1,720,968 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
Identification of aldehyde oxidizing enzymes in P. taiwanensis VLB120 and generation of a tolerance-optimized chassis strain
No full textUnveiling Pseudomonas’ enzymatic toolbox for 5‑(hydroxymethyl)furfural (HMF) detoxification
No full textToleranz-Engineering von Pseudomonas für die effiziente Umwandlung und Produktion von Aldehyden
No full textDispelling 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
Tolerance engineering of Pseudomonas for the efficient conversion and production of aldehydes
No full textBiocatalysis holds promise to tackle the sustainability challenges faced by chemical industry due to climate change and depletion of fossil resources. However, obstacles emerge regarding the compatibility of several important chemicals, notably aldehydes, with biological systems, even if remarkably robust workhorses such as bacteria of the Pseudomonas clade are employed. This is related to the high and versatile reactivity of aldehydes, which is both their greatest asset and the root cause of their toxicity. Competitive biocatalytic processes involving these substances thus require tolerance-improved host organisms. In view of the constantly growing demand for renewable and ecologically produced plastics, the biocatalytic oxidation of the burgeoning platform chemical 5-(hydroxymethyl)furfural (HMF) to 2,5-furandicarboxylic acid (FDCA) is of particular interest since FDCA can substitute structurally similar and fossilbased terephthalic acid in polyesters. With the periplasmic oxidoreductase complex PaoEFG and the cytoplasmic dehydrogenases AldB-I and AldB-II, the primary enzymes responsible for the oxidation of HMF and further aromatic aldehydes like 4-hydroxybenzaldehyde and vanillin by P. taiwanensis VLB120 and P. putida KT2440 were uncovered. This marks a significant advancement from former black-box application of these strains to specialized biocatalysts with fine-tuned properties. To illustrate, overexpression of the newly characterized genes resulted in so-called BOX-strains (Boosted OXidation) with up to tenfold increased initial oxidation rates in comparison to the wild type. As a result, the new variants exhibited increased robustness when growing in presence of HMF and also proved to be more efficient for the complete oxidation of the aldehyde to the industrial target compound FDCA. Furthermore, tolerance mechanisms distinct from rapid oxidation were sought applying an adaptive laboratory evolution approach. A ROX (Reduced OXidation) deletion mutant with diminished aldehyde conversion ability was subjected to steady HMF stress. This yielded toleranceimproved strains through the unforeseen inactivation of the regulator MexT and the associated shutdown of the efflux pump MexEF-OprN. Another potential use for oxidation-deficient, yet solvent-tolerant, Pseudomonads is the biosynthesis of aromatic aldehydes, as showcased with the popular aroma compound t-cinnamaldehyde. In conclusion, this thesis contributes to the fundamental understanding of aromatic aldehyde conversion by P. taiwanensis VLB120 and P. putida KT2440 by unveiling the underlying enzymes which were shown to constitute the organisms’ main tolerance mechanism against these toxic substances. Their overexpression in BOX strains strongly increases aldehyde tolerance, and enables improved FDCA production by boosted HMF oxidation. Reduced aldehyde oxidation and reduction (ROAR) unlocks P. taiwanensis VLB120 for the (de novo) production of valuable aromatic aldehydes or aldehyde-derived products, thereby expanding the product portfolio of this aspiring microbial cell factory
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