1,720,956 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
The Viscosities of dry and hydrous XAlSi3O8 (X=Li, Na, K, Ca0.5, Mg0.5) melts
No full textThe low-temperature viscosities of dry and hydrous X (X=Li, Na, K, Ca0.5, Mg0.5)AlSi3O8 melts have been investigated. The samples were hydrated via piston cylinder synthesis, and the water contents were subsequently determined
by Karl-Fischer titration (KFT) and IR spectroscopy. Both the anhydrous and hydrous viscosities were measured using the
micropenetration technique in the range of viscosities between 108.5 to 1011.9 Pa s, at 1 atm pressure and in the temperature ranges of 745–990 °C and 400–790°C for the dry and wet melts, respectively. The range of water content varied for all of the
samples from 0.70 to 3.13 wt.% H2O. The viscosities of dry melts vary, at fixed temperature, as a complex function of the identity of the cation in the order Li<Na<Ca<Mg<K. This trend is interpreted as due to the combined effects of cation
field strength and (Si, Al) distribution in these melts.
With the introduction of water into these melts, the viscosity decreases for all of the compositions investigated. As water
is further dissolved, the array of anhydrous viscosities converges into two distinct curves, for alkali-bearing and
alkaline-earth-bearing aluminosilicate liquids, respectively. In contrast to the insensitivity of viscosity to alkali cation
identity for hydrous melts, the alkali-aluminium ratio remains a sensitive control on viscosity. Thus, the viscosities of a
slightly peralkaline albite glass (Naexc)are lower than all of the others, both for the dry and the hydrous systems. We suggest that, in the case of alkaline-earth-bearing melts, an aluminium pair must be closely related to a doubly charged cation, to maintain electrostatic neutrality. The increase in the size of smallest rearranging species, which participates in the viscous flow process, as well as clustering of silica-rich and alumina-rich domains on an Aintermediate-rangeB scale, may be the factors resulting in the higher viscosities of Ca- and Mg-bearing compared to alkali-bearing liquids
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
The dry and hydrous viscosities of alkaline melts from Vesuvius and Phlegrean Fields
No full textSophisticated models of volcanic scenarios are increasingly sensitive to the accuracy of their input parameters and constitutive equations for magma properties. Viscosity is certainly one of the most important magma properties, but only recently systematic investigations on silicate liquids with natural compositions have started. We investigated the Newtonian
viscosity of dry and hydrous phonolitic and trachytic melts from Vesuvius and Phlegrean Fields volcanic complexes, respectively. The analysed samples come from the deposits of the AD 1631 (Vesuvius) and ca. 4400 BP Agnano Monte Spina (AMS) (Phlegrean Fields) eruptions that are commonly taken as reference events for the most hazardous scenarios in case of
reactivation of the two volcanoes. Samples were hydrated via piston cylinder synthesis at P= 10 kbar and T = 1600 °C. The dry high temperature and dry or hydrous low temperature viscosities were measured by a combination of micropenetration and
concentric cylinder techniques, covering a total temperature range from about 400 to 1500 °C, water content range from virtually dry to 3.8 wt.%, and viscosity range from 102 to 1012 Pa s. The viscosity data for each composition were fitted by a
modified Tamman–Vogel–Fulcher equation, allowing viscosity calculations at eruption temperatures and for dissolved water contents in the range of those examined. The viscosity data and model calculations were used for a comparison with other
natural or synthetic phonolitic and trachytic melts, as well as with rhyolitic melts, for which viscosities had been measured. At water contents less than 1 wt.%, a trend of increasing viscosity from phonolitic to trachytic to rhyolitic melts is found. At water contents larger than 1 wt.%, the viscosity of trachytic melts is close to that of rhyolitic melts, while the viscosity of phonolitic melts is one to two orders of magnitude lower. A compositional parameter given by the (Na +K+ H)/(Si + Al) molar ratio is found to be linearly related to the low-T hydrous viscosity of the trachytic and phonolitic melts considered, either analysed in
this work or taken from literature. Differently, the rhyolitic melt shows significant variations from the trend found for phonolitic
and trachytic melts
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
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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