225 research outputs found

    Consumer Reaction and the Effectiveness of Celebrity Endorsed Advertising: A Survey-Based Econometric Analysis

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    In this study, we apply an econometric methodology to empirically examine the potential roles of a host of key factors on the part of the consumer in affecting the level of effectiveness (persuasiveness) of celebrity endorsement in advertising. Based on first-hand data obtained from surveys and using an econometric approach, we design and implement our empirical analysis. The analysis leads to estimation results showing that gender of the consumer matters critically in determining the level of effectiveness that persuasion of celebrity endorsed advertising could possibly reach. Through our regression exercise, we also find that the effectiveness of celebrity endorsed advertising crucially depends on the level of consumer income. In addition, our regression results also suggest that the socio-cultural background of the consumer plays a critical role in affecting the persuasiveness level of celebrity endorsed advertising

    An emerging model for virtual international academic conference in architecture, engineering, and construction

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    © 2021 The Authors. Published by Frontiers Media. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.3389/fbuil.2021.701755Academic conferences are very important to industrial development and academic scholars. However, the coronavirus disease 2019 pandemic has led to the cancellation of many international conferences; thus, virtual conferences have received a great deal of attention. Their expanding role has created an urgent need to explore the best approaches for successful execution. However, there is limited empirical evidence on the organization of these conferences. This study aims to offer a comprehensive analysis of the key success factors through a case study of the International Group for Lean Construction’s first virtual conference. The results revealed the influence of multiple factors. In addition, a successful model for an international virtual academic conference is proposed. The model contributes to the knowledge of sustainable development in engineering management and architecture, engineering, and construction practice.Published onlin

    A Galactomannoglucan Derived from Agaricus brasiliensis: Purification, Characterization and Macrophage Activation via MAPK and IkappaB/NFkappaB Pathways

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    In this study, a novel galactomannoglucan named as TJ2 was isolated from Agaricus brasiliensis with microwave extraction, macroporous resin, ion exchange resin and high resolution gel chromatography. TJ2 is composed of glucose, mannose and galactose in the ratio 99.2:0.2:0.6. Infrared spectra (IR), methylation analysis and nuclear magnetic resonance spectra indicated that TJ2 mainly contained a b-(1?3) – linked glucopyranosyl backbone. Interestingly, TJ2 significantly promoted RAW264.7 cell proliferation, and was able to activate the cells to engulf E. coli. In addition, TJ2 induced the expression of Interleukin 1b (IL-1b), Interleukin 6 (IL-6), tumor necrosis factor a (TNF-a) and cyclooxygenase-2 (Cox-2) in the cells. TJ2 also promoted the production of nitric oxide (NO) by inducing the expression of inducible nitric oxide synthase (iNOS). Moreover, TJ2 is a potent inducer in activating the mitogen-activated protein kinase (MAPK) and inhibitor of nuclear factor-kappa B (IkappaB)/nuclear factor-kappa B (NFkappaB) pathways

    Extremely large magnetoresistance in topologically trivial semimetal α\alpha-WP2_2

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    Extremely large magnetoresistance (XMR) was recently discovered in many non-magnetic materials, while its underlying mechanism remains poorly understood due to the complex electronic structure of these materials. Here, we report an investigation of the α\alpha-phase WP2_2, a topologically trivial semimetal with monoclinic crystal structure (C2/m), which contrasts to the recently discovered robust type-II Weyl semimetal phase in β\beta-WP2_2. We found that α\alpha-WP2_2 exhibits almost all the characteristics of XMR materials: the near-quadratic field dependence of MR, a field-induced up-turn in resistivity following by a plateau at low temperature, which can be understood by the compensation effect, and high mobility of carriers confirmed by our Hall effect measurements. It was also found that the normalized MRs under different magnetic fields has the same temperature dependence in α\alpha-WP2_2, the Kohler scaling law can describe the MR data in a wide temperature range, and there is no obvious change in the anisotropic parameter γ\gamma value with temperature. The resistance polar diagram has a peanut shape when field is rotated in ac\textit{ac} plane, which can be understood by the anisotropy of Fermi surface. These results indicate that both field-induced-gap and temperature-induced Lifshitz transition are not the origin of up-turn in resistivity in the α\alpha-WP2_2 semimetal. Our findings establish α\alpha-WP2_2 as a new reference material for exploring the XMR phenomena.Comment: 18 pages, 12 figure

    Effects of oxygen enrichment on diesel spray flame soot formation in O<sub>2</sub>/Ar atmosphere

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    In this study, diesel spray combustion at oxygen-enriched conditions (oxygen volume fraction of 21–70 %) with argon dilution is experimentally investigated in a constant-volume combustion chamber. Optical diagnostics are employed to study flame development, stabilization, and soot formation at oxygen-enriched conditions. To further verify the experimental observations, two-stage Lagrangian simulations are used to analyze the effects of oxygen on the formation and oxidation of soot precursors, polycyclic aromatic hydrocarbons. Results show that replacing nitrogen in air by argon leads to a 50 % reduction of the flame lift-off length, an increased soot flame temperature by 300 K, and higher soot concentrations. Flame morphology and structure still follow the classic conventional diesel combustion model in the oxygen range of 21–40 %, while changes are observed when oxygen levels are higher than 50 %. The width and length of the soot flame are shortened, and chemiluminescence from intermediate species like CO dominates the flame natural luminosity at the spray head, where the flame temperature reaches near 3000 K. Soot reduction mechanisms at high-degree oxygen-enrichment conditions are investigated. The intrinsic mixing-limited combustion of diesel sprays leads to unavoidable fuel-rich areas locally, but the shortened flame lift-off length and sufficient oxygen supply confines soot-forming conditions to a smaller, upstream region. The residence time of fuel parcels in this confined soot-forming area is shortened due to the larger local spray velocity. Thereafter, fuel parcels enter a high-temperature fuel-lean region, where the formed soot is oxidized rapidly.</p

    Effects of oxygen enrichment on diesel spray flame soot formation in O<sub>2</sub>/Ar atmosphere

    Get PDF
    In this study, diesel spray combustion at oxygen-enriched conditions (oxygen volume fraction of 21–70 %) with argon dilution is experimentally investigated in a constant-volume combustion chamber. Optical diagnostics are employed to study flame development, stabilization, and soot formation at oxygen-enriched conditions. To further verify the experimental observations, two-stage Lagrangian simulations are used to analyze the effects of oxygen on the formation and oxidation of soot precursors, polycyclic aromatic hydrocarbons. Results show that replacing nitrogen in air by argon leads to a 50 % reduction of the flame lift-off length, an increased soot flame temperature by 300 K, and higher soot concentrations. Flame morphology and structure still follow the classic conventional diesel combustion model in the oxygen range of 21–40 %, while changes are observed when oxygen levels are higher than 50 %. The width and length of the soot flame are shortened, and chemiluminescence from intermediate species like CO dominates the flame natural luminosity at the spray head, where the flame temperature reaches near 3000 K. Soot reduction mechanisms at high-degree oxygen-enrichment conditions are investigated. The intrinsic mixing-limited combustion of diesel sprays leads to unavoidable fuel-rich areas locally, but the shortened flame lift-off length and sufficient oxygen supply confines soot-forming conditions to a smaller, upstream region. The residence time of fuel parcels in this confined soot-forming area is shortened due to the larger local spray velocity. Thereafter, fuel parcels enter a high-temperature fuel-lean region, where the formed soot is oxidized rapidly.</p
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