2,109 research outputs found

    Cough. The place of herbal medicine in treatment

    Get PDF
    Cough is one of the auxiliary mechanisms for cleaning the airways from mucus, foreign particles, microorganisms. The physiological cough reflex allows the mechanism of airway cleansing, provided that mucociliary clearance works sufficiently. However, sometimes the cough loses its protective function, becomes persistent, and impairs the quality of life of the patient. In this regard, in the treatment of cough, attention is paid to both secretomotor and secretolytic therapy. Medicinal plants are among the drugs with such properties. Numerous group of drugs containing herbal components has a reflex action, which allows coping most effectively with cough in the initial stages of diseases accompanied by respiratory symptoms. The most common among them and widely used are plantain leaf, coltsfoot leaf, thermopsis herb, ipecacuanha root, marshmallow root, licorice root, anise fruit, thyme (thyme) herb extract, ivy leaf extract. A well-known drug, the active ingredient of which is ivy leaf extract. Its mechanism of action consists in increasing the production of surfactant and increasing the number of β2-adrenoreceptors on the surface of alveolar cells of the bronchial tree, to which ivy active substance α-hederin is attached, which has a bronchospasmodic and expectorant action. Numerous clinical studies have proven a high efficacy and safety of the product based on ivy leaf extract, which allows us to recommend it as the drug of choice for symptomatic cough therapy in both children and adults during acute respiratory infections

    Survey of charge symmetry breaking operators for dd -> alpha pi0

    Full text link
    The charge-symmetry-breaking amplitudes for the recently observed d d -> alpha pi0 reaction are investigated. Chiral perturbation theory is used to classify and identify the leading-order terms. Specific forms of the related one- and two-body tree level diagrams are derived. As a first step toward a full calculation, a few tree-level two-body diagrams are evaluated at each considered order, using a simplified set of d and alpha wave functions and a plane-wave approximation for the initial dd state. The leading-order pion-exchange term is shown to be suppressed in this model because of poor overlap of the initial and final states. The higher-order one-body and short-range (heavy-meson-exchange) amplitudes provide better matching between the initial and final states and therefore contribute significantly and coherently to the cross section. The consequences this might have for a full calculation, with realistic wave functions and a more complete set of amplitudes, are discussed.Comment: REVTeX 4, 35 pages, 8 eps figures, submitted to PR

    Impact of saturation on spin effects in proton-proton scattering

    Full text link
    For pomerons described by a sum of two simple-pole terms, a soft and a hard pomeron, the unitarity bounds from saturation in impact-parameter space are examined. We consider the effect of these bounds on observables linked with polarisation, such as the analyzing power in elastic proton-proton scattering, for LHC energies. We obtain the s and t dependence of the Coulomb-nuclear interference at small momentum transfer, and show that the effect of the hard pomeron may be observed at the LHC.Comment: 8 pages, 2 figures, presented by O.V.S. at the Advanced Studies Institute "Symetries and Spin" (SPIN-Praha-2004), Prague, July 5 - July 10, 200

    Z2_2 topology and superconductivity from symmetry lowering of a 3D Dirac Metal Au2_2Pb

    Full text link
    3D Dirac semi-metals (DSMs) are materials that have massless Dirac electrons and exhibit exotic physical properties It has been suggested that structurally distorting a DSM can create a Topological Insulator (TI), but this has not yet been experimentally verified. Furthermore, quasiparticle excitations known as Majorana Fermions have been theoretically proposed to exist in materials that exhibit superconductivity and topological surface states. Here we show that the cubic Laves phase Au2_2Pb has a bulk Dirac cone above 100 K that gaps out upon cooling at a structural phase transition to create a topologically non trivial phase that superconducts below 1.2 K. The nontrivial Z2_2 = -1 invariant in the low temperature phase indicates that Au2_2Pb in its superconducting state must have topological surface states. These characteristics make Au2_2Pb a unique platform for studying the transition between bulk Dirac electrons and topological surface states as well as studying the interaction of superconductivity with topological surface states

    Nucleon Polarizibilities for Virtual Photons

    Get PDF
    We generalize the sum rules for the nucleon electric plus magnetic polarizability Σ=α+β\Sigma=\alpha+\beta and for the nucleon spin-polarizability γ\gamma, to virtual photons with Q2>0Q^2>0. The dominant low energy cross sections are represented in our calculation by one-pion-loop graphs of relativistic baryon chiral perturbation theory and the Δ(1232)\Delta(1232)-resonance excitation. For the proton we find good agreement of the calculated Σp(Q2)\Sigma_p(Q^2) with empirical values obtained from integrating up electroproduction data for Q2<0.4GeV2Q^2<0.4 GeV^2. The proton spin-polarizability γp(Q2)\gamma_p(Q^2) switches sign around Q2=0.4GeV2Q^2= 0.4 GeV^2 and it joins smoothly the "partonic" curve, extracted from polarized deep-inelastic scattering, around Q2=0.7GeV2Q^2=0.7 GeV^2. For the neutron our predictions of Σn(Q2)\Sigma_n(Q^2) and γn(Q2)\gamma_n(Q^2) agree reasonably well at Q2=0Q^2=0 with existing determinations. Upcoming (polarized) electroproduction experiments will be able to test the generalized polarizability sum rules investigated here.Comment: 12 pages, 5 figures, submittes to Nuclear Physics

    The effects of the small t properties of hadronic scattering amplitude on the determination its real part

    Full text link
    Taking into account the different forms of the Coulomb-hadron interference phase and the possible spin-flip contribution the new analysis of the experimental data of the proton-antiproton elastic scattering at 3.8<pL<6.0 3.8 < p_L <6.0 \ GeV/c and small momentum transfer is carried out. It is shown that the size of the spin-flip amplitude can be determined from the form of the differential cross sections at small tt, and the deviation of ρ(s,t)\rho(s,t) obtained from the examined experimental data of the ppˉp\bar{p} scattering from the analysis \cite{Kroll}, based on the dispersion relations, is conserved in all xamined assumptions. The analysis of the proton-proton elastic scattering at 9<pL<70 9 < p_L < 70 \ GeV/c also shows the impact of the examined effects on the form of the differential cross sections.Comment: 13 pages, 3 figure

    Mechanisms for High-frequency QPOs in Neutron Star and Black Hole Binaries

    Get PDF
    We explain the millisecond variability detected by Rossi X-ray Timing Explorer (RXTE) in the X-ray emission from a number of low mass X-ray binary systems (Sco X-1, 4U1728-34, 4U1608-522, 4U1636-536, 4U0614+091, 4U1735-44, 4U1820-30, GX5-1 and etc) in terms of dynamics of the centrifugal barrier, a hot boundary region surrounding a neutron star. We demonstrate that this region may experience the relaxation oscillations, and that the displacements of a gas element both in radial and vertical directions occur at the same main frequency, of order of the local Keplerian frequency. We show the importance of the effect of a splitting of the main frequency produced by the Coriolis force in a rotating disk for the interpretation of a spacing between the QPO peaks. We estimate a magnitude of the splitting effect and present a simple formula for the whole spectrum of the split frequencies. It is interesting that the first three lowest-order overtones fall in the range of 200-1200 Hz and match the kHz-QPO frequencies observed by RXTE. Similar phenomena should also occur in Black Hole (BH) systems, but, since the QPO frequency is inversely proportional to the mass of a compact object, the frequency of the centrifugal-barrier oscillations in the BH systems should be a factor of 5-10 lower than that for the NS systems. The X-ray spectrum formed in this region is a result of upscattering of a soft radiation (from a disk and a NS surface) off relatively hot electrons in the boundary layer. We also briefly discuss some alternative QPO models, including a possibility of acoustic oscillations in the boundary layer, the proper stellar rotation, and g-mode disk oscillations.Comment: The paper is coming out in the Astrophysical Journal in the 1st of May issue of 199

    Coulomb-hadron phase factor and spin phenomena in a wide region of transfer momenta

    Get PDF
    The Coulomb-hadron interference effects are examined at small and large tt. The methods for the definition of spin-dependent parts of hadron scattering amplitude are presented. The additional contributions to analyzing power ANA_N and the double spin correlation parameter ANNA_{NN} owing to the electromagnetic-hadron interference are determined in the diffraction dip domain of high-energy elastic hadron scattering.Comment: 9 pages, LaTeX, 4 figure
    corecore