1,720,962 research outputs found
Cerebral mechanisms of breathlessness and its relief
Get PDFThe perception of clinical breathlessness is a complex experience, modulated by physical and psychological factors. Distinguishable types of breathlessness arising from different peripheral mechanisms have been delineated, experimental models of these specific types have been developed and advances have been made in multidimensional assessments. However, current knowledge about cerebral mechanisms of breathlessness is lacking. Functional brain imaging studies have identified involvement of certain cortical structures but interpretations of these data are limited by various assumptions.
Aim:The primary purpose of this thesis was to interrogate the validity of the conclusions drawn by recent brain imaging studies and to draw further inferences about cerebral mechanisms of dyspnoea from neurological patients undergoing deep brain stimulation (DBS) for relief of other symptoms. Focusing on experimentally induced ‘air hunger’ (the most unpleasant form of clinical breathlessness) two primary working hypotheses were generated: (i) Perceptual sensitivity to experimentally induced breathlessness will be greater during MRI brain scans due to greater anxiety associated with the MRI milieu (ii) DBS of motor-thalamic nuclei generates breathlessness
Method:(i) Experimental breathlessness was induced in healthy subjects in simulated brain scanners to measure the effects of psychological stress associated with the functional magnetic resonance imaging (fMRI) scanner. (ii) Experimental breathlessness was induced in patients with DBS of the ventral intermediate (VIM) and ventralis oralisposterior (VOP) nuclei of the thalamus when the implanted electrodes are activated(switched ‘ON’ to stimulate the brain tissue) and when they are not activated (switched ‘OFF’ to stop stimulating the brain tissue).The Dyspnoea-12 multidimensional tool was also used to assess breathlessness. (iii)Probabilistic tractography was used to estimate the white fibre connectivity from the seed area (VIM) in the brain to brain regions of interest and to compare these in patients who responded differently in (ii).
Results: (i) Healthy volunteers with anxiety scores at or above average levels increased air hunger sensitivity in the simulated fMRI environment whereas those with low anxiety responded in the opposite direction. (ii) Contrary to the hypothesis posed, motorThalamic DBS resulted in relief of air hunger in all but one of the 6 patients studied. (iii) Tractography suggested that those patients who improved with DBS ‘ON’ had stronger connections to the anterior parts of the brain (orbitofrontal cortex) in contrast to the stronger connectivity to the posterior areas of the brain in the one patient who improved with DBS ‘OFF’.
Conclusion :( i) Future functional brain imaging studies of breathlessness should screen healthy volunteers for anxiety in order to improve interpretation of activations detected. (ii) Neurological patients undergoing DBS provide a useful clinical model to explore cerebral mechanisms of breathlessness. While the dataare largely inconclusive due to limited numbers of patients, the orbitofrontal connections for dyspnoea relief has been flagged as being an important element of a cerebral network for dyspnoea. Potential new thalamic targets for dyspnoea relief are suggested. The novel findings of this study lay the groundwork for better understanding of cerebral mechanisms of dyspnoea and therefore potential new and more effective targets for relief of intractable dyspnoea – a goal that remains an urgent clinical need
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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