1,721,169 research outputs found
Agatocle di Siracusa : un tiranno operaio
No full textLa propaganda populistica di Agatocle di Siracusa in Diodoro Siculo
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
Antibacterial activity of yoghurt against viridans streptococci in vitro
No full textObjective: Yoghurt consumption leads to a selective decrease in the oral level of mutans streptococci. It is not clear whether this decrease is due to the bactericidal activity of yoghurt or other mechanisms. The present study investigated the differences in susceptibility to yoghurt between several strains of viridans streptococci. Design: The sources of variation were minimised, at the expense of the external validity of the study, using culture collection strains. Each strain was tested separately on five occasions in planktonic form and logarithmic growth phase. Two strains of each of the following Streptococcus species were tested: mutans, sobrinus, gordonii, oralis, parasanguinis and sanguinis. One millilitre [108 colony-forming units (cfu)] of each strain was incubated (37 °C, 60 min) with 9 mL of fat-free plain yoghurt containing Streptococcus thermophilus and Lactobacillus bulgaricus (108 and 107 cfu/g, respectively) in gently vortexed tubes. Survival rates were calculated every 15 min by dividing the number of viable cells, obtained using conventional laboratory procedures, by the baseline number. Results: Survival rates were 8% (S. mutans 6519T), 12% (S. mutans 31738), 35% (S. oralis 25671) and >50% (all other species tested) after 15 min, and 0.01% (S. mutans) and >10% (all other species tested) after 30 min. Overall, S. parasanguinis and S. sobrinus were the most resistant species. When heat-treated yoghurt (<10 cfu/g bacteria and inactivated bacteriocins) was used, this antibacterial activity was not found. Conclusion: In vitro, yoghurt with live bacteria showed selective anti-mutans activity, suggesting that the overall decrease in mutans streptococci in vivo could be due to a bactericidal effect on S. mutans but not on S. sobrinus. © 2008 Elsevier Ltd. All rights reserved
Effect of orthodontic therapy with fixed and removable appliances on oral microbiota: a six-month longitudinal study.
No full textThe present study evaluated microbiological and clinical changes occurring during the first six months of orthodontic therapy with fixed and removable appliances and the consequent risk for gingivitis and periodontal disease. This study was justified by the disagreement among different authors: only some of them reported gingivitis development and changes in dental plaque composition during orthodontic therapy with fixed appliances, others did not. Thirty, 7-to-15-year-old children, fifteen with fixed and fifteen with removable appliances, previously motivated to oral hygiene, completed the study. They were clinically examined by a dentist at baseline and at the end of the study. Three supra and subgingival microflora samples were collected from the first molars, when the appliances were inserted (T0), 6-8 weeks later (T1) and 6-7 months later (T2). Microflora was examined using dark-field and light microscopes and cultural methods. An indicator of healthy status (percentage of Gram positive cocci in total bacterial count) and some risk indicators for gingivitis (bacterial count evaluated with light microscope, percentage of Gram negative rods) and for periodontitis (motile rod and spirochete percentages, presumptive Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis prevalence) were investigated. Patients with fixed appliances were clinically healthy at T2; yet they showed significantly increased counts, motile rods, subgingival spirochetes and a decrease of Gram positive cocci. At T2, patients with removable appliances were clinically healthy and the only significant microbiological changes were supragingival motile rods and subgingival spirochetes. These data suggest that in the oral hygiene motivated patients of the present study, gingivitis and periodontitis do not occur, during the first six months of treatment: the significant modification of oral microbiota, shown by subjects with fixed appliances, however, suggests that the risk for gingivitis in the following months of therapy is still high and the risk for periodontitis cannot be excluded
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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