Internal Variations in Empirical Oxygen Abundances for Giant HII Regions in the Galaxy NGC 2403

This paper presents a spectroscopic investigation of 11 HII regions in the nearby galaxy NGC 2403. The HII regions are observed with a long-slit spectrograph mounted on the 2.16 m telescope at XingLong station of National Astronomical Observatories of China. For each of the HII regions, spectra are extracted at different nebular radii along the slit-coverage. Oxygen abundances are empirically estimated from the strong-line indices R23, N2O2, O3N2, and N2 for each spectrophotometric unit, with both observation- and model-based calibrations adopted into the derivation. Radial profiles of these diversely estimated abundances are drawn for each nebula. In the results, the oxygen abundances separately estimated with the prescriptions on the basis of observations and models, albeit from the same spectral index, systematically deviate from each other; at the same time, the spectral indices R23 and N2O2 are distributed with flat profiles, whereas N2 and O3N2 exhibit apparent gradients with the nebular radius. Because our study naturally samples various ionization levels which inherently decline at larger radii within individual HII regions, the radial distributions indicate not only the robustness of R23 and N2O2 against ionization variations but also the sensitivity of N2 and O3N2 to the ionization parameter. The results in this paper provide observational corroboration of the theoretical prediction about the deviation in the empirical abundance diagnostics. Our future work is planned to investigate metal-poor HII regions with measurable T_e, in an attempt to recalibrate the strong-line indices and consequently disclose the cause of the discrepancies between the empirical oxygen abundances.Comment: 16 pages, 10 figures, 5 tables; accepted for publication in The Astrophysical Journal; with a minor correction in the tex

Characterizing Ultraviolet and Infrared Observational Properties for Galaxies. II. Features of Attenuation Law

Variations in the attenuation law have a significant impact on observed spectral energy distributions for galaxies. As one important observational property for galaxies at ultraviolet and infrared wavelength bands, the correlation between infrared-to-ultraviolet luminosity ratio and ultraviolet color index (or ultraviolet spectral slope), i.e., the IRX-UV relation (or IRX-beta relation), offered a widely used recipe for correcting dust attenuation in galaxies, but the usability appears to be in doubt now because of considerable dispersion in this relation found by many studies. In this paper, on the basis of spectral synthesis modeling and spatially resolved measurements of four nearby spiral galaxies, we provide an interpretation of the deviation in the IRX-UV relation with variations in the attenuation law. From both theoretical and observational viewpoints, two components in the attenuation curve, the linear background and the 2175 Angstrom bump, are suggested to be the parameters in addition to the stellar population age (addressed in the first paper of this series) in the IRX-UV function; different features in the attenuation curve are diagnosed for the galaxies in our sample. Nevertheless, it is often difficult to ascertain the attenuation law for galaxies in actual observations. Possible reasons for preventing the successful detection of the parameters in the attenuation curve are also discussed in this paper, including the degeneracy of the linear background and the 2175 Angstrom bump in observational channels, the requirement for young and dust-rich systems to study, and the difficulty in accurate estimates of dust attenuations at different wavelength bands.Comment: 25 pages, 23 figures, 5 tables; accepted for publication in The Astrophysical Journa

The Business Value of CRM Technology: From the Perspective of Organizational Ambidexterity

In this paper we report a case study on how firms realize the business value of CRM by developing CRM-enabled ambidexterity to simultaneously pursue stability and develop adaptability. Results show that as the focal firm used CRM as a platform for standardizing operations and building routines, the top management team (TMT) and the operation team worked together to reflexively monitor the status of CRM-enabled capabilities and the usage of CRM. Such reflexive monitoring led to proactive changes in CRM and CRM usage in response to market changes and market needs, ensuring adaptability. In this way CRM enabled organizational ambidexterity through mechanisms of capabilities building and reflexive monitoring. By examining the previously unexplored relationship between CRM use and organizational ambidexterity, this study contributes to literature in both ambidexterity and CRM business value

Multiwavelength Bulge-Disk Decomposition for the Galaxy M81 (NGC 3031). I. Morphology

A panchromatic investigation of morphology for the early-type spiral galaxy M81 is presented in this paper. We perform bulge-disk decomposition in M81 images at totally 20 wavebands from FUV to NIR obtained with GALEX, Swift, SDSS, WIYN, 2MASS, WISE, and Spitzer. Morphological parameters such as Sersic index, effective radius, position angle, and axis ratio for the bulge and the disk are thus derived at all the wavebands, which enables quantifying the morphological K-correction for M81 and makes it possible to reproduce images for the bulge and the disk in the galaxy at any waveband. The morphology as a function of wavelength appears as a variable-slope trend of the Sersic index and the effective radius, in which the variations are steep at UV--optical and shallow at optical--NIR bands; the position angle and the axis ratio keep invariable at least at optical--NIR bands. It is worth noting that, the Sersic index for the bulge reaches to about 4--5 at optical and NIR bands, but drops to about 1 at UV bands. This difference brings forward a caveat that, a classical bulge is likely misidentified for a pseudo-bulge or no bulge at high redshifts where galaxies are observed through rest-frame UV channels with optical telescopes. The next work of this series is planned to study spatially resolved SEDs for the bulge and the disk, respectively, and thereby explore stellar population properties and star formation/quenching history for the the galaxy composed of the subsystems.Comment: 48 Pages, 38 Figures, 5 Tables; Accepted for Publication in The Astrophysical Journal Supplement Serie

TREA: Tree-Structure Reasoning Schema for Conversational Recommendation

Conversational recommender systems (CRS) aim to timely trace the dynamic interests of users through dialogues and generate relevant responses for item recommendations. Recently, various external knowledge bases (especially knowledge graphs) are incorporated into CRS to enhance the understanding of conversation contexts. However, recent reasoning-based models heavily rely on simplified structures such as linear structures or fixed-hierarchical structures for causality reasoning, hence they cannot fully figure out sophisticated relationships among utterances with external knowledge. To address this, we propose a novel Tree structure Reasoning schEmA named TREA. TREA constructs a multi-hierarchical scalable tree as the reasoning structure to clarify the causal relationships between mentioned entities, and fully utilizes historical conversations to generate more reasonable and suitable responses for recommended results. Extensive experiments on two public CRS datasets have demonstrated the effectiveness of our approach.Comment: Accepted by ACL2023 main conferenc

Decreased Filamin b expression regulates trophoblastic cells invasion through ERK/MMP-9 pathway in pre-eclampsia

Objectives: The purpose of this study was to investigate the expression of Filamin b in the placental placenta of patients with early or late onset pre-eclampsia (PE) and its potential effects on the pathophysiology of the disease. Methods and methods: Immunohistochemistry staining, western blot assays and real time PCR were used to detect the expression level of FLN-b. The expression levels of MMP-2, MMP-9 and ERK1/2 proteins from control and FLN-b-silenced JEG-3 cells were also detected by western blot and JEG-3 cell invasion. Results: Compared with normal term pregnancies placentas, the FLN-b expression was significantly lower than that of women with PE, its level in late-onset PE is lower than in early-onset PE. In FLN-b-silenced JEG-3 cells, the protein levels of MMP-2, MMP-9 and phosphorylated ERK1/2 decreased markedly and the number of cells penetrating through the transwell chamber membrane is also greatly reduced. Conclusions: Down-regulation of FLN-b inhibits the ERK/MMP-2 and MMP-9 pathways, leading to trophoblastic invasion disorders in the PE placenta.

Regulation of gastric epithelial cell homeostasis by gastrin and bone morphogenetic protein signaling

We reported that transgenic expression of the bone morphogenetic protein (BMP) signaling inhibitor noggin in the mouse stomach, leads to parietal‐cell (PC) loss, expansion of transitional cells expressing markers of both mucus neck and zymogenic lineages, and to activation of proliferative mechanisms. Because these cellular changes were associated with increased levels of the hormone gastrin, we investigated if gastrin mediates the expression of the phenotypic changes of the noggin transgenic mice (NogTG mice). Three‐month‐old NogTG mice were crossed to gastrin‐deficient (GasKO mice) to generate NogTG;GasKO mice. Morphology of the corpus of wild type, NogTG, GasKO, and NogTG;GasKO mice was analyzed by H&E staining. Distribution of PCs and zymogenic cells (ZCs) was analyzed by immunostaining for the H+/K+‐ATPase and intrinsic factor (IF). Expression of the H+/K+‐ATPase and IF genes and proteins were measured by QRT‐PCR and western blots. Cell proliferation was assessed by immunostaining for proliferating cell nuclear antigen. The corpus of the NogTG;GasKO mice displayed a marked reduction in the number of PCs and ZCs in comparison to NogTG mice. Further, cellular proliferation was significantly lower in NogTG;GasKO mice, than in the NogTG mice. Thus, gastrin mediates the increase in gastric epithelial cell proliferation induced by inhibition of BMP signaling in vivo. Moreover, gastrin and BMP signaling exert cooperative effects on the maturation and differentiation of both the zymogenic and PC lineages. These findings contribute to a better understanding of the factors involved in the control of gastric epithelial cell homeostasis.We investigated the role of gastrin and BMP signaling in the regulation of gastric epithelial homeostasis by crossing mice expressing the BMP inhibitor noggin in the stomach (NogTG mice) to gastrin‐deficient mice (GasKO mice). Analysis of these animals indicates that gastrin mediates the increase in gastric epithelial cell proliferation induced by inhibition of BMP signaling in vivo. Moreover, gastrin and BMP signaling exert cooperative effects on the maturation and differentiation of both the zymogenic and parietal‐cell lineages.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/113157/1/phy212501.pd