1,720,955 research outputs found
Personal exposures of children to nitrogen dioxide relative to concentrations in outdoor air
No full textObjectives: To investigate the relation between fluctuations in personal exposure to nitrogen dioxide (NO2) in school children and changes in outdoor NO2 concentrations.Methods: 114 Asthmatic school children aged 7-12 years were recruited from the Southampton area. Weekly average personal exposures to NO2 were measured over a 13 month period with passive diffusion tubes. At the same time, outdoor NO2 concentrations were monitored at a fixed site in the centre of Southampton. Correlations between weekly personal exposures and mean outdoor concentrations during the same periods were examined.Results: Mean duration of follow up was 32 weeks. Measurements of weekly mean personal NO2 exposures were generally low and ranged from 0.7 to 496 µg/m3 with a geometric mean of 17 µg/m3. Substantial variation in personal exposures occurred between children and more especially within individual children from week to week. Daily outdoor concentrations of NO2 ranged from 4.3 to 29.8 µg/m3, with a geometric mean of 12.3 µg/m3. There was no evidence of seasonal variation in outdoor concentrations. No significant correlation was found between each child's weekly mean personal exposures to NO2 and mean outdoor concentrations for the corresponding periods.Conclusion: At low outdoor NO2 concentrations, fluctuations in NO2 in outdoor air as measured at a central monitoring station do not contribute importantly to variations in personal exposure when averaged over a week
Personal exposure to nitrogen dioxide (NO2) and the severity of virus-induced asthma in children
No full textBackground: A link between exposure to the air pollutant nitrogen dioxide (NO2) and respiratory disease has been suggested. Viral infections are the major cause of asthma exacerbations. We aimed to assess whether there is a relation between NO2 exposure and the severity of asthma exacerbations caused by proven respiratory viral infections in children.Methods: A cohort of 114 asthmatic children aged between 8 and 11 years recorded daily upper and lower respiratory-tract symptoms, peak expiratory flow (PEF), and measured personal NO2 exposures every week for up to 13 months. We took nasal aspirates during reported episodes of upper respiratory-tract illness and tested for infection by common respiratory viruses and atypical bacteria with RT-PCR assays. We used generalised estimating equations to assess the relation between low (<7·5 ?g/m3), medium (7·5–14 ?g/m3), and high (>14 ?g/m3) tertiles of NO2 exposure in the week before or after upper respiratory-tract infection and the severity of asthma exacerbation in the week after the start of an infection.Findings: One or more viruses were detected in 78% of reported infection episodes, and the medians of NO2 exposure were 5 (IQR 3·6–6·3), 10 (8·7–12·0), and 21 ?g/m3 (16·8–42·9) for low, medium, and high tertiles, respectively. There were significant increases in the severity of lower respiratory-tract symptom scores across the three tertiles (0·6 for all viruses [p=0·05] and >2 for respiratory syncytial virus [p=0·01]) and a reduction in PEF of more than 12 L/min for picornavirus (p=0·04) for high compared with low NO2 exposure before the start of the virus-induced exacerbation.Interpretation: High exposure to NO2 in the week before the start of a respiratory viral infection, and at levels within current air quality standards, is associated with an increase in the severity of a resulting asthma exacerbation
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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