1,720,968 research outputs found
Anatomical and functional characterization of neocortical circuits involved in transforming whisker sensory processing into goal-directed licking
Full text linkThe choice of an action upon perception of an external stimulus, arriving at a sensory organ of an animal, depends on previous experiences and outcomes throughout its life. In the rodent brain, the underlying mechanisms involved in simple sensorimotor transformations, such as the detection of a whisker stimulus through goal-directed licking, still remain largely unknown. In this thesis, using as a model the mouse somatosensory system, I explored the anatomical and functional properties of neuronal circuits at different stages of this cortical processing. To start with, using state-of-the-art viral tracing techniques, I investigated the thalamocortical circuits relaying sensory signals to the primary and secondary whisker somatosensory cortices (wS1, wS2). Challenging the "classical" views, the results indicated two streams of information carrying whisker-selective tactile signals. The principal trigeminal nucleus (Pr5) innervates the ventral posterior medial nucleus of the thalamus (VPM) and finally reaching layer 4 of wS1 while the spinal trigeminal nucleus (Sp5) through the rostral part of the posterior medial (POm) thalamus drives the layer 4 of wS2. Finally, a caudal part of the POm, which does not receive brainstem input, innervates layer 1 and layer 5A. Apart from their anatomical differences, those pathways conveyed distinct whisker sensory signals during goal-directed behaviors. Afterwards, I studied the cortical control of jaw and tongue movements during licking for rewards, using multisensory and multimotor whisker detection tasks. The data revealed a frontal tongue-jaw primary motor area (tjM1) which is necessary and encodes for directional licking, independently of the sensory stimulus type, shedding light on how the neocortex orchestrates the main motor output of the animal. Subsequently, I focused on changes in the L2/3 neuronal networks of wS1 after learning of a whisker stimulus. Using as a benchmark a novel "fast" learning and reward-dependent whisker detection task, I carried out inactivations of wS1 during different stages of learning and chronic two-photon (2P) calcium imaging in the L2/3 of the C2 barrel column. The inactivation results indicated that wS1 is indispensable for the acquisition of the novel stimulus and the execution of the task at expert levels. Moreover, the neural data suggested a learning-induced and "long-lasting" enhancement in the whisker sensory responses even when animals were unmotivated to lick. At a network level, a re-organization of the neuronal circuits was observed at different timescales with some of the alterations accompanying the rapid changes in the animal behavior. Additionally, the changes in the whisker sensory responses of neurons in wS1, after learning, were projection-pathway specific with wS2-projecting neurons showing higher whisker responses than whisker primary motor cortex (wM1)-projecting ones. In the final part, acknowledging the importance of a better characterization of the cortical-cortical communication of wS1, I described recent technical advancements in neuronal reconstructions. In vivo single-cell electroporation combined with 2P tomography and registration to a digital atlas, demonstrated the diversity of the projection targets of neurons in the L2/3 of wS1. Overall, I presented different results which contribute to a pre-existing body of research and help to decipher fundamentals and yet highly complex neural computations of the mammalian brain.LSEN
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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