1,720,968 research outputs found
A simple method for the measurement of human gastric emptying: standardization of operative parameters.
No full textThe radioisotopic techniques used for the measurement of gastric emptying in man require complex and expensive scintiscanners or gamma-cameras. In this investigation, a simple method utilizing a single and inexpensive detector was evaluated; in addition, the suitability of 99Tcm sulphur colloid as a label for solid meals was assessed. The procedure was found to be accurate and its reproducibility high. The calculated absorbed dose to the gut was very low. Both in vitro and in vivo studies indicate that the radiocolloid used is a food non adsorbable marker for determining gastric emptying of solids. In a group of 50 healthy volunteers the emptying half-time (t1/2) ranged between 40 and 110 min, with a mean of 71.7 +/- 10.1 min, the male subjects exhibiting a significant lower t1/2 than females. In 5 volunteers with t1/2 within the normal range, the effect of drugs acting on gastric motility was evaluated. Hyoscine N-butyl bromide (20 mg) significantly delayed gastric emptying of solids, whereas metoclopramide (20 mg) was ineffective in these subjects. On the contrary, this drug was able to accelerate gastric emptying only in some patients with abnormally delayed emptying. On the whole, the method is simple, inexpensive and reproducible. It may be of great clinical value to investigate abnormalities of gastric function and to perform a better pharmacological approach to the medical treatment
The effect of bombesin on gastric emptying of solids in man.
No full textIntravenous infusion of bombesin (5 ng.kg(-1). min(-1) significantly delayed gastric emptying of solids in man. The gastrin response to meal increased following administration of the peptide; however no correlation was found between the difference in gastrin response (to meal alone and to meal plus bombesin) and the degree of delay in emptying. In addition the behavior of intragastric pH after eating was not modified by bombesin infusion. All of these data suggest a direct effect of the peptide on gastric emptying, which was probably connected with the strong contraction of the antrum and pylorus observed in this and in previous investigations
Caerulein delays gastric emptying of solids in man.
No full textIntravenous administration of caerulein (40 ng/kg) delayed gastric emptying of solids in man. Radiological examinations demonstrated that the peptide causes a marked contraction of the pyloric sphincter and a relaxation of the gastric corpus and fundus. Therefore the effect of caerulein on gastric emptying may be considered as the result of different actions on the distal and proximal stomach. Furthermore pretreatment of the subjects with cimetidine did not modify the effect of caerulein indicating an action independent of the gastric hypersecretory effect of the peptide. The action of caerulein on gastric emptying must be kept in mind when the peptide is employed in the treatment of some pathological conditions
Inhibition of gastric emptying by bombesin in man.
No full textBombesin, administered by intravenous infusion (5 ng . kg-1 . min-1) for 60 min, significantly delayed gastric emptying of solids in man and strongly potentiated the gastrin response to food. However, no correlation was found between the difference in the integrated gastrin response (to meal and to meal plus bombesin) and the degree of delay in emptying. The effect of the peptide is most likely connected with the strong contraction of the gastroduodenal junction pinpointed in previous investigations
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
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