1,721,118 research outputs found
A serologic survey of Helicobacter pylori infection in 3281 Italian patients endoscoped for upper gastrointestinal symptoms
No full textAim: To assess the seroprevalence of Helicobacter pylori infection in a large series of patients with upper gastrointestinal symptoms referred for their first upper gastrointestinal endoscopy, and to evaluate any association with disease. Methods: A large survey of 3281 dyspeptic patients undergoing their first endoscopic examination was undertaken, involving 93 centres in Italy. A blood sample was taken from each participant, for measuring IgG antibodies against H. pylori using a commercially available kit, and two biopsies of the antral gastric mucosa were obtained for evaluating a Giemsa-stained specimen. Results: Endoscopic macroscopic diagnoses included normal mucosa (25.3%), gastroduodenitis (51.6%), gastric and duodenal ulcers (3.7 and 14.9%, respectively) and other conditions, including gastric cancer (0.8%). Overall, the seroprevalence result was 71.3% with a strong positive association with increasing age and male sex and a negative one with educational level. According to endoscopic diagnoses, the association with H. pylori seropositivity was highest for duodenal and gastric ulcer (multivariate odds ratio: 6.1 and 2.2) and lowest for carcinoma. The comparison between the results of serology and the single Giemsa-stained specimen showed good reliability of H. pylori IgG, particularly in a subgroup (n = 2056) for which the interpretation was performed by a single dedicated pathologist: sensitivity and specificity were 92 and 78%, respectively. Conclusion: Commercial IgG serology is a reliable tool for the assessment of H. pylori infection in large-scale multicentre surveys. A very high seroprevalence among dyspeptic patients was confirmed, particularly in the presence of peptic disease. Factors associated with the infection were very similar to those usually reported in the general population, but male patients showed a significantly higher prevalence
A serologic survey of Helicobacter pylori infection in 3281 Italian patients endoscoped for upper gastrointestinal symptomps
No full textShort stature and Helicobacter pylori in Italian children: prospective multicenter hospital-based case-control study
No full textShort stature and Helicobacter pylori infection in Italian children: prospective multicentre hospital based case-control study.
No full text
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
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