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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
Untersuchungen zu Form und Funktionder Leuchtorgane des Nordischen Krill Meganyctiphanes norvegica (M. SARS, 1857)(Crustacea: Euphausiacea)
No full textIn der vorliegenden Arbeit wurden Fragestellungen aus verschiedenen Themenkomplexen bearbeitet, die dazu beitragen sollen, ein Verständnis für die Bedeutung der Leuchtorgane im Lebenszyklus des Nordischen Krill, Meganyctiphanes norvegica (M.Sars), zu entwickeln.
In einem morphologisch-histologischen Teil wurden die thorakalen und abdominalen Leuchtorgane und ihr peripheres Umfeld, zum ersten Mal mittels Rasterelektronenmikroskopie (REM) und dreidimensionaler Rekonstruktionen (3D-Modelle) aus Semidünnschnittserien untersucht. Für die thorakalen Leuchtorgane zeigen die Ergebnisse, dass die Rotation der Leuchtorgane durch zwei antagonistisch wirkende Muskeln bewirkt wird, welche nur auf einer Seite inserieren und mit einem sehnenartigen Ligament verwoben sind. Für das Abdomen bestätigen die Aufnahmen die klassischen Beschreibung, dass alle vier Leuchtorgane synchron durch ein durch die fünf ersten Abdominalsegmente verlaufendes Ligamentsystem bewegt werden. Ergänzt wurde dieser Teil durch Immunfluoreszenzfärbungen an den Leuchtorganen der Augenstiele, des Thorax und des Abdomens. Die verwendeten Antikörper gegen Serotonin, Serotoninrezeptor 5- HT1crust, methyliertes -Tubulin, Octopamin, Synapsin, Na-K-ATPase sowie rhodamingekoppeltes Phalloidin lieferten alle detektierbare und lokalisierbare Signale. 5-HT und Octopamin bilden Netzwerke von Axonkollateralen, welche nicht vom Antikörper gegen Tubulin markiert werden. Der Serotoninrezeptor ist auf den Zellen, die den Streifenkörper (die "Laterne") bilden, lokalisiert. Synapsin und Na-K-ATPase sind in den gleichen Regionen lokalisiert bzw. konzentriert wie die Endigungen der Blutkapillaren. Auf diesen Beobachtungen basierend wird ein modifiziertes Modell der Leuchtsteuerung nach Krönström et al. (2009) postuliert. In einem pharmakologischen Teil wurde die Auslösung der Biolumineszenz durch Badapplikation von Serotonin sowie die Injektion von Serotonin in die Hämolymphe untersucht. Die Auslösung des Leuchtens bzw. die Wechselwirkung mit dem Serotonineffekt wurde für verschiedenen Substanzen getestet. 8-OH-DPAT, 5-Methoxytryptamin, Forskolin und Calcimycin lösen bei Injektion in die Hämolymphe das Leuchten aus. Octopamin, Pimozide, Propanolol und Tyramin haben bei gleichzeitiger Applikation mit Serotonin keinen signifikanten Einfluss auf Leuchtdauer oder Latenz, hingegen reduzieren Fluoxetin und Methiothepin die Leuchtdauer. In einem weiteren Teil wurde die spontane Biolumineszenz im Gullmarfjord (Schweden) mittels Sonden, die über Lichtvervielfacherröhren verfügten, untersucht. Insgesamt wurde 602 Stunden lang in verschiedenen Tiefen die wohl größtenteils unstimulierte Biolumineszenz aufgezeichnet und ungefähr 73000 Lichtsignale registriert. Diese wurden nach Form kategorisiert und nach zeitlichem Abstand zueinander analysiert, wobei keine wiederkehrenden Muster gefunden wurden. Im Labor beobachteter Krill zeigte keine spontane Biolumineszenz, weswegen keine Aussage über die Beteiligung des Krill an der im Freiwasser vorkommenden Biolumineszenz gemacht werden kann. Mittels eines dreidimensionalen Kamerasystems wurden Schwimmtrajektorien des Krill im Labortank gefilmt und ausgewertet mit Hinblick auf die gezeigten Verhaltensweisen. Mittels zwei unterschiedlicher Geräte mit Rotationsscheiben, welche eine serielle Messung (>100 Hz) der Umgebungshelligkeit und der Biolumineszenz des Krill ermöglichen, wurde die Hypothese der Gegenlichtillumination ("countershading") untersucht, welche aber nicht bestätigt wurde.In the presented work different experiments from different fields of research have been performed to contribute to an understanding of the role of light organs in the life history of the Nordic Krill, Meganyctiphanes norvegica (M.Sars). In a morphological-histological part the light organs (and the accompanying structures) of the eye stalks, the thorax and the abdomen have been studied for the first time by means of scanning electron microscopy as well as by preparation of 3D models based on three dimensional reconstructions from serial sectioning series. The rotation of the thoracic light organs is facilitated by two antagonistically
working muscles, attached to one side of the light organ; they are wrapped by a ligament system, probably for force storage similar to a tension spring. The results for the abdominal light organs confirm
the classic descriptions: all four light organs are rotated synchronically by a single ligament system running through the first five abdominal segments. This part is complemented by immunohistochemistry of the light organs of the eye stalks, the thoracic and abdominal segments. Rhodamine conjugated phalloidin, as well as antibodies directed against serotonin (5-HT), serotonin receptor 5-HT1crust, methylated alpha-tubuline, octopamine, synapsin, and Na-K-ATPase, showed detectable and localizable signals. Phalloidin labeled the capillaries. Structures showing 5-HT- and octopamine-immunoreactivity are forming networks of probably axon collaterals within the light organs, which are not labelled by the tubuline antibody. The serotonin receptor is located on the cells forming the striated body (the “lantern”). Synapsine and Na-K-ATPase are localized within the vicinity of capillary endings, thought to have sphincter functions. Incorporating these findings, a modified version of the model for the control of light production proposed by Krönström et al. (2009) is presented. In a pharmacological work the influence of bath applicated and injected 5-HT on latency and duration of light production was examined. The triggering of the bioluminescence or the interaction with serotonin was examined for different pharmacological agents known to influence serotonergic systems. 8-OH-DPAT, 5-methoxytryptamin, forskolin, and calcimycin trigger light production when injected into the hemolymph. Octopamine, pimozide, propanolol, and tyramine did not have a significant influence on latency or duration onto bioluminescence elicited by serotonin, whereas fluoxetin and methiothepin reduced the duration. The spontaneous bioluminescence in the free waters of Gullmarfjord, Sweden, in different depth at different times of the year, was recorded by underwater probes equipped with photomultiplier tubes. A total of 602 hours of continuous recordings of probably mostly nonstimulated bioluminescence showed about 73000 light signals. These were classified into different flash categories, then analyzed by the time spacing in between two consecutive flashes, but no recurring patterns were found. Krill observed in water tanks in the lab did not show spontaneous flashing behaviour; therefore no statement can be made concerning the involvement of krill in naturally occurring bioluminescence in the deep waters of the fjord. The swimming behaviour of the krill was recorded and categorized in the lab with a dual camera system recording three-dimensional trajectories. With two different versions of recording hardware, equipped with spinning discs for serial measurement (>100 Hz) of the stimulus light intensity and the bioluminescence of the krill, the hypothesis of countershading was examined, but could not be confirmed in this setup
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
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