1,721,231 research outputs found
The prevalence of bright liver echo pattern in patients with chronic hepatitis C: correlation with steatosis and fibrosis
No full textPurpose: To evaluate the prevalence of bright liver echo pattern (BLP) on ultrasonography and its correlation with liver steatosis (LS), and fibrosis in patients with chronic hepatitis C. The usefulness of detecting skip areas for steatosis diagnosis has also been evaluated. Methods: The study included 88 patients with chronic hepatitis C (55 men, 33 women, average age 45.7 ± 11.2 years). Ultrasound examination was performed in all patients before liver biopsy. The presence of BLP was assessed and graded from 1 to 3. Hypoechogenic areas (skip areas) around the gallbladder or near the portal vein were also evaluated. Hepatic fibrosis was assessed using the Ishak fibrosis score. Steatosis was graded as follows: 1, 2, 3 (<30, 30–70, >70 % of hepatocytes affected, respectively). Results: Fifty-three of the 88 patients (60 %) showed BLP (40 grade 1, 13 grades 2 or 3). Skip areas were found in 14 patients (16 %). Histological steatosis was observed in 40 patients (45 %) and in 10 of them (25 %) was grades 2 and 3 (4 and 6 patients, respectively). As regards fibrosis, 2 patients showed F0, 34 F1, 28 F2, 20 F3, 4 F4, none of them F5 and F6. BLP of grades 2 or 3 and presence of skip areas were strongly correlated with LS (P = 0.00007 and P = 0.00003, respectively). No correlation was found between BLP and fibrosis. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of BLP for LS were 75, 50, 56, 68 and 61 %, respectively. When BLP of grades 2 and 3 and LS of 30 % or more were correlated, the sensitivity, specificity, PPV, NPV and accuracy of BLP were 72, 96, 61, 96 and 90 %, respectively. As regards skip areas the sensitivity, specificity, PPV, NPV and accuracy for LS were 35, 100, 100, 64 and 70 %, respectively. Conclusions: In a well-defined group of patients with chronic hepatitis C, the detection of BLP grades 2 and 3 has a good sensitivity and high specificity for high grades of steatosis. A high specificity but low sensitivity for liver steatosis was also found for skip areas, whereas mild fibrosis does not seem to correlate with the hyperechogenicity of the live
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Idiopathic interstitial pneumonias. Primum movens: epithelial, endothelial or whatever?
No full textThe pathogenesis of idiopathic interstitial pneumonias (IIPs), particularly of idiopathic pulmonary fibrosis (IPF), is still unknown and the precise nature of the primum movens is strongly debated. Epithelial cells can be the first target of various environmental toxic agents. Both types of pneumocytes may be injured. Type I pneumocyte loss, however, is most conspicuous in fibroblastic foci, the principal sites where irreversible fibrogenesis starts. Epithelial regeneration is highly disturbed: cuboidal and bronchial cells are mainly involved in alveolar repair. These cells, unable to accomplish important functions of normal pneumocytes, secrete various factors inducing migration and proliferation of fibroblasts responsible for progressive extracellular matrix accumulation and lung remodelling. Endothelial cells may also be considered the major players in the initiation of fibrogenic events. Microvascular injury has been largely demonstrated as an early event in IPF lungs. Thrombin as well as other coagulation products has many biological effects such as the activation of different profibrotic factors, which in addition to other fibrogenetic molecules released by stimulated endothelium, are responsible for migration and proliferation of fibroblasts. The old pathogenesis of IPF: chronic inflammation can now be considered the principal event in other non IPF-IIPs. Among inflammatory cells, different cell types have been extensively suggested to play a key role in the pathogenesis of pulmonary fibrosis: granulocytes and eosinophils or mast cells. More recently novel mechanisms underlying the pathogenesis of pulmonary fibrosis have been proposed: bone marrow-derived stem cells may play a crucial role in the fibroproliferative response as well as in epithelial regeneration
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