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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
Funktionale Rolle des polysalyierten neuralen Zellerkennungsmoleküls für Furcht-Konditionierung bei Mäusen (Mus musculus L., 1758)
Get PDFConsiderable progress has been made in uncovering the numerous functions of the neural cell adhesion molecule (NCAM) and its associated carbohydrate, polysialic acid (PSA), in ontogenetic development and in synaptic plasticity, learning and memory in the adult. Perturbation of NCAM functions by ablation of NCAM or by disruption of NCAM-mediated interactions in vitro or in vivo impaired synaptic plasticity in the hippocampus, fear conditioning, induced amnesia in a passive avoidance task, and caused spatial memory deficits. The mechanisms underlying action of NCAM and PSA at different phases of learning and memory consolidation are, however, unknown.
To investigate the contributions of PSA versus the extracellular domain of the NCAM glycoprotein backbone on learning we acutely injected NCAM, PSA-NCAM and PSA into the dorsal hippocampus of wild-type mice at different phases of auditory fear conditioning. As an internal control that injections into the hippocampus would not have unspecific effects on hippocampus-independent forms of learning, we used a fear conditioning paradigm in which an animal was simultaneously subjected to hippocampus-independent learning of tone and hippocampus-dependent learning of context. Only PSA, either attached to NCAM or alone, but not NCAM, injected before training, impaired formation of hippocampus-dependent contextual memory, as measured by the freezing response. Consolidation of contextual memory was affected only by PSA-NCAM when injected during its late, but not its early phases. None of the tested compounds disturbed extrahippocampal cued memory. Mice lacking the polysialyltransferase (ST8SialV/PST) responsible for attachment of PSA to NCAM in adulthood showed a mild deficit only in hippocampal contextual learning, when compared to NCAM deficient mice that were disturbed in both contextual and cued memories. Formation of contextual memory in NCAM deficient mice could be restored by pre-training injection of PSA-NCAM into the hippocampus, suggesting that a mechanism for PSA-NCAM function in learning is not mediated by modulation of NCAM-NCAM homophilic interactions but rather through its heterophilic partners. These in vivo results are supported by in vitro data showing the inhibitory effects of PSA on long-term potentiation (LTP) in the CA1 region of the hippocampus in wild-type mice and restorative effects of PSA on impaired CA1 LTP in NCAM deficient hippocampal slices. In summary, our data support the view that polysialylated NCAM is involved in both formation and late consolidation of contextual memory, and supports synaptic plasticity.
By using tamoxifen-inducible Cre-recombinase LoxP system - which allowed us to induce temporally controlled ablation of the NCAM gene in the brain of adult mice – we show that NCAM is required for formation and/or retention of hippocampus-dependent contextual memory, whereas amygdala-contingent cued memory is less dependent on inducible ablation of NCAM. These results are intriguing since constitutive prenatal NCAM ablation causes both hippocampal- and amygdala-dependent deficits in fear conditioning, and thus raise the question whether NCAM is critical for development of the amygdala, or the levels of NCAM expression in the amygdala after inducible ablation remain sufficiently high to mediate its functions.
Strikingly, severe cognitive deficits in learning and memory of contextual and cued information in NCAM deficient mice could be rescued by facilitation of activity of the NMDA subtype glutamate receptors via systemic administration of D-cycloserine, as an agonist of the glycine site of these receptors. These results correspond to data from ongoing in vitro studies demonstrating a rescue of CA1 LTP in NCAM or PSA-deficient hippocampal slices by D-cycloserine. Thus, we suggest that a loss of NCAM and/or PSA leads to a deficit in NMDA receptor function during induction of synaptic plasticity and fear learning. Since lower concentrations of D-cycloserine were sufficient to restore levels of hippocampus-dependent contextual memory as compared to amygdala-based cued fear memory, there may be interesting differences in regulation of NMDA receptors by PSA-NCAM in the hippocampus and amygdala. The significance of these findings is underscored by studies uncovering a genetic link between schizophrenia and mutations in the polysialyltransferase ST8SiaII/STX, and a deficit in PSA and overproduction of soluble NCAM in schizophrenic brains.In der Erforschung der verschiedenen Funktionen des neuralen Zellerkennungsmoleküls (NCAM) und des assoziierten Carbohydrats Polysialylsäure (PSA) wurden große Fortschritte in den Bereichen ontogenetische Entwicklung, synaptische Plastizität sowie Lernen und Gedächtnis im erwachsenen Tier gemacht. Die Störung der Funktionen von NCAM durch die Entfernung des Moleküls oder die Unterbrechung von NCAM-vermittelten Interaktionen in vitro oder in vivo beeinträchtigt die synaptische Plastizität im Hippocampus und die Furcht-Konditionierung, verursacht Amnesie in einer passiven Vermeidungsaufgabe und bewirkt Defizite im räumlichen Gedächtnis. Die Mechanismen, die den Aufgaben von NCAM und PSA in unterschiedlichen Phasen von Lernen und Gedächtniskonsolidierung unterliegen, sind allerdings noch weitgehend unbekannt.
Um die Beteiligung an Lernprozessen von PSA im Vergleich zur extrazellularen Domäne des NCAM-Glycoprotein-Rückgrats zu untersuchen, wurden NCAM, PSA-NCAM oder PSA in den dorsalen Bereich des Hippocampus’ von Wildtyp-Mäusen während verschiedener Phasen der auditorischen Furcht-Konditionierung injiziert. Als interne Kontrolle dafür, dass die Injektionen in den Hippocampus keine unspezifische Wirkung auf Hippocampus-unabhängige Formen von Lernen haben, wurde ein Paradigma für die Furcht-Konditionierung gewählt, in dem die Tiere gleichzeitig Hippocampus-unabhängigem Lernen eines Tons und Hippocampus-abhängigem Lernen eines Kontextes unterworfen waren. Injektion von PSA, allein oder an NCAM gebunden, vor dem Training verminderte die Bildung von Hippocampus-abhängigem Kontext-Gedächtnis, was anhand der Erstarrungsreaktion als Furchtantwort bestimmt wurde. Injektion von NCAM allein hatte keine Wirkung. Die Verfestigung des Kontext-Gedächtnisses wurde nur durch PSA-NCAM beeinträchtigt, wenn das Molekül während der späten Phasen der Konsolidierung injiziert wurde. Eine Injektion in frühen Phasen zeigte keinen Effekt. Keine der getesteten Substanzen hatte eine Auswirkung auf extra-hippocampales Hinweisreiz-gelenktes Gedächtnis. Mäuse, denen die Polysialyltransferase (ST8SialV/PST), die für die Anlagerung von PSA an NCAM im erwachsenen Tier verantwortlich ist, fehlt, zeigten nur ein leichtes Defizit im Hippocampus-abhängigen Kontext-Lernen. Im Vergleich waren NCAM-defiziente Mäuse sowohl im Kontext-Gedächtnis also auch in der Hinweisreiz-gelenkten Erinnerung beeinträchtigt. Die Fähigkeit zur Bildung von Kontext-Gedächtnis in NCAM-defizienten Mäusen konnte durch die Injektion von PSA-NCAM in den Hippocampus vor dem Training wiederhergestellt werden. Dies verdeutlicht, dass die Beteiligung von PSA-NCAM an Lernprozessen nicht auf der Modulation von NCAM-NCAM homophilen Interaktionen beruht, sondern eher durch seine heterophilen Inderaktionspartner erfolgt. Diese in vivo Ergebnisse wurden von in vitro Daten unterstützt, die inhibitorische Effekte von PSA auf die Langzeitpotenzierung (LTP) in der CA1-Region des Hippocampus’ in Wildtyp-Mäusen zeigten. Außerdem hatte PSA positive Effekte auf die gestörte Langzeitpotenzierung in der CA1-Region von Hippocampus-Schnitten NCAM-defizienter Mäuse. Zusammenfassend unterstützen die Ergebnisse dieser Arbeit die Ansicht, dass PSA-NCAM sowohl an der Bildung als auch an der späten Phase der Konsolidierung des Kontext-Gedächtnisses beteiligt ist und synaptische Plastizität verstärkt.
Unter Verwendung des Tamoxifen-induzierbaren LoxP-Systems, das eine zeitlich kontrollierte Zerstörung des NCAM-Gens im Gehirn erwachsener Mäuse erlaubt, konnte gezeigt werden, dass NCAM notwendig ist für die Bildung und/oder die Aufrechterhaltung von Hippocampus-abhängigem Kontext-Gedächtnis. Währenddessen ist Amygdala-bedingte Hinweisreiz-gelenkte Erinnerung weniger abhängig von der induzierten Zerstörung von NCAM. Diese Ergebnisse sind interessant, da das konstitutive pränatale Fehlen von NCAM sowohl Hippocampus- als auch Amygdala-abhängige Defizite in der Furcht-Konditionierung mit sich bringt, und damit die Frage entsteht, ob NCAM für die Entwicklung der Amygdala notwendig ist. Eine andere mögliche Erklärung wäre, dass nach induzierter Zerstörung von NCAM die Konzentration des intakten Moleküls in der Amygdala ausreichend bleibt, um ihre Funktionen zu gewährleisten.
Faszinierend ist, dass die Verstärkung der Aktivität von NMDA-Glutamatrezeptoren mit Hilfe von D-Cycloserin, einem Agonisten der Glycin-Bindedomäne dieser Rezeptoren, schwere kognitive Defizite im Bereich von Lernen und Gedächtnis bezüglich Kontext und Hinweisreiz-gelenkter Informationen in NCAM-defizienten Mäusen ausgleichen konnte. Diese Ergebnisse decken sich mit ersten Daten aus im Moment durchgeführten in vitro Studien, die zeigen, dass in Hippocampus-Schnitten von NCAM- oder PSA-defizienten Mäusen LTP in der CA1-Region mit Hilfe von D-Cycloserin wiederhergestellt werden kann. Daher nehmen wir an, dass der Verlust von NCAM und/oder PSA zu einer beeinträchtigten Funktion der NMDA-Rezeptoren während der Induktion synaptischer Plastizität und Furcht-Konditionierung führt. Da zur Wiederherstellung des Hippocampus-abhängigen Kontext-Gedächtnisses geringere Konzentrationen von D-Cycloserin ausreichten als für die Wiederherstellung der Amygdala-abhängigen Hinweisreiz-bedingten Erinnerung notwendig waren, lässt sich auf Unterschiede in der Regulation von NMDA-Rezeptoren durch PSA-NCAM in Hippocampus und Amygdala schließen. Die Bedeutung dieser Ergebnisse wird betont durch Studien, die eine genetische Verbindung zwischen Schizophrenie und Mutationen der Polysialyltransferase ST8SialI/STX offenbarten sowie ein Defizit in der Produktion von PSA und eine Überproduktion von löslichem NCAM in Gehirnen, die Schizophrenie aufweisen, zeigten
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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