1,720,965 research outputs found
Nano-demixing as a novel strategy for magnetic field responsive systems: the case of dibutyl phosphate/bis(2-ethylhexyl)amine systems
No full textPure surfactant liquids and their binary mixtures, owing to the amphiphilic nature of the molecules involved,
can exhibit nano-segregation and peculiar transport properties. The possibility of opportunely choosing the
amphiphiles should lead to the formation of anisotropic aggregates that can be oriented by an external
factor like a magnetic field. In this case some properties, like optical birefringence, can be induced by
the use of a magnetic field. Dynamic features of dibutyl phosphate (DBP)/bis(2-ethylhexyl)amine (BEEA)
mixtures have been investigated by FT-IR, NMR, rheometry, Brillouin scattering, and magneticallyinduced
birefringence measurements as a function of the BEEA mole fraction (X). It turns out that BEEA/
DBP liquid mixtures, driven by H-bond formation, show zero-threshold percolating self-assembly with
a maximum in viscosity and a minimum in molecular diffusion at 1 : 1 composition. Interestingly, it has
been highlighted that nano-segregation takes place at X y 0.7 with the formation of DBP-rich closed
local structures that are fully-responsive to an external magnetic field, rendering the system birefringent.
It is worth noting that this is the first observation of amphiphile-based micelles in amphiphilic medium.
The analysis of all the experimental data consistently pointed out the microscopic factors involved in this
peculiar phenomenon and in particular emphasized the role of specific polar and apolar interactions
along with to steric effects in regulating the molecular organization in surfactant mixtures. This report
presents novel clear, stable and anhydrous systems, fully responsive to a magnetic field with tunable
optical birefringence, and opens new trends in the directed design of water-free optically-active fluids
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
Emerging dynamics in surfactant-based liquid mixtures: Octanoic acid/bis(2-ethylhexyl) amine systems
No full textThis work focuses on the dynamic phenomena emerging in self-assembled transient intermolecular
networks formed when two different surfactants are mixed. In particular, the relaxation processes
in liquid mixtures composed by bis(2-ethylhexyl)amine (BEEA) and octanoic acid (OA) in
the whole composition range has been investigated by dielectric spectroscopy and Brillouin spectroscopy.
A thorough analysis of all the experimental data consistently suggests that, mainly driven
by acid-base interactions arising when the two surfactants are mixed, supra-molecular aggregates
formation causes the slowing down of molecular dynamics. This, in turn, reflects to longer-range
relaxations. These changes have been found to be composition-dependent, involving strong departures
of the mixture physico-chemical properties from an ideal behaviour, and reflecting the structural
and dynamical features of local structures. In particular, the peculiar dynamic processes occurring
in these local inter-molecular structures, have been found to be the factors responsible for
the observed and quite surprising increase of direct-current conductivity which occurs when two
different (and pretty non-conductive) surfactants are mixed. The discovery can be used not only
to design novel materials for application purposes but also to shed more light on the basic principles
regulating charge migration in structured liquid systems
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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