1,721,930 research outputs found
Insecticide activitiy of Mediterranean essential oils
No full textVapours of essential oils, extracted from 12 Mediterranean plants of the families Lamiaceae, Verbenaceae and Apiaceae, were assayed for insecticide activity against the aphid pests Acyrthosiphon pisum (Harris) and Myzus persicae (Sulzer). Different doses were applied, starting from 2 ml/l air and halving the dose until no activity was registered. Anise, fennel and basil essential oils resulted in high mortality, even applied at low doses. Activity was dose-dependent. The occurrence of phytotoxicity following the application of some essential oil is discussed. In spite of the well-known drawbacks owing to phytotoxicity, the application of essential oils in the control of pests on plants appears feasible
Bioassay-oriented isolation of an insecticide from Ailanthus altissima
No full textThe tree-of-heaven, Ailanthus altissima Swingle(Simaroubaceae), was studied for its potential insecticide activity against the pea aphid, Acyrtosiphon pisum (Harris). First instar aphids were dipped in water solutions of root extract and of leaf extract of A. altissima, and this was followed by bioassay-oriented fractioning of leaf extract (more active in bioassays) with petroleum ether, chloroform, chloroform-methanol, methanol and water, and of chromatographic fractions. The putative active constituent ailanthone, isolated from the plant resulting in the highest aphid mortality, has been assayed as a pure compound in different concentrations, proving to be responsible, for the insecticidal activity reported
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
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
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
Tra non voto e rete. La partecipazione politica in Italia dalla Prima alla Seconda Repubblica
No full textIl saggio analizza le specificità della partecipazione politica in Italia, focalizzando l'attenzione sul nuovo significato del non voto e sulle potenzialità delle nuove tecnologie della comunicazion
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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