695 research outputs found

    Phonon relaxation of subgap levels in superconducting quantum point contacts

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    Superconducting quantum point contacts are known to possess two subgap states per each propagating mode. In this note we compute the low-temperature relaxation rate of the upper subgap state into the lower one with the emission of an acoustic phonon. If the reflection in the contact is small, the relaxation time may become much longer than the characteristic lifetime of a bulk quasiparticle.Comment: REVTeX, 4 page

    Serious complication 1 year after sacrospinous ligament fixation

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    Myositis of the gluteal region caused by group A streptococci 1 year after a sacrospinous ligament fixation was recognised as a serious complication of this procedure. Most likely, the infection was spread to the gluteal region through a port d’entree caused by vaginal atrophy, via the non-resorbable sutures. The patient was treated successfully with antibiotics intravenous and local estrogens

    Implementation of automatic speech analysis for early detection of psychiatric symptoms:What do patients want?

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    Psychiatry is in dire need of a method to aid early detection of symptoms. Recent developments in automatic speech analysis prove promising in this regard, and open avenues for implementation of speech-based applications to detect psychiatric symptoms. The current survey was conducted to assess positions with regard to speech recordings among a group (n = 675) of individuals who experience psychiatric symptoms. Overall, respondents are open to the idea of speech recordings in light of their mental welfare. Importantly, concerns with regard to privacy were raised. Given that speech recordings are privacy sensitive, this requires special attention upon implementation of automatic speech analysis techniques. Furthermore, respondents indicated a preference for speech recordings in the presence of a clinician, as opposed to a recording made at home without the clinician present. In developing a speech marker for psychiatry, close collaboration with the intended users is essential to arrive at a truly valid and implementable method

    Spontaneous brain activity underlying auditory hallucinations in the hearing-impaired

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    Auditory hallucinations, the perception of a sound without a corresponding source, are common in people with hearing impairment. Two forms can be distinguished: simple (i.e., tinnitus) and complex hallucinations (speech and music). Little is known about the precise mechanisms underlying these types of hallucinations. Here we tested the assumption that spontaneous activity in the auditory pathways, following deafferentation, underlies these hallucinations and is related to their phenomenology. By extracting (fractional) Amplitude of Low Frequency Fluctuation [(f)ALFF] scores from resting state fMRI of 18 hearing impaired patients with complex hallucinations (voices or music), 18 hearing impaired patients with simple hallucinations (tinnitus or murmuring), and 20 controls with normal hearing, we investigated differences in spontaneous brain activity between these groups. Spontaneous activity in the anterior and posterior cingulate cortex of hearing-impaired groups was significantly higher than in the controls. The group with complex hallucinations showed elevated activity in the bilateral temporal cortex including Wernicke's area, while spontaneous activity of the group with simple hallucinations was mainly located in the cerebellum. These results suggest a decrease in error monitoring in both hearing-impaired groups. Spontaneous activity of language-related areas only in complex hallucinations suggests that the manifestation of the spontaneous activity represents the phenomenology of the hallucination. The link between cerebellar activity and simple hallucinations, such as tinnitus, is new and may have consequences for treatment. (C) 2020 The Author(s). Published by Elsevier Ltd

    Subharmonic Shapiro steps and assisted tunneling in superconducting point contacts

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    We analyze the current in a superconducting point contact of arbitrary transmission in the presence of a microwave radiation. The interplay between the ac Josephson current and the microwave signal gives rise to Shapiro steps at voltages V = (m/n) \hbar \omega_r/2e, where n,m are integer numbers and \omega_r is the radiation frequency. The subharmonic steps (n different from 1) are a consequence of the ocurrence of multiple Andreev reflections (MAR) and provide an unambiguous signature of the peculiar ac Josephson effect at high transmission. Moreover, the dc current exhibits a rich subgap structure due to photon-assisted MARs.Comment: Revtex, 4 pages, 4 figure

    Experimental Test of the Inter-Layer Pairing Models for High-Tc Superconductivity Using Grazing Incidence Infrared Reflectometry

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    From measurements of the far-infrared reflectivity at grazing angles of incidence with p-polarized light we determined the c-axis Josephson plasma frequencies of the single layer high T_c cuprates Tl_2Ba_2CuO_6 and La_{2-x}Sr_xCuO_4. We detected a strong plasma resonance at 50 cm^{-1} for La_{2-x}Sr_xCuO_4 in excellent agreement with previously published results. For Tl_2Ba_2CuO_6 we were able to determine an upper limit of the unscreened c-axis Josephson plasma frequency 100 cm^{-1} or a c-axis penetration depth > 15 \mu m. The small value of ωJ\omega_J stands in contrast to recent a prediction based on the inter-layer tunneling mechanism of superconductivity.Comment: 4 pages, Phys. Rev. B, in press, Revtex, 4 postscript figure

    Gamow-Teller strength in 54Fe and 56Fe

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    Through a sequence of large scale shell model calculations, total Gamow-Teller strengths (S+S_+ and SS_-) in 54^{54}Fe and 56^{56}Fe are obtained. They reproduce the experimental values once the στ\sigma\tau operator is quenched by the standard factor of 0.770.77. Comparisons are made with recent Shell Model Monte Carlo calculations. Results are shown to depend critically on the interaction. From an analysis of the GT+ and GT- strength functions it is concluded that experimental evidence is consistent with the 3(NZ)3(N-Z) sum rule.Comment: 6 pages, RevTeX 3.0 using psfig, 7 Postscript figures included using uufile

    Theory of AC Josepson Effect in Superconducting Constrictions

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    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

    Clinical outcomes and safety of rituximab treatment for patients with systemic lupus erythematosus (SLE) - results from a nationwide cohort in Germany (GRAID)

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    ObjectiveThe objective of this article is to evaluate the safety and clinical outcome of rituximab treatment in systemic lupus erythematosus (SLE) patients refractory to standard of care therapy in a real-life setting in Germany. MethodsThe GRAID registry included patients with different autoimmune diseases who were given off-label treatment with rituximab. Data on safety and clinical response were collected retrospectively. In SLE patients, clinical parameters included tender and swollen joint counts, fatigue, myalgia, general wellbeing, Raynaud's and the SLEDAI index. Laboratory tests included dsDNA antibody titres, complement factors, hematologic parameters and proteinuria. Finally, the investigators rated their patients as non-, partial or complete responders based on clinical grounds. ResultsData from 85 SLE patients were collected, 69 female and 16 male, with a mean disease duration of 9.8 years. The mean follow-up period was 9.67.4 months, resulting in 66.8 patient years of observation. A complete response was reported in 37 patients (46.8%), partial response in 27 (34.2%), no response in 15 (19.0%). On average, major clinical as well as laboratory efficacy parameters improved substantially, with the SLEDAI decreasing significantly from 12.2 to 3.3 points. Concerning safety, one infusion reaction leading to discontinuation of treatment occurred. Infections were reported with a rate of 19.5 (including six severe infections) per 100 patient years. ConclusionWith the restrictions of a retrospective data collection, the results of this study confirm data of other registries, which suggest a favourable benefit-risk ratio of rituximab in patients with treatment-refractory SLE
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