1,720,998 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
Magnetic resonance urography vs computed tomography urography in the evaluation of patients with haematuria
No full textPURPOSE:
This study was done to evaluate by direct comparison the image quality of magnetic resonance urography (MRU) and computed tomography urography (CTU) and to assess the diagnostic confidence of the two techniques in detecting urothelial malignancy in patients with haematuria MATERIALS AND METHODS: Thirty-five patients with haematuria underwent both CTU and MRU. Two different investigators evaluated calyceal, renal pelvis, ureteral and bladder visibility. Their diagnostic confidence in detecting urothelial malignancy with the two procedures was assessed. A Wilcoxon matched-pairs test was performed to compare results. Inter-reader agreement was calculated by weighted kappa (WK) statistic. Patient history (further examinations, cystoscopy and histological specimens) was considered as reference standard to calculate receiver operating characteristic (ROC) curves of diagnostic confidence.
RESULTS:
CTU provided better visibility of urothelial structures (p<0.01) and allowed for greater diagnostic confidence (ROC area 0.994 vs. 0.938) than MRU, with a good inter-reader agreement (WK=0.62). Nevertheless, in obstructive patients with impaired excretory function, MRU, thanks to the static-fluid technique, offered better visualisation than CTU.
CONCLUSIONS:
There is a potential role for MRU in urinary tract imaging, but as diagnostic confidence in detecting urothelial malignancy is poorer than in CTU, it might be stareserved for patients at low risk for malignancy and for evaluating obstructed patients
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
Imaging of Non-vascular Thoracic Pain
No full textAcute chest pain is one of the most frequent requests for seeking medical attention in the emergency department. For patients suffering from chest pain, ruling out cardiovascular diseases is mandatory. Nevertheless, chest pain of noncardiac origin is frequent and includes a large variety of clinical conditions, such as parenchymal, pleural, musculoskeletal, oesophageal, psychogenic or neurologic diseases. Various imaging modalities, along with clinical and hematologic evaluation, are needed to evaluate and characterize such heterogeneous group of pathologies. Chest radiography (CXR) is almost always the first imaging technique used to define the underlying disease (i.e. parenchymal, pleural, musculoskeletal). Nevertheless, given its non-specific findings, further imaging techniques are frequently requested. A pivotal role is played by computed tomography (CT), the latter capable of determining location, nature and extent of various diseases. Ultrasonography (US), magnetic resonance imaging (MRI) and positron emission tomography (PET) play a secondary role for the evaluation of acute chest pain, being most frequently used in specific settings.
In this chapter, the authors review the most common conditions causing non-cardiovascular chest pain, highlighting the main imaging pearls and pitfalls, as well as the most relevant differential diagnoses
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