1,720,985 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
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
Deciphering the embryo-maternal dialogue in the horse using an oviduct explant model
Get PDFTo date, in vivo derived equine embryos are of superior quality compared to those produced in vitro, in terms of morphology and ultrastructure, gene expression and developmental competence. This phenomenon confirms that current in vitro systems are deprived of particular essential maternal factors or signals and illustrates the importance of embryo-maternal interplay. So far, only very few signals involved in the embryo-maternal dialogue have been identified in the horse. Although in vivo models are the gold standard, it is difficult to investigate molecular processes within a relatively large space like the equine oviduct. It is for instance difficult to locate gametes and the embryo in the oviduct and to unravel local paracrine and autocrine events, which are essential in elucidating intra- and extracellular molecular pathways and processes. The general goal of this thesis was to gain insight in the embryo-maternal communication in the horse. To achieve this aim, the influence of steroids on the oviduct was in vivo investigated (CHAPTER 4). These effects were simulated in vitro (CHAPTER 5.1) by means of an optimized in vitro oviduct explant model (CHAPTER 3). The effect of steroids (CHAPTER 5.1) and embryos (CHAPTER 5.2) on oviduct explant’s gene expression was assessed. Next, as a step forward to the improvement of in vitro equine embryo culture, it was also investigated whether embryos in vitro benefit from culture at the mare’s body temperature (CHAPTER 6).
In CHAPTER 3.1, a culture system which sustains equine oviduct explants bordered by highly differentiated, glucose consuming, functional and intact epithelial cells showing vigorous ciliary activity during 6 days of culture was optimized. Only a negligible percentage (1–2%) of the cells in the explants showed features of apoptosis or necrosis and therefore, it could be concluded that the explants mimic the in vivo situation very closely. Although dark-cell degeneration, a hypoxia related type of cell death, was detected using TEM, the hypoxia marker genes HIF1A, GLUT1 and VEGFA were not upregulated in the culture system, even in culture at high oxygen concentrations. In an attempt to further unravel the origin of the dark cell degeneration, explants were cultured with and without foetal calf serum (FCS) or supplemented with serum replacement insulin-transferrin-selenium (ITS) in CHAPTER 3.2. It turned out that selenium increases while FCS decreases to some extent the incidence of explants showing dark cell degeneration.
In the horse no information is available concerning local steroid concentrations in the oviduct and their fluctuations during the oestrous cycle. Therefore in CHAPTER 4 the concentrations of progesterone, oestradiol, testosterone and 17-hydroxyprogesterone were determined in equine oviductal tissue by the highly powerful technique UHPLC-MS/MS whereas RIA was applied to measure steroids in oviductal fluid. Progesterone concentrations were high in oviductal tissue and fluid ipsilateral to the ovulation side during diestrus, whereas testosterone, and 17α-testosterone and 17-hydroxyprogesterone other steroid hormone concentrations were not influenced by the side of ovulation. The most plausible explanation for the elevated progesterone concentration in the ipsilateral oviduct of the mare is a combination of 1) the contribution from follicular fluid in the oviduct and the diffusion of follicular fluid steroids after ovulation; 2) a local transfer of steroids via blood or lymph, 3) local synthesis of progesterone in the oviduct which is confirmed by the expression of StAR, cytochrome P450scc and 3-beta-HSD, key enzymes in the progesterone synthesis, as well as aromatase, which is suggestive of local steroidogenesis; and, 4) the paracrine contribution from follicular cells.
In CHAPTER 5.1, preovulatory explants were stimulated with hormone concentrations as they prevail in the postovulatory stage and vice versa. The influence of these steroid hormones on the function (ciliary activity, glucose consumption and lactate production), the ultrastructure, the mRNA expression of a set of embryotrophic genes, the steroidogenic capacities and the progesterone receptor expression in the equine oviduct was assessed. Progesterone and 17β-oestradiol were able to modify ciliary activity, energy metabolism, gene expression, immunoreactive steroidogenic enzyme expression and progesterone receptor expression in oviductal explants in vitro. Furthermore, PAI1, PLAU, GLUT1, CSF1, TGFA and MMP2 were shown to be upregulated in the oviductal epithelium originating from mares in the postovulatory cycle stage. Moreover, preovulatory oviduct explants, primed by steroids in vivo, are responsive to in vitro stimulation with postovulatory oviductal progesterone and 17β-oestradiol concentrations and approach the in vivo condition at the level of functionality and gene expression. This endorses that our explant model remains functional and responsive for at least three days (CHAPTER 3). In addition, it turned out that oviduct explants are capable of producing large amounts of progesterone in vitro and are able to remove considerable amounts of oestrone, 17β-oestradiol and testosterone from the culture medium. This confirms again the functional integrity of the culture system.
The oviductal environment represents the optimal environment for early embryo development. Supposing that oviductal cells provide specific mitogenic factors that would normally be present in the oviduct, or non-specific factors that improve the culture environment such as reduction of oxygen tension, removal of waste products or provision of substrates and co-factors, we cultured equine zygotes, obtained by ICSI, with and without equine oviduct explants in CHAPTER 5.2. To elucidate the role of developing embryos on the modulation of gene expression in the oviduct, we unraveled the response of the same set of embryotrophic genes as used in CHAPTER 5.1 in oviductal cells cultured together with equine putative zygotes (CHAPTER 3). Co-culture with equine embryos stimulated the expression of the embryotrophic genes TIMP1, PTGER2, TGFA, MMP2, CSF1 and PAI1 in the oviduct explant, which have been described to be involved in embryo transport, and in stimulating embryonic development and quality, and they modulate oviductal matrix turnover. Co-culture did not affect ciliary activity or viability of oviduct explants.
In an attempt to further improve embryo culture conditions, it was investigated in CHAPTER 6 if oocyte maturation, cleavage, blastocyst rate and blastocyst diameter could be improved when applying the physiological body temperature of the mare (37.3 °C) rather than the conventional 38.5°C. Cytoplasmic maturation does not differ in both groups. The size of blastocysts was smaller in the oocytes matured and embryos cultured at 37.3°C compared with the matured and cultured at 38.5°C. Since blastocyst size is a parameter of embryo viability, culture at 38.5°C may be recommended rather than culture at 37.3°C.
In the final CHAPTER 7 the general discussion and conclusions are presented. Our findings indisputably demonstrate that the equine oviduct is able to respond to both steroids and embryonic signals in vivo and in vitro and that our oviduct explant model is an excellent model to further unravel the embryo-maternal interplay in the horse
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