1,720,999 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
In vitro gallbladder motility in patients with radiolucent and radiopaque stones.
No full textTwenty-five gallbladders were studied in vitro. Sixteen had radiolucent gallstones and 9 had radiopaque gallstones. The radiolucent gallstones had a cholesterol content of 94.17 +/- 3.76% and the radiopaque gallstones had a cholesterol content of 56.6 +/- 4.46%. Half the maximal response (ED50) to cholecystokinin octapeptide (CCK-OP) and to carbachol in strips from patients with radiolucent gallstones was 0.8 +/- 0.15 and 27.01 +/- 3.74 x 10(-7) M, respectively. In strips from patients with radiopaque gallstones, the ED50 was 0.4 +/- 0.08 and 14.92 +/- 3.07 x 10(-7) M, respectively. The ED50 values to CCK-OP and carbachol were greater in strips from specimens with radiolucent gallstones than in strips from specimens with radiopaque gallstones (p less than 0.05). There was no significant difference in the maximal contractile response of the two groups. It can be concluded that gallbladder sensitivity to CCK-OP and carbachol can be modified in relation to differences in the cholesterol and calcium content of the stones
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
Gender- and age-related differences in muscular and nerve-mediated responses in human colon
No full textBackground: Gender- and age-related differences in muscular and nerve-mediated responses in human colon are poorly characterized. We studied carbachol-induced motor responses and electrically evoked contractions in sigmoid circular muscle from adult and elderly patients of different gender. Methods: Sigmoid colon segments were obtained from 24 men and 16 women undergoing left hemicolectomy for colon cancer. Isometric tension was measured on muscle strips exposed to increasing carbachol concentrations. The effects of atropine, guanethidine, l-nitro arginine methyl ester (l-NAME), and tetrodotoxin on electrically evoked contractions were also studied. Results: Female patients showed higher maximal response to carbachol than male patients, elderly females being the most sensitive to carbachol among all patient groups. Electrically evoked contractions were linearly related to stimulation frequency and abolished by tetrodotoxin. Electrically evoked contractions were significantly more pronounced in elderly male patients; they were reduced by atropine and guanethidine and increased by l-nitro arginine methyl ester in the presence of atropine and guanethidine (P < 0.05). The effect of l-NAME was most marked in elderly male patients and least pronounced in elderly females. Conclusions: The response to carbachol and the role of nitrergic pathways differ according to age and gender; this may depend on muscarinic receptor upregulation or humoral factors affecting nitric oxide release, respectively
Sex steroid hormone receptors and human gallbladder motility in vitro.
No full textThis study was designed to investigate the relationship between estrogen and progesterone receptor levels and in vitro contractile response of gallbladder muscle strips to stimulation by carbachol and cholecystokinin-octapeptide (CCK-OP). Seventeen female postmenopausal patients cholecystectomized for gallstones were studied. Samples of the gallbladder wall were used for histological examination; motility was studied by Keane et al. [Surg Gynecol Obstet 1986; 163:555-560]; the estrogen and progesterone receptor levels were evaluated by immunoenzymatic assay. Positive correlations were found between the progesterone receptor level and the carbachol concentration that produced half the maximal response (ED50), and between the estrogen receptor level and the ED50 of CCK-OP. Our data confirm the presence of estrogen and progesterone receptors in the gallbladder and suggest that sex steroid hormones act on gallbladder motility by modulating the affinity of gallbladder receptors to CCK-OP and carbachol
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