1,720,973 research outputs found
New images from the UKST H alpha survey
No full textDespite the obvious vital importance of star formation for the evolution of the structure of our Galaxy (and other spirals), general surveys of star forming regions within the Galaxy are remarkable for their paucity. In particular, no complete large scale, yet detailed survey in H alpha emission-the prime optical indicator of star formation and general ionized gas-has yet been carried out.The Anglo-Australian Observatory is currently working on a new H alpha survey of the Southern Galactic Plane using the U.K. Schmidt Telescope with a narrow band H alpha filter. The survey will consist of some 200 fields, separated by 4 degrees rather than the usual 5 degrees due to the physical size of the filter. Prior to the commencement of the full survey, a number of H alpha films were obtained on behalf of the original "H-alpha Consortium". It is from these films that the images presented here are taken.</p
The Westerbork HI survey of irregular and spiral galaxies, WHISP
No full textThis paper briefly describes WHISP, an ongoing project to image the HI in a large sample of nearby galaxies with the Westerbork Synthesis Radio Telescope (WSRT). The goal of the survey is to investigate the HI density distributions and velocity fields of galaxies as a function of Hubble type, luminosity and environment. The main emphasis so far has been on using HI kinematics to determine the mass distributions of galaxies, though other projects have been carried out with the WHISP data and axe briefly described.</p
The Westerbork HI survey of irregular and spiral galaxies, WHISP
No full textThis paper briefly describes WHISP, an ongoing project to image the HI in a large sample of nearby galaxies with the Westerbork Synthesis Radio Telescope (WSRT). The goal of the survey is to investigate the HI density distributions and velocity fields of galaxies as a function of Hubble type, luminosity and environment. The main emphasis so far has been on using HI kinematics to determine the mass distributions of galaxies, though other projects have been carried out with the WHISP data and axe briefly described.</p
The AAO/UKST H alpha survey
No full textThe UK Schmidt Telescope (UKST) of the Anglo-Australian Observatory (AAO) commenced, in July 1997, an H alpha survey of the Southern Galactic Plane and Magellanic Clouds. It uses a high specification, single-element interference filter of exceptional quality which was specially designed for the purpose. With a clear aperture of more than 305mm on a square 360 x 360 glass RG610 substrate, it is almost certainly the largest of its type in astronomy. With fine grained Kodak Tech Pan film-based emulsion as the detector, a survey with an unique combination of coverage, sensitivity and resolution will be produced, superior to any other survey of ionized hydrogen gas in terms of these combined properties. The survey currently comprises 233 Galactic Plane and 40 Magellanic Cloud fields on 4-degree centres and is expected to take 3 years to complete. The survey may be produced on him according to demand. However, the prime aim is the release of a fully calibrated digital survey based on SuperCOSMOS scans of the original films at 10 mu m (0.67arcsec) resolution as a CDrom or equivalent atlas. This is the first time that a UKST survey will be primarily released in digital form for the astronomical community. e The survey will be a valuable astronomical resource for a wide range of projects dealing with star formation, the interstellar medium (ISM) and galactic structure. Many discoveries have already been made. Here we present examples and results of new resolved planetary nebulae, together with brief details of other areas of research with Herbig Hare objects, supernova remnants and work in the Magellanic Clouds.</p
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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