ORCID Profile
0000-0002-1994-4023
Current Organisation
The University of Auckland
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Publisher: European Respiratory Society (ERS)
Date: 10-02-2022
DOI: 10.1183/13993003.02866-2021
Abstract: There have been no worldwide standardised surveys of prevalence and severity of asthma, rhinoconjunctivitis and eczema in school children for 15 years. The present study aims to provide this information. Following the exact International Study of Asthma and Allergies in Childhood (ISAAC) methodology (cross-sectional questionnaire-based survey), Global Asthma Network (GAN) Phase I was carried out between 2015 and 2020 in many centres worldwide. The study included 157 784 adolescents (13–14 years of age) in 63 centres in 25 countries and 101 777 children (6–7 years of age) in 44 centres in 16 countries. The current prevalence of symptoms, respectively, was 11.0% and 9.1% for asthma, 13.3% and 7.7% for rhinoconjunctivitis and 6.4% and 5.9% for eczema. The prevalence of asthma ever was 10.5% and 7.6%, hay fever ever was 15.2% and 11.1% and eczema ever was 10.6% and 13.4%, respectively. Centres in low or lower middle gross national income countries (LICs or LMICs) had significantly lower prevalence of the three disease symptoms and diagnoses (except for hay fever). In children, the prevalence of asthma and rhinoconjunctivitis symptoms was higher in boys, while the reverse occurred among adolescents. For eczema, while the prevalence among female adolescents was double that of males, there was no sex difference among children. Centre accounted for non-negligible variability in all disease symptoms (10–20%). The burdens of asthma, rhinoconjunctivitis and eczema vary widely among the limited number of countries studied. Although symptom prevalence is lower in LICs and LMICs, it represents a considerable burden everywhere studied.
Publisher: AIP Publishing
Date: 05-10-2020
DOI: 10.1063/5.0012883
Abstract: Solid-state qubits integrated on semiconductor substrates currently require at least one wire from every qubit to the control electronics, leading to a so-called wiring bottleneck for scaling. Demultiplexing via on-chip circuitry offers an effective strategy to overcome this bottleneck. In the case of gate-defined quantum dot arrays, specific static voltages need to be applied to many gates simultaneously to realize electron confinement. When a charge-locking structure is placed between the quantum device and the demultiplexer, the voltage can be maintained locally. In this study, we implement a switched-capacitor circuit for charge-locking and use it to float the plunger gate of a single quantum dot. Parallel plate capacitors, transistors, and quantum dot devices are monolithically fabricated on a Si/SiGe-based substrate to avoid complex off-chip routing. We experimentally study the effects of the capacitor and transistor size on the voltage accuracy of the floating node. Furthermore, we demonstrate that the electrochemical potential of the quantum dot can follow a 100 Hz pulse signal while the dot is partially floating, which is essential for applying this strategy in qubit experiments.
Publisher: European Respiratory Society (ERS)
Date: 23-12-2016
DOI: 10.1183/13993003.01605-2016
Abstract: The Global Asthma Network (GAN), established in 2012, followed the International Study of Asthma and Allergies in Childhood (ISAAC). ISAAC Phase One involved over 700 000 adolescents and children from 156 centres in 56 countries it found marked worldwide variation in symptom prevalence of asthma, rhinitis and eczema that was not explained by the current understanding of these diseases ISAAC Phase Three involved over 1 187 496 adolescents and children (237 centres in 98 countries). It found that asthma symptom prevalence was increasing in many locations especially in low- and middle-income countries where severity was also high, and identified several environmental factors that required further investigation. GAN Phase I, described in this article, builds on the ISAAC findings by collecting further information on asthma, rhinitis and eczema prevalence, severity, diagnoses, asthma emergency room visits, hospital admissions, management and use of asthma essential medicines. The subjects will be the same age groups as ISAAC, and their parents. In this first global monitoring of asthma in children and adults since 2003, further evidence will be obtained to understand asthma, management practices and risk factors, leading to further recognition that asthma is an important non-communicable disease and to reduce its global burden.
Publisher: Oxford University Press (OUP)
Date: 02-1997
DOI: 10.1093/IJE/26.1.126
Abstract: To examine whether responses to questions about the lifetime prevalence and 12-month period prevalence of symptoms of asthma and allergies are affected by the season in which the questions are asked. The international Study of Asthma and Allergies in Childhood (ISAAC) Phase One was undertaken in six New Zealand centres in three centres the effect of season was studied. Over three school terms at least 3000 children were studied in each of two age groups per centre (6-7 years 13-14 years), one-third in each term respectively. The ISAAC standardized written questionnaires were used to identify asthma, rhinitis and eczema symptoms. The written questionnaire in the younger age group was completed by the parent/guardian. The older age group self-completed the written questionnaire and also a video questionnaire about asthma symptoms. The total number of respondents was 21,437, approximately half in each age group. The season of responding had no effect on the level of response to eczema questions. For the written asthma questionnaire no season-of-response effect was present for 6-7 year olds for 13-14 year olds there was a trend to a higher rate of positive responses by those responding in winter, but in only one question did this reach statistical significance. With the video questionnaire there was a similar trend for a higher rate of positive responses when questions were asked in winter, but this did not reach statistical significance. For rhinitis symptoms there was a statistically significant season-of-response effect in both age groups with two questions the fewest positive responses by the winter responders. There was no significant effect of season-of-response to questions on eczema symptoms, and most questions on asthma symptoms. There was a season-of-response effect on responses to questions on rhinitis symptoms suggesting a recall bias relating to recency of symptoms.
Publisher: European Respiratory Society (ERS)
Date: 24-02-2022
DOI: 10.1183/13993003.02865-2021
Abstract: Asthma, hay fever and eczema are three common chronic conditions. There have been no recent multi-country data on the burden of these three conditions in adults the aims of this study are to fill this evidence gap. The Global Asthma Network Phase I is a multi-country cross-sectional population-based study using the same core methodology as the International Study of Asthma and Allergies in Childhood Phase III. It provides data on the burden of asthma, hay fever and eczema in children and adolescents, and, for the first time, in their parents/guardians. Data were available from 193 912 adults (104 061 female mean± sd age 38±7.5 years) in 43 centres in 17 countries. The overall prevalence (range) of symptoms was 6.6% (0.9–32.7%) for current wheeze, 4.4% (0.9–29.0%) for asthma ever, 14.4% (2.8–45.7%) for hay fever ever and 9.9% (1.6–29.5%) for eczema ever. Centre prevalence varied considerably both between countries and within countries. There was a moderate correlation between hay fever ever and asthma ever, and between eczema ever and hay fever ever at the centre level. There were moderate to strong correlations between indicators of the burden of disease reported in adults and the two younger age groups. We found evidence for a substantial burden of asthma, hay fever ever and eczema ever in the countries examined, highlighting the major public health importance of these diseases. Prevention strategies and equitable access to effective and affordable treatments for these three conditions would help mitigate the avoidable morbidity they cause.
Publisher: Wiley
Date: 07-2009
DOI: 10.1016/J.OTOHNS.2009.03.007
Abstract: To determine the prevalence of allergic symptoms in children with otitis media with effusion (OME). A validated questionnaire from the International Study of Asthma and Allergies in Childhood was used to determine the prevalence of allergic symptoms in children. The questionnaire was completed by the parents of children with OME undergoing ventilation tube insertion, and the results were compared with a large reference group of school children of the same age. Children aged 6 or 7 years old with OME confirmed intraoperatively during ventilation tube insertion between 2001 and 2005 (n = 89). The prevalence of allergic symptoms and nasal symptoms in children with OME was compared with an age‐matched reference group. There was no difference in the prevalence of allergic symptoms suggesting rhinoconjunctivitis, asthma, or eczema between the OME and reference group. The prevalence of nasal symptoms, however, was greater in the children with OME than in the reference group 38.2 percent versus 23.5 percent (odds ratio = 2.01 95% confidence interval, 1.30‐3.10 P 0.001). The prevalence of allergic symptoms was similar in 6‐ to 7‐year‐old children with OME and the reference group, suggesting a limited effect of allergy in the pathogenesis of OME in this age group. Nasal symptoms were more common in the OME group, which may reflect a higher prevalence of adenoidal hyperplasia.
Publisher: Wiley
Date: 2004
DOI: 10.1002/PPUL.10449
Abstract: The International Study of Asthma and Allergies in Childhood (ISAAC) demonstrated that the highest prevalence of asthma in the world is in English-speaking countries, including New Zealand. In this paper, we compare asthma symptom prevalence in the three major ethnic groups (Maori, Pacific, and European) in the six participating centers in New Zealand. Hospital admission rates for asthma are higher among Maori and Pacific children compared to European children. The working hypothesis was that there were important differences in prevalence of asthma symptoms or diagnosis between ethnic groups which might explain these observed differences in asthma morbidity. In each center in 1992-1993, we s led approximately 3000 children at each of the age brackets 6-7 years and 13-14 years. There were 37592 participants. Maori children had higher rates of diagnosed asthma and reported asthma symptoms than Pacific children in both age groups (diagnosed asthma in 6-7-year-olds: Maori, 31.7% Pacific, 21.2% 95% confidence interval on difference (CID), 7.2, 13.8 P < 0.001 13-14-year-olds: Maori, 24.7% Pacific, 19.2% CID 2.5, 8.5 P < 0.001 recent wheeze in 6-7-year-olds: Maori, 27.6% Pacific, 22.0% CID, 2.6, 8.6 P < 0.001 13-14-year-olds: Maori, 30.8% Pacific, 21.1% CID, 4.8, 14.5 P < 0.001 ). European children had rates intermediate between those of Maori and Pacific children (6-7-year-olds) or similar to those of Maori children (13-14-year-olds), but had the lowest prevalence of night waking with wheeze in both age groups (e.g., 6-7-year-olds: European, 2.6% Maori, 5.8% Pacific, 5.7% European-Maori CID: -4.2, -2.2, P < 0.001 European-Pacific CID: -4.7, -1.7, P < 0.001 Maori-Pacific CID: -1.7, 1.8, P = 1.0). The pattern of differences closely resembled that in a 1985 Auckland study, despite a 1.5-1.7-fold overall increase in prevalence. In conclusion, there are important differences in asthma prevalence among Maori, Pacific, and European children. These differences are small compared to worldwide variation, but their pattern is stable over time. The higher rate of severe asthma symptoms that Maori and Pacific children report may be one reason for the increased asthma morbidity in these groups. Further studies are needed to determine the reasons for these apparent differences in asthma severity.
Publisher: AIP Publishing
Date: 21-08-2023
DOI: 10.1063/5.0160847
Abstract: Semiconductor spin qubits have gained increasing attention as a possible platform to host a fault-tolerant quantum computer. First demonstrations of spin qubit arrays have been shown in a wide variety of semiconductor materials. The highest performance for spin qubit logic has been realized in silicon, but scaling silicon quantum dot arrays in two dimensions has proven to be challenging. By taking advantage of high-quality heterostructures and carefully designed gate patterns, we are able to form a tunnel coupled 2 × 2 quantum dot array in a 28Si/SiGe heterostructure. We are able to load a single electron in all four quantum dots, thus reaching the (1,1,1,1) charge state. Furthermore, we characterize and control the tunnel coupling between all pairs of dots by measuring polarization lines over a wide range of barrier gate voltages. Tunnel couplings can be tuned from about 30 μeV up to approximately 400 μeV. These experiments provide insightful information on how to design 2D quantum dot arrays and constitute a first step toward the operation of spin qubits in 28Si/SiGe quantum dots in two dimensions.
No related grants have been discovered for Philippa Ellwood.