1,720,953 research outputs found
Vascular dementia and failure of intramural periarterial drainage – the role of the dystrophin associated protein complex
No full textIntroduction: Cerebral small vessel disease (CSVD), a key aspect of vascular dementia (VaD), consists of pathological modifications to cerebral vessel walls and associated white matter lesions. Cerebral vessels have a dual function: perfusion of the brain and drainage of interstitial fluid and solutes along the walls of capillaries and arteries as Intramural Periarterial Drainage (IPAD). IPAD fails with age resulting in cerebral amyloid angiopathy (CAA), part of the spectrum of CSVD. Most animal models designed to study CAA are modified to overexpress amyloid proteins, but this is in contrast to the majority of CAA cases which occur due to a failure of clearance of soluble amyloid, rather than genetic mutations. The conduit for IPAD is the capillary and arterial basement membrane. This basement membrane is synthesised by cells of the vessel wall and its modification leads to a failure of IPAD and CAA. Polarised astrocytic extensions form end feet projections that encircle the abluminal side of the vessel wall attaching to basement membrane by the dystrophin associated protein complex (DPC), of which alpha dystrobrevin (α-DB) and aquaporin 4 (AQP4) are key components. Alterations to this complex disrupt the morphology of vessel walls, causing abnormalities to basement membranes and altering blood-brain barrier function.This thesis aims to investigate the role of the DPC in the morphology and dynamics of IPAD pathways and to ascertain if mice with altered DPC can be used to model: 1) a failure of ISF fluid clearance by IPAD and 2) the features of CSVD and VaD. The following hypothesis are tested: 1) In mice that do not express glial AQP4 the morphology of capillary IPAD pathways is altered; 2) In mice genetically modifiedfor α-DB, the morphology and dynamics of IPAD pathways and cerebral perfusion are impaired.Methods: A detailed morphological study on the capillary wall from the white and grey matter in AQP4 and α-DB deficient mice was performed using quantitative electron microscopy and immunohistochemistry for collagen IV. The pattern of IPAD in white and grey matter was imaged and quantitatively measured in α-DB deficient and wild-type control mice. Cerebral perfusion under resting state and when challenged with hypercapnia was measured in α-DB deficient mice.Results: 1) AQP4 deficient mice showed a reduction in the percentage surface area of basement membranes and an increase in the percentage surface area of intramural cells in the white matter. 2) In α-DB deficient mice, the percentage surface area occupied by basement membrane was increased in capillary walls in both grey and white matter, accompanied by an increased expression of collagen IV in the grey matter. 3) The pattern of IPAD in the grey matter of α-DB deficient mice showed fewer arterioles with fluorescent soluble Aβ in their walls compared to age matched controls. 4) Solutes from the normal white matter drain preferentially along the basement membranes of capillaries. 5) Absence of α-DB is associated with a normal perfusion but a lower capacity for adaptation to hypercapnia.Conclusions. The results highlight an important role for α-DB and the DPC in maintaining the structural integrity of basement membranes, which is reflected in the capacity for draining interstitial fluid and solutes via IPAD. The localisation of AQP4 to astrocyte endfeet by its indirect association with α-DB and the DPC is not critical for the morphology of the basement membrane in the grey matter. As the capillary walls in the grey matter appear normal and the intramural cells in the white matter are enlarged, in contrast to the findings in human disease, AQP4 deficient mice do not replicate features of CSVD and may not be a suitable model for mechanistic insights into CSVD or VaD. Since this work highlighted that IPAD occurs preferentially along the capillary walls in the normal white matter with little involvement from arteries, it is important to consider the failure of IPAD as a key mechanistic feature of white matter hyperintensities. It remains to be seen if there are changes to α-DB and the DPC in the spectrum of CSVD in human brains, as this work points to it as a suitable model for further hypothesis-based studies of CSVD
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
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
- …
