1,720,981 research outputs found
The role of epigenetic processes in bone development
No full textOsteoporosis is a progressive systemic skeletal disease caused by an imbalance of the bone remodelling process leading to a net loss of bone. Peak bone mass, the amount of bone tissue accrued at the end of skeletal maturation, is a strong predictor of osteoporotic fracture risk in later life. Genotype has been suggested to account for around 10% of the variance in peak bone mass, with increasing evidence suggesting the remaining variance may be explained by environmental exposures in prenatal life, such as maternal vitamin D status. The influence the prenatal environment on the trajectory of skeletal development in postnatal life has been suggested to occur through epigenetic mechanisms. Consistent with this, candidate gene studies have identified epigenetic marks in birth tissues predictive of later bone outcomes.This project aimed to: (i) identify DNA methylation signatures at birth associated with childhood BMC and BMD, and (ii) determine whether maternal vitamin D supplementation altered DNA methylation in genes linked to improved BMC or BMD in postnatal development. To investigate these aims epigenome-wide association studies (EWAS) were performed using the Illumina Infinium MethylationEPIC Beadchip (EPIC) array to interrogate birth tissue DNA from the Maternal Vitamin D Osteoporosis Randomised Control Study (MAVIDOS RCT) and the Southampton Women’s Survey (SWS) studies along with umbilical cord mesenchymal stromal cells (UC-MSCs).EWAS analysis identified methylation signatures at birth associated with childhood bone outcomes in both the MAVIDOS RCT and SWS studies. Within each study the top dmCpGs at each age group showed overlap between BMC and BMD outcomes, but with less overlap observed between age groups or between studies, indicating a tissue and age specificity to these changes. In addition, EPIC array interrogation of umbilical cord tissue DNA from the MAVIDOS RCT found maternal vitamin D supplementation induced significant differential methylation in three CpGs, including the potentially pro-osteogenic Solute Carrier Family 38 Member 10 and Tenascin C genes. The MAVIDOS RCT bone and intervention-related analyses together indicated differential methylation of multiple CpG sites in Protein Tyrosine Phosphatase Receptor Type N2 (PTPRN2), a gene involved in glucose homeostasis which also encodes miR-153, a negative regulator of insulin secretion and an anti-osteogenic factor in human bone marrow mesenchymal stromal cells. In the SWS cohort, differential methylation analysis of SWS umbilical cord blood DNA showed dmCpGs significantly associated with an insufficient maternal vitamin D status in late pregnancy. The most significant dmCpG was within Hexokinase 1, a rate-limiting gene in glycolysis. EWAS analysis of short-term vitamin D treated UC-MSCs also saw enrichment for dmCpGs in cellular respiration and glycolytic pathways.In this study we identified associations between methylation of birth tissues and postnatal skeletal growth into childhood. Whilst the functional implications of these changes are not yet known, these dmCpGs, after further replication and validation, could potentially act as age and tissue-specific prospective markers of postnatal bone growth, helping to identify those with a lower peak bone mass and so a greater risk for osteoporosis later in life. These findings also suggest maternal vitamin D supplementation induced DNA methylation changes within foetal tissues in prenatal life may have the potential to influence the development of bone in postnatal life through epigenetic mechanisms. The effects of vitamin D on the epigenome may also be indirect through differential regulation of PTPRN2 expression or through influence on glucose homeostasis, both of which may also have implications for skeletal development
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
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
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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