The power distribution of the eeg rhythm in verbal and spatial solving problems

The work is devoted to the study of the electrical activity of the cerebral cortex in students during verbal, image and spatial cognitive tasks. 35 students (17 men and 18 women) aged 18 to 25 years participated in the experiment. Three types of tasks were presented during the experiment. EEG was recorded while solving tasks. EEG spectral power in the implementation of various types of cognitive activity was analyzed. Multiple zonal differences of theta and alpha1 power were found between different cognitive states, including background with open eyes.Работа посвящена исследованию электрической активности коры головного мозга у студентов при решении вербальных, образных и пространственных задач. В эксперименте приняли участие 35 студентов вузов в возрасте от 18 до 25 лет. Испытуемым предъявлялись три типа задач, во время решения которых регистрировалась ЭЭГ. Проведен анализ спектральной мощности ЭЭГ при осуществлении различных типов когнитивной деятельности. Выявлены множественные зональные различия мощностей тета-ритма и альфа1-ритма между разными когнитивными состояниями, включая фоновое с открытыми глазами

The K^- \alpha scattering length and the reaction dd \to \alpha K^+ K^-

We present predictions for the the K^- \alpha scattering length obtained within the framework of the multiple scattering approach. Evaluating the pole position of the K^- \alpha scattering amplitude within the zero range approximation, we find a loosely bound K^- \alpha state with a binding energy of E_R = -2 ... -7 MeV and a width \Gamma_R = 11 ... 18 MeV. We propose to measure the K^- \alpha scattering length through the final state interaction between the \alpha and K^- meson produced in the reaction dd \to \alpha K^+ K^-. It is found that the K^-\alpha invariant mass distribution from this reaction at energies near the threshold provides a new tool to determine the s-wave K^- \alpha scattering length.Comment: 6 pages, 3 PS figure

Behaviour of the Blazar CTA 102 during two giant outbursts

Blazar CTA 102 underwent exceptional optical and high-energy outbursts in 2012 and 2016-2017. We analyze its behaviour during these events, focusing on polarimetry as a tool that allows us to trace changes in the physical conditions and geometric configuration of the emission source close to the central black hole. We also use Fermi gamma-ray data in conjunction with optical photometry in an effort to localize the origin of the outbursts.AST-1615796 - Boston Universit

Near-threshold production of a0(980)a_0(980)-mesons in πN\pi N and NN collisions and a0/f0a_0/f_0-mixing

We consider near-threshold $a_0(980)$-meson production in $\pi N$ and $NN$ collisions. An effective Lagrangian approach with one-pion exchange is applied to analyze different contributions to the cross section for different isospin channels. The Reggeon exchange mechanism is also evaluated for comparison. The results from $\pi N$ reactions are used to calculate the contribution of the $a_0$ meson to the cross sections and invariant $K \bar K$ mass distributions of the reactions $pp\to pn K^+\bar K^0$ and $pp\to pp K^+K^-$. It is found that the experimental observation of $a_0^+$ mesons in the reaction $pp\to pn K^+\bar K^0$ is much more promising than the observation of $a_0^0$ mesons in the reaction $pp\to pp K^+K^-$. Effects of isospin violation in the reactions $pN \to d a_0$, $pd \to \mathrm{^3He/^3H} a_0$, and $dd \to \mathrm{^4He} a_0$, which are induced by $a_0(980)$--$f_0(980)$ mixing, are also analyzed.Comment: 43 pages, including 16 eps figures, to be bublished in Phys. Atom. Nucl. (Yad. Fiz.) vol. 65, No. 11 (2002

Aspects of a0-f0 mixing in the reaction pn->da0

Some aspects of a0-f0 mixing effects in the reaction ${\vec p} n\to da^0_0$ with perpendicular polarized proton beam are discussed. An angular--asymmetry parameter $A$ is defined to study those effects. It is shown that, for energies close to the production threshold, the angular--asymmetry parameter $A(\theta, \phi)$ is proportional to the a0-f0 mixing amplitude for arbitrary polar and azimuthal angles $\theta$ and $\phi$ of the outgoing $a_0$ meson. This statement is also valid for arbitrary energies, but then only at polar angles $\theta=0^0$ and $\theta=90^0$. The mass dependence of the differential cross section $d\sigma/dm_{\pi^0\eta}$ in the reaction $pn\to d\pi^0\eta$ in the presence of \mix mixing is also discussed.Comment: 17 pages, 3 Figure

Indication of asymptotic scaling in the reactions dd→p3dd\to p^3H, dd→n3dd\to n^3He and dp→dpdp\to dp

It is shown that the differential cross sections of the reactions $dd\to ^3He n$ and $dd\to ^3H p$ measured at c.m.s.scattering angle$\theta_{cm}=60^\circ$ in the interval of the deuteron beam energy 0.5 - 1.2 GeV demonstrate the scaling behaviour,$d\sigma/d t\sim s^{-22}$, which follows from constituent quark counting rules. It is found also that the differential cross section of the elastic $dp\to dp$ scattering at $\theta_{cm}=125^\circ-135^\circ$ follows the scaling regime $\sim s^{-16}$ at beam energies 0.5 - 5 GeV. These data are parameterized here using the Reggeon exchange.Comment: 6 pages, Latex, 2 eps figures; final version accepted by Pis'ma v ZHETF, corrected and completed reference

Production of a0a_0-mesons in pp and pn reactions

We investigate the cross section for the reaction $NN \to NNa_0$ near threshold and at medium energies. An effective Lagrangian approach with one-pion exchange is applied to analyze different contributions to the cross section for different isospin channels. The Reggeon exchange mechanism is also considered. The results are used to calculate the contribution of the $a_0$ meson to the cross sections and invariant $K \bar K$ mass distributions of the reactions $pp\to pn K^+\bar K^0$ and $pp\to pp K^+K^-$. It is found that the experimental observation of $a_0^+$ mesons in the reaction $pp\to pn K^+\bar K^0$ is much more promising than the observation of $a_0^0$ mesons in the reaction $pp\to pp K^+K^-$.Comment: 26 pages, including 11 eps figures, to be bublished in J. Phys.

A multi-wavelength polarimetric study of the blazar CTA 102 during a Gamma-ray flare in 2012

We perform a multi-wavelength polarimetric study of the quasar CTA 102 during an extraordinarily bright $\gamma$-ray outburst detected by the {\it Fermi} Large Area Telescope in September-October 2012 when the source reached a flux of F$_{>100~\mathrm{MeV}} =5.2\pm0.4\times10^{-6}$ photons cm$^{-2}$ s$^{-1}$. At the same time the source displayed an unprecedented optical and NIR outburst. We study the evolution of the parsec scale jet with ultra-high angular resolution through a sequence of 80 total and polarized intensity Very Long Baseline Array images at 43 GHz, covering the observing period from June 2007 to June 2014. We find that the $\gamma$-ray outburst is coincident with flares at all the other frequencies and is related to the passage of a new superluminal knot through the radio core. The powerful $\gamma$-ray emission is associated with a change in direction of the jet, which became oriented more closely to our line of sight ($\theta\sim$1.2$^{\circ}$) during the ejection of the knot and the $\gamma$-ray outburst. During the flare, the optical polarized emission displays intra-day variability and a clear clockwise rotation of EVPAs, which we associate with the path followed by the knot as it moves along helical magnetic field lines, although a random walk of the EVPA caused by a turbulent magnetic field cannot be ruled out. We locate the $\gamma$-ray outburst a short distance downstream of the radio core, parsecs from the black hole. This suggests that synchrotron self-Compton scattering of near-infrared to ultraviolet photons is the probable mechanism for the $\gamma$-ray production.Comment: Accepted for publication in The Astrophysical Journa

KKbar photoproduction from protons

We study the contribution of the Drell mechanism driven by K^+ and K^- exchange to the reaction gamma N -> KKbar N. Our calculation implements the full KN and KbarN reaction amplitudes in the form of partial wave amplitudes taken from a meson-exchange model (KN) and a partial wave analysis (KbarN), respectively. Comparing our results to data of the LAMP2 collaboration we observe that the Drell mechanism alone cannot describe the large Lambda(1520) photoproduction rate observed experimentally. We argue that the discrepancy could be due to significant contributions from K*-meson exchange with subsequent excitation of the Lambda(1520) resonance. After adding such contributions to our model a good agreement of the LAMP2 experiment is achieved. When applying the same model to the recent SAPHIR data we find an excellent description of the K^+p spectrum and can determine the parameters of the Lambda(1600) P01 resonance, M_R = 1617 +/- 2 MeV and Gamma_R = 117 +/- 4 MeV, from the K^-p mass distribution.Comment: updated version, analysis of new CLAS data included, 11 pages, 11 figure

Special approach to the analysis and evaluation of the composition of red blood in athletes (on the example of rowing and canoeing)

The results of the analysis of red blood parameters in professional rowers showed that they have different mechanisms for the development of pre- and anemic conditions. This makes it necessary in each specific case to determine the prevailing of them, which requires an expansion of the set of recorded parameters