On the hyperfine interaction in rare-earth Van Vleck paramagnets at high magnetic fields

An influence of high magnetic fields on hyperfine interaction in the rare-earth ions with non-magnetic ground state (Van Vleck ions) is theoretically investigated for the case of $Tm^{3+}$ ion in axial symmetrical crystal electric field (ethylsulphate crystal). It is shown that magnetic-field induced distortions of $4f$-electron shell lead to essential changes in hyperfine magnetic field at the nucleus. The proposed theoretical model is in agreement with recent experimental data.Comment: 4 pages, no figures, submitted to J. Phys. : Cond. Mat

Temperature dependence of the EPR linewidth of Yb3+ - ions in Y0.99Yb0.01Ba2Cu3OX compounds: Evidence for an anomaly near TC

Electron paramagnetic resonance experiments on doped Yb3+ ions in YBaCuO compounds with different oxygen contents have been made. We have observed the strong temperature dependence of the EPR linewidth in the all investigated samples caused by the Raman processes of spin-lattice relaxation. The spin-lattice relaxation rate anomaly revealed near TC in the superconducting species can be assigned to the phonon density spectrum changesComment: 10 pages, 4 figures Renewed versio

Temperature dependence of the EPR linewidth of Yb3+ ions in Y0.99Yb0.01Ba2Cu3OX (6 ≤ X ≤ 7) compounds: Evidence for an anomaly near the superconducting transition

Electron paramagnetic resonance experiments on doped Yb3+ ions in Y0.99Yb0.01Ba2Cu3OX (6 ≤ X ≤ 7) compounds with different oxygen contents have been made. We have observed a strong temperature dependence of the EPR linewidth in all the investigated samples caused by the Raman processes of spin-lattice relaxation. The spin-lattice relaxation rate anomaly revealed near TC in the superconducting species can be assigned to the phonon density spectrum changes. © 2005 IOP Publishing Ltd

Crystal electric field excitations in the non-fermy liquid compound YbRh 2Si 2

We have calculated the crystalline electric field (CEF) splitting of the energy levels of Yb 3+ (4f 13) in the clean Yb-based heavy fermion compound YbRh 2Si 2. The data of inelastic neutron scattering and electron spin resonance measurements in YbRh 2Si 2, together with relevant structural, thermodynamic, and magnetic properties, were used as input in the calculations of the possible CEF level scheme in this non-Fermi-liquid compound. Two possible sets of the CEF parameters with the Γ 6 or Γ 7 ground-state symmetry are discussed. © Springer Science+Business Media, LLC 2007

Classical and quantum dynamics of confined test particles in brane gravity

A model is constructed for the confinement of test particles moving on a brane. Within the classical framework of this theory, confining a test particle to the brane eliminates the effects of extra dimensions, rendering them undetectable. However, in the quantized version of the theory, the effects of the gauge fields and extrinsic curvature are pronounced and this might provide a hint for detecting them. As a consequence of confinement the mass of the test particle is shown to be quantized. The condition of stability against small perturbations along extra dimensions is also studied and its relation to dark matter is discussed.Comment: 15 pages, no figures, extended, references adde

Multidimensional Toda type systems

On the base of Lie algebraic and differential geometry methods, a wide class of multidimensional nonlinear systems is obtained, and the integration scheme for such equations is proposed.Comment: 29 pages, LaTeX fil

Organ-sparing treatment for primarily disseminated breast cancer with metachronous bilateral involvement

Systemic drug therapy remains first-line treatment for primarily disseminated breast cancer (BC). The problem in the use of local methods to treat BC patients with distant metastases has not been fully solved. The most of investigations presented in the modern literature suggest that patients show significantly better survivals after adjuvant systemic therapy with local exposure of a primary tumor, the main goal of which is its local monitoring. At the same time, the choice of optimal treatments and their sequence and combination remain to be explored. The paper describes a case of successful organ-sparing chemoradiation therapy for primarily disseminated BC with metachronous bilateral involvement

Theory of AC Josepson Effect in Superconducting Constrictions

We have developed a microscopic theory of ac Josephson effect in short ballistic superconducting constrictions with arbitrary electron transparency and in constrictions with diffusive electron transport. The theory is valid for arbitrary miscroscopic structure of the superconducting electrodes of the constriction. As applications of the theory we study smearing of the subgap current singularities by pair-breaking effects and also the structure of these singularities in the constrictions between the composite S/N electrodes with the proximity-induced gap in the normal layer.Comment: 11 pages, RevTex, 3 figures available on reques

Multidrug-resistance and presence of class 1 integrons in clinical isolates of Salmonella enterica serotype Enteritidis, circulating in Armenia

Abstract. The aim of this work was detection of class 1 integrons and their contribution to the antimicrobial resistance phenotypes in strains of   subspecies enterica serotype Enteritidis. S. Enteritidis strains (n = 29) were isolated from patients with salmonellosis at “Nork” Clinical Hospital of Infectious Diseases, Yerevan, Republic of Armenia. High prevalence of multi-drug resistance (MDR) phenotypes was revealed and isolates with MDR phenotypes which are rare in the S. Enteritidis serotype were observed. Class 1 integrons were detected in 27,6% of isolates, with the prevalence of a variable region of 1000 bp. Occurrence of the MDR phenotype was more frequent in integron-positive isolates compared to integron-negative isolates of S. Enteritidis. Further studies are necessary to reveal the genetic background of MDR phenotypes and to estimate the genetic kinship among the isolates. Our results suggest a rapid and large-scale penetration of antibiotic resistance genes into populations of S. Enteritidis, which complicates infection control. More rigorous regulations should be imposed on antibiotic use, together with a vigilant epidemiological surveillance, to prevent the emergence and spread of MDR S. Enteritidis