1,721,026 research outputs found
A comparative study on the efficacy of semi-purified, viral glycoproteins as antigen in the indirect hemagglutination test for pseudorabies antibody
Full text linkCloning and characterisation of gene coding for chitinase in developing winged bean seed
Full text linkThe cloning of potentially useful genes for increased resistance to pest and diseases in crop plants
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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
Molecular genetic studies on Brassica napus L.
Full text linkThe feasibility of using two different methods of assaying for DNA polymer phisms has been assessed. They were Restriction fragment length polymorphisms (RFLPs) as revealed by a range of characterised Brassica cDNA sequences and Random amplified polymorphic DNA (RAPD). These techniques have been shown to reveal DNA polymorphisms between varieties of Brassica napus L.. Further more, the sequence and organisation of a Hind III family of highly repetitive DNA sequences were also studied on Brassica napus L. RFLPs associated with rape extensin, ext A, and Brassica oleraceae self- incompatibility genes were observed when DNA samples from 19 commercial varieties of B. napus were analysed using the cDNA probes pRR566 (coding for root-specific extensin) and pBOS2 (coding for S(_5) self-incompatibility allele in B. oleraceae). Both cDNA clones were able to reveal RFLP patterns with varying degrees of polymorphism depending on the restriction enzymes used in the digestion of genomic DNAs. Although both probes could generate complex RFLP band patterns, those revealed by pB0S2 were generally easier to analyse and more suitable for DNA fingerprinting while those revealed by pRR566 were less distinct as a result of extensive background hybridisations. The probe pRR566, with certain restriction enzymes generated simpler RFLP band patterns that were more suitable for segregation analyses. Segregation analysis of F(_1) individuals revealed additive RFLP band patterns of both parental varieties, while that of F(_2) individuals revealed RFLP band patterns of each parental varieties as well as the additive pattern. When analysed for possible association with varietal glucosinolate content, none of the RFLP band patterns showed such linkage. A cDNA library was constructed from pod material of a high glucosinolate variety in an attempt to obtain clones which could reveal RFLP patterns associated with glucosinolate content. Differential screening using total cDNAs from pod materials of high and low glucosinolate varieties failed to isolate any cDNA clones useful as RFLP markers. Another DNA polymorphism assay studied, RAPD, was able to detect inter- and intraspecific variation in Brassica sp.. Analysis of six phylogenetically-related but distinct Brassica sp. revealed extensive variation in the RAPD band patternsof amplification products; with some amphidiploid species sharing conserved band patterns with their ancestral species. RAPD analysis on 17 varieties of rape revealed polymorphic as well as highly conserved RAPD band patterns depending on the primer used. One of the primers was able to amplify a polymorphic band which could be associated with low glucosinolate varieties i.e. present almost exclusively in low glucosinolate varieties. Species-specific as well as variety-specific band patterns were also observed during the RAPD analysis. Finally, sequence and organisation of a Hind III family of repetitive sequences was studied. The monomeric and polymeric forms (trimer and tetramer) of the repetitive sequences were successfully cloned into pUCl8. Sequence analysis of the two clones containing the polymeric forms revealed that the monomers were arranged in tandem array and that all internal Hind III recognition sites were lost due to point mutation(s) which occurred within the six basepair recognition site. A consensus monomeric sequence was deduced from sequence comparison of the 8 copies of the monomeric sequences present in the 3 clones and the deviation from the consensus sequence of each of the eight monomers was less than 3%. No two monomeric sequences were identical. It was estimated that the number of copies of the monomeric sequences in a haploid genome was approximately 0.3 million copies. Estimates of the proportional representation of each of the polymeric sequences based on the number of copies of the monomers in each polymer were also calculated
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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