136 research outputs found

    Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET

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    The velocity-space sensitivities of fast-ion diagnostics are often described by so-called weight functions. Recently, we formulated weight functions showing the velocity-space sensitivity of the often dominant beam-target part of neutron energy spectra. These weight functions for neutron emission spectrometry (NES) are independent of the particular NES diagnostic. Here we apply these NES weight functions to the time-of-flight spectrometer TOFOR at JET. By taking the instrumental response function of TOFOR into account, we calculate time-of-flight NES weight functions that enable us to directly determine the velocity-space sensitivity of a given part of a measured time-of-flight spectrum from TOFOR

    Relationship of edge localized mode burst times with divertor flux loop signal phase in JET

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    A phase relationship is identified between sequential edge localized modes (ELMs) occurrence times in a set of H-mode tokamak plasmas to the voltage measured in full flux azimuthal loops in the divertor region. We focus on plasmas in the Joint European Torus where a steady H-mode is sustained over several seconds, during which ELMs are observed in the Be II emission at the divertor. The ELMs analysed arise from intrinsic ELMing, in that there is no deliberate intent to control the ELMing process by external means. We use ELM timings derived from the Be II signal to perform direct time domain analysis of the full flux loop VLD2 and VLD3 signals, which provide a high cadence global measurement proportional to the voltage induced by changes in poloidal magnetic flux. Specifically, we examine how the time interval between pairs of successive ELMs is linked to the time-evolving phase of the full flux loop signals. Each ELM produces a clear early pulse in the full flux loop signals, whose peak time is used to condition our analysis. The arrival time of the following ELM, relative to this pulse, is found to fall into one of two categories: (i) prompt ELMs, which are directly paced by the initial response seen in the flux loop signals; and (ii) all other ELMs, which occur after the initial response of the full flux loop signals has decayed in amplitude. The times at which ELMs in category (ii) occur, relative to the first ELM of the pair, are clustered at times when the instantaneous phase of the full flux loop signal is close to its value at the time of the first ELM

    Guidelines and protocols for cardiovascular magnetic resonance in children and adults with congenital heart disease: SCMR expert consensus group on congenital heart disease

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    Hallux valgus severity, great toe pain, and plantar pressures during gait: A cross-sectional study of community-dwelling adults.

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    BACKGROUND: Hallux valgus (HV) is a common disabling condition affecting 36% of adults aged 65 years and over. Identifying whether the severity of the deformity alters weight-bearing patterns during walking may assist clinicians optimize offloading interventions. Therefore, we examined how plantar pressure distributions during walking are affected by HV severity. METHODS: Plantar pressures and maximum forces in ten regions of the foot were obtained from 120 participants (40 men, 80 women) aged ≥50 years using a pressure platform (RSscan® International, Olen, Belgium). HV severity was documented using a validated line-drawing instrument with participants separated into four groups: none (n = 30), mild (n = 30), moderate (n = 30) and severe (n = 30). Pressure and force values were compared across HV severity, stratified by the presence or absence of great toe pain. RESULTS: Participants with severe HV were more likely to have great toe pain. More severe HV was associated with significant reductions in peak pressure and maximum force under the hallux but not at other sites of the foot. This association appeared strongest in those reporting great toe pain. CONCLUSIONS: Greater HV severity is associated with great toe pain and reduced loading under the hallux when walking. These observed changes in plantar pressure and maximum force may reflect a pain avoidance mechanism
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