1,720,954 research outputs found
Multi-target antimicrobial activity and molecular characterization of autochthonous bacteria strains from Vitis vinifera leaves to cope with biotic stresses
Full text linkIl progetto di tesi si proponeva di esplorare e studiare il microbioma autoctono del filloplano di Vitis vinifera al fine di identificare microrganismi con proprietà antimicrobiche ed il potenziale per essere utilizzati come agenti di controllo biologico (BCA) nei confronti di stress biotici. La Peronospora, causata da Plasmopara viticola, è stata scelta come caso studio per l'identificazione di BCA. P. viticola è un oomicete strettamente biotrofico che, nelle giuste condizioni ambientali, può attaccare tutti i tessuti verdi della pianta. Ad oggi, per evitare perdite di produttività, il controllo della malattia viene comunemente effettuato utilizzando prodotti chimici che, tuttavia, risultano dannosi per l'ambiente e per la salute umana e animale. L'identificazione di BCA contro P. viticola potrebbe promuovere pratiche più sostenibili in viticoltura come alternativa ecologica ai pesticidi chimici attualmente utilizzati. La prima fase delle attività di ricerca ha riguardato la selezione delle varietà di V. vinifera da cui isolare i microrganismi. La selezione è stata effettuata valutando il grado di tolleranza/suscettibilità delle diverse varietà alla Peronospora sui grappoli e sulle foglie, con la selezione finale di tre varietà: “Dawn seedless”, “Blush seedless” e “Argentina”. L'attenzione si è concentrata sulla componente batterica del microbioma delle foglie delle varietà scelte con conseguente isolamento, tramite un’analisi microbiologica, dei batteri epifiti ed endofiti. Sono stati eseguiti diversi saggi per identificare i candidati BCA. 16 dei batteri isolati sono stati testati su dischi fogliari per valutare la loro attività antagonista contro P. viticola e sono state definite diverse classi di efficacia in base al rapporto percentuale dell'area del disco fogliare coperta da sporulazione dell'oomicete. Cinque ceppi batterici ('BLG_B1.1.1', 'BLG_B1.3', 'BLG_B2', 'BLG_B4', 'BLG_B5') sono stati selezionati sulla base della loro diversa efficacia nel controllo dell'infezione di Peronospora e sono stati caratterizzati per le loro peculiarità morfologiche con successiva identificazione della specie di appartenenza. I cinque ceppi batterici sono stati poi testati con un saggio in vivo su foglie per studiare un possibile meccanismo d'azione contro P. viticola. In particolare, è stato valutato il loro effetto sull'espressione dei geni effettori di P. viticola PvRxLR28 e PvRxLR67 tramite esecuzione di una Real-Time PCR. Nello specifico, tra i cinque ceppi, si è osservato come tre determinassero una riduzione da moderata a elevata dell'espressione di PvRxLR28. È stata inoltre valutata la loro efficacia contro un'ampia gamma di patogeni fungini e la loro sicurezza per la salute umana. È stata infine eseguita un’analisi bioinformatica comparativa tra i ceppi ‘BLG_B2’ e ‘BLG_B4’, seguita da un saggio volto a valutare la loro capacità di contrastare la crescita di batteri patogeni per l’uomo. Le prospettive future del presente lavoro prevedono che i potenziali BCA identificati siano testati su piante per valutare il loro effetto sulla resistenza di V. vinifera a condizioni patologiche che colpiscono il filloplano e la carposfera. A tal fine, è stata condotta una prova pilota in campo su piante testando una comunità microbica sintetica già caratterizzata per le sue proprietà di biocontrollo. I risultati della prova consentiranno di definire i migliori protocolli per replicare in futuro la prova utilizzando i candidati BCA batterici selezionati.This thesis aimed to explore and study the autochthonous microbiome of Vitis vinifera phylloplane to identify microorganisms with antimicrobial properties and the potential to be used as Biological Control Agents (BCAs) to cope with biotic stresses. Downy Mildew, caused by Plasmopara viticola was selected as a case study for the identification of BCAs. P. viticola is a strictly biotrophic oomycete that can attack all the plant’s green tissues in the right environmental conditions. Nowadays, to avoid yield losses, disease control is commonly carried out by using chemical products that are harmful to the environment and to human and animal health. The identification of BCAs against P. viticola could promote more sustainable practices in viticulture as an eco-friendly alternative to currently used chemical pesticides. The first step of the research activities was the selection of the V. vinifera varieties from which microorganisms would be isolated. The selection was carried out by evaluating the degree of tolerance/susceptibility of the different varieties to Downy Mildew on the bunches and leaves and finally, three varieties were selected: ‘Dawn seedless’, ‘Blush seedless’ and ‘Argentina’. Focus was brought on the bacterial component of the leaves microbiome of the chosen varieties and epiphytic and endophytic bacteria were isolated through a microbiological analysis. Different assays were performed to identify candidate BCAs. Sixteen among the total isolated bacteria were tested on leaf discs to evaluate their antagonistic activity against P. viticola and different classes of efficacy were defined according to the percentage ratio of the leaf disc area covered by the oomycete sporulation. Five bacterial strains (‘BLG_B1.1.1’, ‘BLG_B1.3’, ‘BLG_B2’, ‘BLG_B4’, ‘BLG_B5’) were selected on the basis of their different efficacy in controlling Downy Mildew infection and were characterized for their morphological features and their species was identified. The five bacterial strains were tested through an in vivo assay on leaves to study a possible mechanism of action against P. viticola. In particular, their effect on the expression of P. viticola effector genes PvRxLR28 and PvRxLR67 was assessed by performing a Real-Time PCR. Among the five strains, three determined a moderate to high reduction of PvRxLR28 expression. Moreover, their effectiveness against a wide range of fungal pathogens and their safety to human health was also evaluated. A bioinformatic comparative analysis between the strains ‘BLG_B2’ and ‘BLG_B4’ was performed, followed by an evaluation of their ability to counteract the growth of human pathogenic bacteria. Future perspectives of the present work involve testing the identified potential BCAs on plants to evaluate their effect on V. vinifera resistance against plant diseases affecting the phylloplane and carposphere. A pilot field trial on plants was carried out testing a synthetic microbial community already characterized for its biocontrol properties. Results will allow the definition of the best protocols to replicate the trial using the selected candidate bacterial BCAs
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
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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