1,721,001 research outputs found
Report of the Working Group on Harp and Hooded Seals (WGHARP) [15 - 19 August 2011 St. Andrews, Scotland, UK]
Get PDFContributors: Anne Kirstine Frie, Tore Haug, Tor Arne Øigård
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
Inner membrane proteins YgdD and SbmA are required for the complete susceptibility of escherichia coli to the proline-rich antimicrobial peptide arasin 1(1–25)
No full textArasin 1 from the spider crab Hyas araneus is a proline-rich antimicrobial peptide (PR-AMP), which kills target bacteria by a non-membranolytic mechanism. By using a fluorescent derivative of the peptide, we showed that arasin 1 rapidly penetrates into Escherichia coli cells without membrane damage. To unravel its mode of action, a knockout gene library of E. coli was screened and two types of mutants with a less susceptible phenotype to the arasin 1 fragment (1–23) were found. The first bore the mutation of sbmA, a gene coding for an inner membrane protein involved in the uptake of different antibiotic peptides. The second mutation was located in the ygdD gene, coding for a conserved inner membrane protein of
unknown function. Functional studies showed that YgdD is required for the full susceptibility to arasin 1(1–25), possibly by supporting its uptake and/or intracellular action. These results indicated that different bacterial proteins are exploited by arasin 1(1–25) to exert its antibacterial activity and add new insights on the complex mode of action of PR-AMP
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
Antimicrobial natural products from Arctic and sub-Arcticmarine invertebrates
Get PDFInfectious diseases are a leading cause of death world-wide and there is a growing need for new anti-infective agents to combat multi-resistant strains of bacteria and fungi. Marine natural products are promising sources of novel antimicrobial compounds. In the present thesis, an investigation into the antimicrobial metabolites of Arctic and sub-Arctic marine invertebrate species is presented. Extracts of seven ascidian species, six sponge species, a soft-alcyonid coral and a bryozoan species, were screened for their antimicrobial activities. The extracts were pre-fractionated by solid phase extraction (SPE) and purified by reversephase high-performance liquid chromatography (RP-HPLC). Active metabolites were characterized by electrospray ionization mass spectrometry (ESI-MS) and nuclear magnetic resonance (NMR) techniques.
The antibacterial tyrosine-derived guanidines, 3-dihydroxy-tubastrine and tubastrine, have been isolated from the ascidian Dendrodoa aggregata. This is the first report on the isolation of active metabolites from D. aggregata. 3-dihydroxy-tubastrine has previously been isolated
from the Australian sponge species Spongosorites sp. The compound was present in high concentrations in extracts of the ascidian and could serve as a chemotaxonomic marker for the species.
Extracts of the ascidian Synoicum pulmonaria displayed the highest antimicrobial activities in our assays. Bio-guided fractionation of the extract, revealed the presence of three novel compounds, named synoxazolidinones A, B and C. The structures of the compounds were
elucidated by spectroscopic methods including 1D and 2D NMR techniques, and analysis of mass spectrometric data. The absolute configuration of the compounds was also established by computational methods. The synoxazolidinones contain a unique 4-oxazolidinone core rarely encountered in natural products. Biogenetically, the compounds appear to be derived from arginine and tyrosine. This is the first report on the chemistry of S. pulmonaria.
Synoxazolidinones also displayed anticancer activities and provide novel chemical scaffolds for structure-activity relationship studies which are currently being carried out.
The dibrominated tryptophan-derived metabolite, eusynstyelamide B, and three new
derivatives, eusynstyelamides D, E and F, have been isolated from the bryozoan Tegella cf. spitzbergensis. The structures of the compounds were elucidated by mass spectrometry and, 1D and 2D NMR techniques. All four compounds displayed potent antibacterial activities in our assays. This is the first report of bioactive metabolites from T. spitzbergensis. Eusynstyelamide B has previously been isolated from the Australian ascidian Eusynstyela latericius. The presence of the same metabolites in different organisms and environments,
suggests biosynthesis by symbiotic microorganisms.
In addition, this thesis provides background information on natural product research and current antimicrobial investigations of marine invertebrate species. The potential of Arctic and sub-Arctic marine invertebrates as sources of structurally novel, bioactive metabolites is demonstrated
Antimikrobielle forbindelser i sjøstjernen Asterias rubens og sjøpølsen Cucumaria frondosa.
Get PDFDet er en økende bekymring for at antibiotikaene vi har tilgjengelige i dag ikke vil være effektive mot humane patogener grunnet resistensutvikling. WHO har uttalt at en pre-antibiotika tid der vanlige infeksjoner og mindre skader kan drepe, er en reell virkelighet i det 21. århundre. Havet dekker over 70% av jordoverflaten, og det er estimert at mellom 50 og 80% av alle arter lever i havet. Organismer som lever i havet er konstant utsatt for høye konsentrasjoner av bakterier og virus, slik at organismer som lever der trenger et velfungerende immunsystem. Pigghuder er for det meste bentiske organismer, som ikke viser den samme adaptive immunresponsen som vertebrater. De derfor avhengig av å produsere antimikrobielle forbindelser for å forhindre angrep fra patogener, og er derfor et interessant mål for å finne nye antitiotik
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