Space charge accumulation under the effects of temperature gradient on solid dielectric DC cable

It is well known that existence and accumulation of space charge within the insulating material poses threat to the reliability in the operation of dc power cables. When the cables are loaded under high voltage direct current (HVDC), temperature gradient is developed across the insulation material. In this paper, commercial ac XLPE power cables were used under an application voltage of 80 kV dc with different temperature gradients loaded between the insulating material. Space charge distributions were then measured across the insulation of the cable by means of a modified pulsed electroacoustic (PEA) system with a current transformer attached. Therefore, a replica of a power cable under load conditions could be obtained, which allows us to investigate the formation, migration and accumulation of space charges in a power cable both without and with different temperature gradients consideration across the bulk of the insulating material. Discussion will be made thoroughly in order to understand the space charge phenomenon of power cable under its service temperature

Space Charge Accumulation under Effects of Temperature Gradient and Applied Voltage Reversal on Solid Dielectric DC Cable

A well-known fact of the existence and accumulation of space charge within the insulating material poses threat to the reliability in the operation of dc power cables. When power cables are loaded under high voltage direct current (HVDC), temperature gradient is developed across the insulation. Results of space charge evolution in commercial ac XLPE power cables under an application of 80 kV dc supply at different temperature gradients and during external voltage reversal are discussed in this paper. The space charge distributions were measured across the insulation of the cable by means of a modified pulsed electroacoustic (PEA) system with a current transformer attached. Therefore, a replica of a power cable under load conditions could be obtained, which allows us to investigate the formation, migration and accumulation of space charges in a power cable both without and with different temperature gradients consideration across the bulk of the insulating material during voltage reversal. Discussion will be made thoroughly in order to understand the space charge phenomenon of power cable under its service temperature as space charge accumulation during polarity reversal plays an important factor on the electric field distribution within the insulation material

Bedding covers for people with allergic rhinitis

A patient comes to you asking whether using a mattress cover would help her allergic rhinitis. You know that she is allergic to house-dust mites and you know also that bedding covers have been widely recommended for allergic rhinitis, not least by several clinical guidelines. You have also heard however that some doubt has been cast on the evidence supporting these recommendations. With your interest raised, you determine to try to find out for yourself.

The impact of chest radiography on the diagnosis, clinical management and outcome of acute lower respiratory infections in children

Background. When available, chest radiography is widely used in acute lower respiratory infections in children. Its impact on clinical outcome is unknown. Methods. A randomised controlled trial was performed of 522 children aged 2 to 59 months who met the World Health Organisation case definition for pneumonia. The main outcome was time to recovery, measured in a subset of 398 participants who offered a telephone number. Subsidiary outcomes included diagnosis, elements of clinical management and subsequent use of health facilities. Findings. There was a marginal improvement in time to recovery, which was not clinically significant. The median time to recovery was seven days in both groups, 95% CI 6-8 days and 6-9 days in the radiograph and control groups respectively (p=0.50, log rank test). The hazard ratio for recovery was 1.08 (95% CI 0.85 to 1.34). This lack of effect was not modified by clinicians' experience and no sub-groups of children were identified in whom the radiograph had an effect. Pneumonia was diagnosed more often in the radiograph group (14.4% vs. 8.8%, p=0.03) and bronchiolitis less often ( 44% vs. 56%, p=0.005). Antibiotic usage was higher in the radiograph group (60.8% vs. 52.2%, p=0,05). There were no differences in subsequent health facility usage. Interpretation. Despite a net change in diagnosis and an increase in antibiotic usage, chest radiography did not affect clinical outcome in outpatient children with acute lower respiratory infection. This lack of effect was independent of clinicians' experience. There were no clinically identifiable sub-groups of children within the World Health Organisation case definition of pneumonia who benefited from radiography. It is concluded that routine use of chest radiography is not beneficial in ambulatory children over two months of age with acute lower respiratory infection

The utility of computed tomography for recent-onset partial seizures in childhood

No Abstract. South African Medical Journal Vol. 96(9) (Part 2) 2006: 941-94

The utility of computed tomography for recent-onset partial seizures in childhood

Objectives. The objective was to evaluate the role of a paediatric surgical consultant at a primary health care facility. Design. Descriptive and prospective. Setting. In the process of planning and implementation of the 2010 health plan of the Provincial Government of the Western Cape, a shift occurred in the delivery of health care to children from a provincially based hospital system to a municipally based primary health care system. To contribute towards enabling this process, the Department of Paediatric Surgery at Red Cross War Memorial Children’s Hospital established a paediatric surgical day clinic at a local community health centre during 2001. Subjects. Information was obtained from patient data sheets containing details of consultations at the sub-specialist surgical clinic at Michael Mapongwana Community Health Centre. Results. Over a 58-month period 1 171 children were seen, of whom 655 were male and 427 female. Their ages ranged from 0 to 19 years, the largest group being under 1 year. Eighty per cent of patients were accompanied by their mothers. The correct diagnosis was established by the nurse practitioners in 71%. General paediatric surgical conditions predominated, followed by medical, dermatological, orthopaedic, trauma, otolaryngo-pharyngology, infectious diseases, ophthalmology, urology, neurosurgery, malignancy and maxillofacial conditions. The details are set out in the report. In total 597 patients were referred directly to an appropriate care facility and 574 patients could be managed entirely at the clinic level. Conclusions. This study demonstrated the significant public health problem of paediatric surgical disease. It emphasised the preventative and cost-effective role of a surgical clinic at primary health care level. The clinic allowed for timely surgical intervention in 65% of surgical cases, thereby decreasing inappropriate tertiary referrals. We believe that bringing specialists into the community can only strengthen the 2010 health care plan

Spatio-temporal evaluation of social media as a tool for livestock disease surveillance

Recent outbreaks of Avian Influenza across Europe have highlighted the potential for syndromic surveillance systems that consider other modes of data, namely social media. This study investigates the feasibility of using social media, primarily Twitter, to monitor illness outbreaks such as avian flu. Using temporal, geographical, and correlation analyses, we investigated the association between avian influenza tweets and officially verified cases in the United Kingdom in 2021 and 2022. Pearson correlation coefficient, bivariate Moran's I analysis and time series analysis, were among the methodologies used. The findings show a weak, statistically insignificant relationship between the number of tweets and confirmed cases in a temporal context, implying that relying simply on social media data for surveillance may be insufficient. The spatial analysis provided insights into the overlaps between confirmed cases and tweet locations, shedding light on regionally targeted interventions during outbreaks. Although social media can be useful for understanding public sentiment and concerns during outbreaks, it must be combined with traditional surveillance methods and official data sources for a more accurate and comprehensive approach. Improved data mining techniques and real-time analysis can improve outbreak detection and response even further. This study underscores the need of having a strong surveillance system in place to properly monitor and manage disease outbreaks and protect public health.</p

Text mining of veterinary forums for epidemiological surveillance supplementation

Web scraping and text mining are popular computer science methods deployed by public health researchers to augment traditional epidemiological surveillance. However, within veterinary disease surveillance, such techniques are still in the early stages of development and have not yet been fully utilised. This study presents an exploration into the utility of incorporating internet-based data to better understand smallholder farming communities within the UK, by using online text extraction and the subsequent mining of this data. Web scraping of the livestock fora was conducted, with text mining and topic modelling of data in search of common themes, words, and topics found within the text, in addition to temporal analysis through anomaly detection. Results revealed that some of the key areas in pig forum discussions included identification, age management, containment, and breeding and weaning practices. In discussions about poultry farming, a preference for free-range practices was expressed, along with a focus on feeding practices and addressing red mite infestations. Temporal topic modelling revealed an increase in conversations around pig containment and care, as well as poultry equipment maintenance. Moreover, anomaly detection was discovered to be particularly effective for tracking unusual spikes in forum activity, which may suggest new concerns or trends. Internet data can be a very effective tool in aiding traditional veterinary surveillance methods, but the requirement for human validation of said data is crucial. This opens avenues of research via the incorporation of other dynamic social media data, namely Twitter, in addition to location analysis to highlight spatial patterns

Methodological challenges in a study on falls in an older population of Cape Town, South Africa

Background: Falls are a major cause of disability, morbidity and mortality in older persons, but have been under researched in developing countries. .Objective: To describe challenges encountered in a community-based study on falls in a multi-ethnic population aged ≥65 years in a low-income setting.Methods: The study was conducted in four stages: A pilot study (n=105) to establish a sample size for the survey. An equipment validation study (n=118) to use for fall risk determination. A cross-sectional baseline (n=837) and a 12-month follow-up survey (n=632) to establish prevalence and risk factors for falls.Results: Prevalence rate of 26.4% (95% CI 23.5-29.5%) and risk factors for recurrent falls: previous falls, self-reported poor mobility and dizziness were established. Adaptations to the gold standard prospective fall research study design were employed: 1) to gain access to the study population in three selected suburbs, 2) to perform assessments in a non-standardised setting, 3) to address subjects’ poverty and low literacy levels, and high attrition of subjects and field workers.Conclusion: Studies on falls in the older population of low- to middle-income countries have methodological challenges. Adaptive strategies used in the Cape Town study and the research experience reported may be instructive for investigators planning similar studies in such settings.Keywords: Falls, older people, community-based research, low and middle income countries, methodology, study desig