626 research outputs found

    The course of experimental staphylococcus infection in albino mice during action of certain factors of space flight

    Get PDF
    A study was made of the effect of certain factors of space flight, acceleration and hypokinesia, on the course of experimental staphylococcus infection in mice. Combined action of hypokinesia and acceleration caused a marked depression of the phagocytic activity of leukocytes and formation of a considerable amount of alpha toxin

    Transfer in Implicit Learning

    Get PDF
    The article describes the research, the aim of which is to discover the effect of transfer of the implicit knowledge of artificial grammar to solving of sensory-motor tasks. The article considers the role of implicit knowledge in actual cognitive activity. Forty volunteers took part in the experiment. Participants of the experiment wereimplicitly taught the rule of artificial grammar. At the control phase, the assignment consisted of solving the sensory-motor problem – to react to the appearance of the green or yellow circle by pressing a certain key. In the experimental group, the grammatical line always appeared before the green-colored circle was presented, and the ungrammatical line appeared before the yellow-colored circle. In the control group the color of the circle didn’t depend on the grammaticality of the line. As a result, we established the considerable reduction in the reaction time in the experimental group. Thus, the transfer of the implicitly learned knowledge of artificial grammar leads to enhancement of efficiency of sensory-motor activity. The implicit rule of artificialgrammar has acquired role of prime-stimulation. Keywords: implicit knowledge, implicit learning, artificial grammar learning, sensorymotor activity, transfer effect, primin

    Nitric Oxide Has a Concentration-Dependent Effect on the Cell Cycle Acting via EIN2 in Arabidopsis thaliana Cultured Cells

    Get PDF
    Ethylene is known to influence the cell cycle (CC) via poorly characterized roles whilst nitric oxide (NO) has well-established roles in the animal CC but analogous role(s) have not been reported for plants. As NO and ethylene signaling events often interact we examined their role in CC in cultured cells derived from Arabidopsis thaliana wild-type (Col-0) plants and from ethylene-insensitive mutant ein2-1 plants. Both NO and ethylene were produced mainly during the first 5 days of the sub-cultivation period corresponding to the period of active cell division. However, in ein2-1 cells, ethylene generation was significantly reduced while NO levels were increased. With application of a range of concentrations of the NO donor, sodium nitroprusside (SNP) (between 20 and 500 μM) ethylene production was significantly diminished in Col-0 but unchanged in ein2-1 cells. Flow cytometry assays showed that in Col-0 cells treatments with 5 and 10 μM SNP concentrations led to an increase in S-phase cell number indicating the stimulation of G1/S transition. However, at ≥20 μM SNP CC progression was restrained at G1/S transition. In the mutant ein2-1 strain, the index of S-phase cells was not altered at 5–10 μM SNP but decreased dramatically at higher SNP concentrations. Concomitantly, 5 μM SNP induced transcription of genes encoding CDKA;1 and CYCD3;1 in Col-0 cells whereas transcription of CDKs and CYCs were not significantly altered in ein2-1 cells at any SNP concentrations examined. Hence, it is appears that EIN2 is required for full responses at each SNP concentration. In ein2-1 cells, greater amounts of NO, reactive oxygen species, and the tyrosine-nitrating peroxynitrite radical were detected, possibly indicating NO-dependent post-translational protein modifications which could stop CC. Thus, we suggest that in Arabidopsis cultured cells NO affects CC progression as a concentration-dependent modulator with a dependency on EIN2 for both ethylene production and a NO/ethylene regulatory function

    Limitations on the superposition principle: superselection rules in non-relativistic quantum mechanics

    Get PDF
    The superposition principle is a very basic ingredient of quantum theory. What may come as a surprise to many students, and even to many practitioners of the quantum craft, is tha superposition has limitations imposed by certain requirements of the theory. The discussion of such limitations arising from the so-called superselection rules is the main purpose of this paper. Some of their principal consequences are also discussed. The univalence, mass and particle number superselection rules of non-relativistic quantum mechanics are also derived using rather simple methods.Comment: 22 pages, no figure

    Quantum oscillations in the linear chain of coupled orbits: the organic metal with two cation layers theta-(ET)(4)CoBr(4)(C(6)H(4)Cl(2))

    Full text link
    Analytical formulae for de Haas-van Alphen (dHvA) oscillations in linear chain of coupled two-dimensional (2D) orbits (Pippard's model) are derived systematically taking into account the chemical potential oscillations in magnetic field. Although corrective terms are observed, basic (alpha) and magnetic breakdown-induced (beta and 2beta - alpha) orbits can be accounted for by the Lifshits-Kosevich (LK) and Falicov-Stachowiak semiclassical models in the explored field and temperature ranges. In contrast, the 'forbidden orbit' beta - alpha amplitude is described by a non-LK equation involving a product of two classical orbit amplitudes. Furthermore, strongly non-monotonic field and temperature dependence may be observed for the second harmonics of basic frequencies such as 2alpha and the magnetic breakdown orbit beta + alpha, depending on the value of the spin damping factors. These features are in agreement with the dHvA oscillation spectra of the strongly 2D organic metal theta- theta-(ET)(4)CoBr(4)(C(6)H(4)Cl(2)).Comment: to be published in Europhysics Letters (2012

    THE PECULIARITY OF THE PROPAGATION OF LIGHT BULLETS IN AN ANISOTROPIC PHOTONIC CRYSTAL DURING TUNNEL IONIZATION

    Full text link
    This paper presents the results of numerical simulation of three-dimensional light bullets that propagate in the medium of an array of semiconductor carbon nanotubes, which has a spatially modulated refractive index, taking into account the external pumping field and tunnel ionization

    Relative luminosity measurement of the LHC with the ATLAS forward calorimeter

    Full text link
    In this paper it is shown that a measurement of the relative luminosity changes at the LHC may be obtained by analysing the currents drawn from the high voltage power supplies of the electromagnetic section of the forward calorimeter of the ATLAS detector. The method was verified with a reproduction of a small section of the ATLAS forward calorimeter using proton beams of known beam energies and variable intensities at the U-70 accelerator at IHEP in Protvino, Russia. The experimental setup and the data taking during a test beam run in April 2008 are described in detail. A comparison of the measured high voltage currents with reference measurements from beam intensity monitors shows a linear dependence on the beam intensity. The non-linearities are measured to be less than 0.5 % combining statistical and systematic uncertainties.Comment: 16 page

    Spectacular enhancement of the thermal and photochemical stability of mapbi3 perovskite films using functionalized tetraazaadamantane as a molecular modifier

    Full text link
    Perovskite solar cells represent a highly promising third-generation photovoltaic tech-nology. However, their practical implementation is hindered by low device operational stability, mostly related to facile degradation of the absorber materials under exposure to light and elevated temperatures. Improving the intrinsic stability of complex lead halides is a big scientific challenge, which might be addressed using various “molecular modifiers”. These modifiers are usually rep-resented by some additives undergoing strong interactions with the perovskite absorber material, resulting in enhanced solar cell efficiency and/or operational stability. Herein, we present a deriva-tive of 1,4,6,10-tetraazaadamantane, NAdCl, as a promising molecular modifier for lead halide perovskites. NAdCl spectacularly improved both the thermal and photochemical stability of methy-lammonium lead iodide (MAPbI3 ) films and, most importantly, prevented the formation of metallic lead Pb0 as a photolysis product. NAdCl improves the electronic quality of perovskite films by healing the traps for charge carriers. Furthermore, it strongly interacts with the perovskite framework and most likely stabilizes undercoordinated Pb2+ ions, which are responsible for Pb0 formation under light exposure. The obtained results feature 1,4,6,10-tetraazaadamantane derivatives as highly promising molecular modifiers that might help to improve the operational lifetime of perovskite solar cells and facilitate the practical implementation of this photovoltaic technology. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.This work was supported by Russian Science Foundation (project No. 19-73-30020). The XPS measurements were supported by the Ministry of Education and Science of the Russian Federation (project FEUZ-2020-0060), Theme ‘Electron’, no. AAAA-A18-118020190098-5 and Russian Foundation for Basic Research (project No. 21-52-52002)

    Inhomogeneous States in a Small Magnetic Disk with Single-Ion Surface Anisotropy

    Full text link
    We investigate analytically and numerically the ground and metastable states for easy-plane Heisenberg magnets with single-ion surface anisotropy and disk geometry. The configurations with two half-vortices at the opposite points of the border are shown to be preferable for strong anisotropy. We propose a simple analytical description of the spin configurations for all values of a surface anisotropy. The effects of lattice pinning leads to appearance of a set of metastable configurations.Comment: 10 pages, 7 figures; submitted to Phys. Rev.
    corecore