Reinvestigating the Relationship between Information Technology Capability and Firm Performance: Focusing On the Impact of the Adoption of Enterprise Systems

Though many information systems researchers have made various attempts to investigate the relationship between information technology capability and firm performance from diverse perspectives, we have not come to a conclusion yet with some mixed results. In this research, focusing on the adoption of Enterprise Resource Planning systems by firms as a proxy measure of information technology capability, we re-examine whether the association is positive or negative. With the sample of Korean firms which have adopted Enterprise Resource Planning (ERP) systems in 2009, we match ERP adopters and non-adopters with propensity score matching, and compare financial performance between them with difference-in-difference estimation between pre- and post-adoption period. According to our analysis, we find out that there is no positive and significant relationship between information technology capability and firm performance in profit ratios. This research shows that contrary to the era of propriety information systems, standardized information systems make no more competitive advantages against competitors these days

Searching for MgII absorbers in and around galaxy clusters

To study environmental effects on the circumgalactic medium (CGM), we use the samples of redMaPPer galaxy clusters, background quasars and cluster galaxies from the SDSS. With ~82 000 quasar spectra, we detect 197 MgII absorbers in and around the clusters. The detection rate per quasar is 2.7$\pm$0.7 times higher inside the clusters than outside the clusters, indicating that MgII absorbers are relatively abundant in clusters. However, when considering the galaxy number density, the absorber-to-galaxy ratio is rather low inside the clusters. If we assume that MgII absorbers are mainly contributed by the CGM of massive star-forming galaxies, a typical halo size of cluster galaxies is smaller than that of field galaxies by 30$\pm$10 per cent. This finding supports that galaxy haloes can be truncated by interaction with the host cluster.Comment: 11 pages, 12 figures. To appear in MNRA

Understanding the Formation and Evolution of Dark Galaxies in a Simulated Universe

We study the formation and evolution of dark galaxies using the IllustrisTNG cosmological hydrodynamical simulation. We first identify dark galaxies with stellar-to-total mass ratios, $M_* / M_{\text{tot}}$, smaller than $10^{-4}$, which differ from luminous galaxies with $M_* / M_{\text{tot}} \geq 10^{-4}$. We then select the galaxies with dark matter halo mass of $\sim 10^9 \, h^{-1}$$\rm M_{\odot}$ for mass completeness, and compare their physical properties with those of luminous galaxies. We find that at the present epoch ($z=0$), dark galaxies are predominantly located in void regions without star-forming gas. We also find that dark galaxies tend to have larger sizes and higher spin parameters than luminous galaxies. In the early universe, dark and luminous galaxies show small differences in the distributions of spin and local environment estimates, and the difference between the two samples becomes more significant as they evolve. Our results suggest that dark galaxies tend to be initially formed in less dense regions, and could not form stars because of heating from cosmic reionization and of few interactions and mergers with other systems containing stars unlike luminous galaxies. This study based on numerical simulations can provide important hints for validating dark galaxy candidates in observations and for constraining galaxy formation models.Comment: 15 pages, 10 figures, accepted for publication in Ap

How people perceive malicious comments differently: factors influencing the perception of maliciousness in online news comments

This study proposes a comprehensive model to investigate the factors that influence the perceived maliciousness of online news comments. The study specifically examines individual factors, including demographic characteristics (e.g., gender and age), personality traits (e.g., empathy and attitudes toward online news comments), and reading-related factors (e.g., the amount of news comment reading). Contextual factors such as issue involvement, perceived peer behavior, and the presence of malicious comments in news articles are also considered. The results suggest that most of the proposed variables have a significant impact on the perceived maliciousness of online news comments, except for morality and issue involvement. The findings have important theoretical implications for research on malicious online news comments and provide practical guidelines for online news platforms on how to reduce malicious comments by visualizing them alongside other news comments

Merging Rates of the First Objects and the Formation of First Mini-Filaments in Models with Massive Neutrinos

We study the effect of massive neutrinos on the formation and evolution of the first filaments containing the first star-forming halos of mass M~10^{6}M_sun at z~20. With the help of the extended Press-Schechter formalism, we evaluate analytically the rates of merging of the first star-forming halos into zero-dimensional larger halos and one-dimensional first filaments. It is shown that as the neutrino mass fraction f_{\nu} increases, the halo-to-filament merging rate increases while the halo-to-halo merging rate decreases sharply. For f_{\nu}<=0.04, the halo-to-filament merging rate is negligibly low at all filament mass scales, while for f_{\nu}>=0.07 the halo-to-filament merging rate exceeds 0.1 at the characteristic filament mass scale of ~10^{9}M_sun. The distribution of the redshifts at which the first filaments ultimately collapse along their longest axes is derived and found to have a sharp maximum at z~8. We also investigate the formation and evolution of the second generation filaments which contain the first galaxies of mass 10^{9}M_sun at z=8 as the parent of the first generation filaments. A similar trend is found: For f_{\nu}>= 0.07 the rate of clustering of the first galaxies into the second-generation filaments exceeds 0.3 at the characteristic mass scale of ~10^{11}M_sun. The longest-axis collapse of these second-generation filaments are found to occur at z~3. The implications of our results on the formation of massive high-z galaxies and the early metal enrichment of the intergalactic media by supernova-driven outflows, and possibility of constraining the neutrino mass from the mass distribution of the high-z central blackholes are discussed.Comment: Accepted for publication in ApJ, mistakes in the calculation of the merging rates corrected, feasibility study of constraining neutrino mass with high-z quasar luminosity function presented, discussion improved, 7 figure

Modeling the Alignment Profile of Satellite Galaxies in Clusters

Analyzing the halo and galaxy catalogs from the Millennium simulations at redshifts $z=0,\ 0.5,\ 1$, we determine the alignment profiles of cluster galaxies by measuring the average alignments between the major axes of the pseudo inertia tensors from all satellites within cluster's virial radius and from only those satellites within some smaller radius as a function of the top-hat scale difference. The alignment profiles quantify how well the satellite galaxies retain the memory of the external tidal fields after merging into their host clusters and how fast they lose the initial alignment tendency as the cluster's relaxation proceeds. It is found that the alignment profile drops faster at higher redshifts and on smaller mass scales. This result is consistent with the picture that the faster merging of the satellites and earlier onset of the nonlinear effect inside clusters tend to break the preferential alignments of the satellites with the external tidal fields. Modeling the alignment profile of cluster galaxies as a power-law of the density correlation coefficient that is independent of the power spectrum normalization ($\sigma_{8}$) and demonstrating that the density correlation coefficient varies sensitively with the density parameter ($\Omega_{m}$) and neutrino mass fraction ($f_{\nu}$), we suggest that the alignment profile of cluster galaxies might be useful for breaking the $\Omega_{m}$-$\sigma_{8}$ and $f_{\nu}$-$\sigma_{8}$ degeneracies.Comment: accepted for publication in ApJ, Introduction and Conclusion sections improved, mistakes in plotting the figures corrected, detailed explanations for the dependence of the alignment profiles on the mass and redshift provided, 7 figures, 3 table

Massive Neutrinos Promote the Size Growth of Early-Type Galaxies

The effect of massive neutrinos on the evolution of the early type galaxies (ETGs) in size ($R_{e}$) and stellar mass ($M_{\star}$) is explored by tracing the merging history of galaxy progenitors with the help of the robust semi-analytic prescriptions. We show that as the presence of massive neutrinos plays a role of enhancing the mean merger rate per halo, the high-$z$ progenitors of a descendant galaxy with fixed mass evolves much more rapidly in size for a $\Lambda$MDM ($\Lambda$CDM + massive neutrinos) model than for the $\Lambda$CDM case. The mass-normalized size evolution of the progenitor galaxies, $R_{e}[M_{\star}/(10^{11}M_{\odot})]^{-0.57}\propto (1+z)^{-\beta}$, is found to be quite steep with the power-law index of $\beta\sim 1.5$ when the neutrino mass fraction is $f_{\nu}=0.05$, while it is $\beta\sim 1$ when $f_{\nu}=0$. It is concluded that if the presence and role of massive neutrinos are properly taken into account, it may explain away the anomalous compactness of the high-$z$ ETGs compared with the local ellipticals with similar stellar masses.Comment: accepted for publication in ApJ, 5 figures, discussion improved, direct comparison with observational data adde