1,721,026 research outputs found
Advanced imaging predicting outcome in stroke: therapeutic implications
No full text© 2015 Dr. Nawaf YassiIschaemic stroke is caused by sudden occlusion of a cerebral artery leading to infarction of brain tissue. Effective stroke treatment requires accurate diagnosis, and this is highly dependent on brain imaging. Modern advanced imaging in stroke provides useful diagnostic and prognostic information with implications for therapy across various stages of stroke evolution, from the hyperacute stage to recovery and rehabilitation. This thesis explores advanced imaging approaches for the prediction of stroke outcome. The first experimental study describes an evaluation of Computed Tomography Perfusion (CTP) in the early prediction of haemorrhagic transformation after stroke. This is based on previous work using MRI, which demonstrates that regions of very poor perfusion are associated with a risk of haemorrhagic transformation when reperfusion occurs. A similar application with CTP would be more widely accessible as this is usually the first modality used in investigating patients in the clinical setting. The volume of severely hypoperfused tissue (Tmax>14sec) on CTP is shown to be independently associated with parenchymal haematoma after ischaemic stroke, and this parameter outperforms CTP estimates of ischaemic core volume.
Imaging-based paradigms for the assessment of stroke prognosis have generally ignored the important question of infarct location. The second experimental study explores the association between infarct location and functional outcome in a pooled analysis of the EPITHET and DEFUSE trials. Using an automatable co-registration and segmentation methodology, posttreatment diffusion lesions are divided into brain regions. A Classification and Regression Tree approach is then used to explore important regions associated with poor functional outcome at 3-months.
Finally, results of a prospective imaging based study of ischaemic stroke recovery are presented. The Advanced Neuroimaging in Stroke Wellbeing and Recovery (ANSWER) study involved 20 stroke patients within 1-week of onset, and 20 controls. Patients were imaged with multimodal 3T-MRI within 1-week of onset, and at 1 and 3-months. Controls underwent an identical scan on a single occasion.
The first study from this cohort explores the use of early quantitative magnetic resonance spectroscopy in predicting brain tissue loss after stroke. It is shown that reductions in N-Acetylaspartic acid and total creatine are associated with subsequent white-matter atrophy in the infarct hemisphere between 1 and 3- months after stroke.
Methodological issues relating to this study and other stroke volumetric studies are evaluated with a systematic investigation of longitudinal brain volume measurement after stroke including an assessment of different analysis approaches. A modest agreement is demonstrated between methods, with significant disagreement caused by variable handling of infarct lesions, highlighting the importance of careful interpretation of results from post-stroke volumetric studies.
Finally, a study of contralesional subcortical volume change is presented, which is less prone to such methodological limitations. A significant reduction in contralesional thalamic volume is demonstrated in the first 3-months after stroke, and this is corroborated with an increasing functional disconnection between the contralesional thalamus and the remainder of the brain.
Advanced imaging provides valuable information during the early assessment of stroke pathophysiology, as well as providing prognostic information to guide rehabilitative therapy. A further potential application of such methods is as radiological biomarkers in the testing of putative neuroprotective or neurorestorative therapies
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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