1,720,965 research outputs found
Simulations of the NGC-5466 tidal stream in a Galactic-like potential, with and without dwarf galaxies included
No full textA mock stream of NGC-5466 simulated with the particle-spray code `galpy.df.streamspraydf`, which is an implementation of the Fardal et al 2015 mock stream generation method. The current position and velocity of the progenitor globular cluster is from Vasiliev et al 2019. The progenitor's orbit is back-integrated 5 Gyr in a `galpy.potential.MWPotential2014` potential then forward integrated, forming the tidal tails. The file with the name 'dwarfgalaxy' includes the effects of dwarf galaxies on the stream. For more information see (and cite) https://ui.adsabs.harvard.edu/abs/2022MNRAS.510.2437E.The included files have been modified by Nathaniel Starkman (ORCID: 0000-0003-3954-3291) to be in an ECSV format
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
Charting the Stellar Streams of the Milky Way
Full text linkWith massive datasets, we can now study Galactic halo structures in unprecedented detail, incorporating kinematic information alongside positions and photometry. However, the data are low-signal, noisy, and high-dimensional, making it challenging to detect, characterize, or model these halo structures like stellar streams. In this thesis I tackle these challenges by employing statistical approaches to astrophysical observations and developing novel data-driven methods to characterize and model stellar streams of the Galaxy. I also release open-source software to reproduce the work in this thesis.
Stellar streams encode information about their progenitor systems and the Galaxy they orbit. Using Gaia data, including kinematics, I extend the detected Pal 5 stream’s tidal tails to approx- imately 30 degrees, with a newly detected 7-degree segment in the leading arm. This extended detection provides insights into the stream’s interactions with the Galactic bar and the Galaxy’s gravitational potential. Following this detection, I develop novel methods for characterizing stellar streams. One method, using machine learning and time-series analysis, constructs parametric stream paths. This method accounts for measurement errors and data sparsity, is independent of Galactic models, and is applicable to phase-wrapped streams. I develop another method for characterizing observed stellar streams, combining Bayesian models and machine learning. This method simultaneously operates on astrometric and photometric data to detect streams in very low signal-to-noise fields and provides a comprehensive characterization of the stream’s properties, independent of Galaxy models. It handles incomplete phase-space observations. I apply this method to GD-1 and Pal 5 to start building a homogeneous catalog of stellar membership probabilities. Finally, I develop a probabilistic framework to constrain the Galactic potential using the developing catalog of stellar stream observations. By comparing observed stream data to forward models, my methodology aims to identify the underlying parameters of the Galaxy’s potential and its orbiting clusters. This framework already provides informative constraints on components such as halo mass, triaxiality, and Galactic bar rotation, laying the foundation for expanding the catalog to improve constraints and sensitivity to additional Galactic components.Ph.D
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
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