1,720,957 research outputs found
Sex steroid hormones influence the cAMP content in human endometrium during the menstrual cycle.
No full textThe measurement of the tissue concentrations of cyclic adenosine monophosphate (cAMP) in human endometrium shows that the levels of the nucleotide vary during the menstrual cycle, being 11.4 +/- (SE) 2.5 and 37.7 +/- (SE) 10.1 pmol/mg protein in the proliferative and secretory phase, respectively. The individual determinations of cAMP are significantly correlated to the estradiol/progesterone blood concentration ratio: by this means we obtained a superimposable distribution with the results of histologic examination suggesting that the hormones have a direct action in determining the cAMP levels in this tissue. The relevance of these observations for the physiology of the endometrium is discussed
Short-term effect of oophorectomy on lipoprotein metabolism.
No full textThe influence of steroid hormones on lipoprotein metabolism has been investigated in menstruating women undergoing oophorectomy; indeed, by this procedure, it is possible to alter selectively the secretion of the hormones and thus to determine the influence of their withdrawal on blood lipids. Within 3 months of surgery we observed significant rapid changes in cholesterol levels of total and HDL-bound components (early decrease and subsequent increase) without alteration of the triglyceride component of the lipoproteins. Similar biphasic changes were observed for the apolipoproteins A and B, determined by immunological methods. These results are suggestive of an action of sex hormones on the lipoprotein metabolism, both on the lipid and the protein moieties. They can be explained by a primary action of the hormones on the apolipoprotein metabolism and a secondary apoprotein-mediated effect on the lipid component of the lipoproteins
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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