1,720,979 research outputs found
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
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
Intracellular free calcium concentration in transected spinal axons
No full textAn increase in intracellular free calcium concentration (\rm\lbrack Ca\sp{2+}\rbrack\sb{i}) has been implicated in the degeneration of transected axons. We used fura-2 to measure the \rm\lbrack Ca\sp{2+}\rbrack\sb{i} in the last few mm of the proximal segments of transected spinal axons. There is a spatially graded increase in \rm\lbrack Ca\sp{2+}\rbrack\sb{i} that is complete within minutes; at 0.5 mm from the cut end, the \rm\lbrack Ca\sp{2+}\rbrack\sb{i} is 14 times greater than basal levels and at two mm, it is three times greater. Superimposed on this initial change is a moving front of calcium that progresses up the axon, reaching 1.6 mm from the cut end in three hours. In these regions, \rm\lbrack Ca\sp{2+}\rbrack\sb{i} exceeds what can be reliably measured with fura-2 (10 M). One day after transection, \rm\lbrack Ca\sp{2+}\rbrack\sb{i} returns to precut levels except in the distal 300 m indicating that the high levels of \rm\lbrack Ca\sp{2+}\rbrack\sb{i} do not result in the immediate destruction of the axon. The application of a DC electric field decreases or increases, depending on polarity, the penetration of the front of \rm Ca\sp{2+} into the axon. All of these changes in \rm\lbrack Ca\sp{2+}\rbrack\sb{i} that occur following transection require extracellular calcium
The role of calcium in the regulation of the cell cycle of Xenopus laevis embryos
No full textLevels of intracellular free calcium ( (Ca\sp{2+}\rbrack\sb{i}) in albino Xenopus laevis embryos were measured using aequorin and a photon-counting system. The recordings showed that there are sinusoidal oscillations (Ca\sp{2+}\rbrack\sb{i} having the same frequency as cleavage, with mitosis beginning after the peak of each (Ca\sp{2+}\rbrack\sb{i} cycle and cleavage occurring when (Ca\sp{2+}\rbrack\sb{i} is lowest. The (Ca\sp{2+}\rbrack\sb{i} oscillations are superimposed on a secondary pattern that increases, peaks between third and fifth cleavages and then declines to a level similar to that measured before first cleavage. The oscillations are due to release of calcium from intracellular stores, since the signal is the same in calcium-free solution as in normal medium. Similar calcium oscillations are present in embryos in which cleavage has been blocked with microtubule-disrupting drugs as well as in artificially activated eggs. In nondividing eggs and embryos the secondary pattern increases until about the third cycle and remains elevated for the duration of the recordings. Measurements of (Ca\sp{2+}\rbrack\sb{i} from different subregions of cleavage-blocked embryos shows that the calcium changes occur uniformly throughout the embryos, implying that the (Ca\sp{2+}\rbrack\sb{i} changes are uniform within individual blastomeres in cleaving eggs. When aequorin is injected into individual blastomeres of 64-cell embryos, the shapes of the signals are substantially different from those seen in recordings from whole embryos, indicating that (Ca\sp{2+}\rbrack\sb{i} increases are not uniform across the multicellular embryo but are localized. To investigate further the role of calcium in cell cycle control, I attempted to prevent calcium changes in cycling extracts prepared from Xenopus eggs by adding an antibody directed against phosphatidylinositol 4,5-bisphosphate (PIP\sb2), the precursor for the calcium-releasing second messenger, inositol 1,4,5-trisphosphate (IP\sb3). While the antibody slows cell cycle progression in these extracts, this is the result of an inhibition of protein synthesis rather than a specific effect on the cell cycle machinery. Subsequent experiments suggested that the inhibition of translation is not the result of the antibody blocking production of IP\sb3 or diacylglycerol, the byproducts of PIP\sb2 hydrolysis, although the exact mechanism is presently unclear
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