4,041 research outputs found
Modeling the JWST high-redshift galaxies with a general formation scenario and the consistency with the CDM model
Early results from the James Webb Space Telescope (JWST) observations have
hinted at two traces beyond the standard cosmological framework. One is the
extraordinarily high stellar masses and their density at ,
another is the unexpected abundance of ultra-violet (UV) bright galaxies at
. Nevertheless, both pieces of evidence are not statistically robust,
yet. In this work, we construct rest-frame UV luminosity functions (LFs) based
on a general formation model for these high-redshift galaxy candidates, since
UV LFs always carry the information of stellar formation efficiency (SFE),
initial mass function (IMF), dust attenuation, and other crucial elements for
galaxy evolution. By updating the massive galaxies candidates with
spectroscopic observations and exploring the parameter space of SFE, we are
able to reasonably explain the cumulative stellar mass density within the
redshift range of , with only one galaxy exhibiting unusual
characteristics. We also reveal a potential non-monotonic trend of SFE with the
increasing redshift. At higher redshift (), bright UV LFs can be well
fitted with non-dust attenuation or Top-heavy IMF for Population III stars. The
Population III star scenario can also naturally account for the possible dip of
SFE at .Comment: 9 pages, 4 figures, and 1 tabl
A Hybrid-Extragradient Scheme for System of Equilibrium Problems, Nonexpansive Mappings, and Monotone Mappings
We introduce a new iterative scheme based on both hybrid method and extragradient method for finding a common element of the solutions set of a system of equilibrium problems, the fixed points set of a nonexpansive mapping, and the solutions set of a variational inequality problems for a monotone and -Lipschitz continuous mapping in a Hilbert space. Some convergence results for the iterative sequences generated by these processes are obtained. The results in this paper extend and improve some known results in the literature.</p
Knowledge Sharing in Virtual Community: The Comparison between Contributors and Lurkers
Internet-based virtual communities are growing with an unprecedented rate. Virtual communities have been viewed as platforms for sharing knowledge. The present study proposed an integrated model by investigating social capital and motivational factors that would influence the knowledge sharing attitude of members. Data were collected from 207 professional virtual community users (including 53 contributors and 154 lurkers). The results showed that trust and pro-sharing norms mediate the relationship between shared understanding and knowledge sharing attitude. Enjoy helping, commitment, and community-related outcome expectations enhance contributors’ attitudes toward knowledge sharing. When lurkers perceived more reciprocity in their communities and expect more community-related outcome, they incline to sharing knowledge with others. The implications of these results are discussed
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