1,721,547 research outputs found
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
Testing the evolutionary link between submillimetre galaxies and quasars: CO observations of QSOs at z~2
Full text linkWe have used the IRAM Plateau de Bure millimetre interferometer and the UKIRT 1–5 μm Imager Spectrometer (UIST) to test the connection between the major phases of spheroid growth and nuclear accretion by mapping CO emission in nine submillimetre-detected QSOs at z= 1.7–2.6 with black hole (BH) masses derived from near-infrared spectroscopy. When combined with one QSO obtained from the literature, we present sensitive CO(3–2) or CO(2–1) observations of 10 submillimetre-detected QSOs selected at the epoch of peak activity in both QSOs and submillimetre (submm) galaxies (SMGs). CO is detected in 5/6 very optically luminous (MB∼−28) submm-detected QSOs with BH masses MBH≃ 109–1010 M⊙, confirming the presence of large gas reservoirs of Mgas≃ 3.4 × 1010 M⊙. Our BH masses and dynamical mass constraints on the host spheroids suggest, at face value, that these optically luminous QSOs at z= 2 lie about an order of magnitude above the local BH–spheroid relation, MBH/Msph, although this result is dependent on the size and inclination of the CO-emitting region. However, we find that their BH masses are ∼30 times too large and their surface density is ∼300 times too small to be related to typical SMGs in an evolutionary sequence. Conversely, we measure weaker CO emission in four fainter (MB∼−25) submm-detected QSOs with properties, BH masses (MBH≃ 5 × 108 M⊙), and surface densities similar to SMGs. These QSOs appear to lie near the local MBH/Msph relation, making them plausible ‘transition objects’ in the proposed evolutionary sequence linking QSOs to the formation of massive young galaxies and BHs at high redshift. We show that SMGs have a higher incidence of bimodal CO line profiles than seen in our QSO sample, which we interpret as an effect of their relative inclinations, with the QSOs seen more face-on. Finally, we find that the gas masses of the four fainter submm-detected QSOs imply that their star formation episodes could be sustained for ∼10 Myr, and are consistent with representing a phase in the formation of massive galaxies which overlaps a preceding SMG starburst phase, before subsequently evolving into a population of present-day massive ellipticals
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
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
The Evolutionary Status of Early-type Galaxies in Abell 2390
No full textWe explore the evolution of the early-type galaxy population in the rich cluster Abell 2390 at z=0.23. For this purpose, we have obtained spectroscopic data of 51 elliptical and lenticular galaxies with MOSCA at the 3.5 m telescope on Calar Alto Observatory. As our investigation spans both a broad range in luminosity (-22.
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
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