1,720,967 research outputs found
Differential role of striatal and nigral D1receptors in the expression of L-DOPA induced dyskinesia and its neurochemical correlates
No full textDifferential role of striatal and nigral D1receptors in the expression of L-DOPA induced dyskinesia and its neurochemical correlates
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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
Transcriptome analysis in a rat model of L-dopa-induced dyskinesia
No full textWe have examined the pattern of striatal messenger RNA expression of over 8000 genes in a rat model of levodopa (L-DOPA)-induced dyskinesia and Parkinson disease (PD). 6-Hydroxydopamine (6-OHDA)-lesioned rats were treated with L-DOPA or physiological saline for 22 days and repeatedly tested for antiakinetic response to L-DOPA and the development of abnormal involuntary movements (AIMs). In a comparison of rats that developed a dyskinetic motor response to rats that did not, we found striking differences in gene expression patterns. In rats that developed dyskinesia, GABA neurons had an increased transcriptional activity, and genes involved in Ca2+ homeostasis, in Ca2+ -dependent signaling, and in structural and synaptic plasticity were upregulated. The gene expression patterns implied that the dyskinetic striatum had increased transcriptional, as well as synaptic activity, and decreased capacity for energy production. Some basic maintenance chores such as ribosome protein biosynthesis were downregulated, possibly a response to expended ATP levels
Pharmacological validation of a mouse model of L-dopa-induced dyskinesia
No full textDyskinesia (abnormal involuntary movements) is a common complication of l-DOPA pharmacotherapy in Parkinson's disease, and is thought to depend on abnormal cell signaling in the basal ganglia. Dopamine (DA) denervated mice can exhibit behavioral and cellular signs of dyskinesia when they are treated with l-DOPA, but the clinical relevance of this animal model remains to be established. In this study, we have examined the pharmacological profile of l-DOPA-induced abnormal involuntary movements (AIMs) in the mouse. C57BL/6 mice sustained unilateral injections of 6-hydroxydopamine (6-OHDA) in the striatum. The animals were treated chronically with daily doses of l-DOPA that were sufficient to ameliorate akinetic features without inducing overt signs of dyskinesia upon their first administration. In parallel, other groups of mice were treated with antiparkinsonian agents that do not induce dyskinesia when administered de novo, that is, the D2/D3 agonist ropinirole, and the adenosine A2a antagonist KW-6002. During 3 weeks of treatment, l-DOPA-treated mice developed AIMs affecting the head, trunk and forelimb on the side contralateral to the lesion. These movements were not expressed by animals treated with ropinirole or KW-6002 at doses that improved forelimb akinesia. The severity of l-DOPA-induced rodent AIMs was significantly reduced by the acute administration of compounds that have been shown to alleviate l-DOPA-induced dyskinesia both in parkinsonian patients and in rat and monkey models of Parkinson's disease (amantadine, -47%; buspirone, -46%; riluzole, -33%). The present data indicate that the mouse AIMs are indeed a functional equivalent of l-DOPA-induced dyskinesia
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