1,721,046 research outputs found
Elastic properties of hexagonal columnar mesophase self-organized from amphiphilic supramolecular columns
No full textBy direct imaging, we evaluate the relative stiffness of a hexagonal columnar mesophase induced by the self-organization of amphiphilic columnar supramolecules, both quantitatively and qualitatively, based on examination of the planar texture, and of defects contained therein. Quantitative measurement was performed by an analysis of distortions around edge dislocations. The elastic anisotropy varies significantly with the degree of molecular association. The columnar supramolecule containing rigid tapered molecules is stiffer than weakly associated self-assembled macromolecules by an order, resulting in different stability of the mesophase. In addition, defect characteristics are examined to further understand these supramolecular assemblies and their elastic properties. Highly resolved +1/2 disclinations have been observed in the flexible columnar supramolecules. (C) 2002 American Institute of Physics.This work was supported in part by the Korea Science &
Engineering Foundation through Ultra-microchemical Process
Systems, the Brain Korea 21 Program, and NSF Grants
Nos. DMR-8920147, DMR-9708581 and DMR-99-96288
Apparent tricritical behavior at a nearly second-order nematic-isotropic phase transition of a cyclic liquid crystalline trimer
No full textAn investigation on the cyclic liquid crystalline trimer TPB-(c)9(3) was performed. The optical retardation and Fréedericksz techniques within a few tens of millikelvins of the superheating limit of the nearly second-order nematic isotropic phase transition were used for the investigation purpose. It was found that both the Fréedericksz bend threshold voltage and optical retardation were in good agreement with tricritical behaviour for the transition. Appropriate bibliographic citation and notice of the APS copyright must be included- "Syed I.M., Percec V., Petschek R.G., Rosenblatt C., Physical Review E - Statistical, Nonlinear, and Soft Matter Physics 67:1, 117041-117044 (2003). Copyright 2003 by the American Physical Society.
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
Surface order in thin films of self-assembled columnar liquid crystals
No full textThe way in which alignment of hexagonal columnar mesophases depends on molecular structure, film thickness, and surface interactions is investigated. Homeotropic orientation of tapered nonpolymeric and polymeric amphiphilic columnar molecules occurs most readily on carbon substrates. The planar alignment of asymmetric dendrimers is favored on a water surface but is not possible for a symmetric dendrimer. For the polymeric material, film thickness has a significant influence on the morphology. Thick films align homeotropically, but films that are only a few column diameters in thickness are planar, and their thickness is quantized. Because they must contain an integral number of layers of cylinders, the resulting morphology is terraced.This work was supported by the
Center for Ultramicrochemical Process Systems, Advanced
Backbone IT Technology Development Project,
the Brain Korea 21 Project, and NSF (DMR-99-96288)
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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