1,720,974 research outputs found
Warfarin use and risk of osteoporotic fractures
No full textThesis (M.S.M.) PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at [email protected]. Thank you.OBJECTIVE: Prior studies examining the association of warfarin use and osteoporotic fractures have found conflicting results and have had methodological problems, such as confounding by indication and confounding by duration of warfarin use. Thus, we studied the association of warfarin use with fractures at the hip, spine and wrist, among older men and women with atrial fibrillation recruited from the general population, using rigorous statistical tools to overcome challenges faced by prior studies.
METHODS: We included men and women ≥65 years with incident atrial fibrillation, without history of fracture, followed between 2000-2010 from The Health Improvement Network (THIN). Long-term warfarin use was defined in two ways: 1) warfarin use ≥ 1year; 2) warfarin use ≥3 years. Non-use was defined as no use of warfarin over the follow-up period. Propensity scores (PS) for warfarin use were calculated using logistic regression with long-term use of warfarin as the dependent variable and age, sex, body mass index (BMI), history of multiple falls, deep venous thrombosis, pulmonary embolism, heart failure, neuropsychiatric impairment, hyperthyroidism, estrogen use, beta blockers, corticosteroids, bisphosphonates, smoking and alcoholism as independent variables. Each warfarin user was then matched by PS to a non-user by the “greedy matching” method. Incidence rates were calculated for warfarin users and non-users. The association between long-term warfarin use and risk of hip, spine and wrist fractures was evaluated using Cox-proportional hazards models.
RESULTS: Incidence rates of hip fracture were 5.21 and 6.20 per 1000 person-years among subjects with warfarin use >1 (n=20,346) and >3 (n=11,238) years, respectively. The hazard ratios of hip fracture for warfarin use >1 and >3 years were 1.08 (95% CI 0.87, 1.35) and 1.13 (95% CI: 0.84, 1.5), respectively. Similar findings were observed between warfarin use and risk of spine or wrist fracture.
CONCLUSIONS: Long-term use of warfarin among older adults with atrial fibrillation is not associated with increased risk of osteoporotic fractures and thus, does not necessitate additional surveillance or prophylaxis.2031-01-0
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
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