1,720,962 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
Role of Methylation in Modulating MAPK Signaling. Implications in Melanoma. Papel de la metilación como modulador de la señalización en MAPK. Implicaciones en melanoma.
Full text link1. General Overview
MTAP is a key enzyme in the methionine salvage pathway and controls the levels of methylthioadenosine (MTA). Lost of MTAP, which is frequent in melanoma, results in higher intra and extracellular MTA levels. As MTA is an inhibitor of methylation reactions within the cell, we decided to further investigate the role of methylation in the progression of cancer and how the main signaling pathway involved in melanoma (RAS-RAF-MEK-ERK pathway) can be affected in the presence or absence of methylation inhibitors.
2. Results
• Exogenous addition of MTA (and therefore blocking of methylation reactions) to melanoma cells increased total activity of the RAS-ERK pathway, highlighting a new role of methylation into controlling the amplitude of the signal transduction.
• We found out that PRMT5, a protein arginine methyl transferase enzyme, binds to CRAF, a key component of the RAS-ERK pathway. In vitro and in vivo experiments showed that PRMT5 methylates CRAF and thus modifies the pathway’s output. We identified CRAF arginine 563 as the target of PRMT5 methyl transferase activity. Furthermore, in vitro kinase assays and siRNA technology experiments showed that methylation at arginine 563 can modify the kinase activity of CRAF protein, therefore modulating the total activity of the RAS-ERK pathway.
• The previous results provided the first known evidence of methylation as a key modulator of the activity in MAPKs pathways, so we looked for a biological significance of this new regulatory mechanism. We used the well-established PC12 cell line system (EGF growth factor triggers proliferation whereas NGF promotes differentiation): as we had shown that PRMT5-catalyzed methylation can modify the kinase activity of the RAS-ERK pathway, we wondered whether this regulation could be part of a general mechanism controlling cell behavior. In order to test this, we tried to mimic the differentiating effect of NGF using EGF to activate the pathway in the presence of MTA or after PRMT5 siRNA. Interestingly, when triggering the cells with EGF after PRMT5 depletion or MTA treatment, they differentiated in a manner indistinguishable from that induced by NGF. Moreover, we observed that cells transfected with CRAFR563K mutant underwent differentiation, instead proliferation, when treating the cells with EGF. Together these data demonstrate a central role of methylation in the growth factors-elicited biological responses.
• RAS-ERK pathway plays a key role into controlling development and maintenance of melanoma. There is a clear correlation between the activity of the pathway and melanoma growth and proliferation, so we wondered how methylation reactions could affect melanoma progression. In order to address this question we performed in vitro assays in a variety of melanoma cell lines and we found out that MTA inhibited cell proliferation and viability. Next, we injected these cells in a melanoma xenograft mouse model to induce tumoral growth: mice treated with MTA showed a significant decrease (47%) in the tumor volume with no apparent toxic effects, indicating that MTA is effective blocking melanoma in vivo tumor growth. Besides, we have been able to proof that MTA inhibitory effect was due to citostatic MTA capability rather than a pro-apoptotic effect.
3. Discussion
In our reports we demonstrate that methylation is an important mechanism modulating signal transduction through the RAS-ERK pathway in response to specific growth factors. Our data implicate a specific PRMT5 methylation motif (GRG) that is conserved in all RAF proteins and we demonstrate that methylation appears to be a critical posttranslational modification controlling the RAF input to the downstream activity.
We have shown that methylation is controlling ERK signal amplitude in response to specific growth factors in cells from different species. We also have identified PRMT5 as the protein performing the methylation reaction. Our results provide clues about the possible fine-tuning mechanism by which methylation regulates the total signal, indicating that PRMT5 methylates CRAF at arginine 563.
Our research shows that protein arginine methylation is a universal mechanism that modulates signal transduction in response to specific growth factors and we demonstrate that PRMT5 is the methyltransferase involved in the process regulating the total CRAF kinase activity within the pathway. The mechanism we describe provides the means by which cells can modulate the time profile of ERK activation for which a particular biological response is evoked. More importantly, because cancer cells tend to heavily rely on oncogenic signalling through the RAS-RAF-MEK-ERK pathway, this additional level of signal transduction regulation identifies novel candidate targets for therapeutical intervention.
Finally, we have tested the potential of the methylation inhibitor MTA regarding to tumour progression: our experiments have demonstrated that MTA inhibits, in vitro, cell proliferation and viability in a dose dependent manner in a variety of mouse and human melanoma cell lines. Importantly, MTA was also effective inhibiting in vivo tumour growth in a mouse melanoma xenograft model. In summary, here we show the therapeutic potential of the natural occurring nucleoside MTA and we demonstrate that MTA can inhibit melanoma cell proliferation and in vivo tumour growth at non-toxic rates, supporting the use of MTA in antitumoral therapies and presenting protein methylation reactions as potential targets when developing new antitumoral strategies
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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