1,720,986 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
Label-free, real-time on-chip sensing of living cells via grating-coupled surface plasmon resonance
No full textThe application of nanotechnologies to address biomedical questions is a key strategy for innovation in biomedical research. Among others, a key point consists in the availability of nanotechnologies for monitoring cellular processes in a real-time and label-free approach. Here, we focused on a grating-coupled Surface Plasmon Resonance (GC-SPR) sensor exploiting phase interrogation. This sensor can be integrated in a microfluidic chamber that ensures cell viability and avoids cell stress. We report the calibration of the sensor response as a function of cell number and its application to monitor cell adhesion kinetics as well as cell response to an external stimulus. Our results show that GC-SPR sensors can offer a valuable alternative to prism-coupled or imaging SPR devices, amenable for microfluidic implementation
Acethylcholine esterase inhibitor tacrine reduced extinction responding, but not self-administration and drug discrimination, of nicotine or amphetamine in rats
No full textCholinergic transmission may play an important role in the mediation of drug addiction. Acethylcholine esterase (AChE) inhibitors (AChE-I) by increasing acethylcholine brain concentrations may offers a feasible tool to better understand the role of ACh in drug addiction behaviours. The aim of the series of experiments here described is to study the effect of AChE-I tacrine on three protocols of nicotine or d-amphetamine addictive behaviour in Sprague Dawley rats: drug discrimination, drug self administration and extinction responding.
When different groups of rats met the criteria for d-amphetamine (0.6 mg/Kg IP) or nicotine (0.2 mg/Kg SC) discrimination from vehicle in a two-lever drug discrimination task, tacrine (1.25 mg/Kg, IP) was tested for generalization. The effect of tacrine pre-treatment (0.32 mg/Kg IV) on nicotine or amphetamine reinforcing properties was studied in two groups of rats trained to a schedule of FR2:d-amphetamine (0.1 mg/kg/infusion) or nicotine (0.03 mg/kg/infusion) IV self administration (1-h session). Finally, tacrine (0.32 mg/Kg IV) effect on responding on first extinction session was tested when amphetamine or nicotine IV infusions were omitted.
Nicotine or amphetamine discriminative stimulus did not generalize with tacrine. Tacrine pre-treatment did not induce any change on nicotine or amphetamine self-administration. However, when given on the first day of extinction, tacrine induced a significant decrease of nicotine-paired (-63%, P<0.05) and a trend to decrease of amphetamine-paired (-50%, P=0.06 ) -lever responding vs. corresponding baseline.
These findings showed that inhibition of AChE with tacrine did not change interoceptive and reinforcing stimuli properties of nicotine or amphetamine, but suggest a potential inhibitory effect on learning of the extinction responding. Further studies are needed to test tacrine on reinstatement to amphetamine or nicotine-seeking behaviour
MiR 34b Promoter Methylation and Regulation of CREB Expression In Myeloid Transformation
No full textDispelling 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
Modulation of miR-210 alters phasing of circadian locomotor activity and impairs projections of PDF clock neurons in Drosophila melanogaster
No full textSingle microRNAs are usually associated with hundreds of putative target genes that can influence multiple phenotypic traits in Drosophila, ranging from development to behaviour. We investigated the function of Drosophila miR-210 in circadian behaviour by misexpressing it within circadian clock cells. Manipulation of miR-210 expression levels in the PDF (pigment dispersing factor) positive neurons affected the phase of locomotor activity, under both light-dark conditions and constant darkness. PER cyclical expression was not affected in clock neurons, however, when miR-210 was up-regulated, a dramatic alteration in the morphology of PDF ventral lateral neuron (LNv) arborisations was observed. The effect of miR-210 in shaping neuronal projections was confirmed in vitro, using a Drosophila neuronal cell line. A transcriptomic analysis revealed that miR-210 overexpression affects the expression of several genes belonging to pathways related to circadian processes, neuronal development, GTPases signal transduction and photoreception. Collectively, these data reveal the role of miR-210 in modulating circadian outputs in flies and guiding/remodelling PDF positive LNv arborisations and indicate that miR-210 may have pleiotropic effects on the clock, light perception and neuronal development
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