308 research outputs found

    Decoherence-protected quantum gates for a hybrid solid-state spin register

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    Protecting the dynamics of coupled quantum systems from decoherence by the environment is a key challenge for solid-state quantum information processing. An idle qubit can be efficiently insulated from the outside world via dynamical decoupling, as has recently been demonstrated for individual solid-state qubits. However, protection of qubit coherence during a multi-qubit gate poses a non-trivial problem: in general the decoupling disrupts the inter-qubit dynamics, and hence conflicts with gate operation. This problem is particularly salient for hybrid systems, wherein different types of qubits evolve and decohere at vastly different rates. Here we present the integration of dynamical decoupling into quantum gates for a paradigmatic hybrid system, the electron-nuclear spin register. Our design harnesses the internal resonance in the coupled-spin system to resolve the conflict between gate operation and decoupling. We experimentally demonstrate these gates on a two-qubit register in diamond operating at room temperature. Quantum tomography reveals that the qubits involved in the gate operation are protected as accurately as idle qubits. We further illustrate the power of our design by executing Grover's quantum search algorithm, achieving fidelities above 90% even though the execution time exceeds the electron spin dephasing time by two orders of magnitude. Our results directly enable decoherence-protected interface gates between different types of promising solid-state qubits. Ultimately, quantum gates with integrated decoupling may enable reaching the accuracy threshold for fault-tolerant quantum information processing with solid-state devices.Comment: This is original submitted version of the paper. The revised and finalized version is in print, and is subjected to the embargo and other editorial restrictions of the Nature journa

    From External Evaluation, to School Self-evaluation, to Peer Review

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    Most modern systems of school education around the world now have highly developed evaluation processes. Following quickly in the wake of external evaluation policies have followed calls for schools to develop their own capacities for self-review. An OECD report (2013) describes a number of ways in which developing school evaluation capacity should be a priority for school improvement. Among the report’s suggestions are promoting peer learning among schools (pp. 469–470). This chapter describes the research on external evaluation, internal evaluation and the relationship between these two. It then moves on to define and describes peer review and chart its growth. The accountability dimension of peer review is also explored. Finally the existing evidence on peer review is presented from the vocational and schools sectors to show key findings so far, and key conditions for effective peer review are described

    Patient-reported outcome measures for asthma:a systematic review

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    BACKGROUND: Patient-reported outcome measures (PROMs) are measures of the outcome of treatment(s) reported directly by the patient or carer. There is increasing international policy interest in using these to assess the impact of clinical care. AIMS: To identify suitably validated PROMs for asthma and examine their potential for use in clinical settings. METHODS: We systematically searched MEDLINE, EMBASE and Web of Science databases from 1990 onwards to identify PROMs for asthma. These were critically appraised, then narratively synthesised. We also identified the generic PROMs commonly used alongside asthma-specific PROMs. RESULTS: We identifi ed 68 PROMs for asthma, 13 of which were selected through screening as being adequately developed to warrant full-quality appraisal: 8 for adults, 4 for children and 1 for a child's caregiver. The PROMs found to be sufficiently well validated to offer promise for use in clinical settings were the Asthma Quality of Life Questionnaire (AQLQ) and mini-AQLQ for adults, and Pediatric Asthma Quality of Life Questionnaire for children. Rhinasthma was considered promising in simultaneously assessing the impact of asthma and rhinitis in those with coexistent disease. We identified 28 generic PROMs commonly used in conjunction with asthma-specific instruments. CONCLUSIONS: We identified asthma PROMs that offer the greatest potential for use in clinical settings. Further work is needed to assess whether these are fit-for-purpose for use in clinical practice with individual patients. In particular, there is a need to ensure these are validated for use in clinical settings, acceptable to patients, caregivers and clinicians, and yield meaningful outcomes. © 2014 Primary Care Respiratory Society/Macmillan Publishers Limited

    Service Interaction Flow Analysis Technique for Service Personalization

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    Abstract Service interaction flows are difficult to capture, analyze, outline, and represent for research and design purposes. We examine how variation of personalized service flows in technology-mediated service interaction can be modeled and analyzed to provide information on how service personalization could support interaction. We have analyzed service interaction cases in a context of technology-mediated car rental service. With the analysis technique we propose, inspired by Interaction Analysis method, we were able to capture and model the situational service interaction. Our contribution regarding technology-mediated service interaction design is twofold: First, with the increased understanding on the role of personalization in managing variation in technology-mediated service interaction, our study contributes to designing service management information systems and human-computer interfaces that support personalized service interaction flows. Second, we provide a new analysis technique for situated interaction analysis, particularly when the aim is to understand personalization in service interaction flows

    Unchanged muscle fiber conduction velocity relates to mild acidosis during exhaustive bicycling

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    Muscle fiber conduction velocity (MFCV) has often been shown to decrease during standardized fatiguing isometric contractions. However, several studies have indicated that the MFCV may remain constant during fatiguing dynamic exercise. It was investigated if these observations can be related to the absence of a large decrease in pH and if MFCV can be considered as a good indicator of acidosis, also during dynamic bicycle exercise. High-density surface electromyography (HDsEMG) was combined with read-outs of muscle energetics recorded by in vivo 31P magnetic resonance spectroscopy (MRS). Measurements were performed during serial exhausting bouts of bicycle exercise at three different workloads. The HDsEMG recordings revealed a small and incoherent variation of MFCV during all high-intensity exercise bouts. 31P MRS spectra revealed a moderate decrease in pH at the end of exercise (~0.3 units down to 6.8) and a rapid ancillary drop to pH 6.5 during recovery 30 s post-exercise. This additional degree of acidification caused a significant decrease in MFCV during cycling immediately after the rest period. From the data a significant correlation between MFCV and [H+] ([H+] = 10−pH) was calculated (p < 0.001, Pearson’s R = −0.87). Our results confirmed the previous observations of MFCV remaining constant during fatiguing dynamic exercise. A constant MFCV is in line with a low degree of acidification, considering the presence of a correlation between pH and MFCV after further increasing acidification

    Neuromyopathy with congenital cataracts and glaucoma: A distinct syndrome caused by POLG variants

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    We identified three non-related patients manifesting a childhood-onset progressive neuromyopathy with congenital cataracts, delayed walking, distal weakness and wasting, glaucoma and swallowing difficulties. Electrophysiology and nerve biopsies showed a mixed axonal and demyelinating neuropathy, while muscle biopsy disclosed both neurogenic and myopathic changes with ragged red fibers, and muscle MRI showed consistent features across patients, with a peculiar concentric disto-proximal gradient of fatty replacement. We used targeted next generation sequencing and candidate gene approach to study these families. Compound biallelic heterozygous variants, p.[(Pro648Arg)]; [(His932Tyr)] and p.[(Thr251Ile),(Pro587Leu)]; [(Arg943Cys)], were found in the three patients causing this homogeneous phenotype. Our report on a subset of unrelated patients, that showed a distinct autosomal recessive childhood-onset neuromyopathy with congenital cataracts and glaucoma, expands the clinical spectrum of POLG-related disorders. It also confirms the association between cataracts and neuropathy with variants in POLG. Early onset cataract is otherwise rare in POLG-related disorders and so far reported only in a few patients with the clinical pattern of distal myopathy or neuromyopathy
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