1,720,973 research outputs found
Extragalactic jets as current carrying systems. II - Magnetohydrodynamic turbulence, relativistic electron distribution, and observable quantities
No full textA Comprehensive Statistical Analysis of the Gas Distribution in Lyman Limit and Damped Lyα Absorption Systems
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Gas and Star Formation in M33: An Artistic Pathway
Get PDFM33 is the closest blue, star forming, flocculent spiral galaxy for which it has been possible to combine an overwhelming quantity of multiwavelength high resolution data to shed light on its assembly and star formation across cosmic time. I will summarize some of the key ingredients related to the formation and evolution of this galaxy, such as its dark matter, the baryonic distribution and the metallicity gradients. M33 is a pure disk galaxy with a lower baryonic fraction than M31, of order 0.02, and a dark matter profile typical of structure growth in ΛCDM cosmology. Disk dynamics and the growth of perturbations can be visualized in a detailed 2-D map. The consequent star forming sites across the disk, analyzed using mid-infrared observations, points out young stellar clusters spanning 4 orders of magnitude in luminosity. This database has allowed to study IMF sampling at the high mass end and the concept of a cluster birthline. Stars and gas, present beyond 2-optical radii, point out to the occurrence of possible cosmic gas infall fueling star formation. Bruce Elmegreen’s outstanding contribution to science becomes evident in the analysis of M33, here underlined also through an artistic pathway
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
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