1,720,960 research outputs found

    Cerebral vascular reactivity and cognitive performance in patients with extracranial asymptomatic carotid stenosis

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    Background: Preliminary studies have reported cognitive dysfunction in unilateral asymptomatic carotid stenosis (ACS). Impaired cerebral hemodynamic status measured by cerebrovascular reactivity has been associated with cognitive dysfunction in unilateral ACS. Aims: (1) To evaluate cognitive performance in bilateral ACS compared to unilateral ACS and healthy subjects and (2) to explore the relationship between cognitive performance and cerebral hemodynamic status in bilateral ACS. Methods: Asymptomatic patients with ultrasound evidence of bilateral or unilateral ACS (60 %-99 % diameter reduction) were prospectively collected. Healthy subjects (HS) comparable for demographics and vascular risk profile served as controls. A neuropsychological investigation included phonemic and categorical Verbal Fluency (VF) tests to explore the left hemisphere and Colored Progressive Matrices (CPM), and Complex Figure Test Copy (CFTC) tests to explore the right hemisphere. Cerebrovascular reactivity (CVR) to hypercapnia using the transcranial Doppler (TCD) based breath-holding index (BHI) test was performed in each subject. Impaired CVR was defined as a BHI\0.69. Generalized linear multivariate and univariate models were employed to evaluate the mean difference on left and right cognitive test abilities in bilateral ACS patients with left and right preserved or impaired CVR. Vascular risk factors, education years, mini-mental status examination (MMSE), and current medications were included as covariates. Results: 333 consecutive subjects were included: 126 bilateral ACS; 73/75 left/right unilateral ACS; 56 HS; mean age: 70 ± 3.78 years; males: 65 %; education years: 10.3 ± 3.7; MMSE score: 26.7 ± 1.27. Bilateral and unilateral ACS patients showed significantly lower scores in all cognitive tests compared to HS (p\0.05). In the multivariate analysis, among bilateral ACS an impaired CVR in the right side was associated with a significantly reduced CPM score: from an estimated mean of 32.6 [95 % Confidence Interval (CI): 29.8–35.4) to 23.0 (95 % CI: 20.2–25.8) and the CFTC score from 34.7 (95 % CI: 32.0–37.4) to 26.0 (95 % CI: 23.3–28.7). Similarly, an impaired CVR on the left side was associated with a reduced phonemic VF score: 13.5 (95 % CI: 11.2–15.8) to 7.5 (95 % CI: 5.4–9.7) and categorical VF score from 21.1 (95 % CI: 18.1–24.1) to 12.3 (95 % CI: 9.5–15.1). All comparisons were statistically significant (p\0.05). Conclusions: Patients with unilateral or bilateral ACS are more likely to suffer cognitive dysfunction compared to healthy controls. Impaired CVR predicts the development of cognitive dysfunction in bilateral ACS. A non-invasive assessment of CVR using the TCDbased BHI test may contribute to a more comprehensive risk stratification in these patients

    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The 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

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    “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

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    We 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

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    We 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

    Author Index

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    koamabayili/VECTRON-author-checklist: VECTRON author checklist

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    We 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 Under Sail The Imagination of Jack London, 1893-1902

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    In 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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