1,721,022 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
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
First report of 'Candidatus Phytoplasma fraxini' (group 16SrVII phytoplasma) associated with a peach disease in Canada.
No full textPeach (Prunus persica), family Rosaceae, is native to China. In Canada, the province of Ontario produces 82% of the nation’s peach crop. The Canadian Clonal Genebank, also located in Ontario, currently holds 83 accessions of peach. The collection is routinely monitored for symptoms of phytoplasma including decline (Fig. 1), leaf reddening (Fig. 2), yellowing, shortening of internodes, witches’ broom and reduced fruit size.
Leaf samples from trees exhibiting symptoms and symptomless trees representing sixteen accessions were collected from June to August 2009. Total DNA was extracted (DNeasy plant extraction kit, QIAGEN). Phytoplasma universal primers specific for 16S rDNA (R16mF2/R1 and R16F2n/R2; Gundersen & Lee, 1996) were used in a nested PCR assay. Nested PCR products of expected size (~1250 bp) were obtained for accessions PRU0430 (cv. HW274, from Canada), PRU0380 (cv. GF 305 from France), PRU0334 (cv. RedSkin from USA), PRU0155 (cv. Harblaze from Canada) and PRU0375 (cv. Babygold #5 from USA). Symptomless plants yielded no PCR products. Amplicons were purified (Wizard PCR Clean-up, Promega), cloned (pGEM-T Easy Vector, Promega), and sequenced (Robarts Institute, London, Canada). The obtained sequences shared 100% identity with each other and a representative corresponding to PRU0430 was deposited in GenBank (Accession No. GU223903).
BLAST analysis showed that the Prunus phytoplasma shared 99% 16S rDNA sequence identity with those of phytoplasmas in the group 16SrVII (ash yellows) for which ‘Candidatus Phytoplasma fraxini’ is the reference strain. Restriction fragment length polymorphism analysis (RFLP) of amplicons using AluI, RsaI and MseI yielded profiles similar to those of 16SrVII-A phytoplasma subgroup. Phytoplasmas of group 16SrVII have been reported in different hosts in Colombia, Argentina, Brazil and Chile (Fiore et al., 2007). Particularly in North America, including Canada, 16SrVII phytoplasmas have been associated with ash yellows and lilac witches’ broom diseases (Sinclair et al., 1996; Griffiths et al., 1999). To our knowledge, this is the first report of a 16SrVII-related phytoplasma strain identified in peach after an incidental report in peach in Southern Italy (Paltrineri et al., 2003). The 16SrVII phytoplasma has caused devastating effects in ornamentals. Therefore its presence in peach is of great phytosanitary significance due to its commercial interest, and represents a potential threat for disease spread to other fruit crops, particularly Prunus sp
Genetic diversity of phytoplasmas identified in peach (Prunus persica) accessions at the Canadian Clonal Genebank.
No full textPeach [Prunus persica (L.) Bastch] is mainly cultivated in Canada in Ontario province (82% of national production). A variety of symptoms typical of a phytoplasma infection were observed some of the 83 P. persica accessions during June-August 2009 at the Canadian Clonal Genebank. PRU0430 (‘HW274’, from Canada), PRU0380 (‘GF305’ from France), PRU0334 (‘RedSkin’ from USA), PRU0155 (‘Harblaze’, from Canada) and PRU0375 (‘Babygold #5’, from USA) showed decline, leaf reddening, yellowing, shortening of internodes, witches’ broom and reduced fruit size; while ‘PRU0382’ (peach-almond ‘Kando’ from the Czech Republic) and PRU0445 (peach ‘HW271’ from Canada) exhibited peach rosette-like symptoms. Leaf samples from symptomatic and symptomless plants were collected and total DNA was extracted. Phytoplasma universal 16S rRNA primers, R16mF2/R1 and R16F2n/R2 and fU5/rU3 were used in nested PCR assays. R16F2n/R2 nested PCR products were obtained for ‘PRU0430’, ‘PRU0380’, ‘PRU0155’, ‘PRU0334’ and ‘PRU0375’; while fU5/rU3 PCR products were obtained for ‘PRU0382’ and ‘PRU0445’. Plants lacking symptoms yielded no PCR products. Amplicons were purified, cloned, and sequenced. BLAST analysis showed that R16F2n/R2 sequences (GU223903) were 99% identical to 16S rRNA phytoplasma sequences for group 16SrVII ‘Candidatus Phytoplasma fraxini’, while those from fU5/rU3 amplicons (GU223904) shared 99% identity with those of group 16SrI ‘Candidatus Phytoplasma asteris’. AluI, RsaI and MseI RFLP analysis yielded profiles consistent with those of phytoplasma in subgroups 16SrVII-A and 16SrI-B, respectively. To our knowledge, this is the first report of a 16SrI-related phytoplasma in peach in Canada, and the first world report of a 16SrVII-related phytoplasma strain identified in peach after a case in southern Italy
Caratterizzazione molecolare di ‘Candidatus Phytoplasma asteris’ in ortensia in Canada
No full textHydrangea species are infected by phytoplasmas belonging to subgroups 16SrI-A and
16SrI-B (aster yellows) inducing phyllody and virescence worldwide. In Japan some of
the phytoplasma associated such disease were classified as ‘Candidatus Phytoplasma
japonicum’, moreover 16SrXII-A phytoplasmas were identified in Bulgaria and
more recently in Italy. The hydrangea phyllody disease was associated with 16SrI-B
phytoplasmas in Canada, however no fine molecular characterization was carried
out on the phytoplasmas in that country. Hydrangeas showing symptoms similar to
those associated with phytoplasma diseases were found and collected from landscape
areas in South-western Ontario, Canada. Phytoplasmas belonging aster yellows group
were detected in all symptomatic samples tested by two different methodologies.
Direct sequencing and sequence obtained after cloning of the 16Sr DNA gene show
confirmation of reported classification and the amplification and sequencing of groEL
gene confirm previous classification in subgroup 16SrI-B and allow to enclose aster
yellows phytoplasmas in hydrangeas from Canada in the groELI-III group that up to
now was only detected in Europe
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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