360 research outputs found

    Condition Monitoring of Power Cables

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    A National Grid funded research project at Southampton has investigated possible methodologies for data acquisition, transmission and processing that will facilitate on-line continuous monitoring of partial discharges in high voltage polymeric cable systems. A method that only uses passive components at the measuring points has been developed and is outlined in this paper. More recent work, funded through the EPSRC Supergen V, UK Energy Infrastructure (AMPerES) grant in collaboration with UK electricity network operators has concentrated on the development of partial discharge data processing techniques that ultimately may allow continuous assessment of transmission asset health to be reliably determined

    Preliminary investigation on the feasibility of radiometric techniques to detect faults in buried cable joints

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    This paper investigates the preliminary use of radiometric techniques to the detection of PDs in buried cables, and in particular to cable joints. The transfer function from the source to the detector is a function of the propagation characteristics of the media involved. In the case of radiometric detection the inclusion of soil, in general a lossy and dispersive medium with frequency and content dependent characteristics, further contributes to signal attenuation. The work undertaken here examines whether a repetitive pulse of varying amplitude and frequency, injected into an experimental arrangement that simulates buried power cables, is being detected by two simple antennae above ground. Successful detection of the pulses showed the preliminary possibility of the use of such techniques in PD detection, which creates the need for further experiments and antenna designs to be explored

    Randomised trials in the South African Medical Journal, 1948- 1997

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    Objective. To describe randomised controlled trials (RCTs) published in the South African Medical Journal (SAMJ) over a 50-year period from 1948 to 1997 with regard to number, topic and quality.Methods. We hand searched all issues of the SAMJ published during the study period to identify all published RCTs.Outcome measures. Number, topic and quality of RCTs published from 1948 to 1997.Results. Eight hundred and fifty-eight clinical trials were published during the period reviewed. Eighty-four per cent of RCTs were published as full articles. During the 1980s the number of RCTs published increased rapidly,  with a peak of 35 in 1985, but then declined to only 5 in 1997. The majority (92%) of RCTs were conducted in a hospital setting. A varied range of subjects was covered, with gastroenterology taking the lead and no trials in public health. The sample size in more than 50% of RCTs was smaller than 50 patients. Fifty-one per cent (435 trials) used random allocation and 49% (423) quasi-random methods of allocation. Concealment of treatment allocation was judged to be adequate in 46% of studies (N == 200), blinding of observers assessing outcomes was adequate in 28% (123), and all the allocated test subjects were included in the primary analysis in 28% (123). The follow-up period was more than 1 year in 4% (17) and less than 6 days in 16% (71).Conclusions. Compared with other international journals the SAMJ is highly regarded in terms of the number of trials published. There are, however, a number of deficiencies in the quality of the trials

    Issue in Child Health: Can a new paediatric sub-specialty improve child health in South Africa?

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    Compared with other middle-income countries, child health in South Africa is in a poor state, and should be addressed by focusing on the healthcare needs of all children across a system or region. Paediatricians have had little effect on this situation, partly because their training is not aligned with South African needs. The proposed re-engineering of primary healthcare will belimited by the skewed distribution of staff and the lack of suitable skills. A ‘community’ placement during specialist training, and the creation of a sub-specialty in Community Paediatrics and Child Health, could address the skills shortage and possibly attract health personnel to under-served areas through creating an appropriate career path. This proposal would also support the Department of Health’s encouraging plans to re-engineer primary healthcare

    Longitudinal associations between conflict monitoring and emergent academic skills: An event‐related potentials study

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    Identifying the links between specific cognitive functions and emergent academic skills can help determine pathways to support both early academic performance and later academic achievement. Here, we investigated the longitudinal associations between a key aspect of cognitive control, conflict monitoring, and emergent academic skills from preschool through first grade, in a large sample of socioeconomically diverse children (N = 261). We recorded event‐related potentials (ERPs) during a Go/No‐Go task. The neural index of conflict monitoring, ΔN2, was defined as larger N2 mean amplitudes for No‐Go versus Go trials. ΔN2 was observed over the right hemisphere across time points and showed developmental stability. Cross‐lagged panel models revealed prospective links from ΔN2 to later math performance, but not reading performance. Specifically, larger ΔN2 at preschool predicted higher kindergarten math performance, and larger ΔN2 at kindergarten predicted higher first‐grade math performance, above and beyond the behavioral performance in the Go/No‐Go task. Early academic skills did not predict later ΔN2. These findings provided electrophysiological evidence for the contribution of conflict monitoring abilities to emergent math skills. In addition, our findings suggested that neural indices of cognitive control can provide additional information in predicting emergent math skills, above and beyond behavioral task performance.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149228/1/dev21809.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149228/2/dev21809_am.pd

    International collaboration, funding and association with burden of disease in randomized controlled trials in Africa

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    OBJECTIVE: This study aimed to assess whether randomized controlled trials conducted in Africa with collaborators from outside Africa were more closely associated with health conditions that have a burden of disease that is of specific importance to Africa than with conditions of more general global importance or with conditions important to developed countries. We also assessed whether the source of funding influenced a study's relevance to Africa. METHODS: We compared randomized controlled trials performed in Africa that looked at diseases specifically relevant to Africa (as determined by burden of disease criteria) with trials classified as looking at diseases of global importance or diseases important to developed countries in order to assess differences in collaboration and funding. FINDINGS: Of 520 trials assessed, 347 studied diseases that are specifically important to Africa; 99 studied globally important diseases and 74 studied diseases that are important to developed countries. The strongest independent predictor of whether a study was of specifically African or global importance was the corresponding author's country of origin: African importance was negatively associated with a corresponding author being from South Africa (odds ratio (OR) = 0.04; 95% confidence interval (CI) = 0.02–0.10) but there was little difference between corresponding authors from other African countries and corresponding authors from countries outside Africa. The importance of a study to Africa was independently associated with having more non-African authors (OR per author = 1.31; 95% CI = 1.08–1.58), fewer trial sites (OR per site = 0.69; 95% CI = 0.50–0.96), and reporting of funding (OR = 2.14; 95% CI = 1.15–4.00). Similar patterns were present in the comparisons of trials studying diseases important to Africa versus those studying diseases important to developed countries with stronger associations overall. When funding was reported, private industry funding was negatively associated with African importance compared with global importance (OR = 0.31, P = 0.008 for African importance and OR = 0.51, P = 0.57 for importance for developed countries). CONCLUSION: The relevance to Africa of trials conducted in Africa was not adversely affected by collaboration with non-African researchers but funding from private industry was associated with a decreased emphasis on diseases relevant to Afric
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