1,721,039 research outputs found
The Cosmic Evolution Survey (COSMOS): The relationships between galaxy morphology, colors, mass and environment at z ∼ 0.7
No full textWe present a detailed analysis of the evolution of the rest-frame B-band morphology of K-selected galaxies with 0 < z < 2.5. This work is based on the K20 spectroscopic sample (Ks < 20) located within the Chandra Deep Field South area, coupled with the public deep GOODS (Great Observatories Origins Deep Surveys) Hubble Space Telescope (HST)+Advanced Camera for Surveys (ACS) multiband optical imaging available in that field. Thanks to the spectroscopic completeness of this catalogue reaching 94 per cent, we can compare the morphological and spectroscopic properties of galaxies with unprecedented detail. Our morphological analysis includes visual inspection and automatic procedures using both parametric (e.g. the Sérsic indices treated by the GALFIT and GASPHOT packages) and non-parametric (concentration, asymmetry and clumpiness, CAS) methods. By exploiting the four-band deep ACS imaging we account in detail for morphological K-correction as a function of the redshift and show that, while parametric methods do not efficiently separate early- and late-type galaxies, non-parametric ones prove more efficient and reliable. Our analysis classifies the K20 galaxies as: 60/300 (20 per cent, class 1) normal ellipticals/S0 14/300 (4 per cent, class 2) perturbed or peculiar ellipticals; 80/300 (27 per cent, class 3) normal spirals; 48/300 (16 per cent, class 4) perturbed or actively star-forming spirals; 98/300 (33 per cent, class 5) irregulars. The morphological and spectroscopic classifications are compatible with each other for more than 90 per cent of the sample galaxies, while seven class-1 E/S0 objects show emission lines and 11 spirals and irregulars (classes 3+4+5) have purely absorption-line spectra. The evolution of the merging fraction is constrained up to z~ 2, by carefully accounting the effects of morphological K-correction: both asymmetry criterion and pair statistics show an increasing merging fraction as a function of redshift. We finally analyse the redshift dependence of the effective radii for early- and late-type galaxies and find some mild evidence for a decrease with z of the early-type galaxy sizes, while the discs and irregulars remain constant. Altogether, this analysis of the K20 sample indicates the large predominance of spirals and irregulars at 0.5 < z < 1.5 in K-band selected samples at even moderate depths
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
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
New methods and selection methods
No full textInternational audienceAs the topics of study of Ly α emitters evolve, new selection methods are being developed to find these high redshift galaxies. In this proceedings, three new methods are presented, based on large integral field unit spectrographs, ultradeep slit spectroscopy and serendipitous discoveries
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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