1,721,067 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
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
Windows into Alien Worlds: Modeling and Characterizing Substellar Atmospheres
No full textAtmospheres constitute the only accessible layer for observation from space, and their properties are linked to objects' formation and evolution, surface and interior processes, and habitability. Exoplanets and brown dwarfs are difficult to observe, but they provide a vast and varied data set which compliments insights gleaned from the small number of Solar System planets. This dissertation encompasses a series of studies all related to modeling, observing, and understanding substellar atmospheres. I present results from four publications and one project still in progress, as well as a full update to the opacity tables paired with the atmosphere codes used in this work: coolTLUSTY and METIS. All studies put a particular emphasis on anticipating new insights that may be gained from upcoming missions: direct imaging of mature giant exoplanet's reflecting starlight and direct imaging of young self-luminous exoplanets with the optical coronagraph on the Nancy Grace Roman Space telescope, transit spectroscopy of cloudy, tidally-locked warm exoplanets with the James Webb Space Telescope, and finally spectra of cool Y dwarfs, also a prime target for the James Webb Space Telescope
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
Simulations of Gravitational Lensing, and Other Lensing Systems
No full textI discuss the phenomenon of gravitational lensing, starting with fundamental principles of light and lenses and moving on to the necessary tools of General Relativity.
Along the way, I stress the connections between these gravitational lenses, classical
lenses, and atmospheric refraction. My motivation is to use the relevant equations to
write a computer program to simulate these lensing effects. The general algorithm for
this program is explained, and its results are qualitatively analyzed and checked against
existing programs
Towards an Understanding of Core-Collapse Supernovae
No full textThe explosion mechanism of core-collapse supernovae (CCSNe) is a long-standing astrophysical problem buttressed with over half a century of computational research. Neutrino heating of the collapsing mantle, wherein a fraction of the profuse neutrino luminosity in a collapsing star deposits energy onto the stalled shock, remains the preferred explosion mechanism for garden-variety CCSNe. Recent improvements in neutrino physics and in supercomputer power jointly ushered in new capabilities for the study of CCSNe. F{\sc{ornax}} is an optimized state-of-the-art hydrodynamics/radiative transfer code with detailed microphysics and scalable design that effectively takes advantage of these developments. I implement F{\sc{ornax}} to provide a comprehensive, multi-dimensional study of CCSNe horizontally-integrated, across a a broad suite of progenitor stars, and vertically-integrated, from explosion mechanism to observational signatures.
I provide a broad introduction of the topic, the code F{\sc{ornax}}, and the rich history of research in CCSNe in Chapter\,\ref{ch:intro}. Chapter\,\ref{ch:micro} looks at the sensitive dependence of explosion outcome on neutrino microphysics, in particular the role of many-body interactions and inelastic neutrino scattering. Chapter\,\ref{ch:2D} builds on these results to identify drivers of explosion outcome in a series of 2D axisymmetric simulations. Chapter\,\ref{ch:3D} introduces the first 3D simulation by F{\sc{ornax}}. A 16-M progenitor is carried out to roughly one second post-bounce, exploding promptly and robustly. The results highlight the need to carry simulations out longer, to several seconds, to identify asymptotic explosion energies. In Chapter\,\ref{ch:obs}, I look at neutrino and gravitational wave observational signatures, and their correlations with core physical dynamics, with a series of 11 progenitors evolved in 3D. This is the largest suite of 3D simulations to date, allowing a study of global characteristics of a diverse set of progenitor stars. The synergistic study of neutrinos and gravitational waves in forthcoming detectors can be used to profitably study physical phenomena in the supernova core.
CCSNe study has followed a Maslow hierarchy in ambition: first, producing successful explosions; second, producing robust explosion energies, and lastly, producing CCSNe consistent with observable diagnostics. My thesis establishes well the first point, embarks on the second, and courts the third
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