16,273 research outputs found

    Moral tragedy

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    Polemizując z poglądami niektórych filozofów moralności, autor broni tezy, iż jednoznacznie dobrzy ludzie mogą być pewni spokoju swej duszy

    Unveiling the Effect of Magnetic Noise in the Coherence of Single-Molecule Quantum Processors

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    Quantum bits (qubits) constitute the most elementary building-blocks of any quantum technology, where information is stored and processed in the form of quantum superpositions between discrete energy levels. In particular, the fabrication of quantum processors is a key long-term goal that will allow us conducting specific tasks much more efficiently than the most powerful classical computers can do. Motivated by recent experiments in which three addressable spin qubits are defined on a potential single-molecule quantum processor, namely the [Gd(H2O)P5W30O110]12− polyoxometalate, we investigate the decohering effect of magnetic noise on the encoded quantum information. Our state-of-the-art model, which provides more accurate results than previous estimates, show a noticeable contribution of magnetic noise in limiting the survival timescale of the qubits. Yet, our results suggest that it might not be the only dephasing mechanism at play but other mechanisms, such as lattice vibrations and physical movement of magnetic nuclei, must be considered to understand the whole decoherence process

    Shortening of the Short Refractory Periods in Short QT Syndrome.

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    BACKGROUND: Diagnosis of short QT syndrome (SQTS) remains difficult in case of borderline QT values as often found in normal populations. Whether some shortening of refractory periods (RP) may help in differentiating SQTS from normal subjects is unknown. METHODS AND RESULTS: Atrial and right ventricular RP at the apex and right ventricular outflow tract as determined during standard electrophysiological study were compared between 16 SQTS patients (QTc 324±24 ms) and 15 controls with similar clinical characteristics (QTc 417±32 ms). Atrial RP were significantly shorter in SQTS compared with controls at 600- and 500-ms basic cycle lengths. Baseline ventricular RP were significantly shorter in SQTS patients than in controls, both at the apex and right ventricular outflow tract and for any cycle length. Differences remained significant for RP of any subsequent extrastimulus at any cycle length and any pacing site. A cut-off value of baseline RP <200 ms at the right ventricular outflow tract either at 600- or 500-ms cycle length had a sensitivity of 86% and a specificity of 100% for the diagnosis of SQTS. CONCLUSIONS: Patients with SQTS have shorter ventricular RP than controls, both at baseline during various cycle lengths and after premature extrastimuli. A cut-off value of 200 ms at the right ventricular outflow tract during 600- and 500-ms basic cycle length may help in detecting true SQTS from normal subjects with borderline QT values

    Numerical Modeling of the Early Light Curves of Type IIP Supernovae

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    The early rise of Type IIP supernovae (SN IIP) provides important information for constraining the properties of their progenitors. This can in turn be compared to pre-explosion imaging constraints and stellar models to develop a more complete picture of how massive stars evolve and end their lives. Using the SuperNova Explosion Code (SNEC), we model the first 40 days of SNe IIP to better understand what constraints can be derived from their early light curves. We use two sets of red supergiant progenitor models with zero-age main sequence masses in the range between 9 Msol and 20 Msol. We find that the early properties of the light curve depend most sensitively on the radius of the progenitor, and thus provide a relation between the g-band rise time and the radius at the time of explosion. This relation will be useful for deriving constraints on progenitors from future observations, especially in cases where detailed modeling of the entire rise is not practical. When comparing to observed rise times, the radii we find are a factor of a few larger than previous semi-analytic derivations and generally in better agreement with what is found with current stellar evolution calculations.Comment: 8 pages, 7 figure

    Notas sobre el "xirolarru" en el País Vasco

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    Se estudia la existencia de la gaita de odre o cornamusa en Euskadi. Primeramente se hace un análisis de las voces "gaita" y "dulzaina" para saber a que instrumento se refieren en cada caso y posteriormente se estudian las cornamusas de zonas cercanas a Euskadi, concluyendo que en algún momento este instrumento fue utilizado en Euskadi. Se presentan melodías y apuntes iconográficos sobre la cornamus

    Congenital Short QT Syndrome

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    Long QT intervals in the ECG have long been associated with sudden cardiac death. The congenital long QT syndrome was first described in individuals with structurally normal hearts in 1957.1 Little was known about the significance of a short QT interval. In 1993, after analyzing 6693 consecutive Holter recordings Algra et al concluded that an increased risk of sudden death was present not only in patients with long QT interval, but also in patients with short QT interval (<400 ms).2 Because this was a retrospective analysis, further evaluation of the data was not possible. It was not until 2000 that a short-QT syndrome (SQTS) was proposed as a new inherited clinical syndrome by Gussak et al.3 The initial report was of two siblings and their mother all of whom displayed persistently short QT interval. The youngest was a 17 year old female presenting with several episodes of paroxysmal atrial fibrillation requiring electrical cardioversion.3 Her QT interval measured 280 msec at a heart rate of 69. Her 21 year old brother displayed a QT interval of 272 msec at a heart rate of 58, whereas the 51 year old mother showed a QT of 260 msec at a heart rate of 74. The authors also noted similar ECG findings in another unrelated 37 year old patient associated with sudden cardiac death
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