1,720,957 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
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
Representation of the Convectively Coupled Kelvin Waves in Modern Reanalysis Products
No full textThesis (Master's)--University of Washington, 2022Despite decades of research, fundamental questions about the convectively coupled Kelvin waves (CCKWs) remain not fully answered, including the destabilization mechanisms and the mean state modulation. To deepen our understanding and to test simple models for CCKWs, in this study we examine CCKW precipitation, vertical structure, and energetics in four modern reanalyses (RAs): the fifth version of ECMWF Reanalysis (ERA5), NASA Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA-2), the second version of the NCEP Climate Forecast System Reanalysis (CFSR), and the Japanese 55-year Reanalysis (JRA-55). The CCKW precipitation signal strength in the wavenumber-frequency domain and the geographical distribution of CCKW precipitation variability are reasonably represented in all RAs, although they commonly underestimate the amplitude of CCKW precipitation. Despite considerable inter-RA differences in the vertical structure of temperature and diabatic heating anomalies, the eddy available potential energy (EAPE) generation within the CCKWs is found to be associated with the second baroclinic mode whereas the first baroclinic mode damps CCKW EAPE in three out of four RAs. Geographically, the positive CCKW EAPE generation within the second baroclinic mode occurs in areas with high mean state sea surface temperature (SST). Under higher mean state SST, stronger CCKW precipitation variability is preferred through a larger second mode EAPE generation, mainly due to a stronger stratiform heating and a tighter wave-convection coupling. Our results are supportive of the simple models for CCKWs in which CCKWs are destabilized within the second baroclinic mode component
Convectively Coupled Kelvin Waves in Current and Future Climates
No full textThesis (Ph.D.)--University of Washington, 2024Convectively coupled Kelvin waves (KWs) drive tropical precipitation variability on the subseasonal timescale. The KWs influence extreme rainfall and drought events, tropical cyclogenesis, and the Southeast Asian summer monsoon. Despite their profound impacts, the response of KWs in a warmer climate remains an open question due to an incomplete understanding of their dynamics. This study aims to better understand the maintenance and propagation mechanisms of KWs, as well as their response to global surface temperature changes, using observations and aquaplanet simulations. Previous studies suggest that KWs are maintained by two distinct processes: (1) the internal thermodynamic feedback between KW diabatic heating and temperature anomalies and (2) the external momentum forcing that midlatitude Rossby waves exert on KW zonal wind anomalies. However, the relative importance of the two processes is unknown. The relative importance of the two processes to KW maintenance is quantified by comparing the growth rate of eddy available potential energy (EAPE) and eddy kinetic energy (EKE) within KWs using satellite and reanalysis data. Results show that internal thermodynamic feedback is the dominant mechanism that maintains KWs in all regions and seasons. Among all regions, the external forcing is the least important over the Indian Ocean, possibly associated with the highest sea surface temperature and weakest westerly in the upper troposphere, enhancing diabatic heating and inhibiting midlatitude waves approaching the tropics. Results highlight the importance of understanding the convection-wave interaction within KWs in observations and numerical simulations.
To investigate changes in the maintenance and propagation of KWs in response to surface warming, I use a set of three aquaplanet simulations with varying sea surface temperature boundary conditions, representing the current climate, a warmer (+4K), and a cooler (-4K) climate. Results show that KWs accelerate at the rate of about 7.1%/K, and their amplitudes decrease by 4.7%/K. The dampening of KWs with warming is associated with a weakening of the internal thermodynamic feedback between diabatic heating and temperature anomalies that generates KW EAPE. The phase speed of KWs closely matches that of the second baroclinic mode KW in -4K, while the phase speed of KWs is approximately that of the first baroclinic mode KW in +4K. Meanwhile, the coupling between the two baroclinic modes weakens with warming. I hypothesize that in -4K, as the first and second baroclinic modes are strongly coupled, KWs destabilize by positive EAPE generation within the second baroclinic mode, and they propagate slower following the second baroclinic mode KW phase speed. In +4K, as the first and second baroclinic modes decouple, KWs are damped by negative EAPE generation within the first baroclinic mode, and they propagate faster following the first baroclinic mode KW phase speed.
Then, I examine what controls the coupling between the two modes and why the coupling weakens with warming. While previous simple models of KWs proposed several mechanisms for the coupling, none can fully explain my simulation results. My simulation results suggest the coupling mechanism involves the second baroclinic mode temperature anomalies that modulate deep convection by moistening the lower troposphere via vertical advection of moisture. As the surface warms, the second baroclinic mode diabatic heating anomalies have a weaker magnitude above the top of the boundary layer. With a weaker temperature perturbation in the lower free troposphere associated with it, the second baroclinic mode temperature anomalies appear to be less effective at triggering deep convection and weaken the coupling between the two baroclinic modes. The change in the structure of the second baroclinic mode temperature anomalies with warming is associated with the changes in the mean state temperature profile, especially the rise of the melting level. As the melting level rises, the peak of the second baroclinic mode cooling, which is contributed by melting, is located higher. Thus, the second baroclinic mode diabatic heating anomalies have a weaker magnitude above the top of the boundary layer. These results highlight that the lower tropospheric moistening is crucial to the coupling mechanism and, hence, the maintenance mechanism of KWs. Results suggest that accurate simulation of the mean state changes and the convection-wave coupling is the key to a reliable simulation of KWs
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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