1,720,957 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
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
Elucidating the Singlet Fission Mechanism with Time-Resolved Multi-Dimensional Spectroscopies
No full textSinglet fission (SF) can enhance light-conversion efficiencies by splitting high-energy photons
into multiple low-energy triplet excitons, preserving otherwise lost energy due to thermalization.
This can potentially improve efficiencies by 30% relative to the Shockley-Queisser limit in
single-junction solar cells, driving extensive research into suitable sensitizer materials. A
bottleneck of research is that strong coupling promotes efficient SF but also hinders separation
of generated triplets. Striking just the right balance is challenging, due to the multitude of
factors that may affect the sensitizers’ SF capabilities. Moreover, the presence of multiple dark
states in the initial stages of SF complicates its experimental evaluation in regards to those
critical factors.
This thesis aims to address these challenges by studying the impact of targeted system
modifications on the SF mechanism under weak coupling conditions using time-resolved
spectroscopic methods, such as transient absorption (TA) and two-dimensional electronic
spectroscopy (2DES). For example, the feasibility of intermolecular SF is studied in a
pentacene derivate, where acene faces are shielded with additional phenylene functional
groups that restrict interaction between chromophores. While SF is not observed in solution,
thin films of the materials dispersed in polymer matrices show SF rates (kSF) that follow a
Förster resonance energy transfer (FRET) scaling with the average chromophore separation
(R): kSF ∝ R-6
. In turn, the excitation-energy transfer (EET) mechanism acts as the rate-limiting
step to SF and enhances it in a similar fashion to how natural light-harvesting networks improve
energy flow in proteins: Singlet excitons are funneled by FRET to SF-reaction sites where it
can proceed with near-unity quantum yields.
More attention is directed towards intramolecular SF (i-SF) in spiro-linked dimers, consisting
of two modifiable chromophores covalently bound to a spiro-carbon linker. Through spectral
reconstruction and semi-classical simulations of 2DES signal responses, it is shown that the
linker provides a framework of weak coupling that is still strong enough to enable efficient i-SF.
Dimerization of two dissimilar chromophores into heterodimers finely and predictively tunes
the energetic driving force of i-SF, which shown to have a great impact on its rate and
efficiency. Hetero-oligomerization proves especially effective in furnishing i-SF sensitizers that
show improved triplet yields (≈174% yield for separated triplets) compared to their homodimeric counterparts, facilitated also by downhill EET. Direct control over the excitonic coupling
responsible for i-SF is achieved by additionally linking the individual chromophores via
molecular bridges; by modulating the dihedral geometry of chromophores, the strength of their
intramolecular coupling is directly affected. How this chemical modification translates to
changes in the excitonic coupling, and in turn, the i-SF process, is evaluated experimentally
II
using transient 2DES, which was implemented during this work. Through this advanced
spectroscopic method, a primarily direct i-SF mechanism is concluded for when chromophores
are in closer proximity. As the chromophores are further separated by insertion of molecular
bridges, direct i-SF becomes increasingly suppressed in favor of a super-exchange mediated
i-SF mechanism and the overall rate and efficiency of the excited-state process decreases.
Obtaining such high levels of mechanistic detail is usually reserved to theoretical studies, which
has been made possible by utilizing the extraordinaire selectivity of transient 2DES towards
excited state transitions, opening up the avenue to study SF or other excited-state phenomena
with unprecedented detail. Altogether, this thesis lays out the impact of excitonic coupling
(through dimer geometries), energetic driving force (through alterations of chemical
compositions), and excitation energy transfer on the outcome of singlet fission, understood
through the lens of multiple time-resolved spectroscopies. As demonstrated here, these
properties of nature act synergistically and can be utilized to improve the efficiency of (i-) SF,
providing insight into molecular design principles for organic materials intended for applications
in solar energy technologies
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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