Maeda-Dadhich Solutions as Real Black Holes

A four-dimensional static Schwarzschild-like solution obtained in [3]-[6] in the frames of the Einstein-Gauss-Bonnet gravity at the Kaluza-Klein split is analyzed. The matter in these solutions is created by auxiliary dimensions. The main goal of our work is to study physically sensible characteristics, which could be observable. Study of the perturbed equations demonstrates their stability under linear perturbations. The specific combinations of the parameters, permitting to construct black hole-like objects with one or two horizons or naked singularities are determined. Stable orbits of test particles around these black holes are presented. We show the exotic thermodynamical properties of the solution, when the Hawking evaporation law has the behavior opposite to usual one in General Relativity

Nonlinearity of vacuum reggeons and exclusive diffractive production of vector mesons at HERA

The processes of exclusive photo- and electroproduction of vector mesons $\rho^0$(770), $\phi$(1020) and $J/\psi$(3096) at collision energies $30 GeV<W<300 GeV$ and transferred momenta squared $0<-t<2 GeV^2$ are considered in the framework of a phenomenological Regge-eikonal scheme with nonlinear Regge trajectories in which their QCD asymptotic behavior is taken into account explicitly. By comparison of available experimental data from ZEUS and H1 Collaborations with the model predictions it is demonstrated that corresponding angular distributions and integrated cross-sections in the above-mentioned kinematical range can be quantitatively described with use of two $C$-even vacuum Regge trajectories. These are the "soft" pomeron dominating the high energy reactions without a hard scale and the "hard" pomeron giving an essential contribution to photo- and electroproduction of heavy vector mesons and deeply virtual electroproduction of light vector mesons.Comment: 25 pages, 12 figure

Controlling integrability in a quasi-1D atom-dimer mixture

We analytically study the atom-dimer scattering problem in the near-integrable limit when the oscillator length l_0 of the transverse confinement is smaller than the dimer size, ~l_0^2/|a|, where a<0 is the interatomic scattering length. The leading contributions to the atom-diatom reflection and break-up probabilities are proportional to a^6 in the bosonic case and to a^8 for the up-(up-down) scattering in a two-component fermionic mixture. We show that by tuning a and l_0 one can control the "degree of integrability" in a quasi-1D atom-dimer mixture in an extremely wide range leaving thermodynamic quantities unchanged. We find that the relaxation to deeply bound states in the fermionic (bosonic) case is slower (faster) than transitions between different Bethe ansatz states. We propose a realistic experiment for detailed studies of the crossover from integrable to nonintegrable dynamics.Comment: 12 pages, 1 figur

Active shielding of magnetic field with circular space-time characteristic

Aim. The synthesis of two degree of freedom robust two circuit system of active shielding of magnetic field with circular spacetime characteristic, generated by overhead power lines with "triangle" type of phase conductors arrangements for reducing the magnetic flux density to the sanitary standards level and to reducing the sensitivity of the system to plant parameters uncertainty. Methodology. The synthesis is based on the multi-criteria game decision, in which the payoff vector is calculated on the basis of the Maxwell equations quasi-stationary approximation solutions. The game decision is based on the stochastic particles multiswarm optimization algorithms. The initial parameters for the synthesis by system of active shielding are the location of the overhead power lines with respect to the shielding space, geometry and number of shielding coils, operating currents, as well as the size of the shielding space and magnetic flux density normative value, which should be achieved as a result of shielding. The objective of the synthesis is to determine their number, configuration, spatial arrangementand and shielding coils currents, setting algorithm of the control systems as well as the resulting of the magnetic flux density value at the shielding space. Results. Computer simulation and field experimental research results of two degree of freedom robust two circuit system of active shielding of magnetic field, generated by overhead power lines with «triangle» type of phase conductors arrangements are given. The possibility of initial magnetic flux density level reducing and system sensitivity reducing to the plant parameters uncertainty is shown. Originality. For the first time the synthesis, theoretical and experimental research of two degree of freedom robust two -circuit t system of active shielding of magnetic field generated by single-circuit overhead power line with phase conductors triangular arrangements carried out. Practical value. Practical recommendations from the point of view of the practical implementation on reasonable choice of the spatial arrangement of two shielding coils of robust two -circuit system of active shielding of the magnetic field with circular space-time characteristic generated by single-circuit overhead power line with phase conductors triangular arrangements are given.Цель. Синтез комбинированной робастной двухконтурной системы активного экранирования магнитного поля с круговой пространственно-временной характеристикой, генерируемого одноконтурной воздушной линией электропередачи с треугольным подвесом проводов для снижения индукции магнитного поля до уровня санитарных норм и для снижения чувствительности системы к неопределенности параметров объекта управления. Методология. Синтез основан на решении многокритериальной стохастической игры, в которой векторный выигрыш вычисляется на основании решений уравнений Максвелла в квазистационарном приближении. Решение игры находится на основе алгоритмов стохастической мультиагентной оптимизации мультироем частиц. Исходными параметрами для синтеза системы активного экранирования являются расположение высоковольтной линий электропередачи по отношению к экранируемому пространству, геометрические размеры, количество проводов и рабочие токи линии электропередачи, а также размеры экранируемого пространства и нормативное значение индукции магнитного поля, которое должно быть достигнуто в результате экранирования. Задачей синтеза является определение количества, конфигурации, пространственного расположения и токов экранирующих обмоток, алгоритма работы системы управления, а также результирующего значения индукции магнитного поля в экранируемом пространстве. Результаты. Приводятся результаты теоретических и полевых экспериментальных исследований комбинированной робастной двухконтурной системы активного экранирования магнитного поля, генерируемого воздушной линией электропередачи с треугольным подвесом проводов. Показана возможность снижения уровня индукции исходного магнитного поля внутри экранируемого пространства и снижения чувствительности системы к неопределенностям параметров объекта управления. Оригинальность. Впервые проведены синтез, теоретические и экспериментальные исследования комбинированной робастной двухконтурной системы активного экранирования магнитного поля, генерируемого одноконтурной воздушной линией электропередачи с треугольным подвесом проводов. Практическая ценность. Приводятся практические рекомендации по обоснованному выбору с точки зрения практической реализации пространственного расположения двух экранирующих обмоток двухконтурной робастной системы активного экранирования магнитного поля с круговой пространственно-временной характеристикой, создаваемого одноконтурной воздушной линией электропередачи с треугольным подвесом проводов

A note on the Deser-Tekin charges

Perturbed equations for an arbitrary metric theory of gravity in $D$ dimensions are constructed in the vacuum of this theory. The nonlinear part together with matter fields are a source for the linear part and are treated as a total energy-momentum tensor. A generalized family of conserved currents expressed through divergences of anti-symmetrical tensor densities (superpotentials) linear in perturbations is constructed. The new family generalizes the Deser and Tekin currents and superpotentials in quadratic curvature gravity theories generating Killing charges in dS and AdS vacua. As an example, the mass of the $D$-dimensional Schwarzschild black hole in an effective AdS spacetime (a solution in the Einstein-Gauss-Bonnet theory) is examined.Comment: LATEX, 7 pages, no figure

Genotoxic effects of copper sulfate in rabbits

This study was carried out to determine the genotoxic effects of oral application of CuSO4 in rabbits by the chromosome aberration (CA) and sister chromatid exchange (SCE) tests. Ten male New Zealand rabbits (5 months old, weighing 3.5-4.0 kg) were allocated into two groups. The first group received CuSO4 (5H2O) in drinking water for 6 consecutive days. The second group was used as a control. On the 7th day, blood samples were taken from the ear marginal vein and the SCE and CA tests in peripheral lymphocytes were used as genotoxicity and mutagenicity endpoints, respectively. Results showed a significant increase in the frequencies of the aberrant cells (7.4±0.24, P<0.001) and CA (chromatid fragments 3.2±0.37, chromosome fragments 4.2±0.37, P<0.001), and total aberrations (7.4±0.24, P<0.001) after the treatment with CuSO4 when compared with the control group. The level of SCE per cell in the CuSO4-treated rabbits (9.66±0.062) was significantly higher than in rabbits from the control group. These findings show that copper exhibits a genotoxic and mutagenic potential in rabbits

Mass Dependence of Ultracold Three-Body Collision Rates

We show that many aspects of ultracold three-body collisions can be controlled by choosing the mass ratio between the collision partners. In the ultracold regime, the scattering length dependence of the three-body rates can be substantially modified from the equal mass results. We demonstrate that the only non-trivial mass dependence is due solely to Efimov physics. We have determined the mass dependence of the three-body collision rates for all heteronuclear systems relevant for two-component atomic gases with resonant s-wave interspecies interactions, which includes only three-body systems with two identical bosons or two identical fermions

First result with AMBER+FINITO on the VLTI: The high-precision angular diameter of V3879 Sgr

Our goal is to demonstrate the potential of the interferometric AMBER instrument linked with the Very Large Telescope Interferometer (VLTI) fringe-tracking facility FINITO to derive high-precision stellar diameters. We use commissioning data obtained on the bright single star V3879 Sgr. Locking the interferometric fringes with FINITO allows us to record very low contrast fringes on the AMBER camera. By fitting the amplitude of these fringes, we measure the diameter of the target in three directions simultaneously with an accuracy of 25 micro-arcseconds. We showed that V3879 Sgr has a round photosphere down to a sub-percent level. We quickly reached this level of accuracy because the technique used is independent from absolute calibration (at least for baselines that fully span the visibility null). We briefly discuss the potential biases found at this level of precision. The proposed AMBER+FINITO instrumental setup opens several perspectives for the VLTI in the field of stellar astrophysics, like measuring with high accuracy the oblateness of fast rotating stars or detecting atmospheric starspots