1,720,987 research outputs found
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
Pressurized liquid extraction of chlormequat and mepiquat from cereal flours followed by LC tandem MS analysis
No full textA new analytical method for the rapid extraction and unequivocal confirmation of herbicides chlormequat (CQ) and mepiquat (MQ) in wheat flours and various flours utilized in infant foods was developed.
The extraction procedure is based on pressurized liquid extraction (PLE), using ethanol as extractant at high pressure and temperatures; the extraction rapidity is combined with the elevated selectivity and sensibility of the LC-MS-MS.
Analytes were separated by ion exchange chromatography and d9-chlormequat was used as internal standard.
Mass-spectrometric detection was conducted with a triple quadrupole equipped with a TurboIonSpray source operating in positive ionization mode.
Two Selected Reaction Monitoring (SRM) were chosen for each analyte and the developed analytical method was validated by evaluating recovery, precision, linear dynamic range, sensitivity, limit of detection (LOD) and limit of quantitation (LOQ).
Special emphasis was placed on the versatility and robustness of automated PLE for routine trace determination of the selected analytes; moreover, the use of ethanol allowed one to inject the sample directly, avoiding the evaporation step.
In particular, the study addresses the impact of the food matrix on ion suppression by comparing solvent calibration curves with those obtained by blank extracts, spiked with analytes. Calibration curves in matrix displayed a slope lower of about 20% than that noticed in the solvent.
Recoveries ranged from 83 to 99% at a fortification level of 10 ppb, corresponding to the maximum residue limit established by the European Union, while intra-day precision was less than 10% for all samples.
The developed method was applied to detect the incidental presence of MQ and CQ in different cereal flours.
In particular, traces of the selected herbicides were detected in about 50% of baby foods
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
Analysis of carotenoids and fat-soluble vitamins in selected plant food by matrix solid phase dispersion followed by liquid chromatography with DAD tandem MS detection
No full textMulti-vitamin determination, especially in unfortified food, is a complex analytical problem because of two main difficulties which make uneasy to find common extraction and chromatographic conditions: the chemical heterogeneity of analytes and their linkage with matrix macromolecular components. For these reasons, the number of publications in this research area is still limited and the official current procedures are based on individual HPLC analysis. Only few works are focused on the concurrent determination of fat-soluble vitamins and carotenoids by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS), either including a limited number of analytes or being based on two different extraction procedures. A LC-DAD-Tandem MS method has been developed for the simultaneous determination of eleven compounds, among fat-soluble vitamins (retinol, α-tocopherol, δ-tocopherol, γ-tocopherol, ergocalciferol, phylloquinone and menaquinone-4) and carotenoids (lutein, zeaxanthin, β-carotene and lycopene), in various foods of plant origin such as maize flour, tomato pulp, green and golden kiwi. Analytes were separated on a C30 reversed-phase column and unequivocally identified by atmospheric pressure chemical ionization (APCI) tandem mass spectrometry. The extraction/clean-up procedure was performed applying the Matrix Solid Phase Dispersion (MSPD) technique with recoveries ranged between 60 and 80%, depending on the matrix selected, and an inter-day precision less than 12%.The coupling of DAD with MS resulted an effective tool for obtaining a qualitative profile of fat-soluble vitaminis and carotenoids occurring in every food, concurrently to the quantitative determination of the target analytes performed by MS detector; moreover, it allowed the carotenoids identification, whose standards are not commercially available. During real samples analysis, menaquinone-4, supposed to have a bacterial origin only, was unexpectedly identified in all foods under study
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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