1,720,970 research outputs found
Life Cycle Thinking principles for the design of sustainable seismic retrofit interventions
No full text
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
Catalytic Activity, Stability, Unfolding, and Degradation Pathways of Engineered and Reconstituted Myoglobins
No full textThe structural and functional consequences of
engineering a positively charged Lys residue and
replacing the natural heme with a heme-L-His derivative
in the active site of sperm whale myoglobin (Mb) have
been investigated. The main structural change caused by
the distal T67K mutation appears to be mobilization of
the propionate-7 group. Reconstitution of wild-type and
T67K Mb with heme-L-His relaxes the protein fragment
around the heme because it involves the loss of the
interaction of one of the propionate groups which stabilize
heme binding to the protein. This modification
increases the accessibility of exogenous ligands or substrates
to the active site. The catalytic activity of the
reconstituted proteins in peroxidase-type reactions is
thus significantly increased, particularly with T67K Mb.
The T67K mutation slightly reduces the thermodynamic
stability and the chemical stability of Mb during catalysis,
but somewhat more marked effects are observed by
cofactor reconstitution. Hydrogen peroxide, in fact, induces
pseudo-peroxidase activity but also promotes
oxidative damage of the protein. The mechanism of
protein degradation involves two pathways, which depend
on the evolution of radical species generated on
protein residues by the Mb active species and on the
reactivity of phenoxy radicals produced during turnover.
Both protein oligomers and heme-protein cross-links
have been detected upon inactivation
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
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