276,981 research outputs found
Towards a Provenance Framework for Sub-image Processing for Astronomical Data
No full textJ. Mwebaze, J. McFarland, D. Boxhoorn, E. Valentijn<br/
Author, publisher and bookseller : a tripartite synergy in Nigerian book industry
Full text linkThis work is about the roles of Author, Publisher and Bookseller in Book development in
Nigeria. The paper started by delving into the history of Book Publishing in Nigeria after
which it proceeded by defining who an author, a publisher, and a bookseller is and
expatiated on the indispensable roles of these key actors in Nigerian Book Industry and in
the emerging Information Society. Furthermore, the various constraints to book
development were identified while the paper advised on how the Book Industry can be
further promoted in Nigeria. However, the paper concluded and made recommendations
on how the Book sector can help in enhancing scholarship in the country
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
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
Testing Verlinde's emergent gravity in early-type galaxies
No full textEmergent Gravity (EG) has been proposed to resolve the missing mass problem in galaxies, replacing the potential of dark matter (DM) by the effect of the entropy displacement of dark energy by baryonic matter. This apparent DM depends only on the baryonic mass distribution and the present-day value of the Hubble parameter. In this paper we test the EG proposition, formalized byVerlinde for a spherical and isolated mass distribution using the central dynamics (Sloan Digital Sky Survey velocity dispersion, σ) and the K-band light distribution in a sample of 4032 massive (M* ≳ 1010M O ̇) and local early-type galaxies (ETGs) from the SPIDER datasample. Our results remain unaltered if we consider the sample of 750 roundest field galaxies. Using these observations we derive the predictions by EG for the stellar mass-tolight ratio (M/L) and the initial mass function (IMF). We demonstrate that, consistently with a classical Newtonian framework with a DMhalo component or alternative theories of gravity as MOdified Newtonian Dynamics (MOND), the central dynamics can be fitted if the IMF is assumed non-universal and systematically changing with s. For the case of EG, we find lower, but still acceptable, stellar M/L if compared with the DM-based Navarro, Frenk & White (NFW) model and with MOND, but pretty similar to adiabatically contracted DM haloes and with expectations from spectral gravity-sensitive features. If the strain caused by the entropy displacement would be not maximal, as adopted in the current formulation, then the dynamics of ETGs could be reproduced with larger M/L
Radio emission in cooling flows
No full textIt is reviewed whether cooling flows could fuel central radio sources in spheroidal galaxies as a general, universal mechanism. The radio luminosity functions of S0, E, gE and cD galaxies show a similar scaled dependence on Lopt, demanding a non-exclusive radio powering mechanism for cD's. If cooling flows generate the central radio sources in these objects, then a non-exclusive X-ray halo formation process should occur. Gravitational accretion of gas from the intergalactic medium is identified as such a mechanism for both E+S0's and cD's. From studying a sample of 110 objects the author finds strong evidence for gravitationally driven cooling flows fuelling central radio sources in spheroidal galaxies
The stellar content of the A496 cD galaxy
No full textJ, H, and K radial color distributions obtained for the galaxy A496 cD indicate that while the halo becomes bluer at increasing radii in the B-V, it becomes redder in the visual-IR colors. The combined visual-IR data lead to a unique model for both the main sequence and giant stars in which the main sequence is characterized by a radial increase of an upper mass cutoff, and the giant population is dominated by M4-5III giants. Interpretation of these data in terms of metallicity gradients implies a young population in the halo, while the radial mass cutoff increase, together with the increasing fraction of giant stars, contradicts an aging effect as the reason for the mass cutoff. Several critical predictions of the Valentijn (1983) model, which invokes ongoing star formation out of accreted X-ray gas, are fulfilled
Mining e-mail content for author identification forensics
No full textWe describe an investigation into e-mail content mining for author identification, or authorship attribution, for the purpose of forensic investigation. We focus our discussion on the ability to discriminate between authors for the case of both aggregated e-mail topics as well as across different email topics. An extended set of e-mail document features including structural characteristics and linguistic patterns were derived and, together with a Support Vector Machine learning algorithm, were used for mining the e-mail content. Experiments using a number of e-mail documents generated by different authors on a set of topics gave promising results for both aggregated and multi-topic author categorisation
Radio emission in cooling flows
No full textIt is reviewed whether cooling flows could fuel central radio sources in spheroidal galaxies as a general, universal mechanism. The radio luminosity functions of S0, E, gE and cD galaxies show a similar scaled dependence on Lopt, demanding a non-exclusive radio powering mechanism for cD's. If cooling flows generate the central radio sources in these objects, then a non-exclusive X-ray halo formation process should occur. Gravitational accretion of gas from the intergalactic medium is identified as such a mechanism for both E+S0's and cD's. From studying a sample of 110 objects the author finds strong evidence for gravitationally driven cooling flows fuelling central radio sources in spheroidal galaxies
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