1,720,981 research outputs found
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
Morcelised Impacted Cortico-Cancellous Bone Allografts in Revision Surgery for Endoprosthetic Loosening with Osteolysis
No full textRevision total hip arthroplasty (RTHA) and filling of the bone defects with impacted particulated bone allograft is the concept that has been studied in this thesis. In three in vitro models, biomechanical aspects of morcelised and impacted bone allografts were studied. The recoil of an impacted graft bed (as the impaction device was released) was found to be substantial (11-34 %). The clinical implication of this is that the space for a cement mantle may disappear. The recoil was higher using smaller bone chips and using higher compaction pressure. Higher initial impaction energy was found to create a more stable graft bed, which also was the case for larger bone chips. The rotational stability for a cup cemented on an impacted graft bed was doubled when using larger chips compared to smaller. When the larger chips were defatted, the stability was doubled again. Clinical and radiological results after revision total hip arthroplasty using impaction grafting was studied for Charnley and Lubinus prosthesis after a mean follow-up 64 months. The clinical results were good for both groups. Minor subsidence of the femoral stem occurred in a few RTHA in both groups. Mechanical failure was four per cent in both groups. A surgical method for revision total knee arthroplasty with impaction grafting was demonstrated. The clinical and radiological medium term results were good. Morphological outcome in biopsies was studied from 20 patients with impaction bone grafting. One month after RTHA a fibrous stroma and some newly formed trabecular bone was found. In-growth of living bone was almost complete after 48 months. Positron Emission Tomography (PET) was used to evaluate the metabolic events taking place after impaction bone grafting. Already eight days after surgery there was a high activity inside the graft beds indicating neovascularisation and active calcium metabolism. After one year this activity had diminished.</p
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
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