1,721,005 research outputs found
Structure of the archaeal chemotaxis protein CheY in a domain-swapped dimeric conformation
Get PDFArchaea are motile by the rotation of the archaellum. The archaellum switches between clockwise and counterclockwise rotation, and movement along a chemical gradient is possible by modulation of the switching frequency. This modulation involves the response regulator CheY and the archaellum adaptor protein CheF. In this study, two new crystal forms and protein structures of CheY are reported. In both crystal forms, CheY is arranged in a domain-swapped conformation. CheF, the protein bridging the chemotaxis signal transduction system and the motility apparatus, was recombinantly expressed, purified and subjected to X-ray data collection
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
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
Strukturelle Untersuchungen von Blutgerinnungsfaktor XIII
Get PDFFaktor XIII ist eine Transglutaminase, die Fibrinmoleküle quervernetzen kann. Die Struktur der inaktiven Form ist bekannt und die Biochemie der Aktivierung ebenso. Die vorliegende Arbeit beschäftigt sich mit dem Versuch der Strukturbestimmung der aktiven Form. Dies umfasst Experimente zur Expression, Aktivierung, Aufreinigung und Kristallisation. Des Weiteren wurde durch den Vergleich verschiedener Kristallstrukturen der inaktiven Form die Domänenbeweglichkeit analysiert, um die strukturellen Veränderungen bei der Aktivierung zu postulieren
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
Charakterisierung zytosolischer 5'-Nukleotidasen aus Mensch und Drosophila melanogaster
Get PDFInnerhalb dieser Arbeit wurden zytosolische 5'-Nukleotidasen untersucht, Enzyme des Nukleotidstoffwechsels. Diese Enzyme katalysieren die Dephosphorylierung von 5'-Nukleosidmonophosphaten. Im Fokus stand die Charakterisierung einer erst kürzlich entdeckten 5'-Nukleotidase (DmcN3B) aus D. melanogaster, die neben Pyrimidinnukleotiden auch ein modifiziertes 5'-NMP als Substrat umsetzte, nämlich m7GMP. Auch die humanen Homologen cN3A und cN3B wurden charakterisiert und es wurde festgestellt, dass beide humanen Enzyme auch m7GMP umsetzen können. Zur Klärung dieses Sachverhaltes wurde die Struktur der DmcN3B mit Produkten der Reaktion gelöst. Durch diese Strukturen konnte gezeigt werden, warum die DmcN3B sowohl Pyrimidine als auch m7GMP umsetzen kann. Die physiologische Funktion dieses Enzyms wurde durch knockout-Studien in D. melanogaster untersucht. Dabei wurde ein embryonaler Arrestphänotyp festgestellt, der eine regulative Funktion der 5'-Nukleotidase im Nukleotidstoffwechsel nahelegt.In this work cytosolic 5' Nucleotidases haven been studied, enzymes of the nucleotide metabolism. Those enzymes catalyze the dephosphorylation of 5' nucleoside monophosphates. In the focus was the characterisation of a newly discovered 5' Nucleotidase (DmcN3B) from D. melanogaster which can dephosphorylate next to pyrimidine nucleotides also the modified nucleotide m7GMP. The human homologs cN3A and cN3B have also been studied and it was shown that both of them were able to accept m7GMP as a substrate. To clarify the substrate specificity the structure of DmcN3B together with different products of the reaction has been solved. Thereby it could be shown why the DmcN3B can accept pyrimidine as well as a purine nucleotide as a substrate. The physiological function of this enzyme was investigated by knockout studies in D. melanogaster. An embryonic arrest phenotype and broader disturbances in the nucleotide pool suggest a regulatory function of the DmcN3B in the nucleotide metabolism.vorgelegt von Juliane Buschman
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
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