1,720,980 research outputs found
Malattia del Pinot grigio, nuova emergenza sulla vite.
No full textI rilievi svolti hanno messo in evidenza che l'incidenza di GPGV (il virus del Pinot grigio) è in espansione, in particolare sui giovani impianti. la sua diffusione è probabilmente legata al materiale di propagazione utilizzato. Non è invece certa la capacità di trasmissione dell'acaro eriofide Columeris vitis, aspetto questo da indagare ulteriormente
Influenza delle infezioni da virus e fitoplasmi sull'interazione portinnesto/varietà.
No full textNell'articolo vengono descritte le interazioni fra portinnesti di drupacee e pomacee ed agenti patogeni (virus e fitoplasmi) diffusibili e non diffusibili in natura. In riferimento all' influenza di tali malattie infettive sull'affinità vegeto-produttiva degli alberi da frutto, risulta evidente la necessità di utilizzare per l'attività vivaistica materiale controllato dal punto di vista sanitario
A multiplex Real Time Taqman RT-PCR assay for the detection of grapevine flavescence doree and bois noir phytoplasmas using crude sap extracts.
No full textFlavescence dorée (FD) and Bois noir (BN) are the most important and spread grapevine yellows diseases in Europe and are caused by phytoplasmas of the 16SrV and 16SrXII-A groups, respectively. Detection of BN and FD phytoplasmas is particularly difficult, as they are generally present in low concentrations and unevenly distributed in the grapevine phloem. Many efforts recently focused on developing of a rapid and sensitive method for phytoplasma detection. In this study a triplex real time TaqMan RT-PCR methodology has been set up to simultaneously, but specifically, amplify a 16SrDNA gene fragment of FD and BN phytoplasmas and a 18SrDNA gene region of the host plant using a crude sap extract as template. The use of RNA as template, instead of DNA, takes advantage from the high ribosomal-RNA copy number present in pathogen cells and provides an evidence of viability and metabolic activity of phytoplasma, which is not provided by DNA-based detection. During our study an efficient and rapid method for GY phytoplasmas detection in different host plants has been obtained. Absence of nucleic acid extraction step allows to greatly decrease both costs and time necessary to perform the assay. Therefore the method presented is a rapid, specific and sensitive alternative to conventional nested-PCR. We successfully applied this technique to the detection of BN and FD phytoplasmas on more than three hundred samples of grapevine, strawberry, tomato, wild host plants and vector insects
Evaluation of Plum Pox Virus sensibility on different stone fruit varieties in Emilia-Romagna region (Italy)
No full textBetween 2003 and 2011, about 200 stone fruit varieties were inoculated by chip budding with PPV M strain, grown in a screen house and then surveyed for symptom expression on leaves, flowers and fruits. During the following season in particular 126 peach and nectarine, 45 apricot and 28 plum varieties and seedlings (from breeding programs) under evaluation were assessed in the present work. A large number of varieties showed discoloration and mottling on the young leaves in spring; furthermore all peach and nectarine selections with rosaceous flowers appeared infected by PPV with strong symptoms on petals. Many peach and apricot cultivars and seedlings, but only one plum variety, presented fruit deformations with typical rings and mottling.
Only a few accessions (2 peaches and 10 apricots) belonging to “ancient” germplasm or to seedlings did not appear affected by typical symptoms on leaves and fruits, nor were positive to PPV by ELISA and Real Time RT-PCR assays. These experimental data revealed high sensibility of stone fruit germplasm to PPV-M as confirmed by the information gathered in the Emilia-Romagna region, by inspectors of the local Plant Protection Service. In particular during 15 years of orchards surveys 36 varieties of apricot, 37 of plum, 102 of nectarine and 83 of peach (both traditional and promising varieties) were infected, showing typical symptoms, as a result of the natural PPV spread in the field
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
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