1,720,995 research outputs found
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
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
A Blocking Group Scan Using a Spherical Organometallic Complex Identifies an Unprecedented Binding Mode with Potent Activity In Vitro and In Vivo for the Opioid Peptide Dermorphin
No full textHerein, the selective enforcement of one particular receptor-ligand interaction between specific domains of the μ-selective opioid peptide dermorphin and the μ opioid receptor is presented. For this, a blocking group scan is described which exploits the steric demand of a bis(quinolinylmethyl)amine rhenium(I) tricarbonyl complex conjugated to a number of different, strategically chosen positions of dermorphin. The prepared peptide conjugates lead to the discovery of two different binding modes: An expected N-terminal binding mode corresponds to the established view of opioid peptide binding, whereas an unexpected C-terminal binding mode is newly discovered. Surprisingly, both binding modes provide high affinity and agonistic activity at the μ opioid receptor in vitro. Furthermore, the unprecedented C-terminal binding mode shows potent dose-dependent antinociception in vivo. Finally, in silico docking studies support receptor activation by both dermorphin binding modes and suggest a biological relevance for dermorphin itself. Relevant ligand-protein interactions are similar for both binding modes, which is in line with previous protein mutation studies
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
Structural and phylogenetical analysis of the archaeal parvulin NmPin from Nitrosopumilus maritimus
No full textDer cis/trans-Übergang von Xaa-Pro-Peptidbindungen benötigt bei moderaten Temperaturen einer Katalyse. Die Proteine, welche für diese Katalyse zuständig sind, die Peptidyl-Prolyl-cis/trans-Isomerasen (PPIasen) werden in drei sich in Primärsequenz, Sekundärstruktur und Funktionsweise unterscheidende Proteinfamilien eingeteilt. Zwei dieser Familien werden aufgrund ihrer Interaktion mit Immunsuppressiva als Immunophiline bezeichnet; die Cyclophiline binden Cyclosporin A, die FKBP (FK506 Bindeproteine) Tacrolimus.
Diese Arbeit beschäftigt sich mit der dritten PPIase-Familie, den Parvulinen. Der bestuntersuchte Vertreter dieser Familie hPin1 ist sowohl beteiligt an der Ausbildung neurodegenerativer Erkrankungen, wie Morbus Alzheimer und Morbus Parkinson, als auch am Alterungsprozess und der Entstehung zahlreicher Tumorarten. Trotz einer Vielzahl struktureller Studien, an Parvulinen aus Eukarya, Bacteria und Fungi, blieb der Mechanismus der Peptidyl-Prolyl-cis/trans-Isomerisierung durch die Parvuline ungeklärt. Im letzten Jahrzehnt stieg die Zahl gelöster archaealer Genome sprunghaft an und einige dieser Genome trugen auch Parvuline des Par10-Typ (single domain Parvulin). Um einen Beitrag zur Auflösung des Isomerisierungsmechanismus der PPIC-Typ-PPIasen zu leisten wurde das Parvulin des einzigen kultivierbaren Archaeen welcher ein Parvulingen codiert, Nitrosopumilus maritimus, für diese Arbeit gewählt.
Es konnte gezeigt werden, dass die archaealen und bakteriellen sdPar, sowohl durch phylogenetische Ansätze, als auch durch Experimente maschinellen Lernens voneinander unterschieden werden können. Des Weiteren wurde klar, dass die archaealen Parvuline ein echtes, „urtümliches“ Phylum darstellen und nicht etwa durch horizontalen Gentransfer aus Bacteria entstanden sind. Die verwendete Maximum Likelihood-Phylogenie lieferte in Kombination mit dem genetischen Hintergrund des archaealen Parvulingens sehr brauchbare evolutionäre Information. Die Datenbankanalysen ergaben zudem eine Korrelation zwischen hohen Lebensraumtemperaturen und geringen PPIase-Repertoire.
Die NMR-Struktur von NmPin, mit einer Auflösung über alle Atome von 0,80 Å, wies das typische β3αβα2β-Parvulinfaltungsmuster, sowie ein, in früheren Studien bereits für Par14 und PrsA gezeigtes, Ladungsnetzwerk im aktiven Zentrum auf. Untersuchungen des elektrostatischen Potentials zeigten, das NmPin über eine positive geladene Interaktionsfläche verfügt, in deren Mitte ein reduziertes Cystein sitzt. Diese Beobachtung, sowie die Vorhersage eine möglichen Palmitylierung dieses Cysteins und immunobiochemische Experimente mit N. maritimus-Lysat, wiesen darauf hin, dass NmPin ein Membranprotein sein könnte.Cis/trans-isomerisation of Xaa-Pro-bonds depends on catalysis. The proteins responsible for this catalysis, the peptidyl-prolyl-cis/trans-isomerases (PPIases), are separated in three protein families, which differ in primary sequence, secondary structure and functionality. Two of these families are grouped as immunophilins because of their interaction with immunosuppressants; cyclophilins bind cyclosporin A, FKBPs (FK506 binding proteins) bind tacrolimus.
This work deals with the third family of PPIases, the parvulins. The most studied parvulin, Pin1, is involved in the development of neurodegenerating diseases like Morbus Alzheimer and Morbus Parkinson as well as in aging and the development of many kinds of tumors. Despite numerous structural studies with parvulins from Eukarya, Bacteria and Fungi the mechanism of peptidyl-prolyl-cis/trans-isomerisation remained unsettled. During the last decade the number of solved archaeal genomes jumped up and some of these new genomes included Par10-type parvulins (single domain parvulins). To contribute in the elucidation of PPIC-type-PPIases isomerisation mechanism, the parvulin out of the only cultivatable Archaea including one, Nitrosopumilus maritimus, has been chosen for this work.
The possibility to separate archaeal from bacterial sdPars by using phylogenetics as well as machine learning approaches has been shown. Furthermore the evolution of archaeal parvulins through events of horizontal gene transfer could be excluded. The applied maximum likelihood phylogeny combined with genetic background analysis of the archaeal parvulin gene delivered satisfying information. Searching data bases led to a correlation between high living temperatures and small PPIase repertoires.
NmPin’s NMR structure, exhibiting a 0.80 Å resolution over all atoms, showed the parvulin typical β3αβα2β-fold as well as a charge relay system in the catalytic centre that Par14 and PrsA showed in former studies. Examining the electrostatic potential of NmPin’s surface illustrated a positively charged interface bearing a central reduced cysteine. This fact as well as the prediction of a potential palmitoylation of this cysteine and immunobiochemical approaches with N. maritimus lysate gave evidence for NmPin to be a membrane associated protein
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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