1,720,966 research outputs found
Which ratio should be adopted to evaluate the urinary excretion of testosterone and epitestosterone in veal calves?
No full text- Control of the illicit use of endogenous hormones in meat producing animals requires a detailed knowledge of both the metabolism of endogenous hormones and their physiological profiles in each species. Nowadays current approaches in cattle do not involve the determination of the absolute urinary concentration of endogenous hormones because no validated physiological levels are recognised; the same is true when the ratio between metabolites is considered, as applied for testosterone (T) and epitestosterone (E) in athletes (1). In man, urinary epitestosterone has attracted the attention as a reference substance in the doping control of testosterone abuse. The nearly constant urinary ratio of T to E (T/E) in adults became the basis of the method of detection of exogenously administered testosterone, since in humans epitestosterone does not originate from exogenous testosterone in significant amounts (2). Data from literature (2,3,4) reported that in cattle epitestosterone is a metabolite of testosterone probably produced in liver and blood by hydroxysteroid-oxido-reductase enzymes via androstenedione. Aim of the study was a preliminary approach to assess physiological concentrations of T and E in urine of veal calves, and to evaluate which urinary ratio could be useful to indicate hormone treatments in calves.
- The results reported showed that, despite the large variations of T and E concentrations in urine collected from veal calves, the physiological excretion of E was about ten times greater than T, and E excretion tends to decrease with increased age, as reported in young and adult men (2). Since in men urine concentrations of E and T are quite similar, and the excretion of E remained rather constant when exogenous T was administered; a cut-off value for T/E in urine was established for doping control (5). In a previous paper we applied the T/E ratio approach to urine of veal calves, but the influence of treatment was masked and no significant difference were observed between treated and control calves (6). Now, our recent data, confirmed that repeated treatments with natural hormone could cause a time-course reduction of urinary E as already reported (3, 7); applying the E/T ratio, the reduction of E urinary excretion was confirmed in Testosterone treated (A) but not in Boldenone treated calves (B and C)
The urinary ratio of testosterone to epitetosterone: A good marker of illegal treatment also in cattle?
No full textThe authors evaluated the suitability of the testosterone: epitestosterone ratio, in calf urine, as a tool to detect the abuse of hormone treatments in food production species
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
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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