1,721,107 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
The last gift of BeppoSAX: PDS observations of the two blazars 1ES 0507-040 and PKS 1229-021
No full textTowards the end of the BeppoSAX mission, the only operated Narrow Field Instrument was the PDS, which covers the energy range 13-300 keV. Two blazars, 1ES 0507-040 (z=0.304) and PKS 1229-021 (z=1.045), suitably located in the sky for BeppoSAX pointing, were observed for about 2 days each in Spring 2002 with the PDS and detected up to 50 keV. 1ES0507-040 had already been observed by the BeppoSAX NFIs at an earlier epoch for a much shorter time. We have re-analysed those data as well, and identified a possible contamination problem in the PDS spectrum. We present our recent PDS data on both sources, combined with the previous BeppoSAX data and with non-simultaneous observations at other frequencies. The derived Spectral Energy Distributions allow us to discuss the origin of the high energy component
The X-ray emission of Intermediate Polars: the BeppoSAX view and the role of current missions
No full textIntermediate Polars (IPs) are the most intriguing systems among Cataclysmic Variables (CVs), as the X-ray spectral and temporal behaviour is not similar in all members. The simultaneous study of broad-band X-ray temporal and spectral properties is crucial to characterize the accretion geometry and the physical conditions of the accretion flow onto moderately (B<10-20 MG) magnetized white dwarfs. Thanks to the wide energy coverage, BeppoSAX observations of bright IPs have allowed to infer the accretion mode, the presence of complex patchy absorption in the pre-shock flow and of a Compton reflection component from the white dwarf surface as well as to measure simultaneously the temperature of the post-shock region and that of the irradiated poles of the white dwarf atmosphere. The observations show that accretion in these systems cannot be reconciled with a single scenario, accounting for their soft and hard X-ray behaviour. Many known systems and IP candidates still lack of X-ray characterization in both soft and hard bands, for which current X-ray missions are providing new and unprecedented results
X-ray broad band spectral Properties of Intermediate Polars
No full textWe summarize the broad band spectral properties of a small sample of bright Intermediate Polars studied with BeppoSAX
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
- …
