1,721,026 research outputs found
Transcranial pulsed Doppler in the diagnosis of cerebrovascular pathology: methodology, indications and limitations
No full textDoppler analysis of flow in intracranial arteries is now possible using a 2 MHz probe, allowing sufficient penetration of bone to obtain signals noninvasively and to measure rate of flow in middle (MCA), anterior (ACA) and posterior (PCA) cerebral arteries and in basilar trunk. Practical applications of this new method are numerous in cerebrovascular disease and, despite certain limitations due to anatomic factors, transcranial Doppler may identify stenosis of the intracranial arteries and study the value of collateral flow across the anterior circle of Willis in patients with extracranial carotid artery stenosis
A subclavian vein lesion due to the positioning of a chest tube via thoracostomy
No full textThe authors describe an unusual complication of chest tube placement: subclavian vein lesion. After a literature review concerning complications of chest tube placement, the authors conclude that associated risks may be best minimized with a strict adherence to standardized technique and management protocol
An unusual case of a double location of arteriosclerotic aneurysms of the ulnar artery and anterior tibial artery
No full textMultiple peripheral arteriosclerotic aneurysms are relatively rare. This is a report of a case of two arteriosclerotic aneurysms in unusual sites: ulnar artery and anterior tibial artery. Surgical treatment was: simple resection for the ulnar aneurysm; resection with restoration of arterial continuity for the tibial aneurysm
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
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