1,720,955 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
Influence of molecular structure on rheological and processing behaviour of molten polymers
No full textThe primary focus of this work was to study the effect of molecular characteristics of polymers
on their rheological and processing behaviour. In particular, the melt fracture and wall slip
phenomena have been extensively studied using various rheological tools and techniques. In
order to study the effects of the two key molecular characteristics, the weight average molecular
weight and the molecular weight distribution, two series of polyethylene resins have been
specially selected. A new method of interpretation of the large-amplitude oscillatory shear
(LAOS) data has been proposed. It provides an easier and more convenient way for the data
analysis suitable for use as a non-linear viscoelastic polymer characterisation technique. In
addition, this method has been shown to offer an alternative way for determination of the
damping function. Furthermore, a criterion for melt fracture performance has been developed
and it was found to be related to a characteristic relaxation time of polymers.
Additional experiments have been carried out with two metallocene polyethylene resins, which
exhibited unusually long start-up transients during their capillary extrusion. This phenomenon
has been investigated in detail and the results are explained in terms of a qualitative molecular
model based on the two mechanisms of slip, namely flow-induced chain detachment and
disentanglement.
A multimode dynamic slip model has also been developed and a procedure for the
determination of its parameters is proposed. The model has been found to provide better
predictions compared to a static and a single-mode slip models for the flow of molten
polymers in transient experiments under slip conditions.
Finally, a flow visualisation apparatus has been developed using a quartz capillary and
interrupted laser beam. It allowed the measurement of the velocity profiles at high
temperatures and shear stresses. Using this apparatus, the effect of processing aids on the flow
profile and melt fracture behaviour of molten polypropylene has been studied.Applied Science, Faculty ofChemical and Biological Engineering, Department ofGraduat
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
Melt fracture behaviour of molten polypropylenes
No full textExperiments were carried out in both sliding plate and capillary
I rheometers with two polypropylene resins to determine the conditions
for the onset of slip, surface and gross melt fracture. It was found that
there was no distinction between surface and gross melt fracture, which is
commonly observed in the case of polyethylenes. Furthermore, the flow curves
determined by using capillaries having various diameters are diameter independent,
implying the absence of slip. However, performing experiments with slit dies
having rough surfaces suggested the presence of wall slip. Further analysis has
shown that the effect of viscous heating masks the detection of slip from the
diameter dependency of the flow curves. The effect of presence of a thin layer of
fluoropolymer (Teflon® PA and Viton®, DuPont) on the critical shear stress for the
onset of wall slip and melt fracture as well as on the relationship between the wall
slip and the shear stress were also examined. It was found that the presence of such
layers increases the slip velocity while decreases the critical shear stress for the
onset of slip. Surprisingly, this reduction in the wall shear stress had no effect on
the critical shear rate for the onset of melt fracture.Applied Science, Faculty ofChemical and Biological Engineering, Department ofGraduat
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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