytical and numerical kink- and bounce-type solutions, which yield G-invariant instanton configurations on those cosets. Periodic solutions on S^1 x G/H and dyons on iR x G/H are also given.Comment: 1+26 pages, 14 figures, 6 miniplot