1,720,991 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
Agonist activity of N-Desmethylclozapine, a major clozapine metabolite, at delta opioid receptors.
No full textIn the present study we report that N-desmethylclozapine (NDMC), a pharmacologically active metabolite of the atypical antipsychotic clozapine (CLOZ), acts as a selective and efficacious agonist at ð-opioid receptors. In Chinese hamster ovary (CHO) cells stably expressing the human ð-opioid receptor (CHO/DOR), NDMC behaves as a full agonist in stimulating [35S]GTPγS binding and in inhibiting cyclic AMP formation. In radioligand binding assays, NDMC inhibits [3H]naltrindole binding to CHO/DOR membranes with competition curves that are modulated by guanine nucleotides in an agonist-like manner. Estimation of intrinsic efficacies indicates that NDMC has an efficacy value equal to ~ 80% of that of the full ð-opioid receptor agonist DPDPE, whereas CLOZ and the other CLOZ metabolite clozapine N-oxide display a much lower efficacy. NDMC exhibits poor agonist activity at the k-opioid receptor and is inactive at the μ-opioid and NOP receptors. In NG108-15 cells, NDMC inhibits cyclic AMP formation and stimulates ERK1/2 phosphorylation by acting on ð-opioid receptors. Moreover, long-term exposure to NDMC causes desensitization of ð agonist-induced responses. In membranes of different rat brain regions, NDMC stimulates [ 35 S]GTPγS binding and regulates adenylyl cyclase activity and these effects are potently antagonized by naltrindole. These data suggest that the unique property of NDMC to activate ð-opioid receptors may contribute to the clinical actions of the atypical antipsychotic CLOZ
Stimulation of proteinase-activated receptors 1 and 2 induces neurodegeneration in the rat olfactory system.
No full textAlterations in the olfactory system and impairment of olfactory function have been reported in several neurodegenerative diseases, such as Alzheimer’ s and Parkinson’s diseases . The participation of proteinase activated receptors (PARs) in these neuropathological conditions has been postulated, but little is known on the expression and functional activity of PARs in the olfactory system. By using pharmacological, immunological and immunofluorescence techniques, we studied the presence, the signaling properties and cellular actions of PAR1 and PAR2 in the rat main olfactory bulb and in primary cultures of olfactory bulb and olfactory sensory neurons. PAR1 and PAR2 receptor activity was predominantly expressed in the olfactory nerve-glomerular cell layer (ON-GL), where selective peptide agonists inhibited cyclic AMP formation and stimulated [35S]GTPγS binding, phosphoinositide hydrolysis, CaMKII phosphorylation and Rho activation. Nanomolar concentrations of thrombin and trypsin mimicked the actions of the peptide agonists. Olfactory bulb deafferentation by lesion of the olfactory mucosa caused a reduction of PAR1 and PAR2 receptor activity in ON-GL associated with a loss of olfactory marker protein and type III adenylyl cyclase immunoreactivities, suggesting the possible localization of a receptor population on olfactory nerve terminals. In primary cultures of olfactory bulb cells and olfactory neuroepithelial cells, exposure to either serine proteinases or selective peptide agonists caused a rapid neurite retraction and a long-term decrease of cell viability. Immunofluorescence analysis showed the presence of PAR1 and PAR2 in neurons and glial cells of olfactory bulb and in olfactory sensory neurons. These data provide the first evidence that PAR1 and PAR2 are expressed and functional in different structures of the olfactory system and suggest the possible involvement of the receptor in neurodegenerative processes affecting the olfactory function
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
Allosteric modulation of GABA(B) receptor function in human frontal cortex.
No full textIn the present study, the effects of different allosteric modulators on the functional activity of gamma-aminobutyric acid (GABA)B receptors in membranes of post-mortem human frontal cortex were examined. Western blot analysis indicated that the tissue preparations expressed both GABA(B1) and GABA(B2) subunits of the GABA(B) receptor heterodimer. In [35S]-GTPgammaS binding assays, Ca2+ ion (1 mM) enhanced the potency of the agonists GABA and 3-aminopropylphosphinic acid (3-APA) and that of the antagonist CGP55845, but not that of the GABA(B) receptor agonist (-)-baclofen. CGP7930 (2,6-di-t-Bu-4-(3-hydroxy-2,2-dimethyl-propyl)-phenol), a positive allosteric modulator of GABA(B) receptors, potentiated both GABA(B) receptor-mediated stimulation of [35S]-GTPgammaS binding and inhibition of forskolin (FSK)-stimulated adenylyl cyclase activity. Chelation of Ca2+ ion by EGTA reduced the CGP7930 enhancement of GABA potency in stimulating [35S]-GTPgammaS binding by two-fold. Fendiline, also reported to act as a positive allosteric modulator of GABA(B) receptors, failed to enhance GABA stimulation of [35S]-GTPgammaS binding but inhibited the potentiating effect of CGP7930. The inhibitory effect was mimicked by the phenothiazine antipsychotic trifluoperazine (TFP), but not by other compounds, such as verapamil or diphenydramine (DPN). These data demonstrate that the function of GABA(B) receptors of human frontal cortex is positively modulated by Ca2+ ion and CGP7930, which interact synergistically. Conversely, fendiline and trifluoperazine negatively affect the allosteric regulation by CGP7930
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