1,720,958 research outputs found

    The aetiology of chronic hepatitis in Italy: results from a multicentre national study

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    Background: No recent national-level data on the aetiology of chronic hepatitis are available in Italy. Aim: To evaluate the current aetiology of chronic hepatitis in Italy. Patients: A total of 6210 chronic hepatitis patients (both prevalence and incident cases) consecutively admitted to 79 hospitals located throughout Italy were enrolled over a 6-month period in 2001. The hospitals were randomly selected through systematic cluster sampling. Results: The main agent associated with chronic hepatitis was hepatitis C virus, which was found in 76.5% of the patients (in 62.6% it was the only aetiologic factor). Hepatitis B surface antigen was present in the serum of 12.2% of the cases (in 9.2% it was the only aetiologic factor). Hepatitis B e antigen and hepatitis Delta were detected in 16.6% and 7.0%, respectively, of hepatitis B surface antigen-positive patients. A history of alcohol abuse was found in 19.2% of the cases (5.5% without viral infection). Autoimmune hepatitis and inborn metabolic disorders were extremely rare. The prevalence of hepatitis C virus-related cases was significantly lower in incident cases, compared to prevalent cases (55.1% versus 65.0%; p < 0.01). The mean alanine aminotransferase level was significantly higher in hepatitis B surface antigen-positive patients, compared to hepatitis B surface antigen-negative patients. The histology was less severe in non-viral-related cases. Conclusions: Hepatitis C virus is the most important pathogenic factor for chronic hepatitis in Italy; however, the comparison between prevalent and incident cases suggests that this infection will play a less important role in the future. A comparison with previous reports shows that both hepatitis B virus-related and hepatitis Delta virus-related cases are decreasing

    The importance of HCV on the burden of chronic liver disease in Italy: a multicenter prevalence study of 9,997 cases

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    Knowledge of the current epidemiology of chronic liver disease in Italy is mostly obsolete and fragmentary for the lack of up-to-date consistent data. In 2001, a 6-month prevalence study was undertaken in 79 hospitals to assess the characteristics of chronic liver disease in Italy. Both prevalent and incident cases were enrolled. A total of 9,997 patients were recruited, of whom 939 (9.4%) had normal liver biochemistry, 6,210 (62.1%) had chronic hepatitis, 1,940 (19.4%) had liver cirrhosis, and 341 (3.4%) had hepatocellular carcinoma (HCC). In 567 patients (5.7%) the diagnosis was not established. Hepatitis C virus (HCV) was found in 69.9% of the patients and was the only etiological factor in 56.3% of all the patients. Hepatitis B surface antigen (HBsAg) was present in the serum of 13.4% of the cases (in 10% it was the only etiological factor). A history of alcohol abuse was found in 23% of the cases (9.4% without viral infection). The prevalence of HCV-related cases was significantly lower in incident than in prevalent cases (44.9% vs. 59.9%, P<0.0001), while the proportion of patients with alcohol abuse was much higher in incident than in prevalent cases (18.1% vs. 6.6%, P<0.0001). These findings indicate that nearly one quarter of patients with chronic liver diseases in Italy have a severe disease such as liver cirrhosis and HCC represents a not negligible burden for the national health system. Hepatitis B fell in importance as an etiological factor. Hepatitis C is the important pathogenic factor for chronic liver disease in Italy. However, a comparison between the prevalent and incident cases suggests that in future HCV infection will also play a progressively decreasing role, in part as a consequence of treatment

    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The 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

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    “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

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    We 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

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    We 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

    Author Index

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