1,720,954 research outputs found
FOXG1 modulates LINE1 activity in the developing embryonic neocortex
No full textFoxg1 is an ancient transcription factor mastering telencephalic development. mLINE1 is a large retrotransposon family contributing to plasticity of neuronal genome. All mLINE1's share
putative Foxg1 binding elements. Moreover, it is known that mLINE1 transcription is upregulated in postnatal glutamatergic progenitors, whereas Foxg1 declines in embryonic progenitors of the same lineage. Based on that, we predicted that Foxg1 might limit mLINE1 expression (and activity).
Here we tested such prediction, with particular attention to its cellular and molecular features.
First, as expected, we found that mLINE1-mRNA encoded by all three retro-transposition competent subfamilies (A, Gf and Tf) was increased in Foxg1-loss-of-function (-LOF) mouse pups.
Next, to model articulation of Foxg1-dependent LINE1 regulation, we developed a dedicated set of in vitro preparations, representing early-, mid- and late-phases of neuronogenesis. By profiling this set, we detected a progressive increase of LINE1-mRNA levels from neural stem cells (NSCs) up to neurons (Ns). Then, taking advantage of these preparations, we manipulated Foxg1 levels at different stages of the neuronogenic progression, according to specific neural cell type restrictions.
We mapped changes in Foxg1 protein levels evoked of these manipulations, and we evaluated LINE1-mRNA levels originating from them. Integrated analysis of results pointed to selective mLINE1 repression by Foxg1 in neuronal progenitors (NPs) and Ns.
To assess if Foxg1 modulation of mLINE1-mRNA takes place via direct gene trans-repression, we evaluated Foxg1 enrichment at mLINE1 loci via ChIP. In wild type cultures, Foxg1 was enriched
along the whole body of mLINE1's belonging to all three subfamilies. However, this enrichment was restricted to mid-neuronogenic cultures, and not detectable in early-neuronogenic ones, ruling out Foxg1 modulation of mLINEs in NSCs. Intriguingly, such enrichment was more pronounced upon
artificial Foxg1 overexpression, suggesting that Foxg1 may physiologically tune mLINE1 transcription. Furthermore, we found that Foxg1 overexpression in mid-neuronogenic cultures elicited a generalized decrease in transcription-activating marks (H3K4me3) and an increase of repressing ones (H3K9me3). These phenomena occurred at all mLINE1 subfamilies loci, suggesting
that Foxg1 largely impacts on mLINE1 transcription via modifications of the corresponding epigenetic landscape.
Next, we moved to Foxg1 control (if any) of cellular mLINE1-DNA content. First, we found that this content was upregulated by about 25% in Tubb3+, post-mitotic wild type neurons
compared to their ancestors, in a retro-transcription-dependent way. Next, paradoxically, we also discovered that Foxg1 down-regulation elicited a co-linear reduction in mLINE1-DNA content,
suggesting that Foxg1 is strictly needed to sustain physiological amplification of such DNA. This phenomenon was observed in vivo as well as in vitro. Puzzingly, Foxg1 overexpression led to variable outcomes, increased, unchanged or decreased mLINE1-DNA content, depending on different promoters driving it. Differential sensitivity of mLINE1 transcription and retro-transcription to Foxg1 levels could account for these phenomena. Finally, mechanisms underlying Foxg1 impact on mLINE1
DNA content were not yet investigated, however, we got evidence that direct Foxg1 protein/mLINE1-mRNA interaction could underlie it
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
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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