1,720,983 research outputs found
Length and width measurements of Fragilariopsis kerguelensis valves from sediment core PS1768-8
No full textLight microscopy analysis of diatom frustules is widely used in basic and applied research, notably taxonomy, morphometrics, water quality monitoring and paleo-environmental studies. Although there is a need for automation in these applications, various developments in image processing and analysis methodology supporting these tasks have not become widespread in diatom-based analyses. We have addressed this issue by combining our automated diatom image analysis software SHERPA with a commercial slide-scanning microscope. The resulting workflow enables mass-analyses of a broad range of morphometric features from individual frustules mounted on permanent slides. Extensive automation and internal quality control of the results helps to minimize user intervention, but care was taken to allow the user to stay in control of the most critical steps (exact segmentation of valve outlines and selection of objects of interest) using interactive functions for reviewing and revising results. In this contribution, we describe our workflow and give an overview of factors critical for success, ranging from preparation and mounting through slide scanning and autofocus finding to final morphometric data extraction.
To demonstrate the usability of our methods we finally provide an example application by analysing Fragilariopsis kerguelensis valves originating from a sediment core, which substantially extends the size range reported in the literature
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
Optimierung der Auswertmethodik zur Quantifizierung von pathologischen Veränderungen durch Carbon Nanotubes
No full textCarbon nanotubes (CNTs) sind Kohlenstoffverbindungen, die sich aus einem oder mehreren Zylindern einer aufgerollten Graphitschicht zusammensetzen. Zu ihren einzigartigen Eigen-schaften zählen eine hohe Zugfestigkeit, elektrische Leitfähigkeit sowie chemische Inertheit, weshalb sie in Leichtbau, Halbleitertechnik und Medizin gleichermaßen begehrt sind. Ihre dem mineralischen Asbest sehr ähnliche Struktur wirft jedoch Fragen über mögliche Gesund-heitsrisiken durch die Inhalation der Fasern bei ihrer Verarbeitung auf. In der Studie "Chronic Study after intraperitoneal Injection of Carbon Nanotube Samples in Rats" (Zeitraum November 2011 - Januar 2013) untersuchte das Fraunhofer ITEM die Toxizität intra-peritoneal injizierter Karbonnanoröhrchen unterschiedlicher Produktionsart anhand der Zell-proliferation im Mesothel der Peritonealorgane von Wistar-Ratten. Die Untersuchung wurde an formalinfixiertem und in Paraffin eingebettetem Gewebe von Zwerchfell und Milz nach immunhistochemischer Behandlung mit einem Zellteilungsmarker (Bromdesoxyuridin, BrdU) durchgeführt. Zur Bestimmung der Zellzahlen wurden zwei weitestgehend automatisierte, computergestützte Methoden mit unterschiedlichen Ansätzen entwickelt: Eine wurde für die Fluoreszenz-, die andere für die Hellfeldmikroskopie konzipiert. In einem direkten Vergleich wurde ermittelt, dass beide Methoden mit geringen Einschränkungen für die Proliferations-analyse geeignet waren. Durch die Bestimmung des LI nach einer Versuchsdauer von 3 Monaten wurden in 2 von 3 Gruppen Signifikanzen ermittelt, deren Tiere später Meso-theliome aufwiesen. Die frühzeitige Erkennung der Toxizität von Kohlenstoffnanoröhrchen war folglich bis zu einem gewissen Grad möglich. Durch die Ermittlung des Makrophagenanteils an der Gesamtzellzahl von durchschnittlich 5% und einer gleich bleibenden Proliferationsrate konnte angenommen werden, dass ihre Berücksichtigung zur Bestimmung der Zellproliferation im Mesothel nicht zwingend erforderlich war. Ihr konkreter Einfluss auf die Bildung von Mesotheliomen müsste aber noch in unabhängigen Studien untersucht werden.Carbon nanotubes (CNTs) are carbon compounds consisting of one or several cylindrical wrapped graphene layers. Their tensile strength, potential of electric conduction as well as chemical inertness, makes them unique materials in lightweight construction, semi-conductor engineering and medicine. However, their structure resembles the one of mineral asbestos. This suggests similar toxic effects and health risks after inhalation during their processing, as it had been proven for asbestos. In the study "Chronic Study after intraperitoneal Injection of Carbon Nanotube Samples in Rats" (time span from November 2011 - January 2013) different types of intraperitoneal injected carbon nanotubes were tested by the Fraunhofer ITEM upon toxicity based on cell proliferation analysis in the mesothel of the peritoneal organs of Wistar rats. The tests were accomplished on formalin fixed and paraffin embedded tissue from diaphragm and spleen after immunohistochemical preparation with a cell proliferation marker (bromodeoxyuridine, BrdU). The aim was to evaluate the number of cells for the most part with automatic methods; therefore two slightly different computer based methods were developed: The first one was used for fluorescence microscopy the second one for bright-field microscopy. When comparing the two methods it turned out that both were suitable for cell proliferation analysis with only small limitations. Analysis results revealed that after a test period of 3 months significant differences in the determined labeling index (LI) were present in 2 of 3 groups, whose animals showed mesothelioma later on. These methods could therefore help to detect toxic effects of CNTs at an early stage up to a certain degree. Furthermore, the additionally evaluated average percentage of macrophages (measured against the total number of cells) and their proliferation rate did not show significant differences between treated and control groups. Therefore, it can be assumed that the consideration of macrophages is not mandatory for the determination of the mesothelial proliferation. Nevertheless, further studies are needed to clarify their specific influence on the induction of mesothelioma
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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