1,721,072 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
Development of a numerical kinetic model and its application to dusty gas cometary atmospheres.
No full textThis dissertation presents a newly developed model of inner and outer comae and results of its application for comets Borrelly, Hyakutake and Churyumov-Gerasimenko. A kinetic approach is the most convenient one to describe significantly different flow regimes and processes occurring in a coma. During the work on the dissertation a general-purpose multiphase kinetic flow solver that can be applied to a wide range of multidimensional problems was developed. The numerical tool is implemented on massively parallel computers and can be used for simulation of a multi-species gas flow on an unstructured mesh with an arbitrarily complex geometry of the boundary and boundary conditions. The new element that makes the newly developed model different from other available models of cometary comae is the kinetic representation of the dust phase in a flow that also allows simulation of an extended source of volatiles in the coma. During this study the structure of cometary comae was simulated starting from the surface of the nucleus and extending up to 106 km. Six species (H2O, CO, OH, H2, O, H) were included into the model. The intermolecular momentum exchange, energy exchange between internal degrees of freedom and radiative cooling were taken into consideration. The coma model takes photochemical processes into account. Numerical study indicated that the combination of photodissociation and momentum exchange in the collisionally transitional region results in significant variations of macroscopic parameters in the gas phase of the outer coma. Nonsublimating dust and sublimating icy grains were included into the model as the second phase. The dusty-gas environment of comet Borrelly was modeled. It was used to analyze images taken with the MICAS camera on the Deep Space 1 spacecraft. The study of the grain acceleration in the innermost coma was performed. It was found that the grains reach their terminal velocities within 10 radii of the nucleus. Sublimation of icy grains contributes to the extended source of volatiles in the coma. The study of variation of icy grains characteristic size and mean radial velocity with the distance from the nucleus was performed. The influence of the extended source on the distribution of macroscopic parameters in a coma was studied for the case of comet Hyakutake. It was found that the extended source significantly influences the distribution of the radial velocity and temperature of the gas phase in the coma. A model study of the Rosetta mission target comet Churyumov-Gerasomenko was performed to specify the gas environment of the comet throughout the mission from the initial encounter to the perihelion.PhDAstronomyPure SciencesUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/125901/2/3224762.pd
The magnetohydrodynamics of cometary plasma.
No full textUnderstanding of the cometary plasma environment, an ideal laboratory for magnetohydrodynamic (MHD) study, has great value in plasma physics. This dissertation presents a collection of 3-D global mass-loaded ideal MHD studies of this environment with a multi-scale grid system resolving both the bow shock and contact surface. Using the single and multi-species versions of this model as well as steady-state and time-dependent solutions, the dynamic structures, mass loading process, tail dynamics, and ion chemistry are advanced through theoretical parameter studies and direct model-data comparisons. With the single species version of this model, the importance of mass loading on the appearance of the plasma distribution, marked by the density and pressure distribution, as well as the dynamic structures, are presented as a good reference for future studies. The density and velocity measurements of comet 19P/Borrelly by the Deep Space 1 spacecraft are reproduced by our MHD model. The role of the neutral density distribution, which is the source of mass loading, on the plasma distribution, is advanced via such comparisons. Predictions of the plasma environment around comet 67P/Churyumov-Gerasimenko are also provided for four key locations during the Rosetta mission. The dynamic evolution of the cornetary plasma tail is also presented in the study of disconnection events (DEs). With heliospheric current sheet (HCS) crossings represented by a tangential discontinuity, our model reproduced the real-time evolution images of such DEs accompanied by magnetic reconnections. A CME-comet interaction has also been studied for the first time with reasonable comparison to some images. The first three-dimensional multi-species MHD model has been applied to the solar wind-comet interaction. In addition to reproducing the 1-species result, good agreement with Giotto proton densitv measurements can be obtained by estimating the hydrogen neutral distribution with the Haser model. The 6-species model considers the water group and CO group chemistry and suggests that in the inner coma, elastic collisions between ions and neutrals are more efficient in momentum transfer than the charge-exchange processes, which creates the major ion, H3O+. Compared with the single-species MHD model, such a 6-species MHD model is better able to provide the locations of cometopause and collisionopause.PhDAstronomyPure SciencesUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/126729/2/3276195.pd
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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