1,720,966 research outputs found
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
Developing a Collagen III Targeted MRI Probe for Molecular Imaging of Cardiac Fibrosis
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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
BS43 A new collagen III-specific MRI imaging probe to assess cardiac fibrosis
Full text linkHeart failure (HF) has reached epidemic proportions, affecting approximately 64 million people globally and is the main cause of death and disability.1 Myocardial fibrosis, characterised by changes in the amount and/or distribution of collagen I and III, impairs cardiac function and relates to adverse outcomes of HF.2 3 Clinically, we rely on indirect or surrogate measurements of collagen in the myocardium and current targeted molecular imaging probes are limited to collagen I. Here, we report the discovery of a peptide selective for collagen III and a strategy to develop an imaging probe with superior properties for in vivo molecular magnetic resonance imaging (MRI) applications.
A small peptide was screened and selected from a library of peptides with potential to bind to collagen identified based on protein-protein interaction studies. The peptide was conjugated to a DOTA-chelator and labelled with Europium [Eu(III)] for in vitro binding assays; gallium (68Ga) for in vivo PET/CT biodistribution; and gadolinium [Gd(III)] for in vivo MRI studies. The probe was further modified to increase the number of Gd(III) per peptide (from one to four) to amplify and prolong the MRI signal. The probe was validated using a surgical mouse model of myocardial infarction (MI). In vivo MRI was performed at days 10 and 21 post-MI (n=7). Imaging findings were validated with tissue analysis. A negative control probe, carrying a scrambled peptide sequence was used. All MRI experiments were performed at a 3 Tesla clinical MRI scanner.
In vitro binding assays showed that the probe has a good affinity towards collagen III (Kd= 5.2±1.3μM) that is in the ideal range for a molecular imaging probe.4 Lack of binding of the scrambled probe (negative control) proved the specificity our probe (figure 1A). In vivo PET/CT biodistribution showed favourable pharmacokinetics with fast blood clearance and no unspecific binding (figure 1B). In vivo cardiac MRI showed selective late gadolinium enhancement (LGE) of the fibrotic scar at day 10 which decreased by day 21. This observation is expected as collagen III naturally gets replaced by collagen I at the later stages of cardiac fibrosis. The imaging data are validated histologically showing co-localisation of the MRI signal with collagen III (green colour) at day 10 and reduction of collagen III at day 21 (figure 2). Importantly, no enhancement was observed using the negative control probe and a clinically approved non-collagen targeting probe (Gadovist).
We have developed a new molecular imaging probe specific for collagen type III. Using this probe, we have successfully imaged - previously undetectable - collagen III in cardiac fibrosis. This approach may enable early detection and characterisation of cardiac fibrosis in vivo allowing staging of disease and monitoring of therapie
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