537 research outputs found

    The NGC 4013 tale: a pseudo-bulged, late-type spiral shaped by a major merger

    Full text link
    Many spiral galaxy haloes show stellar streams with various morphologies when observed with deep images. The origin of these tidal features is discussed, either coming from a satellite infall or caused by residuals of an ancient, gas-rich major merger. By modelling the formation of the peculiar features observed in the NGC 4013 halo, we investigate their origin. By using GADGET -2 with implemented gas cooling, star formation, and feedback, we have modelled the overall NGC 4013 galaxy and its associated halo features. A gas-rich major merger occurring 2.7-4.6 Gyr ago succeeds in reproducing the NGC 4013 galaxy properties, including all the faint stellar features, strong gas warp, boxy-shaped halo and vertical 3.6 mum luminosity distribution. High gas fractions in the progenitors are sufficient to reproduce the observed thin and thick discs, with a small bulge fraction, as observed. A major merger is able to reproduce the overall NGC 4013 system, including the warp strength, the red colour and the high stellar mass density of the loop, while a minor merger model cannot. Because the gas-rich model suffices to create a pseudo-bulge with a small fraction of the light, NGC 4013 is perhaps the archetype of a late-type galaxy formed by a relatively recent merger. Then late type, pseudo-bulge spirals are not mandatorily made through secular evolution, and the NGC 4013 properties also illustrate that strong warps in isolated galaxies may well occur at a late phase of a gas-rich major merger.Comment: 11 pages,9 figures,accepted for publication in MNRA

    Empirical study on flow experience in China tourism e-commerce market

    Get PDF
    Purpose: While tourism e-commerce develops rapidly in China, these channels are truly new to both web providers and web consumers, understanding the nature of these media attaches greater importance. This study investigates the mediation effects of flow experience on the relationship between motivation and behavior intention in tourism e-commerce. Design/methodology/approach: Based on the technology acceptance model, an empirical study is designed to test this relationship. We estimated the measurement model with 13 manifest indicators and 4 latent constructs by CFA to assess the reliability and validity of the construct measures, then tested hypotheses by OLS regression and a formal three-step mediation procedure. Findings: Overall, the results reveal that trust is incorporated in motivation and play it’s role together with other motivations; telepresence and concentration are confirmed in flow experience, and both partially mediated the relationship. Research limitations/implications: This study demonstrates that to improve consumers’ usage adoption, marketers should pay much attention to not only consumers’ motivation but also the areas such as flow experiencePeer Reviewe

    Outstanding supercapacitive properties of Mn-doped TiO2 micro/nanostructure porous film prepared by anodization method.

    Get PDF
    Mn-doped TiO2 micro/nanostructure porous film was prepared by anodizing a Ti-Mn alloy. The film annealed at 300 °C yields the highest areal capacitance of 1451.3 mF/cm(2) at a current density of 3 mA/cm(2) when used as a high-performance supercapacitor electrode. Areal capacitance retention is 63.7% when the current density increases from 3 to 20 mA/cm(2), and the capacitance retention is 88.1% after 5,000 cycles. The superior areal capacitance of the porous film is derived from the brush-like metal substrate, which could greatly increase the contact area, improve the charge transport ability at the oxide layer/metal substrate interface, and thereby significantly enhance the electrochemical activities toward high performance energy storage. Additionally, the effects of manganese content and specific surface area of the porous film on the supercapacitive performance were also investigated in this work

    Housing development and urbanisation in China

    Get PDF
    Rapid urbanisation and rising income have led to a strong demand for housing in urban China. However, housing development has been distorted by speculation, income inequality and lack of government support for low-cost houses. In recent years, house prices become so high, making the vast majority of urban residents unable to afford, whereas rich families are able to buy many and leave them vacant. Income inequality is a major cause for rising house prices, which, in turn, exaggerates income inequality further. This vicious relationship has caused social tension between the rich and the poor and unhappiness among the middle- and low-income groups. This paper discusses the factors responsible for the housing bubble in China and recommends appropriate policies to resolve this problem

    The Determinants Of Corporate Social Responsibility Disclosure: Evidence From China

    Get PDF
    Employing the content analysis approach, this paper aims to identify the determinants of corporate social responsibility disclosure (CSRD) in China using the annual reports of over 800 A-share listed firms on the Shanghai Stock Exchange. We find that CSRD is positively associated with firm size, media exposure, share ownership concentration and institutional shareholding. Moreover, firms in High-Profile environmentally sensitive industries tend to disclose more corporate social responsibility (CSR) information than those in Low-Profile environmentally sensitive industries, supporting the view that political cost is the primary constraint for Chinese listed firms. Our results provide important insights for academics interested in the CSR issue in emerging economies, for enterprise managers interested in exploiting the annual reports as a strategy to legitimize their corporate social conduct, and for government regulators committed to improving CSR activities and information disclosure

    Could M31 be the result of a major merger?

    Full text link
    We investigated a scenario in which M31 could be the remnant of a gas-rich major merger. Galaxy merger simulations, highly constrained by observations, were run using GADGET 2 in order to reproduce M31. We succeeded in reproducing the global shape of M31, the thin disk and the bulge, and in addition some of the main M31 large-scale features, such as the thick disk, the 10kpc ring and the Giant Stream. This lead to a new explanation of the Giant Stream which could be caused by tidal tail stars that have been captured by the galaxy potential.Comment: Proceedings for the conference "Assembling the puzzle of the Milky Way", 2 page
    • …
    corecore