956 research outputs found

    Tuning the proximity effect in a superconductor-graphene-superconductor junction

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    We have tuned in situ the proximity effect in a single graphene layer coupled to two Pt/Ta superconducting electrodes. An annealing current through the device changed the transmission coefficient of the electrode/graphene interface, increasing the probability of multiple Andreev reflections. Repeated annealing steps improved the contact sufficiently for a Josephson current to be induced in graphene.Comment: Accepted for publication in Phys. Rev.

    Nonequilibrium effects due to charge fluctuations in intrinsic Josephson systems

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    Nonequilibrium effects in layered superconductors forming a stack of intrinsic Josephson junctions are investigated. We discuss two basic nonequilibrium effects caused by charge fluctuations on the superconducting layers: a) the shift of the chemical potential of the condensate and b) charge imbalance of quasi-particles, and study their influence on IV-curves and the position of Shapiro steps.Comment: 17 pages, 2 figures, revised version slightly shortene

    A mixed methods analysis of clozapine errors reported to the National Reporting and Learning System

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    Purpose: To review and analyse medication errors related to clozapine, an atypical antipsychotic, that were reported to the National Reporting and Learning System (NRLS). Methods: Following extraction of one year of clozapine related errors from the NRLS, a qualitative analysis (thematic analysis and re-classification) and quantitative analysis was performed. An incident was considered a clozapine error if there was a failure in its medication process (i.e. an error in the prescribing, dispensing, preparing, administering, monitoring or advising of clozapine). Results: “Issues with stock/supply/ordering” was the most common theme derived from the qualitative thematic analysis (n = 338), followed by wrong dose/strength/frequency (n = 221) and medication omissions (n = 202). Most errors occurred in the “administration/supply” medication stage. Over half of reported clozapine incidents involved people 26 to 55 years old (n = 830) and 82% of errors were reported by mental health services (n = 1270). Only 1.5% of reports were classed as moderate/severe harm. Conclusion: Issues with availability, stock, and supply were found to be the most common causes. This usually entailed a lack of stock to fulfil a patient's dose/supply. Such incidents could potentially be reduced by improved management of the supply process, and liaison between pharmacy and clinical staff. The implementation of emergency drug cupboards at the discretion of an on-call pharmacist may prove to be a preventative measure for such errors. Despite the potential adverse effects associated with clozapine, very few incidents led to moderate/severe harm. Encouragement of NRLS reporting is recommended for incidents of all degrees of harm

    Charge-imbalance effects in intrinsic Josephson systems

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    We report on two types of experiments with intrinsic Josephson systems made from layered superconductors which show clear evidence of nonequilibrium effects: 1. In 2-point measurements of IV-curves in the presence of high- frequency radiation a shift of the voltage of Shapiro steps from the canonical value hf/(2e) has been observed. 2. In the IV-curves of double-mesa structures an influence of the current through one mesa on the voltage measured on the other mesa is detected. Both effects can be explained by charge-imbalance on the superconducting layers produced by the quasi-particle current, and can be described successfully by a recently developed theory of nonequilibrium effects in intrinsic Josephson systems.Comment: 8pages, 9figures, submitted to Phys. Rev.

    Examining exercise dependence symptomatology from a self-determination perspective

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    Background: Based on the theoretical propositions of Self-Determination Theory (SDT; Deci & Ryan, 1985) this study examined whether individuals classified as “nondependent-symptomatic” and “nondependent-asymptomatic” for exercise dependence differed in terms of the level of exercise-related psychological need satisfaction and self-determined versus controlling motivation they reported. Further, we examined if the type of motivational regulations predicting exercise behaviour differed among these groups. Methods: Participants (N = 339), recruited from fitness, community, and retail settings, completed measures of exercise-specific psychological need satisfaction, motivational regulations, exercise behaviour and exercise dependence. Results: Individuals who were nondependent-symptomatic for exercise dependence reported higher levels of competence need satisfaction and all forms of motivational regulation, compared to nondependent-asymptomatic individuals. Introjected regulation approached significance as a positive predictor of strenuous exercise behaviour for symptomatic individuals. Identified regulation was a positive predictor of strenuous exercise for asymptomatic individuals. Conclusions: The findings reinforce the applicability of SDT to understanding engagement in exercise

    Persuasiveness of eWOM communications: Literature review and suggestions for future research

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    YesElectronic word-of-mouth (eWOM) plays an important part in consumer purchase decision. The way consumers perceive the persuasiveness of eWOM message can affect their attitude, and purchase intention, and hence sales. Thus, the topic of persuasiveness of eWOM communications has received much attention from scholars. The objective of this paper is to provide a brief review of the existing literature related to the effectiveness of eWOM communications and offer an overview of the determinants of eWOM persuasiveness. This paper contributes to the existing eWOM literature by reviewing the existing studies on eWOM communications, identifying gaps in the current research and providing directions for future research

    Growing old in England: economic and social issues

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    This paper examines the economic and social impact of changes in the duration of working life for the 80 per cent of older adults living in urban England. While some people are experiencing extended retirement because of moving out of paid work in their fifties, a growing minority of those beyond the state retirement age continue in paid employment. This paper highlights the considerable challenges for urban policy makers in addressing the economic and social inclusion of all older adults

    Observation of Andreev reflection in the c-axis transport of Bi_2Sr_2CaCu_2O_{8+x} single crystals near T_c and search for the preformed-pair state

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    We observed an enhancement of the cc-axis differential conductance around the zero-bias in Au//Bi2_2Sr2_2CaCu2_2O8+x_{8+x} (Bi2212) junctions near the superconducting transition temperature TcT_c. We attribute the conductance enhancement to the Andreev reflection between the surface Cu-O bilayer with suppressed superconductivity and the neighboring superconducting inner bilayer. The continuous evolution from depression to an enhancement of the zero-bias differential conductance, as the temperature approaches TcT_c from below, points to weakening of the barrier strength of the non-superconducting layer between adjacent Cu-O bilayers. We observed that the conductance enhancement persisted up to a few degrees above TcT_c in junctions prepared on slightly overdoped Bi2212 crystals. However, no conductance enhancement was observed above TcT_c in underdoped crystals, although recently proposed theoretical consideration suggests an even wider temperature range of enhanced zero-bias conductance. This seems to provide negative perspective to the existence of the phase-incoherent preformed pairs in the pseudogap state.Comment: 17 pages including 4 figure
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