1,721,010 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
Alteration of apparent negative cooperativity of ATPase activity by alpha-subunit glutamine 173 mutation in yeast mitochondrial F1. Correlation with impaired nucleotide interaction at a regulatory site.
No full textInternational audienceThe first described alpha-subunit mutation of yeast mitochondrial F1 has been recently identified as a single Gln173----Leu substitution in a strongly conserved sequence (Falson, P., Maffey, L., Conrath, K., and Boutry, M. (1991) J. Biol. Chem. 266, 287-293). This mutation is shown here to greatly modify the biphasic pattern of ATPase activity as a function of pH: (i) the shoulder observed at acidic pH is significantly increased; (ii) the main peak, at alkaline pH, is markedly lowered; (iii) the optimal pH is shifted from 8.8 to 7.7. The mutation lowers both apparent negative cooperativity and sensitivity to azide inhibition which concomitantly increase when the assay pH decreases. Azide partial inhibition produces apparent negative cooperativity which can be further abolished by bicarbonate. The mutation increases both activation energies determined from biphasic Arrhenius plots. The mutation decreases the inactivation rate by 5'-p-fluorosulfonylbenzoyladenosine and abolishes the protection by nucleotide binding at the adenine-specific regulatory site. On the contrary, it does not modify the reactivity of 5'-p-fluorosulfonylbenzoylguanosine at the less-selective catalytic site. In addition, partial inactivation by 5'-p-fluorosulfonylbenzoyladenosine, as opposed to 5'-p-fluorosulfonylbenzoylguanosine, produces apparent negative cooperativity under conditions where unmodified-enzyme kinetics are noncooperative. The results show that alpha-Gln173 participates in nucleotide interaction at a regulatory site which controls the negative cooperativity of F1-ATPase activity.The first described alpha-subunit mutation of yeast mitochondrial F1 has been recently identified as a single Gln173----Leu substitution in a strongly conserved sequence (Falson, P., Maffey, L., Conrath, K., and Boutry, M. (1991) J. Biol. Chem. 266, 287-293). This mutation is shown here to greatly modify the biphasic pattern of ATPase activity as a function of pH: (i) the shoulder observed at acidic pH is significantly increased; (ii) the main peak, at alkaline pH, is markedly lowered; (iii) the optimal pH is shifted from 8.8 to 7.7. The mutation lowers both apparent negative cooperativity and sensitivity to azide inhibition which concomitantly increase when the assay pH decreases. Azide partial inhibition produces apparent negative cooperativity which can be further abolished by bicarbonate. The mutation increases both activation energies determined from biphasic Arrhenius plots. The mutation decreases the inactivation rate by 5'-p-fluorosulfonylbenzoyladenosine and abolishes the protection by nucleotide binding at the adenine-specific regulatory site. On the contrary, it does not modify the reactivity of 5'-p-fluorosulfonylbenzoylguanosine at the less-selective catalytic site. In addition, partial inactivation by 5'-p-fluorosulfonylbenzoyladenosine, as opposed to 5'-p-fluorosulfonylbenzoylguanosine, produces apparent negative cooperativity under conditions where unmodified-enzyme kinetics are noncooperative. The results show that alpha-Gln173 participates in nucleotide interaction at a regulatory site which controls the negative cooperativity of F1-ATPase activity
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
Alpha subunit of mitochondrial F1-ATPase from the fission yeast. Deduced sequence of the wild type and identification of a mutation that alters apparent negative cooperativity
No full textThe nuclear gene atp1 encoding the mitochondrial ATP synthase alpha subunit of the fission yeast Schizosaccharomyces pombe was sequenced. It contains a 1,608-base pair-long open reading frame interrupted by two introns of 175 and 269 base pairs, located near the 5'-end of the gene. The initiation site of transcription AAAC was located 60 nucleotides upstream of the translation initiation codon. The deduced polypeptide sequence contains a 27-amino acid residue presequence, presumably involved in mitochondrial targeting, preceding a mature protein of 509 amino acid residues. The atp1 alleles from mutant A2313 (Bouty, M., and Goffeau, A. (1982) Eur. J. Biochem. 125, 471-477) and its related phenotypic revertant R351 (Falson, P., Di Pietro, A., Darbouret, D., Jault, J. M., Gautheron, D. C., Boutry, M., and Goffeau, A. (1987) Biochem. Biophys. Res. Commun. 148, 1182-1188) were also cloned and sequenced. A single nonsense mutation CAA-TAA (Gln173-stop) in mutant A2313 became a missense mutation TAA-TTA (stop-Leucine) in revertant R351. Glutamine 173 is located in the first putative element of the nucleotide binding site. Its substitution by a leucine residue appears responsible for the lower enzyme affinity toward ADP and for the loss of cooperativity of F1-ATPase activity
Beta subunit of mitochondrial F1-ATPase from the fission yeast. Deduced sequence of the wild type protein and identification of a mutation that increases nucleotide binding
No full textThe Schizosaccharomyces pombe nuclear gene, atp2, encoding the beta subunit of the mitochondrial ATP synthase, was sequenced and found to contain a 1575-bp open reading frame. Two adjacent transcription-initiation sites were found at positions 34 and 44 nucleotides upstream of the translation-initiation codon. The deduced polypeptide sequence was composed of 525 amino acid residues (molecular mass = 56875 Da). The mature polypeptide starts at residue 45 (molecular mass = 51,685 Da), indicating the presence of a presequence of 44 residues, presumably involved in mitochondrial targeting. The atp2 mutant B59-1 [Boutry, M. & Goffeau, A. (1982) Eur. J. Biochem. 125, 471-477] and its related revertant allele R4-3 [Jault, J. M., Di Pietro, A., Falson, P., Gautheron, D. C., Boutry, M. & Goffeau, A. (1989) Biochem. Biophys. Res. Commun. 158, 392-399] were also cloned and sequenced. A single nonsense mutation, CAG (Gln170)----TAG (stop) in mutant B59-1, became a missense mutation, TAG (stop)----TAC (Tyr) in revertant R4-3. Gln170 is located between the first and second elements belonging to the nucleotide-binding site. Its substitution by a tyrosine residue increases the enzyme affinity towards ADP, the amount of endogenous nucleotides and the apparent negative cooperativity for ATPase activity
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
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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