1,724,066 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
DENDRITIC SPINE DENSITY OF CA1 PYRAMIDAL CELLS IN THE HIPPOCAMPUS OF AGED RATS - EFFECTS OF PHOSPHATIDYLSERINE ADMINISTRATION
No full textTemporal sequence of changes in central noradrenergic system of rat after prolonged antidepressant treatment: Receptor desensitization and neurotransmitter interactions
No full textIt has been shown that different receptor components may be involved in the adaptive changes occurring in noradrenergic (NE) neurones after prolonged periods of exposure to antidepressant drugs. In this report the desensitization of NE-coupled adenylate cyclase (NE-AC), β-adrenergic receptors and [3H]imipramine ([3H]-IMI or [3H]desipramine ([3H]DMI) binding sites have been temporally correlated with in vivo changes of NE utilization. Normetanephrine (NMN) was measured as indicator of NE synaptic events involved in antidepressant action. Concentrations of normetanephrine were increased after acute desipramine (DMI), viloxazine and mianserin administration. Following 3 days of treatment, the antidepressant-induced increase of normetanephrine became tolerant and NE neurones were resistant to the antidepressant effect until the 15th day of treatment. After two weeks, DMI elicited a significant decrease in the content of normetanephrine. A different pattern of changes has been found in the temporal modification of [3H]IMI recognition sites, β-adrenoceptors and NE-AC activity after chronic DMI treatment. Binding sites and receptors were down regulated after 10 days of treatment preceding the decrease in normetanephrine content. No down-regulation was observed in [3H]-DMI binding sites. Studies on the effects of antidepressants during brain maturation revealed that the mechanisms which cause desensitization of β-receptors and [3H]-IMI binding sites appear in the early stages of postnatal life. Since [3H]-IMI and [3H]-DMI recognition sites have been shown to be located on serotonergic (5-HT) and noradrenergic neurones respectively, the interactions between NE and 5-HT neurones could represent possible mechanisms implicated in receptor desensitization. The experiments presented involving lesions of 5-HT neurones have clearly demonstrated that NE release in rat cerebral cortex is under a tonic serotonergic influence. Alterations in the chemico-physical properties of the synaptic membranes might be also taken in consideration for the mechanisms underlying receptor modulation. In fact, evidence is provided that in neural tissue phospholipid methylation can be affected. In conclusion, the temporal sequence of changes in cortical noradrenergic neurones, after chronic antidepressant treatment, has demonstrated that integrated mechanisms are operative for the function of the overall system. © 1983
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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