1,720,960 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
Combining Optogenetics and fMRI to Study Cerebral Networks in Animal Models
No full textFunctional magnetic resonance imaging is a well-established technique to examine brain activity and networks in animal models. In contrast to electrophysiology, optogenetics enables the control of specific cell types. A second advantage is that optogenetic stimulation can trigger excitatory as well as inhibitory effects.
This study investigated optogenetic manipulation of neuronal activity and connectivity changes in mice and rats, using fMRI as an analytical method. The work addresses (1) glutamate release in mice and its use as a neurotransmitter and (2) oxytocin release in rats and its impact on neuronal networks. In fMRI, changes of metabolism and blood flow are described by the hemodynamic response function. The influence of the optogenetic stimulation on the hemodynamic response function was examined and characterized for both species.
In the first part, glutamatergic neurons in the left hippocampus of mice were optogenetically stimulated via channelrhodopsin-2. Sham animals, without virus injection, were used as a control group to study unspecific effects induced by the laser stimulation. In transgenic (α-CamKII-Cre) mice, the direct hippocampal activation was investigated as well as its projections to other regions. Additionally, the impact of the dorsal-ventral position of the optical fiber on the hippocampal-prefrontal projections was investigated.
We could demonstrate that the hemodynamic response measured in the hippocampus of mice reached its maximum earlier compared to the hemodynamic response function in humans. An explanation for this observation may be the smaller body size and the faster metabolism of mice. A highly significant increase of the BOLD signal was found for the optogenetic stimulation of glutamatergic neurons in the left hippocampus and its projecting areas, like the contralateral hippocampus and prefrontal regions. Furthermore, a negative correlation of prefrontal activation and the fiber depth was measured, which may be explained by the larger amount of stimulated neurons.
In the second part, we optogenetically stimulated oxytocin-releasing neurons either in the amygdala or in the paraventricular nucleus of rats. We hypothesize that changes in the oxytocin associated networks of the basal ganglia and the olfactory system should result from the optogenetic stimulation. Long-term changes in connectivity were investigated. Therefore, changes in correlations between different brain regions were calculated using the resting-state measurements before and after the optogenetic stimulation. Moreover, seed regions of defined functional networks were determined and voxel-based changes in resting-state correlation to the seed region were investigated. Additionally, short-term connectivity changes were examined in a psychophysiological interaction analysis as well as the direct activation induced by the laser stimulation.
We found that both channelrhodopsin-2 groups showed increased connectivity in the olfactory and basal ganglia networks compared to the control group. However, no short-term network changes were observed comparing the laser on and laser off condition. This might be explained by the hormonal characteristics of oxytocin, leading to a more global and prolonged response.
To summarize, this thesis demonstrates the successful combination of optogenetics and fMRI as a tool for basic neuropsychiatric research. It proves the successful manipulation, not only of single neurons, but also of neuronal networks in vivo by optogenetic stimulation
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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