977 research outputs found

    Quasiballistic correction to the density of states in three-dimensional metal

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    We study the exchange correction to the density of states in the three-dimensional metal near the Fermi energy. In the ballistic limit, when the distance to the Fermi level exceeds the inverse transport relaxation time 1/τ1/\tau, we find the correction linear in the distance from the Fermi level. By a large parameter ϵFτ\epsilon_{\rm F} \tau this ballistic correction exceeds the diffusive correction obtained earlier.Comment: 2 pages, 1 figur

    Proximity effect in ultrathin Pb/Ag multilayers within the Cooper limit

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    We report on transport and tunneling measurements performed on ultra-thin Pb/Ag (strong coupled superconductor/normal metal) multilayers evaporated by quench condensation. The critical temperature and energy gap of the heterostructures oscillate with addition of each layer, demonstrating the validity of the Cooper limit model in the case of multilayers. We observe excellent agreement with a simple theory for samples with layer thickness larger than 30\AA . Samples with single layers thinner than 30\AA deviate from the Cooper limit theory. We suggest that this is due to the "inverse proximity effect" where the normal metal electrons improve screening in the superconducting ultrathin layer and thus enhance the critical temperature.Comment: 4 pages, 4 figure

    Cyclical vomiting syndrome secondary to a Chiari I malformation - a case report

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    Background: Cyclical vomiting syndrome is a disorder characterised by recurrent episodes of profuse vomiting. There are no cases in the literature on the management of children with presenting with cyclical vomiting syndrome and a Chiari malformation type I. Discussion: We report the case of a 12-year-old child diagnosed with cyclical vomiting syndrome and a Chiari malformation type I. The patient received symptomatic relief following a craniocervical decompression

    Coulomb gap in a model with finite charge transfer energy

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    The Coulomb gap in a donor-acceptor model with finite charge transfer energy Δ\Delta describing the electronic system on the dielectric side of the metal-insulator transition is investigated by means of computer simulations on two- and three-dimensional finite samples with a random distribution of equal amounts of donor and acceptor sites. Rigorous relations reflecting the symmetry of the model presented with respect to the exchange of donors and acceptors are derived. In the immediate neighborhood of the Fermi energy μ\mu the the density of one-electron excitations g(ϵ)g(\epsilon) is determined solely by finite size effects and g(ϵ)g(\epsilon) further away from μ\mu is described by an asymmetric power law with a non-universal exponent, depending on the parameter Δ\Delta.Comment: 10 pages, 6 figures, submitted to Phys. Rev.

    OC-040 A pre-endoscopy point of care test (iga/igg-deamidated gliadin peptide) as a case finding tool for coeliac diseasein secondary care

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    Coeliac disease (CD) is common yet underdiagnosed. 12.4% CD patients had a gastroscopy within 5 years without duodenal biopsies taken, and coeliac serology was performed in only 30% of patients with anaemia or suspected CD. A pre-endoscopy point of care test (POCT) could potentially fill this gap. We aimed to evaluate the diagnostic accuracy and acceptability of the POCT, Simtomax (IgA/IgG-deamidated gliadin peptide, Tillotts Pharma, Rheinfelden, Switzerland), in detecting CD

    Optical Spectra of SNR Candidates in NGC 300

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    We present moderate-resolution (<5A) long-slit optical spectra of 51 nebular objects in the nearby Sculptor Group galaxy NGC 300 obtained with the 2.3 meter Advanced Technology Telescope at Siding Spring Observatory, Australia. Adopting the criterion of [SII]/Ha>=0.4 to confirm supernova remnants (SNRs) from optical spectra, we find that of 28 objects previously proposed as SNRs from optical observations, 22 meet this criterion with six showing [SII]/Ha of less than 0.4. Of 27 objects suggested as SNRs from radio data, four are associated with the 28 previously proposed SNRs. Of these four, three (included in the 22 above) meet the criterion. In all, 22 of the 51 nebular objects meet the [SII]/Ha criterion as SNRs while the nature of the remaining 29 objects remains undetermined by these observations.Comment: Accepted for publication in Astrophysics & Space Scienc
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