1,720,965 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
BACE1 expression and activity: relevance in Alzheimer’s disease
No full textA turning point of research in Alzheimer's disease was undoubtedly the discovery of BACE1, the amyloid-beta precursor protein-cleaving enzyme that initiates the generation of amyloid-beta, the peptide strongly suspected to be responsible for neuronal malfunction and death. Several research groups started a race to identify the best inhibitor of BACE1 activity. On the other hand, basic researchers are evaluating the changes in BACE1 expression and activity with the aim to better understand the pathogenetic process of the disease. Along this second line of research, in the last few years many important results have been reported in various experimental models, as well as in Alzheimer's disease patients. As a consequence, new pathogenetic paradigms have been developed. We have reviewed these reports trying to highlight contrasting viewpoints, data awaiting final confirmation, and promising perspectives
Translational control of Scamper expression via a cell-specific internal ribosome entry site
No full textTranslational regulation of BACE-1 expression in neuronal and non-neuronal cells
No full textAs the main beta-secretase of the central nervous system, BACE-1 is a key protein in the pathogenesis of Alzheimer's disease. Excessive expression of the protein might cause an overproduction of the neurotoxic beta-amyloid peptide. Therefore, a tight regulation of BACE-1 expression is expected in vivo. In addition to a possible transcriptional control, the BACE-1 transcript leader contains features that might constitute mechanisms of translational regulation of protein expression. Moreover, recent work has revealed an increase of BACE-1 protein and beta-secretase activity in some Alzheimer's disease patients, although a corresponding increase of transcript has not been reported. Here we show that BACE-1 translation could be modulated at multiple stages. The presence of several upstream ATGs strongly reduces the translation of the main open reading frame. This inhibition could be overcome with conditions that favour skipping of upstream ATGs. We also report an alternative splicing of the BACE-1 transcript leader that reduces the number of upstream ATGs. Finally, we show that translation driven by the BACE-1 transcript leader is increased in activated astrocytes independently of the splicing event, indicating yet another mechanism of translational control. Our findings might explain why increases in BACE-1 protein or activity are reported in the brain of Alzheimer's disease patients even in the absence of changes in transcript levels
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
ARGONAUTE2 cooperates with SWI/SNF complex to determine nucleosome occupancy at human Transcription Start Sites.
Get PDFArgonaute (AGO) proteins have a well-established role in post-transcriptional regulation of gene expression as key component of the RNA silencing pathways. Recent evidence involves AGO proteins in mammalian nuclear processes such as transcription and splicing, though the mechanistic aspects of AGO nuclear functions remain largely elusive. Here, by SILAC-based interaction proteomics, we identify the chromatin-remodelling complex SWI/SNF as a novel AGO2 interactor in human cells. Moreover, we show that nuclear AGO2 is loaded with a novel class of Dicer-dependent short RNAs (sRNAs), that we called swiRNAs, which map nearby the Transcription Start Sites (TSSs) bound by SWI/SNF. The knock-down of AGO2 decreases nucleosome occupancy at the first nucleosome located downstream of TSSs in a swiRNA-dependent manner. Our findings indicate that in human cells AGO2 binds SWI/SNF and a novel class of sRNAs to establish nucleosome occupancy on target TSSs
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