115 research outputs found
Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET
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
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
J.L. Down to Cheryll Tickle, 1970
Letter announcing that Tickle's application for a NATO Research Fellowship was successful.Typed document1-pageCorrespondenc
Detection of prostate cancer in unselected young men: prospective cohort nested within a randomised controlled trial
Objective:
To investigate the feasibility of testing for prostate cancer
and the prevalence and characteristics of the disease in unselected
young men.
Design:
Prospective cohort nested within a randomised controlled trial,
with two years of follow-up.
Setting:
Eight general practices in a UK city.
Participants:
1299 unselected men aged 45-49.
Intervention:
Prostate biopsies for participants with a prostate
specific antigen level of 1.5 ng/ml or more and the possibility of
randomisation to three treatments for those with localised prostate
cancer.
Main outcome measures:
Uptake of testing for prostate specific antigen;
positive predictive value of prostate specific antigen; and prevalence
of prostate cancer, TNM disease stage, and histological grade (Gleason
score 6-10).
Results 442 of 1299 men agreed to be tested for prostate specific
antigen (34%) and 54 (12%) had a raised level. The positive predictive
value for prostate specific antigen was 21.3%. Ten cases of prostate
cancer were detected (2.31/6) with eight having at least two positive
results in biopsy cores and three showing perineural invasion. One
tumour was of high volume (cT2c), Gleason score 7, with a positive
result on digital rectal examination; nine tumours were cT1c, Gleason
score 6, and eight had a negative result on digital rectal examination.
Five of the nine eligible participants (55%) agreed to be randomised.
No biochemical disease progression occurred in two years of follow-up.
Conclusions:
Men younger than 50 will accept testing for prostate cancer
but at a much tower rate than older men. Using an age based threshold
of 1.5 ng/ml, the prevalence of prostate cancer was similar to that in
older men (3.0 ng/ml threshold) and some cancers of potential clinical
significance were found
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