1,720,958 research outputs found
Characterization of oxygen heterocyclic compounds and volatile fraction of Citrus australasica finger lime peel essential oil exploiting a multi-technique chromatographic approach
No full textAn investigation into cold-pressed finger lime essential oils (Citrus australasica) was conducted utilizing both liquid and gas chromatographic techniques. Samples were collected throughout the entire productive season, spanning from October 2022 to June 2023. This research aimed to elucidate the composition of non-volatile oxygen heterocyclic components using RP-HPLC-QqQ/MS and to analyze the volatile fraction using GC-FID. Additionally, the enantiomeric ratios of selected volatile components were determined through multidimensional GC (MDGC) with a chiral column in the second dimension. This study provides insight into the composition of Calabrian finger lime essential oils, offering valuable information for identifying quality parameters, essential for the analytical characterization of this product. To the best of the authors’ knowledge, this is the first report characterizing coumarins and furocoumarins in cold-pressed finger lime essential oils. Furthermore, the investigation includes the analysis of thirteen chiral couples, eight of which for the first time in the literature
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
Chemical characterization of Anthemis parlatoreana fresh and dried aerial parts by GC and LC chromatographic techniques and evaluation of the antioxidant properties
No full textAnthemis parlatoreana was collected in the north west coast of Sicily. Fresh and dried aerial parts were subjected to distillation procedure for the extraction and isolation of essential oils. In both fresh and dried samples, the most abundant chemical classes were ketones and esters, represented to a greater extent by β-thujone and β-artemisia acetate, respectively. In dried vegetable material, a high content of α-pinene and δ3-carene was also registered. Aqueous, methanol and ethyl acetate extracts of aerial parts were also investigated in terms of polyphenolic content and antioxidant potential. All the extracts tested showed a quite different quali-quantitative profile and in terms of chemical classes, most of compounds belonged to the hydroxycinnamic class (15 compounds) followed by flavonoid one (11 compounds); the rest was comprised of 2 sequiterpenoids, 2 organic acids and 1 hydroxybenzoic acid derivative. Further, the dried methanolic followed by the dried aqueous extracts revealed the best quenching ability, whereas concerning iron chelating capacity, although all of them showed a marked capacity to disrupt or inhibit the formation of iron (II)-Ferrozine complex, a slight difference was observed between the dried and the fresh ones, since the former have a slightly higher chelating power than the latter
Profiling of seized Cannabis sativa L. flowering tops by means of microwave-assisted hydro distillation and gas chromatography analyses
No full text: This research aimed to support police forces in their battle against illicit drug trafficking by means of a multi-technique approach, based on gas chromatography. In detail, this study was focused on the profiling of volatile substances in narcotic Cannabis sativa L. flowering tops. For this purpose, the Scientific Investigation Department, RIS Carabinieri of Messina, provided 25 seized samples of Cannabis sativa L. The content of Δ9-tetrahydrocannabinol (THC), useful to classify cannabis plant as hemp (≤ 0.2 %) or as marijuana (> 0.2 %), was investigated. Essential oils of illicit drug samples were extracted using a microwave-assisted hydro-distillation (MAHD) system; GC-MS and GC-FID analytical techniques were used for the characterization of the terpenes and terpenoids fingerprint. Furthermore, the enantiomeric and carbon isotopic ratios of selected chiral compounds were investigated using a heart-cutting multidimensional GC (MDGC) approach. The latter exploited a combination of an apolar column in the first dimension, and a chiral cyclodextrin-based column in the second one, prior to parallel isotope-ratio mass spectrometry (C-IRMS) and MS detection. Finally, all the data were gathered into a statistical model, to demonstrate the existence of useful parameters to be used for the classification of seized samples
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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