1,721,006 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
Ultra-low-dose chest CT in adult patients with cystic fibrosis using a third-generation dual-source CT scanner
No full textIntroduction: Chest computed tomography (CT) examinations are performed routinely in some cystic fibrosis (CF) centers in order to evaluate lung disease progression in CF patients. Continuous CT technological advancement in theory could allows a lower radiation exposure of CF patients during chest CT examinations without an image quality reduction, and this could become increasingly important over time in order to reduce the cumulative radiation dose effects given the continuous increase of CF patients predicted median survival. Objective: The aim of this study was to compare objective and subjective image quality and radiation dose between low-dose chest CT examinations performed in adult CF patients using a third-generation DSCT scanner and a 64-slices single-source CT (SSCT) scanner. Materials and methods: Between January 2016 and August 2019, 81 CF patients underwent low-dose chest CT examinations using both a 64-slices SSCT scanner (2016–2017) and a third-generation DSCT scanner (2018–2019). Objective image noise standard deviation (INSD), signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), overall subjective image quality (OSIQ), subjective image noise (SIN), subjective evaluation of streaking artifacts (SA), movement artifacts (MA) and edge resolution (ER), dose-length product (DLP), volume computed tomography dose index (CTDIvol) and effective radiation dose (ERD) were compared between DSCT and SSCT examinations. DSCT examinations consisted in spiral inspiratory end expiratory acquisitions. SSCT examinations consisted in spiral inspiratory acquisitions and five axial expiratory ones. Results: DSCT protocol showed statistically significant lower spiral inspiratory phase mean DLP, CTDIvol and ERD than SSCT protocol, with a 25% DLP, CTDIvol and ERD reduction. DSCT protocol showed statistically significant higher overall (inspiratory and expiratory phases) mean DLP, CTDIvol and ERD than SSCT protocol, with a 40% DLP, CTDIvol and ERD increase. Objective image quality (INSD, SNR and CNR) and SIN differences were not statistically significant, but subjective evaluation of DSCT images showed statistically significant better OSIQ and ER, as well as statistically significant lower SA and MA with respect to SSCT images. Conclusions: To our knowledge, this is the first study evaluating chest CT image quality and radiation dose in adult CF patients using a third-generation DSCT scanner, and it showed that technological advancements could be used in order to reduce radiation exposure of volumetric examinations. The spiral inspiratory dose reduction can be obtained with concomitant improvements in subjective image quality with comparable objective quality. This will probably allow a wider use of this imaging modality in order to assess bronchiectasis and will probably foster spiral expiratory acquisition for small airways disease evaluation
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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