Performance of wide-area power system stabilizers during major system upsets: investigation and proposal of solutions

© 2021 Springer Nature Switzerland AG. This is a post-peer-review, pre-copyedit version of Benasla, M., Denaï, M., Liang, J. et al. Performance of wide-area power system stabilizers during major system upsets: investigation and proposal of solutions. Electr Eng (2021). The final authenticated version is available online https://doi.org/10.1007/s00202-020-01168-3Wide-area damping controllers (WADCs) are effective means of improving the damping of inter-area oscillations and thereby ensuring a secure operation of modern highly stressed interconnected power systems; however, their implementation costs are high. Therefore, the controller must be well configured and designed to ensure its cost-effectiveness. Several techniques have been proposed in the literature to design effective controllers and good results have been achieved. However, some important practical aspects that could potentially impact the performance of the designed controller have not been addressed or studied in sufficient detail in these previous works. One such aspect is assessing the performance of the designed controllers under major system upsets resulting in large deviations in the frequency and fluctuations in the power. These may lead to controller saturation which could negatively impact its damping performance or even cause instability. In this paper, the impact of such large upsets is investigated on several test systems via extensive small- and large-signal analyses and it is shown that, during severe transients, controller saturation may occur and persist over a long period of time, posing a potential threat to the power system stability. This paper presents a very effective solution to alleviate this problem and help design more robust WADCs. The simulation results show that the proposed solution works well and leads to improved power system stabilisers performance during transient upsets.Peer reviewedFinal Accepted Versio

Asthma prescribing, ethnicity and risk of hospital admission: an analysis of 35,864 linked primary and secondary care records in East London

This work was partly supported by funding from the Asthma UK Centre for Applied Research

Adolescents' experiences of being food-hypersensitive: a qualitative study

<p>Abstract</p> <p>Background</p> <p>Experiencing or being at risk of adverse reactions to certain food items is a common health issue, especially among children and adolescents. Research has shown that living with the risk of food reactions and always having to take measures to avoid certain food in one's diet has a negative impact on quality of life. The aim of this study was to illuminate adolescents' experiences of being food hypersensitive.</p> <p>Methods</p> <p>Three focus group interviews and six individual interviews were carried out with all together 17 adolescents, 14–18 years of age, who had exclusion diets at school due to food hypersensitivity. The interviews were taped and transcribed verbatim and a qualitative content analysis was carried out.</p> <p>Results</p> <p>Five categories with subcategories, and one pervading theme, emerged. The categories were: <it>Perceiving oneself as being particular</it>, <it>Feeling constrained</it>, <it>Experiencing others' ignorance</it>, <it>Keeping control</it>, and <it>Feeling it's okay</it>. A pervading theme was conceptualised as <it>Striving to normalise the experience of being food-hypersensitive</it>. The adolescents regarded themselves as competent and courageous, but also described how they avoided the extra attention it implied to ask for special food considerations taken into account. Their self-conceptions were probably essential for their management of and attitude toward the hypersensitivity condition. They felt deprived, and those at risk of severe food reactions experienced insecurity and fear. Feelings of being disregarded were expressed, as well as facing unreliability and a lack of understanding from others. The continual work of constant vigilance and decision-making was described as time-consuming and frustrating. However, the adolescents also experienced considerate and supportive surroundings and were at pains to tone down the negative experiences and consequences of being food-hypersensitive.</p> <p>Conclusion</p> <p>Food avoidance by itself, and not only the somatic food reactions, brings about consequences with significant impacts on adolescents' lives. The findings from this study have implications for all of those who deal with adolescents who are food-hypersensitive, and not only health professionals. A deeper insight into adolescents' experiences gives an understanding which can improve the care-givers' efforts.</p

Food allergy knowledge, attitudes and beliefs: Focus groups of parents, physicians and the general public

<p>Abstract</p> <p>Background</p> <p>Food allergy prevalence is increasing in US children. Presently, the primary means of preventing potentially fatal reactions are avoidance of allergens, prompt recognition of food allergy reactions, and knowledge about food allergy reaction treatments. Focus groups were held as a preliminary step in the development of validated survey instruments to assess food allergy knowledge, attitudes, and beliefs of parents, physicians, and the general public.</p> <p>Methods</p> <p>Eight focus groups were conducted between January and July of 2006 in the Chicago area with parents of children with food allergy (3 groups), physicians (3 groups), and the general public (2 groups). A constant comparative method was used to identify the emerging themes which were then grouped into key domains of food allergy knowledge, attitudes, and beliefs.</p> <p>Results</p> <p>Parents of children with food allergy had solid fundamental knowledge but had concerns about primary care physicians' knowledge of food allergy, diagnostic approaches, and treatment practices. The considerable impact of children's food allergies on familial quality of life was articulated. Physicians had good basic knowledge of food allergy but differed in their approach to diagnosis and advice about starting solids and breastfeeding. The general public had wide variation in knowledge about food allergy with many misconceptions of key concepts related to prevalence, definition, and triggers of food allergy.</p> <p>Conclusion</p> <p>Appreciable food allergy knowledge gaps exist, especially among physicians and the general public. The quality of life for children with food allergy and their families is significantly affected.</p

Assessment of pediatric asthma drug use in three European countries; a TEDDY study.

Asthma drugs are amongst the most frequently used drugs in childhood, but international comparisons on type and indication of use are lacking. The aim of this study was to describe asthma drug use in children with and without asthma in the Netherlands (NL), Italy (IT), and the United Kingdom (UK). We conducted a retrospective analysis of outpatient medical records of children 0-18 years from 1 January 2000 until 31 December 2005. For all children, prescription rates of asthma drugs were studied by country, age, asthma diagnosis, and off-label status. One-year prevalence rates were calculated per 100 children per patient-year (PY). The cohort consisted of 671,831 children of whom 49,442 had been diagnosed with asthma at any time during follow-up. ß2-mimetics and inhaled steroids were the most frequently prescribed asthma drug classes in NL (4.9 and 4.1/100 PY), the UK (8.7 and 5.3/100 PY) and IT (7.2 and 16.2/100 PY), respectively. Xanthines, anticholinergics, leukotriene receptor antagonists, and anti-allergics were prescribed in less than one child per 100 per year. In patients without asthma, ß2-mimetics were used most frequently. Country differences were highest for steroids, (Italy highest), and for ß2-mimetics (the UK highest). Off-label use was low, and most pronounced for ß2-mimetics in children <18 months (IT) and combined ß2-mimetics + anticholinergics in children <6 years (NL). CONCLUSION: This study shows that among all asthma drugs, ß2-mimetics and inhaled steroids are most often used, also in children without asthma, and with large variability between countries. Linking multi-country databases allows us to study country specific pediatric drug use in a systematic manner without being hampered by methodological differences. This study underlines the potency of healthcare databases in rapidly providing data on pediatric drug use and possibly safety

Health-related quality of life in food hypersensitive schoolchildren and their families: parents' perceptions

BACKGROUND: About 20% of schoolchildren and adolescents in Sweden suffer from perceived food hypersensitivity (e.g. allergy or intolerance). Our knowledge of how child food hypersensitivity affects parents HRQL and what aspects of the hypersensitivity condition relate to HRQL deterioration in the family is limited. Thus the aim of this study was to investigate the parent-reported HRQL in families with a schoolchild considered to be food hypersensitive. The allergy-associated parameters we operated with were number of offending food items, adverse food reactions, additional hypersensitivity, allergic diseases and additional family members with food hypersensitivity. These parameters, along with age and gender were assessed in relation to child, parent and family HRQL. METHODS: In May 2004, a postal questionnaire was distributed to parents of 220 schoolchildren with parent-reported food hypersensitivity (response rate 74%). Two questionnaires were used: CHQ-PF28 and a study-specific questionnaire including questions on allergy-associated parameters. In order to find factors that predict impact on HRQL, stepwise multiple linear regression analyses were carried out. RESULTS: An important predictor of low HRQL was allergic disease (i.e. asthma, eczema, rhino conjunctivitis) in addition to food hypersensitivity. The higher the number of allergic diseases, the lower the physical HRQL for the child, the lower the parental HRQL and the more disruption in family activities. Male gender predicted lower physical HRQL than female gender. If the child had sibling(s) with food hypersensitivity this predicted lower psychosocial HRQL for the child and lower parental HRQL. Food-induced gastro-intestinal symptoms predicted lower parental HRQL while food-induced breathing difficulties predicted higher psychosocial HRQL for the child and enhanced HRQL with regards to the family's ability to get along. CONCLUSION: The variance in the child's physical HRQL was to a considerable extent explained by the presence of allergic disease. However, food hypersensitivity by itself was associated with deterioration of child's psychosocial HRQL, regardless of additional allergic disease. The results suggest that it is rather the risk of food reactions and measures to avoid them that are associated with lower HRQL than the clinical reactivity induced by food intake. Therefore, food hypersensitivity must be considered to have a strong psychosocial impact

Development and Disease: How Susceptibility to an Emerging Pathogen Changes through Anuran Development

Ranaviruses have caused die-offs of amphibians across the globe. In North America, these pathogens cause more amphibian mortality events than any other pathogen. Field observations suggest that ranavirus epizootics in amphibian communities are common during metamorphosis, presumably due to changes in immune function. However, few controlled studies have compared the relative susceptibility of amphibians to ranaviruses across life stages. Our objectives were to measure differences in mortality and infection prevalence following exposure to ranavirus at four developmental stages and determine whether the differences were consistent among seven anuran species. Based on previous studies, we hypothesized that susceptibility to ranavirus would be greatest at metamorphosis. Our results did not support this hypothesis, as four of the species were most susceptible to ranavirus during the larval or hatchling stages. The embryo stage had the lowest susceptibility among species probably due to the protective membranous layers of the egg. Our results indicate that generalizations should be made cautiously about patterns of susceptibility to ranaviruses among amphibian developmental stages and species. Further, if early developmental stages of amphibians are susceptible to ranaviruses, the impact of ranavirus epizootic events may be greater than realized due to the greater difficulty of detecting morbid hatchlings and larvae compared to metamorphs

Role of Sphingomyelin Synthase in Controlling the Antimicrobial Activity of Neutrophils against Cryptococcus neoformans

The key host cellular pathway(s) necessary to control the infection caused by inhalation of the environmental fungal pathogen Cryptococcus neoformans are still largely unknown. Here we have identified that the sphingolipid pathway in neutrophils is required for them to exert their killing activity on the fungus. In particular, using both pharmacological and genetic approaches, we show that inhibition of sphingomyelin synthase (SMS) activity profoundly impairs the killing ability of neutrophils by preventing the extracellular release of an antifungal factor(s). We next found that inhibition of protein kinase D (PKD), which controls vesicular sorting and secretion and is regulated by diacylglycerol (DAG) produced by SMS, totally blocks the extracellular killing activity of neutrophils against C. neoformans. The expression of SMS genes, SMS activity and the levels of the lipids regulated by SMS (namely sphingomyelin (SM) and DAG) are up-regulated during neutrophil differentiation. Finally, tissue imaging of lungs infected with C. neoformans using matrix-assisted laser desorption-ionization mass spectrometry (MALDI-MS), revealed that specific SM species are associated with neutrophil infiltration at the site of the infection. This study establishes a key role for SMS in the regulation of the killing activity of neutrophils against C. neoformans through a DAG-PKD dependent mechanism, and provides, for the first time, new insights into the protective role of host sphingolipids against a fungal infection