1,721,047 research outputs found
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
The presence of a p53-like protein during pea seed maturation and germination
No full textThe mechanisms that allow monitoring of DNA damage and the activation of repair systems in plants are poorly known. In mammalian cells the tumor suppressor protein p53 plays an important role in the checkpoint pathway induced by DNA damage. In this work, me investigated the presence and distribution of the p53-like protein in pea root tip nuclei and its role during early germination in relation to DNA damage. In pea seed, PFGE and TdT assays show that DNA fragmentation occurs during maturation and dry seed storage, and that this DNA fragmentation is repaired at the beginning of germination before the onset of proliferation. In the same seeds, the p53-like protein was found during maturation and germination. Immunoblotting characterization of this protein led to the identification of a single specific protein of about 94 kDa, more abundant at the beginning of the hydration process than in actively cycling cells. Furthermore, the p53-like protein revealed different nuclear distribution patterns, probably in relation to the formation of DNA fragments in dry seeds, and to the reactivation of repair mechanisms during early germination. These data suggest that the presence of a p53-like protein in quiescent or proliferating, pea embryo is related to DNA damage, and serves for the maintenance of genetic information and the development of normal seedlings
Natural hybridization in Saxifraga callosa Sm.
No full textSaxifraga callosa Sm. is an evergreen perennial species distributed from Eastern Spain, through the Western Alps and the Apennines, to southern Italy. The existence of high morphol. variation within different subspecies indicates that phenotypic characters are useful but not sufficient taxonomic tools. Indeed, available morphol. data already suggested that S. callosa subentity lantoscana may be an outcross between S. callosa and S. cochlearis. In this work, by analyzing ITS (Internal Transcribed Sequences), AFLP (Amplified Fragment Length Polymorphisms), and cpDNA (chloroplast DNA) markers, a comprehensive study of the genomic relationships among S. callosa and related species has been carried out. The sequence of the ITS region of S. callosa subentity lantoscana gave no conclusive results on the taxonomy status of S. callosa subentity lantoscana. On the other hand, the use of the \"NewHybrids\" software to analyze an AFLP data-set (208 polymorphic amplified fragments) supported a significant posterior probability that S. callosa subentity lantoscana individuals are natural hybrids between S. callosa and S. cochlearis. The level of introgression of genes from alien genomes was confirmed by a simpler and quick methodol. that analyze length variation in cpDNA sequences. [on SciFinder (R)
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
Chloroplast and nuclear DNA markers to characterize cultivated and spontaneous Ribes
No full textNine universal cpSSR markers were tested on a representative group of cultivated accessions and spontaneous ribespopulations. All primer combinations, with the exception of ccmp8, underwent amplification. Monomorphic alleles weredetected at the ccmp2, ccmp3, ccmp4, ccmp5, ccmp7, ccmp9 primer pairs. Two and four polymorphic alleles were observedat the ccmp6 and ccmp10 loci, respectively. These six alleles combined in five different haplotypes, two of which were foundin the cultivated accessions, and three only in the spontaneous populations. AFLP analysis was also performed to betterdefine the relationships among cultivated and spontaneous varieties, and to compare nuclear markers with chloroplastmicrosatellites. AFLP data were able to distinguish clearly all cultivars, while in spontaneous populations the detectedpolymorphisms were too low. In conclusion, cpSSR markers can be considered useful in the characterisation of ribesaccessions. Thus, the combination of this tool with nuclear markers, such as AFLP, could help in distinguishing andcharacterising each cultivated accession, and in defining population genetic parameters in the study of spontaneous Ribesspecie
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