1,723,810 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
Enzymes and signal pathways in the pathogenesis of alcoholic cardiomyopathy
No full textOwing to its acute psychotropic effects, ethanol is the most frequently consumed toxic agent worldwide. However, excessive alcohol intake results in an array of health, social, and economic consequences, which are related to its property as an addictive substance. It has been well established that exposure to high levels of alcohol for a long period leads to the onset and progression of nonischemic cardiomyopathy through direct toxic mechanisms of ethanol and its metabolite, acetaldehyde. Excessive alcohol ingestion causes myocardial damage including disruptions of the myofibrillar architecture and is associated with reduced myocardial contractility and decreased ejection volumes. Key features of alcoholic cardiomyopathy are cardiac hypertrophy and ventricular dilatation, and the disease is manifested mainly as cardiomegaly, congestive heart failure, and even cardiac death. Mechanisms that have been postulated to underlie the pathogenesis of alcoholic cardiomyopathy include apoptosis, mitochondrial alterations, acetaldehyde protein adduct formation, oxidative stress, and imbalances in fatty acid metabolism. In the following, we give a brief overview of the molecular effects of ethanol-metabolizing enzymes and their impact on myocardial signal transduction pathways
Polymer reaction engineering, an integrated approach
No full textIn this paper we present a framework describing the developments in polymer reaction engineering (PRE), based on discussions held within the EFCE Working Party on PRE. In the past, PRE has been strongly based on engineering sciences. A changing focus, however, has induced a current integrated multidisciplinary approach that is strongly driven by sustainability. In the near future, we expect a change from ‘technology-based PRE’ towards ‘product-inspired PRE’
Tryptophan hydroxylase and 5-hydroxytryptamine in carcinoids of the gastrointestinal tract
No full textBackground: Tryptophan hydroxylase is the enzyme that catalyzes the formation of 5-hydroxy-L-tryptophan which is the initial and rate-limiting enzyme in the biosynthesis of 5-hydroxytryptamine (serotonin). The aim of this study was to analyze the differential expression of tryptophan hydroxylase and 5-hydroxytryptamine in human gastrointestinal carcinoids. Material and Methods: Primary carcinoids and hepatic carcinoid metastases (n = 8) were investigated for the presence of tryptophan hydroxylase, 5-hydroxytryptamine and chromogranin A. Results: Only one of the tumors examined was immunoreactive for tryptophan hydroxylase, as determined by immunohistochemical techniques and Western blot analysis All carcinoids expressed 5-hydroxytryptamine and chromogranin A. Conclusions: Carcinoids appear to be a heterogeneous group with respect to the expression of this monooxygenase. Based on these results it is proposed that other cells of the intestine are involved in the biosynthesis of 5-hydroxytryptamine precursors taken up by carcinoid tumor cells
Tryptophan hydroxylase and 5-hydroxytryptamine in carcinoids of the gastrointestinal tract
No full textBackground: Tryptophan hydroxylase is the enzyme that catalyzes the formation of 5-hydroxy-L-tryptophan which is the initial and rate-limiting enzyme in the biosynthesis of 5-hydroxytryptamine (serotonin). The aim of this study was to analyze the differential expression of tryptophan hydroxylase and 5-hydroxytryptamine in human gastrointestinal carcinoids. Material and Methods: Primary carcinoids and hepatic carcinoid metastases (n = 8) were investigated for the presence of tryptophan hydroxylase, 5-hydroxytryptamine and chromogranin A. Results: Only one of the tumors examined was immunoreactive for tryptophan hydroxylase, as determined by immunohistochemical techniques and Western blot analysis All carcinoids expressed 5-hydroxytryptamine and chromogranin A. Conclusions: Carcinoids appear to be a heterogeneous group with respect to the expression of this monooxygenase. Based on these results it is proposed that other cells of the intestine are involved in the biosynthesis of 5-hydroxytryptamine precursors taken up by carcinoid tumor cells
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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