1,720,953 research outputs found
Acute cardiovascular effects of exposure to air pollution: components, vascular mechanisms and protecting the public
Get PDFExposure to air pollution, particularly fine and ultrafine particulate matter
derived from combustion sources, has been consistently associated with
increased cardiovascular morbidity and mortality. Recent controlled
exposure studies demonstrate that short-term exposure to diesel exhaust,
which can contribute up to 40% of urban particulate air pollution, results in
impaired vascular endothelial and fibrinolytic function in healthy volunteers,
and increased exercise-induced myocardial ischaemia in patients with
coronary heart disease. These observations may, in part, explain the
observed increase in cardiovascular events following exposure to air
pollution.
Despite these observations there remain uncertainties regarding the key
constituents of the air pollution mixture that mediate these adverse effects,
and the underlying physiological and biological pathways involved. In these
studies, using two controlled exposure facilities, I explored the vascular
effects of the most prevalent gaseous component of the air pollution mixture
– nitrogen dioxide – and the mechanisms responsible for impaired
vasomotor function following exposure to diesel exhaust. Furthermore, I
investigated the effect of acute exposure to “real-world” urban air pollution
in both healthy volunteers and patients with coronary heart disease, and the
effect of reducing that exposure using a simple facemask. In total, 10 healthy volunteers were exposed to nitrogen dioxide, and 29
healthy volunteers exposed to dilute diesel exhaust in a series of doubleblind
randomised crossover studies. Exposure to nitrogen dioxide had no
effect on either vasomotor function or endogenous fibrinolysis, providing
indirect evidence that the adverse vascular effects are predominantly driven
by particulate components. Following exposure to diesel exhaust there was
no up regulation of endothelin-1 production, although there was increased
vasoconstriction to intra-arterial infusion of endothelin-1. Following
endothelin A receptor antagonism, there was attenuated vasodilatation
following exposure to diesel exhaust as compared to air, an effect abrogated
by endothelin B receptor antagonism. My findings suggest that the
endothelin system does not play a central role in the adverse vascular effects
of air pollution, but given the tonic interaction between the endothelin and
nitric oxide systems, these observations could be explained by reduced nitric
oxide bioavailability. Following diesel exhaust inhalation, plasma nitrite
concentrations (as a marker for nitric oxide generation) are markedly
increased without changes in haemodynamics or basal blood flow consistent
with increased nitric oxide consumption. In the presence of a nitric oxide
clamp, and without endogenous nitric oxide release, the vascular responses
to vasodilators are similar. This perturbation of nitric oxide consumption and
release appears to underlie the observed vascular endothelial effects. Fifteen healthy volunteers and 98 patients with coronary artery disease were
recruited in Beijing, China. Subjects walked along a predefined city centre
route for 2 hours in the presence and absence of a highly efficient facemask
to reduce personal particulate air pollution exposure in an open label
randomised crossover study. When wearing a facemask, there was an
attenuation of exercise-induced increases in blood pressure, an improvement
in heart rate variability, reduced myocardial ischaemia and subjects reported
fewer symptoms. My findings have identified the biological mechanisms underlying the
adverse vascular effects of exposure to diesel exhaust, and have helped to
clarify the components responsible for these effects. Moreover, I have
identified important benefits of reducing personal exposure to particulate
matter using a simple facemask that have the potential to reduce
cardiovascular events in patients living in urban or industrialised areas.
Ongoing research in this area will provide further insight into the underlying
vascular mechanisms, and the potential benefits of reducing particulate air
pollution exposure, and may result in important targeted interventions to
reduce the impact of air pollution on cardiovascular health
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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