316 research outputs found

    Objective appraisal of tolerance to ventriculography with various radiocontrast media (according to electronystagmography data)

    Get PDF
    The vestibulo oculomotor reflex (nystagmus) was recorded by means of electronystagmography in 33 neurosurgical patients in dynamics prior to and after ventriculography. For contrasting the ventricular system a water soluble medium (Conrey, dimer X or Amipak) was used in 18 patients and contrast mixtures of water soluble agents in combination with Myodil emulsion in 15. It was established that after ventriculography with water soluble media the trunk vestibular reactions in all types of nystagmus grew frequently and sharply and the vestibulovegetative reactions increased markedly

    Anomalous optical absorption in overdoped cuprates near the charge-ordering instability

    Full text link
    We propose an interpretation for the hump observed in the optical conductivity at or below a few hundreds of cm−1^{-1}, in overdoped cuprates like the electron-doped Nd_{2-x}Ce_xCuO_{4-y} at x\gtrsim 0.15 and the hole-doped Bi_2Sr_2CuO_6 and La_{2-x}Sr_xCuO_4. This interpretation is based on the direct excitation of charge collective modes, which become nearly critical in the proximity to a charge-ordering instability. The nearly critical character of these excitations entails a peculiar temperature dependence and a pseudo-scaling form of the lineshapes, which are in agreement with the experimental data.Comment: 5 pages, 3 figure

    c-axis transport and phenomenology of the pseudo-gap state in Bi2Sr2CaCu2O8+δBi_2Sr_2CaCu_2O_{8+\delta}

    Full text link
    We measure and analyze the resistivity of Bi2Sr2CaCu2O8+δBi_2Sr_2CaCu_2O_{8+\delta} crystals for different doping δ\delta. We obtain the fraction of carrier η(T,δ)=ng/nTOT\eta(T,\delta) = n_g/n_{TOT} that do not participate to the c-axis conductivity. All the curves η(T,δ)\eta(T,\delta) collapse onto a universal curve when plotted against a reduced temperature x=[T−Θ(δ)]/Δ∗(δ)x=[T-\Theta(\delta)]/\Delta^{*}(\delta). We find that at the superconducting transition ngn_g is doping independent. We also show that a magnetic field up to 14 T does not affect the degree of localization in the (a,b) planes but widens the temperature range of the x-scaling by suppressing the superconducting phase coherence.Comment: 11 pages, 5 figures, submitted to Phys.Rev.

    On a possibility of inelasticity partial coefficient K sub gamma determination in pi C and pi Pb interactions at 10 to the 14th power eV (experiment PAMIR 1)

    Get PDF
    The investigation of hadron-nuclear interactions in Pamir experiment is carried out by means of X-ray emulsion chambers of two types: carbon (C) and lead (Pb). While comparing the results from the chambers of both types it was found a discrepancy in n sub h and E sub h(1)R values. The observed discrepancy in C and Pb chambers is connected with the difference in values of effective coefficients of energy transfer to the soft component K sub eff for C and Pb chambers
    • …
    corecore