10,157 research outputs found

    Magnetic and electronic properties of M-Ba-Cu-O (M: Y, Er, Eu)

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    Various high-Tc superconductors of the La-(Ba,Sr)-Cu-O and the M-Ba-Cu-O systems with M = Y, Er, and Eu have been prepared by the solid-state reaction method. Single-phase samples with no additional diffraction peaks as verified by x-ray diffraction (XRD) measurements have been obtained. Measurements of the electrical resistivity and of the magnetization showed sharp superconducting transitions with a width of 1 K. The measurements of the magnetic susceptibility have been extended above room temperature up to 770 K. There is clear evidence for the formation of a magnetic moment in all M-Ba-Cu-O samples. Monochromated x-ray photoelectron spectroscopy (MXPS) valence band and x-ray photoelectron spectroscopy (XPS) core level spectra have been measured on various samples at room temperature and at liquid nitrogen temperatur

    Phylogenetic diversity of insecticolous fusaria inferred from multilocus DNA sequence data and their molecular identification via FUSARIUM-ID and Fusarium MLST

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    We constructed several multilocus DNA sequence datasets to assess the phylogenetic diversity of insecticolous fusaria, especially focusing on those housed at the Agricultural Research Service Collection of Entomopathogenic Fungi (ARSEF), and to aid molecular identifications of unknowns via the FUSARIUM-ID and Fusarium MLST online databases and analysis packages. Analyses of a 190-taxon, two-locus dataset, which included 159 isolates from insects, indicated that: (i) insect-associated fusaria were nested within 10 species complexes spanning the phylogenetic breadth of Fusarium, (ii) novel, putatively unnamed insecticolous species were nested within 8/10 species complexes and (iii) Latin binomials could be applied with confidence to only 18/58 phylogenetically distinct fusaria associated with pest insects. Phylogenetic analyses of an 82-taxon, three-locus dataset nearly fully resolved evolutionary relationships among the 10 clades containing insecticolous fusaria. Multilocus typing of isolates within four species complexes identified surprisingly high genetic diversity in that 63/65 of the fusaria typed represented newly discovered haplotypes. The DNA sequence data, together with corrected ABI sequence chromatograms and alignments, have been uploaded to the following websites dedicated to identifying fusaria: FUSARIUM-ID (http://isolate.fusariumdb.org) a

    Treatment of Advanced Emphysema with Emphysematous Lung Sealant (AeriSeal (R))

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    Background: This report summarizes initial tests of an emphysematous lung synthetic polymer sealant (ELS) designed to reduce lung volume in patients with advanced emphysema. Objectives: The primary study objective was to define a therapeutic strategy to optimize treatment safety and effectiveness. Methods: ELS therapy was administered bronchoscopically to 25 patients with heterogeneous emphysema in an open-label, noncontrolled study at 6 centers in Germany. Treatment was performed initially at 2-4 subsegments. After 12 weeks, patients were eligible for repeat therapy to a total of 6 sites. Safety and efficacy were assessed after 6 months. Responses were evaluated in terms of changes from baseline in lung physiology, functional capacity, and health-related quality of life. Follow-up is available for 21 of 25 patients. Results: Treatment was well tolerated. There were no treatment-related deaths (i.e. within 90 days of treatment), and an acceptable short-and long-term safety profile. Physiological and clinical benefits were observed at 24 weeks. Efficacy responses were better among Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage III patients {[}n = 14; change in residual volume/total lung capacity (Delta RV/TLC) = -7.4 +/- 10.3%; Delta forced expiratory volume in 1 s (Delta FEV(1)) = +15.9 +/- 22.6%; change in forced vital capacity (Delta FVC) = +24.1 +/- 22.7%; change in carbon monoxide lung diffusion capacity (Delta DLCO) = +19.3 +/- 34.8%; change in 6-min walk test (Delta 6MWD) = +28.7 +/- 59.6 m; change in Medical Research Council Dyspnea (Delta MRCD) score = -1.0 +/- 1.04 units; change in St. George's Respiratory Questionnaire (Delta SGRQ) score = -9.9 +/- 15.3 units] than for GOLD stage IV patients (n = 7; Delta RV/TLC = -0.5 +/- 6.4%; Delta FEV 1 = +2.3 +/- 12.3%; Delta FVC = +2.6 +/- 21.1%; Delta DLCO = -2.8 +/- 17.2%; Delta 6MWD = +28.3 +/- 58.4 m; Delta MRCD = 0.3 +/- 0.81 units; Delta SGRQ = -6.7 +/- 7.0 units). Conclusions: ELS therapy shows promise for treating patients with advanced heterogeneous emphysema. Additional studies to assess responses in a larger cohort with a longer follow-up are warranted. Copyright (C) 2011 S. Karger AG, Base

    Optimal use of time dependent probability density data to extract potential energy surfaces

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    A novel algorithm was recently presented to utilize emerging time dependent probability density data to extract molecular potential energy surfaces. This paper builds on the previous work and seeks to enhance the capabilities of the extraction algorithm: An improved method of removing the generally ill-posed nature of the inverse problem is introduced via an extended Tikhonov regularization and methods for choosing the optimal regularization parameters are discussed. Several ways to incorporate multiple data sets are investigated, including the means to optimally combine data from many experiments exploring different portions of the potential. Results are presented on the stability of the inversion procedure, including the optimal combination scheme, under the influence of data noise. The method is applied to the simulated inversion of a double well system.Comment: 34 pages, 5 figures, LaTeX with REVTeX and Graphicx-Package; submitted to PhysRevA; several descriptions and explanations extended in Sec. I

    Bandwidth-controlled Mott transition in κ(BEDTTTF)2Cu[N(CN)2]BrxCl1x\kappa-(BEDT-TTF)_2 Cu [N(CN)_2] Br_x Cl_{1-x} I. Optical studies of localized charge excitations

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    Infrared reflection measurements of the half-filled two-dimensional organic conductors κ\kappa-(BEDT-TTF)2_2Cu[N(CN)2_{2}]Brx_{x}Cl1x_{1-x} were performed as a function of temperature (5K<T<3005 {\rm K}<T<300 K) and Br-substitution (x=0x=0%, 40%, 73%, 85%, and 90%) in order to study the metal-insulator transition. We can distinguish absorption processes due to itinerant and localized charge carriers. The broad mid-infrared absorption has two contributions: transitions between the two Hubbard bands and intradimer excitations from the charges localized on the (BEDT-TTF)2_2 dimer. Since the latter couple to intramolecular vibrations of BEDT-TTF, the analysis of both electronic and vibrational features provides a tool to disentangle these contributions and to follow their temperature and electronic-correlations dependence. Calculations based on the cluster model support our interpretation.Comment: 12 pages, 12 figure

    Sterile Neutrinos in E_6 and a Natural Understanding of Vacuum Oscillation Solution to the Solar Neutrino Puzzle

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    If Nature has chosen the vacuum oscillation solution to the Solar neutrino puzzle, a key theoretical challenge is to understand the extreme smallness of the ΔmνeνX2\Delta m^2_{\nu_e-\nu_X} (1010eV2\sim 10^{-10} eV^2) required for the purpose. We find that in a class of models such as [SU(3)]^3 or its parent group E_6, which contain one sterile neutrino, νis\nu_{is} for each family, the Δmνiνis2\Delta m^2_{\nu_i-\nu_{is}} is proportional to the cube of the lepton Yukawa coupling. Therefore fitting the atmospheric neutrino data then predicts the νeνes\nu_e-\nu_{es} mass difference square to be (memμ)3Δmatmos2\sim (\frac{m_e}{m_{\mu}})^3 \Delta m^2_{atmos}, where the atmospheric neutrino data is assumed to be solved via the νμνμs\nu_{\mu}-\nu_{\mu s} oscillation. This provides a natural explanation of the vacuum oscillation solution to the solar neutrino problem.Comment: 7 pages, UMD-PP-99-109; new references added; no other chang

    Evidence for structural and electronic instabilities at intermediate temperatures in κ\kappa-(BEDT-TTF)2_{2}X for X=Cu[N(CN)2_{2}]Cl, Cu[N(CN)2_{2}]Br and Cu(NCS)2_{2}: Implications for the phase diagram of these quasi-2D organic superconductors

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    We present high-resolution measurements of the coefficient of thermal expansion α(T)=lnl(T)/T\alpha (T)=\partial \ln l(T)/\partial T of the quasi-twodimensional (quasi-2D) salts κ\kappa-(BEDT-TTF)2_2X with X = Cu(NCS)2_2, Cu[N(CN)2_2]Br and Cu[N(CN)2_2]Cl. At intermediate temperatures (B), distinct anomalies reminiscent of second-order phase transitions have been found at T=38T^\ast = 38 K and 45 K for the superconducting X = Cu(NCS)2_2 and Cu[N(CN)2_2]Br salts, respectively. Most interestingly, we find that the signs of the uniaxial pressure coefficients of TT^\ast are strictly anticorrelated with those of TcT_c. We propose that TT^\ast marks the transition to a spin-density-wave (SDW) state forming on minor, quasi-1D parts of the Fermi surface. Our results are compatible with two competing order parameters that form on disjunct portions of the Fermi surface. At elevated temperatures (C), all compounds show α(T)\alpha (T) anomalies that can be identified with a kinetic, glass-like transition where, below a characteristic temperature TgT_g, disorder in the orientational degrees of freedom of the terminal ethylene groups becomes frozen in. We argue that the degree of disorder increases on going from the X = Cu(NCS)2_2 to Cu[N(CN)2_2]Br and the Cu[N(CN)2_2]Cl salt. Our results provide a natural explanation for the unusual time- and cooling-rate dependencies of the ground-state properties in the hydrogenated and deuterated Cu[N(CN)2_2]Br salts reported in the literature.Comment: 22 pages, 7 figure

    Combined QCD and electroweak analysis of HERA data

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    A simultaneous fit of parton distribution functions (PDFs) and electroweak parameters to HERA data on deep inelastic scattering is presented. The input data are the neutral current and charged current inclusive cross sections which were previously used in the QCD analysis leading to the HERAPDF2.0 PDFs. In addition, the polarisation of the electron beam was taken into account for the ZEUS data recorded between 2004 and 2007. Results on the vector and axial-vector couplings of the Z boson to u- and d-type quarks, on the value of the electroweak mixing angle and the mass of the W boson are presented. The values obtained for the electroweak parameters are in agreement with Standard Model predictions.Comment: 32 pages, 10 figures, accepted by Phys. Rev. D. Small corrections from proofing process and small change to Fig. 12 and Table
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