1,720,970 research outputs found
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
Effect of moderate exercise on Crohn's disease patients in remission.
No full textBackground. Physical exercise may exacerbate the disturbed homeostasis of Crohn's disease patients. Aim. To examine the effect of moderate physical exercise on gastrointestinal function in a group of Crohn's disease patients in remission.
Patients and Methods, The effect of one-hour's exercise at a maximum of 60% oxygen consumption was evaluated in six males with ileal Crohn's disease in remission on orocaecal transit time (breath rest to lactulose), intestinal permeability (6-hours' urinary excretion of a sugar mixture of lactulose/mannitol), polymorphonuclear leucocytes function (peripheral blood chemiluminescence), lipoperoxidation (plasma malondialdehyde) and antioxidant trace elements (urinary and plasma zinc and copper concentrations). Six healthy age-matched subjects sewed as controls.
Results. Exercise did nos elicit subjective symptoms or changes in intestinal permeability and lipoperoxidation. orocaecal transit time increased after exercise in Crohn's disease patients (72 min+/-30 vs 100 min+/-34) with no significant difference from controls (77 min+/-20 vs 83 min+/-23). Neutrophils, primed pre-exercise in Crohn's disease patients showed an increased post-exercise chemiluminescence similar to controls. Zinc urinary output significantly increased after exercise in Crohn's disease patients and remained unchanged in control subjects.
Conclusions. Moderate aerobic exercise has no significant effect on the gastrointestinal parameters examined. However; basal neutrophil activation and exercise in Crohn's disease patients may trigger an excessive production of oxygen metabolites. Moreover; exercise may contribute to an increased risk of zinc deficiency
Zinc therapy increases doudenal concentrations of metallothionein and iron in Wilson's disease patients
No full textObjective: Wilson's disease is effectively treated by zinc administration which, in vitro, increases metallothionein concentrations. To ascertain whether the latter also occurs in humans we measured metallothionein and trace element concentrations in the duodenal mucosa of 15 Wilson's disease patients: 12 treated with zinc sulphate, two treated with penicillamine, and one not yet on treatment. The control group consisted of 17 patients with dyspepsia, who underwent the same study protocol. Methods: Metallothionein and trace element concentrations were measured in duodenal mucosa biopsies according to the silver-saturation hemolysate method and atomic absorption spectrophotometry. Results: Metallothionein concentrations increased by 1500% after zinc and 150% after penicillamine in Wilson's disease patients, with respect to controls who had negative endoscopy and Wilson's disease patients who were not treated. A significant correlation was found between metallothionein and duodenal zinc concentrations. Mucosal iron concentration increased in Wilson's disease patients whether they were treated with zinc or penicillamine, Duodenum with duodenitis also had significantly increased iron levels compared with normal duodenum, Conclusions: Zinc administration increases intestinal metallothionein in Wilson's disease patients. The blockade of copper absorption and its elimination in the stools on desquamation of the intestinal cells probably explains one of the mechanisms underlying the effect of zinc treatment, Despite normal endoscopy, Wilson's disease patients present increased mucosal iron concentrations similar to those in controls with duodenitis. Metallothionein may therefore prevent oxidative damage caused by metal toxicit
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