1,721,094 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
Microdialysis as a tool to assess interstitial norepinephrine levels in adipose tissue of spontaneously hypertensive rats.
No full textThe microdialysis technique was applied to the study of norepinephrine (NE) metabolism in white adipose tissue of spontaneously hypertensive (SHR, n = 6) and normotensive Wistar-Kyoto (WKY, n = 6) rats. Mean concentrations of interstitial NE were much higher in SHR as compared to WKY (mean +/- SEM: 980.9 +/- 125.6 pg/ml vs 520.7 +/- 96.1 pg/ml; p = 0.01) over the 180 min experimental period. These results are consistent with the hypothesis that sustained outflow from nerve endings of the peripheral sympathetic system may play a role in the maintenance of arterial hypertension. Owing to its low invasiveness, the microdialysis technique allows to continuously monitor NE extracellular levels in conscious and freely-moving animals
Sul meccanismo dell'effetto antipertensivo del furosemide
No full textAbstract
Diuretics are antihypertensive drugs, because they lower the arterial pressure of hypertensive patients and have no effect on that of normal subjects. It is supposed that their antihypertensive effect is due to volume depletion; however, it could be more complex. In 17 patients with essential hypertension we have evaluated the arterial pressure before and during the administration of furosemide (1 mg/kg/day for 5 days), then after having restored the sodium and volume balance by the administration of saline solution (2,8 mEq/kg/day of Na for 5 days). In 4 patients we have measured the cardiac output (CO) and calculated the peripheral resistance (PR) before and after the 10 days of treatment. The mean arterial pressure decreased after the administration of furosemide (from 138,6 ± 15,5 to 116,0 ± 10,5 mmHg) and was still low after the sodium balance was restored to the initial value (120,2 ± 12,7 mmHg p < 0,001). In the cases where the haemodynamic changes were investigated, a 11,4% fall of mean arterial pressure (from 162,2 to 143,7 p < 0,01) was due in minor part to a decrease in CO (-3,0% n.s.) and more to a fall of PR (mean = -9,9% p< 0,05) while the plasma volume was unaltered (mean = + 1,5% n.s.). These data demonstrate that diuretics promote a haemodynamic rearrangement that is still present when saltvolume depletion is reequilibrated
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