1,720,958 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Exploring Mechanisms of Chemical Resistance in Xanthomonas Arboricola pv. Pruni and Strategies to Mitigate Resistance and Improve Disease Control
No full textXanthomonas arboricola pv. pruni (XAP) is a phytopathogenic bacterium that causes bacterial spot of peach. It causes spotted lesions on leaves and fruit, leading to early defoliation and unmarketable fruit, respectively. The pathogen can overwinter in twig cankers, which serve as the primary initial inoculum source for the next season’s leaf and fruitlet infection. The current disease management practice mainly relies on routine application of chemical bactericides containing copper or oxytetracycline (OTC) in the growing season. However, disease incidence can still be high despite chemical control measures in warm, rainy seasons.
Frequent applications of copper and OTC in United States peach orchards are alarming for resistance development that copper tolerance and OTC resistance has previously been reported in peach orchards of South Carolina. In this study, we surveyed the prevalence of copper tolerant and OTC resistant XAP strains in South Carolina and Georgia peach orchards (Chapter 2), developed PMA-qPCR assay to quantify viable XAP (chapter 3), compared the overwintering capability of these resistant/tolerant strains with the sensitive XAP strains (Chapter 4), and identified the genetic determinants for the copper resistance in a XAP strain (Chapter 5).
From Orchard surveys during 2021-2024, 1,739 XAP isolates were collected from four South Carolina and three Georgia peach farms and screened on copper (0, 38, 44, and 51 µg/ml Cu2+) or OTC (25 µg/ml) amended nutrient agar (NA). Among the isolates tested, 95.6% were low copper tolerant (grown on NA amended with 38 µg/ml Cu2+), 5.8% were high copper tolerant (grown on NA amended with 51µg/ml Cu2+), and 24.9% were OTC resistant (grown on NA amended with 25 µg/ml of OTC). The resistant/tolerant XAP population has increased or been maintained over the years in these orchards.
To study the overwintering capability of XAP strains, a long-amplicon propidium monoazide (PMA)–quantitative PCR (qPCR) assay was developed. This assay enabled sensitive, specific, and accurate quantification of viable XAP cells as low as 103 CFU/ml with the presence of up to 107 CFU/ml of dead XAP cells, while suppressing the amplification of DNA from dead cells. With the PMA-qPCR assay, we studied the survival of XAP strains with different chemical sensitivities on peach trees after inoculation during bud set, after harvest, and leaf drop in fall. Resulted showed that the inoculation during leaf drop and after harvest led to significantly more twig canker and overwintered XAP on peach twigs than the bud set inoculation. No difference was observed in overwintering capability of XAP strains with different chemical sensitivities, suggesting that these OTC-resistant and copper-tolerant strains may persist and accumulate in peach orchards across seasons.
Genome sequence analysis of a copper resistant XAP strain revealed a ~249 kb plasmid carrying large duplicated clusters of copper resistant genes, including copL, copA, copB, copC,copD, copM, copG, copF, cusA and cusB. Gene functional analysis revealed that copL-D were the major contributors to copper resistance. Addition of copL doubled the copper resistance level compared to copA-D alone. Duplication of this copper resistance gene cluster increased the resistance level compared to the single copy, while deletion of both copies of this cluster caused the loss of copper resistance. The copper resistant genes and phenotypes were able to be transferred to Xanthomonas perforans via conjugation.
In conclusion, this study showed that OTC resistance and low level of copper tolerance is persistent in the peach orchards regardless of spray programs, indicating the need of new management options for peach production. Leaf drop and after harvest periods were identified as important time for XAP to establish in peach twigs for overwintering survival. These results, in combination with our first report on the copper resistance mechanism in XAP, provide new knowledge to improve our understanding of epidemiology and genetics of the chemical resistant/tolerant XAP population and will contribute to the future development of more sustainable disease management program to reduce XAP inoculum sources and minimize disease development
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe 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
Sustainable Approaches to the Management of Soilborne Diseases in Nursery Production
No full textDiseases caused by soilborne pathogens are a major limitation to field grown nursery production. The application of cover crops for soilborne disease management has not been widely investigated in woody ornamental nursery production system. Experiments were conducted to improve soilborne disease management efficiency through effective utilization of cover crops in nursery production and, to identify pathogens affecting ginkgo (Ginkgo biloba L.) and red maple (Acer rubrum L.) plants in nurseries of Tennessee and develop fungicide/biofungicide management recommendations for nursery producers. To determine the impact of cover crop in nursery production systems, soils from red maple production sites with and without cover crops [crimson clover (Trifolium incarnatum L.) or triticale (×Triticosecale W.)] were sampled following the senescence of the cover crops. Separate bioassays were performed using red maple cuttings on inoculated [with P. vexans, Phytophthora nicotianae (Breda de Haan) or Rhizoctonia solani (J.G. Kühn)] and non-inoculated field soils. The results indicated that winter cover crop usage was beneficial for inducing soil disease suppressiveness. There were lower disease severity and pathogen recovery with cover crops compared to the non-cover cropped soil. The rhizosphere pseudomonad microbial population was also greater when the cover crops were used. Similarly, the carbon and nitrogen (C:N) ratio of the soil was improved with the cover crop usage. Thus, in addition to improving soil structure and reducing erosion, cover crops can provide improved management of soilborne diseases. to identify pathogens affecting ginkgo (Ginkgo biloba L.) and red maple (Acer rubrum L.) plants in nurseries of Tennessee, morphological identification and sequence analysis of their internal transcribed spacer (ITS) regions, and large subunit (LSU) of the nuclear ribosomal RNA (rRNA), cytochrome c oxidase subunit I (Cox I) and cytochrome c oxidase subunit II (Cox II) of mitochondrial DNA (mtDNA) were done. Based on sequence results, Phytopythium vexans (de Bary) was described from the infected ginkgo and red maple plants. In addition, the efficacy of fungicides, biofungicides, fertilizer and host-plant defense inducers (traditionally recommended for management of oomycete diseases) for control of Phytopythium crown and root rot were evaluated on ginkgo and red maple ‘October Glory’ seedlings in greenhouse and field trials. Empress Intrinsic, Pageant Intrinsic, Segovis and Subdue MAXX fungicides were effective in both greenhouse and field trials, and the biofungicide Stargus reduced disease severity caused by pathogen P. vexans on ginkgo and red maple plants in greenhouse trials. These results will help nursery producers make proper management decisions for newly reported Phytopythium crown and root rot disease, and also Phytophthora and Rhizoctonia root rot of nursery crops
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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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