1,721,023 research outputs found
Presence of Pseudomonas syringae pv. actinidiae in buds of asymptomatic Actinidia chinensis var. deliciosa plants in late autumn and winter
No full textIn bacterial diseases, the latency period, during which there are no visible disease symptoms, can be prolonged depending on the conditions unfavorable for the growth of pathogens. As for Pseudomonas syringae pv. actinidiae (Psa), the causal agent of the bacterial canker of kiwifruit (BCK), the ability to survive several years in asymptomatic plants was recently highlighted. The Psa pluriannual latency in susceptible plants raises serious problems to control BCK for which it is necessary to consider defense strategies other than those based on spray treatments. Phytopatogenic bacteria can be hosted in buds of asymptomatic plants and their survival is regarded as a factor facilitating the overwintering of certain diseases caused by P. syringae. To clarify the bud epidemiological role, the Psa early detection in dormant buds (≈300) was carried out. In late autumn, 10 asymptomatic A. chinensis var. deliciosa plants were selected in an orchard located at the edge of a safety area that in the current year did not show BCK symptoms. At the beginning of dormancy (mid-December) and of “bleeding” (end of February), the buds were removed from a one-year old shoot. The Psa presence was determined by direct isolation and PCR analysis. At the end of the two surveys, the plant phytosanitary state was monitored to relate the orchard situation with the effective Psa absence/presence as pointed out by the early detection on bud samples. Psa was present in buds from 1 out of 10 and in 4 out of 10 plants in the first and in the second survey, respectively
Endophytic distribution of Pseudomonas syringae pv. actinidiae after a five-year latency into Actinidia chinensis var. chinensis plants: a real-time-PCR analysis
No full textThe ability of phytopathogenic bacteria to survive for long time within asymptomatic host plants represents one of the main critical factors to control outbreaks. The epidemiological role of the bacterial latency phase is very important since the control strategies are based on preventive chemical treatments by spraying on plant surfaces. In seven-year-old plants of Actinidia chinensis var. chinensis ‘Hort16A’ inoculated five years before with a virulent Pseudomonas syringae pv. actinidiae gfp-expressing/rifampicin-resistant strain (Psagfp-Rifres) at low inoculum dose, the dangerous latency phase of Psagfp-Rifres was studied dissecting the whole plants by cutting, from the apex to the root collar, the shoots/stems in segments of 20 cm (approx. 10-15/plant). In this study, to better clarify the endophyte distribution in asymptomatic plants and the preference of the pathogen for certain portions of the plant stem, the data previously obtained from microbiological (direct isolation on selective media, DI), biological (pathogenicity/HR assay) and PCR (Bio- and Nested) analyses were compared with those from Real-time PCR (RT-PCR) analysis. In the pathosystem Psa–Actinidia, the pathogen reached a high degree of pathoadaptation which is highlighted by the pluriannual latency period of Psa. The RT-PCR of the DNA extracted and quantified by the different segments of each entire plant confirmed the results previously obtained from microbiological and Bio/Nested PCR analyses and allowed to detect Psagfp-Rifres in segments of the stem that in Bio/Nested PCR analyses were Psagfp-Rifres-negative. Direct isolation revealed the Psagfp-Rifres presence in accordance with the RT-PCR data. The long time required for DI of Psagfp-Rifres from plant samples five years after the plant inoculation was largely compatible with the low concentrations of Psagfp-Rifres detected by RT-PCR
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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