1,721,041 research outputs found
Prevalence of Bartonella henselae in Italian Stray Cats: Evaluation of Serology To Assess the Risk of Transmission of Bartonella to Humans
Full text linkBartonella henselae is the major etiological agent of cat scratch disease in humans. Cats act as the natural reservoir of B. henselae and can transmit the infection to humans by a bite or scratch. The prevalence of B. henselae in cat populations was evaluated by serological and bacteriological tests. A total of 769 stray cats from three urban and three rural areas in northern Italy were sampled between January 1999 and December 2000. The positive and the negative predictive values of serological tests with respect to bacteremic status were evaluated. Tests of a total of 140 cats (18%) resulted in detection of bacteremia. A total of 540 cats were tested by serology; 207 (38%) were seropositive. Of the 531 cats tested by both methods, the results for 65 (12.2%) showed both bacteremia detection and seropositivity. The molecular typing of the isolates showed that 20.6% of bacteremic cats were infected with B. henselae type I strain, 61.1% were infected with B. henselae type II, and 18.3% were coinfected with both. A statistically significant difference in antibody and bacteremia prevalences among geographical areas was detected. Statistical analysis showed no association between characteristics such as seroprevalence-bacteremic status, sex, general health status, and the presence of ectoparasites. The negative predictive value of serological test was 84.7%, and the positive predictive value was 31.8%. Receiving operator characteristic analysis of the data showed that serological tests had a low predictive value in relation to the bacteremic status of a cat; in surveys aimed at assessing the real risk of B. henselae infection in a human population, therefore, we suggest the use of blood culture as the reference test. Nevertheless, both blood culture assays and serological tests for Bartonella infection should be performed for a complete evaluation of the health status of cats
Comparison between specific immunoperoxidase staining and bacteriological culture in the diagnosis of renal leptospirosis of pigs
No full textSeventy-two pigs were examined for the presence of leptospires in the kidney by both bacteriological culture and an immunoperoxidase procedure performed on formalin-fixed, paraffin-embedded sections of tissue with a primary antibody raised in rabbits against serovar pomona. The methods were in accordance in 62 of 70 (89 per cent) of the specimens. Compared with culture the sensitivity of the immunoperoxidase procedure was 30 of 38 (78 per cent) and its specificity 100 per cent; the predictive value of a positive result was 100 per cent, of a negative result, 80 per cent. The major advantages of the immunoperoxidase procedure are specificity, speed of execution and the possibility of simultaneous visualisation of leptospiral antigen and microscopic lesion
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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