1,721,086 research outputs found
An empirical study of dust properties at the earliest epochs
Full text linkWe present an empirical analysis of the properties of dust-continuum emission
in a sample of 17 galaxies in the early Universe () with
well-sampled far-infrared (FIR) spectral energy distributions (SEDs) compiled
from the literature. We place our results into context by self-consistently
comparing to samples of nearby star-forming galaxies, luminous infrared
galaxies (LIRGs), and quasars. With the exception of two sources, we find no
significant evolution in the dust emissivity index across cosmic time,
measuring a consistent value of at ,
suggesting the effective dust properties do not change dramatically for most
galaxies. Despite having comparable stellar masses, we find the high-redshift
galaxies to be similar to, or even more extreme than, LIRGs in the HERUS sample
in terms of dust temperature () and IR
luminosity (). We find the dust
temperature evolves mildly towards high redshift, though the LIRGs and quasars
exhibit elevated temperatures indicating a more efficient and/or additional
heating mechanism. Where available, we compare stellar-mass estimates to our
inferred dust masses, whose degeneracy with dust temperature can only be
mitigated with a well-constrained SED. In merely half of the cases the dust
yield may be explained by supernovae alone, with four sources ()
significantly exceeding a highly optimistic yield where . We discuss possible explanations for this apparent inconsistency and
potential observational biases in the measurements of the dust properties of
high-redshift galaxies, including in the current IR-bright sample.Comment: 14 pages, 8 figures. Accepted for publication in Monthly Notices of
the Royal Astronomical Societ
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
An ALMA view of galaxies in the Epoch of Reionisation
No full textIn the past decade hundreds of galaxies have been identified in the Epoch of Reionisation, selected from their rest-frame UV light, using HST and ground-based optical/NIR observatories. Only a handful of these sources, however, have spectroscopic redshift determinations and we have limited understanding of their physical properties.ALMA is currently transforming this field by confirming the redshifts of galaxies out to z=9 and providing the first view of the dust obscured star-formation, the kinematics of these sources, the cool gas traced by [CII] and highly ionised gas traced by [OIII]. In this talk I will discuss new and recent results on the UV-bright galaxy population during the first billion years of cosmic time and what they imply for their observational and physical properties. Finally, I will discuss what might be expected from the upcoming REBELS ALMA large program (approved for Cycle 7) that aims to perform the first systematic ALMA line survey in galaxies within the Epoch of Reionisation.</p
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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