1,720,972 research outputs found
A novel gene-fusing vector: construction of a 5-GGmCC-specific chimeric methyltransferase, M.BspRI/M.BsuRI
No full textA vector was designed to allow predetermined and precise fusion between two cloned genes by constructing a cassette with two unique class-IIS restriction sites, 5'-ACCTGC-3' (BspMI) and 5'-CCGGATG-3' (FokI overlapping with MspI), arranged back-to-back in a divergent manner and inserted at the HincII site of a multiple cloning site (MCS) in plasmid pUC18 or analogous vehicle. Two DNA fragments or genes to be precisely fused are cloned into the MCS parts located on each side of the cassette containing the two unique class-IIS restriction sites. The BspMI and MspI/FokI sites are used to generate unidirectional deletions of the genes as previously described [Hasan et al., Gene 50 (1986) 55-62; Posfai and Szybalski, Nucleic Acids Res. 16 (1988) 6245]. The precisely trimmed genes are ligated after the cassette containing the unique class-IIS restriction sites are excised with BspMI+ FokI and the termini were blunted with mung-bean nuceleast. This method was used to construct a hybrid methyltransferase (MTase) from the M. BspRI and M. BsuRI MTases, which share a high degree of overall homology (about 65%) and have the identical sequence specificity (5'-GGmCC-3'). A hybrid MTase composed of the N-terminal part of M . BspRI and the C-terminal part of M . BsuRI was constructed and found to be fully functional
Cre/loxP-mediated in vivo excision and amplification of large genomic segments of S.cerevisiae and an attempt their amplification using the Fip/FRT/2 mu ori system
No full textCre/loxP-mediated in vivo excision of large segments from yeast genome and their amplification based on the 2 mu m plasmid-derived system
No full textIn vivo excision and amplification of pre-determined, large genomic segments, directly from the genome of a natural host, provides an alternative to conventional cloning in foreign vectors. Using this approach, we have devised an in vivo procedure for excising large segments of Saccharomyces cerevisiae genome using Cre/loxP system of bacteriophage P1, followed by amplification of excised circles, as based on the yeast 2 mu m plasmid-derived ori and Flp/FRT machinery. To provide the excision and replication enzymes, trans-acting genes cre and FLP, which were under a very tight control of GAL1 and GAL10 promoters; respectively, were inserted by homologous recombination into the URA3 gene on chromosome V. Two parallel loxP sequences, which serve as the recognition sites for the Cre recombinase, were also integrated into the genome at pre-determined sites that are 50-100 kb apart. Moreover, 2 mu m ori, REP3 and two inverted FRTs, which serve as a conditional replication system, were also integrated between the loxP sites. The strain carrying all these inserted elements was perfectly stable. Only after the induction by galactose of the Cre excision function, the genomic segment flanked by two loxP sites was excised and circularized. Applying this procedure, the 50-kb LEU2-YCR011c and 100-kb LEU2-YCR035c regions of chromosome III were successfully excised from the S. cerevisiae genome, whereas the 2 mu m ori, as aided by FRT/Flp, provided the amplification function. Such excised and amplified genomic segments can be used for the sequencing and functional analysis of any yeast genes. (C) 1998 Elsevier Science B.V. All rights reserved
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
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
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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