1,720,966 research outputs found
Expression of Protein L-Isoaspartyl Methyltransferase in sunflower seeds as affected by ageing and priming
No full textIn orthodox seeds, non-enzymatic protein damage occurring during dehydration and storage is hypothesized to be a main cause of deterioration. Therefore, for vigorous germination dry seeds should be equipped with protein repair mechanisms. One of these involves protein L-isoaspartyl methyltransferase (PIMT) which counteracts protein misfolding by catalyzing the conversion of abnormal L-isoaspartyl residues to their regular form. PIMT activity is primarily localized in seed tissues during and after maturation desiccation, suggesting its involvement in restoring the functional conformation of the seed proteome. This study was initiated to assess the putative role of PIMT repair pathway on seed vigor in Helianthus annuus whose seeds are rather sensitive to deterioration during storage. A sunflower homolog of Arabidopsis PIMT1 was isolated and characterized, and its expression in seeds was measured by qRT-PCR on a panel of 16 inbred lines subjected to ageing, priming, and priming after-ageing. The wide variability in the physiological response observed among the lines and the considerable interactions between factors produced a rather complex picture. Considered separately, ageing and priming had expected, although only modest, effects on final germination, i.e. negative the former (-2.4%) and positive the latter (+4.7%). More marked were the effects on germination rate, with an 8.3% increase in T50 after ageing and a 30.6% reduction after priming. On average PIMT transcript levels were highest in quiescent seeds and reached the minimum after ageing, with a 38% drop; also after priming PIMT mRNA decreased 26%, while in primed after-ageing seeds its abundance was variously affected. Therefore PIMT expression pattern in sunflower resembles that of other protein transcripts with protective role in dry seeds. Correlations between transcript levels and germination percentage and rate were not found in control and aged seeds; on the contrary, correlations were negative and significant when priming was applied, perhaps indicating either an attempted repair response or a reduced degradation in damaged tissues. For the complexity of the responses observed, further studies on gene expression and enzyme activity will be necessary to assess the role of this repair mechanism in maintaining seed vigor in sunflower
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
A RAPID IDENTIFICATION TOOL FOR ITALIAN LANDRACES AND OLD VARIETIES OF TRITICUM
No full textGenetic diversity is one of the key factors for the future of agriculture and food security,
making continuous crop improvements possible. Also in this perspective, EU legislation promotes
landrace conservation through the use of ‘Protected Designation of Origin’ (PDO) labels on derived
products and by allowing the production and exchange of landrace seed in their area of origin,
derogating from the requirements for variety registration. The availability of molecular marker
systems efficient in assessing genetic diversity is relevant for the safeguar of ‘varieties adapted to
the local and regional conditions and threatened by genetic erosion’, supporting their maintenance
and exploitation over the long term. In this work, 17 accessions of Triticum turgidum, belonging to
both durum and turanicum subspecies, and 14 of T. aestivum, including landraces and old cultivars,
were analyzed with two multiplex SSR sets made up in total of 12 markers. The two marker sets
had been previously used to characterize two larger panels including the most prominent durum and
bread wheat varieties presently commercialized in Italy. Heterogeneity was observed in most of the
landraces, with several non-fixed loci (up to 5 alleles per locus were scored), whereas accessions of
T. turanicum as well as old improved varieties of T. aestivum turned out basically uniform. In total,
70 alleles were detected in T. turgidum and 87 in T. aestivum accessions; of them 31 and 22 had not
been previously encountered in current varieties of the two respective species, indicating a
considerable loss of variability over time, particularly for the former. The greater allelic richness
found in T. aestivum compared to T. turgidum was also reflected by the higher mean level of
informativeness (PIC values of 0.72 and 0.56, respectively). Interestingly, the two SSR sets
allowed the distinction of all T. aestivum accessions, except two old varieties, whereas in T.
turgidum four were those undistinguishable. In conclusion, the two marker sets appear suitable for a
rapid assessment of wheat germplasm collections, and could be useful for the management of
specialty products, ensuring traceability over the whole production chain thus increasing their value
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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