1,720,955 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
Antiproteasic activity of C1 inhibitor. Therapeutic perspectives
No full textKallikrein is a protease involved in the inflammatory process causing acute pancreatitis. Attempts to prevent this process with antiprotease agents have been successful in experimental animal models but disappointing in humans. We studied 40 consecutive patients undergoing endoscopic papillosphincterotomy. This procedure can induce a transient, moderate pancreatic inflammatory reaction, characterized by hyperamylasemia, which in 1-6% of the patients may evolve to acute pancreatitis. To assess the capacity of C1 inhibitor, the main physiological inhibitor of kallikrein, to prevent such complications, we pretreated 20 patients with 3000 U of C1 inhibitor plasma concentrate i.v.; 20 patients served as controls. Serum levels of amylase and functional C1 inhibitor were determined before the procedure and after 2, 4, 8 and 24 hours. Serum levels of amylase in the control group (146 +/- 21 IU) and in the group treated with C1 inhibitor (158 +/- 25 IU) were similar before treatment. Four and 8 hours after the end of the procedure, amylase levels were significantly lower (p < 0.001) in the treated group (231 +/- 46 and 355 +/- 104 IU) than in the control subjects (969 +/- 229 and 923 +/- 207 IU). After 24 hours both groups had normal amylase levels. In treated patients, functional levels of C1 inhibitor increased from 104 +/- 30 to 175 +/- 30% and remained elevated throughout the observation period. These data indicate that C1 inhibitor plasma concentrate can prevent hyperamylasemia following pancreas injury, probably, by inhibiting the kallikrein-mediated inflammatory process. C1 inhibitor might benefit patients at high risk of pancreatitis who undergo endoscopic papillosphincterotom
Posttransfusion anaphylactic reactions in a patient with severe von Willebrand disease : role of complement and alloantibodies to von Willebrand factor
No full textPrevious studies have suggested that activation of the complement system might be a major mechanism for posttransfusion non-immunoglobulin (Ig) E-mediated anaphylactic reactions, but its causative effect has not been clearly demonstrated in human models. Serial plasma samples were collected from a patient with severe von Willebrand disease, IgG alloantibodies against von Willebrand factor (vWF), and a history of posttransfusion anaphylaxis. During an 18-day period the patient was treated with factor VIII-vWF concentrate and with recombinant factor VIII. Complement system activation was assessed from plasma levels of C4a, C3a, cleavage products of complement factor B, soluble terminal complement complex, C1 inhibitor and C4-binding protein, and the contact phase of coagulation was assessed from plasma levels of activated factor XII and cleaved high-molecular-weight kininogen. Plasma levels of antibodies to vWF and complement-fixing IgG-vWF complexes were also evaluated. Symptoms of anaphylaxis and signs of complement activation were present only when IgG antibodies to vWF were measurable during replacement with factor VIII-vWF concentrate (days 1 and 6). IgE, IgA, and IgM antibodies to vWF were not detectable in plasma at any time. Replacement with recombinant factor VIII (days 7 to 18) secured hemostasis and did not elicit anaphylactic reactions, and complement parameters did not significantly change even when antibodies to vWF reached peak plasma levels. This prospective study of a natural clinical model indicates a cause-effect relationship between formation of IgG-vWF complexes and massive complement activation in posttransfusion non-IgE-mediated anaphylactic reactions
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
Infusion of C1-inhibitor plasma concentrate prevents hyperamylasemia induced by endoscopic sphincterotomy
No full textHyperamylasemia after endoscopic sphincterotomy is a common event, occurring in about 70% of cases. Clinical acute pancreatitis may also develop in 1% to 6% of cases. Previous attempts to prevent this reaction with inhibitors of exocrine pancreatic secretion (somatostatin and octreotide) provided conflicting and often disappointing results. Kallikrein is one of the proteases that sustain the inflammatory process in acute pancreatitis; the C1 inhibitor is the only physiologic inhibitor of the first component of the human complement cascade and is a major inactivator of kallikrein and Factor XII. Therefore, we tested the C1 inhibitor in the prevention of hyperamylasemia in 40 consecutive patients undergoing endoscopic sphincterotomy for common bile duct stones or benign papillary stenosis. They were given either C1 inhibitor (20 cases) or placebo (20 cases) before the procedure. Serum amylase levels were determined at baseline and 2, 4, 8, and 24 hours thereafter. Significant differences in serum amylase levels between groups were observed at 2 hours (p < .01), 4 hours (p < .0005), and 8 hours (p < .005) after sphincterotomy. The differences in amylase levels were also significant among the 24 subjects with pancreatic ductal filling (2 hours, p < .05; 4 hours, p < .005; 8 hours, p < .01) and the 9 patients with previous episodes of acute pancreatitis (4 hours, p < .05; 8 hours, p < .05; 24 hours, p < .05). The infusion of C1-inhibitor plasma concentrate resulted in a 50% increase in functional levels of C1 inhibitor (in the 8 cases for whom they were assayed), which persisted throughout the observation period
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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